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