Thu, 11 Oct 2012 12:25:42 -0400
7200776: Implement default methods in interfaces
Summary: Add generic type analysis and default method selection algorithms
Reviewed-by: coleenp, acorn
1 /*
2 * Copyright (c) 2005, 2012, 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.hpp"
34 #include "runtime/handles.inline.hpp"
35 #include "utilities/copy.hpp"
38 #ifdef ASSERT
39 static bool must_be_in_vm() {
40 Thread* thread = Thread::current();
41 if (thread->is_Java_thread())
42 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
43 else
44 return true; //something like this: thread->is_VM_thread();
45 }
46 #endif //ASSERT
48 void Dependencies::initialize(ciEnv* env) {
49 Arena* arena = env->arena();
50 _oop_recorder = env->oop_recorder();
51 _log = env->log();
52 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
53 DEBUG_ONLY(_deps[end_marker] = NULL);
54 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
55 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
56 }
57 _content_bytes = NULL;
58 _size_in_bytes = (size_t)-1;
60 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
61 }
63 void Dependencies::assert_evol_method(ciMethod* m) {
64 assert_common_1(evol_method, m);
65 }
67 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
68 if (ctxk->is_array_klass()) {
69 // As a special case, support this assertion on an array type,
70 // which reduces to an assertion on its element type.
71 // Note that this cannot be done with assertions that
72 // relate to concreteness or abstractness.
73 ciType* elemt = ctxk->as_array_klass()->base_element_type();
74 if (!elemt->is_instance_klass()) return; // Ex: int[][]
75 ctxk = elemt->as_instance_klass();
76 //if (ctxk->is_final()) return; // Ex: String[][]
77 }
78 check_ctxk(ctxk);
79 assert_common_1(leaf_type, ctxk);
80 }
82 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
83 check_ctxk_abstract(ctxk);
84 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
85 }
87 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
88 check_ctxk_abstract(ctxk);
89 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
90 }
92 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
93 check_ctxk_concrete(ctxk);
94 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
95 }
97 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
98 check_ctxk(ctxk);
99 assert_common_2(unique_concrete_method, ctxk, uniqm);
100 }
102 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
103 check_ctxk(ctxk);
104 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
105 }
107 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
108 check_ctxk(ctxk);
109 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
110 }
112 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
113 check_ctxk(ctxk);
114 assert_common_1(no_finalizable_subclasses, ctxk);
115 }
117 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
118 check_ctxk(call_site->klass());
119 assert_common_2(call_site_target_value, call_site, method_handle);
120 }
122 // Helper function. If we are adding a new dep. under ctxk2,
123 // try to find an old dep. under a broader* ctxk1. If there is
124 //
125 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
126 int ctxk_i, ciKlass* ctxk2) {
127 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
128 if (ctxk2->is_subtype_of(ctxk1)) {
129 return true; // success, and no need to change
130 } else if (ctxk1->is_subtype_of(ctxk2)) {
131 // new context class fully subsumes previous one
132 deps->at_put(ctxk_i, ctxk2);
133 return true;
134 } else {
135 return false;
136 }
137 }
139 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
140 assert(dep_args(dept) == 1, "sanity");
141 log_dependency(dept, x);
142 GrowableArray<ciBaseObject*>* deps = _deps[dept];
144 // see if the same (or a similar) dep is already recorded
145 if (note_dep_seen(dept, x)) {
146 assert(deps->find(x) >= 0, "sanity");
147 } else {
148 deps->append(x);
149 }
150 }
152 void Dependencies::assert_common_2(DepType dept,
153 ciBaseObject* x0, ciBaseObject* x1) {
154 assert(dep_args(dept) == 2, "sanity");
155 log_dependency(dept, x0, x1);
156 GrowableArray<ciBaseObject*>* deps = _deps[dept];
158 // see if the same (or a similar) dep is already recorded
159 bool has_ctxk = has_explicit_context_arg(dept);
160 if (has_ctxk) {
161 assert(dep_context_arg(dept) == 0, "sanity");
162 if (note_dep_seen(dept, x1)) {
163 // look in this bucket for redundant assertions
164 const int stride = 2;
165 for (int i = deps->length(); (i -= stride) >= 0; ) {
166 ciBaseObject* y1 = deps->at(i+1);
167 if (x1 == y1) { // same subject; check the context
168 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
169 return;
170 }
171 }
172 }
173 }
174 } else {
175 assert(dep_implicit_context_arg(dept) == 0, "sanity");
176 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
177 // look in this bucket for redundant assertions
178 const int stride = 2;
179 for (int i = deps->length(); (i -= stride) >= 0; ) {
180 ciBaseObject* y0 = deps->at(i+0);
181 ciBaseObject* y1 = deps->at(i+1);
182 if (x0 == y0 && x1 == y1) {
183 return;
184 }
185 }
186 }
187 }
189 // append the assertion in the correct bucket:
190 deps->append(x0);
191 deps->append(x1);
192 }
194 void Dependencies::assert_common_3(DepType dept,
195 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
196 assert(dep_context_arg(dept) == 0, "sanity");
197 assert(dep_args(dept) == 3, "sanity");
198 log_dependency(dept, ctxk, x, x2);
199 GrowableArray<ciBaseObject*>* deps = _deps[dept];
201 // try to normalize an unordered pair:
202 bool swap = false;
203 switch (dept) {
204 case abstract_with_exclusive_concrete_subtypes_2:
205 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
206 break;
207 case exclusive_concrete_methods_2:
208 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
209 break;
210 }
211 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
213 // see if the same (or a similar) dep is already recorded
214 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
215 // look in this bucket for redundant assertions
216 const int stride = 3;
217 for (int i = deps->length(); (i -= stride) >= 0; ) {
218 ciBaseObject* y = deps->at(i+1);
219 ciBaseObject* y2 = deps->at(i+2);
220 if (x == y && x2 == y2) { // same subjects; check the context
221 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
222 return;
223 }
224 }
225 }
226 }
227 // append the assertion in the correct bucket:
228 deps->append(ctxk);
229 deps->append(x);
230 deps->append(x2);
231 }
233 /// Support for encoding dependencies into an nmethod:
235 void Dependencies::copy_to(nmethod* nm) {
236 address beg = nm->dependencies_begin();
237 address end = nm->dependencies_end();
238 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
239 Copy::disjoint_words((HeapWord*) content_bytes(),
240 (HeapWord*) beg,
241 size_in_bytes() / sizeof(HeapWord));
242 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
243 }
245 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
246 for (int i = 0; i < narg; i++) {
247 int diff = p1[i]->ident() - p2[i]->ident();
