Tue, 16 Aug 2011 04:14:05 -0700
7071653: JSR 292: call site change notification should be pushed not pulled
Reviewed-by: kvn, never, bdelsart
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 */
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"
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
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;
59 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
60 }
62 void Dependencies::assert_evol_method(ciMethod* m) {
63 assert_common_1(evol_method, m);
64 }
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 }
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 }
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 }
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 }
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 }
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 }
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 }
111 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
112 check_ctxk(ctxk);
113 assert_common_1(no_finalizable_subclasses, ctxk);
114 }
116 void Dependencies::assert_call_site_target_value(ciKlass* ctxk, ciCallSite* call_site, ciMethodHandle* method_handle) {
117 check_ctxk(ctxk);
118 assert_common_3(call_site_target_value, ctxk, call_site, method_handle);
119 }
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 }
138 void Dependencies::assert_common_1(Dependencies::DepType dept, ciObject* x) {
139 assert(dep_args(dept) == 1, "sanity");
140 log_dependency(dept, x);
141 GrowableArray<ciObject*>* deps = _deps[dept];
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 }
151 void Dependencies::assert_common_2(Dependencies::DepType dept,
152 ciKlass* ctxk, ciObject* x) {
153 assert(dep_context_arg(dept) == 0, "sanity");
154 assert(dep_args(dept) == 2, "sanity");
155 log_dependency(dept, ctxk, x);
156 GrowableArray<ciObject*>* deps = _deps[dept];
158 // see if the same (or a similar) dep is already recorded
159 if (note_dep_seen(dept, x)) {
160 // look in this bucket for redundant assertions
161 const int stride = 2;
162 for (int i = deps->length(); (i -= stride) >= 0; ) {
163 ciObject* x1 = deps->at(i+1);
164 if (x == x1) { // same subject; check the context
165 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
166 return;
167 }
168 }
169 }
170 }
172 // append the assertion in the correct bucket:
173 deps->append(ctxk);
174 deps->append(x);
175 }
177 void Dependencies::assert_common_3(Dependencies::DepType dept,
178 ciKlass* ctxk, ciObject* x, ciObject* x2) {
179 assert(dep_context_arg(dept) == 0, "sanity");
180 assert(dep_args(dept) == 3, "sanity");
181 log_dependency(dept, ctxk, x, x2);
182 GrowableArray<ciObject*>* deps = _deps[dept];
184 // try to normalize an unordered pair:
185 bool swap = false;
186 switch (dept) {
187 case abstract_with_exclusive_concrete_subtypes_2:
188 swap = (x->ident() > x2->ident() && x != ctxk);
189 break;
190 case exclusive_concrete_methods_2:
191 swap = (x->ident() > x2->ident() && x->as_method()->holder() != ctxk);
192 break;
193 }
194 if (swap) { ciObject* t = x; x = x2; x2 = t; }
196 // see if the same (or a similar) dep is already recorded
197 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
198 // look in this bucket for redundant assertions
199 const int stride = 3;
200 for (int i = deps->length(); (i -= stride) >= 0; ) {
201 ciObject* y = deps->at(i+1);
202 ciObject* y2 = deps->at(i+2);
203 if (x == y && x2 == y2) { // same subjects; check the context
204 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
205 return;
206 }
207 }
208 }
209 }
210 // append the assertion in the correct bucket:
211 deps->append(ctxk);
212 deps->append(x);
213 deps->append(x2);
214 }
216 /// Support for encoding dependencies into an nmethod:
218 void Dependencies::copy_to(nmethod* nm) {
219 address beg = nm->dependencies_begin();
220 address end = nm->dependencies_end();
221 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
222 Copy::disjoint_words((HeapWord*) content_bytes(),
223 (HeapWord*) beg,
224 size_in_bytes() / sizeof(HeapWord));
225 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
226 }
228 static int sort_dep(ciObject** p1, ciObject** p2, int narg) {
229 for (int i = 0; i < narg; i++) {
230 int diff = p1[i]->ident() - p2[i]->ident();
231 if (diff != 0) return diff;
232 }
233 return 0;
234 }
235 static int sort_dep_arg_1(ciObject** p1, ciObject** p2)
236 { return sort_dep(p1, p2, 1); }
237 static int sort_dep_arg_2(ciObject** p1, ciObject** p2)
238 { return sort_dep(p1, p2, 2); }
239 static int sort_dep_arg_3(ciObject** p1, ciObject** p2)
240 { return sort_dep(p1, p2, 3); }
242 void Dependencies::sort_all_deps() {
243 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
244 DepType dept = (DepType)deptv;
245 GrowableArray<ciObject*>* deps = _deps[dept];
246 if (deps->length() <= 1) continue;
247 switch (dep_args(dept)) {
248 case 1: deps->sort(sort_dep_arg_1, 1); break;
249 case 2: deps->sort(sort_dep_arg_2, 2); break;
250 case 3: deps->sort(sort_dep_arg_3, 3); break;
251 default: ShouldNotReachHere();
252 }
253 }
254 }
256 size_t Dependencies::estimate_size_in_bytes() {
257 size_t est_size = 100;
258 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
259 DepType dept = (DepType)deptv;
260 GrowableArray<ciObject*>* deps = _deps[dept];
261 est_size += deps->length()*2; // tags and argument(s)
262 }
263 return est_size;
264 }
266 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciObject* x) {
267 switch (dept) {
268 case abstract_with_exclusive_concrete_subtypes_2:
269 return x->as_klass();
270 case unique_concrete_method:
271 case exclusive_concrete_methods_2:
272 return x->as_method()->holder();
273 }
274 return NULL; // let NULL be NULL
275 }
277 klassOop Dependencies::ctxk_encoded_as_null(DepType dept, oop x) {
278 assert(must_be_in_vm(), "raw oops here");
279 switch (dept) {
280 case abstract_with_exclusive_concrete_subtypes_2:
