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/heapObjectStatistics.hpp"
 121 #include "services/management.hpp"
 122 #include "services/memTracker.hpp"
 123 #include "services/threadService.hpp"
 124 #include "utilities/align.hpp"
 125 #include "utilities/copy.hpp"
 126 #include "utilities/defaultStream.hpp"
 127 #include "utilities/dtrace.hpp"
 128 #include "utilities/events.hpp"
 129 #include "utilities/macros.hpp"
 130 #include "utilities/preserveException.hpp"
 131 #include "utilities/spinYield.hpp"
 132 #include "utilities/vmError.hpp"
 133 #if INCLUDE_JVMCI
 134 #include "jvmci/jvmci.hpp"
 135 #include "jvmci/jvmciEnv.hpp"
 136 #endif
 137 #ifdef COMPILER1
 138 #include "c1/c1_Compiler.hpp"
 139 #endif
 140 #ifdef COMPILER2
 141 #include "opto/c2compiler.hpp"
 142 #include "opto/idealGraphPrinter.hpp"
 143 #endif
 144 #if INCLUDE_RTM_OPT
 145 #include "runtime/rtmLocking.hpp"
 146 #endif
 147 #if INCLUDE_JFR
 148 #include "jfr/jfr.hpp"
 149 #endif
 150 
 151 // Initialization after module runtime initialization
 152 void universe_post_module_init();  // must happen after call_initPhase2
 153 
 154 #ifdef DTRACE_ENABLED
 155 
 156 // Only bother with this argument setup if dtrace is available
 157 
 158   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 159   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 160 
 161   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 162     {                                                                      \
 163       ResourceMark rm(this);                                               \
 164       int len = 0;                                                         \
 165       const char* name = (javathread)->name();                             \
 166       len = strlen(name);                                                  \
 167       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 168         (char *) name, len,                                                \
 169         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 170         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 171         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 172     }
 173 
 174 #else //  ndef DTRACE_ENABLED
 175 
 176   #define DTRACE_THREAD_PROBE(probe, javathread)
 177 
 178 #endif // ndef DTRACE_ENABLED
 179 
 180 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 181 // Current thread is maintained as a thread-local variable
 182 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
 183 #endif
 184 
 185 // ======= Thread ========
 186 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 187   return throw_excpt ? AllocateHeap(size, flags, CURRENT_PC)
 188                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 189 }
 190 
 191 void Thread::operator delete(void* p) {
 192   FreeHeap(p);
 193 }
 194 
 195 void JavaThread::smr_delete() {
 196   if (_on_thread_list) {
 197     ThreadsSMRSupport::smr_delete(this);
 198   } else {
 199     delete this;
 200   }
 201 }
 202 
 203 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 204 // JavaThread
 205 
 206 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
 207 
 208 Thread::Thread() {
 209 
 210   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 211 
 212   // stack and get_thread
 213   set_stack_base(NULL);
 214   set_stack_size(0);
 215   set_lgrp_id(-1);
 216   DEBUG_ONLY(clear_suspendible_thread();)
 217 
 218   // allocated data structures
 219   set_osthread(NULL);
 220   set_resource_area(new (mtThread)ResourceArea());
 221   DEBUG_ONLY(_current_resource_mark = NULL;)
 222   set_handle_area(new (mtThread) HandleArea(NULL));
 223   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
 224   set_last_handle_mark(NULL);
 225   DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
 226 
 227   // Initial value of zero ==> never claimed.
 228   _threads_do_token = 0;
 229   _threads_hazard_ptr = NULL;
 230   _threads_list_ptr = NULL;
 231   _nested_threads_hazard_ptr_cnt = 0;
 232   _rcu_counter = 0;
 233 
 234   // the handle mark links itself to last_handle_mark
 235   new HandleMark(this);
 236 
 237   // plain initialization
 238   debug_only(_owned_locks = NULL;)
 239   NOT_PRODUCT(_skip_gcalot = false;)
 240   _jvmti_env_iteration_count = 0;
 241   set_allocated_bytes(0);
 242   _current_pending_raw_monitor = NULL;
 243 
 244   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 245   _hashStateX = os::random();
 246   _hashStateY = 842502087;
 247   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 248   _hashStateW = 273326509;
 249 
 250   // Many of the following fields are effectively final - immutable
 251   // Note that nascent threads can't use the Native Monitor-Mutex
 252   // construct until the _MutexEvent is initialized ...
 253   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 254   // we might instead use a stack of ParkEvents that we could provision on-demand.
 255   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 256   // and ::Release()
 257   _ParkEvent   = ParkEvent::Allocate(this);
 258 
 259 #ifdef CHECK_UNHANDLED_OOPS
 260   if (CheckUnhandledOops) {
 261     _unhandled_oops = new UnhandledOops(this);
 262   }
 263 #endif // CHECK_UNHANDLED_OOPS
 264 
 265   // Notify the barrier set that a thread is being created. The initial
 266   // thread is created before the barrier set is available.  The call to
 267   // BarrierSet::on_thread_create() for this thread is therefore deferred
 268   // to BarrierSet::set_barrier_set().
 269   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 270   if (barrier_set != NULL) {
 271     barrier_set->on_thread_create(this);
 272   } else {
 273     // Only the main thread should be created before the barrier set
 274     // and that happens just before Thread::current is set. No other thread
 275     // can attach as the VM is not created yet, so they can't execute this code.
 276     // If the main thread creates other threads before the barrier set that is an error.
 277     assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
 278   }
 279 
 280   MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
 281 }
 282 
 283 void Thread::initialize_tlab() {
 284   if (UseTLAB) {
 285     tlab().initialize();
 286   }
 287 }
 288 
 289 void Thread::initialize_thread_current() {
 290 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 291   assert(_thr_current == NULL, "Thread::current already initialized");
 292   _thr_current = this;
 293 #endif
 294   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 295   ThreadLocalStorage::set_thread(this);
 296   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 297 }
 298 
 299 void Thread::clear_thread_current() {
 300   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 301 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 302   _thr_current = NULL;
 303 #endif
 304   ThreadLocalStorage::set_thread(NULL);
 305 }
 306 
 307 void Thread::record_stack_base_and_size() {
 308   // Note: at this point, Thread object is not yet initialized. Do not rely on
 309   // any members being initialized. Do not rely on Thread::current() being set.
 310   // If possible, refrain from doing anything which may crash or assert since
 311   // quite probably those crash dumps will be useless.
 312   set_stack_base(os::current_stack_base());
 313   set_stack_size(os::current_stack_size());
 314 
 315   // Set stack limits after thread is initialized.
 316   if (is_Java_thread()) {
 317     JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
 318   }
 319 }
 320 
 321 void Thread::register_thread_stack_with_NMT() {
 322   MemTracker::record_thread_stack(stack_end(), stack_size());
 323 }
 324 
 325 void Thread::unregister_thread_stack_with_NMT() {
 326   MemTracker::release_thread_stack(stack_end(), stack_size());
 327 }
 328 
 329 void Thread::call_run() {
 330   DEBUG_ONLY(_run_state = CALL_RUN;)
 331 
 332   // At this point, Thread object should be fully initialized and
 333   // Thread::current() should be set.
 334 
 335   assert(Thread::current_or_null() != NULL, "current thread is unset");
 336   assert(Thread::current_or_null() == this, "current thread is wrong");
 337 
 338   // Perform common initialization actions
 339 
 340   MACOS_AARCH64_ONLY(this->init_wx());
 341 
 342   register_thread_stack_with_NMT();
 343 
 344   JFR_ONLY(Jfr::on_thread_start(this);)
 345 
 346   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 347     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 348     os::current_thread_id(), p2i(stack_end()),
 349     p2i(stack_base()), stack_size()/1024);
 350 
 351   // Perform <ChildClass> initialization actions
 352   DEBUG_ONLY(_run_state = PRE_RUN;)
 353   this->pre_run();
 354 
 355   // Invoke <ChildClass>::run()
 356   DEBUG_ONLY(_run_state = RUN;)
 357   this->run();
 358   // Returned from <ChildClass>::run(). Thread finished.
 359 
 360   // Perform common tear-down actions
 361 
 362   assert(Thread::current_or_null() != NULL, "current thread is unset");
 363   assert(Thread::current_or_null() == this, "current thread is wrong");
 364 
 365   // Perform <ChildClass> tear-down actions
 366   DEBUG_ONLY(_run_state = POST_RUN;)
 367   this->post_run();
 368 
 369   // Note: at this point the thread object may already have deleted itself,
 370   // so from here on do not dereference *this*. Not all thread types currently
 371   // delete themselves when they terminate. But no thread should ever be deleted
 372   // asynchronously with respect to its termination - that is what _run_state can
 373   // be used to check.
 374 
 375   assert(Thread::current_or_null() == NULL, "current thread still present");
 376 }
 377 
 378 Thread::~Thread() {
 379 
 380   // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
 381   // get started due to errors etc. Any active thread should at least reach post_run
 382   // before it is deleted (usually in post_run()).
 383   assert(_run_state == PRE_CALL_RUN ||
 384          _run_state == POST_RUN, "Active Thread deleted before post_run(): "
 385          "_run_state=%d", (int)_run_state);
 386 
 387   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 388   // set might not be available if we encountered errors during bootstrapping.
 389   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 390   if (barrier_set != NULL) {
 391     barrier_set->on_thread_destroy(this);
 392   }
 393 
 394   // deallocate data structures
 395   delete resource_area();
 396   // since the handle marks are using the handle area, we have to deallocated the root
 397   // handle mark before deallocating the thread's handle area,
 398   assert(last_handle_mark() != NULL, "check we have an element");
 399   delete last_handle_mark();
 400   assert(last_handle_mark() == NULL, "check we have reached the end");
 401 
 402   ParkEvent::Release(_ParkEvent);
 403   // Set to NULL as a termination indicator for has_terminated().
 404   Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
 405 
 406   delete handle_area();
 407   delete metadata_handles();
 408 
 409   // osthread() can be NULL, if creation of thread failed.
 410   if (osthread() != NULL) os::free_thread(osthread());
 411 
 412   // Clear Thread::current if thread is deleting itself and it has not
 413   // already been done. This must be done before the memory is deallocated.
 414   // Needed to ensure JNI correctly detects non-attached threads.
 415   if (this == Thread::current_or_null()) {
 416     Thread::clear_thread_current();
 417   }
 418 
 419   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 420 }
 421 
 422 #ifdef ASSERT
 423 // A JavaThread is considered dangling if it not handshake-safe with respect to
 424 // the current thread, it is not on a ThreadsList, or not at safepoint.
 425 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 426   assert(!thread->is_Java_thread() ||
 427          JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
 428          !JavaThread::cast(thread)->on_thread_list() ||
 429          SafepointSynchronize::is_at_safepoint() ||
 430          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
 431          "possibility of dangling Thread pointer");
 432 }
 433 #endif
 434 
 435 // Is the target JavaThread protected by the calling Thread or by some other
 436 // mechanism?
 437 //
 438 bool Thread::is_JavaThread_protected(const JavaThread* target) {
 439   Thread* current_thread = Thread::current();
 440 
 441   // Do the simplest check first:
 442   if (SafepointSynchronize::is_at_safepoint()) {
 443     // The target is protected since JavaThreads cannot exit
 444     // while we're at a safepoint.
 445     return true;
 446   }
 447 
 448   // If the target hasn't been started yet then it is trivially
 449   // "protected". We assume the caller is the thread that will do
 450   // the starting.
 451   if (target->osthread() == NULL || target->osthread()->get_state() <= INITIALIZED) {
 452     return true;
 453   }
 454 
 455   // Now make the simple checks based on who the caller is:
 456   if (current_thread == target || Threads_lock->owner() == current_thread) {
 457     // Target JavaThread is self or calling thread owns the Threads_lock.
 458     // Second check is the same as Threads_lock->owner_is_self(),
 459     // but we already have the current thread so check directly.
 460     return true;
 461   }
 462 
 463   // Check the ThreadsLists associated with the calling thread (if any)
 464   // to see if one of them protects the target JavaThread:
 465   if (is_JavaThread_protected_by_TLH(target)) {
 466     return true;
 467   }
 468 
 469   // Use this debug code with -XX:+UseNewCode to diagnose locations that
 470   // are missing a ThreadsListHandle or other protection mechanism:
 471   // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting target="
 472   //           INTPTR_FORMAT, p2i(current_thread), p2i(target));
 473 
 474   // Note: Since 'target' isn't protected by a TLH, the call to
 475   // target->is_handshake_safe_for() may crash, but we have debug bits so
 476   // we'll be able to figure out what protection mechanism is missing.
 477   assert(target->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
 478          " is not protected and not handshake safe.", p2i(target));
 479 
 480   // The target JavaThread is not protected so it is not safe to query:
 481   return false;
 482 }
 483 
 484 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
 485 // with the calling Thread?
 486 //
 487 bool Thread::is_JavaThread_protected_by_TLH(const JavaThread* target) {
 488   Thread* current_thread = Thread::current();
 489 
 490   // Check the ThreadsLists associated with the calling thread (if any)
 491   // to see if one of them protects the target JavaThread:
 492   for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
 493        stlp != NULL; stlp = stlp->previous()) {
 494     if (stlp->list()->includes(target)) {
 495       // The target JavaThread is protected by this ThreadsList:
 496       return true;
 497     }
 498   }
 499 
 500   // The target JavaThread is not protected by a TLH so it is not safe to query:
 501   return false;
 502 }
 503 
 504 ThreadPriority Thread::get_priority(const Thread* const thread) {
 505   ThreadPriority priority;
 506   // Can return an error!
 507   (void)os::get_priority(thread, priority);
 508   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 509   return priority;
 510 }
 511 
 512 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 513   debug_only(check_for_dangling_thread_pointer(thread);)
 514   // Can return an error!
 515   (void)os::set_priority(thread, priority);
 516 }
 517 
 518 
 519 void Thread::start(Thread* thread) {
 520   // Start is different from resume in that its safety is guaranteed by context or
 521   // being called from a Java method synchronized on the Thread object.
 522   if (thread->is_Java_thread()) {
 523     // Initialize the thread state to RUNNABLE before starting this thread.
 524     // Can not set it after the thread started because we do not know the
 525     // exact thread state at that time. It could be in MONITOR_WAIT or
 526     // in SLEEPING or some other state.
 527     java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
 528                                         JavaThreadStatus::RUNNABLE);
 529   }
 530   os::start_thread(thread);
 531 }
 532 
 533 // GC Support
 534 bool Thread::claim_par_threads_do(uintx claim_token) {
 535   uintx token = _threads_do_token;
 536   if (token != claim_token) {
 537     uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
 538     if (res == token) {
 539       return true;
 540     }
 541     guarantee(res == claim_token, "invariant");
 542   }
 543   return false;
 544 }
 545 
 546 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
 547   // Do oop for ThreadShadow
 548   f->do_oop((oop*)&_pending_exception);
 549   handle_area()->oops_do(f);
 550 }
 551 
 552 // If the caller is a NamedThread, then remember, in the current scope,
 553 // the given JavaThread in its _processed_thread field.
 554 class RememberProcessedThread: public StackObj {
 555   NamedThread* _cur_thr;
 556 public:
 557   RememberProcessedThread(Thread* thread) {
 558     Thread* self = Thread::current();
 559     if (self->is_Named_thread()) {
 560       _cur_thr = (NamedThread *)self;
 561       assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
 562       _cur_thr->set_processed_thread(thread);
 563     } else {
 564       _cur_thr = NULL;
 565     }
 566   }
 567 
 568   ~RememberProcessedThread() {
 569     if (_cur_thr) {
 570       assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
 571       _cur_thr->set_processed_thread(NULL);
 572     }
 573   }
 574 };
 575 
 576 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 577   // Record JavaThread to GC thread
 578   RememberProcessedThread rpt(this);
 579   oops_do_no_frames(f, cf);
 580   oops_do_frames(f, cf);
 581 }
 582 
 583 void Thread::metadata_handles_do(void f(Metadata*)) {
 584   // Only walk the Handles in Thread.
