1 /*
2 * Copyright (c) 2005, 2013, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciArrayKlass.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "ci/ciKlass.hpp"
29 #include "ci/ciMethod.hpp"
30 #include "code/dependencies.hpp"
31 #include "compiler/compileLog.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/handles.hpp"
34 #include "runtime/handles.inline.hpp"
35 #include "runtime/thread.inline.hpp"
36 #include "utilities/copy.hpp"
37
38
39 #ifdef ASSERT
40 static bool must_be_in_vm() {
41 Thread* thread = Thread::current();
42 if (thread->is_Java_thread())
43 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
44 else
45 return true; //something like this: thread->is_VM_thread();
46 }
47 #endif //ASSERT
48
49 void Dependencies::initialize(ciEnv* env) {
50 Arena* arena = env->arena();
51 _oop_recorder = env->oop_recorder();
52 _log = env->log();
53 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
54 DEBUG_ONLY(_deps[end_marker] = NULL);
55 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
56 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
57 }
58 _content_bytes = NULL;
59 _size_in_bytes = (size_t)-1;
60
61 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
62 }
63
64 void Dependencies::assert_evol_method(ciMethod* m) {
65 assert_common_1(evol_method, m);
66 }
67
68 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
69 if (ctxk->is_array_klass()) {
70 // As a special case, support this assertion on an array type,
71 // which reduces to an assertion on its element type.
72 // Note that this cannot be done with assertions that
73 // relate to concreteness or abstractness.
74 ciType* elemt = ctxk->as_array_klass()->base_element_type();
75 if (!elemt->is_instance_klass()) return; // Ex: int[][]
76 ctxk = elemt->as_instance_klass();
77 //if (ctxk->is_final()) return; // Ex: String[][]
78 }
79 check_ctxk(ctxk);
80 assert_common_1(leaf_type, ctxk);
81 }
82
83 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
84 check_ctxk_abstract(ctxk);
85 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
86 }
87
88 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
89 check_ctxk_abstract(ctxk);
90 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
91 }
92
93 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
94 check_ctxk_concrete(ctxk);
95 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
96 }
97
98 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
99 check_ctxk(ctxk);
100 assert_common_2(unique_concrete_method, ctxk, uniqm);
101 }
102
103 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
104 check_ctxk(ctxk);
105 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
106 }
107
108 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
109 check_ctxk(ctxk);
110 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
111 }
112
113 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
114 check_ctxk(ctxk);
115 assert_common_1(no_finalizable_subclasses, ctxk);
116 }
117
118 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
119 check_ctxk(call_site->klass());
120 assert_common_2(call_site_target_value, call_site, method_handle);
121 }
122
123 // Helper function. If we are adding a new dep. under ctxk2,
124 // try to find an old dep. under a broader* ctxk1. If there is
125 //
126 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
127 int ctxk_i, ciKlass* ctxk2) {
128 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
129 if (ctxk2->is_subtype_of(ctxk1)) {
130 return true; // success, and no need to change
131 } else if (ctxk1->is_subtype_of(ctxk2)) {
132 // new context class fully subsumes previous one
133 deps->at_put(ctxk_i, ctxk2);
134 return true;
135 } else {
136 return false;
137 }
138 }
139
140 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
141 assert(dep_args(dept) == 1, "sanity");
142 log_dependency(dept, x);
143 GrowableArray<ciBaseObject*>* deps = _deps[dept];
144
145 // see if the same (or a similar) dep is already recorded
146 if (note_dep_seen(dept, x)) {
147 assert(deps->find(x) >= 0, "sanity");
148 } else {
149 deps->append(x);
150 }
151 }
152
153 void Dependencies::assert_common_2(DepType dept,
154 ciBaseObject* x0, ciBaseObject* x1) {
155 assert(dep_args(dept) == 2, "sanity");
156 log_dependency(dept, x0, x1);
157 GrowableArray<ciBaseObject*>* deps = _deps[dept];
158
159 // see if the same (or a similar) dep is already recorded
160 bool has_ctxk = has_explicit_context_arg(dept);
161 if (has_ctxk) {
162 assert(dep_context_arg(dept) == 0, "sanity");
163 if (note_dep_seen(dept, x1)) {
164 // look in this bucket for redundant assertions
165 const int stride = 2;
166 for (int i = deps->length(); (i -= stride) >= 0; ) {
167 ciBaseObject* y1 = deps->at(i+1);
168 if (x1 == y1) { // same subject; check the context
169 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
170 return;
171 }
172 }
173 }
174 }
175 } else {
176 assert(dep_implicit_context_arg(dept) == 0, "sanity");
177 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
178 // look in this bucket for redundant assertions
179 const int stride = 2;
180 for (int i = deps->length(); (i -= stride) >= 0; ) {
181 ciBaseObject* y0 = deps->at(i+0);
182 ciBaseObject* y1 = deps->at(i+1);
183 if (x0 == y0 && x1 == y1) {
184 return;
185 }
186 }
187 }
188 }
189
190 // append the assertion in the correct bucket:
191 deps->append(x0);
192 deps->append(x1);
193 }
194
195 void Dependencies::assert_common_3(DepType dept,
196 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
197 assert(dep_context_arg(dept) == 0, "sanity");
198 assert(dep_args(dept) == 3, "sanity");
199 log_dependency(dept, ctxk, x, x2);
200 GrowableArray<ciBaseObject*>* deps = _deps[dept];
201
202 // try to normalize an unordered pair:
203 bool swap = false;
204 switch (dept) {
205 case abstract_with_exclusive_concrete_subtypes_2:
206 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
207 break;
208 case exclusive_concrete_methods_2:
209 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
210 break;
211 }
212 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
213
214 // see if the same (or a similar) dep is already recorded
215 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
216 // look in this bucket for redundant assertions
217 const int stride = 3;
218 for (int i = deps->length(); (i -= stride) >= 0; ) {
219 ciBaseObject* y = deps->at(i+1);
220 ciBaseObject* y2 = deps->at(i+2);
221 if (x == y && x2 == y2) { // same subjects; check the context
222 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
223 return;
224 }
225 }
226 }
227 }
228 // append the assertion in the correct bucket:
229 deps->append(ctxk);
230 deps->append(x);
231 deps->append(x2);
232 }
233
234 /// Support for encoding dependencies into an nmethod:
235
236 void Dependencies::copy_to(nmethod* nm) {
237 address beg = nm->dependencies_begin();
238 address end = nm->dependencies_end();
239 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
240 Copy::disjoint_words((HeapWord*) content_bytes(),
241 (HeapWord*) beg,
242 size_in_bytes() / sizeof(HeapWord));
243 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
244 }
245
246 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
247 for (int i = 0; i < narg; i++) {
248 int diff = p1[i]->ident() - p2[i]->ident();
249 if (diff != 0) return diff;
250 }
251 return 0;
252 }
253 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
254 { return sort_dep(p1, p2, 1); }
