1 /*
   2  * Copyright (c) 1999, 2025, 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.LintWarnings;
  68 import com.sun.tools.javac.resources.CompilerProperties.Warnings;
  69 import com.sun.tools.javac.util.*;
  70 import com.sun.tools.javac.util.ByteBuffer.UnderflowException;
  71 import com.sun.tools.javac.util.DefinedBy.Api;
  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     /** Switch: warn (instead of error) on illegal UTF-8
 123      */
 124     boolean warnOnIllegalUtf8;
 125 
 126     /** Switch: preserve parameter names from the variable table.
 127      */
 128     public boolean saveParameterNames;
 129 
 130     /**
 131      * The currently selected profile.
 132      */
 133     public final Profile profile;
 134 
 135     /** The log to use for verbose output
 136      */
 137     final Log log;
 138 
 139     /** The symbol table. */
 140     Symtab syms;
 141 
 142     /** The root Lint config. */
 143     Lint lint;
 144 
 145     Types types;
 146 
 147     /** The name table. */
 148     final Names names;
 149 
 150     /** Access to files
 151      */
 152     private final JavaFileManager fileManager;
 153 
 154     /** Factory for diagnostics
 155      */
 156     JCDiagnostic.Factory diagFactory;
 157 
 158     DeferredCompletionFailureHandler dcfh;
 159 
 160     /**
 161      * Support for preview language features.
 162      */
 163     Preview preview;
 164 
 165     /** The current scope where type variables are entered.
 166      */
 167     protected WriteableScope typevars;
 168 
 169     private List<InterimUsesDirective> interimUses = List.nil();
 170     private List<InterimProvidesDirective> interimProvides = List.nil();
 171 
 172     /** The path name of the class file currently being read.
 173      */
 174     protected JavaFileObject currentClassFile = null;
 175 
 176     /** The class or method currently being read.
 177      */
 178     protected Symbol currentOwner = null;
 179 
 180     /** The module containing the class currently being read.
 181      */
 182     protected ModuleSymbol currentModule = null;
 183 
 184     /** The buffer containing the currently read class file.
 185      */
 186     ByteBuffer buf = new ByteBuffer(INITIAL_BUFFER_SIZE);
 187 
 188     /** The current input pointer.
 189      */
 190     protected int bp;
 191 
 192     /** The pool reader.
 193      */
 194     PoolReader poolReader;
 195 
 196     /** The major version number of the class file being read. */
 197     int majorVersion;
 198     /** The minor version number of the class file being read. */
 199     int minorVersion;
 200 
 201     /** true if the class file being read is a preview class file. */
 202     boolean previewClassFile;
 203 
 204     /** UTF-8 validation level */
 205     Convert.Validation utf8validation;
 206 
 207     /** A table to hold the constant pool indices for method parameter
 208      * names, as given in LocalVariableTable attributes.
 209      */
 210     int[] parameterNameIndicesLvt;
 211 
 212     /**
 213      * A table to hold the constant pool indices for method parameter
 214      * names, as given in the MethodParameters attribute.
 215      */
 216     int[] parameterNameIndicesMp;
 217 
 218     /**
 219      * A table to hold the access flags of the method parameters.
 220      */
 221     int[] parameterAccessFlags;
 222 
 223     /**
 224      * A table to hold the access flags of the method parameters,
 225      * for all parameters including synthetic and mandated ones.
 226      */
 227     int[] allParameterAccessFlags;
 228 
 229     /**
 230      * A table to hold annotations for method parameters.
 231      */
 232     ParameterAnnotations[] parameterAnnotations;
 233 
 234     /**
 235      * A holder for parameter annotations.
 236      */
 237     static class ParameterAnnotations {
 238         List<CompoundAnnotationProxy> proxies;
 239 
 240         void add(List<CompoundAnnotationProxy> newAnnotations) {
 241             if (proxies == null) {
 242                 proxies = newAnnotations;
 243             } else {
 244                 proxies = proxies.prependList(newAnnotations);
 245             }
 246         }
 247     }
 248 
 249     /**
 250      * The set of attribute names for which warnings have been generated for the current class
 251      */
 252     Set<Name> warnedAttrs = new HashSet<>();
 253 
 254     /**
 255      * The prototype @Target Attribute.Compound if this class is an annotation annotated with
 256      * {@code @Target}
 257      */
 258     CompoundAnnotationProxy target;
 259 
 260     /**
 261      * The prototype @Repeatable Attribute.Compound if this class is an annotation annotated with
 262      * {@code @Repeatable}
 263      */
 264     CompoundAnnotationProxy repeatable;
 265 
 266     /** Get the ClassReader instance for this invocation. */
 267     public static ClassReader instance(Context context) {
 268         ClassReader instance = context.get(classReaderKey);
 269         if (instance == null)
 270             instance = new ClassReader(context);
 271         return instance;
 272     }
 273 
 274     /** Construct a new class reader. */
 275     @SuppressWarnings("this-escape")
 276     protected ClassReader(Context context) {
 277         context.put(classReaderKey, this);
 278         annotate = Annotate.instance(context);
 279         names = Names.instance(context);
 280         syms = Symtab.instance(context);
 281         types = Types.instance(context);
 282         fileManager = context.get(JavaFileManager.class);
 283         if (fileManager == null)
 284             throw new AssertionError("FileManager initialization error");
 285         diagFactory = JCDiagnostic.Factory.instance(context);
 286         dcfh = DeferredCompletionFailureHandler.instance(context);
 287 
 288         log = Log.instance(context);
 289 
 290         Options options = Options.instance(context);
 291         verbose         = options.isSet(Option.VERBOSE);
 292 
 293         Source source = Source.instance(context);
 294         preview = Preview.instance(context);
 295         allowModules     = Feature.MODULES.allowedInSource(source);
 296         allowRecords = Feature.RECORDS.allowedInSource(source);
 297         allowSealedTypes = Feature.SEALED_CLASSES.allowedInSource(source);
 298         warnOnIllegalUtf8 = Feature.WARN_ON_ILLEGAL_UTF8.allowedInSource(source);
 299 
 300         saveParameterNames = options.isSet(PARAMETERS);
 301 
 302         profile = Profile.instance(context);
 303 
 304         typevars = WriteableScope.create(syms.noSymbol);
 305 
 306         lint = Lint.instance(context);
 307 
 308         initAttributeReaders();
 309     }
 310 
 311     /** Add member to class unless it is synthetic.
 312      */
 313     private void enterMember(ClassSymbol c, Symbol sym) {
 314         // Synthetic members are not entered -- reason lost to history (optimization?).
 315         // Lambda methods must be entered because they may have inner classes (which reference them)
 316         if ((sym.flags_field & (SYNTHETIC|BRIDGE)) != SYNTHETIC || sym.name.startsWith(names.lambda))
 317             c.members_field.enter(sym);
 318     }
 319 
 320 /* **********************************************************************
 321  * Error Diagnoses
 322  ***********************************************************************/
 323 
 324     public ClassFinder.BadClassFile badClassFile(String key, Object... args) {
 325         return badClassFile(diagFactory.fragment(key, args));
 326     }
 327 
 328     public ClassFinder.BadClassFile badClassFile(Fragment fragment) {
 329         return badClassFile(diagFactory.fragment(fragment));
 330     }
 331 
 332     public ClassFinder.BadClassFile badClassFile(JCDiagnostic diagnostic) {
 333         return new ClassFinder.BadClassFile (
 334             currentOwner.enclClass(),
 335             currentClassFile,
 336             diagnostic,
 337             diagFactory,
 338             dcfh);
 339     }
 340 
 341     public ClassFinder.BadEnclosingMethodAttr badEnclosingMethod(Symbol sym) {
 342         return new ClassFinder.BadEnclosingMethodAttr (
 343             currentOwner.enclClass(),
 344             currentClassFile,
 345             diagFactory.fragment(Fragments.BadEnclosingMethod(sym)),
 346             diagFactory,
 347             dcfh);
 348     }
 349 
 350 /* **********************************************************************
 351  * Buffer Access
 352  ***********************************************************************/
 353 
 354     /** Read a character.
 355      */
 356     char nextChar() {
 357         char res;
 358         try {
 359             res = buf.getChar(bp);
 360         } catch (UnderflowException e) {
 361             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 362         }
 363         bp += 2;
 364         return res;
 365     }
 366 
 367     /** Read a byte.
 368      */
 369     int nextByte() {
 370         try {
 371             return buf.getByte(bp++) & 0xFF;
 372         } catch (UnderflowException e) {
 373             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 374         }
 375     }
 376 
 377     /** Read an integer.
 378      */
 379     int nextInt() {
 380         int res;
 381         try {
 382             res = buf.getInt(bp);
 383         } catch (UnderflowException e) {
 384             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
 385         }
 386         bp += 4;
 387         return res;
 388     }
 389 
 390 /* **********************************************************************
 391  * Constant Pool Access
 392  ***********************************************************************/
 393 
 394     /** Read module_flags.
 395      */
 396     Set<ModuleFlags> readModuleFlags(int flags) {
 397         Set<ModuleFlags> set = EnumSet.noneOf(ModuleFlags.class);
 398         for (ModuleFlags f : ModuleFlags.values()) {
 399             if ((flags & f.value) != 0)
 400                 set.add(f);
 401         }
 402         return set;
 403     }
 404 
 405     /** Read resolution_flags.
 406      */
 407     Set<ModuleResolutionFlags> readModuleResolutionFlags(int flags) {
 408         Set<ModuleResolutionFlags> set = EnumSet.noneOf(ModuleResolutionFlags.class);
 409         for (ModuleResolutionFlags f : ModuleResolutionFlags.values()) {
 410             if ((flags & f.value) != 0)
 411                 set.add(f);
 412         }
 413         return set;
 414     }
 415 
 416     /** Read exports_flags.
 417      */
 418     Set<ExportsFlag> readExportsFlags(int flags) {
 419         Set<ExportsFlag> set = EnumSet.noneOf(ExportsFlag.class);
 420         for (ExportsFlag f: ExportsFlag.values()) {
 421             if ((flags & f.value) != 0)
 422                 set.add(f);
 423         }
 424         return set;
 425     }
 426 
 427     /** Read opens_flags.
 428      */
 429     Set<OpensFlag> readOpensFlags(int flags) {
 430         Set<OpensFlag> set = EnumSet.noneOf(OpensFlag.class);
 431         for (OpensFlag f: OpensFlag.values()) {
 432             if ((flags & f.value) != 0)
 433                 set.add(f);
 434         }
 435         return set;
 436     }
 437 
 438     /** Read requires_flags.
 439      */
 440     Set<RequiresFlag> readRequiresFlags(int flags) {
 441         Set<RequiresFlag> set = EnumSet.noneOf(RequiresFlag.class);
 442         for (RequiresFlag f: RequiresFlag.values()) {
 443             if ((flags & f.value) != 0)
 444                 set.add(f);
 445         }
 446         return set;
 447     }
 448 
 449 /* **********************************************************************
 450  * Reading Types
 451  ***********************************************************************/
 452 
 453     /** The unread portion of the currently read type is
 454      *  signature[sigp..siglimit-1].
 455      */
 456     byte[] signature;
 457     int sigp;
 458     int siglimit;
 459     boolean sigEnterPhase = false;
 460 
 461     /** Convert signature to type, where signature is a byte array segment.
 462      */
 463     Type sigToType(byte[] sig, int offset, int len) {
 464         signature = sig;
 465         sigp = offset;
 466         siglimit = offset + len;
 467         return sigToType();
 468     }
 469 
 470     /** Convert signature to type, where signature is implicit.
 471      */
 472     Type sigToType() {
 473         switch ((char) signature[sigp]) {
 474         case 'T':
 475             sigp++;
 476             int start = sigp;
 477             while (signature[sigp] != ';') sigp++;
 478             sigp++;
 479             return sigEnterPhase
 480                 ? Type.noType
 481                 : findTypeVar(readName(signature, start, sigp - 1 - start));
 482         case '+': {
 483             sigp++;
 484             Type t = sigToType();
 485             return new WildcardType(t, BoundKind.EXTENDS, syms.boundClass);
 486         }
 487         case '*':
 488             sigp++;
 489             return new WildcardType(syms.objectType, BoundKind.UNBOUND,
 490                                     syms.boundClass);
 491         case '-': {
 492             sigp++;
 493             Type t = sigToType();
 494             return new WildcardType(t, BoundKind.SUPER, syms.boundClass);
 495         }
 496         case 'B':
 497             sigp++;
 498             return syms.byteType;
 499         case 'C':
 500             sigp++;
 501             return syms.charType;
 502         case 'D':
 503             sigp++;
 504             return syms.doubleType;
 505         case 'F':
 506             sigp++;
 507             return syms.floatType;
 508         case 'I':
 509             sigp++;
 510             return syms.intType;
 511         case 'J':
 512             sigp++;
 513             return syms.longType;
 514         case 'L':
 515             {
 516                 // int oldsigp = sigp;
 517                 Type t = classSigToType();
 518                 if (sigp < siglimit && signature[sigp] == '.')
