1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)dependencies.cpp 1.18 08/02/29 12:46:18 JVM"
3 #endif
4 /*
5 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_dependencies.cpp.incl"
30
31
32 #ifdef ASSERT
33 static bool must_be_in_vm() {
34 Thread* thread = Thread::current();
35 if (thread->is_Java_thread())
36 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
37 else
38 return true; //something like this: thread->is_VM_thread();
39 }
40 #endif //ASSERT
41
42 void Dependencies::initialize(ciEnv* env) {
43 Arena* arena = env->arena();
44 _oop_recorder = env->oop_recorder();
45 _log = env->log();
46 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
47 DEBUG_ONLY(_deps[end_marker] = NULL);
48 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
49 _deps[i] = new(arena) GrowableArray<ciObject*>(arena, 10, 0, 0);
50 }
51 _content_bytes = NULL;
52 _size_in_bytes = (size_t)-1;
53
54 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
55 }
56
57 void Dependencies::assert_evol_method(ciMethod* m) {
58 assert_common_1(evol_method, m);
59 }
60
61 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
62 if (ctxk->is_array_klass()) {
63 // As a special case, support this assertion on an array type,
64 // which reduces to an assertion on its element type.
65 // Note that this cannot be done with assertions that
66 // relate to concreteness or abstractness.
67 ciType* elemt = ctxk->as_array_klass()->base_element_type();
68 if (!elemt->is_instance_klass()) return; // Ex: int[][]
69 ctxk = elemt->as_instance_klass();
70 //if (ctxk->is_final()) return; // Ex: String[][]
71 }
72 check_ctxk(ctxk);
73 assert_common_1(leaf_type, ctxk);
74 }
75
76 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
77 check_ctxk_abstract(ctxk);
78 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
79 }
80
81 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
82 check_ctxk_abstract(ctxk);
83 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
84 }
85
86 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
87 check_ctxk_concrete(ctxk);
88 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
89 }
90
91 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
92 check_ctxk(ctxk);
93 assert_common_2(unique_concrete_method, ctxk, uniqm);
94 }
95
96 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
97 check_ctxk(ctxk);
98 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
99 }
100
101 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
102 check_ctxk(ctxk);
103 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
104 }
105
106 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
107 check_ctxk(ctxk);
108 assert_common_1(no_finalizable_subclasses, ctxk);
109 }
110
111 // Helper function. If we are adding a new dep. under ctxk2,
112 // try to find an old dep. under a broader* ctxk1. If there is
113 //
114 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciObject*>* deps,
115 int ctxk_i, ciKlass* ctxk2) {
116 ciKlass* ctxk1 = deps->at(ctxk_i)->as_klass();
117 if (ctxk2->is_subtype_of(ctxk1)) {
118 return true; // success, and no need to change
119 } else if (ctxk1->is_subtype_of(ctxk2)) {
120 // new context class fully subsumes previous one
121 deps->at_put(ctxk_i, ctxk2);
122 return true;
123 } else {
124 return false;
125 }
126 }
127
128 void Dependencies::assert_common_1(Dependencies::DepType dept, ciObject* x) {
129 assert(dep_args(dept) == 1, "sanity");
130 log_dependency(dept, x);
131 GrowableArray<ciObject*>* deps = _deps[dept];
132
133 // see if the same (or a similar) dep is already recorded
134 if (note_dep_seen(dept, x)) {
135 assert(deps->find(x) >= 0, "sanity");
136 } else {
137 deps->append(x);
138 }
139 }
140
141 void Dependencies::assert_common_2(Dependencies::DepType dept,
142 ciKlass* ctxk, ciObject* x) {
143 assert(dep_context_arg(dept) == 0, "sanity");
144 assert(dep_args(dept) == 2, "sanity");
145 log_dependency(dept, ctxk, x);
146 GrowableArray<ciObject*>* deps = _deps[dept];
147
148 // see if the same (or a similar) dep is already recorded
149 if (note_dep_seen(dept, x)) {
150 // look in this bucket for redundant assertions
151 const int stride = 2;
152 for (int i = deps->length(); (i -= stride) >= 0; ) {
153 ciObject* x1 = deps->at(i+1);
154 if (x == x1) { // same subject; check the context
155 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
156 return;
157 }
158 }
159 }
160 }
161
162 // append the assertion in the correct bucket:
163 deps->append(ctxk);
164 deps->append(x);
165 }
166
167 void Dependencies::assert_common_3(Dependencies::DepType dept,
168 ciKlass* ctxk, ciObject* x, ciObject* x2) {
169 assert(dep_context_arg(dept) == 0, "sanity");
170 assert(dep_args(dept) == 3, "sanity");
171 log_dependency(dept, ctxk, x, x2);
172 GrowableArray<ciObject*>* deps = _deps[dept];
173
174 // try to normalize an unordered pair:
175 bool swap = false;
176 switch (dept) {
177 case abstract_with_exclusive_concrete_subtypes_2:
178 swap = (x->ident() > x2->ident() && x != ctxk);
179 break;
180 case exclusive_concrete_methods_2:
181 swap = (x->ident() > x2->ident() && x->as_method()->holder() != ctxk);
182 break;
183 }
184 if (swap) { ciObject* t = x; x = x2; x2 = t; }
185
186 // see if the same (or a similar) dep is already recorded
187 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
188 // look in this bucket for redundant assertions
189 const int stride = 3;
190 for (int i = deps->length(); (i -= stride) >= 0; ) {
191 ciObject* y = deps->at(i+1);
192 ciObject* y2 = deps->at(i+2);
193 if (x == y && x2 == y2) { // same subjects; check the context
194 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
195 return;
196 }
197 }
198 }
199 }
200 // append the assertion in the correct bucket:
201 deps->append(ctxk);
202 deps->append(x);
203 deps->append(x2);
204 }
205
206 /// Support for encoding dependencies into an nmethod:
207
208 void Dependencies::copy_to(nmethod* nm) {
209 address beg = nm->dependencies_begin();
210 address end = nm->dependencies_end();
211 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
212 Copy::disjoint_words((HeapWord*) content_bytes(),
213 (HeapWord*) beg,
214 size_in_bytes() / sizeof(HeapWord));
215 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
216 }
217
218 static int sort_dep(ciObject** p1, ciObject** p2, int narg) {
219 for (int i = 0; i < narg; i++) {
220 int diff = p1[i]->ident() - p2[i]->ident();
221 if (diff != 0) return diff;
222 }
