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 "ci/ciUtilities.hpp"
31 #include "code/dependencies.hpp"
32 #include "compiler/compileLog.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "oops/objArrayKlass.hpp"
35 #include "runtime/handles.hpp"
36 #include "runtime/handles.inline.hpp"
37 #include "utilities/copy.hpp"
38
39
40 #ifdef ASSERT
41 static bool must_be_in_vm() {
42 Thread* thread = Thread::current();
43 if (thread->is_Java_thread())
44 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
45 else
46 return true; //something like this: thread->is_VM_thread();
47 }
48 #endif //ASSERT
49
50 void Dependencies::initialize(ciEnv* env) {
51 Arena* arena = env->arena();
52 _oop_recorder = env->oop_recorder();
53 _log = env->log();
54 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
55 DEBUG_ONLY(_deps[end_marker] = NULL);
56 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
57 _deps[i] = new(arena) GrowableArray<DepValue>(arena, 10, 0, DepValue());
58 }
59 _content_bytes = NULL;
60 _size_in_bytes = (size_t)-1;
61
62 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
63 }
64
65 void Dependencies::assert_evol_method(Method* m) {
66 assert_common_1(evol_method, DepValue(_oop_recorder, m));
67 }
68
69 void Dependencies::assert_leaf_type(Klass* ctxk) {
70 if (ctxk->oop_is_array()) {
71 // As a special case, support this assertion on an array type,
72 // which reduces to an assertion on its element type.
73 // Note that this cannot be done with assertions that
74 // relate to concreteness or abstractness.
75 BasicType elemt = ArrayKlass::cast(ctxk)->element_type();
76 if (is_java_primitive(elemt)) return; // Ex: int[][]
77 ctxk = ObjArrayKlass::cast(ctxk)->bottom_klass();
78 //if (ctxk->is_final()) return; // Ex: String[][]
79 }
80 check_ctxk(ctxk);
81 assert_common_1(leaf_type, DepValue(_oop_recorder, ctxk));
82 }
83
84 void Dependencies::assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck) {
85 check_ctxk_abstract(ctxk);
86 DepValue ctxk_dv(_oop_recorder, ctxk);
87 assert_common_2(abstract_with_unique_concrete_subtype, ctxk_dv, DepValue(_oop_recorder, conck, &ctxk_dv));
88 }
89
90 void Dependencies::assert_abstract_with_no_concrete_subtype(Klass* ctxk) {
91 check_ctxk_abstract(ctxk);
92 assert_common_1(abstract_with_no_concrete_subtype, DepValue(_oop_recorder, ctxk));
93 }
94
95 void Dependencies::assert_concrete_with_no_concrete_subtype(Klass* ctxk) {
96 check_ctxk_concrete(ctxk);
97 assert_common_1(concrete_with_no_concrete_subtype, DepValue(_oop_recorder, ctxk));
98 }
99
100 void Dependencies::assert_unique_concrete_method(Klass* ctxk, Method* uniqm) {
101 check_ctxk(ctxk);
102 assert_common_2(unique_concrete_method, DepValue(_oop_recorder, ctxk), DepValue(_oop_recorder, uniqm));
103 }
104
105 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(Klass* ctxk, Klass* k1, Klass* k2) {
106 check_ctxk(ctxk);
107 DepValue k1_dv(_oop_recorder, k1);
108 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1_dv, DepValue(_oop_recorder, k2, &k1_dv));
109 }
110
111 void Dependencies::assert_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2) {
112 check_ctxk(ctxk);
113 DepValue m1_dv(_oop_recorder, m1);
114 assert_common_3(exclusive_concrete_methods_2, ctxk, m1_dv, DepValue(_oop_recorder, m2, &m1_dv));
115 }
116
117 void Dependencies::assert_has_no_finalizable_subclasses(Klass* ctxk) {
118 check_ctxk(ctxk);
119 assert_common_1(no_finalizable_subclasses, DepValue(_oop_recorder, ctxk));
120 }
121
122 void Dependencies::assert_call_site_target_value(jobject call_site, jobject method_handle) {
123 ASSERT_IN_VM; // No GC can occur between resolving call_site and getting its klass
124 Klass* ctxk = JNIHandles::resolve(call_site)->klass();
125 check_ctxk(ctxk);
126 assert_common_2(call_site_target_value, DepValue(_oop_recorder, call_site), DepValue(_oop_recorder, method_handle));
127 }
128
129 // Helper function. If we are adding a new dep. under ctxk2,
130 // try to find an old dep. under a broader* ctxk1. If there is
131 //
132 bool Dependencies::maybe_merge_ctxk(GrowableArray<DepValue>* deps,
133 int ctxk_i, Klass* ctxk2) {
134 Klass* ctxk1 = deps->at(ctxk_i).as_klass(_oop_recorder);
135 if (ctxk2->is_subtype_of(ctxk1)) {
136 return true; // success, and no need to change
137 } else if (ctxk1->is_subtype_of(ctxk2)) {
138 // new context class fully subsumes previous one
139 deps->at_put(ctxk_i, DepValue(_oop_recorder, ctxk2));
140 return true;
141 } else {
142 return false;
143 }
144 }
145
146 void Dependencies::assert_common_1(DepType dept, DepValue x) {
147 assert(dep_args(dept) == 1, "sanity");
148 log_dependency(dept, x);
149 GrowableArray<DepValue>* deps = _deps[dept];
150
151 // see if the same (or a similar) dep is already recorded
152 if (note_dep_seen(dept, x)) {
153 assert(deps->find(x) >= 0, "sanity");
154 } else {
155 deps->append(x);
156 }
157 }
158
159 void Dependencies::assert_common_2(DepType dept,
160 DepValue x0, DepValue x1) {
161 assert(dep_args(dept) == 2, "sanity");
162 log_dependency(dept, x0, x1);
163 GrowableArray<DepValue>* deps = _deps[dept];
164
165 // see if the same (or a similar) dep is already recorded
166 bool has_ctxk = has_explicit_context_arg(dept);
167 if (has_ctxk) {
168 assert(dep_context_arg(dept) == 0, "sanity");
169 if (note_dep_seen(dept, x1)) {
170 // look in this bucket for redundant assertions
171 const int stride = 2;
172 for (int i = deps->length(); (i -= stride) >= 0; ) {
173 DepValue y1 = deps->at(i+1);
174 if (x1 == y1) { // same subject; check the context
175 if (maybe_merge_ctxk(deps, i+0, x0.as_klass(_oop_recorder))) {
176 return;
177 }
178 }
179 }
180 }
181 } else {
182 assert(dep_implicit_context_arg(dept) == 0, "sanity");
183 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
184 // look in this bucket for redundant assertions
185 const int stride = 2;
186 for (int i = deps->length(); (i -= stride) >= 0; ) {
187 DepValue y0 = deps->at(i+0);
188 DepValue y1 = deps->at(i+1);
189 if (x0 == y0 && x1 == y1) {
190 return;
191 }
192 }
193 }
194 }
195
196 // append the assertion in the correct bucket:
197 deps->append(x0);
198 deps->append(x1);
199 }
200
201 void Dependencies::assert_common_3(DepType dept,
202 Klass* ctxk, DepValue x, DepValue x2) {
203 assert(dep_context_arg(dept) == 0, "sanity");
204 assert(dep_args(dept) == 3, "sanity");
205 log_dependency(dept, DepValue(_oop_recorder, ctxk), x, x2);
206 GrowableArray<DepValue>* deps = _deps[dept];
207
208 // try to normalize an unordered pair:
209 bool swap = false;
210 switch (dept) {