248 if (diff != 0) return diff;
249 }
250 return 0;
251 }
252 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
253 { return sort_dep(p1, p2, 1); }
254 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
255 { return sort_dep(p1, p2, 2); }
256 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
257 { return sort_dep(p1, p2, 3); }
259 void Dependencies::sort_all_deps() {
260 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
261 DepType dept = (DepType)deptv;
262 GrowableArray<ciBaseObject*>* deps = _deps[dept];
263 if (deps->length() <= 1) continue;
264 switch (dep_args(dept)) {
265 case 1: deps->sort(sort_dep_arg_1, 1); break;
266 case 2: deps->sort(sort_dep_arg_2, 2); break;
267 case 3: deps->sort(sort_dep_arg_3, 3); break;
268 default: ShouldNotReachHere();
269 }
270 }
271 }
273 size_t Dependencies::estimate_size_in_bytes() {
274 size_t est_size = 100;
275 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
276 DepType dept = (DepType)deptv;
277 GrowableArray<ciBaseObject*>* deps = _deps[dept];
278 est_size += deps->length()*2; // tags and argument(s)
279 }
280 return est_size;
281 }
283 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
284 switch (dept) {
285 case abstract_with_exclusive_concrete_subtypes_2:
286 return x->as_metadata()->as_klass();
287 case unique_concrete_method:
288 case exclusive_concrete_methods_2:
289 return x->as_metadata()->as_method()->holder();
290 }
291 return NULL; // let NULL be NULL
292 }
294 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
295 assert(must_be_in_vm(), "raw oops here");
296 switch (dept) {
297 case abstract_with_exclusive_concrete_subtypes_2:
298 assert(x->is_klass(), "sanity");
299 return (Klass*) x;
300 case unique_concrete_method:
301 case exclusive_concrete_methods_2:
302 assert(x->is_method(), "sanity");
303 return ((Method*)x)->method_holder();
304 }
305 return NULL; // let NULL be NULL
306 }
308 void Dependencies::encode_content_bytes() {
309 sort_all_deps();
311 // cast is safe, no deps can overflow INT_MAX
312 CompressedWriteStream bytes((int)estimate_size_in_bytes());
314 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
315 DepType dept = (DepType)deptv;
316 GrowableArray<ciBaseObject*>* deps = _deps[dept];
317 if (deps->length() == 0) continue;
318 int stride = dep_args(dept);
319 int ctxkj = dep_context_arg(dept); // -1 if no context arg
320 assert(stride > 0, "sanity");
321 for (int i = 0; i < deps->length(); i += stride) {
322 jbyte code_byte = (jbyte)dept;
323 int skipj = -1;
324 if (ctxkj >= 0 && ctxkj+1 < stride) {
325 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
326 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
327 if (ctxk == ctxk_encoded_as_null(dept, x)) {
328 skipj = ctxkj; // we win: maybe one less oop to keep track of
329 code_byte |= default_context_type_bit;
330 }
331 }
332 bytes.write_byte(code_byte);
333 for (int j = 0; j < stride; j++) {
334 if (j == skipj) continue;
335 ciBaseObject* v = deps->at(i+j);
336 int idx;
337 if (v->is_object()) {
338 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
339 } else {
340 ciMetadata* meta = v->as_metadata();
341 idx = _oop_recorder->find_index(meta->constant_encoding());
342 }
343 bytes.write_int(idx);
344 }
345 }
346 }
348 // write a sentinel byte to mark the end
349 bytes.write_byte(end_marker);
351 // round it out to a word boundary
352 while (bytes.position() % sizeof(HeapWord) != 0) {
353 bytes.write_byte(end_marker);
354 }
356 // check whether the dept byte encoding really works
357 assert((jbyte)default_context_type_bit != 0, "byte overflow");
359 _content_bytes = bytes.buffer();
360 _size_in_bytes = bytes.position();
361 }
364 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
365 "end_marker",
366 "evol_method",
367 "leaf_type",
368 "abstract_with_unique_concrete_subtype",
369 "abstract_with_no_concrete_subtype",
370 "concrete_with_no_concrete_subtype",
371 "unique_concrete_method",
372 "abstract_with_exclusive_concrete_subtypes_2",
373 "exclusive_concrete_methods_2",
374 "no_finalizable_subclasses",
375 "call_site_target_value"
376 };
378 int Dependencies::_dep_args[TYPE_LIMIT] = {
379 -1,// end_marker
380 1, // evol_method m
381 1, // leaf_type ctxk
382 2, // abstract_with_unique_concrete_subtype ctxk, k
383 1, // abstract_with_no_concrete_subtype ctxk
384 1, // concrete_with_no_concrete_subtype ctxk
385 2, // unique_concrete_method ctxk, m
386 3, // unique_concrete_subtypes_2 ctxk, k1, k2
387 3, // unique_concrete_methods_2 ctxk, m1, m2
388 1, // no_finalizable_subclasses ctxk
389 2 // call_site_target_value call_site, method_handle
390 };
392 const char* Dependencies::dep_name(Dependencies::DepType dept) {
393 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
394 return _dep_name[dept];
395 }
397 int Dependencies::dep_args(Dependencies::DepType dept) {
398 if (!dept_in_mask(dept, all_types)) return -1;
399 return _dep_args[dept];
400 }
402 void Dependencies::check_valid_dependency_type(DepType dept) {
403 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
404 }
406 // for the sake of the compiler log, print out current dependencies:
407 void Dependencies::log_all_dependencies() {
408 if (log() == NULL) return;
409 ciBaseObject* args[max_arg_count];
410 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
411 DepType dept = (DepType)deptv;
412 GrowableArray<ciBaseObject*>* deps = _deps[dept];
413 if (deps->length() == 0) continue;
414 int stride = dep_args(dept);
415 for (int i = 0; i < deps->length(); i += stride) {
416 for (int j = 0; j < stride; j++) {
417 // flush out the identities before printing
418 args[j] = deps->at(i+j);
419 }
420 write_dependency_to(log(), dept, stride, args);
421 }
422 }
423 }
425 void Dependencies::write_dependency_to(CompileLog* log,
426 DepType dept,
427 int nargs, DepArgument args[],
428 Klass* witness) {
429 if (log == NULL) {
430 return;
431 }
432 ciEnv* env = ciEnv::current();
433 ciBaseObject* ciargs[max_arg_count];
434 assert(nargs <= max_arg_count, "oob");
435 for (int j = 0; j < nargs; j++) {
436 if (args[j].is_oop()) {
437 ciargs[j] = env->get_object(args[j].oop_value());
438 } else {
439 ciargs[j] = env->get_metadata(args[j].metadata_value());
440 }
441 }
442 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
443 }
445 void Dependencies::write_dependency_to(CompileLog* log,
446 DepType dept,
447 int nargs, ciBaseObject* args[],
448 Klass* witness) {
449 if (log == NULL) return;
450 assert(nargs <= max_arg_count, "oob");
451 int argids[max_arg_count];
452 int ctxkj = dep_context_arg(dept); // -1 if no context arg
453 int j;
454 for (j = 0; j < nargs; j++) {
455 if (args[j]->is_object()) {
456 argids[j] = log->identify(args[j]->as_object());
457 } else {
458 argids[j] = log->identify(args[j]->as_metadata());
459 }
460 }
461 if (witness != NULL) {
462 log->begin_elem("dependency_failed");
463 } else {
464 log->begin_elem("dependency");
465 }
466 log->print(" type='%s'", dep_name(dept));
467 if (ctxkj >= 0) {
468 log->print(" ctxk='%d'", argids[ctxkj]);
469 }
470 // write remaining arguments, if any.
