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

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  80     private final StringConcat concat;
  81 
  82     /** Format of stackmap tables to be generated. */
  83     private final Code.StackMapFormat stackMap;
  84 
  85     /** A type that serves as the expected type for all method expressions.
  86      */
  87     private final Type methodType;
  88 
  89     public static Gen instance(Context context) {
  90         Gen instance = context.get(genKey);
  91         if (instance == null)
  92             instance = new Gen(context);
  93         return instance;
  94     }
  95 
  96     /** Constant pool writer, set by genClass.
  97      */
  98     final PoolWriter poolWriter;
  99 


 100     @SuppressWarnings("this-escape")
 101     protected Gen(Context context) {
 102         context.put(genKey, this);
 103 
 104         names = Names.instance(context);
 105         log = Log.instance(context);
 106         syms = Symtab.instance(context);
 107         chk = Check.instance(context);
 108         rs = Resolve.instance(context);
 109         make = TreeMaker.instance(context);
 110         target = Target.instance(context);
 111         types = Types.instance(context);
 112         concat = StringConcat.instance(context);
 113 
 114         methodType = new MethodType(null, null, null, syms.methodClass);
 115         accessDollar = "access" + target.syntheticNameChar();
 116         lower = Lower.instance(context);
 117 
 118         Options options = Options.instance(context);
 119         lineDebugInfo =
 120             options.isUnset(G_CUSTOM) ||
 121             options.isSet(G_CUSTOM, "lines");
 122         varDebugInfo =
 123             options.isUnset(G_CUSTOM)
 124             ? options.isSet(G)
 125             : options.isSet(G_CUSTOM, "vars");
 126         genCrt = options.isSet(XJCOV);
 127         debugCode = options.isSet("debug.code");
 128         disableVirtualizedPrivateInvoke = options.isSet("disableVirtualizedPrivateInvoke");
 129         poolWriter = new PoolWriter(types, names);

 130 
 131         // ignore cldc because we cannot have both stackmap formats
 132         this.stackMap = StackMapFormat.JSR202;
 133         annotate = Annotate.instance(context);
 134         qualifiedSymbolCache = new HashMap<>();




 135     }
 136 
 137     /** Switches
 138      */
 139     private final boolean lineDebugInfo;
 140     private final boolean varDebugInfo;
 141     private final boolean genCrt;
 142     private final boolean debugCode;
 143     private boolean disableVirtualizedPrivateInvoke;

 144 
 145     /** Code buffer, set by genMethod.
 146      */
 147     private Code code;
 148 
 149     /** Items structure, set by genMethod.
 150      */
 151     private Items items;
 152 
 153     /** Environment for symbol lookup, set by genClass
 154      */
 155     private Env<AttrContext> attrEnv;
 156 
 157     /** The top level tree.
 158      */
 159     private JCCompilationUnit toplevel;
 160 
 161     /** The number of code-gen errors in this class.
 162      */
 163     private int nerrs = 0;

 407     boolean hasFinally(JCTree target, Env<GenContext> env) {
 408         while (env.tree != target) {
 409             if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
 410                 return true;
 411             env = env.next;
 412         }
 413         return false;
 414     }
 415 
 416 /* ************************************************************************
 417  * Normalizing class-members.
 418  *************************************************************************/
 419 
 420     /** Distribute member initializer code into constructors and {@code <clinit>}
 421      *  method.
 422      *  @param defs         The list of class member declarations.
 423      *  @param c            The enclosing class.
 424      */
 425     List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
 426         ListBuffer<JCStatement> initCode = new ListBuffer<>();


 427         ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<>();
 428         ListBuffer<JCStatement> clinitCode = new ListBuffer<>();
 429         ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<>();
 430         ListBuffer<JCTree> methodDefs = new ListBuffer<>();
 431         // Sort definitions into three listbuffers:
 432         //  - initCode for instance initializers
 433         //  - clinitCode for class initializers
 434         //  - methodDefs for method definitions
 435         for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
 436             JCTree def = l.head;
 437             switch (def.getTag()) {
 438             case BLOCK:
 439                 JCBlock block = (JCBlock)def;
 440                 if ((block.flags & STATIC) != 0)
 441                     clinitCode.append(block);
 442                 else if ((block.flags & SYNTHETIC) == 0)
 443                     initCode.append(block);





 444                 break;
 445             case METHODDEF:
 446                 methodDefs.append(def);
 447                 break;
 448             case VARDEF:
 449                 JCVariableDecl vdef = (JCVariableDecl) def;
 450                 VarSymbol sym = vdef.sym;
 451                 checkDimension(vdef.pos(), sym.type);
 452                 if (vdef.init != null) {
 453                     if ((sym.flags() & STATIC) == 0) {
 454                         // Always initialize instance variables.
 455                         JCStatement init = make.at(vdef.pos()).
 456                             Assignment(sym, vdef.init);
 457                         initCode.append(init);
 458                         endPosTable.replaceTree(vdef, init);
 459                         initTAs.addAll(getAndRemoveNonFieldTAs(sym));
 460                     } else if (sym.getConstValue() == null) {
 461                         // Initialize class (static) variables only if
 462                         // they are not compile-time constants.
 463                         JCStatement init = make.at(vdef.pos).
 464                             Assignment(sym, vdef.init);
 465                         clinitCode.append(init);
 466                         endPosTable.replaceTree(vdef, init);
 467                         clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
 468                     } else {
 469                         checkStringConstant(vdef.init.pos(), sym.getConstValue());
 470                         /* if the init contains a reference to an external class, add it to the
 471                          * constant's pool
 472                          */
 473                         vdef.init.accept(classReferenceVisitor);
 474                     }
 475                 }
 476                 break;
 477             default:
 478                 Assert.error();
 479             }
 480         }
 481         // Insert any instance initializers into all constructors.
 482         if (initCode.length() != 0) {
 483             List<JCStatement> inits = initCode.toList();
 484             initTAs.addAll(c.getInitTypeAttributes());
 485             List<Attribute.TypeCompound> initTAlist = initTAs.toList();
 486             for (JCTree t : methodDefs) {
 487                 normalizeMethod((JCMethodDecl)t, inits, initTAlist);
 488             }
 489         }
 490         // If there are class initializers, create a <clinit> method
 491         // that contains them as its body.
 492         if (clinitCode.length() != 0) {
 493             MethodSymbol clinit = new MethodSymbol(
 494                 STATIC | (c.flags() & STRICTFP),
 495                 names.clinit,
 496                 new MethodType(
 497                     List.nil(), syms.voidType,
 498                     List.nil(), syms.methodClass),
 499                 c);
 500             c.members().enter(clinit);
 501             List<JCStatement> clinitStats = clinitCode.toList();
 502             JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
 503             block.bracePos = TreeInfo.endPos(clinitStats.last());
 504             methodDefs.append(make.MethodDef(clinit, block));
 505 
 506             if (!clinitTAs.isEmpty())
 507                 clinit.appendUniqueTypeAttributes(clinitTAs.toList());

 530 
 531     /** Check a constant value and report if it is a string that is
 532      *  too large.
 533      */
 534     private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
 535         if (nerrs != 0 || // only complain about a long string once
 536             constValue == null ||
 537             !(constValue instanceof String str) ||
 538             str.length() < PoolWriter.MAX_STRING_LENGTH)
 539             return;
 540         log.error(pos, Errors.LimitString);
 541         nerrs++;
 542     }
 543 
 544     /** Insert instance initializer code into constructors prior to the super() call.
 545      *  @param md        The tree potentially representing a
 546      *                   constructor's definition.
 547      *  @param initCode  The list of instance initializer statements.
 548      *  @param initTAs  Type annotations from the initializer expression.
 549      */
 550     void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<TypeCompound> initTAs) {
 551         if (TreeInfo.isConstructor(md) && TreeInfo.hasConstructorCall(md, names._super)) {
 552             // We are seeing a constructor that has a super() call.
 553             // Find the super() invocation and append the given initializer code.
 554             TreeInfo.mapSuperCalls(md.body, supercall -> make.Block(0, initCode.prepend(supercall)));






 555 
 556             if (md.body.bracePos == Position.NOPOS)
 557                 md.body.bracePos = TreeInfo.endPos(md.body.stats.last());
 558 
 559             md.sym.appendUniqueTypeAttributes(initTAs);
 560         }
 561     }
 562 


































 563 /* ************************************************************************
 564  * Traversal methods
 565  *************************************************************************/
 566 
 567     /** Visitor argument: The current environment.
 568      */
 569     Env<GenContext> env;
 570 
 571     /** Visitor argument: The expected type (prototype).
 572      */
 573     Type pt;
 574 
 575     /** Visitor result: The item representing the computed value.
 576      */
 577     Item result;
 578 
 579     /** Visitor method: generate code for a definition, catching and reporting
 580      *  any completion failures.
 581      *  @param tree    The definition to be visited.
 582      *  @param env     The environment current at the definition.

