1 /* 2 * Copyright (c) 2005, 2013, 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 "utilities/copy.hpp" 36 37 38 #ifdef ASSERT 39 static bool must_be_in_vm() { 40 Thread* thread = Thread::current(); 41 if (thread->is_Java_thread()) 42 return ((JavaThread*)thread)->thread_state() == _thread_in_vm; 43 else 44 return true; //something like this: thread->is_VM_thread(); 45 } 46 #endif //ASSERT 47 48 void Dependencies::initialize(ciEnv* env) { 49 Arena* arena = env->arena(); 50 _oop_recorder = env->oop_recorder(); 51 _log = env->log(); 52 _dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0); 53 DEBUG_ONLY(_deps[end_marker] = NULL); 54 for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) { 55 _deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0); 56 } 57 _content_bytes = NULL; 58 _size_in_bytes = (size_t)-1; 59 60 assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity"); 61 } 62 63 void Dependencies::assert_evol_method(ciMethod* m) { 64 assert_common_1(evol_method, m); 65 } 66 67 void Dependencies::assert_leaf_type(ciKlass* ctxk) { 68 if (ctxk->is_array_klass()) { 69 // As a special case, support this assertion on an array type, 70 // which reduces to an assertion on its element type. 71 // Note that this cannot be done with assertions that 72 // relate to concreteness or abstractness. 73 ciType* elemt = ctxk->as_array_klass()->base_element_type(); 74 if (!elemt->is_instance_klass()) return; // Ex: int[][] 75 ctxk = elemt->as_instance_klass(); 76 //if (ctxk->is_final()) return; // Ex: String[][] 77 } 78 check_ctxk(ctxk); 79 assert_common_1(leaf_type, ctxk); 80 } 81 82 void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) { 83 check_ctxk_abstract(ctxk); 84 assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck); 85 } 86 87 void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) { 88 check_ctxk_abstract(ctxk); 89 assert_common_1(abstract_with_no_concrete_subtype, ctxk); 90 } 91 92 void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) { 93 check_ctxk_concrete(ctxk); 94 assert_common_1(concrete_with_no_concrete_subtype, ctxk); 95 } 96 97 void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) { 98 check_ctxk(ctxk); 99 assert_common_2(unique_concrete_method, ctxk, uniqm); 100 } 101 102 void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) { 103 check_ctxk(ctxk); 104 assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2); 105 } 106 107 void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) { 108 check_ctxk(ctxk); 109 assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2); 110 } 111 112 void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) { 113 check_ctxk(ctxk); 114 assert_common_1(no_finalizable_subclasses, ctxk); 115 } 116 117 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) { 118 check_ctxk(call_site->klass()); 119 assert_common_2(call_site_target_value, call_site, method_handle); 120 } 121 122 // Helper function. If we are adding a new dep. under ctxk2, 123 // try to find an old dep. under a broader* ctxk1. If there is 124 // 125 bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps, 126 int ctxk_i, ciKlass* ctxk2) { 127 ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass(); 128 if (ctxk2->is_subtype_of(ctxk1)) { 129 return true; // success, and no need to change 130 } else if (ctxk1->is_subtype_of(ctxk2)) { 131 // new context class fully subsumes previous one 132 deps->at_put(ctxk_i, ctxk2); 133 return true; 134 } else { 135 return false; 136 } 137 } 138 139 void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) { 140 assert(dep_args(dept) == 1, "sanity"); 141 log_dependency(dept, x); 142 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 143 144 // see if the same (or a similar) dep is already recorded 145 if (note_dep_seen(dept, x)) { 146 assert(deps->find(x) >= 0, "sanity"); 147 } else { 148 deps->append(x); 149 } 150 } 151 152 void Dependencies::assert_common_2(DepType dept, 153 ciBaseObject* x0, ciBaseObject* x1) { 154 assert(dep_args(dept) == 2, "sanity"); 155 log_dependency(dept, x0, x1); 156 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 157 158 // see if the same (or a similar) dep is already recorded 159 bool has_ctxk = has_explicit_context_arg(dept); 160 if (has_ctxk) { 161 assert(dep_context_arg(dept) == 0, "sanity"); 162 if (note_dep_seen(dept, x1)) { 163 // look in this bucket for redundant assertions 164 const int stride = 2; 165 for (int i = deps->length(); (i -= stride) >= 0; ) { 166 ciBaseObject* y1 = deps->at(i+1); 167 if (x1 == y1) { // same subject; check the context 168 if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) { 169 return; 170 } 171 } 172 } 173 } 174 } else { 175 assert(dep_implicit_context_arg(dept) == 0, "sanity"); 176 if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) { 177 // look in this bucket for redundant assertions 178 const int stride = 2; 179 for (int i = deps->length(); (i -= stride) >= 0; ) { 180 ciBaseObject* y0 = deps->at(i+0); 181 ciBaseObject* y1 = deps->at(i+1); 182 if (x0 == y0 && x1 == y1) { 183 return; 184 } 185 } 186 } 187 } 188 189 // append the assertion in the correct bucket: 190 deps->append(x0); 191 deps->append(x1); 192 } 193 194 void Dependencies::assert_common_3(DepType dept, 195 ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) { 196 assert(dep_context_arg(dept) == 0, "sanity"); 197 assert(dep_args(dept) == 3, "sanity"); 198 log_dependency(dept, ctxk, x, x2); 199 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 200 201 // try to normalize an unordered pair: 202 bool swap = false; 203 switch (dept) { 204 case abstract_with_exclusive_concrete_subtypes_2: 205 swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk); 206 break; 207 case exclusive_concrete_methods_2: 208 swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk); 209 break; 210 } 211 if (swap) { ciBaseObject* t = x; x = x2; x2 = t; } 212 213 // see if the same (or a similar) dep is already recorded 214 if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) { 215 // look in this bucket for redundant assertions 216 const int stride = 3; 217 for (int i = deps->length(); (i -= stride) >= 0; ) { 218 ciBaseObject* y = deps->at(i+1); 219 ciBaseObject* y2 = deps->at(i+2); 220 if (x == y && x2 == y2) { // same subjects; check the context 221 if (maybe_merge_ctxk(deps, i+0, ctxk)) { 222 return; 223 } 224 } 225 } 226 } 227 // append the assertion in the correct bucket: 228 deps->append(ctxk); 229 deps->append(x); 230 deps->append(x2); 231 } 232 233 /// Support for encoding dependencies into an nmethod: 234 235 void Dependencies::copy_to(nmethod* nm) { 236 address beg = nm->dependencies_begin(); 237 address end = nm->dependencies_end(); 238 guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing"); 239 Copy::disjoint_words((HeapWord*) content_bytes(), 240 (HeapWord*) beg, 241 size_in_bytes() / sizeof(HeapWord)); 242 assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words"); 243 } 244 245 static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) { 246 for (int i = 0; i < narg; i++) { 247 int diff = p1[i]->ident() - p2[i]->ident(); 248 if (diff != 0) return diff; 249 } 250 return 0; 251 } 252 static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2) 253 { return sort_dep(p1, p2, 1); } 254 static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2) 255 { return sort_dep(p1, p2, 2); } 256 static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2) 257 { return sort_dep(p1, p2, 3); } 258 259 void Dependencies::sort_all_deps() { 260 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 261 DepType dept = (DepType)deptv; 262 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 263 if (deps->length() <= 1) continue; 264 switch (dep_args(dept)) { 265 case 1: deps->sort(sort_dep_arg_1, 