1 /*
2 * Copyright (c) 1999, 2016, 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 com.sun.tools.javac.util.*;
29 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
30 import com.sun.tools.javac.util.List;
31 import com.sun.tools.javac.code.*;
32 import com.sun.tools.javac.code.Attribute.TypeCompound;
33 import com.sun.tools.javac.code.Symbol.VarSymbol;
34 import com.sun.tools.javac.comp.*;
35 import com.sun.tools.javac.tree.*;
36
37 import com.sun.tools.javac.code.Symbol.*;
38 import com.sun.tools.javac.code.Type.*;
39 import com.sun.tools.javac.jvm.Code.*;
40 import com.sun.tools.javac.jvm.Items.*;
41 import com.sun.tools.javac.tree.EndPosTable;
42 import com.sun.tools.javac.tree.JCTree.*;
43
44 import static com.sun.tools.javac.code.Flags.*;
45 import static com.sun.tools.javac.code.Kinds.Kind.*;
46 import static com.sun.tools.javac.code.TypeTag.*;
47 import static com.sun.tools.javac.jvm.ByteCodes.*;
48 import static com.sun.tools.javac.jvm.CRTFlags.*;
49 import static com.sun.tools.javac.main.Option.*;
50 import static com.sun.tools.javac.tree.JCTree.Tag.*;
51
52 /** This pass maps flat Java (i.e. without inner classes) to bytecodes.
53 *
54 * <p><b>This is NOT part of any supported API.
55 * If you write code that depends on this, you do so at your own risk.
56 * This code and its internal interfaces are subject to change or
57 * deletion without notice.</b>
58 */
59 public class Gen extends JCTree.Visitor {
60 protected static final Context.Key<Gen> genKey = new Context.Key<>();
61
62 private final Log log;
63 private final Symtab syms;
64 private final Check chk;
65 private final Resolve rs;
66 private final TreeMaker make;
67 private final Names names;
68 private final Target target;
69 private Name accessDollar;
70 private final Types types;
71 private final Lower lower;
72 private final Flow flow;
73 private final Annotate annotate;
74 private final StringConcat concat;
75
76 /** Format of stackmap tables to be generated. */
77 private final Code.StackMapFormat stackMap;
78
79 /** A type that serves as the expected type for all method expressions.
80 */
81 private final Type methodType;
82
83 /**
84 * Are we presently traversing a let expression ? Yes if depth != 0
85 */
86 private int letExprDepth;
87
88 public static Gen instance(Context context) {
89 Gen instance = context.get(genKey);
90 if (instance == null)
91 instance = new Gen(context);
92 return instance;
93 }
94
95 /** Constant pool, reset by genClass.
96 */
97 private Pool pool;
98
99 protected Gen(Context context) {
100 context.put(genKey, this);
101
102 names = Names.instance(context);
103 log = Log.instance(context);
104 syms = Symtab.instance(context);
105 chk = Check.instance(context);
106 rs = Resolve.instance(context);
107 make = TreeMaker.instance(context);
108 target = Target.instance(context);
109 types = Types.instance(context);
110 concat = StringConcat.instance(context);
111
112 methodType = new MethodType(null, null, null, syms.methodClass);
113 accessDollar = names.
114 fromString("access" + target.syntheticNameChar());
115 flow = Flow.instance(context);
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("debugcode");
128 allowBetterNullChecks = target.hasObjects();
129 pool = new Pool(types);
130
131 // ignore cldc because we cannot have both stackmap formats
132 this.stackMap = StackMapFormat.JSR202;
133 annotate = Annotate.instance(context);
134 }
135
136 /** Switches
137 */
138 private final boolean lineDebugInfo;
139 private final boolean varDebugInfo;
140 private final boolean genCrt;
141 private final boolean debugCode;
142 private final boolean allowBetterNullChecks;
143
144 /** Code buffer, set by genMethod.
145 */
146 private Code code;
147
148 /** Items structure, set by genMethod.
149 */
150 private Items items;
151
152 /** Environment for symbol lookup, set by genClass
153 */
154 private Env<AttrContext> attrEnv;
155
156 /** The top level tree.
157 */
158 private JCCompilationUnit toplevel;
159
160 /** The number of code-gen errors in this class.
161 */
162 private int nerrs = 0;
163
164 /** An object containing mappings of syntax trees to their
165 * ending source positions.
166 */
167 EndPosTable endPosTable;
168
169 /** Generate code to load an integer constant.
170 * @param n The integer to be loaded.
171 */
172 void loadIntConst(int n) {
173 items.makeImmediateItem(syms.intType, n).load();
174 }
175
176 /** The opcode that loads a zero constant of a given type code.
177 * @param tc The given type code (@see ByteCode).
178 */
179 public static int zero(int tc) {
180 switch(tc) {
181 case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
182 return iconst_0;
183 case LONGcode:
184 return lconst_0;
185 case FLOATcode:
186 return fconst_0;
187 case DOUBLEcode:
188 return dconst_0;
189 default:
190 throw new AssertionError("zero");
191 }
192 }
193
194 /** The opcode that loads a one constant of a given type code.
195 * @param tc The given type code (@see ByteCode).
196 */
197 public static int one(int tc) {
198 return zero(tc) + 1;
199 }
200
201 /** Generate code to load -1 of the given type code (either int or long).
202 * @param tc The given type code (@see ByteCode).
203 */
204 void emitMinusOne(int tc) {
205 if (tc == LONGcode) {
206 items.makeImmediateItem(syms.longType, new Long(-1)).load();
207 } else {
208 code.emitop0(iconst_m1);
209 }
210 }
211
212 /** Construct a symbol to reflect the qualifying type that should
213 * appear in the byte code as per JLS 13.1.
214 *
215 * For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except
216 * for those cases where we need to work around VM bugs).
217 *
218 * For {@literal target <= 1.1}: If qualified variable or method is defined in a
219 * non-accessible class, clone it with the qualifier class as owner.
220 *
221 * @param sym The accessed symbol
222 * @param site The qualifier's type.
223 */
224 Symbol binaryQualifier(Symbol sym, Type site) {
225
226 if (site.hasTag(ARRAY)) {
227 if (sym == syms.lengthVar ||
228 sym.owner != syms.arrayClass)
229 return sym;
230 // array clone can be qualified by the array type in later targets
231 Symbol qualifier = new ClassSymbol(Flags.PUBLIC, site.tsym.name,
232 site, syms.noSymbol);
233 return sym.clone(qualifier);
234 }
235
236 if (sym.owner == site.tsym ||
237 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
238 return sym;
239 }
240
241 // leave alone methods inherited from Object
242 // JLS 13.1.
243 if (sym.owner == syms.objectType.tsym)
244 return sym;
245
246 return sym.clone(site.tsym);
247 }
248
249 /** Insert a reference to given type in the constant pool,
250 * checking for an array with too many dimensions;
251 * return the reference's index.
252 * @param type The type for which a reference is inserted.
253 */
254 int makeRef(DiagnosticPosition pos, Type type) {
255 checkDimension(pos, type);
256 if (type.isAnnotated()) {
257 return pool.put((Object)type);
258 } else {
259 return pool.put(type.hasTag(CLASS) ? (Object)type.tsym : (Object)type);
260 }
261 }
262
263 /** Check if the given type is an array with too many dimensions.
264 */
265 private void checkDimension(DiagnosticPosition pos, Type t) {
266 switch (t.getTag()) {
267 case METHOD:
268 checkDimension(pos, t.getReturnType());
269 for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
270 checkDimension(pos, args.head);
271 break;
272 case ARRAY:
273 if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
274 log.error(pos, "limit.dimensions");
275 nerrs++;
276 }
277 break;
278 default:
279 break;
280 }
281 }
282
283 /** Create a tempory variable.
284 * @param type The variable's type.
285 */
286 LocalItem makeTemp(Type type) {
287 VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
288 names.empty,
289 type,
290 env.enclMethod.sym);
291 code.newLocal(v);
292 return items.makeLocalItem(v);
293 }
294
295 /** Generate code to call a non-private method or constructor.
296 * @param pos Position to be used for error reporting.
297 * @param site The type of which the method is a member.
298 * @param name The method's name.
299 * @param argtypes The method's argument types.
300 * @param isStatic A flag that indicates whether we call a
301 * static or instance method.
302 */
303 void callMethod(DiagnosticPosition pos,
304 Type site, Name name, List<Type> argtypes,
305 boolean isStatic) {
306 Symbol msym = rs.
307 resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
308 if (isStatic) items.makeStaticItem(msym).invoke();
309 else items.makeMemberItem(msym, name == names.init).invoke();
310 }
311
312 /** Is the given method definition an access method
313 * resulting from a qualified super? This is signified by an odd
314 * access code.
315 */
316 private boolean isAccessSuper(JCMethodDecl enclMethod) {
317 return
318 (enclMethod.mods.flags & SYNTHETIC) != 0 &&
319 isOddAccessName(enclMethod.name);
320 }
321
322 /** Does given name start with "access$" and end in an odd digit?
323 */
324 private boolean isOddAccessName(Name name) {
325 return
326 name.startsWith(accessDollar) &&
327 (name.getByteAt(name.getByteLength() - 1) & 1) == 1;
328 }
329
330 /* ************************************************************************
331 * Non-local exits
332 *************************************************************************/
333
334 /** Generate code to invoke the finalizer associated with given
335 * environment.
336 * Any calls to finalizers are appended to the environments `cont' chain.
337 * Mark beginning of gap in catch all range for finalizer.
338 */
339 void genFinalizer(Env<GenContext> env) {
340 if (code.isAlive() && env.info.finalize != null)
341 env.info.finalize.gen();
342 }
343
344 /** Generate code to call all finalizers of structures aborted by
345 * a non-local
346 * exit. Return target environment of the non-local exit.
