1 /* 2 * Copyright 2005-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_dependencies.cpp.incl" 27 28 29 #ifdef ASSERT 30 static bool must_be_in_vm() { 31 Thread* thread = Thread::current(); 32 if (thread->is_Java_thread()) 33 return ((JavaThread*)thread)->thread_state() == _thread_in_vm; 34 else 35 return true; //something like this: thread->is_VM_thread(); 36 } 37 #endif //ASSERT 38 39 void Dependencies::initialize(ciEnv* env) { 40 Arena* arena = env->arena(); 41 _oop_recorder = env->oop_recorder(); 42 _log = env->log(); 43 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0); 44 DEBUG_ONLY(_deps[end_marker] = NULL); 45 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) { 46 _deps[i] = new(arena) GrowableArray<ciObject*>(arena, 10, 0, 0); 47 } 48 _content_bytes = NULL; 49 _size_in_bytes = (size_t)-1; 50 51 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity"); 52 } 53 54 void Dependencies::assert_evol_method(ciMethod* m) { 55 assert_common_1(evol_method, m); 56 } 57 58 void Dependencies::assert_leaf_type(ciKlass* ctxk) { 59 if (ctxk->is_array_klass()) { 60 // As a special case, support this assertion on an array type, 61 // which reduces to an assertion on its element type. 62 // Note that this cannot be done with assertions that 63 // relate to concreteness or abstractness. 64 ciType* elemt = ctxk->as_array_klass()->base_element_type(); 65 if (!elemt->is_instance_klass()) return; // Ex: int[][] 66 ctxk = elemt->as_instance_klass(); 67 //if (ctxk->is_final()) return; // Ex: String[][] 68 } 69 check_ctxk(ctxk); 70 assert_common_1(leaf_type, ctxk); 71 } 72 73 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) { 74 check_ctxk_abstract(ctxk); 75 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck); 76 } 77 78 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) { 79 check_ctxk_abstract(ctxk); 80 assert_common_1(abstract_with_no_concrete_subtype, ctxk); 81 } 82 83 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) { 84 check_ctxk_concrete(ctxk); 85 assert_common_1(concrete_with_no_concrete_subtype, ctxk); 86 } 87 88 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) { 89 check_ctxk(ctxk); 90 assert_common_2(unique_concrete_method, ctxk, uniqm); 91 } 92 93 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) { 94 check_ctxk(ctxk); 95 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2); 96 } 97 98 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) { 99 check_ctxk(ctxk); 100 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2); 101 } 102 103 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) { 104 check_ctxk(ctxk); 105 assert_common_1(no_finalizable_subclasses, ctxk); 106 } 107 108 // Helper function. If we are adding a new dep. under ctxk2, 109 // try to find an old dep. under a broader* ctxk1. If there is 110 // 111 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciObject*>* deps, 112 int ctxk_i, ciKlass* ctxk2) { 113 ciKlass* ctxk1 = deps->at(ctxk_i)->as_klass(); 114 if (ctxk2->is_subtype_of(ctxk1)) { 115 return true; // success, and no need to change 116 } else if (ctxk1->is_subtype_of(ctxk2)) { 117 // new context class fully subsumes previous one 118 deps->at_put(ctxk_i, ctxk2); 119 return true; 120 } else { 121 return false; 122 } 123 } 124 125 void Dependencies::assert_common_1(Dependencies::DepType dept, ciObject* x) { 126 assert(dep_args(dept) == 1, "sanity"); 127 log_dependency(dept, x); 128 GrowableArray<ciObject*>* deps = _deps[dept]; 129 130 // see if the same (or a similar) dep is already recorded 131 if (note_dep_seen(dept, x)) { 132 assert(deps->find(x) >= 0, "sanity"); 133 } else { 134 deps->append(x); 135 } 136 } 137 138 void Dependencies::assert_common_2(Dependencies::DepType dept, 139 ciKlass* ctxk, ciObject* x) { 140 assert(dep_context_arg(dept) == 0, "sanity"); 141 assert(dep_args(dept) == 2, "sanity"); 142 log_dependency(dept, ctxk, x); 143 GrowableArray<ciObject*>* deps = _deps[dept]; 144 145 // see if the same (or a similar) dep is already recorded 146 if (note_dep_seen(dept, x)) { 147 // look in this bucket for redundant assertions 148 const int stride = 2; 149 for (int i = deps->length(); (i -= stride) >= 0; ) { 150 ciObject* x1 = deps->at(i+1); 151 if (x == x1) { // same subject; check the context 152 if (maybe_merge_ctxk(deps, i+0, ctxk)) { 153 return; 154 } 155 } 156 } 157 } 158 159 // append the assertion in the correct bucket: 160 deps->append(ctxk); 161 deps->append(x); 162 } 163 164 void Dependencies::assert_common_3(Dependencies::DepType dept, 165 ciKlass* ctxk, ciObject* x, ciObject* x2) { 166 assert(dep_context_arg(dept) == 0, "sanity"); 167 assert(dep_args(dept) == 3, "sanity"); 168 log_dependency(dept, ctxk, x, x2); 169 GrowableArray<ciObject*>* deps = _deps[dept]; 170 171 // try to normalize an unordered pair: 172 bool swap = false; 173 switch (dept) { 174 case abstract_with_exclusive_concrete_subtypes_2: 175 swap = (x->ident() > x2->ident() && x != ctxk); 176 break; 177 case exclusive_concrete_methods_2: 178 swap = (x->ident() > x2->ident() && x->as_method()->holder() != ctxk); 179 break; 180 } 181 if (swap) { ciObject* t = x; x = x2; x2 = t; } 182 183 // see if the same (or a similar) dep is already recorded 184 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) { 185 // look in this bucket for redundant assertions 186 const int stride = 3; 187 for (int i = deps->length(); (i -= stride) >= 0; ) { 188 ciObject* y = deps->at(i+1); 189 ciObject* y2 = deps->at(i+2); 190 if (x == y && x2 == y2) { // same subjects; check the context 191 if (maybe_merge_ctxk(deps, i+0, ctxk)) { 192 return; 193 } 194 } 195 } 196 } 197 // append the assertion in the correct bucket: 198 deps->append(ctxk); 199 deps->append(x); 200 deps->append(x2); 201 } 202 203 /// Support for encoding dependencies into an nmethod: 204 205 void Dependencies::copy_to(nmethod* nm) { 206 address beg = nm->dependencies_begin(); 207 address end = nm->dependencies_end(); 208 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing"); 209 Copy::disjoint_words((HeapWord*) content_bytes(), 210 (HeapWord*) beg, 211 size_in_bytes() / sizeof(HeapWord)); 212 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words"); 213 } 214 215 static int sort_dep(ciObject** p1, ciObject** p2, int narg) { 216 for (int i = 0; i < narg; i++) { 217 int diff = p1[i]->ident() - p2[i]->ident(); 218 if (diff != 0) return diff; 219 } 220 return 0; 221 } 222 static int sort_dep_arg_1(ciObject** p1, ciObject** p2) 223 { return sort_dep(p1, p2, 1); } 224 static int sort_dep_arg_2(ciObject** p1, ciObject** p2) 225 { return sort_dep(p1, p2, 2); } 226 static int sort_dep_arg_3(ciObject** p1, ciObject** p2) 