1 /*
2 * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciArrayKlass.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "ci/ciKlass.hpp"
29 #include "ci/ciMethod.hpp"
30 #include "code/dependencies.hpp"
31 #include "compiler/compileLog.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "runtime/handles.inline.hpp"
34 #include "utilities/copy.hpp"
35
36
37 #ifdef ASSERT
38 static bool must_be_in_vm() {
39 Thread* thread = Thread::current();
40 if (thread->is_Java_thread())
41 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
42 else
43 return true; //something like this: thread->is_VM_thread();
44 }
45 #endif //ASSERT
46
47 void Dependencies::initialize(ciEnv* env) {
48 Arena* arena = env->arena();
49 _oop_recorder = env->oop_recorder();
50 _log = env->log();
51 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
52 DEBUG_ONLY(_deps[end_marker] = NULL);
53 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
54 _deps[i] = new(arena) GrowableArray<ciObject*>(arena, 10, 0, 0);
55 }
56 _content_bytes = NULL;
57 _size_in_bytes = (size_t)-1;
58
59 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
60 }
61
62 void Dependencies::assert_evol_method(ciMethod* m) {
63 assert_common_1(evol_method, m);
64 }
65
66 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
67 if (ctxk->is_array_klass()) {
68 // As a special case, support this assertion on an array type,
69 // which reduces to an assertion on its element type.
70 // Note that this cannot be done with assertions that
71 // relate to concreteness or abstractness.
72 ciType* elemt = ctxk->as_array_klass()->base_element_type();
73 if (!elemt->is_instance_klass()) return; // Ex: int[][]
74 ctxk = elemt->as_instance_klass();
75 //if (ctxk->is_final()) return; // Ex: String[][]
76 }
77 check_ctxk(ctxk);
78 assert_common_1(leaf_type, ctxk);
79 }
80
81 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
82 check_ctxk_abstract(ctxk);
83 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
84 }
85
86 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
87 check_ctxk_abstract(ctxk);
88 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
89 }
90
91 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
92 check_ctxk_concrete(ctxk);
93 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
94 }
95
96 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
97 check_ctxk(ctxk);
98 assert_common_2(unique_concrete_method, ctxk, uniqm);
99 }
100
101 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
102 check_ctxk(ctxk);
103 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
104 }
105
106 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
107 check_ctxk(ctxk);
108 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
109 }
110
111 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
112 check_ctxk(ctxk);
113 assert_common_1(no_finalizable_subclasses, ctxk);
114 }
115
116 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
117 check_ctxk(call_site->klass());
118 assert_common_2(call_site_target_value, call_site, method_handle);
119 }
120
121 // Helper function. If we are adding a new dep. under ctxk2,
122 // try to find an old dep. under a broader* ctxk1. If there is
123 //
124 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciObject*>* deps,
125 int ctxk_i, ciKlass* ctxk2) {
126 ciKlass* ctxk1 = deps->at(ctxk_i)->as_klass();
127 if (ctxk2->is_subtype_of(ctxk1)) {
128 return true; // success, and no need to change
129 } else if (ctxk1->is_subtype_of(ctxk2)) {
130 // new context class fully subsumes previous one
131 deps->at_put(ctxk_i, ctxk2);
132 return true;
133 } else {
134 return false;
135 }
136 }
137
138 void Dependencies::assert_common_1(DepType dept, ciObject* x) {
139 assert(dep_args(dept) == 1, "sanity");
140 log_dependency(dept, x);
141 GrowableArray<ciObject*>* deps = _deps[dept];
142
143 // see if the same (or a similar) dep is already recorded
144 if (note_dep_seen(dept, x)) {
145 assert(deps->find(x) >= 0, "sanity");
146 } else {
147 deps->append(x);
148 }
149 }
150
151 void Dependencies::assert_common_2(DepType dept,
152 ciObject* x0, ciObject* x1) {
153 assert(dep_args(dept) == 2, "sanity");
154 log_dependency(dept, x0, x1);
155 GrowableArray<ciObject*>* deps = _deps[dept];
156
157 // see if the same (or a similar) dep is already recorded
158 bool has_ctxk = has_explicit_context_arg(dept);
159 if (has_ctxk) {
160 assert(dep_context_arg(dept) == 0, "sanity");
161 if (note_dep_seen(dept, x1)) {
162 // look in this bucket for redundant assertions
163 const int stride = 2;
164 for (int i = deps->length(); (i -= stride) >= 0; ) {
165 ciObject* y1 = deps->at(i+1);
166 if (x1 == y1) { // same subject; check the context
167 if (maybe_merge_ctxk(deps, i+0, x0->as_klass())) {
168 return;
169 }
170 }
171 }
172 }
173 } else {
174 assert(dep_implicit_context_arg(dept) == 0, "sanity");
175 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
176 // look in this bucket for redundant assertions
177 const int stride = 2;
178 for (int i = deps->length(); (i -= stride) >= 0; ) {
179 ciObject* y0 = deps->at(i+0);
180 ciObject* y1 = deps->at(i+1);
181 if (x0 == y0 && x1 == y1) {
182 return;
183 }
184 }
185 }
186 }
187
188 // append the assertion in the correct bucket:
189 deps->append(x0);
190 deps->append(x1);
191 }
192
193 void Dependencies::assert_common_3(DepType dept,
194 ciKlass* ctxk, ciObject* x, ciObject* x2) {
195 assert(dep_context_arg(dept) == 0, "sanity");
196 assert(dep_args(dept) == 3, "sanity");
197 log_dependency(dept, ctxk, x, x2);
198 GrowableArray<ciObject*>* deps = _deps[dept];
199
200 // try to normalize an unordered pair:
201 bool swap = false;
202 switch (dept) {
203 case abstract_with_exclusive_concrete_subtypes_2:
204 swap = (x->ident() > x2->ident() && x != ctxk);
205 break;
206 case exclusive_concrete_methods_2:
207 swap = (x->ident() > x2->ident() && x->as_method()->holder() != ctxk);
208 break;
209 }
210 if (swap) { ciObject* t = x; x = x2; x2 = t; }
211
212 // see if the same (or a similar) dep is already recorded
213 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
214 // look in this bucket for redundant assertions
215 const int stride = 3;
216 for (int i = deps->length(); (i -= stride) >= 0; ) {
217 ciObject* y = deps->at(i+1);
218 ciObject* y2 = deps->at(i+2);
219 if (x == y && x2 == y2) { // same subjects; check the context
220 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
221 return;
222 }
223 }
224 }
225 }
226 // append the assertion in the correct bucket:
227 deps->append(ctxk);
228 deps->append(x);
229 deps->append(x2);
230 }
231
232 /// Support for encoding dependencies into an nmethod:
233
234 void Dependencies::copy_to(nmethod* nm) {
235 address beg = nm->dependencies_begin();
236 address end = nm->dependencies_end();
237 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
238 Copy::disjoint_words((HeapWord*) content_bytes(),
239 (HeapWord*) beg,
240 size_in_bytes() / sizeof(HeapWord));
