1 /* 2 * Copyright (c) 2005, 2012, 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::cast((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 Klass::cast(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 int nargs = argument_count(); 573 DepArgument args[max_arg_count]; 574 for (int j = 0; j < nargs; j++) { 575 if (type() == call_site_target_value) { 576 args[j] = argument_oop(j); 577 } else { 578 args[j] = argument(j); 579 } 580 } 581 if (_deps != NULL && _deps->log() != NULL) { 582 Dependencies::write_dependency_to(_deps->log(), 583 type(), nargs, args, witness); 584 } else { 585 Dependencies::write_dependency_to(xtty, 586 type(), nargs, args, witness); 587 } 588 } 589 590 void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose) { 591 int nargs = argument_count(); 592 DepArgument args[max_arg_count]; 593 for (int j = 0; j < nargs; j++) { 594 args[j] = argument(j); 595 } 596 Dependencies::print_dependency(type(), nargs, args, witness); 597 if (verbose) { 598 if (_code != NULL) { 599 tty->print(" code: "); 600 _code->print_value_on(tty); 601 tty->cr(); 602 } 603 } 604 } 605 606 607 /// Dependency stream support (decodes dependencies from an nmethod): 608 609 #ifdef ASSERT 610 void Dependencies::DepStream::initial_asserts(size_t byte_limit) { 611 assert(must_be_in_vm(), "raw oops here"); 612 _byte_limit = byte_limit; 613 _type = (DepType)(end_marker-1); // defeat "already at end" assert 614 assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other"); 615 } 616 #endif //ASSERT 617 618 bool Dependencies::DepStream::next() { 619 assert(_type != end_marker, "already at end"); 620 if (_bytes.position() == 0 && _code != NULL 621 && _code->dependencies_size() == 0) { 622 // Method has no dependencies at all. 623 return false; 624 } 625 int code_byte = (_bytes.read_byte() & 0xFF); 626 if (code_byte == end_marker) { 627 DEBUG_ONLY(_type = end_marker); 628 return false; 629 } else { 630 int ctxk_bit = (code_byte & Dependencies::default_context_type_bit); 631 code_byte -= ctxk_bit; 632 DepType dept = (DepType)code_byte; 633 _type = dept; 634 Dependencies::check_valid_dependency_type(dept); 635 int stride = _dep_args[dept]; 636 assert(stride == dep_args(dept), "sanity"); 637 int skipj = -1; 638 if (ctxk_bit != 0) { 639 skipj = 0; // currently the only context argument is at zero 640 assert(skipj == dep_context_arg(dept), "zero arg always ctxk"); 641 } 642 for (int j = 0; j < stride; j++) { 643 _xi[j] = (j == skipj)? 0: _bytes.read_int(); 644 } 645 DEBUG_ONLY(_xi[stride] = -1); // help detect overruns 646 return true; 647 } 648 } 649 650 inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) { 651 Metadata* o = NULL; 652 if (_code != NULL) { 653 o = _code->metadata_at(i); 654 } else { 655 o = _deps->oop_recorder()->metadata_at(i); 656 } 657 assert(o == NULL || o->is_metadata(), 658 err_msg("Should be perm " PTR_FORMAT, o)); 659 return o; 660 } 661 662 inline oop Dependencies::DepStream::recorded_oop_at(int i) { 663 return (_code != NULL) 664 ? _code->oop_at(i) 665 : JNIHandles::resolve(_deps->oop_recorder()->oop_at(i)); 666 } 667 668 Metadata* Dependencies::DepStream::argument(int i) { 669 Metadata* result = recorded_metadata_at(argument_index(i)); 670 671 if (result == NULL) { // Explicit context argument can be compressed 672 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 673 if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) { 674 result = ctxk_encoded_as_null(type(), argument(ctxkj+1)); 675 } 676 } 677 678 assert(result == NULL || result->is_klass() || result->is_method(), "must be"); 679 return result; 680 } 681 682 oop Dependencies::DepStream::argument_oop(int i) { 683 oop result = recorded_oop_at(argument_index(i)); 684 assert(result == NULL || result->is_oop(), "must be"); 685 return result; 686 } 687 688 Klass* Dependencies::DepStream::context_type() { 689 assert(must_be_in_vm(), "raw oops here"); 690 691 // Most dependencies have an explicit context type argument. 692 { 693 int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg 694 if (ctxkj >= 0) { 695 Metadata* k = argument(ctxkj); 696 assert(k != NULL && k->is_klass(), "type check"); 697 return (Klass*)k; 698 } 699 } 700 701 // Some dependencies are using the klass of the first object 702 // argument as implicit context type (e.g. call_site_target_value). 703 { 704 int ctxkj = dep_implicit_context_arg(type()); 705 if (ctxkj >= 0) { 706 Klass* k = argument_oop(ctxkj)->klass(); 707 assert(k != NULL && k->is_klass(), "type check"); 708 return (Klass*) k; 709 } 710 } 711 712 // And some dependencies don't have a context type at all, 713 // e.g. evol_method. 714 return NULL; 715 } 716 717 /// Checking dependencies: 718 719 // This hierarchy walker inspects subtypes of a given type, 720 // trying to find a "bad" class which breaks a dependency. 721 // Such a class is called a "witness" to the broken dependency. 722 // While searching around, we ignore "participants", which 723 // are already known to the dependency. 