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/compilerThread.hpp"
  36 #include "compiler/compileTask.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/atomicAccess.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/vframe_hp.hpp"
  92 #include "runtime/vframeArray.hpp"
  93 #include "runtime/vmOperations.hpp"
  94 #include "runtime/vmThread.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 
 480   _jni_active_critical(0),
 481   _pending_jni_exception_check_fn(nullptr),
 482   _depth_first_number(0),
 483 
 484   // JVMTI PopFrame support
 485   _popframe_condition(popframe_inactive),
 486   _frames_to_pop_failed_realloc(0),
 487 
 488   _cont_entry(nullptr),
 489   _cont_fastpath(nullptr),
 490   _cont_fastpath_thread_state(1),
 491   _unlocked_inflated_monitor(nullptr),
 492 
 493   _can_call_java(true),
 494 
 495   _preempt_alternate_return(nullptr),
 496   _preemption_cancelled(false),
 497   _pending_interrupted_exception(false),
 498 
 499   _handshake(this),
 500   _suspend_resume_manager(this, &_handshake._lock),
 501 
 502   _popframe_preserved_args(nullptr),
 503   _popframe_preserved_args_size(0),
 504 
 505   _jvmti_thread_state(nullptr),
 506   _interp_only_mode(0),
 507   _should_post_on_exceptions_flag(JNI_FALSE),
 508   _thread_stat(new ThreadStatistics()),
 509 
 510   _parker(),
 511 
 512   _class_to_be_initialized(nullptr),
 513   _class_being_initialized(nullptr),
 514 
 515   _SleepEvent(ParkEvent::Allocate(this)),
 516 
 517 #if INCLUDE_JFR
 518   _last_freeze_fail_result(freeze_ok),
 519 #endif
 520 
 521   _lock_stack(this),
 522   _om_cache(this) {
 523   set_jni_functions(jni_functions());
 524 
 525 #if INCLUDE_JVMCI
 526   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
 527   if (JVMCICounterSize > 0) {
 528     resize_counters(0, (int) JVMCICounterSize);
 529   }
 530 #endif // INCLUDE_JVMCI
 531 
 532   // Setup safepoint state info for this thread
 533   ThreadSafepointState::create(this);
 534 
 535   SafepointMechanism::initialize_header(this);
 536 
 537   set_requires_cross_modify_fence(false);
 538 
 539   pd_initialize();
 540   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
 541 }
 542 
 543 JavaThread* JavaThread::create_attaching_thread() {
 544   JavaThread* jt = new JavaThread();
 545   jt->_jni_attach_state = _attaching_via_jni;
 546   return jt;
 547 }
 548 
 549 // interrupt support
 550 
 551 void JavaThread::interrupt() {
 552   // All callers should have 'this' thread protected by a
 553   // ThreadsListHandle so that it cannot terminate and deallocate
 554   // itself.
 555   DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
 556 
 557   // For Windows _interrupt_event
 558   WINDOWS_ONLY(osthread()->set_interrupted(true);)
 559 
 560   // For Thread.sleep
 561   _SleepEvent->unpark();
 562 
 563   // For JSR166 LockSupport.park
 564   parker()->unpark();
 565 
 566   // For ObjectMonitor and JvmtiRawMonitor
 567   _ParkEvent->unpark();
 568 }
 569 
 570 bool JavaThread::is_interrupted(bool clear_interrupted) {
 571   DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
 572 
 573   if (_threadObj.peek() == nullptr) {
 574     // If there is no j.l.Thread then it is impossible to have
 575     // been interrupted. We can find null during VM initialization
 576     // or when a JNI thread is still in the process of attaching.
 577     // In such cases this must be the current thread.
 578     assert(this == Thread::current(), "invariant");
 579     return false;
 580   }
 581 
 582   bool interrupted = java_lang_Thread::interrupted(threadObj());
 583 
 584   // NOTE that since there is no "lock" around the interrupt and
 585   // is_interrupted operations, there is the possibility that the
 586   // interrupted flag will be "false" but that the
 587   // low-level events will be in the signaled state. This is
 588   // intentional. The effect of this is that Object.wait() and
 589   // LockSupport.park() will appear to have a spurious wakeup, which
 590   // is allowed and not harmful, and the possibility is so rare that
 591   // it is not worth the added complexity to add yet another lock.
 592   // For the sleep event an explicit reset is performed on entry
 593   // to JavaThread::sleep, so there is no early return. It has also been
 594   // recommended not to put the interrupted flag into the "event"
 595   // structure because it hides the issue.
 596   // Also, because there is no lock, we must only clear the interrupt
 597   // state if we are going to report that we were interrupted; otherwise
 598   // an interrupt that happens just after we read the field would be lost.
 599   if (interrupted && clear_interrupted) {
 600     assert(this == Thread::current(), "only the current thread can clear");
 601     java_lang_Thread::set_interrupted(threadObj(), false);
 602     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 603   }
 604   return interrupted;
 605 }
 606 
 607 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
 608 // the Java code in Object::wait which are not present in RawMonitorWait.
 609 bool JavaThread::get_and_clear_interrupted() {
 610   if (!is_interrupted(false)) {
 611     return false;
 612   }
 613   oop thread_oop = vthread_or_thread();
 614   bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
 615 
 616   if (!is_virtual) {
 617     return is_interrupted(true);
 618   }
 619   // Virtual thread: clear interrupt status for both virtual and
 620   // carrier threads under the interruptLock protection.
 621   JavaThread* current = JavaThread::current();
 622   HandleMark hm(current);
 623   Handle thread_h(current, thread_oop);
 624   ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
 625 
 626   // re-check the interrupt status under the interruptLock protection
 627   bool interrupted = java_lang_Thread::interrupted(thread_h());
 628 
 629   if (interrupted) {
 630     assert(this == Thread::current(), "only the current thread can clear");
 631     java_lang_Thread::set_interrupted(thread_h(), false);  // clear for virtual
 632     java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
 633     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 634   }
 635   return interrupted;
 636 }
 637 
 638 void JavaThread::block_if_vm_exited() {
 639   if (_terminated == _vm_exited) {
 640     // _vm_exited is set at safepoint, and Threads_lock is never released
 641     // so we will block here forever.
 642     // Here we can be doing a jump from a safe state to an unsafe state without
 643     // proper transition, but it happens after the final safepoint has begun so
 644     // this jump won't cause any safepoint problems.
 645     set_thread_state(_thread_in_vm);
 646     Threads_lock->lock();
 647     ShouldNotReachHere();
 648   }
 649 }
 650 
 651 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
 652   set_entry_point(entry_point);
 653   // Create the native thread itself.
 654   // %note runtime_23
 655   os::ThreadType thr_type = os::java_thread;
 656   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
 657                                                             os::java_thread;
 658   os::create_thread(this, thr_type, stack_sz);
 659   // The _osthread may be null here because we ran out of memory (too many threads active).
 660   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
 661   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
 662   // the exception consists of creating the exception object & initializing it, initialization
 663   // will leave the VM via a JavaCall and then all locks must be unlocked).
 664   //
 665   // The thread is still suspended when we reach here. Thread must be explicit started
 666   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
 667   // by calling Threads:add. The reason why this is not done here, is because the thread
 668   // object must be fully initialized (take a look at JVM_Start)
 669 }
 670 
 671 JavaThread::~JavaThread() {
 672 
 673   // Enqueue OopHandles for release by the service thread.
 674   add_oop_handles_for_release();
 675 
 676   // Return the sleep event to the free list
 677   ParkEvent::Release(_SleepEvent);
 678   _SleepEvent = nullptr;
 679 
 680   // Free any remaining  previous UnrollBlock
 681   vframeArray* old_array = vframe_array_last();
 682 
 683   if (old_array != nullptr) {
 684     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
 685     old_array->set_unroll_block(nullptr);
 686     delete old_info;
 687     delete old_array;
 688   }
 689 
 690   JvmtiDeferredUpdates* updates = deferred_updates();
 691   if (updates != nullptr) {
 692     // This can only happen if thread is destroyed before deoptimization occurs.