241 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
242 }
243
244 static int sort_dep(ciObject** p1, ciObject** p2, int narg) {
245 for (int i = 0; i < narg; i++) {
246 int diff = p1[i]->ident() - p2[i]->ident();
247 if (diff != 0) return diff;
248 }
249 return 0;
250 }
251 static int sort_dep_arg_1(ciObject** p1, ciObject** p2)
252 { return sort_dep(p1, p2, 1); }
253 static int sort_dep_arg_2(ciObject** p1, ciObject** p2)
254 { return sort_dep(p1, p2, 2); }
255 static int sort_dep_arg_3(ciObject** p1, ciObject** p2)
256 { return sort_dep(p1, p2, 3); }
257
258 void Dependencies::sort_all_deps() {
259 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
260 DepType dept = (DepType)deptv;
261 GrowableArray<ciObject*>* deps = _deps[dept];
262 if (deps->length() <= 1) continue;
263 switch (dep_args(dept)) {
264 case 1: deps->sort(sort_dep_arg_1, 1); break;
265 case 2: deps->sort(sort_dep_arg_2, 2); break;
266 case 3: deps->sort(sort_dep_arg_3, 3); break;
267 default: ShouldNotReachHere();
268 }
269 }
270 }
271
272 size_t Dependencies::estimate_size_in_bytes() {
273 size_t est_size = 100;
274 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
275 DepType dept = (DepType)deptv;
276 GrowableArray<ciObject*>* deps = _deps[dept];
277 est_size += deps->length()*2; // tags and argument(s)
278 }
279 return est_size;
280 }
281
282 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciObject* x) {
283 switch (dept) {
284 case abstract_with_exclusive_concrete_subtypes_2:
285 return x->as_klass();
286 case unique_concrete_method:
287 case exclusive_concrete_methods_2:
288 return x->as_method()->holder();
289 }
290 return NULL; // let NULL be NULL
291 }
292
293 klassOop Dependencies::ctxk_encoded_as_null(DepType dept, oop x) {
294 assert(must_be_in_vm(), "raw oops here");
295 switch (dept) {
296 case abstract_with_exclusive_concrete_subtypes_2:
297 assert(x->is_klass(), "sanity");
298 return (klassOop) x;
299 case unique_concrete_method:
300 case exclusive_concrete_methods_2:
301 assert(x->is_method(), "sanity");
302 return ((methodOop)x)->method_holder();
303 }
304 return NULL; // let NULL be NULL
305 }
306
307 void Dependencies::encode_content_bytes() {
308 sort_all_deps();
309
310 // cast is safe, no deps can overflow INT_MAX
311 CompressedWriteStream bytes((int)estimate_size_in_bytes());
312
313 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
314 DepType dept = (DepType)deptv;
315 GrowableArray<ciObject*>* deps = _deps[dept];
316 if (deps->length() == 0) continue;
317 int stride = dep_args(dept);
318 int ctxkj = dep_context_arg(dept); // -1 if no context arg
319 assert(stride > 0, "sanity");
320 for (int i = 0; i < deps->length(); i += stride) {
321 jbyte code_byte = (jbyte)dept;
322 int skipj = -1;
323 if (ctxkj >= 0 && ctxkj+1 < stride) {
324 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_klass();
325 ciObject* x = deps->at(i+ctxkj+1); // following argument
326 if (ctxk == ctxk_encoded_as_null(dept, x)) {
327 skipj = ctxkj; // we win: maybe one less oop to keep track of
328 code_byte |= default_context_type_bit;
329 }
330 }
331 bytes.write_byte(code_byte);
332 for (int j = 0; j < stride; j++) {
333 if (j == skipj) continue;
334 bytes.write_int(_oop_recorder->find_index(deps->at(i+j)->constant_encoding()));
335 }
336 }
337 }
338
339 // write a sentinel byte to mark the end
340 bytes.write_byte(end_marker);
341
342 // round it out to a word boundary
343 while (bytes.position() % sizeof(HeapWord) != 0) {
344 bytes.write_byte(end_marker);
345 }
346
347 // check whether the dept byte encoding really works
348 assert((jbyte)default_context_type_bit != 0, "byte overflow");
349
350 _content_bytes = bytes.buffer();
351 _size_in_bytes = bytes.position();
352 }
353
354
355 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
356 "end_marker",
357 "evol_method",
358 "leaf_type",
359 "abstract_with_unique_concrete_subtype",
360 "abstract_with_no_concrete_subtype",
361 "concrete_with_no_concrete_subtype",
362 "unique_concrete_method",
363 "abstract_with_exclusive_concrete_subtypes_2",
364 "exclusive_concrete_methods_2",
365 "no_finalizable_subclasses",
366 "call_site_target_value"
367 };
368
369 int Dependencies::_dep_args[TYPE_LIMIT] = {
370 -1,// end_marker
371 1, // evol_method m
372 1, // leaf_type ctxk
373 2, // abstract_with_unique_concrete_subtype ctxk, k
374 1, // abstract_with_no_concrete_subtype ctxk
375 1, // concrete_with_no_concrete_subtype ctxk
376 2, // unique_concrete_method ctxk, m
377 3, // unique_concrete_subtypes_2 ctxk, k1, k2
378 3, // unique_concrete_methods_2 ctxk, m1, m2
379 1, // no_finalizable_subclasses ctxk
380 2 // call_site_target_value call_site, method_handle
381 };
382
383 const char* Dependencies::dep_name(Dependencies::DepType dept) {
384 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
385 return _dep_name[dept];
386 }
387
388 int Dependencies::dep_args(Dependencies::DepType dept) {
389 if (!dept_in_mask(dept, all_types)) return -1;
390 return _dep_args[dept];
391 }
392
393 void Dependencies::check_valid_dependency_type(DepType dept) {
394 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
395 }
396
397 // for the sake of the compiler log, print out current dependencies:
398 void Dependencies::log_all_dependencies() {
399 if (log() == NULL) return;
400 ciObject* args[max_arg_count];
401 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
402 DepType dept = (DepType)deptv;
403 GrowableArray<ciObject*>* deps = _deps[dept];
404 if (deps->length() == 0) continue;
405 int stride = dep_args(dept);
406 for (int i = 0; i < deps->length(); i += stride) {
407 for (int j = 0; j < stride; j++) {
408 // flush out the identities before printing
409 args[j] = deps->at(i+j);
410 }
411 write_dependency_to(log(), dept, stride, args);
412 }
413 }
414 }
415
416 void Dependencies::write_dependency_to(CompileLog* log,
417 DepType dept,
418 int nargs, oop args[],
419 klassOop witness) {
420 if (log == NULL) {
421 return;
422 }
423 ciEnv* env = ciEnv::current();
424 ciObject* ciargs[max_arg_count];
425 assert(nargs <= max_arg_count, "oob");
426 for (int j = 0; j < nargs; j++) {
427 ciargs[j] = env->get_object(args[j]);
428 }
429 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
430 }
431
432 void Dependencies::write_dependency_to(CompileLog* log,
433 DepType dept,
434 int nargs, ciObject* args[],
435 klassOop witness) {
436 if (log == NULL) return;
437 assert(nargs <= max_arg_count, "oob");
438 int argids[max_arg_count];
439 int ctxkj = dep_context_arg(dept); // -1 if no context arg
440 int j;
441 for (j = 0; j < nargs; j++) {
442 argids[j] = log->identify(args[j]);
443 }
444 if (witness != NULL) {
445 log->begin_elem("dependency_failed");
446 } else {
447 log->begin_elem("dependency");
448 }
449 log->print(" type='%s'", dep_name(dept));
450 if (ctxkj >= 0) {
451 log->print(" ctxk='%d'", argids[ctxkj]);
452 }
453 // write remaining arguments, if any.
