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