1 /*
2 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciArrayKlass.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "ci/ciKlass.hpp"
29 #include "ci/ciMethod.hpp"
30 #include "classfile/javaClasses.inline.hpp"
31 #include "code/dependencies.hpp"
32 #include "compiler/compileLog.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/handles.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/thread.inline.hpp"
37 #include "utilities/copy.hpp"
38
39
40 #ifdef ASSERT
41 static bool must_be_in_vm() {
42 Thread* thread = Thread::current();
43 if (thread->is_Java_thread())
44 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
45 else
46 return true; //something like this: thread->is_VM_thread();
47 }
48 #endif //ASSERT
49
50 void Dependencies::initialize(ciEnv* env) {
51 Arena* arena = env->arena();
52 _oop_recorder = env->oop_recorder();
53 _log = env->log();
54 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
55 DEBUG_ONLY(_deps[end_marker] = NULL);
56 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
57 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
58 }
59 _content_bytes = NULL;
60 _size_in_bytes = (size_t)-1;
61
62 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
63 }
64
65 void Dependencies::assert_evol_method(ciMethod* m) {
66 assert_common_1(evol_method, m);
67 }
68
69 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
70 if (ctxk->is_array_klass()) {
71 // As a special case, support this assertion on an array type,
72 // which reduces to an assertion on its element type.
73 // Note that this cannot be done with assertions that
74 // relate to concreteness or abstractness.
75 ciType* elemt = ctxk->as_array_klass()->base_element_type();
76 if (!elemt->is_instance_klass()) return; // Ex: int[][]
77 ctxk = elemt->as_instance_klass();
78 //if (ctxk->is_final()) return; // Ex: String[][]
79 }
80 check_ctxk(ctxk);
81 assert_common_1(leaf_type, ctxk);
82 }
83
84 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
85 check_ctxk_abstract(ctxk);
86 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
87 }
88
89 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
90 check_ctxk_abstract(ctxk);
91 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
92 }
93
94 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
95 check_ctxk_concrete(ctxk);
96 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
97 }
98
99 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
100 check_ctxk(ctxk);
101 assert_common_2(unique_concrete_method, ctxk, uniqm);
102 }
103
104 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
105 check_ctxk(ctxk);
106 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
107 }
108
109 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
110 check_ctxk(ctxk);
111 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
112 }
113
114 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
115 check_ctxk(ctxk);
116 assert_common_1(no_finalizable_subclasses, ctxk);
117 }
118
119 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
120 check_ctxk(call_site->klass());
121 assert_common_2(call_site_target_value, call_site, method_handle);
122 }
123
124 // Helper function. If we are adding a new dep. under ctxk2,
125 // try to find an old dep. under a broader* ctxk1. If there is
126 //
127 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
128 int ctxk_i, ciKlass* ctxk2) {
129 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
130 if (ctxk2->is_subtype_of(ctxk1)) {
131 return true; // success, and no need to change
132 } else if (ctxk1->is_subtype_of(ctxk2)) {
133 // new context class fully subsumes previous one
134 deps->at_put(ctxk_i, ctxk2);
135 return true;
136 } else {
137 return false;
138 }
139 }
140
141 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
142 assert(dep_args(dept) == 1, "sanity");
143 log_dependency(dept, x);
144 GrowableArray<ciBaseObject*>* deps = _deps[dept];
145
146 // see if the same (or a similar) dep is already recorded
147 if (note_dep_seen(dept, x)) {
148 assert(deps->find(x) >= 0, "sanity");
149 } else {
150 deps->append(x);
151 }
152 }
153
154 void Dependencies::assert_common_2(DepType dept,
155 ciBaseObject* x0, ciBaseObject* x1) {
156 assert(dep_args(dept) == 2, "sanity");
157 log_dependency(dept, x0, x1);
158 GrowableArray<ciBaseObject*>* deps = _deps[dept];
159
160 // see if the same (or a similar) dep is already recorded
161 bool has_ctxk = has_explicit_context_arg(dept);
162 if (has_ctxk) {
163 assert(dep_context_arg(dept) == 0, "sanity");
164 if (note_dep_seen(dept, x1)) {
165 // look in this bucket for redundant assertions
166 const int stride = 2;
167 for (int i = deps->length(); (i -= stride) >= 0; ) {
168 ciBaseObject* y1 = deps->at(i+1);
169 if (x1 == y1) { // same subject; check the context
170 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
171 return;
172 }
173 }
174 }
175 }
176 } else {
177 assert(dep_implicit_context_arg(dept) == 0, "sanity");
178 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
179 // look in this bucket for redundant assertions
180 const int stride = 2;
181 for (int i = deps->length(); (i -= stride) >= 0; ) {
182 ciBaseObject* y0 = deps->at(i+0);
183 ciBaseObject* y1 = deps->at(i+1);
184 if (x0 == y0 && x1 == y1) {
185 return;
186 }
187 }
188 }
189 }
190
191 // append the assertion in the correct bucket:
192 deps->append(x0);
193 deps->append(x1);
194 }
195
196 void Dependencies::assert_common_3(DepType dept,
197 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
198 assert(dep_context_arg(dept) == 0, "sanity");
199 assert(dep_args(dept) == 3, "sanity");
200 log_dependency(dept, ctxk, x, x2);
201 GrowableArray<ciBaseObject*>* deps = _deps[dept];
202
203 // try to normalize an unordered pair:
204 bool swap = false;
205 switch (dept) {
206 case abstract_with_exclusive_concrete_subtypes_2:
207 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
208 break;
209 case exclusive_concrete_methods_2:
210 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
211 break;
212 }
213 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
214
215 // see if the same (or a similar) dep is already recorded
216 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
217 // look in this bucket for redundant assertions
218 const int stride = 3;
219 for (int i = deps->length(); (i -= stride) >= 0; ) {
220 ciBaseObject* y = deps->at(i+1);
221 ciBaseObject* y2 = deps->at(i+2);
222 if (x == y && x2 == y2) { // same subjects; check the context
223 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
224 return;
225 }
226 }
227 }
228 }
229 // append the assertion in the correct bucket:
230 deps->append(ctxk);
231 deps->append(x);
232 deps->append(x2);
233 }
234
235 /// Support for encoding dependencies into an nmethod:
236
237 void Dependencies::copy_to(nmethod* nm) {
238 address beg = nm->dependencies_begin();
239 address end = nm->dependencies_end();
240 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
241 Copy::disjoint_words((HeapWord*) content_bytes(),
242 (HeapWord*) beg,
243 size_in_bytes() / sizeof(HeapWord));
244 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
245 }
246
247 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
248 for (int i = 0; i < narg; i++) {
249 int diff = p1[i]->ident() - p2[i]->ident();
250 if (diff != 0) return diff;
251 }
252 return 0;
253 }
254 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
255 { return sort_dep(p1, p2, 1); }
