1 /*
2 * Copyright (c) 1999, 2015, 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.*;
29
30 import com.sun.tools.javac.util.*;
31 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
32 import com.sun.tools.javac.util.List;
33 import com.sun.tools.javac.code.*;
34 import com.sun.tools.javac.code.Attribute.TypeCompound;
35 import com.sun.tools.javac.code.Symbol.VarSymbol;
36 import com.sun.tools.javac.comp.*;
37 import com.sun.tools.javac.tree.*;
38
39 import com.sun.tools.javac.code.Symbol.*;
40 import com.sun.tools.javac.code.Type.*;
41 import com.sun.tools.javac.jvm.Code.*;
42 import com.sun.tools.javac.jvm.Items.*;
43 import com.sun.tools.javac.tree.EndPosTable;
44 import com.sun.tools.javac.tree.JCTree.*;
45
46 import static com.sun.tools.javac.code.Flags.*;
47 import static com.sun.tools.javac.code.Kinds.Kind.*;
48 import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
49 import static com.sun.tools.javac.code.TypeTag.*;
50 import static com.sun.tools.javac.jvm.ByteCodes.*;
51 import static com.sun.tools.javac.jvm.CRTFlags.*;
52 import static com.sun.tools.javac.main.Option.*;
53 import static com.sun.tools.javac.tree.JCTree.Tag.*;
54
55 /** This pass maps flat Java (i.e. without inner classes) to bytecodes.
56 *
57 * <p><b>This is NOT part of any supported API.
58 * If you write code that depends on this, you do so at your own risk.
59 * This code and its internal interfaces are subject to change or
60 * deletion without notice.</b>
61 */
62 public class Gen extends JCTree.Visitor {
63 protected static final Context.Key<Gen> genKey = new Context.Key<>();
64
65 private final Log log;
66 private final Symtab syms;
67 private final Check chk;
68 private final Resolve rs;
69 private final TreeMaker make;
70 private final Names names;
71 private final Target target;
72 private final Map<Type,Symbol> stringBufferAppend;
73 private Name accessDollar;
74 private final Types types;
75 private final Lower lower;
76 private final Flow flow;
77 private final Annotate annotate;
78
79 /** Format of stackmap tables to be generated. */
80 private final Code.StackMapFormat stackMap;
81
82 /** A type that serves as the expected type for all method expressions.
83 */
84 private final Type methodType;
85
86 public static Gen instance(Context context) {
87 Gen instance = context.get(genKey);
88 if (instance == null)
89 instance = new Gen(context);
90 return instance;
91 }
92
93 /** Constant pool, reset by genClass.
94 */
95 private Pool pool;
96
97 protected Gen(Context context) {
98 context.put(genKey, this);
99
100 names = Names.instance(context);
101 log = Log.instance(context);
102 syms = Symtab.instance(context);
103 chk = Check.instance(context);
104 rs = Resolve.instance(context);
105 make = TreeMaker.instance(context);
106 target = Target.instance(context);
107 types = Types.instance(context);
108 methodType = new MethodType(null, null, null, syms.methodClass);
109 stringBufferAppend = new HashMap<>();
110 accessDollar = names.
111 fromString("access" + target.syntheticNameChar());
112 flow = Flow.instance(context);
113 lower = Lower.instance(context);
114
115 Options options = Options.instance(context);
116 lineDebugInfo =
117 options.isUnset(G_CUSTOM) ||
118 options.isSet(G_CUSTOM, "lines");
119 varDebugInfo =
120 options.isUnset(G_CUSTOM)
121 ? options.isSet(G)
122 : options.isSet(G_CUSTOM, "vars");
123 genCrt = options.isSet(XJCOV);
124 debugCode = options.isSet("debugcode");
125 allowInvokedynamic = target.hasInvokedynamic() || options.isSet("invokedynamic");
126 allowBetterNullChecks = target.hasObjects();
127 pool = new Pool(types);
128
129 // ignore cldc because we cannot have both stackmap formats
130 this.stackMap = StackMapFormat.JSR202;
131
132 // by default, avoid jsr's for simple finalizers
133 int setjsrlimit = 50;
134 String jsrlimitString = options.get("jsrlimit");
135 if (jsrlimitString != null) {
136 try {
137 setjsrlimit = Integer.parseInt(jsrlimitString);
138 } catch (NumberFormatException ex) {
139 // ignore ill-formed numbers for jsrlimit
140 }
141 }
142 this.jsrlimit = setjsrlimit;
143 this.useJsrLocally = false; // reset in visitTry
144 annotate = Annotate.instance(context);
145 }
146
147 /** Switches
148 */
149 private final boolean lineDebugInfo;
150 private final boolean varDebugInfo;
151 private final boolean genCrt;
152 private final boolean debugCode;
153 private final boolean allowInvokedynamic;
154 private final boolean allowBetterNullChecks;
155
156 /** Default limit of (approximate) size of finalizer to inline.
157 * Zero means always use jsr. 100 or greater means never use
158 * jsr.
159 */
160 private final int jsrlimit;
161
162 /** True if jsr is used.
163 */
164 private boolean useJsrLocally;
165
166 /** Code buffer, set by genMethod.
167 */
168 private Code code;
169
170 /** Items structure, set by genMethod.
171 */
172 private Items items;
173
174 /** Environment for symbol lookup, set by genClass
175 */
176 private Env<AttrContext> attrEnv;
177
178 /** The top level tree.
179 */
180 private JCCompilationUnit toplevel;
181
182 /** The number of code-gen errors in this class.
183 */
184 private int nerrs = 0;
185
186 /** An object containing mappings of syntax trees to their
187 * ending source positions.
188 */
189 EndPosTable endPosTable;
190
191 /** Generate code to load an integer constant.
192 * @param n The integer to be loaded.
193 */
194 void loadIntConst(int n) {
195 items.makeImmediateItem(syms.intType, n).load();
196 }
197
198 /** The opcode that loads a zero constant of a given type code.
199 * @param tc The given type code (@see ByteCode).
200 */
201 public static int zero(int tc) {
202 switch(tc) {
203 case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
204 return iconst_0;
205 case LONGcode:
206 return lconst_0;
207 case FLOATcode:
208 return fconst_0;
209 case DOUBLEcode:
210 return dconst_0;
211 default:
212 throw new AssertionError("zero");
213 }
214 }
215
216 /** The opcode that loads a one constant of a given type code.
217 * @param tc The given type code (@see ByteCode).
218 */
219 public static int one(int tc) {
220 return zero(tc) + 1;
221 }
222
223 /** Generate code to load -1 of the given type code (either int or long).
224 * @param tc The given type code (@see ByteCode).
225 */
226 void emitMinusOne(int tc) {
227 if (tc == LONGcode) {
228 items.makeImmediateItem(syms.longType, new Long(-1)).load();
229 } else {
230 code.emitop0(iconst_m1);
231 }
232 }
233
234 /** Construct a symbol to reflect the qualifying type that should
235 * appear in the byte code as per JLS 13.1.
236 *
237 * For {@literal target >= 1.2}: Clone a method with the qualifier as owner (except
238 * for those cases where we need to work around VM bugs).
239 *
240 * For {@literal target <= 1.1}: If qualified variable or method is defined in a
241 * non-accessible class, clone it with the qualifier class as owner.
242 *
243 * @param sym The accessed symbol
244 * @param site The qualifier's type.
245 */
246 Symbol binaryQualifier(Symbol sym, Type site) {
247
248 if (site.hasTag(ARRAY)) {
249 if (sym == syms.lengthVar ||
250 sym.owner != syms.arrayClass)
251 return sym;
252 // array clone can be qualified by the array type in later targets
253 Symbol qualifier = new ClassSymbol(Flags.PUBLIC, site.tsym.name,
254 site, syms.noSymbol);
255 return sym.clone(qualifier);
256 }
257
258 if (sym.owner == site.tsym ||
259 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
260 return sym;
261 }
262
263 // leave alone methods inherited from Object
264 // JLS 13.1.
265 if (sym.owner == syms.objectType.tsym)
266 return sym;
267
268 return sym.clone(site.tsym);
269 }
270
271 /** Insert a reference to given type in the constant pool,
272 * checking for an array with too many dimensions;
273 * return the reference's index.
274 * @param type The type for which a reference is inserted.
275 */
276 int makeRef(DiagnosticPosition pos, Type type) {
277 checkDimension(pos, type);
278 if (type.isAnnotated()) {
279 return pool.put((Object)type);
280 } else {
281 return pool.put(type.hasTag(CLASS) ? (Object)type.tsym : (Object)type);
282 }
283 }
284
285 /** Check if the given type is an array with too many dimensions.
286 */
287 private void checkDimension(DiagnosticPosition pos, Type t) {
288 switch (t.getTag()) {
289 case METHOD:
290 checkDimension(pos, t.getReturnType());
291 for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
292 checkDimension(pos, args.head);
293 break;
294 case ARRAY:
295 if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
296 log.error(pos, "limit.dimensions");
297 nerrs++;
298 }
299 break;
300 default:
301 break;
302 }
303 }
304
305 /** Create a tempory variable.
306 * @param type The variable's type.
307 */
308 LocalItem makeTemp(Type type) {
309 VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
310 names.empty,
311 type,
312 env.enclMethod.sym);
313 code.newLocal(v);
314 return items.makeLocalItem(v);
315 }
316
317 /** Generate code to call a non-private method or constructor.
318 * @param pos Position to be used for error reporting.
319 * @param site The type of which the method is a member.
320 * @param name The method's name.
321 * @param argtypes The method's argument types.
322 * @param isStatic A flag that indicates whether we call a
323 * static or instance method.
324 */
325 void callMethod(DiagnosticPosition pos,
326 Type site, Name name, List<Type> argtypes,
327 boolean isStatic) {
328 Symbol msym = rs.
329 resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
330 if (isStatic) items.makeStaticItem(msym).invoke();
331 else items.makeMemberItem(msym, name == names.init).invoke();
332 }
333
334 /** Is the given method definition an access method
335 * resulting from a qualified super? This is signified by an odd
336 * access code.
337 */
338 private boolean isAccessSuper(JCMethodDecl enclMethod) {
339 return
340 (enclMethod.mods.flags & SYNTHETIC) != 0 &&
341 isOddAccessName(enclMethod.name);
342 }
343
344 /** Does given name start with "access$" and end in an odd digit?
345 */
346 private boolean isOddAccessName(Name name) {
347 return
348 name.startsWith(accessDollar) &&
349 (name.getByteAt(name.getByteLength() - 1) & 1) == 1;
350 }
351
352 /* ************************************************************************
353 * Non-local exits
354 *************************************************************************/
355
356 /** Generate code to invoke the finalizer associated with given
357 * environment.
358 * Any calls to finalizers are appended to the environments `cont' chain.
359 * Mark beginning of gap in catch all range for finalizer.
