1 /*
2 * Copyright (c) 2005, 2025, 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 "ci/ciArrayKlass.hpp"
26 #include "ci/ciEnv.hpp"
27 #include "ci/ciKlass.hpp"
28 #include "ci/ciMethod.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/vmClasses.hpp"
31 #include "code/dependencies.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/compileLog.hpp"
34 #include "compiler/compileTask.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "oops/klass.hpp"
37 #include "oops/method.inline.hpp"
38 #include "oops/objArrayKlass.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/flags/flagSetting.hpp"
41 #include "runtime/handles.inline.hpp"
42 #include "runtime/javaThread.inline.hpp"
43 #include "runtime/jniHandles.inline.hpp"
44 #include "runtime/mutexLocker.hpp"
45 #include "runtime/perfData.hpp"
46 #include "runtime/vmThread.hpp"
47 #include "utilities/copy.hpp"
48
49
50 #ifdef ASSERT
51 static bool must_be_in_vm() {
52 Thread* thread = Thread::current();
53 if (thread->is_Java_thread()) {
54 return JavaThread::cast(thread)->thread_state() == _thread_in_vm;
55 } else {
56 return true; // Could be VMThread or GC thread
57 }
58 }
59 #endif //ASSERT
60
61 bool Dependencies::_verify_in_progress = false; // don't -Xlog:dependencies
62
63 void Dependencies::initialize(ciEnv* env) {
64 Arena* arena = env->arena();
65 _oop_recorder = env->oop_recorder();
66 _log = env->log();
67 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
68 #if INCLUDE_JVMCI
69 _using_dep_values = false;
70 #endif
71 DEBUG_ONLY(_deps[end_marker] = nullptr);
72 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
73 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, nullptr);
74 }
75 _content_bytes = nullptr;
76 _size_in_bytes = (size_t)-1;
77
78 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
79 }
80
81 void Dependencies::assert_evol_method(ciMethod* m) {
82 assert_common_1(evol_method, m);
83 }
84
85 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
86 if (ctxk->is_array_klass()) {
87 // As a special case, support this assertion on an array type,
88 // which reduces to an assertion on its element type.
89 // Note that this cannot be done with assertions that
90 // relate to concreteness or abstractness.
91 ciType* elemt = ctxk->as_array_klass()->base_element_type();
92 if (!elemt->is_instance_klass()) return; // Ex: int[][]
93 ctxk = elemt->as_instance_klass();
94 //if (ctxk->is_final()) return; // Ex: String[][]
95 }
96 check_ctxk(ctxk);
97 assert_common_1(leaf_type, ctxk);
98 }
99
100 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
101 check_ctxk_abstract(ctxk);
102 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
103 }
104
105 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
106 check_ctxk(ctxk);
107 check_unique_method(ctxk, uniqm);
108 assert_common_2(unique_concrete_method_2, ctxk, uniqm);
109 }
110
111 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm, ciKlass* resolved_klass, ciMethod* resolved_method) {
112 check_ctxk(ctxk);
113 check_unique_method(ctxk, uniqm);
114 assert_common_4(unique_concrete_method_4, ctxk, uniqm, resolved_klass, resolved_method);
115 }
116
117 void Dependencies::assert_unique_implementor(ciInstanceKlass* ctxk, ciInstanceKlass* uniqk) {
118 check_ctxk(ctxk);
119 check_unique_implementor(ctxk, uniqk);
120 assert_common_2(unique_implementor, ctxk, uniqk);
121 }
122
123 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
124 check_ctxk(ctxk);
125 assert_common_1(no_finalizable_subclasses, ctxk);
126 }
127
128 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
129 assert_common_2(call_site_target_value, call_site, method_handle);
130 }
131
132 #if INCLUDE_JVMCI
133
134 Dependencies::Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log) {
135 _oop_recorder = oop_recorder;
136 _log = log;
137 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
138 _using_dep_values = true;
139 DEBUG_ONLY(_dep_values[end_marker] = nullptr);
140 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
141 _dep_values[i] = new(arena) GrowableArray<DepValue>(arena, 10, 0, DepValue());
142 }
143 _content_bytes = nullptr;
144 _size_in_bytes = (size_t)-1;
145
146 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
147 }
148
149 void Dependencies::assert_evol_method(Method* m) {
150 assert_common_1(evol_method, DepValue(_oop_recorder, m));
151 }
152
153 void Dependencies::assert_has_no_finalizable_subclasses(Klass* ctxk) {
154 check_ctxk(ctxk);
155 assert_common_1(no_finalizable_subclasses, DepValue(_oop_recorder, ctxk));
156 }
157
158 void Dependencies::assert_leaf_type(Klass* ctxk) {
159 if (ctxk->is_array_klass()) {
160 // As a special case, support this assertion on an array type,
161 // which reduces to an assertion on its element type.
162 // Note that this cannot be done with assertions that
163 // relate to concreteness or abstractness.
164 BasicType elemt = ArrayKlass::cast(ctxk)->element_type();
165 if (is_java_primitive(elemt)) return; // Ex: int[][]
166 ctxk = ObjArrayKlass::cast(ctxk)->bottom_klass();
167 //if (ctxk->is_final()) return; // Ex: String[][]
168 }
169 check_ctxk(ctxk);
170 assert_common_1(leaf_type, DepValue(_oop_recorder, ctxk));
171 }
172
173 void Dependencies::assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck) {
174 check_ctxk_abstract(ctxk);
175 DepValue ctxk_dv(_oop_recorder, ctxk);
176 DepValue conck_dv(_oop_recorder, conck, &ctxk_dv);
177 assert_common_2(abstract_with_unique_concrete_subtype, ctxk_dv, conck_dv);
178 }
179
180 void Dependencies::assert_unique_implementor(InstanceKlass* ctxk, InstanceKlass* uniqk) {
181 check_ctxk(ctxk);
182 assert(ctxk->is_interface(), "not an interface");
183 assert(ctxk->implementor() == uniqk, "not a unique implementor");
184 assert_common_2(unique_implementor, DepValue(_oop_recorder, ctxk), DepValue(_oop_recorder, uniqk));
185 }
186
187 void Dependencies::assert_unique_concrete_method(Klass* ctxk, Method* uniqm) {
188 check_ctxk(ctxk);
189 check_unique_method(ctxk, uniqm);
190 assert_common_2(unique_concrete_method_2, DepValue(_oop_recorder, ctxk), DepValue(_oop_recorder, uniqm));
191 }
192
193 void Dependencies::assert_call_site_target_value(oop call_site, oop method_handle) {
194 assert_common_2(call_site_target_value, DepValue(_oop_recorder, JNIHandles::make_local(call_site)), DepValue(_oop_recorder, JNIHandles::make_local(method_handle)));
195 }
196
197 #endif // INCLUDE_JVMCI
198
199
200 // Helper function. If we are adding a new dep. under ctxk2,
201 // try to find an old dep. under a broader* ctxk1. If there is
202 //
203 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
204 int ctxk_i, ciKlass* ctxk2) {
205 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
206 if (ctxk2->is_subtype_of(ctxk1)) {
207 return true; // success, and no need to change
208 } else if (ctxk1->is_subtype_of(ctxk2)) {
209 // new context class fully subsumes previous one
210 deps->at_put(ctxk_i, ctxk2);
211 return true;
212 } else {
213 return false;
214 }
215 }
216
217 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
218 assert(dep_args(dept) == 1, "sanity");
219 log_dependency(dept, x);
220 GrowableArray<ciBaseObject*>* deps = _deps[dept];
221
222 // see if the same (or a similar) dep is already recorded
223 if (note_dep_seen(dept, x)) {
224 assert(deps->find(x) >= 0, "sanity");
225 } else {
226 deps->append(x);
227 }
228 }
229
230 void Dependencies::assert_common_2(DepType dept,
231 ciBaseObject* x0, ciBaseObject* x1) {
232 assert(dep_args(dept) == 2, "sanity");
233 log_dependency(dept, x0, x1);
234 GrowableArray<ciBaseObject*>* deps = _deps[dept];
235
236 // see if the same (or a similar) dep is already recorded
237 bool has_ctxk = has_explicit_context_arg(dept);
238 if (has_ctxk) {
239 assert(dep_context_arg(dept) == 0, "sanity");
240 if (note_dep_seen(dept, x1)) {
241 // look in this bucket for redundant assertions
242 const int stride = 2;
243 for (int i = deps->length(); (i -= stride) >= 0; ) {
244 ciBaseObject* y1 = deps->at(i+1);
245 if (x1 == y1) { // same subject; check the context
246 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
247 return;
248 }
249 }
250 }
251 }
252 } else {
253 bool dep_seen_x0 = note_dep_seen(dept, x0); // records x0 for future queries
254 bool dep_seen_x1 = note_dep_seen(dept, x1); // records x1 for future queries
255 if (dep_seen_x0 && dep_seen_x1) {
256 // look in this bucket for redundant assertions
257 const int stride = 2;
258 for (int i = deps->length(); (i -= stride) >= 0; ) {
259 ciBaseObject* y0 = deps->at(i+0);
260 ciBaseObject* y1 = deps->at(i+1);
261 if (x0 == y0 && x1 == y1) {
262 return;
263 }
264 }
265 }
266 }
267
268 // append the assertion in the correct bucket:
269 deps->append(x0);
270 deps->append(x1);
271 }
272
273 void Dependencies::assert_common_4(DepType dept,
274 ciKlass* ctxk, ciBaseObject* x1, ciBaseObject* x2, ciBaseObject* x3) {
275 assert(has_explicit_context_arg(dept), "sanity");
276 assert(dep_context_arg(dept) == 0, "sanity");
277 assert(dep_args(dept) == 4, "sanity");
278 log_dependency(dept, ctxk, x1, x2, x3);
279 GrowableArray<ciBaseObject*>* deps = _deps[dept];
280
281 // see if the same (or a similar) dep is already recorded
282 bool dep_seen_x1 = note_dep_seen(dept, x1); // records x1 for future queries
283 bool dep_seen_x2 = note_dep_seen(dept, x2); // records x2 for future queries
284 bool dep_seen_x3 = note_dep_seen(dept, x3); // records x3 for future queries
285 if (dep_seen_x1 && dep_seen_x2 && dep_seen_x3) {
286 // look in this bucket for redundant assertions
287 const int stride = 4;
288 for (int i = deps->length(); (i -= stride) >= 0; ) {
289 ciBaseObject* y1 = deps->at(i+1);
290 ciBaseObject* y2 = deps->at(i+2);
291 ciBaseObject* y3 = deps->at(i+3);
292 if (x1 == y1 && x2 == y2 && x3 == y3) { // same subjects; check the context
293 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
294 return;
295 }
296 }
297 }
298 }
299 // append the assertion in the correct bucket:
300 deps->append(ctxk);
301 deps->append(x1);
302 deps->append(x2);
303 deps->append(x3);
304 }
305
306 #if INCLUDE_JVMCI
307 bool Dependencies::maybe_merge_ctxk(GrowableArray<DepValue>* deps,
308 int ctxk_i, DepValue ctxk2_dv) {
309 Klass* ctxk1 = deps->at(ctxk_i).as_klass(_oop_recorder);
310 Klass* ctxk2 = ctxk2_dv.as_klass(_oop_recorder);
311 if (ctxk2->is_subtype_of(ctxk1)) {
312 return true; // success, and no need to change
313 } else if (ctxk1->is_subtype_of(ctxk2)) {
314 // new context class fully subsumes previous one
315 deps->at_put(ctxk_i, ctxk2_dv);
316 return true;
317 } else {
