Thu, 07 Aug 2014 18:09:12 -0700
8040920: Uninitialised memory in hotspot/src/share/vm/code/dependencies.cpp
Summary: Fixed parfait initialization issue.
Reviewed-by: kvn, twisti
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 */
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"
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
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;
61 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
62 }
64 void Dependencies::assert_evol_method(ciMethod* m) {
65 assert_common_1(evol_method, m);
66 }
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 }
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 }
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 }
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 }
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 }
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 }
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 }
113 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
114 check_ctxk(ctxk);
115 assert_common_1(no_finalizable_subclasses, ctxk);
116 }
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 }
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 }
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];
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 }
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];
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 }
190 // append the assertion in the correct bucket:
191 deps->append(x0);
192 deps->append(x1);
193 }
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];
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; }
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 }
234 /// Support for encoding dependencies into an nmethod:
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 }
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); }
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 }
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 }
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 }
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 }
309 void Dependencies::encode_content_bytes() {
310 sort_all_deps();
312 // cast is safe, no deps can overflow INT_MAX
313 CompressedWriteStream bytes((int)estimate_size_in_bytes());
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 }
349 // write a sentinel byte to mark the end
350 bytes.write_byte(end_marker);
352 // round it out to a word boundary
353 while (bytes.position() % sizeof(HeapWord) != 0) {
354 bytes.write_byte(end_marker);
355 }
357 // check whether the dept byte encoding really works
358 assert((jbyte)default_context_type_bit != 0, "byte overflow");
360 _content_bytes = bytes.buffer();
361 _size_in_bytes = bytes.position();
362 }
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 };
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 };
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 }
398 int Dependencies::dep_args(Dependencies::DepType dept) {
399 if (!dept_in_mask(dept, all_types)) return -1;
400 return _dep_args[dept];
401 }
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 }
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 }
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 }
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 }
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 }
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
575 ShouldNotReachHere(); // Provide impl for this type.
576 tty->cr();
577 }
578 if (witness != NULL) {
579 bool put_star = !Dependencies::is_concrete_klass(witness);
580 tty->print_cr(" witness = %s%s",
581 (put_star? "*": ""),
582 witness->external_name());
583 }
584 }
586 void Dependencies::DepStream::log_dependency(Klass* witness) {
587 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
588 ResourceMark rm;
589 const int nargs = argument_count();
590 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
591 for (int j = 0; j < nargs; j++) {
592 if (type() == call_site_target_value) {
593 args->push(argument_oop(j));
594 } else {
595 args->push(argument(j));
596 }
597 }
598 int argslen = args->length();
599 if (_deps != NULL && _deps->log() != NULL) {
600 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
601 } else {
602 Dependencies::write_dependency_to(xtty, type(), args, witness);
603 }
604 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
605 }
607 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
608 ResourceMark rm;
609 int nargs = argument_count();
610 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
611 for (int j = 0; j < nargs; j++) {
612 args->push(argument(j));
613 }
614 int argslen = args->length();
615 Dependencies::print_dependency(type(), args, witness);
616 if (verbose) {
617 if (_code != NULL) {
618 tty->print(" code: ");
619 _code->print_value_on(tty);
620 tty->cr();
621 }
622 }
623 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
624 }
627 /// Dependency stream support (decodes dependencies from an nmethod):
629 #ifdef ASSERT
630 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
631 assert(must_be_in_vm(), "raw oops here");
632 _byte_limit = byte_limit;
633 _type = (DepType)(end_marker-1); // defeat "already at end" assert
634 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
635 }
636 #endif //ASSERT
638 bool Dependencies::DepStream::next() {
639 assert(_type != end_marker, "already at end");
640 if (_bytes.position() == 0 && _code != NULL
641 && _code->dependencies_size() == 0) {
642 // Method has no dependencies at all.
