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 return o; 659 } 660 661 inline oop Dependencies::DepStream::recorded_oop_at(int i) { 662 return (_code != NULL) 663 ? _code->oop_at(i) 664 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i)); 665 } 666 667 Metadata* Dependencies::DepStream::argument(int i) { 668 Metadata* result = recorded_metadata_at(argument_index(i)); 669 670 if (result == NULL) { // Explicit context argument can be compressed 671 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 672 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) { 673 result = ctxk_encoded_as_null(type(), argument(ctxkj+1)); 674 } 675 } 676 677 assert(result == NULL || result->is_klass() || result->is_method(), "must be"); 678 return result; 679 } 680 681 /** 682 * Returns a unique identifier for each dependency argument. 683 */ 684 uintptr_t Dependencies::DepStream::get_identifier(int i) { 685 if (has_oop_argument()) { 686 return (uintptr_t)(oopDesc*)argument_oop(i); 687 } else { 688 return (uintptr_t)argument(i); 689 } 690 } 691 692 oop Dependencies::DepStream::argument_oop(int i) { 693 oop result = recorded_oop_at(argument_index(i)); 694 assert(result == NULL || result->is_oop(), "must be"); 695 return result; 696 } 697 698 Klass* Dependencies::DepStream::context_type() { 699 assert(must_be_in_vm(), "raw oops here"); 700 701 // Most dependencies have an explicit context type argument. 702 { 703 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 704 if (ctxkj >= 0) { 705 Metadata* k = argument(ctxkj); 706 assert(k != NULL && k->is_klass(), "type check"); 707 return (Klass*)k; 708 } 709 } 710 711 // Some dependencies are using the klass of the first object 712 // argument as implicit context type (e.g. call_site_target_value). 713 { 714 int ctxkj = dep_implicit_context_arg(type()); 715 if (ctxkj >= 0) { 716 Klass* k = argument_oop(ctxkj)->klass(); 717 assert(k != NULL && k->is_klass(), "type check"); 718 return (Klass*) k; 719 } 720 } 721 722 // And some dependencies don't have a context type at all, 723 // e.g. evol_method. 724 return NULL; 725 } 726 727 // ----------------- DependencySignature -------------------------------------- 728 bool DependencySignature::equals(const DependencySignature& sig) const { 729 if (type() != sig.type()) { 730 return false; 731 } 732 733 if (args_count() != sig.args_count()) { 734 return false; 735 } 736 737 for (int i = 0; i < sig.args_count(); i++) { 738 if (arg(i) != sig.arg(i)) { 739 return false; 740 } 741 } 742 return true; 743 } 744 745 746 // ----------------- DependencySignatureBuffer -------------------------------------- 747 DependencySignatureBuffer::DependencySignatureBuffer() { 748 _signatures = NEW_RESOURCE_ARRAY(GrowableArray<DependencySignature*>*, Dependencies::TYPE_LIMIT); 749 memset(_signatures, 0, sizeof(DependencySignature*) * Dependencies::TYPE_LIMIT); 750 } 751 752 /* Check if arguments are identical. Two dependency signatures are considered 753 * identical, if the type as well as all argument identifiers are identical. 754 * If the dependency has not already been checked, the dependency signature is 755 * added to the checked dependencies of the same type. The function returns 756 * false, which causes the dependency to be checked in the caller. 757 */ 758 bool DependencySignatureBuffer::add_if_missing(const DependencySignature& sig) { 759 const int index = sig.type(); 760 GrowableArray<DependencySignature*>* buffer = _signatures[index]; 761 if (buffer == NULL) { 762 buffer = new GrowableArray<DependencySignature*>(); 763 _signatures[index] = buffer; 764 } 765 766 // Check if we have already checked the dependency 767 for (int i = 0; i < buffer->length(); i++) { 768 DependencySignature* checked_signature = buffer->at(i); 769 if (checked_signature->equals(sig)) { 770 return true; 771 } 772 } 773 buffer->append((DependencySignature*)&sig); 774 return false; 775 } 776 777 778 /// Checking dependencies: 779 780 // This hierarchy walker inspects subtypes of a given type, 781 // trying to find a "bad" class which breaks a dependency. 782 // Such a class is called a "witness" to the broken dependency. 783 // While searching around, we ignore "participants", which 784 // are already known to the dependency. 785 class ClassHierarchyWalker { 786 public: 787 enum { PARTICIPANT_LIMIT = 3 }; 788 789 private: 790 // optional method descriptor to check for: 791 Symbol* _name; 792 Symbol* _signature; 793 794 // special classes which are not allowed to be witnesses: 795 Klass* _participants[PARTICIPANT_LIMIT+1]; 796 int _num_participants; 797 798 // cache of method lookups 799 Method* _found_methods[PARTICIPANT_LIMIT+1]; 800 801 // if non-zero, tells how many witnesses to convert to participants 802 int _record_witnesses; 803 804 void initialize(Klass* participant) { 805 _record_witnesses = 0; 806 _participants[0] = participant; 807 _found_methods[0] = NULL; 808 _num_participants = 0; 809 if (participant != NULL) { 810 // Terminating NULL. 811 _participants[1] = NULL; 812 _found_methods[1] = NULL; 813 _num_participants = 1; 814 } 815 } 816 817 void initialize_from_method(Method* m) { 818 assert(m != NULL && m->is_method(), "sanity"); 819 _name = m->name(); 820 _signature = m->signature(); 821 } 822 823 public: 824 // The walker is initialized to recognize certain methods and/or types 825 // as friendly participants. 