1 /*
   2  * Copyright (c) 1997, 2021, 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 "jvm.h"
  28 #include "cds/dynamicArchive.hpp"
  29 #include "cds/metaspaceShared.hpp"
  30 #include "classfile/classLoader.hpp"
  31 #include "classfile/javaClasses.hpp"
  32 #include "classfile/javaThreadStatus.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmClasses.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "code/codeCache.hpp"
  37 #include "code/scopeDesc.hpp"
  38 #include "compiler/compileBroker.hpp"
  39 #include "compiler/compileTask.hpp"
  40 #include "compiler/compilerThread.hpp"
  41 #include "gc/shared/barrierSet.hpp"
  42 #include "gc/shared/collectedHeap.hpp"
  43 #include "gc/shared/gcId.hpp"
  44 #include "gc/shared/gcLocker.inline.hpp"
  45 #include "gc/shared/gcVMOperations.hpp"
  46 #include "gc/shared/oopStorage.hpp"
  47 #include "gc/shared/oopStorageSet.hpp"
  48 #include "gc/shared/stringdedup/stringDedup.hpp"
  49 #include "gc/shared/tlab_globals.hpp"
  50 #include "interpreter/interpreter.hpp"
  51 #include "interpreter/linkResolver.hpp"
  52 #include "interpreter/oopMapCache.hpp"
  53 #include "jfr/jfrEvents.hpp"
  54 #include "jvmtifiles/jvmtiEnv.hpp"
  55 #include "logging/log.hpp"
  56 #include "logging/logAsyncWriter.hpp"
  57 #include "logging/logConfiguration.hpp"
  58 #include "logging/logStream.hpp"
  59 #include "memory/allocation.inline.hpp"
  60 #include "memory/iterator.hpp"
  61 #include "memory/oopFactory.hpp"
  62 #include "memory/resourceArea.hpp"
  63 #include "memory/universe.hpp"
  64 #include "oops/access.inline.hpp"
  65 #include "oops/instanceKlass.hpp"
  66 #include "oops/klass.inline.hpp"
  67 #include "oops/objArrayOop.hpp"
  68 #include "oops/oop.inline.hpp"
  69 #include "oops/oopHandle.inline.hpp"
  70 #include "oops/symbol.hpp"
  71 #include "oops/typeArrayOop.inline.hpp"
  72 #include "oops/verifyOopClosure.hpp"
  73 #include "prims/jvm_misc.hpp"
  74 #include "prims/jvmtiDeferredUpdates.hpp"
  75 #include "prims/jvmtiExport.hpp"
  76 #include "prims/jvmtiThreadState.hpp"
  77 #include "runtime/arguments.hpp"
  78 #include "runtime/atomic.hpp"
  79 #include "runtime/biasedLocking.hpp"
  80 #include "runtime/fieldDescriptor.inline.hpp"
  81 #include "runtime/flags/jvmFlagLimit.hpp"
  82 #include "runtime/deoptimization.hpp"
  83 #include "runtime/frame.inline.hpp"
  84 #include "runtime/handles.inline.hpp"
  85 #include "runtime/handshake.hpp"
  86 #include "runtime/init.hpp"
  87 #include "runtime/interfaceSupport.inline.hpp"
  88 #include "runtime/java.hpp"
  89 #include "runtime/javaCalls.hpp"
  90 #include "runtime/jniHandles.inline.hpp"
  91 #include "runtime/jniPeriodicChecker.hpp"
  92 #include "runtime/lockStack.inline.hpp"
  93 #include "runtime/monitorDeflationThread.hpp"
  94 #include "runtime/mutexLocker.hpp"
  95 #include "runtime/nonJavaThread.hpp"
  96 #include "runtime/objectMonitor.inline.hpp"
  97 #include "runtime/orderAccess.hpp"
  98 #include "runtime/osThread.hpp"
  99 #include "runtime/prefetch.inline.hpp"
 100 #include "runtime/safepoint.hpp"
 101 #include "runtime/safepointMechanism.inline.hpp"
 102 #include "runtime/safepointVerifiers.hpp"
 103 #include "runtime/serviceThread.hpp"
 104 #include "runtime/sharedRuntime.hpp"
 105 #include "runtime/stackFrameStream.inline.hpp"
 106 #include "runtime/stackWatermarkSet.hpp"
 107 #include "runtime/statSampler.hpp"
 108 #include "runtime/task.hpp"
 109 #include "runtime/thread.inline.hpp"
 110 #include "runtime/threadCritical.hpp"
 111 #include "runtime/threadSMR.inline.hpp"
 112 #include "runtime/threadStatisticalInfo.hpp"
 113 #include "runtime/threadWXSetters.inline.hpp"
 114 #include "runtime/timer.hpp"
 115 #include "runtime/timerTrace.hpp"
 116 #include "runtime/trimNativeHeap.hpp"
 117 #include "runtime/vframe.inline.hpp"
 118 #include "runtime/vframeArray.hpp"
 119 #include "runtime/vframe_hp.hpp"
 120 #include "runtime/vmThread.hpp"
 121 #include "runtime/vmOperations.hpp"
 122 #include "runtime/vm_version.hpp"
 123 #include "services/attachListener.hpp"
 124 #include "services/management.hpp"
 125 #include "services/memTracker.hpp"
 126 #include "services/threadService.hpp"
 127 #include "utilities/align.hpp"
 128 #include "utilities/copy.hpp"
 129 #include "utilities/defaultStream.hpp"
 130 #include "utilities/dtrace.hpp"
 131 #include "utilities/events.hpp"
 132 #include "utilities/macros.hpp"
 133 #include "utilities/preserveException.hpp"
 134 #include "utilities/spinYield.hpp"
 135 #include "utilities/vmError.hpp"
 136 #if INCLUDE_JVMCI
 137 #include "jvmci/jvmci.hpp"
 138 #include "jvmci/jvmciEnv.hpp"
 139 #endif
 140 #ifdef COMPILER1
 141 #include "c1/c1_Compiler.hpp"
 142 #endif
 143 #ifdef COMPILER2
 144 #include "opto/c2compiler.hpp"
 145 #include "opto/idealGraphPrinter.hpp"
 146 #endif
 147 #if INCLUDE_RTM_OPT
 148 #include "runtime/rtmLocking.hpp"
 149 #endif
 150 #if INCLUDE_JFR
 151 #include "jfr/jfr.hpp"
 152 #endif
 153 #if INCLUDE_VM_STRUCTS
 154 #include "runtime/vmStructs.hpp"
 155 #endif
 156 
 157 // Initialization after module runtime initialization
 158 void universe_post_module_init();  // must happen after call_initPhase2
 159 
 160 #ifdef DTRACE_ENABLED
 161 
 162 // Only bother with this argument setup if dtrace is available
 163 
 164   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 165   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 166 
 167   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 168     {                                                                      \
 169       ResourceMark rm(this);                                               \
 170       int len = 0;                                                         \
 171       const char* name = (javathread)->get_thread_name();                  \
 172       len = strlen(name);                                                  \
 173       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 174         (char *) name, len,                                                \
 175         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 176         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 177         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 178     }
 179 
 180 #else //  ndef DTRACE_ENABLED
 181 
 182   #define DTRACE_THREAD_PROBE(probe, javathread)
 183 
 184 #endif // ndef DTRACE_ENABLED
 185 
 186 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 187 // Current thread is maintained as a thread-local variable
 188 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
 189 #endif
 190 
 191 // ======= Thread ========
 192 // Support for forcing alignment of thread objects for biased locking
 193 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 194   if (UseBiasedLocking) {
 195     const size_t alignment = markWord::biased_lock_alignment;
 196     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 197     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 198                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 199                                                          AllocFailStrategy::RETURN_NULL);
 200     void* aligned_addr     = align_up(real_malloc_addr, alignment);
 201     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 202            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 203            "JavaThread alignment code overflowed allocated storage");
 204     if (aligned_addr != real_malloc_addr) {
 205       log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 206                               p2i(real_malloc_addr),
 207                               p2i(aligned_addr));
 208     }
 209     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 210     return aligned_addr;
 211   } else {
 212     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 213                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 214   }
 215 }
 216 
 217 void Thread::operator delete(void* p) {
 218   if (UseBiasedLocking) {
 219     FreeHeap(((Thread*) p)->_real_malloc_address);
 220   } else {
 221     FreeHeap(p);
 222   }
 223 }
 224 
 225 void JavaThread::smr_delete() {
 226   if (_on_thread_list) {
 227     ThreadsSMRSupport::smr_delete(this);
 228   } else {
 229     delete this;
 230   }
 231 }
 232 
 233 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 234 // JavaThread
 235 
 236 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
 237 
 238 Thread::Thread() {
 239 
 240   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 241 
 242   // stack and get_thread
 243   set_stack_base(NULL);
 244   set_stack_size(0);
 245   set_lgrp_id(-1);
 246   DEBUG_ONLY(clear_suspendible_thread();)
 247 
 248   // allocated data structures
 249   set_osthread(NULL);
 250   set_resource_area(new (mtThread)ResourceArea());
 251   DEBUG_ONLY(_current_resource_mark = NULL;)
 252   set_handle_area(new (mtThread) HandleArea(NULL));
 253   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
 254   set_active_handles(NULL);
 255   set_free_handle_block(NULL);
 256   set_last_handle_mark(NULL);
 257   DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
 258 
 259   // Initial value of zero ==> never claimed.
 260   _threads_do_token = 0;
 261   _threads_hazard_ptr = NULL;
 262   _threads_list_ptr = NULL;
 263   _nested_threads_hazard_ptr_cnt = 0;
 264   _rcu_counter = 0;
 265 
 266   // the handle mark links itself to last_handle_mark
 267   new HandleMark(this);
 268 
 269   // plain initialization
 270   debug_only(_owned_locks = NULL;)
 271   NOT_PRODUCT(_skip_gcalot = false;)
 272   _jvmti_env_iteration_count = 0;
 273   set_allocated_bytes(0);
 274   _current_pending_raw_monitor = NULL;
 275 
 276   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 277   _hashStateX = os::random();
 278   _hashStateY = 842502087;
 279   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 280   _hashStateW = 273326509;
 281 
 282   // Many of the following fields are effectively final - immutable
 283   // Note that nascent threads can't use the Native Monitor-Mutex
 284   // construct until the _MutexEvent is initialized ...
 285   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 286   // we might instead use a stack of ParkEvents that we could provision on-demand.
 287   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 288   // and ::Release()
 289   _ParkEvent   = ParkEvent::Allocate(this);
 290 
 291 #ifdef CHECK_UNHANDLED_OOPS
 292   if (CheckUnhandledOops) {
 293     _unhandled_oops = new UnhandledOops(this);
 294   }
 295 #endif // CHECK_UNHANDLED_OOPS
 296 #ifdef ASSERT
 297   if (UseBiasedLocking) {
 298     assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed");
 299     assert(this == _real_malloc_address ||
 300            this == align_up(_real_malloc_address, markWord::biased_lock_alignment),
 301            "bug in forced alignment of thread objects");
 302   }
 303 #endif // ASSERT
 304 
 305   // Notify the barrier set that a thread is being created. The initial
 306   // thread is created before the barrier set is available.  The call to
 307   // BarrierSet::on_thread_create() for this thread is therefore deferred
 308   // to BarrierSet::set_barrier_set().
 309   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 310   if (barrier_set != NULL) {
 311     barrier_set->on_thread_create(this);
 312   } else {
 313     // Only the main thread should be created before the barrier set
 314     // and that happens just before Thread::current is set. No other thread
 315     // can attach as the VM is not created yet, so they can't execute this code.
 316     // If the main thread creates other threads before the barrier set that is an error.
 317     assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
 318   }
 319 
 320   MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
 321 }
 322 
 323 void Thread::initialize_tlab() {
 324   if (UseTLAB) {
 325     tlab().initialize();
 326   }
 327 }
 328 
 329 void Thread::initialize_thread_current() {
 330 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 331   assert(_thr_current == NULL, "Thread::current already initialized");
 332   _thr_current = this;
 333 #endif
 334   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 335   ThreadLocalStorage::set_thread(this);
 336   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 337 }
 338 
 339 void Thread::clear_thread_current() {
 340   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 341 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 342   _thr_current = NULL;
 343 #endif
 344   ThreadLocalStorage::set_thread(NULL);
 345 }
 346 
 347 void Thread::record_stack_base_and_size() {
 348   // Note: at this point, Thread object is not yet initialized. Do not rely on
 349   // any members being initialized. Do not rely on Thread::current() being set.
 350   // If possible, refrain from doing anything which may crash or assert since
 351   // quite probably those crash dumps will be useless.
 352   set_stack_base(os::current_stack_base());
 353   set_stack_size(os::current_stack_size());
 354 
 355   // Set stack limits after thread is initialized.
 356   if (is_Java_thread()) {
 357     as_Java_thread()->stack_overflow_state()->initialize(stack_base(), stack_end());
 358   }
 359 }
 360 
 361 #if INCLUDE_NMT
 362 void Thread::register_thread_stack_with_NMT() {
 363   MemTracker::record_thread_stack(stack_end(), stack_size());
 364 }
 365 
 366 void Thread::unregister_thread_stack_with_NMT() {
 367   MemTracker::release_thread_stack(stack_end(), stack_size());
 368 }
 369 #endif // INCLUDE_NMT
 370 
 371 void Thread::call_run() {
 372   DEBUG_ONLY(_run_state = CALL_RUN;)
 373 
 374   // At this point, Thread object should be fully initialized and
 375   // Thread::current() should be set.
 376 
 377   assert(Thread::current_or_null() != NULL, "current thread is unset");
 378   assert(Thread::current_or_null() == this, "current thread is wrong");
 379 
 380   // Perform common initialization actions
 381 
 382   MACOS_AARCH64_ONLY(this->init_wx());
 383 
 384   register_thread_stack_with_NMT();
 385 
 386   JFR_ONLY(Jfr::on_thread_start(this);)
 387 
 388   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 389     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 390     os::current_thread_id(), p2i(stack_end()),
 391     p2i(stack_base()), stack_size()/1024);
 392 
 393   // Perform <ChildClass> initialization actions
 394   DEBUG_ONLY(_run_state = PRE_RUN;)
 395   this->pre_run();
 396 
 397   // Invoke <ChildClass>::run()
 398   DEBUG_ONLY(_run_state = RUN;)
 399   this->run();
 400   // Returned from <ChildClass>::run(). Thread finished.
 401 
 402   // Perform common tear-down actions
 403 
 404   assert(Thread::current_or_null() != NULL, "current thread is unset");
 405   assert(Thread::current_or_null() == this, "current thread is wrong");
 406 
 407   // Perform <ChildClass> tear-down actions
 408   DEBUG_ONLY(_run_state = POST_RUN;)
 409   this->post_run();
 410 
 411   // Note: at this point the thread object may already have deleted itself,
 412   // so from here on do not dereference *this*. Not all thread types currently
 413   // delete themselves when they terminate. But no thread should ever be deleted
 414   // asynchronously with respect to its termination - that is what _run_state can
 415   // be used to check.
 416 
 417   assert(Thread::current_or_null() == NULL, "current thread still present");
 418 }
 419 
 420 Thread::~Thread() {
 421 
 422   // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
 423   // get started due to errors etc. Any active thread should at least reach post_run
 424   // before it is deleted (usually in post_run()).
 425   assert(_run_state == PRE_CALL_RUN ||
 426          _run_state == POST_RUN, "Active Thread deleted before post_run(): "
 427          "_run_state=%d", (int)_run_state);
 428 
 429   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 430   // set might not be available if we encountered errors during bootstrapping.
 431   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 432   if (barrier_set != NULL) {
 433     barrier_set->on_thread_destroy(this);
 434   }
 435 
 436   // deallocate data structures
 437   delete resource_area();
 438   // since the handle marks are using the handle area, we have to deallocated the root
 439   // handle mark before deallocating the thread's handle area,
 440   assert(last_handle_mark() != NULL, "check we have an element");
 441   delete last_handle_mark();
 442   assert(last_handle_mark() == NULL, "check we have reached the end");
 443 
 444   ParkEvent::Release(_ParkEvent);
 445   // Set to NULL as a termination indicator for has_terminated().
 446   Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
 447 
 448   delete handle_area();
 449   delete metadata_handles();
 450 
 451   // osthread() can be NULL, if creation of thread failed.
 452   if (osthread() != NULL) os::free_thread(osthread());
 453 
 454   // Clear Thread::current if thread is deleting itself and it has not
 455   // already been done. This must be done before the memory is deallocated.
 456   // Needed to ensure JNI correctly detects non-attached threads.
 457   if (this == Thread::current_or_null()) {
 458     Thread::clear_thread_current();
 459   }
 460 
 461   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 462 }
 463 
 464 #ifdef ASSERT
 465 // A JavaThread is considered dangling if it not handshake-safe with respect to
 466 // the current thread, it is not on a ThreadsList, or not at safepoint.
 467 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 468   assert(!thread->is_Java_thread() ||
 469          thread->as_Java_thread()->is_handshake_safe_for(Thread::current()) ||
 470          !thread->as_Java_thread()->on_thread_list() ||
 471          SafepointSynchronize::is_at_safepoint() ||
 472          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(thread->as_Java_thread()),
 473          "possibility of dangling Thread pointer");
 474 }
 475 #endif
 476 
 477 // Is the target JavaThread protected by the calling Thread
 478 // or by some other mechanism:
 479 bool Thread::is_JavaThread_protected(const JavaThread* p) {
 480   // Do the simplest check first:
 481   if (SafepointSynchronize::is_at_safepoint()) {
 482     // The target is protected since JavaThreads cannot exit
 483     // while we're at a safepoint.
