1 /*
   2  * Copyright (c) 1999, 2021, 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.util.LinkedHashMap;
  30 import java.util.Map;
  31 import java.util.Set;
  32 import java.util.LinkedHashSet;
  33 import java.util.function.ToIntFunction;
  34 
  35 import javax.tools.JavaFileManager;
  36 import javax.tools.FileObject;
  37 import javax.tools.JavaFileManager.Location;
  38 import javax.tools.JavaFileObject;
  39 
  40 import com.sun.tools.javac.code.*;
  41 import com.sun.tools.javac.code.Attribute.RetentionPolicy;
  42 import com.sun.tools.javac.code.Directive.*;
  43 import com.sun.tools.javac.code.Scope.WriteableScope;
  44 import com.sun.tools.javac.code.Source.Feature;
  45 import com.sun.tools.javac.code.Symbol.*;
  46 import com.sun.tools.javac.code.Type.*;
  47 import com.sun.tools.javac.code.Types.SignatureGenerator.InvalidSignatureException;
  48 import com.sun.tools.javac.comp.Check;
  49 import com.sun.tools.javac.file.PathFileObject;
  50 import com.sun.tools.javac.jvm.PoolConstant.LoadableConstant;
  51 import com.sun.tools.javac.jvm.PoolConstant.Dynamic.BsmKey;
  52 import com.sun.tools.javac.resources.CompilerProperties.Errors;
  53 import com.sun.tools.javac.resources.CompilerProperties.Fragments;
  54 import com.sun.tools.javac.util.*;
  55 import com.sun.tools.javac.util.List;
  56 
  57 import static com.sun.tools.javac.code.Flags.*;
  58 import static com.sun.tools.javac.code.Kinds.Kind.*;
  59 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
  60 import static com.sun.tools.javac.code.TypeTag.*;
  61 import static com.sun.tools.javac.main.Option.*;
  62 
  63 import static javax.tools.StandardLocation.CLASS_OUTPUT;
  64 
  65 /** This class provides operations to map an internal symbol table graph
  66  *  rooted in a ClassSymbol into a classfile.
  67  *
  68  *  <p><b>This is NOT part of any supported API.
  69  *  If you write code that depends on this, you do so at your own risk.
  70  *  This code and its internal interfaces are subject to change or
  71  *  deletion without notice.</b>
  72  */
  73 public class ClassWriter extends ClassFile {
  74     protected static final Context.Key<ClassWriter> classWriterKey = new Context.Key<>();
  75 
  76     private final Options options;
  77 
  78     /** Switch: verbose output.
  79      */
  80     private boolean verbose;
  81 
  82     /** Switch: emit source file attribute.
  83      */
  84     private boolean emitSourceFile;
  85 
  86     /** Switch: generate CharacterRangeTable attribute.
  87      */
  88     private boolean genCrt;
  89 
  90     /** Switch: describe the generated stackmap.
  91      */
  92     private boolean debugstackmap;
  93 
  94     /** Preview language level.
  95      */
  96     private Preview preview;
  97 
  98     /**
  99      * Target class version.
 100      */
 101     private Target target;
 102 
 103     /**
 104      * Source language version.
 105      */
 106     private Source source;
 107 
 108     /** Type utilities. */
 109     private Types types;
 110 
 111     private Check check;
 112 
 113     /**
 114      * If true, class files will be written in module-specific subdirectories
 115      * of the CLASS_OUTPUT location.
 116      */
 117     public boolean multiModuleMode;
 118 
 119     private List<ToIntFunction<Symbol>> extraAttributeHooks = List.nil();
 120 
 121     /** The initial sizes of the data and constant pool buffers.
 122      *  Sizes are increased when buffers get full.
 123      */
 124     static final int DATA_BUF_SIZE = 0x0fff0;
 125     static final int CLASS_BUF_SIZE = 0x1fff0;
 126 
 127     /** An output buffer for member info.
 128      */
 129     public ByteBuffer databuf = new ByteBuffer(DATA_BUF_SIZE);
 130 
 131     /** An output buffer for the constant pool.
 132      */
 133     ByteBuffer poolbuf = new ByteBuffer(CLASS_BUF_SIZE);
 134 
 135     /** The constant pool writer.
 136      */
 137     final PoolWriter poolWriter;
 138 
 139     /** The log to use for verbose output.
 140      */
 141     private final Log log;
 142 
 143     /** The name table. */
 144     private final Names names;
 145 
 146     private final Symtab syms;
 147 
 148     /** Access to files. */
 149     private final JavaFileManager fileManager;
 150 
 151     /** The tags and constants used in compressed stackmap. */
 152     static final int SAME_FRAME_SIZE = 64;
 153     static final int SAME_LOCALS_1_STACK_ITEM_EXTENDED = 247;
 154     static final int SAME_FRAME_EXTENDED = 251;
 155     static final int FULL_FRAME = 255;
 156     static final int MAX_LOCAL_LENGTH_DIFF = 4;
 157 
 158     /** Get the ClassWriter instance for this context. */
 159     public static ClassWriter instance(Context context) {
 160         ClassWriter instance = context.get(classWriterKey);
 161         if (instance == null)
 162             instance = new ClassWriter(context);
 163         return instance;
 164     }
 165 
 166     /** Construct a class writer, given an options table.
 167      */
 168     protected ClassWriter(Context context) {
 169         context.put(classWriterKey, this);
 170 
 171         log = Log.instance(context);
 172         names = Names.instance(context);
 173         options = Options.instance(context);
 174         preview = Preview.instance(context);
 175         target = Target.instance(context);
 176         source = Source.instance(context);
 177         types = Types.instance(context);
 178         check = Check.instance(context);
 179         fileManager = context.get(JavaFileManager.class);
 180         poolWriter = Gen.instance(context).poolWriter;
 181         syms = Symtab.instance(context);
 182 
 183         verbose        = options.isSet(VERBOSE);
 184         genCrt         = options.isSet(XJCOV);
 185         debugstackmap = options.isSet("debug.stackmap");
 186 
 187         emitSourceFile = options.isUnset(G_CUSTOM) ||
 188                             options.isSet(G_CUSTOM, "source");
 189 
 190         String modifierFlags = options.get("debug.dumpmodifiers");
 191         if (modifierFlags != null) {
 192             dumpClassModifiers = modifierFlags.indexOf('c') != -1;
 193             dumpFieldModifiers = modifierFlags.indexOf('f') != -1;
 194             dumpInnerClassModifiers = modifierFlags.indexOf('i') != -1;
 195             dumpMethodModifiers = modifierFlags.indexOf('m') != -1;
 196         }
 197     }
 198 
 199     public void addExtraAttributes(ToIntFunction<Symbol> addExtraAttributes) {
 200         extraAttributeHooks = extraAttributeHooks.prepend(addExtraAttributes);
 201     }
 202 
 203 /******************************************************************
 204  * Diagnostics: dump generated class names and modifiers
 205  ******************************************************************/
 206 
 207     /** Value of option 'dumpmodifiers' is a string
 208      *  indicating which modifiers should be dumped for debugging:
 209      *    'c' -- classes
 210      *    'f' -- fields
 211      *    'i' -- innerclass attributes
 212      *    'm' -- methods
 213      *  For example, to dump everything:
 214      *    javac -XDdumpmodifiers=cifm MyProg.java
 215      */
 216     private boolean dumpClassModifiers; // -XDdumpmodifiers=c
 217     private boolean dumpFieldModifiers; // -XDdumpmodifiers=f
 218     private boolean dumpInnerClassModifiers; // -XDdumpmodifiers=i
 219     private boolean dumpMethodModifiers; // -XDdumpmodifiers=m
 220 
 221     /** Return flags as a string, separated by " ".
 222      */
 223     public static String flagNames(long flags) {
 224         StringBuilder sbuf = new StringBuilder();
 225         int i = 0;
 226         long f = flags & StandardFlags;
 227         while (f != 0) {
 228             if ((f & 1) != 0) {
 229                 sbuf.append(" ");
 230                 sbuf.append(flagName[i]);
 231             }
 232             f = f >> 1;
 233             i++;
 234         }
 235         return sbuf.toString();
 236     }
 237     //where
 238         private static final String[] flagName = {
 239             "PUBLIC", "PRIVATE", "PROTECTED", "STATIC", "FINAL",
 240             "IDENTITY", "VOLATILE", "TRANSIENT", "NATIVE", "INTERFACE",
 241             "ABSTRACT", "STRICTFP"};
 242 
 243 /******************************************************************
 244  * Output routines
 245  ******************************************************************/
 246 
 247     /** Write a character into given byte buffer;
 248      *  byte buffer will not be grown.
 249      */
 250     void putChar(ByteBuffer buf, int op, int x) {
 251         buf.elems[op  ] = (byte)((x >>  8) & 0xFF);
 252         buf.elems[op+1] = (byte)((x      ) & 0xFF);
 253     }
 254 
 255     /** Write an integer into given byte buffer;
 256      *  byte buffer will not be grown.
