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 return o;
659 }
660
661 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
662 return (_code != NULL)
663 ? _code->oop_at(i)
664 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
665 }
666
667 Metadata* Dependencies::DepStream::argument(int i) {
668 Metadata* result = recorded_metadata_at(argument_index(i));
669
670 if (result == NULL) { // Explicit context argument can be compressed
671 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
672 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
673 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
674 }
675 }
676
677 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
678 return result;
679 }
680
681 /**
682 * Returns a unique identifier for each dependency argument.
683 */
684 uintptr_t Dependencies::DepStream::get_identifier(int i) {
685 if (has_oop_argument()) {
686 return (uintptr_t)(oopDesc*)argument_oop(i);
687 } else {
688 return (uintptr_t)argument(i);
689 }
690 }
691
692 oop Dependencies::DepStream::argument_oop(int i) {
693 oop result = recorded_oop_at(argument_index(i));
694 assert(result == NULL || result->is_oop(), "must be");
695 return result;
696 }
697
698 Klass* Dependencies::DepStream::context_type() {
699 assert(must_be_in_vm(), "raw oops here");
700
701 // Most dependencies have an explicit context type argument.
702 {
703 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
704 if (ctxkj >= 0) {
705 Metadata* k = argument(ctxkj);
706 assert(k != NULL && k->is_klass(), "type check");
707 return (Klass*)k;
708 }
709 }
710
711 // Some dependencies are using the klass of the first object
712 // argument as implicit context type (e.g. call_site_target_value).
713 {
714 int ctxkj = dep_implicit_context_arg(type());
715 if (ctxkj >= 0) {
716 Klass* k = argument_oop(ctxkj)->klass();
717 assert(k != NULL && k->is_klass(), "type check");
718 return (Klass*) k;
719 }
720 }
721
722 // And some dependencies don't have a context type at all,
723 // e.g. evol_method.
724 return NULL;
725 }
726
727 // ----------------- DependencySignature --------------------------------------
728 bool DependencySignature::equals(const DependencySignature& sig) const {
729 if (type() != sig.type()) {
730 return false;
731 }
732
733 if (args_count() != sig.args_count()) {
734 return false;
735 }
736
737 for (int i = 0; i < sig.args_count(); i++) {
738 if (arg(i) != sig.arg(i)) {
739 return false;
740 }
741 }
742 return true;
743 }
744
745
746 // ----------------- DependencySignatureBuffer --------------------------------------
747 DependencySignatureBuffer::DependencySignatureBuffer() {
748 _signatures = NEW_RESOURCE_ARRAY(GrowableArray<DependencySignature*>*, Dependencies::TYPE_LIMIT);
749 memset(_signatures, 0, sizeof(DependencySignature*) * Dependencies::TYPE_LIMIT);
750 }
751
752 /* Check if arguments are identical. Two dependency signatures are considered
753 * identical, if the type as well as all argument identifiers are identical.
754 * If the dependency has not already been checked, the dependency signature is
755 * added to the checked dependencies of the same type. The function returns
756 * false, which causes the dependency to be checked in the caller.
757 */
758 bool DependencySignatureBuffer::add_if_missing(const DependencySignature& sig) {
759 const int index = sig.type();
760 GrowableArray<DependencySignature*>* buffer = _signatures[index];
761 if (buffer == NULL) {
762 buffer = new GrowableArray<DependencySignature*>();
763 _signatures[index] = buffer;
764 }
765
766 // Check if we have already checked the dependency
767 for (int i = 0; i < buffer->length(); i++) {
768 DependencySignature* checked_signature = buffer->at(i);
769 if (checked_signature->equals(sig)) {
770 return true;
771 }
772 }
773 buffer->append((DependencySignature*)&sig);
774 return false;
775 }
776
777
778 /// Checking dependencies:
779
780 // This hierarchy walker inspects subtypes of a given type,
781 // trying to find a "bad" class which breaks a dependency.
782 // Such a class is called a "witness" to the broken dependency.
783 // While searching around, we ignore "participants", which
784 // are already known to the dependency.
785 class ClassHierarchyWalker {
786 public:
787 enum { PARTICIPANT_LIMIT = 3 };
788
789 private:
790 // optional method descriptor to check for:
791 Symbol* _name;
792 Symbol* _signature;
793
794 // special classes which are not allowed to be witnesses:
795 Klass* _participants[PARTICIPANT_LIMIT+1];
796 int _num_participants;
797
798 // cache of method lookups
799 Method* _found_methods[PARTICIPANT_LIMIT+1];
800
801 // if non-zero, tells how many witnesses to convert to participants
802 int _record_witnesses;
803
804 void initialize(Klass* participant) {
805 _record_witnesses = 0;
806 _participants[0] = participant;
807 _found_methods[0] = NULL;
808 _num_participants = 0;
809 if (participant != NULL) {
810 // Terminating NULL.