 585   if (metadata_handles() != NULL) {
 586     for (int i = 0; i< metadata_handles()->length(); i++) {
 587       f(metadata_handles()->at(i));
 588     }
 589   }
 590 }
 591 
 592 void Thread::print_on(outputStream* st, bool print_extended_info) const {
 593   // get_priority assumes osthread initialized
 594   if (osthread() != NULL) {
 595     int os_prio;
 596     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 597       st->print("os_prio=%d ", os_prio);
 598     }
 599 
 600     st->print("cpu=%.2fms ",
 601               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 602               );
 603     st->print("elapsed=%.2fs ",
 604               _statistical_info.getElapsedTime() / 1000.0
 605               );
 606     if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
 607       size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
 608       st->print("allocated=" SIZE_FORMAT "%s ",
 609                 byte_size_in_proper_unit(allocated_bytes),
 610                 proper_unit_for_byte_size(allocated_bytes)
 611                 );
 612       st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
 613     }
 614 
 615     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 616     osthread()->print_on(st);
 617   }
 618   ThreadsSMRSupport::print_info_on(this, st);
 619   st->print(" ");
 620   debug_only(if (WizardMode) print_owned_locks_on(st);)
 621 }
 622 
 623 void Thread::print() const { print_on(tty); }
 624 
 625 // Thread::print_on_error() is called by fatal error handler. Don't use
 626 // any lock or allocate memory.
 627 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 628   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 629 
 630   st->print("%s \"%s\"", type_name(), name());
 631 
 632   OSThread* os_thr = osthread();
 633   if (os_thr != NULL) {
 634     if (os_thr->get_state() != ZOMBIE) {
 635       st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 636                 p2i(stack_end()), p2i(stack_base()));
 637       st->print(" [id=%d]", osthread()->thread_id());
 638     } else {
 639       st->print(" terminated");
 640     }
 641   } else {
 642     st->print(" unknown state (no osThread)");
 643   }
 644   ThreadsSMRSupport::print_info_on(this, st);
 645 }
 646 
 647 void Thread::print_value_on(outputStream* st) const {
 648   if (is_Named_thread()) {
 649     st->print(" \"%s\" ", name());
 650   }
 651   st->print(INTPTR_FORMAT, p2i(this));   // print address
 652 }
 653 
 654 #ifdef ASSERT
 655 void Thread::print_owned_locks_on(outputStream* st) const {
 656   Mutex* cur = _owned_locks;
 657   if (cur == NULL) {
 658     st->print(" (no locks) ");
 659   } else {
 660     st->print_cr(" Locks owned:");
 661     while (cur) {
 662       cur->print_on(st);
 663       cur = cur->next();
 664     }
 665   }
 666 }
 667 #endif // ASSERT
 668 
 669 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 670 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 671 // used for compilation in the future. If that change is made, the need for these methods
 672 // should be revisited, and they should be removed if possible.
 673 
 674 bool Thread::is_lock_owned(address adr) const {
 675   return is_in_full_stack(adr);
 676 }
 677 
 678 bool Thread::set_as_starting_thread() {
 679   assert(_starting_thread == NULL, "already initialized: "
 680          "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
 681   // NOTE: this must be called inside the main thread.
 682   DEBUG_ONLY(_starting_thread = this;)
 683   return os::create_main_thread(JavaThread::cast(this));
 684 }
 685 
 686 static void initialize_class(Symbol* class_name, TRAPS) {
 687   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 688   InstanceKlass::cast(klass)->initialize(CHECK);
 689 }
 690 
 691 
 692 // Creates the initial ThreadGroup
 693 static Handle create_initial_thread_group(TRAPS) {
 694   Handle system_instance = JavaCalls::construct_new_instance(
 695                             vmClasses::ThreadGroup_klass(),
 696                             vmSymbols::void_method_signature(),
 697                             CHECK_NH);
 698   Universe::set_system_thread_group(system_instance());
 699 
 700   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 701   Handle main_instance = JavaCalls::construct_new_instance(
 702                             vmClasses::ThreadGroup_klass(),
 703                             vmSymbols::threadgroup_string_void_signature(),
 704                             system_instance,
 705                             string,
 706                             CHECK_NH);
 707   return main_instance;
 708 }
 709 
 710 // Creates the initial Thread, and sets it to running.
 711 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 712                                  TRAPS) {
 713   InstanceKlass* ik = vmClasses::Thread_klass();
 714   assert(ik->is_initialized(), "must be");
 715   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 716 
 717   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 718   // constructor calls Thread.current(), which must be set here for the
 719   // initial thread.
 720   java_lang_Thread::set_thread(thread_oop(), thread);
 721   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 722   thread->set_threadObj(thread_oop());
 723 
 724   Handle string = java_lang_String::create_from_str("main", CHECK);
 725 
 726   JavaValue result(T_VOID);
 727   JavaCalls::call_special(&result, thread_oop,
 728                           ik,
 729                           vmSymbols::object_initializer_name(),
 730                           vmSymbols::threadgroup_string_void_signature(),
 731                           thread_group,
 732                           string,
 733                           CHECK);
 734 
 735   // Set thread status to running since main thread has
 736   // been started and running.
 737   java_lang_Thread::set_thread_status(thread_oop(),
 738                                       JavaThreadStatus::RUNNABLE);
 739 }
 740 
 741 // Extract version and vendor specific information from
 742 // java.lang.VersionProps fields.
 743 // Returned char* is allocated in the thread's resource area
 744 // so must be copied for permanency.
 745 static const char* get_java_version_info(InstanceKlass* ik,
 746                                          Symbol* field_name) {
 747   fieldDescriptor fd;
 748   bool found = ik != NULL &&
 749                ik->find_local_field(field_name,
 750                                     vmSymbols::string_signature(), &fd);
 751   if (found) {
 752     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 753     if (name_oop == NULL) {
 754       return NULL;
 755     }
 756     const char* name = java_lang_String::as_utf8_string(name_oop);
 757     return name;
 758   } else {
 759     return NULL;
 760   }
 761 }
 762 
 763 // General purpose hook into Java code, run once when the VM is initialized.
 764 // The Java library method itself may be changed independently from the VM.
 765 static void call_postVMInitHook(TRAPS) {
 766   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 767   if (klass != NULL) {
 768     JavaValue result(T_VOID);
 769     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 770                            vmSymbols::void_method_signature(),
 771                            CHECK);
 772   }
 773 }
 774 
 775 // Initialized by VMThread at vm_global_init
 776 static OopStorage* _thread_oop_storage = NULL;
 777 
 778 oop  JavaThread::threadObj() const    {
 779   return _threadObj.resolve();
 780 }
 781 
 782 void JavaThread::set_threadObj(oop p) {
 783   assert(_thread_oop_storage != NULL, "not yet initialized");
 784   _threadObj = OopHandle(_thread_oop_storage, p);
 785 }
 786 
 787 OopStorage* JavaThread::thread_oop_storage() {
 788   assert(_thread_oop_storage != NULL, "not yet initialized");
 789   return _thread_oop_storage;
 790 }
 791 
 792 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 793                                     bool daemon, TRAPS) {
 794   assert(thread_group.not_null(), "thread group should be specified");
 795   assert(threadObj() == NULL, "should only create Java thread object once");
 796 
 797   InstanceKlass* ik = vmClasses::Thread_klass();
 798   assert(ik->is_initialized(), "must be");
 799   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 800 
 801   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 802   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 803   // constructor calls Thread.current(), which must be set here.
 804   java_lang_Thread::set_thread(thread_oop(), this);
 805   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 806   set_threadObj(thread_oop());
 807 
 808   JavaValue result(T_VOID);
 809   if (thread_name != NULL) {
 810     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 811     // Thread gets assigned specified name and null target
 812     JavaCalls::call_special(&result,
 813                             thread_oop,
 814                             ik,
 815                             vmSymbols::object_initializer_name(),
 816                             vmSymbols::threadgroup_string_void_signature(),
 817                             thread_group,
 818                             name,
 819                             THREAD);
 820   } else {
 821     // Thread gets assigned name "Thread-nnn" and null target
 822     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 823     JavaCalls::call_special(&result,
 824                             thread_oop,
 825                             ik,
 826                             vmSymbols::object_initializer_name(),
 827                             vmSymbols::threadgroup_runnable_void_signature(),
 828                             thread_group,
 829                             Handle(),
 830                             THREAD);
 831   }
 832 
 833 
 834   if (daemon) {
 835     java_lang_Thread::set_daemon(thread_oop());
 836   }
 837 
 838   if (HAS_PENDING_EXCEPTION) {
 839     return;
 840   }
 841 
 842   Klass* group = vmClasses::ThreadGroup_klass();
 843   Handle threadObj(THREAD, this->threadObj());
 844 
 845   JavaCalls::call_special(&result,
 846                           thread_group,
 847                           group,
 848                           vmSymbols::add_method_name(),
 849                           vmSymbols::thread_void_signature(),
 850                           threadObj,          // Arg 1
 851                           THREAD);
 852 }
 853 
 854 // ======= JavaThread ========
 855 
 856 #if INCLUDE_JVMCI
 857 
 858 jlong* JavaThread::_jvmci_old_thread_counters;
 859 
 860 bool jvmci_counters_include(JavaThread* thread) {
 861   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 862 }
 863 
 864 void JavaThread::collect_counters(jlong* array, int length) {
 865   assert(length == JVMCICounterSize, "wrong value");
 866   for (int i = 0; i < length; i++) {
 867     array[i] = _jvmci_old_thread_counters[i];
 868   }
 869   for (JavaThread* tp : ThreadsListHandle()) {
 870     if (jvmci_counters_include(tp)) {
 871       for (int i = 0; i < length; i++) {
 872         array[i] += tp->_jvmci_counters[i];
 873       }
 874     }
 875   }
 876 }
 877 
 878 // Attempt to enlarge the array for per thread counters.
 879 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 880   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 881   if (new_counters == NULL) {
 882     return NULL;
 883   }
 884   if (old_counters == NULL) {
 885     old_counters = new_counters;
 886     memset(old_counters, 0, sizeof(jlong) * new_size);
 887   } else {
 888     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 889       new_counters[i] = old_counters[i];
 890     }
 891     if (new_size > current_size) {
 892       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 893     }
 894     FREE_C_HEAP_ARRAY(jlong, old_counters);
 895   }
 896   return new_counters;
 897 }
 898 
 899 // Attempt to enlarge the array for per thread counters.
 900 bool JavaThread::resize_counters(int current_size, int new_size) {
 901   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 902   if (new_counters == NULL) {
 903     return false;
 904   } else {
 905     _jvmci_counters = new_counters;
 906     return true;
 907   }
 908 }
 909 
 910 class VM_JVMCIResizeCounters : public VM_Operation {
 911  private:
 912   int _new_size;
 913   bool _failed;
 914 
 915  public:
 916   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 917   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 918   bool allow_nested_vm_operations() const        { return true; }
 919   void doit() {
 920     // Resize the old thread counters array
 921     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 922     if (new_counters == NULL) {
 923       _failed = true;
 924       return;
 925     } else {
 926       JavaThread::_jvmci_old_thread_counters = new_counters;
 927     }
 928 
 929     // Now resize each threads array
 930     for (JavaThread* tp : ThreadsListHandle()) {
 931       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 932         _failed = true;
 933         break;
 934       }
 935     }
 936     if (!_failed) {
 937       JVMCICounterSize = _new_size;
 938     }
 939   }
 940 
 941   bool failed() { return _failed; }
 942 };
 943 
 944 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 945   VM_JVMCIResizeCounters op(new_size);
 946   VMThread::execute(&op);
 947   return !op.failed();
 948 }
 949 
 950 #endif // INCLUDE_JVMCI
 951 
 952 #ifdef ASSERT
 953 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 954 void JavaThread::check_possible_safepoint() {
 955   if (_no_safepoint_count > 0) {
 956     print_owned_locks();
 957     assert(false, "Possible safepoint reached by thread that does not allow it");
 958   }
 959 #ifdef CHECK_UNHANDLED_OOPS
 960   // Clear unhandled oops in JavaThreads so we get a crash right away.
 961   clear_unhandled_oops();
 962 #endif // CHECK_UNHANDLED_OOPS
 963 
 964   // Macos/aarch64 should be in the right state for safepoint (e.g.
 965   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 966   // happens in practice, making such issues hard to find and reproduce.
 967 #if defined(__APPLE__) && defined(AARCH64)
 968   if (AssertWXAtThreadSync) {
 969     assert_wx_state(WXWrite);
 970   }
 971 #endif
 972 }
 973 
 974 void JavaThread::check_for_valid_safepoint_state() {
 975   // Check NoSafepointVerifier, which is implied by locks taken that can be
 976   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 977   // are held.
 978   check_possible_safepoint();
 979 
 980   if (thread_state() != _thread_in_vm) {
 981     fatal("LEAF method calling lock?");
 982   }
 983 
 984   if (GCALotAtAllSafepoints) {
 985     // We could enter a safepoint here and thus have a gc
 986     InterfaceSupport::check_gc_alot();
 987   }
 988 }
 989 #endif // ASSERT
 990 
 991 // A JavaThread is a normal Java thread
 992 
 993 JavaThread::JavaThread() :
 994   // Initialize fields
 995 
 996   _on_thread_list(false),
 997   DEBUG_ONLY(_java_call_counter(0) COMMA)
 998   _entry_point(nullptr),
 999   _deopt_mark(nullptr),
1000   _deopt_nmethod(nullptr),
1001   _vframe_array_head(nullptr),
1002   _vframe_array_last(nullptr),
1003   _jvmti_deferred_updates(nullptr),
1004   _callee_target(nullptr),
1005   _vm_result(nullptr),
1006   _vm_result_2(nullptr),
1007 
1008   _current_pending_monitor(NULL),
1009   _current_pending_monitor_is_from_java(true),
1010   _current_waiting_monitor(NULL),
1011   _active_handles(NULL),
1012   _free_handle_block(NULL),
1013   _Stalled(0),
1014 
1015   _monitor_chunks(nullptr),
1016 
1017   _suspend_flags(0),
1018 
1019   _thread_state(_thread_new),
1020   _saved_exception_pc(nullptr),
1021 #ifdef ASSERT
1022   _no_safepoint_count(0),
1023   _visited_for_critical_count(false),
1024 #endif
1025 
1026   _terminated(_not_terminated),
1027   _in_deopt_handler(0),
1028   _doing_unsafe_access(false),
1029   _do_not_unlock_if_synchronized(false),
1030   _jni_attach_state(_not_attaching_via_jni),
1031 #if INCLUDE_JVMCI
1032   _pending_deoptimization(-1),
1033   _pending_monitorenter(false),
1034   _pending_transfer_to_interpreter(false),
1035   _in_retryable_allocation(false),
1036   _pending_failed_speculation(0),
1037   _jvmci{nullptr},
1038   _libjvmci_runtime(nullptr),
1039   _jvmci_counters(nullptr),
1040   _jvmci_reserved0(0),
1041   _jvmci_reserved1(0),
1042   _jvmci_reserved_oop0(nullptr),
1043 #endif // INCLUDE_JVMCI
1044 
1045   _exception_oop(oop()),
1046   _exception_pc(0),
1047   _exception_handler_pc(0),
1048   _is_method_handle_return(0),
1049 
1050   _jni_active_critical(0),
1051   _pending_jni_exception_check_fn(nullptr),
1052   _depth_first_number(0),
1053 
1054   // JVMTI PopFrame support
1055   _popframe_condition(popframe_inactive),
1056   _frames_to_pop_failed_realloc(0),
1057 
1058   _handshake(this),
1059 
1060   _popframe_preserved_args(nullptr),
1061   _popframe_preserved_args_size(0),
1062 
1063   _jvmti_thread_state(nullptr),
1064   _interp_only_mode(0),
1065   _should_post_on_exceptions_flag(JNI_FALSE),
1066   _thread_stat(new ThreadStatistics()),
1067 
1068   _parker(),
1069 
1070   _class_to_be_initialized(nullptr),
1071 
1072   _SleepEvent(ParkEvent::Allocate(this))
1073 {
1074   set_jni_functions(jni_functions());
1075 
1076 #if INCLUDE_JVMCI
1077   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
1078   if (JVMCICounterSize > 0) {
1079     resize_counters(0, (int) JVMCICounterSize);
1080   }
1081 #endif // INCLUDE_JVMCI
1082 
1083   // Setup safepoint state info for this thread
1084   ThreadSafepointState::create(this);
1085 
1086   SafepointMechanism::initialize_header(this);
1087 
1088   set_requires_cross_modify_fence(false);
1089 
1090   pd_initialize();
1091   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1092 }
1093 
1094 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
1095   if (is_attaching_via_jni) {
1096     _jni_attach_state = _attaching_via_jni;
1097   }
1098 }
1099 
1100 
1101 // interrupt support
1102 
1103 void JavaThread::interrupt() {
1104   // All callers should have 'this' thread protected by a
1105   // ThreadsListHandle so that it cannot terminate and deallocate
1106   // itself.
