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.comp;
27
28 import java.util;
29
30 import javax.lang.model.element.ElementKind;
31
32 import com.sun.tools.javac.code;
33 import com.sun.tools.javac.code.Symbol;
34 import com.sun.tools.javac.tree;
35 import com.sun.tools.javac.tree.JCTree;
36 import com.sun.tools.javac.util;
37 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
38 import com.sun.tools.javac.util.List;
39
40 import static com.sun.tools.javac.code.Flags.*;
41 import static com.sun.tools.javac.code.Kinds.*;
42 import static com.sun.tools.javac.code.TypeTags.*;
43
44 /** This pass translates Generic Java to conventional Java.
45 *
46 * <p><b>This is NOT part of any supported API.
47 * If you write code that depends on this, you do so at your own risk.
48 * This code and its internal interfaces are subject to change or
49 * deletion without notice.</b>
50 */
51 public class TransTypes extends TreeTranslator {
52 /** The context key for the TransTypes phase. */
53 protected static final Context.Key<TransTypes> transTypesKey =
54 new Context.Key<TransTypes>();
55
56 /** Get the instance for this context. */
57 public static TransTypes instance(Context context) {
58 TransTypes instance = context.get(transTypesKey);
59 if (instance == null)
60 instance = new TransTypes(context);
61 return instance;
62 }
63
64 private Names names;
65 private Log log;
66 private Symtab syms;
67 private TreeMaker make;
68 private Enter enter;
69 private boolean allowEnums;
70 private Types types;
71 private final Resolve resolve;
72
73 /**
74 * Flag to indicate whether or not to generate bridge methods.
75 * For pre-Tiger source there is no need for bridge methods, so it
76 * can be skipped to get better performance for -source 1.4 etc.
77 */
78 private final boolean addBridges;
79
80 protected TransTypes(Context context) {
81 context.put(transTypesKey, this);
82 names = Names.instance(context);
83 log = Log.instance(context);
84 syms = Symtab.instance(context);
85 enter = Enter.instance(context);
86 overridden = new HashMap<MethodSymbol,MethodSymbol>();
87 Source source = Source.instance(context);
88 allowEnums = source.allowEnums();
89 addBridges = source.addBridges();
90 types = Types.instance(context);
91 make = TreeMaker.instance(context);
92 resolve = Resolve.instance(context);
93 }
94
95 /** A hashtable mapping bridge methods to the methods they override after
96 * type erasure.
97 */
98 Map<MethodSymbol,MethodSymbol> overridden;
99
100 /** Construct an attributed tree for a cast of expression to target type,
101 * unless it already has precisely that type.
102 * @param tree The expression tree.
103 * @param target The target type.
104 */
105 JCExpression cast(JCExpression tree, Type target) {
106 int oldpos = make.pos;
107 make.at(tree.pos);
108 if (!types.isSameType(tree.type, target)) {
109 if (!resolve.isAccessible(env, target.tsym))
110 resolve.logAccessError(env, tree, target);
111 tree = make.TypeCast(make.Type(target), tree).setType(target);
112 }
113 make.pos = oldpos;
114 return tree;
115 }
116
117 /** Construct an attributed tree to coerce an expression to some erased
118 * target type, unless the expression is already assignable to that type.
119 * If target type is a constant type, use its base type instead.
120 * @param tree The expression tree.
121 * @param target The target type.
122 */
123 JCExpression coerce(JCExpression tree, Type target) {
124 Type btarget = target.baseType();
125 if (tree.type.isPrimitive() == target.isPrimitive()) {
126 return types.isAssignable(tree.type, btarget, Warner.noWarnings)
127 ? tree
128 : cast(tree, btarget);
129 }
130 return tree;
131 }
132
133 /** Given an erased reference type, assume this type as the tree's type.
134 * Then, coerce to some given target type unless target type is null.
135 * This operation is used in situations like the following:
136 *
137 * class Cell<A> { A value; }
138 * ...