1); break; 266 case 2: deps->sort(sort_dep_arg_2, 2); break; 267 case 3: deps->sort(sort_dep_arg_3, 3); break; 268 default: ShouldNotReachHere(); 269 } 270 } 271 } 272 273 size_t Dependencies::estimate_size_in_bytes() { 274 size_t est_size = 100; 275 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 276 DepType dept = (DepType)deptv; 277 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 278 est_size += deps->length()*2; // tags and argument(s) 279 } 280 return est_size; 281 } 282 283 ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) { 284 switch (dept) { 285 case abstract_with_exclusive_concrete_subtypes_2: 286 return x->as_metadata()->as_klass(); 287 case unique_concrete_method: 288 case exclusive_concrete_methods_2: 289 return x->as_metadata()->as_method()->holder(); 290 } 291 return NULL; // let NULL be NULL 292 } 293 294 Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) { 295 assert(must_be_in_vm(), "raw oops here"); 296 switch (dept) { 297 case abstract_with_exclusive_concrete_subtypes_2: 298 assert(x->is_klass(), "sanity"); 299 return (Klass*) x; 300 case unique_concrete_method: 301 case exclusive_concrete_methods_2: 302 assert(x->is_method(), "sanity"); 303 return ((Method*)x)->method_holder(); 304 } 305 return NULL; // let NULL be NULL 306 } 307 308 void Dependencies::encode_content_bytes() { 309 sort_all_deps(); 310 311 // cast is safe, no deps can overflow INT_MAX 312 CompressedWriteStream bytes((int)estimate_size_in_bytes()); 313 314 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 315 DepType dept = (DepType)deptv; 316 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 317 if (deps->length() == 0) continue; 318 int stride = dep_args(dept); 319 int ctxkj = dep_context_arg(dept); // -1 if no context arg 320 assert(stride > 0, "sanity"); 321 for (int i = 0; i < deps->length(); i += stride) { 322 jbyte code_byte = (jbyte)dept; 323 int skipj = -1; 324 if (ctxkj >= 0 && ctxkj+1 < stride) { 325 ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass(); 326 ciBaseObject* x = deps->at(i+ctxkj+1); // following argument 327 if (ctxk == ctxk_encoded_as_null(dept, x)) { 328 skipj = ctxkj; // we win: maybe one less oop to keep track of 329 code_byte |= default_context_type_bit; 330 } 331 } 332 bytes.write_byte(code_byte); 333 for (int j = 0; j < stride; j++) { 334 if (j == skipj) continue; 335 ciBaseObject* v = deps->at(i+j); 336 int idx; 337 if (v->is_object()) { 338 idx = _oop_recorder->find_index(v->as_object()->constant_encoding()); 339 } else { 340 ciMetadata* meta = v->as_metadata(); 341 idx = _oop_recorder->find_index(meta->constant_encoding()); 342 } 343 bytes.write_int(idx); 344 } 345 } 346 } 347 348 // write a sentinel byte to mark the end 349 bytes.write_byte(end_marker); 350 351 // round it out to a word boundary 352 while (bytes.position() % sizeof(HeapWord) != 0) { 353 bytes.write_byte(end_marker); 354 } 355 356 // check whether the dept byte encoding really works 357 assert((jbyte)default_context_type_bit != 0, "byte overflow"); 358 359 _content_bytes = bytes.buffer(); 360 _size_in_bytes = bytes.position(); 361 } 362 363 364 const char* Dependencies::_dep_name[TYPE_LIMIT] = { 365 "end_marker", 366 "evol_method", 367 "leaf_type", 368 "abstract_with_unique_concrete_subtype", 369 "abstract_with_no_concrete_subtype", 370 "concrete_with_no_concrete_subtype", 371 "unique_concrete_method", 372 "abstract_with_exclusive_concrete_subtypes_2", 373 "exclusive_concrete_methods_2", 374 "no_finalizable_subclasses", 375 "call_site_target_value" 376 }; 377 378 int Dependencies::_dep_args[TYPE_LIMIT] = { 379 -1,// end_marker 380 1, // evol_method m 381 1, // leaf_type ctxk 382 2, // abstract_with_unique_concrete_subtype ctxk, k 383 1, // abstract_with_no_concrete_subtype ctxk 384 1, // concrete_with_no_concrete_subtype ctxk 385 2, // unique_concrete_method ctxk, m 386 3, // unique_concrete_subtypes_2 ctxk, k1, k2 387 3, // unique_concrete_methods_2 ctxk, m1, m2 388 1, // no_finalizable_subclasses ctxk 389 2 // call_site_target_value call_site, method_handle 390 }; 391 392 const char* Dependencies::dep_name(Dependencies::DepType dept) { 393 if (!dept_in_mask(dept, all_types)) return "?bad-dep?"; 394 return _dep_name[dept]; 395 } 396 397 int Dependencies::dep_args(Dependencies::DepType dept) { 398 if (!dept_in_mask(dept, all_types)) return -1; 399 return _dep_args[dept]; 400 } 401 402 void Dependencies::check_valid_dependency_type(DepType dept) { 403 guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, err_msg("invalid dependency type: %d", (int) dept)); 404 } 405 406 // for the sake of the compiler log, print out current dependencies: 407 void Dependencies::log_all_dependencies() { 408 if (log() == NULL) return; 409 ciBaseObject* args[max_arg_count]; 410 for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) { 411 DepType dept = (DepType)deptv; 412 GrowableArray<ciBaseObject*>* deps = _deps[dept]; 413 if (deps->length() == 0) continue; 414 int stride = dep_args(dept); 415 for (int i = 0; i < deps->length(); i += stride) { 416 for (int j = 0; j < stride; j++) { 417 // flush out the identities before printing 418 args[j] = deps->at(i+j); 419 } 420 write_dependency_to(log(), dept, stride, args); 421 } 422 } 423 } 424 425 void Dependencies::write_dependency_to(CompileLog* log, 426 DepType dept, 427 int nargs, DepArgument args[], 428 Klass* witness) { 429 if (log == NULL) { 430 return; 431 } 432 ciEnv* env = ciEnv::current(); 433 ciBaseObject* ciargs[max_arg_count]; 434 assert(nargs <= max_arg_count, "oob"); 435 for (int j = 0; j < nargs; j++) { 436 if (args[j].is_oop()) { 437 ciargs[j] = env->get_object(args[j].oop_value()); 438 } else { 439 ciargs[j] = env->get_metadata(args[j].metadata_value()); 440 } 441 } 442 Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness); 443 } 444 445 void Dependencies::write_dependency_to(CompileLog* log, 446 DepType dept, 447 int nargs, ciBaseObject* args[], 448 Klass* witness) { 449 if (log == NULL) return; 450 assert(nargs <= max_arg_count, "oob"); 451 int argids[max_arg_count]; 452 int ctxkj = dep_context_arg(dept); // -1 if no context arg 453 int j; 454 for (j = 0; j < nargs; j++) { 455 if (args[j]->is_object()) { 456 argids[j] = log->identify(args[j]->as_object()); 457 } else { 458 argids[j] = log->identify(args[j]->as_metadata()); 459 } 460 } 461 if (witness != NULL) { 462 log->begin_elem("dependency_failed"); 463 } else { 464 log->begin_elem("dependency"); 465 } 466 log->print(" type='%s'", dep_name(dept)); 467 if (ctxkj >= 0) { 468 log->print(" ctxk='%d'", argids[ctxkj]); 469 } 470 // write remaining arguments, if any. 471 for (j = 0; j < nargs; j++) { 472 if (j == ctxkj) continue; // already logged 473 if (j == 1) { 474 log->print( " x='%d'", argids[j]); 475 } else { 476 log->print(" x%d='%d'", j, argids[j]); 477 } 478 } 479 if (witness != NULL) { 480 log->object("witness", witness); 481 log->stamp(); 482 } 483 log->end_elem(); 484 } 485 486 void Dependencies::write_dependency_to(xmlStream* xtty, 487 DepType dept, 488 int nargs, DepArgument args[], 489 Klass* witness) { 490 if (xtty == NULL) return; 491 ttyLocker ttyl; 492 int ctxkj = dep_context_arg(dept); // -1 if no context arg 493 if (witness != NULL) { 494 xtty->begin_elem("dependency_failed"); 495 } else { 496 xtty->begin_elem("dependency"); 497 } 498 xtty->print(" type='%s'", dep_name(dept)); 499 if (ctxkj >= 0) { 500 xtty->object("ctxk", args[ctxkj].metadata_value()); 501 } 502 // write remaining arguments, if any. 503 for (int j = 0; j < nargs; j++) { 504 if (j == ctxkj) continue; // already logged 505 if (j == 1) { 506 if (args[j].is_oop()) { 507 xtty->object("x", args[j].oop_value()); 508 } else { 509 xtty->object("x", args[j].metadata_value()); 510 } 511 } else { 512 char