256 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
257 { return sort_dep(p1, p2, 2); }
258 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
259 { return sort_dep(p1, p2, 3); }
260
261 void Dependencies::sort_all_deps() {
262 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
263 DepType dept = (DepType)deptv;
264 GrowableArray<ciBaseObject*>* deps = _deps[dept];
265 if (deps->length() <= 1) continue;
266 switch (dep_args(dept)) {
267 case 1: deps->sort(sort_dep_arg_1, 1); break;
268 case 2: deps->sort(sort_dep_arg_2, 2); break;
269 case 3: deps->sort(sort_dep_arg_3, 3); break;
270 default: ShouldNotReachHere();
271 }
272 }
273 }
274
275 size_t Dependencies::estimate_size_in_bytes() {
276 size_t est_size = 100;
277 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
278 DepType dept = (DepType)deptv;
279 GrowableArray<ciBaseObject*>* deps = _deps[dept];
280 est_size += deps->length()*2; // tags and argument(s)
281 }
282 return est_size;
283 }
284
285 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
286 switch (dept) {
287 case abstract_with_exclusive_concrete_subtypes_2:
288 return x->as_metadata()->as_klass();
289 case unique_concrete_method:
290 case exclusive_concrete_methods_2:
291 return x->as_metadata()->as_method()->holder();
292 }
293 return NULL; // let NULL be NULL
294 }
295
296 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
297 assert(must_be_in_vm(), "raw oops here");
298 switch (dept) {
299 case abstract_with_exclusive_concrete_subtypes_2:
300 assert(x->is_klass(), "sanity");
301 return (Klass*) x;
302 case unique_concrete_method:
303 case exclusive_concrete_methods_2:
304 assert(x->is_method(), "sanity");
305 return ((Method*)x)->method_holder();
306 }
307 return NULL; // let NULL be NULL
308 }
309
310 void Dependencies::encode_content_bytes() {
311 sort_all_deps();
312
313 // cast is safe, no deps can overflow INT_MAX
314 CompressedWriteStream bytes((int)estimate_size_in_bytes());
315
316 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
317 DepType dept = (DepType)deptv;
318 GrowableArray<ciBaseObject*>* deps = _deps[dept];
319 if (deps->length() == 0) continue;
320 int stride = dep_args(dept);
321 int ctxkj = dep_context_arg(dept); // -1 if no context arg
322 assert(stride > 0, "sanity");
323 for (int i = 0; i < deps->length(); i += stride) {
324 jbyte code_byte = (jbyte)dept;
325 int skipj = -1;
326 if (ctxkj >= 0 && ctxkj+1 < stride) {
327 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
328 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
329 if (ctxk == ctxk_encoded_as_null(dept, x)) {
330 skipj = ctxkj; // we win: maybe one less oop to keep track of
331 code_byte |= default_context_type_bit;
332 }
333 }
334 bytes.write_byte(code_byte);
335 for (int j = 0; j < stride; j++) {
336 if (j == skipj) continue;
337 ciBaseObject* v = deps->at(i+j);
338 int idx;
339 if (v->is_object()) {
340 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
341 } else {
342 ciMetadata* meta = v->as_metadata();
343 idx = _oop_recorder->find_index(meta->constant_encoding());
344 }
345 bytes.write_int(idx);
346 }
347 }
348 }
349
350 // write a sentinel byte to mark the end
351 bytes.write_byte(end_marker);
352
353 // round it out to a word boundary
354 while (bytes.position() % sizeof(HeapWord) != 0) {
355 bytes.write_byte(end_marker);
356 }
357
358 // check whether the dept byte encoding really works
359 assert((jbyte)default_context_type_bit != 0, "byte overflow");
360
361 _content_bytes = bytes.buffer();
362 _size_in_bytes = bytes.position();
363 }
364
365
366 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
367 "end_marker",
368 "evol_method",
369 "leaf_type",
370 "abstract_with_unique_concrete_subtype",
371 "abstract_with_no_concrete_subtype",
372 "concrete_with_no_concrete_subtype",
373 "unique_concrete_method",
374 "abstract_with_exclusive_concrete_subtypes_2",
375 "exclusive_concrete_methods_2",
376 "no_finalizable_subclasses",
377 "call_site_target_value"
378 };
379
380 int Dependencies::_dep_args[TYPE_LIMIT] = {
381 -1,// end_marker
382 1, // evol_method m
383 1, // leaf_type ctxk
384 2, // abstract_with_unique_concrete_subtype ctxk, k
385 1, // abstract_with_no_concrete_subtype ctxk
386 1, // concrete_with_no_concrete_subtype ctxk
387 2, // unique_concrete_method ctxk, m
388 3, // unique_concrete_subtypes_2 ctxk, k1, k2
389 3, // unique_concrete_methods_2 ctxk, m1, m2
390 1, // no_finalizable_subclasses ctxk
391 2 // call_site_target_value call_site, method_handle
392 };
393
394 const char* Dependencies::dep_name(Dependencies::DepType dept) {
395 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
396 return _dep_name[dept];
397 }
398
399 int Dependencies::dep_args(Dependencies::DepType dept) {
400 if (!dept_in_mask(dept, all_types)) return -1;
401 return _dep_args[dept];
402 }
403
404 void Dependencies::check_valid_dependency_type(DepType dept) {
405 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
406 }
407
408 // for the sake of the compiler log, print out current dependencies:
409 void Dependencies::log_all_dependencies() {
410 if (log() == NULL) return;
411 ResourceMark rm;
412 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
413 DepType dept = (DepType)deptv;
414 GrowableArray<ciBaseObject*>* deps = _deps[dept];
415 int deplen = deps->length();
416 if (deplen == 0) {
417 continue;
418 }
419 int stride = dep_args(dept);
420 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
421 for (int i = 0; i < deps->length(); i += stride) {
422 for (int j = 0; j < stride; j++) {
423 // flush out the identities before printing
424 ciargs->push(deps->at(i+j));
425 }
426 write_dependency_to(log(), dept, ciargs);
427 ciargs->clear();
428 }
429 guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
430 }
431 }
432
433 void Dependencies::write_dependency_to(CompileLog* log,
434 DepType dept,
435 GrowableArray<DepArgument>* args,
436 Klass* witness) {
437 if (log == NULL) {
438 return;
439 }
440 ResourceMark rm;
441 ciEnv* env = ciEnv::current();
442 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
443 for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
444 DepArgument arg = *it;
445 if (arg.is_oop()) {
446 ciargs->push(env->get_object(arg.oop_value()));
447 } else {
448 ciargs->push(env->get_metadata(arg.metadata_value()));
449 }
450 }
451 int argslen = ciargs->length();
452 Dependencies::write_dependency_to(log, dept, ciargs, witness);
453 guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
454 }
455
456 void Dependencies::write_dependency_to(CompileLog* log,
457 DepType dept,
458 GrowableArray<ciBaseObject*>* args,
459 Klass* witness) {
460 if (log == NULL) {
461 return;
462 }
463 ResourceMark rm;
464 GrowableArray<int>* argids = new GrowableArray<int>(args->length());
465 for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
466 ciBaseObject* obj = *it;
467 if (obj->is_object()) {
468 argids->push(log->identify(obj->as_object()));
469 } else {
470 argids->push(log->identify(obj->as_metadata()));
471 }
472 }
473 if (witness != NULL) {
474 log->begin_elem("dependency_failed");
475 } else {
476 log->begin_elem("dependency");
477 }
478 log->print(" type='%s'", dep_name(dept));
479 const int ctxkj = dep_context_arg(dept); // -1 if no context arg
480 if (ctxkj >= 0 && ctxkj < argids->length()) {
481 log->print(" ctxk='%d'", argids->at(ctxkj));
482 }
483 // write remaining arguments, if any.