811 _participants[1] = NULL;
812 _found_methods[1] = NULL;
813 _num_participants = 1;
814 }
815 }
816
817 void initialize_from_method(Method* m) {
818 assert(m != NULL && m->is_method(), "sanity");
819 _name = m->name();
820 _signature = m->signature();
821 }
822
823 public:
824 // The walker is initialized to recognize certain methods and/or types
825 // as friendly participants.
826 ClassHierarchyWalker(Klass* participant, Method* m) {
827 initialize_from_method(m);
828 initialize(participant);
829 }
830 ClassHierarchyWalker(Method* m) {
831 initialize_from_method(m);
832 initialize(NULL);
833 }
834 ClassHierarchyWalker(Klass* participant = NULL) {
835 _name = NULL;
836 _signature = NULL;
837 initialize(participant);
838 }
839
840 // This is common code for two searches: One for concrete subtypes,
841 // the other for concrete method implementations and overrides.
842 bool doing_subtype_search() {
843 return _name == NULL;
844 }
845
846 int num_participants() { return _num_participants; }
847 Klass* participant(int n) {
848 assert((uint)n <= (uint)_num_participants, "oob");
849 return _participants[n];
850 }
851
852 // Note: If n==num_participants, returns NULL.
853 Method* found_method(int n) {
854 assert((uint)n <= (uint)_num_participants, "oob");
855 Method* fm = _found_methods[n];
856 assert(n == _num_participants || fm != NULL, "proper usage");
857 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
858 return fm;
859 }
860
861 #ifdef ASSERT
862 // Assert that m is inherited into ctxk, without intervening overrides.
863 // (May return true even if this is not true, in corner cases where we punt.)
864 bool check_method_context(Klass* ctxk, Method* m) {
865 if (m->method_holder() == ctxk)
866 return true; // Quick win.
867 if (m->is_private())
868 return false; // Quick lose. Should not happen.
869 if (!(m->is_public() || m->is_protected()))
870 // The override story is complex when packages get involved.
871 return true; // Must punt the assertion to true.
872 Klass* k = ctxk;
873 Method* lm = k->lookup_method(m->name(), m->signature());
874 if (lm == NULL && k->oop_is_instance()) {
875 // It might be an interface method
876 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
877 m->signature());
878 }
879 if (lm == m)
880 // Method m is inherited into ctxk.
881 return true;
882 if (lm != NULL) {
883 if (!(lm->is_public() || lm->is_protected())) {
884 // Method is [package-]private, so the override story is complex.
885 return true; // Must punt the assertion to true.
886 }
887 if (lm->is_static()) {
888 // Static methods don't override non-static so punt
889 return true;
890 }
891 if ( !Dependencies::is_concrete_method(lm)
892 && !Dependencies::is_concrete_method(m)
893 && lm->method_holder()->is_subtype_of(m->method_holder()))
894 // Method m is overridden by lm, but both are non-concrete.
895 return true;
896 }
897 ResourceMark rm;
898 tty->print_cr("Dependency method not found in the associated context:");
899 tty->print_cr(" context = %s", ctxk->external_name());
900 tty->print( " method = "); m->print_short_name(tty); tty->cr();
901 if (lm != NULL) {
902 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
903 }
904 return false;
905 }
906 #endif
907
908 void add_participant(Klass* participant) {
909 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
910 int np = _num_participants++;
911 _participants[np] = participant;
912 _participants[np+1] = NULL;
913 _found_methods[np+1] = NULL;
914 }
915
916 void record_witnesses(int add) {
917 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
918 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
919 _record_witnesses = add;
920 }
921
922 bool is_witness(Klass* k) {
923 if (doing_subtype_search()) {
924 return Dependencies::is_concrete_klass(k);
925 } else {
926 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
927 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
928 _found_methods[_num_participants] = m;
929 // Note: If add_participant(k) is called,
930 // the method m will already be memoized for it.
931 return true;
932 }
933 }
934
935 bool is_participant(Klass* k) {
936 if (k == _participants[0]) {
937 return true;
938 } else if (_num_participants <= 1) {
939 return false;
940 } else {
941 return in_list(k, &_participants[1]);
942 }
943 }
944 bool ignore_witness(Klass* witness) {
945 if (_record_witnesses == 0) {
946 return false;
947 } else {
948 --_record_witnesses;
949 add_participant(witness);
950 return true;
951 }
952 }
953 static bool in_list(Klass* x, Klass** list) {
954 for (int i = 0; ; i++) {
955 Klass* y = list[i];
956 if (y == NULL) break;
957 if (y == x) return true;
958 }
959 return false; // not in list
960 }
961
962 private:
963 // the actual search method:
964 Klass* find_witness_anywhere(Klass* context_type,
965 bool participants_hide_witnesses,
966 bool top_level_call = true);
967 // the spot-checking version:
968 Klass* find_witness_in(KlassDepChange& changes,
969 Klass* context_type,
970 bool participants_hide_witnesses);
971 public:
972 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
973 assert(doing_subtype_search(), "must set up a subtype search");
974 // When looking for unexpected concrete types,
975 // do not look beneath expected ones.