223 return 0;
224 }
225 static int sort_dep_arg_1(ciObject** p1, ciObject** p2)
226 { return sort_dep(p1, p2, 1); }
227 static int sort_dep_arg_2(ciObject** p1, ciObject** p2)
228 { return sort_dep(p1, p2, 2); }
229 static int sort_dep_arg_3(ciObject** p1, ciObject** p2)
230 { return sort_dep(p1, p2, 3); }
231
232 void Dependencies::sort_all_deps() {
233 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
234 DepType dept = (DepType)deptv;
235 GrowableArray<ciObject*>* deps = _deps[dept];
236 if (deps->length() <= 1) continue;
237 switch (dep_args(dept)) {
238 case 1: deps->sort(sort_dep_arg_1, 1); break;
239 case 2: deps->sort(sort_dep_arg_2, 2); break;
240 case 3: deps->sort(sort_dep_arg_3, 3); break;
241 default: ShouldNotReachHere();
242 }
243 }
244 }
245
246 size_t Dependencies::estimate_size_in_bytes() {
247 size_t est_size = 100;
248 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
249 DepType dept = (DepType)deptv;
250 GrowableArray<ciObject*>* deps = _deps[dept];
251 est_size += deps->length()*2; // tags and argument(s)
252 }
253 return est_size;
254 }
255
256 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciObject* x) {
257 switch (dept) {
258 case abstract_with_exclusive_concrete_subtypes_2:
259 return x->as_klass();
260 case unique_concrete_method:
261 case exclusive_concrete_methods_2:
262 return x->as_method()->holder();
263 }
264 return NULL; // let NULL be NULL
265 }
266
267 klassOop Dependencies::ctxk_encoded_as_null(DepType dept, oop x) {
268 assert(must_be_in_vm(), "raw oops here");
269 switch (dept) {
270 case abstract_with_exclusive_concrete_subtypes_2:
271 assert(x->is_klass(), "sanity");
272 return (klassOop) x;
273 case unique_concrete_method:
274 case exclusive_concrete_methods_2:
275 assert(x->is_method(), "sanity");
276 return ((methodOop)x)->method_holder();
277 }
278 return NULL; // let NULL be NULL
279 }
280
281 void Dependencies::encode_content_bytes() {
282 sort_all_deps();
283
284 // cast is safe, no deps can overflow INT_MAX
285 CompressedWriteStream bytes((int)estimate_size_in_bytes());
286
287 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
288 DepType dept = (DepType)deptv;
289 GrowableArray<ciObject*>* deps = _deps[dept];
290 if (deps->length() == 0) continue;
291 int stride = dep_args(dept);
292 int ctxkj = dep_context_arg(dept); // -1 if no context arg
293 assert(stride > 0, "sanity");
294 for (int i = 0; i < deps->length(); i += stride) {
295 jbyte code_byte = (jbyte)dept;
296 int skipj = -1;
297 if (ctxkj >= 0 && ctxkj+1 < stride) {
298 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_klass();
299 ciObject* x = deps->at(i+ctxkj+1); // following argument
300 if (ctxk == ctxk_encoded_as_null(dept, x)) {
301 skipj = ctxkj; // we win: maybe one less oop to keep track of
302 code_byte |= default_context_type_bit;
303 }
304 }
305 bytes.write_byte(code_byte);
306 for (int j = 0; j < stride; j++) {
307 if (j == skipj) continue;
308 bytes.write_int(_oop_recorder->find_index(deps->at(i+j)->encoding()));
309 }
310 }
311 }
312
313 // write a sentinel byte to mark the end
314 bytes.write_byte(end_marker);
315
316 // round it out to a word boundary
317 while (bytes.position() % sizeof(HeapWord) != 0) {
318 bytes.write_byte(end_marker);
319 }
320
321 // check whether the dept byte encoding really works
322 assert((jbyte)default_context_type_bit != 0, "byte overflow");
323
324 _content_bytes = bytes.buffer();
325 _size_in_bytes = bytes.position();
326 }
327
328
329 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
330 "end_marker",
331 "evol_method",
332 "leaf_type",
333 "abstract_with_unique_concrete_subtype",
334 "abstract_with_no_concrete_subtype",
335 "concrete_with_no_concrete_subtype",
336 "unique_concrete_method",
337 "abstract_with_exclusive_concrete_subtypes_2",
338 "exclusive_concrete_methods_2",
339 "no_finalizable_subclasses"
340 };
341
342 int Dependencies::_dep_args[TYPE_LIMIT] = {
343 -1,// end_marker
344 1, // evol_method m
345 1, // leaf_type ctxk
346 2, // abstract_with_unique_concrete_subtype ctxk, k
347 1, // abstract_with_no_concrete_subtype ctxk
348 1, // concrete_with_no_concrete_subtype ctxk
349 2, // unique_concrete_method ctxk, m
350 3, // unique_concrete_subtypes_2 ctxk, k1, k2
351 3, // unique_concrete_methods_2 ctxk, m1, m2
352 1 // no_finalizable_subclasses ctxk
353 };
354
355 const char* Dependencies::dep_name(Dependencies::DepType dept) {
356 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
357 return _dep_name[dept];
358 }
359
360 int Dependencies::dep_args(Dependencies::DepType dept) {
361 if (!dept_in_mask(dept, all_types)) return -1;
362 return _dep_args[dept];
363 }
364
365 // for the sake of the compiler log, print out current dependencies:
366 void Dependencies::log_all_dependencies() {
367 if (log() == NULL) return;
368 ciObject* args[max_arg_count];
369 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
370 DepType dept = (DepType)deptv;
371 GrowableArray<ciObject*>* deps = _deps[dept];
372 if (deps->length() == 0) continue;
373 int stride = dep_args(dept);
374 for (int i = 0; i < deps->length(); i += stride) {
375 for (int j = 0; j < stride; j++) {
376 // flush out the identities before printing
377 args[j] = deps->at(i+j);
378 }
379 write_dependency_to(log(), dept, stride, args);
380 }
381 }
382 }
383
384 void Dependencies::write_dependency_to(CompileLog* log,
385 DepType dept,
386 int nargs, oop args[],
387 klassOop witness) {
388 if (log == NULL) {
389 return;
390 }
391 ciEnv* env = ciEnv::current();
392 ciObject* ciargs[max_arg_count];
393 assert(nargs <= max_arg_count, "oob");
394 for (int j = 0; j < nargs; j++) {
395 ciargs[j] = env->get_object(args[j]);
396 }
397 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
398 }
399
400 void Dependencies::write_dependency_to(CompileLog* log,
401 DepType dept,
402 int nargs, ciObject* args[],
403 klassOop witness) {
404 if (log == NULL) return;
405 assert(nargs <= max_arg_count, "oob");
406 int argids[max_arg_count];
407 int ctxkj = dep_context_arg(dept); // -1 if no context arg
408 int j;
409 for (j = 0; j < nargs; j++) {
410 argids[j] = log->identify(args[j]);
411 }
412 if (witness != NULL) {
413 log->begin_elem("dependency_failed");
414 } else {
415 log->begin_elem("dependency");
416 }
417 log->print(" type='%s'", dep_name(dept));
418 if (ctxkj >= 0) {
419 log->print(" ctxk='%d'", argids[ctxkj]);
420 }
421 // write remaining arguments, if any.
