Mon, 01 Dec 2014 13:06:20 -0500
8064524: Compiler code generation improvements
Reviewed-by: jrose, acorn, vlivanov
1 /*
2 * Copyright (c) 2005, 2014, 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 "runtime/thread.inline.hpp"
36 #include "utilities/copy.hpp"
39 #ifdef ASSERT
40 static bool must_be_in_vm() {
41 Thread* thread = Thread::current();
42 if (thread->is_Java_thread())
43 return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
44 else
45 return true; //something like this: thread->is_VM_thread();
46 }
47 #endif //ASSERT
49 void Dependencies::initialize(ciEnv* env) {
50 Arena* arena = env->arena();
51 _oop_recorder = env->oop_recorder();
52 _log = env->log();
53 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
54 DEBUG_ONLY(_deps[end_marker] = NULL);
55 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
56 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
57 }
58 _content_bytes = NULL;
59 _size_in_bytes = (size_t)-1;
61 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
62 }
64 void Dependencies::assert_evol_method(ciMethod* m) {
65 assert_common_1(evol_method, m);
66 }
68 void Dependencies::assert_leaf_type(ciKlass* ctxk) {
69 if (ctxk->is_array_klass()) {
70 // As a special case, support this assertion on an array type,
71 // which reduces to an assertion on its element type.
72 // Note that this cannot be done with assertions that
73 // relate to concreteness or abstractness.
74 ciType* elemt = ctxk->as_array_klass()->base_element_type();
75 if (!elemt->is_instance_klass()) return; // Ex: int[][]
76 ctxk = elemt->as_instance_klass();
77 //if (ctxk->is_final()) return; // Ex: String[][]
78 }
79 check_ctxk(ctxk);
80 assert_common_1(leaf_type, ctxk);
81 }
83 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
84 check_ctxk_abstract(ctxk);
85 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
86 }
88 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
89 check_ctxk_abstract(ctxk);
90 assert_common_1(abstract_with_no_concrete_subtype, ctxk);
91 }
93 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
94 check_ctxk_concrete(ctxk);
95 assert_common_1(concrete_with_no_concrete_subtype, ctxk);
96 }
98 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
99 check_ctxk(ctxk);
100 assert_common_2(unique_concrete_method, ctxk, uniqm);
101 }
103 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
104 check_ctxk(ctxk);
105 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
106 }
108 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
109 check_ctxk(ctxk);
110 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
111 }
113 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
114 check_ctxk(ctxk);
115 assert_common_1(no_finalizable_subclasses, ctxk);
116 }
118 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
119 check_ctxk(call_site->klass());
120 assert_common_2(call_site_target_value, call_site, method_handle);
121 }
123 // Helper function. If we are adding a new dep. under ctxk2,
124 // try to find an old dep. under a broader* ctxk1. If there is
125 //
126 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
127 int ctxk_i, ciKlass* ctxk2) {
128 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
129 if (ctxk2->is_subtype_of(ctxk1)) {
130 return true; // success, and no need to change
131 } else if (ctxk1->is_subtype_of(ctxk2)) {
132 // new context class fully subsumes previous one
133 deps->at_put(ctxk_i, ctxk2);
134 return true;
135 } else {
136 return false;
137 }
138 }
140 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
141 assert(dep_args(dept) == 1, "sanity");
142 log_dependency(dept, x);
143 GrowableArray<ciBaseObject*>* deps = _deps[dept];
145 // see if the same (or a similar) dep is already recorded
146 if (note_dep_seen(dept, x)) {
147 assert(deps->find(x) >= 0, "sanity");
148 } else {
149 deps->append(x);
150 }
151 }
153 void Dependencies::assert_common_2(DepType dept,
154 ciBaseObject* x0, ciBaseObject* x1) {
155 assert(dep_args(dept) == 2, "sanity");
156 log_dependency(dept, x0, x1);
157 GrowableArray<ciBaseObject*>* deps = _deps[dept];
159 // see if the same (or a similar) dep is already recorded
160 bool has_ctxk = has_explicit_context_arg(dept);
161 if (has_ctxk) {
162 assert(dep_context_arg(dept) == 0, "sanity");
163 if (note_dep_seen(dept, x1)) {
164 // look in this bucket for redundant assertions
165 const int stride = 2;
166 for (int i = deps->length(); (i -= stride) >= 0; ) {
167 ciBaseObject* y1 = deps->at(i+1);
168 if (x1 == y1) { // same subject; check the context
169 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
170 return;
171 }
172 }
173 }
174 }
175 } else {
176 assert(dep_implicit_context_arg(dept) == 0, "sanity");
177 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
178 // look in this bucket for redundant assertions
179 const int stride = 2;
180 for (int i = deps->length(); (i -= stride) >= 0; ) {
181 ciBaseObject* y0 = deps->at(i+0);
182 ciBaseObject* y1 = deps->at(i+1);
183 if (x0 == y0 && x1 == y1) {
184 return;
185 }
186 }
187 }
188 }
190 // append the assertion in the correct bucket:
191 deps->append(x0);
192 deps->append(x1);
193 }
195 void Dependencies::assert_common_3(DepType dept,
196 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
197 assert(dep_context_arg(dept) == 0, "sanity");
198 assert(dep_args(dept) == 3, "sanity");
199 log_dependency(dept, ctxk, x, x2);
200 GrowableArray<ciBaseObject*>* deps = _deps[dept];
202 // try to normalize an unordered pair:
203 bool swap = false;
204 switch (dept) {
205 case abstract_with_exclusive_concrete_subtypes_2:
206 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
207 break;
208 case exclusive_concrete_methods_2:
209 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
210 break;
211 }
212 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
214 // see if the same (or a similar) dep is already recorded
215 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
216 // look in this bucket for redundant assertions
217 const int stride = 3;
218 for (int i = deps->length(); (i -= stride) >= 0; ) {
219 ciBaseObject* y = deps->at(i+1);
220 ciBaseObject* y2 = deps->at(i+2);
221 if (x == y && x2 == y2) { // same subjects; check the context
222 if (maybe_merge_ctxk(deps, i+0, ctxk)) {
223 return;
224 }
225 }
226 }
227 }
228 // append the assertion in the correct bucket:
229 deps->append(ctxk);
230 deps->append(x);
231 deps->append(x2);
232 }
234 /// Support for encoding dependencies into an nmethod:
236 void Dependencies::copy_to(nmethod* nm) {
237 address beg = nm->dependencies_begin();
238 address end = nm->dependencies_end();
239 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
240 Copy::disjoint_words((HeapWord*) content_bytes(),
241 (HeapWord*) beg,
242 size_in_bytes() / sizeof(HeapWord));
243 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
244 }
246 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
247 for (int i = 0; i < narg; i++) {
248 int diff = p1[i]->ident() - p2[i]->ident();
249 if (diff != 0) return diff;
250 }
251 return 0;
252 }
253 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
254 { return sort_dep(p1, p2, 1); }
255 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
256 { return sort_dep(p1, p2, 2); }