643 return false;
644 }
645 int code_byte = (_bytes.read_byte() & 0xFF);
646 if (code_byte == end_marker) {
647 DEBUG_ONLY(_type = end_marker);
648 return false;
649 } else {
650 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
651 code_byte -= ctxk_bit;
652 DepType dept = (DepType)code_byte;
653 _type = dept;
654 Dependencies::check_valid_dependency_type(dept);
655 int stride = _dep_args[dept];
656 assert(stride == dep_args(dept), "sanity");
657 int skipj = -1;
658 if (ctxk_bit != 0) {
659 skipj = 0; // currently the only context argument is at zero
660 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
661 }
662 for (int j = 0; j < stride; j++) {
663 _xi[j] = (j == skipj)? 0: _bytes.read_int();
664 }
665 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
666 return true;
667 }
668 }
670 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
671 Metadata* o = NULL;
672 if (_code != NULL) {
673 o = _code->metadata_at(i);
674 } else {
675 o = _deps->oop_recorder()->metadata_at(i);
676 }
677 return o;
678 }
680 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
681 return (_code != NULL)
682 ? _code->oop_at(i)
683 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
684 }
686 Metadata* Dependencies::DepStream::argument(int i) {
687 Metadata* result = recorded_metadata_at(argument_index(i));
689 if (result == NULL) { // Explicit context argument can be compressed
690 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
691 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
692 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
693 }
694 }
696 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
697 return result;
698 }
700 oop Dependencies::DepStream::argument_oop(int i) {
701 oop result = recorded_oop_at(argument_index(i));
702 assert(result == NULL || result->is_oop(), "must be");
703 return result;
704 }
706 Klass* Dependencies::DepStream::context_type() {
707 assert(must_be_in_vm(), "raw oops here");
709 // Most dependencies have an explicit context type argument.
710 {
711 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
712 if (ctxkj >= 0) {
713 Metadata* k = argument(ctxkj);
714 assert(k != NULL && k->is_klass(), "type check");
715 return (Klass*)k;
716 }
717 }
719 // Some dependencies are using the klass of the first object
720 // argument as implicit context type (e.g. call_site_target_value).
721 {
722 int ctxkj = dep_implicit_context_arg(type());
723 if (ctxkj >= 0) {
724 Klass* k = argument_oop(ctxkj)->klass();
725 assert(k != NULL && k->is_klass(), "type check");
726 return (Klass*) k;
727 }
728 }
730 // And some dependencies don't have a context type at all,
731 // e.g. evol_method.
732 return NULL;
733 }
735 /// Checking dependencies:
737 // This hierarchy walker inspects subtypes of a given type,
738 // trying to find a "bad" class which breaks a dependency.
739 // Such a class is called a "witness" to the broken dependency.
740 // While searching around, we ignore "participants", which
741 // are already known to the dependency.
742 class ClassHierarchyWalker {
743 public:
744 enum { PARTICIPANT_LIMIT = 3 };
746 private:
747 // optional method descriptor to check for:
748 Symbol* _name;
749 Symbol* _signature;
751 // special classes which are not allowed to be witnesses:
752 Klass* _participants[PARTICIPANT_LIMIT+1];
753 int _num_participants;
755 // cache of method lookups
756 Method* _found_methods[PARTICIPANT_LIMIT+1];
758 // if non-zero, tells how many witnesses to convert to participants
759 int _record_witnesses;
761 void initialize(Klass* participant) {
762 _record_witnesses = 0;
763 _participants[0] = participant;
764 _found_methods[0] = NULL;
765 _num_participants = 0;
766 if (participant != NULL) {
767 // Terminating NULL.
768 _participants[1] = NULL;
769 _found_methods[1] = NULL;
770 _num_participants = 1;
771 }
772 }
774 void initialize_from_method(Method* m) {
775 assert(m != NULL && m->is_method(), "sanity");
776 _name = m->name();
777 _signature = m->signature();
778 }
780 public:
781 // The walker is initialized to recognize certain methods and/or types
782 // as friendly participants.
783 ClassHierarchyWalker(Klass* participant, Method* m) {
784 initialize_from_method(m);
785 initialize(participant);
786 }
787 ClassHierarchyWalker(Method* m) {
788 initialize_from_method(m);
789 initialize(NULL);
790 }
791 ClassHierarchyWalker(Klass* participant = NULL) {
792 _name = NULL;
793 _signature = NULL;
794 initialize(participant);
795 }
797 // This is common code for two searches: One for concrete subtypes,
798 // the other for concrete method implementations and overrides.
799 bool doing_subtype_search() {
800 return _name == NULL;
801 }
803 int num_participants() { return _num_participants; }
804 Klass* participant(int n) {
805 assert((uint)n <= (uint)_num_participants, "oob");
806 return _participants[n];
807 }
809 // Note: If n==num_participants, returns NULL.
