src/share/classes/com/sun/tools/javac/jvm/Gen.java

Thu, 27 Jun 2013 00:37:13 -0400

author
emc
date
Thu, 27 Jun 2013 00:37:13 -0400
changeset 1860
c674b396827c
parent 1802
8fb68f73d4b1
child 1865
d137ce373c4c
permissions
-rw-r--r--

8014230: Compilation incorrectly succeeds with inner class constructor with 254 parameters
Summary: The compiler does not account fr extra parameters due to inner this parameters
Reviewed-by: jjg

     1 /*
     2  * Copyright (c) 1999, 2013, 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  */
    26 package com.sun.tools.javac.jvm;
    27 import java.util.*;
    29 import com.sun.tools.javac.util.*;
    30 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
    31 import com.sun.tools.javac.util.List;
    32 import com.sun.tools.javac.code.*;
    33 import com.sun.tools.javac.code.Attribute.TypeCompound;
    34 import com.sun.tools.javac.code.Symbol.VarSymbol;
    35 import com.sun.tools.javac.comp.*;
    36 import com.sun.tools.javac.tree.*;
    38 import com.sun.tools.javac.code.Symbol.*;
    39 import com.sun.tools.javac.code.Type.*;
    40 import com.sun.tools.javac.jvm.Code.*;
    41 import com.sun.tools.javac.jvm.Items.*;
    42 import com.sun.tools.javac.tree.EndPosTable;
    43 import com.sun.tools.javac.tree.JCTree.*;
    45 import static com.sun.tools.javac.code.Flags.*;
    46 import static com.sun.tools.javac.code.Kinds.*;
    47 import static com.sun.tools.javac.code.TypeTag.*;
    48 import static com.sun.tools.javac.jvm.ByteCodes.*;
    49 import static com.sun.tools.javac.jvm.CRTFlags.*;
    50 import static com.sun.tools.javac.main.Option.*;
    51 import static com.sun.tools.javac.tree.JCTree.Tag.*;
    53 /** This pass maps flat Java (i.e. without inner classes) to bytecodes.
    54  *
    55  *  <p><b>This is NOT part of any supported API.
    56  *  If you write code that depends on this, you do so at your own risk.
    57  *  This code and its internal interfaces are subject to change or
    58  *  deletion without notice.</b>
    59  */
    60 public class Gen extends JCTree.Visitor {
    61     protected static final Context.Key<Gen> genKey =
    62         new Context.Key<Gen>();
    64     private final Log log;
    65     private final Symtab syms;
    66     private final Check chk;
    67     private final Resolve rs;
    68     private final TreeMaker make;
    69     private final Names names;
    70     private final Target target;
    71     private final Type stringBufferType;
    72     private final Map<Type,Symbol> stringBufferAppend;
    73     private Name accessDollar;
    74     private final Types types;
    75     private final Lower lower;
    77     /** Switch: GJ mode?
    78      */
    79     private final boolean allowGenerics;
    81     /** Set when Miranda method stubs are to be generated. */
    82     private final boolean generateIproxies;
    84     /** Format of stackmap tables to be generated. */
    85     private final Code.StackMapFormat stackMap;
    87     /** A type that serves as the expected type for all method expressions.
    88      */
    89     private final Type methodType;
    91     public static Gen instance(Context context) {
    92         Gen instance = context.get(genKey);
    93         if (instance == null)
    94             instance = new Gen(context);
    95         return instance;
    96     }
    98     /* Constant pool, reset by genClass.
    99      */
   100     private Pool pool;
   102     protected Gen(Context context) {
   103         context.put(genKey, this);
   105         names = Names.instance(context);
   106         log = Log.instance(context);
   107         syms = Symtab.instance(context);
   108         chk = Check.instance(context);
   109         rs = Resolve.instance(context);
   110         make = TreeMaker.instance(context);
   111         target = Target.instance(context);
   112         types = Types.instance(context);
   113         methodType = new MethodType(null, null, null, syms.methodClass);
   114         allowGenerics = Source.instance(context).allowGenerics();
   115         stringBufferType = target.useStringBuilder()
   116             ? syms.stringBuilderType
   117             : syms.stringBufferType;
   118         stringBufferAppend = new HashMap<Type,Symbol>();
   119         accessDollar = names.
   120             fromString("access" + target.syntheticNameChar());
   121         lower = Lower.instance(context);
   123         Options options = Options.instance(context);
   124         lineDebugInfo =
   125             options.isUnset(G_CUSTOM) ||
   126             options.isSet(G_CUSTOM, "lines");
   127         varDebugInfo =
   128             options.isUnset(G_CUSTOM)
   129             ? options.isSet(G)
   130             : options.isSet(G_CUSTOM, "vars");
   131         genCrt = options.isSet(XJCOV);
   132         debugCode = options.isSet("debugcode");
   133         allowInvokedynamic = target.hasInvokedynamic() || options.isSet("invokedynamic");
   134         pool = new Pool(types);
   136         generateIproxies =
   137             target.requiresIproxy() ||
   138             options.isSet("miranda");
   140         if (target.generateStackMapTable()) {
   141             // ignore cldc because we cannot have both stackmap formats
   142             this.stackMap = StackMapFormat.JSR202;
   143         } else {
   144             if (target.generateCLDCStackmap()) {
   145                 this.stackMap = StackMapFormat.CLDC;
   146             } else {
   147                 this.stackMap = StackMapFormat.NONE;
   148             }
   149         }
   151         // by default, avoid jsr's for simple finalizers
   152         int setjsrlimit = 50;
   153         String jsrlimitString = options.get("jsrlimit");
   154         if (jsrlimitString != null) {
   155             try {
   156                 setjsrlimit = Integer.parseInt(jsrlimitString);
   157             } catch (NumberFormatException ex) {
   158                 // ignore ill-formed numbers for jsrlimit
   159             }
   160         }
   161         this.jsrlimit = setjsrlimit;
   162         this.useJsrLocally = false; // reset in visitTry
   163     }
   165     /** Switches
   166      */
   167     private final boolean lineDebugInfo;
   168     private final boolean varDebugInfo;
   169     private final boolean genCrt;
   170     private final boolean debugCode;
   171     private final boolean allowInvokedynamic;
   173     /** Default limit of (approximate) size of finalizer to inline.
   174      *  Zero means always use jsr.  100 or greater means never use
   175      *  jsr.
   176      */
   177     private final int jsrlimit;
   179     /** True if jsr is used.
   180      */
   181     private boolean useJsrLocally;
   183     /** Code buffer, set by genMethod.
   184      */
   185     private Code code;
   187     /** Items structure, set by genMethod.
   188      */
   189     private Items items;
   191     /** Environment for symbol lookup, set by genClass
   192      */
   193     private Env<AttrContext> attrEnv;
   195     /** The top level tree.
   196      */
   197     private JCCompilationUnit toplevel;
   199     /** The number of code-gen errors in this class.
   200      */
   201     private int nerrs = 0;
   203     /** An object containing mappings of syntax trees to their
   204      *  ending source positions.
   205      */
   206     EndPosTable endPosTable;
   208     /** Generate code to load an integer constant.
   209      *  @param n     The integer to be loaded.
   210      */
   211     void loadIntConst(int n) {
   212         items.makeImmediateItem(syms.intType, n).load();
   213     }
   215     /** The opcode that loads a zero constant of a given type code.
   216      *  @param tc   The given type code (@see ByteCode).
   217      */
   218     public static int zero(int tc) {
   219         switch(tc) {
   220         case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
   221             return iconst_0;
   222         case LONGcode:
   223             return lconst_0;
   224         case FLOATcode:
   225             return fconst_0;
   226         case DOUBLEcode:
   227             return dconst_0;
   228         default:
   229             throw new AssertionError("zero");
   230         }
   231     }
   233     /** The opcode that loads a one constant of a given type code.
   234      *  @param tc   The given type code (@see ByteCode).
   235      */
   236     public static int one(int tc) {
   237         return zero(tc) + 1;
   238     }
   240     /** Generate code to load -1 of the given type code (either int or long).
   241      *  @param tc   The given type code (@see ByteCode).
   242      */
   243     void emitMinusOne(int tc) {
   244         if (tc == LONGcode) {
   245             items.makeImmediateItem(syms.longType, new Long(-1)).load();
   246         } else {
   247             code.emitop0(iconst_m1);
   248         }
   249     }
   251     /** Construct a symbol to reflect the qualifying type that should
   252      *  appear in the byte code as per JLS 13.1.
   253      *
   254      *  For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except
   255      *  for those cases where we need to work around VM bugs).
   256      *
   257      *  For {@literal target <= 1.1}: If qualified variable or method is defined in a
   258      *  non-accessible class, clone it with the qualifier class as owner.
   259      *
   260      *  @param sym    The accessed symbol
   261      *  @param site   The qualifier's type.
   262      */
   263     Symbol binaryQualifier(Symbol sym, Type site) {
   265         if (site.hasTag(ARRAY)) {
   266             if (sym == syms.lengthVar ||
   267                 sym.owner != syms.arrayClass)
   268                 return sym;
   269             // array clone can be qualified by the array type in later targets
   270             Symbol qualifier = target.arrayBinaryCompatibility()
   271                 ? new ClassSymbol(Flags.PUBLIC, site.tsym.name,
   272                                   site, syms.noSymbol)
   273                 : syms.objectType.tsym;
   274             return sym.clone(qualifier);
   275         }
   277         if (sym.owner == site.tsym ||
   278             (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
   279             return sym;
   280         }
   281         if (!target.obeyBinaryCompatibility())
   282             return rs.isAccessible(attrEnv, (TypeSymbol)sym.owner)
   283                 ? sym
   284                 : sym.clone(site.tsym);
   286         if (!target.interfaceFieldsBinaryCompatibility()) {
   287             if ((sym.owner.flags() & INTERFACE) != 0 && sym.kind == VAR)
   288                 return sym;
   289         }
   291         // leave alone methods inherited from Object
   292         // JLS 13.1.
   293         if (sym.owner == syms.objectType.tsym)
   294             return sym;
   296         if (!target.interfaceObjectOverridesBinaryCompatibility()) {
   297             if ((sym.owner.flags() & INTERFACE) != 0 &&
   298                 syms.objectType.tsym.members().lookup(sym.name).scope != null)
   299                 return sym;
   300         }
   302         return sym.clone(site.tsym);
   303     }
   305     /** Insert a reference to given type in the constant pool,
   306      *  checking for an array with too many dimensions;
   307      *  return the reference's index.
   308      *  @param type   The type for which a reference is inserted.
   309      */
   310     int makeRef(DiagnosticPosition pos, Type type) {
   311         checkDimension(pos, type);
   312         if (type.isAnnotated()) {
   313             // Treat annotated types separately - we don't want
   314             // to collapse all of them - at least for annotated
   315             // exceptions.
   316             // TODO: review this.
   317             return pool.put((Object)type);
   318         } else {
   319             return pool.put(type.hasTag(CLASS) ? (Object)type.tsym : (Object)type);
   320         }
   321     }
   323     /** Check if the given type is an array with too many dimensions.
   324      */
   325     private void checkDimension(DiagnosticPosition pos, Type t) {
   326         switch (t.getTag()) {
   327         case METHOD:
   328             checkDimension(pos, t.getReturnType());
   329             for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
   330                 checkDimension(pos, args.head);
   331             break;
   332         case ARRAY:
   333             if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
   334                 log.error(pos, "limit.dimensions");
   335                 nerrs++;
   336             }
   337             break;
   338         default:
   339             break;
   340         }
   341     }
   343     /** Create a tempory variable.
   344      *  @param type   The variable's type.
