1 /*
2 * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.tools.javac.jvm;
27
28 import java.util.HashMap;
29 import java.util.Map;
30 import java.util.Set;
31
32 import com.sun.tools.javac.jvm.PoolConstant.LoadableConstant;
33 import com.sun.tools.javac.tree.TreeInfo.PosKind;
34 import com.sun.tools.javac.util.*;
35 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
36 import com.sun.tools.javac.util.List;
37 import com.sun.tools.javac.code.*;
38 import com.sun.tools.javac.code.Attribute.TypeCompound;
39 import com.sun.tools.javac.code.Symbol.VarSymbol;
40 import com.sun.tools.javac.comp.*;
41 import com.sun.tools.javac.tree.*;
42
43 import com.sun.tools.javac.code.Symbol.*;
44 import com.sun.tools.javac.code.Type.*;
45 import com.sun.tools.javac.jvm.Code.*;
46 import com.sun.tools.javac.jvm.Items.*;
47 import com.sun.tools.javac.resources.CompilerProperties.Errors;
48 import com.sun.tools.javac.tree.EndPosTable;
49 import com.sun.tools.javac.tree.JCTree.*;
50
51 import static com.sun.tools.javac.code.Flags.*;
52 import static com.sun.tools.javac.code.Kinds.Kind.*;
53 import static com.sun.tools.javac.code.TypeTag.*;
54 import static com.sun.tools.javac.jvm.ByteCodes.*;
55 import static com.sun.tools.javac.jvm.CRTFlags.*;
56 import static com.sun.tools.javac.main.Option.*;
57 import static com.sun.tools.javac.tree.JCTree.Tag.*;
58
59 /** This pass maps flat Java (i.e. without inner classes) to bytecodes.
60 *
61 * <p><b>This is NOT part of any supported API.
62 * If you write code that depends on this, you do so at your own risk.
63 * This code and its internal interfaces are subject to change or
64 * deletion without notice.</b>
65 */
66 public class Gen extends JCTree.Visitor {
67 private static final Object[] NO_STATIC_ARGS = new Object[0];
68 protected static final Context.Key<Gen> genKey = new Context.Key<>();
69
70 private final Log log;
71 private final Symtab syms;
72 private final Check chk;
73 private final Resolve rs;
74 private final TreeMaker make;
75 private final Names names;
76 private final Target target;
77 private final Name accessDollar;
78 private final Types types;
79 private final Lower lower;
80 private final Annotate annotate;
81 private final StringConcat concat;
82 private final TransValues transValues;
83
84 /** Format of stackmap tables to be generated. */
85 private final Code.StackMapFormat stackMap;
86
87 /** A type that serves as the expected type for all method expressions.
88 */
89 private final Type methodType;
90
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 }
97
98 /** Constant pool writer, set by genClass.
99 */
100 final PoolWriter poolWriter;
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 = names.
118 fromString("access" + target.syntheticNameChar());
119 lower = Lower.instance(context);
120 transValues = TransValues.instance(context);
121
122 Options options = Options.instance(context);
123 lineDebugInfo =
124 options.isUnset(G_CUSTOM) ||
125 options.isSet(G_CUSTOM, "lines");
126 varDebugInfo =
127 options.isUnset(G_CUSTOM)
128 ? options.isSet(G)
129 : options.isSet(G_CUSTOM, "vars");
130 genCrt = options.isSet(XJCOV);
131 debugCode = options.isSet("debug.code");
132 disableVirtualizedPrivateInvoke = options.isSet("disableVirtualizedPrivateInvoke");
133 poolWriter = new PoolWriter(types, names);
134
135 // ignore cldc because we cannot have both stackmap formats
136 this.stackMap = StackMapFormat.JSR202;
137 annotate = Annotate.instance(context);
138 Source source = Source.instance(context);
139 allowPrimitiveClasses = Source.Feature.PRIMITIVE_CLASSES.allowedInSource(source) && options.isSet("enablePrimitiveClasses");
140 qualifiedSymbolCache = new HashMap<>();
141 }
142
143 /** Switches
144 */
145 private final boolean lineDebugInfo;
146 private final boolean varDebugInfo;
147 private final boolean genCrt;
148 private final boolean debugCode;
149 private boolean disableVirtualizedPrivateInvoke;
150
151 /** Code buffer, set by genMethod.
152 */
153 private Code code;
154
155 /** Items structure, set by genMethod.
156 */
157 private Items items;
158
159 /** Environment for symbol lookup, set by genClass
160 */
161 private Env<AttrContext> attrEnv;
162
163 /** The top level tree.
164 */
165 private JCCompilationUnit toplevel;
166
167 /** The number of code-gen errors in this class.
168 */
169 private int nerrs = 0;
170
171 /** An object containing mappings of syntax trees to their
172 * ending source positions.
173 */
174 EndPosTable endPosTable;
175
176 boolean inCondSwitchExpression;
177 Chain switchExpressionTrueChain;
178 Chain switchExpressionFalseChain;
179 List<LocalItem> stackBeforeSwitchExpression;
180 LocalItem switchResult;
181 Set<JCMethodInvocation> invocationsWithPatternMatchingCatch = Set.of();
182 ListBuffer<int[]> patternMatchingInvocationRanges;
183
184 boolean allowPrimitiveClasses;
185
186 /** Cache the symbol to reflect the qualifying type.
187 * key: corresponding type
188 * value: qualified symbol
189 */
190 Map<Type, Symbol> qualifiedSymbolCache;
191
192 /** Generate code to load an integer constant.
193 * @param n The integer to be loaded.
194 */
195 void loadIntConst(int n) {
196 items.makeImmediateItem(syms.intType, n).load();
197 }
198
199 /** The opcode that loads a zero constant of a given type code.
200 * @param tc The given type code (@see ByteCode).
201 */
202 public static int zero(int tc) {
203 switch(tc) {
204 case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
205 return iconst_0;
206 case LONGcode:
207 return lconst_0;
208 case FLOATcode:
209 return fconst_0;
210 case DOUBLEcode:
211 return dconst_0;
212 default:
213 throw new AssertionError("zero");
214 }
215 }
216
217 /** The opcode that loads a one constant of a given type code.
218 * @param tc The given type code (@see ByteCode).
219 */
220 public static int one(int tc) {
221 return zero(tc) + 1;
222 }
223
224 /** Generate code to load -1 of the given type code (either int or long).
225 * @param tc The given type code (@see ByteCode).
226 */
227 void emitMinusOne(int tc) {
228 if (tc == LONGcode) {
229 items.makeImmediateItem(syms.longType, Long.valueOf(-1)).load();
230 } else {
231 code.emitop0(iconst_m1);
232 }
233 }
234
235 /** Construct a symbol to reflect the qualifying type that should
236 * appear in the byte code as per JLS 13.1.
237 *
238 * For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except
239 * for those cases where we need to work around VM bugs).
240 *
241 * For {@literal target <= 1.1}: If qualified variable or method is defined in a
242 * non-accessible class, clone it with the qualifier class as owner.
243 *
244 * @param sym The accessed symbol
245 * @param site The qualifier's type.
246 */
247 Symbol binaryQualifier(Symbol sym, Type site) {
248
249 if (site.hasTag(ARRAY)) {
250 if (sym == syms.lengthVar ||
251 sym.owner != syms.arrayClass)
252 return sym;
253 // array clone can be qualified by the array type in later targets
254 Symbol qualifier;
255 if ((qualifier = qualifiedSymbolCache.get(site)) == null) {
256 qualifier = new ClassSymbol(Flags.PUBLIC, site.tsym.name, site, syms.noSymbol);
257 qualifiedSymbolCache.put(site, qualifier);
258 }
259 return sym.clone(qualifier);
260 }
261
262 if (sym.owner == site.tsym ||
263 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
264 return sym;
265 }
266
267 // leave alone methods inherited from Object
268 // JLS 13.1.
269 if (sym.owner == syms.objectType.tsym)
270 return sym;
271
272 return sym.clone(site.tsym);
273 }
274
275 /** Insert a reference to given type in the constant pool,
276 * checking for an array with too many dimensions;
277 * return the reference's index.
278 * @param type The type for which a reference is inserted.
279 */
280 int makeRef(DiagnosticPosition pos, Type type, boolean emitQtype) {
281 checkDimension(pos, type);
282 if (emitQtype) {
283 return poolWriter.putClass(new ConstantPoolQType(type, types));
284 } else {
285 return poolWriter.putClass(type);
286 }
287 }
288
289 /** Insert a reference to given type in the constant pool,
290 * checking for an array with too many dimensions;
291 * return the reference's index.
292 * @param type The type for which a reference is inserted.
293 */
294 int makeRef(DiagnosticPosition pos, Type type) {
295 return makeRef(pos, type, false);
296 }
297
298 /** Check if the given type is an array with too many dimensions.
299 */
300 private Type checkDimension(DiagnosticPosition pos, Type t) {
301 checkDimensionInternal(pos, t);
302 return t;
303 }
304
305 private void checkDimensionInternal(DiagnosticPosition pos, Type t) {
306 switch (t.getTag()) {
307 case METHOD:
308 checkDimension(pos, t.getReturnType());
309 for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
310 checkDimension(pos, args.head);
311 break;
312 case ARRAY:
313 if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
314 log.error(pos, Errors.LimitDimensions);
315 nerrs++;
316 }
317 break;
318 default:
319 break;
320 }
321 }
322
323 /** Create a temporary variable.
324 * @param type The variable's type.
325 */
326 LocalItem makeTemp(Type type) {
327 VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
328 names.empty,
329 type,
330 env.enclMethod.sym);
331 code.newLocal(v);
332 return items.makeLocalItem(v);
333 }
334
335 /** Generate code to call a non-private method or constructor.
336 * @param pos Position to be used for error reporting.
337 * @param site The type of which the method is a member.
338 * @param name The method's name.
339 * @param argtypes The method's argument types.
340 * @param isStatic A flag that indicates whether we call a
341 * static or instance method.
342 */
343 void callMethod(DiagnosticPosition pos,
344 Type site, Name name, List<Type> argtypes,
345 boolean isStatic) {
346 Symbol msym = rs.
347 resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
348 if (isStatic) items.makeStaticItem(msym).invoke();
349 else items.makeMemberItem(msym, names.isInitOrVNew(name)).invoke();
350 }
351
352 /** Is the given method definition an access method
353 * resulting from a qualified super? This is signified by an odd
354 * access code.
355 */
356 private boolean isAccessSuper(JCMethodDecl enclMethod) {
357 return
358 (enclMethod.mods.flags & SYNTHETIC) != 0 &&
359 isOddAccessName(enclMethod.name);
360 }
361
362 /** Does given name start with "access$" and end in an odd digit?
363 */
364 private boolean isOddAccessName(Name name) {
365 return
366 name.startsWith(accessDollar) &&
367 (name.getByteAt(name.getByteLength() - 1) & 1) == 1;
368 }
369
370 /* ************************************************************************
371 * Non-local exits
372 *************************************************************************/
373
374 /** Generate code to invoke the finalizer associated with given
375 * environment.
376 * Any calls to finalizers are appended to the environments `cont' chain.
377 * Mark beginning of gap in catch all range for finalizer.
378 */
379 void genFinalizer(Env<GenContext> env) {
380 if (code.isAlive() && env.info.finalize != null)
381 env.info.finalize.gen();
382 }
383
384 /** Generate code to call all finalizers of structures aborted by
385 * a non-local
386 * exit. Return target environment of the non-local exit.
387 * @param target The tree representing the structure that's aborted
388 * @param env The environment current at the non-local exit.
389 */
390 Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
391 Env<GenContext> env1 = env;
392 while (true) {
393 genFinalizer(env1);
394 if (env1.tree == target) break;
395 env1 = env1.next;
396 }
397 return env1;
398 }
399
400 /** Mark end of gap in catch-all range for finalizer.