 693     assert(updates->count() > 0, "Updates holder not deleted");
 694     // free deferred updates.
 695     delete updates;
 696     set_deferred_updates(nullptr);
 697   }
 698 
 699   // All Java related clean up happens in exit
 700   ThreadSafepointState::destroy(this);
 701   if (_thread_stat != nullptr) delete _thread_stat;
 702 
 703 #if INCLUDE_JVMCI
 704   if (JVMCICounterSize > 0) {
 705     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
 706   }
 707 #endif // INCLUDE_JVMCI
 708 }
 709 
 710 
 711 // First JavaThread specific code executed by a new Java thread.
 712 void JavaThread::pre_run() {
 713   // empty - see comments in run()
 714 }
 715 
 716 // The main routine called by a new Java thread. This isn't overridden
 717 // by subclasses, instead different subclasses define a different "entry_point"
 718 // which defines the actual logic for that kind of thread.
 719 void JavaThread::run() {
 720   // initialize thread-local alloc buffer related fields
 721   initialize_tlab();
 722 
 723   _stack_overflow_state.create_stack_guard_pages();
 724 
 725   cache_global_variables();
 726 
 727   // Thread is now sufficiently initialized to be handled by the safepoint code as being
 728   // in the VM. Change thread state from _thread_new to _thread_in_vm
 729   assert(this->thread_state() == _thread_new, "wrong thread state");
 730   set_thread_state(_thread_in_vm);
 731 
 732   // Before a thread is on the threads list it is always safe, so after leaving the
 733   // _thread_new we should emit a instruction barrier. The distance to modified code
 734   // from here is probably far enough, but this is consistent and safe.
 735   OrderAccess::cross_modify_fence();
 736 
 737   assert(JavaThread::current() == this, "sanity check");
 738   assert(!Thread::current()->owns_locks(), "sanity check");
 739 
 740   JFR_ONLY(Jfr::on_thread_start(this);)
 741 
 742   DTRACE_THREAD_PROBE(start, this);
 743 
 744   // This operation might block. We call that after all safepoint checks for a new thread has
 745   // been completed.
 746   set_active_handles(JNIHandleBlock::allocate_block());
 747 
 748   if (JvmtiExport::should_post_thread_life()) {
 749     JvmtiExport::post_thread_start(this);
 750 
 751   }
 752 
 753   if (AlwaysPreTouchStacks) {
 754     pretouch_stack();
 755   }
 756 
 757   // We call another function to do the rest so we are sure that the stack addresses used
 758   // from there will be lower than the stack base just computed.
 759   thread_main_inner();
 760 }
 761 
 762 void JavaThread::thread_main_inner() {
 763   assert(JavaThread::current() == this, "sanity check");
 764   assert(_threadObj.peek() != nullptr, "just checking");
 765 
 766   // Execute thread entry point unless this thread has a pending exception.
 767   // Note: Due to JVMTI StopThread we can have pending exceptions already!
 768   if (!this->has_pending_exception()) {
 769     {
 770       ResourceMark rm(this);
 771       this->set_native_thread_name(this->name());
 772     }
 773     HandleMark hm(this);
 774     this->entry_point()(this, this);
 775   }
 776 
 777   DTRACE_THREAD_PROBE(stop, this);
 778 
 779   // Cleanup is handled in post_run()
 780 }
 781 
 782 // Shared teardown for all JavaThreads
 783 void JavaThread::post_run() {
 784   this->exit(false);
 785   this->unregister_thread_stack_with_NMT();
 786   // Defer deletion to here to ensure 'this' is still referenceable in call_run
 787   // for any shared tear-down.
 788   this->smr_delete();
 789 }
 790 
 791 static void ensure_join(JavaThread* thread) {
 792   // We do not need to grab the Threads_lock, since we are operating on ourself.
 793   Handle threadObj(thread, thread->threadObj());
 794   assert(threadObj.not_null(), "java thread object must exist");
 795   ObjectLocker lock(threadObj, thread);
 796   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
 797   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
 798   // Clear the native thread instance - this makes isAlive return false and allows the join()
 799   // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
 800   // requirements.
 801   assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
 802   java_lang_Thread::release_set_thread(threadObj(), nullptr);
 803   lock.notify_all(thread);
 804   // Ignore pending exception, since we are exiting anyway
 805   thread->clear_pending_exception();
 806 }
 807 
 808 static bool is_daemon(oop threadObj) {
 809   return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
 810 }
 811 
 812 // For any new cleanup additions, please check to see if they need to be applied to
 813 // cleanup_failed_attach_current_thread as well.
 814 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
 815   assert(this == JavaThread::current(), "thread consistency check");
 816   assert(!is_exiting(), "should not be exiting or terminated already");
 817 
 818   elapsedTimer _timer_exit_phase1;
 819   elapsedTimer _timer_exit_phase2;
 820   elapsedTimer _timer_exit_phase3;
 821   elapsedTimer _timer_exit_phase4;
 822 
 823   om_clear_monitor_cache();
 824 
 825   if (log_is_enabled(Debug, os, thread, timer)) {
 826     _timer_exit_phase1.start();
 827   }
 828 
 829   HandleMark hm(this);
 830   Handle uncaught_exception(this, this->pending_exception());
 831   this->clear_pending_exception();
 832   Handle threadObj(this, this->threadObj());
 833   assert(threadObj.not_null(), "Java thread object should be created");
 834 
 835   if (!destroy_vm) {
 836     if (uncaught_exception.not_null()) {
 837       EXCEPTION_MARK;
 838       // Call method Thread.dispatchUncaughtException().
 839       Klass* thread_klass = vmClasses::Thread_klass();
 840       JavaValue result(T_VOID);
 841       JavaCalls::call_virtual(&result,
 842                               threadObj, thread_klass,
 843                               vmSymbols::dispatchUncaughtException_name(),
 844                               vmSymbols::throwable_void_signature(),
 845                               uncaught_exception,
 846                               THREAD);
 847       if (HAS_PENDING_EXCEPTION) {
 848         ResourceMark rm(this);
 849         jio_fprintf(defaultStream::error_stream(),
 850                     "\nException: %s thrown from the UncaughtExceptionHandler"
 851                     " in thread \"%s\"\n",
 852                     pending_exception()->klass()->external_name(),
 853                     name());
 854         CLEAR_PENDING_EXCEPTION;
 855       }
 856     }
 857 
 858     if (!is_Compiler_thread()) {
 859       // We have finished executing user-defined Java code and now have to do the
 860       // implementation specific clean-up by calling Thread.exit(). We prevent any
 861       // asynchronous exceptions from being delivered while in Thread.exit()
 862       // to ensure the clean-up is not corrupted.
 863       NoAsyncExceptionDeliveryMark _no_async(this);
 864 
 865       EXCEPTION_MARK;
 866       JavaValue result(T_VOID);
 867       Klass* thread_klass = vmClasses::Thread_klass();
 868       JavaCalls::call_virtual(&result,
 869                               threadObj, thread_klass,
 870                               vmSymbols::exit_method_name(),
 871                               vmSymbols::void_method_signature(),
 872                               THREAD);
 873       CLEAR_PENDING_EXCEPTION;
 874     }
 875 
 876     // notify JVMTI
 877     if (JvmtiExport::should_post_thread_life()) {
 878       JvmtiExport::post_thread_end(this);
 879     }
 880   } else {
 881     // before_exit() has already posted JVMTI THREAD_END events
 882   }
 883 
 884   // Cleanup any pending async exception now since we cannot access oops after
 885   // BarrierSet::barrier_set()->on_thread_detach() has been executed.
