1 /*
   2  * Copyright 1997-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 # include "incls/_precompiled.incl"
  26 # include "incls/_thread.cpp.incl"
  27 
  28 #ifdef DTRACE_ENABLED
  29 
  30 // Only bother with this argument setup if dtrace is available
  31 
  32 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
  33 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
  34 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
  35   intptr_t, intptr_t, bool);
  36 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
  37   intptr_t, intptr_t, bool);
  38 
  39 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
  40   {                                                                        \
  41     ResourceMark rm(this);                                                 \
  42     int len = 0;                                                           \
  43     const char* name = (javathread)->get_thread_name();                    \
  44     len = strlen(name);                                                    \
  45     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
  46       name, len,                                                           \
  47       java_lang_Thread::thread_id((javathread)->threadObj()),              \
  48       (javathread)->osthread()->thread_id(),                               \
  49       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
  50   }
  51 
  52 #else //  ndef DTRACE_ENABLED
  53 
  54 #define DTRACE_THREAD_PROBE(probe, javathread)
  55 
  56 #endif // ndef DTRACE_ENABLED
  57 
  58 // Class hierarchy
  59 // - Thread
  60 //   - VMThread
  61 //   - WatcherThread
  62 //   - ConcurrentMarkSweepThread
  63 //   - JavaThread
  64 //     - CompilerThread
  65 
  66 // ======= Thread ========
  67 
  68 // Support for forcing alignment of thread objects for biased locking
  69 void* Thread::operator new(size_t size) {
  70   if (UseBiasedLocking) {
  71     const int alignment = markOopDesc::biased_lock_alignment;
  72     size_t aligned_size = size + (alignment - sizeof(intptr_t));
  73     void* real_malloc_addr = CHeapObj::operator new(aligned_size);
  74     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
  75     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
  76            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
  77            "JavaThread alignment code overflowed allocated storage");
  78     if (TraceBiasedLocking) {
  79       if (aligned_addr != real_malloc_addr)
  80         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
  81                       real_malloc_addr, aligned_addr);
  82     }
  83     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
  84     return aligned_addr;
  85   } else {
  86     return CHeapObj::operator new(size);
  87   }
  88 }
  89 
  90 void Thread::operator delete(void* p) {
  91   if (UseBiasedLocking) {
  92     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
  93     CHeapObj::operator delete(real_malloc_addr);
  94   } else {
  95     CHeapObj::operator delete(p);
  96   }
  97 }
  98 
  99 
 100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 101 // JavaThread
 102 
 103 
 104 Thread::Thread() {
 105   // stack
 106   _stack_base   = NULL;
 107   _stack_size   = 0;
 108   _self_raw_id  = 0;
 109   _lgrp_id      = -1;
 110   _osthread     = NULL;
 111 
 112   // allocated data structures
 113   set_resource_area(new ResourceArea());
 114   set_handle_area(new HandleArea(NULL));
 115   set_active_handles(NULL);
 116   set_free_handle_block(NULL);
 117   set_last_handle_mark(NULL);
 118   set_osthread(NULL);
 119 
 120   // This initial value ==> never claimed.
 121   _oops_do_parity = 0;
 122 
 123   // the handle mark links itself to last_handle_mark
 124   new HandleMark(this);
 125 
 126   // plain initialization
 127   debug_only(_owned_locks = NULL;)
 128   debug_only(_allow_allocation_count = 0;)
 129   NOT_PRODUCT(_allow_safepoint_count = 0;)
 130   NOT_PRODUCT(_skip_gcalot = false;)
 131   CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
 132   _jvmti_env_iteration_count = 0;
 133   _vm_operation_started_count = 0;
 134   _vm_operation_completed_count = 0;
 135   _current_pending_monitor = NULL;
 136   _current_pending_monitor_is_from_java = true;
 137   _current_waiting_monitor = NULL;
 138   _num_nested_signal = 0;
 139   omFreeList = NULL ;
 140   omFreeCount = 0 ;
 141   omFreeProvision = 32 ;
 142 
 143   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
 144   _suspend_flags = 0;
 145 
 146   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 147   _hashStateX = os::random() ;
 148   _hashStateY = 842502087 ;
 149   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
 150   _hashStateW = 273326509 ;
 151 
 152   _OnTrap   = 0 ;
 153   _schedctl = NULL ;
 154   _Stalled  = 0 ;
 155   _TypeTag  = 0x2BAD ;
 156 
 157   // Many of the following fields are effectively final - immutable
 158   // Note that nascent threads can't use the Native Monitor-Mutex
 159   // construct until the _MutexEvent is initialized ...
 160   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 161   // we might instead use a stack of ParkEvents that we could provision on-demand.
 162   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 163   // and ::Release()
 164   _ParkEvent   = ParkEvent::Allocate (this) ;
 165   _SleepEvent  = ParkEvent::Allocate (this) ;
 166   _MutexEvent  = ParkEvent::Allocate (this) ;
 167   _MuxEvent    = ParkEvent::Allocate (this) ;
 168 
 169 #ifdef CHECK_UNHANDLED_OOPS
 170   if (CheckUnhandledOops) {
 171     _unhandled_oops = new UnhandledOops(this);
 172   }
 173 #endif // CHECK_UNHANDLED_OOPS
 174 #ifdef ASSERT
 175   if (UseBiasedLocking) {
 176     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 177     assert(this == _real_malloc_address ||
 178            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 179            "bug in forced alignment of thread objects");
 180   }
 181 #endif /* ASSERT */
 182 }
 183 
 184 void Thread::initialize_thread_local_storage() {
 185   // Note: Make sure this method only calls
 186   // non-blocking operations. Otherwise, it might not work
 187   // with the thread-startup/safepoint interaction.
 188 
 189   // During Java thread startup, safepoint code should allow this
 190   // method to complete because it may need to allocate memory to
 191   // store information for the new thread.
 192 
 193   // initialize structure dependent on thread local storage
 194   ThreadLocalStorage::set_thread(this);
 195 
 196   // set up any platform-specific state.
 197   os::initialize_thread();
 198 
 199 }
 200 
 201 void Thread::record_stack_base_and_size() {
 202   set_stack_base(os::current_stack_base());
 203   set_stack_size(os::current_stack_size());
 204 }
 205 
 206 
 207 Thread::~Thread() {
 208   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 209   ObjectSynchronizer::omFlush (this) ;
 210 
 211   // deallocate data structures
 212   delete resource_area();
 213   // since the handle marks are using the handle area, we have to deallocated the root
 214   // handle mark before deallocating the thread's handle area,
 215   assert(last_handle_mark() != NULL, "check we have an element");
 216   delete last_handle_mark();
 217   assert(last_handle_mark() == NULL, "check we have reached the end");
 218 
 219   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 220   // We NULL out the fields for good hygiene.
 221   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 222   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 223   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 224   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 225 
 226   delete handle_area();
 227 
 228   // osthread() can be NULL, if creation of thread failed.
 229   if (osthread() != NULL) os::free_thread(osthread());
 230 
 231   delete _SR_lock;
 232 
 233   // clear thread local storage if the Thread is deleting itself
 234   if (this == Thread::current()) {
 235     ThreadLocalStorage::set_thread(NULL);
 236   } else {
 237     // In the case where we're not the current thread, invalidate all the
 238     // caches in case some code tries to get the current thread or the
 239     // thread that was destroyed, and gets stale information.
 240     ThreadLocalStorage::invalidate_all();
 241   }
 242   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 243 }
 244 
 245 // NOTE: dummy function for assertion purpose.
 246 void Thread::run() {
 247   ShouldNotReachHere();
 248 }
 249 
 250 #ifdef ASSERT
 251 // Private method to check for dangling thread pointer
 252 void check_for_dangling_thread_pointer(Thread *thread) {
 253  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 254          "possibility of dangling Thread pointer");
 255 }
 256 #endif
 257 
 258 
 259 #ifndef PRODUCT
 260 // Tracing method for basic thread operations
 261 void Thread::trace(const char* msg, const Thread* const thread) {
 262   if (!TraceThreadEvents) return;
 263   ResourceMark rm;
 264   ThreadCritical tc;
 265   const char *name = "non-Java thread";
 266   int prio = -1;
 267   if (thread->is_Java_thread()
 268       && !thread->is_Compiler_thread()) {
 269     // The Threads_lock must be held to get information about
 270     // this thread but may not be in some situations when
 271     // tracing  thread events.
 272     bool release_Threads_lock = false;
 273     if (!Threads_lock->owned_by_self()) {
 274       Threads_lock->lock();
 275       release_Threads_lock = true;
 276     }
 277     JavaThread* jt = (JavaThread *)thread;
 278     name = (char *)jt->get_thread_name();
 279     oop thread_oop = jt->threadObj();
 280     if (thread_oop != NULL) {
 281       prio = java_lang_Thread::priority(thread_oop);
 282     }
 283     if (release_Threads_lock) {
 284       Threads_lock->unlock();
 285     }
 286   }
 287   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 288 }
 289 #endif
 290 
 291 
 292 ThreadPriority Thread::get_priority(const Thread* const thread) {
 293   trace("get priority", thread);
 294   ThreadPriority priority;
 295   // Can return an error!
 296   (void)os::get_priority(thread, priority);
 297   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 298   return priority;
 299 }
 300 
 301 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 302   trace("set priority", thread);
 303   debug_only(check_for_dangling_thread_pointer(thread);)
 304   // Can return an error!
 305   (void)os::set_priority(thread, priority);
 306 }
 307 
 308 
 309 void Thread::start(Thread* thread) {
 310   trace("start", thread);
 311   // Start is different from resume in that its safety is guaranteed by context or
 312   // being called from a Java method synchronized on the Thread object.
 313   if (!DisableStartThread) {
 314     if (thread->is_Java_thread()) {
 315       // Initialize the thread state to RUNNABLE before starting this thread.
 316       // Can not set it after the thread started because we do not know the
 317       // exact thread state at that time. It could be in MONITOR_WAIT or
 318       // in SLEEPING or some other state.
 319       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 320                                           java_lang_Thread::RUNNABLE);
 321     }
 322     os::start_thread(thread);
 323   }
 324 }
 325 
 326 // Enqueue a VM_Operation to do the job for us - sometime later
 327 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 328   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 329   VMThread::execute(vm_stop);
 330 }
 331 
 332 
 333 //
 334 // Check if an external suspend request has completed (or has been
 335 // cancelled). Returns true if the thread is externally suspended and
 336 // false otherwise.
 337 //
 338 // The bits parameter returns information about the code path through
 339 // the routine. Useful for debugging:
 340 //
 341 // set in is_ext_suspend_completed():
 342 // 0x00000001 - routine was entered
 343 // 0x00000010 - routine return false at end
 344 // 0x00000100 - thread exited (return false)
 345 // 0x00000200 - suspend request cancelled (return false)
 346 // 0x00000400 - thread suspended (return true)
 347 // 0x00001000 - thread is in a suspend equivalent state (return true)
 348 // 0x00002000 - thread is native and walkable (return true)
 349 // 0x00004000 - thread is native_trans and walkable (needed retry)
 350 //
 351 // set in wait_for_ext_suspend_completion():
 352 // 0x00010000 - routine was entered
 353 // 0x00020000 - suspend request cancelled before loop (return false)
 354 // 0x00040000 - thread suspended before loop (return true)
 355 // 0x00080000 - suspend request cancelled in loop (return false)
 356 // 0x00100000 - thread suspended in loop (return true)
 357 // 0x00200000 - suspend not completed during retry loop (return false)
 358 //
 359 
 360 // Helper class for tracing suspend wait debug bits.
 361 //
 362 // 0x00000100 indicates that the target thread exited before it could
 363 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 364 // 0x00080000 each indicate a cancelled suspend request so they don't
 365 // count as wait failures either.
 366 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 367 
 368 class TraceSuspendDebugBits : public StackObj {
 369  private:
 370   JavaThread * jt;
 371   bool         is_wait;
 372   bool         called_by_wait;  // meaningful when !is_wait
 373   uint32_t *   bits;
 374 
 375  public:
 376   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 377                         uint32_t *_bits) {
 378     jt             = _jt;
 379     is_wait        = _is_wait;
 380     called_by_wait = _called_by_wait;
 381     bits           = _bits;
 382   }
 383 
 384   ~TraceSuspendDebugBits() {
 385     if (!is_wait) {
 386 #if 1
 387       // By default, don't trace bits for is_ext_suspend_completed() calls.
 388       // That trace is very chatty.
 389       return;
 390 #else
 391       if (!called_by_wait) {
 392         // If tracing for is_ext_suspend_completed() is enabled, then only
 393         // trace calls to it from wait_for_ext_suspend_completion()
 394         return;
 395       }
 396 #endif
 397     }
 398 
 399     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 400       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 401         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 402         ResourceMark rm;
 403 
 404         tty->print_cr(
 405             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 406             jt->get_thread_name(), *bits);
 407 
 408         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 409       }
 410     }
 411   }
 412 };
 413 #undef DEBUG_FALSE_BITS
 414 
 415 
 416 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 417   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 418 
 419   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 420   bool do_trans_retry;           // flag to force the retry
 421 
 422   *bits |= 0x00000001;
 423 
 424   do {
 425     do_trans_retry = false;
 426 
 427     if (is_exiting()) {
 428       // Thread is in the process of exiting. This is always checked
 429       // first to reduce the risk of dereferencing a freed JavaThread.
 430       *bits |= 0x00000100;
 431       return false;
 432     }
 433 
 434     if (!is_external_suspend()) {
 435       // Suspend request is cancelled. This is always checked before
 436       // is_ext_suspended() to reduce the risk of a rogue resume
 437       // confusing the thread that made the suspend request.
 438       *bits |= 0x00000200;
 439       return false;
 440     }
 441 
 442     if (is_ext_suspended()) {
 443       // thread is suspended
 444       *bits |= 0x00000400;
 445       return true;
 446     }
 447 
 448     // Now that we no longer do hard suspends of threads running
 449     // native code, the target thread can be changing thread state
 450     // while we are in this routine:
 451     //
 452     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 453     //
 454     // We save a copy of the thread state as observed at this moment
 455     // and make our decision about suspend completeness based on the
 456     // copy. This closes the race where the thread state is seen as
 457     // _thread_in_native_trans in the if-thread_blocked check, but is
 458     // seen as _thread_blocked in if-thread_in_native_trans check.
 459     JavaThreadState save_state = thread_state();
 460 
 461     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 462       // If the thread's state is _thread_blocked and this blocking
 463       // condition is known to be equivalent to a suspend, then we can
 464       // consider the thread to be externally suspended. This means that
 465       // the code that sets _thread_blocked has been modified to do
 466       // self-suspension if the blocking condition releases. We also
 467       // used to check for CONDVAR_WAIT here, but that is now covered by
 468       // the _thread_blocked with self-suspension check.
 469       //
 470       // Return true since we wouldn't be here unless there was still an
 471       // external suspend request.
 472       *bits |= 0x00001000;
 473       return true;
 474     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 475       // Threads running native code will self-suspend on native==>VM/Java
 476       // transitions. If its stack is walkable (should always be the case
 477       // unless this function is called before the actual java_suspend()
 478       // call), then the wait is done.
 479       *bits |= 0x00002000;
 480       return true;
 481     } else if (!called_by_wait && !did_trans_retry &&
 482                save_state == _thread_in_native_trans &&
 483                frame_anchor()->walkable()) {
 484       // The thread is transitioning from thread_in_native to another
 485       // thread state. check_safepoint_and_suspend_for_native_trans()
 486       // will force the thread to self-suspend. If it hasn't gotten
 487       // there yet we may have caught the thread in-between the native
 488       // code check above and the self-suspend. Lucky us. If we were
 489       // called by wait_for_ext_suspend_completion(), then it
 490       // will be doing the retries so we don't have to.
 491       //
 492       // Since we use the saved thread state in the if-statement above,
 493       // there is a chance that the thread has already transitioned to
 494       // _thread_blocked by the time we get here. In that case, we will
 495       // make a single unnecessary pass through the logic below. This
 496       // doesn't hurt anything since we still do the trans retry.
 497 
 498       *bits |= 0x00004000;
 499 
 500       // Once the thread leaves thread_in_native_trans for another
 501       // thread state, we break out of this retry loop. We shouldn't
 502       // need this flag to prevent us from getting back here, but
 503       // sometimes paranoia is good.
 504       did_trans_retry = true;
 505 
 506       // We wait for the thread to transition to a more usable state.
 507       for (int i = 1; i <= SuspendRetryCount; i++) {
 508         // We used to do an "os::yield_all(i)" call here with the intention
 509         // that yielding would increase on each retry. However, the parameter
 510         // is ignored on Linux which means the yield didn't scale up. Waiting
 511         // on the SR_lock below provides a much more predictable scale up for
 512         // the delay. It also provides a simple/direct point to check for any
 513         // safepoint requests from the VMThread
 514 
 515         // temporarily drops SR_lock while doing wait with safepoint check
 516         // (if we're a JavaThread - the WatcherThread can also call this)
 517         // and increase delay with each retry
 518         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 519 
 520         // check the actual thread state instead of what we saved above
 521         if (thread_state() != _thread_in_native_trans) {
 522           // the thread has transitioned to another thread state so
 523           // try all the checks (except this one) one more time.
