1 /* 2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 #include "precompiled.hpp" 27 #include "cds/dynamicArchive.hpp" 28 #include "ci/ciEnv.hpp" 29 #include "classfile/javaClasses.inline.hpp" 30 #include "classfile/javaThreadStatus.hpp" 31 #include "classfile/systemDictionary.hpp" 32 #include "classfile/vmClasses.hpp" 33 #include "classfile/vmSymbols.hpp" 34 #include "code/codeCache.hpp" 35 #include "code/scopeDesc.hpp" 36 #include "compiler/compileTask.hpp" 37 #include "compiler/compilerThread.hpp" 38 #include "gc/shared/oopStorage.hpp" 39 #include "gc/shared/oopStorageSet.hpp" 40 #include "gc/shared/tlab_globals.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "jvm.h" 43 #include "jvmtifiles/jvmtiEnv.hpp" 44 #include "logging/log.hpp" 45 #include "logging/logAsyncWriter.hpp" 46 #include "logging/logStream.hpp" 47 #include "memory/allocation.inline.hpp" 48 #include "memory/iterator.hpp" 49 #include "memory/universe.hpp" 50 #include "oops/access.inline.hpp" 51 #include "oops/instanceKlass.hpp" 52 #include "oops/klass.inline.hpp" 53 #include "oops/oop.inline.hpp" 54 #include "oops/oopHandle.inline.hpp" 55 #include "oops/verifyOopClosure.hpp" 56 #include "prims/jvm_misc.hpp" 57 #include "prims/jvmtiDeferredUpdates.hpp" 58 #include "prims/jvmtiExport.hpp" 59 #include "prims/jvmtiThreadState.inline.hpp" 60 #include "runtime/atomic.hpp" 61 #include "runtime/continuation.hpp" 62 #include "runtime/continuationEntry.inline.hpp" 63 #include "runtime/continuationHelper.inline.hpp" 64 #include "runtime/deoptimization.hpp" 65 #include "runtime/frame.inline.hpp" 66 #include "runtime/handles.inline.hpp" 67 #include "runtime/handshake.hpp" 68 #include "runtime/interfaceSupport.inline.hpp" 69 #include "runtime/java.hpp" 70 #include "runtime/javaCalls.hpp" 71 #include "runtime/javaThread.inline.hpp" 72 #include "runtime/jniHandles.inline.hpp" 73 #include "runtime/lockStack.inline.hpp" 74 #include "runtime/mutexLocker.hpp" 75 #include "runtime/orderAccess.hpp" 76 #include "runtime/os.inline.hpp" 77 #include "runtime/osThread.hpp" 78 #include "runtime/safepoint.hpp" 79 #include "runtime/safepointMechanism.inline.hpp" 80 #include "runtime/safepointVerifiers.hpp" 81 #include "runtime/serviceThread.hpp" 82 #include "runtime/stackFrameStream.inline.hpp" 83 #include "runtime/stackWatermarkSet.hpp" 84 #include "runtime/synchronizer.hpp" 85 #include "runtime/threadCritical.hpp" 86 #include "runtime/threadSMR.inline.hpp" 87 #include "runtime/threadStatisticalInfo.hpp" 88 #include "runtime/threadWXSetters.inline.hpp" 89 #include "runtime/timer.hpp" 90 #include "runtime/timerTrace.hpp" 91 #include "runtime/vframe.inline.hpp" 92 #include "runtime/vframeArray.hpp" 93 #include "runtime/vframe_hp.hpp" 94 #include "runtime/vmThread.hpp" 95 #include "runtime/vmOperations.hpp" 96 #include "services/threadService.hpp" 97 #include "utilities/copy.hpp" 98 #include "utilities/defaultStream.hpp" 99 #include "utilities/dtrace.hpp" 100 #include "utilities/events.hpp" 101 #include "utilities/macros.hpp" 102 #include "utilities/preserveException.hpp" 103 #include "utilities/spinYield.hpp" 104 #include "utilities/vmError.hpp" 105 #if INCLUDE_JVMCI 106 #include "jvmci/jvmci.hpp" 107 #include "jvmci/jvmciEnv.hpp" 108 #endif 109 #if INCLUDE_JFR 110 #include "jfr/jfr.hpp" 111 #endif 112 113 // Set by os layer. 114 size_t JavaThread::_stack_size_at_create = 0; 115 116 #ifdef DTRACE_ENABLED 117 118 // Only bother with this argument setup if dtrace is available 119 120 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 121 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 122 123 #define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->name(); \ 128 len = strlen(name); \ 129 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 130 (char *) name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (uintptr_t) (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136 #else // ndef DTRACE_ENABLED 137 138 #define DTRACE_THREAD_PROBE(probe, javathread) 139 140 #endif // ndef DTRACE_ENABLED 141 142 void JavaThread::smr_delete() { 143 if (_on_thread_list) { 144 ThreadsSMRSupport::smr_delete(this); 145 } else { 146 delete this; 147 } 148 } 149 150 // Initialized by VMThread at vm_global_init 151 OopStorage* JavaThread::_thread_oop_storage = nullptr; 152 153 OopStorage* JavaThread::thread_oop_storage() { 154 assert(_thread_oop_storage != nullptr, "not yet initialized"); 155 return _thread_oop_storage; 156 } 157 158 void JavaThread::set_threadOopHandles(oop p) { 159 assert(_thread_oop_storage != nullptr, "not yet initialized"); 160 _threadObj = OopHandle(_thread_oop_storage, p); 161 _vthread = OopHandle(_thread_oop_storage, p); 162 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr); 163 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr); 164 } 165 166 oop JavaThread::threadObj() const { 167 // Ideally we would verify the current thread is oop_safe when this is called, but as we can 168 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That 169 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS. 170 // Instead callers must verify oop safe access. 171 return _threadObj.resolve(); 172 } 173 174 oop JavaThread::vthread() const { 175 return _vthread.resolve(); 176 } 177 178 void JavaThread::set_vthread(oop p) { 179 assert(_thread_oop_storage != nullptr, "not yet initialized"); 180 _vthread.replace(p); 181 } 182 183 oop JavaThread::jvmti_vthread() const { 184 return _jvmti_vthread.resolve(); 185 } 186 187 void JavaThread::set_jvmti_vthread(oop p) { 188 assert(_thread_oop_storage != nullptr, "not yet initialized"); 189 _jvmti_vthread.replace(p); 190 } 191 192 // If there is a virtual thread mounted then return vthread() oop. 193 // Otherwise, return threadObj(). 194 oop JavaThread::vthread_or_thread() const { 195 oop result = vthread(); 196 if (result == nullptr) { 197 result = threadObj(); 198 } 199 return result; 200 } 201 202 oop JavaThread::scopedValueCache() const { 203 return _scopedValueCache.resolve(); 204 } 205 206 void JavaThread::set_scopedValueCache(oop p) { 207 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated 208 _scopedValueCache.replace(p); 209 } else { 210 assert(p == nullptr, "not yet initialized"); 211 } 212 } 213 214 void JavaThread::clear_scopedValueBindings() { 215 set_scopedValueCache(nullptr); 216 oop vthread_oop = vthread(); 217 // vthread may be null here if we get a VM error during startup, 218 // before the java.lang.Thread instance has been created. 219 if (vthread_oop != nullptr) { 220 java_lang_Thread::clear_scopedValueBindings(vthread_oop); 221 } 222 } 223 224 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 225 bool daemon, TRAPS) { 226 assert(thread_group.not_null(), "thread group should be specified"); 227 assert(threadObj() == nullptr, "should only create Java thread object once"); 228 229 InstanceKlass* ik = vmClasses::Thread_klass(); 230 assert(ik->is_initialized(), "must be"); 231 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 232 233 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon. 234 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread 235 // constructor calls Thread.current(), which must be set here. 236 java_lang_Thread::set_thread(thread_oop(), this); 237 set_threadOopHandles(thread_oop()); 238 239 JavaValue result(T_VOID); 240 if (thread_name != nullptr) { 241 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 242 // Thread gets assigned specified name and null target 243 JavaCalls::call_special(&result, 244 thread_oop, 245 ik, 246 vmSymbols::object_initializer_name(), 247 vmSymbols::threadgroup_string_void_signature(), 248 thread_group, 249 name, 250 CHECK); 251 } else { 252 // Thread gets assigned name "Thread-nnn" and null target 253 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 254 JavaCalls::call_special(&result, 255 thread_oop, 256 ik, 257 vmSymbols::object_initializer_name(), 258 vmSymbols::threadgroup_runnable_void_signature(), 259 thread_group, 260 Handle(), 261 CHECK); 262 } 263 os::set_priority(this, NormPriority); 264 265 if (daemon) { 266 java_lang_Thread::set_daemon(thread_oop()); 267 } 268 } 269 270 // ======= JavaThread ======== 271 272 #if INCLUDE_JVMCI 273 274 jlong* JavaThread::_jvmci_old_thread_counters; 275 276 static bool jvmci_counters_include(JavaThread* thread) { 277 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 278 } 279 280 void JavaThread::collect_counters(jlong* array, int length) { 281 assert(length == JVMCICounterSize, "wrong value"); 282 for (int i = 0; i < length; i++) { 283 array[i] = _jvmci_old_thread_counters[i]; 284 } 285 for (JavaThread* tp : ThreadsListHandle()) { 286 if (jvmci_counters_include(tp)) { 287 for (int i = 0; i < length; i++) { 288 array[i] += tp->_jvmci_counters[i]; 289 } 290 } 291 } 292 } 293 294 // Attempt to enlarge the array for per thread counters. 295 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) { 296 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI); 297 if (new_counters == nullptr) { 298 return nullptr; 299 } 300 if (old_counters == nullptr) { 301 old_counters = new_counters; 302 memset(old_counters, 0, sizeof(jlong) * new_size); 303 } else { 304 for (int i = 0; i < MIN2((int) current_size, new_size); i++) { 305 new_counters[i] = old_counters[i]; 306 } 307 if (new_size > current_size) { 308 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size)); 309 } 310 FREE_C_HEAP_ARRAY(jlong, old_counters); 311 } 312 return new_counters; 313 } 314 315 // Attempt to enlarge the array for per thread counters. 