 886   if (has_async_exception_condition()) {
 887     handshake_state()->clean_async_exception_operation();
 888   }
 889 
 890   // The careful dance between thread suspension and exit is handled here.
 891   // Since we are in thread_in_vm state and suspension is done with handshakes,
 892   // we can just put in the exiting state and it will be correctly handled.
 893   // Also, no more async exceptions will be added to the queue after this point.
 894   set_terminated(_thread_exiting);
 895   ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
 896 
 897   if (log_is_enabled(Debug, os, thread, timer)) {
 898     _timer_exit_phase1.stop();
 899     _timer_exit_phase2.start();
 900   }
 901 
 902   // Capture daemon status before the thread is marked as terminated.
 903   bool daemon = is_daemon(threadObj());
 904 
 905   // Notify waiters on thread object. This has to be done after exit() is called
 906   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
 907   // group should have the destroyed bit set before waiters are notified).
 908   ensure_join(this);
 909   assert(!this->has_pending_exception(), "ensure_join should have cleared");
 910 
 911   if (log_is_enabled(Debug, os, thread, timer)) {
 912     _timer_exit_phase2.stop();
 913     _timer_exit_phase3.start();
 914   }
 915   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
 916   // held by this thread must be released. The spec does not distinguish
 917   // between JNI-acquired and regular Java monitors. We can only see
 918   // regular Java monitors here if monitor enter-exit matching is broken.
 919   //
 920   // ensure_join() ignores IllegalThreadStateExceptions, and so does
 921   // ObjectSynchronizer::release_monitors_owned_by_thread().
 922   if (exit_type == jni_detach) {
 923     // Sanity check even though JNI DetachCurrentThread() would have
 924     // returned JNI_ERR if there was a Java frame. JavaThread exit
 925     // should be done executing Java code by the time we get here.
 926     assert(!this->has_last_Java_frame(),
 927            "should not have a Java frame when detaching or exiting");
 928     ObjectSynchronizer::release_monitors_owned_by_thread(this);
 929     assert(!this->has_pending_exception(), "release_monitors should have cleared");
 930   }
 931 
 932   // These things needs to be done while we are still a Java Thread. Make sure that thread
 933   // is in a consistent state, in case GC happens
 934   JFR_ONLY(Jfr::on_thread_exit(this);)
 935 
 936   if (active_handles() != nullptr) {
 937     JNIHandleBlock* block = active_handles();
 938     set_active_handles(nullptr);
 939     JNIHandleBlock::release_block(block);
 940   }
 941 
 942   if (free_handle_block() != nullptr) {
 943     JNIHandleBlock* block = free_handle_block();
 944     set_free_handle_block(nullptr);
 945     JNIHandleBlock::release_block(block);
 946   }
 947 
 948   // These have to be removed while this is still a valid thread.
 949   _stack_overflow_state.remove_stack_guard_pages();
 950 
 951   if (UseTLAB) {
 952     retire_tlab();
 953   }
 954 
 955   if (JvmtiEnv::environments_might_exist()) {
 956     JvmtiExport::cleanup_thread(this);
 957   }
 958 
 959   // We need to cache the thread name for logging purposes below as once
 960   // we have called on_thread_detach this thread must not access any oops.
 961   char* thread_name = nullptr;
 962   if (log_is_enabled(Debug, os, thread, timer) || (CountBytecodesPerThread && log_is_enabled(Info, init))) {
 963     ResourceMark rm(this);
 964     thread_name = os::strdup(name());
 965   }
 966 
 967   if (log_is_enabled(Info, os, thread)) {
 968     ResourceMark rm(this);
 969     log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
 970                          exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
 971                          name(), os::current_thread_id());
 972   }
 973 
 974   if (log_is_enabled(Debug, os, thread, timer)) {
 975     _timer_exit_phase3.stop();
 976     _timer_exit_phase4.start();
 977   }
 978 
 979 #if INCLUDE_JVMCI
 980   if (JVMCICounterSize > 0) {
 981     if (jvmci_counters_include(this)) {
 982       for (int i = 0; i < JVMCICounterSize; i++) {
 983         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
 984       }
 985     }
 986   }
 987 #endif // INCLUDE_JVMCI
 988 
 989   if (bc_counter_value() > 0) {
 990     log_info(init)("Thread '%s': " JLONG_FORMAT " bytecodes executed (during clinit: " JLONG_FORMAT ")",
 991                    thread_name, bc_counter_value(), clinit_bc_counter_value());
 992   }
 993 
 994   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
 995   // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
 996   Threads::remove(this, daemon);
 997 
 998   if (log_is_enabled(Debug, os, thread, timer)) {
 999     _timer_exit_phase4.stop();
1000     log_debug(os, thread, timer)("name='%s'"
1001                                  ", exit-phase1=" JLONG_FORMAT
1002                                  ", exit-phase2=" JLONG_FORMAT
1003                                  ", exit-phase3=" JLONG_FORMAT
1004                                  ", exit-phase4=" JLONG_FORMAT,
1005                                  thread_name,
1006                                  _timer_exit_phase1.milliseconds(),
1007                                  _timer_exit_phase2.milliseconds(),
1008                                  _timer_exit_phase3.milliseconds(),
1009                                  _timer_exit_phase4.milliseconds());
1010     os::free(thread_name);
1011   }
1012 }
1013 
1014 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1015   if (active_handles() != nullptr) {
1016     JNIHandleBlock* block = active_handles();
1017     set_active_handles(nullptr);
1018     JNIHandleBlock::release_block(block);
1019   }
1020 
1021   if (free_handle_block() != nullptr) {
1022     JNIHandleBlock* block = free_handle_block();
1023     set_free_handle_block(nullptr);
1024     JNIHandleBlock::release_block(block);
1025   }
1026 
1027   // These have to be removed while this is still a valid thread.
1028   _stack_overflow_state.remove_stack_guard_pages();
1029 
1030   if (UseTLAB) {
1031     retire_tlab();
1032   }
1033 
1034   Threads::remove(this, is_daemon);
1035 }
1036 
1037 JavaThread* JavaThread::active() {
1038   Thread* thread = Thread::current();
1039   if (thread->is_Java_thread()) {
1040     return JavaThread::cast(thread);
1041   } else {
1042     assert(thread->is_VM_thread(), "this must be a vm thread");
1043     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1044     JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1045     return ret;
1046   }
1047 }
1048 
1049 oop JavaThread::exception_oop() const {
1050   return AtomicAccess::load(&_exception_oop);
1051 }
1052 
1053 void JavaThread::set_exception_oop(oop o) {
1054   AtomicAccess::store(&_exception_oop, o);
1055 }
1056 
1057 void JavaThread::handle_special_runtime_exit_condition() {
1058   if (is_obj_deopt_suspend()) {
1059     frame_anchor()->make_walkable();
1060     wait_for_object_deoptimization();
1061   }
1062 }
1063 
1064 
1065 // Asynchronous exceptions support
1066 //
1067 void JavaThread::handle_async_exception(oop java_throwable) {
1068   assert(java_throwable != nullptr, "should have an _async_exception to throw");
1069   assert(!is_at_poll_safepoint(), "should have never called this method");
1070 
1071   if (has_last_Java_frame()) {
1072     frame f = last_frame();
1073     if (f.is_runtime_frame()) {
1074       // If the topmost frame is a runtime stub, then we are calling into
1075       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1076       // must deoptimize the caller before continuing, as the compiled exception
1077       // handler table may not be valid.