1107   debug_only(check_for_dangling_thread_pointer(this);)
1108 
1109   // For Windows _interrupt_event
1110   WINDOWS_ONLY(osthread()->set_interrupted(true);)
1111 
1112   // For Thread.sleep
1113   _SleepEvent->unpark();
1114 
1115   // For JSR166 LockSupport.park
1116   parker()->unpark();
1117 
1118   // For ObjectMonitor and JvmtiRawMonitor
1119   _ParkEvent->unpark();
1120 }
1121 
1122 
1123 bool JavaThread::is_interrupted(bool clear_interrupted) {
1124   debug_only(check_for_dangling_thread_pointer(this);)
1125 
1126   if (_threadObj.peek() == NULL) {
1127     // If there is no j.l.Thread then it is impossible to have
1128     // been interrupted. We can find NULL during VM initialization
1129     // or when a JNI thread is still in the process of attaching.
1130     // In such cases this must be the current thread.
1131     assert(this == Thread::current(), "invariant");
1132     return false;
1133   }
1134 
1135   bool interrupted = java_lang_Thread::interrupted(threadObj());
1136 
1137   // NOTE that since there is no "lock" around the interrupt and
1138   // is_interrupted operations, there is the possibility that the
1139   // interrupted flag will be "false" but that the
1140   // low-level events will be in the signaled state. This is
1141   // intentional. The effect of this is that Object.wait() and
1142   // LockSupport.park() will appear to have a spurious wakeup, which
1143   // is allowed and not harmful, and the possibility is so rare that
1144   // it is not worth the added complexity to add yet another lock.
1145   // For the sleep event an explicit reset is performed on entry
1146   // to JavaThread::sleep, so there is no early return. It has also been
1147   // recommended not to put the interrupted flag into the "event"
1148   // structure because it hides the issue.
1149   // Also, because there is no lock, we must only clear the interrupt
1150   // state if we are going to report that we were interrupted; otherwise
1151   // an interrupt that happens just after we read the field would be lost.
1152   if (interrupted && clear_interrupted) {
1153     assert(this == Thread::current(), "only the current thread can clear");
1154     java_lang_Thread::set_interrupted(threadObj(), false);
1155     WINDOWS_ONLY(osthread()->set_interrupted(false);)
1156   }
1157 
1158   return interrupted;
1159 }
1160 
1161 void JavaThread::block_if_vm_exited() {
1162   if (_terminated == _vm_exited) {
1163     // _vm_exited is set at safepoint, and Threads_lock is never released
1164     // we will block here forever.
1165     // Here we can be doing a jump from a safe state to an unsafe state without
1166     // proper transition, but it happens after the final safepoint has begun.
1167     set_thread_state(_thread_in_vm);
1168     Threads_lock->lock();
1169     ShouldNotReachHere();
1170   }
1171 }
1172 
1173 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
1174   _jni_attach_state = _not_attaching_via_jni;
1175   set_entry_point(entry_point);
1176   // Create the native thread itself.
1177   // %note runtime_23
1178   os::ThreadType thr_type = os::java_thread;
1179   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
1180                                                             os::java_thread;
1181   os::create_thread(this, thr_type, stack_sz);
1182   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1183   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1184   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1185   // the exception consists of creating the exception object & initializing it, initialization
1186   // will leave the VM via a JavaCall and then all locks must be unlocked).
1187   //
1188   // The thread is still suspended when we reach here. Thread must be explicit started
1189   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1190   // by calling Threads:add. The reason why this is not done here, is because the thread
1191   // object must be fully initialized (take a look at JVM_Start)
1192 }
1193 
1194 JavaThread::~JavaThread() {
1195 
1196   // Ask ServiceThread to release the threadObj OopHandle
1197   ServiceThread::add_oop_handle_release(_threadObj);
1198 
1199   // Return the sleep event to the free list
1200   ParkEvent::Release(_SleepEvent);
1201   _SleepEvent = NULL;
1202 
1203   // Free any remaining  previous UnrollBlock
1204   vframeArray* old_array = vframe_array_last();
1205 
1206   if (old_array != NULL) {
1207     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1208     old_array->set_unroll_block(NULL);
1209     delete old_info;
1210     delete old_array;
1211   }
1212 
1213   JvmtiDeferredUpdates* updates = deferred_updates();
1214   if (updates != NULL) {
1215     // This can only happen if thread is destroyed before deoptimization occurs.
1216     assert(updates->count() > 0, "Updates holder not deleted");
1217     // free deferred updates.
1218     delete updates;
1219     set_deferred_updates(NULL);
1220   }
1221 
1222   // All Java related clean up happens in exit
1223   ThreadSafepointState::destroy(this);
1224   if (_thread_stat != NULL) delete _thread_stat;
1225 
1226 #if INCLUDE_JVMCI
1227   if (JVMCICounterSize > 0) {
1228     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1229   }
1230 #endif // INCLUDE_JVMCI
1231 }
1232 
1233 
1234 // First JavaThread specific code executed by a new Java thread.
1235 void JavaThread::pre_run() {
1236   // empty - see comments in run()
1237 }
1238 
1239 // The main routine called by a new Java thread. This isn't overridden
1240 // by subclasses, instead different subclasses define a different "entry_point"
1241 // which defines the actual logic for that kind of thread.
1242 void JavaThread::run() {
1243   // initialize thread-local alloc buffer related fields
1244   initialize_tlab();
1245 
1246   _stack_overflow_state.create_stack_guard_pages();
1247 
1248   cache_global_variables();
1249 
1250   // Thread is now sufficiently initialized to be handled by the safepoint code as being
1251   // in the VM. Change thread state from _thread_new to _thread_in_vm
1252   assert(this->thread_state() == _thread_new, "wrong thread state");
1253   set_thread_state(_thread_in_vm);
1254 
1255   // Before a thread is on the threads list it is always safe, so after leaving the
1256   // _thread_new we should emit a instruction barrier. The distance to modified code
1257   // from here is probably far enough, but this is consistent and safe.
1258   OrderAccess::cross_modify_fence();
1259 
1260   assert(JavaThread::current() == this, "sanity check");
1261   assert(!Thread::current()->owns_locks(), "sanity check");
1262 
1263   DTRACE_THREAD_PROBE(start, this);
1264 
1265   // This operation might block. We call that after all safepoint checks for a new thread has
1266   // been completed.
1267   set_active_handles(JNIHandleBlock::allocate_block());
1268 
1269   if (JvmtiExport::should_post_thread_life()) {
1270     JvmtiExport::post_thread_start(this);
1271 
1272   }
1273 
1274   // We call another function to do the rest so we are sure that the stack addresses used
1275   // from there will be lower than the stack base just computed.
1276   thread_main_inner();
1277 }
1278 
1279 void JavaThread::thread_main_inner() {
1280   assert(JavaThread::current() == this, "sanity check");
1281   assert(_threadObj.peek() != NULL, "just checking");
1282 
1283   // Execute thread entry point unless this thread has a pending exception
1284   // or has been stopped before starting.
1285   // Note: Due to JVM_StopThread we can have pending exceptions already!
1286   if (!this->has_pending_exception() &&
1287       !java_lang_Thread::is_stillborn(this->threadObj())) {
1288     {
1289       ResourceMark rm(this);
1290       this->set_native_thread_name(this->name());
1291     }
1292     HandleMark hm(this);
1293     this->entry_point()(this, this);
1294   }
1295 
1296   DTRACE_THREAD_PROBE(stop, this);
1297 
1298   // Cleanup is handled in post_run()
1299 }
1300 
1301 // Shared teardown for all JavaThreads
1302 void JavaThread::post_run() {
1303   this->exit(false);
1304   this->unregister_thread_stack_with_NMT();
1305   // Defer deletion to here to ensure 'this' is still referenceable in call_run
1306   // for any shared tear-down.
1307   this->smr_delete();
1308 }
1309 
1310 static void ensure_join(JavaThread* thread) {
1311   // We do not need to grab the Threads_lock, since we are operating on ourself.
1312   Handle threadObj(thread, thread->threadObj());
1313   assert(threadObj.not_null(), "java thread object must exist");
1314   ObjectLocker lock(threadObj, thread);
1315   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1316   thread->clear_pending_exception();
1317   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1318   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
1319   // Clear the native thread instance - this makes isAlive return false and allows the join()
1320   // to complete once we've done the notify_all below
1321   java_lang_Thread::set_thread(threadObj(), NULL);
1322   lock.notify_all(thread);
1323   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1324   thread->clear_pending_exception();
1325 }
1326 
1327 static bool is_daemon(oop threadObj) {
1328   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1329 }
1330 
1331 // For any new cleanup additions, please check to see if they need to be applied to
1332 // cleanup_failed_attach_current_thread as well.
1333 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1334   assert(this == JavaThread::current(), "thread consistency check");
1335 
1336   elapsedTimer _timer_exit_phase1;
1337   elapsedTimer _timer_exit_phase2;
1338   elapsedTimer _timer_exit_phase3;
1339   elapsedTimer _timer_exit_phase4;
1340 
1341   if (log_is_enabled(Debug, os, thread, timer)) {
1342     _timer_exit_phase1.start();
1343   }
1344 
1345   HandleMark hm(this);
1346   Handle uncaught_exception(this, this->pending_exception());
1347   this->clear_pending_exception();
1348   Handle threadObj(this, this->threadObj());
1349   assert(threadObj.not_null(), "Java thread object should be created");
1350 
1351   if (!destroy_vm) {
1352     if (uncaught_exception.not_null()) {
1353       EXCEPTION_MARK;
1354       // Call method Thread.dispatchUncaughtException().
1355       Klass* thread_klass = vmClasses::Thread_klass();
1356       JavaValue result(T_VOID);
1357       JavaCalls::call_virtual(&result,
1358                               threadObj, thread_klass,
1359                               vmSymbols::dispatchUncaughtException_name(),
1360                               vmSymbols::throwable_void_signature(),
1361                               uncaught_exception,
1362                               THREAD);
1363       if (HAS_PENDING_EXCEPTION) {
1364         ResourceMark rm(this);
1365         jio_fprintf(defaultStream::error_stream(),
1366                     "\nException: %s thrown from the UncaughtExceptionHandler"
1367                     " in thread \"%s\"\n",
1368                     pending_exception()->klass()->external_name(),
1369                     name());
1370         CLEAR_PENDING_EXCEPTION;
1371       }
1372     }
1373 
1374     if (!is_Compiler_thread()) {
1375       // We have finished executing user-defined Java code and now have to do the
1376       // implementation specific clean-up by calling Thread.exit(). We prevent any
1377       // asynchronous exceptions from being delivered while in Thread.exit()
1378       // to ensure the clean-up is not corrupted.
1379       NoAsyncExceptionDeliveryMark _no_async(this);
1380 
1381       EXCEPTION_MARK;
1382       JavaValue result(T_VOID);
1383       Klass* thread_klass = vmClasses::Thread_klass();
1384       JavaCalls::call_virtual(&result,
1385                               threadObj, thread_klass,
1386                               vmSymbols::exit_method_name(),
1387                               vmSymbols::void_method_signature(),
1388                               THREAD);
1389       CLEAR_PENDING_EXCEPTION;
1390     }
1391 
1392     // notify JVMTI
1393     if (JvmtiExport::should_post_thread_life()) {
1394       JvmtiExport::post_thread_end(this);
1395     }
1396 
1397     // The careful dance between thread suspension and exit is handled here.
1398     // Since we are in thread_in_vm state and suspension is done with handshakes,
1399     // we can just put in the exiting state and it will be correctly handled.
1400     set_terminated(_thread_exiting);
1401 
1402     ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1403   } else {
1404     assert(!is_terminated() && !is_exiting(), "must not be exiting");
1405     // before_exit() has already posted JVMTI THREAD_END events
1406   }
1407 
1408   if (log_is_enabled(Debug, os, thread, timer)) {
1409     _timer_exit_phase1.stop();
1410     _timer_exit_phase2.start();
1411   }
1412 
1413   // Capture daemon status before the thread is marked as terminated.
1414   bool daemon = is_daemon(threadObj());
1415 
1416   // Notify waiters on thread object. This has to be done after exit() is called
1417   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1418   // group should have the destroyed bit set before waiters are notified).
1419   ensure_join(this);
1420   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1421 
1422   if (log_is_enabled(Debug, os, thread, timer)) {
1423     _timer_exit_phase2.stop();
1424     _timer_exit_phase3.start();
1425   }
1426   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1427   // held by this thread must be released. The spec does not distinguish
1428   // between JNI-acquired and regular Java monitors. We can only see
1429   // regular Java monitors here if monitor enter-exit matching is broken.
1430   //
1431   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1432   // ObjectSynchronizer::release_monitors_owned_by_thread().
1433   if (exit_type == jni_detach) {
1434     // Sanity check even though JNI DetachCurrentThread() would have
1435     // returned JNI_ERR if there was a Java frame. JavaThread exit
1436     // should be done executing Java code by the time we get here.
1437     assert(!this->has_last_Java_frame(),
1438            "should not have a Java frame when detaching or exiting");
1439     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1440     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1441   }
1442 
1443   // These things needs to be done while we are still a Java Thread. Make sure that thread
1444   // is in a consistent state, in case GC happens
1445   JFR_ONLY(Jfr::on_thread_exit(this);)
1446 
1447   if (active_handles() != NULL) {
1448     JNIHandleBlock* block = active_handles();
1449     set_active_handles(NULL);
1450     JNIHandleBlock::release_block(block);
1451   }
1452 
1453   if (free_handle_block() != NULL) {
1454     JNIHandleBlock* block = free_handle_block();
1455     set_free_handle_block(NULL);
1456     JNIHandleBlock::release_block(block);
1457   }
1458 
1459   // These have to be removed while this is still a valid thread.
1460   _stack_overflow_state.remove_stack_guard_pages();
1461 
1462   if (UseTLAB) {
1463     tlab().retire();
1464   }
1465 
1466   if (JvmtiEnv::environments_might_exist()) {
1467     JvmtiExport::cleanup_thread(this);
1468   }
1469 
1470   // We need to cache the thread name for logging purposes below as once
1471   // we have called on_thread_detach this thread must not access any oops.
