1 /*
   2  * Copyright (c) 1997, 2022, 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/fieldDescriptor.inline.hpp"
  80 #include "runtime/flags/jvmFlagLimit.hpp"
  81 #include "runtime/deoptimization.hpp"
  82 #include "runtime/frame.inline.hpp"
  83 #include "runtime/handles.inline.hpp"
  84 #include "runtime/handshake.hpp"
  85 #include "runtime/init.hpp"
  86 #include "runtime/interfaceSupport.inline.hpp"
  87 #include "runtime/java.hpp"
  88 #include "runtime/javaCalls.hpp"
  89 #include "runtime/jniHandles.inline.hpp"
  90 #include "runtime/jniPeriodicChecker.hpp"
  91 #include "runtime/monitorDeflationThread.hpp"
  92 #include "runtime/mutexLocker.hpp"
  93 #include "runtime/nonJavaThread.hpp"
  94 #include "runtime/objectMonitor.hpp"
  95 #include "runtime/orderAccess.hpp"
  96 #include "runtime/osThread.hpp"
  97 #include "runtime/safepoint.hpp"
  98 #include "runtime/safepointMechanism.inline.hpp"
  99 #include "runtime/safepointVerifiers.hpp"
 100 #include "runtime/serviceThread.hpp"
 101 #include "runtime/sharedRuntime.hpp"
 102 #include "runtime/stackFrameStream.inline.hpp"
 103 #include "runtime/stackWatermarkSet.hpp"
 104 #include "runtime/statSampler.hpp"
 105 #include "runtime/task.hpp"
 106 #include "runtime/thread.inline.hpp"
 107 #include "runtime/threadCritical.hpp"
 108 #include "runtime/threadSMR.inline.hpp"
 109 #include "runtime/threadStatisticalInfo.hpp"
 110 #include "runtime/threadWXSetters.inline.hpp"
 111 #include "runtime/timer.hpp"
 112 #include "runtime/timerTrace.hpp"
 113 #include "runtime/vframe.inline.hpp"
 114 #include "runtime/vframeArray.hpp"
 115 #include "runtime/vframe_hp.hpp"
 116 #include "runtime/vmThread.hpp"
 117 #include "runtime/vmOperations.hpp"
 118 #include "runtime/vm_version.hpp"
 119 #include "services/attachListener.hpp"
 120 #include "services/management.hpp"
 121 #include "services/memTracker.hpp"
 122 #include "services/threadService.hpp"
 123 #include "utilities/align.hpp"
 124 #include "utilities/copy.hpp"
 125 #include "utilities/defaultStream.hpp"
 126 #include "utilities/dtrace.hpp"
 127 #include "utilities/events.hpp"
 128 #include "utilities/macros.hpp"
 129 #include "utilities/preserveException.hpp"
 130 #include "utilities/spinYield.hpp"
 131 #include "utilities/vmError.hpp"
 132 #if INCLUDE_JVMCI
 133 #include "jvmci/jvmci.hpp"
 134 #include "jvmci/jvmciEnv.hpp"
 135 #endif
 136 #ifdef COMPILER1
 137 #include "c1/c1_Compiler.hpp"
 138 #endif
 139 #ifdef COMPILER2
 140 #include "opto/c2compiler.hpp"
 141 #include "opto/idealGraphPrinter.hpp"
 142 #endif
 143 #if INCLUDE_RTM_OPT
 144 #include "runtime/rtmLocking.hpp"
 145 #endif
 146 #if INCLUDE_JFR
 147 #include "jfr/jfr.hpp"
 148 #endif
 149 
 150 // Initialization after module runtime initialization
 151 void universe_post_module_init();  // must happen after call_initPhase2
 152 
 153 #ifdef DTRACE_ENABLED
 154 
 155 // Only bother with this argument setup if dtrace is available
 156 
 157   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 158   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 159 
 160   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 161     {                                                                      \
 162       ResourceMark rm(this);                                               \
 163       int len = 0;                                                         \
 164       const char* name = (javathread)->name();                             \
 165       len = strlen(name);                                                  \
 166       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 167         (char *) name, len,                                                \
 168         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 169         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 170         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 171     }
 172 
 173 #else //  ndef DTRACE_ENABLED
 174 
 175   #define DTRACE_THREAD_PROBE(probe, javathread)
 176 
 177 #endif // ndef DTRACE_ENABLED
 178 
 179 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 180 // Current thread is maintained as a thread-local variable
 181 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
 182 #endif
 183 
 184 // ======= Thread ========
 185 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 186   return throw_excpt ? AllocateHeap(size, flags, CURRENT_PC)
 187                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 188 }
 189 
 190 void Thread::operator delete(void* p) {
 191   FreeHeap(p);
 192 }
 193 
 194 void JavaThread::smr_delete() {
 195   if (_on_thread_list) {
 196     ThreadsSMRSupport::smr_delete(this);
 197   } else {
 198     delete this;
 199   }
 200 }
 201 
 202 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 203 // JavaThread
 204 
 205 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
 206 
 207 Thread::Thread() {
 208 
 209   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 210 
 211   // stack and get_thread
 212   set_stack_base(NULL);
 213   set_stack_size(0);
 214   set_lgrp_id(-1);
 215   DEBUG_ONLY(clear_suspendible_thread();)
 216 
 217   // allocated data structures
 218   set_osthread(NULL);
 219   set_resource_area(new (mtThread)ResourceArea());
 220   DEBUG_ONLY(_current_resource_mark = NULL;)
 221   set_handle_area(new (mtThread) HandleArea(NULL));
 222   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
 223   set_last_handle_mark(NULL);
 224   DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
 225 
 226   // Initial value of zero ==> never claimed.
 227   _threads_do_token = 0;
 228   _threads_hazard_ptr = NULL;
 229   _threads_list_ptr = NULL;
 230   _nested_threads_hazard_ptr_cnt = 0;
 231   _rcu_counter = 0;
 232 
 233   // the handle mark links itself to last_handle_mark
 234   new HandleMark(this);
 235 
 236   // plain initialization
 237   debug_only(_owned_locks = NULL;)
 238   NOT_PRODUCT(_skip_gcalot = false;)
 239   _jvmti_env_iteration_count = 0;
 240   set_allocated_bytes(0);
 241   _current_pending_raw_monitor = NULL;
 242 
 243   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 244   _hashStateX = os::random();
 245   _hashStateY = 842502087;
 246   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 247   _hashStateW = 273326509;
 248 
 249   // Many of the following fields are effectively final - immutable
 250   // Note that nascent threads can't use the Native Monitor-Mutex
 251   // construct until the _MutexEvent is initialized ...
 252   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 253   // we might instead use a stack of ParkEvents that we could provision on-demand.
 254   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 255   // and ::Release()
 256   _ParkEvent   = ParkEvent::Allocate(this);
 257 
 258 #ifdef CHECK_UNHANDLED_OOPS
 259   if (CheckUnhandledOops) {
 260     _unhandled_oops = new UnhandledOops(this);
 261   }
 262 #endif // CHECK_UNHANDLED_OOPS
 263 
 264   // Notify the barrier set that a thread is being created. The initial
 265   // thread is created before the barrier set is available.  The call to
 266   // BarrierSet::on_thread_create() for this thread is therefore deferred
 267   // to BarrierSet::set_barrier_set().
 268   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 269   if (barrier_set != NULL) {
 270     barrier_set->on_thread_create(this);
 271   } else {
 272     // Only the main thread should be created before the barrier set
 273     // and that happens just before Thread::current is set. No other thread
 274     // can attach as the VM is not created yet, so they can't execute this code.
 275     // If the main thread creates other threads before the barrier set that is an error.
 276     assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
 277   }
 278 
 279   MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
 280 }
 281 
 282 void Thread::initialize_tlab() {
 283   if (UseTLAB) {
 284     tlab().initialize();
 285   }
 286 }
 287 
 288 void Thread::initialize_thread_current() {
 289 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 290   assert(_thr_current == NULL, "Thread::current already initialized");
 291   _thr_current = this;
 292 #endif
 293   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 294   ThreadLocalStorage::set_thread(this);
 295   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 296 }
 297 
 298 void Thread::clear_thread_current() {
 299   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 300 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 301   _thr_current = NULL;
 302 #endif
 303   ThreadLocalStorage::set_thread(NULL);
 304 }
 305 
 306 void Thread::record_stack_base_and_size() {
 307   // Note: at this point, Thread object is not yet initialized. Do not rely on
 308   // any members being initialized. Do not rely on Thread::current() being set.
 309   // If possible, refrain from doing anything which may crash or assert since
 310   // quite probably those crash dumps will be useless.
 311   set_stack_base(os::current_stack_base());
 312   set_stack_size(os::current_stack_size());
 313 
 314   // Set stack limits after thread is initialized.
 315   if (is_Java_thread()) {
 316     JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
 317   }
 318 }
 319 
 320 void Thread::register_thread_stack_with_NMT() {
 321   MemTracker::record_thread_stack(stack_end(), stack_size());
 322 }
 323 
 324 void Thread::unregister_thread_stack_with_NMT() {
 325   MemTracker::release_thread_stack(stack_end(), stack_size());
 326 }
 327 
 328 void Thread::call_run() {
 329   DEBUG_ONLY(_run_state = CALL_RUN;)
 330 
 331   // At this point, Thread object should be fully initialized and
 332   // Thread::current() should be set.
 333 
 334   assert(Thread::current_or_null() != NULL, "current thread is unset");
 335   assert(Thread::current_or_null() == this, "current thread is wrong");
 336 
 337   // Perform common initialization actions
 338 
 339   MACOS_AARCH64_ONLY(this->init_wx());
 340 
 341   register_thread_stack_with_NMT();
 342 
 343   JFR_ONLY(Jfr::on_thread_start(this);)
 344 
 345   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 346     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 347     os::current_thread_id(), p2i(stack_end()),
 348     p2i(stack_base()), stack_size()/1024);
 349 
 350   // Perform <ChildClass> initialization actions
 351   DEBUG_ONLY(_run_state = PRE_RUN;)
 352   this->pre_run();
 353 
 354   // Invoke <ChildClass>::run()
 355   DEBUG_ONLY(_run_state = RUN;)
 356   this->run();
 357   // Returned from <ChildClass>::run(). Thread finished.
 358 
 359   // Perform common tear-down actions
 360 
 361   assert(Thread::current_or_null() != NULL, "current thread is unset");
 362   assert(Thread::current_or_null() == this, "current thread is wrong");
 363 
 364   // Perform <ChildClass> tear-down actions
 365   DEBUG_ONLY(_run_state = POST_RUN;)
 366   this->post_run();
 367 
 368   // Note: at this point the thread object may already have deleted itself,
 369   // so from here on do not dereference *this*. Not all thread types currently
 370   // delete themselves when they terminate. But no thread should ever be deleted
 371   // asynchronously with respect to its termination - that is what _run_state can
 372   // be used to check.
 373 
 374   assert(Thread::current_or_null() == NULL, "current thread still present");
 375 }
 376 
 377 Thread::~Thread() {
 378 
 379   // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
 380   // get started due to errors etc. Any active thread should at least reach post_run
 381   // before it is deleted (usually in post_run()).
 382   assert(_run_state == PRE_CALL_RUN ||
 383          _run_state == POST_RUN, "Active Thread deleted before post_run(): "
 384          "_run_state=%d", (int)_run_state);
 385 
 386   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 387   // set might not be available if we encountered errors during bootstrapping.
 388   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 389   if (barrier_set != NULL) {
 390     barrier_set->on_thread_destroy(this);
 391   }
 392 
 393   // deallocate data structures
 394   delete resource_area();
 395   // since the handle marks are using the handle area, we have to deallocated the root
 396   // handle mark before deallocating the thread's handle area,
 397   assert(last_handle_mark() != NULL, "check we have an element");
 398   delete last_handle_mark();
 399   assert(last_handle_mark() == NULL, "check we have reached the end");
 400 
 401   ParkEvent::Release(_ParkEvent);
 402   // Set to NULL as a termination indicator for has_terminated().
 403   Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
 404 
 405   delete handle_area();
 406   delete metadata_handles();
 407 
 408   // osthread() can be NULL, if creation of thread failed.
 409   if (osthread() != NULL) os::free_thread(osthread());
 410 
 411   // Clear Thread::current if thread is deleting itself and it has not
 412   // already been done. This must be done before the memory is deallocated.
 413   // Needed to ensure JNI correctly detects non-attached threads.
 414   if (this == Thread::current_or_null()) {
 415     Thread::clear_thread_current();
 416   }
 417 
 418   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 419 }
 420 
 421 #ifdef ASSERT
 422 // A JavaThread is considered dangling if it not handshake-safe with respect to
 423 // the current thread, it is not on a ThreadsList, or not at safepoint.
 424 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 425   assert(!thread->is_Java_thread() ||
 426          JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
 427          !JavaThread::cast(thread)->on_thread_list() ||
 428          SafepointSynchronize::is_at_safepoint() ||
 429          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
 430          "possibility of dangling Thread pointer");
 431 }
 432 #endif
 433 
 434 // Is the target JavaThread protected by the calling Thread or by some other
 435 // mechanism?
 436 //
 437 bool Thread::is_JavaThread_protected(const JavaThread* target) {
 438   Thread* current_thread = Thread::current();
 439 
 440   // Do the simplest check first:
 441   if (SafepointSynchronize::is_at_safepoint()) {
 442     // The target is protected since JavaThreads cannot exit
 443     // while we're at a safepoint.
 444     return true;
 445   }
 446 
 447   // If the target hasn't been started yet then it is trivially
 448   // "protected". We assume the caller is the thread that will do
 449   // the starting.
 450   if (target->osthread() == NULL || target->osthread()->get_state() <= INITIALIZED) {
 451     return true;
 452   }
 453 
 454   // Now make the simple checks based on who the caller is:
 455   if (current_thread == target || Threads_lock->owner() == current_thread) {
 456     // Target JavaThread is self or calling thread owns the Threads_lock.
 457     // Second check is the same as Threads_lock->owner_is_self(),
 458     // but we already have the current thread so check directly.
 459     return true;
 460   }
 461 
 462   // Check the ThreadsLists associated with the calling thread (if any)
 463   // to see if one of them protects the target JavaThread:
 464   if (is_JavaThread_protected_by_TLH(target)) {
 465     return true;
 466   }
 467 
 468   // Use this debug code with -XX:+UseNewCode to diagnose locations that
 469   // are missing a ThreadsListHandle or other protection mechanism:
 470   // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting target="
 471   //           INTPTR_FORMAT, p2i(current_thread), p2i(target));
 472 
 473   // Note: Since 'target' isn't protected by a TLH, the call to
 474   // target->is_handshake_safe_for() may crash, but we have debug bits so
 475   // we'll be able to figure out what protection mechanism is missing.
 476   assert(target->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
 477          " is not protected and not handshake safe.", p2i(target));
 478 
 479   // The target JavaThread is not protected so it is not safe to query:
 480   return false;
 481 }
 482 
 483 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
 484 // with the calling Thread?
 485 //
 486 bool Thread::is_JavaThread_protected_by_TLH(const JavaThread* target) {
 487   Thread* current_thread = Thread::current();
 488 
 489   // Check the ThreadsLists associated with the calling thread (if any)
 490   // to see if one of them protects the target JavaThread:
 491   for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
 492        stlp != NULL; stlp = stlp->previous()) {
 493     if (stlp->list()->includes(target)) {
 494       // The target JavaThread is protected by this ThreadsList:
 495       return true;
 496     }
 497   }
 498 
 499   // The target JavaThread is not protected by a TLH so it is not safe to query:
 500   return false;
 501 }
 502 
 503 ThreadPriority Thread::get_priority(const Thread* const thread) {
 504   ThreadPriority priority;
 505   // Can return an error!
 506   (void)os::get_priority(thread, priority);
 507   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 508   return priority;
 509 }
 510 
 511 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 512   debug_only(check_for_dangling_thread_pointer(thread);)
 513   // Can return an error!
 514   (void)os::set_priority(thread, priority);
 515 }
 516 
 517 
 518 void Thread::start(Thread* thread) {
 519   // Start is different from resume in that its safety is guaranteed by context or
 520   // being called from a Java method synchronized on the Thread object.