401 * @param env the environment which might contain the finalizer
402 * (if it does, env.info.gaps != null).
403 */
404 void endFinalizerGap(Env<GenContext> env) {
405 if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
406 env.info.gaps.append(code.curCP());
407 }
408
409 /** Mark end of all gaps in catch-all ranges for finalizers of environments
410 * lying between, and including to two environments.
411 * @param from the most deeply nested environment to mark
412 * @param to the least deeply nested environment to mark
413 */
414 void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
415 Env<GenContext> last = null;
416 while (last != to) {
417 endFinalizerGap(from);
418 last = from;
419 from = from.next;
420 }
421 }
422
423 /** Do any of the structures aborted by a non-local exit have
424 * finalizers that require an empty stack?
425 * @param target The tree representing the structure that's aborted
426 * @param env The environment current at the non-local exit.
427 */
428 boolean hasFinally(JCTree target, Env<GenContext> env) {
429 while (env.tree != target) {
430 if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
431 return true;
432 env = env.next;
433 }
434 return false;
435 }
436
437 /* ************************************************************************
438 * Normalizing class-members.
439 *************************************************************************/
440
441 /** Distribute member initializer code into constructors and {@code <clinit>}
442 * method.
443 * @param defs The list of class member declarations.
444 * @param c The enclosing class.
445 */
446 List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
447 ListBuffer<JCStatement> initCode = new ListBuffer<>();
448 ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<>();
449 ListBuffer<JCStatement> clinitCode = new ListBuffer<>();
450 ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<>();
451 ListBuffer<JCTree> methodDefs = new ListBuffer<>();
452 // Sort definitions into three listbuffers:
453 // - initCode for instance initializers
454 // - clinitCode for class initializers
455 // - methodDefs for method definitions
456 for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
457 JCTree def = l.head;
458 switch (def.getTag()) {
459 case BLOCK:
460 JCBlock block = (JCBlock)def;
461 if ((block.flags & STATIC) != 0)
462 clinitCode.append(block);
463 else if ((block.flags & SYNTHETIC) == 0)
464 initCode.append(block);
465 break;
466 case METHODDEF:
467 methodDefs.append(def);
468 break;
469 case VARDEF:
470 JCVariableDecl vdef = (JCVariableDecl) def;
471 VarSymbol sym = vdef.sym;
472 checkDimension(vdef.pos(), sym.type);
473 if (vdef.init != null) {
474 if ((sym.flags() & STATIC) == 0) {
475 // Always initialize instance variables.
476 JCStatement init = make.at(vdef.pos()).
477 Assignment(sym, vdef.init);
478 initCode.append(init);
479 endPosTable.replaceTree(vdef, init);
480 initTAs.addAll(getAndRemoveNonFieldTAs(sym));
481 } else if (sym.getConstValue() == null) {
482 // Initialize class (static) variables only if
483 // they are not compile-time constants.
484 JCStatement init = make.at(vdef.pos).
485 Assignment(sym, vdef.init);
486 clinitCode.append(init);
487 endPosTable.replaceTree(vdef, init);
488 clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
489 } else {
490 checkStringConstant(vdef.init.pos(), sym.getConstValue());
491 /* if the init contains a reference to an external class, add it to the
492 * constant's pool
493 */
494 vdef.init.accept(classReferenceVisitor);
495 }
496 }
497 break;
498 default:
499 Assert.error();
500 }
501 }
502 // Insert any instance initializers into all constructors.
503 if (initCode.length() != 0) {
504 List<JCStatement> inits = initCode.toList();
505 initTAs.addAll(c.getInitTypeAttributes());
506 List<Attribute.TypeCompound> initTAlist = initTAs.toList();
507 for (JCTree t : methodDefs) {
508 normalizeMethod((JCMethodDecl)t, inits, initTAlist);
509 }
510 }
511 // If there are class initializers, create a <clinit> method
512 // that contains them as its body.
513 if (clinitCode.length() != 0) {
514 MethodSymbol clinit = new MethodSymbol(
515 STATIC | (c.flags() & STRICTFP),
516 names.clinit,
517 new MethodType(
518 List.nil(), syms.voidType,
519 List.nil(), syms.methodClass),
520 c);
521 c.members().enter(clinit);
522 List<JCStatement> clinitStats = clinitCode.toList();
523 JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
524 block.endpos = TreeInfo.endPos(clinitStats.last());
525 methodDefs.append(make.MethodDef(clinit, block));
526
527 if (!clinitTAs.isEmpty())
528 clinit.appendUniqueTypeAttributes(clinitTAs.toList());
529 if (!c.getClassInitTypeAttributes().isEmpty())
530 clinit.appendUniqueTypeAttributes(c.getClassInitTypeAttributes());
531 }
532 // Return all method definitions.
533 return methodDefs.toList();
534 }
535
536 private List<Attribute.TypeCompound> getAndRemoveNonFieldTAs(VarSymbol sym) {
537 List<TypeCompound> tas = sym.getRawTypeAttributes();
538 ListBuffer<Attribute.TypeCompound> fieldTAs = new ListBuffer<>();
539 ListBuffer<Attribute.TypeCompound> nonfieldTAs = new ListBuffer<>();
540 for (TypeCompound ta : tas) {
541 Assert.check(ta.getPosition().type != TargetType.UNKNOWN);
542 if (ta.getPosition().type == TargetType.FIELD) {
543 fieldTAs.add(ta);
544 } else {
545 nonfieldTAs.add(ta);
546 }
547 }
548 sym.setTypeAttributes(fieldTAs.toList());
549 return nonfieldTAs.toList();
550 }
551
552 /** Check a constant value and report if it is a string that is
553 * too large.
554 */
555 private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
556 if (nerrs != 0 || // only complain about a long string once
557 constValue == null ||
558 !(constValue instanceof String str) ||
559 str.length() < PoolWriter.MAX_STRING_LENGTH)
560 return;
561 log.error(pos, Errors.LimitString);
562 nerrs++;
563 }
564
565 /** Insert instance initializer code into initial constructor.
566 * @param md The tree potentially representing a
567 * constructor's definition.
568 * @param initCode The list of instance initializer statements.
569 * @param initTAs Type annotations from the initializer expression.
570 */
571 void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<TypeCompound> initTAs) {
572 if (names.isInitOrVNew(md.name) && TreeInfo.isInitialConstructor(md)) {
573 // We are seeing a constructor that does not call another
574 // constructor of the same class.
575 List<JCStatement> stats = md.body.stats;
576 ListBuffer<JCStatement> newstats = new ListBuffer<>();
577
578 if (stats.nonEmpty()) {
579 // Copy initializers of synthetic variables generated in
580 // the translation of inner classes.
581 while (TreeInfo.isSyntheticInit(stats.head)) {
582 newstats.append(stats.head);
583 stats = stats.tail;
584 }
585 // Copy superclass constructor call
586 newstats.append(stats.head);
587 stats = stats.tail;
588 // Copy remaining synthetic initializers.
589 while (stats.nonEmpty() &&
590 TreeInfo.isSyntheticInit(stats.head)) {
591 newstats.append(stats.head);
592 stats = stats.tail;
593 }
594 // Now insert the initializer code.
595 newstats.appendList(initCode);
596 // And copy all remaining statements.
597 while (stats.nonEmpty()) {
598 newstats.append(stats.head);
599 stats = stats.tail;
600 }
601 }
602 md.body.stats = newstats.toList();
603 if (md.body.endpos == Position.NOPOS)
604 md.body.endpos = TreeInfo.endPos(md.body.stats.last());
605
606 md.sym.appendUniqueTypeAttributes(initTAs);
607 }
608 }
609
610 /* ************************************************************************
611 * Traversal methods
612 *************************************************************************/
613
614 /** Visitor argument: The current environment.
615 */
616 Env<GenContext> env;
617
618 /** Visitor argument: The expected type (prototype).
619 */
620 Type pt;
621
622 /** Visitor result: The item representing the computed value.
623 */
624 Item result;
625
626 /** Visitor method: generate code for a definition, catching and reporting
627 * any completion failures.
628 * @param tree The definition to be visited.
629 * @param env The environment current at the definition.
630 */
631 public void genDef(JCTree tree, Env<GenContext> env) {
632 Env<GenContext> prevEnv = this.env;
633 try {
634 this.env = env;
635 tree.accept(this);
636 } catch (CompletionFailure ex) {
637 chk.completionError(tree.pos(), ex);
638 } finally {
639 this.env = prevEnv;
640 }
641 }
642
643 /** Derived visitor method: check whether CharacterRangeTable
644 * should be emitted, if so, put a new entry into CRTable
645 * and call method to generate bytecode.
646 * If not, just call method to generate bytecode.
647 * @see #genStat(JCTree, Env)
648 *
649 * @param tree The tree to be visited.
650 * @param env The environment to use.
651 * @param crtFlags The CharacterRangeTable flags
652 * indicating type of the entry.
653 */
654 public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
655 if (!genCrt) {
656 genStat(tree, env);
657 return;
658 }
659 int startpc = code.curCP();
660 genStat(tree, env);
661 if (tree.hasTag(Tag.BLOCK)) crtFlags |= CRT_BLOCK;
662 code.crt.put(tree, crtFlags, startpc, code.curCP());
663 }
664
665 /** Derived visitor method: generate code for a statement.
666 */
667 public void genStat(JCTree tree, Env<GenContext> env) {
668 if (code.isAlive()) {
669 code.statBegin(tree.pos);
670 genDef(tree, env);
671 } else if (env.info.isSwitch && tree.hasTag(VARDEF)) {
672 // variables whose declarations are in a switch
673 // can be used even if the decl is unreachable.
674 code.newLocal(((JCVariableDecl) tree).sym);
675 }
676 }
677
678 /** Derived visitor method: check whether CharacterRangeTable
679 * should be emitted, if so, put a new entry into CRTable
680 * and call method to generate bytecode.
681 * If not, just call method to generate bytecode.
682 * @see #genStats(List, Env)
683 *
684 * @param trees The list of trees to be visited.
685 * @param env The environment to use.
686 * @param crtFlags The CharacterRangeTable flags
687 * indicating type of the entry.
688 */
689 public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
690 if (!genCrt) {
691 genStats(trees, env);
692 return;
693 }
694 if (trees.length() == 1) { // mark one statement with the flags
695 genStat(trees.head, env, crtFlags | CRT_STATEMENT);
696 } else {
697 int startpc = code.curCP();
698 genStats(trees, env);
699 code.crt.put(trees, crtFlags, startpc, code.curCP());
700 }
701 }
702
703 /** Derived visitor method: generate code for a list of statements.
704 */
705 public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
706 for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
707 genStat(l.head, env, CRT_STATEMENT);
708 }
709
710 /** Derived visitor method: check whether CharacterRangeTable
711 * should be emitted, if so, put a new entry into CRTable
712 * and call method to generate bytecode.
713 * If not, just call method to generate bytecode.
714 * @see #genCond(JCTree,boolean)
715 *
716 * @param tree The tree to be visited.
717 * @param crtFlags The CharacterRangeTable flags
718 * indicating type of the entry.
719 */
720 public CondItem genCond(JCTree tree, int crtFlags) {
721 if (!genCrt) return genCond(tree, false);
722 int startpc = code.curCP();
723 CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
724 code.crt.put(tree, crtFlags, startpc, code.curCP());
725 return item;
726 }
727
728 /** Derived visitor method: generate code for a boolean
729 * expression in a control-flow context.
730 * @param _tree The expression to be visited.
731 * @param markBranches The flag to indicate that the condition is
732 * a flow controller so produced conditions
733 * should contain a proper tree to generate
734 * CharacterRangeTable branches for them.