471 for (j = 0; j < nargs; j++) {
472 if (j == ctxkj) continue; // already logged
473 if (j == 1) {
474 log->print( " x='%d'", argids[j]);
475 } else {
476 log->print(" x%d='%d'", j, argids[j]);
477 }
478 }
479 if (witness != NULL) {
480 log->object("witness", witness);
481 log->stamp();
482 }
483 log->end_elem();
484 }
486 void Dependencies::write_dependency_to(xmlStream* xtty,
487 DepType dept,
488 int nargs, DepArgument args[],
489 Klass* witness) {
490 if (xtty == NULL) return;
491 ttyLocker ttyl;
492 int ctxkj = dep_context_arg(dept); // -1 if no context arg
493 if (witness != NULL) {
494 xtty->begin_elem("dependency_failed");
495 } else {
496 xtty->begin_elem("dependency");
497 }
498 xtty->print(" type='%s'", dep_name(dept));
499 if (ctxkj >= 0) {
500 xtty->object("ctxk", args[ctxkj].metadata_value());
501 }
502 // write remaining arguments, if any.
503 for (int j = 0; j < nargs; j++) {
504 if (j == ctxkj) continue; // already logged
505 if (j == 1) {
506 if (args[j].is_oop()) {
507 xtty->object("x", args[j].oop_value());
508 } else {
509 xtty->object("x", args[j].metadata_value());
510 }
511 } else {
512 char xn[10]; sprintf(xn, "x%d", j);
513 if (args[j].is_oop()) {
514 xtty->object(xn, args[j].oop_value());
515 } else {
516 xtty->object(xn, args[j].metadata_value());
517 }
518 }
519 }
520 if (witness != NULL) {
521 xtty->object("witness", witness);
522 xtty->stamp();
523 }
524 xtty->end_elem();
525 }
527 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[],
528 Klass* witness) {
529 ResourceMark rm;
530 ttyLocker ttyl; // keep the following output all in one block
531 tty->print_cr("%s of type %s",
532 (witness == NULL)? "Dependency": "Failed dependency",
533 dep_name(dept));
534 // print arguments
535 int ctxkj = dep_context_arg(dept); // -1 if no context arg
536 for (int j = 0; j < nargs; j++) {
537 DepArgument arg = args[j];
538 bool put_star = false;
539 if (arg.is_null()) continue;
540 const char* what;
541 if (j == ctxkj) {
542 assert(arg.is_metadata(), "must be");
543 what = "context";
544 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
545 } else if (arg.is_method()) {
546 what = "method ";
547 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value());
548 } else if (arg.is_klass()) {
549 what = "class ";
550 } else {
551 what = "object ";
552 }
553 tty->print(" %s = %s", what, (put_star? "*": ""));
554 if (arg.is_klass())
555 tty->print("%s", Klass::cast((Klass*)arg.metadata_value())->external_name());
556 else if (arg.is_method())
557 ((Method*)arg.metadata_value())->print_value();
558 else
559 ShouldNotReachHere(); // Provide impl for this type.
560 tty->cr();
561 }
562 if (witness != NULL) {
563 bool put_star = !Dependencies::is_concrete_klass(witness);
564 tty->print_cr(" witness = %s%s",
565 (put_star? "*": ""),
566 Klass::cast(witness)->external_name());
567 }
568 }
570 void Dependencies::DepStream::log_dependency(Klass* witness) {
571 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
572 int nargs = argument_count();
573 DepArgument args[max_arg_count];
574 for (int j = 0; j < nargs; j++) {
575 if (type() == call_site_target_value) {
576 args[j] = argument_oop(j);
577 } else {
578 args[j] = argument(j);
579 }
580 }
581 if (_deps != NULL && _deps->log() != NULL) {
582 Dependencies::write_dependency_to(_deps->log(),
583 type(), nargs, args, witness);
584 } else {
585 Dependencies::write_dependency_to(xtty,
586 type(), nargs, args, witness);
587 }
588 }
590 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
591 int nargs = argument_count();
592 DepArgument args[max_arg_count];
593 for (int j = 0; j < nargs; j++) {
594 args[j] = argument(j);
595 }
596 Dependencies::print_dependency(type(), nargs, args, witness);
597 if (verbose) {
598 if (_code != NULL) {
599 tty->print(" code: ");
600 _code->print_value_on(tty);
601 tty->cr();
602 }
603 }
604 }
607 /// Dependency stream support (decodes dependencies from an nmethod):
609 #ifdef ASSERT
610 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
611 assert(must_be_in_vm(), "raw oops here");
612 _byte_limit = byte_limit;
613 _type = (DepType)(end_marker-1); // defeat "already at end" assert
614 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
615 }
616 #endif //ASSERT
618 bool Dependencies::DepStream::next() {
619 assert(_type != end_marker, "already at end");
620 if (_bytes.position() == 0 && _code != NULL
621 && _code->dependencies_size() == 0) {
622 // Method has no dependencies at all.
623 return false;
624 }
625 int code_byte = (_bytes.read_byte() & 0xFF);
626 if (code_byte == end_marker) {
627 DEBUG_ONLY(_type = end_marker);
628 return false;
629 } else {
630 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
631 code_byte -= ctxk_bit;
632 DepType dept = (DepType)code_byte;
633 _type = dept;
634 Dependencies::check_valid_dependency_type(dept);
635 int stride = _dep_args[dept];
636 assert(stride == dep_args(dept), "sanity");
637 int skipj = -1;
638 if (ctxk_bit != 0) {
639 skipj = 0; // currently the only context argument is at zero
640 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
641 }
642 for (int j = 0; j < stride; j++) {
643 _xi[j] = (j == skipj)? 0: _bytes.read_int();
644 }
645 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
646 return true;
647 }
648 }
650 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
651 Metadata* o = NULL;
652 if (_code != NULL) {
653 o = _code->metadata_at(i);
654 } else {
655 o = _deps->oop_recorder()->metadata_at(i);
656 }
657 assert(o == NULL || o->is_metadata(),
658 err_msg("Should be perm " PTR_FORMAT, o));
659 return o;
660 }
662 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
663 return (_code != NULL)
664 ? _code->oop_at(i)
665 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
666 }
668 Metadata* Dependencies::DepStream::argument(int i) {
669 Metadata* result = recorded_metadata_at(argument_index(i));
671 if (result == NULL) { // Explicit context argument can be compressed
672 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
673 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
674 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
675 }
676 }
678 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
679 return result;
680 }
682 oop Dependencies::DepStream::argument_oop(int i) {
683 oop result = recorded_oop_at(argument_index(i));
684 assert(result == NULL || result->is_oop(), "must be");
685 return result;
686 }
688 Klass* Dependencies::DepStream::context_type() {
689 assert(must_be_in_vm(), "raw oops here");
691 // Most dependencies have an explicit context type argument.