454 for (j = 0; j < nargs; j++) {
455 if (j == ctxkj) continue; // already logged
456 if (j == 1) {
457 log->print( " x='%d'", argids[j]);
458 } else {
459 log->print(" x%d='%d'", j, argids[j]);
460 }
461 }
462 if (witness != NULL) {
463 log->object("witness", witness);
464 log->stamp();
465 }
466 log->end_elem();
467 }
468
469 void Dependencies::write_dependency_to(xmlStream* xtty,
470 DepType dept,
471 int nargs, oop args[],
472 klassOop witness) {
473 if (xtty == NULL) return;
474 ttyLocker ttyl;
475 int ctxkj = dep_context_arg(dept); // -1 if no context arg
476 if (witness != NULL) {
477 xtty->begin_elem("dependency_failed");
478 } else {
479 xtty->begin_elem("dependency");
480 }
481 xtty->print(" type='%s'", dep_name(dept));
482 if (ctxkj >= 0) {
483 xtty->object("ctxk", args[ctxkj]);
484 }
485 // write remaining arguments, if any.
486 for (int j = 0; j < nargs; j++) {
487 if (j == ctxkj) continue; // already logged
488 if (j == 1) {
489 xtty->object("x", args[j]);
490 } else {
491 char xn[10]; sprintf(xn, "x%d", j);
492 xtty->object(xn, args[j]);
493 }
494 }
495 if (witness != NULL) {
496 xtty->object("witness", witness);
497 xtty->stamp();
498 }
499 xtty->end_elem();
500 }
501
502 void Dependencies::print_dependency(DepType dept, int nargs, oop args[],
503 klassOop witness) {
504 ResourceMark rm;
505 ttyLocker ttyl; // keep the following output all in one block
506 tty->print_cr("%s of type %s",
507 (witness == NULL)? "Dependency": "Failed dependency",
508 dep_name(dept));
509 // print arguments
510 int ctxkj = dep_context_arg(dept); // -1 if no context arg
511 for (int j = 0; j < nargs; j++) {
512 oop arg = args[j];
513 bool put_star = false;
514 if (arg == NULL) continue;
515 const char* what;
516 if (j == ctxkj) {
517 what = "context";
518 put_star = !Dependencies::is_concrete_klass((klassOop)arg);
519 } else if (arg->is_method()) {
520 what = "method ";
521 put_star = !Dependencies::is_concrete_method((methodOop)arg);
522 } else if (arg->is_klass()) {
523 what = "class ";
524 } else {
525 what = "object ";
526 }
527 tty->print(" %s = %s", what, (put_star? "*": ""));
528 if (arg->is_klass())
529 tty->print("%s", Klass::cast((klassOop)arg)->external_name());
530 else
531 arg->print_value();
532 tty->cr();
533 }
534 if (witness != NULL) {
535 bool put_star = !Dependencies::is_concrete_klass(witness);
536 tty->print_cr(" witness = %s%s",
537 (put_star? "*": ""),
538 Klass::cast(witness)->external_name());
539 }
540 }
541
542 void Dependencies::DepStream::log_dependency(klassOop witness) {
543 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
544 int nargs = argument_count();
545 oop args[max_arg_count];
546 for (int j = 0; j < nargs; j++) {
547 args[j] = argument(j);
548 }
549 if (_deps != NULL && _deps->log() != NULL) {
550 Dependencies::write_dependency_to(_deps->log(),
551 type(), nargs, args, witness);
552 } else {
553 Dependencies::write_dependency_to(xtty,
554 type(), nargs, args, witness);
555 }
556 }
557
558 void Dependencies::DepStream::print_dependency(klassOop witness, bool verbose) {
559 int nargs = argument_count();
560 oop args[max_arg_count];
561 for (int j = 0; j < nargs; j++) {
562 args[j] = argument(j);
563 }
564 Dependencies::print_dependency(type(), nargs, args, witness);
565 if (verbose) {
566 if (_code != NULL) {
567 tty->print(" code: ");
568 _code->print_value_on(tty);
569 tty->cr();
570 }
571 }
572 }
573
574
575 /// Dependency stream support (decodes dependencies from an nmethod):
576
577 #ifdef ASSERT
578 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
579 assert(must_be_in_vm(), "raw oops here");
580 _byte_limit = byte_limit;
581 _type = (DepType)(end_marker-1); // defeat "already at end" assert
582 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
583 }
584 #endif //ASSERT
585
586 bool Dependencies::DepStream::next() {
587 assert(_type != end_marker, "already at end");
588 if (_bytes.position() == 0 && _code != NULL
589 && _code->dependencies_size() == 0) {
590 // Method has no dependencies at all.
591 return false;
592 }
593 int code_byte = (_bytes.read_byte() & 0xFF);
594 if (code_byte == end_marker) {
595 DEBUG_ONLY(_type = end_marker);
596 return false;
597 } else {
598 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
599 code_byte -= ctxk_bit;
600 DepType dept = (DepType)code_byte;
601 _type = dept;
602 Dependencies::check_valid_dependency_type(dept);
603 int stride = _dep_args[dept];
604 assert(stride == dep_args(dept), "sanity");
605 int skipj = -1;
606 if (ctxk_bit != 0) {
607 skipj = 0; // currently the only context argument is at zero
608 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
609 }
610 for (int j = 0; j < stride; j++) {
611 _xi[j] = (j == skipj)? 0: _bytes.read_int();
612 }
613 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
614 return true;
615 }
616 }
617
618 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
619 return (_code != NULL)
620 ? _code->oop_at(i)
621 : JNIHandles::resolve(_deps->oop_recorder()->handle_at(i));
622 }
623
624 oop Dependencies::DepStream::argument(int i) {
625 return recorded_oop_at(argument_index(i));
626 }
627
628 klassOop Dependencies::DepStream::context_type() {
629 assert(must_be_in_vm(), "raw oops here");
630
631 // Most dependencies have an explicit context type argument.
632 {
633 int ctxkj = dep_context_arg(_type); // -1 if no explicit context arg
634 if (ctxkj >= 0) {
635 oop k = argument(ctxkj);
636 if (k != NULL) { // context type was not compressed away
637 assert(k->is_klass(), "type check");
638 return (klassOop) k;
639 }
640 // recompute "default" context type
641 return ctxk_encoded_as_null(_type, argument(ctxkj+1));
642 }
643 }
644
645 // Some dependencies are using the klass of the first object
646 // argument as implicit context type (e.g. call_site_target_value).
647 {
648 int ctxkj = dep_implicit_context_arg(_type);
649 if (ctxkj >= 0) {
650 oop k = argument(ctxkj)->klass();
651 assert(k->is_klass(), "type check");
652 return (klassOop) k;
653 }
654 }
655
656 // And some dependencies don't have a context type at all,
657 // e.g. evol_method.