139 * Cell<Integer> cell;
140 * Integer x = cell.value;
141 *
142 * Since the erasure of Cell.value is Object, but the type
143 * of cell.value in the assignment is Integer, we need to
144 * adjust the original type of cell.value to Object, and insert
145 * a cast to Integer. That is, the last assignment becomes:
146 *
147 * Integer x = (Integer)cell.value;
148 *
149 * @param tree The expression tree whose type might need adjustment.
150 * @param erasedType The expression's type after erasure.
151 * @param target The target type, which is usually the erasure of the
152 * expression's original type.
153 */
154 JCExpression retype(JCExpression tree, Type erasedType, Type target) {
155 // System.err.println("retype " + tree + " to " + erasedType);//DEBUG
156 if (erasedType.tag > lastBaseTag) {
157 if (target != null && target.isPrimitive())
158 target = erasure(tree.type);
159 tree.type = erasedType;
160 if (target != null) return coerce(tree, target);
161 }
162 return tree;
163 }
164
165 /** Translate method argument list, casting each argument
166 * to its corresponding type in a list of target types.
167 * @param _args The method argument list.
168 * @param parameters The list of target types.
169 * @param varargsElement The erasure of the varargs element type,
170 * or null if translating a non-varargs invocation
171 */
172 <T extends JCTree> List<T> translateArgs(List<T> _args,
173 List<Type> parameters,
174 Type varargsElement) {
175 if (parameters.isEmpty()) return _args;
176 List<T> args = _args;
177 while (parameters.tail.nonEmpty()) {
178 args.head = translate(args.head, parameters.head);
179 args = args.tail;
180 parameters = parameters.tail;
181 }
182 Type parameter = parameters.head;
183 Assert.check(varargsElement != null || args.length() == 1);
184 if (varargsElement != null) {
185 while (args.nonEmpty()) {
186 args.head = translate(args.head, varargsElement);
187 args = args.tail;
188 }
189 } else {
190 args.head = translate(args.head, parameter);
191 }
192 return _args;
193 }
194
195 /** Add a bridge definition and enter corresponding method symbol in
196 * local scope of origin.
197 *
198 * @param pos The source code position to be used for the definition.
199 * @param meth The method for which a bridge needs to be added
200 * @param impl That method's implementation (possibly the method itself)
201 * @param origin The class to which the bridge will be added
202 * @param hypothetical
203 * True if the bridge method is not strictly necessary in the
204 * binary, but is represented in the symbol table to detect
205 * erasure clashes.
206 * @param bridges The list buffer to which the bridge will be added
207 */
208 void addBridge(DiagnosticPosition pos,
209 MethodSymbol meth,
210 MethodSymbol impl,
211 ClassSymbol origin,
212 boolean hypothetical,
213 ListBuffer<JCTree> bridges) {
214 make.at(pos);
215 Type origType = types.memberType(origin.type, meth);
216 Type origErasure = erasure(origType);
217
218 // Create a bridge method symbol and a bridge definition without a body.
219 Type bridgeType = meth.erasure(types);
220 long flags = impl.flags() & AccessFlags | SYNTHETIC | BRIDGE;
221 if (hypothetical) flags |= HYPOTHETICAL;
222 MethodSymbol bridge = new MethodSymbol(flags,
223 meth.name,
224 bridgeType,
225 origin);
226 if (!hypothetical) {
227 JCMethodDecl md = make.MethodDef(bridge, null);
228
229 // The bridge calls this.impl(..), if we have an implementation
230 // in the current class, super.impl(...) otherwise.
231 JCExpression receiver = (impl.owner == origin)
232 ? make.This(origin.erasure(types))
233 : make.Super(types.supertype(origin.type).tsym.erasure(types), origin);
234
235 // The type returned from the original method.
236 Type calltype = erasure(impl.type.getReturnType());
237
238 // Construct a call of this.impl(params), or super.impl(params),
239 // casting params and possibly results as needed.
240 JCExpression call =
241 make.Apply(
242 null,
243 make.Select(receiver, impl).setType(calltype),
244 translateArgs(make.Idents(md.params), origErasure.getParameterTypes(), null))
245 .setType(calltype);
246 JCStatement stat = (origErasure.getReturnType().tag == VOID)
247 ? make.Exec(call)
248 : make.Return(coerce(call, bridgeType.getReturnType()));
249 md.body = make.Block(0, List.of(stat));
250
251 // Add bridge to `bridges' buffer
252 bridges.append(md);
253 }
254
255 // Add bridge to scope of enclosing class and `overridden' table.