255 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
256 { return sort_dep(p1, p2, 2); }
257 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
258 { return sort_dep(p1, p2, 3); }
259
260 void Dependencies::sort_all_deps() {
261 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
262 DepType dept = (DepType)deptv;
263 GrowableArray<ciBaseObject*>* deps = _deps[dept];
264 if (deps->length() <= 1) continue;
265 switch (dep_args(dept)) {
266 case 1: deps->sort(sort_dep_arg_1, 1); break;
267 case 2: deps->sort(sort_dep_arg_2, 2); break;
268 case 3: deps->sort(sort_dep_arg_3, 3); break;
269 default: ShouldNotReachHere();
270 }
271 }
272 }
273
274 size_t Dependencies::estimate_size_in_bytes() {
275 size_t est_size = 100;
276 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
277 DepType dept = (DepType)deptv;
278 GrowableArray<ciBaseObject*>* deps = _deps[dept];
279 est_size += deps->length()*2; // tags and argument(s)
280 }
281 return est_size;
282 }
283
284 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
285 switch (dept) {
286 case abstract_with_exclusive_concrete_subtypes_2:
287 return x->as_metadata()->as_klass();
288 case unique_concrete_method:
289 case exclusive_concrete_methods_2:
290 return x->as_metadata()->as_method()->holder();
291 }
292 return NULL; // let NULL be NULL
293 }
294
295 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
296 assert(must_be_in_vm(), "raw oops here");
297 switch (dept) {
298 case abstract_with_exclusive_concrete_subtypes_2:
299 assert(x->is_klass(), "sanity");
300 return (Klass*) x;
301 case unique_concrete_method:
302 case exclusive_concrete_methods_2:
303 assert(x->is_method(), "sanity");
304 return ((Method*)x)->method_holder();
305 }
306 return NULL; // let NULL be NULL
307 }
308
309 void Dependencies::encode_content_bytes() {
310 sort_all_deps();
311
312 // cast is safe, no deps can overflow INT_MAX
313 CompressedWriteStream bytes((int)estimate_size_in_bytes());
314
315 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
316 DepType dept = (DepType)deptv;
317 GrowableArray<ciBaseObject*>* deps = _deps[dept];
318 if (deps->length() == 0) continue;
319 int stride = dep_args(dept);
320 int ctxkj = dep_context_arg(dept); // -1 if no context arg
321 assert(stride > 0, "sanity");
322 for (int i = 0; i < deps->length(); i += stride) {
323 jbyte code_byte = (jbyte)dept;
324 int skipj = -1;
325 if (ctxkj >= 0 && ctxkj+1 < stride) {
326 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
327 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
328 if (ctxk == ctxk_encoded_as_null(dept, x)) {
329 skipj = ctxkj; // we win: maybe one less oop to keep track of
330 code_byte |= default_context_type_bit;
331 }
332 }
333 bytes.write_byte(code_byte);
334 for (int j = 0; j < stride; j++) {
335 if (j == skipj) continue;
336 ciBaseObject* v = deps->at(i+j);
337 int idx;
338 if (v->is_object()) {
339 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
340 } else {
341 ciMetadata* meta = v->as_metadata();
342 idx = _oop_recorder->find_index(meta->constant_encoding());
343 }
344 bytes.write_int(idx);
345 }
346 }
347 }
348
349 // write a sentinel byte to mark the end
350 bytes.write_byte(end_marker);
351
352 // round it out to a word boundary
353 while (bytes.position() % sizeof(HeapWord) != 0) {
354 bytes.write_byte(end_marker);
355 }
356
357 // check whether the dept byte encoding really works
358 assert((jbyte)default_context_type_bit != 0, "byte overflow");
359
360 _content_bytes = bytes.buffer();
361 _size_in_bytes = bytes.position();
362 }
363
364
365 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
366 "end_marker",
367 "evol_method",
368 "leaf_type",
369 "abstract_with_unique_concrete_subtype",
370 "abstract_with_no_concrete_subtype",
371 "concrete_with_no_concrete_subtype",
372 "unique_concrete_method",
373 "abstract_with_exclusive_concrete_subtypes_2",
374 "exclusive_concrete_methods_2",
375 "no_finalizable_subclasses",
376 "call_site_target_value"
377 };
378
379 int Dependencies::_dep_args[TYPE_LIMIT] = {
380 -1,// end_marker
381 1, // evol_method m
382 1, // leaf_type ctxk
383 2, // abstract_with_unique_concrete_subtype ctxk, k
384 1, // abstract_with_no_concrete_subtype ctxk
385 1, // concrete_with_no_concrete_subtype ctxk
386 2, // unique_concrete_method ctxk, m
387 3, // unique_concrete_subtypes_2 ctxk, k1, k2
388 3, // unique_concrete_methods_2 ctxk, m1, m2
389 1, // no_finalizable_subclasses ctxk
390 2 // call_site_target_value call_site, method_handle
391 };
392
393 const char* Dependencies::dep_name(Dependencies::DepType dept) {
394 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
395 return _dep_name[dept];
396 }
397
398 int Dependencies::dep_args(Dependencies::DepType dept) {
399 if (!dept_in_mask(dept, all_types)) return -1;
400 return _dep_args[dept];
401 }
402
403 void Dependencies::check_valid_dependency_type(DepType dept) {
404 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
405 }
406
407 // for the sake of the compiler log, print out current dependencies:
408 void Dependencies::log_all_dependencies() {
409 if (log() == NULL) return;
410 ResourceMark rm;
411 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
412 DepType dept = (DepType)deptv;
413 GrowableArray<ciBaseObject*>* deps = _deps[dept];
414 int deplen = deps->length();
415 if (deplen == 0) {
416 continue;
417 }
418 int stride = dep_args(dept);
419 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
420 for (int i = 0; i < deps->length(); i += stride) {
421 for (int j = 0; j < stride; j++) {
422 // flush out the identities before printing
423 ciargs->push(deps->at(i+j));
424 }
425 write_dependency_to(log(), dept, ciargs);
426 ciargs->clear();
427 }
428 guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
429 }
430 }
431
432 void Dependencies::write_dependency_to(CompileLog* log,
433 DepType dept,
434 GrowableArray<DepArgument>* args,
435 Klass* witness) {
436 if (log == NULL) {
437 return;
438 }
439 ResourceMark rm;
440 ciEnv* env = ciEnv::current();
441 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
442 for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
443 DepArgument arg = *it;
444 if (arg.is_oop()) {
445 ciargs->push(env->get_object(arg.oop_value()));
446 } else {
447 ciargs->push(env->get_metadata(arg.metadata_value()));
448 }
449 }
450 int argslen = ciargs->length();
451 Dependencies::write_dependency_to(log, dept, ciargs, witness);
452 guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
453 }
454
455 void Dependencies::write_dependency_to(CompileLog* log,
456 DepType dept,
457 GrowableArray<ciBaseObject*>* args,
458 Klass* witness) {
459 if (log == NULL) {
460 return;
461 }
462 ResourceMark rm;
463 GrowableArray<int>* argids = new GrowableArray<int>(args->length());
464 for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
465 ciBaseObject* obj = *it;
466 if (obj->is_object()) {
467 argids->push(log->identify(obj->as_object()));
468 } else {
469 argids->push(log->identify(obj->as_metadata()));
470 }
471 }
472 if (witness != NULL) {
473 log->begin_elem("dependency_failed");
474 } else {
475 log->begin_elem("dependency");
476 }
477 log->print(" type='%s'", dep_name(dept));
478 const int ctxkj = dep_context_arg(dept); // -1 if no context arg
479 if (ctxkj >= 0 && ctxkj < argids->length()) {
480 log->print(" ctxk='%d'", argids->at(ctxkj));
481 }
482 // write remaining arguments, if any.