360 */
361 void genFinalizer(Env<GenContext> env) {
362 if (code.isAlive() && env.info.finalize != null)
363 env.info.finalize.gen();
364 }
365
366 /** Generate code to call all finalizers of structures aborted by
367 * a non-local
368 * exit. Return target environment of the non-local exit.
369 * @param target The tree representing the structure that's aborted
370 * @param env The environment current at the non-local exit.
371 */
372 Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
373 Env<GenContext> env1 = env;
374 while (true) {
375 genFinalizer(env1);
376 if (env1.tree == target) break;
377 env1 = env1.next;
378 }
379 return env1;
380 }
381
382 /** Mark end of gap in catch-all range for finalizer.
383 * @param env the environment which might contain the finalizer
384 * (if it does, env.info.gaps != null).
385 */
386 void endFinalizerGap(Env<GenContext> env) {
387 if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
388 env.info.gaps.append(code.curCP());
389 }
390
391 /** Mark end of all gaps in catch-all ranges for finalizers of environments
392 * lying between, and including to two environments.
393 * @param from the most deeply nested environment to mark
394 * @param to the least deeply nested environment to mark
395 */
396 void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
397 Env<GenContext> last = null;
398 while (last != to) {
399 endFinalizerGap(from);
400 last = from;
401 from = from.next;
402 }
403 }
404
405 /** Do any of the structures aborted by a non-local exit have
406 * finalizers that require an empty stack?
407 * @param target The tree representing the structure that's aborted
408 * @param env The environment current at the non-local exit.
409 */
410 boolean hasFinally(JCTree target, Env<GenContext> env) {
411 while (env.tree != target) {
412 if (env.tree.hasTag(TRY) && env.info.finalize.hasFinalizer())
413 return true;
414 env = env.next;
415 }
416 return false;
417 }
418
419 /* ************************************************************************
420 * Normalizing class-members.
421 *************************************************************************/
422
423 /** Distribute member initializer code into constructors and {@code <clinit>}
424 * method.
425 * @param defs The list of class member declarations.
426 * @param c The enclosing class.
427 */
428 List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
429 ListBuffer<JCStatement> initCode = new ListBuffer<>();
430 ListBuffer<Attribute.TypeCompound> initTAs = new ListBuffer<>();
431 ListBuffer<JCStatement> clinitCode = new ListBuffer<>();
432 ListBuffer<Attribute.TypeCompound> clinitTAs = new ListBuffer<>();
433 ListBuffer<JCTree> methodDefs = new ListBuffer<>();
434 // Sort definitions into three listbuffers:
435 // - initCode for instance initializers
436 // - clinitCode for class initializers
437 // - methodDefs for method definitions
438 for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
439 JCTree def = l.head;
440 switch (def.getTag()) {
441 case BLOCK:
442 JCBlock block = (JCBlock)def;
443 if ((block.flags & STATIC) != 0)
444 clinitCode.append(block);
445 else if ((block.flags & SYNTHETIC) == 0)
446 initCode.append(block);
447 break;
448 case METHODDEF:
449 methodDefs.append(def);
450 break;
451 case VARDEF:
452 JCVariableDecl vdef = (JCVariableDecl) def;
453 VarSymbol sym = vdef.sym;
454 checkDimension(vdef.pos(), sym.type);
455 if (vdef.init != null) {
456 if ((sym.flags() & STATIC) == 0) {
457 // Always initialize instance variables.
458 JCStatement init = make.at(vdef.pos()).
459 Assignment(sym, vdef.init);
460 initCode.append(init);
461 endPosTable.replaceTree(vdef, init);
462 initTAs.addAll(getAndRemoveNonFieldTAs(sym));
463 } else if (sym.getConstValue() == null) {
464 // Initialize class (static) variables only if
465 // they are not compile-time constants.
466 JCStatement init = make.at(vdef.pos).
467 Assignment(sym, vdef.init);
468 clinitCode.append(init);
469 endPosTable.replaceTree(vdef, init);
470 clinitTAs.addAll(getAndRemoveNonFieldTAs(sym));
471 } else {
472 checkStringConstant(vdef.init.pos(), sym.getConstValue());
473 /* if the init contains a reference to an external class, add it to the
474 * constant's pool
475 */
476 vdef.init.accept(classReferenceVisitor);
477 }
478 }
479 break;
480 default:
481 Assert.error();
482 }
483 }
484 // Insert any instance initializers into all constructors.
485 if (initCode.length() != 0) {
486 List<JCStatement> inits = initCode.toList();
487 initTAs.addAll(c.getInitTypeAttributes());
488 List<Attribute.TypeCompound> initTAlist = initTAs.toList();
489 for (JCTree t : methodDefs) {
490 normalizeMethod((JCMethodDecl)t, inits, initTAlist);
491 }
492 }
493 // If there are class initializers, create a <clinit> method
494 // that contains them as its body.
495 if (clinitCode.length() != 0) {
496 MethodSymbol clinit = new MethodSymbol(
497 STATIC | (c.flags() & STRICTFP),
498 names.clinit,
499 new MethodType(
500 List.<Type>nil(), syms.voidType,
501 List.<Type>nil(), syms.methodClass),
502 c);
503 c.members().enter(clinit);
504 List<JCStatement> clinitStats = clinitCode.toList();
505 JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
506 block.endpos = TreeInfo.endPos(clinitStats.last());
507 methodDefs.append(make.MethodDef(clinit, block));
508
509 if (!clinitTAs.isEmpty())
510 clinit.appendUniqueTypeAttributes(clinitTAs.toList());
511 if (!c.getClassInitTypeAttributes().isEmpty())
512 clinit.appendUniqueTypeAttributes(c.getClassInitTypeAttributes());
513 }
514 // Return all method definitions.
515 return methodDefs.toList();
516 }
517
518 private List<Attribute.TypeCompound> getAndRemoveNonFieldTAs(VarSymbol sym) {
519 List<TypeCompound> tas = sym.getRawTypeAttributes();
520 ListBuffer<Attribute.TypeCompound> fieldTAs = new ListBuffer<>();
521 ListBuffer<Attribute.TypeCompound> nonfieldTAs = new ListBuffer<>();
522 for (TypeCompound ta : tas) {
523 Assert.check(ta.getPosition().type != TargetType.UNKNOWN);
524 if (ta.getPosition().type == TargetType.FIELD) {
525 fieldTAs.add(ta);
526 } else {
527 nonfieldTAs.add(ta);
528 }
529 }
530 sym.setTypeAttributes(fieldTAs.toList());
531 return nonfieldTAs.toList();
532 }
533
534 /** Check a constant value and report if it is a string that is
535 * too large.
536 */
537 private void checkStringConstant(DiagnosticPosition pos, Object constValue) {
538 if (nerrs != 0 || // only complain about a long string once
539 constValue == null ||
540 !(constValue instanceof String) ||
541 ((String)constValue).length() < Pool.MAX_STRING_LENGTH)
542 return;
543 log.error(pos, "limit.string");
544 nerrs++;
545 }
546
547 /** Insert instance initializer code into initial constructor.
548 * @param md The tree potentially representing a
549 * constructor's definition.
550 * @param initCode The list of instance initializer statements.
551 * @param initTAs Type annotations from the initializer expression.
552 */
553 void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode, List<TypeCompound> initTAs) {
554 if (md.name == names.init && TreeInfo.isInitialConstructor(md)) {
555 // We are seeing a constructor that does not call another
556 // constructor of the same class.
557 List<JCStatement> stats = md.body.stats;
558 ListBuffer<JCStatement> newstats = new ListBuffer<>();
559
560 if (stats.nonEmpty()) {
561 // Copy initializers of synthetic variables generated in
562 // the translation of inner classes.
563 while (TreeInfo.isSyntheticInit(stats.head)) {
564 newstats.append(stats.head);
565 stats = stats.tail;
566 }
567 // Copy superclass constructor call
568 newstats.append(stats.head);
569 stats = stats.tail;
570 // Copy remaining synthetic initializers.
571 while (stats.nonEmpty() &&
572 TreeInfo.isSyntheticInit(stats.head)) {
573 newstats.append(stats.head);
574 stats = stats.tail;
575 }
576 // Now insert the initializer code.
577 newstats.appendList(initCode);
578 // And copy all remaining statements.
579 while (stats.nonEmpty()) {
580 newstats.append(stats.head);
581 stats = stats.tail;
582 }
583 }
584 md.body.stats = newstats.toList();
585 if (md.body.endpos == Position.NOPOS)
586 md.body.endpos = TreeInfo.endPos(md.body.stats.last());
587
588 md.sym.appendUniqueTypeAttributes(initTAs);
589 }
590 }
591
592 /* ************************************************************************
593 * Traversal methods
594 *************************************************************************/
595
596 /** Visitor argument: The current environment.
597 */
598 Env<GenContext> env;
599
600 /** Visitor argument: The expected type (prototype).
601 */
602 Type pt;
603
604 /** Visitor result: The item representing the computed value.
605 */
606 Item result;
607
608 /** Visitor method: generate code for a definition, catching and reporting
609 * any completion failures.
610 * @param tree The definition to be visited.
611 * @param env The environment current at the definition.
612 */
613 public void genDef(JCTree tree, Env<GenContext> env) {
614 Env<GenContext> prevEnv = this.env;
615 try {
616 this.env = env;
617 tree.accept(this);
618 } catch (CompletionFailure ex) {
619 chk.completionError(tree.pos(), ex);
620 } finally {
621 this.env = prevEnv;
622 }
623 }
624
625 /** Derived visitor method: check whether CharacterRangeTable
626 * should be emitted, if so, put a new entry into CRTable
627 * and call method to generate bytecode.
628 * If not, just call method to generate bytecode.
629 * @see #genStat(JCTree, Env)
630 *
631 * @param tree The tree to be visited.
632 * @param env The environment to use.
633 * @param crtFlags The CharacterRangeTable flags
634 * indicating type of the entry.
635 */
636 public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
637 if (!genCrt) {
638 genStat(tree, env);
639 return;
640 }
641 int startpc = code.curCP();
642 genStat(tree, env);
643 if (tree.hasTag(Tag.BLOCK)) crtFlags |= CRT_BLOCK;
644 code.crt.put(tree, crtFlags, startpc, code.curCP());
645 }
646
647 /** Derived visitor method: generate code for a statement.
648 */
649 public void genStat(JCTree tree, Env<GenContext> env) {
650 if (code.isAlive()) {
651 code.statBegin(tree.pos);
652 genDef(tree, env);
653 } else if (env.info.isSwitch && tree.hasTag(VARDEF)) {
654 // variables whose declarations are in a switch
655 // can be used even if the decl is unreachable.
656 code.newLocal(((JCVariableDecl) tree).sym);
657 }
658 }
659
660 /** Derived visitor method: check whether CharacterRangeTable
661 * should be emitted, if so, put a new entry into CRTable
662 * and call method to generate bytecode.