735 */
736 public CondItem genCond(JCTree _tree, boolean markBranches) {
737 JCTree inner_tree = TreeInfo.skipParens(_tree);
738 if (inner_tree.hasTag(CONDEXPR)) {
739 JCConditional tree = (JCConditional)inner_tree;
740 CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
741 if (cond.isTrue()) {
742 code.resolve(cond.trueJumps);
743 CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
744 if (markBranches) result.tree = tree.truepart;
745 return result;
746 }
747 if (cond.isFalse()) {
748 code.resolve(cond.falseJumps);
749 CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
750 if (markBranches) result.tree = tree.falsepart;
751 return result;
752 }
753 Chain secondJumps = cond.jumpFalse();
754 code.resolve(cond.trueJumps);
755 CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
756 if (markBranches) first.tree = tree.truepart;
757 Chain falseJumps = first.jumpFalse();
758 code.resolve(first.trueJumps);
759 Chain trueJumps = code.branch(goto_);
760 code.resolve(secondJumps);
761 CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
762 CondItem result = items.makeCondItem(second.opcode,
763 Code.mergeChains(trueJumps, second.trueJumps),
764 Code.mergeChains(falseJumps, second.falseJumps));
765 if (markBranches) result.tree = tree.falsepart;
766 return result;
767 } else if (inner_tree.hasTag(SWITCH_EXPRESSION)) {
768 code.resolvePending();
769
770 boolean prevInCondSwitchExpression = inCondSwitchExpression;
771 Chain prevSwitchExpressionTrueChain = switchExpressionTrueChain;
772 Chain prevSwitchExpressionFalseChain = switchExpressionFalseChain;
773 try {
774 inCondSwitchExpression = true;
775 switchExpressionTrueChain = null;
776 switchExpressionFalseChain = null;
777 try {
778 doHandleSwitchExpression((JCSwitchExpression) inner_tree);
779 } catch (CompletionFailure ex) {
780 chk.completionError(_tree.pos(), ex);
781 code.state.stacksize = 1;
782 }
783 CondItem result = items.makeCondItem(goto_,
784 switchExpressionTrueChain,
785 switchExpressionFalseChain);
786 if (markBranches) result.tree = _tree;
787 return result;
788 } finally {
789 inCondSwitchExpression = prevInCondSwitchExpression;
790 switchExpressionTrueChain = prevSwitchExpressionTrueChain;
791 switchExpressionFalseChain = prevSwitchExpressionFalseChain;
792 }
793 } else if (inner_tree.hasTag(LETEXPR) && ((LetExpr) inner_tree).needsCond) {
794 code.resolvePending();
795
796 LetExpr tree = (LetExpr) inner_tree;
797 int limit = code.nextreg;
798 int prevLetExprStart = code.setLetExprStackPos(code.state.stacksize);
799 try {
800 genStats(tree.defs, env);
801 } finally {
802 code.setLetExprStackPos(prevLetExprStart);
803 }
804 CondItem result = genCond(tree.expr, markBranches);
805 code.endScopes(limit);
806 return result;
807 } else {
808 CondItem result = genExpr(_tree, syms.booleanType).mkCond();
809 if (markBranches) result.tree = _tree;
810 return result;
811 }
812 }
813
814 public Code getCode() {
815 return code;
816 }
817
818 public Items getItems() {
819 return items;
820 }
821
822 public Env<AttrContext> getAttrEnv() {
823 return attrEnv;
824 }
825
826 /** Visitor class for expressions which might be constant expressions.
827 * This class is a subset of TreeScanner. Intended to visit trees pruned by
828 * Lower as long as constant expressions looking for references to any
829 * ClassSymbol. Any such reference will be added to the constant pool so
830 * automated tools can detect class dependencies better.
831 */
832 class ClassReferenceVisitor extends JCTree.Visitor {
833
834 @Override
835 public void visitTree(JCTree tree) {}
836
837 @Override
838 public void visitBinary(JCBinary tree) {
839 tree.lhs.accept(this);
840 tree.rhs.accept(this);
841 }
842
843 @Override
844 public void visitSelect(JCFieldAccess tree) {
845 if (tree.selected.type.hasTag(CLASS)) {
846 makeRef(tree.selected.pos(), tree.selected.type);
847 }
848 }
849
850 @Override
851 public void visitIdent(JCIdent tree) {
852 if (tree.sym.owner instanceof ClassSymbol classSymbol) {
853 poolWriter.putClass(classSymbol);
854 }
855 }
856
857 @Override
858 public void visitConditional(JCConditional tree) {
859 tree.cond.accept(this);
860 tree.truepart.accept(this);
861 tree.falsepart.accept(this);
862 }
863
864 @Override
865 public void visitUnary(JCUnary tree) {
866 tree.arg.accept(this);
867 }
868
869 @Override
870 public void visitParens(JCParens tree) {
871 tree.expr.accept(this);
872 }
873
874 @Override
875 public void visitTypeCast(JCTypeCast tree) {
876 tree.expr.accept(this);
877 }
878 }
879
880 private ClassReferenceVisitor classReferenceVisitor = new ClassReferenceVisitor();
881
882 /** Visitor method: generate code for an expression, catching and reporting
883 * any completion failures.
884 * @param tree The expression to be visited.
885 * @param pt The expression's expected type (proto-type).
886 */
887 public Item genExpr(JCTree tree, Type pt) {
888 if (!code.isAlive()) {
889 return items.makeStackItem(pt);
890 }
891
892 Type prevPt = this.pt;
893 try {
894 if (tree.type.constValue() != null) {
895 // Short circuit any expressions which are constants
896 tree.accept(classReferenceVisitor);
897 checkStringConstant(tree.pos(), tree.type.constValue());
898 Symbol sym = TreeInfo.symbol(tree);
899 if (sym != null && isConstantDynamic(sym)) {
900 result = items.makeDynamicItem(sym);
901 } else {
902 result = items.makeImmediateItem(tree.type, tree.type.constValue());
903 }
904 } else {
905 this.pt = pt;
906 tree.accept(this);
907 }
908 return result.coerce(pt);
909 } catch (CompletionFailure ex) {
910 chk.completionError(tree.pos(), ex);
911 code.state.stacksize = 1;
912 return items.makeStackItem(pt);
913 } finally {
914 this.pt = prevPt;
915 }
916 }
917
918 public boolean isConstantDynamic(Symbol sym) {
919 return sym.kind == VAR &&
920 sym instanceof DynamicVarSymbol dynamicVarSymbol &&
921 dynamicVarSymbol.isDynamic();
922 }
923
924 /** Derived visitor method: generate code for a list of method arguments.
925 * @param trees The argument expressions to be visited.
926 * @param pts The expression's expected types (i.e. the formal parameter
927 * types of the invoked method).
928 */
929 public void genArgs(List<JCExpression> trees, List<Type> pts) {
930 for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail) {
931 genExpr(l.head, pts.head).load();
932 pts = pts.tail;
933 }
934 // require lists be of same length
935 Assert.check(pts.isEmpty());
936 }
937
938 /* ************************************************************************
939 * Visitor methods for statements and definitions
940 *************************************************************************/
941
942 /** Thrown when the byte code size exceeds limit.
943 */
944 public static class CodeSizeOverflow extends RuntimeException {
945 private static final long serialVersionUID = 0;
946 public CodeSizeOverflow() {}
947 }
948
949 public void visitMethodDef(JCMethodDecl tree) {
950 // Create a new local environment that points pack at method
951 // definition.
952 Env<GenContext> localEnv = env.dup(tree);
953 localEnv.enclMethod = tree;
954 // The expected type of every return statement in this method
955 // is the method's return type.
956 this.pt = tree.sym.erasure(types).getReturnType();
957
958 checkDimension(tree.pos(), tree.sym.erasure(types));
959 genMethod(tree, localEnv, false);
960 }
961 //where
962 /** Generate code for a method.
963 * @param tree The tree representing the method definition.
964 * @param env The environment current for the method body.
965 * @param fatcode A flag that indicates whether all jumps are
966 * within 32K. We first invoke this method under
967 * the assumption that fatcode == false, i.e. all
968 * jumps are within 32K. If this fails, fatcode
969 * is set to true and we try again.
970 */
971 void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
972 MethodSymbol meth = tree.sym;
973 int extras = 0;
974 // Count up extra parameters
975 if (meth.isInitOrVNew()) {
976 extras++;
977 if (meth.enclClass().isInner() &&
978 !meth.enclClass().isStatic()) {
979 extras++;
980 }
981 } else if ((tree.mods.flags & STATIC) == 0) {
982 extras++;
983 }
984 // System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
985 if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
986 ClassFile.MAX_PARAMETERS) {
987 log.error(tree.pos(), Errors.LimitParameters);
988 nerrs++;
989 }
990
991 else if (tree.body != null) {
992 // Create a new code structure and initialize it.
993 int startpcCrt = initCode(tree, env, fatcode);
994
995 try {
996 genStat(tree.body, env);
997 } catch (CodeSizeOverflow e) {
998 // Failed due to code limit, try again with jsr/ret
999 startpcCrt = initCode(tree, env, fatcode);
1000 genStat(tree.body, env);
1001 }
1002
1003 if (code.state.stacksize != 0) {
1004 log.error(tree.body.pos(), Errors.StackSimError(tree.sym));
1005 throw new AssertionError();
1006 }
1007
1008 // If last statement could complete normally, insert a
1009 // return at the end.
1010 if (code.isAlive()) {
1011 code.statBegin(TreeInfo.endPos(tree.body));
1012 if (env.enclMethod == null ||
1013 env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
1014 code.emitop0(return_);
1015 } else if (env.enclMethod.sym.isValueObjectFactory()) {
1016 items.makeLocalItem(env.enclMethod.factoryProduct).load();
1017 code.emitop0(areturn);
1018 } else {
1019 // sometime dead code seems alive (4415991);
1020 // generate a small loop instead
1021 int startpc = code.entryPoint();
1022 CondItem c = items.makeCondItem(goto_);
1023 code.resolve(c.jumpTrue(), startpc);
1024 }
1025 }
1026 if (genCrt)
1027 code.crt.put(tree.body,
1028 CRT_BLOCK,
1029 startpcCrt,
1030 code.curCP());
1031
1032 code.endScopes(0);
1033
1034 // If we exceeded limits, panic
1035 if (code.checkLimits(tree.pos(), log)) {
1036 nerrs++;
1037 return;
1038 }
1039
1040 // If we generated short code but got a long jump, do it again
1041 // with fatCode = true.
1042 if (!fatcode && code.fatcode) genMethod(tree, env, true);
1043
1044 // Clean up
1045 if(stackMap == StackMapFormat.JSR202) {
1046 code.lastFrame = null;
1047 code.frameBeforeLast = null;
1048 }
1049
1050 // Compress exception table
1051 code.compressCatchTable();
1052
1053 // Fill in type annotation positions for exception parameters
1054 code.fillExceptionParameterPositions();
1055 }
1056 }
1057
1058 private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
1059 MethodSymbol meth = tree.sym;
1060
1061 // Create a new code structure.
1062 meth.code = code = new Code(meth,
1063 fatcode,
1064 lineDebugInfo ? toplevel.lineMap : null,
1065 varDebugInfo,
1066 stackMap,
1067 debugCode,
1068 genCrt ? new CRTable(tree, env.toplevel.endPositions)
1069 : null,
1070 syms,
1071 types,
1072 poolWriter,
1073 allowPrimitiveClasses);
1074 items = new Items(poolWriter, code, syms, types);
1075 if (code.debugCode) {
1076 System.err.println(meth + " for body " + tree);
1077 }
1078
1079 // If method is not static, create a new local variable address
1080 // for `this'.