xn[10]; sprintf(xn, "x%d", j); 513 if (args[j].is_oop()) { 514 xtty->object(xn, args[j].oop_value()); 515 } else { 516 xtty->object(xn, args[j].metadata_value()); 517 } 518 } 519 } 520 if (witness != NULL) { 521 xtty->object("witness", witness); 522 xtty->stamp(); 523 } 524 xtty->end_elem(); 525 } 526 527 void Dependencies::print_dependency(DepType dept, int nargs, DepArgument args[], 528 Klass* witness) { 529 ResourceMark rm; 530 ttyLocker ttyl; // keep the following output all in one block 531 tty->print_cr("%s of type %s", 532 (witness == NULL)? "Dependency": "Failed dependency", 533 dep_name(dept)); 534 // print arguments 535 int ctxkj = dep_context_arg(dept); // -1 if no context arg 536 for (int j = 0; j < nargs; j++) { 537 DepArgument arg = args[j]; 538 bool put_star = false; 539 if (arg.is_null()) continue; 540 const char* what; 541 if (j == ctxkj) { 542 assert(arg.is_metadata(), "must be"); 543 what = "context"; 544 put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value()); 545 } else if (arg.is_method()) { 546 what = "method "; 547 put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value()); 548 } else if (arg.is_klass()) { 549 what = "class "; 550 } else { 551 what = "object "; 552 } 553 tty->print(" %s = %s", what, (put_star? "*": "")); 554 if (arg.is_klass()) 555 tty->print("%s", ((Klass*)arg.metadata_value())->external_name()); 556 else if (arg.is_method()) 557 ((Method*)arg.metadata_value())->print_value(); 558 else 559 ShouldNotReachHere(); // Provide impl for this type. 560 tty->cr(); 561 } 562 if (witness != NULL) { 563 bool put_star = !Dependencies::is_concrete_klass(witness); 564 tty->print_cr(" witness = %s%s", 565 (put_star? "*": ""), 566 witness->external_name()); 567 } 568 } 569 570 void Dependencies::DepStream::log_dependency(Klass* witness) { 571 if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime 572 ResourceMark rm; 573 int nargs = argument_count(); 574 DepArgument args[max_arg_count]; 575 for (int j = 0; j < nargs; j++) { 576 if (type() == call_site_target_value) { 577 args[j] = argument_oop(j); 578 } else { 579 args[j] = argument(j); 580 } 581 } 582 if (_deps != NULL && _deps->log() != NULL) { 583 Dependencies::write_dependency_to(_deps->log(), 584 type(), nargs, args, witness); 585 } else { 586 Dependencies::write_dependency_to(xtty, 587 type(), nargs, args, witness); 588 } 589 } 590 591 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) { 592 int nargs = argument_count(); 593 DepArgument args[max_arg_count]; 594 for (int j = 0; j < nargs; j++) { 595 args[j] = argument(j); 596 } 597 Dependencies::print_dependency(type(), nargs, args, witness); 598 if (verbose) { 599 if (_code != NULL) { 600 tty->print(" code: "); 601 _code->print_value_on(tty); 602 tty->cr(); 603 } 604 } 605 } 606 607 608 /// Dependency stream support (decodes dependencies from an nmethod): 609 610 #ifdef ASSERT 611 void Dependencies::DepStream::initial_asserts(size_t byte_limit) { 612 assert(must_be_in_vm(), "raw oops here"); 613 _byte_limit = byte_limit; 614 _type = (DepType)(end_marker-1); // defeat "already at end" assert 615 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other"); 616 } 617 #endif //ASSERT 618 619 bool Dependencies::DepStream::next() { 620 assert(_type != end_marker, "already at end"); 621 if (_bytes.position() == 0 && _code != NULL 622 && _code->dependencies_size() == 0) { 623 // Method has no dependencies at all. 624 return false; 625 } 626 int code_byte = (_bytes.read_byte() & 0xFF); 627 if (code_byte == end_marker) { 628 DEBUG_ONLY(_type = end_marker); 629 return false; 630 } else { 631 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit); 632 code_byte -= ctxk_bit; 633 DepType dept = (DepType)code_byte; 634 _type = dept; 635 Dependencies::check_valid_dependency_type(dept); 636 int stride = _dep_args[dept]; 637 assert(stride == dep_args(dept), "sanity"); 638 int skipj = -1; 639 if (ctxk_bit != 0) { 640 skipj = 0; // currently the only context argument is at zero 641 assert(skipj == dep_context_arg(dept), "zero arg always ctxk"); 642 } 643 for (int j = 0; j < stride; j++) { 644 _xi[j] = (j == skipj)? 0: _bytes.read_int(); 645 } 646 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns 647 return true; 648 } 649 } 650 651 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) { 652 Metadata* o = NULL; 653 if (_code != NULL) { 654 o = _code->metadata_at(i); 655 } else { 656 o = _deps->oop_recorder()->metadata_at(i); 657 } 658 assert(o == NULL || o->is_metaspace_object(), 659 err_msg("Should be metadata " PTR_FORMAT, o)); 660 return o; 661 } 662 663 inline oop Dependencies::DepStream::recorded_oop_at(int i) { 664 return (_code != NULL) 665 ? _code->oop_at(i) 666 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i)); 667 } 668 669 Metadata* Dependencies::DepStream::argument(int i) { 670 Metadata* result = recorded_metadata_at(argument_index(i)); 671 672 if (result == NULL) { // Explicit context argument can be compressed 673 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 674 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) { 675 result = ctxk_encoded_as_null(type(), argument(ctxkj+1)); 676 } 677 } 678 679 assert(result == NULL || result->is_klass() || result->is_method(), "must be"); 680 return result; 681 } 682 683 uintptr_t Dependencies::DepStream::get_identity_hash(int i) { 684 if (has_oop_argument()) { 685 return argument_oop(i)->identity_hash(); 686 } else { 687 return argument(i)->identity_hash(); 688 } 689 } 690 691 oop Dependencies::DepStream::argument_oop(int i) { 692 oop result = recorded_oop_at(argument_index(i)); 693 assert(result == NULL || result->is_oop(), "must be"); 694 return result; 695 } 696 697 Klass* Dependencies::DepStream::context_type() { 698 assert(must_be_in_vm(), "raw oops here"); 699 700 // Most dependencies have an explicit context type argument. 701 { 702 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 703 if (ctxkj >= 0) { 704 Metadata* k = argument(ctxkj); 705 assert(k != NULL && k->is_klass(), "type check"); 706 return (Klass*)k; 707 } 708 } 709 710 // Some dependencies are using the klass of the first object 711 // argument as implicit context type (e.g. call_site_target_value). 712 { 713 int ctxkj = dep_implicit_context_arg(type()); 714 if (ctxkj >= 0) { 715 Klass* k = argument_oop(ctxkj)->klass(); 716 assert(k != NULL && k->is_klass(), "type check"); 717 return (Klass*) k; 718 } 719 } 720 721 // And some dependencies don't have a context type at all, 722 // e.g. evol_method. 723 return NULL; 724 } 725 726 // ----------------- DependencySignatureBuffer -------------------------------------- 727 DependencySignatureBuffer::DependencySignatureBuffer(Dependencies::DepType type) { 728 _type = type; 729 _root = NULL; 730 } 731 732 /** 733 * Search binary tree recursively. The key is the identity hash of the first or the second dependency 734 * argument. 735 */ 736 DependencySignature* DependencySignatureBuffer::tree_search(DependencySignature* current_node, uintptr_t key) { 737 if (current_node == NULL || key == current_node->key()) { 738 return current_node; 739 } 740 if (key < current_node->key()) { 741 return tree_search(current_node->left(), key); 742 } else { 743 return tree_search(current_node->right(), key); 744 } 745 } 746 747 /** 748 * Returns a buffer that contains the dependency signatures of a particular dependency type. 749 */ 750 DependencySignatureBuffer* DependencySignatureBuffer::buffer(GrowableArray<DependencySignatureBuffer*>* signature_buffers, 751 Dependencies::DepType type) { 752 for (int i = 0; i < signature_buffers->length(); i++) { 753 DependencySignatureBuffer* current = signature_buffers->at(i); 754 if (current->type() == type) { 755 return current; 756 } 757 } 758 759 DependencySignatureBuffer* new_buffer = new DependencySignatureBuffer(type); 760 signature_buffers->append(new_buffer); 761 return new_buffer; 762 } 763 764 /** 765 * To remember already checked dependencies, dependencies are represented as dependency 766 * signatures. A dependency signature consists (i) a type and (ii) the identity hashes 767 * of all arguments. 