810 Method* found_method(int n) {
811 assert((uint)n <= (uint)_num_participants, "oob");
812 Method* fm = _found_methods[n];
813 assert(n == _num_participants || fm != NULL, "proper usage");
814 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
815 return fm;
816 }
818 #ifdef ASSERT
819 // Assert that m is inherited into ctxk, without intervening overrides.
820 // (May return true even if this is not true, in corner cases where we punt.)
821 bool check_method_context(Klass* ctxk, Method* m) {
822 if (m->method_holder() == ctxk)
823 return true; // Quick win.
824 if (m->is_private())
825 return false; // Quick lose. Should not happen.
826 if (!(m->is_public() || m->is_protected()))
827 // The override story is complex when packages get involved.
828 return true; // Must punt the assertion to true.
829 Klass* k = ctxk;
830 Method* lm = k->lookup_method(m->name(), m->signature());
831 if (lm == NULL && k->oop_is_instance()) {
832 // It might be an interface method
833 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
834 m->signature());
835 }
836 if (lm == m)
837 // Method m is inherited into ctxk.
838 return true;
839 if (lm != NULL) {
840 if (!(lm->is_public() || lm->is_protected())) {
841 // Method is [package-]private, so the override story is complex.
842 return true; // Must punt the assertion to true.
843 }
844 if (lm->is_static()) {
845 // Static methods don't override non-static so punt
846 return true;
847 }
848 if ( !Dependencies::is_concrete_method(lm)
849 && !Dependencies::is_concrete_method(m)
850 && lm->method_holder()->is_subtype_of(m->method_holder()))
851 // Method m is overridden by lm, but both are non-concrete.
852 return true;
853 }
854 ResourceMark rm;
855 tty->print_cr("Dependency method not found in the associated context:");
856 tty->print_cr(" context = %s", ctxk->external_name());
857 tty->print( " method = "); m->print_short_name(tty); tty->cr();
858 if (lm != NULL) {
859 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
860 }
861 return false;
862 }
863 #endif
865 void add_participant(Klass* participant) {
866 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
867 int np = _num_participants++;
868 _participants[np] = participant;
869 _participants[np+1] = NULL;
870 _found_methods[np+1] = NULL;
871 }
873 void record_witnesses(int add) {
874 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
875 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
876 _record_witnesses = add;
877 }
879 bool is_witness(Klass* k) {
880 if (doing_subtype_search()) {
881 return Dependencies::is_concrete_klass(k);
882 } else {
883 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
884 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
885 _found_methods[_num_participants] = m;
886 // Note: If add_participant(k) is called,
887 // the method m will already be memoized for it.
888 return true;
889 }
890 }
892 bool is_participant(Klass* k) {
893 if (k == _participants[0]) {
894 return true;
895 } else if (_num_participants <= 1) {
896 return false;
897 } else {
898 return in_list(k, &_participants[1]);
899 }
900 }
901 bool ignore_witness(Klass* witness) {
902 if (_record_witnesses == 0) {
903 return false;
904 } else {
905 --_record_witnesses;
906 add_participant(witness);
907 return true;
908 }
909 }
910 static bool in_list(Klass* x, Klass** list) {
911 for (int i = 0; ; i++) {
912 Klass* y = list[i];
913 if (y == NULL) break;
914 if (y == x) return true;
915 }
916 return false; // not in list
917 }
919 private:
920 // the actual search method:
921 Klass* find_witness_anywhere(Klass* context_type,
922 bool participants_hide_witnesses,
923 bool top_level_call = true);
924 // the spot-checking version:
925 Klass* find_witness_in(KlassDepChange& changes,
926 Klass* context_type,
927 bool participants_hide_witnesses);
928 public:
929 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
930 assert(doing_subtype_search(), "must set up a subtype search");
931 // When looking for unexpected concrete types,
932 // do not look beneath expected ones.
933 const bool participants_hide_witnesses = true;
934 // CX > CC > C' is OK, even if C' is new.
935 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
936 if (changes != NULL) {
937 return find_witness_in(*changes, context_type, participants_hide_witnesses);
938 } else {
939 return find_witness_anywhere(context_type, participants_hide_witnesses);
940 }
941 }
942 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
943 assert(!doing_subtype_search(), "must set up a method definer search");
944 // When looking for unexpected concrete methods,
945 // look beneath expected ones, to see if there are overrides.