1081 if ((tree.mods.flags & STATIC) == 0) {
1082 Type selfType = meth.owner.type;
1083 if (meth.isInitOrVNew() && selfType != syms.objectType)
1084 selfType = UninitializedType.uninitializedThis(selfType);
1085 code.setDefined(
1086 code.newLocal(
1087 new VarSymbol(FINAL, names._this, selfType, meth.owner)));
1088 }
1089
1090 // Mark all parameters as defined from the beginning of
1091 // the method.
1092 for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1093 checkDimension(l.head.pos(), l.head.sym.type);
1094 code.setDefined(code.newLocal(l.head.sym));
1095 }
1096
1097 // Get ready to generate code for method body.
1098 int startpcCrt = genCrt ? code.curCP() : 0;
1099 code.entryPoint();
1100
1101 // Suppress initial stackmap
1102 code.pendingStackMap = false;
1103
1104 return startpcCrt;
1105 }
1106
1107 public void visitVarDef(JCVariableDecl tree) {
1108 VarSymbol v = tree.sym;
1109 if (tree.init != null) {
1110 checkStringConstant(tree.init.pos(), v.getConstValue());
1111 if (v.getConstValue() == null || varDebugInfo) {
1112 Assert.check(code.isStatementStart());
1113 code.newLocal(v);
1114 genExpr(tree.init, v.erasure(types)).load();
1115 items.makeLocalItem(v).store();
1116 Assert.check(code.isStatementStart());
1117 }
1118 } else {
1119 code.newLocal(v);
1120 }
1121 checkDimension(tree.pos(), v.type);
1122 Type localType = v.erasure(types);
1123 if (localType.requiresPreload(env.enclClass.sym)) {
1124 poolWriter.enterPreloadClass((ClassSymbol) localType.tsym);
1125 }
1126 }
1127
1128 public void visitSkip(JCSkip tree) {
1129 }
1130
1131 public void visitBlock(JCBlock tree) {
1132 if (tree.patternMatchingCatch != null) {
1133 Set<JCMethodInvocation> prevInvocationsWithPatternMatchingCatch = invocationsWithPatternMatchingCatch;
1134 ListBuffer<int[]> prevRanges = patternMatchingInvocationRanges;
1135 State startState = code.state.dup();
1136 try {
1137 invocationsWithPatternMatchingCatch = tree.patternMatchingCatch.calls2Handle();
1138 patternMatchingInvocationRanges = new ListBuffer<>();
1139 doVisitBlock(tree);
1140 } finally {
1141 Chain skipCatch = code.branch(goto_);
1142 JCCatch handler = tree.patternMatchingCatch.handler();
1143 code.entryPoint(startState, handler.param.sym.type);
1144 genPatternMatchingCatch(handler, env, patternMatchingInvocationRanges.toList());
1145 code.resolve(skipCatch);
1146 invocationsWithPatternMatchingCatch = prevInvocationsWithPatternMatchingCatch;
1147 patternMatchingInvocationRanges = prevRanges;
1148 }
1149 } else {
1150 doVisitBlock(tree);
1151 }
1152 }
1153
1154 private void doVisitBlock(JCBlock tree) {
1155 int limit = code.nextreg;
1156 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1157 genStats(tree.stats, localEnv);
1158 // End the scope of all block-local variables in variable info.
1159 if (!env.tree.hasTag(METHODDEF)) {
1160 code.statBegin(tree.endpos);
1161 code.endScopes(limit);
1162 code.pendingStatPos = Position.NOPOS;
1163 }
1164 }
1165
1166 public void visitDoLoop(JCDoWhileLoop tree) {
1167 genLoop(tree, tree.body, tree.cond, List.nil(), false);
1168 }
1169
1170 public void visitWhileLoop(JCWhileLoop tree) {
1171 genLoop(tree, tree.body, tree.cond, List.nil(), true);
1172 }
1173
1174 public void visitWithField(JCWithField tree) {
1175 switch(tree.field.getTag()) {
1176 case IDENT:
1177 Symbol sym = ((JCIdent) tree.field).sym;
1178 items.makeThisItem().load();
1179 genExpr(tree.value, tree.field.type).load();
1180 sym = binaryQualifier(sym, env.enclClass.type);
1181 code.emitop2(withfield, sym, PoolWriter::putMember);
1182 result = items.makeStackItem(tree.type);
1183 break;
1184 case SELECT:
1185 JCFieldAccess fieldAccess = (JCFieldAccess) tree.field;
1186 sym = TreeInfo.symbol(fieldAccess);
1187 // JDK-8207332: To maintain the order of side effects, must compute value ahead of field
1188 genExpr(tree.value, tree.field.type).load();
1189 genExpr(fieldAccess.selected, fieldAccess.selected.type).load();
1190 if (Code.width(tree.field.type) == 2) {
1191 code.emitop0(dup_x2);
1192 code.emitop0(pop);
1193 } else {
1194 code.emitop0(swap);
1195 }
1196 sym = binaryQualifier(sym, fieldAccess.selected.type);
1197 code.emitop2(withfield, sym, PoolWriter::putMember);
1198 result = items.makeStackItem(tree.type);
1199 break;
1200 default:
1201 Assert.check(false);
1202 }
1203 }
1204
1205 public void visitForLoop(JCForLoop tree) {
1206 int limit = code.nextreg;
1207 genStats(tree.init, env);
1208 genLoop(tree, tree.body, tree.cond, tree.step, true);
1209 code.endScopes(limit);
1210 }
1211 //where
1212 /** Generate code for a loop.
1213 * @param loop The tree representing the loop.
1214 * @param body The loop's body.
1215 * @param cond The loop's controlling condition.
1216 * @param step "Step" statements to be inserted at end of
1217 * each iteration.
1218 * @param testFirst True if the loop test belongs before the body.
1219 */
1220 private void genLoop(JCStatement loop,
1221 JCStatement body,
1222 JCExpression cond,
1223 List<JCExpressionStatement> step,
1224 boolean testFirst) {
1225 Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1226 int startpc = code.entryPoint();
1227 if (testFirst) { //while or for loop
1228 CondItem c;
1229 if (cond != null) {
1230 code.statBegin(cond.pos);
1231 Assert.check(code.isStatementStart());
1232 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1233 } else {
1234 c = items.makeCondItem(goto_);
1235 }
1236 Chain loopDone = c.jumpFalse();
1237 code.resolve(c.trueJumps);
1238 Assert.check(code.isStatementStart());
1239 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1240 code.resolve(loopEnv.info.cont);
1241 genStats(step, loopEnv);
1242 code.resolve(code.branch(goto_), startpc);
1243 code.resolve(loopDone);
1244 } else {
1245 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1246 code.resolve(loopEnv.info.cont);
1247 genStats(step, loopEnv);
1248 if (code.isAlive()) {
1249 CondItem c;
1250 if (cond != null) {
1251 code.statBegin(cond.pos);
1252 Assert.check(code.isStatementStart());
1253 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1254 } else {
1255 c = items.makeCondItem(goto_);
1256 }
1257 code.resolve(c.jumpTrue(), startpc);
1258 Assert.check(code.isStatementStart());
1259 code.resolve(c.falseJumps);
1260 }
1261 }
1262 Chain exit = loopEnv.info.exit;
1263 if (exit != null) {
1264 code.resolve(exit);
1265 exit.state.defined.excludeFrom(code.nextreg);
1266 }
1267 }
1268
1269 public void visitForeachLoop(JCEnhancedForLoop tree) {
1270 throw new AssertionError(); // should have been removed by Lower.
1271 }
1272
1273 public void visitLabelled(JCLabeledStatement tree) {
1274 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1275 genStat(tree.body, localEnv, CRT_STATEMENT);
1276 Chain exit = localEnv.info.exit;
1277 if (exit != null) {
1278 code.resolve(exit);
1279 exit.state.defined.excludeFrom(code.nextreg);
1280 }
1281 }
1282
1283 public void visitSwitch(JCSwitch tree) {
1284 handleSwitch(tree, tree.selector, tree.cases, tree.patternSwitch);
1285 }
1286
1287 @Override
1288 public void visitSwitchExpression(JCSwitchExpression tree) {
1289 code.resolvePending();
1290 boolean prevInCondSwitchExpression = inCondSwitchExpression;
1291 try {
1292 inCondSwitchExpression = false;
1293 doHandleSwitchExpression(tree);
1294 } finally {
1295 inCondSwitchExpression = prevInCondSwitchExpression;
1296 }
1297 result = items.makeStackItem(pt);
1298 }
1299
1300 private void doHandleSwitchExpression(JCSwitchExpression tree) {
1301 List<LocalItem> prevStackBeforeSwitchExpression = stackBeforeSwitchExpression;
1302 LocalItem prevSwitchResult = switchResult;
1303 int limit = code.nextreg;
1304 try {
1305 stackBeforeSwitchExpression = List.nil();
1306 switchResult = null;
1307 if (hasTry(tree)) {
1308 //if the switch expression contains try-catch, the catch handlers need to have
1309 //an empty stack. So stash whole stack to local variables, and restore it before
1310 //breaks:
1311 while (code.state.stacksize > 0) {
1312 Type type = code.state.peek();
1313 Name varName = names.fromString(target.syntheticNameChar() +
1314 "stack" +
1315 target.syntheticNameChar() +
1316 tree.pos +
1317 target.syntheticNameChar() +
1318 code.state.stacksize);
1319 VarSymbol var = new VarSymbol(Flags.SYNTHETIC, varName, type,
1320 this.env.enclMethod.sym);
1321 LocalItem item = items.new LocalItem(type, code.newLocal(var));
1322 stackBeforeSwitchExpression = stackBeforeSwitchExpression.prepend(item);
1323 item.store();
1324 }
1325 switchResult = makeTemp(tree.type);
1326 }
1327 int prevLetExprStart = code.setLetExprStackPos(code.state.stacksize);
1328 try {
1329 handleSwitch(tree, tree.selector, tree.cases, tree.patternSwitch);
1330 } finally {
1331 code.setLetExprStackPos(prevLetExprStart);
1332 }
1333 } finally {
1334 stackBeforeSwitchExpression = prevStackBeforeSwitchExpression;
1335 switchResult = prevSwitchResult;
1336 code.endScopes(limit);
1337 }
1338 }
1339 //where:
1340 private boolean hasTry(JCSwitchExpression tree) {
1341 boolean[] hasTry = new boolean[1];
1342 new TreeScanner() {
1343 @Override
1344 public void visitTry(JCTry tree) {
1345 hasTry[0] = true;
1346 }
1347
1348 @Override
1349 public void visitClassDef(JCClassDecl tree) {
1350 }
1351
1352 @Override
1353 public void visitLambda(JCLambda tree) {
1354 }
1355 }.scan(tree);
1356 return hasTry[0];
1357 }
1358
1359 private void handleSwitch(JCTree swtch, JCExpression selector, List<JCCase> cases,
1360 boolean patternSwitch) {
1361 int limit = code.nextreg;
1362 Assert.check(!selector.type.hasTag(CLASS));
1363 int switchStart = patternSwitch ? code.entryPoint() : -1;
1364 int startpcCrt = genCrt ? code.curCP() : 0;
1365 Assert.check(code.isStatementStart());
1366 Item sel = genExpr(selector, syms.intType);
1367 if (cases.isEmpty()) {
1368 // We are seeing: switch <sel> {}
1369 sel.load().drop();
1370 if (genCrt)
1371 code.crt.put(TreeInfo.skipParens(selector),
1372 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1373 } else {
1374 // We are seeing a nonempty switch.
1375 sel.load();
1376 if (genCrt)
1377 code.crt.put(TreeInfo.skipParens(selector),
1378 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1379 Env<GenContext> switchEnv = env.dup(swtch, new GenContext());
1380 switchEnv.info.isSwitch = true;
1381
1382 // Compute number of labels and minimum and maximum label values.
1383 // For each case, store its label in an array.
1384 int lo = Integer.MAX_VALUE; // minimum label.
