1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "interpreter/interpreter.hpp"
  33 #include "interpreter/linkResolver.hpp"
  34 #include "interpreter/oopMapCache.hpp"
  35 #include "jvmtifiles/jvmtiEnv.hpp"
  36 #include "memory/gcLocker.inline.hpp"
  37 #include "memory/metaspaceShared.hpp"
  38 #include "memory/oopFactory.hpp"
  39 #include "memory/universe.inline.hpp"
  40 #include "oops/instanceKlass.hpp"
  41 #include "oops/objArrayOop.hpp"
  42 #include "oops/oop.inline.hpp"
  43 #include "oops/symbol.hpp"
  44 #include "prims/jvm_misc.hpp"
  45 #include "prims/jvmtiExport.hpp"
  46 #include "prims/jvmtiThreadState.hpp"
  47 #include "prims/privilegedStack.hpp"
  48 #include "runtime/aprofiler.hpp"
  49 #include "runtime/arguments.hpp"
  50 #include "runtime/biasedLocking.hpp"
  51 #include "runtime/deoptimization.hpp"
  52 #include "runtime/fprofiler.hpp"
  53 #include "runtime/frame.inline.hpp"
  54 #include "runtime/init.hpp"
  55 #include "runtime/interfaceSupport.hpp"
  56 #include "runtime/java.hpp"
  57 #include "runtime/javaCalls.hpp"
  58 #include "runtime/jniPeriodicChecker.hpp"
  59 #include "runtime/memprofiler.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/objectMonitor.hpp"
  62 #include "runtime/osThread.hpp"
  63 #include "runtime/safepoint.hpp"
  64 #include "runtime/sharedRuntime.hpp"
  65 #include "runtime/statSampler.hpp"
  66 #include "runtime/stubRoutines.hpp"
  67 #include "runtime/task.hpp"
  68 #include "runtime/thread.inline.hpp"
  69 #include "runtime/threadCritical.hpp"
  70 #include "runtime/threadLocalStorage.hpp"
  71 #include "runtime/vframe.hpp"
  72 #include "runtime/vframeArray.hpp"
  73 #include "runtime/vframe_hp.hpp"
  74 #include "runtime/vmThread.hpp"
  75 #include "runtime/vm_operations.hpp"
  76 #include "services/attachListener.hpp"
  77 #include "services/management.hpp"
  78 #include "services/memTracker.hpp"
  79 #include "services/threadService.hpp"
  80 #include "trace/traceEventTypes.hpp"
  81 #include "utilities/defaultStream.hpp"
  82 #include "utilities/dtrace.hpp"
  83 #include "utilities/events.hpp"
  84 #include "utilities/preserveException.hpp"
  85 #include "utilities/macros.hpp"
  86 #ifdef TARGET_OS_FAMILY_linux
  87 # include "os_linux.inline.hpp"
  88 #endif
  89 #ifdef TARGET_OS_FAMILY_solaris
  90 # include "os_solaris.inline.hpp"
  91 #endif
  92 #ifdef TARGET_OS_FAMILY_windows
  93 # include "os_windows.inline.hpp"
  94 #endif
  95 #ifdef TARGET_OS_FAMILY_bsd
  96 # include "os_bsd.inline.hpp"
  97 #endif
  98 #if INCLUDE_ALL_GCS
  99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
 102 #endif // INCLUDE_ALL_GCS
 103 #ifdef COMPILER1
 104 #include "c1/c1_Compiler.hpp"
 105 #endif
 106 #ifdef COMPILER2
 107 #include "opto/c2compiler.hpp"
 108 #include "opto/idealGraphPrinter.hpp"
 109 #endif
 110 
 111 #ifdef DTRACE_ENABLED
 112 
 113 // Only bother with this argument setup if dtrace is available
 114 
 115 #ifndef USDT2
 116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
 118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
 119   intptr_t, intptr_t, bool);
 120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
 121   intptr_t, intptr_t, bool);
 122 
 123 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 124   {                                                                        \
 125     ResourceMark rm(this);                                                 \
 126     int len = 0;                                                           \
 127     const char* name = (javathread)->get_thread_name();                    \
 128     len = strlen(name);                                                    \
 129     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
 130       name, len,                                                           \
 131       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 132       (javathread)->osthread()->thread_id(),                               \
 133       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 134   }
 135 
 136 #else /* USDT2 */
 137 
 138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
 139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
 140 
 141 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 142   {                                                                        \
 143     ResourceMark rm(this);                                                 \
 144     int len = 0;                                                           \
 145     const char* name = (javathread)->get_thread_name();                    \
 146     len = strlen(name);                                                    \
 147     HOTSPOT_THREAD_PROBE_##probe(  /* probe = start, stop */               \
 148       (char *) name, len,                                                           \
 149       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 150       (uintptr_t) (javathread)->osthread()->thread_id(),                               \
 151       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 152   }
 153 
 154 #endif /* USDT2 */
 155 
 156 #else //  ndef DTRACE_ENABLED
 157 
 158 #define DTRACE_THREAD_PROBE(probe, javathread)
 159 
 160 #endif // ndef DTRACE_ENABLED
 161 
 162 
 163 // Class hierarchy
 164 // - Thread
 165 //   - VMThread
 166 //   - WatcherThread
 167 //   - ConcurrentMarkSweepThread
 168 //   - JavaThread
 169 //     - CompilerThread
 170 
 171 // ======= Thread ========
 172 // Support for forcing alignment of thread objects for biased locking
 173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 174   if (UseBiasedLocking) {
 175     const int alignment = markOopDesc::biased_lock_alignment;
 176     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 177     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 178                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 179                                               AllocFailStrategy::RETURN_NULL);
 180     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
 181     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 182            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 183            "JavaThread alignment code overflowed allocated storage");
 184     if (TraceBiasedLocking) {
 185       if (aligned_addr != real_malloc_addr)
 186         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 187                       real_malloc_addr, aligned_addr);
 188     }
 189     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 190     return aligned_addr;
 191   } else {
 192     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 193                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 194   }
 195 }
 196 
 197 void Thread::operator delete(void* p) {
 198   if (UseBiasedLocking) {
 199     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
 200     FreeHeap(real_malloc_addr, mtThread);
 201   } else {
 202     FreeHeap(p, mtThread);
 203   }
 204 }
 205 
 206 
 207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 208 // JavaThread
 209 
 210 
 211 Thread::Thread() {
 212   // stack and get_thread
 213   set_stack_base(NULL);
 214   set_stack_size(0);
 215   set_self_raw_id(0);
 216   set_lgrp_id(-1);
 217 
 218   // allocated data structures
 219   set_osthread(NULL);
 220   set_resource_area(new (mtThread)ResourceArea());
 221   set_handle_area(new (mtThread) HandleArea(NULL));
 222   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true));
 223   set_active_handles(NULL);
 224   set_free_handle_block(NULL);
 225   set_last_handle_mark(NULL);
 226 
 227   // This initial value ==> never claimed.
 228   _oops_do_parity = 0;
 229 
 230   // the handle mark links itself to last_handle_mark
 231   new HandleMark(this);
 232 
 233   // plain initialization
 234   debug_only(_owned_locks = NULL;)
 235   debug_only(_allow_allocation_count = 0;)
 236   NOT_PRODUCT(_allow_safepoint_count = 0;)
 237   NOT_PRODUCT(_skip_gcalot = false;)
 238   CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
 239   _jvmti_env_iteration_count = 0;
 240   set_allocated_bytes(0);
 241   set_trace_buffer(NULL);
 242   _vm_operation_started_count = 0;
 243   _vm_operation_completed_count = 0;
 244   _current_pending_monitor = NULL;
 245   _current_pending_monitor_is_from_java = true;
 246   _current_waiting_monitor = NULL;
 247   _num_nested_signal = 0;
 248   omFreeList = NULL ;
 249   omFreeCount = 0 ;
 250   omFreeProvision = 32 ;
 251   omInUseList = NULL ;
 252   omInUseCount = 0 ;
 253 
 254 #ifdef ASSERT
 255   _visited_for_critical_count = false;
 256 #endif
 257 
 258   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
 259   _suspend_flags = 0;
 260 
 261   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 262   _hashStateX = os::random() ;
 263   _hashStateY = 842502087 ;
 264   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
 265   _hashStateW = 273326509 ;
 266 
 267   _OnTrap   = 0 ;
 268   _schedctl = NULL ;
 269   _Stalled  = 0 ;
 270   _TypeTag  = 0x2BAD ;
 271 
 272   // Many of the following fields are effectively final - immutable
 273   // Note that nascent threads can't use the Native Monitor-Mutex
 274   // construct until the _MutexEvent is initialized ...
 275   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 276   // we might instead use a stack of ParkEvents that we could provision on-demand.
 277   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 278   // and ::Release()
 279   _ParkEvent   = ParkEvent::Allocate (this) ;
 280   _SleepEvent  = ParkEvent::Allocate (this) ;
 281   _MutexEvent  = ParkEvent::Allocate (this) ;
 282   _MuxEvent    = ParkEvent::Allocate (this) ;
 283 
 284 #ifdef CHECK_UNHANDLED_OOPS
 285   if (CheckUnhandledOops) {
 286     _unhandled_oops = new UnhandledOops(this);
 287   }
 288 #endif // CHECK_UNHANDLED_OOPS
 289 #ifdef ASSERT
 290   if (UseBiasedLocking) {
 291     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 292     assert(this == _real_malloc_address ||
 293            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 294            "bug in forced alignment of thread objects");
 295   }
 296 #endif /* ASSERT */
 297 }
 298 
 299 void Thread::initialize_thread_local_storage() {
 300   // Note: Make sure this method only calls
 301   // non-blocking operations. Otherwise, it might not work
 302   // with the thread-startup/safepoint interaction.
 303 
 304   // During Java thread startup, safepoint code should allow this
 305   // method to complete because it may need to allocate memory to
 306   // store information for the new thread.
 307 
 308   // initialize structure dependent on thread local storage
 309   ThreadLocalStorage::set_thread(this);
 310 }
 311 
 312 void Thread::record_stack_base_and_size() {
 313   set_stack_base(os::current_stack_base());
 314   set_stack_size(os::current_stack_size());
 315   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 316   // in initialize_thread(). Without the adjustment, stack size is
 317   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 318   // So far, only Solaris has real implementation of initialize_thread().
 319   //
 320   // set up any platform-specific state.
 321   os::initialize_thread(this);
 322 
 323 #if INCLUDE_NMT
 324   // record thread's native stack, stack grows downward
 325   address stack_low_addr = stack_base() - stack_size();
 326   MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
 327       CURRENT_PC);
 328 #endif // INCLUDE_NMT
 329 }
 330 
 331 
 332 Thread::~Thread() {
 333   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 334   ObjectSynchronizer::omFlush (this) ;
 335 
 336   // stack_base can be NULL if the thread is never started or exited before
 337   // record_stack_base_and_size called. Although, we would like to ensure
 338   // that all started threads do call record_stack_base_and_size(), there is
 339   // not proper way to enforce that.
 340 #if INCLUDE_NMT
 341   if (_stack_base != NULL) {
 342     address low_stack_addr = stack_base() - stack_size();
 343     MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
 344 #ifdef ASSERT
 345     set_stack_base(NULL);
 346 #endif
 347   }
 348 #endif // INCLUDE_NMT
 349 
 350   // deallocate data structures
 351   delete resource_area();
 352   // since the handle marks are using the handle area, we have to deallocated the root
 353   // handle mark before deallocating the thread's handle area,
 354   assert(last_handle_mark() != NULL, "check we have an element");
 355   delete last_handle_mark();
 356   assert(last_handle_mark() == NULL, "check we have reached the end");
 357 
 358   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 359   // We NULL out the fields for good hygiene.
 360   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 361   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 362   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 363   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 364 
 365   delete handle_area();
 366   delete metadata_handles();
 367 
 368   // osthread() can be NULL, if creation of thread failed.
 369   if (osthread() != NULL) os::free_thread(osthread());
 370 
 371   delete _SR_lock;
 372 
 373   // clear thread local storage if the Thread is deleting itself
 374   if (this == Thread::current()) {
 375     ThreadLocalStorage::set_thread(NULL);
 376   } else {
 377     // In the case where we're not the current thread, invalidate all the
 378     // caches in case some code tries to get the current thread or the
 379     // thread that was destroyed, and gets stale information.
 380     ThreadLocalStorage::invalidate_all();
 381   }
 382   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 383 }
 384 
 385 // NOTE: dummy function for assertion purpose.
 386 void Thread::run() {
 387   ShouldNotReachHere();
 388 }
 389 
 390 #ifdef ASSERT
 391 // Private method to check for dangling thread pointer
 392 void check_for_dangling_thread_pointer(Thread *thread) {
 393  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 394          "possibility of dangling Thread pointer");
 395 }
 396 #endif
 397 
 398 
 399 #ifndef PRODUCT
 400 // Tracing method for basic thread operations
 401 void Thread::trace(const char* msg, const Thread* const thread) {
 402   if (!TraceThreadEvents) return;
 403   ResourceMark rm;
 404   ThreadCritical tc;
 405   const char *name = "non-Java thread";
 406   int prio = -1;
 407   if (thread->is_Java_thread()
 408       && !thread->is_Compiler_thread()) {
 409     // The Threads_lock must be held to get information about
 410     // this thread but may not be in some situations when
 411     // tracing  thread events.
 412     bool release_Threads_lock = false;
 413     if (!Threads_lock->owned_by_self()) {
 414       Threads_lock->lock();
 415       release_Threads_lock = true;
 416     }
 417     JavaThread* jt = (JavaThread *)thread;
 418     name = (char *)jt->get_thread_name();
 419     oop thread_oop = jt->threadObj();
 420     if (thread_oop != NULL) {
 421       prio = java_lang_Thread::priority(thread_oop);
 422     }
 423     if (release_Threads_lock) {
 424       Threads_lock->unlock();
 425     }
 426   }
 427   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 428 }
 429 #endif
 430 
 431 
 432 ThreadPriority Thread::get_priority(const Thread* const thread) {
 433   trace("get priority", thread);
 434   ThreadPriority priority;
 435   // Can return an error!
 436   (void)os::get_priority(thread, priority);
 437   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 438   return priority;
 439 }
 440 
 441 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 442   trace("set priority", thread);
 443   debug_only(check_for_dangling_thread_pointer(thread);)
 444   // Can return an error!
 445   (void)os::set_priority(thread, priority);
 446 }
 447 
 448 
 449 void Thread::start(Thread* thread) {
 450   trace("start", thread);
 451   // Start is different from resume in that its safety is guaranteed by context or
 452   // being called from a Java method synchronized on the Thread object.
 453   if (!DisableStartThread) {
 454     if (thread->is_Java_thread()) {
 455       // Initialize the thread state to RUNNABLE before starting this thread.
 456       // Can not set it after the thread started because we do not know the
 457       // exact thread state at that time. It could be in MONITOR_WAIT or
 458       // in SLEEPING or some other state.
 459       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 460                                           java_lang_Thread::RUNNABLE);
 461     }
 462     os::start_thread(thread);
 463   }
 464 }
 465 
 466 // Enqueue a VM_Operation to do the job for us - sometime later
 467 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 468   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 469   VMThread::execute(vm_stop);
 470 }
 471 
 472 
 473 //
 474 // Check if an external suspend request has completed (or has been
 475 // cancelled). Returns true if the thread is externally suspended and
 476 // false otherwise.
 477 //
 478 // The bits parameter returns information about the code path through
 479 // the routine. Useful for debugging:
 480 //
 481 // set in is_ext_suspend_completed():
 482 // 0x00000001 - routine was entered
 483 // 0x00000010 - routine return false at end
 484 // 0x00000100 - thread exited (return false)
 485 // 0x00000200 - suspend request cancelled (return false)
 486 // 0x00000400 - thread suspended (return true)
 487 // 0x00001000 - thread is in a suspend equivalent state (return true)
 488 // 0x00002000 - thread is native and walkable (return true)
 489 // 0x00004000 - thread is native_trans and walkable (needed retry)
 490 //
 491 // set in wait_for_ext_suspend_completion():
 492 // 0x00010000 - routine was entered
 493 // 0x00020000 - suspend request cancelled before loop (return false)
 494 // 0x00040000 - thread suspended before loop (return true)
 495 // 0x00080000 - suspend request cancelled in loop (return false)
 496 // 0x00100000 - thread suspended in loop (return true)
 497 // 0x00200000 - suspend not completed during retry loop (return false)
 498 //
 499 
 500 // Helper class for tracing suspend wait debug bits.
 501 //
 502 // 0x00000100 indicates that the target thread exited before it could
 503 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 504 // 0x00080000 each indicate a cancelled suspend request so they don't
 505 // count as wait failures either.
 506 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 507 
 508 class TraceSuspendDebugBits : public StackObj {
 509  private:
 510   JavaThread * jt;
 511   bool         is_wait;
 512   bool         called_by_wait;  // meaningful when !is_wait
 513   uint32_t *   bits;
 514 
 515  public:
 516   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 517                         uint32_t *_bits) {
 518     jt             = _jt;
 519     is_wait        = _is_wait;
 520     called_by_wait = _called_by_wait;
 521     bits           = _bits;
 522   }
 523 
 524   ~TraceSuspendDebugBits() {
 525     if (!is_wait) {
 526 #if 1
 527       // By default, don't trace bits for is_ext_suspend_completed() calls.
 528       // That trace is very chatty.
 529       return;
 530 #else
 531       if (!called_by_wait) {
 532         // If tracing for is_ext_suspend_completed() is enabled, then only
 533         // trace calls to it from wait_for_ext_suspend_completion()
 534         return;
 535       }
 536 #endif
 537     }
 538 
 539     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 540       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 541         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 542         ResourceMark rm;
 543 
 544         tty->print_cr(
 545             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 546             jt->get_thread_name(), *bits);
 547 
 548         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 549       }
 550     }
 551   }
 552 };
 553 #undef DEBUG_FALSE_BITS
 554 
 555 
 556 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 557   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 558 
 559   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 560   bool do_trans_retry;           // flag to force the retry
 561 
 562   *bits |= 0x00000001;
 563 
 564   do {
 565     do_trans_retry = false;
 566 
 567     if (is_exiting()) {
 568       // Thread is in the process of exiting. This is always checked
 569       // first to reduce the risk of dereferencing a freed JavaThread.
 570       *bits |= 0x00000100;
 571       return false;
 572     }
 573 
 574     if (!is_external_suspend()) {
 575       // Suspend request is cancelled. This is always checked before
 576       // is_ext_suspended() to reduce the risk of a rogue resume
 577       // confusing the thread that made the suspend request.
 578       *bits |= 0x00000200;
 579       return false;
 580     }
 581 
 582     if (is_ext_suspended()) {
 583       // thread is suspended
 584       *bits |= 0x00000400;
 585       return true;
 586     }
 587 
 588     // Now that we no longer do hard suspends of threads running
 589     // native code, the target thread can be changing thread state
 590     // while we are in this routine:
 591     //
 592     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 593     //
 594     // We save a copy of the thread state as observed at this moment
 595     // and make our decision about suspend completeness based on the
 596     // copy. This closes the race where the thread state is seen as
 597     // _thread_in_native_trans in the if-thread_blocked check, but is
 598     // seen as _thread_blocked in if-thread_in_native_trans check.