316 bool JavaThread::resize_counters(int current_size, int new_size) { 317 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size); 318 if (new_counters == nullptr) { 319 return false; 320 } else { 321 _jvmci_counters = new_counters; 322 return true; 323 } 324 } 325 326 class VM_JVMCIResizeCounters : public VM_Operation { 327 private: 328 int _new_size; 329 bool _failed; 330 331 public: 332 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { } 333 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; } 334 bool allow_nested_vm_operations() const { return true; } 335 void doit() { 336 // Resize the old thread counters array 337 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size); 338 if (new_counters == nullptr) { 339 _failed = true; 340 return; 341 } else { 342 JavaThread::_jvmci_old_thread_counters = new_counters; 343 } 344 345 // Now resize each threads array 346 for (JavaThread* tp : ThreadsListHandle()) { 347 if (!tp->resize_counters(JVMCICounterSize, _new_size)) { 348 _failed = true; 349 break; 350 } 351 } 352 if (!_failed) { 353 JVMCICounterSize = _new_size; 354 } 355 } 356 357 bool failed() { return _failed; } 358 }; 359 360 bool JavaThread::resize_all_jvmci_counters(int new_size) { 361 VM_JVMCIResizeCounters op(new_size); 362 VMThread::execute(&op); 363 return !op.failed(); 364 } 365 366 #endif // INCLUDE_JVMCI 367 368 #ifdef ASSERT 369 // Checks safepoint allowed and clears unhandled oops at potential safepoints. 370 void JavaThread::check_possible_safepoint() { 371 if (_no_safepoint_count > 0) { 372 print_owned_locks(); 373 assert(false, "Possible safepoint reached by thread that does not allow it"); 374 } 375 #ifdef CHECK_UNHANDLED_OOPS 376 // Clear unhandled oops in JavaThreads so we get a crash right away. 377 clear_unhandled_oops(); 378 #endif // CHECK_UNHANDLED_OOPS 379 380 // Macos/aarch64 should be in the right state for safepoint (e.g. 381 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely 382 // happens in practice, making such issues hard to find and reproduce. 383 #if defined(__APPLE__) && defined(AARCH64) 384 if (AssertWXAtThreadSync) { 385 assert_wx_state(WXWrite); 386 } 387 #endif 388 } 389 390 void JavaThread::check_for_valid_safepoint_state() { 391 // Don't complain if running a debugging command. 392 if (DebuggingContext::is_enabled()) return; 393 394 // Check NoSafepointVerifier, which is implied by locks taken that can be 395 // shared with the VM thread. This makes sure that no locks with allow_vm_block 396 // are held. 397 check_possible_safepoint(); 398 399 if (thread_state() != _thread_in_vm) { 400 fatal("LEAF method calling lock?"); 401 } 402 403 if (GCALotAtAllSafepoints) { 404 // We could enter a safepoint here and thus have a gc 405 InterfaceSupport::check_gc_alot(); 406 } 407 } 408 #endif // ASSERT 409 410 // A JavaThread is a normal Java thread 411 412 JavaThread::JavaThread() : 413 // Initialize fields 414 415 _on_thread_list(false), 416 DEBUG_ONLY(_java_call_counter(0) COMMA) 417 _entry_point(nullptr), 418 _deopt_mark(nullptr), 419 _deopt_nmethod(nullptr), 420 _vframe_array_head(nullptr), 421 _vframe_array_last(nullptr), 422 _jvmti_deferred_updates(nullptr), 423 _callee_target(nullptr), 424 _vm_result(nullptr), 425 _vm_result_2(nullptr), 426 427 _current_pending_monitor(nullptr), 428 _current_pending_monitor_is_from_java(true), 429 _current_waiting_monitor(nullptr), 430 _active_handles(nullptr), 431 _free_handle_block(nullptr), 432 433 _monitor_chunks(nullptr), 434 435 _suspend_flags(0), 436 437 _thread_state(_thread_new), 438 _saved_exception_pc(nullptr), 439 #ifdef ASSERT 440 _no_safepoint_count(0), 441 _visited_for_critical_count(false), 442 #endif 443 444 _terminated(_not_terminated), 445 _in_deopt_handler(0), 446 _doing_unsafe_access(false), 447 _do_not_unlock_if_synchronized(false), 448 #if INCLUDE_JVMTI 449 _carrier_thread_suspended(false), 450 _is_in_VTMS_transition(false), 451 _is_in_tmp_VTMS_transition(false), 452 _is_disable_suspend(false), 453 #ifdef ASSERT 454 _is_VTMS_transition_disabler(false), 455 #endif 456 #endif 457 _jni_attach_state(_not_attaching_via_jni), 458 #if INCLUDE_JVMCI 459 _pending_deoptimization(-1), 460 _pending_monitorenter(false), 461 _pending_transfer_to_interpreter(false), 462 _in_retryable_allocation(false), 463 _pending_failed_speculation(0), 464 _jvmci{nullptr}, 465 _libjvmci_runtime(nullptr), 466 _jvmci_counters(nullptr), 467 _jvmci_reserved0(0), 468 _jvmci_reserved1(0), 469 _jvmci_reserved_oop0(nullptr), 470 _live_nmethod(nullptr), 471 #endif // INCLUDE_JVMCI 472 473 _exception_oop(oop()), 474 _exception_pc(0), 475 _exception_handler_pc(0), 476 _is_method_handle_return(0), 477 478 _jni_active_critical(0), 479 _pending_jni_exception_check_fn(nullptr), 480 _depth_first_number(0), 481 482 // JVMTI PopFrame support 483 _popframe_condition(popframe_inactive), 484 _frames_to_pop_failed_realloc(0), 485 486 _cont_entry(nullptr), 487 _cont_fastpath(0), 488 _cont_fastpath_thread_state(1), 489 _held_monitor_count(0), 490 _jni_monitor_count(0), 491 492 _handshake(this), 493 494 _popframe_preserved_args(nullptr), 495 _popframe_preserved_args_size(0), 496 497 _jvmti_thread_state(nullptr), 498 _interp_only_mode(0), 499 _should_post_on_exceptions_flag(JNI_FALSE), 500 _thread_stat(new ThreadStatistics()), 501 502 _parker(), 503 504 _class_to_be_initialized(nullptr), 505 506 _SleepEvent(ParkEvent::Allocate(this)), 507 508 _lock_stack(this) { 509 set_jni_functions(jni_functions()); 510 511 #if INCLUDE_JVMCI 512 assert(_jvmci._implicit_exception_pc == nullptr, "must be"); 513 if (JVMCICounterSize > 0) { 514 resize_counters(0, (int) JVMCICounterSize); 515 } 516 #endif // INCLUDE_JVMCI 517 518 // Setup safepoint state info for this thread 519 ThreadSafepointState::create(this); 520 521 SafepointMechanism::initialize_header(this); 522 523 set_requires_cross_modify_fence(false); 524 525 pd_initialize(); 526 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 527 } 528 529 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() { 530 if (is_attaching_via_jni) { 531 _jni_attach_state = _attaching_via_jni; 532 } 533 } 534 535 536 // interrupt support 537 538 void JavaThread::interrupt() { 539 // All callers should have 'this' thread protected by a 540 // ThreadsListHandle so that it cannot terminate and deallocate 541 // itself. 542 debug_only(check_for_dangling_thread_pointer(this);) 543 544 // For Windows _interrupt_event 545 WINDOWS_ONLY(osthread()->set_interrupted(true);) 546 547 // For Thread.sleep 548 _SleepEvent->unpark(); 549 550 // For JSR166 LockSupport.park 551 parker()->unpark(); 552 553 // For ObjectMonitor and JvmtiRawMonitor 554 _ParkEvent->unpark(); 555 } 556 557 bool JavaThread::is_interrupted(bool clear_interrupted) { 558 debug_only(check_for_dangling_thread_pointer(this);) 559 560 if (_threadObj.peek() == nullptr) { 561 // If there is no j.l.Thread then it is impossible to have 562 // been interrupted. We can find null during VM initialization 563 // or when a JNI thread is still in the process of attaching. 564 // In such cases this must be the current thread. 565 assert(this == Thread::current(), "invariant"); 566 return false; 567 } 568 569 bool interrupted = java_lang_Thread::interrupted(threadObj()); 570 571 // NOTE that since there is no "lock" around the interrupt and 572 // is_interrupted operations, there is the possibility that the 573 // interrupted flag will be "false" but that the 574 // low-level events will be in the signaled state. This is 575 // intentional. The effect of this is that Object.wait() and 576 // LockSupport.park() will appear to have a spurious wakeup, which 577 // is allowed and not harmful, and the possibility is so rare that 578 // it is not worth the added complexity to add yet another lock. 579 // For the sleep event an explicit reset is performed on entry 580 // to JavaThread::sleep, so there is no early return. It has also been 581 // recommended not to put the interrupted flag into the "event" 582 // structure because it hides the issue. 583 // Also, because there is no lock, we must only clear the interrupt 584 // state if we are going to report that we were interrupted; otherwise 585 // an interrupt that happens just after we read the field would be lost. 586 if (interrupted && clear_interrupted) { 587 assert(this == Thread::current(), "only the current thread can clear"); 588 java_lang_Thread::set_interrupted(threadObj(), false); 589 WINDOWS_ONLY(osthread()->set_interrupted(false);) 590 } 591 return interrupted; 592 } 593 594 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of 595 // the Java code in Object::wait which are not present in RawMonitorWait. 596 bool JavaThread::get_and_clear_interrupted() { 597 if (!is_interrupted(false)) { 598 return false; 599 } 600 oop thread_oop = vthread_or_thread(); 601 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop); 602 603 if (!is_virtual) { 604 return is_interrupted(true); 605 } 606 // Virtual thread: clear interrupt status for both virtual and 607 // carrier threads under the interruptLock protection. 608 JavaThread* current = JavaThread::current(); 609 HandleMark hm(current); 610 Handle thread_h(current, thread_oop); 611 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current); 612 613 // re-check the interrupt status under the interruptLock protection 614 bool interrupted = java_lang_Thread::interrupted(thread_h()); 615 616 if (interrupted) { 617 assert(this == Thread::current(), "only the current thread can clear"); 618 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual 619 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier 620 WINDOWS_ONLY(osthread()->set_interrupted(false);) 621 } 622 return interrupted; 623 } 624 625 void JavaThread::block_if_vm_exited() { 626 if (_terminated == _vm_exited) { 627 // _vm_exited is set at safepoint, and Threads_lock is never released 628 // so we will block here forever. 629 // Here we can be doing a jump from a safe state to an unsafe state without 630 // proper transition, but it happens after the final safepoint has begun so 631 // this jump won't cause any safepoint problems. 632 set_thread_state(_thread_in_vm); 633 Threads_lock->lock(); 634 ShouldNotReachHere(); 635 } 636 } 637 638 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() { 639 _jni_attach_state = _not_attaching_via_jni; 640 set_entry_point(entry_point); 641 // Create the native thread itself. 642 // %note runtime_23 643 os::ThreadType thr_type = os::java_thread; 644 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread : 645 os::java_thread; 646 os::create_thread(this, thr_type, stack_sz); 647 // The _osthread may be null here because we ran out of memory (too many threads active). 