484 for (int j = 0; j < argids->length(); j++) {
485 if (j == ctxkj) continue; // already logged
486 if (j == 1) {
487 log->print( " x='%d'", argids->at(j));
488 } else {
489 log->print(" x%d='%d'", j, argids->at(j));
490 }
491 }
492 if (witness != NULL) {
493 log->object("witness", witness);
494 log->stamp();
495 }
496 log->end_elem();
497 }
498
499 void Dependencies::write_dependency_to(xmlStream* xtty,
500 DepType dept,
501 GrowableArray<DepArgument>* args,
502 Klass* witness) {
503 if (xtty == NULL) {
504 return;
505 }
506 ResourceMark rm;
507 ttyLocker ttyl;
508 int ctxkj = dep_context_arg(dept); // -1 if no context arg
509 if (witness != NULL) {
510 xtty->begin_elem("dependency_failed");
511 } else {
512 xtty->begin_elem("dependency");
513 }
514 xtty->print(" type='%s'", dep_name(dept));
515 if (ctxkj >= 0) {
516 xtty->object("ctxk", args->at(ctxkj).metadata_value());
517 }
518 // write remaining arguments, if any.
519 for (int j = 0; j < args->length(); j++) {
520 if (j == ctxkj) continue; // already logged
521 DepArgument arg = args->at(j);
522 if (j == 1) {
523 if (arg.is_oop()) {
524 xtty->object("x", arg.oop_value());
525 } else {
526 xtty->object("x", arg.metadata_value());
527 }
528 } else {
529 char xn[10]; sprintf(xn, "x%d", j);
530 if (arg.is_oop()) {
531 xtty->object(xn, arg.oop_value());
532 } else {
533 xtty->object(xn, arg.metadata_value());
534 }
535 }
536 }
537 if (witness != NULL) {
538 xtty->object("witness", witness);
539 xtty->stamp();
540 }
541 xtty->end_elem();
542 }
543
544 void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
545 Klass* witness) {
546 ResourceMark rm;
547 ttyLocker ttyl; // keep the following output all in one block
548 tty->print_cr("%s of type %s",
549 (witness == NULL)? "Dependency": "Failed dependency",
550 dep_name(dept));
551 // print arguments
552 int ctxkj = dep_context_arg(dept); // -1 if no context arg
553 for (int j = 0; j < args->length(); j++) {
554 DepArgument arg = args->at(j);
555 bool put_star = false;
556 if (arg.is_null()) continue;
557 const char* what;
558 if (j == ctxkj) {
559 assert(arg.is_metadata(), "must be");
560 what = "context";
561 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
562 } else if (arg.is_method()) {
563 what = "method ";
564 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value(), NULL);
565 } else if (arg.is_klass()) {
566 what = "class ";
567 } else {
568 what = "object ";
569 }
570 tty->print(" %s = %s", what, (put_star? "*": ""));
571 if (arg.is_klass()) {
572 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
573 } else if (arg.is_method()) {
574 ((Method*)arg.metadata_value())->print_value();
575 } else if (arg.is_oop()) {
576 arg.oop_value()->print_value_on(tty);
577 } else {
578 ShouldNotReachHere(); // Provide impl for this type.
579 }
580
581 tty->cr();
582 }
583 if (witness != NULL) {
584 bool put_star = !Dependencies::is_concrete_klass(witness);
585 tty->print_cr(" witness = %s%s",
586 (put_star? "*": ""),
587 witness->external_name());
588 }
589 }
590
591 void Dependencies::DepStream::log_dependency(Klass* witness) {
592 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
593 ResourceMark rm;
594 const int nargs = argument_count();
595 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
596 for (int j = 0; j < nargs; j++) {
597 if (type() == call_site_target_value) {
598 args->push(argument_oop(j));
599 } else {
600 args->push(argument(j));
601 }
602 }
603 int argslen = args->length();
604 if (_deps != NULL && _deps->log() != NULL) {
605 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
606 } else {
607 Dependencies::write_dependency_to(xtty, type(), args, witness);
608 }
609 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
610 }
611
612 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
613 ResourceMark rm;
614 int nargs = argument_count();
615 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
616 for (int j = 0; j < nargs; j++) {
617 if (type() == call_site_target_value) {
618 args->push(argument_oop(j));
619 } else {
620 args->push(argument(j));
621 }
622 }
623 int argslen = args->length();
624 Dependencies::print_dependency(type(), args, witness);
625 if (verbose) {
626 if (_code != NULL) {
627 tty->print(" code: ");
628 _code->print_value_on(tty);
629 tty->cr();
630 }
631 }
632 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
633 }
634
635
636 /// Dependency stream support (decodes dependencies from an nmethod):
637
638 #ifdef ASSERT
639 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
640 assert(must_be_in_vm(), "raw oops here");
641 _byte_limit = byte_limit;
642 _type = (DepType)(end_marker-1); // defeat "already at end" assert
643 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
644 }
645 #endif //ASSERT
646
647 bool Dependencies::DepStream::next() {
648 assert(_type != end_marker, "already at end");
649 if (_bytes.position() == 0 && _code != NULL
650 && _code->dependencies_size() == 0) {
651 // Method has no dependencies at all.
652 return false;
653 }
654 int code_byte = (_bytes.read_byte() & 0xFF);
655 if (code_byte == end_marker) {
656 DEBUG_ONLY(_type = end_marker);
657 return false;
658 } else {
659 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
660 code_byte -= ctxk_bit;
661 DepType dept = (DepType)code_byte;
662 _type = dept;
663 Dependencies::check_valid_dependency_type(dept);
664 int stride = _dep_args[dept];
665 assert(stride == dep_args(dept), "sanity");
666 int skipj = -1;
667 if (ctxk_bit != 0) {
668 skipj = 0; // currently the only context argument is at zero
669 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
670 }
671 for (int j = 0; j < stride; j++) {
672 _xi[j] = (j == skipj)? 0: _bytes.read_int();
673 }
674 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
675 return true;
676 }
677 }
678
679 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
680 Metadata* o = NULL;
681 if (_code != NULL) {
682 o = _code->metadata_at(i);
683 } else {
684 o = _deps->oop_recorder()->metadata_at(i);
685 }
686 return o;
687 }
688
689 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
690 return (_code != NULL)
691 ? _code->oop_at(i)
692 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
693 }
694
695 Metadata* Dependencies::DepStream::argument(int i) {
696 Metadata* result = recorded_metadata_at(argument_index(i));
697
698 if (result == NULL) { // Explicit context argument can be compressed
699 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
700 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
701 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
702 }
703 }
704
705 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
706 return result;
707 }
708
709 /**
710 * Returns a unique identifier for each dependency argument.