483 for (int j = 0; j < argids->length(); j++) {
484 if (j == ctxkj) continue; // already logged
485 if (j == 1) {
486 log->print( " x='%d'", argids->at(j));
487 } else {
488 log->print(" x%d='%d'", j, argids->at(j));
489 }
490 }
491 if (witness != NULL) {
492 log->object("witness", witness);
493 log->stamp();
494 }
495 log->end_elem();
496 }
497
498 void Dependencies::write_dependency_to(xmlStream* xtty,
499 DepType dept,
500 GrowableArray<DepArgument>* args,
501 Klass* witness) {
502 if (xtty == NULL) {
503 return;
504 }
505 ResourceMark rm;
506 ttyLocker ttyl;
507 int ctxkj = dep_context_arg(dept); // -1 if no context arg
508 if (witness != NULL) {
509 xtty->begin_elem("dependency_failed");
510 } else {
511 xtty->begin_elem("dependency");
512 }
513 xtty->print(" type='%s'", dep_name(dept));
514 if (ctxkj >= 0) {
515 xtty->object("ctxk", args->at(ctxkj).metadata_value());
516 }
517 // write remaining arguments, if any.
518 for (int j = 0; j < args->length(); j++) {
519 if (j == ctxkj) continue; // already logged
520 DepArgument arg = args->at(j);
521 if (j == 1) {
522 if (arg.is_oop()) {
523 xtty->object("x", arg.oop_value());
524 } else {
525 xtty->object("x", arg.metadata_value());
526 }
527 } else {
528 char xn[10]; sprintf(xn, "x%d", j);
529 if (arg.is_oop()) {
530 xtty->object(xn, arg.oop_value());
531 } else {
532 xtty->object(xn, arg.metadata_value());
533 }
534 }
535 }
536 if (witness != NULL) {
537 xtty->object("witness", witness);
538 xtty->stamp();
539 }
540 xtty->end_elem();
541 }
542
543 void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
544 Klass* witness) {
545 ResourceMark rm;
546 ttyLocker ttyl; // keep the following output all in one block
547 tty->print_cr("%s of type %s",
548 (witness == NULL)? "Dependency": "Failed dependency",
549 dep_name(dept));
550 // print arguments
551 int ctxkj = dep_context_arg(dept); // -1 if no context arg
552 for (int j = 0; j < args->length(); j++) {
553 DepArgument arg = args->at(j);
554 bool put_star = false;
555 if (arg.is_null()) continue;
556 const char* what;
557 if (j == ctxkj) {
558 assert(arg.is_metadata(), "must be");
559 what = "context";
560 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
561 } else if (arg.is_method()) {
562 what = "method ";
563 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
564 } else if (arg.is_klass()) {
565 what = "class ";
566 } else {
567 what = "object ";
568 }
569 tty->print(" %s = %s", what, (put_star? "*": ""));
570 if (arg.is_klass()) {
571 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
572 } else if (arg.is_method()) {
573 ((Method*)arg.metadata_value())->print_value();
574 } else if (arg.is_oop()) {
575 arg.oop_value()->print_value_on(tty);
576 } else {
577 ShouldNotReachHere(); // Provide impl for this type.
578 }
579
580 tty->cr();
581 }
582 if (witness != NULL) {
583 bool put_star = !Dependencies::is_concrete_klass(witness);
584 tty->print_cr(" witness = %s%s",
585 (put_star? "*": ""),
586 witness->external_name());
587 }
588 }
589
590 void Dependencies::DepStream::log_dependency(Klass* witness) {
591 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
592 ResourceMark rm;
593 const int nargs = argument_count();
594 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
595 for (int j = 0; j < nargs; j++) {
596 if (type() == call_site_target_value) {
597 args->push(argument_oop(j));
598 } else {
599 args->push(argument(j));
600 }
601 }
602 int argslen = args->length();
603 if (_deps != NULL && _deps->log() != NULL) {
604 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
605 } else {
606 Dependencies::write_dependency_to(xtty, type(), args, witness);
607 }
608 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
609 }
610
611 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
612 ResourceMark rm;
613 int nargs = argument_count();
614 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
615 for (int j = 0; j < nargs; j++) {
616 if (type() == call_site_target_value) {
617 args->push(argument_oop(j));
618 } else {
619 args->push(argument(j));
620 }
621 }
622 int argslen = args->length();
623 Dependencies::print_dependency(type(), args, witness);
624 if (verbose) {
625 if (_code != NULL) {
626 tty->print(" code: ");
627 _code->print_value_on(tty);
628 tty->cr();
629 }
630 }
631 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
632 }
633
634
635 /// Dependency stream support (decodes dependencies from an nmethod):
636
637 #ifdef ASSERT
638 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
639 assert(must_be_in_vm(), "raw oops here");
640 _byte_limit = byte_limit;
641 _type = (DepType)(end_marker-1); // defeat "already at end" assert
642 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
643 }
644 #endif //ASSERT
645
646 bool Dependencies::DepStream::next() {
647 assert(_type != end_marker, "already at end");
648 if (_bytes.position() == 0 && _code != NULL
649 && _code->dependencies_size() == 0) {
650 // Method has no dependencies at all.
651 return false;
652 }
653 int code_byte = (_bytes.read_byte() & 0xFF);
654 if (code_byte == end_marker) {
655 DEBUG_ONLY(_type = end_marker);
656 return false;
657 } else {
658 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
659 code_byte -= ctxk_bit;
660 DepType dept = (DepType)code_byte;
661 _type = dept;
662 Dependencies::check_valid_dependency_type(dept);
663 int stride = _dep_args[dept];
664 assert(stride == dep_args(dept), "sanity");
665 int skipj = -1;
666 if (ctxk_bit != 0) {
667 skipj = 0; // currently the only context argument is at zero
668 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
669 }
670 for (int j = 0; j < stride; j++) {
671 _xi[j] = (j == skipj)? 0: _bytes.read_int();
672 }
673 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
674 return true;
675 }
676 }
677
678 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
679 Metadata* o = NULL;
680 if (_code != NULL) {
681 o = _code->metadata_at(i);
682 } else {
683 o = _deps->oop_recorder()->metadata_at(i);
684 }
685 return o;
686 }
687
688 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
689 return (_code != NULL)
690 ? _code->oop_at(i)
691 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
692 }
693
694 Metadata* Dependencies::DepStream::argument(int i) {
695 Metadata* result = recorded_metadata_at(argument_index(i));
696
697 if (result == NULL) { // Explicit context argument can be compressed
698 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
699 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
700 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
701 }
702 }
703
704 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
705 return result;
706 }
707
708 /**
709 * Returns a unique identifier for each dependency argument.