976 const bool participants_hide_witnesses = true;
977 // CX > CC > C' is OK, even if C' is new.
978 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
979 if (changes != NULL) {
980 return find_witness_in(*changes, context_type, participants_hide_witnesses);
981 } else {
982 return find_witness_anywhere(context_type, participants_hide_witnesses);
983 }
984 }
985 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
986 assert(!doing_subtype_search(), "must set up a method definer search");
987 // When looking for unexpected concrete methods,
988 // look beneath expected ones, to see if there are overrides.
989 const bool participants_hide_witnesses = true;
990 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
991 if (changes != NULL) {
992 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
993 } else {
994 return find_witness_anywhere(context_type, !participants_hide_witnesses);
995 }
996 }
997 };
998
999 #ifndef PRODUCT
1000 static int deps_find_witness_calls = 0;
1001 static int deps_find_witness_steps = 0;
1002 static int deps_find_witness_recursions = 0;
1003 static int deps_find_witness_singles = 0;
1004 static int deps_find_witness_print = 0; // set to -1 to force a final print
1005 static bool count_find_witness_calls() {
1006 if (TraceDependencies || LogCompilation) {
1007 int pcount = deps_find_witness_print + 1;
1008 bool final_stats = (pcount == 0);
1009 bool initial_call = (pcount == 1);
1010 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
1011 if (pcount < 0) pcount = 1; // crude overflow protection
1012 deps_find_witness_print = pcount;
1013 if (VerifyDependencies && initial_call) {
1014 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
1015 }
1016 if (occasional_print || final_stats) {
1017 // Every now and then dump a little info about dependency searching.
1018 if (xtty != NULL) {
1019 ttyLocker ttyl;
1020 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
1021 deps_find_witness_calls,
1022 deps_find_witness_steps,
1023 deps_find_witness_recursions,
1024 deps_find_witness_singles);
1025 }
1026 if (final_stats || (TraceDependencies && WizardMode)) {
1027 ttyLocker ttyl;
1028 tty->print_cr("Dependency check (find_witness) "
1029 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
1030 deps_find_witness_calls,
1031 deps_find_witness_steps,
1032 (double)deps_find_witness_steps / deps_find_witness_calls,
1033 deps_find_witness_recursions,
1034 deps_find_witness_singles);
1035 }
1036 }
1037 return true;
1038 }
1039 return false;
1040 }
1041 #else
1042 #define count_find_witness_calls() (0)
1043 #endif //PRODUCT
1044
1045
1046 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1047 Klass* context_type,
1048 bool participants_hide_witnesses) {
1049 assert(changes.involves_context(context_type), "irrelevant dependency");
1050 Klass* new_type = changes.new_type();
1051
1052 (void)count_find_witness_calls();
1053 NOT_PRODUCT(deps_find_witness_singles++);
1054
1055 // Current thread must be in VM (not native mode, as in CI):
1056 assert(must_be_in_vm(), "raw oops here");
1057 // Must not move the class hierarchy during this check:
1058 assert_locked_or_safepoint(Compile_lock);
1059
1060 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1061 if (nof_impls > 1) {
1062 // Avoid this case: *I.m > { A.m, C }; B.m > C
1063 // %%% Until this is fixed more systematically, bail out.
1064 // See corresponding comment in find_witness_anywhere.
1065 return context_type;
1066 }
1067
1068 assert(!is_participant(new_type), "only old classes are participants");
1069 if (participants_hide_witnesses) {
1070 // If the new type is a subtype of a participant, we are done.
1071 for (int i = 0; i < num_participants(); i++) {
1072 Klass* part = participant(i);
1073 if (part == NULL) continue;
1074 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1075 "correct marking of participants, b/c new_type is unique");
1076 if (changes.involves_context(part)) {
1077 // new guy is protected from this check by previous participant
1078 return NULL;
1079 }
1080 }
1081 }
1082
1083 if (is_witness(new_type) &&
1084 !ignore_witness(new_type)) {
1085 return new_type;
1086 }
1087
1088 return NULL;
1089 }
1090
1091
1092 // Walk hierarchy under a context type, looking for unexpected types.
