1 /*
2 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
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 "classfile/javaClasses.inline.hpp"
31 #include "code/dependencies.hpp"
32 #include "compiler/compileLog.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/handles.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/thread.inline.hpp"
37 #include "utilities/copy.hpp"
38
39
40 #ifdef ASSERT
41 static bool must_be_in_vm() {
42 Thread* thread = Thread::current();
43 if (thread->is_Java_thread())
44 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
45 else
46 return true; //something like this: thread->is_VM_thread();
47 }
48 #endif //ASSERT
49
50 void Dependencies::initialize(ciEnv* env) {
51 Arena* arena = env->arena();
52 _oop_recorder = env->oop_recorder();
53 _log = env->log();
54 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
55 DEBUG_ONLY(_deps[end_marker] = NULL);
56 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
57 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
58 }
59 _content_bytes = NULL;
60 _size_in_bytes = (size_t)-1;
61
62 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
63 }
64
65 void Dependencies::assert_evol_method(ciMethod* m) {
66 assert_common_1(evol_method, m);
67 }
68
69 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
70 if (ctxk->is_array_klass()) {
71 // As a special case, support this assertion on an array type,
72 // which reduces to an assertion on its element type.
73 // Note that this cannot be done with assertions that
74 // relate to concreteness or abstractness.
75 ciType* elemt = ctxk->as_array_klass()->base_element_type();
76 if (!elemt->is_instance_klass()) return; // Ex: int[][]
77 ctxk = elemt->as_instance_klass();
78 //if (ctxk->is_final()) return; // Ex: String[][]
79 }
80 check_ctxk(ctxk);
81 assert_common_1(leaf_type, ctxk);
82 }
83
84 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
85 check_ctxk_abstract(ctxk);
86 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
87 }
88
89 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
90 check_ctxk_abstract(ctxk);
91 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
92 }
93
94 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
95 check_ctxk_concrete(ctxk);
96 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
97 }
98
99 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
100 check_ctxk(ctxk);
101 assert_common_2(unique_concrete_method, ctxk, uniqm);
102 }
103
104 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
105 check_ctxk(ctxk);
106 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
107 }
108
109 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
110 check_ctxk(ctxk);
111 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
112 }
113
114 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
115 check_ctxk(ctxk);
116 assert_common_1(no_finalizable_subclasses, ctxk);
117 }
118
119 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
120 ciKlass* ctxk = call_site->get_context();
121 check_ctxk(ctxk);
122 assert_common_3(call_site_target_value, ctxk, call_site, method_handle);
123 }
124
125 // Helper function. If we are adding a new dep. under ctxk2,
126 // try to find an old dep. under a broader* ctxk1. If there is
127 //
128 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
129 int ctxk_i, ciKlass* ctxk2) {
130 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
131 if (ctxk2->is_subtype_of(ctxk1)) {
132 return true; // success, and no need to change
133 } else if (ctxk1->is_subtype_of(ctxk2)) {
134 // new context class fully subsumes previous one
135 deps->at_put(ctxk_i, ctxk2);
136 return true;
137 } else {
138 return false;
139 }
140 }
141
142 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
143 assert(dep_args(dept) == 1, "sanity");
144 log_dependency(dept, x);
145 GrowableArray<ciBaseObject*>* deps = _deps[dept];
146
147 // see if the same (or a similar) dep is already recorded
148 if (note_dep_seen(dept, x)) {
149 assert(deps->find(x) >= 0, "sanity");
150 } else {
151 deps->append(x);
152 }
153 }
154
155 void Dependencies::assert_common_2(DepType dept,
156 ciBaseObject* x0, ciBaseObject* x1) {
157 assert(dep_args(dept) == 2, "sanity");
158 log_dependency(dept, x0, x1);
159 GrowableArray<ciBaseObject*>* deps = _deps[dept];
160
161 // see if the same (or a similar) dep is already recorded
162 bool has_ctxk = has_explicit_context_arg(dept);
163 if (has_ctxk) {
164 assert(dep_context_arg(dept) == 0, "sanity");
165 if (note_dep_seen(dept, x1)) {
166 // look in this bucket for redundant assertions
167 const int stride = 2;
168 for (int i = deps->length(); (i -= stride) >= 0; ) {
169 ciBaseObject* y1 = deps->at(i+1);
170 if (x1 == y1) { // same subject; check the context
171 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
172 return;
173 }
174 }
175 }
176 }
177 } else {
178 assert(dep_implicit_context_arg(dept) == 0, "sanity");
179 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
180 // look in this bucket for redundant assertions
181 const int stride = 2;
182 for (int i = deps->length(); (i -= stride) >= 0; ) {
183 ciBaseObject* y0 = deps->at(i+0);
184 ciBaseObject* y1 = deps->at(i+1);
185 if (x0 == y0 && x1 == y1) {
186 return;
187 }
188 }
189 }
190 }
191
192 // append the assertion in the correct bucket:
193 deps->append(x0);
194 deps->append(x1);
195 }
196
197 void Dependencies::assert_common_3(DepType dept,
198 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
199 assert(dep_context_arg(dept) == 0, "sanity");
200 assert(dep_args(dept) == 3, "sanity");
201 log_dependency(dept, ctxk, x, x2);
202 GrowableArray<ciBaseObject*>* deps = _deps[dept];
203
204 // try to normalize an unordered pair:
205 bool swap = false;
206 switch (dept) {
207 case abstract_with_exclusive_concrete_subtypes_2:
208 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
209 break;
210 case exclusive_concrete_methods_2:
211 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
212 break;
213 }
214 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
215
216 // see if the same (or a similar) dep is already recorded
217 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
218 // look in this bucket for redundant assertions
219 const int stride = 3;
220 for (int i = deps->length(); (i -= stride) >= 0; ) {
221 ciBaseObject* y = deps->at(i+1);
222 ciBaseObject* y2 = deps->at(i+2);
223 if (x == y && x2 == y2) { // same subjects; check the context
224 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
225 return;
226 }
227 }
228 }
229 }
230 // append the assertion in the correct bucket:
231 deps->append(ctxk);
232 deps->append(x);
233 deps->append(x2);
234 }
235
236 /// Support for encoding dependencies into an nmethod:
237
238 void Dependencies::copy_to(nmethod* nm) {
239 address beg = nm->dependencies_begin();
240 address end = nm->dependencies_end();
241 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
242 Copy::disjoint_words((HeapWord*) content_bytes(),
243 (HeapWord*) beg,
244 size_in_bytes() / sizeof(HeapWord));
245 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
246 }
247
248 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
249 for (int i = 0; i < narg; i++) {
250 int diff = p1[i]->ident() - p2[i]->ident();
251 if (diff != 0) return diff;
252 }
253 return 0;
254 }
255 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
256 { return sort_dep(p1, p2, 1); }