724 class ClassHierarchyWalker { 725 public: 726 enum { PARTICIPANT_LIMIT = 3 }; 727 728 private: 729 // optional method descriptor to check for: 730 Symbol* _name; 731 Symbol* _signature; 732 733 // special classes which are not allowed to be witnesses: 734 Klass* _participants[PARTICIPANT_LIMIT+1]; 735 int _num_participants; 736 737 // cache of method lookups 738 Method* _found_methods[PARTICIPANT_LIMIT+1]; 739 740 // if non-zero, tells how many witnesses to convert to participants 741 int _record_witnesses; 742 743 void initialize(Klass* participant) { 744 _record_witnesses = 0; 745 _participants[0] = participant; 746 _found_methods[0] = NULL; 747 _num_participants = 0; 748 if (participant != NULL) { 749 // Terminating NULL. 750 _participants[1] = NULL; 751 _found_methods[1] = NULL; 752 _num_participants = 1; 753 } 754 } 755 756 void initialize_from_method(Method* m) { 757 assert(m != NULL && m->is_method(), "sanity"); 758 _name = m->name(); 759 _signature = m->signature(); 760 } 761 762 public: 763 // The walker is initialized to recognize certain methods and/or types 764 // as friendly participants. 765 ClassHierarchyWalker(Klass* participant, Method* m) { 766 initialize_from_method(m); 767 initialize(participant); 768 } 769 ClassHierarchyWalker(Method* m) { 770 initialize_from_method(m); 771 initialize(NULL); 772 } 773 ClassHierarchyWalker(Klass* participant = NULL) { 774 _name = NULL; 775 _signature = NULL; 776 initialize(participant); 777 } 778 779 // This is common code for two searches: One for concrete subtypes, 780 // the other for concrete method implementations and overrides. 781 bool doing_subtype_search() { 782 return _name == NULL; 783 } 784 785 int num_participants() { return _num_participants; } 786 Klass* participant(int n) { 787 assert((uint)n <= (uint)_num_participants, "oob"); 788 return _participants[n]; 789 } 790 791 // Note: If n==num_participants, returns NULL. 792 Method* found_method(int n) { 793 assert((uint)n <= (uint)_num_participants, "oob"); 794 Method* fm = _found_methods[n]; 795 assert(n == _num_participants || fm != NULL, "proper usage"); 796 assert(fm == NULL || fm->method_holder() == _participants[n], "sanity"); 797 return fm; 798 } 799 800 #ifdef ASSERT 801 // Assert that m is inherited into ctxk, without intervening overrides. 802 // (May return true even if this is not true, in corner cases where we punt.) 803 bool check_method_context(Klass* ctxk, Method* m) { 804 if (m->method_holder() == ctxk) 805 return true; // Quick win. 806 if (m->is_private()) 807 return false; // Quick lose. Should not happen. 808 if (!(m->is_public() || m->is_protected())) 809 // The override story is complex when packages get involved. 810 return true; // Must punt the assertion to true. 811 Klass* k = Klass::cast(ctxk); 812 Method* lm = k->lookup_method(m->name(), m->signature()); 813 if (lm == NULL && k->oop_is_instance()) { 814 // It might be an abstract interface method, devoid of mirandas. 815 lm = ((InstanceKlass*)k)->lookup_method_in_all_interfaces(m->name(), 816 m->signature()); 817 } 818 if (lm == m) 819 // Method m is inherited into ctxk. 820 return true; 821 if (lm != NULL) { 822 if (!(lm->is_public() || lm->is_protected())) { 823 // Method is [package-]private, so the override story is complex. 824 return true; // Must punt the assertion to true. 825 } 826 if (lm->is_static()) { 827 // Static methods don't override non-static so punt 828 return true; 829 } 830 if ( !Dependencies::is_concrete_method(lm) 831 && !Dependencies::is_concrete_method(m) 832 && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder())) 833 // Method m is overridden by lm, but both are non-concrete. 834 return true; 835 } 836 ResourceMark rm; 837 tty->print_cr("Dependency method not found in the associated context:"); 838 tty->print_cr(" context = %s", Klass::cast(ctxk)->external_name()); 839 tty->print( " method = "); m->print_short_name(tty); tty->cr(); 840 if (lm != NULL) { 841 tty->print( " found = "); lm->print_short_name(tty); tty->cr(); 842 } 843 return false; 844 } 845 #endif 846 847 void add_participant(Klass* participant) { 848 assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob"); 849 int np = _num_participants++; 850 _participants[np] = participant; 851 _participants[np+1] = NULL; 852 _found_methods[np+1] = NULL; 853 } 854 855 void record_witnesses(int add) { 856 if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT; 857 assert(_num_participants + add < PARTICIPANT_LIMIT, "oob"); 858 _record_witnesses = add; 859 } 860 861 bool is_witness(Klass* k) { 862 if (doing_subtype_search()) { 863 return Dependencies::is_concrete_klass(k); 864 } else { 865 Method* m = InstanceKlass::cast(k)->find_method(_name, _signature); 866 if (m == NULL || !Dependencies::is_concrete_method(m)) return false; 867 _found_methods[_num_participants] = m; 868 // Note: If add_participant(k) is called, 869 // the method m will already be memoized for it. 870 return true; 871 } 872 } 873 874 bool is_participant(Klass* k) { 875 if (k == _participants[0]) { 876 return true; 877 } else if (_num_participants <= 1) { 878 return false; 879 } else { 880 return in_list(k, &_participants[1]); 881 } 882 } 883 bool ignore_witness(Klass* witness) { 884 if (_record_witnesses == 0) { 885 return false; 886 } else { 887 --_record_witnesses; 888 add_participant(witness); 889 return true; 890 } 891 } 892 static bool in_list(Klass* x, Klass** list) { 893 for (int i = 0; ; i++) { 894 Klass* y = list[i]; 895 if (y == NULL) break; 896 if (y == x) return true; 897 } 898 return false; // not in list 899 } 900 901 private: 902 // the actual search method: 903 Klass* find_witness_anywhere(Klass* context_type, 904 bool participants_hide_witnesses, 905 bool top_level_call = true); 906 // the spot-checking version: 907 Klass* find_witness_in(KlassDepChange& changes, 908 Klass* context_type, 909 bool participants_hide_witnesses); 910 public: 911 Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) { 912 assert(doing_subtype_search(), "must set up a subtype search"); 913 // When looking for unexpected concrete types, 914 // do not look beneath expected ones. 915 const bool participants_hide_witnesses = true; 916 // CX > CC > C' is OK, even if C' is new. 917 // CX > { CC, C' } is not OK if C' is new, and C' is the witness. 918 if (changes != NULL) { 919 return find_witness_in(*changes, context_type, participants_hide_witnesses); 920 } else { 921 return find_witness_anywhere(context_type, participants_hide_witnesses); 922 } 923 } 924 Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) { 925 assert(!doing_subtype_search(), "must set up a method definer search"); 926 // When looking for unexpected concrete methods, 927 // look beneath expected ones, to see if there are overrides. 928 const bool participants_hide_witnesses = true; 929 // CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness. 930 if (changes != NULL) { 931 return find_witness_in(*changes, context_type, !participants_hide_witnesses); 932 } else { 933 return find_witness_anywhere(context_type, !participants_hide_witnesses); 934 } 935 } 936 }; 937 938 #ifndef PRODUCT 939 static int deps_find_witness_calls = 0; 940 static int deps_find_witness_steps = 0; 941 static int deps_find_witness_recursions = 0; 942 static int deps_find_witness_singles = 0; 943 static int deps_find_witness_print = 0; // set to -1 to force a final print 944 static bool count_find_witness_calls() { 945 if (TraceDependencies || LogCompilation) { 946 int pcount = deps_find_witness_print + 1; 947 bool final_stats = (pcount == 0); 948 bool initial_call = (pcount == 1); 949 bool occasional_print = ((pcount & ((1<<10) - 1)) == 0); 950 if (pcount < 0) pcount = 1; // crude overflow protection 951 deps_find_witness_print = pcount; 952 if (VerifyDependencies && initial_call) { 953 tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies"); 954 } 955 if (occasional_print || final_stats) { 956 // Every now and then dump a little info about dependency searching. 957 if (xtty != NULL) { 958 ttyLocker ttyl; 959 xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'", 960 deps_find_witness_calls, 961 deps_find_witness_steps, 962 deps_find_witness_recursions, 963 deps_find_witness_singles); 964 } 965 if (final_stats || (TraceDependencies && WizardMode)) { 966 ttyLocker ttyl; 967 tty->print_cr("Dependency check (find_witness) " 968 "calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d", 969 deps_find_witness_calls, 970 deps_find_witness_steps, 971 (double)deps_find_witness_steps / deps_find_witness_calls, 972 deps_find_witness_recursions, 973 deps_find_witness_singles); 974 } 975 } 976 return true; 977 } 978 return false; 979 } 980 #else 981 #define count_find_witness_calls() (0) 982 #endif //PRODUCT 983 984 985 Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes, 986 Klass* context_type, 987 bool participants_hide_witnesses) { 988 assert(changes.involves_context(context_type), "irrelevant dependency"); 989 Klass* new_type = changes.new_type(); 990 991 count_find_witness_calls(); 992 NOT_PRODUCT(deps_find_witness_singles++); 993 994 // Current thread must be in VM (not native mode, as in CI): 995 assert(must_be_in_vm(), "raw oops here"); 996 // Must not move the class hierarchy during this check: 997 assert_locked_or_safepoint(Compile_lock); 998 999 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1000 if (nof_impls > 1) { 1001 // Avoid this case: *I.m > { A.m, C }; B.m > C 1002 // %%% Until this is fixed more systematically, bail out. 1003 // See corresponding comment in find_witness_anywhere. 1004 return context_type; 1005 } 1006 1007 assert(!is_participant(new_type), "only old classes are participants"); 1008 if (participants_hide_witnesses) { 1009 // If the new type is a subtype of a participant, we are done. 1010 for (int i = 0; i < num_participants(); i++) { 1011 Klass* part = participant(i); 1012 if (part == NULL) continue; 1013 assert(changes.involves_context(part) == Klass::cast(new_type)->is_subtype_of(part), 1014 "correct marking of participants, b/c new_type is unique"); 1015 if (changes.involves_context(part)) { 1016 // new guy is protected from this check by previous participant 1017 return NULL; 1018 } 1019 } 1020 } 1021 1022 if (is_witness(new_type) && 1023 !ignore_witness(new_type)) { 1024 return new_type; 1025 } 1026 1027 return NULL; 1028 } 1029 1030 1031 // Walk hierarchy under a context type, looking for unexpected types. 