1093 // Do not report participant types, and recursively walk beneath
1094 // them only if participants_hide_witnesses is false.
1095 // If top_level_call is false, skip testing the context type,
1096 // because the caller has already considered it.
1097 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1098 bool participants_hide_witnesses,
1099 bool top_level_call) {
1100 // Current thread must be in VM (not native mode, as in CI):
1101 assert(must_be_in_vm(), "raw oops here");
1102 // Must not move the class hierarchy during this check:
1103 assert_locked_or_safepoint(Compile_lock);
1104
1105 bool do_counts = count_find_witness_calls();
1106
1107 // Check the root of the sub-hierarchy first.
1108 if (top_level_call) {
1109 if (do_counts) {
1110 NOT_PRODUCT(deps_find_witness_calls++);
1111 NOT_PRODUCT(deps_find_witness_steps++);
1112 }
1113 if (is_participant(context_type)) {
1114 if (participants_hide_witnesses) return NULL;
1115 // else fall through to search loop...
1116 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1117 // The context is an abstract class or interface, to start with.
1118 return context_type;
1119 }
1120 }
1121
1122 // Now we must check each implementor and each subclass.
1123 // Use a short worklist to avoid blowing the stack.
1124 // Each worklist entry is a *chain* of subklass siblings to process.
1125 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1126 Klass* chains[CHAINMAX];
1127 int chaini = 0; // index into worklist
1128 Klass* chain; // scratch variable
1129 #define ADD_SUBCLASS_CHAIN(k) { \
1130 assert(chaini < CHAINMAX, "oob"); \
1131 chain = InstanceKlass::cast(k)->subklass(); \
1132 if (chain != NULL) chains[chaini++] = chain; }
1133
1134 // Look for non-abstract subclasses.
1135 // (Note: Interfaces do not have subclasses.)
1136 ADD_SUBCLASS_CHAIN(context_type);
1137
1138 // If it is an interface, search its direct implementors.
1139 // (Their subclasses are additional indirect implementors.
1140 // See InstanceKlass::add_implementor.)
1141 // (Note: nof_implementors is always zero for non-interfaces.)
1142 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1143 if (nof_impls > 1) {
1144 // Avoid this case: *I.m > { A.m, C }; B.m > C
1145 // Here, I.m has 2 concrete implementations, but m appears unique
1146 // as A.m, because the search misses B.m when checking C.
1147 // The inherited method B.m was getting missed by the walker
1148 // when interface 'I' was the starting point.
1149 // %%% Until this is fixed more systematically, bail out.
1150 // (Old CHA had the same limitation.)
1151 return context_type;
1152 }
1153 if (nof_impls > 0) {
1154 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1155 assert(impl != NULL, "just checking");
1156 // If impl is the same as the context_type, then more than one
1157 // implementor has seen. No exact info in this case.
1158 if (impl == context_type) {
1159 return context_type; // report an inexact witness to this sad affair
1160 }
1161 if (do_counts)
1162 { NOT_PRODUCT(deps_find_witness_steps++); }
1163 if (is_participant(impl)) {
1164 if (!participants_hide_witnesses) {
1165 ADD_SUBCLASS_CHAIN(impl);
1166 }
1167 } else if (is_witness(impl) && !ignore_witness(impl)) {
1168 return impl;
1169 } else {
1170 ADD_SUBCLASS_CHAIN(impl);
1171 }
1172 }
1173
1174 // Recursively process each non-trivial sibling chain.
1175 while (chaini > 0) {
1176 Klass* chain = chains[--chaini];
1177 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1178 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1179 if (is_participant(sub)) {
1180 if (participants_hide_witnesses) continue;
1181 // else fall through to process this guy's subclasses
1182 } else if (is_witness(sub) && !ignore_witness(sub)) {
1183 return sub;
1184 }
1185 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1186 // Fast path. (Partially disabled if VerifyDependencies.)
1187 ADD_SUBCLASS_CHAIN(sub);
1188 } else {
1189 // Worklist overflow. Do a recursive call. Should be rare.
1190 // The recursive call will have its own worklist, of course.
1191 // (Note that sub has already been tested, so that there is
1192 // no need for the recursive call to re-test. That's handy,
1193 // since the recursive call sees sub as the context_type.)
1194 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1195 Klass* witness = find_witness_anywhere(sub,
1196 participants_hide_witnesses,
1197 /*top_level_call=*/ false);
1198 if (witness != NULL) return witness;
1199 }
1200 }
1201 }
1202
1203 // No witness found. The dependency remains unbroken.
1204 return NULL;
1205 #undef ADD_SUBCLASS_CHAIN
1206 }
1207
1208
1209 bool Dependencies::is_concrete_klass(Klass* k) {
1210 if (k->is_abstract()) return false;
1211 // %%% We could treat classes which are concrete but
1212 // have not yet been instantiated as virtually abstract.