318 return false;
319 }
320 }
321
322 void Dependencies::assert_common_1(DepType dept, DepValue x) {
323 assert(dep_args(dept) == 1, "sanity");
324 //log_dependency(dept, x);
325 GrowableArray<DepValue>* deps = _dep_values[dept];
326
327 // see if the same (or a similar) dep is already recorded
328 if (note_dep_seen(dept, x)) {
329 assert(deps->find(x) >= 0, "sanity");
330 } else {
331 deps->append(x);
332 }
333 }
334
335 void Dependencies::assert_common_2(DepType dept,
336 DepValue x0, DepValue x1) {
337 assert(dep_args(dept) == 2, "sanity");
338 //log_dependency(dept, x0, x1);
339 GrowableArray<DepValue>* deps = _dep_values[dept];
340
341 // see if the same (or a similar) dep is already recorded
342 bool has_ctxk = has_explicit_context_arg(dept);
343 if (has_ctxk) {
344 assert(dep_context_arg(dept) == 0, "sanity");
345 if (note_dep_seen(dept, x1)) {
346 // look in this bucket for redundant assertions
347 const int stride = 2;
348 for (int i = deps->length(); (i -= stride) >= 0; ) {
349 DepValue y1 = deps->at(i+1);
350 if (x1 == y1) { // same subject; check the context
351 if (maybe_merge_ctxk(deps, i+0, x0)) {
352 return;
353 }
354 }
355 }
356 }
357 } else {
358 bool dep_seen_x0 = note_dep_seen(dept, x0); // records x0 for future queries
359 bool dep_seen_x1 = note_dep_seen(dept, x1); // records x1 for future queries
360 if (dep_seen_x0 && dep_seen_x1) {
361 // look in this bucket for redundant assertions
362 const int stride = 2;
363 for (int i = deps->length(); (i -= stride) >= 0; ) {
364 DepValue y0 = deps->at(i+0);
365 DepValue y1 = deps->at(i+1);
366 if (x0 == y0 && x1 == y1) {
367 return;
368 }
369 }
370 }
371 }
372
373 // append the assertion in the correct bucket:
374 deps->append(x0);
375 deps->append(x1);
376 }
377 #endif // INCLUDE_JVMCI
378
379 /// Support for encoding dependencies into an nmethod:
380
381 void Dependencies::copy_to(nmethod* nm) {
382 address beg = nm->dependencies_begin();
383 address end = nm->dependencies_end();
384 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
385 (void)memcpy(beg, content_bytes(), size_in_bytes());
386 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
387 }
388
389 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
390 for (int i = 0; i < narg; i++) {
391 int diff = p1[i]->ident() - p2[i]->ident();
392 if (diff != 0) return diff;
393 }
394 return 0;
395 }
396 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
397 { return sort_dep(p1, p2, 1); }
398 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
399 { return sort_dep(p1, p2, 2); }
400 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
401 { return sort_dep(p1, p2, 3); }
402 static int sort_dep_arg_4(ciBaseObject** p1, ciBaseObject** p2)
403 { return sort_dep(p1, p2, 4); }
404
405 #if INCLUDE_JVMCI
406 // metadata deps are sorted before object deps
407 static int sort_dep_value(Dependencies::DepValue* p1, Dependencies::DepValue* p2, int narg) {
408 for (int i = 0; i < narg; i++) {
409 int diff = p1[i].sort_key() - p2[i].sort_key();
410 if (diff != 0) return diff;
411 }
412 return 0;
413 }
414 static int sort_dep_value_arg_1(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
415 { return sort_dep_value(p1, p2, 1); }
416 static int sort_dep_value_arg_2(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
417 { return sort_dep_value(p1, p2, 2); }
418 static int sort_dep_value_arg_3(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
419 { return sort_dep_value(p1, p2, 3); }
420 #endif // INCLUDE_JVMCI
421
422 void Dependencies::sort_all_deps() {
423 #if INCLUDE_JVMCI
424 if (_using_dep_values) {
425 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
426 DepType dept = (DepType)deptv;
427 GrowableArray<DepValue>* deps = _dep_values[dept];
428 if (deps->length() <= 1) continue;
429 switch (dep_args(dept)) {
430 case 1: deps->sort(sort_dep_value_arg_1, 1); break;
431 case 2: deps->sort(sort_dep_value_arg_2, 2); break;
432 case 3: deps->sort(sort_dep_value_arg_3, 3); break;
433 default: ShouldNotReachHere(); break;
434 }
435 }
436 return;
437 }
438 #endif // INCLUDE_JVMCI
439 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
440 DepType dept = (DepType)deptv;
441 GrowableArray<ciBaseObject*>* deps = _deps[dept];
442 if (deps->length() <= 1) continue;
443 switch (dep_args(dept)) {
444 case 1: deps->sort(sort_dep_arg_1, 1); break;
445 case 2: deps->sort(sort_dep_arg_2, 2); break;
446 case 3: deps->sort(sort_dep_arg_3, 3); break;
447 case 4: deps->sort(sort_dep_arg_4, 4); break;
448 default: ShouldNotReachHere(); break;
449 }
450 }
451 }
452
453 size_t Dependencies::estimate_size_in_bytes() {
454 size_t est_size = 100;
455 #if INCLUDE_JVMCI
456 if (_using_dep_values) {
457 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
458 DepType dept = (DepType)deptv;
459 GrowableArray<DepValue>* deps = _dep_values[dept];
460 est_size += deps->length() * 2; // tags and argument(s)
461 }
462 return est_size;
463 }
464 #endif // INCLUDE_JVMCI
465 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
466 DepType dept = (DepType)deptv;
467 GrowableArray<ciBaseObject*>* deps = _deps[dept];
468 est_size += deps->length()*2; // tags and argument(s)
469 }
470 return est_size;
471 }
472
473 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
474 switch (dept) {
475 case unique_concrete_method_2:
476 case unique_concrete_method_4:
477 return x->as_metadata()->as_method()->holder();
478 default:
479 return nullptr; // let nullptr be nullptr
480 }
481 }
482
483 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
484 assert(must_be_in_vm(), "raw oops here");
485 switch (dept) {
486 case unique_concrete_method_2:
487 case unique_concrete_method_4:
488 assert(x->is_method(), "sanity");
489 return ((Method*)x)->method_holder();
490 default:
491 return nullptr; // let nullptr be nullptr
492 }
493 }
494
495 void Dependencies::encode_content_bytes() {
496 sort_all_deps();
497
498 // cast is safe, no deps can overflow INT_MAX
499 CompressedWriteStream bytes((int)estimate_size_in_bytes());
500
501 #if INCLUDE_JVMCI
502 if (_using_dep_values) {
503 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
504 DepType dept = (DepType)deptv;
505 GrowableArray<DepValue>* deps = _dep_values[dept];
506 if (deps->length() == 0) continue;
507 int stride = dep_args(dept);
508 int ctxkj = dep_context_arg(dept); // -1 if no context arg
509 assert(stride > 0, "sanity");
510 for (int i = 0; i < deps->length(); i += stride) {
511 jbyte code_byte = (jbyte)dept;
512 int skipj = -1;
513 if (ctxkj >= 0 && ctxkj+1 < stride) {
514 Klass* ctxk = deps->at(i+ctxkj+0).as_klass(_oop_recorder);
515 DepValue x = deps->at(i+ctxkj+1); // following argument
516 if (ctxk == ctxk_encoded_as_null(dept, x.as_metadata(_oop_recorder))) {
517 skipj = ctxkj; // we win: maybe one less oop to keep track of
518 code_byte |= default_context_type_bit;
519 }
520 }
521 bytes.write_byte(code_byte);
522 for (int j = 0; j < stride; j++) {
523 if (j == skipj) continue;
524 DepValue v = deps->at(i+j);
525 int idx = v.index();
526 bytes.write_int(idx);
527 }
528 }
529 }
530 } else {
531 #endif // INCLUDE_JVMCI
532 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
533 DepType dept = (DepType)deptv;
534 GrowableArray<ciBaseObject*>* deps = _deps[dept];
535 if (deps->length() == 0) continue;
536 int stride = dep_args(dept);
537 int ctxkj = dep_context_arg(dept); // -1 if no context arg
538 assert(stride > 0, "sanity");
539 for (int i = 0; i < deps->length(); i += stride) {
540 jbyte code_byte = (jbyte)dept;
541 int skipj = -1;
542 if (ctxkj >= 0 && ctxkj+1 < stride) {
543 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
544 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
545 if (ctxk == ctxk_encoded_as_null(dept, x)) {
546 skipj = ctxkj; // we win: maybe one less oop to keep track of
547 code_byte |= default_context_type_bit;
548 }
549 }
550 bytes.write_byte(code_byte);
551 for (int j = 0; j < stride; j++) {
552 if (j == skipj) continue;
553 ciBaseObject* v = deps->at(i+j);
554 int idx;
555 if (v->is_object()) {
556 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
557 } else {
558 ciMetadata* meta = v->as_metadata();
559 idx = _oop_recorder->find_index(meta->constant_encoding());
560 }
561 bytes.write_int(idx);
562 }
563 }
564 }
565 #if INCLUDE_JVMCI
566 }
567 #endif
568
569 // write a sentinel byte to mark the end
570 bytes.write_byte(end_marker);
571
572 // round it out to a word boundary
573 while (bytes.position() % sizeof(HeapWord) != 0) {
574 bytes.write_byte(end_marker);
575 }
576
577 // check whether the dept byte encoding really works
578 assert((jbyte)default_context_type_bit != 0, "byte overflow");
579
580 _content_bytes = bytes.buffer();
581 _size_in_bytes = bytes.position();
582 }
583
584
585 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
586 "end_marker",
587 "evol_method",
588 "leaf_type",
589 "abstract_with_unique_concrete_subtype",
590 "unique_concrete_method_2",
591 "unique_concrete_method_4",
592 "unique_implementor",
593 "no_finalizable_subclasses",
594 "call_site_target_value"
595 };
596
597 int Dependencies::_dep_args[TYPE_LIMIT] = {
598 -1,// end_marker
599 1, // evol_method m
600 1, // leaf_type ctxk
601 2, // abstract_with_unique_concrete_subtype ctxk, k
602 2, // unique_concrete_method_2 ctxk, m
603 4, // unique_concrete_method_4 ctxk, m, resolved_klass, resolved_method
604 2, // unique_implementor ctxk, implementor
605 1, // no_finalizable_subclasses ctxk
606 2 // call_site_target_value call_site, method_handle
607 };
608
609 const char* Dependencies::dep_name(Dependencies::DepType dept) {
610 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
611 return _dep_name[dept];
612 }
613
614 int Dependencies::dep_args(Dependencies::DepType dept) {
615 if (!dept_in_mask(dept, all_types)) return -1;
616 return _dep_args[dept];
617 }
618
619 void Dependencies::check_valid_dependency_type(DepType dept) {
620 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, "invalid dependency type: %d", (int) dept);
621 }
622
623 Dependencies::DepType Dependencies::validate_dependencies(CompileTask* task, char** failure_detail) {
624 int klass_violations = 0;
625 DepType result = end_marker;
626 for (Dependencies::DepStream deps(this); deps.next(); ) {
627 Klass* witness = deps.check_dependency();
628 if (witness != nullptr) {
629 if (klass_violations == 0) {
630 result = deps.type();
631 if (failure_detail != nullptr && klass_violations == 0) {
632 // Use a fixed size buffer to prevent the string stream from
633 // resizing in the context of an inner resource mark.