256 origin.members().enter(bridge);
257 overridden.put(bridge, meth);
258 }
259
260 /** Add bridge if given symbol is a non-private, non-static member
261 * of the given class, which is either defined in the class or non-final
262 * inherited, and one of the two following conditions holds:
263 * 1. The method's type changes in the given class, as compared to the
264 * class where the symbol was defined, (in this case
265 * we have extended a parameterized class with non-trivial parameters).
266 * 2. The method has an implementation with a different erased return type.
267 * (in this case we have used co-variant returns).
268 * If a bridge already exists in some other class, no new bridge is added.
269 * Instead, it is checked that the bridge symbol overrides the method symbol.
270 * (Spec ???).
271 * todo: what about bridges for privates???
272 *
273 * @param pos The source code position to be used for the definition.
274 * @param sym The symbol for which a bridge might have to be added.
275 * @param origin The class in which the bridge would go.
276 * @param bridges The list buffer to which the bridge would be added.
277 */
278 void addBridgeIfNeeded(DiagnosticPosition pos,
279 Symbol sym,
280 ClassSymbol origin,
281 ListBuffer<JCTree> bridges) {
282 if (sym.kind == MTH &&
283 sym.name != names.init &&
284 (sym.flags() & (PRIVATE | STATIC)) == 0 &&
285 (sym.flags() & (SYNTHETIC | OVERRIDE_BRIDGE)) != SYNTHETIC &&
286 sym.isMemberOf(origin, types))
287 {
288 MethodSymbol meth = (MethodSymbol)sym;
289 MethodSymbol bridge = meth.binaryImplementation(origin, types);
290 MethodSymbol impl = meth.implementation(origin, types, true, overrideBridgeFilter);
291 if (bridge == null ||
292 bridge == meth ||
293 (impl != null && !bridge.owner.isSubClass(impl.owner, types))) {
294 // No bridge was added yet.
295 if (impl != null && isBridgeNeeded(meth, impl, origin.type)) {
296 addBridge(pos, meth, impl, origin, bridge==impl, bridges);
297 } else if (impl == meth
298 && impl.owner != origin
299 && (impl.flags() & FINAL) == 0
300 && (meth.flags() & (ABSTRACT|PUBLIC)) == PUBLIC
301 && (origin.flags() & PUBLIC) > (impl.owner.flags() & PUBLIC)) {
302 // this is to work around a horrible but permanent
303 // reflection design error.
304 addBridge(pos, meth, impl, origin, false, bridges);
305 }
306 } else if ((bridge.flags() & (SYNTHETIC | OVERRIDE_BRIDGE)) == SYNTHETIC) {
307 MethodSymbol other = overridden.get(bridge);
308 if (other != null && other != meth) {
309 if (impl == null || !impl.overrides(other, origin, types, true)) {
310 // Bridge for other symbol pair was added
311 log.error(pos, "name.clash.same.erasure.no.override",
312 other, other.location(origin.type, types),
313 meth, meth.location(origin.type, types));
314 }
315 }
316 } else if (!bridge.overrides(meth, origin, types, true)) {
317 // Accidental binary override without source override.
318 if (bridge.owner == origin ||
319 types.asSuper(bridge.owner.type, meth.owner) == null)
320 // Don't diagnose the problem if it would already
321 // have been reported in the superclass
322 log.error(pos, "name.clash.same.erasure.no.override",
323 bridge, bridge.location(origin.type, types),
324 meth, meth.location(origin.type, types));
325 }
326 }
327 }
328 // where
329 Filter<Symbol> overrideBridgeFilter = new Filter<Symbol>() {
330 public boolean accepts(Symbol s) {
331 return (s.flags() & (SYNTHETIC | OVERRIDE_BRIDGE)) != SYNTHETIC;
332 }
333 };
334 /**
335 * @param method The symbol for which a bridge might have to be added
336 * @param impl The implementation of method
337 * @param dest The type in which the bridge would go
338 */
339 private boolean isBridgeNeeded(MethodSymbol method,
340 MethodSymbol impl,
341 Type dest) {
342 if (impl != method) {
343 // If either method or impl have different erasures as
344 // members of dest, a bridge is needed.