 524           do_trans_retry = true;
 525           break;
 526         }
 527       } // end retry loop
 528 
 529 
 530     }
 531   } while (do_trans_retry);
 532 
 533   *bits |= 0x00000010;
 534   return false;
 535 }
 536 
 537 //
 538 // Wait for an external suspend request to complete (or be cancelled).
 539 // Returns true if the thread is externally suspended and false otherwise.
 540 //
 541 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 542        uint32_t *bits) {
 543   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 544                              false /* !called_by_wait */, bits);
 545 
 546   // local flag copies to minimize SR_lock hold time
 547   bool is_suspended;
 548   bool pending;
 549   uint32_t reset_bits;
 550 
 551   // set a marker so is_ext_suspend_completed() knows we are the caller
 552   *bits |= 0x00010000;
 553 
 554   // We use reset_bits to reinitialize the bits value at the top of
 555   // each retry loop. This allows the caller to make use of any
 556   // unused bits for their own marking purposes.
 557   reset_bits = *bits;
 558 
 559   {
 560     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 561     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 562                                             delay, bits);
 563     pending = is_external_suspend();
 564   }
 565   // must release SR_lock to allow suspension to complete
 566 
 567   if (!pending) {
 568     // A cancelled suspend request is the only false return from
 569     // is_ext_suspend_completed() that keeps us from entering the
 570     // retry loop.
 571     *bits |= 0x00020000;
 572     return false;
 573   }
 574 
 575   if (is_suspended) {
 576     *bits |= 0x00040000;
 577     return true;
 578   }
 579 
 580   for (int i = 1; i <= retries; i++) {
 581     *bits = reset_bits;  // reinit to only track last retry
 582 
 583     // We used to do an "os::yield_all(i)" call here with the intention
 584     // that yielding would increase on each retry. However, the parameter
 585     // is ignored on Linux which means the yield didn't scale up. Waiting
 586     // on the SR_lock below provides a much more predictable scale up for
 587     // the delay. It also provides a simple/direct point to check for any
 588     // safepoint requests from the VMThread
 589 
 590     {
 591       MutexLocker ml(SR_lock());
 592       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 593       // can also call this)  and increase delay with each retry
 594       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 595 
 596       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 597                                               delay, bits);
 598 
 599       // It is possible for the external suspend request to be cancelled
 600       // (by a resume) before the actual suspend operation is completed.
 601       // Refresh our local copy to see if we still need to wait.
 602       pending = is_external_suspend();
 603     }
 604 
 605     if (!pending) {
 606       // A cancelled suspend request is the only false return from
 607       // is_ext_suspend_completed() that keeps us from staying in the
 608       // retry loop.
 609       *bits |= 0x00080000;
 610       return false;
 611     }
 612 
 613     if (is_suspended) {
 614       *bits |= 0x00100000;
 615       return true;
 616     }
 617   } // end retry loop
 618 
 619   // thread did not suspend after all our retries
 620   *bits |= 0x00200000;
 621   return false;
 622 }
 623 
 624 #ifndef PRODUCT
 625 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 626 
 627   // This should not need to be atomic as the only way for simultaneous
 628   // updates is via interrupts. Even then this should be rare or non-existant
 629   // and we don't care that much anyway.
 630 
 631   int index = _jmp_ring_index;
 632   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 633   _jmp_ring[index]._target = (intptr_t) target;
 634   _jmp_ring[index]._instruction = (intptr_t) instr;
 635   _jmp_ring[index]._file = file;
 636   _jmp_ring[index]._line = line;
 637 }
 638 #endif /* PRODUCT */
 639 
 640 // Called by flat profiler
 641 // Callers have already called wait_for_ext_suspend_completion
 642 // The assertion for that is currently too complex to put here:
 643 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 644   bool gotframe = false;
 645   // self suspension saves needed state.
 646   if (has_last_Java_frame() && _anchor.walkable()) {
 647      *_fr = pd_last_frame();
 648      gotframe = true;
 649   }
 650   return gotframe;
 651 }
 652 
 653 void Thread::interrupt(Thread* thread) {
 654   trace("interrupt", thread);
 655   debug_only(check_for_dangling_thread_pointer(thread);)
 656   os::interrupt(thread);
 657 }
 658 
 659 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 660   trace("is_interrupted", thread);
 661   debug_only(check_for_dangling_thread_pointer(thread);)
 662   // Note:  If clear_interrupted==false, this simply fetches and
 663   // returns the value of the field osthread()->interrupted().
 664   return os::is_interrupted(thread, clear_interrupted);
 665 }
 666 
 667 
 668 // GC Support
 669 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 670   jint thread_parity = _oops_do_parity;
 671   if (thread_parity != strong_roots_parity) {
 672     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 673     if (res == thread_parity) return true;
 674     else {
 675       guarantee(res == strong_roots_parity, "Or else what?");
 676       assert(SharedHeap::heap()->n_par_threads() > 0,
 677              "Should only fail when parallel.");
 678       return false;
 679     }
 680   }
 681   assert(SharedHeap::heap()->n_par_threads() > 0,
 682          "Should only fail when parallel.");
 683   return false;
 684 }
 685 
 686 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 687   active_handles()->oops_do(f);
 688   // Do oop for ThreadShadow
 689   f->do_oop((oop*)&_pending_exception);
 690   handle_area()->oops_do(f);
 691 }
 692 
 693 void Thread::nmethods_do(CodeBlobClosure* cf) {
 694   // no nmethods in a generic thread...
 695 }
 696 
 697 void Thread::print_on(outputStream* st) const {
 698   // get_priority assumes osthread initialized
 699   if (osthread() != NULL) {
 700     st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
 701     osthread()->print_on(st);
 702   }
 703   debug_only(if (WizardMode) print_owned_locks_on(st);)
 704 }
 705 
 706 // Thread::print_on_error() is called by fatal error handler. Don't use
 707 // any lock or allocate memory.
 708 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 709   if      (is_VM_thread())                  st->print("VMThread");
 710   else if (is_Compiler_thread())            st->print("CompilerThread");
 711   else if (is_Java_thread())                st->print("JavaThread");
 712   else if (is_GC_task_thread())             st->print("GCTaskThread");
 713   else if (is_Watcher_thread())             st->print("WatcherThread");
 714   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 715   else st->print("Thread");
 716 
 717   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 718             _stack_base - _stack_size, _stack_base);
 719 
 720   if (osthread()) {
 721     st->print(" [id=%d]", osthread()->thread_id());
 722   }
 723 }
 724 
 725 #ifdef ASSERT
 726 void Thread::print_owned_locks_on(outputStream* st) const {
 727   Monitor *cur = _owned_locks;
 728   if (cur == NULL) {
 729     st->print(" (no locks) ");
 730   } else {
 731     st->print_cr(" Locks owned:");
 732     while(cur) {
 733       cur->print_on(st);
 734       cur = cur->next();
 735     }
 736   }
 737 }
 738 
 739 static int ref_use_count  = 0;
 740 
 741 bool Thread::owns_locks_but_compiled_lock() const {
 742   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 743     if (cur != Compile_lock) return true;
 744   }
 745   return false;
 746 }
 747 
 748 
 749 #endif
 750 
 751 #ifndef PRODUCT
 752 
 753 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 754 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 755 // no threads which allow_vm_block's are held
 756 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 757     // Check if current thread is allowed to block at a safepoint
 758     if (!(_allow_safepoint_count == 0))
 759       fatal("Possible safepoint reached by thread that does not allow it");
 760     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 761       fatal("LEAF method calling lock?");
 762     }
 763 
 764 #ifdef ASSERT
 765     if (potential_vm_operation && is_Java_thread()
 766         && !Universe::is_bootstrapping()) {
 767       // Make sure we do not hold any locks that the VM thread also uses.
 768       // This could potentially lead to deadlocks
 769       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 770         // Threads_lock is special, since the safepoint synchronization will not start before this is
 771         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 772         // since it is used to transfer control between JavaThreads and the VMThread
 773         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
 774         if ( (cur->allow_vm_block() &&
 775               cur != Threads_lock &&
 776               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
 777               cur != VMOperationRequest_lock &&
 778               cur != VMOperationQueue_lock) ||
 779               cur->rank() == Mutex::special) {
 780           warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 781         }
 782       }
 783     }
 784 
 785     if (GCALotAtAllSafepoints) {
 786       // We could enter a safepoint here and thus have a gc
 787       InterfaceSupport::check_gc_alot();
 788     }
 789 #endif
 790 }
 791 #endif
 792 
 793 bool Thread::is_in_stack(address adr) const {
 794   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 795   address end = os::current_stack_pointer();
 796   if (stack_base() >= adr && adr >= end) return true;
 797 
 798   return false;
 799 }
 800 
 801 
 802 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 803 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 804 // used for compilation in the future. If that change is made, the need for these methods
 805 // should be revisited, and they should be removed if possible.
 806 
 807 bool Thread::is_lock_owned(address adr) const {
 808   return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
 809 }
 810 
 811 bool Thread::set_as_starting_thread() {
 812  // NOTE: this must be called inside the main thread.
 813   return os::create_main_thread((JavaThread*)this);
 814 }
 815 
 816 static void initialize_class(symbolHandle class_name, TRAPS) {
 817   klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 818   instanceKlass::cast(klass)->initialize(CHECK);
 819 }
 820 
 821 
 822 // Creates the initial ThreadGroup
 823 static Handle create_initial_thread_group(TRAPS) {
 824   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH);
 825   instanceKlassHandle klass (THREAD, k);
 826 
 827   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
 828   {
 829     JavaValue result(T_VOID);
 830     JavaCalls::call_special(&result,
 831                             system_instance,
 832                             klass,
 833                             vmSymbolHandles::object_initializer_name(),
 834                             vmSymbolHandles::void_method_signature(),
 835                             CHECK_NH);
 836   }
 837   Universe::set_system_thread_group(system_instance());
 838 
 839   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
 840   {
 841     JavaValue result(T_VOID);
 842     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 843     JavaCalls::call_special(&result,
 844                             main_instance,
 845                             klass,
 846                             vmSymbolHandles::object_initializer_name(),
 847                             vmSymbolHandles::threadgroup_string_void_signature(),
 848                             system_instance,
 849                             string,
 850                             CHECK_NH);
 851   }
 852   return main_instance;
 853 }
 854 
 855 // Creates the initial Thread
 856 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
 857   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL);
 858   instanceKlassHandle klass (THREAD, k);
 859   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
 860 
 861   java_lang_Thread::set_thread(thread_oop(), thread);
 862   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 863   thread->set_threadObj(thread_oop());
 864 
 865   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
 866 
 867   JavaValue result(T_VOID);
 868   JavaCalls::call_special(&result, thread_oop,
 869                                    klass,
 870                                    vmSymbolHandles::object_initializer_name(),
 871                                    vmSymbolHandles::threadgroup_string_void_signature(),
 872                                    thread_group,
 873                                    string,
 874                                    CHECK_NULL);
 875   return thread_oop();
 876 }
 877 
 878 static void call_initializeSystemClass(TRAPS) {
 879   klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
 880   instanceKlassHandle klass (THREAD, k);
 881 
 882   JavaValue result(T_VOID);
 883   JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(),
 884                                          vmSymbolHandles::void_method_signature(), CHECK);
 885 }
 886 
 887 static void reset_vm_info_property(TRAPS) {
 888   // the vm info string
 889   ResourceMark rm(THREAD);
 890   const char *vm_info = VM_Version::vm_info_string();
 891 
 892   // java.lang.System class
 893   klassOop k =  SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
 894   instanceKlassHandle klass (THREAD, k);
 895 
 896   // setProperty arguments
 897   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
 898   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
 899 
 900   // return value
 901   JavaValue r(T_OBJECT);
 902 
 903   // public static String setProperty(String key, String value);
 904   JavaCalls::call_static(&r,
 905                          klass,
 906                          vmSymbolHandles::setProperty_name(),
 907                          vmSymbolHandles::string_string_string_signature(),
 908                          key_str,
 909                          value_str,
 910                          CHECK);
 911 }
 912 
 913 
 914 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
 915   assert(thread_group.not_null(), "thread group should be specified");
 916   assert(threadObj() == NULL, "should only create Java thread object once");
 917 
 918   klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
 919   instanceKlassHandle klass (THREAD, k);
 920   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
 921 
 922   java_lang_Thread::set_thread(thread_oop(), this);
 923   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 924   set_threadObj(thread_oop());
 925 
 926   JavaValue result(T_VOID);
 927   if (thread_name != NULL) {
 928     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 929     // Thread gets assigned specified name and null target
 930     JavaCalls::call_special(&result,
 931                             thread_oop,
 932                             klass,
 933                             vmSymbolHandles::object_initializer_name(),
 934                             vmSymbolHandles::threadgroup_string_void_signature(),
 935                             thread_group, // Argument 1
 936                             name,         // Argument 2
 937                             THREAD);
 938   } else {
 939     // Thread gets assigned name "Thread-nnn" and null target
 940     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 941     JavaCalls::call_special(&result,
 942                             thread_oop,
 943                             klass,
 944                             vmSymbolHandles::object_initializer_name(),
 945                             vmSymbolHandles::threadgroup_runnable_void_signature(),
 946                             thread_group, // Argument 1
 947                             Handle(),     // Argument 2
 948                             THREAD);
 949   }
 950 
 951 
 952   if (daemon) {
 953       java_lang_Thread::set_daemon(thread_oop());
 954   }
 955 
 956   if (HAS_PENDING_EXCEPTION) {
 957     return;
 958   }
 959 
 960   KlassHandle group(this, SystemDictionary::threadGroup_klass());
 961   Handle threadObj(this, this->threadObj());
 962 
 963   JavaCalls::call_special(&result,
 964                          thread_group,
 965                          group,
 966                          vmSymbolHandles::add_method_name(),
 967                          vmSymbolHandles::thread_void_signature(),
 968                          threadObj,          // Arg 1
 969                          THREAD);
 970 
 971 
 972 }
 973 
 974 // NamedThread --  non-JavaThread subclasses with multiple
 975 // uniquely named instances should derive from this.
 976 NamedThread::NamedThread() : Thread() {
 977   _name = NULL;
 978 }
 979 
 980 NamedThread::~NamedThread() {
 981   if (_name != NULL) {
 982     FREE_C_HEAP_ARRAY(char, _name);
 983     _name = NULL;
 984   }
 985 }
 986 
 987 void NamedThread::set_name(const char* format, ...) {
 988   guarantee(_name == NULL, "Only get to set name once.");
 989   _name = NEW_C_HEAP_ARRAY(char, max_name_len);
 990   guarantee(_name != NULL, "alloc failure");
 991   va_list ap;
 992   va_start(ap, format);
 993   jio_vsnprintf(_name, max_name_len, format, ap);
 994   va_end(ap);
 995 }
 996 
 997 // ======= WatcherThread ========
 998 
 999 // The watcher thread exists to simulate timer interrupts.  It should
1000 // be replaced by an abstraction over whatever native support for
1001 // timer interrupts exists on the platform.
1002 
1003 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1004 bool           WatcherThread::_should_terminate = false;
1005 
1006 WatcherThread::WatcherThread() : Thread() {
1007   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1008   if (os::create_thread(this, os::watcher_thread)) {
1009     _watcher_thread = this;
1010 
1011     // Set the watcher thread to the highest OS priority which should not be
1012     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1013     // is created. The only normal thread using this priority is the reference
1014     // handler thread, which runs for very short intervals only.
1015     // If the VMThread's priority is not lower than the WatcherThread profiling
1016     // will be inaccurate.
1017     os::set_priority(this, MaxPriority);
1018     if (!DisableStartThread) {
1019       os::start_thread(this);
1020     }
1021   }
1022 }
1023 
1024 void WatcherThread::run() {
1025   assert(this == watcher_thread(), "just checking");
1026 
1027   this->record_stack_base_and_size();
1028   this->initialize_thread_local_storage();
1029   this->set_active_handles(JNIHandleBlock::allocate_block());
1030   while(!_should_terminate) {
1031     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1032     assert(watcher_thread() == this,  "thread consistency check");
1033 
1034     // Calculate how long it'll be until the next PeriodicTask work
1035     // should be done, and sleep that amount of time.
1036     const size_t time_to_wait = PeriodicTask::time_to_wait();
1037     os::sleep(this, time_to_wait, false);
1038 
1039     if (is_error_reported()) {
1040       // A fatal error has happened, the error handler(VMError::report_and_die)
1041       // should abort JVM after creating an error log file. However in some
1042       // rare cases, the error handler itself might deadlock. Here we try to
1043       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1044       //
1045       // This code is in WatcherThread because WatcherThread wakes up
1046       // periodically so the fatal error handler doesn't need to do anything;
1047       // also because the WatcherThread is less likely to crash than other
1048       // threads.
