1 /*
   2  * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "cds/dynamicArchive.hpp"
  28 #include "ci/ciEnv.hpp"
  29 #include "classfile/javaClasses.inline.hpp"
  30 #include "classfile/javaThreadStatus.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "classfile/vmClasses.hpp"
  33 #include "classfile/vmSymbols.hpp"
  34 #include "code/codeCache.hpp"
  35 #include "code/scopeDesc.hpp"
  36 #include "compiler/compileTask.hpp"
  37 #include "compiler/compilerThread.hpp"
  38 #include "gc/shared/oopStorage.hpp"
  39 #include "gc/shared/oopStorageSet.hpp"
  40 #include "gc/shared/tlab_globals.hpp"
  41 #include "jfr/jfrEvents.hpp"
  42 #include "jvm.h"
  43 #include "jvmtifiles/jvmtiEnv.hpp"
  44 #include "logging/log.hpp"
  45 #include "logging/logAsyncWriter.hpp"
  46 #include "logging/logStream.hpp"
  47 #include "memory/allocation.inline.hpp"
  48 #include "memory/iterator.hpp"
  49 #include "memory/universe.hpp"
  50 #include "oops/access.inline.hpp"
  51 #include "oops/instanceKlass.hpp"
  52 #include "oops/klass.inline.hpp"
  53 #include "oops/oop.inline.hpp"
  54 #include "oops/oopHandle.inline.hpp"
  55 #include "oops/verifyOopClosure.hpp"
  56 #include "prims/jvm_misc.hpp"
  57 #include "prims/jvmtiDeferredUpdates.hpp"
  58 #include "prims/jvmtiExport.hpp"
  59 #include "prims/jvmtiThreadState.inline.hpp"
  60 #include "runtime/atomic.hpp"
  61 #include "runtime/continuation.hpp"
  62 #include "runtime/continuationEntry.inline.hpp"
  63 #include "runtime/continuationHelper.inline.hpp"
  64 #include "runtime/deoptimization.hpp"
  65 #include "runtime/frame.inline.hpp"
  66 #include "runtime/handles.inline.hpp"
  67 #include "runtime/handshake.hpp"
  68 #include "runtime/interfaceSupport.inline.hpp"
  69 #include "runtime/java.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/javaThread.inline.hpp"
  72 #include "runtime/jniHandles.inline.hpp"
  73 #include "runtime/lockStack.inline.hpp"
  74 #include "runtime/mutexLocker.hpp"
  75 #include "runtime/orderAccess.hpp"
  76 #include "runtime/os.inline.hpp"
  77 #include "runtime/osThread.hpp"
  78 #include "runtime/safepoint.hpp"
  79 #include "runtime/safepointMechanism.inline.hpp"
  80 #include "runtime/safepointVerifiers.hpp"
  81 #include "runtime/serviceThread.hpp"
  82 #include "runtime/stackFrameStream.inline.hpp"
  83 #include "runtime/stackWatermarkSet.hpp"
  84 #include "runtime/synchronizer.hpp"
  85 #include "runtime/threadCritical.hpp"

  86 #include "runtime/threadSMR.inline.hpp"
  87 #include "runtime/threadStatisticalInfo.hpp"
  88 #include "runtime/threadWXSetters.inline.hpp"
  89 #include "runtime/timer.hpp"
  90 #include "runtime/timerTrace.hpp"
  91 #include "runtime/vframe.inline.hpp"
  92 #include "runtime/vframeArray.hpp"
  93 #include "runtime/vframe_hp.hpp"
  94 #include "runtime/vmThread.hpp"
  95 #include "runtime/vmOperations.hpp"
  96 #include "services/threadService.hpp"
  97 #include "utilities/copy.hpp"
  98 #include "utilities/defaultStream.hpp"
  99 #include "utilities/dtrace.hpp"
 100 #include "utilities/events.hpp"
 101 #include "utilities/macros.hpp"
 102 #include "utilities/preserveException.hpp"
 103 #include "utilities/spinYield.hpp"
 104 #include "utilities/vmError.hpp"
 105 #if INCLUDE_JVMCI
 106 #include "jvmci/jvmci.hpp"
 107 #include "jvmci/jvmciEnv.hpp"
 108 #endif
 109 #if INCLUDE_JFR
 110 #include "jfr/jfr.hpp"
 111 #endif
 112 
 113 // Set by os layer.
 114 size_t      JavaThread::_stack_size_at_create = 0;
 115 
 116 #ifdef DTRACE_ENABLED
 117 
 118 // Only bother with this argument setup if dtrace is available
 119 
 120   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 121   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 122 
 123   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 124     {                                                                      \
 125       ResourceMark rm(this);                                               \
 126       int len = 0;                                                         \
 127       const char* name = (javathread)->name();                             \
 128       len = strlen(name);                                                  \
 129       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 130         (char *) name, len,                                                \
 131         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 132         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 133         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 134     }
 135 
 136 #else //  ndef DTRACE_ENABLED
 137 
 138   #define DTRACE_THREAD_PROBE(probe, javathread)
 139 
 140 #endif // ndef DTRACE_ENABLED
 141 
 142 void JavaThread::smr_delete() {
 143   if (_on_thread_list) {
 144     ThreadsSMRSupport::smr_delete(this);
 145   } else {
 146     delete this;
 147   }
 148 }
 149 
 150 // Initialized by VMThread at vm_global_init
 151 OopStorage* JavaThread::_thread_oop_storage = nullptr;
 152 
 153 OopStorage* JavaThread::thread_oop_storage() {
 154   assert(_thread_oop_storage != nullptr, "not yet initialized");
 155   return _thread_oop_storage;
 156 }
 157 
 158 void JavaThread::set_threadOopHandles(oop p) {
 159   assert(_thread_oop_storage != nullptr, "not yet initialized");
 160   _threadObj   = OopHandle(_thread_oop_storage, p);
 161   _vthread     = OopHandle(_thread_oop_storage, p);
 162   _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
 163   _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
 164 }
 165 
 166 oop JavaThread::threadObj() const {
 167   // Ideally we would verify the current thread is oop_safe when this is called, but as we can
 168   // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
 169   // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
 170   // Instead callers must verify oop safe access.
 171   return _threadObj.resolve();
 172 }
 173 
 174 oop JavaThread::vthread() const {
 175   return _vthread.resolve();
 176 }
 177 
 178 void JavaThread::set_vthread(oop p) {
 179   assert(_thread_oop_storage != nullptr, "not yet initialized");
 180   _vthread.replace(p);
 181 }
 182 
 183 oop JavaThread::jvmti_vthread() const {
 184   return _jvmti_vthread.resolve();
 185 }
 186 
 187 void JavaThread::set_jvmti_vthread(oop p) {
 188   assert(_thread_oop_storage != nullptr, "not yet initialized");
 189   _jvmti_vthread.replace(p);
 190 }
 191 
 192 // If there is a virtual thread mounted then return vthread() oop.
 193 // Otherwise, return threadObj().
 194 oop JavaThread::vthread_or_thread() const {
 195   oop result = vthread();
 196   if (result == nullptr) {
 197     result = threadObj();
 198   }
 199   return result;
 200 }
 201 
 202 oop JavaThread::scopedValueCache() const {
 203   return _scopedValueCache.resolve();
 204 }
 205 
 206 void JavaThread::set_scopedValueCache(oop p) {
 207   if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
 208     _scopedValueCache.replace(p);
 209   } else {
 210     assert(p == nullptr, "not yet initialized");
 211   }
 212 }
 213 
 214 void JavaThread::clear_scopedValueBindings() {
 215   set_scopedValueCache(nullptr);
 216   oop vthread_oop = vthread();
 217   // vthread may be null here if we get a VM error during startup,
 218   // before the java.lang.Thread instance has been created.
 219   if (vthread_oop != nullptr) {
 220     java_lang_Thread::clear_scopedValueBindings(vthread_oop);
 221   }
 222 }
 223 
 224 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 225                                     bool daemon, TRAPS) {
 226   assert(thread_group.not_null(), "thread group should be specified");
 227   assert(threadObj() == nullptr, "should only create Java thread object once");
 228 
 229   InstanceKlass* ik = vmClasses::Thread_klass();
 230   assert(ik->is_initialized(), "must be");
 231   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 232 
 233   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 234   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 235   // constructor calls Thread.current(), which must be set here.
 236   java_lang_Thread::set_thread(thread_oop(), this);
 237   set_threadOopHandles(thread_oop());


 238 
 239   JavaValue result(T_VOID);
 240   if (thread_name != nullptr) {
 241     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 242     // Thread gets assigned specified name and null target
 243     JavaCalls::call_special(&result,
 244                             thread_oop,
 245                             ik,
 246                             vmSymbols::object_initializer_name(),
 247                             vmSymbols::threadgroup_string_void_signature(),
 248                             thread_group,
 249                             name,
 250                             CHECK);
 251   } else {
 252     // Thread gets assigned name "Thread-nnn" and null target
 253     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 254     JavaCalls::call_special(&result,
 255                             thread_oop,
 256                             ik,
 257                             vmSymbols::object_initializer_name(),
 258                             vmSymbols::threadgroup_runnable_void_signature(),
 259                             thread_group,
 260                             Handle(),
 261                             CHECK);
 262   }



 263   os::set_priority(this, NormPriority);
 264 
 265   if (daemon) {
 266     java_lang_Thread::set_daemon(thread_oop());
 267   }
 268 }
 269 
 270 // ======= JavaThread ========
 271 
 272 #if INCLUDE_JVMCI
 273 
 274 jlong* JavaThread::_jvmci_old_thread_counters;
 275 
 276 static bool jvmci_counters_include(JavaThread* thread) {
 277   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 278 }
 279 
 280 void JavaThread::collect_counters(jlong* array, int length) {
 281   assert(length == JVMCICounterSize, "wrong value");
 282   for (int i = 0; i < length; i++) {
 283     array[i] = _jvmci_old_thread_counters[i];
 284   }
 285   for (JavaThread* tp : ThreadsListHandle()) {
 286     if (jvmci_counters_include(tp)) {
 287       for (int i = 0; i < length; i++) {
 288         array[i] += tp->_jvmci_counters[i];
 289       }
 290     }
 291   }
 292 }
 293 
 294 // Attempt to enlarge the array for per thread counters.