 599     JavaThreadState save_state = thread_state();
 600 
 601     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 602       // If the thread's state is _thread_blocked and this blocking
 603       // condition is known to be equivalent to a suspend, then we can
 604       // consider the thread to be externally suspended. This means that
 605       // the code that sets _thread_blocked has been modified to do
 606       // self-suspension if the blocking condition releases. We also
 607       // used to check for CONDVAR_WAIT here, but that is now covered by
 608       // the _thread_blocked with self-suspension check.
 609       //
 610       // Return true since we wouldn't be here unless there was still an
 611       // external suspend request.
 612       *bits |= 0x00001000;
 613       return true;
 614     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 615       // Threads running native code will self-suspend on native==>VM/Java
 616       // transitions. If its stack is walkable (should always be the case
 617       // unless this function is called before the actual java_suspend()
 618       // call), then the wait is done.
 619       *bits |= 0x00002000;
 620       return true;
 621     } else if (!called_by_wait && !did_trans_retry &&
 622                save_state == _thread_in_native_trans &&
 623                frame_anchor()->walkable()) {
 624       // The thread is transitioning from thread_in_native to another
 625       // thread state. check_safepoint_and_suspend_for_native_trans()
 626       // will force the thread to self-suspend. If it hasn't gotten
 627       // there yet we may have caught the thread in-between the native
 628       // code check above and the self-suspend. Lucky us. If we were
 629       // called by wait_for_ext_suspend_completion(), then it
 630       // will be doing the retries so we don't have to.
 631       //
 632       // Since we use the saved thread state in the if-statement above,
 633       // there is a chance that the thread has already transitioned to
 634       // _thread_blocked by the time we get here. In that case, we will
 635       // make a single unnecessary pass through the logic below. This
 636       // doesn't hurt anything since we still do the trans retry.
 637 
 638       *bits |= 0x00004000;
 639 
 640       // Once the thread leaves thread_in_native_trans for another
 641       // thread state, we break out of this retry loop. We shouldn't
 642       // need this flag to prevent us from getting back here, but
 643       // sometimes paranoia is good.
 644       did_trans_retry = true;
 645 
 646       // We wait for the thread to transition to a more usable state.
 647       for (int i = 1; i <= SuspendRetryCount; i++) {
 648         // We used to do an "os::yield_all(i)" call here with the intention
 649         // that yielding would increase on each retry. However, the parameter
 650         // is ignored on Linux which means the yield didn't scale up. Waiting
 651         // on the SR_lock below provides a much more predictable scale up for
 652         // the delay. It also provides a simple/direct point to check for any
 653         // safepoint requests from the VMThread
 654 
 655         // temporarily drops SR_lock while doing wait with safepoint check
 656         // (if we're a JavaThread - the WatcherThread can also call this)
 657         // and increase delay with each retry
 658         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 659 
 660         // check the actual thread state instead of what we saved above
 661         if (thread_state() != _thread_in_native_trans) {
 662           // the thread has transitioned to another thread state so
 663           // try all the checks (except this one) one more time.
 664           do_trans_retry = true;
 665           break;
 666         }
 667       } // end retry loop
 668 
 669 
 670     }
 671   } while (do_trans_retry);
 672 
 673   *bits |= 0x00000010;
 674   return false;
 675 }
 676 
 677 //
 678 // Wait for an external suspend request to complete (or be cancelled).
 679 // Returns true if the thread is externally suspended and false otherwise.
 680 //
 681 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 682        uint32_t *bits) {
 683   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 684                              false /* !called_by_wait */, bits);
 685 
 686   // local flag copies to minimize SR_lock hold time
 687   bool is_suspended;
 688   bool pending;
 689   uint32_t reset_bits;
 690 
 691   // set a marker so is_ext_suspend_completed() knows we are the caller
 692   *bits |= 0x00010000;
 693 
 694   // We use reset_bits to reinitialize the bits value at the top of
 695   // each retry loop. This allows the caller to make use of any
 696   // unused bits for their own marking purposes.
 697   reset_bits = *bits;
 698 
 699   {
 700     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 701     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 702                                             delay, bits);
 703     pending = is_external_suspend();
 704   }
 705   // must release SR_lock to allow suspension to complete
 706 
 707   if (!pending) {
 708     // A cancelled suspend request is the only false return from
 709     // is_ext_suspend_completed() that keeps us from entering the
 710     // retry loop.
 711     *bits |= 0x00020000;
 712     return false;
 713   }
 714 
 715   if (is_suspended) {
 716     *bits |= 0x00040000;
 717     return true;
 718   }
 719 
 720   for (int i = 1; i <= retries; i++) {
 721     *bits = reset_bits;  // reinit to only track last retry
 722 
 723     // We used to do an "os::yield_all(i)" call here with the intention
 724     // that yielding would increase on each retry. However, the parameter
 725     // is ignored on Linux which means the yield didn't scale up. Waiting
 726     // on the SR_lock below provides a much more predictable scale up for
 727     // the delay. It also provides a simple/direct point to check for any
 728     // safepoint requests from the VMThread
 729 
 730     {
 731       MutexLocker ml(SR_lock());
 732       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 733       // can also call this)  and increase delay with each retry
 734       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 735 
 736       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 737                                               delay, bits);
 738 
 739       // It is possible for the external suspend request to be cancelled
 740       // (by a resume) before the actual suspend operation is completed.
 741       // Refresh our local copy to see if we still need to wait.
 742       pending = is_external_suspend();
 743     }
 744 
 745     if (!pending) {
 746       // A cancelled suspend request is the only false return from
 747       // is_ext_suspend_completed() that keeps us from staying in the
 748       // retry loop.
 749       *bits |= 0x00080000;
 750       return false;
 751     }
 752 
 753     if (is_suspended) {
 754       *bits |= 0x00100000;
 755       return true;
 756     }
 757   } // end retry loop
 758 
 759   // thread did not suspend after all our retries
 760   *bits |= 0x00200000;
 761   return false;
 762 }
 763 
 764 #ifndef PRODUCT
 765 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 766 
 767   // This should not need to be atomic as the only way for simultaneous
 768   // updates is via interrupts. Even then this should be rare or non-existant
 769   // and we don't care that much anyway.
 770 
 771   int index = _jmp_ring_index;
 772   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 773   _jmp_ring[index]._target = (intptr_t) target;
 774   _jmp_ring[index]._instruction = (intptr_t) instr;
 775   _jmp_ring[index]._file = file;
 776   _jmp_ring[index]._line = line;
 777 }
 778 #endif /* PRODUCT */
 779 
 780 // Called by flat profiler
 781 // Callers have already called wait_for_ext_suspend_completion
 782 // The assertion for that is currently too complex to put here:
 783 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 784   bool gotframe = false;
 785   // self suspension saves needed state.
 786   if (has_last_Java_frame() && _anchor.walkable()) {
 787      *_fr = pd_last_frame();
 788      gotframe = true;
 789   }
 790   return gotframe;
 791 }
 792 
 793 void Thread::interrupt(Thread* thread) {
 794   trace("interrupt", thread);
 795   debug_only(check_for_dangling_thread_pointer(thread);)
 796   os::interrupt(thread);
 797 }
 798 
 799 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 800   trace("is_interrupted", thread);
 801   debug_only(check_for_dangling_thread_pointer(thread);)
 802   // Note:  If clear_interrupted==false, this simply fetches and
 803   // returns the value of the field osthread()->interrupted().
 804   return os::is_interrupted(thread, clear_interrupted);
 805 }
 806 
 807 
 808 // GC Support
 809 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 810   jint thread_parity = _oops_do_parity;
 811   if (thread_parity != strong_roots_parity) {
 812     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 813     if (res == thread_parity) {
 814       return true;
 815     } else {
 816       guarantee(res == strong_roots_parity, "Or else what?");
 817       assert(SharedHeap::heap()->workers()->active_workers() > 0,
 818          "Should only fail when parallel.");
 819       return false;
 820     }
 821   }
 822   assert(SharedHeap::heap()->workers()->active_workers() > 0,
 823          "Should only fail when parallel.");
 824   return false;
 825 }
 826 
 827 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
 828   active_handles()->oops_do(f);
 829   // Do oop for ThreadShadow
 830   f->do_oop((oop*)&_pending_exception);
 831   handle_area()->oops_do(f);
 832 }
 833 
 834 void Thread::nmethods_do(CodeBlobClosure* cf) {
 835   // no nmethods in a generic thread...
 836 }
 837 
 838 void Thread::metadata_do(void f(Metadata*)) {
 839   if (metadata_handles() != NULL) {
 840     for (int i = 0; i< metadata_handles()->length(); i++) {
 841       f(metadata_handles()->at(i));
 842     }
 843   }
 844 }
 845 
 846 void Thread::print_on(outputStream* st) const {
 847   // get_priority assumes osthread initialized
 848   if (osthread() != NULL) {
 849     int os_prio;
 850     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 851       st->print("os_prio=%d ", os_prio);
 852     }
 853     st->print("tid=" INTPTR_FORMAT " ", this);
 854     osthread()->print_on(st);
 855   }
 856   debug_only(if (WizardMode) print_owned_locks_on(st);)
 857 }
 858 
 859 // Thread::print_on_error() is called by fatal error handler. Don't use
 860 // any lock or allocate memory.
 861 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 862   if      (is_VM_thread())                  st->print("VMThread");
 863   else if (is_Compiler_thread())            st->print("CompilerThread");
 864   else if (is_Java_thread())                st->print("JavaThread");
 865   else if (is_GC_task_thread())             st->print("GCTaskThread");
 866   else if (is_Watcher_thread())             st->print("WatcherThread");
 867   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 868   else st->print("Thread");
 869 
 870   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 871             _stack_base - _stack_size, _stack_base);
 872 
 873   if (osthread()) {
 874     st->print(" [id=%d]", osthread()->thread_id());
 875   }
 876 }
 877 
 878 #ifdef ASSERT
 879 void Thread::print_owned_locks_on(outputStream* st) const {
 880   Monitor *cur = _owned_locks;
 881   if (cur == NULL) {
 882     st->print(" (no locks) ");
 883   } else {
 884     st->print_cr(" Locks owned:");
 885     while(cur) {
 886       cur->print_on(st);
 887       cur = cur->next();
 888     }
 889   }
 890 }
 891 
 892 static int ref_use_count  = 0;
 893 
 894 bool Thread::owns_locks_but_compiled_lock() const {
 895   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 896     if (cur != Compile_lock) return true;
 897   }
 898   return false;
 899 }
 900 
 901 
 902 #endif
 903 
 904 #ifndef PRODUCT
 905 
 906 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 907 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 908 // no threads which allow_vm_block's are held
 909 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 910     // Check if current thread is allowed to block at a safepoint
 911     if (!(_allow_safepoint_count == 0))
 912       fatal("Possible safepoint reached by thread that does not allow it");
 913     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 914       fatal("LEAF method calling lock?");
 915     }
 916 
 917 #ifdef ASSERT
 918     if (potential_vm_operation && is_Java_thread()
 919         && !Universe::is_bootstrapping()) {
 920       // Make sure we do not hold any locks that the VM thread also uses.
 921       // This could potentially lead to deadlocks
 922       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 923         // Threads_lock is special, since the safepoint synchronization will not start before this is
 924         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 925         // since it is used to transfer control between JavaThreads and the VMThread
 926         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
 927         if ( (cur->allow_vm_block() &&
 928               cur != Threads_lock &&
 929               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
 930               cur != VMOperationRequest_lock &&
 931               cur != VMOperationQueue_lock) ||
 932               cur->rank() == Mutex::special) {
 933           warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 934         }
 935       }
 936     }
 937 
 938     if (GCALotAtAllSafepoints) {
 939       // We could enter a safepoint here and thus have a gc
 940       InterfaceSupport::check_gc_alot();
 941     }
 942 #endif
 943 }
 944 #endif
 945 
 946 bool Thread::is_in_stack(address adr) const {
 947   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 948   address end = os::current_stack_pointer();
 949   // Allow non Java threads to call this without stack_base
 950   if (_stack_base == NULL) return true;
 951   if (stack_base() >= adr && adr >= end) return true;
 952 
 953   return false;
 954 }
 955 
 956 
 957 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 958 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 959 // used for compilation in the future. If that change is made, the need for these methods
 960 // should be revisited, and they should be removed if possible.
 961 
 962 bool Thread::is_lock_owned(address adr) const {
 963   return on_local_stack(adr);
 964 }
 965 
 966 bool Thread::set_as_starting_thread() {
 967  // NOTE: this must be called inside the main thread.
 968   return os::create_main_thread((JavaThread*)this);
 969 }
 970 
 971 static void initialize_class(Symbol* class_name, TRAPS) {
 972   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 973   InstanceKlass::cast(klass)->initialize(CHECK);
 974 }
 975 
 976 
 977 // Creates the initial ThreadGroup
 978 static Handle create_initial_thread_group(TRAPS) {
 979   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
 980   instanceKlassHandle klass (THREAD, k);
 981 
 982   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
 983   {
 984     JavaValue result(T_VOID);
 985     JavaCalls::call_special(&result,
 986                             system_instance,
 987                             klass,
 988                             vmSymbols::object_initializer_name(),
 989                             vmSymbols::void_method_signature(),
 990                             CHECK_NH);
 991   }
 992   Universe::set_system_thread_group(system_instance());
 993 
 994   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
 995   {
 996     JavaValue result(T_VOID);
 997     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 998     JavaCalls::call_special(&result,
 999                             main_instance,
1000                             klass,
1001                             vmSymbols::object_initializer_name(),
1002                             vmSymbols::threadgroup_string_void_signature(),
1003                             system_instance,
1004                             string,
1005                             CHECK_NH);
1006   }
1007   return main_instance;
1008 }
1009 
1010 // Creates the initial Thread
1011 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1012   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1013   instanceKlassHandle klass (THREAD, k);
1014   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1015 
1016   java_lang_Thread::set_thread(thread_oop(), thread);
1017   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1018   thread->set_threadObj(thread_oop());
1019 
1020   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1021 
1022   JavaValue result(T_VOID);
1023   JavaCalls::call_special(&result, thread_oop,
1024                                    klass,
1025                                    vmSymbols::object_initializer_name(),
1026                                    vmSymbols::threadgroup_string_void_signature(),
1027                                    thread_group,
1028                                    string,
1029                                    CHECK_NULL);
1030   return thread_oop();
1031 }
1032 
1033 static void call_initializeSystemClass(TRAPS) {
1034   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1035   instanceKlassHandle klass (THREAD, k);
1036 
1037   JavaValue result(T_VOID);
1038   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1039                                          vmSymbols::void_method_signature(), CHECK);
1040 }
1041 
1042 char java_runtime_name[128] = "";
1043 char java_runtime_version[128] = "";
1044 
1045 // extract the JRE name from sun.misc.Version.java_runtime_name
1046 static const char* get_java_runtime_name(TRAPS) {
1047   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1048                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1049   fieldDescriptor fd;
1050   bool found = k != NULL &&
1051                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1052                                                         vmSymbols::string_signature(), &fd);
1053   if (found) {
1054     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1055     if (name_oop == NULL)
1056       return NULL;
1057     const char* name = java_lang_String::as_utf8_string(name_oop,
1058                                                         java_runtime_name,
1059                                                         sizeof(java_runtime_name));
1060     return name;
1061   } else {
1062     return NULL;
1063   }
1064 }
1065 
1066 // extract the JRE version from sun.misc.Version.java_runtime_version
1067 static const char* get_java_runtime_version(TRAPS) {
1068   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1069                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1070   fieldDescriptor fd;
1071   bool found = k != NULL &&
1072                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1073                                                         vmSymbols::string_signature(), &fd);
1074   if (found) {
1075     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1076     if (name_oop == NULL)
1077       return NULL;
1078     const char* name = java_lang_String::as_utf8_string(name_oop,
1079                                                         java_runtime_version,
1080                                                         sizeof(java_runtime_version));
1081     return name;
1082   } else {
1083     return NULL;
1084   }
1085 }
1086 
1087 // General purpose hook into Java code, run once when the VM is initialized.
1088 // The Java library method itself may be changed independently from the VM.
1089 static void call_postVMInitHook(TRAPS) {
1090   Klass* k = SystemDictionary::PostVMInitHook_klass();
1091   instanceKlassHandle klass (THREAD, k);
1092   if (klass.not_null()) {
1093     JavaValue result(T_VOID);
1094     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1095                                            vmSymbols::void_method_signature(),
1096                                            CHECK);
1097   }
1098 }
1099 
1100 static void reset_vm_info_property(TRAPS) {
1101   // the vm info string
1102   ResourceMark rm(THREAD);
1103   const char *vm_info = VM_Version::vm_info_string();
1104 
1105   // java.lang.System class
1106   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1107   instanceKlassHandle klass (THREAD, k);
1108 
1109   // setProperty arguments
1110   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1111   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1112 
1113   // return value
1114   JavaValue r(T_OBJECT);
1115 
1116   // public static String setProperty(String key, String value);
1117   JavaCalls::call_static(&r,
1118                          klass,
1119                          vmSymbols::setProperty_name(),
1120                          vmSymbols::string_string_string_signature(),
1121                          key_str,
1122                          value_str,
1123                          CHECK);
1124 }
1125 
1126 
1127 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1128   assert(thread_group.not_null(), "thread group should be specified");
1129   assert(threadObj() == NULL, "should only create Java thread object once");
1130 
1131   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1132   instanceKlassHandle klass (THREAD, k);
1133   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1134 
1135   java_lang_Thread::set_thread(thread_oop(), this);
1136   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1137   set_threadObj(thread_oop());
1138 
1139   JavaValue result(T_VOID);
1140   if (thread_name != NULL) {
1141     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1142     // Thread gets assigned specified name and null target
1143     JavaCalls::call_special(&result,
1144                             thread_oop,
1145                             klass,
1146                             vmSymbols::object_initializer_name(),
1147                             vmSymbols::threadgroup_string_void_signature(),
1148                             thread_group, // Argument 1
1149                             name,         // Argument 2
1150                             THREAD);
1151   } else {
1152     // Thread gets assigned name "Thread-nnn" and null target
1153     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1154     JavaCalls::call_special(&result,
1155                             thread_oop,
1156                             klass,
1157                             vmSymbols::object_initializer_name(),
1158                             vmSymbols::threadgroup_runnable_void_signature(),
1159                             thread_group, // Argument 1
1160                             Handle(),     // Argument 2
1161                             THREAD);
1162   }
1163 
1164 
1165   if (daemon) {
1166       java_lang_Thread::set_daemon(thread_oop());
1167   }
1168 
1169   if (HAS_PENDING_EXCEPTION) {
1170     return;
1171   }
1172 
1173   KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1174   Handle threadObj(this, this->threadObj());
1175 
1176   JavaCalls::call_special(&result,
1177                          thread_group,
1178                          group,
1179                          vmSymbols::add_method_name(),
1180                          vmSymbols::thread_void_signature(),
1181                          threadObj,          // Arg 1
1182                          THREAD);
1183 
1184 
1185 }
1186 
1187 // NamedThread --  non-JavaThread subclasses with multiple
1188 // uniquely named instances should derive from this.