1032 // Do not report participant types, and recursively walk beneath 1033 // them only if participants_hide_witnesses is false. 1034 // If top_level_call is false, skip testing the context type, 1035 // because the caller has already considered it. 1036 Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type, 1037 bool participants_hide_witnesses, 1038 bool top_level_call) { 1039 // Current thread must be in VM (not native mode, as in CI): 1040 assert(must_be_in_vm(), "raw oops here"); 1041 // Must not move the class hierarchy during this check: 1042 assert_locked_or_safepoint(Compile_lock); 1043 1044 bool do_counts = count_find_witness_calls(); 1045 1046 // Check the root of the sub-hierarchy first. 1047 if (top_level_call) { 1048 if (do_counts) { 1049 NOT_PRODUCT(deps_find_witness_calls++); 1050 NOT_PRODUCT(deps_find_witness_steps++); 1051 } 1052 if (is_participant(context_type)) { 1053 if (participants_hide_witnesses) return NULL; 1054 // else fall through to search loop... 1055 } else if (is_witness(context_type) && !ignore_witness(context_type)) { 1056 // The context is an abstract class or interface, to start with. 1057 return context_type; 1058 } 1059 } 1060 1061 // Now we must check each implementor and each subclass. 1062 // Use a short worklist to avoid blowing the stack. 1063 // Each worklist entry is a *chain* of subklass siblings to process. 1064 const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit 1065 Klass* chains[CHAINMAX]; 1066 int chaini = 0; // index into worklist 1067 Klass* chain; // scratch variable 1068 #define ADD_SUBCLASS_CHAIN(k) { \ 1069 assert(chaini < CHAINMAX, "oob"); \ 1070 chain = InstanceKlass::cast(k)->subklass(); \ 1071 if (chain != NULL) chains[chaini++] = chain; } 1072 1073 // Look for non-abstract subclasses. 1074 // (Note: Interfaces do not have subclasses.) 1075 ADD_SUBCLASS_CHAIN(context_type); 1076 1077 // If it is an interface, search its direct implementors. 1078 // (Their subclasses are additional indirect implementors. 1079 // See InstanceKlass::add_implementor.) 1080 // (Note: nof_implementors is always zero for non-interfaces.) 1081 int nof_impls = InstanceKlass::cast(context_type)->nof_implementors(); 1082 if (nof_impls > 1) { 1083 // Avoid this case: *I.m > { A.m, C }; B.m > C 1084 // Here, I.m has 2 concrete implementations, but m appears unique 1085 // as A.m, because the search misses B.m when checking C. 1086 // The inherited method B.m was getting missed by the walker 1087 // when interface 'I' was the starting point. 1088 // %%% Until this is fixed more systematically, bail out. 1089 // (Old CHA had the same limitation.) 1090 return context_type; 1091 } 1092 if (nof_impls > 0) { 1093 Klass* impl = InstanceKlass::cast(context_type)->implementor(); 1094 assert(impl != NULL, "just checking"); 1095 // If impl is the same as the context_type, then more than one 1096 // implementor has seen. No exact info in this case. 1097 if (impl == context_type) { 1098 return context_type; // report an inexact witness to this sad affair 1099 } 1100 if (do_counts) 1101 { NOT_PRODUCT(deps_find_witness_steps++); } 1102 if (is_participant(impl)) { 1103 if (!participants_hide_witnesses) { 1104 ADD_SUBCLASS_CHAIN(impl); 1105 } 1106 } else if (is_witness(impl) && !ignore_witness(impl)) { 1107 return impl; 1108 } else { 1109 ADD_SUBCLASS_CHAIN(impl); 1110 } 1111 } 1112 1113 // Recursively process each non-trivial sibling chain. 1114 while (chaini > 0) { 1115 Klass* chain = chains[--chaini]; 1116 for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) { 1117 if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); } 1118 if (is_participant(sub)) { 1119 if (participants_hide_witnesses) continue; 1120 // else fall through to process this guy's subclasses 1121 } else if (is_witness(sub) && !ignore_witness(sub)) { 1122 return sub; 1123 } 1124 if (chaini < (VerifyDependencies? 2: CHAINMAX)) { 1125 // Fast path. (Partially disabled if VerifyDependencies.) 1126 ADD_SUBCLASS_CHAIN(sub); 1127 } else { 1128 // Worklist overflow. Do a recursive call. Should be rare. 1129 // The recursive call will have its own worklist, of course. 1130 // (Note that sub has already been tested, so that there is 1131 // no need for the recursive call to re-test. That's handy, 1132 // since the recursive call sees sub as the context_type.) 1133 if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); } 1134 Klass* witness = find_witness_anywhere(sub, 1135 participants_hide_witnesses, 1136 /*top_level_call=*/ false); 1137 if (witness != NULL) return witness; 1138 } 1139 } 1140 } 1141 1142 // No witness found. The dependency remains unbroken. 1143 return NULL; 1144 #undef ADD_SUBCLASS_CHAIN 1145 } 1146 1147 1148 bool Dependencies::is_concrete_klass(Klass* k) { 1149 if (Klass::cast(k)->is_abstract()) return false; 1150 // %%% We could treat classes which are concrete but 1151 // have not yet been instantiated as virtually abstract. 1152 // This would require a deoptimization barrier on first instantiation. 