1 /*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciArrayKlass.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "ci/ciKlass.hpp"
29 #include "ci/ciMethod.hpp"
30 #include "code/dependencies.hpp"
31 #include "compiler/compileLog.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/handles.hpp"
34 #include "runtime/handles.inline.hpp"
35 #include "utilities/copy.hpp"
36
37
38 #ifdef ASSERT
39 static bool must_be_in_vm() {
40 Thread* thread = Thread::current();
41 if (thread->is_Java_thread())
42 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
43 else
44 return true; //something like this: thread->is_VM_thread();
45 }
46 #endif //ASSERT
47
48 void Dependencies::initialize(ciEnv* env) {
49 Arena* arena = env->arena();
50 _oop_recorder = env->oop_recorder();
51 _log = env->log();
52 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
53 DEBUG_ONLY(_deps[end_marker] = NULL);
54 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
55 _deps[i] = new(arena) GrowableArray<DepValue>(arena, 10, 0, DepValue());
56 }
57 _content_bytes = NULL;
58 _size_in_bytes = (size_t)-1;
59
60 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
61 }
62
63 void Dependencies::assert_evol_method(DepValue m) {
64 assert_common_1(evol_method, m);
65 }
66
67 void Dependencies::assert_leaf_type(DepValue ctxk) {
68 if (ctxk.is_array_klass()) {
69 // As a special case, support this assertion on an array type,
70 // which reduces to an assertion on its element type.
71 // Note that this cannot be done with assertions that
72 // relate to concreteness or abstractness.
73 if (!ctxk.is_array_element_instance_klass()) return; // Ex: int[][]
74 ctxk = ctxk.array_element_instance_klass();
75 //if (ctxk->is_final()) return; // Ex: String[][]
76 }
77 check_ctxk(ctxk);
78 assert_common_1(leaf_type, ctxk);
79 }
80
81 void Dependencies::assert_abstract_with_unique_concrete_subtype(DepValue ctxk, DepValue conck) {
82 check_ctxk_abstract(ctxk);
83 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
84 }
85
86 void Dependencies::assert_abstract_with_no_concrete_subtype(DepValue ctxk) {
87 check_ctxk_abstract(ctxk);
88 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
89 }
90
91 void Dependencies::assert_concrete_with_no_concrete_subtype(DepValue ctxk) {
92 check_ctxk_concrete(ctxk);
93 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
94 }
95
96 void Dependencies::assert_unique_concrete_method(DepValue ctxk, DepValue uniqm) {
97 check_ctxk(ctxk);
98 assert_common_2(unique_concrete_method, ctxk, uniqm);
99 }
100
101 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(DepValue ctxk, DepValue k1, DepValue k2) {
102 check_ctxk(ctxk);
103 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
104 }
105
106 void Dependencies::assert_exclusive_concrete_methods(DepValue ctxk, DepValue m1, DepValue m2) {
107 check_ctxk(ctxk);
108 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
109 }
110
111 void Dependencies::assert_has_no_finalizable_subclasses(DepValue ctxk) {
112 check_ctxk(ctxk);
113 assert_common_1(no_finalizable_subclasses, ctxk);
114 }
115
116 void Dependencies::assert_call_site_target_value(DepValue call_site, DepValue method_handle) {
117 check_ctxk(call_site);
118 assert_common_2(call_site_target_value, call_site, method_handle);
119 }
120
121 // Helper function. If we are adding a new dep. under ctxk2,
122 // try to find an old dep. under a broader* ctxk1. If there is
123 //
124 bool Dependencies::maybe_merge_ctxk(GrowableArray<DepValue>* deps,
125 int ctxk_i, DepValue ctxk2) {
126 DepValue ctxk1 = deps->at(ctxk_i);
127 if (ctxk2.is_subtype_of(ctxk1)) {
128 return true; // success, and no need to change
129 } else if (ctxk1.is_subtype_of(ctxk2)) {
130 // new context class fully subsumes previous one
131 deps->at_put(ctxk_i, ctxk2);
132 return true;
133 } else {
134 return false;
135 }
136 }
137
138 void Dependencies::assert_common_1(DepType dept, DepValue x) {
139 assert(dep_args(dept) == 1, "sanity");
140 log_dependency(dept, x);
141 GrowableArray<DepValue>* deps = _deps[dept];
142
143 // see if the same (or a similar) dep is already recorded
144 if (note_dep_seen(dept, x)) {
145 assert(deps->find(x) >= 0, "sanity");
146 } else {
147 deps->append(x);
148 }
149 }
150
151 void Dependencies::assert_common_2(DepType dept,
152 DepValue x0, DepValue x1) {
153 assert(dep_args(dept) == 2, "sanity");
154 log_dependency(dept, x0, x1);
155 GrowableArray<DepValue>* deps = _deps[dept];
156
157 // see if the same (or a similar) dep is already recorded
158 bool has_ctxk = has_explicit_context_arg(dept);
159 if (has_ctxk) {
160 assert(dep_context_arg(dept) == 0, "sanity");
161 if (note_dep_seen(dept, x1)) {
162 // look in this bucket for redundant assertions
163 const int stride = 2;
164 for (int i = deps->length(); (i -= stride) >= 0; ) {
165 DepValue y1 = deps->at(i+1);
166 if (x1 == y1) { // same subject; check the context
167 if (maybe_merge_ctxk(deps, i+0, x0)) {
168 return;
169 }
170 }
171 }
172 }
173 } else {
174 assert(dep_implicit_context_arg(dept) == 0, "sanity");
175 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
176 // look in this bucket for redundant assertions
177 const int stride = 2;
178 for (int i = deps->length(); (i -= stride) >= 0; ) {
179 DepValue y0 = deps->at(i+0);
180 DepValue y1 = deps->at(i+1);
181 if (x0 == y0 && x1 == y1) {
182 return;
183 }
184 }
185 }
186 }
187
188 // append the assertion in the correct bucket:
189 deps->append(x0);
190 deps->append(x1);
191 }
192
193 void Dependencies::assert_common_3(DepType dept,
194 DepValue ctxk, DepValue x, DepValue x2) {
195 assert(dep_context_arg(dept) == 0, "sanity");
196 assert(dep_args(dept) == 3, "sanity");
197 log_dependency(dept, ctxk, x, x2);
198 GrowableArray<DepValue>* deps = _deps[dept];
199
200 // try to normalize an unordered pair:
201 bool swap = false;
202 switch (dept) {
203 case abstract_with_exclusive_concrete_subtypes_2:
204 swap = (x.ident() > x2.ident() && x != ctxk);
205 break;
206 case exclusive_concrete_methods_2:
207 swap = (x.ident() > x2.ident() && x.method_holder() != ctxk);
208 break;
209 }
210 if (swap) { DepValue t = x; x = x2; x2 = t; }
211
212 // see if the same (or a similar) dep is already recorded
213 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
214 // look in this bucket for redundant assertions
215 const int stride = 3;
216 for (int i = deps->length(); (i -= stride) >= 0; ) {
217 DepValue y = deps->at(i+1);
218 DepValue y2 = deps->at(i+2);
219 if (x == y && x2 == y2) { // same subjects; check the context
220 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
221 return;
222 }
223 }
224 }
225 }
226 // append the assertion in the correct bucket:
227 deps->append(ctxk);
228 deps->append(x);
229 deps->append(x2);
230 }
231
232 /// Support for encoding dependencies into an nmethod:
233
234 void Dependencies::copy_to(nmethod* nm) {
235 address beg = nm->dependencies_begin();
236 address end = nm->dependencies_end();
237 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
238 Copy::disjoint_words((HeapWord*) content_bytes(),