 484     return true;
 485   }
 486 
 487   // If the target hasn't been started yet then it is trivially
 488   // "protected". We assume the caller is the thread that will do
 489   // the starting.
 490   if (p->osthread() == NULL || p->osthread()->get_state() <= INITIALIZED) {
 491     return true;
 492   }
 493 
 494   // Now make the simple checks based on who the caller is:
 495   Thread* current_thread = Thread::current();
 496   if (current_thread == p || Threads_lock->owner() == current_thread) {
 497     // Target JavaThread is self or calling thread owns the Threads_lock.
 498     // Second check is the same as Threads_lock->owner_is_self(),
 499     // but we already have the current thread so check directly.
 500     return true;
 501   }
 502 
 503   // Check the ThreadsLists associated with the calling thread (if any)
 504   // to see if one of them protects the target JavaThread:
 505   for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
 506        stlp != NULL; stlp = stlp->previous()) {
 507     if (stlp->list()->includes(p)) {
 508       // The target JavaThread is protected by this ThreadsList:
 509       return true;
 510     }
 511   }
 512 
 513   // Use this debug code with -XX:+UseNewCode to diagnose locations that
 514   // are missing a ThreadsListHandle or other protection mechanism:
 515   // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting p="
 516   //           INTPTR_FORMAT, p2i(current_thread), p2i(p));
 517 
 518   // Note: Since 'p' isn't protected by a TLH, the call to
 519   // p->is_handshake_safe_for() may crash, but we have debug bits so
 520   // we'll be able to figure out what protection mechanism is missing.
 521   assert(p->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
 522          " is not protected and not handshake safe.", p2i(p));
 523 
 524   // The target JavaThread is not protected so it is not safe to query:
 525   return false;
 526 }
 527 
 528 ThreadPriority Thread::get_priority(const Thread* const thread) {
 529   ThreadPriority priority;
 530   // Can return an error!
 531   (void)os::get_priority(thread, priority);
 532   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 533   return priority;
 534 }
 535 
 536 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 537   debug_only(check_for_dangling_thread_pointer(thread);)
 538   // Can return an error!
 539   (void)os::set_priority(thread, priority);
 540 }
 541 
 542 
 543 void Thread::start(Thread* thread) {
 544   // Start is different from resume in that its safety is guaranteed by context or
 545   // being called from a Java method synchronized on the Thread object.
 546   if (thread->is_Java_thread()) {
 547     // Initialize the thread state to RUNNABLE before starting this thread.
 548     // Can not set it after the thread started because we do not know the
 549     // exact thread state at that time. It could be in MONITOR_WAIT or
 550     // in SLEEPING or some other state.
 551     java_lang_Thread::set_thread_status(thread->as_Java_thread()->threadObj(),
 552                                         JavaThreadStatus::RUNNABLE);
 553   }
 554   os::start_thread(thread);
 555 }
 556 
 557 // GC Support
 558 bool Thread::claim_par_threads_do(uintx claim_token) {
 559   uintx token = _threads_do_token;
 560   if (token != claim_token) {
 561     uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
 562     if (res == token) {
 563       return true;
 564     }
 565     guarantee(res == claim_token, "invariant");
 566   }
 567   return false;
 568 }
 569 
 570 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
 571   if (active_handles() != NULL) {
 572     active_handles()->oops_do(f);
 573   }
 574   // Do oop for ThreadShadow
 575   f->do_oop((oop*)&_pending_exception);
 576   handle_area()->oops_do(f);
 577 }
 578 
 579 // If the caller is a NamedThread, then remember, in the current scope,
 580 // the given JavaThread in its _processed_thread field.
 581 class RememberProcessedThread: public StackObj {
 582   NamedThread* _cur_thr;
 583 public:
 584   RememberProcessedThread(Thread* thread) {
 585     Thread* self = Thread::current();
 586     if (self->is_Named_thread()) {
 587       _cur_thr = (NamedThread *)self;
 588       assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
 589       _cur_thr->set_processed_thread(thread);
 590     } else {
 591       _cur_thr = NULL;
 592     }
 593   }
 594 
 595   ~RememberProcessedThread() {
 596     if (_cur_thr) {
 597       assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
 598       _cur_thr->set_processed_thread(NULL);
 599     }
 600   }
 601 };
 602 
 603 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 604   // Record JavaThread to GC thread
 605   RememberProcessedThread rpt(this);
 606   oops_do_no_frames(f, cf);
 607   oops_do_frames(f, cf);
 608 }
 609 
 610 void Thread::metadata_handles_do(void f(Metadata*)) {
 611   // Only walk the Handles in Thread.
 612   if (metadata_handles() != NULL) {
 613     for (int i = 0; i< metadata_handles()->length(); i++) {
 614       f(metadata_handles()->at(i));
 615     }
 616   }
 617 }
 618 
 619 void Thread::print_on(outputStream* st, bool print_extended_info) const {
 620   // get_priority assumes osthread initialized
 621   if (osthread() != NULL) {
 622     int os_prio;
 623     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 624       st->print("os_prio=%d ", os_prio);
 625     }
 626 
 627     st->print("cpu=%.2fms ",
 628               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 629               );
 630     st->print("elapsed=%.2fs ",
 631               _statistical_info.getElapsedTime() / 1000.0
 632               );
 633     if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
 634       size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
 635       st->print("allocated=" SIZE_FORMAT "%s ",
 636                 byte_size_in_proper_unit(allocated_bytes),
 637                 proper_unit_for_byte_size(allocated_bytes)
 638                 );
 639       st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
 640     }
 641 
 642     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 643     osthread()->print_on(st);
 644   }
 645   ThreadsSMRSupport::print_info_on(this, st);
 646   st->print(" ");
 647   debug_only(if (WizardMode) print_owned_locks_on(st);)
 648 }
 649 
 650 void Thread::print() const { print_on(tty); }
 651 
 652 // Thread::print_on_error() is called by fatal error handler. Don't use
 653 // any lock or allocate memory.
 654 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 655   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 656 
 657   if (is_VM_thread())                 { st->print("VMThread"); }
 658   else if (is_GC_task_thread())       { st->print("GCTaskThread"); }
 659   else if (is_Watcher_thread())       { st->print("WatcherThread"); }
 660   else if (is_ConcurrentGC_thread())  { st->print("ConcurrentGCThread"); }
 661   else if (this == AsyncLogWriter::instance()) {
 662     st->print("%s", this->name());
 663   } else                                { st->print("Thread"); }
 664 
 665   if (is_Named_thread()) {
 666     st->print(" \"%s\"", name());
 667   }
 668 
 669   OSThread* os_thr = osthread();
 670   if (os_thr != NULL) {
 671     if (os_thr->get_state() != ZOMBIE) {
 672       st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 673                 p2i(stack_end()), p2i(stack_base()));
 674       st->print(" [id=%d]", osthread()->thread_id());
 675     } else {
 676       st->print(" terminated");
 677     }
 678   } else {
 679     st->print(" unknown state (no osThread)");
 680   }
 681   ThreadsSMRSupport::print_info_on(this, st);
 682 }
 683 
 684 void Thread::print_value_on(outputStream* st) const {
 685   if (is_Named_thread()) {
 686     st->print(" \"%s\" ", name());
 687   }
 688   st->print(INTPTR_FORMAT, p2i(this));   // print address
 689 }
 690 
 691 #ifdef ASSERT
 692 void Thread::print_owned_locks_on(outputStream* st) const {
 693   Mutex* cur = _owned_locks;
 694   if (cur == NULL) {
 695     st->print(" (no locks) ");
 696   } else {
 697     st->print_cr(" Locks owned:");
 698     while (cur) {
 699       cur->print_on(st);
 700       cur = cur->next();
 701     }
 702   }
 703 }
 704 #endif // ASSERT
 705 
 706 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 707 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 708 // used for compilation in the future. If that change is made, the need for these methods
 709 // should be revisited, and they should be removed if possible.
 710 
 711 bool Thread::is_lock_owned(address adr) const {
 712   assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
 713   return is_in_full_stack(adr);
 714 }
 715 
 716 bool Thread::set_as_starting_thread() {
 717   assert(_starting_thread == NULL, "already initialized: "
 718          "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
 719   // NOTE: this must be called inside the main thread.
 720   DEBUG_ONLY(_starting_thread = this;)
 721   return os::create_main_thread(this->as_Java_thread());
 722 }
 723 
 724 static void initialize_class(Symbol* class_name, TRAPS) {
 725   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 726   InstanceKlass::cast(klass)->initialize(CHECK);
 727 }
 728 
 729 
 730 // Creates the initial ThreadGroup
 731 static Handle create_initial_thread_group(TRAPS) {
 732   Handle system_instance = JavaCalls::construct_new_instance(
 733                             vmClasses::ThreadGroup_klass(),
 734                             vmSymbols::void_method_signature(),
 735                             CHECK_NH);
 736   Universe::set_system_thread_group(system_instance());
 737 
 738   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 739   Handle main_instance = JavaCalls::construct_new_instance(
 740                             vmClasses::ThreadGroup_klass(),
 741                             vmSymbols::threadgroup_string_void_signature(),
 742                             system_instance,
 743                             string,
 744                             CHECK_NH);
 745   return main_instance;
 746 }
 747 
 748 // Creates the initial Thread, and sets it to running.
 749 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 750                                  TRAPS) {
 751   InstanceKlass* ik = vmClasses::Thread_klass();
 752   assert(ik->is_initialized(), "must be");
 753   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 754 
 755   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 756   // constructor calls Thread.current(), which must be set here for the
 757   // initial thread.
 758   java_lang_Thread::set_thread(thread_oop(), thread);
 759   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 760   thread->set_threadObj(thread_oop());
 761 
 762   Handle string = java_lang_String::create_from_str("main", CHECK);
 763 
 764   JavaValue result(T_VOID);
 765   JavaCalls::call_special(&result, thread_oop,
 766                           ik,
 767                           vmSymbols::object_initializer_name(),
 768                           vmSymbols::threadgroup_string_void_signature(),
 769                           thread_group,
 770                           string,
 771                           CHECK);
 772 
 773   // Set thread status to running since main thread has
 774   // been started and running.
 775   java_lang_Thread::set_thread_status(thread_oop(),
 776                                       JavaThreadStatus::RUNNABLE);
 777 }
 778 
 779 // Extract version and vendor specific information from
 780 // java.lang.VersionProps fields.
 781 // Returned char* is allocated in the thread's resource area
 782 // so must be copied for permanency.
 783 static const char* get_java_version_info(InstanceKlass* ik,
 784                                          Symbol* field_name) {
 785   fieldDescriptor fd;
 786   bool found = ik != NULL &&
 787                ik->find_local_field(field_name,
 788                                     vmSymbols::string_signature(), &fd);
 789   if (found) {
 790     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 791     if (name_oop == NULL) {
 792       return NULL;
 793     }
 794     const char* name = java_lang_String::as_utf8_string(name_oop);
 795     return name;
 796   } else {
 797     return NULL;
 798   }
 799 }
 800 
 801 // General purpose hook into Java code, run once when the VM is initialized.
 802 // The Java library method itself may be changed independently from the VM.
 803 static void call_postVMInitHook(TRAPS) {
 804   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 805   if (klass != NULL) {
 806     JavaValue result(T_VOID);
 807     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 808                            vmSymbols::void_method_signature(),
 809                            CHECK);
 810   }
 811 }
 812 
 813 // Initialized by VMThread at vm_global_init
 814 static OopStorage* _thread_oop_storage = NULL;
 815 
 816 oop  JavaThread::threadObj() const    {
 817   return _threadObj.resolve();
 818 }
 819 
 820 void JavaThread::set_threadObj(oop p) {
 821   assert(_thread_oop_storage != NULL, "not yet initialized");
 822   _threadObj = OopHandle(_thread_oop_storage, p);
 823 }
 824 
 825 OopStorage* JavaThread::thread_oop_storage() {
 826   assert(_thread_oop_storage != NULL, "not yet initialized");
 827   return _thread_oop_storage;
 828 }
 829 
 830 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 831                                     bool daemon, TRAPS) {
 832   assert(thread_group.not_null(), "thread group should be specified");
 833   assert(threadObj() == NULL, "should only create Java thread object once");
 834 
 835   InstanceKlass* ik = vmClasses::Thread_klass();
 836   assert(ik->is_initialized(), "must be");
 837   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 838 
 839   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 840   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 841   // constructor calls Thread.current(), which must be set here.
 842   java_lang_Thread::set_thread(thread_oop(), this);
 843   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 844   set_threadObj(thread_oop());
 845 
 846   JavaValue result(T_VOID);
 847   if (thread_name != NULL) {
 848     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 849     // Thread gets assigned specified name and null target
 850     JavaCalls::call_special(&result,
 851                             thread_oop,
 852                             ik,
 853                             vmSymbols::object_initializer_name(),
 854                             vmSymbols::threadgroup_string_void_signature(),
 855                             thread_group,
 856                             name,
 857                             THREAD);
 858   } else {
 859     // Thread gets assigned name "Thread-nnn" and null target
 860     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 861     JavaCalls::call_special(&result,
 862                             thread_oop,
 863                             ik,
 864                             vmSymbols::object_initializer_name(),
 865                             vmSymbols::threadgroup_runnable_void_signature(),
 866                             thread_group,
 867                             Handle(),
 868                             THREAD);
 869   }
 870 
 871 
 872   if (daemon) {
 873     java_lang_Thread::set_daemon(thread_oop());
 874   }
 875 
 876   if (HAS_PENDING_EXCEPTION) {
 877     return;
 878   }
 879 
 880   Klass* group = vmClasses::ThreadGroup_klass();
 881   Handle threadObj(THREAD, this->threadObj());
 882 
 883   JavaCalls::call_special(&result,
 884                           thread_group,
 885                           group,
 886                           vmSymbols::add_method_name(),
 887                           vmSymbols::thread_void_signature(),
 888                           threadObj,          // Arg 1
 889                           THREAD);
 890 }
 891 
 892 // ======= JavaThread ========
 893 
 894 #if INCLUDE_JVMCI
 895 
 896 jlong* JavaThread::_jvmci_old_thread_counters;
 897 
 898 bool jvmci_counters_include(JavaThread* thread) {
 899   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 900 }
 901 
 902 void JavaThread::collect_counters(jlong* array, int length) {
 903   assert(length == JVMCICounterSize, "wrong value");
 904   for (int i = 0; i < length; i++) {
 905     array[i] = _jvmci_old_thread_counters[i];
 906   }
 907   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
 908     if (jvmci_counters_include(tp)) {
 909       for (int i = 0; i < length; i++) {
 910         array[i] += tp->_jvmci_counters[i];
 911       }
 912     }
 913   }
 914 }
 915 
 916 // Attempt to enlarge the array for per thread counters.
 917 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 918   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 919   if (new_counters == NULL) {
 920     return NULL;
 921   }
 922   if (old_counters == NULL) {
 923     old_counters = new_counters;
 924     memset(old_counters, 0, sizeof(jlong) * new_size);
 925   } else {
 926     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 927       new_counters[i] = old_counters[i];
 928     }
 929     if (new_size > current_size) {
 930       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 931     }
 932     FREE_C_HEAP_ARRAY(jlong, old_counters);
 933   }
 934   return new_counters;
 935 }
 936 
 937 // Attempt to enlarge the array for per thread counters.
 938 bool JavaThread::resize_counters(int current_size, int new_size) {
 939   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 940   if (new_counters == NULL) {
 941     return false;
 942   } else {
 943     _jvmci_counters = new_counters;
 944     return true;
 945   }
 946 }
 947 
 948 class VM_JVMCIResizeCounters : public VM_Operation {
 949  private:
 950   int _new_size;
 951   bool _failed;
 952 
 953  public:
 954   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 955   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 956   bool allow_nested_vm_operations() const        { return true; }
 957   void doit() {
 958     // Resize the old thread counters array
 959     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 960     if (new_counters == NULL) {
 961       _failed = true;
 962       return;
 963     } else {
 964       JavaThread::_jvmci_old_thread_counters = new_counters;
 965     }
 966 
 967     // Now resize each threads array
 968     for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) {
 969       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 970         _failed = true;
 971         break;
 972       }
 973     }
 974     if (!_failed) {
 975       JVMCICounterSize = _new_size;
 976     }
 977   }
 978 
 979   bool failed() { return _failed; }
 980 };
 981 
 982 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 983   VM_JVMCIResizeCounters op(new_size);
 984   VMThread::execute(&op);
 985   return !op.failed();
 986 }
 987 
 988 #endif // INCLUDE_JVMCI
 989 
 990 #ifdef ASSERT
 991 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 992 void JavaThread::check_possible_safepoint() {
 993   if (_no_safepoint_count > 0) {
 994     print_owned_locks();
 995     assert(false, "Possible safepoint reached by thread that does not allow it");
 996   }
 997 #ifdef CHECK_UNHANDLED_OOPS
 998   // Clear unhandled oops in JavaThreads so we get a crash right away.
 999   clear_unhandled_oops();
1000 #endif // CHECK_UNHANDLED_OOPS
1001 }
1002 
1003 void JavaThread::check_for_valid_safepoint_state() {
1004   // Check NoSafepointVerifier, which is implied by locks taken that can be
1005   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
1006   // are held.