1385 int hi = Integer.MIN_VALUE; // maximum label.
1386 int nlabels = 0; // number of labels.
1387
1388 int[] labels = new int[cases.length()]; // the label array.
1389 int defaultIndex = -1; // the index of the default clause.
1390
1391 List<JCCase> l = cases;
1392 for (int i = 0; i < labels.length; i++) {
1393 if (l.head.labels.head instanceof JCConstantCaseLabel constLabel) {
1394 Assert.check(l.head.labels.size() == 1);
1395 int val = ((Number) constLabel.expr.type.constValue()).intValue();
1396 labels[i] = val;
1397 if (val < lo) lo = val;
1398 if (hi < val) hi = val;
1399 nlabels++;
1400 } else {
1401 Assert.check(defaultIndex == -1);
1402 defaultIndex = i;
1403 }
1404 l = l.tail;
1405 }
1406
1407 // Determine whether to issue a tableswitch or a lookupswitch
1408 // instruction.
1409 long table_space_cost = 4 + ((long) hi - lo + 1); // words
1410 long table_time_cost = 3; // comparisons
1411 long lookup_space_cost = 3 + 2 * (long) nlabels;
1412 long lookup_time_cost = nlabels;
1413 int opcode =
1414 nlabels > 0 &&
1415 table_space_cost + 3 * table_time_cost <=
1416 lookup_space_cost + 3 * lookup_time_cost
1417 ?
1418 tableswitch : lookupswitch;
1419
1420 int startpc = code.curCP(); // the position of the selector operation
1421 code.emitop0(opcode);
1422 code.align(4);
1423 int tableBase = code.curCP(); // the start of the jump table
1424 int[] offsets = null; // a table of offsets for a lookupswitch
1425 code.emit4(-1); // leave space for default offset
1426 if (opcode == tableswitch) {
1427 code.emit4(lo); // minimum label
1428 code.emit4(hi); // maximum label
1429 for (long i = lo; i <= hi; i++) { // leave space for jump table
1430 code.emit4(-1);
1431 }
1432 } else {
1433 code.emit4(nlabels); // number of labels
1434 for (int i = 0; i < nlabels; i++) {
1435 code.emit4(-1); code.emit4(-1); // leave space for lookup table
1436 }
1437 offsets = new int[labels.length];
1438 }
1439 Code.State stateSwitch = code.state.dup();
1440 code.markDead();
1441
1442 // For each case do:
1443 l = cases;
1444 for (int i = 0; i < labels.length; i++) {
1445 JCCase c = l.head;
1446 l = l.tail;
1447
1448 int pc = code.entryPoint(stateSwitch);
1449 // Insert offset directly into code or else into the
1450 // offsets table.
1451 if (i != defaultIndex) {
1452 if (opcode == tableswitch) {
1453 code.put4(
1454 tableBase + 4 * (labels[i] - lo + 3),
1455 pc - startpc);
1456 } else {
1457 offsets[i] = pc - startpc;
1458 }
1459 } else {
1460 code.put4(tableBase, pc - startpc);
1461 }
1462
1463 // Generate code for the statements in this case.
1464 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1465 }
1466
1467 if (switchEnv.info.cont != null) {
1468 Assert.check(patternSwitch);
1469 code.resolve(switchEnv.info.cont, switchStart);
1470 }
1471
1472 // Resolve all breaks.
1473 Chain exit = switchEnv.info.exit;
1474 if (exit != null) {
1475 code.resolve(exit);
1476 exit.state.defined.excludeFrom(limit);
1477 }
1478
1479 // If we have not set the default offset, we do so now.
1480 if (code.get4(tableBase) == -1) {
1481 code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
1482 }
1483
1484 if (opcode == tableswitch) {
1485 // Let any unfilled slots point to the default case.
1486 int defaultOffset = code.get4(tableBase);
1487 for (long i = lo; i <= hi; i++) {
1488 int t = (int)(tableBase + 4 * (i - lo + 3));
1489 if (code.get4(t) == -1)
1490 code.put4(t, defaultOffset);
1491 }
1492 } else {
1493 // Sort non-default offsets and copy into lookup table.
1494 if (defaultIndex >= 0)
1495 for (int i = defaultIndex; i < labels.length - 1; i++) {
1496 labels[i] = labels[i+1];
1497 offsets[i] = offsets[i+1];
1498 }
1499 if (nlabels > 0)
1500 qsort2(labels, offsets, 0, nlabels - 1);
1501 for (int i = 0; i < nlabels; i++) {
1502 int caseidx = tableBase + 8 * (i + 1);
1503 code.put4(caseidx, labels[i]);
1504 code.put4(caseidx + 4, offsets[i]);
1505 }
1506 }
1507 }
1508 code.endScopes(limit);
1509 }
1510 //where
1511 /** Sort (int) arrays of keys and values
1512 */
1513 static void qsort2(int[] keys, int[] values, int lo, int hi) {
1514 int i = lo;
1515 int j = hi;
1516 int pivot = keys[(i+j)/2];
1517 do {
1518 while (keys[i] < pivot) i++;
1519 while (pivot < keys[j]) j--;
1520 if (i <= j) {
1521 int temp1 = keys[i];
1522 keys[i] = keys[j];
1523 keys[j] = temp1;
1524 int temp2 = values[i];
1525 values[i] = values[j];
1526 values[j] = temp2;
1527 i++;
1528 j--;
1529 }
1530 } while (i <= j);
1531 if (lo < j) qsort2(keys, values, lo, j);
1532 if (i < hi) qsort2(keys, values, i, hi);
1533 }
1534
1535 public void visitSynchronized(JCSynchronized tree) {
1536 int limit = code.nextreg;
1537 // Generate code to evaluate lock and save in temporary variable.
1538 final LocalItem lockVar = makeTemp(syms.objectType);
1539 Assert.check(code.isStatementStart());
1540 genExpr(tree.lock, tree.lock.type).load().duplicate();
1541 lockVar.store();
1542
1543 // Generate code to enter monitor.
1544 code.emitop0(monitorenter);
1545 code.state.lock(lockVar.reg);
1546
1547 // Generate code for a try statement with given body, no catch clauses
1548 // in a new environment with the "exit-monitor" operation as finalizer.
1549 final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
1550 syncEnv.info.finalize = new GenFinalizer() {
1551 void gen() {
1552 genLast();
1553 Assert.check(syncEnv.info.gaps.length() % 2 == 0);
1554 syncEnv.info.gaps.append(code.curCP());
1555 }
1556 void genLast() {
1557 if (code.isAlive()) {
1558 lockVar.load();
1559 code.emitop0(monitorexit);
1560 code.state.unlock(lockVar.reg);
1561 }
1562 }
1563 };
1564 syncEnv.info.gaps = new ListBuffer<>();
1565 genTry(tree.body, List.nil(), syncEnv);
1566 code.endScopes(limit);
1567 }
1568
1569 public void visitTry(final JCTry tree) {
1570 // Generate code for a try statement with given body and catch clauses,
1571 // in a new environment which calls the finally block if there is one.
1572 final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
1573 final Env<GenContext> oldEnv = env;
1574 tryEnv.info.finalize = new GenFinalizer() {
1575 void gen() {
1576 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1577 tryEnv.info.gaps.append(code.curCP());
1578 genLast();
1579 }
1580 void genLast() {
1581 if (tree.finalizer != null)
1582 genStat(tree.finalizer, oldEnv, CRT_BLOCK);
1583 }
1584 boolean hasFinalizer() {
1585 return tree.finalizer != null;
1586 }
1587
1588 @Override
1589 void afterBody() {
1590 if (tree.finalizer != null && (tree.finalizer.flags & BODY_ONLY_FINALIZE) != 0) {
1591 //for body-only finally, remove the GenFinalizer after try body
1592 //so that the finally is not generated to catch bodies:
1593 tryEnv.info.finalize = null;
1594 }
1595 }
1596
1597 };
1598 tryEnv.info.gaps = new ListBuffer<>();
1599 genTry(tree.body, tree.catchers, tryEnv);
1600 }
1601 //where
1602 /** Generate code for a try or synchronized statement
1603 * @param body The body of the try or synchronized statement.
1604 * @param catchers The list of catch clauses.
1605 * @param env The current environment of the body.
1606 */
1607 void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1608 int limit = code.nextreg;
1609 int startpc = code.curCP();
1610 Code.State stateTry = code.state.dup();
1611 genStat(body, env, CRT_BLOCK);
1612 int endpc = code.curCP();
1613 List<Integer> gaps = env.info.gaps.toList();
1614 code.statBegin(TreeInfo.endPos(body));
1615 genFinalizer(env);
1616 code.statBegin(TreeInfo.endPos(env.tree));
1617 Chain exitChain;
1618 boolean actualTry = env.tree.hasTag(TRY);
1619 if (startpc == endpc && actualTry) {
1620 exitChain = code.branch(dontgoto);
1621 } else {
1622 exitChain = code.branch(goto_);
1623 }
1624 endFinalizerGap(env);
1625 env.info.finalize.afterBody();
1626 boolean hasFinalizer =
1627 env.info.finalize != null &&
1628 env.info.finalize.hasFinalizer();
1629 if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1630 // start off with exception on stack
1631 code.entryPoint(stateTry, l.head.param.sym.type);
1632 genCatch(l.head, env, startpc, endpc, gaps);
1633 genFinalizer(env);
1634 if (hasFinalizer || l.tail.nonEmpty()) {
1635 code.statBegin(TreeInfo.endPos(env.tree));
1636 exitChain = Code.mergeChains(exitChain,
1637 code.branch(goto_));
1638 }
1639 endFinalizerGap(env);
1640 }
1641 if (hasFinalizer && (startpc != endpc || !actualTry)) {
1642 // Create a new register segment to avoid allocating
1643 // the same variables in finalizers and other statements.
1644 code.newRegSegment();
1645
1646 // Add a catch-all clause.
1647
1648 // start off with exception on stack
1649 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1650
1651 // Register all exception ranges for catch all clause.
1652 // The range of the catch all clause is from the beginning
1653 // of the try or synchronized block until the present
1654 // code pointer excluding all gaps in the current
1655 // environment's GenContext.
1656 int startseg = startpc;
1657 while (env.info.gaps.nonEmpty()) {
1658 int endseg = env.info.gaps.next().intValue();
1659 registerCatch(body.pos(), startseg, endseg,
1660 catchallpc, 0);
1661 startseg = env.info.gaps.next().intValue();
1662 }
1663 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1664 code.markStatBegin();
1665
1666 Item excVar = makeTemp(syms.throwableType);
1667 excVar.store();
1668 genFinalizer(env);
1669 code.resolvePending();
1670 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.END_POS));
1671 code.markStatBegin();
1672
1673 excVar.load();
1674 registerCatch(body.pos(), startseg,
1675 env.info.gaps.next().intValue(),
1676 catchallpc, 0);
1677 code.emitop0(athrow);
1678 code.markDead();
1679
1680 // If there are jsr's to this finalizer, ...
1681 if (env.info.cont != null) {
1682 // Resolve all jsr's.
1683 code.resolve(env.info.cont);
1684
1685 // Mark statement line number
1686 code.statBegin(TreeInfo.finalizerPos(env.tree, PosKind.FIRST_STAT_POS));
1687 code.markStatBegin();
1688
1689 // Save return address.
1690 LocalItem retVar = makeTemp(syms.throwableType);
1691 retVar.store();
1692
1693 // Generate finalizer code.
1694 env.info.finalize.genLast();
1695
1696 // Return.
1697 code.emitop1w(ret, retVar.reg);
1698 code.markDead();
1699 }
1700 }
1701 // Resolve all breaks.
1702 code.resolve(exitChain);
1703
1704 code.endScopes(limit);
1705 }
1706
1707 /** Generate code for a catch clause.
1708 * @param tree The catch clause.