211 case abstract_with_exclusive_concrete_subtypes_2:
212 swap = (x.index() > x2.index() && x.as_klass(_oop_recorder) != ctxk);
213 break;
214 case exclusive_concrete_methods_2:
215 swap = (x.index() > x2.index() && x.as_method(_oop_recorder)->method_holder() != ctxk);
216 break;
217 }
218 if (swap) { DepValue t = x; x = x2; x2 = t; }
219
220 // see if the same (or a similar) dep is already recorded
221 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
222 // look in this bucket for redundant assertions
223 const int stride = 3;
224 for (int i = deps->length(); (i -= stride) >= 0; ) {
225 DepValue y = deps->at(i+1);
226 DepValue y2 = deps->at(i+2);
227 if (x == y && x2 == y2) { // same subjects; check the context
228 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
229 return;
230 }
231 }
232 }
233 }
234 // append the assertion in the correct bucket:
235 deps->append(DepValue(_oop_recorder, ctxk));
236 deps->append(x);
237 deps->append(x2);
238 }
239
240 /// Support for encoding dependencies into an nmethod:
241
242 void Dependencies::copy_to(nmethod* nm) {
243 address beg = nm->dependencies_begin();
244 address end = nm->dependencies_end();
245 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
246 Copy::disjoint_words((HeapWord*) content_bytes(),
247 (HeapWord*) beg,
248 size_in_bytes() / sizeof(HeapWord));
249 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
250 }
251
252 static int sort_dep(Dependencies::DepValue* p1, Dependencies::DepValue* p2, int narg) {
253 for (int i = 0; i < narg; i++) {
254 int diff = p1[i].sort_key() - p2[i].sort_key();
255 if (diff != 0) return diff;
256 }
257 return 0;
258 }
259 static int sort_dep_arg_1(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
260 { return sort_dep(p1, p2, 1); }
261 static int sort_dep_arg_2(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
262 { return sort_dep(p1, p2, 2); }
263 static int sort_dep_arg_3(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
264 { return sort_dep(p1, p2, 3); }
265
266 void Dependencies::sort_all_deps() {
267 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
268 DepType dept = (DepType)deptv;
269 GrowableArray<DepValue>* deps = _deps[dept];
270 if (deps->length() <= 1) continue;
271 switch (dep_args(dept)) {
272 case 1: deps->sort(sort_dep_arg_1, 1); break;
273 case 2: deps->sort(sort_dep_arg_2, 2); break;
274 case 3: deps->sort(sort_dep_arg_3, 3); break;
275 default: ShouldNotReachHere();
276 }
277 }
278 }
279
280 size_t Dependencies::estimate_size_in_bytes() {
281 size_t est_size = 100;
282 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
283 DepType dept = (DepType)deptv;
284 GrowableArray<DepValue>* deps = _deps[dept];
285 est_size += deps->length()*2; // tags and argument(s)
286 }
287 return est_size;
288 }
289
290 Klass* Dependencies::ctxk_encoded_as_null(OopRecorder* oop_recorder, DepType dept, DepValue x) {
291 switch (dept) {
292 case abstract_with_exclusive_concrete_subtypes_2:
293 return x.as_klass(oop_recorder);
294 case unique_concrete_method:
295 case exclusive_concrete_methods_2:
296 return x.as_method(oop_recorder)->method_holder();
297 }
298 return NULL; // let NULL be NULL
299 }
300
301 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
302 assert(must_be_in_vm(), "raw oops here");
303 switch (dept) {
304 case abstract_with_exclusive_concrete_subtypes_2:
305 assert(x->is_klass(), "sanity");
306 return (Klass*) x;
307 case unique_concrete_method:
308 case exclusive_concrete_methods_2:
309 assert(x->is_method(), "sanity");
310 return ((Method*)x)->method_holder();
311 }
312 return NULL; // let NULL be NULL
313 }
314
315 void Dependencies::encode_content_bytes() {
316 sort_all_deps();
317
318 // cast is safe, no deps can overflow INT_MAX
319 CompressedWriteStream bytes((int)estimate_size_in_bytes());
320
321 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
322 DepType dept = (DepType)deptv;
323 GrowableArray<DepValue>* deps = _deps[dept];
324 if (deps->length() == 0) continue;
325 int stride = dep_args(dept);
326 int ctxkj = dep_context_arg(dept); // -1 if no context arg
327 assert(stride > 0, "sanity");
328 for (int i = 0; i < deps->length(); i += stride) {
329 jbyte code_byte = (jbyte)dept;
330 int skipj = -1;
331 if (ctxkj >= 0 && ctxkj+1 < stride) {
332 Klass* ctxk = deps->at(i+ctxkj+0).as_klass(_oop_recorder);
333 DepValue x = deps->at(i+ctxkj+1); // following argument
334 if (ctxk == ctxk_encoded_as_null(_oop_recorder, dept, x)) {
335 skipj = ctxkj; // we win: maybe one less oop to keep track of
336 code_byte |= default_context_type_bit;
337 }
338 }
339 bytes.write_byte(code_byte);
340 for (int j = 0; j < stride; j++) {
341 if (j == skipj) continue;
342 DepValue v = deps->at(i+j);
343 int idx = v.index();
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 DepValue args[max_arg_count];
411 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
412 DepType dept = (DepType)deptv;
413 GrowableArray<DepValue>* 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, DepValue 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_object()) {
438 ciargs[j] = env->get_object(JNIHandles::resolve(args[j].as_object(_oop_recorder)));
439 } else {
440 ciargs[j] = env->get_metadata(args[j].as_metadata(_oop_recorder));
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, DepArgument args[],
449 Klass* witness) {
450 if (log == NULL) {
451 return;
452 }
453 ciEnv* env = ciEnv::current();
454 ciBaseObject* ciargs[max_arg_count];
455 assert(nargs <= max_arg_count, "oob");
456 for (int j = 0; j < nargs; j++) {
457 if (args[j].is_oop()) {
458 ciargs[j] = env->get_object(args[j].oop_value());
459 } else {
460 ciargs[j] = env->get_metadata(args[j].metadata_value());
461 }
462 }
463 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
464 }
465
466 void Dependencies::write_dependency_to(CompileLog* log,
467 DepType dept,
468 int nargs, ciBaseObject* args[],
469 Klass* witness) {
470 if (log == NULL) return;
471 assert(nargs <= max_arg_count, "oob");
472 int argids[max_arg_count];
473 int ctxkj = dep_context_arg(dept); // -1 if no context arg
474 int j;
475 for (j = 0; j < nargs; j++) {
476 if (args[j]->is_object()) {
477 argids[j] = log->identify(args[j]->as_object());
478 } else {
479 argids[j] = log->identify(args[j]->as_metadata());
480 }
481 }
482 if (witness != NULL) {
483 log->begin_elem("dependency_failed");
484 } else {
485 log->begin_elem("dependency");
486 }
487 log->print(" type='%s'", dep_name(dept));
488 if (ctxkj >= 0) {
489 log->print(" ctxk='%d'", argids[ctxkj]);
490 }
491 // write remaining arguments, if any.