 939             // Count up extra parameters
 940             if (meth.isConstructor()) {
 941                 extras++;
 942                 if (meth.enclClass().isInner() &&
 943                     !meth.enclClass().isStatic()) {
 944                     extras++;
 945                 }
 946             } else if ((tree.mods.flags & STATIC) == 0) {
 947                 extras++;
 948             }
 949             //      System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
 950             if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
 951                 ClassFile.MAX_PARAMETERS) {
 952                 log.error(tree.pos(), Errors.LimitParameters);
 953                 nerrs++;
 954             }
 955 
 956             else if (tree.body != null) {
 957                 // Create a new code structure and initialize it.
 958                 int startpcCrt = initCode(tree, env, fatcode);





 959 
 960                 try {
 961                     genStat(tree.body, env);
 962                 } catch (CodeSizeOverflow e) {
 963                     // Failed due to code limit, try again with jsr/ret
 964                     startpcCrt = initCode(tree, env, fatcode);
 965                     genStat(tree.body, env);


 966                 }
 967 
 968                 if (code.state.stacksize != 0) {
 969                     log.error(tree.body.pos(), Errors.StackSimError(tree.sym));
 970                     throw new AssertionError();
 971                 }
 972 
 973                 // If last statement could complete normally, insert a
 974                 // return at the end.
 975                 if (code.isAlive()) {
 976                     code.statBegin(TreeInfo.endPos(tree.body));
 977                     if (env.enclMethod == null ||
 978                         env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
 979                         code.emitop0(return_);
 980                     } else {
 981                         // sometime dead code seems alive (4415991);
 982                         // generate a small loop instead
 983                         int startpc = code.entryPoint();
 984                         CondItem c = items.makeCondItem(goto_);
 985                         code.resolve(c.jumpTrue(), startpc);

1014 
1015                 // Fill in type annotation positions for exception parameters
1016                 code.fillExceptionParameterPositions();
1017             }
1018         }
1019 
1020         private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
1021             MethodSymbol meth = tree.sym;
1022 
1023             // Create a new code structure.
1024             meth.code = code = new Code(meth,
1025                                         fatcode,
1026                                         lineDebugInfo ? toplevel.lineMap : null,
1027                                         varDebugInfo,
1028                                         stackMap,
1029                                         debugCode,
1030                                         genCrt ? new CRTable(tree, env.toplevel.endPositions)
1031                                                : null,
1032                                         syms,
1033                                         types,
1034                                         poolWriter);

1035             items = new Items(poolWriter, code, syms, types);
1036             if (code.debugCode) {
1037                 System.err.println(meth + " for body " + tree);
1038             }
1039 
1040             // If method is not static, create a new local variable address
1041             // for `this'.
1042             if ((tree.mods.flags & STATIC) == 0) {
1043                 Type selfType = meth.owner.type;
1044                 if (meth.isConstructor() && selfType != syms.objectType)
1045                     selfType = UninitializedType.uninitializedThis(selfType);
1046                 code.setDefined(
1047                         code.newLocal(
1048                             new VarSymbol(FINAL, names._this, selfType, meth.owner)));
1049             }
1050 
1051             // Mark all parameters as defined from the beginning of
1052             // the method.
1053             for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1054                 checkDimension(l.head.pos(), l.head.sym.type);

1150     public void visitForLoop(JCForLoop tree) {
1151         int limit = code.nextreg;
1152         genStats(tree.init, env);
1153         genLoop(tree, tree.body, tree.cond, tree.step, true);
1154         code.endScopes(limit);
1155     }
1156     //where
1157         /** Generate code for a loop.
1158          *  @param loop       The tree representing the loop.
1159          *  @param body       The loop's body.
1160          *  @param cond       The loop's controlling condition.
1161          *  @param step       "Step" statements to be inserted at end of
1162          *                    each iteration.
1163          *  @param testFirst  True if the loop test belongs before the body.
1164          */
1165         private void genLoop(JCStatement loop,
1166                              JCStatement body,
1167                              JCExpression cond,
1168                              List<JCExpressionStatement> step,
1169                              boolean testFirst) {













1170             Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1171             int startpc = code.entryPoint();
1172             if (testFirst) { //while or for loop
1173                 CondItem c;
1174                 if (cond != null) {
1175                     code.statBegin(cond.pos);
1176                     Assert.check(code.isStatementStart());
1177                     c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1178                 } else {
1179                     c = items.makeCondItem(goto_);
1180                 }
1181                 Chain loopDone = c.jumpFalse();
1182                 code.resolve(c.trueJumps);
1183                 Assert.check(code.isStatementStart());
1184                 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1185                 code.resolve(loopEnv.info.cont);
1186                 genStats(step, loopEnv);
1187                 code.resolve(code.branch(goto_), startpc);
1188                 code.resolve(loopDone);
1189             } else {

1208         }
1209 
1210     public void visitForeachLoop(JCEnhancedForLoop tree) {
1211         throw new AssertionError(); // should have been removed by Lower.
1212     }
1213 
1214     public void visitLabelled(JCLabeledStatement tree) {
1215         Env<GenContext> localEnv = env.dup(tree, new GenContext());
1216         genStat(tree.body, localEnv, CRT_STATEMENT);
1217         code.resolve(localEnv.info.exit);
1218     }
1219 
1220     public void visitSwitch(JCSwitch tree) {
1221         handleSwitch(tree, tree.selector, tree.cases, tree.patternSwitch);
1222     }
1223 
1224     @Override
1225     public void visitSwitchExpression(JCSwitchExpression tree) {
1226         code.resolvePending();
1227         boolean prevInCondSwitchExpression = inCondSwitchExpression;

1228         try {
1229             inCondSwitchExpression = false;
1230             doHandleSwitchExpression(tree);
1231         } finally {
1232             inCondSwitchExpression = prevInCondSwitchExpression;

1233         }
1234         result = items.makeStackItem(pt);
1235     }
1236 
1237     private void doHandleSwitchExpression(JCSwitchExpression tree) {
1238         List<LocalItem> prevStackBeforeSwitchExpression = stackBeforeSwitchExpression;
1239         LocalItem prevSwitchResult = switchResult;
1240         int limit = code.nextreg;
1241         try {
1242             stackBeforeSwitchExpression = List.nil();
1243             switchResult = null;
1244             if (hasTry(tree)) {
1245                 //if the switch expression contains try-catch, the catch handlers need to have
1246                 //an empty stack. So stash whole stack to local variables, and restore it before
1247                 //breaks:
1248                 while (code.state.stacksize > 0) {
1249                     Type type = code.state.peek();
1250                     Name varName = names.fromString(target.syntheticNameChar() +
1251                                                     "stack" +
1252                                                     target.syntheticNameChar() +

1288                     hasTry = true;
1289                 }
1290 
1291                 @Override
1292                 public void visitClassDef(JCClassDecl tree) {
1293                 }
1294 
1295                 @Override
1296                 public void visitLambda(JCLambda tree) {
1297                 }
1298             };
1299 
1300             HasTryScanner hasTryScanner = new HasTryScanner();
1301 
1302             hasTryScanner.scan(tree);
1303             return hasTryScanner.hasTry;
1304         }
1305 
1306     private void handleSwitch(JCTree swtch, JCExpression selector, List<JCCase> cases,
1307                               boolean patternSwitch) {