1007   check_possible_safepoint();
1008 
1009   if (thread_state() != _thread_in_vm) {
1010     fatal("LEAF method calling lock?");
1011   }
1012 
1013   if (GCALotAtAllSafepoints) {
1014     // We could enter a safepoint here and thus have a gc
1015     InterfaceSupport::check_gc_alot();
1016   }
1017 }
1018 #endif // ASSERT
1019 
1020 // A JavaThread is a normal Java thread
1021 
1022 JavaThread::JavaThread() :
1023   // Initialize fields
1024 
1025   _in_asgct(false),
1026   _on_thread_list(false),
1027   DEBUG_ONLY(_java_call_counter(0) COMMA)
1028   _entry_point(nullptr),
1029   _deopt_mark(nullptr),
1030   _deopt_nmethod(nullptr),
1031   _vframe_array_head(nullptr),
1032   _vframe_array_last(nullptr),
1033   _jvmti_deferred_updates(nullptr),
1034   _callee_target(nullptr),
1035   _vm_result(nullptr),
1036   _vm_result_2(nullptr),
1037 
1038   _current_pending_monitor(NULL),
1039   _current_pending_monitor_is_from_java(true),
1040   _current_waiting_monitor(NULL),
1041   _Stalled(0),
1042 
1043   _monitor_chunks(nullptr),
1044 
1045   _suspend_flags(0),
1046   _async_exception_condition(_no_async_condition),
1047   _pending_async_exception(nullptr),
1048 
1049   _thread_state(_thread_new),
1050   _saved_exception_pc(nullptr),
1051 #ifdef ASSERT
1052   _no_safepoint_count(0),
1053   _visited_for_critical_count(false),
1054 #endif
1055 
1056   _terminated(_not_terminated),
1057   _in_deopt_handler(0),
1058   _doing_unsafe_access(false),
1059   _do_not_unlock_if_synchronized(false),
1060   _jni_attach_state(_not_attaching_via_jni),
1061 #if INCLUDE_JVMCI
1062   _pending_deoptimization(-1),
1063   _pending_monitorenter(false),
1064   _pending_transfer_to_interpreter(false),
1065   _in_retryable_allocation(false),
1066   _pending_failed_speculation(0),
1067   _jvmci{nullptr},
1068   _jvmci_counters(nullptr),
1069   _jvmci_reserved0(0),
1070   _jvmci_reserved1(0),
1071   _jvmci_reserved_oop0(nullptr),
1072 #endif // INCLUDE_JVMCI
1073 
1074   _exception_oop(oop()),
1075   _exception_pc(0),
1076   _exception_handler_pc(0),
1077   _is_method_handle_return(0),
1078 
1079   _jni_active_critical(0),
1080   _pending_jni_exception_check_fn(nullptr),
1081   _depth_first_number(0),
1082 
1083   // JVMTI PopFrame support
1084   _popframe_condition(popframe_inactive),
1085   _frames_to_pop_failed_realloc(0),
1086 
1087   _handshake(this),
1088 
1089   _popframe_preserved_args(nullptr),
1090   _popframe_preserved_args_size(0),
1091 
1092   _jvmti_thread_state(nullptr),
1093   _interp_only_mode(0),
1094   _should_post_on_exceptions_flag(JNI_FALSE),
1095   _thread_stat(new ThreadStatistics()),
1096 
1097   _parker(),
1098   _cached_monitor_info(nullptr),
1099 
1100   _class_to_be_initialized(nullptr),
1101 
1102   _SleepEvent(ParkEvent::Allocate(this)),
1103 
1104   _lock_stack(this) {
1105   set_jni_functions(jni_functions());
1106 
1107 #if INCLUDE_JVMCI
1108   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
1109   if (JVMCICounterSize > 0) {
1110     resize_counters(0, (int) JVMCICounterSize);
1111   }
1112 #endif // INCLUDE_JVMCI
1113 
1114   // Setup safepoint state info for this thread
1115   ThreadSafepointState::create(this);
1116 
1117   SafepointMechanism::initialize_header(this);
1118 
1119   set_requires_cross_modify_fence(false);
1120 
1121   pd_initialize();
1122   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1123 }
1124 
1125 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
1126   if (is_attaching_via_jni) {
1127     _jni_attach_state = _attaching_via_jni;
1128   }
1129 }
1130 
1131 
1132 // interrupt support
1133 
1134 void JavaThread::interrupt() {
1135   // All callers should have 'this' thread protected by a
1136   // ThreadsListHandle so that it cannot terminate and deallocate
1137   // itself.
1138   debug_only(check_for_dangling_thread_pointer(this);)
1139 
1140   // For Windows _interrupt_event
1141   osthread()->set_interrupted(true);
1142 
1143   // For Thread.sleep
1144   _SleepEvent->unpark();
1145 
1146   // For JSR166 LockSupport.park
1147   parker()->unpark();
1148 
1149   // For ObjectMonitor and JvmtiRawMonitor
1150   _ParkEvent->unpark();
1151 }
1152 
1153 
1154 bool JavaThread::is_interrupted(bool clear_interrupted) {
1155   debug_only(check_for_dangling_thread_pointer(this);)
1156 
1157   if (_threadObj.peek() == NULL) {
1158     // If there is no j.l.Thread then it is impossible to have
1159     // been interrupted. We can find NULL during VM initialization
1160     // or when a JNI thread is still in the process of attaching.
1161     // In such cases this must be the current thread.
1162     assert(this == Thread::current(), "invariant");
1163     return false;
1164   }
1165 
1166   bool interrupted = java_lang_Thread::interrupted(threadObj());
1167 
1168   // NOTE that since there is no "lock" around the interrupt and
1169   // is_interrupted operations, there is the possibility that the
1170   // interrupted flag will be "false" but that the
1171   // low-level events will be in the signaled state. This is
1172   // intentional. The effect of this is that Object.wait() and
1173   // LockSupport.park() will appear to have a spurious wakeup, which
1174   // is allowed and not harmful, and the possibility is so rare that
1175   // it is not worth the added complexity to add yet another lock.
1176   // For the sleep event an explicit reset is performed on entry
1177   // to JavaThread::sleep, so there is no early return. It has also been
1178   // recommended not to put the interrupted flag into the "event"
1179   // structure because it hides the issue.
1180   // Also, because there is no lock, we must only clear the interrupt
1181   // state if we are going to report that we were interrupted; otherwise
1182   // an interrupt that happens just after we read the field would be lost.
1183   if (interrupted && clear_interrupted) {
1184     assert(this == Thread::current(), "only the current thread can clear");
1185     java_lang_Thread::set_interrupted(threadObj(), false);
1186     osthread()->set_interrupted(false);
1187   }
1188 
1189   return interrupted;
1190 }
1191 
1192 void JavaThread::block_if_vm_exited() {
1193   if (_terminated == _vm_exited) {
1194     // _vm_exited is set at safepoint, and Threads_lock is never released
1195     // we will block here forever.
1196     // Here we can be doing a jump from a safe state to an unsafe state without
1197     // proper transition, but it happens after the final safepoint has begun.
1198     set_thread_state(_thread_in_vm);
1199     Threads_lock->lock();
1200     ShouldNotReachHere();
1201   }
1202 }
1203 
1204 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
1205   _jni_attach_state = _not_attaching_via_jni;
1206   set_entry_point(entry_point);
1207   // Create the native thread itself.
1208   // %note runtime_23
1209   os::ThreadType thr_type = os::java_thread;
1210   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
1211                                                             os::java_thread;
1212   os::create_thread(this, thr_type, stack_sz);
1213   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1214   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1215   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1216   // the exception consists of creating the exception object & initializing it, initialization
1217   // will leave the VM via a JavaCall and then all locks must be unlocked).
1218   //
1219   // The thread is still suspended when we reach here. Thread must be explicit started
1220   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1221   // by calling Threads:add. The reason why this is not done here, is because the thread
1222   // object must be fully initialized (take a look at JVM_Start)
1223 }
1224 
1225 JavaThread::~JavaThread() {
1226 
1227   // Ask ServiceThread to release the threadObj OopHandle
1228   ServiceThread::add_oop_handle_release(_threadObj);
1229 
1230   // Return the sleep event to the free list
1231   ParkEvent::Release(_SleepEvent);
1232   _SleepEvent = NULL;
1233 
1234   // Free any remaining  previous UnrollBlock
1235   vframeArray* old_array = vframe_array_last();
1236 
1237   if (old_array != NULL) {
1238     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1239     old_array->set_unroll_block(NULL);
1240     delete old_info;
1241     delete old_array;
1242   }
1243 
1244   JvmtiDeferredUpdates* updates = deferred_updates();
1245   if (updates != NULL) {
1246     // This can only happen if thread is destroyed before deoptimization occurs.
1247     assert(updates->count() > 0, "Updates holder not deleted");
1248     // free deferred updates.
1249     delete updates;
1250     set_deferred_updates(NULL);
1251   }
1252 
1253   // All Java related clean up happens in exit
1254   ThreadSafepointState::destroy(this);
1255   if (_thread_stat != NULL) delete _thread_stat;
1256 
1257 #if INCLUDE_JVMCI
1258   if (JVMCICounterSize > 0) {
1259     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1260   }
1261 #endif // INCLUDE_JVMCI
1262 }
1263 
1264 
1265 // First JavaThread specific code executed by a new Java thread.
1266 void JavaThread::pre_run() {
1267   // empty - see comments in run()
1268 }
1269 
1270 // The main routine called by a new Java thread. This isn't overridden
1271 // by subclasses, instead different subclasses define a different "entry_point"
1272 // which defines the actual logic for that kind of thread.
1273 void JavaThread::run() {
1274   // initialize thread-local alloc buffer related fields
1275   initialize_tlab();
1276 
1277   _stack_overflow_state.create_stack_guard_pages();
1278 
1279   cache_global_variables();
1280 
1281   // Thread is now sufficiently initialized to be handled by the safepoint code as being
1282   // in the VM. Change thread state from _thread_new to _thread_in_vm
1283   ThreadStateTransition::transition(this, _thread_new, _thread_in_vm);
1284   // Before a thread is on the threads list it is always safe, so after leaving the
1285   // _thread_new we should emit a instruction barrier. The distance to modified code
1286   // from here is probably far enough, but this is consistent and safe.
1287   OrderAccess::cross_modify_fence();
1288 
1289   assert(JavaThread::current() == this, "sanity check");
1290   assert(!Thread::current()->owns_locks(), "sanity check");
1291 
1292   DTRACE_THREAD_PROBE(start, this);
1293 
1294   // This operation might block. We call that after all safepoint checks for a new thread has
1295   // been completed.
1296   set_active_handles(JNIHandleBlock::allocate_block());
1297 
1298   if (JvmtiExport::should_post_thread_life()) {
1299     JvmtiExport::post_thread_start(this);
1300 
1301   }
1302 
1303   // We call another function to do the rest so we are sure that the stack addresses used
1304   // from there will be lower than the stack base just computed.
1305   thread_main_inner();
1306 }
1307 
1308 void JavaThread::thread_main_inner() {
1309   assert(JavaThread::current() == this, "sanity check");
1310   assert(_threadObj.peek() != NULL, "just checking");
1311 
1312   // Execute thread entry point unless this thread has a pending exception
1313   // or has been stopped before starting.
1314   // Note: Due to JVM_StopThread we can have pending exceptions already!
1315   if (!this->has_pending_exception() &&
1316       !java_lang_Thread::is_stillborn(this->threadObj())) {
1317     {
1318       ResourceMark rm(this);
1319       this->set_native_thread_name(this->get_thread_name());
1320     }
1321     HandleMark hm(this);
1322     this->entry_point()(this, this);
1323   }
1324 
1325   DTRACE_THREAD_PROBE(stop, this);
1326 
1327   // Cleanup is handled in post_run()
1328 }
1329 
1330 // Shared teardown for all JavaThreads
1331 void JavaThread::post_run() {
1332   this->exit(false);
1333   this->unregister_thread_stack_with_NMT();
1334   // Defer deletion to here to ensure 'this' is still referenceable in call_run
1335   // for any shared tear-down.
1336   this->smr_delete();
1337 }
1338 
1339 static void ensure_join(JavaThread* thread) {
1340   // We do not need to grab the Threads_lock, since we are operating on ourself.
1341   Handle threadObj(thread, thread->threadObj());
1342   assert(threadObj.not_null(), "java thread object must exist");
1343   ObjectLocker lock(threadObj, thread);
1344   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1345   thread->clear_pending_exception();
1346   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1347   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
1348   // Clear the native thread instance - this makes isAlive return false and allows the join()
1349   // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
1350   // requirements.
1351   java_lang_Thread::release_set_thread(threadObj(), NULL);
1352   lock.notify_all(thread);
1353   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1354   thread->clear_pending_exception();
1355 }
1356 
1357 static bool is_daemon(oop threadObj) {
1358   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1359 }
1360 
1361 // For any new cleanup additions, please check to see if they need to be applied to
1362 // cleanup_failed_attach_current_thread as well.
1363 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1364   assert(this == JavaThread::current(), "thread consistency check");
1365 
1366   elapsedTimer _timer_exit_phase1;
1367   elapsedTimer _timer_exit_phase2;
1368   elapsedTimer _timer_exit_phase3;
1369   elapsedTimer _timer_exit_phase4;
1370 
1371   if (log_is_enabled(Debug, os, thread, timer)) {
1372     _timer_exit_phase1.start();
1373   }
1374 
1375   HandleMark hm(this);
1376   Handle uncaught_exception(this, this->pending_exception());
1377   this->clear_pending_exception();
1378   Handle threadObj(this, this->threadObj());
1379   assert(threadObj.not_null(), "Java thread object should be created");
1380 
1381   if (!destroy_vm) {
1382     if (uncaught_exception.not_null()) {
1383       EXCEPTION_MARK;
1384       // Call method Thread.dispatchUncaughtException().
1385       Klass* thread_klass = vmClasses::Thread_klass();
1386       JavaValue result(T_VOID);
1387       JavaCalls::call_virtual(&result,
1388                               threadObj, thread_klass,
1389                               vmSymbols::dispatchUncaughtException_name(),
1390                               vmSymbols::throwable_void_signature(),
1391                               uncaught_exception,
1392                               THREAD);
1393       if (HAS_PENDING_EXCEPTION) {
1394         ResourceMark rm(this);
1395         jio_fprintf(defaultStream::error_stream(),
1396                     "\nException: %s thrown from the UncaughtExceptionHandler"
1397                     " in thread \"%s\"\n",
1398                     pending_exception()->klass()->external_name(),
1399                     get_thread_name());
1400         CLEAR_PENDING_EXCEPTION;
1401       }
1402     }
1403 
1404     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1405     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1406     // is deprecated anyhow.
1407     if (!is_Compiler_thread()) {
1408       int count = 3;
1409       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1410         EXCEPTION_MARK;
1411         JavaValue result(T_VOID);
1412         Klass* thread_klass = vmClasses::Thread_klass();
1413         JavaCalls::call_virtual(&result,
1414                                 threadObj, thread_klass,
1415                                 vmSymbols::exit_method_name(),
1416                                 vmSymbols::void_method_signature(),
1417                                 THREAD);
1418         CLEAR_PENDING_EXCEPTION;
1419       }
1420     }
1421     // notify JVMTI
1422     if (JvmtiExport::should_post_thread_life()) {
1423       JvmtiExport::post_thread_end(this);
1424     }
1425 
1426     // The careful dance between thread suspension and exit is handled here.
1427     // Since we are in thread_in_vm state and suspension is done with handshakes,
1428     // we can just put in the exiting state and it will be correctly handled.
1429     set_terminated(_thread_exiting);
1430 
1431     ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1432   } else {
1433     assert(!is_terminated() && !is_exiting(), "must not be exiting");
1434     // before_exit() has already posted JVMTI THREAD_END events
1435   }
1436 
1437   if (log_is_enabled(Debug, os, thread, timer)) {
1438     _timer_exit_phase1.stop();
1439     _timer_exit_phase2.start();
1440   }
1441 
1442   // Capture daemon status before the thread is marked as terminated.
1443   bool daemon = is_daemon(threadObj());
1444 
1445   // Notify waiters on thread object. This has to be done after exit() is called
1446   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1447   // group should have the destroyed bit set before waiters are notified).
1448   ensure_join(this);
1449   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1450 
1451   if (log_is_enabled(Debug, os, thread, timer)) {
1452     _timer_exit_phase2.stop();
1453     _timer_exit_phase3.start();
1454   }
1455   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1456   // held by this thread must be released. The spec does not distinguish
1457   // between JNI-acquired and regular Java monitors. We can only see
1458   // regular Java monitors here if monitor enter-exit matching is broken.
1459   //
1460   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1461   // ObjectSynchronizer::release_monitors_owned_by_thread().
1462   if (exit_type == jni_detach) {
1463     // Sanity check even though JNI DetachCurrentThread() would have
1464     // returned JNI_ERR if there was a Java frame. JavaThread exit
1465     // should be done executing Java code by the time we get here.