 519                     throw badClassFile("deprecated inner class signature syntax " +
 520                                        "(please recompile from source)");
 521                 /*
 522                 System.err.println(" decoded " +
 523                                    new String(signature, oldsigp, sigp-oldsigp) +
 524                                    " => " + t + " outer " + t.outer());
 525                 */
 526                 return t;
 527             }
 528         case 'S':
 529             sigp++;
 530             return syms.shortType;
 531         case 'V':
 532             sigp++;
 533             return syms.voidType;
 534         case 'Z':
 535             sigp++;
 536             return syms.booleanType;
 537         case '[':
 538             sigp++;
 539             return new ArrayType(sigToType(), syms.arrayClass);
 540         case '(':
 541             sigp++;
 542             List<Type> argtypes = sigToTypes(')');
 543             Type restype = sigToType();
 544             List<Type> thrown = List.nil();
 545             while (sigp < siglimit && signature[sigp] == '^') {
 546                 sigp++;
 547                 thrown = thrown.prepend(sigToType());
 548             }
 549             // if there is a typevar in the throws clause we should state it.
 550             for (List<Type> l = thrown; l.nonEmpty(); l = l.tail) {
 551                 if (l.head.hasTag(TYPEVAR)) {
 552                     l.head.tsym.flags_field |= THROWS;
 553                 }
 554             }
 555             return new MethodType(argtypes,
 556                                   restype,
 557                                   thrown.reverse(),
 558                                   syms.methodClass);
 559         case '<':
 560             typevars = typevars.dup(currentOwner);
 561             Type poly = new ForAll(sigToTypeParams(), sigToType());
 562             typevars = typevars.leave();
 563             return poly;
 564         default:
 565             throw badClassFile("bad.signature", quoteBadSignature());
 566         }
 567     }
 568 
 569     byte[] signatureBuffer = new byte[0];
 570     int sbp = 0;
 571     /** Convert class signature to type, where signature is implicit.
 572      */
 573     Type classSigToType() {
 574         if (signature[sigp] != 'L')
 575             throw badClassFile("bad.class.signature", quoteBadSignature());
 576         sigp++;
 577         Type outer = Type.noType;
 578         int startSbp = sbp;
 579 
 580         while (true) {
 581             final byte c = signature[sigp++];
 582             switch (c) {
 583 
 584             case ';': {         // end
 585                 ClassSymbol t = enterClass(readName(signatureBuffer,
 586                                                          startSbp,
 587                                                          sbp - startSbp));
 588 
 589                 try {
 590                     return (outer == Type.noType) ?
 591                             t.erasure(types) :
 592                         new ClassType(outer, List.nil(), t);
 593                 } finally {
 594                     sbp = startSbp;
 595                 }
 596             }
 597 
 598             case '<':           // generic arguments
 599                 ClassSymbol t = enterClass(readName(signatureBuffer,
 600                                                          startSbp,
 601                                                          sbp - startSbp));
 602                 List<Type> actuals = sigToTypes('>');
 603                 List<Type> formals = ((ClassType)t.type.tsym.type).typarams_field;
 604                 if (formals != null) {
 605                     if (actuals.isEmpty())
 606                         actuals = formals;
 607                 }
 608                 /* actualsCp is final as it will be captured by the inner class below. We could avoid defining
 609                  * this additional local variable and depend on field ClassType::typarams_field which `actuals` is
 610                  * assigned to but then we would have a dependendy on the internal representation of ClassType which
 611                  * could change in the future
 612                  */
 613                 final List<Type> actualsCp = actuals;
 614                 outer = new ClassType(outer, actuals, t) {
 615                         boolean completed = false;
 616                         boolean typeArgsSet = false;
 617                         @Override @DefinedBy(Api.LANGUAGE_MODEL)
 618                         public Type getEnclosingType() {
 619                             if (!completed) {
 620                                 completed = true;
 621                                 tsym.apiComplete();
 622                                 Type enclosingType = tsym.type.getEnclosingType();
 623                                 if (enclosingType != Type.noType) {
 624                                     List<Type> typeArgs =
 625                                         super.getEnclosingType().allparams();
 626                                     List<Type> typeParams =
 627                                         enclosingType.allparams();
 628                                     if (typeParams.length() != typeArgs.length()) {
 629                                         // no "rare" types
 630                                         super.setEnclosingType(types.erasure(enclosingType));
 631                                     } else {
 632                                         super.setEnclosingType(types.subst(enclosingType,
 633                                                                            typeParams,
 634                                                                            typeArgs));
 635                                     }
 636                                 } else {
 637                                     super.setEnclosingType(Type.noType);
 638                                 }
 639                             }
 640                             return super.getEnclosingType();
 641                         }
 642                         @Override
 643                         public void setEnclosingType(Type outer) {
 644                             throw new UnsupportedOperationException();
 645                         }
 646 
 647                         @Override
 648                         public List<Type> getTypeArguments() {
 649                             if (!typeArgsSet) {
 650                                 typeArgsSet = true;
 651                                 List<Type> formalsCp = ((ClassType)t.type.tsym.type).typarams_field;
 652                                 if (formalsCp != null && !formalsCp.isEmpty()) {
 653                                     if (actualsCp.length() == formalsCp.length()) {
 654                                         List<Type> a = actualsCp;
 655                                         List<Type> f = formalsCp;
 656                                         while (a.nonEmpty()) {
 657                                             a.head = a.head.withTypeVar(f.head);
 658                                             a = a.tail;
 659                                             f = f.tail;
 660                                         }
 661                                     }
 662                                 }
 663                             }
 664                             return super.getTypeArguments();
 665                         }
 666                 };
 667                 switch (signature[sigp++]) {
 668                 case ';':
 669                     if (sigp < siglimit && signature[sigp] == '.') {
 670                         // support old-style GJC signatures
 671                         // The signature produced was
 672                         // Lfoo/Outer<Lfoo/X;>;.Lfoo/Outer$Inner<Lfoo/Y;>;
 673                         // rather than say
 674                         // Lfoo/Outer<Lfoo/X;>.Inner<Lfoo/Y;>;
 675                         // so we skip past ".Lfoo/Outer$"
 676                         sigp += (sbp - startSbp) + // "foo/Outer"
 677                             3;  // ".L" and "$"
 678                         signatureBuffer[sbp++] = (byte)'$';
 679                         break;
 680                     } else {
 681                         sbp = startSbp;
 682                         return outer;
 683                     }
 684                 case '.':
 685                     signatureBuffer[sbp++] = (byte)'$';
 686                     break;
 687                 default:
 688                     throw new AssertionError(signature[sigp-1]);
 689                 }
 690                 continue;
 691 
 692             case '.':
 693                 //we have seen an enclosing non-generic class
 694                 if (outer != Type.noType) {
 695                     t = enterClass(readName(signatureBuffer,
 696                                                  startSbp,
 697                                                  sbp - startSbp));
 698                     outer = new ClassType(outer, List.nil(), t);
 699                 }
 700                 signatureBuffer[sbp++] = (byte)'$';
 701                 continue;
 702             case '/':
 703                 signatureBuffer[sbp++] = (byte)'.';
 704                 continue;
 705             default:
 706                 signatureBuffer[sbp++] = c;
 707                 continue;
 708             }
 709         }
 710     }
 711 
 712     /** Quote a bogus signature for display inside an error message.
 713      */
 714     String quoteBadSignature() {
 715         String sigString;
 716         try {
 717             sigString = Convert.utf2string(signature, sigp, siglimit - sigp, Convert.Validation.NONE);
 718         } catch (InvalidUtfException e) {
 719             throw new AssertionError(e);
 720         }
 721         if (sigString.length() > 32)
 722             sigString = sigString.substring(0, 32) + "...";
 723         return "\"" + sigString + "\"";
 724     }
 725 
 726     /** Convert (implicit) signature to list of types
 727      *  until `terminator' is encountered.
 728      */
 729     List<Type> sigToTypes(char terminator) {
 730         List<Type> head = List.of(null);
 731         List<Type> tail = head;
 732         while (signature[sigp] != terminator)
 733             tail = tail.setTail(List.of(sigToType()));
 734         sigp++;
 735         return head.tail;
 736     }
 737 
 738     /** Convert signature to type parameters, where signature is a byte
 739      *  array segment.
 740      */
 741     List<Type> sigToTypeParams(byte[] sig, int offset, int len) {
 742         signature = sig;
 743         sigp = offset;
 744         siglimit = offset + len;
 745         return sigToTypeParams();
 746     }
 747 
 748     /** Convert signature to type parameters, where signature is implicit.
 749      */
 750     List<Type> sigToTypeParams() {
 751         List<Type> tvars = List.nil();
 752         if (signature[sigp] == '<') {
 753             sigp++;
 754             int start = sigp;
 755             sigEnterPhase = true;
 756             while (signature[sigp] != '>')
 757                 tvars = tvars.prepend(sigToTypeParam());
 758             sigEnterPhase = false;
 759             sigp = start;
 760             while (signature[sigp] != '>')
 761                 sigToTypeParam();
 762             sigp++;
 763         }
 764         return tvars.reverse();
 765     }
 766 
 767     /** Convert (implicit) signature to type parameter.
 768      */
 769     Type sigToTypeParam() {
 770         int start = sigp;
 771         while (signature[sigp] != ':') sigp++;
 772         Name name = readName(signature, start, sigp - start);
 773         TypeVar tvar;
 774         if (sigEnterPhase) {
 775             tvar = new TypeVar(name, currentOwner, syms.botType);
 776             typevars.enter(tvar.tsym);
 777         } else {
 778             tvar = (TypeVar)findTypeVar(name);
 779         }
 780         List<Type> bounds = List.nil();
 781         boolean allInterfaces = false;
 782         if (signature[sigp] == ':' && signature[sigp+1] == ':') {
 783             sigp++;
 784             allInterfaces = true;
 785         }
 786         while (signature[sigp] == ':') {
 787             sigp++;
 788             bounds = bounds.prepend(sigToType());
 789         }
 790         if (!sigEnterPhase) {
 791             types.setBounds(tvar, bounds.reverse(), allInterfaces);
 792         }
 793         return tvar;
 794     }
 795 
 796     /** Find type variable with given name in `typevars' scope.
 797      */
 798     Type findTypeVar(Name name) {
 799         Symbol s = typevars.findFirst(name);
 800         if (s != null) {
 801             return s.type;
 802         } else {
 803             if (readingClassAttr) {
 804                 // While reading the class attribute, the supertypes
 805                 // might refer to a type variable from an enclosing element
 806                 // (method or class).
 807                 // If the type variable is defined in the enclosing class,
 808                 // we can actually find it in
 809                 // currentOwner.owner.type.getTypeArguments()
 810                 // However, until we have read the enclosing method attribute
 811                 // we don't know for sure if this owner is correct.  It could
 812                 // be a method and there is no way to tell before reading the
 813                 // enclosing method attribute.