826 ClassHierarchyWalker(Klass* participant, Method* m) { 827 initialize_from_method(m); 828 initialize(participant); 829 } 830 ClassHierarchyWalker(Method* m) { 831 initialize_from_method(m); 832 initialize(NULL); 833 } 834 ClassHierarchyWalker(Klass* participant = NULL) { 835 _name = NULL; 836 _signature = NULL; 837 initialize(participant); 838 } 839 840 // This is common code for two searches: One for concrete subtypes, 841 // the other for concrete method implementations and overrides. 842 bool doing_subtype_search() { 843 return _name == NULL; 844 } 845 846 int num_participants() { return _num_participants; } 847 Klass* participant(int n) { 848 assert((uint)n <= (uint)_num_participants, "oob"); 849 return _participants[n]; 850 } 851 852 // Note: If n==num_participants, returns NULL. 853 Method* found_method(int n) { 854 assert((uint)n <= (uint)_num_participants, "oob"); 855 Method* fm = _found_methods[n]; 856 assert(n == _num_participants || fm != NULL, "proper usage"); 857 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity"); 858 return fm; 859 } 860 861 #ifdef ASSERT 862 // Assert that m is inherited into ctxk, without intervening overrides. 863 // (May return true even if this is not true, in corner cases where we punt.) 864 bool check_method_context(Klass* ctxk, Method* m) { 865 if (m->method_holder() == ctxk) 866 return true; // Quick win. 867 if (m->is_private()) 868 return false; // Quick lose. Should not happen. 869 if (!(m->is_public() || m->is_protected())) 870 // The override story is complex when packages get involved. 871 return true; // Must punt the assertion to true. 872 Klass* k = ctxk; 873 Method* lm = k->lookup_method(m->name(), m->signature()); 874 if (lm == NULL && k->oop_is_instance()) { 875 // It might be an interface method 876 lm = ((InstanceKlass*)k)->lookup_method_in_ordered_interfaces(m->name(), 877 m->signature()); 878 } 879 if (lm == m) 880 // Method m is inherited into ctxk. 881 return true; 882 if (lm != NULL) { 883 if (!(lm->is_public() || lm->is_protected())) { 884 // Method is [package-]private, so the override story is complex. 885 return true; // Must punt the assertion to true. 886 } 887 if (lm->is_static()) { 888 // Static methods don't override non-static so punt 889 return true; 890 } 891 if ( !Dependencies::is_concrete_method(lm) 892 && !Dependencies::is_concrete_method(m) 893 && lm->method_holder()->is_subtype_of(m->method_holder())) 894 // Method m is overridden by lm, but both are non-concrete. 895 return true; 896 } 897 ResourceMark rm; 898 tty->print_cr("Dependency method not found in the associated context:"); 899 tty->print_cr(" context = %s", ctxk->external_name()); 900 tty->print( " method = "); m->print_short_name(tty); tty->cr(); 901 if (lm != NULL) { 902 tty->print( " found = "); lm->print_short_name(tty); tty->cr(); 903 } 904 return false; 905 } 906 #endif 907 908 void add_participant(Klass* participant) { 909 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob"); 910 int np = _num_participants++; 911 _participants[np] = participant; 912 _participants[np+1] = NULL; 913 _found_methods[np+1] = NULL; 914 } 915 916 void record_witnesses(int add) { 917 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT; 918 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob"); 919 _record_witnesses = add; 920 } 921 922 bool is_witness(Klass* k) { 923 if (doing_subtype_search()) { 924 return Dependencies::is_concrete_klass(k); 925 } else { 926 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature); 927 if (m == NULL || !Dependencies::is_concrete_method(m)) return false; 928 _found_methods[_num_participants] = m; 929 // Note: If add_participant(k) is called, 930 // the method m will already be memoized for it. 931 return true; 932 } 933 } 934 935 bool is_participant(Klass* k) { 936 if (k == _participants[0]) { 937 return true; 938 } else if (_num_participants <= 1) { 939 return false; 940 } else { 941 return in_list(k, &_participants[1]); 942 } 943 } 944 bool ignore_witness(Klass* witness) { 945 if (_record_witnesses == 0) { 946 return false; 947 } else { 948 --_record_witnesses; 949 add_participant(witness); 950 return true; 951 } 952 } 953 static bool in_list(Klass* x, Klass** list) { 954 for (int i = 0; ; i++) { 955 Klass* y = list[i]; 956 if (y == NULL) break; 957 if (y == x) return true; 958 } 959 return false; // not in list 960 } 961 962 private: 963 // the actual search method: 964 Klass* find_witness_anywhere(Klass* context_type, 965 bool participants_hide_witnesses, 966 bool top_level_call = true); 967 // the spot-checking version: 968 Klass* find_witness_in(KlassDepChange& changes, 969 Klass* context_type, 970 bool participants_hide_witnesses); 971 public: 972 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) { 973 assert(doing_subtype_search(), "must set up a subtype search"); 974 // When looking for unexpected concrete types, 975 // do not look beneath expected ones. 976 const bool participants_hide_witnesses = true; 977 // CX > CC > C' is OK, even if C' is new. 978 // CX > { CC, C' } is not OK if C' is new, and C' is the witness. 