768 * There is a DependencySignatureBuffer object for each dependency type. As a result, 769 * the lookup that is performed by this function does not have to consider the dependency 770 * type. 771 * Dependency signatures are stored in a binary tree where the key is either the identity hash 772 * of the first argument or the identity hash of the second argument of the dependency. Since 773 * dependencies can have more than one argument, each element of the tree (DependencySignature) 774 * maintains a linked list in which dependency signatures that have the same key but different 775 * argument identity hashes are stored. 776 */ 777 bool DependencySignatureBuffer::contains(DependencySignature* sig) { 778 // Search binary tree 779 DependencySignature* found = tree_search(_root, sig->key()); 780 // Search linked list 781 while (found != NULL) { 782 // Check if arguments are identical. Two dependency signatures are considered 783 // identical, if the type as well as all identity hashes of all arguments are 784 // identical. 785 const int args_count = sig->args_count(); 786 int identical_args = 0; 787 for (int i = 0; i < sig->args_count(); i++) { 788 if (sig->arg(i) == found->arg(i)) { 789 identical_args++; 790 } 791 } 792 if (identical_args == args_count) { 793 return true; 794 } 795 found = found->next(); 796 } 797 return false; 798 } 799 800 /** 801 * Adds element to the binary tree if the binary tree does not contain an element with the specified 802 * key. If the binary tree contains an element of the same key as the element that will be added, the 803 * new dependency signature is appended to the end of a linked list. 804 */ 805 void DependencySignatureBuffer::add(DependencySignature* to_add) { 806 DependencySignature* y = NULL; 807 DependencySignature* x = _root; 808 DependencySignature* z = new DependencySignature(to_add); 809 810 // Insert into binary search tree 811 while (x != NULL) { 812 y = x; 813 // Found key; add to linked list 814 if (z->key() == x->key()) { 815 // Append to end of linked list 816 while (x->next() != NULL) { 817 x = x->next(); 818 } 819 x->set_next(z); 820 return; 821 } else if (z->key() < x->key()) { 822 x = x->left(); 823 } else { 824 x = x->right(); 825 } 826 } 827 // The dependency signature was not found in the tree. Set links of new element. 828 z->set_parent(y); 829 830 if (y == NULL) { 831 _root = z; // tree was empty 832 } else if (z->key() < y->key()) { 833 y->set_left(z); 834 } else { 835 y->set_right(z); 836 } 837 } 838 839 840 /// Checking dependencies: 841 842 // This hierarchy walker inspects subtypes of a given type, 843 // trying to find a "bad" class which breaks a dependency. 844 // Such a class is called a "witness" to the broken dependency. 845 // While searching around, we ignore "participants", which 846 // are already known to the dependency. 847 class ClassHierarchyWalker { 848 public: 849 enum { PARTICIPANT_LIMIT = 3 }; 850 851 private: 852 // optional method descriptor to check for: 853 Symbol* _name; 854 Symbol* _signature; 855 856 // special classes which are not allowed to be witnesses: 857 Klass* _participants[PARTICIPANT_LIMIT+1]; 858 int _num_participants; 859 860 // cache of method lookups 861 Method* _found_methods[PARTICIPANT_LIMIT+1]; 862 863 // if non-zero, tells how many witnesses to convert to participants 864 int _record_witnesses; 865 866 void initialize(Klass* participant) { 867 _record_witnesses = 0; 868 _participants[0] = participant; 869 _found_methods[0] = NULL; 870 _num_participants = 0; 871 if (participant != NULL) { 872 // Terminating NULL. 873 _participants[1] = NULL; 874 _found_methods[1] = NULL; 875 _num_participants = 1; 876 } 877 } 878 879 void initialize_from_method(Method* m) { 880 assert(m != NULL && m->is_method(), "sanity"); 881 _name = m->name(); 882 _signature = m->signature(); 883 } 884 885 public: 886 // The walker is initialized to recognize certain methods and/or types 887 // as friendly participants. 888 ClassHierarchyWalker(Klass* participant, Method* m) { 889 initialize_from_method(m); 890 initialize(participant); 891 } 892 ClassHierarchyWalker(Method* m) { 893 initialize_from_method(m); 894 initialize(NULL); 895 } 896 ClassHierarchyWalker(Klass* participant = NULL) { 897 _name = NULL; 898 _signature = NULL; 899 initialize(participant); 900 } 901 902 // This is common code for two searches: One for concrete subtypes, 903 // the other for concrete method implementations and overrides. 904 bool doing_subtype_search() { 905 return _name == NULL; 906 } 907 908 int num_participants() { return _num_participants; } 909 Klass* participant(int n) { 910 assert((uint)n <= (uint)_num_participants, "oob"); 911 return _participants[n]; 912 } 913 914 // Note: If n==num_participants, returns NULL. 915 Method* found_method(int n) { 916 assert((uint)n <= (uint)_num_participants, "oob"); 917 Method* fm = _found_methods[n]; 918 assert(n == _num_participants || fm != NULL, "proper usage"); 919 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity"); 920 return fm; 921 } 922 923 #ifdef ASSERT 924 // Assert that m is inherited into ctxk, without intervening overrides. 925 // (May return true even if this is not true, in corner cases where we punt.) 926 bool check_method_context(Klass* ctxk, Method* m) { 927 if (m->method_holder() == ctxk) 928 return true; // Quick win. 929 if (m->is_private()) 930 return false; // Quick lose. Should not happen. 931 if (!(m->is_public() || m->is_protected())) 932 // The override story is complex when packages get involved. 933 return true; // Must punt the assertion to true. 934 Klass* k = ctxk; 935 Method* lm = k->lookup_method(m->name(), m->signature()); 936 if (lm == NULL && k->oop_is_instance()) { 937 // It might be an interface method 938 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(), 939 m->signature()); 940 } 941 if (lm == m) 942 // Method m is inherited into ctxk. 943 return true; 944 if (lm != NULL) { 945 if (!(lm->is_public() || lm->is_protected())) { 946 // Method is [package-]private, so the override story is complex. 947 return true; // Must punt the assertion to true. 948 } 949 if (lm->is_static()) { 950 // Static methods don't override non-static so punt 951 return true; 952 } 953 if ( !Dependencies::is_concrete_method(lm) 954 && !Dependencies::is_concrete_method(m) 955 && lm->method_holder()->is_subtype_of(m->method_holder())) 956 // Method m is overridden by lm, but both are non-concrete. 