 257      */
 258     void putInt(ByteBuffer buf, int adr, int x) {
 259         buf.elems[adr  ] = (byte)((x >> 24) & 0xFF);
 260         buf.elems[adr+1] = (byte)((x >> 16) & 0xFF);
 261         buf.elems[adr+2] = (byte)((x >>  8) & 0xFF);
 262         buf.elems[adr+3] = (byte)((x      ) & 0xFF);
 263     }
 264 
 265 /******************************************************************
 266  * Writing the Constant Pool
 267  ******************************************************************/
 268 
 269     /** Thrown when the constant pool is over full.
 270      */
 271     public static class PoolOverflow extends RuntimeException {
 272         private static final long serialVersionUID = 0;
 273         public PoolOverflow() {}
 274     }
 275     public static class StringOverflow extends RuntimeException {
 276         private static final long serialVersionUID = 0;
 277         public final String value;
 278         public StringOverflow(String s) {
 279             value = s;
 280         }
 281     }
 282 
 283 /******************************************************************
 284  * Writing Attributes
 285  ******************************************************************/
 286 
 287     /** Write header for an attribute to data buffer and return
 288      *  position past attribute length index.
 289      */
 290     public int writeAttr(Name attrName) {
 291         int index = poolWriter.putName(attrName);
 292         databuf.appendChar(index);
 293         databuf.appendInt(0);
 294         return databuf.length;
 295     }
 296 
 297     /** Fill in attribute length.
 298      */
 299     public void endAttr(int index) {
 300         putInt(databuf, index - 4, databuf.length - index);
 301     }
 302 
 303     /** Leave space for attribute count and return index for
 304      *  number of attributes field.
 305      */
 306     int beginAttrs() {
 307         databuf.appendChar(0);
 308         return databuf.length;
 309     }
 310 
 311     /** Fill in number of attributes.
 312      */
 313     void endAttrs(int index, int count) {
 314         putChar(databuf, index - 2, count);
 315     }
 316 
 317     /** Write the EnclosingMethod attribute if needed.
 318      *  Returns the number of attributes written (0 or 1).
 319      */
 320     int writeEnclosingMethodAttribute(ClassSymbol c) {
 321         return writeEnclosingMethodAttribute(names.EnclosingMethod, c);
 322     }
 323 
 324     /** Write the EnclosingMethod attribute with a specified name.
 325      *  Returns the number of attributes written (0 or 1).
 326      */
 327     protected int writeEnclosingMethodAttribute(Name attributeName, ClassSymbol c) {
 328         if (c.owner.kind != MTH && // neither a local class
 329             c.name != names.empty) // nor anonymous
 330             return 0;
 331 
 332         int alenIdx = writeAttr(attributeName);
 333         ClassSymbol enclClass = c.owner.enclClass();
 334         MethodSymbol enclMethod =
 335             (c.owner.type == null // local to init block
 336              || c.owner.kind != MTH) // or member init
 337             ? null
 338             : ((MethodSymbol)c.owner).originalEnclosingMethod();
 339         databuf.appendChar(poolWriter.putClass(enclClass));
 340         databuf.appendChar(enclMethod == null ? 0 : poolWriter.putNameAndType(enclMethod));
 341         endAttr(alenIdx);
 342         return 1;
 343     }
 344 
 345     /** Write flag attributes; return number of attributes written.
 346      */
 347     int writeFlagAttrs(long flags) {
 348         int acount = 0;
 349         if ((flags & DEPRECATED) != 0) {
 350             int alenIdx = writeAttr(names.Deprecated);
 351             endAttr(alenIdx);
 352             acount++;
 353         }
 354         return acount;
 355     }
 356 
 357     /** Write member (field or method) attributes;
 358      *  return number of attributes written.
 359      */
 360     int writeMemberAttrs(Symbol sym, boolean isRecordComponent) {
 361         int acount = 0;
 362         if (!isRecordComponent) {
 363             acount = writeFlagAttrs(sym.flags());
 364         }
 365         long flags = sym.flags();
 366         if ((flags & (SYNTHETIC | BRIDGE)) != SYNTHETIC &&
 367             (flags & ANONCONSTR) == 0 &&
 368             (!types.isSameType(sym.type, sym.erasure(types)) ||
 369              poolWriter.signatureGen.hasTypeVar(sym.type.getThrownTypes()))) {
 370             // note that a local class with captured variables
 371             // will get a signature attribute
 372             int alenIdx = writeAttr(names.Signature);
 373             databuf.appendChar(poolWriter.putSignature(sym));
 374             endAttr(alenIdx);
 375             acount++;
 376         }
 377         acount += writeJavaAnnotations(sym.getRawAttributes());
 378         acount += writeTypeAnnotations(sym.getRawTypeAttributes(), false);
 379         return acount;
 380     }
 381 
 382     /**
 383      * Write method parameter names attribute.
 384      */
 385     int writeMethodParametersAttr(MethodSymbol m) {
 386         MethodType ty = m.externalType(types).asMethodType();
 387         final int allparams = ty.argtypes.size();
 388         if (m.params != null && allparams != 0) {
 389             final int attrIndex = writeAttr(names.MethodParameters);
 390             databuf.appendByte(allparams);
 391             // Write extra parameters first
 392             for (VarSymbol s : m.extraParams) {
 393                 final int flags =
 394                     ((int) s.flags() & (FINAL | SYNTHETIC | MANDATED)) |
 395                     ((int) m.flags() & SYNTHETIC);
 396                 databuf.appendChar(poolWriter.putName(s.name));
 397                 databuf.appendChar(flags);
 398             }
 399             // Now write the real parameters
 400             for (VarSymbol s : m.params) {
 401                 final int flags =
 402                     ((int) s.flags() & (FINAL | SYNTHETIC | MANDATED)) |
 403                     ((int) m.flags() & SYNTHETIC);
 404                 databuf.appendChar(poolWriter.putName(s.name));
 405                 databuf.appendChar(flags);
 406             }
 407             // Now write the captured locals
 408             for (VarSymbol s : m.capturedLocals) {
 409                 final int flags =
 410                     ((int) s.flags() & (FINAL | SYNTHETIC | MANDATED)) |
 411                     ((int) m.flags() & SYNTHETIC);
 412                 databuf.appendChar(poolWriter.putName(s.name));
 413                 databuf.appendChar(flags);
 414             }
 415             endAttr(attrIndex);
 416             return 1;
 417         } else
 418             return 0;
 419     }
 420 
 421     private void writeParamAnnotations(List<VarSymbol> params,
 422                                        RetentionPolicy retention) {
 423         databuf.appendByte(params.length());
 424         for (VarSymbol s : params) {
 425             ListBuffer<Attribute.Compound> buf = new ListBuffer<>();
 426             for (Attribute.Compound a : s.getRawAttributes())
 427                 if (types.getRetention(a) == retention)
 428                     buf.append(a);
 429             databuf.appendChar(buf.length());
 430             for (Attribute.Compound a : buf)
 431                 writeCompoundAttribute(a);
 432         }
 433 
 434     }
 435 
 436     private void writeParamAnnotations(MethodSymbol m,
 437                                        RetentionPolicy retention) {
 438         databuf.appendByte(m.params.length());
 439         writeParamAnnotations(m.params, retention);
 440     }
 441 
 442     /** Write method parameter annotations;
 443      *  return number of attributes written.
 444      */
 445     int writeParameterAttrs(List<VarSymbol> vars) {
 446         boolean hasVisible = false;
 447         boolean hasInvisible = false;
 448         if (vars != null) {
 449             for (VarSymbol s : vars) {
 450                 for (Attribute.Compound a : s.getRawAttributes()) {
 451                     switch (types.getRetention(a)) {
 452                     case SOURCE: break;
 453                     case CLASS: hasInvisible = true; break;
 454                     case RUNTIME: hasVisible = true; break;
 455                     default: // /* fail soft */ throw new AssertionError(vis);
 456                     }
 457                 }
 458             }
 459         }
 460 
 461         int attrCount = 0;
 462         if (hasVisible) {
 463             int attrIndex = writeAttr(names.RuntimeVisibleParameterAnnotations);
 464             writeParamAnnotations(vars, RetentionPolicy.RUNTIME);
 465             endAttr(attrIndex);
 466             attrCount++;
 467         }
 468         if (hasInvisible) {
 469             int attrIndex = writeAttr(names.RuntimeInvisibleParameterAnnotations);
 470             writeParamAnnotations(vars, RetentionPolicy.CLASS);
 471             endAttr(attrIndex);
 472             attrCount++;
 473         }
 474         return attrCount;
 475     }
 476 
 477 /**********************************************************************
 478  * Writing Java-language annotations (aka metadata, attributes)
 479  **********************************************************************/
 480 
 481     /** Write Java-language annotations; return number of JVM
 482      *  attributes written (zero or one).