663 * If not, just call method to generate bytecode.
664 * @see #genStats(List, Env)
665 *
666 * @param trees The list of trees to be visited.
667 * @param env The environment to use.
668 * @param crtFlags The CharacterRangeTable flags
669 * indicating type of the entry.
670 */
671 public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
672 if (!genCrt) {
673 genStats(trees, env);
674 return;
675 }
676 if (trees.length() == 1) { // mark one statement with the flags
677 genStat(trees.head, env, crtFlags | CRT_STATEMENT);
678 } else {
679 int startpc = code.curCP();
680 genStats(trees, env);
681 code.crt.put(trees, crtFlags, startpc, code.curCP());
682 }
683 }
684
685 /** Derived visitor method: generate code for a list of statements.
686 */
687 public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
688 for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
689 genStat(l.head, env, CRT_STATEMENT);
690 }
691
692 /** Derived visitor method: check whether CharacterRangeTable
693 * should be emitted, if so, put a new entry into CRTable
694 * and call method to generate bytecode.
695 * If not, just call method to generate bytecode.
696 * @see #genCond(JCTree,boolean)
697 *
698 * @param tree The tree to be visited.
699 * @param crtFlags The CharacterRangeTable flags
700 * indicating type of the entry.
701 */
702 public CondItem genCond(JCTree tree, int crtFlags) {
703 if (!genCrt) return genCond(tree, false);
704 int startpc = code.curCP();
705 CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
706 code.crt.put(tree, crtFlags, startpc, code.curCP());
707 return item;
708 }
709
710 /** Derived visitor method: generate code for a boolean
711 * expression in a control-flow context.
712 * @param _tree The expression to be visited.
713 * @param markBranches The flag to indicate that the condition is
714 * a flow controller so produced conditions
715 * should contain a proper tree to generate
716 * CharacterRangeTable branches for them.
717 */
718 public CondItem genCond(JCTree _tree, boolean markBranches) {
719 JCTree inner_tree = TreeInfo.skipParens(_tree);
720 if (inner_tree.hasTag(CONDEXPR)) {
721 JCConditional tree = (JCConditional)inner_tree;
722 CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
723 if (cond.isTrue()) {
724 code.resolve(cond.trueJumps);
725 CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
726 if (markBranches) result.tree = tree.truepart;
727 return result;
728 }
729 if (cond.isFalse()) {
730 code.resolve(cond.falseJumps);
731 CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
732 if (markBranches) result.tree = tree.falsepart;
733 return result;
734 }
735 Chain secondJumps = cond.jumpFalse();
736 code.resolve(cond.trueJumps);
737 CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
738 if (markBranches) first.tree = tree.truepart;
739 Chain falseJumps = first.jumpFalse();
740 code.resolve(first.trueJumps);
741 Chain trueJumps = code.branch(goto_);
742 code.resolve(secondJumps);
743 CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
744 CondItem result = items.makeCondItem(second.opcode,
745 Code.mergeChains(trueJumps, second.trueJumps),
746 Code.mergeChains(falseJumps, second.falseJumps));
747 if (markBranches) result.tree = tree.falsepart;
748 return result;
749 } else {
750 CondItem result = genExpr(_tree, syms.booleanType).mkCond();
751 if (markBranches) result.tree = _tree;
752 return result;
753 }
754 }
755
756 /** Visitor class for expressions which might be constant expressions.
757 * This class is a subset of TreeScanner. Intended to visit trees pruned by
758 * Lower as long as constant expressions looking for references to any
759 * ClassSymbol. Any such reference will be added to the constant pool so
760 * automated tools can detect class dependencies better.
761 */
762 class ClassReferenceVisitor extends JCTree.Visitor {
763
764 @Override
765 public void visitTree(JCTree tree) {}
766
767 @Override
768 public void visitBinary(JCBinary tree) {
769 tree.lhs.accept(this);
770 tree.rhs.accept(this);
771 }
772
773 @Override
774 public void visitSelect(JCFieldAccess tree) {
775 if (tree.selected.type.hasTag(CLASS)) {
776 makeRef(tree.selected.pos(), tree.selected.type);
777 }
778 }
779
780 @Override
781 public void visitIdent(JCIdent tree) {
782 if (tree.sym.owner instanceof ClassSymbol) {
783 pool.put(tree.sym.owner);
784 }
785 }
786
787 @Override
788 public void visitConditional(JCConditional tree) {
789 tree.cond.accept(this);
790 tree.truepart.accept(this);
791 tree.falsepart.accept(this);
792 }
793
794 @Override
795 public void visitUnary(JCUnary tree) {
796 tree.arg.accept(this);
797 }
798
799 @Override
800 public void visitParens(JCParens tree) {
801 tree.expr.accept(this);
802 }
803
804 @Override
805 public void visitTypeCast(JCTypeCast tree) {
806 tree.expr.accept(this);
807 }
808 }
809
810 private ClassReferenceVisitor classReferenceVisitor = new ClassReferenceVisitor();
811
812 /** Visitor method: generate code for an expression, catching and reporting
813 * any completion failures.
814 * @param tree The expression to be visited.
815 * @param pt The expression's expected type (proto-type).
816 */
817 public Item genExpr(JCTree tree, Type pt) {
818 Type prevPt = this.pt;
819 try {
820 if (tree.type.constValue() != null) {
821 // Short circuit any expressions which are constants
822 tree.accept(classReferenceVisitor);
823 checkStringConstant(tree.pos(), tree.type.constValue());
824 result = items.makeImmediateItem(tree.type, tree.type.constValue());
825 } else {
826 this.pt = pt;
827 tree.accept(this);
828 }
829 return result.coerce(pt);
830 } catch (CompletionFailure ex) {
831 chk.completionError(tree.pos(), ex);
832 code.state.stacksize = 1;
833 return items.makeStackItem(pt);
834 } finally {
835 this.pt = prevPt;
836 }
837 }
838
839 /** Derived visitor method: generate code for a list of method arguments.
840 * @param trees The argument expressions to be visited.
841 * @param pts The expression's expected types (i.e. the formal parameter
842 * types of the invoked method).
843 */
844 public void genArgs(List<JCExpression> trees, List<Type> pts) {
845 for (List<JCExpression> l = trees; l.nonEmpty(); l = l.tail) {
846 genExpr(l.head, pts.head).load();
847 pts = pts.tail;
848 }
849 // require lists be of same length
850 Assert.check(pts.isEmpty());
851 }
852
853 /* ************************************************************************
854 * Visitor methods for statements and definitions
855 *************************************************************************/
856
857 /** Thrown when the byte code size exceeds limit.
858 */
859 public static class CodeSizeOverflow extends RuntimeException {
860 private static final long serialVersionUID = 0;
861 public CodeSizeOverflow() {}
862 }
863
864 public void visitMethodDef(JCMethodDecl tree) {
865 // Create a new local environment that points pack at method
866 // definition.
867 Env<GenContext> localEnv = env.dup(tree);
868 localEnv.enclMethod = tree;
869 // The expected type of every return statement in this method
870 // is the method's return type.
871 this.pt = tree.sym.erasure(types).getReturnType();
872
873 checkDimension(tree.pos(), tree.sym.erasure(types));
874 genMethod(tree, localEnv, false);
875 }
876 //where
877 /** Generate code for a method.
878 * @param tree The tree representing the method definition.
879 * @param env The environment current for the method body.
880 * @param fatcode A flag that indicates whether all jumps are
881 * within 32K. We first invoke this method under
882 * the assumption that fatcode == false, i.e. all
883 * jumps are within 32K. If this fails, fatcode
884 * is set to true and we try again.
885 */
886 void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
887 MethodSymbol meth = tree.sym;
888 int extras = 0;
889 // Count up extra parameters
890 if (meth.isConstructor()) {
891 extras++;
892 if (meth.enclClass().isInner() &&
893 !meth.enclClass().isStatic()) {
894 extras++;
895 }
896 } else if ((tree.mods.flags & STATIC) == 0) {
897 extras++;
898 }
899 // System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
900 if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) + extras >
901 ClassFile.MAX_PARAMETERS) {
902 log.error(tree.pos(), "limit.parameters");
903 nerrs++;
904 }
905
906 else if (tree.body != null) {
907 // Create a new code structure and initialize it.
908 int startpcCrt = initCode(tree, env, fatcode);
909
910 try {
911 genStat(tree.body, env);
912 } catch (CodeSizeOverflow e) {
913 // Failed due to code limit, try again with jsr/ret
914 startpcCrt = initCode(tree, env, fatcode);
915 genStat(tree.body, env);
916 }
917
918 if (code.state.stacksize != 0) {
919 log.error(tree.body.pos(), "stack.sim.error", tree);
920 throw new AssertionError();
921 }
922
923 // If last statement could complete normally, insert a
924 // return at the end.
925 if (code.isAlive()) {
926 code.statBegin(TreeInfo.endPos(tree.body));
927 if (env.enclMethod == null ||
928 env.enclMethod.sym.type.getReturnType().hasTag(VOID)) {
929 code.emitop0(return_);
930 } else {
931 // sometime dead code seems alive (4415991);
932 // generate a small loop instead
933 int startpc = code.entryPoint();
934 CondItem c = items.makeCondItem(goto_);
935 code.resolve(c.jumpTrue(), startpc);
936 }
937 }
938 if (genCrt)
939 code.crt.put(tree.body,
940 CRT_BLOCK,
941 startpcCrt,
942 code.curCP());
943
944 code.endScopes(0);
945
946 // If we exceeded limits, panic
947 if (code.checkLimits(tree.pos(), log)) {
948 nerrs++;
949 return;
950 }
951
952 // If we generated short code but got a long jump, do it again
953 // with fatCode = true.
954 if (!fatcode && code.fatcode) genMethod(tree, env, true);
955
956 // Clean up
957 if(stackMap == StackMapFormat.JSR202) {
958 code.lastFrame = null;
959 code.frameBeforeLast = null;
960 }
961
962 // Compress exception table
963 code.compressCatchTable();
964
965 // Fill in type annotation positions for exception parameters
966 code.fillExceptionParameterPositions();
967 }
968 }
969
970 private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
971 MethodSymbol meth = tree.sym;
972
973 // Create a new code structure.
974 meth.code = code = new Code(meth,
975 fatcode,
976 lineDebugInfo ? toplevel.lineMap : null,
977 varDebugInfo,
978 stackMap,
979 debugCode,
980 genCrt ? new CRTable(tree, env.toplevel.endPositions)
981 : null,
982 syms,
983 types,
984 pool);
985 items = new Items(pool, code, syms, types);
986 if (code.debugCode) {
987 System.err.println(meth + " for body " + tree);
988 }
989
990 // If method is not static, create a new local variable address
991 // for `this'.
