1 /*
   2  * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.javac.jvm;
  27 
  28 import java.io.*;
  29 import java.net.URI;
  30 import java.net.URISyntaxException;
  31 import java.nio.CharBuffer;
  32 import java.nio.file.ClosedFileSystemException;
  33 import java.util.Arrays;
  34 import java.util.EnumSet;
  35 import java.util.HashMap;
  36 import java.util.HashSet;
  37 import java.util.Map;
  38 import java.util.Set;
  39 import java.util.function.IntFunction;
  40 import java.util.function.Predicate;
  41 import java.util.stream.IntStream;
  42 
  43 import javax.lang.model.element.Modifier;
  44 import javax.lang.model.element.NestingKind;
  45 import javax.tools.JavaFileManager;
  46 import javax.tools.JavaFileObject;
  47 
  48 import com.sun.tools.javac.code.Source;
  49 import com.sun.tools.javac.code.Source.Feature;
  50 import com.sun.tools.javac.comp.Annotate;
  51 import com.sun.tools.javac.comp.Annotate.AnnotationTypeCompleter;
  52 import com.sun.tools.javac.code.*;
  53 import com.sun.tools.javac.code.Directive.*;
  54 import com.sun.tools.javac.code.Lint.LintCategory;
  55 import com.sun.tools.javac.code.Scope.WriteableScope;
  56 import com.sun.tools.javac.code.Symbol.*;
  57 import com.sun.tools.javac.code.Symtab;
  58 import com.sun.tools.javac.code.Type.*;
  59 import com.sun.tools.javac.comp.Annotate.AnnotationTypeMetadata;
  60 import com.sun.tools.javac.file.BaseFileManager;
  61 import com.sun.tools.javac.file.PathFileObject;
  62 import com.sun.tools.javac.jvm.ClassFile.Version;
  63 import com.sun.tools.javac.jvm.PoolConstant.NameAndType;
  64 import com.sun.tools.javac.main.Option;
  65 import com.sun.tools.javac.resources.CompilerProperties.Errors;
  66 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
  67 import com.sun.tools.javac.resources.CompilerProperties.Warnings;
  68 import com.sun.tools.javac.util.*;
  69 import com.sun.tools.javac.util.ByteBuffer.UnderflowException;
  70 import com.sun.tools.javac.util.DefinedBy.Api;
  71 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
  72 import com.sun.tools.javac.util.JCDiagnostic.Fragment;
  73 
  74 import static com.sun.tools.javac.code.Flags.*;
  75 import static com.sun.tools.javac.code.Kinds.Kind.*;
  76 
  77 import com.sun.tools.javac.code.Scope.LookupKind;
  78 
  79 import static com.sun.tools.javac.code.TypeTag.ARRAY;
  80 import static com.sun.tools.javac.code.TypeTag.CLASS;
  81 import static com.sun.tools.javac.code.TypeTag.TYPEVAR;
  82 import static com.sun.tools.javac.jvm.ClassFile.*;
  83 import static com.sun.tools.javac.jvm.ClassFile.Version.*;
  84 
  85 import static com.sun.tools.javac.main.Option.PARAMETERS;
  86 
  87 /** This class provides operations to read a classfile into an internal
  88  *  representation. The internal representation is anchored in a
  89  *  ClassSymbol which contains in its scope symbol representations
  90  *  for all other definitions in the classfile. Top-level Classes themselves
  91  *  appear as members of the scopes of PackageSymbols.
  92  *
  93  *  <p><b>This is NOT part of any supported API.
  94  *  If you write code that depends on this, you do so at your own risk.
  95  *  This code and its internal interfaces are subject to change or
  96  *  deletion without notice.</b>
  97  */
  98 public class ClassReader {
  99     /** The context key for the class reader. */
 100     protected static final Context.Key<ClassReader> classReaderKey = new Context.Key<>();
 101 
 102     public static final int INITIAL_BUFFER_SIZE = 0x0fff0;
 103 
 104     private final Annotate annotate;
 105 
 106     /** Switch: verbose output.
 107      */
 108     boolean verbose;
 109 
 110     /** Switch: allow modules.
 111      */
 112     boolean allowModules;
 113 
 114     /** Switch: allow sealed
 115      */
 116     boolean allowSealedTypes;
 117 
 118     /** Switch: allow records
 119      */
 120     boolean allowRecords;
 121 
 122    /** Lint option: warn about classfile issues
 123      */
 124     boolean lintClassfile;
 125 
 126     /** Switch: warn (instead of error) on illegal UTF-8
 127      */
 128     boolean warnOnIllegalUtf8;
 129 
 130     /** Switch: preserve parameter names from the variable table.
 131      */
 132     public boolean saveParameterNames;
 133 
 134     /**
 135      * The currently selected profile.
 136      */
 137     public final Profile profile;
 138 
 139     /** The log to use for verbose output
 140      */
 141     final Log log;
 142 
 143     /** The symbol table. */
 144     Symtab syms;
 145 
 146     Types types;
 147 
 148     /** The name table. */
 149     final Names names;
 150 
 151     /** Access to files
 152      */
 153     private final JavaFileManager fileManager;
 154 
 155     /** Factory for diagnostics
 156      */
 157     JCDiagnostic.Factory diagFactory;
 158 
 159     DeferredCompletionFailureHandler dcfh;
 160 
 161     /**
 162      * Support for preview language features.
 163      */
 164     Preview preview;
 165 
 166     /** The current scope where type variables are entered.
 167      */
 168     protected WriteableScope typevars;
 169 
 170     private List<InterimUsesDirective> interimUses = List.nil();
 171     private List<InterimProvidesDirective> interimProvides = List.nil();
 172 
 173     /** The path name of the class file currently being read.
 174      */
 175     protected JavaFileObject currentClassFile = null;
 176 
 177     /** The class or method currently being read.
 178      */
 179     protected Symbol currentOwner = null;
 180 
 181     /** The module containing the class currently being read.
 182      */
 183     protected ModuleSymbol currentModule = null;
 184 
 185     /** The buffer containing the currently read class file.
 186      */
 187     ByteBuffer buf = new ByteBuffer(INITIAL_BUFFER_SIZE);
 188 
 189     /** The current input pointer.
 190      */
 191     protected int bp;
 192 
 193     /** The pool reader.
 194      */
 195     PoolReader poolReader;
 196 
 197     /** The major version number of the class file being read. */
 198     int majorVersion;
 199     /** The minor version number of the class file being read. */
 200     int minorVersion;
 201 
 202     /** UTF-8 validation level */
 203     Convert.Validation utf8validation;
 204 
 205     /** A table to hold the constant pool indices for method parameter
 206      * names, as given in LocalVariableTable attributes.
 207      */
 208     int[] parameterNameIndicesLvt;
 209 
 210     /**
 211      * A table to hold the constant pool indices for method parameter
 212      * names, as given in the MethodParameters attribute.
 213      */
 214     int[] parameterNameIndicesMp;
 215 
 216     /**
 217      * A table to hold the access flags of the method parameters.
 218      */
 219     int[] parameterAccessFlags;
 220 
 221     /**
 222      * A table to hold the access flags of the method parameters,
 223      * for all parameters including synthetic and mandated ones.
 224      */
 225     int[] allParameterAccessFlags;
 226 
 227     /**
 228      * A table to hold annotations for method parameters.
 229      */
 230     ParameterAnnotations[] parameterAnnotations;
 231 
 232     /**
 233      * A holder for parameter annotations.
 234      */
 235     static class ParameterAnnotations {
 236         List<CompoundAnnotationProxy> proxies;
 237 
 238         void add(List<CompoundAnnotationProxy> newAnnotations) {
 239             if (proxies == null) {
 240                 proxies = newAnnotations;
 241             } else {
 242                 proxies = proxies.prependList(newAnnotations);
 243             }
 244         }
 245     }
 246 
 247     /**
 248      * The set of attribute names for which warnings have been generated for the current class
 249      */
 250     Set<Name> warnedAttrs = new HashSet<>();
 251 
 252     /**
 253      * The prototype @Target Attribute.Compound if this class is an annotation annotated with
 254      * {@code @Target}
 255      */
 256     CompoundAnnotationProxy target;
 257 
 258     /**
 259      * The prototype @Repeatable Attribute.Compound if this class is an annotation annotated with
 260      * {@code @Repeatable}
 261      */
 262     CompoundAnnotationProxy repeatable;
 263 
 264     /** Get the ClassReader instance for this invocation. */
 265     public static ClassReader instance(Context context) {
 266         ClassReader instance = context.get(classReaderKey);
 267         if (instance == null)
 268             instance = new ClassReader(context);
 269         return instance;
 270     }
 271 
 272     /** Construct a new class reader. */
 273     @SuppressWarnings("this-escape")
 274     protected ClassReader(Context context) {
 275         context.put(classReaderKey, this);
 276         annotate = Annotate.instance(context);
 277         names = Names.instance(context);
 278         syms = Symtab.instance(context);
 279         types = Types.instance(context);
 280         fileManager = context.get(JavaFileManager.class);
 281         if (fileManager == null)
 282             throw new AssertionError("FileManager initialization error");
 283         diagFactory = JCDiagnostic.Factory.instance(context);
 284         dcfh = DeferredCompletionFailureHandler.instance(context);
 285 
 286         log = Log.instance(context);
 287 
 288         Options options = Options.instance(context);
 289         verbose         = options.isSet(Option.VERBOSE);
 290 
 291         Source source = Source.instance(context);
 292         preview = Preview.instance(context);
 293         allowModules     = Feature.MODULES.allowedInSource(source);
 294         allowRecords = Feature.RECORDS.allowedInSource(source);
 295         allowSealedTypes = Feature.SEALED_CLASSES.allowedInSource(source);
 296         warnOnIllegalUtf8 = Feature.WARN_ON_ILLEGAL_UTF8.allowedInSource(source);
 297 
 298         saveParameterNames = options.isSet(PARAMETERS);
 299 
 300         profile = Profile.instance(context);
 301 
 302         typevars = WriteableScope.create(syms.noSymbol);
 303 
 304         lintClassfile = Lint.instance(context).isEnabled(LintCategory.CLASSFILE);
 305 
 306         initAttributeReaders();
 307     }
 308 
 309     /** Add member to class unless it is synthetic.
 310      */
 311     private void enterMember(ClassSymbol c, Symbol sym) {
 312         // Synthetic members are not entered -- reason lost to history (optimization?).
 313         // Lambda methods must be entered because they may have inner classes (which reference them)
 314         if ((sym.flags_field & (SYNTHETIC|BRIDGE)) != SYNTHETIC || sym.name.startsWith(names.lambda))
 315             c.members_field.enter(sym);
 316     }
 317 
 318 /* **********************************************************************
 319  * Error Diagnoses
 320  ***********************************************************************/
 321 
 322     public ClassFinder.BadClassFile badClassFile(String key, Object... args) {
 323         return badClassFile(diagFactory.fragment(key, args));
 324     }
 325 
 326     public ClassFinder.BadClassFile badClassFile(Fragment fragment) {
 327         return badClassFile(diagFactory.fragment(fragment));
 328     }
 329 
 330     public ClassFinder.BadClassFile badClassFile(JCDiagnostic diagnostic) {
 331         return new ClassFinder.BadClassFile (
 332             currentOwner.enclClass(),
 333             currentClassFile,
 334             diagnostic,
 335             diagFactory,
 336             dcfh);
 337     }
 338 
 339     public ClassFinder.BadEnclosingMethodAttr badEnclosingMethod(Symbol sym) {
 340         return new ClassFinder.BadEnclosingMethodAttr (
 341             currentOwner.enclClass(),
 342             currentClassFile,
 343             diagFactory.fragment(Fragments.BadEnclosingMethod(sym)),
 344             diagFactory,
 345             dcfh);
 346     }
 347 
 348 /* **********************************************************************
 349  * Buffer Access
 350  ***********************************************************************/
 351 
 352     /** Read a character.
 353      */
 354     char nextChar() {
 355         char res;
 356         try {
 357             res = buf.getChar(bp);
 358         } catch (UnderflowException e) {
 359             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 360         }
 361         bp += 2;
 362         return res;
 363     }
 364 
 365     /** Read a byte.
 366      */
 367     int nextByte() {
 368         try {
 369             return buf.getByte(bp++) & 0xFF;
 370         } catch (UnderflowException e) {
 371             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 372         }
 373     }
 374 
 375     /** Read an integer.
 376      */
 377     int nextInt() {
 378         int res;
 379         try {
 380             res = buf.getInt(bp);
 381         } catch (UnderflowException e) {
 382             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 383         }
 384         bp += 4;
 385         return res;
 386     }
 387 
 388 /* **********************************************************************
 389  * Constant Pool Access
 390  ***********************************************************************/
 391 
 392     /** Read module_flags.
 393      */
 394     Set<ModuleFlags> readModuleFlags(int flags) {
 395         Set<ModuleFlags> set = EnumSet.noneOf(ModuleFlags.class);
 396         for (ModuleFlags f : ModuleFlags.values()) {
 397             if ((flags & f.value) != 0)
 398                 set.add(f);
 399         }
 400         return set;
 401     }
 402 
 403     /** Read resolution_flags.
 404      */
 405     Set<ModuleResolutionFlags> readModuleResolutionFlags(int flags) {
 406         Set<ModuleResolutionFlags> set = EnumSet.noneOf(ModuleResolutionFlags.class);
 407         for (ModuleResolutionFlags f : ModuleResolutionFlags.values()) {
 408             if ((flags & f.value) != 0)
 409                 set.add(f);
 410         }
 411         return set;
 412     }
 413 
 414     /** Read exports_flags.
 415      */
 416     Set<ExportsFlag> readExportsFlags(int flags) {
 417         Set<ExportsFlag> set = EnumSet.noneOf(ExportsFlag.class);
 418         for (ExportsFlag f: ExportsFlag.values()) {
 419             if ((flags & f.value) != 0)
 420                 set.add(f);
 421         }
 422         return set;
 423     }
 424 
 425     /** Read opens_flags.
 426      */
 427     Set<OpensFlag> readOpensFlags(int flags) {
 428         Set<OpensFlag> set = EnumSet.noneOf(OpensFlag.class);
 429         for (OpensFlag f: OpensFlag.values()) {
 430             if ((flags & f.value) != 0)
 431                 set.add(f);
 432         }
 433         return set;
 434     }
 435 
 436     /** Read requires_flags.
 437      */
 438     Set<RequiresFlag> readRequiresFlags(int flags) {
 439         Set<RequiresFlag> set = EnumSet.noneOf(RequiresFlag.class);
 440         for (RequiresFlag f: RequiresFlag.values()) {
 441             if ((flags & f.value) != 0)
 442                 set.add(f);
 443         }
 444         return set;
 445     }
 446 
 447 /* **********************************************************************
 448  * Reading Types
 449  ***********************************************************************/
 450 
 451     /** The unread portion of the currently read type is
 452      *  signature[sigp..siglimit-1].
 453      */
 454     byte[] signature;
 455     int sigp;
 456     int siglimit;
 457     boolean sigEnterPhase = false;
 458 
 459     /** Convert signature to type, where signature is a byte array segment.
 460      */
 461     Type sigToType(byte[] sig, int offset, int len) {
 462         signature = sig;
 463         sigp = offset;
 464         siglimit = offset + len;
 465         return sigToType();
 466     }
 467 
 468     /** Convert signature to type, where signature is implicit.
 469      */
 470     Type sigToType() {
 471         switch ((char) signature[sigp]) {
 472         case 'T':
 473             sigp++;
 474             int start = sigp;
 475             while (signature[sigp] != ';') sigp++;
 476             sigp++;
 477             return sigEnterPhase
 478                 ? Type.noType
 479                 : findTypeVar(readName(signature, start, sigp - 1 - start));
 480         case '+': {
 481             sigp++;
 482             Type t = sigToType();
 483             return new WildcardType(t, BoundKind.EXTENDS, syms.boundClass);
 484         }
 485         case '*':
 486             sigp++;
 487             return new WildcardType(syms.objectType, BoundKind.UNBOUND,
 488                                     syms.boundClass);
 489         case '-': {
 490             sigp++;
 491             Type t = sigToType();
 492             return new WildcardType(t, BoundKind.SUPER, syms.boundClass);
 493         }
 494         case 'B':
 495             sigp++;
 496             return syms.byteType;
 497         case 'C':
 498             sigp++;
 499             return syms.charType;
 500         case 'D':
 501             sigp++;
 502             return syms.doubleType;
 503         case 'F':
 504             sigp++;
 505             return syms.floatType;
 506         case 'I':
 507             sigp++;
 508             return syms.intType;
 509         case 'J':
 510             sigp++;
 511             return syms.longType;
 512         case 'L':
 513             {
 514                 // int oldsigp = sigp;
 515                 Type t = classSigToType();
 516                 if (sigp < siglimit && signature[sigp] == '.')
 517                     throw badClassFile("deprecated inner class signature syntax " +
 518                                        "(please recompile from source)");
 519                 /*
 520                 System.err.println(" decoded " +
 521                                    new String(signature, oldsigp, sigp-oldsigp) +
 522                                    " => " + t + " outer " + t.outer());
 523                 */
 524                 return t;
 525             }
 526         case 'S':
 527             sigp++;
 528             return syms.shortType;
 529         case 'V':
 530             sigp++;
 531             return syms.voidType;
 532         case 'Z':
 533             sigp++;
 534             return syms.booleanType;
 535         case '[':
 536             sigp++;
 537             return new ArrayType(sigToType(), syms.arrayClass);
 538         case '(':
 539             sigp++;
 540             List<Type> argtypes = sigToTypes(')');
 541             Type restype = sigToType();
 542             List<Type> thrown = List.nil();
 543             while (sigp < siglimit && signature[sigp] == '^') {
 544                 sigp++;
 545                 thrown = thrown.prepend(sigToType());
 546             }
 547             // if there is a typevar in the throws clause we should state it.