 295 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 296   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 297   if (new_counters == nullptr) {
 298     return nullptr;
 299   }
 300   if (old_counters == nullptr) {
 301     old_counters = new_counters;
 302     memset(old_counters, 0, sizeof(jlong) * new_size);
 303   } else {
 304     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 305       new_counters[i] = old_counters[i];
 306     }
 307     if (new_size > current_size) {
 308       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 309     }
 310     FREE_C_HEAP_ARRAY(jlong, old_counters);
 311   }
 312   return new_counters;
 313 }
 314 
 315 // Attempt to enlarge the array for per thread counters.
 316 bool JavaThread::resize_counters(int current_size, int new_size) {
 317   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 318   if (new_counters == nullptr) {
 319     return false;
 320   } else {
 321     _jvmci_counters = new_counters;
 322     return true;
 323   }
 324 }
 325 
 326 class VM_JVMCIResizeCounters : public VM_Operation {
 327  private:
 328   int _new_size;
 329   bool _failed;
 330 
 331  public:
 332   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 333   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 334   bool allow_nested_vm_operations() const        { return true; }
 335   void doit() {
 336     // Resize the old thread counters array
 337     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 338     if (new_counters == nullptr) {
 339       _failed = true;
 340       return;
 341     } else {
 342       JavaThread::_jvmci_old_thread_counters = new_counters;
 343     }
 344 
 345     // Now resize each threads array
 346     for (JavaThread* tp : ThreadsListHandle()) {
 347       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 348         _failed = true;
 349         break;
 350       }
 351     }
 352     if (!_failed) {
 353       JVMCICounterSize = _new_size;
 354     }
 355   }
 356 
 357   bool failed() { return _failed; }
 358 };
 359 
 360 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 361   VM_JVMCIResizeCounters op(new_size);
 362   VMThread::execute(&op);
 363   return !op.failed();
 364 }
 365 
 366 #endif // INCLUDE_JVMCI
 367 
 368 #ifdef ASSERT
 369 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 370 void JavaThread::check_possible_safepoint() {
 371   if (_no_safepoint_count > 0) {
 372     print_owned_locks();
 373     assert(false, "Possible safepoint reached by thread that does not allow it");
 374   }
 375 #ifdef CHECK_UNHANDLED_OOPS
 376   // Clear unhandled oops in JavaThreads so we get a crash right away.
 377   clear_unhandled_oops();
 378 #endif // CHECK_UNHANDLED_OOPS
 379 
 380   // Macos/aarch64 should be in the right state for safepoint (e.g.
 381   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 382   // happens in practice, making such issues hard to find and reproduce.
 383 #if defined(__APPLE__) && defined(AARCH64)
 384   if (AssertWXAtThreadSync) {
 385     assert_wx_state(WXWrite);
 386   }
 387 #endif
 388 }
 389 
 390 void JavaThread::check_for_valid_safepoint_state() {
 391   // Don't complain if running a debugging command.
 392   if (DebuggingContext::is_enabled()) return;
 393 
 394   // Check NoSafepointVerifier, which is implied by locks taken that can be
 395   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 396   // are held.
 397   check_possible_safepoint();
 398 
 399   if (thread_state() != _thread_in_vm) {
 400     fatal("LEAF method calling lock?");
 401   }
 402 
 403   if (GCALotAtAllSafepoints) {
 404     // We could enter a safepoint here and thus have a gc
 405     InterfaceSupport::check_gc_alot();
 406   }
 407 }
 408 #endif // ASSERT
 409 
 410 // A JavaThread is a normal Java thread
 411 
 412 JavaThread::JavaThread() :
 413   // Initialize fields
 414 
 415   _on_thread_list(false),
 416   DEBUG_ONLY(_java_call_counter(0) COMMA)
 417   _entry_point(nullptr),
 418   _deopt_mark(nullptr),
 419   _deopt_nmethod(nullptr),
 420   _vframe_array_head(nullptr),
 421   _vframe_array_last(nullptr),
 422   _jvmti_deferred_updates(nullptr),
 423   _callee_target(nullptr),
 424   _vm_result(nullptr),
 425   _vm_result_2(nullptr),
 426 
 427   _current_pending_monitor(nullptr),
 428   _current_pending_monitor_is_from_java(true),
 429   _current_waiting_monitor(nullptr),
 430   _active_handles(nullptr),
 431   _free_handle_block(nullptr),


 432 
 433   _monitor_chunks(nullptr),
 434 
 435   _suspend_flags(0),
 436 
 437   _thread_state(_thread_new),
 438   _saved_exception_pc(nullptr),
 439 #ifdef ASSERT
 440   _no_safepoint_count(0),
 441   _visited_for_critical_count(false),
 442 #endif
 443 
 444   _terminated(_not_terminated),
 445   _in_deopt_handler(0),
 446   _doing_unsafe_access(false),
 447   _do_not_unlock_if_synchronized(false),
 448 #if INCLUDE_JVMTI
 449   _carrier_thread_suspended(false),
 450   _is_in_VTMS_transition(false),
 451   _is_in_tmp_VTMS_transition(false),
 452   _is_disable_suspend(false),
 453 #ifdef ASSERT
 454   _is_VTMS_transition_disabler(false),
 455 #endif
 456 #endif
 457   _jni_attach_state(_not_attaching_via_jni),
 458 #if INCLUDE_JVMCI
 459   _pending_deoptimization(-1),
 460   _pending_monitorenter(false),
 461   _pending_transfer_to_interpreter(false),
 462   _in_retryable_allocation(false),
 463   _pending_failed_speculation(0),
 464   _jvmci{nullptr},
 465   _libjvmci_runtime(nullptr),
 466   _jvmci_counters(nullptr),
 467   _jvmci_reserved0(0),
 468   _jvmci_reserved1(0),
 469   _jvmci_reserved_oop0(nullptr),
 470 #endif // INCLUDE_JVMCI
 471 
 472   _exception_oop(oop()),
 473   _exception_pc(0),
 474   _exception_handler_pc(0),
 475   _is_method_handle_return(0),
 476 
 477   _jni_active_critical(0),
 478   _pending_jni_exception_check_fn(nullptr),
 479   _depth_first_number(0),
 480 
 481   // JVMTI PopFrame support
 482   _popframe_condition(popframe_inactive),
 483   _frames_to_pop_failed_realloc(0),
 484 
 485   _cont_entry(nullptr),
 486   _cont_fastpath(0),
 487   _cont_fastpath_thread_state(1),
 488   _held_monitor_count(0),
 489   _jni_monitor_count(0),




 490 
 491   _handshake(this),
 492 
 493   _popframe_preserved_args(nullptr),
 494   _popframe_preserved_args_size(0),
 495 
 496   _jvmti_thread_state(nullptr),
 497   _interp_only_mode(0),
 498   _should_post_on_exceptions_flag(JNI_FALSE),
 499   _thread_stat(new ThreadStatistics()),
 500 
 501   _parker(),
 502 
 503   _class_to_be_initialized(nullptr),
 504 
 505   _SleepEvent(ParkEvent::Allocate(this)),
 506 
 507   _lock_stack(this) {
 508   set_jni_functions(jni_functions());
 509 
 510 #if INCLUDE_JVMCI
 511   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
 512   if (JVMCICounterSize > 0) {
 513     resize_counters(0, (int) JVMCICounterSize);
 514   }
 515 #endif // INCLUDE_JVMCI
 516 
 517   // Setup safepoint state info for this thread
 518   ThreadSafepointState::create(this);
 519 
 520   SafepointMechanism::initialize_header(this);
 521 
 522   set_requires_cross_modify_fence(false);
 523 
 524   pd_initialize();
 525   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
 526 }
 527 
 528 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
 529   if (is_attaching_via_jni) {
 530     _jni_attach_state = _attaching_via_jni;
 531   }
 532 }
 533 
 534 
 535 // interrupt support
 536 
 537 void JavaThread::interrupt() {
 538   // All callers should have 'this' thread protected by a
 539   // ThreadsListHandle so that it cannot terminate and deallocate
 540   // itself.
 541   debug_only(check_for_dangling_thread_pointer(this);)
 542 
 543   // For Windows _interrupt_event
 544   WINDOWS_ONLY(osthread()->set_interrupted(true);)
 545 
 546   // For Thread.sleep
 547   _SleepEvent->unpark();
 548 
 549   // For JSR166 LockSupport.park
 550   parker()->unpark();
 551 
 552   // For ObjectMonitor and JvmtiRawMonitor
 553   _ParkEvent->unpark();
 554 }
 555 
 556 bool JavaThread::is_interrupted(bool clear_interrupted) {
 557   debug_only(check_for_dangling_thread_pointer(this);)
 558 
 559   if (_threadObj.peek() == nullptr) {
 560     // If there is no j.l.Thread then it is impossible to have
 561     // been interrupted. We can find null during VM initialization
 562     // or when a JNI thread is still in the process of attaching.
 563     // In such cases this must be the current thread.
 564     assert(this == Thread::current(), "invariant");
 565     return false;
 566   }
 567 
 568   bool interrupted = java_lang_Thread::interrupted(threadObj());
 569 
 570   // NOTE that since there is no "lock" around the interrupt and
 571   // is_interrupted operations, there is the possibility that the
 572   // interrupted flag will be "false" but that the
 573   // low-level events will be in the signaled state. This is
 574   // intentional. The effect of this is that Object.wait() and
 575   // LockSupport.park() will appear to have a spurious wakeup, which
 576   // is allowed and not harmful, and the possibility is so rare that
 577   // it is not worth the added complexity to add yet another lock.
