1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "interpreter/interpreter.hpp"
  33 #include "interpreter/linkResolver.hpp"
  34 #include "interpreter/oopMapCache.hpp"
  35 #include "jfr/jfrEvents.hpp"
  36 #include "jvmtifiles/jvmtiEnv.hpp"
  37 #include "memory/gcLocker.inline.hpp"
  38 #include "memory/metaspaceShared.hpp"
  39 #include "memory/oopFactory.hpp"
  40 #include "memory/universe.inline.hpp"
  41 #include "oops/instanceKlass.hpp"
  42 #include "oops/objArrayOop.hpp"
  43 #include "oops/oop.inline.hpp"
  44 #include "oops/symbol.hpp"
  45 #include "prims/jvm_misc.hpp"
  46 #include "prims/jvmtiExport.hpp"
  47 #include "prims/jvmtiThreadState.hpp"
  48 #include "prims/privilegedStack.hpp"
  49 #include "runtime/arguments.hpp"
  50 #include "runtime/biasedLocking.hpp"
  51 #include "runtime/deoptimization.hpp"
  52 #include "runtime/fprofiler.hpp"
  53 #include "runtime/frame.inline.hpp"
  54 #include "runtime/init.hpp"
  55 #include "runtime/interfaceSupport.hpp"
  56 #include "runtime/java.hpp"
  57 #include "runtime/javaCalls.hpp"
  58 #include "runtime/jniPeriodicChecker.hpp"
  59 #include "runtime/memprofiler.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/objectMonitor.hpp"
  62 #include "runtime/orderAccess.inline.hpp"
  63 #include "runtime/osThread.hpp"
  64 #include "runtime/safepoint.hpp"
  65 #include "runtime/sharedRuntime.hpp"
  66 #include "runtime/statSampler.hpp"
  67 #include "runtime/stubRoutines.hpp"
  68 #include "runtime/task.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "runtime/threadCritical.hpp"
  71 #include "runtime/threadLocalStorage.hpp"
  72 #include "runtime/vframe.hpp"
  73 #include "runtime/vframeArray.hpp"
  74 #include "runtime/vframe_hp.hpp"
  75 #include "runtime/vmThread.hpp"
  76 #include "runtime/vm_operations.hpp"
  77 #include "services/attachListener.hpp"
  78 #include "services/management.hpp"
  79 #include "services/memTracker.hpp"
  80 #include "services/threadService.hpp"
  81 #include "utilities/defaultStream.hpp"
  82 #include "utilities/dtrace.hpp"
  83 #include "utilities/events.hpp"
  84 #include "utilities/preserveException.hpp"
  85 #include "utilities/macros.hpp"
  86 #ifdef TARGET_OS_FAMILY_linux
  87 # include "os_linux.inline.hpp"
  88 #endif
  89 #ifdef TARGET_OS_FAMILY_solaris
  90 # include "os_solaris.inline.hpp"
  91 #endif
  92 #ifdef TARGET_OS_FAMILY_windows
  93 # include "os_windows.inline.hpp"
  94 #endif
  95 #ifdef TARGET_OS_FAMILY_bsd
  96 # include "os_bsd.inline.hpp"
  97 #endif
  98 #if INCLUDE_ALL_GCS
  99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
 102 #endif // INCLUDE_ALL_GCS
 103 #ifdef COMPILER1
 104 #include "c1/c1_Compiler.hpp"
 105 #endif
 106 #ifdef COMPILER2
 107 #include "opto/c2compiler.hpp"
 108 #include "opto/idealGraphPrinter.hpp"
 109 #endif
 110 #if INCLUDE_RTM_OPT
 111 #include "runtime/rtmLocking.hpp"
 112 #endif
 113 #if INCLUDE_JFR
 114 #include "jfr/jfr.hpp"
 115 #endif
 116 
 117 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 118 
 119 #ifdef DTRACE_ENABLED
 120 
 121 // Only bother with this argument setup if dtrace is available
 122 
 123 #ifndef USDT2
 124 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
 125 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
 126 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
 127   intptr_t, intptr_t, bool);
 128 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
 129   intptr_t, intptr_t, bool);
 130 
 131 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 132   {                                                                        \
 133     ResourceMark rm(this);                                                 \
 134     int len = 0;                                                           \
 135     const char* name = (javathread)->get_thread_name();                    \
 136     len = strlen(name);                                                    \
 137     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
 138       name, len,                                                           \
 139       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 140       (javathread)->osthread()->thread_id(),                               \
 141       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 142   }
 143 
 144 #else /* USDT2 */
 145 
 146 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 147 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 148 
 149 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 150   {                                                                        \
 151     ResourceMark rm(this);                                                 \
 152     int len = 0;                                                           \
 153     const char* name = (javathread)->get_thread_name();                    \
 154     len = strlen(name);                                                    \
 155     HOTSPOT_THREAD_PROBE_##probe(  /* probe = start, stop */               \
 156       (char *) name, len,                                                           \
 157       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 158       (uintptr_t) (javathread)->osthread()->thread_id(),                               \
 159       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 160   }
 161 
 162 #endif /* USDT2 */
 163 
 164 #else //  ndef DTRACE_ENABLED
 165 
 166 #define DTRACE_THREAD_PROBE(probe, javathread)
 167 
 168 #endif // ndef DTRACE_ENABLED
 169 
 170 
 171 // Class hierarchy
 172 // - Thread
 173 //   - VMThread
 174 //   - WatcherThread
 175 //   - ConcurrentMarkSweepThread
 176 //   - JavaThread
 177 //     - CompilerThread
 178 
 179 // ======= Thread ========
 180 // Support for forcing alignment of thread objects for biased locking
 181 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 182   if (UseBiasedLocking) {
 183     const int alignment = markOopDesc::biased_lock_alignment;
 184     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 185     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 186                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 187                                               AllocFailStrategy::RETURN_NULL);
 188     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
 189     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 190            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 191            "JavaThread alignment code overflowed allocated storage");
 192     if (TraceBiasedLocking) {
 193       if (aligned_addr != real_malloc_addr)
 194         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 195                       real_malloc_addr, aligned_addr);
 196     }
 197     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 198     return aligned_addr;
 199   } else {
 200     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 201                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 202   }
 203 }
 204 
 205 void Thread::operator delete(void* p) {
 206   if (UseBiasedLocking) {
 207     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
 208     FreeHeap(real_malloc_addr, mtThread);
 209   } else {
 210     FreeHeap(p, mtThread);
 211   }
 212 }
 213 
 214 
 215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 216 // JavaThread
 217 
 218 
 219 Thread::Thread() {
 220   // stack and get_thread
 221   set_stack_base(NULL);
 222   set_stack_size(0);
 223   set_self_raw_id(0);
 224   set_lgrp_id(-1);
 225 
 226   // allocated data structures
 227   set_osthread(NULL);
 228   set_resource_area(new (mtThread)ResourceArea());
 229   DEBUG_ONLY(_current_resource_mark = NULL;)
 230   set_handle_area(new (mtThread) HandleArea(NULL));
 231   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 232   set_active_handles(NULL);
 233   set_free_handle_block(NULL);
 234   set_last_handle_mark(NULL);
 235 
 236   // This initial value ==> never claimed.
 237   _oops_do_parity = 0;
 238 
 239   _metadata_on_stack_buffer = NULL;
 240 
 241   // the handle mark links itself to last_handle_mark
 242   new HandleMark(this);
 243 
 244   // plain initialization
 245   debug_only(_owned_locks = NULL;)
 246   debug_only(_allow_allocation_count = 0;)
 247   NOT_PRODUCT(_allow_safepoint_count = 0;)
 248   NOT_PRODUCT(_skip_gcalot = false;)
 249   _jvmti_env_iteration_count = 0;
 250   set_allocated_bytes(0);
 251   _vm_operation_started_count = 0;
 252   _vm_operation_completed_count = 0;
 253   _current_pending_monitor = NULL;
 254   _current_pending_monitor_is_from_java = true;
 255   _current_waiting_monitor = NULL;
 256   _num_nested_signal = 0;
 257   omFreeList = NULL ;
 258   omFreeCount = 0 ;
 259   omFreeProvision = 32 ;
 260   omInUseList = NULL ;
 261   omInUseCount = 0 ;
 262 
 263 #ifdef ASSERT
 264   _visited_for_critical_count = false;
 265 #endif
 266 
 267   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
 268   _suspend_flags = 0;
 269 
 270   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 271   _hashStateX = os::random() ;
 272   _hashStateY = 842502087 ;
 273   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
 274   _hashStateW = 273326509 ;
 275 
 276   _OnTrap   = 0 ;
 277   _schedctl = NULL ;
 278   _Stalled  = 0 ;
 279   _TypeTag  = 0x2BAD ;
 280 
 281   // Many of the following fields are effectively final - immutable
 282   // Note that nascent threads can't use the Native Monitor-Mutex
 283   // construct until the _MutexEvent is initialized ...
 284   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 285   // we might instead use a stack of ParkEvents that we could provision on-demand.
 286   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 287   // and ::Release()
 288   _ParkEvent   = ParkEvent::Allocate (this) ;
 289   _SleepEvent  = ParkEvent::Allocate (this) ;
 290   _MutexEvent  = ParkEvent::Allocate (this) ;
 291   _MuxEvent    = ParkEvent::Allocate (this) ;
 292 
 293 #ifdef CHECK_UNHANDLED_OOPS
 294   if (CheckUnhandledOops) {
 295     _unhandled_oops = new UnhandledOops(this);
 296   }
 297 #endif // CHECK_UNHANDLED_OOPS
 298 #ifdef ASSERT
 299   if (UseBiasedLocking) {
 300     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 301     assert(this == _real_malloc_address ||
 302            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 303            "bug in forced alignment of thread objects");
 304   }
 305 #endif /* ASSERT */
 306 }
 307 
 308 void Thread::initialize_thread_local_storage() {
 309   // Note: Make sure this method only calls
 310   // non-blocking operations. Otherwise, it might not work
 311   // with the thread-startup/safepoint interaction.
 312 
 313   // During Java thread startup, safepoint code should allow this
 314   // method to complete because it may need to allocate memory to
 315   // store information for the new thread.
 316 
 317   // initialize structure dependent on thread local storage
 318   ThreadLocalStorage::set_thread(this);
 319 }
 320 
 321 void Thread::record_stack_base_and_size() {
 322   set_stack_base(os::current_stack_base());
 323   set_stack_size(os::current_stack_size());
 324   if (is_Java_thread()) {
 325     ((JavaThread*) this)->set_stack_overflow_limit();
 326   }
 327   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 328   // in initialize_thread(). Without the adjustment, stack size is
 329   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 330   // So far, only Solaris has real implementation of initialize_thread().
 331   //
 332   // set up any platform-specific state.
 333   os::initialize_thread(this);
 334 
 335 #if INCLUDE_NMT
 336   // record thread's native stack, stack grows downward
 337   address stack_low_addr = stack_base() - stack_size();
 338   MemTracker::record_thread_stack(stack_low_addr, stack_size());
 339 #endif // INCLUDE_NMT
 340 }
 341 
 342 
 343 Thread::~Thread() {
 344   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 345   ObjectSynchronizer::omFlush (this) ;
 346 
 347   // stack_base can be NULL if the thread is never started or exited before
 348   // record_stack_base_and_size called. Although, we would like to ensure
 349   // that all started threads do call record_stack_base_and_size(), there is
 350   // not proper way to enforce that.
 351 #if INCLUDE_NMT
 352   if (_stack_base != NULL) {
 353     address low_stack_addr = stack_base() - stack_size();
 354     MemTracker::release_thread_stack(low_stack_addr, stack_size());
 355 #ifdef ASSERT
 356     set_stack_base(NULL);
 357 #endif
 358   }
 359 #endif // INCLUDE_NMT
 360 
 361   // deallocate data structures
 362   delete resource_area();
 363   // since the handle marks are using the handle area, we have to deallocated the root
 364   // handle mark before deallocating the thread's handle area,
 365   assert(last_handle_mark() != NULL, "check we have an element");
 366   delete last_handle_mark();
 367   assert(last_handle_mark() == NULL, "check we have reached the end");
 368 
 369   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 370   // We NULL out the fields for good hygiene.
 371   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 372   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 373   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 374   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 375 
 376   delete handle_area();
 377   delete metadata_handles();
 378 
 379   // osthread() can be NULL, if creation of thread failed.
 380   if (osthread() != NULL) os::free_thread(osthread());
 381 
 382   delete _SR_lock;
 383 
 384   // clear thread local storage if the Thread is deleting itself
 385   if (this == Thread::current()) {
 386     ThreadLocalStorage::set_thread(NULL);
 387   } else {
 388     // In the case where we're not the current thread, invalidate all the
 389     // caches in case some code tries to get the current thread or the
 390     // thread that was destroyed, and gets stale information.
 391     ThreadLocalStorage::invalidate_all();
 392   }
 393   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 394 }
 395 
 396 // NOTE: dummy function for assertion purpose.
 397 void Thread::run() {
 398   ShouldNotReachHere();
 399 }
 400 
 401 #ifdef ASSERT
 402 // Private method to check for dangling thread pointer
 403 void check_for_dangling_thread_pointer(Thread *thread) {
 404  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 405          "possibility of dangling Thread pointer");
 406 }
 407 #endif
 408 
 409 
 410 #ifndef PRODUCT
 411 // Tracing method for basic thread operations
 412 void Thread::trace(const char* msg, const Thread* const thread) {
 413   if (!TraceThreadEvents) return;
 414   ResourceMark rm;
 415   ThreadCritical tc;
 416   const char *name = "non-Java thread";
 417   int prio = -1;
 418   if (thread->is_Java_thread()
 419       && !thread->is_Compiler_thread()) {
 420     // The Threads_lock must be held to get information about
 421     // this thread but may not be in some situations when
 422     // tracing  thread events.
 423     bool release_Threads_lock = false;
 424     if (!Threads_lock->owned_by_self()) {
 425       Threads_lock->lock();
 426       release_Threads_lock = true;
 427     }
 428     JavaThread* jt = (JavaThread *)thread;
 429     name = (char *)jt->get_thread_name();
 430     oop thread_oop = jt->threadObj();
 431     if (thread_oop != NULL) {
 432       prio = java_lang_Thread::priority(thread_oop);
 433     }
 434     if (release_Threads_lock) {
 435       Threads_lock->unlock();
 436     }
 437   }
 438   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 439 }
 440 #endif
 441 
 442 
 443 ThreadPriority Thread::get_priority(const Thread* const thread) {
 444   trace("get priority", thread);
 445   ThreadPriority priority;
 446   // Can return an error!
 447   (void)os::get_priority(thread, priority);
 448   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 449   return priority;
 450 }
 451 
 452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 453   trace("set priority", thread);
 454   debug_only(check_for_dangling_thread_pointer(thread);)
 455   // Can return an error!
 456   (void)os::set_priority(thread, priority);
 457 }
 458 
 459 
 460 void Thread::start(Thread* thread) {
 461   trace("start", thread);
 462   // Start is different from resume in that its safety is guaranteed by context or
 463   // being called from a Java method synchronized on the Thread object.
 464   if (!DisableStartThread) {
 465     if (thread->is_Java_thread()) {
 466       // Initialize the thread state to RUNNABLE before starting this thread.
 467       // Can not set it after the thread started because we do not know the
 468       // exact thread state at that time. It could be in MONITOR_WAIT or
 469       // in SLEEPING or some other state.
 470       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 471                                           java_lang_Thread::RUNNABLE);
 472     }
 473     os::start_thread(thread);
 474   }
 475 }
 476 
 477 // Enqueue a VM_Operation to do the job for us - sometime later
 478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 479   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 480   VMThread::execute(vm_stop);
 481 }
 482 
 483 
 484 //
 485 // Check if an external suspend request has completed (or has been
 486 // cancelled). Returns true if the thread is externally suspended and
 487 // false otherwise.
 488 //
 489 // The bits parameter returns information about the code path through
 490 // the routine. Useful for debugging:
 491 //
 492 // set in is_ext_suspend_completed():
 493 // 0x00000001 - routine was entered
 494 // 0x00000010 - routine return false at end
 495 // 0x00000100 - thread exited (return false)
 496 // 0x00000200 - suspend request cancelled (return false)
 497 // 0x00000400 - thread suspended (return true)
 498 // 0x00001000 - thread is in a suspend equivalent state (return true)
 499 // 0x00002000 - thread is native and walkable (return true)
 500 // 0x00004000 - thread is native_trans and walkable (needed retry)
 501 //
 502 // set in wait_for_ext_suspend_completion():
 503 // 0x00010000 - routine was entered
 504 // 0x00020000 - suspend request cancelled before loop (return false)
 505 // 0x00040000 - thread suspended before loop (return true)
 506 // 0x00080000 - suspend request cancelled in loop (return false)
 507 // 0x00100000 - thread suspended in loop (return true)
 508 // 0x00200000 - suspend not completed during retry loop (return false)
 509 //
 510 
 511 // Helper class for tracing suspend wait debug bits.
 512 //
 513 // 0x00000100 indicates that the target thread exited before it could
 514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 515 // 0x00080000 each indicate a cancelled suspend request so they don't
 516 // count as wait failures either.
 517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 518 
 519 class TraceSuspendDebugBits : public StackObj {
 520  private:
 521   JavaThread * jt;
 522   bool         is_wait;
 523   bool         called_by_wait;  // meaningful when !is_wait
 524   uint32_t *   bits;
 525 
 526  public:
 527   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 528                         uint32_t *_bits) {
 529     jt             = _jt;
 530     is_wait        = _is_wait;
 531     called_by_wait = _called_by_wait;
 532     bits           = _bits;
 533   }
 534 
 535   ~TraceSuspendDebugBits() {
 536     if (!is_wait) {
 537 #if 1
 538       // By default, don't trace bits for is_ext_suspend_completed() calls.
 539       // That trace is very chatty.
 540       return;
 541 #else
 542       if (!called_by_wait) {
 543         // If tracing for is_ext_suspend_completed() is enabled, then only
 544         // trace calls to it from wait_for_ext_suspend_completion()
 545         return;
 546       }
 547 #endif
 548     }
 549 
 550     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 551       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 552         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 553         ResourceMark rm;
 554 
 555         tty->print_cr(
 556             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 557             jt->get_thread_name(), *bits);
 558 
 559         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 560       }
 561     }
 562   }
 563 };
 564 #undef DEBUG_FALSE_BITS
 565 
 566 
 567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 568   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 569 
 570   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 571   bool do_trans_retry;           // flag to force the retry
 572 
 573   *bits |= 0x00000001;
 574 
 575   do {
 576     do_trans_retry = false;
 577 
 578     if (is_exiting()) {
 579       // Thread is in the process of exiting. This is always checked
 580       // first to reduce the risk of dereferencing a freed JavaThread.
 581       *bits |= 0x00000100;
 582       return false;
 583     }
 584 
 585     if (!is_external_suspend()) {
 586       // Suspend request is cancelled. This is always checked before
 587       // is_ext_suspended() to reduce the risk of a rogue resume
 588       // confusing the thread that made the suspend request.