257 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
258 { return sort_dep(p1, p2, 3); }
260 void Dependencies::sort_all_deps() {
261 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
262 DepType dept = (DepType)deptv;
263 GrowableArray<ciBaseObject*>* deps = _deps[dept];
264 if (deps->length() <= 1) continue;
265 switch (dep_args(dept)) {
266 case 1: deps->sort(sort_dep_arg_1, 1); break;
267 case 2: deps->sort(sort_dep_arg_2, 2); break;
268 case 3: deps->sort(sort_dep_arg_3, 3); break;
269 default: ShouldNotReachHere();
270 }
271 }
272 }
274 size_t Dependencies::estimate_size_in_bytes() {
275 size_t est_size = 100;
276 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
277 DepType dept = (DepType)deptv;
278 GrowableArray<ciBaseObject*>* deps = _deps[dept];
279 est_size += deps->length()*2; // tags and argument(s)
280 }
281 return est_size;
282 }
284 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
285 switch (dept) {
286 case abstract_with_exclusive_concrete_subtypes_2:
287 return x->as_metadata()->as_klass();
288 case unique_concrete_method:
289 case exclusive_concrete_methods_2:
290 return x->as_metadata()->as_method()->holder();
291 }
292 return NULL; // let NULL be NULL
293 }
295 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
296 assert(must_be_in_vm(), "raw oops here");
297 switch (dept) {
298 case abstract_with_exclusive_concrete_subtypes_2:
299 assert(x->is_klass(), "sanity");
300 return (Klass*) x;
301 case unique_concrete_method:
302 case exclusive_concrete_methods_2:
303 assert(x->is_method(), "sanity");
304 return ((Method*)x)->method_holder();
305 }
306 return NULL; // let NULL be NULL
307 }
309 void Dependencies::encode_content_bytes() {
310 sort_all_deps();
312 // cast is safe, no deps can overflow INT_MAX
313 CompressedWriteStream bytes((int)estimate_size_in_bytes());
315 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
316 DepType dept = (DepType)deptv;
317 GrowableArray<ciBaseObject*>* deps = _deps[dept];
318 if (deps->length() == 0) continue;
319 int stride = dep_args(dept);
320 int ctxkj = dep_context_arg(dept); // -1 if no context arg
321 assert(stride > 0, "sanity");
322 for (int i = 0; i < deps->length(); i += stride) {
323 jbyte code_byte = (jbyte)dept;
324 int skipj = -1;
325 if (ctxkj >= 0 && ctxkj+1 < stride) {
326 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
327 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
328 if (ctxk == ctxk_encoded_as_null(dept, x)) {
329 skipj = ctxkj; // we win: maybe one less oop to keep track of
330 code_byte |= default_context_type_bit;
331 }
332 }
333 bytes.write_byte(code_byte);
334 for (int j = 0; j < stride; j++) {
335 if (j == skipj) continue;
336 ciBaseObject* v = deps->at(i+j);
337 int idx;
338 if (v->is_object()) {
339 idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
340 } else {
341 ciMetadata* meta = v->as_metadata();
342 idx = _oop_recorder->find_index(meta->constant_encoding());
343 }
344 bytes.write_int(idx);
345 }
346 }
347 }
349 // write a sentinel byte to mark the end
350 bytes.write_byte(end_marker);
352 // round it out to a word boundary
353 while (bytes.position() % sizeof(HeapWord) != 0) {
354 bytes.write_byte(end_marker);
355 }
357 // check whether the dept byte encoding really works
358 assert((jbyte)default_context_type_bit != 0, "byte overflow");
360 _content_bytes = bytes.buffer();
361 _size_in_bytes = bytes.position();
362 }
365 const char* Dependencies::_dep_name[TYPE_LIMIT] = {
366 "end_marker",
367 "evol_method",
368 "leaf_type",
369 "abstract_with_unique_concrete_subtype",
370 "abstract_with_no_concrete_subtype",
371 "concrete_with_no_concrete_subtype",
372 "unique_concrete_method",
373 "abstract_with_exclusive_concrete_subtypes_2",
374 "exclusive_concrete_methods_2",
375 "no_finalizable_subclasses",
376 "call_site_target_value"
377 };
379 int Dependencies::_dep_args[TYPE_LIMIT] = {
380 -1,// end_marker
381 1, // evol_method m
382 1, // leaf_type ctxk
383 2, // abstract_with_unique_concrete_subtype ctxk, k
384 1, // abstract_with_no_concrete_subtype ctxk
385 1, // concrete_with_no_concrete_subtype ctxk
386 2, // unique_concrete_method ctxk, m
387 3, // unique_concrete_subtypes_2 ctxk, k1, k2
388 3, // unique_concrete_methods_2 ctxk, m1, m2
389 1, // no_finalizable_subclasses ctxk
390 2 // call_site_target_value call_site, method_handle
391 };
393 const char* Dependencies::dep_name(Dependencies::DepType dept) {
394 if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
395 return _dep_name[dept];
396 }
398 int Dependencies::dep_args(Dependencies::DepType dept) {
399 if (!dept_in_mask(dept, all_types)) return -1;
400 return _dep_args[dept];
401 }
403 void Dependencies::check_valid_dependency_type(DepType dept) {
404 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept));
405 }
407 // for the sake of the compiler log, print out current dependencies:
408 void Dependencies::log_all_dependencies() {
409 if (log() == NULL) return;
410 ResourceMark rm;
411 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
412 DepType dept = (DepType)deptv;
413 GrowableArray<ciBaseObject*>* deps = _deps[dept];
414 int deplen = deps->length();
415 if (deplen == 0) {
416 continue;
417 }
418 int stride = dep_args(dept);
419 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
420 for (int i = 0; i < deps->length(); i += stride) {
421 for (int j = 0; j < stride; j++) {
422 // flush out the identities before printing
423 ciargs->push(deps->at(i+j));
424 }
425 write_dependency_to(log(), dept, ciargs);
426 ciargs->clear();
427 }
428 guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
429 }
430 }
432 void Dependencies::write_dependency_to(CompileLog* log,
433 DepType dept,
434 GrowableArray<DepArgument>* args,
435 Klass* witness) {
436 if (log == NULL) {
437 return;
438 }
439 ResourceMark rm;
440 ciEnv* env = ciEnv::current();
441 GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
442 for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
443 DepArgument arg = *it;
444 if (arg.is_oop()) {
445 ciargs->push(env->get_object(arg.oop_value()));
446 } else {
447 ciargs->push(env->get_metadata(arg.metadata_value()));
448 }
449 }
450 int argslen = ciargs->length();
451 Dependencies::write_dependency_to(log, dept, ciargs, witness);
452 guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
453 }
455 void Dependencies::write_dependency_to(CompileLog* log,
456 DepType dept,
457 GrowableArray<ciBaseObject*>* args,
458 Klass* witness) {
459 if (log == NULL) {
460 return;
461 }
462 ResourceMark rm;
463 GrowableArray<int>* argids = new GrowableArray<int>(args->length());
464 for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
465 ciBaseObject* obj = *it;
466 if (obj->is_object()) {
467 argids->push(log->identify(obj->as_object()));
468 } else {
469 argids->push(log->identify(obj->as_metadata()));
470 }
471 }
472 if (witness != NULL) {
473 log->begin_elem("dependency_failed");
474 } else {
475 log->begin_elem("dependency");
476 }
477 log->print(" type='%s'", dep_name(dept));
478 const int ctxkj = dep_context_arg(dept); // -1 if no context arg
479 if (ctxkj >= 0 && ctxkj < argids->length()) {
480 log->print(" ctxk='%d'", argids->at(ctxkj));
481 }
482 // write remaining arguments, if any.