492 for (j = 0; j < nargs; j++) {
493 if (j == ctxkj) continue; // already logged
494 if (j == 1) {
495 log->print( " x='%d'", argids[j]);
496 } else {
497 log->print(" x%d='%d'", j, argids[j]);
498 }
499 }
500 if (witness != NULL) {
501 log->object("witness", witness);
502 log->stamp();
503 }
504 log->end_elem();
505 }
506
507 void Dependencies::write_dependency_to(xmlStream* xtty,
508 DepType dept,
509 int nargs, DepArgument args[],
510 Klass* witness) {
511 if (xtty == NULL) return;
512 ttyLocker ttyl;
513 int ctxkj = dep_context_arg(dept); // -1 if no context arg
514 if (witness != NULL) {
515 xtty->begin_elem("dependency_failed");
516 } else {
517 xtty->begin_elem("dependency");
518 }
519 xtty->print(" type='%s'", dep_name(dept));
520 if (ctxkj >= 0) {
521 xtty->object("ctxk", args[ctxkj].metadata_value());
522 }
523 // write remaining arguments, if any.
524 for (int j = 0; j < nargs; j++) {
525 if (j == ctxkj) continue; // already logged
526 if (j == 1) {
527 if (args[j].is_oop()) {
528 xtty->object("x", args[j].oop_value());
529 } else {
530 xtty->object("x", args[j].metadata_value());
531 }
532 } else {
533 char xn[10]; sprintf(xn, "x%d", j);
534 if (args[j].is_oop()) {
535 xtty->object(xn, args[j].oop_value());
536 } else {
537 xtty->object(xn, args[j].metadata_value());
538 }
539 }
540 }
541 if (witness != NULL) {
542 xtty->object("witness", witness);
543 xtty->stamp();
544 }
545 xtty->end_elem();
546 }
547
548 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[],
549 Klass* witness) {
550 ResourceMark rm;
551 ttyLocker ttyl; // keep the following output all in one block
552 tty->print_cr("%s of type %s",
553 (witness == NULL)? "Dependency": "Failed dependency",
554 dep_name(dept));
555 // print arguments
556 int ctxkj = dep_context_arg(dept); // -1 if no context arg
557 for (int j = 0; j < nargs; j++) {
558 DepArgument arg = args[j];
559 bool put_star = false;
560 if (arg.is_null()) continue;
561 const char* what;
562 if (j == ctxkj) {
563 assert(arg.is_metadata(), "must be");
564 what = "context";
565 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
566 } else if (arg.is_method()) {
567 what = "method ";
568 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
569 } else if (arg.is_klass()) {
570 what = "class ";
571 } else {
572 what = "object ";
573 }
574 tty->print(" %s = %s", what, (put_star? "*": ""));
575 if (arg.is_klass())
576 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
577 else if (arg.is_method())
578 ((Method*)arg.metadata_value())->print_value();
579 else
580 ShouldNotReachHere(); // Provide impl for this type.
581 tty->cr();
582 }
583 if (witness != NULL) {
584 bool put_star = !Dependencies::is_concrete_klass(witness);
585 tty->print_cr(" witness = %s%s",
586 (put_star? "*": ""),
587 witness->external_name());
588 }
589 }
590
591 void Dependencies::DepStream::log_dependency(Klass* witness) {
592 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
593 ResourceMark rm;
594 int nargs = argument_count();
595 DepArgument args[max_arg_count];
596 for (int j = 0; j < nargs; j++) {
597 if (type() == call_site_target_value) {
598 args[j] = argument_oop(j);
599 } else {
600 args[j] = argument(j);
601 }
602 }
603 if (_deps != NULL && _deps->log() != NULL) {
604 Dependencies::write_dependency_to(_deps->log(),
605 type(), nargs, args, witness);
606 } else {
607 Dependencies::write_dependency_to(xtty,
608 type(), nargs, args, witness);
609 }
610 }
611
612 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
613 int nargs = argument_count();
614 DepArgument args[max_arg_count];
615 for (int j = 0; j < nargs; j++) {
616 args[j] = argument(j);
617 }
618 Dependencies::print_dependency(type(), nargs, args, witness);
619 if (verbose) {
620 if (_code != NULL) {
621 tty->print(" code: ");
622 _code->print_value_on(tty);
623 tty->cr();
624 }
625 }
626 }
627
628
629 /// Dependency stream support (decodes dependencies from an nmethod):
630
631 #ifdef ASSERT
632 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
633 assert(must_be_in_vm(), "raw oops here");
634 _byte_limit = byte_limit;
635 _type = (DepType)(end_marker-1); // defeat "already at end" assert
636 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
637 }
638 #endif //ASSERT
639
640 bool Dependencies::DepStream::next() {
641 assert(_type != end_marker, "already at end");
642 if (_bytes.position() == 0 && _code != NULL
643 && _code->dependencies_size() == 0) {
644 // Method has no dependencies at all.
645 return false;
646 }
647 int code_byte = (_bytes.read_byte() & 0xFF);
648 if (code_byte == end_marker) {
649 DEBUG_ONLY(_type = end_marker);
650 return false;
651 } else {
652 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
653 code_byte -= ctxk_bit;
654 DepType dept = (DepType)code_byte;
655 _type = dept;
656 Dependencies::check_valid_dependency_type(dept);
657 int stride = _dep_args[dept];
658 assert(stride == dep_args(dept), "sanity");
659 int skipj = -1;
660 if (ctxk_bit != 0) {
661 skipj = 0; // currently the only context argument is at zero
662 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
663 }
664 for (int j = 0; j < stride; j++) {
665 _xi[j] = (j == skipj)? 0: _bytes.read_int();
666 }
667 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
668 return true;
669 }
670 }
671
672 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
673 Metadata* o = NULL;
674 if (_code != NULL) {
675 o = _code->metadata_at(i);
676 } else {
677 o = _deps->oop_recorder()->metadata_at(i);
678 }
679 assert(o == NULL || o->is_metaspace_object(),
680 err_msg("Should be metadata " PTR_FORMAT, o));
681 return o;
682 }
683
684 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
685 return (_code != NULL)
686 ? _code->oop_at(i)
687 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
688 }
689
690 Metadata* Dependencies::DepStream::argument(int i) {
691 Metadata* result = recorded_metadata_at(argument_index(i));
692
693 if (result == NULL) { // Explicit context argument can be compressed
694 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
695 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
696 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
697 }
698 }
699
700 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
701 return result;
702 }
703
704 oop Dependencies::DepStream::argument_oop(int i) {
705 oop result = recorded_oop_at(argument_index(i));
706 assert(result == NULL || result->is_oop(), "must be");
707 return result;
708 }
709
710 Klass* Dependencies::DepStream::context_type() {
711 assert(must_be_in_vm(), "raw oops here");
712
713 // Most dependencies have an explicit context type argument.