1466     assert(!this->has_last_Java_frame(),
1467            "should not have a Java frame when detaching or exiting");
1468     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1469     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1470   }
1471 
1472   // These things needs to be done while we are still a Java Thread. Make sure that thread
1473   // is in a consistent state, in case GC happens
1474   JFR_ONLY(Jfr::on_thread_exit(this);)
1475 
1476   if (active_handles() != NULL) {
1477     JNIHandleBlock* block = active_handles();
1478     set_active_handles(NULL);
1479     JNIHandleBlock::release_block(block);
1480   }
1481 
1482   if (free_handle_block() != NULL) {
1483     JNIHandleBlock* block = free_handle_block();
1484     set_free_handle_block(NULL);
1485     JNIHandleBlock::release_block(block);
1486   }
1487 
1488   // These have to be removed while this is still a valid thread.
1489   _stack_overflow_state.remove_stack_guard_pages();
1490 
1491   if (UseTLAB) {
1492     tlab().retire();
1493   }
1494 
1495   if (JvmtiEnv::environments_might_exist()) {
1496     JvmtiExport::cleanup_thread(this);
1497   }
1498 
1499   // We need to cache the thread name for logging purposes below as once
1500   // we have called on_thread_detach this thread must not access any oops.
1501   char* thread_name = NULL;
1502   if (log_is_enabled(Debug, os, thread, timer)) {
1503     ResourceMark rm(this);
1504     thread_name = os::strdup(get_thread_name());
1505   }
1506 
1507   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1508     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1509     os::current_thread_id());
1510 
1511   if (log_is_enabled(Debug, os, thread, timer)) {
1512     _timer_exit_phase3.stop();
1513     _timer_exit_phase4.start();
1514   }
1515 
1516 #if INCLUDE_JVMCI
1517   if (JVMCICounterSize > 0) {
1518     if (jvmci_counters_include(this)) {
1519       for (int i = 0; i < JVMCICounterSize; i++) {
1520         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1521       }
1522     }
1523   }
1524 #endif // INCLUDE_JVMCI
1525 
1526   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1527   Threads::remove(this, daemon);
1528 
1529   if (log_is_enabled(Debug, os, thread, timer)) {
1530     _timer_exit_phase4.stop();
1531     log_debug(os, thread, timer)("name='%s'"
1532                                  ", exit-phase1=" JLONG_FORMAT
1533                                  ", exit-phase2=" JLONG_FORMAT
1534                                  ", exit-phase3=" JLONG_FORMAT
1535                                  ", exit-phase4=" JLONG_FORMAT,
1536                                  thread_name,
1537                                  _timer_exit_phase1.milliseconds(),
1538                                  _timer_exit_phase2.milliseconds(),
1539                                  _timer_exit_phase3.milliseconds(),
1540                                  _timer_exit_phase4.milliseconds());
1541     os::free(thread_name);
1542   }
1543 }
1544 
1545 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1546   if (active_handles() != NULL) {
1547     JNIHandleBlock* block = active_handles();
1548     set_active_handles(NULL);
1549     JNIHandleBlock::release_block(block);
1550   }
1551 
1552   if (free_handle_block() != NULL) {
1553     JNIHandleBlock* block = free_handle_block();
1554     set_free_handle_block(NULL);
1555     JNIHandleBlock::release_block(block);
1556   }
1557 
1558   // These have to be removed while this is still a valid thread.
1559   _stack_overflow_state.remove_stack_guard_pages();
1560 
1561   if (UseTLAB) {
1562     tlab().retire();
1563   }
1564 
1565   Threads::remove(this, is_daemon);
1566   this->smr_delete();
1567 }
1568 
1569 JavaThread* JavaThread::active() {
1570   Thread* thread = Thread::current();
1571   if (thread->is_Java_thread()) {
1572     return thread->as_Java_thread();
1573   } else {
1574     assert(thread->is_VM_thread(), "this must be a vm thread");
1575     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1576     JavaThread *ret = op == NULL ? NULL : op->calling_thread()->as_Java_thread();
1577     return ret;
1578   }
1579 }
1580 
1581 bool JavaThread::is_lock_owned(address adr) const {
1582   assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1583  if (Thread::is_lock_owned(adr)) return true;
1584 
1585   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1586     if (chunk->contains(adr)) return true;
1587   }
1588 
1589   return false;
1590 }
1591 
1592 oop JavaThread::exception_oop() const {
1593   return Atomic::load(&_exception_oop);
1594 }
1595 
1596 void JavaThread::set_exception_oop(oop o) {
1597   Atomic::store(&_exception_oop, o);
1598 }
1599 
1600 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1601   chunk->set_next(monitor_chunks());
1602   set_monitor_chunks(chunk);
1603 }
1604 
1605 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1606   guarantee(monitor_chunks() != NULL, "must be non empty");
1607   if (monitor_chunks() == chunk) {
1608     set_monitor_chunks(chunk->next());
1609   } else {
1610     MonitorChunk* prev = monitor_chunks();
1611     while (prev->next() != chunk) prev = prev->next();
1612     prev->set_next(chunk->next());
1613   }
1614 }
1615 
1616 
1617 // Asynchronous exceptions support
1618 //
1619 // Note: this function shouldn't block if it's called in
1620 // _thread_in_native_trans state (such as from
1621 // check_special_condition_for_native_trans()).
1622 void JavaThread::check_and_handle_async_exceptions() {
1623   if (has_last_Java_frame() && has_async_exception_condition()) {
1624     // If we are at a polling page safepoint (not a poll return)
1625     // then we must defer async exception because live registers
1626     // will be clobbered by the exception path. Poll return is
1627     // ok because the call we a returning from already collides
1628     // with exception handling registers and so there is no issue.
1629     // (The exception handling path kills call result registers but
1630     //  this is ok since the exception kills the result anyway).
1631 
1632     if (is_at_poll_safepoint()) {
1633       // if the code we are returning to has deoptimized we must defer
1634       // the exception otherwise live registers get clobbered on the
1635       // exception path before deoptimization is able to retrieve them.
1636       //
1637       RegisterMap map(this, false);
1638       frame caller_fr = last_frame().sender(&map);
1639       assert(caller_fr.is_compiled_frame(), "what?");
1640       if (caller_fr.is_deoptimized_frame()) {
1641         log_info(exceptions)("deferred async exception at compiled safepoint");
1642         return;
1643       }
1644     }
1645   }
1646 
1647   AsyncExceptionCondition condition = clear_async_exception_condition();
1648   if (condition == _no_async_condition) {
1649     // Conditions have changed since has_special_runtime_exit_condition()
1650     // was called:
1651     // - if we were here only because of an external suspend request,
1652     //   then that was taken care of above (or cancelled) so we are done
1653     // - if we were here because of another async request, then it has
1654     //   been cleared between the has_special_runtime_exit_condition()
1655     //   and now so again we are done
1656     return;
1657   }
1658 
1659   // Check for pending async. exception
1660   if (_pending_async_exception != NULL) {
1661     // Only overwrite an already pending exception, if it is not a threadDeath.
1662     if (!has_pending_exception() || !pending_exception()->is_a(vmClasses::ThreadDeath_klass())) {
1663 
1664       // We cannot call Exceptions::_throw(...) here because we cannot block
1665       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1666 
1667       LogTarget(Info, exceptions) lt;
1668       if (lt.is_enabled()) {
1669         ResourceMark rm;
1670         LogStream ls(lt);
1671         ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1672           if (has_last_Java_frame()) {
1673             frame f = last_frame();
1674            ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1675           }
1676         ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
1677       }
1678       _pending_async_exception = NULL;
1679       // Clear condition from _suspend_flags since we have finished processing it.
1680       clear_suspend_flag(_has_async_exception);
1681     }
1682   }
1683 
1684   if (condition == _async_unsafe_access_error && !has_pending_exception()) {
1685     // We may be at method entry which requires we save the do-not-unlock flag.
1686     UnlockFlagSaver fs(this);
1687     switch (thread_state()) {
1688     case _thread_in_vm: {
1689       JavaThread* THREAD = this;
1690       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation");
1691       return;
1692     }
1693     case _thread_in_native: {
1694       ThreadInVMfromNative tiv(this);
1695       JavaThread* THREAD = this;
1696       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation");
1697       return;
1698     }
1699     case _thread_in_Java: {
1700       ThreadInVMfromJava tiv(this);
1701       JavaThread* THREAD = this;
1702       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1703       return;
1704     }
1705     default:
1706       ShouldNotReachHere();
1707     }
1708   }
1709 
1710   assert(has_pending_exception(), "must have handled the async condition if no exception");
1711 }
1712 
1713 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1714 
1715   if (is_obj_deopt_suspend()) {
1716     frame_anchor()->make_walkable();
1717     wait_for_object_deoptimization();
1718   }
1719 
1720   // We might be here for reasons in addition to the self-suspend request
1721   // so check for other async requests.
1722   if (check_asyncs) {
1723     check_and_handle_async_exceptions();
1724   }
1725 
1726   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1727 }
1728 
1729 class InstallAsyncExceptionClosure : public HandshakeClosure {
1730   Handle _throwable; // The Throwable thrown at the target Thread
1731 public:
1732   InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
1733 
1734   void do_thread(Thread* thr) {
1735     JavaThread* target = thr->as_Java_thread();
1736     // Note that this now allows multiple ThreadDeath exceptions to be
1737     // thrown at a thread.
1738     // The target thread has run and has not exited yet.
1739     target->send_thread_stop(_throwable());
1740   }
1741 };
1742 
1743 void JavaThread::send_async_exception(oop java_thread, oop java_throwable) {
1744   Handle throwable(Thread::current(), java_throwable);
1745   JavaThread* target = java_lang_Thread::thread(java_thread);
1746   InstallAsyncExceptionClosure vm_stop(throwable);
1747   Handshake::execute(&vm_stop, target);
1748 }
1749 
1750 void JavaThread::send_thread_stop(oop java_throwable)  {
1751   ResourceMark rm;
1752   assert(is_handshake_safe_for(Thread::current()),
1753          "should be self or handshakee");
1754 
1755   // Do not throw asynchronous exceptions against the compiler thread
1756   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1757   if (!can_call_java()) return;
1758 
1759   {
1760     // Actually throw the Throwable against the target Thread - however
1761     // only if there is no thread death exception installed already.
1762     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(vmClasses::ThreadDeath_klass())) {
1763       // If the topmost frame is a runtime stub, then we are calling into
1764       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1765       // must deoptimize the caller before continuing, as the compiled  exception handler table
1766       // may not be valid
1767       if (has_last_Java_frame()) {
1768         frame f = last_frame();
1769         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1770           RegisterMap reg_map(this, false);
1771           frame compiled_frame = f.sender(&reg_map);
1772           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1773             Deoptimization::deoptimize(this, compiled_frame);
1774           }
1775         }
1776       }
1777 
1778       // Set async. pending exception in thread.
1779       set_pending_async_exception(java_throwable);
1780 
1781       if (log_is_enabled(Info, exceptions)) {
1782          ResourceMark rm;
1783         log_info(exceptions)("Pending Async. exception installed of type: %s",
1784                              InstanceKlass::cast(_pending_async_exception->klass())->external_name());
1785       }
1786       // for AbortVMOnException flag
1787       Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
1788     }
1789   }
1790 
1791 
1792   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1793   java_lang_Thread::set_interrupted(threadObj(), true);
1794   this->interrupt();
1795 }
1796 
1797 
1798 // External suspension mechanism.
1799 //
1800 // Guarantees on return (for a valid target thread):
1801 //   - Target thread will not execute any new bytecode.
1802 //   - Target thread will not enter any new monitors.
1803 //
1804 bool JavaThread::java_suspend() {
1805   ThreadsListHandle tlh;
1806   if (!tlh.includes(this)) {
1807     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, no suspension", p2i(this));
1808     return false;
1809   }
1810   return this->handshake_state()->suspend();
1811 }
1812 
1813 bool JavaThread::java_resume() {
1814   ThreadsListHandle tlh;
1815   if (!tlh.includes(this)) {
1816     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, nothing to resume", p2i(this));
1817     return false;
1818   }
1819   return this->handshake_state()->resume();
1820 }
1821 
1822 // Wait for another thread to perform object reallocation and relocking on behalf of
1823 // this thread.
1824 // Raw thread state transition to _thread_blocked and back again to the original
1825 // state before returning are performed. The current thread is required to
1826 // change to _thread_blocked in order to be seen to be safepoint/handshake safe
1827 // whilst suspended and only after becoming handshake safe, the other thread can
1828 // complete the handshake used to synchronize with this thread and then perform
1829 // the reallocation and relocking. We cannot use the thread state transition
1830 // helpers because we arrive here in various states and also because the helpers
1831 // indirectly call this method.  After leaving _thread_blocked we have to check
1832 // for safepoint/handshake, except if _thread_in_native. The thread is safe
1833 // without blocking then. Allowed states are enumerated in
1834 // SafepointSynchronize::block(). See also EscapeBarrier::sync_and_suspend_*()
1835 
1836 void JavaThread::wait_for_object_deoptimization() {
1837   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1838   assert(this == Thread::current(), "invariant");
1839   JavaThreadState state = thread_state();
1840 
1841   bool spin_wait = os::is_MP();
1842   do {
1843     set_thread_state(_thread_blocked);
1844     // Wait for object deoptimization if requested.
1845     if (spin_wait) {
1846       // A single deoptimization is typically very short. Microbenchmarks
1847       // showed 5% better performance when spinning.
1848       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1849       SpinYield spin(spin_limit);
1850       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1851         spin.wait();
1852       }
1853       // Spin just once
1854       spin_wait = false;
1855     } else {
1856       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1857       if (is_obj_deopt_suspend()) {
1858         ml.wait();
1859       }
1860     }
1861     // The current thread could have been suspended again. We have to check for
1862     // suspend after restoring the saved state. Without this the current thread
1863     // might return to _thread_in_Java and execute bytecode.
1864     set_thread_state_fence(state);
1865 
1866     if (state != _thread_in_native) {
1867       SafepointMechanism::process_if_requested(this);
1868     }
1869     // A handshake for obj. deoptimization suspend could have been processed so
1870     // we must check after processing.
1871   } while (is_obj_deopt_suspend());
1872 }
1873 
1874 #ifdef ASSERT
1875 // Verify the JavaThread has not yet been published in the Threads::list, and
1876 // hence doesn't need protection from concurrent access at this stage.
1877 void JavaThread::verify_not_published() {
1878   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1879   // since an unpublished JavaThread doesn't participate in the
1880   // Thread-SMR protocol for keeping a ThreadsList alive.
1881   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1882 }
1883 #endif
1884 
1885 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1886 // pending, when _suspend_flags is non-zero or when we need to process a stack
1887 // watermark. Also check for pending async exceptions (except unsafe access error).
1888 // Note only the native==>Java barriers can call this function when thread state
1889 // is _thread_in_native_trans.
1890 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1891   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1892   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1893 
1894   // Enable WXWrite: called directly from interpreter native wrapper.
1895   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1896 
1897   SafepointMechanism::process_if_requested_with_exit_check(thread, false /* check asyncs */);
1898 
1899   // After returning from native, it could be that the stack frames are not
1900   // yet safe to use. We catch such situations in the subsequent stack watermark
1901   // barrier, which will trap unsafe stack frames.
1902   StackWatermarkSet::before_unwind(thread);
1903 
1904   if (thread->has_async_exception_condition(false /* check unsafe access error */)) {
1905     // We are in _thread_in_native_trans state, don't handle unsafe
1906     // access error since that may block.
1907     thread->check_and_handle_async_exceptions();
1908   }
1909 }
1910 
1911 #ifndef PRODUCT
1912 // Deoptimization
1913 // Function for testing deoptimization
1914 void JavaThread::deoptimize() {
1915   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1916   bool deopt = false;           // Dump stack only if a deopt actually happens.
1917   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1918   // Iterate over all frames in the thread and deoptimize
1919   for (; !fst.is_done(); fst.next()) {
1920     if (fst.current()->can_be_deoptimized()) {
1921 
1922       if (only_at) {
1923         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1924         // consists of comma or carriage return separated numbers so
1925         // search for the current bci in that string.
1926         address pc = fst.current()->pc();
1927         nmethod* nm =  (nmethod*) fst.current()->cb();
1928         ScopeDesc* sd = nm->scope_desc_at(pc);
1929         char buffer[8];
1930         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1931         size_t len = strlen(buffer);
1932         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1933         while (found != NULL) {
1934           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1935               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1936             // Check that the bci found is bracketed by terminators.
1937             break;
1938           }
1939           found = strstr(found + 1, buffer);
1940         }
1941         if (!found) {
1942           continue;
1943         }
1944       }
1945 
1946       if (DebugDeoptimization && !deopt) {
1947         deopt = true; // One-time only print before deopt
1948         tty->print_cr("[BEFORE Deoptimization]");
1949         trace_frames();
1950         trace_stack();
1951       }
1952       Deoptimization::deoptimize(this, *fst.current());
1953     }
1954   }
1955 
1956   if (DebugDeoptimization && deopt) {
1957     tty->print_cr("[AFTER Deoptimization]");
1958     trace_frames();
1959   }
1960 }
1961 
1962 
1963 // Make zombies
1964 void JavaThread::make_zombies() {
1965   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1966     if (fst.current()->can_be_deoptimized()) {
1967       // it is a Java nmethod
1968       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1969       nm->make_not_entrant();
1970     }
1971   }
1972 }
1973 #endif // PRODUCT
1974 
1975 
1976 void JavaThread::deoptimize_marked_methods() {
1977   if (!has_last_Java_frame()) return;
1978   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1979   for (; !fst.is_done(); fst.next()) {
1980     if (fst.current()->should_be_deoptimized()) {
1981       Deoptimization::deoptimize(this, *fst.current());
1982     }
1983   }
1984 }
1985 
1986 #ifdef ASSERT
1987 void JavaThread::verify_frame_info() {
1988   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1989          (has_last_Java_frame() && java_call_counter() > 0),
1990          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1991          has_last_Java_frame() ? "true" : "false", java_call_counter());
1992 }
1993 #endif
1994 
1995 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1996   // Verify that the deferred card marks have been flushed.