 483      */
 484     int writeJavaAnnotations(List<Attribute.Compound> attrs) {
 485         if (attrs.isEmpty()) return 0;
 486         ListBuffer<Attribute.Compound> visibles = new ListBuffer<>();
 487         ListBuffer<Attribute.Compound> invisibles = new ListBuffer<>();
 488         for (Attribute.Compound a : attrs) {
 489             switch (types.getRetention(a)) {
 490             case SOURCE: break;
 491             case CLASS: invisibles.append(a); break;
 492             case RUNTIME: visibles.append(a); break;
 493             default: // /* fail soft */ throw new AssertionError(vis);
 494             }
 495         }
 496 
 497         int attrCount = 0;
 498         if (visibles.length() != 0) {
 499             int attrIndex = writeAttr(names.RuntimeVisibleAnnotations);
 500             databuf.appendChar(visibles.length());
 501             for (Attribute.Compound a : visibles)
 502                 writeCompoundAttribute(a);
 503             endAttr(attrIndex);
 504             attrCount++;
 505         }
 506         if (invisibles.length() != 0) {
 507             int attrIndex = writeAttr(names.RuntimeInvisibleAnnotations);
 508             databuf.appendChar(invisibles.length());
 509             for (Attribute.Compound a : invisibles)
 510                 writeCompoundAttribute(a);
 511             endAttr(attrIndex);
 512             attrCount++;
 513         }
 514         return attrCount;
 515     }
 516 
 517     int writeTypeAnnotations(List<Attribute.TypeCompound> typeAnnos, boolean inCode) {
 518         if (typeAnnos.isEmpty()) return 0;
 519 
 520         ListBuffer<Attribute.TypeCompound> visibles = new ListBuffer<>();
 521         ListBuffer<Attribute.TypeCompound> invisibles = new ListBuffer<>();
 522 
 523         for (Attribute.TypeCompound tc : typeAnnos) {
 524             if (tc.hasUnknownPosition()) {
 525                 boolean fixed = tc.tryFixPosition();
 526 
 527                 // Could we fix it?
 528                 if (!fixed) {
 529                     // This happens for nested types like @A Outer. @B Inner.
 530                     // For method parameters we get the annotation twice! Once with
 531                     // a valid position, once unknown.
 532                     // TODO: find a cleaner solution.
 533                     PrintWriter pw = log.getWriter(Log.WriterKind.ERROR);
 534                     pw.println("ClassWriter: Position UNKNOWN in type annotation: " + tc);
 535                     continue;
 536                 }
 537             }
 538 
 539             if (tc.position.type.isLocal() != inCode)
 540                 continue;
 541             if (!tc.position.emitToClassfile())
 542                 continue;
 543             switch (types.getRetention(tc)) {
 544             case SOURCE: break;
 545             case CLASS: invisibles.append(tc); break;
 546             case RUNTIME: visibles.append(tc); break;
 547             default: // /* fail soft */ throw new AssertionError(vis);
 548             }
 549         }
 550 
 551         int attrCount = 0;
 552         if (visibles.length() != 0) {
 553             int attrIndex = writeAttr(names.RuntimeVisibleTypeAnnotations);
 554             databuf.appendChar(visibles.length());
 555             for (Attribute.TypeCompound p : visibles)
 556                 writeTypeAnnotation(p);
 557             endAttr(attrIndex);
 558             attrCount++;
 559         }
 560 
 561         if (invisibles.length() != 0) {
 562             int attrIndex = writeAttr(names.RuntimeInvisibleTypeAnnotations);
 563             databuf.appendChar(invisibles.length());
 564             for (Attribute.TypeCompound p : invisibles)
 565                 writeTypeAnnotation(p);
 566             endAttr(attrIndex);
 567             attrCount++;
 568         }
 569 
 570         return attrCount;
 571     }
 572 
 573     /** A visitor to write an attribute including its leading
 574      *  single-character marker.
 575      */
 576     class AttributeWriter implements Attribute.Visitor {
 577         public void visitConstant(Attribute.Constant _value) {
 578             if (_value.type.getTag() == CLASS) {
 579                 Assert.check(_value.value instanceof String);
 580                 String s = (String)_value.value;
 581                 databuf.appendByte('s');
 582                 databuf.appendChar(poolWriter.putName(names.fromString(s)));
 583             } else {
 584                 switch (_value.type.getTag()) {
 585                     case BYTE:
 586                         databuf.appendByte('B');
 587                         break;
 588                     case CHAR:
 589                         databuf.appendByte('C');
 590                         break;
 591                     case SHORT:
 592                         databuf.appendByte('S');
 593                         break;
 594                     case INT:
 595                         databuf.appendByte('I');
 596                         break;
 597                     case LONG:
 598                         databuf.appendByte('J');
 599                         break;
 600                     case FLOAT:
 601                         databuf.appendByte('F');
 602                         break;
 603                     case DOUBLE:
 604                         databuf.appendByte('D');
 605                         break;
 606                     case BOOLEAN:
 607                         databuf.appendByte('Z');
 608                         break;
 609                     default:
 610                         throw new AssertionError(_value.type);
 611                 }
 612                 databuf.appendChar(poolWriter.putConstant(_value.value));
 613             }
 614         }
 615         public void visitEnum(Attribute.Enum e) {
 616             databuf.appendByte('e');
 617             databuf.appendChar(poolWriter.putDescriptor(e.value.type));
 618             databuf.appendChar(poolWriter.putName(e.value.name));
 619         }
 620         public void visitClass(Attribute.Class clazz) {
 621             databuf.appendByte('c');
 622             databuf.appendChar(poolWriter.putDescriptor(clazz.classType));
 623         }
 624         public void visitCompound(Attribute.Compound compound) {
 625             databuf.appendByte('@');
 626             writeCompoundAttribute(compound);
 627         }
 628         public void visitError(Attribute.Error x) {
 629             throw new AssertionError(x);
 630         }
 631         public void visitArray(Attribute.Array array) {
 632             databuf.appendByte('[');
 633             databuf.appendChar(array.values.length);
 634             for (Attribute a : array.values) {
 635                 a.accept(this);
 636             }
 637         }
 638     }
 639     AttributeWriter awriter = new AttributeWriter();
 640 
 641     /** Write a compound attribute excluding the '@' marker. */
 642     void writeCompoundAttribute(Attribute.Compound c) {
 643         databuf.appendChar(poolWriter.putDescriptor(c.type));
 644         databuf.appendChar(c.values.length());
 645         for (Pair<Symbol.MethodSymbol,Attribute> p : c.values) {
 646             databuf.appendChar(poolWriter.putName(p.fst.name));
 647             p.snd.accept(awriter);
 648         }
 649     }
 650 
 651     void writeTypeAnnotation(Attribute.TypeCompound c) {
 652         writePosition(c.position);
 653         writeCompoundAttribute(c);
 654     }
 655 
 656     void writePosition(TypeAnnotationPosition p) {
 657         databuf.appendByte(p.type.targetTypeValue()); // TargetType tag is a byte
 658         switch (p.type) {
 659         // instanceof
 660         case INSTANCEOF:
 661         // new expression
 662         case NEW:
 663         // constructor/method reference receiver
 664         case CONSTRUCTOR_REFERENCE:
 665         case METHOD_REFERENCE:
 666             databuf.appendChar(p.offset);
 667             break;
 668         // local variable
 669         case LOCAL_VARIABLE:
 670         // resource variable
 671         case RESOURCE_VARIABLE:
 672             databuf.appendChar(p.lvarOffset.length);  // for table length
 673             for (int i = 0; i < p.lvarOffset.length; ++i) {
 674                 databuf.appendChar(p.lvarOffset[i]);
 675                 databuf.appendChar(p.lvarLength[i]);
 676                 databuf.appendChar(p.lvarIndex[i]);
 677             }
 678             break;
 679         // exception parameter
 680         case EXCEPTION_PARAMETER:
 681             databuf.appendChar(p.getExceptionIndex());
 682             break;
 683         // method receiver
 684         case METHOD_RECEIVER:
 685             // Do nothing
 686             break;
 687         // type parameter
 688         case CLASS_TYPE_PARAMETER:
 689         case METHOD_TYPE_PARAMETER:
 690             databuf.appendByte(p.parameter_index);
 691             break;
 692         // type parameter bound
 693         case CLASS_TYPE_PARAMETER_BOUND:
 694         case METHOD_TYPE_PARAMETER_BOUND:
 695             databuf.appendByte(p.parameter_index);
 696             databuf.appendByte(p.bound_index);
 697             break;
 698         // class extends or implements clause
 699         case CLASS_EXTENDS:
 700             databuf.appendChar(p.type_index);
 701             break;
 702         // throws
 703         case THROWS:
 704             databuf.appendChar(p.type_index);
 705             break;
 706         // method parameter
 707         case METHOD_FORMAL_PARAMETER:
 708             databuf.appendByte(p.parameter_index);
 709             break;
 710         // type cast
 711         case CAST:
 712         // method/constructor/reference type argument
 713         case CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT:
 714         case METHOD_INVOCATION_TYPE_ARGUMENT:
 715         case CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT:
 716         case METHOD_REFERENCE_TYPE_ARGUMENT:
 717             databuf.appendChar(p.offset);
 718             databuf.appendByte(p.type_index);
 719             break;
 720         // We don't need to worry about these
 721         case METHOD_RETURN:
 722         case FIELD:
 723             break;
 724         case UNKNOWN:
 725             throw new AssertionError("jvm.ClassWriter: UNKNOWN target type should never occur!");
 726         default:
 727             throw new AssertionError("jvm.ClassWriter: Unknown target type for position: " + p);
 728         }
 729 
 730         { // Append location data for generics/arrays.