1049 
1050       for (;;) {
1051         if (!ShowMessageBoxOnError
1052          && (OnError == NULL || OnError[0] == '\0')
1053          && Arguments::abort_hook() == NULL) {
1054              os::sleep(this, 2 * 60 * 1000, false);
1055              fdStream err(defaultStream::output_fd());
1056              err.print_raw_cr("# [ timer expired, abort... ]");
1057              // skip atexit/vm_exit/vm_abort hooks
1058              os::die();
1059         }
1060 
1061         // Wake up 5 seconds later, the fatal handler may reset OnError or
1062         // ShowMessageBoxOnError when it is ready to abort.
1063         os::sleep(this, 5 * 1000, false);
1064       }
1065     }
1066 
1067     PeriodicTask::real_time_tick(time_to_wait);
1068 
1069     // If we have no more tasks left due to dynamic disenrollment,
1070     // shut down the thread since we don't currently support dynamic enrollment
1071     if (PeriodicTask::num_tasks() == 0) {
1072       _should_terminate = true;
1073     }
1074   }
1075 
1076   // Signal that it is terminated
1077   {
1078     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1079     _watcher_thread = NULL;
1080     Terminator_lock->notify();
1081   }
1082 
1083   // Thread destructor usually does this..
1084   ThreadLocalStorage::set_thread(NULL);
1085 }
1086 
1087 void WatcherThread::start() {
1088   if (watcher_thread() == NULL) {
1089     _should_terminate = false;
1090     // Create the single instance of WatcherThread
1091     new WatcherThread();
1092   }
1093 }
1094 
1095 void WatcherThread::stop() {
1096   // it is ok to take late safepoints here, if needed
1097   MutexLocker mu(Terminator_lock);
1098   _should_terminate = true;
1099   while(watcher_thread() != NULL) {
1100     // This wait should make safepoint checks, wait without a timeout,
1101     // and wait as a suspend-equivalent condition.
1102     //
1103     // Note: If the FlatProfiler is running, then this thread is waiting
1104     // for the WatcherThread to terminate and the WatcherThread, via the
1105     // FlatProfiler task, is waiting for the external suspend request on
1106     // this thread to complete. wait_for_ext_suspend_completion() will
1107     // eventually timeout, but that takes time. Making this wait a
1108     // suspend-equivalent condition solves that timeout problem.
1109     //
1110     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1111                           Mutex::_as_suspend_equivalent_flag);
1112   }
1113 }
1114 
1115 void WatcherThread::print_on(outputStream* st) const {
1116   st->print("\"%s\" ", name());
1117   Thread::print_on(st);
1118   st->cr();
1119 }
1120 
1121 // ======= JavaThread ========
1122 
1123 // A JavaThread is a normal Java thread
1124 
1125 void JavaThread::initialize() {
1126   // Initialize fields
1127 
1128   // Set the claimed par_id to -1 (ie not claiming any par_ids)
1129   set_claimed_par_id(-1);
1130 
1131   set_saved_exception_pc(NULL);
1132   set_threadObj(NULL);
1133   _anchor.clear();
1134   set_entry_point(NULL);
1135   set_jni_functions(jni_functions());
1136   set_callee_target(NULL);
1137   set_vm_result(NULL);
1138   set_vm_result_2(NULL);
1139   set_vframe_array_head(NULL);
1140   set_vframe_array_last(NULL);
1141   set_deferred_locals(NULL);
1142   set_deopt_mark(NULL);
1143   clear_must_deopt_id();
1144   set_monitor_chunks(NULL);
1145   set_next(NULL);
1146   set_thread_state(_thread_new);
1147   _terminated = _not_terminated;
1148   _privileged_stack_top = NULL;
1149   _array_for_gc = NULL;
1150   _suspend_equivalent = false;
1151   _in_deopt_handler = 0;
1152   _doing_unsafe_access = false;
1153   _stack_guard_state = stack_guard_unused;
1154   _exception_oop = NULL;
1155   _exception_pc  = 0;
1156   _exception_handler_pc = 0;
1157   _exception_stack_size = 0;
1158   _jvmti_thread_state= NULL;
1159   _jvmti_get_loaded_classes_closure = NULL;
1160   _interp_only_mode    = 0;
1161   _special_runtime_exit_condition = _no_async_condition;
1162   _pending_async_exception = NULL;
1163   _is_compiling = false;
1164   _thread_stat = NULL;
1165   _thread_stat = new ThreadStatistics();
1166   _blocked_on_compilation = false;
1167   _jni_active_critical = 0;
1168   _do_not_unlock_if_synchronized = false;
1169   _cached_monitor_info = NULL;
1170   _parker = Parker::Allocate(this) ;
1171 
1172 #ifndef PRODUCT
1173   _jmp_ring_index = 0;
1174   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1175     record_jump(NULL, NULL, NULL, 0);
1176   }
1177 #endif /* PRODUCT */
1178 
1179   set_thread_profiler(NULL);
1180   if (FlatProfiler::is_active()) {
1181     // This is where we would decide to either give each thread it's own profiler
1182     // or use one global one from FlatProfiler,
1183     // or up to some count of the number of profiled threads, etc.
1184     ThreadProfiler* pp = new ThreadProfiler();
1185     pp->engage();
1186     set_thread_profiler(pp);
1187   }
1188 
1189   // Setup safepoint state info for this thread
1190   ThreadSafepointState::create(this);
1191 
1192   debug_only(_java_call_counter = 0);
1193 
1194   // JVMTI PopFrame support
1195   _popframe_condition = popframe_inactive;
1196   _popframe_preserved_args = NULL;
1197   _popframe_preserved_args_size = 0;
1198 
1199   pd_initialize();
1200 }
1201 
1202 #ifndef SERIALGC
1203 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1204 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1205 #endif // !SERIALGC
1206 
1207 JavaThread::JavaThread(bool is_attaching) :
1208   Thread()
1209 #ifndef SERIALGC
1210   , _satb_mark_queue(&_satb_mark_queue_set),
1211   _dirty_card_queue(&_dirty_card_queue_set)
1212 #endif // !SERIALGC
1213 {
1214   initialize();
1215   _is_attaching = is_attaching;
1216   assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1217 }
1218 
1219 bool JavaThread::reguard_stack(address cur_sp) {
1220   if (_stack_guard_state != stack_guard_yellow_disabled) {
1221     return true; // Stack already guarded or guard pages not needed.
1222   }
1223 
1224   if (register_stack_overflow()) {
1225     // For those architectures which have separate register and
1226     // memory stacks, we must check the register stack to see if
1227     // it has overflowed.
1228     return false;
1229   }
1230 
1231   // Java code never executes within the yellow zone: the latter is only
1232   // there to provoke an exception during stack banging.  If java code
1233   // is executing there, either StackShadowPages should be larger, or
1234   // some exception code in c1, c2 or the interpreter isn't unwinding
1235   // when it should.
1236   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1237 
1238   enable_stack_yellow_zone();
1239   return true;
1240 }
1241 
1242 bool JavaThread::reguard_stack(void) {
1243   return reguard_stack(os::current_stack_pointer());
1244 }
1245 
1246 
1247 void JavaThread::block_if_vm_exited() {
1248   if (_terminated == _vm_exited) {
1249     // _vm_exited is set at safepoint, and Threads_lock is never released
1250     // we will block here forever
1251     Threads_lock->lock_without_safepoint_check();
1252     ShouldNotReachHere();
1253   }
1254 }
1255 
1256 
1257 // Remove this ifdef when C1 is ported to the compiler interface.
1258 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1259 
1260 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1261   Thread()
1262 #ifndef SERIALGC
1263   , _satb_mark_queue(&_satb_mark_queue_set),
1264   _dirty_card_queue(&_dirty_card_queue_set)
1265 #endif // !SERIALGC
1266 {
1267   if (TraceThreadEvents) {
1268     tty->print_cr("creating thread %p", this);
1269   }
1270   initialize();
1271   _is_attaching = false;
1272   set_entry_point(entry_point);
1273   // Create the native thread itself.
1274   // %note runtime_23
1275   os::ThreadType thr_type = os::java_thread;
1276   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1277                                                      os::java_thread;
1278   os::create_thread(this, thr_type, stack_sz);
1279 
1280   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1281   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1282   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1283   // the exception consists of creating the exception object & initializing it, initialization
1284   // will leave the VM via a JavaCall and then all locks must be unlocked).
1285   //
1286   // The thread is still suspended when we reach here. Thread must be explicit started
1287   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1288   // by calling Threads:add. The reason why this is not done here, is because the thread
1289   // object must be fully initialized (take a look at JVM_Start)
1290 }
1291 
1292 JavaThread::~JavaThread() {
1293   if (TraceThreadEvents) {
1294       tty->print_cr("terminate thread %p", this);
1295   }
1296 
1297   // JSR166 -- return the parker to the free list
1298   Parker::Release(_parker);
1299   _parker = NULL ;
1300 
1301   // Free any remaining  previous UnrollBlock
1302   vframeArray* old_array = vframe_array_last();
1303 
1304   if (old_array != NULL) {
1305     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1306     old_array->set_unroll_block(NULL);
1307     delete old_info;
1308     delete old_array;
1309   }
1310 
1311   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1312   if (deferred != NULL) {
1313     // This can only happen if thread is destroyed before deoptimization occurs.
1314     assert(deferred->length() != 0, "empty array!");
1315     do {
1316       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1317       deferred->remove_at(0);
1318       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1319       delete dlv;
1320     } while (deferred->length() != 0);
1321     delete deferred;
1322   }
1323 
1324   // All Java related clean up happens in exit
1325   ThreadSafepointState::destroy(this);
1326   if (_thread_profiler != NULL) delete _thread_profiler;
1327   if (_thread_stat != NULL) delete _thread_stat;
1328 }
1329 
1330 
1331 // The first routine called by a new Java thread
1332 void JavaThread::run() {
1333   // initialize thread-local alloc buffer related fields
1334   this->initialize_tlab();
1335 
1336   // used to test validitity of stack trace backs
1337   this->record_base_of_stack_pointer();
1338 
1339   // Record real stack base and size.
1340   this->record_stack_base_and_size();
1341 
1342   // Initialize thread local storage; set before calling MutexLocker
1343   this->initialize_thread_local_storage();
1344 
1345   this->create_stack_guard_pages();
1346 
1347   // Thread is now sufficient initialized to be handled by the safepoint code as being
1348   // in the VM. Change thread state from _thread_new to _thread_in_vm
1349   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1350 
1351   assert(JavaThread::current() == this, "sanity check");
1352   assert(!Thread::current()->owns_locks(), "sanity check");
1353 
1354   DTRACE_THREAD_PROBE(start, this);
1355 
1356   // This operation might block. We call that after all safepoint checks for a new thread has
1357   // been completed.
1358   this->set_active_handles(JNIHandleBlock::allocate_block());
1359 
1360   if (JvmtiExport::should_post_thread_life()) {
1361     JvmtiExport::post_thread_start(this);
1362   }
1363 
1364   // We call another function to do the rest so we are sure that the stack addresses used
1365   // from there will be lower than the stack base just computed
1366   thread_main_inner();
1367 
1368   // Note, thread is no longer valid at this point!
1369 }
1370 
1371 
1372 void JavaThread::thread_main_inner() {
1373   assert(JavaThread::current() == this, "sanity check");
1374   assert(this->threadObj() != NULL, "just checking");
1375 
1376   // Execute thread entry point. If this thread is being asked to restart,
1377   // or has been stopped before starting, do not reexecute entry point.
1378   // Note: Due to JVM_StopThread we can have pending exceptions already!
1379   if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) {
1380     // enter the thread's entry point only if we have no pending exceptions
1381     HandleMark hm(this);
1382     this->entry_point()(this, this);
1383   }
1384 
1385   DTRACE_THREAD_PROBE(stop, this);
1386 
1387   this->exit(false);
1388   delete this;
1389 }
1390 
1391 
1392 static void ensure_join(JavaThread* thread) {
1393   // We do not need to grap the Threads_lock, since we are operating on ourself.
1394   Handle threadObj(thread, thread->threadObj());
1395   assert(threadObj.not_null(), "java thread object must exist");
1396   ObjectLocker lock(threadObj, thread);
1397   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1398   thread->clear_pending_exception();
1399   // It is of profound importance that we set the stillborn bit and reset the thread object,
1400   // before we do the notify. Since, changing these two variable will make JVM_IsAlive return
1401   // false. So in case another thread is doing a join on this thread , it will detect that the thread
1402   // is dead when it gets notified.
1403   java_lang_Thread::set_stillborn(threadObj());
1404   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1405   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1406   java_lang_Thread::set_thread(threadObj(), NULL);
1407   lock.notify_all(thread);
1408   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1409   thread->clear_pending_exception();
1410 }
1411 
1412 
1413 // For any new cleanup additions, please check to see if they need to be applied to
1414 // cleanup_failed_attach_current_thread as well.
1415 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1416   assert(this == JavaThread::current(),  "thread consistency check");
1417   if (!InitializeJavaLangSystem) return;
1418 
1419   HandleMark hm(this);
1420   Handle uncaught_exception(this, this->pending_exception());
1421   this->clear_pending_exception();
1422   Handle threadObj(this, this->threadObj());
1423   assert(threadObj.not_null(), "Java thread object should be created");
1424 
1425   if (get_thread_profiler() != NULL) {
1426     get_thread_profiler()->disengage();
1427     ResourceMark rm;
1428     get_thread_profiler()->print(get_thread_name());
1429   }
1430 
1431 
1432   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1433   {
1434     EXCEPTION_MARK;
1435 
1436     CLEAR_PENDING_EXCEPTION;
1437   }
1438   // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1439   // has to be fixed by a runtime query method
1440   if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1441     // JSR-166: change call from from ThreadGroup.uncaughtException to
1442     // java.lang.Thread.dispatchUncaughtException
1443     if (uncaught_exception.not_null()) {
1444       Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1445       Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1446         (address)uncaught_exception(), (address)threadObj(), (address)group());
1447       {
1448         EXCEPTION_MARK;
1449         // Check if the method Thread.dispatchUncaughtException() exists. If so
1450         // call it.  Otherwise we have an older library without the JSR-166 changes,
1451         // so call ThreadGroup.uncaughtException()
1452         KlassHandle recvrKlass(THREAD, threadObj->klass());
1453         CallInfo callinfo;
1454         KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1455         LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1456                                            vmSymbolHandles::dispatchUncaughtException_name(),
1457                                            vmSymbolHandles::throwable_void_signature(),
1458                                            KlassHandle(), false, false, THREAD);
1459         CLEAR_PENDING_EXCEPTION;
1460         methodHandle method = callinfo.selected_method();
1461         if (method.not_null()) {
1462           JavaValue result(T_VOID);
1463           JavaCalls::call_virtual(&result,
1464                                   threadObj, thread_klass,
1465                                   vmSymbolHandles::dispatchUncaughtException_name(),
1466                                   vmSymbolHandles::throwable_void_signature(),
1467                                   uncaught_exception,
1468                                   THREAD);
1469         } else {
1470           KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass());
1471           JavaValue result(T_VOID);
1472           JavaCalls::call_virtual(&result,
1473                                   group, thread_group,
1474                                   vmSymbolHandles::uncaughtException_name(),
1475                                   vmSymbolHandles::thread_throwable_void_signature(),
1476                                   threadObj,           // Arg 1
1477                                   uncaught_exception,  // Arg 2
1478                                   THREAD);
1479         }
1480         CLEAR_PENDING_EXCEPTION;
1481       }
1482     }
1483 
1484     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1485     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1486     // is deprecated anyhow.
1487     { int count = 3;
1488       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1489         EXCEPTION_MARK;
1490         JavaValue result(T_VOID);
1491         KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass());
1492         JavaCalls::call_virtual(&result,
1493                               threadObj, thread_klass,
1494                               vmSymbolHandles::exit_method_name(),
1495                               vmSymbolHandles::void_method_signature(),
1496                               THREAD);
1497         CLEAR_PENDING_EXCEPTION;
1498       }
1499     }
1500 
1501     // notify JVMTI
1502     if (JvmtiExport::should_post_thread_life()) {
1503       JvmtiExport::post_thread_end(this);
1504     }
1505 
1506     // We have notified the agents that we are exiting, before we go on,
1507     // we must check for a pending external suspend request and honor it
1508     // in order to not surprise the thread that made the suspend request.
1509     while (true) {
1510       {
1511         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1512         if (!is_external_suspend()) {
1513           set_terminated(_thread_exiting);
1514           ThreadService::current_thread_exiting(this);
1515           break;
1516         }
1517         // Implied else:
1518         // Things get a little tricky here. We have a pending external
1519         // suspend request, but we are holding the SR_lock so we
1520         // can't just self-suspend. So we temporarily drop the lock
1521         // and then self-suspend.
1522       }
1523 
1524       ThreadBlockInVM tbivm(this);
1525       java_suspend_self();
1526 
1527       // We're done with this suspend request, but we have to loop around
1528       // and check again. Eventually we will get SR_lock without a pending
1529       // external suspend request and will be able to mark ourselves as
1530       // exiting.