1078       RegisterMap reg_map(this,
1079                           RegisterMap::UpdateMap::skip,
1080                           RegisterMap::ProcessFrames::include,
1081                           RegisterMap::WalkContinuation::skip);
1082       frame compiled_frame = f.sender(&reg_map);
1083       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1084         Deoptimization::deoptimize(this, compiled_frame);
1085       }
1086     }
1087   }
1088 
1089   // We cannot call Exceptions::_throw(...) here because we cannot block
1090   set_pending_exception(java_throwable, __FILE__, __LINE__);
1091 
1092   clear_scopedValueBindings();
1093 
1094   LogTarget(Info, exceptions) lt;
1095   if (lt.is_enabled()) {
1096     ResourceMark rm;
1097     LogStream ls(lt);
1098     ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1099     if (has_last_Java_frame()) {
1100       frame f = last_frame();
1101       ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1102     }
1103     ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1104   }
1105 }
1106 
1107 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1108   // Do not throw asynchronous exceptions against the compiler thread
1109   // or if the thread is already exiting.
1110   if (!can_call_java() || is_exiting()) {
1111     delete aehc;
1112     return;
1113   }
1114 
1115   oop exception = aehc->exception();
1116   Handshake::execute(aehc, this);  // Install asynchronous handshake
1117 
1118   ResourceMark rm;
1119   if (log_is_enabled(Info, exceptions)) {
1120     log_info(exceptions)("Pending Async. exception installed of type: %s",
1121                          exception->klass()->external_name());
1122   }
1123   // for AbortVMOnException flag
1124   Exceptions::debug_check_abort(exception->klass()->external_name());
1125 
1126   oop vt_oop = vthread();
1127   if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1128     // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1129     this->interrupt();
1130   }
1131 }
1132 
1133 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1134   AsyncExceptionHandshakeClosure* _aehc;
1135 public:
1136   InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1137     HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1138   ~InstallAsyncExceptionHandshakeClosure() {
1139     // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1140     delete _aehc;
1141   }
1142   void do_thread(Thread* thr) {
1143     JavaThread* target = JavaThread::cast(thr);
1144     target->install_async_exception(_aehc);
1145     _aehc = nullptr;
1146   }
1147 };
1148 
1149 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1150   OopHandle e(Universe::vm_global(), java_throwable);
1151   InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1152   Handshake::execute(&iaeh, target);
1153 }
1154 
1155 #if INCLUDE_JVMTI
1156 void JavaThread::set_is_in_VTMS_transition(bool val) {
1157   assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1158   _is_in_VTMS_transition = val;
1159 }
1160 
1161 #ifdef ASSERT
1162 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1163   _is_VTMS_transition_disabler = val;
1164 }
1165 #endif
1166 #endif
1167 
1168 // External suspension mechanism.
1169 //
1170 // Guarantees on return (for a valid target thread):
1171 //   - Target thread will not execute any new bytecode.
1172 //   - Target thread will not enter any new monitors.
1173 //
1174 bool JavaThread::java_suspend(bool register_vthread_SR) {
1175 #if INCLUDE_JVMTI
1176   // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1177   assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1178   assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1179 #endif
1180 
1181   guarantee(Thread::is_JavaThread_protected(/* target */ this),
1182             "target JavaThread is not protected in calling context.");
1183   return this->suspend_resume_manager()->suspend(register_vthread_SR);
1184 }
1185 
1186 bool JavaThread::java_resume(bool register_vthread_SR) {
1187   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1188             "missing ThreadsListHandle in calling context.");
1189   return this->suspend_resume_manager()->resume(register_vthread_SR);
1190 }
1191 
1192 // Wait for another thread to perform object reallocation and relocking on behalf of
1193 // this thread. The current thread is required to change to _thread_blocked in order
1194 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1195 // handshake safe, the other thread can complete the handshake used to synchronize
1196 // with this thread and then perform the reallocation and relocking.
1197 // See EscapeBarrier::sync_and_suspend_*()
1198 
1199 void JavaThread::wait_for_object_deoptimization() {
1200   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1201   assert(this == Thread::current(), "invariant");
1202 
1203   bool spin_wait = os::is_MP();
1204   do {
1205     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1206     // Wait for object deoptimization if requested.
1207     if (spin_wait) {
1208       // A single deoptimization is typically very short. Microbenchmarks
1209       // showed 5% better performance when spinning.
1210       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1211       SpinYield spin(spin_limit);
1212       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1213         spin.wait();
1214       }
1215       // Spin just once
1216       spin_wait = false;
1217     } else {
1218       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1219       if (is_obj_deopt_suspend()) {
1220         ml.wait();
1221       }
1222     }
1223     // A handshake for obj. deoptimization suspend could have been processed so
1224     // we must check after processing.
1225   } while (is_obj_deopt_suspend());
1226 }
1227 
1228 #ifdef ASSERT
1229 // Verify the JavaThread has not yet been published in the Threads::list, and
1230 // hence doesn't need protection from concurrent access at this stage.
1231 void JavaThread::verify_not_published() {
1232   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1233   // since an unpublished JavaThread doesn't participate in the
1234   // Thread-SMR protocol for keeping a ThreadsList alive.
1235   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1236 }
1237 #endif
1238 
1239 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1240 // pending, when _suspend_flags is non-zero or when we need to process a stack
1241 // watermark. Also check for pending async exceptions (except unsafe access error).
1242 // Note only the native==>Java barriers can call this function when thread state
1243 // is _thread_in_native_trans.
1244 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1245   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1246   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1247 
1248   thread->set_thread_state(_thread_in_vm);
1249 
1250   // Enable WXWrite: called directly from interpreter native wrapper.
1251   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1252 
1253   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1254 
1255   // After returning from native, it could be that the stack frames are not
1256   // yet safe to use. We catch such situations in the subsequent stack watermark
1257   // barrier, which will trap unsafe stack frames.
1258   StackWatermarkSet::before_unwind(thread);
1259 }
1260 
1261 #ifndef PRODUCT
1262 // Deoptimization
1263 // Function for testing deoptimization
1264 void JavaThread::deoptimize() {
1265   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1266   bool deopt = false;           // Dump stack only if a deopt actually happens.
1267   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1268   // Iterate over all frames in the thread and deoptimize
1269   for (; !fst.is_done(); fst.next()) {
1270     if (fst.current()->can_be_deoptimized()) {
1271 
1272       if (only_at) {
1273         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1274         // consists of comma or carriage return separated numbers so
1275         // search for the current bci in that string.
1276         address    pc = fst.current()->pc();
1277         nmethod*   nm = fst.current()->cb()->as_nmethod();
1278         ScopeDesc* sd = nm->scope_desc_at(pc);
1279         char buffer[8];
1280         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1281         size_t len = strlen(buffer);
1282         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1283         while (found != nullptr) {
1284           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1285               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1286             // Check that the bci found is bracketed by terminators.
1287             break;
1288           }
1289           found = strstr(found + 1, buffer);
1290         }
1291         if (!found) {
1292           continue;
1293         }
1294       }
1295 
1296       if (DebugDeoptimization && !deopt) {
1297         deopt = true; // One-time only print before deopt
1298         tty->print_cr("[BEFORE Deoptimization]");
1299         trace_frames();
1300         trace_stack();
1301       }
1302       Deoptimization::deoptimize(this, *fst.current());
1303     }
1304   }
1305 
1306   if (DebugDeoptimization && deopt) {
1307     tty->print_cr("[AFTER Deoptimization]");
1308     trace_frames();
1309   }
1310 }
1311 
1312 
1313 // Make zombies
1314 void JavaThread::make_zombies() {
1315   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1316     if (fst.current()->can_be_deoptimized()) {
1317       // it is a Java nmethod
1318       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1319       assert(nm != nullptr, "did not find nmethod");
1320       nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1321     }
1322   }
1323 }
1324 #endif // PRODUCT
1325 
1326 
1327 void JavaThread::deoptimize_marked_methods() {
1328   if (!has_last_Java_frame()) return;
1329   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1330   for (; !fst.is_done(); fst.next()) {
1331     if (fst.current()->should_be_deoptimized()) {
1332       Deoptimization::deoptimize(this, *fst.current());
1333     }
1334   }
1335 }
1336 
1337 #ifdef ASSERT
1338 void JavaThread::verify_frame_info() {
1339   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1340          (has_last_Java_frame() && java_call_counter() > 0),
1341          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1342          has_last_Java_frame() ? "true" : "false", java_call_counter());
1343 }
1344 #endif
1345 
1346 // Push on a new block of JNI handles.