 731             databuf.appendByte(p.location.size());
 732             java.util.List<Integer> loc = TypeAnnotationPosition.getBinaryFromTypePath(p.location);
 733             for (int i : loc)
 734                 databuf.appendByte((byte)i);
 735         }
 736     }
 737 
 738 /**********************************************************************
 739  * Writing module attributes
 740  **********************************************************************/
 741 
 742     /** Write the Module attribute if needed.
 743      *  Returns the number of attributes written (0 or 1).
 744      */
 745     int writeModuleAttribute(ClassSymbol c) {
 746         ModuleSymbol m = (ModuleSymbol) c.owner;
 747 
 748         int alenIdx = writeAttr(names.Module);
 749 
 750         databuf.appendChar(poolWriter.putModule(m));
 751         databuf.appendChar(ModuleFlags.value(m.flags)); // module_flags
 752         databuf.appendChar(m.version != null ? poolWriter.putName(m.version) : 0);
 753 
 754         ListBuffer<RequiresDirective> requires = new ListBuffer<>();
 755         for (RequiresDirective r: m.requires) {
 756             if (!r.flags.contains(RequiresFlag.EXTRA))
 757                 requires.add(r);
 758         }
 759         databuf.appendChar(requires.size());
 760         for (RequiresDirective r: requires) {
 761             databuf.appendChar(poolWriter.putModule(r.module));
 762             databuf.appendChar(RequiresFlag.value(r.flags));
 763             databuf.appendChar(r.module.version != null ? poolWriter.putName(r.module.version) : 0);
 764         }
 765 
 766         List<ExportsDirective> exports = m.exports;
 767         databuf.appendChar(exports.size());
 768         for (ExportsDirective e: exports) {
 769             databuf.appendChar(poolWriter.putPackage(e.packge));
 770             databuf.appendChar(ExportsFlag.value(e.flags));
 771             if (e.modules == null) {
 772                 databuf.appendChar(0);
 773             } else {
 774                 databuf.appendChar(e.modules.size());
 775                 for (ModuleSymbol msym: e.modules) {
 776                     databuf.appendChar(poolWriter.putModule(msym));
 777                 }
 778             }
 779         }
 780 
 781         List<OpensDirective> opens = m.opens;
 782         databuf.appendChar(opens.size());
 783         for (OpensDirective o: opens) {
 784             databuf.appendChar(poolWriter.putPackage(o.packge));
 785             databuf.appendChar(OpensFlag.value(o.flags));
 786             if (o.modules == null) {
 787                 databuf.appendChar(0);
 788             } else {
 789                 databuf.appendChar(o.modules.size());
 790                 for (ModuleSymbol msym: o.modules) {
 791                     databuf.appendChar(poolWriter.putModule(msym));
 792                 }
 793             }
 794         }
 795 
 796         List<UsesDirective> uses = m.uses;
 797         databuf.appendChar(uses.size());
 798         for (UsesDirective s: uses) {
 799             databuf.appendChar(poolWriter.putClass(s.service));
 800         }
 801 
 802         // temporary fix to merge repeated provides clause for same service;
 803         // eventually this should be disallowed when analyzing the module,
 804         // so that each service type only appears once.
 805         Map<ClassSymbol, Set<ClassSymbol>> mergedProvides = new LinkedHashMap<>();
 806         for (ProvidesDirective p : m.provides) {
 807             mergedProvides.computeIfAbsent(p.service, s -> new LinkedHashSet<>()).addAll(p.impls);
 808         }
 809         databuf.appendChar(mergedProvides.size());
 810         mergedProvides.forEach((srvc, impls) -> {
 811             databuf.appendChar(poolWriter.putClass(srvc));
 812             databuf.appendChar(impls.size());
 813             impls.forEach(impl -> databuf.appendChar(poolWriter.putClass(impl)));
 814         });
 815 
 816         endAttr(alenIdx);
 817         return 1;
 818     }
 819 
 820 /**********************************************************************
 821  * Writing Objects
 822  **********************************************************************/
 823 
 824     /** Write "inner classes" attribute.
 825      */
 826     void writeInnerClasses() {
 827         int alenIdx = writeAttr(names.InnerClasses);
 828         databuf.appendChar(poolWriter.innerClasses.size());
 829         for (ClassSymbol inner : poolWriter.innerClasses) {
 830             inner.markAbstractIfNeeded(types);
 831             int flags = adjustFlags(inner.flags_field);
 832             if ((flags & INTERFACE) != 0) flags |= ABSTRACT; // Interfaces are always ABSTRACT
 833             if (dumpInnerClassModifiers) {
 834                 PrintWriter pw = log.getWriter(Log.WriterKind.ERROR);
 835                 pw.println("INNERCLASS  " + inner.name);
 836                 pw.println("---" + flagNames(flags));
 837             }
 838             databuf.appendChar(poolWriter.putClass(inner));
 839             databuf.appendChar(
 840                 inner.owner.kind == TYP && !inner.name.isEmpty() ? poolWriter.putClass((ClassSymbol)inner.owner) : 0);
 841             databuf.appendChar(
 842                 !inner.name.isEmpty() ? poolWriter.putName(inner.name) : 0);
 843             databuf.appendChar(flags);
 844         }
 845         endAttr(alenIdx);
 846     }
 847 
 848      /** Write out "Preload" attribute by enumerating the value classes encountered in field/method descriptors during this compilation.
 849       */
 850      void writePreloadAttribute() {
 851         int alenIdx = writeAttr(names.Preload);
 852         databuf.appendChar(poolWriter.preloadClasses.size());
 853         for (ClassSymbol c : poolWriter.preloadClasses) {
 854             databuf.appendChar(poolWriter.putClass(c));
 855         }
 856         endAttr(alenIdx);
 857      }
 858 
 859     int writeRecordAttribute(ClassSymbol csym) {
 860         int alenIdx = writeAttr(names.Record);
 861         Scope s = csym.members();
 862         databuf.appendChar(csym.getRecordComponents().size());
 863         for (VarSymbol v: csym.getRecordComponents()) {
 864             //databuf.appendChar(poolWriter.putMember(v.accessor.head.snd));
 865             databuf.appendChar(poolWriter.putName(v.name));
 866             databuf.appendChar(poolWriter.putDescriptor(v));
 867             int acountIdx = beginAttrs();
 868             int acount = 0;
 869             acount += writeMemberAttrs(v, true);
 870             endAttrs(acountIdx, acount);
 871         }
 872         endAttr(alenIdx);
 873         return 1;
 874     }
 875 
 876     /**
 877      * Write NestMembers attribute (if needed)
 878      */
 879     int writeNestMembersIfNeeded(ClassSymbol csym) {
 880         ListBuffer<ClassSymbol> nested = new ListBuffer<>();
 881         listNested(csym, nested);
 882         Set<ClassSymbol> nestedUnique = new LinkedHashSet<>(nested);
 883         if (csym.owner.kind == PCK && !nestedUnique.isEmpty()) {
 884             int alenIdx = writeAttr(names.NestMembers);
 885             databuf.appendChar(nestedUnique.size());
 886             for (ClassSymbol s : nestedUnique) {
 887                 databuf.appendChar(poolWriter.putClass(s));
 888             }
 889             endAttr(alenIdx);
 890             return 1;
 891         }
 892         return 0;
 893     }
 894 
 895     /**
 896      * Write NestHost attribute (if needed)
 897      */
 898     int writeNestHostIfNeeded(ClassSymbol csym) {
 899         if (csym.owner.kind != PCK) {
 900             int alenIdx = writeAttr(names.NestHost);
 901             databuf.appendChar(poolWriter.putClass(csym.outermostClass()));
 902             endAttr(alenIdx);
 903             return 1;
 904         }
 905         return 0;
 906     }
 907 
 908     private void listNested(Symbol sym, ListBuffer<ClassSymbol> seen) {
 909         if (sym.kind != TYP) return;
 910         ClassSymbol csym = (ClassSymbol)sym;
 911         if (csym.owner.kind != PCK) {
 912             seen.add(csym);
 913         }
 914         if (csym.members() != null) {
 915             for (Symbol s : sym.members().getSymbols()) {
 916                 listNested(s, seen);
 917             }
 918         }
 919         if (csym.trans_local != null) {
 920             for (Symbol s : csym.trans_local) {
 921                 listNested(s, seen);
 922             }
 923         }
 924     }
 925 
 926     /** Write "PermittedSubclasses" attribute.
