1 /*
   2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "jvm.h"
  28 #include "cds/dynamicArchive.hpp"
  29 #include "cds/metaspaceShared.hpp"
  30 #include "classfile/classLoader.hpp"
  31 #include "classfile/javaClasses.hpp"
  32 #include "classfile/javaThreadStatus.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmClasses.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "code/codeCache.hpp"
  37 #include "code/scopeDesc.hpp"
  38 #include "compiler/compileBroker.hpp"
  39 #include "compiler/compileTask.hpp"
  40 #include "compiler/compilerThread.hpp"
  41 #include "gc/shared/barrierSet.hpp"
  42 #include "gc/shared/collectedHeap.hpp"
  43 #include "gc/shared/gcId.hpp"
  44 #include "gc/shared/gcLocker.inline.hpp"
  45 #include "gc/shared/gcVMOperations.hpp"
  46 #include "gc/shared/oopStorage.hpp"
  47 #include "gc/shared/oopStorageSet.hpp"
  48 #include "gc/shared/stringdedup/stringDedup.hpp"
  49 #include "gc/shared/tlab_globals.hpp"
  50 #include "interpreter/interpreter.hpp"
  51 #include "interpreter/linkResolver.hpp"
  52 #include "interpreter/oopMapCache.hpp"
  53 #include "jfr/jfrEvents.hpp"
  54 #include "jvmtifiles/jvmtiEnv.hpp"
  55 #include "logging/log.hpp"
  56 #include "logging/logAsyncWriter.hpp"
  57 #include "logging/logConfiguration.hpp"
  58 #include "logging/logStream.hpp"
  59 #include "memory/allocation.inline.hpp"
  60 #include "memory/iterator.hpp"
  61 #include "memory/oopFactory.hpp"
  62 #include "memory/resourceArea.hpp"
  63 #include "memory/universe.hpp"
  64 #include "oops/access.inline.hpp"
  65 #include "oops/instanceKlass.hpp"
  66 #include "oops/klass.inline.hpp"
  67 #include "oops/objArrayOop.hpp"
  68 #include "oops/oop.inline.hpp"
  69 #include "oops/oopHandle.inline.hpp"
  70 #include "oops/symbol.hpp"
  71 #include "oops/typeArrayOop.inline.hpp"
  72 #include "oops/verifyOopClosure.hpp"
  73 #include "prims/jvm_misc.hpp"
  74 #include "prims/jvmtiDeferredUpdates.hpp"
  75 #include "prims/jvmtiExport.hpp"
  76 #include "prims/jvmtiThreadState.hpp"
  77 #include "runtime/arguments.hpp"
  78 #include "runtime/atomic.hpp"
  79 #include "runtime/fieldDescriptor.inline.hpp"
  80 #include "runtime/flags/jvmFlagLimit.hpp"
  81 #include "runtime/deoptimization.hpp"
  82 #include "runtime/frame.inline.hpp"
  83 #include "runtime/handles.inline.hpp"
  84 #include "runtime/handshake.hpp"
  85 #include "runtime/init.hpp"
  86 #include "runtime/interfaceSupport.inline.hpp"
  87 #include "runtime/java.hpp"
  88 #include "runtime/javaCalls.hpp"
  89 #include "runtime/jniHandles.inline.hpp"
  90 #include "runtime/jniPeriodicChecker.hpp"
  91 #include "runtime/monitorDeflationThread.hpp"
  92 #include "runtime/mutexLocker.hpp"
  93 #include "runtime/nonJavaThread.hpp"
  94 #include "runtime/objectMonitor.hpp"
  95 #include "runtime/orderAccess.hpp"
  96 #include "runtime/osThread.hpp"
  97 #include "runtime/safepoint.hpp"
  98 #include "runtime/safepointMechanism.inline.hpp"
  99 #include "runtime/safepointVerifiers.hpp"
 100 #include "runtime/serviceThread.hpp"
 101 #include "runtime/sharedRuntime.hpp"
 102 #include "runtime/stackFrameStream.inline.hpp"
 103 #include "runtime/stackWatermarkSet.hpp"
 104 #include "runtime/statSampler.hpp"
 105 #include "runtime/task.hpp"
 106 #include "runtime/thread.inline.hpp"
 107 #include "runtime/threadCritical.hpp"
 108 #include "runtime/threadSMR.inline.hpp"
 109 #include "runtime/threadStatisticalInfo.hpp"
 110 #include "runtime/threadWXSetters.inline.hpp"
 111 #include "runtime/timer.hpp"
 112 #include "runtime/timerTrace.hpp"
 113 #include "runtime/vframe.inline.hpp"
 114 #include "runtime/vframeArray.hpp"
 115 #include "runtime/vframe_hp.hpp"
 116 #include "runtime/vmThread.hpp"
 117 #include "runtime/vmOperations.hpp"
 118 #include "runtime/vm_version.hpp"
 119 #include "services/attachListener.hpp"
 120 #include "services/management.hpp"
 121 #include "services/memTracker.hpp"
 122 #include "services/threadService.hpp"
 123 #include "utilities/align.hpp"
 124 #include "utilities/copy.hpp"
 125 #include "utilities/defaultStream.hpp"
 126 #include "utilities/dtrace.hpp"
 127 #include "utilities/events.hpp"
 128 #include "utilities/macros.hpp"
 129 #include "utilities/preserveException.hpp"
 130 #include "utilities/spinYield.hpp"
 131 #include "utilities/vmError.hpp"
 132 #if INCLUDE_JVMCI
 133 #include "jvmci/jvmci.hpp"
 134 #include "jvmci/jvmciEnv.hpp"
 135 #endif
 136 #ifdef COMPILER1
 137 #include "c1/c1_Compiler.hpp"
 138 #endif
 139 #ifdef COMPILER2
 140 #include "opto/c2compiler.hpp"
 141 #include "opto/idealGraphPrinter.hpp"
 142 #endif
 143 #if INCLUDE_RTM_OPT
 144 #include "runtime/rtmLocking.hpp"
 145 #endif
 146 #if INCLUDE_JFR
 147 #include "jfr/jfr.hpp"
 148 #endif
 149 
 150 // Initialization after module runtime initialization
 151 void universe_post_module_init();  // must happen after call_initPhase2
 152 
 153 #ifdef DTRACE_ENABLED
 154 
 155 // Only bother with this argument setup if dtrace is available
 156 
 157   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 158   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 159 
 160   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 161     {                                                                      \
 162       ResourceMark rm(this);                                               \
 163       int len = 0;                                                         \
 164       const char* name = (javathread)->name();                             \
 165       len = strlen(name);                                                  \
 166       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 167         (char *) name, len,                                                \
 168         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 169         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 170         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 171     }
 172 
 173 #else //  ndef DTRACE_ENABLED
 174 
 175   #define DTRACE_THREAD_PROBE(probe, javathread)
 176 
 177 #endif // ndef DTRACE_ENABLED
 178 
 179 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 180 // Current thread is maintained as a thread-local variable
 181 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
 182 #endif
 183 
 184 // ======= Thread ========
 185 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 186   return throw_excpt ? AllocateHeap(size, flags, CURRENT_PC)
 187                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 188 }
 189 
 190 void Thread::operator delete(void* p) {
 191   FreeHeap(p);
 192 }
 193 
 194 void JavaThread::smr_delete() {
 195   if (_on_thread_list) {
 196     ThreadsSMRSupport::smr_delete(this);
 197   } else {
 198     delete this;
 199   }
 200 }
 201 
 202 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 203 // JavaThread
 204 
 205 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
 206 
 207 Thread::Thread() {
 208 
 209   DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
 210 
 211   // stack and get_thread
 212   set_stack_base(NULL);
 213   set_stack_size(0);
 214   set_lgrp_id(-1);
 215   DEBUG_ONLY(clear_suspendible_thread();)
 216 
 217   // allocated data structures
 218   set_osthread(NULL);
 219   set_resource_area(new (mtThread)ResourceArea());
 220   DEBUG_ONLY(_current_resource_mark = NULL;)
 221   set_handle_area(new (mtThread) HandleArea(NULL));
 222   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
 223   set_active_handles(NULL);
 224   set_free_handle_block(NULL);
 225   set_last_handle_mark(NULL);
 226   DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
 227 
 228   // Initial value of zero ==> never claimed.
 229   _threads_do_token = 0;
 230   _threads_hazard_ptr = NULL;
 231   _threads_list_ptr = NULL;
 232   _nested_threads_hazard_ptr_cnt = 0;
 233   _rcu_counter = 0;
 234 
 235   // the handle mark links itself to last_handle_mark
 236   new HandleMark(this);
 237 
 238   // plain initialization
 239   debug_only(_owned_locks = NULL;)
 240   NOT_PRODUCT(_skip_gcalot = false;)
 241   _jvmti_env_iteration_count = 0;
 242   set_allocated_bytes(0);
 243   _current_pending_raw_monitor = NULL;
 244 
 245   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 246   _hashStateX = os::random();
 247   _hashStateY = 842502087;
 248   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 249   _hashStateW = 273326509;
 250 
 251   // Many of the following fields are effectively final - immutable
 252   // Note that nascent threads can't use the Native Monitor-Mutex
 253   // construct until the _MutexEvent is initialized ...
 254   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 255   // we might instead use a stack of ParkEvents that we could provision on-demand.
 256   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 257   // and ::Release()
 258   _ParkEvent   = ParkEvent::Allocate(this);
 259 
 260 #ifdef CHECK_UNHANDLED_OOPS
 261   if (CheckUnhandledOops) {
 262     _unhandled_oops = new UnhandledOops(this);
 263   }
 264 #endif // CHECK_UNHANDLED_OOPS
 265 
 266   // Notify the barrier set that a thread is being created. The initial
 267   // thread is created before the barrier set is available.  The call to
 268   // BarrierSet::on_thread_create() for this thread is therefore deferred
 269   // to BarrierSet::set_barrier_set().
 270   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 271   if (barrier_set != NULL) {
 272     barrier_set->on_thread_create(this);
 273   } else {
 274     // Only the main thread should be created before the barrier set
 275     // and that happens just before Thread::current is set. No other thread
 276     // can attach as the VM is not created yet, so they can't execute this code.
 277     // If the main thread creates other threads before the barrier set that is an error.
 278     assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
 279   }
 280 
 281   MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
 282 }
 283 
 284 void Thread::initialize_tlab() {
 285   if (UseTLAB) {
 286     tlab().initialize();
 287   }
 288 }
 289 
 290 void Thread::initialize_thread_current() {
 291 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 292   assert(_thr_current == NULL, "Thread::current already initialized");
 293   _thr_current = this;
 294 #endif
 295   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 296   ThreadLocalStorage::set_thread(this);
 297   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 298 }
 299 
 300 void Thread::clear_thread_current() {
 301   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 302 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 303   _thr_current = NULL;
 304 #endif
 305   ThreadLocalStorage::set_thread(NULL);
 306 }
 307 
 308 void Thread::record_stack_base_and_size() {
 309   // Note: at this point, Thread object is not yet initialized. Do not rely on
 310   // any members being initialized. Do not rely on Thread::current() being set.
 311   // If possible, refrain from doing anything which may crash or assert since
 312   // quite probably those crash dumps will be useless.
 313   set_stack_base(os::current_stack_base());
 314   set_stack_size(os::current_stack_size());
 315 
 316   // Set stack limits after thread is initialized.
 317   if (is_Java_thread()) {
 318     JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
 319   }
 320 }
 321 
 322 #if INCLUDE_NMT
 323 void Thread::register_thread_stack_with_NMT() {
 324   MemTracker::record_thread_stack(stack_end(), stack_size());
 325 }
 326 
 327 void Thread::unregister_thread_stack_with_NMT() {
 328   MemTracker::release_thread_stack(stack_end(), stack_size());
 329 }
 330 #endif // INCLUDE_NMT
 331 
 332 void Thread::call_run() {
 333   DEBUG_ONLY(_run_state = CALL_RUN;)
 334 
 335   // At this point, Thread object should be fully initialized and
 336   // Thread::current() should be set.
 337 
 338   assert(Thread::current_or_null() != NULL, "current thread is unset");
 339   assert(Thread::current_or_null() == this, "current thread is wrong");
 340 
 341   // Perform common initialization actions
 342 
 343   register_thread_stack_with_NMT();
 344 
 345   MACOS_AARCH64_ONLY(this->init_wx());
 346 
 347   JFR_ONLY(Jfr::on_thread_start(this);)
 348 
 349   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 350     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 351     os::current_thread_id(), p2i(stack_end()),
 352     p2i(stack_base()), stack_size()/1024);
 353 
 354   // Perform <ChildClass> initialization actions
 355   DEBUG_ONLY(_run_state = PRE_RUN;)
 356   this->pre_run();
 357 
 358   // Invoke <ChildClass>::run()
 359   DEBUG_ONLY(_run_state = RUN;)
 360   this->run();
 361   // Returned from <ChildClass>::run(). Thread finished.
 362 
 363   // Perform common tear-down actions
 364 
 365   assert(Thread::current_or_null() != NULL, "current thread is unset");
 366   assert(Thread::current_or_null() == this, "current thread is wrong");
 367 
 368   // Perform <ChildClass> tear-down actions
 369   DEBUG_ONLY(_run_state = POST_RUN;)
 370   this->post_run();
 371 
 372   // Note: at this point the thread object may already have deleted itself,
 373   // so from here on do not dereference *this*. Not all thread types currently
 374   // delete themselves when they terminate. But no thread should ever be deleted
 375   // asynchronously with respect to its termination - that is what _run_state can
 376   // be used to check.
 377 
 378   assert(Thread::current_or_null() == NULL, "current thread still present");
 379 }
 380 
 381 Thread::~Thread() {
 382 
 383   // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
 384   // get started due to errors etc. Any active thread should at least reach post_run
 385   // before it is deleted (usually in post_run()).
 386   assert(_run_state == PRE_CALL_RUN ||
 387          _run_state == POST_RUN, "Active Thread deleted before post_run(): "
 388          "_run_state=%d", (int)_run_state);
 389 
 390   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 391   // set might not be available if we encountered errors during bootstrapping.
 392   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 393   if (barrier_set != NULL) {
 394     barrier_set->on_thread_destroy(this);
 395   }
 396 
 397   // deallocate data structures
 398   delete resource_area();
 399   // since the handle marks are using the handle area, we have to deallocated the root
 400   // handle mark before deallocating the thread's handle area,
 401   assert(last_handle_mark() != NULL, "check we have an element");
 402   delete last_handle_mark();
 403   assert(last_handle_mark() == NULL, "check we have reached the end");
 404 
 405   ParkEvent::Release(_ParkEvent);
 406   // Set to NULL as a termination indicator for has_terminated().
 407   Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
 408 
 409   delete handle_area();
 410   delete metadata_handles();
 411 
 412   // osthread() can be NULL, if creation of thread failed.
 413   if (osthread() != NULL) os::free_thread(osthread());
 414 
 415   // Clear Thread::current if thread is deleting itself and it has not
 416   // already been done. This must be done before the memory is deallocated.
 417   // Needed to ensure JNI correctly detects non-attached threads.
 418   if (this == Thread::current_or_null()) {
 419     Thread::clear_thread_current();
 420   }
 421 
 422   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 423 }
 424 
 425 #ifdef ASSERT
 426 // A JavaThread is considered dangling if it not handshake-safe with respect to
 427 // the current thread, it is not on a ThreadsList, or not at safepoint.
 428 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 429   assert(!thread->is_Java_thread() ||
 430          JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
 431          !JavaThread::cast(thread)->on_thread_list() ||
 432          SafepointSynchronize::is_at_safepoint() ||
 433          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
 434          "possibility of dangling Thread pointer");
 435 }
 436 #endif
 437 
 438 // Is the target JavaThread protected by the calling Thread
 439 // or by some other mechanism:
 440 bool Thread::is_JavaThread_protected(const JavaThread* p) {
 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 (p->osthread() == NULL || p->osthread()->get_state() <= INITIALIZED) {
 452     return true;
 453   }
 454 
 455   // Now make the simple checks based on who the caller is:
 456   Thread* current_thread = Thread::current();
 457   if (current_thread == p || Threads_lock->owner() == current_thread) {
 458     // Target JavaThread is self or calling thread owns the Threads_lock.
 459     // Second check is the same as Threads_lock->owner_is_self(),
 460     // but we already have the current thread so check directly.
 461     return true;
 462   }
 463 
 464   // Check the ThreadsLists associated with the calling thread (if any)
 465   // to see if one of them protects the target JavaThread:
 466   for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
 467        stlp != NULL; stlp = stlp->previous()) {
 468     if (stlp->list()->includes(p)) {
 469       // The target JavaThread is protected by this ThreadsList:
 470       return true;
 471     }
 472   }
 473 
 474   // Use this debug code with -XX:+UseNewCode to diagnose locations that
 475   // are missing a ThreadsListHandle or other protection mechanism:
 476   // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting p="
 477   //           INTPTR_FORMAT, p2i(current_thread), p2i(p));
 478 
 479   // Note: Since 'p' isn't protected by a TLH, the call to
 480   // p->is_handshake_safe_for() may crash, but we have debug bits so
 481   // we'll be able to figure out what protection mechanism is missing.