422 for (j = 0; j < nargs; j++) {
423 if (j == ctxkj) continue; // already logged
424 if (j == 1) {
425 log->print( " x='%d'", argids[j]);
426 } else {
427 log->print(" x%d='%d'", j, argids[j]);
428 }
429 }
430 if (witness != NULL) {
431 log->object("witness", witness);
432 log->stamp();
433 }
434 log->end_elem();
435 }
436
437 void Dependencies::write_dependency_to(xmlStream* xtty,
438 DepType dept,
439 int nargs, oop args[],
440 klassOop witness) {
441 if (xtty == NULL) return;
442 ttyLocker ttyl;
443 int ctxkj = dep_context_arg(dept); // -1 if no context arg
444 if (witness != NULL) {
445 xtty->begin_elem("dependency_failed");
446 } else {
447 xtty->begin_elem("dependency");
448 }
449 xtty->print(" type='%s'", dep_name(dept));
450 if (ctxkj >= 0) {
451 xtty->object("ctxk", args[ctxkj]);
452 }
453 // write remaining arguments, if any.
454 for (int j = 0; j < nargs; j++) {
455 if (j == ctxkj) continue; // already logged
456 if (j == 1) {
457 xtty->object("x", args[j]);
458 } else {
459 char xn[10]; sprintf(xn, "x%d", j);
460 xtty->object(xn, args[j]);
461 }
462 }
463 if (witness != NULL) {
464 xtty->object("witness", witness);
465 xtty->stamp();
466 }
467 xtty->end_elem();
468 }
469
470 void Dependencies::print_dependency(DepType dept, int nargs, oop args[],
471 klassOop witness) {
472 ResourceMark rm;
473 ttyLocker ttyl; // keep the following output all in one block
474 tty->print_cr("%s of type %s",
475 (witness == NULL)? "Dependency": "Failed dependency",
476 dep_name(dept));
477 // print arguments
478 int ctxkj = dep_context_arg(dept); // -1 if no context arg
479 for (int j = 0; j < nargs; j++) {
480 oop arg = args[j];
481 bool put_star = false;
482 if (arg == NULL) continue;
483 const char* what;
484 if (j == ctxkj) {
485 what = "context";
486 put_star = !Dependencies::is_concrete_klass((klassOop)arg);
487 } else if (arg->is_method()) {
488 what = "method ";
489 put_star = !Dependencies::is_concrete_method((methodOop)arg);
490 } else if (arg->is_klass()) {
491 what = "class ";
492 } else {
493 what = "object ";
494 }
495 tty->print(" %s = %s", what, (put_star? "*": ""));
496 if (arg->is_klass())
497 tty->print("%s", Klass::cast((klassOop)arg)->external_name());
498 else
499 arg->print_value();
500 tty->cr();
501 }
502 if (witness != NULL) {
503 bool put_star = !Dependencies::is_concrete_klass(witness);
504 tty->print_cr(" witness = %s%s",
505 (put_star? "*": ""),
506 Klass::cast(witness)->external_name());
507 }
508 }
509
510 void Dependencies::DepStream::log_dependency(klassOop witness) {
511 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
512 int nargs = argument_count();
513 oop args[max_arg_count];
514 for (int j = 0; j < nargs; j++) {
515 args[j] = argument(j);
516 }
517 if (_deps != NULL && _deps->log() != NULL) {
518 Dependencies::write_dependency_to(_deps->log(),
519 type(), nargs, args, witness);
520 } else {
521 Dependencies::write_dependency_to(xtty,
522 type(), nargs, args, witness);
523 }
524 }
525
526 void Dependencies::DepStream::print_dependency(klassOop witness, bool verbose) {
527 int nargs = argument_count();
528 oop args[max_arg_count];
529 for (int j = 0; j < nargs; j++) {
530 args[j] = argument(j);
531 }
532 Dependencies::print_dependency(type(), nargs, args, witness);
533 if (verbose) {
534 if (_code != NULL) {
535 tty->print(" code: ");
536 _code->print_value_on(tty);
537 tty->cr();
538 }
539 }
540 }
541
542
543 /// Dependency stream support (decodes dependencies from an nmethod):
544
545 #ifdef ASSERT
546 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
547 assert(must_be_in_vm(), "raw oops here");
548 _byte_limit = byte_limit;
549 _type = (DepType)(end_marker-1); // defeat "already at end" assert
550 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
551 }
552 #endif //ASSERT
553
554 bool Dependencies::DepStream::next() {
555 assert(_type != end_marker, "already at end");
556 if (_bytes.position() == 0 && _code != NULL
557 && _code->dependencies_size() == 0) {
558 // Method has no dependencies at all.
559 return false;
560 }
561 int code_byte = (_bytes.read_byte() & 0xFF);
562 if (code_byte == end_marker) {
563 DEBUG_ONLY(_type = end_marker);
564 return false;
565 } else {
566 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
567 code_byte -= ctxk_bit;
568 DepType dept = (DepType)code_byte;
569 _type = dept;
570 guarantee((dept - FIRST_TYPE) < (TYPE_LIMIT - FIRST_TYPE),
571 "bad dependency type tag");
572 int stride = _dep_args[dept];
573 assert(stride == dep_args(dept), "sanity");
574 int skipj = -1;
575 if (ctxk_bit != 0) {
576 skipj = 0; // currently the only context argument is at zero
577 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
578 }
579 for (int j = 0; j < stride; j++) {
580 _xi[j] = (j == skipj)? 0: _bytes.read_int();
581 }
582 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
583 return true;
584 }
585 }
586
587 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
588 return (_code != NULL)
589 ? _code->oop_at(i)
590 : JNIHandles::resolve(_deps->oop_recorder()->handle_at(i));
591 }
592
593 oop Dependencies::DepStream::argument(int i) {
594 return recorded_oop_at(argument_index(i));
595 }
596
597 klassOop Dependencies::DepStream::context_type() {
598 assert(must_be_in_vm(), "raw oops here");
599 int ctxkj = dep_context_arg(_type); // -1 if no context arg
600 if (ctxkj < 0) {
601 return NULL; // for example, evol_method
602 } else {
603 oop k = recorded_oop_at(_xi[ctxkj]);
604 if (k != NULL) { // context type was not compressed away
605 assert(k->is_klass(), "type check");
606 return (klassOop) k;
607 } else { // recompute "default" context type
608 return ctxk_encoded_as_null(_type, recorded_oop_at(_xi[ctxkj+1]));
609 }
610 }
611 }
612
613 /// Checking dependencies:
614
615 // This hierarchy walker inspects subtypes of a given type,
616 // trying to find a "bad" class which breaks a dependency.
617 // Such a class is called a "witness" to the broken dependency.
618 // While searching around, we ignore "participants", which
619 // are already known to the dependency.