227 { return sort_dep(p1, p2, 3); } 228 229 void Dependencies::sort_all_deps() { 230 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 231 DepType dept = (DepType)deptv; 232 GrowableArray<ciObject*>* deps = _deps[dept]; 233 if (deps->length() <= 1) continue; 234 switch (dep_args(dept)) { 235 case 1: deps->sort(sort_dep_arg_1, 1); break; 236 case 2: deps->sort(sort_dep_arg_2, 2); break; 237 case 3: deps->sort(sort_dep_arg_3, 3); break; 238 default: ShouldNotReachHere(); 239 } 240 } 241 } 242 243 size_t Dependencies::estimate_size_in_bytes() { 244 size_t est_size = 100; 245 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 246 DepType dept = (DepType)deptv; 247 GrowableArray<ciObject*>* deps = _deps[dept]; 248 est_size += deps->length()*2; // tags and argument(s) 249 } 250 return est_size; 251 } 252 253 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciObject* x) { 254 switch (dept) { 255 case abstract_with_exclusive_concrete_subtypes_2: 256 return x->as_klass(); 257 case unique_concrete_method: 258 case exclusive_concrete_methods_2: 259 return x->as_method()->holder(); 260 } 261 return NULL; // let NULL be NULL 262 } 263 264 klassOop Dependencies::ctxk_encoded_as_null(DepType dept, oop x) { 265 assert(must_be_in_vm(), "raw oops here"); 266 switch (dept) { 267 case abstract_with_exclusive_concrete_subtypes_2: 268 assert(x->is_klass(), "sanity"); 269 return (klassOop) x; 270 case unique_concrete_method: 271 case exclusive_concrete_methods_2: 272 assert(x->is_method(), "sanity"); 273 return ((methodOop)x)->method_holder(); 274 } 275 return NULL; // let NULL be NULL 276 } 277 278 void Dependencies::encode_content_bytes() { 279 sort_all_deps(); 280 281 // cast is safe, no deps can overflow INT_MAX 282 CompressedWriteStream bytes((int)estimate_size_in_bytes()); 283 284 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 285 DepType dept = (DepType)deptv; 286 GrowableArray<ciObject*>* deps = _deps[dept]; 287 if (deps->length() == 0) continue; 288 int stride = dep_args(dept); 289 int ctxkj = dep_context_arg(dept); // -1 if no context arg 290 assert(stride > 0, "sanity"); 291 for (int i = 0; i < deps->length(); i += stride) { 292 jbyte code_byte = (jbyte)dept; 293 int skipj = -1; 294 if (ctxkj >= 0 && ctxkj+1 < stride) { 295 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_klass(); 296 ciObject* x = deps->at(i+ctxkj+1); // following argument 297 if (ctxk == ctxk_encoded_as_null(dept, x)) { 298 skipj = ctxkj; // we win: maybe one less oop to keep track of 299 code_byte |= default_context_type_bit; 300 } 301 } 302 bytes.write_byte(code_byte); 303 for (int j = 0; j < stride; j++) { 304 if (j == skipj) continue; 305 bytes.write_int(_oop_recorder->find_index(deps->at(i+j)->constant_encoding())); 306 } 307 } 308 } 309 310 // write a sentinel byte to mark the end 311 bytes.write_byte(end_marker); 312 313 // round it out to a word boundary 314 while (bytes.position() % sizeof(HeapWord) != 0) { 315 bytes.write_byte(end_marker); 316 } 317 318 // check whether the dept byte encoding really works 319 assert((jbyte)default_context_type_bit != 0, "byte overflow"); 320 321 _content_bytes = bytes.buffer(); 322 _size_in_bytes = bytes.position(); 323 } 324 325 326 const char* Dependencies::_dep_name[TYPE_LIMIT] = { 327 "end_marker", 328 "evol_method", 329 "leaf_type", 330 "abstract_with_unique_concrete_subtype", 331 "abstract_with_no_concrete_subtype", 332 "concrete_with_no_concrete_subtype", 333 "unique_concrete_method", 334 "abstract_with_exclusive_concrete_subtypes_2", 335 "exclusive_concrete_methods_2", 336 "no_finalizable_subclasses" 337 }; 338 339 int Dependencies::_dep_args[TYPE_LIMIT] = { 340 -1,// end_marker 341 1, // evol_method m 342 1, // leaf_type ctxk 343 2, // abstract_with_unique_concrete_subtype ctxk, k 344 1, // abstract_with_no_concrete_subtype ctxk 345 1, // concrete_with_no_concrete_subtype ctxk 346 2, // unique_concrete_method ctxk, m 347 3, // unique_concrete_subtypes_2 ctxk, k1, k2 348 3, // unique_concrete_methods_2 ctxk, m1, m2 349 1 // no_finalizable_subclasses ctxk 350 }; 351 352 const char* Dependencies::dep_name(Dependencies::DepType dept) { 353 if (!dept_in_mask(dept, all_types)) return "?bad-dep?"; 354 return _dep_name[dept]; 355 } 356 357 int Dependencies::dep_args(Dependencies::DepType dept) { 358 if (!dept_in_mask(dept, all_types)) return -1; 359 return _dep_args[dept]; 360 } 361 362 // for the sake of the compiler log, print out current dependencies: 363 void Dependencies::log_all_dependencies() { 364 if (log() == NULL) return; 365 ciObject* args[max_arg_count]; 366 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 367 DepType dept = (DepType)deptv; 368 GrowableArray<ciObject*>* deps = _deps[dept]; 369 if (deps->length() == 0) continue; 370 int stride = dep_args(dept); 371 for (int i = 0; i < deps->length(); i += stride) { 372 for (int j = 0; j < stride; j++) { 373 // flush out the identities before printing 374 args[j] = deps->at(i+j); 375 } 376 write_dependency_to(log(), dept, stride, args); 377 } 378 } 379 } 380 381 void Dependencies::write_dependency_to(CompileLog* log, 382 DepType dept, 383 int nargs, oop args[], 384 klassOop witness) { 385 if (log == NULL) { 386 return; 387 } 388 ciEnv* env = ciEnv::current(); 389 ciObject* ciargs[max_arg_count]; 390 assert(nargs <= max_arg_count, "oob"); 391 for (int j = 0; j < nargs; j++) { 392 ciargs[j] = env->get_object(args[j]); 393 } 394 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness); 395 } 396 397 void Dependencies::write_dependency_to(CompileLog* log, 398 DepType dept, 399 int nargs, ciObject* args[], 400 klassOop witness) { 401 if (log == NULL) return; 402 assert(nargs <= max_arg_count, "oob"); 403 int argids[max_arg_count]; 404 int ctxkj = dep_context_arg(dept); // -1 if no context arg 405 int j; 406 for (j = 0; j < nargs; j++) { 407 argids[j] = log->identify(args[j]); 408 } 409 if (witness != NULL) { 410 log->begin_elem("dependency_failed"); 411 } else { 412 log->begin_elem("dependency"); 413 } 414 log->print(" type='%s'", dep_name(dept)); 415 if (ctxkj >= 0) { 416 log->print(" ctxk='%d'", argids[ctxkj]); 417 } 418 // write remaining arguments, if any. 419 for (j = 0; j < nargs; j++) { 420 if (j == ctxkj) continue; // already logged 421 if (j == 1) { 422 log->print( " x='%d'", argids[j]); 423 } else { 424 log->print(" x%d='%d'", j, argids[j]); 425 } 426 } 427 if (witness != NULL) { 428 log->object("witness", witness); 429 log->stamp(); 430 } 431 log->end_elem(); 432 } 433 434 void Dependencies::write_dependency_to(xmlStream* xtty, 435 DepType dept, 436 int nargs, oop args[], 437 klassOop witness) { 