1709 * @param env The environment current in the enclosing try.
1710 * @param startpc Start pc of try-block.
1711 * @param endpc End pc of try-block.
1712 */
1713 void genCatch(JCCatch tree,
1714 Env<GenContext> env,
1715 int startpc, int endpc,
1716 List<Integer> gaps) {
1717 if (startpc != endpc) {
1718 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypeExprs
1719 = catchTypesWithAnnotations(tree);
1720 while (gaps.nonEmpty()) {
1721 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1722 JCExpression subCatch = subCatch1.snd;
1723 int catchType = makeRef(tree.pos(), subCatch.type);
1724 int end = gaps.head.intValue();
1725 registerCatch(tree.pos(),
1726 startpc, end, code.curCP(),
1727 catchType);
1728 for (Attribute.TypeCompound tc : subCatch1.fst) {
1729 tc.position.setCatchInfo(catchType, startpc);
1730 }
1731 }
1732 gaps = gaps.tail;
1733 startpc = gaps.head.intValue();
1734 gaps = gaps.tail;
1735 }
1736 if (startpc < endpc) {
1737 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1738 JCExpression subCatch = subCatch1.snd;
1739 int catchType = makeRef(tree.pos(), subCatch.type);
1740 registerCatch(tree.pos(),
1741 startpc, endpc, code.curCP(),
1742 catchType);
1743 for (Attribute.TypeCompound tc : subCatch1.fst) {
1744 tc.position.setCatchInfo(catchType, startpc);
1745 }
1746 }
1747 }
1748 genCatchBlock(tree, env);
1749 }
1750 }
1751 void genPatternMatchingCatch(JCCatch tree,
1752 Env<GenContext> env,
1753 List<int[]> ranges) {
1754 for (int[] range : ranges) {
1755 JCExpression subCatch = tree.param.vartype;
1756 int catchType = makeRef(tree.pos(), subCatch.type);
1757 registerCatch(tree.pos(),
1758 range[0], range[1], code.curCP(),
1759 catchType);
1760 }
1761 genCatchBlock(tree, env);
1762 }
1763 void genCatchBlock(JCCatch tree, Env<GenContext> env) {
1764 VarSymbol exparam = tree.param.sym;
1765 code.statBegin(tree.pos);
1766 code.markStatBegin();
1767 int limit = code.nextreg;
1768 code.newLocal(exparam);
1769 items.makeLocalItem(exparam).store();
1770 code.statBegin(TreeInfo.firstStatPos(tree.body));
1771 genStat(tree.body, env, CRT_BLOCK);
1772 code.endScopes(limit);
1773 code.statBegin(TreeInfo.endPos(tree.body));
1774 }
1775 // where
1776 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotations(JCCatch tree) {
1777 return TreeInfo.isMultiCatch(tree) ?
1778 catchTypesWithAnnotationsFromMulticatch((JCTypeUnion)tree.param.vartype, tree.param.sym.getRawTypeAttributes()) :
1779 List.of(new Pair<>(tree.param.sym.getRawTypeAttributes(), tree.param.vartype));
1780 }
1781 // where
1782 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotationsFromMulticatch(JCTypeUnion tree, List<TypeCompound> first) {
1783 List<JCExpression> alts = tree.alternatives;
1784 List<Pair<List<TypeCompound>, JCExpression>> res = List.of(new Pair<>(first, alts.head));
1785 alts = alts.tail;
1786
1787 while(alts != null && alts.head != null) {
1788 JCExpression alt = alts.head;
1789 if (alt instanceof JCAnnotatedType annotatedType) {
1790 res = res.prepend(new Pair<>(annotate.fromAnnotations(annotatedType.annotations), alt));
1791 } else {
1792 res = res.prepend(new Pair<>(List.nil(), alt));
1793 }
1794 alts = alts.tail;
1795 }
1796 return res.reverse();
1797 }
1798
1799 /** Register a catch clause in the "Exceptions" code-attribute.
1800 */
1801 void registerCatch(DiagnosticPosition pos,
1802 int startpc, int endpc,
1803 int handler_pc, int catch_type) {
1804 char startpc1 = (char)startpc;
1805 char endpc1 = (char)endpc;
1806 char handler_pc1 = (char)handler_pc;
1807 if (startpc1 == startpc &&
1808 endpc1 == endpc &&
1809 handler_pc1 == handler_pc) {
1810 code.addCatch(startpc1, endpc1, handler_pc1,
1811 (char)catch_type);
1812 } else {
1813 log.error(pos, Errors.LimitCodeTooLargeForTryStmt);
1814 nerrs++;
1815 }
1816 }
1817
1818 public void visitIf(JCIf tree) {
1819 int limit = code.nextreg;
1820 Chain thenExit = null;
1821 Assert.check(code.isStatementStart());
1822 CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1823 CRT_FLOW_CONTROLLER);
1824 Chain elseChain = c.jumpFalse();
1825 Assert.check(code.isStatementStart());
1826 if (!c.isFalse()) {
1827 code.resolve(c.trueJumps);
1828 genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1829 thenExit = code.branch(goto_);
1830 }
1831 if (elseChain != null) {
1832 code.resolve(elseChain);
1833 if (tree.elsepart != null) {
1834 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1835 }
1836 }
1837 code.resolve(thenExit);
1838 code.endScopes(limit);
1839 Assert.check(code.isStatementStart());
1840 }
1841
1842 public void visitExec(JCExpressionStatement tree) {
1843 // Optimize x++ to ++x and x-- to --x.
1844 JCExpression e = tree.expr;
1845 switch (e.getTag()) {
1846 case POSTINC:
1847 ((JCUnary) e).setTag(PREINC);
1848 break;
1849 case POSTDEC:
1850 ((JCUnary) e).setTag(PREDEC);
1851 break;
1852 }
1853 Assert.check(code.isStatementStart());
1854 genExpr(tree.expr, tree.expr.type).drop();
1855 Assert.check(code.isStatementStart());
1856 }
1857
1858 public void visitBreak(JCBreak tree) {
1859 Assert.check(code.isStatementStart());
1860 final Env<GenContext> targetEnv = unwindBreak(tree.target);
1861 targetEnv.info.addExit(code.branch(goto_));
1862 endFinalizerGaps(env, targetEnv);
1863 }
1864
1865 public void visitYield(JCYield tree) {
1866 Assert.check(code.isStatementStart());
1867 final Env<GenContext> targetEnv;
1868 if (inCondSwitchExpression) {
1869 CondItem value = genCond(tree.value, CRT_FLOW_TARGET);
1870 Chain falseJumps = value.jumpFalse();
1871
1872 code.resolve(value.trueJumps);
1873 Env<GenContext> localEnv = unwindBreak(tree.target);
1874 reloadStackBeforeSwitchExpr();
1875 Chain trueJumps = code.branch(goto_);
1876
1877 endFinalizerGaps(env, localEnv);
1878
1879 code.resolve(falseJumps);
1880 targetEnv = unwindBreak(tree.target);
1881 reloadStackBeforeSwitchExpr();
1882 falseJumps = code.branch(goto_);
1883
1884 if (switchExpressionTrueChain == null) {
1885 switchExpressionTrueChain = trueJumps;
1886 } else {
1887 switchExpressionTrueChain =
1888 Code.mergeChains(switchExpressionTrueChain, trueJumps);
1889 }
1890 if (switchExpressionFalseChain == null) {
1891 switchExpressionFalseChain = falseJumps;
1892 } else {
1893 switchExpressionFalseChain =
1894 Code.mergeChains(switchExpressionFalseChain, falseJumps);
1895 }
1896 } else {
1897 genExpr(tree.value, pt).load();
1898 if (switchResult != null)
1899 switchResult.store();
1900
1901 targetEnv = unwindBreak(tree.target);
1902
1903 if (code.isAlive()) {
1904 reloadStackBeforeSwitchExpr();
1905 if (switchResult != null)
1906 switchResult.load();
1907
1908 code.state.forceStackTop(tree.target.type);
1909 targetEnv.info.addExit(code.branch(goto_));
1910 code.markDead();
1911 }
1912 }
1913 endFinalizerGaps(env, targetEnv);
1914 }
1915 //where:
1916 /** As side-effect, might mark code as dead disabling any further emission.
1917 */
1918 private Env<GenContext> unwindBreak(JCTree target) {
1919 int tmpPos = code.pendingStatPos;
1920 Env<GenContext> targetEnv = unwind(target, env);
1921 code.pendingStatPos = tmpPos;
1922 return targetEnv;
1923 }
1924
1925 private void reloadStackBeforeSwitchExpr() {
1926 for (LocalItem li : stackBeforeSwitchExpression)
1927 li.load();
1928 }
1929
1930 public void visitContinue(JCContinue tree) {
1931 int tmpPos = code.pendingStatPos;
1932 Env<GenContext> targetEnv = unwind(tree.target, env);
1933 code.pendingStatPos = tmpPos;
1934 Assert.check(code.isStatementStart());
1935 targetEnv.info.addCont(code.branch(goto_));
1936 endFinalizerGaps(env, targetEnv);
1937 }
1938
1939 public void visitReturn(JCReturn tree) {
1940 int limit = code.nextreg;
1941 final Env<GenContext> targetEnv;
1942
1943 /* Save and then restore the location of the return in case a finally
1944 * is expanded (with unwind()) in the middle of our bytecodes.
1945 */
1946 int tmpPos = code.pendingStatPos;
1947 if (tree.expr != null) {
1948 Assert.check(code.isStatementStart());
1949 Item r = genExpr(tree.expr, pt).load();
1950 if (hasFinally(env.enclMethod, env)) {
1951 r = makeTemp(pt);
1952 r.store();
1953 }
1954 targetEnv = unwind(env.enclMethod, env);
1955 code.pendingStatPos = tmpPos;
1956 r.load();
1957 code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
1958 } else {
1959 targetEnv = unwind(env.enclMethod, env);
1960 code.pendingStatPos = tmpPos;
1961 code.emitop0(return_);
1962 }
1963 endFinalizerGaps(env, targetEnv);
1964 code.endScopes(limit);
1965 }
1966
1967 public void visitThrow(JCThrow tree) {
1968 Assert.check(code.isStatementStart());
1969 genExpr(tree.expr, tree.expr.type).load();
1970 code.emitop0(athrow);
1971 Assert.check(code.isStatementStart());
1972 }
1973
1974 /* ************************************************************************
1975 * Visitor methods for expressions
1976 *************************************************************************/
1977
1978 public void visitApply(JCMethodInvocation tree) {
1979 setTypeAnnotationPositions(tree.pos);
1980 // Generate code for method.
1981 Item m = genExpr(tree.meth, methodType);
1982 // Generate code for all arguments, where the expected types are
1983 // the parameters of the method's external type (that is, any implicit
1984 // outer instance of a super(...) call appears as first parameter).