634 char* buffer = NEW_RESOURCE_ARRAY(char, O_BUFLEN);
635 stringStream st(buffer, O_BUFLEN);
636 deps.print_dependency(&st, witness, true);
637 *failure_detail = st.as_string();
638 }
639 }
640 klass_violations++;
641 if (xtty == nullptr) {
642 // If we're not logging then a single violation is sufficient,
643 // otherwise we want to log all the dependences which were
644 // violated.
645 break;
646 }
647 }
648 }
649
650 return result;
651 }
652
653 // for the sake of the compiler log, print out current dependencies:
654 void Dependencies::log_all_dependencies() {
655 if (log() == nullptr) return;
656 ResourceMark rm;
657 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
658 DepType dept = (DepType)deptv;
659 GrowableArray<ciBaseObject*>* deps = _deps[dept];
660 int deplen = deps->length();
661 if (deplen == 0) {
662 continue;
663 }
664 int stride = dep_args(dept);
665 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
666 for (int i = 0; i < deps->length(); i += stride) {
667 for (int j = 0; j < stride; j++) {
668 // flush out the identities before printing
669 ciargs->push(deps->at(i+j));
670 }
671 write_dependency_to(log(), dept, ciargs);
672 ciargs->clear();
673 }
674 guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
675 }
676 }
677
678 void Dependencies::write_dependency_to(CompileLog* log,
679 DepType dept,
680 GrowableArray<DepArgument>* args,
681 Klass* witness) {
682 if (log == nullptr) {
683 return;
684 }
685 ResourceMark rm;
686 ciEnv* env = ciEnv::current();
687 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
688 for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
689 DepArgument arg = *it;
690 if (arg.is_oop()) {
691 ciargs->push(env->get_object(arg.oop_value()));
692 } else {
693 ciargs->push(env->get_metadata(arg.metadata_value()));
694 }
695 }
696 int argslen = ciargs->length();
697 Dependencies::write_dependency_to(log, dept, ciargs, witness);
698 guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
699 }
700
701 void Dependencies::write_dependency_to(CompileLog* log,
702 DepType dept,
703 GrowableArray<ciBaseObject*>* args,
704 Klass* witness) {
705 if (log == nullptr) {
706 return;
707 }
708 ResourceMark rm;
709 GrowableArray<int>* argids = new GrowableArray<int>(args->length());
710 for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
711 ciBaseObject* obj = *it;
712 if (obj->is_object()) {
713 argids->push(log->identify(obj->as_object()));
714 } else {
715 argids->push(log->identify(obj->as_metadata()));
716 }
717 }
718 if (witness != nullptr) {
719 log->begin_elem("dependency_failed");
720 } else {
721 log->begin_elem("dependency");
722 }
723 log->print(" type='%s'", dep_name(dept));
724 const int ctxkj = dep_context_arg(dept); // -1 if no context arg
725 if (ctxkj >= 0 && ctxkj < argids->length()) {
726 log->print(" ctxk='%d'", argids->at(ctxkj));
727 }
728 // write remaining arguments, if any.
729 for (int j = 0; j < argids->length(); j++) {
730 if (j == ctxkj) continue; // already logged
731 if (j == 1) {
732 log->print( " x='%d'", argids->at(j));
733 } else {
734 log->print(" x%d='%d'", j, argids->at(j));
735 }
736 }
737 if (witness != nullptr) {
738 log->object("witness", witness);
739 log->stamp();
740 }
741 log->end_elem();
742 }
743
744 void Dependencies::write_dependency_to(xmlStream* xtty,
745 DepType dept,
746 GrowableArray<DepArgument>* args,
747 Klass* witness) {
748 if (xtty == nullptr) {
749 return;
750 }
751 Thread* thread = Thread::current();
752 HandleMark rm(thread);
753 ttyLocker ttyl;
754 int ctxkj = dep_context_arg(dept); // -1 if no context arg
755 if (witness != nullptr) {
756 xtty->begin_elem("dependency_failed");
757 } else {
758 xtty->begin_elem("dependency");
759 }
760 xtty->print(" type='%s'", dep_name(dept));
761 if (ctxkj >= 0) {
762 xtty->object("ctxk", args->at(ctxkj).metadata_value());
763 }
764 // write remaining arguments, if any.
765 for (int j = 0; j < args->length(); j++) {
766 if (j == ctxkj) continue; // already logged
767 DepArgument arg = args->at(j);
768 if (j == 1) {
769 if (arg.is_oop()) {
770 xtty->object("x", Handle(thread, arg.oop_value()));
771 } else {
772 xtty->object("x", arg.metadata_value());
773 }
774 } else {
775 char xn[12];
776 os::snprintf_checked(xn, sizeof(xn), "x%d", j);
777 if (arg.is_oop()) {
778 xtty->object(xn, Handle(thread, arg.oop_value()));
779 } else {
780 xtty->object(xn, arg.metadata_value());
781 }
782 }
783 }
784 if (witness != nullptr) {
785 xtty->object("witness", witness);
786 xtty->stamp();
787 }
788 xtty->end_elem();
789 }
790
791 void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
792 Klass* witness, outputStream* st) {
793 ResourceMark rm;
794 ttyLocker ttyl; // keep the following output all in one block
795 st->print_cr("%s of type %s",
796 (witness == nullptr)? "Dependency": "Failed dependency",
797 dep_name(dept));
798 // print arguments
799 int ctxkj = dep_context_arg(dept); // -1 if no context arg
800 for (int j = 0; j < args->length(); j++) {
801 DepArgument arg = args->at(j);
802 bool put_star = false;
803 if (arg.is_null()) continue;
804 const char* what;
805 if (j == ctxkj) {
806 assert(arg.is_metadata(), "must be");
807 what = "context";
808 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
809 } else if (arg.is_method()) {
810 what = "method ";
811 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value(), nullptr);
812 } else if (arg.is_klass()) {
813 what = "class ";
814 } else {
815 what = "object ";
816 }
817 st->print(" %s = %s", what, (put_star? "*": ""));
818 if (arg.is_klass()) {
819 st->print("%s", ((Klass*)arg.metadata_value())->external_name());
820 } else if (arg.is_method()) {
821 ((Method*)arg.metadata_value())->print_value_on(st);
822 } else if (arg.is_oop()) {
823 arg.oop_value()->print_value_on(st);
824 } else {
825 ShouldNotReachHere(); // Provide impl for this type.
826 }
827
828 st->cr();
829 }
830 if (witness != nullptr) {
831 bool put_star = !Dependencies::is_concrete_klass(witness);
832 st->print(" witness = %s%s",
833 (put_star ? "*": ""),
834 witness->external_name());
835 if (witness->is_instance_klass()) {
836 st->print(" (%s)", InstanceKlass::cast(witness)->init_state_name());
837 }
838 st->cr();
839 }
840 }
841
842 void Dependencies::DepStream::log_dependency(Klass* witness) {
843 if (_deps == nullptr && xtty == nullptr) return; // fast cutout for runtime
844 ResourceMark rm;
845 const int nargs = argument_count();
846 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
847 for (int j = 0; j < nargs; j++) {
848 if (is_oop_argument(j)) {
849 args->push(argument_oop(j));
850 } else {
851 args->push(argument(j));
852 }
853 }
854 int argslen = args->length();
855 if (_deps != nullptr && _deps->log() != nullptr) {
856 if (ciEnv::current() != nullptr) {
857 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
858 } else {
859 // Treat the CompileLog as an xmlstream instead
860 Dependencies::write_dependency_to((xmlStream*)_deps->log(), type(), args, witness);
861 }
862 } else {
863 Dependencies::write_dependency_to(xtty, type(), args, witness);
864 }
865 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
866 }
867
868 void Dependencies::DepStream::print_dependency(outputStream* st, Klass* witness, bool verbose) {
869 ResourceMark rm;
870 int nargs = argument_count();
871 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
872 for (int j = 0; j < nargs; j++) {
873 if (is_oop_argument(j)) {
874 args->push(argument_oop(j));
875 } else {
876 args->push(argument(j));
877 }
878 }
879 int argslen = args->length();
880 Dependencies::print_dependency(type(), args, witness, st);
881 if (verbose) {
882 if (_code != nullptr) {
883 st->print(" code: ");
884 _code->print_value_on(st);
885 st->cr();
886 }
887 }
888 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
889 }
890
891
892 /// Dependency stream support (decodes dependencies from an nmethod):
893
894 #ifdef ASSERT
895 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
896 assert(must_be_in_vm(), "raw oops here");
897 _byte_limit = byte_limit;
898 _type = undefined_dependency; // defeat "already at end" assert
899 assert((_code!=nullptr) + (_deps!=nullptr) == 1, "one or t'other");
900 }
901 #endif //ASSERT
902
903 bool Dependencies::DepStream::next() {
904 assert(_type != end_marker, "already at end");
905 if (_bytes.position() == 0 && _code != nullptr
906 && _code->dependencies_size() == 0) {
907 // Method has no dependencies at all.
908 return false;
909 }
910 int code_byte = (_bytes.read_byte() & 0xFF);
911 if (code_byte == end_marker) {
912 DEBUG_ONLY(_type = end_marker);
913 return false;
914 } else {
915 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
916 code_byte -= ctxk_bit;
917 DepType dept = (DepType)code_byte;
918 _type = dept;
919 Dependencies::check_valid_dependency_type(dept);
920 int stride = _dep_args[dept];
921 assert(stride == dep_args(dept), "sanity");
922 int skipj = -1;
923 if (ctxk_bit != 0) {
924 skipj = 0; // currently the only context argument is at zero
925 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
926 }
927 for (int j = 0; j < stride; j++) {
928 _xi[j] = (j == skipj)? 0: _bytes.read_int();
929 }
930 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
931 return true;
932 }
933 }
934
935 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
936 Metadata* o = nullptr;
937 if (_code != nullptr) {
938 o = _code->metadata_at(i);
939 } else {
940 o = _deps->oop_recorder()->metadata_at(i);
941 }
942 return o;
943 }
944
945 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
946 return (_code != nullptr)
947 ? _code->oop_at(i)
948 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
949 }
950
951 Metadata* Dependencies::DepStream::argument(int i) {
952 Metadata* result = recorded_metadata_at(argument_index(i));
953
954 if (result == nullptr) { // Explicit context argument can be compressed
955 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
956 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
957 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
958 }
959 }
960
961 assert(result == nullptr || result->is_klass() || result->is_method(), "must be");
962 return result;
963 }
964
965 /**
966 * Returns a unique identifier for each dependency argument.
