1 /*
2 * Copyright (c) 1999, 2011, 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 import java.util.*;
28
29 import javax.lang.model.element.ElementKind;
30
31 import com.sun.tools.javac.util.*;
32 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
33 import com.sun.tools.javac.util.List;
34 import com.sun.tools.javac.code.*;
35 import com.sun.tools.javac.comp.*;
36 import com.sun.tools.javac.tree.*;
37
38 import com.sun.tools.javac.code.Symbol.*;
39 import com.sun.tools.javac.code.Type.*;
40 import com.sun.tools.javac.jvm.Code.*;
41 import com.sun.tools.javac.jvm.Items.*;
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.*;
46 import static com.sun.tools.javac.code.TypeTags.*;
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.OptionName.*;
50
51 /** This pass maps flat Java (i.e. without inner classes) to bytecodes.
52 *
53 * <p><b>This is NOT part of any supported API.
54 * If you write code that depends on this, you do so at your own risk.
55 * This code and its internal interfaces are subject to change or
56 * deletion without notice.</b>
57 */
58 public class Gen extends JCTree.Visitor {
59 protected static final Context.Key<Gen> genKey =
60 new Context.Key<Gen>();
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 final Type stringBufferType;
70 private final Map<Type,Symbol> stringBufferAppend;
71 private Name accessDollar;
72 private final Types types;
73
74 /** Switch: GJ mode?
75 */
76 private final boolean allowGenerics;
77
78 /** Set when Miranda method stubs are to be generated. */
79 private final boolean generateIproxies;
80
81 /** Format of stackmap tables to be generated. */
82 private final Code.StackMapFormat stackMap;
83
84 /** A type that serves as the expected type for all method expressions.
85 */
86 private final Type methodType;
87
88 public static Gen instance(Context context) {
89 Gen instance = context.get(genKey);
90 if (instance == null)
91 instance = new Gen(context);
92 return instance;
93 }
94
95 protected Gen(Context context) {
96 context.put(genKey, this);
97
98 names = Names.instance(context);
99 log = Log.instance(context);
100 syms = Symtab.instance(context);
101 chk = Check.instance(context);
102 rs = Resolve.instance(context);
103 make = TreeMaker.instance(context);
104 target = Target.instance(context);
105 types = Types.instance(context);
106 methodType = new MethodType(null, null, null, syms.methodClass);
107 allowGenerics = Source.instance(context).allowGenerics();
108 stringBufferType = target.useStringBuilder()
109 ? syms.stringBuilderType
110 : syms.stringBufferType;
111 stringBufferAppend = new HashMap<Type,Symbol>();
112 accessDollar = names.
113 fromString("access" + target.syntheticNameChar());
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
127 generateIproxies =
128 target.requiresIproxy() ||
129 options.isSet("miranda");
130
131 if (target.generateStackMapTable()) {
132 // ignore cldc because we cannot have both stackmap formats
133 this.stackMap = StackMapFormat.JSR202;
134 } else {
135 if (target.generateCLDCStackmap()) {
136 this.stackMap = StackMapFormat.CLDC;
137 } else {
138 this.stackMap = StackMapFormat.NONE;
139 }
140 }
141
142 // by default, avoid jsr's for simple finalizers
143 int setjsrlimit = 50;
144 String jsrlimitString = options.get("jsrlimit");
145 if (jsrlimitString != null) {
146 try {
147 setjsrlimit = Integer.parseInt(jsrlimitString);
148 } catch (NumberFormatException ex) {
149 // ignore ill-formed numbers for jsrlimit
150 }
151 }
152 this.jsrlimit = setjsrlimit;
153 this.useJsrLocally = false; // reset in visitTry
154 }
155
156 /** Switches
157 */
158 private final boolean lineDebugInfo;
159 private final boolean varDebugInfo;
160 private final boolean genCrt;
161 private final boolean debugCode;
162 private final boolean allowInvokedynamic;
163
164 /** Default limit of (approximate) size of finalizer to inline.
165 * Zero means always use jsr. 100 or greater means never use
166 * jsr.
167 */
168 private final int jsrlimit;
169
170 /** True if jsr is used.
171 */
172 private boolean useJsrLocally;
173
174 /* Constant pool, reset by genClass.
175 */
176 private Pool pool = new Pool();
177
178 /** Code buffer, set by genMethod.
179 */
180 private Code code;
181
182 /** Items structure, set by genMethod.
183 */
184 private Items items;
185
186 /** Environment for symbol lookup, set by genClass
187 */
188 private Env<AttrContext> attrEnv;
189
190 /** The top level tree.
191 */
192 private JCCompilationUnit toplevel;
193
194 /** The number of code-gen errors in this class.
195 */
196 private int nerrs = 0;
197
198 /** A hash table mapping syntax trees to their ending source positions.
199 */
200 private Map<JCTree, Integer> endPositions;
201
202 /** Generate code to load an integer constant.
203 * @param n The integer to be loaded.
204 */
205 void loadIntConst(int n) {
206 items.makeImmediateItem(syms.intType, n).load();
207 }
208
209 /** The opcode that loads a zero constant of a given type code.
210 * @param tc The given type code (@see ByteCode).
211 */
212 public static int zero(int tc) {
213 switch(tc) {
214 case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
215 return iconst_0;
216 case LONGcode:
217 return lconst_0;
218 case FLOATcode:
219 return fconst_0;
220 case DOUBLEcode:
221 return dconst_0;
222 default:
223 throw new AssertionError("zero");
224 }
225 }
226
227 /** The opcode that loads a one constant of a given type code.
228 * @param tc The given type code (@see ByteCode).
229 */
230 public static int one(int tc) {
231 return zero(tc) + 1;
232 }
233
234 /** Generate code to load -1 of the given type code (either int or long).
235 * @param tc The given type code (@see ByteCode).
236 */
237 void emitMinusOne(int tc) {
238 if (tc == LONGcode) {
239 items.makeImmediateItem(syms.longType, new Long(-1)).load();
240 } else {
241 code.emitop0(iconst_m1);
242 }
243 }
244
245 /** Construct a symbol to reflect the qualifying type that should
246 * appear in the byte code as per JLS 13.1.
247 *
248 * For target >= 1.2: Clone a method with the qualifier as owner (except
249 * for those cases where we need to work around VM bugs).
250 *
251 * For target <= 1.1: If qualified variable or method is defined in a
252 * non-accessible class, clone it with the qualifier class as owner.
253 *
254 * @param sym The accessed symbol
255 * @param site The qualifier's type.
256 */
257 Symbol binaryQualifier(Symbol sym, Type site) {
258
259 if (site.tag == ARRAY) {
260 if (sym == syms.lengthVar ||
261 sym.owner != syms.arrayClass)
262 return sym;
263 // array clone can be qualified by the array type in later targets
264 Symbol qualifier = target.arrayBinaryCompatibility()
265 ? new ClassSymbol(Flags.PUBLIC, site.tsym.name,
266 site, syms.noSymbol)
267 : syms.objectType.tsym;
268 return sym.clone(qualifier);
269 }
270
271 if (sym.owner == site.tsym ||
272 (sym.flags() & (STATIC | SYNTHETIC)) == (STATIC | SYNTHETIC)) {
273 return sym;
274 }
275 if (!target.obeyBinaryCompatibility())
276 return rs.isAccessible(attrEnv, (TypeSymbol)sym.owner)
277 ? sym
278 : sym.clone(site.tsym);
279
280 if (!target.interfaceFieldsBinaryCompatibility()) {
281 if ((sym.owner.flags() & INTERFACE) != 0 && sym.kind == VAR)
282 return sym;
283 }
284
285 // leave alone methods inherited from Object
286 // JLS 13.1.
287 if (sym.owner == syms.objectType.tsym)
288 return sym;
289
290 if (!target.interfaceObjectOverridesBinaryCompatibility()) {
291 if ((sym.owner.flags() & INTERFACE) != 0 &&
292 syms.objectType.tsym.members().lookup(sym.name).scope != null)
293 return sym;
294 }
295
296 return sym.clone(site.tsym);
297 }
298
299 /** Insert a reference to given type in the constant pool,
300 * checking for an array with too many dimensions;
301 * return the reference's index.
302 * @param type The type for which a reference is inserted.
303 */
304 int makeRef(DiagnosticPosition pos, Type type) {
305 checkDimension(pos, type);
306 return pool.put(type.tag == CLASS ? (Object)type.tsym : (Object)type);
307 }
308
309 /** Check if the given type is an array with too many dimensions.
310 */
311 private void checkDimension(DiagnosticPosition pos, Type t) {
312 switch (t.tag) {
313 case METHOD:
314 checkDimension(pos, t.getReturnType());
315 for (List<Type> args = t.getParameterTypes(); args.nonEmpty(); args = args.tail)
316 checkDimension(pos, args.head);
317 break;
318 case ARRAY:
319 if (types.dimensions(t) > ClassFile.MAX_DIMENSIONS) {
320 log.error(pos, "limit.dimensions");
321 nerrs++;
322 }
323 break;
324 default:
325 break;
326 }
327 }
328
329 /** Create a tempory variable.
330 * @param type The variable's type.
331 */
332 LocalItem makeTemp(Type type) {
333 VarSymbol v = new VarSymbol(Flags.SYNTHETIC,
334 names.empty,
335 type,
336 env.enclMethod.sym);
337 code.newLocal(v);
338 return items.makeLocalItem(v);
339 }
340
341 /** Generate code to call a non-private method or constructor.
342 * @param pos Position to be used for error reporting.
343 * @param site The type of which the method is a member.
344 * @param name The method's name.
345 * @param argtypes The method's argument types.
346 * @param isStatic A flag that indicates whether we call a
347 * static or instance method.
348 */
349 void callMethod(DiagnosticPosition pos,
350 Type site, Name name, List<Type> argtypes,
351 boolean isStatic) {
352 Symbol msym = rs.
353 resolveInternalMethod(pos, attrEnv, site, name, argtypes, null);
354 if (isStatic) items.makeStaticItem(msym).invoke();
355 else items.makeMemberItem(msym, name == names.init).invoke();
356 }
357
358 /** Is the given method definition an access method
359 * resulting from a qualified super? This is signified by an odd
360 * access code.
361 */
362 private boolean isAccessSuper(JCMethodDecl enclMethod) {
363 return
364 (enclMethod.mods.flags & SYNTHETIC) != 0 &&
365 isOddAccessName(enclMethod.name);
366 }
367
368 /** Does given name start with "access$" and end in an odd digit?
