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 "oops/objArrayKlass.hpp"
34 #include "runtime/handles.hpp"
35 #include "runtime/handles.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<DepValue>(arena, 10, 0, DepValue());
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(Method* m) {
65 assert_common_1(evol_method, DepValue(_oop_recorder, m));
66 }
67
68 void Dependencies::assert_leaf_type(Klass* ctxk) {
69 if (ctxk->oop_is_array()) {
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 BasicType elemt = ArrayKlass::cast(ctxk)->element_type();
75 if (is_java_primitive(elemt)) return; // Ex: int[][]
76 ctxk = ObjArrayKlass::cast(ctxk)->bottom_klass();
77 //if (ctxk->is_final()) return; // Ex: String[][]
78 }
79 check_ctxk(ctxk);
80 assert_common_1(leaf_type, DepValue(_oop_recorder, ctxk));
81 }
82
83 void Dependencies::assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck) {
84 check_ctxk_abstract(ctxk);
85 DepValue ctxk_dv(_oop_recorder, ctxk);
86 assert_common_2(abstract_with_unique_concrete_subtype, ctxk_dv, DepValue(_oop_recorder, conck, &ctxk_dv));
87 }
88
89 void Dependencies::assert_abstract_with_no_concrete_subtype(Klass* ctxk) {
90 check_ctxk_abstract(ctxk);
91 assert_common_1(abstract_with_no_concrete_subtype, DepValue(_oop_recorder, ctxk));
92 }
93
94 void Dependencies::assert_concrete_with_no_concrete_subtype(Klass* ctxk) {
95 check_ctxk_concrete(ctxk);
96 assert_common_1(concrete_with_no_concrete_subtype, DepValue(_oop_recorder, ctxk));
97 }
98
99 void Dependencies::assert_unique_concrete_method(Klass* ctxk, Method* uniqm) {
100 check_ctxk(ctxk);
101 assert_common_2(unique_concrete_method, DepValue(_oop_recorder, ctxk), DepValue(_oop_recorder, uniqm));
102 }
103
104 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2) {
105 check_ctxk(ctxk);
106 DepValue k1_dv(_oop_recorder, k1);
107 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1_dv, DepValue(_oop_recorder, k2, &k1_dv));
108 }
109
110 void Dependencies::assert_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2) {
111 check_ctxk(ctxk);
112 DepValue m1_dv(_oop_recorder, m1);
113 assert_common_3(exclusive_concrete_methods_2, ctxk, m1_dv, DepValue(_oop_recorder, m2, &m1_dv));
114 }
115
116 void Dependencies::assert_has_no_finalizable_subclasses(Klass* ctxk) {
117 check_ctxk(ctxk);
118 assert_common_1(no_finalizable_subclasses, DepValue(_oop_recorder, ctxk));
119 }
120
121 void Dependencies::assert_call_site_target_value(jobject call_site, jobject method_handle) {
122 Klass* ctxk = JNIHandles::resolve(call_site)->klass();
123 check_ctxk(ctxk);
124 assert_common_2(call_site_target_value, DepValue(_oop_recorder, call_site), DepValue(_oop_recorder, method_handle));
125 }
126
127 // Helper function. If we are adding a new dep. under ctxk2,
128 // try to find an old dep. under a broader* ctxk1. If there is
129 //
130 bool Dependencies::maybe_merge_ctxk(GrowableArray<DepValue>* deps,
131 int ctxk_i, Klass* ctxk2) {
132 Klass* ctxk1 = deps->at(ctxk_i).as_klass(_oop_recorder);
133 if (ctxk2->is_subtype_of(ctxk1)) {
134 return true; // success, and no need to change
135 } else if (ctxk1->is_subtype_of(ctxk2)) {
136 // new context class fully subsumes previous one
137 deps->at_put(ctxk_i, DepValue(_oop_recorder, ctxk2));
138 return true;
139 } else {
140 return false;
141 }
142 }
143
144 void Dependencies::assert_common_1(DepType dept, DepValue x) {
145 assert(dep_args(dept) == 1, "sanity");
146 log_dependency(dept, x);
147 GrowableArray<DepValue>* deps = _deps[dept];
148
149 // see if the same (or a similar) dep is already recorded
150 if (note_dep_seen(dept, x)) {
151 assert(deps->find(x) >= 0, "sanity");
152 } else {
153 deps->append(x);
154 }
155 }
156
157 void Dependencies::assert_common_2(DepType dept,
158 DepValue x0, DepValue x1) {
159 assert(dep_args(dept) == 2, "sanity");
160 log_dependency(dept, x0, x1);
161 GrowableArray<DepValue>* deps = _deps[dept];
162
163 // see if the same (or a similar) dep is already recorded
164 bool has_ctxk = has_explicit_context_arg(dept);
165 if (has_ctxk) {
166 assert(dep_context_arg(dept) == 0, "sanity");
167 if (note_dep_seen(dept, x1)) {
168 // look in this bucket for redundant assertions
169 const int stride = 2;
170 for (int i = deps->length(); (i -= stride) >= 0; ) {
171 DepValue y1 = deps->at(i+1);
172 if (x1 == y1) { // same subject; check the context
173 if (maybe_merge_ctxk(deps, i+0, x0.as_klass(_oop_recorder))) {
174 return;
175 }
176 }
177 }
178 }
179 } else {
180 assert(dep_implicit_context_arg(dept) == 0, "sanity");
181 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
182 // look in this bucket for redundant assertions
183 const int stride = 2;
184 for (int i = deps->length(); (i -= stride) >= 0; ) {
185 DepValue y0 = deps->at(i+0);
186 DepValue y1 = deps->at(i+1);
187 if (x0 == y0 && x1 == y1) {
188 return;
189 }
190 }
191 }
192 }
193
194 // append the assertion in the correct bucket:
195 deps->append(x0);
196 deps->append(x1);
197 }
198
199 void Dependencies::assert_common_3(DepType dept,
200 Klass* ctxk, DepValue x, DepValue x2) {
201 assert(dep_context_arg(dept) == 0, "sanity");
202 assert(dep_args(dept) == 3, "sanity");
203 log_dependency(dept, DepValue(_oop_recorder, ctxk), x, x2);
204 GrowableArray<DepValue>* deps = _deps[dept];
205
206 // try to normalize an unordered pair:
207 bool swap = false;
208 switch (dept) {
209 case abstract_with_exclusive_concrete_subtypes_2:
210 swap = (x.index() > x2.index() && x.as_klass(_oop_recorder) != ctxk);
211 break;
212 case exclusive_concrete_methods_2:
213 swap = (x.index() > x2.index() && x.as_method(_oop_recorder)->method_holder() != ctxk);
214 break;
215 }
216 if (swap) { DepValue t = x; x = x2; x2 = t; }
217
218 // see if the same (or a similar) dep is already recorded
219 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
220 // look in this bucket for redundant assertions
221 const int stride = 3;
222 for (int i = deps->length(); (i -= stride) >= 0; ) {
223 DepValue y = deps->at(i+1);
224 DepValue y2 = deps->at(i+2);
225 if (x == y && x2 == y2) { // same subjects; check the context
226 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
227 return;
228 }
229 }
230 }
231 }
232 // append the assertion in the correct bucket:
233 deps->append(DepValue(_oop_recorder, ctxk));
234 deps->append(x);
235 deps->append(x2);
236 }
237