711 */
712 uintptr_t Dependencies::DepStream::get_identifier(int i) {
713 if (has_oop_argument()) {
714 return (uintptr_t)(oopDesc*)argument_oop(i);
715 } else {
716 return (uintptr_t)argument(i);
717 }
718 }
719
720 oop Dependencies::DepStream::argument_oop(int i) {
721 oop result = recorded_oop_at(argument_index(i));
722 assert(result == NULL || result->is_oop(), "must be");
723 return result;
724 }
725
726 Klass* Dependencies::DepStream::context_type() {
727 assert(must_be_in_vm(), "raw oops here");
728
729 // Most dependencies have an explicit context type argument.
730 {
731 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
732 if (ctxkj >= 0) {
733 Metadata* k = argument(ctxkj);
734 assert(k != NULL && k->is_klass(), "type check");
735 return (Klass*)k;
736 }
737 }
738
739 // Some dependencies are using the klass of the first object
740 // argument as implicit context type (e.g. call_site_target_value).
741 {
742 int ctxkj = dep_implicit_context_arg(type());
743 if (ctxkj >= 0) {
744 Klass* k = argument_oop(ctxkj)->klass();
745 assert(k != NULL && k->is_klass(), "type check");
746 return (Klass*) k;
747 }
748 }
749
750 // And some dependencies don't have a context type at all,
751 // e.g. evol_method.
752 return NULL;
753 }
754
755 // ----------------- DependencySignature --------------------------------------
756 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
757 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
758 return false;
759 }
760
761 for (int i = 0; i < s1.args_count(); i++) {
762 if (s1.arg(i) != s2.arg(i)) {
763 return false;
764 }
765 }
766 return true;
767 }
768
769 /// Checking dependencies:
770
771 // This hierarchy walker inspects subtypes of a given type,
772 // trying to find a "bad" class which breaks a dependency.
773 // Such a class is called a "witness" to the broken dependency.
774 // While searching around, we ignore "participants", which
775 // are already known to the dependency.
776 class ClassHierarchyWalker {
777 public:
778 enum { PARTICIPANT_LIMIT = 3 };
779
780 private:
781 // optional method descriptor to check for:
782 Symbol* _name;
783 Symbol* _signature;
784
785 // special classes which are not allowed to be witnesses:
786 Klass* _participants[PARTICIPANT_LIMIT+1];
787 int _num_participants;
788
789 // cache of method lookups
790 Method* _found_methods[PARTICIPANT_LIMIT+1];
791
792 // if non-zero, tells how many witnesses to convert to participants
793 int _record_witnesses;
794
795 void initialize(Klass* participant) {
796 _record_witnesses = 0;
797 _participants[0] = participant;
798 _found_methods[0] = NULL;
799 _num_participants = 0;
800 if (participant != NULL) {
801 // Terminating NULL.
802 _participants[1] = NULL;
803 _found_methods[1] = NULL;
804 _num_participants = 1;
805 }
806 }
807
808 void initialize_from_method(Method* m) {
809 assert(m != NULL && m->is_method(), "sanity");
810 _name = m->name();
811 _signature = m->signature();
812 }
813
814 public:
815 // The walker is initialized to recognize certain methods and/or types
816 // as friendly participants.
817 ClassHierarchyWalker(Klass* participant, Method* m) {
818 initialize_from_method(m);
819 initialize(participant);
820 }
821 ClassHierarchyWalker(Method* m) {
822 initialize_from_method(m);
823 initialize(NULL);
824 }
825 ClassHierarchyWalker(Klass* participant = NULL) {
826 _name = NULL;
827 _signature = NULL;
828 initialize(participant);
829 }
830
831 // This is common code for two searches: One for concrete subtypes,
832 // the other for concrete method implementations and overrides.
833 bool doing_subtype_search() {
834 return _name == NULL;
835 }
836
837 int num_participants() { return _num_participants; }
838 Klass* participant(int n) {
839 assert((uint)n <= (uint)_num_participants, "oob");
840 return _participants[n];
841 }
842
843 // Note: If n==num_participants, returns NULL.
844 Method* found_method(int n) {
845 assert((uint)n <= (uint)_num_participants, "oob");
846 Method* fm = _found_methods[n];
847 assert(n == _num_participants || fm != NULL, "proper usage");
848 if (fm != NULL && fm->method_holder() != _participants[n]) {
849 // Default methods from interfaces can be added to classes. In
850 // that case the holder of the method is not the class but the
851 // interface where it's defined.
852 assert(fm->is_default_method(), "sanity");
853 return NULL;
854 }
855 return fm;
856 }
857
858 #ifdef ASSERT
859 // Assert that m is inherited into ctxk, without intervening overrides.
860 // (May return true even if this is not true, in corner cases where we punt.)
861 bool check_method_context(Klass* ctxk, Method* m) {
862 if (m->method_holder() == ctxk)
863 return true; // Quick win.
864 if (m->is_private())
865 return false; // Quick lose. Should not happen.
866 if (!(m->is_public() || m->is_protected()))
867 // The override story is complex when packages get involved.
868 return true; // Must punt the assertion to true.
869 Klass* k = ctxk;
870 Method* lm = k->lookup_method(m->name(), m->signature());
871 if (lm == NULL && k->oop_is_instance()) {
872 // It might be an interface method
873 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
874 m->signature());
875 }
876 if (lm == m)
877 // Method m is inherited into ctxk.
878 return true;
879 if (lm != NULL) {
880 if (!(lm->is_public() || lm->is_protected())) {
881 // Method is [package-]private, so the override story is complex.
882 return true; // Must punt the assertion to true.
883 }
884 if (lm->is_static()) {
885 // Static methods don't override non-static so punt
886 return true;
887 }
888 if ( !Dependencies::is_concrete_method(lm, k)
889 && !Dependencies::is_concrete_method(m, ctxk)
890 && lm->method_holder()->is_subtype_of(m->method_holder()))
891 // Method m is overridden by lm, but both are non-concrete.