369 */
370 private boolean isOddAccessName(Name name) {
371 return
372 name.startsWith(accessDollar) &&
373 (name.getByteAt(name.getByteLength() - 1) & 1) == 1;
374 }
375
376 /* ************************************************************************
377 * Non-local exits
378 *************************************************************************/
379
380 /** Generate code to invoke the finalizer associated with given
381 * environment.
382 * Any calls to finalizers are appended to the environments `cont' chain.
383 * Mark beginning of gap in catch all range for finalizer.
384 */
385 void genFinalizer(Env<GenContext> env) {
386 if (code.isAlive() && env.info.finalize != null)
387 env.info.finalize.gen();
388 }
389
390 /** Generate code to call all finalizers of structures aborted by
391 * a non-local
392 * exit. Return target environment of the non-local exit.
393 * @param target The tree representing the structure that's aborted
394 * @param env The environment current at the non-local exit.
395 */
396 Env<GenContext> unwind(JCTree target, Env<GenContext> env) {
397 Env<GenContext> env1 = env;
398 while (true) {
399 genFinalizer(env1);
400 if (env1.tree == target) break;
401 env1 = env1.next;
402 }
403 return env1;
404 }
405
406 /** Mark end of gap in catch-all range for finalizer.
407 * @param env the environment which might contain the finalizer
408 * (if it does, env.info.gaps != null).
409 */
410 void endFinalizerGap(Env<GenContext> env) {
411 if (env.info.gaps != null && env.info.gaps.length() % 2 == 1)
412 env.info.gaps.append(code.curPc());
413 }
414
415 /** Mark end of all gaps in catch-all ranges for finalizers of environments
416 * lying between, and including to two environments.
417 * @param from the most deeply nested environment to mark
418 * @param to the least deeply nested environment to mark
419 */
420 void endFinalizerGaps(Env<GenContext> from, Env<GenContext> to) {
421 Env<GenContext> last = null;
422 while (last != to) {
423 endFinalizerGap(from);
424 last = from;
425 from = from.next;
426 }
427 }
428
429 /** Do any of the structures aborted by a non-local exit have
430 * finalizers that require an empty stack?
431 * @param target The tree representing the structure that's aborted
432 * @param env The environment current at the non-local exit.
433 */
434 boolean hasFinally(JCTree target, Env<GenContext> env) {
435 while (env.tree != target) {
436 if (env.tree.getTag() == JCTree.TRY && env.info.finalize.hasFinalizer())
437 return true;
438 env = env.next;
439 }
440 return false;
441 }
442
443 /* ************************************************************************
444 * Normalizing class-members.
445 *************************************************************************/
446
447 /** Distribute member initializer code into constructors and <clinit>
448 * method.
449 * @param defs The list of class member declarations.
450 * @param c The enclosing class.
451 */
452 List<JCTree> normalizeDefs(List<JCTree> defs, ClassSymbol c) {
453 ListBuffer<JCStatement> initCode = new ListBuffer<JCStatement>();
454 ListBuffer<JCStatement> clinitCode = new ListBuffer<JCStatement>();
455 ListBuffer<JCTree> methodDefs = new ListBuffer<JCTree>();
456 // Sort definitions into three listbuffers:
457 // - initCode for instance initializers
458 // - clinitCode for class initializers
459 // - methodDefs for method definitions
460 for (List<JCTree> l = defs; l.nonEmpty(); l = l.tail) {
461 JCTree def = l.head;
462 switch (def.getTag()) {
463 case JCTree.BLOCK:
464 JCBlock block = (JCBlock)def;
465 if ((block.flags & STATIC) != 0)
466 clinitCode.append(block);
467 else
468 initCode.append(block);
469 break;
470 case JCTree.METHODDEF:
471 methodDefs.append(def);
472 break;
473 case JCTree.VARDEF:
474 JCVariableDecl vdef = (JCVariableDecl) def;
475 VarSymbol sym = vdef.sym;
476 checkDimension(vdef.pos(), sym.type);
477 if (vdef.init != null) {
478 if ((sym.flags() & STATIC) == 0) {
479 // Always initialize instance variables.
480 JCStatement init = make.at(vdef.pos()).
481 Assignment(sym, vdef.init);
482 initCode.append(init);
483 if (endPositions != null) {
484 Integer endPos = endPositions.remove(vdef);
485 if (endPos != null) endPositions.put(init, endPos);
486 }
487 } else if (sym.getConstValue() == null) {
488 // Initialize class (static) variables only if
489 // they are not compile-time constants.
490 JCStatement init = make.at(vdef.pos).
491 Assignment(sym, vdef.init);
492 clinitCode.append(init);
493 if (endPositions != null) {
494 Integer endPos = endPositions.remove(vdef);
495 if (endPos != null) endPositions.put(init, endPos);
496 }
497 } else {
498 checkStringConstant(vdef.init.pos(), sym.getConstValue());
499 }
500 }
501 break;
502 default:
503 Assert.error();
504 }
505 }
506 // Insert any instance initializers into all constructors.
507 if (initCode.length() != 0) {
508 List<JCStatement> inits = initCode.toList();
509 for (JCTree t : methodDefs) {
510 normalizeMethod((JCMethodDecl)t, inits);
511 }
512 }
513 // If there are class initializers, create a <clinit> method
514 // that contains them as its body.
515 if (clinitCode.length() != 0) {
516 MethodSymbol clinit = new MethodSymbol(
517 STATIC, names.clinit,
518 new MethodType(
519 List.<Type>nil(), syms.voidType,
520 List.<Type>nil(), syms.methodClass),
521 c);
522 c.members().enter(clinit);
523 List<JCStatement> clinitStats = clinitCode.toList();
524 JCBlock block = make.at(clinitStats.head.pos()).Block(0, clinitStats);
525 block.endpos = TreeInfo.endPos(clinitStats.last());
526 methodDefs.append(make.MethodDef(clinit, block));
527 }
528 // Return all method definitions.
529 return methodDefs.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 */
550 void normalizeMethod(JCMethodDecl md, List<JCStatement> initCode) {
551 if (md.name == names.init && TreeInfo.isInitialConstructor(md)) {
552 // We are seeing a constructor that does not call another
553 // constructor of the same class.
554 List<JCStatement> stats = md.body.stats;
555 ListBuffer<JCStatement> newstats = new ListBuffer<JCStatement>();
556
557 if (stats.nonEmpty()) {
558 // Copy initializers of synthetic variables generated in
559 // the translation of inner classes.
560 while (TreeInfo.isSyntheticInit(stats.head)) {
561 newstats.append(stats.head);
562 stats = stats.tail;
563 }
564 // Copy superclass constructor call
565 newstats.append(stats.head);
566 stats = stats.tail;
567 // Copy remaining synthetic initializers.
568 while (stats.nonEmpty() &&
569 TreeInfo.isSyntheticInit(stats.head)) {
570 newstats.append(stats.head);
571 stats = stats.tail;
572 }
573 // Now insert the initializer code.
574 newstats.appendList(initCode);
575 // And copy all remaining statements.
576 while (stats.nonEmpty()) {
577 newstats.append(stats.head);
578 stats = stats.tail;
579 }
580 }
581 md.body.stats = newstats.toList();
582 if (md.body.endpos == Position.NOPOS)
583 md.body.endpos = TreeInfo.endPos(md.body.stats.last());
584 }
585 }
586
587 /* ********************************************************************
588 * Adding miranda methods
589 *********************************************************************/
590
591 /** Add abstract methods for all methods defined in one of
592 * the interfaces of a given class,
593 * provided they are not already implemented in the class.
594 *
595 * @param c The class whose interfaces are searched for methods
596 * for which Miranda methods should be added.
597 */
598 void implementInterfaceMethods(ClassSymbol c) {
599 implementInterfaceMethods(c, c);
600 }
601
602 /** Add abstract methods for all methods defined in one of
603 * the interfaces of a given class,
604 * provided they are not already implemented in the class.
605 *
606 * @param c The class whose interfaces are searched for methods
607 * for which Miranda methods should be added.
608 * @param site The class in which a definition may be needed.
609 */
610 void implementInterfaceMethods(ClassSymbol c, ClassSymbol site) {
611 for (List<Type> l = types.interfaces(c.type); l.nonEmpty(); l = l.tail) {
612 ClassSymbol i = (ClassSymbol)l.head.tsym;
613 for (Scope.Entry e = i.members().elems;
614 e != null;
615 e = e.sibling)
616 {
617 if (e.sym.kind == MTH && (e.sym.flags() & STATIC) == 0)
618 {
619 MethodSymbol absMeth = (MethodSymbol)e.sym;
620 MethodSymbol implMeth = absMeth.binaryImplementation(site, types);
621 if (implMeth == null)
622 addAbstractMethod(site, absMeth);
623 else if ((implMeth.flags() & IPROXY) != 0)
624 adjustAbstractMethod(site, implMeth, absMeth);
625 }
626 }
627 implementInterfaceMethods(i, site);
628 }
629 }
630
631 /** Add an abstract methods to a class
632 * which implicitly implements a method defined in some interface
633 * implemented by the class. These methods are called "Miranda methods".
634 * Enter the newly created method into its enclosing class scope.
635 * Note that it is not entered into the class tree, as the emitter
636 * doesn't need to see it there to emit an abstract method.
637 *
638 * @param c The class to which the Miranda method is added.
639 * @param m The interface method symbol for which a Miranda method
640 * is added.
641 */
642 private void addAbstractMethod(ClassSymbol c,
643 MethodSymbol m) {
644 MethodSymbol absMeth = new MethodSymbol(
645 m.flags() | IPROXY | SYNTHETIC, m.name,
646 m.type, // was c.type.memberType(m), but now only !generics supported
647 c);
648 c.members().enter(absMeth); // add to symbol table
649 }
650
651 private void adjustAbstractMethod(ClassSymbol c,
652 MethodSymbol pm,
653 MethodSymbol im) {
654 MethodType pmt = (MethodType)pm.type;
655 Type imt = types.memberType(c.type, im);
656 pmt.thrown = chk.intersect(pmt.getThrownTypes(), imt.getThrownTypes());
657 }
658
659 /* ************************************************************************
660 * Traversal methods
661 *************************************************************************/
662
663 /** Visitor argument: The current environment.
664 */
665 Env<GenContext> env;
666
667 /** Visitor argument: The expected type (prototype).