1213 // This would require a deoptimization barrier on first instantiation.
1214 //if (k->is_not_instantiated()) return false;
1215 return true;
1216 }
1217
1218 bool Dependencies::is_concrete_method(Method* m) {
1219 // Statics are irrelevant to virtual call sites.
1220 if (m->is_static()) return false;
1221
1222 // We could also return false if m does not yet appear to be
1223 // executed, if the VM version supports this distinction also.
1224 // Default methods are considered "concrete" as well.
1225 return !m->is_abstract() &&
1226 !m->is_overpass(); // error functions aren't concrete
1227 }
1228
1229
1230 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1231 if (k->is_interface()) return NULL;
1232 if (k->has_finalizer()) return k;
1233 k = k->subklass();
1234 while (k != NULL) {
1235 Klass* result = find_finalizable_subclass(k);
1236 if (result != NULL) return result;
1237 k = k->next_sibling();
1238 }
1239 return NULL;
1240 }
1241
1242
1243 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1244 if (k->is_abstract()) return false;
1245 // We could also return false if k does not yet appear to be
1246 // instantiated, if the VM version supports this distinction also.
1247 //if (k->is_not_instantiated()) return false;
1248 return true;
1249 }
1250
1251 bool Dependencies::is_concrete_method(ciMethod* m) {
1252 // Statics are irrelevant to virtual call sites.
1253 if (m->is_static()) return false;
1254
1255 // We could also return false if m does not yet appear to be
1256 // executed, if the VM version supports this distinction also.
1257 return !m->is_abstract();
1258 }
1259
1260
1261 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1262 return k->has_finalizable_subclass();
1263 }
1264
1265
1266 // Any use of the contents (bytecodes) of a method must be
1267 // marked by an "evol_method" dependency, if those contents
1268 // can change. (Note: A method is always dependent on itself.)
1269 Klass* Dependencies::check_evol_method(Method* m) {
1270 assert(must_be_in_vm(), "raw oops here");
1271 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1272 // Or is there a now a breakpoint?
1273 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1274 if (m->is_old()
1275 || m->number_of_breakpoints() > 0) {
1276 return m->method_holder();
1277 } else {
1278 return NULL;
1279 }
1280 }
1281
1282 // This is a strong assertion: It is that the given type
1283 // has no subtypes whatever. It is most useful for
1284 // optimizing checks on reflected types or on array types.
1285 // (Checks on types which are derived from real instances
1286 // can be optimized more strongly than this, because we
1287 // know that the checked type comes from a concrete type,
1288 // and therefore we can disregard abstract types.)
1289 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1290 assert(must_be_in_vm(), "raw oops here");
1291 assert_locked_or_safepoint(Compile_lock);
1292 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1293 Klass* sub = ctx->subklass();
1294 if (sub != NULL) {
1295 return sub;
1296 } else if (ctx->nof_implementors() != 0) {
1297 // if it is an interface, it must be unimplemented
1298 // (if it is not an interface, nof_implementors is always zero)
1299 Klass* impl = ctx->implementor();
1300 assert(impl != NULL, "must be set");
1301 return impl;
1302 } else {
1303 return NULL;
1304 }
1305 }
1306
1307 // Test the assertion that conck is the only concrete subtype* of ctxk.
1308 // The type conck itself is allowed to have have further concrete subtypes.
1309 // This allows the compiler to narrow occurrences of ctxk by conck,
1310 // when dealing with the types of actual instances.
1311 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1312 Klass* conck,
1313 KlassDepChange* changes) {
1314 ClassHierarchyWalker wf(conck);
1315 return wf.find_witness_subtype(ctxk, changes);
1316 }
1317
1318 // If a non-concrete class has no concrete subtypes, it is not (yet)
1319 // instantiatable. This can allow the compiler to make some paths go
1320 // dead, if they are gated by a test of the type.
1321 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1322 KlassDepChange* changes) {
1323 // Find any concrete subtype, with no participants:
1324 ClassHierarchyWalker wf;
1325 return wf.find_witness_subtype(ctxk, changes);
1326 }
1327
1328
1329 // If a concrete class has no concrete subtypes, it can always be
1330 // exactly typed. This allows the use of a cheaper type test.
1331 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1332 KlassDepChange* changes) {
1333 // Find any concrete subtype, with only the ctxk as participant:
1334 ClassHierarchyWalker wf(ctxk);
1335 return wf.find_witness_subtype(ctxk, changes);
1336 }
1337
1338
1339 // Find the unique concrete proper subtype of ctxk, or NULL if there
1340 // is more than one concrete proper subtype. If there are no concrete
1341 // proper subtypes, return ctxk itself, whether it is concrete or not.