239 (HeapWord*) beg,
240 size_in_bytes() / sizeof(HeapWord));
241 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
242 }
243
244 static int sort_dep(DepValue* p1, DepValue* p2, int narg) {
245 for (int i = 0; i < narg; i++) {
246 int diff = p1[i].ident() - p2[i].ident();
247 if (diff != 0) return diff;
248 }
249 return 0;
250 }
251 static int sort_dep_arg_1(DepValue* p1, DepValue* p2)
252 { return sort_dep(p1, p2, 1); }
253 static int sort_dep_arg_2(DepValue* p1, DepValue* p2)
254 { return sort_dep(p1, p2, 2); }
255 static int sort_dep_arg_3(DepValue* p1, DepValue* p2)
256 { return sort_dep(p1, p2, 3); }
257
258 void Dependencies::sort_all_deps() {
259 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
260 DepType dept = (DepType)deptv;
261 GrowableArray<DepValue>* deps = _deps[dept];
262 if (deps->length() <= 1) continue;
263 switch (dep_args(dept)) {
264 case 1: deps->sort(sort_dep_arg_1, 1); break;
265 case 2: deps->sort(sort_dep_arg_2, 2); break;
266 case 3: deps->sort(sort_dep_arg_3, 3); break;
267 default: ShouldNotReachHere();
268 }
269 }
270 }
271
272 size_t Dependencies::estimate_size_in_bytes() {
273 size_t est_size = 100;
274 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
275 DepType dept = (DepType)deptv;
276 GrowableArray<DepValue>* deps = _deps[dept];
277 est_size += deps->length()*2; // tags and argument(s)
278 }
279 return est_size;
280 }
281
282 DepValue Dependencies::ctxk_encoded_as_null(DepType dept, DepValue x) {
283 switch (dept) {
284 case abstract_with_exclusive_concrete_subtypes_2:
285 return x;
286 case unique_concrete_method:
287 case exclusive_concrete_methods_2:
288 return x.method_holder();
289 }
290 return NULL; // let NULL be NULL
291 }
292
293 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
294 assert(must_be_in_vm(), "raw oops here");
295 switch (dept) {
296 case abstract_with_exclusive_concrete_subtypes_2:
297 assert(x->is_klass(), "sanity");
298 return (Klass*) x;
299 case unique_concrete_method:
300 case exclusive_concrete_methods_2:
301 assert(x->is_method(), "sanity");
302 return ((Method*)x)->method_holder();
303 }
304 return NULL; // let NULL be NULL
305 }
306
307 void Dependencies::encode_content_bytes() {
308 sort_all_deps();
309
310 // cast is safe, no deps can overflow INT_MAX
311 CompressedWriteStream bytes((int)estimate_size_in_bytes());
312
313 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
314 DepType dept = (DepType)deptv;
315 GrowableArray<DepValue>* deps = _deps[dept];
316 if (deps->length() == 0) continue;
317 int stride = dep_args(dept);
318 int ctxkj = dep_context_arg(dept); // -1 if no context arg
319 assert(stride > 0, "sanity");
320 for (int i = 0; i < deps->length(); i += stride) {
321 jbyte code_byte = (jbyte)dept;
322 int skipj = -1;
323 if (ctxkj >= 0 && ctxkj+1 < stride) {
324 DepValue ctxk = deps->at(i+ctxkj+0);
325 DepValue x = deps->at(i+ctxkj+1); // following argument
326 if (ctxk == ctxk_encoded_as_null(dept, x)) {
327 skipj = ctxkj; // we win: maybe one less oop to keep track of
328 code_byte |= default_context_type_bit;
329 }
330 }
331 bytes.write_byte(code_byte);
332 for (int j = 0; j < stride; j++) {
333 if (j == skipj) continue;
334 DepValue v = deps->at(i+j);
335 bytes.write_int(v.idx(_oop_recorder));
336 }
337 }
338 }
339
340 // write a sentinel byte to mark the end
341 bytes.write_byte(end_marker);
342
343 // round it out to a word boundary
344 while (bytes.position() % sizeof(HeapWord) != 0) {
345 bytes.write_byte(end_marker);
346 }
347
348 // check whether the dept byte encoding really works
349 assert((jbyte)default_context_type_bit != 0, "byte overflow");
350
351 _content_bytes = bytes.buffer();
352 _size_in_bytes = bytes.position();
353 }
354
355
356 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
357 "end_marker",
358 "evol_method",
359 "leaf_type",
360 "abstract_with_unique_concrete_subtype",
361 "abstract_with_no_concrete_subtype",
362 "concrete_with_no_concrete_subtype",
363 "unique_concrete_method",
364 "abstract_with_exclusive_concrete_subtypes_2",
365 "exclusive_concrete_methods_2",
366 "no_finalizable_subclasses",
367 "call_site_target_value"
368 };
369
370 int Dependencies::_dep_args[TYPE_LIMIT] = {
371 -1,// end_marker
372 1, // evol_method m
373 1, // leaf_type ctxk
374 2, // abstract_with_unique_concrete_subtype ctxk, k
375 1, // abstract_with_no_concrete_subtype ctxk
376 1, // concrete_with_no_concrete_subtype ctxk
377 2, // unique_concrete_method ctxk, m
378 3, // unique_concrete_subtypes_2 ctxk, k1, k2
379 3, // unique_concrete_methods_2 ctxk, m1, m2
380 1, // no_finalizable_subclasses ctxk
381 2 // call_site_target_value call_site, method_handle
382 };
383
384 const char* Dependencies::dep_name(Dependencies::DepType dept) {
385 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
386 return _dep_name[dept];
387 }
388
389 int Dependencies::dep_args(Dependencies::DepType dept) {
390 if (!dept_in_mask(dept, all_types)) return -1;
391 return _dep_args[dept];
392 }
393
394 void Dependencies::check_valid_dependency_type(DepType dept) {
395 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
396 }
397
398 // for the sake of the compiler log, print out current dependencies:
399 void Dependencies::log_all_dependencies() {
400 if (log() == NULL) return;
401 DepValue args[max_arg_count];
402 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
403 DepType dept = (DepType)deptv;
404 GrowableArray<DepValue>* deps = _deps[dept];
405 if (deps->length() == 0) continue;
406 int stride = dep_args(dept);
407 for (int i = 0; i < deps->length(); i += stride) {
408 for (int j = 0; j < stride; j++) {
409 // flush out the identities before printing
410 args[j] = deps->at(i+j);
411 }
412 write_dependency_to(log(), dept, stride, args);
413 }
414 }
415 }
416
417 void Dependencies::write_dependency_to(CompileLog* log,
418 DepType dept,
419 int nargs, DepArgument args[],
420 Klass* witness) {
421 if (log == NULL) {
422 return;
423 }
424 ciEnv* env = ciEnv::current();
425 DepValue ciargs[max_arg_count];
426 assert(nargs <= max_arg_count, "oob");
427 for (int j = 0; j < nargs; j++) {
428 if (args[j].is_oop()) {
429 ciargs[j] = DepValue(env->get_object(args[j].oop_value()));
430 } else {
431 ciargs[j] = DepValue(env->get_metadata(args[j].metadata_value()));
432 }
433 }
434 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
435 }
436
437 void Dependencies::write_dependency_to(CompileLog* log,
438 DepType dept,
439 int nargs, DepValue args[],
440 Klass* witness) {
441 if (log == NULL) return;
442 assert(nargs <= max_arg_count, "oob");
443 int argids[max_arg_count];
444 int ctxkj = dep_context_arg(dept); // -1 if no context arg
445 int j;
446 for (j = 0; j < nargs; j++) {
447 argids[j] = args[j].log_identify(log);
448 }
449 if (witness != NULL) {
450 log->begin_elem("dependency_failed");
451 } else {
452 log->begin_elem("dependency");
453 }
454 log->print(" type='%s'", dep_name(dept));
455 if (ctxkj >= 0) {
456 log->print(" ctxk='%d'", argids[ctxkj]);
457 }
458 // write remaining arguments, if any.