1189 NamedThread::NamedThread() : Thread() {
1190   _name = NULL;
1191   _processed_thread = NULL;
1192 }
1193 
1194 NamedThread::~NamedThread() {
1195   if (_name != NULL) {
1196     FREE_C_HEAP_ARRAY(char, _name, mtThread);
1197     _name = NULL;
1198   }
1199 }
1200 
1201 void NamedThread::set_name(const char* format, ...) {
1202   guarantee(_name == NULL, "Only get to set name once.");
1203   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1204   guarantee(_name != NULL, "alloc failure");
1205   va_list ap;
1206   va_start(ap, format);
1207   jio_vsnprintf(_name, max_name_len, format, ap);
1208   va_end(ap);
1209 }
1210 
1211 // ======= WatcherThread ========
1212 
1213 // The watcher thread exists to simulate timer interrupts.  It should
1214 // be replaced by an abstraction over whatever native support for
1215 // timer interrupts exists on the platform.
1216 
1217 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1218 bool WatcherThread::_startable = false;
1219 volatile bool  WatcherThread::_should_terminate = false;
1220 
1221 WatcherThread::WatcherThread() : Thread() {
1222   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1223   if (os::create_thread(this, os::watcher_thread)) {
1224     _watcher_thread = this;
1225 
1226     // Set the watcher thread to the highest OS priority which should not be
1227     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1228     // is created. The only normal thread using this priority is the reference
1229     // handler thread, which runs for very short intervals only.
1230     // If the VMThread's priority is not lower than the WatcherThread profiling
1231     // will be inaccurate.
1232     os::set_priority(this, MaxPriority);
1233     if (!DisableStartThread) {
1234       os::start_thread(this);
1235     }
1236   }
1237 }
1238 
1239 int WatcherThread::sleep() const {
1240   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1241 
1242   // remaining will be zero if there are no tasks,
1243   // causing the WatcherThread to sleep until a task is
1244   // enrolled
1245   int remaining = PeriodicTask::time_to_wait();
1246   int time_slept = 0;
1247 
1248   // we expect this to timeout - we only ever get unparked when
1249   // we should terminate or when a new task has been enrolled
1250   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1251 
1252   jlong time_before_loop = os::javaTimeNanos();
1253 
1254   for (;;) {
1255     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1256     jlong now = os::javaTimeNanos();
1257 
1258     if (remaining == 0) {
1259         // if we didn't have any tasks we could have waited for a long time
1260         // consider the time_slept zero and reset time_before_loop
1261         time_slept = 0;
1262         time_before_loop = now;
1263     } else {
1264         // need to recalulate since we might have new tasks in _tasks
1265         time_slept = (int) ((now - time_before_loop) / 1000000);
1266     }
1267 
1268     // Change to task list or spurious wakeup of some kind
1269     if (timedout || _should_terminate) {
1270         break;
1271     }
1272 
1273     remaining = PeriodicTask::time_to_wait();
1274     if (remaining == 0) {
1275         // Last task was just disenrolled so loop around and wait until
1276         // another task gets enrolled
1277         continue;
1278     }
1279 
1280     remaining -= time_slept;
1281     if (remaining <= 0)
1282       break;
1283   }
1284 
1285   return time_slept;
1286 }
1287 
1288 void WatcherThread::run() {
1289   assert(this == watcher_thread(), "just checking");
1290 
1291   this->record_stack_base_and_size();
1292   this->initialize_thread_local_storage();
1293   this->set_active_handles(JNIHandleBlock::allocate_block());
1294   while(!_should_terminate) {
1295     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1296     assert(watcher_thread() == this,  "thread consistency check");
1297 
1298     // Calculate how long it'll be until the next PeriodicTask work
1299     // should be done, and sleep that amount of time.
1300     int time_waited = sleep();
1301 
1302     if (is_error_reported()) {
1303       // A fatal error has happened, the error handler(VMError::report_and_die)
1304       // should abort JVM after creating an error log file. However in some
1305       // rare cases, the error handler itself might deadlock. Here we try to
1306       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1307       //
1308       // This code is in WatcherThread because WatcherThread wakes up
1309       // periodically so the fatal error handler doesn't need to do anything;
1310       // also because the WatcherThread is less likely to crash than other
1311       // threads.
1312 
1313       for (;;) {
1314         if (!ShowMessageBoxOnError
1315          && (OnError == NULL || OnError[0] == '\0')
1316          && Arguments::abort_hook() == NULL) {
1317              os::sleep(this, 2 * 60 * 1000, false);
1318              fdStream err(defaultStream::output_fd());
1319              err.print_raw_cr("# [ timer expired, abort... ]");
1320              // skip atexit/vm_exit/vm_abort hooks
1321              os::die();
1322         }
1323 
1324         // Wake up 5 seconds later, the fatal handler may reset OnError or
1325         // ShowMessageBoxOnError when it is ready to abort.
1326         os::sleep(this, 5 * 1000, false);
1327       }
1328     }
1329 
1330     PeriodicTask::real_time_tick(time_waited);
1331   }
1332 
1333   // Signal that it is terminated
1334   {
1335     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1336     _watcher_thread = NULL;
1337     Terminator_lock->notify();
1338   }
1339 
1340   // Thread destructor usually does this..
1341   ThreadLocalStorage::set_thread(NULL);
1342 }
1343 
1344 void WatcherThread::start() {
1345   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1346 
1347   if (watcher_thread() == NULL && _startable) {
1348     _should_terminate = false;
1349     // Create the single instance of WatcherThread
1350     new WatcherThread();
1351   }
1352 }
1353 
1354 void WatcherThread::make_startable() {
1355   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1356   _startable = true;
1357 }
1358 
1359 void WatcherThread::stop() {
1360   {
1361     MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1362     _should_terminate = true;
1363     OrderAccess::fence();  // ensure WatcherThread sees update in main loop
1364 
1365     WatcherThread* watcher = watcher_thread();
1366     if (watcher != NULL)
1367       watcher->unpark();
1368   }
1369 
1370   // it is ok to take late safepoints here, if needed
1371   MutexLocker mu(Terminator_lock);
1372 
1373   while(watcher_thread() != NULL) {
1374     // This wait should make safepoint checks, wait without a timeout,
1375     // and wait as a suspend-equivalent condition.
1376     //
1377     // Note: If the FlatProfiler is running, then this thread is waiting
1378     // for the WatcherThread to terminate and the WatcherThread, via the
1379     // FlatProfiler task, is waiting for the external suspend request on
1380     // this thread to complete. wait_for_ext_suspend_completion() will
1381     // eventually timeout, but that takes time. Making this wait a
1382     // suspend-equivalent condition solves that timeout problem.
1383     //
1384     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1385                           Mutex::_as_suspend_equivalent_flag);
1386   }
1387 }
1388 
1389 void WatcherThread::unpark() {
1390   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1391   PeriodicTask_lock->notify();
1392 }
1393 
1394 void WatcherThread::print_on(outputStream* st) const {
1395   st->print("\"%s\" ", name());
1396   Thread::print_on(st);
1397   st->cr();
1398 }
1399 
1400 // ======= JavaThread ========
1401 
1402 // A JavaThread is a normal Java thread
1403 
1404 void JavaThread::initialize() {
1405   // Initialize fields
1406 
1407   // Set the claimed par_id to -1 (ie not claiming any par_ids)
1408   set_claimed_par_id(-1);
1409 
1410   set_saved_exception_pc(NULL);
1411   set_threadObj(NULL);
1412   _anchor.clear();
1413   set_entry_point(NULL);
1414   set_jni_functions(jni_functions());
1415   set_callee_target(NULL);
1416   set_vm_result(NULL);
1417   set_vm_result_2(NULL);
1418   set_vframe_array_head(NULL);
1419   set_vframe_array_last(NULL);
1420   set_deferred_locals(NULL);
1421   set_deopt_mark(NULL);
1422   set_deopt_nmethod(NULL);
1423   clear_must_deopt_id();
1424   set_monitor_chunks(NULL);
1425   set_next(NULL);
1426   set_thread_state(_thread_new);
1427 #if INCLUDE_NMT
1428   set_recorder(NULL);
1429 #endif
1430   _terminated = _not_terminated;
1431   _privileged_stack_top = NULL;
1432   _array_for_gc = NULL;
1433   _suspend_equivalent = false;
1434   _in_deopt_handler = 0;
1435   _doing_unsafe_access = false;
1436   _stack_guard_state = stack_guard_unused;
1437   _exception_oop = NULL;
1438   _exception_pc  = 0;
1439   _exception_handler_pc = 0;
1440   _is_method_handle_return = 0;
1441   _jvmti_thread_state= NULL;
1442   _should_post_on_exceptions_flag = JNI_FALSE;
1443   _jvmti_get_loaded_classes_closure = NULL;
1444   _interp_only_mode    = 0;
1445   _special_runtime_exit_condition = _no_async_condition;
1446   _pending_async_exception = NULL;
1447   _is_compiling = false;
1448   _thread_stat = NULL;
1449   _thread_stat = new ThreadStatistics();
1450   _blocked_on_compilation = false;
1451   _jni_active_critical = 0;
1452   _do_not_unlock_if_synchronized = false;
1453   _cached_monitor_info = NULL;
1454   _parker = Parker::Allocate(this) ;
1455 
1456 #ifndef PRODUCT
1457   _jmp_ring_index = 0;
1458   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1459     record_jump(NULL, NULL, NULL, 0);
1460   }
1461 #endif /* PRODUCT */
1462 
1463   set_thread_profiler(NULL);
1464   if (FlatProfiler::is_active()) {
1465     // This is where we would decide to either give each thread it's own profiler
1466     // or use one global one from FlatProfiler,
1467     // or up to some count of the number of profiled threads, etc.
1468     ThreadProfiler* pp = new ThreadProfiler();
1469     pp->engage();
1470     set_thread_profiler(pp);
1471   }
1472 
1473   // Setup safepoint state info for this thread
1474   ThreadSafepointState::create(this);
1475 
1476   debug_only(_java_call_counter = 0);
1477 
1478   // JVMTI PopFrame support
1479   _popframe_condition = popframe_inactive;
1480   _popframe_preserved_args = NULL;
1481   _popframe_preserved_args_size = 0;
1482 
1483   pd_initialize();
1484 }
1485 
1486 #if INCLUDE_ALL_GCS
1487 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1488 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1489 #endif // INCLUDE_ALL_GCS
1490 
1491 JavaThread::JavaThread(bool is_attaching_via_jni) :
1492   Thread()
1493 #if INCLUDE_ALL_GCS
1494   , _satb_mark_queue(&_satb_mark_queue_set),
1495   _dirty_card_queue(&_dirty_card_queue_set)
1496 #endif // INCLUDE_ALL_GCS
1497 {
1498   initialize();
1499   if (is_attaching_via_jni) {
1500     _jni_attach_state = _attaching_via_jni;
1501   } else {
1502     _jni_attach_state = _not_attaching_via_jni;
1503   }
1504   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1505   _safepoint_visible = false;
1506 }
1507 
1508 bool JavaThread::reguard_stack(address cur_sp) {
1509   if (_stack_guard_state != stack_guard_yellow_disabled) {
1510     return true; // Stack already guarded or guard pages not needed.
1511   }
1512 
1513   if (register_stack_overflow()) {
1514     // For those architectures which have separate register and
1515     // memory stacks, we must check the register stack to see if
1516     // it has overflowed.
1517     return false;
1518   }
1519 
1520   // Java code never executes within the yellow zone: the latter is only
1521   // there to provoke an exception during stack banging.  If java code
1522   // is executing there, either StackShadowPages should be larger, or
1523   // some exception code in c1, c2 or the interpreter isn't unwinding
1524   // when it should.
1525   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1526 
1527   enable_stack_yellow_zone();
1528   return true;
1529 }
1530 
1531 bool JavaThread::reguard_stack(void) {
1532   return reguard_stack(os::current_stack_pointer());
1533 }
1534 
1535 
1536 void JavaThread::block_if_vm_exited() {
1537   if (_terminated == _vm_exited) {
1538     // _vm_exited is set at safepoint, and Threads_lock is never released
1539     // we will block here forever
1540     Threads_lock->lock_without_safepoint_check();
1541     ShouldNotReachHere();
1542   }
1543 }
1544 
1545 
1546 // Remove this ifdef when C1 is ported to the compiler interface.
1547 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1548 
1549 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1550   Thread()
1551 #if INCLUDE_ALL_GCS
1552   , _satb_mark_queue(&_satb_mark_queue_set),
1553   _dirty_card_queue(&_dirty_card_queue_set)
1554 #endif // INCLUDE_ALL_GCS
1555 {
1556   if (TraceThreadEvents) {
1557     tty->print_cr("creating thread %p", this);
1558   }
1559   initialize();
1560   _jni_attach_state = _not_attaching_via_jni;
1561   set_entry_point(entry_point);
1562   // Create the native thread itself.
1563   // %note runtime_23
1564   os::ThreadType thr_type = os::java_thread;
1565   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1566                                                      os::java_thread;
1567   os::create_thread(this, thr_type, stack_sz);
1568   _safepoint_visible = false;
1569   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1570   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1571   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1572   // the exception consists of creating the exception object & initializing it, initialization
1573   // will leave the VM via a JavaCall and then all locks must be unlocked).
1574   //
1575   // The thread is still suspended when we reach here. Thread must be explicit started
1576   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1577   // by calling Threads:add. The reason why this is not done here, is because the thread
1578   // object must be fully initialized (take a look at JVM_Start)
1579 }
1580 
1581 JavaThread::~JavaThread() {
1582   if (TraceThreadEvents) {
1583       tty->print_cr("terminate thread %p", this);
1584   }
1585 
1586   // By now, this thread should already be invisible to safepoint,
1587   // and its per-thread recorder also collected.
1588   assert(!is_safepoint_visible(), "wrong state");
1589 #if INCLUDE_NMT
1590   assert(get_recorder() == NULL, "Already collected");
1591 #endif // INCLUDE_NMT
1592 
1593   // JSR166 -- return the parker to the free list
1594   Parker::Release(_parker);
1595   _parker = NULL ;
1596 
1597   // Free any remaining  previous UnrollBlock
1598   vframeArray* old_array = vframe_array_last();
1599 
1600   if (old_array != NULL) {
1601     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1602     old_array->set_unroll_block(NULL);
1603     delete old_info;
1604     delete old_array;
1605   }
1606 
1607   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1608   if (deferred != NULL) {
1609     // This can only happen if thread is destroyed before deoptimization occurs.
1610     assert(deferred->length() != 0, "empty array!");
1611     do {
1612       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1613       deferred->remove_at(0);
1614       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1615       delete dlv;
1616     } while (deferred->length() != 0);
1617     delete deferred;
1618   }
1619 
1620   // All Java related clean up happens in exit
1621   ThreadSafepointState::destroy(this);
1622   if (_thread_profiler != NULL) delete _thread_profiler;
1623   if (_thread_stat != NULL) delete _thread_stat;
1624 }
1625 
1626 
1627 // The first routine called by a new Java thread
1628 void JavaThread::run() {
1629   // initialize thread-local alloc buffer related fields
1630   this->initialize_tlab();
1631 
1632   // used to test validitity of stack trace backs
1633   this->record_base_of_stack_pointer();
1634 
1635   // Record real stack base and size.
1636   this->record_stack_base_and_size();
1637 
1638   // Initialize thread local storage; set before calling MutexLocker
1639   this->initialize_thread_local_storage();
1640 
1641   this->create_stack_guard_pages();
1642 
1643   this->cache_global_variables();
1644 
1645   // Thread is now sufficient initialized to be handled by the safepoint code as being
1646   // in the VM. Change thread state from _thread_new to _thread_in_vm
1647   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1648 
1649   assert(JavaThread::current() == this, "sanity check");
1650   assert(!Thread::current()->owns_locks(), "sanity check");
1651 
1652   DTRACE_THREAD_PROBE(start, this);
1653 
1654   // This operation might block. We call that after all safepoint checks for a new thread has
1655   // been completed.
1656   this->set_active_handles(JNIHandleBlock::allocate_block());
1657 
1658   if (JvmtiExport::should_post_thread_life()) {
1659     JvmtiExport::post_thread_start(this);
1660   }
1661 
1662   EVENT_BEGIN(TraceEventThreadStart, event);
1663   EVENT_COMMIT(event,
1664      EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1665 
1666   // We call another function to do the rest so we are sure that the stack addresses used
1667   // from there will be lower than the stack base just computed
1668   thread_main_inner();
1669 
1670   // Note, thread is no longer valid at this point!
1671 }
1672 
1673 
1674 void JavaThread::thread_main_inner() {
1675   assert(JavaThread::current() == this, "sanity check");
1676   assert(this->threadObj() != NULL, "just checking");
1677 
1678   // Execute thread entry point unless this thread has a pending exception
1679   // or has been stopped before starting.
1680   // Note: Due to JVM_StopThread we can have pending exceptions already!
1681   if (!this->has_pending_exception() &&
1682       !java_lang_Thread::is_stillborn(this->threadObj())) {
1683     {
1684       ResourceMark rm(this);
1685       this->set_native_thread_name(this->get_thread_name());
1686     }
1687     HandleMark hm(this);
1688     this->entry_point()(this, this);
1689   }
1690 
1691   DTRACE_THREAD_PROBE(stop, this);
1692 
1693   this->exit(false);
1694   delete this;
1695 }
1696 
1697 
1698 static void ensure_join(JavaThread* thread) {
1699   // We do not need to grap the Threads_lock, since we are operating on ourself.
1700   Handle threadObj(thread, thread->threadObj());
1701   assert(threadObj.not_null(), "java thread object must exist");
1702   ObjectLocker lock(threadObj, thread);
1703   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1704   thread->clear_pending_exception();
1705   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1706   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1707   // Clear the native thread instance - this makes isAlive return false and allows the join()
1708   // to complete once we've done the notify_all below
1709   java_lang_Thread::set_thread(threadObj(), NULL);
1710   lock.notify_all(thread);
1711   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1712   thread->clear_pending_exception();
1713 }
1714 
1715 
1716 // For any new cleanup additions, please check to see if they need to be applied to
1717 // cleanup_failed_attach_current_thread as well.