281 assert(x->is_klass(), "sanity");
282 return (klassOop) x;
283 case unique_concrete_method:
284 case exclusive_concrete_methods_2:
285 assert(x->is_method(), "sanity");
286 return ((methodOop)x)->method_holder();
287 }
288 return NULL; // let NULL be NULL
289 }
291 void Dependencies::encode_content_bytes() {
292 sort_all_deps();
294 // cast is safe, no deps can overflow INT_MAX
295 CompressedWriteStream bytes((int)estimate_size_in_bytes());
297 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
298 DepType dept = (DepType)deptv;
299 GrowableArray<ciObject*>* deps = _deps[dept];
300 if (deps->length() == 0) continue;
301 int stride = dep_args(dept);
302 int ctxkj = dep_context_arg(dept); // -1 if no context arg
303 assert(stride > 0, "sanity");
304 for (int i = 0; i < deps->length(); i += stride) {
305 jbyte code_byte = (jbyte)dept;
306 int skipj = -1;
307 if (ctxkj >= 0 && ctxkj+1 < stride) {
308 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_klass();
309 ciObject* x = deps->at(i+ctxkj+1); // following argument
310 if (ctxk == ctxk_encoded_as_null(dept, x)) {
311 skipj = ctxkj; // we win: maybe one less oop to keep track of
312 code_byte |= default_context_type_bit;
313 }
314 }
315 bytes.write_byte(code_byte);
316 for (int j = 0; j < stride; j++) {
317 if (j == skipj) continue;
318 bytes.write_int(_oop_recorder->find_index(deps->at(i+j)->constant_encoding()));
319 }
320 }
321 }
323 // write a sentinel byte to mark the end
324 bytes.write_byte(end_marker);
326 // round it out to a word boundary
327 while (bytes.position() % sizeof(HeapWord) != 0) {
328 bytes.write_byte(end_marker);
329 }
331 // check whether the dept byte encoding really works
332 assert((jbyte)default_context_type_bit != 0, "byte overflow");
334 _content_bytes = bytes.buffer();
335 _size_in_bytes = bytes.position();
336 }
339 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
340 "end_marker",
341 "evol_method",
342 "leaf_type",
343 "abstract_with_unique_concrete_subtype",
344 "abstract_with_no_concrete_subtype",
345 "concrete_with_no_concrete_subtype",
346 "unique_concrete_method",
347 "abstract_with_exclusive_concrete_subtypes_2",
348 "exclusive_concrete_methods_2",
349 "no_finalizable_subclasses",
350 "call_site_target_value"
351 };
353 int Dependencies::_dep_args[TYPE_LIMIT] = {
354 -1,// end_marker
355 1, // evol_method m
356 1, // leaf_type ctxk
357 2, // abstract_with_unique_concrete_subtype ctxk, k
358 1, // abstract_with_no_concrete_subtype ctxk
359 1, // concrete_with_no_concrete_subtype ctxk
360 2, // unique_concrete_method ctxk, m
361 3, // unique_concrete_subtypes_2 ctxk, k1, k2
362 3, // unique_concrete_methods_2 ctxk, m1, m2
363 1, // no_finalizable_subclasses ctxk
364 3 // call_site_target_value ctxk, call_site, method_handle
365 };
367 const char* Dependencies::dep_name(Dependencies::DepType dept) {
368 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
369 return _dep_name[dept];
370 }
372 int Dependencies::dep_args(Dependencies::DepType dept) {
373 if (!dept_in_mask(dept, all_types)) return -1;
374 return _dep_args[dept];
375 }
377 void Dependencies::check_valid_dependency_type(DepType dept) {
378 for (int deptv = (int) FIRST_TYPE; deptv < (int) TYPE_LIMIT; deptv++) {
379 if (dept == ((DepType) deptv)) return;
380 }
381 ShouldNotReachHere();
382 }
384 // for the sake of the compiler log, print out current dependencies:
385 void Dependencies::log_all_dependencies() {
386 if (log() == NULL) return;
387 ciObject* args[max_arg_count];
388 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
389 DepType dept = (DepType)deptv;
390 GrowableArray<ciObject*>* deps = _deps[dept];
391 if (deps->length() == 0) continue;
392 int stride = dep_args(dept);
393 for (int i = 0; i < deps->length(); i += stride) {
394 for (int j = 0; j < stride; j++) {
395 // flush out the identities before printing
396 args[j] = deps->at(i+j);
397 }
398 write_dependency_to(log(), dept, stride, args);
399 }
400 }
401 }
403 void Dependencies::write_dependency_to(CompileLog* log,
404 DepType dept,
405 int nargs, oop args[],
406 klassOop witness) {
407 if (log == NULL) {
408 return;
409 }
410 ciEnv* env = ciEnv::current();
411 ciObject* ciargs[max_arg_count];
412 assert(nargs <= max_arg_count, "oob");
413 for (int j = 0; j < nargs; j++) {
414 ciargs[j] = env->get_object(args[j]);
415 }
416 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
417 }
419 void Dependencies::write_dependency_to(CompileLog* log,
420 DepType dept,
421 int nargs, ciObject* args[],
422 klassOop witness) {
423 if (log == NULL) return;
424 assert(nargs <= max_arg_count, "oob");
425 int argids[max_arg_count];
426 int ctxkj = dep_context_arg(dept); // -1 if no context arg
427 int j;
428 for (j = 0; j < nargs; j++) {
429 argids[j] = log->identify(args[j]);
430 }
431 if (witness != NULL) {
432 log->begin_elem("dependency_failed");
433 } else {
434 log->begin_elem("dependency");
435 }
436 log->print(" type='%s'", dep_name(dept));
437 if (ctxkj >= 0) {
438 log->print(" ctxk='%d'", argids[ctxkj]);
439 }
440 // write remaining arguments, if any.
441 for (j = 0; j < nargs; j++) {
442 if (j == ctxkj) continue; // already logged
443 if (j == 1) {
444 log->print( " x='%d'", argids[j]);
445 } else {
446 log->print(" x%d='%d'", j, argids[j]);
447 }
448 }
449 if (witness != NULL) {
450 log->object("witness", witness);
451 log->stamp();
452 }
453 log->end_elem();
454 }
456 void Dependencies::write_dependency_to(xmlStream* xtty,
457 DepType dept,
458 int nargs, oop args[],
459 klassOop witness) {
460 if (xtty == NULL) return;
461 ttyLocker ttyl;
462 int ctxkj = dep_context_arg(dept); // -1 if no context arg
463 if (witness != NULL) {
464 xtty->begin_elem("dependency_failed");
465 } else {
466 xtty->begin_elem("dependency");
467 }
468 xtty->print(" type='%s'", dep_name(dept));
469 if (ctxkj >= 0) {
470 xtty->object("ctxk", args[ctxkj]);
471 }
472 // write remaining arguments, if any.