238 /// Support for encoding dependencies into an nmethod:
239
240 void Dependencies::copy_to(nmethod* nm) {
241 address beg = nm->dependencies_begin();
242 address end = nm->dependencies_end();
243 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
244 Copy::disjoint_words((HeapWord*) content_bytes(),
245 (HeapWord*) beg,
246 size_in_bytes() / sizeof(HeapWord));
247 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
248 }
249
250 static int sort_dep(Dependencies::DepValue* p1, Dependencies::DepValue* p2, int narg) {
251 for (int i = 0; i < narg; i++) {
252 int diff = p1[i].sort_key() - p2[i].sort_key();
253 if (diff != 0) return diff;
254 }
255 return 0;
256 }
257 static int sort_dep_arg_1(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
258 { return sort_dep(p1, p2, 1); }
259 static int sort_dep_arg_2(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
260 { return sort_dep(p1, p2, 2); }
261 static int sort_dep_arg_3(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
262 { return sort_dep(p1, p2, 3); }
263
264 void Dependencies::sort_all_deps() {
265 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
266 DepType dept = (DepType)deptv;
267 GrowableArray<DepValue>* deps = _deps[dept];
268 if (deps->length() <= 1) continue;
269 switch (dep_args(dept)) {
270 case 1: deps->sort(sort_dep_arg_1, 1); break;
271 case 2: deps->sort(sort_dep_arg_2, 2); break;
272 case 3: deps->sort(sort_dep_arg_3, 3); break;
273 default: ShouldNotReachHere();
274 }
275 }
276 }
277
278 size_t Dependencies::estimate_size_in_bytes() {
279 size_t est_size = 100;
280 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
281 DepType dept = (DepType)deptv;
282 GrowableArray<DepValue>* deps = _deps[dept];
283 est_size += deps->length()*2; // tags and argument(s)
284 }
285 return est_size;
286 }
287
288 Klass* Dependencies::ctxk_encoded_as_null(OopRecorder* oop_recorder, DepType dept, DepValue x) {
289 switch (dept) {
290 case abstract_with_exclusive_concrete_subtypes_2:
291 return x.as_klass(oop_recorder);
292 case unique_concrete_method:
293 case exclusive_concrete_methods_2:
294 return x.as_method(oop_recorder)->method_holder();
295 }
296 return NULL; // let NULL be NULL
297 }
298
299 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
300 assert(must_be_in_vm(), "raw oops here");
301 switch (dept) {
302 case abstract_with_exclusive_concrete_subtypes_2:
303 assert(x->is_klass(), "sanity");
304 return (Klass*) x;
305 case unique_concrete_method:
306 case exclusive_concrete_methods_2:
307 assert(x->is_method(), "sanity");
308 return ((Method*)x)->method_holder();
309 }
310 return NULL; // let NULL be NULL
311 }
312
313 void Dependencies::encode_content_bytes() {
314 sort_all_deps();
315
316 // cast is safe, no deps can overflow INT_MAX
317 CompressedWriteStream bytes((int)estimate_size_in_bytes());
318
319 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
320 DepType dept = (DepType)deptv;
321 GrowableArray<DepValue>* deps = _deps[dept];
322 if (deps->length() == 0) continue;
323 int stride = dep_args(dept);
324 int ctxkj = dep_context_arg(dept); // -1 if no context arg
325 assert(stride > 0, "sanity");
326 for (int i = 0; i < deps->length(); i += stride) {
327 jbyte code_byte = (jbyte)dept;
328 int skipj = -1;
329 if (ctxkj >= 0 && ctxkj+1 < stride) {
330 Klass* ctxk = deps->at(i+ctxkj+0).as_klass(_oop_recorder);
331 DepValue x = deps->at(i+ctxkj+1); // following argument
332 if (ctxk == ctxk_encoded_as_null(_oop_recorder, dept, x)) {
333 skipj = ctxkj; // we win: maybe one less oop to keep track of
334 code_byte |= default_context_type_bit;
335 }
336 }
337 bytes.write_byte(code_byte);
338 for (int j = 0; j < stride; j++) {
339 if (j == skipj) continue;
340 DepValue v = deps->at(i+j);
341 int idx = v.index();
342 bytes.write_int(idx);
343 }
344 }
345 }
346
347 // write a sentinel byte to mark the end
348 bytes.write_byte(end_marker);
349
350 // round it out to a word boundary
351 while (bytes.position() % sizeof(HeapWord) != 0) {
352 bytes.write_byte(end_marker);
353 }
354
355 // check whether the dept byte encoding really works
356 assert((jbyte)default_context_type_bit != 0, "byte overflow");
357
358 _content_bytes = bytes.buffer();
359 _size_in_bytes = bytes.position();
360 }
361
362
363 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
364 "end_marker",
365 "evol_method",
366 "leaf_type",
367 "abstract_with_unique_concrete_subtype",
368 "abstract_with_no_concrete_subtype",
369 "concrete_with_no_concrete_subtype",
370 "unique_concrete_method",
371 "abstract_with_exclusive_concrete_subtypes_2",
372 "exclusive_concrete_methods_2",
373 "no_finalizable_subclasses",
374 "call_site_target_value"
375 };
376
377 int Dependencies::_dep_args[TYPE_LIMIT] = {
378 -1,// end_marker
379 1, // evol_method m
380 1, // leaf_type ctxk
381 2, // abstract_with_unique_concrete_subtype ctxk, k
382 1, // abstract_with_no_concrete_subtype ctxk
383 1, // concrete_with_no_concrete_subtype ctxk
384 2, // unique_concrete_method ctxk, m
385 3, // unique_concrete_subtypes_2 ctxk, k1, k2
386 3, // unique_concrete_methods_2 ctxk, m1, m2
387 1, // no_finalizable_subclasses ctxk
388 2 // call_site_target_value call_site, method_handle
389 };
390
391 const char* Dependencies::dep_name(Dependencies::DepType dept) {
392 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
393 return _dep_name[dept];
394 }
395
396 int Dependencies::dep_args(Dependencies::DepType dept) {
397 if (!dept_in_mask(dept, all_types)) return -1;
398 return _dep_args[dept];
399 }
400
401 void Dependencies::check_valid_dependency_type(DepType dept) {
402 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
403 }
404
405 // for the sake of the compiler log, print out current dependencies:
406 void Dependencies::log_all_dependencies() {
407 if (log() == NULL) return;
408 DepValue args[max_arg_count];
409 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
410 DepType dept = (DepType)deptv;
411 GrowableArray<DepValue>* deps = _deps[dept];
412 if (deps->length() == 0) continue;
413 int stride = dep_args(dept);
414 for (int i = 0; i < deps->length(); i += stride) {
415 for (int j = 0; j < stride; j++) {
416 // flush out the identities before printing
417 args[j] = deps->at(i+j);
418 }
419 write_dependency_to(log(), dept, stride, args);
420 }
421 }
422 }
423
424 void Dependencies::write_dependency_to(CompileLog* log,
425 DepType dept,