648 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 649 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 650 // the exception consists of creating the exception object & initializing it, initialization 651 // will leave the VM via a JavaCall and then all locks must be unlocked). 652 // 653 // The thread is still suspended when we reach here. Thread must be explicit started 654 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 655 // by calling Threads:add. The reason why this is not done here, is because the thread 656 // object must be fully initialized (take a look at JVM_Start) 657 } 658 659 JavaThread::~JavaThread() { 660 661 // Enqueue OopHandles for release by the service thread. 662 add_oop_handles_for_release(); 663 664 // Return the sleep event to the free list 665 ParkEvent::Release(_SleepEvent); 666 _SleepEvent = nullptr; 667 668 // Free any remaining previous UnrollBlock 669 vframeArray* old_array = vframe_array_last(); 670 671 if (old_array != nullptr) { 672 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 673 old_array->set_unroll_block(nullptr); 674 delete old_info; 675 delete old_array; 676 } 677 678 JvmtiDeferredUpdates* updates = deferred_updates(); 679 if (updates != nullptr) { 680 // This can only happen if thread is destroyed before deoptimization occurs. 681 assert(updates->count() > 0, "Updates holder not deleted"); 682 // free deferred updates. 683 delete updates; 684 set_deferred_updates(nullptr); 685 } 686 687 // All Java related clean up happens in exit 688 ThreadSafepointState::destroy(this); 689 if (_thread_stat != nullptr) delete _thread_stat; 690 691 #if INCLUDE_JVMCI 692 if (JVMCICounterSize > 0) { 693 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 694 } 695 #endif // INCLUDE_JVMCI 696 } 697 698 699 // First JavaThread specific code executed by a new Java thread. 700 void JavaThread::pre_run() { 701 // empty - see comments in run() 702 } 703 704 // The main routine called by a new Java thread. This isn't overridden 705 // by subclasses, instead different subclasses define a different "entry_point" 706 // which defines the actual logic for that kind of thread. 707 void JavaThread::run() { 708 // initialize thread-local alloc buffer related fields 709 initialize_tlab(); 710 711 _stack_overflow_state.create_stack_guard_pages(); 712 713 cache_global_variables(); 714 715 // Thread is now sufficiently initialized to be handled by the safepoint code as being 716 // in the VM. Change thread state from _thread_new to _thread_in_vm 717 assert(this->thread_state() == _thread_new, "wrong thread state"); 718 set_thread_state(_thread_in_vm); 719 720 // Before a thread is on the threads list it is always safe, so after leaving the 721 // _thread_new we should emit a instruction barrier. The distance to modified code 722 // from here is probably far enough, but this is consistent and safe. 723 OrderAccess::cross_modify_fence(); 724 725 assert(JavaThread::current() == this, "sanity check"); 726 assert(!Thread::current()->owns_locks(), "sanity check"); 727 728 DTRACE_THREAD_PROBE(start, this); 729 730 // This operation might block. We call that after all safepoint checks for a new thread has 731 // been completed. 732 set_active_handles(JNIHandleBlock::allocate_block()); 733 734 if (JvmtiExport::should_post_thread_life()) { 735 JvmtiExport::post_thread_start(this); 736 737 } 738 739 if (AlwaysPreTouchStacks) { 740 pretouch_stack(); 741 } 742 743 // We call another function to do the rest so we are sure that the stack addresses used 744 // from there will be lower than the stack base just computed. 745 thread_main_inner(); 746 } 747 748 void JavaThread::thread_main_inner() { 749 assert(JavaThread::current() == this, "sanity check"); 750 assert(_threadObj.peek() != nullptr, "just checking"); 751 752 // Execute thread entry point unless this thread has a pending exception. 753 // Note: Due to JVMTI StopThread we can have pending exceptions already! 754 if (!this->has_pending_exception()) { 755 { 756 ResourceMark rm(this); 757 this->set_native_thread_name(this->name()); 758 } 759 HandleMark hm(this); 760 this->entry_point()(this, this); 761 } 762 763 DTRACE_THREAD_PROBE(stop, this); 764 765 // Cleanup is handled in post_run() 766 } 767 768 // Shared teardown for all JavaThreads 769 void JavaThread::post_run() { 770 this->exit(false); 771 this->unregister_thread_stack_with_NMT(); 772 // Defer deletion to here to ensure 'this' is still referenceable in call_run 773 // for any shared tear-down. 774 this->smr_delete(); 775 } 776 777 static void ensure_join(JavaThread* thread) { 778 // We do not need to grab the Threads_lock, since we are operating on ourself. 779 Handle threadObj(thread, thread->threadObj()); 780 assert(threadObj.not_null(), "java thread object must exist"); 781 ObjectLocker lock(threadObj, thread); 782 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 783 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED); 784 // Clear the native thread instance - this makes isAlive return false and allows the join() 785 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model 786 // requirements. 787 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive"); 788 java_lang_Thread::release_set_thread(threadObj(), nullptr); 789 lock.notify_all(thread); 790 // Ignore pending exception, since we are exiting anyway 791 thread->clear_pending_exception(); 792 } 793 794 static bool is_daemon(oop threadObj) { 795 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj)); 796 } 797 798 // For any new cleanup additions, please check to see if they need to be applied to 799 // cleanup_failed_attach_current_thread as well. 800 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 801 assert(this == JavaThread::current(), "thread consistency check"); 802 assert(!is_exiting(), "should not be exiting or terminated already"); 803 804 elapsedTimer _timer_exit_phase1; 805 elapsedTimer _timer_exit_phase2; 806 elapsedTimer _timer_exit_phase3; 807 elapsedTimer _timer_exit_phase4; 808 809 if (log_is_enabled(Debug, os, thread, timer)) { 810 _timer_exit_phase1.start(); 811 } 812 813 HandleMark hm(this); 814 Handle uncaught_exception(this, this->pending_exception()); 815 this->clear_pending_exception(); 816 Handle threadObj(this, this->threadObj()); 817 assert(threadObj.not_null(), "Java thread object should be created"); 818 819 if (!destroy_vm) { 820 if (uncaught_exception.not_null()) { 821 EXCEPTION_MARK; 822 // Call method Thread.dispatchUncaughtException(). 823 Klass* thread_klass = vmClasses::Thread_klass(); 824 JavaValue result(T_VOID); 825 JavaCalls::call_virtual(&result, 826 threadObj, thread_klass, 827 vmSymbols::dispatchUncaughtException_name(), 828 vmSymbols::throwable_void_signature(), 829 uncaught_exception, 830 THREAD); 831 if (HAS_PENDING_EXCEPTION) { 832 ResourceMark rm(this); 833 jio_fprintf(defaultStream::error_stream(), 834 "\nException: %s thrown from the UncaughtExceptionHandler" 835 " in thread \"%s\"\n", 836 pending_exception()->klass()->external_name(), 837 name()); 838 CLEAR_PENDING_EXCEPTION; 839 } 840 } 841 842 if (!is_Compiler_thread()) { 843 // We have finished executing user-defined Java code and now have to do the 844 // implementation specific clean-up by calling Thread.exit(). We prevent any 845 // asynchronous exceptions from being delivered while in Thread.exit() 846 // to ensure the clean-up is not corrupted. 847 NoAsyncExceptionDeliveryMark _no_async(this); 848 849 EXCEPTION_MARK; 850 JavaValue result(T_VOID); 851 Klass* thread_klass = vmClasses::Thread_klass(); 852 JavaCalls::call_virtual(&result, 853 threadObj, thread_klass, 854 vmSymbols::exit_method_name(), 855 vmSymbols::void_method_signature(), 856 THREAD); 857 CLEAR_PENDING_EXCEPTION; 858 } 859 860 // notify JVMTI 861 if (JvmtiExport::should_post_thread_life()) { 862 JvmtiExport::post_thread_end(this); 863 } 864 } else { 865 // before_exit() has already posted JVMTI THREAD_END events 866 } 867 868 // Cleanup any pending async exception now since we cannot access oops after 869 // BarrierSet::barrier_set()->on_thread_detach() has been executed. 870 if (has_async_exception_condition()) { 871 handshake_state()->clean_async_exception_operation(); 872 } 873 874 // The careful dance between thread suspension and exit is handled here. 875 // Since we are in thread_in_vm state and suspension is done with handshakes, 876 // we can just put in the exiting state and it will be correctly handled. 877 // Also, no more async exceptions will be added to the queue after this point. 878 set_terminated(_thread_exiting); 879 ThreadService::current_thread_exiting(this, is_daemon(threadObj())); 880 881 if (log_is_enabled(Debug, os, thread, timer)) { 882 _timer_exit_phase1.stop(); 883 _timer_exit_phase2.start(); 884 } 885 886 // Capture daemon status before the thread is marked as terminated. 887 bool daemon = is_daemon(threadObj()); 888 889 // Notify waiters on thread object. This has to be done after exit() is called 890 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 891 // group should have the destroyed bit set before waiters are notified). 892 ensure_join(this); 893 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 894 895 if (log_is_enabled(Debug, os, thread, timer)) { 896 _timer_exit_phase2.stop(); 897 _timer_exit_phase3.start(); 898 } 899 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 900 // held by this thread must be released. The spec does not distinguish 901 // between JNI-acquired and regular Java monitors. We can only see 902 // regular Java monitors here if monitor enter-exit matching is broken. 903 // 904 // ensure_join() ignores IllegalThreadStateExceptions, and so does 905 // ObjectSynchronizer::release_monitors_owned_by_thread(). 