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 "runtime/thread.inline.hpp"
36 #include "utilities/copy.hpp"
37
38
39 #ifdef ASSERT
40 static bool must_be_in_vm() {
41 Thread* thread = Thread::current();
42 if (thread->is_Java_thread())
43 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
44 else
45 return true; //something like this: thread->is_VM_thread();
46 }
47 #endif //ASSERT
48
49 void Dependencies::initialize(ciEnv* env) {
50 Arena* arena = env->arena();
51 _oop_recorder = env->oop_recorder();
52 _log = env->log();
53 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
54 DEBUG_ONLY(_deps[end_marker] = NULL);
55 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
56 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
57 }
58 _content_bytes = NULL;
59 _size_in_bytes = (size_t)-1;
60
61 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
62 }
63
64 void Dependencies::assert_evol_method(ciMethod* m) {
65 assert_common_1(evol_method, m);
66 }
67
68 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
69 if (ctxk->is_array_klass()) {
70 // As a special case, support this assertion on an array type,
71 // which reduces to an assertion on its element type.
72 // Note that this cannot be done with assertions that
73 // relate to concreteness or abstractness.
74 ciType* elemt = ctxk->as_array_klass()->base_element_type();
75 if (!elemt->is_instance_klass()) return; // Ex: int[][]
76 ctxk = elemt->as_instance_klass();
77 //if (ctxk->is_final()) return; // Ex: String[][]
78 }
79 check_ctxk(ctxk);
80 assert_common_1(leaf_type, ctxk);
81 }
82
83 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
84 check_ctxk_abstract(ctxk);
85 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
86 }
87
88 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
89 check_ctxk_abstract(ctxk);
90 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
91 }
92
93 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
94 check_ctxk_concrete(ctxk);
95 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
96 }
97
98 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
99 check_ctxk(ctxk);
100 assert_common_2(unique_concrete_method, ctxk, uniqm);
101 }
102
103 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
104 check_ctxk(ctxk);
105 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
106 }
107
108 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
109 check_ctxk(ctxk);
110 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
111 }
112
113 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
114 check_ctxk(ctxk);
115 assert_common_1(no_finalizable_subclasses, ctxk);
116 }
117
118 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
119 check_ctxk(call_site->klass());
120 assert_common_2(call_site_target_value, call_site, method_handle);
121 }
122
123 // Helper function. If we are adding a new dep. under ctxk2,
124 // try to find an old dep. under a broader* ctxk1. If there is
125 //
126 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
127 int ctxk_i, ciKlass* ctxk2) {
128 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
129 if (ctxk2->is_subtype_of(ctxk1)) {
130 return true; // success, and no need to change
131 } else if (ctxk1->is_subtype_of(ctxk2)) {
132 // new context class fully subsumes previous one
133 deps->at_put(ctxk_i, ctxk2);
134 return true;
135 } else {
136 return false;
137 }
138 }
139
140 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
141 assert(dep_args(dept) == 1, "sanity");
142 log_dependency(dept, x);
143 GrowableArray<ciBaseObject*>* deps = _deps[dept];
144
145 // see if the same (or a similar) dep is already recorded
146 if (note_dep_seen(dept, x)) {
147 assert(deps->find(x) >= 0, "sanity");
148 } else {
149 deps->append(x);
150 }
151 }
152
153 void Dependencies::assert_common_2(DepType dept,
154 ciBaseObject* x0, ciBaseObject* x1) {
155 assert(dep_args(dept) == 2, "sanity");
156 log_dependency(dept, x0, x1);
157 GrowableArray<ciBaseObject*>* deps = _deps[dept];
158
159 // see if the same (or a similar) dep is already recorded
160 bool has_ctxk = has_explicit_context_arg(dept);
161 if (has_ctxk) {
162 assert(dep_context_arg(dept) == 0, "sanity");
163 if (note_dep_seen(dept, x1)) {
164 // look in this bucket for redundant assertions
165 const int stride = 2;
166 for (int i = deps->length(); (i -= stride) >= 0; ) {
167 ciBaseObject* y1 = deps->at(i+1);
168 if (x1 == y1) { // same subject; check the context
169 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
170 return;
171 }
172 }
173 }
174 }
175 } else {
176 assert(dep_implicit_context_arg(dept) == 0, "sanity");
177 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
178 // look in this bucket for redundant assertions
179 const int stride = 2;
180 for (int i = deps->length(); (i -= stride) >= 0; ) {
181 ciBaseObject* y0 = deps->at(i+0);
182 ciBaseObject* y1 = deps->at(i+1);
183 if (x0 == y0 && x1 == y1) {
184 return;
185 }
186 }
187 }
188 }
189
190 // append the assertion in the correct bucket:
191 deps->append(x0);
192 deps->append(x1);
193 }
194
195 void Dependencies::assert_common_3(DepType dept,
196 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
197 assert(dep_context_arg(dept) == 0, "sanity");
198 assert(dep_args(dept) == 3, "sanity");
199 log_dependency(dept, ctxk, x, x2);
200 GrowableArray<ciBaseObject*>* deps = _deps[dept];
201
202 // try to normalize an unordered pair:
203 bool swap = false;
204 switch (dept) {
205 case abstract_with_exclusive_concrete_subtypes_2:
206 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
207 break;
208 case exclusive_concrete_methods_2:
209 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
210 break;
211 }
212 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
213
214 // see if the same (or a similar) dep is already recorded
215 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
216 // look in this bucket for redundant assertions
217 const int stride = 3;
218 for (int i = deps->length(); (i -= stride) >= 0; ) {
219 ciBaseObject* y = deps->at(i+1);
220 ciBaseObject* y2 = deps->at(i+2);
221 if (x == y && x2 == y2) { // same subjects; check the context
222 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
223 return;
224 }
225 }
226 }
227 }
228 // append the assertion in the correct bucket:
229 deps->append(ctxk);
230 deps->append(x);
231 deps->append(x2);
232 }
233
234 /// Support for encoding dependencies into an nmethod:
235
236 void Dependencies::copy_to(nmethod* nm) {
237 address beg = nm->dependencies_begin();
238 address end = nm->dependencies_end();
239 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
240 Copy::disjoint_words((HeapWord*) content_bytes(),
241 (HeapWord*) beg,
242 size_in_bytes() / sizeof(HeapWord));
243 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
244 }
245
246 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
247 for (int i = 0; i < narg; i++) {
248 int diff = p1[i]->ident() - p2[i]->ident();
249 if (diff != 0) return diff;
250 }
251 return 0;
252 }
253 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