668 */
669 Type pt;
670
671 /** Visitor result: The item representing the computed value.
672 */
673 Item result;
674
675 /** Visitor method: generate code for a definition, catching and reporting
676 * any completion failures.
677 * @param tree The definition to be visited.
678 * @param env The environment current at the definition.
679 */
680 public void genDef(JCTree tree, Env<GenContext> env) {
681 Env<GenContext> prevEnv = this.env;
682 try {
683 this.env = env;
684 tree.accept(this);
685 } catch (CompletionFailure ex) {
686 chk.completionError(tree.pos(), ex);
687 } finally {
688 this.env = prevEnv;
689 }
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 #genStat(Tree, Env)
697 *
698 * @param tree The tree to be visited.
699 * @param env The environment to use.
700 * @param crtFlags The CharacterRangeTable flags
701 * indicating type of the entry.
702 */
703 public void genStat(JCTree tree, Env<GenContext> env, int crtFlags) {
704 if (!genCrt) {
705 genStat(tree, env);
706 return;
707 }
708 int startpc = code.curPc();
709 genStat(tree, env);
710 if (tree.getTag() == JCTree.BLOCK) crtFlags |= CRT_BLOCK;
711 code.crt.put(tree, crtFlags, startpc, code.curPc());
712 }
713
714 /** Derived visitor method: generate code for a statement.
715 */
716 public void genStat(JCTree tree, Env<GenContext> env) {
717 if (code.isAlive()) {
718 code.statBegin(tree.pos);
719 genDef(tree, env);
720 } else if (env.info.isSwitch && tree.getTag() == JCTree.VARDEF) {
721 // variables whose declarations are in a switch
722 // can be used even if the decl is unreachable.
723 code.newLocal(((JCVariableDecl) tree).sym);
724 }
725 }
726
727 /** Derived visitor method: check whether CharacterRangeTable
728 * should be emitted, if so, put a new entry into CRTable
729 * and call method to generate bytecode.
730 * If not, just call method to generate bytecode.
731 * @see #genStats(List, Env)
732 *
733 * @param trees The list of trees to be visited.
734 * @param env The environment to use.
735 * @param crtFlags The CharacterRangeTable flags
736 * indicating type of the entry.
737 */
738 public void genStats(List<JCStatement> trees, Env<GenContext> env, int crtFlags) {
739 if (!genCrt) {
740 genStats(trees, env);
741 return;
742 }
743 if (trees.length() == 1) { // mark one statement with the flags
744 genStat(trees.head, env, crtFlags | CRT_STATEMENT);
745 } else {
746 int startpc = code.curPc();
747 genStats(trees, env);
748 code.crt.put(trees, crtFlags, startpc, code.curPc());
749 }
750 }
751
752 /** Derived visitor method: generate code for a list of statements.
753 */
754 public void genStats(List<? extends JCTree> trees, Env<GenContext> env) {
755 for (List<? extends JCTree> l = trees; l.nonEmpty(); l = l.tail)
756 genStat(l.head, env, CRT_STATEMENT);
757 }
758
759 /** Derived visitor method: check whether CharacterRangeTable
760 * should be emitted, if so, put a new entry into CRTable
761 * and call method to generate bytecode.
762 * If not, just call method to generate bytecode.
763 * @see #genCond(Tree,boolean)
764 *
765 * @param tree The tree to be visited.
766 * @param crtFlags The CharacterRangeTable flags
767 * indicating type of the entry.
768 */
769 public CondItem genCond(JCTree tree, int crtFlags) {
770 if (!genCrt) return genCond(tree, false);
771 int startpc = code.curPc();
772 CondItem item = genCond(tree, (crtFlags & CRT_FLOW_CONTROLLER) != 0);
773 code.crt.put(tree, crtFlags, startpc, code.curPc());
774 return item;
775 }
776
777 /** Derived visitor method: generate code for a boolean
778 * expression in a control-flow context.
779 * @param _tree The expression to be visited.
780 * @param markBranches The flag to indicate that the condition is
781 * a flow controller so produced conditions
782 * should contain a proper tree to generate
783 * CharacterRangeTable branches for them.
784 */
785 public CondItem genCond(JCTree _tree, boolean markBranches) {
786 JCTree inner_tree = TreeInfo.skipParens(_tree);
787 if (inner_tree.getTag() == JCTree.CONDEXPR) {
788 JCConditional tree = (JCConditional)inner_tree;
789 CondItem cond = genCond(tree.cond, CRT_FLOW_CONTROLLER);
790 if (cond.isTrue()) {
791 code.resolve(cond.trueJumps);
792 CondItem result = genCond(tree.truepart, CRT_FLOW_TARGET);
793 if (markBranches) result.tree = tree.truepart;
794 return result;
795 }
796 if (cond.isFalse()) {
797 code.resolve(cond.falseJumps);
798 CondItem result = genCond(tree.falsepart, CRT_FLOW_TARGET);
799 if (markBranches) result.tree = tree.falsepart;
800 return result;
801 }
802 Chain secondJumps = cond.jumpFalse();
803 code.resolve(cond.trueJumps);
804 CondItem first = genCond(tree.truepart, CRT_FLOW_TARGET);
805 if (markBranches) first.tree = tree.truepart;
806 Chain falseJumps = first.jumpFalse();
807 code.resolve(first.trueJumps);
808 Chain trueJumps = code.branch(goto_);
809 code.resolve(secondJumps);
810 CondItem second = genCond(tree.falsepart, CRT_FLOW_TARGET);
811 CondItem result = items.makeCondItem(second.opcode,
812 Code.mergeChains(trueJumps, second.trueJumps),
813 Code.mergeChains(falseJumps, second.falseJumps));
814 if (markBranches) result.tree = tree.falsepart;
815 return result;
816 } else {
817 CondItem result = genExpr(_tree, syms.booleanType).mkCond();
818 if (markBranches) result.tree = _tree;
819 return result;
820 }
821 }
822
823 /** Visitor method: generate code for an expression, catching and reporting
824 * any completion failures.
825 * @param tree The expression to be visited.
826 * @param pt The expression's expected type (proto-type).
827 */
828 public Item genExpr(JCTree tree, Type pt) {
829 Type prevPt = this.pt;
830 try {
831 if (tree.type.constValue() != null) {
832 // Short circuit any expressions which are constants
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
880 // The expected type of every return statement in this method
881 // is the method's return type.
882 this.pt = tree.sym.erasure(types).getReturnType();
883
884 checkDimension(tree.pos(), tree.sym.erasure(types));
885 genMethod(tree, localEnv, false);
886 }
887 //where
888 /** Generate code for a method.
889 * @param tree The tree representing the method definition.
890 * @param env The environment current for the method body.
891 * @param fatcode A flag that indicates whether all jumps are
892 * within 32K. We first invoke this method under
893 * the assumption that fatcode == false, i.e. all
894 * jumps are within 32K. If this fails, fatcode
895 * is set to true and we try again.
896 */
897 void genMethod(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
898 MethodSymbol meth = tree.sym;
899 // System.err.println("Generating " + meth + " in " + meth.owner); //DEBUG
900 if (Code.width(types.erasure(env.enclMethod.sym.type).getParameterTypes()) +
901 (((tree.mods.flags & STATIC) == 0 || meth.isConstructor()) ? 1 : 0) >
902 ClassFile.MAX_PARAMETERS) {
903 log.error(tree.pos(), "limit.parameters");
904 nerrs++;
905 }
906
907 else if (tree.body != null) {
908 // Create a new code structure and initialize it.
909 int startpcCrt = initCode(tree, env, fatcode);
910
911 try {
912 genStat(tree.body, env);
913 } catch (CodeSizeOverflow e) {
914 // Failed due to code limit, try again with jsr/ret
915 startpcCrt = initCode(tree, env, fatcode);
916 genStat(tree.body, env);
917 }
918
919 if (code.state.stacksize != 0) {
920 log.error(tree.body.pos(), "stack.sim.error", tree);
921 throw new AssertionError();
922 }
923
924 // If last statement could complete normally, insert a
925 // return at the end.
926 if (code.isAlive()) {
927 code.statBegin(TreeInfo.endPos(tree.body));
928 if (env.enclMethod == null ||
929 env.enclMethod.sym.type.getReturnType().tag == VOID) {
930 code.emitop0(return_);
931 } else {
932 // sometime dead code seems alive (4415991);
933 // generate a small loop instead
934 int startpc = code.entryPoint();
935 CondItem c = items.makeCondItem(goto_);
936 code.resolve(c.jumpTrue(), startpc);
937 }
938 }
939 if (genCrt)
940 code.crt.put(tree.body,
941 CRT_BLOCK,
942 startpcCrt,
943 code.curPc());
944
945 code.endScopes(0);
946
947 // If we exceeded limits, panic
948 if (code.checkLimits(tree.pos(), log)) {
949 nerrs++;
950 return;
951 }
952
953 // If we generated short code but got a long jump, do it again
954 // with fatCode = true.
955 if (!fatcode && code.fatcode) genMethod(tree, env, true);
956
957 // Clean up
958 if(stackMap == StackMapFormat.JSR202) {
959 code.lastFrame = null;
960 code.frameBeforeLast = null;
961 }
962
963 //compress exception table
964 code.compressCatchTable();
965 }
966 }
967
968 private int initCode(JCMethodDecl tree, Env<GenContext> env, boolean fatcode) {
969 MethodSymbol meth = tree.sym;
970
971 // Create a new code structure.
972 meth.code = code = new Code(meth,
973 fatcode,
974 lineDebugInfo ? toplevel.lineMap : null,
975 varDebugInfo,
976 stackMap,
977 debugCode,
978 genCrt ? new CRTable(tree, env.toplevel.endPositions)
979 : null,
980 syms,
981 types,
982 pool);
983 items = new Items(pool, code, syms, types);
984 if (code.debugCode)
985 System.err.println(meth + " for body " + tree);
986
987 // If method is not static, create a new local variable address
988 // for `this'.
989 if ((tree.mods.flags & STATIC) == 0) {
990 Type selfType = meth.owner.type;
991 if (meth.isConstructor() && selfType != syms.objectType)
992 selfType = UninitializedType.uninitializedThis(selfType);
993 code.setDefined(
994 code.newLocal(
995 new VarSymbol(FINAL, names._this, selfType, meth.owner)));
996 }
997
998 // Mark all parameters as defined from the beginning of
999 // the method.