 589       *bits |= 0x00000200;
 590       return false;
 591     }
 592 
 593     if (is_ext_suspended()) {
 594       // thread is suspended
 595       *bits |= 0x00000400;
 596       return true;
 597     }
 598 
 599     // Now that we no longer do hard suspends of threads running
 600     // native code, the target thread can be changing thread state
 601     // while we are in this routine:
 602     //
 603     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 604     //
 605     // We save a copy of the thread state as observed at this moment
 606     // and make our decision about suspend completeness based on the
 607     // copy. This closes the race where the thread state is seen as
 608     // _thread_in_native_trans in the if-thread_blocked check, but is
 609     // seen as _thread_blocked in if-thread_in_native_trans check.
 610     JavaThreadState save_state = thread_state();
 611 
 612     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 613       // If the thread's state is _thread_blocked and this blocking
 614       // condition is known to be equivalent to a suspend, then we can
 615       // consider the thread to be externally suspended. This means that
 616       // the code that sets _thread_blocked has been modified to do
 617       // self-suspension if the blocking condition releases. We also
 618       // used to check for CONDVAR_WAIT here, but that is now covered by
 619       // the _thread_blocked with self-suspension check.
 620       //
 621       // Return true since we wouldn't be here unless there was still an
 622       // external suspend request.
 623       *bits |= 0x00001000;
 624       return true;
 625     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 626       // Threads running native code will self-suspend on native==>VM/Java
 627       // transitions. If its stack is walkable (should always be the case
 628       // unless this function is called before the actual java_suspend()
 629       // call), then the wait is done.
 630       *bits |= 0x00002000;
 631       return true;
 632     } else if (!called_by_wait && !did_trans_retry &&
 633                save_state == _thread_in_native_trans &&
 634                frame_anchor()->walkable()) {
 635       // The thread is transitioning from thread_in_native to another
 636       // thread state. check_safepoint_and_suspend_for_native_trans()
 637       // will force the thread to self-suspend. If it hasn't gotten
 638       // there yet we may have caught the thread in-between the native
 639       // code check above and the self-suspend. Lucky us. If we were
 640       // called by wait_for_ext_suspend_completion(), then it
 641       // will be doing the retries so we don't have to.
 642       //
 643       // Since we use the saved thread state in the if-statement above,
 644       // there is a chance that the thread has already transitioned to
 645       // _thread_blocked by the time we get here. In that case, we will
 646       // make a single unnecessary pass through the logic below. This
 647       // doesn't hurt anything since we still do the trans retry.
 648 
 649       *bits |= 0x00004000;
 650 
 651       // Once the thread leaves thread_in_native_trans for another
 652       // thread state, we break out of this retry loop. We shouldn't
 653       // need this flag to prevent us from getting back here, but
 654       // sometimes paranoia is good.
 655       did_trans_retry = true;
 656 
 657       // We wait for the thread to transition to a more usable state.
 658       for (int i = 1; i <= SuspendRetryCount; i++) {
 659         // We used to do an "os::yield_all(i)" call here with the intention
 660         // that yielding would increase on each retry. However, the parameter
 661         // is ignored on Linux which means the yield didn't scale up. Waiting
 662         // on the SR_lock below provides a much more predictable scale up for
 663         // the delay. It also provides a simple/direct point to check for any
 664         // safepoint requests from the VMThread
 665 
 666         // temporarily drops SR_lock while doing wait with safepoint check
 667         // (if we're a JavaThread - the WatcherThread can also call this)
 668         // and increase delay with each retry
 669         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 670 
 671         // check the actual thread state instead of what we saved above
 672         if (thread_state() != _thread_in_native_trans) {
 673           // the thread has transitioned to another thread state so
 674           // try all the checks (except this one) one more time.
 675           do_trans_retry = true;
 676           break;
 677         }
 678       } // end retry loop
 679 
 680 
 681     }
 682   } while (do_trans_retry);
 683 
 684   *bits |= 0x00000010;
 685   return false;
 686 }
 687 
 688 //
 689 // Wait for an external suspend request to complete (or be cancelled).
 690 // Returns true if the thread is externally suspended and false otherwise.
 691 //
 692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 693        uint32_t *bits) {
 694   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 695                              false /* !called_by_wait */, bits);
 696 
 697   // local flag copies to minimize SR_lock hold time
 698   bool is_suspended;
 699   bool pending;
 700   uint32_t reset_bits;
 701 
 702   // set a marker so is_ext_suspend_completed() knows we are the caller
 703   *bits |= 0x00010000;
 704 
 705   // We use reset_bits to reinitialize the bits value at the top of
 706   // each retry loop. This allows the caller to make use of any
 707   // unused bits for their own marking purposes.
 708   reset_bits = *bits;
 709 
 710   {
 711     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 712     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 713                                             delay, bits);
 714     pending = is_external_suspend();
 715   }
 716   // must release SR_lock to allow suspension to complete
 717 
 718   if (!pending) {
 719     // A cancelled suspend request is the only false return from
 720     // is_ext_suspend_completed() that keeps us from entering the
 721     // retry loop.
 722     *bits |= 0x00020000;
 723     return false;
 724   }
 725 
 726   if (is_suspended) {
 727     *bits |= 0x00040000;
 728     return true;
 729   }
 730 
 731   for (int i = 1; i <= retries; i++) {
 732     *bits = reset_bits;  // reinit to only track last retry
 733 
 734     // We used to do an "os::yield_all(i)" call here with the intention
 735     // that yielding would increase on each retry. However, the parameter
 736     // is ignored on Linux which means the yield didn't scale up. Waiting
 737     // on the SR_lock below provides a much more predictable scale up for
 738     // the delay. It also provides a simple/direct point to check for any
 739     // safepoint requests from the VMThread
 740 
 741     {
 742       MutexLocker ml(SR_lock());
 743       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 744       // can also call this)  and increase delay with each retry
 745       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 746 
 747       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 748                                               delay, bits);
 749 
 750       // It is possible for the external suspend request to be cancelled
 751       // (by a resume) before the actual suspend operation is completed.
 752       // Refresh our local copy to see if we still need to wait.
 753       pending = is_external_suspend();
 754     }
 755 
 756     if (!pending) {
 757       // A cancelled suspend request is the only false return from
 758       // is_ext_suspend_completed() that keeps us from staying in the
 759       // retry loop.
 760       *bits |= 0x00080000;
 761       return false;
 762     }
 763 
 764     if (is_suspended) {
 765       *bits |= 0x00100000;
 766       return true;
 767     }
 768   } // end retry loop
 769 
 770   // thread did not suspend after all our retries
 771   *bits |= 0x00200000;
 772   return false;
 773 }
 774 
 775 #ifndef PRODUCT
 776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 777 
 778   // This should not need to be atomic as the only way for simultaneous
 779   // updates is via interrupts. Even then this should be rare or non-existant
 780   // and we don't care that much anyway.
 781 
 782   int index = _jmp_ring_index;
 783   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 784   _jmp_ring[index]._target = (intptr_t) target;
 785   _jmp_ring[index]._instruction = (intptr_t) instr;
 786   _jmp_ring[index]._file = file;
 787   _jmp_ring[index]._line = line;
 788 }
 789 #endif /* PRODUCT */
 790 
 791 // Called by flat profiler
 792 // Callers have already called wait_for_ext_suspend_completion
 793 // The assertion for that is currently too complex to put here:
 794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 795   bool gotframe = false;
 796   // self suspension saves needed state.
 797   if (has_last_Java_frame() && _anchor.walkable()) {
 798      *_fr = pd_last_frame();
 799      gotframe = true;
 800   }
 801   return gotframe;
 802 }
 803 
 804 void Thread::interrupt(Thread* thread) {
 805   trace("interrupt", thread);
 806   debug_only(check_for_dangling_thread_pointer(thread);)
 807   os::interrupt(thread);
 808 }
 809 
 810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 811   trace("is_interrupted", thread);
 812   debug_only(check_for_dangling_thread_pointer(thread);)
 813   // Note:  If clear_interrupted==false, this simply fetches and
 814   // returns the value of the field osthread()->interrupted().
 815   return os::is_interrupted(thread, clear_interrupted);
 816 }
 817 
 818 
 819 // GC Support
 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 821   jint thread_parity = _oops_do_parity;
 822   if (thread_parity != strong_roots_parity) {
 823     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 824     if (res == thread_parity) {
 825       return true;
 826     } else {
 827       guarantee(res == strong_roots_parity, "Or else what?");
 828       assert(SharedHeap::heap()->workers()->active_workers() > 0,
 829          "Should only fail when parallel.");
 830       return false;
 831     }
 832   }
 833   assert(SharedHeap::heap()->workers()->active_workers() > 0,
 834          "Should only fail when parallel.");
 835   return false;
 836 }
 837 
 838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
 839   active_handles()->oops_do(f);
 840   // Do oop for ThreadShadow
 841   f->do_oop((oop*)&_pending_exception);
 842   handle_area()->oops_do(f);
 843 }
 844 
 845 void Thread::nmethods_do(CodeBlobClosure* cf) {
 846   // no nmethods in a generic thread...
 847 }
 848 
 849 void Thread::metadata_do(void f(Metadata*)) {
 850   if (metadata_handles() != NULL) {
 851     for (int i = 0; i< metadata_handles()->length(); i++) {
 852       f(metadata_handles()->at(i));
 853     }
 854   }
 855 }
 856 
 857 void Thread::print_on(outputStream* st) const {
 858   // get_priority assumes osthread initialized
 859   if (osthread() != NULL) {
 860     int os_prio;
 861     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 862       st->print("os_prio=%d ", os_prio);
 863     }
 864     st->print("tid=" INTPTR_FORMAT " ", this);
 865     ext().print_on(st);
 866     osthread()->print_on(st);
 867   }
 868   debug_only(if (WizardMode) print_owned_locks_on(st);)
 869 }
 870 
 871 // Thread::print_on_error() is called by fatal error handler. Don't use
 872 // any lock or allocate memory.
 873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 874   if      (is_VM_thread())                  st->print("VMThread");
 875   else if (is_Compiler_thread())            st->print("CompilerThread");
 876   else if (is_Java_thread())                st->print("JavaThread");
 877   else if (is_GC_task_thread())             st->print("GCTaskThread");
 878   else if (is_Watcher_thread())             st->print("WatcherThread");
 879   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 880   else st->print("Thread");
 881 
 882   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 883             _stack_base - _stack_size, _stack_base);
 884 
 885   if (osthread()) {
 886     st->print(" [id=%d]", osthread()->thread_id());
 887   }
 888 }
 889 
 890 #ifdef ASSERT
 891 void Thread::print_owned_locks_on(outputStream* st) const {
 892   Monitor *cur = _owned_locks;
 893   if (cur == NULL) {
 894     st->print(" (no locks) ");
 895   } else {
 896     st->print_cr(" Locks owned:");
 897     while(cur) {
 898       cur->print_on(st);
 899       cur = cur->next();
 900     }
 901   }
 902 }
 903 
 904 static int ref_use_count  = 0;
 905 
 906 bool Thread::owns_locks_but_compiled_lock() const {
 907   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 908     if (cur != Compile_lock) return true;
 909   }
 910   return false;
 911 }
 912 
 913 
 914 #endif
 915 
 916 #ifndef PRODUCT
 917 
 918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 920 // no threads which allow_vm_block's are held
 921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 922     // Check if current thread is allowed to block at a safepoint
 923     if (!(_allow_safepoint_count == 0))
 924       fatal("Possible safepoint reached by thread that does not allow it");
 925     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 926       fatal("LEAF method calling lock?");
 927     }
 928 
 929 #ifdef ASSERT
 930     if (potential_vm_operation && is_Java_thread()
 931         && !Universe::is_bootstrapping()) {
 932       // Make sure we do not hold any locks that the VM thread also uses.
 933       // This could potentially lead to deadlocks
 934       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 935         // Threads_lock is special, since the safepoint synchronization will not start before this is
 936         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 937         // since it is used to transfer control between JavaThreads and the VMThread
 938         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
 939         if ( (cur->allow_vm_block() &&
 940               cur != Threads_lock &&
 941               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
 942               cur != VMOperationRequest_lock &&
 943               cur != VMOperationQueue_lock) ||
 944               cur->rank() == Mutex::special) {
 945           fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
 946         }
 947       }
 948     }
 949 
 950     if (GCALotAtAllSafepoints) {
 951       // We could enter a safepoint here and thus have a gc
 952       InterfaceSupport::check_gc_alot();
 953     }
 954 #endif
 955 }
 956 #endif
 957 
 958 bool Thread::is_in_stack(address adr) const {
 959   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 960   address end = os::current_stack_pointer();
 961   // Allow non Java threads to call this without stack_base
 962   if (_stack_base == NULL) return true;
 963   if (stack_base() >= adr && adr >= end) return true;
 964 
 965   return false;
 966 }
 967 
 968 
 969 bool Thread::is_in_usable_stack(address adr) const {
 970   size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
 971   size_t usable_stack_size = _stack_size - stack_guard_size;
 972 
 973   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
 974 }
 975 
 976 
 977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 979 // used for compilation in the future. If that change is made, the need for these methods
 980 // should be revisited, and they should be removed if possible.
 981 
 982 bool Thread::is_lock_owned(address adr) const {
 983   return on_local_stack(adr);
 984 }
 985 
 986 bool Thread::set_as_starting_thread() {
 987  // NOTE: this must be called inside the main thread.
 988   return os::create_main_thread((JavaThread*)this);
 989 }
 990 
 991 static void initialize_class(Symbol* class_name, TRAPS) {
 992   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 993   InstanceKlass::cast(klass)->initialize(CHECK);
 994 }
 995 
 996 
 997 // Creates the initial ThreadGroup
 998 static Handle create_initial_thread_group(TRAPS) {
 999   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1000   instanceKlassHandle klass (THREAD, k);
1001 
1002   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1003   {
1004     JavaValue result(T_VOID);
1005     JavaCalls::call_special(&result,
1006                             system_instance,
1007                             klass,
1008                             vmSymbols::object_initializer_name(),
1009                             vmSymbols::void_method_signature(),
1010                             CHECK_NH);
1011   }
1012   Universe::set_system_thread_group(system_instance());
1013 
1014   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1015   {
1016     JavaValue result(T_VOID);
1017     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1018     JavaCalls::call_special(&result,
1019                             main_instance,
1020                             klass,
1021                             vmSymbols::object_initializer_name(),
1022                             vmSymbols::threadgroup_string_void_signature(),
1023                             system_instance,
1024                             string,
1025                             CHECK_NH);
1026   }
1027   return main_instance;
1028 }
1029 
1030 // Creates the initial Thread
1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1032   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1033   instanceKlassHandle klass (THREAD, k);
1034   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1035 
1036   java_lang_Thread::set_thread(thread_oop(), thread);
1037   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1038   thread->set_threadObj(thread_oop());
1039 
1040   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1041 
1042   JavaValue result(T_VOID);
1043   JavaCalls::call_special(&result, thread_oop,
1044                                    klass,
1045                                    vmSymbols::object_initializer_name(),
1046                                    vmSymbols::threadgroup_string_void_signature(),
1047                                    thread_group,
1048                                    string,
1049                                    CHECK_NULL);
1050   return thread_oop();
1051 }
1052 
1053 static void call_initializeSystemClass(TRAPS) {
1054   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1055   instanceKlassHandle klass (THREAD, k);
1056 
1057   JavaValue result(T_VOID);
1058   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1059                                          vmSymbols::void_method_signature(), CHECK);
1060 }
1061 
1062 char java_runtime_name[128] = "";
1063 char java_runtime_version[128] = "";
1064 
1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1066 static const char* get_java_runtime_name(TRAPS) {
1067   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069   fieldDescriptor fd;
1070   bool found = k != NULL &&
1071                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1072                                                         vmSymbols::string_signature(), &fd);
1073   if (found) {
1074     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075     if (name_oop == NULL)
1076       return NULL;
1077     const char* name = java_lang_String::as_utf8_string(name_oop,
1078                                                         java_runtime_name,
1079                                                         sizeof(java_runtime_name));
1080     return name;
1081   } else {
1082     return NULL;
1083   }
1084 }
1085 
1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1087 static const char* get_java_runtime_version(TRAPS) {
1088   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1089                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1090   fieldDescriptor fd;
1091   bool found = k != NULL &&
1092                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1093                                                         vmSymbols::string_signature(), &fd);
1094   if (found) {
1095     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1096     if (name_oop == NULL)
1097       return NULL;
1098     const char* name = java_lang_String::as_utf8_string(name_oop,
1099                                                         java_runtime_version,
1100                                                         sizeof(java_runtime_version));
1101     return name;
1102   } else {
1103     return NULL;
1104   }
1105 }
1106 
1107 // General purpose hook into Java code, run once when the VM is initialized.
1108 // The Java library method itself may be changed independently from the VM.
1109 static void call_postVMInitHook(TRAPS) {
1110   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1111   instanceKlassHandle klass (THREAD, k);
1112   if (klass.not_null()) {
1113     JavaValue result(T_VOID);
1114     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1115                                            vmSymbols::void_method_signature(),
1116                                            CHECK);
1117   }
1118 }
1119 
1120 static void reset_vm_info_property(TRAPS) {
1121   // the vm info string
1122   ResourceMark rm(THREAD);
1123   const char *vm_info = VM_Version::vm_info_string();
1124 
1125   // java.lang.System class
1126   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1127   instanceKlassHandle klass (THREAD, k);
1128 
1129   // setProperty arguments
1130   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1131   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1132 
1133   // return value
1134   JavaValue r(T_OBJECT);
1135 
1136   // public static String setProperty(String key, String value);
1137   JavaCalls::call_static(&r,
1138                          klass,
1139                          vmSymbols::setProperty_name(),
1140                          vmSymbols::string_string_string_signature(),
1141                          key_str,
1142                          value_str,
1143                          CHECK);
1144 }
1145 
1146 
1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1148   assert(thread_group.not_null(), "thread group should be specified");
1149   assert(threadObj() == NULL, "should only create Java thread object once");
1150 
1151   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1152   instanceKlassHandle klass (THREAD, k);
1153   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1154 
1155   java_lang_Thread::set_thread(thread_oop(), this);
1156   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1157   set_threadObj(thread_oop());
1158 
1159   JavaValue result(T_VOID);
1160   if (thread_name != NULL) {
1161     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1162     // Thread gets assigned specified name and null target
1163     JavaCalls::call_special(&result,
1164                             thread_oop,
1165                             klass,
1166                             vmSymbols::object_initializer_name(),
1167                             vmSymbols::threadgroup_string_void_signature(),
1168                             thread_group, // Argument 1
1169                             name,         // Argument 2
1170                             THREAD);
1171   } else {
1172     // Thread gets assigned name "Thread-nnn" and null target
1173     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1174     JavaCalls::call_special(&result,
1175                             thread_oop,
1176                             klass,
1177                             vmSymbols::object_initializer_name(),
1178                             vmSymbols::threadgroup_runnable_void_signature(),
1179                             thread_group, // Argument 1
1180                             Handle(),     // Argument 2
1181                             THREAD);
1182   }
1183 
1184 
1185   if (daemon) {
1186       java_lang_Thread::set_daemon(thread_oop());
1187   }
1188 
1189   if (HAS_PENDING_EXCEPTION) {
1190     return;
1191   }
1192 
1193   KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1194   Handle threadObj(this, this->threadObj());
1195 
1196   JavaCalls::call_special(&result,
1197                          thread_group,
1198                          group,
1199                          vmSymbols::add_method_name(),
1200                          vmSymbols::thread_void_signature(),
1201                          threadObj,          // Arg 1
1202                          THREAD);
1203 
1204 
1205 }
1206 
1207 // NamedThread --  non-JavaThread subclasses with multiple
1208 // uniquely named instances should derive from this.