 482   assert(p->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
 483          " is not protected and not handshake safe.", p2i(p));
 484 
 485   // The target JavaThread is not protected so it is not safe to query:
 486   return false;
 487 }
 488 
 489 ThreadPriority Thread::get_priority(const Thread* const thread) {
 490   ThreadPriority priority;
 491   // Can return an error!
 492   (void)os::get_priority(thread, priority);
 493   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 494   return priority;
 495 }
 496 
 497 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 498   debug_only(check_for_dangling_thread_pointer(thread);)
 499   // Can return an error!
 500   (void)os::set_priority(thread, priority);
 501 }
 502 
 503 
 504 void Thread::start(Thread* thread) {
 505   // Start is different from resume in that its safety is guaranteed by context or
 506   // being called from a Java method synchronized on the Thread object.
 507   if (thread->is_Java_thread()) {
 508     // Initialize the thread state to RUNNABLE before starting this thread.
 509     // Can not set it after the thread started because we do not know the
 510     // exact thread state at that time. It could be in MONITOR_WAIT or
 511     // in SLEEPING or some other state.
 512     java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
 513                                         JavaThreadStatus::RUNNABLE);
 514   }
 515   os::start_thread(thread);
 516 }
 517 
 518 // GC Support
 519 bool Thread::claim_par_threads_do(uintx claim_token) {
 520   uintx token = _threads_do_token;
 521   if (token != claim_token) {
 522     uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
 523     if (res == token) {
 524       return true;
 525     }
 526     guarantee(res == claim_token, "invariant");
 527   }
 528   return false;
 529 }
 530 
 531 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
 532   if (active_handles() != NULL) {
 533     active_handles()->oops_do(f);
 534   }
 535   // Do oop for ThreadShadow
 536   f->do_oop((oop*)&_pending_exception);
 537   handle_area()->oops_do(f);
 538 }
 539 
 540 // If the caller is a NamedThread, then remember, in the current scope,
 541 // the given JavaThread in its _processed_thread field.
 542 class RememberProcessedThread: public StackObj {
 543   NamedThread* _cur_thr;
 544 public:
 545   RememberProcessedThread(Thread* thread) {
 546     Thread* self = Thread::current();
 547     if (self->is_Named_thread()) {
 548       _cur_thr = (NamedThread *)self;
 549       assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
 550       _cur_thr->set_processed_thread(thread);
 551     } else {
 552       _cur_thr = NULL;
 553     }
 554   }
 555 
 556   ~RememberProcessedThread() {
 557     if (_cur_thr) {
 558       assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
 559       _cur_thr->set_processed_thread(NULL);
 560     }
 561   }
 562 };
 563 
 564 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 565   // Record JavaThread to GC thread
 566   RememberProcessedThread rpt(this);
 567   oops_do_no_frames(f, cf);
 568   oops_do_frames(f, cf);
 569 }
 570 
 571 void Thread::metadata_handles_do(void f(Metadata*)) {
 572   // Only walk the Handles in Thread.
 573   if (metadata_handles() != NULL) {
 574     for (int i = 0; i< metadata_handles()->length(); i++) {
 575       f(metadata_handles()->at(i));
 576     }
 577   }
 578 }
 579 
 580 void Thread::print_on(outputStream* st, bool print_extended_info) const {
 581   // get_priority assumes osthread initialized
 582   if (osthread() != NULL) {
 583     int os_prio;
 584     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 585       st->print("os_prio=%d ", os_prio);
 586     }
 587 
 588     st->print("cpu=%.2fms ",
 589               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 590               );
 591     st->print("elapsed=%.2fs ",
 592               _statistical_info.getElapsedTime() / 1000.0
 593               );
 594     if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
 595       size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
 596       st->print("allocated=" SIZE_FORMAT "%s ",
 597                 byte_size_in_proper_unit(allocated_bytes),
 598                 proper_unit_for_byte_size(allocated_bytes)
 599                 );
 600       st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
 601     }
 602 
 603     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 604     osthread()->print_on(st);
 605   }
 606   ThreadsSMRSupport::print_info_on(this, st);
 607   st->print(" ");
 608   debug_only(if (WizardMode) print_owned_locks_on(st);)
 609 }
 610 
 611 void Thread::print() const { print_on(tty); }
 612 
 613 // Thread::print_on_error() is called by fatal error handler. Don't use
 614 // any lock or allocate memory.
 615 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 616   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 617 
 618   st->print("%s \"%s\"", type_name(), name());
 619 
 620   OSThread* os_thr = osthread();
 621   if (os_thr != NULL) {
 622     if (os_thr->get_state() != ZOMBIE) {
 623       st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 624                 p2i(stack_end()), p2i(stack_base()));
 625       st->print(" [id=%d]", osthread()->thread_id());
 626     } else {
 627       st->print(" terminated");
 628     }
 629   } else {
 630     st->print(" unknown state (no osThread)");
 631   }
 632   ThreadsSMRSupport::print_info_on(this, st);
 633 }
 634 
 635 void Thread::print_value_on(outputStream* st) const {
 636   if (is_Named_thread()) {
 637     st->print(" \"%s\" ", name());
 638   }
 639   st->print(INTPTR_FORMAT, p2i(this));   // print address
 640 }
 641 
 642 #ifdef ASSERT
 643 void Thread::print_owned_locks_on(outputStream* st) const {
 644   Mutex* cur = _owned_locks;
 645   if (cur == NULL) {
 646     st->print(" (no locks) ");
 647   } else {
 648     st->print_cr(" Locks owned:");
 649     while (cur) {
 650       cur->print_on(st);
 651       cur = cur->next();
 652     }
 653   }
 654 }
 655 #endif // ASSERT
 656 
 657 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 658 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 659 // used for compilation in the future. If that change is made, the need for these methods
 660 // should be revisited, and they should be removed if possible.
 661 
 662 bool Thread::is_lock_owned(address adr) const {
 663   return is_in_full_stack(adr);
 664 }
 665 
 666 bool Thread::set_as_starting_thread() {
 667   assert(_starting_thread == NULL, "already initialized: "
 668          "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
 669   // NOTE: this must be called inside the main thread.
 670   DEBUG_ONLY(_starting_thread = this;)
 671   return os::create_main_thread(JavaThread::cast(this));
 672 }
 673 
 674 static void initialize_class(Symbol* class_name, TRAPS) {
 675   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 676   InstanceKlass::cast(klass)->initialize(CHECK);
 677 }
 678 
 679 
 680 // Creates the initial ThreadGroup
 681 static Handle create_initial_thread_group(TRAPS) {
 682   Handle system_instance = JavaCalls::construct_new_instance(
 683                             vmClasses::ThreadGroup_klass(),
 684                             vmSymbols::void_method_signature(),
 685                             CHECK_NH);
 686   Universe::set_system_thread_group(system_instance());
 687 
 688   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 689   Handle main_instance = JavaCalls::construct_new_instance(
 690                             vmClasses::ThreadGroup_klass(),
 691                             vmSymbols::threadgroup_string_void_signature(),
 692                             system_instance,
 693                             string,
 694                             CHECK_NH);
 695   return main_instance;
 696 }
 697 
 698 // Creates the initial Thread, and sets it to running.
 699 static void create_initial_thread(Handle thread_group, JavaThread* thread,
 700                                  TRAPS) {
 701   InstanceKlass* ik = vmClasses::Thread_klass();
 702   assert(ik->is_initialized(), "must be");
 703   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 704 
 705   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 706   // constructor calls Thread.current(), which must be set here for the
 707   // initial thread.
 708   java_lang_Thread::set_thread(thread_oop(), thread);
 709   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 710   thread->set_threadObj(thread_oop());
 711 
 712   Handle string = java_lang_String::create_from_str("main", CHECK);
 713 
 714   JavaValue result(T_VOID);
 715   JavaCalls::call_special(&result, thread_oop,
 716                           ik,
 717                           vmSymbols::object_initializer_name(),
 718                           vmSymbols::threadgroup_string_void_signature(),
 719                           thread_group,
 720                           string,
 721                           CHECK);
 722 
 723   // Set thread status to running since main thread has
 724   // been started and running.
 725   java_lang_Thread::set_thread_status(thread_oop(),
 726                                       JavaThreadStatus::RUNNABLE);
 727 }
 728 
 729 // Extract version and vendor specific information from
 730 // java.lang.VersionProps fields.
 731 // Returned char* is allocated in the thread's resource area
 732 // so must be copied for permanency.
 733 static const char* get_java_version_info(InstanceKlass* ik,
 734                                          Symbol* field_name) {
 735   fieldDescriptor fd;
 736   bool found = ik != NULL &&
 737                ik->find_local_field(field_name,
 738                                     vmSymbols::string_signature(), &fd);
 739   if (found) {
 740     oop name_oop = ik->java_mirror()->obj_field(fd.offset());
 741     if (name_oop == NULL) {
 742       return NULL;
 743     }
 744     const char* name = java_lang_String::as_utf8_string(name_oop);
 745     return name;
 746   } else {
 747     return NULL;
 748   }
 749 }
 750 
 751 // General purpose hook into Java code, run once when the VM is initialized.
 752 // The Java library method itself may be changed independently from the VM.
 753 static void call_postVMInitHook(TRAPS) {
 754   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
 755   if (klass != NULL) {
 756     JavaValue result(T_VOID);
 757     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
 758                            vmSymbols::void_method_signature(),
 759                            CHECK);
 760   }
 761 }
 762 
 763 // Initialized by VMThread at vm_global_init
 764 static OopStorage* _thread_oop_storage = NULL;
 765 
 766 oop  JavaThread::threadObj() const    {
 767   return _threadObj.resolve();
 768 }
 769 
 770 void JavaThread::set_threadObj(oop p) {
 771   assert(_thread_oop_storage != NULL, "not yet initialized");
 772   _threadObj = OopHandle(_thread_oop_storage, p);
 773 }
 774 
 775 OopStorage* JavaThread::thread_oop_storage() {
 776   assert(_thread_oop_storage != NULL, "not yet initialized");
 777   return _thread_oop_storage;
 778 }
 779 
 780 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 781                                     bool daemon, TRAPS) {
 782   assert(thread_group.not_null(), "thread group should be specified");
 783   assert(threadObj() == NULL, "should only create Java thread object once");
 784 
 785   InstanceKlass* ik = vmClasses::Thread_klass();
 786   assert(ik->is_initialized(), "must be");
 787   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 788 
 789   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 790   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 791   // constructor calls Thread.current(), which must be set here.
 792   java_lang_Thread::set_thread(thread_oop(), this);
 793   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 794   set_threadObj(thread_oop());
 795 
 796   JavaValue result(T_VOID);
 797   if (thread_name != NULL) {
 798     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 799     // Thread gets assigned specified name and null target
 800     JavaCalls::call_special(&result,
 801                             thread_oop,
 802                             ik,
 803                             vmSymbols::object_initializer_name(),
 804                             vmSymbols::threadgroup_string_void_signature(),
 805                             thread_group,
 806                             name,
 807                             THREAD);
 808   } else {
 809     // Thread gets assigned name "Thread-nnn" and null target
 810     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 811     JavaCalls::call_special(&result,
 812                             thread_oop,
 813                             ik,
 814                             vmSymbols::object_initializer_name(),
 815                             vmSymbols::threadgroup_runnable_void_signature(),
 816                             thread_group,
 817                             Handle(),
 818                             THREAD);
 819   }
 820 
 821 
 822   if (daemon) {
 823     java_lang_Thread::set_daemon(thread_oop());
 824   }
 825 
 826   if (HAS_PENDING_EXCEPTION) {
 827     return;
 828   }
 829 
 830   Klass* group = vmClasses::ThreadGroup_klass();
 831   Handle threadObj(THREAD, this->threadObj());
 832 
 833   JavaCalls::call_special(&result,
 834                           thread_group,
 835                           group,
 836                           vmSymbols::add_method_name(),
 837                           vmSymbols::thread_void_signature(),
 838                           threadObj,          // Arg 1
 839                           THREAD);
 840 }
 841 
 842 // ======= JavaThread ========
 843 
 844 #if INCLUDE_JVMCI
 845 
 846 jlong* JavaThread::_jvmci_old_thread_counters;
 847 
 848 bool jvmci_counters_include(JavaThread* thread) {
 849   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 850 }
 851 
 852 void JavaThread::collect_counters(jlong* array, int length) {
 853   assert(length == JVMCICounterSize, "wrong value");
 854   for (int i = 0; i < length; i++) {
 855     array[i] = _jvmci_old_thread_counters[i];
 856   }
 857   for (JavaThread* tp : ThreadsListHandle()) {
 858     if (jvmci_counters_include(tp)) {
 859       for (int i = 0; i < length; i++) {
 860         array[i] += tp->_jvmci_counters[i];
 861       }
 862     }
 863   }
 864 }
 865 
 866 // Attempt to enlarge the array for per thread counters.
 867 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 868   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 869   if (new_counters == NULL) {
 870     return NULL;
 871   }
 872   if (old_counters == NULL) {
 873     old_counters = new_counters;
 874     memset(old_counters, 0, sizeof(jlong) * new_size);
 875   } else {
 876     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 877       new_counters[i] = old_counters[i];
 878     }
 879     if (new_size > current_size) {
 880       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 881     }
 882     FREE_C_HEAP_ARRAY(jlong, old_counters);
 883   }
 884   return new_counters;
 885 }
 886 
 887 // Attempt to enlarge the array for per thread counters.
 888 bool JavaThread::resize_counters(int current_size, int new_size) {
 889   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 890   if (new_counters == NULL) {
 891     return false;
 892   } else {
 893     _jvmci_counters = new_counters;
 894     return true;
 895   }
 896 }
 897 
 898 class VM_JVMCIResizeCounters : public VM_Operation {
 899  private:
 900   int _new_size;
 901   bool _failed;
 902 
 903  public:
 904   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 905   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 906   bool allow_nested_vm_operations() const        { return true; }
 907   void doit() {
 908     // Resize the old thread counters array
 909     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 910     if (new_counters == NULL) {
 911       _failed = true;
 912       return;
 913     } else {
 914       JavaThread::_jvmci_old_thread_counters = new_counters;
 915     }
 916 
 917     // Now resize each threads array
 918     for (JavaThread* tp : ThreadsListHandle()) {
 919       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 920         _failed = true;
 921         break;
 922       }
 923     }
 924     if (!_failed) {
 925       JVMCICounterSize = _new_size;
 926     }
 927   }
 928 
 929   bool failed() { return _failed; }
 930 };
 931 
 932 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 933   VM_JVMCIResizeCounters op(new_size);
 934   VMThread::execute(&op);
 935   return !op.failed();
 936 }
 937 
 938 #endif // INCLUDE_JVMCI
 939 
 940 #ifdef ASSERT
 941 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 942 void JavaThread::check_possible_safepoint() {
 943   if (_no_safepoint_count > 0) {
 944     print_owned_locks();
 945     assert(false, "Possible safepoint reached by thread that does not allow it");
 946   }
 947 #ifdef CHECK_UNHANDLED_OOPS
 948   // Clear unhandled oops in JavaThreads so we get a crash right away.
 949   clear_unhandled_oops();
 950 #endif // CHECK_UNHANDLED_OOPS
 951 
 952   // Macos/aarch64 should be in the right state for safepoint (e.g.
 953   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 954   // happens in practice, making such issues hard to find and reproduce.
 955 #if defined(__APPLE__) && defined(AARCH64)
 956   if (AssertWXAtThreadSync) {
 957     assert_wx_state(WXWrite);
 958   }
 959 #endif
 960 }
 961 
 962 void JavaThread::check_for_valid_safepoint_state() {
 963   // Check NoSafepointVerifier, which is implied by locks taken that can be
 964   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 965   // are held.