254 { return sort_dep(p1, p2, 1); }
255 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
256 { return sort_dep(p1, p2, 2); }
257 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
258 { return sort_dep(p1, p2, 3); }
259
260 void Dependencies::sort_all_deps() {
261 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
262 DepType dept = (DepType)deptv;
263 GrowableArray<ciBaseObject*>* deps = _deps[dept];
264 if (deps->length() <= 1) continue;
265 switch (dep_args(dept)) {
266 case 1: deps->sort(sort_dep_arg_1, 1); break;
267 case 2: deps->sort(sort_dep_arg_2, 2); break;
268 case 3: deps->sort(sort_dep_arg_3, 3); break;
269 default: ShouldNotReachHere();
270 }
271 }
272 }
273
274 size_t Dependencies::estimate_size_in_bytes() {
275 size_t est_size = 100;
276 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
277 DepType dept = (DepType)deptv;
278 GrowableArray<ciBaseObject*>* deps = _deps[dept];
279 est_size += deps->length()*2; // tags and argument(s)
280 }
281 return est_size;
282 }
283
284 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
285 switch (dept) {
286 case abstract_with_exclusive_concrete_subtypes_2:
287 return x->as_metadata()->as_klass();
288 case unique_concrete_method:
289 case exclusive_concrete_methods_2:
290 return x->as_metadata()->as_method()->holder();
291 }
292 return NULL; // let NULL be NULL
293 }
294
295 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
296 assert(must_be_in_vm(), "raw oops here");
297 switch (dept) {
298 case abstract_with_exclusive_concrete_subtypes_2:
299 assert(x->is_klass(), "sanity");
300 return (Klass*) x;
301 case unique_concrete_method:
302 case exclusive_concrete_methods_2:
303 assert(x->is_method(), "sanity");
304 return ((Method*)x)->method_holder();
305 }
306 return NULL; // let NULL be NULL
307 }
308
309 void Dependencies::encode_content_bytes() {
310 sort_all_deps();
311
312 // cast is safe, no deps can overflow INT_MAX
313 CompressedWriteStream bytes((int)estimate_size_in_bytes());
314
315 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
316 DepType dept = (DepType)deptv;
317 GrowableArray<ciBaseObject*>* deps = _deps[dept];
318 if (deps->length() == 0) continue;
319 int stride = dep_args(dept);
320 int ctxkj = dep_context_arg(dept); // -1 if no context arg
321 assert(stride > 0, "sanity");
322 for (int i = 0; i < deps->length(); i += stride) {
323 jbyte code_byte = (jbyte)dept;
324 int skipj = -1;
325 if (ctxkj >= 0 && ctxkj+1 < stride) {
326 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
327 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
328 if (ctxk == ctxk_encoded_as_null(dept, x)) {
329 skipj = ctxkj; // we win: maybe one less oop to keep track of
330 code_byte |= default_context_type_bit;
331 }
332 }
333 bytes.write_byte(code_byte);
334 for (int j = 0; j < stride; j++) {
335 if (j == skipj) continue;
336 ciBaseObject* v = deps->at(i+j);
337 int idx;
338 if (v->is_object()) {
339 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
340 } else {
341 ciMetadata* meta = v->as_metadata();
342 idx = _oop_recorder->find_index(meta->constant_encoding());
343 }
344 bytes.write_int(idx);
345 }
346 }
347 }
348
349 // write a sentinel byte to mark the end
350 bytes.write_byte(end_marker);
351
352 // round it out to a word boundary
353 while (bytes.position() % sizeof(HeapWord) != 0) {
354 bytes.write_byte(end_marker);
355 }
356
357 // check whether the dept byte encoding really works
358 assert((jbyte)default_context_type_bit != 0, "byte overflow");
359
360 _content_bytes = bytes.buffer();
361 _size_in_bytes = bytes.position();
362 }
363
364
365 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
366 "end_marker",
367 "evol_method",
368 "leaf_type",
369 "abstract_with_unique_concrete_subtype",
370 "abstract_with_no_concrete_subtype",
371 "concrete_with_no_concrete_subtype",
372 "unique_concrete_method",
373 "abstract_with_exclusive_concrete_subtypes_2",
374 "exclusive_concrete_methods_2",
375 "no_finalizable_subclasses",
376 "call_site_target_value"
377 };
378
379 int Dependencies::_dep_args[TYPE_LIMIT] = {
380 -1,// end_marker
381 1, // evol_method m
382 1, // leaf_type ctxk
383 2, // abstract_with_unique_concrete_subtype ctxk, k
384 1, // abstract_with_no_concrete_subtype ctxk
385 1, // concrete_with_no_concrete_subtype ctxk
386 2, // unique_concrete_method ctxk, m
387 3, // unique_concrete_subtypes_2 ctxk, k1, k2
388 3, // unique_concrete_methods_2 ctxk, m1, m2
389 1, // no_finalizable_subclasses ctxk
390 2 // call_site_target_value call_site, method_handle
391 };
392
393 const char* Dependencies::dep_name(Dependencies::DepType dept) {
394 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
395 return _dep_name[dept];
396 }
397
398 int Dependencies::dep_args(Dependencies::DepType dept) {
399 if (!dept_in_mask(dept, all_types)) return -1;
400 return _dep_args[dept];
401 }
402
403 void Dependencies::check_valid_dependency_type(DepType dept) {
404 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
405 }
406
407 // for the sake of the compiler log, print out current dependencies:
408 void Dependencies::log_all_dependencies() {
409 if (log() == NULL) return;
410 ciBaseObject* args[max_arg_count];
411 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
412 DepType dept = (DepType)deptv;
413 GrowableArray<ciBaseObject*>* deps = _deps[dept];
414 if (deps->length() == 0) continue;
415 int stride = dep_args(dept);
416 for (int i = 0; i < deps->length(); i += stride) {
417 for (int j = 0; j < stride; j++) {
418 // flush out the identities before printing
419 args[j] = deps->at(i+j);
420 }
421 write_dependency_to(log(), dept, stride, args);
422 }
423 }
424 }
425
426 void Dependencies::write_dependency_to(CompileLog* log,
427 DepType dept,
428 int nargs, DepArgument args[],
429 Klass* witness) {
430 if (log == NULL) {
431 return;
432 }
433 ciEnv* env = ciEnv::current();
434 ciBaseObject* ciargs[max_arg_count];
435 assert(nargs <= max_arg_count, "oob");
436 for (int j = 0; j < nargs; j++) {
437 if (args[j].is_oop()) {
438 ciargs[j] = env->get_object(args[j].oop_value());
439 } else {
440 ciargs[j] = env->get_metadata(args[j].metadata_value());
441 }
442 }
443 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
444 }
445
446 void Dependencies::write_dependency_to(CompileLog* log,
447 DepType dept,
448 int nargs, ciBaseObject* args[],
449 Klass* witness) {
450 if (log == NULL) return;
451 assert(nargs <= max_arg_count, "oob");
452 int argids[max_arg_count];
453 int ctxkj = dep_context_arg(dept); // -1 if no context arg
454 int j;
455 for (j = 0; j < nargs; j++) {
456 if (args[j]->is_object()) {
457 argids[j] = log->identify(args[j]->as_object());
458 } else {
459 argids[j] = log->identify(args[j]->as_metadata());
460 }
461 }
462 if (witness != NULL) {
463 log->begin_elem("dependency_failed");
464 } else {
465 log->begin_elem("dependency");
466 }
467 log->print(" type='%s'", dep_name(dept));
468 if (ctxkj >= 0) {
469 log->print(" ctxk='%d'", argids[ctxkj]);
470 }
471 // write remaining arguments, if any.