967 */
968 uintptr_t Dependencies::DepStream::get_identifier(int i) {
969 if (is_oop_argument(i)) {
970 return (uintptr_t)(oopDesc*)argument_oop(i);
971 } else {
972 return (uintptr_t)argument(i);
973 }
974 }
975
976 oop Dependencies::DepStream::argument_oop(int i) {
977 oop result = recorded_oop_at(argument_index(i));
978 assert(oopDesc::is_oop_or_null(result), "must be");
979 return result;
980 }
981
982 InstanceKlass* Dependencies::DepStream::context_type() {
983 assert(must_be_in_vm(), "raw oops here");
984
985 // Most dependencies have an explicit context type argument.
986 {
987 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
988 if (ctxkj >= 0) {
989 Metadata* k = argument(ctxkj);
990 assert(k != nullptr && k->is_klass(), "type check");
991 return InstanceKlass::cast((Klass*)k);
992 }
993 }
994
995 // Some dependencies are using the klass of the first object
996 // argument as implicit context type.
997 {
998 int ctxkj = dep_implicit_context_arg(type());
999 if (ctxkj >= 0) {
1000 Klass* k = argument_oop(ctxkj)->klass();
1001 assert(k != nullptr, "type check");
1002 return InstanceKlass::cast(k);
1003 }
1004 }
1005
1006 // And some dependencies don't have a context type at all,
1007 // e.g. evol_method.
1008 return nullptr;
1009 }
1010
1011 // ----------------- DependencySignature --------------------------------------
1012 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
1013 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
1014 return false;
1015 }
1016
1017 for (int i = 0; i < s1.args_count(); i++) {
1018 if (s1.arg(i) != s2.arg(i)) {
1019 return false;
1020 }
1021 }
1022 return true;
1023 }
1024
1025 /// Checking dependencies
1026
1027 // This hierarchy walker inspects subtypes of a given type, trying to find a "bad" class which breaks a dependency.
1028 // Such a class is called a "witness" to the broken dependency.
1029 // While searching around, we ignore "participants", which are already known to the dependency.
1030 class AbstractClassHierarchyWalker {
1031 public:
1032 enum { PARTICIPANT_LIMIT = 3 };
1033
1034 private:
1035 // if non-zero, tells how many witnesses to convert to participants
1036 uint _record_witnesses;
1037
1038 // special classes which are not allowed to be witnesses:
1039 Klass* _participants[PARTICIPANT_LIMIT+1];
1040 uint _num_participants;
1041
1042 #ifdef ASSERT
1043 uint _nof_requests; // one-shot walker
1044 #endif // ASSERT
1045
1046 static PerfCounter* _perf_find_witness_anywhere_calls_count;
1047 static PerfCounter* _perf_find_witness_anywhere_steps_count;
1048 static PerfCounter* _perf_find_witness_in_calls_count;
1049
1050 protected:
1051 virtual Klass* find_witness_in(KlassDepChange& changes) = 0;
1052 virtual Klass* find_witness_anywhere(InstanceKlass* context_type) = 0;
1053
1054 AbstractClassHierarchyWalker(Klass* participant) : _record_witnesses(0), _num_participants(0)
1055 #ifdef ASSERT
1056 , _nof_requests(0)
1057 #endif // ASSERT
1058 {
1059 for (uint i = 0; i < PARTICIPANT_LIMIT+1; i++) {
1060 _participants[i] = nullptr;
1061 }
1062 if (participant != nullptr) {
1063 add_participant(participant);
1064 }
1065 }
1066
1067 bool is_participant(Klass* k) {
1068 for (uint i = 0; i < _num_participants; i++) {
1069 if (_participants[i] == k) {
1070 return true;
1071 }
1072 }
1073 return false;
1074 }
1075
1076 bool record_witness(Klass* witness) {
1077 if (_record_witnesses > 0) {
1078 --_record_witnesses;
1079 add_participant(witness);
1080 return false; // not a witness
1081 } else {
1082 return true; // is a witness
1083 }
1084 }
1085
1086 class CountingClassHierarchyIterator : public ClassHierarchyIterator {
1087 private:
1088 jlong _nof_steps;
1089 public:
1090 CountingClassHierarchyIterator(InstanceKlass* root) : ClassHierarchyIterator(root), _nof_steps(0) {}
1091
1092 void next() {
1093 _nof_steps++;
1094 ClassHierarchyIterator::next();
1095 }
1096
1097 ~CountingClassHierarchyIterator() {
1098 if (UsePerfData) {
1099 _perf_find_witness_anywhere_steps_count->inc(_nof_steps);
1100 }
1101 }
1102 };
1103
1104 public:
1105 uint num_participants() { return _num_participants; }
1106 Klass* participant(uint n) {
1107 assert(n <= _num_participants, "oob");
1108 if (n < _num_participants) {
1109 return _participants[n];
1110 } else {
1111 return nullptr;
1112 }
1113 }
1114
1115 void add_participant(Klass* participant) {
1116 assert(!is_participant(participant), "sanity");
1117 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
1118 uint np = _num_participants++;
1119 _participants[np] = participant;
1120 }
1121
1122 void record_witnesses(uint add) {
1123 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
1124 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
1125 _record_witnesses = add;
1126 }
1127
1128 Klass* find_witness(InstanceKlass* context_type, KlassDepChange* changes = nullptr);
1129
1130 static void init();
1131 static void print_statistics();
1132 };
1133
1134 PerfCounter* AbstractClassHierarchyWalker::_perf_find_witness_anywhere_calls_count = nullptr;
1135 PerfCounter* AbstractClassHierarchyWalker::_perf_find_witness_anywhere_steps_count = nullptr;
1136 PerfCounter* AbstractClassHierarchyWalker::_perf_find_witness_in_calls_count = nullptr;
1137
1138 void AbstractClassHierarchyWalker::init() {
1139 if (UsePerfData) {
1140 EXCEPTION_MARK;
1141 _perf_find_witness_anywhere_calls_count =
1142 PerfDataManager::create_counter(SUN_CI, "findWitnessAnywhere", PerfData::U_Events, CHECK);
1143 _perf_find_witness_anywhere_steps_count =
1144 PerfDataManager::create_counter(SUN_CI, "findWitnessAnywhereSteps", PerfData::U_Events, CHECK);
1145 _perf_find_witness_in_calls_count =
1146 PerfDataManager::create_counter(SUN_CI, "findWitnessIn", PerfData::U_Events, CHECK);
1147 }
1148 }
1149
1150 Klass* AbstractClassHierarchyWalker::find_witness(InstanceKlass* context_type, KlassDepChange* changes) {
1151 // Current thread must be in VM (not native mode, as in CI):
1152 assert(must_be_in_vm(), "raw oops here");
1153 // Must not move the class hierarchy during this check:
1154 assert_locked_or_safepoint(Compile_lock);
1155 assert(_nof_requests++ == 0, "repeated requests are not supported");
1156
1157 assert(changes == nullptr || changes->involves_context(context_type), "irrelevant dependency");
1158
1159 // (Note: Interfaces do not have subclasses.)
1160 // If it is an interface, search its direct implementors.
1161 // (Their subclasses are additional indirect implementors. See InstanceKlass::add_implementor().)
1162 if (context_type->is_interface()) {
1163 int nof_impls = context_type->nof_implementors();
1164 if (nof_impls == 0) {
1165 return nullptr; // no implementors
1166 } else if (nof_impls == 1) { // unique implementor
1167 assert(context_type != context_type->implementor(), "not unique");
1168 context_type = context_type->implementor();
1169 } else { // nof_impls >= 2
1170 // Avoid this case: *I.m > { A.m, C }; B.m > C
1171 // Here, I.m has 2 concrete implementations, but m appears unique
1172 // as A.m, because the search misses B.m when checking C.
1173 // The inherited method B.m was getting missed by the walker
1174 // when interface 'I' was the starting point.
1175 // %%% Until this is fixed more systematically, bail out.
1176 return context_type;
1177 }
1178 }
1179 assert(!context_type->is_interface(), "no interfaces allowed");
1180
1181 if (changes != nullptr) {
1182 if (UsePerfData) {
1183 _perf_find_witness_in_calls_count->inc();
1184 }
1185 return find_witness_in(*changes);
1186 } else {
1187 if (UsePerfData) {
1188 _perf_find_witness_anywhere_calls_count->inc();
1189 }
1190 return find_witness_anywhere(context_type);
1191 }
1192 }
1193
1194 class ConcreteSubtypeFinder : public AbstractClassHierarchyWalker {
1195 private:
1196 bool is_witness(Klass* k);
1197
1198 protected:
1199 virtual Klass* find_witness_in(KlassDepChange& changes);
1200 virtual Klass* find_witness_anywhere(InstanceKlass* context_type);
1201
1202 public:
1203 ConcreteSubtypeFinder(Klass* participant = nullptr) : AbstractClassHierarchyWalker(participant) {}
1204 };
1205
1206 bool ConcreteSubtypeFinder::is_witness(Klass* k) {
1207 if (Dependencies::is_concrete_klass(k)) {
1208 return record_witness(k); // concrete subtype
1209 } else {
1210 return false; // not a concrete class
1211 }
1212 }
1213
1214 Klass* ConcreteSubtypeFinder::find_witness_in(KlassDepChange& changes) {
1215 // When looking for unexpected concrete types, do not look beneath expected ones:
1216 // * CX > CC > C' is OK, even if C' is new.
1217 // * CX > { CC, C' } is not OK if C' is new, and C' is the witness.
1218 Klass* new_type = changes.as_new_klass_change()->new_type();
1219 assert(!is_participant(new_type), "only old classes are participants");
1220 // If the new type is a subtype of a participant, we are done.
1221 for (uint i = 0; i < num_participants(); i++) {
1222 if (changes.involves_context(participant(i))) {
1223 // new guy is protected from this check by previous participant
1224 return nullptr;
1225 }
1226 }
1227 if (is_witness(new_type)) {
1228 return new_type;
1229 }
1230 // No witness found. The dependency remains unbroken.
1231 return nullptr;
1232 }
1233
1234 Klass* ConcreteSubtypeFinder::find_witness_anywhere(InstanceKlass* context_type) {
1235 for (CountingClassHierarchyIterator iter(context_type); !iter.done(); iter.next()) {
1236 Klass* sub = iter.klass();
1237 // Do not report participant types.
1238 if (is_participant(sub)) {
1239 // Don't walk beneath a participant since it hides witnesses.
1240 iter.skip_subclasses();
1241 } else if (is_witness(sub)) {
1242 return sub; // found a witness
1243 }
1244 }
1245 // No witness found. The dependency remains unbroken.