992 if ((tree.mods.flags & STATIC) == 0) {
993 Type selfType = meth.owner.type;
994 if (meth.isConstructor() && selfType != syms.objectType)
995 selfType = UninitializedType.uninitializedThis(selfType);
996 code.setDefined(
997 code.newLocal(
998 new VarSymbol(FINAL, names._this, selfType, meth.owner)));
999 }
1000
1001 // Mark all parameters as defined from the beginning of
1002 // the method.
1003 for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1004 checkDimension(l.head.pos(), l.head.sym.type);
1005 code.setDefined(code.newLocal(l.head.sym));
1006 }
1007
1008 // Get ready to generate code for method body.
1009 int startpcCrt = genCrt ? code.curCP() : 0;
1010 code.entryPoint();
1011
1012 // Suppress initial stackmap
1013 code.pendingStackMap = false;
1014
1015 return startpcCrt;
1016 }
1017
1018 public void visitVarDef(JCVariableDecl tree) {
1019 VarSymbol v = tree.sym;
1020 code.newLocal(v);
1021 if (tree.init != null) {
1022 checkStringConstant(tree.init.pos(), v.getConstValue());
1023 if (v.getConstValue() == null || varDebugInfo) {
1024 genExpr(tree.init, v.erasure(types)).load();
1025 items.makeLocalItem(v).store();
1026 }
1027 }
1028 checkDimension(tree.pos(), v.type);
1029 }
1030
1031 public void visitSkip(JCSkip tree) {
1032 }
1033
1034 public void visitBlock(JCBlock tree) {
1035 int limit = code.nextreg;
1036 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1037 genStats(tree.stats, localEnv);
1038 // End the scope of all block-local variables in variable info.
1039 if (!env.tree.hasTag(METHODDEF)) {
1040 code.statBegin(tree.endpos);
1041 code.endScopes(limit);
1042 code.pendingStatPos = Position.NOPOS;
1043 }
1044 }
1045
1046 public void visitDoLoop(JCDoWhileLoop tree) {
1047 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), false);
1048 }
1049
1050 public void visitWhileLoop(JCWhileLoop tree) {
1051 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), true);
1052 }
1053
1054 public void visitForLoop(JCForLoop tree) {
1055 int limit = code.nextreg;
1056 genStats(tree.init, env);
1057 genLoop(tree, tree.body, tree.cond, tree.step, true);
1058 code.endScopes(limit);
1059 }
1060 //where
1061 /** Generate code for a loop.
1062 * @param loop The tree representing the loop.
1063 * @param body The loop's body.
1064 * @param cond The loop's controling condition.
1065 * @param step "Step" statements to be inserted at end of
1066 * each iteration.
1067 * @param testFirst True if the loop test belongs before the body.
1068 */
1069 private void genLoop(JCStatement loop,
1070 JCStatement body,
1071 JCExpression cond,
1072 List<JCExpressionStatement> step,
1073 boolean testFirst) {
1074 Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1075 int startpc = code.entryPoint();
1076 if (testFirst) { //while or for loop
1077 CondItem c;
1078 if (cond != null) {
1079 code.statBegin(cond.pos);
1080 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1081 } else {
1082 c = items.makeCondItem(goto_);
1083 }
1084 Chain loopDone = c.jumpFalse();
1085 code.resolve(c.trueJumps);
1086 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1087 code.resolve(loopEnv.info.cont);
1088 genStats(step, loopEnv);
1089 code.resolve(code.branch(goto_), startpc);
1090 code.resolve(loopDone);
1091 } else {
1092 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1093 code.resolve(loopEnv.info.cont);
1094 genStats(step, loopEnv);
1095 CondItem c;
1096 if (cond != null) {
1097 code.statBegin(cond.pos);
1098 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1099 } else {
1100 c = items.makeCondItem(goto_);
1101 }
1102 code.resolve(c.jumpTrue(), startpc);
1103 code.resolve(c.falseJumps);
1104 }
1105 Chain exit = loopEnv.info.exit;
1106 if (exit != null) {
1107 code.resolve(exit);
1108 exit.state.defined.excludeFrom(code.nextreg);
1109 }
1110 }
1111
1112 public void visitForeachLoop(JCEnhancedForLoop tree) {
1113 throw new AssertionError(); // should have been removed by Lower.
1114 }
1115
1116 public void visitLabelled(JCLabeledStatement tree) {
1117 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1118 genStat(tree.body, localEnv, CRT_STATEMENT);
1119 Chain exit = localEnv.info.exit;
1120 if (exit != null) {
1121 code.resolve(exit);
1122 exit.state.defined.excludeFrom(code.nextreg);
1123 }
1124 }
1125
1126 public void visitSwitch(JCSwitch tree) {
1127 int limit = code.nextreg;
1128 Assert.check(!tree.selector.type.hasTag(CLASS));
1129 int startpcCrt = genCrt ? code.curCP() : 0;
1130 Item sel = genExpr(tree.selector, syms.intType);
1131 List<JCCase> cases = tree.cases;
1132 if (cases.isEmpty()) {
1133 // We are seeing: switch <sel> {}
1134 sel.load().drop();
1135 if (genCrt)
1136 code.crt.put(TreeInfo.skipParens(tree.selector),
1137 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1138 } else {
1139 // We are seeing a nonempty switch.
1140 sel.load();
1141 if (genCrt)
1142 code.crt.put(TreeInfo.skipParens(tree.selector),
1143 CRT_FLOW_CONTROLLER, startpcCrt, code.curCP());
1144 Env<GenContext> switchEnv = env.dup(tree, new GenContext());
1145 switchEnv.info.isSwitch = true;
1146
1147 // Compute number of labels and minimum and maximum label values.
1148 // For each case, store its label in an array.
1149 int lo = Integer.MAX_VALUE; // minimum label.
1150 int hi = Integer.MIN_VALUE; // maximum label.
1151 int nlabels = 0; // number of labels.
1152
1153 int[] labels = new int[cases.length()]; // the label array.
1154 int defaultIndex = -1; // the index of the default clause.
1155
1156 List<JCCase> l = cases;
1157 for (int i = 0; i < labels.length; i++) {
1158 if (l.head.pat != null) {
1159 int val = ((Number)l.head.pat.type.constValue()).intValue();
1160 labels[i] = val;
1161 if (val < lo) lo = val;
1162 if (hi < val) hi = val;
1163 nlabels++;
1164 } else {
1165 Assert.check(defaultIndex == -1);
1166 defaultIndex = i;
1167 }
1168 l = l.tail;
1169 }
1170
1171 // Determine whether to issue a tableswitch or a lookupswitch
1172 // instruction.
1173 long table_space_cost = 4 + ((long) hi - lo + 1); // words
1174 long table_time_cost = 3; // comparisons
1175 long lookup_space_cost = 3 + 2 * (long) nlabels;
1176 long lookup_time_cost = nlabels;
1177 int opcode =
1178 nlabels > 0 &&
1179 table_space_cost + 3 * table_time_cost <=
1180 lookup_space_cost + 3 * lookup_time_cost
1181 ?
1182 tableswitch : lookupswitch;
1183
1184 int startpc = code.curCP(); // the position of the selector operation
1185 code.emitop0(opcode);
1186 code.align(4);
1187 int tableBase = code.curCP(); // the start of the jump table
1188 int[] offsets = null; // a table of offsets for a lookupswitch
1189 code.emit4(-1); // leave space for default offset
1190 if (opcode == tableswitch) {
1191 code.emit4(lo); // minimum label
1192 code.emit4(hi); // maximum label
1193 for (long i = lo; i <= hi; i++) { // leave space for jump table
1194 code.emit4(-1);
1195 }
1196 } else {
1197 code.emit4(nlabels); // number of labels
1198 for (int i = 0; i < nlabels; i++) {
1199 code.emit4(-1); code.emit4(-1); // leave space for lookup table
1200 }
1201 offsets = new int[labels.length];
1202 }
1203 Code.State stateSwitch = code.state.dup();
1204 code.markDead();
1205
1206 // For each case do:
1207 l = cases;
1208 for (int i = 0; i < labels.length; i++) {
1209 JCCase c = l.head;
1210 l = l.tail;
1211
1212 int pc = code.entryPoint(stateSwitch);
1213 // Insert offset directly into code or else into the
1214 // offsets table.
1215 if (i != defaultIndex) {
1216 if (opcode == tableswitch) {
1217 code.put4(
1218 tableBase + 4 * (labels[i] - lo + 3),
1219 pc - startpc);
1220 } else {
1221 offsets[i] = pc - startpc;
1222 }
1223 } else {
1224 code.put4(tableBase, pc - startpc);
1225 }
1226
1227 // Generate code for the statements in this case.
1228 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1229 }
1230
1231 // Resolve all breaks.
1232 Chain exit = switchEnv.info.exit;
1233 if (exit != null) {
1234 code.resolve(exit);
1235 exit.state.defined.excludeFrom(code.nextreg);
1236 }
1237
1238 // If we have not set the default offset, we do so now.
1239 if (code.get4(tableBase) == -1) {
1240 code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
1241 }
1242
1243 if (opcode == tableswitch) {
1244 // Let any unfilled slots point to the default case.
1245 int defaultOffset = code.get4(tableBase);
1246 for (long i = lo; i <= hi; i++) {
1247 int t = (int)(tableBase + 4 * (i - lo + 3));
1248 if (code.get4(t) == -1)
1249 code.put4(t, defaultOffset);
1250 }
1251 } else {
1252 // Sort non-default offsets and copy into lookup table.
1253 if (defaultIndex >= 0)
1254 for (int i = defaultIndex; i < labels.length - 1; i++) {
1255 labels[i] = labels[i+1];
1256 offsets[i] = offsets[i+1];
1257 }
1258 if (nlabels > 0)
1259 qsort2(labels, offsets, 0, nlabels - 1);
1260 for (int i = 0; i < nlabels; i++) {
1261 int caseidx = tableBase + 8 * (i + 1);
1262 code.put4(caseidx, labels[i]);
1263 code.put4(caseidx + 4, offsets[i]);
1264 }
1265 }
1266 }
1267 code.endScopes(limit);
1268 }
1269 //where
1270 /** Sort (int) arrays of keys and values
1271 */
1272 static void qsort2(int[] keys, int[] values, int lo, int hi) {
1273 int i = lo;
1274 int j = hi;
1275 int pivot = keys[(i+j)/2];
1276 do {
1277 while (keys[i] < pivot) i++;
1278 while (pivot < keys[j]) j--;
1279 if (i <= j) {
1280 int temp1 = keys[i];
1281 keys[i] = keys[j];
1282 keys[j] = temp1;
1283 int temp2 = values[i];
1284 values[i] = values[j];
1285 values[j] = temp2;
1286 i++;
1287 j--;
1288 }
1289 } while (i <= j);
1290 if (lo < j) qsort2(keys, values, lo, j);
1291 if (i < hi) qsort2(keys, values, i, hi);
1292 }
1293
1294 public void visitSynchronized(JCSynchronized tree) {
1295 int limit = code.nextreg;
1296 // Generate code to evaluate lock and save in temporary variable.