345 Type method_erasure = method.erasure(types);
346 if (!isSameMemberWhenErased(dest, method, method_erasure))
347 return true;
348 Type impl_erasure = impl.erasure(types);
349 if (!isSameMemberWhenErased(dest, impl, impl_erasure))
350 return true;
351
352 // If the erasure of the return type is different, a
353 // bridge is needed.
354 return !types.isSameType(impl_erasure.getReturnType(),
355 method_erasure.getReturnType());
356 } else {
357 // method and impl are the same...
358 if ((method.flags() & ABSTRACT) != 0) {
359 // ...and abstract so a bridge is not needed.
360 // Concrete subclasses will bridge as needed.
361 return false;
362 }
363
364 // The erasure of the return type is always the same
365 // for the same symbol. Reducing the three tests in
366 // the other branch to just one:
367 return !isSameMemberWhenErased(dest, method, method.erasure(types));
368 }
369 }
370 /**
371 * Lookup the method as a member of the type. Compare the
372 * erasures.
373 * @param type the class where to look for the method
374 * @param method the method to look for in class
375 * @param erasure the erasure of method
376 */
377 private boolean isSameMemberWhenErased(Type type,
378 MethodSymbol method,
379 Type erasure) {
380 return types.isSameType(erasure(types.memberType(type, method)),
381 erasure);
382 }
383
384 void addBridges(DiagnosticPosition pos,
385 TypeSymbol i,
386 ClassSymbol origin,
387 ListBuffer<JCTree> bridges) {
388 for (Scope.Entry e = i.members().elems; e != null; e = e.sibling)
389 addBridgeIfNeeded(pos, e.sym, origin, bridges);
390 for (List<Type> l = types.interfaces(i.type); l.nonEmpty(); l = l.tail)
391 addBridges(pos, l.head.tsym, origin, bridges);
392 }
393
394 /** Add all necessary bridges to some class appending them to list buffer.
395 * @param pos The source code position to be used for the bridges.
396 * @param origin The class in which the bridges go.
397 * @param bridges The list buffer to which the bridges are added.
398 */
399 void addBridges(DiagnosticPosition pos, ClassSymbol origin, ListBuffer<JCTree> bridges) {
400 Type st = types.supertype(origin.type);
401 while (st.tag == CLASS) {
402 // if (isSpecialization(st))
403 addBridges(pos, st.tsym, origin, bridges);
404 st = types.supertype(st);
405 }
406 for (List<Type> l = types.interfaces(origin.type); l.nonEmpty(); l = l.tail)
407 // if (isSpecialization(l.head))
408 addBridges(pos, l.head.tsym, origin, bridges);
409 }
410
411 /* ************************************************************************
412 * Visitor methods
413 *************************************************************************/
414
415 /** Visitor argument: proto-type.
416 */
417 private Type pt;
418
419 /** Visitor method: perform a type translation on tree.
420 */
421 public <T extends JCTree> T translate(T tree, Type pt) {
422 Type prevPt = this.pt;
423 try {
424 this.pt = pt;
425 return translate(tree);
426 } finally {
427 this.pt = prevPt;
428 }
429 }
430
431 /** Visitor method: perform a type translation on list of trees.