472 for (j = 0; j < nargs; j++) {
473 if (j == ctxkj) continue; // already logged
474 if (j == 1) {
475 log->print( " x='%d'", argids[j]);
476 } else {
477 log->print(" x%d='%d'", j, argids[j]);
478 }
479 }
480 if (witness != NULL) {
481 log->object("witness", witness);
482 log->stamp();
483 }
484 log->end_elem();
485 }
486
487 void Dependencies::write_dependency_to(xmlStream* xtty,
488 DepType dept,
489 int nargs, DepArgument args[],
490 Klass* witness) {
491 if (xtty == NULL) return;
492 ttyLocker ttyl;
493 int ctxkj = dep_context_arg(dept); // -1 if no context arg
494 if (witness != NULL) {
495 xtty->begin_elem("dependency_failed");
496 } else {
497 xtty->begin_elem("dependency");
498 }
499 xtty->print(" type='%s'", dep_name(dept));
500 if (ctxkj >= 0) {
501 xtty->object("ctxk", args[ctxkj].metadata_value());
502 }
503 // write remaining arguments, if any.
504 for (int j = 0; j < nargs; j++) {
505 if (j == ctxkj) continue; // already logged
506 if (j == 1) {
507 if (args[j].is_oop()) {
508 xtty->object("x", args[j].oop_value());
509 } else {
510 xtty->object("x", args[j].metadata_value());
511 }
512 } else {
513 char xn[10]; sprintf(xn, "x%d", j);
514 if (args[j].is_oop()) {
515 xtty->object(xn, args[j].oop_value());
516 } else {
517 xtty->object(xn, args[j].metadata_value());
518 }
519 }
520 }
521 if (witness != NULL) {
522 xtty->object("witness", witness);
523 xtty->stamp();
524 }
525 xtty->end_elem();
526 }
527
528 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[],
529 Klass* witness) {
530 ResourceMark rm;
531 ttyLocker ttyl; // keep the following output all in one block
532 tty->print_cr("%s of type %s",
533 (witness == NULL)? "Dependency": "Failed dependency",
534 dep_name(dept));
535 // print arguments
536 int ctxkj = dep_context_arg(dept); // -1 if no context arg
537 for (int j = 0; j < nargs; j++) {
538 DepArgument arg = args[j];
539 bool put_star = false;
540 if (arg.is_null()) continue;
541 const char* what;
542 if (j == ctxkj) {
543 assert(arg.is_metadata(), "must be");
544 what = "context";
545 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
546 } else if (arg.is_method()) {
547 what = "method ";
548 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
549 } else if (arg.is_klass()) {
550 what = "class ";
551 } else {
552 what = "object ";
553 }
554 tty->print(" %s = %s", what, (put_star? "*": ""));
555 if (arg.is_klass())
556 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
557 else if (arg.is_method())
558 ((Method*)arg.metadata_value())->print_value();
559 else
560 ShouldNotReachHere(); // Provide impl for this type.
561 tty->cr();
562 }
563 if (witness != NULL) {
564 bool put_star = !Dependencies::is_concrete_klass(witness);
565 tty->print_cr(" witness = %s%s",
566 (put_star? "*": ""),
567 witness->external_name());
568 }
569 }
570
571 void Dependencies::DepStream::log_dependency(Klass* witness) {
572 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
573 ResourceMark rm;
574 int nargs = argument_count();
575 DepArgument args[max_arg_count];
576 for (int j = 0; j < nargs; j++) {
577 if (type() == call_site_target_value) {
578 args[j] = argument_oop(j);
579 } else {
580 args[j] = argument(j);
581 }
582 }
583 if (_deps != NULL && _deps->log() != NULL) {
584 Dependencies::write_dependency_to(_deps->log(),
585 type(), nargs, args, witness);
586 } else {
587 Dependencies::write_dependency_to(xtty,
588 type(), nargs, args, witness);
589 }
590 }
591
592 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
593 int nargs = argument_count();
594 DepArgument args[max_arg_count];
595 for (int j = 0; j < nargs; j++) {
596 args[j] = argument(j);
597 }
598 Dependencies::print_dependency(type(), nargs, args, witness);
599 if (verbose) {
600 if (_code != NULL) {
601 tty->print(" code: ");
602 _code->print_value_on(tty);
603 tty->cr();
604 }
605 }
606 }
607
608
609 /// Dependency stream support (decodes dependencies from an nmethod):
610
611 #ifdef ASSERT
612 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
613 assert(must_be_in_vm(), "raw oops here");
614 _byte_limit = byte_limit;
615 _type = (DepType)(end_marker-1); // defeat "already at end" assert
616 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
617 }
618 #endif //ASSERT
619
620 bool Dependencies::DepStream::next() {
621 assert(_type != end_marker, "already at end");
622 if (_bytes.position() == 0 && _code != NULL
623 && _code->dependencies_size() == 0) {
624 // Method has no dependencies at all.
625 return false;
626 }
627 int code_byte = (_bytes.read_byte() & 0xFF);
628 if (code_byte == end_marker) {
629 DEBUG_ONLY(_type = end_marker);
630 return false;
631 } else {
632 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
633 code_byte -= ctxk_bit;
634 DepType dept = (DepType)code_byte;
635 _type = dept;
636 Dependencies::check_valid_dependency_type(dept);
637 int stride = _dep_args[dept];
638 assert(stride == dep_args(dept), "sanity");
639 int skipj = -1;
640 if (ctxk_bit != 0) {
641 skipj = 0; // currently the only context argument is at zero
642 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
643 }
644 for (int j = 0; j < stride; j++) {
645 _xi[j] = (j == skipj)? 0: _bytes.read_int();
646 }
647 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
648 return true;
649 }
650 }
651
652 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
653 Metadata* o = NULL;
654 if (_code != NULL) {
655 o = _code->metadata_at(i);
656 } else {
657 o = _deps->oop_recorder()->metadata_at(i);
658 }
659 return o;
660 }
661
662 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
663 return (_code != NULL)
664 ? _code->oop_at(i)
665 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
666 }
667
668 Metadata* Dependencies::DepStream::argument(int i) {
669 Metadata* result = recorded_metadata_at(argument_index(i));
670
671 if (result == NULL) { // Explicit context argument can be compressed
672 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
673 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
674 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
675 }
676 }
677
678 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
679 return result;
680 }
681
682 /**
683 * Returns a unique identifier for each dependency argument.
684 */
685 uintptr_t Dependencies::DepStream::get_identifier(int i) {
686 if (has_oop_argument()) {
687 return (uintptr_t)(oopDesc*)argument_oop(i);
688 } else {
689 return (uintptr_t)argument(i);
690 }
691 }
692
693 oop Dependencies::DepStream::argument_oop(int i) {
694 oop result = recorded_oop_at(argument_index(i));
695 assert(result == NULL || result->is_oop(), "must be");
696 return result;
697 }
698
699 Klass* Dependencies::DepStream::context_type() {
700 assert(must_be_in_vm(), "raw oops here");
701
702 // Most dependencies have an explicit context type argument.
