1 /* 2 * Copyright (c) 2015, 2019, 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 "code/compiledIC.hpp" 27 #include "code/compiledMethod.inline.hpp" 28 #include "code/exceptionHandlerTable.hpp" 29 #include "code/scopeDesc.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/icBuffer.hpp" 32 #include "gc/shared/barrierSet.hpp" 33 #include "gc/shared/gcBehaviours.hpp" 34 #include "interpreter/bytecode.inline.hpp" 35 #include "logging/log.hpp" 36 #include "logging/logTag.hpp" 37 #include "memory/resourceArea.hpp" 38 #include "oops/methodData.hpp" 39 #include "oops/method.inline.hpp" 40 #include "prims/methodHandles.hpp" 41 #include "runtime/deoptimization.hpp" 42 #include "runtime/handles.inline.hpp" 43 #include "runtime/mutexLocker.hpp" 44 #include "runtime/sharedRuntime.hpp" 45 46 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, const CodeBlobLayout& layout, 47 int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps, 48 bool caller_must_gc_arguments) 49 : CodeBlob(name, type, layout, frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments), 50 _mark_for_deoptimization_status(not_marked), 51 _method(method), 52 _gc_data(NULL) 53 { 54 init_defaults(); 55 } 56 57 CompiledMethod::CompiledMethod(Method* method, const char* name, CompilerType type, int size, 58 int header_size, CodeBuffer* cb, int frame_complete_offset, int frame_size, 59 OopMapSet* oop_maps, bool caller_must_gc_arguments) 60 : CodeBlob(name, type, CodeBlobLayout((address) this, size, header_size, cb), cb, 61 frame_complete_offset, frame_size, oop_maps, caller_must_gc_arguments), 62 _mark_for_deoptimization_status(not_marked), 63 _method(method), 64 _gc_data(NULL) 65 { 66 init_defaults(); 67 } 68 69 void CompiledMethod::init_defaults() { 70 _has_unsafe_access = 0; 71 _has_method_handle_invokes = 0; 72 _lazy_critical_native = 0; 73 _has_wide_vectors = 0; 74 } 75 76 bool CompiledMethod::is_method_handle_return(address return_pc) { 77 if (!has_method_handle_invokes()) return false; 78 PcDesc* pd = pc_desc_at(return_pc); 79 if (pd == NULL) 80 return false; 81 return pd->is_method_handle_invoke(); 82 } 83 84 // Returns a string version of the method state. 85 const char* CompiledMethod::state() const { 86 int state = get_state(); 87 switch (state) { 88 case not_installed: 89 return "not installed"; 90 case in_use: 91 return "in use"; 92 case not_used: 93 return "not_used"; 94 case not_entrant: 95 return "not_entrant"; 96 case zombie: 97 return "zombie"; 98 case unloaded: 99 return "unloaded"; 100 default: 101 fatal("unexpected method state: %d", state); 102 return NULL; 103 } 104 } 105 106 //----------------------------------------------------------------------------- 107 void CompiledMethod::mark_for_deoptimization(bool inc_recompile_counts) { 108 MutexLocker ml(CompiledMethod_lock->owned_by_self() ? NULL : CompiledMethod_lock, 109 Mutex::_no_safepoint_check_flag); 110 _mark_for_deoptimization_status = (inc_recompile_counts ? deoptimize : deoptimize_noupdate); 111 } 112 113 //----------------------------------------------------------------------------- 114 115 ExceptionCache* CompiledMethod::exception_cache_acquire() const { 116 return OrderAccess::load_acquire(&_exception_cache); 117 } 118 119 void CompiledMethod::add_exception_cache_entry(ExceptionCache* new_entry) { 120 assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock"); 121 assert(new_entry != NULL,"Must be non null"); 122 assert(new_entry->next() == NULL, "Must be null"); 123 124 for (;;) { 125 ExceptionCache *ec = exception_cache(); 126 if (ec != NULL) { 127 Klass* ex_klass = ec->exception_type(); 128 if (!ex_klass->is_loader_alive()) { 129 // We must guarantee that entries are not inserted with new next pointer 130 // edges to ExceptionCache entries with dead klasses, due to bad interactions 131 // with concurrent ExceptionCache cleanup. Therefore, the inserts roll 132 // the head pointer forward to the first live ExceptionCache, so that the new 133 // next pointers always point at live ExceptionCaches, that are not removed due 134 // to concurrent ExceptionCache cleanup. 