658 return NULL;
659 }
660
661 /// Checking dependencies:
662
663 // This hierarchy walker inspects subtypes of a given type,
664 // trying to find a "bad" class which breaks a dependency.
665 // Such a class is called a "witness" to the broken dependency.
666 // While searching around, we ignore "participants", which
667 // are already known to the dependency.
668 class ClassHierarchyWalker {
669 public:
670 enum { PARTICIPANT_LIMIT = 3 };
671
672 private:
673 // optional method descriptor to check for:
674 Symbol* _name;
675 Symbol* _signature;
676
677 // special classes which are not allowed to be witnesses:
678 klassOop _participants[PARTICIPANT_LIMIT+1];
679 int _num_participants;
680
681 // cache of method lookups
682 methodOop _found_methods[PARTICIPANT_LIMIT+1];
683
684 // if non-zero, tells how many witnesses to convert to participants
685 int _record_witnesses;
686
687 void initialize(klassOop participant) {
688 _record_witnesses = 0;
689 _participants[0] = participant;
690 _found_methods[0] = NULL;
691 _num_participants = 0;
692 if (participant != NULL) {
693 // Terminating NULL.
694 _participants[1] = NULL;
695 _found_methods[1] = NULL;
696 _num_participants = 1;
697 }
698 }
699
700 void initialize_from_method(methodOop m) {
701 assert(m != NULL && m->is_method(), "sanity");
702 _name = m->name();
703 _signature = m->signature();
704 }
705
706 public:
707 // The walker is initialized to recognize certain methods and/or types
708 // as friendly participants.
709 ClassHierarchyWalker(klassOop participant, methodOop m) {
710 initialize_from_method(m);
711 initialize(participant);
712 }
713 ClassHierarchyWalker(methodOop m) {
714 initialize_from_method(m);
715 initialize(NULL);
716 }
717 ClassHierarchyWalker(klassOop participant = NULL) {
718 _name = NULL;
719 _signature = NULL;
720 initialize(participant);
721 }
722
723 // This is common code for two searches: One for concrete subtypes,
724 // the other for concrete method implementations and overrides.
725 bool doing_subtype_search() {
726 return _name == NULL;
727 }
728
729 int num_participants() { return _num_participants; }
730 klassOop participant(int n) {
731 assert((uint)n <= (uint)_num_participants, "oob");
732 return _participants[n];
733 }
734
735 // Note: If n==num_participants, returns NULL.
736 methodOop found_method(int n) {
737 assert((uint)n <= (uint)_num_participants, "oob");
738 methodOop fm = _found_methods[n];
739 assert(n == _num_participants || fm != NULL, "proper usage");
740 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
741 return fm;
742 }
743
744 #ifdef ASSERT
745 // Assert that m is inherited into ctxk, without intervening overrides.
746 // (May return true even if this is not true, in corner cases where we punt.)
747 bool check_method_context(klassOop ctxk, methodOop m) {
748 if (m->method_holder() == ctxk)
749 return true; // Quick win.
750 if (m->is_private())
751 return false; // Quick lose. Should not happen.
752 if (!(m->is_public() || m->is_protected()))
753 // The override story is complex when packages get involved.
754 return true; // Must punt the assertion to true.
755 Klass* k = Klass::cast(ctxk);
756 methodOop lm = k->lookup_method(m->name(), m->signature());
757 if (lm == NULL && k->oop_is_instance()) {
758 // It might be an abstract interface method, devoid of mirandas.
759 lm = ((instanceKlass*)k)->lookup_method_in_all_interfaces(m->name(),
760 m->signature());
761 }
762 if (lm == m)
763 // Method m is inherited into ctxk.
764 return true;
765 if (lm != NULL) {
766 if (!(lm->is_public() || lm->is_protected()))
767 // Method is [package-]private, so the override story is complex.
768 return true; // Must punt the assertion to true.
769 if ( !Dependencies::is_concrete_method(lm)
770 && !Dependencies::is_concrete_method(m)
771 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder()))
772 // Method m is overridden by lm, but both are non-concrete.
773 return true;
774 }
775 ResourceMark rm;
776 tty->print_cr("Dependency method not found in the associated context:");
777 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name());
778 tty->print( " method = "); m->print_short_name(tty); tty->cr();
779 if (lm != NULL) {
780 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
781 }
782 return false;
783 }
784 #endif
785
786 void add_participant(klassOop participant) {
787 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
788 int np = _num_participants++;
789 _participants[np] = participant;
790 _participants[np+1] = NULL;
791 _found_methods[np+1] = NULL;
792 }
793
794 void record_witnesses(int add) {
795 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
796 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
797 _record_witnesses = add;
798 }
799
800 bool is_witness(klassOop k) {
801 if (doing_subtype_search()) {
802 return Dependencies::is_concrete_klass(k);
803 } else {
804 methodOop m = instanceKlass::cast(k)->find_method(_name, _signature);
805 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
806 _found_methods[_num_participants] = m;
807 // Note: If add_participant(k) is called,
808 // the method m will already be memoized for it.
809 return true;
810 }
811 }
812
813 bool is_participant(klassOop k) {
814 if (k == _participants[0]) {
815 return true;
816 } else if (_num_participants <= 1) {
817 return false;
818 } else {
819 return in_list(k, &_participants[1]);
820 }
821 }
822 bool ignore_witness(klassOop witness) {
823 if (_record_witnesses == 0) {
824 return false;
825 } else {
826 --_record_witnesses;
827 add_participant(witness);
828 return true;
829 }
830 }
831 static bool in_list(klassOop x, klassOop* list) {
832 for (int i = 0; ; i++) {
833 klassOop y = list[i];
834 if (y == NULL) break;
835 if (y == x) return true;
836 }
837 return false; // not in list
838 }
839
840 private:
841 // the actual search method:
842 klassOop find_witness_anywhere(klassOop context_type,
843 bool participants_hide_witnesses,
844 bool top_level_call = true);
845 // the spot-checking version:
846 klassOop find_witness_in(KlassDepChange& changes,
847 klassOop context_type,
848 bool participants_hide_witnesses);
849 public:
850 klassOop find_witness_subtype(klassOop context_type, KlassDepChange* changes = NULL) {
851 assert(doing_subtype_search(), "must set up a subtype search");
852 // When looking for unexpected concrete types,
853 // do not look beneath expected ones.
854 const bool participants_hide_witnesses = true;
855 // CX > CC > C' is OK, even if C' is new.
856 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
857 if (changes != NULL) {
858 return find_witness_in(*changes, context_type, participants_hide_witnesses);
859 } else {
860 return find_witness_anywhere(context_type, participants_hide_witnesses);
861 }
862 }
863 klassOop find_witness_definer(klassOop context_type, KlassDepChange* changes = NULL) {
864 assert(!doing_subtype_search(), "must set up a method definer search");
865 // When looking for unexpected concrete methods,
866 // look beneath expected ones, to see if there are overrides.