946 const bool participants_hide_witnesses = true;
947 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
948 if (changes != NULL) {
949 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
950 } else {
951 return find_witness_anywhere(context_type, !participants_hide_witnesses);
952 }
953 }
954 };
956 #ifndef PRODUCT
957 static int deps_find_witness_calls = 0;
958 static int deps_find_witness_steps = 0;
959 static int deps_find_witness_recursions = 0;
960 static int deps_find_witness_singles = 0;
961 static int deps_find_witness_print = 0; // set to -1 to force a final print
962 static bool count_find_witness_calls() {
963 if (TraceDependencies || LogCompilation) {
964 int pcount = deps_find_witness_print + 1;
965 bool final_stats = (pcount == 0);
966 bool initial_call = (pcount == 1);
967 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
968 if (pcount < 0) pcount = 1; // crude overflow protection
969 deps_find_witness_print = pcount;
970 if (VerifyDependencies && initial_call) {
971 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
972 }
973 if (occasional_print || final_stats) {
974 // Every now and then dump a little info about dependency searching.
975 if (xtty != NULL) {
976 ttyLocker ttyl;
977 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
978 deps_find_witness_calls,
979 deps_find_witness_steps,
980 deps_find_witness_recursions,
981 deps_find_witness_singles);
982 }
983 if (final_stats || (TraceDependencies && WizardMode)) {
984 ttyLocker ttyl;
985 tty->print_cr("Dependency check (find_witness) "
986 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
987 deps_find_witness_calls,
988 deps_find_witness_steps,
989 (double)deps_find_witness_steps / deps_find_witness_calls,
990 deps_find_witness_recursions,
991 deps_find_witness_singles);
992 }
993 }
994 return true;
995 }
996 return false;
997 }
998 #else
999 #define count_find_witness_calls() (0)
1000 #endif //PRODUCT
1003 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1004 Klass* context_type,
1005 bool participants_hide_witnesses) {
1006 assert(changes.involves_context(context_type), "irrelevant dependency");
1007 Klass* new_type = changes.new_type();
1009 (void)count_find_witness_calls();
1010 NOT_PRODUCT(deps_find_witness_singles++);
1012 // Current thread must be in VM (not native mode, as in CI):
1013 assert(must_be_in_vm(), "raw oops here");
1014 // Must not move the class hierarchy during this check:
1015 assert_locked_or_safepoint(Compile_lock);
1017 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1018 if (nof_impls > 1) {
1019 // Avoid this case: *I.m > { A.m, C }; B.m > C
1020 // %%% Until this is fixed more systematically, bail out.
1021 // See corresponding comment in find_witness_anywhere.
1022 return context_type;
1023 }
1025 assert(!is_participant(new_type), "only old classes are participants");
1026 if (participants_hide_witnesses) {
1027 // If the new type is a subtype of a participant, we are done.
1028 for (int i = 0; i < num_participants(); i++) {
1029 Klass* part = participant(i);
1030 if (part == NULL) continue;
1031 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1032 "correct marking of participants, b/c new_type is unique");
1033 if (changes.involves_context(part)) {
1034 // new guy is protected from this check by previous participant
1035 return NULL;
1036 }
1037 }
1038 }
1040 if (is_witness(new_type) &&
1041 !ignore_witness(new_type)) {
1042 return new_type;
1043 }
1045 return NULL;
1046 }
1049 // Walk hierarchy under a context type, looking for unexpected types.
1050 // Do not report participant types, and recursively walk beneath
1051 // them only if participants_hide_witnesses is false.
1052 // If top_level_call is false, skip testing the context type,
1053 // because the caller has already considered it.
1054 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1055 bool participants_hide_witnesses,
1056 bool top_level_call) {
1057 // Current thread must be in VM (not native mode, as in CI):
1058 assert(must_be_in_vm(), "raw oops here");
1059 // Must not move the class hierarchy during this check:
1060 assert_locked_or_safepoint(Compile_lock);
1062 bool do_counts = count_find_witness_calls();
1064 // Check the root of the sub-hierarchy first.
1065 if (top_level_call) {
1066 if (do_counts) {
1067 NOT_PRODUCT(deps_find_witness_calls++);
1068 NOT_PRODUCT(deps_find_witness_steps++);
1069 }
1070 if (is_participant(context_type)) {
1071 if (participants_hide_witnesses) return NULL;
1072 // else fall through to search loop...
1073 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1074 // The context is an abstract class or interface, to start with.
1075 return context_type;
1076 }
1077 }
1079 // Now we must check each implementor and each subclass.
1080 // Use a short worklist to avoid blowing the stack.