 521   if (thread->is_Java_thread()) {
 522     // Initialize the thread state to RUNNABLE before starting this thread.
 523     // Can not set it after the thread started because we do not know the
 524     // exact thread state at that time. It could be in MONITOR_WAIT or
 525     // in SLEEPING or some other state.
 526     java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
 527                                         JavaThreadStatus::RUNNABLE);
 528   }
 529   os::start_thread(thread);
 530 }
 531 
 532 // GC Support
 533 bool Thread::claim_par_threads_do(uintx claim_token) {
 534   uintx token = _threads_do_token;
 535   if (token != claim_token) {
 536     uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
 537     if (res == token) {
 538       return true;
 539     }
 540     guarantee(res == claim_token, "invariant");
 541   }
 542   return false;
 543 }
 544 
 545 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
 546   // Do oop for ThreadShadow
 547   f->do_oop((oop*)&_pending_exception);
 548   handle_area()->oops_do(f);
 549 }
 550 
 551 // If the caller is a NamedThread, then remember, in the current scope,
 552 // the given JavaThread in its _processed_thread field.
 553 class RememberProcessedThread: public StackObj {
 554   NamedThread* _cur_thr;
 555 public:
 556   RememberProcessedThread(Thread* thread) {
 557     Thread* self = Thread::current();
 558     if (self->is_Named_thread()) {
 559       _cur_thr = (NamedThread *)self;
 560       assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
 561       _cur_thr->set_processed_thread(thread);
 562     } else {
 563       _cur_thr = NULL;
 564     }
 565   }
 566 
 567   ~RememberProcessedThread() {
 568     if (_cur_thr) {
 569       assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
 570       _cur_thr->set_processed_thread(NULL);
 571     }
 572   }
 573 };
 574 
 575 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 576   // Record JavaThread to GC thread
 577   RememberProcessedThread rpt(this);
 578   oops_do_no_frames(f, cf);
 579   oops_do_frames(f, cf);
 580 }
 581 
 582 void Thread::metadata_handles_do(void f(Metadata*)) {
 583   // Only walk the Handles in Thread.
 584   if (metadata_handles() != NULL) {
 585     for (int i = 0; i< metadata_handles()->length(); i++) {
 586       f(metadata_handles()->at(i));
 587     }
 588   }
 589 }
 590 
 591 void Thread::print_on(outputStream* st, bool print_extended_info) const {
 592   // get_priority assumes osthread initialized
 593   if (osthread() != NULL) {
 594     int os_prio;
 595     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 596       st->print("os_prio=%d ", os_prio);
 597     }
 598 
 599     st->print("cpu=%.2fms ",
 600               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 601               );
 602     st->print("elapsed=%.2fs ",
 603               _statistical_info.getElapsedTime() / 1000.0
 604               );
 605     if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
 606       size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
 607       st->print("allocated=" SIZE_FORMAT "%s ",
 608                 byte_size_in_proper_unit(allocated_bytes),
 609                 proper_unit_for_byte_size(allocated_bytes)
 610                 );
 611       st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
 612     }
 613 
 614     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 615     osthread()->print_on(st);
 616   }
 617   ThreadsSMRSupport::print_info_on(this, st);
 618   st->print(" ");
 619   debug_only(if (WizardMode) print_owned_locks_on(st);)
 620 }
 621 
 622 void Thread::print() const { print_on(tty); }
 623 
 624 // Thread::print_on_error() is called by fatal error handler. Don't use
 625 // any lock or allocate memory.
 626 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 627   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 628 
 629   st->print("%s \"%s\"", type_name(), name());
 630 
 631   OSThread* os_thr = osthread();
 632   if (os_thr != NULL) {
 633     if (os_thr->get_state() != ZOMBIE) {
 634       st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 635                 p2i(stack_end()), p2i(stack_base()));
 636       st->print(" [id=%d]", osthread()->thread_id());
 637     } else {
 638       st->print(" terminated");
 639     }
 640   } else {
 641     st->print(" unknown state (no osThread)");
 642   }
 643   ThreadsSMRSupport::print_info_on(this, st);
 644 }
 645 
 646 void Thread::print_value_on(outputStream* st) const {
 647   if (is_Named_thread()) {
 648     st->print(" \"%s\" ", name());
 649   }
 650   st->print(INTPTR_FORMAT, p2i(this));   // print address
 651 }
 652 
 653 #ifdef ASSERT
 654 void Thread::print_owned_locks_on(outputStream* st) const {
 655   Mutex* cur = _owned_locks;
 656   if (cur == NULL) {
 657     st->print(" (no locks) ");
 658   } else {
 659     st->print_cr(" Locks owned:");
 660     while (cur) {
 661       cur->print_on(st);
 662       cur = cur->next();
 663     }
 664   }
 665 }
 666 #endif // ASSERT
 667 
 668 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 669 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 670 // used for compilation in the future. If that change is made, the need for these methods
 671 // should be revisited, and they should be removed if possible.
 672 
 673 bool Thread::is_lock_owned(address adr) const {
 674   return is_in_full_stack(adr);
 675 }
 676 
 677 bool Thread::set_as_starting_thread() {
 678   assert(_starting_thread == NULL, "already initialized: "
 679          "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
 680   // NOTE: this must be called inside the main thread.
 681   DEBUG_ONLY(_starting_thread = this;)
 682   return os::create_main_thread(JavaThread::cast(this));
 683 }
 684 
 685 static void initialize_class(Symbol* class_name, TRAPS) {
 686   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 687   InstanceKlass::cast(klass)->initialize(CHECK);
 688 }
 689 
 690 
 691 // Creates the initial ThreadGroup
 692 static Handle create_initial_thread_group(TRAPS) {
 693   Handle system_instance = JavaCalls::construct_new_instance(
 694                             vmClasses::ThreadGroup_klass(),
 695                             vmSymbols::void_method_signature(),
 696                             CHECK_NH);
 697   Universe::set_system_thread_group(system_instance());
 698 
 699   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 700   Handle main_instance = JavaCalls::construct_new_instance(
 701                             vmClasses::ThreadGroup_klass(),
 702                             vmSymbols::threadgroup_string_void_signature(),
 703                             system_instance,
 704                             string,
 705                             CHECK_NH);
 706   return main_instance;
 707 }
 708 
 709 // Creates the initial Thread, and sets it to running.
 710 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 711                                  TRAPS) {
 712   InstanceKlass* ik = vmClasses::Thread_klass();
 713   assert(ik->is_initialized(), "must be");
 714   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 715 
 716   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 717   // constructor calls Thread.current(), which must be set here for the
 718   // initial thread.
 719   java_lang_Thread::set_thread(thread_oop(), thread);
 720   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 721   thread->set_threadObj(thread_oop());
 722 
 723   Handle string = java_lang_String::create_from_str("main", CHECK);
 724 
 725   JavaValue result(T_VOID);
 726   JavaCalls::call_special(&result, thread_oop,
 727                           ik,
 728                           vmSymbols::object_initializer_name(),
 729                           vmSymbols::threadgroup_string_void_signature(),
 730                           thread_group,
 731                           string,
 732                           CHECK);
 733 
 734   // Set thread status to running since main thread has
 735   // been started and running.
 736   java_lang_Thread::set_thread_status(thread_oop(),
 737                                       JavaThreadStatus::RUNNABLE);
 738 }
 739 
 740 // Extract version and vendor specific information from
 741 // java.lang.VersionProps fields.
 742 // Returned char* is allocated in the thread's resource area
 743 // so must be copied for permanency.
 744 static const char* get_java_version_info(InstanceKlass* ik,
 745                                          Symbol* field_name) {
 746   fieldDescriptor fd;
 747   bool found = ik != NULL &&
 748                ik->find_local_field(field_name,
 749                                     vmSymbols::string_signature(), &fd);
 750   if (found) {
 751     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 752     if (name_oop == NULL) {
 753       return NULL;
 754     }
 755     const char* name = java_lang_String::as_utf8_string(name_oop);
 756     return name;
 757   } else {
 758     return NULL;
 759   }
 760 }
 761 
 762 // General purpose hook into Java code, run once when the VM is initialized.
 763 // The Java library method itself may be changed independently from the VM.
 764 static void call_postVMInitHook(TRAPS) {
 765   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 766   if (klass != NULL) {
 767     JavaValue result(T_VOID);
 768     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 769                            vmSymbols::void_method_signature(),
 770                            CHECK);
 771   }
 772 }
 773 
 774 // Initialized by VMThread at vm_global_init
 775 static OopStorage* _thread_oop_storage = NULL;
 776 
 777 oop  JavaThread::threadObj() const    {
 778   return _threadObj.resolve();
 779 }
 780 
 781 void JavaThread::set_threadObj(oop p) {
 782   assert(_thread_oop_storage != NULL, "not yet initialized");
 783   _threadObj = OopHandle(_thread_oop_storage, p);
 784 }
 785 
 786 OopStorage* JavaThread::thread_oop_storage() {
 787   assert(_thread_oop_storage != NULL, "not yet initialized");
 788   return _thread_oop_storage;
 789 }
 790 
 791 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 792                                     bool daemon, TRAPS) {
 793   assert(thread_group.not_null(), "thread group should be specified");
 794   assert(threadObj() == NULL, "should only create Java thread object once");
 795 
 796   InstanceKlass* ik = vmClasses::Thread_klass();
 797   assert(ik->is_initialized(), "must be");
 798   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 799 
 800   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 801   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 802   // constructor calls Thread.current(), which must be set here.
 803   java_lang_Thread::set_thread(thread_oop(), this);
 804   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 805   set_threadObj(thread_oop());
 806 
 807   JavaValue result(T_VOID);
 808   if (thread_name != NULL) {
 809     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 810     // Thread gets assigned specified name and null target
 811     JavaCalls::call_special(&result,
 812                             thread_oop,
 813                             ik,
 814                             vmSymbols::object_initializer_name(),
 815                             vmSymbols::threadgroup_string_void_signature(),
 816                             thread_group,
 817                             name,
 818                             THREAD);
 819   } else {
 820     // Thread gets assigned name "Thread-nnn" and null target
 821     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 822     JavaCalls::call_special(&result,
 823                             thread_oop,
 824                             ik,
 825                             vmSymbols::object_initializer_name(),
 826                             vmSymbols::threadgroup_runnable_void_signature(),
 827                             thread_group,
 828                             Handle(),
 829                             THREAD);
 830   }
 831 
 832 
 833   if (daemon) {
 834     java_lang_Thread::set_daemon(thread_oop());
 835   }
 836 
 837   if (HAS_PENDING_EXCEPTION) {
 838     return;
 839   }
 840 
 841   Klass* group = vmClasses::ThreadGroup_klass();
 842   Handle threadObj(THREAD, this->threadObj());
 843 
 844   JavaCalls::call_special(&result,
 845                           thread_group,
 846                           group,
 847                           vmSymbols::add_method_name(),
 848                           vmSymbols::thread_void_signature(),
 849                           threadObj,          // Arg 1
 850                           THREAD);
 851 }
 852 
 853 // ======= JavaThread ========
 854 
 855 #if INCLUDE_JVMCI
 856 
 857 jlong* JavaThread::_jvmci_old_thread_counters;
 858 
 859 bool jvmci_counters_include(JavaThread* thread) {
 860   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 861 }
 862 
 863 void JavaThread::collect_counters(jlong* array, int length) {
 864   assert(length == JVMCICounterSize, "wrong value");
 865   for (int i = 0; i < length; i++) {
 866     array[i] = _jvmci_old_thread_counters[i];
 867   }
 868   for (JavaThread* tp : ThreadsListHandle()) {
 869     if (jvmci_counters_include(tp)) {
 870       for (int i = 0; i < length; i++) {
 871         array[i] += tp->_jvmci_counters[i];
 872       }
 873     }
 874   }
 875 }
 876 
 877 // Attempt to enlarge the array for per thread counters.
 878 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 879   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 880   if (new_counters == NULL) {
 881     return NULL;
 882   }
 883   if (old_counters == NULL) {
 884     old_counters = new_counters;
 885     memset(old_counters, 0, sizeof(jlong) * new_size);
 886   } else {
 887     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 888       new_counters[i] = old_counters[i];
 889     }
 890     if (new_size > current_size) {
 891       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 892     }
 893     FREE_C_HEAP_ARRAY(jlong, old_counters);
 894   }
 895   return new_counters;
 896 }
 897 
 898 // Attempt to enlarge the array for per thread counters.
 899 bool JavaThread::resize_counters(int current_size, int new_size) {
 900   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 901   if (new_counters == NULL) {
 902     return false;
 903   } else {
 904     _jvmci_counters = new_counters;
 905     return true;
 906   }
 907 }
 908 
 909 class VM_JVMCIResizeCounters : public VM_Operation {
 910  private:
 911   int _new_size;
 912   bool _failed;
 913 
 914  public:
 915   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 916   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 917   bool allow_nested_vm_operations() const        { return true; }
 918   void doit() {
 919     // Resize the old thread counters array
 920     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 921     if (new_counters == NULL) {
 922       _failed = true;
 923       return;
 924     } else {
 925       JavaThread::_jvmci_old_thread_counters = new_counters;
 926     }
 927 
 928     // Now resize each threads array
 929     for (JavaThread* tp : ThreadsListHandle()) {
 930       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 931         _failed = true;
 932         break;
 933       }
 934     }
 935     if (!_failed) {
 936       JVMCICounterSize = _new_size;
 937     }
 938   }
 939 
 940   bool failed() { return _failed; }
 941 };
 942 
 943 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 944   VM_JVMCIResizeCounters op(new_size);
 945   VMThread::execute(&op);
 946   return !op.failed();
 947 }
 948 
 949 #endif // INCLUDE_JVMCI
 950 
 951 #ifdef ASSERT
 952 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 953 void JavaThread::check_possible_safepoint() {
 954   if (_no_safepoint_count > 0) {
 955     print_owned_locks();
 956     assert(false, "Possible safepoint reached by thread that does not allow it");
 957   }
 958 #ifdef CHECK_UNHANDLED_OOPS
 959   // Clear unhandled oops in JavaThreads so we get a crash right away.
 960   clear_unhandled_oops();
 961 #endif // CHECK_UNHANDLED_OOPS
 962 
 963   // Macos/aarch64 should be in the right state for safepoint (e.g.
 964   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 965   // happens in practice, making such issues hard to find and reproduce.
 966 #if defined(__APPLE__) && defined(AARCH64)
 967   if (AssertWXAtThreadSync) {
 968     assert_wx_state(WXWrite);
 969   }
 970 #endif
 971 }
 972 
 973 void JavaThread::check_for_valid_safepoint_state() {
 974   // Check NoSafepointVerifier, which is implied by locks taken that can be
 975   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 976   // are held.