473 for (int j = 0; j < nargs; j++) {
474 if (j == ctxkj) continue; // already logged
475 if (j == 1) {
476 xtty->object("x", args[j]);
477 } else {
478 char xn[10]; sprintf(xn, "x%d", j);
479 xtty->object(xn, args[j]);
480 }
481 }
482 if (witness != NULL) {
483 xtty->object("witness", witness);
484 xtty->stamp();
485 }
486 xtty->end_elem();
487 }
489 void Dependencies::print_dependency(DepType dept, int nargs, oop args[],
490 klassOop witness) {
491 ResourceMark rm;
492 ttyLocker ttyl; // keep the following output all in one block
493 tty->print_cr("%s of type %s",
494 (witness == NULL)? "Dependency": "Failed dependency",
495 dep_name(dept));
496 // print arguments
497 int ctxkj = dep_context_arg(dept); // -1 if no context arg
498 for (int j = 0; j < nargs; j++) {
499 oop arg = args[j];
500 bool put_star = false;
501 if (arg == NULL) continue;
502 const char* what;
503 if (j == ctxkj) {
504 what = "context";
505 put_star = !Dependencies::is_concrete_klass((klassOop)arg);
506 } else if (arg->is_method()) {
507 what = "method ";
508 put_star = !Dependencies::is_concrete_method((methodOop)arg);
509 } else if (arg->is_klass()) {
510 what = "class ";
511 } else {
512 what = "object ";
513 }
514 tty->print(" %s = %s", what, (put_star? "*": ""));
515 if (arg->is_klass())
516 tty->print("%s", Klass::cast((klassOop)arg)->external_name());
517 else
518 arg->print_value();
519 tty->cr();
520 }
521 if (witness != NULL) {
522 bool put_star = !Dependencies::is_concrete_klass(witness);
523 tty->print_cr(" witness = %s%s",
524 (put_star? "*": ""),
525 Klass::cast(witness)->external_name());
526 }
527 }
529 void Dependencies::DepStream::log_dependency(klassOop witness) {
530 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
531 int nargs = argument_count();
532 oop args[max_arg_count];
533 for (int j = 0; j < nargs; j++) {
534 args[j] = argument(j);
535 }
536 if (_deps != NULL && _deps->log() != NULL) {
537 Dependencies::write_dependency_to(_deps->log(),
538 type(), nargs, args, witness);
539 } else {
540 Dependencies::write_dependency_to(xtty,
541 type(), nargs, args, witness);
542 }
543 }
545 void Dependencies::DepStream::print_dependency(klassOop witness, bool verbose) {
546 int nargs = argument_count();
547 oop args[max_arg_count];
548 for (int j = 0; j < nargs; j++) {
549 args[j] = argument(j);
550 }
551 Dependencies::print_dependency(type(), nargs, args, witness);
552 if (verbose) {
553 if (_code != NULL) {
554 tty->print(" code: ");
555 _code->print_value_on(tty);
556 tty->cr();
557 }
558 }
559 }
562 /// Dependency stream support (decodes dependencies from an nmethod):
564 #ifdef ASSERT
565 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
566 assert(must_be_in_vm(), "raw oops here");
567 _byte_limit = byte_limit;
568 _type = (DepType)(end_marker-1); // defeat "already at end" assert
569 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
570 }
571 #endif //ASSERT
573 bool Dependencies::DepStream::next() {
574 assert(_type != end_marker, "already at end");
575 if (_bytes.position() == 0 && _code != NULL
576 && _code->dependencies_size() == 0) {
577 // Method has no dependencies at all.
578 return false;
579 }
580 int code_byte = (_bytes.read_byte() & 0xFF);
581 if (code_byte == end_marker) {
582 DEBUG_ONLY(_type = end_marker);
583 return false;
584 } else {
585 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
586 code_byte -= ctxk_bit;
587 DepType dept = (DepType)code_byte;
588 _type = dept;
589 guarantee((dept - FIRST_TYPE) < (TYPE_LIMIT - FIRST_TYPE),
590 "bad dependency type tag");
591 int stride = _dep_args[dept];
592 assert(stride == dep_args(dept), "sanity");
593 int skipj = -1;
594 if (ctxk_bit != 0) {
595 skipj = 0; // currently the only context argument is at zero
596 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
597 }
598 for (int j = 0; j < stride; j++) {
599 _xi[j] = (j == skipj)? 0: _bytes.read_int();
600 }
601 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
602 return true;
603 }
604 }
606 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
607 return (_code != NULL)
608 ? _code->oop_at(i)
609 : JNIHandles::resolve(_deps->oop_recorder()->handle_at(i));
610 }
612 oop Dependencies::DepStream::argument(int i) {
613 return recorded_oop_at(argument_index(i));
614 }
616 klassOop Dependencies::DepStream::context_type() {
617 assert(must_be_in_vm(), "raw oops here");
618 int ctxkj = dep_context_arg(_type); // -1 if no context arg
619 if (ctxkj < 0) {
620 return NULL; // for example, evol_method
621 } else {
622 oop k = recorded_oop_at(_xi[ctxkj]);
623 if (k != NULL) { // context type was not compressed away
624 assert(k->is_klass(), "type check");
625 return (klassOop) k;
626 } else { // recompute "default" context type
627 return ctxk_encoded_as_null(_type, recorded_oop_at(_xi[ctxkj+1]));
628 }
629 }
630 }
632 /// Checking dependencies:
634 // This hierarchy walker inspects subtypes of a given type,
635 // trying to find a "bad" class which breaks a dependency.
636 // Such a class is called a "witness" to the broken dependency.
637 // While searching around, we ignore "participants", which
638 // are already known to the dependency.
639 class ClassHierarchyWalker {
640 public:
641 enum { PARTICIPANT_LIMIT = 3 };
643 private:
644 // optional method descriptor to check for:
645 Symbol* _name;
646 Symbol* _signature;
648 // special classes which are not allowed to be witnesses:
649 klassOop _participants[PARTICIPANT_LIMIT+1];
650 int _num_participants;
652 // cache of method lookups
653 methodOop _found_methods[PARTICIPANT_LIMIT+1];
655 // if non-zero, tells how many witnesses to convert to participants
656 int _record_witnesses;
658 void initialize(klassOop participant) {
659 _record_witnesses = 0;
660 _participants[0] = participant;
661 _found_methods[0] = NULL;
662 _num_participants = 0;
663 if (participant != NULL) {
664 // Terminating NULL.
665 _participants[1] = NULL;
666 _found_methods[1] = NULL;
667 _num_participants = 1;
668 }
669 }
671 void initialize_from_method(methodOop m) {
672 assert(m != NULL && m->is_method(), "sanity");
673 _name = m->name();
674 _signature = m->signature();
675 }
677 public:
678 // The walker is initialized to recognize certain methods and/or types
679 // as friendly participants.
680 ClassHierarchyWalker(klassOop participant, methodOop m) {
681 initialize_from_method(m);
682 initialize(participant);
683 }
684 ClassHierarchyWalker(methodOop m) {
685 initialize_from_method(m);
686 initialize(NULL);
687 }
688 ClassHierarchyWalker(klassOop participant = NULL) {
689 _name = NULL;
690 _signature = NULL;
691 initialize(participant);
692 }
694 // This is common code for two searches: One for concrete subtypes,
695 // the other for concrete method implementations and overrides.