1718 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1719   assert(this == JavaThread::current(),  "thread consistency check");
1720 
1721   HandleMark hm(this);
1722   Handle uncaught_exception(this, this->pending_exception());
1723   this->clear_pending_exception();
1724   Handle threadObj(this, this->threadObj());
1725   assert(threadObj.not_null(), "Java thread object should be created");
1726 
1727   if (get_thread_profiler() != NULL) {
1728     get_thread_profiler()->disengage();
1729     ResourceMark rm;
1730     get_thread_profiler()->print(get_thread_name());
1731   }
1732 
1733 
1734   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1735   {
1736     EXCEPTION_MARK;
1737 
1738     CLEAR_PENDING_EXCEPTION;
1739   }
1740   // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1741   // has to be fixed by a runtime query method
1742   if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1743     // JSR-166: change call from from ThreadGroup.uncaughtException to
1744     // java.lang.Thread.dispatchUncaughtException
1745     if (uncaught_exception.not_null()) {
1746       Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1747       {
1748         EXCEPTION_MARK;
1749         // Check if the method Thread.dispatchUncaughtException() exists. If so
1750         // call it.  Otherwise we have an older library without the JSR-166 changes,
1751         // so call ThreadGroup.uncaughtException()
1752         KlassHandle recvrKlass(THREAD, threadObj->klass());
1753         CallInfo callinfo;
1754         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1755         LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1756                                            vmSymbols::dispatchUncaughtException_name(),
1757                                            vmSymbols::throwable_void_signature(),
1758                                            KlassHandle(), false, false, THREAD);
1759         CLEAR_PENDING_EXCEPTION;
1760         methodHandle method = callinfo.selected_method();
1761         if (method.not_null()) {
1762           JavaValue result(T_VOID);
1763           JavaCalls::call_virtual(&result,
1764                                   threadObj, thread_klass,
1765                                   vmSymbols::dispatchUncaughtException_name(),
1766                                   vmSymbols::throwable_void_signature(),
1767                                   uncaught_exception,
1768                                   THREAD);
1769         } else {
1770           KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1771           JavaValue result(T_VOID);
1772           JavaCalls::call_virtual(&result,
1773                                   group, thread_group,
1774                                   vmSymbols::uncaughtException_name(),
1775                                   vmSymbols::thread_throwable_void_signature(),
1776                                   threadObj,           // Arg 1
1777                                   uncaught_exception,  // Arg 2
1778                                   THREAD);
1779         }
1780         if (HAS_PENDING_EXCEPTION) {
1781           ResourceMark rm(this);
1782           jio_fprintf(defaultStream::error_stream(),
1783                 "\nException: %s thrown from the UncaughtExceptionHandler"
1784                 " in thread \"%s\"\n",
1785                 pending_exception()->klass()->external_name(),
1786                 get_thread_name());
1787           CLEAR_PENDING_EXCEPTION;
1788         }
1789       }
1790     }
1791 
1792     // Called before the java thread exit since we want to read info
1793     // from java_lang_Thread object
1794     EVENT_BEGIN(TraceEventThreadEnd, event);
1795     EVENT_COMMIT(event,
1796         EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1797 
1798     // Call after last event on thread
1799     EVENT_THREAD_EXIT(this);
1800 
1801     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1802     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1803     // is deprecated anyhow.
1804     { int count = 3;
1805       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1806         EXCEPTION_MARK;
1807         JavaValue result(T_VOID);
1808         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1809         JavaCalls::call_virtual(&result,
1810                               threadObj, thread_klass,
1811                               vmSymbols::exit_method_name(),
1812                               vmSymbols::void_method_signature(),
1813                               THREAD);
1814         CLEAR_PENDING_EXCEPTION;
1815       }
1816     }
1817 
1818     // notify JVMTI
1819     if (JvmtiExport::should_post_thread_life()) {
1820       JvmtiExport::post_thread_end(this);
1821     }
1822 
1823     // We have notified the agents that we are exiting, before we go on,
1824     // we must check for a pending external suspend request and honor it
1825     // in order to not surprise the thread that made the suspend request.
1826     while (true) {
1827       {
1828         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1829         if (!is_external_suspend()) {
1830           set_terminated(_thread_exiting);
1831           ThreadService::current_thread_exiting(this);
1832           break;
1833         }
1834         // Implied else:
1835         // Things get a little tricky here. We have a pending external
1836         // suspend request, but we are holding the SR_lock so we
1837         // can't just self-suspend. So we temporarily drop the lock
1838         // and then self-suspend.
1839       }
1840 
1841       ThreadBlockInVM tbivm(this);
1842       java_suspend_self();
1843 
1844       // We're done with this suspend request, but we have to loop around
1845       // and check again. Eventually we will get SR_lock without a pending
1846       // external suspend request and will be able to mark ourselves as
1847       // exiting.
1848     }
1849     // no more external suspends are allowed at this point
1850   } else {
1851     // before_exit() has already posted JVMTI THREAD_END events
1852   }
1853 
1854   // Notify waiters on thread object. This has to be done after exit() is called
1855   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1856   // group should have the destroyed bit set before waiters are notified).
1857   ensure_join(this);
1858   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1859 
1860   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1861   // held by this thread must be released.  A detach operation must only
1862   // get here if there are no Java frames on the stack.  Therefore, any
1863   // owned monitors at this point MUST be JNI-acquired monitors which are
1864   // pre-inflated and in the monitor cache.
1865   //
1866   // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1867   if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1868     assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1869     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1870     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1871   }
1872 
1873   // These things needs to be done while we are still a Java Thread. Make sure that thread
1874   // is in a consistent state, in case GC happens
1875   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1876 
1877   if (active_handles() != NULL) {
1878     JNIHandleBlock* block = active_handles();
1879     set_active_handles(NULL);
1880     JNIHandleBlock::release_block(block);
1881   }
1882 
1883   if (free_handle_block() != NULL) {
1884     JNIHandleBlock* block = free_handle_block();
1885     set_free_handle_block(NULL);
1886     JNIHandleBlock::release_block(block);
1887   }
1888 
1889   // These have to be removed while this is still a valid thread.
1890   remove_stack_guard_pages();
1891 
1892   if (UseTLAB) {
1893     tlab().make_parsable(true);  // retire TLAB
1894   }
1895 
1896   if (JvmtiEnv::environments_might_exist()) {
1897     JvmtiExport::cleanup_thread(this);
1898   }
1899 
1900   // We must flush any deferred card marks before removing a thread from
1901   // the list of active threads.
1902   Universe::heap()->flush_deferred_store_barrier(this);
1903   assert(deferred_card_mark().is_empty(), "Should have been flushed");
1904 
1905 #if INCLUDE_ALL_GCS
1906   // We must flush the G1-related buffers before removing a thread
1907   // from the list of active threads. We must do this after any deferred
1908   // card marks have been flushed (above) so that any entries that are
1909   // added to the thread's dirty card queue as a result are not lost.
1910   if (UseG1GC) {
1911     flush_barrier_queues();
1912   }
1913 #endif // INCLUDE_ALL_GCS
1914 
1915   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1916   Threads::remove(this);
1917 }
1918 
1919 #if INCLUDE_ALL_GCS
1920 // Flush G1-related queues.
1921 void JavaThread::flush_barrier_queues() {
1922   satb_mark_queue().flush();
1923   dirty_card_queue().flush();
1924 }
1925 
1926 void JavaThread::initialize_queues() {
1927   assert(!SafepointSynchronize::is_at_safepoint(),
1928          "we should not be at a safepoint");
1929 
1930   ObjPtrQueue& satb_queue = satb_mark_queue();
1931   SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1932   // The SATB queue should have been constructed with its active
1933   // field set to false.
1934   assert(!satb_queue.is_active(), "SATB queue should not be active");
1935   assert(satb_queue.is_empty(), "SATB queue should be empty");
1936   // If we are creating the thread during a marking cycle, we should
1937   // set the active field of the SATB queue to true.
1938   if (satb_queue_set.is_active()) {
1939     satb_queue.set_active(true);
1940   }
1941 
1942   DirtyCardQueue& dirty_queue = dirty_card_queue();
1943   // The dirty card queue should have been constructed with its
1944   // active field set to true.
1945   assert(dirty_queue.is_active(), "dirty card queue should be active");
1946 }
1947 #endif // INCLUDE_ALL_GCS
1948 
1949 void JavaThread::cleanup_failed_attach_current_thread() {
1950   if (get_thread_profiler() != NULL) {
1951     get_thread_profiler()->disengage();
1952     ResourceMark rm;
1953     get_thread_profiler()->print(get_thread_name());
1954   }
1955 
1956   if (active_handles() != NULL) {
1957     JNIHandleBlock* block = active_handles();
1958     set_active_handles(NULL);
1959     JNIHandleBlock::release_block(block);
1960   }
1961 
1962   if (free_handle_block() != NULL) {
1963     JNIHandleBlock* block = free_handle_block();
1964     set_free_handle_block(NULL);
1965     JNIHandleBlock::release_block(block);
1966   }
1967 
1968   // These have to be removed while this is still a valid thread.
1969   remove_stack_guard_pages();
1970 
1971   if (UseTLAB) {
1972     tlab().make_parsable(true);  // retire TLAB, if any
1973   }
1974 
1975 #if INCLUDE_ALL_GCS
1976   if (UseG1GC) {
1977     flush_barrier_queues();
1978   }
1979 #endif // INCLUDE_ALL_GCS
1980 
1981   Threads::remove(this);
1982   delete this;
1983 }
1984 
1985 
1986 
1987 
1988 JavaThread* JavaThread::active() {
1989   Thread* thread = ThreadLocalStorage::thread();
1990   assert(thread != NULL, "just checking");
1991   if (thread->is_Java_thread()) {
1992     return (JavaThread*) thread;
1993   } else {
1994     assert(thread->is_VM_thread(), "this must be a vm thread");
1995     VM_Operation* op = ((VMThread*) thread)->vm_operation();
1996     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1997     assert(ret->is_Java_thread(), "must be a Java thread");
1998     return ret;
1999   }
2000 }
2001 
2002 bool JavaThread::is_lock_owned(address adr) const {
2003   if (Thread::is_lock_owned(adr)) return true;
2004 
2005   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2006     if (chunk->contains(adr)) return true;
2007   }
2008 
2009   return false;
2010 }
2011 
2012 
2013 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2014   chunk->set_next(monitor_chunks());
2015   set_monitor_chunks(chunk);
2016 }
2017 
2018 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2019   guarantee(monitor_chunks() != NULL, "must be non empty");
2020   if (monitor_chunks() == chunk) {
2021     set_monitor_chunks(chunk->next());
2022   } else {
2023     MonitorChunk* prev = monitor_chunks();
2024     while (prev->next() != chunk) prev = prev->next();
2025     prev->set_next(chunk->next());
2026   }
2027 }
2028 
2029 // JVM support.
2030 
2031 // Note: this function shouldn't block if it's called in
2032 // _thread_in_native_trans state (such as from
2033 // check_special_condition_for_native_trans()).
2034 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2035 
2036   if (has_last_Java_frame() && has_async_condition()) {
2037     // If we are at a polling page safepoint (not a poll return)
2038     // then we must defer async exception because live registers
2039     // will be clobbered by the exception path. Poll return is
2040     // ok because the call we a returning from already collides
2041     // with exception handling registers and so there is no issue.
2042     // (The exception handling path kills call result registers but
2043     //  this is ok since the exception kills the result anyway).
2044 
2045     if (is_at_poll_safepoint()) {
2046       // if the code we are returning to has deoptimized we must defer
2047       // the exception otherwise live registers get clobbered on the
2048       // exception path before deoptimization is able to retrieve them.
2049       //
2050       RegisterMap map(this, false);
2051       frame caller_fr = last_frame().sender(&map);
2052       assert(caller_fr.is_compiled_frame(), "what?");
2053       if (caller_fr.is_deoptimized_frame()) {
2054         if (TraceExceptions) {
2055           ResourceMark rm;
2056           tty->print_cr("deferred async exception at compiled safepoint");
2057         }
2058         return;
2059       }
2060     }
2061   }
2062 
2063   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2064   if (condition == _no_async_condition) {
2065     // Conditions have changed since has_special_runtime_exit_condition()
2066     // was called:
2067     // - if we were here only because of an external suspend request,
2068     //   then that was taken care of above (or cancelled) so we are done
2069     // - if we were here because of another async request, then it has
2070     //   been cleared between the has_special_runtime_exit_condition()
2071     //   and now so again we are done
2072     return;
2073   }
2074 
2075   // Check for pending async. exception
2076   if (_pending_async_exception != NULL) {
2077     // Only overwrite an already pending exception, if it is not a threadDeath.
2078     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2079 
2080       // We cannot call Exceptions::_throw(...) here because we cannot block
2081       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2082 
2083       if (TraceExceptions) {
2084         ResourceMark rm;
2085         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2086         if (has_last_Java_frame() ) {
2087           frame f = last_frame();
2088           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2089         }
2090         tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2091       }
2092       _pending_async_exception = NULL;
2093       clear_has_async_exception();
2094     }
2095   }
2096 
2097   if (check_unsafe_error &&
2098       condition == _async_unsafe_access_error && !has_pending_exception()) {
2099     condition = _no_async_condition;  // done
2100     switch (thread_state()) {
2101     case _thread_in_vm:
2102       {
2103         JavaThread* THREAD = this;
2104         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2105       }
2106     case _thread_in_native:
2107       {
2108         ThreadInVMfromNative tiv(this);
2109         JavaThread* THREAD = this;
2110         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2111       }
2112     case _thread_in_Java:
2113       {
2114         ThreadInVMfromJava tiv(this);
2115         JavaThread* THREAD = this;
2116         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2117       }
2118     default:
2119       ShouldNotReachHere();
2120     }
2121   }
2122 
2123   assert(condition == _no_async_condition || has_pending_exception() ||
2124          (!check_unsafe_error && condition == _async_unsafe_access_error),
2125          "must have handled the async condition, if no exception");
2126 }
2127 
2128 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2129   //
2130   // Check for pending external suspend. Internal suspend requests do
2131   // not use handle_special_runtime_exit_condition().
2132   // If JNIEnv proxies are allowed, don't self-suspend if the target
2133   // thread is not the current thread. In older versions of jdbx, jdbx
2134   // threads could call into the VM with another thread's JNIEnv so we
2135   // can be here operating on behalf of a suspended thread (4432884).
2136   bool do_self_suspend = is_external_suspend_with_lock();
2137   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2138     //
2139     // Because thread is external suspended the safepoint code will count
2140     // thread as at a safepoint. This can be odd because we can be here
2141     // as _thread_in_Java which would normally transition to _thread_blocked
2142     // at a safepoint. We would like to mark the thread as _thread_blocked
2143     // before calling java_suspend_self like all other callers of it but
2144     // we must then observe proper safepoint protocol. (We can't leave
2145     // _thread_blocked with a safepoint in progress). However we can be
2146     // here as _thread_in_native_trans so we can't use a normal transition
2147     // constructor/destructor pair because they assert on that type of
2148     // transition. We could do something like:
2149     //
2150     // JavaThreadState state = thread_state();
2151     // set_thread_state(_thread_in_vm);
2152     // {
2153     //   ThreadBlockInVM tbivm(this);
2154     //   java_suspend_self()
2155     // }
2156     // set_thread_state(_thread_in_vm_trans);
2157     // if (safepoint) block;
2158     // set_thread_state(state);
2159     //
2160     // but that is pretty messy. Instead we just go with the way the
2161     // code has worked before and note that this is the only path to
2162     // java_suspend_self that doesn't put the thread in _thread_blocked
2163     // mode.
2164 
2165     frame_anchor()->make_walkable(this);
2166     java_suspend_self();
2167 
2168     // We might be here for reasons in addition to the self-suspend request
2169     // so check for other async requests.
2170   }
2171 
2172   if (check_asyncs) {
2173     check_and_handle_async_exceptions();
2174   }
2175 }
2176 
2177 void JavaThread::send_thread_stop(oop java_throwable)  {
2178   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2179   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2180   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2181 
2182   // Do not throw asynchronous exceptions against the compiler thread
2183   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2184   if (is_Compiler_thread()) return;
2185 
2186   {
2187     // Actually throw the Throwable against the target Thread - however
2188     // only if there is no thread death exception installed already.
2189     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2190       // If the topmost frame is a runtime stub, then we are calling into
2191       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2192       // must deoptimize the caller before continuing, as the compiled  exception handler table
2193       // may not be valid
2194       if (has_last_Java_frame()) {
2195         frame f = last_frame();
2196         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2197           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2198           RegisterMap reg_map(this, UseBiasedLocking);
2199           frame compiled_frame = f.sender(&reg_map);
2200           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2201             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2202           }
2203         }
2204       }
2205 
2206       // Set async. pending exception in thread.
2207       set_pending_async_exception(java_throwable);
2208 
2209       if (TraceExceptions) {
2210        ResourceMark rm;
2211        tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2212       }
2213       // for AbortVMOnException flag
2214       NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2215     }
2216   }
2217 
2218 
2219   // Interrupt thread so it will wake up from a potential wait()
2220   Thread::interrupt(this);
2221 }
2222 
2223 // External suspension mechanism.
2224 //
2225 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2226 // to any VM_locks and it is at a transition
2227 // Self-suspension will happen on the transition out of the vm.
2228 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2229 //
2230 // Guarantees on return:
2231 //   + Target thread will not execute any new bytecode (that's why we need to
2232 //     force a safepoint)
2233 //   + Target thread will not enter any new monitors
2234 //
2235 void JavaThread::java_suspend() {
2236   { MutexLocker mu(Threads_lock);
2237     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2238        return;
2239     }
2240   }
2241 
2242   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2243     if (!is_external_suspend()) {
2244       // a racing resume has cancelled us; bail out now
2245       return;
2246     }
2247 
2248     // suspend is done
2249     uint32_t debug_bits = 0;
2250     // Warning: is_ext_suspend_completed() may temporarily drop the
2251     // SR_lock to allow the thread to reach a stable thread state if
2252     // it is currently in a transient thread state.
2253     if (is_ext_suspend_completed(false /* !called_by_wait */,
2254                                  SuspendRetryDelay, &debug_bits) ) {
2255       return;
2256     }
2257   }
2258 
2259   VM_ForceSafepoint vm_suspend;
2260   VMThread::execute(&vm_suspend);
2261 }
2262 
2263 // Part II of external suspension.
2264 // A JavaThread self suspends when it detects a pending external suspend
2265 // request. This is usually on transitions. It is also done in places
2266 // where continuing to the next transition would surprise the caller,
2267 // e.g., monitor entry.
2268 //
2269 // Returns the number of times that the thread self-suspended.
2270 //
2271 // Note: DO NOT call java_suspend_self() when you just want to block current
2272 //       thread. java_suspend_self() is the second stage of cooperative
2273 //       suspension for external suspend requests and should only be used
2274 //       to complete an external suspend request.
2275 //
2276 int JavaThread::java_suspend_self() {
2277   int ret = 0;
2278 
2279   // we are in the process of exiting so don't suspend
2280   if (is_exiting()) {
2281      clear_external_suspend();
2282      return ret;
2283   }
2284 
2285   assert(_anchor.walkable() ||
2286     (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2287     "must have walkable stack");
2288 
2289   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2290 
2291   assert(!this->is_ext_suspended(),
2292     "a thread trying to self-suspend should not already be suspended");
2293 
2294   if (this->is_suspend_equivalent()) {
2295     // If we are self-suspending as a result of the lifting of a
2296     // suspend equivalent condition, then the suspend_equivalent
2297     // flag is not cleared until we set the ext_suspended flag so
2298     // that wait_for_ext_suspend_completion() returns consistent
2299     // results.
2300     this->clear_suspend_equivalent();
2301   }
2302 
2303   // A racing resume may have cancelled us before we grabbed SR_lock
2304   // above. Or another external suspend request could be waiting for us
2305   // by the time we return from SR_lock()->wait(). The thread
2306   // that requested the suspension may already be trying to walk our
2307   // stack and if we return now, we can change the stack out from under
2308   // it. This would be a "bad thing (TM)" and cause the stack walker
2309   // to crash. We stay self-suspended until there are no more pending
2310   // external suspend requests.