 966   check_possible_safepoint();
 967 
 968   if (thread_state() != _thread_in_vm) {
 969     fatal("LEAF method calling lock?");
 970   }
 971 
 972   if (GCALotAtAllSafepoints) {
 973     // We could enter a safepoint here and thus have a gc
 974     InterfaceSupport::check_gc_alot();
 975   }
 976 }
 977 #endif // ASSERT
 978 
 979 // A JavaThread is a normal Java thread
 980 
 981 JavaThread::JavaThread() :
 982   // Initialize fields
 983 
 984   _on_thread_list(false),
 985   DEBUG_ONLY(_java_call_counter(0) COMMA)
 986   _entry_point(nullptr),
 987   _deopt_mark(nullptr),
 988   _deopt_nmethod(nullptr),
 989   _vframe_array_head(nullptr),
 990   _vframe_array_last(nullptr),
 991   _jvmti_deferred_updates(nullptr),
 992   _callee_target(nullptr),
 993   _vm_result(nullptr),
 994   _vm_result_2(nullptr),
 995 
 996   _current_pending_monitor(NULL),
 997   _current_pending_monitor_is_from_java(true),
 998   _current_waiting_monitor(NULL),
 999   _Stalled(0),
1000 
1001   _monitor_chunks(nullptr),
1002 
1003   _suspend_flags(0),
1004   _pending_async_exception(nullptr),
1005 #ifdef ASSERT
1006   _is_unsafe_access_error(false),
1007 #endif
1008 
1009   _thread_state(_thread_new),
1010   _saved_exception_pc(nullptr),
1011 #ifdef ASSERT
1012   _no_safepoint_count(0),
1013   _visited_for_critical_count(false),
1014 #endif
1015 
1016   _terminated(_not_terminated),
1017   _in_deopt_handler(0),
1018   _doing_unsafe_access(false),
1019   _do_not_unlock_if_synchronized(false),
1020   _jni_attach_state(_not_attaching_via_jni),
1021 #if INCLUDE_JVMCI
1022   _pending_deoptimization(-1),
1023   _pending_monitorenter(false),
1024   _pending_transfer_to_interpreter(false),
1025   _in_retryable_allocation(false),
1026   _pending_failed_speculation(0),
1027   _jvmci{nullptr},
1028   _jvmci_counters(nullptr),
1029   _jvmci_reserved0(0),
1030   _jvmci_reserved1(0),
1031   _jvmci_reserved_oop0(nullptr),
1032 #endif // INCLUDE_JVMCI
1033 
1034   _exception_oop(oop()),
1035   _exception_pc(0),
1036   _exception_handler_pc(0),
1037   _is_method_handle_return(0),
1038 
1039   _jni_active_critical(0),
1040   _pending_jni_exception_check_fn(nullptr),
1041   _depth_first_number(0),
1042 
1043   // JVMTI PopFrame support
1044   _popframe_condition(popframe_inactive),
1045   _frames_to_pop_failed_realloc(0),
1046 
1047   _handshake(this),
1048 
1049   _popframe_preserved_args(nullptr),
1050   _popframe_preserved_args_size(0),
1051 
1052   _jvmti_thread_state(nullptr),
1053   _interp_only_mode(0),
1054   _should_post_on_exceptions_flag(JNI_FALSE),
1055   _thread_stat(new ThreadStatistics()),
1056 
1057   _parker(),
1058 
1059   _class_to_be_initialized(nullptr),
1060 
1061   _SleepEvent(ParkEvent::Allocate(this))
1062 {
1063   set_jni_functions(jni_functions());
1064 
1065 #if INCLUDE_JVMCI
1066   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
1067   if (JVMCICounterSize > 0) {
1068     resize_counters(0, (int) JVMCICounterSize);
1069   }
1070 #endif // INCLUDE_JVMCI
1071 
1072   // Setup safepoint state info for this thread
1073   ThreadSafepointState::create(this);
1074 
1075   SafepointMechanism::initialize_header(this);
1076 
1077   set_requires_cross_modify_fence(false);
1078 
1079   pd_initialize();
1080   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1081 }
1082 
1083 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
1084   if (is_attaching_via_jni) {
1085     _jni_attach_state = _attaching_via_jni;
1086   }
1087 }
1088 
1089 
1090 // interrupt support
1091 
1092 void JavaThread::interrupt() {
1093   // All callers should have 'this' thread protected by a
1094   // ThreadsListHandle so that it cannot terminate and deallocate
1095   // itself.
1096   debug_only(check_for_dangling_thread_pointer(this);)
1097 
1098   // For Windows _interrupt_event
1099   osthread()->set_interrupted(true);
1100 
1101   // For Thread.sleep
1102   _SleepEvent->unpark();
1103 
1104   // For JSR166 LockSupport.park
1105   parker()->unpark();
1106 
1107   // For ObjectMonitor and JvmtiRawMonitor
1108   _ParkEvent->unpark();
1109 }
1110 
1111 
1112 bool JavaThread::is_interrupted(bool clear_interrupted) {
1113   debug_only(check_for_dangling_thread_pointer(this);)
1114 
1115   if (_threadObj.peek() == NULL) {
1116     // If there is no j.l.Thread then it is impossible to have
1117     // been interrupted. We can find NULL during VM initialization
1118     // or when a JNI thread is still in the process of attaching.
1119     // In such cases this must be the current thread.
1120     assert(this == Thread::current(), "invariant");
1121     return false;
1122   }
1123 
1124   bool interrupted = java_lang_Thread::interrupted(threadObj());
1125 
1126   // NOTE that since there is no "lock" around the interrupt and
1127   // is_interrupted operations, there is the possibility that the
1128   // interrupted flag will be "false" but that the
1129   // low-level events will be in the signaled state. This is
1130   // intentional. The effect of this is that Object.wait() and
1131   // LockSupport.park() will appear to have a spurious wakeup, which
1132   // is allowed and not harmful, and the possibility is so rare that
1133   // it is not worth the added complexity to add yet another lock.
1134   // For the sleep event an explicit reset is performed on entry
1135   // to JavaThread::sleep, so there is no early return. It has also been
1136   // recommended not to put the interrupted flag into the "event"
1137   // structure because it hides the issue.
1138   // Also, because there is no lock, we must only clear the interrupt
1139   // state if we are going to report that we were interrupted; otherwise
1140   // an interrupt that happens just after we read the field would be lost.
1141   if (interrupted && clear_interrupted) {
1142     assert(this == Thread::current(), "only the current thread can clear");
1143     java_lang_Thread::set_interrupted(threadObj(), false);
1144     osthread()->set_interrupted(false);
1145   }
1146 
1147   return interrupted;
1148 }
1149 
1150 void JavaThread::block_if_vm_exited() {
1151   if (_terminated == _vm_exited) {
1152     // _vm_exited is set at safepoint, and Threads_lock is never released
1153     // we will block here forever.
1154     // Here we can be doing a jump from a safe state to an unsafe state without
1155     // proper transition, but it happens after the final safepoint has begun.
1156     set_thread_state(_thread_in_vm);
1157     Threads_lock->lock();
1158     ShouldNotReachHere();
1159   }
1160 }
1161 
1162 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
1163   _jni_attach_state = _not_attaching_via_jni;
1164   set_entry_point(entry_point);
1165   // Create the native thread itself.
1166   // %note runtime_23
1167   os::ThreadType thr_type = os::java_thread;
1168   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
1169                                                             os::java_thread;
1170   os::create_thread(this, thr_type, stack_sz);
1171   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1172   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1173   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1174   // the exception consists of creating the exception object & initializing it, initialization
1175   // will leave the VM via a JavaCall and then all locks must be unlocked).
1176   //
1177   // The thread is still suspended when we reach here. Thread must be explicit started
1178   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1179   // by calling Threads:add. The reason why this is not done here, is because the thread
1180   // object must be fully initialized (take a look at JVM_Start)
1181 }
1182 
1183 JavaThread::~JavaThread() {
1184 
1185   // Ask ServiceThread to release the threadObj OopHandle
1186   ServiceThread::add_oop_handle_release(_threadObj);
1187 
1188   // Return the sleep event to the free list
1189   ParkEvent::Release(_SleepEvent);
1190   _SleepEvent = NULL;
1191 
1192   // Free any remaining  previous UnrollBlock
1193   vframeArray* old_array = vframe_array_last();
1194 
1195   if (old_array != NULL) {
1196     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1197     old_array->set_unroll_block(NULL);
1198     delete old_info;
1199     delete old_array;
1200   }
1201 
1202   JvmtiDeferredUpdates* updates = deferred_updates();
1203   if (updates != NULL) {
1204     // This can only happen if thread is destroyed before deoptimization occurs.
1205     assert(updates->count() > 0, "Updates holder not deleted");
1206     // free deferred updates.
1207     delete updates;
1208     set_deferred_updates(NULL);
1209   }
1210 
1211   // All Java related clean up happens in exit
1212   ThreadSafepointState::destroy(this);
1213   if (_thread_stat != NULL) delete _thread_stat;
1214 
1215 #if INCLUDE_JVMCI
1216   if (JVMCICounterSize > 0) {
1217     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1218   }
1219 #endif // INCLUDE_JVMCI
1220 }
1221 
1222 
1223 // First JavaThread specific code executed by a new Java thread.
1224 void JavaThread::pre_run() {
1225   // empty - see comments in run()
1226 }
1227 
1228 // The main routine called by a new Java thread. This isn't overridden
1229 // by subclasses, instead different subclasses define a different "entry_point"
1230 // which defines the actual logic for that kind of thread.
1231 void JavaThread::run() {
1232   // initialize thread-local alloc buffer related fields
1233   initialize_tlab();
1234 
1235   _stack_overflow_state.create_stack_guard_pages();
1236 
1237   cache_global_variables();
1238 
1239   // Thread is now sufficiently initialized to be handled by the safepoint code as being
1240   // in the VM. Change thread state from _thread_new to _thread_in_vm
1241   assert(this->thread_state() == _thread_new, "wrong thread state");
1242   set_thread_state(_thread_in_vm);
1243 
1244   // Before a thread is on the threads list it is always safe, so after leaving the
1245   // _thread_new we should emit a instruction barrier. The distance to modified code
1246   // from here is probably far enough, but this is consistent and safe.
1247   OrderAccess::cross_modify_fence();
1248 
1249   assert(JavaThread::current() == this, "sanity check");
1250   assert(!Thread::current()->owns_locks(), "sanity check");
1251 
1252   DTRACE_THREAD_PROBE(start, this);
1253 
1254   // This operation might block. We call that after all safepoint checks for a new thread has
1255   // been completed.
1256   set_active_handles(JNIHandleBlock::allocate_block());
1257 
1258   if (JvmtiExport::should_post_thread_life()) {
1259     JvmtiExport::post_thread_start(this);
1260 
1261   }
1262 
1263   // We call another function to do the rest so we are sure that the stack addresses used
1264   // from there will be lower than the stack base just computed.
1265   thread_main_inner();
1266 }
1267 
1268 void JavaThread::thread_main_inner() {
1269   assert(JavaThread::current() == this, "sanity check");
1270   assert(_threadObj.peek() != NULL, "just checking");
1271 
1272   // Execute thread entry point unless this thread has a pending exception
1273   // or has been stopped before starting.
1274   // Note: Due to JVM_StopThread we can have pending exceptions already!
1275   if (!this->has_pending_exception() &&
1276       !java_lang_Thread::is_stillborn(this->threadObj())) {
1277     {
1278       ResourceMark rm(this);
1279       this->set_native_thread_name(this->name());
1280     }
1281     HandleMark hm(this);
1282     this->entry_point()(this, this);
1283   }
1284 
1285   DTRACE_THREAD_PROBE(stop, this);
1286 
1287   // Cleanup is handled in post_run()
1288 }
1289 
1290 // Shared teardown for all JavaThreads
1291 void JavaThread::post_run() {
1292   this->exit(false);
1293   this->unregister_thread_stack_with_NMT();
1294   // Defer deletion to here to ensure 'this' is still referenceable in call_run
1295   // for any shared tear-down.
1296   this->smr_delete();
1297 }
1298 
1299 static void ensure_join(JavaThread* thread) {
1300   // We do not need to grab the Threads_lock, since we are operating on ourself.
1301   Handle threadObj(thread, thread->threadObj());
1302   assert(threadObj.not_null(), "java thread object must exist");
1303   ObjectLocker lock(threadObj, thread);
1304   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1305   thread->clear_pending_exception();
1306   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1307   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
1308   // Clear the native thread instance - this makes isAlive return false and allows the join()
1309   // to complete once we've done the notify_all below
1310   java_lang_Thread::set_thread(threadObj(), NULL);
1311   lock.notify_all(thread);
1312   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1313   thread->clear_pending_exception();
1314 }
1315 
1316 static bool is_daemon(oop threadObj) {
1317   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
1318 }
1319 
1320 // For any new cleanup additions, please check to see if they need to be applied to
1321 // cleanup_failed_attach_current_thread as well.
1322 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1323   assert(this == JavaThread::current(), "thread consistency check");
1324 
1325   elapsedTimer _timer_exit_phase1;
1326   elapsedTimer _timer_exit_phase2;
1327   elapsedTimer _timer_exit_phase3;
1328   elapsedTimer _timer_exit_phase4;
1329 
1330   if (log_is_enabled(Debug, os, thread, timer)) {
1331     _timer_exit_phase1.start();
1332   }
1333 
1334   HandleMark hm(this);
1335   Handle uncaught_exception(this, this->pending_exception());
1336   this->clear_pending_exception();
1337   Handle threadObj(this, this->threadObj());
1338   assert(threadObj.not_null(), "Java thread object should be created");
1339 
1340   if (!destroy_vm) {
1341     if (uncaught_exception.not_null()) {
1342       EXCEPTION_MARK;
1343       // Call method Thread.dispatchUncaughtException().
1344       Klass* thread_klass = vmClasses::Thread_klass();
1345       JavaValue result(T_VOID);
1346       JavaCalls::call_virtual(&result,
1347                               threadObj, thread_klass,
1348                               vmSymbols::dispatchUncaughtException_name(),
1349                               vmSymbols::throwable_void_signature(),
1350                               uncaught_exception,
1351                               THREAD);
1352       if (HAS_PENDING_EXCEPTION) {
1353         ResourceMark rm(this);
1354         jio_fprintf(defaultStream::error_stream(),
1355                     "\nException: %s thrown from the UncaughtExceptionHandler"
1356                     " in thread \"%s\"\n",
1357                     pending_exception()->klass()->external_name(),
1358                     name());
1359         CLEAR_PENDING_EXCEPTION;
1360       }
1361     }
1362 
1363     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1364     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1365     // is deprecated anyhow.
1366     if (!is_Compiler_thread()) {
1367       int count = 3;
1368       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1369         EXCEPTION_MARK;
1370         JavaValue result(T_VOID);
1371         Klass* thread_klass = vmClasses::Thread_klass();
1372         JavaCalls::call_virtual(&result,
1373                                 threadObj, thread_klass,
1374                                 vmSymbols::exit_method_name(),
1375                                 vmSymbols::void_method_signature(),
1376                                 THREAD);
1377         CLEAR_PENDING_EXCEPTION;
1378       }
1379     }
1380     // notify JVMTI
1381     if (JvmtiExport::should_post_thread_life()) {
1382       JvmtiExport::post_thread_end(this);
1383     }
1384 
1385     // The careful dance between thread suspension and exit is handled here.
1386     // Since we are in thread_in_vm state and suspension is done with handshakes,
1387     // we can just put in the exiting state and it will be correctly handled.
1388     set_terminated(_thread_exiting);
1389 
1390     ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
1391   } else {
1392     assert(!is_terminated() && !is_exiting(), "must not be exiting");
1393     // before_exit() has already posted JVMTI THREAD_END events
1394   }
1395 
1396   if (log_is_enabled(Debug, os, thread, timer)) {
1397     _timer_exit_phase1.stop();
1398     _timer_exit_phase2.start();
1399   }
1400 
1401   // Capture daemon status before the thread is marked as terminated.
1402   bool daemon = is_daemon(threadObj());
1403 
1404   // Notify waiters on thread object. This has to be done after exit() is called
1405   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1406   // group should have the destroyed bit set before waiters are notified).
1407   ensure_join(this);
1408   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1409 
1410   if (log_is_enabled(Debug, os, thread, timer)) {
1411     _timer_exit_phase2.stop();
1412     _timer_exit_phase3.start();
1413   }
1414   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1415   // held by this thread must be released. The spec does not distinguish
1416   // between JNI-acquired and regular Java monitors. We can only see
1417   // regular Java monitors here if monitor enter-exit matching is broken.
1418   //
1419   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1420   // ObjectSynchronizer::release_monitors_owned_by_thread().
1421   if (exit_type == jni_detach) {
1422     // Sanity check even though JNI DetachCurrentThread() would have
1423     // returned JNI_ERR if there was a Java frame. JavaThread exit
1424     // should be done executing Java code by the time we get here.
1425     assert(!this->has_last_Java_frame(),
1426            "should not have a Java frame when detaching or exiting");
1427     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1428     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1429   }
1430 
1431   // These things needs to be done while we are still a Java Thread. Make sure that thread
1432   // is in a consistent state, in case GC happens
1433   JFR_ONLY(Jfr::on_thread_exit(this);)
1434 
1435   if (active_handles() != NULL) {
1436     JNIHandleBlock* block = active_handles();
1437     set_active_handles(NULL);
1438     JNIHandleBlock::release_block(block);
1439   }
1440 
1441   if (free_handle_block() != NULL) {
1442     JNIHandleBlock* block = free_handle_block();
1443     set_free_handle_block(NULL);
1444     JNIHandleBlock::release_block(block);
1445   }
1446 
1447   // These have to be removed while this is still a valid thread.
1448   _stack_overflow_state.remove_stack_guard_pages();
1449 
1450   if (UseTLAB) {
1451     tlab().retire();
1452   }
1453 
1454   if (JvmtiEnv::environments_might_exist()) {
1455     JvmtiExport::cleanup_thread(this);
1456   }
1457 
1458   // We need to cache the thread name for logging purposes below as once
1459   // we have called on_thread_detach this thread must not access any oops.