1997   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1998 
1999   // Traverse the GCHandles
2000   Thread::oops_do_no_frames(f, cf);
2001 
2002   DEBUG_ONLY(verify_frame_info();)
2003 
2004   if (has_last_Java_frame()) {
2005     // Traverse the monitor chunks
2006     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2007       chunk->oops_do(f);
2008     }
2009   }
2010 
2011   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2012   // If we have deferred set_locals there might be oops waiting to be
2013   // written
2014   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
2015   if (list != NULL) {
2016     for (int i = 0; i < list->length(); i++) {
2017       list->at(i)->oops_do(f);
2018     }
2019   }
2020 
2021   // Traverse instance variables at the end since the GC may be moving things
2022   // around using this function
2023   f->do_oop((oop*) &_vm_result);
2024   f->do_oop((oop*) &_exception_oop);
2025   f->do_oop((oop*) &_pending_async_exception);
2026 #if INCLUDE_JVMCI
2027   f->do_oop((oop*) &_jvmci_reserved_oop0);
2028 #endif
2029 
2030   if (jvmti_thread_state() != NULL) {
2031     jvmti_thread_state()->oops_do(f, cf);
2032   }
2033 
2034   if (LockingMode == LM_LIGHTWEIGHT) {
2035     lock_stack().oops_do(f);
2036   }
2037 }
2038 
2039 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
2040   if (!has_last_Java_frame()) {
2041     return;
2042   }
2043   // Finish any pending lazy GC activity for the frames
2044   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
2045   // Traverse the execution stack
2046   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
2047     fst.current()->oops_do(f, cf, fst.register_map());
2048   }
2049 }
2050 
2051 #ifdef ASSERT
2052 void JavaThread::verify_states_for_handshake() {
2053   // This checks that the thread has a correct frame state during a handshake.
2054   verify_frame_info();
2055 }
2056 #endif
2057 
2058 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2059   DEBUG_ONLY(verify_frame_info();)
2060 
2061   if (has_last_Java_frame()) {
2062     // Traverse the execution stack
2063     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2064       fst.current()->nmethods_do(cf);
2065     }
2066   }
2067 
2068   if (jvmti_thread_state() != NULL) {
2069     jvmti_thread_state()->nmethods_do(cf);
2070   }
2071 }
2072 
2073 void JavaThread::metadata_do(MetadataClosure* f) {
2074   if (has_last_Java_frame()) {
2075     // Traverse the execution stack to call f() on the methods in the stack
2076     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2077       fst.current()->metadata_do(f);
2078     }
2079   } else if (is_Compiler_thread()) {
2080     // need to walk ciMetadata in current compile tasks to keep alive.
2081     CompilerThread* ct = (CompilerThread*)this;
2082     if (ct->env() != NULL) {
2083       ct->env()->metadata_do(f);
2084     }
2085     CompileTask* task = ct->task();
2086     if (task != NULL) {
2087       task->metadata_do(f);
2088     }
2089   }
2090 }
2091 
2092 // Printing
2093 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2094   switch (_thread_state) {
2095   case _thread_uninitialized:     return "_thread_uninitialized";
2096   case _thread_new:               return "_thread_new";
2097   case _thread_new_trans:         return "_thread_new_trans";
2098   case _thread_in_native:         return "_thread_in_native";
2099   case _thread_in_native_trans:   return "_thread_in_native_trans";
2100   case _thread_in_vm:             return "_thread_in_vm";
2101   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2102   case _thread_in_Java:           return "_thread_in_Java";
2103   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2104   case _thread_blocked:           return "_thread_blocked";
2105   case _thread_blocked_trans:     return "_thread_blocked_trans";
2106   default:                        return "unknown thread state";
2107   }
2108 }
2109 
2110 #ifndef PRODUCT
2111 void JavaThread::print_thread_state_on(outputStream *st) const {
2112   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2113 };
2114 #endif // PRODUCT
2115 
2116 // Called by Threads::print() for VM_PrintThreads operation
2117 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2118   st->print_raw("\"");
2119   st->print_raw(get_thread_name());
2120   st->print_raw("\" ");
2121   oop thread_oop = threadObj();
2122   if (thread_oop != NULL) {
2123     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2124     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2125     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2126   }
2127   Thread::print_on(st, print_extended_info);
2128   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2129   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2130   if (thread_oop != NULL) {
2131     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2132   }
2133 #ifndef PRODUCT
2134   _safepoint_state->print_on(st);
2135 #endif // PRODUCT
2136   if (is_Compiler_thread()) {
2137     CompileTask *task = ((CompilerThread*)this)->task();
2138     if (task != NULL) {
2139       st->print("   Compiling: ");
2140       task->print(st, NULL, true, false);
2141     } else {
2142       st->print("   No compile task");
2143     }
2144     st->cr();
2145   }
2146 }
2147 
2148 void JavaThread::print() const { print_on(tty); }
2149 
2150 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2151   st->print("%s", get_thread_name_string(buf, buflen));
2152 }
2153 
2154 // Called by fatal error handler. The difference between this and
2155 // JavaThread::print() is that we can't grab lock or allocate memory.
2156 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2157   st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2158   oop thread_obj = threadObj();
2159   if (thread_obj != NULL) {
2160     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2161   }
2162   st->print(" [");
2163   st->print("%s", _get_thread_state_name(_thread_state));
2164   if (osthread()) {
2165     st->print(", id=%d", osthread()->thread_id());
2166   }
2167   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2168             p2i(stack_end()), p2i(stack_base()));
2169   st->print("]");
2170 
2171   ThreadsSMRSupport::print_info_on(this, st);
2172   return;
2173 }
2174 
2175 
2176 // Verification
2177 
2178 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2179   // ignore if there is no stack
2180   if (!has_last_Java_frame()) return;
2181   // traverse the stack frames. Starts from top frame.
2182   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2183     frame* fr = fst.current();
2184     f(fr, fst.register_map());
2185   }
2186 }
2187 
2188 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2189 
2190 void JavaThread::verify() {
2191   // Verify oops in the thread.
2192   oops_do(&VerifyOopClosure::verify_oop, NULL);
2193 
2194   // Verify the stack frames.
2195   frames_do(frame_verify);
2196 }
2197 
2198 // CR 6300358 (sub-CR 2137150)
2199 // Most callers of this method assume that it can't return NULL but a
2200 // thread may not have a name whilst it is in the process of attaching to
2201 // the VM - see CR 6412693, and there are places where a JavaThread can be
2202 // seen prior to having its threadObj set (e.g., JNI attaching threads and
2203 // if vm exit occurs during initialization). These cases can all be accounted
2204 // for such that this method never returns NULL.
2205 const char* JavaThread::get_thread_name() const {
2206   if (Thread::is_JavaThread_protected(this)) {
2207     // The target JavaThread is protected so get_thread_name_string() is safe:
2208     return get_thread_name_string();
2209   }
2210 
2211   // The target JavaThread is not protected so we return the default:
2212   return Thread::name();
2213 }
2214 
2215 // Returns a non-NULL representation of this thread's name, or a suitable
2216 // descriptive string if there is no set name.
2217 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2218   const char* name_str;
2219   oop thread_obj = threadObj();
2220   if (thread_obj != NULL) {
2221     oop name = java_lang_Thread::name(thread_obj);
2222     if (name != NULL) {
2223       if (buf == NULL) {
2224         name_str = java_lang_String::as_utf8_string(name);
2225       } else {
2226         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2227       }
2228     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2229       name_str = "<no-name - thread is attaching>";
2230     } else {
2231       name_str = Thread::name();
2232     }
2233   } else {
2234     name_str = Thread::name();
2235   }
2236   assert(name_str != NULL, "unexpected NULL thread name");
2237   return name_str;
2238 }
2239 
2240 // Helper to extract the name from the thread oop for logging.
2241 const char* JavaThread::name_for(oop thread_obj) {
2242   assert(thread_obj != NULL, "precondition");
2243   oop name = java_lang_Thread::name(thread_obj);
2244   const char* name_str;
2245   if (name != NULL) {
2246     name_str = java_lang_String::as_utf8_string(name);
2247   } else {
2248     name_str = "<un-named>";
2249   }
2250   return name_str;
2251 }
2252 
2253 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2254 
2255   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2256   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
2257   // Link Java Thread object <-> C++ Thread
2258 
2259   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2260   // and put it into a new Handle.  The Handle "thread_oop" can then
2261   // be used to pass the C++ thread object to other methods.
2262 
2263   // Set the Java level thread object (jthread) field of the
2264   // new thread (a JavaThread *) to C++ thread object using the
2265   // "thread_oop" handle.
2266 
2267   // Set the thread field (a JavaThread *) of the
2268   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2269 
2270   Handle thread_oop(Thread::current(),
2271                     JNIHandles::resolve_non_null(jni_thread));
2272   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2273          "must be initialized");
2274   set_threadObj(thread_oop());
2275 
2276   if (prio == NoPriority) {
2277     prio = java_lang_Thread::priority(thread_oop());
2278     assert(prio != NoPriority, "A valid priority should be present");
2279   }
2280 
2281   // Push the Java priority down to the native thread; needs Threads_lock
2282   Thread::set_priority(this, prio);
2283 
2284   // Add the new thread to the Threads list and set it in motion.
2285   // We must have threads lock in order to call Threads::add.
2286   // It is crucial that we do not block before the thread is
2287   // added to the Threads list for if a GC happens, then the java_thread oop
2288   // will not be visited by GC.
2289   Threads::add(this);
2290   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2291   // on a ThreadsList. We don't want to wait for the release when the
2292   // Theads_lock is dropped somewhere in the caller since the JavaThread*
2293   // is already visible to JVM/TI via the ThreadsList.
2294   java_lang_Thread::release_set_thread(thread_oop(), this);
2295 }
2296 
2297 oop JavaThread::current_park_blocker() {
2298   // Support for JSR-166 locks
2299   oop thread_oop = threadObj();
2300   if (thread_oop != NULL) {
2301     return java_lang_Thread::park_blocker(thread_oop);
2302   }
2303   return NULL;
2304 }
2305 
2306 // Print current stack trace for checked JNI warnings and JNI fatal errors.
2307 // This is the external format, selecting the platform
2308 // as applicable, and allowing for a native-only stack.
2309 void JavaThread::print_jni_stack() {
2310   assert(this == JavaThread::current(), "Can't print stack of other threads");
2311   if (!has_last_Java_frame()) {
2312     ResourceMark rm(this);
2313     char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
2314     if (buf == nullptr) {
2315       tty->print_cr("Unable to print native stack - out of memory");
2316       return;
2317     }
2318     frame f = os::current_frame();
2319     VMError::print_native_stack(tty, f, this,
2320                                 buf, O_BUFLEN);
2321   } else {
2322     print_stack_on(tty);
2323   }
2324 }
2325 
2326 void JavaThread::print_stack_on(outputStream* st) {
2327   if (!has_last_Java_frame()) return;
2328 
2329   Thread* current_thread = Thread::current();
2330   ResourceMark rm(current_thread);
2331   HandleMark hm(current_thread);
2332 
2333   RegisterMap reg_map(this);
2334   vframe* start_vf = last_java_vframe(&reg_map);
2335   int count = 0;
2336   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
2337     if (f->is_java_frame()) {
2338       javaVFrame* jvf = javaVFrame::cast(f);
2339       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2340 
2341       // Print out lock information
2342       if (JavaMonitorsInStackTrace) {
2343         jvf->print_lock_info_on(st, count);
2344       }
2345     } else {
2346       // Ignore non-Java frames
2347     }
2348 
2349     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
2350     count++;
2351     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
2352   }
2353 }
2354 
2355 
2356 // JVMTI PopFrame support
2357 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2358   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2359   if (in_bytes(size_in_bytes) != 0) {
2360     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2361     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2362     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2363   }
2364 }
2365 
2366 void* JavaThread::popframe_preserved_args() {
2367   return _popframe_preserved_args;
2368 }
2369 
2370 ByteSize JavaThread::popframe_preserved_args_size() {
2371   return in_ByteSize(_popframe_preserved_args_size);
2372 }
2373 
2374 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2375   int sz = in_bytes(popframe_preserved_args_size());
2376   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2377   return in_WordSize(sz / wordSize);
2378 }
2379 
2380 void JavaThread::popframe_free_preserved_args() {
2381   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2382   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
2383   _popframe_preserved_args = NULL;
2384   _popframe_preserved_args_size = 0;
2385 }
2386 
2387 #ifndef PRODUCT
2388 
2389 void JavaThread::trace_frames() {
2390   tty->print_cr("[Describe stack]");
2391   int frame_no = 1;
2392   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2393     tty->print("  %d. ", frame_no++);
2394     fst.current()->print_value_on(tty, this);
2395     tty->cr();
2396   }
2397 }
2398 
2399 class PrintAndVerifyOopClosure: public OopClosure {
2400  protected:
2401   template <class T> inline void do_oop_work(T* p) {
2402     oop obj = RawAccess<>::oop_load(p);
2403     if (obj == NULL) return;
2404     tty->print(INTPTR_FORMAT ": ", p2i(p));
2405     if (oopDesc::is_oop_or_null(obj)) {
2406       if (obj->is_objArray()) {
2407         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
2408       } else {
2409         obj->print();
2410       }
2411     } else {
2412       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
2413     }
2414     tty->cr();
2415   }
2416  public:
2417   virtual void do_oop(oop* p) { do_oop_work(p); }
2418   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
2419 };
2420 
2421 #ifdef ASSERT
2422 // Print or validate the layout of stack frames
2423 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2424   ResourceMark rm;
2425   PreserveExceptionMark pm(this);
2426   FrameValues values;
2427   int frame_no = 0;
2428   for (StackFrameStream fst(this, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2429     fst.current()->describe(values, ++frame_no);
2430     if (depth == frame_no) break;
2431   }
2432   if (validate_only) {
2433     values.validate();
2434   } else {
2435     tty->print_cr("[Describe stack layout]");
2436     values.print(this);
2437   }
2438 }
2439 #endif
2440 
2441 void JavaThread::trace_stack_from(vframe* start_vf) {
2442   ResourceMark rm;
2443   int vframe_no = 1;
2444   for (vframe* f = start_vf; f; f = f->sender()) {
2445     if (f->is_java_frame()) {
2446       javaVFrame::cast(f)->print_activation(vframe_no++);
2447     } else {
2448       f->print();
2449     }
2450     if (vframe_no > StackPrintLimit) {
2451       tty->print_cr("...<more frames>...");
2452       return;
2453     }
2454   }
2455 }
2456 
2457 
2458 void JavaThread::trace_stack() {
2459   if (!has_last_Java_frame()) return;
2460   Thread* current_thread = Thread::current();
2461   ResourceMark rm(current_thread);
2462   HandleMark hm(current_thread);
2463   RegisterMap reg_map(this);
2464   trace_stack_from(last_java_vframe(&reg_map));
2465 }
2466 
2467 
2468 #endif // PRODUCT
2469 
2470 
2471 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2472   assert(reg_map != NULL, "a map must be given");
2473   frame f = last_frame();
2474   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2475     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2476   }
2477   return NULL;
2478 }
2479 
2480 
2481 Klass* JavaThread::security_get_caller_class(int depth) {
2482   vframeStream vfst(this);
2483   vfst.security_get_caller_frame(depth);
2484   if (!vfst.at_end()) {
2485     return vfst.method()->method_holder();
2486   }
2487   return NULL;
2488 }
2489 
2490 // java.lang.Thread.sleep support
2491 // Returns true if sleep time elapsed as expected, and false
2492 // if the thread was interrupted.
2493 bool JavaThread::sleep(jlong millis) {
2494   assert(this == Thread::current(),  "thread consistency check");
2495 
2496   ParkEvent * const slp = this->_SleepEvent;
2497   // Because there can be races with thread interruption sending an unpark()
2498   // to the event, we explicitly reset it here to avoid an immediate return.
2499   // The actual interrupt state will be checked before we park().
2500   slp->reset();
2501   // Thread interruption establishes a happens-before ordering in the
2502   // Java Memory Model, so we need to ensure we synchronize with the
2503   // interrupt state.
2504   OrderAccess::fence();
2505 
2506   jlong prevtime = os::javaTimeNanos();
2507 
2508   for (;;) {
2509     // interruption has precedence over timing out
2510     if (this->is_interrupted(true)) {
2511       return false;
2512     }
2513 
2514     if (millis <= 0) {
2515       return true;
2516     }
2517 
2518     {
2519       ThreadBlockInVM tbivm(this);
2520       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2521       slp->park(millis);
2522     }
2523 
2524     // Update elapsed time tracking
2525     jlong newtime = os::javaTimeNanos();
2526     if (newtime - prevtime < 0) {
2527       // time moving backwards, should only happen if no monotonic clock
2528       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2529       assert(false,
2530              "unexpected time moving backwards detected in JavaThread::sleep()");
2531     } else {
2532       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2533     }
2534     prevtime = newtime;
2535   }
2536 }
2537 
2538 
2539 // ======= Threads ========
2540 
2541 // The Threads class links together all active threads, and provides
2542 // operations over all threads. It is protected by the Threads_lock,
2543 // which is also used in other global contexts like safepointing.