1308         int limit = code.nextreg;
1309         Assert.check(!selector.type.hasTag(CLASS));
1310         int switchStart = patternSwitch ? code.entryPoint() : -1;
1311         int startpcCrt = genCrt ? code.curCP() : 0;
1312         Assert.check(code.isStatementStart());
1313         Item sel = genExpr(selector, syms.intType);
1314         if (cases.isEmpty()) {
1315             // We are seeing:  switch <sel> {}
1316             sel.load().drop();
1317             if (genCrt)
1318                 code.crt.put(TreeInfo.skipParens(selector),
1319                              CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1320         } else {
1321             // We are seeing a nonempty switch.
1322             sel.load();
1323             if (genCrt)
1324                 code.crt.put(TreeInfo.skipParens(selector),
1325                              CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1326             Env<GenContext> switchEnv = env.dup(swtch, new GenContext());
1327             switchEnv.info.isSwitch = true;
1328 
1329             // Compute number of labels and minimum and maximum label values.
1330             // For each case, store its label in an array.
1331             int lo = Integer.MAX_VALUE;  // minimum label.
1332             int hi = Integer.MIN_VALUE;  // maximum label.
1333             int nlabels = 0;               // number of labels.
1334 
1335             int[] labels = new int[cases.length()];  // the label array.
1336             int defaultIndex = -1;     // the index of the default clause.
1337 
1338             List<JCCase> l = cases;
1339             for (int i = 0; i < labels.length; i++) {
1340                 if (l.head.labels.head instanceof JCConstantCaseLabel constLabel) {
1341                     Assert.check(l.head.labels.size() == 1);
1342                     int val = ((Number) constLabel.expr.type.constValue()).intValue();
1343                     labels[i] = val;
1344                     if (val < lo) lo = val;
1345                     if (hi < val) hi = val;
1346                     nlabels++;
1347                 } else {
1348                     Assert.check(defaultIndex == -1);
1349                     defaultIndex = i;
1350                 }
1351                 l = l.tail;
1352             }
1353 
1354             // Determine whether to issue a tableswitch or a lookupswitch
1355             // instruction.
1356             long table_space_cost = 4 + ((long) hi - lo + 1); // words
1357             long table_time_cost = 3; // comparisons
1358             long lookup_space_cost = 3 + 2 * (long) nlabels;
1359             long lookup_time_cost = nlabels;
1360             int opcode =
1361                 nlabels > 0 &&
1362                 table_space_cost + 3 * table_time_cost <=
1363                 lookup_space_cost + 3 * lookup_time_cost
1364                 ?
1365                 tableswitch : lookupswitch;
1366 
1367             int startpc = code.curCP();    // the position of the selector operation
1368             code.emitop0(opcode);
1369             code.align(4);
1370             int tableBase = code.curCP();  // the start of the jump table
1371             int[] offsets = null;          // a table of offsets for a lookupswitch
1372             code.emit4(-1);                // leave space for default offset
1373             if (opcode == tableswitch) {
1374                 code.emit4(lo);            // minimum label
1375                 code.emit4(hi);            // maximum label
1376                 for (long i = lo; i <= hi; i++) {  // leave space for jump table
1377                     code.emit4(-1);
1378                 }
1379             } else {
1380                 code.emit4(nlabels);    // number of labels
1381                 for (int i = 0; i < nlabels; i++) {
1382                     code.emit4(-1); code.emit4(-1); // leave space for lookup table
1383                 }
1384                 offsets = new int[labels.length];
1385             }
1386             Code.State stateSwitch = code.state.dup();
1387             code.markDead();
1388 
1389             // For each case do:
1390             l = cases;
1391             for (int i = 0; i < labels.length; i++) {
1392                 JCCase c = l.head;
1393                 l = l.tail;
1394 
1395                 int pc = code.entryPoint(stateSwitch);
1396                 // Insert offset directly into code or else into the
1397                 // offsets table.
1398                 if (i != defaultIndex) {
1399                     if (opcode == tableswitch) {
1400                         code.put4(
1401                             tableBase + 4 * (labels[i] - lo + 3),
1402                             pc - startpc);
1403                     } else {
1404                         offsets[i] = pc - startpc;
1405                     }
1406                 } else {
1407                     code.put4(tableBase, pc - startpc);
1408                 }
1409 
1410                 // Generate code for the statements in this case.
1411                 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1412             }
1413 
1414             if (switchEnv.info.cont != null) {
1415                 Assert.check(patternSwitch);
1416                 code.resolve(switchEnv.info.cont, switchStart);
1417             }
1418 
1419             // Resolve all breaks.
1420             code.resolve(switchEnv.info.exit);
1421 
1422             // If we have not set the default offset, we do so now.

1432                     if (code.get4(t) == -1)
1433                         code.put4(t, defaultOffset);
1434                 }
1435             } else {
1436                 // Sort non-default offsets and copy into lookup table.
1437                 if (defaultIndex >= 0)
1438                     for (int i = defaultIndex; i < labels.length - 1; i++) {
1439                         labels[i] = labels[i+1];
1440                         offsets[i] = offsets[i+1];
1441                     }
1442                 if (nlabels > 0)
1443                     qsort2(labels, offsets, 0, nlabels - 1);
1444                 for (int i = 0; i < nlabels; i++) {
1445                     int caseidx = tableBase + 8 * (i + 1);
1446                     code.put4(caseidx, labels[i]);
1447                     code.put4(caseidx + 4, offsets[i]);
1448                 }
1449             }
1450 
1451             if (swtch instanceof JCSwitchExpression) {
1452                  // Emit line position for the end of a switch expression
1453                  code.statBegin(TreeInfo.endPos(swtch));
1454             }
1455         }
1456         code.endScopes(limit);
1457     }
1458 //where
1459         /** Sort (int) arrays of keys and values
1460          */
1461        static void qsort2(int[] keys, int[] values, int lo, int hi) {
1462             int i = lo;
1463             int j = hi;
1464             int pivot = keys[(i+j)/2];
1465             do {
1466                 while (keys[i] < pivot) i++;
1467                 while (pivot < keys[j]) j--;
1468                 if (i <= j) {
1469                     int temp1 = keys[i];
1470                     keys[i] = keys[j];
1471                     keys[j] = temp1;
1472                     int temp2 = values[i];
1473                     values[i] = values[j];

1536             @Override
1537             void afterBody() {
1538                 if (tree.finalizer != null && (tree.finalizer.flags & BODY_ONLY_FINALIZE) != 0) {
1539                     //for body-only finally, remove the GenFinalizer after try body
1540                     //so that the finally is not generated to catch bodies:
1541                     tryEnv.info.finalize = null;
1542                 }
1543             }
1544 
1545         };
1546         tryEnv.info.gaps = new ListBuffer<>();
1547         genTry(tree.body, tree.catchers, tryEnv);
1548     }
1549     //where
1550         /** Generate code for a try or synchronized statement
1551          *  @param body      The body of the try or synchronized statement.
1552          *  @param catchers  The list of catch clauses.
1553          *  @param env       The current environment of the body.
1554          */
1555         void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {









1556             int limit = code.nextreg;
1557             int startpc = code.curCP();
1558             Code.State stateTry = code.state.dup();
1559             genStat(body, env, CRT_BLOCK);
1560             int endpc = code.curCP();
1561             List<Integer> gaps = env.info.gaps.toList();
1562             code.statBegin(TreeInfo.endPos(body));
1563             genFinalizer(env);
1564             code.statBegin(TreeInfo.endPos(env.tree));
1565             Chain exitChain;
1566             boolean actualTry = env.tree.hasTag(TRY);
1567             if (startpc == endpc && actualTry) {
1568                 exitChain = code.branch(dontgoto);
1569             } else {
1570                 exitChain = code.branch(goto_);
1571             }
1572             endFinalizerGap(env);
1573             env.info.finalize.afterBody();
1574             boolean hasFinalizer =
1575                 env.info.finalize != null &&
1576                 env.info.finalize.hasFinalizer();
1577             if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1578                 // start off with exception on stack
1579                 code.entryPoint(stateTry, l.head.param.sym.type);
1580                 genCatch(l.head, env, startpc, endpc, gaps);
1581                 genFinalizer(env);
1582                 if (hasFinalizer || l.tail.nonEmpty()) {
1583                     code.statBegin(TreeInfo.endPos(env.tree));
1584                     exitChain = Code.mergeChains(exitChain,
1585                                                  code.branch(goto_));
1586                 }
1587                 endFinalizerGap(env);
1588             }
1589             if (hasFinalizer && (startpc != endpc || !actualTry)) {
1590                 // Create a new register segment to avoid allocating
1591                 // the same variables in finalizers and other statements.
1592                 code.newRegSegment();
1593 
1594                 // Add a catch-all clause.
1595 
1596                 // start off with exception on stack
1597                 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1598 
1599                 // Register all exception ranges for catch all clause.
1600                 // The range of the catch all clause is from the beginning
1601                 // of the try or synchronized block until the present
1602                 // code pointer excluding all gaps in the current
1603                 // environment's GenContext.
1604                 int startseg = startpc;
1605                 while (env.info.gaps.nonEmpty()) {
1606                     int endseg = env.info.gaps.next().intValue();
1607                     registerCatch(body.pos(), startseg, endseg,
1608                                   catchallpc, 0);
1609                     startseg = env.info.gaps.next().intValue();
1610                 }
1611                 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1612                 code.markStatBegin();
1613 
1614                 Item excVar = makeTemp(syms.throwableType);
1615                 excVar.store();
1616                 genFinalizer(env);
1617                 code.resolvePending();
1618                 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.END_POS));
1619                 code.markStatBegin();
1620 
1621                 excVar.load();
1622                 registerCatch(body.pos(), startseg,
1623                               env.info.gaps.next().intValue(),
1624                               catchallpc, 0);
1625                 code.emitop0(athrow);
1626                 code.markDead();
1627 
1628                 // If there are jsr's to this finalizer, ...
1629                 if (env.info.cont != null) {
1630                     // Resolve all jsr's.
1631                     code.resolve(env.info.cont);
1632 
1633                     // Mark statement line number
1634                     code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1635                     code.markStatBegin();
1636 
1637                     // Save return address.
1638                     LocalItem retVar = makeTemp(syms.throwableType);
1639                     retVar.store();
1640 
1641                     // Generate finalizer code.
1642                     env.info.finalize.genLast();
1643 
1644                     // Return.