459 for (j = 0; j < nargs; j++) {
460 if (j == ctxkj) continue; // already logged
461 if (j == 1) {
462 log->print( " x='%d'", argids[j]);
463 } else {
464 log->print(" x%d='%d'", j, argids[j]);
465 }
466 }
467 if (witness != NULL) {
468 log->object("witness", witness);
469 log->stamp();
470 }
471 log->end_elem();
472 }
473
474 void Dependencies::write_dependency_to(xmlStream* xtty,
475 DepType dept,
476 int nargs, DepArgument args[],
477 Klass* witness) {
478 if (xtty == NULL) return;
479 ttyLocker ttyl;
480 int ctxkj = dep_context_arg(dept); // -1 if no context arg
481 if (witness != NULL) {
482 xtty->begin_elem("dependency_failed");
483 } else {
484 xtty->begin_elem("dependency");
485 }
486 xtty->print(" type='%s'", dep_name(dept));
487 if (ctxkj >= 0) {
488 xtty->object("ctxk", args[ctxkj].metadata_value());
489 }
490 // write remaining arguments, if any.
491 for (int j = 0; j < nargs; j++) {
492 if (j == ctxkj) continue; // already logged
493 if (j == 1) {
494 if (args[j].is_oop()) {
495 xtty->object("x", args[j].oop_value());
496 } else {
497 xtty->object("x", args[j].metadata_value());
498 }
499 } else {
500 char xn[10]; sprintf(xn, "x%d", j);
501 if (args[j].is_oop()) {
502 xtty->object(xn, args[j].oop_value());
503 } else {
504 xtty->object(xn, args[j].metadata_value());
505 }
506 }
507 }
508 if (witness != NULL) {
509 xtty->object("witness", witness);
510 xtty->stamp();
511 }
512 xtty->end_elem();
513 }
514
515 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[],
516 Klass* witness) {
517 ResourceMark rm;
518 ttyLocker ttyl; // keep the following output all in one block
519 tty->print_cr("%s of type %s",
520 (witness == NULL)? "Dependency": "Failed dependency",
521 dep_name(dept));
522 // print arguments
523 int ctxkj = dep_context_arg(dept); // -1 if no context arg
524 for (int j = 0; j < nargs; j++) {
525 DepArgument arg = args[j];
526 bool put_star = false;
527 if (arg.is_null()) continue;
528 const char* what;
529 if (j == ctxkj) {
530 assert(arg.is_metadata(), "must be");
531 what = "context";
532 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
533 } else if (arg.is_method()) {
534 what = "method ";
535 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
536 } else if (arg.is_klass()) {
537 what = "class ";
538 } else {
539 what = "object ";
540 }
541 tty->print(" %s = %s", what, (put_star? "*": ""));
542 if (arg.is_klass())
543 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
544 else if (arg.is_method())
545 ((Method*)arg.metadata_value())->print_value();
546 else
547 ShouldNotReachHere(); // Provide impl for this type.
548 tty->cr();
549 }
550 if (witness != NULL) {
551 bool put_star = !Dependencies::is_concrete_klass(witness);
552 tty->print_cr(" witness = %s%s",
553 (put_star? "*": ""),
554 witness->external_name());
555 }
556 }
557
558 void Dependencies::DepStream::log_dependency(Klass* witness) {
559 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
560 ResourceMark rm;
561 int nargs = argument_count();
562 DepArgument args[max_arg_count];
563 for (int j = 0; j < nargs; j++) {
564 if (type() == call_site_target_value) {
565 args[j] = argument_oop(j);
566 } else {
567 args[j] = argument(j);
568 }
569 }
570 if (_deps != NULL && _deps->log() != NULL) {
571 Dependencies::write_dependency_to(_deps->log(),
572 type(), nargs, args, witness);
573 } else {
574 Dependencies::write_dependency_to(xtty,
575 type(), nargs, args, witness);
576 }
577 }
578
579 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
580 int nargs = argument_count();
581 DepArgument args[max_arg_count];
582 for (int j = 0; j < nargs; j++) {
583 args[j] = argument(j);
584 }
585 Dependencies::print_dependency(type(), nargs, args, witness);
586 if (verbose) {
587 if (_code != NULL) {
588 tty->print(" code: ");
589 _code->print_value_on(tty);
590 tty->cr();
591 }
592 }
593 }
594
595
596 /// Dependency stream support (decodes dependencies from an nmethod):
597
598 #ifdef ASSERT
599 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
600 assert(must_be_in_vm(), "raw oops here");
601 _byte_limit = byte_limit;
602 _type = (DepType)(end_marker-1); // defeat "already at end" assert
603 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
604 }
605 #endif //ASSERT
606
607 bool Dependencies::DepStream::next() {
608 assert(_type != end_marker, "already at end");
609 if (_bytes.position() == 0 && _code != NULL
610 && _code->dependencies_size() == 0) {
611 // Method has no dependencies at all.
