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 */ 24 25 #include "precompiled.hpp" 26 #include "ci/ciArrayKlass.hpp" 27 #include "ci/ciEnv.hpp" 28 #include "ci/ciKlass.hpp" 29 #include "ci/ciMethod.hpp" 30 #include "code/dependencies.hpp" 31 #include "compiler/compileLog.hpp" 32 #include "oops/oop.inline.hpp" 33 #include "runtime/handles.hpp" 34 #include "runtime/handles.inline.hpp" 35 #include "runtime/thread.inline.hpp" 36 #include "utilities/copy.hpp" 37 38 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 48 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; 60 61 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity"); 62 } 63 64 void Dependencies::assert_evol_method(ciMethod* m) { 65 assert_common_1(evol_method, m); 66 } 67 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 } 82 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 } 87 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 } 92 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 } 97 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 } 102 103 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 } 107 108 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 } 112 113 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) { 114 check_ctxk(ctxk); 115 assert_common_1(no_finalizable_subclasses, ctxk); 116 } 117 118 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 } 122 123 // 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 } 139 140 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]; 144 145 // 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 } 152 153 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]; 158 159 // 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 } 189 190 // append the assertion in the correct bucket: 191 deps->append(x0); 192 deps->append(x1); 193 } 194 195 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]; 201 202 // 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; } 213 214 // 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 } 233 234 /// Support for encoding dependencies into an nmethod: 235 236 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 } 245 246 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); } 259 260 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 } 273 274 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 } 283 284 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 } 294 295 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 } 308 309 void Dependencies::encode_content_bytes() { 310 sort_all_deps(); 311 312 // cast is safe, no deps can overflow INT_MAX 313 CompressedWriteStream bytes((int)estimate_size_in_bytes()); 314 315 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 } 348 349 // write a sentinel byte to mark the end 350 bytes.write_byte(end_marker); 351 352 // round it out to a word boundary 353 while (bytes.position() % sizeof(HeapWord) != 0) { 354 bytes.write_byte(end_marker); 355 } 356 357 // check whether the dept byte encoding really works 358 assert((jbyte)default_context_type_bit != 0, "byte overflow"); 359 360 _content_bytes = bytes.buffer(); 361 _size_in_bytes = bytes.position(); 362 } 363 364 365 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 }; 378 379 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 }; 392 393 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 } 397 398 int Dependencies::dep_args(Dependencies::DepType dept) { 399 if (!dept_in_mask(dept, all_types)) return -1; 400 return _dep_args[dept]; 401 } 402 403 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 } 406 407 // 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 } 431 432 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 } 454 455 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 } 497 498 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 } 542 543 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 if (arg.is_oop()) { 575 arg.oop_value()->print_value_on(tty); 576 } else { 577 ShouldNotReachHere(); // Provide impl for this type. 578 } 579 580 tty->cr(); 581 } 582 if (witness != NULL) { 583 bool put_star = !Dependencies::is_concrete_klass(witness); 584 tty->print_cr(" witness = %s%s", 585 (put_star? "*": ""), 586 witness->external_name()); 587 } 588 } 589 590 void Dependencies::DepStream::log_dependency(Klass* witness) { 591 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime 592 ResourceMark rm; 593 const int nargs = argument_count(); 594 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs); 595 for (int j = 0; j < nargs; j++) { 596 if (type() == call_site_target_value) { 597 args->push(argument_oop(j)); 598 } else { 599 args->push(argument(j)); 600 } 601 } 602 int argslen = args->length(); 603 if (_deps != NULL && _deps->log() != NULL) { 604 Dependencies::write_dependency_to(_deps->log(), type(), args, witness); 605 } else { 606 Dependencies::write_dependency_to(xtty, type(), args, witness); 607 } 608 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope"); 609 } 610 611 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) { 612 ResourceMark rm; 613 int nargs = argument_count(); 614 GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs); 615 for (int j = 0; j < nargs; j++) { 616 if (type() == call_site_target_value) { 617 args->push(argument_oop(j)); 618 } else { 619 args->push(argument(j)); 620 } 621 } 622 int argslen = args->length(); 623 Dependencies::print_dependency(type(), args, witness); 624 if (verbose) { 625 if (_code != NULL) { 626 