1 /*
   2  * Copyright (c) 1997, 2025, 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 "cds/dynamicArchive.hpp"
  27 #include "ci/ciEnv.hpp"
  28 #include "classfile/javaClasses.inline.hpp"
  29 #include "classfile/javaThreadStatus.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmClasses.hpp"
  32 #include "classfile/vmSymbols.hpp"
  33 #include "code/codeCache.hpp"
  34 #include "code/scopeDesc.hpp"
  35 #include "compiler/compileTask.hpp"
  36 #include "compiler/compilerThread.hpp"
  37 #include "gc/shared/oopStorage.hpp"
  38 #include "gc/shared/oopStorageSet.hpp"
  39 #include "gc/shared/tlab_globals.hpp"
  40 #include "jfr/jfrEvents.hpp"
  41 #include "jvm.h"
  42 #include "jvmtifiles/jvmtiEnv.hpp"
  43 #include "logging/log.hpp"
  44 #include "logging/logAsyncWriter.hpp"
  45 #include "logging/logStream.hpp"
  46 #include "memory/allocation.inline.hpp"
  47 #include "memory/iterator.hpp"
  48 #include "memory/universe.hpp"
  49 #include "oops/access.inline.hpp"
  50 #include "oops/instanceKlass.hpp"
  51 #include "oops/klass.inline.hpp"
  52 #include "oops/oop.inline.hpp"
  53 #include "oops/oopHandle.inline.hpp"
  54 #include "oops/verifyOopClosure.hpp"
  55 #include "prims/jvm_misc.hpp"
  56 #include "prims/jvmtiDeferredUpdates.hpp"
  57 #include "prims/jvmtiExport.hpp"
  58 #include "prims/jvmtiThreadState.inline.hpp"
  59 #include "runtime/atomic.hpp"
  60 #include "runtime/continuation.hpp"
  61 #include "runtime/continuationEntry.inline.hpp"
  62 #include "runtime/continuationHelper.inline.hpp"
  63 #include "runtime/deoptimization.hpp"
  64 #include "runtime/frame.inline.hpp"
  65 #include "runtime/handles.inline.hpp"
  66 #include "runtime/handshake.hpp"
  67 #include "runtime/interfaceSupport.inline.hpp"
  68 #include "runtime/java.hpp"
  69 #include "runtime/javaCalls.hpp"
  70 #include "runtime/javaThread.inline.hpp"
  71 #include "runtime/jniHandles.inline.hpp"
  72 #include "runtime/lockStack.inline.hpp"
  73 #include "runtime/mutexLocker.hpp"
  74 #include "runtime/orderAccess.hpp"
  75 #include "runtime/os.inline.hpp"
  76 #include "runtime/osThread.hpp"
  77 #include "runtime/safepoint.hpp"
  78 #include "runtime/safepointMechanism.inline.hpp"
  79 #include "runtime/safepointVerifiers.hpp"
  80 #include "runtime/serviceThread.hpp"
  81 #include "runtime/stackFrameStream.inline.hpp"
  82 #include "runtime/stackWatermarkSet.hpp"
  83 #include "runtime/synchronizer.hpp"
  84 #include "runtime/threadIdentifier.hpp"
  85 #include "runtime/threadSMR.inline.hpp"
  86 #include "runtime/threadStatisticalInfo.hpp"
  87 #include "runtime/threadWXSetters.inline.hpp"
  88 #include "runtime/timer.hpp"
  89 #include "runtime/timerTrace.hpp"
  90 #include "runtime/vframe.inline.hpp"
  91 #include "runtime/vframeArray.hpp"
  92 #include "runtime/vframe_hp.hpp"
  93 #include "runtime/vmThread.hpp"
  94 #include "runtime/vmOperations.hpp"
  95 #include "services/threadService.hpp"
  96 #include "utilities/copy.hpp"
  97 #include "utilities/defaultStream.hpp"
  98 #include "utilities/dtrace.hpp"
  99 #include "utilities/events.hpp"
 100 #include "utilities/macros.hpp"
 101 #include "utilities/nativeStackPrinter.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 
 264   os::set_priority(this, NormPriority);
 265 
 266   if (daemon) {
 267     java_lang_Thread::set_daemon(thread_oop());
 268   }
 269 }
 270 
 271 // ======= JavaThread ========
 272 
 273 #if INCLUDE_JVMCI
 274 
 275 jlong* JavaThread::_jvmci_old_thread_counters;
 276 
 277 static bool jvmci_counters_include(JavaThread* thread) {
 278   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 279 }
 280 
 281 void JavaThread::collect_counters(jlong* array, int length) {
 282   assert(length == JVMCICounterSize, "wrong value");
 283   for (int i = 0; i < length; i++) {
 284     array[i] = _jvmci_old_thread_counters[i];
 285   }
 286   for (JavaThread* tp : ThreadsListHandle()) {
 287     if (jvmci_counters_include(tp)) {
 288       for (int i = 0; i < length; i++) {
 289         array[i] += tp->_jvmci_counters[i];
 290       }
 291     }
 292   }
 293 }
 294 
 295 // Attempt to enlarge the array for per thread counters.
 296 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 297   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 298   if (new_counters == nullptr) {
 299     return nullptr;
 300   }
 301   if (old_counters == nullptr) {
 302     old_counters = new_counters;
 303     memset(old_counters, 0, sizeof(jlong) * new_size);
 304   } else {
 305     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 306       new_counters[i] = old_counters[i];
 307     }
 308     if (new_size > current_size) {
 309       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 310     }
 311     FREE_C_HEAP_ARRAY(jlong, old_counters);
 312   }
 313   return new_counters;
 314 }
 315 
 316 // Attempt to enlarge the array for per thread counters.
 317 bool JavaThread::resize_counters(int current_size, int new_size) {
 318   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 319   if (new_counters == nullptr) {
 320     return false;
 321   } else {
 322     _jvmci_counters = new_counters;
 323     return true;
 324   }
 325 }
 326 
 327 class VM_JVMCIResizeCounters : public VM_Operation {
 328  private:
 329   int _new_size;
 330   bool _failed;
 331 
 332  public:
 333   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 334   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 335   bool allow_nested_vm_operations() const        { return true; }
 336   void doit() {
 337     // Resize the old thread counters array
 338     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 339     if (new_counters == nullptr) {
 340       _failed = true;
 341       return;
 342     } else {
 343       JavaThread::_jvmci_old_thread_counters = new_counters;
 344     }
 345 
 346     // Now resize each threads array
 347     for (JavaThread* tp : ThreadsListHandle()) {
 348       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 349         _failed = true;
 350         break;
 351       }
 352     }
 353     if (!_failed) {
 354       JVMCICounterSize = _new_size;
 355     }
 356   }
 357 
 358   bool failed() { return _failed; }
 359 };
 360 
 361 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 362   VM_JVMCIResizeCounters op(new_size);
 363   VMThread::execute(&op);
 364   return !op.failed();
 365 }
 366 
 367 #endif // INCLUDE_JVMCI
 368 
 369 #ifdef ASSERT
 370 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 371 void JavaThread::check_possible_safepoint() {
 372   if (_no_safepoint_count > 0) {
 373     print_owned_locks();
 374     assert(false, "Possible safepoint reached by thread that does not allow it");
 375   }
 376 #ifdef CHECK_UNHANDLED_OOPS
 377   // Clear unhandled oops in JavaThreads so we get a crash right away.
 378   clear_unhandled_oops();
 379 #endif // CHECK_UNHANDLED_OOPS
 380 
 381   // Macos/aarch64 should be in the right state for safepoint (e.g.
 382   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 383   // happens in practice, making such issues hard to find and reproduce.
 384 #if defined(__APPLE__) && defined(AARCH64)
 385   if (AssertWXAtThreadSync) {
 386     assert_wx_state(WXWrite);
 387   }
 388 #endif
 389 }
 390 
 391 void JavaThread::check_for_valid_safepoint_state() {
 392   // Don't complain if running a debugging command.
 393   if (DebuggingContext::is_enabled()) return;
 394 
 395   // Check NoSafepointVerifier, which is implied by locks taken that can be
 396   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 397   // are held.