 927      */
 928     int writePermittedSubclassesIfNeeded(ClassSymbol csym) {
 929         if (csym.permitted.nonEmpty()) {
 930             int alenIdx = writeAttr(names.PermittedSubclasses);
 931             databuf.appendChar(csym.permitted.size());
 932             for (Symbol c : csym.permitted) {
 933                 databuf.appendChar(poolWriter.putClass((ClassSymbol) c));
 934             }
 935             endAttr(alenIdx);
 936             return 1;
 937         }
 938         return 0;
 939     }
 940 
 941     /** Write "bootstrapMethods" attribute.
 942      */
 943     void writeBootstrapMethods() {
 944         int alenIdx = writeAttr(names.BootstrapMethods);
 945         databuf.appendChar(poolWriter.bootstrapMethods.size());
 946         for (BsmKey bsmKey : poolWriter.bootstrapMethods.keySet()) {
 947             //write BSM handle
 948             databuf.appendChar(poolWriter.putConstant(bsmKey.bsm));
 949             LoadableConstant[] uniqueArgs = bsmKey.staticArgs;
 950             //write static args length
 951             databuf.appendChar(uniqueArgs.length);
 952             //write static args array
 953             for (LoadableConstant arg : uniqueArgs) {
 954                 databuf.appendChar(poolWriter.putConstant(arg));
 955             }
 956         }
 957         endAttr(alenIdx);
 958     }
 959 
 960     /** Write field symbol, entering all references into constant pool.
 961      */
 962     void writeField(VarSymbol v) {
 963         int flags = adjustFlags(v.flags());
 964         databuf.appendChar(flags);
 965         if (dumpFieldModifiers) {
 966             PrintWriter pw = log.getWriter(Log.WriterKind.ERROR);
 967             pw.println("FIELD  " + v.name);
 968             pw.println("---" + flagNames(v.flags()));
 969         }
 970         databuf.appendChar(poolWriter.putName(v.name));
 971         databuf.appendChar(poolWriter.putDescriptor(v));
 972         Type fldType = v.erasure(types);
 973         if (fldType.requiresPreload(v.owner)) {
 974             poolWriter.enterPreloadClass((ClassSymbol) fldType.tsym);
 975         }
 976         int acountIdx = beginAttrs();
 977         int acount = 0;
 978         if (v.getConstValue() != null) {
 979             int alenIdx = writeAttr(names.ConstantValue);
 980             databuf.appendChar(poolWriter.putConstant(v.getConstValue()));
 981             endAttr(alenIdx);
 982             acount++;
 983         }
 984         acount += writeMemberAttrs(v, false);
 985         acount += writeExtraAttributes(v);
 986         endAttrs(acountIdx, acount);
 987     }
 988 
 989     /** Write method symbol, entering all references into constant pool.
 990      */
 991     void writeMethod(MethodSymbol m) {
 992         int flags = adjustFlags(m.flags());
 993         databuf.appendChar(flags);
 994         if (dumpMethodModifiers) {
 995             PrintWriter pw = log.getWriter(Log.WriterKind.ERROR);
 996             pw.println("METHOD  " + m.name);
 997             pw.println("---" + flagNames(m.flags()));
 998         }
 999         databuf.appendChar(poolWriter.putName(m.name));
1000         databuf.appendChar(poolWriter.putDescriptor(m));
1001         MethodType mtype = (MethodType) m.externalType(types);
1002         for (Type t : mtype.getParameterTypes()) {
1003             if (t.requiresPreload(m.owner)) {
1004                 poolWriter.enterPreloadClass((ClassSymbol) t.tsym);
1005             }
1006         }
1007         Type returnType = mtype.getReturnType();
1008         if (returnType.requiresPreload(m.owner)) {
1009             poolWriter.enterPreloadClass((ClassSymbol) returnType.tsym);
1010         }
1011         int acountIdx = beginAttrs();
1012         int acount = 0;
1013         if (m.code != null) {
1014             int alenIdx = writeAttr(names.Code);
1015             writeCode(m.code);
1016             m.code = null; // to conserve space
1017             endAttr(alenIdx);
1018             acount++;
1019         }
1020         List<Type> thrown = m.erasure(types).getThrownTypes();
1021         if (thrown.nonEmpty()) {
1022             int alenIdx = writeAttr(names.Exceptions);
1023             databuf.appendChar(thrown.length());
1024             for (List<Type> l = thrown; l.nonEmpty(); l = l.tail)
1025                 databuf.appendChar(poolWriter.putClass(l.head));
1026             endAttr(alenIdx);
1027             acount++;
1028         }
1029         if (m.defaultValue != null) {
1030             int alenIdx = writeAttr(names.AnnotationDefault);
1031             m.defaultValue.accept(awriter);
1032             endAttr(alenIdx);
1033             acount++;
1034         }
1035         if (target.hasMethodParameters() && (
1036                 options.isSet(PARAMETERS)
1037                 || ((m.flags_field & RECORD) != 0 && (m.isConstructor() || m.isValueObjectFactory())))) {
1038             if (!m.isLambdaMethod()) // Per JDK-8138729, do not emit parameters table for lambda bodies.
1039                 acount += writeMethodParametersAttr(m);
1040         }
1041         acount += writeMemberAttrs(m, false);
1042         if (!m.isLambdaMethod())
1043             acount += writeParameterAttrs(m.params);
1044         acount += writeExtraAttributes(m);
1045         endAttrs(acountIdx, acount);
1046     }
1047 
1048     /** Write code attribute of method.
1049      */
1050     void writeCode(Code code) {
1051         databuf.appendChar(code.max_stack);
1052         databuf.appendChar(code.max_locals);
1053         databuf.appendInt(code.cp);
1054         databuf.appendBytes(code.code, 0, code.cp);
1055         databuf.appendChar(code.catchInfo.length());
1056         for (List<char[]> l = code.catchInfo.toList();
1057              l.nonEmpty();
1058              l = l.tail) {
1059             for (int i = 0; i < l.head.length; i++)
1060                 databuf.appendChar(l.head[i]);
1061         }
1062         int acountIdx = beginAttrs();
1063         int acount = 0;
1064 
1065         if (code.lineInfo.nonEmpty()) {
1066             int alenIdx = writeAttr(names.LineNumberTable);
1067             databuf.appendChar(code.lineInfo.length());
1068             for (List<char[]> l = code.lineInfo.reverse();
1069                  l.nonEmpty();
1070                  l = l.tail)
1071                 for (int i = 0; i < l.head.length; i++)
1072                     databuf.appendChar(l.head[i]);
1073             endAttr(alenIdx);
1074             acount++;
1075         }
1076 
1077         if (genCrt && (code.crt != null)) {
1078             CRTable crt = code.crt;
1079             int alenIdx = writeAttr(names.CharacterRangeTable);
1080             int crtIdx = beginAttrs();
1081             int crtEntries = crt.writeCRT(databuf, code.lineMap, log);
1082             endAttrs(crtIdx, crtEntries);
1083             endAttr(alenIdx);
1084             acount++;
1085         }
1086 
1087         // counter for number of generic local variables
1088         if (code.varDebugInfo && code.varBufferSize > 0) {
1089             int nGenericVars = 0;
1090             int alenIdx = writeAttr(names.LocalVariableTable);
1091             databuf.appendChar(code.getLVTSize());
1092             for (int i=0; i<code.varBufferSize; i++) {
1093                 Code.LocalVar var = code.varBuffer[i];
1094 
1095                 for (Code.LocalVar.Range r: var.aliveRanges) {
1096                     // write variable info
1097                     Assert.check(r.start_pc >= 0
1098                             && r.start_pc <= code.cp);
1099                     databuf.appendChar(r.start_pc);
1100                     Assert.check(r.length > 0
1101                             && (r.start_pc + r.length) <= code.cp);
1102                     databuf.appendChar(r.length);
1103                     VarSymbol sym = var.sym;
1104                     databuf.appendChar(poolWriter.putName(sym.name));
1105                     databuf.appendChar(poolWriter.putDescriptor(sym));
1106                     databuf.appendChar(var.reg);
1107                     if (needsLocalVariableTypeEntry(var.sym.type)) {
1108                         nGenericVars++;
1109                     }
1110                 }
1111             }
1112             endAttr(alenIdx);
1113             acount++;
1114 
1115             if (nGenericVars > 0) {
1116                 alenIdx = writeAttr(names.LocalVariableTypeTable);
1117                 databuf.appendChar(nGenericVars);
1118                 int count = 0;
1119 
1120                 for (int i=0; i<code.varBufferSize; i++) {
1121                     Code.LocalVar var = code.varBuffer[i];
1122                     VarSymbol sym = var.sym;
1123                     if (!needsLocalVariableTypeEntry(sym.type))
1124                         continue;
1125                     for (Code.LocalVar.Range r : var.aliveRanges) {
1126                         // write variable info
1127                         databuf.appendChar(r.start_pc);
1128                         databuf.appendChar(r.length);
1129                         databuf.appendChar(poolWriter.putName(sym.name));
1130                         databuf.appendChar(poolWriter.putSignature(sym));
1131                         databuf.appendChar(var.reg);
1132                         count++;
1133                     }
1134                 }
1135                 Assert.check(count == nGenericVars);
1136                 endAttr(alenIdx);
1137                 acount++;
1138             }
1139         }
1140 
1141         if (code.stackMapBufferSize > 0) {
1142             if (debugstackmap) System.out.println("Stack map for " + code.meth);
1143             int alenIdx = writeAttr(code.stackMap.getAttributeName(names));
1144             writeStackMap(code);
1145             endAttr(alenIdx);
1146             acount++;
1147         }
1148 
1149         acount += writeTypeAnnotations(code.meth.getRawTypeAttributes(), true);
1150 
1151         endAttrs(acountIdx, acount);
1152     }
1153     //where
1154     private boolean needsLocalVariableTypeEntry(Type t) {
1155         //a local variable needs a type-entry if its type T is generic
1156         //(i.e. |T| != T) and if it's not an non-denotable type (non-denotable
1157         // types are not supported in signature attribute grammar!)