957 return true; 958 } 959 ResourceMark rm; 960 tty->print_cr("Dependency method not found in the associated context:"); 961 tty->print_cr(" context = %s", ctxk->external_name()); 962 tty->print( " method = "); m->print_short_name(tty); tty->cr(); 963 if (lm != NULL) { 964 tty->print( " found = "); lm->print_short_name(tty); tty->cr(); 965 } 966 return false; 967 } 968 #endif 969 970 void add_participant(Klass* participant) { 971 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob"); 972 int np = _num_participants++; 973 _participants[np] = participant; 974 _participants[np+1] = NULL; 975 _found_methods[np+1] = NULL; 976 } 977 978 void record_witnesses(int add) { 979 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT; 980 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob"); 981 _record_witnesses = add; 982 } 983 984 bool is_witness(Klass* k) { 985 if (doing_subtype_search()) { 986 return Dependencies::is_concrete_klass(k); 987 } else { 988 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature); 989 if (m == NULL || !Dependencies::is_concrete_method(m)) return false; 990 _found_methods[_num_participants] = m; 991 // Note: If add_participant(k) is called, 992 // the method m will already be memoized for it. 993 return true; 994 } 995 } 996 997 bool is_participant(Klass* k) { 998 if (k == _participants[0]) { 999 return true; 1000 } else if (_num_participants <= 1) { 1001 return false; 1002 } else { 1003 return in_list(k, &_participants[1]); 1004 } 1005 } 1006 bool ignore_witness(Klass* witness) { 1007 if (_record_witnesses == 0) { 1008 return false; 1009 } else { 1010 --_record_witnesses; 1011 add_participant(witness); 1012 return true; 1013 } 1014 } 1015 static bool in_list(Klass* x, Klass** list) { 1016 for (int i = 0; ; i++) { 1017 Klass* y = list[i]; 1018 if (y == NULL) break; 1019 if (y == x) return true; 1020 } 1021 return false; // not in list 1022 } 1023 1024 private: 1025 // the actual search method: 1026 Klass* find_witness_anywhere(Klass* context_type, 1027 bool participants_hide_witnesses, 1028 bool top_level_call = true); 1029 // the spot-checking version: 1030 Klass* find_witness_in(KlassDepChange& changes, 1031 Klass* context_type, 1032 bool participants_hide_witnesses); 1033 public: 1034 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) { 1035 assert(doing_subtype_search(), "must set up a subtype search"); 1036 // When looking for unexpected concrete types, 1037 // do not look beneath expected ones. 1038 const bool participants_hide_witnesses = true; 1039 // CX > CC > C' is OK, even if C' is new. 1040 // CX > { CC, C' } is not OK if C' is new, and C' is the witness. 1041 if (changes != NULL) { 1042 return find_witness_in(*changes, context_type, participants_hide_witnesses); 1043 } else { 1044 return find_witness_anywhere(context_type, participants_hide_witnesses); 1045 } 1046 } 1047 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) { 1048 assert(!doing_subtype_search(), "must set up a method definer search"); 1049 // When looking for unexpected concrete methods, 1050 // look beneath expected ones, to see if there are overrides. 1051 const bool participants_hide_witnesses = true; 1052 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness. 1053 if (changes != NULL) { 1054 return find_witness_in(*changes, context_type, !participants_hide_witnesses); 1055 } else { 1056 return find_witness_anywhere(context_type, !participants_hide_witnesses); 1057 } 1058 } 1059 }; 1060 1061 #ifndef PRODUCT 1062 static int deps_find_witness_calls = 0; 1063 static int deps_find_witness_steps = 0; 1064 static int deps_find_witness_recursions = 0; 1065 static int deps_find_witness_singles = 0; 1066 static int deps_find_witness_print = 0; // set to -1 to force a final print 1067 static bool count_find_witness_calls() { 1068 if (TraceDependencies || LogCompilation) { 1069 int pcount = deps_find_witness_print + 1; 1070 bool final_stats = (pcount == 0); 1071 bool initial_call = (pcount == 1); 1072 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0); 1073 if (pcount < 0) pcount = 1; // crude overflow protection 1074 deps_find_witness_print = pcount; 1075 if (VerifyDependencies && initial_call) { 1076 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies"); 1077 } 1078 if (occasional_print || final_stats) { 1079 // Every now and then dump a little info about dependency searching. 1080 if (xtty != NULL) { 1081 ttyLocker ttyl; 1082 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'", 1083 deps_find_witness_calls, 1084 deps_find_witness_steps, 1085 deps_find_witness_recursions, 1086 deps_find_witness_singles); 1087 } 1088 if (final_stats || (TraceDependencies && WizardMode)) { 1089 ttyLocker ttyl; 1090 tty->print_cr("Dependency check (find_witness) " 1091 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d", 1092 deps_find_witness_calls, 1093 deps_find_witness_steps, 1094 (double)deps_find_witness_steps / deps_find_witness_calls, 1095 deps_find_witness_recursions, 1096 deps_find_witness_singles); 1097 } 1098 } 1099 return true; 1100 } 1101 return false; 1102 } 1103 #else 1104 #define count_find_witness_calls() (0) 1105 #endif //PRODUCT 1106 1107 1108 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes, 1109 Klass* context_type, 1110 bool participants_hide_witnesses) { 1111 assert(changes.involves_context(context_type), "irrelevant dependency"); 1112 Klass* new_type = changes.new_type(); 1113 1114 (void)count_find_witness_calls(); 1115 NOT_PRODUCT(deps_find_witness_singles++); 1116 1117 // Current thread must be in VM (not native mode, as in CI): 1118 assert(must_be_in_vm(), "raw oops here"); 1119 // Must not move the class hierarchy during this check: 1120 assert_locked_or_safepoint(Compile_lock); 1121 1122 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1123 if (nof_impls > 1) { 1124 // Avoid this case: *I.m > { A.m, C }; B.m > C 1125 // %%% Until this is fixed more systematically, bail out. 1126 // See corresponding comment in find_witness_anywhere. 1127 return context_type; 1128 } 1129 1130 assert(!is_participant(new_type), "only old classes are participants"); 1131 if (participants_hide_witnesses) { 1132 // If the new type is a subtype of a participant, we are done. 1133 for (int i = 0; i < num_participants(); i++) { 1134 Klass* part = participant(i); 1135 if (part == NULL) continue; 1136 assert(changes.involves_context(part) == new_type->is_subtype_of(part), 1137 "correct marking of participants, b/c new_type is unique"); 1138 if (changes.involves_context(part)) { 1139 // new guy is protected from this check by previous participant 1140 return NULL; 1141 } 1142 } 1143 } 1144 1145 if (is_witness(new_type) && 1146 !ignore_witness(new_type)) { 1147 return new_type; 1148 } 1149 1150 return NULL; 1151 } 1152 1153 1154 // Walk hierarchy under a context type, looking for unexpected types. 1155 // Do not report participant types, and recursively walk beneath 1156 // them only if participants_hide_witnesses is false. 1157 // If top_level_call is false, skip testing the context type, 1158 // because the caller has already considered it. 1159 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type, 1160 bool participants_hide_witnesses, 1161 bool top_level_call) { 1162 // Current thread must be in VM (not native mode, as in CI): 1163 assert(must_be_in_vm(), "raw oops here"); 1164 // Must not move the class hierarchy during this check: 1165 assert_locked_or_safepoint(Compile_lock); 1166 1167 bool do_counts = count_find_witness_calls(); 1168 1169 // Check the root of the sub-hierarchy first. 1170 if (top_level_call) { 1171 if (do_counts) { 1172 NOT_PRODUCT(deps_find_witness_calls++); 1173 NOT_PRODUCT(deps_find_witness_steps++); 1174 } 1175 if (is_participant(context_type)) { 1176 if (participants_hide_witnesses) return NULL; 1177 // else fall through to search loop... 1178 } else if (is_witness(context_type) && !ignore_witness(context_type)) { 1179 // The context is an abstract class or interface, to start with. 1180 return context_type; 1181 } 1182 } 1183 1184 // Now we must check each implementor and each subclass. 1185 // Use a short worklist to avoid blowing the stack. 1186 // Each worklist entry is a *chain* of subklass siblings to process. 1187 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit 1188 Klass* chains[CHAINMAX]; 1189 int chaini = 0; // index into worklist 1190 Klass* chain; // scratch variable 1191 #define ADD_SUBCLASS_CHAIN(k) { \ 1192 assert(chaini < CHAINMAX, "oob"); \ 1193 chain = InstanceKlass::cast(k)->subklass(); \ 1194 if (chain != NULL) chains[chaini++] = chain; } 1195 1196 // Look for non-abstract subclasses. 1197 // (Note: Interfaces do not have subclasses.) 1198 ADD_SUBCLASS_CHAIN(context_type); 1199 1200 // If it is an interface, search its direct implementors. 