1347 void JavaThread::push_jni_handle_block() {
1348   // Allocate a new block for JNI handles.
1349   // Inlined code from jni_PushLocalFrame()
1350   JNIHandleBlock* old_handles = active_handles();
1351   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1352   assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1353   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1354   set_active_handles(new_handles);
1355 }
1356 
1357 // Pop off the current block of JNI handles.
1358 void JavaThread::pop_jni_handle_block() {
1359   // Release our JNI handle block
1360   JNIHandleBlock* old_handles = active_handles();
1361   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1362   assert(new_handles != nullptr, "should never set active handles to null");
1363   set_active_handles(new_handles);
1364   old_handles->set_pop_frame_link(nullptr);
1365   JNIHandleBlock::release_block(old_handles, this);
1366 }
1367 
1368 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1369   // Verify that the deferred card marks have been flushed.
1370   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1371 
1372   // Traverse the GCHandles
1373   Thread::oops_do_no_frames(f, cf);
1374 
1375   if (active_handles() != nullptr) {
1376     active_handles()->oops_do(f);
1377   }
1378 
1379   DEBUG_ONLY(verify_frame_info();)
1380 
1381   assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1382   // If we have deferred set_locals there might be oops waiting to be
1383   // written
1384   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1385   if (list != nullptr) {
1386     for (int i = 0; i < list->length(); i++) {
1387       list->at(i)->oops_do(f);
1388     }
1389   }
1390 
1391   // Traverse instance variables at the end since the GC may be moving things
1392   // around using this function
1393   f->do_oop((oop*) &_vm_result_oop);
1394   f->do_oop((oop*) &_exception_oop);
1395 #if INCLUDE_JVMCI
1396   f->do_oop((oop*) &_jvmci_reserved_oop0);
1397 
1398   if (_live_nmethod != nullptr && cf != nullptr) {
1399     cf->do_nmethod(_live_nmethod);
1400   }
1401 #endif
1402 
1403   if (jvmti_thread_state() != nullptr) {
1404     jvmti_thread_state()->oops_do(f, cf);
1405   }
1406 
1407   // The continuation oops are really on the stack. But there is typically at most
1408   // one of those per thread, so we handle them here in the oops_do_no_frames part
1409   // so that we don't have to sprinkle as many stack watermark checks where these
1410   // oops are used. We just need to make sure the thread has started processing.
1411   ContinuationEntry* entry = _cont_entry;
1412   while (entry != nullptr) {
1413     f->do_oop((oop*)entry->cont_addr());
1414     f->do_oop((oop*)entry->chunk_addr());
1415     entry = entry->parent();
1416   }
1417 
1418   // Due to lightweight locking
1419   lock_stack().oops_do(f);
1420 }
1421 
1422 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1423   if (!has_last_Java_frame()) {
1424     return;
1425   }
1426   // Finish any pending lazy GC activity for the frames
1427   StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1428   // Traverse the execution stack
1429   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1430     fst.current()->oops_do(f, cf, fst.register_map());
1431   }
1432 }
1433 
1434 #ifdef ASSERT
1435 void JavaThread::verify_states_for_handshake() {
1436   // This checks that the thread has a correct frame state during a handshake.
1437   verify_frame_info();
1438 }
1439 #endif
1440 
1441 void JavaThread::nmethods_do(NMethodClosure* cf) {
1442   DEBUG_ONLY(verify_frame_info();)
1443   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1444 
1445   if (has_last_Java_frame()) {
1446     // Traverse the execution stack
1447     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1448       fst.current()->nmethod_do(cf);
1449     }
1450   }
1451 
1452   if (jvmti_thread_state() != nullptr) {
1453     jvmti_thread_state()->nmethods_do(cf);
1454   }
1455 
1456 #if INCLUDE_JVMCI
1457   if (_live_nmethod != nullptr) {
1458     cf->do_nmethod(_live_nmethod);
1459   }
1460 #endif
1461 }
1462 
1463 void JavaThread::metadata_do(MetadataClosure* f) {
1464   if (has_last_Java_frame()) {
1465     // Traverse the execution stack to call f() on the methods in the stack
1466     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1467       fst.current()->metadata_do(f);
1468     }
1469   } else if (is_Compiler_thread()) {
1470     // need to walk ciMetadata in current compile tasks to keep alive.
1471     CompilerThread* ct = (CompilerThread*)this;
1472     if (ct->env() != nullptr) {
1473       ct->env()->metadata_do(f);
1474     }
1475     CompileTask* task = ct->task();
1476     if (task != nullptr) {
1477       task->metadata_do(f);
1478     }
1479   }
1480 }
1481 
1482 // Printing
1483 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1484   switch (_thread_state) {
1485   case _thread_uninitialized:     return "_thread_uninitialized";
1486   case _thread_new:               return "_thread_new";
1487   case _thread_new_trans:         return "_thread_new_trans";
1488   case _thread_in_native:         return "_thread_in_native";
1489   case _thread_in_native_trans:   return "_thread_in_native_trans";
1490   case _thread_in_vm:             return "_thread_in_vm";
1491   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1492   case _thread_in_Java:           return "_thread_in_Java";
1493   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1494   case _thread_blocked:           return "_thread_blocked";
1495   case _thread_blocked_trans:     return "_thread_blocked_trans";
1496   default:                        return "unknown thread state";
1497   }
1498 }
1499 
1500 void JavaThread::print_thread_state_on(outputStream *st) const {
1501   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1502 }
1503 
1504 // Called by Threads::print() for VM_PrintThreads operation
1505 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1506   st->print_raw("\"");
1507   st->print_raw(name());
1508   st->print_raw("\" ");
1509   oop thread_oop = threadObj();
1510   if (thread_oop != nullptr) {
1511     st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1512     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
1513     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1514   }
1515   Thread::print_on(st, print_extended_info);
1516   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1517   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1518   if (thread_oop != nullptr) {
1519     if (is_vthread_mounted()) {
1520       st->print_cr("   Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1521     } else {
1522       st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1523     }
1524   }
1525 #ifndef PRODUCT
1526   _safepoint_state->print_on(st);
1527 #endif // PRODUCT
1528   if (is_Compiler_thread()) {
1529     CompileTask *task = ((CompilerThread*)this)->task();
1530     if (task != nullptr) {
1531       st->print("   Compiling: ");
1532       task->print(st, nullptr, true, false);
1533     } else {
1534       st->print("   No compile task");
1535     }
1536     st->cr();
1537   }
1538 }
1539 
1540 void JavaThread::print() const { print_on(tty); }
1541 
1542 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1543   st->print("%s", get_thread_name_string(buf, buflen));
1544 }
1545 
1546 // Called by fatal error handler. The difference between this and
1547 // JavaThread::print() is that we can't grab lock or allocate memory.
1548 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1549   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1550   Thread* current = Thread::current_or_null_safe();
1551   assert(current != nullptr, "cannot be called by a detached thread");
1552   st->fill_to(60);
1553   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1554     // Only access threadObj() if current thread is not a JavaThread
1555     // or if it is a JavaThread that can safely access oops.
1556     oop thread_obj = threadObj();
1557     if (thread_obj != nullptr) {
1558       st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : "       ");
1559     }
1560   }
1561   st->print(" [");
1562   st->print("%s", _get_thread_state_name(_thread_state));
1563   if (osthread()) {
1564     st->print(", id=%d", osthread()->thread_id());
1565   }
1566   // Use raw field members for stack base/size as this could be
1567   // called before a thread has run enough to initialize them.