979 if (changes != NULL) { 980 return find_witness_in(*changes, context_type, participants_hide_witnesses); 981 } else { 982 return find_witness_anywhere(context_type, participants_hide_witnesses); 983 } 984 } 985 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) { 986 assert(!doing_subtype_search(), "must set up a method definer search"); 987 // When looking for unexpected concrete methods, 988 // look beneath expected ones, to see if there are overrides. 989 const bool participants_hide_witnesses = true; 990 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness. 991 if (changes != NULL) { 992 return find_witness_in(*changes, context_type, !participants_hide_witnesses); 993 } else { 994 return find_witness_anywhere(context_type, !participants_hide_witnesses); 995 } 996 } 997 }; 998 999 #ifndef PRODUCT 1000 static int deps_find_witness_calls = 0; 1001 static int deps_find_witness_steps = 0; 1002 static int deps_find_witness_recursions = 0; 1003 static int deps_find_witness_singles = 0; 1004 static int deps_find_witness_print = 0; // set to -1 to force a final print 1005 static bool count_find_witness_calls() { 1006 if (TraceDependencies || LogCompilation) { 1007 int pcount = deps_find_witness_print + 1; 1008 bool final_stats = (pcount == 0); 1009 bool initial_call = (pcount == 1); 1010 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0); 1011 if (pcount < 0) pcount = 1; // crude overflow protection 1012 deps_find_witness_print = pcount; 1013 if (VerifyDependencies && initial_call) { 1014 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies"); 1015 } 1016 if (occasional_print || final_stats) { 1017 // Every now and then dump a little info about dependency searching. 1018 if (xtty != NULL) { 1019 ttyLocker ttyl; 1020 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'", 1021 deps_find_witness_calls, 1022 deps_find_witness_steps, 1023 deps_find_witness_recursions, 1024 deps_find_witness_singles); 1025 } 1026 if (final_stats || (TraceDependencies && WizardMode)) { 1027 ttyLocker ttyl; 1028 tty->print_cr("Dependency check (find_witness) " 1029 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d", 1030 deps_find_witness_calls, 1031 deps_find_witness_steps, 1032 (double)deps_find_witness_steps / deps_find_witness_calls, 1033 deps_find_witness_recursions, 1034 deps_find_witness_singles); 1035 } 1036 } 1037 return true; 1038 } 1039 return false; 1040 } 1041 #else 1042 #define count_find_witness_calls() (0) 1043 #endif //PRODUCT 1044 1045 1046 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes, 1047 Klass* context_type, 1048 bool participants_hide_witnesses) { 1049 assert(changes.involves_context(context_type), "irrelevant dependency"); 1050 Klass* new_type = changes.new_type(); 1051 1052 (void)count_find_witness_calls(); 1053 NOT_PRODUCT(deps_find_witness_singles++); 1054 1055 // Current thread must be in VM (not native mode, as in CI): 1056 assert(must_be_in_vm(), "raw oops here"); 1057 // Must not move the class hierarchy during this check: 1058 assert_locked_or_safepoint(Compile_lock); 1059 1060 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1061 if (nof_impls > 1) { 1062 // Avoid this case: *I.m > { A.m, C }; B.m > C 1063 // %%% Until this is fixed more systematically, bail out. 1064 // See corresponding comment in find_witness_anywhere. 1065 return context_type; 1066 } 1067 1068 assert(!is_participant(new_type), "only old classes are participants"); 1069 if (participants_hide_witnesses) { 1070 // If the new type is a subtype of a participant, we are done. 1071 for (int i = 0; i < num_participants(); i++) { 1072 Klass* part = participant(i); 1073 if (part == NULL) continue; 1074 assert(changes.involves_context(part) == new_type->is_subtype_of(part), 1075 "correct marking of participants, b/c new_type is unique"); 1076 if (changes.involves_context(part)) { 1077 // new guy is protected from this check by previous participant 1078 return NULL; 1079 } 1080 } 1081 } 1082 1083 if (is_witness(new_type) && 1084 !ignore_witness(new_type)) { 1085 return new_type; 1086 } 1087 1088 return NULL; 1089 } 1090 1091 1092 // Walk hierarchy under a context type, looking for unexpected types. 1093 // Do not report participant types, and recursively walk beneath 1094 // them only if participants_hide_witnesses is false. 