257 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
258 { return sort_dep(p1, p2, 2); }
259 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
260 { return sort_dep(p1, p2, 3); }
261
262 void Dependencies::sort_all_deps() {
263 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
264 DepType dept = (DepType)deptv;
265 GrowableArray<ciBaseObject*>* deps = _deps[dept];
266 if (deps->length() <= 1) continue;
267 switch (dep_args(dept)) {
268 case 1: deps->sort(sort_dep_arg_1, 1); break;
269 case 2: deps->sort(sort_dep_arg_2, 2); break;
270 case 3: deps->sort(sort_dep_arg_3, 3); break;
271 default: ShouldNotReachHere();
272 }
273 }
274 }
275
276 size_t Dependencies::estimate_size_in_bytes() {
277 size_t est_size = 100;
278 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
279 DepType dept = (DepType)deptv;
280 GrowableArray<ciBaseObject*>* deps = _deps[dept];
281 est_size += deps->length()*2; // tags and argument(s)
282 }
283 return est_size;
284 }
285
286 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
287 switch (dept) {
288 case abstract_with_exclusive_concrete_subtypes_2:
289 return x->as_metadata()->as_klass();
290 case unique_concrete_method:
291 case exclusive_concrete_methods_2:
292 return x->as_metadata()->as_method()->holder();
293 }
294 return NULL; // let NULL be NULL
295 }
296
297 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
298 assert(must_be_in_vm(), "raw oops here");
299 switch (dept) {
300 case abstract_with_exclusive_concrete_subtypes_2:
301 assert(x->is_klass(), "sanity");
302 return (Klass*) x;
303 case unique_concrete_method:
304 case exclusive_concrete_methods_2:
305 assert(x->is_method(), "sanity");
306 return ((Method*)x)->method_holder();
307 }
308 return NULL; // let NULL be NULL
309 }
310
311 void Dependencies::encode_content_bytes() {
312 sort_all_deps();
313
314 // cast is safe, no deps can overflow INT_MAX
315 CompressedWriteStream bytes((int)estimate_size_in_bytes());
316
317 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
318 DepType dept = (DepType)deptv;
319 GrowableArray<ciBaseObject*>* deps = _deps[dept];
320 if (deps->length() == 0) continue;
321 int stride = dep_args(dept);
322 int ctxkj = dep_context_arg(dept); // -1 if no context arg
323 assert(stride > 0, "sanity");
324 for (int i = 0; i < deps->length(); i += stride) {
325 jbyte code_byte = (jbyte)dept;
326 int skipj = -1;
327 if (ctxkj >= 0 && ctxkj+1 < stride) {
328 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
329 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
330 if (ctxk == ctxk_encoded_as_null(dept, x)) {
331 skipj = ctxkj; // we win: maybe one less oop to keep track of
332 code_byte |= default_context_type_bit;
333 }
334 }
335 bytes.write_byte(code_byte);
336 for (int j = 0; j < stride; j++) {
337 if (j == skipj) continue;
338 ciBaseObject* v = deps->at(i+j);
339 int idx;
340 if (v->is_object()) {
341 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
342 } else {
343 ciMetadata* meta = v->as_metadata();
344 idx = _oop_recorder->find_index(meta->constant_encoding());
345 }
346 bytes.write_int(idx);
347 }
348 }
349 }
350
351 // write a sentinel byte to mark the end
352 bytes.write_byte(end_marker);
353
354 // round it out to a word boundary
355 while (bytes.position() % sizeof(HeapWord) != 0) {
356 bytes.write_byte(end_marker);
357 }
358
359 // check whether the dept byte encoding really works
360 assert((jbyte)default_context_type_bit != 0, "byte overflow");
361
362 _content_bytes = bytes.buffer();
363 _size_in_bytes = bytes.position();
364 }
365
366
367 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
368 "end_marker",
369 "evol_method",
370 "leaf_type",
371 "abstract_with_unique_concrete_subtype",
372 "abstract_with_no_concrete_subtype",
373 "concrete_with_no_concrete_subtype",
374 "unique_concrete_method",
375 "abstract_with_exclusive_concrete_subtypes_2",
376 "exclusive_concrete_methods_2",
377 "no_finalizable_subclasses",
378 "call_site_target_value"
379 };
380
381 int Dependencies::_dep_args[TYPE_LIMIT] = {
382 -1,// end_marker
383 1, // evol_method m
384 1, // leaf_type ctxk
385 2, // abstract_with_unique_concrete_subtype ctxk, k
386 1, // abstract_with_no_concrete_subtype ctxk
387 1, // concrete_with_no_concrete_subtype ctxk
388 2, // unique_concrete_method ctxk, m
389 3, // unique_concrete_subtypes_2 ctxk, k1, k2
390 3, // unique_concrete_methods_2 ctxk, m1, m2
391 1, // no_finalizable_subclasses ctxk
392 3 // call_site_target_value ctxk, call_site, method_handle
393 };
394
395 const char* Dependencies::dep_name(Dependencies::DepType dept) {
396 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
397 return _dep_name[dept];
398 }
399
400 int Dependencies::dep_args(Dependencies::DepType dept) {
401 if (!dept_in_mask(dept, all_types)) return -1;
402 return _dep_args[dept];
403 }
404
405 void Dependencies::check_valid_dependency_type(DepType dept) {
406 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
407 }
408
409 // for the sake of the compiler log, print out current dependencies:
410 void Dependencies::log_all_dependencies() {
411 if (log() == NULL) return;
412 ResourceMark rm;
413 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
414 DepType dept = (DepType)deptv;
415 GrowableArray<ciBaseObject*>* deps = _deps[dept];
416 int deplen = deps->length();
417 if (deplen == 0) {
418 continue;
419 }
420 int stride = dep_args(dept);
421 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
422 for (int i = 0; i < deps->length(); i += stride) {
423 for (int j = 0; j < stride; j++) {
424 // flush out the identities before printing
425 ciargs->push(deps->at(i+j));
426 }
427 write_dependency_to(log(), dept, ciargs);
428 ciargs->clear();
429 }
430 guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
431 }
432 }
433
434 void Dependencies::write_dependency_to(CompileLog* log,
435 DepType dept,
436 GrowableArray<DepArgument>* args,
437 Klass* witness) {
438 if (log == NULL) {
439 return;
440 }
441 ResourceMark rm;
442 ciEnv* env = ciEnv::current();
443 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
444 for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
445 DepArgument arg = *it;
446 if (arg.is_oop()) {
447 ciargs->push(env->get_object(arg.oop_value()));
448 } else {
449 ciargs->push(env->get_metadata(arg.metadata_value()));
450 }
451 }
452 int argslen = ciargs->length();
453 Dependencies::write_dependency_to(log, dept, ciargs, witness);
454 guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
455 }
456
457 void Dependencies::write_dependency_to(CompileLog* log,
458 DepType dept,
459 GrowableArray<ciBaseObject*>* args,
460 Klass* witness) {
461 if (log == NULL) {
462 return;
463 }
464 ResourceMark rm;
465 GrowableArray<int>* argids = new GrowableArray<int>(args->length());
466 for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
467 ciBaseObject* obj = *it;
468 if (obj->is_object()) {
469 argids->push(log->identify(obj->as_object()));
470 } else {
471 argids->push(log->identify(obj->as_metadata()));
472 }
473 }
474 if (witness != NULL) {
475 log->begin_elem("dependency_failed");
476 } else {
477 log->begin_elem("dependency");
478 }
479 log->print(" type='%s'", dep_name(dept));
480 const int ctxkj = dep_context_arg(dept); // -1 if no context arg
481 if (ctxkj >= 0 && ctxkj < argids->length()) {
482 log->print(" ctxk='%d'", argids->at(ctxkj));
483 }
484 // write remaining arguments, if any.