714 {
715 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
716 if (ctxkj >= 0) {
717 Metadata* k = argument(ctxkj);
718 assert(k != NULL && k->is_klass(), "type check");
719 return (Klass*)k;
720 }
721 }
722
723 // Some dependencies are using the klass of the first object
724 // argument as implicit context type (e.g. call_site_target_value).
725 {
726 int ctxkj = dep_implicit_context_arg(type());
727 if (ctxkj >= 0) {
728 Klass* k = argument_oop(ctxkj)->klass();
729 assert(k != NULL && k->is_klass(), "type check");
730 return (Klass*) k;
731 }
732 }
733
734 // And some dependencies don't have a context type at all,
735 // e.g. evol_method.
736 return NULL;
737 }
738
739 /// Checking dependencies:
740
741 // This hierarchy walker inspects subtypes of a given type,
742 // trying to find a "bad" class which breaks a dependency.
743 // Such a class is called a "witness" to the broken dependency.
744 // While searching around, we ignore "participants", which
745 // are already known to the dependency.
746 class ClassHierarchyWalker {
747 public:
748 enum { PARTICIPANT_LIMIT = 3 };
749
750 private:
751 // optional method descriptor to check for:
752 Symbol* _name;
753 Symbol* _signature;
754
755 // special classes which are not allowed to be witnesses:
756 Klass* _participants[PARTICIPANT_LIMIT+1];
757 int _num_participants;
758
759 // cache of method lookups
760 Method* _found_methods[PARTICIPANT_LIMIT+1];
761
762 // if non-zero, tells how many witnesses to convert to participants
763 int _record_witnesses;
764
765 void initialize(Klass* participant) {
766 _record_witnesses = 0;
767 _participants[0] = participant;
768 _found_methods[0] = NULL;
769 _num_participants = 0;
770 if (participant != NULL) {
771 // Terminating NULL.
772 _participants[1] = NULL;
773 _found_methods[1] = NULL;
774 _num_participants = 1;
775 }
776 }
777
778 void initialize_from_method(Method* m) {
779 assert(m != NULL && m->is_method(), "sanity");
780 _name = m->name();
781 _signature = m->signature();
782 }
783
784 public:
785 // The walker is initialized to recognize certain methods and/or types
786 // as friendly participants.
787 ClassHierarchyWalker(Klass* participant, Method* m) {
788 initialize_from_method(m);
789 initialize(participant);
790 }
791 ClassHierarchyWalker(Method* m) {
792 initialize_from_method(m);
793 initialize(NULL);
794 }
795 ClassHierarchyWalker(Klass* participant = NULL) {
796 _name = NULL;
797 _signature = NULL;
798 initialize(participant);
799 }
800
801 // This is common code for two searches: One for concrete subtypes,
802 // the other for concrete method implementations and overrides.
803 bool doing_subtype_search() {
804 return _name == NULL;
805 }
806
807 int num_participants() { return _num_participants; }
808 Klass* participant(int n) {
809 assert((uint)n <= (uint)_num_participants, "oob");
810 return _participants[n];
811 }
812
813 // Note: If n==num_participants, returns NULL.
814 Method* found_method(int n) {
815 assert((uint)n <= (uint)_num_participants, "oob");
816 Method* fm = _found_methods[n];
817 assert(n == _num_participants || fm != NULL, "proper usage");
818 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
819 return fm;
820 }
821
822 #ifdef ASSERT
823 // Assert that m is inherited into ctxk, without intervening overrides.
824 // (May return true even if this is not true, in corner cases where we punt.)
825 bool check_method_context(Klass* ctxk, Method* m) {
826 if (m->method_holder() == ctxk)
827 return true; // Quick win.
828 if (m->is_private())
829 return false; // Quick lose. Should not happen.
830 if (!(m->is_public() || m->is_protected()))
831 // The override story is complex when packages get involved.
832 return true; // Must punt the assertion to true.
833 Klass* k = ctxk;
834 Method* lm = k->lookup_method(m->name(), m->signature());
835 if (lm == NULL && k->oop_is_instance()) {
836 // It might be an interface method
837 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
838 m->signature());
839 }
840 if (lm == m)
841 // Method m is inherited into ctxk.
842 return true;
843 if (lm != NULL) {
844 if (!(lm->is_public() || lm->is_protected())) {
845 // Method is [package-]private, so the override story is complex.
846 return true; // Must punt the assertion to true.
847 }
848 if (lm->is_static()) {
849 // Static methods don't override non-static so punt
850 return true;
851 }
852 if ( !Dependencies::is_concrete_method(lm)
853 && !Dependencies::is_concrete_method(m)
854 && lm->method_holder()->is_subtype_of(m->method_holder()))
855 // Method m is overridden by lm, but both are non-concrete.
856 return true;
857 }
858 ResourceMark rm;
859 tty->print_cr("Dependency method not found in the associated context:");
860 tty->print_cr(" context = %s", ctxk->external_name());
861 tty->print( " method = "); m->print_short_name(tty); tty->cr();
862 if (lm != NULL) {
863 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
864 }
865 return false;
866 }
867 #endif
868
869 void add_participant(Klass* participant) {
870 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
871 int np = _num_participants++;
872 _participants[np] = participant;
873 _participants[np+1] = NULL;
874 _found_methods[np+1] = NULL;
875 }
876
877 void record_witnesses(int add) {
878 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
879 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
880 _record_witnesses = add;
881 }
882
883 bool is_witness(Klass* k) {
884 if (doing_subtype_search()) {
885 return Dependencies::is_concrete_klass(k);
886 } else {
887 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
888 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
889 _found_methods[_num_participants] = m;
890 // Note: If add_participant(k) is called,
891 // the method m will already be memoized for it.
892 return true;
893 }
894 }
895
896 bool is_participant(Klass* k) {
897 if (k == _participants[0]) {
898 return true;
899 } else if (_num_participants <= 1) {
900 return false;
901 } else {
902 return in_list(k, &_participants[1]);
903 }
904 }
905 bool ignore_witness(Klass* witness) {
906 if (_record_witnesses == 0) {
907 return false;
908 } else {
909 --_record_witnesses;
910 add_participant(witness);
911 return true;
912 }
913 }
914 static bool in_list(Klass* x, Klass** list) {
915 for (int i = 0; ; i++) {
916 Klass* y = list[i];
917 if (y == NULL) break;
918 if (y == x) return true;
919 }
920 return false; // not in list
921 }
922
923 private:
924 // the actual search method:
925 Klass* find_witness_anywhere(Klass* context_type,
926 bool participants_hide_witnesses,
927 bool top_level_call = true);
928 // the spot-checking version:
929 Klass* find_witness_in(KlassDepChange& changes,
930 Klass* context_type,
931 bool participants_hide_witnesses);
932 public:
933 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
934 assert(doing_subtype_search(), "must set up a subtype search");
935 // When looking for unexpected concrete types,
936 // do not look beneath expected ones.