tty->print(" code: "); 627 _code->print_value_on(tty); 628 tty->cr(); 629 } 630 } 631 guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope"); 632 } 633 634 635 /// Dependency stream support (decodes dependencies from an nmethod): 636 637 #ifdef ASSERT 638 void Dependencies::DepStream::initial_asserts(size_t byte_limit) { 639 assert(must_be_in_vm(), "raw oops here"); 640 _byte_limit = byte_limit; 641 _type = (DepType)(end_marker-1); // defeat "already at end" assert 642 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other"); 643 } 644 #endif //ASSERT 645 646 bool Dependencies::DepStream::next() { 647 assert(_type != end_marker, "already at end"); 648 if (_bytes.position() == 0 && _code != NULL 649 && _code->dependencies_size() == 0) { 650 // Method has no dependencies at all. 651 return false; 652 } 653 int code_byte = (_bytes.read_byte() & 0xFF); 654 if (code_byte == end_marker) { 655 DEBUG_ONLY(_type = end_marker); 656 return false; 657 } else { 658 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit); 659 code_byte -= ctxk_bit; 660 DepType dept = (DepType)code_byte; 661 _type = dept; 662 Dependencies::check_valid_dependency_type(dept); 663 int stride = _dep_args[dept]; 664 assert(stride == dep_args(dept), "sanity"); 665 int skipj = -1; 666 if (ctxk_bit != 0) { 667 skipj = 0; // currently the only context argument is at zero 668 assert(skipj == dep_context_arg(dept), "zero arg always ctxk"); 669 } 670 for (int j = 0; j < stride; j++) { 671 _xi[j] = (j == skipj)? 0: _bytes.read_int(); 672 } 673 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns 674 return true; 675 } 676 } 677 678 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) { 679 Metadata* o = NULL; 680 if (_code != NULL) { 681 o = _code->metadata_at(i); 682 } else { 683 o = _deps->oop_recorder()->metadata_at(i); 684 } 685 return o; 686 } 687 688 inline oop Dependencies::DepStream::recorded_oop_at(int i) { 689 return (_code != NULL) 690 ? _code->oop_at(i) 691 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i)); 692 } 693 694 Metadata* Dependencies::DepStream::argument(int i) { 695 Metadata* result = recorded_metadata_at(argument_index(i)); 696 697 if (result == NULL) { // Explicit context argument can be compressed 698 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 699 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) { 700 result = ctxk_encoded_as_null(type(), argument(ctxkj+1)); 701 } 702 } 703 704 assert(result == NULL || result->is_klass() || result->is_method(), "must be"); 705 return result; 706 } 707 708 /** 709 * Returns a unique identifier for each dependency argument. 710 */ 711 uintptr_t Dependencies::DepStream::get_identifier(int i) { 712 if (has_oop_argument()) { 713 return (uintptr_t)(oopDesc*)argument_oop(i); 714 } else { 715 return (uintptr_t)argument(i); 716 } 717 } 718 719 oop Dependencies::DepStream::argument_oop(int i) { 720 oop result = recorded_oop_at(argument_index(i)); 721 assert(result == NULL || result->is_oop(), "must be"); 722 return result; 723 } 724 725 Klass* Dependencies::DepStream::context_type() { 726 assert(must_be_in_vm(), "raw oops here"); 727 728 // Most dependencies have an explicit context type argument. 729 { 730 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 731 if (ctxkj >= 0) { 732 Metadata* k = argument(ctxkj); 733 assert(k != NULL && k->is_klass(), "type check"); 734 return (Klass*)k; 735 } 736 } 737 738 // Some dependencies are using the klass of the first object 739 // argument as implicit context type (e.g. call_site_target_value). 740 { 741 int ctxkj = dep_implicit_context_arg(type()); 742 if (ctxkj >= 0) { 743 Klass* k = argument_oop(ctxkj)->klass(); 744 assert(k != NULL && k->is_klass(), "type check"); 745 return (Klass*) k; 746 } 747 } 748 749 // And some dependencies don't have a context type at all, 750 // e.g. evol_method. 751 return NULL; 752 } 753 754 // ----------------- DependencySignature -------------------------------------- 755 bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) { 756 if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) { 757 return false; 758 } 759 760 for (int i = 0; i < s1.args_count(); i++) { 761 if (s1.arg(i) != s2.arg(i)) { 762 return false; 763 } 764 } 765 return true; 766 } 767 768 /// Checking dependencies: 769 770 // This hierarchy walker inspects subtypes of a given type, 771 // trying to find a "bad" class which breaks a dependency. 772 // Such a class is called a "witness" to the broken dependency. 773 // While searching around, we ignore "participants", which 774 // are already known to the dependency. 775 class ClassHierarchyWalker { 776 public: 777 enum { PARTICIPANT_LIMIT = 3 }; 778 779 private: 780 // optional method descriptor to check for: 781 Symbol* _name; 782 Symbol* _signature; 783 784 // special classes which are not allowed to be witnesses: 785 Klass* _participants[PARTICIPANT_LIMIT+1]; 786 int _num_participants; 787 788 // cache of method lookups 789 Method* _found_methods[PARTICIPANT_LIMIT+1]; 790 791 // if non-zero, tells how many witnesses to convert to participants 792 int _record_witnesses; 793 794 void initialize(Klass* participant) { 795 _record_witnesses = 0; 796 _participants[0] = participant; 797 _found_methods[0] = NULL; 798 _num_participants = 0; 799 if (participant != NULL) { 800 // Terminating NULL. 801 _participants[1] = NULL; 802 _found_methods[1] = NULL; 803 _num_participants = 1; 804 } 805 } 806 807 void initialize_from_method(Method* m) { 808 assert(m != NULL && m->is_method(), "sanity"); 809 _name = m->name(); 810 _signature = m->signature(); 811 } 812 813 public: 814 // The walker is initialized to recognize certain methods and/or types 815 // as friendly participants. 