1000 for (List<JCVariableDecl> l = tree.params; l.nonEmpty(); l = l.tail) {
1001 checkDimension(l.head.pos(), l.head.sym.type);
1002 code.setDefined(code.newLocal(l.head.sym));
1003 }
1004
1005 // Get ready to generate code for method body.
1006 int startpcCrt = genCrt ? code.curPc() : 0;
1007 code.entryPoint();
1008
1009 // Suppress initial stackmap
1010 code.pendingStackMap = false;
1011
1012 return startpcCrt;
1013 }
1014
1015 public void visitVarDef(JCVariableDecl tree) {
1016 VarSymbol v = tree.sym;
1017 code.newLocal(v);
1018 if (tree.init != null) {
1019 checkStringConstant(tree.init.pos(), v.getConstValue());
1020 if (v.getConstValue() == null || varDebugInfo) {
1021 genExpr(tree.init, v.erasure(types)).load();
1022 items.makeLocalItem(v).store();
1023 }
1024 }
1025 checkDimension(tree.pos(), v.type);
1026 }
1027
1028 public void visitSkip(JCSkip tree) {
1029 }
1030
1031 public void visitBlock(JCBlock tree) {
1032 int limit = code.nextreg;
1033 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1034 genStats(tree.stats, localEnv);
1035 // End the scope of all block-local variables in variable info.
1036 if (env.tree.getTag() != JCTree.METHODDEF) {
1037 code.statBegin(tree.endpos);
1038 code.endScopes(limit);
1039 code.pendingStatPos = Position.NOPOS;
1040 }
1041 }
1042
1043 public void visitDoLoop(JCDoWhileLoop tree) {
1044 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), false);
1045 }
1046
1047 public void visitWhileLoop(JCWhileLoop tree) {
1048 genLoop(tree, tree.body, tree.cond, List.<JCExpressionStatement>nil(), true);
1049 }
1050
1051 public void visitForLoop(JCForLoop tree) {
1052 int limit = code.nextreg;
1053 genStats(tree.init, env);
1054 genLoop(tree, tree.body, tree.cond, tree.step, true);
1055 code.endScopes(limit);
1056 }
1057 //where
1058 /** Generate code for a loop.
1059 * @param loop The tree representing the loop.
1060 * @param body The loop's body.
1061 * @param cond The loop's controling condition.
1062 * @param step "Step" statements to be inserted at end of
1063 * each iteration.
1064 * @param testFirst True if the loop test belongs before the body.
1065 */
1066 private void genLoop(JCStatement loop,
1067 JCStatement body,
1068 JCExpression cond,
1069 List<JCExpressionStatement> step,
1070 boolean testFirst) {
1071 Env<GenContext> loopEnv = env.dup(loop, new GenContext());
1072 int startpc = code.entryPoint();
1073 if (testFirst) {
1074 CondItem c;
1075 if (cond != null) {
1076 code.statBegin(cond.pos);
1077 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1078 } else {
1079 c = items.makeCondItem(goto_);
1080 }
1081 Chain loopDone = c.jumpFalse();
1082 code.resolve(c.trueJumps);
1083 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1084 code.resolve(loopEnv.info.cont);
1085 genStats(step, loopEnv);
1086 code.resolve(code.branch(goto_), startpc);
1087 code.resolve(loopDone);
1088 } else {
1089 genStat(body, loopEnv, CRT_STATEMENT | CRT_FLOW_TARGET);
1090 code.resolve(loopEnv.info.cont);
1091 genStats(step, loopEnv);
1092 CondItem c;
1093 if (cond != null) {
1094 code.statBegin(cond.pos);
1095 c = genCond(TreeInfo.skipParens(cond), CRT_FLOW_CONTROLLER);
1096 } else {
1097 c = items.makeCondItem(goto_);
1098 }
1099 code.resolve(c.jumpTrue(), startpc);
1100 code.resolve(c.falseJumps);
1101 }
1102 code.resolve(loopEnv.info.exit);
1103 }
1104
1105 public void visitForeachLoop(JCEnhancedForLoop tree) {
1106 throw new AssertionError(); // should have been removed by Lower.
1107 }
1108
1109 public void visitLabelled(JCLabeledStatement tree) {
1110 Env<GenContext> localEnv = env.dup(tree, new GenContext());
1111 genStat(tree.body, localEnv, CRT_STATEMENT);
1112 code.resolve(localEnv.info.exit);
1113 }
1114
1115 public void visitSwitch(JCSwitch tree) {
1116 int limit = code.nextreg;
1117 Assert.check(tree.selector.type.tag != CLASS);
1118 int startpcCrt = genCrt ? code.curPc() : 0;
1119 Item sel = genExpr(tree.selector, syms.intType);
1120 List<JCCase> cases = tree.cases;
1121 if (cases.isEmpty()) {
1122 // We are seeing: switch <sel> {}
1123 sel.load().drop();
1124 if (genCrt)
1125 code.crt.put(TreeInfo.skipParens(tree.selector),
1126 CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
1127 } else {
1128 // We are seeing a nonempty switch.
1129 sel.load();
1130 if (genCrt)
1131 code.crt.put(TreeInfo.skipParens(tree.selector),
1132 CRT_FLOW_CONTROLLER, startpcCrt, code.curPc());
1133 Env<GenContext> switchEnv = env.dup(tree, new GenContext());
1134 switchEnv.info.isSwitch = true;
1135
1136 // Compute number of labels and minimum and maximum label values.
1137 // For each case, store its label in an array.
1138 int lo = Integer.MAX_VALUE; // minimum label.
1139 int hi = Integer.MIN_VALUE; // maximum label.
1140 int nlabels = 0; // number of labels.
1141
1142 int[] labels = new int[cases.length()]; // the label array.
1143 int defaultIndex = -1; // the index of the default clause.
1144
1145 List<JCCase> l = cases;
1146 for (int i = 0; i < labels.length; i++) {
1147 if (l.head.pat != null) {
1148 int val = ((Number)l.head.pat.type.constValue()).intValue();
1149 labels[i] = val;
1150 if (val < lo) lo = val;
1151 if (hi < val) hi = val;
1152 nlabels++;
1153 } else {
1154 Assert.check(defaultIndex == -1);
1155 defaultIndex = i;
1156 }
1157 l = l.tail;
1158 }
1159
1160 // Determine whether to issue a tableswitch or a lookupswitch
1161 // instruction.
1162 long table_space_cost = 4 + ((long) hi - lo + 1); // words
1163 long table_time_cost = 3; // comparisons
1164 long lookup_space_cost = 3 + 2 * (long) nlabels;
1165 long lookup_time_cost = nlabels;
1166 int opcode =
1167 nlabels > 0 &&
1168 table_space_cost + 3 * table_time_cost <=
1169 lookup_space_cost + 3 * lookup_time_cost
1170 ?
1171 tableswitch : lookupswitch;
1172
1173 int startpc = code.curPc(); // the position of the selector operation
1174 code.emitop0(opcode);
1175 code.align(4);
1176 int tableBase = code.curPc(); // the start of the jump table
1177 int[] offsets = null; // a table of offsets for a lookupswitch
1178 code.emit4(-1); // leave space for default offset
1179 if (opcode == tableswitch) {
1180 code.emit4(lo); // minimum label
1181 code.emit4(hi); // maximum label
1182 for (long i = lo; i <= hi; i++) { // leave space for jump table
1183 code.emit4(-1);
1184 }
1185 } else {
1186 code.emit4(nlabels); // number of labels
1187 for (int i = 0; i < nlabels; i++) {
1188 code.emit4(-1); code.emit4(-1); // leave space for lookup table
1189 }
1190 offsets = new int[labels.length];
1191 }
1192 Code.State stateSwitch = code.state.dup();
1193 code.markDead();
1194
1195 // For each case do:
1196 l = cases;
1197 for (int i = 0; i < labels.length; i++) {
1198 JCCase c = l.head;
1199 l = l.tail;
1200
1201 int pc = code.entryPoint(stateSwitch);
1202 // Insert offset directly into code or else into the
1203 // offsets table.
1204 if (i != defaultIndex) {
1205 if (opcode == tableswitch) {
1206 code.put4(
1207 tableBase + 4 * (labels[i] - lo + 3),
1208 pc - startpc);
1209 } else {
1210 offsets[i] = pc - startpc;
1211 }
1212 } else {
1213 code.put4(tableBase, pc - startpc);
1214 }
1215
1216 // Generate code for the statements in this case.
1217 genStats(c.stats, switchEnv, CRT_FLOW_TARGET);
1218 }
1219
1220 // Resolve all breaks.
1221 code.resolve(switchEnv.info.exit);
1222
1223 // If we have not set the default offset, we do so now.
1224 if (code.get4(tableBase) == -1) {
1225 code.put4(tableBase, code.entryPoint(stateSwitch) - startpc);
1226 }
1227
1228 if (opcode == tableswitch) {
1229 // Let any unfilled slots point to the default case.
1230 int defaultOffset = code.get4(tableBase);
1231 for (long i = lo; i <= hi; i++) {
1232 int t = (int)(tableBase + 4 * (i - lo + 3));
1233 if (code.get4(t) == -1)
1234 code.put4(t, defaultOffset);
1235 }
1236 } else {
1237 // Sort non-default offsets and copy into lookup table.
1238 if (defaultIndex >= 0)
1239 for (int i = defaultIndex; i < labels.length - 1; i++) {
1240 labels[i] = labels[i+1];
1241 offsets[i] = offsets[i+1];
1242 }
1243 if (nlabels > 0)
1244 qsort2(labels, offsets, 0, nlabels - 1);
1245 for (int i = 0; i < nlabels; i++) {
1246 int caseidx = tableBase + 8 * (i + 1);
1247 code.put4(caseidx, labels[i]);
1248 code.put4(caseidx + 4, offsets[i]);
1249 }
1250 }
1251 }
1252 code.endScopes(limit);
1253 }
1254 //where
1255 /** Sort (int) arrays of keys and values
1256 */
1257 static void qsort2(int[] keys, int[] values, int lo, int hi) {
1258 int i = lo;
1259 int j = hi;
1260 int pivot = keys[(i+j)/2];
1261 do {
1262 while (keys[i] < pivot) i++;
1263 while (pivot < keys[j]) j--;
1264 if (i <= j) {
1265 int temp1 = keys[i];
1266 keys[i] = keys[j];
1267 keys[j] = temp1;
1268 int temp2 = values[i];
1269 values[i] = values[j];
1270 values[j] = temp2;
1271 i++;
1272 j--;
1273 }
1274 } while (i <= j);
1275 if (lo < j) qsort2(keys, values, lo, j);
1276 if (i < hi) qsort2(keys, values, i, hi);
1277 }
1278
1279 public void visitSynchronized(JCSynchronized tree) {
1280 int limit = code.nextreg;
1281 // Generate code to evaluate lock and save in temporary variable.