 814                 TypeVar t = new TypeVar(name, currentOwner, syms.botType);
 815                 missingTypeVariables = missingTypeVariables.prepend(t);
 816                 // System.err.println("Missing type var " + name);
 817                 return t;
 818             }
 819             throw badClassFile("undecl.type.var", name);
 820         }
 821     }
 822 
 823     private Name readName(byte[] buf, int off, int len) {
 824         try {
 825             return names.fromUtf(buf, off, len, utf8validation);
 826         } catch (InvalidUtfException e) {
 827             if (warnOnIllegalUtf8) {
 828                 log.warning(Warnings.InvalidUtf8InClassfile(currentClassFile,
 829                     Fragments.BadUtf8ByteSequenceAt(sigp)));
 830                 return names.fromUtfLax(buf, off, len);
 831             }
 832             throw badClassFile(Fragments.BadUtf8ByteSequenceAt(sigp));
 833         }
 834     }
 835 
 836 /* **********************************************************************
 837  * Reading Attributes
 838  ***********************************************************************/
 839 
 840     protected enum AttributeKind { CLASS, MEMBER }
 841 
 842     protected abstract class AttributeReader {
 843         protected AttributeReader(Name name, ClassFile.Version version, Set<AttributeKind> kinds) {
 844             this.name = name;
 845             this.version = version;
 846             this.kinds = kinds;
 847         }
 848 
 849         protected boolean accepts(AttributeKind kind) {
 850             if (kinds.contains(kind)) {
 851                 if (majorVersion > version.major || (majorVersion == version.major && minorVersion >= version.minor))
 852                     return true;
 853 
 854                 if (!warnedAttrs.contains(name)) {
 855                     JavaFileObject prev = log.useSource(currentClassFile);
 856                     try {
 857                         lint.logIfEnabled(
 858                                     LintWarnings.FutureAttr(name, version.major, version.minor, majorVersion, minorVersion));
 859                     } finally {
 860                         log.useSource(prev);
 861                     }
 862                     warnedAttrs.add(name);
 863                 }
 864             }
 865             return false;
 866         }
 867 
 868         protected abstract void read(Symbol sym, int attrLen);
 869 
 870         protected final Name name;
 871         protected final ClassFile.Version version;
 872         protected final Set<AttributeKind> kinds;
 873     }
 874 
 875     protected Set<AttributeKind> CLASS_ATTRIBUTE =
 876             EnumSet.of(AttributeKind.CLASS);
 877     protected Set<AttributeKind> MEMBER_ATTRIBUTE =
 878             EnumSet.of(AttributeKind.MEMBER);
 879     protected Set<AttributeKind> CLASS_OR_MEMBER_ATTRIBUTE =
 880             EnumSet.of(AttributeKind.CLASS, AttributeKind.MEMBER);
 881 
 882     protected Map<Name, AttributeReader> attributeReaders = new HashMap<>();
 883 
 884     private void initAttributeReaders() {
 885         AttributeReader[] readers = {
 886             // v45.3 attributes
 887 
 888             new AttributeReader(names.Code, V45_3, MEMBER_ATTRIBUTE) {
 889                 protected void read(Symbol sym, int attrLen) {
 890                     if (saveParameterNames)
 891                         ((MethodSymbol)sym).code = readCode(sym);
 892                     else
 893                         bp = bp + attrLen;
 894                 }
 895             },
 896 
 897             new AttributeReader(names.ConstantValue, V45_3, MEMBER_ATTRIBUTE) {
 898                 protected void read(Symbol sym, int attrLen) {
 899                     Object v = poolReader.getConstant(nextChar());
 900                     // Ignore ConstantValue attribute if field not final.
 901                     if ((sym.flags() & FINAL) == 0) {
 902                         return;
 903                     }
 904                     VarSymbol var = (VarSymbol) sym;
 905                     switch (var.type.getTag()) {
 906                        case BOOLEAN:
 907                        case BYTE:
 908                        case CHAR:
 909                        case SHORT:
 910                        case INT:
 911                            checkType(var, Integer.class, v);
 912                            break;
 913                        case LONG:
 914                            checkType(var, Long.class, v);
 915                            break;
 916                        case FLOAT:
 917                            checkType(var, Float.class, v);
 918                            break;
 919                        case DOUBLE:
 920                            checkType(var, Double.class, v);
 921                            break;
 922                        case CLASS:
 923                            if (var.type.tsym == syms.stringType.tsym) {
 924                                checkType(var, String.class, v);
 925                            } else {
 926                                throw badClassFile("bad.constant.value.type", var.type);
 927                            }
 928                            break;
 929                        default:
 930                            // ignore ConstantValue attribute if type is not primitive or String
 931                            return;
 932                     }
 933                     if (v instanceof Integer intVal && !var.type.getTag().checkRange(intVal)) {
 934                         throw badClassFile("bad.constant.range", v, var, var.type);
 935                     }
 936                     var.setData(v);
 937                 }
 938 
 939                 void checkType(Symbol var, Class<?> clazz, Object value) {
 940                     if (!clazz.isInstance(value)) {
 941                         throw badClassFile("bad.constant.value", value, var, clazz.getSimpleName());
 942                     }
 943                 }
 944             },
 945 
 946             new AttributeReader(names.Deprecated, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 947                 protected void read(Symbol sym, int attrLen) {
 948                     Symbol s = sym.owner.kind == MDL ? sym.owner : sym;
 949 
 950                     s.flags_field |= DEPRECATED;
 951                 }
 952             },
 953 
 954             new AttributeReader(names.Exceptions, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 955                 protected void read(Symbol sym, int attrLen) {
 956                     int nexceptions = nextChar();
 957                     List<Type> thrown = List.nil();
 958                     for (int j = 0; j < nexceptions; j++)
 959                         thrown = thrown.prepend(poolReader.getClass(nextChar()).type);
 960                     if (sym.type.getThrownTypes().isEmpty())
 961                         sym.type.asMethodType().thrown = thrown.reverse();
 962                 }
 963             },
 964 
 965             new AttributeReader(names.InnerClasses, V45_3, CLASS_ATTRIBUTE) {
 966                 protected void read(Symbol sym, int attrLen) {
 967                     ClassSymbol c = (ClassSymbol) sym;
 968                     if (currentModule.module_info == c) {
 969                         //prevent entering the classes too soon:
 970                         skipInnerClasses();
 971                     } else {
 972                         readInnerClasses(c);
 973                     }
 974                 }
 975             },
 976 
 977             new AttributeReader(names.LocalVariableTable, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
 978                 protected void read(Symbol sym, int attrLen) {
 979                     int newbp = bp + attrLen;
 980                     if (saveParameterNames) {
 981                         // Pick up parameter names from the variable table.
 982                         // Parameter names are not explicitly identified as such,
 983                         // but all parameter name entries in the LocalVariableTable
 984                         // have a start_pc of 0.  Therefore, we record the name
 985                         // indices of all slots with a start_pc of zero in the
 986                         // parameterNameIndices array.
 987                         // Note that this implicitly honors the JVMS spec that
 988                         // there may be more than one LocalVariableTable, and that
 989                         // there is no specified ordering for the entries.
 990                         int numEntries = nextChar();
 991                         for (int i = 0; i < numEntries; i++) {
 992                             int start_pc = nextChar();
 993                             int length = nextChar();
 994                             int nameIndex = nextChar();
 995                             int sigIndex = nextChar();
 996                             int register = nextChar();
 997                             if (start_pc == 0) {
 998                                 // ensure array large enough
 999                                 if (register >= parameterNameIndicesLvt.length) {
1000                                     int newSize =
1001                                             Math.max(register + 1, parameterNameIndicesLvt.length + 8);
1002                                     parameterNameIndicesLvt =
1003                                             Arrays.copyOf(parameterNameIndicesLvt, newSize);
1004                                 }
1005                                 parameterNameIndicesLvt[register] = nameIndex;
1006                             }
1007                         }
1008                     }
1009                     bp = newbp;
1010                 }
1011             },
1012 
1013             new AttributeReader(names.SourceFile, V45_3, CLASS_ATTRIBUTE) {
1014                 protected void read(Symbol sym, int attrLen) {
1015                     ClassSymbol c = (ClassSymbol) sym;
1016                     Name n = poolReader.getName(nextChar());
1017                     c.sourcefile = new SourceFileObject(n);
1018                     // If the class is a toplevel class, originating from a Java source file,
1019                     // but the class name does not match the file name, then it is
1020                     // an auxiliary class.
1021                     String sn = n.toString();
1022                     if (c.owner.kind == PCK &&
1023                         sn.endsWith(".java") &&
1024                         !sn.equals(c.name.toString()+".java")) {
1025                         c.flags_field |= AUXILIARY;
1026                     }
1027                 }
1028             },
1029 
1030             new AttributeReader(names.Synthetic, V45_3, CLASS_OR_MEMBER_ATTRIBUTE) {
1031                 protected void read(Symbol sym, int attrLen) {
1032                     sym.flags_field |= SYNTHETIC;
1033                 }
1034             },
1035 
1036             // standard v49 attributes
1037 
1038             new AttributeReader(names.EnclosingMethod, V49, CLASS_ATTRIBUTE) {
1039                 protected void read(Symbol sym, int attrLen) {
1040                     int newbp = bp + attrLen;
1041                     readEnclosingMethodAttr(sym);
1042                     bp = newbp;
1043                 }
1044             },
1045 
1046             new AttributeReader(names.Signature, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1047                 protected void read(Symbol sym, int attrLen) {
1048                     if (sym.kind == TYP) {
1049                         ClassSymbol c = (ClassSymbol) sym;
1050                         readingClassAttr = true;
1051                         try {
1052                             ClassType ct1 = (ClassType)c.type;
1053                             Assert.check(c == currentOwner);
1054                             ct1.typarams_field = poolReader.getName(nextChar())
1055                                     .map(ClassReader.this::sigToTypeParams);
1056                             ct1.supertype_field = sigToType();
1057                             ListBuffer<Type> is = new ListBuffer<>();
1058                             while (sigp != siglimit) is.append(sigToType());
1059                             ct1.interfaces_field = is.toList();
1060                         } finally {
1061                             readingClassAttr = false;
1062                         }
1063                     } else {
1064                         List<Type> thrown = sym.type.getThrownTypes();
1065                         sym.type = poolReader.getType(nextChar());
1066                         //- System.err.println(" # " + sym.type);
1067                         if (sym.kind == MTH && sym.type.getThrownTypes().isEmpty())
1068                             sym.type.asMethodType().thrown = thrown;
1069 
1070                     }
1071                 }
1072             },
1073 
1074             // v49 annotation attributes
1075 
1076             new AttributeReader(names.AnnotationDefault, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1077                 protected void read(Symbol sym, int attrLen) {
1078                     attachAnnotationDefault(sym);
1079                 }
1080             },
1081 
1082             new AttributeReader(names.RuntimeInvisibleAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1083                 protected void read(Symbol sym, int attrLen) {
1084                     attachAnnotations(sym);
1085                 }
1086             },
1087 
1088             new AttributeReader(names.RuntimeInvisibleParameterAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1089                 protected void read(Symbol sym, int attrLen) {
1090                     readParameterAnnotations(sym);
1091                 }
1092             },
1093 
1094             new AttributeReader(names.RuntimeVisibleAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1095                 protected void read(Symbol sym, int attrLen) {
1096                     attachAnnotations(sym);
1097                 }
1098             },
1099 
1100             new AttributeReader(names.RuntimeVisibleParameterAnnotations, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1101                 protected void read(Symbol sym, int attrLen) {
1102                     readParameterAnnotations(sym);
1103                 }
1104             },
1105 
1106             // additional "legacy" v49 attributes, superseded by flags
1107 
1108             new AttributeReader(names.Annotation, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1109                 protected void read(Symbol sym, int attrLen) {
1110                     sym.flags_field |= ANNOTATION;
1111                 }
1112             },
1113 
1114             new AttributeReader(names.Bridge, V49, MEMBER_ATTRIBUTE) {
1115                 protected void read(Symbol sym, int attrLen) {
1116                     sym.flags_field |= BRIDGE;
1117                 }
1118             },
1119 
1120             new AttributeReader(names.Enum, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1121                 protected void read(Symbol sym, int attrLen) {
1122                     sym.flags_field |= ENUM;
1123                 }
1124             },
1125 
1126             new AttributeReader(names.Varargs, V49, CLASS_OR_MEMBER_ATTRIBUTE) {
1127                 protected void read(Symbol sym, int attrLen) {
1128                     sym.flags_field |= VARARGS;
1129                 }
1130             },
1131 
1132             new AttributeReader(names.RuntimeVisibleTypeAnnotations, V52, CLASS_OR_MEMBER_ATTRIBUTE) {
1133                 protected void read(Symbol sym, int attrLen) {
1134                     attachTypeAnnotations(sym);
1135                 }
1136             },
1137 