710 */
711 uintptr_t Dependencies::DepStream::get_identifier(int i) {
712 if (has_oop_argument()) {
713 return (uintptr_t)(oopDesc*)argument_oop(i);
714 } else {
715 return (uintptr_t)argument(i);
716 }
717 }
718
719 oop Dependencies::DepStream::argument_oop(int i) {
720 oop result = recorded_oop_at(argument_index(i));
721 assert(result == NULL || result->is_oop(), "must be");
722 return result;
723 }
724
725 Klass* Dependencies::DepStream::context_type() {
726 assert(must_be_in_vm(), "raw oops here");
727
728 // Most dependencies have an explicit context type argument.
729 {
730 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
731 if (ctxkj >= 0) {
732 Metadata* k = argument(ctxkj);
733 assert(k != NULL && k->is_klass(), "type check");
734 return (Klass*)k;
735 }
736 }
737
738 // Some dependencies are using the klass of the first object
739 // argument as implicit context type (e.g. call_site_target_value).
740 {
741 int ctxkj = dep_implicit_context_arg(type());
742 if (ctxkj >= 0) {
743 Klass* k = argument_oop(ctxkj)->klass();
744 assert(k != NULL && k->is_klass(), "type check");
745 return (Klass*) k;
746 }
747 }
748
749 // And some dependencies don't have a context type at all,
750 // e.g. evol_method.
751 return NULL;
752 }
753
754 // ----------------- DependencySignature --------------------------------------
755 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
756 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
757 return false;
758 }
759
760 for (int i = 0; i < s1.args_count(); i++) {
761 if (s1.arg(i) != s2.arg(i)) {
762 return false;
763 }
764 }
765 return true;
766 }
767
768 /// Checking dependencies:
769
770 // This hierarchy walker inspects subtypes of a given type,
771 // trying to find a "bad" class which breaks a dependency.
772 // Such a class is called a "witness" to the broken dependency.
773 // While searching around, we ignore "participants", which
774 // are already known to the dependency.
775 class ClassHierarchyWalker {
776 public:
777 enum { PARTICIPANT_LIMIT = 3 };
778
779 private:
780 // optional method descriptor to check for:
781 Symbol* _name;
782 Symbol* _signature;
783
784 // special classes which are not allowed to be witnesses:
785 Klass* _participants[PARTICIPANT_LIMIT+1];
786 int _num_participants;
787
788 // cache of method lookups
789 Method* _found_methods[PARTICIPANT_LIMIT+1];
790
791 // if non-zero, tells how many witnesses to convert to participants
792 int _record_witnesses;
793
794 void initialize(Klass* participant) {
795 _record_witnesses = 0;
796 _participants[0] = participant;
797 _found_methods[0] = NULL;
798 _num_participants = 0;
799 if (participant != NULL) {
800 // Terminating NULL.
801 _participants[1] = NULL;
802 _found_methods[1] = NULL;
803 _num_participants = 1;
804 }
805 }
806
807 void initialize_from_method(Method* m) {
808 assert(m != NULL && m->is_method(), "sanity");
809 _name = m->name();
810 _signature = m->signature();
811 }
812
813 public:
814 // The walker is initialized to recognize certain methods and/or types
815 // as friendly participants.
816 ClassHierarchyWalker(Klass* participant, Method* m) {
817 initialize_from_method(m);
818 initialize(participant);
819 }
820 ClassHierarchyWalker(Method* m) {
821 initialize_from_method(m);
822 initialize(NULL);
823 }
824 ClassHierarchyWalker(Klass* participant = NULL) {
825 _name = NULL;
826 _signature = NULL;
827 initialize(participant);
828 }
829
830 // This is common code for two searches: One for concrete subtypes,
831 // the other for concrete method implementations and overrides.
832 bool doing_subtype_search() {
833 return _name == NULL;
834 }
835
836 int num_participants() { return _num_participants; }
837 Klass* participant(int n) {
838 assert((uint)n <= (uint)_num_participants, "oob");
839 return _participants[n];
840 }
841
842 // Note: If n==num_participants, returns NULL.
843 Method* found_method(int n) {
844 assert((uint)n <= (uint)_num_participants, "oob");
845 Method* fm = _found_methods[n];
846 assert(n == _num_participants || fm != NULL, "proper usage");
847 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
848 return fm;
849 }
850
851 #ifdef ASSERT
852 // Assert that m is inherited into ctxk, without intervening overrides.
853 // (May return true even if this is not true, in corner cases where we punt.)
854 bool check_method_context(Klass* ctxk, Method* m) {
855 if (m->method_holder() == ctxk)
856 return true; // Quick win.
857 if (m->is_private())
858 return false; // Quick lose. Should not happen.
859 if (!(m->is_public() || m->is_protected()))
860 // The override story is complex when packages get involved.
861 return true; // Must punt the assertion to true.
862 Klass* k = ctxk;
863 Method* lm = k->lookup_method(m->name(), m->signature());
864 if (lm == NULL && k->oop_is_instance()) {
865 // It might be an interface method
866 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
867 m->signature());
868 }
869 if (lm == m)
870 // Method m is inherited into ctxk.
871 return true;
872 if (lm != NULL) {
873 if (!(lm->is_public() || lm->is_protected())) {
874 // Method is [package-]private, so the override story is complex.
875 return true; // Must punt the assertion to true.
876 }
877 if (lm->is_static()) {
878 // Static methods don't override non-static so punt
879 return true;
880 }
881 if ( !Dependencies::is_concrete_method(lm)
882 && !Dependencies::is_concrete_method(m)
883 && lm->method_holder()->is_subtype_of(m->method_holder()))
884 // Method m is overridden by lm, but both are non-concrete.
885 return true;
886 }
887 ResourceMark rm;
888 tty->print_cr("Dependency method not found in the associated context:");
889 tty->print_cr(" context = %s", ctxk->external_name());
890 tty->print( " method = "); m->print_short_name(tty); tty->cr();
891 if (lm != NULL) {
892 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
893 }
894 return false;
895 }
896 #endif
897
898 void add_participant(Klass* participant) {
899 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
900 int np = _num_participants++;
901 _participants[np] = participant;
902 _participants[np+1] = NULL;
903 _found_methods[np+1] = NULL;
904 }
905
906 void record_witnesses(int add) {
907 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
908 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
909 _record_witnesses = add;
910 }
911
912 bool is_witness(Klass* k) {
913 if (doing_subtype_search()) {
914 return Dependencies::is_concrete_klass(k);
915 } else {
916 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
917 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
918 _found_methods[_num_participants] = m;
919 // Note: If add_participant(k) is called,
920 // the method m will already be memoized for it.