432 */
433 public <T extends JCTree> List<T> translate(List<T> trees, Type pt) {
434 Type prevPt = this.pt;
435 List<T> res;
436 try {
437 this.pt = pt;
438 res = translate(trees);
439 } finally {
440 this.pt = prevPt;
441 }
442 return res;
443 }
444
445 public void visitClassDef(JCClassDecl tree) {
446 translateClass(tree.sym);
447 result = tree;
448 }
449
450 JCMethodDecl currentMethod = null;
451 public void visitMethodDef(JCMethodDecl tree) {
452 JCMethodDecl previousMethod = currentMethod;
453 try {
454 currentMethod = tree;
455 tree.restype = translate(tree.restype, null);
456 tree.typarams = List.nil();
457 tree.params = translateVarDefs(tree.params);
458 tree.thrown = translate(tree.thrown, null);
459 tree.body = translate(tree.body, tree.sym.erasure(types).getReturnType());
460 tree.type = erasure(tree.type);
461 result = tree;
462 } finally {
463 currentMethod = previousMethod;
464 }
465
466 // Check that we do not introduce a name clash by erasing types.
467 for (Scope.Entry e = tree.sym.owner.members().lookup(tree.name);
468 e.sym != null;
469 e = e.next()) {
470 if (e.sym != tree.sym &&
471 types.isSameType(erasure(e.sym.type), tree.type)) {
472 log.error(tree.pos(),
473 "name.clash.same.erasure", tree.sym,
474 e.sym);
475 return;
476 }
477 }
478 }
479
480 public void visitVarDef(JCVariableDecl tree) {
481 tree.vartype = translate(tree.vartype, null);
482 tree.init = translate(tree.init, tree.sym.erasure(types));
483 tree.type = erasure(tree.type);
484 result = tree;
485 }
486
487 public void visitDoLoop(JCDoWhileLoop tree) {
488 tree.body = translate(tree.body);
489 tree.cond = translate(tree.cond, syms.booleanType);
490 result = tree;
491 }
492
493 public void visitWhileLoop(JCWhileLoop tree) {
494 tree.cond = translate(tree.cond, syms.booleanType);
495 tree.body = translate(tree.body);
496 result = tree;
497 }
498
499 public void visitForLoop(JCForLoop tree) {
500 tree.init = translate(tree.init, null);
501 if (tree.cond != null)
502 tree.cond = translate(tree.cond, syms.booleanType);
503 tree.step = translate(tree.step, null);
504 tree.body = translate(tree.body);
505 result = tree;
506 }
507
508 public void visitForeachLoop(JCEnhancedForLoop tree) {
509 tree.var = translate(tree.var, null);
510 Type iterableType = tree.expr.type;
511 tree.expr = translate(tree.expr, erasure(tree.expr.type));
512 if (types.elemtype(tree.expr.type) == null)
513 tree.expr.type = iterableType; // preserve type for Lower
514 tree.body = translate(tree.body);
515 result = tree;
516 }
517
518 public void visitSwitch(JCSwitch tree) {
519 Type selsuper = types.supertype(tree.selector.type);
520 boolean enumSwitch = selsuper != null &&
521 selsuper.tsym == syms.enumSym;
522 Type target = enumSwitch ? erasure(tree.selector.type) : syms.intType;
523 tree.selector = translate(tree.selector, target);
524 tree.cases = translateCases(tree.cases);
525 result = tree;
526 }
527
528 public void visitCase(JCCase tree) {
529 tree.pat = translate(tree.pat, null);
530 tree.stats = translate(tree.stats);
531 result = tree;
532 }
533
534 public void visitSynchronized(JCSynchronized tree) {
535 tree.lock = translate(tree.lock, erasure(tree.lock.type));
536 tree.body = translate(tree.body);
537 result = tree;
538 }
539
540 public void visitTry(JCTry tree) {
541 tree.resources = translate(tree.resources, syms.autoCloseableType);
542 tree.body = translate(tree.body);
543 tree.catchers = translateCatchers(tree.catchers);
544 tree.finalizer = translate(tree.finalizer);
545 result = tree;
546 }
547
548 public void visitConditional(JCConditional tree) {
549 tree.cond = translate(tree.cond, syms.booleanType);
550 tree.truepart = translate(tree.truepart, erasure(tree.type));
551 tree.falsepart = translate(tree.falsepart, erasure(tree.type));
552 tree.type = erasure(tree.type);
553 result = retype(tree, tree.type, pt);
554 }
555
556 public void visitIf(JCIf tree) {
557 tree.cond = translate(tree.cond, syms.booleanType);