1138             new AttributeReader(names.RuntimeInvisibleTypeAnnotations, V52, CLASS_OR_MEMBER_ATTRIBUTE) {
1139                 protected void read(Symbol sym, int attrLen) {
1140                     attachTypeAnnotations(sym);
1141                 }
1142             },
1143 
1144             // The following attributes for a Code attribute are not currently handled
1145             // StackMapTable
1146             // SourceDebugExtension
1147             // LineNumberTable
1148             // LocalVariableTypeTable
1149 
1150             // standard v52 attributes
1151 
1152             new AttributeReader(names.MethodParameters, V52, MEMBER_ATTRIBUTE) {
1153                 protected void read(Symbol sym, int attrlen) {
1154                     int newbp = bp + attrlen;
1155                     if (saveParameterNames) {
1156                         int numEntries = nextByte();
1157                         allParameterAccessFlags = new int[numEntries];
1158                         parameterNameIndicesMp = new int[numEntries];
1159                         parameterAccessFlags = new int[numEntries];
1160                         int allParamIndex = 0;
1161                         int index = 0;
1162                         for (int i = 0; i < numEntries; i++) {
1163                             int nameIndex = nextChar();
1164                             int flags = nextChar();
1165                             allParameterAccessFlags[allParamIndex++] = flags;
1166                             if ((flags & (Flags.MANDATED | Flags.SYNTHETIC)) != 0) {
1167                                 continue;
1168                             }
1169                             parameterNameIndicesMp[index] = nameIndex;
1170                             parameterAccessFlags[index] = flags;
1171                             index++;
1172                         }
1173                     }
1174                     bp = newbp;
1175                 }
1176             },
1177 
1178             // standard v53 attributes
1179 
1180             new AttributeReader(names.Module, V53, CLASS_ATTRIBUTE) {
1181                 @Override
1182                 protected boolean accepts(AttributeKind kind) {
1183                     return super.accepts(kind) && allowModules;
1184                 }
1185                 protected void read(Symbol sym, int attrLen) {
1186                     if (sym.kind == TYP && sym.owner.kind == MDL) {
1187                         ModuleSymbol msym = (ModuleSymbol) sym.owner;
1188                         ListBuffer<Directive> directives = new ListBuffer<>();
1189 
1190                         Name moduleName = poolReader.peekModuleName(nextChar(), ClassReader.this::readName);
1191                         if (currentModule.name != moduleName) {
1192                             throw badClassFile("module.name.mismatch", moduleName, currentModule.name);
1193                         }
1194 
1195                         Set<ModuleFlags> moduleFlags = readModuleFlags(nextChar());
1196                         msym.flags.addAll(moduleFlags);
1197                         msym.version = optPoolEntry(nextChar(), poolReader::getName, null);
1198 
1199                         ListBuffer<RequiresDirective> requires = new ListBuffer<>();
1200                         int nrequires = nextChar();
1201                         for (int i = 0; i < nrequires; i++) {
1202                             ModuleSymbol rsym = poolReader.getModule(nextChar());
1203                             Set<RequiresFlag> flags = readRequiresFlags(nextChar());
1204                             if (rsym == syms.java_base && majorVersion >= V54.major) {
1205                                 if (flags.contains(RequiresFlag.TRANSITIVE) &&
1206                                     (majorVersion != Version.MAX().major || !previewClassFile) &&
1207                                     !preview.participatesInPreview(syms, msym)) {
1208                                     throw badClassFile("bad.requires.flag", RequiresFlag.TRANSITIVE);
1209                                 }
1210                                 if (flags.contains(RequiresFlag.STATIC_PHASE)) {
1211                                     throw badClassFile("bad.requires.flag", RequiresFlag.STATIC_PHASE);
1212                                 }
1213                             }
1214                             nextChar(); // skip compiled version
1215                             requires.add(new RequiresDirective(rsym, flags));
1216                         }
1217                         msym.requires = requires.toList();
1218                         directives.addAll(msym.requires);
1219 
1220                         ListBuffer<ExportsDirective> exports = new ListBuffer<>();
1221                         int nexports = nextChar();
1222                         for (int i = 0; i < nexports; i++) {
1223                             PackageSymbol p = poolReader.getPackage(nextChar());
1224                             Set<ExportsFlag> flags = readExportsFlags(nextChar());
1225                             int nto = nextChar();
1226                             List<ModuleSymbol> to;
1227                             if (nto == 0) {
1228                                 to = null;
1229                             } else {
1230                                 ListBuffer<ModuleSymbol> lb = new ListBuffer<>();
1231                                 for (int t = 0; t < nto; t++)
1232                                     lb.append(poolReader.getModule(nextChar()));
1233                                 to = lb.toList();
1234                             }
1235                             exports.add(new ExportsDirective(p, to, flags));
1236                         }
1237                         msym.exports = exports.toList();
1238                         directives.addAll(msym.exports);
1239                         ListBuffer<OpensDirective> opens = new ListBuffer<>();
1240                         int nopens = nextChar();
1241                         if (nopens != 0 && msym.flags.contains(ModuleFlags.OPEN)) {
1242                             throw badClassFile("module.non.zero.opens", currentModule.name);
1243                         }
1244                         for (int i = 0; i < nopens; i++) {
1245                             PackageSymbol p = poolReader.getPackage(nextChar());
1246                             Set<OpensFlag> flags = readOpensFlags(nextChar());
1247                             int nto = nextChar();
1248                             List<ModuleSymbol> to;
1249                             if (nto == 0) {
1250                                 to = null;
1251                             } else {
1252                                 ListBuffer<ModuleSymbol> lb = new ListBuffer<>();
1253                                 for (int t = 0; t < nto; t++)
1254                                     lb.append(poolReader.getModule(nextChar()));
1255                                 to = lb.toList();
1256                             }
1257                             opens.add(new OpensDirective(p, to, flags));
1258                         }
1259                         msym.opens = opens.toList();
1260                         directives.addAll(msym.opens);
1261 
1262                         msym.directives = directives.toList();
1263 
1264                         ListBuffer<InterimUsesDirective> uses = new ListBuffer<>();
1265                         int nuses = nextChar();
1266                         for (int i = 0; i < nuses; i++) {
1267                             Name srvc = poolReader.peekClassName(nextChar(), this::classNameMapper);
1268                             uses.add(new InterimUsesDirective(srvc));
1269                         }
1270                         interimUses = uses.toList();
1271 
1272                         ListBuffer<InterimProvidesDirective> provides = new ListBuffer<>();
1273                         int nprovides = nextChar();
1274                         for (int p = 0; p < nprovides; p++) {
1275                             Name srvc = poolReader.peekClassName(nextChar(), this::classNameMapper);
1276                             int nimpls = nextChar();
1277                             ListBuffer<Name> impls = new ListBuffer<>();
1278                             for (int i = 0; i < nimpls; i++) {
1279                                 impls.append(poolReader.peekClassName(nextChar(), this::classNameMapper));
1280                             provides.add(new InterimProvidesDirective(srvc, impls.toList()));
1281                             }
1282                         }
1283                         interimProvides = provides.toList();
1284                     }
1285                 }
1286 
1287                 private Name classNameMapper(byte[] arr, int offset, int length) throws InvalidUtfException {
1288                     byte[] buf = ClassFile.internalize(arr, offset, length);
1289                     try {
1290                         return names.fromUtf(buf, 0, buf.length, utf8validation);
1291                     } catch (InvalidUtfException e) {
1292                         if (warnOnIllegalUtf8) {
1293                             log.warning(Warnings.InvalidUtf8InClassfile(currentClassFile,
1294                                 Fragments.BadUtf8ByteSequenceAt(e.getOffset())));
1295                             return names.fromUtfLax(buf, 0, buf.length);
1296                         }
1297                         throw e;
1298                     }
1299                 }
1300             },
1301 
1302             new AttributeReader(names.ModuleResolution, V53, CLASS_ATTRIBUTE) {
1303                 @Override
1304                 protected boolean accepts(AttributeKind kind) {
1305                     return super.accepts(kind) && allowModules;
1306                 }
1307                 protected void read(Symbol sym, int attrLen) {
1308                     if (sym.kind == TYP && sym.owner.kind == MDL) {
1309                         ModuleSymbol msym = (ModuleSymbol) sym.owner;
1310                         msym.resolutionFlags.addAll(readModuleResolutionFlags(nextChar()));
1311                     }
1312                 }
1313             },
1314 
1315             new AttributeReader(names.Record, V58, CLASS_ATTRIBUTE) {
1316                 @Override
1317                 protected boolean accepts(AttributeKind kind) {
1318                     return super.accepts(kind) && allowRecords;
1319                 }
1320                 protected void read(Symbol sym, int attrLen) {
1321                     if (sym.kind == TYP) {
1322                         sym.flags_field |= RECORD;
1323                     }
1324                     int componentCount = nextChar();
1325                     ListBuffer<RecordComponent> components = new ListBuffer<>();
1326                     for (int i = 0; i < componentCount; i++) {
1327                         Name name = poolReader.getName(nextChar());
1328                         Type type = poolReader.getType(nextChar());
1329                         RecordComponent c = new RecordComponent(name, type, sym);
1330                         readAttrs(c, AttributeKind.MEMBER);
1331                         components.add(c);
1332                     }
1333                     ((ClassSymbol) sym).setRecordComponents(components.toList());
1334                 }
1335             },
1336             new AttributeReader(names.PermittedSubclasses, V59, CLASS_ATTRIBUTE) {
1337                 @Override
1338                 protected boolean accepts(AttributeKind kind) {
1339                     return super.accepts(kind) && allowSealedTypes;
1340                 }
1341                 protected void read(Symbol sym, int attrLen) {
1342                     if (sym.kind == TYP) {
1343                         ListBuffer<Symbol> subtypes = new ListBuffer<>();
1344                         int numberOfPermittedSubtypes = nextChar();
1345                         for (int i = 0; i < numberOfPermittedSubtypes; i++) {
1346                             subtypes.add(poolReader.getClass(nextChar()));
1347                         }
1348                         ((ClassSymbol)sym).setPermittedSubclasses(subtypes.toList());
1349                     }
1350                 }
1351             },
1352         };
1353 
1354         for (AttributeReader r: readers)
1355             attributeReaders.put(r.name, r);
1356     }
1357 
1358     protected void readEnclosingMethodAttr(Symbol sym) {
1359         // sym is a nested class with an "Enclosing Method" attribute
1360         // remove sym from it's current owners scope and place it in
1361         // the scope specified by the attribute
1362         sym.owner.members().remove(sym);
1363         ClassSymbol self = (ClassSymbol)sym;
1364         ClassSymbol c = poolReader.getClass(nextChar());
1365         NameAndType nt = optPoolEntry(nextChar(), poolReader::getNameAndType, null);
1366 
1367         if (c.members_field == null || c.kind != TYP)
1368             throw badClassFile("bad.enclosing.class", self, c);
1369 
1370         MethodSymbol m = findMethod(nt, c.members_field, self.flags());
1371         if (nt != null && m == null)
1372             throw badEnclosingMethod(self);
1373 
1374         self.name = simpleBinaryName(self.flatname, c.flatname) ;
1375         self.owner = m != null ? m : c;
1376         if (self.name.isEmpty())
1377             self.fullname = names.empty;
1378         else
1379             self.fullname = ClassSymbol.formFullName(self.name, self.owner);
1380 
1381         if (m != null) {
1382             ((ClassType)sym.type).setEnclosingType(m.type);
1383         } else if ((self.flags_field & STATIC) == 0) {
1384             ((ClassType)sym.type).setEnclosingType(c.type);
1385         } else {
1386             ((ClassType)sym.type).setEnclosingType(Type.noType);
1387         }
1388         enterTypevars(self, self.type);
1389         if (!missingTypeVariables.isEmpty()) {
1390             ListBuffer<Type> typeVars =  new ListBuffer<>();
1391             for (Type typevar : missingTypeVariables) {
1392                 typeVars.append(findTypeVar(typevar.tsym.name));
1393             }
1394             foundTypeVariables = typeVars.toList();
1395         } else {
1396             foundTypeVariables = List.nil();
1397         }
1398     }
1399 
1400     // See java.lang.Class
1401     private Name simpleBinaryName(Name self, Name enclosing) {
1402         if (!self.startsWith(enclosing)) {
1403             throw badClassFile("bad.enclosing.method", self);
1404         }
1405 
1406         String simpleBinaryName = self.toString().substring(enclosing.toString().length());
1407         if (simpleBinaryName.length() < 1 || simpleBinaryName.charAt(0) != '$')
1408             throw badClassFile("bad.enclosing.method", self);
1409         int index = 1;
1410         while (index < simpleBinaryName.length() &&
1411                isAsciiDigit(simpleBinaryName.charAt(index)))
1412             index++;
1413         return names.fromString(simpleBinaryName.substring(index));
1414     }
1415 
1416     private MethodSymbol findMethod(NameAndType nt, Scope scope, long flags) {
1417         if (nt == null)
1418             return null;
1419 
1420         MethodType type = nt.type.asMethodType();
1421 
1422         for (Symbol sym : scope.getSymbolsByName(nt.name)) {
1423             if (sym.kind == MTH && isSameBinaryType(sym.type.asMethodType(), type))
1424                 return (MethodSymbol)sym;
1425         }
1426 
1427         if (nt.name != names.init)
1428             // not a constructor
1429             return null;
1430         if ((flags & INTERFACE) != 0)
1431             // no enclosing instance
1432             return null;
1433         if (nt.type.getParameterTypes().isEmpty())
1434             // no parameters
1435             return null;
1436 
1437         // A constructor of an inner class.