 398   check_possible_safepoint();
 399 
 400   if (thread_state() != _thread_in_vm) {
 401     fatal("LEAF method calling lock?");
 402   }
 403 
 404   if (GCALotAtAllSafepoints) {
 405     // We could enter a safepoint here and thus have a gc
 406     InterfaceSupport::check_gc_alot();
 407   }
 408 }
 409 #endif // ASSERT
 410 
 411 // A JavaThread is a normal Java thread
 412 
 413 JavaThread::JavaThread(MemTag mem_tag) :
 414   Thread(mem_tag),
 415   // Initialize fields
 416   _on_thread_list(false),
 417   DEBUG_ONLY(_java_call_counter(0) COMMA)
 418   _entry_point(nullptr),
 419   _deopt_mark(nullptr),
 420   _deopt_nmethod(nullptr),
 421   _vframe_array_head(nullptr),
 422   _vframe_array_last(nullptr),
 423   _jvmti_deferred_updates(nullptr),
 424   _callee_target(nullptr),
 425   _vm_result_oop(nullptr),
 426   _vm_result_metadata(nullptr),
 427 
 428   _current_pending_monitor(nullptr),
 429   _current_pending_monitor_is_from_java(true),
 430   _current_waiting_monitor(nullptr),
 431   _active_handles(nullptr),
 432   _free_handle_block(nullptr),
 433   _monitor_owner_id(0),
 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_disable_suspend(false),
 452   _is_in_java_upcall(false),
 453   _VTMS_transition_mark(false),
 454   _on_monitor_waited_event(false),
 455   _contended_entered_monitor(nullptr),
 456 #ifdef ASSERT
 457   _is_VTMS_transition_disabler(false),
 458 #endif
 459 #endif
 460   _jni_attach_state(_not_attaching_via_jni),
 461   _is_in_internal_oome_mark(false),
 462 #if INCLUDE_JVMCI
 463   _pending_deoptimization(-1),
 464   _pending_monitorenter(false),
 465   _pending_transfer_to_interpreter(false),
 466   _pending_failed_speculation(0),
 467   _jvmci{nullptr},
 468   _libjvmci_runtime(nullptr),
 469   _jvmci_counters(nullptr),
 470   _jvmci_reserved0(0),
 471   _jvmci_reserved1(0),
 472   _jvmci_reserved_oop0(nullptr),
 473   _live_nmethod(nullptr),
 474 #endif // INCLUDE_JVMCI
 475 
 476   _exception_oop(oop()),
 477   _exception_pc(nullptr),
 478   _exception_handler_pc(nullptr),
 479   _is_method_handle_return(0),
 480 
 481   _jni_active_critical(0),
 482   _pending_jni_exception_check_fn(nullptr),
 483   _depth_first_number(0),
 484 
 485   // JVMTI PopFrame support
 486   _popframe_condition(popframe_inactive),
 487   _frames_to_pop_failed_realloc(0),
 488 
 489   _cont_entry(nullptr),
 490   _cont_fastpath(nullptr),
 491   _cont_fastpath_thread_state(1),
 492   _held_monitor_count(0),
 493   _jni_monitor_count(0),
 494   _unlocked_inflated_monitor(nullptr),
 495 
 496   _preempt_alternate_return(nullptr),
 497   _preemption_cancelled(false),
 498   _pending_interrupted_exception(false),
 499 
 500   _handshake(this),
 501   _suspend_resume_manager(this, &_handshake._lock),
 502 
 503   _popframe_preserved_args(nullptr),
 504   _popframe_preserved_args_size(0),
 505 
 506   _jvmti_thread_state(nullptr),
 507   _interp_only_mode(0),
 508   _should_post_on_exceptions_flag(JNI_FALSE),
 509   _thread_stat(new ThreadStatistics()),
 510 
 511   _parker(),
 512 
 513   _class_to_be_initialized(nullptr),
 514   _class_being_initialized(nullptr),
 515 
 516   _SleepEvent(ParkEvent::Allocate(this)),
 517 
 518 #if INCLUDE_JFR
 519   _last_freeze_fail_result(freeze_ok),
 520 #endif
 521 
 522   _lock_stack(this),
 523   _om_cache(this) {
 524   set_jni_functions(jni_functions());
 525 
 526 #if INCLUDE_JVMCI
 527   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
 528   if (JVMCICounterSize > 0) {
 529     resize_counters(0, (int) JVMCICounterSize);
 530   }
 531 #endif // INCLUDE_JVMCI
 532 
 533   // Setup safepoint state info for this thread
 534   ThreadSafepointState::create(this);
 535 
 536   SafepointMechanism::initialize_header(this);
 537 
 538   set_requires_cross_modify_fence(false);
 539 
 540   pd_initialize();
 541   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
 542 }
 543 
 544 JavaThread* JavaThread::create_attaching_thread() {
 545   JavaThread* jt = new JavaThread();
 546   jt->_jni_attach_state = _attaching_via_jni;
 547   return jt;
 548 }
 549 
 550 // interrupt support
 551 
 552 void JavaThread::interrupt() {
 553   // All callers should have 'this' thread protected by a
 554   // ThreadsListHandle so that it cannot terminate and deallocate
 555   // itself.
 556   DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
 557 
 558   // For Windows _interrupt_event
 559   WINDOWS_ONLY(osthread()->set_interrupted(true);)
 560 
 561   // For Thread.sleep
 562   _SleepEvent->unpark();
 563 
 564   // For JSR166 LockSupport.park
 565   parker()->unpark();
 566 
 567   // For ObjectMonitor and JvmtiRawMonitor
 568   _ParkEvent->unpark();
 569 }
 570 
 571 bool JavaThread::is_interrupted(bool clear_interrupted) {
 572   DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
 573 
 574   if (_threadObj.peek() == nullptr) {
 575     // If there is no j.l.Thread then it is impossible to have
 576     // been interrupted. We can find null during VM initialization
 577     // or when a JNI thread is still in the process of attaching.
 578     // In such cases this must be the current thread.
 579     assert(this == Thread::current(), "invariant");
 580     return false;
 581   }
 582 
 583   bool interrupted = java_lang_Thread::interrupted(threadObj());
 584 
 585   // NOTE that since there is no "lock" around the interrupt and
 586   // is_interrupted operations, there is the possibility that the
 587   // interrupted flag will be "false" but that the
 588   // low-level events will be in the signaled state. This is
 589   // intentional. The effect of this is that Object.wait() and
 590   // LockSupport.park() will appear to have a spurious wakeup, which
 591   // is allowed and not harmful, and the possibility is so rare that
 592   // it is not worth the added complexity to add yet another lock.
 593   // For the sleep event an explicit reset is performed on entry
 594   // to JavaThread::sleep, so there is no early return. It has also been
 595   // recommended not to put the interrupted flag into the "event"
 596   // structure because it hides the issue.
 597   // Also, because there is no lock, we must only clear the interrupt
 598   // state if we are going to report that we were interrupted; otherwise
 599   // an interrupt that happens just after we read the field would be lost.
 600   if (interrupted && clear_interrupted) {
 601     assert(this == Thread::current(), "only the current thread can clear");
 602     java_lang_Thread::set_interrupted(threadObj(), false);
 603     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 604   }
 605   return interrupted;
 606 }
 607 
 608 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
 609 // the Java code in Object::wait which are not present in RawMonitorWait.
 610 bool JavaThread::get_and_clear_interrupted() {
 611   if (!is_interrupted(false)) {
 612     return false;
 613   }
 614   oop thread_oop = vthread_or_thread();
 615   bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
 616 
 617   if (!is_virtual) {
 618     return is_interrupted(true);
 619   }
 620   // Virtual thread: clear interrupt status for both virtual and
 621   // carrier threads under the interruptLock protection.
 622   JavaThread* current = JavaThread::current();
 623   HandleMark hm(current);
 624   Handle thread_h(current, thread_oop);
 625   ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
 626 
 627   // re-check the interrupt status under the interruptLock protection
 628   bool interrupted = java_lang_Thread::interrupted(thread_h());
 629 
 630   if (interrupted) {
 631     assert(this == Thread::current(), "only the current thread can clear");
 632     java_lang_Thread::set_interrupted(thread_h(), false);  // clear for virtual
 633     java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
 634     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 635   }
 636   return interrupted;
 637 }
 638 
 639 void JavaThread::block_if_vm_exited() {
 640   if (_terminated == _vm_exited) {
 641     // _vm_exited is set at safepoint, and Threads_lock is never released
 642     // so we will block here forever.
 643     // Here we can be doing a jump from a safe state to an unsafe state without
 644     // proper transition, but it happens after the final safepoint has begun so
 645     // this jump won't cause any safepoint problems.
 646     set_thread_state(_thread_in_vm);
 647     Threads_lock->lock();
 648     ShouldNotReachHere();
 649   }
 650 }
 651 
 652 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
 653   set_entry_point(entry_point);
 654   // Create the native thread itself.
 655   // %note runtime_23
 656   os::ThreadType thr_type = os::java_thread;
 657   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
 658                                                             os::java_thread;
 659   os::create_thread(this, thr_type, stack_sz);
 660   // The _osthread may be null here because we ran out of memory (too many threads active).
 661   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
 662   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
 663   // the exception consists of creating the exception object & initializing it, initialization
 664   // will leave the VM via a JavaCall and then all locks must be unlocked).
 665   //
 666   // The thread is still suspended when we reach here. Thread must be explicit started
 667   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
 668   // by calling Threads:add. The reason why this is not done here, is because the thread
 669   // object must be fully initialized (take a look at JVM_Start)
 670 }
 671 
 672 JavaThread::~JavaThread() {
 673 
 674   // Enqueue OopHandles for release by the service thread.
