1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "interpreter/interpreter.hpp"
  33 #include "interpreter/linkResolver.hpp"
  34 #include "interpreter/oopMapCache.hpp"
  35 #include "jvmtifiles/jvmtiEnv.hpp"
  36 #include "memory/gcLocker.inline.hpp"
  37 #include "memory/metaspaceShared.hpp"
  38 #include "memory/oopFactory.hpp"
  39 #include "memory/universe.inline.hpp"
  40 #include "oops/instanceKlass.hpp"
  41 #include "oops/objArrayOop.hpp"
  42 #include "oops/oop.inline.hpp"
  43 #include "oops/symbol.hpp"
  44 #include "prims/jvm_misc.hpp"
  45 #include "prims/jvmtiExport.hpp"
  46 #include "prims/jvmtiThreadState.hpp"
  47 #include "prims/privilegedStack.hpp"
  48 #include "runtime/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/osThread.hpp"
  62 #include "runtime/safepoint.hpp"
  63 #include "runtime/sharedRuntime.hpp"
  64 #include "runtime/statSampler.hpp"
  65 #include "runtime/stubRoutines.hpp"
  66 #include "runtime/task.hpp"
  67 #include "runtime/thread.inline.hpp"
  68 #include "runtime/threadCritical.hpp"
  69 #include "runtime/threadLocalStorage.hpp"
  70 #include "runtime/vframe.hpp"
  71 #include "runtime/vframeArray.hpp"
  72 #include "runtime/vframe_hp.hpp"
  73 #include "runtime/vmThread.hpp"
  74 #include "runtime/vm_operations.hpp"
  75 #include "services/attachListener.hpp"
  76 #include "services/management.hpp"
  77 #include "services/memTracker.hpp"
  78 #include "services/threadService.hpp"
  79 #include "trace/tracing.hpp"
  80 #include "trace/traceMacros.hpp"
  81 #include "utilities/defaultStream.hpp"
  82 #include "utilities/dtrace.hpp"
  83 #include "utilities/events.hpp"
  84 #include "utilities/preserveException.hpp"
  85 #include "utilities/macros.hpp"
  86 #ifdef TARGET_OS_FAMILY_linux
  87 # include "os_linux.inline.hpp"
  88 #endif
  89 #ifdef TARGET_OS_FAMILY_solaris
  90 # include "os_solaris.inline.hpp"
  91 #endif
  92 #ifdef TARGET_OS_FAMILY_windows
  93 # include "os_windows.inline.hpp"
  94 #endif
  95 #ifdef TARGET_OS_FAMILY_bsd
  96 # include "os_bsd.inline.hpp"
  97 #endif
  98 #if INCLUDE_ALL_GCS
  99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
 102 #endif // INCLUDE_ALL_GCS
 103 #ifdef COMPILER1
 104 #include "c1/c1_Compiler.hpp"
 105 #endif
 106 #ifdef COMPILER2
 107 #include "opto/c2compiler.hpp"
 108 #include "opto/idealGraphPrinter.hpp"
 109 #endif
 110 
 111 #ifdef DTRACE_ENABLED
 112 
 113 // Only bother with this argument setup if dtrace is available
 114 
 115 #ifndef USDT2
 116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
 118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
 119   intptr_t, intptr_t, bool);
 120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
 121   intptr_t, intptr_t, bool);
 122 
 123 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 124   {                                                                        \
 125     ResourceMark rm(this);                                                 \
 126     int len = 0;                                                           \
 127     const char* name = (javathread)->get_thread_name();                    \
 128     len = strlen(name);                                                    \
 129     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
 130       name, len,                                                           \
 131       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 132       (javathread)->osthread()->thread_id(),                               \
 133       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 134   }
 135 
 136 #else /* USDT2 */
 137 
 138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
 139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
 140 
 141 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 142   {                                                                        \
 143     ResourceMark rm(this);                                                 \
 144     int len = 0;                                                           \
 145     const char* name = (javathread)->get_thread_name();                    \
 146     len = strlen(name);                                                    \
 147     HOTSPOT_THREAD_PROBE_##probe(  /* probe = start, stop */               \
 148       (char *) name, len,                                                           \
 149       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 150       (uintptr_t) (javathread)->osthread()->thread_id(),                               \
 151       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 152   }
 153 
 154 #endif /* USDT2 */
 155 
 156 #else //  ndef DTRACE_ENABLED
 157 
 158 #define DTRACE_THREAD_PROBE(probe, javathread)
 159 
 160 #endif // ndef DTRACE_ENABLED
 161 
 162 
 163 // Class hierarchy
 164 // - Thread
 165 //   - VMThread
 166 //   - WatcherThread
 167 //   - ConcurrentMarkSweepThread
 168 //   - JavaThread
 169 //     - CompilerThread
 170 
 171 // ======= Thread ========
 172 // Support for forcing alignment of thread objects for biased locking
 173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 174   if (UseBiasedLocking) {
 175     const int alignment = markOopDesc::biased_lock_alignment;
 176     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 177     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 178                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 179                                               AllocFailStrategy::RETURN_NULL);
 180     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
 181     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 182            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 183            "JavaThread alignment code overflowed allocated storage");
 184     if (TraceBiasedLocking) {
 185       if (aligned_addr != real_malloc_addr)
 186         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 187                       real_malloc_addr, aligned_addr);
 188     }
 189     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 190     return aligned_addr;
 191   } else {
 192     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 193                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 194   }
 195 }
 196 
 197 void Thread::operator delete(void* p) {
 198   if (UseBiasedLocking) {
 199     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
 200     FreeHeap(real_malloc_addr, mtThread);
 201   } else {
 202     FreeHeap(p, mtThread);
 203   }
 204 }
 205 
 206 
 207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 208 // JavaThread
 209 
 210 
 211 Thread::Thread() {
 212   // stack and get_thread
 213   set_stack_base(NULL);
 214   set_stack_size(0);
 215   set_self_raw_id(0);
 216   set_lgrp_id(-1);
 217 
 218   // allocated data structures
 219   set_osthread(NULL);
 220   set_resource_area(new (mtThread)ResourceArea());
 221   DEBUG_ONLY(_current_resource_mark = NULL;)
 222   set_handle_area(new (mtThread) HandleArea(NULL));
 223   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 224   set_active_handles(NULL);
 225   set_free_handle_block(NULL);
 226   set_last_handle_mark(NULL);
 227 
 228   // This initial value ==> never claimed.
 229   _oops_do_parity = 0;
 230 
 231   // the handle mark links itself to last_handle_mark
 232   new HandleMark(this);
 233 
 234   // plain initialization
 235   debug_only(_owned_locks = NULL;)
 236   debug_only(_allow_allocation_count = 0;)
 237   NOT_PRODUCT(_allow_safepoint_count = 0;)
 238   NOT_PRODUCT(_skip_gcalot = false;)
 239   CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
 240   _jvmti_env_iteration_count = 0;
 241   set_allocated_bytes(0);
 242   _vm_operation_started_count = 0;
 243   _vm_operation_completed_count = 0;
 244   _current_pending_monitor = NULL;
 245   _current_pending_monitor_is_from_java = true;
 246   _current_waiting_monitor = NULL;
 247   _num_nested_signal = 0;
 248   omFreeList = NULL ;
 249   omFreeCount = 0 ;
 250   omFreeProvision = 32 ;
 251   omInUseList = NULL ;
 252   omInUseCount = 0 ;
 253 
 254 #ifdef ASSERT
 255   _visited_for_critical_count = false;
 256 #endif
 257 
 258   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
 259   _suspend_flags = 0;
 260 
 261   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 262   _hashStateX = os::random() ;
 263   _hashStateY = 842502087 ;
 264   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
 265   _hashStateW = 273326509 ;
 266 
 267   _OnTrap   = 0 ;
 268   _schedctl = NULL ;
 269   _Stalled  = 0 ;
 270   _TypeTag  = 0x2BAD ;
 271 
 272   // Many of the following fields are effectively final - immutable
 273   // Note that nascent threads can't use the Native Monitor-Mutex
 274   // construct until the _MutexEvent is initialized ...
 275   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 276   // we might instead use a stack of ParkEvents that we could provision on-demand.
 277   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 278   // and ::Release()
 279   _ParkEvent   = ParkEvent::Allocate (this) ;
 280   _SleepEvent  = ParkEvent::Allocate (this) ;
 281   _MutexEvent  = ParkEvent::Allocate (this) ;
 282   _MuxEvent    = ParkEvent::Allocate (this) ;
 283 
 284 #ifdef CHECK_UNHANDLED_OOPS
 285   if (CheckUnhandledOops) {
 286     _unhandled_oops = new UnhandledOops(this);
 287   }
 288 #endif // CHECK_UNHANDLED_OOPS
 289 #ifdef ASSERT
 290   if (UseBiasedLocking) {
 291     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 292     assert(this == _real_malloc_address ||
 293            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 294            "bug in forced alignment of thread objects");
 295   }
 296 #endif /* ASSERT */
 297 }
 298 
 299 void Thread::initialize_thread_local_storage() {
 300   // Note: Make sure this method only calls
 301   // non-blocking operations. Otherwise, it might not work
 302   // with the thread-startup/safepoint interaction.
 303 
 304   // During Java thread startup, safepoint code should allow this
 305   // method to complete because it may need to allocate memory to
 306   // store information for the new thread.
 307 
 308   // initialize structure dependent on thread local storage
 309   ThreadLocalStorage::set_thread(this);
 310 }
 311 
 312 void Thread::record_stack_base_and_size() {
 313   set_stack_base(os::current_stack_base());
 314   set_stack_size(os::current_stack_size());
 315   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 316   // in initialize_thread(). Without the adjustment, stack size is
 317   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 318   // So far, only Solaris has real implementation of initialize_thread().
 319   //
 320   // set up any platform-specific state.
 321   os::initialize_thread(this);
 322 
 323 #if INCLUDE_NMT
 324   // record thread's native stack, stack grows downward
 325   address stack_low_addr = stack_base() - stack_size();
 326   MemTracker::record_thread_stack(stack_low_addr, stack_size(), this,
 327       CURRENT_PC);
 328 #endif // INCLUDE_NMT
 329 }
 330 
 331 
 332 Thread::~Thread() {
 333   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 334   ObjectSynchronizer::omFlush (this) ;
 335 
 336   EVENT_THREAD_DESTRUCT(this);
 337 
 338   // stack_base can be NULL if the thread is never started or exited before
 339   // record_stack_base_and_size called. Although, we would like to ensure
 340   // that all started threads do call record_stack_base_and_size(), there is
 341   // not proper way to enforce that.