692 {
693 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
694 if (ctxkj >= 0) {
695 Metadata* k = argument(ctxkj);
696 assert(k != NULL && k->is_klass(), "type check");
697 return (Klass*)k;
698 }
699 }
701 // Some dependencies are using the klass of the first object
702 // argument as implicit context type (e.g. call_site_target_value).
703 {
704 int ctxkj = dep_implicit_context_arg(type());
705 if (ctxkj >= 0) {
706 Klass* k = argument_oop(ctxkj)->klass();
707 assert(k != NULL && k->is_klass(), "type check");
708 return (Klass*) k;
709 }
710 }
712 // And some dependencies don't have a context type at all,
713 // e.g. evol_method.
714 return NULL;
715 }
717 /// Checking dependencies:
719 // This hierarchy walker inspects subtypes of a given type,
720 // trying to find a "bad" class which breaks a dependency.
721 // Such a class is called a "witness" to the broken dependency.
722 // While searching around, we ignore "participants", which
723 // are already known to the dependency.
724 class ClassHierarchyWalker {
725 public:
726 enum { PARTICIPANT_LIMIT = 3 };
728 private:
729 // optional method descriptor to check for:
730 Symbol* _name;
731 Symbol* _signature;
733 // special classes which are not allowed to be witnesses:
734 Klass* _participants[PARTICIPANT_LIMIT+1];
735 int _num_participants;
737 // cache of method lookups
738 Method* _found_methods[PARTICIPANT_LIMIT+1];
740 // if non-zero, tells how many witnesses to convert to participants
741 int _record_witnesses;
743 void initialize(Klass* participant) {
744 _record_witnesses = 0;
745 _participants[0] = participant;
746 _found_methods[0] = NULL;
747 _num_participants = 0;
748 if (participant != NULL) {
749 // Terminating NULL.
750 _participants[1] = NULL;
751 _found_methods[1] = NULL;
752 _num_participants = 1;
753 }
754 }
756 void initialize_from_method(Method* m) {
757 assert(m != NULL && m->is_method(), "sanity");
758 _name = m->name();
759 _signature = m->signature();
760 }
762 public:
763 // The walker is initialized to recognize certain methods and/or types
764 // as friendly participants.
765 ClassHierarchyWalker(Klass* participant, Method* m) {
766 initialize_from_method(m);
767 initialize(participant);
768 }
769 ClassHierarchyWalker(Method* m) {
770 initialize_from_method(m);
771 initialize(NULL);
772 }
773 ClassHierarchyWalker(Klass* participant = NULL) {
774 _name = NULL;
775 _signature = NULL;
776 initialize(participant);
777 }
779 // This is common code for two searches: One for concrete subtypes,
780 // the other for concrete method implementations and overrides.
781 bool doing_subtype_search() {
782 return _name == NULL;
783 }
785 int num_participants() { return _num_participants; }
786 Klass* participant(int n) {
787 assert((uint)n <= (uint)_num_participants, "oob");
788 return _participants[n];
789 }
791 // Note: If n==num_participants, returns NULL.
792 Method* found_method(int n) {
793 assert((uint)n <= (uint)_num_participants, "oob");
794 Method* fm = _found_methods[n];
795 assert(n == _num_participants || fm != NULL, "proper usage");
796 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
797 return fm;
798 }
800 #ifdef ASSERT
801 // Assert that m is inherited into ctxk, without intervening overrides.
802 // (May return true even if this is not true, in corner cases where we punt.)
803 bool check_method_context(Klass* ctxk, Method* m) {
804 if (m->method_holder() == ctxk)
805 return true; // Quick win.
806 if (m->is_private())
807 return false; // Quick lose. Should not happen.
808 if (!(m->is_public() || m->is_protected()))
809 // The override story is complex when packages get involved.
810 return true; // Must punt the assertion to true.
811 Klass* k = Klass::cast(ctxk);
812 Method* lm = k->lookup_method(m->name(), m->signature());
813 if (lm == NULL && k->oop_is_instance()) {
814 // It might be an abstract interface method, devoid of mirandas.
815 lm = ((InstanceKlass*)k)->lookup_method_in_all_interfaces(m->name(),
816 m->signature());
817 }
818 if (lm == m)
819 // Method m is inherited into ctxk.
820 return true;
821 if (lm != NULL) {
822 if (!(lm->is_public() || lm->is_protected())) {
823 // Method is [package-]private, so the override story is complex.
824 return true; // Must punt the assertion to true.
825 }
826 if (lm->is_static()) {
827 // Static methods don't override non-static so punt
828 return true;
829 }
830 if ( !Dependencies::is_concrete_method(lm)
831 && !Dependencies::is_concrete_method(m)
832 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder()))
833 // Method m is overridden by lm, but both are non-concrete.
834 return true;
835 }
836 ResourceMark rm;
837 tty->print_cr("Dependency method not found in the associated context:");
838 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name());
839 tty->print( " method = "); m->print_short_name(tty); tty->cr();
840 if (lm != NULL) {
841 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
842 }
843 return false;
844 }
845 #endif
847 void add_participant(Klass* participant) {
848 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
849 int np = _num_participants++;
850 _participants[np] = participant;
851 _participants[np+1] = NULL;
852 _found_methods[np+1] = NULL;
853 }
855 void record_witnesses(int add) {
856 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
857 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
858 _record_witnesses = add;
859 }
861 bool is_witness(Klass* k) {
862 if (doing_subtype_search()) {
863 return Dependencies::is_concrete_klass(k);
864 } else {
865 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature);
866 if (m == NULL || !Dependencies::is_concrete_method(m)) return false;
867 _found_methods[_num_participants] = m;
868 // Note: If add_participant(k) is called,
869 // the method m will already be memoized for it.
870 return true;
871 }
872 }
874 bool is_participant(Klass* k) {
875 if (k == _participants[0]) {
876 return true;
877 } else if (_num_participants <= 1) {
878 return false;
879 } else {
880 return in_list(k, &_participants[1]);
881 }
882 }
883 bool ignore_witness(Klass* witness) {
884 if (_record_witnesses == 0) {
885 return false;
886 } else {
887 --_record_witnesses;
888 add_participant(witness);
889 return true;
890 }
891 }
892 static bool in_list(Klass* x, Klass** list) {
893 for (int i = 0; ; i++) {
894 Klass* y = list[i];
895 if (y == NULL) break;
896 if (y == x) return true;
897 }
898 return false; // not in list
899 }
901 private:
902 // the actual search method:
903 Klass* find_witness_anywhere(Klass* context_type,
904 bool participants_hide_witnesses,
905 bool top_level_call = true);
906 // the spot-checking version:
907 Klass* find_witness_in(KlassDepChange& changes,
908 Klass* context_type,
909 bool participants_hide_witnesses);
910 public:
911 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
912 assert(doing_subtype_search(), "must set up a subtype search");
913 // When looking for unexpected concrete types,
914 // do not look beneath expected ones.