 675   add_oop_handles_for_release();
 676 
 677   // Return the sleep event to the free list
 678   ParkEvent::Release(_SleepEvent);
 679   _SleepEvent = nullptr;
 680 
 681   // Free any remaining  previous UnrollBlock
 682   vframeArray* old_array = vframe_array_last();
 683 
 684   if (old_array != nullptr) {
 685     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
 686     old_array->set_unroll_block(nullptr);
 687     delete old_info;
 688     delete old_array;
 689   }
 690 
 691   JvmtiDeferredUpdates* updates = deferred_updates();
 692   if (updates != nullptr) {
 693     // This can only happen if thread is destroyed before deoptimization occurs.
 694     assert(updates->count() > 0, "Updates holder not deleted");
 695     // free deferred updates.
 696     delete updates;
 697     set_deferred_updates(nullptr);
 698   }
 699 
 700   // All Java related clean up happens in exit
 701   ThreadSafepointState::destroy(this);
 702   if (_thread_stat != nullptr) delete _thread_stat;
 703 
 704 #if INCLUDE_JVMCI
 705   if (JVMCICounterSize > 0) {
 706     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
 707   }
 708 #endif // INCLUDE_JVMCI
 709 }
 710 
 711 
 712 // First JavaThread specific code executed by a new Java thread.
 713 void JavaThread::pre_run() {
 714   // empty - see comments in run()
 715 }
 716 
 717 // The main routine called by a new Java thread. This isn't overridden
 718 // by subclasses, instead different subclasses define a different "entry_point"
 719 // which defines the actual logic for that kind of thread.
 720 void JavaThread::run() {
 721   // initialize thread-local alloc buffer related fields
 722   initialize_tlab();
 723 
 724   _stack_overflow_state.create_stack_guard_pages();
 725 
 726   cache_global_variables();
 727 
 728   // Thread is now sufficiently initialized to be handled by the safepoint code as being
 729   // in the VM. Change thread state from _thread_new to _thread_in_vm
 730   assert(this->thread_state() == _thread_new, "wrong thread state");
 731   set_thread_state(_thread_in_vm);
 732 
 733   // Before a thread is on the threads list it is always safe, so after leaving the
 734   // _thread_new we should emit a instruction barrier. The distance to modified code
 735   // from here is probably far enough, but this is consistent and safe.
 736   OrderAccess::cross_modify_fence();
 737 
 738   assert(JavaThread::current() == this, "sanity check");
 739   assert(!Thread::current()->owns_locks(), "sanity check");
 740 
 741   JFR_ONLY(Jfr::on_thread_start(this);)
 742 
 743   DTRACE_THREAD_PROBE(start, this);
 744 
 745   // This operation might block. We call that after all safepoint checks for a new thread has
 746   // been completed.
 747   set_active_handles(JNIHandleBlock::allocate_block());
 748 
 749   if (JvmtiExport::should_post_thread_life()) {
 750     JvmtiExport::post_thread_start(this);
 751 
 752   }
 753 
 754   if (AlwaysPreTouchStacks) {
 755     pretouch_stack();
 756   }
 757 
 758   // We call another function to do the rest so we are sure that the stack addresses used
 759   // from there will be lower than the stack base just computed.
 760   thread_main_inner();
 761 }
 762 
 763 void JavaThread::thread_main_inner() {
 764   assert(JavaThread::current() == this, "sanity check");
 765   assert(_threadObj.peek() != nullptr, "just checking");
 766 
 767   // Execute thread entry point unless this thread has a pending exception.
 768   // Note: Due to JVMTI StopThread we can have pending exceptions already!
 769   if (!this->has_pending_exception()) {
 770     {
 771       ResourceMark rm(this);
 772       this->set_native_thread_name(this->name());
 773     }
 774     HandleMark hm(this);
 775     this->entry_point()(this, this);
 776   }
 777 
 778   DTRACE_THREAD_PROBE(stop, this);
 779 
 780   // Cleanup is handled in post_run()
 781 }
 782 
 783 // Shared teardown for all JavaThreads
 784 void JavaThread::post_run() {
 785   this->exit(false);
 786   this->unregister_thread_stack_with_NMT();
 787   // Defer deletion to here to ensure 'this' is still referenceable in call_run
 788   // for any shared tear-down.
 789   this->smr_delete();
 790 }
 791 
 792 static void ensure_join(JavaThread* thread) {
 793   // We do not need to grab the Threads_lock, since we are operating on ourself.
 794   Handle threadObj(thread, thread->threadObj());
 795   assert(threadObj.not_null(), "java thread object must exist");
 796   ObjectLocker lock(threadObj, thread);
 797   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
 798   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
 799   // Clear the native thread instance - this makes isAlive return false and allows the join()
 800   // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
 801   // requirements.
 802   assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
 803   java_lang_Thread::release_set_thread(threadObj(), nullptr);
 804   lock.notify_all(thread);
 805   // Ignore pending exception, since we are exiting anyway
 806   thread->clear_pending_exception();
 807 }
 808 
 809 static bool is_daemon(oop threadObj) {
 810   return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
 811 }
 812 
 813 // For any new cleanup additions, please check to see if they need to be applied to
 814 // cleanup_failed_attach_current_thread as well.
 815 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
 816   assert(this == JavaThread::current(), "thread consistency check");
 817   assert(!is_exiting(), "should not be exiting or terminated already");
 818 
 819   elapsedTimer _timer_exit_phase1;
 820   elapsedTimer _timer_exit_phase2;
 821   elapsedTimer _timer_exit_phase3;
 822   elapsedTimer _timer_exit_phase4;
 823 
 824   om_clear_monitor_cache();
 825 
 826   if (log_is_enabled(Debug, os, thread, timer)) {
 827     _timer_exit_phase1.start();
 828   }
 829 
 830   HandleMark hm(this);
 831   Handle uncaught_exception(this, this->pending_exception());
 832   this->clear_pending_exception();
 833   Handle threadObj(this, this->threadObj());
 834   assert(threadObj.not_null(), "Java thread object should be created");
 835 
 836   if (!destroy_vm) {
 837     if (uncaught_exception.not_null()) {
 838       EXCEPTION_MARK;
 839       // Call method Thread.dispatchUncaughtException().
 840       Klass* thread_klass = vmClasses::Thread_klass();
 841       JavaValue result(T_VOID);
 842       JavaCalls::call_virtual(&result,
 843                               threadObj, thread_klass,
 844                               vmSymbols::dispatchUncaughtException_name(),
 845                               vmSymbols::throwable_void_signature(),
 846                               uncaught_exception,
 847                               THREAD);
 848       if (HAS_PENDING_EXCEPTION) {
 849         ResourceMark rm(this);
 850         jio_fprintf(defaultStream::error_stream(),
 851                     "\nException: %s thrown from the UncaughtExceptionHandler"
 852                     " in thread \"%s\"\n",
 853                     pending_exception()->klass()->external_name(),
 854                     name());
 855         CLEAR_PENDING_EXCEPTION;
 856       }
 857     }
 858 
 859     if (!is_Compiler_thread()) {
 860       // We have finished executing user-defined Java code and now have to do the
 861       // implementation specific clean-up by calling Thread.exit(). We prevent any
 862       // asynchronous exceptions from being delivered while in Thread.exit()
 863       // to ensure the clean-up is not corrupted.
 864       NoAsyncExceptionDeliveryMark _no_async(this);
 865 
 866       EXCEPTION_MARK;
 867       JavaValue result(T_VOID);
 868       Klass* thread_klass = vmClasses::Thread_klass();
 869       JavaCalls::call_virtual(&result,
 870                               threadObj, thread_klass,
 871                               vmSymbols::exit_method_name(),
 872                               vmSymbols::void_method_signature(),
 873                               THREAD);
 874       CLEAR_PENDING_EXCEPTION;
 875     }
 876 
 877     // notify JVMTI
 878     if (JvmtiExport::should_post_thread_life()) {
 879       JvmtiExport::post_thread_end(this);
 880     }
 881   } else {
 882     // before_exit() has already posted JVMTI THREAD_END events
 883   }
 884 
 885   // Cleanup any pending async exception now since we cannot access oops after
 886   // BarrierSet::barrier_set()->on_thread_detach() has been executed.
 887   if (has_async_exception_condition()) {
 888     handshake_state()->clean_async_exception_operation();
 889   }
 890 
 891   // The careful dance between thread suspension and exit is handled here.
 892   // Since we are in thread_in_vm state and suspension is done with handshakes,
 893   // we can just put in the exiting state and it will be correctly handled.
 894   // Also, no more async exceptions will be added to the queue after this point.
 895   set_terminated(_thread_exiting);
 896   ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
 897 
 898   if (log_is_enabled(Debug, os, thread, timer)) {
 899     _timer_exit_phase1.stop();
 900     _timer_exit_phase2.start();
 901   }
 902 
 903   // Capture daemon status before the thread is marked as terminated.