1153 //if (k->is_not_instantiated()) return false; 1154 return true; 1155 } 1156 1157 bool Dependencies::is_concrete_method(Method* m) { 1158 // Statics are irrelevant to virtual call sites. 1159 if (m->is_static()) return false; 1160 1161 // We could also return false if m does not yet appear to be 1162 // executed, if the VM version supports this distinction also. 1163 return !m->is_abstract(); 1164 } 1165 1166 1167 Klass* Dependencies::find_finalizable_subclass(Klass* k) { 1168 if (k->is_interface()) return NULL; 1169 if (k->has_finalizer()) return k; 1170 k = k->subklass(); 1171 while (k != NULL) { 1172 Klass* result = find_finalizable_subclass(k); 1173 if (result != NULL) return result; 1174 k = k->next_sibling(); 1175 } 1176 return NULL; 1177 } 1178 1179 1180 bool Dependencies::is_concrete_klass(ciInstanceKlass* k) { 1181 if (k->is_abstract()) return false; 1182 // We could also return false if k does not yet appear to be 1183 // instantiated, if the VM version supports this distinction also. 1184 //if (k->is_not_instantiated()) return false; 1185 return true; 1186 } 1187 1188 bool Dependencies::is_concrete_method(ciMethod* m) { 1189 // Statics are irrelevant to virtual call sites. 1190 if (m->is_static()) return false; 1191 1192 // We could also return false if m does not yet appear to be 1193 // executed, if the VM version supports this distinction also. 1194 return !m->is_abstract(); 1195 } 1196 1197 1198 bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) { 1199 return k->has_finalizable_subclass(); 1200 } 1201 1202 1203 // Any use of the contents (bytecodes) of a method must be 1204 // marked by an "evol_method" dependency, if those contents 1205 // can change. (Note: A method is always dependent on itself.) 1206 Klass* Dependencies::check_evol_method(Method* m) { 1207 assert(must_be_in_vm(), "raw oops here"); 1208 // Did somebody do a JVMTI RedefineClasses while our backs were turned? 1209 // Or is there a now a breakpoint? 1210 // (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.) 1211 if (m->is_old() 1212 || m->number_of_breakpoints() > 0) { 1213 return m->method_holder(); 1214 } else { 1215 return NULL; 1216 } 1217 } 1218 1219 // This is a strong assertion: It is that the given type 1220 // has no subtypes whatever. It is most useful for 1221 // optimizing checks on reflected types or on array types. 1222 // (Checks on types which are derived from real instances 1223 // can be optimized more strongly than this, because we 1224 // know that the checked type comes from a concrete type, 1225 // and therefore we can disregard abstract types.) 1226 Klass* Dependencies::check_leaf_type(Klass* ctxk) { 1227 assert(must_be_in_vm(), "raw oops here"); 1228 assert_locked_or_safepoint(Compile_lock); 1229 InstanceKlass* ctx = InstanceKlass::cast(ctxk); 1230 Klass* sub = ctx->subklass(); 1231 if (sub != NULL) { 1232 return sub; 1233 } else if (ctx->nof_implementors() != 0) { 1234 // if it is an interface, it must be unimplemented 1235 // (if it is not an interface, nof_implementors is always zero) 1236 Klass* impl = ctx->implementor(); 1237 assert(impl != NULL, "must be set"); 1238 return impl; 1239 } else { 1240 return NULL; 1241 } 1242 } 1243 1244 // Test the assertion that conck is the only concrete subtype* of ctxk. 1245 // The type conck itself is allowed to have have further concrete subtypes. 1246 // This allows the compiler to narrow occurrences of ctxk by conck, 1247 // when dealing with the types of actual instances. 1248 Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk, 1249 Klass* conck, 1250 KlassDepChange* changes) { 1251 ClassHierarchyWalker wf(conck); 1252 return wf.find_witness_subtype(ctxk, changes); 1253 } 1254 1255 // If a non-concrete class has no concrete subtypes, it is not (yet) 1256 // instantiatable. This can allow the compiler to make some paths go 1257 // dead, if they are gated by a test of the type. 1258 Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk, 1259 KlassDepChange* changes) { 1260 // Find any concrete subtype, with no participants: 1261 ClassHierarchyWalker wf; 1262 return wf.find_witness_subtype(ctxk, changes); 1263 } 1264 1265 1266 // If a concrete class has no concrete subtypes, it can always be 1267 // exactly typed. This allows the use of a cheaper type test. 1268 Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk, 1269 KlassDepChange* changes) { 1270 // Find any concrete subtype, with only the ctxk as participant: 1271 ClassHierarchyWalker wf(ctxk); 1272 return wf.find_witness_subtype(ctxk, changes); 1273 } 1274 1275 1276 // Find the unique concrete proper subtype of ctxk, or NULL if there 1277 // is more than one concrete proper subtype. If there are no concrete 1278 // proper subtypes, return ctxk itself, whether it is concrete or not. 1279 // The returned subtype is allowed to have have further concrete subtypes. 1280 // That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }. 1281 Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) { 1282 ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking. 1283 wf.record_witnesses(1); // Record one other witness when walking. 