1081 // Each worklist entry is a *chain* of subklass siblings to process.
1082 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1083 Klass* chains[CHAINMAX];
1084 int chaini = 0; // index into worklist
1085 Klass* chain; // scratch variable
1086 #define ADD_SUBCLASS_CHAIN(k) { \
1087 assert(chaini < CHAINMAX, "oob"); \
1088 chain = InstanceKlass::cast(k)->subklass(); \
1089 if (chain != NULL) chains[chaini++] = chain; }
1091 // Look for non-abstract subclasses.
1092 // (Note: Interfaces do not have subclasses.)
1093 ADD_SUBCLASS_CHAIN(context_type);
1095 // If it is an interface, search its direct implementors.
1096 // (Their subclasses are additional indirect implementors.
1097 // See InstanceKlass::add_implementor.)
1098 // (Note: nof_implementors is always zero for non-interfaces.)
1099 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1100 if (nof_impls > 1) {
1101 // Avoid this case: *I.m > { A.m, C }; B.m > C
1102 // Here, I.m has 2 concrete implementations, but m appears unique
1103 // as A.m, because the search misses B.m when checking C.
1104 // The inherited method B.m was getting missed by the walker
1105 // when interface 'I' was the starting point.
1106 // %%% Until this is fixed more systematically, bail out.
1107 // (Old CHA had the same limitation.)
1108 return context_type;
1109 }
1110 if (nof_impls > 0) {
1111 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1112 assert(impl != NULL, "just checking");
1113 // If impl is the same as the context_type, then more than one
1114 // implementor has seen. No exact info in this case.
1115 if (impl == context_type) {
1116 return context_type; // report an inexact witness to this sad affair
1117 }
1118 if (do_counts)
1119 { NOT_PRODUCT(deps_find_witness_steps++); }
1120 if (is_participant(impl)) {
1121 if (!participants_hide_witnesses) {
1122 ADD_SUBCLASS_CHAIN(impl);
1123 }
1124 } else if (is_witness(impl) && !ignore_witness(impl)) {
1125 return impl;
1126 } else {
1127 ADD_SUBCLASS_CHAIN(impl);
1128 }
1129 }
1131 // Recursively process each non-trivial sibling chain.
1132 while (chaini > 0) {
1133 Klass* chain = chains[--chaini];
1134 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1135 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1136 if (is_participant(sub)) {
1137 if (participants_hide_witnesses) continue;
1138 // else fall through to process this guy's subclasses
1139 } else if (is_witness(sub) && !ignore_witness(sub)) {
1140 return sub;
1141 }
1142 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1143 // Fast path. (Partially disabled if VerifyDependencies.)
1144 ADD_SUBCLASS_CHAIN(sub);
1145 } else {
1146 // Worklist overflow. Do a recursive call. Should be rare.
1147 // The recursive call will have its own worklist, of course.
1148 // (Note that sub has already been tested, so that there is
1149 // no need for the recursive call to re-test. That's handy,
1150 // since the recursive call sees sub as the context_type.)
1151 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1152 Klass* witness = find_witness_anywhere(sub,
1153 participants_hide_witnesses,
1154 /*top_level_call=*/ false);
1155 if (witness != NULL) return witness;
1156 }
1157 }
1158 }
1160 // No witness found. The dependency remains unbroken.
1161 return NULL;
1162 #undef ADD_SUBCLASS_CHAIN
1163 }
1166 bool Dependencies::is_concrete_klass(Klass* k) {
1167 if (k->is_abstract()) return false;
1168 // %%% We could treat classes which are concrete but
1169 // have not yet been instantiated as virtually abstract.
1170 // This would require a deoptimization barrier on first instantiation.
1171 //if (k->is_not_instantiated()) return false;
1172 return true;
1173 }
1175 bool Dependencies::is_concrete_method(Method* m) {
1176 // Statics are irrelevant to virtual call sites.
1177 if (m->is_static()) return false;
1179 // We could also return false if m does not yet appear to be
1180 // executed, if the VM version supports this distinction also.
1181 // Default methods are considered "concrete" as well.