1531     }
1532     // no more external suspends are allowed at this point
1533   } else {
1534     // before_exit() has already posted JVMTI THREAD_END events
1535   }
1536 
1537   // Notify waiters on thread object. This has to be done after exit() is called
1538   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1539   // group should have the destroyed bit set before waiters are notified).
1540   ensure_join(this);
1541   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1542 
1543   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1544   // held by this thread must be released.  A detach operation must only
1545   // get here if there are no Java frames on the stack.  Therefore, any
1546   // owned monitors at this point MUST be JNI-acquired monitors which are
1547   // pre-inflated and in the monitor cache.
1548   //
1549   // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1550   if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1551     assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1552     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1553     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1554   }
1555 
1556   // These things needs to be done while we are still a Java Thread. Make sure that thread
1557   // is in a consistent state, in case GC happens
1558   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1559 
1560   if (active_handles() != NULL) {
1561     JNIHandleBlock* block = active_handles();
1562     set_active_handles(NULL);
1563     JNIHandleBlock::release_block(block);
1564   }
1565 
1566   if (free_handle_block() != NULL) {
1567     JNIHandleBlock* block = free_handle_block();
1568     set_free_handle_block(NULL);
1569     JNIHandleBlock::release_block(block);
1570   }
1571 
1572   // These have to be removed while this is still a valid thread.
1573   remove_stack_guard_pages();
1574 
1575   if (UseTLAB) {
1576     tlab().make_parsable(true);  // retire TLAB
1577   }
1578 
1579   if (jvmti_thread_state() != NULL) {
1580     JvmtiExport::cleanup_thread(this);
1581   }
1582 
1583 #ifndef SERIALGC
1584   // We must flush G1-related buffers before removing a thread from
1585   // the list of active threads.
1586   if (UseG1GC) {
1587     flush_barrier_queues();
1588   }
1589 #endif
1590 
1591   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1592   Threads::remove(this);
1593 }
1594 
1595 #ifndef SERIALGC
1596 // Flush G1-related queues.
1597 void JavaThread::flush_barrier_queues() {
1598   satb_mark_queue().flush();
1599   dirty_card_queue().flush();
1600 }
1601 #endif
1602 
1603 void JavaThread::cleanup_failed_attach_current_thread() {
1604   if (get_thread_profiler() != NULL) {
1605     get_thread_profiler()->disengage();
1606     ResourceMark rm;
1607     get_thread_profiler()->print(get_thread_name());
1608   }
1609 
1610   if (active_handles() != NULL) {
1611     JNIHandleBlock* block = active_handles();
1612     set_active_handles(NULL);
1613     JNIHandleBlock::release_block(block);
1614   }
1615 
1616   if (free_handle_block() != NULL) {
1617     JNIHandleBlock* block = free_handle_block();
1618     set_free_handle_block(NULL);
1619     JNIHandleBlock::release_block(block);
1620   }
1621 
1622   if (UseTLAB) {
1623     tlab().make_parsable(true);  // retire TLAB, if any
1624   }
1625 
1626 #ifndef SERIALGC
1627   if (UseG1GC) {
1628     flush_barrier_queues();
1629   }
1630 #endif
1631 
1632   Threads::remove(this);
1633   delete this;
1634 }
1635 
1636 
1637 
1638 
1639 JavaThread* JavaThread::active() {
1640   Thread* thread = ThreadLocalStorage::thread();
1641   assert(thread != NULL, "just checking");
1642   if (thread->is_Java_thread()) {
1643     return (JavaThread*) thread;
1644   } else {
1645     assert(thread->is_VM_thread(), "this must be a vm thread");
1646     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1647     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1648     assert(ret->is_Java_thread(), "must be a Java thread");
1649     return ret;
1650   }
1651 }
1652 
1653 bool JavaThread::is_lock_owned(address adr) const {
1654   if (Thread::is_lock_owned(adr)) return true;
1655 
1656   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1657     if (chunk->contains(adr)) return true;
1658   }
1659 
1660   return false;
1661 }
1662 
1663 
1664 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1665   chunk->set_next(monitor_chunks());
1666   set_monitor_chunks(chunk);
1667 }
1668 
1669 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1670   guarantee(monitor_chunks() != NULL, "must be non empty");
1671   if (monitor_chunks() == chunk) {
1672     set_monitor_chunks(chunk->next());
1673   } else {
1674     MonitorChunk* prev = monitor_chunks();
1675     while (prev->next() != chunk) prev = prev->next();
1676     prev->set_next(chunk->next());
1677   }
1678 }
1679 
1680 // JVM support.
1681 
1682 // Note: this function shouldn't block if it's called in
1683 // _thread_in_native_trans state (such as from
1684 // check_special_condition_for_native_trans()).
1685 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1686 
1687   if (has_last_Java_frame() && has_async_condition()) {
1688     // If we are at a polling page safepoint (not a poll return)
1689     // then we must defer async exception because live registers
1690     // will be clobbered by the exception path. Poll return is
1691     // ok because the call we a returning from already collides
1692     // with exception handling registers and so there is no issue.
1693     // (The exception handling path kills call result registers but
1694     //  this is ok since the exception kills the result anyway).
1695 
1696     if (is_at_poll_safepoint()) {
1697       // if the code we are returning to has deoptimized we must defer
1698       // the exception otherwise live registers get clobbered on the
1699       // exception path before deoptimization is able to retrieve them.
1700       //
1701       RegisterMap map(this, false);
1702       frame caller_fr = last_frame().sender(&map);
1703       assert(caller_fr.is_compiled_frame(), "what?");
1704       if (caller_fr.is_deoptimized_frame()) {
1705         if (TraceExceptions) {
1706           ResourceMark rm;
1707           tty->print_cr("deferred async exception at compiled safepoint");
1708         }
1709         return;
1710       }
1711     }
1712   }
1713 
1714   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1715   if (condition == _no_async_condition) {
1716     // Conditions have changed since has_special_runtime_exit_condition()
1717     // was called:
1718     // - if we were here only because of an external suspend request,
1719     //   then that was taken care of above (or cancelled) so we are done
1720     // - if we were here because of another async request, then it has
1721     //   been cleared between the has_special_runtime_exit_condition()
1722     //   and now so again we are done
1723     return;
1724   }
1725 
1726   // Check for pending async. exception
1727   if (_pending_async_exception != NULL) {
1728     // Only overwrite an already pending exception, if it is not a threadDeath.
1729     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) {
1730 
1731       // We cannot call Exceptions::_throw(...) here because we cannot block
1732       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1733 
1734       if (TraceExceptions) {
1735         ResourceMark rm;
1736         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1737         if (has_last_Java_frame() ) {
1738           frame f = last_frame();
1739           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1740         }
1741         tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1742       }
1743       _pending_async_exception = NULL;
1744       clear_has_async_exception();
1745     }
1746   }
1747 
1748   if (check_unsafe_error &&
1749       condition == _async_unsafe_access_error && !has_pending_exception()) {
1750     condition = _no_async_condition;  // done
1751     switch (thread_state()) {
1752     case _thread_in_vm:
1753       {
1754         JavaThread* THREAD = this;
1755         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1756       }
1757     case _thread_in_native:
1758       {
1759         ThreadInVMfromNative tiv(this);
1760         JavaThread* THREAD = this;
1761         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1762       }
1763     case _thread_in_Java:
1764       {
1765         ThreadInVMfromJava tiv(this);
1766         JavaThread* THREAD = this;
1767         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1768       }
1769     default:
1770       ShouldNotReachHere();
1771     }
1772   }
1773 
1774   assert(condition == _no_async_condition || has_pending_exception() ||
1775          (!check_unsafe_error && condition == _async_unsafe_access_error),
1776          "must have handled the async condition, if no exception");
1777 }
1778 
1779 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1780   //
1781   // Check for pending external suspend. Internal suspend requests do
1782   // not use handle_special_runtime_exit_condition().
1783   // If JNIEnv proxies are allowed, don't self-suspend if the target
1784   // thread is not the current thread. In older versions of jdbx, jdbx
1785   // threads could call into the VM with another thread's JNIEnv so we
1786   // can be here operating on behalf of a suspended thread (4432884).
1787   bool do_self_suspend = is_external_suspend_with_lock();
1788   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1789     //
1790     // Because thread is external suspended the safepoint code will count
1791     // thread as at a safepoint. This can be odd because we can be here
1792     // as _thread_in_Java which would normally transition to _thread_blocked
1793     // at a safepoint. We would like to mark the thread as _thread_blocked
1794     // before calling java_suspend_self like all other callers of it but
1795     // we must then observe proper safepoint protocol. (We can't leave
1796     // _thread_blocked with a safepoint in progress). However we can be
1797     // here as _thread_in_native_trans so we can't use a normal transition
1798     // constructor/destructor pair because they assert on that type of
1799     // transition. We could do something like:
1800     //
1801     // JavaThreadState state = thread_state();
1802     // set_thread_state(_thread_in_vm);
1803     // {
1804     //   ThreadBlockInVM tbivm(this);
1805     //   java_suspend_self()
1806     // }
1807     // set_thread_state(_thread_in_vm_trans);
1808     // if (safepoint) block;
1809     // set_thread_state(state);
1810     //
1811     // but that is pretty messy. Instead we just go with the way the
1812     // code has worked before and note that this is the only path to
1813     // java_suspend_self that doesn't put the thread in _thread_blocked
1814     // mode.
1815 
1816     frame_anchor()->make_walkable(this);
1817     java_suspend_self();
1818 
1819     // We might be here for reasons in addition to the self-suspend request
1820     // so check for other async requests.
1821   }
1822 
1823   if (check_asyncs) {
1824     check_and_handle_async_exceptions();
1825   }
1826 }
1827 
1828 void JavaThread::send_thread_stop(oop java_throwable)  {
1829   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1830   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1831   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1832 
1833   // Do not throw asynchronous exceptions against the compiler thread
1834   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1835   if (is_Compiler_thread()) return;
1836 
1837   // This is a change from JDK 1.1, but JDK 1.2 will also do it:
1838   if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) {
1839     java_lang_Thread::set_stillborn(threadObj());
1840   }
1841 
1842   {
1843     // Actually throw the Throwable against the target Thread - however
1844     // only if there is no thread death exception installed already.
1845     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) {
1846       // If the topmost frame is a runtime stub, then we are calling into
1847       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1848       // must deoptimize the caller before continuing, as the compiled  exception handler table
1849       // may not be valid
1850       if (has_last_Java_frame()) {
1851         frame f = last_frame();
1852         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1853           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
1854           RegisterMap reg_map(this, UseBiasedLocking);
1855           frame compiled_frame = f.sender(&reg_map);
1856           if (compiled_frame.can_be_deoptimized()) {
1857             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
1858           }
1859         }
1860       }
1861 
1862       // Set async. pending exception in thread.
1863       set_pending_async_exception(java_throwable);
1864 
1865       if (TraceExceptions) {
1866        ResourceMark rm;
1867        tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1868       }
1869       // for AbortVMOnException flag
1870       NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
1871     }
1872   }
1873 
1874 
1875   // Interrupt thread so it will wake up from a potential wait()
1876   Thread::interrupt(this);
1877 }
1878 
1879 // External suspension mechanism.
1880 //
1881 // Tell the VM to suspend a thread when ever it knows that it does not hold on
1882 // to any VM_locks and it is at a transition
1883 // Self-suspension will happen on the transition out of the vm.
1884 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
1885 //
1886 // Guarantees on return:
1887 //   + Target thread will not execute any new bytecode (that's why we need to
1888 //     force a safepoint)
1889 //   + Target thread will not enter any new monitors
1890 //
1891 void JavaThread::java_suspend() {
1892   { MutexLocker mu(Threads_lock);
1893     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
1894        return;
1895     }
1896   }
1897 
1898   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1899     if (!is_external_suspend()) {
1900       // a racing resume has cancelled us; bail out now
1901       return;
1902     }
1903 
1904     // suspend is done
1905     uint32_t debug_bits = 0;
1906     // Warning: is_ext_suspend_completed() may temporarily drop the
1907     // SR_lock to allow the thread to reach a stable thread state if
1908     // it is currently in a transient thread state.
1909     if (is_ext_suspend_completed(false /* !called_by_wait */,
1910                                  SuspendRetryDelay, &debug_bits) ) {
1911       return;
1912     }
1913   }
1914 
1915   VM_ForceSafepoint vm_suspend;
1916   VMThread::execute(&vm_suspend);
1917 }
1918 
1919 // Part II of external suspension.
1920 // A JavaThread self suspends when it detects a pending external suspend
1921 // request. This is usually on transitions. It is also done in places
1922 // where continuing to the next transition would surprise the caller,
1923 // e.g., monitor entry.
1924 //
1925 // Returns the number of times that the thread self-suspended.
1926 //
1927 // Note: DO NOT call java_suspend_self() when you just want to block current
1928 //       thread. java_suspend_self() is the second stage of cooperative
1929 //       suspension for external suspend requests and should only be used
1930 //       to complete an external suspend request.
1931 //
1932 int JavaThread::java_suspend_self() {
1933   int ret = 0;
1934 
1935   // we are in the process of exiting so don't suspend
1936   if (is_exiting()) {
1937      clear_external_suspend();
1938      return ret;
1939   }
1940 
1941   assert(_anchor.walkable() ||
1942     (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
1943     "must have walkable stack");
1944 
1945   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1946 
1947   assert(!this->is_ext_suspended(),
1948     "a thread trying to self-suspend should not already be suspended");
1949 
1950   if (this->is_suspend_equivalent()) {
1951     // If we are self-suspending as a result of the lifting of a
1952     // suspend equivalent condition, then the suspend_equivalent
1953     // flag is not cleared until we set the ext_suspended flag so
1954     // that wait_for_ext_suspend_completion() returns consistent
1955     // results.
1956     this->clear_suspend_equivalent();
1957   }
1958 
1959   // A racing resume may have cancelled us before we grabbed SR_lock
1960   // above. Or another external suspend request could be waiting for us
1961   // by the time we return from SR_lock()->wait(). The thread
1962   // that requested the suspension may already be trying to walk our
1963   // stack and if we return now, we can change the stack out from under
1964   // it. This would be a "bad thing (TM)" and cause the stack walker
1965   // to crash. We stay self-suspended until there are no more pending
1966   // external suspend requests.
1967   while (is_external_suspend()) {
1968     ret++;
1969     this->set_ext_suspended();
1970 
1971     // _ext_suspended flag is cleared by java_resume()
1972     while (is_ext_suspended()) {
1973       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
1974     }
1975   }
1976 
1977   return ret;
1978 }
1979 
1980 #ifdef ASSERT
1981 // verify the JavaThread has not yet been published in the Threads::list, and
1982 // hence doesn't need protection from concurrent access at this stage
1983 void JavaThread::verify_not_published() {
1984   if (!Threads_lock->owned_by_self()) {
1985    MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
1986    assert( !Threads::includes(this),
1987            "java thread shouldn't have been published yet!");
1988   }
1989   else {
1990    assert( !Threads::includes(this),
1991            "java thread shouldn't have been published yet!");
1992   }
1993 }
1994 #endif
1995 
1996 // Slow path when the native==>VM/Java barriers detect a safepoint is in
1997 // progress or when _suspend_flags is non-zero.
1998 // Current thread needs to self-suspend if there is a suspend request and/or
1999 // block if a safepoint is in progress.
2000 // Async exception ISN'T checked.
2001 // Note only the ThreadInVMfromNative transition can call this function
2002 // directly and when thread state is _thread_in_native_trans
2003 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2004   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2005 
2006   JavaThread *curJT = JavaThread::current();
2007   bool do_self_suspend = thread->is_external_suspend();
2008 
2009   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2010 
2011   // If JNIEnv proxies are allowed, don't self-suspend if the target
2012   // thread is not the current thread. In older versions of jdbx, jdbx
2013   // threads could call into the VM with another thread's JNIEnv so we
2014   // can be here operating on behalf of a suspended thread (4432884).
2015   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2016     JavaThreadState state = thread->thread_state();
2017 
2018     // We mark this thread_blocked state as a suspend-equivalent so
2019     // that a caller to is_ext_suspend_completed() won't be confused.
2020     // The suspend-equivalent state is cleared by java_suspend_self().
2021     thread->set_suspend_equivalent();
2022 
2023     // If the safepoint code sees the _thread_in_native_trans state, it will
2024     // wait until the thread changes to other thread state. There is no
2025     // guarantee on how soon we can obtain the SR_lock and complete the
2026     // self-suspend request. It would be a bad idea to let safepoint wait for
2027     // too long. Temporarily change the state to _thread_blocked to
2028     // let the VM thread know that this thread is ready for GC. The problem
2029     // of changing thread state is that safepoint could happen just after
2030     // java_suspend_self() returns after being resumed, and VM thread will
2031     // see the _thread_blocked state. We must check for safepoint
2032     // after restoring the state and make sure we won't leave while a safepoint
2033     // is in progress.