1472   char* thread_name = NULL;
1473   if (log_is_enabled(Debug, os, thread, timer)) {
1474     ResourceMark rm(this);
1475     thread_name = os::strdup(name());
1476   }
1477 
1478   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1479     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1480     os::current_thread_id());
1481 
1482   if (log_is_enabled(Debug, os, thread, timer)) {
1483     _timer_exit_phase3.stop();
1484     _timer_exit_phase4.start();
1485   }
1486 
1487 #if INCLUDE_JVMCI
1488   if (JVMCICounterSize > 0) {
1489     if (jvmci_counters_include(this)) {
1490       for (int i = 0; i < JVMCICounterSize; i++) {
1491         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1492       }
1493     }
1494   }
1495 #endif // INCLUDE_JVMCI
1496 
1497   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1498   Threads::remove(this, daemon);
1499 
1500   if (log_is_enabled(Debug, os, thread, timer)) {
1501     _timer_exit_phase4.stop();
1502     log_debug(os, thread, timer)("name='%s'"
1503                                  ", exit-phase1=" JLONG_FORMAT
1504                                  ", exit-phase2=" JLONG_FORMAT
1505                                  ", exit-phase3=" JLONG_FORMAT
1506                                  ", exit-phase4=" JLONG_FORMAT,
1507                                  thread_name,
1508                                  _timer_exit_phase1.milliseconds(),
1509                                  _timer_exit_phase2.milliseconds(),
1510                                  _timer_exit_phase3.milliseconds(),
1511                                  _timer_exit_phase4.milliseconds());
1512     os::free(thread_name);
1513   }
1514 }
1515 
1516 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1517   if (active_handles() != NULL) {
1518     JNIHandleBlock* block = active_handles();
1519     set_active_handles(NULL);
1520     JNIHandleBlock::release_block(block);
1521   }
1522 
1523   if (free_handle_block() != NULL) {
1524     JNIHandleBlock* block = free_handle_block();
1525     set_free_handle_block(NULL);
1526     JNIHandleBlock::release_block(block);
1527   }
1528 
1529   // These have to be removed while this is still a valid thread.
1530   _stack_overflow_state.remove_stack_guard_pages();
1531 
1532   if (UseTLAB) {
1533     tlab().retire();
1534   }
1535 
1536   Threads::remove(this, is_daemon);
1537   this->smr_delete();
1538 }
1539 
1540 JavaThread* JavaThread::active() {
1541   Thread* thread = Thread::current();
1542   if (thread->is_Java_thread()) {
1543     return JavaThread::cast(thread);
1544   } else {
1545     assert(thread->is_VM_thread(), "this must be a vm thread");
1546     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1547     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
1548     return ret;
1549   }
1550 }
1551 
1552 bool JavaThread::is_lock_owned(address adr) const {
1553   if (Thread::is_lock_owned(adr)) return true;
1554 
1555   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1556     if (chunk->contains(adr)) return true;
1557   }
1558 
1559   return false;
1560 }
1561 
1562 oop JavaThread::exception_oop() const {
1563   return Atomic::load(&_exception_oop);
1564 }
1565 
1566 void JavaThread::set_exception_oop(oop o) {
1567   Atomic::store(&_exception_oop, o);
1568 }
1569 
1570 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1571   chunk->set_next(monitor_chunks());
1572   set_monitor_chunks(chunk);
1573 }
1574 
1575 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1576   guarantee(monitor_chunks() != NULL, "must be non empty");
1577   if (monitor_chunks() == chunk) {
1578     set_monitor_chunks(chunk->next());
1579   } else {
1580     MonitorChunk* prev = monitor_chunks();
1581     while (prev->next() != chunk) prev = prev->next();
1582     prev->set_next(chunk->next());
1583   }
1584 }
1585 
1586 void JavaThread::handle_special_runtime_exit_condition() {
1587   if (is_obj_deopt_suspend()) {
1588     frame_anchor()->make_walkable(this);
1589     wait_for_object_deoptimization();
1590   }
1591   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1592 }
1593 
1594 
1595 // Asynchronous exceptions support
1596 //
1597 void JavaThread::handle_async_exception(oop java_throwable) {
1598   assert(java_throwable != NULL, "should have an _async_exception to throw");
1599   assert(!is_at_poll_safepoint(), "should have never called this method");
1600 
1601   if (has_last_Java_frame()) {
1602     frame f = last_frame();
1603     if (f.is_runtime_frame()) {
1604       // If the topmost frame is a runtime stub, then we are calling into
1605       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1606       // must deoptimize the caller before continuing, as the compiled exception
1607       // handler table may not be valid.
1608       RegisterMap reg_map(this, false);
1609       frame compiled_frame = f.sender(&reg_map);
1610       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1611         Deoptimization::deoptimize(this, compiled_frame);
1612       }
1613     }
1614   }
1615 
1616   // Only overwrite an already pending exception if it is not a ThreadDeath.
1617   if (!has_pending_exception() || !pending_exception()->is_a(vmClasses::ThreadDeath_klass())) {
1618 
1619     // We cannot call Exceptions::_throw(...) here because we cannot block
1620     set_pending_exception(java_throwable, __FILE__, __LINE__);
1621 
1622     LogTarget(Info, exceptions) lt;
1623     if (lt.is_enabled()) {
1624       ResourceMark rm;
1625       LogStream ls(lt);
1626       ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1627       if (has_last_Java_frame()) {
1628         frame f = last_frame();
1629         ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1630       }
1631       ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1632     }
1633   }
1634 }
1635 
1636 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1637   // Do not throw asynchronous exceptions against the compiler thread.
1638   if (!can_call_java()) {
1639     delete aeh;
1640     return;
1641   }
1642 
1643   // Don't install a new pending async exception if there is already
1644   // a pending ThreadDeath one. Just interrupt thread from potential
1645   // wait()/sleep()/park() and return.
1646   if (has_async_exception_condition(true /* ThreadDeath_only */)) {
1647     java_lang_Thread::set_interrupted(threadObj(), true);
1648     this->interrupt();
1649     delete aeh;
1650     return;
1651   }
1652 
1653   oop exception = aeh->exception();
1654   Handshake::execute(aeh, this);  // Install asynchronous handshake
1655 
1656   ResourceMark rm;
1657   if (log_is_enabled(Info, exceptions)) {
1658     log_info(exceptions)("Pending Async. exception installed of type: %s",
1659                          InstanceKlass::cast(exception->klass())->external_name());
1660   }
1661   // for AbortVMOnException flag
1662   Exceptions::debug_check_abort(exception->klass()->external_name());
1663 
1664   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1665   java_lang_Thread::set_interrupted(threadObj(), true);
1666   this->interrupt();
1667 }
1668 
1669 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1670   AsyncExceptionHandshake* _aeh;
1671 public:
1672   InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1673     HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1674   void do_thread(Thread* thr) {
1675     JavaThread* target = JavaThread::cast(thr);
1676     target->install_async_exception(_aeh);
1677   }
1678 };
1679 
1680 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1681   OopHandle e(Universe::vm_global(), java_throwable);
1682   InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1683   Handshake::execute(&iaeh, target);
1684 }
1685 
1686 
1687 // External suspension mechanism.
1688 //
1689 // Guarantees on return (for a valid target thread):
1690 //   - Target thread will not execute any new bytecode.
1691 //   - Target thread will not enter any new monitors.
1692 //
1693 bool JavaThread::java_suspend() {
1694   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1695             "missing ThreadsListHandle in calling context.");
1696   return this->handshake_state()->suspend();
1697 }
1698 
1699 bool JavaThread::java_resume() {
1700   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1701             "missing ThreadsListHandle in calling context.");
1702   return this->handshake_state()->resume();
1703 }
1704 
1705 // Wait for another thread to perform object reallocation and relocking on behalf of
1706 // this thread. The current thread is required to change to _thread_blocked in order
1707 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1708 // handshake safe, the other thread can complete the handshake used to synchronize
1709 // with this thread and then perform the reallocation and relocking.
1710 // See EscapeBarrier::sync_and_suspend_*()
1711 
1712 void JavaThread::wait_for_object_deoptimization() {
1713   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1714   assert(this == Thread::current(), "invariant");
1715 
1716   bool spin_wait = os::is_MP();
1717   do {
1718     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1719     // Wait for object deoptimization if requested.
1720     if (spin_wait) {
1721       // A single deoptimization is typically very short. Microbenchmarks
1722       // showed 5% better performance when spinning.
1723       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1724       SpinYield spin(spin_limit);
1725       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1726         spin.wait();
1727       }
1728       // Spin just once
1729       spin_wait = false;
1730     } else {
1731       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1732       if (is_obj_deopt_suspend()) {
1733         ml.wait();
1734       }
1735     }
1736     // A handshake for obj. deoptimization suspend could have been processed so
1737     // we must check after processing.
1738   } while (is_obj_deopt_suspend());
1739 }
1740 
1741 #ifdef ASSERT
1742 // Verify the JavaThread has not yet been published in the Threads::list, and
1743 // hence doesn't need protection from concurrent access at this stage.
1744 void JavaThread::verify_not_published() {
1745   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1746   // since an unpublished JavaThread doesn't participate in the
1747   // Thread-SMR protocol for keeping a ThreadsList alive.
1748   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1749 }
1750 #endif
1751 
1752 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1753 // pending, when _suspend_flags is non-zero or when we need to process a stack
1754 // watermark. Also check for pending async exceptions (except unsafe access error).
1755 // Note only the native==>Java barriers can call this function when thread state
1756 // is _thread_in_native_trans.
1757 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1758   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1759   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1760 
1761   thread->set_thread_state(_thread_in_vm);
1762 
1763   // Enable WXWrite: called directly from interpreter native wrapper.
1764   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1765 
1766   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1767 
1768   // After returning from native, it could be that the stack frames are not
1769   // yet safe to use. We catch such situations in the subsequent stack watermark
1770   // barrier, which will trap unsafe stack frames.
1771   StackWatermarkSet::before_unwind(thread);
1772 }
1773 
1774 #ifndef PRODUCT
1775 // Deoptimization
1776 // Function for testing deoptimization
1777 void JavaThread::deoptimize() {
1778   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1779   bool deopt = false;           // Dump stack only if a deopt actually happens.
1780   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1781   // Iterate over all frames in the thread and deoptimize
1782   for (; !fst.is_done(); fst.next()) {
1783     if (fst.current()->can_be_deoptimized()) {
1784 
1785       if (only_at) {
1786         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1787         // consists of comma or carriage return separated numbers so
1788         // search for the current bci in that string.
1789         address pc = fst.current()->pc();
1790         nmethod* nm =  (nmethod*) fst.current()->cb();
1791         ScopeDesc* sd = nm->scope_desc_at(pc);
1792         char buffer[8];
1793         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1794         size_t len = strlen(buffer);
1795         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1796         while (found != NULL) {
1797           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1798               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1799             // Check that the bci found is bracketed by terminators.
1800             break;
1801           }
1802           found = strstr(found + 1, buffer);
1803         }
1804         if (!found) {
1805           continue;
1806         }
1807       }
1808 
1809       if (DebugDeoptimization && !deopt) {
1810         deopt = true; // One-time only print before deopt
1811         tty->print_cr("[BEFORE Deoptimization]");
1812         trace_frames();
1813         trace_stack();
1814       }
1815       Deoptimization::deoptimize(this, *fst.current());
1816     }
1817   }
1818 
1819   if (DebugDeoptimization && deopt) {
1820     tty->print_cr("[AFTER Deoptimization]");
1821     trace_frames();
1822   }
1823 }
1824 
1825 
1826 // Make zombies
1827 void JavaThread::make_zombies() {
1828   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1829     if (fst.current()->can_be_deoptimized()) {
1830       // it is a Java nmethod
1831       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1832       nm->make_not_entrant();
1833     }
1834   }
1835 }
1836 #endif // PRODUCT
1837 
1838 
1839 void JavaThread::deoptimize_marked_methods() {
1840   if (!has_last_Java_frame()) return;
1841   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1842   for (; !fst.is_done(); fst.next()) {
1843     if (fst.current()->should_be_deoptimized()) {
1844       Deoptimization::deoptimize(this, *fst.current());
1845     }
1846   }
1847 }
1848 
1849 #ifdef ASSERT
1850 void JavaThread::verify_frame_info() {
1851   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1852          (has_last_Java_frame() && java_call_counter() > 0),
1853          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1854          has_last_Java_frame() ? "true" : "false", java_call_counter());
1855 }
1856 #endif
1857 
1858 // Push on a new block of JNI handles.
1859 void JavaThread::push_jni_handle_block() {
1860   // Allocate a new block for JNI handles.
1861   // Inlined code from jni_PushLocalFrame()
1862   JNIHandleBlock* old_handles = active_handles();
1863   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1864   assert(old_handles != NULL && new_handles != NULL, "should not be NULL");
1865   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1866   set_active_handles(new_handles);
1867 }
1868 
1869 // Pop off the current block of JNI handles.
1870 void JavaThread::pop_jni_handle_block() {
1871   // Release our JNI handle block
1872   JNIHandleBlock* old_handles = active_handles();
1873   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1874   assert(new_handles != nullptr, "should never set active handles to null");
1875   set_active_handles(new_handles);
1876   old_handles->set_pop_frame_link(NULL);
1877   JNIHandleBlock::release_block(old_handles, this);
1878 }
1879 
1880 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1881   // Verify that the deferred card marks have been flushed.
1882   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1883 
1884   // Traverse the GCHandles
1885   Thread::oops_do_no_frames(f, cf);
1886 
1887   if (active_handles() != NULL) {
1888     active_handles()->oops_do(f);
1889   }
1890 
1891   DEBUG_ONLY(verify_frame_info();)
1892 
1893   if (has_last_Java_frame()) {
1894     // Traverse the monitor chunks
1895     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1896       chunk->oops_do(f);
1897     }
1898   }
1899 
1900   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1901   // If we have deferred set_locals there might be oops waiting to be
1902   // written
1903   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1904   if (list != NULL) {
1905     for (int i = 0; i < list->length(); i++) {
1906       list->at(i)->oops_do(f);
1907     }
1908   }
1909 
1910   // Traverse instance variables at the end since the GC may be moving things
1911   // around using this function
1912   f->do_oop((oop*) &_vm_result);
1913   f->do_oop((oop*) &_exception_oop);
1914 #if INCLUDE_JVMCI
1915   f->do_oop((oop*) &_jvmci_reserved_oop0);
1916 #endif
1917 
1918   if (jvmti_thread_state() != NULL) {
1919     jvmti_thread_state()->oops_do(f, cf);
1920   }
1921 }
1922 
1923 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1924   if (!has_last_Java_frame()) {
1925     return;
1926   }
1927   // Finish any pending lazy GC activity for the frames
1928   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1929   // Traverse the execution stack
1930   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1931     fst.current()->oops_do(f, cf, fst.register_map());
1932   }
1933 }
1934 
1935 #ifdef ASSERT
1936 void JavaThread::verify_states_for_handshake() {
1937   // This checks that the thread has a correct frame state during a handshake.
1938   verify_frame_info();
1939 }
1940 #endif
1941 
1942 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1943   DEBUG_ONLY(verify_frame_info();)
1944 
1945   if (has_last_Java_frame()) {
1946     // Traverse the execution stack
1947     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1948       fst.current()->nmethods_do(cf);
1949     }
1950   }
1951 
1952   if (jvmti_thread_state() != NULL) {
1953     jvmti_thread_state()->nmethods_do(cf);
1954   }
1955 }
1956 
1957 void JavaThread::metadata_do(MetadataClosure* f) {
1958   if (has_last_Java_frame()) {
1959     // Traverse the execution stack to call f() on the methods in the stack
1960     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1961       fst.current()->metadata_do(f);
1962     }
1963   } else if (is_Compiler_thread()) {
1964     // need to walk ciMetadata in current compile tasks to keep alive.