 548             for (List<Type> l = thrown; l.nonEmpty(); l = l.tail) {
 549                 if (l.head.hasTag(TYPEVAR)) {
 550                     l.head.tsym.flags_field |= THROWS;
 551                 }
 552             }
 553             return new MethodType(argtypes,
 554                                   restype,
 555                                   thrown.reverse(),
 556                                   syms.methodClass);
 557         case '<':
 558             typevars = typevars.dup(currentOwner);
 559             Type poly = new ForAll(sigToTypeParams(), sigToType());
 560             typevars = typevars.leave();
 561             return poly;
 562         default:
 563             throw badClassFile("bad.signature", quoteBadSignature());
 564         }
 565     }
 566 
 567     byte[] signatureBuffer = new byte[0];
 568     int sbp = 0;
 569     /** Convert class signature to type, where signature is implicit.
 570      */
 571     Type classSigToType() {
 572         if (signature[sigp] != 'L')
 573             throw badClassFile("bad.class.signature", quoteBadSignature());
 574         sigp++;
 575         Type outer = Type.noType;
 576         int startSbp = sbp;
 577 
 578         while (true) {
 579             final byte c = signature[sigp++];
 580             switch (c) {
 581 
 582             case ';': {         // end
 583                 ClassSymbol t = enterClass(readName(signatureBuffer,
 584                                                          startSbp,
 585                                                          sbp - startSbp));
 586 
 587                 try {
 588                     return (outer == Type.noType) ?
 589                             t.erasure(types) :
 590                         new ClassType(outer, List.nil(), t);
 591                 } finally {
 592                     sbp = startSbp;
 593                 }
 594             }
 595 
 596             case '<':           // generic arguments
 597                 ClassSymbol t = enterClass(readName(signatureBuffer,
 598                                                          startSbp,
 599                                                          sbp - startSbp));
 600                 List<Type> actuals = sigToTypes('>');
 601                 List<Type> formals = ((ClassType)t.type.tsym.type).typarams_field;
 602                 if (formals != null) {
 603                     if (actuals.isEmpty())
 604                         actuals = formals;
 605                 }
 606                 /* actualsCp is final as it will be captured by the inner class below. We could avoid defining
 607                  * this additional local variable and depend on field ClassType::typarams_field which `actuals` is
 608                  * assigned to but then we would have a dependendy on the internal representation of ClassType which
 609                  * could change in the future
 610                  */
 611                 final List<Type> actualsCp = actuals;
 612                 outer = new ClassType(outer, actuals, t) {
 613                         boolean completed = false;
 614                         boolean typeArgsSet = false;
 615                         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 616                         public Type getEnclosingType() {
 617                             if (!completed) {
 618                                 completed = true;
 619                                 tsym.apiComplete();
 620                                 Type enclosingType = tsym.type.getEnclosingType();
 621                                 if (enclosingType != Type.noType) {
 622                                     List<Type> typeArgs =
 623                                         super.getEnclosingType().allparams();
 624                                     List<Type> typeParams =
 625                                         enclosingType.allparams();
 626                                     if (typeParams.length() != typeArgs.length()) {
 627                                         // no "rare" types
 628                                         super.setEnclosingType(types.erasure(enclosingType));
 629                                     } else {
 630                                         super.setEnclosingType(types.subst(enclosingType,
 631                                                                            typeParams,
 632                                                                            typeArgs));
 633                                     }
 634                                 } else {
 635                                     super.setEnclosingType(Type.noType);
 636                                 }
 637                             }
 638                             return super.getEnclosingType();
 639                         }
 640                         @Override
 641                         public void setEnclosingType(Type outer) {
 642                             throw new UnsupportedOperationException();
 643                         }
 644 
 645                         @Override
 646                         public List<Type> getTypeArguments() {
 647                             if (!typeArgsSet) {
 648                                 typeArgsSet = true;
 649                                 List<Type> formalsCp = ((ClassType)t.type.tsym.type).typarams_field;
 650                                 if (formalsCp != null && !formalsCp.isEmpty()) {
 651                                     if (actualsCp.length() == formalsCp.length()) {
 652                                         List<Type> a = actualsCp;
 653                                         List<Type> f = formalsCp;
 654                                         while (a.nonEmpty()) {
 655                                             a.head = a.head.withTypeVar(f.head);
 656                                             a = a.tail;
 657                                             f = f.tail;
 658                                         }
 659                                     }
 660                                 }
 661                             }
 662                             return super.getTypeArguments();
 663                         }
 664                 };
 665                 switch (signature[sigp++]) {
 666                 case ';':
 667                     if (sigp < siglimit && signature[sigp] == '.') {
 668                         // support old-style GJC signatures
 669                         // The signature produced was
 670                         // Lfoo/Outer<Lfoo/X;>;.Lfoo/Outer$Inner<Lfoo/Y;>;
 671                         // rather than say
 672                         // Lfoo/Outer<Lfoo/X;>.Inner<Lfoo/Y;>;
 673                         // so we skip past ".Lfoo/Outer$"
 674                         sigp += (sbp - startSbp) + // "foo/Outer"
 675                             3;  // ".L" and "$"
 676                         signatureBuffer[sbp++] = (byte)'$';
 677                         break;
 678                     } else {
 679                         sbp = startSbp;
 680                         return outer;
 681                     }
 682                 case '.':
 683                     signatureBuffer[sbp++] = (byte)'$';
 684                     break;
 685                 default:
 686                     throw new AssertionError(signature[sigp-1]);
 687                 }
 688                 continue;
 689 
 690             case '.':
 691                 //we have seen an enclosing non-generic class
 692                 if (outer != Type.noType) {
 693                     t = enterClass(readName(signatureBuffer,
 694                                                  startSbp,
 695                                                  sbp - startSbp));
 696                     outer = new ClassType(outer, List.nil(), t);
 697                 }
 698                 signatureBuffer[sbp++] = (byte)'$';
 699                 continue;
 700             case '/':
 701                 signatureBuffer[sbp++] = (byte)'.';
 702                 continue;
 703             default:
 704                 signatureBuffer[sbp++] = c;
 705                 continue;
 706             }
 707         }
 708     }
 709 
 710     /** Quote a bogus signature for display inside an error message.
 711      */
 712     String quoteBadSignature() {
 713         String sigString;
 714         try {
 715             sigString = Convert.utf2string(signature, sigp, siglimit - sigp, Convert.Validation.NONE);
 716         } catch (InvalidUtfException e) {
 717             throw new AssertionError(e);
 718         }
 719         if (sigString.length() > 32)
 720             sigString = sigString.substring(0, 32) + "...";
 721         return "\"" + sigString + "\"";
 722     }
 723 
 724     /** Convert (implicit) signature to list of types
 725      *  until `terminator' is encountered.
 726      */
 727     List<Type> sigToTypes(char terminator) {
 728         List<Type> head = List.of(null);
 729         List<Type> tail = head;
 730         while (signature[sigp] != terminator)
 731             tail = tail.setTail(List.of(sigToType()));
 732         sigp++;
 733         return head.tail;
 734     }
 735 
 736     /** Convert signature to type parameters, where signature is a byte
 737      *  array segment.
 738      */
 739     List<Type> sigToTypeParams(byte[] sig, int offset, int len) {
 740         signature = sig;
 741         sigp = offset;
 742         siglimit = offset + len;
 743         return sigToTypeParams();
 744     }
 745 
 746     /** Convert signature to type parameters, where signature is implicit.
 747      */
 748     List<Type> sigToTypeParams() {
 749         List<Type> tvars = List.nil();
 750         if (signature[sigp] == '<') {
 751             sigp++;
 752             int start = sigp;
 753             sigEnterPhase = true;
 754             while (signature[sigp] != '>')
 755                 tvars = tvars.prepend(sigToTypeParam());
 756             sigEnterPhase = false;
 757             sigp = start;
 758             while (signature[sigp] != '>')
 759                 sigToTypeParam();
 760             sigp++;
 761         }
 762         return tvars.reverse();
 763     }
 764 
 765     /** Convert (implicit) signature to type parameter.
 766      */
 767     Type sigToTypeParam() {
 768         int start = sigp;
 769         while (signature[sigp] != ':') sigp++;
 770         Name name = readName(signature, start, sigp - start);
 771         TypeVar tvar;
 772         if (sigEnterPhase) {
 773             tvar = new TypeVar(name, currentOwner, syms.botType);
 774             typevars.enter(tvar.tsym);
 775         } else {
 776             tvar = (TypeVar)findTypeVar(name);
 777         }
 778         List<Type> bounds = List.nil();
 779         boolean allInterfaces = false;
 780         if (signature[sigp] == ':' && signature[sigp+1] == ':') {
 781             sigp++;
 782             allInterfaces = true;
 783         }
 784         while (signature[sigp] == ':') {
 785             sigp++;
 786             bounds = bounds.prepend(sigToType());
 787         }
 788         if (!sigEnterPhase) {
 789             types.setBounds(tvar, bounds.reverse(), allInterfaces);
 790         }
 791         return tvar;
 792     }
 793 
 794     /** Find type variable with given name in `typevars' scope.
 795      */
 796     Type findTypeVar(Name name) {
 797         Symbol s = typevars.findFirst(name);
 798         if (s != null) {
 799             return s.type;
 800         } else {
 801             if (readingClassAttr) {
 802                 // While reading the class attribute, the supertypes
 803                 // might refer to a type variable from an enclosing element
 804                 // (method or class).
 805                 // If the type variable is defined in the enclosing class,
 806                 // we can actually find it in
 807                 // currentOwner.owner.type.getTypeArguments()
 808                 // However, until we have read the enclosing method attribute
 809                 // we don't know for sure if this owner is correct.  It could
 810                 // be a method and there is no way to tell before reading the
 811                 // enclosing method attribute.
 812                 TypeVar t = new TypeVar(name, currentOwner, syms.botType);
 813                 missingTypeVariables = missingTypeVariables.prepend(t);
 814                 // System.err.println("Missing type var " + name);
 815                 return t;
 816             }
 817             throw badClassFile("undecl.type.var", name);
 818         }
 819     }
 820 
 821     private Name readName(byte[] buf, int off, int len) {
 822         try {
 823             return names.fromUtf(buf, off, len, utf8validation);
 824         } catch (InvalidUtfException e) {
 825             if (warnOnIllegalUtf8) {
 826                 log.warning(Warnings.InvalidUtf8InClassfile(currentClassFile,
 827                     Fragments.BadUtf8ByteSequenceAt(sigp)));
 828                 return names.fromUtfLax(buf, off, len);
 829             }
 830             throw badClassFile(Fragments.BadUtf8ByteSequenceAt(sigp));
 831         }
 832     }
 833 
 834 /* **********************************************************************
 835  * Reading Attributes
 836  ***********************************************************************/
 837 
 838     protected enum AttributeKind { CLASS, MEMBER }
 839 
 840     protected abstract class AttributeReader {
 841         protected AttributeReader(Name name, ClassFile.Version version, Set<AttributeKind> kinds) {
 842             this.name = name;
 843             this.version = version;
 844             this.kinds = kinds;
 845         }
 846 
 847         protected boolean accepts(AttributeKind kind) {
 848             if (kinds.contains(kind)) {
 849                 if (majorVersion > version.major || (majorVersion == version.major && minorVersion >= version.minor))
 850                     return true;
 851 
 852                 if (lintClassfile && !warnedAttrs.contains(name)) {
 853                     JavaFileObject prev = log.useSource(currentClassFile);
 854                     try {
 855                         log.warning(LintCategory.CLASSFILE, (DiagnosticPosition) null,
 856                                     Warnings.FutureAttr(name, version.major, version.minor, majorVersion, minorVersion));
 857                     } finally {
 858                         log.useSource(prev);
 859                     }
 860                     warnedAttrs.add(name);
 861                 }
 862             }
 863             return false;
 864         }
 865 
 866         protected abstract void read(Symbol sym, int attrLen);
 867 
 868         protected final Name name;
 869         protected final ClassFile.Version version;
 870         protected final Set<AttributeKind> kinds;
 871     }
 872 
 873     protected Set<AttributeKind> CLASS_ATTRIBUTE =
 874             EnumSet.of(AttributeKind.CLASS);
 875     protected Set<AttributeKind> MEMBER_ATTRIBUTE =
 876             EnumSet.of(AttributeKind.MEMBER);
 877     protected Set<AttributeKind> CLASS_OR_MEMBER_ATTRIBUTE =
 878             EnumSet.of(AttributeKind.CLASS, AttributeKind.MEMBER);
 879 
 880     protected Map<Name, AttributeReader> attributeReaders = new HashMap<>();
 881 
 882     private void initAttributeReaders() {
 883         AttributeReader[] readers = {
 884             // v45.3 attributes
 885 
 886             new AttributeReader(names.Code, V45_3, MEMBER_ATTRIBUTE) {
 887                 protected void read(Symbol sym, int attrLen) {
 888                     if (saveParameterNames)
 889                         ((MethodSymbol)sym).code = readCode(sym);
 890                     else
 891                         bp = bp + attrLen;
 892                 }
 893             },
 894 
 895             new AttributeReader(names.ConstantValue, V45_3, MEMBER_ATTRIBUTE) {
 896                 protected void read(Symbol sym, int attrLen) {
 897                     Object v = poolReader.getConstant(nextChar());
 898                     // Ignore ConstantValue attribute if field not final.
 899                     if ((sym.flags() & FINAL) == 0) {
 900                         return;
 901                     }
 902                     VarSymbol var = (VarSymbol) sym;
 903                     switch (var.type.getTag()) {
 904                        case BOOLEAN:
 905                        case BYTE:
 906                        case CHAR:
 907                        case SHORT:
 908                        case INT:
 909                            checkType(var, Integer.class, v);
 910                            break;
 911                        case LONG:
 912                            checkType(var, Long.class, v);
 913                            break;
 914                        case FLOAT:
 915                            checkType(var, Float.class, v);
 916                            break;
 917                        case DOUBLE:
 918                            checkType(var, Double.class, v);
 919                            break;
 920                        case CLASS:
 921                            if (var.type.tsym == syms.stringType.tsym) {
 922                                checkType(var, String.class, v);
 923                            } else {
 924                                throw badClassFile("bad.constant.value.type", var.type);
 925                            }
 926                            break;
 927                        default:
 928                            // ignore ConstantValue attribute if type is not primitive or String
 929                            return;
 930                     }
 931                     if (v instanceof Integer intVal && !var.type.getTag().checkRange(intVal)) {
 932                         throw badClassFile("bad.constant.range", v, var, var.type);
 933                     }
 934                     var.setData(v);
 935                 }
 936 
 937                 void checkType(Symbol var, Class<?> clazz, Object value) {
 938                     if (!clazz.isInstance(value)) {
 939                         throw badClassFile("bad.constant.value", value, var, clazz.getSimpleName());
 940                     }
 941                 }
 942             },
 943 
 944             new AttributeReader(names.Deprecated, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 945                 protected void read(Symbol sym, int attrLen) {
 946                     Symbol s = sym.owner.kind == MDL ? sym.owner : sym;
 947 
 948                     s.flags_field |= DEPRECATED;
 949                 }
 950             },
 951 
 952             new AttributeReader(names.Exceptions, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 953                 protected void read(Symbol sym, int attrLen) {
 954                     int nexceptions = nextChar();
 955                     List<Type> thrown = List.nil();
 956                     for (int j = 0; j < nexceptions; j++)
 957                         thrown = thrown.prepend(poolReader.getClass(nextChar()).type);
 958                     if (sym.type.getThrownTypes().isEmpty())
 959                         sym.type.asMethodType().thrown = thrown.reverse();
 960                 }
 961             },
 962 
 963             new AttributeReader(names.InnerClasses, V45_3, CLASS_ATTRIBUTE) {
 964                 protected void read(Symbol sym, int attrLen) {
 965                     ClassSymbol c = (ClassSymbol) sym;
 966                     if (currentModule.module_info == c) {
 967                         //prevent entering the classes too soon:
 968                         skipInnerClasses();
 969                     } else {
 970                         readInnerClasses(c);
 971                     }
 972                 }
 973             },
 974 
 975             new AttributeReader(names.LocalVariableTable, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 976                 protected void read(Symbol sym, int attrLen) {
 977                     int newbp = bp + attrLen;
 978                     if (saveParameterNames) {
 979                         // Pick up parameter names from the variable table.
 980                         // Parameter names are not explicitly identified as such,
 981                         // but all parameter name entries in the LocalVariableTable
 982                         // have a start_pc of 0.  Therefore, we record the name
 983                         // indices of all slots with a start_pc of zero in the
 984                         // parameterNameIndices array.
 985                         // Note that this implicitly honors the JVMS spec that
 986                         // there may be more than one LocalVariableTable, and that
 987                         // there is no specified ordering for the entries.