703 {
704 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
705 if (ctxkj >= 0) {
706 Metadata* k = argument(ctxkj);
707 assert(k != NULL && k->is_klass(), "type check");
708 return (Klass*)k;
709 }
710 }
711
712 // Some dependencies are using the klass of the first object
713 // argument as implicit context type (e.g. call_site_target_value).
714 {
715 int ctxkj = dep_implicit_context_arg(type());
716 if (ctxkj >= 0) {
717 Klass* k = argument_oop(ctxkj)->klass();
718 assert(k != NULL && k->is_klass(), "type check");
719 return (Klass*) k;
720 }
721 }
722
723 // And some dependencies don't have a context type at all,
724 // e.g. evol_method.
725 return NULL;
726 }
727
728 // ----------------- DependencySignature --------------------------------------
729 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
730 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
731 return false;
732 }
733
734 for (int i = 0; i < s1.args_count(); i++) {
735 if (s1.arg(i) != s2.arg(i)) {
736 return false;
737 }
738 }
739 return true;
740 }
741
742 /// Checking dependencies:
743
744 // This hierarchy walker inspects subtypes of a given type,
745 // trying to find a "bad" class which breaks a dependency.
746 // Such a class is called a "witness" to the broken dependency.
747 // While searching around, we ignore "participants", which
748 // are already known to the dependency.
749 class ClassHierarchyWalker {
750 public:
751 enum { PARTICIPANT_LIMIT = 3 };
752
753 private:
754 // optional method descriptor to check for:
755 Symbol* _name;
756 Symbol* _signature;
757
758 // special classes which are not allowed to be witnesses:
759 Klass* _participants[PARTICIPANT_LIMIT+1];
760 int _num_participants;
761
762 // cache of method lookups
763 Method* _found_methods[PARTICIPANT_LIMIT+1];
764
765 // if non-zero, tells how many witnesses to convert to participants
766 int _record_witnesses;
767
768 void initialize(Klass* participant) {
769 _record_witnesses = 0;
770 _participants[0] = participant;
771 _found_methods[0] = NULL;
772 _num_participants = 0;
773 if (participant != NULL) {
774 // Terminating NULL.
775 _participants[1] = NULL;
776 _found_methods[1] = NULL;
777 _num_participants = 1;
778 }
779 }
780
781 void initialize_from_method(Method* m) {
782 assert(m != NULL && m->is_method(), "sanity");
783 _name = m->name();
784 _signature = m->signature();
785 }
786
787 public:
788 // The walker is initialized to recognize certain methods and/or types
789 // as friendly participants.
790 ClassHierarchyWalker(Klass* participant, Method* m) {
791 initialize_from_method(m);
792 initialize(participant);
793 }
794 ClassHierarchyWalker(Method* m) {
795 initialize_from_method(m);
796 initialize(NULL);
797 }
798 ClassHierarchyWalker(Klass* participant = NULL) {
799 _name = NULL;
800 _signature = NULL;
801 initialize(participant);
802 }
803
804 // This is common code for two searches: One for concrete subtypes,
805 // the other for concrete method implementations and overrides.
806 bool doing_subtype_search() {
807 return _name == NULL;
808 }
809
810 int num_participants() { return _num_participants; }
811 Klass* participant(int n) {
812 assert((uint)n <= (uint)_num_participants, "oob");
813 return _participants[n];
814 }
815
816 // Note: If n==num_participants, returns NULL.
817 Method* found_method(int n) {
818 assert((uint)n <= (uint)_num_participants, "oob");
819 Method* fm = _found_methods[n];
820 assert(n == _num_participants || fm != NULL, "proper usage");
821 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
822 return fm;
823 }
824
825 #ifdef ASSERT
826 // Assert that m is inherited into ctxk, without intervening overrides.
827 // (May return true even if this is not true, in corner cases where we punt.)
828 bool check_method_context(Klass* ctxk, Method* m) {
829 if (m->method_holder() == ctxk)
830 return true; // Quick win.
831 if (m->is_private())
832 return false; // Quick lose. Should not happen.
833 if (!(m->is_public() || m->is_protected()))
834 // The override story is complex when packages get involved.
835 return true; // Must punt the assertion to true.
836 Klass* k = ctxk;
837 Method* lm = k->lookup_method(m->name(), m->signature());
838 if (lm == NULL && k->oop_is_instance()) {
839 // It might be an interface method
840 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
841 m->signature());
842 }
843 if (lm == m)
844 // Method m is inherited into ctxk.
845 return true;
846 if (lm != NULL) {
847 if (!(lm->is_public() || lm->is_protected())) {
848 // Method is [package-]private, so the override story is complex.
849 return true; // Must punt the assertion to true.
850 }
851 if (lm->is_static()) {
852 // Static methods don't override non-static so punt
853 return true;
854 }
855 if ( !Dependencies::is_concrete_method(lm)
856 && !Dependencies::is_concrete_method(m)
857 && lm->method_holder()->is_subtype_of(m->method_holder()))
858 // Method m is overridden by lm, but both are non-concrete.
859 return true;
860 }
861 ResourceMark rm;
862 tty->print_cr("Dependency method not found in the associated context:");
863 tty->print_cr(" context = %s", ctxk->external_name());
864 tty->print( " method = "); m->print_short_name(tty); tty->cr();
865 if (lm != NULL) {
866 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
867 }
868 return false;
869 }
870 #endif
871
872 void add_participant(Klass* participant) {
873 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
874 int np = _num_participants++;
875 _participants[np] = participant;
876 _participants[np+1] = NULL;
877 _found_methods[np+1] = NULL;
878 }
879
880 void record_witnesses(int add) {
881 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
882 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
883 _record_witnesses = add;
884 }
885
886 bool is_witness(Klass* k) {
887 if (doing_subtype_search()) {
888 return Dependencies::is_concrete_klass(k);
889 } else {
890 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
891 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
892 _found_methods[_num_participants] = m;
893 // Note: If add_participant(k) is called,
894 // the method m will already be memoized for it.
895 return true;
896 }
897 }
898
899 bool is_participant(Klass* k) {
900 if (k == _participants[0]) {
901 return true;
902 } else if (_num_participants <= 1) {
903 return false;
904 } else {
905 return in_list(k, &_participants[1]);
906 }
907 }
908 bool ignore_witness(Klass* witness) {
909 if (_record_witnesses == 0) {
910 return false;
911 } else {
912 --_record_witnesses;
913 add_participant(witness);
914 return true;
915 }
916 }
917 static bool in_list(Klass* x, Klass** list) {
918 for (int i = 0; ; i++) {
919 Klass* y = list[i];
920 if (y == NULL) break;
921 if (y == x) return true;
922 }
923 return false; // not in list
924 }
925
926 private:
927 // the actual search method:
928 Klass* find_witness_anywhere(Klass* context_type,
929 bool participants_hide_witnesses,
930 bool top_level_call = true);
931 // the spot-checking version:
932 Klass* find_witness_in(KlassDepChange& changes,
933 Klass* context_type,
934 bool participants_hide_witnesses);
935 public:
936 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
937 assert(doing_subtype_search(), "must set up a subtype search");
938 // When looking for unexpected concrete types,
939 // do not look beneath expected ones.