1297 final LocalItem lockVar = makeTemp(syms.objectType);
1298 genExpr(tree.lock, tree.lock.type).load().duplicate();
1299 lockVar.store();
1300
1301 // Generate code to enter monitor.
1302 code.emitop0(monitorenter);
1303 code.state.lock(lockVar.reg);
1304
1305 // Generate code for a try statement with given body, no catch clauses
1306 // in a new environment with the "exit-monitor" operation as finalizer.
1307 final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
1308 syncEnv.info.finalize = new GenFinalizer() {
1309 void gen() {
1310 genLast();
1311 Assert.check(syncEnv.info.gaps.length() % 2 == 0);
1312 syncEnv.info.gaps.append(code.curCP());
1313 }
1314 void genLast() {
1315 if (code.isAlive()) {
1316 lockVar.load();
1317 code.emitop0(monitorexit);
1318 code.state.unlock(lockVar.reg);
1319 }
1320 }
1321 };
1322 syncEnv.info.gaps = new ListBuffer<>();
1323 genTry(tree.body, List.<JCCatch>nil(), syncEnv);
1324 code.endScopes(limit);
1325 }
1326
1327 public void visitTry(final JCTry tree) {
1328 // Generate code for a try statement with given body and catch clauses,
1329 // in a new environment which calls the finally block if there is one.
1330 final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
1331 final Env<GenContext> oldEnv = env;
1332 if (!useJsrLocally) {
1333 useJsrLocally =
1334 (stackMap == StackMapFormat.NONE) &&
1335 (jsrlimit <= 0 ||
1336 jsrlimit < 100 &&
1337 estimateCodeComplexity(tree.finalizer)>jsrlimit);
1338 }
1339 tryEnv.info.finalize = new GenFinalizer() {
1340 void gen() {
1341 if (useJsrLocally) {
1342 if (tree.finalizer != null) {
1343 Code.State jsrState = code.state.dup();
1344 jsrState.push(Code.jsrReturnValue);
1345 tryEnv.info.cont =
1346 new Chain(code.emitJump(jsr),
1347 tryEnv.info.cont,
1348 jsrState);
1349 }
1350 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1351 tryEnv.info.gaps.append(code.curCP());
1352 } else {
1353 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1354 tryEnv.info.gaps.append(code.curCP());
1355 genLast();
1356 }
1357 }
1358 void genLast() {
1359 if (tree.finalizer != null)
1360 genStat(tree.finalizer, oldEnv, CRT_BLOCK);
1361 }
1362 boolean hasFinalizer() {
1363 return tree.finalizer != null;
1364 }
1365 };
1366 tryEnv.info.gaps = new ListBuffer<>();
1367 genTry(tree.body, tree.catchers, tryEnv);
1368 }
1369 //where
1370 /** Generate code for a try or synchronized statement
1371 * @param body The body of the try or synchronized statement.
1372 * @param catchers The lis of catch clauses.
1373 * @param env the environment current for the body.
1374 */
1375 void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1376 int limit = code.nextreg;
1377 int startpc = code.curCP();
1378 Code.State stateTry = code.state.dup();
1379 genStat(body, env, CRT_BLOCK);
1380 int endpc = code.curCP();
1381 boolean hasFinalizer =
1382 env.info.finalize != null &&
1383 env.info.finalize.hasFinalizer();
1384 List<Integer> gaps = env.info.gaps.toList();
1385 code.statBegin(TreeInfo.endPos(body));
1386 genFinalizer(env);
1387 code.statBegin(TreeInfo.endPos(env.tree));
1388 Chain exitChain = code.branch(goto_);
1389 endFinalizerGap(env);
1390 if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1391 // start off with exception on stack
1392 code.entryPoint(stateTry, l.head.param.sym.type);
1393 genCatch(l.head, env, startpc, endpc, gaps);
1394 genFinalizer(env);
1395 if (hasFinalizer || l.tail.nonEmpty()) {
1396 code.statBegin(TreeInfo.endPos(env.tree));
1397 exitChain = Code.mergeChains(exitChain,
1398 code.branch(goto_));
1399 }
1400 endFinalizerGap(env);
1401 }
1402 if (hasFinalizer) {
1403 // Create a new register segement to avoid allocating
1404 // the same variables in finalizers and other statements.
1405 code.newRegSegment();
1406
1407 // Add a catch-all clause.
1408
1409 // start off with exception on stack
1410 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1411
1412 // Register all exception ranges for catch all clause.
1413 // The range of the catch all clause is from the beginning
1414 // of the try or synchronized block until the present
1415 // code pointer excluding all gaps in the current
1416 // environment's GenContext.
1417 int startseg = startpc;
1418 while (env.info.gaps.nonEmpty()) {
1419 int endseg = env.info.gaps.next().intValue();
1420 registerCatch(body.pos(), startseg, endseg,
1421 catchallpc, 0);
1422 startseg = env.info.gaps.next().intValue();
1423 }
1424 code.statBegin(TreeInfo.finalizerPos(env.tree));
1425 code.markStatBegin();
1426
1427 Item excVar = makeTemp(syms.throwableType);
1428 excVar.store();
1429 genFinalizer(env);
1430 excVar.load();
1431 registerCatch(body.pos(), startseg,
1432 env.info.gaps.next().intValue(),
1433 catchallpc, 0);
1434 code.emitop0(athrow);
1435 code.markDead();
1436
1437 // If there are jsr's to this finalizer, ...
1438 if (env.info.cont != null) {
1439 // Resolve all jsr's.
1440 code.resolve(env.info.cont);
1441
1442 // Mark statement line number
1443 code.statBegin(TreeInfo.finalizerPos(env.tree));
1444 code.markStatBegin();
1445
1446 // Save return address.
1447 LocalItem retVar = makeTemp(syms.throwableType);
1448 retVar.store();
1449
1450 // Generate finalizer code.
1451 env.info.finalize.genLast();
1452
1453 // Return.
1454 code.emitop1w(ret, retVar.reg);
1455 code.markDead();
1456 }
1457 }
1458 // Resolve all breaks.
1459 code.resolve(exitChain);
1460
1461 code.endScopes(limit);
1462 }
1463
1464 /** Generate code for a catch clause.
1465 * @param tree The catch clause.
1466 * @param env The environment current in the enclosing try.
1467 * @param startpc Start pc of try-block.
1468 * @param endpc End pc of try-block.
1469 */
1470 void genCatch(JCCatch tree,
1471 Env<GenContext> env,
1472 int startpc, int endpc,
1473 List<Integer> gaps) {
1474 if (startpc != endpc) {
1475 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypeExprs
1476 = catchTypesWithAnnotations(tree);
1477 while (gaps.nonEmpty()) {
1478 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1479 JCExpression subCatch = subCatch1.snd;
1480 int catchType = makeRef(tree.pos(), subCatch.type);
1481 int end = gaps.head.intValue();
1482 registerCatch(tree.pos(),
1483 startpc, end, code.curCP(),
1484 catchType);
1485 for (Attribute.TypeCompound tc : subCatch1.fst) {
1486 tc.position.setCatchInfo(catchType, startpc);
1487 }
1488 }
1489 gaps = gaps.tail;
1490 startpc = gaps.head.intValue();
1491 gaps = gaps.tail;
1492 }
1493 if (startpc < endpc) {
1494 for (Pair<List<Attribute.TypeCompound>, JCExpression> subCatch1 : catchTypeExprs) {
1495 JCExpression subCatch = subCatch1.snd;
1496 int catchType = makeRef(tree.pos(), subCatch.type);
1497 registerCatch(tree.pos(),
1498 startpc, endpc, code.curCP(),
1499 catchType);
1500 for (Attribute.TypeCompound tc : subCatch1.fst) {
1501 tc.position.setCatchInfo(catchType, startpc);
1502 }
1503 }
1504 }
1505 VarSymbol exparam = tree.param.sym;
1506 code.statBegin(tree.pos);
1507 code.markStatBegin();
1508 int limit = code.nextreg;
1509 code.newLocal(exparam);
1510 items.makeLocalItem(exparam).store();
1511 code.statBegin(TreeInfo.firstStatPos(tree.body));
1512 genStat(tree.body, env, CRT_BLOCK);
1513 code.endScopes(limit);
1514 code.statBegin(TreeInfo.endPos(tree.body));
1515 }
1516 }
1517 // where
1518 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotations(JCCatch tree) {
1519 return TreeInfo.isMultiCatch(tree) ?
1520 catchTypesWithAnnotationsFromMulticatch((JCTypeUnion)tree.param.vartype, tree.param.sym.getRawTypeAttributes()) :
1521 List.of(new Pair<>(tree.param.sym.getRawTypeAttributes(), tree.param.vartype));
1522 }
1523 // where
1524 List<Pair<List<Attribute.TypeCompound>, JCExpression>> catchTypesWithAnnotationsFromMulticatch(JCTypeUnion tree, List<TypeCompound> first) {
1525 List<JCExpression> alts = tree.alternatives;
1526 List<Pair<List<TypeCompound>, JCExpression>> res = List.of(new Pair<>(first, alts.head));
1527 alts = alts.tail;
1528
1529 while(alts != null && alts.head != null) {
1530 JCExpression alt = alts.head;
1531 if (alt instanceof JCAnnotatedType) {
1532 JCAnnotatedType a = (JCAnnotatedType)alt;
1533 res = res.prepend(new Pair<>(annotate.fromAnnotations(a.annotations), alt));
1534 } else {
1535 res = res.prepend(new Pair<>(List.nil(), alt));
1536 }
1537 alts = alts.tail;
1538 }
1539 return res.reverse();
1540 }
1541
1542 /** Register a catch clause in the "Exceptions" code-attribute.
1543 */
1544 void registerCatch(DiagnosticPosition pos,
1545 int startpc, int endpc,
1546 int handler_pc, int catch_type) {
1547 char startpc1 = (char)startpc;
1548 char endpc1 = (char)endpc;
1549 char handler_pc1 = (char)handler_pc;
1550 if (startpc1 == startpc &&
1551 endpc1 == endpc &&
1552 handler_pc1 == handler_pc) {
1553 code.addCatch(startpc1, endpc1, handler_pc1,
1554 (char)catch_type);
1555 } else {
1556 log.error(pos, "limit.code.too.large.for.try.stmt");
1557 nerrs++;
1558 }
1559 }
1560
1561 /** Very roughly estimate the number of instructions needed for
1562 * the given tree.