   345      */
   346     LocalItem makeTemp(Type type) {
   347         VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
   348                                     names.empty,
   349                                     type,
   350                                     env.enclMethod.sym);
   351         code.newLocal(v);
   352         return items.makeLocalItem(v);
   353     }
   355     /** Generate code to call a non-private method or constructor.
   356      *  @param pos         Position to be used for error reporting.
   357      *  @param site        The type of which the method is a member.
   358      *  @param name        The method's name.
   359      *  @param argtypes    The method's argument types.
   360      *  @param isStatic    A flag that indicates whether we call a
   361      *                     static or instance method.
   362      */
   363     void callMethod(DiagnosticPosition pos,
   364                     Type site, Name name, List<Type> argtypes,
   365                     boolean isStatic) {
   366         Symbol msym = rs.
   367             resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
   368         if (isStatic) items.makeStaticItem(msym).invoke();
   369         else items.makeMemberItem(msym, name == names.init).invoke();
   370     }
   372     /** Is the given method definition an access method
   373      *  resulting from a qualified super? This is signified by an odd
   374      *  access code.
   375      */
   376     private boolean isAccessSuper(JCMethodDecl enclMethod) {
   377         return
   378             (enclMethod.mods.flags & SYNTHETIC) != 0 &&
   379             isOddAccessName(enclMethod.name);
   380     }
   382     /** Does given name start with "access$" and end in an odd digit?
   383      */
   384     private boolean isOddAccessName(Name name) {
   385         return
   386             name.startsWith(accessDollar) &&
   387             (name.getByteAt(name.getByteLength() - 1) & 1) == 1;
   388     }
   390 /* ************************************************************************
   391  * Non-local exits
   392  *************************************************************************/
   394     /** Generate code to invoke the finalizer associated with given
   395      *  environment.
   396      *  Any calls to finalizers are appended to the environments `cont' chain.
   397      *  Mark beginning of gap in catch all range for finalizer.
   398      */
   399     void genFinalizer(Env<GenContext> env) {
   400         if (code.isAlive() && env.info.finalize != null)
   401             env.info.finalize.gen();
   402     }
   404     /** Generate code to call all finalizers of structures aborted by
   405      *  a non-local
   406      *  exit.  Return target environment of the non-local exit.
   407      *  @param target      The tree representing the structure that's aborted
   408      *  @param env         The environment current at the non-local exit.
   409      */
   410     Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
   411         Env<GenContext> env1 = env;
   412         while (true) {
   413             genFinalizer(env1);
   414             if (env1.tree == target) break;
   415             env1 = env1.next;
   416         }
   417         return env1;
   418     }
   420     /** Mark end of gap in catch-all range for finalizer.
   421      *  @param env   the environment which might contain the finalizer
   422      *               (if it does, env.info.gaps != null).
   423      */
   424     void endFinalizerGap(Env<GenContext> env) {
   425         if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
   426             env.info.gaps.append(code.curPc());
   427     }
   429     /** Mark end of all gaps in catch-all ranges for finalizers of environments
   430      *  lying between, and including to two environments.
   431      *  @param from    the most deeply nested environment to mark
   432      *  @param to      the least deeply nested environment to mark
   433      */
   434     void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
   435         Env<GenContext> last = null;
   436         while (last != to) {
   437             endFinalizerGap(from);
   438             last = from;
   439             from = from.next;
   440         }
   441     }
   443     /** Do any of the structures aborted by a non-local exit have
   444      *  finalizers that require an empty stack?
   445      *  @param target      The tree representing the structure that's aborted
   446      *  @param env         The environment current at the non-local exit.
   447      */
   448     boolean hasFinally(JCTree target, Env<GenContext> env) {
   449         while (env.tree != target) {
   450             if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
   451                 return true;
   452             env = env.next;
   453         }
   454         return false;
   455     }
   457 /* ************************************************************************
   458  * Normalizing class-members.
   459  *************************************************************************/
   461     /** Distribute member initializer code into constructors and {@code <clinit>}
   462      *  method.
   463      *  @param defs         The list of class member declarations.
   464      *  @param c            The enclosing class.
   465      */
   466     List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
   467         ListBuffer<JCStatement> initCode = new ListBuffer<JCStatement>();
   468         ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<Attribute.TypeCompound>();
   469         ListBuffer<JCStatement> clinitCode = new ListBuffer<JCStatement>();
   470         ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<Attribute.TypeCompound>();
   471         ListBuffer<JCTree> methodDefs = new ListBuffer<JCTree>();
   472         // Sort definitions into three listbuffers:
   473         //  - initCode for instance initializers
   474         //  - clinitCode for class initializers
   475         //  - methodDefs for method definitions
   476         for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
   477             JCTree def = l.head;
   478             switch (def.getTag()) {
   479             case BLOCK:
   480                 JCBlock block = (JCBlock)def;
   481                 if ((block.flags & STATIC) != 0)
   482                     clinitCode.append(block);
   483                 else
   484                     initCode.append(block);
   485                 break;
   486             case METHODDEF:
   487                 methodDefs.append(def);
   488                 break;
   489             case VARDEF:
   490                 JCVariableDecl vdef = (JCVariableDecl) def;
   491                 VarSymbol sym = vdef.sym;
   492                 checkDimension(vdef.pos(), sym.type);
   493                 if (vdef.init != null) {
   494                     if ((sym.flags() & STATIC) == 0) {
   495                         // Always initialize instance variables.
   496                         JCStatement init = make.at(vdef.pos()).
   497                             Assignment(sym, vdef.init);
   498                         initCode.append(init);
   499                         endPosTable.replaceTree(vdef, init);
   500                         initTAs.addAll(getAndRemoveNonFieldTAs(sym));
   501                     } else if (sym.getConstValue() == null) {
   502                         // Initialize class (static) variables only if
   503                         // they are not compile-time constants.
   504                         JCStatement init = make.at(vdef.pos).
   505                             Assignment(sym, vdef.init);
   506                         clinitCode.append(init);
   507                         endPosTable.replaceTree(vdef, init);
   508                         clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
   509                     } else {
   510                         checkStringConstant(vdef.init.pos(), sym.getConstValue());
   511                     }
   512                 }
   513                 break;
   514             default:
   515                 Assert.error();
   516             }
   517         }
   518         // Insert any instance initializers into all constructors.
   519         if (initCode.length() != 0) {
   520             List<JCStatement> inits = initCode.toList();
   521             initTAs.addAll(c.getInitTypeAttributes());
   522             List<Attribute.TypeCompound> initTAlist = initTAs.toList();
   523             for (JCTree t : methodDefs) {
   524                 normalizeMethod((JCMethodDecl)t, inits, initTAlist);
   525             }
   526         }
   527         // If there are class initializers, create a <clinit> method
   528         // that contains them as its body.
   529         if (clinitCode.length() != 0) {
   530             MethodSymbol clinit = new MethodSymbol(
   531                 STATIC | (c.flags() & STRICTFP),
   532                 names.clinit,
   533                 new MethodType(
   534                     List.<Type>nil(), syms.voidType,
   535                     List.<Type>nil(), syms.methodClass),
   536                 c);
   537             c.members().enter(clinit);
   538             List<JCStatement> clinitStats = clinitCode.toList();
   539             JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
   540             block.endpos = TreeInfo.endPos(clinitStats.last());
   541             methodDefs.append(make.MethodDef(clinit, block));
   543             if (!clinitTAs.isEmpty())
   544                 clinit.appendUniqueTypeAttributes(clinitTAs.toList());
   545             if (!c.getClassInitTypeAttributes().isEmpty())
   546                 clinit.appendUniqueTypeAttributes(c.getClassInitTypeAttributes());
   547         }
   548         // Return all method definitions.
   549         return methodDefs.toList();
   550     }
   552     private List<Attribute.TypeCompound> getAndRemoveNonFieldTAs(VarSymbol sym) {
   553         List<TypeCompound> tas = sym.getRawTypeAttributes();
   554         ListBuffer<Attribute.TypeCompound> fieldTAs = new ListBuffer<Attribute.TypeCompound>();
   555         ListBuffer<Attribute.TypeCompound> nonfieldTAs = new ListBuffer<Attribute.TypeCompound>();
   556         for (TypeCompound ta : tas) {
   557             if (ta.position.type == TargetType.FIELD) {
   558                 fieldTAs.add(ta);
   559             } else {
   560                 nonfieldTAs.add(ta);
   561             }
   562         }
   563         sym.setTypeAttributes(fieldTAs.toList());
   564         return nonfieldTAs.toList();
   565     }
   567     /** Check a constant value and report if it is a string that is
   568      *  too large.
   569      */
   570     private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
   571         if (nerrs != 0 || // only complain about a long string once
   572             constValue == null ||
   573             !(constValue instanceof String) ||
   574             ((String)constValue).length() < Pool.MAX_STRING_LENGTH)
   575             return;
   576         log.error(pos, "limit.string");
   577         nerrs++;
   578     }
   580     /** Insert instance initializer code into initial constructor.
   581      *  @param md        The tree potentially representing a
   582      *                   constructor's definition.
   583      *  @param initCode  The list of instance initializer statements.
   584      *  @param initTAs  Type annotations from the initializer expression.
   585      */
   586     void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<TypeCompound> initTAs) {
   587         if (md.name == names.init && TreeInfo.isInitialConstructor(md)) {
   588             // We are seeing a constructor that does not call another
   589             // constructor of the same class.
   590             List<JCStatement> stats = md.body.stats;
   591             ListBuffer<JCStatement> newstats = new ListBuffer<JCStatement>();
   593             if (stats.nonEmpty()) {
   594                 // Copy initializers of synthetic variables generated in
   595                 // the translation of inner classes.
   596                 while (TreeInfo.isSyntheticInit(stats.head)) {
   597                     newstats.append(stats.head);
   598                     stats = stats.tail;
   599                 }
   600                 // Copy superclass constructor call
   601                 newstats.append(stats.head);
   602                 stats = stats.tail;
   603                 // Copy remaining synthetic initializers.
   604                 while (stats.nonEmpty() &&
   605                        TreeInfo.isSyntheticInit(stats.head)) {
   606                     newstats.append(stats.head);
   607                     stats = stats.tail;
   608                 }
   609                 // Now insert the initializer code.
   610                 newstats.appendList(initCode);
   611                 // And copy all remaining statements.
   612                 while (stats.nonEmpty()) {
   613                     newstats.append(stats.head);
   614                     stats = stats.tail;
   615                 }
   616             }
   617             md.body.stats = newstats.toList();
   618             if (md.body.endpos == Position.NOPOS)
   619                 md.body.endpos = TreeInfo.endPos(md.body.stats.last());
   621             md.sym.appendUniqueTypeAttributes(initTAs);
   622         }
   623     }
   625 /* ********************************************************************
   626  * Adding miranda methods
   627  *********************************************************************/
   629     /** Add abstract methods for all methods defined in one of
   630      *  the interfaces of a given class,
   631      *  provided they are not already implemented in the class.
   632      *
   633      *  @param c      The class whose interfaces are searched for methods
   634      *                for which Miranda methods should be added.
   635      */
   636     void implementInterfaceMethods(ClassSymbol c) {
   637         implementInterfaceMethods(c, c);
   638     }
   640     /** Add abstract methods for all methods defined in one of
   641      *  the interfaces of a given class,
   642      *  provided they are not already implemented in the class.
   643      *
   644      *  @param c      The class whose interfaces are searched for methods
   645      *                for which Miranda methods should be added.
   646      *  @param site   The class in which a definition may be needed.