438 if (xtty == NULL) return; 439 ttyLocker ttyl; 440 int ctxkj = dep_context_arg(dept); // -1 if no context arg 441 if (witness != NULL) { 442 xtty->begin_elem("dependency_failed"); 443 } else { 444 xtty->begin_elem("dependency"); 445 } 446 xtty->print(" type='%s'", dep_name(dept)); 447 if (ctxkj >= 0) { 448 xtty->object("ctxk", args[ctxkj]); 449 } 450 // write remaining arguments, if any. 451 for (int j = 0; j < nargs; j++) { 452 if (j == ctxkj) continue; // already logged 453 if (j == 1) { 454 xtty->object("x", args[j]); 455 } else { 456 char xn[10]; sprintf(xn, "x%d", j); 457 xtty->object(xn, args[j]); 458 } 459 } 460 if (witness != NULL) { 461 xtty->object("witness", witness); 462 xtty->stamp(); 463 } 464 xtty->end_elem(); 465 } 466 467 void Dependencies::print_dependency(DepType dept, int nargs, oop args[], 468 klassOop witness) { 469 ResourceMark rm; 470 ttyLocker ttyl; // keep the following output all in one block 471 tty->print_cr("%s of type %s", 472 (witness == NULL)? "Dependency": "Failed dependency", 473 dep_name(dept)); 474 // print arguments 475 int ctxkj = dep_context_arg(dept); // -1 if no context arg 476 for (int j = 0; j < nargs; j++) { 477 oop arg = args[j]; 478 bool put_star = false; 479 if (arg == NULL) continue; 480 const char* what; 481 if (j == ctxkj) { 482 what = "context"; 483 put_star = !Dependencies::is_concrete_klass((klassOop)arg); 484 } else if (arg->is_method()) { 485 what = "method "; 486 put_star = !Dependencies::is_concrete_method((methodOop)arg); 487 } else if (arg->is_klass()) { 488 what = "class "; 489 } else { 490 what = "object "; 491 } 492 tty->print(" %s = %s", what, (put_star? "*": "")); 493 if (arg->is_klass()) 494 tty->print("%s", Klass::cast((klassOop)arg)->external_name()); 495 else 496 arg->print_value(); 497 tty->cr(); 498 } 499 if (witness != NULL) { 500 bool put_star = !Dependencies::is_concrete_klass(witness); 501 tty->print_cr(" witness = %s%s", 502 (put_star? "*": ""), 503 Klass::cast(witness)->external_name()); 504 } 505 } 506 507 void Dependencies::DepStream::log_dependency(klassOop witness) { 508 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime 509 int nargs = argument_count(); 510 oop args[max_arg_count]; 511 for (int j = 0; j < nargs; j++) { 512 args[j] = argument(j); 513 } 514 if (_deps != NULL && _deps->log() != NULL) { 515 Dependencies::write_dependency_to(_deps->log(), 516 type(), nargs, args, witness); 517 } else { 518 Dependencies::write_dependency_to(xtty, 519 type(), nargs, args, witness); 520 } 521 } 522 523 void Dependencies::DepStream::print_dependency(klassOop witness, bool verbose) { 524 int nargs = argument_count(); 525 oop args[max_arg_count]; 526 for (int j = 0; j < nargs; j++) { 527 args[j] = argument(j); 528 } 529 Dependencies::print_dependency(type(), nargs, args, witness); 530 if (verbose) { 531 if (_code != NULL) { 532 tty->print(" code: "); 533 _code->print_value_on(tty); 534 tty->cr(); 535 } 536 } 537 } 538 539 540 /// Dependency stream support (decodes dependencies from an nmethod): 541 542 #ifdef ASSERT 543 void Dependencies::DepStream::initial_asserts(size_t byte_limit) { 544 assert(must_be_in_vm(), "raw oops here"); 545 _byte_limit = byte_limit; 546 _type = (DepType)(end_marker-1); // defeat "already at end" assert 547 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other"); 548 } 549 #endif //ASSERT 550 551 bool Dependencies::DepStream::next() { 552 assert(_type != end_marker, "already at end"); 553 if (_bytes.position() == 0 && _code != NULL 554 && _code->dependencies_size() == 0) { 555 // Method has no dependencies at all. 556 return false; 557 } 558 int code_byte = (_bytes.read_byte() & 0xFF); 559 if (code_byte == end_marker) { 560 DEBUG_ONLY(_type = end_marker); 561 return false; 562 } else { 563 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit); 564 code_byte -= ctxk_bit; 565 DepType dept = (DepType)code_byte; 566 _type = dept; 567 guarantee((dept - FIRST_TYPE) < (TYPE_LIMIT - FIRST_TYPE), 568 "bad dependency type tag"); 569 int stride = _dep_args[dept]; 570 assert(stride == dep_args(dept), "sanity"); 571 int skipj = -1; 572 if (ctxk_bit != 0) { 573 skipj = 0; // currently the only context argument is at zero 574 assert(skipj == dep_context_arg(dept), "zero arg always ctxk"); 575 } 576 for (int j = 0; j < stride; j++) { 577 _xi[j] = (j == skipj)? 0: _bytes.read_int(); 578 } 579 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns 580 return true; 581 } 582 } 583 584 inline oop Dependencies::DepStream::recorded_oop_at(int i) { 585 return (_code != NULL) 586 ? _code->oop_at(i) 587 : JNIHandles::resolve(_deps->oop_recorder()->handle_at(i)); 588 } 589 590 oop Dependencies::DepStream::argument(int i) { 591 return recorded_oop_at(argument_index(i)); 592 } 593 594 klassOop Dependencies::DepStream::context_type() { 595 assert(must_be_in_vm(), "raw oops here"); 596 int ctxkj = dep_context_arg(_type); // -1 if no context arg 597 if (ctxkj < 0) { 598 return NULL; // for example, evol_method 599 } else { 600 oop k = recorded_oop_at(_xi[ctxkj]); 601 if (k != NULL) { // context type was not compressed away 602 assert(k->is_klass(), "type check"); 603 return (klassOop) k; 604 } else { // recompute "default" context type 605 return ctxk_encoded_as_null(_type, recorded_oop_at(_xi[ctxkj+1])); 606 } 607 } 608 } 609 610 /// Checking dependencies: 611 612 // This hierarchy walker inspects subtypes of a given type, 613 // trying to find a "bad" class which breaks a dependency. 614 // Such a class is called a "witness" to the broken dependency. 615 // While searching around, we ignore "participants", which 616 // are already known to the dependency. 617 class ClassHierarchyWalker { 618 public: 619 enum { PARTICIPANT_LIMIT = 3 }; 620 621 private: 622 // optional method descriptor to check for: 623 symbolOop _name; 624 symbolOop _signature; 625 626 // special classes which are not allowed to be witnesses: 627 klassOop _participants[PARTICIPANT_LIMIT+1]; 628 int _num_participants; 629 630 // cache of method lookups 631 methodOop _found_methods[PARTICIPANT_LIMIT+1]; 632 633 // if non-zero, tells how many witnesses to convert to participants 634 int _record_witnesses; 635 636 void initialize(klassOop participant) { 637 _record_witnesses = 0; 638 _participants[0] = participant; 639 _found_methods[0] = NULL; 640 _num_participants = 0; 641 if (participant != NULL) { 642 // Terminating NULL. 643 _participants[1] = NULL; 644 _found_methods[1] = NULL; 645 _num_participants = 1; 646 } 647 } 648 649 void initialize_from_method(methodOop m) { 650 assert(m != NULL && m->is_method(), "sanity"); 651 _name = m->name(); 652 _signature = m->signature(); 653 } 654 655 public: 656 // The walker is initialized to recognize certain methods and/or types 657 // as friendly participants. 