 342 #if INCLUDE_NMT
 343   if (_stack_base != NULL) {
 344     address low_stack_addr = stack_base() - stack_size();
 345     MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
 346 #ifdef ASSERT
 347     set_stack_base(NULL);
 348 #endif
 349   }
 350 #endif // INCLUDE_NMT
 351 
 352   // deallocate data structures
 353   delete resource_area();
 354   // since the handle marks are using the handle area, we have to deallocated the root
 355   // handle mark before deallocating the thread's handle area,
 356   assert(last_handle_mark() != NULL, "check we have an element");
 357   delete last_handle_mark();
 358   assert(last_handle_mark() == NULL, "check we have reached the end");
 359 
 360   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 361   // We NULL out the fields for good hygiene.
 362   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 363   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 364   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 365   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 366 
 367   delete handle_area();
 368   delete metadata_handles();
 369 
 370   // osthread() can be NULL, if creation of thread failed.
 371   if (osthread() != NULL) os::free_thread(osthread());
 372 
 373   delete _SR_lock;
 374 
 375   // clear thread local storage if the Thread is deleting itself
 376   if (this == Thread::current()) {
 377     ThreadLocalStorage::set_thread(NULL);
 378   } else {
 379     // In the case where we're not the current thread, invalidate all the
 380     // caches in case some code tries to get the current thread or the
 381     // thread that was destroyed, and gets stale information.
 382     ThreadLocalStorage::invalidate_all();
 383   }
 384   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 385 }
 386 
 387 // NOTE: dummy function for assertion purpose.
 388 void Thread::run() {
 389   ShouldNotReachHere();
 390 }
 391 
 392 #ifdef ASSERT
 393 // Private method to check for dangling thread pointer
 394 void check_for_dangling_thread_pointer(Thread *thread) {
 395  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 396          "possibility of dangling Thread pointer");
 397 }
 398 #endif
 399 
 400 
 401 #ifndef PRODUCT
 402 // Tracing method for basic thread operations
 403 void Thread::trace(const char* msg, const Thread* const thread) {
 404   if (!TraceThreadEvents) return;
 405   ResourceMark rm;
 406   ThreadCritical tc;
 407   const char *name = "non-Java thread";
 408   int prio = -1;
 409   if (thread->is_Java_thread()
 410       && !thread->is_Compiler_thread()) {
 411     // The Threads_lock must be held to get information about
 412     // this thread but may not be in some situations when
 413     // tracing  thread events.
 414     bool release_Threads_lock = false;
 415     if (!Threads_lock->owned_by_self()) {
 416       Threads_lock->lock();
 417       release_Threads_lock = true;
 418     }
 419     JavaThread* jt = (JavaThread *)thread;
 420     name = (char *)jt->get_thread_name();
 421     oop thread_oop = jt->threadObj();
 422     if (thread_oop != NULL) {
 423       prio = java_lang_Thread::priority(thread_oop);
 424     }
 425     if (release_Threads_lock) {
 426       Threads_lock->unlock();
 427     }
 428   }
 429   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 430 }
 431 #endif
 432 
 433 
 434 ThreadPriority Thread::get_priority(const Thread* const thread) {
 435   trace("get priority", thread);
 436   ThreadPriority priority;
 437   // Can return an error!
 438   (void)os::get_priority(thread, priority);
 439   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 440   return priority;
 441 }
 442 
 443 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 444   trace("set priority", thread);
 445   debug_only(check_for_dangling_thread_pointer(thread);)
 446   // Can return an error!
 447   (void)os::set_priority(thread, priority);
 448 }
 449 
 450 
 451 void Thread::start(Thread* thread) {
 452   trace("start", thread);
 453   // Start is different from resume in that its safety is guaranteed by context or
 454   // being called from a Java method synchronized on the Thread object.
 455   if (!DisableStartThread) {
 456     if (thread->is_Java_thread()) {
 457       // Initialize the thread state to RUNNABLE before starting this thread.
 458       // Can not set it after the thread started because we do not know the
 459       // exact thread state at that time. It could be in MONITOR_WAIT or
 460       // in SLEEPING or some other state.
 461       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 462                                           java_lang_Thread::RUNNABLE);
 463     }
 464     os::start_thread(thread);
 465   }
 466 }
 467 
 468 // Enqueue a VM_Operation to do the job for us - sometime later
 469 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 470   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 471   VMThread::execute(vm_stop);
 472 }
 473 
 474 
 475 //
 476 // Check if an external suspend request has completed (or has been
 477 // cancelled). Returns true if the thread is externally suspended and
 478 // false otherwise.
 479 //
 480 // The bits parameter returns information about the code path through
 481 // the routine. Useful for debugging:
 482 //
 483 // set in is_ext_suspend_completed():
 484 // 0x00000001 - routine was entered
 485 // 0x00000010 - routine return false at end
 486 // 0x00000100 - thread exited (return false)
 487 // 0x00000200 - suspend request cancelled (return false)
 488 // 0x00000400 - thread suspended (return true)
 489 // 0x00001000 - thread is in a suspend equivalent state (return true)
 490 // 0x00002000 - thread is native and walkable (return true)
 491 // 0x00004000 - thread is native_trans and walkable (needed retry)
 492 //
 493 // set in wait_for_ext_suspend_completion():
 494 // 0x00010000 - routine was entered
 495 // 0x00020000 - suspend request cancelled before loop (return false)
 496 // 0x00040000 - thread suspended before loop (return true)
 497 // 0x00080000 - suspend request cancelled in loop (return false)
 498 // 0x00100000 - thread suspended in loop (return true)
 499 // 0x00200000 - suspend not completed during retry loop (return false)
 500 //
 501 
 502 // Helper class for tracing suspend wait debug bits.
 503 //
 504 // 0x00000100 indicates that the target thread exited before it could
 505 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 506 // 0x00080000 each indicate a cancelled suspend request so they don't
 507 // count as wait failures either.
 508 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 509 
 510 class TraceSuspendDebugBits : public StackObj {
 511  private:
 512   JavaThread * jt;
 513   bool         is_wait;
 514   bool         called_by_wait;  // meaningful when !is_wait
 515   uint32_t *   bits;
 516 
 517  public:
 518   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 519                         uint32_t *_bits) {
 520     jt             = _jt;
 521     is_wait        = _is_wait;
 522     called_by_wait = _called_by_wait;
 523     bits           = _bits;
 524   }
 525 
 526   ~TraceSuspendDebugBits() {
 527     if (!is_wait) {
 528 #if 1
 529       // By default, don't trace bits for is_ext_suspend_completed() calls.
 530       // That trace is very chatty.
 531       return;
 532 #else
 533       if (!called_by_wait) {
 534         // If tracing for is_ext_suspend_completed() is enabled, then only
 535         // trace calls to it from wait_for_ext_suspend_completion()
 536         return;
 537       }
 538 #endif
 539     }
 540 
 541     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 542       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 543         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 544         ResourceMark rm;
 545 
 546         tty->print_cr(
 547             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 548             jt->get_thread_name(), *bits);
 549 
 550         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 551       }
 552     }
 553   }
 554 };
 555 #undef DEBUG_FALSE_BITS
 556 
 557 
 558 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 559   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 560 
 561   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 562   bool do_trans_retry;           // flag to force the retry
 563 
 564   *bits |= 0x00000001;
 565 
 566   do {
 567     do_trans_retry = false;
 568 
 569     if (is_exiting()) {
 570       // Thread is in the process of exiting. This is always checked
 571       // first to reduce the risk of dereferencing a freed JavaThread.
 572       *bits |= 0x00000100;
 573       return false;
 574     }
 575 
 576     if (!is_external_suspend()) {
 577       // Suspend request is cancelled. This is always checked before
 578       // is_ext_suspended() to reduce the risk of a rogue resume
 579       // confusing the thread that made the suspend request.
 580       *bits |= 0x00000200;
 581       return false;
 582     }
 583 
 584     if (is_ext_suspended()) {
 585       // thread is suspended
 586       *bits |= 0x00000400;
 587       return true;
 588     }
 589 
 590     // Now that we no longer do hard suspends of threads running
 591     // native code, the target thread can be changing thread state
 592     // while we are in this routine:
 593     //
 594     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 595     //
 596     // We save a copy of the thread state as observed at this moment
 597     // and make our decision about suspend completeness based on the
 598     // copy. This closes the race where the thread state is seen as
 599     // _thread_in_native_trans in the if-thread_blocked check, but is
 600     // seen as _thread_blocked in if-thread_in_native_trans check.
 601     JavaThreadState save_state = thread_state();
 602 
 603     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 604       // If the thread's state is _thread_blocked and this blocking
 605       // condition is known to be equivalent to a suspend, then we can
 606       // consider the thread to be externally suspended. This means that
 607       // the code that sets _thread_blocked has been modified to do
 608       // self-suspension if the blocking condition releases. We also
 609       // used to check for CONDVAR_WAIT here, but that is now covered by
 610       // the _thread_blocked with self-suspension check.
 611       //
 612       // Return true since we wouldn't be here unless there was still an
 613       // external suspend request.
 614       *bits |= 0x00001000;
 615       return true;
 616     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 617       // Threads running native code will self-suspend on native==>VM/Java
 618       // transitions. If its stack is walkable (should always be the case
 619       // unless this function is called before the actual java_suspend()
 620       // call), then the wait is done.
 621       *bits |= 0x00002000;
 622       return true;
 623     } else if (!called_by_wait && !did_trans_retry &&
 624                save_state == _thread_in_native_trans &&
 625                frame_anchor()->walkable()) {
 626       // The thread is transitioning from thread_in_native to another
 627       // thread state. check_safepoint_and_suspend_for_native_trans()
 628       // will force the thread to self-suspend. If it hasn't gotten
 629       // there yet we may have caught the thread in-between the native
 630       // code check above and the self-suspend. Lucky us. If we were
 631       // called by wait_for_ext_suspend_completion(), then it
 632       // will be doing the retries so we don't have to.
 633       //
 634       // Since we use the saved thread state in the if-statement above,
 635       // there is a chance that the thread has already transitioned to
 636       // _thread_blocked by the time we get here. In that case, we will
 637       // make a single unnecessary pass through the logic below. This
 638       // doesn't hurt anything since we still do the trans retry.
 639 
 640       *bits |= 0x00004000;
 641 
 642       // Once the thread leaves thread_in_native_trans for another
 643       // thread state, we break out of this retry loop. We shouldn't
 644       // need this flag to prevent us from getting back here, but
 645       // sometimes paranoia is good.
 646       did_trans_retry = true;
 647 
 648       // We wait for the thread to transition to a more usable state.
 649       for (int i = 1; i <= SuspendRetryCount; i++) {
 650         // We used to do an "os::yield_all(i)" call here with the intention
 651         // that yielding would increase on each retry. However, the parameter
 652         // is ignored on Linux which means the yield didn't scale up. Waiting
 653         // on the SR_lock below provides a much more predictable scale up for
 654         // the delay. It also provides a simple/direct point to check for any
 655         // safepoint requests from the VMThread
 656 
 657         // temporarily drops SR_lock while doing wait with safepoint check
 658         // (if we're a JavaThread - the WatcherThread can also call this)
 659         // and increase delay with each retry
 660         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 661 
 662         // check the actual thread state instead of what we saved above
 663         if (thread_state() != _thread_in_native_trans) {
 664           // the thread has transitioned to another thread state so
 665           // try all the checks (except this one) one more time.