1342 // The returned subtype is allowed to have have further concrete subtypes.
1343 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1344 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1345 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1346 wf.record_witnesses(1); // Record one other witness when walking.
1347 Klass* wit = wf.find_witness_subtype(ctxk);
1348 if (wit != NULL) return NULL; // Too many witnesses.
1349 Klass* conck = wf.participant(0);
1350 if (conck == NULL) {
1351 #ifndef PRODUCT
1352 // Make sure the dependency mechanism will pass this discovery:
1353 if (VerifyDependencies) {
1354 // Turn off dependency tracing while actually testing deps.
1355 FlagSetting fs(TraceDependencies, false);
1356 if (!Dependencies::is_concrete_klass(ctxk)) {
1357 guarantee(NULL ==
1358 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1359 "verify dep.");
1360 } else {
1361 guarantee(NULL ==
1362 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1363 "verify dep.");
1364 }
1365 }
1366 #endif //PRODUCT
1367 return ctxk; // Return ctxk as a flag for "no subtypes".
1368 } else {
1369 #ifndef PRODUCT
1370 // Make sure the dependency mechanism will pass this discovery:
1371 if (VerifyDependencies) {
1372 // Turn off dependency tracing while actually testing deps.
1373 FlagSetting fs(TraceDependencies, false);
1374 if (!Dependencies::is_concrete_klass(ctxk)) {
1375 guarantee(NULL == (void *)
1376 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1377 "verify dep.");
1378 }
1379 }
1380 #endif //PRODUCT
1381 return conck;
1382 }
1383 }
1384
1385 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1386 // except possibly for further subtypes of k[12] themselves.
1387 // The context type must be abstract. The types k1 and k2 are themselves
1388 // allowed to have further concrete subtypes.
1389 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1390 Klass* ctxk,
1391 Klass* k1,
1392 Klass* k2,
1393 KlassDepChange* changes) {
1394 ClassHierarchyWalker wf;
1395 wf.add_participant(k1);
1396 wf.add_participant(k2);
1397 return wf.find_witness_subtype(ctxk, changes);
1398 }
1399
1400 // Search ctxk for concrete implementations. If there are klen or fewer,
1401 // pack them into the given array and return the number.
1402 // Otherwise, return -1, meaning the given array would overflow.
1403 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1404 // In this search, if ctxk is concrete, it will be reported alone.
1405 // For any type CC reported, no proper subtypes of CC will be reported.
1406 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1407 int klen,
1408 Klass* karray[]) {
1409 ClassHierarchyWalker wf;
1410 wf.record_witnesses(klen);
1411 Klass* wit = wf.find_witness_subtype(ctxk);
1412 if (wit != NULL) return -1; // Too many witnesses.
1413 int num = wf.num_participants();
1414 assert(num <= klen, "oob");
1415 // Pack the result array with the good news.
1416 for (int i = 0; i < num; i++)
1417 karray[i] = wf.participant(i);
1418 #ifndef PRODUCT
1419 // Make sure the dependency mechanism will pass this discovery:
1420 if (VerifyDependencies) {
1421 // Turn off dependency tracing while actually testing deps.
1422 FlagSetting fs(TraceDependencies, false);
1423 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1424 case -1: // ctxk was itself concrete
1425 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1426 break;
1427 case 0:
1428 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1429 "verify dep.");
1430 break;
1431 case 1:
1432 guarantee(NULL == (void *)
1433 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1434 "verify dep.");
1435 break;
1436 case 2:
1437 guarantee(NULL == (void *)
1438 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1439 karray[0],
1440 karray[1]),
1441 "verify dep.");
1442 break;
1443 default:
1444 ShouldNotReachHere(); // klen > 2 yet supported
1445 }
1446 }
1447 #endif //PRODUCT
1448 return num;
1449 }
1450
1451 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1452 // Otherwise, return a class that contains an interfering method.
1453 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1454 KlassDepChange* changes) {
1455 // Here is a missing optimization: If uniqm->is_final(),
1456 // we don't really need to search beneath it for overrides.
1457 // This is probably not important, since we don't use dependencies
1458 // to track final methods. (They can't be "definalized".)
1459 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1460 return wf.find_witness_definer(ctxk, changes);
1461 }
1462
1463 // Find the set of all non-abstract methods under ctxk that match m.
1464 // (The method m must be defined or inherited in ctxk.)
1465 // Include m itself in the set, unless it is abstract.
1466 // If this set has exactly one element, return that element.
1467 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1468 ClassHierarchyWalker wf(m);
1469 assert(wf.check_method_context(ctxk, m), "proper context");
1470 wf.record_witnesses(1);
1471 Klass* wit = wf.find_witness_definer(ctxk);
1472 if (wit != NULL) return NULL; // Too many witnesses.