696 bool doing_subtype_search() {
697 return _name == NULL;
698 }
700 int num_participants() { return _num_participants; }
701 klassOop participant(int n) {
702 assert((uint)n <= (uint)_num_participants, "oob");
703 return _participants[n];
704 }
706 // Note: If n==num_participants, returns NULL.
707 methodOop found_method(int n) {
708 assert((uint)n <= (uint)_num_participants, "oob");
709 methodOop fm = _found_methods[n];
710 assert(n == _num_participants || fm != NULL, "proper usage");
711 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
712 return fm;
713 }
715 #ifdef ASSERT
716 // Assert that m is inherited into ctxk, without intervening overrides.
717 // (May return true even if this is not true, in corner cases where we punt.)
718 bool check_method_context(klassOop ctxk, methodOop m) {
719 if (m->method_holder() == ctxk)
720 return true; // Quick win.
721 if (m->is_private())
722 return false; // Quick lose. Should not happen.
723 if (!(m->is_public() || m->is_protected()))
724 // The override story is complex when packages get involved.
725 return true; // Must punt the assertion to true.
726 Klass* k = Klass::cast(ctxk);
727 methodOop lm = k->lookup_method(m->name(), m->signature());
728 if (lm == NULL && k->oop_is_instance()) {
729 // It might be an abstract interface method, devoid of mirandas.
730 lm = ((instanceKlass*)k)->lookup_method_in_all_interfaces(m->name(),
731 m->signature());
732 }
733 if (lm == m)
734 // Method m is inherited into ctxk.
735 return true;
736 if (lm != NULL) {
737 if (!(lm->is_public() || lm->is_protected()))
738 // Method is [package-]private, so the override story is complex.
739 return true; // Must punt the assertion to true.
740 if ( !Dependencies::is_concrete_method(lm)
741 && !Dependencies::is_concrete_method(m)
742 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder()))
743 // Method m is overridden by lm, but both are non-concrete.
744 return true;
745 }
746 ResourceMark rm;
747 tty->print_cr("Dependency method not found in the associated context:");
748 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name());
749 tty->print( " method = "); m->print_short_name(tty); tty->cr();
750 if (lm != NULL) {
751 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
752 }
753 return false;
754 }
755 #endif
757 void add_participant(klassOop participant) {
758 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
759 int np = _num_participants++;
760 _participants[np] = participant;
761 _participants[np+1] = NULL;
762 _found_methods[np+1] = NULL;
763 }
765 void record_witnesses(int add) {
766 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
767 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
768 _record_witnesses = add;
769 }
771 bool is_witness(klassOop k) {
772 if (doing_subtype_search()) {
773 return Dependencies::is_concrete_klass(k);
774 } else {
775 methodOop m = instanceKlass::cast(k)->find_method(_name, _signature);
776 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
777 _found_methods[_num_participants] = m;
778 // Note: If add_participant(k) is called,
779 // the method m will already be memoized for it.
780 return true;
781 }
782 }
784 bool is_participant(klassOop k) {
785 if (k == _participants[0]) {
786 return true;
787 } else if (_num_participants <= 1) {
788 return false;
789 } else {
790 return in_list(k, &_participants[1]);
791 }
792 }
793 bool ignore_witness(klassOop witness) {
794 if (_record_witnesses == 0) {
795 return false;
796 } else {
797 --_record_witnesses;
798 add_participant(witness);
799 return true;
800 }
801 }
802 static bool in_list(klassOop x, klassOop* list) {
803 for (int i = 0; ; i++) {
804 klassOop y = list[i];
805 if (y == NULL) break;
806 if (y == x) return true;
807 }
808 return false; // not in list
809 }
811 private:
812 // the actual search method:
813 klassOop find_witness_anywhere(klassOop context_type,
814 bool participants_hide_witnesses,
815 bool top_level_call = true);
816 // the spot-checking version:
817 klassOop find_witness_in(KlassDepChange& changes,
818 klassOop context_type,
819 bool participants_hide_witnesses);
820 public:
821 klassOop find_witness_subtype(klassOop context_type, KlassDepChange* changes = NULL) {
822 assert(doing_subtype_search(), "must set up a subtype search");
823 // When looking for unexpected concrete types,
824 // do not look beneath expected ones.
825 const bool participants_hide_witnesses = true;
826 // CX > CC > C' is OK, even if C' is new.
827 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
828 if (changes != NULL) {
829 return find_witness_in(*changes, context_type, participants_hide_witnesses);
830 } else {
831 return find_witness_anywhere(context_type, participants_hide_witnesses);
832 }
833 }
834 klassOop find_witness_definer(klassOop context_type, KlassDepChange* changes = NULL) {
835 assert(!doing_subtype_search(), "must set up a method definer search");
836 // When looking for unexpected concrete methods,
837 // look beneath expected ones, to see if there are overrides.
838 const bool participants_hide_witnesses = true;
839 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
840 if (changes != NULL) {
841 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
842 } else {
843 return find_witness_anywhere(context_type, !participants_hide_witnesses);
844 }
845 }
846 };
848 #ifndef PRODUCT
849 static int deps_find_witness_calls = 0;
850 static int deps_find_witness_steps = 0;
851 static int deps_find_witness_recursions = 0;
852 static int deps_find_witness_singles = 0;
853 static int deps_find_witness_print = 0; // set to -1 to force a final print
854 static bool count_find_witness_calls() {
855 if (TraceDependencies || LogCompilation) {
856 int pcount = deps_find_witness_print + 1;
857 bool final_stats = (pcount == 0);
858 bool initial_call = (pcount == 1);
859 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
860 if (pcount < 0) pcount = 1; // crude overflow protection
861 deps_find_witness_print = pcount;
862 if (VerifyDependencies && initial_call) {
863 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
864 }
865 if (occasional_print || final_stats) {
866 // Every now and then dump a little info about dependency searching.
867 if (xtty != NULL) {
868 ttyLocker ttyl;
869 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
870 deps_find_witness_calls,
871 deps_find_witness_steps,
872 deps_find_witness_recursions,
873 deps_find_witness_singles);
874 }
875 if (final_stats || (TraceDependencies && WizardMode)) {
876 ttyLocker ttyl;
877 tty->print_cr("Dependency check (find_witness) "
878 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
879 deps_find_witness_calls,
880 deps_find_witness_steps,
881 (double)deps_find_witness_steps / deps_find_witness_calls,
882 deps_find_witness_recursions,
883 deps_find_witness_singles);
884 }
885 }
886 return true;
887 }
888 return false;
889 }
890 #else
891 #define count_find_witness_calls() (0)
892 #endif //PRODUCT
895 klassOop ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
896 klassOop context_type,
897 bool participants_hide_witnesses) {
898 assert(changes.involves_context(context_type), "irrelevant dependency");
899 klassOop new_type = changes.new_type();
901 count_find_witness_calls();
902 NOT_PRODUCT(deps_find_witness_singles++);
904 // Current thread must be in VM (not native mode, as in CI):
905 assert(must_be_in_vm(), "raw oops here");
906 // Must not move the class hierarchy during this check:
907 assert_locked_or_safepoint(Compile_lock);
909 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
910 if (nof_impls > 1) {
911 // Avoid this case: *I.m > { A.m, C }; B.m > C
912 // %%% Until this is fixed more systematically, bail out.