 904   bool daemon = is_daemon(threadObj());
 905 
 906   // Notify waiters on thread object. This has to be done after exit() is called
 907   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
 908   // group should have the destroyed bit set before waiters are notified).
 909   ensure_join(this);
 910   assert(!this->has_pending_exception(), "ensure_join should have cleared");
 911 
 912   if (log_is_enabled(Debug, os, thread, timer)) {
 913     _timer_exit_phase2.stop();
 914     _timer_exit_phase3.start();
 915   }
 916   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
 917   // held by this thread must be released. The spec does not distinguish
 918   // between JNI-acquired and regular Java monitors. We can only see
 919   // regular Java monitors here if monitor enter-exit matching is broken.
 920   //
 921   // ensure_join() ignores IllegalThreadStateExceptions, and so does
 922   // ObjectSynchronizer::release_monitors_owned_by_thread().
 923   if (exit_type == jni_detach) {
 924     // Sanity check even though JNI DetachCurrentThread() would have
 925     // returned JNI_ERR if there was a Java frame. JavaThread exit
 926     // should be done executing Java code by the time we get here.
 927     assert(!this->has_last_Java_frame(),
 928            "should not have a Java frame when detaching or exiting");
 929     ObjectSynchronizer::release_monitors_owned_by_thread(this);
 930     assert(!this->has_pending_exception(), "release_monitors should have cleared");
 931     // Check for monitor counts being out of sync.
 932     assert(held_monitor_count() == jni_monitor_count(),
 933            "held monitor count should be equal to jni: %zd != %zd",
 934            held_monitor_count(), jni_monitor_count());
 935     // All in-use monitors, including JNI-locked ones, should have been released above.
 936     assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
 937            held_monitor_count());
 938   } else {
 939     // Check for monitor counts being out of sync.
 940     assert(held_monitor_count() == jni_monitor_count(),
 941            "held monitor count should be equal to jni: %zd != %zd",
 942            held_monitor_count(), jni_monitor_count());
 943     // It is possible that a terminating thread failed to unlock monitors it locked
 944     // via JNI so we don't assert the count is zero.
 945   }
 946 
 947   if (CheckJNICalls && jni_monitor_count() > 0) {
 948     // We would like a fatal here, but due to we never checked this before there
 949     // is a lot of tests which breaks, even with an error log.
 950     log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
 951                    exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
 952   }
 953 
 954   // These things needs to be done while we are still a Java Thread. Make sure that thread
 955   // is in a consistent state, in case GC happens
 956   JFR_ONLY(Jfr::on_thread_exit(this);)
 957 
 958   if (active_handles() != nullptr) {
 959     JNIHandleBlock* block = active_handles();
 960     set_active_handles(nullptr);
 961     JNIHandleBlock::release_block(block);
 962   }
 963 
 964   if (free_handle_block() != nullptr) {
 965     JNIHandleBlock* block = free_handle_block();
 966     set_free_handle_block(nullptr);
 967     JNIHandleBlock::release_block(block);
 968   }
 969 
 970   // These have to be removed while this is still a valid thread.
 971   _stack_overflow_state.remove_stack_guard_pages();
 972 
 973   if (UseTLAB) {
 974     retire_tlab();
 975   }
 976 
 977   if (JvmtiEnv::environments_might_exist()) {
 978     JvmtiExport::cleanup_thread(this);
 979   }
 980 
 981   // We need to cache the thread name for logging purposes below as once
 982   // we have called on_thread_detach this thread must not access any oops.
 983   char* thread_name = nullptr;
 984   if (log_is_enabled(Debug, os, thread, timer)) {
 985     ResourceMark rm(this);
 986     thread_name = os::strdup(name());
 987   }
 988 
 989   if (log_is_enabled(Info, os, thread)) {
 990     ResourceMark rm(this);
 991     log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
 992                          exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
 993                          name(), os::current_thread_id());
 994   }
 995 
 996   if (log_is_enabled(Debug, os, thread, timer)) {
 997     _timer_exit_phase3.stop();
 998     _timer_exit_phase4.start();
 999   }
1000 
1001 #if INCLUDE_JVMCI
1002   if (JVMCICounterSize > 0) {
1003     if (jvmci_counters_include(this)) {
1004       for (int i = 0; i < JVMCICounterSize; i++) {
1005         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1006       }
1007     }
1008   }
1009 #endif // INCLUDE_JVMCI
1010 
1011   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1012   // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1013   Threads::remove(this, daemon);
1014 
1015   if (log_is_enabled(Debug, os, thread, timer)) {
1016     _timer_exit_phase4.stop();
1017     log_debug(os, thread, timer)("name='%s'"
1018                                  ", exit-phase1=" JLONG_FORMAT
1019                                  ", exit-phase2=" JLONG_FORMAT
1020                                  ", exit-phase3=" JLONG_FORMAT
1021                                  ", exit-phase4=" JLONG_FORMAT,
1022                                  thread_name,
1023                                  _timer_exit_phase1.milliseconds(),
1024                                  _timer_exit_phase2.milliseconds(),
1025                                  _timer_exit_phase3.milliseconds(),
1026                                  _timer_exit_phase4.milliseconds());
1027     os::free(thread_name);
1028   }
1029 }
1030 
1031 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1032   if (active_handles() != nullptr) {
1033     JNIHandleBlock* block = active_handles();
1034     set_active_handles(nullptr);
1035     JNIHandleBlock::release_block(block);
1036   }
1037 
1038   if (free_handle_block() != nullptr) {
1039     JNIHandleBlock* block = free_handle_block();
1040     set_free_handle_block(nullptr);
1041     JNIHandleBlock::release_block(block);
1042   }
1043 
1044   // These have to be removed while this is still a valid thread.
1045   _stack_overflow_state.remove_stack_guard_pages();
1046 
1047   if (UseTLAB) {
1048     retire_tlab();
1049   }
1050 
1051   Threads::remove(this, is_daemon);
1052 }
1053 
1054 JavaThread* JavaThread::active() {
1055   Thread* thread = Thread::current();
1056   if (thread->is_Java_thread()) {
1057     return JavaThread::cast(thread);
1058   } else {
1059     assert(thread->is_VM_thread(), "this must be a vm thread");
1060     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1061     JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1062     return ret;
1063   }
1064 }
1065 
1066 bool JavaThread::is_lock_owned(address adr) const {
1067   assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1068   return is_in_full_stack(adr);
1069 }
1070 
1071 oop JavaThread::exception_oop() const {
1072   return Atomic::load(&_exception_oop);
1073 }
1074 
1075 void JavaThread::set_exception_oop(oop o) {
1076   Atomic::store(&_exception_oop, o);
1077 }
1078 
1079 void JavaThread::handle_special_runtime_exit_condition() {
1080   if (is_obj_deopt_suspend()) {
1081     frame_anchor()->make_walkable();
1082     wait_for_object_deoptimization();
1083   }
1084 }
1085 
1086 
1087 // Asynchronous exceptions support
1088 //
1089 void JavaThread::handle_async_exception(oop java_throwable) {
1090   assert(java_throwable != nullptr, "should have an _async_exception to throw");
1091   assert(!is_at_poll_safepoint(), "should have never called this method");
1092 
1093   if (has_last_Java_frame()) {
1094     frame f = last_frame();
1095     if (f.is_runtime_frame()) {
1096       // If the topmost frame is a runtime stub, then we are calling into
1097       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1098       // must deoptimize the caller before continuing, as the compiled exception
1099       // handler table may not be valid.
1100       RegisterMap reg_map(this,
1101                           RegisterMap::UpdateMap::skip,
1102                           RegisterMap::ProcessFrames::include,
1103                           RegisterMap::WalkContinuation::skip);
1104       frame compiled_frame = f.sender(&reg_map);
1105       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1106         Deoptimization::deoptimize(this, compiled_frame);
1107       }
1108     }
1109   }
1110 
1111   // We cannot call Exceptions::_throw(...) here because we cannot block
1112   set_pending_exception(java_throwable, __FILE__, __LINE__);
1113 
1114   clear_scopedValueBindings();
1115 
1116   LogTarget(Info, exceptions) lt;
1117   if (lt.is_enabled()) {
1118     ResourceMark rm;
1119     LogStream ls(lt);
1120     ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1121     if (has_last_Java_frame()) {
1122       frame f = last_frame();
1123       ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1124     }
1125     ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1126   }
1127 }
1128 
1129 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1130   // Do not throw asynchronous exceptions against the compiler thread
1131   // or if the thread is already exiting.