135 ExceptionCache* next = ec->next(); 136 if (Atomic::cmpxchg(next, &_exception_cache, ec) == ec) { 137 CodeCache::release_exception_cache(ec); 138 } 139 continue; 140 } 141 ec = exception_cache(); 142 if (ec != NULL) { 143 new_entry->set_next(ec); 144 } 145 } 146 if (Atomic::cmpxchg(new_entry, &_exception_cache, ec) == ec) { 147 return; 148 } 149 } 150 } 151 152 void CompiledMethod::clean_exception_cache() { 153 // For each nmethod, only a single thread may call this cleanup function 154 // at the same time, whether called in STW cleanup or concurrent cleanup. 155 // Note that if the GC is processing exception cache cleaning in a concurrent phase, 156 // then a single writer may contend with cleaning up the head pointer to the 157 // first ExceptionCache node that has a Klass* that is alive. That is fine, 158 // as long as there is no concurrent cleanup of next pointers from concurrent writers. 159 // And the concurrent writers do not clean up next pointers, only the head. 160 // Also note that concurent readers will walk through Klass* pointers that are not 161 // alive. That does not cause ABA problems, because Klass* is deleted after 162 // a handshake with all threads, after all stale ExceptionCaches have been 163 // unlinked. That is also when the CodeCache::exception_cache_purge_list() 164 // is deleted, with all ExceptionCache entries that were cleaned concurrently. 165 // That similarly implies that CAS operations on ExceptionCache entries do not 166 // suffer from ABA problems as unlinking and deletion is separated by a global 167 // handshake operation. 168 ExceptionCache* prev = NULL; 169 ExceptionCache* curr = exception_cache_acquire(); 170 171 while (curr != NULL) { 172 ExceptionCache* next = curr->next(); 173 174 if (!curr->exception_type()->is_loader_alive()) { 175 if (prev == NULL) { 176 // Try to clean head; this is contended by concurrent inserts, that 177 // both lazily clean the head, and insert entries at the head. If 178 // the CAS fails, the operation is restarted. 179 if (Atomic::cmpxchg(next, &_exception_cache, curr) != curr) { 180 prev = NULL; 181 curr = exception_cache_acquire(); 182 continue; 183 } 184 } else { 185 // It is impossible to during cleanup connect the next pointer to 186 // an ExceptionCache that has not been published before a safepoint 187 // prior to the cleanup. Therefore, release is not required. 188 prev->set_next(next); 189 } 190 // prev stays the same. 191 192 CodeCache::release_exception_cache(curr); 193 } else { 194 prev = curr; 195 } 196 197 curr = next; 198 } 199 } 200 201 // public method for accessing the exception cache 202 // These are the public access methods. 203 address CompiledMethod::handler_for_exception_and_pc(Handle exception, address pc) { 204 // We never grab a lock to read the exception cache, so we may 205 // have false negatives. This is okay, as it can only happen during 206 // the first few exception lookups for a given nmethod. 