867 const bool participants_hide_witnesses = true;
868 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
869 if (changes != NULL) {
870 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
871 } else {
872 return find_witness_anywhere(context_type, !participants_hide_witnesses);
873 }
874 }
875 };
876
877 #ifndef PRODUCT
878 static int deps_find_witness_calls = 0;
879 static int deps_find_witness_steps = 0;
880 static int deps_find_witness_recursions = 0;
881 static int deps_find_witness_singles = 0;
882 static int deps_find_witness_print = 0; // set to -1 to force a final print
883 static bool count_find_witness_calls() {
884 if (TraceDependencies || LogCompilation) {
885 int pcount = deps_find_witness_print + 1;
886 bool final_stats = (pcount == 0);
887 bool initial_call = (pcount == 1);
888 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
889 if (pcount < 0) pcount = 1; // crude overflow protection
890 deps_find_witness_print = pcount;
891 if (VerifyDependencies && initial_call) {
892 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
893 }
894 if (occasional_print || final_stats) {
895 // Every now and then dump a little info about dependency searching.
896 if (xtty != NULL) {
897 ttyLocker ttyl;
898 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
899 deps_find_witness_calls,
900 deps_find_witness_steps,
901 deps_find_witness_recursions,
902 deps_find_witness_singles);
903 }
904 if (final_stats || (TraceDependencies && WizardMode)) {
905 ttyLocker ttyl;
906 tty->print_cr("Dependency check (find_witness) "
907 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
908 deps_find_witness_calls,
909 deps_find_witness_steps,
910 (double)deps_find_witness_steps / deps_find_witness_calls,
911 deps_find_witness_recursions,
912 deps_find_witness_singles);
913 }
914 }
915 return true;
916 }
917 return false;
918 }
919 #else
920 #define count_find_witness_calls() (0)
921 #endif //PRODUCT
922
923
924 klassOop ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
925 klassOop context_type,
926 bool participants_hide_witnesses) {
927 assert(changes.involves_context(context_type), "irrelevant dependency");
928 klassOop new_type = changes.new_type();
929
930 count_find_witness_calls();
931 NOT_PRODUCT(deps_find_witness_singles++);
932
933 // Current thread must be in VM (not native mode, as in CI):
934 assert(must_be_in_vm(), "raw oops here");
935 // Must not move the class hierarchy during this check:
936 assert_locked_or_safepoint(Compile_lock);
937
938 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
939 if (nof_impls > 1) {
940 // Avoid this case: *I.m > { A.m, C }; B.m > C
941 // %%% Until this is fixed more systematically, bail out.
942 // See corresponding comment in find_witness_anywhere.
943 return context_type;
944 }
945
946 assert(!is_participant(new_type), "only old classes are participants");
947 if (participants_hide_witnesses) {
948 // If the new type is a subtype of a participant, we are done.
949 for (int i = 0; i < num_participants(); i++) {
950 klassOop part = participant(i);
951 if (part == NULL) continue;
952 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part),
953 "correct marking of participants, b/c new_type is unique");
954 if (changes.involves_context(part)) {
955 // new guy is protected from this check by previous participant
956 return NULL;
957 }
958 }
959 }
960
961 if (is_witness(new_type) &&
962 !ignore_witness(new_type)) {
963 return new_type;
964 }
965
966 return NULL;
967 }
968
969
970 // Walk hierarchy under a context type, looking for unexpected types.
971 // Do not report participant types, and recursively walk beneath
972 // them only if participants_hide_witnesses is false.
973 // If top_level_call is false, skip testing the context type,
974 // because the caller has already considered it.
975 klassOop ClassHierarchyWalker::find_witness_anywhere(klassOop context_type,
976 bool participants_hide_witnesses,
977 bool top_level_call) {
978 // Current thread must be in VM (not native mode, as in CI):
979 assert(must_be_in_vm(), "raw oops here");
980 // Must not move the class hierarchy during this check:
981 assert_locked_or_safepoint(Compile_lock);
982
983 bool do_counts = count_find_witness_calls();
984
985 // Check the root of the sub-hierarchy first.
986 if (top_level_call) {
987 if (do_counts) {
988 NOT_PRODUCT(deps_find_witness_calls++);
989 NOT_PRODUCT(deps_find_witness_steps++);
990 }
991 if (is_participant(context_type)) {
992 if (participants_hide_witnesses) return NULL;
993 // else fall through to search loop...
994 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
995 // The context is an abstract class or interface, to start with.
996 return context_type;
997 }
998 }
999
1000 // Now we must check each implementor and each subclass.
1001 // Use a short worklist to avoid blowing the stack.
1002 // Each worklist entry is a *chain* of subklass siblings to process.
1003 const int CHAINMAX = 100; // >= 1 + instanceKlass::implementors_limit
1004 Klass* chains[CHAINMAX];
1005 int chaini = 0; // index into worklist
1006 Klass* chain; // scratch variable
1007 #define ADD_SUBCLASS_CHAIN(k) { \
1008 assert(chaini < CHAINMAX, "oob"); \
1009 chain = instanceKlass::cast(k)->subklass(); \
1010 if (chain != NULL) chains[chaini++] = chain; }
1011
1012 // Look for non-abstract subclasses.
1013 // (Note: Interfaces do not have subclasses.)
1014 ADD_SUBCLASS_CHAIN(context_type);
1015
1016 // If it is an interface, search its direct implementors.
1017 // (Their subclasses are additional indirect implementors.
1018 // See instanceKlass::add_implementor.)
1019 // (Note: nof_implementors is always zero for non-interfaces.)
1020 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
1021 if (nof_impls > 1) {
1022 // Avoid this case: *I.m > { A.m, C }; B.m > C
1023 // Here, I.m has 2 concrete implementations, but m appears unique
1024 // as A.m, because the search misses B.m when checking C.
1025 // The inherited method B.m was getting missed by the walker
1026 // when interface 'I' was the starting point.
1027 // %%% Until this is fixed more systematically, bail out.
1028 // (Old CHA had the same limitation.)
1029 return context_type;
1030 }
1031 for (int i = 0; i < nof_impls; i++) {
1032 klassOop impl = instanceKlass::cast(context_type)->implementor(i);
1033 if (impl == NULL) {
1034 // implementors array overflowed => no exact info.
1035 return context_type; // report an inexact witness to this sad affair
1036 }
1037 if (do_counts)
1038 { NOT_PRODUCT(deps_find_witness_steps++); }
1039 if (is_participant(impl)) {
1040 if (participants_hide_witnesses) continue;
1041 // else fall through to process this guy's subclasses
1042 } else if (is_witness(impl) && !ignore_witness(impl)) {
1043 return impl;
1044 }
1045 ADD_SUBCLASS_CHAIN(impl);
1046 }
1047
1048 // Recursively process each non-trivial sibling chain.
1049 while (chaini > 0) {
1050 Klass* chain = chains[--chaini];
1051 for (Klass* subk = chain; subk != NULL; subk = subk->next_sibling()) {
1052 klassOop sub = subk->as_klassOop();
1053 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1054 if (is_participant(sub)) {
1055 if (participants_hide_witnesses) continue;
1056 // else fall through to process this guy's subclasses
1057 } else if (is_witness(sub) && !ignore_witness(sub)) {
1058 return sub;
1059 }
1060 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1061 // Fast path. (Partially disabled if VerifyDependencies.)