620 class ClassHierarchyWalker {
621 public:
622 enum { PARTICIPANT_LIMIT = 3 };
623
624 private:
625 // optional method descriptor to check for:
626 symbolOop _name;
627 symbolOop _signature;
628
629 // special classes which are not allowed to be witnesses:
630 klassOop _participants[PARTICIPANT_LIMIT+1];
631 int _num_participants;
632
633 // cache of method lookups
634 methodOop _found_methods[PARTICIPANT_LIMIT+1];
635
636 // if non-zero, tells how many witnesses to convert to participants
637 int _record_witnesses;
638
639 void initialize(klassOop participant) {
640 _record_witnesses = 0;
641 _participants[0] = participant;
642 _found_methods[0] = NULL;
643 _num_participants = 0;
644 if (participant != NULL) {
645 // Terminating NULL.
646 _participants[1] = NULL;
647 _found_methods[1] = NULL;
648 _num_participants = 1;
649 }
650 }
651
652 void initialize_from_method(methodOop m) {
653 assert(m != NULL && m->is_method(), "sanity");
654 _name = m->name();
655 _signature = m->signature();
656 }
657
658 public:
659 // The walker is initialized to recognize certain methods and/or types
660 // as friendly participants.
661 ClassHierarchyWalker(klassOop participant, methodOop m) {
662 initialize_from_method(m);
663 initialize(participant);
664 }
665 ClassHierarchyWalker(methodOop m) {
666 initialize_from_method(m);
667 initialize(NULL);
668 }
669 ClassHierarchyWalker(klassOop participant = NULL) {
670 _name = NULL;
671 _signature = NULL;
672 initialize(participant);
673 }
674
675 // This is common code for two searches: One for concrete subtypes,
676 // the other for concrete method implementations and overrides.
677 bool doing_subtype_search() {
678 return _name == NULL;
679 }
680
681 int num_participants() { return _num_participants; }
682 klassOop participant(int n) {
683 assert((uint)n <= (uint)_num_participants, "oob");
684 return _participants[n];
685 }
686
687 // Note: If n==num_participants, returns NULL.
688 methodOop found_method(int n) {
689 assert((uint)n <= (uint)_num_participants, "oob");
690 methodOop fm = _found_methods[n];
691 assert(n == _num_participants || fm != NULL, "proper usage");
692 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
693 return fm;
694 }
695
696 #ifdef ASSERT
697 // Assert that m is inherited into ctxk, without intervening overrides.
698 // (May return true even if this is not true, in corner cases where we punt.)
699 bool check_method_context(klassOop ctxk, methodOop m) {
700 if (m->method_holder() == ctxk)
701 return true; // Quick win.
702 if (m->is_private())
703 return false; // Quick lose. Should not happen.
704 if (!(m->is_public() || m->is_protected()))
705 // The override story is complex when packages get involved.
706 return true; // Must punt the assertion to true.
707 Klass* k = Klass::cast(ctxk);
708 methodOop lm = k->lookup_method(m->name(), m->signature());
709 if (lm == NULL && k->oop_is_instance()) {
710 // It might be an abstract interface method, devoid of mirandas.
711 lm = ((instanceKlass*)k)->lookup_method_in_all_interfaces(m->name(),
712 m->signature());
713 }
714 if (lm == m)
715 // Method m is inherited into ctxk.
716 return true;
717 if (lm != NULL) {
718 if (!(lm->is_public() || lm->is_protected()))
719 // Method is [package-]private, so the override story is complex.
720 return true; // Must punt the assertion to true.
721 if ( !Dependencies::is_concrete_method(lm)
722 && !Dependencies::is_concrete_method(m)
723 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder()))
724 // Method m is overridden by lm, but both are non-concrete.
725 return true;
726 }
727 ResourceMark rm;
728 tty->print_cr("Dependency method not found in the associated context:");
729 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name());
730 tty->print( " method = "); m->print_short_name(tty); tty->cr();
731 if (lm != NULL) {
732 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
733 }
734 return false;
735 }
736 #endif
737
738 void add_participant(klassOop participant) {
739 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
740 int np = _num_participants++;
741 _participants[np] = participant;
742 _participants[np+1] = NULL;
743 _found_methods[np+1] = NULL;
744 }
745
746 void record_witnesses(int add) {
747 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
748 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
749 _record_witnesses = add;
750 }
751
752 bool is_witness(klassOop k) {
753 if (doing_subtype_search()) {
754 return Dependencies::is_concrete_klass(k);
755 } else {
756 methodOop m = instanceKlass::cast(k)->find_method(_name, _signature);
757 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
758 _found_methods[_num_participants] = m;
759 // Note: If add_participant(k) is called,
760 // the method m will already be memoized for it.
761 return true;
762 }
763 }
764
765 bool is_participant(klassOop k) {
766 if (k == _participants[0]) {
767 return true;
768 } else if (_num_participants <= 1) {
769 return false;
770 } else {
771 return in_list(k, &_participants[1]);
772 }
773 }
774 bool ignore_witness(klassOop witness) {
775 if (_record_witnesses == 0) {
776 return false;
777 } else {
778 --_record_witnesses;
779 add_participant(witness);
780 return true;
781 }
782 }
783 static bool in_list(klassOop x, klassOop* list) {
784 for (int i = 0; ; i++) {
785 klassOop y = list[i];
786 if (y == NULL) break;
787 if (y == x) return true;
788 }
789 return false; // not in list
790 }
791
792 private:
793 // the actual search method:
794 klassOop find_witness_anywhere(klassOop context_type,
795 bool participants_hide_witnesses,
796 bool top_level_call = true);
797 // the spot-checking version:
798 klassOop find_witness_in(DepChange& changes,
799 klassOop context_type,
800 bool participants_hide_witnesses);
801 public:
802 klassOop find_witness_subtype(klassOop context_type, DepChange* changes = NULL) {
803 assert(doing_subtype_search(), "must set up a subtype search");
804 // When looking for unexpected concrete types,
805 // do not look beneath expected ones.
806 const bool participants_hide_witnesses = true;
807 // CX > CC > C' is OK, even if C' is new.
808 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
809 if (changes != NULL) {
810 return find_witness_in(*changes, context_type, participants_hide_witnesses);
811 } else {
812 return find_witness_anywhere(context_type, participants_hide_witnesses);
813 }
814 }
815 klassOop find_witness_definer(klassOop context_type, DepChange* changes = NULL) {
816 assert(!doing_subtype_search(), "must set up a method definer search");
817 // When looking for unexpected concrete methods,
818 // look beneath expected ones, to see if there are overrides.