 578   // For the sleep event an explicit reset is performed on entry
 579   // to JavaThread::sleep, so there is no early return. It has also been
 580   // recommended not to put the interrupted flag into the "event"
 581   // structure because it hides the issue.
 582   // Also, because there is no lock, we must only clear the interrupt
 583   // state if we are going to report that we were interrupted; otherwise
 584   // an interrupt that happens just after we read the field would be lost.
 585   if (interrupted && clear_interrupted) {
 586     assert(this == Thread::current(), "only the current thread can clear");
 587     java_lang_Thread::set_interrupted(threadObj(), false);
 588     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 589   }
 590   return interrupted;
 591 }
 592 
 593 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
 594 // the Java code in Object::wait which are not present in RawMonitorWait.
 595 bool JavaThread::get_and_clear_interrupted() {
 596   if (!is_interrupted(false)) {
 597     return false;
 598   }
 599   oop thread_oop = vthread_or_thread();
 600   bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
 601 
 602   if (!is_virtual) {
 603     return is_interrupted(true);
 604   }
 605   // Virtual thread: clear interrupt status for both virtual and
 606   // carrier threads under the interruptLock protection.
 607   JavaThread* current = JavaThread::current();
 608   HandleMark hm(current);
 609   Handle thread_h(current, thread_oop);
 610   ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
 611 
 612   // re-check the interrupt status under the interruptLock protection
 613   bool interrupted = java_lang_Thread::interrupted(thread_h());
 614 
 615   if (interrupted) {
 616     assert(this == Thread::current(), "only the current thread can clear");
 617     java_lang_Thread::set_interrupted(thread_h(), false);  // clear for virtual
 618     java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
 619     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 620   }
 621   return interrupted;
 622 }
 623 
 624 void JavaThread::block_if_vm_exited() {
 625   if (_terminated == _vm_exited) {
 626     // _vm_exited is set at safepoint, and Threads_lock is never released
 627     // so we will block here forever.
 628     // Here we can be doing a jump from a safe state to an unsafe state without
 629     // proper transition, but it happens after the final safepoint has begun so
 630     // this jump won't cause any safepoint problems.
 631     set_thread_state(_thread_in_vm);
 632     Threads_lock->lock();
 633     ShouldNotReachHere();
 634   }
 635 }
 636 
 637 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
 638   _jni_attach_state = _not_attaching_via_jni;
 639   set_entry_point(entry_point);
 640   // Create the native thread itself.
 641   // %note runtime_23
 642   os::ThreadType thr_type = os::java_thread;
 643   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
 644                                                             os::java_thread;
 645   os::create_thread(this, thr_type, stack_sz);
 646   // The _osthread may be null here because we ran out of memory (too many threads active).
 647   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
 648   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
 649   // the exception consists of creating the exception object & initializing it, initialization
 650   // will leave the VM via a JavaCall and then all locks must be unlocked).
 651   //
 652   // The thread is still suspended when we reach here. Thread must be explicit started
 653   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
 654   // by calling Threads:add. The reason why this is not done here, is because the thread
 655   // object must be fully initialized (take a look at JVM_Start)
 656 }
 657 
 658 JavaThread::~JavaThread() {
 659 
 660   // Enqueue OopHandles for release by the service thread.
 661   add_oop_handles_for_release();
 662 
 663   // Return the sleep event to the free list
 664   ParkEvent::Release(_SleepEvent);
 665   _SleepEvent = nullptr;
 666 
 667   // Free any remaining  previous UnrollBlock
 668   vframeArray* old_array = vframe_array_last();
 669 
 670   if (old_array != nullptr) {
 671     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
 672     old_array->set_unroll_block(nullptr);
 673     delete old_info;
 674     delete old_array;
 675   }
 676 
 677   JvmtiDeferredUpdates* updates = deferred_updates();
 678   if (updates != nullptr) {
 679     // This can only happen if thread is destroyed before deoptimization occurs.
 680     assert(updates->count() > 0, "Updates holder not deleted");
 681     // free deferred updates.
 682     delete updates;
 683     set_deferred_updates(nullptr);
 684   }
 685 
 686   // All Java related clean up happens in exit
 687   ThreadSafepointState::destroy(this);
 688   if (_thread_stat != nullptr) delete _thread_stat;
 689 
 690 #if INCLUDE_JVMCI
 691   if (JVMCICounterSize > 0) {
 692     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
 693   }
 694 #endif // INCLUDE_JVMCI
 695 }
 696 
 697 
 698 // First JavaThread specific code executed by a new Java thread.
 699 void JavaThread::pre_run() {
 700   // empty - see comments in run()
 701 }
 702 
 703 // The main routine called by a new Java thread. This isn't overridden
 704 // by subclasses, instead different subclasses define a different "entry_point"
 705 // which defines the actual logic for that kind of thread.
 706 void JavaThread::run() {
 707   // initialize thread-local alloc buffer related fields
 708   initialize_tlab();
 709 
 710   _stack_overflow_state.create_stack_guard_pages();
 711 
 712   cache_global_variables();
 713 
 714   // Thread is now sufficiently initialized to be handled by the safepoint code as being
 715   // in the VM. Change thread state from _thread_new to _thread_in_vm
 716   assert(this->thread_state() == _thread_new, "wrong thread state");
 717   set_thread_state(_thread_in_vm);
 718 
 719   // Before a thread is on the threads list it is always safe, so after leaving the
 720   // _thread_new we should emit a instruction barrier. The distance to modified code
 721   // from here is probably far enough, but this is consistent and safe.
 722   OrderAccess::cross_modify_fence();
 723 
 724   assert(JavaThread::current() == this, "sanity check");
 725   assert(!Thread::current()->owns_locks(), "sanity check");
 726 
 727   DTRACE_THREAD_PROBE(start, this);
 728 
 729   // This operation might block. We call that after all safepoint checks for a new thread has
 730   // been completed.
 731   set_active_handles(JNIHandleBlock::allocate_block());
 732 
 733   if (JvmtiExport::should_post_thread_life()) {
 734     JvmtiExport::post_thread_start(this);
 735 
 736   }
 737 
 738   if (AlwaysPreTouchStacks) {
 739     pretouch_stack();
 740   }
 741 
 742   // We call another function to do the rest so we are sure that the stack addresses used
 743   // from there will be lower than the stack base just computed.
 744   thread_main_inner();
 745 }
 746 
 747 void JavaThread::thread_main_inner() {
 748   assert(JavaThread::current() == this, "sanity check");
 749   assert(_threadObj.peek() != nullptr, "just checking");
 750 
 751   // Execute thread entry point unless this thread has a pending exception.
 752   // Note: Due to JVMTI StopThread we can have pending exceptions already!
 753   if (!this->has_pending_exception()) {
 754     {
 755       ResourceMark rm(this);
 756       this->set_native_thread_name(this->name());
 757     }
 758     HandleMark hm(this);
 759     this->entry_point()(this, this);
 760   }
 761 
 762   DTRACE_THREAD_PROBE(stop, this);
 763 
 764   // Cleanup is handled in post_run()
 765 }
 766 
 767 // Shared teardown for all JavaThreads
 768 void JavaThread::post_run() {
 769   this->exit(false);
 770   this->unregister_thread_stack_with_NMT();
 771   // Defer deletion to here to ensure 'this' is still referenceable in call_run
 772   // for any shared tear-down.
 773   this->smr_delete();
 774 }
 775 
 776 static void ensure_join(JavaThread* thread) {
 777   // We do not need to grab the Threads_lock, since we are operating on ourself.
 778   Handle threadObj(thread, thread->threadObj());
 779   assert(threadObj.not_null(), "java thread object must exist");
 780   ObjectLocker lock(threadObj, thread);
 781   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
 782   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
 783   // Clear the native thread instance - this makes isAlive return false and allows the join()
 784   // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
 785   // requirements.
 786   assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
 787   java_lang_Thread::release_set_thread(threadObj(), nullptr);
 788   lock.notify_all(thread);
 789   // Ignore pending exception, since we are exiting anyway
 790   thread->clear_pending_exception();
 791 }
 792 
 793 static bool is_daemon(oop threadObj) {
 794   return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
 795 }
 796 
 797 // For any new cleanup additions, please check to see if they need to be applied to
 798 // cleanup_failed_attach_current_thread as well.
 799 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
 800   assert(this == JavaThread::current(), "thread consistency check");
 801   assert(!is_exiting(), "should not be exiting or terminated already");
 802 
 803   elapsedTimer _timer_exit_phase1;
 804   elapsedTimer _timer_exit_phase2;
 805   elapsedTimer _timer_exit_phase3;
 806   elapsedTimer _timer_exit_phase4;
 807 
 808   if (log_is_enabled(Debug, os, thread, timer)) {
 809     _timer_exit_phase1.start();
 810   }
 811 
 812   HandleMark hm(this);
 813   Handle uncaught_exception(this, this->pending_exception());
 814   this->clear_pending_exception();
 815   Handle threadObj(this, this->threadObj());
 816   assert(threadObj.not_null(), "Java thread object should be created");
 817 
 818   if (!destroy_vm) {
 819     if (uncaught_exception.not_null()) {
 820       EXCEPTION_MARK;
 821       // Call method Thread.dispatchUncaughtException().