   647      */
   648     void implementInterfaceMethods(ClassSymbol c, ClassSymbol site) {
   649         for (List<Type> l = types.interfaces(c.type); l.nonEmpty(); l = l.tail) {
   650             ClassSymbol i = (ClassSymbol)l.head.tsym;
   651             for (Scope.Entry e = i.members().elems;
   652                  e != null;
   653                  e = e.sibling)
   654             {
   655                 if (e.sym.kind == MTH && (e.sym.flags() & STATIC) == 0)
   656                 {
   657                     MethodSymbol absMeth = (MethodSymbol)e.sym;
   658                     MethodSymbol implMeth = absMeth.binaryImplementation(site, types);
   659                     if (implMeth == null)
   660                         addAbstractMethod(site, absMeth);
   661                     else if ((implMeth.flags() & IPROXY) != 0)
   662                         adjustAbstractMethod(site, implMeth, absMeth);
   663                 }
   664             }
   665             implementInterfaceMethods(i, site);
   666         }
   667     }
   669     /** Add an abstract methods to a class
   670      *  which implicitly implements a method defined in some interface
   671      *  implemented by the class. These methods are called "Miranda methods".
   672      *  Enter the newly created method into its enclosing class scope.
   673      *  Note that it is not entered into the class tree, as the emitter
   674      *  doesn't need to see it there to emit an abstract method.
   675      *
   676      *  @param c      The class to which the Miranda method is added.
   677      *  @param m      The interface method symbol for which a Miranda method
   678      *                is added.
   679      */
   680     private void addAbstractMethod(ClassSymbol c,
   681                                    MethodSymbol m) {
   682         MethodSymbol absMeth = new MethodSymbol(
   683             m.flags() | IPROXY | SYNTHETIC, m.name,
   684             m.type, // was c.type.memberType(m), but now only !generics supported
   685             c);
   686         c.members().enter(absMeth); // add to symbol table
   687     }
   689     private void adjustAbstractMethod(ClassSymbol c,
   690                                       MethodSymbol pm,
   691                                       MethodSymbol im) {
   692         MethodType pmt = (MethodType)pm.type;
   693         Type imt = types.memberType(c.type, im);
   694         pmt.thrown = chk.intersect(pmt.getThrownTypes(), imt.getThrownTypes());
   695     }
   697 /* ************************************************************************
   698  * Traversal methods
   699  *************************************************************************/
   701     /** Visitor argument: The current environment.
   702      */
   703     Env<GenContext> env;
   705     /** Visitor argument: The expected type (prototype).
   706      */
   707     Type pt;
   709     /** Visitor result: The item representing the computed value.
   710      */
   711     Item result;
   713     /** Visitor method: generate code for a definition, catching and reporting
   714      *  any completion failures.
   715      *  @param tree    The definition to be visited.
   716      *  @param env     The environment current at the definition.
   717      */
   718     public void genDef(JCTree tree, Env<GenContext> env) {
   719         Env<GenContext> prevEnv = this.env;
   720         try {
   721             this.env = env;
   722             tree.accept(this);
   723         } catch (CompletionFailure ex) {
   724             chk.completionError(tree.pos(), ex);
   725         } finally {
   726             this.env = prevEnv;
   727         }
   728     }
   730     /** Derived visitor method: check whether CharacterRangeTable
   731      *  should be emitted, if so, put a new entry into CRTable
   732      *  and call method to generate bytecode.
   733      *  If not, just call method to generate bytecode.
   734      *  @see    #genStat(JCTree, Env)
   735      *
   736      *  @param  tree     The tree to be visited.
   737      *  @param  env      The environment to use.
   738      *  @param  crtFlags The CharacterRangeTable flags
   739      *                   indicating type of the entry.
   740      */
   741     public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
   742         if (!genCrt) {
   743             genStat(tree, env);
   744             return;
   745         }
   746         int startpc = code.curPc();
   747         genStat(tree, env);
   748         if (tree.hasTag(Tag.BLOCK)) crtFlags |= CRT_BLOCK;
   749         code.crt.put(tree, crtFlags, startpc, code.curPc());
   750     }
   752     /** Derived visitor method: generate code for a statement.
   753      */
   754     public void genStat(JCTree tree, Env<GenContext> env) {
   755         if (code.isAlive()) {
   756             code.statBegin(tree.pos);
   757             genDef(tree, env);
   758         } else if (env.info.isSwitch && tree.hasTag(VARDEF)) {
   759             // variables whose declarations are in a switch
   760             // can be used even if the decl is unreachable.
   761             code.newLocal(((JCVariableDecl) tree).sym);
   762         }
   763     }
   765     /** Derived visitor method: check whether CharacterRangeTable
   766      *  should be emitted, if so, put a new entry into CRTable
   767      *  and call method to generate bytecode.
   768      *  If not, just call method to generate bytecode.
   769      *  @see    #genStats(List, Env)
   770      *
   771      *  @param  trees    The list of trees to be visited.
   772      *  @param  env      The environment to use.
   773      *  @param  crtFlags The CharacterRangeTable flags
   774      *                   indicating type of the entry.
   775      */
   776     public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
   777         if (!genCrt) {
   778             genStats(trees, env);
   779             return;
   780         }
   781         if (trees.length() == 1) {        // mark one statement with the flags
   782             genStat(trees.head, env, crtFlags | CRT_STATEMENT);
   783         } else {
   784             int startpc = code.curPc();
   785             genStats(trees, env);
   786             code.crt.put(trees, crtFlags, startpc, code.curPc());
   787         }
   788     }
   790     /** Derived visitor method: generate code for a list of statements.
   791      */
   792     public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
   793         for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
   794             genStat(l.head, env, CRT_STATEMENT);
   795     }
   797     /** Derived visitor method: check whether CharacterRangeTable
   798      *  should be emitted, if so, put a new entry into CRTable
   799      *  and call method to generate bytecode.
   800      *  If not, just call method to generate bytecode.
   801      *  @see    #genCond(JCTree,boolean)
   802      *
   803      *  @param  tree     The tree to be visited.
   804      *  @param  crtFlags The CharacterRangeTable flags
   805      *                   indicating type of the entry.
   806      */
   807     public CondItem genCond(JCTree tree, int crtFlags) {
   808         if (!genCrt) return genCond(tree, false);
   809         int startpc = code.curPc();
   810         CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
   811         code.crt.put(tree, crtFlags, startpc, code.curPc());
   812         return item;
   813     }
   815     /** Derived visitor method: generate code for a boolean
   816      *  expression in a control-flow context.
   817      *  @param _tree         The expression to be visited.
   818      *  @param markBranches The flag to indicate that the condition is
   819      *                      a flow controller so produced conditions
   820      *                      should contain a proper tree to generate
   821      *                      CharacterRangeTable branches for them.
   822      */
   823     public CondItem genCond(JCTree _tree, boolean markBranches) {
   824         JCTree inner_tree = TreeInfo.skipParens(_tree);
   825         if (inner_tree.hasTag(CONDEXPR)) {
   826             JCConditional tree = (JCConditional)inner_tree;
   827             CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
   828             if (cond.isTrue()) {
   829                 code.resolve(cond.trueJumps);
   830                 CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
   831                 if (markBranches) result.tree = tree.truepart;
   832                 return result;
   833             }
   834             if (cond.isFalse()) {
   835                 code.resolve(cond.falseJumps);
   836                 CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
   837                 if (markBranches) result.tree = tree.falsepart;
   838                 return result;
   839             }
   840             Chain secondJumps = cond.jumpFalse();
   841             code.resolve(cond.trueJumps);
   842             CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
   843             if (markBranches) first.tree = tree.truepart;
   844             Chain falseJumps = first.jumpFalse();
   845             code.resolve(first.trueJumps);
   846             Chain trueJumps = code.branch(goto_);
   847             code.resolve(secondJumps);
   848             CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
   849             CondItem result = items.makeCondItem(second.opcode,
   850                                       Code.mergeChains(trueJumps, second.trueJumps),
   851                                       Code.mergeChains(falseJumps, second.falseJumps));
   852             if (markBranches) result.tree = tree.falsepart;
   853             return result;
   854         } else {
   855             CondItem result = genExpr(_tree, syms.booleanType).mkCond();
   856             if (markBranches) result.tree = _tree;
   857             return result;
   858         }
   859     }
   861     /** Visitor class for expressions which might be constant expressions.
   862      *  This class is a subset of TreeScanner. Intended to visit trees pruned by
   863      *  Lower as long as constant expressions looking for references to any
   864      *  ClassSymbol. Any such reference will be added to the constant pool so
   865      *  automated tools can detect class dependencies better.
   866      */
   867     class ClassReferenceVisitor extends JCTree.Visitor {
   869         @Override
   870         public void visitTree(JCTree tree) {}
   872         @Override
   873         public void visitBinary(JCBinary tree) {
   874             tree.lhs.accept(this);
   875             tree.rhs.accept(this);
   876         }
   878         @Override
   879         public void visitSelect(JCFieldAccess tree) {
   880             if (tree.selected.type.hasTag(CLASS)) {
   881                 makeRef(tree.selected.pos(), tree.selected.type);
   882             }
   883         }
   885         @Override
   886         public void visitIdent(JCIdent tree) {
   887             if (tree.sym.owner instanceof ClassSymbol) {
   888                 pool.put(tree.sym.owner);
   889             }
   890         }
   892         @Override
   893         public void visitConditional(JCConditional tree) {
   894             tree.cond.accept(this);
   895             tree.truepart.accept(this);
   896             tree.falsepart.accept(this);
   897         }
   899         @Override
   900         public void visitUnary(JCUnary tree) {
   901             tree.arg.accept(this);
   902         }
   904         @Override
   905         public void visitParens(JCParens tree) {
   906             tree.expr.accept(this);
   907         }
   909         @Override
   910         public void visitTypeCast(JCTypeCast tree) {
   911             tree.expr.accept(this);
   912         }
   913     }
   915     private ClassReferenceVisitor classReferenceVisitor = new ClassReferenceVisitor();
   917     /** Visitor method: generate code for an expression, catching and reporting
   918      *  any completion failures.
   919      *  @param tree    The expression to be visited.
   920      *  @param pt      The expression's expected type (proto-type).
   921      */
   922     public Item genExpr(JCTree tree, Type pt) {
   923         Type prevPt = this.pt;
   924         try {
   925             if (tree.type.constValue() != null) {
   926                 // Short circuit any expressions which are constants
   927                 tree.accept(classReferenceVisitor);
   928                 checkStringConstant(tree.pos(), tree.type.constValue());
   929                 result = items.makeImmediateItem(tree.type, tree.type.constValue());
   930             } else {
   931                 this.pt = pt;
   932                 tree.accept(this);
   933             }
   934             return result.coerce(pt);
   935         } catch (CompletionFailure ex) {
   936             chk.completionError(tree.pos(), ex);
   937             code.state.stacksize = 1;
   938             return items.makeStackItem(pt);
   939         } finally {
   940             this.pt = prevPt;
   941         }
   942     }
   944     /** Derived visitor method: generate code for a list of method arguments.
   945      *  @param trees    The argument expressions to be visited.
   946      *  @param pts      The expression's expected types (i.e. the formal parameter
   947      *                  types of the invoked method).
   948      */
   949     public void genArgs(List<JCExpression> trees, List<Type> pts) {
   950         for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail) {
   951             genExpr(l.head, pts.head).load();
   952             pts = pts.tail;
   953         }
   954         // require lists be of same length
   955         Assert.check(pts.isEmpty());
   956     }
   958 /* ************************************************************************
   959  * Visitor methods for statements and definitions
   960  *************************************************************************/
   962     /** Thrown when the byte code size exceeds limit.
   963      */
   964     public static class CodeSizeOverflow extends RuntimeException {
   965         private static final long serialVersionUID = 0;
   966         public CodeSizeOverflow() {}
   967     }
   969     public void visitMethodDef(JCMethodDecl tree) {
   970         // Create a new local environment that points pack at method
   971         // definition.
   972         Env<GenContext> localEnv = env.dup(tree);
   973         localEnv.enclMethod = tree;
   975         // The expected type of every return statement in this method
   976         // is the method's return type.