 666           do_trans_retry = true;
 667           break;
 668         }
 669       } // end retry loop
 670 
 671 
 672     }
 673   } while (do_trans_retry);
 674 
 675   *bits |= 0x00000010;
 676   return false;
 677 }
 678 
 679 //
 680 // Wait for an external suspend request to complete (or be cancelled).
 681 // Returns true if the thread is externally suspended and false otherwise.
 682 //
 683 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 684        uint32_t *bits) {
 685   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 686                              false /* !called_by_wait */, bits);
 687 
 688   // local flag copies to minimize SR_lock hold time
 689   bool is_suspended;
 690   bool pending;
 691   uint32_t reset_bits;
 692 
 693   // set a marker so is_ext_suspend_completed() knows we are the caller
 694   *bits |= 0x00010000;
 695 
 696   // We use reset_bits to reinitialize the bits value at the top of
 697   // each retry loop. This allows the caller to make use of any
 698   // unused bits for their own marking purposes.
 699   reset_bits = *bits;
 700 
 701   {
 702     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 703     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 704                                             delay, bits);
 705     pending = is_external_suspend();
 706   }
 707   // must release SR_lock to allow suspension to complete
 708 
 709   if (!pending) {
 710     // A cancelled suspend request is the only false return from
 711     // is_ext_suspend_completed() that keeps us from entering the
 712     // retry loop.
 713     *bits |= 0x00020000;
 714     return false;
 715   }
 716 
 717   if (is_suspended) {
 718     *bits |= 0x00040000;
 719     return true;
 720   }
 721 
 722   for (int i = 1; i <= retries; i++) {
 723     *bits = reset_bits;  // reinit to only track last retry
 724 
 725     // We used to do an "os::yield_all(i)" call here with the intention
 726     // that yielding would increase on each retry. However, the parameter
 727     // is ignored on Linux which means the yield didn't scale up. Waiting
 728     // on the SR_lock below provides a much more predictable scale up for
 729     // the delay. It also provides a simple/direct point to check for any
 730     // safepoint requests from the VMThread
 731 
 732     {
 733       MutexLocker ml(SR_lock());
 734       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 735       // can also call this)  and increase delay with each retry
 736       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 737 
 738       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 739                                               delay, bits);
 740 
 741       // It is possible for the external suspend request to be cancelled
 742       // (by a resume) before the actual suspend operation is completed.
 743       // Refresh our local copy to see if we still need to wait.
 744       pending = is_external_suspend();
 745     }
 746 
 747     if (!pending) {
 748       // A cancelled suspend request is the only false return from
 749       // is_ext_suspend_completed() that keeps us from staying in the
 750       // retry loop.
 751       *bits |= 0x00080000;
 752       return false;
 753     }
 754 
 755     if (is_suspended) {
 756       *bits |= 0x00100000;
 757       return true;
 758     }
 759   } // end retry loop
 760 
 761   // thread did not suspend after all our retries
 762   *bits |= 0x00200000;
 763   return false;
 764 }
 765 
 766 #ifndef PRODUCT
 767 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 768 
 769   // This should not need to be atomic as the only way for simultaneous
 770   // updates is via interrupts. Even then this should be rare or non-existent
 771   // and we don't care that much anyway.
 772 
 773   int index = _jmp_ring_index;
 774   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 775   _jmp_ring[index]._target = (intptr_t) target;
 776   _jmp_ring[index]._instruction = (intptr_t) instr;
 777   _jmp_ring[index]._file = file;
 778   _jmp_ring[index]._line = line;
 779 }
 780 #endif /* PRODUCT */
 781 
 782 // Called by flat profiler
 783 // Callers have already called wait_for_ext_suspend_completion
 784 // The assertion for that is currently too complex to put here:
 785 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 786   bool gotframe = false;
 787   // self suspension saves needed state.
 788   if (has_last_Java_frame() && _anchor.walkable()) {
 789      *_fr = pd_last_frame();
 790      gotframe = true;
 791   }
 792   return gotframe;
 793 }
 794 
 795 void Thread::interrupt(Thread* thread) {
 796   trace("interrupt", thread);
 797   debug_only(check_for_dangling_thread_pointer(thread);)
 798   os::interrupt(thread);
 799 }
 800 
 801 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 802   trace("is_interrupted", thread);
 803   debug_only(check_for_dangling_thread_pointer(thread);)
 804   // Note:  If clear_interrupted==false, this simply fetches and
 805   // returns the value of the field osthread()->interrupted().
 806   return os::is_interrupted(thread, clear_interrupted);
 807 }
 808 
 809 
 810 // GC Support
 811 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 812   jint thread_parity = _oops_do_parity;
 813   if (thread_parity != strong_roots_parity) {
 814     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 815     if (res == thread_parity) {
 816       return true;
 817     } else {
 818       guarantee(res == strong_roots_parity, "Or else what?");
 819       assert(SharedHeap::heap()->workers()->active_workers() > 0,
 820          "Should only fail when parallel.");
 821       return false;
 822     }
 823   }
 824   assert(SharedHeap::heap()->workers()->active_workers() > 0,
 825          "Should only fail when parallel.");
 826   return false;
 827 }
 828 
 829 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
 830   active_handles()->oops_do(f);
 831   // Do oop for ThreadShadow
 832   f->do_oop((oop*)&_pending_exception);
 833   handle_area()->oops_do(f);
 834 }
 835 
 836 void Thread::nmethods_do(CodeBlobClosure* cf) {
 837   // no nmethods in a generic thread...
 838 }
 839 
 840 void Thread::metadata_do(void f(Metadata*)) {
 841   if (metadata_handles() != NULL) {
 842     for (int i = 0; i< metadata_handles()->length(); i++) {
 843       f(metadata_handles()->at(i));
 844     }
 845   }
 846 }
 847 
 848 void Thread::print_on(outputStream* st) const {
 849   // get_priority assumes osthread initialized
 850   if (osthread() != NULL) {
 851     int os_prio;
 852     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 853       st->print("os_prio=%d ", os_prio);
 854     }
 855     st->print("tid=" INTPTR_FORMAT " ", this);
 856     osthread()->print_on(st);
 857   }
 858   debug_only(if (WizardMode) print_owned_locks_on(st);)
 859 }
 860 
 861 // Thread::print_on_error() is called by fatal error handler. Don't use
 862 // any lock or allocate memory.
 863 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 864   if      (is_VM_thread())                  st->print("VMThread");
 865   else if (is_Compiler_thread())            st->print("CompilerThread");
 866   else if (is_Java_thread())                st->print("JavaThread");
 867   else if (is_GC_task_thread())             st->print("GCTaskThread");
 868   else if (is_Watcher_thread())             st->print("WatcherThread");
 869   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 870   else st->print("Thread");
 871 
 872   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 873             _stack_base - _stack_size, _stack_base);
 874 
 875   if (osthread()) {
 876     st->print(" [id=%d]", osthread()->thread_id());
 877   }
 878 }
 879 
 880 #ifdef ASSERT
 881 void Thread::print_owned_locks_on(outputStream* st) const {
 882   Monitor *cur = _owned_locks;
 883   if (cur == NULL) {
 884     st->print(" (no locks) ");
 885   } else {
 886     st->print_cr(" Locks owned:");
 887     while(cur) {
 888       cur->print_on(st);
 889       cur = cur->next();
 890     }
 891   }
 892 }
 893 
 894 static int ref_use_count  = 0;
 895 
 896 bool Thread::owns_locks_but_compiled_lock() const {
 897   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 898     if (cur != Compile_lock) return true;
 899   }
 900   return false;
 901 }
 902 
 903 
 904 #endif
 905 
 906 #ifndef PRODUCT
 907 
 908 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 909 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 910 // no threads which allow_vm_block's are held
 911 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 912     // Check if current thread is allowed to block at a safepoint
 913     if (!(_allow_safepoint_count == 0))
 914       fatal("Possible safepoint reached by thread that does not allow it");
 915     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 916       fatal("LEAF method calling lock?");
 917     }
 918 
 919 #ifdef ASSERT
 920     if (potential_vm_operation && is_Java_thread()
 921         && !Universe::is_bootstrapping()) {
 922       // Make sure we do not hold any locks that the VM thread also uses.
 923       // This could potentially lead to deadlocks
 924       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 925         // Threads_lock is special, since the safepoint synchronization will not start before this is
 926         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 927         // since it is used to transfer control between JavaThreads and the VMThread
 928         // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
 929         if ( (cur->allow_vm_block() &&
 930               cur != Threads_lock &&
 931               cur != Compile_lock &&               // Temporary: should not be necessary when we get separate compilation
 932               cur != VMOperationRequest_lock &&
 933               cur != VMOperationQueue_lock) ||
 934               cur->rank() == Mutex::special) {
 935           warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 936         }
 937       }
 938     }
 939 
 940     if (GCALotAtAllSafepoints) {
 941       // We could enter a safepoint here and thus have a gc
 942       InterfaceSupport::check_gc_alot();
 943     }
 944 #endif
 945 }
 946 #endif
 947 
 948 bool Thread::is_in_stack(address adr) const {
 949   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 950   address end = os::current_stack_pointer();
 951   // Allow non Java threads to call this without stack_base
 952   if (_stack_base == NULL) return true;
 953   if (stack_base() >= adr && adr >= end) return true;
 954 
 955   return false;
 956 }
 957 
 958 
 959 bool Thread::is_in_usable_stack(address adr) const {
 960   size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
 961   size_t usable_stack_size = _stack_size - stack_guard_size;
 962 
 963   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
 964 }
 965 
 966 
 967 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 968 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 969 // used for compilation in the future. If that change is made, the need for these methods
 970 // should be revisited, and they should be removed if possible.
 971 
 972 bool Thread::is_lock_owned(address adr) const {
 973   return on_local_stack(adr);
 974 }
 975 
 976 bool Thread::set_as_starting_thread() {
 977  // NOTE: this must be called inside the main thread.