2311   while (is_external_suspend()) {
2312     ret++;
2313     this->set_ext_suspended();
2314 
2315     // _ext_suspended flag is cleared by java_resume()
2316     while (is_ext_suspended()) {
2317       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2318     }
2319   }
2320 
2321   return ret;
2322 }
2323 
2324 #ifdef ASSERT
2325 // verify the JavaThread has not yet been published in the Threads::list, and
2326 // hence doesn't need protection from concurrent access at this stage
2327 void JavaThread::verify_not_published() {
2328   if (!Threads_lock->owned_by_self()) {
2329    MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
2330    assert( !Threads::includes(this),
2331            "java thread shouldn't have been published yet!");
2332   }
2333   else {
2334    assert( !Threads::includes(this),
2335            "java thread shouldn't have been published yet!");
2336   }
2337 }
2338 #endif
2339 
2340 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2341 // progress or when _suspend_flags is non-zero.
2342 // Current thread needs to self-suspend if there is a suspend request and/or
2343 // block if a safepoint is in progress.
2344 // Async exception ISN'T checked.
2345 // Note only the ThreadInVMfromNative transition can call this function
2346 // directly and when thread state is _thread_in_native_trans
2347 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2348   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2349 
2350   JavaThread *curJT = JavaThread::current();
2351   bool do_self_suspend = thread->is_external_suspend();
2352 
2353   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2354 
2355   // If JNIEnv proxies are allowed, don't self-suspend if the target
2356   // thread is not the current thread. In older versions of jdbx, jdbx
2357   // threads could call into the VM with another thread's JNIEnv so we
2358   // can be here operating on behalf of a suspended thread (4432884).
2359   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2360     JavaThreadState state = thread->thread_state();
2361 
2362     // We mark this thread_blocked state as a suspend-equivalent so
2363     // that a caller to is_ext_suspend_completed() won't be confused.
2364     // The suspend-equivalent state is cleared by java_suspend_self().
2365     thread->set_suspend_equivalent();
2366 
2367     // If the safepoint code sees the _thread_in_native_trans state, it will
2368     // wait until the thread changes to other thread state. There is no
2369     // guarantee on how soon we can obtain the SR_lock and complete the
2370     // self-suspend request. It would be a bad idea to let safepoint wait for
2371     // too long. Temporarily change the state to _thread_blocked to
2372     // let the VM thread know that this thread is ready for GC. The problem
2373     // of changing thread state is that safepoint could happen just after
2374     // java_suspend_self() returns after being resumed, and VM thread will
2375     // see the _thread_blocked state. We must check for safepoint
2376     // after restoring the state and make sure we won't leave while a safepoint
2377     // is in progress.
2378     thread->set_thread_state(_thread_blocked);
2379     thread->java_suspend_self();
2380     thread->set_thread_state(state);
2381     // Make sure new state is seen by VM thread
2382     if (os::is_MP()) {
2383       if (UseMembar) {
2384         // Force a fence between the write above and read below
2385         OrderAccess::fence();
2386       } else {
2387         // Must use this rather than serialization page in particular on Windows
2388         InterfaceSupport::serialize_memory(thread);
2389       }
2390     }
2391   }
2392 
2393   if (SafepointSynchronize::do_call_back()) {
2394     // If we are safepointing, then block the caller which may not be
2395     // the same as the target thread (see above).
2396     SafepointSynchronize::block(curJT);
2397   }
2398 
2399   if (thread->is_deopt_suspend()) {
2400     thread->clear_deopt_suspend();
2401     RegisterMap map(thread, false);
2402     frame f = thread->last_frame();
2403     while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2404       f = f.sender(&map);
2405     }
2406     if (f.id() == thread->must_deopt_id()) {
2407       thread->clear_must_deopt_id();
2408       f.deoptimize(thread);
2409     } else {
2410       fatal("missed deoptimization!");
2411     }
2412   }
2413 }
2414 
2415 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2416 // progress or when _suspend_flags is non-zero.
2417 // Current thread needs to self-suspend if there is a suspend request and/or
2418 // block if a safepoint is in progress.
2419 // Also check for pending async exception (not including unsafe access error).
2420 // Note only the native==>VM/Java barriers can call this function and when
2421 // thread state is _thread_in_native_trans.
2422 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2423   check_safepoint_and_suspend_for_native_trans(thread);
2424 
2425   if (thread->has_async_exception()) {
2426     // We are in _thread_in_native_trans state, don't handle unsafe
2427     // access error since that may block.
2428     thread->check_and_handle_async_exceptions(false);
2429   }
2430 }
2431 
2432 // This is a variant of the normal
2433 // check_special_condition_for_native_trans with slightly different
2434 // semantics for use by critical native wrappers.  It does all the
2435 // normal checks but also performs the transition back into
2436 // thread_in_Java state.  This is required so that critical natives
2437 // can potentially block and perform a GC if they are the last thread
2438 // exiting the GC_locker.
2439 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2440   check_special_condition_for_native_trans(thread);
2441 
2442   // Finish the transition
2443   thread->set_thread_state(_thread_in_Java);
2444 
2445   if (thread->do_critical_native_unlock()) {
2446     ThreadInVMfromJavaNoAsyncException tiv(thread);
2447     GC_locker::unlock_critical(thread);
2448     thread->clear_critical_native_unlock();
2449   }
2450 }
2451 
2452 // We need to guarantee the Threads_lock here, since resumes are not
2453 // allowed during safepoint synchronization
2454 // Can only resume from an external suspension
2455 void JavaThread::java_resume() {
2456   assert_locked_or_safepoint(Threads_lock);
2457 
2458   // Sanity check: thread is gone, has started exiting or the thread
2459   // was not externally suspended.
2460   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2461     return;
2462   }
2463 
2464   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2465 
2466   clear_external_suspend();
2467 
2468   if (is_ext_suspended()) {
2469     clear_ext_suspended();
2470     SR_lock()->notify_all();
2471   }
2472 }
2473 
2474 void JavaThread::create_stack_guard_pages() {
2475   if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2476   address low_addr = stack_base() - stack_size();
2477   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2478 
2479   int allocate = os::allocate_stack_guard_pages();
2480   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2481 
2482   if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2483     warning("Attempt to allocate stack guard pages failed.");
2484     return;
2485   }
2486 
2487   if (os::guard_memory((char *) low_addr, len)) {
2488     _stack_guard_state = stack_guard_enabled;
2489   } else {
2490     warning("Attempt to protect stack guard pages failed.");
2491     if (os::uncommit_memory((char *) low_addr, len)) {
2492       warning("Attempt to deallocate stack guard pages failed.");
2493     }
2494   }
2495 }
2496 
2497 void JavaThread::remove_stack_guard_pages() {
2498   assert(Thread::current() == this, "from different thread");
2499   if (_stack_guard_state == stack_guard_unused) return;
2500   address low_addr = stack_base() - stack_size();
2501   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2502 
2503   if (os::allocate_stack_guard_pages()) {
2504     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2505       _stack_guard_state = stack_guard_unused;
2506     } else {
2507       warning("Attempt to deallocate stack guard pages failed.");
2508     }
2509   } else {
2510     if (_stack_guard_state == stack_guard_unused) return;
2511     if (os::unguard_memory((char *) low_addr, len)) {
2512       _stack_guard_state = stack_guard_unused;
2513     } else {
2514         warning("Attempt to unprotect stack guard pages failed.");
2515     }
2516   }
2517 }
2518 
2519 void JavaThread::enable_stack_yellow_zone() {
2520   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2521   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2522 
2523   // The base notation is from the stacks point of view, growing downward.
2524   // We need to adjust it to work correctly with guard_memory()
2525   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2526 
2527   guarantee(base < stack_base(),"Error calculating stack yellow zone");
2528   guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2529 
2530   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2531     _stack_guard_state = stack_guard_enabled;
2532   } else {
2533     warning("Attempt to guard stack yellow zone failed.");
2534   }
2535   enable_register_stack_guard();
2536 }
2537 
2538 void JavaThread::disable_stack_yellow_zone() {
2539   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2540   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2541 
2542   // Simply return if called for a thread that does not use guard pages.
2543   if (_stack_guard_state == stack_guard_unused) return;
2544 
2545   // The base notation is from the stacks point of view, growing downward.
2546   // We need to adjust it to work correctly with guard_memory()
2547   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2548 
2549   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2550     _stack_guard_state = stack_guard_yellow_disabled;
2551   } else {
2552     warning("Attempt to unguard stack yellow zone failed.");
2553   }
2554   disable_register_stack_guard();
2555 }
2556 
2557 void JavaThread::enable_stack_red_zone() {
2558   // The base notation is from the stacks point of view, growing downward.
2559   // We need to adjust it to work correctly with guard_memory()
2560   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2561   address base = stack_red_zone_base() - stack_red_zone_size();
2562 
2563   guarantee(base < stack_base(),"Error calculating stack red zone");
2564   guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2565 
2566   if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2567     warning("Attempt to guard stack red zone failed.");
2568   }
2569 }
2570 
2571 void JavaThread::disable_stack_red_zone() {
2572   // The base notation is from the stacks point of view, growing downward.
2573   // We need to adjust it to work correctly with guard_memory()
2574   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2575   address base = stack_red_zone_base() - stack_red_zone_size();
2576   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2577     warning("Attempt to unguard stack red zone failed.");
2578   }
2579 }
2580 
2581 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2582   // ignore is there is no stack
2583   if (!has_last_Java_frame()) return;
2584   // traverse the stack frames. Starts from top frame.
2585   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2586     frame* fr = fst.current();
2587     f(fr, fst.register_map());
2588   }
2589 }
2590 
2591 
2592 #ifndef PRODUCT
2593 // Deoptimization
2594 // Function for testing deoptimization
2595 void JavaThread::deoptimize() {
2596   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2597   StackFrameStream fst(this, UseBiasedLocking);
2598   bool deopt = false;           // Dump stack only if a deopt actually happens.
2599   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2600   // Iterate over all frames in the thread and deoptimize
2601   for(; !fst.is_done(); fst.next()) {
2602     if(fst.current()->can_be_deoptimized()) {
2603 
2604       if (only_at) {
2605         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2606         // consists of comma or carriage return separated numbers so
2607         // search for the current bci in that string.
2608         address pc = fst.current()->pc();
2609         nmethod* nm =  (nmethod*) fst.current()->cb();
2610         ScopeDesc* sd = nm->scope_desc_at( pc);
2611         char buffer[8];
2612         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2613         size_t len = strlen(buffer);
2614         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2615         while (found != NULL) {
2616           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2617               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2618             // Check that the bci found is bracketed by terminators.
2619             break;
2620           }
2621           found = strstr(found + 1, buffer);
2622         }
2623         if (!found) {
2624           continue;
2625         }
2626       }
2627 
2628       if (DebugDeoptimization && !deopt) {
2629         deopt = true; // One-time only print before deopt
2630         tty->print_cr("[BEFORE Deoptimization]");
2631         trace_frames();
2632         trace_stack();
2633       }
2634       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2635     }
2636   }
2637 
2638   if (DebugDeoptimization && deopt) {
2639     tty->print_cr("[AFTER Deoptimization]");
2640     trace_frames();
2641   }
2642 }
2643 
2644 
2645 // Make zombies
2646 void JavaThread::make_zombies() {
2647   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2648     if (fst.current()->can_be_deoptimized()) {
2649       // it is a Java nmethod
2650       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2651       nm->make_not_entrant();
2652     }
2653   }
2654 }
2655 #endif // PRODUCT
2656 
2657 
2658 void JavaThread::deoptimized_wrt_marked_nmethods() {
2659   if (!has_last_Java_frame()) return;
2660   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2661   StackFrameStream fst(this, UseBiasedLocking);
2662   for(; !fst.is_done(); fst.next()) {
2663     if (fst.current()->should_be_deoptimized()) {
2664       if (LogCompilation && xtty != NULL) {
2665         nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2666         xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2667                    this->name(), nm != NULL ? nm->compile_id() : -1);
2668       }
2669 
2670       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2671     }
2672   }
2673 }
2674 
2675 
2676 // GC support
2677 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2678 
2679 void JavaThread::gc_epilogue() {
2680   frames_do(frame_gc_epilogue);
2681 }
2682 
2683 
2684 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2685 
2686 void JavaThread::gc_prologue() {
2687   frames_do(frame_gc_prologue);
2688 }
2689 
2690 // If the caller is a NamedThread, then remember, in the current scope,
2691 // the given JavaThread in its _processed_thread field.
2692 class RememberProcessedThread: public StackObj {
2693   NamedThread* _cur_thr;
2694 public:
2695   RememberProcessedThread(JavaThread* jthr) {
2696     Thread* thread = Thread::current();
2697     if (thread->is_Named_thread()) {
2698       _cur_thr = (NamedThread *)thread;
2699       _cur_thr->set_processed_thread(jthr);
2700     } else {
2701       _cur_thr = NULL;
2702     }
2703   }
2704 
2705   ~RememberProcessedThread() {
2706     if (_cur_thr) {
2707       _cur_thr->set_processed_thread(NULL);
2708     }
2709   }
2710 };
2711 
2712 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2713   // Verify that the deferred card marks have been flushed.
2714   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2715 
2716   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2717   // since there may be more than one thread using each ThreadProfiler.
2718 
2719   // Traverse the GCHandles
2720   Thread::oops_do(f, cld_f, cf);
2721 
2722   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2723           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2724 
2725   if (has_last_Java_frame()) {
2726     // Record JavaThread to GC thread
2727     RememberProcessedThread rpt(this);
2728 
2729     // Traverse the privileged stack
2730     if (_privileged_stack_top != NULL) {
2731       _privileged_stack_top->oops_do(f);
2732     }
2733 
2734     // traverse the registered growable array
2735     if (_array_for_gc != NULL) {
2736       for (int index = 0; index < _array_for_gc->length(); index++) {
2737         f->do_oop(_array_for_gc->adr_at(index));
2738       }
2739     }
2740 
2741     // Traverse the monitor chunks
2742     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2743       chunk->oops_do(f);
2744     }
2745 
2746     // Traverse the execution stack
2747     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2748       fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2749     }
2750   }
2751 
2752   // callee_target is never live across a gc point so NULL it here should
2753   // it still contain a methdOop.
2754 
2755   set_callee_target(NULL);
2756 
2757   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2758   // If we have deferred set_locals there might be oops waiting to be
2759   // written
2760   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2761   if (list != NULL) {
2762     for (int i = 0; i < list->length(); i++) {
2763       list->at(i)->oops_do(f);
2764     }
2765   }
2766 
2767   // Traverse instance variables at the end since the GC may be moving things
2768   // around using this function
2769   f->do_oop((oop*) &_threadObj);
2770   f->do_oop((oop*) &_vm_result);
2771   f->do_oop((oop*) &_exception_oop);
2772   f->do_oop((oop*) &_pending_async_exception);
2773 
2774   if (jvmti_thread_state() != NULL) {
2775     jvmti_thread_state()->oops_do(f);
2776   }
2777 }
2778 
2779 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2780   Thread::nmethods_do(cf);  // (super method is a no-op)
2781 
2782   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2783           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2784 
2785   if (has_last_Java_frame()) {
2786     // Traverse the execution stack
2787     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2788       fst.current()->nmethods_do(cf);
2789     }
2790   }
2791 }
2792 
2793 void JavaThread::metadata_do(void f(Metadata*)) {
2794   Thread::metadata_do(f);
2795   if (has_last_Java_frame()) {
2796     // Traverse the execution stack to call f() on the methods in the stack
2797     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2798       fst.current()->metadata_do(f);
2799     }
2800   } else if (is_Compiler_thread()) {
2801     // need to walk ciMetadata in current compile tasks to keep alive.
2802     CompilerThread* ct = (CompilerThread*)this;
2803     if (ct->env() != NULL) {
2804       ct->env()->metadata_do(f);
2805     }
2806   }
2807 }
2808 
2809 // Printing
2810 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2811   switch (_thread_state) {
2812   case _thread_uninitialized:     return "_thread_uninitialized";
2813   case _thread_new:               return "_thread_new";
2814   case _thread_new_trans:         return "_thread_new_trans";
2815   case _thread_in_native:         return "_thread_in_native";
2816   case _thread_in_native_trans:   return "_thread_in_native_trans";
2817   case _thread_in_vm:             return "_thread_in_vm";
2818   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2819   case _thread_in_Java:           return "_thread_in_Java";
2820   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2821   case _thread_blocked:           return "_thread_blocked";
2822   case _thread_blocked_trans:     return "_thread_blocked_trans";
2823   default:                        return "unknown thread state";
2824   }
2825 }
2826 
2827 #ifndef PRODUCT
2828 void JavaThread::print_thread_state_on(outputStream *st) const {
2829   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2830 };
2831 void JavaThread::print_thread_state() const {
2832   print_thread_state_on(tty);
2833 };
2834 #endif // PRODUCT
2835 
2836 // Called by Threads::print() for VM_PrintThreads operation
2837 void JavaThread::print_on(outputStream *st) const {
2838   st->print("\"%s\" ", get_thread_name());
2839   oop thread_oop = threadObj();
2840   if (thread_oop != NULL) {
2841     st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2842     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2843     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2844   }
2845   Thread::print_on(st);
2846   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2847   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2848   if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2849     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2850   }
2851 #ifndef PRODUCT
2852   print_thread_state_on(st);
2853   _safepoint_state->print_on(st);
2854 #endif // PRODUCT
2855 }
2856 
2857 // Called by fatal error handler. The difference between this and
2858 // JavaThread::print() is that we can't grab lock or allocate memory.
2859 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2860   st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
2861   oop thread_obj = threadObj();
2862   if (thread_obj != NULL) {
2863      if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2864   }
2865   st->print(" [");
2866   st->print("%s", _get_thread_state_name(_thread_state));
2867   if (osthread()) {
2868     st->print(", id=%d", osthread()->thread_id());
2869   }
2870   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2871             _stack_base - _stack_size, _stack_base);
2872   st->print("]");
2873   return;
2874 }
2875 
2876 // Verification
2877 
2878 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2879 
2880 void JavaThread::verify() {
2881   // Verify oops in the thread.
2882   oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2883 
2884   // Verify the stack frames.
2885   frames_do(frame_verify);
2886 }
2887 
2888 // CR 6300358 (sub-CR 2137150)
2889 // Most callers of this method assume that it can't return NULL but a
2890 // thread may not have a name whilst it is in the process of attaching to
2891 // the VM - see CR 6412693, and there are places where a JavaThread can be
2892 // seen prior to having it's threadObj set (eg JNI attaching threads and
2893 // if vm exit occurs during initialization). These cases can all be accounted
2894 // for such that this method never returns NULL.
2895 const char* JavaThread::get_thread_name() const {
2896 #ifdef ASSERT
2897   // early safepoints can hit while current thread does not yet have TLS
2898   if (!SafepointSynchronize::is_at_safepoint()) {
2899     Thread *cur = Thread::current();
2900     if (!(cur->is_Java_thread() && cur == this)) {
2901       // Current JavaThreads are allowed to get their own name without
2902       // the Threads_lock.