1209 NamedThread::NamedThread() : Thread() {
1210   _name = NULL;
1211   _processed_thread = NULL;
1212 }
1213 
1214 NamedThread::~NamedThread() {
1215   JFR_ONLY(Jfr::on_thread_exit(this);)
1216   if (_name != NULL) {
1217     FREE_C_HEAP_ARRAY(char, _name, mtThread);
1218     _name = NULL;
1219   }
1220 }
1221 
1222 void NamedThread::set_name(const char* format, ...) {
1223   guarantee(_name == NULL, "Only get to set name once.");
1224   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1225   guarantee(_name != NULL, "alloc failure");
1226   va_list ap;
1227   va_start(ap, format);
1228   jio_vsnprintf(_name, max_name_len, format, ap);
1229   va_end(ap);
1230 }
1231 
1232 // ======= WatcherThread ========
1233 
1234 // The watcher thread exists to simulate timer interrupts.  It should
1235 // be replaced by an abstraction over whatever native support for
1236 // timer interrupts exists on the platform.
1237 
1238 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1239 bool WatcherThread::_startable = false;
1240 volatile bool  WatcherThread::_should_terminate = false;
1241 
1242 WatcherThread::WatcherThread() : Thread() {
1243   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1244   if (os::create_thread(this, os::watcher_thread)) {
1245     _watcher_thread = this;
1246 
1247     // Set the watcher thread to the highest OS priority which should not be
1248     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1249     // is created. The only normal thread using this priority is the reference
1250     // handler thread, which runs for very short intervals only.
1251     // If the VMThread's priority is not lower than the WatcherThread profiling
1252     // will be inaccurate.
1253     os::set_priority(this, MaxPriority);
1254     if (!DisableStartThread) {
1255       os::start_thread(this);
1256     }
1257   }
1258 }
1259 
1260 int WatcherThread::sleep() const {
1261   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1262 
1263   // remaining will be zero if there are no tasks,
1264   // causing the WatcherThread to sleep until a task is
1265   // enrolled
1266   int remaining = PeriodicTask::time_to_wait();
1267   int time_slept = 0;
1268 
1269   // we expect this to timeout - we only ever get unparked when
1270   // we should terminate or when a new task has been enrolled
1271   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1272 
1273   jlong time_before_loop = os::javaTimeNanos();
1274 
1275   for (;;) {
1276     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1277     jlong now = os::javaTimeNanos();
1278 
1279     if (remaining == 0) {
1280         // if we didn't have any tasks we could have waited for a long time
1281         // consider the time_slept zero and reset time_before_loop
1282         time_slept = 0;
1283         time_before_loop = now;
1284     } else {
1285         // need to recalulate since we might have new tasks in _tasks
1286         time_slept = (int) ((now - time_before_loop) / 1000000);
1287     }
1288 
1289     // Change to task list or spurious wakeup of some kind
1290     if (timedout || _should_terminate) {
1291         break;
1292     }
1293 
1294     remaining = PeriodicTask::time_to_wait();
1295     if (remaining == 0) {
1296         // Last task was just disenrolled so loop around and wait until
1297         // another task gets enrolled
1298         continue;
1299     }
1300 
1301     remaining -= time_slept;
1302     if (remaining <= 0)
1303       break;
1304   }
1305 
1306   return time_slept;
1307 }
1308 
1309 void WatcherThread::run() {
1310   assert(this == watcher_thread(), "just checking");
1311 
1312   this->record_stack_base_and_size();
1313   this->initialize_thread_local_storage();
1314   this->set_native_thread_name(this->name());
1315   this->set_active_handles(JNIHandleBlock::allocate_block());
1316   while(!_should_terminate) {
1317     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1318     assert(watcher_thread() == this,  "thread consistency check");
1319 
1320     // Calculate how long it'll be until the next PeriodicTask work
1321     // should be done, and sleep that amount of time.
1322     int time_waited = sleep();
1323 
1324     if (is_error_reported()) {
1325       // A fatal error has happened, the error handler(VMError::report_and_die)
1326       // should abort JVM after creating an error log file. However in some
1327       // rare cases, the error handler itself might deadlock. Here we try to
1328       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1329       //
1330       // This code is in WatcherThread because WatcherThread wakes up
1331       // periodically so the fatal error handler doesn't need to do anything;
1332       // also because the WatcherThread is less likely to crash than other
1333       // threads.
1334 
1335       for (;;) {
1336         if (!ShowMessageBoxOnError
1337          && (OnError == NULL || OnError[0] == '\0')
1338          && Arguments::abort_hook() == NULL) {
1339              os::sleep(this, 2 * 60 * 1000, false);
1340              fdStream err(defaultStream::output_fd());
1341              err.print_raw_cr("# [ timer expired, abort... ]");
1342              // skip atexit/vm_exit/vm_abort hooks
1343              os::die();
1344         }
1345 
1346         // Wake up 5 seconds later, the fatal handler may reset OnError or
1347         // ShowMessageBoxOnError when it is ready to abort.
1348         os::sleep(this, 5 * 1000, false);
1349       }
1350     }
1351 
1352     PeriodicTask::real_time_tick(time_waited);
1353   }
1354 
1355   // Signal that it is terminated
1356   {
1357     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1358     _watcher_thread = NULL;
1359     Terminator_lock->notify();
1360   }
1361 
1362   // Thread destructor usually does this..
1363   ThreadLocalStorage::set_thread(NULL);
1364 }
1365 
1366 void WatcherThread::start() {
1367   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1368 
1369   if (watcher_thread() == NULL && _startable) {
1370     _should_terminate = false;
1371     // Create the single instance of WatcherThread
1372     new WatcherThread();
1373   }
1374 }
1375 
1376 void WatcherThread::make_startable() {
1377   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1378   _startable = true;
1379 }
1380 
1381 void WatcherThread::stop() {
1382   {
1383     MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1384     _should_terminate = true;
1385     OrderAccess::fence();  // ensure WatcherThread sees update in main loop
1386 
1387     WatcherThread* watcher = watcher_thread();
1388     if (watcher != NULL)
1389       watcher->unpark();
1390   }
1391 
1392   // it is ok to take late safepoints here, if needed
1393   MutexLocker mu(Terminator_lock);
1394 
1395   while(watcher_thread() != NULL) {
1396     // This wait should make safepoint checks, wait without a timeout,
1397     // and wait as a suspend-equivalent condition.
1398     //
1399     // Note: If the FlatProfiler is running, then this thread is waiting
1400     // for the WatcherThread to terminate and the WatcherThread, via the
1401     // FlatProfiler task, is waiting for the external suspend request on
1402     // this thread to complete. wait_for_ext_suspend_completion() will
1403     // eventually timeout, but that takes time. Making this wait a
1404     // suspend-equivalent condition solves that timeout problem.
1405     //
1406     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1407                           Mutex::_as_suspend_equivalent_flag);
1408   }
1409 }
1410 
1411 void WatcherThread::unpark() {
1412   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1413   PeriodicTask_lock->notify();
1414 }
1415 
1416 void WatcherThread::print_on(outputStream* st) const {
1417   st->print("\"%s\" ", name());
1418   Thread::print_on(st);
1419   st->cr();
1420 }
1421 
1422 // ======= JavaThread ========
1423 
1424 // A JavaThread is a normal Java thread
1425 
1426 void JavaThread::initialize() {
1427   // Initialize fields
1428 
1429   // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1430   set_claimed_par_id(UINT_MAX);
1431 
1432   set_saved_exception_pc(NULL);
1433   set_threadObj(NULL);
1434   _anchor.clear();
1435   set_entry_point(NULL);
1436   set_jni_functions(jni_functions());
1437   set_callee_target(NULL);
1438   set_vm_result(NULL);
1439   set_vm_result_2(NULL);
1440   set_vframe_array_head(NULL);
1441   set_vframe_array_last(NULL);
1442   set_deferred_locals(NULL);
1443   set_deopt_mark(NULL);
1444   set_deopt_nmethod(NULL);
1445   clear_must_deopt_id();
1446   set_monitor_chunks(NULL);
1447   set_next(NULL);
1448   set_thread_state(_thread_new);
1449   _terminated = _not_terminated;
1450   _privileged_stack_top = NULL;
1451   _array_for_gc = NULL;
1452   _suspend_equivalent = false;
1453   _in_deopt_handler = 0;
1454   _doing_unsafe_access = false;
1455   _stack_guard_state = stack_guard_unused;
1456   (void)const_cast<oop&>(_exception_oop = oop(NULL));
1457   _exception_pc  = 0;
1458   _exception_handler_pc = 0;
1459   _is_method_handle_return = 0;
1460   _jvmti_thread_state= NULL;
1461   _should_post_on_exceptions_flag = JNI_FALSE;
1462   _jvmti_get_loaded_classes_closure = NULL;
1463   _interp_only_mode    = 0;
1464   _special_runtime_exit_condition = _no_async_condition;
1465   _pending_async_exception = NULL;
1466   _thread_stat = NULL;
1467   _thread_stat = new ThreadStatistics();
1468   _blocked_on_compilation = false;
1469   _jni_active_critical = 0;
1470   _pending_jni_exception_check_fn = NULL;
1471   _do_not_unlock_if_synchronized = false;
1472   _cached_monitor_info = NULL;
1473   _parker = Parker::Allocate(this) ;
1474 
1475 #ifndef PRODUCT
1476   _jmp_ring_index = 0;
1477   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1478     record_jump(NULL, NULL, NULL, 0);
1479   }
1480 #endif /* PRODUCT */
1481 
1482   set_thread_profiler(NULL);
1483   if (FlatProfiler::is_active()) {
1484     // This is where we would decide to either give each thread it's own profiler
1485     // or use one global one from FlatProfiler,
1486     // or up to some count of the number of profiled threads, etc.
1487     ThreadProfiler* pp = new ThreadProfiler();
1488     pp->engage();
1489     set_thread_profiler(pp);
1490   }
1491 
1492   // Setup safepoint state info for this thread
1493   ThreadSafepointState::create(this);
1494 
1495   debug_only(_java_call_counter = 0);
1496 
1497   // JVMTI PopFrame support
1498   _popframe_condition = popframe_inactive;
1499   _popframe_preserved_args = NULL;
1500   _popframe_preserved_args_size = 0;
1501   _frames_to_pop_failed_realloc = 0;
1502 
1503   pd_initialize();
1504 }
1505 
1506 #if INCLUDE_ALL_GCS
1507 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1508 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1509 #endif // INCLUDE_ALL_GCS
1510 
1511 JavaThread::JavaThread(bool is_attaching_via_jni) :
1512   Thread()
1513 #if INCLUDE_ALL_GCS
1514   , _satb_mark_queue(&_satb_mark_queue_set),
1515   _dirty_card_queue(&_dirty_card_queue_set)
1516 #endif // INCLUDE_ALL_GCS
1517 {
1518   initialize();
1519   if (is_attaching_via_jni) {
1520     _jni_attach_state = _attaching_via_jni;
1521   } else {
1522     _jni_attach_state = _not_attaching_via_jni;
1523   }
1524   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1525 }
1526 
1527 bool JavaThread::reguard_stack(address cur_sp) {
1528   if (_stack_guard_state != stack_guard_yellow_disabled) {
1529     return true; // Stack already guarded or guard pages not needed.
1530   }
1531 
1532   if (register_stack_overflow()) {
1533     // For those architectures which have separate register and
1534     // memory stacks, we must check the register stack to see if
1535     // it has overflowed.
1536     return false;
1537   }
1538 
1539   // Java code never executes within the yellow zone: the latter is only
1540   // there to provoke an exception during stack banging.  If java code
1541   // is executing there, either StackShadowPages should be larger, or
1542   // some exception code in c1, c2 or the interpreter isn't unwinding
1543   // when it should.
1544   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1545 
1546   enable_stack_yellow_zone();
1547   return true;
1548 }
1549 
1550 bool JavaThread::reguard_stack(void) {
1551   return reguard_stack(os::current_stack_pointer());
1552 }
1553 
1554 
1555 void JavaThread::block_if_vm_exited() {
1556   if (_terminated == _vm_exited) {
1557     // _vm_exited is set at safepoint, and Threads_lock is never released
1558     // we will block here forever
1559     Threads_lock->lock_without_safepoint_check();
1560     ShouldNotReachHere();
1561   }
1562 }
1563 
1564 
1565 // Remove this ifdef when C1 is ported to the compiler interface.
1566 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1567 
1568 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1569   Thread()
1570 #if INCLUDE_ALL_GCS
1571   , _satb_mark_queue(&_satb_mark_queue_set),
1572   _dirty_card_queue(&_dirty_card_queue_set)
1573 #endif // INCLUDE_ALL_GCS
1574 {
1575   if (TraceThreadEvents) {
1576     tty->print_cr("creating thread %p", this);
1577   }
1578   initialize();
1579   _jni_attach_state = _not_attaching_via_jni;
1580   set_entry_point(entry_point);
1581   // Create the native thread itself.
1582   // %note runtime_23
1583   os::ThreadType thr_type = os::java_thread;
1584   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1585                                                      os::java_thread;
1586   os::create_thread(this, thr_type, stack_sz);
1587   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1588   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1589   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1590   // the exception consists of creating the exception object & initializing it, initialization
1591   // will leave the VM via a JavaCall and then all locks must be unlocked).
1592   //
1593   // The thread is still suspended when we reach here. Thread must be explicit started
1594   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1595   // by calling Threads:add. The reason why this is not done here, is because the thread
1596   // object must be fully initialized (take a look at JVM_Start)
1597 }
1598 
1599 JavaThread::~JavaThread() {
1600   if (TraceThreadEvents) {
1601       tty->print_cr("terminate thread %p", this);
1602   }
1603 
1604   // JSR166 -- return the parker to the free list
1605   Parker::Release(_parker);
1606   _parker = NULL ;
1607 
1608   // Free any remaining  previous UnrollBlock
1609   vframeArray* old_array = vframe_array_last();
1610 
1611   if (old_array != NULL) {
1612     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1613     old_array->set_unroll_block(NULL);
1614     delete old_info;
1615     delete old_array;
1616   }
1617 
1618   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1619   if (deferred != NULL) {
1620     // This can only happen if thread is destroyed before deoptimization occurs.
1621     assert(deferred->length() != 0, "empty array!");
1622     do {
1623       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1624       deferred->remove_at(0);
1625       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1626       delete dlv;
1627     } while (deferred->length() != 0);
1628     delete deferred;
1629   }
1630 
1631   // All Java related clean up happens in exit
1632   ThreadSafepointState::destroy(this);
1633   if (_thread_profiler != NULL) delete _thread_profiler;
1634   if (_thread_stat != NULL) delete _thread_stat;
1635 }
1636 
1637 
1638 // The first routine called by a new Java thread
1639 void JavaThread::run() {
1640   // initialize thread-local alloc buffer related fields
1641   this->initialize_tlab();
1642 
1643   // used to test validitity of stack trace backs
1644   this->record_base_of_stack_pointer();
1645 
1646   // Record real stack base and size.
1647   this->record_stack_base_and_size();
1648 
1649   // Initialize thread local storage; set before calling MutexLocker
1650   this->initialize_thread_local_storage();
1651 
1652   this->create_stack_guard_pages();
1653 
1654   this->cache_global_variables();
1655 
1656   // Thread is now sufficient initialized to be handled by the safepoint code as being
1657   // in the VM. Change thread state from _thread_new to _thread_in_vm
1658   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1659 
1660   assert(JavaThread::current() == this, "sanity check");
1661   assert(!Thread::current()->owns_locks(), "sanity check");
1662 
1663   DTRACE_THREAD_PROBE(start, this);
1664 
1665   // This operation might block. We call that after all safepoint checks for a new thread has
1666   // been completed.
1667   this->set_active_handles(JNIHandleBlock::allocate_block());
1668 
1669   if (JvmtiExport::should_post_thread_life()) {
1670     JvmtiExport::post_thread_start(this);
1671   }
1672 
1673   JFR_ONLY(Jfr::on_thread_start(this);)
1674 
1675   // We call another function to do the rest so we are sure that the stack addresses used
1676   // from there will be lower than the stack base just computed
1677   thread_main_inner();
1678 
1679   // Note, thread is no longer valid at this point!
1680 }
1681 
1682 
1683 void JavaThread::thread_main_inner() {
1684   assert(JavaThread::current() == this, "sanity check");
1685   assert(this->threadObj() != NULL, "just checking");
1686 
1687   // Execute thread entry point unless this thread has a pending exception
1688   // or has been stopped before starting.
1689   // Note: Due to JVM_StopThread we can have pending exceptions already!
1690   if (!this->has_pending_exception() &&
1691       !java_lang_Thread::is_stillborn(this->threadObj())) {
1692     {
1693       ResourceMark rm(this);
1694       this->set_native_thread_name(this->get_thread_name());
1695     }
1696     HandleMark hm(this);
1697     this->entry_point()(this, this);
1698   }
1699 
1700   DTRACE_THREAD_PROBE(stop, this);
1701 
1702   this->exit(false);
1703   delete this;
1704 }
1705 
1706 
1707 static void ensure_join(JavaThread* thread) {
1708   // We do not need to grap the Threads_lock, since we are operating on ourself.
1709   Handle threadObj(thread, thread->threadObj());
1710   assert(threadObj.not_null(), "java thread object must exist");
1711   ObjectLocker lock(threadObj, thread);
1712   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1713   thread->clear_pending_exception();
1714   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1715   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1716   // Clear the native thread instance - this makes isAlive return false and allows the join()
1717   // to complete once we've done the notify_all below
1718   java_lang_Thread::set_thread(threadObj(), NULL);
1719   lock.notify_all(thread);
1720   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1721   thread->clear_pending_exception();
1722 }
1723 
1724 
1725 // For any new cleanup additions, please check to see if they need to be applied to
1726 // cleanup_failed_attach_current_thread as well.