 977   check_possible_safepoint();
 978 
 979   if (thread_state() != _thread_in_vm) {
 980     fatal("LEAF method calling lock?");
 981   }
 982 
 983   if (GCALotAtAllSafepoints) {
 984     // We could enter a safepoint here and thus have a gc
 985     InterfaceSupport::check_gc_alot();
 986   }
 987 }
 988 #endif // ASSERT
 989 
 990 // A JavaThread is a normal Java thread
 991 
 992 JavaThread::JavaThread() :
 993   // Initialize fields
 994 
 995   _on_thread_list(false),
 996   DEBUG_ONLY(_java_call_counter(0) COMMA)
 997   _entry_point(nullptr),
 998   _deopt_mark(nullptr),
 999   _deopt_nmethod(nullptr),
1000   _vframe_array_head(nullptr),
1001   _vframe_array_last(nullptr),
1002   _jvmti_deferred_updates(nullptr),
1003   _callee_target(nullptr),
1004   _vm_result(nullptr),
1005   _vm_result_2(nullptr),
1006 
1007   _current_pending_monitor(NULL),
1008   _current_pending_monitor_is_from_java(true),
1009   _current_waiting_monitor(NULL),
1010   _active_handles(NULL),
1011   _free_handle_block(NULL),
1012   _Stalled(0),
1013 
1014   _monitor_chunks(nullptr),
1015 
1016   _suspend_flags(0),
1017 
1018   _thread_state(_thread_new),
1019   _saved_exception_pc(nullptr),
1020 #ifdef ASSERT
1021   _no_safepoint_count(0),
1022   _visited_for_critical_count(false),
1023 #endif
1024 
1025   _terminated(_not_terminated),
1026   _in_deopt_handler(0),
1027   _doing_unsafe_access(false),
1028   _do_not_unlock_if_synchronized(false),
1029   _jni_attach_state(_not_attaching_via_jni),
1030 #if INCLUDE_JVMCI
1031   _pending_deoptimization(-1),
1032   _pending_monitorenter(false),
1033   _pending_transfer_to_interpreter(false),
1034   _in_retryable_allocation(false),
1035   _pending_failed_speculation(0),
1036   _jvmci{nullptr},
1037   _libjvmci_runtime(nullptr),
1038   _jvmci_counters(nullptr),
1039   _jvmci_reserved0(0),
1040   _jvmci_reserved1(0),
1041   _jvmci_reserved_oop0(nullptr),
1042 #endif // INCLUDE_JVMCI
1043 
1044   _exception_oop(oop()),
1045   _exception_pc(0),
1046   _exception_handler_pc(0),
1047   _is_method_handle_return(0),
1048 
1049   _jni_active_critical(0),
1050   _pending_jni_exception_check_fn(nullptr),
1051   _depth_first_number(0),
1052 
1053   // JVMTI PopFrame support
1054   _popframe_condition(popframe_inactive),
1055   _frames_to_pop_failed_realloc(0),
1056 
1057   _handshake(this),
1058 
1059   _popframe_preserved_args(nullptr),
1060   _popframe_preserved_args_size(0),
1061 
1062   _jvmti_thread_state(nullptr),
1063   _interp_only_mode(0),
1064   _should_post_on_exceptions_flag(JNI_FALSE),
1065   _thread_stat(new ThreadStatistics()),
1066 
1067   _parker(),
1068 
1069   _class_to_be_initialized(nullptr),
1070 
1071   _SleepEvent(ParkEvent::Allocate(this))
1072 {
1073   set_jni_functions(jni_functions());
1074 
1075 #if INCLUDE_JVMCI
1076   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
1077   if (JVMCICounterSize > 0) {
1078     resize_counters(0, (int) JVMCICounterSize);
1079   }
1080 #endif // INCLUDE_JVMCI
1081 
1082   // Setup safepoint state info for this thread
1083   ThreadSafepointState::create(this);
1084 
1085   SafepointMechanism::initialize_header(this);
1086 
1087   set_requires_cross_modify_fence(false);
1088 
1089   pd_initialize();
1090   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1091 }
1092 
1093 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
1094   if (is_attaching_via_jni) {
1095     _jni_attach_state = _attaching_via_jni;
1096   }
1097 }
1098 
1099 
1100 // interrupt support
1101 
1102 void JavaThread::interrupt() {
1103   // All callers should have 'this' thread protected by a
1104   // ThreadsListHandle so that it cannot terminate and deallocate
1105   // itself.
1106   debug_only(check_for_dangling_thread_pointer(this);)
1107 
1108   // For Windows _interrupt_event
1109   WINDOWS_ONLY(osthread()->set_interrupted(true);)
1110 
1111   // For Thread.sleep
1112   _SleepEvent->unpark();
1113 
1114   // For JSR166 LockSupport.park
1115   parker()->unpark();
1116 
1117   // For ObjectMonitor and JvmtiRawMonitor
1118   _ParkEvent->unpark();
1119 }
1120 
1121 
1122 bool JavaThread::is_interrupted(bool clear_interrupted) {
1123   debug_only(check_for_dangling_thread_pointer(this);)
1124 
1125   if (_threadObj.peek() == NULL) {
1126     // If there is no j.l.Thread then it is impossible to have
1127     // been interrupted. We can find NULL during VM initialization
1128     // or when a JNI thread is still in the process of attaching.
1129     // In such cases this must be the current thread.
1130     assert(this == Thread::current(), "invariant");
1131     return false;
1132   }
1133 
1134   bool interrupted = java_lang_Thread::interrupted(threadObj());
1135 
1136   // NOTE that since there is no "lock" around the interrupt and
1137   // is_interrupted operations, there is the possibility that the
1138   // interrupted flag will be "false" but that the
1139   // low-level events will be in the signaled state. This is
1140   // intentional. The effect of this is that Object.wait() and
1141   // LockSupport.park() will appear to have a spurious wakeup, which
1142   // is allowed and not harmful, and the possibility is so rare that
1143   // it is not worth the added complexity to add yet another lock.
1144   // For the sleep event an explicit reset is performed on entry
1145   // to JavaThread::sleep, so there is no early return. It has also been
1146   // recommended not to put the interrupted flag into the "event"
1147   // structure because it hides the issue.
1148   // Also, because there is no lock, we must only clear the interrupt
1149   // state if we are going to report that we were interrupted; otherwise
1150   // an interrupt that happens just after we read the field would be lost.
1151   if (interrupted && clear_interrupted) {
1152     assert(this == Thread::current(), "only the current thread can clear");
1153     java_lang_Thread::set_interrupted(threadObj(), false);
1154     WINDOWS_ONLY(osthread()->set_interrupted(false);)
1155   }
1156 
1157   return interrupted;
1158 }
1159 
1160 void JavaThread::block_if_vm_exited() {
1161   if (_terminated == _vm_exited) {
1162     // _vm_exited is set at safepoint, and Threads_lock is never released
1163     // we will block here forever.
1164     // Here we can be doing a jump from a safe state to an unsafe state without
1165     // proper transition, but it happens after the final safepoint has begun.
1166     set_thread_state(_thread_in_vm);
1167     Threads_lock->lock();
1168     ShouldNotReachHere();
1169   }
1170 }
1171 
1172 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
1173   _jni_attach_state = _not_attaching_via_jni;
1174   set_entry_point(entry_point);
1175   // Create the native thread itself.
1176   // %note runtime_23
1177   os::ThreadType thr_type = os::java_thread;
1178   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
1179                                                             os::java_thread;
1180   os::create_thread(this, thr_type, stack_sz);
1181   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1182   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1183   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1184   // the exception consists of creating the exception object & initializing it, initialization
1185   // will leave the VM via a JavaCall and then all locks must be unlocked).
1186   //
1187   // The thread is still suspended when we reach here. Thread must be explicit started
1188   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1189   // by calling Threads:add. The reason why this is not done here, is because the thread
1190   // object must be fully initialized (take a look at JVM_Start)
1191 }
1192 
1193 JavaThread::~JavaThread() {
1194 
1195   // Ask ServiceThread to release the threadObj OopHandle
1196   ServiceThread::add_oop_handle_release(_threadObj);
1197 
1198   // Return the sleep event to the free list
1199   ParkEvent::Release(_SleepEvent);
1200   _SleepEvent = NULL;
1201 
1202   // Free any remaining  previous UnrollBlock
1203   vframeArray* old_array = vframe_array_last();
1204 
1205   if (old_array != NULL) {
1206     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1207     old_array->set_unroll_block(NULL);
1208     delete old_info;
1209     delete old_array;
1210   }
1211 
1212   JvmtiDeferredUpdates* updates = deferred_updates();
1213   if (updates != NULL) {
1214     // This can only happen if thread is destroyed before deoptimization occurs.
1215     assert(updates->count() > 0, "Updates holder not deleted");
1216     // free deferred updates.
1217     delete updates;
1218     set_deferred_updates(NULL);
1219   }
1220 
1221   // All Java related clean up happens in exit
1222   ThreadSafepointState::destroy(this);
1223   if (_thread_stat != NULL) delete _thread_stat;
1224 
1225 #if INCLUDE_JVMCI
1226   if (JVMCICounterSize > 0) {
1227     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1228   }
1229 #endif // INCLUDE_JVMCI
1230 }
1231 
1232 
1233 // First JavaThread specific code executed by a new Java thread.
1234 void JavaThread::pre_run() {
1235   // empty - see comments in run()
1236 }
1237 
1238 // The main routine called by a new Java thread. This isn't overridden
1239 // by subclasses, instead different subclasses define a different "entry_point"
1240 // which defines the actual logic for that kind of thread.
1241 void JavaThread::run() {
1242   // initialize thread-local alloc buffer related fields
1243   initialize_tlab();
1244 
1245   _stack_overflow_state.create_stack_guard_pages();
1246 
1247   cache_global_variables();
1248 
1249   // Thread is now sufficiently initialized to be handled by the safepoint code as being
1250   // in the VM. Change thread state from _thread_new to _thread_in_vm
1251   assert(this->thread_state() == _thread_new, "wrong thread state");
1252   set_thread_state(_thread_in_vm);
1253 
1254   // Before a thread is on the threads list it is always safe, so after leaving the
1255   // _thread_new we should emit a instruction barrier. The distance to modified code
1256   // from here is probably far enough, but this is consistent and safe.
1257   OrderAccess::cross_modify_fence();
1258 
1259   assert(JavaThread::current() == this, "sanity check");
1260   assert(!Thread::current()->owns_locks(), "sanity check");
1261 
1262   DTRACE_THREAD_PROBE(start, this);
1263 
1264   // This operation might block. We call that after all safepoint checks for a new thread has
1265   // been completed.
1266   set_active_handles(JNIHandleBlock::allocate_block());
1267 
1268   if (JvmtiExport::should_post_thread_life()) {
1269     JvmtiExport::post_thread_start(this);
1270 
1271   }
1272 
1273   // We call another function to do the rest so we are sure that the stack addresses used
1274   // from there will be lower than the stack base just computed.
1275   thread_main_inner();
1276 }
1277 
1278 void JavaThread::thread_main_inner() {
1279   assert(JavaThread::current() == this, "sanity check");
1280   assert(_threadObj.peek() != NULL, "just checking");
1281 
1282   // Execute thread entry point unless this thread has a pending exception
1283   // or has been stopped before starting.
1284   // Note: Due to JVM_StopThread we can have pending exceptions already!
1285   if (!this->has_pending_exception() &&
1286       !java_lang_Thread::is_stillborn(this->threadObj())) {
1287     {
1288       ResourceMark rm(this);
1289       this->set_native_thread_name(this->name());
1290     }
1291     HandleMark hm(this);
1292     this->entry_point()(this, this);
1293   }
1294 
1295   DTRACE_THREAD_PROBE(stop, this);
1296 
1297   // Cleanup is handled in post_run()
1298 }
1299 
1300 // Shared teardown for all JavaThreads
1301 void JavaThread::post_run() {
1302   this->exit(false);
1303   this->unregister_thread_stack_with_NMT();
1304   // Defer deletion to here to ensure 'this' is still referenceable in call_run
1305   // for any shared tear-down.
1306   this->smr_delete();
1307 }
1308 
1309 static void ensure_join(JavaThread* thread) {
1310   // We do not need to grab the Threads_lock, since we are operating on ourself.
1311   Handle threadObj(thread, thread->threadObj());
1312   assert(threadObj.not_null(), "java thread object must exist");
1313   ObjectLocker lock(threadObj, thread);
1314   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1315   thread->clear_pending_exception();
1316   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1317   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
1318   // Clear the native thread instance - this makes isAlive return false and allows the join()
1319   // to complete once we've done the notify_all below
1320   java_lang_Thread::set_thread(threadObj(), NULL);
1321   lock.notify_all(thread);
1322   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1323   thread->clear_pending_exception();
1324 }
1325 
1326 static bool is_daemon(oop threadObj) {
1327   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1328 }
1329 
1330 // For any new cleanup additions, please check to see if they need to be applied to
1331 // cleanup_failed_attach_current_thread as well.
1332 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1333   assert(this == JavaThread::current(), "thread consistency check");
1334 
1335   elapsedTimer _timer_exit_phase1;
1336   elapsedTimer _timer_exit_phase2;
1337   elapsedTimer _timer_exit_phase3;
1338   elapsedTimer _timer_exit_phase4;
1339 
1340   if (log_is_enabled(Debug, os, thread, timer)) {
1341     _timer_exit_phase1.start();
1342   }
1343 
1344   HandleMark hm(this);
1345   Handle uncaught_exception(this, this->pending_exception());
1346   this->clear_pending_exception();
1347   Handle threadObj(this, this->threadObj());
1348   assert(threadObj.not_null(), "Java thread object should be created");
1349 
1350   if (!destroy_vm) {
1351     if (uncaught_exception.not_null()) {
1352       EXCEPTION_MARK;
1353       // Call method Thread.dispatchUncaughtException().
1354       Klass* thread_klass = vmClasses::Thread_klass();
1355       JavaValue result(T_VOID);
1356       JavaCalls::call_virtual(&result,
1357                               threadObj, thread_klass,
1358                               vmSymbols::dispatchUncaughtException_name(),
1359                               vmSymbols::throwable_void_signature(),
1360                               uncaught_exception,
1361                               THREAD);
1362       if (HAS_PENDING_EXCEPTION) {
1363         ResourceMark rm(this);
1364         jio_fprintf(defaultStream::error_stream(),
1365                     "\nException: %s thrown from the UncaughtExceptionHandler"
1366                     " in thread \"%s\"\n",
1367                     pending_exception()->klass()->external_name(),
1368                     name());
1369         CLEAR_PENDING_EXCEPTION;
1370       }
1371     }
1372 
1373     if (!is_Compiler_thread()) {
1374       // We have finished executing user-defined Java code and now have to do the
1375       // implementation specific clean-up by calling Thread.exit(). We prevent any
1376       // asynchronous exceptions from being delivered while in Thread.exit()
1377       // to ensure the clean-up is not corrupted.
1378       NoAsyncExceptionDeliveryMark _no_async(this);
1379 
1380       EXCEPTION_MARK;
1381       JavaValue result(T_VOID);
1382       Klass* thread_klass = vmClasses::Thread_klass();
1383       JavaCalls::call_virtual(&result,
1384                               threadObj, thread_klass,
1385                               vmSymbols::exit_method_name(),
1386                               vmSymbols::void_method_signature(),
1387                               THREAD);
1388       CLEAR_PENDING_EXCEPTION;
1389     }
1390 
1391     // notify JVMTI
1392     if (JvmtiExport::should_post_thread_life()) {
1393       JvmtiExport::post_thread_end(this);
1394     }
1395 
1396     // The careful dance between thread suspension and exit is handled here.
1397     // Since we are in thread_in_vm state and suspension is done with handshakes,
1398     // we can just put in the exiting state and it will be correctly handled.
1399     set_terminated(_thread_exiting);
1400 
1401     ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1402   } else {
1403     assert(!is_terminated() && !is_exiting(), "must not be exiting");
1404     // before_exit() has already posted JVMTI THREAD_END events
1405   }
1406 
1407   if (log_is_enabled(Debug, os, thread, timer)) {
1408     _timer_exit_phase1.stop();
1409     _timer_exit_phase2.start();
1410   }
1411 
1412   // Capture daemon status before the thread is marked as terminated.
1413   bool daemon = is_daemon(threadObj());
1414 
1415   // Notify waiters on thread object. This has to be done after exit() is called
1416   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1417   // group should have the destroyed bit set before waiters are notified).
1418   ensure_join(this);
1419   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1420 
1421   if (log_is_enabled(Debug, os, thread, timer)) {
1422     _timer_exit_phase2.stop();
1423     _timer_exit_phase3.start();
1424   }
1425   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1426   // held by this thread must be released. The spec does not distinguish
1427   // between JNI-acquired and regular Java monitors. We can only see
1428   // regular Java monitors here if monitor enter-exit matching is broken.
1429   //
1430   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1431   // ObjectSynchronizer::release_monitors_owned_by_thread().
1432   if (exit_type == jni_detach) {
1433     // Sanity check even though JNI DetachCurrentThread() would have
1434     // returned JNI_ERR if there was a Java frame. JavaThread exit
1435     // should be done executing Java code by the time we get here.
1436     assert(!this->has_last_Java_frame(),
1437            "should not have a Java frame when detaching or exiting");
1438     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1439     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1440   }
1441 
1442   // These things needs to be done while we are still a Java Thread. Make sure that thread
1443   // is in a consistent state, in case GC happens
1444   JFR_ONLY(Jfr::on_thread_exit(this);)
1445 
1446   if (active_handles() != NULL) {
1447     JNIHandleBlock* block = active_handles();
1448     set_active_handles(NULL);
1449     JNIHandleBlock::release_block(block);
1450   }
1451 
1452   if (free_handle_block() != NULL) {
1453     JNIHandleBlock* block = free_handle_block();
1454     set_free_handle_block(NULL);
1455     JNIHandleBlock::release_block(block);
1456   }
1457 
1458   // These have to be removed while this is still a valid thread.