483 for (int j = 0; j < argids->length(); j++) {
484 if (j == ctxkj) continue; // already logged
485 if (j == 1) {
486 log->print( " x='%d'", argids->at(j));
487 } else {
488 log->print(" x%d='%d'", j, argids->at(j));
489 }
490 }
491 if (witness != NULL) {
492 log->object("witness", witness);
493 log->stamp();
494 }
495 log->end_elem();
496 }
498 void Dependencies::write_dependency_to(xmlStream* xtty,
499 DepType dept,
500 GrowableArray<DepArgument>* args,
501 Klass* witness) {
502 if (xtty == NULL) {
503 return;
504 }
505 ResourceMark rm;
506 ttyLocker ttyl;
507 int ctxkj = dep_context_arg(dept); // -1 if no context arg
508 if (witness != NULL) {
509 xtty->begin_elem("dependency_failed");
510 } else {
511 xtty->begin_elem("dependency");
512 }
513 xtty->print(" type='%s'", dep_name(dept));
514 if (ctxkj >= 0) {
515 xtty->object("ctxk", args->at(ctxkj).metadata_value());
516 }
517 // write remaining arguments, if any.
518 for (int j = 0; j < args->length(); j++) {
519 if (j == ctxkj) continue; // already logged
520 DepArgument arg = args->at(j);
521 if (j == 1) {
522 if (arg.is_oop()) {
523 xtty->object("x", arg.oop_value());
524 } else {
525 xtty->object("x", arg.metadata_value());
526 }
527 } else {
528 char xn[10]; sprintf(xn, "x%d", j);
529 if (arg.is_oop()) {
530 xtty->object(xn, arg.oop_value());
531 } else {
532 xtty->object(xn, arg.metadata_value());
533 }
534 }
535 }
536 if (witness != NULL) {
537 xtty->object("witness", witness);
538 xtty->stamp();
539 }
540 xtty->end_elem();
541 }
543 void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
544 Klass* witness) {
545 ResourceMark rm;
546 ttyLocker ttyl; // keep the following output all in one block
547 tty->print_cr("%s of type %s",
548 (witness == NULL)? "Dependency": "Failed dependency",
549 dep_name(dept));
550 // print arguments
551 int ctxkj = dep_context_arg(dept); // -1 if no context arg
552 for (int j = 0; j < args->length(); j++) {
553 DepArgument arg = args->at(j);
554 bool put_star = false;
555 if (arg.is_null()) continue;
556 const char* what;
557 if (j == ctxkj) {
558 assert(arg.is_metadata(), "must be");
559 what = "context";
560 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
561 } else if (arg.is_method()) {
562 what = "method ";
563 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value(), NULL);
564 } else if (arg.is_klass()) {
565 what = "class ";
566 } else {
567 what = "object ";
568 }
569 tty->print(" %s = %s", what, (put_star? "*": ""));
570 if (arg.is_klass())
571 tty->print("%s", ((Klass*)arg.metadata_value())->external_name());
572 else if (arg.is_method())
573 ((Method*)arg.metadata_value())->print_value();
574 else
575 ShouldNotReachHere(); // Provide impl for this type.
576 tty->cr();
577 }
578 if (witness != NULL) {
579 bool put_star = !Dependencies::is_concrete_klass(witness);
580 tty->print_cr(" witness = %s%s",
581 (put_star? "*": ""),
582 witness->external_name());
583 }
584 }
586 void Dependencies::DepStream::log_dependency(Klass* witness) {
587 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
588 ResourceMark rm;
589 const int nargs = argument_count();
590 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
591 for (int j = 0; j < nargs; j++) {
592 if (type() == call_site_target_value) {
593 args->push(argument_oop(j));
594 } else {
595 args->push(argument(j));
596 }
597 }
598 int argslen = args->length();
599 if (_deps != NULL && _deps->log() != NULL) {
600 Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
601 } else {
602 Dependencies::write_dependency_to(xtty, type(), args, witness);
603 }
604 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
605 }
607 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) {
608 ResourceMark rm;
609 int nargs = argument_count();
610 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
611 for (int j = 0; j < nargs; j++) {
612 args->push(argument(j));
613 }
614 int argslen = args->length();
615 Dependencies::print_dependency(type(), args, witness);
616 if (verbose) {
617 if (_code != NULL) {
618 tty->print(" code: ");
619 _code->print_value_on(tty);
620 tty->cr();
621 }
622 }
623 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
624 }
627 /// Dependency stream support (decodes dependencies from an nmethod):
629 #ifdef ASSERT
630 void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
631 assert(must_be_in_vm(), "raw oops here");
632 _byte_limit = byte_limit;
633 _type = (DepType)(end_marker-1); // defeat "already at end" assert
634 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
635 }
636 #endif //ASSERT
638 bool Dependencies::DepStream::next() {
639 assert(_type != end_marker, "already at end");
640 if (_bytes.position() == 0 && _code != NULL
641 && _code->dependencies_size() == 0) {
642 // Method has no dependencies at all.
643 return false;
644 }
645 int code_byte = (_bytes.read_byte() & 0xFF);
646 if (code_byte == end_marker) {
647 DEBUG_ONLY(_type = end_marker);
648 return false;
649 } else {
650 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
651 code_byte -= ctxk_bit;
652 DepType dept = (DepType)code_byte;
653 _type = dept;
654 Dependencies::check_valid_dependency_type(dept);
655 int stride = _dep_args[dept];
656 assert(stride == dep_args(dept), "sanity");
657 int skipj = -1;
658 if (ctxk_bit != 0) {
659 skipj = 0; // currently the only context argument is at zero
660 assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
661 }
662 for (int j = 0; j < stride; j++) {
663 _xi[j] = (j == skipj)? 0: _bytes.read_int();
664 }
665 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
666 return true;
667 }
668 }
670 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
671 Metadata* o = NULL;
672 if (_code != NULL) {
673 o = _code->metadata_at(i);
674 } else {
675 o = _deps->oop_recorder()->metadata_at(i);
676 }
677 return o;
678 }
680 inline oop Dependencies::DepStream::recorded_oop_at(int i) {
681 return (_code != NULL)
682 ? _code->oop_at(i)
683 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
684 }
686 Metadata* Dependencies::DepStream::argument(int i) {
687 Metadata* result = recorded_metadata_at(argument_index(i));
689 if (result == NULL) { // Explicit context argument can be compressed
690 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
691 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
692 result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
693 }
694 }
696 assert(result == NULL || result->is_klass() || result->is_method(), "must be");
697 return result;
698 }
700 oop Dependencies::DepStream::argument_oop(int i) {
701 oop result = recorded_oop_at(argument_index(i));
702 assert(result == NULL || result->is_oop(), "must be");
703 return result;
704 }
706 Klass* Dependencies::DepStream::context_type() {
707 assert(must_be_in_vm(), "raw oops here");
709 // Most dependencies have an explicit context type argument.