1965     CompilerThread* ct = (CompilerThread*)this;
1966     if (ct->env() != NULL) {
1967       ct->env()->metadata_do(f);
1968     }
1969     CompileTask* task = ct->task();
1970     if (task != NULL) {
1971       task->metadata_do(f);
1972     }
1973   }
1974 }
1975 
1976 // Printing
1977 const char* _get_thread_state_name(JavaThreadState _thread_state) {
1978   switch (_thread_state) {
1979   case _thread_uninitialized:     return "_thread_uninitialized";
1980   case _thread_new:               return "_thread_new";
1981   case _thread_new_trans:         return "_thread_new_trans";
1982   case _thread_in_native:         return "_thread_in_native";
1983   case _thread_in_native_trans:   return "_thread_in_native_trans";
1984   case _thread_in_vm:             return "_thread_in_vm";
1985   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1986   case _thread_in_Java:           return "_thread_in_Java";
1987   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1988   case _thread_blocked:           return "_thread_blocked";
1989   case _thread_blocked_trans:     return "_thread_blocked_trans";
1990   default:                        return "unknown thread state";
1991   }
1992 }
1993 
1994 #ifndef PRODUCT
1995 void JavaThread::print_thread_state_on(outputStream *st) const {
1996   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1997 };
1998 #endif // PRODUCT
1999 
2000 // Called by Threads::print() for VM_PrintThreads operation
2001 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2002   st->print_raw("\"");
2003   st->print_raw(name());
2004   st->print_raw("\" ");
2005   oop thread_oop = threadObj();
2006   if (thread_oop != NULL) {
2007     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2008     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2009     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2010   }
2011   Thread::print_on(st, print_extended_info);
2012   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2013   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2014   if (thread_oop != NULL) {
2015     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2016   }
2017 #ifndef PRODUCT
2018   _safepoint_state->print_on(st);
2019 #endif // PRODUCT
2020   if (is_Compiler_thread()) {
2021     CompileTask *task = ((CompilerThread*)this)->task();
2022     if (task != NULL) {
2023       st->print("   Compiling: ");
2024       task->print(st, NULL, true, false);
2025     } else {
2026       st->print("   No compile task");
2027     }
2028     st->cr();
2029   }
2030 }
2031 
2032 void JavaThread::print() const { print_on(tty); }
2033 
2034 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2035   st->print("%s", get_thread_name_string(buf, buflen));
2036 }
2037 
2038 // Called by fatal error handler. The difference between this and
2039 // JavaThread::print() is that we can't grab lock or allocate memory.
2040 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2041   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
2042   oop thread_obj = threadObj();
2043   if (thread_obj != NULL) {
2044     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2045   }
2046   st->print(" [");
2047   st->print("%s", _get_thread_state_name(_thread_state));
2048   if (osthread()) {
2049     st->print(", id=%d", osthread()->thread_id());
2050   }
2051   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2052             p2i(stack_end()), p2i(stack_base()));
2053   st->print("]");
2054 
2055   ThreadsSMRSupport::print_info_on(this, st);
2056   return;
2057 }
2058 
2059 
2060 // Verification
2061 
2062 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2063   // ignore if there is no stack
2064   if (!has_last_Java_frame()) return;
2065   // traverse the stack frames. Starts from top frame.
2066   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2067     frame* fr = fst.current();
2068     f(fr, fst.register_map());
2069   }
2070 }
2071 
2072 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2073 
2074 void JavaThread::verify() {
2075   // Verify oops in the thread.
2076   oops_do(&VerifyOopClosure::verify_oop, NULL);
2077 
2078   // Verify the stack frames.
2079   frames_do(frame_verify);
2080 }
2081 
2082 // CR 6300358 (sub-CR 2137150)
2083 // Most callers of this method assume that it can't return NULL but a
2084 // thread may not have a name whilst it is in the process of attaching to
2085 // the VM - see CR 6412693, and there are places where a JavaThread can be
2086 // seen prior to having its threadObj set (e.g., JNI attaching threads and
2087 // if vm exit occurs during initialization). These cases can all be accounted
2088 // for such that this method never returns NULL.
2089 const char* JavaThread::name() const  {
2090   if (Thread::is_JavaThread_protected(/* target */ this)) {
2091     // The target JavaThread is protected so get_thread_name_string() is safe:
2092     return get_thread_name_string();
2093   }
2094 
2095   // The target JavaThread is not protected so we return the default:
2096   return Thread::name();
2097 }
2098 
2099 // Returns a non-NULL representation of this thread's name, or a suitable
2100 // descriptive string if there is no set name.
2101 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2102   const char* name_str;
2103   oop thread_obj = threadObj();
2104   if (thread_obj != NULL) {
2105     oop name = java_lang_Thread::name(thread_obj);
2106     if (name != NULL) {
2107       if (buf == NULL) {
2108         name_str = java_lang_String::as_utf8_string(name);
2109       } else {
2110         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2111       }
2112     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2113       name_str = "<no-name - thread is attaching>";
2114     } else {
2115       name_str = "<un-named>";
2116     }
2117   } else {
2118     name_str = Thread::name();
2119   }
2120   assert(name_str != NULL, "unexpected NULL thread name");
2121   return name_str;
2122 }
2123 
2124 // Helper to extract the name from the thread oop for logging.
2125 const char* JavaThread::name_for(oop thread_obj) {
2126   assert(thread_obj != NULL, "precondition");
2127   oop name = java_lang_Thread::name(thread_obj);
2128   const char* name_str;
2129   if (name != NULL) {
2130     name_str = java_lang_String::as_utf8_string(name);
2131   } else {
2132     name_str = "<un-named>";
2133   }
2134   return name_str;
2135 }
2136 
2137 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2138 
2139   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2140   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
2141   // Link Java Thread object <-> C++ Thread
2142 
2143   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2144   // and put it into a new Handle.  The Handle "thread_oop" can then
2145   // be used to pass the C++ thread object to other methods.
2146 
2147   // Set the Java level thread object (jthread) field of the
2148   // new thread (a JavaThread *) to C++ thread object using the
2149   // "thread_oop" handle.
2150 
2151   // Set the thread field (a JavaThread *) of the
2152   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2153 
2154   Handle thread_oop(Thread::current(),
2155                     JNIHandles::resolve_non_null(jni_thread));
2156   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2157          "must be initialized");
2158   set_threadObj(thread_oop());
2159   java_lang_Thread::set_thread(thread_oop(), this);
2160 
2161   if (prio == NoPriority) {
2162     prio = java_lang_Thread::priority(thread_oop());
2163     assert(prio != NoPriority, "A valid priority should be present");
2164   }
2165 
2166   // Push the Java priority down to the native thread; needs Threads_lock
2167   Thread::set_priority(this, prio);
2168 
2169   // Add the new thread to the Threads list and set it in motion.
2170   // We must have threads lock in order to call Threads::add.
2171   // It is crucial that we do not block before the thread is
2172   // added to the Threads list for if a GC happens, then the java_thread oop
2173   // will not be visited by GC.
2174   Threads::add(this);
2175 }
2176 
2177 oop JavaThread::current_park_blocker() {
2178   // Support for JSR-166 locks
2179   oop thread_oop = threadObj();
2180   if (thread_oop != NULL) {
2181     return java_lang_Thread::park_blocker(thread_oop);
2182   }
2183   return NULL;
2184 }
2185 
2186 
2187 void JavaThread::print_stack_on(outputStream* st) {
2188   if (!has_last_Java_frame()) return;
2189 
2190   Thread* current_thread = Thread::current();
2191   ResourceMark rm(current_thread);
2192   HandleMark hm(current_thread);
2193 
2194   RegisterMap reg_map(this);
2195   vframe* start_vf = last_java_vframe(&reg_map);
2196   int count = 0;
2197   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
2198     if (f->is_java_frame()) {
2199       javaVFrame* jvf = javaVFrame::cast(f);
2200       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2201 
2202       // Print out lock information
2203       if (JavaMonitorsInStackTrace) {
2204         jvf->print_lock_info_on(st, count);
2205       }
2206     } else {
2207       // Ignore non-Java frames
2208     }
2209 
2210     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
2211     count++;
2212     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
2213   }
2214 }
2215 
2216 
2217 // JVMTI PopFrame support
2218 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2219   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2220   if (in_bytes(size_in_bytes) != 0) {
2221     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2222     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2223     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2224   }
2225 }
2226 
2227 void* JavaThread::popframe_preserved_args() {
2228   return _popframe_preserved_args;
2229 }
2230 
2231 ByteSize JavaThread::popframe_preserved_args_size() {
2232   return in_ByteSize(_popframe_preserved_args_size);
2233 }
2234 
2235 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2236   int sz = in_bytes(popframe_preserved_args_size());
2237   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2238   return in_WordSize(sz / wordSize);
2239 }
2240 
2241 void JavaThread::popframe_free_preserved_args() {
2242   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2243   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
2244   _popframe_preserved_args = NULL;
2245   _popframe_preserved_args_size = 0;
2246 }
2247 
2248 #ifndef PRODUCT
2249 
2250 void JavaThread::trace_frames() {
2251   tty->print_cr("[Describe stack]");
2252   int frame_no = 1;
2253   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2254     tty->print("  %d. ", frame_no++);
2255     fst.current()->print_value_on(tty, this);
2256     tty->cr();
2257   }
2258 }
2259 
2260 class PrintAndVerifyOopClosure: public OopClosure {
2261  protected:
2262   template <class T> inline void do_oop_work(T* p) {
2263     oop obj = RawAccess<>::oop_load(p);
2264     if (obj == NULL) return;
2265     tty->print(INTPTR_FORMAT ": ", p2i(p));
2266     if (oopDesc::is_oop_or_null(obj)) {
2267       if (obj->is_objArray()) {
2268         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
2269       } else {
2270         obj->print();
2271       }
2272     } else {
2273       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
2274     }
2275     tty->cr();
2276   }
2277  public:
2278   virtual void do_oop(oop* p) { do_oop_work(p); }
2279   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
2280 };
2281 
2282 #ifdef ASSERT
2283 // Print or validate the layout of stack frames
2284 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2285   ResourceMark rm;
2286   PreserveExceptionMark pm(this);
2287   FrameValues values;
2288   int frame_no = 0;
2289   for (StackFrameStream fst(this, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2290     fst.current()->describe(values, ++frame_no);
2291     if (depth == frame_no) break;
2292   }
2293   if (validate_only) {
2294     values.validate();
2295   } else {
2296     tty->print_cr("[Describe stack layout]");
2297     values.print(this);
2298   }
2299 }
2300 #endif
2301 
2302 void JavaThread::trace_stack_from(vframe* start_vf) {
2303   ResourceMark rm;
2304   int vframe_no = 1;
2305   for (vframe* f = start_vf; f; f = f->sender()) {
2306     if (f->is_java_frame()) {
2307       javaVFrame::cast(f)->print_activation(vframe_no++);
2308     } else {
2309       f->print();
2310     }
2311     if (vframe_no > StackPrintLimit) {
2312       tty->print_cr("...<more frames>...");
2313       return;
2314     }
2315   }
2316 }
2317 
2318 
2319 void JavaThread::trace_stack() {
2320   if (!has_last_Java_frame()) return;
2321   Thread* current_thread = Thread::current();
2322   ResourceMark rm(current_thread);
2323   HandleMark hm(current_thread);
2324   RegisterMap reg_map(this);
2325   trace_stack_from(last_java_vframe(&reg_map));
2326 }
2327 
2328 
2329 #endif // PRODUCT
2330 
2331 
2332 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2333   assert(reg_map != NULL, "a map must be given");
2334   frame f = last_frame();
2335   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2336     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2337   }
2338   return NULL;
2339 }
2340 
2341 
2342 Klass* JavaThread::security_get_caller_class(int depth) {
2343   vframeStream vfst(this);
2344   vfst.security_get_caller_frame(depth);
2345   if (!vfst.at_end()) {
2346     return vfst.method()->method_holder();
2347   }
2348   return NULL;
2349 }
2350 
2351 // java.lang.Thread.sleep support
2352 // Returns true if sleep time elapsed as expected, and false
2353 // if the thread was interrupted.
2354 bool JavaThread::sleep(jlong millis) {
2355   assert(this == Thread::current(),  "thread consistency check");
2356 
2357   ParkEvent * const slp = this->_SleepEvent;
2358   // Because there can be races with thread interruption sending an unpark()
2359   // to the event, we explicitly reset it here to avoid an immediate return.
2360   // The actual interrupt state will be checked before we park().
2361   slp->reset();
2362   // Thread interruption establishes a happens-before ordering in the
2363   // Java Memory Model, so we need to ensure we synchronize with the
2364   // interrupt state.
2365   OrderAccess::fence();
2366 
2367   jlong prevtime = os::javaTimeNanos();
2368 
2369   for (;;) {
2370     // interruption has precedence over timing out
2371     if (this->is_interrupted(true)) {
2372       return false;
2373     }
2374 
2375     if (millis <= 0) {
2376       return true;
2377     }
2378 
2379     {
2380       ThreadBlockInVM tbivm(this);
2381       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2382       slp->park(millis);
2383     }
2384 
2385     // Update elapsed time tracking
2386     jlong newtime = os::javaTimeNanos();
2387     if (newtime - prevtime < 0) {
2388       // time moving backwards, should only happen if no monotonic clock
2389       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2390       assert(false,
2391              "unexpected time moving backwards detected in JavaThread::sleep()");
2392     } else {
2393       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2394     }
2395     prevtime = newtime;
2396   }
2397 }
2398 
2399 
2400 // ======= Threads ========
2401 
2402 // The Threads class links together all active threads, and provides
2403 // operations over all threads. It is protected by the Threads_lock,
2404 // which is also used in other global contexts like safepointing.
2405 // ThreadsListHandles are used to safely perform operations on one
2406 // or more threads without the risk of the thread exiting during the
2407 // operation.
2408 //
2409 // Note: The Threads_lock is currently more widely used than we
2410 // would like. We are actively migrating Threads_lock uses to other
2411 // mechanisms in order to reduce Threads_lock contention.
2412 
2413 int         Threads::_number_of_threads = 0;
2414 int         Threads::_number_of_non_daemon_threads = 0;
2415 int         Threads::_return_code = 0;
2416 uintx       Threads::_thread_claim_token = 1; // Never zero.
2417 size_t      JavaThread::_stack_size_at_create = 0;
2418 
2419 #ifdef ASSERT
2420 bool        Threads::_vm_complete = false;
2421 #endif
2422 
2423 // All NonJavaThreads (i.e., every non-JavaThread in the system).
2424 void Threads::non_java_threads_do(ThreadClosure* tc) {
2425   NoSafepointVerifier nsv;
2426   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
2427     tc->do_thread(njti.current());
2428   }
2429 }
2430 
2431 // All JavaThreads
2432 #define ALL_JAVA_THREADS(X) \
2433   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
2434 
2435 // All JavaThreads
2436 void Threads::java_threads_do(ThreadClosure* tc) {
2437   assert_locked_or_safepoint(Threads_lock);
2438   // ALL_JAVA_THREADS iterates through all JavaThreads.
2439   ALL_JAVA_THREADS(p) {
2440     tc->do_thread(p);
2441   }
2442 }
2443 
2444 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
2445   assert_locked_or_safepoint(Threads_lock);
2446   java_threads_do(tc);
2447   tc->do_thread(VMThread::vm_thread());
2448 }
2449 
2450 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
2451 void Threads::threads_do(ThreadClosure* tc) {
2452   assert_locked_or_safepoint(Threads_lock);
2453   java_threads_do(tc);
2454   non_java_threads_do(tc);
2455 }
2456 
2457 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
2458   uintx claim_token = Threads::thread_claim_token();
2459   ALL_JAVA_THREADS(p) {
2460     if (p->claim_threads_do(is_par, claim_token)) {
2461       tc->do_thread(p);
2462     }
2463   }
2464   VMThread* vmt = VMThread::vm_thread();
2465   if (vmt->claim_threads_do(is_par, claim_token)) {
2466     tc->do_thread(vmt);
2467   }
2468 }
2469 
2470 // The system initialization in the library has three phases.
2471 //
2472 // Phase 1: java.lang.System class initialization
2473 //     java.lang.System is a primordial class loaded and initialized
2474 //     by the VM early during startup.  java.lang.System.<clinit>
2475 //     only does registerNatives and keeps the rest of the class
2476 //     initialization work later until thread initialization completes.
2477 //
2478 //     System.initPhase1 initializes the system properties, the static
2479 //     fields in, out, and err. Set up java signal handlers, OS-specific
2480 //     system settings, and thread group of the main thread.
2481 static void call_initPhase1(TRAPS) {
2482   Klass* klass = vmClasses::System_klass();
2483   JavaValue result(T_VOID);
2484   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
2485                                          vmSymbols::void_method_signature(), CHECK);
2486 }
2487 
2488 // Phase 2. Module system initialization
2489 //     This will initialize the module system.  Only java.base classes
2490 //     can be loaded until phase 2 completes.