819 const bool participants_hide_witnesses = true;
820 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
821 if (changes != NULL) {
822 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
823 } else {
824 return find_witness_anywhere(context_type, !participants_hide_witnesses);
825 }
826 }
827 };
828
829 #ifndef PRODUCT
830 static int deps_find_witness_calls = 0;
831 static int deps_find_witness_steps = 0;
832 static int deps_find_witness_recursions = 0;
833 static int deps_find_witness_singles = 0;
834 static int deps_find_witness_print = 0; // set to -1 to force a final print
835 static bool count_find_witness_calls() {
836 if (TraceDependencies || LogCompilation) {
837 int pcount = deps_find_witness_print + 1;
838 bool final_stats = (pcount == 0);
839 bool initial_call = (pcount == 1);
840 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
841 if (pcount < 0) pcount = 1; // crude overflow protection
842 deps_find_witness_print = pcount;
843 if (VerifyDependencies && initial_call) {
844 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
845 }
846 if (occasional_print || final_stats) {
847 // Every now and then dump a little info about dependency searching.
848 if (xtty != NULL) {
849 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
850 deps_find_witness_calls,
851 deps_find_witness_steps,
852 deps_find_witness_recursions,
853 deps_find_witness_singles);
854 }
855 if (final_stats || (TraceDependencies && WizardMode)) {
856 tty->print_cr("Dependency check (find_witness) "
857 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
858 deps_find_witness_calls,
859 deps_find_witness_steps,
860 (double)deps_find_witness_steps / deps_find_witness_calls,
861 deps_find_witness_recursions,
862 deps_find_witness_singles);
863 }
864 }
865 return true;
866 }
867 return false;
868 }
869 #else
870 #define count_find_witness_calls() (0)
871 #endif //PRODUCT
872
873
874 klassOop ClassHierarchyWalker::find_witness_in(DepChange& changes,
875 klassOop context_type,
876 bool participants_hide_witnesses) {
877 assert(changes.involves_context(context_type), "irrelevant dependency");
878 klassOop new_type = changes.new_type();
879
880 count_find_witness_calls();
881 NOT_PRODUCT(deps_find_witness_singles++);
882
883 // Current thread must be in VM (not native mode, as in CI):
884 assert(must_be_in_vm(), "raw oops here");
885 // Must not move the class hierarchy during this check:
886 assert_locked_or_safepoint(Compile_lock);
887
888 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
889 if (nof_impls > 1) {
890 // Avoid this case: *I.m > { A.m, C }; B.m > C
891 // %%% Until this is fixed more systematically, bail out.
892 // See corresponding comment in find_witness_anywhere.
893 return context_type;
894 }
895
896 assert(!is_participant(new_type), "only old classes are participants");
897 if (participants_hide_witnesses) {
898 // If the new type is a subtype of a participant, we are done.
899 for (int i = 0; i < num_participants(); i++) {
900 klassOop part = participant(i);
901 if (part == NULL) continue;
902 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part),
903 "correct marking of participants, b/c new_type is unique");
904 if (changes.involves_context(part)) {
905 // new guy is protected from this check by previous participant
906 return NULL;
907 }
908 }
909 }
910
911 if (is_witness(new_type) &&
912 !ignore_witness(new_type)) {
913 return new_type;
914 }
915
916 return NULL;
917 }
918
919
920 // Walk hierarchy under a context type, looking for unexpected types.
921 // Do not report participant types, and recursively walk beneath
922 // them only if participants_hide_witnesses is false.
923 // If top_level_call is false, skip testing the context type,
924 // because the caller has already considered it.
925 klassOop ClassHierarchyWalker::find_witness_anywhere(klassOop context_type,
926 bool participants_hide_witnesses,
927 bool top_level_call) {
928 // Current thread must be in VM (not native mode, as in CI):
929 assert(must_be_in_vm(), "raw oops here");
930 // Must not move the class hierarchy during this check:
931 assert_locked_or_safepoint(Compile_lock);
932
933 bool do_counts = count_find_witness_calls();
934
935 // Check the root of the sub-hierarchy first.
936 if (top_level_call) {
937 if (do_counts) {
938 NOT_PRODUCT(deps_find_witness_calls++);
939 NOT_PRODUCT(deps_find_witness_steps++);
940 }
941 if (is_participant(context_type)) {
942 if (participants_hide_witnesses) return NULL;
943 // else fall through to search loop...
944 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
945 // The context is an abstract class or interface, to start with.
946 return context_type;
947 }
948 }
949
950 // Now we must check each implementor and each subclass.
951 // Use a short worklist to avoid blowing the stack.
952 // Each worklist entry is a *chain* of subklass siblings to process.
953 const int CHAINMAX = 100; // >= 1 + instanceKlass::implementors_limit
954 Klass* chains[CHAINMAX];
955 int chaini = 0; // index into worklist
956 Klass* chain; // scratch variable
957 #define ADD_SUBCLASS_CHAIN(k) { \
958 assert(chaini < CHAINMAX, "oob"); \
959 chain = instanceKlass::cast(k)->subklass(); \
960 if (chain != NULL) chains[chaini++] = chain; }
961
962 // Look for non-abstract subclasses.
963 // (Note: Interfaces do not have subclasses.)
964 ADD_SUBCLASS_CHAIN(context_type);
965
966 // If it is an interface, search its direct implementors.
967 // (Their subclasses are additional indirect implementors.
968 // See instanceKlass::add_implementor.)
969 // (Note: nof_implementors is always zero for non-interfaces.)
970 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
971 if (nof_impls > 1) {
972 // Avoid this case: *I.m > { A.m, C }; B.m > C
973 // Here, I.m has 2 concrete implementations, but m appears unique
974 // as A.m, because the search misses B.m when checking C.
975 // The inherited method B.m was getting missed by the walker
976 // when interface 'I' was the starting point.
977 // %%% Until this is fixed more systematically, bail out.
978 // (Old CHA had the same limitation.)
979 return context_type;
980 }
981 for (int i = 0; i < nof_impls; i++) {
982 klassOop impl = instanceKlass::cast(context_type)->implementor(i);
983 if (impl == NULL) {
984 // implementors array overflowed => no exact info.
985 return context_type; // report an inexact witness to this sad affair
986 }
987 if (do_counts)
988 { NOT_PRODUCT(deps_find_witness_steps++); }
989 if (is_participant(impl)) {
990 if (participants_hide_witnesses) continue;
991 // else fall through to process this guy's subclasses
992 } else if (is_witness(impl) && !ignore_witness(impl)) {
993 return impl;
994 }
995 ADD_SUBCLASS_CHAIN(impl);
996 }
997
998 // Recursively process each non-trivial sibling chain.
999 while (chaini > 0) {
1000 Klass* chain = chains[--chaini];
1001 for (Klass* subk = chain; subk != NULL; subk = subk->next_sibling()) {
1002 klassOop sub = subk->as_klassOop();
1003 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1004 if (is_participant(sub)) {
1005 if (participants_hide_witnesses) continue;
1006 // else fall through to process this guy's subclasses
1007 } else if (is_witness(sub) && !ignore_witness(sub)) {
1008 return sub;
1009 }
1010 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1011 // Fast path. (Partially disabled if VerifyDependencies.)