710 {
711 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
712 if (ctxkj >= 0) {
713 Metadata* k = argument(ctxkj);
714 assert(k != NULL && k->is_klass(), "type check");
715 return (Klass*)k;
716 }
717 }
719 // Some dependencies are using the klass of the first object
720 // argument as implicit context type (e.g. call_site_target_value).
721 {
722 int ctxkj = dep_implicit_context_arg(type());
723 if (ctxkj >= 0) {
724 Klass* k = argument_oop(ctxkj)->klass();
725 assert(k != NULL && k->is_klass(), "type check");
726 return (Klass*) k;
727 }
728 }
730 // And some dependencies don't have a context type at all,
731 // e.g. evol_method.
732 return NULL;
733 }
735 /// Checking dependencies:
737 // This hierarchy walker inspects subtypes of a given type,
738 // trying to find a "bad" class which breaks a dependency.
739 // Such a class is called a "witness" to the broken dependency.
740 // While searching around, we ignore "participants", which
741 // are already known to the dependency.
742 class ClassHierarchyWalker {
743 public:
744 enum { PARTICIPANT_LIMIT = 3 };
746 private:
747 // optional method descriptor to check for:
748 Symbol* _name;
749 Symbol* _signature;
751 // special classes which are not allowed to be witnesses:
752 Klass* _participants[PARTICIPANT_LIMIT+1];
753 int _num_participants;
755 // cache of method lookups
756 Method* _found_methods[PARTICIPANT_LIMIT+1];
758 // if non-zero, tells how many witnesses to convert to participants
759 int _record_witnesses;
761 void initialize(Klass* participant) {
762 _record_witnesses = 0;
763 _participants[0] = participant;
764 _found_methods[0] = NULL;
765 _num_participants = 0;
766 if (participant != NULL) {
767 // Terminating NULL.
768 _participants[1] = NULL;
769 _found_methods[1] = NULL;
770 _num_participants = 1;
771 }
772 }
774 void initialize_from_method(Method* m) {
775 assert(m != NULL && m->is_method(), "sanity");
776 _name = m->name();
777 _signature = m->signature();
778 }
780 public:
781 // The walker is initialized to recognize certain methods and/or types
782 // as friendly participants.
783 ClassHierarchyWalker(Klass* participant, Method* m) {
784 initialize_from_method(m);
785 initialize(participant);
786 }
787 ClassHierarchyWalker(Method* m) {
788 initialize_from_method(m);
789 initialize(NULL);
790 }
791 ClassHierarchyWalker(Klass* participant = NULL) {
792 _name = NULL;
793 _signature = NULL;
794 initialize(participant);
795 }
797 // This is common code for two searches: One for concrete subtypes,
798 // the other for concrete method implementations and overrides.
799 bool doing_subtype_search() {
800 return _name == NULL;
801 }
803 int num_participants() { return _num_participants; }
804 Klass* participant(int n) {
805 assert((uint)n <= (uint)_num_participants, "oob");
806 return _participants[n];
807 }
809 // Note: If n==num_participants, returns NULL.
810 Method* found_method(int n) {
811 assert((uint)n <= (uint)_num_participants, "oob");
812 Method* fm = _found_methods[n];
813 assert(n == _num_participants || fm != NULL, "proper usage");
814 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
815 return fm;
816 }
818 #ifdef ASSERT
819 // Assert that m is inherited into ctxk, without intervening overrides.
820 // (May return true even if this is not true, in corner cases where we punt.)
821 bool check_method_context(Klass* ctxk, Method* m) {
822 if (m->method_holder() == ctxk)
823 return true; // Quick win.
824 if (m->is_private())
825 return false; // Quick lose. Should not happen.
826 if (!(m->is_public() || m->is_protected()))
827 // The override story is complex when packages get involved.
828 return true; // Must punt the assertion to true.
829 Klass* k = ctxk;
830 Method* lm = k->lookup_method(m->name(), m->signature());
831 if (lm == NULL && k->oop_is_instance()) {
832 // It might be an interface method
833 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(),
834 m->signature());
835 }
836 if (lm == m)
837 // Method m is inherited into ctxk.
838 return true;
839 if (lm != NULL) {
840 if (!(lm->is_public() || lm->is_protected())) {
841 // Method is [package-]private, so the override story is complex.
842 return true; // Must punt the assertion to true.
843 }
844 if (lm->is_static()) {
845 // Static methods don't override non-static so punt
846 return true;
847 }
848 if ( !Dependencies::is_concrete_method(lm, k)
849 && !Dependencies::is_concrete_method(m, ctxk)
850 && lm->method_holder()->is_subtype_of(m->method_holder()))
851 // Method m is overridden by lm, but both are non-concrete.
852 return true;
853 }
854 ResourceMark rm;
855 tty->print_cr("Dependency method not found in the associated context:");
856 tty->print_cr(" context = %s", ctxk->external_name());
857 tty->print( " method = "); m->print_short_name(tty); tty->cr();
858 if (lm != NULL) {
859 tty->print( " found = "); lm->print_short_name(tty); tty->cr();
860 }
861 return false;
862 }
863 #endif
865 void add_participant(Klass* participant) {
866 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
867 int np = _num_participants++;
868 _participants[np] = participant;
869 _participants[np+1] = NULL;
870 _found_methods[np+1] = NULL;
871 }
873 void record_witnesses(int add) {
874 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
875 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
876 _record_witnesses = add;
877 }
879 bool is_witness(Klass* k) {
880 if (doing_subtype_search()) {
881 return Dependencies::is_concrete_klass(k);
882 } else {
883 // Search class hierarchy first.
884 Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature);
885 if (!Dependencies::is_concrete_method(m, k)) {
886 // Check interface defaults also, if any exist.
887 Array<Method*>* default_methods = InstanceKlass::cast(k)->default_methods();
888 if (default_methods == NULL)
889 return false;
890 m = InstanceKlass::cast(k)->find_method(default_methods, _name, _signature);
891 if (!Dependencies::is_concrete_method(m, NULL))
892 return false;
893 }
894 _found_methods[_num_participants] = m;
895 // Note: If add_participant(k) is called,
896 // the method m will already be memoized for it.