1201 // (Their subclasses are additional indirect implementors. 1202 // See InstanceKlass::add_implementor.) 1203 // (Note: nof_implementors is always zero for non-interfaces.) 1204 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1205 if (nof_impls > 1) { 1206 // Avoid this case: *I.m > { A.m, C }; B.m > C 1207 // Here, I.m has 2 concrete implementations, but m appears unique 1208 // as A.m, because the search misses B.m when checking C. 1209 // The inherited method B.m was getting missed by the walker 1210 // when interface 'I' was the starting point. 1211 // %%% Until this is fixed more systematically, bail out. 1212 // (Old CHA had the same limitation.) 1213 return context_type; 1214 } 1215 if (nof_impls > 0) { 1216 Klass* impl = InstanceKlass::cast(context_type)->implementor(); 1217 assert(impl != NULL, "just checking"); 1218 // If impl is the same as the context_type, then more than one 1219 // implementor has seen. No exact info in this case. 1220 if (impl == context_type) { 1221 return context_type; // report an inexact witness to this sad affair 1222 } 1223 if (do_counts) 1224 { NOT_PRODUCT(deps_find_witness_steps++); } 1225 if (is_participant(impl)) { 1226 if (!participants_hide_witnesses) { 1227 ADD_SUBCLASS_CHAIN(impl); 1228 } 1229 } else if (is_witness(impl) && !ignore_witness(impl)) { 1230 return impl; 1231 } else { 1232 ADD_SUBCLASS_CHAIN(impl); 1233 } 1234 } 1235 1236 // Recursively process each non-trivial sibling chain. 1237 while (chaini > 0) { 1238 Klass* chain = chains[--chaini]; 1239 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) { 1240 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); } 1241 if (is_participant(sub)) { 1242 if (participants_hide_witnesses) continue; 1243 // else fall through to process this guy's subclasses 1244 } else if (is_witness(sub) && !ignore_witness(sub)) { 1245 return sub; 1246 } 1247 if (chaini < (VerifyDependencies? 2: CHAINMAX)) { 1248 // Fast path. (Partially disabled if VerifyDependencies.) 1249 ADD_SUBCLASS_CHAIN(sub); 1250 } else { 1251 // Worklist overflow. Do a recursive call. Should be rare. 1252 // The recursive call will have its own worklist, of course. 1253 // (Note that sub has already been tested, so that there is 1254 // no need for the recursive call to re-test. That's handy, 1255 // since the recursive call sees sub as the context_type.) 1256 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); } 1257 Klass* witness = find_witness_anywhere(sub, 1258 participants_hide_witnesses, 1259 /*top_level_call=*/ false); 1260 if (witness != NULL) return witness; 1261 } 1262 } 1263 } 1264 1265 // No witness found. The dependency remains unbroken. 1266 return NULL; 1267 #undef ADD_SUBCLASS_CHAIN 1268 } 1269 1270 1271 bool Dependencies::is_concrete_klass(Klass* k) { 1272 if (k->is_abstract()) return false; 1273 // %%% We could treat classes which are concrete but 1274 // have not yet been instantiated as virtually abstract. 1275 // This would require a deoptimization barrier on first instantiation. 1276 //if (k->is_not_instantiated()) return false; 1277 return true; 1278 } 1279 1280 bool Dependencies::is_concrete_method(Method* m) { 1281 // Statics are irrelevant to virtual call sites. 1282 if (m->is_static()) return false; 1283 1284 // We could also return false if m does not yet appear to be 1285 // executed, if the VM version supports this distinction also. 1286 return !m->is_abstract() && 1287 !InstanceKlass::cast(m->method_holder())->is_interface(); 1288 // TODO: investigate whether default methods should be 1289 // considered as "concrete" in this situation. For now they 1290 // are not. 1291 } 1292 1293 1294 Klass* Dependencies::find_finalizable_subclass(Klass* k) { 1295 if (k->is_interface()) return NULL; 1296 if (k->has_finalizer()) return k; 1297 k = k->subklass(); 1298 while (k != NULL) { 1299 Klass* result = find_finalizable_subclass(k); 1300 if (result != NULL) return result; 1301 k = k->next_sibling(); 1302 } 1303 return NULL; 1304 } 1305 1306 1307 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) { 1308 if (k->is_abstract()) return false; 1309 // We could also return false if k does not yet appear to be 1310 // instantiated, if the VM version supports this distinction also. 1311 //if (k->is_not_instantiated()) return false; 1312 return true; 1313 } 1314 1315 bool Dependencies::is_concrete_method(ciMethod* m) { 1316 // Statics are irrelevant to virtual call sites. 1317 if (m->is_static()) return false; 1318 1319 // We could also return false if m does not yet appear to be 1320 // executed, if the VM version supports this distinction also. 1321 return !m->is_abstract(); 1322 } 1323 1324 1325 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) { 1326 return k->has_finalizable_subclass(); 1327 } 1328 1329 1330 // Any use of the contents (bytecodes) of a method must be 1331 // marked by an "evol_method" dependency, if those contents 1332 // can change. (Note: A method is always dependent on itself.) 1333 Klass* Dependencies::check_evol_method(Method* m) { 1334 assert(must_be_in_vm(), "raw oops here"); 1335 // Did somebody do a JVMTI RedefineClasses while our backs were turned? 1336 // Or is there a now a breakpoint? 1337 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.) 1338 if (m->is_old() 1339 || m->number_of_breakpoints() > 0) { 1340 return m->method_holder(); 1341 } else { 1342 return NULL; 1343 } 1344 } 1345 1346 // This is a strong assertion: It is that the given type 1347 // has no subtypes whatever. It is most useful for 1348 // optimizing checks on reflected types or on array types. 1349 // (Checks on types which are derived from real instances 1350 // can be optimized more strongly than this, because we 1351 // know that the checked type comes from a concrete type, 1352 // and therefore we can disregard abstract types.) 1353 Klass* Dependencies::check_leaf_type(Klass* ctxk) { 1354 assert(must_be_in_vm(), "raw oops here"); 1355 assert_locked_or_safepoint(Compile_lock); 1356 InstanceKlass* ctx = InstanceKlass::cast(ctxk); 1357 Klass* sub = ctx->subklass(); 1358 if (sub != NULL) { 1359 return sub; 1360 } else if (ctx->nof_implementors() != 0) { 1361 // if it is an interface, it must be unimplemented 1362 // (if it is not an interface, nof_implementors is always zero) 1363 Klass* impl = ctx->implementor(); 1364 assert(impl != NULL, "must be set"); 1365 return impl; 1366 } else { 1367 return NULL; 1368 } 1369 } 1370 1371 // Test the assertion that conck is the only concrete subtype* of ctxk. 1372 // The type conck itself is allowed to have have further concrete subtypes. 1373 // This allows the compiler to narrow occurrences of ctxk by conck, 1374 // when dealing with the types of actual instances. 1375 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk, 1376 Klass* conck, 1377 KlassDepChange* changes) { 1378 ClassHierarchyWalker wf(conck); 1379 return wf.find_witness_subtype(ctxk, changes); 1380 } 1381 1382 // If a non-concrete class has no concrete subtypes, it is not (yet) 1383 // instantiatable. This can allow the compiler to make some paths go 1384 // dead, if they are gated by a test of the type. 1385 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk, 1386 KlassDepChange* changes) { 1387 // Find any concrete subtype, with no participants: 1388 ClassHierarchyWalker wf; 1389 return wf.find_witness_subtype(ctxk, changes); 1390 } 1391 1392 1393 // If a concrete class has no concrete subtypes, it can always be 1394 // exactly typed. This allows the use of a cheaper type test. 1395 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk, 1396 KlassDepChange* changes) { 1397 // Find any concrete subtype, with only the ctxk as participant: 1398 ClassHierarchyWalker wf(ctxk); 1399 return wf.find_witness_subtype(ctxk, changes); 1400 } 1401 1402 1403 // Find the unique concrete proper subtype of ctxk, or NULL if there 1404 // is more than one concrete proper subtype. If there are no concrete 1405 // proper subtypes, return ctxk itself, whether it is concrete or not. 1406 // The returned subtype is allowed to have have further concrete subtypes. 