1012 ADD_SUBCLASS_CHAIN(sub);
1013 } else {
1014 // Worklist overflow. Do a recursive call. Should be rare.
1015 // The recursive call will have its own worklist, of course.
1016 // (Note that sub has already been tested, so that there is
1017 // no need for the recursive call to re-test. That's handy,
1018 // since the recursive call sees sub as the context_type.)
1019 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1020 klassOop witness = find_witness_anywhere(sub,
1021 participants_hide_witnesses,
1022 /*top_level_call=*/ false);
1023 if (witness != NULL) return witness;
1024 }
1025 }
1026 }
1027
1028 // No witness found. The dependency remains unbroken.
1029 return NULL;
1030 #undef ADD_SUBCLASS_CHAIN
1031 }
1032
1033
1034 bool Dependencies::is_concrete_klass(klassOop k) {
1035 if (Klass::cast(k)->is_abstract()) return false;
1036 // %%% We could treat classes which are concrete but
1037 // have not yet been instantiated as virtually abstract.
1038 // This would require a deoptimization barrier on first instantiation.
1039 //if (k->is_not_instantiated()) return false;
1040 return true;
1041 }
1042
1043 bool Dependencies::is_concrete_method(methodOop m) {
1044 if (m->is_abstract()) return false;
1045 // %%% We could treat unexecuted methods as virtually abstract also.
1046 // This would require a deoptimization barrier on first execution.
1047 return !m->is_abstract();
1048 }
1049
1050
1051 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1052 if (k->is_interface()) return NULL;
1053 if (k->has_finalizer()) return k;
1054 k = k->subklass();
1055 while (k != NULL) {
1056 Klass* result = find_finalizable_subclass(k);
1057 if (result != NULL) return result;
1058 k = k->next_sibling();
1059 }
1060 return NULL;
1061 }
1062
1063
1064 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1065 if (k->is_abstract()) return false;
1066 // We could return also false if k does not yet appear to be
1067 // instantiated, if the VM version supports this distinction also.
1068 //if (k->is_not_instantiated()) return false;
1069 return true;
1070 }
1071
1072 bool Dependencies::is_concrete_method(ciMethod* m) {
1073 // Statics are irrelevant to virtual call sites.
1074 if (m->is_static()) return false;
1075
1076 // We could return also false if m does not yet appear to be
1077 // executed, if the VM version supports this distinction also.
1078 return !m->is_abstract();
1079 }
1080
1081
1082 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1083 return k->has_finalizable_subclass();
1084 }
1085
1086
1087 // Any use of the contents (bytecodes) of a method must be
1088 // marked by an "evol_method" dependency, if those contents
1089 // can change. (Note: A method is always dependent on itself.)
1090 klassOop Dependencies::check_evol_method(methodOop m) {
1091 assert(must_be_in_vm(), "raw oops here");
1092 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1093 // Or is there a now a breakpoint?
1094 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1095 if (m->is_old()
1096 || m->number_of_breakpoints() > 0) {
1097 return m->method_holder();
1098 } else {
1099 return NULL;
1100 }
1101 }
1102
1103 // This is a strong assertion: It is that the given type
1104 // has no subtypes whatever. It is most useful for
1105 // optimizing checks on reflected types or on array types.
1106 // (Checks on types which are derived from real instances
1107 // can be optimized more strongly than this, because we
1108 // know that the checked type comes from a concrete type,
1109 // and therefore we can disregard abstract types.)
1110 klassOop Dependencies::check_leaf_type(klassOop ctxk) {
1111 assert(must_be_in_vm(), "raw oops here");
1112 assert_locked_or_safepoint(Compile_lock);
1113 instanceKlass* ctx = instanceKlass::cast(ctxk);
1114 Klass* sub = ctx->subklass();
1115 if (sub != NULL) {
1116 return sub->as_klassOop();
1117 } else if (ctx->nof_implementors() != 0) {
1118 // if it is an interface, it must be unimplemented
1119 // (if it is not an interface, nof_implementors is always zero)
1120 klassOop impl = ctx->implementor(0);
1121 return (impl != NULL)? impl: ctxk;
1122 } else {
1123 return NULL;
1124 }
1125 }
1126
1127 // Test the assertion that conck is the only concrete subtype* of ctxk.
1128 // The type conck itself is allowed to have have further concrete subtypes.
1129 // This allows the compiler to narrow occurrences of ctxk by conck,
1130 // when dealing with the types of actual instances.
1131 klassOop Dependencies::check_abstract_with_unique_concrete_subtype(klassOop ctxk,
1132 klassOop conck,
1133 DepChange* changes) {
1134 ClassHierarchyWalker wf(conck);
1135 return wf.find_witness_subtype(ctxk, changes);
1136 }
1137
1138 // If a non-concrete class has no concrete subtypes, it is not (yet)
1139 // instantiatable. This can allow the compiler to make some paths go
1140 // dead, if they are gated by a test of the type.
1141 klassOop Dependencies::check_abstract_with_no_concrete_subtype(klassOop ctxk,
1142 DepChange* changes) {
1143 // Find any concrete subtype, with no participants:
1144 ClassHierarchyWalker wf;
1145 return wf.find_witness_subtype(ctxk, changes);
1146 }
1147
1148
1149 // If a concrete class has no concrete subtypes, it can always be
1150 // exactly typed. This allows the use of a cheaper type test.
1151 klassOop Dependencies::check_concrete_with_no_concrete_subtype(klassOop ctxk,
1152 DepChange* changes) {
1153 // Find any concrete subtype, with only the ctxk as participant:
1154 ClassHierarchyWalker wf(ctxk);
1155 return wf.find_witness_subtype(ctxk, changes);
1156 }
1157
1158
1159 // Find the unique concrete proper subtype of ctxk, or NULL if there
1160 // is more than one concrete proper subtype. If there are no concrete
1161 // proper subtypes, return ctxk itself, whether it is concrete or not.
1162 // The returned subtype is allowed to have have further concrete subtypes.
1163 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1164 klassOop Dependencies::find_unique_concrete_subtype(klassOop ctxk) {
1165 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1166 wf.record_witnesses(1); // Record one other witness when walking.
1167 klassOop wit = wf.find_witness_subtype(ctxk);
1168 if (wit != NULL) return NULL; // Too many witnesses.
1169 klassOop conck = wf.participant(0);
1170 if (conck == NULL) {
1171 #ifndef PRODUCT
1172 // Make sure the dependency mechanism will pass this discovery:
1173 if (VerifyDependencies) {
1174 // Turn off dependency tracing while actually testing deps.