906 if (exit_type == jni_detach) { 907 // Sanity check even though JNI DetachCurrentThread() would have 908 // returned JNI_ERR if there was a Java frame. JavaThread exit 909 // should be done executing Java code by the time we get here. 910 assert(!this->has_last_Java_frame(), 911 "should not have a Java frame when detaching or exiting"); 912 ObjectSynchronizer::release_monitors_owned_by_thread(this); 913 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 914 // Check for monitor counts being out of sync. 915 assert(held_monitor_count() == jni_monitor_count(), 916 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT, 917 held_monitor_count(), jni_monitor_count()); 918 // All in-use monitors, including JNI-locked ones, should have been released above. 919 assert(held_monitor_count() == 0, "Failed to unlock " INTX_FORMAT " object monitors", 920 held_monitor_count()); 921 } else { 922 // Check for monitor counts being out of sync. 923 assert(held_monitor_count() == jni_monitor_count(), 924 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT, 925 held_monitor_count(), jni_monitor_count()); 926 // It is possible that a terminating thread failed to unlock monitors it locked 927 // via JNI so we don't assert the count is zero. 928 } 929 930 if (CheckJNICalls && jni_monitor_count() > 0) { 931 // We would like a fatal here, but due to we never checked this before there 932 // is a lot of tests which breaks, even with an error log. 933 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.", 934 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id()); 935 } 936 937 // These things needs to be done while we are still a Java Thread. Make sure that thread 938 // is in a consistent state, in case GC happens 939 JFR_ONLY(Jfr::on_thread_exit(this);) 940 941 if (active_handles() != nullptr) { 942 JNIHandleBlock* block = active_handles(); 943 set_active_handles(nullptr); 944 JNIHandleBlock::release_block(block); 945 } 946 947 if (free_handle_block() != nullptr) { 948 JNIHandleBlock* block = free_handle_block(); 949 set_free_handle_block(nullptr); 950 JNIHandleBlock::release_block(block); 951 } 952 953 // These have to be removed while this is still a valid thread. 954 _stack_overflow_state.remove_stack_guard_pages(); 955 956 if (UseTLAB) { 957 tlab().retire(); 958 } 959 960 if (JvmtiEnv::environments_might_exist()) { 961 JvmtiExport::cleanup_thread(this); 962 } 963 964 // We need to cache the thread name for logging purposes below as once 965 // we have called on_thread_detach this thread must not access any oops. 966 char* thread_name = nullptr; 967 if (log_is_enabled(Debug, os, thread, timer)) { 968 ResourceMark rm(this); 969 thread_name = os::strdup(name()); 970 } 971 972 if (log_is_enabled(Info, os, thread)) { 973 ResourceMark rm(this); 974 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: " UINTX_FORMAT ").", 975 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 976 name(), os::current_thread_id()); 977 } 978 979 if (log_is_enabled(Debug, os, thread, timer)) { 980 _timer_exit_phase3.stop(); 981 _timer_exit_phase4.start(); 982 } 983 984 #if INCLUDE_JVMCI 985 if (JVMCICounterSize > 0) { 986 if (jvmci_counters_include(this)) { 987 for (int i = 0; i < JVMCICounterSize; i++) { 988 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 989 } 990 } 991 } 992 #endif // INCLUDE_JVMCI 993 994 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread. 995 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point. 996 Threads::remove(this, daemon); 997 998 if (log_is_enabled(Debug, os, thread, timer)) { 999 _timer_exit_phase4.stop(); 1000 log_debug(os, thread, timer)("name='%s'" 1001 ", exit-phase1=" JLONG_FORMAT 1002 ", exit-phase2=" JLONG_FORMAT 1003 ", exit-phase3=" JLONG_FORMAT 1004 ", exit-phase4=" JLONG_FORMAT, 1005 thread_name, 1006 _timer_exit_phase1.milliseconds(), 1007 _timer_exit_phase2.milliseconds(), 1008 _timer_exit_phase3.milliseconds(), 1009 _timer_exit_phase4.milliseconds()); 1010 os::free(thread_name); 1011 } 1012 } 1013 1014 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) { 1015 if (active_handles() != nullptr) { 1016 JNIHandleBlock* block = active_handles(); 1017 set_active_handles(nullptr); 1018 JNIHandleBlock::release_block(block); 1019 } 1020 1021 if (free_handle_block() != nullptr) { 1022 JNIHandleBlock* block = free_handle_block(); 1023 set_free_handle_block(nullptr); 1024 JNIHandleBlock::release_block(block); 1025 } 1026 1027 // These have to be removed while this is still a valid thread. 1028 _stack_overflow_state.remove_stack_guard_pages(); 1029 1030 if (UseTLAB) { 1031 tlab().retire(); 1032 } 1033 1034 Threads::remove(this, is_daemon); 1035 this->smr_delete(); 1036 } 1037 1038 JavaThread* JavaThread::active() { 1039 Thread* thread = Thread::current(); 1040 if (thread->is_Java_thread()) { 1041 return JavaThread::cast(thread); 1042 } else { 1043 assert(thread->is_VM_thread(), "this must be a vm thread"); 1044 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1045 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread()); 1046 return ret; 1047 } 1048 } 1049 1050 bool JavaThread::is_lock_owned(address adr) const { 1051 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking"); 1052 if (Thread::is_lock_owned(adr)) return true; 1053 1054 for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) { 1055 if (chunk->contains(adr)) return true; 1056 } 1057 1058 return false; 1059 } 1060 1061 oop JavaThread::exception_oop() const { 1062 return Atomic::load(&_exception_oop); 1063 } 1064 1065 void JavaThread::set_exception_oop(oop o) { 1066 Atomic::store(&_exception_oop, o); 1067 } 1068 1069 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1070 chunk->set_next(monitor_chunks()); 1071 set_monitor_chunks(chunk); 1072 } 1073 1074 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1075 guarantee(monitor_chunks() != nullptr, "must be non empty"); 1076 if (monitor_chunks() == chunk) { 1077 set_monitor_chunks(chunk->next()); 1078 } else { 1079 MonitorChunk* prev = monitor_chunks(); 1080 while (prev->next() != chunk) prev = prev->next(); 1081 prev->set_next(chunk->next()); 1082 } 1083 } 1084 1085 void JavaThread::handle_special_runtime_exit_condition() { 1086 if (is_obj_deopt_suspend()) { 1087 frame_anchor()->make_walkable(); 1088 wait_for_object_deoptimization(); 1089 } 1090 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);) 1091 } 1092 1093 1094 // Asynchronous exceptions support 1095 // 1096 void JavaThread::handle_async_exception(oop java_throwable) { 1097 assert(java_throwable != nullptr, "should have an _async_exception to throw"); 1098 assert(!is_at_poll_safepoint(), "should have never called this method"); 1099 1100 if (has_last_Java_frame()) { 1101 frame f = last_frame(); 1102 if (f.is_runtime_frame()) { 1103 // If the topmost frame is a runtime stub, then we are calling into 1104 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 1105 // must deoptimize the caller before continuing, as the compiled exception 1106 // handler table may not be valid. 1107 RegisterMap reg_map(this, 1108 RegisterMap::UpdateMap::skip, 1109 RegisterMap::ProcessFrames::include, 1110 RegisterMap::WalkContinuation::skip); 1111 frame compiled_frame = f.sender(®_map); 1112 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 1113 Deoptimization::deoptimize(this, compiled_frame); 1114 } 1115 } 1116 } 1117 1118 // We cannot call Exceptions::_throw(...) here because we cannot block 1119 set_pending_exception(java_throwable, __FILE__, __LINE__); 1120 1121 clear_scopedValueBindings(); 1122 1123 LogTarget(Info, exceptions) lt; 1124 if (lt.is_enabled()) { 1125 ResourceMark rm; 1126 LogStream ls(lt); 1127 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 1128 if (has_last_Java_frame()) { 1129 frame f = last_frame(); 1130 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 1131 } 1132 ls.print_cr(" of type: %s", java_throwable->klass()->external_name()); 1133 } 1134 } 1135 1136 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) { 1137 // Do not throw asynchronous exceptions against the compiler thread 1138 // or if the thread is already exiting. 1139 if (!can_call_java() || is_exiting()) { 1140 delete aeh; 1141 return; 1142 } 1143 1144 oop exception = aeh->exception(); 1145 Handshake::execute(aeh, this); // Install asynchronous handshake 1146 1147 ResourceMark rm; 1148 if (log_is_enabled(Info, exceptions)) { 1149 log_info(exceptions)("Pending Async. exception installed of type: %s", 1150 InstanceKlass::cast(exception->klass())->external_name()); 1151 } 1152 // for AbortVMOnException flag 1153 Exceptions::debug_check_abort(exception->klass()->external_name()); 1154 1155 oop vt_oop = vthread(); 1156 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) { 1157 // Interrupt thread so it will wake up from a potential wait()/sleep()/park() 1158 java_lang_Thread::set_interrupted(threadObj(), true); 1159 this->interrupt(); 1160 } 1161 } 1162 1163 class InstallAsyncExceptionHandshake : public HandshakeClosure { 1164 AsyncExceptionHandshake* _aeh; 1165 public: 1166 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) : 1167 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {} 1168 ~InstallAsyncExceptionHandshake() { 1169 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh. 1170 delete _aeh; 1171 } 1172 void do_thread(Thread* thr) { 1173 JavaThread* target = JavaThread::cast(thr); 1174 target->install_async_exception(_aeh); 1175 _aeh = nullptr; 1176 } 1177 }; 1178 1179 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) { 1180 OopHandle e(Universe::vm_global(), java_throwable); 1181 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e)); 1182 Handshake::execute(&iaeh, target); 1183 } 1184 1185 #if INCLUDE_JVMTI 1186 void JavaThread::set_is_in_VTMS_transition(bool val) { 1187 _is_in_VTMS_transition = val; 1188 } 1189 1190 #ifdef ASSERT 1191 void JavaThread::set_is_VTMS_transition_disabler(bool val) { 1192 _is_VTMS_transition_disabler = val; 1193 } 1194 #endif 1195 #endif 1196 1197 // External suspension mechanism. 1198 // 1199 // Guarantees on return (for a valid target thread): 1200 // - Target thread will not execute any new bytecode. 1201 // - Target thread will not enter any new monitors. 