2491 //
2492 //     Call System.initPhase2 after the compiler initialization and jsr292
2493 //     classes get initialized because module initialization runs a lot of java
2494 //     code, that for performance reasons, should be compiled.  Also, this will
2495 //     enable the startup code to use lambda and other language features in this
2496 //     phase and onward.
2497 //
2498 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
2499 static void call_initPhase2(TRAPS) {
2500   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
2501 
2502   Klass* klass = vmClasses::System_klass();
2503 
2504   JavaValue result(T_INT);
2505   JavaCallArguments args;
2506   args.push_int(DisplayVMOutputToStderr);
2507   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
2508   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
2509                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
2510   if (result.get_jint() != JNI_OK) {
2511     vm_exit_during_initialization(); // no message or exception
2512   }
2513 
2514   universe_post_module_init();
2515 }
2516 
2517 // Phase 3. final setup - set security manager, system class loader and TCCL
2518 //
2519 //     This will instantiate and set the security manager, set the system class
2520 //     loader as well as the thread context class loader.  The security manager
2521 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
2522 //     other modules or the application's classpath.
2523 static void call_initPhase3(TRAPS) {
2524   Klass* klass = vmClasses::System_klass();
2525   JavaValue result(T_VOID);
2526   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
2527                                          vmSymbols::void_method_signature(), CHECK);
2528 }
2529 
2530 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
2531   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
2532 
2533   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2534     create_vm_init_libraries();
2535   }
2536 
2537   initialize_class(vmSymbols::java_lang_String(), CHECK);
2538 
2539   // Inject CompactStrings value after the static initializers for String ran.
2540   java_lang_String::set_compact_strings(CompactStrings);
2541 
2542   // Initialize java_lang.System (needed before creating the thread)
2543   initialize_class(vmSymbols::java_lang_System(), CHECK);
2544   // The VM creates & returns objects of this class. Make sure it's initialized.
2545   initialize_class(vmSymbols::java_lang_Class(), CHECK);
2546   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
2547   Handle thread_group = create_initial_thread_group(CHECK);
2548   Universe::set_main_thread_group(thread_group());
2549   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
2550   create_initial_thread(thread_group, main_thread, CHECK);
2551 
2552   // The VM creates objects of this class.
2553   initialize_class(vmSymbols::java_lang_Module(), CHECK);
2554 
2555 #ifdef ASSERT
2556   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
2557   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
2558 #endif
2559 
2560   // initialize the hardware-specific constants needed by Unsafe
2561   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
2562   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
2563 
2564   // The VM preresolves methods to these classes. Make sure that they get initialized
2565   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
2566   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
2567 
2568   // Phase 1 of the system initialization in the library, java.lang.System class initialization
2569   call_initPhase1(CHECK);
2570 
2571   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
2572   // Some values are actually configure-time constants but some can be set via the jlink tool and
2573   // so must be read dynamically. We treat them all the same.
2574   InstanceKlass* ik = SystemDictionary::find_instance_klass(vmSymbols::java_lang_VersionProps(),
2575                                                             Handle(), Handle());
2576   {
2577     ResourceMark rm(main_thread);
2578     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
2579 
2580     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
2581 
2582     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
2583 
2584     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
2585 
2586     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
2587   }
2588 
2589   // an instance of OutOfMemory exception has been allocated earlier
2590   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
2591   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
2592   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
2593   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
2594   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
2595   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
2596   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
2597   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
2598 }
2599 
2600 void Threads::initialize_jsr292_core_classes(TRAPS) {
2601   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
2602 
2603   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
2604   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
2605   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
2606   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
2607 }
2608 
2609 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2610   extern void JDK_Version_init();
2611 
2612   // Preinitialize version info.
2613   VM_Version::early_initialize();
2614 
2615   // Check version
2616   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2617 
2618   // Initialize library-based TLS
2619   ThreadLocalStorage::init();
2620 
2621   // Initialize the output stream module
2622   ostream_init();
2623 
2624   // Process java launcher properties.
2625   Arguments::process_sun_java_launcher_properties(args);
2626 
2627   // Initialize the os module
2628   os::init();
2629 
2630   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
2631 
2632   // Record VM creation timing statistics
2633   TraceVmCreationTime create_vm_timer;
2634   create_vm_timer.start();
2635 
2636   // Initialize system properties.
2637   Arguments::init_system_properties();
2638 
2639   // So that JDK version can be used as a discriminator when parsing arguments
2640   JDK_Version_init();
2641 
2642   // Update/Initialize System properties after JDK version number is known
2643   Arguments::init_version_specific_system_properties();
2644 
2645   // Make sure to initialize log configuration *before* parsing arguments
2646   LogConfiguration::initialize(create_vm_timer.begin_time());
2647 
2648   // Parse arguments
2649   // Note: this internally calls os::init_container_support()
2650   jint parse_result = Arguments::parse(args);
2651   if (parse_result != JNI_OK) return parse_result;
2652 
2653   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
2654   MemTracker::initialize();
2655 
2656   os::init_before_ergo();
2657 
2658   jint ergo_result = Arguments::apply_ergo();
2659   if (ergo_result != JNI_OK) return ergo_result;
2660 
2661   // Final check of all ranges after ergonomics which may change values.
2662   if (!JVMFlagLimit::check_all_ranges()) {
2663     return JNI_EINVAL;
2664   }
2665 
2666   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
2667   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
2668   if (!constraint_result) {
2669     return JNI_EINVAL;
2670   }
2671 
2672   if (PauseAtStartup) {
2673     os::pause();
2674   }
2675 
2676   HOTSPOT_VM_INIT_BEGIN();
2677 
2678   // Timing (must come after argument parsing)
2679   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
2680 
2681   // Initialize the os module after parsing the args
2682   jint os_init_2_result = os::init_2();
2683   if (os_init_2_result != JNI_OK) return os_init_2_result;
2684 
2685 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
2686   // Initialize assert poison page mechanism.
2687   if (ShowRegistersOnAssert) {
2688     initialize_assert_poison();
2689   }
2690 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
2691 
2692   SafepointMechanism::initialize();
2693 
2694   jint adjust_after_os_result = Arguments::adjust_after_os();
2695   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
2696 
2697   // Initialize output stream logging
2698   ostream_init_log();
2699 
2700   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2701   // Must be before create_vm_init_agents()
2702   if (Arguments::init_libraries_at_startup()) {
2703     convert_vm_init_libraries_to_agents();
2704   }
2705 
2706   // Launch -agentlib/-agentpath and converted -Xrun agents
2707   if (Arguments::init_agents_at_startup()) {
2708     create_vm_init_agents();
2709   }
2710 
2711   // Initialize Threads state
2712   _number_of_threads = 0;
2713   _number_of_non_daemon_threads = 0;
2714 
2715   // Initialize global data structures and create system classes in heap
2716   vm_init_globals();
2717 
2718 #if INCLUDE_JVMCI
2719   if (JVMCICounterSize > 0) {
2720     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
2721     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
2722   } else {
2723     JavaThread::_jvmci_old_thread_counters = NULL;
2724   }
2725 #endif // INCLUDE_JVMCI
2726 
2727   // Initialize OopStorage for threadObj
2728   _thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
2729 
2730   // Attach the main thread to this os thread
2731   JavaThread* main_thread = new JavaThread();
2732   main_thread->set_thread_state(_thread_in_vm);
2733   main_thread->initialize_thread_current();
2734   // must do this before set_active_handles
2735   main_thread->record_stack_base_and_size();
2736   main_thread->register_thread_stack_with_NMT();
2737   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2738   MACOS_AARCH64_ONLY(main_thread->init_wx());
2739 
2740   if (!main_thread->set_as_starting_thread()) {
2741     vm_shutdown_during_initialization(
2742                                       "Failed necessary internal allocation. Out of swap space");
2743     main_thread->smr_delete();
2744     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2745     return JNI_ENOMEM;
2746   }
2747 
2748   // Enable guard page *after* os::create_main_thread(), otherwise it would
2749   // crash Linux VM, see notes in os_linux.cpp.
2750   main_thread->stack_overflow_state()->create_stack_guard_pages();
2751 
2752   // Initialize Java-Level synchronization subsystem
2753   ObjectMonitor::Initialize();
2754   ObjectSynchronizer::initialize();
2755 
2756   // Initialize global modules
2757   jint status = init_globals();
2758   if (status != JNI_OK) {
2759     main_thread->smr_delete();
2760     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2761     return status;
2762   }
2763 
2764   JFR_ONLY(Jfr::on_create_vm_1();)
2765 
2766   // Should be done after the heap is fully created
2767   main_thread->cache_global_variables();
2768 
2769   { MutexLocker mu(Threads_lock);
2770     Threads::add(main_thread);
2771   }
2772 
2773   // Any JVMTI raw monitors entered in onload will transition into
2774   // real raw monitor. VM is setup enough here for raw monitor enter.
2775   JvmtiExport::transition_pending_onload_raw_monitors();
2776 
2777   // Create the VMThread
2778   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
2779 
2780     VMThread::create();
2781     VMThread* vmthread = VMThread::vm_thread();
2782 
2783     if (!os::create_thread(vmthread, os::vm_thread)) {
2784       vm_exit_during_initialization("Cannot create VM thread. "
2785                                     "Out of system resources.");
2786     }
2787 
2788     // Wait for the VM thread to become ready, and VMThread::run to initialize
2789     // Monitors can have spurious returns, must always check another state flag
2790     {
2791       MonitorLocker ml(Notify_lock);
2792       os::start_thread(vmthread);
2793       while (!vmthread->is_running()) {
2794         ml.wait();
2795       }
2796     }
2797   }
2798 
2799   assert(Universe::is_fully_initialized(), "not initialized");
2800   if (VerifyDuringStartup) {
2801     // Make sure we're starting with a clean slate.
2802     VM_Verify verify_op;
2803     VMThread::execute(&verify_op);
2804   }
2805 
2806   // We need this to update the java.vm.info property in case any flags used
2807   // to initially define it have been changed. This is needed for both CDS
2808   // since UseSharedSpaces may be changed after java.vm.info
2809   // is initially computed. See Abstract_VM_Version::vm_info_string().
2810   // This update must happen before we initialize the java classes, but
2811   // after any initialization logic that might modify the flags.
2812   Arguments::update_vm_info_property(VM_Version::vm_info_string());
2813 
2814   JavaThread* THREAD = JavaThread::current(); // For exception macros.
2815   HandleMark hm(THREAD);
2816 
2817   // Always call even when there are not JVMTI environments yet, since environments
2818   // may be attached late and JVMTI must track phases of VM execution
2819   JvmtiExport::enter_early_start_phase();
2820 
2821   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2822   JvmtiExport::post_early_vm_start();
2823 
2824   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
2825 
2826   quicken_jni_functions();
2827 
2828   // No more stub generation allowed after that point.
2829   StubCodeDesc::freeze();
2830 
2831   // Set flag that basic initialization has completed. Used by exceptions and various
2832   // debug stuff, that does not work until all basic classes have been initialized.
2833   set_init_completed();
2834 
2835   LogConfiguration::post_initialize();
2836   Metaspace::post_initialize();
2837 
2838   HOTSPOT_VM_INIT_END();
2839 
2840   // record VM initialization completion time
2841 #if INCLUDE_MANAGEMENT
2842   Management::record_vm_init_completed();
2843 #endif // INCLUDE_MANAGEMENT
2844 
2845   // Signal Dispatcher needs to be started before VMInit event is posted
2846   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
2847 
2848   // Start Attach Listener if +StartAttachListener or it can't be started lazily
2849   if (!DisableAttachMechanism) {
2850     AttachListener::vm_start();
2851     if (StartAttachListener || AttachListener::init_at_startup()) {
2852       AttachListener::init();
2853     }
2854   }
2855 
2856   // Launch -Xrun agents
2857   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
2858   // back-end can launch with -Xdebug -Xrunjdwp.
2859   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
2860     create_vm_init_libraries();
2861   }
2862 
2863   Chunk::start_chunk_pool_cleaner_task();
2864 
2865   // Start the service thread
2866   // The service thread enqueues JVMTI deferred events and does various hashtable
2867   // and other cleanups.  Needs to start before the compilers start posting events.
2868   ServiceThread::initialize();
2869 
2870   // Start the monitor deflation thread:
2871   MonitorDeflationThread::initialize();
2872 
2873   // Start heap object statistics sampling
2874   HeapObjectStatistics::initialize();
2875 
2876   // initialize compiler(s)
2877 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
2878 #if INCLUDE_JVMCI
2879   bool force_JVMCI_intialization = false;
2880   if (EnableJVMCI) {
2881     // Initialize JVMCI eagerly when it is explicitly requested.
2882     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
2883     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
2884 
2885     if (!force_JVMCI_intialization) {
2886       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
2887       // compilations via JVMCI will not actually block until JVMCI is initialized.
2888       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
2889     }
2890   }
2891 #endif
2892   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
2893   // Postpone completion of compiler initialization to after JVMCI
2894   // is initialized to avoid timeouts of blocking compilations.
2895   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
2896     CompileBroker::compilation_init_phase2();
2897   }
2898 #endif
2899 
2900   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
2901   // It is done after compilers are initialized, because otherwise compilations of
2902   // signature polymorphic MH intrinsics can be missed
2903   // (see SystemDictionary::find_method_handle_intrinsic).
2904   initialize_jsr292_core_classes(CHECK_JNI_ERR);
2905 
2906   // This will initialize the module system.  Only java.base classes can be
2907   // loaded until phase 2 completes
2908   call_initPhase2(CHECK_JNI_ERR);
2909 
2910   JFR_ONLY(Jfr::on_create_vm_2();)
2911 
2912   // Always call even when there are not JVMTI environments yet, since environments
2913   // may be attached late and JVMTI must track phases of VM execution
2914   JvmtiExport::enter_start_phase();
2915 
2916   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2917   JvmtiExport::post_vm_start();
2918 
2919   // Final system initialization including security manager and system class loader
2920   call_initPhase3(CHECK_JNI_ERR);
2921 
2922   // cache the system and platform class loaders
2923   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
2924 
2925 #if INCLUDE_CDS
2926   // capture the module path info from the ModuleEntryTable
2927   ClassLoader::initialize_module_path(THREAD);
2928   if (HAS_PENDING_EXCEPTION) {
2929     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
2930     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
2931   }
2932 #endif
2933 
2934 #if INCLUDE_JVMCI
2935   if (force_JVMCI_intialization) {
2936     JVMCI::initialize_compiler(CHECK_JNI_ERR);
2937     CompileBroker::compilation_init_phase2();
2938   }
2939 #endif
2940 
2941   // Always call even when there are not JVMTI environments yet, since environments
2942   // may be attached late and JVMTI must track phases of VM execution
2943   JvmtiExport::enter_live_phase();
2944 
2945   // Make perfmemory accessible
2946   PerfMemory::set_accessible(true);
2947 
2948   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
2949   JvmtiExport::post_vm_initialized();
2950 
2951   JFR_ONLY(Jfr::on_create_vm_3();)
2952 
2953 #if INCLUDE_MANAGEMENT
2954   Management::initialize(THREAD);
2955 
2956   if (HAS_PENDING_EXCEPTION) {
2957     // management agent fails to start possibly due to
2958     // configuration problem and is responsible for printing
2959     // stack trace if appropriate. Simply exit VM.
2960     vm_exit(1);
2961   }
2962 #endif // INCLUDE_MANAGEMENT
2963 
2964   StatSampler::engage();
2965   if (CheckJNICalls)                  JniPeriodicChecker::engage();
2966 
2967 #if INCLUDE_RTM_OPT
2968   RTMLockingCounters::init();
2969 #endif
2970 
2971   call_postVMInitHook(THREAD);
2972   // The Java side of PostVMInitHook.run must deal with all
2973   // exceptions and provide means of diagnosis.