 978   return os::create_main_thread((JavaThread*)this);
 979 }
 980 
 981 static void initialize_class(Symbol* class_name, TRAPS) {
 982   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 983   InstanceKlass::cast(klass)->initialize(CHECK);
 984 }
 985 
 986 
 987 // Creates the initial ThreadGroup
 988 static Handle create_initial_thread_group(TRAPS) {
 989   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
 990   instanceKlassHandle klass (THREAD, k);
 991 
 992   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
 993   {
 994     JavaValue result(T_VOID);
 995     JavaCalls::call_special(&result,
 996                             system_instance,
 997                             klass,
 998                             vmSymbols::object_initializer_name(),
 999                             vmSymbols::void_method_signature(),
1000                             CHECK_NH);
1001   }
1002   Universe::set_system_thread_group(system_instance());
1003 
1004   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1005   {
1006     JavaValue result(T_VOID);
1007     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1008     JavaCalls::call_special(&result,
1009                             main_instance,
1010                             klass,
1011                             vmSymbols::object_initializer_name(),
1012                             vmSymbols::threadgroup_string_void_signature(),
1013                             system_instance,
1014                             string,
1015                             CHECK_NH);
1016   }
1017   return main_instance;
1018 }
1019 
1020 // Creates the initial Thread
1021 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1022   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1023   instanceKlassHandle klass (THREAD, k);
1024   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1025 
1026   java_lang_Thread::set_thread(thread_oop(), thread);
1027   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1028   thread->set_threadObj(thread_oop());
1029 
1030   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1031 
1032   JavaValue result(T_VOID);
1033   JavaCalls::call_special(&result, thread_oop,
1034                                    klass,
1035                                    vmSymbols::object_initializer_name(),
1036                                    vmSymbols::threadgroup_string_void_signature(),
1037                                    thread_group,
1038                                    string,
1039                                    CHECK_NULL);
1040   return thread_oop();
1041 }
1042 
1043 static void call_initializeSystemClass(TRAPS) {
1044   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1045   instanceKlassHandle klass (THREAD, k);
1046 
1047   JavaValue result(T_VOID);
1048   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1049                                          vmSymbols::void_method_signature(), CHECK);
1050 }
1051 
1052 char java_runtime_name[128] = "";
1053 char java_runtime_version[128] = "";
1054 
1055 // extract the JRE name from sun.misc.Version.java_runtime_name
1056 static const char* get_java_runtime_name(TRAPS) {
1057   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1058                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1059   fieldDescriptor fd;
1060   bool found = k != NULL &&
1061                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1062                                                         vmSymbols::string_signature(), &fd);
1063   if (found) {
1064     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1065     if (name_oop == NULL)
1066       return NULL;
1067     const char* name = java_lang_String::as_utf8_string(name_oop,
1068                                                         java_runtime_name,
1069                                                         sizeof(java_runtime_name));
1070     return name;
1071   } else {
1072     return NULL;
1073   }
1074 }
1075 
1076 // extract the JRE version from sun.misc.Version.java_runtime_version
1077 static const char* get_java_runtime_version(TRAPS) {
1078   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1079                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1080   fieldDescriptor fd;
1081   bool found = k != NULL &&
1082                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1083                                                         vmSymbols::string_signature(), &fd);
1084   if (found) {
1085     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1086     if (name_oop == NULL)
1087       return NULL;
1088     const char* name = java_lang_String::as_utf8_string(name_oop,
1089                                                         java_runtime_version,
1090                                                         sizeof(java_runtime_version));
1091     return name;
1092   } else {
1093     return NULL;
1094   }
1095 }
1096 
1097 // General purpose hook into Java code, run once when the VM is initialized.
1098 // The Java library method itself may be changed independently from the VM.
1099 static void call_postVMInitHook(TRAPS) {
1100   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1101   instanceKlassHandle klass (THREAD, k);
1102   if (klass.not_null()) {
1103     JavaValue result(T_VOID);
1104     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1105                                            vmSymbols::void_method_signature(),
1106                                            CHECK);
1107   }
1108 }
1109 
1110 static void reset_vm_info_property(TRAPS) {
1111   // the vm info string
1112   ResourceMark rm(THREAD);
1113   const char *vm_info = VM_Version::vm_info_string();
1114 
1115   // java.lang.System class
1116   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1117   instanceKlassHandle klass (THREAD, k);
1118 
1119   // setProperty arguments
1120   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1121   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1122 
1123   // return value
1124   JavaValue r(T_OBJECT);
1125 
1126   // public static String setProperty(String key, String value);
1127   JavaCalls::call_static(&r,
1128                          klass,
1129                          vmSymbols::setProperty_name(),
1130                          vmSymbols::string_string_string_signature(),
1131                          key_str,
1132                          value_str,
1133                          CHECK);
1134 }
1135 
1136 
1137 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1138   assert(thread_group.not_null(), "thread group should be specified");
1139   assert(threadObj() == NULL, "should only create Java thread object once");
1140 
1141   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1142   instanceKlassHandle klass (THREAD, k);
1143   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1144 
1145   java_lang_Thread::set_thread(thread_oop(), this);
1146   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1147   set_threadObj(thread_oop());
1148 
1149   JavaValue result(T_VOID);
1150   if (thread_name != NULL) {
1151     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1152     // Thread gets assigned specified name and null target
1153     JavaCalls::call_special(&result,
1154                             thread_oop,
1155                             klass,
1156                             vmSymbols::object_initializer_name(),
1157                             vmSymbols::threadgroup_string_void_signature(),
1158                             thread_group, // Argument 1
1159                             name,         // Argument 2
1160                             THREAD);
1161   } else {
1162     // Thread gets assigned name "Thread-nnn" and null target
1163     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1164     JavaCalls::call_special(&result,
1165                             thread_oop,
1166                             klass,
1167                             vmSymbols::object_initializer_name(),
1168                             vmSymbols::threadgroup_runnable_void_signature(),
1169                             thread_group, // Argument 1
1170                             Handle(),     // Argument 2
1171                             THREAD);
1172   }
1173 
1174 
1175   if (daemon) {
1176       java_lang_Thread::set_daemon(thread_oop());
1177   }
1178 
1179   if (HAS_PENDING_EXCEPTION) {
1180     return;
1181   }
1182 
1183   KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1184   Handle threadObj(this, this->threadObj());
1185 
1186   JavaCalls::call_special(&result,
1187                          thread_group,
1188                          group,
1189                          vmSymbols::add_method_name(),
1190                          vmSymbols::thread_void_signature(),
1191                          threadObj,          // Arg 1
1192                          THREAD);
1193 
1194 
1195 }
1196 
1197 // NamedThread --  non-JavaThread subclasses with multiple
1198 // uniquely named instances should derive from this.
1199 NamedThread::NamedThread() : Thread() {
1200   _name = NULL;
1201   _processed_thread = NULL;
1202 }
1203 
1204 NamedThread::~NamedThread() {
1205   if (_name != NULL) {
1206     FREE_C_HEAP_ARRAY(char, _name, mtThread);
1207     _name = NULL;
1208   }
1209 }
1210 
1211 void NamedThread::set_name(const char* format, ...) {
1212   guarantee(_name == NULL, "Only get to set name once.");
1213   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1214   guarantee(_name != NULL, "alloc failure");
1215   va_list ap;
1216   va_start(ap, format);
1217   jio_vsnprintf(_name, max_name_len, format, ap);
1218   va_end(ap);
1219 }
1220 
1221 // ======= WatcherThread ========
1222 
1223 // The watcher thread exists to simulate timer interrupts.  It should
1224 // be replaced by an abstraction over whatever native support for
1225 // timer interrupts exists on the platform.
1226 
1227 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1228 bool WatcherThread::_startable = false;
1229 volatile bool  WatcherThread::_should_terminate = false;
1230 
1231 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1232   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1233   if (os::create_thread(this, os::watcher_thread)) {
1234     _watcher_thread = this;
1235 
1236     // Set the watcher thread to the highest OS priority which should not be
1237     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1238     // is created. The only normal thread using this priority is the reference
1239     // handler thread, which runs for very short intervals only.
1240     // If the VMThread's priority is not lower than the WatcherThread profiling
1241     // will be inaccurate.
1242     os::set_priority(this, MaxPriority);
1243     if (!DisableStartThread) {
1244       os::start_thread(this);
1245     }
1246   }
1247 }
1248 
1249 int WatcherThread::sleep() const {
1250   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1251 
1252   // remaining will be zero if there are no tasks,
1253   // causing the WatcherThread to sleep until a task is
1254   // enrolled
1255   int remaining = PeriodicTask::time_to_wait();
1256   int time_slept = 0;
1257 
1258   // we expect this to timeout - we only ever get unparked when
1259   // we should terminate or when a new task has been enrolled
1260   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1261 
1262   jlong time_before_loop = os::javaTimeNanos();
1263 
1264   for (;;) {
1265     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1266     jlong now = os::javaTimeNanos();
1267 
1268     if (remaining == 0) {
1269         // if we didn't have any tasks we could have waited for a long time
1270         // consider the time_slept zero and reset time_before_loop
1271         time_slept = 0;
1272         time_before_loop = now;
1273     } else {
1274         // need to recalculate since we might have new tasks in _tasks
1275         time_slept = (int) ((now - time_before_loop) / 1000000);
1276     }
1277 
1278     // Change to task list or spurious wakeup of some kind
1279     if (timedout || _should_terminate) {
1280         break;
1281     }
1282 
1283     remaining = PeriodicTask::time_to_wait();
1284     if (remaining == 0) {
1285         // Last task was just disenrolled so loop around and wait until
1286         // another task gets enrolled
1287         continue;
1288     }
1289 
1290     remaining -= time_slept;
1291     if (remaining <= 0)
1292       break;
1293   }
1294 
1295   return time_slept;
1296 }
1297 
1298 void WatcherThread::run() {
1299   assert(this == watcher_thread(), "just checking");
1300 
1301   this->record_stack_base_and_size();
1302   this->initialize_thread_local_storage();
1303   this->set_active_handles(JNIHandleBlock::allocate_block());
1304   while(!_should_terminate) {
1305     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1306     assert(watcher_thread() == this,  "thread consistency check");
1307 
1308     // Calculate how long it'll be until the next PeriodicTask work
1309     // should be done, and sleep that amount of time.
1310     int time_waited = sleep();
1311 
1312     if (is_error_reported()) {
1313       // A fatal error has happened, the error handler(VMError::report_and_die)
1314       // should abort JVM after creating an error log file. However in some
1315       // rare cases, the error handler itself might deadlock. Here we try to
1316       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1317       //
1318       // This code is in WatcherThread because WatcherThread wakes up
1319       // periodically so the fatal error handler doesn't need to do anything;
1320       // also because the WatcherThread is less likely to crash than other
1321       // threads.
1322 
1323       for (;;) {
1324         if (!ShowMessageBoxOnError
1325          && (OnError == NULL || OnError[0] == '\0')
1326          && Arguments::abort_hook() == NULL) {
1327              os::sleep(this, 2 * 60 * 1000, false);
1328              fdStream err(defaultStream::output_fd());
1329              err.print_raw_cr("# [ timer expired, abort... ]");
1330              // skip atexit/vm_exit/vm_abort hooks
1331              os::die();
1332         }
1333 
1334         // Wake up 5 seconds later, the fatal handler may reset OnError or
1335         // ShowMessageBoxOnError when it is ready to abort.
1336         os::sleep(this, 5 * 1000, false);
1337       }
1338     }
1339 
1340     PeriodicTask::real_time_tick(time_waited);
1341   }
1342 
1343   // Signal that it is terminated
1344   {
1345     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1346     _watcher_thread = NULL;
1347     Terminator_lock->notify();
1348   }
1349 
1350   // Thread destructor usually does this..