658 ClassHierarchyWalker(klassOop participant, methodOop m) { 659 initialize_from_method(m); 660 initialize(participant); 661 } 662 ClassHierarchyWalker(methodOop m) { 663 initialize_from_method(m); 664 initialize(NULL); 665 } 666 ClassHierarchyWalker(klassOop participant = NULL) { 667 _name = NULL; 668 _signature = NULL; 669 initialize(participant); 670 } 671 672 // This is common code for two searches: One for concrete subtypes, 673 // the other for concrete method implementations and overrides. 674 bool doing_subtype_search() { 675 return _name == NULL; 676 } 677 678 int num_participants() { return _num_participants; } 679 klassOop participant(int n) { 680 assert((uint)n <= (uint)_num_participants, "oob"); 681 return _participants[n]; 682 } 683 684 // Note: If n==num_participants, returns NULL. 685 methodOop found_method(int n) { 686 assert((uint)n <= (uint)_num_participants, "oob"); 687 methodOop fm = _found_methods[n]; 688 assert(n == _num_participants || fm != NULL, "proper usage"); 689 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity"); 690 return fm; 691 } 692 693 #ifdef ASSERT 694 // Assert that m is inherited into ctxk, without intervening overrides. 695 // (May return true even if this is not true, in corner cases where we punt.) 696 bool check_method_context(klassOop ctxk, methodOop m) { 697 if (m->method_holder() == ctxk) 698 return true; // Quick win. 699 if (m->is_private()) 700 return false; // Quick lose. Should not happen. 701 if (!(m->is_public() || m->is_protected())) 702 // The override story is complex when packages get involved. 703 return true; // Must punt the assertion to true. 704 Klass* k = Klass::cast(ctxk); 705 methodOop lm = k->lookup_method(m->name(), m->signature()); 706 if (lm == NULL && k->oop_is_instance()) { 707 // It might be an abstract interface method, devoid of mirandas. 708 lm = ((instanceKlass*)k)->lookup_method_in_all_interfaces(m->name(), 709 m->signature()); 710 } 711 if (lm == m) 712 // Method m is inherited into ctxk. 713 return true; 714 if (lm != NULL) { 715 if (!(lm->is_public() || lm->is_protected())) 716 // Method is [package-]private, so the override story is complex. 717 return true; // Must punt the assertion to true. 718 if ( !Dependencies::is_concrete_method(lm) 719 && !Dependencies::is_concrete_method(m) 720 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder())) 721 // Method m is overridden by lm, but both are non-concrete. 722 return true; 723 } 724 ResourceMark rm; 725 tty->print_cr("Dependency method not found in the associated context:"); 726 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name()); 727 tty->print( " method = "); m->print_short_name(tty); tty->cr(); 728 if (lm != NULL) { 729 tty->print( " found = "); lm->print_short_name(tty); tty->cr(); 730 } 731 return false; 732 } 733 #endif 734 735 void add_participant(klassOop participant) { 736 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob"); 737 int np = _num_participants++; 738 _participants[np] = participant; 739 _participants[np+1] = NULL; 740 _found_methods[np+1] = NULL; 741 } 742 743 void record_witnesses(int add) { 744 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT; 745 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob"); 746 _record_witnesses = add; 747 } 748 749 bool is_witness(klassOop k) { 750 if (doing_subtype_search()) { 751 return Dependencies::is_concrete_klass(k); 752 } else { 753 methodOop m = instanceKlass::cast(k)->find_method(_name, _signature); 754 if (m == NULL || !Dependencies::is_concrete_method(m)) return false; 755 _found_methods[_num_participants] = m; 756 // Note: If add_participant(k) is called, 757 // the method m will already be memoized for it. 758 return true; 759 } 760 } 761 762 bool is_participant(klassOop k) { 763 if (k == _participants[0]) { 764 return true; 765 } else if (_num_participants <= 1) { 766 return false; 767 } else { 768 return in_list(k, &_participants[1]); 769 } 770 } 771 bool ignore_witness(klassOop witness) { 772 if (_record_witnesses == 0) { 773 return false; 774 } else { 775 --_record_witnesses; 776 add_participant(witness); 777 return true; 778 } 779 } 780 static bool in_list(klassOop x, klassOop* list) { 781 for (int i = 0; ; i++) { 782 klassOop y = list[i]; 783 if (y == NULL) break; 784 if (y == x) return true; 785 } 786 return false; // not in list 787 } 788 789 private: 790 // the actual search method: 791 klassOop find_witness_anywhere(klassOop context_type, 792 bool participants_hide_witnesses, 793 bool top_level_call = true); 794 // the spot-checking version: 795 klassOop find_witness_in(DepChange& changes, 796 klassOop context_type, 797 bool participants_hide_witnesses); 798 public: 799 klassOop find_witness_subtype(klassOop context_type, DepChange* changes = NULL) { 800 assert(doing_subtype_search(), "must set up a subtype search"); 801 // When looking for unexpected concrete types, 802 // do not look beneath expected ones. 803 const bool participants_hide_witnesses = true; 804 // CX > CC > C' is OK, even if C' is new. 805 // CX > { CC, C' } is not OK if C' is new, and C' is the witness. 806 if (changes != NULL) { 807 return find_witness_in(*changes, context_type, participants_hide_witnesses); 808 } else { 809 return find_witness_anywhere(context_type, participants_hide_witnesses); 810 } 811 } 812 klassOop find_witness_definer(klassOop context_type, DepChange* changes = NULL) { 813 assert(!doing_subtype_search(), "must set up a method definer search"); 814 // When looking for unexpected concrete methods, 815 // look beneath expected ones, to see if there are overrides. 816 const bool participants_hide_witnesses = true; 817 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness. 818 if (changes != NULL) { 819 return find_witness_in(*changes, context_type, !participants_hide_witnesses); 820 } else { 821 return find_witness_anywhere(context_type, !participants_hide_witnesses); 822 } 823 } 824 }; 825 826 #ifndef PRODUCT 827 static int deps_find_witness_calls = 0; 828 static int deps_find_witness_steps = 0; 829 static int deps_find_witness_recursions = 0; 830 static int deps_find_witness_singles = 0; 831 static int deps_find_witness_print = 0; // set to -1 to force a final print 832 static bool count_find_witness_calls() { 833 if (TraceDependencies || LogCompilation) { 834 int pcount = deps_find_witness_print + 1; 835 bool final_stats = (pcount == 0); 836 bool initial_call = (pcount == 1); 837 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0); 838 if (pcount < 0) pcount = 1; // crude overflow protection 839 deps_find_witness_print = pcount; 840 if (VerifyDependencies && initial_call) { 841 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies"); 842 } 843 if (occasional_print || final_stats) { 844 // Every now and then dump a little info about dependency searching. 