1438         // Remove the first argument (the enclosing instance)
1439         nt = new NameAndType(nt.name, new MethodType(nt.type.getParameterTypes().tail,
1440                                  nt.type.getReturnType(),
1441                                  nt.type.getThrownTypes(),
1442                                  syms.methodClass));
1443         // Try searching again
1444         return findMethod(nt, scope, flags);
1445     }
1446 
1447     /** Similar to Types.isSameType but avoids completion */
1448     private boolean isSameBinaryType(MethodType mt1, MethodType mt2) {
1449         List<Type> types1 = types.erasure(mt1.getParameterTypes())
1450             .prepend(types.erasure(mt1.getReturnType()));
1451         List<Type> types2 = mt2.getParameterTypes().prepend(mt2.getReturnType());
1452         while (!types1.isEmpty() && !types2.isEmpty()) {
1453             if (types1.head.tsym != types2.head.tsym)
1454                 return false;
1455             types1 = types1.tail;
1456             types2 = types2.tail;
1457         }
1458         return types1.isEmpty() && types2.isEmpty();
1459     }
1460 
1461     /**
1462      * Character.isDigit answers <tt>true</tt> to some non-ascii
1463      * digits.  This one does not.  <b>copied from java.lang.Class</b>
1464      */
1465     private static boolean isAsciiDigit(char c) {
1466         return '0' <= c && c <= '9';
1467     }
1468 
1469     /** Read member attributes.
1470      */
1471     void readMemberAttrs(Symbol sym) {
1472         readAttrs(sym, AttributeKind.MEMBER);
1473     }
1474 
1475     void readAttrs(Symbol sym, AttributeKind kind) {
1476         char ac = nextChar();
1477         for (int i = 0; i < ac; i++) {
1478             Name attrName = poolReader.getName(nextChar());
1479             int attrLen = nextInt();
1480             AttributeReader r = attributeReaders.get(attrName);
1481             if (r != null && r.accepts(kind))
1482                 r.read(sym, attrLen);
1483             else  {
1484                 bp = bp + attrLen;
1485             }
1486         }
1487     }
1488 
1489     private boolean readingClassAttr = false;
1490     private List<Type> missingTypeVariables = List.nil();
1491     private List<Type> foundTypeVariables = List.nil();
1492 
1493     /** Read class attributes.
1494      */
1495     void readClassAttrs(ClassSymbol c) {
1496         readAttrs(c, AttributeKind.CLASS);
1497     }
1498 
1499     /** Read code block.
1500      */
1501     Code readCode(Symbol owner) {
1502         nextChar(); // max_stack
1503         nextChar(); // max_locals
1504         final int  code_length = nextInt();
1505         bp += code_length;
1506         final char exception_table_length = nextChar();
1507         bp += exception_table_length * 8;
1508         readMemberAttrs(owner);
1509         return null;
1510     }
1511 
1512 /* **********************************************************************
1513  * Reading Java-language annotations
1514  ***********************************************************************/
1515 
1516     /**
1517      * Save annotations.
1518      */
1519     List<CompoundAnnotationProxy> readAnnotations() {
1520         int numAttributes = nextChar();
1521         ListBuffer<CompoundAnnotationProxy> annotations = new ListBuffer<>();
1522         for (int i = 0; i < numAttributes; i++) {
1523             annotations.append(readCompoundAnnotation());
1524         }
1525         return annotations.toList();
1526     }
1527 
1528     /** Attach annotations.
1529      */
1530     void attachAnnotations(final Symbol sym) {
1531         attachAnnotations(sym, readAnnotations());
1532     }
1533 
1534     /**
1535      * Attach annotations.
1536      */
1537     void attachAnnotations(final Symbol sym, List<CompoundAnnotationProxy> annotations) {
1538         if (annotations.isEmpty()) {
1539             return;
1540         }
1541         ListBuffer<CompoundAnnotationProxy> proxies = new ListBuffer<>();
1542         for (CompoundAnnotationProxy proxy : annotations) {
1543             if (proxy.type.tsym.flatName() == syms.proprietaryType.tsym.flatName())
1544                 sym.flags_field |= PROPRIETARY;
1545             else if (proxy.type.tsym.flatName() == syms.profileType.tsym.flatName()) {
1546                 if (profile != Profile.DEFAULT) {
1547                     for (Pair<Name, Attribute> v : proxy.values) {
1548                         if (v.fst == names.value && v.snd instanceof Attribute.Constant constant) {
1549                             if (constant.type == syms.intType && ((Integer) constant.value) > profile.value) {
1550                                 sym.flags_field |= NOT_IN_PROFILE;
1551                             }
1552                         }
1553                     }
1554                 }
1555             } else if (proxy.type.tsym.flatName() == syms.previewFeatureInternalType.tsym.flatName()) {
1556                 sym.flags_field |= PREVIEW_API;
1557                 setFlagIfAttributeTrue(proxy, sym, names.reflective, PREVIEW_REFLECTIVE);
1558             } else if (proxy.type.tsym.flatName() == syms.valueBasedInternalType.tsym.flatName()) {
1559                 Assert.check(sym.kind == TYP);
1560                 sym.flags_field |= VALUE_BASED;
1561             } else if (proxy.type.tsym.flatName() == syms.restrictedInternalType.tsym.flatName()) {
1562                 Assert.check(sym.kind == MTH);
1563                 sym.flags_field |= RESTRICTED;
1564             } else {
1565                 if (proxy.type.tsym == syms.annotationTargetType.tsym) {
1566                     target = proxy;
1567                 } else if (proxy.type.tsym == syms.repeatableType.tsym) {
1568                     repeatable = proxy;
1569                 } else if (proxy.type.tsym == syms.deprecatedType.tsym) {
1570                     sym.flags_field |= (DEPRECATED | DEPRECATED_ANNOTATION);
1571                     setFlagIfAttributeTrue(proxy, sym, names.forRemoval, DEPRECATED_REMOVAL);
1572                 }  else if (proxy.type.tsym == syms.previewFeatureType.tsym) {
1573                     sym.flags_field |= PREVIEW_API;
1574                     setFlagIfAttributeTrue(proxy, sym, names.reflective, PREVIEW_REFLECTIVE);
1575                 }  else if (proxy.type.tsym == syms.valueBasedType.tsym && sym.kind == TYP) {
1576                     sym.flags_field |= VALUE_BASED;
1577                 }  else if (proxy.type.tsym == syms.restrictedType.tsym) {
1578                     Assert.check(sym.kind == MTH);
1579                     sym.flags_field |= RESTRICTED;
1580                 }
1581                 proxies.append(proxy);
1582             }
1583         }
1584         annotate.normal(new AnnotationCompleter(sym, proxies.toList()));
1585     }
1586     //where:
1587         private void setFlagIfAttributeTrue(CompoundAnnotationProxy proxy, Symbol sym, Name attribute, long flag) {
1588             for (Pair<Name, Attribute> v : proxy.values) {
1589                 if (v.fst == attribute && v.snd instanceof Attribute.Constant constant) {
1590                     if (constant.type == syms.booleanType && ((Integer) constant.value) != 0) {
1591                         sym.flags_field |= flag;
1592                     }
1593                 }
1594             }
1595         }
1596 
1597     /** Read parameter annotations.
1598      */
1599     void readParameterAnnotations(Symbol meth) {
1600         int numParameters;
1601         try {
1602             numParameters = buf.getByte(bp++) & 0xFF;
1603         } catch (UnderflowException e) {
1604             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
1605         }
1606         if (parameterAnnotations == null) {
1607             parameterAnnotations = new ParameterAnnotations[numParameters];
1608         } else if (parameterAnnotations.length != numParameters) {
1609             //the RuntimeVisibleParameterAnnotations and RuntimeInvisibleParameterAnnotations
1610             //provide annotations for a different number of parameters, ignore:
1611             lint.logIfEnabled(LintWarnings.RuntimeVisibleInvisibleParamAnnotationsMismatch(currentClassFile));
1612             for (int pnum = 0; pnum < numParameters; pnum++) {
1613                 readAnnotations();
1614             }
1615             parameterAnnotations = null;
1616             return ;
1617         }
1618         for (int pnum = 0; pnum < numParameters; pnum++) {
1619             if (parameterAnnotations[pnum] == null) {
1620                 parameterAnnotations[pnum] = new ParameterAnnotations();
1621             }
1622             parameterAnnotations[pnum].add(readAnnotations());
1623         }
1624     }
1625 
1626     void attachTypeAnnotations(final Symbol sym) {
1627         int numAttributes = nextChar();
1628         if (numAttributes != 0) {
1629             ListBuffer<TypeAnnotationProxy> proxies = new ListBuffer<>();
1630             for (int i = 0; i < numAttributes; i++)
1631                 proxies.append(readTypeAnnotation());
1632             annotate.normal(new TypeAnnotationCompleter(sym, proxies.toList()));
1633         }
1634     }
1635 
1636     /** Attach the default value for an annotation element.
1637      */
1638     void attachAnnotationDefault(final Symbol sym) {
1639         final MethodSymbol meth = (MethodSymbol)sym; // only on methods
1640         final Attribute value = readAttributeValue();
1641 
1642         // The default value is set later during annotation. It might
1643         // be the case that the Symbol sym is annotated _after_ the
1644         // repeating instances that depend on this default value,
1645         // because of this we set an interim value that tells us this
1646         // element (most likely) has a default.
1647         //
1648         // Set interim value for now, reset just before we do this
1649         // properly at annotate time.