558 tree.thenpart = translate(tree.thenpart);
559 tree.elsepart = translate(tree.elsepart);
560 result = tree;
561 }
562
563 public void visitExec(JCExpressionStatement tree) {
564 tree.expr = translate(tree.expr, null);
565 result = tree;
566 }
567
568 public void visitReturn(JCReturn tree) {
569 tree.expr = translate(tree.expr, currentMethod.sym.erasure(types).getReturnType());
570 result = tree;
571 }
572
573 public void visitThrow(JCThrow tree) {
574 tree.expr = translate(tree.expr, erasure(tree.expr.type));
575 result = tree;
576 }
577
578 public void visitAssert(JCAssert tree) {
579 tree.cond = translate(tree.cond, syms.booleanType);
580 if (tree.detail != null)
581 tree.detail = translate(tree.detail, erasure(tree.detail.type));
582 result = tree;
583 }
584
585 public void visitApply(JCMethodInvocation tree) {
586 tree.meth = translate(tree.meth, null);
587 Symbol meth = TreeInfo.symbol(tree.meth);
588 Type mt = meth.erasure(types);
589 List<Type> argtypes = mt.getParameterTypes();
590 if (allowEnums &&
591 meth.name==names.init &&
592 meth.owner == syms.enumSym)
593 argtypes = argtypes.tail.tail;
594 if (tree.varargsElement != null)
595 tree.varargsElement = types.erasure(tree.varargsElement);
596 else
597 Assert.check(tree.args.length() == argtypes.length());
598 tree.args = translateArgs(tree.args, argtypes, tree.varargsElement);
599
600 // Insert casts of method invocation results as needed.
601 result = retype(tree, mt.getReturnType(), pt);
602 }
603
604 public void visitNewClass(JCNewClass tree) {
605 if (tree.encl != null)
606 tree.encl = translate(tree.encl, erasure(tree.encl.type));
607 tree.clazz = translate(tree.clazz, null);
608 if (tree.varargsElement != null)
609 tree.varargsElement = types.erasure(tree.varargsElement);
610 tree.args = translateArgs(
611 tree.args, tree.constructor.erasure(types).getParameterTypes(), tree.varargsElement);
612 tree.def = translate(tree.def, null);
613 tree.type = erasure(tree.type);
614 result = tree;
615 }
616
617 public void visitNewArray(JCNewArray tree) {
618 tree.elemtype = translate(tree.elemtype, null);
619 translate(tree.dims, syms.intType);
620 if (tree.type != null) {
621 tree.elems = translate(tree.elems, erasure(types.elemtype(tree.type)));
622 tree.type = erasure(tree.type);
623 } else {
624 tree.elems = translate(tree.elems, null);
625 }
626
627 result = tree;
628 }
629
630 public void visitParens(JCParens tree) {
631 tree.expr = translate(tree.expr, pt);
632 tree.type = erasure(tree.type);
633 result = tree;
634 }
635
636 public void visitAssign(JCAssign tree) {
637 tree.lhs = translate(tree.lhs, null);
638 tree.rhs = translate(tree.rhs, erasure(tree.lhs.type));
639 tree.type = erasure(tree.type);
640 result = tree;
641 }
642
643 public void visitAssignop(JCAssignOp tree) {
644 tree.lhs = translate(tree.lhs, null);
645 tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head);
646 tree.type = erasure(tree.type);
647 result = tree;
648 }
649
650 public void visitUnary(JCUnary tree) {
651 tree.arg = translate(tree.arg, tree.operator.type.getParameterTypes().head);
652 result = tree;
653 }
654
655 public void visitBinary(JCBinary tree) {
656 tree.lhs = translate(tree.lhs, tree.operator.type.getParameterTypes().head);
657 tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head);
658 result = tree;
659 }
660
661 public void visitTypeCast(JCTypeCast tree) {
662 tree.clazz = translate(tree.clazz, null);
663 tree.type = erasure(tree.type);
664 tree.expr = translate(tree.expr, tree.type);
665 result = tree;
666 }
667
668 public void visitTypeTest(JCInstanceOf tree) {
669 tree.expr = translate(tree.expr, null);
670 tree.clazz = translate(tree.clazz, null);
671 result = tree;
672 }
673
674 public void visitIndexed(JCArrayAccess tree) {
675 tree.indexed = translate(tree.indexed, erasure(tree.indexed.type));
676 tree.index = translate(tree.index, syms.intType);
677
678 // Insert casts of indexed expressions as needed.