347 * @param target The tree representing the structure that's aborted
348 * @param env The environment current at the non-local exit.
349 */
350 Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
351 Env<GenContext> env1 = env;
352 while (true) {
353 genFinalizer(env1);
354 if (env1.tree == target) break;
355 env1 = env1.next;
356 }
357 return env1;
358 }
359
360 /** Mark end of gap in catch-all range for finalizer.
361 * @param env the environment which might contain the finalizer
362 * (if it does, env.info.gaps != null).
363 */
364 void endFinalizerGap(Env<GenContext> env) {
365 if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
366 env.info.gaps.append(code.curCP());
367 }
368
369 /** Mark end of all gaps in catch-all ranges for finalizers of environments
370 * lying between, and including to two environments.
371 * @param from the most deeply nested environment to mark
372 * @param to the least deeply nested environment to mark
373 */
374 void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
375 Env<GenContext> last = null;
376 while (last != to) {
377 endFinalizerGap(from);
378 last = from;
379 from = from.next;
380 }
381 }
382
383 /** Do any of the structures aborted by a non-local exit have
384 * finalizers that require an empty stack?
385 * @param target The tree representing the structure that's aborted
386 * @param env The environment current at the non-local exit.
387 */
388 boolean hasFinally(JCTree target, Env<GenContext> env) {
389 while (env.tree != target) {
390 if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
391 return true;
392 env = env.next;
393 }
394 return false;
395 }
396
397 /* ************************************************************************
398 * Normalizing class-members.
399 *************************************************************************/
400
401 /** Distribute member initializer code into constructors and {@code <clinit>}
402 * method.
403 * @param defs The list of class member declarations.
404 * @param c The enclosing class.
405 */
406 List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
407 ListBuffer<JCStatement> initCode = new ListBuffer<>();
408 ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<>();
409 ListBuffer<JCStatement> clinitCode = new ListBuffer<>();
410 ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<>();
411 ListBuffer<JCTree> methodDefs = new ListBuffer<>();
412 // Sort definitions into three listbuffers:
413 // - initCode for instance initializers
414 // - clinitCode for class initializers
415 // - methodDefs for method definitions
416 for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
417 JCTree def = l.head;
418 switch (def.getTag()) {
419 case BLOCK:
420 JCBlock block = (JCBlock)def;
421 if ((block.flags & STATIC) != 0)
422 clinitCode.append(block);
423 else if ((block.flags & SYNTHETIC) == 0)
424 initCode.append(block);
425 break;
426 case METHODDEF:
427 methodDefs.append(def);
428 break;
429 case VARDEF:
430 JCVariableDecl vdef = (JCVariableDecl) def;
431 VarSymbol sym = vdef.sym;
432 checkDimension(vdef.pos(), sym.type);
433 if (vdef.init != null) {
434 if ((sym.flags() & STATIC) == 0) {
435 // Always initialize instance variables.
436 JCStatement init = make.at(vdef.pos()).
437 Assignment(sym, vdef.init);
438 initCode.append(init);
439 endPosTable.replaceTree(vdef, init);
440 initTAs.addAll(getAndRemoveNonFieldTAs(sym));
441 } else if (sym.getConstValue() == null) {
442 // Initialize class (static) variables only if
443 // they are not compile-time constants.
444 JCStatement init = make.at(vdef.pos).
445 Assignment(sym, vdef.init);
446 clinitCode.append(init);
447 endPosTable.replaceTree(vdef, init);
448 clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
449 } else {
450 checkStringConstant(vdef.init.pos(), sym.getConstValue());
451 /* if the init contains a reference to an external class, add it to the
452 * constant's pool
453 */
454 vdef.init.accept(classReferenceVisitor);
455 }
456 }
457 break;
458 default:
459 Assert.error();
460 }
461 }
462 // Insert any instance initializers into all constructors.
463 if (initCode.length() != 0) {
464 List<JCStatement> inits = initCode.toList();
465 initTAs.addAll(c.getInitTypeAttributes());
466 List<Attribute.TypeCompound> initTAlist = initTAs.toList();
467 for (JCTree t : methodDefs) {
468 normalizeMethod((JCMethodDecl)t, inits, initTAlist);
469 }
470 }
471 // If there are class initializers, create a <clinit> method
472 // that contains them as its body.
473 if (clinitCode.length() != 0) {
474 MethodSymbol clinit = new MethodSymbol(
475 STATIC | (c.flags() & STRICTFP),
476 names.clinit,
477 new MethodType(
478 List.<Type>nil(), syms.voidType,
479 List.<Type>nil(), syms.methodClass),
480 c);
481 c.members().enter(clinit);
482 List<JCStatement> clinitStats = clinitCode.toList();
483 JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
484 block.endpos = TreeInfo.endPos(clinitStats.last());
485 methodDefs.append(make.MethodDef(clinit, block));
486
487 if (!clinitTAs.isEmpty())
488 clinit.appendUniqueTypeAttributes(clinitTAs.toList());
489 if (!c.getClassInitTypeAttributes().isEmpty())
490 clinit.appendUniqueTypeAttributes(c.getClassInitTypeAttributes());
491 }
492 // Return all method definitions.
493 return methodDefs.toList();
494 }
495
496 private List<Attribute.TypeCompound> getAndRemoveNonFieldTAs(VarSymbol sym) {
497 List<TypeCompound> tas = sym.getRawTypeAttributes();
498 ListBuffer<Attribute.TypeCompound> fieldTAs = new ListBuffer<>();
499 ListBuffer<Attribute.TypeCompound> nonfieldTAs = new ListBuffer<>();
500 for (TypeCompound ta : tas) {
501 Assert.check(ta.getPosition().type != TargetType.UNKNOWN);
502 if (ta.getPosition().type == TargetType.FIELD) {
503 fieldTAs.add(ta);
504 } else {
505 nonfieldTAs.add(ta);
506 }
507 }
508 sym.setTypeAttributes(fieldTAs.toList());
509 return nonfieldTAs.toList();
510 }
511
512 /** Check a constant value and report if it is a string that is
513 * too large.
514 */
515 private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
516 if (nerrs != 0 || // only complain about a long string once
517 constValue == null ||
518 !(constValue instanceof String) ||
519 ((String)constValue).length() < Pool.MAX_STRING_LENGTH)
520 return;
521 log.error(pos, "limit.string");
522 nerrs++;
523 }
524
525 /** Insert instance initializer code into initial constructor.
526 * @param md The tree potentially representing a
527 * constructor's definition.
528 * @param initCode The list of instance initializer statements.
529 * @param initTAs Type annotations from the initializer expression.
530 */
531 void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<TypeCompound> initTAs) {
532 if (md.name == names.init && TreeInfo.isInitialConstructor(md)) {
533 // We are seeing a constructor that does not call another
534 // constructor of the same class.
535 List<JCStatement> stats = md.body.stats;
536 ListBuffer<JCStatement> newstats = new ListBuffer<>();
537
538 if (stats.nonEmpty()) {
539 // Copy initializers of synthetic variables generated in
540 // the translation of inner classes.
541 while (TreeInfo.isSyntheticInit(stats.head)) {
542 newstats.append(stats.head);
543 stats = stats.tail;
544 }
545 // Copy superclass constructor call
546 newstats.append(stats.head);
547 stats = stats.tail;
548 // Copy remaining synthetic initializers.
549 while (stats.nonEmpty() &&
550 TreeInfo.isSyntheticInit(stats.head)) {
551 newstats.append(stats.head);
552 stats = stats.tail;
553 }
554 // Now insert the initializer code.
555 newstats.appendList(initCode);
556 // And copy all remaining statements.
557 while (stats.nonEmpty()) {
558 newstats.append(stats.head);
559 stats = stats.tail;
560 }
561 }
562 md.body.stats = newstats.toList();
563 if (md.body.endpos == Position.NOPOS)
564 md.body.endpos = TreeInfo.endPos(md.body.stats.last());
565
566 md.sym.appendUniqueTypeAttributes(initTAs);
567 }
568 }
569
570 /* ************************************************************************
571 * Traversal methods
572 *************************************************************************/
573
574 /** Visitor argument: The current environment.
575 */
576 Env<GenContext> env;
577
578 /** Visitor argument: The expected type (prototype).
579 */
580 Type pt;
581
582 /** Visitor result: The item representing the computed value.
583 */
584 Item result;
585
586 /** Visitor method: generate code for a definition, catching and reporting
587 * any completion failures.
588 * @param tree The definition to be visited.
589 * @param env The environment current at the definition.
590 */
591 public void genDef(JCTree tree, Env<GenContext> env) {
592 Env<GenContext> prevEnv = this.env;
593 try {
594 this.env = env;
595 tree.accept(this);
596 } catch (CompletionFailure ex) {
597 chk.completionError(tree.pos(), ex);
598 } finally {
599 this.env = prevEnv;
600 }
601 }
602
603 /** Derived visitor method: check whether CharacterRangeTable
604 * should be emitted, if so, put a new entry into CRTable
605 * and call method to generate bytecode.
606 * If not, just call method to generate bytecode.
607 * @see #genStat(JCTree, Env)
608 *
609 * @param tree The tree to be visited.
610 * @param env The environment to use.
611 * @param crtFlags The CharacterRangeTable flags
612 * indicating type of the entry.
613 */
614 public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
615 if (!genCrt) {
616 genStat(tree, env);
617 return;
618 }
619 int startpc = code.curCP();
620 genStat(tree, env);
621 if (tree.hasTag(Tag.BLOCK)) crtFlags |= CRT_BLOCK;
622 code.crt.put(tree, crtFlags, startpc, code.curCP());
623 }
624
625 /** Derived visitor method: generate code for a statement.