612 return false;
613 }
614 int code_byte = (_bytes.read_byte() & 0xFF);
615 if (code_byte == end_marker) {
616 DEBUG_ONLY(_type = end_marker);
617 return false;
618 } else {
619 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
620 code_byte -= ctxk_bit;
621 DepType dept = (DepType)code_byte;
622 _type = dept;
623 Dependencies::check_valid_dependency_type(dept);
624 int stride = _dep_args[dept];
625 assert(stride == dep_args(dept), "sanity");
626 int skipj = -1;
627 if (ctxk_bit != 0) {
628 skipj = 0; // currently the only context argument is at zero
629 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
630 }
631 for (int j = 0; j < stride; j++) {
632 _xi[j] = (j == skipj)? 0: _bytes.read_int();
633 }
634 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
635 return true;
636 }
637 }
638
639 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
640 Metadata* o = NULL;
641 if (_code != NULL) {
642 o = _code->metadata_at(i);
643 } else {
644 o = _deps->oop_recorder()->metadata_at(i);
645 }
646 assert(o == NULL || o->is_metaspace_object(),
647 err_msg("Should be metadata " PTR_FORMAT, o));
648 return o;
649 }
650
651 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
652 return (_code != NULL)
653 ? _code->oop_at(i)
654 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
655 }
656
657 Metadata* Dependencies::DepStream::argument(int i) {
658 Metadata* result = recorded_metadata_at(argument_index(i));
659
660 if (result == NULL) { // Explicit context argument can be compressed
661 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
662 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
663 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
664 }
665 }
666
667 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
668 return result;
669 }
670
671 oop Dependencies::DepStream::argument_oop(int i) {
672 oop result = recorded_oop_at(argument_index(i));
673 assert(result == NULL || result->is_oop(), "must be");
674 return result;
675 }
676
677 Klass* Dependencies::DepStream::context_type() {
678 assert(must_be_in_vm(), "raw oops here");
679
680 // Most dependencies have an explicit context type argument.
681 {
682 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
683 if (ctxkj >= 0) {
684 Metadata* k = argument(ctxkj);
685 assert(k != NULL && k->is_klass(), "type check");
686 return (Klass*)k;
687 }
688 }
689
690 // Some dependencies are using the klass of the first object
691 // argument as implicit context type (e.g. call_site_target_value).
692 {
693 int ctxkj = dep_implicit_context_arg(type());
694 if (ctxkj >= 0) {
695 Klass* k = argument_oop(ctxkj)->klass();
696 assert(k != NULL && k->is_klass(), "type check");
697 return (Klass*) k;
698 }
699 }
700
701 // And some dependencies don't have a context type at all,
702 // e.g. evol_method.
703 return NULL;
704 }
705
706 /// Checking dependencies:
707
708 // This hierarchy walker inspects subtypes of a given type,
709 // trying to find a "bad" class which breaks a dependency.
710 // Such a class is called a "witness" to the broken dependency.
711 // While searching around, we ignore "participants", which
712 // are already known to the dependency.
713 class ClassHierarchyWalker {
714 public:
715 enum { PARTICIPANT_LIMIT = 3 };
716
717 private:
718 // optional method descriptor to check for:
719 Symbol* _name;
720 Symbol* _signature;
721
722 // special classes which are not allowed to be witnesses:
723 Klass* _participants[PARTICIPANT_LIMIT+1];
724 int _num_participants;
725
726 // cache of method lookups
727 Method* _found_methods[PARTICIPANT_LIMIT+1];
728
729 // if non-zero, tells how many witnesses to convert to participants
730 int _record_witnesses;
731
732 void initialize(Klass* participant) {
733 _record_witnesses = 0;
734 _participants[0] = participant;
735 _found_methods[0] = NULL;
736 _num_participants = 0;
737 if (participant != NULL) {
738 // Terminating NULL.
739 _participants[1] = NULL;
740 _found_methods[1] = NULL;
741 _num_participants = 1;
742 }
743 }
744
745 void initialize_from_method(Method* m) {
746 assert(m != NULL && m->is_method(), "sanity");
747 _name = m->name();
748 _signature = m->signature();
749 }
750
751 public:
752 // The walker is initialized to recognize certain methods and/or types
753 // as friendly participants.
754 ClassHierarchyWalker(Klass* participant, Method* m) {
755 initialize_from_method(m);
756 initialize(participant);
757 }
758 ClassHierarchyWalker(Method* m) {
759 initialize_from_method(m);
760 initialize(NULL);
761 }
762 ClassHierarchyWalker(Klass* participant = NULL) {
763 _name = NULL;
764 _signature = NULL;
765 initialize(participant);
766 }
767
768 // This is common code for two searches: One for concrete subtypes,
769 // the other for concrete method implementations and overrides.
770 bool doing_subtype_search() {
771 return _name == NULL;
772 }
773
774 int num_participants() { return _num_participants; }
775 Klass* participant(int n) {
776 assert((uint)n <= (uint)_num_participants, "oob");
777 return _participants[n];
778 }
779
780 // Note: If n==num_participants, returns NULL.
781 Method* found_method(int n) {
782 assert((uint)n <= (uint)_num_participants, "oob");
783 Method* fm = _found_methods[n];
784 assert(n == _num_participants || fm != NULL, "proper usage");
785 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
786 return fm;
787 }
788
789 #ifdef ASSERT
790 // Assert that m is inherited into ctxk, without intervening overrides.
791 // (May return true even if this is not true, in corner cases where we punt.)
792 bool check_method_context(Klass* ctxk, Method* m) {
793 if (m->method_holder() == ctxk)
794 return true; // Quick win.
795 if (m->is_private())
796 return false; // Quick lose. Should not happen.
797 if (!(m->is_public() || m->is_protected()))
798 // The override story is complex when packages get involved.
799 return true; // Must punt the assertion to true.
800 Klass* k = ctxk;
801 Method* lm = k->lookup_method(m->name(), m->signature());
802 if (lm == NULL && k->oop_is_instance()) {
803 // It might be an interface method
804 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
805 m->signature());
806 }
807 if (lm == m)
808 // Method m is inherited into ctxk.
809 return true;
810 if (lm != NULL) {
811 if (!(lm->is_public() || lm->is_protected())) {
812 // Method is [package-]private, so the override story is complex.
813 return true; // Must punt the assertion to true.
814 }
815 if (lm->is_static()) {
816 // Static methods don't override non-static so punt
817 return true;
818 }
819 if ( !Dependencies::is_concrete_method(lm)
820 && !Dependencies::is_concrete_method(m)
821 && lm->method_holder()->is_subtype_of(m->method_holder()))
822 // Method m is overridden by lm, but both are non-concrete.
823 return true;
824 }
825 ResourceMark rm;
826 tty->print_cr("Dependency method not found in the associated context:");
827 tty->print_cr(" context = %s", ctxk->external_name());
828 tty->print( " method = "); m->print_short_name(tty); tty->cr();
829 if (lm != NULL) {
830 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
831 }
832 return false;
833 }
834 #endif
835
836 void add_participant(Klass* participant) {
837 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
838 int np = _num_participants++;
839 _participants[np] = participant;
840 _participants[np+1] = NULL;
841 _found_methods[np+1] = NULL;
842 }
843
844 void record_witnesses(int add) {
845 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
846 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
847 _record_witnesses = add;
848 }
849
850 bool is_witness(Klass* k) {
851 if (doing_subtype_search()) {
852 return Dependencies::is_concrete_klass(k);
853 } else {
854 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
855 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
856 _found_methods[_num_participants] = m;
857 // Note: If add_participant(k) is called,
858 // the method m will already be memoized for it.