426 int nargs, DepValue args[],
427 Klass* witness) {
428 if (log == NULL) {
429 return;
430 }
431 ciEnv* env = ciEnv::current();
432 ciBaseObject* ciargs[max_arg_count];
433 assert(nargs <= max_arg_count, "oob");
434 for (int j = 0; j < nargs; j++) {
435 if (args[j].is_object()) {
436 ciargs[j] = env->get_object(JNIHandles::resolve(args[j].as_object(_oop_recorder)));
437 } else {
438 ciargs[j] = env->get_metadata(args[j].as_metadata(_oop_recorder));
439 }
440 }
441 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
442 }
443
444 void Dependencies::write_dependency_to(CompileLog* log,
445 DepType dept,
446 int nargs, DepArgument args[],
447 Klass* witness) {
448 if (log == NULL) {
449 return;
450 }
451 ciEnv* env = ciEnv::current();
452 ciBaseObject* ciargs[max_arg_count];
453 assert(nargs <= max_arg_count, "oob");
454 for (int j = 0; j < nargs; j++) {
455 if (args[j].is_oop()) {
456 ciargs[j] = env->get_object(args[j].oop_value());
457 } else {
458 ciargs[j] = env->get_metadata(args[j].metadata_value());
459 }
460 }
461 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
462 }
463
464 void Dependencies::write_dependency_to(CompileLog* log,
465 DepType dept,
466 int nargs, ciBaseObject* args[],
467 Klass* witness) {
468 if (log == NULL) return;
469 assert(nargs <= max_arg_count, "oob");
470 int argids[max_arg_count];
471 int ctxkj = dep_context_arg(dept); // -1 if no context arg
472 int j;
473 for (j = 0; j < nargs; j++) {
474 if (args[j]->is_object()) {
475 argids[j] = log->identify(args[j]->as_object());
476 } else {
477 argids[j] = log->identify(args[j]->as_metadata());
478 }
479 }
480 if (witness != NULL) {
481 log->begin_elem("dependency_failed");
482 } else {
483 log->begin_elem("dependency");
484 }
485 log->print(" type='%s'", dep_name(dept));
486 if (ctxkj >= 0) {
487 log->print(" ctxk='%d'", argids[ctxkj]);
488 }
489 // write remaining arguments, if any.
490 for (j = 0; j < nargs; j++) {
491 if (j == ctxkj) continue; // already logged
492 if (j == 1) {
493 log->print( " x='%d'", argids[j]);
494 } else {
495 log->print(" x%d='%d'", j, argids[j]);
496 }
497 }
498 if (witness != NULL) {
499 log->object("witness", witness);
500 log->stamp();
501 }
502 log->end_elem();
503 }
504
505 void Dependencies::write_dependency_to(xmlStream* xtty,
506 DepType dept,
507 int nargs, DepArgument args[],
508 Klass* witness) {
509 if (xtty == NULL) return;
510 ttyLocker ttyl;
511 int ctxkj = dep_context_arg(dept); // -1 if no context arg
512 if (witness != NULL) {
513 xtty->begin_elem("dependency_failed");
514 } else {
515 xtty->begin_elem("dependency");
516 }
517 xtty->print(" type='%s'", dep_name(dept));
518 if (ctxkj >= 0) {
519 xtty->object("ctxk", args[ctxkj].metadata_value());
520 }
521 // write remaining arguments, if any.
522 for (int j = 0; j < nargs; j++) {
523 if (j == ctxkj) continue; // already logged
524 if (j == 1) {
525 if (args[j].is_oop()) {
526 xtty->object("x", args[j].oop_value());
527 } else {
528 xtty->object("x", args[j].metadata_value());
529 }
530 } else {
531 char xn[10]; sprintf(xn, "x%d", j);
532 if (args[j].is_oop()) {
533 xtty->object(xn, args[j].oop_value());
534 } else {
535 xtty->object(xn, args[j].metadata_value());
536 }
537 }
538 }
539 if (witness != NULL) {
540 xtty->object("witness", witness);
541 xtty->stamp();
542 }
543 xtty->end_elem();
544 }
545
546 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[],
547 Klass* witness) {
548 ResourceMark rm;
549 ttyLocker ttyl; // keep the following output all in one block
550 tty->print_cr("%s of type %s",
551 (witness == NULL)? "Dependency": "Failed dependency",
552 dep_name(dept));
553 // print arguments
554 int ctxkj = dep_context_arg(dept); // -1 if no context arg
555 for (int j = 0; j < nargs; j++) {
556 DepArgument arg = args[j];
557 bool put_star = false;
558 if (arg.is_null()) continue;
559 const char* what;
560 if (j == ctxkj) {
561 assert(arg.is_metadata(), "must be");
562 what = "context";
563 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
564 } else if (arg.is_method()) {
565 what = "method ";
566 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
567 } else if (arg.is_klass()) {
568 what = "class ";
569 } else {
570 what = "object ";
571 }
572 tty->print(" %s = %s", what, (put_star? "*": ""));
573 if (arg.is_klass())
574 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
575 else if (arg.is_method())
576 ((Method*)arg.metadata_value())->print_value();
577 else
578 ShouldNotReachHere(); // Provide impl for this type.
579 tty->cr();
580 }
581 if (witness != NULL) {
582 bool put_star = !Dependencies::is_concrete_klass(witness);
583 tty->print_cr(" witness = %s%s",
584 (put_star? "*": ""),
585 witness->external_name());
586 }
587 }
588
589 void Dependencies::DepStream::log_dependency(Klass* witness) {
590 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
591 ResourceMark rm;
592 int nargs = argument_count();
593 DepArgument args[max_arg_count];
594 for (int j = 0; j < nargs; j++) {
595 if (type() == call_site_target_value) {
596 args[j] = argument_oop(j);
597 } else {
598 args[j] = argument(j);
599 }
600 }
601 if (_deps != NULL && _deps->log() != NULL) {
602 Dependencies::write_dependency_to(_deps->log(),
603 type(), nargs, args, witness);
604 } else {
605 Dependencies::write_dependency_to(xtty,
606 type(), nargs, args, witness);
607 }
608 }
609
610 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
611 int nargs = argument_count();
612 DepArgument args[max_arg_count];
613 for (int j = 0; j < nargs; j++) {
614 args[j] = argument(j);
615 }
616 Dependencies::print_dependency(type(), nargs, args, witness);
617 if (verbose) {
618 if (_code != NULL) {
619 tty->print(" code: ");
620 _code->print_value_on(tty);
621 tty->cr();
622 }
623 }
624 }
625
626
627 /// Dependency stream support (decodes dependencies from an nmethod):
628
629 #ifdef ASSERT
630 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
631 assert(must_be_in_vm(), "raw oops here");
632 _byte_limit = byte_limit;
633 _type = (DepType)(end_marker-1); // defeat "already at end" assert
634 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
635 }
636 #endif //ASSERT
637
638 bool Dependencies::DepStream::next() {
639 assert(_type != end_marker, "already at end");
640 if (_bytes.position() == 0 && _code != NULL
641 && _code->dependencies_size() == 0) {
642 // Method has no dependencies at all.