1202 // 1203 bool JavaThread::java_suspend() { 1204 #if INCLUDE_JVMTI 1205 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks. 1206 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition"); 1207 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers"); 1208 #endif 1209 1210 guarantee(Thread::is_JavaThread_protected(/* target */ this), 1211 "target JavaThread is not protected in calling context."); 1212 return this->handshake_state()->suspend(); 1213 } 1214 1215 bool JavaThread::java_resume() { 1216 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this), 1217 "missing ThreadsListHandle in calling context."); 1218 return this->handshake_state()->resume(); 1219 } 1220 1221 // Wait for another thread to perform object reallocation and relocking on behalf of 1222 // this thread. The current thread is required to change to _thread_blocked in order 1223 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming 1224 // handshake safe, the other thread can complete the handshake used to synchronize 1225 // with this thread and then perform the reallocation and relocking. 1226 // See EscapeBarrier::sync_and_suspend_*() 1227 1228 void JavaThread::wait_for_object_deoptimization() { 1229 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack"); 1230 assert(this == Thread::current(), "invariant"); 1231 1232 bool spin_wait = os::is_MP(); 1233 do { 1234 ThreadBlockInVM tbivm(this, true /* allow_suspend */); 1235 // Wait for object deoptimization if requested. 1236 if (spin_wait) { 1237 // A single deoptimization is typically very short. Microbenchmarks 1238 // showed 5% better performance when spinning. 1239 const uint spin_limit = 10 * SpinYield::default_spin_limit; 1240 SpinYield spin(spin_limit); 1241 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) { 1242 spin.wait(); 1243 } 1244 // Spin just once 1245 spin_wait = false; 1246 } else { 1247 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag); 1248 if (is_obj_deopt_suspend()) { 1249 ml.wait(); 1250 } 1251 } 1252 // A handshake for obj. deoptimization suspend could have been processed so 1253 // we must check after processing. 1254 } while (is_obj_deopt_suspend()); 1255 } 1256 1257 #ifdef ASSERT 1258 // Verify the JavaThread has not yet been published in the Threads::list, and 1259 // hence doesn't need protection from concurrent access at this stage. 1260 void JavaThread::verify_not_published() { 1261 // Cannot create a ThreadsListHandle here and check !tlh.includes(this) 1262 // since an unpublished JavaThread doesn't participate in the 1263 // Thread-SMR protocol for keeping a ThreadsList alive. 1264 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!"); 1265 } 1266 #endif 1267 1268 // Slow path when the native==>Java barriers detect a safepoint/handshake is 1269 // pending, when _suspend_flags is non-zero or when we need to process a stack 1270 // watermark. Also check for pending async exceptions (except unsafe access error). 1271 // Note only the native==>Java barriers can call this function when thread state 1272 // is _thread_in_native_trans. 1273 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 1274 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 1275 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition"); 1276 1277 thread->set_thread_state(_thread_in_vm); 1278 1279 // Enable WXWrite: called directly from interpreter native wrapper. 1280 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread)); 1281 1282 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */); 1283 1284 // After returning from native, it could be that the stack frames are not 1285 // yet safe to use. We catch such situations in the subsequent stack watermark 1286 // barrier, which will trap unsafe stack frames. 1287 StackWatermarkSet::before_unwind(thread); 1288 } 1289 1290 #ifndef PRODUCT 1291 // Deoptimization 1292 // Function for testing deoptimization 1293 void JavaThread::deoptimize() { 1294 StackFrameStream fst(this, false /* update */, true /* process_frames */); 1295 bool deopt = false; // Dump stack only if a deopt actually happens. 1296 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 1297 // Iterate over all frames in the thread and deoptimize 1298 for (; !fst.is_done(); fst.next()) { 1299 if (fst.current()->can_be_deoptimized()) { 1300 1301 if (only_at) { 1302 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 1303 // consists of comma or carriage return separated numbers so 1304 // search for the current bci in that string. 1305 address pc = fst.current()->pc(); 1306 nmethod* nm = fst.current()->cb()->as_nmethod(); 1307 ScopeDesc* sd = nm->scope_desc_at(pc); 1308 char buffer[8]; 1309 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 1310 size_t len = strlen(buffer); 1311 const char * found = strstr(DeoptimizeOnlyAt, buffer); 1312 while (found != nullptr) { 1313 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 1314 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 1315 // Check that the bci found is bracketed by terminators. 1316 break; 1317 } 1318 found = strstr(found + 1, buffer); 1319 } 1320 if (!found) { 1321 continue; 1322 } 1323 } 1324 1325 if (DebugDeoptimization && !deopt) { 1326 deopt = true; // One-time only print before deopt 1327 tty->print_cr("[BEFORE Deoptimization]"); 1328 trace_frames(); 1329 trace_stack(); 1330 } 1331 Deoptimization::deoptimize(this, *fst.current()); 1332 } 1333 } 1334 1335 if (DebugDeoptimization && deopt) { 1336 tty->print_cr("[AFTER Deoptimization]"); 1337 trace_frames(); 1338 } 1339 } 1340 1341 1342 // Make zombies 1343 void JavaThread::make_zombies() { 1344 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) { 1345 if (fst.current()->can_be_deoptimized()) { 1346 // it is a Java nmethod 1347 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 1348 assert(nm != nullptr, "did not find nmethod"); 1349 nm->make_not_entrant(); 1350 } 1351 } 1352 } 1353 #endif // PRODUCT 1354 1355 1356 void JavaThread::deoptimize_marked_methods() { 1357 if (!has_last_Java_frame()) return; 1358 StackFrameStream fst(this, false /* update */, true /* process_frames */); 1359 for (; !fst.is_done(); fst.next()) { 1360 if (fst.current()->should_be_deoptimized()) { 1361 Deoptimization::deoptimize(this, *fst.current()); 1362 } 1363 } 1364 } 1365 1366 #ifdef ASSERT 1367 void JavaThread::verify_frame_info() { 1368 assert((!has_last_Java_frame() && java_call_counter() == 0) || 1369 (has_last_Java_frame() && java_call_counter() > 0), 1370 "unexpected frame info: has_last_frame=%s, java_call_counter=%d", 1371 has_last_Java_frame() ? "true" : "false", java_call_counter()); 1372 } 1373 #endif 1374 1375 // Push on a new block of JNI handles. 1376 void JavaThread::push_jni_handle_block() { 1377 // Allocate a new block for JNI handles. 1378 // Inlined code from jni_PushLocalFrame() 1379 JNIHandleBlock* old_handles = active_handles(); 1380 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this); 1381 assert(old_handles != nullptr && new_handles != nullptr, "should not be null"); 1382 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd. 1383 set_active_handles(new_handles); 1384 } 1385 1386 // Pop off the current block of JNI handles. 1387 void JavaThread::pop_jni_handle_block() { 1388 // Release our JNI handle block 1389 JNIHandleBlock* old_handles = active_handles(); 1390 JNIHandleBlock* new_handles = old_handles->pop_frame_link(); 1391 assert(new_handles != nullptr, "should never set active handles to null"); 1392 set_active_handles(new_handles); 1393 old_handles->set_pop_frame_link(nullptr); 1394 JNIHandleBlock::release_block(old_handles, this); 1395 } 1396 1397 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) { 1398 // Verify that the deferred card marks have been flushed. 1399 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 1400 1401 // Traverse the GCHandles 1402 Thread::oops_do_no_frames(f, cf); 1403 1404 if (active_handles() != nullptr) { 1405 active_handles()->oops_do(f); 1406 } 1407 1408 DEBUG_ONLY(verify_frame_info();) 1409 1410 if (has_last_Java_frame()) { 1411 // Traverse the monitor chunks 1412 for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) { 1413 chunk->oops_do(f); 1414 } 1415 } 1416 1417 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!"); 1418 // If we have deferred set_locals there might be oops waiting to be 1419 // written 1420 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this); 1421 if (list != nullptr) { 1422 for (int i = 0; i < list->length(); i++) { 1423 list->at(i)->oops_do(f); 1424 } 1425 } 1426 1427 // Traverse instance variables at the end since the GC may be moving things 1428 // around using this function 1429 f->do_oop((oop*) &_vm_result); 1430 f->do_oop((oop*) &_exception_oop); 1431 #if INCLUDE_JVMCI 1432 f->do_oop((oop*) &_jvmci_reserved_oop0); 1433 1434 if (_live_nmethod != nullptr && cf != nullptr) { 1435 cf->do_nmethod(_live_nmethod); 1436 } 1437 #endif 1438 1439 if (jvmti_thread_state() != nullptr) { 1440 jvmti_thread_state()->oops_do(f, cf); 1441 } 1442 1443 // The continuation oops are really on the stack. But there is typically at most 1444 // one of those per thread, so we handle them here in the oops_do_no_frames part 1445 // so that we don't have to sprinkle as many stack watermark checks where these 1446 // oops are used. We just need to make sure the thread has started processing. 1447 ContinuationEntry* entry = _cont_entry; 1448 while (entry != nullptr) { 1449 f->do_oop((oop*)entry->cont_addr()); 1450 f->do_oop((oop*)entry->chunk_addr()); 1451 entry = entry->parent(); 1452 } 1453 1454 if (LockingMode == LM_LIGHTWEIGHT) { 1455 lock_stack().oops_do(f); 1456 } 1457 } 1458 1459 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) { 1460 if (!has_last_Java_frame()) { 1461 return; 1462 } 1463 // Finish any pending lazy GC activity for the frames 1464 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc); 1465 // Traverse the execution stack 1466 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) { 1467 fst.current()->oops_do(f, cf, fst.register_map()); 1468 } 1469 } 1470 1471 #ifdef ASSERT 1472 void JavaThread::verify_states_for_handshake() { 1473 // This checks that the thread has a correct frame state during a handshake. 