 988                         int numEntries = nextChar();
 989                         for (int i = 0; i < numEntries; i++) {
 990                             int start_pc = nextChar();
 991                             int length = nextChar();
 992                             int nameIndex = nextChar();
 993                             int sigIndex = nextChar();
 994                             int register = nextChar();
 995                             if (start_pc == 0) {
 996                                 // ensure array large enough
 997                                 if (register >= parameterNameIndicesLvt.length) {
 998                                     int newSize =
 999                                             Math.max(register + 1, parameterNameIndicesLvt.length + 8);
1000                                     parameterNameIndicesLvt =
1001                                             Arrays.copyOf(parameterNameIndicesLvt, newSize);
1002                                 }
1003                                 parameterNameIndicesLvt[register] = nameIndex;
1004                             }
1005                         }
1006                     }
1007                     bp = newbp;
1008                 }
1009             },
1010 
1011             new AttributeReader(names.SourceFile, V45_3, CLASS_ATTRIBUTE) {
1012                 protected void read(Symbol sym, int attrLen) {
1013                     ClassSymbol c = (ClassSymbol) sym;
1014                     Name n = poolReader.getName(nextChar());
1015                     c.sourcefile = new SourceFileObject(n);
1016                     // If the class is a toplevel class, originating from a Java source file,
1017                     // but the class name does not match the file name, then it is
1018                     // an auxiliary class.
1019                     String sn = n.toString();
1020                     if (c.owner.kind == PCK &&
1021                         sn.endsWith(".java") &&
1022                         !sn.equals(c.name.toString()+".java")) {
1023                         c.flags_field |= AUXILIARY;
1024                     }
1025                 }
1026             },
1027 
1028             new AttributeReader(names.Synthetic, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
1029                 protected void read(Symbol sym, int attrLen) {
1030                     sym.flags_field |= SYNTHETIC;
1031                 }
1032             },
1033 
1034             // standard v49 attributes
1035 
1036             new AttributeReader(names.EnclosingMethod, V49, CLASS_ATTRIBUTE) {
1037                 protected void read(Symbol sym, int attrLen) {
1038                     int newbp = bp + attrLen;
1039                     readEnclosingMethodAttr(sym);
1040                     bp = newbp;
1041                 }
1042             },
1043 
1044             new AttributeReader(names.Signature, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1045                 protected void read(Symbol sym, int attrLen) {
1046                     if (sym.kind == TYP) {
1047                         ClassSymbol c = (ClassSymbol) sym;
1048                         readingClassAttr = true;
1049                         try {
1050                             ClassType ct1 = (ClassType)c.type;
1051                             Assert.check(c == currentOwner);
1052                             ct1.typarams_field = poolReader.getName(nextChar())
1053                                     .map(ClassReader.this::sigToTypeParams);
1054                             ct1.supertype_field = sigToType();
1055                             ListBuffer<Type> is = new ListBuffer<>();
1056                             while (sigp != siglimit) is.append(sigToType());
1057                             ct1.interfaces_field = is.toList();
1058                         } finally {
1059                             readingClassAttr = false;
1060                         }
1061                     } else {
1062                         List<Type> thrown = sym.type.getThrownTypes();
1063                         sym.type = poolReader.getType(nextChar());
1064                         //- System.err.println(" # " + sym.type);
1065                         if (sym.kind == MTH && sym.type.getThrownTypes().isEmpty())
1066                             sym.type.asMethodType().thrown = thrown;
1067 
1068                     }
1069                 }
1070             },
1071 
1072             // v49 annotation attributes
1073 
1074             new AttributeReader(names.AnnotationDefault, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1075                 protected void read(Symbol sym, int attrLen) {
1076                     attachAnnotationDefault(sym);
1077                 }
1078             },
1079 
1080             new AttributeReader(names.RuntimeInvisibleAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1081                 protected void read(Symbol sym, int attrLen) {
1082                     attachAnnotations(sym);
1083                 }
1084             },
1085 
1086             new AttributeReader(names.RuntimeInvisibleParameterAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1087                 protected void read(Symbol sym, int attrLen) {
1088                     readParameterAnnotations(sym);
1089                 }
1090             },
1091 
1092             new AttributeReader(names.RuntimeVisibleAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1093                 protected void read(Symbol sym, int attrLen) {
1094                     attachAnnotations(sym);
1095                 }
1096             },
1097 
1098             new AttributeReader(names.RuntimeVisibleParameterAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1099                 protected void read(Symbol sym, int attrLen) {
1100                     readParameterAnnotations(sym);
1101                 }
1102             },
1103 
1104             // additional "legacy" v49 attributes, superseded by flags
1105 
1106             new AttributeReader(names.Annotation, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1107                 protected void read(Symbol sym, int attrLen) {
1108                     sym.flags_field |= ANNOTATION;
1109                 }
1110             },
1111 
1112             new AttributeReader(names.Bridge, V49, MEMBER_ATTRIBUTE) {
1113                 protected void read(Symbol sym, int attrLen) {
1114                     sym.flags_field |= BRIDGE;
1115                 }
1116             },
1117 
1118             new AttributeReader(names.Enum, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1119                 protected void read(Symbol sym, int attrLen) {
1120                     sym.flags_field |= ENUM;
1121                 }
1122             },
1123 
1124             new AttributeReader(names.Varargs, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1125                 protected void read(Symbol sym, int attrLen) {
1126                     sym.flags_field |= VARARGS;
1127                 }
1128             },
1129 
1130             new AttributeReader(names.RuntimeVisibleTypeAnnotations, V52, CLASS_OR_MEMBER_ATTRIBUTE) {
1131                 protected void read(Symbol sym, int attrLen) {
1132                     attachTypeAnnotations(sym);
1133                 }
1134             },
1135 
1136             new AttributeReader(names.RuntimeInvisibleTypeAnnotations, V52, CLASS_OR_MEMBER_ATTRIBUTE) {
1137                 protected void read(Symbol sym, int attrLen) {
1138                     attachTypeAnnotations(sym);
1139                 }
1140             },
1141 
1142             // The following attributes for a Code attribute are not currently handled
1143             // StackMapTable
1144             // SourceDebugExtension
1145             // LineNumberTable
1146             // LocalVariableTypeTable
1147 
1148             // standard v52 attributes
1149 
1150             new AttributeReader(names.MethodParameters, V52, MEMBER_ATTRIBUTE) {
1151                 protected void read(Symbol sym, int attrlen) {
1152                     int newbp = bp + attrlen;
1153                     if (saveParameterNames) {
1154                         int numEntries = nextByte();
1155                         allParameterAccessFlags = new int[numEntries];
1156                         parameterNameIndicesMp = new int[numEntries];
1157                         parameterAccessFlags = new int[numEntries];
1158                         int allParamIndex = 0;
1159                         int index = 0;
1160                         for (int i = 0; i < numEntries; i++) {
1161                             int nameIndex = nextChar();
1162                             int flags = nextChar();
1163                             allParameterAccessFlags[allParamIndex++] = flags;
1164                             if ((flags & (Flags.MANDATED | Flags.SYNTHETIC)) != 0) {
1165                                 continue;
1166                             }
1167                             parameterNameIndicesMp[index] = nameIndex;
1168                             parameterAccessFlags[index] = flags;
1169                             index++;
1170                         }
1171                     }
1172                     bp = newbp;
1173                 }
1174             },
1175 
1176             // standard v53 attributes
1177 
1178             new AttributeReader(names.Module, V53, CLASS_ATTRIBUTE) {
1179                 @Override
1180                 protected boolean accepts(AttributeKind kind) {
1181                     return super.accepts(kind) && allowModules;
1182                 }
1183                 protected void read(Symbol sym, int attrLen) {
1184                     if (sym.kind == TYP && sym.owner.kind == MDL) {
1185                         ModuleSymbol msym = (ModuleSymbol) sym.owner;
1186                         ListBuffer<Directive> directives = new ListBuffer<>();
1187 
1188                         Name moduleName = poolReader.peekModuleName(nextChar(), ClassReader.this::readName);
1189                         if (currentModule.name != moduleName) {
1190                             throw badClassFile("module.name.mismatch", moduleName, currentModule.name);
1191                         }
1192 
1193                         Set<ModuleFlags> moduleFlags = readModuleFlags(nextChar());
1194                         msym.flags.addAll(moduleFlags);
1195                         msym.version = optPoolEntry(nextChar(), poolReader::getName, null);
1196 
1197                         ListBuffer<RequiresDirective> requires = new ListBuffer<>();
1198                         int nrequires = nextChar();
1199                         for (int i = 0; i < nrequires; i++) {
1200                             ModuleSymbol rsym = poolReader.getModule(nextChar());
1201                             Set<RequiresFlag> flags = readRequiresFlags(nextChar());
1202                             if (rsym == syms.java_base && majorVersion >= V54.major) {
1203                                 if (flags.contains(RequiresFlag.TRANSITIVE)) {
1204                                     throw badClassFile("bad.requires.flag", RequiresFlag.TRANSITIVE);
1205                                 }
1206                                 if (flags.contains(RequiresFlag.STATIC_PHASE)) {
1207                                     throw badClassFile("bad.requires.flag", RequiresFlag.STATIC_PHASE);
1208                                 }
1209                             }
1210                             nextChar(); // skip compiled version
1211                             requires.add(new RequiresDirective(rsym, flags));
1212                         }
1213                         msym.requires = requires.toList();
1214                         directives.addAll(msym.requires);
1215 
1216                         ListBuffer<ExportsDirective> exports = new ListBuffer<>();
1217                         int nexports = nextChar();
1218                         for (int i = 0; i < nexports; i++) {
1219                             PackageSymbol p = poolReader.getPackage(nextChar());
1220                             Set<ExportsFlag> flags = readExportsFlags(nextChar());
1221                             int nto = nextChar();
1222                             List<ModuleSymbol> to;
1223                             if (nto == 0) {
1224                                 to = null;
1225                             } else {
1226                                 ListBuffer<ModuleSymbol> lb = new ListBuffer<>();
1227                                 for (int t = 0; t < nto; t++)
1228                                     lb.append(poolReader.getModule(nextChar()));
1229                                 to = lb.toList();
1230                             }
1231                             exports.add(new ExportsDirective(p, to, flags));
1232                         }
1233                         msym.exports = exports.toList();
1234                         directives.addAll(msym.exports);
1235                         ListBuffer<OpensDirective> opens = new ListBuffer<>();
1236                         int nopens = nextChar();
1237                         if (nopens != 0 && msym.flags.contains(ModuleFlags.OPEN)) {
1238                             throw badClassFile("module.non.zero.opens", currentModule.name);
1239                         }
1240                         for (int i = 0; i < nopens; i++) {
1241                             PackageSymbol p = poolReader.getPackage(nextChar());
1242                             Set<OpensFlag> flags = readOpensFlags(nextChar());
1243                             int nto = nextChar();
1244                             List<ModuleSymbol> to;
1245                             if (nto == 0) {
1246                                 to = null;
1247                             } else {
1248                                 ListBuffer<ModuleSymbol> lb = new ListBuffer<>();
1249                                 for (int t = 0; t < nto; t++)
1250                                     lb.append(poolReader.getModule(nextChar()));
1251                                 to = lb.toList();
1252                             }
1253                             opens.add(new OpensDirective(p, to, flags));
1254                         }
1255                         msym.opens = opens.toList();
1256                         directives.addAll(msym.opens);
1257 
1258                         msym.directives = directives.toList();
1259 
1260                         ListBuffer<InterimUsesDirective> uses = new ListBuffer<>();
1261                         int nuses = nextChar();
1262                         for (int i = 0; i < nuses; i++) {
1263                             Name srvc = poolReader.peekClassName(nextChar(), this::classNameMapper);
1264                             uses.add(new InterimUsesDirective(srvc));
1265                         }
1266                         interimUses = uses.toList();
1267 
1268                         ListBuffer<InterimProvidesDirective> provides = new ListBuffer<>();
1269                         int nprovides = nextChar();
1270                         for (int p = 0; p < nprovides; p++) {
1271                             Name srvc = poolReader.peekClassName(nextChar(), this::classNameMapper);
1272                             int nimpls = nextChar();
1273                             ListBuffer<Name> impls = new ListBuffer<>();
1274                             for (int i = 0; i < nimpls; i++) {
1275                                 impls.append(poolReader.peekClassName(nextChar(), this::classNameMapper));
1276                             provides.add(new InterimProvidesDirective(srvc, impls.toList()));
1277                             }
1278                         }
1279                         interimProvides = provides.toList();
1280                     }
1281                 }
1282 
1283                 private Name classNameMapper(byte[] arr, int offset, int length) throws InvalidUtfException {
1284                     byte[] buf = ClassFile.internalize(arr, offset, length);
1285                     try {
1286                         return names.fromUtf(buf, 0, buf.length, utf8validation);
1287                     } catch (InvalidUtfException e) {
1288                         if (warnOnIllegalUtf8) {
1289                             log.warning(Warnings.InvalidUtf8InClassfile(currentClassFile,
1290                                 Fragments.BadUtf8ByteSequenceAt(e.getOffset())));
1291                             return names.fromUtfLax(buf, 0, buf.length);
1292                         }
1293                         throw e;
1294                     }
1295                 }
1296             },
1297 
1298             new AttributeReader(names.ModuleResolution, V53, CLASS_ATTRIBUTE) {
1299                 @Override
1300                 protected boolean accepts(AttributeKind kind) {
1301                     return super.accepts(kind) && allowModules;
1302                 }
1303                 protected void read(Symbol sym, int attrLen) {
1304                     if (sym.kind == TYP && sym.owner.kind == MDL) {
1305                         ModuleSymbol msym = (ModuleSymbol) sym.owner;
1306                         msym.resolutionFlags.addAll(readModuleResolutionFlags(nextChar()));
1307                     }
1308                 }
1309             },
1310 
1311             new AttributeReader(names.Record, V58, CLASS_ATTRIBUTE) {
1312                 @Override
1313                 protected boolean accepts(AttributeKind kind) {
1314                     return super.accepts(kind) && allowRecords;
1315                 }
1316                 protected void read(Symbol sym, int attrLen) {
1317                     if (sym.kind == TYP) {
1318                         sym.flags_field |= RECORD;
1319                     }
1320                     int componentCount = nextChar();
1321                     ListBuffer<RecordComponent> components = new ListBuffer<>();
1322                     for (int i = 0; i < componentCount; i++) {
1323                         Name name = poolReader.getName(nextChar());
1324                         Type type = poolReader.getType(nextChar());
1325                         RecordComponent c = new RecordComponent(name, type, sym);
1326                         readAttrs(c, AttributeKind.MEMBER);
1327                         components.add(c);
1328                     }
1329                     ((ClassSymbol) sym).setRecordComponents(components.toList());
1330                 }
1331             },
1332             new AttributeReader(names.PermittedSubclasses, V59, CLASS_ATTRIBUTE) {
1333                 @Override
1334                 protected boolean accepts(AttributeKind kind) {
1335                     return super.accepts(kind) && allowSealedTypes;
1336                 }
1337                 protected void read(Symbol sym, int attrLen) {
1338                     if (sym.kind == TYP) {
1339                         ListBuffer<Symbol> subtypes = new ListBuffer<>();
1340                         int numberOfPermittedSubtypes = nextChar();
1341                         for (int i = 0; i < numberOfPermittedSubtypes; i++) {
1342                             subtypes.add(poolReader.getClass(nextChar()));
1343                         }
1344                         ((ClassSymbol)sym).setPermittedSubclasses(subtypes.toList());
1345                     }
1346                 }
1347             },
1348         };
1349 
1350         for (AttributeReader r: readers)
1351             attributeReaders.put(r.name, r);
1352     }
1353 
1354     protected void readEnclosingMethodAttr(Symbol sym) {
1355         // sym is a nested class with an "Enclosing Method" attribute
1356         // remove sym from it's current owners scope and place it in
1357         // the scope specified by the attribute
1358         sym.owner.members().remove(sym);
1359         ClassSymbol self = (ClassSymbol)sym;
1360         ClassSymbol c = poolReader.getClass(nextChar());
1361         NameAndType nt = optPoolEntry(nextChar(), poolReader::getNameAndType, null);
1362 
1363         if (c.members_field == null || c.kind != TYP)
1364             throw badClassFile("bad.enclosing.class", self, c);
1365 
1366         MethodSymbol m = findMethod(nt, c.members_field, self.flags());
1367         if (nt != null && m == null)
1368             throw badEnclosingMethod(self);
1369 
1370         self.name = simpleBinaryName(self.flatname, c.flatname) ;
1371         self.owner = m != null ? m : c;
1372         if (self.name.isEmpty())
1373             self.fullname = names.empty;
1374         else
1375             self.fullname = ClassSymbol.formFullName(self.name, self.owner);
1376 
1377         if (m != null) {
1378             ((ClassType)sym.type).setEnclosingType(m.type);
1379         } else if ((self.flags_field & STATIC) == 0) {
1380             ((ClassType)sym.type).setEnclosingType(c.type);
1381         } else {
1382             ((ClassType)sym.type).setEnclosingType(Type.noType);
1383         }
1384         enterTypevars(self, self.type);
1385         if (!missingTypeVariables.isEmpty()) {
1386             ListBuffer<Type> typeVars =  new ListBuffer<>();
1387             for (Type typevar : missingTypeVariables) {
1388                 typeVars.append(findTypeVar(typevar.tsym.name));
1389             }
1390             foundTypeVariables = typeVars.toList();
1391         } else {
1392             foundTypeVariables = List.nil();
1393         }
1394     }
1395 
1396     // See java.lang.Class
1397     private Name simpleBinaryName(Name self, Name enclosing) {
1398         if (!self.startsWith(enclosing)) {
1399             throw badClassFile("bad.enclosing.method", self);
1400         }
1401 
1402         String simpleBinaryName = self.toString().substring(enclosing.toString().length());
1403         if (simpleBinaryName.length() < 1 || simpleBinaryName.charAt(0) != '$')
1404             throw badClassFile("bad.enclosing.method", self);
1405         int index = 1;
1406         while (index < simpleBinaryName.length() &&
1407                isAsciiDigit(simpleBinaryName.charAt(index)))
1408             index++;
1409         return names.fromString(simpleBinaryName.substring(index));
1410     }
1411 
1412     private MethodSymbol findMethod(NameAndType nt, Scope scope, long flags) {
1413         if (nt == null)
1414             return null;
1415 
1416         MethodType type = nt.type.asMethodType();
1417 
1418         for (Symbol sym : scope.getSymbolsByName(nt.name)) {
1419             if (sym.kind == MTH && isSameBinaryType(sym.type.asMethodType(), type))
1420                 return (MethodSymbol)sym;
1421         }
1422 
1423         if (nt.name != names.init)
1424             // not a constructor
1425             return null;
1426         if ((flags & INTERFACE) != 0)
1427             // no enclosing instance
1428             return null;
1429         if (nt.type.getParameterTypes().isEmpty())
1430             // no parameters
1431             return null;
1432 
1433         // A constructor of an inner class.