940 const bool participants_hide_witnesses = true;
941 // CX > CC > C' is OK, even if C' is new.
942 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
943 if (changes != NULL) {
944 return find_witness_in(*changes, context_type, participants_hide_witnesses);
945 } else {
946 return find_witness_anywhere(context_type, participants_hide_witnesses);
947 }
948 }
949 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
950 assert(!doing_subtype_search(), "must set up a method definer search");
951 // When looking for unexpected concrete methods,
952 // look beneath expected ones, to see if there are overrides.
953 const bool participants_hide_witnesses = true;
954 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
955 if (changes != NULL) {
956 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
957 } else {
958 return find_witness_anywhere(context_type, !participants_hide_witnesses);
959 }
960 }
961 };
962
963 #ifndef PRODUCT
964 static int deps_find_witness_calls = 0;
965 static int deps_find_witness_steps = 0;
966 static int deps_find_witness_recursions = 0;
967 static int deps_find_witness_singles = 0;
968 static int deps_find_witness_print = 0; // set to -1 to force a final print
969 static bool count_find_witness_calls() {
970 if (TraceDependencies || LogCompilation) {
971 int pcount = deps_find_witness_print + 1;
972 bool final_stats = (pcount == 0);
973 bool initial_call = (pcount == 1);
974 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
975 if (pcount < 0) pcount = 1; // crude overflow protection
976 deps_find_witness_print = pcount;
977 if (VerifyDependencies && initial_call) {
978 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
979 }
980 if (occasional_print || final_stats) {
981 // Every now and then dump a little info about dependency searching.
982 if (xtty != NULL) {
983 ttyLocker ttyl;
984 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
985 deps_find_witness_calls,
986 deps_find_witness_steps,
987 deps_find_witness_recursions,
988 deps_find_witness_singles);
989 }
990 if (final_stats || (TraceDependencies && WizardMode)) {
991 ttyLocker ttyl;
992 tty->print_cr("Dependency check (find_witness) "
993 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
994 deps_find_witness_calls,
995 deps_find_witness_steps,
996 (double)deps_find_witness_steps / deps_find_witness_calls,
997 deps_find_witness_recursions,
998 deps_find_witness_singles);
999 }
1000 }
1001 return true;
1002 }
1003 return false;
1004 }
1005 #else
1006 #define count_find_witness_calls() (0)
1007 #endif //PRODUCT
1008
1009
1010 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1011 Klass* context_type,
1012 bool participants_hide_witnesses) {
1013 assert(changes.involves_context(context_type), "irrelevant dependency");
1014 Klass* new_type = changes.new_type();
1015
1016 (void)count_find_witness_calls();
1017 NOT_PRODUCT(deps_find_witness_singles++);
1018
1019 // Current thread must be in VM (not native mode, as in CI):
1020 assert(must_be_in_vm(), "raw oops here");
1021 // Must not move the class hierarchy during this check:
1022 assert_locked_or_safepoint(Compile_lock);
1023
1024 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1025 if (nof_impls > 1) {
1026 // Avoid this case: *I.m > { A.m, C }; B.m > C
1027 // %%% Until this is fixed more systematically, bail out.
1028 // See corresponding comment in find_witness_anywhere.
1029 return context_type;
1030 }
1031
1032 assert(!is_participant(new_type), "only old classes are participants");
1033 if (participants_hide_witnesses) {
1034 // If the new type is a subtype of a participant, we are done.
1035 for (int i = 0; i < num_participants(); i++) {
1036 Klass* part = participant(i);
1037 if (part == NULL) continue;
1038 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1039 "correct marking of participants, b/c new_type is unique");
1040 if (changes.involves_context(part)) {
1041 // new guy is protected from this check by previous participant
1042 return NULL;
1043 }
1044 }
1045 }
1046
1047 if (is_witness(new_type) &&
1048 !ignore_witness(new_type)) {
1049 return new_type;
1050 }
1051
1052 return NULL;
1053 }
1054
1055
1056 // Walk hierarchy under a context type, looking for unexpected types.
1057 // Do not report participant types, and recursively walk beneath
1058 // them only if participants_hide_witnesses is false.
1059 // If top_level_call is false, skip testing the context type,
1060 // because the caller has already considered it.
1061 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1062 bool participants_hide_witnesses,
1063 bool top_level_call) {
1064 // Current thread must be in VM (not native mode, as in CI):
1065 assert(must_be_in_vm(), "raw oops here");
1066 // Must not move the class hierarchy during this check:
1067 assert_locked_or_safepoint(Compile_lock);
1068
1069 bool do_counts = count_find_witness_calls();
1070
1071 // Check the root of the sub-hierarchy first.
1072 if (top_level_call) {
1073 if (do_counts) {
1074 NOT_PRODUCT(deps_find_witness_calls++);
1075 NOT_PRODUCT(deps_find_witness_steps++);
1076 }
1077 if (is_participant(context_type)) {
1078 if (participants_hide_witnesses) return NULL;
1079 // else fall through to search loop...
1080 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1081 // The context is an abstract class or interface, to start with.
1082 return context_type;
1083 }
1084 }
1085
1086 // Now we must check each implementor and each subclass.
1087 // Use a short worklist to avoid blowing the stack.
1088 // Each worklist entry is a *chain* of subklass siblings to process.
1089 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1090 Klass* chains[CHAINMAX];
1091 int chaini = 0; // index into worklist
1092 Klass* chain; // scratch variable
1093 #define ADD_SUBCLASS_CHAIN(k) { \
1094 assert(chaini < CHAINMAX, "oob"); \
1095 chain = InstanceKlass::cast(k)->subklass(); \
1096 if (chain != NULL) chains[chaini++] = chain; }
1097
1098 // Look for non-abstract subclasses.
1099 // (Note: Interfaces do not have subclasses.)
1100 ADD_SUBCLASS_CHAIN(context_type);
1101
1102 // If it is an interface, search its direct implementors.
1103 // (Their subclasses are additional indirect implementors.
1104 // See InstanceKlass::add_implementor.)
1105 // (Note: nof_implementors is always zero for non-interfaces.)
1106 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1107 if (nof_impls > 1) {
1108 // Avoid this case: *I.m > { A.m, C }; B.m > C
1109 // Here, I.m has 2 concrete implementations, but m appears unique
1110 // as A.m, because the search misses B.m when checking C.
1111 // The inherited method B.m was getting missed by the walker
1112 // when interface 'I' was the starting point.
1113 // %%% Until this is fixed more systematically, bail out.