913 // See corresponding comment in find_witness_anywhere.
914 return context_type;
915 }
917 assert(!is_participant(new_type), "only old classes are participants");
918 if (participants_hide_witnesses) {
919 // If the new type is a subtype of a participant, we are done.
920 for (int i = 0; i < num_participants(); i++) {
921 klassOop part = participant(i);
922 if (part == NULL) continue;
923 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part),
924 "correct marking of participants, b/c new_type is unique");
925 if (changes.involves_context(part)) {
926 // new guy is protected from this check by previous participant
927 return NULL;
928 }
929 }
930 }
932 if (is_witness(new_type) &&
933 !ignore_witness(new_type)) {
934 return new_type;
935 }
937 return NULL;
938 }
941 // Walk hierarchy under a context type, looking for unexpected types.
942 // Do not report participant types, and recursively walk beneath
943 // them only if participants_hide_witnesses is false.
944 // If top_level_call is false, skip testing the context type,
945 // because the caller has already considered it.
946 klassOop ClassHierarchyWalker::find_witness_anywhere(klassOop context_type,
947 bool participants_hide_witnesses,
948 bool top_level_call) {
949 // Current thread must be in VM (not native mode, as in CI):
950 assert(must_be_in_vm(), "raw oops here");
951 // Must not move the class hierarchy during this check:
952 assert_locked_or_safepoint(Compile_lock);
954 bool do_counts = count_find_witness_calls();
956 // Check the root of the sub-hierarchy first.
957 if (top_level_call) {
958 if (do_counts) {
959 NOT_PRODUCT(deps_find_witness_calls++);
960 NOT_PRODUCT(deps_find_witness_steps++);
961 }
962 if (is_participant(context_type)) {
963 if (participants_hide_witnesses) return NULL;
964 // else fall through to search loop...
965 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
966 // The context is an abstract class or interface, to start with.
967 return context_type;
968 }
969 }
971 // Now we must check each implementor and each subclass.
972 // Use a short worklist to avoid blowing the stack.
973 // Each worklist entry is a *chain* of subklass siblings to process.
974 const int CHAINMAX = 100; // >= 1 + instanceKlass::implementors_limit
975 Klass* chains[CHAINMAX];
976 int chaini = 0; // index into worklist
977 Klass* chain; // scratch variable
978 #define ADD_SUBCLASS_CHAIN(k) { \
979 assert(chaini < CHAINMAX, "oob"); \
980 chain = instanceKlass::cast(k)->subklass(); \
981 if (chain != NULL) chains[chaini++] = chain; }
983 // Look for non-abstract subclasses.
984 // (Note: Interfaces do not have subclasses.)
985 ADD_SUBCLASS_CHAIN(context_type);
987 // If it is an interface, search its direct implementors.
988 // (Their subclasses are additional indirect implementors.
989 // See instanceKlass::add_implementor.)
990 // (Note: nof_implementors is always zero for non-interfaces.)
991 int nof_impls = instanceKlass::cast(context_type)->nof_implementors();
992 if (nof_impls > 1) {
993 // Avoid this case: *I.m > { A.m, C }; B.m > C
994 // Here, I.m has 2 concrete implementations, but m appears unique
995 // as A.m, because the search misses B.m when checking C.
996 // The inherited method B.m was getting missed by the walker
997 // when interface 'I' was the starting point.
998 // %%% Until this is fixed more systematically, bail out.
999 // (Old CHA had the same limitation.)
1000 return context_type;
1001 }
1002 for (int i = 0; i < nof_impls; i++) {
1003 klassOop impl = instanceKlass::cast(context_type)->implementor(i);
1004 if (impl == NULL) {
1005 // implementors array overflowed => no exact info.
1006 return context_type; // report an inexact witness to this sad affair
1007 }
1008 if (do_counts)
1009 { NOT_PRODUCT(deps_find_witness_steps++); }
1010 if (is_participant(impl)) {
1011 if (participants_hide_witnesses) continue;
1012 // else fall through to process this guy's subclasses
1013 } else if (is_witness(impl) && !ignore_witness(impl)) {
1014 return impl;
1015 }
1016 ADD_SUBCLASS_CHAIN(impl);
1017 }
1019 // Recursively process each non-trivial sibling chain.
1020 while (chaini > 0) {
1021 Klass* chain = chains[--chaini];
1022 for (Klass* subk = chain; subk != NULL; subk = subk->next_sibling()) {
1023 klassOop sub = subk->as_klassOop();
1024 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1025 if (is_participant(sub)) {
1026 if (participants_hide_witnesses) continue;
1027 // else fall through to process this guy's subclasses
1028 } else if (is_witness(sub) && !ignore_witness(sub)) {
1029 return sub;
1030 }
1031 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1032 // Fast path. (Partially disabled if VerifyDependencies.)
1033 ADD_SUBCLASS_CHAIN(sub);
1034 } else {
1035 // Worklist overflow. Do a recursive call. Should be rare.
1036 // The recursive call will have its own worklist, of course.
1037 // (Note that sub has already been tested, so that there is
1038 // no need for the recursive call to re-test. That's handy,
1039 // since the recursive call sees sub as the context_type.)
1040 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1041 klassOop witness = find_witness_anywhere(sub,
1042 participants_hide_witnesses,
1043 /*top_level_call=*/ false);
1044 if (witness != NULL) return witness;
1045 }
1046 }
1047 }
1049 // No witness found. The dependency remains unbroken.
1050 return NULL;
1051 #undef ADD_SUBCLASS_CHAIN
1052 }
1055 bool Dependencies::is_concrete_klass(klassOop k) {
1056 if (Klass::cast(k)->is_abstract()) return false;
1057 // %%% We could treat classes which are concrete but
1058 // have not yet been instantiated as virtually abstract.
1059 // This would require a deoptimization barrier on first instantiation.
1060 //if (k->is_not_instantiated()) return false;
1061 return true;
1062 }
1064 bool Dependencies::is_concrete_method(methodOop m) {
1065 if (m->is_abstract()) return false;
1066 // %%% We could treat unexecuted methods as virtually abstract also.