1473 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1474 if (Dependencies::is_concrete_method(m)) {
1475 if (fm == NULL) {
1476 // It turns out that m was always the only implementation.
1477 fm = m;
1478 } else if (fm != m) {
1479 // Two conflicting implementations after all.
1480 // (This can happen if m is inherited into ctxk and fm overrides it.)
1481 return NULL;
1482 }
1483 }
1484 #ifndef PRODUCT
1485 // Make sure the dependency mechanism will pass this discovery:
1486 if (VerifyDependencies && fm != NULL) {
1487 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1488 "verify dep.");
1489 }
1490 #endif //PRODUCT
1491 return fm;
1492 }
1493
1494 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1495 Method* m1,
1496 Method* m2,
1497 KlassDepChange* changes) {
1498 ClassHierarchyWalker wf(m1);
1499 wf.add_participant(m1->method_holder());
1500 wf.add_participant(m2->method_holder());
1501 return wf.find_witness_definer(ctxk, changes);
1502 }
1503
1504 // Find the set of all non-abstract methods under ctxk that match m[0].
1505 // (The method m[0] must be defined or inherited in ctxk.)
1506 // Include m itself in the set, unless it is abstract.
1507 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1508 // (The length may be zero if no concrete methods are found anywhere.)
1509 // If there are too many concrete methods to fit in marray, return -1.
1510 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1511 int mlen,
1512 Method* marray[]) {
1513 Method* m0 = marray[0];
1514 ClassHierarchyWalker wf(m0);
1515 assert(wf.check_method_context(ctxk, m0), "proper context");
1516 wf.record_witnesses(mlen);
1517 bool participants_hide_witnesses = true;
1518 Klass* wit = wf.find_witness_definer(ctxk);
1519 if (wit != NULL) return -1; // Too many witnesses.
1520 int num = wf.num_participants();
1521 assert(num <= mlen, "oob");
1522 // Keep track of whether m is also part of the result set.
1523 int mfill = 0;
1524 assert(marray[mfill] == m0, "sanity");
1525 if (Dependencies::is_concrete_method(m0))
1526 mfill++; // keep m0 as marray[0], the first result
1527 for (int i = 0; i < num; i++) {
1528 Method* fm = wf.found_method(i);
1529 if (fm == m0) continue; // Already put this guy in the list.
1530 if (mfill == mlen) {
1531 return -1; // Oops. Too many methods after all!
1532 }
1533 marray[mfill++] = fm;
1534 }
1535 #ifndef PRODUCT
1536 // Make sure the dependency mechanism will pass this discovery:
1537 if (VerifyDependencies) {
1538 // Turn off dependency tracing while actually testing deps.
1539 FlagSetting fs(TraceDependencies, false);
1540 switch (mfill) {
1541 case 1:
1542 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1543 "verify dep.");
1544 break;
1545 case 2:
1546 guarantee(NULL == (void *)
1547 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1548 "verify dep.");
1549 break;
1550 default:
1551 ShouldNotReachHere(); // mlen > 2 yet supported
1552 }
1553 }
1554 #endif //PRODUCT
1555 return mfill;
1556 }
1557
1558
1559 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1560 Klass* search_at = ctxk;
1561 if (changes != NULL)
1562 search_at = changes->new_type(); // just look at the new bit
1563 return find_finalizable_subclass(search_at);
1564 }
1565
1566
1567 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1568 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1569 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1570 if (changes == NULL) {
1571 // Validate all CallSites
1572 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1573 return call_site->klass(); // assertion failed
1574 } else {
1575 // Validate the given CallSite
1576 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1577 assert(method_handle != changes->method_handle(), "must be");
1578 return call_site->klass(); // assertion failed
1579 }
1580 }
1581 return NULL; // assertion still valid
1582 }
1583
1584
1585 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1586 if (witness != NULL) {
1587 if (TraceDependencies) {
1588 print_dependency(witness, /*verbose=*/ true);
1589 }
1590 // The following is a no-op unless logging is enabled:
1591 log_dependency(witness);
1592 }
1593 }
1594
1595
1596 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1597 assert_locked_or_safepoint(Compile_lock);
1598 Dependencies::check_valid_dependency_type(type());
1599
1600 Klass* witness = NULL;
1601 switch (type()) {
1602 case evol_method:
1603 witness = check_evol_method(method_argument(0));
1604 break;
1605 case leaf_type:
1606 witness = check_leaf_type(context_type());
1607 break;
1608 case abstract_with_unique_concrete_subtype:
1609 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1610 break;
1611 case abstract_with_no_concrete_subtype:
1612 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1613 break;
1614 case concrete_with_no_concrete_subtype:
