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