1460   char* thread_name = NULL;
1461   if (log_is_enabled(Debug, os, thread, timer)) {
1462     ResourceMark rm(this);
1463     thread_name = os::strdup(name());
1464   }
1465 
1466   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1467     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1468     os::current_thread_id());
1469 
1470   if (log_is_enabled(Debug, os, thread, timer)) {
1471     _timer_exit_phase3.stop();
1472     _timer_exit_phase4.start();
1473   }
1474 
1475 #if INCLUDE_JVMCI
1476   if (JVMCICounterSize > 0) {
1477     if (jvmci_counters_include(this)) {
1478       for (int i = 0; i < JVMCICounterSize; i++) {
1479         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1480       }
1481     }
1482   }
1483 #endif // INCLUDE_JVMCI
1484 
1485   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1486   Threads::remove(this, daemon);
1487 
1488   if (log_is_enabled(Debug, os, thread, timer)) {
1489     _timer_exit_phase4.stop();
1490     log_debug(os, thread, timer)("name='%s'"
1491                                  ", exit-phase1=" JLONG_FORMAT
1492                                  ", exit-phase2=" JLONG_FORMAT
1493                                  ", exit-phase3=" JLONG_FORMAT
1494                                  ", exit-phase4=" JLONG_FORMAT,
1495                                  thread_name,
1496                                  _timer_exit_phase1.milliseconds(),
1497                                  _timer_exit_phase2.milliseconds(),
1498                                  _timer_exit_phase3.milliseconds(),
1499                                  _timer_exit_phase4.milliseconds());
1500     os::free(thread_name);
1501   }
1502 }
1503 
1504 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1505   if (active_handles() != NULL) {
1506     JNIHandleBlock* block = active_handles();
1507     set_active_handles(NULL);
1508     JNIHandleBlock::release_block(block);
1509   }
1510 
1511   if (free_handle_block() != NULL) {
1512     JNIHandleBlock* block = free_handle_block();
1513     set_free_handle_block(NULL);
1514     JNIHandleBlock::release_block(block);
1515   }
1516 
1517   // These have to be removed while this is still a valid thread.
1518   _stack_overflow_state.remove_stack_guard_pages();
1519 
1520   if (UseTLAB) {
1521     tlab().retire();
1522   }
1523 
1524   Threads::remove(this, is_daemon);
1525   this->smr_delete();
1526 }
1527 
1528 JavaThread* JavaThread::active() {
1529   Thread* thread = Thread::current();
1530   if (thread->is_Java_thread()) {
1531     return JavaThread::cast(thread);
1532   } else {
1533     assert(thread->is_VM_thread(), "this must be a vm thread");
1534     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1535     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
1536     return ret;
1537   }
1538 }
1539 
1540 bool JavaThread::is_lock_owned(address adr) const {
1541   if (Thread::is_lock_owned(adr)) return true;
1542 
1543   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1544     if (chunk->contains(adr)) return true;
1545   }
1546 
1547   return false;
1548 }
1549 
1550 oop JavaThread::exception_oop() const {
1551   return Atomic::load(&_exception_oop);
1552 }
1553 
1554 void JavaThread::set_exception_oop(oop o) {
1555   Atomic::store(&_exception_oop, o);
1556 }
1557 
1558 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1559   chunk->set_next(monitor_chunks());
1560   set_monitor_chunks(chunk);
1561 }
1562 
1563 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1564   guarantee(monitor_chunks() != NULL, "must be non empty");
1565   if (monitor_chunks() == chunk) {
1566     set_monitor_chunks(chunk->next());
1567   } else {
1568     MonitorChunk* prev = monitor_chunks();
1569     while (prev->next() != chunk) prev = prev->next();
1570     prev->set_next(chunk->next());
1571   }
1572 }
1573 
1574 
1575 // Asynchronous exceptions support
1576 //
1577 void JavaThread::check_and_handle_async_exceptions() {
1578   if (has_last_Java_frame() && has_async_exception_condition()) {
1579     // If we are at a polling page safepoint (not a poll return)
1580     // then we must defer async exception because live registers
1581     // will be clobbered by the exception path. Poll return is
1582     // ok because the call we a returning from already collides
1583     // with exception handling registers and so there is no issue.
1584     // (The exception handling path kills call result registers but
1585     //  this is ok since the exception kills the result anyway).
1586 
1587     if (is_at_poll_safepoint()) {
1588       // if the code we are returning to has deoptimized we must defer
1589       // the exception otherwise live registers get clobbered on the
1590       // exception path before deoptimization is able to retrieve them.
1591       //
1592       RegisterMap map(this, false);
1593       frame caller_fr = last_frame().sender(&map);
1594       assert(caller_fr.is_compiled_frame(), "what?");
1595       if (caller_fr.is_deoptimized_frame()) {
1596         log_info(exceptions)("deferred async exception at compiled safepoint");
1597         return;
1598       }
1599     }
1600   }
1601 
1602   if (!clear_async_exception_condition()) {
1603     return;
1604   }
1605 
1606   if (_pending_async_exception != NULL) {
1607     // Only overwrite an already pending exception if it is not a threadDeath.
1608     if (!has_pending_exception() || !pending_exception()->is_a(vmClasses::ThreadDeath_klass())) {
1609 
1610       // We cannot call Exceptions::_throw(...) here because we cannot block
1611       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1612 
1613       LogTarget(Info, exceptions) lt;
1614       if (lt.is_enabled()) {
1615         ResourceMark rm;
1616         LogStream ls(lt);
1617         ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1618           if (has_last_Java_frame()) {
1619             frame f = last_frame();
1620            ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1621           }
1622         ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
1623       }
1624     }
1625     // Always null out the _pending_async_exception oop here since the async condition was
1626     // already cleared above and thus considered handled.
1627     _pending_async_exception = NULL;
1628   } else {
1629     assert(_is_unsafe_access_error, "must be");
1630     DEBUG_ONLY(_is_unsafe_access_error = false);
1631 
1632     // We may be at method entry which requires we save the do-not-unlock flag.
1633     UnlockFlagSaver fs(this);
1634     switch (thread_state()) {
1635     case _thread_in_vm: {
1636       JavaThread* THREAD = this;
1637       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation");
1638       // We might have blocked in a ThreadBlockInVM wrapper in the call above so make sure we process pending
1639       // suspend requests and object reallocation operations if any since we might be going to Java after this.
1640       SafepointMechanism::process_if_requested_with_exit_check(this, true /* check asyncs */);
1641       return;
1642     }
1643     case _thread_in_Java: {
1644       ThreadInVMfromJava tiv(this);
1645       JavaThread* THREAD = this;
1646       Exceptions::throw_unsafe_access_internal_error(THREAD, __FILE__, __LINE__, "a fault occurred in an unsafe memory access operation in compiled Java code");
1647       return;
1648     }
1649     default:
1650       ShouldNotReachHere();
1651     }
1652   }
1653 }
1654 
1655 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1656 
1657   if (is_obj_deopt_suspend()) {
1658     frame_anchor()->make_walkable(this);
1659     wait_for_object_deoptimization();
1660   }
1661 
1662   // We might be here for reasons in addition to the self-suspend request
1663   // so check for other async requests.
1664   if (check_asyncs) {
1665     check_and_handle_async_exceptions();
1666   }
1667 
1668   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1669 }
1670 
1671 class InstallAsyncExceptionClosure : public HandshakeClosure {
1672   Handle _throwable; // The Throwable thrown at the target Thread
1673 public:
1674   InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {}
1675 
1676   void do_thread(Thread* thr) {
1677     JavaThread* target = JavaThread::cast(thr);
1678     // Note that this now allows multiple ThreadDeath exceptions to be
1679     // thrown at a thread.
1680     // The target thread has run and has not exited yet.
1681     target->send_thread_stop(_throwable());
1682   }
1683 };
1684 
1685 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1686   Handle throwable(Thread::current(), java_throwable);
1687   InstallAsyncExceptionClosure vm_stop(throwable);
1688   Handshake::execute(&vm_stop, target);
1689 }
1690 
1691 void JavaThread::send_thread_stop(oop java_throwable)  {
1692   ResourceMark rm;
1693   assert(is_handshake_safe_for(Thread::current()),
1694          "should be self or handshakee");
1695 
1696   // Do not throw asynchronous exceptions against the compiler thread
1697   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1698   if (!can_call_java()) return;
1699 
1700   {
1701     // Actually throw the Throwable against the target Thread - however
1702     // only if there is no thread death exception installed already.
1703     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(vmClasses::ThreadDeath_klass())) {
1704       // If the topmost frame is a runtime stub, then we are calling into
1705       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1706       // must deoptimize the caller before continuing, as the compiled  exception handler table
1707       // may not be valid
1708       if (has_last_Java_frame()) {
1709         frame f = last_frame();
1710         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1711           RegisterMap reg_map(this, false);
1712           frame compiled_frame = f.sender(&reg_map);
1713           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1714             Deoptimization::deoptimize(this, compiled_frame);
1715           }
1716         }
1717       }
1718 
1719       // Set async. pending exception in thread.
1720       set_pending_async_exception(java_throwable);
1721 
1722       if (log_is_enabled(Info, exceptions)) {
1723          ResourceMark rm;
1724         log_info(exceptions)("Pending Async. exception installed of type: %s",
1725                              InstanceKlass::cast(_pending_async_exception->klass())->external_name());
1726       }
1727       // for AbortVMOnException flag
1728       Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
1729     }
1730   }
1731 
1732 
1733   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1734   java_lang_Thread::set_interrupted(threadObj(), true);
1735   this->interrupt();
1736 }
1737 
1738 
1739 // External suspension mechanism.
1740 //
1741 // Guarantees on return (for a valid target thread):
1742 //   - Target thread will not execute any new bytecode.
1743 //   - Target thread will not enter any new monitors.
1744 //
1745 bool JavaThread::java_suspend() {
1746   ThreadsListHandle tlh;
1747   if (!tlh.includes(this)) {
1748     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, no suspension", p2i(this));
1749     return false;
1750   }
1751   return this->handshake_state()->suspend();
1752 }
1753 
1754 bool JavaThread::java_resume() {
1755   ThreadsListHandle tlh;
1756   if (!tlh.includes(this)) {
1757     log_trace(thread, suspend)("JavaThread:" INTPTR_FORMAT " not on ThreadsList, nothing to resume", p2i(this));
1758     return false;
1759   }
1760   return this->handshake_state()->resume();
1761 }
1762 
1763 // Wait for another thread to perform object reallocation and relocking on behalf of
1764 // this thread.
1765 // Raw thread state transition to _thread_blocked and back again to the original
1766 // state before returning are performed. The current thread is required to
1767 // change to _thread_blocked in order to be seen to be safepoint/handshake safe
1768 // whilst suspended and only after becoming handshake safe, the other thread can
1769 // complete the handshake used to synchronize with this thread and then perform
1770 // the reallocation and relocking. We cannot use the thread state transition
1771 // helpers because we arrive here in various states and also because the helpers
1772 // indirectly call this method.  After leaving _thread_blocked we have to check
1773 // for safepoint/handshake, except if _thread_in_native. The thread is safe
1774 // without blocking then. Allowed states are enumerated in
1775 // SafepointSynchronize::block(). See also EscapeBarrier::sync_and_suspend_*()
1776 
1777 void JavaThread::wait_for_object_deoptimization() {
1778   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1779   assert(this == Thread::current(), "invariant");
1780   JavaThreadState state = thread_state();
1781 
1782   bool spin_wait = os::is_MP();
1783   do {
1784     set_thread_state(_thread_blocked);
1785     // Wait for object deoptimization if requested.
1786     if (spin_wait) {
1787       // A single deoptimization is typically very short. Microbenchmarks
1788       // showed 5% better performance when spinning.
1789       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1790       SpinYield spin(spin_limit);
1791       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1792         spin.wait();
1793       }
1794       // Spin just once
1795       spin_wait = false;
1796     } else {
1797       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1798       if (is_obj_deopt_suspend()) {
1799         ml.wait();
1800       }
1801     }
1802     // The current thread could have been suspended again. We have to check for
1803     // suspend after restoring the saved state. Without this the current thread
1804     // might return to _thread_in_Java and execute bytecode.
1805     set_thread_state_fence(state);
1806 
1807     if (state != _thread_in_native) {
1808       SafepointMechanism::process_if_requested(this);
1809     }
1810     // A handshake for obj. deoptimization suspend could have been processed so
1811     // we must check after processing.
1812   } while (is_obj_deopt_suspend());
1813 }
1814 
1815 #ifdef ASSERT
1816 // Verify the JavaThread has not yet been published in the Threads::list, and
1817 // hence doesn't need protection from concurrent access at this stage.
1818 void JavaThread::verify_not_published() {
1819   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1820   // since an unpublished JavaThread doesn't participate in the
1821   // Thread-SMR protocol for keeping a ThreadsList alive.
1822   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1823 }
1824 #endif
1825 
1826 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1827 // pending, when _suspend_flags is non-zero or when we need to process a stack
1828 // watermark. Also check for pending async exceptions (except unsafe access error).
1829 // Note only the native==>Java barriers can call this function when thread state
1830 // is _thread_in_native_trans.
1831 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1832   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1833   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1834 
1835   thread->set_thread_state(_thread_in_vm);
1836 
1837   // Enable WXWrite: called directly from interpreter native wrapper.
1838   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1839 
1840   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1841 
1842   // After returning from native, it could be that the stack frames are not
1843   // yet safe to use. We catch such situations in the subsequent stack watermark
1844   // barrier, which will trap unsafe stack frames.
1845   StackWatermarkSet::before_unwind(thread);
1846 }
1847 
1848 #ifndef PRODUCT
1849 // Deoptimization
1850 // Function for testing deoptimization
1851 void JavaThread::deoptimize() {
1852   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1853   bool deopt = false;           // Dump stack only if a deopt actually happens.
1854   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1855   // Iterate over all frames in the thread and deoptimize
1856   for (; !fst.is_done(); fst.next()) {
1857     if (fst.current()->can_be_deoptimized()) {
1858 
1859       if (only_at) {
1860         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1861         // consists of comma or carriage return separated numbers so
1862         // search for the current bci in that string.
1863         address pc = fst.current()->pc();
1864         nmethod* nm =  (nmethod*) fst.current()->cb();
1865         ScopeDesc* sd = nm->scope_desc_at(pc);
1866         char buffer[8];
1867         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1868         size_t len = strlen(buffer);
1869         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1870         while (found != NULL) {
1871           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1872               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1873             // Check that the bci found is bracketed by terminators.
1874             break;
1875           }
1876           found = strstr(found + 1, buffer);
1877         }
1878         if (!found) {
1879           continue;
1880         }
1881       }
1882 
1883       if (DebugDeoptimization && !deopt) {
1884         deopt = true; // One-time only print before deopt
1885         tty->print_cr("[BEFORE Deoptimization]");
1886         trace_frames();
1887         trace_stack();
1888       }
1889       Deoptimization::deoptimize(this, *fst.current());
1890     }
1891   }
1892 
1893   if (DebugDeoptimization && deopt) {
1894     tty->print_cr("[AFTER Deoptimization]");
1895     trace_frames();
1896   }
1897 }
1898 
1899 
1900 // Make zombies
1901 void JavaThread::make_zombies() {
1902   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1903     if (fst.current()->can_be_deoptimized()) {
1904       // it is a Java nmethod
1905       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1906       nm->make_not_entrant();
1907     }
1908   }
1909 }
1910 #endif // PRODUCT
1911 
1912 
1913 void JavaThread::deoptimize_marked_methods() {
1914   if (!has_last_Java_frame()) return;
1915   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1916   for (; !fst.is_done(); fst.next()) {
1917     if (fst.current()->should_be_deoptimized()) {
1918       Deoptimization::deoptimize(this, *fst.current());
1919     }
1920   }
1921 }
1922 
1923 #ifdef ASSERT
1924 void JavaThread::verify_frame_info() {
1925   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1926          (has_last_Java_frame() && java_call_counter() > 0),
1927          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1928          has_last_Java_frame() ? "true" : "false", java_call_counter());
1929 }
1930 #endif
1931 
1932 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1933   // Verify that the deferred card marks have been flushed.