   977         this.pt = tree.sym.erasure(types).getReturnType();
   979         checkDimension(tree.pos(), tree.sym.erasure(types));
   980         genMethod(tree, localEnv, false);
   981     }
   982 //where
   983         /** Generate code for a method.
   984          *  @param tree     The tree representing the method definition.
   985          *  @param env      The environment current for the method body.
   986          *  @param fatcode  A flag that indicates whether all jumps are
   987          *                  within 32K.  We first invoke this method under
   988          *                  the assumption that fatcode == false, i.e. all
   989          *                  jumps are within 32K.  If this fails, fatcode
   990          *                  is set to true and we try again.
   991          */
   992         void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
   993             MethodSymbol meth = tree.sym;
   994             int extras = 0;
   995             // Count up extra parameters
   996             if (meth.isConstructor()) {
   997                 extras++;
   998                 if (meth.enclClass().isInner() &&
   999                     !meth.enclClass().isStatic()) {
  1000                     extras++;
  1002             } else if ((tree.mods.flags & STATIC) == 0) {
  1003                 extras++;
  1005             //      System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
  1006             if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
  1007                 ClassFile.MAX_PARAMETERS) {
  1008                 log.error(tree.pos(), "limit.parameters");
  1009                 nerrs++;
  1012             else if (tree.body != null) {
  1013                 // Create a new code structure and initialize it.
  1014                 int startpcCrt = initCode(tree, env, fatcode);
  1016                 try {
  1017                     genStat(tree.body, env);
  1018                 } catch (CodeSizeOverflow e) {
  1019                     // Failed due to code limit, try again with jsr/ret
  1020                     startpcCrt = initCode(tree, env, fatcode);
  1021                     genStat(tree.body, env);
  1024                 if (code.state.stacksize != 0) {
  1025                     log.error(tree.body.pos(), "stack.sim.error", tree);
  1026                     throw new AssertionError();
  1029                 // If last statement could complete normally, insert a
  1030                 // return at the end.
  1031                 if (code.isAlive()) {
  1032                     code.statBegin(TreeInfo.endPos(tree.body));
  1033                     if (env.enclMethod == null ||
  1034                         env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
  1035                         code.emitop0(return_);
  1036                     } else {
  1037                         // sometime dead code seems alive (4415991);
  1038                         // generate a small loop instead
  1039                         int startpc = code.entryPoint();
  1040                         CondItem c = items.makeCondItem(goto_);
  1041                         code.resolve(c.jumpTrue(), startpc);
  1044                 if (genCrt)
  1045                     code.crt.put(tree.body,
  1046                                  CRT_BLOCK,
  1047                                  startpcCrt,
  1048                                  code.curPc());
  1050                 code.endScopes(0);
  1052                 // If we exceeded limits, panic
  1053                 if (code.checkLimits(tree.pos(), log)) {
  1054                     nerrs++;
  1055                     return;
  1058                 // If we generated short code but got a long jump, do it again
  1059                 // with fatCode = true.
  1060                 if (!fatcode && code.fatcode) genMethod(tree, env, true);
  1062                 // Clean up
  1063                 if(stackMap == StackMapFormat.JSR202) {
  1064                     code.lastFrame = null;
  1065                     code.frameBeforeLast = null;
  1068                 // Compress exception table
  1069                 code.compressCatchTable();
  1071                 // Fill in type annotation positions for exception parameters
  1072                 code.fillExceptionParameterPositions();
  1076         private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
  1077             MethodSymbol meth = tree.sym;
  1079             // Create a new code structure.
  1080             meth.code = code = new Code(meth,
  1081                                         fatcode,
  1082                                         lineDebugInfo ? toplevel.lineMap : null,
  1083                                         varDebugInfo,
  1084                                         stackMap,
  1085                                         debugCode,
  1086                                         genCrt ? new CRTable(tree, env.toplevel.endPositions)
  1087                                                : null,
  1088                                         syms,
  1089                                         types,
  1090                                         pool);
  1091             items = new Items(pool, code, syms, types);
  1092             if (code.debugCode)
  1093                 System.err.println(meth + " for body " + tree);
  1095             // If method is not static, create a new local variable address
  1096             // for `this'.
  1097             if ((tree.mods.flags & STATIC) == 0) {
  1098                 Type selfType = meth.owner.type;
  1099                 if (meth.isConstructor() && selfType != syms.objectType)
  1100                     selfType = UninitializedType.uninitializedThis(selfType);
  1101                 code.setDefined(
  1102                         code.newLocal(
  1103                             new VarSymbol(FINAL, names._this, selfType, meth.owner)));
  1106             // Mark all parameters as defined from the beginning of
  1107             // the method.
  1108             for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
  1109                 checkDimension(l.head.pos(), l.head.sym.type);
  1110                 code.setDefined(code.newLocal(l.head.sym));
  1113             // Get ready to generate code for method body.
  1114             int startpcCrt = genCrt ? code.curPc() : 0;
  1115             code.entryPoint();
  1117             // Suppress initial stackmap
  1118             code.pendingStackMap = false;
  1120             return startpcCrt;
  1123     public void visitVarDef(JCVariableDecl tree) {
  1124         VarSymbol v = tree.sym;
  1125         code.newLocal(v);
  1126         if (tree.init != null) {
  1127             checkStringConstant(tree.init.pos(), v.getConstValue());
  1128             if (v.getConstValue() == null || varDebugInfo) {
  1129                 genExpr(tree.init, v.erasure(types)).load();
  1130                 items.makeLocalItem(v).store();
  1133         checkDimension(tree.pos(), v.type);
  1136     public void visitSkip(JCSkip tree) {
  1139     public void visitBlock(JCBlock tree) {
  1140         int limit = code.nextreg;
  1141         Env<GenContext> localEnv = env.dup(tree, new GenContext());
  1142         genStats(tree.stats, localEnv);
  1143         // End the scope of all block-local variables in variable info.
  1144         if (!env.tree.hasTag(METHODDEF)) {
  1145             code.statBegin(tree.endpos);
  1146             code.endScopes(limit);
  1147             code.pendingStatPos = Position.NOPOS;
  1151     public void visitDoLoop(JCDoWhileLoop tree) {
  1152         genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), false);
  1155     public void visitWhileLoop(JCWhileLoop tree) {
  1156         genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), true);
  1159     public void visitForLoop(JCForLoop tree) {
  1160         int limit = code.nextreg;
  1161         genStats(tree.init, env);
  1162         genLoop(tree, tree.body, tree.cond, tree.step, true);
  1163         code.endScopes(limit);
  1165     //where
  1166         /** Generate code for a loop.
  1167          *  @param loop       The tree representing the loop.
  1168          *  @param body       The loop's body.
  1169          *  @param cond       The loop's controling condition.
  1170          *  @param step       "Step" statements to be inserted at end of
  1171          *                    each iteration.
  1172          *  @param testFirst  True if the loop test belongs before the body.
  1173          */
  1174         private void genLoop(JCStatement loop,
  1175                              JCStatement body,
  1176                              JCExpression cond,
  1177                              List<JCExpressionStatement> step,
  1178                              boolean testFirst) {
  1179             Env<GenContext> loopEnv = env.dup(loop, new GenContext());
  1180             int startpc = code.entryPoint();
  1181             if (testFirst) {
  1182                 CondItem c;
  1183                 if (cond != null) {
  1184                     code.statBegin(cond.pos);
  1185                     c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
  1186                 } else {
  1187                     c = items.makeCondItem(goto_);
  1189                 Chain loopDone = c.jumpFalse();
  1190                 code.resolve(c.trueJumps);
  1191                 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
  1192                 code.resolve(loopEnv.info.cont);
  1193                 genStats(step, loopEnv);
  1194                 code.resolve(code.branch(goto_), startpc);
  1195                 code.resolve(loopDone);
  1196             } else {
  1197                 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
  1198                 code.resolve(loopEnv.info.cont);
  1199                 genStats(step, loopEnv);
  1200                 CondItem c;
  1201                 if (cond != null) {
  1202                     code.statBegin(cond.pos);
  1203                     c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
  1204                 } else {
  1205                     c = items.makeCondItem(goto_);
  1207                 code.resolve(c.jumpTrue(), startpc);
  1208                 code.resolve(c.falseJumps);
  1210             code.resolve(loopEnv.info.exit);
  1213     public void visitForeachLoop(JCEnhancedForLoop tree) {
  1214         throw new AssertionError(); // should have been removed by Lower.
  1217     public void visitLabelled(JCLabeledStatement tree) {
  1218         Env<GenContext> localEnv = env.dup(tree, new GenContext());
  1219         genStat(tree.body, localEnv, CRT_STATEMENT);
  1220         code.resolve(localEnv.info.exit);
  1223     public void visitSwitch(JCSwitch tree) {
  1224         int limit = code.nextreg;
  1225         Assert.check(!tree.selector.type.hasTag(CLASS));
  1226         int startpcCrt = genCrt ? code.curPc() : 0;
  1227         Item sel = genExpr(tree.selector, syms.intType);
  1228         List<JCCase> cases = tree.cases;
  1229         if (cases.isEmpty()) {
  1230             // We are seeing:  switch <sel> {}
  1231             sel.load().drop();
  1232             if (genCrt)
  1233                 code.crt.put(TreeInfo.skipParens(tree.selector),
  1234                              CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
  1235         } else {
  1236             // We are seeing a nonempty switch.
  1237             sel.load();
  1238             if (genCrt)
  1239                 code.crt.put(TreeInfo.skipParens(tree.selector),
  1240                              CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
  1241             Env<GenContext> switchEnv = env.dup(tree, new GenContext());
  1242             switchEnv.info.isSwitch = true;
  1244             // Compute number of labels and minimum and maximum label values.
  1245             // For each case, store its label in an array.
  1246             int lo = Integer.MAX_VALUE;  // minimum label.
  1247             int hi = Integer.MIN_VALUE;  // maximum label.
  1248             int nlabels = 0;               // number of labels.
  1250             int[] labels = new int[cases.length()];  // the label array.
  1251             int defaultIndex = -1;     // the index of the default clause.
  1253             List<JCCase> l = cases;
  1254             for (int i = 0; i < labels.length; i++) {
  1255                 if (l.head.pat != null) {
  1256                     int val = ((Number)l.head.pat.type.constValue()).intValue();
  1257                     labels[i] = val;
  1258                     if (val < lo) lo = val;
  1259                     if (hi < val) hi = val;
  1260                     nlabels++;
  1261                 } else {
  1262                     Assert.check(defaultIndex == -1);
  1263                     defaultIndex = i;
  1265                 l = l.tail;
  1268             // Determine whether to issue a tableswitch or a lookupswitch
  1269             // instruction.
  1270             long table_space_cost = 4 + ((long) hi - lo + 1); // words
  1271             long table_time_cost = 3; // comparisons
  1272             long lookup_space_cost = 3 + 2 * (long) nlabels;
  1273             long lookup_time_cost = nlabels;
  1274             int opcode =
  1275                 nlabels > 0 &&
  1276                 table_space_cost + 3 * table_time_cost <=
  1277                 lookup_space_cost + 3 * lookup_time_cost
  1279                 tableswitch : lookupswitch;
  1281             int startpc = code.curPc();    // the position of the selector operation
  1282             code.emitop0(opcode);
  1283             code.align(4);
  1284             int tableBase = code.curPc();  // the start of the jump table
  1285             int[] offsets = null;          // a table of offsets for a lookupswitch
  1286             code.emit4(-1);                // leave space for default offset
  1287             if (opcode == tableswitch) {
  1288                 code.emit4(lo);            // minimum label
  1289                 code.emit4(hi);            // maximum label
  1290                 for (long i = lo; i <= hi; i++) {  // leave space for jump table
  1291                     code.emit4(-1);
  1293             } else {
  1294                 code.emit4(nlabels);    // number of labels
  1295                 for (int i = 0; i < nlabels; i++) {
  1296                     code.emit4(-1); code.emit4(-1); // leave space for lookup table
  1298                 offsets = new int[labels.length];
  1300             Code.State stateSwitch = code.state.dup();
  1301             code.markDead();
  1303             // For each case do:
  1304             l = cases;
  1305             for (int i = 0; i < labels.length; i++) {
  1306                 JCCase c = l.head;
  1307                 l = l.tail;
  1309                 int pc = code.entryPoint(stateSwitch);
  1310                 // Insert offset directly into code or else into the
  1311                 // offsets table.