1615 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1616 break;
1617 case unique_concrete_method:
1618 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1619 break;
1620 case abstract_with_exclusive_concrete_subtypes_2:
1621 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1622 break;
1623 case exclusive_concrete_methods_2:
1624 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1625 break;
1626 case no_finalizable_subclasses:
1627 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1628 break;
1629 default:
1630 witness = NULL;
1631 break;
1632 }
1633 trace_and_log_witness(witness);
1634 return witness;
1635 }
1636
1637
1638 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1639 assert_locked_or_safepoint(Compile_lock);
1640 Dependencies::check_valid_dependency_type(type());
1641
1642 Klass* witness = NULL;
1643 switch (type()) {
1644 case call_site_target_value:
1645 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1646 break;
1647 default:
1648 witness = NULL;
1649 break;
1650 }
1651 trace_and_log_witness(witness);
1652 return witness;
1653 }
1654
1655
1656 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1657 // Handle klass dependency
1658 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1659 return check_klass_dependency(changes.as_klass_change());
1660
1661 // Handle CallSite dependency
1662 if (changes.is_call_site_change())
1663 return check_call_site_dependency(changes.as_call_site_change());
1664
1665 // irrelevant dependency; skip it
1666 return NULL;
1667 }
1668
1669
1670 void DepChange::print() {
1671 int nsup = 0, nint = 0;
1672 for (ContextStream str(*this); str.next(); ) {
1673 Klass* k = str.klass();
1674 switch (str.change_type()) {
1675 case Change_new_type:
1676 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1677 break;
1678 case Change_new_sub:
1679 if (!WizardMode) {
1680 ++nsup;
1681 } else {
1682 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1683 }
1684 break;
1685 case Change_new_impl:
1686 if (!WizardMode) {
1687 ++nint;
1688 } else {
1689 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1690 }
1691 break;
1692 }
1693 }
1694 if (nsup + nint != 0) {
1695 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1696 }
1697 }
1698
1699 void DepChange::ContextStream::start() {
1700 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1701 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1702 _klass = new_type;
1703 _ti_base = NULL;
1704 _ti_index = 0;
1705 _ti_limit = 0;
1706 }
1707
1708 bool DepChange::ContextStream::next() {
1709 switch (_change_type) {
1710 case Start_Klass: // initial state; _klass is the new type
1711 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1712 _ti_index = 0;
1713 _change_type = Change_new_type;
1714 return true;
1715 case Change_new_type:
1716 // fall through:
1717 _change_type = Change_new_sub;
1718 case Change_new_sub:
1719 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1720 {
1721 _klass = InstanceKlass::cast(_klass)->super();
1722 if (_klass != NULL) {
1723 return true;
1724 }
1725 }
1726 // else set up _ti_limit and fall through:
1727 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1728 _change_type = Change_new_impl;
1729 case Change_new_impl:
1730 if (_ti_index < _ti_limit) {
1731 _klass = _ti_base->at(_ti_index++);
1732 return true;
1733 }
1734 // fall through:
1735 _change_type = NO_CHANGE; // iterator is exhausted
1736 case NO_CHANGE:
1737 break;
1738 default:
1739 ShouldNotReachHere();
1740 }
1741 return false;
1742 }
1743
1744 void KlassDepChange::initialize() {
1745 // entire transaction must be under this lock:
1746 assert_lock_strong(Compile_lock);
1747
1748 // Mark all dependee and all its superclasses
1749 // Mark transitive interfaces
1750 for (ContextStream str(*this); str.next(); ) {
1751 Klass* d = str.klass();
1752 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1753 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1754 }
1755 }
1756
1757 KlassDepChange::~KlassDepChange() {
1758 // Unmark all dependee and all its superclasses
1759 // Unmark transitive interfaces
1760 for (ContextStream str(*this); str.next(); ) {
1761 Klass* d = str.klass();
1762 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1763 }
1764 }
1765
1766 bool KlassDepChange::involves_context(Klass* k) {
1767 if (k == NULL || !k->oop_is_instance()) {
1768 return false;
1769 }
1770 InstanceKlass* ik = InstanceKlass::cast(k);
1771 bool is_contained = ik->is_marked_dependent();
1772 assert(is_contained == new_type()->is_subtype_of(k),
1773 "correct marking of potential context types");
1774 return is_contained;
1775 }
1776
1777 #ifndef PRODUCT
1778 void Dependencies::print_statistics() {
1779 if (deps_find_witness_print != 0) {
1780 // Call one final time, to flush out the data.
1781 deps_find_witness_print = -1;
1782 count_find_witness_calls();
1783 }
1784 }
1785 #endif