1158         return !types.isSameType(t, types.erasure(t)) &&
1159                 check.checkDenotable(t);
1160     }
1161 
1162     void writeStackMap(Code code) {
1163         int nframes = code.stackMapBufferSize;
1164         if (debugstackmap) System.out.println(" nframes = " + nframes);
1165         databuf.appendChar(nframes);
1166 
1167         switch (code.stackMap) {
1168         case CLDC:
1169             for (int i=0; i<nframes; i++) {
1170                 if (debugstackmap) System.out.print("  " + i + ":");
1171                 Code.StackMapFrame frame = code.stackMapBuffer[i];
1172 
1173                 // output PC
1174                 if (debugstackmap) System.out.print(" pc=" + frame.pc);
1175                 databuf.appendChar(frame.pc);
1176 
1177                 // output locals
1178                 int localCount = 0;
1179                 for (int j=0; j<frame.locals.length;
1180                      j += Code.width(frame.locals[j])) {
1181                     localCount++;
1182                 }
1183                 if (debugstackmap) System.out.print(" nlocals=" +
1184                                                     localCount);
1185                 databuf.appendChar(localCount);
1186                 for (int j=0; j<frame.locals.length;
1187                      j += Code.width(frame.locals[j])) {
1188                     if (debugstackmap) System.out.print(" local[" + j + "]=");
1189                     writeStackMapType(frame.locals[j]);
1190                 }
1191 
1192                 // output stack
1193                 int stackCount = 0;
1194                 for (int j=0; j<frame.stack.length;
1195                      j += Code.width(frame.stack[j])) {
1196                     stackCount++;
1197                 }
1198                 if (debugstackmap) System.out.print(" nstack=" +
1199                                                     stackCount);
1200                 databuf.appendChar(stackCount);
1201                 for (int j=0; j<frame.stack.length;
1202                      j += Code.width(frame.stack[j])) {
1203                     if (debugstackmap) System.out.print(" stack[" + j + "]=");
1204                     writeStackMapType(frame.stack[j]);
1205                 }
1206                 if (debugstackmap) System.out.println();
1207             }
1208             break;
1209         case JSR202: {
1210             Assert.checkNull(code.stackMapBuffer);
1211             for (int i=0; i<nframes; i++) {
1212                 if (debugstackmap) System.out.print("  " + i + ":");
1213                 StackMapTableFrame frame = code.stackMapTableBuffer[i];
1214                 frame.write(this);
1215                 if (debugstackmap) System.out.println();
1216             }
1217             break;
1218         }
1219         default:
1220             throw new AssertionError("Unexpected stackmap format value");
1221         }
1222     }
1223 
1224         //where
1225         void writeStackMapType(Type t) {
1226             if (t == null) {
1227                 if (debugstackmap) System.out.print("empty");
1228                 databuf.appendByte(0);
1229             }
1230             else switch(t.getTag()) {
1231             case BYTE:
1232             case CHAR:
1233             case SHORT:
1234             case INT:
1235             case BOOLEAN:
1236                 if (debugstackmap) System.out.print("int");
1237                 databuf.appendByte(1);
1238                 break;
1239             case FLOAT:
1240                 if (debugstackmap) System.out.print("float");
1241                 databuf.appendByte(2);
1242                 break;
1243             case DOUBLE:
1244                 if (debugstackmap) System.out.print("double");
1245                 databuf.appendByte(3);
1246                 break;
1247             case LONG:
1248                 if (debugstackmap) System.out.print("long");
1249                 databuf.appendByte(4);
1250                 break;
1251             case BOT: // null
1252                 if (debugstackmap) System.out.print("null");
1253                 databuf.appendByte(5);
1254                 break;
1255             case CLASS:
1256             case ARRAY:
1257                 if (debugstackmap) System.out.print("object(" + types.erasure(t).tsym + ")");
1258                 databuf.appendByte(7);
1259                 databuf.appendChar(t.isPrimitiveClass() ? poolWriter.putClass(new ConstantPoolQType(types.erasure(t), types)) : poolWriter.putClass(types.erasure(t)));
1260                 break;
1261             case TYPEVAR:
1262                 if (debugstackmap) System.out.print("object(" + types.erasure(t).tsym + ")");
1263                 databuf.appendByte(7);
1264                 databuf.appendChar(poolWriter.putClass(types.erasure(t)));
1265                 break;
1266             case UNINITIALIZED_THIS:
1267                 if (debugstackmap) System.out.print("uninit_this");
1268                 databuf.appendByte(6);
1269                 break;
1270             case UNINITIALIZED_OBJECT:
1271                 { UninitializedType uninitType = (UninitializedType)t;
1272                 databuf.appendByte(8);
1273                 if (debugstackmap) System.out.print("uninit_object@" + uninitType.offset);
1274                 databuf.appendChar(uninitType.offset);
1275                 }
1276                 break;
1277             default:
1278                 throw new AssertionError();
1279             }
1280         }
1281 
1282     /** An entry in the JSR202 StackMapTable */
1283     abstract static class StackMapTableFrame {
1284         abstract int getFrameType();
1285 
1286         void write(ClassWriter writer) {
1287             int frameType = getFrameType();
1288             writer.databuf.appendByte(frameType);
1289             if (writer.debugstackmap) System.out.print(" frame_type=" + frameType);
1290         }
1291 
1292         static class SameFrame extends StackMapTableFrame {
1293             final int offsetDelta;
1294             SameFrame(int offsetDelta) {
1295                 this.offsetDelta = offsetDelta;
1296             }
1297             int getFrameType() {
1298                 return (offsetDelta < SAME_FRAME_SIZE) ? offsetDelta : SAME_FRAME_EXTENDED;
1299             }
1300             @Override
1301             void write(ClassWriter writer) {
1302                 super.write(writer);
1303                 if (getFrameType() == SAME_FRAME_EXTENDED) {
1304                     writer.databuf.appendChar(offsetDelta);
1305                     if (writer.debugstackmap){
1306                         System.out.print(" offset_delta=" + offsetDelta);
1307                     }
1308                 }
1309             }
1310         }
1311 
1312         static class SameLocals1StackItemFrame extends StackMapTableFrame {
1313             final int offsetDelta;
1314             final Type stack;
1315             SameLocals1StackItemFrame(int offsetDelta, Type stack) {
1316                 this.offsetDelta = offsetDelta;
1317                 this.stack = stack;
1318             }
1319             int getFrameType() {
1320                 return (offsetDelta < SAME_FRAME_SIZE) ?