1650         meth.defaultValue = value;
1651         annotate.normal(new AnnotationDefaultCompleter(meth, value));
1652     }
1653 
1654     Type readTypeOrClassSymbol(int i) {
1655         return readTypeToProxy(i);
1656     }
1657     Type readTypeToProxy(int i) {
1658         if (currentModule.module_info == currentOwner) {
1659             return new ProxyType(i);
1660         } else {
1661             return poolReader.getType(i);
1662         }
1663     }
1664 
1665     CompoundAnnotationProxy readCompoundAnnotation() {
1666         Type t;
1667         if (currentModule.module_info == currentOwner) {
1668             int cpIndex = nextChar();
1669             t = new ProxyType(cpIndex);
1670         } else {
1671             t = readTypeOrClassSymbol(nextChar());
1672         }
1673         int numFields = nextChar();
1674         ListBuffer<Pair<Name,Attribute>> pairs = new ListBuffer<>();
1675         for (int i=0; i<numFields; i++) {
1676             Name name = poolReader.getName(nextChar());
1677             Attribute value = readAttributeValue();
1678             pairs.append(new Pair<>(name, value));
1679         }
1680         return new CompoundAnnotationProxy(t, pairs.toList());
1681     }
1682 
1683     TypeAnnotationProxy readTypeAnnotation() {
1684         TypeAnnotationPosition position = readPosition();
1685         CompoundAnnotationProxy proxy = readCompoundAnnotation();
1686 
1687         return new TypeAnnotationProxy(proxy, position);
1688     }
1689 
1690     TypeAnnotationPosition readPosition() {
1691         int tag = nextByte(); // TargetType tag is a byte
1692 
1693         if (!TargetType.isValidTargetTypeValue(tag))
1694             throw badClassFile("bad.type.annotation.value", String.format("0x%02X", tag));
1695 
1696         TargetType type = TargetType.fromTargetTypeValue(tag);
1697 
1698         switch (type) {
1699         // instanceof
1700         case INSTANCEOF: {
1701             final int offset = nextChar();
1702             final TypeAnnotationPosition position =
1703                 TypeAnnotationPosition.instanceOf(readTypePath());
1704             position.offset = offset;
1705             return position;
1706         }
1707         // new expression
1708         case NEW: {
1709             final int offset = nextChar();
1710             final TypeAnnotationPosition position =
1711                 TypeAnnotationPosition.newObj(readTypePath());
1712             position.offset = offset;
1713             return position;
1714         }
1715         // constructor/method reference receiver
1716         case CONSTRUCTOR_REFERENCE: {
1717             final int offset = nextChar();
1718             final TypeAnnotationPosition position =
1719                 TypeAnnotationPosition.constructorRef(readTypePath());
1720             position.offset = offset;
1721             return position;
1722         }
1723         case METHOD_REFERENCE: {
1724             final int offset = nextChar();
1725             final TypeAnnotationPosition position =
1726                 TypeAnnotationPosition.methodRef(readTypePath());
1727             position.offset = offset;
1728             return position;
1729         }
1730         // local variable
1731         case LOCAL_VARIABLE: {
1732             final int table_length = nextChar();
1733             final int[] newLvarOffset = new int[table_length];
1734             final int[] newLvarLength = new int[table_length];
1735             final int[] newLvarIndex = new int[table_length];
1736 
1737             for (int i = 0; i < table_length; ++i) {
1738                 newLvarOffset[i] = nextChar();
1739                 newLvarLength[i] = nextChar();
1740                 newLvarIndex[i] = nextChar();
1741             }
1742 
1743             final TypeAnnotationPosition position =
1744                     TypeAnnotationPosition.localVariable(readTypePath());
1745             position.lvarOffset = newLvarOffset;
1746             position.lvarLength = newLvarLength;
1747             position.lvarIndex = newLvarIndex;
1748             return position;
1749         }
1750         // resource variable
1751         case RESOURCE_VARIABLE: {
1752             final int table_length = nextChar();
1753             final int[] newLvarOffset = new int[table_length];
1754             final int[] newLvarLength = new int[table_length];
1755             final int[] newLvarIndex = new int[table_length];
1756 
1757             for (int i = 0; i < table_length; ++i) {
1758                 newLvarOffset[i] = nextChar();
1759                 newLvarLength[i] = nextChar();
1760                 newLvarIndex[i] = nextChar();
1761             }
1762 
1763             final TypeAnnotationPosition position =
1764                     TypeAnnotationPosition.resourceVariable(readTypePath());
1765             position.lvarOffset = newLvarOffset;
1766             position.lvarLength = newLvarLength;
1767             position.lvarIndex = newLvarIndex;
1768             return position;
1769         }
1770         // exception parameter
1771         case EXCEPTION_PARAMETER: {
1772             final int exception_index = nextChar();
1773             final TypeAnnotationPosition position =
1774                 TypeAnnotationPosition.exceptionParameter(readTypePath());
1775             position.setExceptionIndex(exception_index);
1776             return position;
1777         }
1778         // method receiver
1779         case METHOD_RECEIVER:
1780             return TypeAnnotationPosition.methodReceiver(readTypePath());
1781         // type parameter
1782         case CLASS_TYPE_PARAMETER: {
1783             final int parameter_index = nextByte();
1784             return TypeAnnotationPosition
1785                 .typeParameter(readTypePath(), parameter_index);
1786         }
1787         case METHOD_TYPE_PARAMETER: {
1788             final int parameter_index = nextByte();
1789             return TypeAnnotationPosition
1790                 .methodTypeParameter(readTypePath(), parameter_index);
1791         }
1792         // type parameter bound
1793         case CLASS_TYPE_PARAMETER_BOUND: {
1794             final int parameter_index = nextByte();
1795             final int bound_index = nextByte();
1796             return TypeAnnotationPosition
1797                 .typeParameterBound(readTypePath(), parameter_index,
1798                                     bound_index);
1799         }
1800         case METHOD_TYPE_PARAMETER_BOUND: {
1801             final int parameter_index = nextByte();
1802             final int bound_index = nextByte();
1803             return TypeAnnotationPosition
1804                 .methodTypeParameterBound(readTypePath(), parameter_index,
1805                                           bound_index);
1806         }
1807         // class extends or implements clause
1808         case CLASS_EXTENDS: {
1809             final int type_index = nextChar();
1810             return TypeAnnotationPosition.classExtends(readTypePath(),
1811                                                        type_index);
1812         }
1813         // throws
1814         case THROWS: {
1815             final int type_index = nextChar();
1816             return TypeAnnotationPosition.methodThrows(readTypePath(),
1817                                                        type_index);
1818         }
1819         // method parameter
1820         case METHOD_FORMAL_PARAMETER: {
1821             final int parameter_index = nextByte();
1822             return TypeAnnotationPosition.methodParameter(readTypePath(),
1823                                                           parameter_index);
1824         }
1825         // type cast
1826         case CAST: {
1827             final int offset = nextChar();
1828             final int type_index = nextByte();
1829             final TypeAnnotationPosition position =
1830                 TypeAnnotationPosition.typeCast(readTypePath(), type_index);
1831             position.offset = offset;
1832             return position;
1833         }
1834         // method/constructor/reference type argument
1835         case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT: {
1836             final int offset = nextChar();
1837             final int type_index = nextByte();
1838             final TypeAnnotationPosition position = TypeAnnotationPosition
1839                 .constructorInvocationTypeArg(readTypePath(), type_index);
1840             position.offset = offset;
1841             return position;
1842         }
1843         case METHOD_INVOCATION_TYPE_ARGUMENT: {
1844             final int offset = nextChar();
1845             final int type_index = nextByte();
1846             final TypeAnnotationPosition position = TypeAnnotationPosition
1847                 .methodInvocationTypeArg(readTypePath(), type_index);
1848             position.offset = offset;
1849             return position;
1850         }
1851         case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT: {
1852             final int offset = nextChar();
1853             final int type_index = nextByte();
1854             final TypeAnnotationPosition position = TypeAnnotationPosition
1855                 .constructorRefTypeArg(readTypePath(), type_index);
1856             position.offset = offset;
1857             return position;
1858         }
1859         case METHOD_REFERENCE_TYPE_ARGUMENT: {
1860             final int offset = nextChar();
1861             final int type_index = nextByte();
1862             final TypeAnnotationPosition position = TypeAnnotationPosition
1863                 .methodRefTypeArg(readTypePath(), type_index);
1864             position.offset = offset;
1865             return position;
1866         }
1867         // We don't need to worry about these
1868         case METHOD_RETURN:
1869             return TypeAnnotationPosition.methodReturn(readTypePath());
1870         case FIELD:
1871             return TypeAnnotationPosition.field(readTypePath());
1872         case UNKNOWN:
1873             throw new AssertionError("jvm.ClassReader: UNKNOWN target type should never occur!");
1874         default:
1875             throw new AssertionError("jvm.ClassReader: Unknown target type for position: " + type);
1876         }
1877     }
1878 
1879     List<TypeAnnotationPosition.TypePathEntry> readTypePath() {
1880         int len = nextByte();
1881         ListBuffer<Integer> loc = new ListBuffer<>();
1882         for (int i = 0; i < len * TypeAnnotationPosition.TypePathEntry.bytesPerEntry; ++i)
1883             loc = loc.append(nextByte());
1884 
1885         return TypeAnnotationPosition.getTypePathFromBinary(loc.toList());
1886 
1887     }
1888 
1889     /**
1890      * Helper function to read an optional pool entry (with given function); this is used while parsing
1891      * InnerClasses and EnclosingMethod attributes, as well as when parsing supertype descriptor,
1892      * as per JVMS.
1893      */
1894     <Z> Z optPoolEntry(int index, IntFunction<Z> poolFunc, Z defaultValue) {
1895         return (index == 0) ?
1896                 defaultValue :
1897                 poolFunc.apply(index);
1898     }
1899 
1900     Attribute readAttributeValue() {
1901         char c;
1902         try {
1903             c = (char)buf.getByte(bp++);
1904         } catch (UnderflowException e) {
1905             throw badClassFile(Fragments.BadClassTruncatedAtOffset(e.getLength()));
1906         }
1907         switch (c) {
1908         case 'B':
1909             return new Attribute.Constant(syms.byteType, poolReader.getConstant(nextChar()));
1910         case 'C':
1911             return new Attribute.Constant(syms.charType, poolReader.getConstant(nextChar()));
1912         case 'D':
1913             return new Attribute.Constant(syms.doubleType, poolReader.getConstant(nextChar()));
1914         case 'F':
1915             return new Attribute.Constant(syms.floatType, poolReader.getConstant(nextChar()));
1916         case 'I':
1917             return new Attribute.Constant(syms.intType, poolReader.getConstant(nextChar()));
1918         case 'J':
1919             return new Attribute.Constant(syms.longType, poolReader.getConstant(nextChar()));
1920         case 'S':
1921             return new Attribute.Constant(syms.shortType, poolReader.getConstant(nextChar()));
1922         case 'Z':
1923             return new Attribute.Constant(syms.booleanType, poolReader.getConstant(nextChar()));
1924         case 's':
1925             return new Attribute.Constant(syms.stringType, poolReader.getName(nextChar()).toString());
1926         case 'e':
1927             return new EnumAttributeProxy(readTypeToProxy(nextChar()), poolReader.getName(nextChar()));
1928         case 'c':
1929             return new ClassAttributeProxy(readTypeOrClassSymbol(nextChar()));
1930         case '[': {
1931             int n = nextChar();
1932             ListBuffer<Attribute> l = new ListBuffer<>();
1933             for (int i=0; i<n; i++)
1934                 l.append(readAttributeValue());
1935             return new ArrayAttributeProxy(l.toList());
1936         }
1937         case '@':
1938             return readCompoundAnnotation();
1939         default:
1940             throw new AssertionError("unknown annotation tag '" + c + "'");
1941         }
1942     }
1943 
1944     interface ProxyVisitor extends Attribute.Visitor {
1945         void visitEnumAttributeProxy(EnumAttributeProxy proxy);
1946         void visitClassAttributeProxy(ClassAttributeProxy proxy);
1947         void visitArrayAttributeProxy(ArrayAttributeProxy proxy);
1948         void visitCompoundAnnotationProxy(CompoundAnnotationProxy proxy);
1949     }
1950 
1951     static class EnumAttributeProxy extends Attribute {
1952         Type enumType;
1953         Name enumerator;
1954         public EnumAttributeProxy(Type enumType, Name enumerator) {
1955             super(null);
1956             this.enumType = enumType;
1957             this.enumerator = enumerator;
1958         }
1959         public void accept(Visitor v) { ((ProxyVisitor)v).visitEnumAttributeProxy(this); }
1960         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1961         public String toString() {
1962             return "/*proxy enum*/" + enumType + "." + enumerator;
1963         }
1964     }
1965 
1966     static class ClassAttributeProxy extends Attribute {
1967         Type classType;
1968         public ClassAttributeProxy(Type classType) {
1969             super(null);
1970             this.classType = classType;
1971         }
1972         public void accept(Visitor v) { ((ProxyVisitor)v).visitClassAttributeProxy(this); }
1973         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1974         public String toString() {
1975             return "/*proxy class*/" + classType + ".class";
1976         }
1977     }
1978 
1979     static class ArrayAttributeProxy extends Attribute {
1980         List<Attribute> values;
1981         ArrayAttributeProxy(List<Attribute> values) {
1982             super(null);
1983             this.values = values;
1984         }
1985         public void accept(Visitor v) { ((ProxyVisitor)v).visitArrayAttributeProxy(this); }
1986         @Override @DefinedBy(Api.LANGUAGE_MODEL)
1987         public String toString() {
1988             return "{" + values + "}";
1989         }
1990     }
1991 
1992     /** A temporary proxy representing a compound attribute.
1993      */
1994     static class CompoundAnnotationProxy extends Attribute {
1995         final List<Pair<Name,Attribute>> values;
1996         public CompoundAnnotationProxy(Type type,
1997                                       List<Pair<Name,Attribute>> values) {
1998             super(type);
1999             this.values = values;
2000         }
2001         public void accept(Visitor v) { ((ProxyVisitor)v).visitCompoundAnnotationProxy(this); }
2002         @Override @DefinedBy(Api.LANGUAGE_MODEL)
2003         public String toString() {
2004             StringBuilder buf = new StringBuilder();
2005             buf.append("@");
2006             buf.append(type.tsym.getQualifiedName());
2007             buf.append("/*proxy*/{");
2008             boolean first = true;
2009             for (List<Pair<Name,Attribute>> v = values;
2010                  v.nonEmpty(); v = v.tail) {
2011                 Pair<Name,Attribute> value = v.head;
2012                 if (!first) buf.append(",");
2013                 first = false;
2014                 buf.append(value.fst);
2015                 buf.append("=");
2016                 buf.append(value.snd);
2017             }
2018             buf.append("}");
2019             return buf.toString();
2020         }
2021     }
2022 
2023     /** A temporary proxy representing a type annotation.
2024      */
2025     static class TypeAnnotationProxy {
2026         final CompoundAnnotationProxy compound;
2027         final TypeAnnotationPosition position;
2028         public TypeAnnotationProxy(CompoundAnnotationProxy compound,
2029                 TypeAnnotationPosition position) {
2030             this.compound = compound;
2031             this.position = position;
2032         }
2033     }
2034 
2035     class AnnotationDeproxy implements ProxyVisitor {
2036         private ClassSymbol requestingOwner;
2037 
2038         AnnotationDeproxy(ClassSymbol owner) {
2039             this.requestingOwner = owner;
2040         }
2041 
2042         List<Attribute.Compound> deproxyCompoundList(List<CompoundAnnotationProxy> pl) {
2043             // also must fill in types!!!!