1095 // If top_level_call is false, skip testing the context type, 1096 // because the caller has already considered it. 1097 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type, 1098 bool participants_hide_witnesses, 1099 bool top_level_call) { 1100 // Current thread must be in VM (not native mode, as in CI): 1101 assert(must_be_in_vm(), "raw oops here"); 1102 // Must not move the class hierarchy during this check: 1103 assert_locked_or_safepoint(Compile_lock); 1104 1105 bool do_counts = count_find_witness_calls(); 1106 1107 // Check the root of the sub-hierarchy first. 1108 if (top_level_call) { 1109 if (do_counts) { 1110 NOT_PRODUCT(deps_find_witness_calls++); 1111 NOT_PRODUCT(deps_find_witness_steps++); 1112 } 1113 if (is_participant(context_type)) { 1114 if (participants_hide_witnesses) return NULL; 1115 // else fall through to search loop... 1116 } else if (is_witness(context_type) && !ignore_witness(context_type)) { 1117 // The context is an abstract class or interface, to start with. 1118 return context_type; 1119 } 1120 } 1121 1122 // Now we must check each implementor and each subclass. 1123 // Use a short worklist to avoid blowing the stack. 1124 // Each worklist entry is a *chain* of subklass siblings to process. 1125 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit 1126 Klass* chains[CHAINMAX]; 1127 int chaini = 0; // index into worklist 1128 Klass* chain; // scratch variable 1129 #define ADD_SUBCLASS_CHAIN(k) { \ 1130 assert(chaini < CHAINMAX, "oob"); \ 1131 chain = InstanceKlass::cast(k)->subklass(); \ 1132 if (chain != NULL) chains[chaini++] = chain; } 1133 1134 // Look for non-abstract subclasses. 1135 // (Note: Interfaces do not have subclasses.) 1136 ADD_SUBCLASS_CHAIN(context_type); 1137 1138 // If it is an interface, search its direct implementors. 1139 // (Their subclasses are additional indirect implementors. 1140 // See InstanceKlass::add_implementor.) 1141 // (Note: nof_implementors is always zero for non-interfaces.) 1142 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1143 if (nof_impls > 1) { 1144 // Avoid this case: *I.m > { A.m, C }; B.m > C 1145 // Here, I.m has 2 concrete implementations, but m appears unique 1146 // as A.m, because the search misses B.m when checking C. 1147 // The inherited method B.m was getting missed by the walker 1148 // when interface 'I' was the starting point. 1149 // %%% Until this is fixed more systematically, bail out. 1150 // (Old CHA had the same limitation.) 1151 return context_type; 1152 } 1153 if (nof_impls > 0) { 1154 Klass* impl = InstanceKlass::cast(context_type)->implementor(); 1155 assert(impl != NULL, "just checking"); 1156 // If impl is the same as the context_type, then more than one 1157 // implementor has seen. No exact info in this case. 1158 if (impl == context_type) { 1159 return context_type; // report an inexact witness to this sad affair 1160 } 1161 if (do_counts) 1162 { NOT_PRODUCT(deps_find_witness_steps++); } 1163 if (is_participant(impl)) { 1164 if (!participants_hide_witnesses) { 1165 ADD_SUBCLASS_CHAIN(impl); 1166 } 1167 } else if (is_witness(impl) && !ignore_witness(impl)) { 1168 return impl; 1169 } else { 1170 ADD_SUBCLASS_CHAIN(impl); 1171 } 1172 } 1173 1174 // Recursively process each non-trivial sibling chain. 1175 while (chaini > 0) { 1176 Klass* chain = chains[--chaini]; 1177 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) { 1178 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); } 1179 if (is_participant(sub)) { 1180 if (participants_hide_witnesses) continue; 1181 // else fall through to process this guy's subclasses 1182 } else if (is_witness(sub) && !ignore_witness(sub)) { 1183 return sub; 1184 } 1185 if (chaini < (VerifyDependencies? 2: CHAINMAX)) { 1186 // Fast path. (Partially disabled if VerifyDependencies.) 1187 ADD_SUBCLASS_CHAIN(sub); 1188 } else { 1189 // Worklist overflow. Do a recursive call. Should be rare. 1190 // The recursive call will have its own worklist, of course. 1191 // (Note that sub has already been tested, so that there is 1192 // no need for the recursive call to re-test. That's handy, 1193 // since the recursive call sees sub as the context_type.) 1194 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); } 1195 Klass* witness = find_witness_anywhere(sub, 1196 participants_hide_witnesses, 1197 /*top_level_call=*/ false); 1198 if (witness != NULL) return witness; 1199 } 1200 } 1201 } 1202 1203 // No witness found. The dependency remains unbroken. 1204 return NULL; 1205 #undef ADD_SUBCLASS_CHAIN 1206 } 1207 1208 1209 bool Dependencies::is_concrete_klass(Klass* k) { 1210 if (k->is_abstract()) return false; 1211 // %%% We could treat classes which are concrete but 1212 // have not yet been instantiated as virtually abstract. 1213 // This would require a deoptimization barrier on first instantiation. 1214 //if (k->is_not_instantiated()) return false; 1215 return true; 1216 } 1217 1218 bool Dependencies::is_concrete_method(Method* m) { 1219 // Statics are irrelevant to virtual call sites. 