1282 final LocalItem lockVar = makeTemp(syms.objectType);
1283 genExpr(tree.lock, tree.lock.type).load().duplicate();
1284 lockVar.store();
1285
1286 // Generate code to enter monitor.
1287 code.emitop0(monitorenter);
1288 code.state.lock(lockVar.reg);
1289
1290 // Generate code for a try statement with given body, no catch clauses
1291 // in a new environment with the "exit-monitor" operation as finalizer.
1292 final Env<GenContext> syncEnv = env.dup(tree, new GenContext());
1293 syncEnv.info.finalize = new GenFinalizer() {
1294 void gen() {
1295 genLast();
1296 Assert.check(syncEnv.info.gaps.length() % 2 == 0);
1297 syncEnv.info.gaps.append(code.curPc());
1298 }
1299 void genLast() {
1300 if (code.isAlive()) {
1301 lockVar.load();
1302 code.emitop0(monitorexit);
1303 code.state.unlock(lockVar.reg);
1304 }
1305 }
1306 };
1307 syncEnv.info.gaps = new ListBuffer<Integer>();
1308 genTry(tree.body, List.<JCCatch>nil(), syncEnv);
1309 code.endScopes(limit);
1310 }
1311
1312 public void visitTry(final JCTry tree) {
1313 // Generate code for a try statement with given body and catch clauses,
1314 // in a new environment which calls the finally block if there is one.
1315 final Env<GenContext> tryEnv = env.dup(tree, new GenContext());
1316 final Env<GenContext> oldEnv = env;
1317 if (!useJsrLocally) {
1318 useJsrLocally =
1319 (stackMap == StackMapFormat.NONE) &&
1320 (jsrlimit <= 0 ||
1321 jsrlimit < 100 &&
1322 estimateCodeComplexity(tree.finalizer)>jsrlimit);
1323 }
1324 tryEnv.info.finalize = new GenFinalizer() {
1325 void gen() {
1326 if (useJsrLocally) {
1327 if (tree.finalizer != null) {
1328 Code.State jsrState = code.state.dup();
1329 jsrState.push(Code.jsrReturnValue);
1330 tryEnv.info.cont =
1331 new Chain(code.emitJump(jsr),
1332 tryEnv.info.cont,
1333 jsrState);
1334 }
1335 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1336 tryEnv.info.gaps.append(code.curPc());
1337 } else {
1338 Assert.check(tryEnv.info.gaps.length() % 2 == 0);
1339 tryEnv.info.gaps.append(code.curPc());
1340 genLast();
1341 }
1342 }
1343 void genLast() {
1344 if (tree.finalizer != null)
1345 genStat(tree.finalizer, oldEnv, CRT_BLOCK);
1346 }
1347 boolean hasFinalizer() {
1348 return tree.finalizer != null;
1349 }
1350 };
1351 tryEnv.info.gaps = new ListBuffer<Integer>();
1352 genTry(tree.body, tree.catchers, tryEnv);
1353 }
1354 //where
1355 /** Generate code for a try or synchronized statement
1356 * @param body The body of the try or synchronized statement.
1357 * @param catchers The lis of catch clauses.
1358 * @param env the environment current for the body.
1359 */
1360 void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
1361 int limit = code.nextreg;
1362 int startpc = code.curPc();
1363 Code.State stateTry = code.state.dup();
1364 genStat(body, env, CRT_BLOCK);
1365 int endpc = code.curPc();
1366 boolean hasFinalizer =
1367 env.info.finalize != null &&
1368 env.info.finalize.hasFinalizer();
1369 List<Integer> gaps = env.info.gaps.toList();
1370 code.statBegin(TreeInfo.endPos(body));
1371 genFinalizer(env);
1372 code.statBegin(TreeInfo.endPos(env.tree));
1373 Chain exitChain = code.branch(goto_);
1374 endFinalizerGap(env);
1375 if (startpc != endpc) for (List<JCCatch> l = catchers; l.nonEmpty(); l = l.tail) {
1376 // start off with exception on stack
1377 code.entryPoint(stateTry, l.head.param.sym.type);
1378 genCatch(l.head, env, startpc, endpc, gaps);
1379 genFinalizer(env);
1380 if (hasFinalizer || l.tail.nonEmpty()) {
1381 code.statBegin(TreeInfo.endPos(env.tree));
1382 exitChain = Code.mergeChains(exitChain,
1383 code.branch(goto_));
1384 }
1385 endFinalizerGap(env);
1386 }
1387 if (hasFinalizer) {
1388 // Create a new register segement to avoid allocating
1389 // the same variables in finalizers and other statements.
1390 code.newRegSegment();
1391
1392 // Add a catch-all clause.
1393
1394 // start off with exception on stack
1395 int catchallpc = code.entryPoint(stateTry, syms.throwableType);
1396
1397 // Register all exception ranges for catch all clause.
1398 // The range of the catch all clause is from the beginning
1399 // of the try or synchronized block until the present
1400 // code pointer excluding all gaps in the current
1401 // environment's GenContext.
1402 int startseg = startpc;
1403 while (env.info.gaps.nonEmpty()) {
1404 int endseg = env.info.gaps.next().intValue();
1405 registerCatch(body.pos(), startseg, endseg,
1406 catchallpc, 0);
1407 startseg = env.info.gaps.next().intValue();
1408 }
1409 code.statBegin(TreeInfo.finalizerPos(env.tree));
1410 code.markStatBegin();
1411
1412 Item excVar = makeTemp(syms.throwableType);
1413 excVar.store();
1414 genFinalizer(env);
1415 excVar.load();
1416 registerCatch(body.pos(), startseg,
1417 env.info.gaps.next().intValue(),
1418 catchallpc, 0);
1419 code.emitop0(athrow);
1420 code.markDead();
1421
1422 // If there are jsr's to this finalizer, ...
1423 if (env.info.cont != null) {
1424 // Resolve all jsr's.
1425 code.resolve(env.info.cont);
1426
1427 // Mark statement line number
1428 code.statBegin(TreeInfo.finalizerPos(env.tree));
1429 code.markStatBegin();
1430
1431 // Save return address.
1432 LocalItem retVar = makeTemp(syms.throwableType);
1433 retVar.store();
1434
1435 // Generate finalizer code.
1436 env.info.finalize.genLast();
1437
1438 // Return.
1439 code.emitop1w(ret, retVar.reg);
1440 code.markDead();
1441 }
1442 }
1443 // Resolve all breaks.
1444 code.resolve(exitChain);
1445
1446 code.endScopes(limit);
1447 }
1448
1449 /** Generate code for a catch clause.
1450 * @param tree The catch clause.
1451 * @param env The environment current in the enclosing try.
1452 * @param startpc Start pc of try-block.
1453 * @param endpc End pc of try-block.
1454 */
1455 void genCatch(JCCatch tree,
1456 Env<GenContext> env,
1457 int startpc, int endpc,
1458 List<Integer> gaps) {
1459 if (startpc != endpc) {
1460 List<JCExpression> subClauses = TreeInfo.isMultiCatch(tree) ?
1461 ((JCTypeUnion)tree.param.vartype).alternatives :
1462 List.of(tree.param.vartype);
1463 while (gaps.nonEmpty()) {
1464 for (JCExpression subCatch : subClauses) {
1465 int catchType = makeRef(tree.pos(), subCatch.type);
1466 int end = gaps.head.intValue();
1467 registerCatch(tree.pos(),
1468 startpc, end, code.curPc(),
1469 catchType);
1470 }
1471 gaps = gaps.tail;
1472 startpc = gaps.head.intValue();
1473 gaps = gaps.tail;
1474 }
1475 if (startpc < endpc) {
1476 for (JCExpression subCatch : subClauses) {
1477 int catchType = makeRef(tree.pos(), subCatch.type);
1478 registerCatch(tree.pos(),
1479 startpc, endpc, code.curPc(),
1480 catchType);
1481 }
1482 }
1483 VarSymbol exparam = tree.param.sym;
1484 code.statBegin(tree.pos);
1485 code.markStatBegin();
1486 int limit = code.nextreg;
1487 int exlocal = code.newLocal(exparam);
1488 items.makeLocalItem(exparam).store();
1489 code.statBegin(TreeInfo.firstStatPos(tree.body));
1490 genStat(tree.body, env, CRT_BLOCK);
1491 code.endScopes(limit);
1492 code.statBegin(TreeInfo.endPos(tree.body));
1493 }
1494 }
1495
1496 /** Register a catch clause in the "Exceptions" code-attribute.
1497 */
1498 void registerCatch(DiagnosticPosition pos,
1499 int startpc, int endpc,
1500 int handler_pc, int catch_type) {
1501 char startpc1 = (char)startpc;
1502 char endpc1 = (char)endpc;
1503 char handler_pc1 = (char)handler_pc;
1504 if (startpc1 == startpc &&
1505 endpc1 == endpc &&
1506 handler_pc1 == handler_pc) {
1507 code.addCatch(startpc1, endpc1, handler_pc1,
1508 (char)catch_type);
1509 } else {
1510 if (!useJsrLocally && !target.generateStackMapTable()) {
1511 useJsrLocally = true;
1512 throw new CodeSizeOverflow();
1513 } else {
1514 log.error(pos, "limit.code.too.large.for.try.stmt");
1515 nerrs++;
1516 }
1517 }
1518 }
1519
1520 /** Very roughly estimate the number of instructions needed for
1521 * the given tree.