1934   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1935 
1936   // Traverse the GCHandles
1937   Thread::oops_do_no_frames(f, cf);
1938 
1939   DEBUG_ONLY(verify_frame_info();)
1940 
1941   if (has_last_Java_frame()) {
1942     // Traverse the monitor chunks
1943     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1944       chunk->oops_do(f);
1945     }
1946   }
1947 
1948   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1949   // If we have deferred set_locals there might be oops waiting to be
1950   // written
1951   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1952   if (list != NULL) {
1953     for (int i = 0; i < list->length(); i++) {
1954       list->at(i)->oops_do(f);
1955     }
1956   }
1957 
1958   // Traverse instance variables at the end since the GC may be moving things
1959   // around using this function
1960   f->do_oop((oop*) &_vm_result);
1961   f->do_oop((oop*) &_exception_oop);
1962   f->do_oop((oop*) &_pending_async_exception);
1963 #if INCLUDE_JVMCI
1964   f->do_oop((oop*) &_jvmci_reserved_oop0);
1965 #endif
1966 
1967   if (jvmti_thread_state() != NULL) {
1968     jvmti_thread_state()->oops_do(f, cf);
1969   }
1970 }
1971 
1972 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1973   if (!has_last_Java_frame()) {
1974     return;
1975   }
1976   // Finish any pending lazy GC activity for the frames
1977   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1978   // Traverse the execution stack
1979   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1980     fst.current()->oops_do(f, cf, fst.register_map());
1981   }
1982 }
1983 
1984 #ifdef ASSERT
1985 void JavaThread::verify_states_for_handshake() {
1986   // This checks that the thread has a correct frame state during a handshake.
1987   verify_frame_info();
1988 }
1989 #endif
1990 
1991 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1992   DEBUG_ONLY(verify_frame_info();)
1993 
1994   if (has_last_Java_frame()) {
1995     // Traverse the execution stack
1996     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1997       fst.current()->nmethods_do(cf);
1998     }
1999   }
2000 
2001   if (jvmti_thread_state() != NULL) {
2002     jvmti_thread_state()->nmethods_do(cf);
2003   }
2004 }
2005 
2006 void JavaThread::metadata_do(MetadataClosure* f) {
2007   if (has_last_Java_frame()) {
2008     // Traverse the execution stack to call f() on the methods in the stack
2009     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2010       fst.current()->metadata_do(f);
2011     }
2012   } else if (is_Compiler_thread()) {
2013     // need to walk ciMetadata in current compile tasks to keep alive.
2014     CompilerThread* ct = (CompilerThread*)this;
2015     if (ct->env() != NULL) {
2016       ct->env()->metadata_do(f);
2017     }
2018     CompileTask* task = ct->task();
2019     if (task != NULL) {
2020       task->metadata_do(f);
2021     }
2022   }
2023 }
2024 
2025 // Printing
2026 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2027   switch (_thread_state) {
2028   case _thread_uninitialized:     return "_thread_uninitialized";
2029   case _thread_new:               return "_thread_new";
2030   case _thread_new_trans:         return "_thread_new_trans";
2031   case _thread_in_native:         return "_thread_in_native";
2032   case _thread_in_native_trans:   return "_thread_in_native_trans";
2033   case _thread_in_vm:             return "_thread_in_vm";
2034   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2035   case _thread_in_Java:           return "_thread_in_Java";
2036   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2037   case _thread_blocked:           return "_thread_blocked";
2038   case _thread_blocked_trans:     return "_thread_blocked_trans";
2039   default:                        return "unknown thread state";
2040   }
2041 }
2042 
2043 #ifndef PRODUCT
2044 void JavaThread::print_thread_state_on(outputStream *st) const {
2045   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2046 };
2047 #endif // PRODUCT
2048 
2049 // Called by Threads::print() for VM_PrintThreads operation
2050 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2051   st->print_raw("\"");
2052   st->print_raw(name());
2053   st->print_raw("\" ");
2054   oop thread_oop = threadObj();
2055   if (thread_oop != NULL) {
2056     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2057     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2058     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2059   }
2060   Thread::print_on(st, print_extended_info);
2061   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2062   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2063   if (thread_oop != NULL) {
2064     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2065   }
2066 #ifndef PRODUCT
2067   _safepoint_state->print_on(st);
2068 #endif // PRODUCT
2069   if (is_Compiler_thread()) {
2070     CompileTask *task = ((CompilerThread*)this)->task();
2071     if (task != NULL) {
2072       st->print("   Compiling: ");
2073       task->print(st, NULL, true, false);
2074     } else {
2075       st->print("   No compile task");
2076     }
2077     st->cr();
2078   }
2079 }
2080 
2081 void JavaThread::print() const { print_on(tty); }
2082 
2083 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2084   st->print("%s", get_thread_name_string(buf, buflen));
2085 }
2086 
2087 // Called by fatal error handler. The difference between this and
2088 // JavaThread::print() is that we can't grab lock or allocate memory.
2089 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2090   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
2091   oop thread_obj = threadObj();
2092   if (thread_obj != NULL) {
2093     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2094   }
2095   st->print(" [");
2096   st->print("%s", _get_thread_state_name(_thread_state));
2097   if (osthread()) {
2098     st->print(", id=%d", osthread()->thread_id());
2099   }
2100   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2101             p2i(stack_end()), p2i(stack_base()));
2102   st->print("]");
2103 
2104   ThreadsSMRSupport::print_info_on(this, st);
2105   return;
2106 }
2107 
2108 
2109 // Verification
2110 
2111 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2112   // ignore if there is no stack
2113   if (!has_last_Java_frame()) return;
2114   // traverse the stack frames. Starts from top frame.
2115   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2116     frame* fr = fst.current();
2117     f(fr, fst.register_map());
2118   }
2119 }
2120 
2121 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2122 
2123 void JavaThread::verify() {
2124   // Verify oops in the thread.
2125   oops_do(&VerifyOopClosure::verify_oop, NULL);
2126 
2127   // Verify the stack frames.
2128   frames_do(frame_verify);
2129 }
2130 
2131 // CR 6300358 (sub-CR 2137150)
2132 // Most callers of this method assume that it can't return NULL but a
2133 // thread may not have a name whilst it is in the process of attaching to
2134 // the VM - see CR 6412693, and there are places where a JavaThread can be
2135 // seen prior to having its threadObj set (e.g., JNI attaching threads and
2136 // if vm exit occurs during initialization). These cases can all be accounted
2137 // for such that this method never returns NULL.
2138 const char* JavaThread::name() const  {
2139   if (Thread::is_JavaThread_protected(this)) {
2140     // The target JavaThread is protected so get_thread_name_string() is safe:
2141     return get_thread_name_string();
2142   }
2143 
2144   // The target JavaThread is not protected so we return the default:
2145   return Thread::name();
2146 }
2147 
2148 // Returns a non-NULL representation of this thread's name, or a suitable
2149 // descriptive string if there is no set name.
2150 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2151   const char* name_str;
2152   oop thread_obj = threadObj();
2153   if (thread_obj != NULL) {
2154     oop name = java_lang_Thread::name(thread_obj);
2155     if (name != NULL) {
2156       if (buf == NULL) {
2157         name_str = java_lang_String::as_utf8_string(name);
2158       } else {
2159         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2160       }
2161     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2162       name_str = "<no-name - thread is attaching>";
2163     } else {
2164       name_str = "<un-named>";
2165     }
2166   } else {
2167     name_str = Thread::name();
2168   }
2169   assert(name_str != NULL, "unexpected NULL thread name");
2170   return name_str;
2171 }
2172 
2173 // Helper to extract the name from the thread oop for logging.
2174 const char* JavaThread::name_for(oop thread_obj) {
2175   assert(thread_obj != NULL, "precondition");
2176   oop name = java_lang_Thread::name(thread_obj);
2177   const char* name_str;
2178   if (name != NULL) {
2179     name_str = java_lang_String::as_utf8_string(name);
2180   } else {
2181     name_str = "<un-named>";
2182   }
2183   return name_str;
2184 }
2185 
2186 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2187 
2188   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2189   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
2190   // Link Java Thread object <-> C++ Thread
2191 
2192   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2193   // and put it into a new Handle.  The Handle "thread_oop" can then
2194   // be used to pass the C++ thread object to other methods.
2195 
2196   // Set the Java level thread object (jthread) field of the
2197   // new thread (a JavaThread *) to C++ thread object using the
2198   // "thread_oop" handle.
2199 
2200   // Set the thread field (a JavaThread *) of the
2201   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2202 
2203   Handle thread_oop(Thread::current(),
2204                     JNIHandles::resolve_non_null(jni_thread));
2205   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2206          "must be initialized");
2207   set_threadObj(thread_oop());
2208   java_lang_Thread::set_thread(thread_oop(), this);
2209 
2210   if (prio == NoPriority) {
2211     prio = java_lang_Thread::priority(thread_oop());
2212     assert(prio != NoPriority, "A valid priority should be present");
2213   }
2214 
2215   // Push the Java priority down to the native thread; needs Threads_lock
2216   Thread::set_priority(this, prio);
2217 
2218   // Add the new thread to the Threads list and set it in motion.
2219   // We must have threads lock in order to call Threads::add.
2220   // It is crucial that we do not block before the thread is
2221   // added to the Threads list for if a GC happens, then the java_thread oop
2222   // will not be visited by GC.
2223   Threads::add(this);
2224 }
2225 
2226 oop JavaThread::current_park_blocker() {
2227   // Support for JSR-166 locks
2228   oop thread_oop = threadObj();
2229   if (thread_oop != NULL) {
2230     return java_lang_Thread::park_blocker(thread_oop);
2231   }
2232   return NULL;
2233 }
2234 
2235 
2236 void JavaThread::print_stack_on(outputStream* st) {
2237   if (!has_last_Java_frame()) return;
2238 
2239   Thread* current_thread = Thread::current();
2240   ResourceMark rm(current_thread);
2241   HandleMark hm(current_thread);
2242 
2243   RegisterMap reg_map(this);
2244   vframe* start_vf = last_java_vframe(&reg_map);
2245   int count = 0;
2246   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
2247     if (f->is_java_frame()) {
2248       javaVFrame* jvf = javaVFrame::cast(f);
2249       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2250 
2251       // Print out lock information
2252       if (JavaMonitorsInStackTrace) {
2253         jvf->print_lock_info_on(st, count);
2254       }
2255     } else {
2256       // Ignore non-Java frames
2257     }
2258 
2259     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
2260     count++;
2261     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
2262   }
2263 }
2264 
2265 
2266 // JVMTI PopFrame support
2267 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2268   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2269   if (in_bytes(size_in_bytes) != 0) {
2270     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2271     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2272     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2273   }
2274 }
2275 
2276 void* JavaThread::popframe_preserved_args() {
2277   return _popframe_preserved_args;
2278 }
2279 
2280 ByteSize JavaThread::popframe_preserved_args_size() {
2281   return in_ByteSize(_popframe_preserved_args_size);
2282 }
2283 
2284 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2285   int sz = in_bytes(popframe_preserved_args_size());
2286   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2287   return in_WordSize(sz / wordSize);
2288 }
2289 
2290 void JavaThread::popframe_free_preserved_args() {
2291   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2292   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
2293   _popframe_preserved_args = NULL;
2294   _popframe_preserved_args_size = 0;
2295 }
2296 
2297 #ifndef PRODUCT
2298 
2299 void JavaThread::trace_frames() {
2300   tty->print_cr("[Describe stack]");
2301   int frame_no = 1;
2302   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2303     tty->print("  %d. ", frame_no++);
2304     fst.current()->print_value_on(tty, this);
2305     tty->cr();
2306   }
2307 }
2308 
2309 class PrintAndVerifyOopClosure: public OopClosure {
2310  protected:
2311   template <class T> inline void do_oop_work(T* p) {
2312     oop obj = RawAccess<>::oop_load(p);
2313     if (obj == NULL) return;
2314     tty->print(INTPTR_FORMAT ": ", p2i(p));
2315     if (oopDesc::is_oop_or_null(obj)) {
2316       if (obj->is_objArray()) {
2317         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
2318       } else {
2319         obj->print();
2320       }
2321     } else {
2322       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
2323     }
2324     tty->cr();
2325   }
2326  public:
2327   virtual void do_oop(oop* p) { do_oop_work(p); }
2328   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
2329 };
2330 
2331 #ifdef ASSERT
2332 // Print or validate the layout of stack frames
2333 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2334   ResourceMark rm;
2335   PreserveExceptionMark pm(this);
2336   FrameValues values;
2337   int frame_no = 0;
2338   for (StackFrameStream fst(this, false /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
2339     fst.current()->describe(values, ++frame_no);
2340     if (depth == frame_no) break;
2341   }
2342   if (validate_only) {
2343     values.validate();
2344   } else {
2345     tty->print_cr("[Describe stack layout]");
2346     values.print(this);
2347   }
2348 }
2349 #endif
2350 
2351 void JavaThread::trace_stack_from(vframe* start_vf) {
2352   ResourceMark rm;
2353   int vframe_no = 1;
2354   for (vframe* f = start_vf; f; f = f->sender()) {
2355     if (f->is_java_frame()) {
2356       javaVFrame::cast(f)->print_activation(vframe_no++);
2357     } else {
2358       f->print();
2359     }
2360     if (vframe_no > StackPrintLimit) {
2361       tty->print_cr("...<more frames>...");
2362       return;
2363     }
2364   }
2365 }
2366 
2367 
2368 void JavaThread::trace_stack() {
2369   if (!has_last_Java_frame()) return;
2370   Thread* current_thread = Thread::current();
2371   ResourceMark rm(current_thread);
2372   HandleMark hm(current_thread);
2373   RegisterMap reg_map(this);
2374   trace_stack_from(last_java_vframe(&reg_map));
2375 }
2376 
2377 
2378 #endif // PRODUCT
2379 
2380 
2381 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2382   assert(reg_map != NULL, "a map must be given");
2383   frame f = last_frame();
2384   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2385     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2386   }
2387   return NULL;
2388 }
2389 
2390 
2391 Klass* JavaThread::security_get_caller_class(int depth) {
2392   vframeStream vfst(this);
2393   vfst.security_get_caller_frame(depth);
2394   if (!vfst.at_end()) {
2395     return vfst.method()->method_holder();
2396   }
2397   return NULL;
2398 }
2399 
2400 // java.lang.Thread.sleep support
2401 // Returns true if sleep time elapsed as expected, and false
2402 // if the thread was interrupted.
2403 bool JavaThread::sleep(jlong millis) {
2404   assert(this == Thread::current(),  "thread consistency check");
2405 
2406   ParkEvent * const slp = this->_SleepEvent;
2407   // Because there can be races with thread interruption sending an unpark()
2408   // to the event, we explicitly reset it here to avoid an immediate return.
2409   // The actual interrupt state will be checked before we park().
2410   slp->reset();
2411   // Thread interruption establishes a happens-before ordering in the
2412   // Java Memory Model, so we need to ensure we synchronize with the
2413   // interrupt state.
2414   OrderAccess::fence();
2415 
2416   jlong prevtime = os::javaTimeNanos();
2417 
2418   for (;;) {
2419     // interruption has precedence over timing out
2420     if (this->is_interrupted(true)) {
2421       return false;
2422     }
2423 
2424     if (millis <= 0) {
2425       return true;
2426     }
2427 
2428     {
2429       ThreadBlockInVM tbivm(this);
2430       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2431       slp->park(millis);
2432     }
2433 
2434     // Update elapsed time tracking
2435     jlong newtime = os::javaTimeNanos();
2436     if (newtime - prevtime < 0) {
2437       // time moving backwards, should only happen if no monotonic clock
2438       // not a guarantee() because JVM should not abort on kernel/glibc bugs
2439       assert(false,
2440              "unexpected time moving backwards detected in JavaThread::sleep()");
2441     } else {
2442       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2443     }
2444     prevtime = newtime;
2445   }
2446 }
2447 
2448 
2449 // ======= Threads ========
2450 
2451 // The Threads class links together all active threads, and provides
2452 // operations over all threads. It is protected by the Threads_lock,
2453 // which is also used in other global contexts like safepointing.
2454 // ThreadsListHandles are used to safely perform operations on one
2455 // or more threads without the risk of the thread exiting during the
2456 // operation.
2457 //
2458 // Note: The Threads_lock is currently more widely used than we
2459 // would like. We are actively migrating Threads_lock uses to other
2460 // mechanisms in order to reduce Threads_lock contention.
2461 
2462 int         Threads::_number_of_threads = 0;
2463 int         Threads::_number_of_non_daemon_threads = 0;
2464 int         Threads::_return_code = 0;
2465 uintx       Threads::_thread_claim_token = 1; // Never zero.
2466 size_t      JavaThread::_stack_size_at_create = 0;
2467 
2468 #ifdef ASSERT
2469 bool        Threads::_vm_complete = false;
2470 #endif
2471 
2472 // All NonJavaThreads (i.e., every non-JavaThread in the system).
2473 void Threads::non_java_threads_do(ThreadClosure* tc) {
2474   NoSafepointVerifier nsv;
2475   for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) {
2476     tc->do_thread(njti.current());
2477   }
2478 }
2479 
2480 // All JavaThreads
2481 #define ALL_JAVA_THREADS(X) \
2482   for (JavaThread* X : *ThreadsSMRSupport::get_java_thread_list())
2483 
2484 // All JavaThreads
2485 void Threads::java_threads_do(ThreadClosure* tc) {
2486   assert_locked_or_safepoint(Threads_lock);
2487   // ALL_JAVA_THREADS iterates through all JavaThreads.