1568   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1569             p2i(_stack_base - _stack_size), p2i(_stack_base),
1570             PROPERFMTARGS(_stack_size));
1571   st->print("]");
1572 
1573   ThreadsSMRSupport::print_info_on(this, st);
1574   return;
1575 }
1576 
1577 
1578 // Verification
1579 
1580 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1581   // ignore if there is no stack
1582   if (!has_last_Java_frame()) return;
1583   // traverse the stack frames. Starts from top frame.
1584   for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1585     frame* fr = fst.current();
1586     f(fr, fst.register_map());
1587   }
1588 }
1589 
1590 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1591 
1592 void JavaThread::verify() {
1593   // Verify oops in the thread.
1594   oops_do(&VerifyOopClosure::verify_oop, nullptr);
1595 
1596   // Verify the stack frames.
1597   frames_do(frame_verify);
1598 }
1599 
1600 // CR 6300358 (sub-CR 2137150)
1601 // Most callers of this method assume that it can't return null but a
1602 // thread may not have a name whilst it is in the process of attaching to
1603 // the VM - see CR 6412693, and there are places where a JavaThread can be
1604 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1605 // if vm exit occurs during initialization). These cases can all be accounted
1606 // for such that this method never returns null.
1607 const char* JavaThread::name() const  {
1608   if (Thread::is_JavaThread_protected(/* target */ this)) {
1609     // The target JavaThread is protected so get_thread_name_string() is safe:
1610     return get_thread_name_string();
1611   }
1612 
1613   // The target JavaThread is not protected so we return the default:
1614   return Thread::name();
1615 }
1616 
1617 // Like name() but doesn't include the protection check. This must only be
1618 // called when it is known to be safe, even though the protection check can't tell
1619 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1620 const char* JavaThread::name_raw() const  {
1621   return get_thread_name_string();
1622 }
1623 
1624 // Returns a non-null representation of this thread's name, or a suitable
1625 // descriptive string if there is no set name.
1626 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1627   const char* name_str;
1628 #ifdef ASSERT
1629   Thread* current = Thread::current_or_null_safe();
1630   assert(current != nullptr, "cannot be called by a detached thread");
1631   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1632     // Only access threadObj() if current thread is not a JavaThread
1633     // or if it is a JavaThread that can safely access oops.
1634 #endif
1635     oop thread_obj = threadObj();
1636     if (thread_obj != nullptr) {
1637       oop name = java_lang_Thread::name(thread_obj);
1638       if (name != nullptr) {
1639         if (buf == nullptr) {
1640           name_str = java_lang_String::as_utf8_string(name);
1641         } else {
1642           name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1643         }
1644       } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1645         name_str = "<no-name - thread is attaching>";
1646       } else {
1647         name_str = "<un-named>";
1648       }
1649     } else {
1650       name_str = Thread::name();
1651     }
1652 #ifdef ASSERT
1653   } else {
1654     // Current JavaThread has exited...
1655     if (current == this) {
1656       // ... and is asking about itself:
1657       name_str = "<no-name - current JavaThread has exited>";
1658     } else {
1659       // ... and it can't safely determine this JavaThread's name so
1660       // use the default thread name.
1661       name_str = Thread::name();
1662     }
1663   }
1664 #endif
1665   assert(name_str != nullptr, "unexpected null thread name");
1666   return name_str;
1667 }
1668 
1669 // Helper to extract the name from the thread oop for logging.
1670 const char* JavaThread::name_for(oop thread_obj) {
1671   assert(thread_obj != nullptr, "precondition");
1672   oop name = java_lang_Thread::name(thread_obj);
1673   const char* name_str;
1674   if (name != nullptr) {
1675     name_str = java_lang_String::as_utf8_string(name);
1676   } else {
1677     name_str = "<un-named>";
1678   }
1679   return name_str;
1680 }
1681 
1682 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1683 
1684   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1685   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1686   // Link Java Thread object <-> C++ Thread
1687 
1688   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1689   // and put it into a new Handle.  The Handle "thread_oop" can then
1690   // be used to pass the C++ thread object to other methods.
1691 
1692   // Set the Java level thread object (jthread) field of the
1693   // new thread (a JavaThread *) to C++ thread object using the
1694   // "thread_oop" handle.
1695 
1696   // Set the thread field (a JavaThread *) of the
1697   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1698 
1699   Handle thread_oop(Thread::current(),
1700                     JNIHandles::resolve_non_null(jni_thread));
1701   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1702          "must be initialized");
1703   set_threadOopHandles(thread_oop());
1704   set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1705 
1706   if (prio == NoPriority) {
1707     prio = java_lang_Thread::priority(thread_oop());
1708     assert(prio != NoPriority, "A valid priority should be present");
1709   }
1710 
1711   // Push the Java priority down to the native thread; needs Threads_lock
1712   Thread::set_priority(this, prio);
1713 
1714   // Add the new thread to the Threads list and set it in motion.
1715   // We must have threads lock in order to call Threads::add.
1716   // It is crucial that we do not block before the thread is
1717   // added to the Threads list for if a GC happens, then the java_thread oop
1718   // will not be visited by GC.
1719   Threads::add(this);
1720   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1721   // on a ThreadsList. We don't want to wait for the release when the
1722   // Theads_lock is dropped somewhere in the caller since the JavaThread*
1723   // is already visible to JVM/TI via the ThreadsList.
1724   java_lang_Thread::release_set_thread(thread_oop(), this);
1725 }
1726 
1727 oop JavaThread::current_park_blocker() {
1728   // Support for JSR-166 locks
1729   oop thread_oop = threadObj();
1730   if (thread_oop != nullptr) {
1731     return java_lang_Thread::park_blocker(thread_oop);
1732   }
1733   return nullptr;
1734 }
1735 
1736 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1737 // This is the external format, selecting the platform or vthread
1738 // as applicable, and allowing for a native-only stack.