1351   ThreadLocalStorage::set_thread(NULL);
1352 }
1353 
1354 void WatcherThread::start() {
1355   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1356 
1357   if (watcher_thread() == NULL && _startable) {
1358     _should_terminate = false;
1359     // Create the single instance of WatcherThread
1360     new WatcherThread();
1361   }
1362 }
1363 
1364 void WatcherThread::make_startable() {
1365   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366   _startable = true;
1367 }
1368 
1369 void WatcherThread::stop() {
1370   {
1371     MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1372     _should_terminate = true;
1373     OrderAccess::fence();  // ensure WatcherThread sees update in main loop
1374 
1375     WatcherThread* watcher = watcher_thread();
1376     if (watcher != NULL)
1377       watcher->unpark();
1378   }
1379 
1380   // it is ok to take late safepoints here, if needed
1381   MutexLocker mu(Terminator_lock);
1382 
1383   while(watcher_thread() != NULL) {
1384     // This wait should make safepoint checks, wait without a timeout,
1385     // and wait as a suspend-equivalent condition.
1386     //
1387     // Note: If the FlatProfiler is running, then this thread is waiting
1388     // for the WatcherThread to terminate and the WatcherThread, via the
1389     // FlatProfiler task, is waiting for the external suspend request on
1390     // this thread to complete. wait_for_ext_suspend_completion() will
1391     // eventually timeout, but that takes time. Making this wait a
1392     // suspend-equivalent condition solves that timeout problem.
1393     //
1394     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1395                           Mutex::_as_suspend_equivalent_flag);
1396   }
1397 }
1398 
1399 void WatcherThread::unpark() {
1400   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1401   PeriodicTask_lock->notify();
1402 }
1403 
1404 void WatcherThread::print_on(outputStream* st) const {
1405   st->print("\"%s\" ", name());
1406   Thread::print_on(st);
1407   st->cr();
1408 }
1409 
1410 // ======= JavaThread ========
1411 
1412 // A JavaThread is a normal Java thread
1413 
1414 void JavaThread::initialize() {
1415   // Initialize fields
1416 
1417   // Set the claimed par_id to -1 (ie not claiming any par_ids)
1418   set_claimed_par_id(-1);
1419 
1420   set_saved_exception_pc(NULL);
1421   set_threadObj(NULL);
1422   _anchor.clear();
1423   set_entry_point(NULL);
1424   set_jni_functions(jni_functions());
1425   set_callee_target(NULL);
1426   set_vm_result(NULL);
1427   set_vm_result_2(NULL);
1428   set_vframe_array_head(NULL);
1429   set_vframe_array_last(NULL);
1430   set_deferred_locals(NULL);
1431   set_deopt_mark(NULL);
1432   set_deopt_nmethod(NULL);
1433   clear_must_deopt_id();
1434   set_monitor_chunks(NULL);
1435   set_next(NULL);
1436   set_thread_state(_thread_new);
1437 #if INCLUDE_NMT
1438   set_recorder(NULL);
1439 #endif
1440   _terminated = _not_terminated;
1441   _privileged_stack_top = NULL;
1442   _array_for_gc = NULL;
1443   _suspend_equivalent = false;
1444   _in_deopt_handler = 0;
1445   _doing_unsafe_access = false;
1446   _stack_guard_state = stack_guard_unused;
1447   (void)const_cast<oop&>(_exception_oop = NULL);
1448   _exception_pc  = 0;
1449   _exception_handler_pc = 0;
1450   _is_method_handle_return = 0;
1451   _jvmti_thread_state= NULL;
1452   _should_post_on_exceptions_flag = JNI_FALSE;
1453   _jvmti_get_loaded_classes_closure = NULL;
1454   _interp_only_mode    = 0;
1455   _special_runtime_exit_condition = _no_async_condition;
1456   _pending_async_exception = NULL;
1457   _thread_stat = NULL;
1458   _thread_stat = new ThreadStatistics();
1459   _blocked_on_compilation = false;
1460   _jni_active_critical = 0;
1461   _do_not_unlock_if_synchronized = false;
1462   _cached_monitor_info = NULL;
1463   _parker = Parker::Allocate(this) ;
1464 
1465 #ifndef PRODUCT
1466   _jmp_ring_index = 0;
1467   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1468     record_jump(NULL, NULL, NULL, 0);
1469   }
1470 #endif /* PRODUCT */
1471 
1472   set_thread_profiler(NULL);
1473   if (FlatProfiler::is_active()) {
1474     // This is where we would decide to either give each thread it's own profiler
1475     // or use one global one from FlatProfiler,
1476     // or up to some count of the number of profiled threads, etc.
1477     ThreadProfiler* pp = new ThreadProfiler();
1478     pp->engage();
1479     set_thread_profiler(pp);
1480   }
1481 
1482   // Setup safepoint state info for this thread
1483   ThreadSafepointState::create(this);
1484 
1485   debug_only(_java_call_counter = 0);
1486 
1487   // JVMTI PopFrame support
1488   _popframe_condition = popframe_inactive;
1489   _popframe_preserved_args = NULL;
1490   _popframe_preserved_args_size = 0;
1491 
1492   pd_initialize();
1493 }
1494 
1495 #if INCLUDE_ALL_GCS
1496 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1497 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1498 #endif // INCLUDE_ALL_GCS
1499 
1500 JavaThread::JavaThread(bool is_attaching_via_jni) :
1501   Thread()
1502 #if INCLUDE_ALL_GCS
1503   , _satb_mark_queue(&_satb_mark_queue_set),
1504   _dirty_card_queue(&_dirty_card_queue_set)
1505 #endif // INCLUDE_ALL_GCS
1506 {
1507   initialize();
1508   if (is_attaching_via_jni) {
1509     _jni_attach_state = _attaching_via_jni;
1510   } else {
1511     _jni_attach_state = _not_attaching_via_jni;
1512   }
1513   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1514   _safepoint_visible = false;
1515 }
1516 
1517 bool JavaThread::reguard_stack(address cur_sp) {
1518   if (_stack_guard_state != stack_guard_yellow_disabled) {
1519     return true; // Stack already guarded or guard pages not needed.
1520   }
1521 
1522   if (register_stack_overflow()) {
1523     // For those architectures which have separate register and
1524     // memory stacks, we must check the register stack to see if
1525     // it has overflowed.
1526     return false;
1527   }
1528 
1529   // Java code never executes within the yellow zone: the latter is only
1530   // there to provoke an exception during stack banging.  If java code
1531   // is executing there, either StackShadowPages should be larger, or
1532   // some exception code in c1, c2 or the interpreter isn't unwinding
1533   // when it should.
1534   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1535 
1536   enable_stack_yellow_zone();
1537   return true;
1538 }
1539 
1540 bool JavaThread::reguard_stack(void) {
1541   return reguard_stack(os::current_stack_pointer());
1542 }
1543 
1544 
1545 void JavaThread::block_if_vm_exited() {
1546   if (_terminated == _vm_exited) {
1547     // _vm_exited is set at safepoint, and Threads_lock is never released
1548     // we will block here forever
1549     Threads_lock->lock_without_safepoint_check();
1550     ShouldNotReachHere();
1551   }
1552 }
1553 
1554 
1555 // Remove this ifdef when C1 is ported to the compiler interface.
1556 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1557 
1558 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1559   Thread()
1560 #if INCLUDE_ALL_GCS
1561   , _satb_mark_queue(&_satb_mark_queue_set),
1562   _dirty_card_queue(&_dirty_card_queue_set)
1563 #endif // INCLUDE_ALL_GCS
1564 {
1565   if (TraceThreadEvents) {
1566     tty->print_cr("creating thread %p", this);
1567   }
1568   initialize();
1569   _jni_attach_state = _not_attaching_via_jni;
1570   set_entry_point(entry_point);
1571   // Create the native thread itself.
1572   // %note runtime_23
1573   os::ThreadType thr_type = os::java_thread;
1574   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1575                                                      os::java_thread;
1576   os::create_thread(this, thr_type, stack_sz);
1577   _safepoint_visible = false;
1578   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1579   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1580   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1581   // the exception consists of creating the exception object & initializing it, initialization
1582   // will leave the VM via a JavaCall and then all locks must be unlocked).
1583   //
1584   // The thread is still suspended when we reach here. Thread must be explicit started
1585   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1586   // by calling Threads:add. The reason why this is not done here, is because the thread
1587   // object must be fully initialized (take a look at JVM_Start)
1588 }
1589 
1590 JavaThread::~JavaThread() {
1591   if (TraceThreadEvents) {
1592       tty->print_cr("terminate thread %p", this);
1593   }
1594 
1595   // By now, this thread should already be invisible to safepoint,
1596   // and its per-thread recorder also collected.
1597   assert(!is_safepoint_visible(), "wrong state");
1598 #if INCLUDE_NMT
1599   assert(get_recorder() == NULL, "Already collected");
1600 #endif // INCLUDE_NMT
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 validity 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, CLDToOopClosure* 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     typeArrayOop name = java_lang_Thread::name(thread_obj);
2930     if (name != NULL) {
2931       if (buf == NULL) {
2932         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2933       }
2934       else {
2935         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), 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   // Add the new thread to the Threads list and set it in motion.
3030   // We must have threads lock in order to call Threads::add.
3031   // It is crucial that we do not block before the thread is
3032   // added to the Threads list for if a GC happens, then the java_thread oop
3033   // will not be visited by GC.