2488   ALL_JAVA_THREADS(p) {
2489     tc->do_thread(p);
2490   }
2491 }
2492 
2493 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
2494   assert_locked_or_safepoint(Threads_lock);
2495   java_threads_do(tc);
2496   tc->do_thread(VMThread::vm_thread());
2497 }
2498 
2499 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
2500 void Threads::threads_do(ThreadClosure* tc) {
2501   assert_locked_or_safepoint(Threads_lock);
2502   java_threads_do(tc);
2503   non_java_threads_do(tc);
2504 }
2505 
2506 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
2507   uintx claim_token = Threads::thread_claim_token();
2508   ALL_JAVA_THREADS(p) {
2509     if (p->claim_threads_do(is_par, claim_token)) {
2510       tc->do_thread(p);
2511     }
2512   }
2513   VMThread* vmt = VMThread::vm_thread();
2514   if (vmt->claim_threads_do(is_par, claim_token)) {
2515     tc->do_thread(vmt);
2516   }
2517 }
2518 
2519 // The system initialization in the library has three phases.
2520 //
2521 // Phase 1: java.lang.System class initialization
2522 //     java.lang.System is a primordial class loaded and initialized
2523 //     by the VM early during startup.  java.lang.System.<clinit>
2524 //     only does registerNatives and keeps the rest of the class
2525 //     initialization work later until thread initialization completes.
2526 //
2527 //     System.initPhase1 initializes the system properties, the static
2528 //     fields in, out, and err. Set up java signal handlers, OS-specific
2529 //     system settings, and thread group of the main thread.
2530 static void call_initPhase1(TRAPS) {
2531   Klass* klass = vmClasses::System_klass();
2532   JavaValue result(T_VOID);
2533   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
2534                                          vmSymbols::void_method_signature(), CHECK);
2535 }
2536 
2537 // Phase 2. Module system initialization
2538 //     This will initialize the module system.  Only java.base classes
2539 //     can be loaded until phase 2 completes.
2540 //
2541 //     Call System.initPhase2 after the compiler initialization and jsr292
2542 //     classes get initialized because module initialization runs a lot of java
2543 //     code, that for performance reasons, should be compiled.  Also, this will
2544 //     enable the startup code to use lambda and other language features in this
2545 //     phase and onward.
2546 //
2547 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
2548 static void call_initPhase2(TRAPS) {
2549   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
2550 
2551   Klass* klass = vmClasses::System_klass();
2552 
2553   JavaValue result(T_INT);
2554   JavaCallArguments args;
2555   args.push_int(DisplayVMOutputToStderr);
2556   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
2557   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
2558                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
2559   if (result.get_jint() != JNI_OK) {
2560     vm_exit_during_initialization(); // no message or exception
2561   }
2562 
2563   universe_post_module_init();
2564 }
2565 
2566 // Phase 3. final setup - set security manager, system class loader and TCCL
2567 //
2568 //     This will instantiate and set the security manager, set the system class
2569 //     loader as well as the thread context class loader.  The security manager
2570 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
2571 //     other modules or the application's classpath.
2572 static void call_initPhase3(TRAPS) {
2573   Klass* klass = vmClasses::System_klass();
2574   JavaValue result(T_VOID);
2575   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
2576                                          vmSymbols::void_method_signature(), CHECK);
2577 }
2578 
2579 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
2580   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
2581 
2582   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2583     create_vm_init_libraries();
2584   }
2585 
2586   initialize_class(vmSymbols::java_lang_String(), CHECK);
2587 
2588   // Inject CompactStrings value after the static initializers for String ran.
2589   java_lang_String::set_compact_strings(CompactStrings);
2590 
2591   // Initialize java_lang.System (needed before creating the thread)
2592   initialize_class(vmSymbols::java_lang_System(), CHECK);
2593   // The VM creates & returns objects of this class. Make sure it's initialized.
2594   initialize_class(vmSymbols::java_lang_Class(), CHECK);
2595   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
2596   Handle thread_group = create_initial_thread_group(CHECK);
2597   Universe::set_main_thread_group(thread_group());
2598   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
2599   create_initial_thread(thread_group, main_thread, CHECK);
2600 
2601   // The VM creates objects of this class.
2602   initialize_class(vmSymbols::java_lang_Module(), CHECK);
2603 
2604 #ifdef ASSERT
2605   InstanceKlass *k = vmClasses::UnsafeConstants_klass();
2606   assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized");
2607 #endif
2608 
2609   // initialize the hardware-specific constants needed by Unsafe
2610   initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK);
2611   jdk_internal_misc_UnsafeConstants::set_unsafe_constants();
2612 
2613   // The VM preresolves methods to these classes. Make sure that they get initialized
2614   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
2615   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
2616 
2617   // Phase 1 of the system initialization in the library, java.lang.System class initialization
2618   call_initPhase1(CHECK);
2619 
2620   // Get the Java runtime name, version, and vendor info after java.lang.System is initialized.
2621   // Some values are actually configure-time constants but some can be set via the jlink tool and
2622   // so must be read dynamically. We treat them all the same.
2623   InstanceKlass* ik = SystemDictionary::find_instance_klass(vmSymbols::java_lang_VersionProps(),
2624                                                             Handle(), Handle());
2625   {
2626     ResourceMark rm(main_thread);
2627     JDK_Version::set_java_version(get_java_version_info(ik, vmSymbols::java_version_name()));
2628 
2629     JDK_Version::set_runtime_name(get_java_version_info(ik, vmSymbols::java_runtime_name_name()));
2630 
2631     JDK_Version::set_runtime_version(get_java_version_info(ik, vmSymbols::java_runtime_version_name()));
2632 
2633     JDK_Version::set_runtime_vendor_version(get_java_version_info(ik, vmSymbols::java_runtime_vendor_version_name()));
2634 
2635     JDK_Version::set_runtime_vendor_vm_bug_url(get_java_version_info(ik, vmSymbols::java_runtime_vendor_vm_bug_url_name()));
2636   }
2637 
2638   // an instance of OutOfMemory exception has been allocated earlier
2639   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
2640   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
2641   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
2642   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
2643   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
2644   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
2645   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
2646   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
2647 }
2648 
2649 void Threads::initialize_jsr292_core_classes(TRAPS) {
2650   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
2651 
2652   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
2653   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
2654   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
2655   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
2656 }
2657 
2658 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2659   extern void JDK_Version_init();
2660 
2661   // Preinitialize version info.
2662   VM_Version::early_initialize();
2663 
2664   // Check version
2665   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2666 
2667   // Initialize library-based TLS
2668   ThreadLocalStorage::init();
2669 
2670   // Initialize the output stream module
2671   ostream_init();
2672 
2673   // Process java launcher properties.
2674   Arguments::process_sun_java_launcher_properties(args);
2675 
2676   // Initialize the os module
2677   os::init();
2678 
2679   MACOS_AARCH64_ONLY(os::current_thread_enable_wx(WXWrite));
2680 
2681   // Record VM creation timing statistics
2682   TraceVmCreationTime create_vm_timer;
2683   create_vm_timer.start();
2684 
2685   // Initialize system properties.
2686   Arguments::init_system_properties();
2687 
2688   // So that JDK version can be used as a discriminator when parsing arguments
2689   JDK_Version_init();
2690 
2691   // Update/Initialize System properties after JDK version number is known
2692   Arguments::init_version_specific_system_properties();
2693 
2694   // Make sure to initialize log configuration *before* parsing arguments
2695   LogConfiguration::initialize(create_vm_timer.begin_time());
2696 
2697   // Parse arguments
2698   // Note: this internally calls os::init_container_support()
2699   jint parse_result = Arguments::parse(args);
2700   if (parse_result != JNI_OK) return parse_result;
2701 
2702 #if INCLUDE_NMT
2703   // Initialize NMT right after argument parsing to keep the pre-NMT-init window small.
2704   MemTracker::initialize();
2705 #endif // INCLUDE_NMT
2706 
2707   os::init_before_ergo();
2708 
2709   jint ergo_result = Arguments::apply_ergo();
2710   if (ergo_result != JNI_OK) return ergo_result;
2711 
2712   // Final check of all ranges after ergonomics which may change values.
2713   if (!JVMFlagLimit::check_all_ranges()) {
2714     return JNI_EINVAL;
2715   }
2716 
2717   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
2718   bool constraint_result = JVMFlagLimit::check_all_constraints(JVMFlagConstraintPhase::AfterErgo);
2719   if (!constraint_result) {
2720     return JNI_EINVAL;
2721   }
2722 
2723   if (PauseAtStartup) {
2724     os::pause();
2725   }
2726 
2727   HOTSPOT_VM_INIT_BEGIN();
2728 
2729   // Timing (must come after argument parsing)
2730   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
2731 
2732   // Initialize the os module after parsing the args
2733   jint os_init_2_result = os::init_2();
2734   if (os_init_2_result != JNI_OK) return os_init_2_result;
2735 
2736 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
2737   // Initialize assert poison page mechanism.
2738   if (ShowRegistersOnAssert) {
2739     initialize_assert_poison();
2740   }
2741 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
2742 
2743   SafepointMechanism::initialize();
2744 
2745   jint adjust_after_os_result = Arguments::adjust_after_os();
2746   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
2747 
2748   // Initialize output stream logging
2749   ostream_init_log();
2750 
2751   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2752   // Must be before create_vm_init_agents()
2753   if (Arguments::init_libraries_at_startup()) {
2754     convert_vm_init_libraries_to_agents();
2755   }
2756 
2757   // Launch -agentlib/-agentpath and converted -Xrun agents
2758   if (Arguments::init_agents_at_startup()) {
2759     create_vm_init_agents();
2760   }
2761 
2762   // Initialize Threads state
2763   _number_of_threads = 0;
2764   _number_of_non_daemon_threads = 0;
2765 
2766   // Initialize global data structures and create system classes in heap
2767   vm_init_globals();
2768 
2769 #if INCLUDE_JVMCI
2770   if (JVMCICounterSize > 0) {
2771     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI);
2772     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
2773   } else {
2774     JavaThread::_jvmci_old_thread_counters = NULL;
2775   }
2776 #endif // INCLUDE_JVMCI
2777 
2778   // Initialize OopStorage for threadObj
2779   _thread_oop_storage = OopStorageSet::create_strong("Thread OopStorage", mtThread);
2780 
2781   // Attach the main thread to this os thread
2782   JavaThread* main_thread = new JavaThread();
2783   main_thread->set_thread_state(_thread_in_vm);
2784   main_thread->initialize_thread_current();
2785   // must do this before set_active_handles
2786   main_thread->record_stack_base_and_size();
2787   main_thread->register_thread_stack_with_NMT();
2788   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2789   MACOS_AARCH64_ONLY(main_thread->init_wx());
2790 
2791   if (!main_thread->set_as_starting_thread()) {
2792     vm_shutdown_during_initialization(
2793                                       "Failed necessary internal allocation. Out of swap space");
2794     main_thread->smr_delete();
2795     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2796     return JNI_ENOMEM;
2797   }
2798 
2799   // Enable guard page *after* os::create_main_thread(), otherwise it would
2800   // crash Linux VM, see notes in os_linux.cpp.
2801   main_thread->stack_overflow_state()->create_stack_guard_pages();
2802 
2803   // Initialize Java-Level synchronization subsystem
2804   ObjectMonitor::Initialize();
2805   ObjectSynchronizer::initialize();
2806 
2807   // Initialize global modules
2808   jint status = init_globals();
2809   if (status != JNI_OK) {
2810     main_thread->smr_delete();
2811     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2812     return status;
2813   }
2814 
2815   JFR_ONLY(Jfr::on_create_vm_1();)
2816 
2817   // Should be done after the heap is fully created
2818   main_thread->cache_global_variables();
2819 
2820   { MutexLocker mu(Threads_lock);
2821     Threads::add(main_thread);
2822   }
2823 
2824   // Any JVMTI raw monitors entered in onload will transition into
2825   // real raw monitor. VM is setup enough here for raw monitor enter.
2826   JvmtiExport::transition_pending_onload_raw_monitors();
2827 
2828   // Create the VMThread
2829   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
2830 
2831     VMThread::create();
2832     Thread* vmthread = VMThread::vm_thread();
2833 
2834     if (!os::create_thread(vmthread, os::vm_thread)) {
2835       vm_exit_during_initialization("Cannot create VM thread. "
2836                                     "Out of system resources.");
2837     }
2838 
2839     // Wait for the VM thread to become ready, and VMThread::run to initialize
2840     // Monitors can have spurious returns, must always check another state flag
2841     {
2842       MonitorLocker ml(Notify_lock);
2843       os::start_thread(vmthread);
2844       while (vmthread->active_handles() == NULL) {
2845         ml.wait();
2846       }
2847     }
2848   }
2849 
2850   assert(Universe::is_fully_initialized(), "not initialized");
2851   if (VerifyDuringStartup) {
2852     // Make sure we're starting with a clean slate.
2853     VM_Verify verify_op;
2854     VMThread::execute(&verify_op);
2855   }
2856 
2857   // We need this to update the java.vm.info property in case any flags used
2858   // to initially define it have been changed. This is needed for both CDS
2859   // since UseSharedSpaces may be changed after java.vm.info
2860   // is initially computed. See Abstract_VM_Version::vm_info_string().
2861   // This update must happen before we initialize the java classes, but
2862   // after any initialization logic that might modify the flags.
2863   Arguments::update_vm_info_property(VM_Version::vm_info_string());
2864 
2865   JavaThread* THREAD = JavaThread::current(); // For exception macros.
2866   HandleMark hm(THREAD);
2867 
2868   // Always call even when there are not JVMTI environments yet, since environments
2869   // may be attached late and JVMTI must track phases of VM execution
2870   JvmtiExport::enter_early_start_phase();
2871 
2872   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2873   JvmtiExport::post_early_vm_start();
2874 
2875   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
2876 
2877   quicken_jni_functions();
2878 
2879   // No more stub generation allowed after that point.
2880   StubCodeDesc::freeze();
2881 
2882   // Set flag that basic initialization has completed. Used by exceptions and various
2883   // debug stuff, that does not work until all basic classes have been initialized.
2884   set_init_completed();
2885 
2886   LogConfiguration::post_initialize();
2887   Metaspace::post_initialize();
2888 
2889   HOTSPOT_VM_INIT_END();
2890 
2891   // record VM initialization completion time
2892 #if INCLUDE_MANAGEMENT
2893   Management::record_vm_init_completed();
2894 #endif // INCLUDE_MANAGEMENT
2895 
2896   // Signal Dispatcher needs to be started before VMInit event is posted
2897   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
2898 
2899   // Start Attach Listener if +StartAttachListener or it can't be started lazily
2900   if (!DisableAttachMechanism) {
2901     AttachListener::vm_start();
2902     if (StartAttachListener || AttachListener::init_at_startup()) {
2903       AttachListener::init();
2904     }
2905   }
2906 
2907   // Launch -Xrun agents
2908   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
2909   // back-end can launch with -Xdebug -Xrunjdwp.
2910   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
2911     create_vm_init_libraries();
2912   }
2913 
2914   Chunk::start_chunk_pool_cleaner_task();
2915 
2916   // Start the service thread
2917   // The service thread enqueues JVMTI deferred events and does various hashtable
2918   // and other cleanups.  Needs to start before the compilers start posting events.
2919   ServiceThread::initialize();
2920 
2921   // Start the monitor deflation thread:
2922   MonitorDeflationThread::initialize();
2923 
2924   // initialize compiler(s)
2925 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
2926 #if INCLUDE_JVMCI
2927   bool force_JVMCI_intialization = false;
2928   if (EnableJVMCI) {
2929     // Initialize JVMCI eagerly when it is explicitly requested.
2930     // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled.
2931     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig;
2932 
2933     if (!force_JVMCI_intialization) {
2934       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
2935       // compilations via JVMCI will not actually block until JVMCI is initialized.
2936       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
2937     }
2938   }
2939 #endif
2940   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
2941   // Postpone completion of compiler initialization to after JVMCI
2942   // is initialized to avoid timeouts of blocking compilations.
2943   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
2944     CompileBroker::compilation_init_phase2();
2945   }
2946 #endif
2947 
2948   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
2949   // It is done after compilers are initialized, because otherwise compilations of
2950   // signature polymorphic MH intrinsics can be missed
2951   // (see SystemDictionary::find_method_handle_intrinsic).