485 for (int j = 0; j < argids->length(); j++) {
486 if (j == ctxkj) continue; // already logged
487 if (j == 1) {
488 log->print( " x='%d'", argids->at(j));
489 } else {
490 log->print(" x%d='%d'", j, argids->at(j));
491 }
492 }
493 if (witness != NULL) {
494 log->object("witness", witness);
495 log->stamp();
496 }
497 log->end_elem();
498 }
499
500 void Dependencies::write_dependency_to(xmlStream* xtty,
501 DepType dept,
502 GrowableArray<DepArgument>* args,
503 Klass* witness) {
504 if (xtty == NULL) {
505 return;
506 }
507 ResourceMark rm;
508 ttyLocker ttyl;
509 int ctxkj = dep_context_arg(dept); // -1 if no context arg
510 if (witness != NULL) {
511 xtty->begin_elem("dependency_failed");
512 } else {
513 xtty->begin_elem("dependency");
514 }
515 xtty->print(" type='%s'", dep_name(dept));
516 if (ctxkj >= 0) {
517 xtty->object("ctxk", args->at(ctxkj).metadata_value());
518 }
519 // write remaining arguments, if any.
520 for (int j = 0; j < args->length(); j++) {
521 if (j == ctxkj) continue; // already logged
522 DepArgument arg = args->at(j);
523 if (j == 1) {
524 if (arg.is_oop()) {
525 xtty->object("x", arg.oop_value());
526 } else {
527 xtty->object("x", arg.metadata_value());
528 }
529 } else {
530 char xn[10]; sprintf(xn, "x%d", j);
531 if (arg.is_oop()) {
532 xtty->object(xn, arg.oop_value());
533 } else {
534 xtty->object(xn, arg.metadata_value());
535 }
536 }
537 }
538 if (witness != NULL) {
539 xtty->object("witness", witness);
540 xtty->stamp();
541 }
542 xtty->end_elem();
543 }
544
545 void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
546 Klass* witness) {
547 ResourceMark rm;
548 ttyLocker ttyl; // keep the following output all in one block
549 tty->print_cr("%s of type %s",
550 (witness == NULL)? "Dependency": "Failed dependency",
551 dep_name(dept));
552 // print arguments
553 int ctxkj = dep_context_arg(dept); // -1 if no context arg
554 for (int j = 0; j < args->length(); j++) {
555 DepArgument arg = args->at(j);
556 bool put_star = false;
557 if (arg.is_null()) continue;
558 const char* what;
559 if (j == ctxkj) {
560 assert(arg.is_metadata(), "must be");
561 what = "context";
562 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
563 } else if (arg.is_method()) {
564 what = "method ";
565 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value(), NULL);
566 } else if (arg.is_klass()) {
567 what = "class ";
568 } else {
569 what = "object ";
570 }
571 tty->print(" %s = %s", what, (put_star? "*": ""));
572 if (arg.is_klass()) {
573 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
574 } else if (arg.is_method()) {
575 ((Method*)arg.metadata_value())->print_value();
576 } else if (arg.is_oop()) {
577 arg.oop_value()->print_value_on(tty);
578 } else {
579 ShouldNotReachHere(); // Provide impl for this type.
580 }
581
582 tty->cr();
583 }
584 if (witness != NULL) {
585 bool put_star = !Dependencies::is_concrete_klass(witness);
586 tty->print_cr(" witness = %s%s",
587 (put_star? "*": ""),
588 witness->external_name());
589 }
590 }
591
592 void Dependencies::DepStream::log_dependency(Klass* witness) {
593 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
594 ResourceMark rm;
595 const int nargs = argument_count();
596 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
597 for (int j = 0; j < nargs; j++) {
598 if (is_oop_argument(j)) {
599 args->push(argument_oop(j));
600 } else {
601 args->push(argument(j));
602 }
603 }
604 int argslen = args->length();
605 if (_deps != NULL && _deps->log() != NULL) {
606 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
607 } else {
608 Dependencies::write_dependency_to(xtty, type(), args, witness);
609 }
610 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
611 }
612
613 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
614 ResourceMark rm;
615 int nargs = argument_count();
616 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
617 for (int j = 0; j < nargs; j++) {
618 if (is_oop_argument(j)) {
619 args->push(argument_oop(j));
620 } else {
621 args->push(argument(j));
622 }
623 }
624 int argslen = args->length();
625 Dependencies::print_dependency(type(), args, witness);
626 if (verbose) {
627 if (_code != NULL) {
628 tty->print(" code: ");
629 _code->print_value_on(tty);
630 tty->cr();
631 }
632 }
633 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
634 }
635
636
637 /// Dependency stream support (decodes dependencies from an nmethod):
638
639 #ifdef ASSERT
640 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
641 assert(must_be_in_vm(), "raw oops here");
642 _byte_limit = byte_limit;
643 _type = (DepType)(end_marker-1); // defeat "already at end" assert
644 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
645 }
646 #endif //ASSERT
647
648 bool Dependencies::DepStream::next() {
649 assert(_type != end_marker, "already at end");
650 if (_bytes.position() == 0 && _code != NULL
651 && _code->dependencies_size() == 0) {
652 // Method has no dependencies at all.
653 return false;
654 }
655 int code_byte = (_bytes.read_byte() & 0xFF);
656 if (code_byte == end_marker) {
657 DEBUG_ONLY(_type = end_marker);
658 return false;
659 } else {
660 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
661 code_byte -= ctxk_bit;
662 DepType dept = (DepType)code_byte;
663 _type = dept;
664 Dependencies::check_valid_dependency_type(dept);
665 int stride = _dep_args[dept];
666 assert(stride == dep_args(dept), "sanity");
667 int skipj = -1;
668 if (ctxk_bit != 0) {
669 skipj = 0; // currently the only context argument is at zero
670 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
671 }
672 for (int j = 0; j < stride; j++) {
673 _xi[j] = (j == skipj)? 0: _bytes.read_int();
674 }
675 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
676 return true;
677 }
678 }
679
680 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
681 Metadata* o = NULL;
682 if (_code != NULL) {
683 o = _code->metadata_at(i);
684 } else {
685 o = _deps->oop_recorder()->metadata_at(i);
686 }
687 return o;
688 }
689
690 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
691 return (_code != NULL)
692 ? _code->oop_at(i)
693 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
694 }
695
696 Metadata* Dependencies::DepStream::argument(int i) {
697 Metadata* result = recorded_metadata_at(argument_index(i));
698
699 if (result == NULL) { // Explicit context argument can be compressed
700 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
701 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
702 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
703 }
704 }
705
706 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
707 return result;
708 }
709
710 /**
711 * Returns a unique identifier for each dependency argument.