897 return true;
898 }
899 }
901 bool is_participant(Klass* k) {
902 if (k == _participants[0]) {
903 return true;
904 } else if (_num_participants <= 1) {
905 return false;
906 } else {
907 return in_list(k, &_participants[1]);
908 }
909 }
910 bool ignore_witness(Klass* witness) {
911 if (_record_witnesses == 0) {
912 return false;
913 } else {
914 --_record_witnesses;
915 add_participant(witness);
916 return true;
917 }
918 }
919 static bool in_list(Klass* x, Klass** list) {
920 for (int i = 0; ; i++) {
921 Klass* y = list[i];
922 if (y == NULL) break;
923 if (y == x) return true;
924 }
925 return false; // not in list
926 }
928 private:
929 // the actual search method:
930 Klass* find_witness_anywhere(Klass* context_type,
931 bool participants_hide_witnesses,
932 bool top_level_call = true);
933 // the spot-checking version:
934 Klass* find_witness_in(KlassDepChange& changes,
935 Klass* context_type,
936 bool participants_hide_witnesses);
937 public:
938 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
939 assert(doing_subtype_search(), "must set up a subtype search");
940 // When looking for unexpected concrete types,
941 // do not look beneath expected ones.
942 const bool participants_hide_witnesses = true;
943 // CX > CC > C' is OK, even if C' is new.
944 // CX > { CC, C' } is not OK if C' is new, and C' is the witness.
945 if (changes != NULL) {
946 return find_witness_in(*changes, context_type, participants_hide_witnesses);
947 } else {
948 return find_witness_anywhere(context_type, participants_hide_witnesses);
949 }
950 }
951 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
952 assert(!doing_subtype_search(), "must set up a method definer search");
953 // When looking for unexpected concrete methods,
954 // look beneath expected ones, to see if there are overrides.
955 const bool participants_hide_witnesses = true;
956 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
957 if (changes != NULL) {
958 return find_witness_in(*changes, context_type, !participants_hide_witnesses);
959 } else {
960 return find_witness_anywhere(context_type, !participants_hide_witnesses);
961 }
962 }
963 };
965 #ifndef PRODUCT
966 static int deps_find_witness_calls = 0;
967 static int deps_find_witness_steps = 0;
968 static int deps_find_witness_recursions = 0;
969 static int deps_find_witness_singles = 0;
970 static int deps_find_witness_print = 0; // set to -1 to force a final print
971 static bool count_find_witness_calls() {
972 if (TraceDependencies || LogCompilation) {
973 int pcount = deps_find_witness_print + 1;
974 bool final_stats = (pcount == 0);
975 bool initial_call = (pcount == 1);
976 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
977 if (pcount < 0) pcount = 1; // crude overflow protection
978 deps_find_witness_print = pcount;
979 if (VerifyDependencies && initial_call) {
980 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
981 }
982 if (occasional_print || final_stats) {
983 // Every now and then dump a little info about dependency searching.
984 if (xtty != NULL) {
985 ttyLocker ttyl;
986 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
987 deps_find_witness_calls,
988 deps_find_witness_steps,
989 deps_find_witness_recursions,
990 deps_find_witness_singles);
991 }
992 if (final_stats || (TraceDependencies && WizardMode)) {
993 ttyLocker ttyl;
994 tty->print_cr("Dependency check (find_witness) "
995 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
996 deps_find_witness_calls,
997 deps_find_witness_steps,
998 (double)deps_find_witness_steps / deps_find_witness_calls,
999 deps_find_witness_recursions,
1000 deps_find_witness_singles);
1001 }
1002 }
1003 return true;
1004 }
1005 return false;
1006 }
1007 #else
1008 #define count_find_witness_calls() (0)
1009 #endif //PRODUCT
1012 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
1013 Klass* context_type,
1014 bool participants_hide_witnesses) {
1015 assert(changes.involves_context(context_type), "irrelevant dependency");
1016 Klass* new_type = changes.new_type();
1018 (void)count_find_witness_calls();
1019 NOT_PRODUCT(deps_find_witness_singles++);
1021 // Current thread must be in VM (not native mode, as in CI):
1022 assert(must_be_in_vm(), "raw oops here");
1023 // Must not move the class hierarchy during this check:
1024 assert_locked_or_safepoint(Compile_lock);
1026 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1027 if (nof_impls > 1) {
1028 // Avoid this case: *I.m > { A.m, C }; B.m > C
1029 // %%% Until this is fixed more systematically, bail out.
1030 // See corresponding comment in find_witness_anywhere.
1031 return context_type;
1032 }
1034 assert(!is_participant(new_type), "only old classes are participants");
1035 if (participants_hide_witnesses) {
1036 // If the new type is a subtype of a participant, we are done.
1037 for (int i = 0; i < num_participants(); i++) {
1038 Klass* part = participant(i);
1039 if (part == NULL) continue;
1040 assert(changes.involves_context(part) == new_type->is_subtype_of(part),
1041 "correct marking of participants, b/c new_type is unique");
1042 if (changes.involves_context(part)) {
1043 // new guy is protected from this check by previous participant
1044 return NULL;
1045 }
1046 }
1047 }
1049 if (is_witness(new_type) &&
1050 !ignore_witness(new_type)) {
1051 return new_type;
1052 }
1054 return NULL;
1055 }
1058 // Walk hierarchy under a context type, looking for unexpected types.
1059 // Do not report participant types, and recursively walk beneath
1060 // them only if participants_hide_witnesses is false.
1061 // If top_level_call is false, skip testing the context type,
1062 // because the caller has already considered it.
1063 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
1064 bool participants_hide_witnesses,
1065 bool top_level_call) {
1066 // Current thread must be in VM (not native mode, as in CI):
1067 assert(must_be_in_vm(), "raw oops here");
1068 // Must not move the class hierarchy during this check:
1069 assert_locked_or_safepoint(Compile_lock);
1071 bool do_counts = count_find_witness_calls();
1073 // Check the root of the sub-hierarchy first.
1074 if (top_level_call) {
1075 if (do_counts) {
1076 NOT_PRODUCT(deps_find_witness_calls++);
1077 NOT_PRODUCT(deps_find_witness_steps++);
1078 }
1079 if (is_participant(context_type)) {
1080 if (participants_hide_witnesses) return NULL;
1081 // else fall through to search loop...
1082 } else if (is_witness(context_type) && !ignore_witness(context_type)) {
1083 // The context is an abstract class or interface, to start with.
1084 return context_type;
1085 }
1086 }
1088 // Now we must check each implementor and each subclass.
1089 // Use a short worklist to avoid blowing the stack.
1090 // Each worklist entry is a *chain* of subklass siblings to process.