1563 */
1564 int estimateCodeComplexity(JCTree tree) {
1565 if (tree == null) return 0;
1566 class ComplexityScanner extends TreeScanner {
1567 int complexity = 0;
1568 public void scan(JCTree tree) {
1569 if (complexity > jsrlimit) return;
1570 super.scan(tree);
1571 }
1572 public void visitClassDef(JCClassDecl tree) {}
1573 public void visitDoLoop(JCDoWhileLoop tree)
1574 { super.visitDoLoop(tree); complexity++; }
1575 public void visitWhileLoop(JCWhileLoop tree)
1576 { super.visitWhileLoop(tree); complexity++; }
1577 public void visitForLoop(JCForLoop tree)
1578 { super.visitForLoop(tree); complexity++; }
1579 public void visitSwitch(JCSwitch tree)
1580 { super.visitSwitch(tree); complexity+=5; }
1581 public void visitCase(JCCase tree)
1582 { super.visitCase(tree); complexity++; }
1583 public void visitSynchronized(JCSynchronized tree)
1584 { super.visitSynchronized(tree); complexity+=6; }
1585 public void visitTry(JCTry tree)
1586 { super.visitTry(tree);
1587 if (tree.finalizer != null) complexity+=6; }
1588 public void visitCatch(JCCatch tree)
1589 { super.visitCatch(tree); complexity+=2; }
1590 public void visitConditional(JCConditional tree)
1591 { super.visitConditional(tree); complexity+=2; }
1592 public void visitIf(JCIf tree)
1593 { super.visitIf(tree); complexity+=2; }
1594 // note: for break, continue, and return we don't take unwind() into account.
1595 public void visitBreak(JCBreak tree)
1596 { super.visitBreak(tree); complexity+=1; }
1597 public void visitContinue(JCContinue tree)
1598 { super.visitContinue(tree); complexity+=1; }
1599 public void visitReturn(JCReturn tree)
1600 { super.visitReturn(tree); complexity+=1; }
1601 public void visitThrow(JCThrow tree)
1602 { super.visitThrow(tree); complexity+=1; }
1603 public void visitAssert(JCAssert tree)
1604 { super.visitAssert(tree); complexity+=5; }
1605 public void visitApply(JCMethodInvocation tree)
1606 { super.visitApply(tree); complexity+=2; }
1607 public void visitNewClass(JCNewClass tree)
1608 { scan(tree.encl); scan(tree.args); complexity+=2; }
1609 public void visitNewArray(JCNewArray tree)
1610 { super.visitNewArray(tree); complexity+=5; }
1611 public void visitAssign(JCAssign tree)
1612 { super.visitAssign(tree); complexity+=1; }
1613 public void visitAssignop(JCAssignOp tree)
1614 { super.visitAssignop(tree); complexity+=2; }
1615 public void visitUnary(JCUnary tree)
1616 { complexity+=1;
1617 if (tree.type.constValue() == null) super.visitUnary(tree); }
1618 public void visitBinary(JCBinary tree)
1619 { complexity+=1;
1620 if (tree.type.constValue() == null) super.visitBinary(tree); }
1621 public void visitTypeTest(JCInstanceOf tree)
1622 { super.visitTypeTest(tree); complexity+=1; }
1623 public void visitIndexed(JCArrayAccess tree)
1624 { super.visitIndexed(tree); complexity+=1; }
1625 public void visitSelect(JCFieldAccess tree)
1626 { super.visitSelect(tree);
1627 if (tree.sym.kind == VAR) complexity+=1; }
1628 public void visitIdent(JCIdent tree) {
1629 if (tree.sym.kind == VAR) {
1630 complexity+=1;
1631 if (tree.type.constValue() == null &&
1632 tree.sym.owner.kind == TYP)
1633 complexity+=1;
1634 }
1635 }
1636 public void visitLiteral(JCLiteral tree)
1637 { complexity+=1; }
1638 public void visitTree(JCTree tree) {}
1639 public void visitWildcard(JCWildcard tree) {
1640 throw new AssertionError(this.getClass().getName());
1641 }
1642 }
1643 ComplexityScanner scanner = new ComplexityScanner();
1644 tree.accept(scanner);
1645 return scanner.complexity;
1646 }
1647
1648 public void visitIf(JCIf tree) {
1649 int limit = code.nextreg;
1650 Chain thenExit = null;
1651 CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1652 CRT_FLOW_CONTROLLER);
1653 Chain elseChain = c.jumpFalse();
1654 if (!c.isFalse()) {
1655 code.resolve(c.trueJumps);
1656 genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1657 thenExit = code.branch(goto_);
1658 }
1659 if (elseChain != null) {
1660 code.resolve(elseChain);
1661 if (tree.elsepart != null) {
1662 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1663 }
1664 }
1665 code.resolve(thenExit);
1666 code.endScopes(limit);
1667 }
1668
1669 public void visitExec(JCExpressionStatement tree) {
1670 // Optimize x++ to ++x and x-- to --x.
1671 JCExpression e = tree.expr;
1672 switch (e.getTag()) {
1673 case POSTINC:
1674 ((JCUnary) e).setTag(PREINC);
1675 break;
1676 case POSTDEC:
1677 ((JCUnary) e).setTag(PREDEC);
1678 break;
1679 }
1680 genExpr(tree.expr, tree.expr.type).drop();
1681 }
1682
1683 public void visitBreak(JCBreak tree) {
1684 Env<GenContext> targetEnv = unwind(tree.target, env);
1685 Assert.check(code.state.stacksize == 0);
1686 targetEnv.info.addExit(code.branch(goto_));
1687 endFinalizerGaps(env, targetEnv);
1688 }
1689
1690 public void visitContinue(JCContinue tree) {
1691 Env<GenContext> targetEnv = unwind(tree.target, env);
1692 Assert.check(code.state.stacksize == 0);
1693 targetEnv.info.addCont(code.branch(goto_));
1694 endFinalizerGaps(env, targetEnv);
1695 }
1696
1697 public void visitReturn(JCReturn tree) {
1698 int limit = code.nextreg;
1699 final Env<GenContext> targetEnv;
1700
1701 /* Save and then restore the location of the return in case a finally
1702 * is expanded (with unwind()) in the middle of our bytecodes.
1703 */
1704 int tmpPos = code.pendingStatPos;
1705 if (tree.expr != null) {
1706 Item r = genExpr(tree.expr, pt).load();
1707 if (hasFinally(env.enclMethod, env)) {
1708 r = makeTemp(pt);
1709 r.store();
1710 }
1711 targetEnv = unwind(env.enclMethod, env);
1712 code.pendingStatPos = tmpPos;
1713 r.load();
1714 code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
1715 } else {
1716 targetEnv = unwind(env.enclMethod, env);
1717 code.pendingStatPos = tmpPos;
1718 code.emitop0(return_);
1719 }
1720 endFinalizerGaps(env, targetEnv);
1721 code.endScopes(limit);
1722 }
1723
1724 public void visitThrow(JCThrow tree) {
1725 genExpr(tree.expr, tree.expr.type).load();
1726 code.emitop0(athrow);
1727 }
1728
1729 /* ************************************************************************
1730 * Visitor methods for expressions
1731 *************************************************************************/
1732
1733 public void visitApply(JCMethodInvocation tree) {
1734 setTypeAnnotationPositions(tree.pos);
1735 // Generate code for method.
1736 Item m = genExpr(tree.meth, methodType);
1737 // Generate code for all arguments, where the expected types are
1738 // the parameters of the method's external type (that is, any implicit
1739 // outer instance of a super(...) call appears as first parameter).
1740 MethodSymbol msym = (MethodSymbol)TreeInfo.symbol(tree.meth);
1741 genArgs(tree.args,
1742 msym.externalType(types).getParameterTypes());
1743 if (!msym.isDynamic()) {
1744 code.statBegin(tree.pos);
1745 }
1746 result = m.invoke();
1747 }
1748
1749 public void visitConditional(JCConditional tree) {
1750 Chain thenExit = null;
1751 CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
1752 Chain elseChain = c.jumpFalse();
1753 if (!c.isFalse()) {
1754 code.resolve(c.trueJumps);
1755 int startpc = genCrt ? code.curCP() : 0;
1756 code.statBegin(tree.truepart.pos);
1757 genExpr(tree.truepart, pt).load();
1758 code.state.forceStackTop(tree.type);
1759 if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
1760 startpc, code.curCP());
1761 thenExit = code.branch(goto_);
1762 }
1763 if (elseChain != null) {
1764 code.resolve(elseChain);
1765 int startpc = genCrt ? code.curCP() : 0;
1766 code.statBegin(tree.falsepart.pos);
1767 genExpr(tree.falsepart, pt).load();
1768 code.state.forceStackTop(tree.type);
1769 if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
1770 startpc, code.curCP());
1771 }
1772 code.resolve(thenExit);
1773 result = items.makeStackItem(pt);
1774 }
1775
1776 private void setTypeAnnotationPositions(int treePos) {
1777 MethodSymbol meth = code.meth;
1778 boolean initOrClinit = code.meth.getKind() == javax.lang.model.element.ElementKind.CONSTRUCTOR
1779 || code.meth.getKind() == javax.lang.model.element.ElementKind.STATIC_INIT;
1780
1781 for (Attribute.TypeCompound ta : meth.getRawTypeAttributes()) {
1782 if (ta.hasUnknownPosition())
1783 ta.tryFixPosition();
1784
1785 if (ta.position.matchesPos(treePos))
1786 ta.position.updatePosOffset(code.cp);
1787 }
1788
1789 if (!initOrClinit)
1790 return;
1791
1792 for (Attribute.TypeCompound ta : meth.owner.getRawTypeAttributes()) {
1793 if (ta.hasUnknownPosition())
1794 ta.tryFixPosition();
1795
1796 if (ta.position.matchesPos(treePos))
1797 ta.position.updatePosOffset(code.cp);
1798 }
1799
1800 ClassSymbol clazz = meth.enclClass();
1801 for (Symbol s : new com.sun.tools.javac.model.FilteredMemberList(clazz.members())) {
1802 if (!s.getKind().isField())
1803 continue;
1804
1805 for (Attribute.TypeCompound ta : s.getRawTypeAttributes()) {
1806 if (ta.hasUnknownPosition())
1807 ta.tryFixPosition();
1808
1809 if (ta.position.matchesPos(treePos))
1810 ta.position.updatePosOffset(code.cp);
1811 }
1812 }
1813 }
1814
1815 public void visitNewClass(JCNewClass tree) {
1816 // Enclosing instances or anonymous classes should have been eliminated
1817 // by now.
1818 Assert.check(tree.encl == null && tree.def == null);
1819 setTypeAnnotationPositions(tree.pos);
1820
1821 code.emitop2(new_, makeRef(tree.pos(), tree.type));
1822 code.emitop0(dup);
1823
1824 // Generate code for all arguments, where the expected types are
1825 // the parameters of the constructor's external type (that is,
1826 // any implicit outer instance appears as first parameter).