712 */
713 uintptr_t Dependencies::DepStream::get_identifier(int i) {
714 if (is_oop_argument(i)) {
715 return (uintptr_t)(oopDesc*)argument_oop(i);
716 } else {
717 return (uintptr_t)argument(i);
718 }
719 }
720
721 oop Dependencies::DepStream::argument_oop(int i) {
722 oop result = recorded_oop_at(argument_index(i));
723 assert(result == NULL || result->is_oop(), "must be");
724 return result;
725 }
726
727 Klass* Dependencies::DepStream::context_type() {
728 assert(must_be_in_vm(), "raw oops here");
729
730 // Most dependencies have an explicit context type argument.
731 {
732 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
733 if (ctxkj >= 0) {
734 Metadata* k = argument(ctxkj);
735 assert(k != NULL && k->is_klass(), "type check");
736 return (Klass*)k;
737 }
738 }
739
740 // Some dependencies are using the klass of the first object
741 // argument as implicit context type.
742 {
743 int ctxkj = dep_implicit_context_arg(type());
744 if (ctxkj >= 0) {
745 Klass* k = argument_oop(ctxkj)->klass();
746 assert(k != NULL && k->is_klass(), "type check");
747 return (Klass*) k;
748 }
749 }
750
751 // And some dependencies don't have a context type at all,
752 // e.g. evol_method.
753 return NULL;
754 }
755
756 // ----------------- DependencySignature --------------------------------------
757 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
758 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
759 return false;
760 }
761
762 for (int i = 0; i < s1.args_count(); i++) {
763 if (s1.arg(i) != s2.arg(i)) {
764 return false;
765 }
766 }
767 return true;
768 }
769
770 /// Checking dependencies:
771
772 // This hierarchy walker inspects subtypes of a given type,
773 // trying to find a "bad" class which breaks a dependency.
774 // Such a class is called a "witness" to the broken dependency.
775 // While searching around, we ignore "participants", which
776 // are already known to the dependency.
777 class ClassHierarchyWalker {
778 public:
779 enum { PARTICIPANT_LIMIT = 3 };
780
781 private:
782 // optional method descriptor to check for:
783 Symbol* _name;
784 Symbol* _signature;
785
786 // special classes which are not allowed to be witnesses:
787 Klass* _participants[PARTICIPANT_LIMIT+1];
788 int _num_participants;
789
790 // cache of method lookups
791 Method* _found_methods[PARTICIPANT_LIMIT+1];
792
793 // if non-zero, tells how many witnesses to convert to participants
794 int _record_witnesses;
795
796 void initialize(Klass* participant) {
797 _record_witnesses = 0;
798 _participants[0] = participant;
799 _found_methods[0] = NULL;
800 _num_participants = 0;
801 if (participant != NULL) {
802 // Terminating NULL.
803 _participants[1] = NULL;
804 _found_methods[1] = NULL;
805 _num_participants = 1;
806 }
807 }
808
809 void initialize_from_method(Method* m) {
810 assert(m != NULL && m->is_method(), "sanity");
811 _name = m->name();
812 _signature = m->signature();
813 }
814
815 public:
816 // The walker is initialized to recognize certain methods and/or types
817 // as friendly participants.
818 ClassHierarchyWalker(Klass* participant, Method* m) {
819 initialize_from_method(m);
820 initialize(participant);
821 }
822 ClassHierarchyWalker(Method* m) {
823 initialize_from_method(m);
824 initialize(NULL);
825 }
826 ClassHierarchyWalker(Klass* participant = NULL) {
827 _name = NULL;
828 _signature = NULL;
829 initialize(participant);
830 }
831
832 // This is common code for two searches: One for concrete subtypes,
833 // the other for concrete method implementations and overrides.
834 bool doing_subtype_search() {
835 return _name == NULL;
836 }
837
838 int num_participants() { return _num_participants; }
839 Klass* participant(int n) {
840 assert((uint)n <= (uint)_num_participants, "oob");
841 return _participants[n];
842 }
843
844 // Note: If n==num_participants, returns NULL.
845 Method* found_method(int n) {
846 assert((uint)n <= (uint)_num_participants, "oob");
847 Method* fm = _found_methods[n];
848 assert(n == _num_participants || fm != NULL, "proper usage");
849 if (fm != NULL && fm->method_holder() != _participants[n]) {
850 // Default methods from interfaces can be added to classes. In
851 // that case the holder of the method is not the class but the
852 // interface where it's defined.
853 assert(fm->is_default_method(), "sanity");
854 return NULL;
855 }
856 return fm;
857 }
858
859 #ifdef ASSERT
860 // Assert that m is inherited into ctxk, without intervening overrides.
861 // (May return true even if this is not true, in corner cases where we punt.)
862 bool check_method_context(Klass* ctxk, Method* m) {
863 if (m->method_holder() == ctxk)
864 return true; // Quick win.
865 if (m->is_private())
866 return false; // Quick lose. Should not happen.
867 if (!(m->is_public() || m->is_protected()))
868 // The override story is complex when packages get involved.
869 return true; // Must punt the assertion to true.
870 Klass* k = ctxk;
871 Method* lm = k->lookup_method(m->name(), m->signature());
872 if (lm == NULL && k->oop_is_instance()) {
873 // It might be an interface method
874 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
875 m->signature());
876 }
877 if (lm == m)
878 // Method m is inherited into ctxk.
879 return true;
880 if (lm != NULL) {
881 if (!(lm->is_public() || lm->is_protected())) {
882 // Method is [package-]private, so the override story is complex.
883 return true; // Must punt the assertion to true.
884 }
885 if (lm->is_static()) {
886 // Static methods don't override non-static so punt
887 return true;
888 }
889 if ( !Dependencies::is_concrete_method(lm, k)
890 && !Dependencies::is_concrete_method(m, ctxk)
891 && lm->method_holder()->is_subtype_of(m->method_holder()))
892 // Method m is overridden by lm, but both are non-concrete.
893 return true;
894 }
895 ResourceMark rm;
896 tty->print_cr("Dependency method not found in the associated context:");
897 tty->print_cr(" context = %s", ctxk->external_name());
898 tty->print( " method = "); m->print_short_name(tty); tty->cr();
899 if (lm != NULL) {
900 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
901 }
902 return false;
903 }
904 #endif
905
906 void add_participant(Klass* participant) {
907 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
908 int np = _num_participants++;
909 _participants[np] = participant;
910 _participants[np+1] = NULL;
911 _found_methods[np+1] = NULL;
912 }
913
914 void record_witnesses(int add) {
915 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
916 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
917 _record_witnesses = add;
918 }
919
920 bool is_witness(Klass* k) {
921 if (doing_subtype_search()) {
922 return Dependencies::is_concrete_klass(k);
923 } else if (!k->oop_is_instance()) {
924 return false; // no methods to find in an array type
925 } else {
926 // Search class hierarchy first.