1091 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
1092 Klass* chains[CHAINMAX];
1093 int chaini = 0; // index into worklist
1094 Klass* chain; // scratch variable
1095 #define ADD_SUBCLASS_CHAIN(k) { \
1096 assert(chaini < CHAINMAX, "oob"); \
1097 chain = InstanceKlass::cast(k)->subklass(); \
1098 if (chain != NULL) chains[chaini++] = chain; }
1100 // Look for non-abstract subclasses.
1101 // (Note: Interfaces do not have subclasses.)
1102 ADD_SUBCLASS_CHAIN(context_type);
1104 // If it is an interface, search its direct implementors.
1105 // (Their subclasses are additional indirect implementors.
1106 // See InstanceKlass::add_implementor.)
1107 // (Note: nof_implementors is always zero for non-interfaces.)
1108 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
1109 if (nof_impls > 1) {
1110 // Avoid this case: *I.m > { A.m, C }; B.m > C
1111 // Here, I.m has 2 concrete implementations, but m appears unique
1112 // as A.m, because the search misses B.m when checking C.
1113 // The inherited method B.m was getting missed by the walker
1114 // when interface 'I' was the starting point.
1115 // %%% Until this is fixed more systematically, bail out.
1116 // (Old CHA had the same limitation.)
1117 return context_type;
1118 }
1119 if (nof_impls > 0) {
1120 Klass* impl = InstanceKlass::cast(context_type)->implementor();
1121 assert(impl != NULL, "just checking");
1122 // If impl is the same as the context_type, then more than one
1123 // implementor has seen. No exact info in this case.
1124 if (impl == context_type) {
1125 return context_type; // report an inexact witness to this sad affair
1126 }
1127 if (do_counts)
1128 { NOT_PRODUCT(deps_find_witness_steps++); }
1129 if (is_participant(impl)) {
1130 if (!participants_hide_witnesses) {
1131 ADD_SUBCLASS_CHAIN(impl);
1132 }
1133 } else if (is_witness(impl) && !ignore_witness(impl)) {
1134 return impl;
1135 } else {
1136 ADD_SUBCLASS_CHAIN(impl);
1137 }
1138 }
1140 // Recursively process each non-trivial sibling chain.
1141 while (chaini > 0) {
1142 Klass* chain = chains[--chaini];
1143 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
1144 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
1145 if (is_participant(sub)) {
1146 if (participants_hide_witnesses) continue;
1147 // else fall through to process this guy's subclasses
1148 } else if (is_witness(sub) && !ignore_witness(sub)) {
1149 return sub;
1150 }
1151 if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
1152 // Fast path. (Partially disabled if VerifyDependencies.)
1153 ADD_SUBCLASS_CHAIN(sub);
1154 } else {
1155 // Worklist overflow. Do a recursive call. Should be rare.
1156 // The recursive call will have its own worklist, of course.
1157 // (Note that sub has already been tested, so that there is
1158 // no need for the recursive call to re-test. That's handy,
1159 // since the recursive call sees sub as the context_type.)
1160 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
1161 Klass* witness = find_witness_anywhere(sub,
1162 participants_hide_witnesses,
1163 /*top_level_call=*/ false);
1164 if (witness != NULL) return witness;
1165 }
1166 }
1167 }
1169 // No witness found. The dependency remains unbroken.
1170 return NULL;
1171 #undef ADD_SUBCLASS_CHAIN
1172 }
1175 bool Dependencies::is_concrete_klass(Klass* k) {
1176 if (k->is_abstract()) return false;
1177 // %%% We could treat classes which are concrete but
1178 // have not yet been instantiated as virtually abstract.
1179 // This would require a deoptimization barrier on first instantiation.
1180 //if (k->is_not_instantiated()) return false;
1181 return true;
1182 }
1184 bool Dependencies::is_concrete_method(Method* m, Klass * k) {
1185 // NULL is not a concrete method,
1186 // statics are irrelevant to virtual call sites,
1187 // abstract methods are not concrete,
1188 // overpass (error) methods are not concrete if k is abstract
1189 //
1190 // note "true" is conservative answer --
1191 // overpass clause is false if k == NULL, implies return true if
1192 // answer depends on overpass clause.
1193 return ! ( m == NULL || m -> is_static() || m -> is_abstract() ||
1194 m->is_overpass() && k != NULL && k -> is_abstract() );
1195 }
1198 Klass* Dependencies::find_finalizable_subclass(Klass* k) {
1199 if (k->is_interface()) return NULL;
1200 if (k->has_finalizer()) return k;
1201 k = k->subklass();
1202 while (k != NULL) {
1203 Klass* result = find_finalizable_subclass(k);
1204 if (result != NULL) return result;
1205 k = k->next_sibling();
1206 }
1207 return NULL;
1208 }
1211 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
1212 if (k->is_abstract()) return false;
1213 // We could also return false if k does not yet appear to be
1214 // instantiated, if the VM version supports this distinction also.
1215 //if (k->is_not_instantiated()) return false;
1216 return true;
1217 }
1219 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
1220 return k->has_finalizable_subclass();
1221 }
1224 // Any use of the contents (bytecodes) of a method must be
1225 // marked by an "evol_method" dependency, if those contents
1226 // can change. (Note: A method is always dependent on itself.)
1227 Klass* Dependencies::check_evol_method(Method* m) {
1228 assert(must_be_in_vm(), "raw oops here");
1229 // Did somebody do a JVMTI RedefineClasses while our backs were turned?
1230 // Or is there a now a breakpoint?
1231 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
1232 if (m->is_old()
1233 || m->number_of_breakpoints() > 0) {
1234 return m->method_holder();
1235 } else {
1236 return NULL;
1237 }
1238 }
1240 // This is a strong assertion: It is that the given type
1241 // has no subtypes whatever. It is most useful for
1242 // optimizing checks on reflected types or on array types.
1243 // (Checks on types which are derived from real instances
1244 // can be optimized more strongly than this, because we
1245 // know that the checked type comes from a concrete type,
1246 // and therefore we can disregard abstract types.)
1247 Klass* Dependencies::check_leaf_type(Klass* ctxk) {
1248 assert(must_be_in_vm(), "raw oops here");
1249 assert_locked_or_safepoint(Compile_lock);
1250 InstanceKlass* ctx = InstanceKlass::cast(ctxk);
1251 Klass* sub = ctx->subklass();
1252 if (sub != NULL) {
1253 return sub;
1254 } else if (ctx->nof_implementors() != 0) {
1255 // if it is an interface, it must be unimplemented
1256 // (if it is not an interface, nof_implementors is always zero)
1257 Klass* impl = ctx->implementor();
1258 assert(impl != NULL, "must be set");
1259 return impl;
1260 } else {
1261 return NULL;
1262 }
1263 }
1265 // Test the assertion that conck is the only concrete subtype* of ctxk.
1266 // The type conck itself is allowed to have have further concrete subtypes.
1267 // This allows the compiler to narrow occurrences of ctxk by conck,
1268 // when dealing with the types of actual instances.