1434         // Remove the first argument (the enclosing instance)
1435         nt = new NameAndType(nt.name, new MethodType(nt.type.getParameterTypes().tail,
1436                                  nt.type.getReturnType(),
1437                                  nt.type.getThrownTypes(),
1438                                  syms.methodClass));
1439         // Try searching again
1440         return findMethod(nt, scope, flags);
1441     }
1442 
1443     /** Similar to Types.isSameType but avoids completion */
1444     private boolean isSameBinaryType(MethodType mt1, MethodType mt2) {
1445         List<Type> types1 = types.erasure(mt1.getParameterTypes())
1446             .prepend(types.erasure(mt1.getReturnType()));
1447         List<Type> types2 = mt2.getParameterTypes().prepend(mt2.getReturnType());
1448         while (!types1.isEmpty() && !types2.isEmpty()) {
1449             if (types1.head.tsym != types2.head.tsym)
1450                 return false;
1451             types1 = types1.tail;
1452             types2 = types2.tail;
1453         }
1454         return types1.isEmpty() && types2.isEmpty();
1455     }
1456 
1457     /**
1458      * Character.isDigit answers <tt>true</tt> to some non-ascii
1459      * digits.  This one does not.  <b>copied from java.lang.Class</b>
1460      */
1461     private static boolean isAsciiDigit(char c) {
1462         return '0' <= c && c <= '9';
1463     }
1464 
1465     /** Read member attributes.
1466      */
1467     void readMemberAttrs(Symbol sym) {
1468         readAttrs(sym, AttributeKind.MEMBER);
1469     }
1470 
1471     void readAttrs(Symbol sym, AttributeKind kind) {
1472         char ac = nextChar();
1473         for (int i = 0; i < ac; i++) {
1474             Name attrName = poolReader.getName(nextChar());
1475             int attrLen = nextInt();
1476             AttributeReader r = attributeReaders.get(attrName);
1477             if (r != null && r.accepts(kind))
1478                 r.read(sym, attrLen);
1479             else  {
1480                 bp = bp + attrLen;
1481             }
1482         }
1483     }
1484 
1485     private boolean readingClassAttr = false;
1486     private List<Type> missingTypeVariables = List.nil();
1487     private List<Type> foundTypeVariables = List.nil();
1488 
1489     /** Read class attributes.
1490      */
1491     void readClassAttrs(ClassSymbol c) {
1492         readAttrs(c, AttributeKind.CLASS);
1493     }
1494 
1495     /** Read code block.
1496      */
1497     Code readCode(Symbol owner) {
1498         nextChar(); // max_stack
1499         nextChar(); // max_locals
1500         final int  code_length = nextInt();
1501         bp += code_length;
1502         final char exception_table_length = nextChar();
1503         bp += exception_table_length * 8;
1504         readMemberAttrs(owner);
1505         return null;
1506     }
1507 
1508 /* **********************************************************************
1509  * Reading Java-language annotations
1510  ***********************************************************************/
1511 
1512     /**
1513      * Save annotations.
1514      */
1515     List<CompoundAnnotationProxy> readAnnotations() {
1516         int numAttributes = nextChar();
1517         ListBuffer<CompoundAnnotationProxy> annotations = new ListBuffer<>();
1518         for (int i = 0; i < numAttributes; i++) {
1519             annotations.append(readCompoundAnnotation());
1520         }
1521         return annotations.toList();
1522     }
1523 
1524     /** Attach annotations.
1525      */
1526     void attachAnnotations(final Symbol sym) {
1527         attachAnnotations(sym, readAnnotations());
1528     }
1529 
1530     /**
1531      * Attach annotations.
1532      */
1533     void attachAnnotations(final Symbol sym, List<CompoundAnnotationProxy> annotations) {
1534         if (annotations.isEmpty()) {
1535             return;
1536         }
1537         ListBuffer<CompoundAnnotationProxy> proxies = new ListBuffer<>();
1538         for (CompoundAnnotationProxy proxy : annotations) {
1539             if (proxy.type.tsym.flatName() == syms.proprietaryType.tsym.flatName())
1540                 sym.flags_field |= PROPRIETARY;
1541             else if (proxy.type.tsym.flatName() == syms.profileType.tsym.flatName()) {
1542                 if (profile != Profile.DEFAULT) {
1543                     for (Pair<Name, Attribute> v : proxy.values) {
1544                         if (v.fst == names.value && v.snd instanceof Attribute.Constant constant) {
1545                             if (constant.type == syms.intType && ((Integer) constant.value) > profile.value) {
1546                                 sym.flags_field |= NOT_IN_PROFILE;
1547                             }
1548                         }
1549                     }
1550                 }
1551             } else if (proxy.type.tsym.flatName() == syms.previewFeatureInternalType.tsym.flatName()) {
1552                 sym.flags_field |= PREVIEW_API;
1553                 setFlagIfAttributeTrue(proxy, sym, names.reflective, PREVIEW_REFLECTIVE);
1554             } else if (proxy.type.tsym.flatName() == syms.valueBasedInternalType.tsym.flatName()) {
1555                 Assert.check(sym.kind == TYP);
1556                 sym.flags_field |= VALUE_BASED;
1557             } else if (proxy.type.tsym.flatName() == syms.restrictedInternalType.tsym.flatName()) {
1558                 Assert.check(sym.kind == MTH);
1559                 sym.flags_field |= RESTRICTED;
1560             } else {
1561                 if (proxy.type.tsym == syms.annotationTargetType.tsym) {
1562                     target = proxy;
1563                 } else if (proxy.type.tsym == syms.repeatableType.tsym) {
1564                     repeatable = proxy;
1565                 } else if (proxy.type.tsym == syms.deprecatedType.tsym) {
1566                     sym.flags_field |= (DEPRECATED | DEPRECATED_ANNOTATION);
1567                     setFlagIfAttributeTrue(proxy, sym, names.forRemoval, DEPRECATED_REMOVAL);
1568                 }  else if (proxy.type.tsym == syms.previewFeatureType.tsym) {
1569                     sym.flags_field |= PREVIEW_API;
1570                     setFlagIfAttributeTrue(proxy, sym, names.reflective, PREVIEW_REFLECTIVE);
1571                 }  else if (proxy.type.tsym == syms.valueBasedType.tsym && sym.kind == TYP) {
1572                     sym.flags_field |= VALUE_BASED;
1573                 }  else if (proxy.type.tsym == syms.restrictedType.tsym) {
1574                     Assert.check(sym.kind == MTH);
1575                     sym.flags_field |= RESTRICTED;
1576                 }
1577                 proxies.append(proxy);
1578             }
1579         }
1580         annotate.normal(new AnnotationCompleter(sym, proxies.toList()));
1581     }
1582     //where:
1583         private void setFlagIfAttributeTrue(CompoundAnnotationProxy proxy, Symbol sym, Name attribute, long flag) {
1584             for (Pair<Name, Attribute> v : proxy.values) {
1585                 if (v.fst == attribute && v.snd instanceof Attribute.Constant constant) {
1586                     if (constant.type == syms.booleanType && ((Integer) constant.value) != 0) {
1587                         sym.flags_field |= flag;
1588                     }
1589                 }
1590             }
1591         }
1592 
1593     /** Read parameter annotations.
1594      */
1595     void readParameterAnnotations(Symbol meth) {
1596         int numParameters;
1597         try {
1598             numParameters = buf.getByte(bp++) & 0xFF;
1599         } catch (UnderflowException e) {
1600             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
1601         }
1602         if (parameterAnnotations == null) {
1603             parameterAnnotations = new ParameterAnnotations[numParameters];
1604         } else if (parameterAnnotations.length != numParameters) {
1605             //the RuntimeVisibleParameterAnnotations and RuntimeInvisibleParameterAnnotations
1606             //provide annotations for a different number of parameters, ignore:
1607             if (lintClassfile) {
1608                 log.warning(LintCategory.CLASSFILE, Warnings.RuntimeVisibleInvisibleParamAnnotationsMismatch(currentClassFile));
1609             }
1610             for (int pnum = 0; pnum < numParameters; pnum++) {
1611                 readAnnotations();
1612             }
1613             parameterAnnotations = null;
1614             return ;
1615         }
1616         for (int pnum = 0; pnum < numParameters; pnum++) {
1617             if (parameterAnnotations[pnum] == null) {
1618                 parameterAnnotations[pnum] = new ParameterAnnotations();
1619             }
1620             parameterAnnotations[pnum].add(readAnnotations());
1621         }
1622     }
1623 
1624     void attachTypeAnnotations(final Symbol sym) {
1625         int numAttributes = nextChar();
1626         if (numAttributes != 0) {
1627             ListBuffer<TypeAnnotationProxy> proxies = new ListBuffer<>();
1628             for (int i = 0; i < numAttributes; i++)
1629                 proxies.append(readTypeAnnotation());
1630             annotate.normal(new TypeAnnotationCompleter(sym, proxies.toList()));
1631         }
1632     }
1633 
1634     /** Attach the default value for an annotation element.
1635      */
1636     void attachAnnotationDefault(final Symbol sym) {
1637         final MethodSymbol meth = (MethodSymbol)sym; // only on methods
1638         final Attribute value = readAttributeValue();
1639 
1640         // The default value is set later during annotation. It might
1641         // be the case that the Symbol sym is annotated _after_ the
1642         // repeating instances that depend on this default value,
1643         // because of this we set an interim value that tells us this
1644         // element (most likely) has a default.
1645         //
1646         // Set interim value for now, reset just before we do this
1647         // properly at annotate time.
1648         meth.defaultValue = value;
1649         annotate.normal(new AnnotationDefaultCompleter(meth, value));
1650     }
1651 
1652     Type readTypeOrClassSymbol(int i) {
1653         return readTypeToProxy(i);
1654     }
1655     Type readTypeToProxy(int i) {
1656         if (currentModule.module_info == currentOwner) {
1657             return new ProxyType(i);
1658         } else {
1659             return poolReader.getType(i);
1660         }
1661     }
1662 
1663     CompoundAnnotationProxy readCompoundAnnotation() {
1664         Type t;
1665         if (currentModule.module_info == currentOwner) {
1666             int cpIndex = nextChar();
1667             t = new ProxyType(cpIndex);
1668         } else {
1669             t = readTypeOrClassSymbol(nextChar());
1670         }
1671         int numFields = nextChar();
1672         ListBuffer<Pair<Name,Attribute>> pairs = new ListBuffer<>();
1673         for (int i=0; i<numFields; i++) {
1674             Name name = poolReader.getName(nextChar());
1675             Attribute value = readAttributeValue();
1676             pairs.append(new Pair<>(name, value));
1677         }
1678         return new CompoundAnnotationProxy(t, pairs.toList());
1679     }
1680 
1681     TypeAnnotationProxy readTypeAnnotation() {
1682         TypeAnnotationPosition position = readPosition();
1683         CompoundAnnotationProxy proxy = readCompoundAnnotation();
1684 
1685         return new TypeAnnotationProxy(proxy, position);
1686     }
1687 
1688     TypeAnnotationPosition readPosition() {
1689         int tag = nextByte(); // TargetType tag is a byte
1690 
1691         if (!TargetType.isValidTargetTypeValue(tag))
1692             throw badClassFile("bad.type.annotation.value", String.format("0x%02X", tag));
1693 
1694         TargetType type = TargetType.fromTargetTypeValue(tag);
1695 
1696         switch (type) {
1697         // instanceof
1698         case INSTANCEOF: {
1699             final int offset = nextChar();
1700             final TypeAnnotationPosition position =
1701                 TypeAnnotationPosition.instanceOf(readTypePath());
1702             position.offset = offset;
1703             return position;
1704         }
1705         // new expression
1706         case NEW: {
1707             final int offset = nextChar();
1708             final TypeAnnotationPosition position =
1709                 TypeAnnotationPosition.newObj(readTypePath());
1710             position.offset = offset;
1711             return position;
1712         }
1713         // constructor/method reference receiver
1714         case CONSTRUCTOR_REFERENCE: {
1715             final int offset = nextChar();
1716             final TypeAnnotationPosition position =
1717                 TypeAnnotationPosition.constructorRef(readTypePath());
1718             position.offset = offset;
1719             return position;
1720         }
1721         case METHOD_REFERENCE: {
1722             final int offset = nextChar();
1723             final TypeAnnotationPosition position =
1724                 TypeAnnotationPosition.methodRef(readTypePath());
1725             position.offset = offset;
1726             return position;
1727         }
1728         // local variable
1729         case LOCAL_VARIABLE: {
1730             final int table_length = nextChar();
1731             final int[] newLvarOffset = new int[table_length];
1732             final int[] newLvarLength = new int[table_length];
1733             final int[] newLvarIndex = new int[table_length];
1734 
1735             for (int i = 0; i < table_length; ++i) {
1736                 newLvarOffset[i] = nextChar();
1737                 newLvarLength[i] = nextChar();
1738                 newLvarIndex[i] = nextChar();
1739             }
1740 
1741             final TypeAnnotationPosition position =
1742                     TypeAnnotationPosition.localVariable(readTypePath());
1743             position.lvarOffset = newLvarOffset;
1744             position.lvarLength = newLvarLength;
1745             position.lvarIndex = newLvarIndex;
1746             return position;
1747         }
1748         // resource variable
1749         case RESOURCE_VARIABLE: {
1750             final int table_length = nextChar();
1751             final int[] newLvarOffset = new int[table_length];
1752             final int[] newLvarLength = new int[table_length];
1753             final int[] newLvarIndex = new int[table_length];
1754 
1755             for (int i = 0; i < table_length; ++i) {
1756                 newLvarOffset[i] = nextChar();
1757                 newLvarLength[i] = nextChar();
1758                 newLvarIndex[i] = nextChar();
1759             }
1760 
1761             final TypeAnnotationPosition position =
1762                     TypeAnnotationPosition.resourceVariable(readTypePath());
1763             position.lvarOffset = newLvarOffset;
1764             position.lvarLength = newLvarLength;
1765             position.lvarIndex = newLvarIndex;
1766             return position;
1767         }
1768         // exception parameter
1769         case EXCEPTION_PARAMETER: {
1770             final int exception_index = nextChar();
1771             final TypeAnnotationPosition position =
1772                 TypeAnnotationPosition.exceptionParameter(readTypePath());
1773             position.setExceptionIndex(exception_index);
1774             return position;
1775         }
1776         // method receiver
1777         case METHOD_RECEIVER:
1778             return TypeAnnotationPosition.methodReceiver(readTypePath());
1779         // type parameter
1780         case CLASS_TYPE_PARAMETER: {
1781             final int parameter_index = nextByte();
1782             return TypeAnnotationPosition
1783                 .typeParameter(readTypePath(), parameter_index);
1784         }
1785         case METHOD_TYPE_PARAMETER: {
1786             final int parameter_index = nextByte();
1787             return TypeAnnotationPosition
1788                 .methodTypeParameter(readTypePath(), parameter_index);
1789         }
1790         // type parameter bound
1791         case CLASS_TYPE_PARAMETER_BOUND: {
1792             final int parameter_index = nextByte();
1793             final int bound_index = nextByte();
1794             return TypeAnnotationPosition
1795                 .typeParameterBound(readTypePath(), parameter_index,
1796                                     bound_index);
1797         }
1798         case METHOD_TYPE_PARAMETER_BOUND: {
1799             final int parameter_index = nextByte();
1800             final int bound_index = nextByte();
1801             return TypeAnnotationPosition
1802                 .methodTypeParameterBound(readTypePath(), parameter_index,
1803                                           bound_index);
1804         }
1805         // class extends or implements clause
1806         case CLASS_EXTENDS: {
1807             final int type_index = nextChar();
1808             return TypeAnnotationPosition.classExtends(readTypePath(),
1809                                                        type_index);
1810         }
1811         // throws
1812         case THROWS: {
1813             final int type_index = nextChar();
1814             return TypeAnnotationPosition.methodThrows(readTypePath(),
1815                                                        type_index);
1816         }
1817         // method parameter
1818         case METHOD_FORMAL_PARAMETER: {
1819             final int parameter_index = nextByte();
1820             return TypeAnnotationPosition.methodParameter(readTypePath(),
1821                                                           parameter_index);
1822         }
1823         // type cast
1824         case CAST: {
1825             final int offset = nextChar();
1826             final int type_index = nextByte();
1827             final TypeAnnotationPosition position =
1828                 TypeAnnotationPosition.typeCast(readTypePath(), type_index);
1829             position.offset = offset;
1830             return position;
1831         }
1832         // method/constructor/reference type argument
1833         case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT: {
1834             final int offset = nextChar();
1835             final int type_index = nextByte();
1836             final TypeAnnotationPosition position = TypeAnnotationPosition
1837                 .constructorInvocationTypeArg(readTypePath(), type_index);
1838             position.offset = offset;
1839             return position;
1840         }
1841         case METHOD_INVOCATION_TYPE_ARGUMENT: {
1842             final int offset = nextChar();
1843             final int type_index = nextByte();
1844             final TypeAnnotationPosition position = TypeAnnotationPosition
1845                 .methodInvocationTypeArg(readTypePath(), type_index);
1846             position.offset = offset;
1847             return position;
1848         }
1849         case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT: {
1850             final int offset = nextChar();
1851             final int type_index = nextByte();
1852             final TypeAnnotationPosition position = TypeAnnotationPosition
1853                 .constructorRefTypeArg(readTypePath(), type_index);
1854             position.offset = offset;
1855             return position;
1856         }
1857         case METHOD_REFERENCE_TYPE_ARGUMENT: {
1858             final int offset = nextChar();
1859             final int type_index = nextByte();
1860             final TypeAnnotationPosition position = TypeAnnotationPosition
1861                 .methodRefTypeArg(readTypePath(), type_index);
1862             position.offset = offset;
1863             return position;
1864         }
1865         // We don't need to worry about these
1866         case METHOD_RETURN:
1867             return TypeAnnotationPosition.methodReturn(readTypePath());
1868         case FIELD:
1869             return TypeAnnotationPosition.field(readTypePath());
1870         case UNKNOWN:
1871             throw new AssertionError("jvm.ClassReader: UNKNOWN target type should never occur!");
1872         default:
1873             throw new AssertionError("jvm.ClassReader: Unknown target type for position: " + type);
1874         }
1875     }
1876 
1877     List<TypeAnnotationPosition.TypePathEntry> readTypePath() {
1878         int len = nextByte();
1879         ListBuffer<Integer> loc = new ListBuffer<>();
1880         for (int i = 0; i < len * TypeAnnotationPosition.TypePathEntry.bytesPerEntry; ++i)
1881             loc = loc.append(nextByte());
1882 
1883         return TypeAnnotationPosition.getTypePathFromBinary(loc.toList());
1884 
1885     }
1886 
1887     /**
1888      * Helper function to read an optional pool entry (with given function); this is used while parsing
1889      * InnerClasses and EnclosingMethod attributes, as well as when parsing supertype descriptor,
1890      * as per JVMS.