1175 FlagSetting fs(TraceDependencies, false);
1176 if (!Dependencies::is_concrete_klass(ctxk)) {
1177 guarantee(NULL ==
1178 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1179 "verify dep.");
1180 } else {
1181 guarantee(NULL ==
1182 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1183 "verify dep.");
1184 }
1185 }
1186 #endif //PRODUCT
1187 return ctxk; // Return ctxk as a flag for "no subtypes".
1188 } else {
1189 #ifndef PRODUCT
1190 // Make sure the dependency mechanism will pass this discovery:
1191 if (VerifyDependencies) {
1192 // Turn off dependency tracing while actually testing deps.
1193 FlagSetting fs(TraceDependencies, false);
1194 if (!Dependencies::is_concrete_klass(ctxk)) {
1195 guarantee(NULL == (void *)
1196 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1197 "verify dep.");
1198 }
1199 }
1200 #endif //PRODUCT
1201 return conck;
1202 }
1203 }
1204
1205 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1206 // except possibly for further subtypes of k[12] themselves.
1207 // The context type must be abstract. The types k1 and k2 are themselves
1208 // allowed to have further concrete subtypes.
1209 klassOop Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1210 klassOop ctxk,
1211 klassOop k1,
1212 klassOop k2,
1213 DepChange* changes) {
1214 ClassHierarchyWalker wf;
1215 wf.add_participant(k1);
1216 wf.add_participant(k2);
1217 return wf.find_witness_subtype(ctxk, changes);
1218 }
1219
1220 // Search ctxk for concrete implementations. If there are klen or fewer,
1221 // pack them into the given array and return the number.
1222 // Otherwise, return -1, meaning the given array would overflow.
1223 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1224 // In this search, if ctxk is concrete, it will be reported alone.
1225 // For any type CC reported, no proper subtypes of CC will be reported.
1226 int Dependencies::find_exclusive_concrete_subtypes(klassOop ctxk,
1227 int klen,
1228 klassOop karray[]) {
1229 ClassHierarchyWalker wf;
1230 wf.record_witnesses(klen);
1231 klassOop wit = wf.find_witness_subtype(ctxk);
1232 if (wit != NULL) return -1; // Too many witnesses.
1233 int num = wf.num_participants();
1234 assert(num <= klen, "oob");
1235 // Pack the result array with the good news.
1236 for (int i = 0; i < num; i++)
1237 karray[i] = wf.participant(i);
1238 #ifndef PRODUCT
1239 // Make sure the dependency mechanism will pass this discovery:
1240 if (VerifyDependencies) {
1241 // Turn off dependency tracing while actually testing deps.
1242 FlagSetting fs(TraceDependencies, false);
1243 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1244 case -1: // ctxk was itself concrete
1245 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1246 break;
1247 case 0:
1248 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1249 "verify dep.");
1250 break;
1251 case 1:
1252 guarantee(NULL == (void *)
1253 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1254 "verify dep.");
1255 break;
1256 case 2:
1257 guarantee(NULL == (void *)
1258 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1259 karray[0],
1260 karray[1]),
1261 "verify dep.");
1262 break;
1263 default:
1264 ShouldNotReachHere(); // klen > 2 yet supported
1265 }
1266 }
1267 #endif //PRODUCT
1268 return num;
1269 }
1270
1271 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1272 // Otherwise, return a class that contains an interfering method.
1273 klassOop Dependencies::check_unique_concrete_method(klassOop ctxk, methodOop uniqm,
1274 DepChange* changes) {
1275 // Here is a missing optimization: If uniqm->is_final(),
1276 // we don't really need to search beneath it for overrides.
1277 // This is probably not important, since we don't use dependencies
1278 // to track final methods. (They can't be "definalized".)
1279 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1280 return wf.find_witness_definer(ctxk, changes);
1281 }
1282
1283 // Find the set of all non-abstract methods under ctxk that match m.
1284 // (The method m must be defined or inherited in ctxk.)
1285 // Include m itself in the set, unless it is abstract.
1286 // If this set has exactly one element, return that element.
1287 methodOop Dependencies::find_unique_concrete_method(klassOop ctxk, methodOop m) {
1288 ClassHierarchyWalker wf(m);
1289 assert(wf.check_method_context(ctxk, m), "proper context");
1290 wf.record_witnesses(1);
1291 klassOop wit = wf.find_witness_definer(ctxk);
1292 if (wit != NULL) return NULL; // Too many witnesses.
1293 methodOop fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1294 if (Dependencies::is_concrete_method(m)) {
1295 if (fm == NULL) {
1296 // It turns out that m was always the only implementation.
1297 fm = m;
1298 } else if (fm != m) {
1299 // Two conflicting implementations after all.
1300 // (This can happen if m is inherited into ctxk and fm overrides it.)
1301 return NULL;
1302 }
1303 }
1304 #ifndef PRODUCT
1305 // Make sure the dependency mechanism will pass this discovery:
1306 if (VerifyDependencies && fm != NULL) {
1307 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1308 "verify dep.");
1309 }
1310 #endif //PRODUCT
1311 return fm;
1312 }
1313
1314 klassOop Dependencies::check_exclusive_concrete_methods(klassOop ctxk,
1315 methodOop m1,
1316 methodOop m2,
1317 DepChange* changes) {
1318 ClassHierarchyWalker wf(m1);
1319 wf.add_participant(m1->method_holder());
1320 wf.add_participant(m2->method_holder());
1321 return wf.find_witness_definer(ctxk, changes);
1322 }
1323
1324 // Find the set of all non-abstract methods under ctxk that match m[0].
1325 // (The method m[0] must be defined or inherited in ctxk.)
1326 // Include m itself in the set, unless it is abstract.
1327 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1328 // (The length may be zero if no concrete methods are found anywhere.)
1329 // If there are too many concrete methods to fit in marray, return -1.
1330 int Dependencies::find_exclusive_concrete_methods(klassOop ctxk,
1331 int mlen,
1332 methodOop marray[]) {
1333 methodOop m0 = marray[0];
1334 ClassHierarchyWalker wf(m0);
1335 assert(wf.check_method_context(ctxk, m0), "proper context");
1336 wf.record_witnesses(mlen);
1337 bool participants_hide_witnesses = true;
1338 klassOop wit = wf.find_witness_definer(ctxk);
1339 if (wit != NULL) return -1; // Too many witnesses.
1340 int num = wf.num_participants();
1341 assert(num <= mlen, "oob");
1342 // Keep track of whether m is also part of the result set.
1343 int mfill = 0;
1344 assert(marray[mfill] == m0, "sanity");
1345 if (Dependencies::is_concrete_method(m0))
1346 mfill++; // keep m0 as marray[0], the first result
1347 for (int i = 0; i < num; i++) {
1348 methodOop fm = wf.found_method(i);
1349 if (fm == m0) continue; // Already put this guy in the list.
1350 if (mfill == mlen) {
1351 return -1; // Oops. Too many methods after all!