1727 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1728   assert(this == JavaThread::current(),  "thread consistency check");
1729 
1730   HandleMark hm(this);
1731   Handle uncaught_exception(this, this->pending_exception());
1732   this->clear_pending_exception();
1733   Handle threadObj(this, this->threadObj());
1734   assert(threadObj.not_null(), "Java thread object should be created");
1735 
1736   if (get_thread_profiler() != NULL) {
1737     get_thread_profiler()->disengage();
1738     ResourceMark rm;
1739     get_thread_profiler()->print(get_thread_name());
1740   }
1741 
1742 
1743   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1744   {
1745     EXCEPTION_MARK;
1746 
1747     CLEAR_PENDING_EXCEPTION;
1748   }
1749   // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1750   // has to be fixed by a runtime query method
1751   if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1752     // JSR-166: change call from from ThreadGroup.uncaughtException to
1753     // java.lang.Thread.dispatchUncaughtException
1754     if (uncaught_exception.not_null()) {
1755       Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1756       {
1757         EXCEPTION_MARK;
1758         // Check if the method Thread.dispatchUncaughtException() exists. If so
1759         // call it.  Otherwise we have an older library without the JSR-166 changes,
1760         // so call ThreadGroup.uncaughtException()
1761         KlassHandle recvrKlass(THREAD, threadObj->klass());
1762         CallInfo callinfo;
1763         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1764         LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1765                                            vmSymbols::dispatchUncaughtException_name(),
1766                                            vmSymbols::throwable_void_signature(),
1767                                            KlassHandle(), false, false, THREAD);
1768         CLEAR_PENDING_EXCEPTION;
1769         methodHandle method = callinfo.selected_method();
1770         if (method.not_null()) {
1771           JavaValue result(T_VOID);
1772           JavaCalls::call_virtual(&result,
1773                                   threadObj, thread_klass,
1774                                   vmSymbols::dispatchUncaughtException_name(),
1775                                   vmSymbols::throwable_void_signature(),
1776                                   uncaught_exception,
1777                                   THREAD);
1778         } else {
1779           KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1780           JavaValue result(T_VOID);
1781           JavaCalls::call_virtual(&result,
1782                                   group, thread_group,
1783                                   vmSymbols::uncaughtException_name(),
1784                                   vmSymbols::thread_throwable_void_signature(),
1785                                   threadObj,           // Arg 1
1786                                   uncaught_exception,  // Arg 2
1787                                   THREAD);
1788         }
1789         if (HAS_PENDING_EXCEPTION) {
1790           ResourceMark rm(this);
1791           jio_fprintf(defaultStream::error_stream(),
1792                 "\nException: %s thrown from the UncaughtExceptionHandler"
1793                 " in thread \"%s\"\n",
1794                 pending_exception()->klass()->external_name(),
1795                 get_thread_name());
1796           CLEAR_PENDING_EXCEPTION;
1797         }
1798       }
1799     }
1800     JFR_ONLY(Jfr::on_java_thread_dismantle(this);)
1801 
1802     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1803     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1804     // is deprecated anyhow.
1805     if (!is_Compiler_thread()) {
1806       int count = 3;
1807       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1808         EXCEPTION_MARK;
1809         JavaValue result(T_VOID);
1810         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1811         JavaCalls::call_virtual(&result,
1812                               threadObj, thread_klass,
1813                               vmSymbols::exit_method_name(),
1814                               vmSymbols::void_method_signature(),
1815                               THREAD);
1816         CLEAR_PENDING_EXCEPTION;
1817       }
1818     }
1819     // notify JVMTI
1820     if (JvmtiExport::should_post_thread_life()) {
1821       JvmtiExport::post_thread_end(this);
1822     }
1823 
1824     // We have notified the agents that we are exiting, before we go on,
1825     // we must check for a pending external suspend request and honor it
1826     // in order to not surprise the thread that made the suspend request.
1827     while (true) {
1828       {
1829         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1830         if (!is_external_suspend()) {
1831           set_terminated(_thread_exiting);
1832           ThreadService::current_thread_exiting(this);
1833           break;
1834         }
1835         // Implied else:
1836         // Things get a little tricky here. We have a pending external
1837         // suspend request, but we are holding the SR_lock so we
1838         // can't just self-suspend. So we temporarily drop the lock
1839         // and then self-suspend.
1840       }
1841 
1842       ThreadBlockInVM tbivm(this);
1843       java_suspend_self();
1844 
1845       // We're done with this suspend request, but we have to loop around
1846       // and check again. Eventually we will get SR_lock without a pending
1847       // external suspend request and will be able to mark ourselves as
1848       // exiting.
1849     }
1850     // no more external suspends are allowed at this point
1851   } else {
1852     // before_exit() has already posted JVMTI THREAD_END events
1853   }
1854 
1855   // Notify waiters on thread object. This has to be done after exit() is called
1856   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1857   // group should have the destroyed bit set before waiters are notified).
1858   ensure_join(this);
1859   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1860 
1861   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1862   // held by this thread must be released.  A detach operation must only
1863   // get here if there are no Java frames on the stack.  Therefore, any
1864   // owned monitors at this point MUST be JNI-acquired monitors which are
1865   // pre-inflated and in the monitor cache.
1866   //
1867   // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1868   if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1869     assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1870     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1871     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1872   }
1873 
1874   // These things needs to be done while we are still a Java Thread. Make sure that thread
1875   // is in a consistent state, in case GC happens
1876   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1877   JFR_ONLY(Jfr::on_thread_exit(this);)
1878 
1879   if (active_handles() != NULL) {
1880     JNIHandleBlock* block = active_handles();
1881     set_active_handles(NULL);
1882     JNIHandleBlock::release_block(block);
1883   }
1884 
1885   if (free_handle_block() != NULL) {
1886     JNIHandleBlock* block = free_handle_block();
1887     set_free_handle_block(NULL);
1888     JNIHandleBlock::release_block(block);
1889   }
1890 
1891   // These have to be removed while this is still a valid thread.
1892   remove_stack_guard_pages();
1893 
1894   if (UseTLAB) {
1895     tlab().make_parsable(true);  // retire TLAB
1896   }
1897 
1898   if (JvmtiEnv::environments_might_exist()) {
1899     JvmtiExport::cleanup_thread(this);
1900   }
1901 
1902   // We must flush any deferred card marks before removing a thread from
1903   // the list of active threads.
1904   Universe::heap()->flush_deferred_store_barrier(this);
1905   assert(deferred_card_mark().is_empty(), "Should have been flushed");
1906 
1907 #if INCLUDE_ALL_GCS
1908   // We must flush the G1-related buffers before removing a thread
1909   // from the list of active threads. We must do this after any deferred
1910   // card marks have been flushed (above) so that any entries that are
1911   // added to the thread's dirty card queue as a result are not lost.
1912   if (UseG1GC) {
1913     flush_barrier_queues();
1914   }
1915 #endif // INCLUDE_ALL_GCS
1916 
1917   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1918   Threads::remove(this);
1919 }
1920 
1921 #if INCLUDE_ALL_GCS
1922 // Flush G1-related queues.
1923 void JavaThread::flush_barrier_queues() {
1924   satb_mark_queue().flush();
1925   dirty_card_queue().flush();
1926 }
1927 
1928 void JavaThread::initialize_queues() {
1929   assert(!SafepointSynchronize::is_at_safepoint(),
1930          "we should not be at a safepoint");
1931 
1932   ObjPtrQueue& satb_queue = satb_mark_queue();
1933   SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1934   // The SATB queue should have been constructed with its active
1935   // field set to false.
1936   assert(!satb_queue.is_active(), "SATB queue should not be active");
1937   assert(satb_queue.is_empty(), "SATB queue should be empty");
1938   // If we are creating the thread during a marking cycle, we should
1939   // set the active field of the SATB queue to true.
1940   if (satb_queue_set.is_active()) {
1941     satb_queue.set_active(true);
1942   }
1943 
1944   DirtyCardQueue& dirty_queue = dirty_card_queue();
1945   // The dirty card queue should have been constructed with its
1946   // active field set to true.
1947   assert(dirty_queue.is_active(), "dirty card queue should be active");
1948 }
1949 #endif // INCLUDE_ALL_GCS
1950 
1951 void JavaThread::cleanup_failed_attach_current_thread() {
1952   if (get_thread_profiler() != NULL) {
1953     get_thread_profiler()->disengage();
1954     ResourceMark rm;
1955     get_thread_profiler()->print(get_thread_name());
1956   }
1957 
1958   if (active_handles() != NULL) {
1959     JNIHandleBlock* block = active_handles();
1960     set_active_handles(NULL);
1961     JNIHandleBlock::release_block(block);
1962   }
1963 
1964   if (free_handle_block() != NULL) {
1965     JNIHandleBlock* block = free_handle_block();
1966     set_free_handle_block(NULL);
1967     JNIHandleBlock::release_block(block);
1968   }
1969 
1970   // These have to be removed while this is still a valid thread.
1971   remove_stack_guard_pages();
1972 
1973   if (UseTLAB) {
1974     tlab().make_parsable(true);  // retire TLAB, if any
1975   }
1976 
1977 #if INCLUDE_ALL_GCS
1978   if (UseG1GC) {
1979     flush_barrier_queues();
1980   }
1981 #endif // INCLUDE_ALL_GCS
1982 
1983   Threads::remove(this);
1984   delete this;
1985 }
1986 
1987 
1988 
1989 
1990 JavaThread* JavaThread::active() {
1991   Thread* thread = ThreadLocalStorage::thread();
1992   assert(thread != NULL, "just checking");
1993   if (thread->is_Java_thread()) {
1994     return (JavaThread*) thread;
1995   } else {
1996     assert(thread->is_VM_thread(), "this must be a vm thread");
1997     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1998     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1999     assert(ret->is_Java_thread(), "must be a Java thread");
2000     return ret;
2001   }
2002 }
2003 
2004 bool JavaThread::is_lock_owned(address adr) const {
2005   if (Thread::is_lock_owned(adr)) return true;
2006 
2007   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2008     if (chunk->contains(adr)) return true;
2009   }
2010 
2011   return false;
2012 }
2013 
2014 
2015 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2016   chunk->set_next(monitor_chunks());
2017   set_monitor_chunks(chunk);
2018 }
2019 
2020 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2021   guarantee(monitor_chunks() != NULL, "must be non empty");
2022   if (monitor_chunks() == chunk) {
2023     set_monitor_chunks(chunk->next());
2024   } else {
2025     MonitorChunk* prev = monitor_chunks();
2026     while (prev->next() != chunk) prev = prev->next();
2027     prev->set_next(chunk->next());
2028   }
2029 }
2030 
2031 // JVM support.
2032 
2033 // Note: this function shouldn't block if it's called in
2034 // _thread_in_native_trans state (such as from
2035 // check_special_condition_for_native_trans()).
2036 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2037 
2038   if (has_last_Java_frame() && has_async_condition()) {
2039     // If we are at a polling page safepoint (not a poll return)
2040     // then we must defer async exception because live registers
2041     // will be clobbered by the exception path. Poll return is
2042     // ok because the call we a returning from already collides
2043     // with exception handling registers and so there is no issue.
2044     // (The exception handling path kills call result registers but
2045     //  this is ok since the exception kills the result anyway).
2046 
2047     if (is_at_poll_safepoint()) {
2048       // if the code we are returning to has deoptimized we must defer
2049       // the exception otherwise live registers get clobbered on the
2050       // exception path before deoptimization is able to retrieve them.
2051       //
2052       RegisterMap map(this, false);
2053       frame caller_fr = last_frame().sender(&map);
2054       assert(caller_fr.is_compiled_frame(), "what?");
2055       if (caller_fr.is_deoptimized_frame()) {
2056         if (TraceExceptions) {
2057           ResourceMark rm;
2058           tty->print_cr("deferred async exception at compiled safepoint");
2059         }
2060         return;
2061       }
2062     }
2063   }
2064 
2065   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2066   if (condition == _no_async_condition) {
2067     // Conditions have changed since has_special_runtime_exit_condition()
2068     // was called:
2069     // - if we were here only because of an external suspend request,
2070     //   then that was taken care of above (or cancelled) so we are done
2071     // - if we were here because of another async request, then it has
2072     //   been cleared between the has_special_runtime_exit_condition()
2073     //   and now so again we are done
2074     return;
2075   }
2076 
2077   // Check for pending async. exception
2078   if (_pending_async_exception != NULL) {
2079     // Only overwrite an already pending exception, if it is not a threadDeath.
2080     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2081 
2082       // We cannot call Exceptions::_throw(...) here because we cannot block
2083       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2084 
2085       if (TraceExceptions) {
2086         ResourceMark rm;
2087         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2088         if (has_last_Java_frame() ) {
2089           frame f = last_frame();
2090           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2091         }
2092         tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2093       }
2094       _pending_async_exception = NULL;
2095       clear_has_async_exception();
2096     }
2097   }
2098 
2099   if (check_unsafe_error &&
2100       condition == _async_unsafe_access_error && !has_pending_exception()) {
2101     condition = _no_async_condition;  // done
2102     switch (thread_state()) {
2103     case _thread_in_vm:
2104       {
2105         JavaThread* THREAD = this;
2106         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2107       }
2108     case _thread_in_native:
2109       {
2110         ThreadInVMfromNative tiv(this);
2111         JavaThread* THREAD = this;
2112         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2113       }
2114     case _thread_in_Java:
2115       {
2116         ThreadInVMfromJava tiv(this);
2117         JavaThread* THREAD = this;
2118         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2119       }
2120     default:
2121       ShouldNotReachHere();
2122     }
2123   }
2124 
2125   assert(condition == _no_async_condition || has_pending_exception() ||
2126          (!check_unsafe_error && condition == _async_unsafe_access_error),
2127          "must have handled the async condition, if no exception");
2128 }
2129 
2130 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2131   //
2132   // Check for pending external suspend. Internal suspend requests do
2133   // not use handle_special_runtime_exit_condition().
2134   // If JNIEnv proxies are allowed, don't self-suspend if the target
2135   // thread is not the current thread. In older versions of jdbx, jdbx
2136   // threads could call into the VM with another thread's JNIEnv so we
2137   // can be here operating on behalf of a suspended thread (4432884).
2138   bool do_self_suspend = is_external_suspend_with_lock();
2139   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2140     //
2141     // Because thread is external suspended the safepoint code will count
2142     // thread as at a safepoint. This can be odd because we can be here
2143     // as _thread_in_Java which would normally transition to _thread_blocked
2144     // at a safepoint. We would like to mark the thread as _thread_blocked
2145     // before calling java_suspend_self like all other callers of it but
2146     // we must then observe proper safepoint protocol. (We can't leave
2147     // _thread_blocked with a safepoint in progress). However we can be
2148     // here as _thread_in_native_trans so we can't use a normal transition
2149     // constructor/destructor pair because they assert on that type of
2150     // transition. We could do something like:
2151     //
2152     // JavaThreadState state = thread_state();
2153     // set_thread_state(_thread_in_vm);
2154     // {
2155     //   ThreadBlockInVM tbivm(this);
2156     //   java_suspend_self()
2157     // }
2158     // set_thread_state(_thread_in_vm_trans);
2159     // if (safepoint) block;
2160     // set_thread_state(state);
2161     //
2162     // but that is pretty messy. Instead we just go with the way the
2163     // code has worked before and note that this is the only path to
2164     // java_suspend_self that doesn't put the thread in _thread_blocked
2165     // mode.
2166 
2167     frame_anchor()->make_walkable(this);
2168     java_suspend_self();
2169 
2170     // We might be here for reasons in addition to the self-suspend request
2171     // so check for other async requests.
2172   }
2173 
2174   if (check_asyncs) {
2175     check_and_handle_async_exceptions();
2176   }
2177 
2178   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2179 }
2180 
2181 void JavaThread::send_thread_stop(oop java_throwable)  {
2182   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2183   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2184   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2185 
2186   // Do not throw asynchronous exceptions against the compiler thread
2187   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2188   if (is_Compiler_thread()) return;
2189 
2190   {
2191     // Actually throw the Throwable against the target Thread - however
2192     // only if there is no thread death exception installed already.
2193     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2194       // If the topmost frame is a runtime stub, then we are calling into
2195       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2196       // must deoptimize the caller before continuing, as the compiled  exception handler table
2197       // may not be valid
2198       if (has_last_Java_frame()) {
2199         frame f = last_frame();
2200         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2201           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2202           RegisterMap reg_map(this, UseBiasedLocking);
2203           frame compiled_frame = f.sender(&reg_map);
2204           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2205             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2206           }
2207         }
2208       }
2209 
2210       // Set async. pending exception in thread.
2211       set_pending_async_exception(java_throwable);
2212 
2213       if (TraceExceptions) {
2214        ResourceMark rm;
2215        tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2216       }
2217       // for AbortVMOnException flag
2218       NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2219     }
2220   }
2221 
2222 
2223   // Interrupt thread so it will wake up from a potential wait()
2224   Thread::interrupt(this);
2225 }
2226 
2227 // External suspension mechanism.
2228 //
2229 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2230 // to any VM_locks and it is at a transition
2231 // Self-suspension will happen on the transition out of the vm.
2232 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2233 //
2234 // Guarantees on return:
2235 //   + Target thread will not execute any new bytecode (that's why we need to
2236 //     force a safepoint)
2237 //   + Target thread will not enter any new monitors
2238 //
2239 void JavaThread::java_suspend() {
2240   { MutexLocker mu(Threads_lock);
2241     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2242        return;
2243     }
2244   }
2245 
2246   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2247     if (!is_external_suspend()) {
2248       // a racing resume has cancelled us; bail out now
2249       return;
2250     }
2251 
2252     // suspend is done
2253     uint32_t debug_bits = 0;
2254     // Warning: is_ext_suspend_completed() may temporarily drop the
2255     // SR_lock to allow the thread to reach a stable thread state if
2256     // it is currently in a transient thread state.
2257     if (is_ext_suspend_completed(false /* !called_by_wait */,
2258                                  SuspendRetryDelay, &debug_bits) ) {
2259       return;
2260     }
2261   }
2262 
2263   VM_ForceSafepoint vm_suspend;
2264   VMThread::execute(&vm_suspend);
2265 }
2266 
2267 // Part II of external suspension.
2268 // A JavaThread self suspends when it detects a pending external suspend
2269 // request. This is usually on transitions. It is also done in places
2270 // where continuing to the next transition would surprise the caller,
2271 // e.g., monitor entry.
2272 //
2273 // Returns the number of times that the thread self-suspended.
2274 //
2275 // Note: DO NOT call java_suspend_self() when you just want to block current
2276 //       thread. java_suspend_self() is the second stage of cooperative
2277 //       suspension for external suspend requests and should only be used
2278 //       to complete an external suspend request.
2279 //
2280 int JavaThread::java_suspend_self() {
2281   int ret = 0;
2282 
2283   // we are in the process of exiting so don't suspend
2284   if (is_exiting()) {
2285      clear_external_suspend();
2286      return ret;
2287   }
2288 
2289   assert(_anchor.walkable() ||
2290     (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2291     "must have walkable stack");
2292 
2293   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2294 
2295   assert(!this->is_ext_suspended(),
2296     "a thread trying to self-suspend should not already be suspended");
2297 
2298   if (this->is_suspend_equivalent()) {
2299     // If we are self-suspending as a result of the lifting of a
2300     // suspend equivalent condition, then the suspend_equivalent
2301     // flag is not cleared until we set the ext_suspended flag so
2302     // that wait_for_ext_suspend_completion() returns consistent
2303     // results.
2304     this->clear_suspend_equivalent();
2305   }
2306 
2307   // A racing resume may have cancelled us before we grabbed SR_lock
2308   // above. Or another external suspend request could be waiting for us
2309   // by the time we return from SR_lock()->wait(). The thread
2310   // that requested the suspension may already be trying to walk our
2311   // stack and if we return now, we can change the stack out from under
2312   // it. This would be a "bad thing (TM)" and cause the stack walker
2313   // to crash. We stay self-suspended until there are no more pending
2314   // external suspend requests.