2034     thread->set_thread_state(_thread_blocked);
2035     thread->java_suspend_self();
2036     thread->set_thread_state(state);
2037     // Make sure new state is seen by VM thread
2038     if (os::is_MP()) {
2039       if (UseMembar) {
2040         // Force a fence between the write above and read below
2041         OrderAccess::fence();
2042       } else {
2043         // Must use this rather than serialization page in particular on Windows
2044         InterfaceSupport::serialize_memory(thread);
2045       }
2046     }
2047   }
2048 
2049   if (SafepointSynchronize::do_call_back()) {
2050     // If we are safepointing, then block the caller which may not be
2051     // the same as the target thread (see above).
2052     SafepointSynchronize::block(curJT);
2053   }
2054 
2055   if (thread->is_deopt_suspend()) {
2056     thread->clear_deopt_suspend();
2057     RegisterMap map(thread, false);
2058     frame f = thread->last_frame();
2059     while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2060       f = f.sender(&map);
2061     }
2062     if (f.id() == thread->must_deopt_id()) {
2063       thread->clear_must_deopt_id();
2064       // Since we know we're safe to deopt the current state is a safe state
2065       f.deoptimize(thread, true);
2066     } else {
2067       fatal("missed deoptimization!");
2068     }
2069   }
2070 }
2071 
2072 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2073 // progress or when _suspend_flags is non-zero.
2074 // Current thread needs to self-suspend if there is a suspend request and/or
2075 // block if a safepoint is in progress.
2076 // Also check for pending async exception (not including unsafe access error).
2077 // Note only the native==>VM/Java barriers can call this function and when
2078 // thread state is _thread_in_native_trans.
2079 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2080   check_safepoint_and_suspend_for_native_trans(thread);
2081 
2082   if (thread->has_async_exception()) {
2083     // We are in _thread_in_native_trans state, don't handle unsafe
2084     // access error since that may block.
2085     thread->check_and_handle_async_exceptions(false);
2086   }
2087 }
2088 
2089 // We need to guarantee the Threads_lock here, since resumes are not
2090 // allowed during safepoint synchronization
2091 // Can only resume from an external suspension
2092 void JavaThread::java_resume() {
2093   assert_locked_or_safepoint(Threads_lock);
2094 
2095   // Sanity check: thread is gone, has started exiting or the thread
2096   // was not externally suspended.
2097   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2098     return;
2099   }
2100 
2101   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2102 
2103   clear_external_suspend();
2104 
2105   if (is_ext_suspended()) {
2106     clear_ext_suspended();
2107     SR_lock()->notify_all();
2108   }
2109 }
2110 
2111 void JavaThread::create_stack_guard_pages() {
2112   if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2113   address low_addr = stack_base() - stack_size();
2114   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2115 
2116   int allocate = os::allocate_stack_guard_pages();
2117   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2118 
2119   if (allocate && !os::commit_memory((char *) low_addr, len)) {
2120     warning("Attempt to allocate stack guard pages failed.");
2121     return;
2122   }
2123 
2124   if (os::guard_memory((char *) low_addr, len)) {
2125     _stack_guard_state = stack_guard_enabled;
2126   } else {
2127     warning("Attempt to protect stack guard pages failed.");
2128     if (os::uncommit_memory((char *) low_addr, len)) {
2129       warning("Attempt to deallocate stack guard pages failed.");
2130     }
2131   }
2132 }
2133 
2134 void JavaThread::remove_stack_guard_pages() {
2135   if (_stack_guard_state == stack_guard_unused) return;
2136   address low_addr = stack_base() - stack_size();
2137   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2138 
2139   if (os::allocate_stack_guard_pages()) {
2140     if (os::uncommit_memory((char *) low_addr, len)) {
2141       _stack_guard_state = stack_guard_unused;
2142     } else {
2143       warning("Attempt to deallocate stack guard pages failed.");
2144     }
2145   } else {
2146     if (_stack_guard_state == stack_guard_unused) return;
2147     if (os::unguard_memory((char *) low_addr, len)) {
2148       _stack_guard_state = stack_guard_unused;
2149     } else {
2150         warning("Attempt to unprotect stack guard pages failed.");
2151     }
2152   }
2153 }
2154 
2155 void JavaThread::enable_stack_yellow_zone() {
2156   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2157   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2158 
2159   // The base notation is from the stacks point of view, growing downward.
2160   // We need to adjust it to work correctly with guard_memory()
2161   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2162 
2163   guarantee(base < stack_base(),"Error calculating stack yellow zone");
2164   guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2165 
2166   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2167     _stack_guard_state = stack_guard_enabled;
2168   } else {
2169     warning("Attempt to guard stack yellow zone failed.");
2170   }
2171   enable_register_stack_guard();
2172 }
2173 
2174 void JavaThread::disable_stack_yellow_zone() {
2175   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2176   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2177 
2178   // Simply return if called for a thread that does not use guard pages.
2179   if (_stack_guard_state == stack_guard_unused) return;
2180 
2181   // The base notation is from the stacks point of view, growing downward.
2182   // We need to adjust it to work correctly with guard_memory()
2183   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2184 
2185   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2186     _stack_guard_state = stack_guard_yellow_disabled;
2187   } else {
2188     warning("Attempt to unguard stack yellow zone failed.");
2189   }
2190   disable_register_stack_guard();
2191 }
2192 
2193 void JavaThread::enable_stack_red_zone() {
2194   // The base notation is from the stacks point of view, growing downward.
2195   // We need to adjust it to work correctly with guard_memory()
2196   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2197   address base = stack_red_zone_base() - stack_red_zone_size();
2198 
2199   guarantee(base < stack_base(),"Error calculating stack red zone");
2200   guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2201 
2202   if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2203     warning("Attempt to guard stack red zone failed.");
2204   }
2205 }
2206 
2207 void JavaThread::disable_stack_red_zone() {
2208   // The base notation is from the stacks point of view, growing downward.
2209   // We need to adjust it to work correctly with guard_memory()
2210   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2211   address base = stack_red_zone_base() - stack_red_zone_size();
2212   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2213     warning("Attempt to unguard stack red zone failed.");
2214   }
2215 }
2216 
2217 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2218   // ignore is there is no stack
2219   if (!has_last_Java_frame()) return;
2220   // traverse the stack frames. Starts from top frame.
2221   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2222     frame* fr = fst.current();
2223     f(fr, fst.register_map());
2224   }
2225 }
2226 
2227 
2228 #ifndef PRODUCT
2229 // Deoptimization
2230 // Function for testing deoptimization
2231 void JavaThread::deoptimize() {
2232   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2233   StackFrameStream fst(this, UseBiasedLocking);
2234   bool deopt = false;           // Dump stack only if a deopt actually happens.
2235   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2236   // Iterate over all frames in the thread and deoptimize
2237   for(; !fst.is_done(); fst.next()) {
2238     if(fst.current()->can_be_deoptimized()) {
2239 
2240       if (only_at) {
2241         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2242         // consists of comma or carriage return separated numbers so
2243         // search for the current bci in that string.
2244         address pc = fst.current()->pc();
2245         nmethod* nm =  (nmethod*) fst.current()->cb();
2246         ScopeDesc* sd = nm->scope_desc_at( pc);
2247         char buffer[8];
2248         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2249         size_t len = strlen(buffer);
2250         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2251         while (found != NULL) {
2252           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2253               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2254             // Check that the bci found is bracketed by terminators.
2255             break;
2256           }
2257           found = strstr(found + 1, buffer);
2258         }
2259         if (!found) {
2260           continue;
2261         }
2262       }
2263 
2264       if (DebugDeoptimization && !deopt) {
2265         deopt = true; // One-time only print before deopt
2266         tty->print_cr("[BEFORE Deoptimization]");
2267         trace_frames();
2268         trace_stack();
2269       }
2270       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2271     }
2272   }
2273 
2274   if (DebugDeoptimization && deopt) {
2275     tty->print_cr("[AFTER Deoptimization]");
2276     trace_frames();
2277   }
2278 }
2279 
2280 
2281 // Make zombies
2282 void JavaThread::make_zombies() {
2283   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2284     if (fst.current()->can_be_deoptimized()) {
2285       // it is a Java nmethod
2286       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2287       nm->make_not_entrant();
2288     }
2289   }
2290 }
2291 #endif // PRODUCT
2292 
2293 
2294 void JavaThread::deoptimized_wrt_marked_nmethods() {
2295   if (!has_last_Java_frame()) return;
2296   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2297   StackFrameStream fst(this, UseBiasedLocking);
2298   for(; !fst.is_done(); fst.next()) {
2299     if (fst.current()->should_be_deoptimized()) {
2300       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2301     }
2302   }
2303 }
2304 
2305 
2306 // GC support
2307 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2308 
2309 void JavaThread::gc_epilogue() {
2310   frames_do(frame_gc_epilogue);
2311 }
2312 
2313 
2314 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2315 
2316 void JavaThread::gc_prologue() {
2317   frames_do(frame_gc_prologue);
2318 }
2319 
2320 
2321 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2322   // Flush deferred store-barriers, if any, associated with
2323   // initializing stores done by this JavaThread in the current epoch.
2324   Universe::heap()->flush_deferred_store_barrier(this);
2325 
2326   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2327   // since there may be more than one thread using each ThreadProfiler.
2328 
2329   // Traverse the GCHandles
2330   Thread::oops_do(f, cf);
2331 
2332   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2333           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2334 
2335   if (has_last_Java_frame()) {
2336 
2337     // Traverse the privileged stack
2338     if (_privileged_stack_top != NULL) {
2339       _privileged_stack_top->oops_do(f);
2340     }
2341 
2342     // traverse the registered growable array
2343     if (_array_for_gc != NULL) {
2344       for (int index = 0; index < _array_for_gc->length(); index++) {
2345         f->do_oop(_array_for_gc->adr_at(index));
2346       }
2347     }
2348 
2349     // Traverse the monitor chunks
2350     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2351       chunk->oops_do(f);
2352     }
2353 
2354     // Traverse the execution stack
2355     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2356       fst.current()->oops_do(f, cf, fst.register_map());
2357     }
2358   }
2359 
2360   // callee_target is never live across a gc point so NULL it here should
2361   // it still contain a methdOop.
2362 
2363   set_callee_target(NULL);
2364 
2365   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2366   // If we have deferred set_locals there might be oops waiting to be
2367   // written
2368   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2369   if (list != NULL) {
2370     for (int i = 0; i < list->length(); i++) {
2371       list->at(i)->oops_do(f);
2372     }
2373   }
2374 
2375   // Traverse instance variables at the end since the GC may be moving things
2376   // around using this function
2377   f->do_oop((oop*) &_threadObj);
2378   f->do_oop((oop*) &_vm_result);
2379   f->do_oop((oop*) &_vm_result_2);
2380   f->do_oop((oop*) &_exception_oop);
2381   f->do_oop((oop*) &_pending_async_exception);
2382 
2383   if (jvmti_thread_state() != NULL) {
2384     jvmti_thread_state()->oops_do(f);
2385   }
2386 }
2387 
2388 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2389   Thread::nmethods_do(cf);  // (super method is a no-op)
2390 
2391   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2392           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2393 
2394   if (has_last_Java_frame()) {
2395     // Traverse the execution stack
2396     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2397       fst.current()->nmethods_do(cf);
2398     }
2399   }
2400 }
2401 
2402 // Printing
2403 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2404   switch (_thread_state) {
2405   case _thread_uninitialized:     return "_thread_uninitialized";
2406   case _thread_new:               return "_thread_new";
2407   case _thread_new_trans:         return "_thread_new_trans";
2408   case _thread_in_native:         return "_thread_in_native";
2409   case _thread_in_native_trans:   return "_thread_in_native_trans";
2410   case _thread_in_vm:             return "_thread_in_vm";
2411   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2412   case _thread_in_Java:           return "_thread_in_Java";
2413   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2414   case _thread_blocked:           return "_thread_blocked";
2415   case _thread_blocked_trans:     return "_thread_blocked_trans";
2416   default:                        return "unknown thread state";
2417   }
2418 }
2419 
2420 #ifndef PRODUCT
2421 void JavaThread::print_thread_state_on(outputStream *st) const {
2422   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2423 };
2424 void JavaThread::print_thread_state() const {
2425   print_thread_state_on(tty);
2426 };
2427 #endif // PRODUCT
2428 
2429 // Called by Threads::print() for VM_PrintThreads operation
2430 void JavaThread::print_on(outputStream *st) const {
2431   st->print("\"%s\" ", get_thread_name());
2432   oop thread_oop = threadObj();
2433   if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2434   Thread::print_on(st);
2435   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2436   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2437   if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2438     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2439   }
2440 #ifndef PRODUCT
2441   print_thread_state_on(st);
2442   _safepoint_state->print_on(st);
2443 #endif // PRODUCT
2444 }
2445 
2446 // Called by fatal error handler. The difference between this and
2447 // JavaThread::print() is that we can't grab lock or allocate memory.
2448 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2449   st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
2450   oop thread_obj = threadObj();
2451   if (thread_obj != NULL) {
2452      if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2453   }
2454   st->print(" [");
2455   st->print("%s", _get_thread_state_name(_thread_state));
2456   if (osthread()) {
2457     st->print(", id=%d", osthread()->thread_id());
2458   }
2459   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2460             _stack_base - _stack_size, _stack_base);
2461   st->print("]");
2462   return;
2463 }
2464 
2465 // Verification
2466 
2467 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2468 
2469 void JavaThread::verify() {
2470   // Verify oops in the thread.
2471   oops_do(&VerifyOopClosure::verify_oop, NULL);
2472 
2473   // Verify the stack frames.
2474   frames_do(frame_verify);
2475 }
2476 
2477 // CR 6300358 (sub-CR 2137150)
2478 // Most callers of this method assume that it can't return NULL but a
2479 // thread may not have a name whilst it is in the process of attaching to
2480 // the VM - see CR 6412693, and there are places where a JavaThread can be
2481 // seen prior to having it's threadObj set (eg JNI attaching threads and
2482 // if vm exit occurs during initialization). These cases can all be accounted
2483 // for such that this method never returns NULL.
2484 const char* JavaThread::get_thread_name() const {
2485 #ifdef ASSERT
2486   // early safepoints can hit while current thread does not yet have TLS
2487   if (!SafepointSynchronize::is_at_safepoint()) {
2488     Thread *cur = Thread::current();
2489     if (!(cur->is_Java_thread() && cur == this)) {
2490       // Current JavaThreads are allowed to get their own name without
2491       // the Threads_lock.
2492       assert_locked_or_safepoint(Threads_lock);
2493     }
2494   }
2495 #endif // ASSERT
2496     return get_thread_name_string();
2497 }
2498 
2499 // Returns a non-NULL representation of this thread's name, or a suitable
2500 // descriptive string if there is no set name
2501 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2502   const char* name_str;
2503   oop thread_obj = threadObj();
2504   if (thread_obj != NULL) {
2505     typeArrayOop name = java_lang_Thread::name(thread_obj);
2506     if (name != NULL) {
2507       if (buf == NULL) {
2508         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2509       }
2510       else {
2511         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2512       }
2513     }
2514     else if (is_attaching()) { // workaround for 6412693 - see 6404306
2515       name_str = "<no-name - thread is attaching>";
2516     }
2517     else {
2518       name_str = Thread::name();
2519     }
2520   }
2521   else {
2522     name_str = Thread::name();
2523   }
2524   assert(name_str != NULL, "unexpected NULL thread name");
2525   return name_str;
2526 }
2527 
2528 
2529 const char* JavaThread::get_threadgroup_name() const {
2530   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2531   oop thread_obj = threadObj();
2532   if (thread_obj != NULL) {
2533     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2534     if (thread_group != NULL) {
2535       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2536       // ThreadGroup.name can be null
2537       if (name != NULL) {
2538         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2539         return str;
2540       }
2541     }
2542   }
2543   return NULL;
2544 }
2545 
2546 const char* JavaThread::get_parent_name() const {
2547   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2548   oop thread_obj = threadObj();
2549   if (thread_obj != NULL) {
2550     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2551     if (thread_group != NULL) {
2552       oop parent = java_lang_ThreadGroup::parent(thread_group);
2553       if (parent != NULL) {
2554         typeArrayOop name = java_lang_ThreadGroup::name(parent);
2555         // ThreadGroup.name can be null
2556         if (name != NULL) {
2557           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2558           return str;
2559         }
2560       }
2561     }
2562   }
2563   return NULL;
2564 }
2565 
2566 ThreadPriority JavaThread::java_priority() const {
2567   oop thr_oop = threadObj();
2568   if (thr_oop == NULL) return NormPriority; // Bootstrapping
2569   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2570   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2571   return priority;
2572 }
2573 
2574 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2575 
2576   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2577   // Link Java Thread object <-> C++ Thread
2578 
2579   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2580   // and put it into a new Handle.  The Handle "thread_oop" can then
2581   // be used to pass the C++ thread object to other methods.
2582 
2583   // Set the Java level thread object (jthread) field of the
2584   // new thread (a JavaThread *) to C++ thread object using the
2585   // "thread_oop" handle.