1062 ADD_SUBCLASS_CHAIN(sub);
1063 } else {
1064 // Worklist overflow. Do a recursive call. Should be rare.
1065 // The recursive call will have its own worklist, of course.
1066 // (Note that sub has already been tested, so that there is
1067 // no need for the recursive call to re-test. That's handy,
1068 // since the recursive call sees sub as the context_type.)
1069 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1070 klassOop witness = find_witness_anywhere(sub,
1071 participants_hide_witnesses,
1072 /*top_level_call=*/ false);
1073 if (witness != NULL) return witness;
1074 }
1075 }
1076 }
1077
1078 // No witness found. The dependency remains unbroken.
1079 return NULL;
1080 #undef ADD_SUBCLASS_CHAIN
1081 }
1082
1083
1084 bool Dependencies::is_concrete_klass(klassOop k) {
1085 if (Klass::cast(k)->is_abstract()) return false;
1086 // %%% We could treat classes which are concrete but
1087 // have not yet been instantiated as virtually abstract.
1088 // This would require a deoptimization barrier on first instantiation.
1089 //if (k->is_not_instantiated()) return false;
1090 return true;
1091 }
1092
1093 bool Dependencies::is_concrete_method(methodOop m) {
1094 if (m->is_abstract()) return false;
1095 // %%% We could treat unexecuted methods as virtually abstract also.
1096 // This would require a deoptimization barrier on first execution.
1097 return !m->is_abstract();
1098 }
1099
1100
1101 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1102 if (k->is_interface()) return NULL;
1103 if (k->has_finalizer()) return k;
1104 k = k->subklass();
1105 while (k != NULL) {
1106 Klass* result = find_finalizable_subclass(k);
1107 if (result != NULL) return result;
1108 k = k->next_sibling();
1109 }
1110 return NULL;
1111 }
1112
1113
1114 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1115 if (k->is_abstract()) return false;
1116 // We could return also false if k does not yet appear to be
1117 // instantiated, if the VM version supports this distinction also.
1118 //if (k->is_not_instantiated()) return false;
1119 return true;
1120 }
1121
1122 bool Dependencies::is_concrete_method(ciMethod* m) {
1123 // Statics are irrelevant to virtual call sites.
1124 if (m->is_static()) return false;
1125
1126 // We could return also false if m does not yet appear to be
1127 // executed, if the VM version supports this distinction also.
1128 return !m->is_abstract();
1129 }
1130
1131
1132 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1133 return k->has_finalizable_subclass();
1134 }
1135
1136
1137 // Any use of the contents (bytecodes) of a method must be
1138 // marked by an "evol_method" dependency, if those contents
1139 // can change. (Note: A method is always dependent on itself.)
1140 klassOop Dependencies::check_evol_method(methodOop m) {
1141 assert(must_be_in_vm(), "raw oops here");
1142 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1143 // Or is there a now a breakpoint?
1144 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1145 if (m->is_old()
1146 || m->number_of_breakpoints() > 0) {
1147 return m->method_holder();
1148 } else {
1149 return NULL;
1150 }
1151 }
1152
1153 // This is a strong assertion: It is that the given type
1154 // has no subtypes whatever. It is most useful for
1155 // optimizing checks on reflected types or on array types.
1156 // (Checks on types which are derived from real instances
1157 // can be optimized more strongly than this, because we
1158 // know that the checked type comes from a concrete type,
1159 // and therefore we can disregard abstract types.)
1160 klassOop Dependencies::check_leaf_type(klassOop ctxk) {
1161 assert(must_be_in_vm(), "raw oops here");
1162 assert_locked_or_safepoint(Compile_lock);
1163 instanceKlass* ctx = instanceKlass::cast(ctxk);
1164 Klass* sub = ctx->subklass();
1165 if (sub != NULL) {
1166 return sub->as_klassOop();
1167 } else if (ctx->nof_implementors() != 0) {
1168 // if it is an interface, it must be unimplemented
1169 // (if it is not an interface, nof_implementors is always zero)
1170 klassOop impl = ctx->implementor(0);
1171 return (impl != NULL)? impl: ctxk;
1172 } else {
1173 return NULL;
1174 }
1175 }
1176
1177 // Test the assertion that conck is the only concrete subtype* of ctxk.
1178 // The type conck itself is allowed to have have further concrete subtypes.
1179 // This allows the compiler to narrow occurrences of ctxk by conck,
1180 // when dealing with the types of actual instances.
1181 klassOop Dependencies::check_abstract_with_unique_concrete_subtype(klassOop ctxk,
1182 klassOop conck,
1183 KlassDepChange* changes) {
1184 ClassHierarchyWalker wf(conck);
1185 return wf.find_witness_subtype(ctxk, changes);
1186 }
1187
1188 // If a non-concrete class has no concrete subtypes, it is not (yet)
1189 // instantiatable. This can allow the compiler to make some paths go
1190 // dead, if they are gated by a test of the type.
1191 klassOop Dependencies::check_abstract_with_no_concrete_subtype(klassOop ctxk,
1192 KlassDepChange* changes) {
1193 // Find any concrete subtype, with no participants:
1194 ClassHierarchyWalker wf;
1195 return wf.find_witness_subtype(ctxk, changes);
1196 }
1197
1198
1199 // If a concrete class has no concrete subtypes, it can always be
1200 // exactly typed. This allows the use of a cheaper type test.
1201 klassOop Dependencies::check_concrete_with_no_concrete_subtype(klassOop ctxk,
1202 KlassDepChange* changes) {
1203 // Find any concrete subtype, with only the ctxk as participant:
1204 ClassHierarchyWalker wf(ctxk);
1205 return wf.find_witness_subtype(ctxk, changes);
1206 }
1207
1208
1209 // Find the unique concrete proper subtype of ctxk, or NULL if there
1210 // is more than one concrete proper subtype. If there are no concrete
1211 // proper subtypes, return ctxk itself, whether it is concrete or not.
1212 // The returned subtype is allowed to have have further concrete subtypes.
1213 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1214 klassOop Dependencies::find_unique_concrete_subtype(klassOop ctxk) {
1215 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1216 wf.record_witnesses(1); // Record one other witness when walking.
1217 klassOop wit = wf.find_witness_subtype(ctxk);
1218 if (wit != NULL) return NULL; // Too many witnesses.
1219 klassOop conck = wf.participant(0);
1220 if (conck == NULL) {
1221 #ifndef PRODUCT
1222 // Make sure the dependency mechanism will pass this discovery:
1223 if (VerifyDependencies) {
1224 // Turn off dependency tracing while actually testing deps.
1225 FlagSetting fs(TraceDependencies, false);
1226 if (!Dependencies::is_concrete_klass(ctxk)) {
1227 guarantee(NULL ==
1228 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1229 "verify dep.");
1230 } else {
1231 guarantee(NULL ==
1232 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1233 "verify dep.");
1234 }
1235 }
1236 #endif //PRODUCT
1237 return ctxk; // Return ctxk as a flag for "no subtypes".