1891      */
1892     <Z> Z optPoolEntry(int index, IntFunction<Z> poolFunc, Z defaultValue) {
1893         return (index == 0) ?
1894                 defaultValue :
1895                 poolFunc.apply(index);
1896     }
1897 
1898     Attribute readAttributeValue() {
1899         char c;
1900         try {
1901             c = (char)buf.getByte(bp++);
1902         } catch (UnderflowException e) {
1903             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
1904         }
1905         switch (c) {
1906         case 'B':
1907             return new Attribute.Constant(syms.byteType, poolReader.getConstant(nextChar()));
1908         case 'C':
1909             return new Attribute.Constant(syms.charType, poolReader.getConstant(nextChar()));
1910         case 'D':
1911             return new Attribute.Constant(syms.doubleType, poolReader.getConstant(nextChar()));
1912         case 'F':
1913             return new Attribute.Constant(syms.floatType, poolReader.getConstant(nextChar()));
1914         case 'I':
1915             return new Attribute.Constant(syms.intType, poolReader.getConstant(nextChar()));
1916         case 'J':
1917             return new Attribute.Constant(syms.longType, poolReader.getConstant(nextChar()));
1918         case 'S':
1919             return new Attribute.Constant(syms.shortType, poolReader.getConstant(nextChar()));
1920         case 'Z':
1921             return new Attribute.Constant(syms.booleanType, poolReader.getConstant(nextChar()));
1922         case 's':
1923             return new Attribute.Constant(syms.stringType, poolReader.getName(nextChar()).toString());
1924         case 'e':
1925             return new EnumAttributeProxy(readTypeToProxy(nextChar()), poolReader.getName(nextChar()));
1926         case 'c':
1927             return new ClassAttributeProxy(readTypeOrClassSymbol(nextChar()));
1928         case '[': {
1929             int n = nextChar();
1930             ListBuffer<Attribute> l = new ListBuffer<>();
1931             for (int i=0; i<n; i++)
1932                 l.append(readAttributeValue());
1933             return new ArrayAttributeProxy(l.toList());
1934         }
1935         case '@':
1936             return readCompoundAnnotation();
1937         default:
1938             throw new AssertionError("unknown annotation tag '" + c + "'");
1939         }
1940     }
1941 
1942     interface ProxyVisitor extends Attribute.Visitor {
1943         void visitEnumAttributeProxy(EnumAttributeProxy proxy);
1944         void visitClassAttributeProxy(ClassAttributeProxy proxy);
1945         void visitArrayAttributeProxy(ArrayAttributeProxy proxy);
1946         void visitCompoundAnnotationProxy(CompoundAnnotationProxy proxy);
1947     }
1948 
1949     static class EnumAttributeProxy extends Attribute {
1950         Type enumType;
1951         Name enumerator;
1952         public EnumAttributeProxy(Type enumType, Name enumerator) {
1953             super(null);
1954             this.enumType = enumType;
1955             this.enumerator = enumerator;
1956         }
1957         public void accept(Visitor v) { ((ProxyVisitor)v).visitEnumAttributeProxy(this); }
1958         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1959         public String toString() {
1960             return "/*proxy enum*/" + enumType + "." + enumerator;
1961         }
1962     }
1963 
1964     static class ClassAttributeProxy extends Attribute {
1965         Type classType;
1966         public ClassAttributeProxy(Type classType) {
1967             super(null);
1968             this.classType = classType;
1969         }
1970         public void accept(Visitor v) { ((ProxyVisitor)v).visitClassAttributeProxy(this); }
1971         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1972         public String toString() {
1973             return "/*proxy class*/" + classType + ".class";
1974         }
1975     }
1976 
1977     static class ArrayAttributeProxy extends Attribute {
1978         List<Attribute> values;
1979         ArrayAttributeProxy(List<Attribute> values) {
1980             super(null);
1981             this.values = values;
1982         }
1983         public void accept(Visitor v) { ((ProxyVisitor)v).visitArrayAttributeProxy(this); }
1984         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1985         public String toString() {
1986             return "{" + values + "}";
1987         }
1988     }
1989 
1990     /** A temporary proxy representing a compound attribute.
1991      */
1992     static class CompoundAnnotationProxy extends Attribute {
1993         final List<Pair<Name,Attribute>> values;
1994         public CompoundAnnotationProxy(Type type,
1995                                       List<Pair<Name,Attribute>> values) {
1996             super(type);
1997             this.values = values;
1998         }
1999         public void accept(Visitor v) { ((ProxyVisitor)v).visitCompoundAnnotationProxy(this); }
2000         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2001         public String toString() {
2002             StringBuilder buf = new StringBuilder();
2003             buf.append("@");
2004             buf.append(type.tsym.getQualifiedName());
2005             buf.append("/*proxy*/{");
2006             boolean first = true;
2007             for (List<Pair<Name,Attribute>> v = values;
2008                  v.nonEmpty(); v = v.tail) {
2009                 Pair<Name,Attribute> value = v.head;
2010                 if (!first) buf.append(",");
2011                 first = false;
2012                 buf.append(value.fst);
2013                 buf.append("=");
2014                 buf.append(value.snd);
2015             }
2016             buf.append("}");
2017             return buf.toString();
2018         }
2019     }
2020 
2021     /** A temporary proxy representing a type annotation.
2022      */
2023     static class TypeAnnotationProxy {
2024         final CompoundAnnotationProxy compound;
2025         final TypeAnnotationPosition position;
2026         public TypeAnnotationProxy(CompoundAnnotationProxy compound,
2027                 TypeAnnotationPosition position) {
2028             this.compound = compound;
2029             this.position = position;
2030         }
2031     }
2032 
2033     class AnnotationDeproxy implements ProxyVisitor {
2034         private ClassSymbol requestingOwner;
2035 
2036         AnnotationDeproxy(ClassSymbol owner) {
2037             this.requestingOwner = owner;
2038         }
2039 
2040         List<Attribute.Compound> deproxyCompoundList(List<CompoundAnnotationProxy> pl) {
2041             // also must fill in types!!!!
2042             ListBuffer<Attribute.Compound> buf = new ListBuffer<>();
2043             for (List<CompoundAnnotationProxy> l = pl; l.nonEmpty(); l=l.tail) {
2044                 buf.append(deproxyCompound(l.head));
2045             }
2046             return buf.toList();
2047         }
2048 
2049         Attribute.Compound deproxyCompound(CompoundAnnotationProxy a) {
2050             Type annotationType = resolvePossibleProxyType(a.type);
2051             ListBuffer<Pair<Symbol.MethodSymbol,Attribute>> buf = new ListBuffer<>();
2052             for (List<Pair<Name,Attribute>> l = a.values;
2053                  l.nonEmpty();
2054                  l = l.tail) {
2055                 MethodSymbol meth = findAccessMethod(annotationType, l.head.fst);
2056                 buf.append(new Pair<>(meth, deproxy(meth.type.getReturnType(), l.head.snd)));
2057             }
2058             return new Attribute.Compound(annotationType, buf.toList());
2059         }
2060 
2061         MethodSymbol findAccessMethod(Type container, Name name) {
2062             CompletionFailure failure = null;
2063             try {
2064                 for (Symbol sym : container.tsym.members().getSymbolsByName(name)) {
2065                     if (sym.kind == MTH && sym.type.getParameterTypes().length() == 0)
2066                         return (MethodSymbol) sym;
2067                 }
2068             } catch (CompletionFailure ex) {
2069                 failure = ex;
2070             }
2071             // The method wasn't found: emit a warning and recover
2072             JavaFileObject prevSource = log.useSource(requestingOwner.classfile);
2073             try {
2074                 if (lintClassfile) {
2075                     if (failure == null) {
2076                         log.warning(Warnings.AnnotationMethodNotFound(container, name));
2077                     } else {
2078                         log.warning(Warnings.AnnotationMethodNotFoundReason(container,
2079                                                                             name,
2080                                                                             failure.getDetailValue()));//diagnostic, if present
2081                     }
2082                 }
2083             } finally {
2084                 log.useSource(prevSource);
2085             }
2086             // Construct a new method type and symbol.  Use bottom
2087             // type (typeof null) as return type because this type is
2088             // a subtype of all reference types and can be converted
2089             // to primitive types by unboxing.
2090             MethodType mt = new MethodType(List.nil(),
2091                                            syms.botType,
2092                                            List.nil(),
2093                                            syms.methodClass);
2094             return new MethodSymbol(PUBLIC | ABSTRACT, name, mt, container.tsym);
2095         }
2096 
2097         Attribute result;
2098         Type type;
2099         Attribute deproxy(Type t, Attribute a) {
2100             Type oldType = type;
2101             try {
2102                 type = t;
2103                 a.accept(this);
2104                 return result;
2105             } finally {
2106                 type = oldType;
2107             }
2108         }
2109 
2110         // implement Attribute.Visitor below
2111 
2112         public void visitConstant(Attribute.Constant value) {
2113             // assert value.type == type;
2114             result = value;
2115         }
2116 
2117         public void visitClass(Attribute.Class clazz) {
2118             result = clazz;
2119         }
2120 
2121         public void visitEnum(Attribute.Enum e) {
2122             throw new AssertionError(); // shouldn't happen
2123         }
2124 
2125         public void visitCompound(Attribute.Compound compound) {
2126             throw new AssertionError(); // shouldn't happen
2127         }
2128 
2129         public void visitArray(Attribute.Array array) {
2130             throw new AssertionError(); // shouldn't happen
2131         }
2132 
2133         public void visitError(Attribute.Error e) {
2134             throw new AssertionError(); // shouldn't happen
2135         }
2136 
2137         public void visitEnumAttributeProxy(EnumAttributeProxy proxy) {
2138             // type.tsym.flatName() should == proxy.enumFlatName
2139             Type enumType = resolvePossibleProxyType(proxy.enumType);
2140             TypeSymbol enumTypeSym = enumType.tsym;
2141             VarSymbol enumerator = null;
2142             CompletionFailure failure = null;
2143             try {
2144                 for (Symbol sym : enumTypeSym.members().getSymbolsByName(proxy.enumerator)) {
2145                     if (sym.kind == VAR) {
2146                         enumerator = (VarSymbol)sym;
2147                         break;
2148                     }
2149                 }
2150             }
2151             catch (CompletionFailure ex) {
2152                 failure = ex;
2153             }
2154             if (enumerator == null) {
2155                 if (failure != null) {
2156                     log.warning(Warnings.UnknownEnumConstantReason(currentClassFile,
2157                                                                    enumTypeSym,
2158                                                                    proxy.enumerator,
2159                                                                    failure.getDiagnostic()));
2160                 } else {
2161                     log.warning(Warnings.UnknownEnumConstant(currentClassFile,
2162                                                              enumTypeSym,
2163                                                              proxy.enumerator));
2164                 }
2165                 result = new Attribute.Enum(enumTypeSym.type,
2166                         new VarSymbol(0, proxy.enumerator, syms.botType, enumTypeSym));
2167             } else {
2168                 result = new Attribute.Enum(enumTypeSym.type, enumerator);
2169             }
2170         }
2171 
2172         @Override
2173         public void visitClassAttributeProxy(ClassAttributeProxy proxy) {
2174             Type classType = resolvePossibleProxyType(proxy.classType);
2175             result = new Attribute.Class(types, classType);
2176         }
2177 
2178         public void visitArrayAttributeProxy(ArrayAttributeProxy proxy) {
2179             int length = proxy.values.length();
2180             Attribute[] ats = new Attribute[length];
2181             Type elemtype = types.elemtype(type);
2182             int i = 0;
2183             for (List<Attribute> p = proxy.values; p.nonEmpty(); p = p.tail) {
2184                 ats[i++] = deproxy(elemtype, p.head);
2185             }
2186             result = new Attribute.Array(type, ats);
2187         }
2188 
2189         public void visitCompoundAnnotationProxy(CompoundAnnotationProxy proxy) {
2190             result = deproxyCompound(proxy);
2191         }
2192 
2193         Type resolvePossibleProxyType(Type t) {
2194             if (t instanceof ProxyType proxyType) {
2195                 Assert.check(requestingOwner.owner instanceof ModuleSymbol);
2196                 ModuleSymbol prevCurrentModule = currentModule;
2197                 currentModule = (ModuleSymbol) requestingOwner.owner;
2198                 try {
2199                     return proxyType.resolve();
2200                 } finally {
2201                     currentModule = prevCurrentModule;
2202                 }
2203             } else {
2204                 return t;
2205             }
2206         }
2207     }
2208 
2209     class AnnotationDefaultCompleter extends AnnotationDeproxy implements Runnable {
2210         final MethodSymbol sym;
2211         final Attribute value;
2212         final JavaFileObject classFile = currentClassFile;
2213 
2214         AnnotationDefaultCompleter(MethodSymbol sym, Attribute value) {
2215             super(currentOwner.kind == MTH
2216                     ? currentOwner.enclClass() : (ClassSymbol)currentOwner);
2217             this.sym = sym;
2218             this.value = value;
2219         }
2220 
2221         @Override
2222         public void run() {
2223             JavaFileObject previousClassFile = currentClassFile;
2224             try {
2225                 // Reset the interim value set earlier in
2226                 // attachAnnotationDefault().
2227                 sym.defaultValue = null;
2228                 currentClassFile = classFile;
2229                 sym.defaultValue = deproxy(sym.type.getReturnType(), value);
2230             } finally {
2231                 currentClassFile = previousClassFile;
2232             }
2233         }
2234 
2235         @Override
2236         public String toString() {
2237             return " ClassReader store default for " + sym.owner + "." + sym + " is " + value;
2238         }
2239     }
2240 
2241     class AnnotationCompleter extends AnnotationDeproxy implements Runnable {
2242         final Symbol sym;
2243         final List<CompoundAnnotationProxy> l;
2244         final JavaFileObject classFile;
2245 
2246         AnnotationCompleter(Symbol sym, List<CompoundAnnotationProxy> l) {
2247             super(currentOwner.kind == MTH
2248                     ? currentOwner.enclClass() : (ClassSymbol)currentOwner);
2249             if (sym.kind == TYP && sym.owner.kind == MDL) {
2250                 this.sym = sym.owner;
2251             } else {
2252                 this.sym = sym;
2253             }
2254             this.l = l;
2255             this.classFile = currentClassFile;
2256         }
2257 
2258         @Override
2259         public void run() {
2260             JavaFileObject previousClassFile = currentClassFile;
2261             try {
2262                 currentClassFile = classFile;
2263                 List<Attribute.Compound> newList = deproxyCompoundList(l);
2264                 for (Attribute.Compound attr : newList) {
2265                     if (attr.type.tsym == syms.deprecatedType.tsym) {
2266                         sym.flags_field |= (DEPRECATED | DEPRECATED_ANNOTATION);
2267                         Attribute forRemoval = attr.member(names.forRemoval);
2268                         if (forRemoval instanceof Attribute.Constant constant) {
2269                             if (constant.type == syms.booleanType && ((Integer) constant.value) != 0) {
2270                                 sym.flags_field |= DEPRECATED_REMOVAL;
2271                             }
2272                         }
2273                     }
2274                 }
2275                 if (sym.annotationsPendingCompletion()) {
2276                     sym.setDeclarationAttributes(newList);
2277                 } else {
2278                     sym.appendAttributes(newList);
2279                 }
2280             } finally {
2281                 currentClassFile = previousClassFile;
2282             }
2283         }
2284 
2285         @Override
2286         public String toString() {
2287             return " ClassReader annotate " + sym.owner + "." + sym + " with " + l;
2288         }
2289     }
2290 
2291     class TypeAnnotationCompleter extends AnnotationCompleter {
2292 
2293         List<TypeAnnotationProxy> proxies;
2294 
2295         TypeAnnotationCompleter(Symbol sym,
2296                 List<TypeAnnotationProxy> proxies) {
2297             super(sym, List.nil());
2298             this.proxies = proxies;
2299         }
2300 
2301         List<Attribute.TypeCompound> deproxyTypeCompoundList(List<TypeAnnotationProxy> proxies) {
2302             ListBuffer<Attribute.TypeCompound> buf = new ListBuffer<>();
2303             for (TypeAnnotationProxy proxy: proxies) {
2304                 Attribute.Compound compound = deproxyCompound(proxy.compound);
2305                 Attribute.TypeCompound typeCompound = new Attribute.TypeCompound(compound, proxy.position);
2306                 buf.add(typeCompound);
2307             }
2308             return buf.toList();
2309         }
2310 
2311         @Override
2312         public void run() {
2313             JavaFileObject previousClassFile = currentClassFile;
2314             try {
2315                 currentClassFile = classFile;
2316                 List<Attribute.TypeCompound> newList = deproxyTypeCompoundList(proxies);
2317                 sym.setTypeAttributes(newList.prependList(sym.getRawTypeAttributes()));
2318                 addTypeAnnotationsToSymbol(sym, newList);
2319             } finally {
2320                 currentClassFile = previousClassFile;
2321             }
2322         }
2323     }
2324 
2325     /**
2326      * Rewrites types in the given symbol to include type annotations.