207 ExceptionCache* ec = exception_cache_acquire(); 208 while (ec != NULL) { 209 address ret_val; 210 if ((ret_val = ec->match(exception,pc)) != NULL) { 211 return ret_val; 212 } 213 ec = ec->next(); 214 } 215 return NULL; 216 } 217 218 void CompiledMethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) { 219 // There are potential race conditions during exception cache updates, so we 220 // must own the ExceptionCache_lock before doing ANY modifications. Because 221 // we don't lock during reads, it is possible to have several threads attempt 222 // to update the cache with the same data. We need to check for already inserted 223 // copies of the current data before adding it. 224 225 MutexLocker ml(ExceptionCache_lock); 226 ExceptionCache* target_entry = exception_cache_entry_for_exception(exception); 227 228 if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) { 229 target_entry = new ExceptionCache(exception,pc,handler); 230 add_exception_cache_entry(target_entry); 231 } 232 } 233 234 // private method for handling exception cache 235 // These methods are private, and used to manipulate the exception cache 236 // directly. 237 ExceptionCache* CompiledMethod::exception_cache_entry_for_exception(Handle exception) { 238 ExceptionCache* ec = exception_cache_acquire(); 239 while (ec != NULL) { 240 if (ec->match_exception_with_space(exception)) { 241 return ec; 242 } 243 ec = ec->next(); 244 } 245 return NULL; 246 } 247 248 //-------------end of code for ExceptionCache-------------- 249 250 bool CompiledMethod::is_at_poll_return(address pc) { 251 RelocIterator iter(this, pc, pc+1); 252 while (iter.next()) { 253 if (iter.type() == relocInfo::poll_return_type) 254 return true; 255 } 256 return false; 257 } 258 259 260 bool CompiledMethod::is_at_poll_or_poll_return(address pc) { 261 RelocIterator iter(this, pc, pc+1); 262 while (iter.next()) { 263 relocInfo::relocType t = iter.type(); 264 if (t == relocInfo::poll_return_type || t == relocInfo::poll_type) 265 return true; 266 } 267 return false; 268 } 269 270 void CompiledMethod::verify_oop_relocations() { 271 // Ensure sure that the code matches the current oop values 272 RelocIterator iter(this, NULL, NULL); 273 while (iter.next()) { 274 if (iter.type() == relocInfo::oop_type) { 275 oop_Relocation* reloc = iter.oop_reloc(); 276 if (!reloc->oop_is_immediate()) { 277 reloc->verify_oop_relocation(); 278 } 279 } 280 } 281 } 282 283 284 ScopeDesc* CompiledMethod::scope_desc_at(address pc) { 285 PcDesc* pd = pc_desc_at(pc); 286 guarantee(pd != NULL, "scope must be present"); 287 return new ScopeDesc(this, pd->scope_decode_offset(), 288 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(), 289 pd->return_oop()); 290 } 291 292 ScopeDesc* CompiledMethod::scope_desc_near(address pc) { 293 PcDesc* pd = pc_desc_near(pc); 294 guarantee(pd != NULL, "scope must be present"); 295 return new ScopeDesc(this, pd->scope_decode_offset(), 296 pd->obj_decode_offset(), pd->should_reexecute(), pd->rethrow_exception(), 297 pd->return_oop()); 298 } 299 300 address CompiledMethod::oops_reloc_begin() const { 301 // If the method is not entrant or zombie then a JMP is plastered over the 302 // first few bytes. If an oop in the old code was there, that oop 303 // should not get GC'd. Skip the first few bytes of oops on 304 // not-entrant methods. 305 if (frame_complete_offset() != CodeOffsets::frame_never_safe && 306 code_begin() + frame_complete_offset() > 307 verified_entry_point() + NativeJump::instruction_size) 308 { 309 // If we have a frame_complete_offset after the native jump, then there 310 // is no point trying to look for oops before that. This is a requirement 311 // for being allowed to scan oops concurrently. 