845 if (xtty != NULL) { 846 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'", 847 deps_find_witness_calls, 848 deps_find_witness_steps, 849 deps_find_witness_recursions, 850 deps_find_witness_singles); 851 } 852 if (final_stats || (TraceDependencies && WizardMode)) { 853 tty->print_cr("Dependency check (find_witness) " 854 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d", 855 deps_find_witness_calls, 856 deps_find_witness_steps, 857 (double)deps_find_witness_steps / deps_find_witness_calls, 858 deps_find_witness_recursions, 859 deps_find_witness_singles); 860 } 861 } 862 return true; 863 } 864 return false; 865 } 866 #else 867 #define count_find_witness_calls() (0) 868 #endif //PRODUCT 869 870 871 klassOop ClassHierarchyWalker::find_witness_in(DepChange& changes, 872 klassOop context_type, 873 bool participants_hide_witnesses) { 874 assert(changes.involves_context(context_type), "irrelevant dependency"); 875 klassOop new_type = changes.new_type(); 876 877 count_find_witness_calls(); 878 NOT_PRODUCT(deps_find_witness_singles++); 879 880 // Current thread must be in VM (not native mode, as in CI): 881 assert(must_be_in_vm(), "raw oops here"); 882 // Must not move the class hierarchy during this check: 883 assert_locked_or_safepoint(Compile_lock); 884 885 int nof_impls = instanceKlass::cast(context_type)->nof_implementors(); 886 if (nof_impls > 1) { 887 // Avoid this case: *I.m > { A.m, C }; B.m > C 888 // %%% Until this is fixed more systematically, bail out. 889 // See corresponding comment in find_witness_anywhere. 890 return context_type; 891 } 892 893 assert(!is_participant(new_type), "only old classes are participants"); 894 if (participants_hide_witnesses) { 895 // If the new type is a subtype of a participant, we are done. 896 for (int i = 0; i < num_participants(); i++) { 897 klassOop part = participant(i); 898 if (part == NULL) continue; 899 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part), 900 "correct marking of participants, b/c new_type is unique"); 901 if (changes.involves_context(part)) { 902 // new guy is protected from this check by previous participant 903 return NULL; 904 } 905 } 906 } 907 908 if (is_witness(new_type) && 909 !ignore_witness(new_type)) { 910 return new_type; 911 } 912 913 return NULL; 914 } 915 916 917 // Walk hierarchy under a context type, looking for unexpected types. 918 // Do not report participant types, and recursively walk beneath 919 // them only if participants_hide_witnesses is false. 920 // If top_level_call is false, skip testing the context type, 921 // because the caller has already considered it. 922 klassOop ClassHierarchyWalker::find_witness_anywhere(klassOop context_type, 923 bool participants_hide_witnesses, 924 bool top_level_call) { 925 // Current thread must be in VM (not native mode, as in CI): 926 assert(must_be_in_vm(), "raw oops here"); 927 // Must not move the class hierarchy during this check: 928 assert_locked_or_safepoint(Compile_lock); 929 930 bool do_counts = count_find_witness_calls(); 931 932 // Check the root of the sub-hierarchy first. 933 if (top_level_call) { 934 if (do_counts) { 935 NOT_PRODUCT(deps_find_witness_calls++); 936 NOT_PRODUCT(deps_find_witness_steps++); 937 } 938 if (is_participant(context_type)) { 939 if (participants_hide_witnesses) return NULL; 940 // else fall through to search loop... 941 } else if (is_witness(context_type) && !ignore_witness(context_type)) { 942 // The context is an abstract class or interface, to start with. 943 return context_type; 944 } 945 } 946 947 // Now we must check each implementor and each subclass. 948 // Use a short worklist to avoid blowing the stack. 949 // Each worklist entry is a *chain* of subklass siblings to process. 950 const int CHAINMAX = 100; // >= 1 + instanceKlass::implementors_limit 951 Klass* chains[CHAINMAX]; 952 int chaini = 0; // index into worklist 953 Klass* chain; // scratch variable 954 #define ADD_SUBCLASS_CHAIN(k) { \ 955 assert(chaini < CHAINMAX, "oob"); \ 956 chain = instanceKlass::cast(k)->subklass(); \ 957 if (chain != NULL) chains[chaini++] = chain; } 958 959 // Look for non-abstract subclasses. 960 // (Note: Interfaces do not have subclasses.) 961 ADD_SUBCLASS_CHAIN(context_type); 962 963 // If it is an interface, search its direct implementors. 964 // (Their subclasses are additional indirect implementors. 965 // See instanceKlass::add_implementor.) 966 // (Note: nof_implementors is always zero for non-interfaces.) 967 int nof_impls = instanceKlass::cast(context_type)->nof_implementors(); 968 if (nof_impls > 1) { 969 // Avoid this case: *I.m > { A.m, C }; B.m > C 970 // Here, I.m has 2 concrete implementations, but m appears unique 971 // as A.m, because the search misses B.m when checking C. 972 // The inherited method B.m was getting missed by the walker 973 // when interface 'I' was the starting point. 974 // %%% Until this is fixed more systematically, bail out. 975 // (Old CHA had the same limitation.) 976 return context_type; 977 } 978 for (int i = 0; i < nof_impls; i++) { 979 klassOop impl = instanceKlass::cast(context_type)->implementor(i); 980 if (impl == NULL) { 981 // implementors array overflowed => no exact info. 982 return context_type; // report an inexact witness to this sad affair 983 } 984 if (do_counts) 985 { NOT_PRODUCT(deps_find_witness_steps++); } 986 if (is_participant(impl)) { 987 if (participants_hide_witnesses) continue; 988 // else fall through to process this guy's subclasses 989 } else if (is_witness(impl) && !ignore_witness(impl)) { 990 return impl; 991 } 992 ADD_SUBCLASS_CHAIN(impl); 993 } 994 995 // Recursively process each non-trivial sibling chain. 996 while (chaini > 0) { 997 Klass* chain = chains[--chaini]; 998 for (Klass* subk = chain; subk != NULL; subk = subk->next_sibling()) { 999 klassOop sub = subk->as_klassOop(); 1000 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); } 1001 if (is_participant(sub)) { 1002 if (participants_hide_witnesses) continue; 1003 // else fall through to process this guy's subclasses 1004 } else if (is_witness(sub) && !ignore_witness(sub)) { 1005 return sub; 1006 } 1007 if (chaini < (VerifyDependencies? 2: CHAINMAX)) { 1008 // Fast path. (Partially disabled if VerifyDependencies.) 