915 const bool participants_hide_witnesses = true;
916 // CX > CC > C' is OK, even if C' is new.
917 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
918 if (changes != NULL) {
919 return find_witness_in(*changes, context_type, participants_hide_witnesses);
920 } else {
921 return find_witness_anywhere(context_type, participants_hide_witnesses);
922 }
923 }
924 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
925 assert(!doing_subtype_search(), "must set up a method definer search");
926 // When looking for unexpected concrete methods,
927 // look beneath expected ones, to see if there are overrides.
928 const bool participants_hide_witnesses = true;
929 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
930 if (changes != NULL) {
931 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
932 } else {
933 return find_witness_anywhere(context_type, !participants_hide_witnesses);
934 }
935 }
936 };
938 #ifndef PRODUCT
939 static int deps_find_witness_calls = 0;
940 static int deps_find_witness_steps = 0;
941 static int deps_find_witness_recursions = 0;
942 static int deps_find_witness_singles = 0;
943 static int deps_find_witness_print = 0; // set to -1 to force a final print
944 static bool count_find_witness_calls() {
945 if (TraceDependencies || LogCompilation) {
946 int pcount = deps_find_witness_print + 1;
947 bool final_stats = (pcount == 0);
948 bool initial_call = (pcount == 1);
949 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
950 if (pcount < 0) pcount = 1; // crude overflow protection
951 deps_find_witness_print = pcount;
952 if (VerifyDependencies && initial_call) {
953 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
954 }
955 if (occasional_print || final_stats) {
956 // Every now and then dump a little info about dependency searching.
957 if (xtty != NULL) {
958 ttyLocker ttyl;
959 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
960 deps_find_witness_calls,
961 deps_find_witness_steps,
962 deps_find_witness_recursions,
963 deps_find_witness_singles);
964 }
965 if (final_stats || (TraceDependencies && WizardMode)) {
966 ttyLocker ttyl;
967 tty->print_cr("Dependency check (find_witness) "
968 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
969 deps_find_witness_calls,
970 deps_find_witness_steps,
971 (double)deps_find_witness_steps / deps_find_witness_calls,
972 deps_find_witness_recursions,
973 deps_find_witness_singles);
974 }
975 }
976 return true;
977 }
978 return false;
979 }
980 #else
981 #define count_find_witness_calls() (0)
982 #endif //PRODUCT
985 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
986 Klass* context_type,
987 bool participants_hide_witnesses) {
988 assert(changes.involves_context(context_type), "irrelevant dependency");
989 Klass* new_type = changes.new_type();
991 count_find_witness_calls();
992 NOT_PRODUCT(deps_find_witness_singles++);
994 // Current thread must be in VM (not native mode, as in CI):
995 assert(must_be_in_vm(), "raw oops here");
996 // Must not move the class hierarchy during this check:
997 assert_locked_or_safepoint(Compile_lock);
999 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1000 if (nof_impls > 1) {
1001 // Avoid this case: *I.m > { A.m, C }; B.m > C
1002 // %%% Until this is fixed more systematically, bail out.
1003 // See corresponding comment in find_witness_anywhere.
1004 return context_type;
1005 }
1007 assert(!is_participant(new_type), "only old classes are participants");
1008 if (participants_hide_witnesses) {
1009 // If the new type is a subtype of a participant, we are done.
1010 for (int i = 0; i < num_participants(); i++) {
1011 Klass* part = participant(i);
1012 if (part == NULL) continue;
1013 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part),
1014 "correct marking of participants, b/c new_type is unique");
1015 if (changes.involves_context(part)) {
1016 // new guy is protected from this check by previous participant
1017 return NULL;
1018 }
1019 }
1020 }
1022 if (is_witness(new_type) &&
1023 !ignore_witness(new_type)) {
1024 return new_type;
1025 }
1027 return NULL;
1028 }
1031 // Walk hierarchy under a context type, looking for unexpected types.
1032 // Do not report participant types, and recursively walk beneath
1033 // them only if participants_hide_witnesses is false.
1034 // If top_level_call is false, skip testing the context type,
1035 // because the caller has already considered it.
1036 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1037 bool participants_hide_witnesses,
1038 bool top_level_call) {
1039 // Current thread must be in VM (not native mode, as in CI):
1040 assert(must_be_in_vm(), "raw oops here");
1041 // Must not move the class hierarchy during this check:
1042 assert_locked_or_safepoint(Compile_lock);
1044 bool do_counts = count_find_witness_calls();
1046 // Check the root of the sub-hierarchy first.
1047 if (top_level_call) {
1048 if (do_counts) {
1049 NOT_PRODUCT(deps_find_witness_calls++);
1050 NOT_PRODUCT(deps_find_witness_steps++);
1051 }
1052 if (is_participant(context_type)) {
1053 if (participants_hide_witnesses) return NULL;
1054 // else fall through to search loop...
1055 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1056 // The context is an abstract class or interface, to start with.
1057 return context_type;
1058 }
1059 }
1061 // Now we must check each implementor and each subclass.
1062 // Use a short worklist to avoid blowing the stack.
1063 // Each worklist entry is a *chain* of subklass siblings to process.
1064 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1065 Klass* chains[CHAINMAX];
1066 int chaini = 0; // index into worklist
1067 Klass* chain; // scratch variable
1068 #define ADD_SUBCLASS_CHAIN(k) { \
1069 assert(chaini < CHAINMAX, "oob"); \
1070 chain = InstanceKlass::cast(k)->subklass(); \
1071 if (chain != NULL) chains[chaini++] = chain; }
1073 // Look for non-abstract subclasses.
1074 // (Note: Interfaces do not have subclasses.)
1075 ADD_SUBCLASS_CHAIN(context_type);
1077 // If it is an interface, search its direct implementors.
1078 // (Their subclasses are additional indirect implementors.
1079 // See InstanceKlass::add_implementor.)
1080 // (Note: nof_implementors is always zero for non-interfaces.)
1081 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1082 if (nof_impls > 1) {
1083 // Avoid this case: *I.m > { A.m, C }; B.m > C
1084 // Here, I.m has 2 concrete implementations, but m appears unique
1085 // as A.m, because the search misses B.m when checking C.
1086 // The inherited method B.m was getting missed by the walker
1087 // when interface 'I' was the starting point.
1088 // %%% Until this is fixed more systematically, bail out.