 822       Klass* thread_klass = vmClasses::Thread_klass();
 823       JavaValue result(T_VOID);
 824       JavaCalls::call_virtual(&result,
 825                               threadObj, thread_klass,
 826                               vmSymbols::dispatchUncaughtException_name(),
 827                               vmSymbols::throwable_void_signature(),
 828                               uncaught_exception,
 829                               THREAD);
 830       if (HAS_PENDING_EXCEPTION) {
 831         ResourceMark rm(this);
 832         jio_fprintf(defaultStream::error_stream(),
 833                     "\nException: %s thrown from the UncaughtExceptionHandler"
 834                     " in thread \"%s\"\n",
 835                     pending_exception()->klass()->external_name(),
 836                     name());
 837         CLEAR_PENDING_EXCEPTION;
 838       }
 839     }
 840 
 841     if (!is_Compiler_thread()) {
 842       // We have finished executing user-defined Java code and now have to do the
 843       // implementation specific clean-up by calling Thread.exit(). We prevent any
 844       // asynchronous exceptions from being delivered while in Thread.exit()
 845       // to ensure the clean-up is not corrupted.
 846       NoAsyncExceptionDeliveryMark _no_async(this);
 847 
 848       EXCEPTION_MARK;
 849       JavaValue result(T_VOID);
 850       Klass* thread_klass = vmClasses::Thread_klass();
 851       JavaCalls::call_virtual(&result,
 852                               threadObj, thread_klass,
 853                               vmSymbols::exit_method_name(),
 854                               vmSymbols::void_method_signature(),
 855                               THREAD);
 856       CLEAR_PENDING_EXCEPTION;
 857     }
 858 
 859     // notify JVMTI
 860     if (JvmtiExport::should_post_thread_life()) {
 861       JvmtiExport::post_thread_end(this);
 862     }
 863   } else {
 864     // before_exit() has already posted JVMTI THREAD_END events
 865   }
 866 
 867   // Cleanup any pending async exception now since we cannot access oops after
 868   // BarrierSet::barrier_set()->on_thread_detach() has been executed.
 869   if (has_async_exception_condition()) {
 870     handshake_state()->clean_async_exception_operation();
 871   }
 872 
 873   // The careful dance between thread suspension and exit is handled here.
 874   // Since we are in thread_in_vm state and suspension is done with handshakes,
 875   // we can just put in the exiting state and it will be correctly handled.
 876   // Also, no more async exceptions will be added to the queue after this point.
 877   set_terminated(_thread_exiting);
 878   ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
 879 
 880   if (log_is_enabled(Debug, os, thread, timer)) {
 881     _timer_exit_phase1.stop();
 882     _timer_exit_phase2.start();
 883   }
 884 
 885   // Capture daemon status before the thread is marked as terminated.
 886   bool daemon = is_daemon(threadObj());
 887 
 888   // Notify waiters on thread object. This has to be done after exit() is called
 889   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
 890   // group should have the destroyed bit set before waiters are notified).
 891   ensure_join(this);
 892   assert(!this->has_pending_exception(), "ensure_join should have cleared");
 893 
 894   if (log_is_enabled(Debug, os, thread, timer)) {
 895     _timer_exit_phase2.stop();
 896     _timer_exit_phase3.start();
 897   }
 898   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
 899   // held by this thread must be released. The spec does not distinguish
 900   // between JNI-acquired and regular Java monitors. We can only see
 901   // regular Java monitors here if monitor enter-exit matching is broken.
 902   //
 903   // ensure_join() ignores IllegalThreadStateExceptions, and so does
 904   // ObjectSynchronizer::release_monitors_owned_by_thread().
 905   if (exit_type == jni_detach) {
 906     // Sanity check even though JNI DetachCurrentThread() would have
 907     // returned JNI_ERR if there was a Java frame. JavaThread exit
 908     // should be done executing Java code by the time we get here.
 909     assert(!this->has_last_Java_frame(),
 910            "should not have a Java frame when detaching or exiting");
 911     ObjectSynchronizer::release_monitors_owned_by_thread(this);
 912     assert(!this->has_pending_exception(), "release_monitors should have cleared");
 913   }
 914 
 915   // Since above code may not release JNI monitors and if someone forgot to do an
 916   // JNI monitorexit, held count should be equal jni count.
 917   // Consider scan all object monitor for this owner if JNI count > 0 (at least on detach).
 918   assert(held_monitor_count() == jni_monitor_count(),
 919          "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
 920          held_monitor_count(), jni_monitor_count());
 921   if (CheckJNICalls && jni_monitor_count() > 0) {
 922     // We would like a fatal here, but due to we never checked this before there
 923     // is a lot of tests which breaks, even with an error log.
 924     log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
 925       exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
 926   }

 927 
 928   // These things needs to be done while we are still a Java Thread. Make sure that thread
 929   // is in a consistent state, in case GC happens
 930   JFR_ONLY(Jfr::on_thread_exit(this);)
 931 
 932   if (active_handles() != nullptr) {
 933     JNIHandleBlock* block = active_handles();
 934     set_active_handles(nullptr);
 935     JNIHandleBlock::release_block(block);
 936   }
 937 
 938   if (free_handle_block() != nullptr) {
 939     JNIHandleBlock* block = free_handle_block();
 940     set_free_handle_block(nullptr);
 941     JNIHandleBlock::release_block(block);
 942   }
 943 
 944   // These have to be removed while this is still a valid thread.
 945   _stack_overflow_state.remove_stack_guard_pages();
 946 
 947   if (UseTLAB) {
 948     tlab().retire();
 949   }
 950 
 951   if (JvmtiEnv::environments_might_exist()) {
 952     JvmtiExport::cleanup_thread(this);
 953   }
 954 
 955   // We need to cache the thread name for logging purposes below as once
 956   // we have called on_thread_detach this thread must not access any oops.
 957   char* thread_name = nullptr;
 958   if (log_is_enabled(Debug, os, thread, timer)) {
 959     ResourceMark rm(this);
 960     thread_name = os::strdup(name());
 961   }
 962 
 963   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
 964     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
 965     os::current_thread_id());
 966 
 967   if (log_is_enabled(Debug, os, thread, timer)) {
 968     _timer_exit_phase3.stop();
 969     _timer_exit_phase4.start();
 970   }
 971 
 972 #if INCLUDE_JVMCI
 973   if (JVMCICounterSize > 0) {
 974     if (jvmci_counters_include(this)) {
 975       for (int i = 0; i < JVMCICounterSize; i++) {
 976         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
 977       }
 978     }
 979   }
 980 #endif // INCLUDE_JVMCI
 981 
 982   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
 983   // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
 984   Threads::remove(this, daemon);
 985 
 986   if (log_is_enabled(Debug, os, thread, timer)) {
 987     _timer_exit_phase4.stop();
 988     log_debug(os, thread, timer)("name='%s'"
 989                                  ", exit-phase1=" JLONG_FORMAT
 990                                  ", exit-phase2=" JLONG_FORMAT
 991                                  ", exit-phase3=" JLONG_FORMAT
 992                                  ", exit-phase4=" JLONG_FORMAT,
 993                                  thread_name,
 994                                  _timer_exit_phase1.milliseconds(),
 995                                  _timer_exit_phase2.milliseconds(),
 996                                  _timer_exit_phase3.milliseconds(),
 997                                  _timer_exit_phase4.milliseconds());
 998     os::free(thread_name);
 999   }
1000 }
1001 
1002 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1003   if (active_handles() != nullptr) {
1004     JNIHandleBlock* block = active_handles();
1005     set_active_handles(nullptr);
1006     JNIHandleBlock::release_block(block);
1007   }
1008 
1009   if (free_handle_block() != nullptr) {
1010     JNIHandleBlock* block = free_handle_block();
1011     set_free_handle_block(nullptr);
1012     JNIHandleBlock::release_block(block);
1013   }
1014 
1015   // These have to be removed while this is still a valid thread.
1016   _stack_overflow_state.remove_stack_guard_pages();
1017 
1018   if (UseTLAB) {
1019     tlab().retire();
1020   }
1021 
1022   Threads::remove(this, is_daemon);
1023   this->smr_delete();
1024 }
1025 
1026 JavaThread* JavaThread::active() {
1027   Thread* thread = Thread::current();
1028   if (thread->is_Java_thread()) {
1029     return JavaThread::cast(thread);
1030   } else {
1031     assert(thread->is_VM_thread(), "this must be a vm thread");
1032     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1033     JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1034     return ret;
1035   }
1036 }
1037 
1038 bool JavaThread::is_lock_owned(address adr) const {
1039   assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1040   if (Thread::is_lock_owned(adr)) return true;
1041 
1042   for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
1043     if (chunk->contains(adr)) return true;
1044   }
1045 
1046   return false;
1047 }
1048 
1049 oop JavaThread::exception_oop() const {
1050   return Atomic::load(&_exception_oop);
1051 }
1052 
1053 void JavaThread::set_exception_oop(oop o) {
1054   Atomic::store(&_exception_oop, o);
1055 }
1056 
1057 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1058   chunk->set_next(monitor_chunks());
1059   set_monitor_chunks(chunk);
1060 }
1061 
1062 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1063   guarantee(monitor_chunks() != nullptr, "must be non empty");
1064   if (monitor_chunks() == chunk) {
1065     set_monitor_chunks(chunk->next());
1066   } else {
1067     MonitorChunk* prev = monitor_chunks();
1068     while (prev->next() != chunk) prev = prev->next();
1069     prev->set_next(chunk->next());
1070   }
1071 }
1072 
1073 void JavaThread::handle_special_runtime_exit_condition() {
1074   if (is_obj_deopt_suspend()) {
1075     frame_anchor()->make_walkable();
1076     wait_for_object_deoptimization();
1077   }
1078   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1079 }
1080 
1081 
1082 // Asynchronous exceptions support
1083 //
1084 void JavaThread::handle_async_exception(oop java_throwable) {
1085   assert(java_throwable != nullptr, "should have an _async_exception to throw");
1086   assert(!is_at_poll_safepoint(), "should have never called this method");
1087 
1088   if (has_last_Java_frame()) {
1089     frame f = last_frame();
1090     if (f.is_runtime_frame()) {
1091       // If the topmost frame is a runtime stub, then we are calling into
1092       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1093       // must deoptimize the caller before continuing, as the compiled exception
1094       // handler table may not be valid.