921 return true;
922 }
923 }
924
925 bool is_participant(Klass* k) {
926 if (k == _participants[0]) {
927 return true;
928 } else if (_num_participants <= 1) {
929 return false;
930 } else {
931 return in_list(k, &_participants[1]);
932 }
933 }
934 bool ignore_witness(Klass* witness) {
935 if (_record_witnesses == 0) {
936 return false;
937 } else {
938 --_record_witnesses;
939 add_participant(witness);
940 return true;
941 }
942 }
943 static bool in_list(Klass* x, Klass** list) {
944 for (int i = 0; ; i++) {
945 Klass* y = list[i];
946 if (y == NULL) break;
947 if (y == x) return true;
948 }
949 return false; // not in list
950 }
951
952 private:
953 // the actual search method:
954 Klass* find_witness_anywhere(Klass* context_type,
955 bool participants_hide_witnesses,
956 bool top_level_call = true);
957 // the spot-checking version:
958 Klass* find_witness_in(KlassDepChange& changes,
959 Klass* context_type,
960 bool participants_hide_witnesses);
961 public:
962 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
963 assert(doing_subtype_search(), "must set up a subtype search");
964 // When looking for unexpected concrete types,
965 // do not look beneath expected ones.
966 const bool participants_hide_witnesses = true;
967 // CX > CC > C' is OK, even if C' is new.
968 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
969 if (changes != NULL) {
970 return find_witness_in(*changes, context_type, participants_hide_witnesses);
971 } else {
972 return find_witness_anywhere(context_type, participants_hide_witnesses);
973 }
974 }
975 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
976 assert(!doing_subtype_search(), "must set up a method definer search");
977 // When looking for unexpected concrete methods,
978 // look beneath expected ones, to see if there are overrides.
979 const bool participants_hide_witnesses = true;
980 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
981 if (changes != NULL) {
982 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
983 } else {
984 return find_witness_anywhere(context_type, !participants_hide_witnesses);
985 }
986 }
987 };
988
989 #ifndef PRODUCT
990 static int deps_find_witness_calls = 0;
991 static int deps_find_witness_steps = 0;
992 static int deps_find_witness_recursions = 0;
993 static int deps_find_witness_singles = 0;
994 static int deps_find_witness_print = 0; // set to -1 to force a final print
995 static bool count_find_witness_calls() {
996 if (TraceDependencies || LogCompilation) {
997 int pcount = deps_find_witness_print + 1;
998 bool final_stats = (pcount == 0);
999 bool initial_call = (pcount == 1);
1000 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
1001 if (pcount < 0) pcount = 1; // crude overflow protection
1002 deps_find_witness_print = pcount;
1003 if (VerifyDependencies && initial_call) {
1004 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
1005 }
1006 if (occasional_print || final_stats) {
1007 // Every now and then dump a little info about dependency searching.
1008 if (xtty != NULL) {
1009 ttyLocker ttyl;
1010 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
1011 deps_find_witness_calls,
1012 deps_find_witness_steps,
1013 deps_find_witness_recursions,
1014 deps_find_witness_singles);
1015 }
1016 if (final_stats || (TraceDependencies && WizardMode)) {
1017 ttyLocker ttyl;
1018 tty->print_cr("Dependency check (find_witness) "
1019 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
1020 deps_find_witness_calls,
1021 deps_find_witness_steps,
1022 (double)deps_find_witness_steps / deps_find_witness_calls,
1023 deps_find_witness_recursions,
1024 deps_find_witness_singles);
1025 }
1026 }
1027 return true;
1028 }
1029 return false;
1030 }
1031 #else
1032 #define count_find_witness_calls() (0)
1033 #endif //PRODUCT
1034
1035
1036 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1037 Klass* context_type,
1038 bool participants_hide_witnesses) {
1039 assert(changes.involves_context(context_type), "irrelevant dependency");
1040 Klass* new_type = changes.new_type();
1041
1042 (void)count_find_witness_calls();
1043 NOT_PRODUCT(deps_find_witness_singles++);
1044
1045 // Current thread must be in VM (not native mode, as in CI):
1046 assert(must_be_in_vm(), "raw oops here");
1047 // Must not move the class hierarchy during this check:
1048 assert_locked_or_safepoint(Compile_lock);
1049
1050 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1051 if (nof_impls > 1) {
1052 // Avoid this case: *I.m > { A.m, C }; B.m > C
1053 // %%% Until this is fixed more systematically, bail out.
1054 // See corresponding comment in find_witness_anywhere.
1055 return context_type;
1056 }
1057
1058 assert(!is_participant(new_type), "only old classes are participants");
1059 if (participants_hide_witnesses) {
1060 // If the new type is a subtype of a participant, we are done.
1061 for (int i = 0; i < num_participants(); i++) {
1062 Klass* part = participant(i);
1063 if (part == NULL) continue;
1064 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1065 "correct marking of participants, b/c new_type is unique");
1066 if (changes.involves_context(part)) {
1067 // new guy is protected from this check by previous participant
1068 return NULL;
1069 }
1070 }
1071 }
1072
1073 if (is_witness(new_type) &&
1074 !ignore_witness(new_type)) {
1075 return new_type;
1076 }
1077
1078 return NULL;
1079 }
1080
1081
1082 // Walk hierarchy under a context type, looking for unexpected types.
1083 // Do not report participant types, and recursively walk beneath
1084 // them only if participants_hide_witnesses is false.
1085 // If top_level_call is false, skip testing the context type,
1086 // because the caller has already considered it.
1087 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1088 bool participants_hide_witnesses,
1089 bool top_level_call) {
1090 // Current thread must be in VM (not native mode, as in CI):
1091 assert(must_be_in_vm(), "raw oops here");
1092 // Must not move the class hierarchy during this check:
1093 assert_locked_or_safepoint(Compile_lock);
1094
1095 bool do_counts = count_find_witness_calls();
1096
1097 // Check the root of the sub-hierarchy first.
1098 if (top_level_call) {
1099 if (do_counts) {
1100 NOT_PRODUCT(deps_find_witness_calls++);
1101 NOT_PRODUCT(deps_find_witness_steps++);
1102 }
1103 if (is_participant(context_type)) {
1104 if (participants_hide_witnesses) return NULL;
1105 // else fall through to search loop...
1106 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1107 // The context is an abstract class or interface, to start with.
1108 return context_type;
1109 }
1110 }
1111
1112 // Now we must check each implementor and each subclass.
1113 // Use a short worklist to avoid blowing the stack.
1114 // Each worklist entry is a *chain* of subklass siblings to process.
1115 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1116 Klass* chains[CHAINMAX];
1117 int chaini = 0; // index into worklist
1118 Klass* chain; // scratch variable
1119 #define ADD_SUBCLASS_CHAIN(k) { \
1120 assert(chaini < CHAINMAX, "oob"); \
1121 chain = InstanceKlass::cast(k)->subklass(); \
1122 if (chain != NULL) chains[chaini++] = chain; }
1123
1124 // Look for non-abstract subclasses.
1125 // (Note: Interfaces do not have subclasses.)
1126 ADD_SUBCLASS_CHAIN(context_type);
1127
1128 // If it is an interface, search its direct implementors.
1129 // (Their subclasses are additional indirect implementors.
1130 // See InstanceKlass::add_implementor.)
1131 // (Note: nof_implementors is always zero for non-interfaces.)
1132 if (top_level_call) {
1133 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1134 if (nof_impls > 1) {
1135 // Avoid this case: *I.m > { A.m, C }; B.m > C
1136 // Here, I.m has 2 concrete implementations, but m appears unique
1137 // as A.m, because the search misses B.m when checking C.