1009 ADD_SUBCLASS_CHAIN(sub); 1010 } else { 1011 // Worklist overflow. Do a recursive call. Should be rare. 1012 // The recursive call will have its own worklist, of course. 1013 // (Note that sub has already been tested, so that there is 1014 // no need for the recursive call to re-test. That's handy, 1015 // since the recursive call sees sub as the context_type.) 1016 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); } 1017 klassOop witness = find_witness_anywhere(sub, 1018 participants_hide_witnesses, 1019 /*top_level_call=*/ false); 1020 if (witness != NULL) return witness; 1021 } 1022 } 1023 } 1024 1025 // No witness found. The dependency remains unbroken. 1026 return NULL; 1027 #undef ADD_SUBCLASS_CHAIN 1028 } 1029 1030 1031 bool Dependencies::is_concrete_klass(klassOop k) { 1032 if (Klass::cast(k)->is_abstract()) return false; 1033 // %%% We could treat classes which are concrete but 1034 // have not yet been instantiated as virtually abstract. 1035 // This would require a deoptimization barrier on first instantiation. 1036 //if (k->is_not_instantiated()) return false; 1037 return true; 1038 } 1039 1040 bool Dependencies::is_concrete_method(methodOop m) { 1041 if (m->is_abstract()) return false; 1042 // %%% We could treat unexecuted methods as virtually abstract also. 1043 // This would require a deoptimization barrier on first execution. 1044 return !m->is_abstract(); 1045 } 1046 1047 1048 Klass* Dependencies::find_finalizable_subclass(Klass* k) { 1049 if (k->is_interface()) return NULL; 1050 if (k->has_finalizer()) return k; 1051 k = k->subklass(); 1052 while (k != NULL) { 1053 Klass* result = find_finalizable_subclass(k); 1054 if (result != NULL) return result; 1055 k = k->next_sibling(); 1056 } 1057 return NULL; 1058 } 1059 1060 1061 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) { 1062 if (k->is_abstract()) return false; 1063 // We could return also false if k does not yet appear to be 1064 // instantiated, if the VM version supports this distinction also. 1065 //if (k->is_not_instantiated()) return false; 1066 return true; 1067 } 1068 1069 bool Dependencies::is_concrete_method(ciMethod* m) { 1070 // Statics are irrelevant to virtual call sites. 1071 if (m->is_static()) return false; 1072 1073 // We could return also false if m does not yet appear to be 1074 // executed, if the VM version supports this distinction also. 1075 return !m->is_abstract(); 1076 } 1077 1078 1079 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) { 1080 return k->has_finalizable_subclass(); 1081 } 1082 1083 1084 // Any use of the contents (bytecodes) of a method must be 1085 // marked by an "evol_method" dependency, if those contents 1086 // can change. (Note: A method is always dependent on itself.) 1087 klassOop Dependencies::check_evol_method(methodOop m) { 1088 assert(must_be_in_vm(), "raw oops here"); 1089 // Did somebody do a JVMTI RedefineClasses while our backs were turned? 1090 // Or is there a now a breakpoint? 1091 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.) 1092 if (m->is_old() 1093 || m->number_of_breakpoints() > 0) { 1094 return m->method_holder(); 1095 } else { 1096 return NULL; 1097 } 1098 } 1099 1100 // This is a strong assertion: It is that the given type 1101 // has no subtypes whatever. It is most useful for 1102 // optimizing checks on reflected types or on array types. 1103 // (Checks on types which are derived from real instances 1104 // can be optimized more strongly than this, because we 1105 // know that the checked type comes from a concrete type, 1106 // and therefore we can disregard abstract types.) 1107 klassOop Dependencies::check_leaf_type(klassOop ctxk) { 1108 assert(must_be_in_vm(), "raw oops here"); 1109 assert_locked_or_safepoint(Compile_lock); 1110 instanceKlass* ctx = instanceKlass::cast(ctxk); 1111 Klass* sub = ctx->subklass(); 1112 if (sub != NULL) { 1113 return sub->as_klassOop(); 1114 } else if (ctx->nof_implementors() != 0) { 1115 // if it is an interface, it must be unimplemented 1116 // (if it is not an interface, nof_implementors is always zero) 1117 klassOop impl = ctx->implementor(0); 1118 return (impl != NULL)? impl: ctxk; 1119 } else { 1120 return NULL; 1121 } 1122 } 1123 1124 // Test the assertion that conck is the only concrete subtype* of ctxk. 1125 // The type conck itself is allowed to have have further concrete subtypes. 1126 // This allows the compiler to narrow occurrences of ctxk by conck, 1127 // when dealing with the types of actual instances. 1128 klassOop Dependencies::check_abstract_with_unique_concrete_subtype(klassOop ctxk, 1129 klassOop conck, 1130 DepChange* changes) { 1131 ClassHierarchyWalker wf(conck); 1132 return wf.find_witness_subtype(ctxk, changes); 1133 } 1134 1135 // If a non-concrete class has no concrete subtypes, it is not (yet) 1136 // instantiatable. This can allow the compiler to make some paths go 1137 // dead, if they are gated by a test of the type. 1138 klassOop Dependencies::check_abstract_with_no_concrete_subtype(klassOop ctxk, 1139 DepChange* changes) { 1140 // Find any concrete subtype, with no participants: 1141 ClassHierarchyWalker wf; 1142 return wf.find_witness_subtype(ctxk, changes); 1143 } 1144 1145 1146 // If a concrete class has no concrete subtypes, it can always be 1147 // exactly typed. This allows the use of a cheaper type test. 1148 klassOop Dependencies::check_concrete_with_no_concrete_subtype(klassOop ctxk, 1149 DepChange* changes) { 1150 // Find any concrete subtype, with only the ctxk as participant: 1151 ClassHierarchyWalker wf(ctxk); 1152 return wf.find_witness_subtype(ctxk, changes); 1153 } 1154 1155 1156 // Find the unique concrete proper subtype of ctxk, or NULL if there 1157 // is more than one concrete proper subtype. If there are no concrete 1158 // proper subtypes, return ctxk itself, whether it is concrete or not. 1159 // The returned subtype is allowed to have have further concrete subtypes. 1160 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }. 1161 klassOop Dependencies::find_unique_concrete_subtype(klassOop ctxk) { 1162 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking. 1163 wf.record_witnesses(1); // Record one other witness when walking. 1164 klassOop wit = wf.find_witness_subtype(ctxk); 1165 if (wit != NULL) return NULL; // Too many witnesses. 1166 klassOop conck = wf.participant(0); 1167 if (conck == NULL) { 1168 #ifndef PRODUCT 1169 // Make sure the dependency mechanism will pass this discovery: 1170 if (VerifyDependencies) { 1171 // Turn off dependency tracing while actually testing deps. 1172 FlagSetting fs(TraceDependencies, false); 1173 if (!Dependencies::is_concrete_klass(ctxk)) { 1174 guarantee(NULL == 1175 (void *)check_abstract_with_no_concrete_subtype(ctxk), 1176 "verify dep."); 1177 } else { 1178 guarantee(NULL == 1179 (void *)check_concrete_with_no_concrete_subtype(ctxk), 1180 "verify dep."); 1181 } 1182 } 1183 #endif //PRODUCT 1184 return ctxk; // Return ctxk as a flag for "no subtypes". 