937 const bool participants_hide_witnesses = true;
938 // CX > CC > C' is OK, even if C' is new.
939 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
940 if (changes != NULL) {
941 return find_witness_in(*changes, context_type, participants_hide_witnesses);
942 } else {
943 return find_witness_anywhere(context_type, participants_hide_witnesses);
944 }
945 }
946 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
947 assert(!doing_subtype_search(), "must set up a method definer search");
948 // When looking for unexpected concrete methods,
949 // look beneath expected ones, to see if there are overrides.
950 const bool participants_hide_witnesses = true;
951 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
952 if (changes != NULL) {
953 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
954 } else {
955 return find_witness_anywhere(context_type, !participants_hide_witnesses);
956 }
957 }
958 };
959
960 #ifndef PRODUCT
961 static int deps_find_witness_calls = 0;
962 static int deps_find_witness_steps = 0;
963 static int deps_find_witness_recursions = 0;
964 static int deps_find_witness_singles = 0;
965 static int deps_find_witness_print = 0; // set to -1 to force a final print
966 static bool count_find_witness_calls() {
967 if (TraceDependencies || LogCompilation) {
968 int pcount = deps_find_witness_print + 1;
969 bool final_stats = (pcount == 0);
970 bool initial_call = (pcount == 1);
971 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
972 if (pcount < 0) pcount = 1; // crude overflow protection
973 deps_find_witness_print = pcount;
974 if (VerifyDependencies && initial_call) {
975 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
976 }
977 if (occasional_print || final_stats) {
978 // Every now and then dump a little info about dependency searching.
979 if (xtty != NULL) {
980 ttyLocker ttyl;
981 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
982 deps_find_witness_calls,
983 deps_find_witness_steps,
984 deps_find_witness_recursions,
985 deps_find_witness_singles);
986 }
987 if (final_stats || (TraceDependencies && WizardMode)) {
988 ttyLocker ttyl;
989 tty->print_cr("Dependency check (find_witness) "
990 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
991 deps_find_witness_calls,
992 deps_find_witness_steps,
993 (double)deps_find_witness_steps / deps_find_witness_calls,
994 deps_find_witness_recursions,
995 deps_find_witness_singles);
996 }
997 }
998 return true;
999 }
1000 return false;
1001 }
1002 #else
1003 #define count_find_witness_calls() (0)
1004 #endif //PRODUCT
1005
1006
1007 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1008 Klass* context_type,
1009 bool participants_hide_witnesses) {
1010 assert(changes.involves_context(context_type), "irrelevant dependency");
1011 Klass* new_type = changes.new_type();
1012
1013 (void)count_find_witness_calls();
1014 NOT_PRODUCT(deps_find_witness_singles++);
1015
1016 // Current thread must be in VM (not native mode, as in CI):
1017 assert(must_be_in_vm(), "raw oops here");
1018 // Must not move the class hierarchy during this check:
1019 assert_locked_or_safepoint(Compile_lock);
1020
1021 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1022 if (nof_impls > 1) {
1023 // Avoid this case: *I.m > { A.m, C }; B.m > C
1024 // %%% Until this is fixed more systematically, bail out.
1025 // See corresponding comment in find_witness_anywhere.
1026 return context_type;
1027 }
1028
1029 assert(!is_participant(new_type), "only old classes are participants");
1030 if (participants_hide_witnesses) {
1031 // If the new type is a subtype of a participant, we are done.
1032 for (int i = 0; i < num_participants(); i++) {
1033 Klass* part = participant(i);
1034 if (part == NULL) continue;
1035 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1036 "correct marking of participants, b/c new_type is unique");
1037 if (changes.involves_context(part)) {
1038 // new guy is protected from this check by previous participant
1039 return NULL;
1040 }
1041 }
1042 }
1043
1044 if (is_witness(new_type) &&
1045 !ignore_witness(new_type)) {
1046 return new_type;
1047 }
1048
1049 return NULL;
1050 }
1051
1052
1053 // Walk hierarchy under a context type, looking for unexpected types.
1054 // Do not report participant types, and recursively walk beneath
1055 // them only if participants_hide_witnesses is false.
1056 // If top_level_call is false, skip testing the context type,
1057 // because the caller has already considered it.
1058 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1059 bool participants_hide_witnesses,
1060 bool top_level_call) {
1061 // Current thread must be in VM (not native mode, as in CI):
1062 assert(must_be_in_vm(), "raw oops here");
1063 // Must not move the class hierarchy during this check:
1064 assert_locked_or_safepoint(Compile_lock);
1065
1066 bool do_counts = count_find_witness_calls();
1067
1068 // Check the root of the sub-hierarchy first.
1069 if (top_level_call) {
1070 if (do_counts) {
1071 NOT_PRODUCT(deps_find_witness_calls++);
1072 NOT_PRODUCT(deps_find_witness_steps++);
1073 }
1074 if (is_participant(context_type)) {
1075 if (participants_hide_witnesses) return NULL;
1076 // else fall through to search loop...
1077 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1078 // The context is an abstract class or interface, to start with.
1079 return context_type;
1080 }
1081 }
1082
1083 // Now we must check each implementor and each subclass.
1084 // Use a short worklist to avoid blowing the stack.
1085 // Each worklist entry is a *chain* of subklass siblings to process.
1086 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1087 Klass* chains[CHAINMAX];
1088 int chaini = 0; // index into worklist
1089 Klass* chain; // scratch variable
1090 #define ADD_SUBCLASS_CHAIN(k) { \
1091 assert(chaini < CHAINMAX, "oob"); \
1092 chain = InstanceKlass::cast(k)->subklass(); \
1093 if (chain != NULL) chains[chaini++] = chain; }
1094
1095 // Look for non-abstract subclasses.
1096 // (Note: Interfaces do not have subclasses.)
1097 ADD_SUBCLASS_CHAIN(context_type);
1098
1099 // If it is an interface, search its direct implementors.
1100 // (Their subclasses are additional indirect implementors.
1101 // See InstanceKlass::add_implementor.)
1102 // (Note: nof_implementors is always zero for non-interfaces.)
1103 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1104 if (nof_impls > 1) {
1105 // Avoid this case: *I.m > { A.m, C }; B.m > C
1106 // Here, I.m has 2 concrete implementations, but m appears unique
1107 // as A.m, because the search misses B.m when checking C.
1108 // The inherited method B.m was getting missed by the walker
1109 // when interface 'I' was the starting point.
1110 // %%% Until this is fixed more systematically, bail out.