1407 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }. 1408 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) { 1409 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking. 1410 wf.record_witnesses(1); // Record one other witness when walking. 1411 Klass* wit = wf.find_witness_subtype(ctxk); 1412 if (wit != NULL) return NULL; // Too many witnesses. 1413 Klass* conck = wf.participant(0); 1414 if (conck == NULL) { 1415 #ifndef PRODUCT 1416 // Make sure the dependency mechanism will pass this discovery: 1417 if (VerifyDependencies) { 1418 // Turn off dependency tracing while actually testing deps. 1419 FlagSetting fs(TraceDependencies, false); 1420 if (!Dependencies::is_concrete_klass(ctxk)) { 1421 guarantee(NULL == 1422 (void *)check_abstract_with_no_concrete_subtype(ctxk), 1423 "verify dep."); 1424 } else { 1425 guarantee(NULL == 1426 (void *)check_concrete_with_no_concrete_subtype(ctxk), 1427 "verify dep."); 1428 } 1429 } 1430 #endif //PRODUCT 1431 return ctxk; // Return ctxk as a flag for "no subtypes". 1432 } else { 1433 #ifndef PRODUCT 1434 // Make sure the dependency mechanism will pass this discovery: 1435 if (VerifyDependencies) { 1436 // Turn off dependency tracing while actually testing deps. 1437 FlagSetting fs(TraceDependencies, false); 1438 if (!Dependencies::is_concrete_klass(ctxk)) { 1439 guarantee(NULL == (void *) 1440 check_abstract_with_unique_concrete_subtype(ctxk, conck), 1441 "verify dep."); 1442 } 1443 } 1444 #endif //PRODUCT 1445 return conck; 1446 } 1447 } 1448 1449 // Test the assertion that the k[12] are the only concrete subtypes of ctxk, 1450 // except possibly for further subtypes of k[12] themselves. 1451 // The context type must be abstract. The types k1 and k2 are themselves 1452 // allowed to have further concrete subtypes. 1453 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes( 1454 Klass* ctxk, 1455 Klass* k1, 1456 Klass* k2, 1457 KlassDepChange* changes) { 1458 ClassHierarchyWalker wf; 1459 wf.add_participant(k1); 1460 wf.add_participant(k2); 1461 return wf.find_witness_subtype(ctxk, changes); 1462 } 1463 1464 // Search ctxk for concrete implementations. If there are klen or fewer, 1465 // pack them into the given array and return the number. 1466 // Otherwise, return -1, meaning the given array would overflow. 1467 // (Note that a return of 0 means there are exactly no concrete subtypes.) 1468 // In this search, if ctxk is concrete, it will be reported alone. 1469 // For any type CC reported, no proper subtypes of CC will be reported. 1470 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk, 1471 int klen, 1472 Klass* karray[]) { 1473 ClassHierarchyWalker wf; 1474 wf.record_witnesses(klen); 1475 Klass* wit = wf.find_witness_subtype(ctxk); 1476 if (wit != NULL) return -1; // Too many witnesses. 1477 int num = wf.num_participants(); 1478 assert(num <= klen, "oob"); 1479 // Pack the result array with the good news. 1480 for (int i = 0; i < num; i++) 1481 karray[i] = wf.participant(i); 1482 #ifndef PRODUCT 1483 // Make sure the dependency mechanism will pass this discovery: 1484 if (VerifyDependencies) { 1485 // Turn off dependency tracing while actually testing deps. 1486 FlagSetting fs(TraceDependencies, false); 1487 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) { 1488 case -1: // ctxk was itself concrete 1489 guarantee(num == 1 && karray[0] == ctxk, "verify dep."); 1490 break; 1491 case 0: 1492 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk), 1493 "verify dep."); 1494 break; 1495 case 1: 1496 guarantee(NULL == (void *) 1497 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]), 1498 "verify dep."); 1499 break; 1500 case 2: 1501 guarantee(NULL == (void *) 1502 check_abstract_with_exclusive_concrete_subtypes(ctxk, 1503 karray[0], 1504 karray[1]), 1505 "verify dep."); 1506 break; 1507 default: 1508 ShouldNotReachHere(); // klen > 2 yet supported 1509 } 1510 } 1511 #endif //PRODUCT 1512 return num; 1513 } 1514 1515 // If a class (or interface) has a unique concrete method uniqm, return NULL. 1516 // Otherwise, return a class that contains an interfering method. 1517 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm, 1518 KlassDepChange* changes) { 1519 // Here is a missing optimization: If uniqm->is_final(), 1520 // we don't really need to search beneath it for overrides. 1521 // This is probably not important, since we don't use dependencies 1522 // to track final methods. (They can't be "definalized".) 1523 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm); 1524 return wf.find_witness_definer(ctxk, changes); 1525 } 1526 1527 // Find the set of all non-abstract methods under ctxk that match m. 1528 // (The method m must be defined or inherited in ctxk.) 1529 // Include m itself in the set, unless it is abstract. 1530 // If this set has exactly one element, return that element. 1531 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) { 1532 ClassHierarchyWalker wf(m); 1533 assert(wf.check_method_context(ctxk, m), "proper context"); 1534 wf.record_witnesses(1); 1535 Klass* wit = wf.find_witness_definer(ctxk); 1536 if (wit != NULL) return NULL; // Too many witnesses. 1537 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0. 1538 if (Dependencies::is_concrete_method(m)) { 1539 if (fm == NULL) { 1540 // It turns out that m was always the only implementation. 1541 fm = m; 1542 } else if (fm != m) { 1543 // Two conflicting implementations after all. 1544 // (This can happen if m is inherited into ctxk and fm overrides it.) 1545 return NULL; 1546 } 1547 } 1548 #ifndef PRODUCT 1549 // Make sure the dependency mechanism will pass this discovery: 1550 if (VerifyDependencies && fm != NULL) { 1551 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm), 1552 "verify dep."); 1553 } 1554 #endif //PRODUCT 1555 return fm; 1556 } 1557 1558 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk, 1559 Method* m1, 1560 Method* m2, 1561 KlassDepChange* changes) { 1562 ClassHierarchyWalker wf(m1); 1563 wf.add_participant(m1->method_holder()); 1564 wf.add_participant(m2->method_holder()); 1565 return wf.find_witness_definer(ctxk, changes); 1566 } 1567 1568 // Find the set of all non-abstract methods under ctxk that match m[0]. 1569 // (The method m[0] must be defined or inherited in ctxk.) 1570 // Include m itself in the set, unless it is abstract. 1571 // Fill the given array m[0..(mlen-1)] with this set, and return the length. 1572 // (The length may be zero if no concrete methods are found anywhere.) 1573 // If there are too many concrete methods to fit in marray, return -1. 1574 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk, 1575 int mlen, 1576 Method* marray[]) { 1577 Method* m0 = marray[0]; 1578 ClassHierarchyWalker wf(m0); 1579 assert(wf.check_method_context(ctxk, m0), "proper context"); 1580 wf.record_witnesses(mlen); 1581 bool participants_hide_witnesses = true; 1582 Klass* wit = wf.find_witness_definer(ctxk); 1583 if (wit != NULL) return -1; // Too many witnesses. 