626 */
627 public void genStat(JCTree tree, Env<GenContext> env) {
628 if (code.isAlive()) {
629 code.statBegin(tree.pos);
630 genDef(tree, env);
631 } else if (env.info.isSwitch && tree.hasTag(VARDEF)) {
632 // variables whose declarations are in a switch
633 // can be used even if the decl is unreachable.
634 code.newLocal(((JCVariableDecl) tree).sym);
635 }
636 }
637
638 /** Derived visitor method: check whether CharacterRangeTable
639 * should be emitted, if so, put a new entry into CRTable
640 * and call method to generate bytecode.
641 * If not, just call method to generate bytecode.
642 * @see #genStats(List, Env)
643 *
644 * @param trees The list of trees to be visited.
645 * @param env The environment to use.
646 * @param crtFlags The CharacterRangeTable flags
647 * indicating type of the entry.
648 */
649 public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
650 if (!genCrt) {
651 genStats(trees, env);
652 return;
653 }
654 if (trees.length() == 1) { // mark one statement with the flags
655 genStat(trees.head, env, crtFlags | CRT_STATEMENT);
656 } else {
657 int startpc = code.curCP();
658 genStats(trees, env);
659 code.crt.put(trees, crtFlags, startpc, code.curCP());
660 }
661 }
662
663 /** Derived visitor method: generate code for a list of statements.
664 */
665 public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
666 for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
667 genStat(l.head, env, CRT_STATEMENT);
668 }
669
670 /** Derived visitor method: check whether CharacterRangeTable
671 * should be emitted, if so, put a new entry into CRTable
672 * and call method to generate bytecode.
673 * If not, just call method to generate bytecode.
674 * @see #genCond(JCTree,boolean)
675 *
676 * @param tree The tree to be visited.
677 * @param crtFlags The CharacterRangeTable flags
678 * indicating type of the entry.
679 */
680 public CondItem genCond(JCTree tree, int crtFlags) {
681 if (!genCrt) return genCond(tree, false);
682 int startpc = code.curCP();
683 CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
684 code.crt.put(tree, crtFlags, startpc, code.curCP());
685 return item;
686 }
687
688 /** Derived visitor method: generate code for a boolean
689 * expression in a control-flow context.
690 * @param _tree The expression to be visited.
691 * @param markBranches The flag to indicate that the condition is
692 * a flow controller so produced conditions
693 * should contain a proper tree to generate
694 * CharacterRangeTable branches for them.
695 */
696 public CondItem genCond(JCTree _tree, boolean markBranches) {
697 JCTree inner_tree = TreeInfo.skipParens(_tree);
698 if (inner_tree.hasTag(CONDEXPR)) {
699 JCConditional tree = (JCConditional)inner_tree;
700 CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
701 if (cond.isTrue()) {
702 code.resolve(cond.trueJumps);
703 CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
704 if (markBranches) result.tree = tree.truepart;
705 return result;
706 }
707 if (cond.isFalse()) {
708 code.resolve(cond.falseJumps);
709 CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
710 if (markBranches) result.tree = tree.falsepart;
711 return result;
712 }
713 Chain secondJumps = cond.jumpFalse();
714 code.resolve(cond.trueJumps);
715 CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
716 if (markBranches) first.tree = tree.truepart;
717 Chain falseJumps = first.jumpFalse();
718 code.resolve(first.trueJumps);
719 Chain trueJumps = code.branch(goto_);
720 code.resolve(secondJumps);
721 CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
722 CondItem result = items.makeCondItem(second.opcode,
723 Code.mergeChains(trueJumps, second.trueJumps),
724 Code.mergeChains(falseJumps, second.falseJumps));
725 if (markBranches) result.tree = tree.falsepart;
726 return result;
727 } else {
728 CondItem result = genExpr(_tree, syms.booleanType).mkCond();
729 if (markBranches) result.tree = _tree;
730 return result;
731 }
732 }
733
734 public Code getCode() {
735 return code;
736 }
737
738 public Items getItems() {
739 return items;
740 }
741
742 public Env<AttrContext> getAttrEnv() {
743 return attrEnv;
744 }
745
746 /** Visitor class for expressions which might be constant expressions.
747 * This class is a subset of TreeScanner. Intended to visit trees pruned by
748 * Lower as long as constant expressions looking for references to any
749 * ClassSymbol. Any such reference will be added to the constant pool so
750 * automated tools can detect class dependencies better.
751 */
752 class ClassReferenceVisitor extends JCTree.Visitor {
753
754 @Override
755 public void visitTree(JCTree tree) {}
756
757 @Override
758 public void visitBinary(JCBinary tree) {
759 tree.lhs.accept(this);
760 tree.rhs.accept(this);
761 }
762
763 @Override
764 public void visitSelect(JCFieldAccess tree) {
765 if (tree.selected.type.hasTag(CLASS)) {
766 makeRef(tree.selected.pos(), tree.selected.type);
767 }
768 }
769
770 @Override
771 public void visitIdent(JCIdent tree) {
772 if (tree.sym.owner instanceof ClassSymbol) {
773 pool.put(tree.sym.owner);
774 }
775 }
776
777 @Override
778 public void visitConditional(JCConditional tree) {
779 tree.cond.accept(this);
780 tree.truepart.accept(this);
781 tree.falsepart.accept(this);
782 }
783
784 @Override
785 public void visitUnary(JCUnary tree) {
786 tree.arg.accept(this);
787 }
788
789 @Override
790 public void visitParens(JCParens tree) {
791 tree.expr.accept(this);
792 }
793
794 @Override
795 public void visitTypeCast(JCTypeCast tree) {
796 tree.expr.accept(this);
797 }
798 }
799
800 private ClassReferenceVisitor classReferenceVisitor = new ClassReferenceVisitor();
801
802 /** Visitor method: generate code for an expression, catching and reporting
803 * any completion failures.
804 * @param tree The expression to be visited.
805 * @param pt The expression's expected type (proto-type).
806 */
807 public Item genExpr(JCTree tree, Type pt) {
808 Type prevPt = this.pt;
809 try {
810 if (tree.type.constValue() != null) {
811 // Short circuit any expressions which are constants
812 tree.accept(classReferenceVisitor);
813 checkStringConstant(tree.pos(), tree.type.constValue());
814 result = items.makeImmediateItem(tree.type, tree.type.constValue());
815 } else {
816 this.pt = pt;
817 tree.accept(this);
818 }
819 return result.coerce(pt);
820 } catch (CompletionFailure ex) {
821 chk.completionError(tree.pos(), ex);
822 code.state.stacksize = 1;
823 return items.makeStackItem(pt);
824 } finally {
825 this.pt = prevPt;
826 }
827 }
828
829 /** Derived visitor method: generate code for a list of method arguments.
830 * @param trees The argument expressions to be visited.
831 * @param pts The expression's expected types (i.e. the formal parameter
832 * types of the invoked method).
833 */
834 public void genArgs(List<JCExpression> trees, List<Type> pts) {
835 for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail) {
836 genExpr(l.head, pts.head).load();
837 pts = pts.tail;
838 }
839 // require lists be of same length
840 Assert.check(pts.isEmpty());
841 }
842
843 /* ************************************************************************
844 * Visitor methods for statements and definitions
845 *************************************************************************/
846
847 /** Thrown when the byte code size exceeds limit.
848 */
849 public static class CodeSizeOverflow extends RuntimeException {
850 private static final long serialVersionUID = 0;
851 public CodeSizeOverflow() {}
852 }
853
854 public void visitMethodDef(JCMethodDecl tree) {
855 // Create a new local environment that points pack at method
856 // definition.
857 Env<GenContext> localEnv = env.dup(tree);
858 localEnv.enclMethod = tree;
859 // The expected type of every return statement in this method
860 // is the method's return type.
861 this.pt = tree.sym.erasure(types).getReturnType();
862
863 checkDimension(tree.pos(), tree.sym.erasure(types));
864 genMethod(tree, localEnv, false);
865 }
866 //where
867 /** Generate code for a method.
868 * @param tree The tree representing the method definition.
869 * @param env The environment current for the method body.
870 * @param fatcode A flag that indicates whether all jumps are
871 * within 32K. We first invoke this method under
872 * the assumption that fatcode == false, i.e. all
873 * jumps are within 32K. If this fails, fatcode
874 * is set to true and we try again.
875 */
876 void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
877 MethodSymbol meth = tree.sym;
878 int extras = 0;
879 // Count up extra parameters
880 if (meth.isConstructor()) {
881 extras++;
882 if (meth.enclClass().isInner() &&
883 !meth.enclClass().isStatic()) {
884 extras++;
885 }
886 } else if ((tree.mods.flags & STATIC) == 0) {
887 extras++;
888 }
889 // System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
890 if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
891 ClassFile.MAX_PARAMETERS) {
892 log.error(tree.pos(), "limit.parameters");
893 nerrs++;
894 }
895
896 else if (tree.body != null) {
897 // Create a new code structure and initialize it.
898 int startpcCrt = initCode(tree, env, fatcode);
899
900 try {
901 genStat(tree.body, env);
902 } catch (CodeSizeOverflow e) {
903 // Failed due to code limit, try again with jsr/ret
904 startpcCrt = initCode(tree, env, fatcode);
905 genStat(tree.body, env);
906 }
907
908 if (code.state.stacksize != 0) {
909 log.error(tree.body.pos(), "stack.sim.error", tree);
910 throw new AssertionError();
911 }
912
913 // If last statement could complete normally, insert a
914 // return at the end.