1111 // (Old CHA had the same limitation.)
1112 return context_type;
1113 }
1114 if (nof_impls > 0) {
1115 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1116 assert(impl != NULL, "just checking");
1117 // If impl is the same as the context_type, then more than one
1118 // implementor has seen. No exact info in this case.
1119 if (impl == context_type) {
1120 return context_type; // report an inexact witness to this sad affair
1121 }
1122 if (do_counts)
1123 { NOT_PRODUCT(deps_find_witness_steps++); }
1124 if (is_participant(impl)) {
1125 if (!participants_hide_witnesses) {
1126 ADD_SUBCLASS_CHAIN(impl);
1127 }
1128 } else if (is_witness(impl) && !ignore_witness(impl)) {
1129 return impl;
1130 } else {
1131 ADD_SUBCLASS_CHAIN(impl);
1132 }
1133 }
1134
1135 // Recursively process each non-trivial sibling chain.
1136 while (chaini > 0) {
1137 Klass* chain = chains[--chaini];
1138 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1139 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1140 if (is_participant(sub)) {
1141 if (participants_hide_witnesses) continue;
1142 // else fall through to process this guy's subclasses
1143 } else if (is_witness(sub) && !ignore_witness(sub)) {
1144 return sub;
1145 }
1146 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1147 // Fast path. (Partially disabled if VerifyDependencies.)
1148 ADD_SUBCLASS_CHAIN(sub);
1149 } else {
1150 // Worklist overflow. Do a recursive call. Should be rare.
1151 // The recursive call will have its own worklist, of course.
1152 // (Note that sub has already been tested, so that there is
1153 // no need for the recursive call to re-test. That's handy,
1154 // since the recursive call sees sub as the context_type.)
1155 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1156 Klass* witness = find_witness_anywhere(sub,
1157 participants_hide_witnesses,
1158 /*top_level_call=*/ false);
1159 if (witness != NULL) return witness;
1160 }
1161 }
1162 }
1163
1164 // No witness found. The dependency remains unbroken.
1165 return NULL;
1166 #undef ADD_SUBCLASS_CHAIN
1167 }
1168
1169
1170 bool Dependencies::is_concrete_klass(Klass* k) {
1171 if (k->is_abstract()) return false;
1172 // %%% We could treat classes which are concrete but
1173 // have not yet been instantiated as virtually abstract.
1174 // This would require a deoptimization barrier on first instantiation.
1175 //if (k->is_not_instantiated()) return false;
1176 return true;
1177 }
1178
1179 bool Dependencies::is_concrete_method(Method* m) {
1180 // Statics are irrelevant to virtual call sites.
1181 if (m->is_static()) return false;
1182
1183 // We could also return false if m does not yet appear to be
1184 // executed, if the VM version supports this distinction also.
1185 return !m->is_abstract() &&
1186 !InstanceKlass::cast(m->method_holder())->is_interface();
1187 // TODO: investigate whether default methods should be
1188 // considered as "concrete" in this situation. For now they
1189 // are not.
1190 }
1191
1192
1193 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1194 if (k->is_interface()) return NULL;
1195 if (k->has_finalizer()) return k;
1196 k = k->subklass();
1197 while (k != NULL) {
1198 Klass* result = find_finalizable_subclass(k);
1199 if (result != NULL) return result;
1200 k = k->next_sibling();
1201 }
1202 return NULL;
1203 }
1204
1205
1206 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1207 if (k->is_abstract()) return false;
1208 // We could also return false if k does not yet appear to be
1209 // instantiated, if the VM version supports this distinction also.
1210 //if (k->is_not_instantiated()) return false;
1211 return true;
1212 }
1213
1214 bool Dependencies::is_concrete_method(ciMethod* m) {
1215 // Statics are irrelevant to virtual call sites.
1216 if (m->is_static()) return false;
1217
1218 // We could also return false if m does not yet appear to be
1219 // executed, if the VM version supports this distinction also.
1220 return !m->is_abstract();
1221 }
1222
1223
1224 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1225 return k->has_finalizable_subclass();
1226 }
1227
1228
1229 // Any use of the contents (bytecodes) of a method must be
1230 // marked by an "evol_method" dependency, if those contents
1231 // can change. (Note: A method is always dependent on itself.)
1232 Klass* Dependencies::check_evol_method(Method* m) {
1233 assert(must_be_in_vm(), "raw oops here");
1234 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1235 // Or is there a now a breakpoint?
1236 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1237 if (m->is_old()
1238 || m->number_of_breakpoints() > 0) {
1239 return m->method_holder();
1240 } else {
1241 return NULL;
1242 }
1243 }
1244
1245 // This is a strong assertion: It is that the given type
1246 // has no subtypes whatever. It is most useful for
1247 // optimizing checks on reflected types or on array types.
1248 // (Checks on types which are derived from real instances
1249 // can be optimized more strongly than this, because we
1250 // know that the checked type comes from a concrete type,
1251 // and therefore we can disregard abstract types.)
1252 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1253 assert(must_be_in_vm(), "raw oops here");
1254 assert_locked_or_safepoint(Compile_lock);
1255 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1256 Klass* sub = ctx->subklass();
1257 if (sub != NULL) {
1258 return sub;
1259 } else if (ctx->nof_implementors() != 0) {
1260 // if it is an interface, it must be unimplemented
1261 // (if it is not an interface, nof_implementors is always zero)
1262 Klass* impl = ctx->implementor();
1263 assert(impl != NULL, "must be set");
1264 return impl;
1265 } else {
1266 return NULL;
1267 }
1268 }
1269
1270 // Test the assertion that conck is the only concrete subtype* of ctxk.
1271 // The type conck itself is allowed to have have further concrete subtypes.
1272 // This allows the compiler to narrow occurrences of ctxk by conck,
1273 // when dealing with the types of actual instances.
1274 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1275 Klass* conck,
1276 KlassDepChange* changes) {
1277 ClassHierarchyWalker wf(conck);
1278 return wf.find_witness_subtype(ctxk, changes);
1279 }
1280
1281 // If a non-concrete class has no concrete subtypes, it is not (yet)
1282 // instantiatable. This can allow the compiler to make some paths go
1283 // dead, if they are gated by a test of the type.
1284 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1285 KlassDepChange* changes) {
1286 // Find any concrete subtype, with no participants:
1287 ClassHierarchyWalker wf;
1288 return wf.find_witness_subtype(ctxk, changes);
1289 }
1290
1291
1292 // If a concrete class has no concrete subtypes, it can always be
1293 // exactly typed. This allows the use of a cheaper type test.
1294 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1295 KlassDepChange* changes) {
1296 // Find any concrete subtype, with only the ctxk as participant:
1297 ClassHierarchyWalker wf(ctxk);
1298 return wf.find_witness_subtype(ctxk, changes);
1299 }
1300
1301
1302 // Find the unique concrete proper subtype of ctxk, or NULL if there
1303 // is more than one concrete proper subtype. If there are no concrete
1304 // proper subtypes, return ctxk itself, whether it is concrete or not.