2952   initialize_jsr292_core_classes(CHECK_JNI_ERR);
2953 
2954   // This will initialize the module system.  Only java.base classes can be
2955   // loaded until phase 2 completes
2956   call_initPhase2(CHECK_JNI_ERR);
2957 
2958   JFR_ONLY(Jfr::on_create_vm_2();)
2959 
2960   // Always call even when there are not JVMTI environments yet, since environments
2961   // may be attached late and JVMTI must track phases of VM execution
2962   JvmtiExport::enter_start_phase();
2963 
2964   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2965   JvmtiExport::post_vm_start();
2966 
2967   // Final system initialization including security manager and system class loader
2968   call_initPhase3(CHECK_JNI_ERR);
2969 
2970   // cache the system and platform class loaders
2971   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
2972 
2973 #if INCLUDE_CDS
2974   // capture the module path info from the ModuleEntryTable
2975   ClassLoader::initialize_module_path(THREAD);
2976   if (HAS_PENDING_EXCEPTION) {
2977     java_lang_Throwable::print(PENDING_EXCEPTION, tty);
2978     vm_exit_during_initialization("ClassLoader::initialize_module_path() failed unexpectedly");
2979   }
2980 #endif
2981 
2982 #if INCLUDE_JVMCI
2983   if (force_JVMCI_intialization) {
2984     JVMCI::initialize_compiler(CHECK_JNI_ERR);
2985     CompileBroker::compilation_init_phase2();
2986   }
2987 #endif
2988 
2989   // Always call even when there are not JVMTI environments yet, since environments
2990   // may be attached late and JVMTI must track phases of VM execution
2991   JvmtiExport::enter_live_phase();
2992 
2993   // Make perfmemory accessible
2994   PerfMemory::set_accessible(true);
2995 
2996   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
2997   JvmtiExport::post_vm_initialized();
2998 
2999   JFR_ONLY(Jfr::on_create_vm_3();)
3000 
3001 #if INCLUDE_MANAGEMENT
3002   Management::initialize(THREAD);
3003 
3004   if (HAS_PENDING_EXCEPTION) {
3005     // management agent fails to start possibly due to
3006     // configuration problem and is responsible for printing
3007     // stack trace if appropriate. Simply exit VM.
3008     vm_exit(1);
3009   }
3010 #endif // INCLUDE_MANAGEMENT
3011 
3012   StatSampler::engage();
3013   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3014 
3015 #if INCLUDE_RTM_OPT
3016   RTMLockingCounters::init();
3017 #endif
3018 
3019   call_postVMInitHook(THREAD);
3020   // The Java side of PostVMInitHook.run must deal with all
3021   // exceptions and provide means of diagnosis.
3022   if (HAS_PENDING_EXCEPTION) {
3023     CLEAR_PENDING_EXCEPTION;
3024   }
3025 
3026   {
3027     MutexLocker ml(PeriodicTask_lock);
3028     // Make sure the WatcherThread can be started by WatcherThread::start()
3029     // or by dynamic enrollment.
3030     WatcherThread::make_startable();
3031     // Start up the WatcherThread if there are any periodic tasks
3032     // NOTE:  All PeriodicTasks should be registered by now. If they
3033     //   aren't, late joiners might appear to start slowly (we might
3034     //   take a while to process their first tick).
3035     if (PeriodicTask::num_tasks() > 0) {
3036       WatcherThread::start();
3037     }
3038   }
3039 
3040   create_vm_timer.end();
3041 #ifdef ASSERT
3042   _vm_complete = true;
3043 #endif
3044 
3045   if (DumpSharedSpaces) {
3046     MetaspaceShared::preload_and_dump();
3047     ShouldNotReachHere();
3048   }
3049 
3050   return JNI_OK;
3051 }
3052 
3053 // type for the Agent_OnLoad and JVM_OnLoad entry points
3054 extern "C" {
3055   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3056 }
3057 // Find a command line agent library and return its entry point for
3058 //         -agentlib:  -agentpath:   -Xrun
3059 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3060 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3061                                     const char *on_load_symbols[],
3062                                     size_t num_symbol_entries) {
3063   OnLoadEntry_t on_load_entry = NULL;
3064   void *library = NULL;
3065 
3066   if (!agent->valid()) {
3067     char buffer[JVM_MAXPATHLEN];
3068     char ebuf[1024] = "";
3069     const char *name = agent->name();
3070     const char *msg = "Could not find agent library ";
3071 
3072     // First check to see if agent is statically linked into executable
3073     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3074       library = agent->os_lib();
3075     } else if (agent->is_absolute_path()) {
3076       library = os::dll_load(name, ebuf, sizeof ebuf);
3077       if (library == NULL) {
3078         const char *sub_msg = " in absolute path, with error: ";
3079         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3080         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3081         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3082         // If we can't find the agent, exit.
3083         vm_exit_during_initialization(buf, NULL);
3084         FREE_C_HEAP_ARRAY(char, buf);
3085       }
3086     } else {
3087       // Try to load the agent from the standard dll directory
3088       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3089                              name)) {
3090         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3091       }
3092       if (library == NULL) { // Try the library path directory.
3093         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3094           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3095         }
3096         if (library == NULL) {
3097           const char *sub_msg = " on the library path, with error: ";
3098           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3099 
3100           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3101                        strlen(ebuf) + strlen(sub_msg2) + 1;
3102           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3103           if (!agent->is_instrument_lib()) {
3104             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3105           } else {
3106             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
3107           }
3108           // If we can't find the agent, exit.
3109           vm_exit_during_initialization(buf, NULL);
3110           FREE_C_HEAP_ARRAY(char, buf);
3111         }
3112       }
3113     }
3114     agent->set_os_lib(library);
3115     agent->set_valid();
3116   }
3117 
3118   // Find the OnLoad function.
3119   on_load_entry =
3120     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3121                                                           false,
3122                                                           on_load_symbols,
3123                                                           num_symbol_entries));
3124   return on_load_entry;
3125 }
3126 
3127 // Find the JVM_OnLoad entry point
3128 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3129   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3130   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3131 }
3132 
3133 // Find the Agent_OnLoad entry point
3134 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3135   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3136   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3137 }
3138 
3139 // For backwards compatibility with -Xrun
3140 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3141 // treated like -agentpath:
3142 // Must be called before agent libraries are created
3143 void Threads::convert_vm_init_libraries_to_agents() {
3144   AgentLibrary* agent;
3145   AgentLibrary* next;
3146 
3147   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3148     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3149     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3150 
3151     // If there is an JVM_OnLoad function it will get called later,
3152     // otherwise see if there is an Agent_OnLoad
3153     if (on_load_entry == NULL) {
3154       on_load_entry = lookup_agent_on_load(agent);
3155       if (on_load_entry != NULL) {
3156         // switch it to the agent list -- so that Agent_OnLoad will be called,
3157         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3158         Arguments::convert_library_to_agent(agent);
3159       } else {
3160         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3161       }
3162     }
3163   }
3164 }
3165 
3166 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3167 // Invokes Agent_OnLoad
3168 // Called very early -- before JavaThreads exist
3169 void Threads::create_vm_init_agents() {
3170   extern struct JavaVM_ main_vm;
3171   AgentLibrary* agent;
3172 
3173   JvmtiExport::enter_onload_phase();
3174 
3175   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3176     // CDS dumping does not support native JVMTI agent.
3177     // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified.
3178     if (Arguments::is_dumping_archive()) {
3179       if(!agent->is_instrument_lib()) {
3180         vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name());
3181       } else if (!AllowArchivingWithJavaAgent) {
3182         vm_exit_during_cds_dumping(
3183           "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping");
3184       }
3185     }
3186 
3187     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3188 
3189     if (on_load_entry != NULL) {
3190       // Invoke the Agent_OnLoad function
3191       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3192       if (err != JNI_OK) {
3193         vm_exit_during_initialization("agent library failed to init", agent->name());
3194       }
3195     } else {
3196       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3197     }
3198   }
3199 
3200   JvmtiExport::enter_primordial_phase();
3201 }
3202 
3203 extern "C" {
3204   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3205 }
3206 
3207 void Threads::shutdown_vm_agents() {
3208   // Send any Agent_OnUnload notifications
3209   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3210   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3211   extern struct JavaVM_ main_vm;
3212   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3213 
3214     // Find the Agent_OnUnload function.
3215     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3216                                                    os::find_agent_function(agent,
3217                                                    false,
3218                                                    on_unload_symbols,
3219                                                    num_symbol_entries));
3220 
3221     // Invoke the Agent_OnUnload function
3222     if (unload_entry != NULL) {
3223       JavaThread* thread = JavaThread::current();
3224       ThreadToNativeFromVM ttn(thread);
3225       HandleMark hm(thread);
3226       (*unload_entry)(&main_vm);
3227     }
3228   }
3229 }
3230 
3231 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3232 // Invokes JVM_OnLoad
3233 void Threads::create_vm_init_libraries() {
3234   extern struct JavaVM_ main_vm;
3235   AgentLibrary* agent;
3236 
3237   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3238     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3239 
3240     if (on_load_entry != NULL) {
3241       // Invoke the JVM_OnLoad function
3242       JavaThread* thread = JavaThread::current();
3243       ThreadToNativeFromVM ttn(thread);
3244       HandleMark hm(thread);
3245       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3246       if (err != JNI_OK) {
3247         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3248       }
3249     } else {
3250       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3251     }
3252   }
3253 }
3254 
3255 
3256 // Last thread running calls java.lang.Shutdown.shutdown()
3257 void JavaThread::invoke_shutdown_hooks() {
3258   HandleMark hm(this);
3259 
3260   // We could get here with a pending exception, if so clear it now or
3261   // it will cause MetaspaceShared::link_shared_classes to
3262   // fail for dynamic dump.
3263   if (this->has_pending_exception()) {
3264     this->clear_pending_exception();
3265   }
3266 
3267 #if INCLUDE_CDS
3268   // Link all classes for dynamic CDS dumping before vm exit.
3269   // Same operation is being done in JVM_BeforeHalt for handling the
3270   // case where the application calls System.exit().
3271   if (DynamicDumpSharedSpaces) {
3272     DynamicArchive::prepare_for_dynamic_dumping();
3273   }
3274 #endif
3275 
3276   EXCEPTION_MARK;
3277   Klass* shutdown_klass =
3278     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3279                                       THREAD);
3280   if (shutdown_klass != NULL) {
3281     // SystemDictionary::resolve_or_null will return null if there was
3282     // an exception.  If we cannot load the Shutdown class, just don't
3283     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3284     // won't be run.  Note that if a shutdown hook was registered,
3285     // the Shutdown class would have already been loaded
3286     // (Runtime.addShutdownHook will load it).
3287     JavaValue result(T_VOID);
3288     JavaCalls::call_static(&result,
3289                            shutdown_klass,
3290                            vmSymbols::shutdown_name(),
3291                            vmSymbols::void_method_signature(),
3292                            THREAD);
3293   }
3294   CLEAR_PENDING_EXCEPTION;
3295 }
3296 
3297 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3298 // the program falls off the end of main(). Another VM exit path is through
3299 // vm_exit() when the program calls System.exit() to return a value or when
3300 // there is a serious error in VM. The two shutdown paths are not exactly
3301 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3302 // and VM_Exit op at VM level.
3303 //
3304 // Shutdown sequence:
3305 //   + Shutdown native memory tracking if it is on
3306 //   + Wait until we are the last non-daemon thread to execute
3307 //     <-- every thing is still working at this moment -->
3308 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3309 //        shutdown hooks
3310 //   + Call before_exit(), prepare for VM exit
3311 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3312 //        currently the only user of this mechanism is File.deleteOnExit())
3313 //      > stop StatSampler, watcher thread,
3314 //        post thread end and vm death events to JVMTI,
3315 //        stop signal thread
3316 //   + Call JavaThread::exit(), it will:
3317 //      > release JNI handle blocks, remove stack guard pages
3318 //      > remove this thread from Threads list
3319 //     <-- no more Java code from this thread after this point -->
3320 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3321 //     the compiler threads at safepoint
3322 //     <-- do not use anything that could get blocked by Safepoint -->
3323 //   + Disable tracing at JNI/JVM barriers
3324 //   + Set _vm_exited flag for threads that are still running native code
3325 //   + Call exit_globals()
3326 //      > deletes tty
3327 //      > deletes PerfMemory resources
3328 //   + Delete this thread
3329 //   + Return to caller
3330 
3331 void Threads::destroy_vm() {
3332   JavaThread* thread = JavaThread::current();
3333 
3334 #ifdef ASSERT
3335   _vm_complete = false;
3336 #endif
3337   // Wait until we are the last non-daemon thread to execute
3338   {
3339     MonitorLocker nu(Threads_lock);
3340     while (Threads::number_of_non_daemon_threads() > 1)
3341       // This wait should make safepoint checks, wait without a timeout.
3342       nu.wait(0);
3343   }
3344 
3345   EventShutdown e;
3346   if (e.should_commit()) {
3347     e.set_reason("No remaining non-daemon Java threads");
3348     e.commit();
3349   }
3350 
3351   // Hang forever on exit if we are reporting an error.
3352   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
3353     os::infinite_sleep();
3354   }
3355   os::wait_for_keypress_at_exit();
3356 
3357   // run Java level shutdown hooks
3358   thread->invoke_shutdown_hooks();
3359 
3360   before_exit(thread);
3361 
3362   thread->exit(true);
3363 
3364   // We are no longer on the main thread list but could still be in a
3365   // secondary list where another thread may try to interact with us.
3366   // So wait until all such interactions are complete before we bring
3367   // the VM to the termination safepoint. Normally this would be done
3368   // using thread->smr_delete() below where we delete the thread, but
3369   // we can't call that after the termination safepoint is active as
3370   // we will deadlock on the Threads_lock. Once all interactions are
3371   // complete it is safe to directly delete the thread at any time.
3372   ThreadsSMRSupport::wait_until_not_protected(thread);
3373 
3374   // Stop VM thread.
3375   {
3376     // 4945125 The vm thread comes to a safepoint during exit.
3377     // GC vm_operations can get caught at the safepoint, and the
3378     // heap is unparseable if they are caught. Grab the Heap_lock
3379     // to prevent this. The GC vm_operations will not be able to
3380     // queue until after the vm thread is dead. After this point,
3381     // we'll never emerge out of the safepoint before the VM exits.
3382     // Assert that the thread is terminated so that acquiring the
3383     // Heap_lock doesn't cause the terminated thread to participate in
3384     // the safepoint protocol.
3385 
3386     assert(thread->is_terminated(), "must be terminated here");
3387     MutexLocker ml(Heap_lock);
3388 
3389     VMThread::wait_for_vm_thread_exit();
3390     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3391     VMThread::destroy();
3392   }
3393 
3394   // Now, all Java threads are gone except daemon threads. Daemon threads
3395   // running Java code or in VM are stopped by the Safepoint. However,
3396   // daemon threads executing native code are still running.  But they
3397   // will be stopped at native=>Java/VM barriers. Note that we can't
3398   // simply kill or suspend them, as it is inherently deadlock-prone.
3399 
3400   VM_Exit::set_vm_exited();
3401 
3402   // Clean up ideal graph printers after the VMThread has started
3403   // the final safepoint which will block all the Compiler threads.
3404   // Note that this Thread has already logically exited so the
3405   // clean_up() function's use of a JavaThreadIteratorWithHandle
3406   // would be a problem except set_vm_exited() has remembered the
3407   // shutdown thread which is granted a policy exception.
3408 #if defined(COMPILER2) && !defined(PRODUCT)
3409   IdealGraphPrinter::clean_up();
3410 #endif
3411 
3412   notify_vm_shutdown();
3413 
3414   // exit_globals() will delete tty
3415   exit_globals();
3416 
3417   // Deleting the shutdown thread here is safe. See comment on
3418   // wait_until_not_protected() above.
3419   delete thread;
3420 
3421 #if INCLUDE_JVMCI
3422   if (JVMCICounterSize > 0) {
3423     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
3424   }
3425 #endif
3426 
3427   LogConfiguration::finalize();
3428 }
3429 
3430 
3431 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3432   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3433   return is_supported_jni_version(version);
3434 }
3435 
3436 
3437 jboolean Threads::is_supported_jni_version(jint version) {
3438   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3439   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3440   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3441   if (version == JNI_VERSION_1_8) return JNI_TRUE;
3442   if (version == JNI_VERSION_9) return JNI_TRUE;
3443   if (version == JNI_VERSION_10) return JNI_TRUE;
3444   return JNI_FALSE;
3445 }
3446 
3447 
3448 void Threads::add(JavaThread* p, bool force_daemon) {
3449   // The threads lock must be owned at this point
3450   assert(Threads_lock->owned_by_self(), "must have threads lock");
3451 
3452   BarrierSet::barrier_set()->on_thread_attach(p);
3453 
3454   // Once a JavaThread is added to the Threads list, smr_delete() has
3455   // to be used to delete it. Otherwise we can just delete it directly.
3456   p->set_on_thread_list();
3457 
3458   _number_of_threads++;
3459   oop threadObj = p->threadObj();
3460   bool daemon = true;
3461   // Bootstrapping problem: threadObj can be null for initial
3462   // JavaThread (or for threads attached via JNI)
3463   if ((!force_daemon) && !is_daemon((threadObj))) {
3464     _number_of_non_daemon_threads++;
3465     daemon = false;
3466   }
3467 
3468   ThreadService::add_thread(p, daemon);
3469 
3470   // Maintain fast thread list
3471   ThreadsSMRSupport::add_thread(p);
3472 
3473   // Increase the ObjectMonitor ceiling for the new thread.
3474   ObjectSynchronizer::inc_in_use_list_ceiling();
3475 
3476   // Possible GC point.