679 result = retype(tree, types.elemtype(tree.indexed.type), pt);
680 }
681
682 // There ought to be nothing to rewrite here;
683 // we don't generate code.
684 public void visitAnnotation(JCAnnotation tree) {
685 result = tree;
686 }
687
688 public void visitIdent(JCIdent tree) {
689 Type et = tree.sym.erasure(types);
690
691 // Map type variables to their bounds.
692 if (tree.sym.kind == TYP && tree.sym.type.tag == TYPEVAR) {
693 result = make.at(tree.pos).Type(et);
694 } else
695 // Map constants expressions to themselves.
696 if (tree.type.constValue() != null) {
697 result = tree;
698 }
699 // Insert casts of variable uses as needed.
700 else if (tree.sym.kind == VAR) {
701 result = retype(tree, et, pt);
702 }
703 else {
704 tree.type = erasure(tree.type);
705 result = tree;
706 }
707 }
708
709 public void visitSelect(JCFieldAccess tree) {
710 Type t = tree.selected.type;
711 while (t.tag == TYPEVAR)
712 t = t.getUpperBound();
713 if (t.isCompound()) {
714 if ((tree.sym.flags() & IPROXY) != 0) {
715 tree.sym = ((MethodSymbol)tree.sym).
716 implemented((TypeSymbol)tree.sym.owner, types);
717 }
718 tree.selected = coerce(
719 translate(tree.selected, erasure(tree.selected.type)),
720 erasure(tree.sym.owner.type));
721 } else
722 tree.selected = translate(tree.selected, erasure(t));
723
724 // Map constants expressions to themselves.
725 if (tree.type.constValue() != null) {
726 result = tree;
727 }
728 // Insert casts of variable uses as needed.
729 else if (tree.sym.kind == VAR) {
730 result = retype(tree, tree.sym.erasure(types), pt);
731 }
732 else {
733 tree.type = erasure(tree.type);
734 result = tree;
735 }
736 }
737
738 public void visitTypeArray(JCArrayTypeTree tree) {
739 tree.elemtype = translate(tree.elemtype, null);
740 tree.type = erasure(tree.type);
741 result = tree;
742 }
743
744 /** Visitor method for parameterized types.
745 */
746 public void visitTypeApply(JCTypeApply tree) {
747 JCTree clazz = translate(tree.clazz, null);
748 result = clazz;
749 }
750
751 /**************************************************************************
752 * utility methods
753 *************************************************************************/
754
755 private Type erasure(Type t) {
756 return types.erasure(t);
757 }
758
759 private boolean boundsRestricted(ClassSymbol c) {
760 Type st = types.supertype(c.type);
761 if (st.isParameterized()) {
762 List<Type> actuals = st.allparams();
763 List<Type> formals = st.tsym.type.allparams();
764 while (!actuals.isEmpty() && !formals.isEmpty()) {
765 Type actual = actuals.head;
766 Type formal = formals.head;
767
768 if (!types.isSameType(types.erasure(actual),
769 types.erasure(formal)))
770 return true;
771
772 actuals = actuals.tail;
773 formals = formals.tail;
774 }
775 }
776 return false;
777 }
778
779 private List<JCTree> addOverrideBridgesIfNeeded(DiagnosticPosition pos,
780 final ClassSymbol c) {
781 ListBuffer<JCTree> buf = ListBuffer.lb();
782 if (c.isInterface() || !boundsRestricted(c))
783 return buf.toList();
784 Type t = types.supertype(c.type);
785 Scope s = t.tsym.members();
786 if (s.elems != null) {
787 for (Symbol sym : s.getElements(new NeedsOverridBridgeFilter(c))) {
788
789 MethodSymbol m = (MethodSymbol)sym;
790 MethodSymbol member = (MethodSymbol)m.asMemberOf(c.type, types);