1220 if (m->is_static()) return false; 1221 1222 // We could also return false if m does not yet appear to be 1223 // executed, if the VM version supports this distinction also. 1224 // Default methods are considered "concrete" as well. 1225 return !m->is_abstract() && 1226 !m->is_overpass(); // error functions aren't concrete 1227 } 1228 1229 1230 Klass* Dependencies::find_finalizable_subclass(Klass* k) { 1231 if (k->is_interface()) return NULL; 1232 if (k->has_finalizer()) return k; 1233 k = k->subklass(); 1234 while (k != NULL) { 1235 Klass* result = find_finalizable_subclass(k); 1236 if (result != NULL) return result; 1237 k = k->next_sibling(); 1238 } 1239 return NULL; 1240 } 1241 1242 1243 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) { 1244 if (k->is_abstract()) return false; 1245 // We could also return false if k does not yet appear to be 1246 // instantiated, if the VM version supports this distinction also. 1247 //if (k->is_not_instantiated()) return false; 1248 return true; 1249 } 1250 1251 bool Dependencies::is_concrete_method(ciMethod* m) { 1252 // Statics are irrelevant to virtual call sites. 1253 if (m->is_static()) return false; 1254 1255 // We could also return false if m does not yet appear to be 1256 // executed, if the VM version supports this distinction also. 1257 return !m->is_abstract(); 1258 } 1259 1260 1261 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) { 1262 return k->has_finalizable_subclass(); 1263 } 1264 1265 1266 // Any use of the contents (bytecodes) of a method must be 1267 // marked by an "evol_method" dependency, if those contents 1268 // can change. (Note: A method is always dependent on itself.) 1269 Klass* Dependencies::check_evol_method(Method* m) { 1270 assert(must_be_in_vm(), "raw oops here"); 1271 // Did somebody do a JVMTI RedefineClasses while our backs were turned? 1272 // Or is there a now a breakpoint? 1273 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.) 1274 if (m->is_old() 1275 || m->number_of_breakpoints() > 0) { 1276 return m->method_holder(); 1277 } else { 1278 return NULL; 1279 } 1280 } 1281 1282 // This is a strong assertion: It is that the given type 1283 // has no subtypes whatever. It is most useful for 1284 // optimizing checks on reflected types or on array types. 1285 // (Checks on types which are derived from real instances 1286 // can be optimized more strongly than this, because we 1287 // know that the checked type comes from a concrete type, 1288 // and therefore we can disregard abstract types.) 1289 Klass* Dependencies::check_leaf_type(Klass* ctxk) { 1290 assert(must_be_in_vm(), "raw oops here"); 1291 assert_locked_or_safepoint(Compile_lock); 1292 InstanceKlass* ctx = InstanceKlass::cast(ctxk); 1293 Klass* sub = ctx->subklass(); 1294 if (sub != NULL) { 1295 return sub; 1296 } else if (ctx->nof_implementors() != 0) { 1297 // if it is an interface, it must be unimplemented 1298 // (if it is not an interface, nof_implementors is always zero) 1299 Klass* impl = ctx->implementor(); 1300 assert(impl != NULL, "must be set"); 1301 return impl; 1302 } else { 1303 return NULL; 1304 } 1305 } 1306 1307 // Test the assertion that conck is the only concrete subtype* of ctxk. 1308 // The type conck itself is allowed to have have further concrete subtypes. 1309 // This allows the compiler to narrow occurrences of ctxk by conck, 1310 // when dealing with the types of actual instances. 1311 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk, 1312 Klass* conck, 1313 KlassDepChange* changes) { 1314 ClassHierarchyWalker wf(conck); 1315 return wf.find_witness_subtype(ctxk, changes); 1316 } 1317 1318 // If a non-concrete class has no concrete subtypes, it is not (yet) 1319 // instantiatable. This can allow the compiler to make some paths go 1320 // dead, if they are gated by a test of the type. 1321 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk, 1322 KlassDepChange* changes) { 1323 // Find any concrete subtype, with no participants: 1324 ClassHierarchyWalker wf; 1325 return wf.find_witness_subtype(ctxk, changes); 1326 } 1327 1328 1329 // If a concrete class has no concrete subtypes, it can always be 1330 // exactly typed. This allows the use of a cheaper type test. 1331 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk, 1332 KlassDepChange* changes) { 1333 // Find any concrete subtype, with only the ctxk as participant: 1334 ClassHierarchyWalker wf(ctxk); 1335 return wf.find_witness_subtype(ctxk, changes); 1336 } 1337 1338 1339 // Find the unique concrete proper subtype of ctxk, or NULL if there 1340 // is more than one concrete proper subtype. If there are no concrete 1341 // proper subtypes, return ctxk itself, whether it is concrete or not. 1342 // The returned subtype is allowed to have have further concrete subtypes. 1343 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }. 1344 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) { 1345 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking. 1346 wf.record_witnesses(1); // Record one other witness when walking. 