2327      *
2328      * <p>The list of type annotations includes annotations for all types in the signature of the
2329      * symbol. Associating the annotations with the correct type requires interpreting the JVMS
2330      * 4.7.20-A target_type to locate the correct type to rewrite, and then interpreting the JVMS
2331      * 4.7.20.2 type_path to associate the annotation with the correct contained type.
2332      */
2333     private void addTypeAnnotationsToSymbol(Symbol s, List<Attribute.TypeCompound> attributes) {
2334         try {
2335             new TypeAnnotationSymbolVisitor(attributes).visit(s, null);
2336         } catch (CompletionFailure ex) {
2337             JavaFileObject prev = log.useSource(currentClassFile);
2338             try {
2339                 log.error(Errors.CantAttachTypeAnnotations(attributes, s.owner, s.name, ex.getDetailValue()));
2340             } finally {
2341                 log.useSource(prev);
2342             }
2343         }
2344     }
2345 
2346     private static class TypeAnnotationSymbolVisitor
2347             extends Types.DefaultSymbolVisitor<Void, Void> {
2348 
2349         private final List<Attribute.TypeCompound> attributes;
2350 
2351         private TypeAnnotationSymbolVisitor(List<Attribute.TypeCompound> attributes) {
2352             this.attributes = attributes;
2353         }
2354 
2355         /**
2356          * A supertype_index value of 65535 specifies that the annotation appears on the superclass
2357          * in an extends clause of a class declaration, see JVMS 4.7.20.1
2358          */
2359         public static final int SUPERCLASS_INDEX = 65535;
2360 
2361         @Override
2362         public Void visitClassSymbol(Symbol.ClassSymbol s, Void unused) {
2363             ClassType t = (ClassType) s.type;
2364             int i = 0;
2365             ListBuffer<Type> interfaces = new ListBuffer<>();
2366             for (Type itf : t.interfaces_field) {
2367                 interfaces.add(addTypeAnnotations(itf, classExtends(i++)));
2368             }
2369             t.interfaces_field = interfaces.toList();
2370             t.supertype_field = addTypeAnnotations(t.supertype_field, classExtends(SUPERCLASS_INDEX));
2371             if (t.typarams_field != null) {
2372                 t.typarams_field =
2373                         rewriteTypeParameters(
2374                                 t.typarams_field, TargetType.CLASS_TYPE_PARAMETER_BOUND);
2375             }
2376             return null;
2377         }
2378 
2379         @Override
2380         public Void visitMethodSymbol(Symbol.MethodSymbol s, Void unused) {
2381             Type t = s.type;
2382             if (t.hasTag(TypeTag.FORALL)) {
2383                 Type.ForAll fa = (Type.ForAll) t;
2384                 fa.tvars = rewriteTypeParameters(fa.tvars, TargetType.METHOD_TYPE_PARAMETER_BOUND);
2385                 t = fa.qtype;
2386             }
2387             MethodType mt = (MethodType) t;
2388             ListBuffer<Type> argtypes = new ListBuffer<>();
2389             int i = 0;
2390             for (Symbol.VarSymbol param : s.params) {
2391                 param.type = addTypeAnnotations(param.type, methodFormalParameter(i++));
2392                 argtypes.add(param.type);
2393             }
2394             mt.argtypes = argtypes.toList();
2395             ListBuffer<Type> thrown = new ListBuffer<>();
2396             i = 0;
2397             for (Type thrownType : mt.thrown) {
2398                 thrown.add(addTypeAnnotations(thrownType, thrownType(i++)));
2399             }
2400             mt.thrown = thrown.toList();
2401             /* possible information loss if the type of the method is void then we can't add type
2402              * annotations to it
2403              */
2404             if (!mt.restype.hasTag(TypeTag.VOID)) {
2405                 mt.restype = addTypeAnnotations(mt.restype, TargetType.METHOD_RETURN);
2406             }
2407 
2408             Type recvtype = mt.recvtype != null ? mt.recvtype : s.implicitReceiverType();
2409             if (recvtype != null) {
2410                 Type annotated = addTypeAnnotations(recvtype, TargetType.METHOD_RECEIVER);
2411                 if (annotated != recvtype) {
2412                     mt.recvtype = annotated;
2413                 }
2414             }
2415             return null;
2416         }
2417 
2418         @Override
2419         public Void visitVarSymbol(Symbol.VarSymbol s, Void unused) {
2420             s.type = addTypeAnnotations(s.type, TargetType.FIELD);
2421             return null;
2422         }
2423 
2424         @Override
2425         public Void visitSymbol(Symbol s, Void unused) {
2426             return null;
2427         }
2428 
2429         private List<Type> rewriteTypeParameters(List<Type> tvars, TargetType boundType) {
2430             ListBuffer<Type> tvarbuf = new ListBuffer<>();
2431             int typeVariableIndex = 0;
2432             for (Type tvar : tvars) {
2433                 Type bound = tvar.getUpperBound();
2434                 if (bound.isCompound()) {
2435                     ClassType ct = (ClassType) bound;
2436                     int boundIndex = 0;
2437                     if (ct.supertype_field != null) {
2438                         ct.supertype_field =
2439                                 addTypeAnnotations(
2440                                         ct.supertype_field,
2441                                         typeParameterBound(
2442                                                 boundType, typeVariableIndex, boundIndex++));
2443                     }
2444                     ListBuffer<Type> itfbuf = new ListBuffer<>();
2445                     for (Type itf : ct.interfaces_field) {
2446                         itfbuf.add(
2447                                 addTypeAnnotations(
2448                                         itf,
2449                                         typeParameterBound(
2450                                                 boundType, typeVariableIndex, boundIndex++)));
2451                     }
2452                     ct.interfaces_field = itfbuf.toList();
2453                 } else {
2454                     bound =
2455                             addTypeAnnotations(
2456                                     bound,
2457                                     typeParameterBound(
2458                                             boundType,
2459                                             typeVariableIndex,
2460                                             bound.isInterface() ? 1 : 0));
2461                 }
2462                 ((TypeVar) tvar).setUpperBound(bound);
2463                 tvarbuf.add(tvar);
2464                 typeVariableIndex++;
2465             }
2466             return tvarbuf.toList();
2467         }
2468 
2469         private Type addTypeAnnotations(Type type, TargetType targetType) {
2470             return addTypeAnnotations(type, pos -> pos.type == targetType);
2471         }
2472 
2473         private Type addTypeAnnotations(Type type, Predicate<TypeAnnotationPosition> filter) {
2474             Assert.checkNonNull(type);
2475 
2476             // Find type annotations that match the given target type
2477             ListBuffer<Attribute.TypeCompound> filtered = new ListBuffer<>();
2478             for (Attribute.TypeCompound attribute : this.attributes) {
2479                 if (filter.test(attribute.position)) {
2480                     filtered.add(attribute);
2481                 }
2482             }
2483             if (filtered.isEmpty()) {
2484                 return type;
2485             }
2486 
2487             // Group the matching annotations by their type path. Each group of annotations will be
2488             // added to a type at that location.
2489             Map<List<TypeAnnotationPosition.TypePathEntry>, ListBuffer<Attribute.TypeCompound>>
2490                     attributesByPath = new HashMap<>();
2491             for (Attribute.TypeCompound attribute : filtered.toList()) {
2492                 attributesByPath
2493                         .computeIfAbsent(attribute.position.location, k -> new ListBuffer<>())
2494                         .add(attribute);
2495             }
2496 
2497             // Rewrite the type and add the annotations
2498             type = new TypeAnnotationStructuralTypeMapping(attributesByPath).visit(type, List.nil());
2499 
2500             return type;
2501         }
2502 
2503         private static Predicate<TypeAnnotationPosition> typeParameterBound(
2504                 TargetType targetType, int parameterIndex, int boundIndex) {
2505             return pos ->
2506                     pos.type == targetType
2507                             && pos.parameter_index == parameterIndex
2508                             && pos.bound_index == boundIndex;
2509         }
2510 
2511         private static Predicate<TypeAnnotationPosition> methodFormalParameter(int index) {
2512             return pos ->
2513                     pos.type == TargetType.METHOD_FORMAL_PARAMETER && pos.parameter_index == index;
2514         }
2515 
2516         private static Predicate<TypeAnnotationPosition> thrownType(int index) {
2517             return pos -> pos.type == TargetType.THROWS && pos.type_index == index;
2518         }
2519 
2520         private static Predicate<TypeAnnotationPosition> classExtends(int index) {
2521             return pos -> pos.type == TargetType.CLASS_EXTENDS && pos.type_index == index;
2522         }
2523     }
2524 
2525     /**
2526      * A type mapping that rewrites the type to include type annotations.
2527      *
2528      * <p>This logic is similar to {@link Type.StructuralTypeMapping}, but also tracks the path to
2529      * the contained types being rewritten, and so cannot easily share the existing logic.
2530      */
2531     private static final class TypeAnnotationStructuralTypeMapping
2532             extends Types.TypeMapping<List<TypeAnnotationPosition.TypePathEntry>> {
2533 
2534         private final Map<List<TypeAnnotationPosition.TypePathEntry>,
2535                 ListBuffer<Attribute.TypeCompound>> attributesByPath;
2536 
2537         private TypeAnnotationStructuralTypeMapping(
2538                 Map<List<TypeAnnotationPosition.TypePathEntry>, ListBuffer<Attribute.TypeCompound>>
2539                     attributesByPath) {
2540             this.attributesByPath = attributesByPath;
2541         }
2542 
2543 
2544         @Override
2545         public Type visitClassType(ClassType t, List<TypeAnnotationPosition.TypePathEntry> path) {
2546             // As described in JVMS 4.7.20.2, type annotations on nested types are located with
2547             // 'left-to-right' steps starting on 'the outermost part of the type for which a type
2548             // annotation is admissible'. So the current path represents the outermost containing
2549             // type of the type being visited, and we add type path steps for every contained nested
2550             // type.
2551             Type outer = t.getEnclosingType();
2552             Type outer1 = outer != Type.noType ? visit(outer, path) : outer;
2553             for (Type curr = t.getEnclosingType();
2554                     curr != Type.noType;
2555                     curr = curr.getEnclosingType()) {
2556                 path = path.append(TypeAnnotationPosition.TypePathEntry.INNER_TYPE);
2557             }
2558             List<Type> typarams = t.getTypeArguments();
2559             List<Type> typarams1 = rewriteTypeParams(path, typarams);
2560             if (outer1 != outer || typarams != typarams1) {
2561                 t = new ClassType(outer1, typarams1, t.tsym, t.getMetadata());
2562             }
2563             return reannotate(t, path);
2564         }
2565 
2566         private List<Type> rewriteTypeParams(
2567                 List<TypeAnnotationPosition.TypePathEntry> path, List<Type> typarams) {
2568             var i = IntStream.iterate(0, x -> x + 1).iterator();
2569             return typarams.map(typaram -> visit(typaram,
2570                     path.append(new TypeAnnotationPosition.TypePathEntry(
2571                             TypeAnnotationPosition.TypePathEntryKind.TYPE_ARGUMENT, i.nextInt()))));
2572         }
2573 
2574         @Override
2575         public Type visitWildcardType(
2576                 WildcardType wt, List<TypeAnnotationPosition.TypePathEntry> path) {
2577             Type t = wt.type;
2578             if (t != null) {
2579                 t = visit(t, path.append(TypeAnnotationPosition.TypePathEntry.WILDCARD));
2580             }
2581             if (t != wt.type) {
2582                 wt = new WildcardType(t, wt.kind, wt.tsym, wt.bound, wt.getMetadata());
2583             }
2584             return reannotate(wt, path);
2585         }
2586 
2587         @Override
2588         public Type visitArrayType(ArrayType t, List<TypeAnnotationPosition.TypePathEntry> path) {
2589             Type elemtype = t.elemtype;
2590             Type elemtype1 =
2591                     visit(elemtype, path.append(TypeAnnotationPosition.TypePathEntry.ARRAY));
2592             if (elemtype1 != elemtype)  {
2593                 t = new ArrayType(elemtype1, t.tsym, t.getMetadata());
2594             }
2595             return reannotate(t, path);
2596         }
2597 
2598         @Override
2599         public Type visitType(Type t, List<TypeAnnotationPosition.TypePathEntry> path) {
2600             return reannotate(t, path);
2601         }
2602 
2603         Type reannotate(Type type, List<TypeAnnotationPosition.TypePathEntry> path) {
2604             List<Attribute.TypeCompound> attributes = attributesForPath(path);
2605             if (attributes.isEmpty()) {
2606                 return type;
2607             }
2608             // Runtime-visible and -invisible annotations are completed separately, so if the same
2609             // type has annotations from both it will get annotated twice.
2610             TypeMetadata.Annotations existing = type.getMetadata(TypeMetadata.Annotations.class);
2611             if (existing != null) {
2612                 existing.annotationBuffer().addAll(attributes);
2613                 return type;
2614             }
2615             return type.annotatedType(attributes);
2616         }
2617 
2618         List<Attribute.TypeCompound> attributesForPath(
2619                 List<TypeAnnotationPosition.TypePathEntry> path) {
2620             ListBuffer<Attribute.TypeCompound> attributes = attributesByPath.remove(path);
2621             return attributes != null ? attributes.toList() : List.nil();
2622         }
2623     }
2624 
2625 /* **********************************************************************
2626  * Reading Symbols
2627  ***********************************************************************/
2628 
2629     /** Read a field.
2630      */
2631     VarSymbol readField() {
2632         char rawFlags = nextChar();
2633         long flags = adjustFieldFlags(rawFlags);
2634         Name name = poolReader.getName(nextChar());
2635         Type type = poolReader.getType(nextChar());
2636         VarSymbol v = new VarSymbol(flags, name, type, currentOwner);
2637         readMemberAttrs(v);
2638         if (Integer.bitCount(rawFlags & (PUBLIC | PRIVATE | PROTECTED)) > 1 ||
2639             Integer.bitCount(rawFlags & (FINAL | VOLATILE)) > 1)
2640             throw badClassFile("illegal.flag.combo", Flags.toString((long)rawFlags), "field", v);
2641         return v;
2642     }
2643 
2644     /** Read a method.
2645      */
2646     MethodSymbol readMethod() {
2647         char rawFlags = nextChar();
2648         long flags = adjustMethodFlags(rawFlags);
2649         Name name = poolReader.getName(nextChar());
2650         Type descriptorType = poolReader.getType(nextChar());
2651         Type type = descriptorType;
2652         if (currentOwner.isInterface() &&
2653                 (flags & ABSTRACT) == 0 && !name.equals(names.clinit)) {
2654             if (majorVersion > Version.V52.major ||
2655                     (majorVersion == Version.V52.major && minorVersion >= Version.V52.minor)) {
2656                 if ((flags & (STATIC | PRIVATE)) == 0) {
2657                     currentOwner.flags_field |= DEFAULT;
2658                     flags |= DEFAULT | ABSTRACT;
2659                 }
2660             } else {
2661                 //protect against ill-formed classfiles
2662                 throw badClassFile((flags & STATIC) == 0 ? "invalid.default.interface" : "invalid.static.interface",
2663                                    Integer.toString(majorVersion),
2664                                    Integer.toString(minorVersion));
2665             }
2666         }
2667         validateMethodType(name, type);
2668         boolean forceLocal = false;
2669         if (name == names.init && currentOwner.hasOuterInstance()) {
2670             // Sometimes anonymous classes don't have an outer
2671             // instance, however, there is no reliable way to tell so
2672             // we never strip this$n
2673             // ditto for local classes. Local classes that have an enclosing method set
2674             // won't pass the "hasOuterInstance" check above, but those that don't have an
2675             // enclosing method (i.e. from initializers) will pass that check.