1474 verify_frame_info(); 1475 } 1476 #endif 1477 1478 void JavaThread::nmethods_do(NMethodClosure* cf) { 1479 DEBUG_ONLY(verify_frame_info();) 1480 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());) 1481 1482 if (has_last_Java_frame()) { 1483 // Traverse the execution stack 1484 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) { 1485 fst.current()->nmethod_do(cf); 1486 } 1487 } 1488 1489 if (jvmti_thread_state() != nullptr) { 1490 jvmti_thread_state()->nmethods_do(cf); 1491 } 1492 1493 #if INCLUDE_JVMCI 1494 if (_live_nmethod != nullptr) { 1495 cf->do_nmethod(_live_nmethod); 1496 } 1497 #endif 1498 } 1499 1500 void JavaThread::metadata_do(MetadataClosure* f) { 1501 if (has_last_Java_frame()) { 1502 // Traverse the execution stack to call f() on the methods in the stack 1503 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) { 1504 fst.current()->metadata_do(f); 1505 } 1506 } else if (is_Compiler_thread()) { 1507 // need to walk ciMetadata in current compile tasks to keep alive. 1508 CompilerThread* ct = (CompilerThread*)this; 1509 if (ct->env() != nullptr) { 1510 ct->env()->metadata_do(f); 1511 } 1512 CompileTask* task = ct->task(); 1513 if (task != nullptr) { 1514 task->metadata_do(f); 1515 } 1516 } 1517 } 1518 1519 // Printing 1520 static const char* _get_thread_state_name(JavaThreadState _thread_state) { 1521 switch (_thread_state) { 1522 case _thread_uninitialized: return "_thread_uninitialized"; 1523 case _thread_new: return "_thread_new"; 1524 case _thread_new_trans: return "_thread_new_trans"; 1525 case _thread_in_native: return "_thread_in_native"; 1526 case _thread_in_native_trans: return "_thread_in_native_trans"; 1527 case _thread_in_vm: return "_thread_in_vm"; 1528 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 1529 case _thread_in_Java: return "_thread_in_Java"; 1530 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 1531 case _thread_blocked: return "_thread_blocked"; 1532 case _thread_blocked_trans: return "_thread_blocked_trans"; 1533 default: return "unknown thread state"; 1534 } 1535 } 1536 1537 void JavaThread::print_thread_state_on(outputStream *st) const { 1538 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 1539 } 1540 1541 // Called by Threads::print() for VM_PrintThreads operation 1542 void JavaThread::print_on(outputStream *st, bool print_extended_info) const { 1543 st->print_raw("\""); 1544 st->print_raw(name()); 1545 st->print_raw("\" "); 1546 oop thread_oop = threadObj(); 1547 if (thread_oop != nullptr) { 1548 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id()); 1549 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 1550 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 1551 } 1552 Thread::print_on(st, print_extended_info); 1553 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 1554 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 1555 if (thread_oop != nullptr) { 1556 if (is_vthread_mounted()) { 1557 oop vt = vthread(); 1558 assert(vt != nullptr, ""); 1559 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt)); 1560 } else { 1561 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 1562 } 1563 } 1564 #ifndef PRODUCT 1565 _safepoint_state->print_on(st); 1566 #endif // PRODUCT 1567 if (is_Compiler_thread()) { 1568 CompileTask *task = ((CompilerThread*)this)->task(); 1569 if (task != nullptr) { 1570 st->print(" Compiling: "); 1571 task->print(st, nullptr, true, false); 1572 } else { 1573 st->print(" No compile task"); 1574 } 1575 st->cr(); 1576 } 1577 } 1578 1579 void JavaThread::print() const { print_on(tty); } 1580 1581 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 1582 st->print("%s", get_thread_name_string(buf, buflen)); 1583 } 1584 1585 // Called by fatal error handler. The difference between this and 1586 // JavaThread::print() is that we can't grab lock or allocate memory. 1587 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 1588 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen)); 1589 Thread* current = Thread::current_or_null_safe(); 1590 assert(current != nullptr, "cannot be called by a detached thread"); 1591 st->fill_to(60); 1592 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) { 1593 // Only access threadObj() if current thread is not a JavaThread 1594 // or if it is a JavaThread that can safely access oops. 1595 oop thread_obj = threadObj(); 1596 if (thread_obj != nullptr) { 1597 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " "); 1598 } 1599 } 1600 st->print(" ["); 1601 st->print("%s", _get_thread_state_name(_thread_state)); 1602 if (osthread()) { 1603 st->print(", id=%d", osthread()->thread_id()); 1604 } 1605 // Use raw field members for stack base/size as this could be 1606 // called before a thread has run enough to initialize them. 1607 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")", 1608 p2i(_stack_base - _stack_size), p2i(_stack_base), 1609 PROPERFMTARGS(_stack_size)); 1610 st->print("]"); 1611 1612 ThreadsSMRSupport::print_info_on(this, st); 1613 return; 1614 } 1615 1616 1617 // Verification 1618 1619 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 1620 // ignore if there is no stack 1621 if (!has_last_Java_frame()) return; 1622 // traverse the stack frames. Starts from top frame. 1623 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) { 1624 frame* fr = fst.current(); 1625 f(fr, fst.register_map()); 1626 } 1627 } 1628 1629 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 1630 1631 void JavaThread::verify() { 1632 // Verify oops in the thread. 1633 oops_do(&VerifyOopClosure::verify_oop, nullptr); 1634 1635 // Verify the stack frames. 1636 frames_do(frame_verify); 1637 } 1638 1639 // CR 6300358 (sub-CR 2137150) 1640 // Most callers of this method assume that it can't return null but a 1641 // thread may not have a name whilst it is in the process of attaching to 1642 // the VM - see CR 6412693, and there are places where a JavaThread can be 1643 // seen prior to having its threadObj set (e.g., JNI attaching threads and 1644 // if vm exit occurs during initialization). These cases can all be accounted 1645 // for such that this method never returns null. 1646 const char* JavaThread::name() const { 1647 if (Thread::is_JavaThread_protected(/* target */ this)) { 1648 // The target JavaThread is protected so get_thread_name_string() is safe: 1649 return get_thread_name_string(); 1650 } 1651 1652 // The target JavaThread is not protected so we return the default: 1653 return Thread::name(); 1654 } 1655 1656 // Like name() but doesn't include the protection check. This must only be 1657 // called when it is known to be safe, even though the protection check can't tell 1658 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp. 1659 const char* JavaThread::name_raw() const { 1660 return get_thread_name_string(); 1661 } 1662 1663 // Returns a non-null representation of this thread's name, or a suitable 1664 // descriptive string if there is no set name. 1665 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 1666 const char* name_str; 1667 #ifdef ASSERT 1668 Thread* current = Thread::current_or_null_safe(); 1669 assert(current != nullptr, "cannot be called by a detached thread"); 1670 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) { 1671 // Only access threadObj() if current thread is not a JavaThread 1672 // or if it is a JavaThread that can safely access oops. 1673 #endif 1674 oop thread_obj = threadObj(); 1675 if (thread_obj != nullptr) { 1676 oop name = java_lang_Thread::name(thread_obj); 1677 if (name != nullptr) { 1678 if (buf == nullptr) { 1679 name_str = java_lang_String::as_utf8_string(name); 1680 } else { 1681 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 1682 } 1683 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 1684 name_str = "<no-name - thread is attaching>"; 1685 } else { 1686 name_str = "<un-named>"; 1687 } 1688 } else { 1689 name_str = Thread::name(); 1690 } 1691 #ifdef ASSERT 1692 } else { 1693 // Current JavaThread has exited... 1694 if (current == this) { 1695 // ... and is asking about itself: 1696 name_str = "<no-name - current JavaThread has exited>"; 1697 } else { 1698 // ... and it can't safely determine this JavaThread's name so 1699 // use the default thread name. 1700 name_str = Thread::name(); 1701 } 1702 } 1703 #endif 1704 assert(name_str != nullptr, "unexpected null thread name"); 1705 return name_str; 1706 } 1707 1708 // Helper to extract the name from the thread oop for logging. 1709 const char* JavaThread::name_for(oop thread_obj) { 1710 assert(thread_obj != nullptr, "precondition"); 1711 oop name = java_lang_Thread::name(thread_obj); 1712 const char* name_str; 1713 if (name != nullptr) { 1714 name_str = java_lang_String::as_utf8_string(name); 1715 } else { 1716 name_str = "<un-named>"; 1717 } 1718 return name_str; 1719 } 1720 1721 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 1722 1723 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 1724 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check"); 1725 // Link Java Thread object <-> C++ Thread 1726 1727 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 1728 // and put it into a new Handle. The Handle "thread_oop" can then 1729 // be used to pass the C++ thread object to other methods. 1730 1731 // Set the Java level thread object (jthread) field of the 1732 // new thread (a JavaThread *) to C++ thread object using the 1733 // "thread_oop" handle. 1734 1735 // Set the thread field (a JavaThread *) of the 1736 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 1737 1738 Handle thread_oop(Thread::current(), 1739 JNIHandles::resolve_non_null(jni_thread)); 1740 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 1741 "must be initialized"); 1742 set_threadOopHandles(thread_oop()); 1743 1744 if (prio == NoPriority) { 1745 prio = java_lang_Thread::priority(thread_oop()); 1746 assert(prio != NoPriority, "A valid priority should be present"); 1747 } 1748 1749 // Push the Java priority down to the native thread; needs Threads_lock 1750 Thread::set_priority(this, prio); 1751 1752 // Add the new thread to the Threads list and set it in motion. 