1347 Klass* wit = wf.find_witness_subtype(ctxk); 1348 if (wit != NULL) return NULL; // Too many witnesses. 1349 Klass* conck = wf.participant(0); 1350 if (conck == NULL) { 1351 #ifndef PRODUCT 1352 // Make sure the dependency mechanism will pass this discovery: 1353 if (VerifyDependencies) { 1354 // Turn off dependency tracing while actually testing deps. 1355 FlagSetting fs(TraceDependencies, false); 1356 if (!Dependencies::is_concrete_klass(ctxk)) { 1357 guarantee(NULL == 1358 (void *)check_abstract_with_no_concrete_subtype(ctxk), 1359 "verify dep."); 1360 } else { 1361 guarantee(NULL == 1362 (void *)check_concrete_with_no_concrete_subtype(ctxk), 1363 "verify dep."); 1364 } 1365 } 1366 #endif //PRODUCT 1367 return ctxk; // Return ctxk as a flag for "no subtypes". 1368 } else { 1369 #ifndef PRODUCT 1370 // Make sure the dependency mechanism will pass this discovery: 1371 if (VerifyDependencies) { 1372 // Turn off dependency tracing while actually testing deps. 1373 FlagSetting fs(TraceDependencies, false); 1374 if (!Dependencies::is_concrete_klass(ctxk)) { 1375 guarantee(NULL == (void *) 1376 check_abstract_with_unique_concrete_subtype(ctxk, conck), 1377 "verify dep."); 1378 } 1379 } 1380 #endif //PRODUCT 1381 return conck; 1382 } 1383 } 1384 1385 // Test the assertion that the k[12] are the only concrete subtypes of ctxk, 1386 // except possibly for further subtypes of k[12] themselves. 1387 // The context type must be abstract. The types k1 and k2 are themselves 1388 // allowed to have further concrete subtypes. 1389 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes( 1390 Klass* ctxk, 1391 Klass* k1, 1392 Klass* k2, 1393 KlassDepChange* changes) { 1394 ClassHierarchyWalker wf; 1395 wf.add_participant(k1); 1396 wf.add_participant(k2); 1397 return wf.find_witness_subtype(ctxk, changes); 1398 } 1399 1400 // Search ctxk for concrete implementations. If there are klen or fewer, 1401 // pack them into the given array and return the number. 1402 // Otherwise, return -1, meaning the given array would overflow. 1403 // (Note that a return of 0 means there are exactly no concrete subtypes.) 1404 // In this search, if ctxk is concrete, it will be reported alone. 1405 // For any type CC reported, no proper subtypes of CC will be reported. 1406 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk, 1407 int klen, 1408 Klass* karray[]) { 1409 ClassHierarchyWalker wf; 1410 wf.record_witnesses(klen); 1411 Klass* wit = wf.find_witness_subtype(ctxk); 1412 if (wit != NULL) return -1; // Too many witnesses. 1413 int num = wf.num_participants(); 1414 assert(num <= klen, "oob"); 1415 // Pack the result array with the good news. 1416 for (int i = 0; i < num; i++) 1417 karray[i] = wf.participant(i); 1418 #ifndef PRODUCT 1419 // Make sure the dependency mechanism will pass this discovery: 1420 if (VerifyDependencies) { 1421 // Turn off dependency tracing while actually testing deps. 1422 FlagSetting fs(TraceDependencies, false); 1423 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) { 1424 case -1: // ctxk was itself concrete 1425 guarantee(num == 1 && karray[0] == ctxk, "verify dep."); 1426 break; 1427 case 0: 1428 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk), 1429 "verify dep."); 1430 break; 1431 case 1: 1432 guarantee(NULL == (void *) 1433 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]), 1434 "verify dep."); 1435 break; 1436 case 2: 1437 guarantee(NULL == (void *) 1438 check_abstract_with_exclusive_concrete_subtypes(ctxk, 1439 karray[0], 1440 karray[1]), 1441 "verify dep."); 1442 break; 1443 default: 1444 ShouldNotReachHere(); // klen > 2 yet supported 1445 } 1446 } 1447 #endif //PRODUCT 1448 return num; 1449 } 1450 1451 // If a class (or interface) has a unique concrete method uniqm, return NULL. 1452 // Otherwise, return a class that contains an interfering method. 1453 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm, 1454 KlassDepChange* changes) { 1455 // Here is a missing optimization: If uniqm->is_final(), 1456 // we don't really need to search beneath it for overrides. 1457 // This is probably not important, since we don't use dependencies 1458 // to track final methods. (They can't be "definalized".) 1459 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm); 1460 return wf.find_witness_definer(ctxk, changes); 1461 } 1462 1463 // Find the set of all non-abstract methods under ctxk that match m. 1464 // (The method m must be defined or inherited in ctxk.) 1465 // Include m itself in the set, unless it is abstract. 1466 // If this set has exactly one element, return that element. 1467 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) { 1468 ClassHierarchyWalker wf(m); 1469 assert(wf.check_method_context(ctxk, m), "proper context"); 1470 wf.record_witnesses(1); 1471 Klass* wit = wf.find_witness_definer(ctxk); 1472 if (wit != NULL) return NULL; // Too many witnesses. 1473 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0. 