1089 // (Old CHA had the same limitation.)
1090 return context_type;
1091 }
1092 if (nof_impls > 0) {
1093 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1094 assert(impl != NULL, "just checking");
1095 // If impl is the same as the context_type, then more than one
1096 // implementor has seen. No exact info in this case.
1097 if (impl == context_type) {
1098 return context_type; // report an inexact witness to this sad affair
1099 }
1100 if (do_counts)
1101 { NOT_PRODUCT(deps_find_witness_steps++); }
1102 if (is_participant(impl)) {
1103 if (!participants_hide_witnesses) {
1104 ADD_SUBCLASS_CHAIN(impl);
1105 }
1106 } else if (is_witness(impl) && !ignore_witness(impl)) {
1107 return impl;
1108 } else {
1109 ADD_SUBCLASS_CHAIN(impl);
1110 }
1111 }
1113 // Recursively process each non-trivial sibling chain.
1114 while (chaini > 0) {
1115 Klass* chain = chains[--chaini];
1116 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1117 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1118 if (is_participant(sub)) {
1119 if (participants_hide_witnesses) continue;
1120 // else fall through to process this guy's subclasses
1121 } else if (is_witness(sub) && !ignore_witness(sub)) {
1122 return sub;
1123 }
1124 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1125 // Fast path. (Partially disabled if VerifyDependencies.)
1126 ADD_SUBCLASS_CHAIN(sub);
1127 } else {
1128 // Worklist overflow. Do a recursive call. Should be rare.
1129 // The recursive call will have its own worklist, of course.
1130 // (Note that sub has already been tested, so that there is
1131 // no need for the recursive call to re-test. That's handy,
1132 // since the recursive call sees sub as the context_type.)
1133 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1134 Klass* witness = find_witness_anywhere(sub,
1135 participants_hide_witnesses,
1136 /*top_level_call=*/ false);
1137 if (witness != NULL) return witness;
1138 }
1139 }
1140 }
1142 // No witness found. The dependency remains unbroken.
1143 return NULL;
1144 #undef ADD_SUBCLASS_CHAIN
1145 }
1148 bool Dependencies::is_concrete_klass(Klass* k) {
1149 if (Klass::cast(k)->is_abstract()) return false;
1150 // %%% We could treat classes which are concrete but
1151 // have not yet been instantiated as virtually abstract.
1152 // This would require a deoptimization barrier on first instantiation.
1153 //if (k->is_not_instantiated()) return false;
1154 return true;
1155 }
1157 bool Dependencies::is_concrete_method(Method* m) {
1158 // Statics are irrelevant to virtual call sites.
1159 if (m->is_static()) return false;
1161 // We could also return false if m does not yet appear to be
1162 // executed, if the VM version supports this distinction also.
1163 return !m->is_abstract() &&
1164 !InstanceKlass::cast(m->method_holder())->is_interface();
1165 // TODO: investigate whether default methods should be
1166 // considered as "concrete" in this situation. For now they
1167 // are not.
1168 }
1171 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1172 if (k->is_interface()) return NULL;
1173 if (k->has_finalizer()) return k;
1174 k = k->subklass();
1175 while (k != NULL) {
1176 Klass* result = find_finalizable_subclass(k);
1177 if (result != NULL) return result;
1178 k = k->next_sibling();
1179 }
1180 return NULL;
1181 }
1184 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1185 if (k->is_abstract()) return false;
1186 // We could also return false if k does not yet appear to be
1187 // instantiated, if the VM version supports this distinction also.
1188 //if (k->is_not_instantiated()) return false;
1189 return true;
1190 }
1192 bool Dependencies::is_concrete_method(ciMethod* m) {
1193 // Statics are irrelevant to virtual call sites.
1194 if (m->is_static()) return false;
1196 // We could also return false if m does not yet appear to be
1197 // executed, if the VM version supports this distinction also.
1198 return !m->is_abstract();
1199 }
1202 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1203 return k->has_finalizable_subclass();
1204 }
1207 // Any use of the contents (bytecodes) of a method must be
1208 // marked by an "evol_method" dependency, if those contents
1209 // can change. (Note: A method is always dependent on itself.)
1210 Klass* Dependencies::check_evol_method(Method* m) {
1211 assert(must_be_in_vm(), "raw oops here");
1212 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1213 // Or is there a now a breakpoint?
1214 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1215 if (m->is_old()
1216 || m->number_of_breakpoints() > 0) {
1217 return m->method_holder();
1218 } else {
1219 return NULL;
1220 }
1221 }
1223 // This is a strong assertion: It is that the given type
1224 // has no subtypes whatever. It is most useful for
1225 // optimizing checks on reflected types or on array types.
1226 // (Checks on types which are derived from real instances
1227 // can be optimized more strongly than this, because we
1228 // know that the checked type comes from a concrete type,
1229 // and therefore we can disregard abstract types.)
1230 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1231 assert(must_be_in_vm(), "raw oops here");
1232 assert_locked_or_safepoint(Compile_lock);
1233 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1234 Klass* sub = ctx->subklass();
1235 if (sub != NULL) {
1236 return sub;
1237 } else if (ctx->nof_implementors() != 0) {
1238 // if it is an interface, it must be unimplemented
1239 // (if it is not an interface, nof_implementors is always zero)
1240 Klass* impl = ctx->implementor();
1241 assert(impl != NULL, "must be set");
1242 return impl;
1243 } else {
1244 return NULL;
1245 }
1246 }
1248 // Test the assertion that conck is the only concrete subtype* of ctxk.
1249 // The type conck itself is allowed to have have further concrete subtypes.
1250 // This allows the compiler to narrow occurrences of ctxk by conck,
1251 // when dealing with the types of actual instances.
1252 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1253 Klass* conck,
1254 KlassDepChange* changes) {
1255 ClassHierarchyWalker wf(conck);
1256 return wf.find_witness_subtype(ctxk, changes);
1257 }
1259 // If a non-concrete class has no concrete subtypes, it is not (yet)
1260 // instantiatable. This can allow the compiler to make some paths go
1261 // dead, if they are gated by a test of the type.
1262 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1263 KlassDepChange* changes) {
1264 // Find any concrete subtype, with no participants:
1265 ClassHierarchyWalker wf;
1266 return wf.find_witness_subtype(ctxk, changes);
1267 }
1270 // If a concrete class has no concrete subtypes, it can always be
1271 // exactly typed. This allows the use of a cheaper type test.
1272 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1273 KlassDepChange* changes) {
1274 // Find any concrete subtype, with only the ctxk as participant:
1275 ClassHierarchyWalker wf(ctxk);
1276 return wf.find_witness_subtype(ctxk, changes);
1277 }
1280 // Find the unique concrete proper subtype of ctxk, or NULL if there
1281 // is more than one concrete proper subtype. If there are no concrete
1282 // proper subtypes, return ctxk itself, whether it is concrete or not.