  1312                 if (i != defaultIndex) {
  1313                     if (opcode == tableswitch) {
  1314                         code.put4(
  1315                             tableBase + 4 * (labels[i] - lo + 3),
  1316                             pc - startpc);
  1317                     } else {
  1318                         offsets[i] = pc - startpc;
  1320                 } else {
  1321                     code.put4(tableBase, pc - startpc);
  1324                 // Generate code for the statements in this case.
  1325                 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
  1328             // Resolve all breaks.
  1329             code.resolve(switchEnv.info.exit);
  1331             // If we have not set the default offset, we do so now.
  1332             if (code.get4(tableBase) == -1) {
  1333                 code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
  1336             if (opcode == tableswitch) {
  1337                 // Let any unfilled slots point to the default case.
  1338                 int defaultOffset = code.get4(tableBase);
  1339                 for (long i = lo; i <= hi; i++) {
  1340                     int t = (int)(tableBase + 4 * (i - lo + 3));
  1341                     if (code.get4(t) == -1)
  1342                         code.put4(t, defaultOffset);
  1344             } else {
  1345                 // Sort non-default offsets and copy into lookup table.
  1346                 if (defaultIndex >= 0)
  1347                     for (int i = defaultIndex; i < labels.length - 1; i++) {
  1348                         labels[i] = labels[i+1];
  1349                         offsets[i] = offsets[i+1];
  1351                 if (nlabels > 0)
  1352                     qsort2(labels, offsets, 0, nlabels - 1);
  1353                 for (int i = 0; i < nlabels; i++) {
  1354                     int caseidx = tableBase + 8 * (i + 1);
  1355                     code.put4(caseidx, labels[i]);
  1356                     code.put4(caseidx + 4, offsets[i]);
  1360         code.endScopes(limit);
  1362 //where
  1363         /** Sort (int) arrays of keys and values
  1364          */
  1365        static void qsort2(int[] keys, int[] values, int lo, int hi) {
  1366             int i = lo;
  1367             int j = hi;
  1368             int pivot = keys[(i+j)/2];
  1369             do {
  1370                 while (keys[i] < pivot) i++;
  1371                 while (pivot < keys[j]) j--;
  1372                 if (i <= j) {
  1373                     int temp1 = keys[i];
  1374                     keys[i] = keys[j];
  1375                     keys[j] = temp1;
  1376                     int temp2 = values[i];
  1377                     values[i] = values[j];
  1378                     values[j] = temp2;
  1379                     i++;
  1380                     j--;
  1382             } while (i <= j);
  1383             if (lo < j) qsort2(keys, values, lo, j);
  1384             if (i < hi) qsort2(keys, values, i, hi);
  1387     public void visitSynchronized(JCSynchronized tree) {
  1388         int limit = code.nextreg;
  1389         // Generate code to evaluate lock and save in temporary variable.
  1390         final LocalItem lockVar = makeTemp(syms.objectType);
  1391         genExpr(tree.lock, tree.lock.type).load().duplicate();
  1392         lockVar.store();
  1394         // Generate code to enter monitor.
  1395         code.emitop0(monitorenter);
  1396         code.state.lock(lockVar.reg);
  1398         // Generate code for a try statement with given body, no catch clauses
  1399         // in a new environment with the "exit-monitor" operation as finalizer.
  1400         final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
  1401         syncEnv.info.finalize = new GenFinalizer() {
  1402             void gen() {
  1403                 genLast();
  1404                 Assert.check(syncEnv.info.gaps.length() % 2 == 0);
  1405                 syncEnv.info.gaps.append(code.curPc());
  1407             void genLast() {
  1408                 if (code.isAlive()) {
  1409                     lockVar.load();
  1410                     code.emitop0(monitorexit);
  1411                     code.state.unlock(lockVar.reg);
  1414         };
  1415         syncEnv.info.gaps = new ListBuffer<Integer>();
  1416         genTry(tree.body, List.<JCCatch>nil(), syncEnv);
  1417         code.endScopes(limit);
  1420     public void visitTry(final JCTry tree) {
  1421         // Generate code for a try statement with given body and catch clauses,
  1422         // in a new environment which calls the finally block if there is one.
  1423         final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
  1424         final Env<GenContext> oldEnv = env;
  1425         if (!useJsrLocally) {
  1426             useJsrLocally =
  1427                 (stackMap == StackMapFormat.NONE) &&
  1428                 (jsrlimit <= 0 ||
  1429                 jsrlimit < 100 &&
  1430                 estimateCodeComplexity(tree.finalizer)>jsrlimit);
  1432         tryEnv.info.finalize = new GenFinalizer() {
  1433             void gen() {
  1434                 if (useJsrLocally) {
  1435                     if (tree.finalizer != null) {
  1436                         Code.State jsrState = code.state.dup();
  1437                         jsrState.push(Code.jsrReturnValue);
  1438                         tryEnv.info.cont =
  1439                             new Chain(code.emitJump(jsr),
  1440                                       tryEnv.info.cont,
  1441                                       jsrState);
  1443                     Assert.check(tryEnv.info.gaps.length() % 2 == 0);
  1444                     tryEnv.info.gaps.append(code.curPc());
  1445                 } else {
  1446                     Assert.check(tryEnv.info.gaps.length() % 2 == 0);
  1447                     tryEnv.info.gaps.append(code.curPc());
  1448                     genLast();
  1451             void genLast() {
  1452                 if (tree.finalizer != null)
  1453                     genStat(tree.finalizer, oldEnv, CRT_BLOCK);
  1455             boolean hasFinalizer() {
  1456                 return tree.finalizer != null;
  1458         };
  1459         tryEnv.info.gaps = new ListBuffer<Integer>();
  1460         genTry(tree.body, tree.catchers, tryEnv);
  1462     //where
  1463         /** Generate code for a try or synchronized statement
  1464          *  @param body      The body of the try or synchronized statement.
  1465          *  @param catchers  The lis of catch clauses.
  1466          *  @param env       the environment current for the body.
  1467          */
  1468         void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
  1469             int limit = code.nextreg;
  1470             int startpc = code.curPc();
  1471             Code.State stateTry = code.state.dup();
  1472             genStat(body, env, CRT_BLOCK);
  1473             int endpc = code.curPc();
  1474             boolean hasFinalizer =
  1475                 env.info.finalize != null &&
  1476                 env.info.finalize.hasFinalizer();
  1477             List<Integer> gaps = env.info.gaps.toList();
  1478             code.statBegin(TreeInfo.endPos(body));
  1479             genFinalizer(env);
  1480             code.statBegin(TreeInfo.endPos(env.tree));
  1481             Chain exitChain = code.branch(goto_);
  1482             endFinalizerGap(env);
  1483             if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
  1484                 // start off with exception on stack
  1485                 code.entryPoint(stateTry, l.head.param.sym.type);
  1486                 genCatch(l.head, env, startpc, endpc, gaps);
  1487                 genFinalizer(env);
  1488                 if (hasFinalizer || l.tail.nonEmpty()) {
  1489                     code.statBegin(TreeInfo.endPos(env.tree));
  1490                     exitChain = Code.mergeChains(exitChain,
  1491                                                  code.branch(goto_));
  1493                 endFinalizerGap(env);
  1495             if (hasFinalizer) {
  1496                 // Create a new register segement to avoid allocating
  1497                 // the same variables in finalizers and other statements.
  1498                 code.newRegSegment();
  1500                 // Add a catch-all clause.
  1502                 // start off with exception on stack
  1503                 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
  1505                 // Register all exception ranges for catch all clause.
  1506                 // The range of the catch all clause is from the beginning
  1507                 // of the try or synchronized block until the present
  1508                 // code pointer excluding all gaps in the current
  1509                 // environment's GenContext.
  1510                 int startseg = startpc;
  1511                 while (env.info.gaps.nonEmpty()) {
  1512                     int endseg = env.info.gaps.next().intValue();
  1513                     registerCatch(body.pos(), startseg, endseg,
  1514                                   catchallpc, 0);
  1515                     startseg = env.info.gaps.next().intValue();
  1517                 code.statBegin(TreeInfo.finalizerPos(env.tree));
  1518                 code.markStatBegin();
  1520                 Item excVar = makeTemp(syms.throwableType);
  1521                 excVar.store();
  1522                 genFinalizer(env);
  1523                 excVar.load();
  1524                 registerCatch(body.pos(), startseg,
  1525                               env.info.gaps.next().intValue(),
  1526                               catchallpc, 0);
  1527                 code.emitop0(athrow);
  1528                 code.markDead();
  1530                 // If there are jsr's to this finalizer, ...
  1531                 if (env.info.cont != null) {
  1532                     // Resolve all jsr's.
  1533                     code.resolve(env.info.cont);
  1535                     // Mark statement line number
  1536                     code.statBegin(TreeInfo.finalizerPos(env.tree));
  1537                     code.markStatBegin();
  1539                     // Save return address.
  1540                     LocalItem retVar = makeTemp(syms.throwableType);
  1541                     retVar.store();
  1543                     // Generate finalizer code.
  1544                     env.info.finalize.genLast();
  1546                     // Return.
  1547                     code.emitop1w(ret, retVar.reg);
  1548                     code.markDead();
  1551             // Resolve all breaks.
  1552             code.resolve(exitChain);
  1554             code.endScopes(limit);
  1557         /** Generate code for a catch clause.
  1558          *  @param tree     The catch clause.
  1559          *  @param env      The environment current in the enclosing try.
  1560          *  @param startpc  Start pc of try-block.
  1561          *  @param endpc    End pc of try-block.
  1562          */
  1563         void genCatch(JCCatch tree,
  1564                       Env<GenContext> env,
  1565                       int startpc, int endpc,
  1566                       List<Integer> gaps) {
  1567             if (startpc != endpc) {
  1568                 List<JCExpression> subClauses = TreeInfo.isMultiCatch(tree) ?
  1569                         ((JCTypeUnion)tree.param.vartype).alternatives :
  1570                         List.of(tree.param.vartype);
  1571                 while (gaps.nonEmpty()) {
  1572                     for (JCExpression subCatch : subClauses) {
  1573                         int catchType = makeRef(tree.pos(), subCatch.type);
  1574                         int end = gaps.head.intValue();
  1575                         registerCatch(tree.pos(),
  1576                                       startpc,  end, code.curPc(),
  1577                                       catchType);
  1578                         if (subCatch.type.isAnnotated()) {
  1579                             // All compounds share the same position, simply update the
  1580                             // first one.
  1581                             subCatch.type.getAnnotationMirrors().head.position.type_index = catchType;
  1584                     gaps = gaps.tail;
  1585                     startpc = gaps.head.intValue();
  1586                     gaps = gaps.tail;
  1588                 if (startpc < endpc) {
  1589                     for (JCExpression subCatch : subClauses) {
  1590                         int catchType = makeRef(tree.pos(), subCatch.type);
  1591                         registerCatch(tree.pos(),
  1592                                       startpc, endpc, code.curPc(),
  1593                                       catchType);
  1594                         if (subCatch.type.isAnnotated()) {
  1595                             // All compounds share the same position, simply update the
  1596                             // first one.