2974   if (HAS_PENDING_EXCEPTION) {
2975     CLEAR_PENDING_EXCEPTION;
2976   }
2977 
2978   {
2979     MutexLocker ml(PeriodicTask_lock);
2980     // Make sure the WatcherThread can be started by WatcherThread::start()
2981     // or by dynamic enrollment.
2982     WatcherThread::make_startable();
2983     // Start up the WatcherThread if there are any periodic tasks
2984     // NOTE:  All PeriodicTasks should be registered by now. If they
2985     //   aren't, late joiners might appear to start slowly (we might
2986     //   take a while to process their first tick).
2987     if (PeriodicTask::num_tasks() > 0) {
2988       WatcherThread::start();
2989     }
2990   }
2991 
2992   create_vm_timer.end();
2993 #ifdef ASSERT
2994   _vm_complete = true;
2995 #endif
2996 
2997   if (DumpSharedSpaces) {
2998     MetaspaceShared::preload_and_dump();
2999     ShouldNotReachHere();
3000   }
3001 
3002   return JNI_OK;
3003 }
3004 
3005 // type for the Agent_OnLoad and JVM_OnLoad entry points
3006 extern "C" {
3007   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3008 }
3009 // Find a command line agent library and return its entry point for
3010 //         -agentlib:  -agentpath:   -Xrun
3011 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3012 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3013                                     const char *on_load_symbols[],
3014                                     size_t num_symbol_entries) {
3015   OnLoadEntry_t on_load_entry = NULL;
3016   void *library = NULL;
3017 
3018   if (!agent->valid()) {
3019     char buffer[JVM_MAXPATHLEN];
3020     char ebuf[1024] = "";
3021     const char *name = agent->name();
3022     const char *msg = "Could not find agent library ";
3023 
3024     // First check to see if agent is statically linked into executable
3025     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3026       library = agent->os_lib();
3027     } else if (agent->is_absolute_path()) {
3028       library = os::dll_load(name, ebuf, sizeof ebuf);
3029       if (library == NULL) {
3030         const char *sub_msg = " in absolute path, with error: ";
3031         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3032         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3033         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3034         // If we can't find the agent, exit.
3035         vm_exit_during_initialization(buf, NULL);
3036         FREE_C_HEAP_ARRAY(char, buf);
3037       }
3038     } else {
3039       // Try to load the agent from the standard dll directory
3040       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3041                              name)) {
3042         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3043       }
3044       if (library == NULL) { // Try the library path directory.
3045         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3046           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3047         }
3048         if (library == NULL) {
3049           const char *sub_msg = " on the library path, with error: ";
3050           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3051 
3052           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3053                        strlen(ebuf) + strlen(sub_msg2) + 1;
3054           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3055           if (!agent->is_instrument_lib()) {
3056             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3057           } else {
3058             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
3059           }
3060           // If we can't find the agent, exit.
3061           vm_exit_during_initialization(buf, NULL);
3062           FREE_C_HEAP_ARRAY(char, buf);
3063         }
3064       }
3065     }
3066     agent->set_os_lib(library);
3067     agent->set_valid();
3068   }
3069 
3070   // Find the OnLoad function.
3071   on_load_entry =
3072     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3073                                                           false,
3074                                                           on_load_symbols,
3075                                                           num_symbol_entries));
3076   return on_load_entry;
3077 }
3078 
3079 // Find the JVM_OnLoad entry point
3080 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3081   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3082   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3083 }
3084 
3085 // Find the Agent_OnLoad entry point
3086 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3087   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3088   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3089 }
3090 
3091 // For backwards compatibility with -Xrun
3092 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3093 // treated like -agentpath:
3094 // Must be called before agent libraries are created
3095 void Threads::convert_vm_init_libraries_to_agents() {
3096   AgentLibrary* agent;
3097   AgentLibrary* next;
3098 
3099   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3100     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3101     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3102 
3103     // If there is an JVM_OnLoad function it will get called later,
3104     // otherwise see if there is an Agent_OnLoad
3105     if (on_load_entry == NULL) {
3106       on_load_entry = lookup_agent_on_load(agent);
3107       if (on_load_entry != NULL) {
3108         // switch it to the agent list -- so that Agent_OnLoad will be called,
3109         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3110         Arguments::convert_library_to_agent(agent);
3111       } else {
3112         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3113       }
3114     }
3115   }
3116 }
3117 
3118 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3119 // Invokes Agent_OnLoad
3120 // Called very early -- before JavaThreads exist
3121 void Threads::create_vm_init_agents() {
3122   extern struct JavaVM_ main_vm;
3123   AgentLibrary* agent;
3124 
3125   JvmtiExport::enter_onload_phase();
3126 
3127   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3128     // CDS dumping does not support native JVMTI agent.
3129     // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
3130     if (Arguments::is_dumping_archive()) {
3131       if(!agent->is_instrument_lib()) {
3132         vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
3133       } else if (!AllowArchivingWithJavaAgent) {
3134         vm_exit_during_cds_dumping(
3135           "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
3136       }
3137     }
3138 
3139     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3140 
3141     if (on_load_entry != NULL) {
3142       // Invoke the Agent_OnLoad function
3143       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3144       if (err != JNI_OK) {
3145         vm_exit_during_initialization("agent library failed to init", agent->name());
3146       }
3147     } else {
3148       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3149     }
3150   }
3151 
3152   JvmtiExport::enter_primordial_phase();
3153 }
3154 
3155 extern "C" {
3156   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3157 }
3158 
3159 void Threads::shutdown_vm_agents() {
3160   // Send any Agent_OnUnload notifications
3161   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3162   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3163   extern struct JavaVM_ main_vm;
3164   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3165 
3166     // Find the Agent_OnUnload function.
3167     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3168                                                    os::find_agent_function(agent,
3169                                                    false,
3170                                                    on_unload_symbols,
3171                                                    num_symbol_entries));
3172 
3173     // Invoke the Agent_OnUnload function
3174     if (unload_entry != NULL) {
3175       JavaThread* thread = JavaThread::current();
3176       ThreadToNativeFromVM ttn(thread);
3177       HandleMark hm(thread);
3178       (*unload_entry)(&main_vm);
3179     }
3180   }
3181 }
3182 
3183 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3184 // Invokes JVM_OnLoad
3185 void Threads::create_vm_init_libraries() {
3186   extern struct JavaVM_ main_vm;
3187   AgentLibrary* agent;
3188 
3189   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3190     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3191 
3192     if (on_load_entry != NULL) {
3193       // Invoke the JVM_OnLoad function
3194       JavaThread* thread = JavaThread::current();
3195       ThreadToNativeFromVM ttn(thread);
3196       HandleMark hm(thread);
3197       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3198       if (err != JNI_OK) {
3199         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3200       }
3201     } else {
3202       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3203     }
3204   }
3205 }
3206 
3207 
3208 // Last thread running calls java.lang.Shutdown.shutdown()
3209 void JavaThread::invoke_shutdown_hooks() {
3210   HandleMark hm(this);
3211 
3212   // We could get here with a pending exception, if so clear it now or
3213   // it will cause MetaspaceShared::link_shared_classes to
3214   // fail for dynamic dump.
3215   if (this->has_pending_exception()) {
3216     this->clear_pending_exception();
3217   }
3218 
3219 #if INCLUDE_CDS
3220   // Link all classes for dynamic CDS dumping before vm exit.
3221   // Same operation is being done in JVM_BeforeHalt for handling the
3222   // case where the application calls System.exit().
3223   if (DynamicArchive::should_dump_at_vm_exit()) {
3224     DynamicArchive::prepare_for_dump_at_exit();
3225   }
3226 #endif
3227 
3228   EXCEPTION_MARK;
3229   Klass* shutdown_klass =
3230     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3231                                       THREAD);
3232   if (shutdown_klass != NULL) {
3233     // SystemDictionary::resolve_or_null will return null if there was
3234     // an exception.  If we cannot load the Shutdown class, just don't
3235     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3236     // won't be run.  Note that if a shutdown hook was registered,
3237     // the Shutdown class would have already been loaded
3238     // (Runtime.addShutdownHook will load it).
3239     JavaValue result(T_VOID);
3240     JavaCalls::call_static(&result,
3241                            shutdown_klass,
3242                            vmSymbols::shutdown_name(),
3243                            vmSymbols::void_method_signature(),
3244                            THREAD);
3245   }
3246   CLEAR_PENDING_EXCEPTION;
3247 }
3248 
3249 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3250 // the program falls off the end of main(). Another VM exit path is through
3251 // vm_exit() when the program calls System.exit() to return a value or when
3252 // there is a serious error in VM. The two shutdown paths are not exactly
3253 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3254 // and VM_Exit op at VM level.
3255 //
3256 // Shutdown sequence:
3257 //   + Shutdown native memory tracking if it is on
3258 //   + Wait until we are the last non-daemon thread to execute
3259 //     <-- every thing is still working at this moment -->
3260 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3261 //        shutdown hooks
3262 //   + Call before_exit(), prepare for VM exit
3263 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3264 //        currently the only user of this mechanism is File.deleteOnExit())
3265 //      > stop StatSampler, watcher thread,
3266 //        post thread end and vm death events to JVMTI,
3267 //        stop signal thread
3268 //   + Call JavaThread::exit(), it will:
3269 //      > release JNI handle blocks, remove stack guard pages
3270 //      > remove this thread from Threads list
3271 //     <-- no more Java code from this thread after this point -->
3272 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3273 //     the compiler threads at safepoint
3274 //     <-- do not use anything that could get blocked by Safepoint -->
3275 //   + Disable tracing at JNI/JVM barriers
3276 //   + Set _vm_exited flag for threads that are still running native code
3277 //   + Call exit_globals()
3278 //      > deletes tty
3279 //      > deletes PerfMemory resources
3280 //   + Delete this thread
3281 //   + Return to caller
3282 
3283 void Threads::destroy_vm() {
3284   JavaThread* thread = JavaThread::current();
3285 
3286 #ifdef ASSERT
3287   _vm_complete = false;
3288 #endif
3289   // Wait until we are the last non-daemon thread to execute
3290   {
3291     MonitorLocker nu(Threads_lock);
3292     while (Threads::number_of_non_daemon_threads() > 1)
3293       // This wait should make safepoint checks, wait without a timeout.
3294       nu.wait(0);
3295   }
3296 
3297   EventShutdown e;
3298   if (e.should_commit()) {
3299     e.set_reason("No remaining non-daemon Java threads");
3300     e.commit();
3301   }
3302 
3303   // Hang forever on exit if we are reporting an error.
3304   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
3305     os::infinite_sleep();
3306   }
3307   os::wait_for_keypress_at_exit();
3308 
3309   // run Java level shutdown hooks
3310   thread->invoke_shutdown_hooks();
3311 
3312   before_exit(thread);
3313 
3314   thread->exit(true);
3315 
3316   // We are no longer on the main thread list but could still be in a
3317   // secondary list where another thread may try to interact with us.
3318   // So wait until all such interactions are complete before we bring
3319   // the VM to the termination safepoint. Normally this would be done
3320   // using thread->smr_delete() below where we delete the thread, but
3321   // we can't call that after the termination safepoint is active as
3322   // we will deadlock on the Threads_lock. Once all interactions are
3323   // complete it is safe to directly delete the thread at any time.
3324   ThreadsSMRSupport::wait_until_not_protected(thread);
3325 
3326   HeapObjectStatistics::shutdown();
3327 
3328   // Stop VM thread.
3329   {
3330     // 4945125 The vm thread comes to a safepoint during exit.
3331     // GC vm_operations can get caught at the safepoint, and the
3332     // heap is unparseable if they are caught. Grab the Heap_lock
3333     // to prevent this. The GC vm_operations will not be able to
3334     // queue until after the vm thread is dead. After this point,
3335     // we'll never emerge out of the safepoint before the VM exits.
3336     // Assert that the thread is terminated so that acquiring the
3337     // Heap_lock doesn't cause the terminated thread to participate in
3338     // the safepoint protocol.
3339 
3340     assert(thread->is_terminated(), "must be terminated here");
3341     MutexLocker ml(Heap_lock);
3342 
3343     VMThread::wait_for_vm_thread_exit();
3344     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3345     VMThread::destroy();
3346   }
3347 
3348   // Now, all Java threads are gone except daemon threads. Daemon threads
3349   // running Java code or in VM are stopped by the Safepoint. However,
3350   // daemon threads executing native code are still running.  But they
3351   // will be stopped at native=>Java/VM barriers. Note that we can't
3352   // simply kill or suspend them, as it is inherently deadlock-prone.
3353 
3354   VM_Exit::set_vm_exited();
3355 
3356   // Clean up ideal graph printers after the VMThread has started
3357   // the final safepoint which will block all the Compiler threads.
3358   // Note that this Thread has already logically exited so the
3359   // clean_up() function's use of a JavaThreadIteratorWithHandle
3360   // would be a problem except set_vm_exited() has remembered the
3361   // shutdown thread which is granted a policy exception.
3362 #if defined(COMPILER2) && !defined(PRODUCT)
3363   IdealGraphPrinter::clean_up();
3364 #endif
3365 
3366   notify_vm_shutdown();
3367 
3368   // exit_globals() will delete tty
3369   exit_globals();
3370 
3371   // Deleting the shutdown thread here is safe. See comment on
3372   // wait_until_not_protected() above.
3373   delete thread;
3374 
3375 #if INCLUDE_JVMCI
3376   if (JVMCICounterSize > 0) {
3377     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
3378   }
3379 #endif
3380 
3381   LogConfiguration::finalize();
3382 }
3383 
3384 
3385 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3386   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3387   return is_supported_jni_version(version);
3388 }
3389 
3390 
3391 jboolean Threads::is_supported_jni_version(jint version) {
3392   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3393   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3394   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3395   if (version == JNI_VERSION_1_8) return JNI_TRUE;
3396   if (version == JNI_VERSION_9) return JNI_TRUE;
3397   if (version == JNI_VERSION_10) return JNI_TRUE;
3398   return JNI_FALSE;
3399 }
3400 
3401 
3402 void Threads::add(JavaThread* p, bool force_daemon) {
3403   // The threads lock must be owned at this point
3404   assert(Threads_lock->owned_by_self(), "must have threads lock");
3405 
3406   BarrierSet::barrier_set()->on_thread_attach(p);
3407 
3408   // Once a JavaThread is added to the Threads list, smr_delete() has
3409   // to be used to delete it. Otherwise we can just delete it directly.
3410   p->set_on_thread_list();
3411 
3412   _number_of_threads++;
3413   oop threadObj = p->threadObj();
3414   bool daemon = true;
3415   // Bootstrapping problem: threadObj can be null for initial
3416   // JavaThread (or for threads attached via JNI)
3417   if ((!force_daemon) && !is_daemon((threadObj))) {
3418     _number_of_non_daemon_threads++;
3419     daemon = false;
3420   }
3421 
3422   ThreadService::add_thread(p, daemon);
3423 
3424   // Maintain fast thread list
3425   ThreadsSMRSupport::add_thread(p);
3426 
3427   // Increase the ObjectMonitor ceiling for the new thread.
3428   ObjectSynchronizer::inc_in_use_list_ceiling();
3429 
3430   // Possible GC point.
3431   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
3432 
3433   // Make new thread known to active EscapeBarrier
3434   EscapeBarrier::thread_added(p);
3435 }
3436 
3437 void Threads::remove(JavaThread* p, bool is_daemon) {
3438   // Extra scope needed for Thread_lock, so we can check
3439   // that we do not remove thread without safepoint code notice
3440   { MonitorLocker ml(Threads_lock);
3441 
3442     // BarrierSet state must be destroyed after the last thread transition
3443     // before the thread terminates. Thread transitions result in calls to
3444     // StackWatermarkSet::on_safepoint(), which performs GC processing,
3445     // requiring the GC state to be alive.
3446     BarrierSet::barrier_set()->on_thread_detach(p);
3447 
3448     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
3449 
3450     // Maintain fast thread list
3451     ThreadsSMRSupport::remove_thread(p);
3452 
3453     _number_of_threads--;
3454     if (!is_daemon) {
3455       _number_of_non_daemon_threads--;
3456 
3457       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3458       // on destroy_vm will wake up.