816 ClassHierarchyWalker(Klass* participant, Method* m) { 817 initialize_from_method(m); 818 initialize(participant); 819 } 820 ClassHierarchyWalker(Method* m) { 821 initialize_from_method(m); 822 initialize(NULL); 823 } 824 ClassHierarchyWalker(Klass* participant = NULL) { 825 _name = NULL; 826 _signature = NULL; 827 initialize(participant); 828 } 829 830 // This is common code for two searches: One for concrete subtypes, 831 // the other for concrete method implementations and overrides. 832 bool doing_subtype_search() { 833 return _name == NULL; 834 } 835 836 int num_participants() { return _num_participants; } 837 Klass* participant(int n) { 838 assert((uint)n <= (uint)_num_participants, "oob"); 839 return _participants[n]; 840 } 841 842 // Note: If n==num_participants, returns NULL. 843 Method* found_method(int n) { 844 assert((uint)n <= (uint)_num_participants, "oob"); 845 Method* fm = _found_methods[n]; 846 assert(n == _num_participants || fm != NULL, "proper usage"); 847 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity"); 848 return fm; 849 } 850 851 #ifdef ASSERT 852 // Assert that m is inherited into ctxk, without intervening overrides. 853 // (May return true even if this is not true, in corner cases where we punt.) 854 bool check_method_context(Klass* ctxk, Method* m) { 855 if (m->method_holder() == ctxk) 856 return true; // Quick win. 857 if (m->is_private()) 858 return false; // Quick lose. Should not happen. 859 if (!(m->is_public() || m->is_protected())) 860 // The override story is complex when packages get involved. 861 return true; // Must punt the assertion to true. 862 Klass* k = ctxk; 863 Method* lm = k->lookup_method(m->name(), m->signature()); 864 if (lm == NULL && k->oop_is_instance()) { 865 // It might be an interface method 866 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(), 867 m->signature()); 868 } 869 if (lm == m) 870 // Method m is inherited into ctxk. 871 return true; 872 if (lm != NULL) { 873 if (!(lm->is_public() || lm->is_protected())) { 874 // Method is [package-]private, so the override story is complex. 875 return true; // Must punt the assertion to true. 876 } 877 if (lm->is_static()) { 878 // Static methods don't override non-static so punt 879 return true; 880 } 881 if ( !Dependencies::is_concrete_method(lm, k) 882 && !Dependencies::is_concrete_method(m, ctxk) 883 && lm->method_holder()->is_subtype_of(m->method_holder())) 884 // Method m is overridden by lm, but both are non-concrete. 885 return true; 886 } 887 ResourceMark rm; 888 tty->print_cr("Dependency method not found in the associated context:"); 889 tty->print_cr(" context = %s", ctxk->external_name()); 890 tty->print( " method = "); m->print_short_name(tty); tty->cr(); 891 if (lm != NULL) { 892 tty->print( " found = "); lm->print_short_name(tty); tty->cr(); 893 } 894 return false; 895 } 896 #endif 897 898 void add_participant(Klass* participant) { 899 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob"); 900 int np = _num_participants++; 901 _participants[np] = participant; 902 _participants[np+1] = NULL; 903 _found_methods[np+1] = NULL; 904 } 905 906 void record_witnesses(int add) { 907 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT; 908 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob"); 909 _record_witnesses = add; 910 } 911 912 bool is_witness(Klass* k) { 913 if (doing_subtype_search()) { 914 return Dependencies::is_concrete_klass(k); 915 } else if (!k->oop_is_instance()) { 916 return false; // no methods to find in an array type 917 } else { 918 // Search class hierarchy first. 919 Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature); 920 if (!Dependencies::is_concrete_method(m, k)) { 921 // Check interface defaults also, if any exist. 922 Array<Method*>* default_methods = InstanceKlass::cast(k)->default_methods(); 923 if (default_methods == NULL) 924 return false; 925 m = InstanceKlass::cast(k)->find_method(default_methods, _name, _signature); 926 if (!Dependencies::is_concrete_method(m, NULL)) 927 return false; 928 } 929 _found_methods[_num_participants] = m; 930 // Note: If add_participant(k) is called, 931 // the method m will already be memoized for it. 932 return true; 933 } 934 } 935 936 bool is_participant(Klass* k) { 937 if (k == _participants[0]) { 938 return true; 939 } else if (_num_participants <= 1) { 940 return false; 941 } else { 942 return in_list(k, &_participants[1]); 943 } 944 } 945 bool ignore_witness(Klass* witness) { 946 if (_record_witnesses == 0) { 947 return false; 948 } else { 949 --_record_witnesses; 950 add_participant(witness); 951 return true; 952 } 953 } 954 static bool in_list(Klass* x, Klass** list) { 955 for (int i = 0; ; i++) { 956 Klass* y = list[i]; 957 if (y == NULL) break; 958 if (y == x) return true; 959 } 960 return false; // not in list 961 } 962 963 private: 964 // the actual search method: 965 Klass* find_witness_anywhere(Klass* context_type, 966 bool participants_hide_witnesses, 967 bool top_level_call = true); 968 // the spot-checking version: 969 Klass* find_witness_in(KlassDepChange& changes, 970 Klass* context_type, 971 bool participants_hide_witnesses); 972 public: 973 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) { 974 assert(doing_subtype_search(), "must set up a subtype search"); 975 // When looking for unexpected concrete types, 976 // do not look beneath expected ones. 977 const bool participants_hide_witnesses = true; 978 // CX > CC > C' is OK, even if C' is new. 979 // CX > { CC, C' } is not OK if C' is new, and C' is the witness. 