1095       RegisterMap reg_map(this,
1096                           RegisterMap::UpdateMap::skip,
1097                           RegisterMap::ProcessFrames::include,
1098                           RegisterMap::WalkContinuation::skip);
1099       frame compiled_frame = f.sender(&reg_map);
1100       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1101         Deoptimization::deoptimize(this, compiled_frame);
1102       }
1103     }
1104   }
1105 
1106   // We cannot call Exceptions::_throw(...) here because we cannot block
1107   set_pending_exception(java_throwable, __FILE__, __LINE__);
1108 
1109   clear_scopedValueBindings();
1110 
1111   LogTarget(Info, exceptions) lt;
1112   if (lt.is_enabled()) {
1113     ResourceMark rm;
1114     LogStream ls(lt);
1115     ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1116     if (has_last_Java_frame()) {
1117       frame f = last_frame();
1118       ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1119     }
1120     ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1121   }
1122 }
1123 
1124 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1125   // Do not throw asynchronous exceptions against the compiler thread
1126   // or if the thread is already exiting.
1127   if (!can_call_java() || is_exiting()) {
1128     delete aeh;
1129     return;
1130   }
1131 
1132   oop exception = aeh->exception();
1133   Handshake::execute(aeh, this);  // Install asynchronous handshake
1134 
1135   ResourceMark rm;
1136   if (log_is_enabled(Info, exceptions)) {
1137     log_info(exceptions)("Pending Async. exception installed of type: %s",
1138                          InstanceKlass::cast(exception->klass())->external_name());
1139   }
1140   // for AbortVMOnException flag
1141   Exceptions::debug_check_abort(exception->klass()->external_name());
1142 
1143   oop vt_oop = vthread();
1144   if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1145     // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1146     java_lang_Thread::set_interrupted(threadObj(), true);
1147     this->interrupt();
1148   }
1149 }
1150 
1151 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1152   AsyncExceptionHandshake* _aeh;
1153 public:
1154   InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1155     HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1156   ~InstallAsyncExceptionHandshake() {
1157     // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1158     delete _aeh;
1159   }
1160   void do_thread(Thread* thr) {
1161     JavaThread* target = JavaThread::cast(thr);
1162     target->install_async_exception(_aeh);
1163     _aeh = nullptr;
1164   }
1165 };
1166 
1167 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1168   OopHandle e(Universe::vm_global(), java_throwable);
1169   InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1170   Handshake::execute(&iaeh, target);
1171 }
1172 
1173 #if INCLUDE_JVMTI
1174 void JavaThread::set_is_in_VTMS_transition(bool val) {

1175   _is_in_VTMS_transition = val;
1176 }
1177 
1178 #ifdef ASSERT
1179 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1180   _is_VTMS_transition_disabler = val;
1181 }
1182 #endif
1183 #endif
1184 
1185 // External suspension mechanism.
1186 //
1187 // Guarantees on return (for a valid target thread):
1188 //   - Target thread will not execute any new bytecode.
1189 //   - Target thread will not enter any new monitors.
1190 //
1191 bool JavaThread::java_suspend() {
1192 #if INCLUDE_JVMTI
1193   // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1194   assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1195   assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1196 #endif
1197 
1198   guarantee(Thread::is_JavaThread_protected(/* target */ this),
1199             "target JavaThread is not protected in calling context.");
1200   return this->handshake_state()->suspend();
1201 }
1202 
1203 bool JavaThread::java_resume() {
1204   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1205             "missing ThreadsListHandle in calling context.");
1206   return this->handshake_state()->resume();
1207 }
1208 
1209 // Wait for another thread to perform object reallocation and relocking on behalf of
1210 // this thread. The current thread is required to change to _thread_blocked in order
1211 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1212 // handshake safe, the other thread can complete the handshake used to synchronize
1213 // with this thread and then perform the reallocation and relocking.
1214 // See EscapeBarrier::sync_and_suspend_*()
1215 
1216 void JavaThread::wait_for_object_deoptimization() {
1217   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1218   assert(this == Thread::current(), "invariant");
1219 
1220   bool spin_wait = os::is_MP();
1221   do {
1222     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1223     // Wait for object deoptimization if requested.
1224     if (spin_wait) {
1225       // A single deoptimization is typically very short. Microbenchmarks
1226       // showed 5% better performance when spinning.
1227       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1228       SpinYield spin(spin_limit);
1229       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1230         spin.wait();
1231       }
1232       // Spin just once
1233       spin_wait = false;
1234     } else {
1235       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1236       if (is_obj_deopt_suspend()) {
1237         ml.wait();
1238       }
1239     }
1240     // A handshake for obj. deoptimization suspend could have been processed so
1241     // we must check after processing.
1242   } while (is_obj_deopt_suspend());
1243 }
1244 
1245 #ifdef ASSERT
1246 // Verify the JavaThread has not yet been published in the Threads::list, and
1247 // hence doesn't need protection from concurrent access at this stage.
1248 void JavaThread::verify_not_published() {
1249   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1250   // since an unpublished JavaThread doesn't participate in the
1251   // Thread-SMR protocol for keeping a ThreadsList alive.
1252   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1253 }
1254 #endif
1255 
1256 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1257 // pending, when _suspend_flags is non-zero or when we need to process a stack
1258 // watermark. Also check for pending async exceptions (except unsafe access error).
1259 // Note only the native==>Java barriers can call this function when thread state
1260 // is _thread_in_native_trans.
1261 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1262   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1263   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1264 
1265   thread->set_thread_state(_thread_in_vm);
1266 
1267   // Enable WXWrite: called directly from interpreter native wrapper.
1268   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1269 
1270   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1271 
1272   // After returning from native, it could be that the stack frames are not
1273   // yet safe to use. We catch such situations in the subsequent stack watermark
1274   // barrier, which will trap unsafe stack frames.
1275   StackWatermarkSet::before_unwind(thread);
1276 }
1277 
1278 #ifndef PRODUCT
1279 // Deoptimization
1280 // Function for testing deoptimization
1281 void JavaThread::deoptimize() {
1282   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1283   bool deopt = false;           // Dump stack only if a deopt actually happens.
1284   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1285   // Iterate over all frames in the thread and deoptimize
1286   for (; !fst.is_done(); fst.next()) {
1287     if (fst.current()->can_be_deoptimized()) {
1288 
1289       if (only_at) {
1290         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1291         // consists of comma or carriage return separated numbers so
1292         // search for the current bci in that string.
1293         address    pc = fst.current()->pc();
1294         nmethod*   nm = fst.current()->cb()->as_nmethod();
1295         ScopeDesc* sd = nm->scope_desc_at(pc);
1296         char buffer[8];
1297         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1298         size_t len = strlen(buffer);
1299         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1300         while (found != nullptr) {
1301           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1302               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1303             // Check that the bci found is bracketed by terminators.
1304             break;
1305           }
1306           found = strstr(found + 1, buffer);
1307         }
1308         if (!found) {
1309           continue;
1310         }
1311       }
1312 
1313       if (DebugDeoptimization && !deopt) {
1314         deopt = true; // One-time only print before deopt
1315         tty->print_cr("[BEFORE Deoptimization]");
1316         trace_frames();
1317         trace_stack();
1318       }
1319       Deoptimization::deoptimize(this, *fst.current());
1320     }
1321   }
1322 
1323   if (DebugDeoptimization && deopt) {
1324     tty->print_cr("[AFTER Deoptimization]");
1325     trace_frames();
1326   }
1327 }
1328 
1329 
1330 // Make zombies
1331 void JavaThread::make_zombies() {
1332   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1333     if (fst.current()->can_be_deoptimized()) {
1334       // it is a Java nmethod
1335       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1336       assert(nm != nullptr, "did not find nmethod");
1337       nm->make_not_entrant();
1338     }
1339   }
1340 }
1341 #endif // PRODUCT
1342 
1343 
1344 void JavaThread::deoptimize_marked_methods() {
1345   if (!has_last_Java_frame()) return;
1346   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1347   for (; !fst.is_done(); fst.next()) {
1348     if (fst.current()->should_be_deoptimized()) {
1349       Deoptimization::deoptimize(this, *fst.current());
1350     }
1351   }
1352 }
1353 
1354 #ifdef ASSERT
1355 void JavaThread::verify_frame_info() {
1356   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1357          (has_last_Java_frame() && java_call_counter() > 0),
1358          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1359          has_last_Java_frame() ? "true" : "false", java_call_counter());
1360 }
1361 #endif
1362 
1363 // Push on a new block of JNI handles.
1364 void JavaThread::push_jni_handle_block() {
1365   // Allocate a new block for JNI handles.
1366   // Inlined code from jni_PushLocalFrame()
1367   JNIHandleBlock* old_handles = active_handles();
1368   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1369   assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1370   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1371   set_active_handles(new_handles);
1372 }
1373 
1374 // Pop off the current block of JNI handles.
1375 void JavaThread::pop_jni_handle_block() {
1376   // Release our JNI handle block
1377   JNIHandleBlock* old_handles = active_handles();
1378   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1379   assert(new_handles != nullptr, "should never set active handles to null");
1380   set_active_handles(new_handles);
1381   old_handles->set_pop_frame_link(nullptr);
1382   JNIHandleBlock::release_block(old_handles, this);
1383 }
1384 
1385 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1386   // Verify that the deferred card marks have been flushed.