2586 
2587   // Set the thread field (a JavaThread *) of the
2588   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2589 
2590   Handle thread_oop(Thread::current(),
2591                     JNIHandles::resolve_non_null(jni_thread));
2592   assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2593     "must be initialized");
2594   set_threadObj(thread_oop());
2595   java_lang_Thread::set_thread(thread_oop(), this);
2596 
2597   if (prio == NoPriority) {
2598     prio = java_lang_Thread::priority(thread_oop());
2599     assert(prio != NoPriority, "A valid priority should be present");
2600   }
2601 
2602   // Push the Java priority down to the native thread; needs Threads_lock
2603   Thread::set_priority(this, prio);
2604 
2605   // Add the new thread to the Threads list and set it in motion.
2606   // We must have threads lock in order to call Threads::add.
2607   // It is crucial that we do not block before the thread is
2608   // added to the Threads list for if a GC happens, then the java_thread oop
2609   // will not be visited by GC.
2610   Threads::add(this);
2611 }
2612 
2613 oop JavaThread::current_park_blocker() {
2614   // Support for JSR-166 locks
2615   oop thread_oop = threadObj();
2616   if (thread_oop != NULL &&
2617       JDK_Version::current().supports_thread_park_blocker()) {
2618     return java_lang_Thread::park_blocker(thread_oop);
2619   }
2620   return NULL;
2621 }
2622 
2623 
2624 void JavaThread::print_stack_on(outputStream* st) {
2625   if (!has_last_Java_frame()) return;
2626   ResourceMark rm;
2627   HandleMark   hm;
2628 
2629   RegisterMap reg_map(this);
2630   vframe* start_vf = last_java_vframe(&reg_map);
2631   int count = 0;
2632   for (vframe* f = start_vf; f; f = f->sender() ) {
2633     if (f->is_java_frame()) {
2634       javaVFrame* jvf = javaVFrame::cast(f);
2635       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2636 
2637       // Print out lock information
2638       if (JavaMonitorsInStackTrace) {
2639         jvf->print_lock_info_on(st, count);
2640       }
2641     } else {
2642       // Ignore non-Java frames
2643     }
2644 
2645     // Bail-out case for too deep stacks
2646     count++;
2647     if (MaxJavaStackTraceDepth == count) return;
2648   }
2649 }
2650 
2651 
2652 // JVMTI PopFrame support
2653 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2654   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2655   if (in_bytes(size_in_bytes) != 0) {
2656     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2657     _popframe_preserved_args_size = in_bytes(size_in_bytes);
2658     Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2659   }
2660 }
2661 
2662 void* JavaThread::popframe_preserved_args() {
2663   return _popframe_preserved_args;
2664 }
2665 
2666 ByteSize JavaThread::popframe_preserved_args_size() {
2667   return in_ByteSize(_popframe_preserved_args_size);
2668 }
2669 
2670 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2671   int sz = in_bytes(popframe_preserved_args_size());
2672   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2673   return in_WordSize(sz / wordSize);
2674 }
2675 
2676 void JavaThread::popframe_free_preserved_args() {
2677   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2678   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2679   _popframe_preserved_args = NULL;
2680   _popframe_preserved_args_size = 0;
2681 }
2682 
2683 #ifndef PRODUCT
2684 
2685 void JavaThread::trace_frames() {
2686   tty->print_cr("[Describe stack]");
2687   int frame_no = 1;
2688   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2689     tty->print("  %d. ", frame_no++);
2690     fst.current()->print_value_on(tty,this);
2691     tty->cr();
2692   }
2693 }
2694 
2695 
2696 void JavaThread::trace_stack_from(vframe* start_vf) {
2697   ResourceMark rm;
2698   int vframe_no = 1;
2699   for (vframe* f = start_vf; f; f = f->sender() ) {
2700     if (f->is_java_frame()) {
2701       javaVFrame::cast(f)->print_activation(vframe_no++);
2702     } else {
2703       f->print();
2704     }
2705     if (vframe_no > StackPrintLimit) {
2706       tty->print_cr("...<more frames>...");
2707       return;
2708     }
2709   }
2710 }
2711 
2712 
2713 void JavaThread::trace_stack() {
2714   if (!has_last_Java_frame()) return;
2715   ResourceMark rm;
2716   HandleMark   hm;
2717   RegisterMap reg_map(this);
2718   trace_stack_from(last_java_vframe(&reg_map));
2719 }
2720 
2721 
2722 #endif // PRODUCT
2723 
2724 
2725 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2726   assert(reg_map != NULL, "a map must be given");
2727   frame f = last_frame();
2728   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2729     if (vf->is_java_frame()) return javaVFrame::cast(vf);
2730   }
2731   return NULL;
2732 }
2733 
2734 
2735 klassOop JavaThread::security_get_caller_class(int depth) {
2736   vframeStream vfst(this);
2737   vfst.security_get_caller_frame(depth);
2738   if (!vfst.at_end()) {
2739     return vfst.method()->method_holder();
2740   }
2741   return NULL;
2742 }
2743 
2744 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2745   assert(thread->is_Compiler_thread(), "must be compiler thread");
2746   CompileBroker::compiler_thread_loop();
2747 }
2748 
2749 // Create a CompilerThread
2750 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2751 : JavaThread(&compiler_thread_entry) {
2752   _env   = NULL;
2753   _log   = NULL;
2754   _task  = NULL;
2755   _queue = queue;
2756   _counters = counters;
2757 
2758 #ifndef PRODUCT
2759   _ideal_graph_printer = NULL;
2760 #endif
2761 }
2762 
2763 
2764 // ======= Threads ========
2765 
2766 // The Threads class links together all active threads, and provides
2767 // operations over all threads.  It is protected by its own Mutex
2768 // lock, which is also used in other contexts to protect thread
2769 // operations from having the thread being operated on from exiting
2770 // and going away unexpectedly (e.g., safepoint synchronization)
2771 
2772 JavaThread* Threads::_thread_list = NULL;
2773 int         Threads::_number_of_threads = 0;
2774 int         Threads::_number_of_non_daemon_threads = 0;
2775 int         Threads::_return_code = 0;
2776 size_t      JavaThread::_stack_size_at_create = 0;
2777 
2778 // All JavaThreads
2779 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2780 
2781 void os_stream();
2782 
2783 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2784 void Threads::threads_do(ThreadClosure* tc) {
2785   assert_locked_or_safepoint(Threads_lock);
2786   // ALL_JAVA_THREADS iterates through all JavaThreads
2787   ALL_JAVA_THREADS(p) {
2788     tc->do_thread(p);
2789   }
2790   // Someday we could have a table or list of all non-JavaThreads.
2791   // For now, just manually iterate through them.
2792   tc->do_thread(VMThread::vm_thread());
2793   Universe::heap()->gc_threads_do(tc);
2794   WatcherThread *wt = WatcherThread::watcher_thread();
2795   // Strictly speaking, the following NULL check isn't sufficient to make sure
2796   // the data for WatcherThread is still valid upon being examined. However,
2797   // considering that WatchThread terminates when the VM is on the way to
2798   // exit at safepoint, the chance of the above is extremely small. The right
2799   // way to prevent termination of WatcherThread would be to acquire
2800   // Terminator_lock, but we can't do that without violating the lock rank
2801   // checking in some cases.
2802   if (wt != NULL)
2803     tc->do_thread(wt);
2804 
2805   // If CompilerThreads ever become non-JavaThreads, add them here
2806 }
2807 
2808 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2809 
2810   extern void JDK_Version_init();
2811 
2812   // Check version
2813   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2814 
2815   // Initialize the output stream module
2816   ostream_init();
2817 
2818   // Process java launcher properties.
2819   Arguments::process_sun_java_launcher_properties(args);
2820 
2821   // Initialize the os module before using TLS
2822   os::init();
2823 
2824   // Initialize system properties.
2825   Arguments::init_system_properties();
2826 
2827   // So that JDK version can be used as a discrimintor when parsing arguments
2828   JDK_Version_init();
2829 
2830   // Parse arguments
2831   jint parse_result = Arguments::parse(args);
2832   if (parse_result != JNI_OK) return parse_result;
2833 
2834   if (PauseAtStartup) {
2835     os::pause();
2836   }
2837 
2838   HS_DTRACE_PROBE(hotspot, vm__init__begin);
2839 
2840   // Record VM creation timing statistics
2841   TraceVmCreationTime create_vm_timer;
2842   create_vm_timer.start();
2843 
2844   // Timing (must come after argument parsing)
2845   TraceTime timer("Create VM", TraceStartupTime);
2846 
2847   // Initialize the os module after parsing the args
2848   jint os_init_2_result = os::init_2();
2849   if (os_init_2_result != JNI_OK) return os_init_2_result;
2850 
2851   // Initialize output stream logging
2852   ostream_init_log();
2853 
2854   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
2855   // Must be before create_vm_init_agents()
2856   if (Arguments::init_libraries_at_startup()) {
2857     convert_vm_init_libraries_to_agents();
2858   }
2859 
2860   // Launch -agentlib/-agentpath and converted -Xrun agents
2861   if (Arguments::init_agents_at_startup()) {
2862     create_vm_init_agents();
2863   }
2864 
2865   // Initialize Threads state
2866   _thread_list = NULL;
2867   _number_of_threads = 0;
2868   _number_of_non_daemon_threads = 0;
2869 
2870   // Initialize TLS
2871   ThreadLocalStorage::init();
2872 
2873   // Initialize global data structures and create system classes in heap
2874   vm_init_globals();
2875 
2876   // Attach the main thread to this os thread
2877   JavaThread* main_thread = new JavaThread();
2878   main_thread->set_thread_state(_thread_in_vm);
2879   // must do this before set_active_handles and initialize_thread_local_storage
2880   // Note: on solaris initialize_thread_local_storage() will (indirectly)
2881   // change the stack size recorded here to one based on the java thread
2882   // stacksize. This adjusted size is what is used to figure the placement
2883   // of the guard pages.
2884   main_thread->record_stack_base_and_size();
2885   main_thread->initialize_thread_local_storage();
2886 
2887   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
2888 
2889   if (!main_thread->set_as_starting_thread()) {
2890     vm_shutdown_during_initialization(
2891       "Failed necessary internal allocation. Out of swap space");
2892     delete main_thread;
2893     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2894     return JNI_ENOMEM;
2895   }
2896 
2897   // Enable guard page *after* os::create_main_thread(), otherwise it would
2898   // crash Linux VM, see notes in os_linux.cpp.
2899   main_thread->create_stack_guard_pages();
2900 
2901   // Initialize Java-Leve synchronization subsystem
2902   ObjectSynchronizer::Initialize() ;
2903 
2904   // Initialize global modules
2905   jint status = init_globals();
2906   if (status != JNI_OK) {
2907     delete main_thread;
2908     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
2909     return status;
2910   }
2911 
2912   HandleMark hm;
2913 
2914   { MutexLocker mu(Threads_lock);
2915     Threads::add(main_thread);
2916   }
2917 
2918   // Any JVMTI raw monitors entered in onload will transition into
2919   // real raw monitor. VM is setup enough here for raw monitor enter.
2920   JvmtiExport::transition_pending_onload_raw_monitors();
2921 
2922   if (VerifyBeforeGC &&
2923       Universe::heap()->total_collections() >= VerifyGCStartAt) {
2924     Universe::heap()->prepare_for_verify();
2925     Universe::verify();   // make sure we're starting with a clean slate
2926   }
2927 
2928   // Create the VMThread
2929   { TraceTime timer("Start VMThread", TraceStartupTime);
2930     VMThread::create();
2931     Thread* vmthread = VMThread::vm_thread();
2932 
2933     if (!os::create_thread(vmthread, os::vm_thread))
2934       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
2935 
2936     // Wait for the VM thread to become ready, and VMThread::run to initialize
2937     // Monitors can have spurious returns, must always check another state flag
2938     {
2939       MutexLocker ml(Notify_lock);
2940       os::start_thread(vmthread);
2941       while (vmthread->active_handles() == NULL) {
2942         Notify_lock->wait();
2943       }
2944     }
2945   }
2946 
2947   assert (Universe::is_fully_initialized(), "not initialized");
2948   EXCEPTION_MARK;
2949 
2950   // At this point, the Universe is initialized, but we have not executed
2951   // any byte code.  Now is a good time (the only time) to dump out the
2952   // internal state of the JVM for sharing.
2953 
2954   if (DumpSharedSpaces) {
2955     Universe::heap()->preload_and_dump(CHECK_0);
2956     ShouldNotReachHere();
2957   }
2958 
2959   // Always call even when there are not JVMTI environments yet, since environments
2960   // may be attached late and JVMTI must track phases of VM execution
2961   JvmtiExport::enter_start_phase();
2962 
2963   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
2964   JvmtiExport::post_vm_start();
2965 
2966   {
2967     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
2968 
2969     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
2970       create_vm_init_libraries();
2971     }
2972 
2973     if (InitializeJavaLangString) {
2974       initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0);
2975     } else {
2976       warning("java.lang.String not initialized");
2977     }
2978 
2979     if (AggressiveOpts) {
2980       {
2981         // Forcibly initialize java/util/HashMap and mutate the private
2982         // static final "frontCacheEnabled" field before we start creating instances
2983 #ifdef ASSERT
2984         klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2985         assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
2986 #endif
2987         klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0);
2988         KlassHandle k = KlassHandle(THREAD, k_o);
2989         guarantee(k.not_null(), "Must find java/util/HashMap");
2990         instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
2991         ik->initialize(CHECK_0);
2992         fieldDescriptor fd;
2993         // Possible we might not find this field; if so, don't break
2994         if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
2995           k()->bool_field_put(fd.offset(), true);
2996         }
2997       }
2998 
2999       if (UseStringCache) {
3000         // Forcibly initialize java/lang/StringValue and mutate the private
3001         // static final "stringCacheEnabled" field before we start creating instances
3002         klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3003         // Possible that StringValue isn't present: if so, silently don't break
3004         if (k_o != NULL) {
3005           KlassHandle k = KlassHandle(THREAD, k_o);
3006           instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3007           ik->initialize(CHECK_0);
3008           fieldDescriptor fd;
3009           // Possible we might not find this field: if so, silently don't break
3010           if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3011             k()->bool_field_put(fd.offset(), true);
3012           }
3013         }
3014       }
3015     }
3016 
3017     // Initialize java_lang.System (needed before creating the thread)
3018     if (InitializeJavaLangSystem) {
3019       initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0);
3020       initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0);
3021       Handle thread_group = create_initial_thread_group(CHECK_0);
3022       Universe::set_main_thread_group(thread_group());
3023       initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0);
3024       oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3025       main_thread->set_threadObj(thread_object);
3026       // Set thread status to running since main thread has
3027       // been started and running.
3028       java_lang_Thread::set_thread_status(thread_object,
3029                                           java_lang_Thread::RUNNABLE);
3030 
3031       // The VM preresolve methods to these classes. Make sure that get initialized
3032       initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0);
3033       initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(),  CHECK_0);
3034       // The VM creates & returns objects of this class. Make sure it's initialized.
3035       initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0);
3036       call_initializeSystemClass(CHECK_0);
3037     } else {
3038       warning("java.lang.System not initialized");
3039     }
3040 
3041     // an instance of OutOfMemory exception has been allocated earlier
3042     if (InitializeJavaLangExceptionsErrors) {
3043       initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0);
3044       initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0);
3045       initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0);
3046       initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0);
3047       initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0);
3048       initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0);
3049       initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0);
3050     } else {
3051       warning("java.lang.OutOfMemoryError has not been initialized");
3052       warning("java.lang.NullPointerException has not been initialized");
3053       warning("java.lang.ClassCastException has not been initialized");
3054       warning("java.lang.ArrayStoreException has not been initialized");
3055       warning("java.lang.ArithmeticException has not been initialized");
3056       warning("java.lang.StackOverflowError has not been initialized");
3057     }
3058 
3059     if (EnableInvokeDynamic) {
3060       // JSR 292: An intialized java.dyn.InvokeDynamic is required in
3061       // the compiler.
3062       initialize_class(vmSymbolHandles::java_dyn_InvokeDynamic(), CHECK_0);
3063     }
3064   }
3065 
3066   // See        : bugid 4211085.
3067   // Background : the static initializer of java.lang.Compiler tries to read
3068   //              property"java.compiler" and read & write property "java.vm.info".
3069   //              When a security manager is installed through the command line
3070   //              option "-Djava.security.manager", the above properties are not
3071   //              readable and the static initializer for java.lang.Compiler fails
3072   //              resulting in a NoClassDefFoundError.  This can happen in any
3073   //              user code which calls methods in java.lang.Compiler.
3074   // Hack :       the hack is to pre-load and initialize this class, so that only
3075   //              system domains are on the stack when the properties are read.
3076   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3077   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3078   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3079   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3080   //              Once that is done, we should remove this hack.
3081   initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0);
3082 
3083   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3084   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3085   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3086   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3087   // This should also be taken out as soon as 4211383 gets fixed.