1284 Klass* wit = wf.find_witness_subtype(ctxk); 1285 if (wit != NULL) return NULL; // Too many witnesses. 1286 Klass* conck = wf.participant(0); 1287 if (conck == NULL) { 1288 #ifndef PRODUCT 1289 // Make sure the dependency mechanism will pass this discovery: 1290 if (VerifyDependencies) { 1291 // Turn off dependency tracing while actually testing deps. 1292 FlagSetting fs(TraceDependencies, false); 1293 if (!Dependencies::is_concrete_klass(ctxk)) { 1294 guarantee(NULL == 1295 (void *)check_abstract_with_no_concrete_subtype(ctxk), 1296 "verify dep."); 1297 } else { 1298 guarantee(NULL == 1299 (void *)check_concrete_with_no_concrete_subtype(ctxk), 1300 "verify dep."); 1301 } 1302 } 1303 #endif //PRODUCT 1304 return ctxk; // Return ctxk as a flag for "no subtypes". 1305 } else { 1306 #ifndef PRODUCT 1307 // Make sure the dependency mechanism will pass this discovery: 1308 if (VerifyDependencies) { 1309 // Turn off dependency tracing while actually testing deps. 1310 FlagSetting fs(TraceDependencies, false); 1311 if (!Dependencies::is_concrete_klass(ctxk)) { 1312 guarantee(NULL == (void *) 1313 check_abstract_with_unique_concrete_subtype(ctxk, conck), 1314 "verify dep."); 1315 } 1316 } 1317 #endif //PRODUCT 1318 return conck; 1319 } 1320 } 1321 1322 // Test the assertion that the k[12] are the only concrete subtypes of ctxk, 1323 // except possibly for further subtypes of k[12] themselves. 1324 // The context type must be abstract. The types k1 and k2 are themselves 1325 // allowed to have further concrete subtypes. 1326 Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes( 1327 Klass* ctxk, 1328 Klass* k1, 1329 Klass* k2, 1330 KlassDepChange* changes) { 1331 ClassHierarchyWalker wf; 1332 wf.add_participant(k1); 1333 wf.add_participant(k2); 1334 return wf.find_witness_subtype(ctxk, changes); 1335 } 1336 1337 // Search ctxk for concrete implementations. If there are klen or fewer, 1338 // pack them into the given array and return the number. 1339 // Otherwise, return -1, meaning the given array would overflow. 1340 // (Note that a return of 0 means there are exactly no concrete subtypes.) 1341 // In this search, if ctxk is concrete, it will be reported alone. 1342 // For any type CC reported, no proper subtypes of CC will be reported. 1343 int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk, 1344 int klen, 1345 Klass* karray[]) { 1346 ClassHierarchyWalker wf; 1347 wf.record_witnesses(klen); 1348 Klass* wit = wf.find_witness_subtype(ctxk); 1349 if (wit != NULL) return -1; // Too many witnesses. 1350 int num = wf.num_participants(); 1351 assert(num <= klen, "oob"); 1352 // Pack the result array with the good news. 1353 for (int i = 0; i < num; i++) 1354 karray[i] = wf.participant(i); 1355 #ifndef PRODUCT 1356 // Make sure the dependency mechanism will pass this discovery: 1357 if (VerifyDependencies) { 1358 // Turn off dependency tracing while actually testing deps. 1359 FlagSetting fs(TraceDependencies, false); 1360 switch (Dependencies::is_concrete_klass(ctxk)? -1: num) { 1361 case -1: // ctxk was itself concrete 1362 guarantee(num == 1 && karray[0] == ctxk, "verify dep."); 1363 break; 1364 case 0: 1365 guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk), 1366 "verify dep."); 1367 break; 1368 case 1: 1369 guarantee(NULL == (void *) 1370 check_abstract_with_unique_concrete_subtype(ctxk, karray[0]), 1371 "verify dep."); 1372 break; 1373 case 2: 1374 guarantee(NULL == (void *) 1375 check_abstract_with_exclusive_concrete_subtypes(ctxk, 1376 karray[0], 1377 karray[1]), 1378 "verify dep."); 1379 break; 1380 default: 1381 ShouldNotReachHere(); // klen > 2 yet supported 1382 } 1383 } 1384 #endif //PRODUCT 1385 return num; 1386 } 1387 1388 // If a class (or interface) has a unique concrete method uniqm, return NULL. 1389 // Otherwise, return a class that contains an interfering method. 1390 Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm, 1391 KlassDepChange* changes) { 1392 // Here is a missing optimization: If uniqm->is_final(), 1393 // we don't really need to search beneath it for overrides. 1394 // This is probably not important, since we don't use dependencies 1395 // to track final methods. (They can't be "definalized".) 1396 ClassHierarchyWalker wf(uniqm->method_holder(), uniqm); 1397 return wf.find_witness_definer(ctxk, changes); 1398 } 1399 1400 // Find the set of all non-abstract methods under ctxk that match m. 1401 // (The method m must be defined or inherited in ctxk.) 1402 // Include m itself in the set, unless it is abstract. 1403 // If this set has exactly one element, return that element. 1404 Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) { 1405 ClassHierarchyWalker wf(m); 1406 assert(wf.check_method_context(ctxk, m), "proper context"); 1407 wf.record_witnesses(1); 1408 Klass* wit = wf.find_witness_definer(ctxk); 1409 if (wit != NULL) return NULL; // Too many witnesses. 1410 Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0. 1411 if (Dependencies::is_concrete_method(m)) { 1412 if (fm == NULL) { 1413 // It turns out that m was always the only implementation. 