1114 // (Old CHA had the same limitation.)
1115 return context_type;
1116 }
1117 if (nof_impls > 0) {
1118 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1119 assert(impl != NULL, "just checking");
1120 // If impl is the same as the context_type, then more than one
1121 // implementor has seen. No exact info in this case.
1122 if (impl == context_type) {
1123 return context_type; // report an inexact witness to this sad affair
1124 }
1125 if (do_counts)
1126 { NOT_PRODUCT(deps_find_witness_steps++); }
1127 if (is_participant(impl)) {
1128 if (!participants_hide_witnesses) {
1129 ADD_SUBCLASS_CHAIN(impl);
1130 }
1131 } else if (is_witness(impl) && !ignore_witness(impl)) {
1132 return impl;
1133 } else {
1134 ADD_SUBCLASS_CHAIN(impl);
1135 }
1136 }
1137
1138 // Recursively process each non-trivial sibling chain.
1139 while (chaini > 0) {
1140 Klass* chain = chains[--chaini];
1141 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1142 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1143 if (is_participant(sub)) {
1144 if (participants_hide_witnesses) continue;
1145 // else fall through to process this guy's subclasses
1146 } else if (is_witness(sub) && !ignore_witness(sub)) {
1147 return sub;
1148 }
1149 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1150 // Fast path. (Partially disabled if VerifyDependencies.)
1151 ADD_SUBCLASS_CHAIN(sub);
1152 } else {
1153 // Worklist overflow. Do a recursive call. Should be rare.
1154 // The recursive call will have its own worklist, of course.
1155 // (Note that sub has already been tested, so that there is
1156 // no need for the recursive call to re-test. That's handy,
1157 // since the recursive call sees sub as the context_type.)
1158 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1159 Klass* witness = find_witness_anywhere(sub,
1160 participants_hide_witnesses,
1161 /*top_level_call=*/ false);
1162 if (witness != NULL) return witness;
1163 }
1164 }
1165 }
1166
1167 // No witness found. The dependency remains unbroken.
1168 return NULL;
1169 #undef ADD_SUBCLASS_CHAIN
1170 }
1171
1172
1173 bool Dependencies::is_concrete_klass(Klass* k) {
1174 if (k->is_abstract()) return false;
1175 // %%% We could treat classes which are concrete but
1176 // have not yet been instantiated as virtually abstract.
1177 // This would require a deoptimization barrier on first instantiation.
1178 //if (k->is_not_instantiated()) return false;
1179 return true;
1180 }
1181
1182 bool Dependencies::is_concrete_method(Method* m) {
1183 // Statics are irrelevant to virtual call sites.
1184 if (m->is_static()) return false;
1185
1186 // We could also return false if m does not yet appear to be
1187 // executed, if the VM version supports this distinction also.
1188 // Default methods are considered "concrete" as well.
1189 return !m->is_abstract() &&
1190 !m->is_overpass(); // error functions aren't concrete
1191 }
1192
1193
1194 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1195 if (k->is_interface()) return NULL;
1196 if (k->has_finalizer()) return k;
1197 k = k->subklass();
1198 while (k != NULL) {
1199 Klass* result = find_finalizable_subclass(k);
1200 if (result != NULL) return result;
1201 k = k->next_sibling();
1202 }
1203 return NULL;
1204 }
1205
1206
1207 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1208 if (k->is_abstract()) return false;
1209 // We could also return false if k does not yet appear to be
1210 // instantiated, if the VM version supports this distinction also.
1211 //if (k->is_not_instantiated()) return false;
1212 return true;
1213 }
1214
1215 bool Dependencies::is_concrete_method(ciMethod* m) {
1216 // Statics are irrelevant to virtual call sites.
1217 if (m->is_static()) return false;
1218
1219 // We could also return false if m does not yet appear to be
1220 // executed, if the VM version supports this distinction also.
1221 return !m->is_abstract();
1222 }
1223
1224
1225 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1226 return k->has_finalizable_subclass();
1227 }
1228
1229
1230 // Any use of the contents (bytecodes) of a method must be
1231 // marked by an "evol_method" dependency, if those contents
1232 // can change. (Note: A method is always dependent on itself.)
1233 Klass* Dependencies::check_evol_method(Method* m) {
1234 assert(must_be_in_vm(), "raw oops here");
1235 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1236 // Or is there a now a breakpoint?
1237 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1238 if (m->is_old()
1239 || m->number_of_breakpoints() > 0) {
1240 return m->method_holder();
1241 } else {
1242 return NULL;
1243 }
1244 }
1245
1246 // This is a strong assertion: It is that the given type
1247 // has no subtypes whatever. It is most useful for
1248 // optimizing checks on reflected types or on array types.
1249 // (Checks on types which are derived from real instances
1250 // can be optimized more strongly than this, because we
1251 // know that the checked type comes from a concrete type,
1252 // and therefore we can disregard abstract types.)
1253 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1254 assert(must_be_in_vm(), "raw oops here");
1255 assert_locked_or_safepoint(Compile_lock);
1256 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1257 Klass* sub = ctx->subklass();
1258 if (sub != NULL) {
1259 return sub;
1260 } else if (ctx->nof_implementors() != 0) {
1261 // if it is an interface, it must be unimplemented
1262 // (if it is not an interface, nof_implementors is always zero)
1263 Klass* impl = ctx->implementor();
1264 assert(impl != NULL, "must be set");
1265 return impl;
1266 } else {
1267 return NULL;
1268 }
1269 }
1270
1271 // Test the assertion that conck is the only concrete subtype* of ctxk.
1272 // The type conck itself is allowed to have have further concrete subtypes.
1273 // This allows the compiler to narrow occurrences of ctxk by conck,
1274 // when dealing with the types of actual instances.
1275 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1276 Klass* conck,
1277 KlassDepChange* changes) {
1278 ClassHierarchyWalker wf(conck);
1279 return wf.find_witness_subtype(ctxk, changes);
1280 }
1281
1282 // If a non-concrete class has no concrete subtypes, it is not (yet)
1283 // instantiatable. This can allow the compiler to make some paths go
1284 // dead, if they are gated by a test of the type.
1285 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1286 KlassDepChange* changes) {
1287 // Find any concrete subtype, with no participants:
1288 ClassHierarchyWalker wf;
1289 return wf.find_witness_subtype(ctxk, changes);
1290 }
1291
1292
1293 // If a concrete class has no concrete subtypes, it can always be
1294 // exactly typed. This allows the use of a cheaper type test.
1295 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1296 KlassDepChange* changes) {
1297 // Find any concrete subtype, with only the ctxk as participant:
1298 ClassHierarchyWalker wf(ctxk);
1299 return wf.find_witness_subtype(ctxk, changes);
1300 }
1301
1302
1303 // Find the unique concrete proper subtype of ctxk, or NULL if there
1304 // is more than one concrete proper subtype. If there are no concrete
1305 // proper subtypes, return ctxk itself, whether it is concrete or not.