1238 } else {
1239 #ifndef PRODUCT
1240 // Make sure the dependency mechanism will pass this discovery:
1241 if (VerifyDependencies) {
1242 // Turn off dependency tracing while actually testing deps.
1243 FlagSetting fs(TraceDependencies, false);
1244 if (!Dependencies::is_concrete_klass(ctxk)) {
1245 guarantee(NULL == (void *)
1246 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1247 "verify dep.");
1248 }
1249 }
1250 #endif //PRODUCT
1251 return conck;
1252 }
1253 }
1254
1255 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1256 // except possibly for further subtypes of k[12] themselves.
1257 // The context type must be abstract. The types k1 and k2 are themselves
1258 // allowed to have further concrete subtypes.
1259 klassOop Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1260 klassOop ctxk,
1261 klassOop k1,
1262 klassOop k2,
1263 KlassDepChange* changes) {
1264 ClassHierarchyWalker wf;
1265 wf.add_participant(k1);
1266 wf.add_participant(k2);
1267 return wf.find_witness_subtype(ctxk, changes);
1268 }
1269
1270 // Search ctxk for concrete implementations. If there are klen or fewer,
1271 // pack them into the given array and return the number.
1272 // Otherwise, return -1, meaning the given array would overflow.
1273 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1274 // In this search, if ctxk is concrete, it will be reported alone.
1275 // For any type CC reported, no proper subtypes of CC will be reported.
1276 int Dependencies::find_exclusive_concrete_subtypes(klassOop ctxk,
1277 int klen,
1278 klassOop karray[]) {
1279 ClassHierarchyWalker wf;
1280 wf.record_witnesses(klen);
1281 klassOop wit = wf.find_witness_subtype(ctxk);
1282 if (wit != NULL) return -1; // Too many witnesses.
1283 int num = wf.num_participants();
1284 assert(num <= klen, "oob");
1285 // Pack the result array with the good news.
1286 for (int i = 0; i < num; i++)
1287 karray[i] = wf.participant(i);
1288 #ifndef PRODUCT
1289 // Make sure the dependency mechanism will pass this discovery:
1290 if (VerifyDependencies) {
1291 // Turn off dependency tracing while actually testing deps.
1292 FlagSetting fs(TraceDependencies, false);
1293 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1294 case -1: // ctxk was itself concrete
1295 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1296 break;
1297 case 0:
1298 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1299 "verify dep.");
1300 break;
1301 case 1:
1302 guarantee(NULL == (void *)
1303 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1304 "verify dep.");
1305 break;
1306 case 2:
1307 guarantee(NULL == (void *)
1308 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1309 karray[0],
1310 karray[1]),
1311 "verify dep.");
1312 break;
1313 default:
1314 ShouldNotReachHere(); // klen > 2 yet supported
1315 }
1316 }
1317 #endif //PRODUCT
1318 return num;
1319 }
1320
1321 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1322 // Otherwise, return a class that contains an interfering method.
1323 klassOop Dependencies::check_unique_concrete_method(klassOop ctxk, methodOop uniqm,
1324 KlassDepChange* changes) {
1325 // Here is a missing optimization: If uniqm->is_final(),
1326 // we don't really need to search beneath it for overrides.
1327 // This is probably not important, since we don't use dependencies
1328 // to track final methods. (They can't be "definalized".)
1329 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1330 return wf.find_witness_definer(ctxk, changes);
1331 }
1332
1333 // Find the set of all non-abstract methods under ctxk that match m.
1334 // (The method m must be defined or inherited in ctxk.)
1335 // Include m itself in the set, unless it is abstract.
1336 // If this set has exactly one element, return that element.
1337 methodOop Dependencies::find_unique_concrete_method(klassOop ctxk, methodOop m) {
1338 ClassHierarchyWalker wf(m);
1339 assert(wf.check_method_context(ctxk, m), "proper context");
1340 wf.record_witnesses(1);
1341 klassOop wit = wf.find_witness_definer(ctxk);
1342 if (wit != NULL) return NULL; // Too many witnesses.
1343 methodOop fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1344 if (Dependencies::is_concrete_method(m)) {
1345 if (fm == NULL) {
1346 // It turns out that m was always the only implementation.
1347 fm = m;
1348 } else if (fm != m) {
1349 // Two conflicting implementations after all.
1350 // (This can happen if m is inherited into ctxk and fm overrides it.)
1351 return NULL;
1352 }
1353 }
1354 #ifndef PRODUCT
1355 // Make sure the dependency mechanism will pass this discovery:
1356 if (VerifyDependencies && fm != NULL) {
1357 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1358 "verify dep.");
1359 }
1360 #endif //PRODUCT
1361 return fm;
1362 }
1363
1364 klassOop Dependencies::check_exclusive_concrete_methods(klassOop ctxk,
1365 methodOop m1,
1366 methodOop m2,
1367 KlassDepChange* changes) {
1368 ClassHierarchyWalker wf(m1);
1369 wf.add_participant(m1->method_holder());
1370 wf.add_participant(m2->method_holder());
1371 return wf.find_witness_definer(ctxk, changes);
1372 }
1373
1374 // Find the set of all non-abstract methods under ctxk that match m[0].
1375 // (The method m[0] must be defined or inherited in ctxk.)
1376 // Include m itself in the set, unless it is abstract.
1377 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1378 // (The length may be zero if no concrete methods are found anywhere.)
1379 // If there are too many concrete methods to fit in marray, return -1.
1380 int Dependencies::find_exclusive_concrete_methods(klassOop ctxk,
1381 int mlen,
1382 methodOop marray[]) {
1383 methodOop m0 = marray[0];
1384 ClassHierarchyWalker wf(m0);
1385 assert(wf.check_method_context(ctxk, m0), "proper context");
1386 wf.record_witnesses(mlen);
1387 bool participants_hide_witnesses = true;
1388 klassOop wit = wf.find_witness_definer(ctxk);
1389 if (wit != NULL) return -1; // Too many witnesses.
1390 int num = wf.num_participants();
1391 assert(num <= mlen, "oob");
1392 // Keep track of whether m is also part of the result set.
1393 int mfill = 0;
1394 assert(marray[mfill] == m0, "sanity");
1395 if (Dependencies::is_concrete_method(m0))
1396 mfill++; // keep m0 as marray[0], the first result
1397 for (int i = 0; i < num; i++) {
1398 methodOop fm = wf.found_method(i);
1399 if (fm == m0) continue; // Already put this guy in the list.
1400 if (mfill == mlen) {
1401 return -1; // Oops. Too many methods after all!
1402 }
1403 marray[mfill++] = fm;
1404 }
1405 #ifndef PRODUCT
1406 // Make sure the dependency mechanism will pass this discovery:
1407 if (VerifyDependencies) {
1408 // Turn off dependency tracing while actually testing deps.