2315   while (is_external_suspend()) {
2316     ret++;
2317     this->set_ext_suspended();
2318 
2319     // _ext_suspended flag is cleared by java_resume()
2320     while (is_ext_suspended()) {
2321       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2322     }
2323   }
2324 
2325   return ret;
2326 }
2327 
2328 #ifdef ASSERT
2329 // verify the JavaThread has not yet been published in the Threads::list, and
2330 // hence doesn't need protection from concurrent access at this stage
2331 void JavaThread::verify_not_published() {
2332   if (!Threads_lock->owned_by_self()) {
2333    MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
2334    assert( !Threads::includes(this),
2335            "java thread shouldn't have been published yet!");
2336   }
2337   else {
2338    assert( !Threads::includes(this),
2339            "java thread shouldn't have been published yet!");
2340   }
2341 }
2342 #endif
2343 
2344 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2345 // progress or when _suspend_flags is non-zero.
2346 // Current thread needs to self-suspend if there is a suspend request and/or
2347 // block if a safepoint is in progress.
2348 // Async exception ISN'T checked.
2349 // Note only the ThreadInVMfromNative transition can call this function
2350 // directly and when thread state is _thread_in_native_trans
2351 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2352   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2353 
2354   JavaThread *curJT = JavaThread::current();
2355   bool do_self_suspend = thread->is_external_suspend();
2356 
2357   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2358 
2359   // If JNIEnv proxies are allowed, don't self-suspend if the target
2360   // thread is not the current thread. In older versions of jdbx, jdbx
2361   // threads could call into the VM with another thread's JNIEnv so we
2362   // can be here operating on behalf of a suspended thread (4432884).
2363   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2364     JavaThreadState state = thread->thread_state();
2365 
2366     // We mark this thread_blocked state as a suspend-equivalent so
2367     // that a caller to is_ext_suspend_completed() won't be confused.
2368     // The suspend-equivalent state is cleared by java_suspend_self().
2369     thread->set_suspend_equivalent();
2370 
2371     // If the safepoint code sees the _thread_in_native_trans state, it will
2372     // wait until the thread changes to other thread state. There is no
2373     // guarantee on how soon we can obtain the SR_lock and complete the
2374     // self-suspend request. It would be a bad idea to let safepoint wait for
2375     // too long. Temporarily change the state to _thread_blocked to
2376     // let the VM thread know that this thread is ready for GC. The problem
2377     // of changing thread state is that safepoint could happen just after
2378     // java_suspend_self() returns after being resumed, and VM thread will
2379     // see the _thread_blocked state. We must check for safepoint
2380     // after restoring the state and make sure we won't leave while a safepoint
2381     // is in progress.
2382     thread->set_thread_state(_thread_blocked);
2383     thread->java_suspend_self();
2384     thread->set_thread_state(state);
2385     // Make sure new state is seen by VM thread
2386     if (os::is_MP()) {
2387       if (UseMembar) {
2388         // Force a fence between the write above and read below
2389         OrderAccess::fence();
2390       } else {
2391         // Must use this rather than serialization page in particular on Windows
2392         InterfaceSupport::serialize_memory(thread);
2393       }
2394     }
2395   }
2396 
2397   if (SafepointSynchronize::do_call_back()) {
2398     // If we are safepointing, then block the caller which may not be
2399     // the same as the target thread (see above).
2400     SafepointSynchronize::block(curJT);
2401   }
2402 
2403   if (thread->is_deopt_suspend()) {
2404     thread->clear_deopt_suspend();
2405     RegisterMap map(thread, false);
2406     frame f = thread->last_frame();
2407     while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2408       f = f.sender(&map);
2409     }
2410     if (f.id() == thread->must_deopt_id()) {
2411       thread->clear_must_deopt_id();
2412       f.deoptimize(thread);
2413     } else {
2414       fatal("missed deoptimization!");
2415     }
2416   }
2417 
2418   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2419 }
2420 
2421 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2422 // progress or when _suspend_flags is non-zero.
2423 // Current thread needs to self-suspend if there is a suspend request and/or
2424 // block if a safepoint is in progress.
2425 // Also check for pending async exception (not including unsafe access error).
2426 // Note only the native==>VM/Java barriers can call this function and when
2427 // thread state is _thread_in_native_trans.
2428 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2429   check_safepoint_and_suspend_for_native_trans(thread);
2430 
2431   if (thread->has_async_exception()) {
2432     // We are in _thread_in_native_trans state, don't handle unsafe
2433     // access error since that may block.
2434     thread->check_and_handle_async_exceptions(false);
2435   }
2436 }
2437 
2438 // This is a variant of the normal
2439 // check_special_condition_for_native_trans with slightly different
2440 // semantics for use by critical native wrappers.  It does all the
2441 // normal checks but also performs the transition back into
2442 // thread_in_Java state.  This is required so that critical natives
2443 // can potentially block and perform a GC if they are the last thread
2444 // exiting the GC_locker.
2445 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2446   check_special_condition_for_native_trans(thread);
2447 
2448   // Finish the transition
2449   thread->set_thread_state(_thread_in_Java);
2450 
2451   if (thread->do_critical_native_unlock()) {
2452     ThreadInVMfromJavaNoAsyncException tiv(thread);
2453     GC_locker::unlock_critical(thread);
2454     thread->clear_critical_native_unlock();
2455   }
2456 }
2457 
2458 // We need to guarantee the Threads_lock here, since resumes are not
2459 // allowed during safepoint synchronization
2460 // Can only resume from an external suspension
2461 void JavaThread::java_resume() {
2462   assert_locked_or_safepoint(Threads_lock);
2463 
2464   // Sanity check: thread is gone, has started exiting or the thread
2465   // was not externally suspended.
2466   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2467     return;
2468   }
2469 
2470   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2471 
2472   clear_external_suspend();
2473 
2474   if (is_ext_suspended()) {
2475     clear_ext_suspended();
2476     SR_lock()->notify_all();
2477   }
2478 }
2479 
2480 void JavaThread::create_stack_guard_pages() {
2481   if (!os::uses_stack_guard_pages() ||
2482       _stack_guard_state != stack_guard_unused ||
2483       (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2484       if (TraceThreadEvents) {
2485         tty->print_cr("Stack guard page creation for thread "
2486                       UINTX_FORMAT " disabled", os::current_thread_id());
2487       }
2488     return;
2489   }
2490   address low_addr = stack_base() - stack_size();
2491   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2492 
2493   int allocate = os::allocate_stack_guard_pages();
2494   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2495 
2496   if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2497     warning("Attempt to allocate stack guard pages failed.");
2498     return;
2499   }
2500 
2501   if (os::guard_memory((char *) low_addr, len)) {
2502     _stack_guard_state = stack_guard_enabled;
2503   } else {
2504     warning("Attempt to protect stack guard pages failed.");
2505     if (os::uncommit_memory((char *) low_addr, len)) {
2506       warning("Attempt to deallocate stack guard pages failed.");
2507     }
2508   }
2509 }
2510 
2511 void JavaThread::remove_stack_guard_pages() {
2512   assert(Thread::current() == this, "from different thread");
2513   if (_stack_guard_state == stack_guard_unused) return;
2514   address low_addr = stack_base() - stack_size();
2515   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2516 
2517   if (os::allocate_stack_guard_pages()) {
2518     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2519       _stack_guard_state = stack_guard_unused;
2520     } else {
2521       warning("Attempt to deallocate stack guard pages failed.");
2522     }
2523   } else {
2524     if (_stack_guard_state == stack_guard_unused) return;
2525     if (os::unguard_memory((char *) low_addr, len)) {
2526       _stack_guard_state = stack_guard_unused;
2527     } else {
2528         warning("Attempt to unprotect stack guard pages failed.");
2529     }
2530   }
2531 }
2532 
2533 void JavaThread::enable_stack_yellow_zone() {
2534   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2535   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2536 
2537   // The base notation is from the stacks point of view, growing downward.
2538   // We need to adjust it to work correctly with guard_memory()
2539   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2540 
2541   guarantee(base < stack_base(),"Error calculating stack yellow zone");
2542   guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2543 
2544   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2545     _stack_guard_state = stack_guard_enabled;
2546   } else {
2547     warning("Attempt to guard stack yellow zone failed.");
2548   }
2549   enable_register_stack_guard();
2550 }
2551 
2552 void JavaThread::disable_stack_yellow_zone() {
2553   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2554   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2555 
2556   // Simply return if called for a thread that does not use guard pages.
2557   if (_stack_guard_state == stack_guard_unused) return;
2558 
2559   // The base notation is from the stacks point of view, growing downward.
2560   // We need to adjust it to work correctly with guard_memory()
2561   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2562 
2563   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2564     _stack_guard_state = stack_guard_yellow_disabled;
2565   } else {
2566     warning("Attempt to unguard stack yellow zone failed.");
2567   }
2568   disable_register_stack_guard();
2569 }
2570 
2571 void JavaThread::enable_stack_red_zone() {
2572   // The base notation is from the stacks point of view, growing downward.
2573   // We need to adjust it to work correctly with guard_memory()
2574   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2575   address base = stack_red_zone_base() - stack_red_zone_size();
2576 
2577   guarantee(base < stack_base(),"Error calculating stack red zone");
2578   guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2579 
2580   if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2581     warning("Attempt to guard stack red zone failed.");
2582   }
2583 }
2584 
2585 void JavaThread::disable_stack_red_zone() {
2586   // The base notation is from the stacks point of view, growing downward.
2587   // We need to adjust it to work correctly with guard_memory()
2588   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2589   address base = stack_red_zone_base() - stack_red_zone_size();
2590   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2591     warning("Attempt to unguard stack red zone failed.");
2592   }
2593 }
2594 
2595 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2596   // ignore is there is no stack
2597   if (!has_last_Java_frame()) return;
2598   // traverse the stack frames. Starts from top frame.
2599   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2600     frame* fr = fst.current();
2601     f(fr, fst.register_map());
2602   }
2603 }
2604 
2605 
2606 #ifndef PRODUCT
2607 // Deoptimization
2608 // Function for testing deoptimization
2609 void JavaThread::deoptimize() {
2610   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2611   StackFrameStream fst(this, UseBiasedLocking);
2612   bool deopt = false;           // Dump stack only if a deopt actually happens.
2613   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2614   // Iterate over all frames in the thread and deoptimize
2615   for(; !fst.is_done(); fst.next()) {
2616     if(fst.current()->can_be_deoptimized()) {
2617 
2618       if (only_at) {
2619         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2620         // consists of comma or carriage return separated numbers so
2621         // search for the current bci in that string.
2622         address pc = fst.current()->pc();
2623         nmethod* nm =  (nmethod*) fst.current()->cb();
2624         ScopeDesc* sd = nm->scope_desc_at( pc);
2625         char buffer[8];
2626         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2627         size_t len = strlen(buffer);
2628         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2629         while (found != NULL) {
2630           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2631               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2632             // Check that the bci found is bracketed by terminators.
2633             break;
2634           }
2635           found = strstr(found + 1, buffer);
2636         }
2637         if (!found) {
2638           continue;
2639         }
2640       }
2641 
2642       if (DebugDeoptimization && !deopt) {
2643         deopt = true; // One-time only print before deopt
2644         tty->print_cr("[BEFORE Deoptimization]");
2645         trace_frames();
2646         trace_stack();
2647       }
2648       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2649     }
2650   }
2651 
2652   if (DebugDeoptimization && deopt) {
2653     tty->print_cr("[AFTER Deoptimization]");
2654     trace_frames();
2655   }
2656 }
2657 
2658 
2659 // Make zombies
2660 void JavaThread::make_zombies() {
2661   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2662     if (fst.current()->can_be_deoptimized()) {
2663       // it is a Java nmethod
2664       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2665       nm->make_not_entrant();
2666     }
2667   }
2668 }
2669 #endif // PRODUCT
2670 
2671 
2672 void JavaThread::deoptimized_wrt_marked_nmethods() {
2673   if (!has_last_Java_frame()) return;
2674   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2675   StackFrameStream fst(this, UseBiasedLocking);
2676   for(; !fst.is_done(); fst.next()) {
2677     if (fst.current()->should_be_deoptimized()) {
2678       if (LogCompilation && xtty != NULL) {
2679         nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2680         xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2681                    this->name(), nm != NULL ? nm->compile_id() : -1);
2682       }
2683 
2684       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2685     }
2686   }
2687 }
2688 
2689 
2690 // GC support
2691 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2692 
2693 void JavaThread::gc_epilogue() {
2694   frames_do(frame_gc_epilogue);
2695 }
2696 
2697 
2698 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2699 
2700 void JavaThread::gc_prologue() {
2701   frames_do(frame_gc_prologue);
2702 }
2703 
2704 // If the caller is a NamedThread, then remember, in the current scope,
2705 // the given JavaThread in its _processed_thread field.
2706 class RememberProcessedThread: public StackObj {
2707   NamedThread* _cur_thr;
2708 public:
2709   RememberProcessedThread(JavaThread* jthr) {
2710     Thread* thread = Thread::current();
2711     if (thread->is_Named_thread()) {
2712       _cur_thr = (NamedThread *)thread;
2713       _cur_thr->set_processed_thread(jthr);
2714     } else {
2715       _cur_thr = NULL;
2716     }
2717   }
2718 
2719   ~RememberProcessedThread() {
2720     if (_cur_thr) {
2721       _cur_thr->set_processed_thread(NULL);
2722     }
2723   }
2724 };
2725 
2726 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2727   // Verify that the deferred card marks have been flushed.
2728   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2729 
2730   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2731   // since there may be more than one thread using each ThreadProfiler.
2732 
2733   // Traverse the GCHandles
2734   Thread::oops_do(f, cld_f, cf);
2735 
2736   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2737           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2738 
2739   if (has_last_Java_frame()) {
2740     // Record JavaThread to GC thread
2741     RememberProcessedThread rpt(this);
2742 
2743     // Traverse the privileged stack
2744     if (_privileged_stack_top != NULL) {
2745       _privileged_stack_top->oops_do(f);
2746     }
2747 
2748     // traverse the registered growable array
2749     if (_array_for_gc != NULL) {
2750       for (int index = 0; index < _array_for_gc->length(); index++) {
2751         f->do_oop(_array_for_gc->adr_at(index));
2752       }
2753     }
2754 
2755     // Traverse the monitor chunks
2756     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2757       chunk->oops_do(f);
2758     }
2759 
2760     // Traverse the execution stack
2761     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2762       fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2763     }
2764   }
2765 
2766   // callee_target is never live across a gc point so NULL it here should
2767   // it still contain a methdOop.
2768 
2769   set_callee_target(NULL);
2770 
2771   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2772   // If we have deferred set_locals there might be oops waiting to be
2773   // written
2774   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2775   if (list != NULL) {
2776     for (int i = 0; i < list->length(); i++) {
2777       list->at(i)->oops_do(f);
2778     }
2779   }
2780 
2781   // Traverse instance variables at the end since the GC may be moving things
2782   // around using this function
2783   f->do_oop((oop*) &_threadObj);
2784   f->do_oop((oop*) &_vm_result);
2785   f->do_oop((oop*) &_exception_oop);
2786   f->do_oop((oop*) &_pending_async_exception);
2787 
2788   if (jvmti_thread_state() != NULL) {
2789     jvmti_thread_state()->oops_do(f);
2790   }
2791 }
2792 
2793 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2794   Thread::nmethods_do(cf);  // (super method is a no-op)
2795 
2796   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2797           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2798 
2799   if (has_last_Java_frame()) {
2800     // Traverse the execution stack
2801     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2802       fst.current()->nmethods_do(cf);
2803     }
2804   }
2805 }
2806 
2807 void JavaThread::metadata_do(void f(Metadata*)) {
2808   Thread::metadata_do(f);
2809   if (has_last_Java_frame()) {
2810     // Traverse the execution stack to call f() on the methods in the stack
2811     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2812       fst.current()->metadata_do(f);
2813     }
2814   } else if (is_Compiler_thread()) {
2815     // need to walk ciMetadata in current compile tasks to keep alive.
2816     CompilerThread* ct = (CompilerThread*)this;
2817     if (ct->env() != NULL) {
2818       ct->env()->metadata_do(f);
2819     }
2820   }
2821 }
2822 
2823 // Printing
2824 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2825   switch (_thread_state) {
2826   case _thread_uninitialized:     return "_thread_uninitialized";
2827   case _thread_new:               return "_thread_new";
2828   case _thread_new_trans:         return "_thread_new_trans";
2829   case _thread_in_native:         return "_thread_in_native";
2830   case _thread_in_native_trans:   return "_thread_in_native_trans";
2831   case _thread_in_vm:             return "_thread_in_vm";
2832   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2833   case _thread_in_Java:           return "_thread_in_Java";
2834   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2835   case _thread_blocked:           return "_thread_blocked";
2836   case _thread_blocked_trans:     return "_thread_blocked_trans";
2837   default:                        return "unknown thread state";
2838   }
2839 }
2840 
2841 #ifndef PRODUCT
2842 void JavaThread::print_thread_state_on(outputStream *st) const {
2843   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2844 };
2845 void JavaThread::print_thread_state() const {
2846   print_thread_state_on(tty);
2847 };
2848 #endif // PRODUCT
2849 
2850 // Called by Threads::print() for VM_PrintThreads operation
2851 void JavaThread::print_on(outputStream *st) const {
2852   st->print("\"%s\" ", get_thread_name());
2853   oop thread_oop = threadObj();
2854   if (thread_oop != NULL) {
2855     st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2856     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2857     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2858   }
2859   Thread::print_on(st);
2860   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2861   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2862   if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2863     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2864   }
2865 #ifndef PRODUCT
2866   print_thread_state_on(st);
2867   _safepoint_state->print_on(st);
2868 #endif // PRODUCT
2869 }
2870 
2871 // Called by fatal error handler. The difference between this and
2872 // JavaThread::print() is that we can't grab lock or allocate memory.
2873 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2874   st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
2875   oop thread_obj = threadObj();
2876   if (thread_obj != NULL) {
2877      if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2878   }
2879   st->print(" [");
2880   st->print("%s", _get_thread_state_name(_thread_state));
2881   if (osthread()) {
2882     st->print(", id=%d", osthread()->thread_id());
2883   }
2884   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2885             _stack_base - _stack_size, _stack_base);
2886   st->print("]");
2887   return;
2888 }
2889 
2890 // Verification
2891 
2892 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2893 
2894 void JavaThread::verify() {
2895   // Verify oops in the thread.
2896   oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2897 
2898   // Verify the stack frames.
2899   frames_do(frame_verify);
2900 }
2901 
2902 // CR 6300358 (sub-CR 2137150)
2903 // Most callers of this method assume that it can't return NULL but a
2904 // thread may not have a name whilst it is in the process of attaching to
2905 // the VM - see CR 6412693, and there are places where a JavaThread can be
2906 // seen prior to having it's threadObj set (eg JNI attaching threads and
2907 // if vm exit occurs during initialization). These cases can all be accounted
2908 // for such that this method never returns NULL.
2909 const char* JavaThread::get_thread_name() const {
2910 #ifdef ASSERT
2911   // early safepoints can hit while current thread does not yet have TLS
2912   if (!SafepointSynchronize::is_at_safepoint()) {
2913     Thread *cur = Thread::current();
2914     if (!(cur->is_Java_thread() && cur == this)) {
2915       // Current JavaThreads are allowed to get their own name without
2916       // the Threads_lock.