3034   Threads::add(this);
3035 }
3036 
3037 oop JavaThread::current_park_blocker() {
3038   // Support for JSR-166 locks
3039   oop thread_oop = threadObj();
3040   if (thread_oop != NULL &&
3041       JDK_Version::current().supports_thread_park_blocker()) {
3042     return java_lang_Thread::park_blocker(thread_oop);
3043   }
3044   return NULL;
3045 }
3046 
3047 
3048 void JavaThread::print_stack_on(outputStream* st) {
3049   if (!has_last_Java_frame()) return;
3050   ResourceMark rm;
3051   HandleMark   hm;
3052 
3053   RegisterMap reg_map(this);
3054   vframe* start_vf = last_java_vframe(&reg_map);
3055   int count = 0;
3056   for (vframe* f = start_vf; f; f = f->sender() ) {
3057     if (f->is_java_frame()) {
3058       javaVFrame* jvf = javaVFrame::cast(f);
3059       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3060 
3061       // Print out lock information
3062       if (JavaMonitorsInStackTrace) {
3063         jvf->print_lock_info_on(st, count);
3064       }
3065     } else {
3066       // Ignore non-Java frames
3067     }
3068 
3069     // Bail-out case for too deep stacks
3070     count++;
3071     if (MaxJavaStackTraceDepth == count) return;
3072   }
3073 }
3074 
3075 
3076 // JVMTI PopFrame support
3077 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3078   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3079   if (in_bytes(size_in_bytes) != 0) {
3080     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3081     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3082     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3083   }
3084 }
3085 
3086 void* JavaThread::popframe_preserved_args() {
3087   return _popframe_preserved_args;
3088 }
3089 
3090 ByteSize JavaThread::popframe_preserved_args_size() {
3091   return in_ByteSize(_popframe_preserved_args_size);
3092 }
3093 
3094 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3095   int sz = in_bytes(popframe_preserved_args_size());
3096   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3097   return in_WordSize(sz / wordSize);
3098 }
3099 
3100 void JavaThread::popframe_free_preserved_args() {
3101   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3102   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3103   _popframe_preserved_args = NULL;
3104   _popframe_preserved_args_size = 0;
3105 }
3106 
3107 #ifndef PRODUCT
3108 
3109 void JavaThread::trace_frames() {
3110   tty->print_cr("[Describe stack]");
3111   int frame_no = 1;
3112   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3113     tty->print("  %d. ", frame_no++);
3114     fst.current()->print_value_on(tty,this);
3115     tty->cr();
3116   }
3117 }
3118 
3119 class PrintAndVerifyOopClosure: public OopClosure {
3120  protected:
3121   template <class T> inline void do_oop_work(T* p) {
3122     oop obj = oopDesc::load_decode_heap_oop(p);
3123     if (obj == NULL) return;
3124     tty->print(INTPTR_FORMAT ": ", p);
3125     if (obj->is_oop_or_null()) {
3126       if (obj->is_objArray()) {
3127         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3128       } else {
3129         obj->print();
3130       }
3131     } else {
3132       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3133     }
3134     tty->cr();
3135   }
3136  public:
3137   virtual void do_oop(oop* p) { do_oop_work(p); }
3138   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3139 };
3140 
3141 
3142 static void oops_print(frame* f, const RegisterMap *map) {
3143   PrintAndVerifyOopClosure print;
3144   f->print_value();
3145   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3146 }
3147 
3148 // Print our all the locations that contain oops and whether they are
3149 // valid or not.  This useful when trying to find the oldest frame
3150 // where an oop has gone bad since the frame walk is from youngest to
3151 // oldest.
3152 void JavaThread::trace_oops() {
3153   tty->print_cr("[Trace oops]");
3154   frames_do(oops_print);
3155 }
3156 
3157 
3158 #ifdef ASSERT
3159 // Print or validate the layout of stack frames
3160 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3161   ResourceMark rm;
3162   PRESERVE_EXCEPTION_MARK;
3163   FrameValues values;
3164   int frame_no = 0;
3165   for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3166     fst.current()->describe(values, ++frame_no);
3167     if (depth == frame_no) break;
3168   }
3169   if (validate_only) {
3170     values.validate();
3171   } else {
3172     tty->print_cr("[Describe stack layout]");
3173     values.print(this);
3174   }
3175 }
3176 #endif
3177 
3178 void JavaThread::trace_stack_from(vframe* start_vf) {
3179   ResourceMark rm;
3180   int vframe_no = 1;
3181   for (vframe* f = start_vf; f; f = f->sender() ) {
3182     if (f->is_java_frame()) {
3183       javaVFrame::cast(f)->print_activation(vframe_no++);
3184     } else {
3185       f->print();
3186     }
3187     if (vframe_no > StackPrintLimit) {
3188       tty->print_cr("...<more frames>...");
3189       return;
3190     }
3191   }
3192 }
3193 
3194 
3195 void JavaThread::trace_stack() {
3196   if (!has_last_Java_frame()) return;
3197   ResourceMark rm;
3198   HandleMark   hm;
3199   RegisterMap reg_map(this);
3200   trace_stack_from(last_java_vframe(&reg_map));
3201 }
3202 
3203 
3204 #endif // PRODUCT
3205 
3206 
3207 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3208   assert(reg_map != NULL, "a map must be given");
3209   frame f = last_frame();
3210   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3211     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3212   }
3213   return NULL;
3214 }
3215 
3216 
3217 Klass* JavaThread::security_get_caller_class(int depth) {
3218   vframeStream vfst(this);
3219   vfst.security_get_caller_frame(depth);
3220   if (!vfst.at_end()) {
3221     return vfst.method()->method_holder();
3222   }
3223   return NULL;
3224 }
3225 
3226 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3227   assert(thread->is_Compiler_thread(), "must be compiler thread");
3228   CompileBroker::compiler_thread_loop();
3229 }
3230 
3231 // Create a CompilerThread
3232 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3233 : JavaThread(&compiler_thread_entry) {
3234   _env   = NULL;
3235   _log   = NULL;
3236   _task  = NULL;
3237   _queue = queue;
3238   _counters = counters;
3239   _buffer_blob = NULL;
3240   _scanned_nmethod = NULL;
3241   _compiler = NULL;
3242 
3243 #ifndef PRODUCT
3244   _ideal_graph_printer = NULL;
3245 #endif
3246 }
3247 
3248 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3249   JavaThread::oops_do(f, cld_f, cf);
3250   if (_scanned_nmethod != NULL && cf != NULL) {
3251     // Safepoints can occur when the sweeper is scanning an nmethod so
3252     // process it here to make sure it isn't unloaded in the middle of
3253     // a scan.
3254     cf->do_code_blob(_scanned_nmethod);
3255   }
3256 }
3257 
3258 
3259 // ======= Threads ========
3260 
3261 // The Threads class links together all active threads, and provides
3262 // operations over all threads.  It is protected by its own Mutex
3263 // lock, which is also used in other contexts to protect thread
3264 // operations from having the thread being operated on from exiting
3265 // and going away unexpectedly (e.g., safepoint synchronization)
3266 
3267 JavaThread* Threads::_thread_list = NULL;
3268 int         Threads::_number_of_threads = 0;
3269 int         Threads::_number_of_non_daemon_threads = 0;
3270 int         Threads::_return_code = 0;
3271 size_t      JavaThread::_stack_size_at_create = 0;
3272 #ifdef ASSERT
3273 bool        Threads::_vm_complete = false;
3274 #endif
3275 
3276 // All JavaThreads
3277 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3278 
3279 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3280 void Threads::threads_do(ThreadClosure* tc) {
3281   assert_locked_or_safepoint(Threads_lock);
3282   // ALL_JAVA_THREADS iterates through all JavaThreads
3283   ALL_JAVA_THREADS(p) {
3284     tc->do_thread(p);
3285   }
3286   // Someday we could have a table or list of all non-JavaThreads.
3287   // For now, just manually iterate through them.
3288   tc->do_thread(VMThread::vm_thread());
3289   Universe::heap()->gc_threads_do(tc);
3290   WatcherThread *wt = WatcherThread::watcher_thread();
3291   // Strictly speaking, the following NULL check isn't sufficient to make sure
3292   // the data for WatcherThread is still valid upon being examined. However,
3293   // considering that WatchThread terminates when the VM is on the way to
3294   // exit at safepoint, the chance of the above is extremely small. The right
3295   // way to prevent termination of WatcherThread would be to acquire
3296   // Terminator_lock, but we can't do that without violating the lock rank
3297   // checking in some cases.
3298   if (wt != NULL)
3299     tc->do_thread(wt);
3300 
3301   // If CompilerThreads ever become non-JavaThreads, add them here
3302 }
3303 
3304 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3305 
3306   extern void JDK_Version_init();
3307 
3308   // Check version
3309   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3310 
3311   // Initialize the output stream module
3312   ostream_init();
3313 
3314   // Process java launcher properties.
3315   Arguments::process_sun_java_launcher_properties(args);
3316 
3317   // Initialize the os module before using TLS
3318   os::init();
3319 
3320   // Initialize system properties.
3321   Arguments::init_system_properties();
3322 
3323   // So that JDK version can be used as a discriminator when parsing arguments
3324   JDK_Version_init();
3325 
3326   // Update/Initialize System properties after JDK version number is known
3327   Arguments::init_version_specific_system_properties();
3328 
3329   // Parse arguments
3330   jint parse_result = Arguments::parse(args);
3331   if (parse_result != JNI_OK) return parse_result;
3332 
3333   os::init_before_ergo();
3334 
3335   jint ergo_result = Arguments::apply_ergo();
3336   if (ergo_result != JNI_OK) return ergo_result;
3337 
3338   if (PauseAtStartup) {
3339     os::pause();
3340   }
3341 
3342 #ifndef USDT2
3343   HS_DTRACE_PROBE(hotspot, vm__init__begin);
3344 #else /* USDT2 */
3345   HOTSPOT_VM_INIT_BEGIN();
3346 #endif /* USDT2 */
3347 
3348   // Record VM creation timing statistics
3349   TraceVmCreationTime create_vm_timer;
3350   create_vm_timer.start();
3351 
3352   // Timing (must come after argument parsing)
3353   TraceTime timer("Create VM", TraceStartupTime);
3354 
3355   // Initialize the os module after parsing the args
3356   jint os_init_2_result = os::init_2();
3357   if (os_init_2_result != JNI_OK) return os_init_2_result;
3358 
3359   jint adjust_after_os_result = Arguments::adjust_after_os();
3360   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3361 
3362   // initialize TLS
3363   ThreadLocalStorage::init();
3364 
3365   // Bootstrap native memory tracking, so it can start recording memory
3366   // activities before worker thread is started. This is the first phase
3367   // of bootstrapping, VM is currently running in single-thread mode.
3368   MemTracker::bootstrap_single_thread();
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   // Second phase of bootstrapping, VM is about entering multi-thread mode
3421   MemTracker::bootstrap_multi_thread();
3422 
3423   // Initialize global modules
3424   jint status = init_globals();
3425   if (status != JNI_OK) {
3426     delete main_thread;
3427     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3428     return status;
3429   }
3430 
3431   // Should be done after the heap is fully created
3432   main_thread->cache_global_variables();
3433 
3434   HandleMark hm;
3435 
3436   { MutexLocker mu(Threads_lock);
3437     Threads::add(main_thread);
3438   }
3439 
3440   // Any JVMTI raw monitors entered in onload will transition into
3441   // real raw monitor. VM is setup enough here for raw monitor enter.
3442   JvmtiExport::transition_pending_onload_raw_monitors();
3443 
3444   // Fully start NMT
3445   MemTracker::start();
3446 
3447   // Create the VMThread
3448   { TraceTime timer("Start VMThread", TraceStartupTime);
3449     VMThread::create();
3450     Thread* vmthread = VMThread::vm_thread();
3451 
3452     if (!os::create_thread(vmthread, os::vm_thread))
3453       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3454 
3455     // Wait for the VM thread to become ready, and VMThread::run to initialize
3456     // Monitors can have spurious returns, must always check another state flag
3457     {
3458       MutexLocker ml(Notify_lock);
3459       os::start_thread(vmthread);
3460       while (vmthread->active_handles() == NULL) {
3461         Notify_lock->wait();
3462       }
3463     }
3464   }
3465 
3466   assert (Universe::is_fully_initialized(), "not initialized");
3467   if (VerifyDuringStartup) {
3468     // Make sure we're starting with a clean slate.