1827 genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
1828
1829 items.makeMemberItem(tree.constructor, true).invoke();
1830 result = items.makeStackItem(tree.type);
1831 }
1832
1833 public void visitNewArray(JCNewArray tree) {
1834 setTypeAnnotationPositions(tree.pos);
1835
1836 if (tree.elems != null) {
1837 Type elemtype = types.elemtype(tree.type);
1838 loadIntConst(tree.elems.length());
1839 Item arr = makeNewArray(tree.pos(), tree.type, 1);
1840 int i = 0;
1841 for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
1842 arr.duplicate();
1843 loadIntConst(i);
1844 i++;
1845 genExpr(l.head, elemtype).load();
1846 items.makeIndexedItem(elemtype).store();
1847 }
1848 result = arr;
1849 } else {
1850 for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
1851 genExpr(l.head, syms.intType).load();
1852 }
1853 result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
1854 }
1855 }
1856 //where
1857 /** Generate code to create an array with given element type and number
1858 * of dimensions.
1859 */
1860 Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
1861 Type elemtype = types.elemtype(type);
1862 if (types.dimensions(type) > ClassFile.MAX_DIMENSIONS) {
1863 log.error(pos, "limit.dimensions");
1864 nerrs++;
1865 }
1866 int elemcode = Code.arraycode(elemtype);
1867 if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
1868 code.emitAnewarray(makeRef(pos, elemtype), type);
1869 } else if (elemcode == 1) {
1870 code.emitMultianewarray(ndims, makeRef(pos, type), type);
1871 } else {
1872 code.emitNewarray(elemcode, type);
1873 }
1874 return items.makeStackItem(type);
1875 }
1876
1877 public void visitParens(JCParens tree) {
1878 result = genExpr(tree.expr, tree.expr.type);
1879 }
1880
1881 public void visitAssign(JCAssign tree) {
1882 Item l = genExpr(tree.lhs, tree.lhs.type);
1883 genExpr(tree.rhs, tree.lhs.type).load();
1884 if (tree.rhs.type.hasTag(BOT)) {
1885 /* This is just a case of widening reference conversion that per 5.1.5 simply calls
1886 for "regarding a reference as having some other type in a manner that can be proved
1887 correct at compile time."
1888 */
1889 code.state.forceStackTop(tree.lhs.type);
1890 }
1891 result = items.makeAssignItem(l);
1892 }
1893
1894 public void visitAssignop(JCAssignOp tree) {
1895 OperatorSymbol operator = (OperatorSymbol) tree.operator;
1896 Item l;
1897 if (operator.opcode == string_add) {
1898 // Generate code to make a string buffer
1899 makeStringBuffer(tree.pos());
1900
1901 // Generate code for first string, possibly save one
1902 // copy under buffer
1903 l = genExpr(tree.lhs, tree.lhs.type);
1904 if (l.width() > 0) {
1905 code.emitop0(dup_x1 + 3 * (l.width() - 1));
1906 }
1907
1908 // Load first string and append to buffer.
1909 l.load();
1910 appendString(tree.lhs);
1911
1912 // Append all other strings to buffer.
1913 appendStrings(tree.rhs);
1914
1915 // Convert buffer to string.
1916 bufferToString(tree.pos());
1917 } else {
1918 // Generate code for first expression
1919 l = genExpr(tree.lhs, tree.lhs.type);
1920
1921 // If we have an increment of -32768 to +32767 of a local
1922 // int variable we can use an incr instruction instead of
1923 // proceeding further.
1924 if ((tree.hasTag(PLUS_ASG) || tree.hasTag(MINUS_ASG)) &&
1925 l instanceof LocalItem &&
1926 tree.lhs.type.getTag().isSubRangeOf(INT) &&
1927 tree.rhs.type.getTag().isSubRangeOf(INT) &&
1928 tree.rhs.type.constValue() != null) {
1929 int ival = ((Number) tree.rhs.type.constValue()).intValue();
1930 if (tree.hasTag(MINUS_ASG)) ival = -ival;
1931 ((LocalItem)l).incr(ival);
1932 result = l;
1933 return;
1934 }
1935 // Otherwise, duplicate expression, load one copy
1936 // and complete binary operation.
1937 l.duplicate();
1938 l.coerce(operator.type.getParameterTypes().head).load();
1939 completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
1940 }
1941 result = items.makeAssignItem(l);
1942 }
1943
1944 public void visitUnary(JCUnary tree) {
1945 OperatorSymbol operator = (OperatorSymbol)tree.operator;
1946 if (tree.hasTag(NOT)) {
1947 CondItem od = genCond(tree.arg, false);
1948 result = od.negate();
1949 } else {
1950 Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
1951 switch (tree.getTag()) {
1952 case POS:
1953 result = od.load();
1954 break;
1955 case NEG:
1956 result = od.load();
1957 code.emitop0(operator.opcode);
1958 break;
1959 case COMPL:
1960 result = od.load();
1961 emitMinusOne(od.typecode);
1962 code.emitop0(operator.opcode);
1963 break;
1964 case PREINC: case PREDEC:
1965 od.duplicate();
1966 if (od instanceof LocalItem &&
1967 (operator.opcode == iadd || operator.opcode == isub)) {
1968 ((LocalItem)od).incr(tree.hasTag(PREINC) ? 1 : -1);
1969 result = od;
1970 } else {
1971 od.load();
1972 code.emitop0(one(od.typecode));
1973 code.emitop0(operator.opcode);
1974 // Perform narrowing primitive conversion if byte,
1975 // char, or short. Fix for 4304655.
1976 if (od.typecode != INTcode &&
1977 Code.truncate(od.typecode) == INTcode)
1978 code.emitop0(int2byte + od.typecode - BYTEcode);
1979 result = items.makeAssignItem(od);
1980 }
1981 break;
1982 case POSTINC: case POSTDEC:
1983 od.duplicate();
1984 if (od instanceof LocalItem &&
1985 (operator.opcode == iadd || operator.opcode == isub)) {
1986 Item res = od.load();
1987 ((LocalItem)od).incr(tree.hasTag(POSTINC) ? 1 : -1);
1988 result = res;
1989 } else {
1990 Item res = od.load();
1991 od.stash(od.typecode);
1992 code.emitop0(one(od.typecode));
1993 code.emitop0(operator.opcode);
1994 // Perform narrowing primitive conversion if byte,
1995 // char, or short. Fix for 4304655.
1996 if (od.typecode != INTcode &&
1997 Code.truncate(od.typecode) == INTcode)
1998 code.emitop0(int2byte + od.typecode - BYTEcode);
1999 od.store();
2000 result = res;
2001 }
2002 break;
2003 case NULLCHK:
2004 result = od.load();
2005 code.emitop0(dup);
2006 genNullCheck(tree.pos());
2007 break;
2008 default:
2009 Assert.error();
2010 }
2011 }
2012 }
2013
2014 /** Generate a null check from the object value at stack top. */
2015 private void genNullCheck(DiagnosticPosition pos) {
2016 if (allowBetterNullChecks) {
2017 callMethod(pos, syms.objectsType, names.requireNonNull,
2018 List.of(syms.objectType), true);
2019 } else {
2020 callMethod(pos, syms.objectType, names.getClass,
2021 List.<Type>nil(), false);
2022 }
2023 code.emitop0(pop);
2024 }
2025
2026 public void visitBinary(JCBinary tree) {
2027 OperatorSymbol operator = (OperatorSymbol)tree.operator;
2028 if (operator.opcode == string_add) {
2029 // Create a string buffer.
2030 makeStringBuffer(tree.pos());
2031 // Append all strings to buffer.
2032 appendStrings(tree);
2033 // Convert buffer to string.
2034 bufferToString(tree.pos());
2035 result = items.makeStackItem(syms.stringType);
2036 } else if (tree.hasTag(AND)) {
2037 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
2038 if (!lcond.isFalse()) {
2039 Chain falseJumps = lcond.jumpFalse();
2040 code.resolve(lcond.trueJumps);
2041 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
2042 result = items.
2043 makeCondItem(rcond.opcode,
2044 rcond.trueJumps,
2045 Code.mergeChains(falseJumps,
2046 rcond.falseJumps));
2047 } else {
2048 result = lcond;
2049 }
2050 } else if (tree.hasTag(OR)) {
2051 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
2052 if (!lcond.isTrue()) {
2053 Chain trueJumps = lcond.jumpTrue();
2054 code.resolve(lcond.falseJumps);
2055 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
2056 result = items.
2057 makeCondItem(rcond.opcode,
2058 Code.mergeChains(trueJumps, rcond.trueJumps),
2059 rcond.falseJumps);
2060 } else {
2061 result = lcond;
2062 }
2063 } else {
2064 Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
2065 od.load();
2066 result = completeBinop(tree.lhs, tree.rhs, operator);
2067 }
2068 }
2069 //where
2070 /** Make a new string buffer.
2071 */
2072 void makeStringBuffer(DiagnosticPosition pos) {
2073 code.emitop2(new_, makeRef(pos, syms.stringBuilderType));
2074 code.emitop0(dup);
2075 callMethod(
2076 pos, syms.stringBuilderType, names.init, List.<Type>nil(), false);
2077 }
2078
2079 /** Append value (on tos) to string buffer (on tos - 1).
2080 */
2081 void appendString(JCTree tree) {
2082 Type t = tree.type.baseType();
2083 if (!t.isPrimitive() && t.tsym != syms.stringType.tsym) {
2084 t = syms.objectType;
2085 }
2086 items.makeMemberItem(getStringBufferAppend(tree, t), false).invoke();
2087 }
2088 Symbol getStringBufferAppend(JCTree tree, Type t) {
2089 Assert.checkNull(t.constValue());
2090 Symbol method = stringBufferAppend.get(t);
2091 if (method == null) {
2092 method = rs.resolveInternalMethod(tree.pos(),
2093 attrEnv,
2094 syms.stringBuilderType,
2095 names.append,
2096 List.of(t),
2097 null);
2098 stringBufferAppend.put(t, method);
2099 }
2100 return method;
2101 }
2102
2103 /** Add all strings in tree to string buffer.
2104 */
2105 void appendStrings(JCTree tree) {
2106 tree = TreeInfo.skipParens(tree);
2107 if (tree.hasTag(PLUS) && tree.type.constValue() == null) {
2108 JCBinary op = (JCBinary) tree;
2109 if (op.operator.kind == MTH &&
2110 ((OperatorSymbol) op.operator).opcode == string_add) {
2111 appendStrings(op.lhs);
2112 appendStrings(op.rhs);
2113 return;
2114 }
2115 }
2116 genExpr(tree, tree.type).load();
2117 appendString(tree);
2118 }
2119
2120 /** Convert string buffer on tos to string.
2121 */
2122 void bufferToString(DiagnosticPosition pos) {
2123 callMethod(
2124 pos,
2125 syms.stringBuilderType,
2126 names.toString,
2127 List.<Type>nil(),
2128 false);
2129 }
2130
2131 /** Complete generating code for operation, with left operand
2132 * already on stack.
2133 * @param lhs The tree representing the left operand.
2134 * @param rhs The tree representing the right operand.
2135 * @param operator The operator symbol.