1414 fm = m; 1415 } else if (fm != m) { 1416 // Two conflicting implementations after all. 1417 // (This can happen if m is inherited into ctxk and fm overrides it.) 1418 return NULL; 1419 } 1420 } 1421 #ifndef PRODUCT 1422 // Make sure the dependency mechanism will pass this discovery: 1423 if (VerifyDependencies && fm != NULL) { 1424 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm), 1425 "verify dep."); 1426 } 1427 #endif //PRODUCT 1428 return fm; 1429 } 1430 1431 Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk, 1432 Method* m1, 1433 Method* m2, 1434 KlassDepChange* changes) { 1435 ClassHierarchyWalker wf(m1); 1436 wf.add_participant(m1->method_holder()); 1437 wf.add_participant(m2->method_holder()); 1438 return wf.find_witness_definer(ctxk, changes); 1439 } 1440 1441 // Find the set of all non-abstract methods under ctxk that match m[0]. 1442 // (The method m[0] must be defined or inherited in ctxk.) 1443 // Include m itself in the set, unless it is abstract. 1444 // Fill the given array m[0..(mlen-1)] with this set, and return the length. 1445 // (The length may be zero if no concrete methods are found anywhere.) 1446 // If there are too many concrete methods to fit in marray, return -1. 1447 int Dependencies::find_exclusive_concrete_methods(Klass* ctxk, 1448 int mlen, 1449 Method* marray[]) { 1450 Method* m0 = marray[0]; 1451 ClassHierarchyWalker wf(m0); 1452 assert(wf.check_method_context(ctxk, m0), "proper context"); 1453 wf.record_witnesses(mlen); 1454 bool participants_hide_witnesses = true; 1455 Klass* wit = wf.find_witness_definer(ctxk); 1456 if (wit != NULL) return -1; // Too many witnesses. 1457 int num = wf.num_participants(); 1458 assert(num <= mlen, "oob"); 1459 // Keep track of whether m is also part of the result set. 1460 int mfill = 0; 1461 assert(marray[mfill] == m0, "sanity"); 1462 if (Dependencies::is_concrete_method(m0)) 1463 mfill++; // keep m0 as marray[0], the first result 1464 for (int i = 0; i < num; i++) { 1465 Method* fm = wf.found_method(i); 1466 if (fm == m0) continue; // Already put this guy in the list. 1467 if (mfill == mlen) { 1468 return -1; // Oops. Too many methods after all! 1469 } 1470 marray[mfill++] = fm; 1471 } 1472 #ifndef PRODUCT 1473 // Make sure the dependency mechanism will pass this discovery: 1474 if (VerifyDependencies) { 1475 // Turn off dependency tracing while actually testing deps. 1476 FlagSetting fs(TraceDependencies, false); 1477 switch (mfill) { 1478 case 1: 1479 guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]), 1480 "verify dep."); 1481 break; 1482 case 2: 1483 guarantee(NULL == (void *) 1484 check_exclusive_concrete_methods(ctxk, marray[0], marray[1]), 1485 "verify dep."); 1486 break; 1487 default: 1488 ShouldNotReachHere(); // mlen > 2 yet supported 1489 } 1490 } 1491 #endif //PRODUCT 1492 return mfill; 1493 } 1494 1495 1496 Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) { 1497 Klass* search_at = ctxk; 1498 if (changes != NULL) 1499 search_at = changes->new_type(); // just look at the new bit 1500 return find_finalizable_subclass(search_at); 1501 } 1502 1503 1504 Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) { 1505 assert(call_site ->is_a(SystemDictionary::CallSite_klass()), "sanity"); 1506 assert(method_handle->is_a(SystemDictionary::MethodHandle_klass()), "sanity"); 1507 if (changes == NULL) { 1508 // Validate all CallSites 1509 if (java_lang_invoke_CallSite::target(call_site) != method_handle) 1510 return call_site->klass(); // assertion failed 1511 } else { 1512 // Validate the given CallSite 1513 if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) { 1514 assert(method_handle != changes->method_handle(), "must be"); 1515 return call_site->klass(); // assertion failed 1516 } 1517 } 1518 return NULL; // assertion still valid 1519 } 1520 1521 1522 void Dependencies::DepStream::trace_and_log_witness(Klass* witness) { 1523 if (witness != NULL) { 1524 if (TraceDependencies) { 1525 print_dependency(witness, /*verbose=*/ true); 1526 } 1527 // The following is a no-op unless logging is enabled: 1528 log_dependency(witness); 1529 } 1530 } 1531 1532 1533 Klass* Dependencies::DepStream::check_klass_dependency(KlassDepChange* changes) { 1534 assert_locked_or_safepoint(Compile_lock); 1535 Dependencies::check_valid_dependency_type(type()); 1536 1537 Klass* witness = NULL; 1538 switch (type()) { 1539 case evol_method: 1540 witness = check_evol_method(method_argument(0)); 1541 break; 1542 case leaf_type: 1543 witness = check_leaf_type(context_type()); 1544 break; 1545 case abstract_with_unique_concrete_subtype: 1546 witness = check_abstract_with_unique_concrete_subtype(context_type(), type_argument(1), changes); 1547 break; 1548 case abstract_with_no_concrete_subtype: 1549 witness = check_abstract_with_no_concrete_subtype(context_type(), changes); 1550 break; 1551 case concrete_with_no_concrete_subtype: 1552 witness = check_concrete_with_no_concrete_subtype(context_type(), changes); 1553 break; 1554 case unique_concrete_method: 1555 witness = check_unique_concrete_method(context_type(), method_argument(1), changes); 1556 break; 1557 case