1747         /** Register a catch clause in the "Exceptions" code-attribute.
1748          */
1749         void registerCatch(DiagnosticPosition pos,
1750                            int startpc, int endpc,
1751                            int handler_pc, int catch_type) {
1752             char startpc1 = (char)startpc;
1753             char endpc1 = (char)endpc;
1754             char handler_pc1 = (char)handler_pc;
1755             if (startpc1 == startpc &&
1756                 endpc1 == endpc &&
1757                 handler_pc1 == handler_pc) {
1758                 code.addCatch(startpc1, endpc1, handler_pc1,
1759                               (char)catch_type);
1760             } else {
1761                 log.error(pos, Errors.LimitCodeTooLargeForTryStmt);
1762                 nerrs++;
1763             }
1764         }
1765 
1766     public void visitIf(JCIf tree) {









1767         int limit = code.nextreg;
1768         Chain thenExit = null;
1769         Assert.check(code.isStatementStart());
1770         CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1771                              CRT_FLOW_CONTROLLER);
1772         Chain elseChain = c.jumpFalse();
1773         Assert.check(code.isStatementStart());
1774         if (!c.isFalse()) {
1775             code.resolve(c.trueJumps);
1776             genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1777             thenExit = code.branch(goto_);
1778         }
1779         if (elseChain != null) {
1780             code.resolve(elseChain);
1781             if (tree.elsepart != null) {
1782                 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1783             }
1784         }
1785         code.resolve(thenExit);
1786         code.endScopes(limit);
1787         Assert.check(code.isStatementStart());
1788     }
1789 
1790     public void visitExec(JCExpressionStatement tree) {
1791         // Optimize x++ to ++x and x-- to --x.

2075                 nerrs++;
2076             }
2077             int elemcode = Code.arraycode(elemtype);
2078             if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
2079                 code.emitAnewarray(makeRef(pos, elemtype), type);
2080             } else if (elemcode == 1) {
2081                 code.emitMultianewarray(ndims, makeRef(pos, type), type);
2082             } else {
2083                 code.emitNewarray(elemcode, type);
2084             }
2085             return items.makeStackItem(type);
2086         }
2087 
2088     public void visitParens(JCParens tree) {
2089         result = genExpr(tree.expr, tree.expr.type);
2090     }
2091 
2092     public void visitAssign(JCAssign tree) {
2093         Item l = genExpr(tree.lhs, tree.lhs.type);
2094         genExpr(tree.rhs, tree.lhs.type).load();


2095         if (tree.rhs.type.hasTag(BOT)) {
2096             /* This is just a case of widening reference conversion that per 5.1.5 simply calls
2097                for "regarding a reference as having some other type in a manner that can be proved
2098                correct at compile time."
2099             */
2100             code.state.forceStackTop(tree.lhs.type);
2101         }
2102         result = items.makeAssignItem(l);
2103     }
2104 
2105     public void visitAssignop(JCAssignOp tree) {
2106         OperatorSymbol operator = tree.operator;
2107         Item l;
2108         if (operator.opcode == string_add) {
2109             l = concat.makeConcat(tree);
2110         } else {
2111             // Generate code for first expression
2112             l = genExpr(tree.lhs, tree.lhs.type);
2113 
2114             // If we have an increment of -32768 to +32767 of a local

2353             items.makeThisItem().load();
2354             sym = binaryQualifier(sym, env.enclClass.type);
2355             result = items.makeMemberItem(sym, nonVirtualForPrivateAccess(sym));
2356         }
2357     }
2358 
2359     //where
2360     private boolean nonVirtualForPrivateAccess(Symbol sym) {
2361         boolean useVirtual = target.hasVirtualPrivateInvoke() &&
2362                              !disableVirtualizedPrivateInvoke;
2363         return !useVirtual && ((sym.flags() & PRIVATE) != 0);
2364     }
2365 
2366     public void visitSelect(JCFieldAccess tree) {
2367         Symbol sym = tree.sym;
2368 
2369         if (tree.name == names._class) {
2370             code.emitLdc((LoadableConstant)checkDimension(tree.pos(), tree.selected.type));
2371             result = items.makeStackItem(pt);
2372             return;
2373        }
2374 
2375         Symbol ssym = TreeInfo.symbol(tree.selected);
2376 
2377         // Are we selecting via super?
2378         boolean selectSuper =
2379             ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2380 
2381         // Are we accessing a member of the superclass in an access method
2382         // resulting from a qualified super?
2383         boolean accessSuper = isAccessSuper(env.enclMethod);
2384 
2385         Item base = (selectSuper)
2386             ? items.makeSuperItem()
2387             : genExpr(tree.selected, tree.selected.type);
2388 
2389         if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2390             // We are seeing a variable that is constant but its selecting
2391             // expression is not.
2392             if ((sym.flags() & STATIC) != 0) {
2393                 if (!selectSuper && (ssym == null || ssym.kind != TYP))

  80     private final StringConcat concat;
  81 
  82     /** Format of stackmap tables to be generated. */
  83     private final Code.StackMapFormat stackMap;
  84 
  85     /** A type that serves as the expected type for all method expressions.
  86      */
  87     private final Type methodType;
  88 
  89     public static Gen instance(Context context) {
  90         Gen instance = context.get(genKey);
  91         if (instance == null)
  92             instance = new Gen(context);
  93         return instance;
  94     }
  95 
  96     /** Constant pool writer, set by genClass.
  97      */
  98     final PoolWriter poolWriter;
  99 
 100     private final UnsetFieldsInfo unsetFieldsInfo;
 101 
 102     @SuppressWarnings("this-escape")
 103     protected Gen(Context context) {
 104         context.put(genKey, this);
 105 
 106         names = Names.instance(context);
 107         log = Log.instance(context);
 108         syms = Symtab.instance(context);
 109         chk = Check.instance(context);
 110         rs = Resolve.instance(context);
 111         make = TreeMaker.instance(context);
 112         target = Target.instance(context);
 113         types = Types.instance(context);
 114         concat = StringConcat.instance(context);
 115 
 116         methodType = new MethodType(null, null, null, syms.methodClass);
 117         accessDollar = "access" + target.syntheticNameChar();
 118         lower = Lower.instance(context);
 119 
 120         Options options = Options.instance(context);
 121         lineDebugInfo =
 122             options.isUnset(G_CUSTOM) ||
 123             options.isSet(G_CUSTOM, "lines");
 124         varDebugInfo =
 125             options.isUnset(G_CUSTOM)
 126             ? options.isSet(G)
 127             : options.isSet(G_CUSTOM, "vars");
 128         genCrt = options.isSet(XJCOV);
 129         debugCode = options.isSet("debug.code");
 130         disableVirtualizedPrivateInvoke = options.isSet("disableVirtualizedPrivateInvoke");
 131         poolWriter = new PoolWriter(types, names);
 132         unsetFieldsInfo = UnsetFieldsInfo.instance(context);
 133 
 134         // ignore cldc because we cannot have both stackmap formats
 135         this.stackMap = StackMapFormat.JSR202;
 136         annotate = Annotate.instance(context);
 137         qualifiedSymbolCache = new HashMap<>();
 138         Preview preview = Preview.instance(context);
 139         Source source = Source.instance(context);
 140         allowValueClasses = (!preview.isPreview(Source.Feature.VALUE_CLASSES) || preview.isEnabled()) &&
 141                 Source.Feature.VALUE_CLASSES.allowedInSource(source);
 142     }
 143 
 144     /** Switches
 145      */
 146     private final boolean lineDebugInfo;
 147     private final boolean varDebugInfo;
 148     private final boolean genCrt;
 149     private final boolean debugCode;
 150     private boolean disableVirtualizedPrivateInvoke;
 151     private final boolean allowValueClasses;
 152 
 153     /** Code buffer, set by genMethod.
 154      */
 155     private Code code;
 156 
 157     /** Items structure, set by genMethod.
 158      */
 159     private Items items;
 160 
 161     /** Environment for symbol lookup, set by genClass
 162      */
 163     private Env<AttrContext> attrEnv;
 164 
 165     /** The top level tree.
 166      */
 167     private JCCompilationUnit toplevel;
 168 
 169     /** The number of code-gen errors in this class.
 170      */
 171     private int nerrs = 0;