2676             boolean local = forceLocal =
2677                     !currentOwner.owner.members().includes(currentOwner, LookupKind.NON_RECURSIVE);
2678             if (!currentOwner.name.isEmpty() && !local)
2679                 type = new MethodType(adjustMethodParams(flags, type.getParameterTypes()),
2680                                       type.getReturnType(),
2681                                       type.getThrownTypes(),
2682                                       syms.methodClass);
2683         }
2684         MethodSymbol m = new MethodSymbol(flags, name, type, currentOwner);
2685         if (types.isSignaturePolymorphic(m)) {
2686             m.flags_field |= SIGNATURE_POLYMORPHIC;
2687         }
2688         if (saveParameterNames)
2689             initParameterNames(m);
2690         Symbol prevOwner = currentOwner;
2691         currentOwner = m;
2692         try {
2693             readMemberAttrs(m);
2694         } finally {
2695             currentOwner = prevOwner;
2696         }
2697         validateMethodType(name, m.type);
2698         adjustParameterAnnotations(m, descriptorType, forceLocal);
2699         setParameters(m, type);
2700 
2701         if (Integer.bitCount(rawFlags & (PUBLIC | PRIVATE | PROTECTED)) > 1)
2702             throw badClassFile("illegal.flag.combo", Flags.toString((long)rawFlags), "method", m);
2703         if ((flags & VARARGS) != 0) {
2704             final Type last = type.getParameterTypes().last();
2705             if (last == null || !last.hasTag(ARRAY)) {
2706                 m.flags_field &= ~VARARGS;
2707                 throw badClassFile("malformed.vararg.method", m);
2708             }
2709         }
2710 
2711         return m;
2712     }
2713 
2714     void validateMethodType(Name name, Type t) {
2715         if ((!t.hasTag(TypeTag.METHOD) && !t.hasTag(TypeTag.FORALL)) ||
2716             (name == names.init && !t.getReturnType().hasTag(TypeTag.VOID))) {
2717             throw badClassFile("method.descriptor.invalid", name);
2718         }
2719     }
2720 
2721     private List<Type> adjustMethodParams(long flags, List<Type> args) {
2722         if (args.isEmpty()) {
2723             return args;
2724         }
2725         boolean isVarargs = (flags & VARARGS) != 0;
2726         if (isVarargs) {
2727             Type varargsElem = args.last();
2728             ListBuffer<Type> adjustedArgs = new ListBuffer<>();
2729             for (Type t : args) {
2730                 adjustedArgs.append(t != varargsElem ?
2731                     t :
2732                     ((ArrayType)t).makeVarargs());
2733             }
2734             args = adjustedArgs.toList();
2735         }
2736         return args.tail;
2737     }
2738 
2739     /**
2740      * Init the parameter names array.
2741      * Parameter names are currently inferred from the names in the
2742      * LocalVariableTable attributes of a Code attribute.
2743      * (Note: this means parameter names are currently not available for
2744      * methods without a Code attribute.)
2745      * This method initializes an array in which to store the name indexes
2746      * of parameter names found in LocalVariableTable attributes. It is
2747      * slightly supersized to allow for additional slots with a start_pc of 0.
2748      */
2749     void initParameterNames(MethodSymbol sym) {
2750         // make allowance for synthetic parameters.
2751         final int excessSlots = 4;
2752         int expectedParameterSlots =
2753                 Code.width(sym.type.getParameterTypes()) + excessSlots;
2754         if (parameterNameIndicesLvt == null
2755                 || parameterNameIndicesLvt.length < expectedParameterSlots) {
2756             parameterNameIndicesLvt = new int[expectedParameterSlots];
2757         } else
2758             Arrays.fill(parameterNameIndicesLvt, 0);
2759     }
2760 
2761     /**
2762      * Set the parameters for a method symbol, including any names and
2763      * annotations that were read.
2764      *
2765      * <p>The type of the symbol may have changed while reading the
2766      * method attributes (see the Signature attribute). This may be
2767      * because of generic information or because anonymous synthetic
2768      * parameters were added.   The original type (as read from the
2769      * method descriptor) is used to help guess the existence of
2770      * anonymous synthetic parameters.
2771      */
2772     void setParameters(MethodSymbol sym, Type jvmType) {
2773         int firstParamLvt = ((sym.flags() & STATIC) == 0) ? 1 : 0;
2774         // the code in readMethod may have skipped the first
2775         // parameter when setting up the MethodType. If so, we
2776         // make a corresponding allowance here for the position of
2777         // the first parameter.  Note that this assumes the
2778         // skipped parameter has a width of 1 -- i.e. it is not
2779         // a double width type (long or double.)
2780         if (sym.name == names.init && currentOwner.hasOuterInstance()) {
2781             // Sometimes anonymous classes don't have an outer
2782             // instance, however, there is no reliable way to tell so
2783             // we never strip this$n
2784             if (!currentOwner.name.isEmpty())
2785                 firstParamLvt += 1;
2786         }
2787 
2788         if (sym.type != jvmType) {
2789             // reading the method attributes has caused the
2790             // symbol's type to be changed. (i.e. the Signature
2791             // attribute.)  This may happen if there are hidden
2792             // (synthetic) parameters in the descriptor, but not
2793             // in the Signature.  The position of these hidden
2794             // parameters is unspecified; for now, assume they are
2795             // at the beginning, and so skip over them. The
2796             // primary case for this is two hidden parameters
2797             // passed into Enum constructors.
2798             int skip = Code.width(jvmType.getParameterTypes())
2799                     - Code.width(sym.type.getParameterTypes());
2800             firstParamLvt += skip;
2801         }
2802         Set<Name> paramNames = new HashSet<>();
2803         ListBuffer<VarSymbol> params = new ListBuffer<>();
2804         // we maintain two index pointers, one for the LocalVariableTable attribute
2805         // and the other for the MethodParameters attribute.
2806         // This is needed as the MethodParameters attribute may contain
2807         // name_index = 0 in which case we want to fall back to the LocalVariableTable.
2808         // In such case, we still want to read the flags from the MethodParameters with that index.
2809         int nameIndexLvt = firstParamLvt;
2810         int nameIndexMp = 0;
2811         int annotationIndex = 0;
2812         for (Type t: sym.type.getParameterTypes()) {
2813             VarSymbol param = parameter(nameIndexMp, nameIndexLvt, t, sym, paramNames);
2814             params.append(param);
2815             if (parameterAnnotations != null) {
2816                 ParameterAnnotations annotations = parameterAnnotations[annotationIndex];
2817                 if (annotations != null && annotations.proxies != null
2818                         && !annotations.proxies.isEmpty()) {
2819                     annotate.normal(new AnnotationCompleter(param, annotations.proxies));
2820                 }
2821             }
2822             nameIndexLvt += Code.width(t);
2823             nameIndexMp++;
2824             annotationIndex++;
2825         }
2826         Assert.check(parameterAnnotations == null ||
2827                      parameterAnnotations.length == annotationIndex);
2828         Assert.checkNull(sym.params);
2829         sym.params = params.toList();
2830         parameterAnnotations = null;
2831         parameterNameIndicesLvt = null;
2832         parameterNameIndicesMp = null;
2833         allParameterAccessFlags = null;
2834         parameterAccessFlags = null;
2835     }
2836 
2837     void adjustParameterAnnotations(MethodSymbol sym, Type methodDescriptor,
2838                                     boolean forceLocal) {
2839         if (parameterAnnotations == null) {
2840             return ;
2841         }
2842 
2843         //the specification for Runtime(In)VisibleParameterAnnotations does not
2844         //enforce any mapping between the method parameters and the recorded
2845         //parameter annotation. Attempt a number of heuristics to adjust the
2846         //adjust parameterAnnotations to the percieved number of parameters:
2847 
2848         int methodParameterCount = sym.type.getParameterTypes().size();
2849 
2850         if (methodParameterCount == parameterAnnotations.length) {
2851             //we've got exactly as many parameter annotations as are parameters
2852             //of the method (after considering a possible Signature attribute),
2853             //no need to do anything. the parameter creation code will use
2854             //the 1-1 mapping to restore the annotations:
2855             return ;
2856         }
2857 
2858         if (allParameterAccessFlags != null) {
2859             //MethodParameters attribute present, use it:
2860 
2861             //count the number of non-synthetic and non-mandatory parameters:
2862             int realParameters = 0;
2863 
2864             for (int i = 0; i < allParameterAccessFlags.length; i++) {
2865                 if ((allParameterAccessFlags[i] & (SYNTHETIC | MANDATED)) == 0) {
2866                     realParameters++;
2867                 }
2868             }
2869 
2870             int methodDescriptorParameterCount = methodDescriptor.getParameterTypes().size();
2871 
2872             if (realParameters == parameterAnnotations.length &&
2873                 allParameterAccessFlags.length == methodDescriptorParameterCount) {
2874                 //if we have parameter annotations for each non-synthetic/mandatory parameter,
2875                 //and if Signature was not present, expand the parameterAnnotations to cover
2876                 //all the method descriptor's parameters:
2877                 if (sym.type == methodDescriptor) {
2878                     ParameterAnnotations[] newParameterAnnotations =
2879                             new ParameterAnnotations[methodParameterCount];
2880                     int srcIndex = 0;
2881 
2882                     for (int i = 0; i < methodParameterCount; i++) {
2883                         if ((allParameterAccessFlags[i] & (SYNTHETIC | MANDATED)) == 0) {
2884                             newParameterAnnotations[i] = parameterAnnotations[srcIndex++];
2885                         }
2886                     }
2887 
2888                     parameterAnnotations = newParameterAnnotations;
2889                 } else {
2890                     dropParameterAnnotations();
2891                 }
2892             } else if (realParameters == methodParameterCount &&
2893                        methodDescriptorParameterCount == parameterAnnotations.length &&
2894                        allParameterAccessFlags.length == methodDescriptorParameterCount) {
2895                 //if there are as many parameter annotations as parameters in
2896                 //the method descriptor, and as many real parameters as parameters
2897                 //in the method's type (after accounting for Signature), shrink
2898                 //the parameterAnnotations to only cover the parameters from
2899                 //the method's type:
2900                 ParameterAnnotations[] newParameterAnnotations =
2901                         new ParameterAnnotations[methodParameterCount];
2902                 int targetIndex = 0;
2903 
2904                 for (int i = 0; i < parameterAnnotations.length; i++) {
2905                     if ((allParameterAccessFlags[i] & (SYNTHETIC | MANDATED)) == 0) {
2906                         newParameterAnnotations[targetIndex++] = parameterAnnotations[i];
2907                     }
2908                 }
2909 
2910                 parameterAnnotations = newParameterAnnotations;
2911             } else {
2912                 dropParameterAnnotations();
2913             }
2914             return ;
2915         }
2916 
2917         if (!sym.isConstructor()) {
2918             //if the number of parameter annotations and the number of parameters
2919             //don't match, we don't have any heuristics to map one to the other
2920             //unless the method is a constructor:
2921             dropParameterAnnotations();
2922             return ;
2923         }
2924 
2925         if (sym.owner.isEnum()) {
2926             if (methodParameterCount == parameterAnnotations.length + 2 &&
2927                 sym.type == methodDescriptor) {
2928                 //handle constructors of enum types without the Signature attribute -
2929                 //there are the two synthetic parameters (name and ordinal) in the
2930                 //constructor, but there may be only parameter annotations for the
2931                 //real non-synthetic parameters:
2932                 ParameterAnnotations[] newParameterAnnotations = new ParameterAnnotations[parameterAnnotations.length + 2];
2933                 System.arraycopy(parameterAnnotations, 0, newParameterAnnotations, 2, parameterAnnotations.length);
2934                 parameterAnnotations = newParameterAnnotations;
2935                 return ;
2936             }
2937         } else if (sym.owner.isDirectlyOrIndirectlyLocal() || forceLocal) {
2938             //local class may capture the enclosing instance (as the first parameter),
2939             //and local variables (as trailing parameters)
2940             //if there are less parameter annotations than parameters, put the existing
2941             //ones starting with offset:
2942             if (methodParameterCount > parameterAnnotations.length &&
2943                 sym.type == methodDescriptor) {
2944                 ParameterAnnotations[] newParameterAnnotations = new ParameterAnnotations[methodParameterCount];
2945                 System.arraycopy(parameterAnnotations, 0, newParameterAnnotations, 1, parameterAnnotations.length);
2946                 parameterAnnotations = newParameterAnnotations;
2947                 return ;
2948             }
2949         }
2950 
2951         //no heuristics worked, drop the annotations:
2952         dropParameterAnnotations();
2953     }
2954 
2955     private void dropParameterAnnotations() {
2956         parameterAnnotations = null;
2957         if (lintClassfile) {
2958             log.warning(LintCategory.CLASSFILE, Warnings.RuntimeInvisibleParameterAnnotations(currentClassFile));
2959         }
2960     }
2961     /**
2962      * Creates the parameter at the position {@code mpIndex} in the parameter list of the owning method.
2963      * Flags are optionally read from the MethodParameters attribute.
2964      * Names are optionally read from the MethodParameters attribute. If the constant pool index
2965      * of the name is 0, then the name is optionally read from the LocalVariableTable attribute.
2966      * @param mpIndex the index of the parameter in the MethodParameters attribute
2967      * @param lvtIndex the index of the parameter in the LocalVariableTable attribute
2968      */
2969     private VarSymbol parameter(int mpIndex, int lvtIndex, Type t, MethodSymbol owner, Set<Name> exclude) {
2970         long flags = PARAMETER;
2971         Name argName;
2972         if (parameterAccessFlags != null && mpIndex < parameterAccessFlags.length
2973                 && parameterAccessFlags[mpIndex] != 0) {
2974             flags |= parameterAccessFlags[mpIndex];
2975         }
2976         if (parameterNameIndicesMp != null && mpIndex < parameterNameIndicesMp.length
2977                 // if name_index is 0, then we might still get a name from the LocalVariableTable
2978                 && parameterNameIndicesMp[mpIndex] != 0) {
2979             argName = optPoolEntry(parameterNameIndicesMp[mpIndex], poolReader::getName, names.empty);
2980             flags |= NAME_FILLED;
2981         } else if (parameterNameIndicesLvt != null && lvtIndex < parameterNameIndicesLvt.length
2982                 && parameterNameIndicesLvt[lvtIndex] != 0) {
2983             argName = optPoolEntry(parameterNameIndicesLvt[lvtIndex], poolReader::getName, names.empty);
2984             flags |= NAME_FILLED;
2985         } else {
2986             String prefix = "arg";
2987             while (true) {
2988                 argName = names.fromString(prefix + exclude.size());
2989                 if (!exclude.contains(argName))
2990                     break;
2991                 prefix += "$";
2992             }
2993         }
2994         exclude.add(argName);
2995         return new ParamSymbol(flags, argName, t, owner);
2996     }
2997 
2998     /**
2999      * skip n bytes
3000      */
3001     void skipBytes(int n) {
3002         bp = bp + n;
3003     }
3004 
3005     /** Skip a field or method
3006      */
3007     void skipMember() {
3008         bp = bp + 6;
3009         char ac = nextChar();
3010         for (int i = 0; i < ac; i++) {
3011             bp = bp + 2;
3012             int attrLen = nextInt();
3013             bp = bp + attrLen;
3014         }
3015     }
3016 
3017     void skipInnerClasses() {
3018         int n = nextChar();
3019         for (int i = 0; i < n; i++) {
3020             nextChar();
3021             nextChar();
3022             nextChar();
3023             nextChar();
3024         }
3025     }
3026 
3027     /** Enter type variables of this classtype and all enclosing ones in
3028      *  `typevars'.
3029      */
3030     protected void enterTypevars(Symbol sym, Type t) {
3031         if (t.getEnclosingType() != null) {
3032             if (!t.getEnclosingType().hasTag(TypeTag.NONE)) {
3033                 enterTypevars(sym.owner, t.getEnclosingType());
3034             }
3035         } else if (sym.kind == MTH && !sym.isStatic()) {
3036             enterTypevars(sym.owner, sym.owner.type);
3037         }
3038         for (List<Type> xs = t.getTypeArguments(); xs.nonEmpty(); xs = xs.tail) {
3039             typevars.enter(xs.head.tsym);
3040         }
3041     }
3042 
3043     protected ClassSymbol enterClass(Name name) {
3044         return syms.enterClass(currentModule, name);
3045     }
3046 
3047     protected ClassSymbol enterClass(Name name, TypeSymbol owner) {
3048         return syms.enterClass(currentModule, name, owner);
3049     }
3050 
3051     /** Read contents of a given class symbol `c'. Both external and internal
3052      *  versions of an inner class are read.