1306 // The returned subtype is allowed to have have further concrete subtypes.
1307 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1308 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1309 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1310 wf.record_witnesses(1); // Record one other witness when walking.
1311 Klass* wit = wf.find_witness_subtype(ctxk);
1312 if (wit != NULL) return NULL; // Too many witnesses.
1313 Klass* conck = wf.participant(0);
1314 if (conck == NULL) {
1315 #ifndef PRODUCT
1316 // Make sure the dependency mechanism will pass this discovery:
1317 if (VerifyDependencies) {
1318 // Turn off dependency tracing while actually testing deps.
1319 FlagSetting fs(TraceDependencies, false);
1320 if (!Dependencies::is_concrete_klass(ctxk)) {
1321 guarantee(NULL ==
1322 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1323 "verify dep.");
1324 } else {
1325 guarantee(NULL ==
1326 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1327 "verify dep.");
1328 }
1329 }
1330 #endif //PRODUCT
1331 return ctxk; // Return ctxk as a flag for "no subtypes".
1332 } else {
1333 #ifndef PRODUCT
1334 // Make sure the dependency mechanism will pass this discovery:
1335 if (VerifyDependencies) {
1336 // Turn off dependency tracing while actually testing deps.
1337 FlagSetting fs(TraceDependencies, false);
1338 if (!Dependencies::is_concrete_klass(ctxk)) {
1339 guarantee(NULL == (void *)
1340 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1341 "verify dep.");
1342 }
1343 }
1344 #endif //PRODUCT
1345 return conck;
1346 }
1347 }
1348
1349 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1350 // except possibly for further subtypes of k[12] themselves.
1351 // The context type must be abstract. The types k1 and k2 are themselves
1352 // allowed to have further concrete subtypes.
1353 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1354 Klass* ctxk,
1355 Klass* k1,
1356 Klass* k2,
1357 KlassDepChange* changes) {
1358 ClassHierarchyWalker wf;
1359 wf.add_participant(k1);
1360 wf.add_participant(k2);
1361 return wf.find_witness_subtype(ctxk, changes);
1362 }
1363
1364 // Search ctxk for concrete implementations. If there are klen or fewer,
1365 // pack them into the given array and return the number.
1366 // Otherwise, return -1, meaning the given array would overflow.
1367 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1368 // In this search, if ctxk is concrete, it will be reported alone.
1369 // For any type CC reported, no proper subtypes of CC will be reported.
1370 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1371 int klen,
1372 Klass* karray[]) {
1373 ClassHierarchyWalker wf;
1374 wf.record_witnesses(klen);
1375 Klass* wit = wf.find_witness_subtype(ctxk);
1376 if (wit != NULL) return -1; // Too many witnesses.
1377 int num = wf.num_participants();
1378 assert(num <= klen, "oob");
1379 // Pack the result array with the good news.
1380 for (int i = 0; i < num; i++)
1381 karray[i] = wf.participant(i);
1382 #ifndef PRODUCT
1383 // Make sure the dependency mechanism will pass this discovery:
1384 if (VerifyDependencies) {
1385 // Turn off dependency tracing while actually testing deps.
1386 FlagSetting fs(TraceDependencies, false);
1387 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1388 case -1: // ctxk was itself concrete
1389 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1390 break;
1391 case 0:
1392 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1393 "verify dep.");
1394 break;
1395 case 1:
1396 guarantee(NULL == (void *)
1397 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1398 "verify dep.");
1399 break;
1400 case 2:
1401 guarantee(NULL == (void *)
1402 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1403 karray[0],
1404 karray[1]),
1405 "verify dep.");
1406 break;
1407 default:
1408 ShouldNotReachHere(); // klen > 2 yet supported
1409 }
1410 }
1411 #endif //PRODUCT
1412 return num;
1413 }
1414
1415 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1416 // Otherwise, return a class that contains an interfering method.
1417 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1418 KlassDepChange* changes) {
1419 // Here is a missing optimization: If uniqm->is_final(),
1420 // we don't really need to search beneath it for overrides.
1421 // This is probably not important, since we don't use dependencies
1422 // to track final methods. (They can't be "definalized".)
1423 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1424 return wf.find_witness_definer(ctxk, changes);
1425 }
1426
1427 // Find the set of all non-abstract methods under ctxk that match m.
1428 // (The method m must be defined or inherited in ctxk.)
1429 // Include m itself in the set, unless it is abstract.
1430 // If this set has exactly one element, return that element.
1431 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1432 // Return NULL if m is marked old; must have been a redefined method.
1433 if (m->is_old()) {
1434 return NULL;
1435 }
1436 ClassHierarchyWalker wf(m);
1437 assert(wf.check_method_context(ctxk, m), "proper context");
1438 wf.record_witnesses(1);
1439 Klass* wit = wf.find_witness_definer(ctxk);
1440 if (wit != NULL) return NULL; // Too many witnesses.
1441 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1442 if (Dependencies::is_concrete_method(m)) {
1443 if (fm == NULL) {
1444 // It turns out that m was always the only implementation.
1445 fm = m;
1446 } else if (fm != m) {
1447 // Two conflicting implementations after all.
1448 // (This can happen if m is inherited into ctxk and fm overrides it.)
1449 return NULL;
1450 }
1451 }
1452 #ifndef PRODUCT
1453 // Make sure the dependency mechanism will pass this discovery:
1454 if (VerifyDependencies && fm != NULL) {
1455 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1456 "verify dep.");
1457 }
1458 #endif //PRODUCT
1459 return fm;
1460 }
1461
1462 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1463 Method* m1,
1464 Method* m2,
1465 KlassDepChange* changes) {
1466 ClassHierarchyWalker wf(m1);
1467 wf.add_participant(m1->method_holder());
1468 wf.add_participant(m2->method_holder());
1469 return wf.find_witness_definer(ctxk, changes);
1470 }
1471
1472 // Find the set of all non-abstract methods under ctxk that match m[0].
1473 // (The method m[0] must be defined or inherited in ctxk.)
1474 // Include m itself in the set, unless it is abstract.
1475 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1476 // (The length may be zero if no concrete methods are found anywhere.)
1477 // If there are too many concrete methods to fit in marray, return -1.
1478 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1479 int mlen,
1480 Method* marray[]) {
1481 Method* m0 = marray[0];
1482 ClassHierarchyWalker wf(m0);
1483 assert(wf.check_method_context(ctxk, m0), "proper context");
1484 wf.record_witnesses(mlen);
1485 bool participants_hide_witnesses = true;
1486 Klass* wit = wf.find_witness_definer(ctxk);
1487 if (wit != NULL) return -1; // Too many witnesses.
1488 int num = wf.num_participants();
1489 assert(num <= mlen, "oob");
1490 // Keep track of whether m is also part of the result set.
1491 int mfill = 0;
1492 assert(marray[mfill] == m0, "sanity");
1493 if (Dependencies::is_concrete_method(m0))
1494 mfill++; // keep m0 as marray[0], the first result
1495 for (int i = 0; i < num; i++) {
1496 Method* fm = wf.found_method(i);
1497 if (fm == m0) continue; // Already put this guy in the list.