312 return code_begin() + frame_complete_offset(); 313 } 314 315 // It is not safe to read oops concurrently using entry barriers, if their 316 // location depend on whether the nmethod is entrant or not. 317 assert(BarrierSet::barrier_set()->barrier_set_nmethod() == NULL, "Not safe oop scan"); 318 319 address low_boundary = verified_entry_point(); 320 if (!is_in_use() && is_nmethod()) { 321 low_boundary += NativeJump::instruction_size; 322 // %%% Note: On SPARC we patch only a 4-byte trap, not a full NativeJump. 323 // This means that the low_boundary is going to be a little too high. 324 // This shouldn't matter, since oops of non-entrant methods are never used. 325 // In fact, why are we bothering to look at oops in a non-entrant method?? 326 } 327 return low_boundary; 328 } 329 330 int CompiledMethod::verify_icholder_relocations() { 331 ResourceMark rm; 332 int count = 0; 333 334 RelocIterator iter(this); 335 while(iter.next()) { 336 if (iter.type() == relocInfo::virtual_call_type) { 337 if (CompiledIC::is_icholder_call_site(iter.virtual_call_reloc(), this)) { 338 CompiledIC *ic = CompiledIC_at(&iter); 339 if (TraceCompiledIC) { 340 tty->print("noticed icholder " INTPTR_FORMAT " ", p2i(ic->cached_icholder())); 341 ic->print(); 342 } 343 assert(ic->cached_icholder() != NULL, "must be non-NULL"); 344 count++; 345 } 346 } 347 } 348 349 return count; 350 } 351 352 // Method that knows how to preserve outgoing arguments at call. This method must be 353 // called with a frame corresponding to a Java invoke 354 void CompiledMethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) { 355 if (method() != NULL && !method()->is_native()) { 356 address pc = fr.pc(); 357 SimpleScopeDesc ssd(this, pc); 358 Bytecode_invoke call(methodHandle(Thread::current(), ssd.method()), ssd.bci()); 359 bool has_receiver = call.has_receiver(); 360 bool has_appendix = call.has_appendix(); 361 Symbol* signature = call.signature(); 362 363 // The method attached by JIT-compilers should be used, if present. 364 // Bytecode can be inaccurate in such case. 365 Method* callee = attached_method_before_pc(pc); 366 if (callee != NULL) { 367 has_receiver = !(callee->access_flags().is_static()); 368 has_appendix = false; 369 signature = callee->signature(); 370 } 371 372 fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f); 373 } 374 } 375 376 Method* CompiledMethod::attached_method(address call_instr) { 377 assert(code_contains(call_instr), "not part of the nmethod"); 378 RelocIterator iter(this, call_instr, call_instr + 1); 379 while (iter.next()) { 380 if (iter.addr() == call_instr) { 381 switch(iter.type()) { 382 case relocInfo::static_call_type: return iter.static_call_reloc()->method_value(); 383 case relocInfo::opt_virtual_call_type: return iter.opt_virtual_call_reloc()->method_value(); 384 case relocInfo::virtual_call_type: return iter.virtual_call_reloc()->method_value(); 385 default: break; 386 } 387 } 388 } 389 return NULL; // not found 390 } 391 392 Method* CompiledMethod::attached_method_before_pc(address pc) { 393 if (NativeCall::is_call_before(pc)) { 394 NativeCall* ncall = nativeCall_before(pc); 395 return attached_method(ncall->instruction_address()); 396 } 397 return NULL; // not a call 398 } 399 400 void CompiledMethod::clear_inline_caches() { 401 assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint"); 402 if (is_zombie()) { 403 return; 404 } 405 406 RelocIterator iter(this); 407 while (iter.next()) { 408 iter.reloc()->clear_inline_cache(); 409 } 410 } 411 412 // Clear IC callsites, releasing ICStubs of all compiled ICs 413 // as well as any associated CompiledICHolders. 