3053      */
3054     void readClass(ClassSymbol c) {
3055         ClassType ct = (ClassType)c.type;
3056 
3057         // allocate scope for members
3058         c.members_field = WriteableScope.create(c);
3059 
3060         // prepare type variable table
3061         typevars = typevars.dup(currentOwner);
3062         if (ct.getEnclosingType().hasTag(CLASS))
3063             enterTypevars(c.owner, ct.getEnclosingType());
3064 
3065         // read flags, or skip if this is an inner class
3066         long f = nextChar();
3067         long flags = adjustClassFlags(f);
3068         if ((flags & MODULE) == 0) {
3069             if (c.owner.kind == PCK || c.owner.kind == ERR) c.flags_field = flags;
3070             // read own class name and check that it matches
3071             currentModule = c.packge().modle;
3072             ClassSymbol self = poolReader.getClass(nextChar());
3073             if (c != self) {
3074                 throw badClassFile("class.file.wrong.class",
3075                                    self.flatname);
3076             }
3077         } else {
3078             if (majorVersion < Version.V53.major) {
3079                 throw badClassFile("anachronistic.module.info",
3080                         Integer.toString(majorVersion),
3081                         Integer.toString(minorVersion));
3082             }
3083             c.flags_field = flags;
3084             if (c.owner.kind != MDL) {
3085                 throw badClassFile("module.info.definition.expected");
3086             }
3087             currentModule = (ModuleSymbol) c.owner;
3088             int this_class = nextChar();
3089             // temp, no check on this_class
3090         }
3091 
3092         // class attributes must be read before class
3093         // skip ahead to read class attributes
3094         int startbp = bp;
3095         nextChar();
3096         char interfaceCount = nextChar();
3097         bp += interfaceCount * 2;
3098         char fieldCount = nextChar();
3099         for (int i = 0; i < fieldCount; i++) skipMember();
3100         char methodCount = nextChar();
3101         for (int i = 0; i < methodCount; i++) skipMember();
3102         readClassAttrs(c);
3103 
3104         if (!c.getPermittedSubclasses().isEmpty()) {
3105             c.flags_field |= SEALED;
3106         }
3107 
3108         // reset and read rest of classinfo
3109         bp = startbp;
3110         int n = nextChar();
3111         if ((flags & MODULE) != 0 && n > 0) {
3112             throw badClassFile("module.info.invalid.super.class");
3113         }
3114         if (ct.supertype_field == null)
3115             ct.supertype_field =
3116                     optPoolEntry(n, idx -> poolReader.getClass(idx).erasure(types), Type.noType);
3117         n = nextChar();
3118         List<Type> is = List.nil();
3119         for (int i = 0; i < n; i++) {
3120             Type _inter = poolReader.getClass(nextChar()).erasure(types);
3121             is = is.prepend(_inter);
3122         }
3123         if (ct.interfaces_field == null)
3124             ct.interfaces_field = is.reverse();
3125 
3126         Assert.check(fieldCount == nextChar());
3127         for (int i = 0; i < fieldCount; i++) enterMember(c, readField());
3128         Assert.check(methodCount == nextChar());
3129         for (int i = 0; i < methodCount; i++) enterMember(c, readMethod());
3130         if (c.isRecord()) {
3131             for (RecordComponent rc: c.getRecordComponents()) {
3132                 rc.accessor = lookupMethod(c, rc.name, List.nil());
3133             }
3134         }
3135         typevars = typevars.leave();
3136     }
3137 
3138     private MethodSymbol lookupMethod(TypeSymbol tsym, Name name, List<Type> argtypes) {
3139         for (Symbol s : tsym.members().getSymbolsByName(name, s -> s.kind == MTH)) {
3140             if (types.isSameTypes(s.type.getParameterTypes(), argtypes)) {
3141                 return (MethodSymbol) s;
3142             }
3143         }
3144         return null;
3145     }
3146 
3147     /** Read inner class info. For each inner/outer pair allocate a
3148      *  member class.
3149      */
3150     void readInnerClasses(ClassSymbol c) {
3151         int n = nextChar();
3152         for (int i = 0; i < n; i++) {
3153             nextChar(); // skip inner class symbol
3154             int outerIdx = nextChar();
3155             int nameIdx = nextChar();
3156             ClassSymbol outer = optPoolEntry(outerIdx, poolReader::getClass, null);
3157             Name name = optPoolEntry(nameIdx, poolReader::getName, names.empty);
3158             if (name == null) name = names.empty;
3159             long flags = adjustClassFlags(nextChar());
3160             if (outer != null) { // we have a member class
3161                 if (name == names.empty)
3162                     name = names.one;
3163                 ClassSymbol member = enterClass(name, outer);
3164                 if ((flags & STATIC) == 0) {
3165                     ((ClassType)member.type).setEnclosingType(outer.type);
3166                     if (member.erasure_field != null)
3167                         ((ClassType)member.erasure_field).setEnclosingType(types.erasure(outer.type));
3168                 }
3169                 if (c == outer && member.owner == c) {
3170                     member.flags_field = flags;
3171                     enterMember(c, member);
3172                 }
3173             }
3174         }
3175     }
3176 
3177     /** Read a class definition from the bytes in buf.
3178      */
3179     private void readClassBuffer(ClassSymbol c) throws IOException {
3180         int magic = nextInt();
3181         if (magic != JAVA_MAGIC)
3182             throw badClassFile("illegal.start.of.class.file");
3183 
3184         minorVersion = nextChar();
3185         majorVersion = nextChar();
3186         int maxMajor = Version.MAX().major;
3187         int maxMinor = Version.MAX().minor;
3188         boolean previewClassFile =
3189                 minorVersion == ClassFile.PREVIEW_MINOR_VERSION;
3190         if (majorVersion > maxMajor ||
3191             majorVersion * 1000 + minorVersion <
3192             Version.MIN().major * 1000 + Version.MIN().minor) {
3193             if (majorVersion == (maxMajor + 1) && !previewClassFile)
3194                 log.warning(Warnings.BigMajorVersion(currentClassFile,
3195                                                      majorVersion,
3196                                                      maxMajor));
3197             else
3198                 throw badClassFile("wrong.version",
3199                                    Integer.toString(majorVersion),
3200                                    Integer.toString(minorVersion),
3201                                    Integer.toString(maxMajor),
3202                                    Integer.toString(maxMinor));
3203         }
3204         utf8validation = majorVersion < V48.major ? Convert.Validation.PREJDK14 : Convert.Validation.STRICT;
3205 
3206         if (previewClassFile) {
3207             if (!preview.isEnabled()) {
3208                 log.error(preview.disabledError(currentClassFile, majorVersion));
3209             } else {
3210                 preview.warnPreview(c.classfile, majorVersion);
3211             }
3212         }
3213 
3214         poolReader = new PoolReader(this, names, syms);
3215         bp = poolReader.readPool(buf, bp);
3216         if (signatureBuffer.length < bp) {
3217             int ns = Integer.highestOneBit(bp) << 1;
3218             signatureBuffer = new byte[ns];
3219         }
3220         readClass(c);
3221     }
3222 
3223     public void readClassFile(ClassSymbol c) {
3224         currentOwner = c;
3225         currentClassFile = c.classfile;
3226         warnedAttrs.clear();
3227         filling = true;
3228         target = null;
3229         repeatable = null;
3230         try {
3231             bp = 0;
3232             buf.reset();
3233             try (InputStream input = c.classfile.openInputStream()) {
3234                 buf.appendStream(input);
3235             }
3236             readClassBuffer(c);
3237             if (!missingTypeVariables.isEmpty() && !foundTypeVariables.isEmpty()) {
3238                 List<Type> missing = missingTypeVariables;
3239                 List<Type> found = foundTypeVariables;
3240                 missingTypeVariables = List.nil();
3241                 foundTypeVariables = List.nil();
3242                 interimUses = List.nil();
3243                 interimProvides = List.nil();
3244                 filling = false;
3245                 ClassType ct = (ClassType)currentOwner.type;
3246                 ct.supertype_field =
3247                     types.subst(ct.supertype_field, missing, found);
3248                 ct.interfaces_field =
3249                     types.subst(ct.interfaces_field, missing, found);
3250                 ct.typarams_field =
3251                     types.substBounds(ct.typarams_field, missing, found);
3252                 for (List<Type> types = ct.typarams_field; types.nonEmpty(); types = types.tail) {
3253                     types.head.tsym.type = types.head;
3254                 }
3255             } else if (missingTypeVariables.isEmpty() !=
3256                        foundTypeVariables.isEmpty()) {
3257                 Name name = missingTypeVariables.head.tsym.name;
3258                 throw badClassFile("undecl.type.var", name);
3259             }
3260 
3261             if ((c.flags_field & Flags.ANNOTATION) != 0) {
3262                 c.setAnnotationTypeMetadata(new AnnotationTypeMetadata(c, new CompleterDeproxy(c, target, repeatable)));
3263             } else {
3264                 c.setAnnotationTypeMetadata(AnnotationTypeMetadata.notAnAnnotationType());
3265             }
3266 
3267             if (c == currentModule.module_info) {
3268                 if (interimUses.nonEmpty() || interimProvides.nonEmpty()) {
3269                     Assert.check(currentModule.isCompleted());
3270                     currentModule.usesProvidesCompleter =
3271                             new UsesProvidesCompleter(currentModule, interimUses, interimProvides);
3272                 } else {
3273                     currentModule.uses = List.nil();
3274                     currentModule.provides = List.nil();
3275                 }
3276             }
3277         } catch (IOException | ClosedFileSystemException ex) {
3278             throw badClassFile("unable.to.access.file", ex.toString());
3279         } catch (ArrayIndexOutOfBoundsException ex) {
3280             throw badClassFile("bad.class.file", c.flatname);
3281         } finally {
3282             interimUses = List.nil();
3283             interimProvides = List.nil();
3284             missingTypeVariables = List.nil();
3285             foundTypeVariables = List.nil();
3286             filling = false;
3287         }
3288     }
3289 
3290     /** We can only read a single class file at a time; this
3291      *  flag keeps track of when we are currently reading a class
3292      *  file.
3293      */
3294     public boolean filling = false;
3295 
3296 /* **********************************************************************
3297  * Adjusting flags
3298  ***********************************************************************/
3299 
3300     long adjustFieldFlags(long flags) {
3301         return flags;
3302     }
3303 
3304     long adjustMethodFlags(long flags) {
3305         if ((flags & ACC_BRIDGE) != 0) {
3306             flags &= ~ACC_BRIDGE;
3307             flags |= BRIDGE;
3308         }
3309         if ((flags & ACC_VARARGS) != 0) {
3310             flags &= ~ACC_VARARGS;
3311             flags |= VARARGS;
3312         }
3313         return flags;
3314     }
3315 
3316     long adjustClassFlags(long flags) {
3317         if ((flags & ACC_MODULE) != 0) {
3318             flags &= ~ACC_MODULE;
3319             flags |= MODULE;
3320         }
3321         return flags & ~ACC_SUPER; // SUPER and SYNCHRONIZED bits overloaded
3322     }
3323 
3324     /**
3325      * A subclass of JavaFileObject for the sourcefile attribute found in a classfile.
3326      * The attribute is only the last component of the original filename, so is unlikely
3327      * to be valid as is, so operations other than those to access the name throw
3328      * UnsupportedOperationException
3329      */
3330     private static class SourceFileObject implements JavaFileObject {
3331 
3332         /** The file's name.
3333          */
3334         private final Name name;
3335 
3336         public SourceFileObject(Name name) {
3337             this.name = name;
3338         }
3339 
3340         @Override @DefinedBy(Api.COMPILER)
3341         public URI toUri() {
3342             try {
3343                 return new URI(null, name.toString(), null);
3344             } catch (URISyntaxException e) {
3345                 throw new PathFileObject.CannotCreateUriError(name.toString(), e);
3346             }
3347         }
3348 
3349         @Override @DefinedBy(Api.COMPILER)
3350         public String getName() {
3351             return name.toString();
3352         }
3353 
3354         @Override @DefinedBy(Api.COMPILER)
3355         public JavaFileObject.Kind getKind() {
3356             return BaseFileManager.getKind(getName());
3357         }
3358 
3359         @Override @DefinedBy(Api.COMPILER)
3360         public InputStream openInputStream() {
3361             throw new UnsupportedOperationException();
3362         }
3363 
3364         @Override @DefinedBy(Api.COMPILER)
3365         public OutputStream openOutputStream() {
3366             throw new UnsupportedOperationException();
3367         }
3368 
3369         @Override @DefinedBy(Api.COMPILER)
3370         public CharBuffer getCharContent(boolean ignoreEncodingErrors) {
3371             throw new UnsupportedOperationException();
3372         }
3373 
3374         @Override @DefinedBy(Api.COMPILER)
3375         public Reader openReader(boolean ignoreEncodingErrors) {
3376             throw new UnsupportedOperationException();
3377         }
3378 
3379         @Override @DefinedBy(Api.COMPILER)
3380         public Writer openWriter() {
3381             throw new UnsupportedOperationException();
3382         }
3383 
3384         @Override @DefinedBy(Api.COMPILER)
3385         public long getLastModified() {
3386             throw new UnsupportedOperationException();
3387         }
3388 
3389         @Override @DefinedBy(Api.COMPILER)
3390         public boolean delete() {
3391             throw new UnsupportedOperationException();
3392         }
3393 
3394         @Override @DefinedBy(Api.COMPILER)
3395         public boolean isNameCompatible(String simpleName, JavaFileObject.Kind kind) {
3396             return true; // fail-safe mode
3397         }
3398 
3399         @Override @DefinedBy(Api.COMPILER)
3400         public NestingKind getNestingKind() {
3401             return null;
3402         }
3403 
3404         @Override @DefinedBy(Api.COMPILER)
3405         public Modifier getAccessLevel() {
3406             return null;
3407         }
3408 
3409         /**
3410          * Check if two file objects are equal.
3411          * SourceFileObjects are just placeholder objects for the value of a
3412          * SourceFile attribute, and do not directly represent specific files.
3413          * Two SourceFileObjects are equal if their names are equal.
3414          */
3415         @Override
3416         public boolean equals(Object other) {
3417             if (this == other)
3418                 return true;
3419             return (other instanceof SourceFileObject sourceFileObject)
3420                     && name.equals(sourceFileObject.name);
3421         }
3422 
3423         @Override
3424         public int hashCode() {
3425             return name.hashCode();
3426         }
3427     }
3428 
3429     private class CompleterDeproxy implements AnnotationTypeCompleter {
3430         ClassSymbol proxyOn;
3431         CompoundAnnotationProxy target;
3432         CompoundAnnotationProxy repeatable;
3433 
3434         public CompleterDeproxy(ClassSymbol c, CompoundAnnotationProxy target,
3435                 CompoundAnnotationProxy repeatable)
3436         {
3437             this.proxyOn = c;
3438             this.target = target;
3439             this.repeatable = repeatable;
3440         }
3441 
3442         @Override
3443         public void complete(ClassSymbol sym) {
3444             Assert.check(proxyOn == sym);
3445             Attribute.Compound theTarget = null, theRepeatable = null;
3446             AnnotationDeproxy deproxy;
3447 
3448             try {
3449                 if (target != null) {
3450                     deproxy = new AnnotationDeproxy(proxyOn);
3451                     theTarget = deproxy.deproxyCompound(target);
3452                 }
3453 
3454                 if (repeatable != null) {
3455                     deproxy = new AnnotationDeproxy(proxyOn);
3456                     theRepeatable = deproxy.deproxyCompound(repeatable);
3457                 }
3458             } catch (Exception e) {
3459                 throw new CompletionFailure(sym,
3460                                             () -> ClassReader.this.diagFactory.fragment(Fragments.ExceptionMessage(e.getMessage())),
3461                                             dcfh);
3462             }
3463 
3464             sym.getAnnotationTypeMetadata().setTarget(theTarget);
3465             sym.getAnnotationTypeMetadata().setRepeatable(theRepeatable);
3466         }
3467     }
3468 
3469     private class ProxyType extends Type {
3470 
3471         private final Name name;
3472 
3473         public ProxyType(int index) {
3474             super(syms.noSymbol, List.nil());
3475             this.name = poolReader.getName(index);
3476         }
3477 
3478         @Override
3479         public TypeTag getTag() {
3480             return TypeTag.NONE;
3481         }
3482 
3483         public Type resolve() {
3484             return name.map(ClassReader.this::sigToType);
3485         }
3486 
3487         @Override @DefinedBy(Api.LANGUAGE_MODEL)
3488         public String toString() {
3489             return "<ProxyType>";
3490         }
3491 
3492     }
3493 
3494     private static final class InterimUsesDirective {
3495         public final Name service;
3496 
3497         public InterimUsesDirective(Name service) {
3498             this.service = service;
3499         }
3500 
3501     }
3502 
3503     private static final class InterimProvidesDirective {
3504         public final Name service;
3505         public final List<Name> impls;
3506 
3507         public InterimProvidesDirective(Name service, List<Name> impls) {
3508             this.service = service;
3509             this.impls = impls;
3510         }
3511 
3512     }
3513 
3514     private final class UsesProvidesCompleter implements Completer {
3515         private final ModuleSymbol currentModule;
3516         private final List<InterimUsesDirective> interimUsesCopy;
3517         private final List<InterimProvidesDirective> interimProvidesCopy;
3518 
3519         public UsesProvidesCompleter(ModuleSymbol currentModule, List<InterimUsesDirective> interimUsesCopy, List<InterimProvidesDirective> interimProvidesCopy) {
3520             this.currentModule = currentModule;
3521             this.interimUsesCopy = interimUsesCopy;
3522             this.interimProvidesCopy = interimProvidesCopy;
3523         }
3524 
3525         @Override
3526         public void complete(Symbol sym) throws CompletionFailure {
3527             ListBuffer<Directive> directives = new ListBuffer<>();
3528             directives.addAll(currentModule.directives);
3529             ListBuffer<UsesDirective> uses = new ListBuffer<>();
3530             for (InterimUsesDirective interim : interimUsesCopy) {
3531                 UsesDirective d = new UsesDirective(syms.enterClass(currentModule, interim.service));
3532                 uses.add(d);
3533                 directives.add(d);
3534             }
3535             currentModule.uses = uses.toList();
3536             ListBuffer<ProvidesDirective> provides = new ListBuffer<>();
3537             for (InterimProvidesDirective interim : interimProvidesCopy) {
3538                 ListBuffer<ClassSymbol> impls = new ListBuffer<>();
3539                 for (Name impl : interim.impls) {
3540                     impls.append(syms.enterClass(currentModule, impl));
3541                 }
3542                 ProvidesDirective d = new ProvidesDirective(syms.enterClass(currentModule, interim.service),
3543                                                             impls.toList());
3544                 provides.add(d);
3545                 directives.add(d);
3546             }
3547             currentModule.provides = provides.toList();
3548             currentModule.directives = directives.toList();
3549         }
3550     }
3551 }