1387   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1388 
1389   // Traverse the GCHandles
1390   Thread::oops_do_no_frames(f, cf);
1391 
1392   if (active_handles() != nullptr) {
1393     active_handles()->oops_do(f);
1394   }
1395 
1396   DEBUG_ONLY(verify_frame_info();)
1397 
1398   if (has_last_Java_frame()) {
1399     // Traverse the monitor chunks
1400     for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
1401       chunk->oops_do(f);
1402     }
1403   }
1404 
1405   assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1406   // If we have deferred set_locals there might be oops waiting to be
1407   // written
1408   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1409   if (list != nullptr) {
1410     for (int i = 0; i < list->length(); i++) {
1411       list->at(i)->oops_do(f);
1412     }
1413   }
1414 
1415   // Traverse instance variables at the end since the GC may be moving things
1416   // around using this function
1417   f->do_oop((oop*) &_vm_result);
1418   f->do_oop((oop*) &_exception_oop);
1419 #if INCLUDE_JVMCI
1420   f->do_oop((oop*) &_jvmci_reserved_oop0);
1421 #endif
1422 
1423   if (jvmti_thread_state() != nullptr) {
1424     jvmti_thread_state()->oops_do(f, cf);
1425   }
1426 
1427   // The continuation oops are really on the stack. But there is typically at most
1428   // one of those per thread, so we handle them here in the oops_do_no_frames part
1429   // so that we don't have to sprinkle as many stack watermark checks where these
1430   // oops are used. We just need to make sure the thread has started processing.
1431   ContinuationEntry* entry = _cont_entry;
1432   while (entry != nullptr) {
1433     f->do_oop((oop*)entry->cont_addr());
1434     f->do_oop((oop*)entry->chunk_addr());
1435     entry = entry->parent();
1436   }
1437 
1438   if (LockingMode == LM_LIGHTWEIGHT) {
1439     lock_stack().oops_do(f);
1440   }
1441 }
1442 
1443 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1444   if (!has_last_Java_frame()) {
1445     return;
1446   }
1447   // Finish any pending lazy GC activity for the frames
1448   StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1449   // Traverse the execution stack
1450   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1451     fst.current()->oops_do(f, cf, fst.register_map());
1452   }
1453 }
1454 
1455 #ifdef ASSERT
1456 void JavaThread::verify_states_for_handshake() {
1457   // This checks that the thread has a correct frame state during a handshake.
1458   verify_frame_info();
1459 }
1460 #endif
1461 
1462 void JavaThread::nmethods_do(NMethodClosure* cf) {
1463   DEBUG_ONLY(verify_frame_info();)
1464   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1465 
1466   if (has_last_Java_frame()) {
1467     // Traverse the execution stack
1468     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1469       fst.current()->nmethod_do(cf);
1470     }
1471   }
1472 
1473   if (jvmti_thread_state() != nullptr) {
1474     jvmti_thread_state()->nmethods_do(cf);
1475   }
1476 }
1477 
1478 void JavaThread::metadata_do(MetadataClosure* f) {
1479   if (has_last_Java_frame()) {
1480     // Traverse the execution stack to call f() on the methods in the stack
1481     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1482       fst.current()->metadata_do(f);
1483     }
1484   } else if (is_Compiler_thread()) {
1485     // need to walk ciMetadata in current compile tasks to keep alive.
1486     CompilerThread* ct = (CompilerThread*)this;
1487     if (ct->env() != nullptr) {
1488       ct->env()->metadata_do(f);
1489     }
1490     CompileTask* task = ct->task();
1491     if (task != nullptr) {
1492       task->metadata_do(f);
1493     }
1494   }
1495 }
1496 
1497 // Printing
1498 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1499   switch (_thread_state) {
1500   case _thread_uninitialized:     return "_thread_uninitialized";
1501   case _thread_new:               return "_thread_new";
1502   case _thread_new_trans:         return "_thread_new_trans";
1503   case _thread_in_native:         return "_thread_in_native";
1504   case _thread_in_native_trans:   return "_thread_in_native_trans";
1505   case _thread_in_vm:             return "_thread_in_vm";
1506   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1507   case _thread_in_Java:           return "_thread_in_Java";
1508   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1509   case _thread_blocked:           return "_thread_blocked";
1510   case _thread_blocked_trans:     return "_thread_blocked_trans";
1511   default:                        return "unknown thread state";
1512   }
1513 }
1514 
1515 void JavaThread::print_thread_state_on(outputStream *st) const {
1516   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1517 }
1518 
1519 // Called by Threads::print() for VM_PrintThreads operation
1520 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1521   st->print_raw("\"");
1522   st->print_raw(name());
1523   st->print_raw("\" ");
1524   oop thread_oop = threadObj();
1525   if (thread_oop != nullptr) {
1526     st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1527     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
1528     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1529   }
1530   Thread::print_on(st, print_extended_info);
1531   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1532   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1533   if (thread_oop != nullptr) {
1534     if (is_vthread_mounted()) {
1535       oop vt = vthread();
1536       assert(vt != nullptr, "");
1537       st->print_cr("   Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1538     } else {
1539       st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1540     }
1541   }
1542 #ifndef PRODUCT
1543   _safepoint_state->print_on(st);
1544 #endif // PRODUCT
1545   if (is_Compiler_thread()) {
1546     CompileTask *task = ((CompilerThread*)this)->task();
1547     if (task != nullptr) {
1548       st->print("   Compiling: ");
1549       task->print(st, nullptr, true, false);
1550     } else {
1551       st->print("   No compile task");
1552     }
1553     st->cr();
1554   }
1555 }
1556 
1557 void JavaThread::print() const { print_on(tty); }
1558 
1559 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1560   st->print("%s", get_thread_name_string(buf, buflen));
1561 }
1562 
1563 // Called by fatal error handler. The difference between this and
1564 // JavaThread::print() is that we can't grab lock or allocate memory.
1565 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1566   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1567   Thread* current = Thread::current_or_null_safe();
1568   assert(current != nullptr, "cannot be called by a detached thread");
1569   st->fill_to(60);
1570   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1571     // Only access threadObj() if current thread is not a JavaThread
1572     // or if it is a JavaThread that can safely access oops.
1573     oop thread_obj = threadObj();
1574     if (thread_obj != nullptr) {
1575       st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : "       ");
1576     }
1577   }
1578   st->print(" [");
1579   st->print("%s", _get_thread_state_name(_thread_state));
1580   if (osthread()) {
1581     st->print(", id=%d", osthread()->thread_id());
1582   }
1583   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1584             p2i(stack_end()), p2i(stack_base()),
1585             PROPERFMTARGS(stack_size()));
1586   st->print("]");
1587 
1588   ThreadsSMRSupport::print_info_on(this, st);
1589   return;
1590 }
1591 
1592 
1593 // Verification
1594 
1595 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1596   // ignore if there is no stack
1597   if (!has_last_Java_frame()) return;
1598   // traverse the stack frames. Starts from top frame.
1599   for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1600     frame* fr = fst.current();
1601     f(fr, fst.register_map());
1602   }
1603 }
1604 
1605 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1606 
1607 void JavaThread::verify() {
1608   // Verify oops in the thread.
1609   oops_do(&VerifyOopClosure::verify_oop, nullptr);
1610 
1611   // Verify the stack frames.
1612   frames_do(frame_verify);
1613 }
1614 
1615 // CR 6300358 (sub-CR 2137150)
1616 // Most callers of this method assume that it can't return null but a
1617 // thread may not have a name whilst it is in the process of attaching to
1618 // the VM - see CR 6412693, and there are places where a JavaThread can be
1619 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1620 // if vm exit occurs during initialization). These cases can all be accounted
1621 // for such that this method never returns null.
1622 const char* JavaThread::name() const  {
1623   if (Thread::is_JavaThread_protected(/* target */ this)) {
1624     // The target JavaThread is protected so get_thread_name_string() is safe:
1625     return get_thread_name_string();
1626   }
1627 
1628   // The target JavaThread is not protected so we return the default:
1629   return Thread::name();
1630 }
1631 
1632 // Like name() but doesn't include the protection check. This must only be
1633 // called when it is known to be safe, even though the protection check can't tell
1634 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1635 const char* JavaThread::name_raw() const  {
1636   return get_thread_name_string();
1637 }
1638 
1639 // Returns a non-null representation of this thread's name, or a suitable
1640 // descriptive string if there is no set name.
1641 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1642   const char* name_str;
1643 #ifdef ASSERT
1644   Thread* current = Thread::current_or_null_safe();
1645   assert(current != nullptr, "cannot be called by a detached thread");
1646   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1647     // Only access threadObj() if current thread is not a JavaThread
1648     // or if it is a JavaThread that can safely access oops.
1649 #endif
1650     oop thread_obj = threadObj();
1651     if (thread_obj != nullptr) {
1652       oop name = java_lang_Thread::name(thread_obj);
1653       if (name != nullptr) {
1654         if (buf == nullptr) {
1655           name_str = java_lang_String::as_utf8_string(name);
1656         } else {
1657           name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1658         }
1659       } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1660         name_str = "<no-name - thread is attaching>";
1661       } else {
1662         name_str = "<un-named>";
1663       }
1664     } else {
1665       name_str = Thread::name();
1666     }
1667 #ifdef ASSERT
1668   } else {
1669     // Current JavaThread has exited...
1670     if (current == this) {
1671       // ... and is asking about itself:
1672       name_str = "<no-name - current JavaThread has exited>";
1673     } else {
1674       // ... and it can't safely determine this JavaThread's name so
1675       // use the default thread name.
1676       name_str = Thread::name();
1677     }
1678   }
1679 #endif
1680   assert(name_str != nullptr, "unexpected null thread name");
1681   return name_str;
1682 }
1683 
1684 // Helper to extract the name from the thread oop for logging.
