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