927 Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature);
928 if (!Dependencies::is_concrete_method(m, k)) {
929 // Check interface defaults also, if any exist.
930 Array<Method*>* default_methods = InstanceKlass::cast(k)->default_methods();
931 if (default_methods == NULL)
932 return false;
933 m = InstanceKlass::cast(k)->find_method(default_methods, _name, _signature);
934 if (!Dependencies::is_concrete_method(m, NULL))
935 return false;
936 }
937 _found_methods[_num_participants] = m;
938 // Note: If add_participant(k) is called,
939 // the method m will already be memoized for it.
940 return true;
941 }
942 }
943
944 bool is_participant(Klass* k) {
945 if (k == _participants[0]) {
946 return true;
947 } else if (_num_participants <= 1) {
948 return false;
949 } else {
950 return in_list(k, &_participants[1]);
951 }
952 }
953 bool ignore_witness(Klass* witness) {
954 if (_record_witnesses == 0) {
955 return false;
956 } else {
957 --_record_witnesses;
958 add_participant(witness);
959 return true;
960 }
961 }
962 static bool in_list(Klass* x, Klass** list) {
963 for (int i = 0; ; i++) {
964 Klass* y = list[i];
965 if (y == NULL) break;
966 if (y == x) return true;
967 }
968 return false; // not in list
969 }
970
971 private:
972 // the actual search method:
973 Klass* find_witness_anywhere(Klass* context_type,
974 bool participants_hide_witnesses,
975 bool top_level_call = true);
976 // the spot-checking version:
977 Klass* find_witness_in(KlassDepChange& changes,
978 Klass* context_type,
979 bool participants_hide_witnesses);
980 public:
981 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
982 assert(doing_subtype_search(), "must set up a subtype search");
983 // When looking for unexpected concrete types,
984 // do not look beneath expected ones.
985 const bool participants_hide_witnesses = true;
986 // CX > CC > C' is OK, even if C' is new.
987 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
988 if (changes != NULL) {
989 return find_witness_in(*changes, context_type, participants_hide_witnesses);
990 } else {
991 return find_witness_anywhere(context_type, participants_hide_witnesses);
992 }
993 }
994 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
995 assert(!doing_subtype_search(), "must set up a method definer search");
996 // When looking for unexpected concrete methods,
997 // look beneath expected ones, to see if there are overrides.
998 const bool participants_hide_witnesses = true;
999 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
1000 if (changes != NULL) {
1001 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
1002 } else {
1003 return find_witness_anywhere(context_type, !participants_hide_witnesses);
1004 }
1005 }
1006 };
1007
1008 #ifndef PRODUCT
1009 static int deps_find_witness_calls = 0;
1010 static int deps_find_witness_steps = 0;
1011 static int deps_find_witness_recursions = 0;
1012 static int deps_find_witness_singles = 0;
1013 static int deps_find_witness_print = 0; // set to -1 to force a final print
1014 static bool count_find_witness_calls() {
1015 if (TraceDependencies || LogCompilation) {
1016 int pcount = deps_find_witness_print + 1;
1017 bool final_stats = (pcount == 0);
1018 bool initial_call = (pcount == 1);
1019 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
1020 if (pcount < 0) pcount = 1; // crude overflow protection
1021 deps_find_witness_print = pcount;
1022 if (VerifyDependencies && initial_call) {
1023 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
1024 }
1025 if (occasional_print || final_stats) {
1026 // Every now and then dump a little info about dependency searching.
1027 if (xtty != NULL) {
1028 ttyLocker ttyl;
1029 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
1030 deps_find_witness_calls,
1031 deps_find_witness_steps,
1032 deps_find_witness_recursions,
1033 deps_find_witness_singles);
1034 }
1035 if (final_stats || (TraceDependencies && WizardMode)) {
1036 ttyLocker ttyl;
1037 tty->print_cr("Dependency check (find_witness) "
1038 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
1039 deps_find_witness_calls,
1040 deps_find_witness_steps,
1041 (double)deps_find_witness_steps / deps_find_witness_calls,
1042 deps_find_witness_recursions,
1043 deps_find_witness_singles);
1044 }
1045 }
1046 return true;
1047 }
1048 return false;
1049 }
1050 #else
1051 #define count_find_witness_calls() (0)
1052 #endif //PRODUCT
1053
1054
1055 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1056 Klass* context_type,
1057 bool participants_hide_witnesses) {
1058 assert(changes.involves_context(context_type), "irrelevant dependency");
1059 Klass* new_type = changes.new_type();
1060
1061 (void)count_find_witness_calls();
1062 NOT_PRODUCT(deps_find_witness_singles++);
1063
1064 // Current thread must be in VM (not native mode, as in CI):
1065 assert(must_be_in_vm(), "raw oops here");
1066 // Must not move the class hierarchy during this check:
1067 assert_locked_or_safepoint(Compile_lock);
1068
1069 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1070 if (nof_impls > 1) {
1071 // Avoid this case: *I.m > { A.m, C }; B.m > C
1072 // %%% Until this is fixed more systematically, bail out.
1073 // See corresponding comment in find_witness_anywhere.
1074 return context_type;
1075 }
1076
1077 assert(!is_participant(new_type), "only old classes are participants");
1078 if (participants_hide_witnesses) {
1079 // If the new type is a subtype of a participant, we are done.
1080 for (int i = 0; i < num_participants(); i++) {
1081 Klass* part = participant(i);
1082 if (part == NULL) continue;
1083 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1084 "correct marking of participants, b/c new_type is unique");
1085 if (changes.involves_context(part)) {
1086 // new guy is protected from this check by previous participant
1087 return NULL;
1088 }
1089 }
1090 }
1091
1092 if (is_witness(new_type) &&
1093 !ignore_witness(new_type)) {
1094 return new_type;
1095 }
1096
1097 return NULL;
1098 }
1099
1100
1101 // Walk hierarchy under a context type, looking for unexpected types.
1102 // Do not report participant types, and recursively walk beneath
1103 // them only if participants_hide_witnesses is false.
1104 // If top_level_call is false, skip testing the context type,
1105 // because the caller has already considered it.
1106 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1107 bool participants_hide_witnesses,
1108 bool top_level_call) {
1109 // Current thread must be in VM (not native mode, as in CI):
1110 assert(must_be_in_vm(), "raw oops here");
1111 // Must not move the class hierarchy during this check:
1112 assert_locked_or_safepoint(Compile_lock);
1113
1114 bool do_counts = count_find_witness_calls();
1115
1116 // Check the root of the sub-hierarchy first.
1117 if (top_level_call) {
1118 if (do_counts) {
1119 NOT_PRODUCT(deps_find_witness_calls++);
1120 NOT_PRODUCT(deps_find_witness_steps++);
1121 }
1122 if (is_participant(context_type)) {
1123 if (participants_hide_witnesses) return NULL;
1124 // else fall through to search loop...
