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