  1597                             subCatch.type.getAnnotationMirrors().head.position.type_index = catchType;
  1601                 VarSymbol exparam = tree.param.sym;
  1602                 code.statBegin(tree.pos);
  1603                 code.markStatBegin();
  1604                 int limit = code.nextreg;
  1605                 int exlocal = code.newLocal(exparam);
  1606                 items.makeLocalItem(exparam).store();
  1607                 code.statBegin(TreeInfo.firstStatPos(tree.body));
  1608                 genStat(tree.body, env, CRT_BLOCK);
  1609                 code.endScopes(limit);
  1610                 code.statBegin(TreeInfo.endPos(tree.body));
  1614         /** Register a catch clause in the "Exceptions" code-attribute.
  1615          */
  1616         void registerCatch(DiagnosticPosition pos,
  1617                            int startpc, int endpc,
  1618                            int handler_pc, int catch_type) {
  1619             char startpc1 = (char)startpc;
  1620             char endpc1 = (char)endpc;
  1621             char handler_pc1 = (char)handler_pc;
  1622             if (startpc1 == startpc &&
  1623                 endpc1 == endpc &&
  1624                 handler_pc1 == handler_pc) {
  1625                 code.addCatch(startpc1, endpc1, handler_pc1,
  1626                               (char)catch_type);
  1627             } else {
  1628                 if (!useJsrLocally && !target.generateStackMapTable()) {
  1629                     useJsrLocally = true;
  1630                     throw new CodeSizeOverflow();
  1631                 } else {
  1632                     log.error(pos, "limit.code.too.large.for.try.stmt");
  1633                     nerrs++;
  1638     /** Very roughly estimate the number of instructions needed for
  1639      *  the given tree.
  1640      */
  1641     int estimateCodeComplexity(JCTree tree) {
  1642         if (tree == null) return 0;
  1643         class ComplexityScanner extends TreeScanner {
  1644             int complexity = 0;
  1645             public void scan(JCTree tree) {
  1646                 if (complexity > jsrlimit) return;
  1647                 super.scan(tree);
  1649             public void visitClassDef(JCClassDecl tree) {}
  1650             public void visitDoLoop(JCDoWhileLoop tree)
  1651                 { super.visitDoLoop(tree); complexity++; }
  1652             public void visitWhileLoop(JCWhileLoop tree)
  1653                 { super.visitWhileLoop(tree); complexity++; }
  1654             public void visitForLoop(JCForLoop tree)
  1655                 { super.visitForLoop(tree); complexity++; }
  1656             public void visitSwitch(JCSwitch tree)
  1657                 { super.visitSwitch(tree); complexity+=5; }
  1658             public void visitCase(JCCase tree)
  1659                 { super.visitCase(tree); complexity++; }
  1660             public void visitSynchronized(JCSynchronized tree)
  1661                 { super.visitSynchronized(tree); complexity+=6; }
  1662             public void visitTry(JCTry tree)
  1663                 { super.visitTry(tree);
  1664                   if (tree.finalizer != null) complexity+=6; }
  1665             public void visitCatch(JCCatch tree)
  1666                 { super.visitCatch(tree); complexity+=2; }
  1667             public void visitConditional(JCConditional tree)
  1668                 { super.visitConditional(tree); complexity+=2; }
  1669             public void visitIf(JCIf tree)
  1670                 { super.visitIf(tree); complexity+=2; }
  1671             // note: for break, continue, and return we don't take unwind() into account.
  1672             public void visitBreak(JCBreak tree)
  1673                 { super.visitBreak(tree); complexity+=1; }
  1674             public void visitContinue(JCContinue tree)
  1675                 { super.visitContinue(tree); complexity+=1; }
  1676             public void visitReturn(JCReturn tree)
  1677                 { super.visitReturn(tree); complexity+=1; }
  1678             public void visitThrow(JCThrow tree)
  1679                 { super.visitThrow(tree); complexity+=1; }
  1680             public void visitAssert(JCAssert tree)
  1681                 { super.visitAssert(tree); complexity+=5; }
  1682             public void visitApply(JCMethodInvocation tree)
  1683                 { super.visitApply(tree); complexity+=2; }
  1684             public void visitNewClass(JCNewClass tree)
  1685                 { scan(tree.encl); scan(tree.args); complexity+=2; }
  1686             public void visitNewArray(JCNewArray tree)
  1687                 { super.visitNewArray(tree); complexity+=5; }
  1688             public void visitAssign(JCAssign tree)
  1689                 { super.visitAssign(tree); complexity+=1; }
  1690             public void visitAssignop(JCAssignOp tree)
  1691                 { super.visitAssignop(tree); complexity+=2; }
  1692             public void visitUnary(JCUnary tree)
  1693                 { complexity+=1;
  1694                   if (tree.type.constValue() == null) super.visitUnary(tree); }
  1695             public void visitBinary(JCBinary tree)
  1696                 { complexity+=1;
  1697                   if (tree.type.constValue() == null) super.visitBinary(tree); }
  1698             public void visitTypeTest(JCInstanceOf tree)
  1699                 { super.visitTypeTest(tree); complexity+=1; }
  1700             public void visitIndexed(JCArrayAccess tree)
  1701                 { super.visitIndexed(tree); complexity+=1; }
  1702             public void visitSelect(JCFieldAccess tree)
  1703                 { super.visitSelect(tree);
  1704                   if (tree.sym.kind == VAR) complexity+=1; }
  1705             public void visitIdent(JCIdent tree) {
  1706                 if (tree.sym.kind == VAR) {
  1707                     complexity+=1;
  1708                     if (tree.type.constValue() == null &&
  1709                         tree.sym.owner.kind == TYP)
  1710                         complexity+=1;
  1713             public void visitLiteral(JCLiteral tree)
  1714                 { complexity+=1; }
  1715             public void visitTree(JCTree tree) {}
  1716             public void visitWildcard(JCWildcard tree) {
  1717                 throw new AssertionError(this.getClass().getName());
  1720         ComplexityScanner scanner = new ComplexityScanner();
  1721         tree.accept(scanner);
  1722         return scanner.complexity;
  1725     public void visitIf(JCIf tree) {
  1726         int limit = code.nextreg;
  1727         Chain thenExit = null;
  1728         CondItem c = genCond(TreeInfo.skipParens(tree.cond),
  1729                              CRT_FLOW_CONTROLLER);
  1730         Chain elseChain = c.jumpFalse();
  1731         if (!c.isFalse()) {
  1732             code.resolve(c.trueJumps);
  1733             genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
  1734             thenExit = code.branch(goto_);
  1736         if (elseChain != null) {
  1737             code.resolve(elseChain);
  1738             if (tree.elsepart != null)
  1739                 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
  1741         code.resolve(thenExit);
  1742         code.endScopes(limit);
  1745     public void visitExec(JCExpressionStatement tree) {
  1746         // Optimize x++ to ++x and x-- to --x.
  1747         JCExpression e = tree.expr;
  1748         switch (e.getTag()) {
  1749             case POSTINC:
  1750                 ((JCUnary) e).setTag(PREINC);
  1751                 break;
  1752             case POSTDEC:
  1753                 ((JCUnary) e).setTag(PREDEC);
  1754                 break;
  1756         genExpr(tree.expr, tree.expr.type).drop();
  1759     public void visitBreak(JCBreak tree) {
  1760         Env<GenContext> targetEnv = unwind(tree.target, env);
  1761         Assert.check(code.state.stacksize == 0);
  1762         targetEnv.info.addExit(code.branch(goto_));
  1763         endFinalizerGaps(env, targetEnv);
  1766     public void visitContinue(JCContinue tree) {
  1767         Env<GenContext> targetEnv = unwind(tree.target, env);
  1768         Assert.check(code.state.stacksize == 0);
  1769         targetEnv.info.addCont(code.branch(goto_));
  1770         endFinalizerGaps(env, targetEnv);
  1773     public void visitReturn(JCReturn tree) {
  1774         int limit = code.nextreg;
  1775         final Env<GenContext> targetEnv;
  1776         if (tree.expr != null) {
  1777             Item r = genExpr(tree.expr, pt).load();
  1778             if (hasFinally(env.enclMethod, env)) {
  1779                 r = makeTemp(pt);
  1780                 r.store();
  1782             targetEnv = unwind(env.enclMethod, env);
  1783             r.load();
  1784             code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
  1785         } else {
  1786             targetEnv = unwind(env.enclMethod, env);
  1787             code.emitop0(return_);
  1789         endFinalizerGaps(env, targetEnv);
  1790         code.endScopes(limit);
  1793     public void visitThrow(JCThrow tree) {
  1794         genExpr(tree.expr, tree.expr.type).load();
  1795         code.emitop0(athrow);
  1798 /* ************************************************************************
  1799  * Visitor methods for expressions
  1800  *************************************************************************/
  1802     public void visitApply(JCMethodInvocation tree) {
  1803         setTypeAnnotationPositions(tree.pos);
  1804         // Generate code for method.
  1805         Item m = genExpr(tree.meth, methodType);
  1806         // Generate code for all arguments, where the expected types are
  1807         // the parameters of the method's external type (that is, any implicit
  1808         // outer instance of a super(...) call appears as first parameter).
  1809         MethodSymbol msym = (MethodSymbol)TreeInfo.symbol(tree.meth);
  1810         genArgs(tree.args,
  1811                 msym.externalType(types).getParameterTypes());
  1812         if (!msym.isDynamic()) {
  1813             code.statBegin(tree.pos);
  1814             code.markStatBegin();
  1816         result = m.invoke();
  1819     public void visitConditional(JCConditional tree) {
  1820         Chain thenExit = null;
  1821         CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
  1822         Chain elseChain = c.jumpFalse();
  1823         if (!c.isFalse()) {
  1824             code.resolve(c.trueJumps);
  1825             int startpc = genCrt ? code.curPc() : 0;
  1826             genExpr(tree.truepart, pt).load();
  1827             code.state.forceStackTop(tree.type);
  1828             if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
  1829                                      startpc, code.curPc());
  1830             thenExit = code.branch(goto_);
  1832         if (elseChain != null) {
  1833             code.resolve(elseChain);
  1834             int startpc = genCrt ? code.curPc() : 0;
  1835             genExpr(tree.falsepart, pt).load();
  1836             code.state.forceStackTop(tree.type);
  1837             if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
  1838                                      startpc, code.curPc());
  1840         code.resolve(thenExit);
  1841         result = items.makeStackItem(pt);
  1844     private void setTypeAnnotationPositions(int treePos) {
  1845         MethodSymbol meth = code.meth;
  1846         boolean initOrClinit = code.meth.getKind() == javax.lang.model.element.ElementKind.CONSTRUCTOR
  1847                 || code.meth.getKind() == javax.lang.model.element.ElementKind.STATIC_INIT;
  1849         for (Attribute.TypeCompound ta : meth.getRawTypeAttributes()) {
  1850             if (ta.hasUnknownPosition())
  1851                 ta.tryFixPosition();
  1853             if (ta.position.matchesPos(treePos))
  1854                 ta.position.updatePosOffset(code.cp);
  1857         if (!initOrClinit)
  1858             return;
  1860         for (Attribute.TypeCompound ta : meth.owner.getRawTypeAttributes()) {
  1861             if (ta.hasUnknownPosition())
  1862                 ta.tryFixPosition();
  1864             if (ta.position.matchesPos(treePos))
  1865                 ta.position.updatePosOffset(code.cp);
  1868         ClassSymbol clazz = meth.enclClass();
  1869         for (Symbol s : new com.sun.tools.javac.model.FilteredMemberList(clazz.members())) {
  1870             if (!s.getKind().isField())
  1871                 continue;
  1873             for (Attribute.TypeCompound ta : s.getRawTypeAttributes()) {
  1874                 if (ta.hasUnknownPosition())
  1875                     ta.tryFixPosition();
  1877                 if (ta.position.matchesPos(treePos))
  1878                     ta.position.updatePosOffset(code.cp);
  1883     public void visitNewClass(JCNewClass tree) {
  1884         // Enclosing instances or anonymous classes should have been eliminated
  1885         // by now.