1132   if (!can_call_java() || is_exiting()) {
1133     delete aehc;
1134     return;
1135   }
1136 
1137   oop exception = aehc->exception();
1138   Handshake::execute(aehc, this);  // Install asynchronous handshake
1139 
1140   ResourceMark rm;
1141   if (log_is_enabled(Info, exceptions)) {
1142     log_info(exceptions)("Pending Async. exception installed of type: %s",
1143                          InstanceKlass::cast(exception->klass())->external_name());
1144   }
1145   // for AbortVMOnException flag
1146   Exceptions::debug_check_abort(exception->klass()->external_name());
1147 
1148   oop vt_oop = vthread();
1149   if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1150     // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1151     this->interrupt();
1152   }
1153 }
1154 
1155 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1156   AsyncExceptionHandshakeClosure* _aehc;
1157 public:
1158   InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1159     HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1160   ~InstallAsyncExceptionHandshakeClosure() {
1161     // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1162     delete _aehc;
1163   }
1164   void do_thread(Thread* thr) {
1165     JavaThread* target = JavaThread::cast(thr);
1166     target->install_async_exception(_aehc);
1167     _aehc = nullptr;
1168   }
1169 };
1170 
1171 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1172   OopHandle e(Universe::vm_global(), java_throwable);
1173   InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1174   Handshake::execute(&iaeh, target);
1175 }
1176 
1177 #if INCLUDE_JVMTI
1178 void JavaThread::set_is_in_VTMS_transition(bool val) {
1179   assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1180   _is_in_VTMS_transition = val;
1181 }
1182 
1183 #ifdef ASSERT
1184 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1185   _is_VTMS_transition_disabler = val;
1186 }
1187 #endif
1188 #endif
1189 
1190 // External suspension mechanism.
1191 //
1192 // Guarantees on return (for a valid target thread):
1193 //   - Target thread will not execute any new bytecode.
1194 //   - Target thread will not enter any new monitors.
1195 //
1196 bool JavaThread::java_suspend(bool register_vthread_SR) {
1197 #if INCLUDE_JVMTI
1198   // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1199   assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1200   assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1201 #endif
1202 
1203   guarantee(Thread::is_JavaThread_protected(/* target */ this),
1204             "target JavaThread is not protected in calling context.");
1205   return this->suspend_resume_manager()->suspend(register_vthread_SR);
1206 }
1207 
1208 bool JavaThread::java_resume(bool register_vthread_SR) {
1209   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1210             "missing ThreadsListHandle in calling context.");
1211   return this->suspend_resume_manager()->resume(register_vthread_SR);
1212 }
1213 
1214 // Wait for another thread to perform object reallocation and relocking on behalf of
1215 // this thread. The current thread is required to change to _thread_blocked in order
1216 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1217 // handshake safe, the other thread can complete the handshake used to synchronize
1218 // with this thread and then perform the reallocation and relocking.
1219 // See EscapeBarrier::sync_and_suspend_*()
1220 
1221 void JavaThread::wait_for_object_deoptimization() {
1222   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1223   assert(this == Thread::current(), "invariant");
1224 
1225   bool spin_wait = os::is_MP();
1226   do {
1227     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1228     // Wait for object deoptimization if requested.
1229     if (spin_wait) {
1230       // A single deoptimization is typically very short. Microbenchmarks
1231       // showed 5% better performance when spinning.
1232       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1233       SpinYield spin(spin_limit);
1234       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1235         spin.wait();
1236       }
1237       // Spin just once
1238       spin_wait = false;
1239     } else {
1240       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1241       if (is_obj_deopt_suspend()) {
1242         ml.wait();
1243       }
1244     }
1245     // A handshake for obj. deoptimization suspend could have been processed so
1246     // we must check after processing.
1247   } while (is_obj_deopt_suspend());
1248 }
1249 
1250 #ifdef ASSERT
1251 // Verify the JavaThread has not yet been published in the Threads::list, and
1252 // hence doesn't need protection from concurrent access at this stage.
1253 void JavaThread::verify_not_published() {
1254   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1255   // since an unpublished JavaThread doesn't participate in the
1256   // Thread-SMR protocol for keeping a ThreadsList alive.
1257   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1258 }
1259 #endif
1260 
1261 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1262 // pending, when _suspend_flags is non-zero or when we need to process a stack
1263 // watermark. Also check for pending async exceptions (except unsafe access error).
1264 // Note only the native==>Java barriers can call this function when thread state
1265 // is _thread_in_native_trans.
1266 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1267   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1268   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1269 
1270   thread->set_thread_state(_thread_in_vm);
1271 
1272   // Enable WXWrite: called directly from interpreter native wrapper.
1273   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1274 
1275   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1276 
1277   // After returning from native, it could be that the stack frames are not
1278   // yet safe to use. We catch such situations in the subsequent stack watermark
1279   // barrier, which will trap unsafe stack frames.
1280   StackWatermarkSet::before_unwind(thread);
1281 }
1282 
1283 #ifndef PRODUCT
1284 // Deoptimization
1285 // Function for testing deoptimization
1286 void JavaThread::deoptimize() {
1287   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1288   bool deopt = false;           // Dump stack only if a deopt actually happens.
1289   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1290   // Iterate over all frames in the thread and deoptimize
1291   for (; !fst.is_done(); fst.next()) {
1292     if (fst.current()->can_be_deoptimized()) {
1293 
1294       if (only_at) {
1295         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1296         // consists of comma or carriage return separated numbers so
1297         // search for the current bci in that string.
1298         address    pc = fst.current()->pc();
1299         nmethod*   nm = fst.current()->cb()->as_nmethod();
1300         ScopeDesc* sd = nm->scope_desc_at(pc);
1301         char buffer[8];
1302         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1303         size_t len = strlen(buffer);
1304         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1305         while (found != nullptr) {
1306           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1307               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1308             // Check that the bci found is bracketed by terminators.
1309             break;
1310           }
1311           found = strstr(found + 1, buffer);
1312         }
1313         if (!found) {
1314           continue;
1315         }
1316       }
1317 
1318       if (DebugDeoptimization && !deopt) {
1319         deopt = true; // One-time only print before deopt
1320         tty->print_cr("[BEFORE Deoptimization]");
1321         trace_frames();
1322         trace_stack();
1323       }
1324       Deoptimization::deoptimize(this, *fst.current());
1325     }
1326   }
1327 
1328   if (DebugDeoptimization && deopt) {
1329     tty->print_cr("[AFTER Deoptimization]");
1330     trace_frames();
1331   }
1332 }
1333 
1334 
1335 // Make zombies
1336 void JavaThread::make_zombies() {
1337   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1338     if (fst.current()->can_be_deoptimized()) {
1339       // it is a Java nmethod
1340       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1341       assert(nm != nullptr, "did not find nmethod");
1342       nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1343     }
1344   }
1345 }
1346 #endif // PRODUCT
1347 
1348 
1349 void JavaThread::deoptimize_marked_methods() {
1350   if (!has_last_Java_frame()) return;
1351   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1352   for (; !fst.is_done(); fst.next()) {
1353     if (fst.current()->should_be_deoptimized()) {
1354       Deoptimization::deoptimize(this, *fst.current());
1355     }
1356   }
1357 }
1358 
1359 #ifdef ASSERT
1360 void JavaThread::verify_frame_info() {
1361   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1362          (has_last_Java_frame() && java_call_counter() > 0),
1363          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1364          has_last_Java_frame() ? "true" : "false", java_call_counter());
1365 }
1366 #endif
1367 
1368 // Push on a new block of JNI handles.
1369 void JavaThread::push_jni_handle_block() {
1370   // Allocate a new block for JNI handles.
1371   // Inlined code from jni_PushLocalFrame()
1372   JNIHandleBlock* old_handles = active_handles();
1373   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1374   assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1375   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1376   set_active_handles(new_handles);
1377 }
1378 
1379 // Pop off the current block of JNI handles.
1380 void JavaThread::pop_jni_handle_block() {
1381   // Release our JNI handle block
1382   JNIHandleBlock* old_handles = active_handles();
1383   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1384   assert(new_handles != nullptr, "should never set active handles to null");
1385   set_active_handles(new_handles);
1386   old_handles->set_pop_frame_link(nullptr);
1387   JNIHandleBlock::release_block(old_handles, this);
1388 }
1389 
1390 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1391   // Verify that the deferred card marks have been flushed.
1392   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1393 
1394   // Traverse the GCHandles
1395   Thread::oops_do_no_frames(f, cf);
1396 
1397   if (active_handles() != nullptr) {
1398     active_handles()->oops_do(f);
1399   }
1400 
1401   DEBUG_ONLY(verify_frame_info();)
1402 
1403   assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1404   // If we have deferred set_locals there might be oops waiting to be
1405   // written
1406   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1407   if (list != nullptr) {
1408     for (int i = 0; i < list->length(); i++) {
1409       list->at(i)->oops_do(f);
1410     }
1411   }
1412 
1413   // Traverse instance variables at the end since the GC may be moving things
1414   // around using this function
1415   f->do_oop((oop*) &_vm_result_oop);
1416   f->do_oop((oop*) &_exception_oop);
1417 #if INCLUDE_JVMCI
1418   f->do_oop((oop*) &_jvmci_reserved_oop0);
1419 
1420   if (_live_nmethod != nullptr && cf != nullptr) {
1421     cf->do_nmethod(_live_nmethod);
1422   }
1423 #endif
1424 
1425   if (jvmti_thread_state() != nullptr) {
1426     jvmti_thread_state()->oops_do(f, cf);
1427   }
1428 
1429   // The continuation oops are really on the stack. But there is typically at most
1430   // one of those per thread, so we handle them here in the oops_do_no_frames part
1431   // so that we don't have to sprinkle as many stack watermark checks where these
1432   // oops are used. We just need to make sure the thread has started processing.