1459   _stack_overflow_state.remove_stack_guard_pages();
1460 
1461   if (UseTLAB) {
1462     tlab().retire();
1463   }
1464 
1465   if (JvmtiEnv::environments_might_exist()) {
1466     JvmtiExport::cleanup_thread(this);
1467   }
1468 
1469   // We need to cache the thread name for logging purposes below as once
1470   // we have called on_thread_detach this thread must not access any oops.
1471   char* thread_name = NULL;
1472   if (log_is_enabled(Debug, os, thread, timer)) {
1473     ResourceMark rm(this);
1474     thread_name = os::strdup(name());
1475   }
1476 
1477   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1478     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1479     os::current_thread_id());
1480 
1481   if (log_is_enabled(Debug, os, thread, timer)) {
1482     _timer_exit_phase3.stop();
1483     _timer_exit_phase4.start();
1484   }
1485 
1486 #if INCLUDE_JVMCI
1487   if (JVMCICounterSize > 0) {
1488     if (jvmci_counters_include(this)) {
1489       for (int i = 0; i < JVMCICounterSize; i++) {
1490         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1491       }
1492     }
1493   }
1494 #endif // INCLUDE_JVMCI
1495 
1496   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1497   Threads::remove(this, daemon);
1498 
1499   if (log_is_enabled(Debug, os, thread, timer)) {
1500     _timer_exit_phase4.stop();
1501     log_debug(os, thread, timer)("name='%s'"
1502                                  ", exit-phase1=" JLONG_FORMAT
1503                                  ", exit-phase2=" JLONG_FORMAT
1504                                  ", exit-phase3=" JLONG_FORMAT
1505                                  ", exit-phase4=" JLONG_FORMAT,
1506                                  thread_name,
1507                                  _timer_exit_phase1.milliseconds(),
1508                                  _timer_exit_phase2.milliseconds(),
1509                                  _timer_exit_phase3.milliseconds(),
1510                                  _timer_exit_phase4.milliseconds());
1511     os::free(thread_name);
1512   }
1513 }
1514 
1515 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1516   if (active_handles() != NULL) {
1517     JNIHandleBlock* block = active_handles();
1518     set_active_handles(NULL);
1519     JNIHandleBlock::release_block(block);
1520   }
1521 
1522   if (free_handle_block() != NULL) {
1523     JNIHandleBlock* block = free_handle_block();
1524     set_free_handle_block(NULL);
1525     JNIHandleBlock::release_block(block);
1526   }
1527 
1528   // These have to be removed while this is still a valid thread.
1529   _stack_overflow_state.remove_stack_guard_pages();
1530 
1531   if (UseTLAB) {
1532     tlab().retire();
1533   }
1534 
1535   Threads::remove(this, is_daemon);
1536   this->smr_delete();
1537 }
1538 
1539 JavaThread* JavaThread::active() {
1540   Thread* thread = Thread::current();
1541   if (thread->is_Java_thread()) {
1542     return JavaThread::cast(thread);
1543   } else {
1544     assert(thread->is_VM_thread(), "this must be a vm thread");
1545     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1546     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
1547     return ret;
1548   }
1549 }
1550 
1551 bool JavaThread::is_lock_owned(address adr) const {
1552   if (Thread::is_lock_owned(adr)) return true;
1553 
1554   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1555     if (chunk->contains(adr)) return true;
1556   }
1557 
1558   return false;
1559 }
1560 
1561 oop JavaThread::exception_oop() const {
1562   return Atomic::load(&_exception_oop);
1563 }
1564 
1565 void JavaThread::set_exception_oop(oop o) {
1566   Atomic::store(&_exception_oop, o);
1567 }
1568 
1569 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1570   chunk->set_next(monitor_chunks());
1571   set_monitor_chunks(chunk);
1572 }
1573 
1574 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1575   guarantee(monitor_chunks() != NULL, "must be non empty");
1576   if (monitor_chunks() == chunk) {
1577     set_monitor_chunks(chunk->next());
1578   } else {
1579     MonitorChunk* prev = monitor_chunks();
1580     while (prev->next() != chunk) prev = prev->next();
1581     prev->set_next(chunk->next());
1582   }
1583 }
1584 
1585 void JavaThread::handle_special_runtime_exit_condition() {
1586   if (is_obj_deopt_suspend()) {
1587     frame_anchor()->make_walkable(this);
1588     wait_for_object_deoptimization();
1589   }
1590   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1591 }
1592 
1593 
1594 // Asynchronous exceptions support
1595 //
1596 void JavaThread::handle_async_exception(oop java_throwable) {
1597   assert(java_throwable != NULL, "should have an _async_exception to throw");
1598   assert(!is_at_poll_safepoint(), "should have never called this method");
1599 
1600   if (has_last_Java_frame()) {
1601     frame f = last_frame();
1602     if (f.is_runtime_frame()) {
1603       // If the topmost frame is a runtime stub, then we are calling into
1604       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1605       // must deoptimize the caller before continuing, as the compiled exception
1606       // handler table may not be valid.
1607       RegisterMap reg_map(this, false);
1608       frame compiled_frame = f.sender(&reg_map);
1609       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1610         Deoptimization::deoptimize(this, compiled_frame);
1611       }
1612     }
1613   }
1614 
1615   // Only overwrite an already pending exception if it is not a ThreadDeath.
1616   if (!has_pending_exception() || !pending_exception()->is_a(vmClasses::ThreadDeath_klass())) {
1617 
1618     // We cannot call Exceptions::_throw(...) here because we cannot block
1619     set_pending_exception(java_throwable, __FILE__, __LINE__);
1620 
1621     LogTarget(Info, exceptions) lt;
1622     if (lt.is_enabled()) {
1623       ResourceMark rm;
1624       LogStream ls(lt);
1625       ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1626       if (has_last_Java_frame()) {
1627         frame f = last_frame();
1628         ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1629       }
1630       ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1631     }
1632   }
1633 }
1634 
1635 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1636   // Do not throw asynchronous exceptions against the compiler thread.
1637   if (!can_call_java()) {
1638     delete aeh;
1639     return;
1640   }
1641 
1642   // Don't install a new pending async exception if there is already
1643   // a pending ThreadDeath one. Just interrupt thread from potential
1644   // wait()/sleep()/park() and return.
1645   if (has_async_exception_condition(true /* ThreadDeath_only */)) {
1646     java_lang_Thread::set_interrupted(threadObj(), true);
1647     this->interrupt();
1648     delete aeh;
1649     return;
1650   }
1651 
1652   oop exception = aeh->exception();
1653   Handshake::execute(aeh, this);  // Install asynchronous handshake
1654 
1655   ResourceMark rm;
1656   if (log_is_enabled(Info, exceptions)) {
1657     log_info(exceptions)("Pending Async. exception installed of type: %s",
1658                          InstanceKlass::cast(exception->klass())->external_name());
1659   }
1660   // for AbortVMOnException flag
1661   Exceptions::debug_check_abort(exception->klass()->external_name());
1662 
1663   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1664   java_lang_Thread::set_interrupted(threadObj(), true);
1665   this->interrupt();
1666 }
1667 
1668 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1669   AsyncExceptionHandshake* _aeh;
1670 public:
1671   InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1672     HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1673   void do_thread(Thread* thr) {
1674     JavaThread* target = JavaThread::cast(thr);
1675     target->install_async_exception(_aeh);
1676   }
1677 };
1678 
1679 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1680   OopHandle e(Universe::vm_global(), java_throwable);
1681   InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1682   Handshake::execute(&iaeh, target);
1683 }
1684 
1685 
1686 // External suspension mechanism.
1687 //
1688 // Guarantees on return (for a valid target thread):
1689 //   - Target thread will not execute any new bytecode.
1690 //   - Target thread will not enter any new monitors.
1691 //
1692 bool JavaThread::java_suspend() {
1693   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1694             "missing ThreadsListHandle in calling context.");
1695   return this->handshake_state()->suspend();
1696 }
1697 
1698 bool JavaThread::java_resume() {
1699   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1700             "missing ThreadsListHandle in calling context.");
1701   return this->handshake_state()->resume();
1702 }
1703 
1704 // Wait for another thread to perform object reallocation and relocking on behalf of
1705 // this thread. The current thread is required to change to _thread_blocked in order
1706 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1707 // handshake safe, the other thread can complete the handshake used to synchronize
1708 // with this thread and then perform the reallocation and relocking.
1709 // See EscapeBarrier::sync_and_suspend_*()
1710 
1711 void JavaThread::wait_for_object_deoptimization() {
1712   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1713   assert(this == Thread::current(), "invariant");
1714 
1715   bool spin_wait = os::is_MP();
1716   do {
1717     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1718     // Wait for object deoptimization if requested.
1719     if (spin_wait) {
1720       // A single deoptimization is typically very short. Microbenchmarks
1721       // showed 5% better performance when spinning.
1722       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1723       SpinYield spin(spin_limit);
1724       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1725         spin.wait();
1726       }
1727       // Spin just once
1728       spin_wait = false;
1729     } else {
1730       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1731       if (is_obj_deopt_suspend()) {
1732         ml.wait();
1733       }
1734     }
1735     // A handshake for obj. deoptimization suspend could have been processed so
1736     // we must check after processing.
1737   } while (is_obj_deopt_suspend());
1738 }
1739 
1740 #ifdef ASSERT
1741 // Verify the JavaThread has not yet been published in the Threads::list, and
1742 // hence doesn't need protection from concurrent access at this stage.
1743 void JavaThread::verify_not_published() {
1744   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1745   // since an unpublished JavaThread doesn't participate in the
1746   // Thread-SMR protocol for keeping a ThreadsList alive.
1747   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1748 }
1749 #endif
1750 
1751 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1752 // pending, when _suspend_flags is non-zero or when we need to process a stack
1753 // watermark. Also check for pending async exceptions (except unsafe access error).
1754 // Note only the native==>Java barriers can call this function when thread state
1755 // is _thread_in_native_trans.
1756 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1757   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1758   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1759 
1760   thread->set_thread_state(_thread_in_vm);
1761 
1762   // Enable WXWrite: called directly from interpreter native wrapper.
1763   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1764 
1765   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1766 
1767   // After returning from native, it could be that the stack frames are not
1768   // yet safe to use. We catch such situations in the subsequent stack watermark
1769   // barrier, which will trap unsafe stack frames.
1770   StackWatermarkSet::before_unwind(thread);
1771 }
1772 
1773 #ifndef PRODUCT
1774 // Deoptimization
1775 // Function for testing deoptimization
1776 void JavaThread::deoptimize() {
1777   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1778   bool deopt = false;           // Dump stack only if a deopt actually happens.
1779   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1780   // Iterate over all frames in the thread and deoptimize
1781   for (; !fst.is_done(); fst.next()) {
1782     if (fst.current()->can_be_deoptimized()) {
1783 
1784       if (only_at) {
1785         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1786         // consists of comma or carriage return separated numbers so
1787         // search for the current bci in that string.
1788         address pc = fst.current()->pc();
1789         nmethod* nm =  (nmethod*) fst.current()->cb();
1790         ScopeDesc* sd = nm->scope_desc_at(pc);
1791         char buffer[8];
1792         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1793         size_t len = strlen(buffer);
1794         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1795         while (found != NULL) {
1796           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1797               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1798             // Check that the bci found is bracketed by terminators.
1799             break;
1800           }
1801           found = strstr(found + 1, buffer);
1802         }
1803         if (!found) {
1804           continue;
1805         }
1806       }
1807 
1808       if (DebugDeoptimization && !deopt) {
1809         deopt = true; // One-time only print before deopt
1810         tty->print_cr("[BEFORE Deoptimization]");
1811         trace_frames();
1812         trace_stack();
1813       }
1814       Deoptimization::deoptimize(this, *fst.current());
1815     }
1816   }
1817 
1818   if (DebugDeoptimization && deopt) {
1819     tty->print_cr("[AFTER Deoptimization]");
1820     trace_frames();
1821   }
1822 }
1823 
1824 
1825 // Make zombies
1826 void JavaThread::make_zombies() {
1827   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1828     if (fst.current()->can_be_deoptimized()) {
1829       // it is a Java nmethod
1830       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1831       nm->make_not_entrant();
1832     }
1833   }
1834 }
1835 #endif // PRODUCT
1836 
1837 
1838 void JavaThread::deoptimize_marked_methods() {
1839   if (!has_last_Java_frame()) return;
1840   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1841   for (; !fst.is_done(); fst.next()) {
1842     if (fst.current()->should_be_deoptimized()) {
1843       Deoptimization::deoptimize(this, *fst.current());
1844     }
1845   }
1846 }
1847 
1848 #ifdef ASSERT
1849 void JavaThread::verify_frame_info() {
1850   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1851          (has_last_Java_frame() && java_call_counter() > 0),
1852          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1853          has_last_Java_frame() ? "true" : "false", java_call_counter());
1854 }
1855 #endif
1856 
1857 // Push on a new block of JNI handles.
1858 void JavaThread::push_jni_handle_block() {
1859   // Allocate a new block for JNI handles.
1860   // Inlined code from jni_PushLocalFrame()
1861   JNIHandleBlock* old_handles = active_handles();
1862   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1863   assert(old_handles != NULL && new_handles != NULL, "should not be NULL");
1864   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1865   set_active_handles(new_handles);
1866 }
1867 
1868 // Pop off the current block of JNI handles.
1869 void JavaThread::pop_jni_handle_block() {
1870   // Release our JNI handle block
1871   JNIHandleBlock* old_handles = active_handles();
1872   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1873   assert(new_handles != nullptr, "should never set active handles to null");
1874   set_active_handles(new_handles);
1875   old_handles->set_pop_frame_link(NULL);
1876   JNIHandleBlock::release_block(old_handles, this);
1877 }
1878 
1879 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1880   // Verify that the deferred card marks have been flushed.
1881   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1882 
1883   // Traverse the GCHandles
1884   Thread::oops_do_no_frames(f, cf);
1885 
1886   if (active_handles() != NULL) {
1887     active_handles()->oops_do(f);
1888   }
1889 
1890   DEBUG_ONLY(verify_frame_info();)
1891 
1892   if (has_last_Java_frame()) {
1893     // Traverse the monitor chunks
1894     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1895       chunk->oops_do(f);
1896     }
1897   }
1898 
1899   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1900   // If we have deferred set_locals there might be oops waiting to be
1901   // written
1902   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1903   if (list != NULL) {
1904     for (int i = 0; i < list->length(); i++) {
1905       list->at(i)->oops_do(f);
1906     }
1907   }
1908 
1909   // Traverse instance variables at the end since the GC may be moving things
1910   // around using this function
1911   f->do_oop((oop*) &_vm_result);
1912   f->do_oop((oop*) &_exception_oop);
1913 #if INCLUDE_JVMCI
1914   f->do_oop((oop*) &_jvmci_reserved_oop0);
1915 #endif
1916 
1917   if (jvmti_thread_state() != NULL) {
1918     jvmti_thread_state()->oops_do(f, cf);
1919   }
1920 }
1921 
1922 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1923   if (!has_last_Java_frame()) {
1924     return;
1925   }
1926   // Finish any pending lazy GC activity for the frames
1927   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1928   // Traverse the execution stack
1929   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1930     fst.current()->oops_do(f, cf, fst.register_map());
1931   }
1932 }
1933 
1934 #ifdef ASSERT
1935 void JavaThread::verify_states_for_handshake() {
1936   // This checks that the thread has a correct frame state during a handshake.
1937   verify_frame_info();
1938 }
1939 #endif
1940 
1941 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1942   DEBUG_ONLY(verify_frame_info();)
1943 
1944   if (has_last_Java_frame()) {
1945     // Traverse the execution stack
1946     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1947       fst.current()->nmethods_do(cf);
1948     }
1949   }
1950 
1951   if (jvmti_thread_state() != NULL) {
1952     jvmti_thread_state()->nmethods_do(cf);
1953   }
1954 }
1955 
1956 void JavaThread::metadata_do(MetadataClosure* f) {
1957   if (has_last_Java_frame()) {
1958     // Traverse the execution stack to call f() on the methods in the stack
1959     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1960       fst.current()->metadata_do(f);
1961     }
1962   } else if (is_Compiler_thread()) {
1963     // need to walk ciMetadata in current compile tasks to keep alive.