  1886         Assert.check(tree.encl == null && tree.def == null);
  1887         setTypeAnnotationPositions(tree.pos);
  1889         code.emitop2(new_, makeRef(tree.pos(), tree.type));
  1890         code.emitop0(dup);
  1892         // Generate code for all arguments, where the expected types are
  1893         // the parameters of the constructor's external type (that is,
  1894         // any implicit outer instance appears as first parameter).
  1895         genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
  1897         items.makeMemberItem(tree.constructor, true).invoke();
  1898         result = items.makeStackItem(tree.type);
  1901     public void visitNewArray(JCNewArray tree) {
  1902         setTypeAnnotationPositions(tree.pos);
  1904         if (tree.elems != null) {
  1905             Type elemtype = types.elemtype(tree.type);
  1906             loadIntConst(tree.elems.length());
  1907             Item arr = makeNewArray(tree.pos(), tree.type, 1);
  1908             int i = 0;
  1909             for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
  1910                 arr.duplicate();
  1911                 loadIntConst(i);
  1912                 i++;
  1913                 genExpr(l.head, elemtype).load();
  1914                 items.makeIndexedItem(elemtype).store();
  1916             result = arr;
  1917         } else {
  1918             for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
  1919                 genExpr(l.head, syms.intType).load();
  1921             result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
  1924 //where
  1925         /** Generate code to create an array with given element type and number
  1926          *  of dimensions.
  1927          */
  1928         Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
  1929             Type elemtype = types.elemtype(type);
  1930             if (types.dimensions(type) > ClassFile.MAX_DIMENSIONS) {
  1931                 log.error(pos, "limit.dimensions");
  1932                 nerrs++;
  1934             int elemcode = Code.arraycode(elemtype);
  1935             if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
  1936                 code.emitAnewarray(makeRef(pos, elemtype), type);
  1937             } else if (elemcode == 1) {
  1938                 code.emitMultianewarray(ndims, makeRef(pos, type), type);
  1939             } else {
  1940                 code.emitNewarray(elemcode, type);
  1942             return items.makeStackItem(type);
  1945     public void visitParens(JCParens tree) {
  1946         result = genExpr(tree.expr, tree.expr.type);
  1949     public void visitAssign(JCAssign tree) {
  1950         Item l = genExpr(tree.lhs, tree.lhs.type);
  1951         genExpr(tree.rhs, tree.lhs.type).load();
  1952         result = items.makeAssignItem(l);
  1955     public void visitAssignop(JCAssignOp tree) {
  1956         OperatorSymbol operator = (OperatorSymbol) tree.operator;
  1957         Item l;
  1958         if (operator.opcode == string_add) {
  1959             // Generate code to make a string buffer
  1960             makeStringBuffer(tree.pos());
  1962             // Generate code for first string, possibly save one
  1963             // copy under buffer
  1964             l = genExpr(tree.lhs, tree.lhs.type);
  1965             if (l.width() > 0) {
  1966                 code.emitop0(dup_x1 + 3 * (l.width() - 1));
  1969             // Load first string and append to buffer.
  1970             l.load();
  1971             appendString(tree.lhs);
  1973             // Append all other strings to buffer.
  1974             appendStrings(tree.rhs);
  1976             // Convert buffer to string.
  1977             bufferToString(tree.pos());
  1978         } else {
  1979             // Generate code for first expression
  1980             l = genExpr(tree.lhs, tree.lhs.type);
  1982             // If we have an increment of -32768 to +32767 of a local
  1983             // int variable we can use an incr instruction instead of
  1984             // proceeding further.
  1985             if ((tree.hasTag(PLUS_ASG) || tree.hasTag(MINUS_ASG)) &&
  1986                 l instanceof LocalItem &&
  1987                 tree.lhs.type.getTag().isSubRangeOf(INT) &&
  1988                 tree.rhs.type.getTag().isSubRangeOf(INT) &&
  1989                 tree.rhs.type.constValue() != null) {
  1990                 int ival = ((Number) tree.rhs.type.constValue()).intValue();
  1991                 if (tree.hasTag(MINUS_ASG)) ival = -ival;
  1992                 ((LocalItem)l).incr(ival);
  1993                 result = l;
  1994                 return;
  1996             // Otherwise, duplicate expression, load one copy
  1997             // and complete binary operation.
  1998             l.duplicate();
  1999             l.coerce(operator.type.getParameterTypes().head).load();
  2000             completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
  2002         result = items.makeAssignItem(l);
  2005     public void visitUnary(JCUnary tree) {
  2006         OperatorSymbol operator = (OperatorSymbol)tree.operator;
  2007         if (tree.hasTag(NOT)) {
  2008             CondItem od = genCond(tree.arg, false);
  2009             result = od.negate();
  2010         } else {
  2011             Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
  2012             switch (tree.getTag()) {
  2013             case POS:
  2014                 result = od.load();
  2015                 break;
  2016             case NEG:
  2017                 result = od.load();
  2018                 code.emitop0(operator.opcode);
  2019                 break;
  2020             case COMPL:
  2021                 result = od.load();
  2022                 emitMinusOne(od.typecode);
  2023                 code.emitop0(operator.opcode);
  2024                 break;
  2025             case PREINC: case PREDEC:
  2026                 od.duplicate();
  2027                 if (od instanceof LocalItem &&
  2028                     (operator.opcode == iadd || operator.opcode == isub)) {
  2029                     ((LocalItem)od).incr(tree.hasTag(PREINC) ? 1 : -1);
  2030                     result = od;
  2031                 } else {
  2032                     od.load();
  2033                     code.emitop0(one(od.typecode));
  2034                     code.emitop0(operator.opcode);
  2035                     // Perform narrowing primitive conversion if byte,
  2036                     // char, or short.  Fix for 4304655.
  2037                     if (od.typecode != INTcode &&
  2038                         Code.truncate(od.typecode) == INTcode)
  2039                       code.emitop0(int2byte + od.typecode - BYTEcode);
  2040                     result = items.makeAssignItem(od);
  2042                 break;
  2043             case POSTINC: case POSTDEC:
  2044                 od.duplicate();
  2045                 if (od instanceof LocalItem &&
  2046                     (operator.opcode == iadd || operator.opcode == isub)) {
  2047                     Item res = od.load();
  2048                     ((LocalItem)od).incr(tree.hasTag(POSTINC) ? 1 : -1);
  2049                     result = res;
  2050                 } else {
  2051                     Item res = od.load();
  2052                     od.stash(od.typecode);
  2053                     code.emitop0(one(od.typecode));
  2054                     code.emitop0(operator.opcode);
  2055                     // Perform narrowing primitive conversion if byte,
  2056                     // char, or short.  Fix for 4304655.
  2057                     if (od.typecode != INTcode &&
  2058                         Code.truncate(od.typecode) == INTcode)
  2059                       code.emitop0(int2byte + od.typecode - BYTEcode);
  2060                     od.store();
  2061                     result = res;
  2063                 break;
  2064             case NULLCHK:
  2065                 result = od.load();
  2066                 code.emitop0(dup);
  2067                 genNullCheck(tree.pos());
  2068                 break;
  2069             default:
  2070                 Assert.error();
  2075     /** Generate a null check from the object value at stack top. */
  2076     private void genNullCheck(DiagnosticPosition pos) {
  2077         callMethod(pos, syms.objectType, names.getClass,
  2078                    List.<Type>nil(), false);
  2079         code.emitop0(pop);
  2082     public void visitBinary(JCBinary tree) {
  2083         OperatorSymbol operator = (OperatorSymbol)tree.operator;
  2084         if (operator.opcode == string_add) {
  2085             // Create a string buffer.
  2086             makeStringBuffer(tree.pos());
  2087             // Append all strings to buffer.
  2088             appendStrings(tree);
  2089             // Convert buffer to string.
  2090             bufferToString(tree.pos());
  2091             result = items.makeStackItem(syms.stringType);
  2092         } else if (tree.hasTag(AND)) {
  2093             CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
  2094             if (!lcond.isFalse()) {
  2095                 Chain falseJumps = lcond.jumpFalse();
  2096                 code.resolve(lcond.trueJumps);
  2097                 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
  2098                 result = items.
  2099                     makeCondItem(rcond.opcode,
  2100                                  rcond.trueJumps,
  2101                                  Code.mergeChains(falseJumps,
  2102                                                   rcond.falseJumps));
  2103             } else {
  2104                 result = lcond;
  2106         } else if (tree.hasTag(OR)) {
  2107             CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
  2108             if (!lcond.isTrue()) {
  2109                 Chain trueJumps = lcond.jumpTrue();
  2110                 code.resolve(lcond.falseJumps);
  2111                 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
  2112                 result = items.
  2113                     makeCondItem(rcond.opcode,
  2114                                  Code.mergeChains(trueJumps, rcond.trueJumps),
  2115                                  rcond.falseJumps);
  2116             } else {
  2117                 result = lcond;
  2119         } else {
  2120             Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
  2121             od.load();
  2122             result = completeBinop(tree.lhs, tree.rhs, operator);
  2125 //where
  2126         /** Make a new string buffer.
  2127          */
  2128         void makeStringBuffer(DiagnosticPosition pos) {
  2129             code.emitop2(new_, makeRef(pos, stringBufferType));
  2130             code.emitop0(dup);
  2131             callMethod(
  2132                 pos, stringBufferType, names.init, List.<Type>nil(), false);
  2135         /** Append value (on tos) to string buffer (on tos - 1).
  2136          */
  2137         void appendString(JCTree tree) {
  2138             Type t = tree.type.baseType();
  2139             if (!t.isPrimitive() && t.tsym != syms.stringType.tsym) {
  2140                 t = syms.objectType;
  2142             items.makeMemberItem(getStringBufferAppend(tree, t), false).invoke();
  2144         Symbol getStringBufferAppend(JCTree tree, Type t) {
  2145             Assert.checkNull(t.constValue());
  2146             Symbol method = stringBufferAppend.get(t);
  2147             if (method == null) {
  2148                 method = rs.resolveInternalMethod(tree.pos(),
  2149                                                   attrEnv,
  2150                                                   stringBufferType,
  2151                                                   names.append,
  2152                                                   List.of(t),
  2153                                                   null);
  2154                 stringBufferAppend.put(t, method);
  2156             return method;
  2159         /** Add all strings in tree to string buffer.
  2160          */
  2161         void appendStrings(JCTree tree) {
  2162             tree = TreeInfo.skipParens(tree);
  2163             if (tree.hasTag(PLUS) && tree.type.constValue() == null) {
  2164                 JCBinary op = (JCBinary) tree;
  2165                 if (op.operator.kind == MTH &&
  2166                     ((OperatorSymbol) op.operator).opcode == string_add) {
  2167                     appendStrings(op.lhs);
  2168                     appendStrings(op.rhs);
  2169                     return;
  2172             genExpr(tree, tree.type).load();
  2173             appendString(tree);
  2176         /** Convert string buffer on tos to string.
  2177          */
  2178         void bufferToString(DiagnosticPosition pos) {
  2179             callMethod(
  2180                 pos,
  2181                 stringBufferType,
  2182                 names.toString,
  2183                 List.<Type>nil(),
  2184                 false);
  2187         /** Complete generating code for operation, with left operand
  2188          *  already on stack.