1321                        (SAME_FRAME_SIZE + offsetDelta) :
1322                        SAME_LOCALS_1_STACK_ITEM_EXTENDED;
1323             }
1324             @Override
1325             void write(ClassWriter writer) {
1326                 super.write(writer);
1327                 if (getFrameType() == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
1328                     writer.databuf.appendChar(offsetDelta);
1329                     if (writer.debugstackmap) {
1330                         System.out.print(" offset_delta=" + offsetDelta);
1331                     }
1332                 }
1333                 if (writer.debugstackmap) {
1334                     System.out.print(" stack[" + 0 + "]=");
1335                 }
1336                 writer.writeStackMapType(stack);
1337             }
1338         }
1339 
1340         static class ChopFrame extends StackMapTableFrame {
1341             final int frameType;
1342             final int offsetDelta;
1343             ChopFrame(int frameType, int offsetDelta) {
1344                 this.frameType = frameType;
1345                 this.offsetDelta = offsetDelta;
1346             }
1347             int getFrameType() { return frameType; }
1348             @Override
1349             void write(ClassWriter writer) {
1350                 super.write(writer);
1351                 writer.databuf.appendChar(offsetDelta);
1352                 if (writer.debugstackmap) {
1353                     System.out.print(" offset_delta=" + offsetDelta);
1354                 }
1355             }
1356         }
1357 
1358         static class AppendFrame extends StackMapTableFrame {
1359             final int frameType;
1360             final int offsetDelta;
1361             final Type[] locals;
1362             AppendFrame(int frameType, int offsetDelta, Type[] locals) {
1363                 this.frameType = frameType;
1364                 this.offsetDelta = offsetDelta;
1365                 this.locals = locals;
1366             }
1367             int getFrameType() { return frameType; }
1368             @Override
1369             void write(ClassWriter writer) {
1370                 super.write(writer);
1371                 writer.databuf.appendChar(offsetDelta);
1372                 if (writer.debugstackmap) {
1373                     System.out.print(" offset_delta=" + offsetDelta);
1374                 }
1375                 for (int i=0; i<locals.length; i++) {
1376                      if (writer.debugstackmap) System.out.print(" locals[" + i + "]=");
1377                      writer.writeStackMapType(locals[i]);
1378                 }
1379             }
1380         }
1381 
1382         static class FullFrame extends StackMapTableFrame {
1383             final int offsetDelta;
1384             final Type[] locals;
1385             final Type[] stack;
1386             FullFrame(int offsetDelta, Type[] locals, Type[] stack) {
1387                 this.offsetDelta = offsetDelta;
1388                 this.locals = locals;
1389                 this.stack = stack;
1390             }
1391             int getFrameType() { return FULL_FRAME; }
1392             @Override
1393             void write(ClassWriter writer) {
1394                 super.write(writer);
1395                 writer.databuf.appendChar(offsetDelta);
1396                 writer.databuf.appendChar(locals.length);
1397                 if (writer.debugstackmap) {
1398                     System.out.print(" offset_delta=" + offsetDelta);
1399                     System.out.print(" nlocals=" + locals.length);
1400                 }
1401                 for (int i=0; i<locals.length; i++) {
1402                     if (writer.debugstackmap) System.out.print(" locals[" + i + "]=");
1403                     writer.writeStackMapType(locals[i]);
1404                 }
1405 
1406                 writer.databuf.appendChar(stack.length);
1407                 if (writer.debugstackmap) { System.out.print(" nstack=" + stack.length); }
1408                 for (int i=0; i<stack.length; i++) {
1409                     if (writer.debugstackmap) System.out.print(" stack[" + i + "]=");
1410                     writer.writeStackMapType(stack[i]);
1411                 }
1412             }
1413         }
1414 
1415        /** Compare this frame with the previous frame and produce
1416         *  an entry of compressed stack map frame. */
1417         static StackMapTableFrame getInstance(Code.StackMapFrame this_frame,
1418                                               int prev_pc,
1419                                               Type[] prev_locals,
1420                                               Types types) {
1421             Type[] locals = this_frame.locals;
1422             Type[] stack = this_frame.stack;
1423             int offset_delta = this_frame.pc - prev_pc - 1;
1424             if (stack.length == 1) {
1425                 if (locals.length == prev_locals.length
1426                     && compare(prev_locals, locals, types) == 0) {
1427                     return new SameLocals1StackItemFrame(offset_delta, stack[0]);
1428                 }
1429             } else if (stack.length == 0) {
1430                 int diff_length = compare(prev_locals, locals, types);
1431                 if (diff_length == 0) {
1432                     return new SameFrame(offset_delta);
1433                 } else if (-MAX_LOCAL_LENGTH_DIFF < diff_length && diff_length < 0) {
1434                     // APPEND
1435                     Type[] local_diff = new Type[-diff_length];
1436                     for (int i=prev_locals.length, j=0; i<locals.length; i++,j++) {
1437                         local_diff[j] = locals[i];
1438                     }
1439                     return new AppendFrame(SAME_FRAME_EXTENDED - diff_length,
1440                                            offset_delta,
1441                                            local_diff);
1442                 } else if (0 < diff_length && diff_length < MAX_LOCAL_LENGTH_DIFF) {
1443                     // CHOP
1444                     return new ChopFrame(SAME_FRAME_EXTENDED - diff_length,
1445                                          offset_delta);
1446                 }
1447             }
1448             // FULL_FRAME
1449             return new FullFrame(offset_delta, locals, stack);
1450         }
1451 
1452         static boolean isInt(Type t) {
1453             return (t.getTag().isStrictSubRangeOf(INT)  || t.hasTag(BOOLEAN));
1454         }
1455 
1456         static boolean isSameType(Type t1, Type t2, Types types) {
1457             if (t1 == null) { return t2 == null; }
1458             if (t2 == null) { return false; }
1459 
1460             if (isInt(t1) && isInt(t2)) { return true; }
1461 
1462             if (t1.hasTag(UNINITIALIZED_THIS)) {
1463                 return t2.hasTag(UNINITIALIZED_THIS);
1464             } else if (t1.hasTag(UNINITIALIZED_OBJECT)) {
1465                 if (t2.hasTag(UNINITIALIZED_OBJECT)) {
1466                     return ((UninitializedType)t1).offset == ((UninitializedType)t2).offset;
1467                 } else {
1468                     return false;
1469                 }
1470             } else if (t2.hasTag(UNINITIALIZED_THIS) || t2.hasTag(UNINITIALIZED_OBJECT)) {
1471                 return false;
1472             }
1473 
1474             return types.isSameType(t1, t2);
1475         }
1476 
1477         static int compare(Type[] arr1, Type[] arr2, Types types) {
1478             int diff_length = arr1.length - arr2.length;
1479             if (diff_length > MAX_LOCAL_LENGTH_DIFF || diff_length < -MAX_LOCAL_LENGTH_DIFF) {
1480                 return Integer.MAX_VALUE;
1481             }
1482             int len = (diff_length > 0) ? arr2.length : arr1.length;
1483             for (int i=0; i<len; i++) {
1484                 if (!isSameType(arr1[i], arr2[i], types)) {
1485                     return Integer.MAX_VALUE;
1486                 }
1487             }
1488             return diff_length;
1489         }
1490     }
1491 
1492     void writeFields(Scope s) {
1493         // process them in reverse sibling order;
1494         // i.e., process them in declaration order.
1495         List<VarSymbol> vars = List.nil();
1496         for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
1497             if (sym.kind == VAR) vars = vars.prepend((VarSymbol)sym);
1498         }
1499         while (vars.nonEmpty()) {
1500             writeField(vars.head);
1501             vars = vars.tail;
1502         }
1503     }
1504 
1505     void writeMethods(Scope s) {
1506         List<MethodSymbol> methods = List.nil();
1507         for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
1508             if (sym.kind == MTH && (sym.flags() & HYPOTHETICAL) == 0)
1509                 methods = methods.prepend((MethodSymbol)sym);
1510         }
1511         while (methods.nonEmpty()) {
1512             writeMethod(methods.head);
1513             methods = methods.tail;
1514         }
1515     }
1516 
1517     /** Emit a class file for a given class.
1518      *  @param c      The class from which a class file is generated.
1519      */
1520     public JavaFileObject writeClass(ClassSymbol c)
1521         throws IOException, PoolOverflow, StringOverflow
1522     {
1523         String name = (c.owner.kind == MDL ? c.name : c.flatname).toString();
1524         Location outLocn;
1525         if (multiModuleMode) {
1526             ModuleSymbol msym = c.owner.kind == MDL ? (ModuleSymbol) c.owner : c.packge().modle;
1527             outLocn = fileManager.getLocationForModule(CLASS_OUTPUT, msym.name.toString());
1528         } else {
1529             outLocn = CLASS_OUTPUT;
1530         }
1531         JavaFileObject outFile
1532             = fileManager.getJavaFileForOutput(outLocn,
1533                                                name,
1534                                                JavaFileObject.Kind.CLASS,
1535                                                c.sourcefile);
1536         OutputStream out = outFile.openOutputStream();
1537         try {
1538             writeClassFile(out, c);
1539             if (verbose)
1540                 log.printVerbose("wrote.file", outFile.getName());
1541             out.close();
1542             out = null;
1543         } catch (InvalidSignatureException ex) {
1544             log.error(Errors.CannotGenerateClass(c, Fragments.IllegalSignature(c, ex.type())));
1545         } finally {
1546             if (out != null) {
1547                 // if we are propagating an exception, delete the file
1548                 out.close();
1549                 outFile.delete();
1550                 outFile = null;
1551             }
1552         }
1553         return outFile; // may be null if write failed
1554     }
1555 
1556     /** Write class `c' to outstream `out'.