1269 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
1270 Klass* conck,
1271 KlassDepChange* changes) {
1272 ClassHierarchyWalker wf(conck);
1273 return wf.find_witness_subtype(ctxk, changes);
1274 }
1276 // If a non-concrete class has no concrete subtypes, it is not (yet)
1277 // instantiatable. This can allow the compiler to make some paths go
1278 // dead, if they are gated by a test of the type.
1279 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
1280 KlassDepChange* changes) {
1281 // Find any concrete subtype, with no participants:
1282 ClassHierarchyWalker wf;
1283 return wf.find_witness_subtype(ctxk, changes);
1284 }
1287 // If a concrete class has no concrete subtypes, it can always be
1288 // exactly typed. This allows the use of a cheaper type test.
1289 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
1290 KlassDepChange* changes) {
1291 // Find any concrete subtype, with only the ctxk as participant:
1292 ClassHierarchyWalker wf(ctxk);
1293 return wf.find_witness_subtype(ctxk, changes);
1294 }
1297 // Find the unique concrete proper subtype of ctxk, or NULL if there
1298 // is more than one concrete proper subtype. If there are no concrete
1299 // proper subtypes, return ctxk itself, whether it is concrete or not.
1300 // The returned subtype is allowed to have have further concrete subtypes.
1301 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
1302 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
1303 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
1304 wf.record_witnesses(1); // Record one other witness when walking.
1305 Klass* wit = wf.find_witness_subtype(ctxk);
1306 if (wit != NULL) return NULL; // Too many witnesses.
1307 Klass* conck = wf.participant(0);
1308 if (conck == NULL) {
1309 #ifndef PRODUCT
1310 // Make sure the dependency mechanism will pass this discovery:
1311 if (VerifyDependencies) {
1312 // Turn off dependency tracing while actually testing deps.
1313 FlagSetting fs(TraceDependencies, false);
1314 if (!Dependencies::is_concrete_klass(ctxk)) {
1315 guarantee(NULL ==
1316 (void *)check_abstract_with_no_concrete_subtype(ctxk),
1317 "verify dep.");
1318 } else {
1319 guarantee(NULL ==
1320 (void *)check_concrete_with_no_concrete_subtype(ctxk),
1321 "verify dep.");
1322 }
1323 }
1324 #endif //PRODUCT
1325 return ctxk; // Return ctxk as a flag for "no subtypes".
1326 } else {
1327 #ifndef PRODUCT
1328 // Make sure the dependency mechanism will pass this discovery:
1329 if (VerifyDependencies) {
1330 // Turn off dependency tracing while actually testing deps.
1331 FlagSetting fs(TraceDependencies, false);
1332 if (!Dependencies::is_concrete_klass(ctxk)) {
1333 guarantee(NULL == (void *)
1334 check_abstract_with_unique_concrete_subtype(ctxk, conck),
1335 "verify dep.");
1336 }
1337 }
1338 #endif //PRODUCT
1339 return conck;
1340 }
1341 }
1343 // Test the assertion that the k[12] are the only concrete subtypes of ctxk,
1344 // except possibly for further subtypes of k[12] themselves.
1345 // The context type must be abstract. The types k1 and k2 are themselves
1346 // allowed to have further concrete subtypes.
1347 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
1348 Klass* ctxk,
1349 Klass* k1,
1350 Klass* k2,
1351 KlassDepChange* changes) {
1352 ClassHierarchyWalker wf;
1353 wf.add_participant(k1);
1354 wf.add_participant(k2);
1355 return wf.find_witness_subtype(ctxk, changes);
1356 }
1358 // Search ctxk for concrete implementations. If there are klen or fewer,
1359 // pack them into the given array and return the number.
1360 // Otherwise, return -1, meaning the given array would overflow.
1361 // (Note that a return of 0 means there are exactly no concrete subtypes.)
1362 // In this search, if ctxk is concrete, it will be reported alone.
1363 // For any type CC reported, no proper subtypes of CC will be reported.
1364 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
1365 int klen,
1366 Klass* karray[]) {
1367 ClassHierarchyWalker wf;
1368 wf.record_witnesses(klen);
1369 Klass* wit = wf.find_witness_subtype(ctxk);
1370 if (wit != NULL) return -1; // Too many witnesses.
1371 int num = wf.num_participants();
1372 assert(num <= klen, "oob");
1373 // Pack the result array with the good news.
1374 for (int i = 0; i < num; i++)
1375 karray[i] = wf.participant(i);
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 (Dependencies::is_concrete_klass(ctxk)? -1: num) {
1382 case -1: // ctxk was itself concrete
1383 guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
1384 break;
1385 case 0:
1386 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
1387 "verify dep.");
1388 break;
1389 case 1:
1390 guarantee(NULL == (void *)
1391 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
1392 "verify dep.");
1393 break;
1394 case 2:
1395 guarantee(NULL == (void *)
1396 check_abstract_with_exclusive_concrete_subtypes(ctxk,
1397 karray[0],
1398 karray[1]),
1399 "verify dep.");
1400 break;
1401 default:
1402 ShouldNotReachHere(); // klen > 2 yet supported
1403 }
1404 }
1405 #endif //PRODUCT
1406 return num;
1407 }
1409 // If a class (or interface) has a unique concrete method uniqm, return NULL.
1410 // Otherwise, return a class that contains an interfering method.
1411 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
1412 KlassDepChange* changes) {
1413 // Here is a missing optimization: If uniqm->is_final(),
1414 // we don't really need to search beneath it for overrides.
1415 // This is probably not important, since we don't use dependencies
1416 // to track final methods. (They can't be "definalized".)
1417 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
1418 return wf.find_witness_definer(ctxk, changes);
1419 }
1421 // Find the set of all non-abstract methods under ctxk that match m.
1422 // (The method m must be defined or inherited in ctxk.)
1423 // Include m itself in the set, unless it is abstract.
1424 // If this set has exactly one element, return that element.
1425 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
1426 ClassHierarchyWalker wf(m);
1427 assert(wf.check_method_context(ctxk, m), "proper context");
1428 wf.record_witnesses(1);
1429 Klass* wit = wf.find_witness_definer(ctxk);
1430 if (wit != NULL) return NULL; // Too many witnesses.
1431 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
1432 if (Dependencies::is_concrete_method(m, ctxk)) {
1433 if (fm == NULL) {
1434 // It turns out that m was always the only implementation.
1435 fm = m;
1436 } else if (fm != m) {
1437 // Two conflicting implementations after all.
1438 // (This can happen if m is inherited into ctxk and fm overrides it.)