1522 */
1523 int estimateCodeComplexity(JCTree tree) {
1524 if (tree == null) return 0;
1525 class ComplexityScanner extends TreeScanner {
1526 int complexity = 0;
1527 public void scan(JCTree tree) {
1528 if (complexity > jsrlimit) return;
1529 super.scan(tree);
1530 }
1531 public void visitClassDef(JCClassDecl tree) {}
1532 public void visitDoLoop(JCDoWhileLoop tree)
1533 { super.visitDoLoop(tree); complexity++; }
1534 public void visitWhileLoop(JCWhileLoop tree)
1535 { super.visitWhileLoop(tree); complexity++; }
1536 public void visitForLoop(JCForLoop tree)
1537 { super.visitForLoop(tree); complexity++; }
1538 public void visitSwitch(JCSwitch tree)
1539 { super.visitSwitch(tree); complexity+=5; }
1540 public void visitCase(JCCase tree)
1541 { super.visitCase(tree); complexity++; }
1542 public void visitSynchronized(JCSynchronized tree)
1543 { super.visitSynchronized(tree); complexity+=6; }
1544 public void visitTry(JCTry tree)
1545 { super.visitTry(tree);
1546 if (tree.finalizer != null) complexity+=6; }
1547 public void visitCatch(JCCatch tree)
1548 { super.visitCatch(tree); complexity+=2; }
1549 public void visitConditional(JCConditional tree)
1550 { super.visitConditional(tree); complexity+=2; }
1551 public void visitIf(JCIf tree)
1552 { super.visitIf(tree); complexity+=2; }
1553 // note: for break, continue, and return we don't take unwind() into account.
1554 public void visitBreak(JCBreak tree)
1555 { super.visitBreak(tree); complexity+=1; }
1556 public void visitContinue(JCContinue tree)
1557 { super.visitContinue(tree); complexity+=1; }
1558 public void visitReturn(JCReturn tree)
1559 { super.visitReturn(tree); complexity+=1; }
1560 public void visitThrow(JCThrow tree)
1561 { super.visitThrow(tree); complexity+=1; }
1562 public void visitAssert(JCAssert tree)
1563 { super.visitAssert(tree); complexity+=5; }
1564 public void visitApply(JCMethodInvocation tree)
1565 { super.visitApply(tree); complexity+=2; }
1566 public void visitNewClass(JCNewClass tree)
1567 { scan(tree.encl); scan(tree.args); complexity+=2; }
1568 public void visitNewArray(JCNewArray tree)
1569 { super.visitNewArray(tree); complexity+=5; }
1570 public void visitAssign(JCAssign tree)
1571 { super.visitAssign(tree); complexity+=1; }
1572 public void visitAssignop(JCAssignOp tree)
1573 { super.visitAssignop(tree); complexity+=2; }
1574 public void visitUnary(JCUnary tree)
1575 { complexity+=1;
1576 if (tree.type.constValue() == null) super.visitUnary(tree); }
1577 public void visitBinary(JCBinary tree)
1578 { complexity+=1;
1579 if (tree.type.constValue() == null) super.visitBinary(tree); }
1580 public void visitTypeTest(JCInstanceOf tree)
1581 { super.visitTypeTest(tree); complexity+=1; }
1582 public void visitIndexed(JCArrayAccess tree)
1583 { super.visitIndexed(tree); complexity+=1; }
1584 public void visitSelect(JCFieldAccess tree)
1585 { super.visitSelect(tree);
1586 if (tree.sym.kind == VAR) complexity+=1; }
1587 public void visitIdent(JCIdent tree) {
1588 if (tree.sym.kind == VAR) {
1589 complexity+=1;
1590 if (tree.type.constValue() == null &&
1591 tree.sym.owner.kind == TYP)
1592 complexity+=1;
1593 }
1594 }
1595 public void visitLiteral(JCLiteral tree)
1596 { complexity+=1; }
1597 public void visitTree(JCTree tree) {}
1598 public void visitWildcard(JCWildcard tree) {
1599 throw new AssertionError(this.getClass().getName());
1600 }
1601 }
1602 ComplexityScanner scanner = new ComplexityScanner();
1603 tree.accept(scanner);
1604 return scanner.complexity;
1605 }
1606
1607 public void visitIf(JCIf tree) {
1608 int limit = code.nextreg;
1609 Chain thenExit = null;
1610 CondItem c = genCond(TreeInfo.skipParens(tree.cond),
1611 CRT_FLOW_CONTROLLER);
1612 Chain elseChain = c.jumpFalse();
1613 if (!c.isFalse()) {
1614 code.resolve(c.trueJumps);
1615 genStat(tree.thenpart, env, CRT_STATEMENT | CRT_FLOW_TARGET);
1616 thenExit = code.branch(goto_);
1617 }
1618 if (elseChain != null) {
1619 code.resolve(elseChain);
1620 if (tree.elsepart != null)
1621 genStat(tree.elsepart, env,CRT_STATEMENT | CRT_FLOW_TARGET);
1622 }
1623 code.resolve(thenExit);
1624 code.endScopes(limit);
1625 }
1626
1627 public void visitExec(JCExpressionStatement tree) {
1628 // Optimize x++ to ++x and x-- to --x.
1629 JCExpression e = tree.expr;
1630 switch (e.getTag()) {
1631 case JCTree.POSTINC:
1632 ((JCUnary) e).setTag(JCTree.PREINC);
1633 break;
1634 case JCTree.POSTDEC:
1635 ((JCUnary) e).setTag(JCTree.PREDEC);
1636 break;
1637 }
1638 genExpr(tree.expr, tree.expr.type).drop();
1639 }
1640
1641 public void visitBreak(JCBreak tree) {
1642 Env<GenContext> targetEnv = unwind(tree.target, env);
1643 Assert.check(code.state.stacksize == 0);
1644 targetEnv.info.addExit(code.branch(goto_));
1645 endFinalizerGaps(env, targetEnv);
1646 }
1647
1648 public void visitContinue(JCContinue tree) {
1649 Env<GenContext> targetEnv = unwind(tree.target, env);
1650 Assert.check(code.state.stacksize == 0);
1651 targetEnv.info.addCont(code.branch(goto_));
1652 endFinalizerGaps(env, targetEnv);
1653 }
1654
1655 public void visitReturn(JCReturn tree) {
1656 int limit = code.nextreg;
1657 final Env<GenContext> targetEnv;
1658 if (tree.expr != null) {
1659 Item r = genExpr(tree.expr, pt).load();
1660 if (hasFinally(env.enclMethod, env)) {
1661 r = makeTemp(pt);
1662 r.store();
1663 }
1664 targetEnv = unwind(env.enclMethod, env);
1665 r.load();
1666 code.emitop0(ireturn + Code.truncate(Code.typecode(pt)));
1667 } else {
1668 targetEnv = unwind(env.enclMethod, env);
1669 code.emitop0(return_);
1670 }
1671 endFinalizerGaps(env, targetEnv);
1672 code.endScopes(limit);
1673 }
1674
1675 public void visitThrow(JCThrow tree) {
1676 genExpr(tree.expr, tree.expr.type).load();
1677 code.emitop0(athrow);
1678 }
1679
1680 /* ************************************************************************
1681 * Visitor methods for expressions
1682 *************************************************************************/
1683
1684 public void visitApply(JCMethodInvocation tree) {
1685 // Generate code for method.
1686 Item m = genExpr(tree.meth, methodType);
1687 // Generate code for all arguments, where the expected types are
1688 // the parameters of the method's external type (that is, any implicit
1689 // outer instance of a super(...) call appears as first parameter).
1690 genArgs(tree.args,
1691 TreeInfo.symbol(tree.meth).externalType(types).getParameterTypes());
1692 code.statBegin(tree.pos);
1693 code.markStatBegin();
1694 result = m.invoke();
1695 }
1696
1697 public void visitConditional(JCConditional tree) {
1698 Chain thenExit = null;
1699 CondItem c = genCond(tree.cond, CRT_FLOW_CONTROLLER);
1700 Chain elseChain = c.jumpFalse();
1701 if (!c.isFalse()) {
1702 code.resolve(c.trueJumps);
1703 int startpc = genCrt ? code.curPc() : 0;
1704 genExpr(tree.truepart, pt).load();
1705 code.state.forceStackTop(tree.type);
1706 if (genCrt) code.crt.put(tree.truepart, CRT_FLOW_TARGET,
1707 startpc, code.curPc());
1708 thenExit = code.branch(goto_);
1709 }
1710 if (elseChain != null) {
1711 code.resolve(elseChain);
1712 int startpc = genCrt ? code.curPc() : 0;
1713 genExpr(tree.falsepart, pt).load();
1714 code.state.forceStackTop(tree.type);
1715 if (genCrt) code.crt.put(tree.falsepart, CRT_FLOW_TARGET,
1716 startpc, code.curPc());
1717 }
1718 code.resolve(thenExit);
1719 result = items.makeStackItem(pt);
1720 }
1721
1722 public void visitNewClass(JCNewClass tree) {
1723 // Enclosing instances or anonymous classes should have been eliminated
1724 // by now.
1725 Assert.check(tree.encl == null && tree.def == null);
1726
1727 code.emitop2(new_, makeRef(tree.pos(), tree.type));
1728 code.emitop0(dup);
1729
1730 // Generate code for all arguments, where the expected types are
1731 // the parameters of the constructor's external type (that is,
1732 // any implicit outer instance appears as first parameter).
1733 genArgs(tree.args, tree.constructor.externalType(types).getParameterTypes());
1734
1735 items.makeMemberItem(tree.constructor, true).invoke();
1736 result = items.makeStackItem(tree.type);
1737 }
1738
1739 public void visitNewArray(JCNewArray tree) {
1740
1741 if (tree.elems != null) {
1742 Type elemtype = types.elemtype(tree.type);
1743 loadIntConst(tree.elems.length());
1744 Item arr = makeNewArray(tree.pos(), tree.type, 1);
1745 int i = 0;
1746 for (List<JCExpression> l = tree.elems; l.nonEmpty(); l = l.tail) {
1747 arr.duplicate();
1748 loadIntConst(i);
1749 i++;
1750 genExpr(l.head, elemtype).load();
1751 items.makeIndexedItem(elemtype).store();
1752 }
1753 result = arr;
1754 } else {
1755 for (List<JCExpression> l = tree.dims; l.nonEmpty(); l = l.tail) {
1756 genExpr(l.head, syms.intType).load();
1757 }
1758 result = makeNewArray(tree.pos(), tree.type, tree.dims.length());
1759 }
1760 }
1761 //where
1762 /** Generate code to create an array with given element type and number
1763 * of dimensions.