1125 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1126 // The context is an abstract class or interface, to start with.
1127 return context_type;
1128 }
1129 }
1130
1131 // Now we must check each implementor and each subclass.
1132 // Use a short worklist to avoid blowing the stack.
1133 // Each worklist entry is a *chain* of subklass siblings to process.
1134 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1135 Klass* chains[CHAINMAX];
1136 int chaini = 0; // index into worklist
1137 Klass* chain; // scratch variable
1138 #define ADD_SUBCLASS_CHAIN(k) { \
1139 assert(chaini < CHAINMAX, "oob"); \
1140 chain = k->subklass(); \
1141 if (chain != NULL) chains[chaini++] = chain; }
1142
1143 // Look for non-abstract subclasses.
1144 // (Note: Interfaces do not have subclasses.)
1145 ADD_SUBCLASS_CHAIN(context_type);
1146
1147 // If it is an interface, search its direct implementors.
1148 // (Their subclasses are additional indirect implementors.
1149 // See InstanceKlass::add_implementor.)
1150 // (Note: nof_implementors is always zero for non-interfaces.)
1151 if (top_level_call) {
1152 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1153 if (nof_impls > 1) {
1154 // Avoid this case: *I.m > { A.m, C }; B.m > C
1155 // Here, I.m has 2 concrete implementations, but m appears unique
1156 // as A.m, because the search misses B.m when checking C.
1157 // The inherited method B.m was getting missed by the walker
1158 // when interface 'I' was the starting point.
1159 // %%% Until this is fixed more systematically, bail out.
1160 // (Old CHA had the same limitation.)
1161 return context_type;
1162 }
1163 if (nof_impls > 0) {
1164 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1165 assert(impl != NULL, "just checking");
1166 // If impl is the same as the context_type, then more than one
1167 // implementor has seen. No exact info in this case.
1168 if (impl == context_type) {
1169 return context_type; // report an inexact witness to this sad affair
1170 }
1171 if (do_counts)
1172 { NOT_PRODUCT(deps_find_witness_steps++); }
1173 if (is_participant(impl)) {
1174 if (!participants_hide_witnesses) {
1175 ADD_SUBCLASS_CHAIN(impl);
1176 }
1177 } else if (is_witness(impl) && !ignore_witness(impl)) {
1178 return impl;
1179 } else {
1180 ADD_SUBCLASS_CHAIN(impl);
1181 }
1182 }
1183 }
1184
1185 // Recursively process each non-trivial sibling chain.
1186 while (chaini > 0) {
1187 Klass* chain = chains[--chaini];
1188 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1189 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1190 if (is_participant(sub)) {
1191 if (participants_hide_witnesses) continue;
1192 // else fall through to process this guy's subclasses
1193 } else if (is_witness(sub) && !ignore_witness(sub)) {
1194 return sub;
1195 }
1196 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1197 // Fast path. (Partially disabled if VerifyDependencies.)
1198 ADD_SUBCLASS_CHAIN(sub);
1199 } else {
1200 // Worklist overflow. Do a recursive call. Should be rare.
1201 // The recursive call will have its own worklist, of course.
1202 // (Note that sub has already been tested, so that there is
1203 // no need for the recursive call to re-test. That's handy,
1204 // since the recursive call sees sub as the context_type.)
1205 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1206 Klass* witness = find_witness_anywhere(sub,
1207 participants_hide_witnesses,
1208 /*top_level_call=*/ false);
1209 if (witness != NULL) return witness;
1210 }
1211 }
1212 }
1213
1214 // No witness found. The dependency remains unbroken.
1215 return NULL;
1216 #undef ADD_SUBCLASS_CHAIN
1217 }
1218
1219
1220 bool Dependencies::is_concrete_klass(Klass* k) {
1221 if (k->is_abstract()) return false;
1222 // %%% We could treat classes which are concrete but
1223 // have not yet been instantiated as virtually abstract.
1224 // This would require a deoptimization barrier on first instantiation.
1225 //if (k->is_not_instantiated()) return false;
1226 return true;
1227 }
1228
1229 bool Dependencies::is_concrete_method(Method* m, Klass * k) {
1230 // NULL is not a concrete method,
1231 // statics are irrelevant to virtual call sites,
1232 // abstract methods are not concrete,
1233 // overpass (error) methods are not concrete if k is abstract
1234 //
1235 // note "true" is conservative answer --
1236 // overpass clause is false if k == NULL, implies return true if
1237 // answer depends on overpass clause.
1238 return ! ( m == NULL || m -> is_static() || m -> is_abstract() ||
1239 m->is_overpass() && k != NULL && k -> is_abstract() );
1240 }
1241
1242
1243 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1244 if (k->is_interface()) return NULL;
1245 if (k->has_finalizer()) return k;
1246 k = k->subklass();
1247 while (k != NULL) {
1248 Klass* result = find_finalizable_subclass(k);
1249 if (result != NULL) return result;
1250 k = k->next_sibling();
1251 }
1252 return NULL;
1253 }
1254
1255
1256 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1257 if (k->is_abstract()) return false;
1258 // We could also return false if k does not yet appear to be
1259 // instantiated, if the VM version supports this distinction also.
1260 //if (k->is_not_instantiated()) return false;
1261 return true;
1262 }
1263
1264 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1265 return k->has_finalizable_subclass();
1266 }
1267
1268
1269 // Any use of the contents (bytecodes) of a method must be
1270 // marked by an "evol_method" dependency, if those contents
1271 // can change. (Note: A method is always dependent on itself.)
1272 Klass* Dependencies::check_evol_method(Method* m) {
1273 assert(must_be_in_vm(), "raw oops here");
1274 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1275 // Or is there a now a breakpoint?
1276 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1277 if (m->is_old()
1278 || m->number_of_breakpoints() > 0) {
1279 return m->method_holder();
1280 } else {
1281 return NULL;
1282 }
1283 }
1284
1285 // This is a strong assertion: It is that the given type
1286 // has no subtypes whatever. It is most useful for
1287 // optimizing checks on reflected types or on array types.
1288 // (Checks on types which are derived from real instances
1289 // can be optimized more strongly than this, because we
1290 // know that the checked type comes from a concrete type,
1291 // and therefore we can disregard abstract types.)
1292 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1293 assert(must_be_in_vm(), "raw oops here");
1294 assert_locked_or_safepoint(Compile_lock);
1295 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1296 Klass* sub = ctx->subklass();
1297 if (sub != NULL) {
1298 return sub;
1299 } else if (ctx->nof_implementors() != 0) {
1300 // if it is an interface, it must be unimplemented
1301 // (if it is not an interface, nof_implementors is always zero)
1302 Klass* impl = ctx->implementor();
1303 assert(impl != NULL, "must be set");
1304 return impl;
1305 } else {
1306 return NULL;
1307 }
1308 }
1309
1310 // Test the assertion that conck is the only concrete subtype* of ctxk.
1311 // The type conck itself is allowed to have have further concrete subtypes.