1964     CompilerThread* ct = (CompilerThread*)this;
1965     if (ct->env() != NULL) {
1966       ct->env()->metadata_do(f);
1967     }
1968     CompileTask* task = ct->task();
1969     if (task != NULL) {
1970       task->metadata_do(f);
1971     }
1972   }
1973 }
1974 
1975 // Printing
1976 const char* _get_thread_state_name(JavaThreadState _thread_state) {
1977   switch (_thread_state) {
1978   case _thread_uninitialized:     return "_thread_uninitialized";
1979   case _thread_new:               return "_thread_new";
1980   case _thread_new_trans:         return "_thread_new_trans";
1981   case _thread_in_native:         return "_thread_in_native";
1982   case _thread_in_native_trans:   return "_thread_in_native_trans";
1983   case _thread_in_vm:             return "_thread_in_vm";
1984   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1985   case _thread_in_Java:           return "_thread_in_Java";
1986   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1987   case _thread_blocked:           return "_thread_blocked";
1988   case _thread_blocked_trans:     return "_thread_blocked_trans";
1989   default:                        return "unknown thread state";
1990   }
1991 }
1992 
1993 #ifndef PRODUCT
1994 void JavaThread::print_thread_state_on(outputStream *st) const {
1995   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1996 };
1997 #endif // PRODUCT
1998 
1999 // Called by Threads::print() for VM_PrintThreads operation
2000 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2001   st->print_raw("\"");
2002   st->print_raw(name());
2003   st->print_raw("\" ");
2004   oop thread_oop = threadObj();
2005   if (thread_oop != NULL) {
2006     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2007     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2008     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2009   }
2010   Thread::print_on(st, print_extended_info);
2011   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2012   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2013   if (thread_oop != NULL) {
2014     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2015   }
2016 #ifndef PRODUCT
2017   _safepoint_state->print_on(st);
2018 #endif // PRODUCT
2019   if (is_Compiler_thread()) {
2020     CompileTask *task = ((CompilerThread*)this)->task();
2021     if (task != NULL) {
2022       st->print("   Compiling: ");
2023       task->print(st, NULL, true, false);
2024     } else {
2025       st->print("   No compile task");
2026     }
2027     st->cr();
2028   }
2029 }
2030 
2031 void JavaThread::print() const { print_on(tty); }
2032 
2033 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2034   st->print("%s", get_thread_name_string(buf, buflen));
2035 }
2036 
2037 // Called by fatal error handler. The difference between this and
2038 // JavaThread::print() is that we can't grab lock or allocate memory.
2039 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2040   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
2041   oop thread_obj = threadObj();
2042   if (thread_obj != NULL) {
2043     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2044   }
2045   st->print(" [");
2046   st->print("%s", _get_thread_state_name(_thread_state));
2047   if (osthread()) {
2048     st->print(", id=%d", osthread()->thread_id());
2049   }
2050   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2051             p2i(stack_end()), p2i(stack_base()));
2052   st->print("]");
2053 
2054   ThreadsSMRSupport::print_info_on(this, st);
2055   return;
2056 }
2057 
2058 
2059 // Verification
2060 
2061 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2062   // ignore if there is no stack
2063   if (!has_last_Java_frame()) return;
2064   // traverse the stack frames. Starts from top frame.
2065   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2066     frame* fr = fst.current();
2067     f(fr, fst.register_map());
2068   }
2069 }
2070 
2071 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2072 
2073 void JavaThread::verify() {
2074   // Verify oops in the thread.
2075   oops_do(&VerifyOopClosure::verify_oop, NULL);
2076 
2077   // Verify the stack frames.
2078   frames_do(frame_verify);
2079 }
2080 
2081 // CR 6300358 (sub-CR 2137150)
2082 // Most callers of this method assume that it can't return NULL but a
2083 // thread may not have a name whilst it is in the process of attaching to
2084 // the VM - see CR 6412693, and there are places where a JavaThread can be
2085 // seen prior to having its threadObj set (e.g., JNI attaching threads and
2086 // if vm exit occurs during initialization). These cases can all be accounted
2087 // for such that this method never returns NULL.
2088 const char* JavaThread::name() const  {
2089   if (Thread::is_JavaThread_protected(/* target */ this)) {
2090     // The target JavaThread is protected so get_thread_name_string() is safe:
2091     return get_thread_name_string();
2092   }
2093 
2094   // The target JavaThread is not protected so we return the default:
2095   return Thread::name();
2096 }
2097 
2098 // Returns a non-NULL representation of this thread's name, or a suitable
2099 // descriptive string if there is no set name.
2100 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2101   const char* name_str;
2102   oop thread_obj = threadObj();
2103   if (thread_obj != NULL) {
2104     oop name = java_lang_Thread::name(thread_obj);
2105     if (name != NULL) {
2106       if (buf == NULL) {
2107         name_str = java_lang_String::as_utf8_string(name);
2108       } else {
2109         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2110       }
2111     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2112       name_str = "<no-name - thread is attaching>";
2113     } else {
2114       name_str = "<un-named>";
2115     }
2116   } else {
2117     name_str = Thread::name();
2118   }
2119   assert(name_str != NULL, "unexpected NULL thread name");
2120   return name_str;
2121 }
2122 
2123 // Helper to extract the name from the thread oop for logging.
2124 const char* JavaThread::name_for(oop thread_obj) {
2125   assert(thread_obj != NULL, "precondition");
2126   oop name = java_lang_Thread::name(thread_obj);
2127   const char* name_str;
2128   if (name != NULL) {
2129     name_str = java_lang_String::as_utf8_string(name);
2130   } else {
2131     name_str = "<un-named>";
2132   }
2133   return name_str;
2134 }
2135 
2136 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2137 
2138   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2139   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
2140   // Link Java Thread object <-> C++ Thread
2141 
2142   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2143   // and put it into a new Handle.  The Handle "thread_oop" can then
2144   // be used to pass the C++ thread object to other methods.
2145 
2146   // Set the Java level thread object (jthread) field of the
2147   // new thread (a JavaThread *) to C++ thread object using the
2148   // "thread_oop" handle.
2149 
2150   // Set the thread field (a JavaThread *) of the
2151   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2152 
2153   Handle thread_oop(Thread::current(),
2154                     JNIHandles::resolve_non_null(jni_thread));
2155   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2156          "must be initialized");
2157   set_threadObj(thread_oop());
2158   java_lang_Thread::set_thread(thread_oop(), this);
2159 
2160   if (prio == NoPriority) {
2161     prio = java_lang_Thread::priority(thread_oop());
2162     assert(prio != NoPriority, "A valid priority should be present");
2163   }
2164 
2165   // Push the Java priority down to the native thread; needs Threads_lock
2166   Thread::set_priority(this, prio);
2167 
2168   // Add the new thread to the Threads list and set it in motion.
2169   // We must have threads lock in order to call Threads::add.
2170   // It is crucial that we do not block before the thread is
2171   // added to the Threads list for if a GC happens, then the java_thread oop
2172   // will not be visited by GC.
2173   Threads::add(this);
2174 }
2175 
2176 oop JavaThread::current_park_blocker() {
2177   // Support for JSR-166 locks
2178   oop thread_oop = threadObj();
2179   if (thread_oop != NULL) {
2180     return java_lang_Thread::park_blocker(thread_oop);
2181   }
2182   return NULL;
2183 }
2184 
2185 
2186 void JavaThread::print_stack_on(outputStream* st) {
2187   if (!has_last_Java_frame()) return;
2188 
2189   Thread* current_thread = Thread::current();
2190   ResourceMark rm(current_thread);
2191   HandleMark hm(current_thread);
2192 
2193   RegisterMap reg_map(this);
2194   vframe* start_vf = last_java_vframe(&reg_map);
2195   int count = 0;
2196   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
2197     if (f->is_java_frame()) {
2198       javaVFrame* jvf = javaVFrame::cast(f);
2199       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2200 
2201       // Print out lock information
2202       if (JavaMonitorsInStackTrace) {
2203         jvf->print_lock_info_on(st, count);
2204       }
2205     } else {
2206       // Ignore non-Java frames
2207     }
2208 
2209     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
2210     count++;
2211     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
2212   }
2213 }
2214 
2215 
2216 // JVMTI PopFrame support
2217 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2218   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2219   if (in_bytes(size_in_bytes) != 0) {
2220     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2221     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2222     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2223   }
2224 }
2225 
2226 void* JavaThread::popframe_preserved_args() {
2227   return _popframe_preserved_args;
2228 }
2229 
2230 ByteSize JavaThread::popframe_preserved_args_size() {
2231   return in_ByteSize(_popframe_preserved_args_size);
2232 }
2233 
2234 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2235   int sz = in_bytes(popframe_preserved_args_size());
2236   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2237   return in_WordSize(sz / wordSize);
2238 }
2239 
2240 void JavaThread::popframe_free_preserved_args() {
2241   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2242   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
2243   _popframe_preserved_args = NULL;
2244   _popframe_preserved_args_size = 0;
2245 }
2246 
2247 #ifndef PRODUCT
2248 
2249 void JavaThread::trace_frames() {
2250   tty->print_cr("[Describe stack]");
2251   int frame_no = 1;
2252   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2253     tty->print("  %d. ", frame_no++);
2254     fst.current()->print_value_on(tty, this);
2255     tty->cr();
2256   }
2257 }
2258 
2259 class PrintAndVerifyOopClosure: public OopClosure {
2260  protected:
2261   template <class T> inline void do_oop_work(T* p) {
2262     oop obj = RawAccess<>::oop_load(p);
2263     if (obj == NULL) return;
2264     tty->print(INTPTR_FORMAT ": ", p2i(p));
2265     if (oopDesc::is_oop_or_null(obj)) {
2266       if (obj->is_objArray()) {
2267         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
2268       } else {
2269         obj->print();
2270       }
2271     } else {
2272       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
2273     }
2274     tty->cr();
2275   }
2276  public:
2277   virtual void do_oop(oop* p) { do_oop_work(p); }
2278   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
2279 };
2280 
2281 #ifdef ASSERT
2282 // Print or validate the layout of stack frames
2283 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2284   ResourceMark rm;
2285   PreserveExceptionMark pm(this);
2286   FrameValues values;
2287   int frame_no = 0;
2288   for (StackFrameStream fst(this, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2289     fst.current()->describe(values, ++frame_no);
2290     if (depth == frame_no) break;
2291   }
2292   if (validate_only) {
2293     values.validate();
2294   } else {
2295     tty->print_cr("[Describe stack layout]");
2296     values.print(this);
2297   }
2298 }
2299 #endif
2300 
2301 void JavaThread::trace_stack_from(vframe* start_vf) {
2302   ResourceMark rm;
2303   int vframe_no = 1;
2304   for (vframe* f = start_vf; f; f = f->sender()) {
2305     if (f->is_java_frame()) {
2306       javaVFrame::cast(f)->print_activation(vframe_no++);
2307     } else {
2308       f->print();
2309     }
2310     if (vframe_no > StackPrintLimit) {
2311       tty->print_cr("...<more frames>...");
2312       return;
2313     }
2314   }
2315 }
2316 
2317 
2318 void JavaThread::trace_stack() {
2319   if (!has_last_Java_frame()) return;
2320   Thread* current_thread = Thread::current();
2321   ResourceMark rm(current_thread);
2322   HandleMark hm(current_thread);
2323   RegisterMap reg_map(this);
2324   trace_stack_from(last_java_vframe(&reg_map));
2325 }
2326 
2327 
2328 #endif // PRODUCT
2329 
2330 
2331 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2332   assert(reg_map != NULL, "a map must be given");
2333   frame f = last_frame();
2334   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2335     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2336   }
2337   return NULL;
2338 }
2339 
2340 
2341 Klass* JavaThread::security_get_caller_class(int depth) {
2342   vframeStream vfst(this);
2343   vfst.security_get_caller_frame(depth);
2344   if (!vfst.at_end()) {
2345     return vfst.method()->method_holder();
2346   }
2347   return NULL;
2348 }
2349 
2350 // java.lang.Thread.sleep support
2351 // Returns true if sleep time elapsed as expected, and false
2352 // if the thread was interrupted.
2353 bool JavaThread::sleep(jlong millis) {
2354   assert(this == Thread::current(),  "thread consistency check");
2355 
2356   ParkEvent * const slp = this->_SleepEvent;
2357   // Because there can be races with thread interruption sending an unpark()
2358   // to the event, we explicitly reset it here to avoid an immediate return.
2359   // The actual interrupt state will be checked before we park().
2360   slp->reset();
2361   // Thread interruption establishes a happens-before ordering in the
2362   // Java Memory Model, so we need to ensure we synchronize with the
2363   // interrupt state.
2364   OrderAccess::fence();
2365 
2366   jlong prevtime = os::javaTimeNanos();
2367 
2368   for (;;) {
2369     // interruption has precedence over timing out
2370     if (this->is_interrupted(true)) {
2371       return false;
2372     }
2373 
2374     if (millis <= 0) {
2375       return true;
2376     }
2377 
2378     {
2379       ThreadBlockInVM tbivm(this);
2380       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2381       slp->park(millis);
2382     }
2383 
2384     // Update elapsed time tracking
2385     jlong newtime = os::javaTimeNanos();
2386     if (newtime - prevtime < 0) {
2387       // time moving backwards, should only happen if no monotonic clock
2388       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2389       assert(false,
2390              "unexpected time moving backwards detected in JavaThread::sleep()");
2391     } else {
2392       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2393     }
2394     prevtime = newtime;
2395   }
2396 }
2397 
2398 
2399 // ======= Threads ========
2400 
2401 // The Threads class links together all active threads, and provides
2402 // operations over all threads. It is protected by the Threads_lock,
2403 // which is also used in other global contexts like safepointing.
2404 // ThreadsListHandles are used to safely perform operations on one
2405 // or more threads without the risk of the thread exiting during the
2406 // operation.
2407 //
2408 // Note: The Threads_lock is currently more widely used than we
2409 // would like. We are actively migrating Threads_lock uses to other
2410 // mechanisms in order to reduce Threads_lock contention.
2411 
2412 int         Threads::_number_of_threads = 0;
2413 int         Threads::_number_of_non_daemon_threads = 0;
2414 int         Threads::_return_code = 0;
2415 uintx       Threads::_thread_claim_token = 1; // Never zero.
2416 size_t      JavaThread::_stack_size_at_create = 0;
2417 
2418 #ifdef ASSERT
2419 bool        Threads::_vm_complete = false;
2420 #endif
2421 
2422 // All NonJavaThreads (i.e., every non-JavaThread in the system).
2423 void Threads::non_java_threads_do(ThreadClosure* tc) {
2424   NoSafepointVerifier nsv;
2425   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
2426     tc->do_thread(njti.current());
2427   }
2428 }
2429 
2430 // All JavaThreads
2431 #define ALL_JAVA_THREADS(X) \
2432   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
2433 
2434 // All JavaThreads
2435 void Threads::java_threads_do(ThreadClosure* tc) {
2436   assert_locked_or_safepoint(Threads_lock);
2437   // ALL_JAVA_THREADS iterates through all JavaThreads.
2438   ALL_JAVA_THREADS(p) {
2439     tc->do_thread(p);
2440   }
2441 }
2442 
2443 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
2444   assert_locked_or_safepoint(Threads_lock);
2445   java_threads_do(tc);
2446   tc->do_thread(VMThread::vm_thread());
2447 }
2448 
2449 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
2450 void Threads::threads_do(ThreadClosure* tc) {
2451   assert_locked_or_safepoint(Threads_lock);
2452   java_threads_do(tc);
2453   non_java_threads_do(tc);
2454 }
2455 
2456 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
2457   uintx claim_token = Threads::thread_claim_token();
2458   ALL_JAVA_THREADS(p) {
2459     if (p->claim_threads_do(is_par, claim_token)) {
2460       tc->do_thread(p);
2461     }
2462   }
2463   VMThread* vmt = VMThread::vm_thread();
2464   if (vmt->claim_threads_do(is_par, claim_token)) {
2465     tc->do_thread(vmt);
2466   }
2467 }
2468 
2469 // The system initialization in the library has three phases.