1739 void JavaThread::print_jni_stack() {
1740   assert(this == JavaThread::current(), "Can't print stack of other threads");
1741   if (!has_last_Java_frame()) {
1742     ResourceMark rm(this);
1743     char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1744     if (buf == nullptr) {
1745       tty->print_cr("Unable to print native stack - out of memory");
1746       return;
1747     }
1748     NativeStackPrinter nsp(this);
1749     address lastpc = nullptr;
1750     nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1751                     true /*print_source_info */, -1 /* max stack */ );
1752   } else {
1753     print_active_stack_on(tty);
1754   }
1755 }
1756 
1757 void JavaThread::print_stack_on(outputStream* st) {
1758   if (!has_last_Java_frame()) return;
1759 
1760   Thread* current_thread = Thread::current();
1761   ResourceMark rm(current_thread);
1762   HandleMark hm(current_thread);
1763 
1764   RegisterMap reg_map(this,
1765                       RegisterMap::UpdateMap::include,
1766                       RegisterMap::ProcessFrames::include,
1767                       RegisterMap::WalkContinuation::skip);
1768   vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
1769   int count = 0;
1770   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1771     if (f->is_java_frame()) {
1772       javaVFrame* jvf = javaVFrame::cast(f);
1773       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1774 
1775       // Print out lock information
1776       if (JavaMonitorsInStackTrace) {
1777         jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1778       }
1779     } else {
1780       // Ignore non-Java frames
1781     }
1782 
1783     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1784     count++;
1785     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1786   }
1787 }
1788 
1789 void JavaThread::print_vthread_stack_on(outputStream* st) {
1790   assert(is_vthread_mounted(), "Caller should have checked this");
1791   assert(has_last_Java_frame(), "must be");
1792 
1793   Thread* current_thread = Thread::current();
1794   ResourceMark rm(current_thread);
1795   HandleMark hm(current_thread);
1796 
1797   RegisterMap reg_map(this,
1798                       RegisterMap::UpdateMap::include,
1799                       RegisterMap::ProcessFrames::include,
1800                       RegisterMap::WalkContinuation::include);
1801   ContinuationEntry* cont_entry = last_continuation();
1802   vframe* start_vf = last_java_vframe(&reg_map);
1803   int count = 0;
1804   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1805     // Watch for end of vthread stack
1806     if (Continuation::is_continuation_enterSpecial(f->fr())) {
1807       assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1808       if (cont_entry->is_virtual_thread()) {
1809         break;
1810       }
1811       cont_entry = cont_entry->parent();
1812     }
1813     if (f->is_java_frame()) {
1814       javaVFrame* jvf = javaVFrame::cast(f);
1815       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1816 
1817       // Print out lock information
1818       if (JavaMonitorsInStackTrace) {
1819         jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1820       }
1821     } else {
1822       // Ignore non-Java frames
1823     }
1824 
1825     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1826     count++;
1827     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1828   }
1829 }
1830 
1831 void JavaThread::print_active_stack_on(outputStream* st) {
1832   if (is_vthread_mounted()) {
1833     print_vthread_stack_on(st);
1834   } else {
1835     print_stack_on(st);
1836   }
1837 }
1838 
1839 #if INCLUDE_JVMTI
1840 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1841 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1842   set_jvmti_vthread(thread_oop);
1843 
1844   // unbind current JvmtiThreadState from JavaThread
1845   JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1846 
1847   // bind new JvmtiThreadState to JavaThread
1848   JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1849 
1850   // enable interp_only_mode for virtual or carrier thread if it has pending bit
1851   JvmtiThreadState::process_pending_interp_only(this);
1852 
1853   return jvmti_thread_state();
1854 }
1855 #endif
1856 
1857 // JVMTI PopFrame support
1858 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1859   assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1860   if (in_bytes(size_in_bytes) != 0) {
1861     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1862     _popframe_preserved_args_size = in_bytes(size_in_bytes);
1863     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1864   }
1865 }
1866 
1867 void* JavaThread::popframe_preserved_args() {
1868   return _popframe_preserved_args;
1869 }
1870 
1871 ByteSize JavaThread::popframe_preserved_args_size() {
1872   return in_ByteSize(_popframe_preserved_args_size);
1873 }
1874 
1875 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1876   int sz = in_bytes(popframe_preserved_args_size());
1877   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1878   return in_WordSize(sz / wordSize);
1879 }
1880 
1881 void JavaThread::popframe_free_preserved_args() {
1882   assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1883   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1884   _popframe_preserved_args = nullptr;
1885   _popframe_preserved_args_size = 0;
1886 }
1887 
1888 #ifndef PRODUCT
1889 
1890 void JavaThread::trace_frames() {
1891   tty->print_cr("[Describe stack]");
1892   int frame_no = 1;
1893   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1894     tty->print("  %d. ", frame_no++);
1895     fst.current()->print_value_on(tty);
1896     tty->cr();
1897   }
1898 }
1899 
1900 class PrintAndVerifyOopClosure: public OopClosure {
1901  protected:
1902   template <class T> inline void do_oop_work(T* p) {
1903     oop obj = RawAccess<>::oop_load(p);
1904     if (obj == nullptr) return;
1905     tty->print(INTPTR_FORMAT ": ", p2i(p));
1906     if (oopDesc::is_oop_or_null(obj)) {
1907       if (obj->is_objArray()) {
1908         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1909       } else {
1910         obj->print();
1911       }
1912     } else {
1913       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1914     }
1915     tty->cr();
1916   }
1917  public:
1918   virtual void do_oop(oop* p) { do_oop_work(p); }
1919   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
1920 };
1921 
1922 #ifdef ASSERT
1923 // Print or validate the layout of stack frames
1924 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1925   ResourceMark rm;
1926   PreserveExceptionMark pm(this);
1927   FrameValues values;
1928   int frame_no = 0;
1929   for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1930     fst.current()->describe(values, ++frame_no, fst.register_map());
1931     if (depth == frame_no) break;
1932   }
1933   Continuation::describe(values);
1934   if (validate_only) {
1935     values.validate();
1936   } else {
1937     tty->print_cr("[Describe stack layout]");
1938     values.print(this);
1939   }
1940 }
1941 #endif
1942 
1943 void JavaThread::trace_stack_from(vframe* start_vf) {
1944   ResourceMark rm;
1945   int vframe_no = 1;
1946   for (vframe* f = start_vf; f; f = f->sender()) {
1947     if (f->is_java_frame()) {
1948       javaVFrame::cast(f)->print_activation(vframe_no++);
1949     } else {
1950       f->print();
1951     }
1952     if (vframe_no > StackPrintLimit) {
1953       tty->print_cr("...<more frames>...");
1954       return;
1955     }
1956   }
1957 }
1958 
1959 
1960 void JavaThread::trace_stack() {
1961   if (!has_last_Java_frame()) return;
1962   Thread* current_thread = Thread::current();
1963   ResourceMark rm(current_thread);
1964   HandleMark hm(current_thread);
1965   RegisterMap reg_map(this,
1966                       RegisterMap::UpdateMap::include,
1967                       RegisterMap::ProcessFrames::include,
1968                       RegisterMap::WalkContinuation::skip);
1969   trace_stack_from(last_java_vframe(&reg_map));
1970 }
1971 
1972 
1973 #endif // PRODUCT
1974 
1975 frame JavaThread::vthread_last_frame() {
1976   assert (is_vthread_mounted(), "Virtual thread not mounted");
1977   return last_frame();
1978 }
1979 
1980 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1981   const ContinuationEntry* entry = vthread_continuation();
1982   guarantee (entry != nullptr, "Not a carrier thread");
1983   frame f = entry->to_frame();
1984   if (reg_map->process_frames()) {
1985     entry->flush_stack_processing(this);
1986   }
1987   entry->update_register_map(reg_map);
1988   return f.sender(reg_map);
1989 }
1990 
1991 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1992   return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1993 }
1994 
1995 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
1996   assert(reg_map != nullptr, "a map must be given");
1997   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
1998     if (vf->is_java_frame()) return javaVFrame::cast(vf);
1999   }
2000   return nullptr;
2001 }
2002 
2003 Klass* JavaThread::security_get_caller_class(int depth) {
2004   ResetNoHandleMark rnhm;
2005   HandleMark hm(Thread::current());
2006 
2007   vframeStream vfst(this);
2008   vfst.security_get_caller_frame(depth);
2009   if (!vfst.at_end()) {
2010     return vfst.method()->method_holder();
2011   }
2012   return nullptr;
2013 }
2014 
2015 // Internal convenience function for millisecond resolution sleeps.
2016 bool JavaThread::sleep(jlong millis) {
2017   jlong nanos;
2018   if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2019     // Conversion to nanos would overflow, saturate at max
2020     nanos = max_jlong;
2021   } else {
2022     nanos = millis * NANOUNITS_PER_MILLIUNIT;
2023   }
2024   return sleep_nanos(nanos);
2025 }
2026 
2027 // java.lang.Thread.sleep support
2028 // Returns true if sleep time elapsed as expected, and false
2029 // if the thread was interrupted or async exception was installed.
2030 bool JavaThread::sleep_nanos(jlong nanos) {
2031   assert(this == Thread::current(),  "thread consistency check");
2032   assert(nanos >= 0, "nanos are in range");
2033 
2034   ParkEvent * const slp = this->_SleepEvent;
2035   // Because there can be races with thread interruption sending an unpark()
2036   // to the event, we explicitly reset it here to avoid an immediate return.
2037   // The actual interrupt state will be checked before we park().
2038   slp->reset();
2039   // Thread interruption establishes a happens-before ordering in the
2040   // Java Memory Model, so we need to ensure we synchronize with the
2041   // interrupt state.