3088   reset_vm_info_property(CHECK_0);
3089 
3090   quicken_jni_functions();
3091 
3092   // Set flag that basic initialization has completed. Used by exceptions and various
3093   // debug stuff, that does not work until all basic classes have been initialized.
3094   set_init_completed();
3095 
3096   HS_DTRACE_PROBE(hotspot, vm__init__end);
3097 
3098   // record VM initialization completion time
3099   Management::record_vm_init_completed();
3100 
3101   // Compute system loader. Note that this has to occur after set_init_completed, since
3102   // valid exceptions may be thrown in the process.
3103   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3104   // set_init_completed has just been called, causing exceptions not to be shortcut
3105   // anymore. We call vm_exit_during_initialization directly instead.
3106   SystemDictionary::compute_java_system_loader(THREAD);
3107   if (HAS_PENDING_EXCEPTION) {
3108     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3109   }
3110 
3111 #ifndef SERIALGC
3112   // Support for ConcurrentMarkSweep. This should be cleaned up
3113   // and better encapsulated. The ugly nested if test would go away
3114   // once things are properly refactored. XXX YSR
3115   if (UseConcMarkSweepGC || UseG1GC) {
3116     if (UseConcMarkSweepGC) {
3117       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3118     } else {
3119       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3120     }
3121     if (HAS_PENDING_EXCEPTION) {
3122       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3123     }
3124   }
3125 #endif // SERIALGC
3126 
3127   // Always call even when there are not JVMTI environments yet, since environments
3128   // may be attached late and JVMTI must track phases of VM execution
3129   JvmtiExport::enter_live_phase();
3130 
3131   // Signal Dispatcher needs to be started before VMInit event is posted
3132   os::signal_init();
3133 
3134   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3135   if (!DisableAttachMechanism) {
3136     if (StartAttachListener || AttachListener::init_at_startup()) {
3137       AttachListener::init();
3138     }
3139   }
3140 
3141   // Launch -Xrun agents
3142   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3143   // back-end can launch with -Xdebug -Xrunjdwp.
3144   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3145     create_vm_init_libraries();
3146   }
3147 
3148   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3149   JvmtiExport::post_vm_initialized();
3150 
3151   Chunk::start_chunk_pool_cleaner_task();
3152 
3153   // initialize compiler(s)
3154   CompileBroker::compilation_init();
3155 
3156   Management::initialize(THREAD);
3157   if (HAS_PENDING_EXCEPTION) {
3158     // management agent fails to start possibly due to
3159     // configuration problem and is responsible for printing
3160     // stack trace if appropriate. Simply exit VM.
3161     vm_exit(1);
3162   }
3163 
3164   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3165   if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3166   if (MemProfiling)                   MemProfiler::engage();
3167   StatSampler::engage();
3168   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3169 
3170   BiasedLocking::init();
3171 
3172 
3173   // Start up the WatcherThread if there are any periodic tasks
3174   // NOTE:  All PeriodicTasks should be registered by now. If they
3175   //   aren't, late joiners might appear to start slowly (we might
3176   //   take a while to process their first tick).
3177   if (PeriodicTask::num_tasks() > 0) {
3178     WatcherThread::start();
3179   }
3180 
3181   create_vm_timer.end();
3182   return JNI_OK;
3183 }
3184 
3185 // type for the Agent_OnLoad and JVM_OnLoad entry points
3186 extern "C" {
3187   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3188 }
3189 // Find a command line agent library and return its entry point for
3190 //         -agentlib:  -agentpath:   -Xrun
3191 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3192 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3193   OnLoadEntry_t on_load_entry = NULL;
3194   void *library = agent->os_lib();  // check if we have looked it up before
3195 
3196   if (library == NULL) {
3197     char buffer[JVM_MAXPATHLEN];
3198     char ebuf[1024];
3199     const char *name = agent->name();
3200 
3201     if (agent->is_absolute_path()) {
3202       library = hpi::dll_load(name, ebuf, sizeof ebuf);
3203       if (library == NULL) {
3204         // If we can't find the agent, exit.
3205         vm_exit_during_initialization("Could not find agent library in absolute path", name);
3206       }
3207     } else {
3208       // Try to load the agent from the standard dll directory
3209       hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3210       library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3211 #ifdef KERNEL
3212       // Download instrument dll
3213       if (library == NULL && strcmp(name, "instrument") == 0) {
3214         char *props = Arguments::get_kernel_properties();
3215         char *home  = Arguments::get_java_home();
3216         const char *fmt   = "%s/bin/java %s -Dkernel.background.download=false"
3217                       " sun.jkernel.DownloadManager -download client_jvm";
3218         int length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3219         char *cmd = AllocateHeap(length);
3220         jio_snprintf(cmd, length, fmt, home, props);
3221         int status = os::fork_and_exec(cmd);
3222         FreeHeap(props);
3223         FreeHeap(cmd);
3224         if (status == -1) {
3225           warning(cmd);
3226           vm_exit_during_initialization("fork_and_exec failed: %s",
3227                                          strerror(errno));
3228         }
3229         // when this comes back the instrument.dll should be where it belongs.
3230         library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3231       }
3232 #endif // KERNEL
3233       if (library == NULL) { // Try the local directory
3234         char ns[1] = {0};
3235         hpi::dll_build_name(buffer, sizeof(buffer), ns, name);
3236         library = hpi::dll_load(buffer, ebuf, sizeof ebuf);
3237         if (library == NULL) {
3238           // If we can't find the agent, exit.
3239           vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name);
3240         }
3241       }
3242     }
3243     agent->set_os_lib(library);
3244   }
3245 
3246   // Find the OnLoad function.
3247   for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3248     on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index]));
3249     if (on_load_entry != NULL) break;
3250   }
3251   return on_load_entry;
3252 }
3253 
3254 // Find the JVM_OnLoad entry point
3255 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3256   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3257   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3258 }
3259 
3260 // Find the Agent_OnLoad entry point
3261 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3262   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3263   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3264 }
3265 
3266 // For backwards compatibility with -Xrun
3267 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3268 // treated like -agentpath:
3269 // Must be called before agent libraries are created
3270 void Threads::convert_vm_init_libraries_to_agents() {
3271   AgentLibrary* agent;
3272   AgentLibrary* next;
3273 
3274   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3275     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3276     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3277 
3278     // If there is an JVM_OnLoad function it will get called later,
3279     // otherwise see if there is an Agent_OnLoad
3280     if (on_load_entry == NULL) {
3281       on_load_entry = lookup_agent_on_load(agent);
3282       if (on_load_entry != NULL) {
3283         // switch it to the agent list -- so that Agent_OnLoad will be called,
3284         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3285         Arguments::convert_library_to_agent(agent);
3286       } else {
3287         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3288       }
3289     }
3290   }
3291 }
3292 
3293 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3294 // Invokes Agent_OnLoad
3295 // Called very early -- before JavaThreads exist
3296 void Threads::create_vm_init_agents() {
3297   extern struct JavaVM_ main_vm;
3298   AgentLibrary* agent;
3299 
3300   JvmtiExport::enter_onload_phase();
3301   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3302     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3303 
3304     if (on_load_entry != NULL) {
3305       // Invoke the Agent_OnLoad function
3306       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3307       if (err != JNI_OK) {
3308         vm_exit_during_initialization("agent library failed to init", agent->name());
3309       }
3310     } else {
3311       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3312     }
3313   }
3314   JvmtiExport::enter_primordial_phase();
3315 }
3316 
3317 extern "C" {
3318   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3319 }
3320 
3321 void Threads::shutdown_vm_agents() {
3322   // Send any Agent_OnUnload notifications
3323   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3324   extern struct JavaVM_ main_vm;
3325   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3326 
3327     // Find the Agent_OnUnload function.
3328     for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3329       Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3330                hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3331 
3332       // Invoke the Agent_OnUnload function
3333       if (unload_entry != NULL) {
3334         JavaThread* thread = JavaThread::current();
3335         ThreadToNativeFromVM ttn(thread);
3336         HandleMark hm(thread);
3337         (*unload_entry)(&main_vm);
3338         break;
3339       }
3340     }
3341   }
3342 }
3343 
3344 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3345 // Invokes JVM_OnLoad
3346 void Threads::create_vm_init_libraries() {
3347   extern struct JavaVM_ main_vm;
3348   AgentLibrary* agent;
3349 
3350   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3351     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3352 
3353     if (on_load_entry != NULL) {
3354       // Invoke the JVM_OnLoad function
3355       JavaThread* thread = JavaThread::current();
3356       ThreadToNativeFromVM ttn(thread);
3357       HandleMark hm(thread);
3358       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3359       if (err != JNI_OK) {
3360         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3361       }
3362     } else {
3363       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3364     }
3365   }
3366 }
3367 
3368 // Last thread running calls java.lang.Shutdown.shutdown()
3369 void JavaThread::invoke_shutdown_hooks() {
3370   HandleMark hm(this);
3371 
3372   // We could get here with a pending exception, if so clear it now.
3373   if (this->has_pending_exception()) {
3374     this->clear_pending_exception();
3375   }
3376 
3377   EXCEPTION_MARK;
3378   klassOop k =
3379     SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(),
3380                                       THREAD);
3381   if (k != NULL) {
3382     // SystemDictionary::resolve_or_null will return null if there was
3383     // an exception.  If we cannot load the Shutdown class, just don't
3384     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3385     // and finalizers (if runFinalizersOnExit is set) won't be run.
3386     // Note that if a shutdown hook was registered or runFinalizersOnExit
3387     // was called, the Shutdown class would have already been loaded
3388     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3389     instanceKlassHandle shutdown_klass (THREAD, k);
3390     JavaValue result(T_VOID);
3391     JavaCalls::call_static(&result,
3392                            shutdown_klass,
3393                            vmSymbolHandles::shutdown_method_name(),
3394                            vmSymbolHandles::void_method_signature(),
3395                            THREAD);
3396   }
3397   CLEAR_PENDING_EXCEPTION;
3398 }
3399 
3400 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3401 // the program falls off the end of main(). Another VM exit path is through
3402 // vm_exit() when the program calls System.exit() to return a value or when
3403 // there is a serious error in VM. The two shutdown paths are not exactly
3404 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3405 // and VM_Exit op at VM level.
3406 //
3407 // Shutdown sequence:
3408 //   + Wait until we are the last non-daemon thread to execute
3409 //     <-- every thing is still working at this moment -->
3410 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3411 //        shutdown hooks, run finalizers if finalization-on-exit
3412 //   + Call before_exit(), prepare for VM exit
3413 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3414 //        currently the only user of this mechanism is File.deleteOnExit())
3415 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3416 //        post thread end and vm death events to JVMTI,
3417 //        stop signal thread
3418 //   + Call JavaThread::exit(), it will:
3419 //      > release JNI handle blocks, remove stack guard pages
3420 //      > remove this thread from Threads list
3421 //     <-- no more Java code from this thread after this point -->
3422 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3423 //     the compiler threads at safepoint
3424 //     <-- do not use anything that could get blocked by Safepoint -->
3425 //   + Disable tracing at JNI/JVM barriers
3426 //   + Set _vm_exited flag for threads that are still running native code
3427 //   + Delete this thread
3428 //   + Call exit_globals()
3429 //      > deletes tty
3430 //      > deletes PerfMemory resources
3431 //   + Return to caller
3432 
3433 bool Threads::destroy_vm() {
3434   JavaThread* thread = JavaThread::current();
3435 
3436   // Wait until we are the last non-daemon thread to execute
3437   { MutexLocker nu(Threads_lock);
3438     while (Threads::number_of_non_daemon_threads() > 1 )
3439       // This wait should make safepoint checks, wait without a timeout,
3440       // and wait as a suspend-equivalent condition.
3441       //
3442       // Note: If the FlatProfiler is running and this thread is waiting
3443       // for another non-daemon thread to finish, then the FlatProfiler
3444       // is waiting for the external suspend request on this thread to
3445       // complete. wait_for_ext_suspend_completion() will eventually
3446       // timeout, but that takes time. Making this wait a suspend-
3447       // equivalent condition solves that timeout problem.
3448       //
3449       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3450                          Mutex::_as_suspend_equivalent_flag);
3451   }
3452 
3453   // Hang forever on exit if we are reporting an error.
3454   if (ShowMessageBoxOnError && is_error_reported()) {
3455     os::infinite_sleep();
3456   }
3457 
3458   if (JDK_Version::is_jdk12x_version()) {
3459     // We are the last thread running, so check if finalizers should be run.
3460     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3461     HandleMark rm(thread);
3462     Universe::run_finalizers_on_exit();
3463   } else {
3464     // run Java level shutdown hooks
3465     thread->invoke_shutdown_hooks();
3466   }
3467 
3468   before_exit(thread);
3469 
3470   thread->exit(true);
3471 
3472   // Stop VM thread.
3473   {
3474     // 4945125 The vm thread comes to a safepoint during exit.
3475     // GC vm_operations can get caught at the safepoint, and the
3476     // heap is unparseable if they are caught. Grab the Heap_lock
3477     // to prevent this. The GC vm_operations will not be able to
3478     // queue until after the vm thread is dead.
3479     MutexLocker ml(Heap_lock);
3480 
3481     VMThread::wait_for_vm_thread_exit();
3482     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3483     VMThread::destroy();
3484   }
3485 
3486   // clean up ideal graph printers
3487 #if defined(COMPILER2) && !defined(PRODUCT)
3488   IdealGraphPrinter::clean_up();
3489 #endif
3490 
3491   // Now, all Java threads are gone except daemon threads. Daemon threads
3492   // running Java code or in VM are stopped by the Safepoint. However,
3493   // daemon threads executing native code are still running.  But they
3494   // will be stopped at native=>Java/VM barriers. Note that we can't
3495   // simply kill or suspend them, as it is inherently deadlock-prone.
3496 
3497 #ifndef PRODUCT
3498   // disable function tracing at JNI/JVM barriers
3499   TraceHPI = false;
3500   TraceJNICalls = false;
3501   TraceJVMCalls = false;
3502   TraceRuntimeCalls = false;
3503 #endif
3504 
3505   VM_Exit::set_vm_exited();
3506 
3507   notify_vm_shutdown();
3508 
3509   delete thread;
3510 
3511   // exit_globals() will delete tty
3512   exit_globals();
3513 
3514   return true;
3515 }
3516 
3517 
3518 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3519   if (version == JNI_VERSION_1_1) return JNI_TRUE;
3520   return is_supported_jni_version(version);
3521 }
3522 
3523 
3524 jboolean Threads::is_supported_jni_version(jint version) {
3525   if (version == JNI_VERSION_1_2) return JNI_TRUE;
3526   if (version == JNI_VERSION_1_4) return JNI_TRUE;
3527   if (version == JNI_VERSION_1_6) return JNI_TRUE;
3528   return JNI_FALSE;
3529 }
3530 
3531 
3532 void Threads::add(JavaThread* p, bool force_daemon) {
3533   // The threads lock must be owned at this point
3534   assert_locked_or_safepoint(Threads_lock);
3535   p->set_next(_thread_list);
3536   _thread_list = p;
3537   _number_of_threads++;
3538   oop threadObj = p->threadObj();
3539   bool daemon = true;
3540   // Bootstrapping problem: threadObj can be null for initial
3541   // JavaThread (or for threads attached via JNI)
3542   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3543     _number_of_non_daemon_threads++;
3544     daemon = false;
3545   }
3546 
3547   ThreadService::add_thread(p, daemon);
3548 
3549   // Possible GC point.
3550   Events::log("Thread added: " INTPTR_FORMAT, p);
3551 }
3552 
3553 void Threads::remove(JavaThread* p) {
3554   // Extra scope needed for Thread_lock, so we can check
3555   // that we do not remove thread without safepoint code notice
3556   { MutexLocker ml(Threads_lock);
3557 
3558     assert(includes(p), "p must be present");
3559 
3560     JavaThread* current = _thread_list;
3561     JavaThread* prev    = NULL;
3562 
3563     while (current != p) {
3564       prev    = current;
3565       current = current->next();
3566     }
3567 
3568     if (prev) {
3569       prev->set_next(current->next());
3570     } else {
3571       _thread_list = p->next();
3572     }
3573     _number_of_threads--;
3574     oop threadObj = p->threadObj();
3575     bool daemon = true;
3576     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3577       _number_of_non_daemon_threads--;
3578       daemon = false;
3579 
3580       // Only one thread left, do a notify on the Threads_lock so a thread waiting
3581       // on destroy_vm will wake up.
3582       if (number_of_non_daemon_threads() == 1)
3583         Threads_lock->notify_all();
3584     }
3585     ThreadService::remove_thread(p, daemon);
3586 
3587     // Make sure that safepoint code disregard this thread. This is needed since
3588     // the thread might mess around with locks after this point. This can cause it
3589     // to do callbacks into the safepoint code. However, the safepoint code is not aware
3590     // of this thread since it is removed from the queue.