1138 // The inherited method B.m was getting missed by the walker
1139 // when interface 'I' was the starting point.
1140 // %%% Until this is fixed more systematically, bail out.
1141 // (Old CHA had the same limitation.)
1142 return context_type;
1143 }
1144 if (nof_impls > 0) {
1145 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1146 assert(impl != NULL, "just checking");
1147 // If impl is the same as the context_type, then more than one
1148 // implementor has seen. No exact info in this case.
1149 if (impl == context_type) {
1150 return context_type; // report an inexact witness to this sad affair
1151 }
1152 if (do_counts)
1153 { NOT_PRODUCT(deps_find_witness_steps++); }
1154 if (is_participant(impl)) {
1155 if (!participants_hide_witnesses) {
1156 ADD_SUBCLASS_CHAIN(impl);
1157 }
1158 } else if (is_witness(impl) && !ignore_witness(impl)) {
1159 return impl;
1160 } else {
1161 ADD_SUBCLASS_CHAIN(impl);
1162 }
1163 }
1164 }
1165
1166 // Recursively process each non-trivial sibling chain.
1167 while (chaini > 0) {
1168 Klass* chain = chains[--chaini];
1169 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1170 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1171 if (!sub->oop_is_instance()) {
1172 // This may happen for Klass java.lang.Object because it is a superclass
1173 // of all other Klasses including non-instance Klasses like ObjArrayKlass.
1174 continue;
1175 }
1176 if (is_participant(sub)) {
1177 if (participants_hide_witnesses) continue;
1178 // else fall through to process this guy's subclasses
1179 } else if (is_witness(sub) && !ignore_witness(sub)) {
1180 return sub;
1181 }
1182 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1183 // Fast path. (Partially disabled if VerifyDependencies.)
1184 ADD_SUBCLASS_CHAIN(sub);
1185 } else {
1186 // Worklist overflow. Do a recursive call. Should be rare.
1187 // The recursive call will have its own worklist, of course.
1188 // (Note that sub has already been tested, so that there is
1189 // no need for the recursive call to re-test. That's handy,
1190 // since the recursive call sees sub as the context_type.)
1191 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1192 Klass* witness = find_witness_anywhere(sub,
1193 participants_hide_witnesses,
1194 /*top_level_call=*/ false);
1195 if (witness != NULL) return witness;
1196 }
1197 }
1198 }
1199
1200 // No witness found. The dependency remains unbroken.
1201 return NULL;
1202 #undef ADD_SUBCLASS_CHAIN
1203 }
1204
1205
1206 bool Dependencies::is_concrete_klass(Klass* k) {
1207 if (k->is_abstract()) return false;
1208 // %%% We could treat classes which are concrete but
1209 // have not yet been instantiated as virtually abstract.
1210 // This would require a deoptimization barrier on first instantiation.
1211 //if (k->is_not_instantiated()) return false;
1212 return true;
1213 }
1214
1215 bool Dependencies::is_concrete_method(Method* m) {
1216 // Statics are irrelevant to virtual call sites.
1217 if (m->is_static()) return false;
1218
1219 // We could also return false if m does not yet appear to be
1220 // executed, if the VM version supports this distinction also.
1221 // Default methods are considered "concrete" as well.
1222 return !m->is_abstract() &&
1223 !m->is_overpass(); // error functions aren't concrete
1224 }
1225
1226
1227 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1228 if (k->is_interface()) return NULL;
1229 if (k->has_finalizer()) return k;
1230 k = k->subklass();
1231 while (k != NULL) {
1232 Klass* result = find_finalizable_subclass(k);
1233 if (result != NULL) return result;
1234 k = k->next_sibling();
1235 }
1236 return NULL;
1237 }
1238
1239
1240 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1241 if (k->is_abstract()) return false;
1242 // We could also return false if k does not yet appear to be
1243 // instantiated, if the VM version supports this distinction also.
1244 //if (k->is_not_instantiated()) return false;
1245 return true;
1246 }
1247
1248 bool Dependencies::is_concrete_method(ciMethod* m) {
1249 // Statics are irrelevant to virtual call sites.
1250 if (m->is_static()) return false;
1251
1252 // We could also return false if m does not yet appear to be
1253 // executed, if the VM version supports this distinction also.
1254 return !m->is_abstract();
1255 }
1256
1257
1258 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1259 return k->has_finalizable_subclass();
1260 }
1261
1262
1263 // Any use of the contents (bytecodes) of a method must be
1264 // marked by an "evol_method" dependency, if those contents
1265 // can change. (Note: A method is always dependent on itself.)
1266 Klass* Dependencies::check_evol_method(Method* m) {
1267 assert(must_be_in_vm(), "raw oops here");
1268 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1269 // Or is there a now a breakpoint?
1270 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1271 if (m->is_old()
1272 || m->number_of_breakpoints() > 0) {
1273 return m->method_holder();
1274 } else {
1275 return NULL;
1276 }
1277 }
1278
1279 // This is a strong assertion: It is that the given type
1280 // has no subtypes whatever. It is most useful for
1281 // optimizing checks on reflected types or on array types.
1282 // (Checks on types which are derived from real instances
1283 // can be optimized more strongly than this, because we
1284 // know that the checked type comes from a concrete type,
1285 // and therefore we can disregard abstract types.)
1286 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1287 assert(must_be_in_vm(), "raw oops here");
1288 assert_locked_or_safepoint(Compile_lock);
1289 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1290 Klass* sub = ctx->subklass();
1291 if (sub != NULL) {
1292 return sub;
1293 } else if (ctx->nof_implementors() != 0) {
1294 // if it is an interface, it must be unimplemented
1295 // (if it is not an interface, nof_implementors is always zero)
1296 Klass* impl = ctx->implementor();
1297 assert(impl != NULL, "must be set");
1298 return impl;
1299 } else {
1300 return NULL;
1301 }
1302 }
1303
1304 // Test the assertion that conck is the only concrete subtype* of ctxk.
1305 // The type conck itself is allowed to have have further concrete subtypes.
1306 // This allows the compiler to narrow occurrences of ctxk by conck,
1307 // when dealing with the types of actual instances.
1308 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1309 Klass* conck,
1310 KlassDepChange* changes) {
1311 ClassHierarchyWalker wf(conck);
1312 return wf.find_witness_subtype(ctxk, changes);
1313 }
1314
1315 // If a non-concrete class has no concrete subtypes, it is not (yet)
1316 // instantiatable. This can allow the compiler to make some paths go
1317 // dead, if they are gated by a test of the type.
1318 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1319 KlassDepChange* changes) {
1320 // Find any concrete subtype, with no participants:
1321 ClassHierarchyWalker wf;
1322 return wf.find_witness_subtype(ctxk, changes);
1323 }
1324
1325
1326 // If a concrete class has no concrete subtypes, it can always be
1327 // exactly typed. This allows the use of a cheaper type test.
1328 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1329 KlassDepChange* changes) {
1330 // Find any concrete subtype, with only the ctxk as participant:
1331 ClassHierarchyWalker wf(ctxk);
1332 return wf.find_witness_subtype(ctxk, changes);
1333 }
1334
1335
1336 // Find the unique concrete proper subtype of ctxk, or NULL if there
1337 // is more than one concrete proper subtype. If there are no concrete
1338 // proper subtypes, return ctxk itself, whether it is concrete or not.