859 return true;
860 }
861 }
862
863 bool is_participant(Klass* k) {
864 if (k == _participants[0]) {
865 return true;
866 } else if (_num_participants <= 1) {
867 return false;
868 } else {
869 return in_list(k, &_participants[1]);
870 }
871 }
872 bool ignore_witness(Klass* witness) {
873 if (_record_witnesses == 0) {
874 return false;
875 } else {
876 --_record_witnesses;
877 add_participant(witness);
878 return true;
879 }
880 }
881 static bool in_list(Klass* x, Klass** list) {
882 for (int i = 0; ; i++) {
883 Klass* y = list[i];
884 if (y == NULL) break;
885 if (y == x) return true;
886 }
887 return false; // not in list
888 }
889
890 private:
891 // the actual search method:
892 Klass* find_witness_anywhere(Klass* context_type,
893 bool participants_hide_witnesses,
894 bool top_level_call = true);
895 // the spot-checking version:
896 Klass* find_witness_in(KlassDepChange& changes,
897 Klass* context_type,
898 bool participants_hide_witnesses);
899 public:
900 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
901 assert(doing_subtype_search(), "must set up a subtype search");
902 // When looking for unexpected concrete types,
903 // do not look beneath expected ones.
904 const bool participants_hide_witnesses = true;
905 // CX > CC > C' is OK, even if C' is new.
906 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
907 if (changes != NULL) {
908 return find_witness_in(*changes, context_type, participants_hide_witnesses);
909 } else {
910 return find_witness_anywhere(context_type, participants_hide_witnesses);
911 }
912 }
913 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
914 assert(!doing_subtype_search(), "must set up a method definer search");
915 // When looking for unexpected concrete methods,
916 // look beneath expected ones, to see if there are overrides.
917 const bool participants_hide_witnesses = true;
918 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
919 if (changes != NULL) {
920 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
921 } else {
922 return find_witness_anywhere(context_type, !participants_hide_witnesses);
923 }
924 }
925 };
926
927 #ifndef PRODUCT
928 static int deps_find_witness_calls = 0;
929 static int deps_find_witness_steps = 0;
930 static int deps_find_witness_recursions = 0;
931 static int deps_find_witness_singles = 0;
932 static int deps_find_witness_print = 0; // set to -1 to force a final print
933 static bool count_find_witness_calls() {
934 if (TraceDependencies || LogCompilation) {
935 int pcount = deps_find_witness_print + 1;
936 bool final_stats = (pcount == 0);
937 bool initial_call = (pcount == 1);
938 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
939 if (pcount < 0) pcount = 1; // crude overflow protection
940 deps_find_witness_print = pcount;
941 if (VerifyDependencies && initial_call) {
942 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
943 }
944 if (occasional_print || final_stats) {
945 // Every now and then dump a little info about dependency searching.
946 if (xtty != NULL) {
947 ttyLocker ttyl;
948 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
949 deps_find_witness_calls,
950 deps_find_witness_steps,
951 deps_find_witness_recursions,
952 deps_find_witness_singles);
953 }
954 if (final_stats || (TraceDependencies && WizardMode)) {
955 ttyLocker ttyl;
956 tty->print_cr("Dependency check (find_witness) "
957 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
958 deps_find_witness_calls,
959 deps_find_witness_steps,
960 (double)deps_find_witness_steps / deps_find_witness_calls,
961 deps_find_witness_recursions,
962 deps_find_witness_singles);
963 }
964 }
965 return true;
966 }
967 return false;
968 }
969 #else
970 #define count_find_witness_calls() (0)
971 #endif //PRODUCT
972
973
974 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
975 Klass* context_type,
976 bool participants_hide_witnesses) {
977 assert(changes.involves_context(context_type), "irrelevant dependency");
978 Klass* new_type = changes.new_type();
979
980 (void)count_find_witness_calls();
981 NOT_PRODUCT(deps_find_witness_singles++);
982
983 // Current thread must be in VM (not native mode, as in CI):
984 assert(must_be_in_vm(), "raw oops here");
985 // Must not move the class hierarchy during this check:
986 assert_locked_or_safepoint(Compile_lock);
987
988 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
989 if (nof_impls > 1) {
990 // Avoid this case: *I.m > { A.m, C }; B.m > C
991 // %%% Until this is fixed more systematically, bail out.
992 // See corresponding comment in find_witness_anywhere.
993 return context_type;
994 }
995
996 assert(!is_participant(new_type), "only old classes are participants");
997 if (participants_hide_witnesses) {
998 // If the new type is a subtype of a participant, we are done.
999 for (int i = 0; i < num_participants(); i++) {
1000 Klass* part = participant(i);
1001 if (part == NULL) continue;
1002 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1003 "correct marking of participants, b/c new_type is unique");
1004 if (changes.involves_context(part)) {
1005 // new guy is protected from this check by previous participant
1006 return NULL;
1007 }
1008 }
1009 }
1010
1011 if (is_witness(new_type) &&
1012 !ignore_witness(new_type)) {
1013 return new_type;
1014 }
1015
1016 return NULL;
1017 }
1018
1019
1020 // Walk hierarchy under a context type, looking for unexpected types.
1021 // Do not report participant types, and recursively walk beneath
1022 // them only if participants_hide_witnesses is false.
1023 // If top_level_call is false, skip testing the context type,
1024 // because the caller has already considered it.
1025 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1026 bool participants_hide_witnesses,
1027 bool top_level_call) {
1028 // Current thread must be in VM (not native mode, as in CI):
1029 assert(must_be_in_vm(), "raw oops here");
1030 // Must not move the class hierarchy during this check:
1031 assert_locked_or_safepoint(Compile_lock);
1032
1033 bool do_counts = count_find_witness_calls();
1034
1035 // Check the root of the sub-hierarchy first.
1036 if (top_level_call) {
1037 if (do_counts) {
1038 NOT_PRODUCT(deps_find_witness_calls++);
1039 NOT_PRODUCT(deps_find_witness_steps++);
1040 }
1041 if (is_participant(context_type)) {
1042 if (participants_hide_witnesses) return NULL;
1043 // else fall through to search loop...
1044 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1045 // The context is an abstract class or interface, to start with.
1046 return context_type;
1047 }
1048 }
1049
1050 // Now we must check each implementor and each subclass.
1051 // Use a short worklist to avoid blowing the stack.
1052 // Each worklist entry is a *chain* of subklass siblings to process.
1053 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1054 Klass* chains[CHAINMAX];
1055 int chaini = 0; // index into worklist
1056 Klass* chain; // scratch variable
1057 #define ADD_SUBCLASS_CHAIN(k) { \
1058 assert(chaini < CHAINMAX, "oob"); \
1059 chain = InstanceKlass::cast(k)->subklass(); \
1060 if (chain != NULL) chains[chaini++] = chain; }
1061
1062 // Look for non-abstract subclasses.
1063 // (Note: Interfaces do not have subclasses.)
1064 ADD_SUBCLASS_CHAIN(context_type);
1065
1066 // If it is an interface, search its direct implementors.
1067 // (Their subclasses are additional indirect implementors.
1068 // See InstanceKlass::add_implementor.)
1069 // (Note: nof_implementors is always zero for non-interfaces.)
1070 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1071 if (nof_impls > 1) {
1072 // Avoid this case: *I.m > { A.m, C }; B.m > C
1073 // Here, I.m has 2 concrete implementations, but m appears unique
1074 // as A.m, because the search misses B.m when checking C.