892 return true;
893 }
894 ResourceMark rm;
895 tty->print_cr("Dependency method not found in the associated context:");
896 tty->print_cr(" context = %s", ctxk->external_name());
897 tty->print( " method = "); m->print_short_name(tty); tty->cr();
898 if (lm != NULL) {
899 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
900 }
901 return false;
902 }
903 #endif
904
905 void add_participant(Klass* participant) {
906 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
907 int np = _num_participants++;
908 _participants[np] = participant;
909 _participants[np+1] = NULL;
910 _found_methods[np+1] = NULL;
911 }
912
913 void record_witnesses(int add) {
914 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
915 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
916 _record_witnesses = add;
917 }
918
919 bool is_witness(Klass* k) {
920 if (doing_subtype_search()) {
921 return Dependencies::is_concrete_klass(k);
922 } else if (!k->oop_is_instance()) {
923 return false; // no methods to find in an array type
924 } else {
925 // Search class hierarchy first.
926 Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature);
927 if (!Dependencies::is_concrete_method(m, k)) {
928 // Check interface defaults also, if any exist.
929 Array<Method*>* default_methods = InstanceKlass::cast(k)->default_methods();
930 if (default_methods == NULL)
931 return false;
932 m = InstanceKlass::cast(k)->find_method(default_methods, _name, _signature);
933 if (!Dependencies::is_concrete_method(m, NULL))
934 return false;
935 }
936 _found_methods[_num_participants] = m;
937 // Note: If add_participant(k) is called,
938 // the method m will already be memoized for it.
939 return true;
940 }
941 }
942
943 bool is_participant(Klass* k) {
944 if (k == _participants[0]) {
945 return true;
946 } else if (_num_participants <= 1) {
947 return false;
948 } else {
949 return in_list(k, &_participants[1]);
950 }
951 }
952 bool ignore_witness(Klass* witness) {
953 if (_record_witnesses == 0) {
954 return false;
955 } else {
956 --_record_witnesses;
957 add_participant(witness);
958 return true;
959 }
960 }
961 static bool in_list(Klass* x, Klass** list) {
962 for (int i = 0; ; i++) {
963 Klass* y = list[i];
964 if (y == NULL) break;
965 if (y == x) return true;
966 }
967 return false; // not in list
968 }
969
970 private:
971 // the actual search method:
972 Klass* find_witness_anywhere(Klass* context_type,
973 bool participants_hide_witnesses,
974 bool top_level_call = true);
975 // the spot-checking version:
976 Klass* find_witness_in(KlassDepChange& changes,
977 Klass* context_type,
978 bool participants_hide_witnesses);
979 public:
980 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
981 assert(doing_subtype_search(), "must set up a subtype search");
982 // When looking for unexpected concrete types,
983 // do not look beneath expected ones.
984 const bool participants_hide_witnesses = true;
985 // CX > CC > C' is OK, even if C' is new.
986 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
987 if (changes != NULL) {
988 return find_witness_in(*changes, context_type, participants_hide_witnesses);
989 } else {
990 return find_witness_anywhere(context_type, participants_hide_witnesses);
991 }
992 }
993 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
994 assert(!doing_subtype_search(), "must set up a method definer search");
995 // When looking for unexpected concrete methods,
996 // look beneath expected ones, to see if there are overrides.
997 const bool participants_hide_witnesses = true;
998 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
999 if (changes != NULL) {
1000 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
1001 } else {
1002 return find_witness_anywhere(context_type, !participants_hide_witnesses);
1003 }
1004 }
1005 };
1006
1007 #ifndef PRODUCT
1008 static int deps_find_witness_calls = 0;
1009 static int deps_find_witness_steps = 0;
1010 static int deps_find_witness_recursions = 0;
1011 static int deps_find_witness_singles = 0;
1012 static int deps_find_witness_print = 0; // set to -1 to force a final print
1013 static bool count_find_witness_calls() {
1014 if (TraceDependencies || LogCompilation) {
1015 int pcount = deps_find_witness_print + 1;
1016 bool final_stats = (pcount == 0);
1017 bool initial_call = (pcount == 1);
1018 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
1019 if (pcount < 0) pcount = 1; // crude overflow protection
1020 deps_find_witness_print = pcount;
1021 if (VerifyDependencies && initial_call) {
1022 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
1023 }
1024 if (occasional_print || final_stats) {
1025 // Every now and then dump a little info about dependency searching.
1026 if (xtty != NULL) {
1027 ttyLocker ttyl;
1028 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
1029 deps_find_witness_calls,
1030 deps_find_witness_steps,
1031 deps_find_witness_recursions,
1032 deps_find_witness_singles);
1033 }
1034 if (final_stats || (TraceDependencies && WizardMode)) {
1035 ttyLocker ttyl;
1036 tty->print_cr("Dependency check (find_witness) "
1037 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
1038 deps_find_witness_calls,
1039 deps_find_witness_steps,
1040 (double)deps_find_witness_steps / deps_find_witness_calls,
1041 deps_find_witness_recursions,
1042 deps_find_witness_singles);
1043 }
1044 }
1045 return true;
1046 }
1047 return false;
1048 }
1049 #else
1050 #define count_find_witness_calls() (0)
1051 #endif //PRODUCT
1052
1053
1054 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1055 Klass* context_type,
1056 bool participants_hide_witnesses) {
1057 assert(changes.involves_context(context_type), "irrelevant dependency");
1058 Klass* new_type = changes.new_type();
1059
1060 (void)count_find_witness_calls();
1061 NOT_PRODUCT(deps_find_witness_singles++);
1062
1063 // Current thread must be in VM (not native mode, as in CI):
1064 assert(must_be_in_vm(), "raw oops here");
1065 // Must not move the class hierarchy during this check:
1066 assert_locked_or_safepoint(Compile_lock);
1067
1068 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1069 if (nof_impls > 1) {
1070 // Avoid this case: *I.m > { A.m, C }; B.m > C
1071 // %%% Until this is fixed more systematically, bail out.
1072 // See corresponding comment in find_witness_anywhere.
1073 return context_type;
1074 }
1075
1076 assert(!is_participant(new_type), "only old classes are participants");
1077 if (participants_hide_witnesses) {
1078 // If the new type is a subtype of a participant, we are done.
1079 for (int i = 0; i < num_participants(); i++) {
1080 Klass* part = participant(i);
1081 if (part == NULL) continue;
1082 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1083 "correct marking of participants, b/c new_type is unique");
1084 if (changes.involves_context(part)) {
1085 // new guy is protected from this check by previous participant
1086 return NULL;
1087 }
1088 }
1089 }
1090
1091 if (is_witness(new_type) &&
1092 !ignore_witness(new_type)) {
1093 return new_type;
1094 }
1095
1096 return NULL;
1097 }
1098
1099
1100 // Walk hierarchy under a context type, looking for unexpected types.
1101 // Do not report participant types, and recursively walk beneath
1102 // them only if participants_hide_witnesses is false.
1103 // If top_level_call is false, skip testing the context type,
1104 // because the caller has already considered it.
1105 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1106 bool participants_hide_witnesses,
1107 bool top_level_call) {
1108 // Current thread must be in VM (not native mode, as in CI):
1109 assert(must_be_in_vm(), "raw oops here");
1110 // Must not move the class hierarchy during this check:
1111 assert_locked_or_safepoint(Compile_lock);
1112
1113 bool do_counts = count_find_witness_calls();
1114
1115 // Check the root of the sub-hierarchy first.