915 if (code.isAlive()) {
916 code.statBegin(TreeInfo.endPos(tree.body));
917 if (env.enclMethod == null ||
918 env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
919 code.emitop0(return_);
920 } else {
921 // sometime dead code seems alive (4415991);
922 // generate a small loop instead
923 int startpc = code.entryPoint();
924 CondItem c = items.makeCondItem(goto_);
925 code.resolve(c.jumpTrue(), startpc);
926 }
927 }
928 if (genCrt)
929 code.crt.put(tree.body,
930 CRT_BLOCK,
931 startpcCrt,
932 code.curCP());
933
934 code.endScopes(0);
935
936 // If we exceeded limits, panic
937 if (code.checkLimits(tree.pos(), log)) {
938 nerrs++;
939 return;
940 }
941
942 // If we generated short code but got a long jump, do it again
943 // with fatCode = true.
944 if (!fatcode && code.fatcode) genMethod(tree, env, true);
945
946 // Clean up
947 if(stackMap == StackMapFormat.JSR202) {
948 code.lastFrame = null;
949 code.frameBeforeLast = null;
950 }
951
952 // Compress exception table
953 code.compressCatchTable();
954
955 // Fill in type annotation positions for exception parameters
956 code.fillExceptionParameterPositions();
957 }
958 }
959
960 private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
961 MethodSymbol meth = tree.sym;
962
963 // Create a new code structure.
964 meth.code = code = new Code(meth,
965 fatcode,
966 lineDebugInfo ? toplevel.lineMap : null,
967 varDebugInfo,
968 stackMap,
969 debugCode,
970 genCrt ? new CRTable(tree, env.toplevel.endPositions)
971 : null,
972 syms,
973 types,
974 pool);
975 items = new Items(pool, code, syms, types);
976 if (code.debugCode) {
977 System.err.println(meth + " for body " + tree);
978 }
979
980 // If method is not static, create a new local variable address
981 // for `this'.
982 if ((tree.mods.flags & STATIC) == 0) {
983 Type selfType = meth.owner.type;
984 if (meth.isConstructor() && selfType != syms.objectType)
985 selfType = UninitializedType.uninitializedThis(selfType);
986 code.setDefined(
987 code.newLocal(
988 new VarSymbol(FINAL, names._this, selfType, meth.owner)));
989 }
990
991 // Mark all parameters as defined from the beginning of
992 // the method.
993 for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
994 checkDimension(l.head.pos(), l.head.sym.type);
995 code.setDefined(code.newLocal(l.head.sym));
996 }
997
998 // Get ready to generate code for method body.
999 int startpcCrt = genCrt ? code.curCP() : 0;
1000 code.entryPoint();
1001
1002 // Suppress initial stackmap
1003 code.pendingStackMap = false;
1004
1005 return startpcCrt;
1006 }
1007
1008 public void visitVarDef(JCVariableDecl tree) {
1009 VarSymbol v = tree.sym;
1010 code.newLocal(v);
1011 if (tree.init != null) {
1012 checkStringConstant(tree.init.pos(), v.getConstValue());
1013 if (v.getConstValue() == null || varDebugInfo) {
1014 Assert.check(letExprDepth != 0 || code.state.stacksize == 0);
1015 genExpr(tree.init, v.erasure(types)).load();
1016 items.makeLocalItem(v).store();
1017 Assert.check(letExprDepth != 0 || code.state.stacksize == 0);
1018 }
1019 }
1020 checkDimension(tree.pos(), v.type);
1021 }
1022
1023 public void visitSkip(JCSkip tree) {
1024 }
1025
1026 public void visitBlock(JCBlock tree) {
1027 int limit = code.nextreg;
1028 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1029 genStats(tree.stats, localEnv);
1030 // End the scope of all block-local variables in variable info.
1031 if (!env.tree.hasTag(METHODDEF)) {
1032 code.statBegin(tree.endpos);
1033 code.endScopes(limit);
1034 code.pendingStatPos = Position.NOPOS;
1035 }
1036 }
1037
1038 public void visitDoLoop(JCDoWhileLoop tree) {
1039 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), false);
1040 }
1041
1042 public void visitWhileLoop(JCWhileLoop tree) {
1043 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), true);
1044 }
1045
1046 public void visitForLoop(JCForLoop tree) {
1047 int limit = code.nextreg;
1048 genStats(tree.init, env);
1049 genLoop(tree, tree.body, tree.cond, tree.step, true);
1050 code.endScopes(limit);
1051 }
1052 //where
1053 /** Generate code for a loop.
1054 * @param loop The tree representing the loop.
1055 * @param body The loop's body.
1056 * @param cond The loop's controling condition.
1057 * @param step "Step" statements to be inserted at end of
1058 * each iteration.
1059 * @param testFirst True if the loop test belongs before the body.
1060 */
1061 private void genLoop(JCStatement loop,
1062 JCStatement body,
1063 JCExpression cond,
1064 List<JCExpressionStatement> step,
1065 boolean testFirst) {
1066 Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1067 int startpc = code.entryPoint();
1068 if (testFirst) { //while or for loop
1069 CondItem c;
1070 if (cond != null) {
1071 code.statBegin(cond.pos);
1072 Assert.check(code.state.stacksize == 0);
1073 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1074 } else {
1075 c = items.makeCondItem(goto_);
1076 }
1077 Chain loopDone = c.jumpFalse();
1078 code.resolve(c.trueJumps);
1079 Assert.check(code.state.stacksize == 0);
1080 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1081 code.resolve(loopEnv.info.cont);
1082 genStats(step, loopEnv);
1083 code.resolve(code.branch(goto_), startpc);
1084 code.resolve(loopDone);
1085 } else {
1086 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1087 code.resolve(loopEnv.info.cont);
1088 genStats(step, loopEnv);
1089 CondItem c;
1090 if (cond != null) {
1091 code.statBegin(cond.pos);
1092 Assert.check(code.state.stacksize == 0);
1093 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1094 } else {
1095 c = items.makeCondItem(goto_);
1096 }
1097 code.resolve(c.jumpTrue(), startpc);
1098 Assert.check(code.state.stacksize == 0);
1099 code.resolve(c.falseJumps);
1100 }
1101 Chain exit = loopEnv.info.exit;
1102 if (exit != null) {
1103 code.resolve(exit);
1104 exit.state.defined.excludeFrom(code.nextreg);
1105 }
1106 }
1107
1108 public void visitForeachLoop(JCEnhancedForLoop tree) {
1109 throw new AssertionError(); // should have been removed by Lower.
1110 }
1111
1112 public void visitLabelled(JCLabeledStatement tree) {
1113 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1114 genStat(tree.body, localEnv, CRT_STATEMENT);
1115 Chain exit = localEnv.info.exit;
1116 if (exit != null) {
1117 code.resolve(exit);
1118 exit.state.defined.excludeFrom(code.nextreg);
1119 }
1120 }
1121
1122 public void visitSwitch(JCSwitch tree) {
1123 int limit = code.nextreg;
1124 Assert.check(!tree.selector.type.hasTag(CLASS));
1125 int startpcCrt = genCrt ? code.curCP() : 0;
1126 Assert.check(code.state.stacksize == 0);
1127 Item sel = genExpr(tree.selector, syms.intType);
1128 List<JCCase> cases = tree.cases;
1129 if (cases.isEmpty()) {
1130 // We are seeing: switch <sel> {}
1131 sel.load().drop();
1132 if (genCrt)
1133 code.crt.put(TreeInfo.skipParens(tree.selector),
1134 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1135 } else {
1136 // We are seeing a nonempty switch.
1137 sel.load();
1138 if (genCrt)
1139 code.crt.put(TreeInfo.skipParens(tree.selector),
1140 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1141 Env<GenContext> switchEnv = env.dup(tree, new GenContext());
1142 switchEnv.info.isSwitch = true;
1143
1144 // Compute number of labels and minimum and maximum label values.
1145 // For each case, store its label in an array.
1146 int lo = Integer.MAX_VALUE; // minimum label.
1147 int hi = Integer.MIN_VALUE; // maximum label.
1148 int nlabels = 0; // number of labels.
1149
1150 int[] labels = new int[cases.length()]; // the label array.
1151 int defaultIndex = -1; // the index of the default clause.
1152
1153 List<JCCase> l = cases;
1154 for (int i = 0; i < labels.length; i++) {
1155 if (l.head.pat != null) {
1156 int val = ((Number)l.head.pat.type.constValue()).intValue();
1157 labels[i] = val;
1158 if (val < lo) lo = val;
1159 if (hi < val) hi = val;
1160 nlabels++;
1161 } else {
1162 Assert.check(defaultIndex == -1);
1163 defaultIndex = i;
1164 }
1165 l = l.tail;
1166 }
1167
1168 // Determine whether to issue a tableswitch or a lookupswitch
1169 // instruction.
1170 long table_space_cost = 4 + ((long) hi - lo + 1); // words
1171 long table_time_cost = 3; // comparisons
1172 long lookup_space_cost = 3 + 2 * (long) nlabels;
1173 long lookup_time_cost = nlabels;
1174 int opcode =
1175 nlabels > 0 &&
1176 table_space_cost + 3 * table_time_cost <=
1177 lookup_space_cost + 3 * lookup_time_cost
1178 ?
1179 tableswitch : lookupswitch;
1180
1181 int startpc = code.curCP(); // the position of the selector operation
1182 code.emitop0(opcode);
1183 code.align(4);
1184 int tableBase = code.curCP(); // the start of the jump table
1185 int[] offsets = null; // a table of offsets for a lookupswitch
1186 code.emit4(-1); // leave space for default offset
1187 if (opcode == tableswitch) {
1188 code.emit4(lo); // minimum label
1189 code.emit4(hi); // maximum label
1190 for (long i = lo; i <= hi; i++) { // leave space for jump table
1191 code.emit4(-1);
1192 }
1193 } else {
1194 code.emit4(nlabels); // number of labels
1195 for (int i = 0; i < nlabels; i++) {
1196 code.emit4(-1); code.emit4(-1); // leave space for lookup table
1197 }
1198 offsets = new int[labels.length];
1199 }
1200 Code.State stateSwitch = code.state.dup();
1201 code.markDead();
1202
1203 // For each case do:
1204 l = cases;
1205 for (int i = 0; i < labels.length; i++) {
1206 JCCase c = l.head;
1207 l = l.tail;
1208
1209 int pc = code.entryPoint(stateSwitch);
1210 // Insert offset directly into code or else into the
1211 // offsets table.