980 if (changes != NULL) { 981 return find_witness_in(*changes, context_type, participants_hide_witnesses); 982 } else { 983 return find_witness_anywhere(context_type, participants_hide_witnesses); 984 } 985 } 986 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) { 987 assert(!doing_subtype_search(), "must set up a method definer search"); 988 // When looking for unexpected concrete methods, 989 // look beneath expected ones, to see if there are overrides. 990 const bool participants_hide_witnesses = true; 991 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness. 992 if (changes != NULL) { 993 return find_witness_in(*changes, context_type, !participants_hide_witnesses); 994 } else { 995 return find_witness_anywhere(context_type, !participants_hide_witnesses); 996 } 997 } 998 }; 999 1000 #ifndef PRODUCT 1001 static int deps_find_witness_calls = 0; 1002 static int deps_find_witness_steps = 0; 1003 static int deps_find_witness_recursions = 0; 1004 static int deps_find_witness_singles = 0; 1005 static int deps_find_witness_print = 0; // set to -1 to force a final print 1006 static bool count_find_witness_calls() { 1007 if (TraceDependencies || LogCompilation) { 1008 int pcount = deps_find_witness_print + 1; 1009 bool final_stats = (pcount == 0); 1010 bool initial_call = (pcount == 1); 1011 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0); 1012 if (pcount < 0) pcount = 1; // crude overflow protection 1013 deps_find_witness_print = pcount; 1014 if (VerifyDependencies && initial_call) { 1015 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies"); 1016 } 1017 if (occasional_print || final_stats) { 1018 // Every now and then dump a little info about dependency searching. 1019 if (xtty != NULL) { 1020 ttyLocker ttyl; 1021 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'", 1022 deps_find_witness_calls, 1023 deps_find_witness_steps, 1024 deps_find_witness_recursions, 1025 deps_find_witness_singles); 1026 } 1027 if (final_stats || (TraceDependencies && WizardMode)) { 1028 ttyLocker ttyl; 1029 tty->print_cr("Dependency check (find_witness) " 1030 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d", 1031 deps_find_witness_calls, 1032 deps_find_witness_steps, 1033 (double)deps_find_witness_steps / deps_find_witness_calls, 1034 deps_find_witness_recursions, 1035 deps_find_witness_singles); 1036 } 1037 } 1038 return true; 1039 } 1040 return false; 1041 } 1042 #else 1043 #define count_find_witness_calls() (0) 1044 #endif //PRODUCT 1045 1046 1047 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes, 1048 Klass* context_type, 1049 bool participants_hide_witnesses) { 1050 assert(changes.involves_context(context_type), "irrelevant dependency"); 1051 Klass* new_type = changes.new_type(); 1052 1053 (void)count_find_witness_calls(); 1054 NOT_PRODUCT(deps_find_witness_singles++); 1055 1056 // Current thread must be in VM (not native mode, as in CI): 1057 assert(must_be_in_vm(), "raw oops here"); 1058 // Must not move the class hierarchy during this check: 1059 assert_locked_or_safepoint(Compile_lock); 1060 1061 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1062 if (nof_impls > 1) { 1063 // Avoid this case: *I.m > { A.m, C }; B.m > C 1064 // %%% Until this is fixed more systematically, bail out. 1065 // See corresponding comment in find_witness_anywhere. 1066 return context_type; 1067 } 1068 1069 assert(!is_participant(new_type), "only old classes are participants"); 1070 if (participants_hide_witnesses) { 1071 // If the new type is a subtype of a participant, we are done. 1072 for (int i = 0; i < num_participants(); i++) { 1073 Klass* part = participant(i); 1074 if (part == NULL) continue; 1075 assert(changes.involves_context(part) == new_type->is_subtype_of(part), 1076 "correct marking of participants, b/c new_type is unique"); 1077 if (changes.involves_context(part)) { 1078 // new guy is protected from this check by previous participant 1079 return NULL; 1080 } 1081 } 1082 } 1083 1084 if (is_witness(new_type) && 1085 !ignore_witness(new_type)) { 1086 return new_type; 1087 } 1088 1089 return NULL; 1090 } 1091 1092 1093 // Walk hierarchy under a context type, looking for unexpected types. 1094 // Do not report participant types, and recursively walk beneath 1095 // them only if participants_hide_witnesses is false. 1096 // If top_level_call is false, skip testing the context type, 1097 // because the caller has already considered it. 1098 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type, 1099 bool participants_hide_witnesses, 1100 bool top_level_call) { 1101 // Current thread must be in VM (not native mode, as in CI): 1102 assert(must_be_in_vm(), "raw oops here"); 1103 // Must not move the class hierarchy during this check: 1104 assert_locked_or_safepoint(Compile_lock); 1105 1106 bool do_counts = count_find_witness_calls(); 1107 1108 // Check the root of the sub-hierarchy first. 1109 if (top_level_call) { 1110 if (do_counts) { 1111 NOT_PRODUCT(deps_find_witness_calls++); 1112 NOT_PRODUCT(deps_find_witness_steps++); 1113 } 1114 if (is_participant(context_type)) { 1115 if (participants_hide_witnesses) return NULL; 1116 // else fall through to search loop... 1117 } else if (is_witness(context_type) && !ignore_witness(context_type)) { 1118 // The context is an abstract class or interface, to start with. 1119 return context_type; 1120 } 1121 } 1122 1123 // Now we must check each implementor and each subclass. 