1067 // This would require a deoptimization barrier on first execution.
1068 return !m->is_abstract();
1069 }
1072 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1073 if (k->is_interface()) return NULL;
1074 if (k->has_finalizer()) return k;
1075 k = k->subklass();
1076 while (k != NULL) {
1077 Klass* result = find_finalizable_subclass(k);
1078 if (result != NULL) return result;
1079 k = k->next_sibling();
1080 }
1081 return NULL;
1082 }
1085 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1086 if (k->is_abstract()) return false;
1087 // We could return also false if k does not yet appear to be
1088 // instantiated, if the VM version supports this distinction also.
1089 //if (k->is_not_instantiated()) return false;
1090 return true;
1091 }
1093 bool Dependencies::is_concrete_method(ciMethod* m) {
1094 // Statics are irrelevant to virtual call sites.
1095 if (m->is_static()) return false;
1097 // We could return also false if m does not yet appear to be
1098 // executed, if the VM version supports this distinction also.
1099 return !m->is_abstract();
1100 }
1103 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1104 return k->has_finalizable_subclass();
1105 }
1108 // Any use of the contents (bytecodes) of a method must be
1109 // marked by an "evol_method" dependency, if those contents
1110 // can change. (Note: A method is always dependent on itself.)
1111 klassOop Dependencies::check_evol_method(methodOop m) {
1112 assert(must_be_in_vm(), "raw oops here");
1113 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1114 // Or is there a now a breakpoint?
1115 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1116 if (m->is_old()
1117 || m->number_of_breakpoints() > 0) {
1118 return m->method_holder();
1119 } else {
1120 return NULL;
1121 }
1122 }
1124 // This is a strong assertion: It is that the given type
1125 // has no subtypes whatever. It is most useful for
1126 // optimizing checks on reflected types or on array types.
1127 // (Checks on types which are derived from real instances
1128 // can be optimized more strongly than this, because we
1129 // know that the checked type comes from a concrete type,
1130 // and therefore we can disregard abstract types.)
1131 klassOop Dependencies::check_leaf_type(klassOop ctxk) {
1132 assert(must_be_in_vm(), "raw oops here");
1133 assert_locked_or_safepoint(Compile_lock);
1134 instanceKlass* ctx = instanceKlass::cast(ctxk);
1135 Klass* sub = ctx->subklass();
1136 if (sub != NULL) {
1137 return sub->as_klassOop();
1138 } else if (ctx->nof_implementors() != 0) {
1139 // if it is an interface, it must be unimplemented
1140 // (if it is not an interface, nof_implementors is always zero)
1141 klassOop impl = ctx->implementor(0);
1142 return (impl != NULL)? impl: ctxk;
1143 } else {
1144 return NULL;
1145 }
1146 }
1148 // Test the assertion that conck is the only concrete subtype* of ctxk.
1149 // The type conck itself is allowed to have have further concrete subtypes.
1150 // This allows the compiler to narrow occurrences of ctxk by conck,
1151 // when dealing with the types of actual instances.
1152 klassOop Dependencies::check_abstract_with_unique_concrete_subtype(klassOop ctxk,
1153 klassOop conck,
1154 KlassDepChange* changes) {
1155 ClassHierarchyWalker wf(conck);
1156 return wf.find_witness_subtype(ctxk, changes);
1157 }
1159 // If a non-concrete class has no concrete subtypes, it is not (yet)
1160 // instantiatable. This can allow the compiler to make some paths go
1161 // dead, if they are gated by a test of the type.
1162 klassOop Dependencies::check_abstract_with_no_concrete_subtype(klassOop ctxk,
1163 KlassDepChange* changes) {
1164 // Find any concrete subtype, with no participants:
1165 ClassHierarchyWalker wf;
1166 return wf.find_witness_subtype(ctxk, changes);
1167 }
1170 // If a concrete class has no concrete subtypes, it can always be
1171 // exactly typed. This allows the use of a cheaper type test.
1172 klassOop Dependencies::check_concrete_with_no_concrete_subtype(klassOop ctxk,
1173 KlassDepChange* changes) {
1174 // Find any concrete subtype, with only the ctxk as participant:
1175 ClassHierarchyWalker wf(ctxk);
1176 return wf.find_witness_subtype(ctxk, changes);
1177 }
1180 // Find the unique concrete proper subtype of ctxk, or NULL if there
1181 // is more than one concrete proper subtype. If there are no concrete
1182 // proper subtypes, return ctxk itself, whether it is concrete or not.
1183 // The returned subtype is allowed to have have further concrete subtypes.
1184 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1185 klassOop Dependencies::find_unique_concrete_subtype(klassOop ctxk) {
1186 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1187 wf.record_witnesses(1); // Record one other witness when walking.
1188 klassOop wit = wf.find_witness_subtype(ctxk);
1189 if (wit != NULL) return NULL; // Too many witnesses.
1190 klassOop conck = wf.participant(0);
1191 if (conck == NULL) {
1192 #ifndef PRODUCT
1193 // Make sure the dependency mechanism will pass this discovery:
1194 if (VerifyDependencies) {
1195 // Turn off dependency tracing while actually testing deps.
1196 FlagSetting fs(TraceDependencies, false);
1197 if (!Dependencies::is_concrete_klass(ctxk)) {
1198 guarantee(NULL ==
1199 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1200 "verify dep.");
1201 } else {
1202 guarantee(NULL ==
1203 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1204 "verify dep.");
1205 }
1206 }
1207 #endif //PRODUCT
1208 return ctxk; // Return ctxk as a flag for "no subtypes".
1209 } else {
1210 #ifndef PRODUCT
1211 // Make sure the dependency mechanism will pass this discovery:
1212 if (VerifyDependencies) {
1213 // Turn off dependency tracing while actually testing deps.
1214 FlagSetting fs(TraceDependencies, false);
1215 if (!Dependencies::is_concrete_klass(ctxk)) {
1216 guarantee(NULL == (void *)
1217 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1218 "verify dep.");
1219 }
1220 }
1221 #endif //PRODUCT
1222 return conck;
1223 }
1224 }
1226 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1227 // except possibly for further subtypes of k[12] themselves.
1228 // The context type must be abstract. The types k1 and k2 are themselves
1229 // allowed to have further concrete subtypes.
1230 klassOop Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1231 klassOop ctxk,
1232 klassOop k1,
1233 klassOop k2,
1234 KlassDepChange* changes) {
1235 ClassHierarchyWalker wf;
1236 wf.add_participant(k1);
1237 wf.add_participant(k2);
1238 return wf.find_witness_subtype(ctxk, changes);
1239 }
1241 // Search ctxk for concrete implementations. If there are klen or fewer,
1242 // pack them into the given array and return the number.