1753 // We must have threads lock in order to call Threads::add. 1754 // It is crucial that we do not block before the thread is 1755 // added to the Threads list for if a GC happens, then the java_thread oop 1756 // will not be visited by GC. 1757 Threads::add(this); 1758 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is 1759 // on a ThreadsList. We don't want to wait for the release when the 1760 // Theads_lock is dropped somewhere in the caller since the JavaThread* 1761 // is already visible to JVM/TI via the ThreadsList. 1762 java_lang_Thread::release_set_thread(thread_oop(), this); 1763 } 1764 1765 oop JavaThread::current_park_blocker() { 1766 // Support for JSR-166 locks 1767 oop thread_oop = threadObj(); 1768 if (thread_oop != nullptr) { 1769 return java_lang_Thread::park_blocker(thread_oop); 1770 } 1771 return nullptr; 1772 } 1773 1774 // Print current stack trace for checked JNI warnings and JNI fatal errors. 1775 // This is the external format, selecting the platform or vthread 1776 // as applicable, and allowing for a native-only stack. 1777 void JavaThread::print_jni_stack() { 1778 assert(this == JavaThread::current(), "Can't print stack of other threads"); 1779 if (!has_last_Java_frame()) { 1780 ResourceMark rm(this); 1781 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN); 1782 if (buf == nullptr) { 1783 tty->print_cr("Unable to print native stack - out of memory"); 1784 return; 1785 } 1786 address lastpc = nullptr; 1787 if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) { 1788 // We have printed the native stack in platform-specific code, 1789 // so nothing else to do in this case. 1790 } else { 1791 frame f = os::current_frame(); 1792 VMError::print_native_stack(tty, f, this, true /*print_source_info */, 1793 -1 /* max stack */, buf, O_BUFLEN); 1794 } 1795 } else { 1796 print_active_stack_on(tty); 1797 } 1798 } 1799 1800 void JavaThread::print_stack_on(outputStream* st) { 1801 if (!has_last_Java_frame()) return; 1802 1803 Thread* current_thread = Thread::current(); 1804 ResourceMark rm(current_thread); 1805 HandleMark hm(current_thread); 1806 1807 RegisterMap reg_map(this, 1808 RegisterMap::UpdateMap::include, 1809 RegisterMap::ProcessFrames::include, 1810 RegisterMap::WalkContinuation::skip); 1811 vframe* start_vf = platform_thread_last_java_vframe(®_map); 1812 int count = 0; 1813 for (vframe* f = start_vf; f != nullptr; f = f->sender()) { 1814 if (f->is_java_frame()) { 1815 javaVFrame* jvf = javaVFrame::cast(f); 1816 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 1817 1818 // Print out lock information 1819 if (JavaMonitorsInStackTrace) { 1820 jvf->print_lock_info_on(st, count); 1821 } 1822 } else { 1823 // Ignore non-Java frames 1824 } 1825 1826 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 1827 count++; 1828 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; 1829 } 1830 } 1831 1832 void JavaThread::print_vthread_stack_on(outputStream* st) { 1833 assert(is_vthread_mounted(), "Caller should have checked this"); 1834 assert(has_last_Java_frame(), "must be"); 1835 1836 Thread* current_thread = Thread::current(); 1837 ResourceMark rm(current_thread); 1838 HandleMark hm(current_thread); 1839 1840 RegisterMap reg_map(this, 1841 RegisterMap::UpdateMap::include, 1842 RegisterMap::ProcessFrames::include, 1843 RegisterMap::WalkContinuation::include); 1844 ContinuationEntry* cont_entry = last_continuation(); 1845 vframe* start_vf = last_java_vframe(®_map); 1846 int count = 0; 1847 for (vframe* f = start_vf; f != nullptr; f = f->sender()) { 1848 // Watch for end of vthread stack 1849 if (Continuation::is_continuation_enterSpecial(f->fr())) { 1850 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), ""); 1851 if (cont_entry->is_virtual_thread()) { 1852 break; 1853 } 1854 cont_entry = cont_entry->parent(); 1855 } 1856 if (f->is_java_frame()) { 1857 javaVFrame* jvf = javaVFrame::cast(f); 1858 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 1859 1860 // Print out lock information 1861 if (JavaMonitorsInStackTrace) { 1862 jvf->print_lock_info_on(st, count); 1863 } 1864 } else { 1865 // Ignore non-Java frames 1866 } 1867 1868 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 1869 count++; 1870 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; 1871 } 1872 } 1873 1874 void JavaThread::print_active_stack_on(outputStream* st) { 1875 if (is_vthread_mounted()) { 1876 print_vthread_stack_on(st); 1877 } else { 1878 print_stack_on(st); 1879 } 1880 } 1881 1882 #if INCLUDE_JVMTI 1883 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier. 1884 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) { 1885 set_jvmti_vthread(thread_oop); 1886 1887 // unbind current JvmtiThreadState from JavaThread 1888 JvmtiThreadState::unbind_from(jvmti_thread_state(), this); 1889 1890 // bind new JvmtiThreadState to JavaThread 1891 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this); 1892 1893 return jvmti_thread_state(); 1894 } 1895 #endif 1896 1897 // JVMTI PopFrame support 1898 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 1899 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments"); 1900 if (in_bytes(size_in_bytes) != 0) { 1901 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 1902 _popframe_preserved_args_size = in_bytes(size_in_bytes); 1903 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 1904 } 1905 } 1906 1907 void* JavaThread::popframe_preserved_args() { 1908 return _popframe_preserved_args; 1909 } 1910 1911 ByteSize JavaThread::popframe_preserved_args_size() { 1912 return in_ByteSize(_popframe_preserved_args_size); 1913 } 1914 1915 WordSize JavaThread::popframe_preserved_args_size_in_words() { 1916 int sz = in_bytes(popframe_preserved_args_size()); 1917 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 1918 return in_WordSize(sz / wordSize); 1919 } 1920 1921 void JavaThread::popframe_free_preserved_args() { 1922 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice"); 1923 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args); 1924 _popframe_preserved_args = nullptr; 1925 _popframe_preserved_args_size = 0; 1926 } 1927 1928 #ifndef PRODUCT 1929 1930 void JavaThread::trace_frames() { 1931 tty->print_cr("[Describe stack]"); 1932 int frame_no = 1; 1933 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) { 1934 tty->print(" %d. ", frame_no++); 1935 fst.current()->print_value_on(tty, this); 1936 tty->cr(); 1937 } 1938 } 1939 1940 class PrintAndVerifyOopClosure: public OopClosure { 1941 protected: 1942 template <class T> inline void do_oop_work(T* p) { 1943 oop obj = RawAccess<>::oop_load(p); 1944 if (obj == nullptr) return; 1945 tty->print(INTPTR_FORMAT ": ", p2i(p)); 1946 if (oopDesc::is_oop_or_null(obj)) { 1947 if (obj->is_objArray()) { 1948 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 1949 } else { 1950 obj->print(); 1951 } 1952 } else { 1953 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 1954 } 1955 tty->cr(); 1956 } 1957 public: 1958 virtual void do_oop(oop* p) { do_oop_work(p); } 1959 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 1960 }; 1961 1962 #ifdef ASSERT 1963 // Print or validate the layout of stack frames 1964 void JavaThread::print_frame_layout(int depth, bool validate_only) { 1965 ResourceMark rm; 1966 PreserveExceptionMark pm(this); 1967 FrameValues values; 1968 int frame_no = 0; 1969 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) { 1970 fst.current()->describe(values, ++frame_no, fst.register_map()); 1971 if (depth == frame_no) break; 1972 } 1973 Continuation::describe(values); 1974 if (validate_only) { 1975 values.validate(); 1976 } else { 1977 tty->print_cr("[Describe stack layout]"); 1978 values.print(this); 1979 } 1980 } 1981 #endif 1982 1983 void JavaThread::trace_stack_from(vframe* start_vf) { 1984 ResourceMark rm; 1985 int vframe_no = 1; 1986 for (vframe* f = start_vf; f; f = f->sender()) { 1987 if (f->is_java_frame()) { 1988 javaVFrame::cast(f)->print_activation(vframe_no++); 1989 } else { 1990 f->print(); 1991 } 1992 if (vframe_no > StackPrintLimit) { 1993 tty->print_cr("...<more frames>..."); 1994 return; 1995 } 1996 } 1997 } 1998 1999 2000 void JavaThread::trace_stack() { 2001 if (!has_last_Java_frame()) return; 2002 Thread* current_thread = Thread::current(); 2003 ResourceMark rm(current_thread); 2004 HandleMark hm(current_thread); 2005 RegisterMap reg_map(this, 2006 RegisterMap::UpdateMap::include, 2007 RegisterMap::ProcessFrames::include, 2008 RegisterMap::WalkContinuation::skip); 2009 trace_stack_from(last_java_vframe(®_map)); 2010 } 2011 2012 2013 #endif // PRODUCT 2014 2015 // Slow-path increment of the held monitor counts. JNI locking is always 2016 // this slow-path. 2017 void JavaThread::inc_held_monitor_count(intx i, bool jni) { 2018 #ifdef SUPPORT_MONITOR_COUNT 2019 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count); 2020 _held_monitor_count += i; 2021 if (jni) { 2022 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count); 2023 _jni_monitor_count += i; 2024 } 2025 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count " 2026 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count); 2027 #endif 2028 } 2029 2030 // Slow-path decrement of the held monitor counts. JNI unlocking is always 2031 // this slow-path. 2032 void JavaThread::dec_held_monitor_count(intx i, bool jni) { 2033 #ifdef SUPPORT_MONITOR_COUNT 2034 _held_monitor_count -= i; 2035 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count); 2036 if (jni) { 2037 _jni_monitor_count -= i; 2038 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count); 2039 } 2040 // When a thread is detaching with still owned JNI monitors, the logic that releases 2041 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync. 2042 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the 2043 // JNI