abstract_with_exclusive_concrete_subtypes_2: 1558 witness = check_abstract_with_exclusive_concrete_subtypes(context_type(), type_argument(1), type_argument(2), changes); 1559 break; 1560 case exclusive_concrete_methods_2: 1561 witness = check_exclusive_concrete_methods(context_type(), method_argument(1), method_argument(2), changes); 1562 break; 1563 case no_finalizable_subclasses: 1564 witness = check_has_no_finalizable_subclasses(context_type(), changes); 1565 break; 1566 default: 1567 witness = NULL; 1568 break; 1569 } 1570 trace_and_log_witness(witness); 1571 return witness; 1572 } 1573 1574 1575 Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* changes) { 1576 assert_locked_or_safepoint(Compile_lock); 1577 Dependencies::check_valid_dependency_type(type()); 1578 1579 Klass* witness = NULL; 1580 switch (type()) { 1581 case call_site_target_value: 1582 witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes); 1583 break; 1584 default: 1585 witness = NULL; 1586 break; 1587 } 1588 trace_and_log_witness(witness); 1589 return witness; 1590 } 1591 1592 1593 Klass* Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) { 1594 // Handle klass dependency 1595 if (changes.is_klass_change() && changes.as_klass_change()->involves_context(context_type())) 1596 return check_klass_dependency(changes.as_klass_change()); 1597 1598 // Handle CallSite dependency 1599 if (changes.is_call_site_change()) 1600 return check_call_site_dependency(changes.as_call_site_change()); 1601 1602 // irrelevant dependency; skip it 1603 return NULL; 1604 } 1605 1606 1607 void DepChange::print() { 1608 int nsup = 0, nint = 0; 1609 for (ContextStream str(*this); str.next(); ) { 1610 Klass* k = str.klass(); 1611 switch (str.change_type()) { 1612 case Change_new_type: 1613 tty->print_cr(" dependee = %s", InstanceKlass::cast(k)->external_name()); 1614 break; 1615 case Change_new_sub: 1616 if (!WizardMode) { 1617 ++nsup; 1618 } else { 1619 tty->print_cr(" context super = %s", InstanceKlass::cast(k)->external_name()); 1620 } 1621 break; 1622 case Change_new_impl: 1623 if (!WizardMode) { 1624 ++nint; 1625 } else { 1626 tty->print_cr(" context interface = %s", InstanceKlass::cast(k)->external_name()); 1627 } 1628 break; 1629 } 1630 } 1631 if (nsup + nint != 0) { 1632 tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint); 1633 } 1634 } 1635 1636 void DepChange::ContextStream::start() { 1637 Klass* new_type = _changes.is_klass_change() ? _changes.as_klass_change()->new_type() : (Klass*) NULL; 1638 _change_type = (new_type == NULL ? NO_CHANGE : Start_Klass); 1639 _klass = new_type; 1640 _ti_base = NULL; 1641 _ti_index = 0; 1642 _ti_limit = 0; 1643 } 1644 1645 bool DepChange::ContextStream::next() { 1646 switch (_change_type) { 1647 case Start_Klass: // initial state; _klass is the new type 1648 _ti_base = InstanceKlass::cast(_klass)->transitive_interfaces(); 1649 _ti_index = 0; 1650 _change_type = Change_new_type; 1651 return true; 1652 case Change_new_type: 1653 // fall through: 1654 _change_type = Change_new_sub; 1655 case Change_new_sub: 1656 // 6598190: brackets workaround Sun Studio C++ compiler bug 6629277 1657 { 1658 _klass = InstanceKlass::cast(_klass)->super(); 1659 if (_klass != NULL) { 1660 return true; 1661 } 1662 } 1663 // else set up _ti_limit and fall through: 1664 _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length(); 1665 _change_type = Change_new_impl; 1666 case Change_new_impl: 1667 if (_ti_index < _ti_limit) { 1668 _klass = _ti_base->at(_ti_index++); 1669 return true; 1670 } 1671 // fall through: 1672 _change_type = NO_CHANGE; // iterator is exhausted 1673 case NO_CHANGE: 1674 break; 1675 default: 1676 ShouldNotReachHere(); 1677 } 1678 return false; 1679 } 1680 1681 void KlassDepChange::initialize() { 1682 // entire transaction must be under this lock: 1683 assert_lock_strong(Compile_lock); 1684 1685 // Mark all dependee and all its superclasses 1686 // Mark transitive interfaces 1687 for (ContextStream str(*this); str.next(); ) { 1688 Klass* d = str.klass(); 1689 assert(!InstanceKlass::cast(d)->is_marked_dependent(), "checking"); 1690 InstanceKlass::cast(d)->set_is_marked_dependent(true); 1691 } 1692 } 1693 1694 KlassDepChange::~KlassDepChange() { 1695 // Unmark all dependee and all its superclasses 1696 // Unmark transitive interfaces 1697 for (ContextStream str(*this); str.next(); ) { 1698 Klass* d = str.klass(); 1699 InstanceKlass::cast(d)->set_is_marked_dependent(false); 1700 } 1701 } 1702 1703 bool KlassDepChange::involves_context(Klass* k) { 1704 if (k == NULL || !Klass::cast(k)->oop_is_instance()) { 1705 return false; 1706 } 1707 InstanceKlass* ik = InstanceKlass::cast(k); 1708 bool is_contained = ik->is_marked_dependent(); 1709 assert(is_contained == Klass::cast(new_type())->is_subtype_of(k), 1710 "correct marking of potential context types"); 1711 return is_contained; 1712 } 1713 1714 #ifndef PRODUCT 1715 void Dependencies::print_statistics() { 1716 if (deps_find_witness_print != 0) { 1717 // Call one final time, to flush out the data. 1718 deps_find_witness_print = -1; 1719 count_find_witness_calls(); 1720 } 1721 } 1722 #endif