1212 if (i != defaultIndex) {
1213 if (opcode == tableswitch) {
1214 code.put4(
1215 tableBase + 4 * (labels[i] - lo + 3),
1216 pc - startpc);
1217 } else {
1218 offsets[i] = pc - startpc;
1219 }
1220 } else {
1221 code.put4(tableBase, pc - startpc);
1222 }
1223
1224 // Generate code for the statements in this case.
1225 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1226 }
1227
1228 // Resolve all breaks.
1229 Chain exit = switchEnv.info.exit;
1230 if (exit != null) {
1231 code.resolve(exit);
1232 exit.state.defined.excludeFrom(code.nextreg);
1233 }
1234
1235 // If we have not set the default offset, we do so now.
1236 if (code.get4(tableBase) == -1) {
1237 code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
1238 }
1239
1240 if (opcode == tableswitch) {
1241 // Let any unfilled slots point to the default case.
1242 int defaultOffset = code.get4(tableBase);
1243 for (long i = lo; i <= hi; i++) {
1244 int t = (int)(tableBase + 4 * (i - lo + 3));
1245 if (code.get4(t) == -1)
1246 code.put4(t, defaultOffset);
1247 }
1248 } else {
1249 // Sort non-default offsets and copy into lookup table.
1250 if (defaultIndex >= 0)
1251 for (int i = defaultIndex; i < labels.length - 1; i++) {
1252 labels[i] = labels[i+1];
1253 offsets[i] = offsets[i+1];
1254 }
1255 if (nlabels > 0)
1256 qsort2(labels, offsets, 0, nlabels - 1);
1257 for (int i = 0; i < nlabels; i++) {
1258 int caseidx = tableBase + 8 * (i + 1);
1259 code.put4(caseidx, labels[i]);
1260 code.put4(caseidx + 4, offsets[i]);
1261 }
1262 }
1263 }
1264 code.endScopes(limit);
1265 }
1266 //where
1267 /** Sort (int) arrays of keys and values
1268 */
1269 static void qsort2(int[] keys, int[] values, int lo, int hi) {
1270 int i = lo;
1271 int j = hi;
1272 int pivot = keys[(i+j)/2];
1273 do {
1274 while (keys[i] < pivot) i++;
1275 while (pivot < keys[j]) j--;
1276 if (i <= j) {
1277 int temp1 = keys[i];
1278 keys[i] = keys[j];
1279 keys[j] = temp1;
1280 int temp2 = values[i];
1281 values[i] = values[j];
1282 values[j] = temp2;
1283 i++;
1284 j--;
1285 }
1286 } while (i <= j);
1287 if (lo < j) qsort2(keys, values, lo, j);
1288 if (i < hi) qsort2(keys, values, i, hi);
1289 }
1290
1291 public void visitSynchronized(JCSynchronized tree) {
1292 int limit = code.nextreg;
1293 // Generate code to evaluate lock and save in temporary variable.
1294 final LocalItem lockVar = makeTemp(syms.objectType);
1295 Assert.check(code.state.stacksize == 0);
1296 genExpr(tree.lock, tree.lock.type).load().duplicate();
1297 lockVar.store();
1298
1299 // Generate code to enter monitor.
1300 code.emitop0(monitorenter);
1301 code.state.lock(lockVar.reg);
1302
1303 // Generate code for a try statement with given body, no catch clauses
1304 // in a new environment with the "exit-monitor" operation as finalizer.
1305 final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
1306 syncEnv.info.finalize = new GenFinalizer() {
1307 void gen() {
1308 genLast();
1309 Assert.check(syncEnv.info.gaps.length() % 2 == 0);
1310 syncEnv.info.gaps.append(code.curCP());
1311 }
1312 void genLast() {
1313 if (code.isAlive()) {
1314 lockVar.load();
1315 code.emitop0(monitorexit);
1316 code.state.unlock(lockVar.reg);
1317 }
1318 }
1319 };
1320 syncEnv.info.gaps = new ListBuffer<>();
1321 genTry(tree.body, List.<JCCatch>nil(), syncEnv);
1322 code.endScopes(limit);
1323 }
1324
1325 public void visitTry(final JCTry tree) {
1326 // Generate code for a try statement with given body and catch clauses,
1327 // in a new environment which calls the finally block if there is one.
1328 final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
1329 final Env<GenContext> oldEnv = env;
1330 tryEnv.info.finalize = new GenFinalizer() {
1331 void gen() {
1332 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1333 tryEnv.info.gaps.append(code.curCP());
1334 genLast();
1335 }
1336 void genLast() {
1337 if (tree.finalizer != null)
1338 genStat(tree.finalizer, oldEnv, CRT_BLOCK);
1339 }
1340 boolean hasFinalizer() {
1341 return tree.finalizer != null;
1342 }
1343 };
1344 tryEnv.info.gaps = new ListBuffer<>();
1345 genTry(tree.body, tree.catchers, tryEnv);
1346 }
1347 //where
1348 /** Generate code for a try or synchronized statement
1349 * @param body The body of the try or synchronized statement.
1350 * @param catchers The lis of catch clauses.
1351 * @param env the environment current for the body.
1352 */
1353 void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1354 int limit = code.nextreg;
1355 int startpc = code.curCP();
1356 Code.State stateTry = code.state.dup();
1357 genStat(body, env, CRT_BLOCK);
1358 int endpc = code.curCP();
1359 boolean hasFinalizer =
1360 env.info.finalize != null &&
1361 env.info.finalize.hasFinalizer();
1362 List<Integer> gaps = env.info.gaps.toList();
1363 code.statBegin(TreeInfo.endPos(body));
1364 genFinalizer(env);
1365 code.statBegin(TreeInfo.endPos(env.tree));
1366 Chain exitChain = code.branch(goto_);
1367 endFinalizerGap(env);
1368 if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1369 // start off with exception on stack
1370 code.entryPoint(stateTry, l.head.param.sym.type);
1371 genCatch(l.head, env, startpc, endpc, gaps);
1372 genFinalizer(env);
1373 if (hasFinalizer || l.tail.nonEmpty()) {
1374 code.statBegin(TreeInfo.endPos(env.tree));
1375 exitChain = Code.mergeChains(exitChain,
1376 code.branch(goto_));
1377 }
1378 endFinalizerGap(env);
1379 }
1380 if (hasFinalizer) {
1381 // Create a new register segement to avoid allocating
1382 // the same variables in finalizers and other statements.
1383 code.newRegSegment();
1384
1385 // Add a catch-all clause.
1386
1387 // start off with exception on stack
1388 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1389
1390 // Register all exception ranges for catch all clause.
1391 // The range of the catch all clause is from the beginning
1392 // of the try or synchronized block until the present
1393 // code pointer excluding all gaps in the current
1394 // environment's GenContext.
1395 int startseg = startpc;
1396 while (env.info.gaps.nonEmpty()) {
1397 int endseg = env.info.gaps.next().intValue();
1398 registerCatch(body.pos(), startseg, endseg,
1399 catchallpc, 0);
1400 startseg = env.info.gaps.next().intValue();
1401 }
1402 code.statBegin(TreeInfo.finalizerPos(env.tree));
1403 code.markStatBegin();
1404
1405 Item excVar = makeTemp(syms.throwableType);
1406 excVar.store();
1407 genFinalizer(env);
1408 excVar.load();
1409 registerCatch(body.pos(), startseg,
1410 env.info.gaps.next().intValue(),
1411 catchallpc, 0);
1412 code.emitop0(athrow);
1413 code.markDead();
1414
1415 // If there are jsr's to this finalizer, ...
1416 if (env.info.cont != null) {
1417 // Resolve all jsr's.
1418 code.resolve(env.info.cont);
1419
1420 // Mark statement line number
1421 code.statBegin(TreeInfo.finalizerPos(env.tree));
1422 code.markStatBegin();
1423
1424 // Save return address.
1425 LocalItem retVar = makeTemp(syms.throwableType);
1426 retVar.store();
1427
1428 // Generate finalizer code.
1429 env.info.finalize.genLast();
1430
1431 // Return.
1432 code.emitop1w(ret, retVar.reg);
1433 code.markDead();
1434 }
1435 }
1436 // Resolve all breaks.
1437 code.resolve(exitChain);
1438
1439 code.endScopes(limit);
1440 }
1441
1442 /** Generate code for a catch clause.
1443 * @param tree The catch clause.
1444 * @param env The environment current in the enclosing try.
1445 * @param startpc Start pc of try-block.
1446 * @param endpc End pc of try-block.