1474 if (Dependencies::is_concrete_method(m)) { 1475 if (fm == NULL) { 1476 // It turns out that m was always the only implementation. 1477 fm = m; 1478 } else if (fm != m) { 1479 // Two conflicting implementations after all. 1480 // (This can happen if m is inherited into ctxk and fm overrides it.) 1481 return NULL; 1482 } 1483 } 1484 #ifndef PRODUCT 1485 // Make sure the dependency mechanism will pass this discovery: 1486 if (VerifyDependencies && fm != NULL) { 1487 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm), 1488 "verify dep."); 1489 } 1490 #endif //PRODUCT 1491 return fm; 1492 } 1493 1494 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk, 1495 Method* m1, 1496 Method* m2, 1497 KlassDepChange* changes) { 1498 ClassHierarchyWalker wf(m1); 1499 wf.add_participant(m1->method_holder()); 1500 wf.add_participant(m2->method_holder()); 1501 return wf.find_witness_definer(ctxk, changes); 1502 } 1503 1504 // Find the set of all non-abstract methods under ctxk that match m[0]. 1505 // (The method m[0] must be defined or inherited in ctxk.) 1506 // Include m itself in the set, unless it is abstract. 1507 // Fill the given array m[0..(mlen-1)] with this set, and return the length. 1508 // (The length may be zero if no concrete methods are found anywhere.) 1509 // If there are too many concrete methods to fit in marray, return -1. 1510 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk, 1511 int mlen, 1512 Method* marray[]) { 1513 Method* m0 = marray[0]; 1514 ClassHierarchyWalker wf(m0); 1515 assert(wf.check_method_context(ctxk, m0), "proper context"); 1516 wf.record_witnesses(mlen); 1517 bool participants_hide_witnesses = true; 1518 Klass* wit = wf.find_witness_definer(ctxk); 1519 if (wit != NULL) return -1; // Too many witnesses. 1520 int num = wf.num_participants(); 1521 assert(num <= mlen, "oob"); 1522 // Keep track of whether m is also part of the result set. 1523 int mfill = 0; 1524 assert(marray[mfill] == m0, "sanity"); 1525 if (Dependencies::is_concrete_method(m0)) 1526 mfill++; // keep m0 as marray[0], the first result 1527 for (int i = 0; i < num; i++) { 1528 Method* fm = wf.found_method(i); 1529 if (fm == m0) continue; // Already put this guy in the list. 1530 if (mfill == mlen) { 1531 return -1; // Oops. Too many methods after all! 1532 } 1533 marray[mfill++] = fm; 1534 } 1535 #ifndef PRODUCT 1536 // Make sure the dependency mechanism will pass this discovery: 1537 if (VerifyDependencies) { 1538 // Turn off dependency tracing while actually testing deps. 1539 FlagSetting fs(TraceDependencies, false); 1540 switch (mfill) { 1541 case 1: 1542 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]), 1543 "verify dep."); 1544 break; 1545 case 2: 1546 guarantee(NULL == (void *) 1547 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]), 1548 "verify dep."); 1549 break; 1550 default: 1551 ShouldNotReachHere(); // mlen > 2 yet supported 1552 } 1553 } 1554 #endif //PRODUCT 1555 return mfill; 1556 } 1557 1558 1559 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) { 1560 Klass* search_at = ctxk; 1561 if (changes != NULL) 1562 search_at = changes->new_type(); // just look at the new bit 1563 return find_finalizable_subclass(search_at); 1564 } 1565 1566 1567 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) { 1568 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity"); 1569 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity"); 1570 if (changes == NULL) { 1571 // Validate all CallSites 1572 if (java_lang_invoke_CallSite::target(call_site) != method_handle) 1573 return call_site->klass(); // assertion failed 1574 } else { 1575 // Validate the given CallSite 1576 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) { 1577 assert(method_handle != changes->method_handle(), "must be"); 1578 return call_site->klass(); // assertion failed 1579 } 1580 } 1581 return NULL; // assertion still valid 1582 } 1583 1584 1585 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) { 1586 if (witness != NULL) { 1587 if (TraceDependencies) { 1588 print_dependency(witness, /*verbose=*/ true); 1589 } 1590 // The following is a no-op unless logging is enabled: 1591 log_dependency(witness); 1592 } 1593 } 1594 1595 1596 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) { 1597 assert_locked_or_safepoint(Compile_lock); 1598 Dependencies::check_valid_dependency_type(type()); 1599 1600 Klass* witness = NULL; 1601 switch (type()) { 1602 case evol_method: 1603 witness = check_evol_method(method_argument(0)); 1604 break; 1605 case leaf_type: 1606 witness = check_leaf_type(context_type()); 1607 break; 1608 case abstract_with_unique_concrete_subtype: 1609 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes); 1610 break; 1611 case abstract_with_no_concrete_subtype: 1612 witness = check_abstract_with_no_concrete_subtype(context_type(), changes); 1613 break; 1614 case concrete_with_no_concrete_subtype: 1615 witness = check_concrete_with_no_concrete_subtype(context_type(), changes); 