1283 // The returned subtype is allowed to have have further concrete subtypes.
1284 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1285 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1286 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1287 wf.record_witnesses(1); // Record one other witness when walking.
1288 Klass* wit = wf.find_witness_subtype(ctxk);
1289 if (wit != NULL) return NULL; // Too many witnesses.
1290 Klass* conck = wf.participant(0);
1291 if (conck == NULL) {
1292 #ifndef PRODUCT
1293 // Make sure the dependency mechanism will pass this discovery:
1294 if (VerifyDependencies) {
1295 // Turn off dependency tracing while actually testing deps.
1296 FlagSetting fs(TraceDependencies, false);
1297 if (!Dependencies::is_concrete_klass(ctxk)) {
1298 guarantee(NULL ==
1299 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1300 "verify dep.");
1301 } else {
1302 guarantee(NULL ==
1303 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1304 "verify dep.");
1305 }
1306 }
1307 #endif //PRODUCT
1308 return ctxk; // Return ctxk as a flag for "no subtypes".
1309 } else {
1310 #ifndef PRODUCT
1311 // Make sure the dependency mechanism will pass this discovery:
1312 if (VerifyDependencies) {
1313 // Turn off dependency tracing while actually testing deps.
1314 FlagSetting fs(TraceDependencies, false);
1315 if (!Dependencies::is_concrete_klass(ctxk)) {
1316 guarantee(NULL == (void *)
1317 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1318 "verify dep.");
1319 }
1320 }
1321 #endif //PRODUCT
1322 return conck;
1323 }
1324 }
1326 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1327 // except possibly for further subtypes of k[12] themselves.
1328 // The context type must be abstract. The types k1 and k2 are themselves
1329 // allowed to have further concrete subtypes.
1330 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1331 Klass* ctxk,
1332 Klass* k1,
1333 Klass* k2,
1334 KlassDepChange* changes) {
1335 ClassHierarchyWalker wf;
1336 wf.add_participant(k1);
1337 wf.add_participant(k2);
1338 return wf.find_witness_subtype(ctxk, changes);
1339 }
1341 // Search ctxk for concrete implementations. If there are klen or fewer,
1342 // pack them into the given array and return the number.
1343 // Otherwise, return -1, meaning the given array would overflow.
1344 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1345 // In this search, if ctxk is concrete, it will be reported alone.
1346 // For any type CC reported, no proper subtypes of CC will be reported.
1347 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1348 int klen,
1349 Klass* karray[]) {
1350 ClassHierarchyWalker wf;
1351 wf.record_witnesses(klen);
1352 Klass* wit = wf.find_witness_subtype(ctxk);
1353 if (wit != NULL) return -1; // Too many witnesses.
1354 int num = wf.num_participants();
1355 assert(num <= klen, "oob");
1356 // Pack the result array with the good news.
1357 for (int i = 0; i < num; i++)
1358 karray[i] = wf.participant(i);
1359 #ifndef PRODUCT
1360 // Make sure the dependency mechanism will pass this discovery:
1361 if (VerifyDependencies) {
1362 // Turn off dependency tracing while actually testing deps.
1363 FlagSetting fs(TraceDependencies, false);
1364 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1365 case -1: // ctxk was itself concrete
1366 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1367 break;
1368 case 0:
1369 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1370 "verify dep.");
1371 break;
1372 case 1:
1373 guarantee(NULL == (void *)
1374 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1375 "verify dep.");
1376 break;
1377 case 2:
1378 guarantee(NULL == (void *)
1379 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1380 karray[0],
1381 karray[1]),
1382 "verify dep.");
1383 break;
1384 default:
1385 ShouldNotReachHere(); // klen > 2 yet supported
1386 }
1387 }
1388 #endif //PRODUCT
1389 return num;
1390 }
1392 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1393 // Otherwise, return a class that contains an interfering method.
1394 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1395 KlassDepChange* changes) {
1396 // Here is a missing optimization: If uniqm->is_final(),
1397 // we don't really need to search beneath it for overrides.
1398 // This is probably not important, since we don't use dependencies
1399 // to track final methods. (They can't be "definalized".)
1400 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1401 return wf.find_witness_definer(ctxk, changes);
1402 }
1404 // Find the set of all non-abstract methods under ctxk that match m.
1405 // (The method m must be defined or inherited in ctxk.)
1406 // Include m itself in the set, unless it is abstract.
1407 // If this set has exactly one element, return that element.
1408 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1409 ClassHierarchyWalker wf(m);
1410 assert(wf.check_method_context(ctxk, m), "proper context");
1411 wf.record_witnesses(1);
1412 Klass* wit = wf.find_witness_definer(ctxk);
1413 if (wit != NULL) return NULL; // Too many witnesses.
1414 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1415 if (Dependencies::is_concrete_method(m)) {
1416 if (fm == NULL) {
1417 // It turns out that m was always the only implementation.
1418 fm = m;
1419 } else if (fm != m) {
1420 // Two conflicting implementations after all.
1421 // (This can happen if m is inherited into ctxk and fm overrides it.)
1422 return NULL;
1423 }
1424 }
1425 #ifndef PRODUCT
1426 // Make sure the dependency mechanism will pass this discovery:
1427 if (VerifyDependencies && fm != NULL) {
1428 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1429 "verify dep.");
1430 }
1431 #endif //PRODUCT
1432 return fm;
1433 }
1435 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1436 Method* m1,
1437 Method* m2,
1438 KlassDepChange* changes) {
1439 ClassHierarchyWalker wf(m1);
1440 wf.add_participant(m1->method_holder());
1441 wf.add_participant(m2->method_holder());
1442 return wf.find_witness_definer(ctxk, changes);
1443 }
1445 // Find the set of all non-abstract methods under ctxk that match m[0].
1446 // (The method m[0] must be defined or inherited in ctxk.)
1447 // Include m itself in the set, unless it is abstract.
1448 // Fill the given array m[0..(mlen-1)] with this set, and return the length.
1449 // (The length may be zero if no concrete methods are found anywhere.)
1450 // If there are too many concrete methods to fit in marray, return -1.
1451 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk,
1452 int mlen,
1453 Method* marray[]) {
1454 Method* m0 = marray[0];
1455 ClassHierarchyWalker wf(m0);
1456 assert(wf.check_method_context(ctxk, m0), "proper context");
1457 wf.record_witnesses(mlen);
1458 bool participants_hide_witnesses = true;
1459 Klass* wit = wf.find_witness_definer(ctxk);
1460 if (wit != NULL) return -1; // Too many witnesses.
1461 int num = wf.num_participants();
1462 assert(num <= mlen, "oob");
1463 // Keep track of whether m is also part of the result set.
1464 int mfill = 0;
1465 assert(marray[mfill] == m0, "sanity");
1466 if (Dependencies::is_concrete_method(m0))
1467 mfill++; // keep m0 as marray[0], the first result
1468 for (int i = 0; i < num; i++) {
1469 Method* fm = wf.found_method(i);
1470 if (fm == m0) continue; // Already put this guy in the list.