2042   OrderAccess::fence();
2043 
2044   jlong prevtime = os::javaTimeNanos();
2045 
2046   jlong nanos_remaining = nanos;
2047 
2048   for (;;) {
2049     if (has_async_exception_condition()) {
2050       return false;
2051     }
2052     // interruption has precedence over timing out
2053     if (this->is_interrupted(true)) {
2054       return false;
2055     }
2056 
2057     if (nanos_remaining <= 0) {
2058       return true;
2059     }
2060 
2061     {
2062       ThreadBlockInVM tbivm(this);
2063       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2064       slp->park_nanos(nanos_remaining);
2065     }
2066 
2067     // Update elapsed time tracking
2068     jlong newtime = os::javaTimeNanos();
2069     if (newtime - prevtime < 0) {
2070       // time moving backwards, should only happen if no monotonic clock
2071       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2072       assert(false,
2073              "unexpected time moving backwards detected in JavaThread::sleep()");
2074     } else {
2075       nanos_remaining -= (newtime - prevtime);
2076     }
2077     prevtime = newtime;
2078   }
2079 }
2080 
2081 // Last thread running calls java.lang.Shutdown.shutdown()
2082 void JavaThread::invoke_shutdown_hooks() {
2083   HandleMark hm(this);
2084 
2085   // We could get here with a pending exception, if so clear it now.
2086   if (this->has_pending_exception()) {
2087     this->clear_pending_exception();
2088   }
2089 
2090   EXCEPTION_MARK;
2091   Klass* shutdown_klass =
2092     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2093                                       THREAD);
2094   if (shutdown_klass != nullptr) {
2095     // SystemDictionary::resolve_or_null will return null if there was
2096     // an exception.  If we cannot load the Shutdown class, just don't
2097     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
2098     // won't be run.  Note that if a shutdown hook was registered,
2099     // the Shutdown class would have already been loaded
2100     // (Runtime.addShutdownHook will load it).
2101     JavaValue result(T_VOID);
2102     JavaCalls::call_static(&result,
2103                            shutdown_klass,
2104                            vmSymbols::shutdown_name(),
2105                            vmSymbols::void_method_signature(),
2106                            THREAD);
2107   }
2108   CLEAR_PENDING_EXCEPTION;
2109 }
2110 
2111 #ifndef PRODUCT
2112 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2113    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2114 }
2115 #endif
2116 
2117 // Helper function to create the java.lang.Thread object for a
2118 // VM-internal thread. The thread will have the given name, and be
2119 // a member of the "system" ThreadGroup.
2120 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2121   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2122 
2123   // Initialize thread_oop to put it into the system threadGroup.
2124   // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2125   Handle thread_group(THREAD, Universe::system_thread_group());
2126   Handle thread_oop =
2127     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2128                                       vmSymbols::threadgroup_string_void_signature(),
2129                                       thread_group,
2130                                       string,
2131                                       CHECK_NH);
2132 
2133   return thread_oop;
2134 }
2135 
2136 // Starts the target JavaThread as a daemon of the given priority, and
2137 // bound to the given java.lang.Thread instance.
2138 // The Threads_lock is held for the duration.
2139 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2140                                        Handle thread_oop, ThreadPriority prio) {
2141 
2142   assert(target->osthread() != nullptr, "target thread is not properly initialized");
2143 
2144   MutexLocker mu(current, Threads_lock);
2145 
2146   // Initialize the fields of the thread_oop first.
2147   if (prio != NoPriority) {
2148     java_lang_Thread::set_priority(thread_oop(), prio);
2149     // Note: we don't call os::set_priority here. Possibly we should,
2150     // else all threads should call it themselves when they first run.
2151   }
2152 
2153   java_lang_Thread::set_daemon(thread_oop());
2154 
2155   // Now bind the thread_oop to the target JavaThread.
2156   target->set_threadOopHandles(thread_oop());
2157   target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2158 
2159   Threads::add(target); // target is now visible for safepoint/handshake
2160   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2161   // on a ThreadsList. We don't want to wait for the release when the
2162   // Theads_lock is dropped when the 'mu' destructor is run since the
2163   // JavaThread* is already visible to JVM/TI via the ThreadsList.
2164 
2165   assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2166   java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2167   Thread::start(target);
2168 }
2169 
2170 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2171   // At this point it may be possible that no osthread was created for the
2172   // JavaThread due to lack of resources. However, since this must work
2173   // for critical system threads just check and abort if this fails.
2174   if (thread->osthread() == nullptr) {
2175     // This isn't really an OOM condition, but historically this is what
2176     // we report.
2177     vm_exit_during_initialization("java.lang.OutOfMemoryError",
2178                                   os::native_thread_creation_failed_msg());
2179   }
2180 }
2181 
2182 void JavaThread::pretouch_stack() {
2183   // Given an established java thread stack with usable area followed by
2184   // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2185   // from the current frame down to the start of the shadow zone.
2186   const address end = _stack_overflow_state.shadow_zone_safe_limit();
2187   if (is_in_full_stack(end)) {
2188     char* p1 = (char*) alloca(1);
2189     address here = (address) &p1;
2190     if (is_in_full_stack(here) && here > end) {
2191       size_t to_alloc = here - end;
2192       char* p2 = (char*) alloca(to_alloc);
2193       log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2194                             (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2195       os::pretouch_memory(p2, p2 + to_alloc,
2196                           NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2197     }
2198   }
2199 }
2200 
2201 // Deferred OopHandle release support.
2202 
2203 class OopHandleList : public CHeapObj<mtInternal> {
2204   static const int _count = 4;
2205   OopHandle _handles[_count];
2206   OopHandleList* _next;
2207   int _index;
2208  public:
2209   OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2210   void add(OopHandle h) {
2211     assert(_index < _count, "too many additions");
2212     _handles[_index++] = h;
2213   }
2214   ~OopHandleList() {
2215     assert(_index == _count, "usage error");
2216     for (int i = 0; i < _index; i++) {
2217       _handles[i].release(JavaThread::thread_oop_storage());
2218     }
2219   }
2220   OopHandleList* next() const { return _next; }
2221 };
2222 
2223 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2224 
2225 // Called by the ServiceThread to do the work of releasing
2226 // the OopHandles.
2227 void JavaThread::release_oop_handles() {
2228   OopHandleList* list;
2229   {
2230     MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2231     list = _oop_handle_list;
2232     _oop_handle_list = nullptr;
2233   }
2234   assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2235 
2236   while (list != nullptr) {
2237     OopHandleList* l = list;
2238     list = l->next();
2239     delete l;
2240   }
2241 }
2242 
2243 // Add our OopHandles for later release.
2244 void JavaThread::add_oop_handles_for_release() {
2245   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2246   OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2247   new_head->add(_threadObj);
2248   new_head->add(_vthread);
2249   new_head->add(_jvmti_vthread);
2250   new_head->add(_scopedValueCache);
2251   _oop_handle_list = new_head;
2252   Service_lock->notify_all();
2253 }
2254 
2255 #if INCLUDE_JFR
2256 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2257   assert(result != freeze_ok, "sanity check");
2258   _last_freeze_fail_result = result;
2259   _last_freeze_fail_time = Ticks::now();
2260 }
2261 
2262 // Post jdk.VirtualThreadPinned event
2263 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2264   assert(result != freeze_ok, "sanity check");
2265   if (event->should_commit()) {
2266     char reason[256];
2267     if (class_to_be_initialized() != nullptr) {
2268       ResourceMark rm(this);
2269       jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2270                    class_to_be_initialized()->external_name());
2271       event->set_pinnedReason(reason);
2272     } else if (class_being_initialized() != nullptr) {
2273       ResourceMark rm(this);
2274       jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2275                    class_being_initialized()->external_name());
2276       event->set_pinnedReason(reason);
2277     } else if (result == freeze_pinned_native) {
2278       event->set_pinnedReason("Native or VM frame on stack");
2279     } else {
2280       jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2281       event->set_pinnedReason(reason);
2282     }
2283     event->set_blockingOperation(op);
2284     event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2285     event->commit();
2286   }
2287 }
2288 #endif