1339 // The returned subtype is allowed to have have further concrete subtypes.
1340 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1341 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1342 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1343 wf.record_witnesses(1); // Record one other witness when walking.
1344 Klass* wit = wf.find_witness_subtype(ctxk);
1345 if (wit != NULL) return NULL; // Too many witnesses.
1346 Klass* conck = wf.participant(0);
1347 if (conck == NULL) {
1348 #ifndef PRODUCT
1349 // Make sure the dependency mechanism will pass this discovery:
1350 if (VerifyDependencies) {
1351 // Turn off dependency tracing while actually testing deps.
1352 FlagSetting fs(TraceDependencies, false);
1353 if (!Dependencies::is_concrete_klass(ctxk)) {
1354 guarantee(NULL ==
1355 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1356 "verify dep.");
1357 } else {
1358 guarantee(NULL ==
1359 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1360 "verify dep.");
1361 }
1362 }
1363 #endif //PRODUCT
1364 return ctxk; // Return ctxk as a flag for "no subtypes".
1365 } else {
1366 #ifndef PRODUCT
1367 // Make sure the dependency mechanism will pass this discovery:
1368 if (VerifyDependencies) {
1369 // Turn off dependency tracing while actually testing deps.
1370 FlagSetting fs(TraceDependencies, false);
1371 if (!Dependencies::is_concrete_klass(ctxk)) {
1372 guarantee(NULL == (void *)
1373 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1374 "verify dep.");
1375 }
1376 }
1377 #endif //PRODUCT
1378 return conck;
1379 }
1380 }
1381
1382 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1383 // except possibly for further subtypes of k[12] themselves.
1384 // The context type must be abstract. The types k1 and k2 are themselves
1385 // allowed to have further concrete subtypes.
1386 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1387 Klass* ctxk,
1388 Klass* k1,
1389 Klass* k2,
1390 KlassDepChange* changes) {
1391 ClassHierarchyWalker wf;
1392 wf.add_participant(k1);
1393 wf.add_participant(k2);
1394 return wf.find_witness_subtype(ctxk, changes);
1395 }
1396
1397 // Search ctxk for concrete implementations. If there are klen or fewer,
1398 // pack them into the given array and return the number.
1399 // Otherwise, return -1, meaning the given array would overflow.
1400 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1401 // In this search, if ctxk is concrete, it will be reported alone.
1402 // For any type CC reported, no proper subtypes of CC will be reported.
1403 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1404 int klen,
1405 Klass* karray[]) {
1406 ClassHierarchyWalker wf;
1407 wf.record_witnesses(klen);
1408 Klass* wit = wf.find_witness_subtype(ctxk);
1409 if (wit != NULL) return -1; // Too many witnesses.
1410 int num = wf.num_participants();
1411 assert(num <= klen, "oob");
1412 // Pack the result array with the good news.
1413 for (int i = 0; i < num; i++)
1414 karray[i] = wf.participant(i);
1415 #ifndef PRODUCT
1416 // Make sure the dependency mechanism will pass this discovery:
1417 if (VerifyDependencies) {
1418 // Turn off dependency tracing while actually testing deps.
1419 FlagSetting fs(TraceDependencies, false);
1420 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1421 case -1: // ctxk was itself concrete
1422 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1423 break;
1424 case 0:
1425 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1426 "verify dep.");
1427 break;
1428 case 1:
1429 guarantee(NULL == (void *)
1430 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1431 "verify dep.");
1432 break;
1433 case 2:
1434 guarantee(NULL == (void *)
1435 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1436 karray[0],
1437 karray[1]),
1438 "verify dep.");
1439 break;
1440 default:
1441 ShouldNotReachHere(); // klen > 2 yet supported
1442 }
1443 }
1444 #endif //PRODUCT
1445 return num;
1446 }
1447
1448 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1449 // Otherwise, return a class that contains an interfering method.
1450 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1451 KlassDepChange* changes) {
1452 // Here is a missing optimization: If uniqm->is_final(),
1453 // we don't really need to search beneath it for overrides.
1454 // This is probably not important, since we don't use dependencies
1455 // to track final methods. (They can't be "definalized".)
1456 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1457 return wf.find_witness_definer(ctxk, changes);
1458 }
1459
1460 // Find the set of all non-abstract methods under ctxk that match m.
1461 // (The method m must be defined or inherited in ctxk.)
1462 // Include m itself in the set, unless it is abstract.
1463 // If this set has exactly one element, return that element.
1464 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1465 // Return NULL if m is marked old; must have been a redefined method.
1466 if (m->is_old()) {
1467 return NULL;
1468 }
1469 ClassHierarchyWalker wf(m);
1470 assert(wf.check_method_context(ctxk, m), "proper context");
1471 wf.record_witnesses(1);
1472 Klass* wit = wf.find_witness_definer(ctxk);
1473 if (wit != NULL) return NULL; // Too many witnesses.
1474 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1475 if (Dependencies::is_concrete_method(m)) {
1476 if (fm == NULL) {
1477 // It turns out that m was always the only implementation.
1478 fm = m;
1479 } else if (fm != m) {
1480 // Two conflicting implementations after all.
1481 // (This can happen if m is inherited into ctxk and fm overrides it.)
1482 return NULL;
1483 }
1484 }
1485 #ifndef PRODUCT
1486 // Make sure the dependency mechanism will pass this discovery:
1487 if (VerifyDependencies && fm != NULL) {
1488 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1489 "verify dep.");
1490 }
1491 #endif //PRODUCT
1492 return fm;
1493 }
1494
1495 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1496 Method* m1,
1497 Method* m2,
1498 KlassDepChange* changes) {
1499 ClassHierarchyWalker wf(m1);
1500 wf.add_participant(m1->method_holder());
1501 wf.add_participant(m2->method_holder());
1502 return wf.find_witness_definer(ctxk, changes);
1503 }
1504
1505 // Find the set of all non-abstract methods under ctxk that match m[0].
1506 // (The method m[0] must be defined or inherited in ctxk.)
1507 // Include m itself in the set, unless it is abstract.
1508 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1509 // (The length may be zero if no concrete methods are found anywhere.)
1510 // If there are too many concrete methods to fit in marray, return -1.
1511 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1512 int mlen,
1513 Method* marray[]) {
1514 Method* m0 = marray[0];
1515 ClassHierarchyWalker wf(m0);
1516 assert(wf.check_method_context(ctxk, m0), "proper context");
1517 wf.record_witnesses(mlen);
1518 bool participants_hide_witnesses = true;
1519 Klass* wit = wf.find_witness_definer(ctxk);
1520 if (wit != NULL) return -1; // Too many witnesses.
1521 int num = wf.num_participants();
1522 assert(num <= mlen, "oob");
1523 // Keep track of whether m is also part of the result set.