1246 return nullptr;
1247 }
1248
1249 class ConcreteMethodFinder : public AbstractClassHierarchyWalker {
1250 private:
1251 Symbol* _name;
1252 Symbol* _signature;
1253
1254 // cache of method lookups
1255 Method* _found_methods[PARTICIPANT_LIMIT+1];
1256
1257 bool is_witness(Klass* k);
1258
1259 protected:
1260 virtual Klass* find_witness_in(KlassDepChange& changes);
1261 virtual Klass* find_witness_anywhere(InstanceKlass* context_type);
1262
1263 public:
1264 bool witnessed_reabstraction_in_supers(Klass* k);
1265
1266 ConcreteMethodFinder(Method* m, Klass* participant = nullptr) : AbstractClassHierarchyWalker(participant) {
1267 assert(m != nullptr && m->is_method(), "sanity");
1268 _name = m->name();
1269 _signature = m->signature();
1270
1271 for (int i = 0; i < PARTICIPANT_LIMIT+1; i++) {
1272 _found_methods[i] = nullptr;
1273 }
1274 }
1275
1276 // Note: If n==num_participants, returns nullptr.
1277 Method* found_method(uint n) {
1278 assert(n <= num_participants(), "oob");
1279 Method* fm = _found_methods[n];
1280 assert(n == num_participants() || fm != nullptr, "proper usage");
1281 if (fm != nullptr && fm->method_holder() != participant(n)) {
1282 // Default methods from interfaces can be added to classes. In
1283 // that case the holder of the method is not the class but the
1284 // interface where it's defined.
1285 assert(fm->is_default_method(), "sanity");
1286 return nullptr;
1287 }
1288 return fm;
1289 }
1290
1291 void add_participant(Klass* participant) {
1292 AbstractClassHierarchyWalker::add_participant(participant);
1293 _found_methods[num_participants()] = nullptr;
1294 }
1295
1296 bool record_witness(Klass* witness, Method* m) {
1297 _found_methods[num_participants()] = m;
1298 return AbstractClassHierarchyWalker::record_witness(witness);
1299 }
1300
1301 private:
1302 static PerfCounter* _perf_find_witness_anywhere_calls_count;
1303 static PerfCounter* _perf_find_witness_anywhere_steps_count;
1304 static PerfCounter* _perf_find_witness_in_calls_count;
1305
1306 public:
1307 static void init();
1308 static void print_statistics();
1309 };
1310
1311 bool ConcreteMethodFinder::is_witness(Klass* k) {
1312 if (is_participant(k)) {
1313 return false; // do not report participant types
1314 }
1315 if (k->is_instance_klass()) {
1316 InstanceKlass* ik = InstanceKlass::cast(k);
1317 // Search class hierarchy first, skipping private implementations
1318 // as they never override any inherited methods
1319 Method* m = ik->find_instance_method(_name, _signature, Klass::PrivateLookupMode::skip);
1320 if (Dependencies::is_concrete_method(m, ik)) {
1321 return record_witness(k, m); // concrete method found
1322 } else {
1323 // Check for re-abstraction of method
1324 if (!ik->is_interface() && m != nullptr && m->is_abstract()) {
1325 // Found a matching abstract method 'm' in the class hierarchy.
1326 // This is fine iff 'k' is an abstract class and all concrete subtypes
1327 // of 'k' override 'm' and are participates of the current search.
1328 ConcreteSubtypeFinder wf;
1329 for (uint i = 0; i < num_participants(); i++) {
1330 Klass* p = participant(i);
1331 wf.add_participant(p);
1332 }
1333 Klass* w = wf.find_witness(ik);
1334 if (w != nullptr) {
1335 Method* wm = InstanceKlass::cast(w)->find_instance_method(_name, _signature, Klass::PrivateLookupMode::skip);
1336 if (!Dependencies::is_concrete_method(wm, w)) {
1337 // Found a concrete subtype 'w' which does not override abstract method 'm'.
1338 // Bail out because 'm' could be called with 'w' as receiver (leading to an
1339 // AbstractMethodError) and thus the method we are looking for is not unique.
1340 return record_witness(k, m);
1341 }
1342 }
1343 }
1344 // Check interface defaults also, if any exist.
1345 Array<Method*>* default_methods = ik->default_methods();
1346 if (default_methods != nullptr) {
1347 Method* dm = ik->find_method(default_methods, _name, _signature);
1348 if (Dependencies::is_concrete_method(dm, nullptr)) {
1349 return record_witness(k, dm); // default method found
1350 }
1351 }
1352 return false; // no concrete method found
1353 }
1354 } else {
1355 return false; // no methods to find in an array type
1356 }
1357 }
1358
1359 Klass* ConcreteMethodFinder::find_witness_in(KlassDepChange& changes) {
1360 // When looking for unexpected concrete methods, look beneath expected ones, to see if there are overrides.
1361 // * CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
1362 Klass* new_type = changes.as_new_klass_change()->new_type();
1363 assert(!is_participant(new_type), "only old classes are participants");
1364 if (is_witness(new_type)) {
1365 return new_type;
1366 } else {
1367 // No witness found, but is_witness() doesn't detect method re-abstraction in case of spot-checking.
1368 if (witnessed_reabstraction_in_supers(new_type)) {
1369 return new_type;
1370 }
1371 }
1372 // No witness found. The dependency remains unbroken.
1373 return nullptr;
1374 }
1375
1376 bool ConcreteMethodFinder::witnessed_reabstraction_in_supers(Klass* k) {
1377 if (!k->is_instance_klass()) {
1378 return false; // no methods to find in an array type
1379 } else {
1380 // Looking for a case when an abstract method is inherited into a concrete class.
1381 if (Dependencies::is_concrete_klass(k) && !k->is_interface()) {
1382 Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature, Klass::PrivateLookupMode::skip);
1383 if (m != nullptr) {
1384 return false; // no reabstraction possible: local method found
1385 }
1386 for (InstanceKlass* super = k->java_super(); super != nullptr; super = super->java_super()) {
1387 m = super->find_instance_method(_name, _signature, Klass::PrivateLookupMode::skip);
1388 if (m != nullptr) { // inherited method found
1389 if (m->is_abstract() || m->is_overpass()) {
1390 return record_witness(super, m); // abstract method found
1391 }
1392 return false;
1393 }
1394 }
1395 // Miranda.
1396 return true;
1397 }
1398 return false;
1399 }
1400 }
1401
1402
1403 Klass* ConcreteMethodFinder::find_witness_anywhere(InstanceKlass* context_type) {
1404 // Walk hierarchy under a context type, looking for unexpected types.
1405 for (CountingClassHierarchyIterator iter(context_type); !iter.done(); iter.next()) {
1406 Klass* sub = iter.klass();
1407 if (is_witness(sub)) {
1408 return sub; // found a witness
1409 }
1410 }
1411 // No witness found. The dependency remains unbroken.
1412 return nullptr;
1413 }
1414
1415 // For some method m and some class ctxk (subclass of method holder),
1416 // enumerate all distinct overrides of m in concrete subclasses of ctxk.
1417 // It relies on vtable/itable information to perform method selection on each linked subclass
1418 // and ignores all non yet linked ones (speculatively treat them as "effectively abstract").
1419 class LinkedConcreteMethodFinder : public AbstractClassHierarchyWalker {
1420 private:
1421 InstanceKlass* _resolved_klass; // resolved class (JVMS-5.4.3.1)
1422 InstanceKlass* _declaring_klass; // the holder of resolved method (JVMS-5.4.3.3)
1423 int _vtable_index; // vtable/itable index of the resolved method
1424 bool _do_itable_lookup; // choose between itable and vtable lookup logic
1425
1426 // cache of method lookups
1427 Method* _found_methods[PARTICIPANT_LIMIT+1];
1428
1429 bool is_witness(Klass* k);
1430 Method* select_method(InstanceKlass* recv_klass);
1431 static int compute_vtable_index(InstanceKlass* resolved_klass, Method* resolved_method, bool& is_itable_index);
1432 static bool is_concrete_klass(InstanceKlass* ik);
1433
1434 void add_participant(Method* m, Klass* participant) {
1435 uint np = num_participants();
1436 AbstractClassHierarchyWalker::add_participant(participant);
1437 assert(np + 1 == num_participants(), "sanity");
1438 _found_methods[np] = m; // record the method for the participant
1439 }
1440
1441 bool record_witness(Klass* witness, Method* m) {
1442 for (uint i = 0; i < num_participants(); i++) {
1443 if (found_method(i) == m) {
1444 return false; // already recorded
1445 }
1446 }
1447 // Record not yet seen method.
1448 _found_methods[num_participants()] = m;
1449 return AbstractClassHierarchyWalker::record_witness(witness);
1450 }
1451
1452 void initialize(Method* participant) {
1453 for (uint i = 0; i < PARTICIPANT_LIMIT+1; i++) {
1454 _found_methods[i] = nullptr;
1455 }
1456 if (participant != nullptr) {
1457 add_participant(participant, participant->method_holder());
1458 }
1459 }
1460
1461 protected:
1462 virtual Klass* find_witness_in(KlassDepChange& changes);
1463 virtual Klass* find_witness_anywhere(InstanceKlass* context_type);
1464
1465 public:
1466 // In order to perform method selection, the following info is needed:
1467 // (1) interface or virtual call;
1468 // (2) vtable/itable index;
1469 // (3) declaring class (in case of interface call).
1470 //
1471 // It is prepared based on the results of method resolution: resolved class and resolved method (as specified in JVMS-5.4.3.3).
1472 // Optionally, a method which was previously determined as a unique target (uniqm) is added as a participant
1473 // to enable dependency spot-checking and speed up the search.
1474 LinkedConcreteMethodFinder(InstanceKlass* resolved_klass, Method* resolved_method, Method* uniqm = nullptr) : AbstractClassHierarchyWalker(nullptr) {
1475 assert(resolved_klass->is_linked(), "required");
1476 assert(resolved_method->method_holder()->is_linked(), "required");
1477 assert(!resolved_method->can_be_statically_bound(), "no vtable index available");
1478
1479 _resolved_klass = resolved_klass;
1480 _declaring_klass = resolved_method->method_holder();
1481 _vtable_index = compute_vtable_index(resolved_klass, resolved_method,
1482 _do_itable_lookup); // out parameter
1483 assert(_vtable_index >= 0, "invalid vtable index");
1484
1485 initialize(uniqm);
1486 }
1487
1488 // Note: If n==num_participants, returns nullptr.
1489 Method* found_method(uint n) {
1490 assert(n <= num_participants(), "oob");
1491 assert(participant(n) != nullptr || n == num_participants(), "proper usage");
1492 return _found_methods[n];
1493 }
1494 };
1495
1496 Klass* LinkedConcreteMethodFinder::find_witness_in(KlassDepChange& changes) {
1497 Klass* type = changes.type();
1498
1499 assert(!is_participant(type), "only old classes are participants");
1500
1501 if (is_witness(type)) {
1502 return type;
1503 }
1504 return nullptr; // No witness found. The dependency remains unbroken.
1505 }
1506
1507 Klass* LinkedConcreteMethodFinder::find_witness_anywhere(InstanceKlass* context_type) {
1508 for (CountingClassHierarchyIterator iter(context_type); !iter.done(); iter.next()) {
1509 Klass* sub = iter.klass();
1510 if (is_witness(sub)) {
1511 return sub;
1512 }
1513 if (sub->is_instance_klass() && !InstanceKlass::cast(sub)->is_linked()) {
1514 iter.skip_subclasses(); // ignore not yet linked classes
1515 }
1516 }
1517 return nullptr; // No witness found. The dependency remains unbroken.