1409 FlagSetting fs(TraceDependencies, false);
1410 switch (mfill) {
1411 case 1:
1412 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1413 "verify dep.");
1414 break;
1415 case 2:
1416 guarantee(NULL == (void *)
1417 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1418 "verify dep.");
1419 break;
1420 default:
1421 ShouldNotReachHere(); // mlen > 2 yet supported
1422 }
1423 }
1424 #endif //PRODUCT
1425 return mfill;
1426 }
1427
1428
1429 klassOop Dependencies::check_has_no_finalizable_subclasses(klassOop ctxk, KlassDepChange* changes) {
1430 Klass* search_at = ctxk->klass_part();
1431 if (changes != NULL)
1432 search_at = changes->new_type()->klass_part(); // just look at the new bit
1433 Klass* result = find_finalizable_subclass(search_at);
1434 if (result == NULL) {
1435 return NULL;
1436 }
1437 return result->as_klassOop();
1438 }
1439
1440
1441 klassOop Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1442 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1443 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1444 if (changes == NULL) {
1445 // Validate all CallSites
1446 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1447 return call_site->klass(); // assertion failed
1448 } else {
1449 // Validate the given CallSite
1450 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1451 assert(method_handle != changes->method_handle(), "must be");
1452 return call_site->klass(); // assertion failed
1453 }
1454 }
1455 return NULL; // assertion still valid
1456 }
1457
1458
1459 void Dependencies::DepStream::trace_and_log_witness(klassOop witness) {
1460 if (witness != NULL) {
1461 if (TraceDependencies) {
1462 print_dependency(witness, /*verbose=*/ true);
1463 }
1464 // The following is a no-op unless logging is enabled:
1465 log_dependency(witness);
1466 }
1467 }
1468
1469
1470 klassOop Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1471 assert_locked_or_safepoint(Compile_lock);
1472 Dependencies::check_valid_dependency_type(type());
1473
1474 klassOop witness = NULL;
1475 switch (type()) {
1476 case evol_method:
1477 witness = check_evol_method(method_argument(0));
1478 break;
1479 case leaf_type:
1480 witness = check_leaf_type(context_type());
1481 break;
1482 case abstract_with_unique_concrete_subtype:
1483 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1484 break;
1485 case abstract_with_no_concrete_subtype:
1486 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1487 break;
1488 case concrete_with_no_concrete_subtype:
1489 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1490 break;
1491 case unique_concrete_method:
1492 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1493 break;
1494 case abstract_with_exclusive_concrete_subtypes_2:
1495 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1496 break;
1497 case exclusive_concrete_methods_2:
1498 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1499 break;
1500 case no_finalizable_subclasses:
1501 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1502 break;
1503 default:
1504 witness = NULL;
1505 break;
1506 }
1507 trace_and_log_witness(witness);
1508 return witness;
1509 }
1510
1511
1512 klassOop Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1513 assert_locked_or_safepoint(Compile_lock);
1514 Dependencies::check_valid_dependency_type(type());
1515
1516 klassOop witness = NULL;
1517 switch (type()) {
1518 case call_site_target_value:
1519 witness = check_call_site_target_value(argument(0), argument(1), changes);
1520 break;
1521 default:
1522 witness = NULL;
1523 break;
1524 }
1525 trace_and_log_witness(witness);
1526 return witness;
1527 }
1528
1529
1530 klassOop Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1531 // Handle klass dependency
1532 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1533 return check_klass_dependency(changes.as_klass_change());
1534
1535 // Handle CallSite dependency
1536 if (changes.is_call_site_change())
1537 return check_call_site_dependency(changes.as_call_site_change());
1538
1539 // irrelevant dependency; skip it
1540 return NULL;
1541 }
1542
1543
1544 void DepChange::print() {
1545 int nsup = 0, nint = 0;
1546 for (ContextStream str(*this); str.next(); ) {
1547 klassOop k = str.klass();
1548 switch (str.change_type()) {
1549 case Change_new_type:
1550 tty->print_cr(" dependee = %s", instanceKlass::cast(k)->external_name());
1551 break;
1552 case Change_new_sub:
1553 if (!WizardMode) {
1554 ++nsup;
1555 } else {
1556 tty->print_cr(" context super = %s", instanceKlass::cast(k)->external_name());
1557 }
1558 break;
1559 case Change_new_impl:
1560 if (!WizardMode) {
1561 ++nint;
1562 } else {
1563 tty->print_cr(" context interface = %s", instanceKlass::cast(k)->external_name());
1564 }
1565 break;
1566 }
1567 }
1568 if (nsup + nint != 0) {
1569 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1570 }
1571 }
1572
1573 void DepChange::ContextStream::start() {
1574 klassOop new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (klassOop) NULL;
1575 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1576 _klass = new_type;
1577 _ti_base = NULL;
1578 _ti_index = 0;
1579 _ti_limit = 0;
1580 }
1581
1582 bool DepChange::ContextStream::next() {
1583 switch (_change_type) {
1584 case Start_Klass: // initial state; _klass is the new type
1585 _ti_base = instanceKlass::cast(_klass)->transitive_interfaces();
1586 _ti_index = 0;
1587 _change_type = Change_new_type;
1588 return true;
1589 case Change_new_type:
1590 // fall through:
1591 _change_type = Change_new_sub;
1592 case Change_new_sub:
1593 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1594 {
1595 _klass = instanceKlass::cast(_klass)->super();
1596 if (_klass != NULL) {
1597 return true;
1598 }
1599 }
1600 // else set up _ti_limit and fall through:
1601 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1602 _change_type = Change_new_impl;
1603 case Change_new_impl:
1604 if (_ti_index < _ti_limit) {
1605 _klass = klassOop( _ti_base->obj_at(_ti_index++) );
1606 return true;
1607 }
1608 // fall through:
1609 _change_type = NO_CHANGE; // iterator is exhausted
1610 case NO_CHANGE:
1611 break;
1612 default:
1613 ShouldNotReachHere();
1614 }
1615 return false;
1616 }
1617
1618 void KlassDepChange::initialize() {
1619 // entire transaction must be under this lock:
1620 assert_lock_strong(Compile_lock);
1621
1622 // Mark all dependee and all its superclasses
1623 // Mark transitive interfaces
1624 for (ContextStream str(*this); str.next(); ) {
1625 klassOop d = str.klass();
1626 assert(!instanceKlass::cast(d)->is_marked_dependent(), "checking");
1627 instanceKlass::cast(d)->set_is_marked_dependent(true);
1628 }
1629 }
1630
1631 KlassDepChange::~KlassDepChange() {
1632 // Unmark all dependee and all its superclasses
1633 // Unmark transitive interfaces
1634 for (ContextStream str(*this); str.next(); ) {
1635 klassOop d = str.klass();
1636 instanceKlass::cast(d)->set_is_marked_dependent(false);
1637 }
1638 }
1639
1640 bool KlassDepChange::involves_context(klassOop k) {
1641 if (k == NULL || !Klass::cast(k)->oop_is_instance()) {
1642 return false;
1643 }
1644 instanceKlass* ik = instanceKlass::cast(k);
1645 bool is_contained = ik->is_marked_dependent();
1646 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k),
1647 "correct marking of potential context types");
1648 return is_contained;
1649 }
1650
1651 #ifndef PRODUCT
1652 void Dependencies::print_statistics() {
1653 if (deps_find_witness_print != 0) {
1654 // Call one final time, to flush out the data.
1655 deps_find_witness_print = -1;
1656 count_find_witness_calls();
1657 }
1658 }
1659 #endif