1616 break; 1617 case unique_concrete_method: 1618 witness = check_unique_concrete_method(context_type(), method_argument(1), changes); 1619 break; 1620 case abstract_with_exclusive_concrete_subtypes_2: 1621 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes); 1622 break; 1623 case exclusive_concrete_methods_2: 1624 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes); 1625 break; 1626 case no_finalizable_subclasses: 1627 witness = check_has_no_finalizable_subclasses(context_type(), changes); 1628 break; 1629 default: 1630 witness = NULL; 1631 break; 1632 } 1633 trace_and_log_witness(witness); 1634 return witness; 1635 } 1636 1637 1638 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) { 1639 assert_locked_or_safepoint(Compile_lock); 1640 Dependencies::check_valid_dependency_type(type()); 1641 1642 Klass* witness = NULL; 1643 switch (type()) { 1644 case call_site_target_value: 1645 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes); 1646 break; 1647 default: 1648 witness = NULL; 1649 break; 1650 } 1651 trace_and_log_witness(witness); 1652 return witness; 1653 } 1654 1655 1656 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) { 1657 // Handle klass dependency 1658 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type())) 1659 return check_klass_dependency(changes.as_klass_change()); 1660 1661 // Handle CallSite dependency 1662 if (changes.is_call_site_change()) 1663 return check_call_site_dependency(changes.as_call_site_change()); 1664 1665 // irrelevant dependency; skip it 1666 return NULL; 1667 } 1668 1669 1670 void DepChange::print() { 1671 int nsup = 0, nint = 0; 1672 for (ContextStream str(*this); str.next(); ) { 1673 Klass* k = str.klass(); 1674 switch (str.change_type()) { 1675 case Change_new_type: 1676 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name()); 1677 break; 1678 case Change_new_sub: 1679 if (!WizardMode) { 1680 ++nsup; 1681 } else { 1682 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name()); 1683 } 1684 break; 1685 case Change_new_impl: 1686 if (!WizardMode) { 1687 ++nint; 1688 } else { 1689 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name()); 1690 } 1691 break; 1692 } 1693 } 1694 if (nsup + nint != 0) { 1695 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint); 1696 } 1697 } 1698 1699 void DepChange::ContextStream::start() { 1700 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL; 1701 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass); 1702 _klass = new_type; 1703 _ti_base = NULL; 1704 _ti_index = 0; 1705 _ti_limit = 0; 1706 } 1707 1708 bool DepChange::ContextStream::next() { 1709 switch (_change_type) { 1710 case Start_Klass: // initial state; _klass is the new type 1711 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces(); 1712 _ti_index = 0; 1713 _change_type = Change_new_type; 1714 return true; 1715 case Change_new_type: 1716 // fall through: 1717 _change_type = Change_new_sub; 1718 case Change_new_sub: 1719 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277 1720 { 1721 _klass = InstanceKlass::cast(_klass)->super(); 1722 if (_klass != NULL) { 1723 return true; 1724 } 1725 } 1726 // else set up _ti_limit and fall through: 1727 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length(); 1728 _change_type = Change_new_impl; 1729 case Change_new_impl: 1730 if (_ti_index < _ti_limit) { 1731 _klass = _ti_base->at(_ti_index++); 1732 return true; 1733 } 1734 // fall through: 1735 _change_type = NO_CHANGE; // iterator is exhausted 1736 case NO_CHANGE: 1737 break; 1738 default: 1739 ShouldNotReachHere(); 1740 } 1741 return false; 1742 } 1743 1744 void KlassDepChange::initialize() { 1745 // entire transaction must be under this lock: 1746 assert_lock_strong(Compile_lock); 1747 1748 // Mark all dependee and all its superclasses 1749 // Mark transitive interfaces 1750 for (ContextStream str(*this); str.next(); ) { 1751 Klass* d = str.klass(); 1752 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking"); 1753 InstanceKlass::cast(d)->set_is_marked_dependent(true); 1754 } 1755 } 1756 1757 KlassDepChange::~KlassDepChange() { 1758 // Unmark all dependee and all its superclasses 1759 // Unmark transitive interfaces 1760 for (ContextStream str(*this); str.next(); ) { 1761 Klass* d = str.klass(); 1762 InstanceKlass::cast(d)->set_is_marked_dependent(false); 1763 } 1764 } 1765 1766 bool KlassDepChange::involves_context(Klass* k) { 1767 if (k == NULL || !k->oop_is_instance()) { 1768 return false; 1769 } 1770 InstanceKlass* ik = InstanceKlass::cast(k); 1771 bool is_contained = ik->is_marked_dependent(); 1772 assert(is_contained == new_type()->is_subtype_of(k), 1773 "correct marking of potential context types"); 1774 return is_contained; 1775 } 1776 1777 #ifndef PRODUCT 1778 void Dependencies::print_statistics() { 1779 if (deps_find_witness_print != 0) { 1780 // Call one final time, to flush out the data. 1781 deps_find_witness_print = -1; 1782 count_find_witness_calls(); 1783 } 1784 } 1785 #endif