2917       assert_locked_or_safepoint(Threads_lock);
2918     }
2919   }
2920 #endif // ASSERT
2921     return get_thread_name_string();
2922 }
2923 
2924 // Returns a non-NULL representation of this thread's name, or a suitable
2925 // descriptive string if there is no set name
2926 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2927   const char* name_str;
2928   oop thread_obj = threadObj();
2929   if (thread_obj != NULL) {
2930     oop name = java_lang_Thread::name(thread_obj);
2931     if (name != NULL) {
2932       if (buf == NULL) {
2933         name_str = java_lang_String::as_utf8_string(name);
2934       }
2935       else {
2936         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2937       }
2938     }
2939     else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2940       name_str = "<no-name - thread is attaching>";
2941     }
2942     else {
2943       name_str = Thread::name();
2944     }
2945   }
2946   else {
2947     name_str = Thread::name();
2948   }
2949   assert(name_str != NULL, "unexpected NULL thread name");
2950   return name_str;
2951 }
2952 
2953 
2954 const char* JavaThread::get_threadgroup_name() const {
2955   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2956   oop thread_obj = threadObj();
2957   if (thread_obj != NULL) {
2958     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2959     if (thread_group != NULL) {
2960       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2961       // ThreadGroup.name can be null
2962       if (name != NULL) {
2963         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2964         return str;
2965       }
2966     }
2967   }
2968   return NULL;
2969 }
2970 
2971 const char* JavaThread::get_parent_name() const {
2972   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2973   oop thread_obj = threadObj();
2974   if (thread_obj != NULL) {
2975     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2976     if (thread_group != NULL) {
2977       oop parent = java_lang_ThreadGroup::parent(thread_group);
2978       if (parent != NULL) {
2979         typeArrayOop name = java_lang_ThreadGroup::name(parent);
2980         // ThreadGroup.name can be null
2981         if (name != NULL) {
2982           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2983           return str;
2984         }
2985       }
2986     }
2987   }
2988   return NULL;
2989 }
2990 
2991 ThreadPriority JavaThread::java_priority() const {
2992   oop thr_oop = threadObj();
2993   if (thr_oop == NULL) return NormPriority; // Bootstrapping
2994   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2995   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2996   return priority;
2997 }
2998 
2999 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3000 
3001   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3002   // Link Java Thread object <-> C++ Thread
3003 
3004   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3005   // and put it into a new Handle.  The Handle "thread_oop" can then
3006   // be used to pass the C++ thread object to other methods.
3007 
3008   // Set the Java level thread object (jthread) field of the
3009   // new thread (a JavaThread *) to C++ thread object using the
3010   // "thread_oop" handle.
3011 
3012   // Set the thread field (a JavaThread *) of the
3013   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3014 
3015   Handle thread_oop(Thread::current(),
3016                     JNIHandles::resolve_non_null(jni_thread));
3017   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3018     "must be initialized");
3019   set_threadObj(thread_oop());
3020   java_lang_Thread::set_thread(thread_oop(), this);
3021 
3022   if (prio == NoPriority) {
3023     prio = java_lang_Thread::priority(thread_oop());
3024     assert(prio != NoPriority, "A valid priority should be present");
3025   }
3026 
3027   // Push the Java priority down to the native thread; needs Threads_lock
3028   Thread::set_priority(this, prio);
3029 
3030   prepare_ext();
3031 
3032   // Add the new thread to the Threads list and set it in motion.
3033   // We must have threads lock in order to call Threads::add.
3034   // It is crucial that we do not block before the thread is
3035   // added to the Threads list for if a GC happens, then the java_thread oop
3036   // will not be visited by GC.
3037   Threads::add(this);
3038 }
3039 
3040 oop JavaThread::current_park_blocker() {
3041   // Support for JSR-166 locks
3042   oop thread_oop = threadObj();
3043   if (thread_oop != NULL &&
3044       JDK_Version::current().supports_thread_park_blocker()) {
3045     return java_lang_Thread::park_blocker(thread_oop);
3046   }
3047   return NULL;
3048 }
3049 
3050 
3051 void JavaThread::print_stack_on(outputStream* st) {
3052   if (!has_last_Java_frame()) return;
3053   ResourceMark rm;
3054   HandleMark   hm;
3055 
3056   RegisterMap reg_map(this);
3057   vframe* start_vf = last_java_vframe(&reg_map);
3058   int count = 0;
3059   for (vframe* f = start_vf; f; f = f->sender() ) {
3060     if (f->is_java_frame()) {
3061       javaVFrame* jvf = javaVFrame::cast(f);
3062       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3063 
3064       // Print out lock information
3065       if (JavaMonitorsInStackTrace) {
3066         jvf->print_lock_info_on(st, count);
3067       }
3068     } else {
3069       // Ignore non-Java frames
3070     }
3071 
3072     // Bail-out case for too deep stacks
3073     count++;
3074     if (MaxJavaStackTraceDepth == count) return;
3075   }
3076 }
3077 
3078 
3079 // JVMTI PopFrame support
3080 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3081   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3082   if (in_bytes(size_in_bytes) != 0) {
3083     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3084     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3085     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3086   }
3087 }
3088 
3089 void* JavaThread::popframe_preserved_args() {
3090   return _popframe_preserved_args;
3091 }
3092 
3093 ByteSize JavaThread::popframe_preserved_args_size() {
3094   return in_ByteSize(_popframe_preserved_args_size);
3095 }
3096 
3097 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3098   int sz = in_bytes(popframe_preserved_args_size());
3099   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3100   return in_WordSize(sz / wordSize);
3101 }
3102 
3103 void JavaThread::popframe_free_preserved_args() {
3104   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3105   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3106   _popframe_preserved_args = NULL;
3107   _popframe_preserved_args_size = 0;
3108 }
3109 
3110 #ifndef PRODUCT
3111 
3112 void JavaThread::trace_frames() {
3113   tty->print_cr("[Describe stack]");
3114   int frame_no = 1;
3115   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3116     tty->print("  %d. ", frame_no++);
3117     fst.current()->print_value_on(tty,this);
3118     tty->cr();
3119   }
3120 }
3121 
3122 class PrintAndVerifyOopClosure: public OopClosure {
3123  protected:
3124   template <class T> inline void do_oop_work(T* p) {
3125     oop obj = oopDesc::load_decode_heap_oop(p);
3126     if (obj == NULL) return;
3127     tty->print(INTPTR_FORMAT ": ", p);
3128     if (obj->is_oop_or_null()) {
3129       if (obj->is_objArray()) {
3130         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3131       } else {
3132         obj->print();
3133       }
3134     } else {
3135       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3136     }
3137     tty->cr();
3138   }
3139  public:
3140   virtual void do_oop(oop* p) { do_oop_work(p); }
3141   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3142 };
3143 
3144 
3145 static void oops_print(frame* f, const RegisterMap *map) {
3146   PrintAndVerifyOopClosure print;
3147   f->print_value();
3148   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3149 }
3150 
3151 // Print our all the locations that contain oops and whether they are
3152 // valid or not.  This useful when trying to find the oldest frame
3153 // where an oop has gone bad since the frame walk is from youngest to
3154 // oldest.
3155 void JavaThread::trace_oops() {
3156   tty->print_cr("[Trace oops]");
3157   frames_do(oops_print);
3158 }
3159 
3160 
3161 #ifdef ASSERT
3162 // Print or validate the layout of stack frames
3163 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3164   ResourceMark rm;
3165   PRESERVE_EXCEPTION_MARK;
3166   FrameValues values;
3167   int frame_no = 0;
3168   for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3169     fst.current()->describe(values, ++frame_no);
3170     if (depth == frame_no) break;
3171   }
3172   if (validate_only) {
3173     values.validate();
3174   } else {
3175     tty->print_cr("[Describe stack layout]");
3176     values.print(this);
3177   }
3178 }
3179 #endif
3180 
3181 void JavaThread::trace_stack_from(vframe* start_vf) {
3182   ResourceMark rm;
3183   int vframe_no = 1;
3184   for (vframe* f = start_vf; f; f = f->sender() ) {
3185     if (f->is_java_frame()) {
3186       javaVFrame::cast(f)->print_activation(vframe_no++);
3187     } else {
3188       f->print();
3189     }
3190     if (vframe_no > StackPrintLimit) {
3191       tty->print_cr("...<more frames>...");
3192       return;
3193     }
3194   }
3195 }
3196 
3197 
3198 void JavaThread::trace_stack() {
3199   if (!has_last_Java_frame()) return;
3200   ResourceMark rm;
3201   HandleMark   hm;
3202   RegisterMap reg_map(this);
3203   trace_stack_from(last_java_vframe(&reg_map));
3204 }
3205 
3206 
3207 #endif // PRODUCT
3208 
3209 
3210 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3211   assert(reg_map != NULL, "a map must be given");
3212   frame f = last_frame();
3213   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3214     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3215   }
3216   return NULL;
3217 }
3218 
3219 
3220 Klass* JavaThread::security_get_caller_class(int depth) {
3221   vframeStream vfst(this);
3222   vfst.security_get_caller_frame(depth);
3223   if (!vfst.at_end()) {
3224     return vfst.method()->method_holder();
3225   }
3226   return NULL;
3227 }
3228 
3229 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3230   assert(thread->is_Compiler_thread(), "must be compiler thread");
3231   CompileBroker::compiler_thread_loop();
3232 }
3233 
3234 // Create a CompilerThread
3235 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3236 : JavaThread(&compiler_thread_entry) {
3237   _env   = NULL;
3238   _log   = NULL;
3239   _task  = NULL;
3240   _queue = queue;
3241   _counters = counters;
3242   _buffer_blob = NULL;
3243   _scanned_nmethod = NULL;
3244   _compiler = NULL;
3245 
3246   // Compiler uses resource area for compilation, let's bias it to mtCompiler
3247   resource_area()->bias_to(mtCompiler);
3248 
3249 #ifndef PRODUCT
3250   _ideal_graph_printer = NULL;
3251 #endif
3252 }
3253 
3254 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3255   JavaThread::oops_do(f, cld_f, cf);
3256   if (_scanned_nmethod != NULL && cf != NULL) {
3257     // Safepoints can occur when the sweeper is scanning an nmethod so
3258     // process it here to make sure it isn't unloaded in the middle of
3259     // a scan.
3260     cf->do_code_blob(_scanned_nmethod);
3261   }
3262 }
3263 
3264 
3265 // ======= Threads ========
3266 
3267 // The Threads class links together all active threads, and provides
3268 // operations over all threads.  It is protected by its own Mutex
3269 // lock, which is also used in other contexts to protect thread
3270 // operations from having the thread being operated on from exiting
3271 // and going away unexpectedly (e.g., safepoint synchronization)
3272 
3273 JavaThread* Threads::_thread_list = NULL;
3274 int         Threads::_number_of_threads = 0;
3275 int         Threads::_number_of_non_daemon_threads = 0;
3276 int         Threads::_return_code = 0;
3277 size_t      JavaThread::_stack_size_at_create = 0;
3278 #ifdef ASSERT
3279 bool        Threads::_vm_complete = false;
3280 #endif
3281 
3282 // All JavaThreads
3283 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3284 
3285 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3286 void Threads::threads_do(ThreadClosure* tc) {
3287   assert_locked_or_safepoint(Threads_lock);
3288   // ALL_JAVA_THREADS iterates through all JavaThreads
3289   ALL_JAVA_THREADS(p) {
3290     tc->do_thread(p);
3291   }
3292   // Someday we could have a table or list of all non-JavaThreads.
3293   // For now, just manually iterate through them.
3294   tc->do_thread(VMThread::vm_thread());
3295   Universe::heap()->gc_threads_do(tc);
3296   WatcherThread *wt = WatcherThread::watcher_thread();
3297   // Strictly speaking, the following NULL check isn't sufficient to make sure
3298   // the data for WatcherThread is still valid upon being examined. However,
3299   // considering that WatchThread terminates when the VM is on the way to
3300   // exit at safepoint, the chance of the above is extremely small. The right
3301   // way to prevent termination of WatcherThread would be to acquire
3302   // Terminator_lock, but we can't do that without violating the lock rank
3303   // checking in some cases.
3304   if (wt != NULL)
3305     tc->do_thread(wt);
3306 
3307 #if INCLUDE_JFR
3308   Thread* sampler_thread = Jfr::sampler_thread();
3309   if (sampler_thread != NULL) {
3310     tc->do_thread(sampler_thread);
3311   }
3312 
3313 #endif
3314 
3315   // If CompilerThreads ever become non-JavaThreads, add them here
3316 }
3317 
3318 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3319 
3320   extern void JDK_Version_init();
3321 
3322   // Preinitialize version info.
3323   VM_Version::early_initialize();
3324 
3325   // Check version
3326   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3327 
3328   // Initialize the output stream module
3329   ostream_init();
3330 
3331   // Process java launcher properties.
3332   Arguments::process_sun_java_launcher_properties(args);
3333 
3334   // Initialize the os module before using TLS
3335   os::init();
3336 
3337   // Initialize system properties.
3338   Arguments::init_system_properties();
3339 
3340   // So that JDK version can be used as a discrimintor when parsing arguments
3341   JDK_Version_init();
3342 
3343   // Update/Initialize System properties after JDK version number is known
3344   Arguments::init_version_specific_system_properties();
3345 
3346   // Parse arguments
3347   // Note: this internally calls os::init_container_support()
3348   jint parse_result = Arguments::parse(args);
3349   if (parse_result != JNI_OK) return parse_result;
3350 
3351   os::init_before_ergo();
3352 
3353   jint ergo_result = Arguments::apply_ergo();
3354   if (ergo_result != JNI_OK) return ergo_result;
3355 
3356   if (PauseAtStartup) {
3357     os::pause();
3358   }
3359 
3360 #ifndef USDT2
3361   HS_DTRACE_PROBE(hotspot, vm__init__begin);
3362 #else /* USDT2 */
3363   HOTSPOT_VM_INIT_BEGIN();
3364 #endif /* USDT2 */
3365 
3366   // Record VM creation timing statistics
3367   TraceVmCreationTime create_vm_timer;
3368   create_vm_timer.start();
3369 
3370   // Timing (must come after argument parsing)
3371   TraceTime timer("Create VM", TraceStartupTime);
3372 
3373   // Initialize the os module after parsing the args
3374   jint os_init_2_result = os::init_2();
3375   if (os_init_2_result != JNI_OK) return os_init_2_result;
3376 
3377   jint adjust_after_os_result = Arguments::adjust_after_os();
3378   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3379 
3380   // intialize TLS
3381   ThreadLocalStorage::init();
3382 
3383   // Initialize output stream logging
3384   ostream_init_log();
3385 
3386   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3387   // Must be before create_vm_init_agents()
3388   if (Arguments::init_libraries_at_startup()) {
3389     convert_vm_init_libraries_to_agents();
3390   }
3391 
3392   // Launch -agentlib/-agentpath and converted -Xrun agents
3393   if (Arguments::init_agents_at_startup()) {
3394     create_vm_init_agents();
3395   }
3396 
3397   // Initialize Threads state
3398   _thread_list = NULL;
3399   _number_of_threads = 0;
3400   _number_of_non_daemon_threads = 0;
3401 
3402   // Initialize global data structures and create system classes in heap
3403   vm_init_globals();
3404 
3405   // Attach the main thread to this os thread
3406   JavaThread* main_thread = new JavaThread();
3407   main_thread->set_thread_state(_thread_in_vm);
3408   // must do this before set_active_handles and initialize_thread_local_storage
3409   // Note: on solaris initialize_thread_local_storage() will (indirectly)
3410   // change the stack size recorded here to one based on the java thread
3411   // stacksize. This adjusted size is what is used to figure the placement
3412   // of the guard pages.
3413   main_thread->record_stack_base_and_size();
3414   main_thread->initialize_thread_local_storage();
3415 
3416   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3417 
3418   if (!main_thread->set_as_starting_thread()) {
3419     vm_shutdown_during_initialization(
3420       "Failed necessary internal allocation. Out of swap space");
3421     delete main_thread;
3422     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3423     return JNI_ENOMEM;
3424   }
3425 
3426   // Enable guard page *after* os::create_main_thread(), otherwise it would
3427   // crash Linux VM, see notes in os_linux.cpp.
3428   main_thread->create_stack_guard_pages();
3429 
3430   // Initialize Java-Level synchronization subsystem
3431   ObjectMonitor::Initialize() ;
3432 
3433   // Initialize global modules
3434   jint status = init_globals();
3435   if (status != JNI_OK) {
3436     delete main_thread;
3437     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3438     return status;
3439   }
3440 
3441   JFR_ONLY(Jfr::on_vm_init();)
3442 
3443   // Should be done after the heap is fully created
3444   main_thread->cache_global_variables();
3445 
3446   HandleMark hm;
3447 
3448   { MutexLocker mu(Threads_lock);
3449     Threads::add(main_thread);
3450   }
3451 
3452   // Any JVMTI raw monitors entered in onload will transition into
3453   // real raw monitor. VM is setup enough here for raw monitor enter.
3454   JvmtiExport::transition_pending_onload_raw_monitors();
3455 
3456   // Create the VMThread
3457   { TraceTime timer("Start VMThread", TraceStartupTime);
3458     VMThread::create();
3459     Thread* vmthread = VMThread::vm_thread();
3460 
3461     if (!os::create_thread(vmthread, os::vm_thread))
3462       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3463 
3464     // Wait for the VM thread to become ready, and VMThread::run to initialize
3465     // Monitors can have spurious returns, must always check another state flag
3466     {
3467       MutexLocker ml(Notify_lock);
3468       os::start_thread(vmthread);
3469       while (vmthread->active_handles() == NULL) {
3470         Notify_lock->wait();
3471       }
3472     }
3473   }
3474 
3475   assert (Universe::is_fully_initialized(), "not initialized");
3476   if (VerifyDuringStartup) {
3477     // Make sure we're starting with a clean slate.
3478     VM_Verify verify_op;
3479     VMThread::execute(&verify_op);
3480   }
3481 
3482   EXCEPTION_MARK;
3483 
3484   // At this point, the Universe is initialized, but we have not executed
3485   // any byte code.  Now is a good time (the only time) to dump out the
3486   // internal state of the JVM for sharing.
3487   if (DumpSharedSpaces) {
3488     MetaspaceShared::preload_and_dump(CHECK_0);
3489     ShouldNotReachHere();
3490   }
3491 
3492   // Always call even when there are not JVMTI environments yet, since environments
3493   // may be attached late and JVMTI must track phases of VM execution
3494   JvmtiExport::enter_start_phase();
3495 
3496   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3497   JvmtiExport::post_vm_start();
3498 
3499   {
3500     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3501 
3502     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3503       create_vm_init_libraries();
3504     }
3505 
3506     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3507 
3508     // Initialize java_lang.System (needed before creating the thread)
3509     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3510     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3511     Handle thread_group = create_initial_thread_group(CHECK_0);
3512     Universe::set_main_thread_group(thread_group());
3513     initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3514     oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3515     main_thread->set_threadObj(thread_object);
3516     // Set thread status to running since main thread has
3517     // been started and running.