 415     boolean hasFinally(JCTree target, Env<GenContext> env) {
 416         while (env.tree != target) {
 417             if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
 418                 return true;
 419             env = env.next;
 420         }
 421         return false;
 422     }
 423 
 424 /* ************************************************************************
 425  * Normalizing class-members.
 426  *************************************************************************/
 427 
 428     /** Distribute member initializer code into constructors and {@code <clinit>}
 429      *  method.
 430      *  @param defs         The list of class member declarations.
 431      *  @param c            The enclosing class.
 432      */
 433     List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
 434         ListBuffer<JCStatement> initCode = new ListBuffer<>();
 435         // only used for value classes
 436         ListBuffer<JCStatement> initBlocks = new ListBuffer<>();
 437         ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<>();
 438         ListBuffer<JCStatement> clinitCode = new ListBuffer<>();
 439         ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<>();
 440         ListBuffer<JCTree> methodDefs = new ListBuffer<>();
 441         // Sort definitions into three listbuffers:
 442         //  - initCode for instance initializers
 443         //  - clinitCode for class initializers
 444         //  - methodDefs for method definitions
 445         for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
 446             JCTree def = l.head;
 447             switch (def.getTag()) {
 448             case BLOCK:
 449                 JCBlock block = (JCBlock)def;
 450                 if ((block.flags & STATIC) != 0)
 451                     clinitCode.append(block);
 452                 else if ((block.flags & SYNTHETIC) == 0) {
 453                     if (c.isValueClass() || c.hasStrict()) {
 454                         initBlocks.append(block);
 455                     } else {
 456                         initCode.append(block);
 457                     }
 458                 }
 459                 break;
 460             case METHODDEF:
 461                 methodDefs.append(def);
 462                 break;
 463             case VARDEF:
 464                 JCVariableDecl vdef = (JCVariableDecl) def;
 465                 VarSymbol sym = vdef.sym;
 466                 checkDimension(vdef.pos(), sym.type);
 467                 if (vdef.init != null) {
 468                     if ((sym.flags() & STATIC) == 0) {
 469                         // Always initialize instance variables.
 470                         JCStatement init = make.at(vdef.pos()).
 471                             Assignment(sym, vdef.init);
 472                         initCode.append(init);
 473                         endPosTable.replaceTree(vdef, init);
 474                         initTAs.addAll(getAndRemoveNonFieldTAs(sym));
 475                     } else if (sym.getConstValue() == null) {
 476                         // Initialize class (static) variables only if
 477                         // they are not compile-time constants.
 478                         JCStatement init = make.at(vdef.pos).
 479                             Assignment(sym, vdef.init);
 480                         clinitCode.append(init);
 481                         endPosTable.replaceTree(vdef, init);
 482                         clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
 483                     } else {
 484                         checkStringConstant(vdef.init.pos(), sym.getConstValue());
 485                         /* if the init contains a reference to an external class, add it to the
 486                          * constant's pool
 487                          */
 488                         vdef.init.accept(classReferenceVisitor);
 489                     }
 490                 }
 491                 break;
 492             default:
 493                 Assert.error();
 494             }
 495         }
 496         // Insert any instance initializers into all constructors.
 497         if (initCode.length() != 0 || initBlocks.length() != 0) {

 498             initTAs.addAll(c.getInitTypeAttributes());
 499             List<Attribute.TypeCompound> initTAlist = initTAs.toList();
 500             for (JCTree t : methodDefs) {
 501                 normalizeMethod((JCMethodDecl)t, initCode.toList(), initBlocks.toList(), initTAlist);
 502             }
 503         }
 504         // If there are class initializers, create a <clinit> method
 505         // that contains them as its body.
 506         if (clinitCode.length() != 0) {
 507             MethodSymbol clinit = new MethodSymbol(
 508                 STATIC | (c.flags() & STRICTFP),
 509                 names.clinit,
 510                 new MethodType(
 511                     List.nil(), syms.voidType,
 512                     List.nil(), syms.methodClass),
 513                 c);
 514             c.members().enter(clinit);
 515             List<JCStatement> clinitStats = clinitCode.toList();
 516             JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
 517             block.bracePos = TreeInfo.endPos(clinitStats.last());
 518             methodDefs.append(make.MethodDef(clinit, block));
 519 
 520             if (!clinitTAs.isEmpty())
 521                 clinit.appendUniqueTypeAttributes(clinitTAs.toList());

 544 
 545     /** Check a constant value and report if it is a string that is
 546      *  too large.
 547      */
 548     private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
 549         if (nerrs != 0 || // only complain about a long string once
 550             constValue == null ||
 551             !(constValue instanceof String str) ||
 552             str.length() < PoolWriter.MAX_STRING_LENGTH)
 553             return;
 554         log.error(pos, Errors.LimitString);
 555         nerrs++;
 556     }
 557 
 558     /** Insert instance initializer code into constructors prior to the super() call.
 559      *  @param md        The tree potentially representing a
 560      *                   constructor's definition.
 561      *  @param initCode  The list of instance initializer statements.
 562      *  @param initTAs  Type annotations from the initializer expression.
 563      */
 564     void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<JCStatement> initBlocks,  List<TypeCompound> initTAs) {
 565         if (TreeInfo.isConstructor(md) && TreeInfo.hasConstructorCall(md, names._super)) {
 566             // We are seeing a constructor that has a super() call.
 567             // Find the super() invocation and append the given initializer code.
 568             if (allowValueClasses & (md.sym.owner.isValueClass() || md.sym.owner.hasStrict() || ((md.sym.owner.flags_field & RECORD) != 0))) {
 569                 rewriteInitializersIfNeeded(md, initCode);
 570                 md.body.stats = initCode.appendList(md.body.stats);
 571                 TreeInfo.mapSuperCalls(md.body, supercall -> make.Block(0, initBlocks.prepend(supercall)));
 572             } else {
 573                 TreeInfo.mapSuperCalls(md.body, supercall -> make.Block(0, initCode.prepend(supercall)));
 574             }
 575 
 576             if (md.body.bracePos == Position.NOPOS)
 577                 md.body.bracePos = TreeInfo.endPos(md.body.stats.last());
 578 
 579             md.sym.appendUniqueTypeAttributes(initTAs);
 580         }
 581     }
 582 
 583     void rewriteInitializersIfNeeded(JCMethodDecl md, List<JCStatement> initCode) {
 584         if (lower.initializerOuterThis.containsKey(md.sym.owner)) {
 585             InitializerVisitor initializerVisitor = new InitializerVisitor(md, lower.initializerOuterThis.get(md.sym.owner));
 586             for (JCStatement init : initCode) {
 587                 initializerVisitor.scan(init);
 588             }
 589         }
 590     }
 591 
 592     public static class InitializerVisitor extends TreeScanner {
 593         JCMethodDecl md;
 594         Set<JCExpression> exprSet;
 595 
 596         public InitializerVisitor(JCMethodDecl md, Set<JCExpression> exprSet) {
 597             this.md = md;
 598             this.exprSet = exprSet;
 599         }
 600 
 601         @Override
 602         public void visitTree(JCTree tree) {}
 603 
 604         @Override
 605         public void visitIdent(JCIdent tree) {
 606             if (exprSet.contains(tree)) {
 607                 for (JCVariableDecl param: md.params) {
 608                     if (param.name == tree.name &&
 609                             ((param.sym.flags_field & (MANDATED | NOOUTERTHIS)) == (MANDATED | NOOUTERTHIS))) {
 610                         tree.sym = param.sym;
 611                     }
 612                 }
 613             }
 614         }
 615     }
 616 
 617 /* ************************************************************************
 618  * Traversal methods
 619  *************************************************************************/
 620 
 621     /** Visitor argument: The current environment.
 622      */
 623     Env<GenContext> env;
 624 
 625     /** Visitor argument: The expected type (prototype).
 626      */
 627     Type pt;
 628 
 629     /** Visitor result: The item representing the computed value.
 630      */
 631     Item result;
 632 
 633     /** Visitor method: generate code for a definition, catching and reporting
 634      *  any completion failures.
 635      *  @param tree    The definition to be visited.
 636      *  @param env     The environment current at the definition.