643 return false;
644 }
645 int code_byte = (_bytes.read_byte() & 0xFF);
646 if (code_byte == end_marker) {
647 DEBUG_ONLY(_type = end_marker);
648 return false;
649 } else {
650 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
651 code_byte -= ctxk_bit;
652 DepType dept = (DepType)code_byte;
653 _type = dept;
654 Dependencies::check_valid_dependency_type(dept);
655 int stride = _dep_args[dept];
656 assert(stride == dep_args(dept), "sanity");
657 int skipj = -1;
658 if (ctxk_bit != 0) {
659 skipj = 0; // currently the only context argument is at zero
660 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
661 }
662 for (int j = 0; j < stride; j++) {
663 _xi[j] = (j == skipj)? 0: _bytes.read_int();
664 }
665 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
666 return true;
667 }
668 }
669
670 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
671 Metadata* o = NULL;
672 if (_code != NULL) {
673 o = _code->metadata_at(i);
674 } else {
675 o = _deps->oop_recorder()->metadata_at(i);
676 }
677 assert(o == NULL || o->is_metaspace_object(),
678 err_msg("Should be metadata " PTR_FORMAT, o));
679 return o;
680 }
681
682 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
683 return (_code != NULL)
684 ? _code->oop_at(i)
685 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
686 }
687
688 Metadata* Dependencies::DepStream::argument(int i) {
689 Metadata* result = recorded_metadata_at(argument_index(i));
690
691 if (result == NULL) { // Explicit context argument can be compressed
692 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
693 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
694 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
695 }
696 }
697
698 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
699 return result;
700 }
701
702 oop Dependencies::DepStream::argument_oop(int i) {
703 oop result = recorded_oop_at(argument_index(i));
704 assert(result == NULL || result->is_oop(), "must be");
705 return result;
706 }
707
708 Klass* Dependencies::DepStream::context_type() {
709 assert(must_be_in_vm(), "raw oops here");
710
711 // Most dependencies have an explicit context type argument.
712 {
713 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
714 if (ctxkj >= 0) {
715 Metadata* k = argument(ctxkj);
716 assert(k != NULL && k->is_klass(), "type check");
717 return (Klass*)k;
718 }
719 }
720
721 // Some dependencies are using the klass of the first object
722 // argument as implicit context type (e.g. call_site_target_value).
723 {
724 int ctxkj = dep_implicit_context_arg(type());
725 if (ctxkj >= 0) {
726 Klass* k = argument_oop(ctxkj)->klass();
727 assert(k != NULL && k->is_klass(), "type check");
728 return (Klass*) k;
729 }
730 }
731
732 // And some dependencies don't have a context type at all,
733 // e.g. evol_method.
734 return NULL;
735 }
736
737 /// Checking dependencies:
738
739 // This hierarchy walker inspects subtypes of a given type,
740 // trying to find a "bad" class which breaks a dependency.
741 // Such a class is called a "witness" to the broken dependency.
742 // While searching around, we ignore "participants", which
743 // are already known to the dependency.
744 class ClassHierarchyWalker {
745 public:
746 enum { PARTICIPANT_LIMIT = 3 };
747
748 private:
749 // optional method descriptor to check for:
750 Symbol* _name;
751 Symbol* _signature;
752
753 // special classes which are not allowed to be witnesses:
754 Klass* _participants[PARTICIPANT_LIMIT+1];
755 int _num_participants;
756
757 // cache of method lookups
758 Method* _found_methods[PARTICIPANT_LIMIT+1];
759
760 // if non-zero, tells how many witnesses to convert to participants
761 int _record_witnesses;
762
763 void initialize(Klass* participant) {
764 _record_witnesses = 0;
765 _participants[0] = participant;
766 _found_methods[0] = NULL;
767 _num_participants = 0;
768 if (participant != NULL) {
769 // Terminating NULL.
770 _participants[1] = NULL;
771 _found_methods[1] = NULL;
772 _num_participants = 1;
773 }
774 }
775
776 void initialize_from_method(Method* m) {
777 assert(m != NULL && m->is_method(), "sanity");
778 _name = m->name();
779 _signature = m->signature();
780 }
781
782 public:
783 // The walker is initialized to recognize certain methods and/or types
784 // as friendly participants.
785 ClassHierarchyWalker(Klass* participant, Method* m) {
786 initialize_from_method(m);
787 initialize(participant);
788 }
789 ClassHierarchyWalker(Method* m) {
790 initialize_from_method(m);
791 initialize(NULL);
792 }
793 ClassHierarchyWalker(Klass* participant = NULL) {
794 _name = NULL;
795 _signature = NULL;
796 initialize(participant);
797 }
798
799 // This is common code for two searches: One for concrete subtypes,
800 // the other for concrete method implementations and overrides.
801 bool doing_subtype_search() {
802 return _name == NULL;
803 }
804
805 int num_participants() { return _num_participants; }
806 Klass* participant(int n) {
807 assert((uint)n <= (uint)_num_participants, "oob");
808 return _participants[n];
809 }
810
811 // Note: If n==num_participants, returns NULL.
812 Method* found_method(int n) {
813 assert((uint)n <= (uint)_num_participants, "oob");
814 Method* fm = _found_methods[n];
815 assert(n == _num_participants || fm != NULL, "proper usage");
816 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
817 return fm;
818 }
819
820 #ifdef ASSERT
821 // Assert that m is inherited into ctxk, without intervening overrides.
822 // (May return true even if this is not true, in corner cases where we punt.)
823 bool check_method_context(Klass* ctxk, Method* m) {
824 if (m->method_holder() == ctxk)
825 return true; // Quick win.
826 if (m->is_private())
827 return false; // Quick lose. Should not happen.
828 if (!(m->is_public() || m->is_protected()))
829 // The override story is complex when packages get involved.
830 return true; // Must punt the assertion to true.
831 Klass* k = ctxk;
832 Method* lm = k->lookup_method(m->name(), m->signature());
833 if (lm == NULL && k->oop_is_instance()) {
834 // It might be an interface method
835 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
836 m->signature());
837 }
838 if (lm == m)
839 // Method m is inherited into ctxk.
840 return true;
841 if (lm != NULL) {
842 if (!(lm->is_public() || lm->is_protected())) {
843 // Method is [package-]private, so the override story is complex.
844 return true; // Must punt the assertion to true.
845 }
846 if (lm->is_static()) {
847 // Static methods don't override non-static so punt
848 return true;
849 }
850 if ( !Dependencies::is_concrete_method(lm)
851 && !Dependencies::is_concrete_method(m)
852 && lm->method_holder()->is_subtype_of(m->method_holder()))
853 // Method m is overridden by lm, but both are non-concrete.
854 return true;
855 }
856 ResourceMark rm;
857 tty->print_cr("Dependency method not found in the associated context:");
858 tty->print_cr(" context = %s", ctxk->external_name());
859 tty->print( " method = "); m->print_short_name(tty); tty->cr();
860 if (lm != NULL) {
861 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
862 }
863 return false;
864 }
865 #endif
866
867 void add_participant(Klass* participant) {
868 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
869 int np = _num_participants++;
870 _participants[np] = participant;
871 _participants[np+1] = NULL;
872 _found_methods[np+1] = NULL;
873 }
874
875 void record_witnesses(int add) {
876 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
877 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
878 _record_witnesses = add;
879 }
880
881 bool is_witness(Klass* k) {
882 if (doing_subtype_search()) {
883 return Dependencies::is_concrete_klass(k);
884 } else {
885 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
886 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
887 _found_methods[_num_participants] = m;
888 // Note: If add_participant(k) is called,
889 // the method m will already be memoized for it.