1764 */
1765 Item makeNewArray(DiagnosticPosition pos, Type type, int ndims) {
1766 Type elemtype = types.elemtype(type);
1767 if (types.dimensions(type) > ClassFile.MAX_DIMENSIONS) {
1768 log.error(pos, "limit.dimensions");
1769 nerrs++;
1770 }
1771 int elemcode = Code.arraycode(elemtype);
1772 if (elemcode == 0 || (elemcode == 1 && ndims == 1)) {
1773 code.emitAnewarray(makeRef(pos, elemtype), type);
1774 } else if (elemcode == 1) {
1775 code.emitMultianewarray(ndims, makeRef(pos, type), type);
1776 } else {
1777 code.emitNewarray(elemcode, type);
1778 }
1779 return items.makeStackItem(type);
1780 }
1781
1782 public void visitParens(JCParens tree) {
1783 result = genExpr(tree.expr, tree.expr.type);
1784 }
1785
1786 public void visitAssign(JCAssign tree) {
1787 Item l = genExpr(tree.lhs, tree.lhs.type);
1788 genExpr(tree.rhs, tree.lhs.type).load();
1789 result = items.makeAssignItem(l);
1790 }
1791
1792 public void visitAssignop(JCAssignOp tree) {
1793 OperatorSymbol operator = (OperatorSymbol) tree.operator;
1794 Item l;
1795 if (operator.opcode == string_add) {
1796 // Generate code to make a string buffer
1797 makeStringBuffer(tree.pos());
1798
1799 // Generate code for first string, possibly save one
1800 // copy under buffer
1801 l = genExpr(tree.lhs, tree.lhs.type);
1802 if (l.width() > 0) {
1803 code.emitop0(dup_x1 + 3 * (l.width() - 1));
1804 }
1805
1806 // Load first string and append to buffer.
1807 l.load();
1808 appendString(tree.lhs);
1809
1810 // Append all other strings to buffer.
1811 appendStrings(tree.rhs);
1812
1813 // Convert buffer to string.
1814 bufferToString(tree.pos());
1815 } else {
1816 // Generate code for first expression
1817 l = genExpr(tree.lhs, tree.lhs.type);
1818
1819 // If we have an increment of -32768 to +32767 of a local
1820 // int variable we can use an incr instruction instead of
1821 // proceeding further.
1822 if ((tree.getTag() == JCTree.PLUS_ASG || tree.getTag() == JCTree.MINUS_ASG) &&
1823 l instanceof LocalItem &&
1824 tree.lhs.type.tag <= INT &&
1825 tree.rhs.type.tag <= INT &&
1826 tree.rhs.type.constValue() != null) {
1827 int ival = ((Number) tree.rhs.type.constValue()).intValue();
1828 if (tree.getTag() == JCTree.MINUS_ASG) ival = -ival;
1829 ((LocalItem)l).incr(ival);
1830 result = l;
1831 return;
1832 }
1833 // Otherwise, duplicate expression, load one copy
1834 // and complete binary operation.
1835 l.duplicate();
1836 l.coerce(operator.type.getParameterTypes().head).load();
1837 completeBinop(tree.lhs, tree.rhs, operator).coerce(tree.lhs.type);
1838 }
1839 result = items.makeAssignItem(l);
1840 }
1841
1842 public void visitUnary(JCUnary tree) {
1843 OperatorSymbol operator = (OperatorSymbol)tree.operator;
1844 if (tree.getTag() == JCTree.NOT) {
1845 CondItem od = genCond(tree.arg, false);
1846 result = od.negate();
1847 } else {
1848 Item od = genExpr(tree.arg, operator.type.getParameterTypes().head);
1849 switch (tree.getTag()) {
1850 case JCTree.POS:
1851 result = od.load();
1852 break;
1853 case JCTree.NEG:
1854 result = od.load();
1855 code.emitop0(operator.opcode);
1856 break;
1857 case JCTree.COMPL:
1858 result = od.load();
1859 emitMinusOne(od.typecode);
1860 code.emitop0(operator.opcode);
1861 break;
1862 case JCTree.PREINC: case JCTree.PREDEC:
1863 od.duplicate();
1864 if (od instanceof LocalItem &&
1865 (operator.opcode == iadd || operator.opcode == isub)) {
1866 ((LocalItem)od).incr(tree.getTag() == JCTree.PREINC ? 1 : -1);
1867 result = od;
1868 } else {
1869 od.load();
1870 code.emitop0(one(od.typecode));
1871 code.emitop0(operator.opcode);
1872 // Perform narrowing primitive conversion if byte,
1873 // char, or short. Fix for 4304655.
1874 if (od.typecode != INTcode &&
1875 Code.truncate(od.typecode) == INTcode)
1876 code.emitop0(int2byte + od.typecode - BYTEcode);
1877 result = items.makeAssignItem(od);
1878 }
1879 break;
1880 case JCTree.POSTINC: case JCTree.POSTDEC:
1881 od.duplicate();
1882 if (od instanceof LocalItem &&
1883 (operator.opcode == iadd || operator.opcode == isub)) {
1884 Item res = od.load();
1885 ((LocalItem)od).incr(tree.getTag() == JCTree.POSTINC ? 1 : -1);
1886 result = res;
1887 } else {
1888 Item res = od.load();
1889 od.stash(od.typecode);
1890 code.emitop0(one(od.typecode));
1891 code.emitop0(operator.opcode);
1892 // Perform narrowing primitive conversion if byte,
1893 // char, or short. Fix for 4304655.
1894 if (od.typecode != INTcode &&
1895 Code.truncate(od.typecode) == INTcode)
1896 code.emitop0(int2byte + od.typecode - BYTEcode);
1897 od.store();
1898 result = res;
1899 }
1900 break;
1901 case JCTree.NULLCHK:
1902 result = od.load();
1903 code.emitop0(dup);
1904 genNullCheck(tree.pos());
1905 break;
1906 default:
1907 Assert.error();
1908 }
1909 }
1910 }
1911
1912 /** Generate a null check from the object value at stack top. */
1913 private void genNullCheck(DiagnosticPosition pos) {
1914 callMethod(pos, syms.objectType, names.getClass,
1915 List.<Type>nil(), false);
1916 code.emitop0(pop);
1917 }
1918
1919 public void visitBinary(JCBinary tree) {
1920 OperatorSymbol operator = (OperatorSymbol)tree.operator;
1921 if (operator.opcode == string_add) {
1922 // Create a string buffer.
1923 makeStringBuffer(tree.pos());
1924 // Append all strings to buffer.
1925 appendStrings(tree);
1926 // Convert buffer to string.
1927 bufferToString(tree.pos());
1928 result = items.makeStackItem(syms.stringType);
1929 } else if (tree.getTag() == JCTree.AND) {
1930 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
1931 if (!lcond.isFalse()) {
1932 Chain falseJumps = lcond.jumpFalse();
1933 code.resolve(lcond.trueJumps);
1934 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
1935 result = items.
1936 makeCondItem(rcond.opcode,
1937 rcond.trueJumps,
1938 Code.mergeChains(falseJumps,
1939 rcond.falseJumps));
1940 } else {
1941 result = lcond;
1942 }
1943 } else if (tree.getTag() == JCTree.OR) {
1944 CondItem lcond = genCond(tree.lhs, CRT_FLOW_CONTROLLER);
1945 if (!lcond.isTrue()) {
1946 Chain trueJumps = lcond.jumpTrue();
1947 code.resolve(lcond.falseJumps);
1948 CondItem rcond = genCond(tree.rhs, CRT_FLOW_TARGET);
1949 result = items.
1950 makeCondItem(rcond.opcode,
1951 Code.mergeChains(trueJumps, rcond.trueJumps),
1952 rcond.falseJumps);
1953 } else {
1954 result = lcond;
1955 }
1956 } else {
1957 Item od = genExpr(tree.lhs, operator.type.getParameterTypes().head);
1958 od.load();
1959 result = completeBinop(tree.lhs, tree.rhs, operator);
1960 }
1961 }
1962 //where
1963 /** Make a new string buffer.
1964 */
1965 void makeStringBuffer(DiagnosticPosition pos) {
1966 code.emitop2(new_, makeRef(pos, stringBufferType));
1967 code.emitop0(dup);
1968 callMethod(
1969 pos, stringBufferType, names.init, List.<Type>nil(), false);
1970 }
1971
1972 /** Append value (on tos) to string buffer (on tos - 1).
1973 */
1974 void appendString(JCTree tree) {
1975 Type t = tree.type.baseType();
1976 if (t.tag > lastBaseTag && t.tsym != syms.stringType.tsym) {
1977 t = syms.objectType;
1978 }
1979 items.makeMemberItem(getStringBufferAppend(tree, t), false).invoke();
1980 }
1981 Symbol getStringBufferAppend(JCTree tree, Type t) {
1982 Assert.checkNull(t.constValue());
1983 Symbol method = stringBufferAppend.get(t);
1984 if (method == null) {
1985 method = rs.resolveInternalMethod(tree.pos(),
1986 attrEnv,
1987 stringBufferType,
1988 names.append,
1989 List.of(t),
1990 null);
1991 stringBufferAppend.put(t, method);
1992 }
1993 return method;
1994 }
1995
1996 /** Add all strings in tree to string buffer.
1997 */
1998 void appendStrings(JCTree tree) {
1999 tree = TreeInfo.skipParens(tree);
2000 if (tree.getTag() == JCTree.PLUS && tree.type.constValue() == null) {
2001 JCBinary op = (JCBinary) tree;
2002 if (op.operator.kind == MTH &&
2003 ((OperatorSymbol) op.operator).opcode == string_add) {
2004 appendStrings(op.lhs);
2005 appendStrings(op.rhs);
2006 return;
2007 }
2008 }
2009 genExpr(tree, tree.type).load();
2010 appendString(tree);
2011 }
2012
2013 /** Convert string buffer on tos to string.
2014 */
2015 void bufferToString(DiagnosticPosition pos) {
2016 callMethod(
2017 pos,
2018 stringBufferType,
2019 names.toString,
2020 List.<Type>nil(),
2021 false);
2022 }
2023
2024 /** Complete generating code for operation, with left operand
2025 * already on stack.
2026 * @param lhs The tree representing the left operand.
2027 * @param rhs The tree representing the right operand.
2028 * @param operator The operator symbol.
2029 */
2030 Item completeBinop(JCTree lhs, JCTree rhs, OperatorSymbol operator) {
2031 MethodType optype = (MethodType)operator.type;
2032 int opcode = operator.opcode;
2033 if (opcode >= if_icmpeq && opcode <= if_icmple &&
2034 rhs.type.constValue() instanceof Number &&
2035 ((Number) rhs.type.constValue()).intValue() == 0) {
2036 opcode = opcode + (ifeq - if_icmpeq);
2037 } else if (opcode >= if_acmpeq && opcode <= if_acmpne &&
2038 TreeInfo.isNull(rhs)) {
2039 opcode = opcode + (if_acmp_null - if_acmpeq);
2040 } else {
2041 // The expected type of the right operand is
2042 // the second parameter type of the operator, except for
2043 // shifts with long shiftcount, where we convert the opcode
2044 // to a short shift and the expected type to int.