1185 } else { 1186 #ifndef PRODUCT 1187 // Make sure the dependency mechanism will pass this discovery: 1188 if (VerifyDependencies) { 1189 // Turn off dependency tracing while actually testing deps. 1190 FlagSetting fs(TraceDependencies, false); 1191 if (!Dependencies::is_concrete_klass(ctxk)) { 1192 guarantee(NULL == (void *) 1193 check_abstract_with_unique_concrete_subtype(ctxk, conck), 1194 "verify dep."); 1195 } 1196 } 1197 #endif //PRODUCT 1198 return conck; 1199 } 1200 } 1201 1202 // Test the assertion that the k[12] are the only concrete subtypes of ctxk, 1203 // except possibly for further subtypes of k[12] themselves. 1204 // The context type must be abstract. The types k1 and k2 are themselves 1205 // allowed to have further concrete subtypes. 1206 klassOop Dependencies::check_abstract_with_exclusive_concrete_subtypes( 1207 klassOop ctxk, 1208 klassOop k1, 1209 klassOop k2, 1210 DepChange* changes) { 1211 ClassHierarchyWalker wf; 1212 wf.add_participant(k1); 1213 wf.add_participant(k2); 1214 return wf.find_witness_subtype(ctxk, changes); 1215 } 1216 1217 // Search ctxk for concrete implementations. If there are klen or fewer, 1218 // pack them into the given array and return the number. 1219 // Otherwise, return -1, meaning the given array would overflow. 1220 // (Note that a return of 0 means there are exactly no concrete subtypes.) 1221 // In this search, if ctxk is concrete, it will be reported alone. 1222 // For any type CC reported, no proper subtypes of CC will be reported. 1223 int Dependencies::find_exclusive_concrete_subtypes(klassOop ctxk, 1224 int klen, 1225 klassOop karray[]) { 1226 ClassHierarchyWalker wf; 1227 wf.record_witnesses(klen); 1228 klassOop wit = wf.find_witness_subtype(ctxk); 1229 if (wit != NULL) return -1; // Too many witnesses. 1230 int num = wf.num_participants(); 1231 assert(num <= klen, "oob"); 1232 // Pack the result array with the good news. 1233 for (int i = 0; i < num; i++) 1234 karray[i] = wf.participant(i); 1235 #ifndef PRODUCT 1236 // Make sure the dependency mechanism will pass this discovery: 1237 if (VerifyDependencies) { 1238 // Turn off dependency tracing while actually testing deps. 1239 FlagSetting fs(TraceDependencies, false); 1240 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) { 1241 case -1: // ctxk was itself concrete 1242 guarantee(num == 1 && karray[0] == ctxk, "verify dep."); 1243 break; 1244 case 0: 1245 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk), 1246 "verify dep."); 1247 break; 1248 case 1: 1249 guarantee(NULL == (void *) 1250 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]), 1251 "verify dep."); 1252 break; 1253 case 2: 1254 guarantee(NULL == (void *) 1255 check_abstract_with_exclusive_concrete_subtypes(ctxk, 1256 karray[0], 1257 karray[1]), 1258 "verify dep."); 1259 break; 1260 default: 1261 ShouldNotReachHere(); // klen > 2 yet supported 1262 } 1263 } 1264 #endif //PRODUCT 1265 return num; 1266 } 1267 1268 // If a class (or interface) has a unique concrete method uniqm, return NULL. 1269 // Otherwise, return a class that contains an interfering method. 1270 klassOop Dependencies::check_unique_concrete_method(klassOop ctxk, methodOop uniqm, 1271 DepChange* changes) { 1272 // Here is a missing optimization: If uniqm->is_final(), 1273 // we don't really need to search beneath it for overrides. 1274 // This is probably not important, since we don't use dependencies 1275 // to track final methods. (They can't be "definalized".) 1276 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm); 1277 return wf.find_witness_definer(ctxk, changes); 1278 } 1279 1280 // Find the set of all non-abstract methods under ctxk that match m. 1281 // (The method m must be defined or inherited in ctxk.) 1282 // Include m itself in the set, unless it is abstract. 1283 // If this set has exactly one element, return that element. 1284 methodOop Dependencies::find_unique_concrete_method(klassOop ctxk, methodOop m) { 1285 ClassHierarchyWalker wf(m); 1286 assert(wf.check_method_context(ctxk, m), "proper context"); 1287 wf.record_witnesses(1); 1288 klassOop wit = wf.find_witness_definer(ctxk); 1289 if (wit != NULL) return NULL; // Too many witnesses. 1290 methodOop fm = wf.found_method(0); // Will be NULL if num_parts == 0. 1291 if (Dependencies::is_concrete_method(m)) { 1292 if (fm == NULL) { 1293 // It turns out that m was always the only implementation. 1294 fm = m; 1295 } else if (fm != m) { 1296 // Two conflicting implementations after all. 1297 // (This can happen if m is inherited into ctxk and fm overrides it.) 1298 return NULL; 1299 } 1300 } 1301 #ifndef PRODUCT 1302 // Make sure the dependency mechanism will pass this discovery: 1303 if (VerifyDependencies && fm != NULL) { 1304 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm), 1305 "verify dep."); 1306 } 1307 #endif //PRODUCT 1308 return fm; 1309 } 1310 1311 klassOop Dependencies::check_exclusive_concrete_methods(klassOop ctxk, 1312 methodOop m1, 1313 methodOop m2, 1314 DepChange* changes) { 1315 ClassHierarchyWalker wf(m1); 1316 wf.add_participant(m1->method_holder()); 1317 wf.add_participant(m2->method_holder()); 1318 return wf.find_witness_definer(ctxk, changes); 1319 } 1320 1321 // Find the set of all non-abstract methods under ctxk that match m[0]. 1322 // (The method m[0] must be defined or inherited in ctxk.) 1323 // Include m itself in the set, unless it is abstract. 1324 // Fill the given array m[0..(mlen-1)] with this set, and return the length. 1325 // (The length may be zero if no concrete methods are found anywhere.) 1326 // If there are too many concrete methods to fit in marray, return -1. 1327 int Dependencies::find_exclusive_concrete_methods(klassOop ctxk, 1328 int mlen, 1329 methodOop marray[]) { 1330 methodOop m0 = marray[0]; 1331 ClassHierarchyWalker wf(m0); 1332 assert(wf.check_method_context(ctxk, m0), "proper context"); 1333 wf.record_witnesses(mlen); 1334 bool participants_hide_witnesses = true; 1335 klassOop wit = wf.find_witness_definer(ctxk); 1336 if (wit != NULL) return -1; // Too many witnesses. 