1124 // Use a short worklist to avoid blowing the stack. 1125 // Each worklist entry is a *chain* of subklass siblings to process. 1126 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit 1127 Klass* chains[CHAINMAX]; 1128 int chaini = 0; // index into worklist 1129 Klass* chain; // scratch variable 1130 #define ADD_SUBCLASS_CHAIN(k) { \ 1131 assert(chaini < CHAINMAX, "oob"); \ 1132 chain = k->subklass(); \ 1133 if (chain != NULL) chains[chaini++] = chain; } 1134 1135 // Look for non-abstract subclasses. 1136 // (Note: Interfaces do not have subclasses.) 1137 ADD_SUBCLASS_CHAIN(context_type); 1138 1139 // If it is an interface, search its direct implementors. 1140 // (Their subclasses are additional indirect implementors. 1141 // See InstanceKlass::add_implementor.) 1142 // (Note: nof_implementors is always zero for non-interfaces.) 1143 if (top_level_call) { 1144 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1145 if (nof_impls > 1) { 1146 // Avoid this case: *I.m > { A.m, C }; B.m > C 1147 // Here, I.m has 2 concrete implementations, but m appears unique 1148 // as A.m, because the search misses B.m when checking C. 1149 // The inherited method B.m was getting missed by the walker 1150 // when interface 'I' was the starting point. 1151 // %%% Until this is fixed more systematically, bail out. 1152 // (Old CHA had the same limitation.) 1153 return context_type; 1154 } 1155 if (nof_impls > 0) { 1156 Klass* impl = InstanceKlass::cast(context_type)->implementor(); 1157 assert(impl != NULL, "just checking"); 1158 // If impl is the same as the context_type, then more than one 1159 // implementor has seen. No exact info in this case. 1160 if (impl == context_type) { 1161 return context_type; // report an inexact witness to this sad affair 1162 } 1163 if (do_counts) 1164 { NOT_PRODUCT(deps_find_witness_steps++); } 1165 if (is_participant(impl)) { 1166 if (!participants_hide_witnesses) { 1167 ADD_SUBCLASS_CHAIN(impl); 1168 } 1169 } else if (is_witness(impl) && !ignore_witness(impl)) { 1170 return impl; 1171 } else { 1172 ADD_SUBCLASS_CHAIN(impl); 1173 } 1174 } 1175 } 1176 1177 // Recursively process each non-trivial sibling chain. 1178 while (chaini > 0) { 1179 Klass* chain = chains[--chaini]; 1180 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) { 1181 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); } 1182 if (is_participant(sub)) { 1183 if (participants_hide_witnesses) continue; 1184 // else fall through to process this guy's subclasses 1185 } else if (is_witness(sub) && !ignore_witness(sub)) { 1186 return sub; 1187 } 1188 if (chaini < (VerifyDependencies? 2: CHAINMAX)) { 1189 // Fast path. (Partially disabled if VerifyDependencies.) 1190 ADD_SUBCLASS_CHAIN(sub); 1191 } else { 1192 // Worklist overflow. Do a recursive call. Should be rare. 1193 // The recursive call will have its own worklist, of course. 1194 // (Note that sub has already been tested, so that there is 1195 // no need for the recursive call to re-test. That's handy, 1196 // since the recursive call sees sub as the context_type.) 1197 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); } 1198 Klass* witness = find_witness_anywhere(sub, 1199 participants_hide_witnesses, 1200 /*top_level_call=*/ false); 1201 if (witness != NULL) return witness; 1202 } 1203 } 1204 } 1205 1206 // No witness found. The dependency remains unbroken. 1207 return NULL; 1208 #undef ADD_SUBCLASS_CHAIN 1209 } 1210 1211 1212 bool Dependencies::is_concrete_klass(Klass* k) { 1213 if (k->is_abstract()) return false; 1214 // %%% We could treat classes which are concrete but 1215 // have not yet been instantiated as virtually abstract. 1216 // This would require a deoptimization barrier on first instantiation. 1217 //if (k->is_not_instantiated()) return false; 1218 return true; 1219 } 1220 1221 bool Dependencies::is_concrete_method(Method* m, Klass * k) { 1222 // NULL is not a concrete method, 1223 // statics are irrelevant to virtual call sites, 1224 // abstract methods are not concrete, 1225 // overpass (error) methods are not concrete if k is abstract 1226 // 1227 // note "true" is conservative answer -- 1228 // overpass clause is false if k == NULL, implies return true if 1229 // answer depends on overpass clause. 1230 return ! ( m == NULL || m -> is_static() || m -> is_abstract() || 1231 m->is_overpass() && k != NULL && k -> is_abstract() ); 1232 } 1233 1234 1235 Klass* Dependencies::find_finalizable_subclass(Klass* k) { 1236 if (k->is_interface()) return NULL; 1237 if (k->has_finalizer()) return k; 1238 k = k->subklass(); 1239 while (k != NULL) { 1240 Klass* result = find_finalizable_subclass(k); 1241 if (result != NULL) return result; 1242 k = k->next_sibling(); 1243 } 1244 return NULL; 1245 } 1246 1247 1248 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) { 1249 if (k->is_abstract()) return false; 1250 // We could also return false if k does not yet appear to be 1251 // instantiated, if the VM version supports this distinction also. 1252 //if (k->is_not_instantiated()) return false; 1253 return true; 1254 } 1255 1256 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) { 1257 return k->has_finalizable_subclass(); 1258 } 1259 1260 1261 // Any use of the contents (bytecodes) of a method must be 1262 // marked by an "evol_method" dependency, if those contents 1263 // can change. (Note: A method is always dependent on itself.) 