3591     p->set_terminated_value();
3592   } // unlock Threads_lock
3593 
3594   // Since Events::log uses a lock, we grab it outside the Threads_lock
3595   Events::log("Thread exited: " INTPTR_FORMAT, p);
3596 }
3597 
3598 // Threads_lock must be held when this is called (or must be called during a safepoint)
3599 bool Threads::includes(JavaThread* p) {
3600   assert(Threads_lock->is_locked(), "sanity check");
3601   ALL_JAVA_THREADS(q) {
3602     if (q == p ) {
3603       return true;
3604     }
3605   }
3606   return false;
3607 }
3608 
3609 // Operations on the Threads list for GC.  These are not explicitly locked,
3610 // but the garbage collector must provide a safe context for them to run.
3611 // In particular, these things should never be called when the Threads_lock
3612 // is held by some other thread. (Note: the Safepoint abstraction also
3613 // uses the Threads_lock to gurantee this property. It also makes sure that
3614 // all threads gets blocked when exiting or starting).
3615 
3616 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3617   ALL_JAVA_THREADS(p) {
3618     p->oops_do(f, cf);
3619   }
3620   VMThread::vm_thread()->oops_do(f, cf);
3621 }
3622 
3623 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3624   // Introduce a mechanism allowing parallel threads to claim threads as
3625   // root groups.  Overhead should be small enough to use all the time,
3626   // even in sequential code.
3627   SharedHeap* sh = SharedHeap::heap();
3628   bool is_par = (sh->n_par_threads() > 0);
3629   int cp = SharedHeap::heap()->strong_roots_parity();
3630   ALL_JAVA_THREADS(p) {
3631     if (p->claim_oops_do(is_par, cp)) {
3632       p->oops_do(f, cf);
3633     }
3634   }
3635   VMThread* vmt = VMThread::vm_thread();
3636   if (vmt->claim_oops_do(is_par, cp))
3637     vmt->oops_do(f, cf);
3638 }
3639 
3640 #ifndef SERIALGC
3641 // Used by ParallelScavenge
3642 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3643   ALL_JAVA_THREADS(p) {
3644     q->enqueue(new ThreadRootsTask(p));
3645   }
3646   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3647 }
3648 
3649 // Used by Parallel Old
3650 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3651   ALL_JAVA_THREADS(p) {
3652     q->enqueue(new ThreadRootsMarkingTask(p));
3653   }
3654   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3655 }
3656 #endif // SERIALGC
3657 
3658 void Threads::nmethods_do(CodeBlobClosure* cf) {
3659   ALL_JAVA_THREADS(p) {
3660     p->nmethods_do(cf);
3661   }
3662   VMThread::vm_thread()->nmethods_do(cf);
3663 }
3664 
3665 void Threads::gc_epilogue() {
3666   ALL_JAVA_THREADS(p) {
3667     p->gc_epilogue();
3668   }
3669 }
3670 
3671 void Threads::gc_prologue() {
3672   ALL_JAVA_THREADS(p) {
3673     p->gc_prologue();
3674   }
3675 }
3676 
3677 void Threads::deoptimized_wrt_marked_nmethods() {
3678   ALL_JAVA_THREADS(p) {
3679     p->deoptimized_wrt_marked_nmethods();
3680   }
3681 }
3682 
3683 
3684 // Get count Java threads that are waiting to enter the specified monitor.
3685 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3686   address monitor, bool doLock) {
3687   assert(doLock || SafepointSynchronize::is_at_safepoint(),
3688     "must grab Threads_lock or be at safepoint");
3689   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3690 
3691   int i = 0;
3692   {
3693     MutexLockerEx ml(doLock ? Threads_lock : NULL);
3694     ALL_JAVA_THREADS(p) {
3695       if (p->is_Compiler_thread()) continue;
3696 
3697       address pending = (address)p->current_pending_monitor();
3698       if (pending == monitor) {             // found a match
3699         if (i < count) result->append(p);   // save the first count matches
3700         i++;
3701       }
3702     }
3703   }
3704   return result;
3705 }
3706 
3707 
3708 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3709   assert(doLock ||
3710          Threads_lock->owned_by_self() ||
3711          SafepointSynchronize::is_at_safepoint(),
3712          "must grab Threads_lock or be at safepoint");
3713 
3714   // NULL owner means not locked so we can skip the search
3715   if (owner == NULL) return NULL;
3716 
3717   {
3718     MutexLockerEx ml(doLock ? Threads_lock : NULL);
3719     ALL_JAVA_THREADS(p) {
3720       // first, see if owner is the address of a Java thread
3721       if (owner == (address)p) return p;
3722     }
3723   }
3724   assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3725   if (UseHeavyMonitors) return NULL;
3726 
3727   //
3728   // If we didn't find a matching Java thread and we didn't force use of
3729   // heavyweight monitors, then the owner is the stack address of the
3730   // Lock Word in the owning Java thread's stack.
3731   //
3732   JavaThread* the_owner = NULL;
3733   {
3734     MutexLockerEx ml(doLock ? Threads_lock : NULL);
3735     ALL_JAVA_THREADS(q) {
3736       if (q->is_lock_owned(owner)) {
3737         the_owner = q;
3738         break;
3739       }
3740     }
3741   }
3742   assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3743   return the_owner;
3744 }
3745 
3746 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3747 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3748   char buf[32];
3749   st->print_cr(os::local_time_string(buf, sizeof(buf)));
3750 
3751   st->print_cr("Full thread dump %s (%s %s):",
3752                 Abstract_VM_Version::vm_name(),
3753                 Abstract_VM_Version::vm_release(),
3754                 Abstract_VM_Version::vm_info_string()
3755                );
3756   st->cr();
3757 
3758 #ifndef SERIALGC
3759   // Dump concurrent locks
3760   ConcurrentLocksDump concurrent_locks;
3761   if (print_concurrent_locks) {
3762     concurrent_locks.dump_at_safepoint();
3763   }
3764 #endif // SERIALGC
3765 
3766   ALL_JAVA_THREADS(p) {
3767     ResourceMark rm;
3768     p->print_on(st);
3769     if (print_stacks) {
3770       if (internal_format) {
3771         p->trace_stack();
3772       } else {
3773         p->print_stack_on(st);
3774       }
3775     }
3776     st->cr();
3777 #ifndef SERIALGC
3778     if (print_concurrent_locks) {
3779       concurrent_locks.print_locks_on(p, st);
3780     }
3781 #endif // SERIALGC
3782   }
3783 
3784   VMThread::vm_thread()->print_on(st);
3785   st->cr();
3786   Universe::heap()->print_gc_threads_on(st);
3787   WatcherThread* wt = WatcherThread::watcher_thread();
3788   if (wt != NULL) wt->print_on(st);
3789   st->cr();
3790   CompileBroker::print_compiler_threads_on(st);
3791   st->flush();
3792 }
3793 
3794 // Threads::print_on_error() is called by fatal error handler. It's possible
3795 // that VM is not at safepoint and/or current thread is inside signal handler.
3796 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3797 // memory (even in resource area), it might deadlock the error handler.
3798 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3799   bool found_current = false;
3800   st->print_cr("Java Threads: ( => current thread )");
3801   ALL_JAVA_THREADS(thread) {
3802     bool is_current = (current == thread);
3803     found_current = found_current || is_current;
3804 
3805     st->print("%s", is_current ? "=>" : "  ");
3806 
3807     st->print(PTR_FORMAT, thread);
3808     st->print(" ");
3809     thread->print_on_error(st, buf, buflen);
3810     st->cr();
3811   }
3812   st->cr();
3813 
3814   st->print_cr("Other Threads:");
3815   if (VMThread::vm_thread()) {
3816     bool is_current = (current == VMThread::vm_thread());
3817     found_current = found_current || is_current;
3818     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
3819 
3820     st->print(PTR_FORMAT, VMThread::vm_thread());
3821     st->print(" ");
3822     VMThread::vm_thread()->print_on_error(st, buf, buflen);
3823     st->cr();
3824   }
3825   WatcherThread* wt = WatcherThread::watcher_thread();
3826   if (wt != NULL) {
3827     bool is_current = (current == wt);
3828     found_current = found_current || is_current;
3829     st->print("%s", is_current ? "=>" : "  ");
3830 
3831     st->print(PTR_FORMAT, wt);
3832     st->print(" ");
3833     wt->print_on_error(st, buf, buflen);
3834     st->cr();
3835   }
3836   if (!found_current) {
3837     st->cr();
3838     st->print("=>" PTR_FORMAT " (exited) ", current);
3839     current->print_on_error(st, buf, buflen);
3840     st->cr();
3841   }
3842 }
3843 
3844 
3845 // Lifecycle management for TSM ParkEvents.
3846 // ParkEvents are type-stable (TSM).
3847 // In our particular implementation they happen to be immortal.
3848 //
3849 // We manage concurrency on the FreeList with a CAS-based
3850 // detach-modify-reattach idiom that avoids the ABA problems
3851 // that would otherwise be present in a simple CAS-based
3852 // push-pop implementation.   (push-one and pop-all)
3853 //
3854 // Caveat: Allocate() and Release() may be called from threads
3855 // other than the thread associated with the Event!
3856 // If we need to call Allocate() when running as the thread in
3857 // question then look for the PD calls to initialize native TLS.
3858 // Native TLS (Win32/Linux/Solaris) can only be initialized or
3859 // accessed by the associated thread.
3860 // See also pd_initialize().
3861 //
3862 // Note that we could defer associating a ParkEvent with a thread
3863 // until the 1st time the thread calls park().  unpark() calls to
3864 // an unprovisioned thread would be ignored.  The first park() call
3865 // for a thread would allocate and associate a ParkEvent and return
3866 // immediately.
3867 
3868 volatile int ParkEvent::ListLock = 0 ;
3869 ParkEvent * volatile ParkEvent::FreeList = NULL ;
3870 
3871 ParkEvent * ParkEvent::Allocate (Thread * t) {
3872   // In rare cases -- JVM_RawMonitor* operations -- we can find t == null.
3873   ParkEvent * ev ;
3874 
3875   // Start by trying to recycle an existing but unassociated
3876   // ParkEvent from the global free list.
3877   for (;;) {
3878     ev = FreeList ;
3879     if (ev == NULL) break ;
3880     // 1: Detach - sequester or privatize the list
3881     // Tantamount to ev = Swap (&FreeList, NULL)
3882     if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) {
3883        continue ;
3884     }
3885 
3886     // We've detached the list.  The list in-hand is now
3887     // local to this thread.   This thread can operate on the
3888     // list without risk of interference from other threads.
3889     // 2: Extract -- pop the 1st element from the list.
3890     ParkEvent * List = ev->FreeNext ;
3891     if (List == NULL) break ;
3892     for (;;) {
3893         // 3: Try to reattach the residual list
3894         guarantee (List != NULL, "invariant") ;
3895         ParkEvent * Arv =  (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
3896         if (Arv == NULL) break ;
3897 
3898         // New nodes arrived.  Try to detach the recent arrivals.
3899         if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
3900             continue ;
3901         }
3902         guarantee (Arv != NULL, "invariant") ;
3903         // 4: Merge Arv into List
3904         ParkEvent * Tail = List ;
3905         while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
3906         Tail->FreeNext = Arv ;
3907     }
3908     break ;
3909   }
3910 
3911   if (ev != NULL) {
3912     guarantee (ev->AssociatedWith == NULL, "invariant") ;
3913   } else {
3914     // Do this the hard way -- materialize a new ParkEvent.
3915     // In rare cases an allocating thread might detach a long list --
3916     // installing null into FreeList -- and then stall or be obstructed.
3917     // A 2nd thread calling Allocate() would see FreeList == null.
3918     // The list held privately by the 1st thread is unavailable to the 2nd thread.
3919     // In that case the 2nd thread would have to materialize a new ParkEvent,
3920     // even though free ParkEvents existed in the system.  In this case we end up
3921     // with more ParkEvents in circulation than we need, but the race is
3922     // rare and the outcome is benign.  Ideally, the # of extant ParkEvents
3923     // is equal to the maximum # of threads that existed at any one time.
3924     // Because of the race mentioned above, segments of the freelist
3925     // can be transiently inaccessible.  At worst we may end up with the
3926     // # of ParkEvents in circulation slightly above the ideal.
3927     // Note that if we didn't have the TSM/immortal constraint, then
3928     // when reattaching, above, we could trim the list.
3929     ev = new ParkEvent () ;
3930     guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ;
3931   }
3932   ev->reset() ;                     // courtesy to caller
3933   ev->AssociatedWith = t ;          // Associate ev with t
3934   ev->FreeNext       = NULL ;
3935   return ev ;
3936 }
3937 
3938 void ParkEvent::Release (ParkEvent * ev) {
3939   if (ev == NULL) return ;
3940   guarantee (ev->FreeNext == NULL      , "invariant") ;
3941   ev->AssociatedWith = NULL ;
3942   for (;;) {
3943     // Push ev onto FreeList
3944     // The mechanism is "half" lock-free.
3945     ParkEvent * List = FreeList ;
3946     ev->FreeNext = List ;
3947     if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ;
3948   }
3949 }
3950 
3951 // Override operator new and delete so we can ensure that the
3952 // least significant byte of ParkEvent addresses is 0.
3953 // Beware that excessive address alignment is undesirable
3954 // as it can result in D$ index usage imbalance as
3955 // well as bank access imbalance on Niagara-like platforms,
3956 // although Niagara's hash function should help.
3957 
3958 void * ParkEvent::operator new (size_t sz) {
3959   return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ;
3960 }
3961 
3962 void ParkEvent::operator delete (void * a) {
3963   // ParkEvents are type-stable and immortal ...
3964   ShouldNotReachHere();
3965 }
3966 
3967 
3968 // 6399321 As a temporary measure we copied & modified the ParkEvent::
3969 // allocate() and release() code for use by Parkers.  The Parker:: forms
3970 // will eventually be removed as we consolide and shift over to ParkEvents
3971 // for both builtin synchronization and JSR166 operations.
3972 
3973 volatile int Parker::ListLock = 0 ;
3974 Parker * volatile Parker::FreeList = NULL ;
3975 
3976 Parker * Parker::Allocate (JavaThread * t) {
3977   guarantee (t != NULL, "invariant") ;
3978   Parker * p ;
3979 
3980   // Start by trying to recycle an existing but unassociated
3981   // Parker from the global free list.
3982   for (;;) {
3983     p = FreeList ;
3984     if (p  == NULL) break ;
3985     // 1: Detach
3986     // Tantamount to p = Swap (&FreeList, NULL)
3987     if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) {
3988        continue ;
3989     }
3990 
3991     // We've detached the list.  The list in-hand is now
3992     // local to this thread.   This thread can operate on the
3993     // list without risk of interference from other threads.
3994     // 2: Extract -- pop the 1st element from the list.
3995     Parker * List = p->FreeNext ;
3996     if (List == NULL) break ;
3997     for (;;) {
3998         // 3: Try to reattach the residual list
3999         guarantee (List != NULL, "invariant") ;
4000         Parker * Arv =  (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ;
4001         if (Arv == NULL) break ;
4002 
4003         // New nodes arrived.  Try to detach the recent arrivals.
4004         if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) {
4005             continue ;
4006         }
4007         guarantee (Arv != NULL, "invariant") ;
4008         // 4: Merge Arv into List
4009         Parker * Tail = List ;
4010         while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ;
4011         Tail->FreeNext = Arv ;
4012     }
4013     break ;
4014   }
4015 
4016   if (p != NULL) {
4017     guarantee (p->AssociatedWith == NULL, "invariant") ;
4018   } else {
4019     // Do this the hard way -- materialize a new Parker..
4020     // In rare cases an allocating thread might detach
4021     // a long list -- installing null into FreeList --and
4022     // then stall.  Another thread calling Allocate() would see
4023     // FreeList == null and then invoke the ctor.  In this case we
4024     // end up with more Parkers in circulation than we need, but
4025     // the race is rare and the outcome is benign.
4026     // Ideally, the # of extant Parkers is equal to the
4027     // maximum # of threads that existed at any one time.
4028     // Because of the race mentioned above, segments of the
4029     // freelist can be transiently inaccessible.  At worst
4030     // we may end up with the # of Parkers in circulation
4031     // slightly above the ideal.
4032     p = new Parker() ;
4033   }
4034   p->AssociatedWith = t ;          // Associate p with t
4035   p->FreeNext       = NULL ;
4036   return p ;
4037 }
4038 
4039 
4040 void Parker::Release (Parker * p) {
4041   if (p == NULL) return ;
4042   guarantee (p->AssociatedWith != NULL, "invariant") ;
4043   guarantee (p->FreeNext == NULL      , "invariant") ;
4044   p->AssociatedWith = NULL ;
4045   for (;;) {
4046     // Push p onto FreeList
4047     Parker * List = FreeList ;
4048     p->FreeNext = List ;
4049     if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ;
4050   }
4051 }
4052 
4053 void Threads::verify() {
4054   ALL_JAVA_THREADS(p) {
4055     p->verify();
4056   }
4057   VMThread* thread = VMThread::vm_thread();
4058   if (thread != NULL) thread->verify();
4059 }