3518     java_lang_Thread::set_thread_status(thread_object,
3519                                         java_lang_Thread::RUNNABLE);
3520 
3521     // The VM creates & returns objects of this class. Make sure it's initialized.
3522     initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3523 
3524     // The VM preresolves methods to these classes. Make sure that they get initialized
3525     initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3526     initialize_class(vmSymbols::java_lang_ref_Finalizer(),  CHECK_0);
3527     call_initializeSystemClass(CHECK_0);
3528 
3529     // get the Java runtime name after java.lang.System is initialized
3530     JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3531     JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3532 
3533     // an instance of OutOfMemory exception has been allocated earlier
3534     initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3535     initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3536     initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3537     initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3538     initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3539     initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3540     initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3541     initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3542   }
3543 
3544   // See        : bugid 4211085.
3545   // Background : the static initializer of java.lang.Compiler tries to read
3546   //              property"java.compiler" and read & write property "java.vm.info".
3547   //              When a security manager is installed through the command line
3548   //              option "-Djava.security.manager", the above properties are not
3549   //              readable and the static initializer for java.lang.Compiler fails
3550   //              resulting in a NoClassDefFoundError.  This can happen in any
3551   //              user code which calls methods in java.lang.Compiler.
3552   // Hack :       the hack is to pre-load and initialize this class, so that only
3553   //              system domains are on the stack when the properties are read.
3554   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3555   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3556   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3557   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3558   //              Once that is done, we should remove this hack.
3559   initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3560 
3561   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3562   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3563   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3564   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3565   // This should also be taken out as soon as 4211383 gets fixed.
3566   reset_vm_info_property(CHECK_0);
3567 
3568   quicken_jni_functions();
3569 
3570   // Set flag that basic initialization has completed. Used by exceptions and various
3571   // debug stuff, that does not work until all basic classes have been initialized.
3572   set_init_completed();
3573 
3574   Metaspace::post_initialize();
3575 
3576 #ifndef USDT2
3577   HS_DTRACE_PROBE(hotspot, vm__init__end);
3578 #else /* USDT2 */
3579   HOTSPOT_VM_INIT_END();
3580 #endif /* USDT2 */
3581 
3582   // record VM initialization completion time
3583 #if INCLUDE_MANAGEMENT
3584   Management::record_vm_init_completed();
3585 #endif // INCLUDE_MANAGEMENT
3586 
3587   // Compute system loader. Note that this has to occur after set_init_completed, since
3588   // valid exceptions may be thrown in the process.
3589   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3590   // set_init_completed has just been called, causing exceptions not to be shortcut
3591   // anymore. We call vm_exit_during_initialization directly instead.
3592   SystemDictionary::compute_java_system_loader(THREAD);
3593   if (HAS_PENDING_EXCEPTION) {
3594     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3595   }
3596 
3597 #if INCLUDE_ALL_GCS
3598   // Support for ConcurrentMarkSweep. This should be cleaned up
3599   // and better encapsulated. The ugly nested if test would go away
3600   // once things are properly refactored. XXX YSR
3601   if (UseConcMarkSweepGC || UseG1GC) {
3602     if (UseConcMarkSweepGC) {
3603       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3604     } else {
3605       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3606     }
3607     if (HAS_PENDING_EXCEPTION) {
3608       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3609     }
3610   }
3611 #endif // INCLUDE_ALL_GCS
3612 
3613   // Always call even when there are not JVMTI environments yet, since environments
3614   // may be attached late and JVMTI must track phases of VM execution
3615   JvmtiExport::enter_live_phase();
3616 
3617   // Signal Dispatcher needs to be started before VMInit event is posted
3618   os::signal_init();
3619 
3620   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3621   if (!DisableAttachMechanism) {
3622     AttachListener::vm_start();
3623     if (StartAttachListener || AttachListener::init_at_startup()) {
3624       AttachListener::init();
3625     }
3626   }
3627 
3628   // Launch -Xrun agents
3629   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3630   // back-end can launch with -Xdebug -Xrunjdwp.
3631   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3632     create_vm_init_libraries();
3633   }
3634 
3635   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3636   JvmtiExport::post_vm_initialized();
3637 
3638   JFR_ONLY(Jfr::on_vm_start();)
3639 
3640   if (CleanChunkPoolAsync) {
3641     Chunk::start_chunk_pool_cleaner_task();
3642   }
3643 
3644   // initialize compiler(s)
3645 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3646   CompileBroker::compilation_init();
3647 #endif
3648 
3649   if (EnableInvokeDynamic) {
3650     // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3651     // It is done after compilers are initialized, because otherwise compilations of
3652     // signature polymorphic MH intrinsics can be missed
3653     // (see SystemDictionary::find_method_handle_intrinsic).
3654     initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3655     initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3656     initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3657   }
3658 
3659 #if INCLUDE_MANAGEMENT
3660   Management::initialize(THREAD);
3661 #endif // INCLUDE_MANAGEMENT
3662 
3663   if (HAS_PENDING_EXCEPTION) {
3664     // management agent fails to start possibly due to
3665     // configuration problem and is responsible for printing
3666     // stack trace if appropriate. Simply exit VM.
3667     vm_exit(1);
3668   }
3669 
3670   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3671   if (MemProfiling)                   MemProfiler::engage();
3672   StatSampler::engage();
3673   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3674 
3675   BiasedLocking::init();
3676 
3677 #if INCLUDE_RTM_OPT
3678   RTMLockingCounters::init();
3679 #endif
3680 
3681   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3682     call_postVMInitHook(THREAD);
3683     // The Java side of PostVMInitHook.run must deal with all
3684     // exceptions and provide means of diagnosis.
3685     if (HAS_PENDING_EXCEPTION) {
3686       CLEAR_PENDING_EXCEPTION;
3687     }
3688   }
3689 
3690   {
3691       MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3692       // Make sure the watcher thread can be started by WatcherThread::start()
3693       // or by dynamic enrollment.
3694       WatcherThread::make_startable();
3695       // Start up the WatcherThread if there are any periodic tasks
3696       // NOTE:  All PeriodicTasks should be registered by now. If they
3697       //   aren't, late joiners might appear to start slowly (we might
3698       //   take a while to process their first tick).
3699       if (PeriodicTask::num_tasks() > 0) {
3700           WatcherThread::start();
3701       }
3702   }
3703 
3704   create_vm_timer.end();
3705 #ifdef ASSERT
3706   _vm_complete = true;
3707 #endif
3708   return JNI_OK;
3709 }
3710 
3711 // type for the Agent_OnLoad and JVM_OnLoad entry points
3712 extern "C" {
3713   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3714 }
3715 // Find a command line agent library and return its entry point for
3716 //         -agentlib:  -agentpath:   -Xrun
3717 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3718 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3719   OnLoadEntry_t on_load_entry = NULL;
3720   void *library = NULL;
3721 
3722   if (!agent->valid()) {
3723     char buffer[JVM_MAXPATHLEN];
3724     char ebuf[1024];
3725     const char *name = agent->name();
3726     const char *msg = "Could not find agent library ";
3727 
3728     // First check to see if agent is statically linked into executable
3729     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3730       library = agent->os_lib();
3731     } else if (agent->is_absolute_path()) {
3732       library = os::dll_load(name, ebuf, sizeof ebuf);
3733       if (library == NULL) {
3734         const char *sub_msg = " in absolute path, with error: ";
3735         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3736         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3737         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3738         // If we can't find the agent, exit.
3739         vm_exit_during_initialization(buf, NULL);
3740         FREE_C_HEAP_ARRAY(char, buf, mtThread);
3741       }
3742     } else {
3743       // Try to load the agent from the standard dll directory
3744       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3745                              name)) {
3746         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3747       }
3748       if (library == NULL) { // Try the local directory
3749         char ns[1] = {0};
3750         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3751           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3752         }
3753         if (library == NULL) {
3754           const char *sub_msg = " on the library path, with error: ";
3755           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3756           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3757           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3758           // If we can't find the agent, exit.
3759           vm_exit_during_initialization(buf, NULL);
3760           FREE_C_HEAP_ARRAY(char, buf, mtThread);
3761         }
3762       }
3763     }
3764     agent->set_os_lib(library);
3765     agent->set_valid();
3766   }
3767 
3768   // Find the OnLoad function.
3769   on_load_entry =
3770     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3771                                                           false,
3772                                                           on_load_symbols,
3773                                                           num_symbol_entries));
3774   return on_load_entry;
3775 }
3776 
3777 // Find the JVM_OnLoad entry point
3778 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3779   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3780   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3781 }
3782 
3783 // Find the Agent_OnLoad entry point
3784 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3785   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3786   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3787 }
3788 
3789 // For backwards compatibility with -Xrun
3790 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3791 // treated like -agentpath:
3792 // Must be called before agent libraries are created
3793 void Threads::convert_vm_init_libraries_to_agents() {
3794   AgentLibrary* agent;
3795   AgentLibrary* next;
3796 
3797   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3798     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3799     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3800 
3801     // If there is an JVM_OnLoad function it will get called later,
3802     // otherwise see if there is an Agent_OnLoad
3803     if (on_load_entry == NULL) {
3804       on_load_entry = lookup_agent_on_load(agent);
3805       if (on_load_entry != NULL) {
3806         // switch it to the agent list -- so that Agent_OnLoad will be called,
3807         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3808         Arguments::convert_library_to_agent(agent);
3809       } else {
3810         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3811       }
3812     }
3813   }
3814 }
3815 
3816 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3817 // Invokes Agent_OnLoad
3818 // Called very early -- before JavaThreads exist
3819 void Threads::create_vm_init_agents() {
3820   extern struct JavaVM_ main_vm;
3821   AgentLibrary* agent;
3822 
3823   JvmtiExport::enter_onload_phase();
3824 
3825   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3826     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3827 
3828     if (on_load_entry != NULL) {
3829       // Invoke the Agent_OnLoad function
3830       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3831       if (err != JNI_OK) {
3832         vm_exit_during_initialization("agent library failed to init", agent->name());
3833       }
3834     } else {
3835       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3836     }
3837   }
3838   JvmtiExport::enter_primordial_phase();
3839 }
3840 
3841 extern "C" {
3842   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3843 }
3844 
3845 void Threads::shutdown_vm_agents() {
3846   // Send any Agent_OnUnload notifications
3847   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3848   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3849   extern struct JavaVM_ main_vm;
3850   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3851 
3852     // Find the Agent_OnUnload function.
3853     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3854       os::find_agent_function(agent,
3855       false,
3856       on_unload_symbols,
3857       num_symbol_entries));
3858 
3859     // Invoke the Agent_OnUnload function
3860     if (unload_entry != NULL) {
3861       JavaThread* thread = JavaThread::current();
3862       ThreadToNativeFromVM ttn(thread);
3863       HandleMark hm(thread);
3864       (*unload_entry)(&main_vm);
3865     }
3866   }
3867 }
3868 
3869 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3870 // Invokes JVM_OnLoad
3871 void Threads::create_vm_init_libraries() {
3872   extern struct JavaVM_ main_vm;
3873   AgentLibrary* agent;
3874 
3875   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3876     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3877 
3878     if (on_load_entry != NULL) {
3879       // Invoke the JVM_OnLoad function
3880       JavaThread* thread = JavaThread::current();
3881       ThreadToNativeFromVM ttn(thread);
3882       HandleMark hm(thread);
3883       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3884       if (err != JNI_OK) {
3885         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3886       }
3887     } else {
3888       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3889     }
3890   }
3891 }
3892 
3893 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3894   assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3895 
3896   JavaThread* java_thread = NULL;
3897   // Sequential search for now.  Need to do better optimization later.
3898   for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3899     oop tobj = thread->threadObj();
3900     if (!thread->is_exiting() &&
3901         tobj != NULL &&
3902         java_tid == java_lang_Thread::thread_id(tobj)) {
3903       java_thread = thread;
3904       break;
3905     }
3906   }
3907   return java_thread;
3908 }
3909 
3910 
3911 // Last thread running calls java.lang.Shutdown.shutdown()
3912 void JavaThread::invoke_shutdown_hooks() {
3913   HandleMark hm(this);
3914 
3915   // We could get here with a pending exception, if so clear it now.
3916   if (this->has_pending_exception()) {
3917     this->clear_pending_exception();
3918   }
3919 
3920   EXCEPTION_MARK;
3921   Klass* k =
3922     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3923                                       THREAD);
3924   if (k != NULL) {
3925     // SystemDictionary::resolve_or_null will return null if there was
3926     // an exception.  If we cannot load the Shutdown class, just don't
3927     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3928     // and finalizers (if runFinalizersOnExit is set) won't be run.
3929     // Note that if a shutdown hook was registered or runFinalizersOnExit
3930     // was called, the Shutdown class would have already been loaded
3931     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3932     instanceKlassHandle shutdown_klass (THREAD, k);
3933     JavaValue result(T_VOID);
3934     JavaCalls::call_static(&result,
3935                            shutdown_klass,
3936                            vmSymbols::shutdown_method_name(),
3937                            vmSymbols::void_method_signature(),
3938                            THREAD);
3939   }
3940   CLEAR_PENDING_EXCEPTION;
3941 }
3942 
3943 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3944 // the program falls off the end of main(). Another VM exit path is through
3945 // vm_exit() when the program calls System.exit() to return a value or when
3946 // there is a serious error in VM. The two shutdown paths are not exactly
3947 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3948 // and VM_Exit op at VM level.
3949 //
3950 // Shutdown sequence:
3951 //   + Shutdown native memory tracking if it is on
3952 //   + Wait until we are the last non-daemon thread to execute
3953 //     <-- every thing is still working at this moment -->
3954 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3955 //        shutdown hooks, run finalizers if finalization-on-exit
3956 //   + Call before_exit(), prepare for VM exit
3957 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3958 //        currently the only user of this mechanism is File.deleteOnExit())
3959 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3960 //        post thread end and vm death events to JVMTI,
3961 //        stop signal thread
3962 //   + Call JavaThread::exit(), it will:
3963 //      > release JNI handle blocks, remove stack guard pages
3964 //      > remove this thread from Threads list
3965 //     <-- no more Java code from this thread after this point -->
3966 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3967 //     the compiler threads at safepoint
3968 //     <-- do not use anything that could get blocked by Safepoint -->
3969 //   + Disable tracing at JNI/JVM barriers
3970 //   + Set _vm_exited flag for threads that are still running native code
3971 //   + Delete this thread
3972 //   + Call exit_globals()
3973 //      > deletes tty
3974 //      > deletes PerfMemory resources
3975 //   + Return to caller
3976 
3977 bool Threads::destroy_vm() {
3978   JavaThread* thread = JavaThread::current();
3979 
3980 #ifdef ASSERT
3981   _vm_complete = false;
3982 #endif
3983   // Wait until we are the last non-daemon thread to execute
3984   { MutexLocker nu(Threads_lock);
3985     while (Threads::number_of_non_daemon_threads() > 1 )
3986       // This wait should make safepoint checks, wait without a timeout,
3987       // and wait as a suspend-equivalent condition.
3988       //
3989       // Note: If the FlatProfiler is running and this thread is waiting
3990       // for another non-daemon thread to finish, then the FlatProfiler
3991       // is waiting for the external suspend request on this thread to
3992       // complete. wait_for_ext_suspend_completion() will eventually
3993       // timeout, but that takes time. Making this wait a suspend-
3994       // equivalent condition solves that timeout problem.
3995       //
3996       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3997                          Mutex::_as_suspend_equivalent_flag);
3998   }
3999 
4000   EventShutdown e;
4001   if (e.should_commit()) {
4002     e.set_reason("No remaining non-daemon Java threads");
4003     e.commit();
4004   }
4005 
4006   // Hang forever on exit if we are reporting an error.
4007   if (ShowMessageBoxOnError && is_error_reported()) {
4008     os::infinite_sleep();
4009   }
4010   os::wait_for_keypress_at_exit();
4011 
4012   if (JDK_Version::is_jdk12x_version()) {
4013     // We are the last thread running, so check if finalizers should be run.
4014     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4015     HandleMark rm(thread);
4016     Universe::run_finalizers_on_exit();
4017   } else {
4018     // run Java level shutdown hooks
4019     thread->invoke_shutdown_hooks();
4020   }
4021 
4022   before_exit(thread);
4023 
4024   thread->exit(true);
4025 
4026   // Stop VM thread.
4027   {
4028     // 4945125 The vm thread comes to a safepoint during exit.
4029     // GC vm_operations can get caught at the safepoint, and the
4030     // heap is unparseable if they are caught. Grab the Heap_lock
4031     // to prevent this. The GC vm_operations will not be able to
4032     // queue until after the vm thread is dead. After this point,
4033     // we'll never emerge out of the safepoint before the VM exits.
4034 
4035     MutexLocker ml(Heap_lock);
4036 
4037     VMThread::wait_for_vm_thread_exit();
4038     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4039     VMThread::destroy();
4040   }
4041 
4042   // clean up ideal graph printers
4043 #if defined(COMPILER2) && !defined(PRODUCT)
4044   IdealGraphPrinter::clean_up();
4045 #endif
4046 
4047   // Now, all Java threads are gone except daemon threads. Daemon threads
4048   // running Java code or in VM are stopped by the Safepoint. However,
4049   // daemon threads executing native code are still running.  But they
4050   // will be stopped at native=>Java/VM barriers. Note that we can't
4051   // simply kill or suspend them, as it is inherently deadlock-prone.
4052 
4053 #ifndef PRODUCT
4054   // disable function tracing at JNI/JVM barriers
4055   TraceJNICalls = false;
4056   TraceJVMCalls = false;
4057   TraceRuntimeCalls = false;
4058 #endif
4059 
4060   VM_Exit::set_vm_exited();
4061 
4062   notify_vm_shutdown();
4063 
4064   delete thread;
4065 
4066   // exit_globals() will delete tty
4067   exit_globals();
4068 
4069   return true;
4070 }
4071 
4072 
4073 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4074   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4075   return is_supported_jni_version(version);
4076 }
4077 
4078 
4079 jboolean Threads::is_supported_jni_version(jint version) {
4080   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4081   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4082   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4083   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4084   return JNI_FALSE;
4085 }
4086 
4087 
4088 void Threads::add(JavaThread* p, bool force_daemon) {
4089   // The threads lock must be owned at this point
4090   assert_locked_or_safepoint(Threads_lock);
4091 
4092   // See the comment for this method in thread.hpp for its purpose and
4093   // why it is called here.
4094   p->initialize_queues();
4095   p->set_next(_thread_list);
4096   _thread_list = p;
4097   _number_of_threads++;
4098   oop threadObj = p->threadObj();
4099   bool daemon = true;
4100   // Bootstrapping problem: threadObj can be null for initial
4101   // JavaThread (or for threads attached via JNI)
4102   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4103     _number_of_non_daemon_threads++;
4104     daemon = false;
4105   }
4106 
4107   ThreadService::add_thread(p, daemon);
4108 
4109   // Possible GC point.