2470 //
2471 // Phase 1: java.lang.System class initialization
2472 //     java.lang.System is a primordial class loaded and initialized
2473 //     by the VM early during startup.  java.lang.System.<clinit>
2474 //     only does registerNatives and keeps the rest of the class
2475 //     initialization work later until thread initialization completes.
2476 //
2477 //     System.initPhase1 initializes the system properties, the static
2478 //     fields in, out, and err. Set up java signal handlers, OS-specific
2479 //     system settings, and thread group of the main thread.
2480 static void call_initPhase1(TRAPS) {
2481   Klass* klass = vmClasses::System_klass();
2482   JavaValue result(T_VOID);
2483   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
2484                                          vmSymbols::void_method_signature(), CHECK);
2485 }
2486 
2487 // Phase 2. Module system initialization
2488 //     This will initialize the module system.  Only java.base classes
2489 //     can be loaded until phase 2 completes.
2490 //
2491 //     Call System.initPhase2 after the compiler initialization and jsr292
2492 //     classes get initialized because module initialization runs a lot of java
2493 //     code, that for performance reasons, should be compiled.  Also, this will
2494 //     enable the startup code to use lambda and other language features in this
2495 //     phase and onward.
2496 //
2497 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
2498 static void call_initPhase2(TRAPS) {
2499   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
2500 
2501   Klass* klass = vmClasses::System_klass();
2502 
2503   JavaValue result(T_INT);
2504   JavaCallArguments args;
2505   args.push_int(DisplayVMOutputToStderr);
2506   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
2507   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
2508                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
2509   if (result.get_jint() != JNI_OK) {
2510     vm_exit_during_initialization(); // no message or exception
2511   }
2512 
2513   universe_post_module_init();
2514 }
2515 
2516 // Phase 3. final setup - set security manager, system class loader and TCCL
2517 //
2518 //     This will instantiate and set the security manager, set the system class
2519 //     loader as well as the thread context class loader.  The security manager
2520 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
2521 //     other modules or the application's classpath.
2522 static void call_initPhase3(TRAPS) {
2523   Klass* klass = vmClasses::System_klass();
2524   JavaValue result(T_VOID);
2525   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
2526                                          vmSymbols::void_method_signature(), CHECK);
2527 }
2528 
2529 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
2530   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
2531 
2532   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2533     create_vm_init_libraries();
2534   }
2535 
2536   initialize_class(vmSymbols::java_lang_String(), CHECK);
2537 
2538   // Inject CompactStrings value after the static initializers for String ran.
2539   java_lang_String::set_compact_strings(CompactStrings);
2540 
2541   // Initialize java_lang.System (needed before creating the thread)
2542   initialize_class(vmSymbols::java_lang_System(), CHECK);
2543   // The VM creates & returns objects of this class. Make sure it's initialized.
2544   initialize_class(vmSymbols::java_lang_Class(), CHECK);
2545   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
2546   Handle thread_group = create_initial_thread_group(CHECK);
2547   Universe::set_main_thread_group(thread_group());
2548   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
2549   create_initial_thread(thread_group, main_thread, CHECK);
2550 
2551   // The VM creates objects of this class.
2552   initialize_class(vmSymbols::java_lang_Module(), CHECK);
2553 
2554 #ifdef ASSERT
2555   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
2556   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
2557 #endif
2558 
2559   // initialize the hardware-specific constants needed by Unsafe
2560   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
2561   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
2562 
2563   // The VM preresolves methods to these classes. Make sure that they get initialized
2564   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
2565   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
2566 
2567   // Phase 1 of the system initialization in the library, java.lang.System class initialization
2568   call_initPhase1(CHECK);
2569 
2570   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
2571   // Some values are actually configure-time constants but some can be set via the jlink tool and
2572   // so must be read dynamically. We treat them all the same.
2573   InstanceKlass* ik = SystemDictionary::find_instance_klass(vmSymbols::java_lang_VersionProps(),
2574                                                             Handle(), Handle());
2575   {
2576     ResourceMark rm(main_thread);
2577     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
2578 
2579     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
2580 
2581     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
2582 
2583     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
2584 
2585     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
2586   }
2587 
2588   // an instance of OutOfMemory exception has been allocated earlier
2589   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
2590   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
2591   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
2592   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
2593   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
2594   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
2595   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
2596   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
2597 }
2598 
2599 void Threads::initialize_jsr292_core_classes(TRAPS) {
2600   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
2601 
2602   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
2603   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
2604   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
2605   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
2606 }
2607 
2608 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2609   extern void JDK_Version_init();
2610 
2611   // Preinitialize version info.
2612   VM_Version::early_initialize();
2613 
2614   // Check version
2615   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2616 
2617   // Initialize library-based TLS
2618   ThreadLocalStorage::init();
2619 
2620   // Initialize the output stream module
2621   ostream_init();
2622 
2623   // Process java launcher properties.
2624   Arguments::process_sun_java_launcher_properties(args);
2625 
2626   // Initialize the os module
2627   os::init();
2628 
2629   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
2630 
2631   // Record VM creation timing statistics
2632   TraceVmCreationTime create_vm_timer;
2633   create_vm_timer.start();
2634 
2635   // Initialize system properties.
2636   Arguments::init_system_properties();
2637 
2638   // So that JDK version can be used as a discriminator when parsing arguments
2639   JDK_Version_init();
2640 
2641   // Update/Initialize System properties after JDK version number is known
2642   Arguments::init_version_specific_system_properties();
2643 
2644   // Make sure to initialize log configuration *before* parsing arguments
2645   LogConfiguration::initialize(create_vm_timer.begin_time());
2646 
2647   // Parse arguments
2648   // Note: this internally calls os::init_container_support()
2649   jint parse_result = Arguments::parse(args);
2650   if (parse_result != JNI_OK) return parse_result;
2651 
2652   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
2653   MemTracker::initialize();
2654 
2655   os::init_before_ergo();
2656 
2657   jint ergo_result = Arguments::apply_ergo();
2658   if (ergo_result != JNI_OK) return ergo_result;
2659 
2660   // Final check of all ranges after ergonomics which may change values.
2661   if (!JVMFlagLimit::check_all_ranges()) {
2662     return JNI_EINVAL;
2663   }
2664 
2665   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
2666   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
2667   if (!constraint_result) {
2668     return JNI_EINVAL;
2669   }
2670 
2671   if (PauseAtStartup) {
2672     os::pause();
2673   }
2674 
2675   HOTSPOT_VM_INIT_BEGIN();
2676 
2677   // Timing (must come after argument parsing)
2678   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
2679 
2680   // Initialize the os module after parsing the args
2681   jint os_init_2_result = os::init_2();
2682   if (os_init_2_result != JNI_OK) return os_init_2_result;
2683 
2684 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
2685   // Initialize assert poison page mechanism.
2686   if (ShowRegistersOnAssert) {
2687     initialize_assert_poison();
2688   }
2689 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
2690 
2691   SafepointMechanism::initialize();
2692 
2693   jint adjust_after_os_result = Arguments::adjust_after_os();
2694   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
2695 
2696   // Initialize output stream logging
2697   ostream_init_log();
2698 
2699   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2700   // Must be before create_vm_init_agents()
2701   if (Arguments::init_libraries_at_startup()) {
2702     convert_vm_init_libraries_to_agents();
2703   }
2704 
2705   // Launch -agentlib/-agentpath and converted -Xrun agents
2706   if (Arguments::init_agents_at_startup()) {
2707     create_vm_init_agents();
2708   }
2709 
2710   // Initialize Threads state
2711   _number_of_threads = 0;
2712   _number_of_non_daemon_threads = 0;
2713 
2714   // Initialize global data structures and create system classes in heap
2715   vm_init_globals();
2716 
2717 #if INCLUDE_JVMCI
2718   if (JVMCICounterSize > 0) {
2719     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
2720     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
2721   } else {
2722     JavaThread::_jvmci_old_thread_counters = NULL;
2723   }
2724 #endif // INCLUDE_JVMCI
2725 
2726   // Initialize OopStorage for threadObj
2727   _thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
2728 
2729   // Attach the main thread to this os thread
2730   JavaThread* main_thread = new JavaThread();
2731   main_thread->set_thread_state(_thread_in_vm);
2732   main_thread->initialize_thread_current();
2733   // must do this before set_active_handles
2734   main_thread->record_stack_base_and_size();
2735   main_thread->register_thread_stack_with_NMT();
2736   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2737   MACOS_AARCH64_ONLY(main_thread->init_wx());
2738 
2739   if (!main_thread->set_as_starting_thread()) {
2740     vm_shutdown_during_initialization(
2741                                       "Failed necessary internal allocation. Out of swap space");
2742     main_thread->smr_delete();
2743     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2744     return JNI_ENOMEM;
2745   }
2746 
2747   // Enable guard page *after* os::create_main_thread(), otherwise it would
2748   // crash Linux VM, see notes in os_linux.cpp.
2749   main_thread->stack_overflow_state()->create_stack_guard_pages();
2750 
2751   // Initialize Java-Level synchronization subsystem
2752   ObjectMonitor::Initialize();
2753   ObjectSynchronizer::initialize();
2754 
2755   // Initialize global modules
2756   jint status = init_globals();
2757   if (status != JNI_OK) {
2758     main_thread->smr_delete();
2759     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2760     return status;
2761   }
2762 
2763   JFR_ONLY(Jfr::on_create_vm_1();)
2764 
2765   // Should be done after the heap is fully created
2766   main_thread->cache_global_variables();
2767 
2768   { MutexLocker mu(Threads_lock);
2769     Threads::add(main_thread);
2770   }
2771 
2772   // Any JVMTI raw monitors entered in onload will transition into
2773   // real raw monitor. VM is setup enough here for raw monitor enter.
2774   JvmtiExport::transition_pending_onload_raw_monitors();
2775 
2776   // Create the VMThread
2777   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
2778 
2779     VMThread::create();
2780     VMThread* vmthread = VMThread::vm_thread();
2781 
2782     if (!os::create_thread(vmthread, os::vm_thread)) {
2783       vm_exit_during_initialization("Cannot create VM thread. "
2784                                     "Out of system resources.");
2785     }
2786 
2787     // Wait for the VM thread to become ready, and VMThread::run to initialize
2788     // Monitors can have spurious returns, must always check another state flag
2789     {
2790       MonitorLocker ml(Notify_lock);
2791       os::start_thread(vmthread);
2792       while (!vmthread->is_running()) {
2793         ml.wait();
2794       }
2795     }
2796   }
2797 
2798   assert(Universe::is_fully_initialized(), "not initialized");
2799   if (VerifyDuringStartup) {
2800     // Make sure we're starting with a clean slate.
2801     VM_Verify verify_op;
2802     VMThread::execute(&verify_op);
2803   }
2804 
2805   // We need this to update the java.vm.info property in case any flags used
2806   // to initially define it have been changed. This is needed for both CDS
2807   // since UseSharedSpaces may be changed after java.vm.info
2808   // is initially computed. See Abstract_VM_Version::vm_info_string().
2809   // This update must happen before we initialize the java classes, but
2810   // after any initialization logic that might modify the flags.
2811   Arguments::update_vm_info_property(VM_Version::vm_info_string());
2812 
2813   JavaThread* THREAD = JavaThread::current(); // For exception macros.
2814   HandleMark hm(THREAD);
2815 
2816   // Always call even when there are not JVMTI environments yet, since environments
2817   // may be attached late and JVMTI must track phases of VM execution
2818   JvmtiExport::enter_early_start_phase();
2819 
2820   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2821   JvmtiExport::post_early_vm_start();
2822 
2823   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
2824 
2825   quicken_jni_functions();
2826 
2827   // No more stub generation allowed after that point.
2828   StubCodeDesc::freeze();
2829 
2830   // Set flag that basic initialization has completed. Used by exceptions and various
2831   // debug stuff, that does not work until all basic classes have been initialized.
2832   set_init_completed();
2833 
2834   LogConfiguration::post_initialize();
2835   Metaspace::post_initialize();
2836 
2837   HOTSPOT_VM_INIT_END();
2838 
2839   // record VM initialization completion time
2840 #if INCLUDE_MANAGEMENT
2841   Management::record_vm_init_completed();
2842 #endif // INCLUDE_MANAGEMENT
2843 
2844   // Signal Dispatcher needs to be started before VMInit event is posted
2845   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
2846 
2847   // Start Attach Listener if +StartAttachListener or it can't be started lazily
2848   if (!DisableAttachMechanism) {
2849     AttachListener::vm_start();
2850     if (StartAttachListener || AttachListener::init_at_startup()) {
2851       AttachListener::init();
2852     }
2853   }
2854 
2855   // Launch -Xrun agents
2856   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
2857   // back-end can launch with -Xdebug -Xrunjdwp.
2858   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
2859     create_vm_init_libraries();
2860   }
2861 
2862   Chunk::start_chunk_pool_cleaner_task();
2863 
2864   // Start the service thread
2865   // The service thread enqueues JVMTI deferred events and does various hashtable
2866   // and other cleanups.  Needs to start before the compilers start posting events.
2867   ServiceThread::initialize();
2868 
2869   // Start the monitor deflation thread:
2870   MonitorDeflationThread::initialize();
2871 
2872   // initialize compiler(s)
2873 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
2874 #if INCLUDE_JVMCI
2875   bool force_JVMCI_intialization = false;
2876   if (EnableJVMCI) {
2877     // Initialize JVMCI eagerly when it is explicitly requested.
2878     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
2879     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
2880 
2881     if (!force_JVMCI_intialization) {
2882       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
2883       // compilations via JVMCI will not actually block until JVMCI is initialized.
2884       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
2885     }
2886   }
2887 #endif
2888   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
2889   // Postpone completion of compiler initialization to after JVMCI
2890   // is initialized to avoid timeouts of blocking compilations.
2891   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
2892     CompileBroker::compilation_init_phase2();
2893   }
2894 #endif
2895 
2896   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
2897   // It is done after compilers are initialized, because otherwise compilations of
2898   // signature polymorphic MH intrinsics can be missed
2899   // (see SystemDictionary::find_method_handle_intrinsic).
2900   initialize_jsr292_core_classes(CHECK_JNI_ERR);
2901 
2902   // This will initialize the module system.  Only java.base classes can be
2903   // loaded until phase 2 completes
2904   call_initPhase2(CHECK_JNI_ERR);
2905 
2906   JFR_ONLY(Jfr::on_create_vm_2();)
2907 
2908   // Always call even when there are not JVMTI environments yet, since environments
2909   // may be attached late and JVMTI must track phases of VM execution
2910   JvmtiExport::enter_start_phase();
2911 
2912   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2913   JvmtiExport::post_vm_start();
2914 
2915   // Final system initialization including security manager and system class loader
2916   call_initPhase3(CHECK_JNI_ERR);
2917 
2918   // cache the system and platform class loaders
2919   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
2920 
2921 #if INCLUDE_CDS
2922   // capture the module path info from the ModuleEntryTable
2923   ClassLoader::initialize_module_path(THREAD);
2924   if (HAS_PENDING_EXCEPTION) {
2925     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
2926     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
2927   }
2928 #endif
2929 
2930 #if INCLUDE_JVMCI
2931   if (force_JVMCI_intialization) {
2932     JVMCI::initialize_compiler(CHECK_JNI_ERR);
2933     CompileBroker::compilation_init_phase2();
2934   }
2935 #endif
2936 
2937   // Always call even when there are not JVMTI environments yet, since environments
2938   // may be attached late and JVMTI must track phases of VM execution
2939   JvmtiExport::enter_live_phase();
2940 
2941   // Make perfmemory accessible
2942   PerfMemory::set_accessible(true);
2943 
2944   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
2945   JvmtiExport::post_vm_initialized();
2946 
2947   JFR_ONLY(Jfr::on_create_vm_3();)
2948 
2949 #if INCLUDE_MANAGEMENT
2950   Management::initialize(THREAD);
2951 
2952   if (HAS_PENDING_EXCEPTION) {
2953     // management agent fails to start possibly due to
2954     // configuration problem and is responsible for printing
2955     // stack trace if appropriate. Simply exit VM.