2544 // ThreadsListHandles are used to safely perform operations on one
2545 // or more threads without the risk of the thread exiting during the
2546 // operation.
2547 //
2548 // Note: The Threads_lock is currently more widely used than we
2549 // would like. We are actively migrating Threads_lock uses to other
2550 // mechanisms in order to reduce Threads_lock contention.
2551 
2552 int         Threads::_number_of_threads = 0;
2553 int         Threads::_number_of_non_daemon_threads = 0;
2554 int         Threads::_return_code = 0;
2555 uintx       Threads::_thread_claim_token = 1; // Never zero.
2556 size_t      JavaThread::_stack_size_at_create = 0;
2557 
2558 #ifdef ASSERT
2559 bool        Threads::_vm_complete = false;
2560 #endif
2561 
2562 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
2563   Prefetch::read((void*)addr, prefetch_interval);
2564   return *addr;
2565 }
2566 
2567 // Possibly the ugliest for loop the world has seen. C++ does not allow
2568 // multiple types in the declaration section of the for loop. In this case
2569 // we are only dealing with pointers and hence can cast them. It looks ugly
2570 // but macros are ugly and therefore it's fine to make things absurdly ugly.
2571 #define DO_JAVA_THREADS(LIST, X)                                                                                          \
2572     for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes,                           \
2573              *MACRO_list = (JavaThread*)(LIST),                                                                           \
2574              **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(),  \
2575              **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(),                                     \
2576              *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval);                 \
2577          MACRO_current_p != MACRO_end;                                                                                    \
2578          MACRO_current_p++,                                                                                               \
2579              X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
2580 
2581 // All JavaThreads
2582 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
2583 
2584 // All NonJavaThreads (i.e., every non-JavaThread in the system).
2585 void Threads::non_java_threads_do(ThreadClosure* tc) {
2586   NoSafepointVerifier nsv;
2587   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
2588     tc->do_thread(njti.current());
2589   }
2590 }
2591 
2592 // All JavaThreads
2593 void Threads::java_threads_do(ThreadClosure* tc) {
2594   assert_locked_or_safepoint(Threads_lock);
2595   // ALL_JAVA_THREADS iterates through all JavaThreads.
2596   ALL_JAVA_THREADS(p) {
2597     tc->do_thread(p);
2598   }
2599 }
2600 
2601 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
2602   assert_locked_or_safepoint(Threads_lock);
2603   java_threads_do(tc);
2604   tc->do_thread(VMThread::vm_thread());
2605 }
2606 
2607 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
2608 void Threads::threads_do(ThreadClosure* tc) {
2609   assert_locked_or_safepoint(Threads_lock);
2610   java_threads_do(tc);
2611   non_java_threads_do(tc);
2612 }
2613 
2614 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
2615   uintx claim_token = Threads::thread_claim_token();
2616   ALL_JAVA_THREADS(p) {
2617     if (p->claim_threads_do(is_par, claim_token)) {
2618       tc->do_thread(p);
2619     }
2620   }
2621   VMThread* vmt = VMThread::vm_thread();
2622   if (vmt->claim_threads_do(is_par, claim_token)) {
2623     tc->do_thread(vmt);
2624   }
2625 }
2626 
2627 // The system initialization in the library has three phases.
2628 //
2629 // Phase 1: java.lang.System class initialization
2630 //     java.lang.System is a primordial class loaded and initialized
2631 //     by the VM early during startup.  java.lang.System.<clinit>
2632 //     only does registerNatives and keeps the rest of the class
2633 //     initialization work later until thread initialization completes.
2634 //
2635 //     System.initPhase1 initializes the system properties, the static
2636 //     fields in, out, and err. Set up java signal handlers, OS-specific
2637 //     system settings, and thread group of the main thread.
2638 static void call_initPhase1(TRAPS) {
2639   Klass* klass = vmClasses::System_klass();
2640   JavaValue result(T_VOID);
2641   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
2642                                          vmSymbols::void_method_signature(), CHECK);
2643 }
2644 
2645 // Phase 2. Module system initialization
2646 //     This will initialize the module system.  Only java.base classes
2647 //     can be loaded until phase 2 completes.
2648 //
2649 //     Call System.initPhase2 after the compiler initialization and jsr292
2650 //     classes get initialized because module initialization runs a lot of java
2651 //     code, that for performance reasons, should be compiled.  Also, this will
2652 //     enable the startup code to use lambda and other language features in this
2653 //     phase and onward.
2654 //
2655 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
2656 static void call_initPhase2(TRAPS) {
2657   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
2658 
2659   Klass* klass = vmClasses::System_klass();
2660 
2661   JavaValue result(T_INT);
2662   JavaCallArguments args;
2663   args.push_int(DisplayVMOutputToStderr);
2664   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
2665   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
2666                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
2667   if (result.get_jint() != JNI_OK) {
2668     vm_exit_during_initialization(); // no message or exception
2669   }
2670 
2671   universe_post_module_init();
2672 }
2673 
2674 // Phase 3. final setup - set security manager, system class loader and TCCL
2675 //
2676 //     This will instantiate and set the security manager, set the system class
2677 //     loader as well as the thread context class loader.  The security manager
2678 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
2679 //     other modules or the application's classpath.
2680 static void call_initPhase3(TRAPS) {
2681   Klass* klass = vmClasses::System_klass();
2682   JavaValue result(T_VOID);
2683   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
2684                                          vmSymbols::void_method_signature(), CHECK);
2685 }
2686 
2687 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
2688   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
2689 
2690   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2691     create_vm_init_libraries();
2692   }
2693 
2694   initialize_class(vmSymbols::java_lang_String(), CHECK);
2695 
2696   // Inject CompactStrings value after the static initializers for String ran.
2697   java_lang_String::set_compact_strings(CompactStrings);
2698 
2699   // Initialize java_lang.System (needed before creating the thread)
2700   initialize_class(vmSymbols::java_lang_System(), CHECK);
2701   // The VM creates & returns objects of this class. Make sure it's initialized.
2702   initialize_class(vmSymbols::java_lang_Class(), CHECK);
2703   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
2704   Handle thread_group = create_initial_thread_group(CHECK);
2705   Universe::set_main_thread_group(thread_group());
2706   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
2707   create_initial_thread(thread_group, main_thread, CHECK);
2708 
2709   // The VM creates objects of this class.
2710   initialize_class(vmSymbols::java_lang_Module(), CHECK);
2711 
2712 #ifdef ASSERT
2713   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
2714   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
2715 #endif
2716 
2717   // initialize the hardware-specific constants needed by Unsafe
2718   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
2719   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
2720 
2721   // The VM preresolves methods to these classes. Make sure that they get initialized
2722   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
2723   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
2724 
2725   // Phase 1 of the system initialization in the library, java.lang.System class initialization
2726   call_initPhase1(CHECK);
2727 
2728   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
2729   // Some values are actually configure-time constants but some can be set via the jlink tool and
2730   // so must be read dynamically. We treat them all the same.
2731   InstanceKlass* ik = SystemDictionary::find_instance_klass(vmSymbols::java_lang_VersionProps(),
2732                                                             Handle(), Handle());
2733   {
2734     ResourceMark rm(main_thread);
2735     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
2736 
2737     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
2738 
2739     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
2740 
2741     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
2742 
2743     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
2744   }
2745 
2746   // an instance of OutOfMemory exception has been allocated earlier
2747   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
2748   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
2749   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
2750   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
2751   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
2752   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
2753   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
2754   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
2755 }
2756 
2757 void Threads::initialize_jsr292_core_classes(TRAPS) {
2758   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
2759 
2760   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
2761   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
2762   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
2763   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
2764 }
2765 
2766 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2767   extern void JDK_Version_init();
2768 
2769   // Preinitialize version info.
2770   VM_Version::early_initialize();
2771 
2772   // Check version
2773   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2774 
2775   // Initialize library-based TLS
2776   ThreadLocalStorage::init();
2777 
2778   // Initialize the output stream module
2779   ostream_init();
2780 
2781   // Process java launcher properties.
2782   Arguments::process_sun_java_launcher_properties(args);
2783 
2784   // Initialize the os module
2785   os::init();
2786 
2787   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
2788 
2789   // Record VM creation timing statistics
2790   TraceVmCreationTime create_vm_timer;
2791   create_vm_timer.start();
2792 
2793   // Initialize system properties.
2794   Arguments::init_system_properties();
2795 
2796   // So that JDK version can be used as a discriminator when parsing arguments
2797   JDK_Version_init();
2798 
2799   // Update/Initialize System properties after JDK version number is known
2800   Arguments::init_version_specific_system_properties();
2801 
2802   // Make sure to initialize log configuration *before* parsing arguments
2803   LogConfiguration::initialize(create_vm_timer.begin_time());
2804 
2805   // Parse arguments
2806   // Note: this internally calls os::init_container_support()
2807   jint parse_result = Arguments::parse(args);
2808   if (parse_result != JNI_OK) return parse_result;
2809 
2810 #if INCLUDE_NMT
2811   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
2812   MemTracker::initialize();
2813 #endif // INCLUDE_NMT
2814 
2815   os::init_before_ergo();
2816 
2817   jint ergo_result = Arguments::apply_ergo();
2818   if (ergo_result != JNI_OK) return ergo_result;
2819 
2820   // Final check of all ranges after ergonomics which may change values.
2821   if (!JVMFlagLimit::check_all_ranges()) {
2822     return JNI_EINVAL;
2823   }
2824 
2825   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
2826   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
2827   if (!constraint_result) {
2828     return JNI_EINVAL;
2829   }
2830 
2831   if (PauseAtStartup) {
2832     os::pause();
2833   }
2834 
2835   HOTSPOT_VM_INIT_BEGIN();
2836 
2837   // Timing (must come after argument parsing)
2838   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
2839 
2840   // Initialize the os module after parsing the args
2841   jint os_init_2_result = os::init_2();
2842   if (os_init_2_result != JNI_OK) return os_init_2_result;
2843 
2844 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
2845   // Initialize assert poison page mechanism.
2846   if (ShowRegistersOnAssert) {
2847     initialize_assert_poison();
2848   }
2849 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
2850 
2851   SafepointMechanism::initialize();
2852 
2853   jint adjust_after_os_result = Arguments::adjust_after_os();
2854   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
2855 
2856   // Initialize output stream logging
2857   ostream_init_log();
2858 
2859   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2860   // Must be before create_vm_init_agents()
2861   if (Arguments::init_libraries_at_startup()) {
2862     convert_vm_init_libraries_to_agents();
2863   }
2864 
2865   // Should happen before any agent attaches and pokes into vmStructs
2866 #if INCLUDE_VM_STRUCTS
2867   if (UseCompactObjectHeaders) {
2868     VMStructs::compact_headers_overrides();
2869   }
2870 #endif
2871 
2872   // Launch -agentlib/-agentpath and converted -Xrun agents
2873   if (Arguments::init_agents_at_startup()) {
2874     create_vm_init_agents();
2875   }
2876 
2877   // Initialize Threads state
2878   _number_of_threads = 0;
2879   _number_of_non_daemon_threads = 0;
2880 
2881   // Initialize global data structures and create system classes in heap
2882   vm_init_globals();
2883 
2884 #if INCLUDE_JVMCI
2885   if (JVMCICounterSize > 0) {
2886     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
2887     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
2888   } else {
2889     JavaThread::_jvmci_old_thread_counters = NULL;
2890   }
2891 #endif // INCLUDE_JVMCI
2892 
2893   // Initialize OopStorage for threadObj
2894   _thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
2895 
2896   // Attach the main thread to this os thread
2897   JavaThread* main_thread = new JavaThread();
2898   main_thread->set_thread_state(_thread_in_vm);
2899   main_thread->initialize_thread_current();
2900   // must do this before set_active_handles
2901   main_thread->record_stack_base_and_size();
2902   main_thread->register_thread_stack_with_NMT();
2903   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2904   MACOS_AARCH64_ONLY(main_thread->init_wx());
2905 
2906   if (!main_thread->set_as_starting_thread()) {
2907     vm_shutdown_during_initialization(
2908                                       "Failed necessary internal allocation. Out of swap space");
2909     main_thread->smr_delete();
2910     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2911     return JNI_ENOMEM;
2912   }
2913 
2914   // Enable guard page *after* os::create_main_thread(), otherwise it would
2915   // crash Linux VM, see notes in os_linux.cpp.
2916   main_thread->stack_overflow_state()->create_stack_guard_pages();
2917 
2918   // Initialize Java-Level synchronization subsystem
2919   ObjectMonitor::Initialize();
2920   ObjectSynchronizer::initialize();
2921 
2922   // Initialize global modules
2923   jint status = init_globals();
2924   if (status != JNI_OK) {
2925     main_thread->smr_delete();
2926     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2927     return status;
2928   }
2929 
2930   JFR_ONLY(Jfr::on_create_vm_1();)
2931 
2932   // Should be done after the heap is fully created
2933   main_thread->cache_global_variables();
2934 
2935   { MutexLocker mu(Threads_lock);
2936     Threads::add(main_thread);
2937   }
2938 
2939   // Any JVMTI raw monitors entered in onload will transition into
2940   // real raw monitor. VM is setup enough here for raw monitor enter.
2941   JvmtiExport::transition_pending_onload_raw_monitors();
2942 
2943   // Create the VMThread
2944   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
2945 
2946     VMThread::create();
2947     Thread* vmthread = VMThread::vm_thread();
2948 
2949     if (!os::create_thread(vmthread, os::vm_thread)) {
2950       vm_exit_during_initialization("Cannot create VM thread. "
2951                                     "Out of system resources.");
2952     }
2953 
2954     // Wait for the VM thread to become ready, and VMThread::run to initialize
2955     // Monitors can have spurious returns, must always check another state flag
2956     {
2957       MonitorLocker ml(Notify_lock);
2958       os::start_thread(vmthread);
2959       while (vmthread->active_handles() == NULL) {
2960         ml.wait();
2961       }
2962     }
2963   }
2964 
2965   assert(Universe::is_fully_initialized(), "not initialized");
2966   if (VerifyDuringStartup) {
2967     // Make sure we're starting with a clean slate.
2968     VM_Verify verify_op;
2969     VMThread::execute(&verify_op);
2970   }
2971 
2972   // We need this to update the java.vm.info property in case any flags used
2973   // to initially define it have been changed. This is needed for both CDS
2974   // since UseSharedSpaces may be changed after java.vm.info
2975   // is initially computed. See Abstract_VM_Version::vm_info_string().
2976   // This update must happen before we initialize the java classes, but
2977   // after any initialization logic that might modify the flags.
2978   Arguments::update_vm_info_property(VM_Version::vm_info_string());
2979 
2980   JavaThread* THREAD = JavaThread::current(); // For exception macros.
2981   HandleMark hm(THREAD);
2982 
2983   // Always call even when there are not JVMTI environments yet, since environments
2984   // may be attached late and JVMTI must track phases of VM execution
2985   JvmtiExport::enter_early_start_phase();
2986 
2987   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2988   JvmtiExport::post_early_vm_start();
2989 
2990   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
2991 
2992   quicken_jni_functions();
2993 
2994   // No more stub generation allowed after that point.
2995   StubCodeDesc::freeze();
2996 
2997   // Set flag that basic initialization has completed. Used by exceptions and various
2998   // debug stuff, that does not work until all basic classes have been initialized.
2999   set_init_completed();
3000 
3001   LogConfiguration::post_initialize();
3002   Metaspace::post_initialize();
3003 
3004   HOTSPOT_VM_INIT_END();
3005 
3006   // record VM initialization completion time
3007 #if INCLUDE_MANAGEMENT
3008   Management::record_vm_init_completed();
3009 #endif // INCLUDE_MANAGEMENT
3010 
3011   // Signal Dispatcher needs to be started before VMInit event is posted
3012   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3013 
3014   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3015   if (!DisableAttachMechanism) {
3016     AttachListener::vm_start();
3017     if (StartAttachListener || AttachListener::init_at_startup()) {
3018       AttachListener::init();
3019     }
3020   }
3021 
3022   // Launch -Xrun agents
3023   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3024   // back-end can launch with -Xdebug -Xrunjdwp.
3025   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3026     create_vm_init_libraries();
3027   }
3028 
3029   Chunk::start_chunk_pool_cleaner_task();
3030 
3031   // Start the service thread
3032   // The service thread enqueues JVMTI deferred events and does various hashtable
3033   // and other cleanups.  Needs to start before the compilers start posting events.
3034   ServiceThread::initialize();
3035 
3036   // Start the monitor deflation thread:
3037   MonitorDeflationThread::initialize();
3038 
3039   // initialize compiler(s)
3040 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3041 #if INCLUDE_JVMCI
3042   bool force_JVMCI_intialization = false;
3043   if (EnableJVMCI) {
3044     // Initialize JVMCI eagerly when it is explicitly requested.
3045     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
3046     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
3047 
3048     if (!force_JVMCI_intialization) {
3049       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3050       // compilations via JVMCI will not actually block until JVMCI is initialized.
3051       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3052     }
3053   }
3054 #endif
3055   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3056   // Postpone completion of compiler initialization to after JVMCI
3057   // is initialized to avoid timeouts of blocking compilations.