1985 MethodSymbol msym = (MethodSymbol)TreeInfo.symbol(tree.meth);
1986 genArgs(tree.args,
1987 msym.externalType(types).getParameterTypes());
1988 if (!msym.isDynamic()) {
1989 code.statBegin(tree.pos);
1990 }
1991 if (invocationsWithPatternMatchingCatch.contains(tree)) {
1992 int start = code.curCP();
1993 result = m.invoke();
1994 patternMatchingInvocationRanges.add(new int[] {start, code.curCP()});
1995 } else {
1996 result = m.invoke();
1997 }
1998 }
1999
2000 public void visitConditional(JCConditional tree) {
2001 Chain thenExit = null;
2002 code.statBegin(tree.cond.pos);
2003 CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
2004 Chain elseChain = c.jumpFalse();
2005 if (!c.isFalse()) {
2006 code.resolve(c.trueJumps);
2007 int startpc = genCrt ? code.curCP() : 0;
2008 code.statBegin(tree.truepart.pos);
2009 genExpr(tree.truepart, pt).load();
2010 code.state.forceStackTop(tree.type);
2011 if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
2012 startpc, code.curCP());
2013 thenExit = code.branch(goto_);
2014 }
2015 if (elseChain != null) {
2016 code.resolve(elseChain);
2017 int startpc = genCrt ? code.curCP() : 0;
2018 code.statBegin(tree.falsepart.pos);
2019 genExpr(tree.falsepart, pt).load();
2020 code.state.forceStackTop(tree.type);
2021 if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
2022 startpc, code.curCP());
2023 }
2024 code.resolve(thenExit);
2025 result = items.makeStackItem(pt);
2026 }
2027
2028 private void setTypeAnnotationPositions(int treePos) {
2029 MethodSymbol meth = code.meth;
2030 boolean initOrClinit = code.meth.getKind() == javax.lang.model.element.ElementKind.CONSTRUCTOR
2031 || code.meth.getKind() == javax.lang.model.element.ElementKind.STATIC_INIT;
2032
2033 for (Attribute.TypeCompound ta : meth.getRawTypeAttributes()) {
2034 if (ta.hasUnknownPosition())
2035 ta.tryFixPosition();
2036
2037 if (ta.position.matchesPos(treePos))
2038 ta.position.updatePosOffset(code.cp);
2039 }
2040
2041 if (!initOrClinit)
2042 return;
2043
2044 for (Attribute.TypeCompound ta : meth.owner.getRawTypeAttributes()) {
2045 if (ta.hasUnknownPosition())
2046 ta.tryFixPosition();
2047
2048 if (ta.position.matchesPos(treePos))
2049 ta.position.updatePosOffset(code.cp);
2050 }
2051
2052 ClassSymbol clazz = meth.enclClass();
2053 for (Symbol s : new com.sun.tools.javac.model.FilteredMemberList(clazz.members())) {
2054 if (!s.getKind().isField())
2055 continue;
2056
2057 for (Attribute.TypeCompound ta : s.getRawTypeAttributes()) {
2058 if (ta.hasUnknownPosition())
2059 ta.tryFixPosition();
2060
2061 if (ta.position.matchesPos(treePos))
2062 ta.position.updatePosOffset(code.cp);
2063 }
2064 }
2065 }
2066
2067 public void visitNewClass(JCNewClass tree) {
2068 // Enclosing instances or anonymous classes should have been eliminated
2069 // by now.
2070 Assert.check(tree.encl == null && tree.def == null);
2071 setTypeAnnotationPositions(tree.pos);
2072
2073 code.emitop2(new_, checkDimension(tree.pos(), tree.type), PoolWriter::putClass);
2074 code.emitop0(dup);
2075
2076 // Generate code for all arguments, where the expected types are
2077 // the parameters of the constructor's external type (that is,
2078 // any implicit outer instance appears as first parameter).
2079 genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
2080
2081 items.makeMemberItem(tree.constructor, true).invoke();
2082 result = items.makeStackItem(tree.type);
2083 }
2084
2085 public void visitNewArray(JCNewArray tree) {
2086 setTypeAnnotationPositions(tree.pos);
2087
2088 if (tree.elems != null) {
2089 Type elemtype = types.elemtype(tree.type);
2090 loadIntConst(tree.elems.length());
2091 Item arr = makeNewArray(tree.pos(), tree.type, 1);
2092 int i = 0;
2093 for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
2094 arr.duplicate();
2095 loadIntConst(i);
2096 i++;
2097 genExpr(l.head, elemtype).load();
2098 items.makeIndexedItem(elemtype).store();
2099 }
2100 result = arr;
2101 } else {
2102 for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
2103 genExpr(l.head, syms.intType).load();
2104 }
2105 result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
2106 }
2107 }
2108 //where
2109 /** Generate code to create an array with given element type and number
2110 * of dimensions.
2111 */
2112 Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
2113 Type elemtype = types.elemtype(type);
2114 if (types.dimensions(type) > ClassFile.MAX_DIMENSIONS) {
2115 log.error(pos, Errors.LimitDimensions);
2116 nerrs++;
2117 }
2118 int elemcode = Code.arraycode(elemtype);
2119 if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
2120 code.emitAnewarray(makeRef(pos, elemtype, elemtype.isPrimitiveClass()), type);
2121 } else if (elemcode == 1) {
2122 code.emitMultianewarray(ndims, makeRef(pos, type), type);
2123 } else {
2124 code.emitNewarray(elemcode, type);
2125 }
2126 return items.makeStackItem(type);
2127 }
2128
2129 public void visitParens(JCParens tree) {
2130 result = genExpr(tree.expr, tree.expr.type);
2131 }
2132
2133 public void visitAssign(JCAssign tree) {
2134 Item l = genExpr(tree.lhs, tree.lhs.type);
2135 genExpr(tree.rhs, tree.lhs.type).load();
2136 if (tree.rhs.type.hasTag(BOT)) {
2137 /* This is just a case of widening reference conversion that per 5.1.5 simply calls
2138 for "regarding a reference as having some other type in a manner that can be proved
2139 correct at compile time."
2140 */
2141 code.state.forceStackTop(tree.lhs.type);
2142 }
2143 result = items.makeAssignItem(l);
2144 }
2145
2146 public void visitAssignop(JCAssignOp tree) {
2147 OperatorSymbol operator = tree.operator;
2148 Item l;
2149 if (operator.opcode == string_add) {
2150 l = concat.makeConcat(tree);
2151 } else {
2152 // Generate code for first expression
2153 l = genExpr(tree.lhs, tree.lhs.type);
2154
2155 // If we have an increment of -32768 to +32767 of a local
2156 // int variable we can use an incr instruction instead of
2157 // proceeding further.
2158 if ((tree.hasTag(PLUS_ASG) || tree.hasTag(MINUS_ASG)) &&
2159 l instanceof LocalItem localItem &&
2160 tree.lhs.type.getTag().isSubRangeOf(INT) &&
2161 tree.rhs.type.getTag().isSubRangeOf(INT) &&
2162 tree.rhs.type.constValue() != null) {
2163 int ival = ((Number) tree.rhs.type.constValue()).intValue();
2164 if (tree.hasTag(MINUS_ASG)) ival = -ival;
2165 localItem.incr(ival);
2166 result = l;
2167 return;
2168 }
2169 // Otherwise, duplicate expression, load one copy
2170 // and complete binary operation.
2171 l.duplicate();
2172 l.coerce(operator.type.getParameterTypes().head).load();
2173 completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
2174 }
2175 result = items.makeAssignItem(l);
2176 }
2177
2178 public void visitUnary(JCUnary tree) {
2179 OperatorSymbol operator = tree.operator;
2180 if (tree.hasTag(NOT)) {
2181 CondItem od = genCond(tree.arg, false);
2182 result = od.negate();
2183 } else {
2184 Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
2185 switch (tree.getTag()) {
2186 case POS:
2187 result = od.load();
2188 break;
2189 case NEG:
2190 result = od.load();
2191 code.emitop0(operator.opcode);
2192 break;
2193 case COMPL:
2194 result = od.load();
2195 emitMinusOne(od.typecode);
2196 code.emitop0(operator.opcode);
2197 break;
2198 case PREINC: case PREDEC:
2199 od.duplicate();
2200 if (od instanceof LocalItem localItem &&
2201 (operator.opcode == iadd || operator.opcode == isub)) {
2202 localItem.incr(tree.hasTag(PREINC) ? 1 : -1);
2203 result = od;
2204 } else {
2205 od.load();
2206 code.emitop0(one(od.typecode));
2207 code.emitop0(operator.opcode);
2208 // Perform narrowing primitive conversion if byte,
2209 // char, or short. Fix for 4304655.
2210 if (od.typecode != INTcode &&
2211 Code.truncate(od.typecode) == INTcode)
2212 code.emitop0(int2byte + od.typecode - BYTEcode);
2213 result = items.makeAssignItem(od);
2214 }
2215 break;
2216 case POSTINC: case POSTDEC:
2217 od.duplicate();
2218 if (od instanceof LocalItem localItem &&
2219 (operator.opcode == iadd || operator.opcode == isub)) {
2220 Item res = od.load();
2221 localItem.incr(tree.hasTag(POSTINC) ? 1 : -1);
2222 result = res;
2223 } else {
2224 Item res = od.load();
2225 od.stash(od.typecode);
2226 code.emitop0(one(od.typecode));
2227 code.emitop0(operator.opcode);
2228 // Perform narrowing primitive conversion if byte,
2229 // char, or short. Fix for 4304655.
2230 if (od.typecode != INTcode &&
2231 Code.truncate(od.typecode) == INTcode)
2232 code.emitop0(int2byte + od.typecode - BYTEcode);
2233 od.store();
2234 result = res;
2235 }
2236 break;
2237 case NULLCHK:
2238 result = od.load();
2239 code.emitop0(dup);
2240 genNullCheck(tree);
2241 break;
2242 default:
2243 Assert.error();
2244 }
2245 }
2246 }
2247
2248 /** Generate a null check from the object value at stack top. */
2249 private void genNullCheck(JCTree tree) {
2250 code.statBegin(tree.pos);
2251 callMethod(tree.pos(), syms.objectsType, names.requireNonNull,
2252 List.of(syms.objectType), true);
2253 code.emitop0(pop);
2254 }
2255
2256 public void visitBinary(JCBinary tree) {
2257 OperatorSymbol operator = tree.operator;
2258 if (operator.opcode == string_add) {
2259 result = concat.makeConcat(tree);
2260 } else if (tree.hasTag(AND)) {
2261 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
2262 if (!lcond.isFalse()) {
2263 Chain falseJumps = lcond.jumpFalse();
2264 code.resolve(lcond.trueJumps);
2265 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
2266 result = items.
2267 makeCondItem(rcond.opcode,
2268 rcond.trueJumps,
2269 Code.mergeChains(falseJumps,
2270 rcond.falseJumps));
2271 } else {
2272 result = lcond;
2273 }
2274 } else if (tree.hasTag(OR)) {
2275 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
2276 if (!lcond.isTrue()) {
2277 Chain trueJumps = lcond.jumpTrue();
2278 code.resolve(lcond.falseJumps);
2279 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
2280 result = items.
2281 makeCondItem(rcond.opcode,
2282 Code.mergeChains(trueJumps, rcond.trueJumps),
2283 rcond.falseJumps);
2284 } else {
2285 result = lcond;
2286 }
2287 } else {
2288 Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
2289 od.load();
2290 result = completeBinop(tree.lhs, tree.rhs, operator);
2291 }
2292 }
2293
2294
2295 /** Complete generating code for operation, with left operand
2296 * already on stack.
2297 * @param lhs The tree representing the left operand.
2298 * @param rhs The tree representing the right operand.
2299 * @param operator The operator symbol.
2300 */
2301 Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
2302 MethodType optype = (MethodType)operator.type;
2303 int opcode = operator.opcode;
2304 if (opcode >= if_icmpeq && opcode <= if_icmple &&
2305 rhs.type.constValue() instanceof Number number &&
2306 number.intValue() == 0) {
2307 opcode = opcode + (ifeq - if_icmpeq);
2308 } else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
2309 TreeInfo.isNull(rhs)) {
2310 opcode = opcode + (if_acmp_null - if_acmpeq);
2311 } else {
2312 // The expected type of the right operand is
2313 // the second parameter type of the operator, except for
2314 // shifts with long shiftcount, where we convert the opcode
2315 // to a short shift and the expected type to int.
2316 Type rtype = operator.erasure(types).getParameterTypes().tail.head;
2317 if (opcode >= ishll && opcode <= lushrl) {
2318 opcode = opcode + (ishl - ishll);
2319 rtype = syms.intType;
2320 }
2321 // Generate code for right operand and load.