1264 Klass* Dependencies::check_evol_method(Method* m) { 1265 assert(must_be_in_vm(), "raw oops here"); 1266 // Did somebody do a JVMTI RedefineClasses while our backs were turned? 1267 // Or is there a now a breakpoint? 1268 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.) 1269 if (m->is_old() 1270 || m->number_of_breakpoints() > 0) { 1271 return m->method_holder(); 1272 } else { 1273 return NULL; 1274 } 1275 } 1276 1277 // This is a strong assertion: It is that the given type 1278 // has no subtypes whatever. It is most useful for 1279 // optimizing checks on reflected types or on array types. 1280 // (Checks on types which are derived from real instances 1281 // can be optimized more strongly than this, because we 1282 // know that the checked type comes from a concrete type, 1283 // and therefore we can disregard abstract types.) 1284 Klass* Dependencies::check_leaf_type(Klass* ctxk) { 1285 assert(must_be_in_vm(), "raw oops here"); 1286 assert_locked_or_safepoint(Compile_lock); 1287 InstanceKlass* ctx = InstanceKlass::cast(ctxk); 1288 Klass* sub = ctx->subklass(); 1289 if (sub != NULL) { 1290 return sub; 1291 } else if (ctx->nof_implementors() != 0) { 1292 // if it is an interface, it must be unimplemented 1293 // (if it is not an interface, nof_implementors is always zero) 1294 Klass* impl = ctx->implementor(); 1295 assert(impl != NULL, "must be set"); 1296 return impl; 1297 } else { 1298 return NULL; 1299 } 1300 } 1301 1302 // Test the assertion that conck is the only concrete subtype* of ctxk. 1303 // The type conck itself is allowed to have have further concrete subtypes. 1304 // This allows the compiler to narrow occurrences of ctxk by conck, 1305 // when dealing with the types of actual instances. 1306 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk, 1307 Klass* conck, 1308 KlassDepChange* changes) { 1309 ClassHierarchyWalker wf(conck); 1310 return wf.find_witness_subtype(ctxk, changes); 1311 } 1312 1313 // If a non-concrete class has no concrete subtypes, it is not (yet) 1314 // instantiatable. This can allow the compiler to make some paths go 1315 // dead, if they are gated by a test of the type. 1316 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk, 1317 KlassDepChange* changes) { 1318 // Find any concrete subtype, with no participants: 1319 ClassHierarchyWalker wf; 1320 return wf.find_witness_subtype(ctxk, changes); 1321 } 1322 1323 1324 // If a concrete class has no concrete subtypes, it can always be 1325 // exactly typed. This allows the use of a cheaper type test. 1326 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk, 1327 KlassDepChange* changes) { 1328 // Find any concrete subtype, with only the ctxk as participant: 1329 ClassHierarchyWalker wf(ctxk); 1330 return wf.find_witness_subtype(ctxk, changes); 1331 } 1332 1333 1334 // Find the unique concrete proper subtype of ctxk, or NULL if there 1335 // is more than one concrete proper subtype. If there are no concrete 1336 // proper subtypes, return ctxk itself, whether it is concrete or not. 1337 // The returned subtype is allowed to have have further concrete subtypes. 1338 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }. 1339 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) { 1340 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking. 1341 wf.record_witnesses(1); // Record one other witness when walking. 1342 Klass* wit = wf.find_witness_subtype(ctxk); 1343 if (wit != NULL) return NULL; // Too many witnesses. 1344 Klass* conck = wf.participant(0); 1345 if (conck == NULL) { 1346 #ifndef PRODUCT 1347 // Make sure the dependency mechanism will pass this discovery: 1348 if (VerifyDependencies) { 1349 // Turn off dependency tracing while actually testing deps. 1350 FlagSetting fs(TraceDependencies, false); 1351 if (!Dependencies::is_concrete_klass(ctxk)) { 1352 guarantee(NULL == 1353 (void *)check_abstract_with_no_concrete_subtype(ctxk), 1354 "verify dep."); 1355 } else { 1356 guarantee(NULL == 1357 (void *)check_concrete_with_no_concrete_subtype(ctxk), 1358 "verify dep."); 1359 } 1360 } 1361 #endif //PRODUCT 1362 return ctxk; // Return ctxk as a flag for "no subtypes". 1363 } else { 1364 #ifndef PRODUCT 1365 // Make sure the dependency mechanism will pass this discovery: 1366 if (VerifyDependencies) { 1367 // Turn off dependency tracing while actually testing deps. 1368 FlagSetting fs(TraceDependencies, false); 1369 if (!Dependencies::is_concrete_klass(ctxk)) { 1370 guarantee(NULL == (void *) 1371 check_abstract_with_unique_concrete_subtype(ctxk, conck), 1372 "verify dep."); 1373 } 1374 } 1375 #endif //PRODUCT 1376 return conck; 1377 } 1378 } 1379 1380 // Test the assertion that the k[12] are the only concrete subtypes of ctxk, 1381 // except possibly for further subtypes of k[12] themselves. 1382 // The context type must be abstract. The types k1 and k2 are themselves 1383 // allowed to have further concrete subtypes. 1384 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes( 1385 Klass* ctxk, 1386 Klass* k1, 1387 Klass* k2, 1388 KlassDepChange* changes) { 1389 ClassHierarchyWalker wf; 1390 wf.add_participant(k1); 1391 wf.add_participant(k2); 1392 return wf.find_witness_subtype(ctxk, changes); 1393 } 1394 1395 // Search ctxk for concrete implementations. If there are klen or fewer, 1396 // pack them into the given array and return the number. 