 993             // Count up extra parameters
 994             if (meth.isConstructor()) {
 995                 extras++;
 996                 if (meth.enclClass().isInner() &&
 997                     !meth.enclClass().isStatic()) {
 998                     extras++;
 999                 }
1000             } else if ((tree.mods.flags & STATIC) == 0) {
1001                 extras++;
1002             }
1003             //      System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
1004             if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
1005                 ClassFile.MAX_PARAMETERS) {
1006                 log.error(tree.pos(), Errors.LimitParameters);
1007                 nerrs++;
1008             }
1009 
1010             else if (tree.body != null) {
1011                 // Create a new code structure and initialize it.
1012                 int startpcCrt = initCode(tree, env, fatcode);
1013                 Set<VarSymbol> prevUnsetFields = code.currentUnsetFields;
1014                 if (meth.isConstructor()) {
1015                     code.currentUnsetFields = unsetFieldsInfo.getUnsetFields(env.enclClass.sym, tree.body);
1016                     code.initialUnsetFields = unsetFieldsInfo.getUnsetFields(env.enclClass.sym, tree.body);
1017                 }
1018 
1019                 try {
1020                     genStat(tree.body, env);
1021                 } catch (CodeSizeOverflow e) {
1022                     // Failed due to code limit, try again with jsr/ret
1023                     startpcCrt = initCode(tree, env, fatcode);
1024                     genStat(tree.body, env);
1025                 } finally {
1026                     code.currentUnsetFields = prevUnsetFields;
1027                 }
1028 
1029                 if (code.state.stacksize != 0) {
1030                     log.error(tree.body.pos(), Errors.StackSimError(tree.sym));
1031                     throw new AssertionError();
1032                 }
1033 
1034                 // If last statement could complete normally, insert a
1035                 // return at the end.
1036                 if (code.isAlive()) {
1037                     code.statBegin(TreeInfo.endPos(tree.body));
1038                     if (env.enclMethod == null ||
1039                         env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
1040                         code.emitop0(return_);
1041                     } else {
1042                         // sometime dead code seems alive (4415991);
1043                         // generate a small loop instead
1044                         int startpc = code.entryPoint();
1045                         CondItem c = items.makeCondItem(goto_);
1046                         code.resolve(c.jumpTrue(), startpc);

1075 
1076                 // Fill in type annotation positions for exception parameters
1077                 code.fillExceptionParameterPositions();
1078             }
1079         }
1080 
1081         private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
1082             MethodSymbol meth = tree.sym;
1083 
1084             // Create a new code structure.
1085             meth.code = code = new Code(meth,
1086                                         fatcode,
1087                                         lineDebugInfo ? toplevel.lineMap : null,
1088                                         varDebugInfo,
1089                                         stackMap,
1090                                         debugCode,
1091                                         genCrt ? new CRTable(tree, env.toplevel.endPositions)
1092                                                : null,
1093                                         syms,
1094                                         types,
1095                                         poolWriter,
1096                                         allowValueClasses);
1097             items = new Items(poolWriter, code, syms, types);
1098             if (code.debugCode) {
1099                 System.err.println(meth + " for body " + tree);
1100             }
1101 
1102             // If method is not static, create a new local variable address
1103             // for `this'.
1104             if ((tree.mods.flags & STATIC) == 0) {
1105                 Type selfType = meth.owner.type;
1106                 if (meth.isConstructor() && selfType != syms.objectType)
1107                     selfType = UninitializedType.uninitializedThis(selfType);
1108                 code.setDefined(
1109                         code.newLocal(
1110                             new VarSymbol(FINAL, names._this, selfType, meth.owner)));
1111             }
1112 
1113             // Mark all parameters as defined from the beginning of
1114             // the method.
1115             for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1116                 checkDimension(l.head.pos(), l.head.sym.type);

1212     public void visitForLoop(JCForLoop tree) {
1213         int limit = code.nextreg;
1214         genStats(tree.init, env);
1215         genLoop(tree, tree.body, tree.cond, tree.step, true);
1216         code.endScopes(limit);
1217     }
1218     //where
1219         /** Generate code for a loop.
1220          *  @param loop       The tree representing the loop.
1221          *  @param body       The loop's body.
1222          *  @param cond       The loop's controlling condition.
1223          *  @param step       "Step" statements to be inserted at end of
1224          *                    each iteration.
1225          *  @param testFirst  True if the loop test belongs before the body.
1226          */
1227         private void genLoop(JCStatement loop,
1228                              JCStatement body,
1229                              JCExpression cond,
1230                              List<JCExpressionStatement> step,
1231                              boolean testFirst) {
1232             Set<VarSymbol> prevCodeUnsetFields = code.currentUnsetFields;
1233             try {
1234                 genLoopHelper(loop, body, cond, step, testFirst);
1235             } finally {
1236                 code.currentUnsetFields = prevCodeUnsetFields;
1237             }
1238         }
1239 
1240         private void genLoopHelper(JCStatement loop,
1241                              JCStatement body,
1242                              JCExpression cond,
1243                              List<JCExpressionStatement> step,
1244                              boolean testFirst) {
1245             Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1246             int startpc = code.entryPoint();
1247             if (testFirst) { //while or for loop
1248                 CondItem c;
1249                 if (cond != null) {
1250                     code.statBegin(cond.pos);
1251                     Assert.check(code.isStatementStart());
1252                     c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1253                 } else {
1254                     c = items.makeCondItem(goto_);
1255                 }
1256                 Chain loopDone = c.jumpFalse();
1257                 code.resolve(c.trueJumps);
1258                 Assert.check(code.isStatementStart());
1259                 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1260                 code.resolve(loopEnv.info.cont);
1261                 genStats(step, loopEnv);
1262                 code.resolve(code.branch(goto_), startpc);
1263                 code.resolve(loopDone);
1264             } else {

1283         }
1284 
1285     public void visitForeachLoop(JCEnhancedForLoop tree) {
1286         throw new AssertionError(); // should have been removed by Lower.
1287     }
1288 
1289     public void visitLabelled(JCLabeledStatement tree) {
1290         Env<GenContext> localEnv = env.dup(tree, new GenContext());
1291         genStat(tree.body, localEnv, CRT_STATEMENT);
1292         code.resolve(localEnv.info.exit);
1293     }
1294 
1295     public void visitSwitch(JCSwitch tree) {
1296         handleSwitch(tree, tree.selector, tree.cases, tree.patternSwitch);
1297     }
1298 
1299     @Override
1300     public void visitSwitchExpression(JCSwitchExpression tree) {
1301         code.resolvePending();
1302         boolean prevInCondSwitchExpression = inCondSwitchExpression;
1303         Set<VarSymbol> prevCodeUnsetFields = code.currentUnsetFields;
1304         try {
1305             inCondSwitchExpression = false;
1306             doHandleSwitchExpression(tree);
1307         } finally {
1308             inCondSwitchExpression = prevInCondSwitchExpression;
1309             code.currentUnsetFields = prevCodeUnsetFields;
1310         }
1311         result = items.makeStackItem(pt);
1312     }
1313 
1314     private void doHandleSwitchExpression(JCSwitchExpression tree) {
1315         List<LocalItem> prevStackBeforeSwitchExpression = stackBeforeSwitchExpression;
1316         LocalItem prevSwitchResult = switchResult;
1317         int limit = code.nextreg;
1318         try {
1319             stackBeforeSwitchExpression = List.nil();
1320             switchResult = null;
1321             if (hasTry(tree)) {
1322                 //if the switch expression contains try-catch, the catch handlers need to have
1323                 //an empty stack. So stash whole stack to local variables, and restore it before
1324                 //breaks:
1325                 while (code.state.stacksize > 0) {
1326                     Type type = code.state.peek();
1327                     Name varName = names.fromString(target.syntheticNameChar() +
1328                                                     "stack" +
1329                                                     target.syntheticNameChar() +