414 void CompiledMethod::clear_ic_callsites() { 415 assert(CompiledICLocker::is_safe(this), "mt unsafe call"); 416 ResourceMark rm; 417 RelocIterator iter(this); 418 while(iter.next()) { 419 if (iter.type() == relocInfo::virtual_call_type) { 420 CompiledIC* ic = CompiledIC_at(&iter); 421 ic->set_to_clean(false); 422 } 423 } 424 } 425 426 #ifdef ASSERT 427 // Check class_loader is alive for this bit of metadata. 428 class CheckClass : public MetadataClosure { 429 void do_metadata(Metadata* md) { 430 Klass* klass = NULL; 431 if (md->is_klass()) { 432 klass = ((Klass*)md); 433 } else if (md->is_method()) { 434 klass = ((Method*)md)->method_holder(); 435 } else if (md->is_methodData()) { 436 klass = ((MethodData*)md)->method()->method_holder(); 437 } else { 438 md->print(); 439 ShouldNotReachHere(); 440 } 441 assert(klass->is_loader_alive(), "must be alive"); 442 } 443 }; 444 #endif // ASSERT 445 446 447 bool CompiledMethod::clean_ic_if_metadata_is_dead(CompiledIC *ic) { 448 if (ic->is_clean()) { 449 return true; 450 } 451 if (ic->is_icholder_call()) { 452 // The only exception is compiledICHolder metdata which may 453 // yet be marked below. (We check this further below). 454 CompiledICHolder* cichk_metdata = ic->cached_icholder(); 455 456 if (cichk_metdata->is_loader_alive()) { 457 return true; 458 } 459 } else { 460 Metadata* ic_metdata = ic->cached_metadata(); 461 if (ic_metdata != NULL) { 462 if (ic_metdata->is_klass()) { 463 if (((Klass*)ic_metdata)->is_loader_alive()) { 464 return true; 465 } 466 } else if (ic_metdata->is_method()) { 467 Method* method = (Method*)ic_metdata; 468 assert(!method->is_old(), "old method should have been cleaned"); 469 if (method->method_holder()->is_loader_alive()) { 470 return true; 471 } 472 } else { 473 ShouldNotReachHere(); 474 } 475 } 476 } 477 478 return ic->set_to_clean(); 479 } 480 481 // Clean references to unloaded nmethods at addr from this one, which is not unloaded. 482 template <class CompiledICorStaticCall> 483 static bool clean_if_nmethod_is_unloaded(CompiledICorStaticCall *ic, address addr, CompiledMethod* from, 484 bool clean_all) { 485 // Ok, to lookup references to zombies here 486 CodeBlob *cb = CodeCache::find_blob_unsafe(addr); 487 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL; 488 if (nm != NULL) { 489 // Clean inline caches pointing to both zombie and not_entrant methods 490 if (clean_all || !nm->is_in_use() || nm->is_unloading() || (nm->method()->code() != nm)) { 491 if (!ic->set_to_clean(from->is_alive())) { 492 return false; 493 } 494 assert(ic->is_clean(), "nmethod " PTR_FORMAT "not clean %s", p2i(from), from->method()->name_and_sig_as_C_string()); 495 } 496 } 497 return true; 498 } 499 500 static bool clean_if_nmethod_is_unloaded(CompiledIC *ic, CompiledMethod* from, 501 bool clean_all) { 502 return clean_if_nmethod_is_unloaded(ic, ic->ic_destination(), from, clean_all); 503 } 504 505 static bool clean_if_nmethod_is_unloaded(CompiledStaticCall *csc, CompiledMethod* from, 506 bool clean_all) { 507 return clean_if_nmethod_is_unloaded(csc, csc->destination(), from, clean_all); 508 } 509 510 // Cleans caches in nmethods that point to either classes that are unloaded 511 // or nmethods that are unloaded. 