1243 // Otherwise, return -1, meaning the given array would overflow.
1244 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1245 // In this search, if ctxk is concrete, it will be reported alone.
1246 // For any type CC reported, no proper subtypes of CC will be reported.
1247 int Dependencies::find_exclusive_concrete_subtypes(klassOop ctxk,
1248 int klen,
1249 klassOop karray[]) {
1250 ClassHierarchyWalker wf;
1251 wf.record_witnesses(klen);
1252 klassOop wit = wf.find_witness_subtype(ctxk);
1253 if (wit != NULL) return -1; // Too many witnesses.
1254 int num = wf.num_participants();
1255 assert(num <= klen, "oob");
1256 // Pack the result array with the good news.
1257 for (int i = 0; i < num; i++)
1258 karray[i] = wf.participant(i);
1259 #ifndef PRODUCT
1260 // Make sure the dependency mechanism will pass this discovery:
1261 if (VerifyDependencies) {
1262 // Turn off dependency tracing while actually testing deps.
1263 FlagSetting fs(TraceDependencies, false);
1264 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1265 case -1: // ctxk was itself concrete
1266 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1267 break;
1268 case 0:
1269 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1270 "verify dep.");
1271 break;
1272 case 1:
1273 guarantee(NULL == (void *)
1274 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1275 "verify dep.");
1276 break;
1277 case 2:
1278 guarantee(NULL == (void *)
1279 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1280 karray[0],
1281 karray[1]),
1282 "verify dep.");
1283 break;
1284 default:
1285 ShouldNotReachHere(); // klen > 2 yet supported
1286 }
1287 }
1288 #endif //PRODUCT
1289 return num;
1290 }
1292 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1293 // Otherwise, return a class that contains an interfering method.
1294 klassOop Dependencies::check_unique_concrete_method(klassOop ctxk, methodOop uniqm,
1295 KlassDepChange* changes) {
1296 // Here is a missing optimization: If uniqm->is_final(),
1297 // we don't really need to search beneath it for overrides.
1298 // This is probably not important, since we don't use dependencies
1299 // to track final methods. (They can't be "definalized".)
1300 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1301 return wf.find_witness_definer(ctxk, changes);
1302 }
1304 // Find the set of all non-abstract methods under ctxk that match m.
1305 // (The method m must be defined or inherited in ctxk.)
1306 // Include m itself in the set, unless it is abstract.
1307 // If this set has exactly one element, return that element.
1308 methodOop Dependencies::find_unique_concrete_method(klassOop ctxk, methodOop m) {
1309 ClassHierarchyWalker wf(m);
1310 assert(wf.check_method_context(ctxk, m), "proper context");
1311 wf.record_witnesses(1);
1312 klassOop wit = wf.find_witness_definer(ctxk);
1313 if (wit != NULL) return NULL; // Too many witnesses.
1314 methodOop fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1315 if (Dependencies::is_concrete_method(m)) {
1316 if (fm == NULL) {
1317 // It turns out that m was always the only implementation.
1318 fm = m;
1319 } else if (fm != m) {
1320 // Two conflicting implementations after all.
1321 // (This can happen if m is inherited into ctxk and fm overrides it.)
1322 return NULL;
1323 }
1324 }
1325 #ifndef PRODUCT
1326 // Make sure the dependency mechanism will pass this discovery:
1327 if (VerifyDependencies && fm != NULL) {
1328 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1329 "verify dep.");
1330 }
1331 #endif //PRODUCT
1332 return fm;
1333 }
1335 klassOop Dependencies::check_exclusive_concrete_methods(klassOop ctxk,
1336 methodOop m1,
1337 methodOop m2,
1338 KlassDepChange* changes) {
1339 ClassHierarchyWalker wf(m1);
1340 wf.add_participant(m1->method_holder());
1341 wf.add_participant(m2->method_holder());
1342 return wf.find_witness_definer(ctxk, changes);
1343 }
1345 // Find the set of all non-abstract methods under ctxk that match m[0].
1346 // (The method m[0] must be defined or inherited in ctxk.)
1347 // Include m itself in the set, unless it is abstract.
1348 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1349 // (The length may be zero if no concrete methods are found anywhere.)
1350 // If there are too many concrete methods to fit in marray, return -1.
1351 int Dependencies::find_exclusive_concrete_methods(klassOop ctxk,
1352 int mlen,
1353 methodOop marray[]) {
1354 methodOop m0 = marray[0];
1355 ClassHierarchyWalker wf(m0);
1356 assert(wf.check_method_context(ctxk, m0), "proper context");
1357 wf.record_witnesses(mlen);
1358 bool participants_hide_witnesses = true;
1359 klassOop wit = wf.find_witness_definer(ctxk);
1360 if (wit != NULL) return -1; // Too many witnesses.
1361 int num = wf.num_participants();
1362 assert(num <= mlen, "oob");
1363 // Keep track of whether m is also part of the result set.
1364 int mfill = 0;
1365 assert(marray[mfill] == m0, "sanity");
1366 if (Dependencies::is_concrete_method(m0))
1367 mfill++; // keep m0 as marray[0], the first result
1368 for (int i = 0; i < num; i++) {
1369 methodOop fm = wf.found_method(i);
1370 if (fm == m0) continue; // Already put this guy in the list.
1371 if (mfill == mlen) {
1372 return -1; // Oops. Too many methods after all!
1373 }
1374 marray[mfill++] = fm;
1375 }
1376 #ifndef PRODUCT
1377 // Make sure the dependency mechanism will pass this discovery:
1378 if (VerifyDependencies) {
1379 // Turn off dependency tracing while actually testing deps.