2044             ListBuffer<Attribute.Compound> buf = new ListBuffer<>();
2045             for (List<CompoundAnnotationProxy> l = pl; l.nonEmpty(); l=l.tail) {
2046                 buf.append(deproxyCompound(l.head));
2047             }
2048             return buf.toList();
2049         }
2050 
2051         Attribute.Compound deproxyCompound(CompoundAnnotationProxy a) {
2052             Type annotationType = resolvePossibleProxyType(a.type);
2053             ListBuffer<Pair<Symbol.MethodSymbol,Attribute>> buf = new ListBuffer<>();
2054             for (List<Pair<Name,Attribute>> l = a.values;
2055                  l.nonEmpty();
2056                  l = l.tail) {
2057                 MethodSymbol meth = findAccessMethod(annotationType, l.head.fst);
2058                 buf.append(new Pair<>(meth, deproxy(meth.type.getReturnType(), l.head.snd)));
2059             }
2060             return new Attribute.Compound(annotationType, buf.toList());
2061         }
2062 
2063         MethodSymbol findAccessMethod(Type container, Name name) {
2064             CompletionFailure failure = null;
2065             try {
2066                 for (Symbol sym : container.tsym.members().getSymbolsByName(name)) {
2067                     if (sym.kind == MTH && sym.type.getParameterTypes().length() == 0)
2068                         return (MethodSymbol) sym;
2069                 }
2070             } catch (CompletionFailure ex) {
2071                 failure = ex;
2072             }
2073             // The method wasn't found: emit a warning and recover
2074             JavaFileObject prevSource = log.useSource(requestingOwner.classfile);
2075             try {
2076                 if (failure == null) {
2077                     lint.logIfEnabled(LintWarnings.AnnotationMethodNotFound(container, name));
2078                 } else {
2079                     lint.logIfEnabled(LintWarnings.AnnotationMethodNotFoundReason(container,
2080                                                                             name,
2081                                                                             failure.getDetailValue()));//diagnostic, if present
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         lint.logIfEnabled(LintWarnings.RuntimeInvisibleParameterAnnotations(currentClassFile));
2958     }
2959     /**
2960      * Creates the parameter at the position {@code mpIndex} in the parameter list of the owning method.
2961      * Flags are optionally read from the MethodParameters attribute.
2962      * Names are optionally read from the MethodParameters attribute. If the constant pool index
2963      * of the name is 0, then the name is optionally read from the LocalVariableTable attribute.
2964      * @param mpIndex the index of the parameter in the MethodParameters attribute
2965      * @param lvtIndex the index of the parameter in the LocalVariableTable attribute
2966      */
2967     private VarSymbol parameter(int mpIndex, int lvtIndex, Type t, MethodSymbol owner, Set<Name> exclude) {
2968         long flags = PARAMETER;
2969         Name argName;
2970         if (parameterAccessFlags != null && mpIndex < parameterAccessFlags.length
2971                 && parameterAccessFlags[mpIndex] != 0) {
2972             flags |= parameterAccessFlags[mpIndex];
2973         }
2974         if (parameterNameIndicesMp != null && mpIndex < parameterNameIndicesMp.length
2975                 // if name_index is 0, then we might still get a name from the LocalVariableTable
2976                 && parameterNameIndicesMp[mpIndex] != 0) {
2977             argName = optPoolEntry(parameterNameIndicesMp[mpIndex], poolReader::getName, names.empty);
2978             flags |= NAME_FILLED;
2979         } else if (parameterNameIndicesLvt != null && lvtIndex < parameterNameIndicesLvt.length
2980                 && parameterNameIndicesLvt[lvtIndex] != 0) {
2981             argName = optPoolEntry(parameterNameIndicesLvt[lvtIndex], poolReader::getName, names.empty);
2982             flags |= NAME_FILLED;
2983         } else {
2984             String prefix = "arg";
2985             while (true) {
2986                 argName = names.fromString(prefix + exclude.size());
2987                 if (!exclude.contains(argName))
2988                     break;
2989                 prefix += "$";
2990             }
2991         }
2992         exclude.add(argName);
2993         return new ParamSymbol(flags, argName, t, owner);
2994     }
2995 
2996     /**
2997      * skip n bytes
2998      */
2999     void skipBytes(int n) {
3000         bp = bp + n;
3001     }
3002 
3003     /** Skip a field or method
3004      */
3005     void skipMember() {
3006         bp = bp + 6;
3007         char ac = nextChar();
3008         for (int i = 0; i < ac; i++) {
3009             bp = bp + 2;
3010             int attrLen = nextInt();
3011             bp = bp + attrLen;
3012         }
3013     }
3014 
3015     void skipInnerClasses() {
3016         int n = nextChar();
3017         for (int i = 0; i < n; i++) {
3018             nextChar();
3019             nextChar();
3020             nextChar();
3021             nextChar();
3022         }
3023     }
3024 
3025     /** Enter type variables of this classtype and all enclosing ones in
3026      *  `typevars'.
3027      */
3028     protected void enterTypevars(Symbol sym, Type t) {
3029         if (t.getEnclosingType() != null) {
3030             if (!t.getEnclosingType().hasTag(TypeTag.NONE)) {
3031                 enterTypevars(sym.owner, t.getEnclosingType());
3032             }
3033         } else if (sym.kind == MTH && !sym.isStatic()) {
3034             enterTypevars(sym.owner, sym.owner.type);
3035         }
3036         for (List<Type> xs = t.getTypeArguments(); xs.nonEmpty(); xs = xs.tail) {
3037             typevars.enter(xs.head.tsym);
3038         }
3039     }
3040 
3041     protected ClassSymbol enterClass(Name name) {
3042         return syms.enterClass(currentModule, name);
3043     }
3044 
3045     protected ClassSymbol enterClass(Name name, TypeSymbol owner) {
3046         return syms.enterClass(currentModule, name, owner);
3047     }
3048 
3049     /** Read contents of a given class symbol `c'. Both external and internal
3050      *  versions of an inner class are read.
3051      */
3052     void readClass(ClassSymbol c) {
3053         ClassType ct = (ClassType)c.type;
3054 
3055         // allocate scope for members
3056         c.members_field = WriteableScope.create(c);
3057 
3058         // prepare type variable table
3059         typevars = typevars.dup(currentOwner);
3060         if (ct.getEnclosingType().hasTag(CLASS))
3061             enterTypevars(c.owner, ct.getEnclosingType());
3062 
3063         // read flags, or skip if this is an inner class
3064         long f = nextChar();
3065         long flags = adjustClassFlags(f);
3066         if ((flags & MODULE) == 0) {
3067             if (c.owner.kind == PCK || c.owner.kind == ERR) c.flags_field = flags;
3068             // read own class name and check that it matches
3069             currentModule = c.packge().modle;
3070             ClassSymbol self = poolReader.getClass(nextChar());
3071             if (c != self) {
3072                 throw badClassFile("class.file.wrong.class",
3073                                    self.flatname);
3074             }
3075         } else {
3076             if (majorVersion < Version.V53.major) {
3077                 throw badClassFile("anachronistic.module.info",
3078                         Integer.toString(majorVersion),
3079                         Integer.toString(minorVersion));
3080             }
3081             c.flags_field = flags;
3082             if (c.owner.kind != MDL) {
3083                 throw badClassFile("module.info.definition.expected");
3084             }
3085             currentModule = (ModuleSymbol) c.owner;
3086             int this_class = nextChar();
3087             // temp, no check on this_class
3088         }
3089 
3090         // class attributes must be read before class
3091         // skip ahead to read class attributes
3092         int startbp = bp;
3093         nextChar();
3094         char interfaceCount = nextChar();
3095         bp += interfaceCount * 2;
3096         char fieldCount = nextChar();
3097         for (int i = 0; i < fieldCount; i++) skipMember();
3098         char methodCount = nextChar();
3099         for (int i = 0; i < methodCount; i++) skipMember();
3100         readClassAttrs(c);
3101 
3102         if (!c.getPermittedSubclasses().isEmpty()) {
3103             c.flags_field |= SEALED;
3104         }
3105 
3106         // reset and read rest of classinfo
3107         bp = startbp;
3108         int n = nextChar();
3109         if ((flags & MODULE) != 0 && n > 0) {
3110             throw badClassFile("module.info.invalid.super.class");
3111         }
3112         if (ct.supertype_field == null)
3113             ct.supertype_field =
3114                     optPoolEntry(n, idx -> poolReader.getClass(idx).erasure(types), Type.noType);
3115         n = nextChar();
3116         List<Type> is = List.nil();
3117         for (int i = 0; i < n; i++) {
3118             Type _inter = poolReader.getClass(nextChar()).erasure(types);
3119             is = is.prepend(_inter);
3120         }
3121         if (ct.interfaces_field == null)
3122             ct.interfaces_field = is.reverse();
3123 
3124         Assert.check(fieldCount == nextChar());
3125         for (int i = 0; i < fieldCount; i++) enterMember(c, readField());
3126         Assert.check(methodCount == nextChar());
3127         for (int i = 0; i < methodCount; i++) enterMember(c, readMethod());
3128         if (c.isRecord()) {
3129             for (RecordComponent rc: c.getRecordComponents()) {
3130                 rc.accessor = lookupMethod(c, rc.name, List.nil());
3131             }
3132         }
3133         typevars = typevars.leave();
3134     }
3135 
3136     private MethodSymbol lookupMethod(TypeSymbol tsym, Name name, List<Type> argtypes) {
3137         for (Symbol s : tsym.members().getSymbolsByName(name, s -> s.kind == MTH)) {
3138             if (types.isSameTypes(s.type.getParameterTypes(), argtypes)) {
3139                 return (MethodSymbol) s;
3140             }
3141         }
3142         return null;
3143     }
3144 
3145     /** Read inner class info. For each inner/outer pair allocate a
3146      *  member class.
3147      */
3148     void readInnerClasses(ClassSymbol c) {
3149         int n = nextChar();
3150         for (int i = 0; i < n; i++) {
3151             nextChar(); // skip inner class symbol
3152             int outerIdx = nextChar();
3153             int nameIdx = nextChar();
3154             ClassSymbol outer = optPoolEntry(outerIdx, poolReader::getClass, null);
3155             Name name = optPoolEntry(nameIdx, poolReader::getName, names.empty);
3156             if (name == null) name = names.empty;
3157             long flags = adjustClassFlags(nextChar());
3158             if (outer != null) { // we have a member class
3159                 if (name == names.empty)
3160                     name = names.one;
3161                 ClassSymbol member = enterClass(name, outer);
3162                 if ((flags & STATIC) == 0) {
3163                     ((ClassType)member.type).setEnclosingType(outer.type);
3164                     if (member.erasure_field != null)
3165                         ((ClassType)member.erasure_field).setEnclosingType(types.erasure(outer.type));
3166                 }
3167                 if (c == outer && member.owner == c) {
3168                     member.flags_field = flags;
3169                     enterMember(c, member);
3170                 }
3171             }
3172         }
3173     }
3174 
3175     /** Read a class definition from the bytes in buf.