4110   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4111 }
4112 
4113 void Threads::remove(JavaThread* p) {
4114   // Extra scope needed for Thread_lock, so we can check
4115   // that we do not remove thread without safepoint code notice
4116   { MutexLocker ml(Threads_lock);
4117 
4118     assert(includes(p), "p must be present");
4119 
4120     JavaThread* current = _thread_list;
4121     JavaThread* prev    = NULL;
4122 
4123     while (current != p) {
4124       prev    = current;
4125       current = current->next();
4126     }
4127 
4128     if (prev) {
4129       prev->set_next(current->next());
4130     } else {
4131       _thread_list = p->next();
4132     }
4133     _number_of_threads--;
4134     oop threadObj = p->threadObj();
4135     bool daemon = true;
4136     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4137       _number_of_non_daemon_threads--;
4138       daemon = false;
4139 
4140       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4141       // on destroy_vm will wake up.
4142       if (number_of_non_daemon_threads() == 1)
4143         Threads_lock->notify_all();
4144     }
4145     ThreadService::remove_thread(p, daemon);
4146 
4147     // Make sure that safepoint code disregard this thread. This is needed since
4148     // the thread might mess around with locks after this point. This can cause it
4149     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4150     // of this thread since it is removed from the queue.
4151     p->set_terminated_value();
4152   } // unlock Threads_lock
4153 
4154   // Since Events::log uses a lock, we grab it outside the Threads_lock
4155   Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4156 }
4157 
4158 // Threads_lock must be held when this is called (or must be called during a safepoint)
4159 bool Threads::includes(JavaThread* p) {
4160   assert(Threads_lock->is_locked(), "sanity check");
4161   ALL_JAVA_THREADS(q) {
4162     if (q == p ) {
4163       return true;
4164     }
4165   }
4166   return false;
4167 }
4168 
4169 // Operations on the Threads list for GC.  These are not explicitly locked,
4170 // but the garbage collector must provide a safe context for them to run.
4171 // In particular, these things should never be called when the Threads_lock
4172 // is held by some other thread. (Note: the Safepoint abstraction also
4173 // uses the Threads_lock to gurantee this property. It also makes sure that
4174 // all threads gets blocked when exiting or starting).
4175 
4176 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4177   ALL_JAVA_THREADS(p) {
4178     p->oops_do(f, cld_f, cf);
4179   }
4180   VMThread::vm_thread()->oops_do(f, cld_f, cf);
4181 }
4182 
4183 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4184   // Introduce a mechanism allowing parallel threads to claim threads as
4185   // root groups.  Overhead should be small enough to use all the time,
4186   // even in sequential code.
4187   SharedHeap* sh = SharedHeap::heap();
4188   // Cannot yet substitute active_workers for n_par_threads
4189   // because of G1CollectedHeap::verify() use of
4190   // SharedHeap::process_roots().  n_par_threads == 0 will
4191   // turn off parallelism in process_roots while active_workers
4192   // is being used for parallelism elsewhere.
4193   bool is_par = sh->n_par_threads() > 0;
4194   assert(!is_par ||
4195          (SharedHeap::heap()->n_par_threads() ==
4196           SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4197   int cp = SharedHeap::heap()->strong_roots_parity();
4198   ALL_JAVA_THREADS(p) {
4199     if (p->claim_oops_do(is_par, cp)) {
4200       p->oops_do(f, cld_f, cf);
4201     }
4202   }
4203   VMThread* vmt = VMThread::vm_thread();
4204   if (vmt->claim_oops_do(is_par, cp)) {
4205     vmt->oops_do(f, cld_f, cf);
4206   }
4207 }
4208 
4209 #if INCLUDE_ALL_GCS
4210 // Used by ParallelScavenge
4211 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4212   ALL_JAVA_THREADS(p) {
4213     q->enqueue(new ThreadRootsTask(p));
4214   }
4215   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4216 }
4217 
4218 // Used by Parallel Old
4219 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4220   ALL_JAVA_THREADS(p) {
4221     q->enqueue(new ThreadRootsMarkingTask(p));
4222   }
4223   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4224 }
4225 #endif // INCLUDE_ALL_GCS
4226 
4227 void Threads::nmethods_do(CodeBlobClosure* cf) {
4228   ALL_JAVA_THREADS(p) {
4229     p->nmethods_do(cf);
4230   }
4231   VMThread::vm_thread()->nmethods_do(cf);
4232 }
4233 
4234 void Threads::metadata_do(void f(Metadata*)) {
4235   ALL_JAVA_THREADS(p) {
4236     p->metadata_do(f);
4237   }
4238 }
4239 
4240 void Threads::gc_epilogue() {
4241   ALL_JAVA_THREADS(p) {
4242     p->gc_epilogue();
4243   }
4244 }
4245 
4246 void Threads::gc_prologue() {
4247   ALL_JAVA_THREADS(p) {
4248     p->gc_prologue();
4249   }
4250 }
4251 
4252 void Threads::deoptimized_wrt_marked_nmethods() {
4253   ALL_JAVA_THREADS(p) {
4254     p->deoptimized_wrt_marked_nmethods();
4255   }
4256 }
4257 
4258 
4259 // Get count Java threads that are waiting to enter the specified monitor.
4260 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4261   address monitor, bool doLock) {
4262   assert(doLock || SafepointSynchronize::is_at_safepoint(),
4263     "must grab Threads_lock or be at safepoint");
4264   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4265 
4266   int i = 0;
4267   {
4268     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4269     ALL_JAVA_THREADS(p) {
4270       if (p->is_Compiler_thread()) continue;
4271 
4272       address pending = (address)p->current_pending_monitor();
4273       if (pending == monitor) {             // found a match
4274         if (i < count) result->append(p);   // save the first count matches
4275         i++;
4276       }
4277     }
4278   }
4279   return result;
4280 }
4281 
4282 
4283 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4284   assert(doLock ||
4285          Threads_lock->owned_by_self() ||
4286          SafepointSynchronize::is_at_safepoint(),
4287          "must grab Threads_lock or be at safepoint");
4288 
4289   // NULL owner means not locked so we can skip the search
4290   if (owner == NULL) return NULL;
4291 
4292   {
4293     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4294     ALL_JAVA_THREADS(p) {
4295       // first, see if owner is the address of a Java thread
4296       if (owner == (address)p) return p;
4297     }
4298   }
4299   // Cannot assert on lack of success here since this function may be
4300   // used by code that is trying to report useful problem information
4301   // like deadlock detection.
4302   if (UseHeavyMonitors) return NULL;
4303 
4304   //
4305   // If we didn't find a matching Java thread and we didn't force use of
4306   // heavyweight monitors, then the owner is the stack address of the
4307   // Lock Word in the owning Java thread's stack.
4308   //
4309   JavaThread* the_owner = NULL;
4310   {
4311     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4312     ALL_JAVA_THREADS(q) {
4313       if (q->is_lock_owned(owner)) {
4314         the_owner = q;
4315         break;
4316       }
4317     }
4318   }
4319   // cannot assert on lack of success here; see above comment
4320   return the_owner;
4321 }
4322 
4323 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4324 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4325   char buf[32];
4326   st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4327 
4328   st->print_cr("Full thread dump %s (%s %s):",
4329                 Abstract_VM_Version::vm_name(),
4330                 Abstract_VM_Version::vm_release(),
4331                 Abstract_VM_Version::vm_info_string()
4332                );
4333   st->cr();
4334 
4335 #if INCLUDE_ALL_GCS
4336   // Dump concurrent locks
4337   ConcurrentLocksDump concurrent_locks;
4338   if (print_concurrent_locks) {
4339     concurrent_locks.dump_at_safepoint();
4340   }
4341 #endif // INCLUDE_ALL_GCS
4342 
4343   ALL_JAVA_THREADS(p) {
4344     ResourceMark rm;
4345     p->print_on(st);
4346     if (print_stacks) {
4347       if (internal_format) {
4348         p->trace_stack();
4349       } else {
4350         p->print_stack_on(st);
4351       }
4352     }
4353     st->cr();
4354 #if INCLUDE_ALL_GCS
4355     if (print_concurrent_locks) {
4356       concurrent_locks.print_locks_on(p, st);
4357     }
4358 #endif // INCLUDE_ALL_GCS
4359   }
4360 
4361   VMThread::vm_thread()->print_on(st);
4362   st->cr();
4363   Universe::heap()->print_gc_threads_on(st);
4364   WatcherThread* wt = WatcherThread::watcher_thread();
4365   if (wt != NULL) {
4366     wt->print_on(st);
4367     st->cr();
4368   }
4369   CompileBroker::print_compiler_threads_on(st);
4370   st->flush();
4371 }
4372 
4373 // Threads::print_on_error() is called by fatal error handler. It's possible
4374 // that VM is not at safepoint and/or current thread is inside signal handler.
4375 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4376 // memory (even in resource area), it might deadlock the error handler.
4377 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4378   bool found_current = false;
4379   st->print_cr("Java Threads: ( => current thread )");
4380   ALL_JAVA_THREADS(thread) {
4381     bool is_current = (current == thread);
4382     found_current = found_current || is_current;
4383 
4384     st->print("%s", is_current ? "=>" : "  ");
4385 
4386     st->print(PTR_FORMAT, thread);
4387     st->print(" ");
4388     thread->print_on_error(st, buf, buflen);
4389     st->cr();
4390   }
4391   st->cr();
4392 
4393   st->print_cr("Other Threads:");
4394   if (VMThread::vm_thread()) {
4395     bool is_current = (current == VMThread::vm_thread());
4396     found_current = found_current || is_current;
4397     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
4398 
4399     st->print(PTR_FORMAT, VMThread::vm_thread());
4400     st->print(" ");
4401     VMThread::vm_thread()->print_on_error(st, buf, buflen);
4402     st->cr();
4403   }
4404   WatcherThread* wt = WatcherThread::watcher_thread();
4405   if (wt != NULL) {
4406     bool is_current = (current == wt);
4407     found_current = found_current || is_current;
4408     st->print("%s", is_current ? "=>" : "  ");
4409 
4410     st->print(PTR_FORMAT, wt);
4411     st->print(" ");
4412     wt->print_on_error(st, buf, buflen);
4413     st->cr();
4414   }
4415   if (!found_current) {
4416     st->cr();
4417     st->print("=>" PTR_FORMAT " (exited) ", current);
4418     current->print_on_error(st, buf, buflen);
4419     st->cr();
4420   }
4421 }
4422 
4423 // Internal SpinLock and Mutex
4424 // Based on ParkEvent
4425 
4426 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4427 //
4428 // We employ SpinLocks _only for low-contention, fixed-length
4429 // short-duration critical sections where we're concerned
4430 // about native mutex_t or HotSpot Mutex:: latency.
4431 // The mux construct provides a spin-then-block mutual exclusion
4432 // mechanism.
4433 //
4434 // Testing has shown that contention on the ListLock guarding gFreeList
4435 // is common.  If we implement ListLock as a simple SpinLock it's common
4436 // for the JVM to devolve to yielding with little progress.  This is true
4437 // despite the fact that the critical sections protected by ListLock are
4438 // extremely short.
4439 //
4440 // TODO-FIXME: ListLock should be of type SpinLock.
4441 // We should make this a 1st-class type, integrated into the lock
4442 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4443 // should have sufficient padding to avoid false-sharing and excessive
4444 // cache-coherency traffic.
4445 
4446 
4447 typedef volatile int SpinLockT ;
4448 
4449 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4450   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4451      return ;   // normal fast-path return
4452   }
4453 
4454   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4455   TEVENT (SpinAcquire - ctx) ;
4456   int ctr = 0 ;
4457   int Yields = 0 ;
4458   for (;;) {
4459      while (*adr != 0) {
4460         ++ctr ;
4461         if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4462            if (Yields > 5) {
4463              os::naked_short_sleep(1);
4464            } else {
4465              os::NakedYield() ;
4466              ++Yields ;
4467            }
4468         } else {
4469            SpinPause() ;
4470         }
4471      }
4472      if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4473   }
4474 }
4475 
4476 void Thread::SpinRelease (volatile int * adr) {
4477   assert (*adr != 0, "invariant") ;
4478   OrderAccess::fence() ;      // guarantee at least release consistency.
4479   // Roach-motel semantics.
4480   // It's safe if subsequent LDs and STs float "up" into the critical section,
4481   // but prior LDs and STs within the critical section can't be allowed
4482   // to reorder or float past the ST that releases the lock.
4483   *adr = 0 ;
4484 }
4485 
4486 // muxAcquire and muxRelease:
4487 //
4488 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4489 //    The LSB of the word is set IFF the lock is held.
4490 //    The remainder of the word points to the head of a singly-linked list
4491 //    of threads blocked on the lock.
4492 //
4493 // *  The current implementation of muxAcquire-muxRelease uses its own
4494 //    dedicated Thread._MuxEvent instance.  If we're interested in
4495 //    minimizing the peak number of extant ParkEvent instances then
4496 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4497 //    as certain invariants were satisfied.  Specifically, care would need
4498 //    to be taken with regards to consuming unpark() "permits".
4499 //    A safe rule of thumb is that a thread would never call muxAcquire()
4500 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4501 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4502 //    consume an unpark() permit intended for monitorenter, for instance.
4503 //    One way around this would be to widen the restricted-range semaphore
4504 //    implemented in park().  Another alternative would be to provide
4505 //    multiple instances of the PlatformEvent() for each thread.  One
4506 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4507 //
4508 // *  Usage:
4509 //    -- Only as leaf locks
4510 //    -- for short-term locking only as muxAcquire does not perform
4511 //       thread state transitions.
4512 //
4513 // Alternatives:
4514 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4515 //    but with parking or spin-then-park instead of pure spinning.
4516 // *  Use Taura-Oyama-Yonenzawa locks.
4517 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4518 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4519 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4520 //    acquiring threads use timers (ParkTimed) to detect and recover from
4521 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4522 //    boundaries by using placement-new.
4523 // *  Augment MCS with advisory back-link fields maintained with CAS().
4524 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4525 //    The validity of the backlinks must be ratified before we trust the value.
4526 //    If the backlinks are invalid the exiting thread must back-track through the
4527 //    the forward links, which are always trustworthy.
4528 // *  Add a successor indication.  The LockWord is currently encoded as
4529 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4530 //    to provide the usual futile-wakeup optimization.
4531 //    See RTStt for details.
4532 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4533 //
4534 
4535 
4536 typedef volatile intptr_t MutexT ;      // Mux Lock-word
4537 enum MuxBits { LOCKBIT = 1 } ;
4538 
4539 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4540   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4541   if (w == 0) return ;
4542   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4543      return ;
4544   }
4545 
4546   TEVENT (muxAcquire - Contention) ;
4547   ParkEvent * const Self = Thread::current()->_MuxEvent ;
4548   assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4549   for (;;) {
4550      int its = (os::is_MP() ? 100 : 0) + 1 ;
4551 
4552      // Optional spin phase: spin-then-park strategy
4553      while (--its >= 0) {
4554        w = *Lock ;
4555        if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4556           return ;
4557        }
4558      }
4559 
4560      Self->reset() ;
4561      Self->OnList = intptr_t(Lock) ;
4562      // The following fence() isn't _strictly necessary as the subsequent
4563      // CAS() both serializes execution and ratifies the fetched *Lock value.
4564      OrderAccess::fence();
4565      for (;;) {
4566         w = *Lock ;
4567         if ((w & LOCKBIT) == 0) {
4568             if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4569                 Self->OnList = 0 ;   // hygiene - allows stronger asserts
4570                 return ;
4571             }
4572             continue ;      // Interference -- *Lock changed -- Just retry
4573         }
4574         assert (w & LOCKBIT, "invariant") ;
4575         Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4576         if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4577      }
4578 
4579      while (Self->OnList != 0) {
4580         Self->park() ;
4581      }
4582   }
4583 }
4584 
4585 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4586   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4587   if (w == 0) return ;
4588   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4589     return ;
4590   }
4591 
4592   TEVENT (muxAcquire - Contention) ;
4593   ParkEvent * ReleaseAfter = NULL ;
4594   if (ev == NULL) {
4595     ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4596   }
4597   assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4598   for (;;) {
4599     guarantee (ev->OnList == 0, "invariant") ;
4600     int its = (os::is_MP() ? 100 : 0) + 1 ;
4601 
4602     // Optional spin phase: spin-then-park strategy
4603     while (--its >= 0) {
4604       w = *Lock ;
4605       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4606         if (ReleaseAfter != NULL) {
4607           ParkEvent::Release (ReleaseAfter) ;
4608         }
4609         return ;
4610       }
4611     }
4612 
4613     ev->reset() ;
4614     ev->OnList = intptr_t(Lock) ;
4615     // The following fence() isn't _strictly necessary as the subsequent
4616     // CAS() both serializes execution and ratifies the fetched *Lock value.
4617     OrderAccess::fence();
4618     for (;;) {
4619       w = *Lock ;
4620       if ((w & LOCKBIT) == 0) {
4621         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4622           ev->OnList = 0 ;
4623           // We call ::Release while holding the outer lock, thus
4624           // artificially lengthening the critical section.
4625           // Consider deferring the ::Release() until the subsequent unlock(),
4626           // after we've dropped the outer lock.
4627           if (ReleaseAfter != NULL) {
4628             ParkEvent::Release (ReleaseAfter) ;
4629           }
4630           return ;
4631         }
4632         continue ;      // Interference -- *Lock changed -- Just retry
4633       }
4634       assert (w & LOCKBIT, "invariant") ;
4635       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4636       if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4637     }
4638 
4639     while (ev->OnList != 0) {
4640       ev->park() ;
4641     }
4642   }
4643 }
4644 
4645 // Release() must extract a successor from the list and then wake that thread.
4646 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4647 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4648 // Release() would :
4649 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4650 // (B) Extract a successor from the private list "in-hand"
4651 // (C) attempt to CAS() the residual back into *Lock over null.
4652 //     If there were any newly arrived threads and the CAS() would fail.
4653 //     In that case Release() would detach the RATs, re-merge the list in-hand
4654 //     with the RATs and repeat as needed.  Alternately, Release() might
4655 //     detach and extract a successor, but then pass the residual list to the wakee.
4656 //     The wakee would be responsible for reattaching and remerging before it
4657 //     competed for the lock.
4658 //
4659 // Both "pop" and DMR are immune from ABA corruption -- there can be
4660 // multiple concurrent pushers, but only one popper or detacher.
4661 // This implementation pops from the head of the list.  This is unfair,
4662 // but tends to provide excellent throughput as hot threads remain hot.
4663 // (We wake recently run threads first).
4664 
4665 void Thread::muxRelease (volatile intptr_t * Lock)  {
4666   for (;;) {
4667     const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4668     assert (w & LOCKBIT, "invariant") ;
4669     if (w == LOCKBIT) return ;
4670     ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4671     assert (List != NULL, "invariant") ;
4672     assert (List->OnList == intptr_t(Lock), "invariant") ;
4673     ParkEvent * nxt = List->ListNext ;
4674 
4675     // The following CAS() releases the lock and pops the head element.
4676     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4677       continue ;
4678     }
4679     List->OnList = 0 ;
4680     OrderAccess::fence() ;
4681     List->unpark () ;
4682     return ;
4683   }
4684 }
4685 
4686 
4687 void Threads::verify() {
4688   ALL_JAVA_THREADS(p) {
4689     p->verify();
4690   }
4691   VMThread* thread = VMThread::vm_thread();
4692   if (thread != NULL) thread->verify();
4693 }