2956     vm_exit(1);
2957   }
2958 #endif // INCLUDE_MANAGEMENT
2959 
2960   StatSampler::engage();
2961   if (CheckJNICalls)                  JniPeriodicChecker::engage();
2962 
2963 #if INCLUDE_RTM_OPT
2964   RTMLockingCounters::init();
2965 #endif
2966 
2967   call_postVMInitHook(THREAD);
2968   // The Java side of PostVMInitHook.run must deal with all
2969   // exceptions and provide means of diagnosis.
2970   if (HAS_PENDING_EXCEPTION) {
2971     CLEAR_PENDING_EXCEPTION;
2972   }
2973 
2974   {
2975     MutexLocker ml(PeriodicTask_lock);
2976     // Make sure the WatcherThread can be started by WatcherThread::start()
2977     // or by dynamic enrollment.
2978     WatcherThread::make_startable();
2979     // Start up the WatcherThread if there are any periodic tasks
2980     // NOTE:  All PeriodicTasks should be registered by now. If they
2981     //   aren't, late joiners might appear to start slowly (we might
2982     //   take a while to process their first tick).
2983     if (PeriodicTask::num_tasks() > 0) {
2984       WatcherThread::start();
2985     }
2986   }
2987 
2988   create_vm_timer.end();
2989 #ifdef ASSERT
2990   _vm_complete = true;
2991 #endif
2992 
2993   if (DumpSharedSpaces) {
2994     MetaspaceShared::preload_and_dump();
2995     ShouldNotReachHere();
2996   }
2997 
2998   return JNI_OK;
2999 }
3000 
3001 // type for the Agent_OnLoad and JVM_OnLoad entry points
3002 extern "C" {
3003   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3004 }
3005 // Find a command line agent library and return its entry point for
3006 //         -agentlib:  -agentpath:   -Xrun
3007 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3008 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3009                                     const char *on_load_symbols[],
3010                                     size_t num_symbol_entries) {
3011   OnLoadEntry_t on_load_entry = NULL;
3012   void *library = NULL;
3013 
3014   if (!agent->valid()) {
3015     char buffer[JVM_MAXPATHLEN];
3016     char ebuf[1024] = "";
3017     const char *name = agent->name();
3018     const char *msg = "Could not find agent library ";
3019 
3020     // First check to see if agent is statically linked into executable
3021     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3022       library = agent->os_lib();
3023     } else if (agent->is_absolute_path()) {
3024       library = os::dll_load(name, ebuf, sizeof ebuf);
3025       if (library == NULL) {
3026         const char *sub_msg = " in absolute path, with error: ";
3027         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3028         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3029         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3030         // If we can't find the agent, exit.
3031         vm_exit_during_initialization(buf, NULL);
3032         FREE_C_HEAP_ARRAY(char, buf);
3033       }
3034     } else {
3035       // Try to load the agent from the standard dll directory
3036       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3037                              name)) {
3038         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3039       }
3040       if (library == NULL) { // Try the library path directory.
3041         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3042           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3043         }
3044         if (library == NULL) {
3045           const char *sub_msg = " on the library path, with error: ";
3046           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3047 
3048           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3049                        strlen(ebuf) + strlen(sub_msg2) + 1;
3050           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3051           if (!agent->is_instrument_lib()) {
3052             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3053           } else {
3054             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
3055           }
3056           // If we can't find the agent, exit.
3057           vm_exit_during_initialization(buf, NULL);
3058           FREE_C_HEAP_ARRAY(char, buf);
3059         }
3060       }
3061     }
3062     agent->set_os_lib(library);
3063     agent->set_valid();
3064   }
3065 
3066   // Find the OnLoad function.
3067   on_load_entry =
3068     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3069                                                           false,
3070                                                           on_load_symbols,
3071                                                           num_symbol_entries));
3072   return on_load_entry;
3073 }
3074 
3075 // Find the JVM_OnLoad entry point
3076 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3077   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3078   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3079 }
3080 
3081 // Find the Agent_OnLoad entry point
3082 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3083   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3084   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3085 }
3086 
3087 // For backwards compatibility with -Xrun
3088 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3089 // treated like -agentpath:
3090 // Must be called before agent libraries are created
3091 void Threads::convert_vm_init_libraries_to_agents() {
3092   AgentLibrary* agent;
3093   AgentLibrary* next;
3094 
3095   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3096     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3097     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3098 
3099     // If there is an JVM_OnLoad function it will get called later,
3100     // otherwise see if there is an Agent_OnLoad
3101     if (on_load_entry == NULL) {
3102       on_load_entry = lookup_agent_on_load(agent);
3103       if (on_load_entry != NULL) {
3104         // switch it to the agent list -- so that Agent_OnLoad will be called,
3105         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3106         Arguments::convert_library_to_agent(agent);
3107       } else {
3108         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3109       }
3110     }
3111   }
3112 }
3113 
3114 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3115 // Invokes Agent_OnLoad
3116 // Called very early -- before JavaThreads exist
3117 void Threads::create_vm_init_agents() {
3118   extern struct JavaVM_ main_vm;
3119   AgentLibrary* agent;
3120 
3121   JvmtiExport::enter_onload_phase();
3122 
3123   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3124     // CDS dumping does not support native JVMTI agent.
3125     // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
3126     if (Arguments::is_dumping_archive()) {
3127       if(!agent->is_instrument_lib()) {
3128         vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
3129       } else if (!AllowArchivingWithJavaAgent) {
3130         vm_exit_during_cds_dumping(
3131           "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
3132       }
3133     }
3134 
3135     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3136 
3137     if (on_load_entry != NULL) {
3138       // Invoke the Agent_OnLoad function
3139       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3140       if (err != JNI_OK) {
3141         vm_exit_during_initialization("agent library failed to init", agent->name());
3142       }
3143     } else {
3144       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3145     }
3146   }
3147 
3148   JvmtiExport::enter_primordial_phase();
3149 }
3150 
3151 extern "C" {
3152   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3153 }
3154 
3155 void Threads::shutdown_vm_agents() {
3156   // Send any Agent_OnUnload notifications
3157   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3158   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3159   extern struct JavaVM_ main_vm;
3160   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3161 
3162     // Find the Agent_OnUnload function.
3163     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3164                                                    os::find_agent_function(agent,
3165                                                    false,
3166                                                    on_unload_symbols,
3167                                                    num_symbol_entries));
3168 
3169     // Invoke the Agent_OnUnload function
3170     if (unload_entry != NULL) {
3171       JavaThread* thread = JavaThread::current();
3172       ThreadToNativeFromVM ttn(thread);
3173       HandleMark hm(thread);
3174       (*unload_entry)(&main_vm);
3175     }
3176   }
3177 }
3178 
3179 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3180 // Invokes JVM_OnLoad
3181 void Threads::create_vm_init_libraries() {
3182   extern struct JavaVM_ main_vm;
3183   AgentLibrary* agent;
3184 
3185   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3186     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3187 
3188     if (on_load_entry != NULL) {
3189       // Invoke the JVM_OnLoad function
3190       JavaThread* thread = JavaThread::current();
3191       ThreadToNativeFromVM ttn(thread);
3192       HandleMark hm(thread);
3193       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3194       if (err != JNI_OK) {
3195         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3196       }
3197     } else {
3198       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3199     }
3200   }
3201 }
3202 
3203 
3204 // Last thread running calls java.lang.Shutdown.shutdown()
3205 void JavaThread::invoke_shutdown_hooks() {
3206   HandleMark hm(this);
3207 
3208   // We could get here with a pending exception, if so clear it now or
3209   // it will cause MetaspaceShared::link_shared_classes to
3210   // fail for dynamic dump.
3211   if (this->has_pending_exception()) {
3212     this->clear_pending_exception();
3213   }
3214 
3215 #if INCLUDE_CDS
3216   // Link all classes for dynamic CDS dumping before vm exit.
3217   // Same operation is being done in JVM_BeforeHalt for handling the
3218   // case where the application calls System.exit().
3219   if (DynamicArchive::should_dump_at_vm_exit()) {
3220     DynamicArchive::prepare_for_dump_at_exit();
3221   }
3222 #endif
3223 
3224   EXCEPTION_MARK;
3225   Klass* shutdown_klass =
3226     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3227                                       THREAD);
3228   if (shutdown_klass != NULL) {
3229     // SystemDictionary::resolve_or_null will return null if there was
3230     // an exception.  If we cannot load the Shutdown class, just don't
3231     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3232     // won't be run.  Note that if a shutdown hook was registered,
3233     // the Shutdown class would have already been loaded
3234     // (Runtime.addShutdownHook will load it).
3235     JavaValue result(T_VOID);
3236     JavaCalls::call_static(&result,
3237                            shutdown_klass,
3238                            vmSymbols::shutdown_name(),
3239                            vmSymbols::void_method_signature(),
3240                            THREAD);
3241   }
3242   CLEAR_PENDING_EXCEPTION;
3243 }
3244 
3245 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3246 // the program falls off the end of main(). Another VM exit path is through
3247 // vm_exit() when the program calls System.exit() to return a value or when
3248 // there is a serious error in VM. The two shutdown paths are not exactly
3249 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3250 // and VM_Exit op at VM level.
3251 //
3252 // Shutdown sequence:
3253 //   + Shutdown native memory tracking if it is on
3254 //   + Wait until we are the last non-daemon thread to execute
3255 //     <-- every thing is still working at this moment -->
3256 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3257 //        shutdown hooks
3258 //   + Call before_exit(), prepare for VM exit
3259 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3260 //        currently the only user of this mechanism is File.deleteOnExit())
3261 //      > stop StatSampler, watcher thread,
3262 //        post thread end and vm death events to JVMTI,
3263 //        stop signal thread
3264 //   + Call JavaThread::exit(), it will:
3265 //      > release JNI handle blocks, remove stack guard pages
3266 //      > remove this thread from Threads list
3267 //     <-- no more Java code from this thread after this point -->
3268 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3269 //     the compiler threads at safepoint
3270 //     <-- do not use anything that could get blocked by Safepoint -->
3271 //   + Disable tracing at JNI/JVM barriers
3272 //   + Set _vm_exited flag for threads that are still running native code
3273 //   + Call exit_globals()
3274 //      > deletes tty
3275 //      > deletes PerfMemory resources
3276 //   + Delete this thread
3277 //   + Return to caller
3278 
3279 void Threads::destroy_vm() {
3280   JavaThread* thread = JavaThread::current();
3281 
3282 #ifdef ASSERT
3283   _vm_complete = false;
3284 #endif
3285   // Wait until we are the last non-daemon thread to execute
3286   {
3287     MonitorLocker nu(Threads_lock);
3288     while (Threads::number_of_non_daemon_threads() > 1)
3289       // This wait should make safepoint checks, wait without a timeout.
3290       nu.wait(0);
3291   }
3292 
3293   EventShutdown e;
3294   if (e.should_commit()) {
3295     e.set_reason("No remaining non-daemon Java threads");
3296     e.commit();
3297   }
3298 
3299   // Hang forever on exit if we are reporting an error.
3300   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
3301     os::infinite_sleep();
3302   }
3303   os::wait_for_keypress_at_exit();
3304 
3305   // run Java level shutdown hooks
3306   thread->invoke_shutdown_hooks();
3307 
3308   before_exit(thread);
3309 
3310   thread->exit(true);
3311 
3312   // We are no longer on the main thread list but could still be in a
3313   // secondary list where another thread may try to interact with us.
3314   // So wait until all such interactions are complete before we bring
3315   // the VM to the termination safepoint. Normally this would be done
3316   // using thread->smr_delete() below where we delete the thread, but
3317   // we can't call that after the termination safepoint is active as
3318   // we will deadlock on the Threads_lock. Once all interactions are
3319   // complete it is safe to directly delete the thread at any time.
3320   ThreadsSMRSupport::wait_until_not_protected(thread);
3321 
3322   // Stop VM thread.
3323   {
3324     // 4945125 The vm thread comes to a safepoint during exit.
3325     // GC vm_operations can get caught at the safepoint, and the
3326     // heap is unparseable if they are caught. Grab the Heap_lock
3327     // to prevent this. The GC vm_operations will not be able to
3328     // queue until after the vm thread is dead. After this point,
3329     // we'll never emerge out of the safepoint before the VM exits.
3330     // Assert that the thread is terminated so that acquiring the
3331     // Heap_lock doesn't cause the terminated thread to participate in
3332     // the safepoint protocol.
3333 
3334     assert(thread->is_terminated(), "must be terminated here");
3335     MutexLocker ml(Heap_lock);
3336 
3337     VMThread::wait_for_vm_thread_exit();
3338     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3339     VMThread::destroy();
3340   }
3341 
3342   // Now, all Java threads are gone except daemon threads. Daemon threads
3343   // running Java code or in VM are stopped by the Safepoint. However,
3344   // daemon threads executing native code are still running.  But they
3345   // will be stopped at native=>Java/VM barriers. Note that we can't
3346   // simply kill or suspend them, as it is inherently deadlock-prone.
3347 
3348   VM_Exit::set_vm_exited();
3349 
3350   // Clean up ideal graph printers after the VMThread has started
3351   // the final safepoint which will block all the Compiler threads.
3352   // Note that this Thread has already logically exited so the
3353   // clean_up() function's use of a JavaThreadIteratorWithHandle
3354   // would be a problem except set_vm_exited() has remembered the
3355   // shutdown thread which is granted a policy exception.
3356 #if defined(COMPILER2) && !defined(PRODUCT)
3357   IdealGraphPrinter::clean_up();
3358 #endif
3359 
3360   notify_vm_shutdown();
3361 
3362   // exit_globals() will delete tty
3363   exit_globals();
3364 
3365   // Deleting the shutdown thread here is safe. See comment on
3366   // wait_until_not_protected() above.
3367   delete thread;
3368 
3369 #if INCLUDE_JVMCI
3370   if (JVMCICounterSize > 0) {
3371     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
3372   }
3373 #endif
3374 
3375   LogConfiguration::finalize();
3376 }
3377 
3378 
3379 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3380   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3381   return is_supported_jni_version(version);
3382 }
3383 
3384 
3385 jboolean Threads::is_supported_jni_version(jint version) {
3386   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3387   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3388   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3389   if (version == JNI_VERSION_1_8) return JNI_TRUE;
3390   if (version == JNI_VERSION_9) return JNI_TRUE;
3391   if (version == JNI_VERSION_10) return JNI_TRUE;
3392   return JNI_FALSE;
3393 }
3394 
3395 
3396 void Threads::add(JavaThread* p, bool force_daemon) {
3397   // The threads lock must be owned at this point
3398   assert(Threads_lock->owned_by_self(), "must have threads lock");
3399 
3400   BarrierSet::barrier_set()->on_thread_attach(p);
3401 
3402   // Once a JavaThread is added to the Threads list, smr_delete() has
3403   // to be used to delete it. Otherwise we can just delete it directly.
3404   p->set_on_thread_list();
3405 
3406   _number_of_threads++;
3407   oop threadObj = p->threadObj();
3408   bool daemon = true;
3409   // Bootstrapping problem: threadObj can be null for initial
3410   // JavaThread (or for threads attached via JNI)
3411   if ((!force_daemon) && !is_daemon((threadObj))) {
3412     _number_of_non_daemon_threads++;
3413     daemon = false;
3414   }
3415 
3416   ThreadService::add_thread(p, daemon);
3417 
3418   // Maintain fast thread list
3419   ThreadsSMRSupport::add_thread(p);
3420 
3421   // Increase the ObjectMonitor ceiling for the new thread.
3422   ObjectSynchronizer::inc_in_use_list_ceiling();
3423 
3424   // Possible GC point.
3425   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
3426 
3427   // Make new thread known to active EscapeBarrier
3428   EscapeBarrier::thread_added(p);
3429 }
3430 
3431 void Threads::remove(JavaThread* p, bool is_daemon) {
3432   // Extra scope needed for Thread_lock, so we can check
3433   // that we do not remove thread without safepoint code notice
3434   { MonitorLocker ml(Threads_lock);
3435 
3436     // BarrierSet state must be destroyed after the last thread transition
3437     // before the thread terminates. Thread transitions result in calls to
3438     // StackWatermarkSet::on_safepoint(), which performs GC processing,
3439     // requiring the GC state to be alive.