1116 if (top_level_call) {
1117 if (do_counts) {
1118 NOT_PRODUCT(deps_find_witness_calls++);
1119 NOT_PRODUCT(deps_find_witness_steps++);
1120 }
1121 if (is_participant(context_type)) {
1122 if (participants_hide_witnesses) return NULL;
1123 // else fall through to search loop...
1124 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1125 // The context is an abstract class or interface, to start with.
1126 return context_type;
1127 }
1128 }
1129
1130 // Now we must check each implementor and each subclass.
1131 // Use a short worklist to avoid blowing the stack.
1132 // Each worklist entry is a *chain* of subklass siblings to process.
1133 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1134 Klass* chains[CHAINMAX];
1135 int chaini = 0; // index into worklist
1136 Klass* chain; // scratch variable
1137 #define ADD_SUBCLASS_CHAIN(k) { \
1138 assert(chaini < CHAINMAX, "oob"); \
1139 chain = k->subklass(); \
1140 if (chain != NULL) chains[chaini++] = chain; }
1141
1142 // Look for non-abstract subclasses.
1143 // (Note: Interfaces do not have subclasses.)
1144 ADD_SUBCLASS_CHAIN(context_type);
1145
1146 // If it is an interface, search its direct implementors.
1147 // (Their subclasses are additional indirect implementors.
1148 // See InstanceKlass::add_implementor.)
1149 // (Note: nof_implementors is always zero for non-interfaces.)
1150 if (top_level_call) {
1151 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1152 if (nof_impls > 1) {
1153 // Avoid this case: *I.m > { A.m, C }; B.m > C
1154 // Here, I.m has 2 concrete implementations, but m appears unique
1155 // as A.m, because the search misses B.m when checking C.
1156 // The inherited method B.m was getting missed by the walker
1157 // when interface 'I' was the starting point.
1158 // %%% Until this is fixed more systematically, bail out.
1159 // (Old CHA had the same limitation.)
1160 return context_type;
1161 }
1162 if (nof_impls > 0) {
1163 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1164 assert(impl != NULL, "just checking");
1165 // If impl is the same as the context_type, then more than one
1166 // implementor has seen. No exact info in this case.
1167 if (impl == context_type) {
1168 return context_type; // report an inexact witness to this sad affair
1169 }
1170 if (do_counts)
1171 { NOT_PRODUCT(deps_find_witness_steps++); }
1172 if (is_participant(impl)) {
1173 if (!participants_hide_witnesses) {
1174 ADD_SUBCLASS_CHAIN(impl);
1175 }
1176 } else if (is_witness(impl) && !ignore_witness(impl)) {
1177 return impl;
1178 } else {
1179 ADD_SUBCLASS_CHAIN(impl);
1180 }
1181 }
1182 }
1183
1184 // Recursively process each non-trivial sibling chain.
1185 while (chaini > 0) {
1186 Klass* chain = chains[--chaini];
1187 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1188 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1189 if (is_participant(sub)) {
1190 if (participants_hide_witnesses) continue;
1191 // else fall through to process this guy's subclasses
1192 } else if (is_witness(sub) && !ignore_witness(sub)) {
1193 return sub;
1194 }
1195 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1196 // Fast path. (Partially disabled if VerifyDependencies.)
1197 ADD_SUBCLASS_CHAIN(sub);
1198 } else {
1199 // Worklist overflow. Do a recursive call. Should be rare.
1200 // The recursive call will have its own worklist, of course.
1201 // (Note that sub has already been tested, so that there is
1202 // no need for the recursive call to re-test. That's handy,
1203 // since the recursive call sees sub as the context_type.)
1204 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1205 Klass* witness = find_witness_anywhere(sub,
1206 participants_hide_witnesses,
1207 /*top_level_call=*/ false);
1208 if (witness != NULL) return witness;
1209 }
1210 }
1211 }
1212
1213 // No witness found. The dependency remains unbroken.
1214 return NULL;
1215 #undef ADD_SUBCLASS_CHAIN
1216 }
1217
1218
1219 bool Dependencies::is_concrete_klass(Klass* k) {
1220 if (k->is_abstract()) return false;
1221 // %%% We could treat classes which are concrete but
1222 // have not yet been instantiated as virtually abstract.
1223 // This would require a deoptimization barrier on first instantiation.
1224 //if (k->is_not_instantiated()) return false;
1225 return true;
1226 }
1227
1228 bool Dependencies::is_concrete_method(Method* m, Klass * k) {
1229 // NULL is not a concrete method,
1230 // statics are irrelevant to virtual call sites,
1231 // abstract methods are not concrete,
1232 // overpass (error) methods are not concrete if k is abstract
1233 //
1234 // note "true" is conservative answer --
1235 // overpass clause is false if k == NULL, implies return true if
1236 // answer depends on overpass clause.
1237 return ! ( m == NULL || m -> is_static() || m -> is_abstract() ||
1238 m->is_overpass() && k != NULL && k -> is_abstract() );
1239 }
1240
1241
1242 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1243 if (k->is_interface()) return NULL;
1244 if (k->has_finalizer()) return k;
1245 k = k->subklass();
1246 while (k != NULL) {
1247 Klass* result = find_finalizable_subclass(k);
1248 if (result != NULL) return result;
1249 k = k->next_sibling();
1250 }
1251 return NULL;
1252 }
1253
1254
1255 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1256 if (k->is_abstract()) return false;
1257 // We could also return false if k does not yet appear to be
1258 // instantiated, if the VM version supports this distinction also.
1259 //if (k->is_not_instantiated()) return false;
1260 return true;
1261 }
1262
1263 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1264 return k->has_finalizable_subclass();
1265 }
1266
1267
1268 // Any use of the contents (bytecodes) of a method must be
1269 // marked by an "evol_method" dependency, if those contents
1270 // can change. (Note: A method is always dependent on itself.)
1271 Klass* Dependencies::check_evol_method(Method* m) {
1272 assert(must_be_in_vm(), "raw oops here");
1273 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1274 // Or is there a now a breakpoint?
1275 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1276 if (m->is_old()
1277 || m->number_of_breakpoints() > 0) {
1278 return m->method_holder();
1279 } else {
1280 return NULL;
1281 }
1282 }
1283
1284 // This is a strong assertion: It is that the given type
1285 // has no subtypes whatever. It is most useful for
1286 // optimizing checks on reflected types or on array types.
1287 // (Checks on types which are derived from real instances
1288 // can be optimized more strongly than this, because we
1289 // know that the checked type comes from a concrete type,
1290 // and therefore we can disregard abstract types.)