2136 */
2137 Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
2138 MethodType optype = (MethodType)operator.type;
2139 int opcode = operator.opcode;
2140 if (opcode >= if_icmpeq && opcode <= if_icmple &&
2141 rhs.type.constValue() instanceof Number &&
2142 ((Number) rhs.type.constValue()).intValue() == 0) {
2143 opcode = opcode + (ifeq - if_icmpeq);
2144 } else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
2145 TreeInfo.isNull(rhs)) {
2146 opcode = opcode + (if_acmp_null - if_acmpeq);
2147 } else {
2148 // The expected type of the right operand is
2149 // the second parameter type of the operator, except for
2150 // shifts with long shiftcount, where we convert the opcode
2151 // to a short shift and the expected type to int.
2152 Type rtype = operator.erasure(types).getParameterTypes().tail.head;
2153 if (opcode >= ishll && opcode <= lushrl) {
2154 opcode = opcode + (ishl - ishll);
2155 rtype = syms.intType;
2156 }
2157 // Generate code for right operand and load.
2158 genExpr(rhs, rtype).load();
2159 // If there are two consecutive opcode instructions,
2160 // emit the first now.
2161 if (opcode >= (1 << preShift)) {
2162 code.emitop0(opcode >> preShift);
2163 opcode = opcode & 0xFF;
2164 }
2165 }
2166 if (opcode >= ifeq && opcode <= if_acmpne ||
2167 opcode == if_acmp_null || opcode == if_acmp_nonnull) {
2168 return items.makeCondItem(opcode);
2169 } else {
2170 code.emitop0(opcode);
2171 return items.makeStackItem(optype.restype);
2172 }
2173 }
2174
2175 public void visitTypeCast(JCTypeCast tree) {
2176 setTypeAnnotationPositions(tree.pos);
2177 result = genExpr(tree.expr, tree.clazz.type).load();
2178 // Additional code is only needed if we cast to a reference type
2179 // which is not statically a supertype of the expression's type.
2180 // For basic types, the coerce(...) in genExpr(...) will do
2181 // the conversion.
2182 if (!tree.clazz.type.isPrimitive() &&
2183 !types.isSameType(tree.expr.type, tree.clazz.type) &&
2184 types.asSuper(tree.expr.type, tree.clazz.type.tsym) == null) {
2185 code.emitop2(checkcast, makeRef(tree.pos(), tree.clazz.type));
2186 }
2187 }
2188
2189 public void visitWildcard(JCWildcard tree) {
2190 throw new AssertionError(this.getClass().getName());
2191 }
2192
2193 public void visitTypeTest(JCInstanceOf tree) {
2194 setTypeAnnotationPositions(tree.pos);
2195 genExpr(tree.expr, tree.expr.type).load();
2196 code.emitop2(instanceof_, makeRef(tree.pos(), tree.clazz.type));
2197 result = items.makeStackItem(syms.booleanType);
2198 }
2199
2200 public void visitIndexed(JCArrayAccess tree) {
2201 genExpr(tree.indexed, tree.indexed.type).load();
2202 genExpr(tree.index, syms.intType).load();
2203 result = items.makeIndexedItem(tree.type);
2204 }
2205
2206 public void visitIdent(JCIdent tree) {
2207 Symbol sym = tree.sym;
2208 if (tree.name == names._this || tree.name == names._super) {
2209 Item res = tree.name == names._this
2210 ? items.makeThisItem()
2211 : items.makeSuperItem();
2212 if (sym.kind == MTH) {
2213 // Generate code to address the constructor.
2214 res.load();
2215 res = items.makeMemberItem(sym, true);
2216 }
2217 result = res;
2218 } else if (sym.kind == VAR && sym.owner.kind == MTH) {
2219 result = items.makeLocalItem((VarSymbol)sym);
2220 } else if (isInvokeDynamic(sym)) {
2221 result = items.makeDynamicItem(sym);
2222 } else if ((sym.flags() & STATIC) != 0) {
2223 if (!isAccessSuper(env.enclMethod))
2224 sym = binaryQualifier(sym, env.enclClass.type);
2225 result = items.makeStaticItem(sym);
2226 } else {
2227 items.makeThisItem().load();
2228 sym = binaryQualifier(sym, env.enclClass.type);
2229 result = items.makeMemberItem(sym, (sym.flags() & PRIVATE) != 0);
2230 }
2231 }
2232
2233 public void visitSelect(JCFieldAccess tree) {
2234 Symbol sym = tree.sym;
2235
2236 if (tree.name == names._class) {
2237 code.emitLdc(makeRef(tree.pos(), tree.selected.type));
2238 result = items.makeStackItem(pt);
2239 return;
2240 }
2241
2242 Symbol ssym = TreeInfo.symbol(tree.selected);
2243
2244 // Are we selecting via super?
2245 boolean selectSuper =
2246 ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2247
2248 // Are we accessing a member of the superclass in an access method
2249 // resulting from a qualified super?
2250 boolean accessSuper = isAccessSuper(env.enclMethod);
2251
2252 Item base = (selectSuper)
2253 ? items.makeSuperItem()
2254 : genExpr(tree.selected, tree.selected.type);
2255
2256 if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2257 // We are seeing a variable that is constant but its selecting
2258 // expression is not.
2259 if ((sym.flags() & STATIC) != 0) {
2260 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2261 base = base.load();
2262 base.drop();
2263 } else {
2264 base.load();
2265 genNullCheck(tree.selected.pos());
2266 }
2267 result = items.
2268 makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
2269 } else {
2270 if (isInvokeDynamic(sym)) {
2271 result = items.makeDynamicItem(sym);
2272 return;
2273 } else {
2274 sym = binaryQualifier(sym, tree.selected.type);
2275 }
2276 if ((sym.flags() & STATIC) != 0) {
2277 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2278 base = base.load();
2279 base.drop();
2280 result = items.makeStaticItem(sym);
2281 } else {
2282 base.load();
2283 if (sym == syms.lengthVar) {
2284 code.emitop0(arraylength);
2285 result = items.makeStackItem(syms.intType);
2286 } else {
2287 result = items.
2288 makeMemberItem(sym,
2289 (sym.flags() & PRIVATE) != 0 ||
2290 selectSuper || accessSuper);
2291 }
2292 }
2293 }
2294 }
2295
2296 public boolean isInvokeDynamic(Symbol sym) {
2297 return sym.kind == MTH && ((MethodSymbol)sym).isDynamic();
2298 }
2299
2300 public void visitLiteral(JCLiteral tree) {
2301 if (tree.type.hasTag(BOT)) {
2302 code.emitop0(aconst_null);
2303 result = items.makeStackItem(tree.type);
2304 }
2305 else
2306 result = items.makeImmediateItem(tree.type, tree.value);
2307 }
2308
2309 public void visitLetExpr(LetExpr tree) {
2310 int limit = code.nextreg;
2311 genStats(tree.defs, env);
2312 result = genExpr(tree.expr, tree.expr.type).load();
2313 code.endScopes(limit);
2314 }
2315
2316 private void generateReferencesToPrunedTree(ClassSymbol classSymbol, Pool pool) {
2317 List<JCTree> prunedInfo = lower.prunedTree.get(classSymbol);
2318 if (prunedInfo != null) {
2319 for (JCTree prunedTree: prunedInfo) {
2320 prunedTree.accept(classReferenceVisitor);
2321 }
2322 }
2323 }
2324
2325 /* ************************************************************************
2326 * main method
2327 *************************************************************************/
2328
2329 /** Generate code for a class definition.
2330 * @param env The attribution environment that belongs to the
2331 * outermost class containing this class definition.
2332 * We need this for resolving some additional symbols.
2333 * @param cdef The tree representing the class definition.
2334 * @return True if code is generated with no errors.
2335 */
2336 public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
2337 try {
2338 attrEnv = env;
2339 ClassSymbol c = cdef.sym;
2340 this.toplevel = env.toplevel;
2341 this.endPosTable = toplevel.endPositions;
2342 c.pool = pool;
2343 pool.reset();
2344 /* method normalizeDefs() can add references to external classes into the constant pool
2345 */
2346 cdef.defs = normalizeDefs(cdef.defs, c);
2347 generateReferencesToPrunedTree(c, pool);
2348 Env<GenContext> localEnv = new Env<>(cdef, new GenContext());
2349 localEnv.toplevel = env.toplevel;
2350 localEnv.enclClass = cdef;
2351
2352 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2353 genDef(l.head, localEnv);
2354 }
2355 if (pool.numEntries() > Pool.MAX_ENTRIES) {
2356 log.error(cdef.pos(), "limit.pool");
2357 nerrs++;
2358 }
2359 if (nerrs != 0) {
2360 // if errors, discard code
2361 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2362 if (l.head.hasTag(METHODDEF))
2363 ((JCMethodDecl) l.head).sym.code = null;
2364 }
2365 }
2366 cdef.defs = List.nil(); // discard trees
2367 return nerrs == 0;
2368 } finally {
2369 // note: this method does NOT support recursion.
2370 attrEnv = null;
2371 this.env = null;
2372 toplevel = null;
2373 endPosTable = null;
2374 nerrs = 0;
2375 }
2376 }
2377
2378 /* ************************************************************************
2379 * Auxiliary classes
2380 *************************************************************************/
2381
2382 /** An abstract class for finalizer generation.
2383 */
2384 abstract class GenFinalizer {
2385 /** Generate code to clean up when unwinding. */
2386 abstract void gen();
2387
2388 /** Generate code to clean up at last. */
2389 abstract void genLast();
2390
2391 /** Does this finalizer have some nontrivial cleanup to perform? */
2392 boolean hasFinalizer() { return true; }
2393 }
2394
2395 /** code generation contexts,
2396 * to be used as type parameter for environments.
2397 */
2398 static class GenContext {
2399
2400 /** A chain for all unresolved jumps that exit the current environment.
2401 */
2402 Chain exit = null;
2403
2404 /** A chain for all unresolved jumps that continue in the
2405 * current environment.
2406 */
2407 Chain cont = null;
2408
2409 /** A closure that generates the finalizer of the current environment.
2410 * Only set for Synchronized and Try contexts.
2411 */
2412 GenFinalizer finalize = null;
2413
2414 /** Is this a switch statement? If so, allocate registers
2415 * even when the variable declaration is unreachable.
2416 */
2417 boolean isSwitch = false;
2418
2419 /** A list buffer containing all gaps in the finalizer range,
2420 * where a catch all exception should not apply.
2421 */
2422 ListBuffer<Integer> gaps = null;
2423
2424 /** Add given chain to exit chain.
2425 */
2426 void addExit(Chain c) {
2427 exit = Code.mergeChains(c, exit);
2428 }
2429
2430 /** Add given chain to cont chain.
2431 */
2432 void addCont(Chain c) {
2433 cont = Code.mergeChains(c, cont);
2434 }
2435 }
2436
2437 }