1305 // The returned subtype is allowed to have have further concrete subtypes.
1306 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1307 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1308 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1309 wf.record_witnesses(1); // Record one other witness when walking.
1310 Klass* wit = wf.find_witness_subtype(ctxk);
1311 if (wit != NULL) return NULL; // Too many witnesses.
1312 Klass* conck = wf.participant(0);
1313 if (conck == NULL) {
1314 #ifndef PRODUCT
1315 // Make sure the dependency mechanism will pass this discovery:
1316 if (VerifyDependencies) {
1317 // Turn off dependency tracing while actually testing deps.
1318 FlagSetting fs(TraceDependencies, false);
1319 if (!Dependencies::is_concrete_klass(ctxk)) {
1320 guarantee(NULL ==
1321 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1322 "verify dep.");
1323 } else {
1324 guarantee(NULL ==
1325 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1326 "verify dep.");
1327 }
1328 }
1329 #endif //PRODUCT
1330 return ctxk; // Return ctxk as a flag for "no subtypes".
1331 } else {
1332 #ifndef PRODUCT
1333 // Make sure the dependency mechanism will pass this discovery:
1334 if (VerifyDependencies) {
1335 // Turn off dependency tracing while actually testing deps.
1336 FlagSetting fs(TraceDependencies, false);
1337 if (!Dependencies::is_concrete_klass(ctxk)) {
1338 guarantee(NULL == (void *)
1339 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1340 "verify dep.");
1341 }
1342 }
1343 #endif //PRODUCT
1344 return conck;
1345 }
1346 }
1347
1348 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1349 // except possibly for further subtypes of k[12] themselves.
1350 // The context type must be abstract. The types k1 and k2 are themselves
1351 // allowed to have further concrete subtypes.
1352 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1353 Klass* ctxk,
1354 Klass* k1,
1355 Klass* k2,
1356 KlassDepChange* changes) {
1357 ClassHierarchyWalker wf;
1358 wf.add_participant(k1);
1359 wf.add_participant(k2);
1360 return wf.find_witness_subtype(ctxk, changes);
1361 }
1362
1363 // Search ctxk for concrete implementations. If there are klen or fewer,
1364 // pack them into the given array and return the number.
1365 // Otherwise, return -1, meaning the given array would overflow.
1366 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1367 // In this search, if ctxk is concrete, it will be reported alone.
1368 // For any type CC reported, no proper subtypes of CC will be reported.
1369 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1370 int klen,
1371 Klass* karray[]) {
1372 ClassHierarchyWalker wf;
1373 wf.record_witnesses(klen);
1374 Klass* wit = wf.find_witness_subtype(ctxk);
1375 if (wit != NULL) return -1; // Too many witnesses.
1376 int num = wf.num_participants();
1377 assert(num <= klen, "oob");
1378 // Pack the result array with the good news.
1379 for (int i = 0; i < num; i++)
1380 karray[i] = wf.participant(i);
1381 #ifndef PRODUCT
1382 // Make sure the dependency mechanism will pass this discovery:
1383 if (VerifyDependencies) {
1384 // Turn off dependency tracing while actually testing deps.
1385 FlagSetting fs(TraceDependencies, false);
1386 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1387 case -1: // ctxk was itself concrete
1388 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1389 break;
1390 case 0:
1391 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1392 "verify dep.");
1393 break;
1394 case 1:
1395 guarantee(NULL == (void *)
1396 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1397 "verify dep.");
1398 break;
1399 case 2:
1400 guarantee(NULL == (void *)
1401 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1402 karray[0],
1403 karray[1]),
1404 "verify dep.");
1405 break;
1406 default:
1407 ShouldNotReachHere(); // klen > 2 yet supported
1408 }
1409 }
1410 #endif //PRODUCT
1411 return num;
1412 }
1413
1414 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1415 // Otherwise, return a class that contains an interfering method.
1416 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1417 KlassDepChange* changes) {
1418 // Here is a missing optimization: If uniqm->is_final(),
1419 // we don't really need to search beneath it for overrides.
1420 // This is probably not important, since we don't use dependencies
1421 // to track final methods. (They can't be "definalized".)
1422 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1423 return wf.find_witness_definer(ctxk, changes);
1424 }
1425
1426 // Find the set of all non-abstract methods under ctxk that match m.
1427 // (The method m must be defined or inherited in ctxk.)
1428 // Include m itself in the set, unless it is abstract.
1429 // If this set has exactly one element, return that element.
1430 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1431 ClassHierarchyWalker wf(m);
1432 assert(wf.check_method_context(ctxk, m), "proper context");
1433 wf.record_witnesses(1);
1434 Klass* wit = wf.find_witness_definer(ctxk);
1435 if (wit != NULL) return NULL; // Too many witnesses.
1436 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1437 if (Dependencies::is_concrete_method(m)) {
1438 if (fm == NULL) {
1439 // It turns out that m was always the only implementation.
1440 fm = m;
1441 } else if (fm != m) {
1442 // Two conflicting implementations after all.
1443 // (This can happen if m is inherited into ctxk and fm overrides it.)
1444 return NULL;
1445 }
1446 }
1447 #ifndef PRODUCT
1448 // Make sure the dependency mechanism will pass this discovery:
1449 if (VerifyDependencies && fm != NULL) {
1450 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1451 "verify dep.");
1452 }
1453 #endif //PRODUCT
1454 return fm;
1455 }
1456
1457 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1458 Method* m1,
1459 Method* m2,
1460 KlassDepChange* changes) {
1461 ClassHierarchyWalker wf(m1);
1462 wf.add_participant(m1->method_holder());
1463 wf.add_participant(m2->method_holder());
1464 return wf.find_witness_definer(ctxk, changes);
1465 }
1466
1467 // Find the set of all non-abstract methods under ctxk that match m[0].
1468 // (The method m[0] must be defined or inherited in ctxk.)
1469 // Include m itself in the set, unless it is abstract.
1470 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1471 // (The length may be zero if no concrete methods are found anywhere.)
1472 // If there are too many concrete methods to fit in marray, return -1.
1473 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1474 int mlen,
1475 Method* marray[]) {
1476 Method* m0 = marray[0];
1477 ClassHierarchyWalker wf(m0);
1478 assert(wf.check_method_context(ctxk, m0), "proper context");
1479 wf.record_witnesses(mlen);
1480 bool participants_hide_witnesses = true;
1481 Klass* wit = wf.find_witness_definer(ctxk);
1482 if (wit != NULL) return -1; // Too many witnesses.
1483 int num = wf.num_participants();
1484 assert(num <= mlen, "oob");
1485 // Keep track of whether m is also part of the result set.
1486 int mfill = 0;
1487 assert(marray[mfill] == m0, "sanity");
1488 if (Dependencies::is_concrete_method(m0))
1489 mfill++; // keep m0 as marray[0], the first result
1490 for (int i = 0; i < num; i++) {
1491 Method* fm = wf.found_method(i);
1492 if (fm == m0) continue; // Already put this guy in the list.