1439 return NULL;
1440 }
1441 }
1442 #ifndef PRODUCT
1443 // Make sure the dependency mechanism will pass this discovery:
1444 if (VerifyDependencies && fm != NULL) {
1445 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
1446 "verify dep.");
1447 }
1448 #endif //PRODUCT
1449 return fm;
1450 }
1452 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
1453 Method* m1,
1454 Method* m2,
1455 KlassDepChange* changes) {
1456 ClassHierarchyWalker wf(m1);
1457 wf.add_participant(m1->method_holder());
1458 wf.add_participant(m2->method_holder());
1459 return wf.find_witness_definer(ctxk, changes);
1460 }
1462 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
1463 Klass* search_at = ctxk;
1464 if (changes != NULL)
1465 search_at = changes->new_type(); // just look at the new bit
1466 return find_finalizable_subclass(search_at);
1467 }
1469 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
1470 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity");
1471 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity");
1472 if (changes == NULL) {
1473 // Validate all CallSites
1474 if (java_lang_invoke_CallSite::target(call_site) != method_handle)
1475 return call_site->klass(); // assertion failed
1476 } else {
1477 // Validate the given CallSite
1478 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
1479 assert(method_handle != changes->method_handle(), "must be");
1480 return call_site->klass(); // assertion failed
1481 }
1482 }
1483 return NULL; // assertion still valid
1484 }
1487 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) {
1488 if (witness != NULL) {
1489 if (TraceDependencies) {
1490 print_dependency(witness, /*verbose=*/ true);
1491 }
1492 // The following is a no-op unless logging is enabled:
1493 log_dependency(witness);
1494 }
1495 }
1498 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) {
1499 assert_locked_or_safepoint(Compile_lock);
1500 Dependencies::check_valid_dependency_type(type());
1502 Klass* witness = NULL;
1503 switch (type()) {
1504 case evol_method:
1505 witness = check_evol_method(method_argument(0));
1506 break;
1507 case leaf_type:
1508 witness = check_leaf_type(context_type());
1509 break;
1510 case abstract_with_unique_concrete_subtype:
1511 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes);
1512 break;
1513 case abstract_with_no_concrete_subtype:
1514 witness = check_abstract_with_no_concrete_subtype(context_type(), changes);
1515 break;
1516 case concrete_with_no_concrete_subtype:
1517 witness = check_concrete_with_no_concrete_subtype(context_type(), changes);
1518 break;
1519 case unique_concrete_method:
1520 witness = check_unique_concrete_method(context_type(), method_argument(1), changes);
1521 break;
1522 case abstract_with_exclusive_concrete_subtypes_2:
1523 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes);
1524 break;
1525 case exclusive_concrete_methods_2:
1526 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes);
1527 break;
1528 case no_finalizable_subclasses:
1529 witness = check_has_no_finalizable_subclasses(context_type(), changes);
1530 break;
1531 default:
1532 witness = NULL;
1533 break;
1534 }
1535 trace_and_log_witness(witness);
1536 return witness;
1537 }
1540 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) {
1541 assert_locked_or_safepoint(Compile_lock);
1542 Dependencies::check_valid_dependency_type(type());
1544 Klass* witness = NULL;
1545 switch (type()) {
1546 case call_site_target_value:
1547 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
1548 break;
1549 default:
1550 witness = NULL;
1551 break;
1552 }
1553 trace_and_log_witness(witness);
1554 return witness;
1555 }
1558 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
1559 // Handle klass dependency
1560 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type()))
1561 return check_klass_dependency(changes.as_klass_change());
1563 // Handle CallSite dependency
1564 if (changes.is_call_site_change())
1565 return check_call_site_dependency(changes.as_call_site_change());
1567 // irrelevant dependency; skip it
1568 return NULL;
1569 }
1572 void DepChange::print() {
1573 int nsup = 0, nint = 0;
1574 for (ContextStream str(*this); str.next(); ) {
1575 Klass* k = str.klass();
1576 switch (str.change_type()) {
1577 case Change_new_type:
1578 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name());
1579 break;
1580 case Change_new_sub:
1581 if (!WizardMode) {
1582 ++nsup;
1583 } else {
1584 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name());
1585 }
1586 break;
1587 case Change_new_impl:
1588 if (!WizardMode) {
1589 ++nint;
1590 } else {
1591 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name());
1592 }
1593 break;
1594 }
1595 }
1596 if (nsup + nint != 0) {
1597 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
1598 }
1599 }
1601 void DepChange::ContextStream::start() {
1602 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL;
1603 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass);
1604 _klass = new_type;
1605 _ti_base = NULL;
1606 _ti_index = 0;
1607 _ti_limit = 0;
1608 }
1610 bool DepChange::ContextStream::next() {
1611 switch (_change_type) {
1612 case Start_Klass: // initial state; _klass is the new type
1613 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces();
1614 _ti_index = 0;
1615 _change_type = Change_new_type;
1616 return true;
1617 case Change_new_type:
1618 // fall through:
1619 _change_type = Change_new_sub;
1620 case Change_new_sub:
1621 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277
1622 {
1623 _klass = InstanceKlass::cast(_klass)->super();
1624 if (_klass != NULL) {
1625 return true;
1626 }
1627 }
1628 // else set up _ti_limit and fall through:
1629 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
1630 _change_type = Change_new_impl;
1631 case Change_new_impl:
1632 if (_ti_index < _ti_limit) {
1633 _klass = _ti_base->at(_ti_index++);
1634 return true;
1635 }
1636 // fall through:
1637 _change_type = NO_CHANGE; // iterator is exhausted
1638 case NO_CHANGE:
1639 break;
1640 default:
1641 ShouldNotReachHere();
1642 }
1643 return false;
1644 }
1646 void KlassDepChange::initialize() {
1647 // entire transaction must be under this lock:
1648 assert_lock_strong(Compile_lock);
1650 // Mark all dependee and all its superclasses
1651 // Mark transitive interfaces
1652 for (ContextStream str(*this); str.next(); ) {
1653 Klass* d = str.klass();
1654 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking");
1655 InstanceKlass::cast(d)->set_is_marked_dependent(true);
1656 }
1657 }
1659 KlassDepChange::~KlassDepChange() {
1660 // Unmark all dependee and all its superclasses
1661 // Unmark transitive interfaces
1662 for (ContextStream str(*this); str.next(); ) {
1663 Klass* d = str.klass();
1664 InstanceKlass::cast(d)->set_is_marked_dependent(false);
1665 }
1666 }
1668 bool KlassDepChange::involves_context(Klass* k) {
1669 if (k == NULL || !k->oop_is_instance()) {
1670 return false;
1671 }
1672 InstanceKlass* ik = InstanceKlass::cast(k);
1673 bool is_contained = ik->is_marked_dependent();
1674 assert(is_contained == new_type()->is_subtype_of(k),
1675 "correct marking of potential context types");
1676 return is_contained;
1677 }
1679 #ifndef PRODUCT
1680 void Dependencies::print_statistics() {
1681 if (deps_find_witness_print != 0) {
1682 // Call one final time, to flush out the data.
1683 deps_find_witness_print = -1;
1684 count_find_witness_calls();
1685 }
1686 }
1687 #endif