1291 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1292 assert(must_be_in_vm(), "raw oops here");
1293 assert_locked_or_safepoint(Compile_lock);
1294 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1295 Klass* sub = ctx->subklass();
1296 if (sub != NULL) {
1297 return sub;
1298 } else if (ctx->nof_implementors() != 0) {
1299 // if it is an interface, it must be unimplemented
1300 // (if it is not an interface, nof_implementors is always zero)
1301 Klass* impl = ctx->implementor();
1302 assert(impl != NULL, "must be set");
1303 return impl;
1304 } else {
1305 return NULL;
1306 }
1307 }
1308
1309 // Test the assertion that conck is the only concrete subtype* of ctxk.
1310 // The type conck itself is allowed to have have further concrete subtypes.
1311 // This allows the compiler to narrow occurrences of ctxk by conck,
1312 // when dealing with the types of actual instances.
1313 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1314 Klass* conck,
1315 KlassDepChange* changes) {
1316 ClassHierarchyWalker wf(conck);
1317 return wf.find_witness_subtype(ctxk, changes);
1318 }
1319
1320 // If a non-concrete class has no concrete subtypes, it is not (yet)
1321 // instantiatable. This can allow the compiler to make some paths go
1322 // dead, if they are gated by a test of the type.
1323 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1324 KlassDepChange* changes) {
1325 // Find any concrete subtype, with no participants:
1326 ClassHierarchyWalker wf;
1327 return wf.find_witness_subtype(ctxk, changes);
1328 }
1329
1330
1331 // If a concrete class has no concrete subtypes, it can always be
1332 // exactly typed. This allows the use of a cheaper type test.
1333 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1334 KlassDepChange* changes) {
1335 // Find any concrete subtype, with only the ctxk as participant:
1336 ClassHierarchyWalker wf(ctxk);
1337 return wf.find_witness_subtype(ctxk, changes);
1338 }
1339
1340
1341 // Find the unique concrete proper subtype of ctxk, or NULL if there
1342 // is more than one concrete proper subtype. If there are no concrete
1343 // proper subtypes, return ctxk itself, whether it is concrete or not.
1344 // The returned subtype is allowed to have have further concrete subtypes.
1345 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1346 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1347 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1348 wf.record_witnesses(1); // Record one other witness when walking.
1349 Klass* wit = wf.find_witness_subtype(ctxk);
1350 if (wit != NULL) return NULL; // Too many witnesses.
1351 Klass* conck = wf.participant(0);
1352 if (conck == NULL) {
1353 #ifndef PRODUCT
1354 // Make sure the dependency mechanism will pass this discovery:
1355 if (VerifyDependencies) {
1356 // Turn off dependency tracing while actually testing deps.
1357 FlagSetting fs(TraceDependencies, false);
1358 if (!Dependencies::is_concrete_klass(ctxk)) {
1359 guarantee(NULL ==
1360 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1361 "verify dep.");
1362 } else {
1363 guarantee(NULL ==
1364 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1365 "verify dep.");
1366 }
1367 }
1368 #endif //PRODUCT
1369 return ctxk; // Return ctxk as a flag for "no subtypes".
1370 } else {
1371 #ifndef PRODUCT
1372 // Make sure the dependency mechanism will pass this discovery:
1373 if (VerifyDependencies) {
1374 // Turn off dependency tracing while actually testing deps.
1375 FlagSetting fs(TraceDependencies, false);
1376 if (!Dependencies::is_concrete_klass(ctxk)) {
1377 guarantee(NULL == (void *)
1378 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1379 "verify dep.");
1380 }
1381 }
1382 #endif //PRODUCT
1383 return conck;
1384 }
1385 }
1386
1387 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1388 // except possibly for further subtypes of k[12] themselves.
1389 // The context type must be abstract. The types k1 and k2 are themselves
1390 // allowed to have further concrete subtypes.
1391 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1392 Klass* ctxk,
1393 Klass* k1,
1394 Klass* k2,
1395 KlassDepChange* changes) {
1396 ClassHierarchyWalker wf;
1397 wf.add_participant(k1);
1398 wf.add_participant(k2);
1399 return wf.find_witness_subtype(ctxk, changes);
1400 }
1401
1402 // Search ctxk for concrete implementations. If there are klen or fewer,
1403 // pack them into the given array and return the number.
1404 // Otherwise, return -1, meaning the given array would overflow.
1405 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1406 // In this search, if ctxk is concrete, it will be reported alone.
1407 // For any type CC reported, no proper subtypes of CC will be reported.
1408 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1409 int klen,
1410 Klass* karray[]) {
1411 ClassHierarchyWalker wf;
1412 wf.record_witnesses(klen);
1413 Klass* wit = wf.find_witness_subtype(ctxk);
1414 if (wit != NULL) return -1; // Too many witnesses.
1415 int num = wf.num_participants();
1416 assert(num <= klen, "oob");
1417 // Pack the result array with the good news.
1418 for (int i = 0; i < num; i++)
1419 karray[i] = wf.participant(i);
1420 #ifndef PRODUCT
1421 // Make sure the dependency mechanism will pass this discovery:
1422 if (VerifyDependencies) {
1423 // Turn off dependency tracing while actually testing deps.
1424 FlagSetting fs(TraceDependencies, false);
1425 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1426 case -1: // ctxk was itself concrete
1427 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1428 break;
1429 case 0:
1430 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1431 "verify dep.");
1432 break;
1433 case 1:
1434 guarantee(NULL == (void *)
1435 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1436 "verify dep.");
1437 break;
1438 case 2:
1439 guarantee(NULL == (void *)
1440 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1441 karray[0],
1442 karray[1]),
1443 "verify dep.");
1444 break;
1445 default:
1446 ShouldNotReachHere(); // klen > 2 yet supported
1447 }
1448 }
1449 #endif //PRODUCT
1450 return num;
1451 }
1452
1453 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1454 // Otherwise, return a class that contains an interfering method.
1455 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1456 KlassDepChange* changes) {
1457 // Here is a missing optimization: If uniqm->is_final(),
1458 // we don't really need to search beneath it for overrides.
1459 // This is probably not important, since we don't use dependencies
1460 // to track final methods. (They can't be "definalized".)
1461 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1462 return wf.find_witness_definer(ctxk, changes);
1463 }
1464
1465 // Find the set of all non-abstract methods under ctxk that match m.
1466 // (The method m must be defined or inherited in ctxk.)
1467 // Include m itself in the set, unless it is abstract.
1468 // If this set has exactly one element, return that element.
1469 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1470 // Return NULL if m is marked old; must have been a redefined method.
1471 if (m->is_old()) {
1472 return NULL;
1473 }
1474 ClassHierarchyWalker wf(m);
1475 assert(wf.check_method_context(ctxk, m), "proper context");
1476 wf.record_witnesses(1);
1477 Klass* wit = wf.find_witness_definer(ctxk);
1478 if (wit != NULL) return NULL; // Too many witnesses.
1479 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1480 if (Dependencies::is_concrete_method(m, ctxk)) {
1481 if (fm == NULL) {
1482 // It turns out that m was always the only implementation.