1397 // Otherwise, return -1, meaning the given array would overflow. 1398 // (Note that a return of 0 means there are exactly no concrete subtypes.) 1399 // In this search, if ctxk is concrete, it will be reported alone. 1400 // For any type CC reported, no proper subtypes of CC will be reported. 1401 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk, 1402 int klen, 1403 Klass* karray[]) { 1404 ClassHierarchyWalker wf; 1405 wf.record_witnesses(klen); 1406 Klass* wit = wf.find_witness_subtype(ctxk); 1407 if (wit != NULL) return -1; // Too many witnesses. 1408 int num = wf.num_participants(); 1409 assert(num <= klen, "oob"); 1410 // Pack the result array with the good news. 1411 for (int i = 0; i < num; i++) 1412 karray[i] = wf.participant(i); 1413 #ifndef PRODUCT 1414 // Make sure the dependency mechanism will pass this discovery: 1415 if (VerifyDependencies) { 1416 // Turn off dependency tracing while actually testing deps. 1417 FlagSetting fs(TraceDependencies, false); 1418 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) { 1419 case -1: // ctxk was itself concrete 1420 guarantee(num == 1 && karray[0] == ctxk, "verify dep."); 1421 break; 1422 case 0: 1423 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk), 1424 "verify dep."); 1425 break; 1426 case 1: 1427 guarantee(NULL == (void *) 1428 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]), 1429 "verify dep."); 1430 break; 1431 case 2: 1432 guarantee(NULL == (void *) 1433 check_abstract_with_exclusive_concrete_subtypes(ctxk, 1434 karray[0], 1435 karray[1]), 1436 "verify dep."); 1437 break; 1438 default: 1439 ShouldNotReachHere(); // klen > 2 yet supported 1440 } 1441 } 1442 #endif //PRODUCT 1443 return num; 1444 } 1445 1446 // If a class (or interface) has a unique concrete method uniqm, return NULL. 1447 // Otherwise, return a class that contains an interfering method. 1448 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm, 1449 KlassDepChange* changes) { 1450 // Here is a missing optimization: If uniqm->is_final(), 1451 // we don't really need to search beneath it for overrides. 1452 // This is probably not important, since we don't use dependencies 1453 // to track final methods. (They can't be "definalized".) 1454 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm); 1455 return wf.find_witness_definer(ctxk, changes); 1456 } 1457 1458 // Find the set of all non-abstract methods under ctxk that match m. 1459 // (The method m must be defined or inherited in ctxk.) 1460 // Include m itself in the set, unless it is abstract. 1461 // If this set has exactly one element, return that element. 1462 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) { 1463 // Return NULL if m is marked old; must have been a redefined method. 1464 if (m->is_old()) { 1465 return NULL; 1466 } 1467 ClassHierarchyWalker wf(m); 1468 assert(wf.check_method_context(ctxk, m), "proper context"); 1469 wf.record_witnesses(1); 1470 Klass* wit = wf.find_witness_definer(ctxk); 1471 if (wit != NULL) return NULL; // Too many witnesses. 1472 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0. 1473 if (Dependencies::is_concrete_method(m, ctxk)) { 1474 if (fm == NULL) { 1475 // It turns out that m was always the only implementation. 1476 fm = m; 1477 } else if (fm != m) { 1478 // Two conflicting implementations after all. 1479 // (This can happen if m is inherited into ctxk and fm overrides it.) 1480 return NULL; 1481 } 1482 } 1483 #ifndef PRODUCT 1484 // Make sure the dependency mechanism will pass this discovery: 1485 if (VerifyDependencies && fm != NULL) { 1486 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm), 1487 "verify dep."); 1488 } 1489 #endif //PRODUCT 1490 return fm; 1491 } 1492 1493 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk, 1494 Method* m1, 1495 Method* m2, 1496 KlassDepChange* changes) { 1497 ClassHierarchyWalker wf(m1); 1498 wf.add_participant(m1->method_holder()); 1499 wf.add_participant(m2->method_holder()); 1500 return wf.find_witness_definer(ctxk, changes); 1501 } 1502 1503 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) { 1504 Klass* search_at = ctxk; 1505 if (changes != NULL) 1506 search_at = changes->new_type(); // just look at the new bit 1507 return find_finalizable_subclass(search_at); 1508 } 1509 1510 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) { 1511 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity"); 1512 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity"); 1513 if (changes == NULL) { 1514 // Validate all CallSites 1515 if (java_lang_invoke_CallSite::target(call_site) != method_handle) 1516 return call_site->klass(); // assertion failed 1517 } else { 1518 // Validate the given CallSite 1519 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) { 1520 assert(method_handle != changes->method_handle(), "must be"); 1521 return call_site->klass(); // assertion failed 1522 } 1523 } 1524 return NULL; // assertion still valid 1525 } 1526 1527 1528 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) { 1529 if (witness != NULL) { 1530 if (TraceDependencies) { 1531 print_dependency(witness, /*verbose=*/ true); 1532 } 1533 // The following is a no-op unless logging is enabled: 1534 log_dependency(witness); 1535 } 1536 } 1537 1538 1539 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) { 1540 assert_locked_or_safepoint(Compile_lock); 1541 Dependencies::check_valid_dependency_type(type()); 1542 1543 Klass* witness = NULL; 1544 switch (type()) { 1545 case evol_method: 1546 witness = check_evol_method(method_argument(0)); 1547 break; 1548 case leaf_type: 1549 witness = check_leaf_type(context_type()); 1550 break; 1551 case abstract_with_unique_concrete_subtype: 1552 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes); 1553 break; 1554 case abstract_with_no_concrete_subtype: 1555 witness = check_abstract_with_no_concrete_subtype(context_type(), changes); 1556 break; 1557 case concrete_with_no_concrete_subtype: 1558 witness = check_concrete_with_no_concrete_subtype(context_type(), changes); 1559 break; 1560 case unique_concrete_method: 1561 witness = check_unique_concrete_method(context_type(), method_argument(1), changes); 1562 break; 1563 case abstract_with_exclusive_concrete_subtypes_2: 1564 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes); 1565 break; 1566 case exclusive_concrete_methods_2: 1567 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes); 1568 break; 1569 case no_finalizable_subclasses: 1570 witness = check_has_no_finalizable_subclasses(context_type(), changes); 1571 break; 1572 default: 1573 witness = NULL; 1574 break; 1575 } 1576 trace_and_log_witness(witness); 1577 return witness; 1578 } 1579 1580 1581 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) { 1582 assert_locked_or_safepoint(Compile_lock); 1583 Dependencies::check_valid_dependency_type(type()); 1584 1585 Klass* witness = NULL; 1586 switch (type()) { 1587 case call_site_target_value: 1588 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes); 1589 break; 1590 default: 1591 witness = NULL; 1592 break; 1593 } 1594 trace_and_log_witness(witness); 1595 return witness; 1596 } 1597 1598 1599 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) { 1600 // Handle klass dependency 1601 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type())) 1602 return check_klass_dependency(changes.as_klass_change()); 1603 1604 // Handle CallSite dependency 1605 if (changes.is_call_site_change()) 1606 return check_call_site_dependency(changes.as_call_site_change()); 1607 1608 // irrelevant dependency; skip it 1609 return NULL; 1610 } 1611 1612 1613 void DepChange::print() { 1614 int nsup = 0, nint = 0; 1615 for (ContextStream str(*this); str.next(); ) { 1616 Klass* k = str.klass(); 1617 switch (str.change_type()) { 1618 case Change_new_type: 1619 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name()); 1620 break; 1621 case Change_new_sub: 1622 if (!WizardMode) { 1623 ++nsup; 1624 } else { 1625 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name()); 1626 } 1627 break; 1628 case Change_new_impl: 1629 if (!WizardMode) { 1630 ++nint; 1631 } else { 1632 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name()); 1633 } 1634 break; 1635 } 1636 } 1637 if (nsup + nint != 0) { 1638 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint); 1639 } 1640 } 1641 1642 void DepChange::ContextStream::start() { 1643 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL; 1644 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass); 1645 _klass = new_type; 1646 _ti_base = NULL; 1647 _ti_index = 0; 1648 _ti_limit = 0; 1649 } 1650 1651 bool DepChange::ContextStream::next() { 1652 switch (_change_type) { 1653 case Start_Klass: // initial state; _klass is the new type 1654 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces(); 1655 _ti_index = 0; 1656 _change_type = Change_new_type; 1657 return true; 1658 case Change_new_type: 1659 // fall through: 1660 _change_type = Change_new_sub; 1661 case Change_new_sub: 1662 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277 1663 { 1664 _klass = InstanceKlass::cast(_klass)->super(); 1665 if (_klass != NULL) { 1666 return true; 1667 } 1668 } 1669 // else set up _ti_limit and fall through: 1670 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length(); 1671 _change_type = Change_new_impl; 1672 case Change_new_impl: 1673 if (_ti_index < _ti_limit) { 1674 _klass = _ti_base->at(_ti_index++); 1675 return true; 1676 } 1677 // fall through: 1678 _change_type = NO_CHANGE; // iterator is exhausted 1679 case NO_CHANGE: 1680 break; 1681 default: 1682 ShouldNotReachHere(); 1683 } 1684 return false; 1685 } 1686 1687 void KlassDepChange::initialize() { 1688 // entire transaction must be under this lock: 1689 assert_lock_strong(Compile_lock); 1690 1691 // Mark all dependee and all its superclasses 1692 // Mark transitive interfaces 1693 for (ContextStream str(*this); str.next(); ) { 1694 Klass* d = str.klass(); 1695 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking"); 1696 InstanceKlass::cast(d)->set_is_marked_dependent(true); 1697 } 1698 } 1699 1700 KlassDepChange::~KlassDepChange() { 1701 // Unmark all dependee and all its superclasses 1702 // Unmark transitive interfaces 1703 for (ContextStream str(*this); str.next(); ) { 1704 Klass* d = str.klass(); 1705 InstanceKlass::cast(d)->set_is_marked_dependent(false); 1706 } 1707 } 1708 1709 bool KlassDepChange::involves_context(Klass* k) { 1710 if (k == NULL || !k->oop_is_instance()) { 1711 return false; 1712 } 1713 InstanceKlass* ik = InstanceKlass::cast(k); 1714 bool is_contained = ik->is_marked_dependent(); 1715 assert(is_contained == new_type()->is_subtype_of(k), 1716 "correct marking of potential context types"); 1717 return is_contained; 1718 } 1719 1720 #ifndef PRODUCT 1721 void Dependencies::print_statistics() { 1722 if (deps_find_witness_print != 0) { 1723 // Call one final time, to flush out the data. 1724 deps_find_witness_print = -1; 1725 count_find_witness_calls(); 1726 } 1727 } 1728 #endif