3459       if (number_of_non_daemon_threads() == 1) {
3460         ml.notify_all();
3461       }
3462     }
3463     ThreadService::remove_thread(p, is_daemon);
3464 
3465     // Make sure that safepoint code disregard this thread. This is needed since
3466     // the thread might mess around with locks after this point. This can cause it
3467     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3468     // of this thread since it is removed from the queue.
3469     p->set_terminated(JavaThread::_thread_terminated);
3470 
3471     // Notify threads waiting in EscapeBarriers
3472     EscapeBarrier::thread_removed(p);
3473   } // unlock Threads_lock
3474 
3475   // Reduce the ObjectMonitor ceiling for the exiting thread.
3476   ObjectSynchronizer::dec_in_use_list_ceiling();
3477 
3478   // Since Events::log uses a lock, we grab it outside the Threads_lock
3479   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
3480 }
3481 
3482 // Operations on the Threads list for GC.  These are not explicitly locked,
3483 // but the garbage collector must provide a safe context for them to run.
3484 // In particular, these things should never be called when the Threads_lock
3485 // is held by some other thread. (Note: the Safepoint abstraction also
3486 // uses the Threads_lock to guarantee this property. It also makes sure that
3487 // all threads gets blocked when exiting or starting).
3488 
3489 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3490   ALL_JAVA_THREADS(p) {
3491     p->oops_do(f, cf);
3492   }
3493   VMThread::vm_thread()->oops_do(f, cf);
3494 }
3495 
3496 void Threads::change_thread_claim_token() {
3497   if (++_thread_claim_token == 0) {
3498     // On overflow of the token counter, there is a risk of future
3499     // collisions between a new global token value and a stale token
3500     // for a thread, because not all iterations visit all threads.
3501     // (Though it's pretty much a theoretical concern for non-trivial
3502     // token counter sizes.)  To deal with the possibility, reset all
3503     // the thread tokens to zero on global token overflow.
3504     struct ResetClaims : public ThreadClosure {
3505       virtual void do_thread(Thread* t) {
3506         t->claim_threads_do(false, 0);
3507       }
3508     } reset_claims;
3509     Threads::threads_do(&reset_claims);
3510     // On overflow, update the global token to non-zero, to
3511     // avoid the special "never claimed" initial thread value.
3512     _thread_claim_token = 1;
3513   }
3514 }
3515 
3516 #ifdef ASSERT
3517 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
3518   const uintx token = t->threads_do_token();
3519   assert(token == expected,
3520          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
3521          UINTX_FORMAT, kind, p2i(t), token, expected);
3522 }
3523 
3524 void Threads::assert_all_threads_claimed() {
3525   ALL_JAVA_THREADS(p) {
3526     assert_thread_claimed("Thread", p, _thread_claim_token);
3527   }
3528   assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
3529 }
3530 #endif // ASSERT
3531 
3532 class ParallelOopsDoThreadClosure : public ThreadClosure {
3533 private:
3534   OopClosure* _f;
3535   CodeBlobClosure* _cf;
3536 public:
3537   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
3538   void do_thread(Thread* t) {
3539     t->oops_do(_f, _cf);
3540   }
3541 };
3542 
3543 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
3544   ParallelOopsDoThreadClosure tc(f, cf);
3545   possibly_parallel_threads_do(is_par, &tc);
3546 }
3547 
3548 void Threads::metadata_do(MetadataClosure* f) {
3549   ALL_JAVA_THREADS(p) {
3550     p->metadata_do(f);
3551   }
3552 }
3553 
3554 class ThreadHandlesClosure : public ThreadClosure {
3555   void (*_f)(Metadata*);
3556  public:
3557   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
3558   virtual void do_thread(Thread* thread) {
3559     thread->metadata_handles_do(_f);
3560   }
3561 };
3562 
3563 void Threads::metadata_handles_do(void f(Metadata*)) {
3564   // Only walk the Handles in Thread.
3565   ThreadHandlesClosure handles_closure(f);
3566   threads_do(&handles_closure);
3567 }
3568 
3569 // Get count Java threads that are waiting to enter the specified monitor.
3570 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
3571                                                          int count,
3572                                                          address monitor) {
3573   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3574 
3575   int i = 0;
3576   for (JavaThread* p : *t_list) {
3577     if (!p->can_call_java()) continue;
3578 
3579     // The first stage of async deflation does not affect any field
3580     // used by this comparison so the ObjectMonitor* is usable here.
3581     address pending = (address)p->current_pending_monitor();
3582     if (pending == monitor) {             // found a match
3583       if (i < count) result->append(p);   // save the first count matches
3584       i++;
3585     }
3586   }
3587 
3588   return result;
3589 }
3590 
3591 
3592 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
3593                                                       address owner) {
3594   // NULL owner means not locked so we can skip the search
3595   if (owner == NULL) return NULL;
3596 
3597   for (JavaThread* p : *t_list) {
3598     // first, see if owner is the address of a Java thread
3599     if (owner == (address)p) return p;
3600   }
3601 
3602   // Cannot assert on lack of success here since this function may be
3603   // used by code that is trying to report useful problem information
3604   // like deadlock detection.
3605   if (UseHeavyMonitors) return NULL;
3606 
3607   // If we didn't find a matching Java thread and we didn't force use of
3608   // heavyweight monitors, then the owner is the stack address of the
3609   // Lock Word in the owning Java thread's stack.
3610   //
3611   JavaThread* the_owner = NULL;
3612   for (JavaThread* q : *t_list) {
3613     if (q->is_lock_owned(owner)) {
3614       the_owner = q;
3615       break;
3616     }
3617   }
3618 
3619   // cannot assert on lack of success here; see above comment
3620   return the_owner;
3621 }
3622 
3623 class PrintOnClosure : public ThreadClosure {
3624 private:
3625   outputStream* _st;
3626 
3627 public:
3628   PrintOnClosure(outputStream* st) :
3629       _st(st) {}
3630 
3631   virtual void do_thread(Thread* thread) {
3632     if (thread != NULL) {
3633       thread->print_on(_st);
3634       _st->cr();
3635     }
3636   }
3637 };
3638 
3639 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3640 void Threads::print_on(outputStream* st, bool print_stacks,
3641                        bool internal_format, bool print_concurrent_locks,
3642                        bool print_extended_info) {
3643   char buf[32];
3644   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
3645 
3646   st->print_cr("Full thread dump %s (%s %s):",
3647                VM_Version::vm_name(),
3648                VM_Version::vm_release(),
3649                VM_Version::vm_info_string());
3650   st->cr();
3651 
3652 #if INCLUDE_SERVICES
3653   // Dump concurrent locks
3654   ConcurrentLocksDump concurrent_locks;
3655   if (print_concurrent_locks) {
3656     concurrent_locks.dump_at_safepoint();
3657   }
3658 #endif // INCLUDE_SERVICES
3659 
3660   ThreadsSMRSupport::print_info_on(st);
3661   st->cr();
3662 
3663   ALL_JAVA_THREADS(p) {
3664     ResourceMark rm;
3665     p->print_on(st, print_extended_info);
3666     if (print_stacks) {
3667       if (internal_format) {
3668         p->trace_stack();
3669       } else {
3670         p->print_stack_on(st);
3671       }
3672     }
3673     st->cr();
3674 #if INCLUDE_SERVICES
3675     if (print_concurrent_locks) {
3676       concurrent_locks.print_locks_on(p, st);
3677     }
3678 #endif // INCLUDE_SERVICES
3679   }
3680 
3681   PrintOnClosure cl(st);
3682   cl.do_thread(VMThread::vm_thread());
3683   Universe::heap()->gc_threads_do(&cl);
3684   if (StringDedup::is_enabled()) {
3685     StringDedup::threads_do(&cl);
3686   }
3687   cl.do_thread(WatcherThread::watcher_thread());
3688   cl.do_thread(AsyncLogWriter::instance());
3689 
3690   st->flush();
3691 }
3692 
3693 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
3694                              int buflen, bool* found_current) {
3695   if (this_thread != NULL) {
3696     bool is_current = (current == this_thread);
3697     *found_current = *found_current || is_current;
3698     st->print("%s", is_current ? "=>" : "  ");
3699 
3700     st->print(PTR_FORMAT, p2i(this_thread));
3701     st->print(" ");
3702     this_thread->print_on_error(st, buf, buflen);
3703     st->cr();
3704   }
3705 }
3706 
3707 class PrintOnErrorClosure : public ThreadClosure {
3708   outputStream* _st;
3709   Thread* _current;
3710   char* _buf;
3711   int _buflen;
3712   bool* _found_current;
3713  public:
3714   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
3715                       int buflen, bool* found_current) :
3716    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
3717 
3718   virtual void do_thread(Thread* thread) {
3719     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
3720   }
3721 };
3722 
3723 // Threads::print_on_error() is called by fatal error handler. It's possible
3724 // that VM is not at safepoint and/or current thread is inside signal handler.
3725 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3726 // memory (even in resource area), it might deadlock the error handler.
3727 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
3728                              int buflen) {
3729   ThreadsSMRSupport::print_info_on(st);
3730   st->cr();
3731 
3732   bool found_current = false;
3733   st->print_cr("Java Threads: ( => current thread )");
3734   ALL_JAVA_THREADS(thread) {
3735     print_on_error(thread, st, current, buf, buflen, &found_current);
3736   }
3737   st->cr();
3738 
3739   st->print_cr("Other Threads:");
3740   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
3741   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
3742   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
3743 
3744   if (Universe::heap() != NULL) {
3745     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3746     Universe::heap()->gc_threads_do(&print_closure);
3747   }
3748 
3749   if (StringDedup::is_enabled()) {
3750     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3751     StringDedup::threads_do(&print_closure);
3752   }
3753 
3754   if (!found_current) {
3755     st->cr();
3756     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
3757     current->print_on_error(st, buf, buflen);
3758     st->cr();
3759   }
3760   st->cr();
3761 
3762   st->print_cr("Threads with active compile tasks:");
3763   print_threads_compiling(st, buf, buflen);
3764 }
3765 
3766 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
3767   ALL_JAVA_THREADS(thread) {
3768     if (thread->is_Compiler_thread()) {
3769       CompilerThread* ct = (CompilerThread*) thread;
3770 
3771       // Keep task in local variable for NULL check.
3772       // ct->_task might be set to NULL by concurring compiler thread
3773       // because it completed the compilation. The task is never freed,
3774       // though, just returned to a free list.
3775       CompileTask* task = ct->task();
3776       if (task != NULL) {
3777         thread->print_name_on_error(st, buf, buflen);
3778         st->print("  ");
3779         task->print(st, NULL, short_form, true);
3780       }
3781     }
3782   }
3783 }
3784 
3785 
3786 // Ad-hoc mutual exclusion primitives: SpinLock
3787 //
3788 // We employ SpinLocks _only for low-contention, fixed-length
3789 // short-duration critical sections where we're concerned
3790 // about native mutex_t or HotSpot Mutex:: latency.
3791 //
3792 // TODO-FIXME: ListLock should be of type SpinLock.
3793 // We should make this a 1st-class type, integrated into the lock
3794 // hierarchy as leaf-locks.  Critically, the SpinLock structure
3795 // should have sufficient padding to avoid false-sharing and excessive
3796 // cache-coherency traffic.
3797 
3798 
3799 typedef volatile int SpinLockT;
3800 
3801 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
3802   if (Atomic::cmpxchg(adr, 0, 1) == 0) {
3803     return;   // normal fast-path return
3804   }
3805 
3806   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
3807   int ctr = 0;
3808   int Yields = 0;
3809   for (;;) {
3810     while (*adr != 0) {
3811       ++ctr;
3812       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
3813         if (Yields > 5) {
3814           os::naked_short_sleep(1);
3815         } else {
3816           os::naked_yield();
3817           ++Yields;
3818         }
3819       } else {
3820         SpinPause();
3821       }
3822     }
3823     if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
3824   }
3825 }
3826 
3827 void Thread::SpinRelease(volatile int * adr) {
3828   assert(*adr != 0, "invariant");
3829   OrderAccess::fence();      // guarantee at least release consistency.
3830   // Roach-motel semantics.
3831   // It's safe if subsequent LDs and STs float "up" into the critical section,
3832   // but prior LDs and STs within the critical section can't be allowed
3833   // to reorder or float past the ST that releases the lock.
3834   // Loads and stores in the critical section - which appear in program
3835   // order before the store that releases the lock - must also appear
3836   // before the store that releases the lock in memory visibility order.
3837   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
3838   // the ST of 0 into the lock-word which releases the lock, so fence
3839   // more than covers this on all platforms.
3840   *adr = 0;
3841 }
3842 
3843 
3844 void Threads::verify() {
3845   ALL_JAVA_THREADS(p) {
3846     p->verify();
3847   }
3848   VMThread* thread = VMThread::vm_thread();
3849   if (thread != NULL) thread->verify();
3850 }
3851 
3852 #ifndef PRODUCT
3853 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
3854    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
3855 }
3856 #endif
3857 
3858 // Helper function to create the java.lang.Thread object for a
3859 // VM-internal thread. The thread will have the given name, be
3860 // part of the System ThreadGroup and if is_visible is true will be
3861 // discoverable via the system ThreadGroup.
3862 Handle JavaThread::create_system_thread_object(const char* name,
3863                                                bool is_visible, TRAPS) {
3864   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
3865 
3866   // Initialize thread_oop to put it into the system threadGroup.
3867   // This is done by calling the Thread(ThreadGroup tg, String name)
3868   // constructor, which adds the new thread to the group as an unstarted
3869   // thread.
3870   Handle thread_group(THREAD, Universe::system_thread_group());
3871   Handle thread_oop =
3872     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
3873                                       vmSymbols::threadgroup_string_void_signature(),
3874                                       thread_group,
3875                                       string,
3876                                       CHECK_NH);
3877 
3878   // If the Thread is intended to be visible then we have to mimic what
3879   // Thread.start() would do, by adding it to its ThreadGroup: tg.add(t).
3880   if (is_visible) {
3881     Klass* group = vmClasses::ThreadGroup_klass();
3882     JavaValue result(T_VOID);
3883     JavaCalls::call_special(&result,
3884                             thread_group,
3885                             group,
3886                             vmSymbols::add_method_name(),
3887                             vmSymbols::thread_void_signature(),
3888                             thread_oop,
3889                             CHECK_NH);
3890   }
3891 
3892   return thread_oop;
3893 }
3894 
3895 // Starts the target JavaThread as a daemon of the given priority, and
3896 // bound to the given java.lang.Thread instance.
3897 // The Threads_lock is held for the duration.
3898 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
3899                                        Handle thread_oop, ThreadPriority prio) {
3900 
3901   assert(target->osthread() != NULL, "target thread is not properly initialized");
3902 
3903   MutexLocker mu(current, Threads_lock);
3904 
3905   // Initialize the fields of the thread_oop first.
3906 
3907   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
3908 
3909   if (prio != NoPriority) {
3910     java_lang_Thread::set_priority(thread_oop(), prio);
3911     // Note: we don't call os::set_priority here. Possibly we should,
3912     // else all threads should call it themselves when they first run.
3913   }
3914 
3915   java_lang_Thread::set_daemon(thread_oop());
3916 
3917   // Now bind the thread_oop to the target JavaThread.
3918   target->set_threadObj(thread_oop());
3919 
3920   Threads::add(target); // target is now visible for safepoint/handshake
3921   Thread::start(target);
3922 }
3923 
3924 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
3925   // At this point it may be possible that no osthread was created for the
3926   // JavaThread due to lack of resources. However, since this must work
3927   // for critical system threads just check and abort if this fails.
3928   if (thread->osthread() == nullptr) {
3929     // This isn't really an OOM condition, but historically this is what
3930     // we report.
3931     vm_exit_during_initialization("java.lang.OutOfMemoryError",
3932                                   os::native_thread_creation_failed_msg());
3933   }
3934 }