1447 */
1448 void genCatch(JCCatch tree,
1449 Env<GenContext> env,
1450 int startpc, int endpc,
1451 List<Integer> gaps) {
1452 if (startpc != endpc) {
1453 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypeExprs
1454 = catchTypesWithAnnotations(tree);
1455 while (gaps.nonEmpty()) {
1456 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1457 JCExpression subCatch = subCatch1.snd;
1458 int catchType = makeRef(tree.pos(), subCatch.type);
1459 int end = gaps.head.intValue();
1460 registerCatch(tree.pos(),
1461 startpc, end, code.curCP(),
1462 catchType);
1463 for (Attribute.TypeCompound tc : subCatch1.fst) {
1464 tc.position.setCatchInfo(catchType, startpc);
1465 }
1466 }
1467 gaps = gaps.tail;
1468 startpc = gaps.head.intValue();
1469 gaps = gaps.tail;
1470 }
1471 if (startpc < endpc) {
1472 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1473 JCExpression subCatch = subCatch1.snd;
1474 int catchType = makeRef(tree.pos(), subCatch.type);
1475 registerCatch(tree.pos(),
1476 startpc, endpc, code.curCP(),
1477 catchType);
1478 for (Attribute.TypeCompound tc : subCatch1.fst) {
1479 tc.position.setCatchInfo(catchType, startpc);
1480 }
1481 }
1482 }
1483 VarSymbol exparam = tree.param.sym;
1484 code.statBegin(tree.pos);
1485 code.markStatBegin();
1486 int limit = code.nextreg;
1487 code.newLocal(exparam);
1488 items.makeLocalItem(exparam).store();
1489 code.statBegin(TreeInfo.firstStatPos(tree.body));
1490 genStat(tree.body, env, CRT_BLOCK);
1491 code.endScopes(limit);
1492 code.statBegin(TreeInfo.endPos(tree.body));
1493 }
1494 }
1495 // where
1496 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotations(JCCatch tree) {
1497 return TreeInfo.isMultiCatch(tree) ?
1498 catchTypesWithAnnotationsFromMulticatch((JCTypeUnion)tree.param.vartype, tree.param.sym.getRawTypeAttributes()) :
1499 List.of(new Pair<>(tree.param.sym.getRawTypeAttributes(), tree.param.vartype));
1500 }
1501 // where
1502 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotationsFromMulticatch(JCTypeUnion tree, List<TypeCompound> first) {
1503 List<JCExpression> alts = tree.alternatives;
1504 List<Pair<List<TypeCompound>, JCExpression>> res = List.of(new Pair<>(first, alts.head));
1505 alts = alts.tail;
1506
1507 while(alts != null && alts.head != null) {
1508 JCExpression alt = alts.head;
1509 if (alt instanceof JCAnnotatedType) {
1510 JCAnnotatedType a = (JCAnnotatedType)alt;
1511 res = res.prepend(new Pair<>(annotate.fromAnnotations(a.annotations), alt));
1512 } else {
1513 res = res.prepend(new Pair<>(List.nil(), alt));
1514 }
1515 alts = alts.tail;
1516 }
1517 return res.reverse();
1518 }
1519
1520 /** Register a catch clause in the "Exceptions" code-attribute.
1521 */
1522 void registerCatch(DiagnosticPosition pos,
1523 int startpc, int endpc,
1524 int handler_pc, int catch_type) {
1525 char startpc1 = (char)startpc;
1526 char endpc1 = (char)endpc;
1527 char handler_pc1 = (char)handler_pc;
1528 if (startpc1 == startpc &&
1529 endpc1 == endpc &&
1530 handler_pc1 == handler_pc) {
1531 code.addCatch(startpc1, endpc1, handler_pc1,
1532 (char)catch_type);
1533 } else {
1534 log.error(pos, "limit.code.too.large.for.try.stmt");
1535 nerrs++;
1536 }
1537 }
1538
1539 public void visitIf(JCIf tree) {
1540 int limit = code.nextreg;
1541 Chain thenExit = null;
1542 Assert.check(code.state.stacksize == 0);
1543 CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1544 CRT_FLOW_CONTROLLER);
1545 Chain elseChain = c.jumpFalse();
1546 Assert.check(code.state.stacksize == 0);
1547 if (!c.isFalse()) {
1548 code.resolve(c.trueJumps);
1549 genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1550 thenExit = code.branch(goto_);
1551 }
1552 if (elseChain != null) {
1553 code.resolve(elseChain);
1554 if (tree.elsepart != null) {
1555 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1556 }
1557 }
1558 code.resolve(thenExit);
1559 code.endScopes(limit);
1560 Assert.check(code.state.stacksize == 0);
1561 }
1562
1563 public void visitExec(JCExpressionStatement tree) {
1564 // Optimize x++ to ++x and x-- to --x.
1565 JCExpression e = tree.expr;
1566 switch (e.getTag()) {
1567 case POSTINC:
1568 ((JCUnary) e).setTag(PREINC);
1569 break;
1570 case POSTDEC:
1571 ((JCUnary) e).setTag(PREDEC);
1572 break;
1573 }
1574 Assert.check(code.state.stacksize == 0);
1575 genExpr(tree.expr, tree.expr.type).drop();
1576 Assert.check(code.state.stacksize == 0);
1577 }
1578
1579 public void visitBreak(JCBreak tree) {
1580 Env<GenContext> targetEnv = unwind(tree.target, env);
1581 Assert.check(code.state.stacksize == 0);
1582 targetEnv.info.addExit(code.branch(goto_));
1583 endFinalizerGaps(env, targetEnv);
1584 }
1585
1586 public void visitContinue(JCContinue tree) {
1587 Env<GenContext> targetEnv = unwind(tree.target, env);
1588 Assert.check(code.state.stacksize == 0);
1589 targetEnv.info.addCont(code.branch(goto_));
1590 endFinalizerGaps(env, targetEnv);
1591 }
1592
1593 public void visitReturn(JCReturn tree) {
1594 int limit = code.nextreg;
1595 final Env<GenContext> targetEnv;
1596
1597 /* Save and then restore the location of the return in case a finally
1598 * is expanded (with unwind()) in the middle of our bytecodes.
1599 */
1600 int tmpPos = code.pendingStatPos;
1601 if (tree.expr != null) {
1602 Assert.check(code.state.stacksize == 0);
1603 Item r = genExpr(tree.expr, pt).load();
1604 if (hasFinally(env.enclMethod, env)) {
1605 r = makeTemp(pt);
1606 r.store();
1607 }
1608 targetEnv = unwind(env.enclMethod, env);
1609 code.pendingStatPos = tmpPos;
1610 r.load();
1611 code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
1612 } else {
1613 targetEnv = unwind(env.enclMethod, env);
1614 code.pendingStatPos = tmpPos;
1615 code.emitop0(return_);
1616 }
1617 endFinalizerGaps(env, targetEnv);
1618 code.endScopes(limit);
1619 }
1620
1621 public void visitThrow(JCThrow tree) {
1622 Assert.check(code.state.stacksize == 0);
1623 genExpr(tree.expr, tree.expr.type).load();
1624 code.emitop0(athrow);
1625 Assert.check(code.state.stacksize == 0);
1626 }
1627
1628 /* ************************************************************************
1629 * Visitor methods for expressions
1630 *************************************************************************/
1631
1632 public void visitApply(JCMethodInvocation tree) {
1633 setTypeAnnotationPositions(tree.pos);
1634 // Generate code for method.
1635 Item m = genExpr(tree.meth, methodType);
1636 // Generate code for all arguments, where the expected types are
1637 // the parameters of the method's external type (that is, any implicit
1638 // outer instance of a super(...) call appears as first parameter).
1639 MethodSymbol msym = (MethodSymbol)TreeInfo.symbol(tree.meth);
1640 genArgs(tree.args,
1641 msym.externalType(types).getParameterTypes());
1642 if (!msym.isDynamic()) {
1643 code.statBegin(tree.pos);
1644 }
1645 result = m.invoke();
1646 }
1647
1648 public void visitConditional(JCConditional tree) {
1649 Chain thenExit = null;
1650 CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
1651 Chain elseChain = c.jumpFalse();
1652 if (!c.isFalse()) {
1653 code.resolve(c.trueJumps);
1654 int startpc = genCrt ? code.curCP() : 0;
1655 code.statBegin(tree.truepart.pos);
1656 genExpr(tree.truepart, pt).load();
1657 code.state.forceStackTop(tree.type);
1658 if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
1659 startpc, code.curCP());
1660 thenExit = code.branch(goto_);
1661 }
1662 if (elseChain != null) {
1663 code.resolve(elseChain);
1664 int startpc = genCrt ? code.curCP() : 0;
1665 code.statBegin(tree.falsepart.pos);
1666 genExpr(tree.falsepart, pt).load();
1667 code.state.forceStackTop(tree.type);
1668 if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
1669 startpc, code.curCP());
1670 }
1671 code.resolve(thenExit);
1672 result = items.makeStackItem(pt);
1673 }
1674
1675 private void setTypeAnnotationPositions(int treePos) {
1676 MethodSymbol meth = code.meth;
1677 boolean initOrClinit = code.meth.getKind() == javax.lang.model.element.ElementKind.CONSTRUCTOR
1678 || code.meth.getKind() == javax.lang.model.element.ElementKind.STATIC_INIT;
1679
1680 for (Attribute.TypeCompound ta : meth.getRawTypeAttributes()) {
1681 if (ta.hasUnknownPosition())
1682 ta.tryFixPosition();
1683
1684 if (ta.position.matchesPos(treePos))
1685 ta.position.updatePosOffset(code.cp);
1686 }
1687
1688 if (!initOrClinit)
1689 return;
1690
1691 for (Attribute.TypeCompound ta : meth.owner.getRawTypeAttributes()) {
1692 if (ta.hasUnknownPosition())
1693 ta.tryFixPosition();
1694
1695 if (ta.position.matchesPos(treePos))
1696 ta.position.updatePosOffset(code.cp);
1697 }
1698
1699 ClassSymbol clazz = meth.enclClass();
1700 for (Symbol s : new com.sun.tools.javac.model.FilteredMemberList(clazz.members())) {
1701 if (!s.getKind().isField())
1702 continue;
1703
1704 for (Attribute.TypeCompound ta : s.getRawTypeAttributes()) {
1705 if (ta.hasUnknownPosition())
1706 ta.tryFixPosition();
1707
1708 if (ta.position.matchesPos(treePos))
1709 ta.position.updatePosOffset(code.cp);
1710 }
1711 }
1712 }
1713
1714 public void visitNewClass(JCNewClass tree) {
1715 // Enclosing instances or anonymous classes should have been eliminated
1716 // by now.