1075 // The inherited method B.m was getting missed by the walker
1076 // when interface 'I' was the starting point.
1077 // %%% Until this is fixed more systematically, bail out.
1078 // (Old CHA had the same limitation.)
1079 return context_type;
1080 }
1081 if (nof_impls > 0) {
1082 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1083 assert(impl != NULL, "just checking");
1084 // If impl is the same as the context_type, then more than one
1085 // implementor has seen. No exact info in this case.
1086 if (impl == context_type) {
1087 return context_type; // report an inexact witness to this sad affair
1088 }
1089 if (do_counts)
1090 { NOT_PRODUCT(deps_find_witness_steps++); }
1091 if (is_participant(impl)) {
1092 if (!participants_hide_witnesses) {
1093 ADD_SUBCLASS_CHAIN(impl);
1094 }
1095 } else if (is_witness(impl) && !ignore_witness(impl)) {
1096 return impl;
1097 } else {
1098 ADD_SUBCLASS_CHAIN(impl);
1099 }
1100 }
1101
1102 // Recursively process each non-trivial sibling chain.
1103 while (chaini > 0) {
1104 Klass* chain = chains[--chaini];
1105 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1106 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1107 if (is_participant(sub)) {
1108 if (participants_hide_witnesses) continue;
1109 // else fall through to process this guy's subclasses
1110 } else if (is_witness(sub) && !ignore_witness(sub)) {
1111 return sub;
1112 }
1113 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1114 // Fast path. (Partially disabled if VerifyDependencies.)
1115 ADD_SUBCLASS_CHAIN(sub);
1116 } else {
1117 // Worklist overflow. Do a recursive call. Should be rare.
1118 // The recursive call will have its own worklist, of course.
1119 // (Note that sub has already been tested, so that there is
1120 // no need for the recursive call to re-test. That's handy,
1121 // since the recursive call sees sub as the context_type.)
1122 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1123 Klass* witness = find_witness_anywhere(sub,
1124 participants_hide_witnesses,
1125 /*top_level_call=*/ false);
1126 if (witness != NULL) return witness;
1127 }
1128 }
1129 }
1130
1131 // No witness found. The dependency remains unbroken.
1132 return NULL;
1133 #undef ADD_SUBCLASS_CHAIN
1134 }
1135
1136
1137 bool Dependencies::is_concrete_klass(Klass* k) {
1138 if (k->is_abstract()) return false;
1139 // %%% We could treat classes which are concrete but
1140 // have not yet been instantiated as virtually abstract.
1141 // This would require a deoptimization barrier on first instantiation.
1142 //if (k->is_not_instantiated()) return false;
1143 return true;
1144 }
1145
1146 bool Dependencies::is_concrete_method(Method* m) {
1147 // Statics are irrelevant to virtual call sites.
1148 if (m->is_static()) return false;
1149
1150 // We could also return false if m does not yet appear to be
1151 // executed, if the VM version supports this distinction also.
1152 return !m->is_abstract() &&
1153 !InstanceKlass::cast(m->method_holder())->is_interface();
1154 // TODO: investigate whether default methods should be
1155 // considered as "concrete" in this situation. For now they
1156 // are not.
1157 }
1158
1159
1160 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1161 if (k->is_interface()) return NULL;
1162 if (k->has_finalizer()) return k;
1163 k = k->subklass();
1164 while (k != NULL) {
1165 Klass* result = find_finalizable_subclass(k);
1166 if (result != NULL) return result;
1167 k = k->next_sibling();
1168 }
1169 return NULL;
1170 }
1171
1172
1173 bool Dependencies::is_concrete_klass(DepValue k) {
1174 if (k.is_abstract_klass()) return false;
1175 // We could also return false if k does not yet appear to be
1176 // instantiated, if the VM version supports this distinction also.
1177 //if (k->is_not_instantiated()) return false;
1178 return true;
1179 }
1180
1181 bool Dependencies::is_concrete_method(DepValue m) {
1182 // Statics are irrelevant to virtual call sites.
1183 if (m.is_static_method()) return false;
1184
1185 // We could also return false if m does not yet appear to be
1186 // executed, if the VM version supports this distinction also.
1187 return !m.is_abstract_method();
1188 }
1189
1190
1191 bool Dependencies::has_finalizable_subclass(DepValue k) {
1192 return k.instance_klass_has_finalizable_subclass();
1193 }
1194
1195
1196 // Any use of the contents (bytecodes) of a method must be
1197 // marked by an "evol_method" dependency, if those contents
1198 // can change. (Note: A method is always dependent on itself.)
1199 Klass* Dependencies::check_evol_method(Method* m) {
1200 assert(must_be_in_vm(), "raw oops here");
1201 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1202 // Or is there a now a breakpoint?
1203 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1204 if (m->is_old()
1205 || m->number_of_breakpoints() > 0) {
1206 return m->method_holder();
1207 } else {
1208 return NULL;
1209 }
1210 }
1211
1212 // This is a strong assertion: It is that the given type
1213 // has no subtypes whatever. It is most useful for
1214 // optimizing checks on reflected types or on array types.
1215 // (Checks on types which are derived from real instances
1216 // can be optimized more strongly than this, because we
1217 // know that the checked type comes from a concrete type,
1218 // and therefore we can disregard abstract types.)
1219 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1220 assert(must_be_in_vm(), "raw oops here");
1221 assert_locked_or_safepoint(Compile_lock);
1222 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1223 Klass* sub = ctx->subklass();
1224 if (sub != NULL) {
1225 return sub;
1226 } else if (ctx->nof_implementors() != 0) {
1227 // if it is an interface, it must be unimplemented
1228 // (if it is not an interface, nof_implementors is always zero)
1229 Klass* impl = ctx->implementor();
1230 assert(impl != NULL, "must be set");
1231 return impl;
1232 } else {
1233 return NULL;
1234 }
1235 }
1236
1237 // Test the assertion that conck is the only concrete subtype* of ctxk.
1238 // The type conck itself is allowed to have have further concrete subtypes.
1239 // This allows the compiler to narrow occurrences of ctxk by conck,
1240 // when dealing with the types of actual instances.
1241 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1242 Klass* conck,
1243 KlassDepChange* changes) {
1244 ClassHierarchyWalker wf(conck);
1245 return wf.find_witness_subtype(ctxk, changes);
1246 }
1247
1248 // If a non-concrete class has no concrete subtypes, it is not (yet)
1249 // instantiatable. This can allow the compiler to make some paths go
1250 // dead, if they are gated by a test of the type.
1251 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1252 KlassDepChange* changes) {
1253 // Find any concrete subtype, with no participants:
1254 ClassHierarchyWalker wf;
1255 return wf.find_witness_subtype(ctxk, changes);
1256 }
1257
1258
1259 // If a concrete class has no concrete subtypes, it can always be
1260 // exactly typed. This allows the use of a cheaper type test.