2045 Type rtype = operator.erasure(types).getParameterTypes().tail.head;
2046 if (opcode >= ishll && opcode <= lushrl) {
2047 opcode = opcode + (ishl - ishll);
2048 rtype = syms.intType;
2049 }
2050 // Generate code for right operand and load.
2051 genExpr(rhs, rtype).load();
2052 // If there are two consecutive opcode instructions,
2053 // emit the first now.
2054 if (opcode >= (1 << preShift)) {
2055 code.emitop0(opcode >> preShift);
2056 opcode = opcode & 0xFF;
2057 }
2058 }
2059 if (opcode >= ifeq && opcode <= if_acmpne ||
2060 opcode == if_acmp_null || opcode == if_acmp_nonnull) {
2061 return items.makeCondItem(opcode);
2062 } else {
2063 code.emitop0(opcode);
2064 return items.makeStackItem(optype.restype);
2065 }
2066 }
2067
2068 public void visitTypeCast(JCTypeCast tree) {
2069 result = genExpr(tree.expr, tree.clazz.type).load();
2070 // Additional code is only needed if we cast to a reference type
2071 // which is not statically a supertype of the expression's type.
2072 // For basic types, the coerce(...) in genExpr(...) will do
2073 // the conversion.
2074 if (tree.clazz.type.tag > lastBaseTag &&
2075 types.asSuper(tree.expr.type, tree.clazz.type.tsym) == null) {
2076 code.emitop2(checkcast, makeRef(tree.pos(), tree.clazz.type));
2077 }
2078 }
2079
2080 public void visitWildcard(JCWildcard tree) {
2081 throw new AssertionError(this.getClass().getName());
2082 }
2083
2084 public void visitTypeTest(JCInstanceOf tree) {
2085 genExpr(tree.expr, tree.expr.type).load();
2086 code.emitop2(instanceof_, makeRef(tree.pos(), tree.clazz.type));
2087 result = items.makeStackItem(syms.booleanType);
2088 }
2089
2090 public void visitIndexed(JCArrayAccess tree) {
2091 genExpr(tree.indexed, tree.indexed.type).load();
2092 genExpr(tree.index, syms.intType).load();
2093 result = items.makeIndexedItem(tree.type);
2094 }
2095
2096 public void visitIdent(JCIdent tree) {
2097 Symbol sym = tree.sym;
2098 if (tree.name == names._this || tree.name == names._super) {
2099 Item res = tree.name == names._this
2100 ? items.makeThisItem()
2101 : items.makeSuperItem();
2102 if (sym.kind == MTH) {
2103 // Generate code to address the constructor.
2104 res.load();
2105 res = items.makeMemberItem(sym, true);
2106 }
2107 result = res;
2108 } else if (sym.kind == VAR && sym.owner.kind == MTH) {
2109 result = items.makeLocalItem((VarSymbol)sym);
2110 } else if ((sym.flags() & STATIC) != 0) {
2111 if (!isAccessSuper(env.enclMethod))
2112 sym = binaryQualifier(sym, env.enclClass.type);
2113 result = items.makeStaticItem(sym);
2114 } else {
2115 items.makeThisItem().load();
2116 sym = binaryQualifier(sym, env.enclClass.type);
2117 result = items.makeMemberItem(sym, (sym.flags() & PRIVATE) != 0);
2118 }
2119 }
2120
2121 public void visitSelect(JCFieldAccess tree) {
2122 Symbol sym = tree.sym;
2123
2124 if (tree.name == names._class) {
2125 Assert.check(target.hasClassLiterals());
2126 code.emitop2(ldc2, makeRef(tree.pos(), tree.selected.type));
2127 result = items.makeStackItem(pt);
2128 return;
2129 }
2130
2131 Symbol ssym = TreeInfo.symbol(tree.selected);
2132
2133 // Are we selecting via super?
2134 boolean selectSuper =
2135 ssym != null && (ssym.kind == TYP || ssym.name == names._super);
2136
2137 // Are we accessing a member of the superclass in an access method
2138 // resulting from a qualified super?
2139 boolean accessSuper = isAccessSuper(env.enclMethod);
2140
2141 Item base = (selectSuper)
2142 ? items.makeSuperItem()
2143 : genExpr(tree.selected, tree.selected.type);
2144
2145 if (sym.kind == VAR && ((VarSymbol) sym).getConstValue() != null) {
2146 // We are seeing a variable that is constant but its selecting
2147 // expression is not.
2148 if ((sym.flags() & STATIC) != 0) {
2149 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2150 base = base.load();
2151 base.drop();
2152 } else {
2153 base.load();
2154 genNullCheck(tree.selected.pos());
2155 }
2156 result = items.
2157 makeImmediateItem(sym.type, ((VarSymbol) sym).getConstValue());
2158 } else {
2159 if (!accessSuper)
2160 sym = binaryQualifier(sym, tree.selected.type);
2161 if ((sym.flags() & STATIC) != 0) {
2162 if (!selectSuper && (ssym == null || ssym.kind != TYP))
2163 base = base.load();
2164 base.drop();
2165 result = items.makeStaticItem(sym);
2166 } else {
2167 base.load();
2168 if (sym == syms.lengthVar) {
2169 code.emitop0(arraylength);
2170 result = items.makeStackItem(syms.intType);
2171 } else {
2172 result = items.
2173 makeMemberItem(sym,
2174 (sym.flags() & PRIVATE) != 0 ||
2175 selectSuper || accessSuper);
2176 }
2177 }
2178 }
2179 }
2180
2181 public void visitLiteral(JCLiteral tree) {
2182 if (tree.type.tag == TypeTags.BOT) {
2183 code.emitop0(aconst_null);
2184 if (types.dimensions(pt) > 1) {
2185 code.emitop2(checkcast, makeRef(tree.pos(), pt));
2186 result = items.makeStackItem(pt);
2187 } else {
2188 result = items.makeStackItem(tree.type);
2189 }
2190 }
2191 else
2192 result = items.makeImmediateItem(tree.type, tree.value);
2193 }
2194
2195 public void visitLetExpr(LetExpr tree) {
2196 int limit = code.nextreg;
2197 genStats(tree.defs, env);
2198 result = genExpr(tree.expr, tree.expr.type).load();
2199 code.endScopes(limit);
2200 }
2201
2202 /* ************************************************************************
2203 * main method
2204 *************************************************************************/
2205
2206 /** Generate code for a class definition.
2207 * @param env The attribution environment that belongs to the
2208 * outermost class containing this class definition.
2209 * We need this for resolving some additional symbols.
2210 * @param cdef The tree representing the class definition.
2211 * @return True if code is generated with no errors.
2212 */
2213 public boolean genClass(Env<AttrContext> env, JCClassDecl cdef) {
2214 try {
2215 attrEnv = env;
2216 ClassSymbol c = cdef.sym;
2217 this.toplevel = env.toplevel;
2218 this.endPositions = toplevel.endPositions;
2219 // If this is a class definition requiring Miranda methods,
2220 // add them.
2221 if (generateIproxies &&
2222 (c.flags() & (INTERFACE|ABSTRACT)) == ABSTRACT
2223 && !allowGenerics // no Miranda methods available with generics
2224 )
2225 implementInterfaceMethods(c);
2226 cdef.defs = normalizeDefs(cdef.defs, c);
2227 c.pool = pool;
2228 pool.reset();
2229 Env<GenContext> localEnv =
2230 new Env<GenContext>(cdef, new GenContext());
2231 localEnv.toplevel = env.toplevel;
2232 localEnv.enclClass = cdef;
2233 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2234 genDef(l.head, localEnv);
2235 }
2236 if (pool.numEntries() > Pool.MAX_ENTRIES) {
2237 log.error(cdef.pos(), "limit.pool");
2238 nerrs++;
2239 }
2240 if (nerrs != 0) {
2241 // if errors, discard code
2242 for (List<JCTree> l = cdef.defs; l.nonEmpty(); l = l.tail) {
2243 if (l.head.getTag() == JCTree.METHODDEF)
2244 ((JCMethodDecl) l.head).sym.code = null;
2245 }
2246 }
2247 cdef.defs = List.nil(); // discard trees
2248 return nerrs == 0;
2249 } finally {
2250 // note: this method does NOT support recursion.
2251 attrEnv = null;
2252 this.env = null;
2253 toplevel = null;
2254 endPositions = null;
2255 nerrs = 0;
2256 }
2257 }
2258
2259 /* ************************************************************************
2260 * Auxiliary classes
2261 *************************************************************************/
2262
2263 /** An abstract class for finalizer generation.
2264 */
2265 abstract class GenFinalizer {
2266 /** Generate code to clean up when unwinding. */
2267 abstract void gen();
2268
2269 /** Generate code to clean up at last. */
2270 abstract void genLast();
2271
2272 /** Does this finalizer have some nontrivial cleanup to perform? */
2273 boolean hasFinalizer() { return true; }
2274 }
2275
2276 /** code generation contexts,
2277 * to be used as type parameter for environments.
2278 */
2279 static class GenContext {
2280
2281 /** A chain for all unresolved jumps that exit the current environment.
2282 */
2283 Chain exit = null;
2284
2285 /** A chain for all unresolved jumps that continue in the
2286 * current environment.
2287 */
2288 Chain cont = null;
2289
2290 /** A closure that generates the finalizer of the current environment.
2291 * Only set for Synchronized and Try contexts.
2292 */
2293 GenFinalizer finalize = null;
2294
2295 /** Is this a switch statement? If so, allocate registers
2296 * even when the variable declaration is unreachable.
2297 */
2298 boolean isSwitch = false;
2299
2300 /** A list buffer containing all gaps in the finalizer range,
2301 * where a catch all exception should not apply.
2302 */
2303 ListBuffer<Integer> gaps = null;
2304
2305 /** Add given chain to exit chain.
2306 */
2307 void addExit(Chain c) {
2308 exit = Code.mergeChains(c, exit);
2309 }
2310
2311 /** Add given chain to cont chain.
2312 */
2313 void addCont(Chain c) {
2314 cont = Code.mergeChains(c, cont);
2315 }
2316 }
2317 }