3469     VM_Verify verify_op;
3470     VMThread::execute(&verify_op);
3471   }
3472 
3473   EXCEPTION_MARK;
3474 
3475   // At this point, the Universe is initialized, but we have not executed
3476   // any byte code.  Now is a good time (the only time) to dump out the
3477   // internal state of the JVM for sharing.
3478   if (DumpSharedSpaces) {
3479     MetaspaceShared::preload_and_dump(CHECK_0);
3480     ShouldNotReachHere();
3481   }
3482 
3483   // Always call even when there are not JVMTI environments yet, since environments
3484   // may be attached late and JVMTI must track phases of VM execution
3485   JvmtiExport::enter_start_phase();
3486 
3487   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3488   JvmtiExport::post_vm_start();
3489 
3490   {
3491     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3492 
3493     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3494       create_vm_init_libraries();
3495     }
3496 
3497     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3498 
3499     // Initialize java_lang.System (needed before creating the thread)
3500     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3501     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3502     Handle thread_group = create_initial_thread_group(CHECK_0);
3503     Universe::set_main_thread_group(thread_group());
3504     initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3505     oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3506     main_thread->set_threadObj(thread_object);
3507     // Set thread status to running since main thread has
3508     // been started and running.
3509     java_lang_Thread::set_thread_status(thread_object,
3510                                         java_lang_Thread::RUNNABLE);
3511 
3512     // The VM creates & returns objects of this class. Make sure it's initialized.
3513     initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3514 
3515     // The VM preresolves methods to these classes. Make sure that they get initialized
3516     initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3517     initialize_class(vmSymbols::java_lang_ref_Finalizer(),  CHECK_0);
3518     call_initializeSystemClass(CHECK_0);
3519 
3520     // get the Java runtime name after java.lang.System is initialized
3521     JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3522     JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3523 
3524     // an instance of OutOfMemory exception has been allocated earlier
3525     initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3526     initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3527     initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3528     initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3529     initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3530     initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3531     initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3532     initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3533   }
3534 
3535   // See        : bugid 4211085.
3536   // Background : the static initializer of java.lang.Compiler tries to read
3537   //              property"java.compiler" and read & write property "java.vm.info".
3538   //              When a security manager is installed through the command line
3539   //              option "-Djava.security.manager", the above properties are not
3540   //              readable and the static initializer for java.lang.Compiler fails
3541   //              resulting in a NoClassDefFoundError.  This can happen in any
3542   //              user code which calls methods in java.lang.Compiler.
3543   // Hack :       the hack is to pre-load and initialize this class, so that only
3544   //              system domains are on the stack when the properties are read.
3545   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3546   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3547   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3548   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3549   //              Once that is done, we should remove this hack.
3550   initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3551 
3552   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3553   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3554   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3555   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3556   // This should also be taken out as soon as 4211383 gets fixed.
3557   reset_vm_info_property(CHECK_0);
3558 
3559   quicken_jni_functions();
3560 
3561   // Must be run after init_ft which initializes ft_enabled
3562   if (TRACE_INITIALIZE() != JNI_OK) {
3563     vm_exit_during_initialization("Failed to initialize tracing backend");
3564   }
3565 
3566   // Set flag that basic initialization has completed. Used by exceptions and various
3567   // debug stuff, that does not work until all basic classes have been initialized.
3568   set_init_completed();
3569 
3570 #ifndef USDT2
3571   HS_DTRACE_PROBE(hotspot, vm__init__end);
3572 #else /* USDT2 */
3573   HOTSPOT_VM_INIT_END();
3574 #endif /* USDT2 */
3575 
3576   // record VM initialization completion time
3577 #if INCLUDE_MANAGEMENT
3578   Management::record_vm_init_completed();
3579 #endif // INCLUDE_MANAGEMENT
3580 
3581   // Compute system loader. Note that this has to occur after set_init_completed, since
3582   // valid exceptions may be thrown in the process.
3583   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3584   // set_init_completed has just been called, causing exceptions not to be shortcut
3585   // anymore. We call vm_exit_during_initialization directly instead.
3586   SystemDictionary::compute_java_system_loader(THREAD);
3587   if (HAS_PENDING_EXCEPTION) {
3588     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3589   }
3590 
3591 #if INCLUDE_ALL_GCS
3592   // Support for ConcurrentMarkSweep. This should be cleaned up
3593   // and better encapsulated. The ugly nested if test would go away
3594   // once things are properly refactored. XXX YSR
3595   if (UseConcMarkSweepGC || UseG1GC) {
3596     if (UseConcMarkSweepGC) {
3597       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3598     } else {
3599       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3600     }
3601     if (HAS_PENDING_EXCEPTION) {
3602       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3603     }
3604   }
3605 #endif // INCLUDE_ALL_GCS
3606 
3607   // Always call even when there are not JVMTI environments yet, since environments
3608   // may be attached late and JVMTI must track phases of VM execution
3609   JvmtiExport::enter_live_phase();
3610 
3611   // Signal Dispatcher needs to be started before VMInit event is posted
3612   os::signal_init();
3613 
3614   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3615   if (!DisableAttachMechanism) {
3616     AttachListener::vm_start();
3617     if (StartAttachListener || AttachListener::init_at_startup()) {
3618       AttachListener::init();
3619     }
3620   }
3621 
3622   // Launch -Xrun agents
3623   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3624   // back-end can launch with -Xdebug -Xrunjdwp.
3625   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3626     create_vm_init_libraries();
3627   }
3628 
3629   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3630   JvmtiExport::post_vm_initialized();
3631 
3632   if (TRACE_START() != JNI_OK) {
3633     vm_exit_during_initialization("Failed to start tracing backend.");
3634   }
3635 
3636   if (CleanChunkPoolAsync) {
3637     Chunk::start_chunk_pool_cleaner_task();
3638   }
3639 
3640   // initialize compiler(s)
3641 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3642   CompileBroker::compilation_init();
3643 #endif
3644 
3645   if (EnableInvokeDynamic) {
3646     // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3647     // It is done after compilers are initialized, because otherwise compilations of
3648     // signature polymorphic MH intrinsics can be missed
3649     // (see SystemDictionary::find_method_handle_intrinsic).
3650     initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3651     initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3652     initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3653   }
3654 
3655 #if INCLUDE_MANAGEMENT
3656   Management::initialize(THREAD);
3657 #endif // INCLUDE_MANAGEMENT
3658 
3659   if (HAS_PENDING_EXCEPTION) {
3660     // management agent fails to start possibly due to
3661     // configuration problem and is responsible for printing
3662     // stack trace if appropriate. Simply exit VM.
3663     vm_exit(1);
3664   }
3665 
3666   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3667   if (MemProfiling)                   MemProfiler::engage();
3668   StatSampler::engage();
3669   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3670 
3671   BiasedLocking::init();
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   // Give os specific code one last chance to start
3697   os::init_3();
3698 
3699   create_vm_timer.end();
3700 #ifdef ASSERT
3701   _vm_complete = true;
3702 #endif
3703   return JNI_OK;
3704 }
3705 
3706 // type for the Agent_OnLoad and JVM_OnLoad entry points
3707 extern "C" {
3708   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3709 }
3710 // Find a command line agent library and return its entry point for
3711 //         -agentlib:  -agentpath:   -Xrun
3712 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3713 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3714   OnLoadEntry_t on_load_entry = NULL;
3715   void *library = NULL;
3716 
3717   if (!agent->valid()) {
3718     char buffer[JVM_MAXPATHLEN];
3719     char ebuf[1024];
3720     const char *name = agent->name();
3721     const char *msg = "Could not find agent library ";
3722 
3723     // First check to see if agent is statically linked into executable
3724     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3725       library = agent->os_lib();
3726     } else if (agent->is_absolute_path()) {
3727       library = os::dll_load(name, ebuf, sizeof ebuf);
3728       if (library == NULL) {
3729         const char *sub_msg = " in absolute path, with error: ";
3730         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3731         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3732         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3733         // If we can't find the agent, exit.
3734         vm_exit_during_initialization(buf, NULL);
3735         FREE_C_HEAP_ARRAY(char, buf, mtThread);
3736       }
3737     } else {
3738       // Try to load the agent from the standard dll directory
3739       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3740                              name)) {
3741         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3742       }
3743       if (library == NULL) { // Try the local directory
3744         char ns[1] = {0};
3745         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3746           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3747         }
3748         if (library == NULL) {
3749           const char *sub_msg = " on the library path, with error: ";
3750           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3751           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3752           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3753           // If we can't find the agent, exit.
3754           vm_exit_during_initialization(buf, NULL);
3755           FREE_C_HEAP_ARRAY(char, buf, mtThread);
3756         }
3757       }
3758     }
3759     agent->set_os_lib(library);
3760     agent->set_valid();
3761   }
3762 
3763   // Find the OnLoad function.
3764   on_load_entry =
3765     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3766                                                           false,
3767                                                           on_load_symbols,
3768                                                           num_symbol_entries));
3769   return on_load_entry;
3770 }
3771 
3772 // Find the JVM_OnLoad entry point
3773 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3774   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3775   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3776 }
3777 
3778 // Find the Agent_OnLoad entry point
3779 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3780   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3781   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3782 }
3783 
3784 // For backwards compatibility with -Xrun
3785 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3786 // treated like -agentpath:
3787 // Must be called before agent libraries are created
3788 void Threads::convert_vm_init_libraries_to_agents() {
3789   AgentLibrary* agent;
3790   AgentLibrary* next;
3791 
3792   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3793     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3794     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3795 
3796     // If there is an JVM_OnLoad function it will get called later,
3797     // otherwise see if there is an Agent_OnLoad
3798     if (on_load_entry == NULL) {
3799       on_load_entry = lookup_agent_on_load(agent);
3800       if (on_load_entry != NULL) {
3801         // switch it to the agent list -- so that Agent_OnLoad will be called,
3802         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3803         Arguments::convert_library_to_agent(agent);
3804       } else {
3805         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3806       }
3807     }
3808   }
3809 }
3810 
3811 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3812 // Invokes Agent_OnLoad
3813 // Called very early -- before JavaThreads exist
3814 void Threads::create_vm_init_agents() {
3815   extern struct JavaVM_ main_vm;
3816   AgentLibrary* agent;
3817 
3818   JvmtiExport::enter_onload_phase();
3819 
3820   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3821     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3822 
3823     if (on_load_entry != NULL) {
3824       // Invoke the Agent_OnLoad function
3825       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3826       if (err != JNI_OK) {
3827         vm_exit_during_initialization("agent library failed to init", agent->name());
3828       }
3829     } else {
3830       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3831     }
3832   }
3833   JvmtiExport::enter_primordial_phase();
3834 }
3835 
3836 extern "C" {
3837   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3838 }
3839 
3840 void Threads::shutdown_vm_agents() {
3841   // Send any Agent_OnUnload notifications
3842   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3843   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3844   extern struct JavaVM_ main_vm;
3845   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3846 
3847     // Find the Agent_OnUnload function.