3058   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3059     CompileBroker::compilation_init_phase2();
3060   }
3061 #endif
3062 
3063   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3064   // It is done after compilers are initialized, because otherwise compilations of
3065   // signature polymorphic MH intrinsics can be missed
3066   // (see SystemDictionary::find_method_handle_intrinsic).
3067   initialize_jsr292_core_classes(CHECK_JNI_ERR);
3068 
3069   // This will initialize the module system.  Only java.base classes can be
3070   // loaded until phase 2 completes
3071   call_initPhase2(CHECK_JNI_ERR);
3072 
3073   JFR_ONLY(Jfr::on_create_vm_2();)
3074 
3075   // Always call even when there are not JVMTI environments yet, since environments
3076   // may be attached late and JVMTI must track phases of VM execution
3077   JvmtiExport::enter_start_phase();
3078 
3079   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3080   JvmtiExport::post_vm_start();
3081 
3082   // Final system initialization including security manager and system class loader
3083   call_initPhase3(CHECK_JNI_ERR);
3084 
3085   // cache the system and platform class loaders
3086   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3087 
3088 #if INCLUDE_CDS
3089   // capture the module path info from the ModuleEntryTable
3090   ClassLoader::initialize_module_path(THREAD);
3091   if (HAS_PENDING_EXCEPTION) {
3092     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
3093     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
3094   }
3095 #endif
3096 
3097 #if INCLUDE_JVMCI
3098   if (force_JVMCI_intialization) {
3099     JVMCI::initialize_compiler(CHECK_JNI_ERR);
3100     CompileBroker::compilation_init_phase2();
3101   }
3102 #endif
3103 
3104   if (NativeHeapTrimmer::enabled()) {
3105     NativeHeapTrimmer::initialize();
3106   }
3107 
3108   // Always call even when there are not JVMTI environments yet, since environments
3109   // may be attached late and JVMTI must track phases of VM execution
3110   JvmtiExport::enter_live_phase();
3111 
3112   // Make perfmemory accessible
3113   PerfMemory::set_accessible(true);
3114 
3115   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3116   JvmtiExport::post_vm_initialized();
3117 
3118   JFR_ONLY(Jfr::on_create_vm_3();)
3119 
3120 #if INCLUDE_MANAGEMENT
3121   Management::initialize(THREAD);
3122 
3123   if (HAS_PENDING_EXCEPTION) {
3124     // management agent fails to start possibly due to
3125     // configuration problem and is responsible for printing
3126     // stack trace if appropriate. Simply exit VM.
3127     vm_exit(1);
3128   }
3129 #endif // INCLUDE_MANAGEMENT
3130 
3131   StatSampler::engage();
3132   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3133 
3134   BiasedLocking::init();
3135 
3136 #if INCLUDE_RTM_OPT
3137   RTMLockingCounters::init();
3138 #endif
3139 
3140   call_postVMInitHook(THREAD);
3141   // The Java side of PostVMInitHook.run must deal with all
3142   // exceptions and provide means of diagnosis.
3143   if (HAS_PENDING_EXCEPTION) {
3144     CLEAR_PENDING_EXCEPTION;
3145   }
3146 
3147   {
3148     MutexLocker ml(PeriodicTask_lock);
3149     // Make sure the WatcherThread can be started by WatcherThread::start()
3150     // or by dynamic enrollment.
3151     WatcherThread::make_startable();
3152     // Start up the WatcherThread if there are any periodic tasks
3153     // NOTE:  All PeriodicTasks should be registered by now. If they
3154     //   aren't, late joiners might appear to start slowly (we might
3155     //   take a while to process their first tick).
3156     if (PeriodicTask::num_tasks() > 0) {
3157       WatcherThread::start();
3158     }
3159   }
3160 
3161   create_vm_timer.end();
3162 #ifdef ASSERT
3163   _vm_complete = true;
3164 #endif
3165 
3166   if (DumpSharedSpaces) {
3167     MetaspaceShared::preload_and_dump();
3168     ShouldNotReachHere();
3169   }
3170 
3171   return JNI_OK;
3172 }
3173 
3174 // type for the Agent_OnLoad and JVM_OnLoad entry points
3175 extern "C" {
3176   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3177 }
3178 // Find a command line agent library and return its entry point for
3179 //         -agentlib:  -agentpath:   -Xrun
3180 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3181 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3182                                     const char *on_load_symbols[],
3183                                     size_t num_symbol_entries) {
3184   OnLoadEntry_t on_load_entry = NULL;
3185   void *library = NULL;
3186 
3187   if (!agent->valid()) {
3188     char buffer[JVM_MAXPATHLEN];
3189     char ebuf[1024] = "";
3190     const char *name = agent->name();
3191     const char *msg = "Could not find agent library ";
3192 
3193     // First check to see if agent is statically linked into executable
3194     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3195       library = agent->os_lib();
3196     } else if (agent->is_absolute_path()) {
3197       library = os::dll_load(name, ebuf, sizeof ebuf);
3198       if (library == NULL) {
3199         const char *sub_msg = " in absolute path, with error: ";
3200         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3201         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3202         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3203         // If we can't find the agent, exit.
3204         vm_exit_during_initialization(buf, NULL);
3205         FREE_C_HEAP_ARRAY(char, buf);
3206       }
3207     } else {
3208       // Try to load the agent from the standard dll directory
3209       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3210                              name)) {
3211         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3212       }
3213       if (library == NULL) { // Try the library path directory.
3214         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3215           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3216         }
3217         if (library == NULL) {
3218           const char *sub_msg = " on the library path, with error: ";
3219           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3220 
3221           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3222                        strlen(ebuf) + strlen(sub_msg2) + 1;
3223           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3224           if (!agent->is_instrument_lib()) {
3225             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3226           } else {
3227             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
3228           }
3229           // If we can't find the agent, exit.
3230           vm_exit_during_initialization(buf, NULL);
3231           FREE_C_HEAP_ARRAY(char, buf);
3232         }
3233       }
3234     }
3235     agent->set_os_lib(library);
3236     agent->set_valid();
3237   }
3238 
3239   // Find the OnLoad function.
3240   on_load_entry =
3241     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3242                                                           false,
3243                                                           on_load_symbols,
3244                                                           num_symbol_entries));
3245   return on_load_entry;
3246 }
3247 
3248 // Find the JVM_OnLoad entry point
3249 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3250   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3251   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3252 }
3253 
3254 // Find the Agent_OnLoad entry point
3255 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3256   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3257   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3258 }
3259 
3260 // For backwards compatibility with -Xrun
3261 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3262 // treated like -agentpath:
3263 // Must be called before agent libraries are created
3264 void Threads::convert_vm_init_libraries_to_agents() {
3265   AgentLibrary* agent;
3266   AgentLibrary* next;
3267 
3268   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3269     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3270     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3271 
3272     // If there is an JVM_OnLoad function it will get called later,
3273     // otherwise see if there is an Agent_OnLoad
3274     if (on_load_entry == NULL) {
3275       on_load_entry = lookup_agent_on_load(agent);
3276       if (on_load_entry != NULL) {
3277         // switch it to the agent list -- so that Agent_OnLoad will be called,
3278         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3279         Arguments::convert_library_to_agent(agent);
3280       } else {
3281         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3282       }
3283     }
3284   }
3285 }
3286 
3287 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3288 // Invokes Agent_OnLoad
3289 // Called very early -- before JavaThreads exist
3290 void Threads::create_vm_init_agents() {
3291   extern struct JavaVM_ main_vm;
3292   AgentLibrary* agent;
3293 
3294   JvmtiExport::enter_onload_phase();
3295 
3296   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3297     // CDS dumping does not support native JVMTI agent.
3298     // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
3299     if (Arguments::is_dumping_archive()) {
3300       if(!agent->is_instrument_lib()) {
3301         vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
3302       } else if (!AllowArchivingWithJavaAgent) {
3303         vm_exit_during_cds_dumping(
3304           "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
3305       }
3306     }
3307 
3308     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3309 
3310     if (on_load_entry != NULL) {
3311       // Invoke the Agent_OnLoad function
3312       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3313       if (err != JNI_OK) {
3314         vm_exit_during_initialization("agent library failed to init", agent->name());
3315       }
3316     } else {
3317       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3318     }
3319   }
3320 
3321   JvmtiExport::enter_primordial_phase();
3322 }
3323 
3324 extern "C" {
3325   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3326 }
3327 
3328 void Threads::shutdown_vm_agents() {
3329   // Send any Agent_OnUnload notifications
3330   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3331   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3332   extern struct JavaVM_ main_vm;
3333   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3334 
3335     // Find the Agent_OnUnload function.
3336     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3337                                                    os::find_agent_function(agent,
3338                                                    false,
3339                                                    on_unload_symbols,
3340                                                    num_symbol_entries));
3341 
3342     // Invoke the Agent_OnUnload function
3343     if (unload_entry != NULL) {
3344       JavaThread* thread = JavaThread::current();
3345       ThreadToNativeFromVM ttn(thread);
3346       HandleMark hm(thread);
3347       (*unload_entry)(&main_vm);
3348     }
3349   }
3350 }
3351 
3352 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3353 // Invokes JVM_OnLoad
3354 void Threads::create_vm_init_libraries() {
3355   extern struct JavaVM_ main_vm;
3356   AgentLibrary* agent;
3357 
3358   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3359     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3360 
3361     if (on_load_entry != NULL) {
3362       // Invoke the JVM_OnLoad function
3363       JavaThread* thread = JavaThread::current();
3364       ThreadToNativeFromVM ttn(thread);
3365       HandleMark hm(thread);
3366       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3367       if (err != JNI_OK) {
3368         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3369       }
3370     } else {
3371       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3372     }
3373   }
3374 }
3375 
3376 
3377 // Last thread running calls java.lang.Shutdown.shutdown()
3378 void JavaThread::invoke_shutdown_hooks() {
3379   HandleMark hm(this);
3380 
3381   // We could get here with a pending exception, if so clear it now or
3382   // it will cause MetaspaceShared::link_and_cleanup_shared_classes to
3383   // fail for dynamic dump.
3384   if (this->has_pending_exception()) {
3385     this->clear_pending_exception();
3386   }
3387 
3388 #if INCLUDE_CDS
3389   // Link all classes for dynamic CDS dumping before vm exit.
3390   // Same operation is being done in JVM_BeforeHalt for handling the
3391   // case where the application calls System.exit().
3392   if (DynamicDumpSharedSpaces) {
3393     DynamicArchive::prepare_for_dynamic_dumping_at_exit();
3394   }
3395 #endif
3396 
3397   EXCEPTION_MARK;
3398   Klass* shutdown_klass =
3399     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3400                                       THREAD);
3401   if (shutdown_klass != NULL) {
3402     // SystemDictionary::resolve_or_null will return null if there was
3403     // an exception.  If we cannot load the Shutdown class, just don't
3404     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3405     // won't be run.  Note that if a shutdown hook was registered,
3406     // the Shutdown class would have already been loaded
3407     // (Runtime.addShutdownHook will load it).
3408     JavaValue result(T_VOID);
3409     JavaCalls::call_static(&result,
3410                            shutdown_klass,
3411                            vmSymbols::shutdown_name(),
3412                            vmSymbols::void_method_signature(),
3413                            THREAD);
3414   }
3415   CLEAR_PENDING_EXCEPTION;
3416 }
3417 
3418 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3419 // the program falls off the end of main(). Another VM exit path is through
3420 // vm_exit() when the program calls System.exit() to return a value or when
3421 // there is a serious error in VM. The two shutdown paths are not exactly
3422 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3423 // and VM_Exit op at VM level.
3424 //
3425 // Shutdown sequence:
3426 //   + Shutdown native memory tracking if it is on
3427 //   + Wait until we are the last non-daemon thread to execute
3428 //     <-- every thing is still working at this moment -->
3429 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3430 //        shutdown hooks
3431 //   + Call before_exit(), prepare for VM exit
3432 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3433 //        currently the only user of this mechanism is File.deleteOnExit())
3434 //      > stop StatSampler, watcher thread,
3435 //        post thread end and vm death events to JVMTI,
3436 //        stop signal thread
3437 //   + Call JavaThread::exit(), it will:
3438 //      > release JNI handle blocks, remove stack guard pages
3439 //      > remove this thread from Threads list
3440 //     <-- no more Java code from this thread after this point -->
3441 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3442 //     the compiler threads at safepoint
3443 //     <-- do not use anything that could get blocked by Safepoint -->
3444 //   + Disable tracing at JNI/JVM barriers
3445 //   + Set _vm_exited flag for threads that are still running native code
3446 //   + Call exit_globals()
3447 //      > deletes tty
3448 //      > deletes PerfMemory resources
3449 //   + Delete this thread
3450 //   + Return to caller
3451 
3452 void Threads::destroy_vm() {
3453   JavaThread* thread = JavaThread::current();
3454 
3455 #ifdef ASSERT
3456   _vm_complete = false;
3457 #endif
3458   // Wait until we are the last non-daemon thread to execute
3459   {
3460     MonitorLocker nu(Threads_lock);
3461     while (Threads::number_of_non_daemon_threads() > 1)
3462       // This wait should make safepoint checks, wait without a timeout.
3463       nu.wait(0);
3464   }
3465 
3466   EventShutdown e;
3467   if (e.should_commit()) {
3468     e.set_reason("No remaining non-daemon Java threads");
3469     e.commit();
3470   }
3471 
3472   // Hang forever on exit if we are reporting an error.
3473   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
3474     os::infinite_sleep();
3475   }
3476   os::wait_for_keypress_at_exit();
3477 
3478   // run Java level shutdown hooks
3479   thread->invoke_shutdown_hooks();
3480 
3481   before_exit(thread);
3482 
3483   thread->exit(true);
3484 
3485   // We are no longer on the main thread list but could still be in a
3486   // secondary list where another thread may try to interact with us.
3487   // So wait until all such interactions are complete before we bring
3488   // the VM to the termination safepoint. Normally this would be done
3489   // using thread->smr_delete() below where we delete the thread, but
3490   // we can't call that after the termination safepoint is active as
3491   // we will deadlock on the Threads_lock. Once all interactions are
3492   // complete it is safe to directly delete the thread at any time.
3493   ThreadsSMRSupport::wait_until_not_protected(thread);
3494 
3495   // Stop VM thread.
3496   {
3497     // 4945125 The vm thread comes to a safepoint during exit.
3498     // GC vm_operations can get caught at the safepoint, and the
3499     // heap is unparseable if they are caught. Grab the Heap_lock
3500     // to prevent this. The GC vm_operations will not be able to
3501     // queue until after the vm thread is dead. After this point,
3502     // we'll never emerge out of the safepoint before the VM exits.
3503     // Assert that the thread is terminated so that acquiring the
3504     // Heap_lock doesn't cause the terminated thread to participate in
3505     // the safepoint protocol.
3506 
3507     assert(thread->is_terminated(), "must be terminated here");
3508     MutexLocker ml(Heap_lock);
3509 
3510     VMThread::wait_for_vm_thread_exit();
3511     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3512     VMThread::destroy();
3513   }
3514 
3515   // Now, all Java threads are gone except daemon threads. Daemon threads
3516   // running Java code or in VM are stopped by the Safepoint. However,
3517   // daemon threads executing native code are still running.  But they
3518   // will be stopped at native=>Java/VM barriers. Note that we can't
3519   // simply kill or suspend them, as it is inherently deadlock-prone.
3520 
3521   VM_Exit::set_vm_exited();
3522 
3523   // Clean up ideal graph printers after the VMThread has started
3524   // the final safepoint which will block all the Compiler threads.
3525   // Note that this Thread has already logically exited so the
3526   // clean_up() function's use of a JavaThreadIteratorWithHandle
3527   // would be a problem except set_vm_exited() has remembered the
3528   // shutdown thread which is granted a policy exception.
3529 #if defined(COMPILER2) && !defined(PRODUCT)
3530   IdealGraphPrinter::clean_up();
3531 #endif
3532 
3533   notify_vm_shutdown();
3534 
3535   // exit_globals() will delete tty
3536   exit_globals();
3537 
3538   // Deleting the shutdown thread here is safe. See comment on
3539   // wait_until_not_protected() above.
3540   delete thread;
3541 
3542 #if INCLUDE_JVMCI
3543   if (JVMCICounterSize > 0) {
3544     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
3545   }
3546 #endif
3547 
3548   LogConfiguration::finalize();
3549 }
3550 
3551 
3552 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3553   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3554   return is_supported_jni_version(version);
3555 }
3556 
3557 
3558 jboolean Threads::is_supported_jni_version(jint version) {
3559   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3560   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3561   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3562   if (version == JNI_VERSION_1_8) return JNI_TRUE;
3563   if (version == JNI_VERSION_9) return JNI_TRUE;
3564   if (version == JNI_VERSION_10) return JNI_TRUE;
3565   return JNI_FALSE;
3566 }
3567 
3568 
3569 void Threads::add(JavaThread* p, bool force_daemon) {
3570   // The threads lock must be owned at this point
3571   assert(Threads_lock->owned_by_self(), "must have threads lock");
3572 
3573   BarrierSet::barrier_set()->on_thread_attach(p);
3574 
3575   // Once a JavaThread is added to the Threads list, smr_delete() has
3576   // to be used to delete it. Otherwise we can just delete it directly.