512 // 513 // Can be called either in parallel by G1 currently or after all 514 // nmethods are unloaded. Return postponed=true in the parallel case for 515 // inline caches found that point to nmethods that are not yet visited during 516 // the do_unloading walk. 517 bool CompiledMethod::unload_nmethod_caches(bool unloading_occurred) { 518 ResourceMark rm; 519 520 // Exception cache only needs to be called if unloading occurred 521 if (unloading_occurred) { 522 clean_exception_cache(); 523 } 524 525 if (!cleanup_inline_caches_impl(unloading_occurred, false)) { 526 return false; 527 } 528 529 #ifdef ASSERT 530 // Check that the metadata embedded in the nmethod is alive 531 CheckClass check_class; 532 metadata_do(&check_class); 533 #endif 534 return true; 535 } 536 537 void CompiledMethod::cleanup_inline_caches(bool clean_all) { 538 for (;;) { 539 ICRefillVerifier ic_refill_verifier; 540 { CompiledICLocker ic_locker(this); 541 if (cleanup_inline_caches_impl(false, clean_all)) { 542 return; 543 } 544 } 545 InlineCacheBuffer::refill_ic_stubs(); 546 } 547 } 548 549 // Called to clean up after class unloading for live nmethods and from the sweeper 550 // for all methods. 551 bool CompiledMethod::cleanup_inline_caches_impl(bool unloading_occurred, bool clean_all) { 552 assert(CompiledICLocker::is_safe(this), "mt unsafe call"); 553 ResourceMark rm; 554 555 // Find all calls in an nmethod and clear the ones that point to non-entrant, 556 // zombie and unloaded nmethods. 557 RelocIterator iter(this, oops_reloc_begin()); 558 bool is_in_static_stub = false; 559 while(iter.next()) { 560 561 switch (iter.type()) { 562 563 case relocInfo::virtual_call_type: 564 if (unloading_occurred) { 565 // If class unloading occurred we first clear ICs where the cached metadata 566 // is referring to an unloaded klass or method. 567 if (!clean_ic_if_metadata_is_dead(CompiledIC_at(&iter))) { 568 return false; 569 } 570 } 571 572 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) { 573 return false; 574 } 575 break; 576 577 case relocInfo::opt_virtual_call_type: 578 if (!clean_if_nmethod_is_unloaded(CompiledIC_at(&iter), this, clean_all)) { 579 return false; 580 } 581 break; 582 583 case relocInfo::static_call_type: 584 if (!clean_if_nmethod_is_unloaded(compiledStaticCall_at(iter.reloc()), this, clean_all)) { 585 return false; 586 } 587 break; 588 589 case relocInfo::static_stub_type: { 590 is_in_static_stub = true; 591 break; 592 } 593 594 case relocInfo::metadata_type: { 595 // Only the metadata relocations contained in static/opt virtual call stubs 596 // contains the Method* passed to c2i adapters. It is the only metadata 597 // relocation that needs to be walked, as it is the one metadata relocation 598 // that violates the invariant that all metadata relocations have an oop 599 // in the compiled method (due to deferred resolution and code patching). 600 601 // This causes dead metadata to remain in compiled methods that are not 602 // unloading. Unless these slippery metadata relocations of the static 603 // stubs are at least cleared, subsequent class redefinition operations 604 // will access potentially free memory, and JavaThread execution 605 // concurrent to class unloading may call c2i adapters with dead methods. 606 if (!is_in_static_stub) { 607 // The first metadata relocation after a static stub relocation is the 608 // metadata relocation of the static stub used to pass the Method* to 609 // c2i adapters. 610 continue; 611 } 612 is_in_static_stub = false; 613 metadata_Relocation* r = iter.metadata_reloc(); 614 Metadata* md = r->metadata_value(); 615 if (md != NULL && md->is_method()) { 616 Method* method = static_cast<Method*>(md); 617 if (!method->method_holder()->is_loader_alive()) { 618 Atomic::store((Method*)NULL, r->metadata_addr()); 619 620 if (!r->metadata_is_immediate()) { 621 r->fix_metadata_relocation(); 622 } 623 } 624 } 625 break; 626 } 627 628 default: 629 break; 630 } 631 } 632 633 return true; 634 } 635 636 // Iterating over all nmethods, e.g. with the help of CodeCache::nmethods_do(fun) was found 637 // to not be inherently safe. There is a chance that fields are seen which are not properly 638 // initialized. This happens despite the fact that nmethods_do() asserts the CodeCache_lock 639 // to be held. 640 // To bundle knowledge about necessary checks in one place, this function was introduced. 