1717 Assert.check(tree.encl == null && tree.def == null);
1718 setTypeAnnotationPositions(tree.pos);
1719
1720 code.emitop2(new_, makeRef(tree.pos(), tree.type));
1721 code.emitop0(dup);
1722
1723 // Generate code for all arguments, where the expected types are
1724 // the parameters of the constructor's external type (that is,
1725 // any implicit outer instance appears as first parameter).
1726 genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
1727
1728 items.makeMemberItem(tree.constructor, true).invoke();
1729 result = items.makeStackItem(tree.type);
1730 }
1731
1732 public void visitNewArray(JCNewArray tree) {
1733 setTypeAnnotationPositions(tree.pos);
1734
1735 if (tree.elems != null) {
1736 Type elemtype = types.elemtype(tree.type);
1737 loadIntConst(tree.elems.length());
1738 Item arr = makeNewArray(tree.pos(), tree.type, 1);
1739 int i = 0;
1740 for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
1741 arr.duplicate();
1742 loadIntConst(i);
1743 i++;
1744 genExpr(l.head, elemtype).load();
1745 items.makeIndexedItem(elemtype).store();
1746 }
1747 result = arr;
1748 } else {
1749 for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
1750 genExpr(l.head, syms.intType).load();
1751 }
1752 result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
1753 }
1754 }
1755 //where
1756 /** Generate code to create an array with given element type and number
1757 * of dimensions.
1758 */
1759 Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
1760 Type elemtype = types.elemtype(type);
1761 if (types.dimensions(type) > ClassFile.MAX_DIMENSIONS) {
1762 log.error(pos, "limit.dimensions");
1763 nerrs++;
1764 }
1765 int elemcode = Code.arraycode(elemtype);
1766 if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
1767 code.emitAnewarray(makeRef(pos, elemtype), type);
1768 } else if (elemcode == 1) {
1769 code.emitMultianewarray(ndims, makeRef(pos, type), type);
1770 } else {
1771 code.emitNewarray(elemcode, type);
1772 }
1773 return items.makeStackItem(type);
1774 }
1775
1776 public void visitParens(JCParens tree) {
1777 result = genExpr(tree.expr, tree.expr.type);
1778 }
1779
1780 public void visitAssign(JCAssign tree) {
1781 Item l = genExpr(tree.lhs, tree.lhs.type);
1782 genExpr(tree.rhs, tree.lhs.type).load();
1783 if (tree.rhs.type.hasTag(BOT)) {
1784 /* This is just a case of widening reference conversion that per 5.1.5 simply calls
1785 for "regarding a reference as having some other type in a manner that can be proved
1786 correct at compile time."
1787 */
1788 code.state.forceStackTop(tree.lhs.type);
1789 }
1790 result = items.makeAssignItem(l);
1791 }
1792
1793 public void visitAssignop(JCAssignOp tree) {
1794 OperatorSymbol operator = (OperatorSymbol) tree.operator;
1795 Item l;
1796 if (operator.opcode == string_add) {
1797 l = concat.makeConcat(tree);
1798 } else {
1799 // Generate code for first expression
1800 l = genExpr(tree.lhs, tree.lhs.type);
1801
1802 // If we have an increment of -32768 to +32767 of a local
1803 // int variable we can use an incr instruction instead of
1804 // proceeding further.
1805 if ((tree.hasTag(PLUS_ASG) || tree.hasTag(MINUS_ASG)) &&
1806 l instanceof LocalItem &&
1807 tree.lhs.type.getTag().isSubRangeOf(INT) &&
1808 tree.rhs.type.getTag().isSubRangeOf(INT) &&
1809 tree.rhs.type.constValue() != null) {
1810 int ival = ((Number) tree.rhs.type.constValue()).intValue();
1811 if (tree.hasTag(MINUS_ASG)) ival = -ival;
1812 ((LocalItem)l).incr(ival);
1813 result = l;
1814 return;
1815 }
1816 // Otherwise, duplicate expression, load one copy
1817 // and complete binary operation.
1818 l.duplicate();
1819 l.coerce(operator.type.getParameterTypes().head).load();
1820 completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
1821 }
1822 result = items.makeAssignItem(l);
1823 }
1824
1825 public void visitUnary(JCUnary tree) {
1826 OperatorSymbol operator = (OperatorSymbol)tree.operator;
1827 if (tree.hasTag(NOT)) {
1828 CondItem od = genCond(tree.arg, false);
1829 result = od.negate();
1830 } else {
1831 Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
1832 switch (tree.getTag()) {
1833 case POS:
1834 result = od.load();
1835 break;
1836 case NEG:
1837 result = od.load();
1838 code.emitop0(operator.opcode);
1839 break;
1840 case COMPL:
1841 result = od.load();
1842 emitMinusOne(od.typecode);
1843 code.emitop0(operator.opcode);
1844 break;
1845 case PREINC: case PREDEC:
1846 od.duplicate();
1847 if (od instanceof LocalItem &&
1848 (operator.opcode == iadd || operator.opcode == isub)) {
1849 ((LocalItem)od).incr(tree.hasTag(PREINC) ? 1 : -1);
1850 result = od;
1851 } else {
1852 od.load();
1853 code.emitop0(one(od.typecode));
1854 code.emitop0(operator.opcode);
1855 // Perform narrowing primitive conversion if byte,
1856 // char, or short. Fix for 4304655.
1857 if (od.typecode != INTcode &&
1858 Code.truncate(od.typecode) == INTcode)
1859 code.emitop0(int2byte + od.typecode - BYTEcode);
1860 result = items.makeAssignItem(od);
1861 }
1862 break;
1863 case POSTINC: case POSTDEC:
1864 od.duplicate();
1865 if (od instanceof LocalItem &&
1866 (operator.opcode == iadd || operator.opcode == isub)) {
1867 Item res = od.load();
1868 ((LocalItem)od).incr(tree.hasTag(POSTINC) ? 1 : -1);
1869 result = res;
1870 } else {
1871 Item res = od.load();
1872 od.stash(od.typecode);
1873 code.emitop0(one(od.typecode));
1874 code.emitop0(operator.opcode);
1875 // Perform narrowing primitive conversion if byte,
1876 // char, or short. Fix for 4304655.
1877 if (od.typecode != INTcode &&
1878 Code.truncate(od.typecode) == INTcode)
1879 code.emitop0(int2byte + od.typecode - BYTEcode);
1880 od.store();
1881 result = res;
1882 }
1883 break;
1884 case NULLCHK:
1885 result = od.load();
1886 code.emitop0(dup);
1887 genNullCheck(tree.pos());
1888 break;
1889 default:
1890 Assert.error();
1891 }
1892 }
1893 }
1894
1895 /** Generate a null check from the object value at stack top. */
1896 private void genNullCheck(DiagnosticPosition pos) {
1897 if (allowBetterNullChecks) {
1898 callMethod(pos, syms.objectsType, names.requireNonNull,
1899 List.of(syms.objectType), true);
1900 } else {
1901 callMethod(pos, syms.objectType, names.getClass,
1902 List.<Type>nil(), false);
1903 }
1904 code.emitop0(pop);
1905 }
1906
1907 public void visitBinary(JCBinary tree) {
1908 OperatorSymbol operator = (OperatorSymbol)tree.operator;
1909 if (operator.opcode == string_add) {
1910 result = concat.makeConcat(tree);
1911 } else if (tree.hasTag(AND)) {
1912 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
1913 if (!lcond.isFalse()) {
1914 Chain falseJumps = lcond.jumpFalse();
1915 code.resolve(lcond.trueJumps);
1916 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
1917 result = items.
1918 makeCondItem(rcond.opcode,
1919 rcond.trueJumps,
1920 Code.mergeChains(falseJumps,
1921 rcond.falseJumps));
1922 } else {
1923 result = lcond;
1924 }
1925 } else if (tree.hasTag(OR)) {
1926 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
1927 if (!lcond.isTrue()) {
1928 Chain trueJumps = lcond.jumpTrue();
1929 code.resolve(lcond.falseJumps);
1930 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
1931 result = items.
1932 makeCondItem(rcond.opcode,
1933 Code.mergeChains(trueJumps, rcond.trueJumps),
1934 rcond.falseJumps);
1935 } else {
1936 result = lcond;
1937 }
1938 } else {
1939 Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
1940 od.load();
1941 result = completeBinop(tree.lhs, tree.rhs, operator);
1942 }
1943 }
1944
1945
1946 /** Complete generating code for operation, with left operand
1947 * already on stack.
1948 * @param lhs The tree representing the left operand.
1949 * @param rhs The tree representing the right operand.
1950 * @param operator The operator symbol.
1951 */
1952 Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
1953 MethodType optype = (MethodType)operator.type;
1954 int opcode = operator.opcode;
1955 if (opcode >= if_icmpeq && opcode <= if_icmple &&
1956 rhs.type.constValue() instanceof Number &&
1957 ((Number) rhs.type.constValue()).intValue() == 0) {
1958 opcode = opcode + (ifeq - if_icmpeq);
1959 } else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
1960 TreeInfo.isNull(rhs)) {
1961 opcode = opcode + (if_acmp_null - if_acmpeq);
1962 } else {
1963 // The expected type of the right operand is
1964 // the second parameter type of the operator, except for
1965 // shifts with long shiftcount, where we convert the opcode
1966 // to a short shift and the expected type to int.
1967 Type rtype = operator.erasure(types).getParameterTypes().tail.head;
1968 if (opcode >= ishll && opcode <= lushrl) {
1969 opcode = opcode + (ishl - ishll);
1970 rtype = syms.intType;
1971 }
1972 // Generate code for right operand and load.
1973 genExpr(rhs, rtype).load();
1974 // If there are two consecutive opcode instructions,
1975 // emit the first now.