count is directly set to zero. 2044 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count " 2045 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count); 2046 #endif 2047 } 2048 2049 frame JavaThread::vthread_last_frame() { 2050 assert (is_vthread_mounted(), "Virtual thread not mounted"); 2051 return last_frame(); 2052 } 2053 2054 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) { 2055 const ContinuationEntry* entry = vthread_continuation(); 2056 guarantee (entry != nullptr, "Not a carrier thread"); 2057 frame f = entry->to_frame(); 2058 if (reg_map->process_frames()) { 2059 entry->flush_stack_processing(this); 2060 } 2061 entry->update_register_map(reg_map); 2062 return f.sender(reg_map); 2063 } 2064 2065 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) { 2066 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame(); 2067 } 2068 2069 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) { 2070 assert(reg_map != nullptr, "a map must be given"); 2071 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 2072 if (vf->is_java_frame()) return javaVFrame::cast(vf); 2073 } 2074 return nullptr; 2075 } 2076 2077 Klass* JavaThread::security_get_caller_class(int depth) { 2078 ResetNoHandleMark rnhm; 2079 HandleMark hm(Thread::current()); 2080 2081 vframeStream vfst(this); 2082 vfst.security_get_caller_frame(depth); 2083 if (!vfst.at_end()) { 2084 return vfst.method()->method_holder(); 2085 } 2086 return nullptr; 2087 } 2088 2089 // Internal convenience function for millisecond resolution sleeps. 2090 bool JavaThread::sleep(jlong millis) { 2091 jlong nanos; 2092 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) { 2093 // Conversion to nanos would overflow, saturate at max 2094 nanos = max_jlong; 2095 } else { 2096 nanos = millis * NANOUNITS_PER_MILLIUNIT; 2097 } 2098 return sleep_nanos(nanos); 2099 } 2100 2101 // java.lang.Thread.sleep support 2102 // Returns true if sleep time elapsed as expected, and false 2103 // if the thread was interrupted. 2104 bool JavaThread::sleep_nanos(jlong nanos) { 2105 assert(this == Thread::current(), "thread consistency check"); 2106 assert(nanos >= 0, "nanos are in range"); 2107 2108 ParkEvent * const slp = this->_SleepEvent; 2109 // Because there can be races with thread interruption sending an unpark() 2110 // to the event, we explicitly reset it here to avoid an immediate return. 2111 // The actual interrupt state will be checked before we park(). 2112 slp->reset(); 2113 // Thread interruption establishes a happens-before ordering in the 2114 // Java Memory Model, so we need to ensure we synchronize with the 2115 // interrupt state. 2116 OrderAccess::fence(); 2117 2118 jlong prevtime = os::javaTimeNanos(); 2119 2120 jlong nanos_remaining = nanos; 2121 2122 for (;;) { 2123 // interruption has precedence over timing out 2124 if (this->is_interrupted(true)) { 2125 return false; 2126 } 2127 2128 if (nanos_remaining <= 0) { 2129 return true; 2130 } 2131 2132 { 2133 ThreadBlockInVM tbivm(this); 2134 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 2135 slp->park_nanos(nanos_remaining); 2136 } 2137 2138 // Update elapsed time tracking 2139 jlong newtime = os::javaTimeNanos(); 2140 if (newtime - prevtime < 0) { 2141 // time moving backwards, should only happen if no monotonic clock 2142 // not a guarantee() because JVM should not abort on kernel/glibc bugs 2143 assert(false, 2144 "unexpected time moving backwards detected in JavaThread::sleep()"); 2145 } else { 2146 nanos_remaining -= (newtime - prevtime); 2147 } 2148 prevtime = newtime; 2149 } 2150 } 2151 2152 // Last thread running calls java.lang.Shutdown.shutdown() 2153 void JavaThread::invoke_shutdown_hooks() { 2154 HandleMark hm(this); 2155 2156 // We could get here with a pending exception, if so clear it now. 2157 if (this->has_pending_exception()) { 2158 this->clear_pending_exception(); 2159 } 2160 2161 EXCEPTION_MARK; 2162 Klass* shutdown_klass = 2163 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 2164 THREAD); 2165 if (shutdown_klass != nullptr) { 2166 // SystemDictionary::resolve_or_null will return null if there was 2167 // an exception. If we cannot load the Shutdown class, just don't 2168 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 2169 // won't be run. Note that if a shutdown hook was registered, 2170 // the Shutdown class would have already been loaded 2171 // (Runtime.addShutdownHook will load it). 2172 JavaValue result(T_VOID); 2173 JavaCalls::call_static(&result, 2174 shutdown_klass, 2175 vmSymbols::shutdown_name(), 2176 vmSymbols::void_method_signature(), 2177 THREAD); 2178 } 2179 CLEAR_PENDING_EXCEPTION; 2180 } 2181 2182 #ifndef PRODUCT 2183 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) { 2184 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread); 2185 } 2186 #endif 2187 2188 // Helper function to create the java.lang.Thread object for a 2189 // VM-internal thread. The thread will have the given name, and be 2190 // a member of the "system" ThreadGroup. 2191 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) { 2192 Handle string = java_lang_String::create_from_str(name, CHECK_NH); 2193 2194 // Initialize thread_oop to put it into the system threadGroup. 2195 // This is done by calling the Thread(ThreadGroup group, String name) constructor. 2196 Handle thread_group(THREAD, Universe::system_thread_group()); 2197 Handle thread_oop = 2198 JavaCalls::construct_new_instance(vmClasses::Thread_klass(), 2199 vmSymbols::threadgroup_string_void_signature(), 2200 thread_group, 2201 string, 2202 CHECK_NH); 2203 2204 return thread_oop; 2205 } 2206 2207 // Starts the target JavaThread as a daemon of the given priority, and 2208 // bound to the given java.lang.Thread instance. 2209 // The Threads_lock is held for the duration. 2210 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target, 2211 Handle thread_oop, ThreadPriority prio) { 2212 2213 assert(target->osthread() != nullptr, "target thread is not properly initialized"); 2214 2215 MutexLocker mu(current, Threads_lock); 2216 2217 // Initialize the fields of the thread_oop first. 2218 if (prio != NoPriority) { 2219 java_lang_Thread::set_priority(thread_oop(), prio); 2220 // Note: we don't call os::set_priority here. Possibly we should, 2221 // else all threads should call it themselves when they first run. 2222 } 2223 2224 java_lang_Thread::set_daemon(thread_oop()); 2225 2226 // Now bind the thread_oop to the target JavaThread. 2227 target->set_threadOopHandles(thread_oop()); 2228 2229 Threads::add(target); // target is now visible for safepoint/handshake 2230 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is 2231 // on a ThreadsList. We don't want to wait for the release when the 2232 // Theads_lock is dropped when the 'mu' destructor is run since the 2233 // JavaThread* is already visible to JVM/TI via the ThreadsList. 2234 2235 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive"); 2236 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now 2237 Thread::start(target); 2238 } 2239 2240 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) { 2241 // At this point it may be possible that no osthread was created for the 2242 // JavaThread due to lack of resources. However, since this must work 2243 // for critical system threads just check and abort if this fails. 2244 if (thread->osthread() == nullptr) { 2245 // This isn't really an OOM condition, but historically this is what 2246 // we report. 2247 vm_exit_during_initialization("java.lang.OutOfMemoryError", 2248 os::native_thread_creation_failed_msg()); 2249 } 2250 } 2251 2252 void JavaThread::pretouch_stack() { 2253 // Given an established java thread stack with usable area followed by 2254 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging 2255 // from the current frame down to the start of the shadow zone. 2256 const address end = _stack_overflow_state.shadow_zone_safe_limit(); 2257 if (is_in_full_stack(end)) { 2258 char* p1 = (char*) alloca(1); 2259 address here = (address) &p1; 2260 if (is_in_full_stack(here) && here > end) { 2261 size_t to_alloc = here - end; 2262 char* p2 = (char*) alloca(to_alloc); 2263 log_trace(os, thread)("Pretouching thread stack from " PTR_FORMAT " to " PTR_FORMAT ".", 2264 p2i(p2), p2i(end)); 2265 os::pretouch_memory(p2, p2 + to_alloc, 2266 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096)); 2267 } 2268 } 2269 } 2270 2271 // Deferred OopHandle release support. 2272 2273 class OopHandleList : public CHeapObj<mtInternal> { 2274 static const int _count = 4; 2275 OopHandle _handles[_count]; 2276 OopHandleList* _next; 2277 int _index; 2278 public: 2279 OopHandleList(OopHandleList* next) : _next(next), _index(0) {} 2280 void add(OopHandle h) { 2281 assert(_index < _count, "too many additions"); 2282 _handles[_index++] = h; 2283 } 2284 ~OopHandleList() { 2285 assert(_index == _count, "usage error"); 2286 for (int i = 0; i < _index; i++) { 2287 _handles[i].release(JavaThread::thread_oop_storage()); 2288 } 2289 } 2290 OopHandleList* next() const { return _next; } 2291 }; 2292 2293 OopHandleList* JavaThread::_oop_handle_list = nullptr; 2294 2295 // Called by the ServiceThread to do the work of releasing 2296 // the OopHandles. 2297 void JavaThread::release_oop_handles() { 2298 OopHandleList* list; 2299 { 2300 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag); 2301 list = _oop_handle_list; 2302 _oop_handle_list = nullptr; 2303 } 2304 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint"); 2305 2306 while (list != nullptr) { 2307 OopHandleList* l = list; 2308 list = l->next(); 2309 delete l; 2310 } 2311 } 2312 2313 // Add our OopHandles for later release. 2314 void JavaThread::add_oop_handles_for_release() { 2315 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag); 2316 OopHandleList* new_head = new OopHandleList(_oop_handle_list); 2317 new_head->add(_threadObj); 2318 new_head->add(_vthread); 2319 new_head->add(_jvmti_vthread); 2320 new_head->add(_scopedValueCache); 2321 _oop_handle_list = new_head; 2322 Service_lock->notify_all(); 2323 }