1518 }
1519
1520 bool LinkedConcreteMethodFinder::is_witness(Klass* k) {
1521 if (is_participant(k)) {
1522 return false; // do not report participant types
1523 } else if (k->is_instance_klass()) {
1524 InstanceKlass* ik = InstanceKlass::cast(k);
1525 if (is_concrete_klass(ik)) {
1526 Method* m = select_method(ik);
1527 return record_witness(ik, m);
1528 } else {
1529 return false; // ignore non-concrete holder class
1530 }
1531 } else {
1532 return false; // no methods to find in an array type
1533 }
1534 }
1535
1536 Method* LinkedConcreteMethodFinder::select_method(InstanceKlass* recv_klass) {
1537 Method* selected_method = nullptr;
1538 if (_do_itable_lookup) {
1539 assert(_declaring_klass->is_interface(), "sanity");
1540 bool implements_interface; // initialized by method_at_itable_or_null()
1541 selected_method = recv_klass->method_at_itable_or_null(_declaring_klass, _vtable_index,
1542 implements_interface); // out parameter
1543 assert(implements_interface, "not implemented");
1544 } else {
1545 selected_method = recv_klass->method_at_vtable(_vtable_index);
1546 }
1547 return selected_method; // nullptr when corresponding slot is empty (AbstractMethodError case)
1548 }
1549
1550 int LinkedConcreteMethodFinder::compute_vtable_index(InstanceKlass* resolved_klass, Method* resolved_method,
1551 // out parameter
1552 bool& is_itable_index) {
1553 if (resolved_klass->is_interface() && resolved_method->has_itable_index()) {
1554 is_itable_index = true;
1555 return resolved_method->itable_index();
1556 }
1557 // Check for default or miranda method first.
1558 InstanceKlass* declaring_klass = resolved_method->method_holder();
1559 if (!resolved_klass->is_interface() && declaring_klass->is_interface()) {
1560 is_itable_index = false;
1561 return resolved_klass->vtable_index_of_interface_method(resolved_method);
1562 }
1563 // At this point we are sure that resolved_method is virtual and not
1564 // a default or miranda method; therefore, it must have a valid vtable index.
1565 assert(resolved_method->has_vtable_index(), "");
1566 is_itable_index = false;
1567 return resolved_method->vtable_index();
1568 }
1569
1570 bool LinkedConcreteMethodFinder::is_concrete_klass(InstanceKlass* ik) {
1571 if (!Dependencies::is_concrete_klass(ik)) {
1572 return false; // not concrete
1573 }
1574 if (ik->is_interface()) {
1575 return false; // interfaces aren't concrete
1576 }
1577 if (!ik->is_linked()) {
1578 return false; // not yet linked classes don't have instances
1579 }
1580 return true;
1581 }
1582
1583 #ifdef ASSERT
1584 // Assert that m is inherited into ctxk, without intervening overrides.
1585 // (May return true even if this is not true, in corner cases where we punt.)
1586 bool Dependencies::verify_method_context(InstanceKlass* ctxk, Method* m) {
1587 if (m->is_private()) {
1588 return false; // Quick lose. Should not happen.
1589 }
1590 if (m->method_holder() == ctxk) {
1591 return true; // Quick win.
1592 }
1593 if (!(m->is_public() || m->is_protected())) {
1594 // The override story is complex when packages get involved.
1595 return true; // Must punt the assertion to true.
1596 }
1597 Method* lm = ctxk->lookup_method(m->name(), m->signature());
1598 if (lm == nullptr) {
1599 // It might be an interface method
1600 lm = ctxk->lookup_method_in_ordered_interfaces(m->name(), m->signature());
1601 }
1602 if (lm == m) {
1603 // Method m is inherited into ctxk.
1604 return true;
1605 }
1606 if (lm != nullptr) {
1607 if (!(lm->is_public() || lm->is_protected())) {
1608 // Method is [package-]private, so the override story is complex.
1609 return true; // Must punt the assertion to true.
1610 }
1611 if (lm->is_static()) {
1612 // Static methods don't override non-static so punt
1613 return true;
1614 }
1615 if (!Dependencies::is_concrete_method(lm, ctxk) &&
1616 !Dependencies::is_concrete_method(m, ctxk)) {
1617 // They are both non-concrete
1618 if (lm->method_holder()->is_subtype_of(m->method_holder())) {
1619 // Method m is overridden by lm, but both are non-concrete.
1620 return true;
1621 }
1622 if (lm->method_holder()->is_interface() && m->method_holder()->is_interface() &&
1623 ctxk->is_subtype_of(m->method_holder()) && ctxk->is_subtype_of(lm->method_holder())) {
1624 // Interface method defined in multiple super interfaces
1625 return true;
1626 }
1627 }
1628 }
1629 ResourceMark rm;
1630 tty->print_cr("Dependency method not found in the associated context:");
1631 tty->print_cr(" context = %s", ctxk->external_name());
1632 tty->print( " method = "); m->print_short_name(tty); tty->cr();
1633 if (lm != nullptr) {
1634 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
1635 }
1636 return false;
1637 }
1638 #endif // ASSERT
1639
1640 bool Dependencies::is_concrete_klass(Klass* k) {
1641 if (k->is_abstract()) return false;
1642 // %%% We could treat classes which are concrete but
1643 // have not yet been instantiated as virtually abstract.
1644 // This would require a deoptimization barrier on first instantiation.
1645 //if (k->is_not_instantiated()) return false;
1646 return true;
1647 }
1648
1649 bool Dependencies::is_concrete_method(Method* m, Klass* k) {
1650 // nullptr is not a concrete method.
1651 if (m == nullptr) {
1652 return false;
1653 }
1654 // Statics are irrelevant to virtual call sites.
1655 if (m->is_static()) {
1656 return false;
1657 }
1658 // Abstract methods are not concrete.
1659 if (m->is_abstract()) {
1660 return false;
1661 }
1662 // Overpass (error) methods are not concrete if k is abstract.
1663 if (m->is_overpass() && k != nullptr) {
1664 return !k->is_abstract();
1665 }
1666 // Note "true" is conservative answer: overpass clause is false if k == nullptr,
1667 // implies return true if answer depends on overpass clause.
1668 return true;
1669 }
1670
1671 Klass* Dependencies::find_finalizable_subclass(InstanceKlass* ik) {
1672 for (ClassHierarchyIterator iter(ik); !iter.done(); iter.next()) {
1673 Klass* sub = iter.klass();
1674 if (sub->has_finalizer() && !sub->is_interface()) {
1675 return sub;
1676 }
1677 }
1678 return nullptr; // not found
1679 }
1680
1681 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1682 if (k->is_abstract()) return false;
1683 // We could also return false if k does not yet appear to be
1684 // instantiated, if the VM version supports this distinction also.
1685 //if (k->is_not_instantiated()) return false;
1686 return true;
1687 }
1688
1689 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1690 return k->has_finalizable_subclass();
1691 }
1692
1693 // Any use of the contents (bytecodes) of a method must be
1694 // marked by an "evol_method" dependency, if those contents
1695 // can change. (Note: A method is always dependent on itself.)
1696 Klass* Dependencies::check_evol_method(Method* m) {
1697 assert(must_be_in_vm(), "raw oops here");
1698 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1699 // Or is there a now a breakpoint?
1700 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1701 if (m->is_old()
1702 || m->number_of_breakpoints() > 0) {
1703 return m->method_holder();
1704 } else {
1705 return nullptr;
1706 }
1707 }
1708
1709 // This is a strong assertion: It is that the given type
1710 // has no subtypes whatever. It is most useful for
1711 // optimizing checks on reflected types or on array types.
1712 // (Checks on types which are derived from real instances
1713 // can be optimized more strongly than this, because we
1714 // know that the checked type comes from a concrete type,
1715 // and therefore we can disregard abstract types.)
1716 Klass* Dependencies::check_leaf_type(InstanceKlass* ctxk) {
1717 assert(must_be_in_vm(), "raw oops here");
1718 assert_locked_or_safepoint(Compile_lock);
1719 Klass* sub = ctxk->subklass();
1720 if (sub != nullptr) {
1721 return sub;
1722 } else if (ctxk->nof_implementors() != 0) {
1723 // if it is an interface, it must be unimplemented
1724 // (if it is not an interface, nof_implementors is always zero)
1725 InstanceKlass* impl = ctxk->implementor();
1726 assert(impl != nullptr, "must be set");
1727 return impl;
1728 } else {
1729 return nullptr;
1730 }
1731 }
1732
1733 // Test the assertion that conck is the only concrete subtype* of ctxk.
1734 // The type conck itself is allowed to have have further concrete subtypes.
1735 // This allows the compiler to narrow occurrences of ctxk by conck,
1736 // when dealing with the types of actual instances.
1737 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(InstanceKlass* ctxk,
1738 Klass* conck,
1739 NewKlassDepChange* changes) {
1740 ConcreteSubtypeFinder wf(conck);
1741 Klass* k = wf.find_witness(ctxk, changes);
1742 return k;
1743 }
1744
1745
1746 // Find the unique concrete proper subtype of ctxk, or nullptr if there
1747 // is more than one concrete proper subtype. If there are no concrete
1748 // proper subtypes, return ctxk itself, whether it is concrete or not.
1749 // The returned subtype is allowed to have have further concrete subtypes.
1750 // That is, return CC1 for CX > CC1 > CC2, but nullptr for CX > { CC1, CC2 }.
1751 Klass* Dependencies::find_unique_concrete_subtype(InstanceKlass* ctxk) {
1752 ConcreteSubtypeFinder wf(ctxk); // Ignore ctxk when walking.
1753 wf.record_witnesses(1); // Record one other witness when walking.
1754 Klass* wit = wf.find_witness(ctxk);
1755 if (wit != nullptr) return nullptr; // Too many witnesses.
1756 Klass* conck = wf.participant(0);
1757 if (conck == nullptr) {
1758 return ctxk; // Return ctxk as a flag for "no subtypes".
1759 } else {
1760 #ifndef PRODUCT
1761 // Make sure the dependency mechanism will pass this discovery:
1762 if (VerifyDependencies) {
1763 // Turn off dependency tracing while actually testing deps.
1764 FlagSetting fs(_verify_in_progress, true);
1765 if (!Dependencies::is_concrete_klass(ctxk)) {
1766 guarantee(nullptr == (void *)
1767 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1768 "verify dep.");
1769 }
1770 }
1771 #endif //PRODUCT
1772 return conck;
1773 }
1774 }
1775
1776 // Try to determine whether root method in some context is concrete or not based on the information about the unique method
1777 // in that context. It exploits the fact that concrete root method is always inherited into the context when there's a unique method.
1778 // Hence, unique method holder is always a supertype of the context class when root method is concrete.
1779 // Examples for concrete_root_method
1780 // C (C.m uniqm)
1781 // |
1782 // CX (ctxk) uniqm is inherited into context.
1783 //
1784 // CX (ctxk) (CX.m uniqm) here uniqm is defined in ctxk.
1785 // Examples for !concrete_root_method
1786 // CX (ctxk)
1787 // |
1788 // C (C.m uniqm) uniqm is in subtype of ctxk.