2903       assert_locked_or_safepoint(Threads_lock);
2904     }
2905   }
2906 #endif // ASSERT
2907     return get_thread_name_string();
2908 }
2909 
2910 // Returns a non-NULL representation of this thread's name, or a suitable
2911 // descriptive string if there is no set name
2912 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2913   const char* name_str;
2914   oop thread_obj = threadObj();
2915   if (thread_obj != NULL) {
2916     typeArrayOop name = java_lang_Thread::name(thread_obj);
2917     if (name != NULL) {
2918       if (buf == NULL) {
2919         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2920       }
2921       else {
2922         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2923       }
2924     }
2925     else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2926       name_str = "<no-name - thread is attaching>";
2927     }
2928     else {
2929       name_str = Thread::name();
2930     }
2931   }
2932   else {
2933     name_str = Thread::name();
2934   }
2935   assert(name_str != NULL, "unexpected NULL thread name");
2936   return name_str;
2937 }
2938 
2939 
2940 const char* JavaThread::get_threadgroup_name() const {
2941   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2942   oop thread_obj = threadObj();
2943   if (thread_obj != NULL) {
2944     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2945     if (thread_group != NULL) {
2946       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2947       // ThreadGroup.name can be null
2948       if (name != NULL) {
2949         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2950         return str;
2951       }
2952     }
2953   }
2954   return NULL;
2955 }
2956 
2957 const char* JavaThread::get_parent_name() const {
2958   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2959   oop thread_obj = threadObj();
2960   if (thread_obj != NULL) {
2961     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2962     if (thread_group != NULL) {
2963       oop parent = java_lang_ThreadGroup::parent(thread_group);
2964       if (parent != NULL) {
2965         typeArrayOop name = java_lang_ThreadGroup::name(parent);
2966         // ThreadGroup.name can be null
2967         if (name != NULL) {
2968           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2969           return str;
2970         }
2971       }
2972     }
2973   }
2974   return NULL;
2975 }
2976 
2977 ThreadPriority JavaThread::java_priority() const {
2978   oop thr_oop = threadObj();
2979   if (thr_oop == NULL) return NormPriority; // Bootstrapping
2980   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2981   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2982   return priority;
2983 }
2984 
2985 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2986 
2987   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2988   // Link Java Thread object <-> C++ Thread
2989 
2990   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2991   // and put it into a new Handle.  The Handle "thread_oop" can then
2992   // be used to pass the C++ thread object to other methods.
2993 
2994   // Set the Java level thread object (jthread) field of the
2995   // new thread (a JavaThread *) to C++ thread object using the
2996   // "thread_oop" handle.
2997 
2998   // Set the thread field (a JavaThread *) of the
2999   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3000 
3001   Handle thread_oop(Thread::current(),
3002                     JNIHandles::resolve_non_null(jni_thread));
3003   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3004     "must be initialized");
3005   set_threadObj(thread_oop());
3006   java_lang_Thread::set_thread(thread_oop(), this);
3007 
3008   if (prio == NoPriority) {
3009     prio = java_lang_Thread::priority(thread_oop());
3010     assert(prio != NoPriority, "A valid priority should be present");
3011   }
3012 
3013   // Push the Java priority down to the native thread; needs Threads_lock
3014   Thread::set_priority(this, prio);
3015 
3016   // Add the new thread to the Threads list and set it in motion.
3017   // We must have threads lock in order to call Threads::add.
3018   // It is crucial that we do not block before the thread is
3019   // added to the Threads list for if a GC happens, then the java_thread oop
3020   // will not be visited by GC.
3021   Threads::add(this);
3022 }
3023 
3024 oop JavaThread::current_park_blocker() {
3025   // Support for JSR-166 locks
3026   oop thread_oop = threadObj();
3027   if (thread_oop != NULL &&
3028       JDK_Version::current().supports_thread_park_blocker()) {
3029     return java_lang_Thread::park_blocker(thread_oop);
3030   }
3031   return NULL;
3032 }
3033 
3034 
3035 void JavaThread::print_stack_on(outputStream* st) {
3036   if (!has_last_Java_frame()) return;
3037   ResourceMark rm;
3038   HandleMark   hm;
3039 
3040   RegisterMap reg_map(this);
3041   vframe* start_vf = last_java_vframe(&reg_map);
3042   int count = 0;
3043   for (vframe* f = start_vf; f; f = f->sender() ) {
3044     if (f->is_java_frame()) {
3045       javaVFrame* jvf = javaVFrame::cast(f);
3046       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3047 
3048       // Print out lock information
3049       if (JavaMonitorsInStackTrace) {
3050         jvf->print_lock_info_on(st, count);
3051       }
3052     } else {
3053       // Ignore non-Java frames
3054     }
3055 
3056     // Bail-out case for too deep stacks
3057     count++;
3058     if (MaxJavaStackTraceDepth == count) return;
3059   }
3060 }
3061 
3062 
3063 // JVMTI PopFrame support
3064 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3065   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3066   if (in_bytes(size_in_bytes) != 0) {
3067     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3068     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3069     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3070   }
3071 }
3072 
3073 void* JavaThread::popframe_preserved_args() {
3074   return _popframe_preserved_args;
3075 }
3076 
3077 ByteSize JavaThread::popframe_preserved_args_size() {
3078   return in_ByteSize(_popframe_preserved_args_size);
3079 }
3080 
3081 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3082   int sz = in_bytes(popframe_preserved_args_size());
3083   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3084   return in_WordSize(sz / wordSize);
3085 }
3086 
3087 void JavaThread::popframe_free_preserved_args() {
3088   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3089   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3090   _popframe_preserved_args = NULL;
3091   _popframe_preserved_args_size = 0;
3092 }
3093 
3094 #ifndef PRODUCT
3095 
3096 void JavaThread::trace_frames() {
3097   tty->print_cr("[Describe stack]");
3098   int frame_no = 1;
3099   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3100     tty->print("  %d. ", frame_no++);
3101     fst.current()->print_value_on(tty,this);
3102     tty->cr();
3103   }
3104 }
3105 
3106 class PrintAndVerifyOopClosure: public OopClosure {
3107  protected:
3108   template <class T> inline void do_oop_work(T* p) {
3109     oop obj = oopDesc::load_decode_heap_oop(p);
3110     if (obj == NULL) return;
3111     tty->print(INTPTR_FORMAT ": ", p);
3112     if (obj->is_oop_or_null()) {
3113       if (obj->is_objArray()) {
3114         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3115       } else {
3116         obj->print();
3117       }
3118     } else {
3119       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3120     }
3121     tty->cr();
3122   }
3123  public:
3124   virtual void do_oop(oop* p) { do_oop_work(p); }
3125   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3126 };
3127 
3128 
3129 static void oops_print(frame* f, const RegisterMap *map) {
3130   PrintAndVerifyOopClosure print;
3131   f->print_value();
3132   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3133 }
3134 
3135 // Print our all the locations that contain oops and whether they are
3136 // valid or not.  This useful when trying to find the oldest frame
3137 // where an oop has gone bad since the frame walk is from youngest to
3138 // oldest.
3139 void JavaThread::trace_oops() {
3140   tty->print_cr("[Trace oops]");
3141   frames_do(oops_print);
3142 }
3143 
3144 
3145 #ifdef ASSERT
3146 // Print or validate the layout of stack frames
3147 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3148   ResourceMark rm;
3149   PRESERVE_EXCEPTION_MARK;
3150   FrameValues values;
3151   int frame_no = 0;
3152   for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3153     fst.current()->describe(values, ++frame_no);
3154     if (depth == frame_no) break;
3155   }
3156   if (validate_only) {
3157     values.validate();
3158   } else {
3159     tty->print_cr("[Describe stack layout]");
3160     values.print(this);
3161   }
3162 }
3163 #endif
3164 
3165 void JavaThread::trace_stack_from(vframe* start_vf) {
3166   ResourceMark rm;
3167   int vframe_no = 1;
3168   for (vframe* f = start_vf; f; f = f->sender() ) {
3169     if (f->is_java_frame()) {
3170       javaVFrame::cast(f)->print_activation(vframe_no++);
3171     } else {
3172       f->print();
3173     }
3174     if (vframe_no > StackPrintLimit) {
3175       tty->print_cr("...<more frames>...");
3176       return;
3177     }
3178   }
3179 }
3180 
3181 
3182 void JavaThread::trace_stack() {
3183   if (!has_last_Java_frame()) return;
3184   ResourceMark rm;
3185   HandleMark   hm;
3186   RegisterMap reg_map(this);
3187   trace_stack_from(last_java_vframe(&reg_map));
3188 }
3189 
3190 
3191 #endif // PRODUCT
3192 
3193 
3194 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3195   assert(reg_map != NULL, "a map must be given");
3196   frame f = last_frame();
3197   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3198     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3199   }
3200   return NULL;
3201 }
3202 
3203 
3204 Klass* JavaThread::security_get_caller_class(int depth) {
3205   vframeStream vfst(this);
3206   vfst.security_get_caller_frame(depth);
3207   if (!vfst.at_end()) {
3208     return vfst.method()->method_holder();
3209   }
3210   return NULL;
3211 }
3212 
3213 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3214   assert(thread->is_Compiler_thread(), "must be compiler thread");
3215   CompileBroker::compiler_thread_loop();
3216 }
3217 
3218 // Create a CompilerThread
3219 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3220 : JavaThread(&compiler_thread_entry) {
3221   _env   = NULL;
3222   _log   = NULL;
3223   _task  = NULL;
3224   _queue = queue;
3225   _counters = counters;
3226   _buffer_blob = NULL;
3227   _scanned_nmethod = NULL;
3228 
3229 #ifndef PRODUCT
3230   _ideal_graph_printer = NULL;
3231 #endif
3232 }
3233 
3234 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3235   JavaThread::oops_do(f, cld_f, cf);
3236   if (_scanned_nmethod != NULL && cf != NULL) {
3237     // Safepoints can occur when the sweeper is scanning an nmethod so
3238     // process it here to make sure it isn't unloaded in the middle of
3239     // a scan.
3240     cf->do_code_blob(_scanned_nmethod);
3241   }
3242 }
3243 
3244 // ======= Threads ========
3245 
3246 // The Threads class links together all active threads, and provides
3247 // operations over all threads.  It is protected by its own Mutex
3248 // lock, which is also used in other contexts to protect thread
3249 // operations from having the thread being operated on from exiting
3250 // and going away unexpectedly (e.g., safepoint synchronization)
3251 
3252 JavaThread* Threads::_thread_list = NULL;
3253 int         Threads::_number_of_threads = 0;
3254 int         Threads::_number_of_non_daemon_threads = 0;
3255 int         Threads::_return_code = 0;
3256 size_t      JavaThread::_stack_size_at_create = 0;
3257 #ifdef ASSERT
3258 bool        Threads::_vm_complete = false;
3259 #endif
3260 
3261 // All JavaThreads
3262 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3263 
3264 void os_stream();
3265 
3266 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3267 void Threads::threads_do(ThreadClosure* tc) {
3268   assert_locked_or_safepoint(Threads_lock);
3269   // ALL_JAVA_THREADS iterates through all JavaThreads
3270   ALL_JAVA_THREADS(p) {
3271     tc->do_thread(p);
3272   }
3273   // Someday we could have a table or list of all non-JavaThreads.
3274   // For now, just manually iterate through them.
3275   tc->do_thread(VMThread::vm_thread());
3276   Universe::heap()->gc_threads_do(tc);
3277   WatcherThread *wt = WatcherThread::watcher_thread();
3278   // Strictly speaking, the following NULL check isn't sufficient to make sure
3279   // the data for WatcherThread is still valid upon being examined. However,
3280   // considering that WatchThread terminates when the VM is on the way to
3281   // exit at safepoint, the chance of the above is extremely small. The right
3282   // way to prevent termination of WatcherThread would be to acquire
3283   // Terminator_lock, but we can't do that without violating the lock rank
3284   // checking in some cases.
3285   if (wt != NULL)
3286     tc->do_thread(wt);
3287 
3288   // If CompilerThreads ever become non-JavaThreads, add them here
3289 }
3290 
3291 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3292 
3293   extern void JDK_Version_init();
3294 
3295   // Check version
3296   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3297 
3298   // Initialize the output stream module
3299   ostream_init();
3300 
3301   // Process java launcher properties.
3302   Arguments::process_sun_java_launcher_properties(args);
3303 
3304   // Initialize the os module before using TLS
3305   os::init();
3306 
3307   // Initialize system properties.
3308   Arguments::init_system_properties();
3309 
3310   // So that JDK version can be used as a discrimintor when parsing arguments
3311   JDK_Version_init();
3312 
3313   // Update/Initialize System properties after JDK version number is known
3314   Arguments::init_version_specific_system_properties();
3315 
3316   // Parse arguments
3317   jint parse_result = Arguments::parse(args);
3318   if (parse_result != JNI_OK) return parse_result;
3319 
3320   if (PauseAtStartup) {
3321     os::pause();
3322   }
3323 
3324 #ifndef USDT2
3325   HS_DTRACE_PROBE(hotspot, vm__init__begin);
3326 #else /* USDT2 */
3327   HOTSPOT_VM_INIT_BEGIN();
3328 #endif /* USDT2 */
3329 
3330   // Record VM creation timing statistics
3331   TraceVmCreationTime create_vm_timer;
3332   create_vm_timer.start();
3333 
3334   // Timing (must come after argument parsing)
3335   TraceTime timer("Create VM", TraceStartupTime);
3336 
3337   // Initialize the os module after parsing the args
3338   jint os_init_2_result = os::init_2();
3339   if (os_init_2_result != JNI_OK) return os_init_2_result;
3340 
3341   jint adjust_after_os_result = Arguments::adjust_after_os();
3342   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3343 
3344   // intialize TLS
3345   ThreadLocalStorage::init();
3346 
3347   // Bootstrap native memory tracking, so it can start recording memory
3348   // activities before worker thread is started. This is the first phase
3349   // of bootstrapping, VM is currently running in single-thread mode.
3350   MemTracker::bootstrap_single_thread();
3351 
3352   // Initialize output stream logging
3353   ostream_init_log();
3354 
3355   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3356   // Must be before create_vm_init_agents()
3357   if (Arguments::init_libraries_at_startup()) {
3358     convert_vm_init_libraries_to_agents();
3359   }
3360 
3361   // Launch -agentlib/-agentpath and converted -Xrun agents
3362   if (Arguments::init_agents_at_startup()) {
3363     create_vm_init_agents();
3364   }
3365 
3366   // Initialize Threads state
3367   _thread_list = NULL;
3368   _number_of_threads = 0;
3369   _number_of_non_daemon_threads = 0;
3370 
3371   // Initialize global data structures and create system classes in heap
3372   vm_init_globals();
3373 
3374   // Attach the main thread to this os thread
3375   JavaThread* main_thread = new JavaThread();
3376   main_thread->set_thread_state(_thread_in_vm);
3377   // must do this before set_active_handles and initialize_thread_local_storage
3378   // Note: on solaris initialize_thread_local_storage() will (indirectly)
3379   // change the stack size recorded here to one based on the java thread
3380   // stacksize. This adjusted size is what is used to figure the placement
3381   // of the guard pages.
3382   main_thread->record_stack_base_and_size();
3383   main_thread->initialize_thread_local_storage();
3384 
3385   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3386 
3387   if (!main_thread->set_as_starting_thread()) {
3388     vm_shutdown_during_initialization(
3389       "Failed necessary internal allocation. Out of swap space");
3390     delete main_thread;
3391     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3392     return JNI_ENOMEM;
3393   }
3394 
3395   // Enable guard page *after* os::create_main_thread(), otherwise it would
3396   // crash Linux VM, see notes in os_linux.cpp.
3397   main_thread->create_stack_guard_pages();
3398 
3399   // Initialize Java-Level synchronization subsystem
3400   ObjectMonitor::Initialize() ;
3401 
3402   // Second phase of bootstrapping, VM is about entering multi-thread mode
3403   MemTracker::bootstrap_multi_thread();
3404 
3405   // Initialize global modules
3406   jint status = init_globals();
3407   if (status != JNI_OK) {
3408     delete main_thread;
3409     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3410     return status;
3411   }
3412 
3413   // Should be done after the heap is fully created
3414   main_thread->cache_global_variables();
3415 
3416   HandleMark hm;
3417 
3418   { MutexLocker mu(Threads_lock);
3419     Threads::add(main_thread);
3420   }
3421 
3422   // Any JVMTI raw monitors entered in onload will transition into
3423   // real raw monitor. VM is setup enough here for raw monitor enter.
3424   JvmtiExport::transition_pending_onload_raw_monitors();
3425 
3426   if (VerifyBeforeGC &&
3427       Universe::heap()->total_collections() >= VerifyGCStartAt) {
3428     Universe::heap()->prepare_for_verify();
3429     Universe::verify();   // make sure we're starting with a clean slate
3430   }
3431 
3432   // Fully start NMT
3433   MemTracker::start();
3434 
3435   // Create the VMThread
3436   { TraceTime timer("Start VMThread", TraceStartupTime);
3437     VMThread::create();
3438     Thread* vmthread = VMThread::vm_thread();
3439 
3440     if (!os::create_thread(vmthread, os::vm_thread))
3441       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3442 
3443     // Wait for the VM thread to become ready, and VMThread::run to initialize
3444     // Monitors can have spurious returns, must always check another state flag
3445     {
3446       MutexLocker ml(Notify_lock);
3447       os::start_thread(vmthread);
3448       while (vmthread->active_handles() == NULL) {
3449         Notify_lock->wait();
3450       }
3451     }
3452   }
3453 
3454   assert (Universe::is_fully_initialized(), "not initialized");
3455   EXCEPTION_MARK;
3456 
3457   // At this point, the Universe is initialized, but we have not executed
3458   // any byte code.  Now is a good time (the only time) to dump out the
3459   // internal state of the JVM for sharing.
3460   if (DumpSharedSpaces) {
3461     MetaspaceShared::preload_and_dump(CHECK_0);
3462     ShouldNotReachHere();
3463   }
3464 
3465   // Always call even when there are not JVMTI environments yet, since environments
3466   // may be attached late and JVMTI must track phases of VM execution
3467   JvmtiExport::enter_start_phase();
3468 
3469   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3470   JvmtiExport::post_vm_start();
3471 
3472   {
3473     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3474 
3475     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3476       create_vm_init_libraries();
3477     }
3478 
3479     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3480 
3481     if (AggressiveOpts) {
3482       {
3483         // Forcibly initialize java/util/HashMap and mutate the private
3484         // static final "frontCacheEnabled" field before we start creating instances
3485 #ifdef ASSERT
3486         Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3487         assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3488 #endif
3489         Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3490         KlassHandle k = KlassHandle(THREAD, k_o);
3491         guarantee(k.not_null(), "Must find java/util/HashMap");
3492         instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3493         ik->initialize(CHECK_0);
3494         fieldDescriptor fd;
3495         // Possible we might not find this field; if so, don't break
3496         if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3497           k()->java_mirror()->bool_field_put(fd.offset(), true);
3498         }
3499       }
3500 
3501       if (UseStringCache) {
3502         // Forcibly initialize java/lang/StringValue and mutate the private
3503         // static final "stringCacheEnabled" field before we start creating instances
3504         Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3505         // Possible that StringValue isn't present: if so, silently don't break
3506         if (k_o != NULL) {
3507           KlassHandle k = KlassHandle(THREAD, k_o);
3508           instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3509           ik->initialize(CHECK_0);
3510           fieldDescriptor fd;
3511           // Possible we might not find this field: if so, silently don't break
3512           if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3513             k()->java_mirror()->bool_field_put(fd.offset(), true);
3514           }
3515         }
3516       }
3517     }
3518 
3519     // Initialize java_lang.System (needed before creating the thread)
3520     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3521     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3522     Handle thread_group = create_initial_thread_group(CHECK_0);
3523     Universe::set_main_thread_group(thread_group());
3524     initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3525     oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3526     main_thread->set_threadObj(thread_object);
3527     // Set thread status to running since main thread has
3528     // been started and running.