890 return true;
891 }
892 }
893
894 bool is_participant(Klass* k) {
895 if (k == _participants[0]) {
896 return true;
897 } else if (_num_participants <= 1) {
898 return false;
899 } else {
900 return in_list(k, &_participants[1]);
901 }
902 }
903 bool ignore_witness(Klass* witness) {
904 if (_record_witnesses == 0) {
905 return false;
906 } else {
907 --_record_witnesses;
908 add_participant(witness);
909 return true;
910 }
911 }
912 static bool in_list(Klass* x, Klass** list) {
913 for (int i = 0; ; i++) {
914 Klass* y = list[i];
915 if (y == NULL) break;
916 if (y == x) return true;
917 }
918 return false; // not in list
919 }
920
921 private:
922 // the actual search method:
923 Klass* find_witness_anywhere(Klass* context_type,
924 bool participants_hide_witnesses,
925 bool top_level_call = true);
926 // the spot-checking version:
927 Klass* find_witness_in(KlassDepChange& changes,
928 Klass* context_type,
929 bool participants_hide_witnesses);
930 public:
931 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
932 assert(doing_subtype_search(), "must set up a subtype search");
933 // When looking for unexpected concrete types,
934 // do not look beneath expected ones.
935 const bool participants_hide_witnesses = true;
936 // CX > CC > C' is OK, even if C' is new.
937 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
938 if (changes != NULL) {
939 return find_witness_in(*changes, context_type, participants_hide_witnesses);
940 } else {
941 return find_witness_anywhere(context_type, participants_hide_witnesses);
942 }
943 }
944 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
945 assert(!doing_subtype_search(), "must set up a method definer search");
946 // When looking for unexpected concrete methods,
947 // look beneath expected ones, to see if there are overrides.
948 const bool participants_hide_witnesses = true;
949 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
950 if (changes != NULL) {
951 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
952 } else {
953 return find_witness_anywhere(context_type, !participants_hide_witnesses);
954 }
955 }
956 };
957
958 #ifndef PRODUCT
959 static int deps_find_witness_calls = 0;
960 static int deps_find_witness_steps = 0;
961 static int deps_find_witness_recursions = 0;
962 static int deps_find_witness_singles = 0;
963 static int deps_find_witness_print = 0; // set to -1 to force a final print
964 static bool count_find_witness_calls() {
965 if (TraceDependencies || LogCompilation) {
966 int pcount = deps_find_witness_print + 1;
967 bool final_stats = (pcount == 0);
968 bool initial_call = (pcount == 1);
969 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
970 if (pcount < 0) pcount = 1; // crude overflow protection
971 deps_find_witness_print = pcount;
972 if (VerifyDependencies && initial_call) {
973 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
974 }
975 if (occasional_print || final_stats) {
976 // Every now and then dump a little info about dependency searching.
977 if (xtty != NULL) {
978 ttyLocker ttyl;
979 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
980 deps_find_witness_calls,
981 deps_find_witness_steps,
982 deps_find_witness_recursions,
983 deps_find_witness_singles);
984 }
985 if (final_stats || (TraceDependencies && WizardMode)) {
986 ttyLocker ttyl;
987 tty->print_cr("Dependency check (find_witness) "
988 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
989 deps_find_witness_calls,
990 deps_find_witness_steps,
991 (double)deps_find_witness_steps / deps_find_witness_calls,
992 deps_find_witness_recursions,
993 deps_find_witness_singles);
994 }
995 }
996 return true;
997 }
998 return false;
999 }
1000 #else
1001 #define count_find_witness_calls() (0)
1002 #endif //PRODUCT
1003
1004
1005 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1006 Klass* context_type,
1007 bool participants_hide_witnesses) {
1008 assert(changes.involves_context(context_type), "irrelevant dependency");
1009 Klass* new_type = changes.new_type();
1010
1011 (void)count_find_witness_calls();
1012 NOT_PRODUCT(deps_find_witness_singles++);
1013
1014 // Current thread must be in VM (not native mode, as in CI):
1015 assert(must_be_in_vm(), "raw oops here");
1016 // Must not move the class hierarchy during this check:
1017 assert_locked_or_safepoint(Compile_lock);
1018
1019 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1020 if (nof_impls > 1) {
1021 // Avoid this case: *I.m > { A.m, C }; B.m > C
1022 // %%% Until this is fixed more systematically, bail out.
1023 // See corresponding comment in find_witness_anywhere.
1024 return context_type;
1025 }
1026
1027 assert(!is_participant(new_type), "only old classes are participants");
1028 if (participants_hide_witnesses) {
1029 // If the new type is a subtype of a participant, we are done.
1030 for (int i = 0; i < num_participants(); i++) {
1031 Klass* part = participant(i);
1032 if (part == NULL) continue;
1033 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1034 "correct marking of participants, b/c new_type is unique");
1035 if (changes.involves_context(part)) {
1036 // new guy is protected from this check by previous participant
1037 return NULL;
1038 }
1039 }
1040 }
1041
1042 if (is_witness(new_type) &&
1043 !ignore_witness(new_type)) {
1044 return new_type;
1045 }
1046
1047 return NULL;
1048 }
1049
1050
1051 // Walk hierarchy under a context type, looking for unexpected types.
1052 // Do not report participant types, and recursively walk beneath
1053 // them only if participants_hide_witnesses is false.
1054 // If top_level_call is false, skip testing the context type,
1055 // because the caller has already considered it.
1056 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1057 bool participants_hide_witnesses,
1058 bool top_level_call) {
1059 // Current thread must be in VM (not native mode, as in CI):
1060 assert(must_be_in_vm(), "raw oops here");
1061 // Must not move the class hierarchy during this check:
1062 assert_locked_or_safepoint(Compile_lock);
1063
1064 bool do_counts = count_find_witness_calls();
1065
1066 // Check the root of the sub-hierarchy first.
1067 if (top_level_call) {
1068 if (do_counts) {
1069 NOT_PRODUCT(deps_find_witness_calls++);
1070 NOT_PRODUCT(deps_find_witness_steps++);
1071 }
1072 if (is_participant(context_type)) {
1073 if (participants_hide_witnesses) return NULL;
1074 // else fall through to search loop...
1075 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1076 // The context is an abstract class or interface, to start with.
1077 return context_type;
1078 }
1079 }
1080
1081 // Now we must check each implementor and each subclass.
1082 // Use a short worklist to avoid blowing the stack.
1083 // Each worklist entry is a *chain* of subklass siblings to process.
1084 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1085 Klass* chains[CHAINMAX];
1086 int chaini = 0; // index into worklist
1087 Klass* chain; // scratch variable
1088 #define ADD_SUBCLASS_CHAIN(k) { \
1089 assert(chaini < CHAINMAX, "oob"); \
1090 chain = InstanceKlass::cast(k)->subklass(); \
1091 if (chain != NULL) chains[chaini++] = chain; }
1092
1093 // Look for non-abstract subclasses.
1094 // (Note: Interfaces do not have subclasses.)