641 // It is not claimed that these checks are sufficient, but they were found to be necessary. 642 bool CompiledMethod::nmethod_access_is_safe(nmethod* nm) { 643 Method* method = (nm == NULL) ? NULL : nm->method(); // nm->method() may be uninitialized, i.e. != NULL, but invalid 644 return (nm != NULL) && (method != NULL) && (method->signature() != NULL) && 645 !nm->is_zombie() && !nm->is_not_installed() && 646 os::is_readable_pointer(method) && 647 os::is_readable_pointer(method->constants()) && 648 os::is_readable_pointer(method->signature()); 649 } 650 651 address CompiledMethod::continuation_for_implicit_exception(address pc, bool for_div0_check) { 652 // Exception happened outside inline-cache check code => we are inside 653 // an active nmethod => use cpc to determine a return address 654 int exception_offset = pc - code_begin(); 655 int cont_offset = ImplicitExceptionTable(this).continuation_offset( exception_offset ); 656 #ifdef ASSERT 657 if (cont_offset == 0) { 658 Thread* thread = Thread::current(); 659 ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY 660 HandleMark hm(thread); 661 ResourceMark rm(thread); 662 CodeBlob* cb = CodeCache::find_blob(pc); 663 assert(cb != NULL && cb == this, ""); 664 ttyLocker ttyl; 665 tty->print_cr("implicit exception happened at " INTPTR_FORMAT, p2i(pc)); 666 print(); 667 method()->print_codes(); 668 print_code(); 669 print_pcs(); 670 } 671 #endif 672 if (cont_offset == 0) { 673 // Let the normal error handling report the exception 674 return NULL; 675 } 676 if (cont_offset == exception_offset) { 677 #if INCLUDE_JVMCI 678 Deoptimization::DeoptReason deopt_reason = for_div0_check ? Deoptimization::Reason_div0_check : Deoptimization::Reason_null_check; 679 JavaThread *thread = JavaThread::current(); 680 thread->set_jvmci_implicit_exception_pc(pc); 681 thread->set_pending_deoptimization(Deoptimization::make_trap_request(deopt_reason, 682 Deoptimization::Action_reinterpret)); 683 return (SharedRuntime::deopt_blob()->implicit_exception_uncommon_trap()); 684 #else 685 ShouldNotReachHere(); 686 #endif 687 } 688 return code_begin() + cont_offset; 689 } 690 691 class HasEvolDependency : public MetadataClosure { 692 bool _has_evol_dependency; 693 public: 694 HasEvolDependency() : _has_evol_dependency(false) {} 695 void do_metadata(Metadata* md) { 696 if (md->is_method()) { 697 Method* method = (Method*)md; 698 if (method->is_old()) { 699 _has_evol_dependency = true; 700 } 701 } 702 } 703 bool has_evol_dependency() const { return _has_evol_dependency; } 704 }; 705 706 bool CompiledMethod::has_evol_metadata() { 707 // Check the metadata in relocIter and CompiledIC and also deoptimize 708 // any nmethod that has reference to old methods. 709 HasEvolDependency check_evol; 710 metadata_do(&check_evol); 711 if (check_evol.has_evol_dependency() && log_is_enabled(Debug, redefine, class, nmethod)) { 712 ResourceMark rm; 713 log_debug(redefine, class, nmethod) 714 ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on in nmethod metadata", 715 _method->method_holder()->external_name(), 716 _method->name()->as_C_string(), 717 _method->signature()->as_C_string(), 718 compile_id()); 719 } 720 return check_evol.has_evol_dependency(); 721 }