1380 FlagSetting fs(TraceDependencies, false);
1381 switch (mfill) {
1382 case 1:
1383 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1384 "verify dep.");
1385 break;
1386 case 2:
1387 guarantee(NULL == (void *)
1388 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1389 "verify dep.");
1390 break;
1391 default:
1392 ShouldNotReachHere(); // mlen > 2 yet supported
1393 }
1394 }
1395 #endif //PRODUCT
1396 return mfill;
1397 }
1400 klassOop Dependencies::check_has_no_finalizable_subclasses(klassOop ctxk, KlassDepChange* changes) {
1401 Klass* search_at = ctxk->klass_part();
1402 if (changes != NULL)
1403 search_at = changes->new_type()->klass_part(); // just look at the new bit
1404 Klass* result = find_finalizable_subclass(search_at);
1405 if (result == NULL) {
1406 return NULL;
1407 }
1408 return result->as_klassOop();
1409 }
1412 klassOop Dependencies::check_call_site_target_value(klassOop ctxk, oop call_site, oop method_handle, CallSiteDepChange* changes) {
1413 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1414 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1415 if (changes == NULL) {
1416 // Validate all CallSites
1417 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1418 return ctxk; // assertion failed
1419 } else {
1420 // Validate the given CallSite
1421 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1422 assert(method_handle != changes->method_handle(), "must be");
1423 return ctxk; // assertion failed
1424 }
1425 }
1426 assert(java_lang_invoke_CallSite::target(call_site) == method_handle, "should still be valid");
1427 return NULL; // assertion still valid
1428 }
1431 void Dependencies::DepStream::trace_and_log_witness(klassOop witness) {
1432 if (witness != NULL) {
1433 if (TraceDependencies) {
1434 print_dependency(witness, /*verbose=*/ true);
1435 }
1436 // The following is a no-op unless logging is enabled:
1437 log_dependency(witness);
1438 }
1439 }
1442 klassOop Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1443 assert_locked_or_safepoint(Compile_lock);
1444 Dependencies::check_valid_dependency_type(type());
1446 klassOop witness = NULL;
1447 switch (type()) {
1448 case evol_method:
1449 witness = check_evol_method(method_argument(0));
1450 break;
1451 case leaf_type:
1452 witness = check_leaf_type(context_type());
1453 break;
1454 case abstract_with_unique_concrete_subtype:
1455 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1456 break;
1457 case abstract_with_no_concrete_subtype:
1458 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1459 break;
1460 case concrete_with_no_concrete_subtype:
1461 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1462 break;
1463 case unique_concrete_method:
1464 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1465 break;
1466 case abstract_with_exclusive_concrete_subtypes_2:
1467 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1468 break;
1469 case exclusive_concrete_methods_2:
1470 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1471 break;
1472 case no_finalizable_subclasses:
1473 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1474 break;
1475 default:
1476 witness = NULL;
1477 break;
1478 }
1479 trace_and_log_witness(witness);
1480 return witness;
1481 }
1484 klassOop Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1485 assert_locked_or_safepoint(Compile_lock);
1486 Dependencies::check_valid_dependency_type(type());
1488 klassOop witness = NULL;
1489 switch (type()) {
1490 case call_site_target_value:
1491 witness = check_call_site_target_value(context_type(), argument(1), argument(2), changes);
1492 break;
1493 default:
1494 witness = NULL;
1495 break;
1496 }
1497 trace_and_log_witness(witness);
1498 return witness;
1499 }
1502 klassOop Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1503 // Handle klass dependency
1504 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1505 return check_klass_dependency(changes.as_klass_change());
1507 // Handle CallSite dependency
1508 if (changes.is_call_site_change())
1509 return check_call_site_dependency(changes.as_call_site_change());
1511 // irrelevant dependency; skip it
1512 return NULL;
1513 }
1516 void DepChange::print() {
1517 int nsup = 0, nint = 0;
1518 for (ContextStream str(*this); str.next(); ) {
1519 klassOop k = str.klass();
1520 switch (str.change_type()) {
1521 case Change_new_type:
1522 tty->print_cr(" dependee = %s", instanceKlass::cast(k)->external_name());
1523 break;
1524 case Change_new_sub:
1525 if (!WizardMode) {
1526 ++nsup;
1527 } else {
1528 tty->print_cr(" context super = %s", instanceKlass::cast(k)->external_name());
1529 }
1530 break;
1531 case Change_new_impl:
1532 if (!WizardMode) {
1533 ++nint;
1534 } else {
1535 tty->print_cr(" context interface = %s", instanceKlass::cast(k)->external_name());
1536 }
1537 break;
1538 }
1539 }
1540 if (nsup + nint != 0) {
1541 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1542 }
1543 }
1545 void DepChange::ContextStream::start() {
1546 klassOop new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (klassOop) NULL;
1547 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1548 _klass = new_type;
1549 _ti_base = NULL;
1550 _ti_index = 0;
1551 _ti_limit = 0;
1552 }
1554 bool DepChange::ContextStream::next() {
1555 switch (_change_type) {
1556 case Start_Klass: // initial state; _klass is the new type
1557 _ti_base = instanceKlass::cast(_klass)->transitive_interfaces();
1558 _ti_index = 0;
1559 _change_type = Change_new_type;
1560 return true;
1561 case Change_new_type:
1562 // fall through:
1563 _change_type = Change_new_sub;
1564 case Change_new_sub:
1565 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1566 {
1567 _klass = instanceKlass::cast(_klass)->super();
1568 if (_klass != NULL) {
1569 return true;
1570 }
1571 }
1572 // else set up _ti_limit and fall through:
1573 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1574 _change_type = Change_new_impl;
1575 case Change_new_impl:
1576 if (_ti_index < _ti_limit) {
1577 _klass = klassOop( _ti_base->obj_at(_ti_index++) );
1578 return true;
1579 }
1580 // fall through:
1581 _change_type = NO_CHANGE; // iterator is exhausted
1582 case NO_CHANGE:
1583 break;
1584 default:
1585 ShouldNotReachHere();
1586 }
1587 return false;
1588 }
1590 void KlassDepChange::initialize() {
1591 // entire transaction must be under this lock:
1592 assert_lock_strong(Compile_lock);
1594 // Mark all dependee and all its superclasses
1595 // Mark transitive interfaces
1596 for (ContextStream str(*this); str.next(); ) {
1597 klassOop d = str.klass();
1598 assert(!instanceKlass::cast(d)->is_marked_dependent(), "checking");
1599 instanceKlass::cast(d)->set_is_marked_dependent(true);
1600 }
1601 }
1603 KlassDepChange::~KlassDepChange() {
1604 // Unmark all dependee and all its superclasses
1605 // Unmark transitive interfaces
1606 for (ContextStream str(*this); str.next(); ) {
1607 klassOop d = str.klass();
1608 instanceKlass::cast(d)->set_is_marked_dependent(false);
1609 }
1610 }
1612 bool KlassDepChange::involves_context(klassOop k) {
1613 if (k == NULL || !Klass::cast(k)->oop_is_instance()) {
1614 return false;
1615 }
1616 instanceKlass* ik = instanceKlass::cast(k);
1617 bool is_contained = ik->is_marked_dependent();
1618 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k),
1619 "correct marking of potential context types");
1620 return is_contained;
1621 }
1623 #ifndef PRODUCT
1624 void Dependencies::print_statistics() {
1625 if (deps_find_witness_print != 0) {
1626 // Call one final time, to flush out the data.
1627 deps_find_witness_print = -1;
1628 count_find_witness_calls();
1629 }
1630 }
1631 #endif