1337 int num = wf.num_participants(); 1338 assert(num <= mlen, "oob"); 1339 // Keep track of whether m is also part of the result set. 1340 int mfill = 0; 1341 assert(marray[mfill] == m0, "sanity"); 1342 if (Dependencies::is_concrete_method(m0)) 1343 mfill++; // keep m0 as marray[0], the first result 1344 for (int i = 0; i < num; i++) { 1345 methodOop fm = wf.found_method(i); 1346 if (fm == m0) continue; // Already put this guy in the list. 1347 if (mfill == mlen) { 1348 return -1; // Oops. Too many methods after all! 1349 } 1350 marray[mfill++] = fm; 1351 } 1352 #ifndef PRODUCT 1353 // Make sure the dependency mechanism will pass this discovery: 1354 if (VerifyDependencies) { 1355 // Turn off dependency tracing while actually testing deps. 1356 FlagSetting fs(TraceDependencies, false); 1357 switch (mfill) { 1358 case 1: 1359 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]), 1360 "verify dep."); 1361 break; 1362 case 2: 1363 guarantee(NULL == (void *) 1364 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]), 1365 "verify dep."); 1366 break; 1367 default: 1368 ShouldNotReachHere(); // mlen > 2 yet supported 1369 } 1370 } 1371 #endif //PRODUCT 1372 return mfill; 1373 } 1374 1375 1376 klassOop Dependencies::check_has_no_finalizable_subclasses(klassOop ctxk, DepChange* changes) { 1377 Klass* search_at = ctxk->klass_part(); 1378 if (changes != NULL) 1379 search_at = changes->new_type()->klass_part(); // just look at the new bit 1380 Klass* result = find_finalizable_subclass(search_at); 1381 if (result == NULL) { 1382 return NULL; 1383 } 1384 return result->as_klassOop(); 1385 } 1386 1387 1388 klassOop Dependencies::DepStream::check_dependency_impl(DepChange* changes) { 1389 assert_locked_or_safepoint(Compile_lock); 1390 1391 klassOop witness = NULL; 1392 switch (type()) { 1393 case evol_method: 1394 witness = check_evol_method(method_argument(0)); 1395 break; 1396 case leaf_type: 1397 witness = check_leaf_type(context_type()); 1398 break; 1399 case abstract_with_unique_concrete_subtype: 1400 witness = check_abstract_with_unique_concrete_subtype(context_type(), 1401 type_argument(1), 1402 changes); 1403 break; 1404 case abstract_with_no_concrete_subtype: 1405 witness = check_abstract_with_no_concrete_subtype(context_type(), 1406 changes); 1407 break; 1408 case concrete_with_no_concrete_subtype: 1409 witness = check_concrete_with_no_concrete_subtype(context_type(), 1410 changes); 1411 break; 1412 case unique_concrete_method: 1413 witness = check_unique_concrete_method(context_type(), 1414 method_argument(1), 1415 changes); 1416 break; 1417 case abstract_with_exclusive_concrete_subtypes_2: 1418 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), 1419 type_argument(1), 1420 type_argument(2), 1421 changes); 1422 break; 1423 case exclusive_concrete_methods_2: 1424 witness = check_exclusive_concrete_methods(context_type(), 1425 method_argument(1), 1426 method_argument(2), 1427 changes); 1428 break; 1429 case no_finalizable_subclasses: 1430 witness = check_has_no_finalizable_subclasses(context_type(), 1431 changes); 1432 break; 1433 default: 1434 witness = NULL; 1435 ShouldNotReachHere(); 1436 break; 1437 } 1438 if (witness != NULL) { 1439 if (TraceDependencies) { 1440 print_dependency(witness, /*verbose=*/ true); 1441 } 1442 // The following is a no-op unless logging is enabled: 1443 log_dependency(witness); 1444 } 1445 return witness; 1446 } 1447 1448 1449 klassOop Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) { 1450 if (!changes.involves_context(context_type())) 1451 // irrelevant dependency; skip it 1452 return NULL; 1453 1454 return check_dependency_impl(&changes); 1455 } 1456 1457 1458 void DepChange::initialize() { 1459 // entire transaction must be under this lock: 1460 assert_lock_strong(Compile_lock); 1461 1462 // Mark all dependee and all its superclasses 1463 // Mark transitive interfaces 1464 for (ContextStream str(*this); str.next(); ) { 1465 klassOop d = str.klass(); 1466 assert(!instanceKlass::cast(d)->is_marked_dependent(), "checking"); 1467 instanceKlass::cast(d)->set_is_marked_dependent(true); 1468 } 1469 } 1470 1471 DepChange::~DepChange() { 1472 // Unmark all dependee and all its superclasses 1473 // Unmark transitive interfaces 1474 for (ContextStream str(*this); str.next(); ) { 1475 klassOop d = str.klass(); 1476 instanceKlass::cast(d)->set_is_marked_dependent(false); 1477 } 1478 } 1479 1480 bool DepChange::involves_context(klassOop k) { 1481 if (k == NULL || !Klass::cast(k)->oop_is_instance()) { 1482 return false; 1483 } 1484 instanceKlass* ik = instanceKlass::cast(k); 1485 bool is_contained = ik->is_marked_dependent(); 1486 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k), 1487 "correct marking of potential context types"); 1488 return is_contained; 1489 } 1490 1491 bool DepChange::ContextStream::next() { 1492 switch (_change_type) { 1493 case Start_Klass: // initial state; _klass is the new type 1494 _ti_base = instanceKlass::cast(_klass)->transitive_interfaces(); 1495 _ti_index = 0; 1496 _change_type = Change_new_type; 1497 return true; 1498 case Change_new_type: 1499 // fall through: 1500 _change_type = Change_new_sub; 1501 case Change_new_sub: 1502 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277 1503 { 1504 _klass = instanceKlass::cast(_klass)->super(); 1505 if (_klass != NULL) { 1506 return true; 1507 } 1508 } 1509 // else set up _ti_limit and fall through: 1510 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length(); 1511 _change_type = Change_new_impl; 1512 case Change_new_impl: 1513 if (_ti_index < _ti_limit) { 1514 _klass = klassOop( _ti_base->obj_at(_ti_index++) ); 1515 return true; 1516 } 1517 // fall through: 1518 _change_type = NO_CHANGE; // iterator is exhausted 1519 case NO_CHANGE: 1520 break; 1521 default: 1522 ShouldNotReachHere(); 1523 } 1524 return false; 1525 } 1526 1527 void DepChange::print() { 1528 int nsup = 0, nint = 0; 1529 for (ContextStream str(*this); str.next(); ) { 1530 klassOop k = str.klass(); 1531 switch (str.change_type()) { 1532 case Change_new_type: 1533 tty->print_cr(" dependee = %s", instanceKlass::cast(k)->external_name()); 1534 break; 1535 case Change_new_sub: 1536 if (!WizardMode) { 1537 ++nsup; 1538 } else { 1539 tty->print_cr(" context super = %s", instanceKlass::cast(k)->external_name()); 1540 } 1541 break; 1542 case Change_new_impl: 1543 if (!WizardMode) { 1544 ++nint; 1545 } else { 1546 tty->print_cr(" context interface = %s", instanceKlass::cast(k)->external_name()); 1547 } 1548 break; 1549 } 1550 } 1551 if (nsup + nint != 0) { 1552 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint); 1553 } 1554 } 1555 1556 #ifndef PRODUCT 1557 void Dependencies::print_statistics() { 1558 if (deps_find_witness_print != 0) { 1559 // Call one final time, to flush out the data. 1560 deps_find_witness_print = -1; 1561 count_find_witness_calls(); 1562 } 1563 } 1564 #endif