3176      */
3177     private void readClassBuffer(ClassSymbol c) throws IOException {
3178         int magic = nextInt();
3179         if (magic != JAVA_MAGIC)
3180             throw badClassFile("illegal.start.of.class.file");
3181 
3182         minorVersion = nextChar();
3183         majorVersion = nextChar();
3184         int maxMajor = Version.MAX().major;
3185         int maxMinor = Version.MAX().minor;
3186         previewClassFile =
3187                 minorVersion == ClassFile.PREVIEW_MINOR_VERSION;
3188         if (majorVersion > maxMajor ||
3189             majorVersion * 1000 + minorVersion <
3190             Version.MIN().major * 1000 + Version.MIN().minor) {
3191             if (majorVersion == (maxMajor + 1) && !previewClassFile)
3192                 log.warning(Warnings.BigMajorVersion(currentClassFile,
3193                                                      majorVersion,
3194                                                      maxMajor));
3195             else
3196                 throw badClassFile("wrong.version",
3197                                    Integer.toString(majorVersion),
3198                                    Integer.toString(minorVersion),
3199                                    Integer.toString(maxMajor),
3200                                    Integer.toString(maxMinor));
3201         }
3202         utf8validation = majorVersion < V48.major ? Convert.Validation.PREJDK14 : Convert.Validation.STRICT;
3203 
3204         if (previewClassFile) {
3205             if (!preview.isEnabled()) {
3206                 log.error(preview.disabledError(currentClassFile, majorVersion));
3207             } else {
3208                 preview.warnPreview(c.classfile, majorVersion);
3209             }
3210         }
3211 
3212         poolReader = new PoolReader(this, names, syms);
3213         bp = poolReader.readPool(buf, bp);
3214         if (signatureBuffer.length < bp) {
3215             int ns = Integer.highestOneBit(bp) << 1;
3216             signatureBuffer = new byte[ns];
3217         }
3218         readClass(c);
3219     }
3220 
3221     public void readClassFile(ClassSymbol c) {
3222         currentOwner = c;
3223         currentClassFile = c.classfile;
3224         warnedAttrs.clear();
3225         filling = true;
3226         target = null;
3227         repeatable = null;
3228         try {
3229             bp = 0;
3230             buf.reset();
3231             try (InputStream input = c.classfile.openInputStream()) {
3232                 buf.appendStream(input);
3233             }
3234             readClassBuffer(c);
3235             if (!missingTypeVariables.isEmpty() && !foundTypeVariables.isEmpty()) {
3236                 List<Type> missing = missingTypeVariables;
3237                 List<Type> found = foundTypeVariables;
3238                 missingTypeVariables = List.nil();
3239                 foundTypeVariables = List.nil();
3240                 interimUses = List.nil();
3241                 interimProvides = List.nil();
3242                 filling = false;
3243                 ClassType ct = (ClassType)currentOwner.type;
3244                 ct.supertype_field =
3245                     types.subst(ct.supertype_field, missing, found);
3246                 ct.interfaces_field =
3247                     types.subst(ct.interfaces_field, missing, found);
3248                 ct.typarams_field =
3249                     types.substBounds(ct.typarams_field, missing, found);
3250                 for (List<Type> types = ct.typarams_field; types.nonEmpty(); types = types.tail) {
3251                     types.head.tsym.type = types.head;
3252                 }
3253             } else if (missingTypeVariables.isEmpty() !=
3254                        foundTypeVariables.isEmpty()) {
3255                 Name name = missingTypeVariables.head.tsym.name;
3256                 throw badClassFile("undecl.type.var", name);
3257             }
3258 
3259             if ((c.flags_field & Flags.ANNOTATION) != 0) {
3260                 c.setAnnotationTypeMetadata(new AnnotationTypeMetadata(c, new CompleterDeproxy(c, target, repeatable)));
3261             } else {
3262                 c.setAnnotationTypeMetadata(AnnotationTypeMetadata.notAnAnnotationType());
3263             }
3264 
3265             if (c == currentModule.module_info) {
3266                 if (interimUses.nonEmpty() || interimProvides.nonEmpty()) {
3267                     Assert.check(currentModule.isCompleted());
3268                     currentModule.usesProvidesCompleter =
3269                             new UsesProvidesCompleter(currentModule, interimUses, interimProvides);
3270                 } else {
3271                     currentModule.uses = List.nil();
3272                     currentModule.provides = List.nil();
3273                 }
3274             }
3275         } catch (IOException | ClosedFileSystemException ex) {
3276             throw badClassFile("unable.to.access.file", ex.toString());
3277         } catch (ArrayIndexOutOfBoundsException ex) {
3278             throw badClassFile("bad.class.file", c.flatname);
3279         } finally {
3280             interimUses = List.nil();
3281             interimProvides = List.nil();
3282             missingTypeVariables = List.nil();
3283             foundTypeVariables = List.nil();
3284             filling = false;
3285         }
3286     }
3287 
3288     /** We can only read a single class file at a time; this
3289      *  flag keeps track of when we are currently reading a class
3290      *  file.
3291      */
3292     public boolean filling = false;
3293 
3294 /* **********************************************************************
3295  * Adjusting flags
3296  ***********************************************************************/
3297 
3298     long adjustFieldFlags(long flags) {
3299         return flags;
3300     }
3301 
3302     long adjustMethodFlags(long flags) {
3303         if ((flags & ACC_BRIDGE) != 0) {
3304             flags &= ~ACC_BRIDGE;
3305             flags |= BRIDGE;
3306         }
3307         if ((flags & ACC_VARARGS) != 0) {
3308             flags &= ~ACC_VARARGS;
3309             flags |= VARARGS;
3310         }
3311         return flags;
3312     }
3313 
3314     long adjustClassFlags(long flags) {
3315         if ((flags & ACC_MODULE) != 0) {
3316             flags &= ~ACC_MODULE;
3317             flags |= MODULE;
3318         }
3319         return flags & ~ACC_SUPER; // SUPER and SYNCHRONIZED bits overloaded
3320     }
3321 
3322     /**
3323      * A subclass of JavaFileObject for the sourcefile attribute found in a classfile.
3324      * The attribute is only the last component of the original filename, so is unlikely
3325      * to be valid as is, so operations other than those to access the name throw
3326      * UnsupportedOperationException
3327      */
3328     private static class SourceFileObject implements JavaFileObject {
3329 
3330         /** The file's name.
3331          */
3332         private final Name name;
3333 
3334         public SourceFileObject(Name name) {
3335             this.name = name;
3336         }
3337 
3338         @Override @DefinedBy(Api.COMPILER)
3339         public URI toUri() {
3340             try {
3341                 return new URI(null, name.toString(), null);
3342             } catch (URISyntaxException e) {
3343                 throw new PathFileObject.CannotCreateUriError(name.toString(), e);
3344             }
3345         }
3346 
3347         @Override @DefinedBy(Api.COMPILER)
3348         public String getName() {
3349             return name.toString();
3350         }
3351 
3352         @Override @DefinedBy(Api.COMPILER)
3353         public JavaFileObject.Kind getKind() {
3354             return BaseFileManager.getKind(getName());
3355         }
3356 
3357         @Override @DefinedBy(Api.COMPILER)
3358         public InputStream openInputStream() {
3359             throw new UnsupportedOperationException();
3360         }
3361 
3362         @Override @DefinedBy(Api.COMPILER)
3363         public OutputStream openOutputStream() {
3364             throw new UnsupportedOperationException();
3365         }
3366 
3367         @Override @DefinedBy(Api.COMPILER)
3368         public CharBuffer getCharContent(boolean ignoreEncodingErrors) {
3369             throw new UnsupportedOperationException();
3370         }
3371 
3372         @Override @DefinedBy(Api.COMPILER)
3373         public Reader openReader(boolean ignoreEncodingErrors) {
3374             throw new UnsupportedOperationException();
3375         }
3376 
3377         @Override @DefinedBy(Api.COMPILER)
3378         public Writer openWriter() {
3379             throw new UnsupportedOperationException();
3380         }
3381 
3382         @Override @DefinedBy(Api.COMPILER)
3383         public long getLastModified() {
3384             throw new UnsupportedOperationException();
3385         }
3386 
3387         @Override @DefinedBy(Api.COMPILER)
3388         public boolean delete() {
3389             throw new UnsupportedOperationException();
3390         }
3391 
3392         @Override @DefinedBy(Api.COMPILER)
3393         public boolean isNameCompatible(String simpleName, JavaFileObject.Kind kind) {
3394             return true; // fail-safe mode
3395         }
3396 
3397         @Override @DefinedBy(Api.COMPILER)
3398         public NestingKind getNestingKind() {
3399             return null;
3400         }
3401 
3402         @Override @DefinedBy(Api.COMPILER)
3403         public Modifier getAccessLevel() {
3404             return null;
3405         }
3406 
3407         /**
3408          * Check if two file objects are equal.
3409          * SourceFileObjects are just placeholder objects for the value of a
3410          * SourceFile attribute, and do not directly represent specific files.
3411          * Two SourceFileObjects are equal if their names are equal.
3412          */
3413         @Override
3414         public boolean equals(Object other) {
3415             if (this == other)
3416                 return true;
3417             return (other instanceof SourceFileObject sourceFileObject)
3418                     && name.equals(sourceFileObject.name);
3419         }
3420 
3421         @Override
3422         public int hashCode() {
3423             return name.hashCode();
3424         }
3425     }
3426 
3427     private class CompleterDeproxy implements AnnotationTypeCompleter {
3428         ClassSymbol proxyOn;
3429         CompoundAnnotationProxy target;
3430         CompoundAnnotationProxy repeatable;
3431 
3432         public CompleterDeproxy(ClassSymbol c, CompoundAnnotationProxy target,
3433                 CompoundAnnotationProxy repeatable)
3434         {
3435             this.proxyOn = c;
3436             this.target = target;
3437             this.repeatable = repeatable;
3438         }
3439 
3440         @Override
3441         public void complete(ClassSymbol sym) {
3442             Assert.check(proxyOn == sym);
3443             Attribute.Compound theTarget = null, theRepeatable = null;
3444             AnnotationDeproxy deproxy;
3445 
3446             try {
3447                 if (target != null) {
3448                     deproxy = new AnnotationDeproxy(proxyOn);
3449                     theTarget = deproxy.deproxyCompound(target);
3450                 }
3451 
3452                 if (repeatable != null) {
3453                     deproxy = new AnnotationDeproxy(proxyOn);
3454                     theRepeatable = deproxy.deproxyCompound(repeatable);
3455                 }
3456             } catch (Exception e) {
3457                 throw new CompletionFailure(sym,
3458                                             () -> ClassReader.this.diagFactory.fragment(Fragments.ExceptionMessage(e.getMessage())),
3459                                             dcfh);
3460             }
3461 
3462             sym.getAnnotationTypeMetadata().setTarget(theTarget);
3463             sym.getAnnotationTypeMetadata().setRepeatable(theRepeatable);
3464         }
3465     }
3466 
3467     private class ProxyType extends Type {
3468 
3469         private final Name name;
3470 
3471         public ProxyType(int index) {
3472             super(syms.noSymbol, List.nil());
3473             this.name = poolReader.getName(index);
3474         }
3475 
3476         @Override
3477         public TypeTag getTag() {
3478             return TypeTag.NONE;
3479         }
3480 
3481         public Type resolve() {
3482             return name.map(ClassReader.this::sigToType);
3483         }
3484 
3485         @Override @DefinedBy(Api.LANGUAGE_MODEL)
3486         public String toString() {
3487             return "<ProxyType>";
3488         }
3489 
3490     }
3491 
3492     private static final class InterimUsesDirective {
3493         public final Name service;
3494 
3495         public InterimUsesDirective(Name service) {
3496             this.service = service;
3497         }
3498 
3499     }
3500 
3501     private static final class InterimProvidesDirective {
3502         public final Name service;
3503         public final List<Name> impls;
3504 
3505         public InterimProvidesDirective(Name service, List<Name> impls) {
3506             this.service = service;
3507             this.impls = impls;
3508         }
3509 
3510     }
3511 
3512     private final class UsesProvidesCompleter implements Completer {
3513         private final ModuleSymbol currentModule;
3514         private final List<InterimUsesDirective> interimUsesCopy;
3515         private final List<InterimProvidesDirective> interimProvidesCopy;
3516 
3517         public UsesProvidesCompleter(ModuleSymbol currentModule, List<InterimUsesDirective> interimUsesCopy, List<InterimProvidesDirective> interimProvidesCopy) {
3518             this.currentModule = currentModule;
3519             this.interimUsesCopy = interimUsesCopy;
3520             this.interimProvidesCopy = interimProvidesCopy;
3521         }
3522 
3523         @Override
3524         public void complete(Symbol sym) throws CompletionFailure {
3525             ListBuffer<Directive> directives = new ListBuffer<>();
3526             directives.addAll(currentModule.directives);
3527             ListBuffer<UsesDirective> uses = new ListBuffer<>();
3528             for (InterimUsesDirective interim : interimUsesCopy) {
3529                 UsesDirective d = new UsesDirective(syms.enterClass(currentModule, interim.service));
3530                 uses.add(d);
3531                 directives.add(d);
3532             }
3533             currentModule.uses = uses.toList();
3534             ListBuffer<ProvidesDirective> provides = new ListBuffer<>();
3535             for (InterimProvidesDirective interim : interimProvidesCopy) {
3536                 ListBuffer<ClassSymbol> impls = new ListBuffer<>();
3537                 for (Name impl : interim.impls) {
3538                     impls.append(syms.enterClass(currentModule, impl));
3539                 }
3540                 ProvidesDirective d = new ProvidesDirective(syms.enterClass(currentModule, interim.service),
3541                                                             impls.toList());
3542                 provides.add(d);
3543                 directives.add(d);
3544             }
3545             currentModule.provides = provides.toList();
3546             currentModule.directives = directives.toList();
3547         }
3548     }
3549 }