1312 // This allows the compiler to narrow occurrences of ctxk by conck,
1313 // when dealing with the types of actual instances.
1314 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1315 Klass* conck,
1316 KlassDepChange* changes) {
1317 ClassHierarchyWalker wf(conck);
1318 return wf.find_witness_subtype(ctxk, changes);
1319 }
1320
1321 // If a non-concrete class has no concrete subtypes, it is not (yet)
1322 // instantiatable. This can allow the compiler to make some paths go
1323 // dead, if they are gated by a test of the type.
1324 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1325 KlassDepChange* changes) {
1326 // Find any concrete subtype, with no participants:
1327 ClassHierarchyWalker wf;
1328 return wf.find_witness_subtype(ctxk, changes);
1329 }
1330
1331
1332 // If a concrete class has no concrete subtypes, it can always be
1333 // exactly typed. This allows the use of a cheaper type test.
1334 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1335 KlassDepChange* changes) {
1336 // Find any concrete subtype, with only the ctxk as participant:
1337 ClassHierarchyWalker wf(ctxk);
1338 return wf.find_witness_subtype(ctxk, changes);
1339 }
1340
1341
1342 // Find the unique concrete proper subtype of ctxk, or NULL if there
1343 // is more than one concrete proper subtype. If there are no concrete
1344 // proper subtypes, return ctxk itself, whether it is concrete or not.
1345 // The returned subtype is allowed to have have further concrete subtypes.
1346 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1347 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1348 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1349 wf.record_witnesses(1); // Record one other witness when walking.
1350 Klass* wit = wf.find_witness_subtype(ctxk);
1351 if (wit != NULL) return NULL; // Too many witnesses.
1352 Klass* conck = wf.participant(0);
1353 if (conck == NULL) {
1354 #ifndef PRODUCT
1355 // Make sure the dependency mechanism will pass this discovery:
1356 if (VerifyDependencies) {
1357 // Turn off dependency tracing while actually testing deps.
1358 FlagSetting fs(TraceDependencies, false);
1359 if (!Dependencies::is_concrete_klass(ctxk)) {
1360 guarantee(NULL ==
1361 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1362 "verify dep.");
1363 } else {
1364 guarantee(NULL ==
1365 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1366 "verify dep.");
1367 }
1368 }
1369 #endif //PRODUCT
1370 return ctxk; // Return ctxk as a flag for "no subtypes".
1371 } else {
1372 #ifndef PRODUCT
1373 // Make sure the dependency mechanism will pass this discovery:
1374 if (VerifyDependencies) {
1375 // Turn off dependency tracing while actually testing deps.
1376 FlagSetting fs(TraceDependencies, false);
1377 if (!Dependencies::is_concrete_klass(ctxk)) {
1378 guarantee(NULL == (void *)
1379 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1380 "verify dep.");
1381 }
1382 }
1383 #endif //PRODUCT
1384 return conck;
1385 }
1386 }
1387
1388 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1389 // except possibly for further subtypes of k[12] themselves.
1390 // The context type must be abstract. The types k1 and k2 are themselves
1391 // allowed to have further concrete subtypes.
1392 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1393 Klass* ctxk,
1394 Klass* k1,
1395 Klass* k2,
1396 KlassDepChange* changes) {
1397 ClassHierarchyWalker wf;
1398 wf.add_participant(k1);
1399 wf.add_participant(k2);
1400 return wf.find_witness_subtype(ctxk, changes);
1401 }
1402
1403 // Search ctxk for concrete implementations. If there are klen or fewer,
1404 // pack them into the given array and return the number.
1405 // Otherwise, return -1, meaning the given array would overflow.
1406 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1407 // In this search, if ctxk is concrete, it will be reported alone.
1408 // For any type CC reported, no proper subtypes of CC will be reported.
1409 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1410 int klen,
1411 Klass* karray[]) {
1412 ClassHierarchyWalker wf;
1413 wf.record_witnesses(klen);
1414 Klass* wit = wf.find_witness_subtype(ctxk);
1415 if (wit != NULL) return -1; // Too many witnesses.
1416 int num = wf.num_participants();
1417 assert(num <= klen, "oob");
1418 // Pack the result array with the good news.
1419 for (int i = 0; i < num; i++)
1420 karray[i] = wf.participant(i);
1421 #ifndef PRODUCT
1422 // Make sure the dependency mechanism will pass this discovery:
1423 if (VerifyDependencies) {
1424 // Turn off dependency tracing while actually testing deps.
1425 FlagSetting fs(TraceDependencies, false);
1426 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1427 case -1: // ctxk was itself concrete
1428 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1429 break;
1430 case 0:
1431 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1432 "verify dep.");
1433 break;
1434 case 1:
1435 guarantee(NULL == (void *)
1436 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1437 "verify dep.");
1438 break;
1439 case 2:
1440 guarantee(NULL == (void *)
1441 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1442 karray[0],
1443 karray[1]),
1444 "verify dep.");
1445 break;
1446 default:
1447 ShouldNotReachHere(); // klen > 2 yet supported
1448 }
1449 }
1450 #endif //PRODUCT
1451 return num;
1452 }
1453
1454 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1455 // Otherwise, return a class that contains an interfering method.
1456 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1457 KlassDepChange* changes) {
1458 // Here is a missing optimization: If uniqm->is_final(),
1459 // we don't really need to search beneath it for overrides.
1460 // This is probably not important, since we don't use dependencies
1461 // to track final methods. (They can't be "definalized".)
1462 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1463 return wf.find_witness_definer(ctxk, changes);
1464 }
1465
1466 // Find the set of all non-abstract methods under ctxk that match m.
1467 // (The method m must be defined or inherited in ctxk.)
1468 // Include m itself in the set, unless it is abstract.
1469 // If this set has exactly one element, return that element.
1470 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1471 // Return NULL if m is marked old; must have been a redefined method.
1472 if (m->is_old()) {
1473 return NULL;
1474 }
1475 ClassHierarchyWalker wf(m);
1476 assert(wf.check_method_context(ctxk, m), "proper context");
1477 wf.record_witnesses(1);
1478 Klass* wit = wf.find_witness_definer(ctxk);
1479 if (wit != NULL) return NULL; // Too many witnesses.
1480 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1481 if (Dependencies::is_concrete_method(m, ctxk)) {
1482 if (fm == NULL) {
1483 // It turns out that m was always the only implementation.
1484 fm = m;
1485 } else if (fm != m) {
1486 // Two conflicting implementations after all.
1487 // (This can happen if m is inherited into ctxk and fm overrides it.)