791 MethodSymbol impl = m.implementation(c, types, false);
792
793 if ((impl == null || impl.owner != c) &&
794 !types.isSameType(member.erasure(types), m.erasure(types))) {
795 addOverrideBridges(pos, m, member, c, buf);
796 }
797 }
798 }
799 return buf.toList();
800 }
801 // where
802 class NeedsOverridBridgeFilter implements Filter<Symbol> {
803
804 ClassSymbol c;
805
806 NeedsOverridBridgeFilter(ClassSymbol c) {
807 this.c = c;
808 }
809 public boolean accepts(Symbol s) {
810 return s.kind == MTH &&
811 !s.isConstructor() &&
812 s.isInheritedIn(c, types) &&
813 (s.flags() & FINAL) == 0 &&
814 (s.flags() & (SYNTHETIC | OVERRIDE_BRIDGE)) != SYNTHETIC;
815 }
816 }
817
818 private void addOverrideBridges(DiagnosticPosition pos,
819 MethodSymbol impl,
820 MethodSymbol member,
821 ClassSymbol c,
822 ListBuffer<JCTree> bridges) {
823 Type implErasure = impl.erasure(types);
824 long flags = (impl.flags() & AccessFlags) | SYNTHETIC | BRIDGE | OVERRIDE_BRIDGE;
825 member = new MethodSymbol(flags, member.name, member.type, c);
826 JCMethodDecl md = make.MethodDef(member, null);
827 JCExpression receiver = make.Super(types.supertype(c.type).tsym.erasure(types), c);
828 Type calltype = erasure(impl.type.getReturnType());
829 JCExpression call =
830 make.Apply(null,
831 make.Select(receiver, impl).setType(calltype),
832 translateArgs(make.Idents(md.params),
833 implErasure.getParameterTypes(), null))
834 .setType(calltype);
835 JCStatement stat = (member.getReturnType().tag == VOID)
836 ? make.Exec(call)
837 : make.Return(coerce(call, member.erasure(types).getReturnType()));
838 md.body = make.Block(0, List.of(stat));
839 c.members().enter(member);
840 bridges.append(md);
841 }
842
843 /**************************************************************************
844 * main method
845 *************************************************************************/
846
847 private Env<AttrContext> env;
848
849 void translateClass(ClassSymbol c) {
850 Type st = types.supertype(c.type);
851
852 // process superclass before derived
853 if (st.tag == CLASS)
854 translateClass((ClassSymbol)st.tsym);
855
856 Env<AttrContext> myEnv = enter.typeEnvs.remove(c);
857 if (myEnv == null)
858 return;
859 Env<AttrContext> oldEnv = env;
860 try {
861 env = myEnv;
862 // class has not been translated yet
863
864 TreeMaker savedMake = make;
865 Type savedPt = pt;
866 make = make.forToplevel(env.toplevel);
867 pt = null;
868 try {
869 JCClassDecl tree = (JCClassDecl) env.tree;
870 tree.typarams = List.nil();
871 super.visitClassDef(tree);
872 make.at(tree.pos);
873 if (addBridges) {
874 ListBuffer<JCTree> bridges = new ListBuffer<JCTree>();
875 if (false) //see CR: 6996415
876 bridges.appendList(addOverrideBridgesIfNeeded(tree, c));
877 if ((tree.sym.flags() & INTERFACE) == 0)
878 addBridges(tree.pos(), tree.sym, bridges);
879 tree.defs = bridges.toList().prependList(tree.defs);
880 }
881 tree.type = erasure(tree.type);
882 } finally {
883 make = savedMake;
884 pt = savedPt;
885 }
886 } finally {
887 env = oldEnv;
888 }
889 }
890
891 /** Translate a toplevel class definition.
892 * @param cdef The definition to be translated.
893 */
894 public JCTree translateTopLevelClass(JCTree cdef, TreeMaker make) {
895 // note that this method does NOT support recursion.
896 this.make = make;
897 pt = null;
898 return translate(cdef, null);
899 }
900 }