1182 return !m->is_abstract() &&
1183 !m->is_overpass(); // error functions aren't concrete
1184 }
1187 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1188 if (k->is_interface()) return NULL;
1189 if (k->has_finalizer()) return k;
1190 k = k->subklass();
1191 while (k != NULL) {
1192 Klass* result = find_finalizable_subclass(k);
1193 if (result != NULL) return result;
1194 k = k->next_sibling();
1195 }
1196 return NULL;
1197 }
1200 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1201 if (k->is_abstract()) return false;
1202 // We could also return false if k does not yet appear to be
1203 // instantiated, if the VM version supports this distinction also.
1204 //if (k->is_not_instantiated()) return false;
1205 return true;
1206 }
1208 bool Dependencies::is_concrete_method(ciMethod* m) {
1209 // Statics are irrelevant to virtual call sites.
1210 if (m->is_static()) return false;
1212 // We could also return false if m does not yet appear to be
1213 // executed, if the VM version supports this distinction also.
1214 return !m->is_abstract();
1215 }
1218 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1219 return k->has_finalizable_subclass();
1220 }
1223 // Any use of the contents (bytecodes) of a method must be
1224 // marked by an "evol_method" dependency, if those contents
1225 // can change. (Note: A method is always dependent on itself.)
1226 Klass* Dependencies::check_evol_method(Method* m) {
1227 assert(must_be_in_vm(), "raw oops here");
1228 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1229 // Or is there a now a breakpoint?
1230 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1231 if (m->is_old()
1232 || m->number_of_breakpoints() > 0) {
1233 return m->method_holder();
1234 } else {
1235 return NULL;
1236 }
1237 }
1239 // This is a strong assertion: It is that the given type
1240 // has no subtypes whatever. It is most useful for
1241 // optimizing checks on reflected types or on array types.
1242 // (Checks on types which are derived from real instances
1243 // can be optimized more strongly than this, because we
1244 // know that the checked type comes from a concrete type,
1245 // and therefore we can disregard abstract types.)
1246 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1247 assert(must_be_in_vm(), "raw oops here");
1248 assert_locked_or_safepoint(Compile_lock);
1249 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1250 Klass* sub = ctx->subklass();
1251 if (sub != NULL) {
1252 return sub;
1253 } else if (ctx->nof_implementors() != 0) {
1254 // if it is an interface, it must be unimplemented
1255 // (if it is not an interface, nof_implementors is always zero)
1256 Klass* impl = ctx->implementor();
1257 assert(impl != NULL, "must be set");
1258 return impl;
1259 } else {
1260 return NULL;
1261 }
1262 }
1264 // Test the assertion that conck is the only concrete subtype* of ctxk.
1265 // The type conck itself is allowed to have have further concrete subtypes.
1266 // This allows the compiler to narrow occurrences of ctxk by conck,
1267 // when dealing with the types of actual instances.
1268 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1269 Klass* conck,
1270 KlassDepChange* changes) {
1271 ClassHierarchyWalker wf(conck);
1272 return wf.find_witness_subtype(ctxk, changes);
1273 }
1275 // If a non-concrete class has no concrete subtypes, it is not (yet)
1276 // instantiatable. This can allow the compiler to make some paths go
1277 // dead, if they are gated by a test of the type.
1278 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1279 KlassDepChange* changes) {
1280 // Find any concrete subtype, with no participants:
1281 ClassHierarchyWalker wf;
1282 return wf.find_witness_subtype(ctxk, changes);
1283 }
1286 // If a concrete class has no concrete subtypes, it can always be
1287 // exactly typed. This allows the use of a cheaper type test.
1288 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1289 KlassDepChange* changes) {
1290 // Find any concrete subtype, with only the ctxk as participant:
1291 ClassHierarchyWalker wf(ctxk);
1292 return wf.find_witness_subtype(ctxk, changes);
1293 }
1296 // Find the unique concrete proper subtype of ctxk, or NULL if there
1297 // is more than one concrete proper subtype. If there are no concrete
1298 // proper subtypes, return ctxk itself, whether it is concrete or not.
1299 // The returned subtype is allowed to have have further concrete subtypes.
1300 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1301 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1302 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1303 wf.record_witnesses(1); // Record one other witness when walking.
1304 Klass* wit = wf.find_witness_subtype(ctxk);
1305 if (wit != NULL) return NULL; // Too many witnesses.
1306 Klass* conck = wf.participant(0);
1307 if (conck == NULL) {
1308 #ifndef PRODUCT
1309 // Make sure the dependency mechanism will pass this discovery:
1310 if (VerifyDependencies) {
1311 // Turn off dependency tracing while actually testing deps.