3529     java_lang_Thread::set_thread_status(thread_object,
3530                                         java_lang_Thread::RUNNABLE);
3531 
3532     // The VM creates & returns objects of this class. Make sure it's initialized.
3533     initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3534 
3535     // The VM preresolves methods to these classes. Make sure that they get initialized
3536     initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3537     initialize_class(vmSymbols::java_lang_ref_Finalizer(),  CHECK_0);
3538     call_initializeSystemClass(CHECK_0);
3539 
3540     // get the Java runtime name after java.lang.System is initialized
3541     JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3542     JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3543 
3544     // an instance of OutOfMemory exception has been allocated earlier
3545     initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3546     initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3547     initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3548     initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3549     initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3550     initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3551     initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3552     initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3553   }
3554 
3555   // See        : bugid 4211085.
3556   // Background : the static initializer of java.lang.Compiler tries to read
3557   //              property"java.compiler" and read & write property "java.vm.info".
3558   //              When a security manager is installed through the command line
3559   //              option "-Djava.security.manager", the above properties are not
3560   //              readable and the static initializer for java.lang.Compiler fails
3561   //              resulting in a NoClassDefFoundError.  This can happen in any
3562   //              user code which calls methods in java.lang.Compiler.
3563   // Hack :       the hack is to pre-load and initialize this class, so that only
3564   //              system domains are on the stack when the properties are read.
3565   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3566   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3567   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3568   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3569   //              Once that is done, we should remove this hack.
3570   initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3571 
3572   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3573   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3574   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3575   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3576   // This should also be taken out as soon as 4211383 gets fixed.
3577   reset_vm_info_property(CHECK_0);
3578 
3579   quicken_jni_functions();
3580 
3581   // Must be run after init_ft which initializes ft_enabled
3582   if (TRACE_INITIALIZE() != JNI_OK) {
3583     vm_exit_during_initialization("Failed to initialize tracing backend");
3584   }
3585 
3586   // Set flag that basic initialization has completed. Used by exceptions and various
3587   // debug stuff, that does not work until all basic classes have been initialized.
3588   set_init_completed();
3589 
3590 #ifndef USDT2
3591   HS_DTRACE_PROBE(hotspot, vm__init__end);
3592 #else /* USDT2 */
3593   HOTSPOT_VM_INIT_END();
3594 #endif /* USDT2 */
3595 
3596   // record VM initialization completion time
3597 #if INCLUDE_MANAGEMENT
3598   Management::record_vm_init_completed();
3599 #endif // INCLUDE_MANAGEMENT
3600 
3601   // Compute system loader. Note that this has to occur after set_init_completed, since
3602   // valid exceptions may be thrown in the process.
3603   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3604   // set_init_completed has just been called, causing exceptions not to be shortcut
3605   // anymore. We call vm_exit_during_initialization directly instead.
3606   SystemDictionary::compute_java_system_loader(THREAD);
3607   if (HAS_PENDING_EXCEPTION) {
3608     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3609   }
3610 
3611 #if INCLUDE_ALL_GCS
3612   // Support for ConcurrentMarkSweep. This should be cleaned up
3613   // and better encapsulated. The ugly nested if test would go away
3614   // once things are properly refactored. XXX YSR
3615   if (UseConcMarkSweepGC || UseG1GC) {
3616     if (UseConcMarkSweepGC) {
3617       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3618     } else {
3619       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3620     }
3621     if (HAS_PENDING_EXCEPTION) {
3622       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3623     }
3624   }
3625 #endif // INCLUDE_ALL_GCS
3626 
3627   // Always call even when there are not JVMTI environments yet, since environments
3628   // may be attached late and JVMTI must track phases of VM execution
3629   JvmtiExport::enter_live_phase();
3630 
3631   // Signal Dispatcher needs to be started before VMInit event is posted
3632   os::signal_init();
3633 
3634   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3635   if (!DisableAttachMechanism) {
3636     if (StartAttachListener || AttachListener::init_at_startup()) {
3637       AttachListener::init();
3638     }
3639   }
3640 
3641   // Launch -Xrun agents
3642   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3643   // back-end can launch with -Xdebug -Xrunjdwp.
3644   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3645     create_vm_init_libraries();
3646   }
3647 
3648   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3649   JvmtiExport::post_vm_initialized();
3650 
3651   if (!TRACE_START()) {
3652     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3653   }
3654 
3655   if (CleanChunkPoolAsync) {
3656     Chunk::start_chunk_pool_cleaner_task();
3657   }
3658 
3659   // initialize compiler(s)
3660 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3661   CompileBroker::compilation_init();
3662 #endif
3663 
3664 #if INCLUDE_MANAGEMENT
3665   Management::initialize(THREAD);
3666 #endif // INCLUDE_MANAGEMENT
3667 
3668   if (HAS_PENDING_EXCEPTION) {
3669     // management agent fails to start possibly due to
3670     // configuration problem and is responsible for printing
3671     // stack trace if appropriate. Simply exit VM.
3672     vm_exit(1);
3673   }
3674 
3675   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3676   if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3677   if (MemProfiling)                   MemProfiler::engage();
3678   StatSampler::engage();
3679   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3680 
3681   BiasedLocking::init();
3682 
3683   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3684     call_postVMInitHook(THREAD);
3685     // The Java side of PostVMInitHook.run must deal with all
3686     // exceptions and provide means of diagnosis.
3687     if (HAS_PENDING_EXCEPTION) {
3688       CLEAR_PENDING_EXCEPTION;
3689     }
3690   }
3691 
3692   {
3693       MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3694       // Make sure the watcher thread can be started by WatcherThread::start()
3695       // or by dynamic enrollment.
3696       WatcherThread::make_startable();
3697       // Start up the WatcherThread if there are any periodic tasks
3698       // NOTE:  All PeriodicTasks should be registered by now. If they
3699       //   aren't, late joiners might appear to start slowly (we might
3700       //   take a while to process their first tick).
3701       if (PeriodicTask::num_tasks() > 0) {
3702           WatcherThread::start();
3703       }
3704   }
3705 
3706   // Give os specific code one last chance to start
3707   os::init_3();
3708 
3709   create_vm_timer.end();
3710 #ifdef ASSERT
3711   _vm_complete = true;
3712 #endif
3713   return JNI_OK;
3714 }
3715 
3716 // type for the Agent_OnLoad and JVM_OnLoad entry points
3717 extern "C" {
3718   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3719 }
3720 // Find a command line agent library and return its entry point for
3721 //         -agentlib:  -agentpath:   -Xrun
3722 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3723 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3724   OnLoadEntry_t on_load_entry = NULL;
3725   void *library = agent->os_lib();  // check if we have looked it up before
3726 
3727   if (library == NULL) {
3728     char buffer[JVM_MAXPATHLEN];
3729     char ebuf[1024];
3730     const char *name = agent->name();
3731     const char *msg = "Could not find agent library ";
3732 
3733     if (agent->is_absolute_path()) {
3734       library = os::dll_load(name, ebuf, sizeof ebuf);
3735       if (library == NULL) {
3736         const char *sub_msg = " in absolute path, with error: ";
3737         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3738         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3739         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3740         // If we can't find the agent, exit.
3741         vm_exit_during_initialization(buf, NULL);
3742         FREE_C_HEAP_ARRAY(char, buf, mtThread);
3743       }
3744     } else {
3745       // Try to load the agent from the standard dll directory
3746       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3747                              name)) {
3748         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3749       }
3750       if (library == NULL) { // Try the local directory
3751         char ns[1] = {0};
3752         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3753           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3754         }
3755         if (library == NULL) {
3756           const char *sub_msg = " on the library path, with error: ";
3757           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3758           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3759           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3760           // If we can't find the agent, exit.
3761           vm_exit_during_initialization(buf, NULL);
3762           FREE_C_HEAP_ARRAY(char, buf, mtThread);
3763         }
3764       }
3765     }
3766     agent->set_os_lib(library);
3767   }
3768 
3769   // Find the OnLoad function.
3770   for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3771     on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3772     if (on_load_entry != NULL) break;
3773   }
3774   return on_load_entry;
3775 }
3776 
3777 // Find the JVM_OnLoad entry point
3778 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3779   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3780   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3781 }
3782 
3783 // Find the Agent_OnLoad entry point
3784 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3785   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3786   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3787 }
3788 
3789 // For backwards compatibility with -Xrun
3790 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3791 // treated like -agentpath:
3792 // Must be called before agent libraries are created
3793 void Threads::convert_vm_init_libraries_to_agents() {
3794   AgentLibrary* agent;
3795   AgentLibrary* next;
3796 
3797   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3798     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3799     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3800 
3801     // If there is an JVM_OnLoad function it will get called later,
3802     // otherwise see if there is an Agent_OnLoad
3803     if (on_load_entry == NULL) {
3804       on_load_entry = lookup_agent_on_load(agent);
3805       if (on_load_entry != NULL) {
3806         // switch it to the agent list -- so that Agent_OnLoad will be called,
3807         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3808         Arguments::convert_library_to_agent(agent);
3809       } else {
3810         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3811       }
3812     }
3813   }
3814 }
3815 
3816 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3817 // Invokes Agent_OnLoad
3818 // Called very early -- before JavaThreads exist
3819 void Threads::create_vm_init_agents() {
3820   extern struct JavaVM_ main_vm;
3821   AgentLibrary* agent;
3822 
3823   JvmtiExport::enter_onload_phase();
3824 
3825   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3826     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3827 
3828     if (on_load_entry != NULL) {
3829       // Invoke the Agent_OnLoad function
3830       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3831       if (err != JNI_OK) {
3832         vm_exit_during_initialization("agent library failed to init", agent->name());
3833       }
3834     } else {
3835       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3836     }
3837   }
3838   JvmtiExport::enter_primordial_phase();
3839 }
3840 
3841 extern "C" {
3842   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3843 }
3844 
3845 void Threads::shutdown_vm_agents() {
3846   // Send any Agent_OnUnload notifications
3847   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3848   extern struct JavaVM_ main_vm;
3849   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3850 
3851     // Find the Agent_OnUnload function.
3852     for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3853       Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3854                os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3855 
3856       // Invoke the Agent_OnUnload function
3857       if (unload_entry != NULL) {
3858         JavaThread* thread = JavaThread::current();
3859         ThreadToNativeFromVM ttn(thread);
3860         HandleMark hm(thread);
3861         (*unload_entry)(&main_vm);
3862         break;
3863       }
3864     }
3865   }
3866 }
3867 
3868 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3869 // Invokes JVM_OnLoad
3870 void Threads::create_vm_init_libraries() {
3871   extern struct JavaVM_ main_vm;
3872   AgentLibrary* agent;
3873 
3874   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3875     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3876 
3877     if (on_load_entry != NULL) {
3878       // Invoke the JVM_OnLoad function
3879       JavaThread* thread = JavaThread::current();
3880       ThreadToNativeFromVM ttn(thread);
3881       HandleMark hm(thread);
3882       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3883       if (err != JNI_OK) {
3884         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3885       }
3886     } else {
3887       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3888     }
3889   }
3890 }
3891 
3892 // Last thread running calls java.lang.Shutdown.shutdown()
3893 void JavaThread::invoke_shutdown_hooks() {
3894   HandleMark hm(this);
3895 
3896   // We could get here with a pending exception, if so clear it now.
3897   if (this->has_pending_exception()) {
3898     this->clear_pending_exception();
3899   }
3900 
3901   EXCEPTION_MARK;
3902   Klass* k =
3903     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3904                                       THREAD);
3905   if (k != NULL) {
3906     // SystemDictionary::resolve_or_null will return null if there was
3907     // an exception.  If we cannot load the Shutdown class, just don't
3908     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3909     // and finalizers (if runFinalizersOnExit is set) won't be run.
3910     // Note that if a shutdown hook was registered or runFinalizersOnExit
3911     // was called, the Shutdown class would have already been loaded
3912     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3913     instanceKlassHandle shutdown_klass (THREAD, k);
3914     JavaValue result(T_VOID);
3915     JavaCalls::call_static(&result,
3916                            shutdown_klass,
3917                            vmSymbols::shutdown_method_name(),
3918                            vmSymbols::void_method_signature(),
3919                            THREAD);
3920   }
3921   CLEAR_PENDING_EXCEPTION;
3922 }
3923 
3924 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3925 // the program falls off the end of main(). Another VM exit path is through
3926 // vm_exit() when the program calls System.exit() to return a value or when
3927 // there is a serious error in VM. The two shutdown paths are not exactly
3928 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3929 // and VM_Exit op at VM level.
3930 //
3931 // Shutdown sequence:
3932 //   + Shutdown native memory tracking if it is on
3933 //   + Wait until we are the last non-daemon thread to execute
3934 //     <-- every thing is still working at this moment -->
3935 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3936 //        shutdown hooks, run finalizers if finalization-on-exit
3937 //   + Call before_exit(), prepare for VM exit
3938 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3939 //        currently the only user of this mechanism is File.deleteOnExit())
3940 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3941 //        post thread end and vm death events to JVMTI,
3942 //        stop signal thread
3943 //   + Call JavaThread::exit(), it will:
3944 //      > release JNI handle blocks, remove stack guard pages
3945 //      > remove this thread from Threads list
3946 //     <-- no more Java code from this thread after this point -->
3947 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3948 //     the compiler threads at safepoint
3949 //     <-- do not use anything that could get blocked by Safepoint -->
3950 //   + Disable tracing at JNI/JVM barriers
3951 //   + Set _vm_exited flag for threads that are still running native code
3952 //   + Delete this thread
3953 //   + Call exit_globals()
3954 //      > deletes tty
3955 //      > deletes PerfMemory resources
3956 //   + Return to caller
3957 
3958 bool Threads::destroy_vm() {
3959   JavaThread* thread = JavaThread::current();
3960 
3961 #ifdef ASSERT
3962   _vm_complete = false;
3963 #endif
3964   // Wait until we are the last non-daemon thread to execute
3965   { MutexLocker nu(Threads_lock);
3966     while (Threads::number_of_non_daemon_threads() > 1 )
3967       // This wait should make safepoint checks, wait without a timeout,
3968       // and wait as a suspend-equivalent condition.
3969       //
3970       // Note: If the FlatProfiler is running and this thread is waiting
3971       // for another non-daemon thread to finish, then the FlatProfiler
3972       // is waiting for the external suspend request on this thread to
3973       // complete. wait_for_ext_suspend_completion() will eventually
3974       // timeout, but that takes time. Making this wait a suspend-
3975       // equivalent condition solves that timeout problem.
3976       //
3977       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3978                          Mutex::_as_suspend_equivalent_flag);
3979   }
3980 
3981   // Hang forever on exit if we are reporting an error.
3982   if (ShowMessageBoxOnError && is_error_reported()) {
3983     os::infinite_sleep();
3984   }
3985   os::wait_for_keypress_at_exit();
3986 
3987   if (JDK_Version::is_jdk12x_version()) {
3988     // We are the last thread running, so check if finalizers should be run.
3989     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3990     HandleMark rm(thread);
3991     Universe::run_finalizers_on_exit();
3992   } else {
3993     // run Java level shutdown hooks
3994     thread->invoke_shutdown_hooks();
3995   }
3996 
3997   before_exit(thread);
3998 
3999   thread->exit(true);
4000 
4001   // Stop VM thread.
4002   {
4003     // 4945125 The vm thread comes to a safepoint during exit.
4004     // GC vm_operations can get caught at the safepoint, and the
4005     // heap is unparseable if they are caught. Grab the Heap_lock
4006     // to prevent this. The GC vm_operations will not be able to
4007     // queue until after the vm thread is dead.
4008     // After this point, we'll never emerge out of the safepoint before
4009     // the VM exits, so concurrent GC threads do not need to be explicitly
4010     // stopped; they remain inactive until the process exits.
4011     // Note: some concurrent G1 threads may be running during a safepoint,
4012     // but these will not be accessing the heap, just some G1-specific side
4013     // data structures that are not accessed by any other threads but them
4014     // after this point in a terminal safepoint.
4015 
4016     MutexLocker ml(Heap_lock);
4017 
4018     VMThread::wait_for_vm_thread_exit();
4019     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4020     VMThread::destroy();
4021   }
4022 
4023   // clean up ideal graph printers
4024 #if defined(COMPILER2) && !defined(PRODUCT)
4025   IdealGraphPrinter::clean_up();
4026 #endif
4027 
4028   // Now, all Java threads are gone except daemon threads. Daemon threads
4029   // running Java code or in VM are stopped by the Safepoint. However,
4030   // daemon threads executing native code are still running.  But they
4031   // will be stopped at native=>Java/VM barriers. Note that we can't
4032   // simply kill or suspend them, as it is inherently deadlock-prone.
4033 
4034 #ifndef PRODUCT
4035   // disable function tracing at JNI/JVM barriers
4036   TraceJNICalls = false;
4037   TraceJVMCalls = false;
4038   TraceRuntimeCalls = false;
4039 #endif
4040 
4041   VM_Exit::set_vm_exited();
4042 
4043   notify_vm_shutdown();
4044 
4045   delete thread;
4046 
4047   // exit_globals() will delete tty
4048   exit_globals();
4049 
4050   return true;
4051 }
4052 
4053 
4054 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4055   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4056   return is_supported_jni_version(version);
4057 }
4058 
4059 
4060 jboolean Threads::is_supported_jni_version(jint version) {
4061   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4062   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4063   if (version == JNI_VERSION_1_6) return JNI_TRUE;

4064   return JNI_FALSE;
4065 }
4066 
4067 
4068 void Threads::add(JavaThread* p, bool force_daemon) {
4069   // The threads lock must be owned at this point
4070   assert_locked_or_safepoint(Threads_lock);
4071 
4072   // See the comment for this method in thread.hpp for its purpose and
4073   // why it is called here.
4074   p->initialize_queues();
4075   p->set_next(_thread_list);
4076   _thread_list = p;
4077   _number_of_threads++;
4078   oop threadObj = p->threadObj();
4079   bool daemon = true;
4080   // Bootstrapping problem: threadObj can be null for initial
4081   // JavaThread (or for threads attached via JNI)
4082   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4083     _number_of_non_daemon_threads++;
4084     daemon = false;
4085   }
4086 
4087   p->set_safepoint_visible(true);
4088 
4089   ThreadService::add_thread(p, daemon);
4090 
4091   // Possible GC point.
4092   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4093 }
4094 
4095 void Threads::remove(JavaThread* p) {
4096   // Extra scope needed for Thread_lock, so we can check
4097   // that we do not remove thread without safepoint code notice
4098   { MutexLocker ml(Threads_lock);
4099 
4100     assert(includes(p), "p must be present");
4101 
4102     JavaThread* current = _thread_list;
4103     JavaThread* prev    = NULL;
4104 
4105     while (current != p) {
4106       prev    = current;
4107       current = current->next();
4108     }
4109 
4110     if (prev) {
4111       prev->set_next(current->next());
4112     } else {
4113       _thread_list = p->next();
4114     }
4115     _number_of_threads--;
4116     oop threadObj = p->threadObj();
4117     bool daemon = true;
4118     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4119       _number_of_non_daemon_threads--;
4120       daemon = false;
4121 
4122       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4123       // on destroy_vm will wake up.