1685 const char* JavaThread::name_for(oop thread_obj) {
1686   assert(thread_obj != nullptr, "precondition");
1687   oop name = java_lang_Thread::name(thread_obj);
1688   const char* name_str;
1689   if (name != nullptr) {
1690     name_str = java_lang_String::as_utf8_string(name);
1691   } else {
1692     name_str = "<un-named>";
1693   }
1694   return name_str;
1695 }
1696 
1697 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1698 
1699   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1700   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1701   // Link Java Thread object <-> C++ Thread
1702 
1703   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1704   // and put it into a new Handle.  The Handle "thread_oop" can then
1705   // be used to pass the C++ thread object to other methods.
1706 
1707   // Set the Java level thread object (jthread) field of the
1708   // new thread (a JavaThread *) to C++ thread object using the
1709   // "thread_oop" handle.
1710 
1711   // Set the thread field (a JavaThread *) of the
1712   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1713 
1714   Handle thread_oop(Thread::current(),
1715                     JNIHandles::resolve_non_null(jni_thread));
1716   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1717          "must be initialized");
1718   set_threadOopHandles(thread_oop());

1719 
1720   if (prio == NoPriority) {
1721     prio = java_lang_Thread::priority(thread_oop());
1722     assert(prio != NoPriority, "A valid priority should be present");
1723   }
1724 
1725   // Push the Java priority down to the native thread; needs Threads_lock
1726   Thread::set_priority(this, prio);
1727 
1728   // Add the new thread to the Threads list and set it in motion.
1729   // We must have threads lock in order to call Threads::add.
1730   // It is crucial that we do not block before the thread is
1731   // added to the Threads list for if a GC happens, then the java_thread oop
1732   // will not be visited by GC.
1733   Threads::add(this);
1734   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1735   // on a ThreadsList. We don't want to wait for the release when the
1736   // Theads_lock is dropped somewhere in the caller since the JavaThread*
1737   // is already visible to JVM/TI via the ThreadsList.
1738   java_lang_Thread::release_set_thread(thread_oop(), this);
1739 }
1740 
1741 oop JavaThread::current_park_blocker() {
1742   // Support for JSR-166 locks
1743   oop thread_oop = threadObj();
1744   if (thread_oop != nullptr) {
1745     return java_lang_Thread::park_blocker(thread_oop);
1746   }
1747   return nullptr;
1748 }
1749 
1750 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1751 // This is the external format, selecting the platform or vthread
1752 // as applicable, and allowing for a native-only stack.
1753 void JavaThread::print_jni_stack() {
1754   assert(this == JavaThread::current(), "Can't print stack of other threads");
1755   if (!has_last_Java_frame()) {
1756     ResourceMark rm(this);
1757     char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1758     if (buf == nullptr) {
1759       tty->print_cr("Unable to print native stack - out of memory");
1760       return;
1761     }
1762     address lastpc = nullptr;
1763     if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) {
1764       // We have printed the native stack in platform-specific code,
1765       // so nothing else to do in this case.
1766     } else {
1767       frame f = os::current_frame();
1768       VMError::print_native_stack(tty, f, this, true /*print_source_info */,
1769                                   -1 /* max stack */, buf, O_BUFLEN);
1770     }
1771   } else {
1772     print_active_stack_on(tty);
1773   }
1774 }
1775 
1776 void JavaThread::print_stack_on(outputStream* st) {
1777   if (!has_last_Java_frame()) return;
1778 
1779   Thread* current_thread = Thread::current();
1780   ResourceMark rm(current_thread);
1781   HandleMark hm(current_thread);
1782 
1783   RegisterMap reg_map(this,
1784                       RegisterMap::UpdateMap::include,
1785                       RegisterMap::ProcessFrames::include,
1786                       RegisterMap::WalkContinuation::skip);
1787   vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
1788   int count = 0;
1789   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1790     if (f->is_java_frame()) {
1791       javaVFrame* jvf = javaVFrame::cast(f);
1792       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1793 
1794       // Print out lock information
1795       if (JavaMonitorsInStackTrace) {
1796         jvf->print_lock_info_on(st, count);
1797       }
1798     } else {
1799       // Ignore non-Java frames
1800     }
1801 
1802     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1803     count++;
1804     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1805   }
1806 }
1807 
1808 void JavaThread::print_vthread_stack_on(outputStream* st) {
1809   assert(is_vthread_mounted(), "Caller should have checked this");
1810   assert(has_last_Java_frame(), "must be");
1811 
1812   Thread* current_thread = Thread::current();
1813   ResourceMark rm(current_thread);
1814   HandleMark hm(current_thread);
1815 
1816   RegisterMap reg_map(this,
1817                       RegisterMap::UpdateMap::include,
1818                       RegisterMap::ProcessFrames::include,
1819                       RegisterMap::WalkContinuation::include);
1820   ContinuationEntry* cont_entry = last_continuation();
1821   vframe* start_vf = last_java_vframe(&reg_map);
1822   int count = 0;
1823   for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1824     // Watch for end of vthread stack
1825     if (Continuation::is_continuation_enterSpecial(f->fr())) {
1826       assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1827       if (cont_entry->is_virtual_thread()) {
1828         break;
1829       }
1830       cont_entry = cont_entry->parent();
1831     }
1832     if (f->is_java_frame()) {
1833       javaVFrame* jvf = javaVFrame::cast(f);
1834       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1835 
1836       // Print out lock information
1837       if (JavaMonitorsInStackTrace) {
1838         jvf->print_lock_info_on(st, count);
1839       }
1840     } else {
1841       // Ignore non-Java frames
1842     }
1843 
1844     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1845     count++;
1846     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1847   }
1848 }
1849 
1850 void JavaThread::print_active_stack_on(outputStream* st) {
1851   if (is_vthread_mounted()) {
1852     print_vthread_stack_on(st);
1853   } else {
1854     print_stack_on(st);
1855   }
1856 }
1857 
1858 #if INCLUDE_JVMTI
1859 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1860 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1861   set_jvmti_vthread(thread_oop);
1862 
1863   // unbind current JvmtiThreadState from JavaThread
1864   JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1865 
1866   // bind new JvmtiThreadState to JavaThread
1867   JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1868 
1869   return jvmti_thread_state();
1870 }
1871 #endif
1872 
1873 // JVMTI PopFrame support
1874 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1875   assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1876   if (in_bytes(size_in_bytes) != 0) {
1877     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1878     _popframe_preserved_args_size = in_bytes(size_in_bytes);
1879     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1880   }
1881 }
1882 
1883 void* JavaThread::popframe_preserved_args() {
1884   return _popframe_preserved_args;
1885 }
1886 
1887 ByteSize JavaThread::popframe_preserved_args_size() {
1888   return in_ByteSize(_popframe_preserved_args_size);
1889 }
1890 
1891 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1892   int sz = in_bytes(popframe_preserved_args_size());
1893   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1894   return in_WordSize(sz / wordSize);
1895 }
1896 
1897 void JavaThread::popframe_free_preserved_args() {
1898   assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1899   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1900   _popframe_preserved_args = nullptr;
1901   _popframe_preserved_args_size = 0;
1902 }
1903 
1904 #ifndef PRODUCT
1905 
1906 void JavaThread::trace_frames() {
1907   tty->print_cr("[Describe stack]");
1908   int frame_no = 1;
1909   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1910     tty->print("  %d. ", frame_no++);
1911     fst.current()->print_value_on(tty, this);
1912     tty->cr();
1913   }
1914 }
1915 
1916 class PrintAndVerifyOopClosure: public OopClosure {
1917  protected:
1918   template <class T> inline void do_oop_work(T* p) {
1919     oop obj = RawAccess<>::oop_load(p);
1920     if (obj == nullptr) return;
1921     tty->print(INTPTR_FORMAT ": ", p2i(p));
1922     if (oopDesc::is_oop_or_null(obj)) {
1923       if (obj->is_objArray()) {
1924         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1925       } else {
1926         obj->print();
1927       }
1928     } else {
1929       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1930     }
1931     tty->cr();
1932   }
1933  public:
1934   virtual void do_oop(oop* p) { do_oop_work(p); }
1935   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
1936 };
1937 
1938 #ifdef ASSERT
1939 // Print or validate the layout of stack frames
1940 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1941   ResourceMark rm;
1942   PreserveExceptionMark pm(this);
1943   FrameValues values;
1944   int frame_no = 0;
1945   for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1946     fst.current()->describe(values, ++frame_no, fst.register_map());
1947     if (depth == frame_no) break;
1948   }
1949   Continuation::describe(values);
1950   if (validate_only) {
1951     values.validate();
1952   } else {
1953     tty->print_cr("[Describe stack layout]");
1954     values.print(this);
1955   }
1956 }
1957 #endif
1958 
1959 void JavaThread::trace_stack_from(vframe* start_vf) {
1960   ResourceMark rm;
1961   int vframe_no = 1;
1962   for (vframe* f = start_vf; f; f = f->sender()) {
1963     if (f->is_java_frame()) {
1964       javaVFrame::cast(f)->print_activation(vframe_no++);
1965     } else {
1966       f->print();
1967     }
1968     if (vframe_no > StackPrintLimit) {
1969       tty->print_cr("...<more frames>...");
1970       return;
1971     }
1972   }
1973 }
1974 
1975 
1976 void JavaThread::trace_stack() {
1977   if (!has_last_Java_frame()) return;
1978   Thread* current_thread = Thread::current();
1979   ResourceMark rm(current_thread);
1980   HandleMark hm(current_thread);
1981   RegisterMap reg_map(this,
1982                       RegisterMap::UpdateMap::include,
1983                       RegisterMap::ProcessFrames::include,
1984                       RegisterMap::WalkContinuation::skip);
1985   trace_stack_from(last_java_vframe(&reg_map));
1986 }
1987 
1988 
1989 #endif // PRODUCT
1990 
1991 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
1992 #ifdef SUPPORT_MONITOR_COUNT
1993   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count);
1994   _held_monitor_count += i;
1995   if (jni) {
1996     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count);
1997     _jni_monitor_count += i;
1998   }
1999 #endif
2000 }
2001 
2002 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2003 #ifdef SUPPORT_MONITOR_COUNT
2004   _held_monitor_count -= i;
2005   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count);
2006   if (jni) {
2007     _jni_monitor_count -= i;
2008     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count);
2009   }
2010 #endif
2011 }
2012 
2013 frame JavaThread::vthread_last_frame() {
2014   assert (is_vthread_mounted(), "Virtual thread not mounted");
2015   return last_frame();
2016 }
2017 
2018 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2019   const ContinuationEntry* entry = vthread_continuation();
2020   guarantee (entry != nullptr, "Not a carrier thread");
2021   frame f = entry->to_frame();
2022   if (reg_map->process_frames()) {
2023     entry->flush_stack_processing(this);
2024   }
2025   entry->update_register_map(reg_map);
2026   return f.sender(reg_map);
2027 }
2028 
2029 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2030   return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2031 }
2032 
2033 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2034   assert(reg_map != nullptr, "a map must be given");
2035   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2036     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2037   }
2038   return nullptr;
2039 }
2040 
2041 Klass* JavaThread::security_get_caller_class(int depth) {
2042   ResetNoHandleMark rnhm;
2043   HandleMark hm(Thread::current());
2044 
2045   vframeStream vfst(this);
2046   vfst.security_get_caller_frame(depth);
2047   if (!vfst.at_end()) {
2048     return vfst.method()->method_holder();
2049   }
2050   return nullptr;
2051 }
2052 
2053 // Internal convenience function for millisecond resolution sleeps.