1312 FlagSetting fs(TraceDependencies, false);
1313 if (!Dependencies::is_concrete_klass(ctxk)) {
1314 guarantee(NULL ==
1315 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1316 "verify dep.");
1317 } else {
1318 guarantee(NULL ==
1319 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1320 "verify dep.");
1321 }
1322 }
1323 #endif //PRODUCT
1324 return ctxk; // Return ctxk as a flag for "no subtypes".
1325 } else {
1326 #ifndef PRODUCT
1327 // Make sure the dependency mechanism will pass this discovery:
1328 if (VerifyDependencies) {
1329 // Turn off dependency tracing while actually testing deps.
1330 FlagSetting fs(TraceDependencies, false);
1331 if (!Dependencies::is_concrete_klass(ctxk)) {
1332 guarantee(NULL == (void *)
1333 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1334 "verify dep.");
1335 }
1336 }
1337 #endif //PRODUCT
1338 return conck;
1339 }
1340 }
1342 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1343 // except possibly for further subtypes of k[12] themselves.
1344 // The context type must be abstract. The types k1 and k2 are themselves
1345 // allowed to have further concrete subtypes.
1346 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1347 Klass* ctxk,
1348 Klass* k1,
1349 Klass* k2,
1350 KlassDepChange* changes) {
1351 ClassHierarchyWalker wf;
1352 wf.add_participant(k1);
1353 wf.add_participant(k2);
1354 return wf.find_witness_subtype(ctxk, changes);
1355 }
1357 // Search ctxk for concrete implementations. If there are klen or fewer,
1358 // pack them into the given array and return the number.
1359 // Otherwise, return -1, meaning the given array would overflow.
1360 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1361 // In this search, if ctxk is concrete, it will be reported alone.
1362 // For any type CC reported, no proper subtypes of CC will be reported.
1363 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1364 int klen,
1365 Klass* karray[]) {
1366 ClassHierarchyWalker wf;
1367 wf.record_witnesses(klen);
1368 Klass* wit = wf.find_witness_subtype(ctxk);
1369 if (wit != NULL) return -1; // Too many witnesses.
1370 int num = wf.num_participants();
1371 assert(num <= klen, "oob");
1372 // Pack the result array with the good news.
1373 for (int i = 0; i < num; i++)
1374 karray[i] = wf.participant(i);
1375 #ifndef PRODUCT
1376 // Make sure the dependency mechanism will pass this discovery:
1377 if (VerifyDependencies) {
1378 // Turn off dependency tracing while actually testing deps.
1379 FlagSetting fs(TraceDependencies, false);
1380 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1381 case -1: // ctxk was itself concrete
1382 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1383 break;
1384 case 0:
1385 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1386 "verify dep.");
1387 break;
1388 case 1:
1389 guarantee(NULL == (void *)
1390 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1391 "verify dep.");
1392 break;
1393 case 2:
1394 guarantee(NULL == (void *)
1395 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1396 karray[0],
1397 karray[1]),
1398 "verify dep.");
1399 break;
1400 default:
1401 ShouldNotReachHere(); // klen > 2 yet supported
1402 }
1403 }
1404 #endif //PRODUCT
1405 return num;
1406 }
1408 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1409 // Otherwise, return a class that contains an interfering method.
1410 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1411 KlassDepChange* changes) {
1412 // Here is a missing optimization: If uniqm->is_final(),
1413 // we don't really need to search beneath it for overrides.
1414 // This is probably not important, since we don't use dependencies
1415 // to track final methods. (They can't be "definalized".)
1416 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1417 return wf.find_witness_definer(ctxk, changes);
1418 }
1420 // Find the set of all non-abstract methods under ctxk that match m.
1421 // (The method m must be defined or inherited in ctxk.)
1422 // Include m itself in the set, unless it is abstract.
1423 // If this set has exactly one element, return that element.
1424 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1425 ClassHierarchyWalker wf(m);
1426 assert(wf.check_method_context(ctxk, m), "proper context");
1427 wf.record_witnesses(1);
1428 Klass* wit = wf.find_witness_definer(ctxk);
1429 if (wit != NULL) return NULL; // Too many witnesses.
1430 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1431 if (Dependencies::is_concrete_method(m)) {
1432 if (fm == NULL) {
1433 // It turns out that m was always the only implementation.
1434 fm = m;
1435 } else if (fm != m) {
1436 // Two conflicting implementations after all.
1437 // (This can happen if m is inherited into ctxk and fm overrides it.)