1498 if (mfill == mlen) {
1499 return -1; // Oops. Too many methods after all!
1500 }
1501 marray[mfill++] = fm;
1502 }
1503 #ifndef PRODUCT
1504 // Make sure the dependency mechanism will pass this discovery:
1505 if (VerifyDependencies) {
1506 // Turn off dependency tracing while actually testing deps.
1507 FlagSetting fs(TraceDependencies, false);
1508 switch (mfill) {
1509 case 1:
1510 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1511 "verify dep.");
1512 break;
1513 case 2:
1514 guarantee(NULL == (void *)
1515 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1516 "verify dep.");
1517 break;
1518 default:
1519 ShouldNotReachHere(); // mlen > 2 yet supported
1520 }
1521 }
1522 #endif //PRODUCT
1523 return mfill;
1524 }
1525
1526
1527 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1528 Klass* search_at = ctxk;
1529 if (changes != NULL)
1530 search_at = changes->new_type(); // just look at the new bit
1531 return find_finalizable_subclass(search_at);
1532 }
1533
1534
1535 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1536 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1537 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1538 if (changes == NULL) {
1539 // Validate all CallSites
1540 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1541 return call_site->klass(); // assertion failed
1542 } else {
1543 // Validate the given CallSite
1544 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1545 assert(method_handle != changes->method_handle(), "must be");
1546 return call_site->klass(); // assertion failed
1547 }
1548 }
1549 return NULL; // assertion still valid
1550 }
1551
1552
1553 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1554 if (witness != NULL) {
1555 if (TraceDependencies) {
1556 print_dependency(witness, /*verbose=*/ true);
1557 }
1558 // The following is a no-op unless logging is enabled:
1559 log_dependency(witness);
1560 }
1561 }
1562
1563
1564 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1565 assert_locked_or_safepoint(Compile_lock);
1566 Dependencies::check_valid_dependency_type(type());
1567
1568 Klass* witness = NULL;
1569 switch (type()) {
1570 case evol_method:
1571 witness = check_evol_method(method_argument(0));
1572 break;
1573 case leaf_type:
1574 witness = check_leaf_type(context_type());
1575 break;
1576 case abstract_with_unique_concrete_subtype:
1577 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1578 break;
1579 case abstract_with_no_concrete_subtype:
1580 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1581 break;
1582 case concrete_with_no_concrete_subtype:
1583 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1584 break;
1585 case unique_concrete_method:
1586 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1587 break;
1588 case abstract_with_exclusive_concrete_subtypes_2:
1589 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1590 break;
1591 case exclusive_concrete_methods_2:
1592 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1593 break;
1594 case no_finalizable_subclasses:
1595 witness = check_has_no_finalizable_subclasses(context_type(), 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::check_call_site_dependency(CallSiteDepChange* changes) {
1607 assert_locked_or_safepoint(Compile_lock);
1608 Dependencies::check_valid_dependency_type(type());
1609
1610 Klass* witness = NULL;
1611 switch (type()) {
1612 case call_site_target_value:
1613 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1614 break;
1615 default:
1616 witness = NULL;
1617 break;
1618 }
1619 trace_and_log_witness(witness);
1620 return witness;
1621 }
1622
1623
1624 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1625 // Handle klass dependency
1626 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1627 return check_klass_dependency(changes.as_klass_change());
1628
1629 // Handle CallSite dependency
1630 if (changes.is_call_site_change())
1631 return check_call_site_dependency(changes.as_call_site_change());
1632
1633 // irrelevant dependency; skip it
1634 return NULL;
1635 }
1636
1637
1638 void DepChange::print() {
1639 int nsup = 0, nint = 0;
1640 for (ContextStream str(*this); str.next(); ) {
1641 Klass* k = str.klass();
1642 switch (str.change_type()) {
1643 case Change_new_type:
1644 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1645 break;
1646 case Change_new_sub:
1647 if (!WizardMode) {
1648 ++nsup;
1649 } else {
1650 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1651 }
1652 break;
1653 case Change_new_impl:
1654 if (!WizardMode) {
1655 ++nint;
1656 } else {
1657 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1658 }
1659 break;
1660 }
1661 }
1662 if (nsup + nint != 0) {
1663 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1664 }
1665 }
1666
1667 void DepChange::ContextStream::start() {
1668 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1669 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1670 _klass = new_type;
1671 _ti_base = NULL;
1672 _ti_index = 0;
1673 _ti_limit = 0;
1674 }
1675
1676 bool DepChange::ContextStream::next() {
1677 switch (_change_type) {
1678 case Start_Klass: // initial state; _klass is the new type
1679 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1680 _ti_index = 0;
1681 _change_type = Change_new_type;
1682 return true;
1683 case Change_new_type:
1684 // fall through:
1685 _change_type = Change_new_sub;
1686 case Change_new_sub:
1687 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1688 {
1689 _klass = InstanceKlass::cast(_klass)->super();
1690 if (_klass != NULL) {
1691 return true;
1692 }
1693 }
1694 // else set up _ti_limit and fall through:
1695 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1696 _change_type = Change_new_impl;
1697 case Change_new_impl:
1698 if (_ti_index < _ti_limit) {
1699 _klass = _ti_base->at(_ti_index++);
1700 return true;
1701 }
1702 // fall through:
1703 _change_type = NO_CHANGE; // iterator is exhausted
1704 case NO_CHANGE:
1705 break;
1706 default:
1707 ShouldNotReachHere();
1708 }
1709 return false;
1710 }
1711
1712 void KlassDepChange::initialize() {
1713 // entire transaction must be under this lock:
1714 assert_lock_strong(Compile_lock);
1715
1716 // Mark all dependee and all its superclasses
1717 // Mark transitive interfaces
1718 for (ContextStream str(*this); str.next(); ) {
1719 Klass* d = str.klass();
1720 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1721 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1722 }
1723 }
1724
1725 KlassDepChange::~KlassDepChange() {
1726 // Unmark all dependee and all its superclasses
1727 // Unmark transitive interfaces
1728 for (ContextStream str(*this); str.next(); ) {
1729 Klass* d = str.klass();
1730 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1731 }
1732 }
1733
1734 bool KlassDepChange::involves_context(Klass* k) {
1735 if (k == NULL || !k->oop_is_instance()) {
1736 return false;
1737 }
1738 InstanceKlass* ik = InstanceKlass::cast(k);
1739 bool is_contained = ik->is_marked_dependent();
1740 assert(is_contained == new_type()->is_subtype_of(k),
1741 "correct marking of potential context types");
1742 return is_contained;
1743 }
1744
1745 #ifndef PRODUCT
1746 void Dependencies::print_statistics() {
1747 if (deps_find_witness_print != 0) {
1748 // Call one final time, to flush out the data.
1749 deps_find_witness_print = -1;
1750 count_find_witness_calls();
1751 }
1752 }
1753 #endif