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