3577   p->set_on_thread_list();
3578 
3579   _number_of_threads++;
3580   oop threadObj = p->threadObj();
3581   bool daemon = true;
3582   // Bootstrapping problem: threadObj can be null for initial
3583   // JavaThread (or for threads attached via JNI)
3584   if ((!force_daemon) && !is_daemon((threadObj))) {
3585     _number_of_non_daemon_threads++;
3586     daemon = false;
3587   }
3588 
3589   ThreadService::add_thread(p, daemon);
3590 
3591   // Maintain fast thread list
3592   ThreadsSMRSupport::add_thread(p);
3593 
3594   // Increase the ObjectMonitor ceiling for the new thread.
3595   ObjectSynchronizer::inc_in_use_list_ceiling();
3596 
3597   // Possible GC point.
3598   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
3599 
3600   // Make new thread known to active EscapeBarrier
3601   EscapeBarrier::thread_added(p);
3602 }
3603 
3604 void Threads::remove(JavaThread* p, bool is_daemon) {
3605   // Extra scope needed for Thread_lock, so we can check
3606   // that we do not remove thread without safepoint code notice
3607   { MonitorLocker ml(Threads_lock);
3608 
3609     // BarrierSet state must be destroyed after the last thread transition
3610     // before the thread terminates. Thread transitions result in calls to
3611     // StackWatermarkSet::on_safepoint(), which performs GC processing,
3612     // requiring the GC state to be alive.
3613     BarrierSet::barrier_set()->on_thread_detach(p);
3614 
3615     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
3616 
3617     // Maintain fast thread list
3618     ThreadsSMRSupport::remove_thread(p);
3619 
3620     _number_of_threads--;
3621     if (!is_daemon) {
3622       _number_of_non_daemon_threads--;
3623 
3624       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3625       // on destroy_vm will wake up.
3626       if (number_of_non_daemon_threads() == 1) {
3627         ml.notify_all();
3628       }
3629     }
3630     ThreadService::remove_thread(p, is_daemon);
3631 
3632     // Make sure that safepoint code disregard this thread. This is needed since
3633     // the thread might mess around with locks after this point. This can cause it
3634     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3635     // of this thread since it is removed from the queue.
3636     p->set_terminated(JavaThread::_thread_terminated);
3637 
3638     // Notify threads waiting in EscapeBarriers
3639     EscapeBarrier::thread_removed(p);
3640   } // unlock Threads_lock
3641 
3642   // Reduce the ObjectMonitor ceiling for the exiting thread.
3643   ObjectSynchronizer::dec_in_use_list_ceiling();
3644 
3645   // Since Events::log uses a lock, we grab it outside the Threads_lock
3646   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
3647 }
3648 
3649 // Operations on the Threads list for GC.  These are not explicitly locked,
3650 // but the garbage collector must provide a safe context for them to run.
3651 // In particular, these things should never be called when the Threads_lock
3652 // is held by some other thread. (Note: the Safepoint abstraction also
3653 // uses the Threads_lock to guarantee this property. It also makes sure that
3654 // all threads gets blocked when exiting or starting).
3655 
3656 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3657   ALL_JAVA_THREADS(p) {
3658     p->oops_do(f, cf);
3659   }
3660   VMThread::vm_thread()->oops_do(f, cf);
3661 }
3662 
3663 void Threads::change_thread_claim_token() {
3664   if (++_thread_claim_token == 0) {
3665     // On overflow of the token counter, there is a risk of future
3666     // collisions between a new global token value and a stale token
3667     // for a thread, because not all iterations visit all threads.
3668     // (Though it's pretty much a theoretical concern for non-trivial
3669     // token counter sizes.)  To deal with the possibility, reset all
3670     // the thread tokens to zero on global token overflow.
3671     struct ResetClaims : public ThreadClosure {
3672       virtual void do_thread(Thread* t) {
3673         t->claim_threads_do(false, 0);
3674       }
3675     } reset_claims;
3676     Threads::threads_do(&reset_claims);
3677     // On overflow, update the global token to non-zero, to
3678     // avoid the special "never claimed" initial thread value.
3679     _thread_claim_token = 1;
3680   }
3681 }
3682 
3683 #ifdef ASSERT
3684 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
3685   const uintx token = t->threads_do_token();
3686   assert(token == expected,
3687          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
3688          UINTX_FORMAT, kind, p2i(t), token, expected);
3689 }
3690 
3691 void Threads::assert_all_threads_claimed() {
3692   ALL_JAVA_THREADS(p) {
3693     assert_thread_claimed("Thread", p, _thread_claim_token);
3694   }
3695   assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
3696 }
3697 #endif // ASSERT
3698 
3699 class ParallelOopsDoThreadClosure : public ThreadClosure {
3700 private:
3701   OopClosure* _f;
3702   CodeBlobClosure* _cf;
3703 public:
3704   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
3705   void do_thread(Thread* t) {
3706     t->oops_do(_f, _cf);
3707   }
3708 };
3709 
3710 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
3711   ParallelOopsDoThreadClosure tc(f, cf);
3712   possibly_parallel_threads_do(is_par, &tc);
3713 }
3714 
3715 void Threads::metadata_do(MetadataClosure* f) {
3716   ALL_JAVA_THREADS(p) {
3717     p->metadata_do(f);
3718   }
3719 }
3720 
3721 class ThreadHandlesClosure : public ThreadClosure {
3722   void (*_f)(Metadata*);
3723  public:
3724   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
3725   virtual void do_thread(Thread* thread) {
3726     thread->metadata_handles_do(_f);
3727   }
3728 };
3729 
3730 void Threads::metadata_handles_do(void f(Metadata*)) {
3731   // Only walk the Handles in Thread.
3732   ThreadHandlesClosure handles_closure(f);
3733   threads_do(&handles_closure);
3734 }
3735 
3736 // Get count Java threads that are waiting to enter the specified monitor.
3737 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
3738                                                          int count,
3739                                                          address monitor) {
3740   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3741 
3742   int i = 0;
3743   DO_JAVA_THREADS(t_list, p) {
3744     if (!p->can_call_java()) continue;
3745 
3746     // The first stage of async deflation does not affect any field
3747     // used by this comparison so the ObjectMonitor* is usable here.
3748     address pending = (address)p->current_pending_monitor();
3749     if (pending == monitor) {             // found a match
3750       if (i < count) result->append(p);   // save the first count matches
3751       i++;
3752     }
3753   }
3754 
3755   return result;
3756 }
3757 
3758 
3759 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
3760                                                       address owner) {
3761   assert(LockingMode != LM_LIGHTWEIGHT, "Not with new lightweight locking");
3762   // NULL owner means not locked so we can skip the search
3763   if (owner == NULL) return NULL;
3764 
3765   DO_JAVA_THREADS(t_list, p) {
3766     // first, see if owner is the address of a Java thread
3767     if (owner == (address)p) return p;
3768   }
3769 
3770   // Cannot assert on lack of success here since this function may be
3771   // used by code that is trying to report useful problem information
3772   // like deadlock detection.
3773   if (UseHeavyMonitors) return NULL;
3774 
3775   // If we didn't find a matching Java thread and we didn't force use of
3776   // heavyweight monitors, then the owner is the stack address of the
3777   // Lock Word in the owning Java thread's stack.
3778   //
3779   JavaThread* the_owner = NULL;
3780   DO_JAVA_THREADS(t_list, q) {
3781     if (q->is_lock_owned(owner)) {
3782       the_owner = q;
3783       break;
3784     }
3785   }
3786 
3787   // cannot assert on lack of success here; see above comment
3788   return the_owner;
3789 }
3790 
3791 JavaThread* Threads::owning_thread_from_object(ThreadsList * t_list, oop obj) {
3792   assert(LockingMode == LM_LIGHTWEIGHT, "Only with new lightweight locking");
3793   DO_JAVA_THREADS(t_list, q) {
3794     if (q->lock_stack().contains(obj)) {
3795       return q;
3796     }
3797   }
3798   return NULL;
3799 }
3800 
3801 JavaThread* Threads::owning_thread_from_monitor(ThreadsList* t_list, ObjectMonitor* monitor) {
3802   if (LockingMode == LM_LIGHTWEIGHT) {
3803     if (monitor->is_owner_anonymous()) {
3804       return owning_thread_from_object(t_list, monitor->object());
3805     } else {
3806       Thread* owner = reinterpret_cast<Thread*>(monitor->owner());
3807       assert(owner == NULL || owner->is_Java_thread(), "only JavaThreads own monitors");
3808       return reinterpret_cast<JavaThread*>(owner);
3809     }
3810   } else {
3811     address owner = (address)monitor->owner();
3812     return owning_thread_from_monitor_owner(t_list, owner);
3813   }
3814 }
3815 
3816 class PrintOnClosure : public ThreadClosure {
3817 private:
3818   outputStream* _st;
3819 
3820 public:
3821   PrintOnClosure(outputStream* st) :
3822       _st(st) {}
3823 
3824   virtual void do_thread(Thread* thread) {
3825     if (thread != NULL) {
3826       thread->print_on(_st);
3827       _st->cr();
3828     }
3829   }
3830 };
3831 
3832 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3833 void Threads::print_on(outputStream* st, bool print_stacks,
3834                        bool internal_format, bool print_concurrent_locks,
3835                        bool print_extended_info) {
3836   char buf[32];
3837   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
3838 
3839   st->print_cr("Full thread dump %s (%s %s):",
3840                VM_Version::vm_name(),
3841                VM_Version::vm_release(),
3842                VM_Version::vm_info_string());
3843   st->cr();
3844 
3845 #if INCLUDE_SERVICES
3846   // Dump concurrent locks
3847   ConcurrentLocksDump concurrent_locks;
3848   if (print_concurrent_locks) {
3849     concurrent_locks.dump_at_safepoint();
3850   }
3851 #endif // INCLUDE_SERVICES
3852 
3853   ThreadsSMRSupport::print_info_on(st);
3854   st->cr();
3855 
3856   ALL_JAVA_THREADS(p) {
3857     ResourceMark rm;
3858     p->print_on(st, print_extended_info);
3859     if (print_stacks) {
3860       if (internal_format) {
3861         p->trace_stack();
3862       } else {
3863         p->print_stack_on(st);
3864       }
3865     }
3866     st->cr();
3867 #if INCLUDE_SERVICES
3868     if (print_concurrent_locks) {
3869       concurrent_locks.print_locks_on(p, st);
3870     }
3871 #endif // INCLUDE_SERVICES
3872   }
3873 
3874   PrintOnClosure cl(st);
3875   cl.do_thread(VMThread::vm_thread());
3876   Universe::heap()->gc_threads_do(&cl);
3877   if (StringDedup::is_enabled()) {
3878     StringDedup::threads_do(&cl);
3879   }
3880   cl.do_thread(WatcherThread::watcher_thread());
3881   cl.do_thread(AsyncLogWriter::instance());
3882 
3883   st->flush();
3884 }
3885 
3886 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
3887                              int buflen, bool* found_current) {
3888   if (this_thread != NULL) {
3889     bool is_current = (current == this_thread);
3890     *found_current = *found_current || is_current;
3891     st->print("%s", is_current ? "=>" : "  ");
3892 
3893     st->print(PTR_FORMAT, p2i(this_thread));
3894     st->print(" ");
3895     this_thread->print_on_error(st, buf, buflen);
3896     st->cr();
3897   }
3898 }
3899 
3900 class PrintOnErrorClosure : public ThreadClosure {
3901   outputStream* _st;
3902   Thread* _current;
3903   char* _buf;
3904   int _buflen;
3905   bool* _found_current;
3906  public:
3907   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
3908                       int buflen, bool* found_current) :
3909    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
3910 
3911   virtual void do_thread(Thread* thread) {
3912     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
3913   }
3914 };
3915 
3916 // Threads::print_on_error() is called by fatal error handler. It's possible
3917 // that VM is not at safepoint and/or current thread is inside signal handler.
3918 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3919 // memory (even in resource area), it might deadlock the error handler.
3920 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
3921                              int buflen) {
3922   ThreadsSMRSupport::print_info_on(st);
3923   st->cr();
3924 
3925   bool found_current = false;
3926   st->print_cr("Java Threads: ( => current thread )");
3927   ALL_JAVA_THREADS(thread) {
3928     print_on_error(thread, st, current, buf, buflen, &found_current);
3929   }
3930   st->cr();
3931 
3932   st->print_cr("Other Threads:");
3933   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
3934   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
3935   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
3936 
3937   if (Universe::heap() != NULL) {
3938     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3939     Universe::heap()->gc_threads_do(&print_closure);
3940   }
3941 
3942   if (StringDedup::is_enabled()) {
3943     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3944     StringDedup::threads_do(&print_closure);
3945   }
3946 
3947   if (!found_current) {
3948     st->cr();
3949     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
3950     current->print_on_error(st, buf, buflen);
3951     st->cr();
3952   }
3953   st->cr();
3954 
3955   st->print_cr("Threads with active compile tasks:");
3956   print_threads_compiling(st, buf, buflen);
3957 }
3958 
3959 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
3960   ALL_JAVA_THREADS(thread) {
3961     if (thread->is_Compiler_thread()) {
3962       CompilerThread* ct = (CompilerThread*) thread;
3963 
3964       // Keep task in local variable for NULL check.
3965       // ct->_task might be set to NULL by concurring compiler thread
3966       // because it completed the compilation. The task is never freed,
3967       // though, just returned to a free list.
3968       CompileTask* task = ct->task();
3969       if (task != NULL) {
3970         thread->print_name_on_error(st, buf, buflen);
3971         st->print("  ");
3972         task->print(st, NULL, short_form, true);
3973       }
3974     }
3975   }
3976 }
3977 
3978 
3979 // Ad-hoc mutual exclusion primitives: SpinLock
3980 //
3981 // We employ SpinLocks _only for low-contention, fixed-length
3982 // short-duration critical sections where we're concerned
3983 // about native mutex_t or HotSpot Mutex:: latency.
3984 //
3985 // TODO-FIXME: ListLock should be of type SpinLock.
3986 // We should make this a 1st-class type, integrated into the lock
3987 // hierarchy as leaf-locks.  Critically, the SpinLock structure
3988 // should have sufficient padding to avoid false-sharing and excessive
3989 // cache-coherency traffic.
3990 
3991 
3992 typedef volatile int SpinLockT;
3993 
3994 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
3995   if (Atomic::cmpxchg(adr, 0, 1) == 0) {
3996     return;   // normal fast-path return
3997   }
3998 
3999   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4000   int ctr = 0;
4001   int Yields = 0;
4002   for (;;) {
4003     while (*adr != 0) {
4004       ++ctr;
4005       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4006         if (Yields > 5) {
4007           os::naked_short_sleep(1);
4008         } else {
4009           os::naked_yield();
4010           ++Yields;
4011         }
4012       } else {
4013         SpinPause();
4014       }
4015     }
4016     if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
4017   }
4018 }
4019 
4020 void Thread::SpinRelease(volatile int * adr) {
4021   assert(*adr != 0, "invariant");
4022   OrderAccess::fence();      // guarantee at least release consistency.
4023   // Roach-motel semantics.
4024   // It's safe if subsequent LDs and STs float "up" into the critical section,
4025   // but prior LDs and STs within the critical section can't be allowed
4026   // to reorder or float past the ST that releases the lock.
4027   // Loads and stores in the critical section - which appear in program
4028   // order before the store that releases the lock - must also appear
4029   // before the store that releases the lock in memory visibility order.
4030   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4031   // the ST of 0 into the lock-word which releases the lock, so fence
4032   // more than covers this on all platforms.
4033   *adr = 0;
4034 }
4035 
4036 
4037 void Threads::verify() {
4038   ALL_JAVA_THREADS(p) {
4039     p->verify();
4040   }
4041   VMThread* thread = VMThread::vm_thread();
4042   if (thread != NULL) thread->verify();
4043 }
4044 
4045 #ifndef PRODUCT
4046 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
4047    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
4048 }
4049 #endif
4050 
4051 // Starts the target JavaThread as a daemon of the given priority, and
4052 // bound to the given java.lang.Thread instance.
4053 // The Threads_lock is held for the duration.
4054 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
4055                                        Handle thread_oop, ThreadPriority prio) {
4056 
4057   assert(target->osthread()!= NULL, "target thread is not properly initialized");
4058 
4059   MutexLocker mu(current, Threads_lock);
4060 
4061   // Initialize the fields of the thread_oop first.
4062   if (prio != NoPriority) {
4063     java_lang_Thread::set_priority(thread_oop(), prio);
4064     // Note: we don't call os::set_priority here. Possibly we should,
4065     // else all threads should call it themselves when they first run.
4066   }
4067 
4068   java_lang_Thread::set_daemon(thread_oop());
4069 
4070   // Now bind the thread_oop to the target JavaThread.
4071   target->set_threadObj(thread_oop());
4072 
4073   Threads::add(target); // target is now visible for safepoint/handshake
4074   // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
4075   // on a ThreadsList. We don't want to wait for the release when the
4076   // Theads_lock is dropped when the 'mu' destructor is run since the
4077   // JavaThread* is already visible to JVM/TI via the ThreadsList.
4078   java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
4079   Thread::start(target);
4080 }
4081 
4082 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
4083   // At this point it may be possible that no osthread was created for the
4084   // JavaThread due to lack of resources. However, since this must work
4085   // for critical system threads just check and abort if this fails.
4086   if (thread->osthread() == nullptr) {
4087     // This isn't really an OOM condition, but historically this is what
4088     // we report.
4089     vm_exit_during_initialization("java.lang.OutOfMemoryError",
4090                                   os::native_thread_creation_failed_msg());
4091   }
4092 }
--- EOF ---