1438 return NULL;
1439 }
1440 }
1441 #ifndef PRODUCT
1442 // Make sure the dependency mechanism will pass this discovery:
1443 if (VerifyDependencies && fm != NULL) {
1444 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1445 "verify dep.");
1446 }
1447 #endif //PRODUCT
1448 return fm;
1449 }
1451 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1452 Method* m1,
1453 Method* m2,
1454 KlassDepChange* changes) {
1455 ClassHierarchyWalker wf(m1);
1456 wf.add_participant(m1->method_holder());
1457 wf.add_participant(m2->method_holder());
1458 return wf.find_witness_definer(ctxk, changes);
1459 }
1461 // Find the set of all non-abstract methods under ctxk that match m[0].
1462 // (The method m[0] must be defined or inherited in ctxk.)
1463 // Include m itself in the set, unless it is abstract.
1464 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1465 // (The length may be zero if no concrete methods are found anywhere.)
1466 // If there are too many concrete methods to fit in marray, return -1.
1467 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1468 int mlen,
1469 Method* marray[]) {
1470 Method* m0 = marray[0];
1471 ClassHierarchyWalker wf(m0);
1472 assert(wf.check_method_context(ctxk, m0), "proper context");
1473 wf.record_witnesses(mlen);
1474 bool participants_hide_witnesses = true;
1475 Klass* wit = wf.find_witness_definer(ctxk);
1476 if (wit != NULL) return -1; // Too many witnesses.
1477 int num = wf.num_participants();
1478 assert(num <= mlen, "oob");
1479 // Keep track of whether m is also part of the result set.
1480 int mfill = 0;
1481 assert(marray[mfill] == m0, "sanity");
1482 if (Dependencies::is_concrete_method(m0))
1483 mfill++; // keep m0 as marray[0], the first result
1484 for (int i = 0; i < num; i++) {
1485 Method* fm = wf.found_method(i);
1486 if (fm == m0) continue; // Already put this guy in the list.
1487 if (mfill == mlen) {
1488 return -1; // Oops. Too many methods after all!
1489 }
1490 marray[mfill++] = fm;
1491 }
1492 #ifndef PRODUCT
1493 // Make sure the dependency mechanism will pass this discovery:
1494 if (VerifyDependencies) {
1495 // Turn off dependency tracing while actually testing deps.
1496 FlagSetting fs(TraceDependencies, false);
1497 switch (mfill) {
1498 case 1:
1499 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1500 "verify dep.");
1501 break;
1502 case 2:
1503 guarantee(NULL == (void *)
1504 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1505 "verify dep.");
1506 break;
1507 default:
1508 ShouldNotReachHere(); // mlen > 2 yet supported
1509 }
1510 }
1511 #endif //PRODUCT
1512 return mfill;
1513 }
1516 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1517 Klass* search_at = ctxk;
1518 if (changes != NULL)
1519 search_at = changes->new_type(); // just look at the new bit
1520 return find_finalizable_subclass(search_at);
1521 }
1524 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1525 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1526 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1527 if (changes == NULL) {
1528 // Validate all CallSites
1529 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1530 return call_site->klass(); // assertion failed
1531 } else {
1532 // Validate the given CallSite
1533 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1534 assert(method_handle != changes->method_handle(), "must be");
1535 return call_site->klass(); // assertion failed
1536 }
1537 }
1538 return NULL; // assertion still valid
1539 }
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 }
1553 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1554 assert_locked_or_safepoint(Compile_lock);
1555 Dependencies::check_valid_dependency_type(type());
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 }
1595 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1596 assert_locked_or_safepoint(Compile_lock);
1597 Dependencies::check_valid_dependency_type(type());
1599 Klass* witness = NULL;
1600 switch (type()) {
1601 case call_site_target_value:
1602 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1603 break;
1604 default:
1605 witness = NULL;
1606 break;
1607 }
1608 trace_and_log_witness(witness);
1609 return witness;
1610 }
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());
1618 // Handle CallSite dependency
1619 if (changes.is_call_site_change())
1620 return check_call_site_dependency(changes.as_call_site_change());
1622 // irrelevant dependency; skip it
1623 return NULL;
1624 }
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 }
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 }
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 }
1701 void KlassDepChange::initialize() {
1702 // entire transaction must be under this lock:
1703 assert_lock_strong(Compile_lock);
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 }
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 }
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 }
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