1483 fm = m;
1484 } else if (fm != m) {
1485 // Two conflicting implementations after all.
1486 // (This can happen if m is inherited into ctxk and fm overrides it.)
1487 return NULL;
1488 }
1489 }
1490 #ifndef PRODUCT
1491 // Make sure the dependency mechanism will pass this discovery:
1492 if (VerifyDependencies && fm != NULL) {
1493 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1494 "verify dep.");
1495 }
1496 #endif //PRODUCT
1497 return fm;
1498 }
1499
1500 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1501 Method* m1,
1502 Method* m2,
1503 KlassDepChange* changes) {
1504 ClassHierarchyWalker wf(m1);
1505 wf.add_participant(m1->method_holder());
1506 wf.add_participant(m2->method_holder());
1507 return wf.find_witness_definer(ctxk, changes);
1508 }
1509
1510 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1511 Klass* search_at = ctxk;
1512 if (changes != NULL)
1513 search_at = changes->new_type(); // just look at the new bit
1514 return find_finalizable_subclass(search_at);
1515 }
1516
1517 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1518 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1519 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1520 if (changes == NULL) {
1521 // Validate all CallSites
1522 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1523 return call_site->klass(); // assertion failed
1524 } else {
1525 // Validate the given CallSite
1526 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1527 assert(method_handle != changes->method_handle(), "must be");
1528 return call_site->klass(); // assertion failed
1529 }
1530 }
1531 return NULL; // assertion still valid
1532 }
1533
1534
1535 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1536 if (witness != NULL) {
1537 if (TraceDependencies) {
1538 print_dependency(witness, /*verbose=*/ true);
1539 }
1540 // The following is a no-op unless logging is enabled:
1541 log_dependency(witness);
1542 }
1543 }
1544
1545
1546 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1547 assert_locked_or_safepoint(Compile_lock);
1548 Dependencies::check_valid_dependency_type(type());
1549
1550 Klass* witness = NULL;
1551 switch (type()) {
1552 case evol_method:
1553 witness = check_evol_method(method_argument(0));
1554 break;
1555 case leaf_type:
1556 witness = check_leaf_type(context_type());
1557 break;
1558 case abstract_with_unique_concrete_subtype:
1559 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1560 break;
1561 case abstract_with_no_concrete_subtype:
1562 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1563 break;
1564 case concrete_with_no_concrete_subtype:
1565 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1566 break;
1567 case unique_concrete_method:
1568 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1569 break;
1570 case abstract_with_exclusive_concrete_subtypes_2:
1571 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1572 break;
1573 case exclusive_concrete_methods_2:
1574 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1575 break;
1576 case no_finalizable_subclasses:
1577 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1578 break;
1579 default:
1580 witness = NULL;
1581 break;
1582 }
1583 trace_and_log_witness(witness);
1584 return witness;
1585 }
1586
1587
1588 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1589 assert_locked_or_safepoint(Compile_lock);
1590 Dependencies::check_valid_dependency_type(type());
1591
1592 Klass* witness = NULL;
1593 switch (type()) {
1594 case call_site_target_value:
1595 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1596 break;
1597 default:
1598 witness = NULL;
1599 break;
1600 }
1601 trace_and_log_witness(witness);
1602 return witness;
1603 }
1604
1605
1606 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1607 // Handle klass dependency
1608 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1609 return check_klass_dependency(changes.as_klass_change());
1610
1611 // Handle CallSite dependency
1612 if (changes.is_call_site_change())
1613 return check_call_site_dependency(changes.as_call_site_change());
1614
1615 // irrelevant dependency; skip it
1616 return NULL;
1617 }
1618
1619
1620 void DepChange::print() {
1621 int nsup = 0, nint = 0;
1622 for (ContextStream str(*this); str.next(); ) {
1623 Klass* k = str.klass();
1624 switch (str.change_type()) {
1625 case Change_new_type:
1626 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1627 break;
1628 case Change_new_sub:
1629 if (!WizardMode) {
1630 ++nsup;
1631 } else {
1632 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1633 }
1634 break;
1635 case Change_new_impl:
1636 if (!WizardMode) {
1637 ++nint;
1638 } else {
1639 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1640 }
1641 break;
1642 }
1643 }
1644 if (nsup + nint != 0) {
1645 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1646 }
1647 }
1648
1649 void DepChange::ContextStream::start() {
1650 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1651 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1652 _klass = new_type;
1653 _ti_base = NULL;
1654 _ti_index = 0;
1655 _ti_limit = 0;
1656 }
1657
1658 bool DepChange::ContextStream::next() {
1659 switch (_change_type) {
1660 case Start_Klass: // initial state; _klass is the new type
1661 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1662 _ti_index = 0;
1663 _change_type = Change_new_type;
1664 return true;
1665 case Change_new_type:
1666 // fall through:
1667 _change_type = Change_new_sub;
1668 case Change_new_sub:
1669 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1670 {
1671 _klass = InstanceKlass::cast(_klass)->super();
1672 if (_klass != NULL) {
1673 return true;
1674 }
1675 }
1676 // else set up _ti_limit and fall through:
1677 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1678 _change_type = Change_new_impl;
1679 case Change_new_impl:
1680 if (_ti_index < _ti_limit) {
1681 _klass = _ti_base->at(_ti_index++);
1682 return true;
1683 }
1684 // fall through:
1685 _change_type = NO_CHANGE; // iterator is exhausted
1686 case NO_CHANGE:
1687 break;
1688 default:
1689 ShouldNotReachHere();
1690 }
1691 return false;
1692 }
1693
1694 void KlassDepChange::initialize() {
1695 // entire transaction must be under this lock:
1696 assert_lock_strong(Compile_lock);
1697
1698 // Mark all dependee and all its superclasses
1699 // Mark transitive interfaces
1700 for (ContextStream str(*this); str.next(); ) {
1701 Klass* d = str.klass();
1702 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1703 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1704 }
1705 }
1706
1707 KlassDepChange::~KlassDepChange() {
1708 // Unmark all dependee and all its superclasses
1709 // Unmark transitive interfaces
1710 for (ContextStream str(*this); str.next(); ) {
1711 Klass* d = str.klass();
1712 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1713 }
1714 }
1715
1716 bool KlassDepChange::involves_context(Klass* k) {
1717 if (k == NULL || !k->oop_is_instance()) {
1718 return false;
1719 }
1720 InstanceKlass* ik = InstanceKlass::cast(k);
1721 bool is_contained = ik->is_marked_dependent();
1722 assert(is_contained == new_type()->is_subtype_of(k),
1723 "correct marking of potential context types");
1724 return is_contained;
1725 }
1726
1727 #ifndef PRODUCT
1728 void Dependencies::print_statistics() {
1729 if (deps_find_witness_print != 0) {
1730 // Call one final time, to flush out the data.
1731 deps_find_witness_print = -1;
1732 count_find_witness_calls();
1733 }
1734 }
1735 #endif