3440     BarrierSet::barrier_set()->on_thread_detach(p);
3441 
3442     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
3443 
3444     // Maintain fast thread list
3445     ThreadsSMRSupport::remove_thread(p);
3446 
3447     _number_of_threads--;
3448     if (!is_daemon) {
3449       _number_of_non_daemon_threads--;
3450 
3451       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3452       // on destroy_vm will wake up.
3453       if (number_of_non_daemon_threads() == 1) {
3454         ml.notify_all();
3455       }
3456     }
3457     ThreadService::remove_thread(p, is_daemon);
3458 
3459     // Make sure that safepoint code disregard this thread. This is needed since
3460     // the thread might mess around with locks after this point. This can cause it
3461     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3462     // of this thread since it is removed from the queue.
3463     p->set_terminated(JavaThread::_thread_terminated);
3464 
3465     // Notify threads waiting in EscapeBarriers
3466     EscapeBarrier::thread_removed(p);
3467   } // unlock Threads_lock
3468 
3469   // Reduce the ObjectMonitor ceiling for the exiting thread.
3470   ObjectSynchronizer::dec_in_use_list_ceiling();
3471 
3472   // Since Events::log uses a lock, we grab it outside the Threads_lock
3473   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
3474 }
3475 
3476 // Operations on the Threads list for GC.  These are not explicitly locked,
3477 // but the garbage collector must provide a safe context for them to run.
3478 // In particular, these things should never be called when the Threads_lock
3479 // is held by some other thread. (Note: the Safepoint abstraction also
3480 // uses the Threads_lock to guarantee this property. It also makes sure that
3481 // all threads gets blocked when exiting or starting).
3482 
3483 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3484   ALL_JAVA_THREADS(p) {
3485     p->oops_do(f, cf);
3486   }
3487   VMThread::vm_thread()->oops_do(f, cf);
3488 }
3489 
3490 void Threads::change_thread_claim_token() {
3491   if (++_thread_claim_token == 0) {
3492     // On overflow of the token counter, there is a risk of future
3493     // collisions between a new global token value and a stale token
3494     // for a thread, because not all iterations visit all threads.
3495     // (Though it's pretty much a theoretical concern for non-trivial
3496     // token counter sizes.)  To deal with the possibility, reset all
3497     // the thread tokens to zero on global token overflow.
3498     struct ResetClaims : public ThreadClosure {
3499       virtual void do_thread(Thread* t) {
3500         t->claim_threads_do(false, 0);
3501       }
3502     } reset_claims;
3503     Threads::threads_do(&reset_claims);
3504     // On overflow, update the global token to non-zero, to
3505     // avoid the special "never claimed" initial thread value.
3506     _thread_claim_token = 1;
3507   }
3508 }
3509 
3510 #ifdef ASSERT
3511 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
3512   const uintx token = t->threads_do_token();
3513   assert(token == expected,
3514          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
3515          UINTX_FORMAT, kind, p2i(t), token, expected);
3516 }
3517 
3518 void Threads::assert_all_threads_claimed() {
3519   ALL_JAVA_THREADS(p) {
3520     assert_thread_claimed("Thread", p, _thread_claim_token);
3521   }
3522   assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
3523 }
3524 #endif // ASSERT
3525 
3526 class ParallelOopsDoThreadClosure : public ThreadClosure {
3527 private:
3528   OopClosure* _f;
3529   CodeBlobClosure* _cf;
3530 public:
3531   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
3532   void do_thread(Thread* t) {
3533     t->oops_do(_f, _cf);
3534   }
3535 };
3536 
3537 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
3538   ParallelOopsDoThreadClosure tc(f, cf);
3539   possibly_parallel_threads_do(is_par, &tc);
3540 }
3541 
3542 void Threads::metadata_do(MetadataClosure* f) {
3543   ALL_JAVA_THREADS(p) {
3544     p->metadata_do(f);
3545   }
3546 }
3547 
3548 class ThreadHandlesClosure : public ThreadClosure {
3549   void (*_f)(Metadata*);
3550  public:
3551   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
3552   virtual void do_thread(Thread* thread) {
3553     thread->metadata_handles_do(_f);
3554   }
3555 };
3556 
3557 void Threads::metadata_handles_do(void f(Metadata*)) {
3558   // Only walk the Handles in Thread.
3559   ThreadHandlesClosure handles_closure(f);
3560   threads_do(&handles_closure);
3561 }
3562 
3563 // Get count Java threads that are waiting to enter the specified monitor.
3564 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
3565                                                          int count,
3566                                                          address monitor) {
3567   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3568 
3569   int i = 0;
3570   for (JavaThread* p : *t_list) {
3571     if (!p->can_call_java()) continue;
3572 
3573     // The first stage of async deflation does not affect any field
3574     // used by this comparison so the ObjectMonitor* is usable here.
3575     address pending = (address)p->current_pending_monitor();
3576     if (pending == monitor) {             // found a match
3577       if (i < count) result->append(p);   // save the first count matches
3578       i++;
3579     }
3580   }
3581 
3582   return result;
3583 }
3584 
3585 
3586 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
3587                                                       address owner) {
3588   // NULL owner means not locked so we can skip the search
3589   if (owner == NULL) return NULL;
3590 
3591   for (JavaThread* p : *t_list) {
3592     // first, see if owner is the address of a Java thread
3593     if (owner == (address)p) return p;
3594   }
3595 
3596   // Cannot assert on lack of success here since this function may be
3597   // used by code that is trying to report useful problem information
3598   // like deadlock detection.
3599   if (UseHeavyMonitors) return NULL;
3600 
3601   // If we didn't find a matching Java thread and we didn't force use of
3602   // heavyweight monitors, then the owner is the stack address of the
3603   // Lock Word in the owning Java thread's stack.
3604   //
3605   JavaThread* the_owner = NULL;
3606   for (JavaThread* q : *t_list) {
3607     if (q->is_lock_owned(owner)) {
3608       the_owner = q;
3609       break;
3610     }
3611   }
3612 
3613   // cannot assert on lack of success here; see above comment
3614   return the_owner;
3615 }
3616 
3617 class PrintOnClosure : public ThreadClosure {
3618 private:
3619   outputStream* _st;
3620 
3621 public:
3622   PrintOnClosure(outputStream* st) :
3623       _st(st) {}
3624 
3625   virtual void do_thread(Thread* thread) {
3626     if (thread != NULL) {
3627       thread->print_on(_st);
3628       _st->cr();
3629     }
3630   }
3631 };
3632 
3633 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3634 void Threads::print_on(outputStream* st, bool print_stacks,
3635                        bool internal_format, bool print_concurrent_locks,
3636                        bool print_extended_info) {
3637   char buf[32];
3638   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
3639 
3640   st->print_cr("Full thread dump %s (%s %s):",
3641                VM_Version::vm_name(),
3642                VM_Version::vm_release(),
3643                VM_Version::vm_info_string());
3644   st->cr();
3645 
3646 #if INCLUDE_SERVICES
3647   // Dump concurrent locks
3648   ConcurrentLocksDump concurrent_locks;
3649   if (print_concurrent_locks) {
3650     concurrent_locks.dump_at_safepoint();
3651   }
3652 #endif // INCLUDE_SERVICES
3653 
3654   ThreadsSMRSupport::print_info_on(st);
3655   st->cr();
3656 
3657   ALL_JAVA_THREADS(p) {
3658     ResourceMark rm;
3659     p->print_on(st, print_extended_info);
3660     if (print_stacks) {
3661       if (internal_format) {
3662         p->trace_stack();
3663       } else {
3664         p->print_stack_on(st);
3665       }
3666     }
3667     st->cr();
3668 #if INCLUDE_SERVICES
3669     if (print_concurrent_locks) {
3670       concurrent_locks.print_locks_on(p, st);
3671     }
3672 #endif // INCLUDE_SERVICES
3673   }
3674 
3675   PrintOnClosure cl(st);
3676   cl.do_thread(VMThread::vm_thread());
3677   Universe::heap()->gc_threads_do(&cl);
3678   if (StringDedup::is_enabled()) {
3679     StringDedup::threads_do(&cl);
3680   }
3681   cl.do_thread(WatcherThread::watcher_thread());
3682   cl.do_thread(AsyncLogWriter::instance());
3683 
3684   st->flush();
3685 }
3686 
3687 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
3688                              int buflen, bool* found_current) {
3689   if (this_thread != NULL) {
3690     bool is_current = (current == this_thread);
3691     *found_current = *found_current || is_current;
3692     st->print("%s", is_current ? "=>" : "  ");
3693 
3694     st->print(PTR_FORMAT, p2i(this_thread));
3695     st->print(" ");
3696     this_thread->print_on_error(st, buf, buflen);
3697     st->cr();
3698   }
3699 }
3700 
3701 class PrintOnErrorClosure : public ThreadClosure {
3702   outputStream* _st;
3703   Thread* _current;
3704   char* _buf;
3705   int _buflen;
3706   bool* _found_current;
3707  public:
3708   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
3709                       int buflen, bool* found_current) :
3710    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
3711 
3712   virtual void do_thread(Thread* thread) {
3713     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
3714   }
3715 };
3716 
3717 // Threads::print_on_error() is called by fatal error handler. It's possible
3718 // that VM is not at safepoint and/or current thread is inside signal handler.
3719 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3720 // memory (even in resource area), it might deadlock the error handler.
3721 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
3722                              int buflen) {
3723   ThreadsSMRSupport::print_info_on(st);
3724   st->cr();
3725 
3726   bool found_current = false;
3727   st->print_cr("Java Threads: ( => current thread )");
3728   ALL_JAVA_THREADS(thread) {
3729     print_on_error(thread, st, current, buf, buflen, &found_current);
3730   }
3731   st->cr();
3732 
3733   st->print_cr("Other Threads:");
3734   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
3735   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
3736   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
3737 
3738   if (Universe::heap() != NULL) {
3739     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3740     Universe::heap()->gc_threads_do(&print_closure);
3741   }
3742 
3743   if (StringDedup::is_enabled()) {
3744     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3745     StringDedup::threads_do(&print_closure);
3746   }
3747 
3748   if (!found_current) {
3749     st->cr();
3750     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
3751     current->print_on_error(st, buf, buflen);
3752     st->cr();
3753   }
3754   st->cr();
3755 
3756   st->print_cr("Threads with active compile tasks:");
3757   print_threads_compiling(st, buf, buflen);
3758 }
3759 
3760 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
3761   ALL_JAVA_THREADS(thread) {
3762     if (thread->is_Compiler_thread()) {
3763       CompilerThread* ct = (CompilerThread*) thread;
3764 
3765       // Keep task in local variable for NULL check.
3766       // ct->_task might be set to NULL by concurring compiler thread
3767       // because it completed the compilation. The task is never freed,
3768       // though, just returned to a free list.
3769       CompileTask* task = ct->task();
3770       if (task != NULL) {
3771         thread->print_name_on_error(st, buf, buflen);
3772         st->print("  ");
3773         task->print(st, NULL, short_form, true);
3774       }
3775     }
3776   }
3777 }
3778 
3779 
3780 // Ad-hoc mutual exclusion primitives: SpinLock
3781 //
3782 // We employ SpinLocks _only for low-contention, fixed-length
3783 // short-duration critical sections where we're concerned
3784 // about native mutex_t or HotSpot Mutex:: latency.
3785 //
3786 // TODO-FIXME: ListLock should be of type SpinLock.
3787 // We should make this a 1st-class type, integrated into the lock
3788 // hierarchy as leaf-locks.  Critically, the SpinLock structure
3789 // should have sufficient padding to avoid false-sharing and excessive
3790 // cache-coherency traffic.
3791 
3792 
3793 typedef volatile int SpinLockT;
3794 
3795 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
3796   if (Atomic::cmpxchg(adr, 0, 1) == 0) {
3797     return;   // normal fast-path return
3798   }
3799 
3800   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
3801   int ctr = 0;
3802   int Yields = 0;
3803   for (;;) {
3804     while (*adr != 0) {
3805       ++ctr;
3806       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
3807         if (Yields > 5) {
3808           os::naked_short_sleep(1);
3809         } else {
3810           os::naked_yield();
3811           ++Yields;
3812         }
3813       } else {
3814         SpinPause();
3815       }
3816     }
3817     if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
3818   }
3819 }
3820 
3821 void Thread::SpinRelease(volatile int * adr) {
3822   assert(*adr != 0, "invariant");
3823   OrderAccess::fence();      // guarantee at least release consistency.
3824   // Roach-motel semantics.
3825   // It's safe if subsequent LDs and STs float "up" into the critical section,
3826   // but prior LDs and STs within the critical section can't be allowed
3827   // to reorder or float past the ST that releases the lock.
3828   // Loads and stores in the critical section - which appear in program
3829   // order before the store that releases the lock - must also appear
3830   // before the store that releases the lock in memory visibility order.
3831   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
3832   // the ST of 0 into the lock-word which releases the lock, so fence
3833   // more than covers this on all platforms.
3834   *adr = 0;
3835 }
3836 
3837 
3838 void Threads::verify() {
3839   ALL_JAVA_THREADS(p) {
3840     p->verify();
3841   }
3842   VMThread* thread = VMThread::vm_thread();
3843   if (thread != NULL) thread->verify();
3844 }
3845 
3846 #ifndef PRODUCT
3847 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
3848    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
3849 }
3850 #endif
3851 
3852 // Helper function to create the java.lang.Thread object for a
3853 // VM-internal thread. The thread will have the given name, be
3854 // part of the System ThreadGroup and if is_visible is true will be
3855 // discoverable via the system ThreadGroup.
3856 Handle JavaThread::create_system_thread_object(const char* name,
3857                                                bool is_visible, TRAPS) {
3858   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
3859 
3860   // Initialize thread_oop to put it into the system threadGroup.
3861   // This is done by calling the Thread(ThreadGroup tg, String name)
3862   // constructor, which adds the new thread to the group as an unstarted
3863   // thread.
3864   Handle thread_group(THREAD, Universe::system_thread_group());
3865   Handle thread_oop =
3866     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
3867                                       vmSymbols::threadgroup_string_void_signature(),
3868                                       thread_group,
3869                                       string,
3870                                       CHECK_NH);
3871 
3872   // If the Thread is intended to be visible then we have to mimic what
3873   // Thread.start() would do, by adding it to its ThreadGroup: tg.add(t).
3874   if (is_visible) {
3875     Klass* group = vmClasses::ThreadGroup_klass();
3876     JavaValue result(T_VOID);
3877     JavaCalls::call_special(&result,
3878                             thread_group,
3879                             group,
3880                             vmSymbols::add_method_name(),
3881                             vmSymbols::thread_void_signature(),
3882                             thread_oop,
3883                             CHECK_NH);
3884   }
3885 
3886   return thread_oop;
3887 }
3888 
3889 // Starts the target JavaThread as a daemon of the given priority, and
3890 // bound to the given java.lang.Thread instance.
3891 // The Threads_lock is held for the duration.
3892 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
3893                                        Handle thread_oop, ThreadPriority prio) {
3894 
3895   assert(target->osthread() != NULL, "target thread is not properly initialized");
3896 
3897   MutexLocker mu(current, Threads_lock);
3898 
3899   // Initialize the fields of the thread_oop first.
3900 
3901   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
3902 
3903   if (prio != NoPriority) {
3904     java_lang_Thread::set_priority(thread_oop(), prio);
3905     // Note: we don't call os::set_priority here. Possibly we should,
3906     // else all threads should call it themselves when they first run.
3907   }
3908 
3909   java_lang_Thread::set_daemon(thread_oop());
3910 
3911   // Now bind the thread_oop to the target JavaThread.
3912   target->set_threadObj(thread_oop());
3913 
3914   Threads::add(target); // target is now visible for safepoint/handshake
3915   Thread::start(target);
3916 }
3917 
3918 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
3919   // At this point it may be possible that no osthread was created for the
3920   // JavaThread due to lack of resources. However, since this must work
3921   // for critical system threads just check and abort if this fails.
3922   if (thread->osthread() == nullptr) {
3923     // This isn't really an OOM condition, but historically this is what
3924     // we report.
3925     vm_exit_during_initialization("java.lang.OutOfMemoryError",
3926                                   os::native_thread_creation_failed_msg());
3927   }
3928 }