1488 return NULL;
1489 }
1490 }
1491 #ifndef PRODUCT
1492 // Make sure the dependency mechanism will pass this discovery:
1493 if (VerifyDependencies && fm != NULL) {
1494 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1495 "verify dep.");
1496 }
1497 #endif //PRODUCT
1498 return fm;
1499 }
1500
1501 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1502 Method* m1,
1503 Method* m2,
1504 KlassDepChange* changes) {
1505 ClassHierarchyWalker wf(m1);
1506 wf.add_participant(m1->method_holder());
1507 wf.add_participant(m2->method_holder());
1508 return wf.find_witness_definer(ctxk, changes);
1509 }
1510
1511 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1512 Klass* search_at = ctxk;
1513 if (changes != NULL)
1514 search_at = changes->new_type(); // just look at the new bit
1515 return find_finalizable_subclass(search_at);
1516 }
1517
1518 Klass* Dependencies::check_call_site_target_value(Klass* recorded_ctxk, oop call_site, oop method_handle, CallSiteDepChange* changes) {
1519 assert(call_site->is_a(SystemDictionary::CallSite_klass()), "sanity");
1520 assert(!oopDesc::is_null(method_handle), "sanity");
1521
1522 Klass* call_site_ctxk = MethodHandles::get_call_site_context(call_site);
1523 assert(!Klass::is_null(call_site_ctxk), "call site context should be initialized already");
1524 if (recorded_ctxk != call_site_ctxk) {
1525 // Stale context
1526 return recorded_ctxk;
1527 }
1528 if (changes == NULL) {
1529 // Validate all CallSites
1530 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1531 return call_site->klass(); // assertion failed
1532 } else {
1533 // Validate the given CallSite
1534 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1535 assert(method_handle != changes->method_handle(), "must be");
1536 return call_site->klass(); // assertion failed
1537 }
1538 }
1539 return NULL; // assertion still valid
1540 }
1541
1542 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1543 if (witness != NULL) {
1544 if (TraceDependencies) {
1545 print_dependency(witness, /*verbose=*/ true);
1546 }
1547 // The following is a no-op unless logging is enabled:
1548 log_dependency(witness);
1549 }
1550 }
1551
1552
1553 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1554 assert_locked_or_safepoint(Compile_lock);
1555 Dependencies::check_valid_dependency_type(type());
1556
1557 Klass* witness = NULL;
1558 switch (type()) {
1559 case evol_method:
1560 witness = check_evol_method(method_argument(0));
1561 break;
1562 case leaf_type:
1563 witness = check_leaf_type(context_type());
1564 break;
1565 case abstract_with_unique_concrete_subtype:
1566 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1567 break;
1568 case abstract_with_no_concrete_subtype:
1569 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1570 break;
1571 case concrete_with_no_concrete_subtype:
1572 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1573 break;
1574 case unique_concrete_method:
1575 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1576 break;
1577 case abstract_with_exclusive_concrete_subtypes_2:
1578 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1579 break;
1580 case exclusive_concrete_methods_2:
1581 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1582 break;
1583 case no_finalizable_subclasses:
1584 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1585 break;
1586 default:
1587 witness = NULL;
1588 break;
1589 }
1590 trace_and_log_witness(witness);
1591 return witness;
1592 }
1593
1594
1595 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1596 assert_locked_or_safepoint(Compile_lock);
1597 Dependencies::check_valid_dependency_type(type());
1598
1599 Klass* witness = NULL;
1600 switch (type()) {
1601 case call_site_target_value:
1602 witness = check_call_site_target_value(context_type(), argument_oop(1), argument_oop(2), changes);
1603 break;
1604 default:
1605 witness = NULL;
1606 break;
1607 }
1608 trace_and_log_witness(witness);
1609 return witness;
1610 }
1611
1612
1613 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1614 // Handle klass dependency
1615 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1616 return check_klass_dependency(changes.as_klass_change());
1617
1618 // Handle CallSite dependency
1619 if (changes.is_call_site_change())
1620 return check_call_site_dependency(changes.as_call_site_change());
1621
1622 // irrelevant dependency; skip it
1623 return NULL;
1624 }
1625
1626
1627 void DepChange::print() {
1628 int nsup = 0, nint = 0;
1629 for (ContextStream str(*this); str.next(); ) {
1630 Klass* k = str.klass();
1631 switch (str.change_type()) {
1632 case Change_new_type:
1633 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1634 break;
1635 case Change_new_sub:
1636 if (!WizardMode) {
1637 ++nsup;
1638 } else {
1639 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1640 }
1641 break;
1642 case Change_new_impl:
1643 if (!WizardMode) {
1644 ++nint;
1645 } else {
1646 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1647 }
1648 break;
1649 }
1650 }
1651 if (nsup + nint != 0) {
1652 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1653 }
1654 }
1655
1656 void DepChange::ContextStream::start() {
1657 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1658 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1659 _klass = new_type;
1660 _ti_base = NULL;
1661 _ti_index = 0;
1662 _ti_limit = 0;
1663 }
1664
1665 bool DepChange::ContextStream::next() {
1666 switch (_change_type) {
1667 case Start_Klass: // initial state; _klass is the new type
1668 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1669 _ti_index = 0;
1670 _change_type = Change_new_type;
1671 return true;
1672 case Change_new_type:
1673 // fall through:
1674 _change_type = Change_new_sub;
1675 case Change_new_sub:
1676 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1677 {
1678 _klass = InstanceKlass::cast(_klass)->super();
1679 if (_klass != NULL) {
1680 return true;
1681 }
1682 }
1683 // else set up _ti_limit and fall through:
1684 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1685 _change_type = Change_new_impl;
1686 case Change_new_impl:
1687 if (_ti_index < _ti_limit) {
1688 _klass = _ti_base->at(_ti_index++);
1689 return true;
1690 }
1691 // fall through:
1692 _change_type = NO_CHANGE; // iterator is exhausted
1693 case NO_CHANGE:
1694 break;
1695 default:
1696 ShouldNotReachHere();
1697 }
1698 return false;
1699 }
1700
1701 void KlassDepChange::initialize() {
1702 // entire transaction must be under this lock:
1703 assert_lock_strong(Compile_lock);
1704
1705 // Mark all dependee and all its superclasses
1706 // Mark transitive interfaces
1707 for (ContextStream str(*this); str.next(); ) {
1708 Klass* d = str.klass();
1709 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1710 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1711 }
1712 }
1713
1714 KlassDepChange::~KlassDepChange() {
1715 // Unmark all dependee and all its superclasses
1716 // Unmark transitive interfaces
1717 for (ContextStream str(*this); str.next(); ) {
1718 Klass* d = str.klass();
1719 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1720 }
1721 }
1722
1723 bool KlassDepChange::involves_context(Klass* k) {
1724 if (k == NULL || !k->oop_is_instance()) {
1725 return false;
1726 }
1727 InstanceKlass* ik = InstanceKlass::cast(k);
1728 bool is_contained = ik->is_marked_dependent();
1729 assert(is_contained == new_type()->is_subtype_of(k),
1730 "correct marking of potential context types");
1731 return is_contained;
1732 }
1733
1734 #ifndef PRODUCT
1735 void Dependencies::print_statistics() {
1736 if (deps_find_witness_print != 0) {
1737 // Call one final time, to flush out the data.
1738 deps_find_witness_print = -1;
1739 count_find_witness_calls();
1740 }
1741 }
1742 #endif