1493 if (mfill == mlen) {
1494 return -1; // Oops. Too many methods after all!
1495 }
1496 marray[mfill++] = fm;
1497 }
1498 #ifndef PRODUCT
1499 // Make sure the dependency mechanism will pass this discovery:
1500 if (VerifyDependencies) {
1501 // Turn off dependency tracing while actually testing deps.
1502 FlagSetting fs(TraceDependencies, false);
1503 switch (mfill) {
1504 case 1:
1505 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1506 "verify dep.");
1507 break;
1508 case 2:
1509 guarantee(NULL == (void *)
1510 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1511 "verify dep.");
1512 break;
1513 default:
1514 ShouldNotReachHere(); // mlen > 2 yet supported
1515 }
1516 }
1517 #endif //PRODUCT
1518 return mfill;
1519 }
1520
1521
1522 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1523 Klass* search_at = ctxk;
1524 if (changes != NULL)
1525 search_at = changes->new_type(); // just look at the new bit
1526 return find_finalizable_subclass(search_at);
1527 }
1528
1529
1530 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1531 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1532 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1533 if (changes == NULL) {
1534 // Validate all CallSites
1535 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1536 return call_site->klass(); // assertion failed
1537 } else {
1538 // Validate the given CallSite
1539 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1540 assert(method_handle != changes->method_handle(), "must be");
1541 return call_site->klass(); // assertion failed
1542 }
1543 }
1544 return NULL; // assertion still valid
1545 }
1546
1547
1548 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1549 if (witness != NULL) {
1550 if (TraceDependencies) {
1551 print_dependency(witness, /*verbose=*/ true);
1552 }
1553 // The following is a no-op unless logging is enabled:
1554 log_dependency(witness);
1555 }
1556 }
1557
1558
1559 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1560 assert_locked_or_safepoint(Compile_lock);
1561 Dependencies::check_valid_dependency_type(type());
1562
1563 Klass* witness = NULL;
1564 switch (type()) {
1565 case evol_method:
1566 witness = check_evol_method(method_argument(0));
1567 break;
1568 case leaf_type:
1569 witness = check_leaf_type(context_type());
1570 break;
1571 case abstract_with_unique_concrete_subtype:
1572 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1573 break;
1574 case abstract_with_no_concrete_subtype:
1575 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1576 break;
1577 case concrete_with_no_concrete_subtype:
1578 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1579 break;
1580 case unique_concrete_method:
1581 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1582 break;
1583 case abstract_with_exclusive_concrete_subtypes_2:
1584 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1585 break;
1586 case exclusive_concrete_methods_2:
1587 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1588 break;
1589 case no_finalizable_subclasses:
1590 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1591 break;
1592 default:
1593 witness = NULL;
1594 break;
1595 }
1596 trace_and_log_witness(witness);
1597 return witness;
1598 }
1599
1600
1601 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1602 assert_locked_or_safepoint(Compile_lock);
1603 Dependencies::check_valid_dependency_type(type());
1604
1605 Klass* witness = NULL;
1606 switch (type()) {
1607 case call_site_target_value:
1608 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1609 break;
1610 default:
1611 witness = NULL;
1612 break;
1613 }
1614 trace_and_log_witness(witness);
1615 return witness;
1616 }
1617
1618
1619 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1620 // Handle klass dependency
1621 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1622 return check_klass_dependency(changes.as_klass_change());
1623
1624 // Handle CallSite dependency
1625 if (changes.is_call_site_change())
1626 return check_call_site_dependency(changes.as_call_site_change());
1627
1628 // irrelevant dependency; skip it
1629 return NULL;
1630 }
1631
1632
1633 void DepChange::print() {
1634 int nsup = 0, nint = 0;
1635 for (ContextStream str(*this); str.next(); ) {
1636 Klass* k = str.klass();
1637 switch (str.change_type()) {
1638 case Change_new_type:
1639 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1640 break;
1641 case Change_new_sub:
1642 if (!WizardMode) {
1643 ++nsup;
1644 } else {
1645 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1646 }
1647 break;
1648 case Change_new_impl:
1649 if (!WizardMode) {
1650 ++nint;
1651 } else {
1652 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1653 }
1654 break;
1655 }
1656 }
1657 if (nsup + nint != 0) {
1658 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1659 }
1660 }
1661
1662 void DepChange::ContextStream::start() {
1663 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1664 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1665 _klass = new_type;
1666 _ti_base = NULL;
1667 _ti_index = 0;
1668 _ti_limit = 0;
1669 }
1670
1671 bool DepChange::ContextStream::next() {
1672 switch (_change_type) {
1673 case Start_Klass: // initial state; _klass is the new type
1674 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1675 _ti_index = 0;
1676 _change_type = Change_new_type;
1677 return true;
1678 case Change_new_type:
1679 // fall through:
1680 _change_type = Change_new_sub;
1681 case Change_new_sub:
1682 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1683 {
1684 _klass = InstanceKlass::cast(_klass)->super();
1685 if (_klass != NULL) {
1686 return true;
1687 }
1688 }
1689 // else set up _ti_limit and fall through:
1690 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1691 _change_type = Change_new_impl;
1692 case Change_new_impl:
1693 if (_ti_index < _ti_limit) {
1694 _klass = _ti_base->at(_ti_index++);
1695 return true;
1696 }
1697 // fall through:
1698 _change_type = NO_CHANGE; // iterator is exhausted
1699 case NO_CHANGE:
1700 break;
1701 default:
1702 ShouldNotReachHere();
1703 }
1704 return false;
1705 }
1706
1707 void KlassDepChange::initialize() {
1708 // entire transaction must be under this lock:
1709 assert_lock_strong(Compile_lock);
1710
1711 // Mark all dependee and all its superclasses
1712 // Mark transitive interfaces
1713 for (ContextStream str(*this); str.next(); ) {
1714 Klass* d = str.klass();
1715 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1716 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1717 }
1718 }
1719
1720 KlassDepChange::~KlassDepChange() {
1721 // Unmark all dependee and all its superclasses
1722 // Unmark transitive interfaces
1723 for (ContextStream str(*this); str.next(); ) {
1724 Klass* d = str.klass();
1725 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1726 }
1727 }
1728
1729 bool KlassDepChange::involves_context(Klass* k) {
1730 if (k == NULL || !k->oop_is_instance()) {
1731 return false;
1732 }
1733 InstanceKlass* ik = InstanceKlass::cast(k);
1734 bool is_contained = ik->is_marked_dependent();
1735 assert(is_contained == new_type()->is_subtype_of(k),
1736 "correct marking of potential context types");
1737 return is_contained;
1738 }
1739
1740 #ifndef PRODUCT
1741 void Dependencies::print_statistics() {
1742 if (deps_find_witness_print != 0) {
1743 // Call one final time, to flush out the data.
1744 deps_find_witness_print = -1;
1745 count_find_witness_calls();
1746 }
1747 }
1748 #endif