4124       if (number_of_non_daemon_threads() == 1)
4125         Threads_lock->notify_all();
4126     }
4127     ThreadService::remove_thread(p, daemon);
4128 
4129     // Make sure that safepoint code disregard this thread. This is needed since
4130     // the thread might mess around with locks after this point. This can cause it
4131     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4132     // of this thread since it is removed from the queue.
4133     p->set_terminated_value();
4134 
4135     // Now, this thread is not visible to safepoint
4136     p->set_safepoint_visible(false);
4137     // once the thread becomes safepoint invisible, we can not use its per-thread
4138     // recorder. And Threads::do_threads() no longer walks this thread, so we have
4139     // to release its per-thread recorder here.
4140     MemTracker::thread_exiting(p);
4141   } // unlock Threads_lock
4142 
4143   // Since Events::log uses a lock, we grab it outside the Threads_lock
4144   Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4145 }
4146 
4147 // Threads_lock must be held when this is called (or must be called during a safepoint)
4148 bool Threads::includes(JavaThread* p) {
4149   assert(Threads_lock->is_locked(), "sanity check");
4150   ALL_JAVA_THREADS(q) {
4151     if (q == p ) {
4152       return true;
4153     }
4154   }
4155   return false;
4156 }
4157 
4158 // Operations on the Threads list for GC.  These are not explicitly locked,
4159 // but the garbage collector must provide a safe context for them to run.
4160 // In particular, these things should never be called when the Threads_lock
4161 // is held by some other thread. (Note: the Safepoint abstraction also
4162 // uses the Threads_lock to gurantee this property. It also makes sure that
4163 // all threads gets blocked when exiting or starting).
4164 
4165 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4166   ALL_JAVA_THREADS(p) {
4167     p->oops_do(f, cld_f, cf);
4168   }
4169   VMThread::vm_thread()->oops_do(f, cld_f, cf);
4170 }
4171 
4172 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4173   // Introduce a mechanism allowing parallel threads to claim threads as
4174   // root groups.  Overhead should be small enough to use all the time,
4175   // even in sequential code.
4176   SharedHeap* sh = SharedHeap::heap();
4177   // Cannot yet substitute active_workers for n_par_threads
4178   // because of G1CollectedHeap::verify() use of
4179   // SharedHeap::process_strong_roots().  n_par_threads == 0 will
4180   // turn off parallelism in process_strong_roots while active_workers
4181   // is being used for parallelism elsewhere.
4182   bool is_par = sh->n_par_threads() > 0;
4183   assert(!is_par ||
4184          (SharedHeap::heap()->n_par_threads() ==
4185           SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4186   int cp = SharedHeap::heap()->strong_roots_parity();
4187   ALL_JAVA_THREADS(p) {
4188     if (p->claim_oops_do(is_par, cp)) {
4189       p->oops_do(f, cld_f, cf);
4190     }
4191   }
4192   VMThread* vmt = VMThread::vm_thread();
4193   if (vmt->claim_oops_do(is_par, cp)) {
4194     vmt->oops_do(f, cld_f, cf);
4195   }
4196 }
4197 
4198 #if INCLUDE_ALL_GCS
4199 // Used by ParallelScavenge
4200 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4201   ALL_JAVA_THREADS(p) {
4202     q->enqueue(new ThreadRootsTask(p));
4203   }
4204   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4205 }
4206 
4207 // Used by Parallel Old
4208 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4209   ALL_JAVA_THREADS(p) {
4210     q->enqueue(new ThreadRootsMarkingTask(p));
4211   }
4212   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4213 }
4214 #endif // INCLUDE_ALL_GCS
4215 
4216 void Threads::nmethods_do(CodeBlobClosure* cf) {
4217   ALL_JAVA_THREADS(p) {
4218     p->nmethods_do(cf);
4219   }
4220   VMThread::vm_thread()->nmethods_do(cf);
4221 }
4222 
4223 void Threads::metadata_do(void f(Metadata*)) {
4224   ALL_JAVA_THREADS(p) {
4225     p->metadata_do(f);
4226   }
4227 }
4228 
4229 void Threads::gc_epilogue() {
4230   ALL_JAVA_THREADS(p) {
4231     p->gc_epilogue();
4232   }
4233 }
4234 
4235 void Threads::gc_prologue() {
4236   ALL_JAVA_THREADS(p) {
4237     p->gc_prologue();
4238   }
4239 }
4240 
4241 void Threads::deoptimized_wrt_marked_nmethods() {
4242   ALL_JAVA_THREADS(p) {
4243     p->deoptimized_wrt_marked_nmethods();
4244   }
4245 }
4246 
4247 
4248 // Get count Java threads that are waiting to enter the specified monitor.
4249 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4250   address monitor, bool doLock) {
4251   assert(doLock || SafepointSynchronize::is_at_safepoint(),
4252     "must grab Threads_lock or be at safepoint");
4253   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4254 
4255   int i = 0;
4256   {
4257     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4258     ALL_JAVA_THREADS(p) {
4259       if (p->is_Compiler_thread()) continue;
4260 
4261       address pending = (address)p->current_pending_monitor();
4262       if (pending == monitor) {             // found a match
4263         if (i < count) result->append(p);   // save the first count matches
4264         i++;
4265       }
4266     }
4267   }
4268   return result;
4269 }
4270 
4271 
4272 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4273   assert(doLock ||
4274          Threads_lock->owned_by_self() ||
4275          SafepointSynchronize::is_at_safepoint(),
4276          "must grab Threads_lock or be at safepoint");
4277 
4278   // NULL owner means not locked so we can skip the search
4279   if (owner == NULL) return NULL;
4280 
4281   {
4282     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4283     ALL_JAVA_THREADS(p) {
4284       // first, see if owner is the address of a Java thread
4285       if (owner == (address)p) return p;
4286     }
4287   }
4288   assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
4289   if (UseHeavyMonitors) return NULL;
4290 
4291   //
4292   // If we didn't find a matching Java thread and we didn't force use of
4293   // heavyweight monitors, then the owner is the stack address of the
4294   // Lock Word in the owning Java thread's stack.
4295   //
4296   JavaThread* the_owner = NULL;
4297   {
4298     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4299     ALL_JAVA_THREADS(q) {
4300       if (q->is_lock_owned(owner)) {
4301         the_owner = q;
4302         break;
4303       }
4304     }
4305   }
4306   assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4307   return the_owner;
4308 }
4309 
4310 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4311 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4312   char buf[32];
4313   st->print_cr(os::local_time_string(buf, sizeof(buf)));
4314 
4315   st->print_cr("Full thread dump %s (%s %s):",
4316                 Abstract_VM_Version::vm_name(),
4317                 Abstract_VM_Version::vm_release(),
4318                 Abstract_VM_Version::vm_info_string()
4319                );
4320   st->cr();
4321 
4322 #if INCLUDE_ALL_GCS
4323   // Dump concurrent locks
4324   ConcurrentLocksDump concurrent_locks;
4325   if (print_concurrent_locks) {
4326     concurrent_locks.dump_at_safepoint();
4327   }
4328 #endif // INCLUDE_ALL_GCS
4329 
4330   ALL_JAVA_THREADS(p) {
4331     ResourceMark rm;
4332     p->print_on(st);
4333     if (print_stacks) {
4334       if (internal_format) {
4335         p->trace_stack();
4336       } else {
4337         p->print_stack_on(st);
4338       }
4339     }
4340     st->cr();
4341 #if INCLUDE_ALL_GCS
4342     if (print_concurrent_locks) {
4343       concurrent_locks.print_locks_on(p, st);
4344     }
4345 #endif // INCLUDE_ALL_GCS
4346   }
4347 
4348   VMThread::vm_thread()->print_on(st);
4349   st->cr();
4350   Universe::heap()->print_gc_threads_on(st);
4351   WatcherThread* wt = WatcherThread::watcher_thread();
4352   if (wt != NULL) {
4353     wt->print_on(st);
4354     st->cr();
4355   }
4356   CompileBroker::print_compiler_threads_on(st);
4357   st->flush();
4358 }
4359 
4360 // Threads::print_on_error() is called by fatal error handler. It's possible
4361 // that VM is not at safepoint and/or current thread is inside signal handler.
4362 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4363 // memory (even in resource area), it might deadlock the error handler.
4364 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4365   bool found_current = false;
4366   st->print_cr("Java Threads: ( => current thread )");
4367   ALL_JAVA_THREADS(thread) {
4368     bool is_current = (current == thread);
4369     found_current = found_current || is_current;
4370 
4371     st->print("%s", is_current ? "=>" : "  ");
4372 
4373     st->print(PTR_FORMAT, thread);
4374     st->print(" ");
4375     thread->print_on_error(st, buf, buflen);
4376     st->cr();
4377   }
4378   st->cr();
4379 
4380   st->print_cr("Other Threads:");
4381   if (VMThread::vm_thread()) {
4382     bool is_current = (current == VMThread::vm_thread());
4383     found_current = found_current || is_current;
4384     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
4385 
4386     st->print(PTR_FORMAT, VMThread::vm_thread());
4387     st->print(" ");
4388     VMThread::vm_thread()->print_on_error(st, buf, buflen);
4389     st->cr();
4390   }
4391   WatcherThread* wt = WatcherThread::watcher_thread();
4392   if (wt != NULL) {
4393     bool is_current = (current == wt);
4394     found_current = found_current || is_current;
4395     st->print("%s", is_current ? "=>" : "  ");
4396 
4397     st->print(PTR_FORMAT, wt);
4398     st->print(" ");
4399     wt->print_on_error(st, buf, buflen);
4400     st->cr();
4401   }
4402   if (!found_current) {
4403     st->cr();
4404     st->print("=>" PTR_FORMAT " (exited) ", current);
4405     current->print_on_error(st, buf, buflen);
4406     st->cr();
4407   }
4408 }
4409 
4410 // Internal SpinLock and Mutex
4411 // Based on ParkEvent
4412 
4413 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4414 //
4415 // We employ SpinLocks _only for low-contention, fixed-length
4416 // short-duration critical sections where we're concerned
4417 // about native mutex_t or HotSpot Mutex:: latency.
4418 // The mux construct provides a spin-then-block mutual exclusion
4419 // mechanism.
4420 //
4421 // Testing has shown that contention on the ListLock guarding gFreeList
4422 // is common.  If we implement ListLock as a simple SpinLock it's common
4423 // for the JVM to devolve to yielding with little progress.  This is true
4424 // despite the fact that the critical sections protected by ListLock are
4425 // extremely short.
4426 //
4427 // TODO-FIXME: ListLock should be of type SpinLock.
4428 // We should make this a 1st-class type, integrated into the lock
4429 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4430 // should have sufficient padding to avoid false-sharing and excessive
4431 // cache-coherency traffic.
4432 
4433 
4434 typedef volatile int SpinLockT ;
4435 
4436 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4437   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4438      return ;   // normal fast-path return
4439   }
4440 
4441   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4442   TEVENT (SpinAcquire - ctx) ;
4443   int ctr = 0 ;
4444   int Yields = 0 ;
4445   for (;;) {
4446      while (*adr != 0) {
4447         ++ctr ;
4448         if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4449            if (Yields > 5) {
4450              // Consider using a simple NakedSleep() instead.
4451              // Then SpinAcquire could be called by non-JVM threads
4452              Thread::current()->_ParkEvent->park(1) ;
4453            } else {
4454              os::NakedYield() ;
4455              ++Yields ;
4456            }
4457         } else {
4458            SpinPause() ;
4459         }
4460      }
4461      if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4462   }
4463 }
4464 
4465 void Thread::SpinRelease (volatile int * adr) {
4466   assert (*adr != 0, "invariant") ;
4467   OrderAccess::fence() ;      // guarantee at least release consistency.
4468   // Roach-motel semantics.
4469   // It's safe if subsequent LDs and STs float "up" into the critical section,
4470   // but prior LDs and STs within the critical section can't be allowed
4471   // to reorder or float past the ST that releases the lock.
4472   *adr = 0 ;
4473 }
4474 
4475 // muxAcquire and muxRelease:
4476 //
4477 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4478 //    The LSB of the word is set IFF the lock is held.
4479 //    The remainder of the word points to the head of a singly-linked list
4480 //    of threads blocked on the lock.
4481 //
4482 // *  The current implementation of muxAcquire-muxRelease uses its own
4483 //    dedicated Thread._MuxEvent instance.  If we're interested in
4484 //    minimizing the peak number of extant ParkEvent instances then
4485 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4486 //    as certain invariants were satisfied.  Specifically, care would need
4487 //    to be taken with regards to consuming unpark() "permits".
4488 //    A safe rule of thumb is that a thread would never call muxAcquire()
4489 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4490 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4491 //    consume an unpark() permit intended for monitorenter, for instance.
4492 //    One way around this would be to widen the restricted-range semaphore
4493 //    implemented in park().  Another alternative would be to provide
4494 //    multiple instances of the PlatformEvent() for each thread.  One
4495 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4496 //
4497 // *  Usage:
4498 //    -- Only as leaf locks
4499 //    -- for short-term locking only as muxAcquire does not perform
4500 //       thread state transitions.
4501 //
4502 // Alternatives:
4503 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4504 //    but with parking or spin-then-park instead of pure spinning.
4505 // *  Use Taura-Oyama-Yonenzawa locks.
4506 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4507 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4508 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4509 //    acquiring threads use timers (ParkTimed) to detect and recover from
4510 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4511 //    boundaries by using placement-new.
4512 // *  Augment MCS with advisory back-link fields maintained with CAS().
4513 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4514 //    The validity of the backlinks must be ratified before we trust the value.
4515 //    If the backlinks are invalid the exiting thread must back-track through the
4516 //    the forward links, which are always trustworthy.
4517 // *  Add a successor indication.  The LockWord is currently encoded as
4518 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4519 //    to provide the usual futile-wakeup optimization.
4520 //    See RTStt for details.
4521 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4522 //
4523 
4524 
4525 typedef volatile intptr_t MutexT ;      // Mux Lock-word
4526 enum MuxBits { LOCKBIT = 1 } ;
4527 
4528 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4529   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4530   if (w == 0) return ;
4531   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4532      return ;
4533   }
4534 
4535   TEVENT (muxAcquire - Contention) ;
4536   ParkEvent * const Self = Thread::current()->_MuxEvent ;
4537   assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4538   for (;;) {
4539      int its = (os::is_MP() ? 100 : 0) + 1 ;
4540 
4541      // Optional spin phase: spin-then-park strategy
4542      while (--its >= 0) {
4543        w = *Lock ;
4544        if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4545           return ;
4546        }
4547      }
4548 
4549      Self->reset() ;
4550      Self->OnList = intptr_t(Lock) ;
4551      // The following fence() isn't _strictly necessary as the subsequent
4552      // CAS() both serializes execution and ratifies the fetched *Lock value.
4553      OrderAccess::fence();
4554      for (;;) {
4555         w = *Lock ;
4556         if ((w & LOCKBIT) == 0) {
4557             if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4558                 Self->OnList = 0 ;   // hygiene - allows stronger asserts
4559                 return ;
4560             }
4561             continue ;      // Interference -- *Lock changed -- Just retry
4562         }
4563         assert (w & LOCKBIT, "invariant") ;
4564         Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4565         if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4566      }
4567 
4568      while (Self->OnList != 0) {
4569         Self->park() ;
4570      }
4571   }
4572 }
4573 
4574 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4575   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4576   if (w == 0) return ;
4577   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4578     return ;
4579   }
4580 
4581   TEVENT (muxAcquire - Contention) ;
4582   ParkEvent * ReleaseAfter = NULL ;
4583   if (ev == NULL) {
4584     ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4585   }
4586   assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4587   for (;;) {
4588     guarantee (ev->OnList == 0, "invariant") ;
4589     int its = (os::is_MP() ? 100 : 0) + 1 ;
4590 
4591     // Optional spin phase: spin-then-park strategy
4592     while (--its >= 0) {
4593       w = *Lock ;
4594       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4595         if (ReleaseAfter != NULL) {
4596           ParkEvent::Release (ReleaseAfter) ;
4597         }
4598         return ;
4599       }
4600     }
4601 
4602     ev->reset() ;
4603     ev->OnList = intptr_t(Lock) ;
4604     // The following fence() isn't _strictly necessary as the subsequent
4605     // CAS() both serializes execution and ratifies the fetched *Lock value.
4606     OrderAccess::fence();
4607     for (;;) {
4608       w = *Lock ;
4609       if ((w & LOCKBIT) == 0) {
4610         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4611           ev->OnList = 0 ;
4612           // We call ::Release while holding the outer lock, thus
4613           // artificially lengthening the critical section.
4614           // Consider deferring the ::Release() until the subsequent unlock(),
4615           // after we've dropped the outer lock.
4616           if (ReleaseAfter != NULL) {
4617             ParkEvent::Release (ReleaseAfter) ;
4618           }
4619           return ;
4620         }
4621         continue ;      // Interference -- *Lock changed -- Just retry
4622       }
4623       assert (w & LOCKBIT, "invariant") ;
4624       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4625       if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4626     }
4627 
4628     while (ev->OnList != 0) {
4629       ev->park() ;
4630     }
4631   }
4632 }
4633 
4634 // Release() must extract a successor from the list and then wake that thread.
4635 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4636 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4637 // Release() would :
4638 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4639 // (B) Extract a successor from the private list "in-hand"
4640 // (C) attempt to CAS() the residual back into *Lock over null.
4641 //     If there were any newly arrived threads and the CAS() would fail.
4642 //     In that case Release() would detach the RATs, re-merge the list in-hand
4643 //     with the RATs and repeat as needed.  Alternately, Release() might
4644 //     detach and extract a successor, but then pass the residual list to the wakee.
4645 //     The wakee would be responsible for reattaching and remerging before it
4646 //     competed for the lock.
4647 //
4648 // Both "pop" and DMR are immune from ABA corruption -- there can be
4649 // multiple concurrent pushers, but only one popper or detacher.
4650 // This implementation pops from the head of the list.  This is unfair,
4651 // but tends to provide excellent throughput as hot threads remain hot.
4652 // (We wake recently run threads first).
4653 
4654 void Thread::muxRelease (volatile intptr_t * Lock)  {
4655   for (;;) {
4656     const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4657     assert (w & LOCKBIT, "invariant") ;
4658     if (w == LOCKBIT) return ;
4659     ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4660     assert (List != NULL, "invariant") ;
4661     assert (List->OnList == intptr_t(Lock), "invariant") ;
4662     ParkEvent * nxt = List->ListNext ;
4663 
4664     // The following CAS() releases the lock and pops the head element.
4665     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4666       continue ;
4667     }
4668     List->OnList = 0 ;
4669     OrderAccess::fence() ;
4670     List->unpark () ;
4671     return ;
4672   }
4673 }
4674 
4675 
4676 void Threads::verify() {
4677   ALL_JAVA_THREADS(p) {
4678     p->verify();
4679   }
4680   VMThread* thread = VMThread::vm_thread();
4681   if (thread != NULL) thread->verify();
4682 }
--- EOF ---