1976 if (opcode >= (1 << preShift)) {
1977 code.emitop0(opcode >> preShift);
1978 opcode = opcode & 0xFF;
1979 }
1980 }
1981 if (opcode >= ifeq && opcode <= if_acmpne ||
1982 opcode == if_acmp_null || opcode == if_acmp_nonnull) {
1983 return items.makeCondItem(opcode);
1984 } else {
1985 code.emitop0(opcode);
1986 return items.makeStackItem(optype.restype);
1987 }
1988 }
1989
1990 public void visitTypeCast(JCTypeCast tree) {
1991 result = genExpr(tree.expr, tree.clazz.type).load();
1992 setTypeAnnotationPositions(tree.pos);
1993 // Additional code is only needed if we cast to a reference type
1994 // which is not statically a supertype of the expression's type.
1995 // For basic types, the coerce(...) in genExpr(...) will do
1996 // the conversion.
1997 if (!tree.clazz.type.isPrimitive() &&
1998 !types.isSameType(tree.expr.type, tree.clazz.type) &&
1999 types.asSuper(tree.expr.type, tree.clazz.type.tsym) == null) {
2000 code.emitop2(checkcast, makeRef(tree.pos(), tree.clazz.type));
2001 }
2002 }
2003
2004 public void visitWildcard(JCWildcard tree) {
2005 throw new AssertionError(this.getClass().getName());
2006 }
2007
2008 public void visitTypeTest(JCInstanceOf tree) {
2009 genExpr(tree.expr, tree.expr.type).load();
2010 setTypeAnnotationPositions(tree.pos);
2011 code.emitop2(instanceof_, makeRef(tree.pos(), tree.clazz.type));
2012 result = items.makeStackItem(syms.booleanType);
2013 }
2014
2015 public void visitIndexed(JCArrayAccess tree) {
2016 genExpr(tree.indexed, tree.indexed.type).load();
2017 genExpr(tree.index, syms.intType).load();
2018 result = items.makeIndexedItem(tree.type);
2019 }
2020
2021 public void visitIdent(JCIdent tree) {
2022 Symbol sym = tree.sym;
2023 if (tree.name == names._this || tree.name == names._super) {
2024 Item res = tree.name == names._this
2025 ? items.makeThisItem()
2026 : items.makeSuperItem();
2027 if (sym.kind == MTH) {
2028 // Generate code to address the constructor.
2029 res.load();
2030 res = items.makeMemberItem(sym, true);
2031 }
2032 result = res;
2033 } else if (sym.kind == VAR && sym.owner.kind == MTH) {
2034 result = items.makeLocalItem((VarSymbol)sym);
2035 } else if (isInvokeDynamic(sym)) {
2036 result = items.makeDynamicItem(sym);
2037 } else if ((sym.flags() & STATIC) != 0) {
2038 if (!isAccessSuper(env.enclMethod))
2039 sym = binaryQualifier(sym, env.enclClass.type);
2040 result = items.makeStaticItem(sym);
2041 } else {
2042 items.makeThisItem().load();
2043 sym = binaryQualifier(sym, env.enclClass.type);
2044 result = items.makeMemberItem(sym, (sym.flags() & PRIVATE) != 0);
2045 }
2046 }
2047
2048 public void visitSelect(JCFieldAccess tree) {
2049 Symbol sym = tree.sym;
2050
2051 if (tree.name == names._class) {
2052 code.emitLdc(makeRef(tree.pos(), tree.selected.type));
2053 result = items.makeStackItem(pt);
2054 return;
2055 }
2056
2057 Symbol ssym = TreeInfo.symbol(tree.selected);
2058
2059 // Are we selecting via super?
2060 boolean selectSuper =
2061 ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2062
2063 // Are we accessing a member of the superclass in an access method
2064 // resulting from a qualified super?
2065 boolean accessSuper = isAccessSuper(env.enclMethod);
2066
2067 Item base = (selectSuper)
2068 ? items.makeSuperItem()
2069 : genExpr(tree.selected, tree.selected.type);
2070
2071 if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2072 // We are seeing a variable that is constant but its selecting
2073 // expression is not.
2074 if ((sym.flags() & STATIC) != 0) {
2075 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2076 base = base.load();
2077 base.drop();
2078 } else {
2079 base.load();
2080 genNullCheck(tree.selected.pos());
2081 }
2082 result = items.
2083 makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
2084 } else {
2085 if (isInvokeDynamic(sym)) {
2086 result = items.makeDynamicItem(sym);
2087 return;
2088 } else {
2089 sym = binaryQualifier(sym, tree.selected.type);
2090 }
2091 if ((sym.flags() & STATIC) != 0) {
2092 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2093 base = base.load();
2094 base.drop();
2095 result = items.makeStaticItem(sym);
2096 } else {
2097 base.load();
2098 if (sym == syms.lengthVar) {
2099 code.emitop0(arraylength);
2100 result = items.makeStackItem(syms.intType);
2101 } else {
2102 result = items.
2103 makeMemberItem(sym,
2104 (sym.flags() & PRIVATE) != 0 ||
2105 selectSuper || accessSuper);
2106 }
2107 }
2108 }
2109 }
2110
2111 public boolean isInvokeDynamic(Symbol sym) {
2112 return sym.kind == MTH && ((MethodSymbol)sym).isDynamic();
2113 }
2114
2115 public void visitLiteral(JCLiteral tree) {
2116 if (tree.type.hasTag(BOT)) {
2117 code.emitop0(aconst_null);
2118 result = items.makeStackItem(tree.type);
2119 }
2120 else
2121 result = items.makeImmediateItem(tree.type, tree.value);
2122 }
2123
2124 public void visitLetExpr(LetExpr tree) {
2125 letExprDepth++;
2126 int limit = code.nextreg;
2127 genStats(tree.defs, env);
2128 result = genExpr(tree.expr, tree.expr.type).load();
2129 code.endScopes(limit);
2130 letExprDepth--;
2131 }
2132
2133 private void generateReferencesToPrunedTree(ClassSymbol classSymbol, Pool pool) {
2134 List<JCTree> prunedInfo = lower.prunedTree.get(classSymbol);
2135 if (prunedInfo != null) {
2136 for (JCTree prunedTree: prunedInfo) {
2137 prunedTree.accept(classReferenceVisitor);
2138 }
2139 }
2140 }
2141
2142 /* ************************************************************************
2143 * main method
2144 *************************************************************************/
2145
2146 /** Generate code for a class definition.
2147 * @param env The attribution environment that belongs to the
2148 * outermost class containing this class definition.
2149 * We need this for resolving some additional symbols.
2150 * @param cdef The tree representing the class definition.
2151 * @return True if code is generated with no errors.
2152 */
2153 public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
2154 try {
2155 attrEnv = env;
2156 ClassSymbol c = cdef.sym;
2157 this.toplevel = env.toplevel;
2158 this.endPosTable = toplevel.endPositions;
2159 c.pool = pool;
2160 pool.reset();
2161 /* method normalizeDefs() can add references to external classes into the constant pool
2162 */
2163 cdef.defs = normalizeDefs(cdef.defs, c);
2164 generateReferencesToPrunedTree(c, pool);
2165 Env<GenContext> localEnv = new Env<>(cdef, new GenContext());
2166 localEnv.toplevel = env.toplevel;
2167 localEnv.enclClass = cdef;
2168
2169 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2170 genDef(l.head, localEnv);
2171 }
2172 if (pool.numEntries() > Pool.MAX_ENTRIES) {
2173 log.error(cdef.pos(), "limit.pool");
2174 nerrs++;
2175 }
2176 if (nerrs != 0) {
2177 // if errors, discard code
2178 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2179 if (l.head.hasTag(METHODDEF))
2180 ((JCMethodDecl) l.head).sym.code = null;
2181 }
2182 }
2183 cdef.defs = List.nil(); // discard trees
2184 return nerrs == 0;
2185 } finally {
2186 // note: this method does NOT support recursion.
2187 attrEnv = null;
2188 this.env = null;
2189 toplevel = null;
2190 endPosTable = null;
2191 nerrs = 0;
2192 }
2193 }
2194
2195 /* ************************************************************************
2196 * Auxiliary classes
2197 *************************************************************************/
2198
2199 /** An abstract class for finalizer generation.
2200 */
2201 abstract class GenFinalizer {
2202 /** Generate code to clean up when unwinding. */
2203 abstract void gen();
2204
2205 /** Generate code to clean up at last. */
2206 abstract void genLast();
2207
2208 /** Does this finalizer have some nontrivial cleanup to perform? */
2209 boolean hasFinalizer() { return true; }
2210 }
2211
2212 /** code generation contexts,
2213 * to be used as type parameter for environments.
2214 */
2215 static class GenContext {
2216
2217 /** A chain for all unresolved jumps that exit the current environment.
2218 */
2219 Chain exit = null;
2220
2221 /** A chain for all unresolved jumps that continue in the
2222 * current environment.
2223 */
2224 Chain cont = null;
2225
2226 /** A closure that generates the finalizer of the current environment.
2227 * Only set for Synchronized and Try contexts.
2228 */
2229 GenFinalizer finalize = null;
2230
2231 /** Is this a switch statement? If so, allocate registers
2232 * even when the variable declaration is unreachable.
2233 */
2234 boolean isSwitch = false;
2235
2236 /** A list buffer containing all gaps in the finalizer range,
2237 * where a catch all exception should not apply.
2238 */
2239 ListBuffer<Integer> gaps = null;
2240
2241 /** Add given chain to exit chain.
2242 */
2243 void addExit(Chain c) {
2244 exit = Code.mergeChains(c, exit);
2245 }
2246
2247 /** Add given chain to cont chain.
2248 */
2249 void addCont(Chain c) {
2250 cont = Code.mergeChains(c, cont);
2251 }
2252 }
2253
2254 }