1365                     hasTry = true;
1366                 }
1367 
1368                 @Override
1369                 public void visitClassDef(JCClassDecl tree) {
1370                 }
1371 
1372                 @Override
1373                 public void visitLambda(JCLambda tree) {
1374                 }
1375             };
1376 
1377             HasTryScanner hasTryScanner = new HasTryScanner();
1378 
1379             hasTryScanner.scan(tree);
1380             return hasTryScanner.hasTry;
1381         }
1382 
1383     private void handleSwitch(JCTree swtch, JCExpression selector, List<JCCase> cases,
1384                               boolean patternSwitch) {
1385         Set<VarSymbol> prevCodeUnsetFields = code.currentUnsetFields;
1386         try {
1387             handleSwitchHelper(swtch, selector, cases, patternSwitch);
1388         } finally {
1389             code.currentUnsetFields = prevCodeUnsetFields;
1390         }
1391     }
1392 
1393     void handleSwitchHelper(JCTree swtch, JCExpression selector, List<JCCase> cases,
1394                       boolean patternSwitch) {
1395         int limit = code.nextreg;
1396         Assert.check(!selector.type.hasTag(CLASS));
1397         int switchStart = patternSwitch ? code.entryPoint() : -1;
1398         int startpcCrt = genCrt ? code.curCP() : 0;
1399         Assert.check(code.isStatementStart());
1400         Item sel = genExpr(selector, syms.intType);
1401         if (cases.isEmpty()) {
1402             // We are seeing:  switch <sel> {}
1403             sel.load().drop();
1404             if (genCrt)
1405                 code.crt.put(TreeInfo.skipParens(selector),
1406                         CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1407         } else {
1408             // We are seeing a nonempty switch.
1409             sel.load();
1410             if (genCrt)
1411                 code.crt.put(TreeInfo.skipParens(selector),
1412                         CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1413             Env<GenContext> switchEnv = env.dup(swtch, new GenContext());
1414             switchEnv.info.isSwitch = true;
1415 
1416             // Compute number of labels and minimum and maximum label values.
1417             // For each case, store its label in an array.
1418             int lo = Integer.MAX_VALUE;  // minimum label.
1419             int hi = Integer.MIN_VALUE;  // maximum label.
1420             int nlabels = 0;               // number of labels.
1421 
1422             int[] labels = new int[cases.length()];  // the label array.
1423             int defaultIndex = -1;     // the index of the default clause.
1424 
1425             List<JCCase> l = cases;
1426             for (int i = 0; i < labels.length; i++) {
1427                 if (l.head.labels.head instanceof JCConstantCaseLabel constLabel) {
1428                     Assert.check(l.head.labels.size() == 1);
1429                     int val = ((Number) constLabel.expr.type.constValue()).intValue();
1430                     labels[i] = val;
1431                     if (val < lo) lo = val;
1432                     if (hi < val) hi = val;
1433                     nlabels++;
1434                 } else {
1435                     Assert.check(defaultIndex == -1);
1436                     defaultIndex = i;
1437                 }
1438                 l = l.tail;
1439             }
1440 
1441             // Determine whether to issue a tableswitch or a lookupswitch
1442             // instruction.
1443             long table_space_cost = 4 + ((long) hi - lo + 1); // words
1444             long table_time_cost = 3; // comparisons
1445             long lookup_space_cost = 3 + 2 * (long) nlabels;
1446             long lookup_time_cost = nlabels;
1447             int opcode =
1448                     nlabels > 0 &&
1449                             table_space_cost + 3 * table_time_cost <=
1450                                     lookup_space_cost + 3 * lookup_time_cost
1451                             ?
1452                             tableswitch : lookupswitch;
1453 
1454             int startpc = code.curCP();    // the position of the selector operation
1455             code.emitop0(opcode);
1456             code.align(4);
1457             int tableBase = code.curCP();  // the start of the jump table
1458             int[] offsets = null;          // a table of offsets for a lookupswitch
1459             code.emit4(-1);                // leave space for default offset
1460             if (opcode == tableswitch) {
1461                 code.emit4(lo);            // minimum label
1462                 code.emit4(hi);            // maximum label
1463                 for (long i = lo; i <= hi; i++) {  // leave space for jump table
1464                     code.emit4(-1);
1465                 }
1466             } else {
1467                 code.emit4(nlabels);    // number of labels
1468                 for (int i = 0; i < nlabels; i++) {
1469                     code.emit4(-1); code.emit4(-1); // leave space for lookup table
1470                 }
1471                 offsets = new int[labels.length];
1472             }
1473             Code.State stateSwitch = code.state.dup();
1474             code.markDead();
1475 
1476             // For each case do:
1477             l = cases;
1478             for (int i = 0; i < labels.length; i++) {
1479                 JCCase c = l.head;
1480                 l = l.tail;
1481 
1482                 int pc = code.entryPoint(stateSwitch);
1483                 // Insert offset directly into code or else into the
1484                 // offsets table.
1485                 if (i != defaultIndex) {
1486                     if (opcode == tableswitch) {
1487                         code.put4(
1488                                 tableBase + 4 * (labels[i] - lo + 3),
1489                                 pc - startpc);
1490                     } else {
1491                         offsets[i] = pc - startpc;
1492                     }
1493                 } else {
1494                     code.put4(tableBase, pc - startpc);
1495                 }
1496 
1497                 // Generate code for the statements in this case.
1498                 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1499             }
1500 
1501             if (switchEnv.info.cont != null) {
1502                 Assert.check(patternSwitch);
1503                 code.resolve(switchEnv.info.cont, switchStart);
1504             }
1505 
1506             // Resolve all breaks.
1507             code.resolve(switchEnv.info.exit);
1508 
1509             // If we have not set the default offset, we do so now.

1519                     if (code.get4(t) == -1)
1520                         code.put4(t, defaultOffset);
1521                 }
1522             } else {
1523                 // Sort non-default offsets and copy into lookup table.
1524                 if (defaultIndex >= 0)
1525                     for (int i = defaultIndex; i < labels.length - 1; i++) {
1526                         labels[i] = labels[i+1];
1527                         offsets[i] = offsets[i+1];
1528                     }
1529                 if (nlabels > 0)
1530                     qsort2(labels, offsets, 0, nlabels - 1);
1531                 for (int i = 0; i < nlabels; i++) {
1532                     int caseidx = tableBase + 8 * (i + 1);
1533                     code.put4(caseidx, labels[i]);
1534                     code.put4(caseidx + 4, offsets[i]);
1535                 }
1536             }
1537 
1538             if (swtch instanceof JCSwitchExpression) {
1539                 // Emit line position for the end of a switch expression
1540                 code.statBegin(TreeInfo.endPos(swtch));
1541             }
1542         }
1543         code.endScopes(limit);
1544     }
1545 //where
1546         /** Sort (int) arrays of keys and values
1547          */
1548        static void qsort2(int[] keys, int[] values, int lo, int hi) {
1549             int i = lo;
1550             int j = hi;
1551             int pivot = keys[(i+j)/2];
1552             do {
1553                 while (keys[i] < pivot) i++;
1554                 while (pivot < keys[j]) j--;
1555                 if (i <= j) {
1556                     int temp1 = keys[i];
1557                     keys[i] = keys[j];
1558                     keys[j] = temp1;
1559                     int temp2 = values[i];
1560                     values[i] = values[j];