1584 int num = wf.num_participants(); 1585 assert(num <= mlen, "oob"); 1586 // Keep track of whether m is also part of the result set. 1587 int mfill = 0; 1588 assert(marray[mfill] == m0, "sanity"); 1589 if (Dependencies::is_concrete_method(m0)) 1590 mfill++; // keep m0 as marray[0], the first result 1591 for (int i = 0; i < num; i++) { 1592 Method* fm = wf.found_method(i); 1593 if (fm == m0) continue; // Already put this guy in the list. 1594 if (mfill == mlen) { 1595 return -1; // Oops. Too many methods after all! 1596 } 1597 marray[mfill++] = fm; 1598 } 1599 #ifndef PRODUCT 1600 // Make sure the dependency mechanism will pass this discovery: 1601 if (VerifyDependencies) { 1602 // Turn off dependency tracing while actually testing deps. 1603 FlagSetting fs(TraceDependencies, false); 1604 switch (mfill) { 1605 case 1: 1606 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]), 1607 "verify dep."); 1608 break; 1609 case 2: 1610 guarantee(NULL == (void *) 1611 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]), 1612 "verify dep."); 1613 break; 1614 default: 1615 ShouldNotReachHere(); // mlen > 2 yet supported 1616 } 1617 } 1618 #endif //PRODUCT 1619 return mfill; 1620 } 1621 1622 1623 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) { 1624 Klass* search_at = ctxk; 1625 if (changes != NULL) 1626 search_at = changes->new_type(); // just look at the new bit 1627 return find_finalizable_subclass(search_at); 1628 } 1629 1630 1631 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) { 1632 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity"); 1633 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity"); 1634 if (changes == NULL) { 1635 // Validate all CallSites 1636 if (java_lang_invoke_CallSite::target(call_site) != method_handle) 1637 return call_site->klass(); // assertion failed 1638 } else { 1639 // Validate the given CallSite 1640 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) { 1641 assert(method_handle != changes->method_handle(), "must be"); 1642 return call_site->klass(); // assertion failed 1643 } 1644 } 1645 return NULL; // assertion still valid 1646 } 1647 1648 1649 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) { 1650 if (witness != NULL) { 1651 if (TraceDependencies) { 1652 print_dependency(witness, /*verbose=*/ true); 1653 } 1654 // The following is a no-op unless logging is enabled: 1655 log_dependency(witness); 1656 } 1657 } 1658 1659 1660 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) { 1661 assert_locked_or_safepoint(Compile_lock); 1662 Dependencies::check_valid_dependency_type(type()); 1663 1664 Klass* witness = NULL; 1665 switch (type()) { 1666 case evol_method: 1667 witness = check_evol_method(method_argument(0)); 1668 break; 1669 case leaf_type: 1670 witness = check_leaf_type(context_type()); 1671 break; 1672 case abstract_with_unique_concrete_subtype: 1673 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes); 1674 break; 1675 case abstract_with_no_concrete_subtype: 1676 witness = check_abstract_with_no_concrete_subtype(context_type(), changes); 1677 break; 1678 case concrete_with_no_concrete_subtype: 1679 witness = check_concrete_with_no_concrete_subtype(context_type(), changes); 1680 break; 1681 case unique_concrete_method: 1682 witness = check_unique_concrete_method(context_type(), method_argument(1), changes); 1683 break; 1684 case abstract_with_exclusive_concrete_subtypes_2: 1685 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes); 1686 break; 1687 case exclusive_concrete_methods_2: 1688 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes); 1689 break; 1690 case no_finalizable_subclasses: 1691 witness = check_has_no_finalizable_subclasses(context_type(), changes); 1692 break; 1693 default: 1694 witness = NULL; 1695 break; 1696 } 1697 trace_and_log_witness(witness); 1698 return witness; 1699 } 1700 1701 1702 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) { 1703 assert_locked_or_safepoint(Compile_lock); 1704 Dependencies::check_valid_dependency_type(type()); 1705 1706 Klass* witness = NULL; 1707 switch (type()) { 1708 case call_site_target_value: 1709 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes); 1710 break; 1711 default: 1712 witness = NULL; 1713 break; 1714 } 1715 trace_and_log_witness(witness); 1716 return witness; 1717 } 1718 1719 1720 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) { 1721 // Handle klass dependency 1722 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type())) 1723 return check_klass_dependency(changes.as_klass_change()); 1724 1725 // Handle CallSite dependency 1726 if (changes.is_call_site_change()) 1727 return check_call_site_dependency(changes.as_call_site_change()); 1728 1729 // irrelevant dependency; skip it 1730 return NULL; 1731 } 1732 1733 1734 void DepChange::print() { 1735 int nsup = 0, nint = 0; 1736 for (ContextStream str(*this); str.next(); ) { 1737 Klass* k = str.klass(); 1738 switch (str.change_type()) { 1739 case Change_new_type: 1740 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name()); 1741 break; 1742 case Change_new_sub: 1743 if (!WizardMode) { 1744 ++nsup; 1745 } else { 1746 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name()); 1747 } 1748 break; 1749 case Change_new_impl: 1750 if (!WizardMode) { 1751 ++nint; 1752 } else { 1753 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name()); 1754 } 1755 break; 1756 } 1757 } 1758 if (nsup + nint != 0) { 1759 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint); 1760 } 1761 } 1762 1763 void DepChange::ContextStream::start() { 1764 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL; 1765 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass); 1766 _klass = new_type; 1767 _ti_base = NULL; 1768 _ti_index = 0; 1769 _ti_limit = 0; 1770 } 1771 1772 bool DepChange::ContextStream::next() { 1773 switch (_change_type) { 1774 case Start_Klass: // initial state; _klass is the new type 1775 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces(); 1776 _ti_index = 0; 1777 _change_type = Change_new_type; 1778 return true; 1779 case Change_new_type: 1780 // fall through: 1781 _change_type = Change_new_sub; 1782 case Change_new_sub: 1783 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277 1784 { 1785 _klass = InstanceKlass::cast(_klass)->super(); 1786 if (_klass != NULL) { 1787 return true; 1788 } 1789 } 1790 // else set up _ti_limit and fall through: 1791 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length(); 1792 _change_type = Change_new_impl; 1793 case Change_new_impl: 1794 if (_ti_index < _ti_limit) { 1795 _klass = _ti_base->at(_ti_index++); 1796 return true; 1797 } 1798 // fall through: 1799 _change_type = NO_CHANGE; // iterator is exhausted 1800 case NO_CHANGE: 1801 break; 1802 default: 1803 ShouldNotReachHere(); 1804 } 1805 return false; 1806 } 1807 1808 void KlassDepChange::initialize() { 1809 // entire transaction must be under this lock: 1810 assert_lock_strong(Compile_lock); 1811 1812 // Mark all dependee and all its superclasses 1813 // Mark transitive interfaces 1814 for (ContextStream str(*this); str.next(); ) { 1815 Klass* d = str.klass(); 1816 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking"); 1817 InstanceKlass::cast(d)->set_is_marked_dependent(true); 1818 } 1819 } 1820 1821 KlassDepChange::~KlassDepChange() { 1822 // Unmark all dependee and all its superclasses 1823 // Unmark transitive interfaces 1824 for (ContextStream str(*this); str.next(); ) { 1825 Klass* d = str.klass(); 1826 InstanceKlass::cast(d)->set_is_marked_dependent(false); 1827 } 1828 } 1829 1830 bool KlassDepChange::involves_context(Klass* k) { 1831 if (k == NULL || !k->oop_is_instance()) { 1832 return false; 1833 } 1834 InstanceKlass* ik = InstanceKlass::cast(k); 1835 bool is_contained = ik->is_marked_dependent(); 1836 assert(is_contained == new_type()->is_subtype_of(k), 1837 "correct marking of potential context types"); 1838 return is_contained; 1839 } 1840 1841 #ifndef PRODUCT 1842 void Dependencies::print_statistics() { 1843 if (deps_find_witness_print != 0) { 1844 // Call one final time, to flush out the data. 1845 deps_find_witness_print = -1; 1846 count_find_witness_calls(); 1847 } 1848 } 1849 #endif