2322 genExpr(rhs, rtype).load();
2323 // If there are two consecutive opcode instructions,
2324 // emit the first now.
2325 if (opcode >= (1 << preShift)) {
2326 code.emitop0(opcode >> preShift);
2327 opcode = opcode & 0xFF;
2328 }
2329 }
2330 if (opcode >= ifeq && opcode <= if_acmpne ||
2331 opcode == if_acmp_null || opcode == if_acmp_nonnull) {
2332 return items.makeCondItem(opcode);
2333 } else {
2334 code.emitop0(opcode);
2335 return items.makeStackItem(optype.restype);
2336 }
2337 }
2338
2339 public void visitTypeCast(JCTypeCast tree) {
2340 result = genExpr(tree.expr, tree.clazz.type).load();
2341 setTypeAnnotationPositions(tree.pos);
2342 // Additional code is only needed if we cast to a reference type
2343 // which is not statically a supertype of the expression's type.
2344 // For basic types, the coerce(...) in genExpr(...) will do
2345 // the conversion.
2346 // primitive reference conversion is a nop when we bifurcate the primitive class, as the VM sees a subtyping relationship.
2347 if (!tree.clazz.type.isPrimitive() &&
2348 !types.isSameType(tree.expr.type, tree.clazz.type) &&
2349 (!tree.clazz.type.isReferenceProjection() || !types.isSameType(tree.clazz.type.valueProjection(), tree.expr.type) || true) &&
2350 !types.isSubtype(tree.expr.type, tree.clazz.type)) {
2351 checkDimension(tree.pos(), tree.clazz.type);
2352 if (tree.clazz.type.isPrimitiveClass()) {
2353 code.emitop2(checkcast, new ConstantPoolQType(tree.clazz.type, types), PoolWriter::putClass);
2354 } else {
2355 code.emitop2(checkcast, tree.clazz.type, PoolWriter::putClass);
2356 }
2357
2358 }
2359 }
2360
2361 public void visitWildcard(JCWildcard tree) {
2362 throw new AssertionError(this.getClass().getName());
2363 }
2364
2365 public void visitTypeTest(JCInstanceOf tree) {
2366 genExpr(tree.expr, tree.expr.type).load();
2367 setTypeAnnotationPositions(tree.pos);
2368 code.emitop2(instanceof_, makeRef(tree.pos(), tree.pattern.type));
2369 result = items.makeStackItem(syms.booleanType);
2370 }
2371
2372 public void visitIndexed(JCArrayAccess tree) {
2373 genExpr(tree.indexed, tree.indexed.type).load();
2374 genExpr(tree.index, syms.intType).load();
2375 result = items.makeIndexedItem(tree.type);
2376 }
2377
2378 public void visitIdent(JCIdent tree) {
2379 Symbol sym = tree.sym;
2380 if (tree.name == names._this || tree.name == names._super) {
2381 Item res = tree.name == names._this
2382 ? items.makeThisItem()
2383 : items.makeSuperItem();
2384 if (sym.kind == MTH) {
2385 // Generate code to address the constructor.
2386 res.load();
2387 res = items.makeMemberItem(sym, true);
2388 }
2389 result = res;
2390 } else if (isInvokeDynamic(sym) || isConstantDynamic(sym)) {
2391 if (isConstantDynamic(sym)) {
2392 setTypeAnnotationPositions(tree.pos);
2393 }
2394 result = items.makeDynamicItem(sym);
2395 } else if (sym.kind == VAR && (sym.owner.kind == MTH || sym.owner.kind == VAR)) {
2396 result = items.makeLocalItem((VarSymbol)sym);
2397 } else if ((sym.flags() & STATIC) != 0) {
2398 if (!isAccessSuper(env.enclMethod))
2399 sym = binaryQualifier(sym, env.enclClass.type);
2400 result = items.makeStaticItem(sym);
2401 } else {
2402 items.makeThisItem().load();
2403 sym = binaryQualifier(sym, env.enclClass.type);
2404 result = items.makeMemberItem(sym, nonVirtualForPrivateAccess(sym));
2405 }
2406 }
2407
2408 //where
2409 private boolean nonVirtualForPrivateAccess(Symbol sym) {
2410 boolean useVirtual = target.hasVirtualPrivateInvoke() &&
2411 !disableVirtualizedPrivateInvoke;
2412 return !useVirtual && ((sym.flags() & PRIVATE) != 0);
2413 }
2414
2415 public void visitSelect(JCFieldAccess tree) {
2416 Symbol sym = tree.sym;
2417
2418 if (tree.name == names._class) {
2419 code.emitLdc((LoadableConstant) tree.selected.type, makeRef(tree.pos(), tree.selected.type, tree.selected.type.isPrimitiveClass()));
2420 result = items.makeStackItem(pt);
2421 return;
2422 }
2423
2424 Symbol ssym = TreeInfo.symbol(tree.selected);
2425
2426 // Are we selecting via super?
2427 boolean selectSuper =
2428 ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2429
2430 // Are we accessing a member of the superclass in an access method
2431 // resulting from a qualified super?
2432 boolean accessSuper = isAccessSuper(env.enclMethod);
2433
2434 Item base = (selectSuper)
2435 ? items.makeSuperItem()
2436 : genExpr(tree.selected, tree.selected.type);
2437
2438 if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2439 // We are seeing a variable that is constant but its selecting
2440 // expression is not.
2441 if ((sym.flags() & STATIC) != 0) {
2442 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2443 base = base.load();
2444 base.drop();
2445 } else {
2446 base.load();
2447 genNullCheck(tree.selected);
2448 }
2449 result = items.
2450 makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
2451 } else {
2452 if (isInvokeDynamic(sym)) {
2453 result = items.makeDynamicItem(sym);
2454 return;
2455 } else {
2456 sym = binaryQualifier(sym, tree.selected.type);
2457 }
2458 if ((sym.flags() & STATIC) != 0) {
2459 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2460 base = base.load();
2461 base.drop();
2462 result = items.makeStaticItem(sym);
2463 } else {
2464 base.load();
2465 if (sym == syms.lengthVar) {
2466 code.emitop0(arraylength);
2467 result = items.makeStackItem(syms.intType);
2468 } else {
2469 result = items.
2470 makeMemberItem(sym,
2471 nonVirtualForPrivateAccess(sym) ||
2472 selectSuper || accessSuper);
2473 }
2474 }
2475 }
2476 }
2477
2478 public void visitDefaultValue(JCDefaultValue tree) {
2479 if (tree.type.isValueClass()) {
2480 code.emitop2(aconst_init, checkDimension(tree.pos(), tree.type), PoolWriter::putClass);
2481 } else if (tree.type.isReference()) {
2482 code.emitop0(aconst_null);
2483 } else {
2484 code.emitop0(zero(Code.typecode(tree.type)));
2485 }
2486 result = items.makeStackItem(tree.type);
2487 return;
2488 }
2489
2490 public boolean isInvokeDynamic(Symbol sym) {
2491 return sym.kind == MTH && ((MethodSymbol)sym).isDynamic();
2492 }
2493
2494 public void visitLiteral(JCLiteral tree) {
2495 if (tree.type.hasTag(BOT)) {
2496 code.emitop0(aconst_null);
2497 result = items.makeStackItem(tree.type);
2498 }
2499 else
2500 result = items.makeImmediateItem(tree.type, tree.value);
2501 }
2502
2503 public void visitLetExpr(LetExpr tree) {
2504 code.resolvePending();
2505
2506 int limit = code.nextreg;
2507 int prevLetExprStart = code.setLetExprStackPos(code.state.stacksize);
2508 try {
2509 genStats(tree.defs, env);
2510 } finally {
2511 code.setLetExprStackPos(prevLetExprStart);
2512 }
2513 result = genExpr(tree.expr, tree.expr.type).load();
2514 code.endScopes(limit);
2515 }
2516
2517 private void generateReferencesToPrunedTree(ClassSymbol classSymbol) {
2518 List<JCTree> prunedInfo = lower.prunedTree.get(classSymbol);
2519 if (prunedInfo != null) {
2520 for (JCTree prunedTree: prunedInfo) {
2521 prunedTree.accept(classReferenceVisitor);
2522 }
2523 }
2524 }
2525
2526 /* ************************************************************************
2527 * main method
2528 *************************************************************************/
2529
2530 /** Generate code for a class definition.
2531 * @param env The attribution environment that belongs to the
2532 * outermost class containing this class definition.
2533 * We need this for resolving some additional symbols.
2534 * @param cdef The tree representing the class definition.
2535 * @return True if code is generated with no errors.
2536 */
2537 public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
2538 try {
2539 attrEnv = env;
2540 ClassSymbol c = cdef.sym;
2541 this.toplevel = env.toplevel;
2542 this.endPosTable = toplevel.endPositions;
2543 /* method normalizeDefs() can add references to external classes into the constant pool
2544 */
2545 cdef.defs = normalizeDefs(cdef.defs, c);
2546 cdef = transValues.translateTopLevelClass(cdef, make);
2547 generateReferencesToPrunedTree(c);
2548 Env<GenContext> localEnv = new Env<>(cdef, new GenContext());
2549 localEnv.toplevel = env.toplevel;
2550 localEnv.enclClass = cdef;
2551
2552 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2553 genDef(l.head, localEnv);
2554 }
2555 if (poolWriter.size() > PoolWriter.MAX_ENTRIES) {
2556 log.error(cdef.pos(), Errors.LimitPool);
2557 nerrs++;
2558 }
2559 if (nerrs != 0) {
2560 // if errors, discard code
2561 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2562 if (l.head.hasTag(METHODDEF))
2563 ((JCMethodDecl) l.head).sym.code = null;
2564 }
2565 }
2566 cdef.defs = List.nil(); // discard trees
2567 return nerrs == 0;
2568 } finally {
2569 // note: this method does NOT support recursion.
2570 attrEnv = null;
2571 this.env = null;
2572 toplevel = null;
2573 endPosTable = null;
2574 nerrs = 0;
2575 qualifiedSymbolCache.clear();
2576 }
2577 }
2578
2579 /* ************************************************************************
2580 * Auxiliary classes
2581 *************************************************************************/
2582
2583 /** An abstract class for finalizer generation.
2584 */
2585 abstract class GenFinalizer {
2586 /** Generate code to clean up when unwinding. */
2587 abstract void gen();
2588
2589 /** Generate code to clean up at last. */
2590 abstract void genLast();
2591
2592 /** Does this finalizer have some nontrivial cleanup to perform? */
2593 boolean hasFinalizer() { return true; }
2594
2595 /** Should be invoked after the try's body has been visited. */
2596 void afterBody() {}
2597 }
2598
2599 /** code generation contexts,
2600 * to be used as type parameter for environments.
2601 */
2602 static class GenContext {
2603
2604 /** A chain for all unresolved jumps that exit the current environment.
2605 */
2606 Chain exit = null;
2607
2608 /** A chain for all unresolved jumps that continue in the
2609 * current environment.
2610 */
2611 Chain cont = null;
2612
2613 /** A closure that generates the finalizer of the current environment.
2614 * Only set for Synchronized and Try contexts.
2615 */
2616 GenFinalizer finalize = null;
2617
2618 /** Is this a switch statement? If so, allocate registers
2619 * even when the variable declaration is unreachable.
2620 */
2621 boolean isSwitch = false;
2622
2623 /** A list buffer containing all gaps in the finalizer range,
2624 * where a catch all exception should not apply.
2625 */
2626 ListBuffer<Integer> gaps = null;
2627
2628 /** Add given chain to exit chain.
2629 */
2630 void addExit(Chain c) {
2631 exit = Code.mergeChains(c, exit);
2632 }
2633
2634 /** Add given chain to cont chain.
2635 */
2636 void addCont(Chain c) {
2637 cont = Code.mergeChains(c, cont);
2638 }
2639 }
2640
2641 }