1095 ADD_SUBCLASS_CHAIN(context_type);
1096
1097 // If it is an interface, search its direct implementors.
1098 // (Their subclasses are additional indirect implementors.
1099 // See InstanceKlass::add_implementor.)
1100 // (Note: nof_implementors is always zero for non-interfaces.)
1101 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1102 if (nof_impls > 1) {
1103 // Avoid this case: *I.m > { A.m, C }; B.m > C
1104 // Here, I.m has 2 concrete implementations, but m appears unique
1105 // as A.m, because the search misses B.m when checking C.
1106 // The inherited method B.m was getting missed by the walker
1107 // when interface 'I' was the starting point.
1108 // %%% Until this is fixed more systematically, bail out.
1109 // (Old CHA had the same limitation.)
1110 return context_type;
1111 }
1112 if (nof_impls > 0) {
1113 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1114 assert(impl != NULL, "just checking");
1115 // If impl is the same as the context_type, then more than one
1116 // implementor has seen. No exact info in this case.
1117 if (impl == context_type) {
1118 return context_type; // report an inexact witness to this sad affair
1119 }
1120 if (do_counts)
1121 { NOT_PRODUCT(deps_find_witness_steps++); }
1122 if (is_participant(impl)) {
1123 if (!participants_hide_witnesses) {
1124 ADD_SUBCLASS_CHAIN(impl);
1125 }
1126 } else if (is_witness(impl) && !ignore_witness(impl)) {
1127 return impl;
1128 } else {
1129 ADD_SUBCLASS_CHAIN(impl);
1130 }
1131 }
1132
1133 // Recursively process each non-trivial sibling chain.
1134 while (chaini > 0) {
1135 Klass* chain = chains[--chaini];
1136 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1137 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1138 if (is_participant(sub)) {
1139 if (participants_hide_witnesses) continue;
1140 // else fall through to process this guy's subclasses
1141 } else if (is_witness(sub) && !ignore_witness(sub)) {
1142 return sub;
1143 }
1144 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1145 // Fast path. (Partially disabled if VerifyDependencies.)
1146 ADD_SUBCLASS_CHAIN(sub);
1147 } else {
1148 // Worklist overflow. Do a recursive call. Should be rare.
1149 // The recursive call will have its own worklist, of course.
1150 // (Note that sub has already been tested, so that there is
1151 // no need for the recursive call to re-test. That's handy,
1152 // since the recursive call sees sub as the context_type.)
1153 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1154 Klass* witness = find_witness_anywhere(sub,
1155 participants_hide_witnesses,
1156 /*top_level_call=*/ false);
1157 if (witness != NULL) return witness;
1158 }
1159 }
1160 }
1161
1162 // No witness found. The dependency remains unbroken.
1163 return NULL;
1164 #undef ADD_SUBCLASS_CHAIN
1165 }
1166
1167
1168 bool Dependencies::is_concrete_klass(Klass* k) {
1169 if (k->is_abstract()) return false;
1170 // %%% We could treat classes which are concrete but
1171 // have not yet been instantiated as virtually abstract.
1172 // This would require a deoptimization barrier on first instantiation.
1173 //if (k->is_not_instantiated()) return false;
1174 return true;
1175 }
1176
1177 bool Dependencies::is_concrete_method(Method* m) {
1178 // Statics are irrelevant to virtual call sites.
1179 if (m->is_static()) return false;
1180
1181 // We could also return false if m does not yet appear to be
1182 // executed, if the VM version supports this distinction also.
1183 return !m->is_abstract() &&
1184 !InstanceKlass::cast(m->method_holder())->is_interface();
1185 // TODO: investigate whether default methods should be
1186 // considered as "concrete" in this situation. For now they
1187 // are not.
1188 }
1189
1190
1191 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1192 if (k->is_interface()) return NULL;
1193 if (k->has_finalizer()) return k;
1194 k = k->subklass();
1195 while (k != NULL) {
1196 Klass* result = find_finalizable_subclass(k);
1197 if (result != NULL) return result;
1198 k = k->next_sibling();
1199 }
1200 return NULL;
1201 }
1202
1203
1204 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1205 if (k->is_abstract()) return false;
1206 // We could also return false if k does not yet appear to be
1207 // instantiated, if the VM version supports this distinction also.
1208 //if (k->is_not_instantiated()) return false;
1209 return true;
1210 }
1211
1212 bool Dependencies::is_concrete_method(ciMethod* m) {
1213 // Statics are irrelevant to virtual call sites.
1214 if (m->is_static()) return false;
1215
1216 // We could also return false if m does not yet appear to be
1217 // executed, if the VM version supports this distinction also.
1218 return !m->is_abstract();
1219 }
1220
1221
1222 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1223 return k->has_finalizable_subclass();
1224 }
1225
1226
1227 // Any use of the contents (bytecodes) of a method must be
1228 // marked by an "evol_method" dependency, if those contents
1229 // can change. (Note: A method is always dependent on itself.)
1230 Klass* Dependencies::check_evol_method(Method* m) {
1231 assert(must_be_in_vm(), "raw oops here");
1232 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1233 // Or is there a now a breakpoint?
1234 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1235 if (m->is_old()
1236 || m->number_of_breakpoints() > 0) {
1237 return m->method_holder();
1238 } else {
1239 return NULL;
1240 }
1241 }
1242
1243 // This is a strong assertion: It is that the given type
1244 // has no subtypes whatever. It is most useful for
1245 // optimizing checks on reflected types or on array types.
1246 // (Checks on types which are derived from real instances
1247 // can be optimized more strongly than this, because we
1248 // know that the checked type comes from a concrete type,
1249 // and therefore we can disregard abstract types.)
1250 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1251 assert(must_be_in_vm(), "raw oops here");
1252 assert_locked_or_safepoint(Compile_lock);
1253 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1254 Klass* sub = ctx->subklass();
1255 if (sub != NULL) {
1256 return sub;
1257 } else if (ctx->nof_implementors() != 0) {
1258 // if it is an interface, it must be unimplemented
1259 // (if it is not an interface, nof_implementors is always zero)
1260 Klass* impl = ctx->implementor();
1261 assert(impl != NULL, "must be set");
1262 return impl;
1263 } else {
1264 return NULL;
1265 }
1266 }
1267
1268 // Test the assertion that conck is the only concrete subtype* of ctxk.
1269 // The type conck itself is allowed to have have further concrete subtypes.
1270 // This allows the compiler to narrow occurrences of ctxk by conck,
1271 // when dealing with the types of actual instances.
1272 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1273 Klass* conck,
1274 KlassDepChange* changes) {
1275 ClassHierarchyWalker wf(conck);
1276 return wf.find_witness_subtype(ctxk, changes);
1277 }
1278
1279 // If a non-concrete class has no concrete subtypes, it is not (yet)
1280 // instantiatable. This can allow the compiler to make some paths go
1281 // dead, if they are gated by a test of the type.
1282 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1283 KlassDepChange* changes) {
1284 // Find any concrete subtype, with no participants:
1285 ClassHierarchyWalker wf;
1286 return wf.find_witness_subtype(ctxk, changes);
1287 }
1288
1289
1290 // If a concrete class has no concrete subtypes, it can always be
1291 // exactly typed. This allows the use of a cheaper type test.