1789 bool Dependencies::is_concrete_root_method(Method* uniqm, InstanceKlass* ctxk) {
1790 if (uniqm == nullptr) {
1791 return false; // match Dependencies::is_concrete_method() behavior
1792 }
1793 // Theoretically, the "direction" of subtype check matters here.
1794 // On one hand, in case of interface context with a single implementor, uniqm can be in a superclass of the implementor which
1795 // is not related to context class.
1796 // On another hand, uniqm could come from an interface unrelated to the context class, but right now it is not possible:
1797 // it is required that uniqm->method_holder() is the participant (uniqm->method_holder() <: ctxk), hence a default method
1798 // can't be used as unique.
1799 if (ctxk->is_interface()) {
1800 InstanceKlass* implementor = ctxk->implementor();
1801 assert(implementor != ctxk, "single implementor only"); // should have been invalidated earlier
1802 ctxk = implementor;
1803 }
1804 InstanceKlass* holder = uniqm->method_holder();
1805 assert(!holder->is_interface(), "no default methods allowed");
1806 assert(ctxk->is_subclass_of(holder) || holder->is_subclass_of(ctxk), "not related");
1807 return ctxk->is_subclass_of(holder);
1808 }
1809
1810 // If a class (or interface) has a unique concrete method uniqm, return nullptr.
1811 // Otherwise, return a class that contains an interfering method.
1812 Klass* Dependencies::check_unique_concrete_method(InstanceKlass* ctxk,
1813 Method* uniqm,
1814 NewKlassDepChange* changes) {
1815 ConcreteMethodFinder wf(uniqm, uniqm->method_holder());
1816 Klass* k = wf.find_witness(ctxk, changes);
1817 if (k != nullptr) {
1818 return k;
1819 }
1820 if (!Dependencies::is_concrete_root_method(uniqm, ctxk) || changes != nullptr) {
1821 Klass* conck = find_witness_AME(ctxk, uniqm, changes);
1822 if (conck != nullptr) {
1823 // Found a concrete subtype 'conck' which does not override abstract root method.
1824 return conck;
1825 }
1826 }
1827 return nullptr;
1828 }
1829
1830 Klass* Dependencies::check_unique_implementor(InstanceKlass* ctxk, Klass* uniqk, NewKlassDepChange* changes) {
1831 assert(ctxk->is_interface(), "sanity");
1832 assert(ctxk->nof_implementors() > 0, "no implementors");
1833 if (ctxk->nof_implementors() == 1) {
1834 assert(ctxk->implementor() == uniqk, "sanity");
1835 return nullptr;
1836 }
1837 return ctxk; // no unique implementor
1838 }
1839
1840 // Search for AME.
1841 // There are two version of checks.
1842 // 1) Spot checking version(Classload time). Newly added class is checked for AME.
1843 // Checks whether abstract/overpass method is inherited into/declared in newly added concrete class.
1844 // 2) Compile time analysis for abstract/overpass(abstract klass) root_m. The non uniqm subtrees are checked for concrete classes.
1845 Klass* Dependencies::find_witness_AME(InstanceKlass* ctxk, Method* m, KlassDepChange* changes) {
1846 if (m != nullptr) {
1847 if (changes != nullptr) {
1848 // Spot checking version.
1849 ConcreteMethodFinder wf(m);
1850 Klass* new_type = changes->as_new_klass_change()->new_type();
1851 if (wf.witnessed_reabstraction_in_supers(new_type)) {
1852 return new_type;
1853 }
1854 } else {
1855 // Note: It is required that uniqm->method_holder() is the participant (see ClassHierarchyWalker::found_method()).
1856 ConcreteSubtypeFinder wf(m->method_holder());
1857 Klass* conck = wf.find_witness(ctxk);
1858 if (conck != nullptr) {
1859 Method* cm = InstanceKlass::cast(conck)->find_instance_method(m->name(), m->signature(), Klass::PrivateLookupMode::skip);
1860 if (!Dependencies::is_concrete_method(cm, conck)) {
1861 return conck;
1862 }
1863 }
1864 }
1865 }
1866 return nullptr;
1867 }
1868
1869 // This function is used by find_unique_concrete_method(non vtable based)
1870 // to check whether subtype method overrides the base method.
1871 static bool overrides(Method* sub_m, Method* base_m) {
1872 assert(base_m != nullptr, "base method should be non null");
1873 if (sub_m == nullptr) {
1874 return false;
1875 }
1876 /**
1877 * If base_m is public or protected then sub_m always overrides.
1878 * If base_m is !public, !protected and !private (i.e. base_m is package private)
1879 * then sub_m should be in the same package as that of base_m.
1880 * For package private base_m this is conservative approach as it allows only subset of all allowed cases in
1881 * the jvm specification.
1882 **/
1883 if (base_m->is_public() || base_m->is_protected() ||
1884 base_m->method_holder()->is_same_class_package(sub_m->method_holder())) {
1885 return true;
1886 }
1887 return false;
1888 }
1889
1890 // Find the set of all non-abstract methods under ctxk that match m.
1891 // (The method m must be defined or inherited in ctxk.)
1892 // Include m itself in the set, unless it is abstract.
1893 // If this set has exactly one element, return that element.
1894 Method* Dependencies::find_unique_concrete_method(InstanceKlass* ctxk, Method* m, Klass** participant) {
1895 // Return nullptr if m is marked old; must have been a redefined method.
1896 if (m->is_old()) {
1897 return nullptr;
1898 }
1899 if (m->is_default_method()) {
1900 return nullptr; // not supported
1901 }
1902 assert(verify_method_context(ctxk, m), "proper context");
1903 ConcreteMethodFinder wf(m);
1904 wf.record_witnesses(1);
1905 Klass* wit = wf.find_witness(ctxk);
1906 if (wit != nullptr) return nullptr; // Too many witnesses.
1907 Method* fm = wf.found_method(0); // Will be nullptr if num_parts == 0.
1908 if (participant != nullptr) {
1909 (*participant) = wf.participant(0);
1910 }
1911 if (!Dependencies::is_concrete_method(fm, nullptr)) {
1912 fm = nullptr; // ignore abstract methods
1913 }
1914 if (Dependencies::is_concrete_method(m, ctxk)) {
1915 if (fm == nullptr) {
1916 // It turns out that m was always the only implementation.
1917 fm = m;
1918 } else if (fm != m) {
1919 // Two conflicting implementations after all.
1920 // (This can happen if m is inherited into ctxk and fm overrides it.)
1921 return nullptr;
1922 }
1923 } else if (Dependencies::find_witness_AME(ctxk, fm) != nullptr) {
1924 // Found a concrete subtype which does not override abstract root method.
1925 return nullptr;
1926 } else if (!overrides(fm, m)) {
1927 // Found method doesn't override abstract root method.
1928 return nullptr;
1929 }
1930 assert(Dependencies::is_concrete_root_method(fm, ctxk) == Dependencies::is_concrete_method(m, ctxk), "mismatch");
1931 #ifndef PRODUCT
1932 // Make sure the dependency mechanism will pass this discovery:
1933 if (VerifyDependencies && fm != nullptr) {
1934 guarantee(nullptr == (void *)check_unique_concrete_method(ctxk, fm),
1935 "verify dep.");
1936 }
1937 #endif //PRODUCT
1938 return fm;
1939 }
1940
1941 // If a class (or interface) has a unique concrete method uniqm, return nullptr.
1942 // Otherwise, return a class that contains an interfering method.
1943 Klass* Dependencies::check_unique_concrete_method(InstanceKlass* ctxk,
1944 Method* uniqm,
1945 Klass* resolved_klass,
1946 Method* resolved_method,
1947 KlassDepChange* changes) {
1948 assert(!ctxk->is_interface() || ctxk == resolved_klass, "sanity");
1949 assert(!resolved_method->can_be_statically_bound() || resolved_method == uniqm, "sanity");
1950 assert(resolved_klass->is_subtype_of(resolved_method->method_holder()), "sanity");
1951
1952 if (!InstanceKlass::cast(resolved_klass)->is_linked() ||
1953 !resolved_method->method_holder()->is_linked() ||
1954 resolved_method->can_be_statically_bound()) {
1955 // Dependency is redundant, but benign. Just keep it to avoid unnecessary recompilation.
1956 return nullptr; // no vtable index available
1957 }
1958
1959 LinkedConcreteMethodFinder mf(InstanceKlass::cast(resolved_klass), resolved_method, uniqm);
1960 return mf.find_witness(ctxk, changes);
1961 }
1962
1963 // Find the set of all non-abstract methods under ctxk that match m.
1964 // (The method m must be defined or inherited in ctxk.)
1965 // Include m itself in the set, unless it is abstract.
1966 // If this set has exactly one element, return that element.
1967 // Not yet linked subclasses of ctxk are ignored since they don't have any instances yet.
1968 // Additionally, resolved_klass and resolved_method complete the description of the call site being analyzed.
1969 Method* Dependencies::find_unique_concrete_method(InstanceKlass* ctxk, Method* m, Klass* resolved_klass, Method* resolved_method) {
1970 // Return nullptr if m is marked old; must have been a redefined method.
1971 if (m->is_old()) {
1972 return nullptr;
1973 }
1974 if (!InstanceKlass::cast(resolved_klass)->is_linked() ||
1975 !resolved_method->method_holder()->is_linked() ||
1976 resolved_method->can_be_statically_bound()) {
1977 return m; // nothing to do: no witness under ctxk
1978 }
1979 LinkedConcreteMethodFinder wf(InstanceKlass::cast(resolved_klass), resolved_method);
1980 assert(Dependencies::verify_method_context(ctxk, m), "proper context");
1981 wf.record_witnesses(1);
1982 Klass* wit = wf.find_witness(ctxk);
1983 if (wit != nullptr) {
1984 return nullptr; // Too many witnesses.
1985 }
1986 // p == nullptr when no participants are found (wf.num_participants() == 0).
1987 // fm == nullptr case has 2 meanings:
1988 // * when p == nullptr: no method found;
1989 // * when p != nullptr: AbstractMethodError-throwing method found.
1990 // Also, found method should always be accompanied by a participant class.
1991 Klass* p = wf.participant(0);
1992 Method* fm = wf.found_method(0);
1993 assert(fm == nullptr || p != nullptr, "no participant");
1994 // Normalize all error-throwing cases to nullptr.
1995 if (fm == Universe::throw_illegal_access_error() ||
1996 fm == Universe::throw_no_such_method_error() ||
1997 !Dependencies::is_concrete_method(fm, p)) {
1998 fm = nullptr; // error-throwing method
1999 }
2000 if (Dependencies::is_concrete_method(m, ctxk)) {
2001 if (p == nullptr) {
2002 // It turns out that m was always the only implementation.
2003 assert(fm == nullptr, "sanity");
2004 fm = m;
2005 }
2006 }
2007 #ifndef PRODUCT
2008 // Make sure the dependency mechanism will pass this discovery:
2009 if (VerifyDependencies && fm != nullptr) {
2010 guarantee(nullptr == check_unique_concrete_method(ctxk, fm, resolved_klass, resolved_method),
2011 "verify dep.");
2012 }
2013 #endif // PRODUCT
2014 assert(fm == nullptr || !fm->is_abstract(), "sanity");
2015 // Old CHA conservatively reports concrete methods in abstract classes
2016 // irrespective of whether they have concrete subclasses or not.