1524 int mfill = 0;
1525 assert(marray[mfill] == m0, "sanity");
1526 if (Dependencies::is_concrete_method(m0))
1527 mfill++; // keep m0 as marray[0], the first result
1528 for (int i = 0; i < num; i++) {
1529 Method* fm = wf.found_method(i);
1530 if (fm == m0) continue; // Already put this guy in the list.
1531 if (mfill == mlen) {
1532 return -1; // Oops. Too many methods after all!
1533 }
1534 marray[mfill++] = fm;
1535 }
1536 #ifndef PRODUCT
1537 // Make sure the dependency mechanism will pass this discovery:
1538 if (VerifyDependencies) {
1539 // Turn off dependency tracing while actually testing deps.
1540 FlagSetting fs(TraceDependencies, false);
1541 switch (mfill) {
1542 case 1:
1543 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1544 "verify dep.");
1545 break;
1546 case 2:
1547 guarantee(NULL == (void *)
1548 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1549 "verify dep.");
1550 break;
1551 default:
1552 ShouldNotReachHere(); // mlen > 2 yet supported
1553 }
1554 }
1555 #endif //PRODUCT
1556 return mfill;
1557 }
1558
1559
1560 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1561 Klass* search_at = ctxk;
1562 if (changes != NULL)
1563 search_at = changes->new_type(); // just look at the new bit
1564 return find_finalizable_subclass(search_at);
1565 }
1566
1567
1568 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1569 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1570 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1571 if (changes == NULL) {
1572 // Validate all CallSites
1573 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1574 return call_site->klass(); // assertion failed
1575 } else {
1576 // Validate the given CallSite
1577 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1578 assert(method_handle != changes->method_handle(), "must be");
1579 return call_site->klass(); // assertion failed
1580 }
1581 }
1582 return NULL; // assertion still valid
1583 }
1584
1585
1586 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1587 if (witness != NULL) {
1588 if (TraceDependencies) {
1589 print_dependency(witness, /*verbose=*/ true);
1590 }
1591 // The following is a no-op unless logging is enabled:
1592 log_dependency(witness);
1593 }
1594 }
1595
1596
1597 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1598 assert_locked_or_safepoint(Compile_lock);
1599 Dependencies::check_valid_dependency_type(type());
1600
1601 Klass* witness = NULL;
1602 switch (type()) {
1603 case evol_method:
1604 witness = check_evol_method(method_argument(0));
1605 break;
1606 case leaf_type:
1607 witness = check_leaf_type(context_type());
1608 break;
1609 case abstract_with_unique_concrete_subtype:
1610 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1611 break;
1612 case abstract_with_no_concrete_subtype:
1613 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1614 break;
1615 case concrete_with_no_concrete_subtype:
1616 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1617 break;
1618 case unique_concrete_method:
1619 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1620 break;
1621 case abstract_with_exclusive_concrete_subtypes_2:
1622 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1623 break;
1624 case exclusive_concrete_methods_2:
1625 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1626 break;
1627 case no_finalizable_subclasses:
1628 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1629 break;
1630 default:
1631 witness = NULL;
1632 break;
1633 }
1634 trace_and_log_witness(witness);
1635 return witness;
1636 }
1637
1638
1639 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1640 assert_locked_or_safepoint(Compile_lock);
1641 Dependencies::check_valid_dependency_type(type());
1642
1643 Klass* witness = NULL;
1644 switch (type()) {
1645 case call_site_target_value:
1646 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1647 break;
1648 default:
1649 witness = NULL;
1650 break;
1651 }
1652 trace_and_log_witness(witness);
1653 return witness;
1654 }
1655
1656
1657 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1658 // Handle klass dependency
1659 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1660 return check_klass_dependency(changes.as_klass_change());
1661
1662 // Handle CallSite dependency
1663 if (changes.is_call_site_change())
1664 return check_call_site_dependency(changes.as_call_site_change());
1665
1666 // irrelevant dependency; skip it
1667 return NULL;
1668 }
1669
1670
1671 void DepChange::print() {
1672 int nsup = 0, nint = 0;
1673 for (ContextStream str(*this); str.next(); ) {
1674 Klass* k = str.klass();
1675 switch (str.change_type()) {
1676 case Change_new_type:
1677 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1678 break;
1679 case Change_new_sub:
1680 if (!WizardMode) {
1681 ++nsup;
1682 } else {
1683 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1684 }
1685 break;
1686 case Change_new_impl:
1687 if (!WizardMode) {
1688 ++nint;
1689 } else {
1690 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1691 }
1692 break;
1693 }
1694 }
1695 if (nsup + nint != 0) {
1696 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1697 }
1698 }
1699
1700 void DepChange::ContextStream::start() {
1701 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1702 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1703 _klass = new_type;
1704 _ti_base = NULL;
1705 _ti_index = 0;
1706 _ti_limit = 0;
1707 }
1708
1709 bool DepChange::ContextStream::next() {
1710 switch (_change_type) {
1711 case Start_Klass: // initial state; _klass is the new type
1712 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1713 _ti_index = 0;
1714 _change_type = Change_new_type;
1715 return true;
1716 case Change_new_type:
1717 // fall through:
1718 _change_type = Change_new_sub;
1719 case Change_new_sub:
1720 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1721 {
1722 _klass = InstanceKlass::cast(_klass)->super();
1723 if (_klass != NULL) {
1724 return true;
1725 }
1726 }
1727 // else set up _ti_limit and fall through:
1728 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1729 _change_type = Change_new_impl;
1730 case Change_new_impl:
1731 if (_ti_index < _ti_limit) {
1732 _klass = _ti_base->at(_ti_index++);
1733 return true;
1734 }
1735 // fall through:
1736 _change_type = NO_CHANGE; // iterator is exhausted
1737 case NO_CHANGE:
1738 break;
1739 default:
1740 ShouldNotReachHere();
1741 }
1742 return false;
1743 }
1744
1745 void KlassDepChange::initialize() {
1746 // entire transaction must be under this lock:
1747 assert_lock_strong(Compile_lock);
1748
1749 // Mark all dependee and all its superclasses
1750 // Mark transitive interfaces
1751 for (ContextStream str(*this); str.next(); ) {
1752 Klass* d = str.klass();
1753 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1754 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1755 }
1756 }
1757
1758 KlassDepChange::~KlassDepChange() {
1759 // Unmark all dependee and all its superclasses
1760 // Unmark transitive interfaces
1761 for (ContextStream str(*this); str.next(); ) {
1762 Klass* d = str.klass();
1763 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1764 }
1765 }
1766
1767 bool KlassDepChange::involves_context(Klass* k) {
1768 if (k == NULL || !k->oop_is_instance()) {
1769 return false;
1770 }
1771 InstanceKlass* ik = InstanceKlass::cast(k);
1772 bool is_contained = ik->is_marked_dependent();
1773 assert(is_contained == new_type()->is_subtype_of(k),
1774 "correct marking of potential context types");
1775 return is_contained;
1776 }
1777
1778 #ifndef PRODUCT
1779 void Dependencies::print_statistics() {
1780 if (deps_find_witness_print != 0) {
1781 // Call one final time, to flush out the data.
1782 deps_find_witness_print = -1;
1783 count_find_witness_calls();
1784 }
1785 }
1786 #endif