1471 if (mfill == mlen) {
1472 return -1; // Oops. Too many methods after all!
1473 }
1474 marray[mfill++] = fm;
1475 }
1476 #ifndef PRODUCT
1477 // Make sure the dependency mechanism will pass this discovery:
1478 if (VerifyDependencies) {
1479 // Turn off dependency tracing while actually testing deps.
1480 FlagSetting fs(TraceDependencies, false);
1481 switch (mfill) {
1482 case 1:
1483 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
1484 "verify dep.");
1485 break;
1486 case 2:
1487 guarantee(NULL == (void *)
1488 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
1489 "verify dep.");
1490 break;
1491 default:
1492 ShouldNotReachHere(); // mlen > 2 yet supported
1493 }
1494 }
1495 #endif //PRODUCT
1496 return mfill;
1497 }
1500 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1501 Klass* search_at = ctxk;
1502 if (changes != NULL)
1503 search_at = changes->new_type(); // just look at the new bit
1504 return find_finalizable_subclass(search_at);
1505 }
1508 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1509 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1510 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1511 if (changes == NULL) {
1512 // Validate all CallSites
1513 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1514 return call_site->klass(); // assertion failed
1515 } else {
1516 // Validate the given CallSite
1517 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1518 assert(method_handle != changes->method_handle(), "must be");
1519 return call_site->klass(); // assertion failed
1520 }
1521 }
1522 return NULL; // assertion still valid
1523 }
1526 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1527 if (witness != NULL) {
1528 if (TraceDependencies) {
1529 print_dependency(witness, /*verbose=*/ true);
1530 }
1531 // The following is a no-op unless logging is enabled:
1532 log_dependency(witness);
1533 }
1534 }
1537 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1538 assert_locked_or_safepoint(Compile_lock);
1539 Dependencies::check_valid_dependency_type(type());
1541 Klass* witness = NULL;
1542 switch (type()) {
1543 case evol_method:
1544 witness = check_evol_method(method_argument(0));
1545 break;
1546 case leaf_type:
1547 witness = check_leaf_type(context_type());
1548 break;
1549 case abstract_with_unique_concrete_subtype:
1550 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1551 break;
1552 case abstract_with_no_concrete_subtype:
1553 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1554 break;
1555 case concrete_with_no_concrete_subtype:
1556 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1557 break;
1558 case unique_concrete_method:
1559 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1560 break;
1561 case abstract_with_exclusive_concrete_subtypes_2:
1562 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1563 break;
1564 case exclusive_concrete_methods_2:
1565 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1566 break;
1567 case no_finalizable_subclasses:
1568 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1569 break;
1570 default:
1571 witness = NULL;
1572 break;
1573 }
1574 trace_and_log_witness(witness);
1575 return witness;
1576 }
1579 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1580 assert_locked_or_safepoint(Compile_lock);
1581 Dependencies::check_valid_dependency_type(type());
1583 Klass* witness = NULL;
1584 switch (type()) {
1585 case call_site_target_value:
1586 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1587 break;
1588 default:
1589 witness = NULL;
1590 break;
1591 }
1592 trace_and_log_witness(witness);
1593 return witness;
1594 }
1597 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1598 // Handle klass dependency
1599 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1600 return check_klass_dependency(changes.as_klass_change());
1602 // Handle CallSite dependency
1603 if (changes.is_call_site_change())
1604 return check_call_site_dependency(changes.as_call_site_change());
1606 // irrelevant dependency; skip it
1607 return NULL;
1608 }
1611 void DepChange::print() {
1612 int nsup = 0, nint = 0;
1613 for (ContextStream str(*this); str.next(); ) {
1614 Klass* k = str.klass();
1615 switch (str.change_type()) {
1616 case Change_new_type:
1617 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1618 break;
1619 case Change_new_sub:
1620 if (!WizardMode) {
1621 ++nsup;
1622 } else {
1623 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1624 }
1625 break;
1626 case Change_new_impl:
1627 if (!WizardMode) {
1628 ++nint;
1629 } else {
1630 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1631 }
1632 break;
1633 }
1634 }
1635 if (nsup + nint != 0) {
1636 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1637 }
1638 }
1640 void DepChange::ContextStream::start() {
1641 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1642 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1643 _klass = new_type;
1644 _ti_base = NULL;
1645 _ti_index = 0;
1646 _ti_limit = 0;
1647 }
1649 bool DepChange::ContextStream::next() {
1650 switch (_change_type) {
1651 case Start_Klass: // initial state; _klass is the new type
1652 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1653 _ti_index = 0;
1654 _change_type = Change_new_type;
1655 return true;
1656 case Change_new_type:
1657 // fall through:
1658 _change_type = Change_new_sub;
1659 case Change_new_sub:
1660 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1661 {
1662 _klass = InstanceKlass::cast(_klass)->super();
1663 if (_klass != NULL) {
1664 return true;
1665 }
1666 }
1667 // else set up _ti_limit and fall through:
1668 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1669 _change_type = Change_new_impl;
1670 case Change_new_impl:
1671 if (_ti_index < _ti_limit) {
1672 _klass = _ti_base->at(_ti_index++);
1673 return true;
1674 }
1675 // fall through:
1676 _change_type = NO_CHANGE; // iterator is exhausted
1677 case NO_CHANGE:
1678 break;
1679 default:
1680 ShouldNotReachHere();
1681 }
1682 return false;
1683 }
1685 void KlassDepChange::initialize() {
1686 // entire transaction must be under this lock:
1687 assert_lock_strong(Compile_lock);
1689 // Mark all dependee and all its superclasses
1690 // Mark transitive interfaces
1691 for (ContextStream str(*this); str.next(); ) {
1692 Klass* d = str.klass();
1693 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1694 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1695 }
1696 }
1698 KlassDepChange::~KlassDepChange() {
1699 // Unmark all dependee and all its superclasses
1700 // Unmark transitive interfaces
1701 for (ContextStream str(*this); str.next(); ) {
1702 Klass* d = str.klass();
1703 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1704 }
1705 }
1707 bool KlassDepChange::involves_context(Klass* k) {
1708 if (k == NULL || !Klass::cast(k)->oop_is_instance()) {
1709 return false;
1710 }
1711 InstanceKlass* ik = InstanceKlass::cast(k);
1712 bool is_contained = ik->is_marked_dependent();
1713 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k),
1714 "correct marking of potential context types");
1715 return is_contained;
1716 }
1718 #ifndef PRODUCT
1719 void Dependencies::print_statistics() {
1720 if (deps_find_witness_print != 0) {
1721 // Call one final time, to flush out the data.
1722 deps_find_witness_print = -1;
1723 count_find_witness_calls();
1724 }
1725 }
1726 #endif