1433   ContinuationEntry* entry = _cont_entry;
1434   while (entry != nullptr) {
1435     f->do_oop((oop*)entry->cont_addr());
1436     f->do_oop((oop*)entry->chunk_addr());
1437     entry = entry->parent();
1438   }
1439 
1440   if (LockingMode == LM_LIGHTWEIGHT) {
1441     lock_stack().oops_do(f);
1442   }
1443 }
1444 
1445 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1446   if (!has_last_Java_frame()) {
1447     return;
1448   }
1449   // Finish any pending lazy GC activity for the frames
1450   StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1451   // Traverse the execution stack
1452   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1453     fst.current()->oops_do(f, cf, fst.register_map());
1454   }
1455 }
1456 
1457 #ifdef ASSERT
1458 void JavaThread::verify_states_for_handshake() {
1459   // This checks that the thread has a correct frame state during a handshake.
1460   verify_frame_info();
1461 }
1462 #endif
1463 
1464 void JavaThread::nmethods_do(NMethodClosure* cf) {
1465   DEBUG_ONLY(verify_frame_info();)
1466   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1467 
1468   if (has_last_Java_frame()) {
1469     // Traverse the execution stack
1470     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1471       fst.current()->nmethod_do(cf);
1472     }
1473   }
1474 
1475   if (jvmti_thread_state() != nullptr) {
1476     jvmti_thread_state()->nmethods_do(cf);
1477   }
1478 
1479 #if INCLUDE_JVMCI
1480   if (_live_nmethod != nullptr) {
1481     cf->do_nmethod(_live_nmethod);
1482   }
1483 #endif
1484 }
1485 
1486 void JavaThread::metadata_do(MetadataClosure* f) {
1487   if (has_last_Java_frame()) {
1488     // Traverse the execution stack to call f() on the methods in the stack
1489     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1490       fst.current()->metadata_do(f);
1491     }
1492   } else if (is_Compiler_thread()) {
1493     // need to walk ciMetadata in current compile tasks to keep alive.
1494     CompilerThread* ct = (CompilerThread*)this;
1495     if (ct->env() != nullptr) {
1496       ct->env()->metadata_do(f);
1497     }
1498     CompileTask* task = ct->task();
1499     if (task != nullptr) {
1500       task->metadata_do(f);
1501     }
1502   }
1503 }
1504 
1505 // Printing
1506 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1507   switch (_thread_state) {
1508   case _thread_uninitialized:     return "_thread_uninitialized";
1509   case _thread_new:               return "_thread_new";
1510   case _thread_new_trans:         return "_thread_new_trans";
1511   case _thread_in_native:         return "_thread_in_native";
1512   case _thread_in_native_trans:   return "_thread_in_native_trans";
1513   case _thread_in_vm:             return "_thread_in_vm";
1514   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1515   case _thread_in_Java:           return "_thread_in_Java";
1516   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1517   case _thread_blocked:           return "_thread_blocked";
1518   case _thread_blocked_trans:     return "_thread_blocked_trans";
1519   default:                        return "unknown thread state";
1520   }
1521 }
1522 
1523 void JavaThread::print_thread_state_on(outputStream *st) const {
1524   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1525 }
1526 
1527 // Called by Threads::print() for VM_PrintThreads operation
1528 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1529   st->print_raw("\"");
1530   st->print_raw(name());
1531   st->print_raw("\" ");
1532   oop thread_oop = threadObj();
1533   if (thread_oop != nullptr) {
1534     st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1535     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
1536     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1537   }
1538   Thread::print_on(st, print_extended_info);
1539   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1540   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1541   if (thread_oop != nullptr) {
1542     if (is_vthread_mounted()) {
1543       st->print_cr("   Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1544     } else {
1545       st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1546     }
1547   }
1548 #ifndef PRODUCT
1549   _safepoint_state->print_on(st);
1550 #endif // PRODUCT
1551   if (is_Compiler_thread()) {
1552     CompileTask *task = ((CompilerThread*)this)->task();
1553     if (task != nullptr) {
1554       st->print("   Compiling: ");
1555       task->print(st, nullptr, true, false);
1556     } else {
1557       st->print("   No compile task");
1558     }
1559     st->cr();
1560   }
1561 }
1562 
1563 void JavaThread::print() const { print_on(tty); }
1564 
1565 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1566   st->print("%s", get_thread_name_string(buf, buflen));
1567 }
1568 
1569 // Called by fatal error handler. The difference between this and
1570 // JavaThread::print() is that we can't grab lock or allocate memory.
1571 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1572   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1573   Thread* current = Thread::current_or_null_safe();
1574   assert(current != nullptr, "cannot be called by a detached thread");
1575   st->fill_to(60);
1576   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1577     // Only access threadObj() if current thread is not a JavaThread
1578     // or if it is a JavaThread that can safely access oops.
1579     oop thread_obj = threadObj();
1580     if (thread_obj != nullptr) {
1581       st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : "       ");
1582     }
1583   }
1584   st->print(" [");
1585   st->print("%s", _get_thread_state_name(_thread_state));
1586   if (osthread()) {
1587     st->print(", id=%d", osthread()->thread_id());
1588   }
1589   // Use raw field members for stack base/size as this could be
1590   // called before a thread has run enough to initialize them.
1591   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1592             p2i(_stack_base - _stack_size), p2i(_stack_base),
1593             PROPERFMTARGS(_stack_size));
1594   st->print("]");
1595 
1596   ThreadsSMRSupport::print_info_on(this, st);
1597   return;
1598 }
1599 
1600 
1601 // Verification
1602 
1603 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1604   // ignore if there is no stack
1605   if (!has_last_Java_frame()) return;
1606   // traverse the stack frames. Starts from top frame.
1607   for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1608     frame* fr = fst.current();
1609     f(fr, fst.register_map());
1610   }
1611 }
1612 
1613 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1614 
1615 void JavaThread::verify() {
1616   // Verify oops in the thread.
1617   oops_do(&VerifyOopClosure::verify_oop, nullptr);
1618 
1619   // Verify the stack frames.
1620   frames_do(frame_verify);
1621 }
1622 
1623 // CR 6300358 (sub-CR 2137150)
1624 // Most callers of this method assume that it can't return null but a
1625 // thread may not have a name whilst it is in the process of attaching to
1626 // the VM - see CR 6412693, and there are places where a JavaThread can be
1627 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1628 // if vm exit occurs during initialization). These cases can all be accounted
1629 // for such that this method never returns null.
1630 const char* JavaThread::name() const  {
1631   if (Thread::is_JavaThread_protected(/* target */ this)) {
1632     // The target JavaThread is protected so get_thread_name_string() is safe:
1633     return get_thread_name_string();
1634   }
1635 
1636   // The target JavaThread is not protected so we return the default:
1637   return Thread::name();
1638 }
1639 
1640 // Like name() but doesn't include the protection check. This must only be
1641 // called when it is known to be safe, even though the protection check can't tell
1642 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1643 const char* JavaThread::name_raw() const  {
1644   return get_thread_name_string();
1645 }
1646 
1647 // Returns a non-null representation of this thread's name, or a suitable
1648 // descriptive string if there is no set name.
1649 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1650   const char* name_str;
1651 #ifdef ASSERT
1652   Thread* current = Thread::current_or_null_safe();
1653   assert(current != nullptr, "cannot be called by a detached thread");
1654   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1655     // Only access threadObj() if current thread is not a JavaThread
1656     // or if it is a JavaThread that can safely access oops.
1657 #endif
1658     oop thread_obj = threadObj();
1659     if (thread_obj != nullptr) {
1660       oop name = java_lang_Thread::name(thread_obj);
1661       if (name != nullptr) {
1662         if (buf == nullptr) {
1663           name_str = java_lang_String::as_utf8_string(name);
1664         } else {
1665           name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1666         }
1667       } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1668         name_str = "<no-name - thread is attaching>";
1669       } else {
1670         name_str = "<un-named>";
1671       }
1672     } else {
1673       name_str = Thread::name();
1674     }
1675 #ifdef ASSERT
1676   } else {
1677     // Current JavaThread has exited...
1678     if (current == this) {
1679       // ... and is asking about itself:
1680       name_str = "<no-name - current JavaThread has exited>";
1681     } else {
1682       // ... and it can't safely determine this JavaThread's name so
1683       // use the default thread name.
1684       name_str = Thread::name();
1685     }
1686   }
1687 #endif
1688   assert(name_str != nullptr, "unexpected null thread name");
1689   return name_str;
1690 }
1691 
1692 // Helper to extract the name from the thread oop for logging.