2017 // Also, abstract root method case is not fully supported.
2018 #ifdef ASSERT
2019 Klass* uniqp = nullptr;
2020 Method* uniqm = Dependencies::find_unique_concrete_method(ctxk, m, &uniqp);
2021 assert(uniqm == nullptr || uniqm == fm ||
2022 m->is_abstract() ||
2023 uniqm->method_holder()->is_abstract() ||
2024 (fm == nullptr && uniqm != nullptr && uniqp != nullptr && !InstanceKlass::cast(uniqp)->is_linked()),
2025 "sanity");
2026 #endif // ASSERT
2027 return fm;
2028 }
2029
2030 Klass* Dependencies::check_has_no_finalizable_subclasses(InstanceKlass* ctxk, NewKlassDepChange* changes) {
2031 InstanceKlass* search_at = ctxk;
2032 if (changes != nullptr) {
2033 search_at = changes->new_type(); // just look at the new bit
2034 }
2035 return find_finalizable_subclass(search_at);
2036 }
2037
2038 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
2039 assert(call_site != nullptr, "sanity");
2040 assert(method_handle != nullptr, "sanity");
2041 assert(call_site->is_a(vmClasses::CallSite_klass()), "sanity");
2042
2043 if (changes == nullptr) {
2044 // Validate all CallSites
2045 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
2046 return call_site->klass(); // assertion failed
2047 } else {
2048 // Validate the given CallSite
2049 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
2050 assert(method_handle != changes->method_handle(), "must be");
2051 return call_site->klass(); // assertion failed
2052 }
2053 }
2054 return nullptr; // assertion still valid
2055 }
2056
2057 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
2058 if (_verify_in_progress) return; // don't log
2059 if (witness != nullptr) {
2060 LogTarget(Debug, dependencies) lt;
2061 if (lt.is_enabled()) {
2062 LogStream ls(<);
2063 print_dependency(&ls, witness, /*verbose=*/ true);
2064 }
2065 // The following is a no-op unless logging is enabled:
2066 log_dependency(witness);
2067 }
2068 }
2069
2070 Klass* Dependencies::DepStream::check_new_klass_dependency(NewKlassDepChange* changes) {
2071 assert_locked_or_safepoint(Compile_lock);
2072 Dependencies::check_valid_dependency_type(type());
2073
2074 Klass* witness = nullptr;
2075 switch (type()) {
2076 case evol_method:
2077 witness = check_evol_method(method_argument(0));
2078 break;
2079 case leaf_type:
2080 witness = check_leaf_type(context_type());
2081 break;
2082 case abstract_with_unique_concrete_subtype:
2083 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
2084 break;
2085 case unique_concrete_method_2:
2086 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
2087 break;
2088 case unique_concrete_method_4:
2089 witness = check_unique_concrete_method(context_type(), method_argument(1), type_argument(2), method_argument(3), changes);
2090 break;
2091 case unique_implementor:
2092 witness = check_unique_implementor(context_type(), type_argument(1), changes);
2093 break;
2094 case no_finalizable_subclasses:
2095 witness = check_has_no_finalizable_subclasses(context_type(), changes);
2096 break;
2097 default:
2098 witness = nullptr;
2099 break;
2100 }
2101 trace_and_log_witness(witness);
2102 return witness;
2103 }
2104
2105 Klass* Dependencies::DepStream::check_klass_init_dependency(KlassInitDepChange* changes) {
2106 assert_locked_or_safepoint(Compile_lock);
2107 Dependencies::check_valid_dependency_type(type());
2108
2109 // No new types added. Only unique_concrete_method_4 is sensitive to class initialization changes.
2110 Klass* witness = nullptr;
2111 switch (type()) {
2112 case unique_concrete_method_4:
2113 witness = check_unique_concrete_method(context_type(), method_argument(1), type_argument(2), method_argument(3), changes);
2114 break;
2115 default:
2116 witness = nullptr;
2117 break;
2118 }
2119 trace_and_log_witness(witness);
2120 return witness;
2121 }
2122
2123 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
2124 assert_locked_or_safepoint(Compile_lock);
2125 Dependencies::check_valid_dependency_type(type());
2126
2127 if (changes != nullptr) {
2128 if (changes->is_klass_init_change()) {
2129 return check_klass_init_dependency(changes->as_klass_init_change());
2130 } else {
2131 return check_new_klass_dependency(changes->as_new_klass_change());
2132 }
2133 } else {
2134 Klass* witness = check_new_klass_dependency(nullptr);
2135 // check_klass_init_dependency duplicates check_new_klass_dependency checks when class hierarchy change info is absent.
2136 assert(witness != nullptr || check_klass_init_dependency(nullptr) == nullptr, "missed dependency");
2137 return witness;
2138 }
2139 }
2140
2141 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
2142 assert_locked_or_safepoint(Compile_lock);
2143 Dependencies::check_valid_dependency_type(type());
2144
2145 Klass* witness = nullptr;
2146 switch (type()) {
2147 case call_site_target_value:
2148 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
2149 break;
2150 default:
2151 witness = nullptr;
2152 break;
2153 }
2154 trace_and_log_witness(witness);
2155 return witness;
2156 }
2157
2158
2159 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
2160 // Handle klass dependency
2161 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
2162 return check_klass_dependency(changes.as_klass_change());
2163
2164 // Handle CallSite dependency
2165 if (changes.is_call_site_change())
2166 return check_call_site_dependency(changes.as_call_site_change());
2167
2168 // irrelevant dependency; skip it
2169 return nullptr;
2170 }
2171
2172
2173 void DepChange::print() { print_on(tty); }
2174
2175 void DepChange::print_on(outputStream* st) {
2176 int nsup = 0, nint = 0;
2177 for (ContextStream str(*this); str.next(); ) {
2178 InstanceKlass* k = str.klass();
2179 switch (str.change_type()) {
2180 case Change_new_type:
2181 st->print_cr(" dependee = %s", k->external_name());
2182 break;
2183 case Change_new_sub:
2184 if (!WizardMode) {
2185 ++nsup;
2186 } else {
2187 st->print_cr(" context super = %s", k->external_name());
2188 }
2189 break;
2190 case Change_new_impl:
2191 if (!WizardMode) {
2192 ++nint;
2193 } else {
2194 st->print_cr(" context interface = %s", k->external_name());
2195 }
2196 break;
2197 default:
2198 break;
2199 }
2200 }
2201 if (nsup + nint != 0) {
2202 st->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
2203 }
2204 }
2205
2206 void DepChange::ContextStream::start() {
2207 InstanceKlass* type = (_changes.is_klass_change() ? _changes.as_klass_change()->type() : (InstanceKlass*) nullptr);
2208 _change_type = (type == nullptr ? NO_CHANGE : Start_Klass);
2209 _klass = type;
2210 _ti_base = nullptr;
2211 _ti_index = 0;
2212 _ti_limit = 0;
2213 }
2214
2215 bool DepChange::ContextStream::next() {
2216 switch (_change_type) {
2217 case Start_Klass: // initial state; _klass is the new type
2218 _ti_base = _klass->transitive_interfaces();
2219 _ti_index = 0;
2220 _change_type = Change_new_type;
2221 return true;
2222 case Change_new_type:
2223 // fall through:
2224 _change_type = Change_new_sub;
2225 case Change_new_sub:
2226 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
2227 {
2228 _klass = _klass->java_super();
2229 if (_klass != nullptr) {
2230 return true;
2231 }
2232 }
2233 // else set up _ti_limit and fall through:
2234 _ti_limit = (_ti_base == nullptr) ? 0 : _ti_base->length();
2235 _change_type = Change_new_impl;
2236 case Change_new_impl:
2237 if (_ti_index < _ti_limit) {
2238 _klass = _ti_base->at(_ti_index++);
2239 return true;
2240 }
2241 // fall through:
2242 _change_type = NO_CHANGE; // iterator is exhausted
2243 case NO_CHANGE:
2244 break;
2245 default:
2246 ShouldNotReachHere();
2247 }
2248 return false;
2249 }
2250
2251 void KlassDepChange::initialize() {
2252 // entire transaction must be under this lock:
2253 assert_lock_strong(Compile_lock);
2254
2255 // Mark all dependee and all its superclasses
2256 // Mark transitive interfaces
2257 for (ContextStream str(*this); str.next(); ) {
2258 InstanceKlass* d = str.klass();
2259 assert(!d->is_marked_dependent(), "checking");
2260 d->set_is_marked_dependent(true);
2261 }
2262 }
2263
2264 KlassDepChange::~KlassDepChange() {
2265 // Unmark all dependee and all its superclasses
2266 // Unmark transitive interfaces
2267 for (ContextStream str(*this); str.next(); ) {
2268 InstanceKlass* d = str.klass();
2269 d->set_is_marked_dependent(false);
2270 }
2271 }
2272
2273 bool KlassDepChange::involves_context(Klass* k) {
2274 if (k == nullptr || !k->is_instance_klass()) {
2275 return false;
2276 }
2277 InstanceKlass* ik = InstanceKlass::cast(k);
2278 bool is_contained = ik->is_marked_dependent();
2279 assert(is_contained == type()->is_subtype_of(k),
2280 "correct marking of potential context types");
2281 return is_contained;
2282 }
2283
2284 void Dependencies::print_statistics() {
2285 AbstractClassHierarchyWalker::print_statistics();
2286 }
2287
2288 void AbstractClassHierarchyWalker::print_statistics() {
2289 if (UsePerfData) {
2290 jlong deps_find_witness_calls = _perf_find_witness_anywhere_calls_count->get_value();
2291 jlong deps_find_witness_steps = _perf_find_witness_anywhere_steps_count->get_value();
2292 jlong deps_find_witness_singles = _perf_find_witness_in_calls_count->get_value();
2293
2294 ttyLocker ttyl;
2295 tty->print_cr("Dependency check (find_witness) "
2296 "calls=" JLONG_FORMAT ", steps=" JLONG_FORMAT " (avg=%.1f), singles=" JLONG_FORMAT,
2297 deps_find_witness_calls,
2298 deps_find_witness_steps,
2299 (double)deps_find_witness_steps / deps_find_witness_calls,
2300 deps_find_witness_singles);
2301 if (xtty != nullptr) {
2302 xtty->elem("deps_find_witness calls='" JLONG_FORMAT "' steps='" JLONG_FORMAT "' singles='" JLONG_FORMAT "'",
2303 deps_find_witness_calls,
2304 deps_find_witness_steps,
2305 deps_find_witness_singles);
2306 }
2307 }
2308 }
2309
2310 CallSiteDepChange::CallSiteDepChange(Handle call_site, Handle method_handle) :
2311 _call_site(call_site),
2312 _method_handle(method_handle) {
2313 assert(_call_site()->is_a(vmClasses::CallSite_klass()), "must be");
2314 assert(_method_handle.is_null() || _method_handle()->is_a(vmClasses::MethodHandle_klass()), "must be");
2315 }
2316
2317 void dependencies_init() {
2318 AbstractClassHierarchyWalker::init();
2319 }