1623             @Override
1624             void afterBody() {
1625                 if (tree.finalizer != null && (tree.finalizer.flags & BODY_ONLY_FINALIZE) != 0) {
1626                     //for body-only finally, remove the GenFinalizer after try body
1627                     //so that the finally is not generated to catch bodies:
1628                     tryEnv.info.finalize = null;
1629                 }
1630             }
1631 
1632         };
1633         tryEnv.info.gaps = new ListBuffer<>();
1634         genTry(tree.body, tree.catchers, tryEnv);
1635     }
1636     //where
1637         /** Generate code for a try or synchronized statement
1638          *  @param body      The body of the try or synchronized statement.
1639          *  @param catchers  The list of catch clauses.
1640          *  @param env       The current environment of the body.
1641          */
1642         void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1643             Set<VarSymbol> prevCodeUnsetFields = code.currentUnsetFields;
1644             try {
1645                 genTryHelper(body, catchers, env);
1646             } finally {
1647                 code.currentUnsetFields = prevCodeUnsetFields;
1648             }
1649         }
1650 
1651         void genTryHelper(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1652             int limit = code.nextreg;
1653             int startpc = code.curCP();
1654             Code.State stateTry = code.state.dup();
1655             genStat(body, env, CRT_BLOCK);
1656             int endpc = code.curCP();
1657             List<Integer> gaps = env.info.gaps.toList();
1658             code.statBegin(TreeInfo.endPos(body));
1659             genFinalizer(env);
1660             code.statBegin(TreeInfo.endPos(env.tree));
1661             Chain exitChain;
1662             boolean actualTry = env.tree.hasTag(TRY);
1663             if (startpc == endpc && actualTry) {
1664                 exitChain = code.branch(dontgoto);
1665             } else {
1666                 exitChain = code.branch(goto_);
1667             }
1668             endFinalizerGap(env);
1669             env.info.finalize.afterBody();
1670             boolean hasFinalizer =
1671                     env.info.finalize != null &&
1672                             env.info.finalize.hasFinalizer();
1673             if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1674                 // start off with exception on stack
1675                 code.entryPoint(stateTry, l.head.param.sym.type);
1676                 genCatch(l.head, env, startpc, endpc, gaps);
1677                 genFinalizer(env);
1678                 if (hasFinalizer || l.tail.nonEmpty()) {
1679                     code.statBegin(TreeInfo.endPos(env.tree));
1680                     exitChain = Code.mergeChains(exitChain,
1681                             code.branch(goto_));
1682                 }
1683                 endFinalizerGap(env);
1684             }
1685             if (hasFinalizer && (startpc != endpc || !actualTry)) {
1686                 // Create a new register segment to avoid allocating
1687                 // the same variables in finalizers and other statements.
1688                 code.newRegSegment();
1689 
1690                 // Add a catch-all clause.
1691 
1692                 // start off with exception on stack
1693                 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1694 
1695                 // Register all exception ranges for catch all clause.
1696                 // The range of the catch all clause is from the beginning
1697                 // of the try or synchronized block until the present
1698                 // code pointer excluding all gaps in the current
1699                 // environment's GenContext.
1700                 int startseg = startpc;
1701                 while (env.info.gaps.nonEmpty()) {
1702                     int endseg = env.info.gaps.next().intValue();
1703                     registerCatch(body.pos(), startseg, endseg,
1704                             catchallpc, 0);
1705                     startseg = env.info.gaps.next().intValue();
1706                 }
1707                 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1708                 code.markStatBegin();
1709 
1710                 Item excVar = makeTemp(syms.throwableType);
1711                 excVar.store();
1712                 genFinalizer(env);
1713                 code.resolvePending();
1714                 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.END_POS));
1715                 code.markStatBegin();
1716 
1717                 excVar.load();
1718                 registerCatch(body.pos(), startseg,
1719                         env.info.gaps.next().intValue(),
1720                         catchallpc, 0);
1721                 code.emitop0(athrow);
1722                 code.markDead();
1723 
1724                 // If there are jsr's to this finalizer, ...
1725                 if (env.info.cont != null) {
1726                     // Resolve all jsr's.
1727                     code.resolve(env.info.cont);
1728 
1729                     // Mark statement line number
1730                     code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1731                     code.markStatBegin();
1732 
1733                     // Save return address.
1734                     LocalItem retVar = makeTemp(syms.throwableType);
1735                     retVar.store();
1736 
1737                     // Generate finalizer code.
1738                     env.info.finalize.genLast();
1739 
1740                     // Return.

1843         /** Register a catch clause in the "Exceptions" code-attribute.
1844          */
1845         void registerCatch(DiagnosticPosition pos,
1846                            int startpc, int endpc,
1847                            int handler_pc, int catch_type) {
1848             char startpc1 = (char)startpc;
1849             char endpc1 = (char)endpc;
1850             char handler_pc1 = (char)handler_pc;
1851             if (startpc1 == startpc &&
1852                 endpc1 == endpc &&
1853                 handler_pc1 == handler_pc) {
1854                 code.addCatch(startpc1, endpc1, handler_pc1,
1855                               (char)catch_type);
1856             } else {
1857                 log.error(pos, Errors.LimitCodeTooLargeForTryStmt);
1858                 nerrs++;
1859             }
1860         }
1861 
1862     public void visitIf(JCIf tree) {
1863         Set<VarSymbol> prevCodeUnsetFields = code.currentUnsetFields;
1864         try {
1865             visitIfHelper(tree);
1866         } finally {
1867             code.currentUnsetFields = prevCodeUnsetFields;
1868         }
1869     }
1870 
1871     public void visitIfHelper(JCIf tree) {
1872         int limit = code.nextreg;
1873         Chain thenExit = null;
1874         Assert.check(code.isStatementStart());
1875         CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1876                 CRT_FLOW_CONTROLLER);
1877         Chain elseChain = c.jumpFalse();
1878         Assert.check(code.isStatementStart());
1879         if (!c.isFalse()) {
1880             code.resolve(c.trueJumps);
1881             genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1882             thenExit = code.branch(goto_);
1883         }
1884         if (elseChain != null) {
1885             code.resolve(elseChain);
1886             if (tree.elsepart != null) {
1887                 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1888             }
1889         }
1890         code.resolve(thenExit);
1891         code.endScopes(limit);
1892         Assert.check(code.isStatementStart());
1893     }
1894 
1895     public void visitExec(JCExpressionStatement tree) {
1896         // Optimize x++ to ++x and x-- to --x.

2180                 nerrs++;
2181             }
2182             int elemcode = Code.arraycode(elemtype);
2183             if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
2184                 code.emitAnewarray(makeRef(pos, elemtype), type);
2185             } else if (elemcode == 1) {
2186                 code.emitMultianewarray(ndims, makeRef(pos, type), type);
2187             } else {
2188                 code.emitNewarray(elemcode, type);
2189             }
2190             return items.makeStackItem(type);
2191         }
2192 
2193     public void visitParens(JCParens tree) {
2194         result = genExpr(tree.expr, tree.expr.type);
2195     }
2196 
2197     public void visitAssign(JCAssign tree) {
2198         Item l = genExpr(tree.lhs, tree.lhs.type);
2199         genExpr(tree.rhs, tree.lhs.type).load();
2200         Set<VarSymbol> tmpUnsetSymbols = unsetFieldsInfo.getUnsetFields(env.enclClass.sym, tree);
2201         code.currentUnsetFields = tmpUnsetSymbols != null ? tmpUnsetSymbols : code.currentUnsetFields;
2202         if (tree.rhs.type.hasTag(BOT)) {
2203             /* This is just a case of widening reference conversion that per 5.1.5 simply calls
2204                for "regarding a reference as having some other type in a manner that can be proved
2205                correct at compile time."
2206             */
2207             code.state.forceStackTop(tree.lhs.type);
2208         }
2209         result = items.makeAssignItem(l);
2210     }
2211 
2212     public void visitAssignop(JCAssignOp tree) {
2213         OperatorSymbol operator = tree.operator;
2214         Item l;
2215         if (operator.opcode == string_add) {
2216             l = concat.makeConcat(tree);
2217         } else {
2218             // Generate code for first expression
2219             l = genExpr(tree.lhs, tree.lhs.type);
2220 
2221             // If we have an increment of -32768 to +32767 of a local

2460             items.makeThisItem().load();
2461             sym = binaryQualifier(sym, env.enclClass.type);
2462             result = items.makeMemberItem(sym, nonVirtualForPrivateAccess(sym));
2463         }
2464     }
2465 
2466     //where
2467     private boolean nonVirtualForPrivateAccess(Symbol sym) {
2468         boolean useVirtual = target.hasVirtualPrivateInvoke() &&
2469                              !disableVirtualizedPrivateInvoke;
2470         return !useVirtual && ((sym.flags() & PRIVATE) != 0);
2471     }
2472 
2473     public void visitSelect(JCFieldAccess tree) {
2474         Symbol sym = tree.sym;
2475 
2476         if (tree.name == names._class) {
2477             code.emitLdc((LoadableConstant)checkDimension(tree.pos(), tree.selected.type));
2478             result = items.makeStackItem(pt);
2479             return;
2480         }
2481 
2482         Symbol ssym = TreeInfo.symbol(tree.selected);
2483 
2484         // Are we selecting via super?
2485         boolean selectSuper =
2486             ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2487 
2488         // Are we accessing a member of the superclass in an access method
2489         // resulting from a qualified super?
2490         boolean accessSuper = isAccessSuper(env.enclMethod);
2491 
2492         Item base = (selectSuper)
2493             ? items.makeSuperItem()
2494             : genExpr(tree.selected, tree.selected.type);
2495 
2496         if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2497             // We are seeing a variable that is constant but its selecting
2498             // expression is not.
2499             if ((sym.flags() & STATIC) != 0) {
2500                 if (!selectSuper && (ssym == null || ssym.kind != TYP))
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