1693 const char* JavaThread::name_for(oop thread_obj) {
1694   assert(thread_obj != nullptr, "precondition");
1695   oop name = java_lang_Thread::name(thread_obj);
1696   const char* name_str;
1697   if (name != nullptr) {
1698     name_str = java_lang_String::as_utf8_string(name);
1699   } else {
1700     name_str = "<un-named>";
1701   }
1702   return name_str;
1703 }
1704 
1705 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1706 
1707   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1708   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1709   // Link Java Thread object <-> C++ Thread
1710 
1711   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1712   // and put it into a new Handle.  The Handle "thread_oop" can then
1713   // be used to pass the C++ thread object to other methods.
1714 
1715   // Set the Java level thread object (jthread) field of the
1716   // new thread (a JavaThread *) to C++ thread object using the
1717   // "thread_oop" handle.
1718 
1719   // Set the thread field (a JavaThread *) of the
1720   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1721 
1722   Handle thread_oop(Thread::current(),
1723                     JNIHandles::resolve_non_null(jni_thread));
1724   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1725          "must be initialized");
1726   set_threadOopHandles(thread_oop());
1727   set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1728 
1729   if (prio == NoPriority) {
1730     prio = java_lang_Thread::priority(thread_oop());
1731     assert(prio != NoPriority, "A valid priority should be present");
1732   }
1733 
1734   // Push the Java priority down to the native thread; needs Threads_lock
1735   Thread::set_priority(this, prio);
1736 
1737   // Add the new thread to the Threads list and set it in motion.
1738   // We must have threads lock in order to call Threads::add.
1739   // It is crucial that we do not block before the thread is
1740   // added to the Threads list for if a GC happens, then the java_thread oop
1741   // will not be visited by GC.
1742   Threads::add(this);
1743   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1744   // on a ThreadsList. We don't want to wait for the release when the
1745   // Theads_lock is dropped somewhere in the caller since the JavaThread*
1746   // is already visible to JVM/TI via the ThreadsList.
1747   java_lang_Thread::release_set_thread(thread_oop(), this);
1748 }
1749 
1750 oop JavaThread::current_park_blocker() {
1751   // Support for JSR-166 locks
1752   oop thread_oop = threadObj();
1753   if (thread_oop != nullptr) {
1754     return java_lang_Thread::park_blocker(thread_oop);
1755   }
1756   return nullptr;
1757 }
1758 
1759 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1760 // This is the external format, selecting the platform or vthread
1761 // as applicable, and allowing for a native-only stack.
1762 void JavaThread::print_jni_stack() {
1763   assert(this == JavaThread::current(), "Can't print stack of other threads");
1764   if (!has_last_Java_frame()) {
1765     ResourceMark rm(this);
1766     char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1767     if (buf == nullptr) {
1768       tty->print_cr("Unable to print native stack - out of memory");
1769       return;
1770     }
1771     NativeStackPrinter nsp(this);
1772     address lastpc = nullptr;
1773     nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1774                     true /*print_source_info */, -1 /* max stack */ );
1775   } else {
1776     print_active_stack_on(tty);
1777   }
1778 }
1779 
1780 void JavaThread::print_stack_on(outputStream* st) {
1781   if (!has_last_Java_frame()) return;
1782 
1783   Thread* current_thread = Thread::current();
1784   ResourceMark rm(current_thread);
1785   HandleMark hm(current_thread);
1786 
1787   RegisterMap reg_map(this,
1788                       RegisterMap::UpdateMap::include,
1789                       RegisterMap::ProcessFrames::include,
1790                       RegisterMap::WalkContinuation::skip);
1791   vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
1792   int count = 0;
1793   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1794     if (f->is_java_frame()) {
1795       javaVFrame* jvf = javaVFrame::cast(f);
1796       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1797 
1798       // Print out lock information
1799       if (JavaMonitorsInStackTrace) {
1800         jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1801       }
1802     } else {
1803       // Ignore non-Java frames
1804     }
1805 
1806     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1807     count++;
1808     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1809   }
1810 }
1811 
1812 void JavaThread::print_vthread_stack_on(outputStream* st) {
1813   assert(is_vthread_mounted(), "Caller should have checked this");
1814   assert(has_last_Java_frame(), "must be");
1815 
1816   Thread* current_thread = Thread::current();
1817   ResourceMark rm(current_thread);
1818   HandleMark hm(current_thread);
1819 
1820   RegisterMap reg_map(this,
1821                       RegisterMap::UpdateMap::include,
1822                       RegisterMap::ProcessFrames::include,
1823                       RegisterMap::WalkContinuation::include);
1824   ContinuationEntry* cont_entry = last_continuation();
1825   vframe* start_vf = last_java_vframe(&reg_map);
1826   int count = 0;
1827   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1828     // Watch for end of vthread stack
1829     if (Continuation::is_continuation_enterSpecial(f->fr())) {
1830       assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1831       if (cont_entry->is_virtual_thread()) {
1832         break;
1833       }
1834       cont_entry = cont_entry->parent();
1835     }
1836     if (f->is_java_frame()) {
1837       javaVFrame* jvf = javaVFrame::cast(f);
1838       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1839 
1840       // Print out lock information
1841       if (JavaMonitorsInStackTrace) {
1842         jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1843       }
1844     } else {
1845       // Ignore non-Java frames
1846     }
1847 
1848     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1849     count++;
1850     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1851   }
1852 }
1853 
1854 void JavaThread::print_active_stack_on(outputStream* st) {
1855   if (is_vthread_mounted()) {
1856     print_vthread_stack_on(st);
1857   } else {
1858     print_stack_on(st);
1859   }
1860 }
1861 
1862 #if INCLUDE_JVMTI
1863 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1864 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1865   set_jvmti_vthread(thread_oop);
1866 
1867   // unbind current JvmtiThreadState from JavaThread
1868   JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1869 
1870   // bind new JvmtiThreadState to JavaThread
1871   JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1872 
1873   // enable interp_only_mode for virtual or carrier thread if it has pending bit
1874   JvmtiThreadState::process_pending_interp_only(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);
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(&reg_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 
2003   if (LockingMode != LM_LEGACY) {
2004     // Nothing to do. Just do some sanity check.
2005     assert(_held_monitor_count == 0, "counter should not be used");
2006     assert(_jni_monitor_count == 0, "counter should not be used");
2007     return;
2008   }
2009 
2010   assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2011   _held_monitor_count += i;
2012   if (jni) {
2013     assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2014     _jni_monitor_count += i;
2015   }
2016   assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2017          "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2018 #endif // SUPPORT_MONITOR_COUNT
2019 }
2020 
2021 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2022 // this slow-path.
2023 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2024 #ifdef SUPPORT_MONITOR_COUNT
2025 
2026   if (LockingMode != LM_LEGACY) {
2027     // Nothing to do. Just do some sanity check.
2028     assert(_held_monitor_count == 0, "counter should not be used");
2029     assert(_jni_monitor_count == 0, "counter should not be used");
2030     return;
2031   }
2032 
2033   _held_monitor_count -= i;
2034   assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2035   if (jni) {
2036     _jni_monitor_count -= i;
2037     assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2038   }
2039   // When a thread is detaching with still owned JNI monitors, the logic that releases
2040   // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2041   // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2042   // JNI count is directly set to zero.
2043   assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2044          "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2045 #endif // SUPPORT_MONITOR_COUNT
2046 }
2047 
2048 frame JavaThread::vthread_last_frame() {
2049   assert (is_vthread_mounted(), "Virtual thread not mounted");
2050   return last_frame();
2051 }
2052 
2053 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2054   const ContinuationEntry* entry = vthread_continuation();
2055   guarantee (entry != nullptr, "Not a carrier thread");
2056   frame f = entry->to_frame();
2057   if (reg_map->process_frames()) {
2058     entry->flush_stack_processing(this);
2059   }
2060   entry->update_register_map(reg_map);
2061   return f.sender(reg_map);
2062 }
2063 
2064 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2065   return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2066 }
2067 
2068 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2069   assert(reg_map != nullptr, "a map must be given");
2070   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2071     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2072   }
2073   return nullptr;
2074 }
2075 
2076 Klass* JavaThread::security_get_caller_class(int depth) {
2077   ResetNoHandleMark rnhm;
2078   HandleMark hm(Thread::current());
2079 
2080   vframeStream vfst(this);
2081   vfst.security_get_caller_frame(depth);
2082   if (!vfst.at_end()) {
2083     return vfst.method()->method_holder();
2084   }
2085   return nullptr;
2086 }
2087 
2088 // Internal convenience function for millisecond resolution sleeps.
2089 bool JavaThread::sleep(jlong millis) {
2090   jlong nanos;
2091   if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2092     // Conversion to nanos would overflow, saturate at max
2093     nanos = max_jlong;
2094   } else {
2095     nanos = millis * NANOUNITS_PER_MILLIUNIT;
2096   }
2097   return sleep_nanos(nanos);
2098 }
2099 
2100 // java.lang.Thread.sleep support
2101 // Returns true if sleep time elapsed as expected, and false
2102 // if the thread was interrupted or async exception was installed.