1292 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1293 KlassDepChange* changes) {
1294 // Find any concrete subtype, with only the ctxk as participant:
1295 ClassHierarchyWalker wf(ctxk);
1296 return wf.find_witness_subtype(ctxk, changes);
1297 }
1298
1299
1300 // Find the unique concrete proper subtype of ctxk, or NULL if there
1301 // is more than one concrete proper subtype. If there are no concrete
1302 // proper subtypes, return ctxk itself, whether it is concrete or not.
1303 // The returned subtype is allowed to have have further concrete subtypes.
1304 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1305 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1306 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1307 wf.record_witnesses(1); // Record one other witness when walking.
1308 Klass* wit = wf.find_witness_subtype(ctxk);
1309 if (wit != NULL) return NULL; // Too many witnesses.
1310 Klass* conck = wf.participant(0);
1311 if (conck == NULL) {
1312 #ifndef PRODUCT
1313 // Make sure the dependency mechanism will pass this discovery:
1314 if (VerifyDependencies) {
1315 // Turn off dependency tracing while actually testing deps.
1316 FlagSetting fs(TraceDependencies, false);
1317 if (!Dependencies::is_concrete_klass(ctxk)) {
1318 guarantee(NULL ==
1319 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1320 "verify dep.");
1321 } else {
1322 guarantee(NULL ==
1323 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1324 "verify dep.");
1325 }
1326 }
1327 #endif //PRODUCT
1328 return ctxk; // Return ctxk as a flag for "no subtypes".
1329 } else {
1330 #ifndef PRODUCT
1331 // Make sure the dependency mechanism will pass this discovery:
1332 if (VerifyDependencies) {
1333 // Turn off dependency tracing while actually testing deps.
1334 FlagSetting fs(TraceDependencies, false);
1335 if (!Dependencies::is_concrete_klass(ctxk)) {
1336 guarantee(NULL == (void *)
1337 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1338 "verify dep.");
1339 }
1340 }
1341 #endif //PRODUCT
1342 return conck;
1343 }
1344 }
1345
1346 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1347 // except possibly for further subtypes of k[12] themselves.
1348 // The context type must be abstract. The types k1 and k2 are themselves
1349 // allowed to have further concrete subtypes.
1350 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1351 Klass* ctxk,
1352 Klass* k1,
1353 Klass* k2,
1354 KlassDepChange* changes) {
1355 ClassHierarchyWalker wf;
1356 wf.add_participant(k1);
1357 wf.add_participant(k2);
1358 return wf.find_witness_subtype(ctxk, changes);
1359 }
1360
1361 // Search ctxk for concrete implementations. If there are klen or fewer,
1362 // pack them into the given array and return the number.
1363 // Otherwise, return -1, meaning the given array would overflow.
1364 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1365 // In this search, if ctxk is concrete, it will be reported alone.
1366 // For any type CC reported, no proper subtypes of CC will be reported.
1367 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1368 int klen,
1369 Klass* karray[]) {
1370 ClassHierarchyWalker wf;
1371 wf.record_witnesses(klen);
1372 Klass* wit = wf.find_witness_subtype(ctxk);
1373 if (wit != NULL) return -1; // Too many witnesses.
1374 int num = wf.num_participants();
1375 assert(num <= klen, "oob");
1376 // Pack the result array with the good news.
1377 for (int i = 0; i < num; i++)
1378 karray[i] = wf.participant(i);
1379 #ifndef PRODUCT
1380 // Make sure the dependency mechanism will pass this discovery:
1381 if (VerifyDependencies) {
1382 // Turn off dependency tracing while actually testing deps.
1383 FlagSetting fs(TraceDependencies, false);
1384 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1385 case -1: // ctxk was itself concrete
1386 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1387 break;
1388 case 0:
1389 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1390 "verify dep.");
1391 break;
1392 case 1:
1393 guarantee(NULL == (void *)
1394 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1395 "verify dep.");
1396 break;
1397 case 2:
1398 guarantee(NULL == (void *)
1399 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1400 karray[0],
1401 karray[1]),
1402 "verify dep.");
1403 break;
1404 default:
1405 ShouldNotReachHere(); // klen > 2 yet supported
1406 }
1407 }
1408 #endif //PRODUCT
1409 return num;
1410 }
1411
1412 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1413 // Otherwise, return a class that contains an interfering method.
1414 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1415 KlassDepChange* changes) {
1416 // Here is a missing optimization: If uniqm->is_final(),
1417 // we don't really need to search beneath it for overrides.
1418 // This is probably not important, since we don't use dependencies
1419 // to track final methods. (They can't be "definalized".)
1420 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1421 return wf.find_witness_definer(ctxk, changes);
1422 }
1423
1424 // Find the set of all non-abstract methods under ctxk that match m.
1425 // (The method m must be defined or inherited in ctxk.)
1426 // Include m itself in the set, unless it is abstract.
1427 // If this set has exactly one element, return that element.
1428 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1429 ClassHierarchyWalker wf(m);
1430 assert(wf.check_method_context(ctxk, m), "proper context");
1431 wf.record_witnesses(1);
1432 Klass* wit = wf.find_witness_definer(ctxk);
1433 if (wit != NULL) return NULL; // Too many witnesses.
1434 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1435 if (Dependencies::is_concrete_method(m)) {
1436 if (fm == NULL) {
1437 // It turns out that m was always the only implementation.
1438 fm = m;
1439 } else if (fm != m) {
1440 // Two conflicting implementations after all.
1441 // (This can happen if m is inherited into ctxk and fm overrides it.)
1442 return NULL;
1443 }
1444 }
1445 #ifndef PRODUCT
1446 // Make sure the dependency mechanism will pass this discovery:
1447 if (VerifyDependencies && fm != NULL) {
1448 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1449 "verify dep.");
1450 }
1451 #endif //PRODUCT
1452 return fm;
1453 }
1454
1455 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1456 Method* m1,
1457 Method* m2,
1458 KlassDepChange* changes) {
1459 ClassHierarchyWalker wf(m1);
1460 wf.add_participant(m1->method_holder());
1461 wf.add_participant(m2->method_holder());
1462 return wf.find_witness_definer(ctxk, changes);
1463 }
1464
1465 // Find the set of all non-abstract methods under ctxk that match m[0].
1466 // (The method m[0] must be defined or inherited in ctxk.)
1467 // Include m itself in the set, unless it is abstract.
1468 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1469 // (The length may be zero if no concrete methods are found anywhere.)
1470 // If there are too many concrete methods to fit in marray, return -1.
1471 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1472 int mlen,
1473 Method* marray[]) {
1474 Method* m0 = marray[0];
1475 ClassHierarchyWalker wf(m0);
1476 assert(wf.check_method_context(ctxk, m0), "proper context");
1477 wf.record_witnesses(mlen);
1478 bool participants_hide_witnesses = true;
1479 Klass* wit = wf.find_witness_definer(ctxk);
1480 if (wit != NULL) return -1; // Too many witnesses.
1481 int num = wf.num_participants();
1482 assert(num <= mlen, "oob");
1483 // Keep track of whether m is also part of the result set.