  2189          *  @param lhs       The tree representing the left operand.
  2190          *  @param rhs       The tree representing the right operand.
  2191          *  @param operator  The operator symbol.
  2192          */
  2193         Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
  2194             MethodType optype = (MethodType)operator.type;
  2195             int opcode = operator.opcode;
  2196             if (opcode >= if_icmpeq && opcode <= if_icmple &&
  2197                 rhs.type.constValue() instanceof Number &&
  2198                 ((Number) rhs.type.constValue()).intValue() == 0) {
  2199                 opcode = opcode + (ifeq - if_icmpeq);
  2200             } else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
  2201                        TreeInfo.isNull(rhs)) {
  2202                 opcode = opcode + (if_acmp_null - if_acmpeq);
  2203             } else {
  2204                 // The expected type of the right operand is
  2205                 // the second parameter type of the operator, except for
  2206                 // shifts with long shiftcount, where we convert the opcode
  2207                 // to a short shift and the expected type to int.
  2208                 Type rtype = operator.erasure(types).getParameterTypes().tail.head;
  2209                 if (opcode >= ishll && opcode <= lushrl) {
  2210                     opcode = opcode + (ishl - ishll);
  2211                     rtype = syms.intType;
  2213                 // Generate code for right operand and load.
  2214                 genExpr(rhs, rtype).load();
  2215                 // If there are two consecutive opcode instructions,
  2216                 // emit the first now.
  2217                 if (opcode >= (1 << preShift)) {
  2218                     code.emitop0(opcode >> preShift);
  2219                     opcode = opcode & 0xFF;
  2222             if (opcode >= ifeq && opcode <= if_acmpne ||
  2223                 opcode == if_acmp_null || opcode == if_acmp_nonnull) {
  2224                 return items.makeCondItem(opcode);
  2225             } else {
  2226                 code.emitop0(opcode);
  2227                 return items.makeStackItem(optype.restype);
  2231     public void visitTypeCast(JCTypeCast tree) {
  2232         setTypeAnnotationPositions(tree.pos);
  2233         result = genExpr(tree.expr, tree.clazz.type).load();
  2234         // Additional code is only needed if we cast to a reference type
  2235         // which is not statically a supertype of the expression's type.
  2236         // For basic types, the coerce(...) in genExpr(...) will do
  2237         // the conversion.
  2238         if (!tree.clazz.type.isPrimitive() &&
  2239             types.asSuper(tree.expr.type, tree.clazz.type.tsym) == null) {
  2240             code.emitop2(checkcast, makeRef(tree.pos(), tree.clazz.type));
  2244     public void visitWildcard(JCWildcard tree) {
  2245         throw new AssertionError(this.getClass().getName());
  2248     public void visitTypeTest(JCInstanceOf tree) {
  2249         setTypeAnnotationPositions(tree.pos);
  2250         genExpr(tree.expr, tree.expr.type).load();
  2251         code.emitop2(instanceof_, makeRef(tree.pos(), tree.clazz.type));
  2252         result = items.makeStackItem(syms.booleanType);
  2255     public void visitIndexed(JCArrayAccess tree) {
  2256         genExpr(tree.indexed, tree.indexed.type).load();
  2257         genExpr(tree.index, syms.intType).load();
  2258         result = items.makeIndexedItem(tree.type);
  2261     public void visitIdent(JCIdent tree) {
  2262         Symbol sym = tree.sym;
  2263         if (tree.name == names._this || tree.name == names._super) {
  2264             Item res = tree.name == names._this
  2265                 ? items.makeThisItem()
  2266                 : items.makeSuperItem();
  2267             if (sym.kind == MTH) {
  2268                 // Generate code to address the constructor.
  2269                 res.load();
  2270                 res = items.makeMemberItem(sym, true);
  2272             result = res;
  2273         } else if (sym.kind == VAR && sym.owner.kind == MTH) {
  2274             result = items.makeLocalItem((VarSymbol)sym);
  2275         } else if (isInvokeDynamic(sym)) {
  2276             result = items.makeDynamicItem(sym);
  2277         } else if ((sym.flags() & STATIC) != 0) {
  2278             if (!isAccessSuper(env.enclMethod))
  2279                 sym = binaryQualifier(sym, env.enclClass.type);
  2280             result = items.makeStaticItem(sym);
  2281         } else {
  2282             items.makeThisItem().load();
  2283             sym = binaryQualifier(sym, env.enclClass.type);
  2284             result = items.makeMemberItem(sym, (sym.flags() & PRIVATE) != 0);
  2288     public void visitSelect(JCFieldAccess tree) {
  2289         Symbol sym = tree.sym;
  2291         if (tree.name == names._class) {
  2292             Assert.check(target.hasClassLiterals());
  2293             code.emitLdc(makeRef(tree.pos(), tree.selected.type));
  2294             result = items.makeStackItem(pt);
  2295             return;
  2298         Symbol ssym = TreeInfo.symbol(tree.selected);
  2300         // Are we selecting via super?
  2301         boolean selectSuper =
  2302             ssym != null && (ssym.kind == TYP || ssym.name == names._super);
  2304         // Are we accessing a member of the superclass in an access method
  2305         // resulting from a qualified super?
  2306         boolean accessSuper = isAccessSuper(env.enclMethod);
  2308         Item base = (selectSuper)
  2309             ? items.makeSuperItem()
  2310             : genExpr(tree.selected, tree.selected.type);
  2312         if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
  2313             // We are seeing a variable that is constant but its selecting
  2314             // expression is not.
  2315             if ((sym.flags() & STATIC) != 0) {
  2316                 if (!selectSuper && (ssym == null || ssym.kind != TYP))
  2317                     base = base.load();
  2318                 base.drop();
  2319             } else {
  2320                 base.load();
  2321                 genNullCheck(tree.selected.pos());
  2323             result = items.
  2324                 makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
  2325         } else {
  2326             if (isInvokeDynamic(sym)) {
  2327                 result = items.makeDynamicItem(sym);
  2328                 return;
  2329             } else if (!accessSuper) {
  2330                 sym = binaryQualifier(sym, tree.selected.type);
  2332             if ((sym.flags() & STATIC) != 0) {
  2333                 if (!selectSuper && (ssym == null || ssym.kind != TYP))
  2334                     base = base.load();
  2335                 base.drop();
  2336                 result = items.makeStaticItem(sym);
  2337             } else {
  2338                 base.load();
  2339                 if (sym == syms.lengthVar) {
  2340                     code.emitop0(arraylength);
  2341                     result = items.makeStackItem(syms.intType);
  2342                 } else {
  2343                     result = items.
  2344                         makeMemberItem(sym,
  2345                                        (sym.flags() & PRIVATE) != 0 ||
  2346                                        selectSuper || accessSuper);
  2352     public boolean isInvokeDynamic(Symbol sym) {
  2353         return sym.kind == MTH && ((MethodSymbol)sym).isDynamic();
  2356     public void visitLiteral(JCLiteral tree) {
  2357         if (tree.type.hasTag(BOT)) {
  2358             code.emitop0(aconst_null);
  2359             if (types.dimensions(pt) > 1) {
  2360                 code.emitop2(checkcast, makeRef(tree.pos(), pt));
  2361                 result = items.makeStackItem(pt);
  2362             } else {
  2363                 result = items.makeStackItem(tree.type);
  2366         else
  2367             result = items.makeImmediateItem(tree.type, tree.value);
  2370     public void visitLetExpr(LetExpr tree) {
  2371         int limit = code.nextreg;
  2372         genStats(tree.defs, env);
  2373         result = genExpr(tree.expr, tree.expr.type).load();
  2374         code.endScopes(limit);
  2377     private void generateReferencesToPrunedTree(ClassSymbol classSymbol, Pool pool) {
  2378         List<JCTree> prunedInfo = lower.prunedTree.get(classSymbol);
  2379         if (prunedInfo != null) {
  2380             for (JCTree prunedTree: prunedInfo) {
  2381                 prunedTree.accept(classReferenceVisitor);
  2386 /* ************************************************************************
  2387  * main method
  2388  *************************************************************************/
  2390     /** Generate code for a class definition.
  2391      *  @param env   The attribution environment that belongs to the
  2392      *               outermost class containing this class definition.
  2393      *               We need this for resolving some additional symbols.
  2394      *  @param cdef  The tree representing the class definition.
  2395      *  @return      True if code is generated with no errors.
  2396      */
  2397     public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
  2398         try {
  2399             attrEnv = env;
  2400             ClassSymbol c = cdef.sym;
  2401             this.toplevel = env.toplevel;
  2402             this.endPosTable = toplevel.endPositions;
  2403             // If this is a class definition requiring Miranda methods,
  2404             // add them.
  2405             if (generateIproxies &&
  2406                 (c.flags() & (INTERFACE|ABSTRACT)) == ABSTRACT
  2407                 && !allowGenerics // no Miranda methods available with generics
  2409                 implementInterfaceMethods(c);
  2410             cdef.defs = normalizeDefs(cdef.defs, c);
  2411             c.pool = pool;
  2412             pool.reset();
  2413             generateReferencesToPrunedTree(c, pool);
  2414             Env<GenContext> localEnv =
  2415                 new Env<GenContext>(cdef, new GenContext());
  2416             localEnv.toplevel = env.toplevel;
  2417             localEnv.enclClass = cdef;
  2418             for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
  2419                 genDef(l.head, localEnv);
  2421             if (pool.numEntries() > Pool.MAX_ENTRIES) {
  2422                 log.error(cdef.pos(), "limit.pool");
  2423                 nerrs++;
  2425             if (nerrs != 0) {
  2426                 // if errors, discard code
  2427                 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
  2428                     if (l.head.hasTag(METHODDEF))
  2429                         ((JCMethodDecl) l.head).sym.code = null;
  2432             cdef.defs = List.nil(); // discard trees
  2433             return nerrs == 0;
  2434         } finally {
  2435             // note: this method does NOT support recursion.
  2436             attrEnv = null;
  2437             this.env = null;
  2438             toplevel = null;
  2439             endPosTable = null;
  2440             nerrs = 0;
  2444 /* ************************************************************************
  2445  * Auxiliary classes
  2446  *************************************************************************/
  2448     /** An abstract class for finalizer generation.
  2449      */
  2450     abstract class GenFinalizer {
  2451         /** Generate code to clean up when unwinding. */
  2452         abstract void gen();
  2454         /** Generate code to clean up at last. */
  2455         abstract void genLast();
  2457         /** Does this finalizer have some nontrivial cleanup to perform? */
  2458         boolean hasFinalizer() { return true; }
  2461     /** code generation contexts,
  2462      *  to be used as type parameter for environments.
  2463      */
  2464     static class GenContext {
  2466         /** A chain for all unresolved jumps that exit the current environment.
  2467          */
  2468         Chain exit = null;
  2470         /** A chain for all unresolved jumps that continue in the
  2471          *  current environment.
  2472          */
  2473         Chain cont = null;
  2475         /** A closure that generates the finalizer of the current environment.
  2476          *  Only set for Synchronized and Try contexts.
  2477          */
  2478         GenFinalizer finalize = null;
  2480         /** Is this a switch statement?  If so, allocate registers
  2481          * even when the variable declaration is unreachable.
  2482          */
  2483         boolean isSwitch = false;
  2485         /** A list buffer containing all gaps in the finalizer range,
  2486          *  where a catch all exception should not apply.
  2487          */
  2488         ListBuffer<Integer> gaps = null;
  2490         /** Add given chain to exit chain.
  2491          */
  2492         void addExit(Chain c)  {
  2493             exit = Code.mergeChains(c, exit);
  2496         /** Add given chain to cont chain.
  2497          */
  2498         void addCont(Chain c) {
  2499             cont = Code.mergeChains(c, cont);

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