3477   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
3478 
3479   // Make new thread known to active EscapeBarrier
3480   EscapeBarrier::thread_added(p);
3481 }
3482 
3483 void Threads::remove(JavaThread* p, bool is_daemon) {
3484   // Extra scope needed for Thread_lock, so we can check
3485   // that we do not remove thread without safepoint code notice
3486   { MonitorLocker ml(Threads_lock);
3487 
3488     // BarrierSet state must be destroyed after the last thread transition
3489     // before the thread terminates. Thread transitions result in calls to
3490     // StackWatermarkSet::on_safepoint(), which performs GC processing,
3491     // requiring the GC state to be alive.
3492     BarrierSet::barrier_set()->on_thread_detach(p);
3493 
3494     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
3495 
3496     // Maintain fast thread list
3497     ThreadsSMRSupport::remove_thread(p);
3498 
3499     _number_of_threads--;
3500     if (!is_daemon) {
3501       _number_of_non_daemon_threads--;
3502 
3503       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3504       // on destroy_vm will wake up.
3505       if (number_of_non_daemon_threads() == 1) {
3506         ml.notify_all();
3507       }
3508     }
3509     ThreadService::remove_thread(p, is_daemon);
3510 
3511     // Make sure that safepoint code disregard this thread. This is needed since
3512     // the thread might mess around with locks after this point. This can cause it
3513     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3514     // of this thread since it is removed from the queue.
3515     p->set_terminated(JavaThread::_thread_terminated);
3516 
3517     // Notify threads waiting in EscapeBarriers
3518     EscapeBarrier::thread_removed(p);
3519   } // unlock Threads_lock
3520 
3521   // Reduce the ObjectMonitor ceiling for the exiting thread.
3522   ObjectSynchronizer::dec_in_use_list_ceiling();
3523 
3524   // Since Events::log uses a lock, we grab it outside the Threads_lock
3525   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
3526 }
3527 
3528 // Operations on the Threads list for GC.  These are not explicitly locked,
3529 // but the garbage collector must provide a safe context for them to run.
3530 // In particular, these things should never be called when the Threads_lock
3531 // is held by some other thread. (Note: the Safepoint abstraction also
3532 // uses the Threads_lock to guarantee this property. It also makes sure that
3533 // all threads gets blocked when exiting or starting).
3534 
3535 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3536   ALL_JAVA_THREADS(p) {
3537     p->oops_do(f, cf);
3538   }
3539   VMThread::vm_thread()->oops_do(f, cf);
3540 }
3541 
3542 void Threads::change_thread_claim_token() {
3543   if (++_thread_claim_token == 0) {
3544     // On overflow of the token counter, there is a risk of future
3545     // collisions between a new global token value and a stale token
3546     // for a thread, because not all iterations visit all threads.
3547     // (Though it's pretty much a theoretical concern for non-trivial
3548     // token counter sizes.)  To deal with the possibility, reset all
3549     // the thread tokens to zero on global token overflow.
3550     struct ResetClaims : public ThreadClosure {
3551       virtual void do_thread(Thread* t) {
3552         t->claim_threads_do(false, 0);
3553       }
3554     } reset_claims;
3555     Threads::threads_do(&reset_claims);
3556     // On overflow, update the global token to non-zero, to
3557     // avoid the special "never claimed" initial thread value.
3558     _thread_claim_token = 1;
3559   }
3560 }
3561 
3562 #ifdef ASSERT
3563 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) {
3564   const uintx token = t->threads_do_token();
3565   assert(token == expected,
3566          "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != "
3567          UINTX_FORMAT, kind, p2i(t), token, expected);
3568 }
3569 
3570 void Threads::assert_all_threads_claimed() {
3571   ALL_JAVA_THREADS(p) {
3572     assert_thread_claimed("Thread", p, _thread_claim_token);
3573   }
3574   assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token);
3575 }
3576 #endif // ASSERT
3577 
3578 class ParallelOopsDoThreadClosure : public ThreadClosure {
3579 private:
3580   OopClosure* _f;
3581   CodeBlobClosure* _cf;
3582 public:
3583   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
3584   void do_thread(Thread* t) {
3585     t->oops_do(_f, _cf);
3586   }
3587 };
3588 
3589 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
3590   ParallelOopsDoThreadClosure tc(f, cf);
3591   possibly_parallel_threads_do(is_par, &tc);
3592 }
3593 
3594 void Threads::metadata_do(MetadataClosure* f) {
3595   ALL_JAVA_THREADS(p) {
3596     p->metadata_do(f);
3597   }
3598 }
3599 
3600 class ThreadHandlesClosure : public ThreadClosure {
3601   void (*_f)(Metadata*);
3602  public:
3603   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
3604   virtual void do_thread(Thread* thread) {
3605     thread->metadata_handles_do(_f);
3606   }
3607 };
3608 
3609 void Threads::metadata_handles_do(void f(Metadata*)) {
3610   // Only walk the Handles in Thread.
3611   ThreadHandlesClosure handles_closure(f);
3612   threads_do(&handles_closure);
3613 }
3614 
3615 // Get count Java threads that are waiting to enter the specified monitor.
3616 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
3617                                                          int count,
3618                                                          address monitor) {
3619   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3620 
3621   int i = 0;
3622   for (JavaThread* p : *t_list) {
3623     if (!p->can_call_java()) continue;
3624 
3625     // The first stage of async deflation does not affect any field
3626     // used by this comparison so the ObjectMonitor* is usable here.
3627     address pending = (address)p->current_pending_monitor();
3628     if (pending == monitor) {             // found a match
3629       if (i < count) result->append(p);   // save the first count matches
3630       i++;
3631     }
3632   }
3633 
3634   return result;
3635 }
3636 
3637 
3638 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
3639                                                       address owner) {
3640   // NULL owner means not locked so we can skip the search
3641   if (owner == NULL) return NULL;
3642 
3643   for (JavaThread* p : *t_list) {
3644     // first, see if owner is the address of a Java thread
3645     if (owner == (address)p) return p;
3646   }
3647 
3648   // Cannot assert on lack of success here since this function may be
3649   // used by code that is trying to report useful problem information
3650   // like deadlock detection.
3651   if (UseHeavyMonitors) return NULL;
3652 
3653   // If we didn't find a matching Java thread and we didn't force use of
3654   // heavyweight monitors, then the owner is the stack address of the
3655   // Lock Word in the owning Java thread's stack.
3656   //
3657   JavaThread* the_owner = NULL;
3658   for (JavaThread* q : *t_list) {
3659     if (q->is_lock_owned(owner)) {
3660       the_owner = q;
3661       break;
3662     }
3663   }
3664 
3665   // cannot assert on lack of success here; see above comment
3666   return the_owner;
3667 }
3668 
3669 class PrintOnClosure : public ThreadClosure {
3670 private:
3671   outputStream* _st;
3672 
3673 public:
3674   PrintOnClosure(outputStream* st) :
3675       _st(st) {}
3676 
3677   virtual void do_thread(Thread* thread) {
3678     if (thread != NULL) {
3679       thread->print_on(_st);
3680       _st->cr();
3681     }
3682   }
3683 };
3684 
3685 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3686 void Threads::print_on(outputStream* st, bool print_stacks,
3687                        bool internal_format, bool print_concurrent_locks,
3688                        bool print_extended_info) {
3689   char buf[32];
3690   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
3691 
3692   st->print_cr("Full thread dump %s (%s %s):",
3693                VM_Version::vm_name(),
3694                VM_Version::vm_release(),
3695                VM_Version::vm_info_string());
3696   st->cr();
3697 
3698 #if INCLUDE_SERVICES
3699   // Dump concurrent locks
3700   ConcurrentLocksDump concurrent_locks;
3701   if (print_concurrent_locks) {
3702     concurrent_locks.dump_at_safepoint();
3703   }
3704 #endif // INCLUDE_SERVICES
3705 
3706   ThreadsSMRSupport::print_info_on(st);
3707   st->cr();
3708 
3709   ALL_JAVA_THREADS(p) {
3710     ResourceMark rm;
3711     p->print_on(st, print_extended_info);
3712     if (print_stacks) {
3713       if (internal_format) {
3714         p->trace_stack();
3715       } else {
3716         p->print_stack_on(st);
3717       }
3718     }
3719     st->cr();
3720 #if INCLUDE_SERVICES
3721     if (print_concurrent_locks) {
3722       concurrent_locks.print_locks_on(p, st);
3723     }
3724 #endif // INCLUDE_SERVICES
3725   }
3726 
3727   PrintOnClosure cl(st);
3728   cl.do_thread(VMThread::vm_thread());
3729   Universe::heap()->gc_threads_do(&cl);
3730   if (StringDedup::is_enabled()) {
3731     StringDedup::threads_do(&cl);
3732   }
3733   cl.do_thread(WatcherThread::watcher_thread());
3734   cl.do_thread(AsyncLogWriter::instance());
3735 
3736   st->flush();
3737 }
3738 
3739 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
3740                              int buflen, bool* found_current) {
3741   if (this_thread != NULL) {
3742     bool is_current = (current == this_thread);
3743     *found_current = *found_current || is_current;
3744     st->print("%s", is_current ? "=>" : "  ");
3745 
3746     st->print(PTR_FORMAT, p2i(this_thread));
3747     st->print(" ");
3748     this_thread->print_on_error(st, buf, buflen);
3749     st->cr();
3750   }
3751 }
3752 
3753 class PrintOnErrorClosure : public ThreadClosure {
3754   outputStream* _st;
3755   Thread* _current;
3756   char* _buf;
3757   int _buflen;
3758   bool* _found_current;
3759  public:
3760   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
3761                       int buflen, bool* found_current) :
3762    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
3763 
3764   virtual void do_thread(Thread* thread) {
3765     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
3766   }
3767 };
3768 
3769 // Threads::print_on_error() is called by fatal error handler. It's possible
3770 // that VM is not at safepoint and/or current thread is inside signal handler.
3771 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3772 // memory (even in resource area), it might deadlock the error handler.
3773 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
3774                              int buflen) {
3775   ThreadsSMRSupport::print_info_on(st);
3776   st->cr();
3777 
3778   bool found_current = false;
3779   st->print_cr("Java Threads: ( => current thread )");
3780   ALL_JAVA_THREADS(thread) {
3781     print_on_error(thread, st, current, buf, buflen, &found_current);
3782   }
3783   st->cr();
3784 
3785   st->print_cr("Other Threads:");
3786   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
3787   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
3788   print_on_error(AsyncLogWriter::instance(), st, current, buf, buflen, &found_current);
3789 
3790   if (Universe::heap() != NULL) {
3791     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3792     Universe::heap()->gc_threads_do(&print_closure);
3793   }
3794 
3795   if (StringDedup::is_enabled()) {
3796     PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
3797     StringDedup::threads_do(&print_closure);
3798   }
3799 
3800   if (!found_current) {
3801     st->cr();
3802     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
3803     current->print_on_error(st, buf, buflen);
3804     st->cr();
3805   }
3806   st->cr();
3807 
3808   st->print_cr("Threads with active compile tasks:");
3809   print_threads_compiling(st, buf, buflen);
3810 }
3811 
3812 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) {
3813   ALL_JAVA_THREADS(thread) {
3814     if (thread->is_Compiler_thread()) {
3815       CompilerThread* ct = (CompilerThread*) thread;
3816 
3817       // Keep task in local variable for NULL check.
3818       // ct->_task might be set to NULL by concurring compiler thread
3819       // because it completed the compilation. The task is never freed,
3820       // though, just returned to a free list.
3821       CompileTask* task = ct->task();
3822       if (task != NULL) {
3823         thread->print_name_on_error(st, buf, buflen);
3824         st->print("  ");
3825         task->print(st, NULL, short_form, true);
3826       }
3827     }
3828   }
3829 }
3830 
3831 
3832 // Ad-hoc mutual exclusion primitives: SpinLock
3833 //
3834 // We employ SpinLocks _only for low-contention, fixed-length
3835 // short-duration critical sections where we're concerned
3836 // about native mutex_t or HotSpot Mutex:: latency.
3837 //
3838 // TODO-FIXME: ListLock should be of type SpinLock.
3839 // We should make this a 1st-class type, integrated into the lock
3840 // hierarchy as leaf-locks.  Critically, the SpinLock structure
3841 // should have sufficient padding to avoid false-sharing and excessive
3842 // cache-coherency traffic.
3843 
3844 
3845 typedef volatile int SpinLockT;
3846 
3847 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
3848   if (Atomic::cmpxchg(adr, 0, 1) == 0) {
3849     return;   // normal fast-path return
3850   }
3851 
3852   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
3853   int ctr = 0;
3854   int Yields = 0;
3855   for (;;) {
3856     while (*adr != 0) {
3857       ++ctr;
3858       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
3859         if (Yields > 5) {
3860           os::naked_short_sleep(1);
3861         } else {
3862           os::naked_yield();
3863           ++Yields;
3864         }
3865       } else {
3866         SpinPause();
3867       }
3868     }
3869     if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
3870   }
3871 }
3872 
3873 void Thread::SpinRelease(volatile int * adr) {
3874   assert(*adr != 0, "invariant");
3875   OrderAccess::fence();      // guarantee at least release consistency.
3876   // Roach-motel semantics.
3877   // It's safe if subsequent LDs and STs float "up" into the critical section,
3878   // but prior LDs and STs within the critical section can't be allowed
3879   // to reorder or float past the ST that releases the lock.
3880   // Loads and stores in the critical section - which appear in program
3881   // order before the store that releases the lock - must also appear
3882   // before the store that releases the lock in memory visibility order.
3883   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
3884   // the ST of 0 into the lock-word which releases the lock, so fence
3885   // more than covers this on all platforms.
3886   *adr = 0;
3887 }
3888 
3889 
3890 void Threads::verify() {
3891   ALL_JAVA_THREADS(p) {
3892     p->verify();
3893   }
3894   VMThread* thread = VMThread::vm_thread();
3895   if (thread != NULL) thread->verify();
3896 }
3897 
3898 #ifndef PRODUCT
3899 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
3900    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
3901 }
3902 #endif
3903 
3904 // Helper function to create the java.lang.Thread object for a
3905 // VM-internal thread. The thread will have the given name, be
3906 // part of the System ThreadGroup and if is_visible is true will be
3907 // discoverable via the system ThreadGroup.
3908 Handle JavaThread::create_system_thread_object(const char* name,
3909                                                bool is_visible, TRAPS) {
3910   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
3911 
3912   // Initialize thread_oop to put it into the system threadGroup.
3913   // This is done by calling the Thread(ThreadGroup tg, String name)
3914   // constructor, which adds the new thread to the group as an unstarted
3915   // thread.
3916   Handle thread_group(THREAD, Universe::system_thread_group());
3917   Handle thread_oop =
3918     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
3919                                       vmSymbols::threadgroup_string_void_signature(),
3920                                       thread_group,
3921                                       string,
3922                                       CHECK_NH);
3923 
3924   // If the Thread is intended to be visible then we have to mimic what
3925   // Thread.start() would do, by adding it to its ThreadGroup: tg.add(t).
3926   if (is_visible) {
3927     Klass* group = vmClasses::ThreadGroup_klass();
3928     JavaValue result(T_VOID);
3929     JavaCalls::call_special(&result,
3930                             thread_group,
3931                             group,
3932                             vmSymbols::add_method_name(),
3933                             vmSymbols::thread_void_signature(),
3934                             thread_oop,
3935                             CHECK_NH);
3936   }
3937 
3938   return thread_oop;
3939 }
3940 
3941 // Starts the target JavaThread as a daemon of the given priority, and
3942 // bound to the given java.lang.Thread instance.
3943 // The Threads_lock is held for the duration.
3944 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
3945                                        Handle thread_oop, ThreadPriority prio) {
3946 
3947   assert(target->osthread() != NULL, "target thread is not properly initialized");
3948 
3949   MutexLocker mu(current, Threads_lock);
3950 
3951   // Initialize the fields of the thread_oop first.
3952 
3953   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
3954 
3955   if (prio != NoPriority) {
3956     java_lang_Thread::set_priority(thread_oop(), prio);
3957     // Note: we don't call os::set_priority here. Possibly we should,
3958     // else all threads should call it themselves when they first run.
3959   }
3960 
3961   java_lang_Thread::set_daemon(thread_oop());
3962 
3963   // Now bind the thread_oop to the target JavaThread.
3964   target->set_threadObj(thread_oop());
3965 
3966   Threads::add(target); // target is now visible for safepoint/handshake
3967   Thread::start(target);
3968 }
3969 
3970 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
3971   // At this point it may be possible that no osthread was created for the
3972   // JavaThread due to lack of resources. However, since this must work
3973   // for critical system threads just check and abort if this fails.
3974   if (thread->osthread() == nullptr) {
3975     // This isn't really an OOM condition, but historically this is what
3976     // we report.
3977     vm_exit_during_initialization("java.lang.OutOfMemoryError",
3978                                   os::native_thread_creation_failed_msg());
3979   }
3980 }