1484 int mfill = 0;
1485 assert(marray[mfill] == m0, "sanity");
1486 if (Dependencies::is_concrete_method(m0))
1487 mfill++; // keep m0 as marray[0], the first result
1488 for (int i = 0; i < num; i++) {
1489 Method* fm = wf.found_method(i);
1490 if (fm == m0) continue; // Already put this guy in the list.
1491 if (mfill == mlen) {
1492 return -1; // Oops. Too many methods after all!
1493 }
1494 marray[mfill++] = fm;
1495 }
1496 #ifndef PRODUCT
1497 // Make sure the dependency mechanism will pass this discovery:
1498 if (VerifyDependencies) {
1499 // Turn off dependency tracing while actually testing deps.
1500 FlagSetting fs(TraceDependencies, false);
1501 switch (mfill) {
1502 case 1:
1503 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1504 "verify dep.");
1505 break;
1506 case 2:
1507 guarantee(NULL == (void *)
1508 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1509 "verify dep.");
1510 break;
1511 default:
1512 ShouldNotReachHere(); // mlen > 2 yet supported
1513 }
1514 }
1515 #endif //PRODUCT
1516 return mfill;
1517 }
1518
1519
1520 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1521 Klass* search_at = ctxk;
1522 if (changes != NULL)
1523 search_at = changes->new_type(); // just look at the new bit
1524 return find_finalizable_subclass(search_at);
1525 }
1526
1527
1528 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1529 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1530 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1531 if (changes == NULL) {
1532 // Validate all CallSites
1533 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1534 return call_site->klass(); // assertion failed
1535 } else {
1536 // Validate the given CallSite
1537 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1538 assert(method_handle != changes->method_handle(), "must be");
1539 return call_site->klass(); // assertion failed
1540 }
1541 }
1542 return NULL; // assertion still valid
1543 }
1544
1545
1546 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1547 if (witness != NULL) {
1548 if (TraceDependencies) {
1549 print_dependency(witness, /*verbose=*/ true);
1550 }
1551 // The following is a no-op unless logging is enabled:
1552 log_dependency(witness);
1553 }
1554 }
1555
1556
1557 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1558 assert_locked_or_safepoint(Compile_lock);
1559 Dependencies::check_valid_dependency_type(type());
1560
1561 Klass* witness = NULL;
1562 switch (type()) {
1563 case evol_method:
1564 witness = check_evol_method(method_argument(0));
1565 break;
1566 case leaf_type:
1567 witness = check_leaf_type(context_type());
1568 break;
1569 case abstract_with_unique_concrete_subtype:
1570 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1571 break;
1572 case abstract_with_no_concrete_subtype:
1573 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1574 break;
1575 case concrete_with_no_concrete_subtype:
1576 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1577 break;
1578 case unique_concrete_method:
1579 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1580 break;
1581 case abstract_with_exclusive_concrete_subtypes_2:
1582 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1583 break;
1584 case exclusive_concrete_methods_2:
1585 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1586 break;
1587 case no_finalizable_subclasses:
1588 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1589 break;
1590 default:
1591 witness = NULL;
1592 break;
1593 }
1594 trace_and_log_witness(witness);
1595 return witness;
1596 }
1597
1598
1599 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1600 assert_locked_or_safepoint(Compile_lock);
1601 Dependencies::check_valid_dependency_type(type());
1602
1603 Klass* witness = NULL;
1604 switch (type()) {
1605 case call_site_target_value:
1606 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1607 break;
1608 default:
1609 witness = NULL;
1610 break;
1611 }
1612 trace_and_log_witness(witness);
1613 return witness;
1614 }
1615
1616
1617 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1618 // Handle klass dependency
1619 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1620 return check_klass_dependency(changes.as_klass_change());
1621
1622 // Handle CallSite dependency
1623 if (changes.is_call_site_change())
1624 return check_call_site_dependency(changes.as_call_site_change());
1625
1626 // irrelevant dependency; skip it
1627 return NULL;
1628 }
1629
1630
1631 void DepChange::print() {
1632 int nsup = 0, nint = 0;
1633 for (ContextStream str(*this); str.next(); ) {
1634 Klass* k = str.klass();
1635 switch (str.change_type()) {
1636 case Change_new_type:
1637 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1638 break;
1639 case Change_new_sub:
1640 if (!WizardMode) {
1641 ++nsup;
1642 } else {
1643 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1644 }
1645 break;
1646 case Change_new_impl:
1647 if (!WizardMode) {
1648 ++nint;
1649 } else {
1650 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1651 }
1652 break;
1653 }
1654 }
1655 if (nsup + nint != 0) {
1656 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1657 }
1658 }
1659
1660 void DepChange::ContextStream::start() {
1661 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1662 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1663 _klass = new_type;
1664 _ti_base = NULL;
1665 _ti_index = 0;
1666 _ti_limit = 0;
1667 }
1668
1669 bool DepChange::ContextStream::next() {
1670 switch (_change_type) {
1671 case Start_Klass: // initial state; _klass is the new type
1672 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1673 _ti_index = 0;
1674 _change_type = Change_new_type;
1675 return true;
1676 case Change_new_type:
1677 // fall through:
1678 _change_type = Change_new_sub;
1679 case Change_new_sub:
1680 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1681 {
1682 _klass = InstanceKlass::cast(_klass)->super();
1683 if (_klass != NULL) {
1684 return true;
1685 }
1686 }
1687 // else set up _ti_limit and fall through:
1688 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1689 _change_type = Change_new_impl;
1690 case Change_new_impl:
1691 if (_ti_index < _ti_limit) {
1692 _klass = _ti_base->at(_ti_index++);
1693 return true;
1694 }
1695 // fall through:
1696 _change_type = NO_CHANGE; // iterator is exhausted
1697 case NO_CHANGE:
1698 break;
1699 default:
1700 ShouldNotReachHere();
1701 }
1702 return false;
1703 }
1704
1705 void KlassDepChange::initialize() {
1706 // entire transaction must be under this lock:
1707 assert_lock_strong(Compile_lock);
1708
1709 // Mark all dependee and all its superclasses
1710 // Mark transitive interfaces
1711 for (ContextStream str(*this); str.next(); ) {
1712 Klass* d = str.klass();
1713 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1714 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1715 }
1716 }
1717
1718 KlassDepChange::~KlassDepChange() {
1719 // Unmark all dependee and all its superclasses
1720 // Unmark transitive interfaces
1721 for (ContextStream str(*this); str.next(); ) {
1722 Klass* d = str.klass();
1723 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1724 }
1725 }
1726
1727 bool KlassDepChange::involves_context(Klass* k) {
1728 if (k == NULL || !k->oop_is_instance()) {
1729 return false;
1730 }
1731 InstanceKlass* ik = InstanceKlass::cast(k);
1732 bool is_contained = ik->is_marked_dependent();
1733 assert(is_contained == new_type()->is_subtype_of(k),
1734 "correct marking of potential context types");
1735 return is_contained;
1736 }
1737
1738 #ifndef PRODUCT
1739 void Dependencies::print_statistics() {
1740 if (deps_find_witness_print != 0) {
1741 // Call one final time, to flush out the data.
1742 deps_find_witness_print = -1;
1743 count_find_witness_calls();
1744 }
1745 }
1746 #endif