2103 bool JavaThread::sleep_nanos(jlong nanos) {
2104   assert(this == Thread::current(),  "thread consistency check");
2105   assert(nanos >= 0, "nanos are in range");
2106 
2107   ParkEvent * const slp = this->_SleepEvent;
2108   // Because there can be races with thread interruption sending an unpark()
2109   // to the event, we explicitly reset it here to avoid an immediate return.
2110   // The actual interrupt state will be checked before we park().
2111   slp->reset();
2112   // Thread interruption establishes a happens-before ordering in the
2113   // Java Memory Model, so we need to ensure we synchronize with the
2114   // interrupt state.
2115   OrderAccess::fence();
2116 
2117   jlong prevtime = os::javaTimeNanos();
2118 
2119   jlong nanos_remaining = nanos;
2120 
2121   for (;;) {
2122     if (has_async_exception_condition()) {
2123       return false;
2124     }
2125     // interruption has precedence over timing out
2126     if (this->is_interrupted(true)) {
2127       return false;
2128     }
2129 
2130     if (nanos_remaining <= 0) {
2131       return true;
2132     }
2133 
2134     {
2135       ThreadBlockInVM tbivm(this);
2136       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2137       slp->park_nanos(nanos_remaining);
2138     }
2139 
2140     // Update elapsed time tracking
2141     jlong newtime = os::javaTimeNanos();
2142     if (newtime - prevtime < 0) {
2143       // time moving backwards, should only happen if no monotonic clock
2144       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2145       assert(false,
2146              "unexpected time moving backwards detected in JavaThread::sleep()");
2147     } else {
2148       nanos_remaining -= (newtime - prevtime);
2149     }
2150     prevtime = newtime;
2151   }
2152 }
2153 
2154 // Last thread running calls java.lang.Shutdown.shutdown()
2155 void JavaThread::invoke_shutdown_hooks() {
2156   HandleMark hm(this);
2157 
2158   // We could get here with a pending exception, if so clear it now.
2159   if (this->has_pending_exception()) {
2160     this->clear_pending_exception();
2161   }
2162 
2163   EXCEPTION_MARK;
2164   Klass* shutdown_klass =
2165     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2166                                       THREAD);
2167   if (shutdown_klass != nullptr) {
2168     // SystemDictionary::resolve_or_null will return null if there was
2169     // an exception.  If we cannot load the Shutdown class, just don't
2170     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
2171     // won't be run.  Note that if a shutdown hook was registered,
2172     // the Shutdown class would have already been loaded
2173     // (Runtime.addShutdownHook will load it).
2174     JavaValue result(T_VOID);
2175     JavaCalls::call_static(&result,
2176                            shutdown_klass,
2177                            vmSymbols::shutdown_name(),
2178                            vmSymbols::void_method_signature(),
2179                            THREAD);
2180   }
2181   CLEAR_PENDING_EXCEPTION;
2182 }
2183 
2184 #ifndef PRODUCT
2185 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2186    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2187 }
2188 #endif
2189 
2190 // Helper function to create the java.lang.Thread object for a
2191 // VM-internal thread. The thread will have the given name, and be
2192 // a member of the "system" ThreadGroup.
2193 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2194   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2195 
2196   // Initialize thread_oop to put it into the system threadGroup.
2197   // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2198   Handle thread_group(THREAD, Universe::system_thread_group());
2199   Handle thread_oop =
2200     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2201                                       vmSymbols::threadgroup_string_void_signature(),
2202                                       thread_group,
2203                                       string,
2204                                       CHECK_NH);
2205 
2206   return thread_oop;
2207 }
2208 
2209 // Starts the target JavaThread as a daemon of the given priority, and
2210 // bound to the given java.lang.Thread instance.
2211 // The Threads_lock is held for the duration.
2212 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2213                                        Handle thread_oop, ThreadPriority prio) {
2214 
2215   assert(target->osthread() != nullptr, "target thread is not properly initialized");
2216 
2217   MutexLocker mu(current, Threads_lock);
2218 
2219   // Initialize the fields of the thread_oop first.
2220   if (prio != NoPriority) {
2221     java_lang_Thread::set_priority(thread_oop(), prio);
2222     // Note: we don't call os::set_priority here. Possibly we should,
2223     // else all threads should call it themselves when they first run.
2224   }
2225 
2226   java_lang_Thread::set_daemon(thread_oop());
2227 
2228   // Now bind the thread_oop to the target JavaThread.
2229   target->set_threadOopHandles(thread_oop());
2230   target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2231 
2232   Threads::add(target); // target is now visible for safepoint/handshake
2233   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2234   // on a ThreadsList. We don't want to wait for the release when the
2235   // Theads_lock is dropped when the 'mu' destructor is run since the
2236   // JavaThread* is already visible to JVM/TI via the ThreadsList.
2237 
2238   assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2239   java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2240   Thread::start(target);
2241 }
2242 
2243 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2244   // At this point it may be possible that no osthread was created for the
2245   // JavaThread due to lack of resources. However, since this must work
2246   // for critical system threads just check and abort if this fails.
2247   if (thread->osthread() == nullptr) {
2248     // This isn't really an OOM condition, but historically this is what
2249     // we report.
2250     vm_exit_during_initialization("java.lang.OutOfMemoryError",
2251                                   os::native_thread_creation_failed_msg());
2252   }
2253 }
2254 
2255 void JavaThread::pretouch_stack() {
2256   // Given an established java thread stack with usable area followed by
2257   // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2258   // from the current frame down to the start of the shadow zone.
2259   const address end = _stack_overflow_state.shadow_zone_safe_limit();
2260   if (is_in_full_stack(end)) {
2261     char* p1 = (char*) alloca(1);
2262     address here = (address) &p1;
2263     if (is_in_full_stack(here) && here > end) {
2264       size_t to_alloc = here - end;
2265       char* p2 = (char*) alloca(to_alloc);
2266       log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2267                             (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2268       os::pretouch_memory(p2, p2 + to_alloc,
2269                           NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2270     }
2271   }
2272 }
2273 
2274 // Deferred OopHandle release support.
2275 
2276 class OopHandleList : public CHeapObj<mtInternal> {
2277   static const int _count = 4;
2278   OopHandle _handles[_count];
2279   OopHandleList* _next;
2280   int _index;
2281  public:
2282   OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2283   void add(OopHandle h) {
2284     assert(_index < _count, "too many additions");
2285     _handles[_index++] = h;
2286   }
2287   ~OopHandleList() {
2288     assert(_index == _count, "usage error");
2289     for (int i = 0; i < _index; i++) {
2290       _handles[i].release(JavaThread::thread_oop_storage());
2291     }
2292   }
2293   OopHandleList* next() const { return _next; }
2294 };
2295 
2296 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2297 
2298 // Called by the ServiceThread to do the work of releasing
2299 // the OopHandles.
2300 void JavaThread::release_oop_handles() {
2301   OopHandleList* list;
2302   {
2303     MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2304     list = _oop_handle_list;
2305     _oop_handle_list = nullptr;
2306   }
2307   assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2308 
2309   while (list != nullptr) {
2310     OopHandleList* l = list;
2311     list = l->next();
2312     delete l;
2313   }
2314 }
2315 
2316 // Add our OopHandles for later release.
2317 void JavaThread::add_oop_handles_for_release() {
2318   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2319   OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2320   new_head->add(_threadObj);
2321   new_head->add(_vthread);
2322   new_head->add(_jvmti_vthread);
2323   new_head->add(_scopedValueCache);
2324   _oop_handle_list = new_head;
2325   Service_lock->notify_all();
2326 }
2327 
2328 #if INCLUDE_JFR
2329 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2330   assert(result != freeze_ok, "sanity check");
2331   _last_freeze_fail_result = result;
2332   _last_freeze_fail_time = Ticks::now();
2333 }
2334 
2335 // Post jdk.VirtualThreadPinned event
2336 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2337   assert(result != freeze_ok, "sanity check");
2338   if (event->should_commit()) {
2339     char reason[256];
2340     if (class_to_be_initialized() != nullptr) {
2341       ResourceMark rm(this);
2342       jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2343                    class_to_be_initialized()->external_name());
2344       event->set_pinnedReason(reason);
2345     } else if (class_being_initialized() != nullptr) {
2346       ResourceMark rm(this);
2347       jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2348                    class_being_initialized()->external_name());
2349       event->set_pinnedReason(reason);
2350     } else if (result == freeze_pinned_native) {
2351       event->set_pinnedReason("Native or VM frame on stack");
2352     } else {
2353       jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2354       event->set_pinnedReason(reason);
2355     }
2356     event->set_blockingOperation(op);
2357     event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2358     event->commit();
2359   }
2360 }
2361 #endif