1352 }
1353 marray[mfill++] = fm;
1354 }
1355 #ifndef PRODUCT
1356 // Make sure the dependency mechanism will pass this discovery:
1357 if (VerifyDependencies) {
1358 // Turn off dependency tracing while actually testing deps.
1359 FlagSetting fs(TraceDependencies, false);
1360 switch (mfill) {
1361 case 1:
1362 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1363 "verify dep.");
1364 break;
1365 case 2:
1366 guarantee(NULL == (void *)
1367 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1368 "verify dep.");
1369 break;
1370 default:
1371 ShouldNotReachHere(); // mlen > 2 yet supported
1372 }
1373 }
1374 #endif //PRODUCT
1375 return mfill;
1376 }
1377
1378
1379 klassOop Dependencies::check_has_no_finalizable_subclasses(klassOop ctxk, DepChange* changes) {
1380 Klass* search_at = ctxk->klass_part();
1381 if (changes != NULL)
1382 search_at = changes->new_type()->klass_part(); // just look at the new bit
1383 Klass* result = find_finalizable_subclass(search_at);
1384 if (result == NULL) {
1385 return NULL;
1386 }
1387 return result->as_klassOop();
1388 }
1389
1390
1391 klassOop Dependencies::DepStream::check_dependency_impl(DepChange* changes) {
1392 assert_locked_or_safepoint(Compile_lock);
1393
1394 klassOop witness = NULL;
1395 switch (type()) {
1396 case evol_method:
1397 witness = check_evol_method(method_argument(0));
1398 break;
1399 case leaf_type:
1400 witness = check_leaf_type(context_type());
1401 break;
1402 case abstract_with_unique_concrete_subtype:
1403 witness = check_abstract_with_unique_concrete_subtype(context_type(),
1404 type_argument(1),
1405 changes);
1406 break;
1407 case abstract_with_no_concrete_subtype:
1408 witness = check_abstract_with_no_concrete_subtype(context_type(),
1409 changes);
1410 break;
1411 case concrete_with_no_concrete_subtype:
1412 witness = check_concrete_with_no_concrete_subtype(context_type(),
1413 changes);
1414 break;
1415 case unique_concrete_method:
1416 witness = check_unique_concrete_method(context_type(),
1417 method_argument(1),
1418 changes);
1419 break;
1420 case abstract_with_exclusive_concrete_subtypes_2:
1421 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(),
1422 type_argument(1),
1423 type_argument(2),
1424 changes);
1425 break;
1426 case exclusive_concrete_methods_2:
1427 witness = check_exclusive_concrete_methods(context_type(),
1428 method_argument(1),
1429 method_argument(2),
1430 changes);
1431 break;
1432 case no_finalizable_subclasses:
1433 witness = check_has_no_finalizable_subclasses(context_type(),
1434 changes);
1435 break;
1436 default:
1437 witness = NULL;
1438 ShouldNotReachHere();
1439 break;
1440 }
1441 if (witness != NULL) {
1442 if (TraceDependencies) {
1443 print_dependency(witness, /*verbose=*/ true);
1444 }
1445 // The following is a no-op unless logging is enabled:
1446 log_dependency(witness);
1447 }
1448 return witness;
1449 }
1450
1451
1452 klassOop Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1453 if (!changes.involves_context(context_type()))
1454 // irrelevant dependency; skip it
1455 return NULL;
1456
1457 return check_dependency_impl(&changes);
1458 }
1459
1460
1461 void DepChange::initialize() {
1462 // entire transaction must be under this lock:
1463 assert_lock_strong(Compile_lock);
1464
1465 // Mark all dependee and all its superclasses
1466 // Mark transitive interfaces
1467 for (ContextStream str(*this); str.next(); ) {
1468 klassOop d = str.klass();
1469 assert(!instanceKlass::cast(d)->is_marked_dependent(), "checking");
1470 instanceKlass::cast(d)->set_is_marked_dependent(true);
1471 }
1472 }
1473
1474 DepChange::~DepChange() {
1475 // Unmark all dependee and all its superclasses
1476 // Unmark transitive interfaces
1477 for (ContextStream str(*this); str.next(); ) {
1478 klassOop d = str.klass();
1479 instanceKlass::cast(d)->set_is_marked_dependent(false);
1480 }
1481 }
1482
1483 bool DepChange::involves_context(klassOop k) {
1484 if (k == NULL || !Klass::cast(k)->oop_is_instance()) {
1485 return false;
1486 }
1487 instanceKlass* ik = instanceKlass::cast(k);
1488 bool is_contained = ik->is_marked_dependent();
1489 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k),
1490 "correct marking of potential context types");
1491 return is_contained;
1492 }
1493
1494 bool DepChange::ContextStream::next() {
1495 switch (_change_type) {
1496 case Start_Klass: // initial state; _klass is the new type
1497 _ti_base = instanceKlass::cast(_klass)->transitive_interfaces();
1498 _ti_index = 0;
1499 _change_type = Change_new_type;
1500 return true;
1501 case Change_new_type:
1502 // fall through:
1503 _change_type = Change_new_sub;
1504 case Change_new_sub:
1505 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1506 {
1507 _klass = instanceKlass::cast(_klass)->super();
1508 if (_klass != NULL) {
1509 return true;
1510 }
1511 }
1512 // else set up _ti_limit and fall through:
1513 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1514 _change_type = Change_new_impl;
1515 case Change_new_impl:
1516 if (_ti_index < _ti_limit) {
1517 _klass = klassOop( _ti_base->obj_at(_ti_index++) );
1518 return true;
1519 }
1520 // fall through:
1521 _change_type = NO_CHANGE; // iterator is exhausted
1522 case NO_CHANGE:
1523 break;
1524 default:
1525 ShouldNotReachHere();
1526 }
1527 return false;
1528 }
1529
1530 void DepChange::print() {
1531 int nsup = 0, nint = 0;
1532 for (ContextStream str(*this); str.next(); ) {
1533 klassOop k = str.klass();
1534 switch (str._change_type) {
1535 case Change_new_type:
1536 tty->print_cr(" dependee = %s", instanceKlass::cast(k)->external_name());
1537 break;
1538 case Change_new_sub:
1539 if (!WizardMode)
1540 ++nsup;
1541 else tty->print_cr(" context super = %s", instanceKlass::cast(k)->external_name());
1542 break;
1543 case Change_new_impl:
1544 if (!WizardMode)
1545 ++nint;
1546 else tty->print_cr(" context interface = %s", instanceKlass::cast(k)->external_name());
1547 break;
1548 }
1549 }
1550 if (nsup + nint != 0) {
1551 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1552 }
1553 }
1554
1555 #ifndef PRODUCT
1556 void Dependencies::print_statistics() {
1557 if (deps_find_witness_print != 0) {
1558 // Call one final time, to flush out the data.
1559 deps_find_witness_print = -1;
1560 count_find_witness_calls();
1561 }
1562 }
1563 #endif