2054 bool JavaThread::sleep(jlong millis) {
2055   jlong nanos;
2056   if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2057     // Conversion to nanos would overflow, saturate at max
2058     nanos = max_jlong;
2059   } else {
2060     nanos = millis * NANOUNITS_PER_MILLIUNIT;
2061   }
2062   return sleep_nanos(nanos);
2063 }
2064 
2065 // java.lang.Thread.sleep support
2066 // Returns true if sleep time elapsed as expected, and false
2067 // if the thread was interrupted.
2068 bool JavaThread::sleep_nanos(jlong nanos) {
2069   assert(this == Thread::current(),  "thread consistency check");
2070   assert(nanos >= 0, "nanos are in range");
2071 
2072   ParkEvent * const slp = this->_SleepEvent;
2073   // Because there can be races with thread interruption sending an unpark()
2074   // to the event, we explicitly reset it here to avoid an immediate return.
2075   // The actual interrupt state will be checked before we park().
2076   slp->reset();
2077   // Thread interruption establishes a happens-before ordering in the
2078   // Java Memory Model, so we need to ensure we synchronize with the
2079   // interrupt state.
2080   OrderAccess::fence();
2081 
2082   jlong prevtime = os::javaTimeNanos();
2083 
2084   jlong nanos_remaining = nanos;
2085 
2086   for (;;) {
2087     // interruption has precedence over timing out
2088     if (this->is_interrupted(true)) {
2089       return false;
2090     }
2091 
2092     if (nanos_remaining <= 0) {
2093       return true;
2094     }
2095 
2096     {
2097       ThreadBlockInVM tbivm(this);
2098       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2099       slp->park_nanos(nanos_remaining);
2100     }
2101 
2102     // Update elapsed time tracking
2103     jlong newtime = os::javaTimeNanos();
2104     if (newtime - prevtime < 0) {
2105       // time moving backwards, should only happen if no monotonic clock
2106       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2107       assert(false,
2108              "unexpected time moving backwards detected in JavaThread::sleep()");
2109     } else {
2110       nanos_remaining -= (newtime - prevtime);
2111     }
2112     prevtime = newtime;
2113   }
2114 }
2115 
2116 // Last thread running calls java.lang.Shutdown.shutdown()
2117 void JavaThread::invoke_shutdown_hooks() {
2118   HandleMark hm(this);
2119 
2120   // We could get here with a pending exception, if so clear it now.
2121   if (this->has_pending_exception()) {
2122     this->clear_pending_exception();
2123   }
2124 
2125   EXCEPTION_MARK;
2126   Klass* shutdown_klass =
2127     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2128                                       THREAD);
2129   if (shutdown_klass != nullptr) {
2130     // SystemDictionary::resolve_or_null will return null if there was
2131     // an exception.  If we cannot load the Shutdown class, just don't
2132     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
2133     // won't be run.  Note that if a shutdown hook was registered,
2134     // the Shutdown class would have already been loaded
2135     // (Runtime.addShutdownHook will load it).
2136     JavaValue result(T_VOID);
2137     JavaCalls::call_static(&result,
2138                            shutdown_klass,
2139                            vmSymbols::shutdown_name(),
2140                            vmSymbols::void_method_signature(),
2141                            THREAD);
2142   }
2143   CLEAR_PENDING_EXCEPTION;
2144 }
2145 
2146 #ifndef PRODUCT
2147 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2148    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2149 }
2150 #endif
2151 
2152 // Helper function to create the java.lang.Thread object for a
2153 // VM-internal thread. The thread will have the given name, and be
2154 // a member of the "system" ThreadGroup.
2155 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2156   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2157 
2158   // Initialize thread_oop to put it into the system threadGroup.
2159   // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2160   Handle thread_group(THREAD, Universe::system_thread_group());
2161   Handle thread_oop =
2162     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2163                                       vmSymbols::threadgroup_string_void_signature(),
2164                                       thread_group,
2165                                       string,
2166                                       CHECK_NH);
2167 
2168   return thread_oop;
2169 }
2170 
2171 // Starts the target JavaThread as a daemon of the given priority, and
2172 // bound to the given java.lang.Thread instance.
2173 // The Threads_lock is held for the duration.
2174 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2175                                        Handle thread_oop, ThreadPriority prio) {
2176 
2177   assert(target->osthread() != nullptr, "target thread is not properly initialized");
2178 
2179   MutexLocker mu(current, Threads_lock);
2180 
2181   // Initialize the fields of the thread_oop first.
2182   if (prio != NoPriority) {
2183     java_lang_Thread::set_priority(thread_oop(), prio);
2184     // Note: we don't call os::set_priority here. Possibly we should,
2185     // else all threads should call it themselves when they first run.
2186   }
2187 
2188   java_lang_Thread::set_daemon(thread_oop());
2189 
2190   // Now bind the thread_oop to the target JavaThread.
2191   target->set_threadOopHandles(thread_oop());

2192 
2193   Threads::add(target); // target is now visible for safepoint/handshake
2194   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2195   // on a ThreadsList. We don't want to wait for the release when the
2196   // Theads_lock is dropped when the 'mu' destructor is run since the
2197   // JavaThread* is already visible to JVM/TI via the ThreadsList.
2198 
2199   assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2200   java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2201   Thread::start(target);
2202 }
2203 
2204 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2205   // At this point it may be possible that no osthread was created for the
2206   // JavaThread due to lack of resources. However, since this must work
2207   // for critical system threads just check and abort if this fails.
2208   if (thread->osthread() == nullptr) {
2209     // This isn't really an OOM condition, but historically this is what
2210     // we report.
2211     vm_exit_during_initialization("java.lang.OutOfMemoryError",
2212                                   os::native_thread_creation_failed_msg());
2213   }
2214 }
2215 
2216 void JavaThread::pretouch_stack() {
2217   // Given an established java thread stack with usable area followed by
2218   // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2219   // from the current frame down to the start of the shadow zone.
2220   const address end = _stack_overflow_state.shadow_zone_safe_limit();
2221   if (is_in_full_stack(end)) {
2222     char* p1 = (char*) alloca(1);
2223     address here = (address) &p1;
2224     if (is_in_full_stack(here) && here > end) {
2225       size_t to_alloc = here - end;
2226       char* p2 = (char*) alloca(to_alloc);
2227       log_trace(os, thread)("Pretouching thread stack from " PTR_FORMAT " to " PTR_FORMAT ".",
2228                             p2i(p2), p2i(end));
2229       os::pretouch_memory(p2, p2 + to_alloc,
2230                           NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2231     }
2232   }
2233 }
2234 
2235 // Deferred OopHandle release support.
2236 
2237 class OopHandleList : public CHeapObj<mtInternal> {
2238   static const int _count = 4;
2239   OopHandle _handles[_count];
2240   OopHandleList* _next;
2241   int _index;
2242  public:
2243   OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2244   void add(OopHandle h) {
2245     assert(_index < _count, "too many additions");
2246     _handles[_index++] = h;
2247   }
2248   ~OopHandleList() {
2249     assert(_index == _count, "usage error");
2250     for (int i = 0; i < _index; i++) {
2251       _handles[i].release(JavaThread::thread_oop_storage());
2252     }
2253   }
2254   OopHandleList* next() const { return _next; }
2255 };
2256 
2257 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2258 
2259 // Called by the ServiceThread to do the work of releasing
2260 // the OopHandles.
2261 void JavaThread::release_oop_handles() {
2262   OopHandleList* list;
2263   {
2264     MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2265     list = _oop_handle_list;
2266     _oop_handle_list = nullptr;
2267   }
2268   assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2269 
2270   while (list != nullptr) {
2271     OopHandleList* l = list;
2272     list = l->next();
2273     delete l;
2274   }
2275 }
2276 
2277 // Add our OopHandles for later release.
2278 void JavaThread::add_oop_handles_for_release() {
2279   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2280   OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2281   new_head->add(_threadObj);
2282   new_head->add(_vthread);
2283   new_head->add(_jvmti_vthread);
2284   new_head->add(_scopedValueCache);
2285   _oop_handle_list = new_head;
2286   Service_lock->notify_all();
2287 }
--- EOF ---