1261 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1262 KlassDepChange* changes) {
1263 // Find any concrete subtype, with only the ctxk as participant:
1264 ClassHierarchyWalker wf(ctxk);
1265 return wf.find_witness_subtype(ctxk, changes);
1266 }
1267
1268
1269 // Find the unique concrete proper subtype of ctxk, or NULL if there
1270 // is more than one concrete proper subtype. If there are no concrete
1271 // proper subtypes, return ctxk itself, whether it is concrete or not.
1272 // The returned subtype is allowed to have have further concrete subtypes.
1273 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1274 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1275 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1276 wf.record_witnesses(1); // Record one other witness when walking.
1277 Klass* wit = wf.find_witness_subtype(ctxk);
1278 if (wit != NULL) return NULL; // Too many witnesses.
1279 Klass* conck = wf.participant(0);
1280 if (conck == NULL) {
1281 #ifndef PRODUCT
1282 // Make sure the dependency mechanism will pass this discovery:
1283 if (VerifyDependencies) {
1284 // Turn off dependency tracing while actually testing deps.
1285 FlagSetting fs(TraceDependencies, false);
1286 if (!Dependencies::is_concrete_klass(ctxk)) {
1287 guarantee(NULL ==
1288 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1289 "verify dep.");
1290 } else {
1291 guarantee(NULL ==
1292 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1293 "verify dep.");
1294 }
1295 }
1296 #endif //PRODUCT
1297 return ctxk; // Return ctxk as a flag for "no subtypes".
1298 } else {
1299 #ifndef PRODUCT
1300 // Make sure the dependency mechanism will pass this discovery:
1301 if (VerifyDependencies) {
1302 // Turn off dependency tracing while actually testing deps.
1303 FlagSetting fs(TraceDependencies, false);
1304 if (!Dependencies::is_concrete_klass(ctxk)) {
1305 guarantee(NULL == (void *)
1306 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1307 "verify dep.");
1308 }
1309 }
1310 #endif //PRODUCT
1311 return conck;
1312 }
1313 }
1314
1315 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1316 // except possibly for further subtypes of k[12] themselves.
1317 // The context type must be abstract. The types k1 and k2 are themselves
1318 // allowed to have further concrete subtypes.
1319 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1320 Klass* ctxk,
1321 Klass* k1,
1322 Klass* k2,
1323 KlassDepChange* changes) {
1324 ClassHierarchyWalker wf;
1325 wf.add_participant(k1);
1326 wf.add_participant(k2);
1327 return wf.find_witness_subtype(ctxk, changes);
1328 }
1329
1330 // Search ctxk for concrete implementations. If there are klen or fewer,
1331 // pack them into the given array and return the number.
1332 // Otherwise, return -1, meaning the given array would overflow.
1333 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1334 // In this search, if ctxk is concrete, it will be reported alone.
1335 // For any type CC reported, no proper subtypes of CC will be reported.
1336 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1337 int klen,
1338 Klass* karray[]) {
1339 ClassHierarchyWalker wf;
1340 wf.record_witnesses(klen);
1341 Klass* wit = wf.find_witness_subtype(ctxk);
1342 if (wit != NULL) return -1; // Too many witnesses.
1343 int num = wf.num_participants();
1344 assert(num <= klen, "oob");
1345 // Pack the result array with the good news.
1346 for (int i = 0; i < num; i++)
1347 karray[i] = wf.participant(i);
1348 #ifndef PRODUCT
1349 // Make sure the dependency mechanism will pass this discovery:
1350 if (VerifyDependencies) {
1351 // Turn off dependency tracing while actually testing deps.
1352 FlagSetting fs(TraceDependencies, false);
1353 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1354 case -1: // ctxk was itself concrete
1355 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1356 break;
1357 case 0:
1358 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1359 "verify dep.");
1360 break;
1361 case 1:
1362 guarantee(NULL == (void *)
1363 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1364 "verify dep.");
1365 break;
1366 case 2:
1367 guarantee(NULL == (void *)
1368 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1369 karray[0],
1370 karray[1]),
1371 "verify dep.");
1372 break;
1373 default:
1374 ShouldNotReachHere(); // klen > 2 yet supported
1375 }
1376 }
1377 #endif //PRODUCT
1378 return num;
1379 }
1380
1381 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1382 // Otherwise, return a class that contains an interfering method.
1383 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1384 KlassDepChange* changes) {
1385 // Here is a missing optimization: If uniqm->is_final(),
1386 // we don't really need to search beneath it for overrides.
1387 // This is probably not important, since we don't use dependencies
1388 // to track final methods. (They can't be "definalized".)
1389 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1390 return wf.find_witness_definer(ctxk, changes);
1391 }
1392
1393 // Find the set of all non-abstract methods under ctxk that match m.
1394 // (The method m must be defined or inherited in ctxk.)
1395 // Include m itself in the set, unless it is abstract.
1396 // If this set has exactly one element, return that element.
1397 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1398 ClassHierarchyWalker wf(m);
1399 assert(wf.check_method_context(ctxk, m), "proper context");
1400 wf.record_witnesses(1);
1401 Klass* wit = wf.find_witness_definer(ctxk);
1402 if (wit != NULL) return NULL; // Too many witnesses.
1403 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1404 if (Dependencies::is_concrete_method(m)) {
1405 if (fm == NULL) {
1406 // It turns out that m was always the only implementation.
1407 fm = m;
1408 } else if (fm != m) {
1409 // Two conflicting implementations after all.
1410 // (This can happen if m is inherited into ctxk and fm overrides it.)
1411 return NULL;
1412 }
1413 }
1414 #ifndef PRODUCT
1415 // Make sure the dependency mechanism will pass this discovery:
1416 if (VerifyDependencies && fm != NULL) {
1417 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1418 "verify dep.");
1419 }
1420 #endif //PRODUCT
1421 return fm;
1422 }
1423
1424 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1425 Method* m1,
1426 Method* m2,
1427 KlassDepChange* changes) {
1428 ClassHierarchyWalker wf(m1);
1429 wf.add_participant(m1->method_holder());
1430 wf.add_participant(m2->method_holder());
1431 return wf.find_witness_definer(ctxk, changes);
1432 }
1433
1434 // Find the set of all non-abstract methods under ctxk that match m[0].
1435 // (The method m[0] must be defined or inherited in ctxk.)
1436 // Include m itself in the set, unless it is abstract.
1437 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1438 // (The length may be zero if no concrete methods are found anywhere.)
1439 // If there are too many concrete methods to fit in marray, return -1.
1440 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1441 int mlen,
1442 Method* marray[]) {
1443 Method* m0 = marray[0];
1444 ClassHierarchyWalker wf(m0);
1445 assert(wf.check_method_context(ctxk, m0), "proper context");
1446 wf.record_witnesses(mlen);
1447 bool participants_hide_witnesses = true;
1448 Klass* wit = wf.find_witness_definer(ctxk);
1449 if (wit != NULL) return -1; // Too many witnesses.
1450 int num = wf.num_participants();
1451 assert(num <= mlen, "oob");
1452 // Keep track of whether m is also part of the result set.