1557      */
1558     public void writeClassFile(OutputStream out, ClassSymbol c)
1559         throws IOException, PoolOverflow, StringOverflow {
1560         Assert.check((c.flags() & COMPOUND) == 0);
1561         databuf.reset();
1562         poolbuf.reset();
1563 
1564         Type supertype = types.supertype(c.type);
1565         List<Type> interfaces = types.interfaces(c.type);
1566         List<Type> typarams = c.type.getTypeArguments();
1567 
1568         int flags;
1569         if (c.owner.kind == MDL) {
1570             flags = ACC_MODULE;
1571         } else {
1572             flags = adjustFlags(c.flags() & ~(DEFAULT | STRICTFP));
1573             if ((flags & PROTECTED) != 0) flags |= PUBLIC;
1574             flags = flags & AdjustedClassFlags;
1575         }
1576 
1577         if (dumpClassModifiers) {
1578             PrintWriter pw = log.getWriter(Log.WriterKind.ERROR);
1579             pw.println();
1580             pw.println("CLASSFILE  " + c.getQualifiedName());
1581             pw.println("---" + flagNames(flags));
1582         }
1583         databuf.appendChar(flags);
1584 
1585         if (c.owner.kind == MDL) {
1586             PackageSymbol unnamed = ((ModuleSymbol) c.owner).unnamedPackage;
1587             databuf.appendChar(poolWriter.putClass(new ClassSymbol(0, names.module_info, unnamed)));
1588         } else {
1589             databuf.appendChar(poolWriter.putClass(c));
1590         }
1591         databuf.appendChar(supertype.hasTag(CLASS) ? poolWriter.putClass((ClassSymbol)supertype.tsym) : 0);
1592         databuf.appendChar(interfaces.length());
1593         for (List<Type> l = interfaces; l.nonEmpty(); l = l.tail)
1594             databuf.appendChar(poolWriter.putClass((ClassSymbol)l.head.tsym));
1595         int fieldsCount = 0;
1596         int methodsCount = 0;
1597         for (Symbol sym : c.members().getSymbols(NON_RECURSIVE)) {
1598             switch (sym.kind) {
1599             case VAR: fieldsCount++; break;
1600             case MTH: if ((sym.flags() & HYPOTHETICAL) == 0) methodsCount++;
1601                       break;
1602             case TYP: poolWriter.enterInnerClass((ClassSymbol)sym); break;
1603             default : Assert.error();
1604             }
1605         }
1606 
1607         if (c.trans_local != null) {
1608             for (ClassSymbol local : c.trans_local) {
1609                 poolWriter.enterInnerClass(local);
1610             }
1611         }
1612 
1613         databuf.appendChar(fieldsCount);
1614         writeFields(c.members());
1615         databuf.appendChar(methodsCount);
1616         writeMethods(c.members());
1617 
1618         int acountIdx = beginAttrs();
1619         int acount = 0;
1620 
1621         boolean sigReq =
1622             typarams.length() != 0 || supertype.allparams().length() != 0;
1623         for (List<Type> l = interfaces; !sigReq && l.nonEmpty(); l = l.tail)
1624             sigReq = l.head.allparams().length() != 0;
1625         if (sigReq) {
1626             int alenIdx = writeAttr(names.Signature);
1627             databuf.appendChar(poolWriter.putSignature(c));
1628             endAttr(alenIdx);
1629             acount++;
1630         }
1631 
1632         if (c.sourcefile != null && emitSourceFile) {
1633             int alenIdx = writeAttr(names.SourceFile);
1634             // WHM 6/29/1999: Strip file path prefix.  We do it here at
1635             // the last possible moment because the sourcefile may be used
1636             // elsewhere in error diagnostics. Fixes 4241573.
1637             String simpleName = PathFileObject.getSimpleName(c.sourcefile);
1638             databuf.appendChar(poolWriter.putName(names.fromString(simpleName)));
1639             endAttr(alenIdx);
1640             acount++;
1641         }
1642 
1643         if (genCrt) {
1644             // Append SourceID attribute
1645             int alenIdx = writeAttr(names.SourceID);
1646             databuf.appendChar(poolWriter.putName(names.fromString(Long.toString(getLastModified(c.sourcefile)))));
1647             endAttr(alenIdx);
1648             acount++;
1649             // Append CompilationID attribute
1650             alenIdx = writeAttr(names.CompilationID);
1651             databuf.appendChar(poolWriter.putName(names.fromString(Long.toString(System.currentTimeMillis()))));
1652             endAttr(alenIdx);
1653             acount++;
1654         }
1655 
1656         acount += writeFlagAttrs(c.flags());
1657         acount += writeJavaAnnotations(c.getRawAttributes());
1658         acount += writeTypeAnnotations(c.getRawTypeAttributes(), false);
1659         acount += writeEnclosingMethodAttribute(c);
1660         if (c.owner.kind == MDL) {
1661             acount += writeModuleAttribute(c);
1662             acount += writeFlagAttrs(c.owner.flags() & ~DEPRECATED);
1663         }
1664         acount += writeExtraClassAttributes(c);
1665         acount += writeExtraAttributes(c);
1666 
1667         poolbuf.appendInt(JAVA_MAGIC);
1668         if (preview.isEnabled() && preview.usesPreview(c.sourcefile)) {
1669             poolbuf.appendChar(ClassFile.PREVIEW_MINOR_VERSION);
1670         } else {
1671             poolbuf.appendChar(target.minorVersion);
1672         }
1673         poolbuf.appendChar(target.majorVersion);
1674 
1675         if (c.owner.kind != MDL) {
1676             if (target.hasNestmateAccess()) {
1677                 acount += writeNestMembersIfNeeded(c);
1678                 acount += writeNestHostIfNeeded(c);
1679             }
1680         }
1681 
1682         if (c.isRecord()) {
1683             acount += writeRecordAttribute(c);
1684         }
1685 
1686         if (target.hasSealedClasses()) {
1687             acount += writePermittedSubclassesIfNeeded(c);
1688         }
1689 
1690         if (!poolWriter.bootstrapMethods.isEmpty()) {
1691             writeBootstrapMethods();
1692             acount++;
1693         }
1694 
1695         if (!poolWriter.innerClasses.isEmpty()) {
1696             writeInnerClasses();
1697             acount++;
1698         }
1699 
1700         if (!poolWriter.preloadClasses.isEmpty()) {
1701             writePreloadAttribute();
1702             acount++;
1703         }
1704 
1705         endAttrs(acountIdx, acount);
1706 
1707         out.write(poolbuf.elems, 0, poolbuf.length);
1708 
1709         poolWriter.writePool(out);
1710         poolWriter.reset(); // to save space
1711 
1712         out.write(databuf.elems, 0, databuf.length);
1713     }
1714 
1715      /**Allows subclasses to write additional class attributes
1716       *
1717       * @return the number of attributes written
1718       */
1719     protected int writeExtraClassAttributes(ClassSymbol c) {
1720         return 0;
1721     }
1722 
1723     /**Allows friends to write additional attributes
1724      *
1725      * @return the number of attributes written
1726      */
1727     protected int writeExtraAttributes(Symbol sym) {
1728         int i = 0;
1729         for (ToIntFunction<Symbol> hook : extraAttributeHooks) {
1730             i += hook.applyAsInt(sym);
1731         }
1732         return i;
1733     }
1734 
1735     int adjustFlags(final long flags) {
1736         int result = (int)flags;
1737 
1738         // Elide strictfp bit in class files
1739         if (target.obsoleteAccStrict())
1740             result &= ~STRICTFP;
1741 
1742         if ((flags & BRIDGE) != 0)
1743             result |= ACC_BRIDGE;
1744         if ((flags & VARARGS) != 0)
1745             result |= ACC_VARARGS;
1746         if ((flags & DEFAULT) != 0)
1747             result &= ~ABSTRACT;
1748         if ((flags & PRIMITIVE_CLASS) != 0)
1749             result |= ACC_PRIMITIVE;
1750         if ((flags & VALUE_CLASS) != 0)
1751             result |= ACC_VALUE;
1752         if ((flags & IDENTITY_TYPE) != 0)
1753             result |= ACC_IDENTITY;
1754         return result;
1755     }
1756 
1757     long getLastModified(FileObject filename) {
1758         long mod = 0;
1759         try {
1760             mod = filename.getLastModified();
1761         } catch (SecurityException e) {
1762             throw new AssertionError("CRT: couldn't get source file modification date: " + e.getMessage());
1763         }
1764         return mod;
1765     }
1766 }