1453 int mfill = 0;
1454 assert(marray[mfill] == m0, "sanity");
1455 if (Dependencies::is_concrete_method(m0))
1456 mfill++; // keep m0 as marray[0], the first result
1457 for (int i = 0; i < num; i++) {
1458 Method* fm = wf.found_method(i);
1459 if (fm == m0) continue; // Already put this guy in the list.
1460 if (mfill == mlen) {
1461 return -1; // Oops. Too many methods after all!
1462 }
1463 marray[mfill++] = fm;
1464 }
1465 #ifndef PRODUCT
1466 // Make sure the dependency mechanism will pass this discovery:
1467 if (VerifyDependencies) {
1468 // Turn off dependency tracing while actually testing deps.
1469 FlagSetting fs(TraceDependencies, false);
1470 switch (mfill) {
1471 case 1:
1472 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1473 "verify dep.");
1474 break;
1475 case 2:
1476 guarantee(NULL == (void *)
1477 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1478 "verify dep.");
1479 break;
1480 default:
1481 ShouldNotReachHere(); // mlen > 2 yet supported
1482 }
1483 }
1484 #endif //PRODUCT
1485 return mfill;
1486 }
1487
1488
1489 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1490 Klass* search_at = ctxk;
1491 if (changes != NULL)
1492 search_at = changes->new_type(); // just look at the new bit
1493 return find_finalizable_subclass(search_at);
1494 }
1495
1496
1497 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1498 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1499 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1500 if (changes == NULL) {
1501 // Validate all CallSites
1502 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1503 return call_site->klass(); // assertion failed
1504 } else {
1505 // Validate the given CallSite
1506 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1507 assert(method_handle != changes->method_handle(), "must be");
1508 return call_site->klass(); // assertion failed
1509 }
1510 }
1511 return NULL; // assertion still valid
1512 }
1513
1514
1515 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1516 if (witness != NULL) {
1517 if (TraceDependencies) {
1518 print_dependency(witness, /*verbose=*/ true);
1519 }
1520 // The following is a no-op unless logging is enabled:
1521 log_dependency(witness);
1522 }
1523 }
1524
1525
1526 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1527 assert_locked_or_safepoint(Compile_lock);
1528 Dependencies::check_valid_dependency_type(type());
1529
1530 Klass* witness = NULL;
1531 switch (type()) {
1532 case evol_method:
1533 witness = check_evol_method(method_argument(0));
1534 break;
1535 case leaf_type:
1536 witness = check_leaf_type(context_type());
1537 break;
1538 case abstract_with_unique_concrete_subtype:
1539 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1540 break;
1541 case abstract_with_no_concrete_subtype:
1542 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1543 break;
1544 case concrete_with_no_concrete_subtype:
1545 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1546 break;
1547 case unique_concrete_method:
1548 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1549 break;
1550 case abstract_with_exclusive_concrete_subtypes_2:
1551 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1552 break;
1553 case exclusive_concrete_methods_2:
1554 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1555 break;
1556 case no_finalizable_subclasses:
1557 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1558 break;
1559 default:
1560 witness = NULL;
1561 break;
1562 }
1563 trace_and_log_witness(witness);
1564 return witness;
1565 }
1566
1567
1568 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1569 assert_locked_or_safepoint(Compile_lock);
1570 Dependencies::check_valid_dependency_type(type());
1571
1572 Klass* witness = NULL;
1573 switch (type()) {
1574 case call_site_target_value:
1575 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1576 break;
1577 default:
1578 witness = NULL;
1579 break;
1580 }
1581 trace_and_log_witness(witness);
1582 return witness;
1583 }
1584
1585
1586 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1587 // Handle klass dependency
1588 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1589 return check_klass_dependency(changes.as_klass_change());
1590
1591 // Handle CallSite dependency
1592 if (changes.is_call_site_change())
1593 return check_call_site_dependency(changes.as_call_site_change());
1594
1595 // irrelevant dependency; skip it
1596 return NULL;
1597 }
1598
1599
1600 void DepChange::print() {
1601 int nsup = 0, nint = 0;
1602 for (ContextStream str(*this); str.next(); ) {
1603 Klass* k = str.klass();
1604 switch (str.change_type()) {
1605 case Change_new_type:
1606 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1607 break;
1608 case Change_new_sub:
1609 if (!WizardMode) {
1610 ++nsup;
1611 } else {
1612 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1613 }
1614 break;
1615 case Change_new_impl:
1616 if (!WizardMode) {
1617 ++nint;
1618 } else {
1619 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1620 }
1621 break;
1622 }
1623 }
1624 if (nsup + nint != 0) {
1625 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1626 }
1627 }
1628
1629 void DepChange::ContextStream::start() {
1630 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1631 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1632 _klass = new_type;
1633 _ti_base = NULL;
1634 _ti_index = 0;
1635 _ti_limit = 0;
1636 }
1637
1638 bool DepChange::ContextStream::next() {
1639 switch (_change_type) {
1640 case Start_Klass: // initial state; _klass is the new type
1641 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1642 _ti_index = 0;
1643 _change_type = Change_new_type;
1644 return true;
1645 case Change_new_type:
1646 // fall through:
1647 _change_type = Change_new_sub;
1648 case Change_new_sub:
1649 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1650 {
1651 _klass = InstanceKlass::cast(_klass)->super();
1652 if (_klass != NULL) {
1653 return true;
1654 }
1655 }
1656 // else set up _ti_limit and fall through:
1657 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1658 _change_type = Change_new_impl;
1659 case Change_new_impl:
1660 if (_ti_index < _ti_limit) {
1661 _klass = _ti_base->at(_ti_index++);
1662 return true;
1663 }
1664 // fall through:
1665 _change_type = NO_CHANGE; // iterator is exhausted
1666 case NO_CHANGE:
1667 break;
1668 default:
1669 ShouldNotReachHere();
1670 }
1671 return false;
1672 }
1673
1674 void KlassDepChange::initialize() {
1675 // entire transaction must be under this lock:
1676 assert_lock_strong(Compile_lock);
1677
1678 // Mark all dependee and all its superclasses
1679 // Mark transitive interfaces
1680 for (ContextStream str(*this); str.next(); ) {
1681 Klass* d = str.klass();
1682 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1683 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1684 }
1685 }
1686
1687 KlassDepChange::~KlassDepChange() {
1688 // Unmark all dependee and all its superclasses
1689 // Unmark transitive interfaces
1690 for (ContextStream str(*this); str.next(); ) {
1691 Klass* d = str.klass();
1692 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1693 }
1694 }
1695
1696 bool KlassDepChange::involves_context(Klass* k) {
1697 if (k == NULL || !k->oop_is_instance()) {
1698 return false;
1699 }
1700 InstanceKlass* ik = InstanceKlass::cast(k);
1701 bool is_contained = ik->is_marked_dependent();
1702 assert(is_contained == new_type()->is_subtype_of(k),
1703 "correct marking of potential context types");
1704 return is_contained;
1705 }
1706
1707 #ifndef PRODUCT
1708 void Dependencies::print_statistics() {
1709 if (deps_find_witness_print != 0) {
1710 // Call one final time, to flush out the data.
1711 deps_find_witness_print = -1;
1712 count_find_witness_calls();
1713 }
1714 }
1715 #endif