3848     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3849       os::find_agent_function(agent,
3850       false,
3851       on_unload_symbols,
3852       num_symbol_entries));
3853 
3854     // Invoke the Agent_OnUnload function
3855     if (unload_entry != NULL) {
3856       JavaThread* thread = JavaThread::current();
3857       ThreadToNativeFromVM ttn(thread);
3858       HandleMark hm(thread);
3859       (*unload_entry)(&main_vm);
3860     }
3861   }
3862 }
3863 
3864 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3865 // Invokes JVM_OnLoad
3866 void Threads::create_vm_init_libraries() {
3867   extern struct JavaVM_ main_vm;
3868   AgentLibrary* agent;
3869 
3870   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3871     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3872 
3873     if (on_load_entry != NULL) {
3874       // Invoke the JVM_OnLoad function
3875       JavaThread* thread = JavaThread::current();
3876       ThreadToNativeFromVM ttn(thread);
3877       HandleMark hm(thread);
3878       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3879       if (err != JNI_OK) {
3880         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3881       }
3882     } else {
3883       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3884     }
3885   }
3886 }
3887 
3888 // Last thread running calls java.lang.Shutdown.shutdown()
3889 void JavaThread::invoke_shutdown_hooks() {
3890   HandleMark hm(this);
3891 
3892   // We could get here with a pending exception, if so clear it now.
3893   if (this->has_pending_exception()) {
3894     this->clear_pending_exception();
3895   }
3896 
3897   EXCEPTION_MARK;
3898   Klass* k =
3899     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3900                                       THREAD);
3901   if (k != NULL) {
3902     // SystemDictionary::resolve_or_null will return null if there was
3903     // an exception.  If we cannot load the Shutdown class, just don't
3904     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3905     // and finalizers (if runFinalizersOnExit is set) won't be run.
3906     // Note that if a shutdown hook was registered or runFinalizersOnExit
3907     // was called, the Shutdown class would have already been loaded
3908     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3909     instanceKlassHandle shutdown_klass (THREAD, k);
3910     JavaValue result(T_VOID);
3911     JavaCalls::call_static(&result,
3912                            shutdown_klass,
3913                            vmSymbols::shutdown_method_name(),
3914                            vmSymbols::void_method_signature(),
3915                            THREAD);
3916   }
3917   CLEAR_PENDING_EXCEPTION;
3918 }
3919 
3920 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3921 // the program falls off the end of main(). Another VM exit path is through
3922 // vm_exit() when the program calls System.exit() to return a value or when
3923 // there is a serious error in VM. The two shutdown paths are not exactly
3924 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3925 // and VM_Exit op at VM level.
3926 //
3927 // Shutdown sequence:
3928 //   + Shutdown native memory tracking if it is on
3929 //   + Wait until we are the last non-daemon thread to execute
3930 //     <-- every thing is still working at this moment -->
3931 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3932 //        shutdown hooks, run finalizers if finalization-on-exit
3933 //   + Call before_exit(), prepare for VM exit
3934 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3935 //        currently the only user of this mechanism is File.deleteOnExit())
3936 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3937 //        post thread end and vm death events to JVMTI,
3938 //        stop signal thread
3939 //   + Call JavaThread::exit(), it will:
3940 //      > release JNI handle blocks, remove stack guard pages
3941 //      > remove this thread from Threads list
3942 //     <-- no more Java code from this thread after this point -->
3943 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3944 //     the compiler threads at safepoint
3945 //     <-- do not use anything that could get blocked by Safepoint -->
3946 //   + Disable tracing at JNI/JVM barriers
3947 //   + Set _vm_exited flag for threads that are still running native code
3948 //   + Delete this thread
3949 //   + Call exit_globals()
3950 //      > deletes tty
3951 //      > deletes PerfMemory resources
3952 //   + Return to caller
3953 
3954 bool Threads::destroy_vm() {
3955   JavaThread* thread = JavaThread::current();
3956 
3957 #ifdef ASSERT
3958   _vm_complete = false;
3959 #endif
3960   // Wait until we are the last non-daemon thread to execute
3961   { MutexLocker nu(Threads_lock);
3962     while (Threads::number_of_non_daemon_threads() > 1 )
3963       // This wait should make safepoint checks, wait without a timeout,
3964       // and wait as a suspend-equivalent condition.
3965       //
3966       // Note: If the FlatProfiler is running and this thread is waiting
3967       // for another non-daemon thread to finish, then the FlatProfiler
3968       // is waiting for the external suspend request on this thread to
3969       // complete. wait_for_ext_suspend_completion() will eventually
3970       // timeout, but that takes time. Making this wait a suspend-
3971       // equivalent condition solves that timeout problem.
3972       //
3973       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3974                          Mutex::_as_suspend_equivalent_flag);
3975   }
3976 
3977   // Hang forever on exit if we are reporting an error.
3978   if (ShowMessageBoxOnError && is_error_reported()) {
3979     os::infinite_sleep();
3980   }
3981   os::wait_for_keypress_at_exit();
3982 
3983   if (JDK_Version::is_jdk12x_version()) {
3984     // We are the last thread running, so check if finalizers should be run.
3985     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3986     HandleMark rm(thread);
3987     Universe::run_finalizers_on_exit();
3988   } else {
3989     // run Java level shutdown hooks
3990     thread->invoke_shutdown_hooks();
3991   }
3992 
3993   before_exit(thread);
3994 
3995   thread->exit(true);
3996 
3997   // Stop VM thread.
3998   {
3999     // 4945125 The vm thread comes to a safepoint during exit.
4000     // GC vm_operations can get caught at the safepoint, and the
4001     // heap is unparseable if they are caught. Grab the Heap_lock
4002     // to prevent this. The GC vm_operations will not be able to
4003     // queue until after the vm thread is dead.
4004     // After this point, we'll never emerge out of the safepoint before
4005     // the VM exits, so concurrent GC threads do not need to be explicitly
4006     // stopped; they remain inactive until the process exits.
4007     // Note: some concurrent G1 threads may be running during a safepoint,
4008     // but these will not be accessing the heap, just some G1-specific side
4009     // data structures that are not accessed by any other threads but them
4010     // after this point in a terminal safepoint.
4011 
4012     MutexLocker ml(Heap_lock);
4013 
4014     VMThread::wait_for_vm_thread_exit();
4015     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4016     VMThread::destroy();
4017   }
4018 
4019   // clean up ideal graph printers
4020 #if defined(COMPILER2) && !defined(PRODUCT)
4021   IdealGraphPrinter::clean_up();
4022 #endif
4023 
4024   // Now, all Java threads are gone except daemon threads. Daemon threads
4025   // running Java code or in VM are stopped by the Safepoint. However,
4026   // daemon threads executing native code are still running.  But they
4027   // will be stopped at native=>Java/VM barriers. Note that we can't
4028   // simply kill or suspend them, as it is inherently deadlock-prone.
4029 
4030 #ifndef PRODUCT
4031   // disable function tracing at JNI/JVM barriers
4032   TraceJNICalls = false;
4033   TraceJVMCalls = false;
4034   TraceRuntimeCalls = false;
4035 #endif
4036 
4037   VM_Exit::set_vm_exited();
4038 
4039   notify_vm_shutdown();
4040 
4041   delete thread;
4042 
4043   // exit_globals() will delete tty
4044   exit_globals();
4045 
4046   return true;
4047 }
4048 
4049 
4050 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4051   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4052   return is_supported_jni_version(version);
4053 }
4054 
4055 
4056 jboolean Threads::is_supported_jni_version(jint version) {
4057   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4058   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4059   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4060   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4061   return JNI_FALSE;
4062 }
4063 
4064 
4065 void Threads::add(JavaThread* p, bool force_daemon) {
4066   // The threads lock must be owned at this point
4067   assert_locked_or_safepoint(Threads_lock);
4068 
4069   // See the comment for this method in thread.hpp for its purpose and
4070   // why it is called here.
4071   p->initialize_queues();
4072   p->set_next(_thread_list);
4073   _thread_list = p;
4074   _number_of_threads++;
4075   oop threadObj = p->threadObj();
4076   bool daemon = true;
4077   // Bootstrapping problem: threadObj can be null for initial
4078   // JavaThread (or for threads attached via JNI)
4079   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4080     _number_of_non_daemon_threads++;
4081     daemon = false;
4082   }
4083 
4084   p->set_safepoint_visible(true);
4085 
4086   ThreadService::add_thread(p, daemon);
4087 
4088   // Possible GC point.
4089   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4090 }
4091 
4092 void Threads::remove(JavaThread* p) {
4093   // Extra scope needed for Thread_lock, so we can check
4094   // that we do not remove thread without safepoint code notice
4095   { MutexLocker ml(Threads_lock);
4096 
4097     assert(includes(p), "p must be present");
4098 
4099     JavaThread* current = _thread_list;
4100     JavaThread* prev    = NULL;
4101 
4102     while (current != p) {
4103       prev    = current;
4104       current = current->next();
4105     }
4106 
4107     if (prev) {
4108       prev->set_next(current->next());
4109     } else {
4110       _thread_list = p->next();
4111     }
4112     _number_of_threads--;
4113     oop threadObj = p->threadObj();
4114     bool daemon = true;
4115     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4116       _number_of_non_daemon_threads--;
4117       daemon = false;
4118 
4119       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4120       // on destroy_vm will wake up.
4121       if (number_of_non_daemon_threads() == 1)
4122         Threads_lock->notify_all();
4123     }
4124     ThreadService::remove_thread(p, daemon);
4125 
4126     // Make sure that safepoint code disregard this thread. This is needed since
4127     // the thread might mess around with locks after this point. This can cause it
4128     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4129     // of this thread since it is removed from the queue.
4130     p->set_terminated_value();
4131 
4132     // Now, this thread is not visible to safepoint
4133     p->set_safepoint_visible(false);
4134     // once the thread becomes safepoint invisible, we can not use its per-thread
4135     // recorder. And Threads::do_threads() no longer walks this thread, so we have
4136     // to release its per-thread recorder here.
4137     MemTracker::thread_exiting(p);
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 guarantee this property. It also makes sure that
4160 // all threads gets blocked when exiting or starting).
4161 
4162 void Threads::oops_do(OopClosure* f, CLDToOopClosure* 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, CLDToOopClosure* 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_strong_roots().  n_par_threads == 0 will
4177   // turn off parallelism in process_strong_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(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              // Consider using a simple NakedSleep() instead.
4450              // Then SpinAcquire could be called by non-JVM threads
4451              Thread::current()->_ParkEvent->park(1) ;
4452            } else {
4453              os::NakedYield() ;
4454              ++Yields ;
4455            }
4456         } else {
4457            SpinPause() ;
4458         }
4459      }
4460      if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4461   }
4462 }
4463 
4464 void Thread::SpinRelease (volatile int * adr) {
4465   assert (*adr != 0, "invariant") ;
4466   OrderAccess::fence() ;      // guarantee at least release consistency.
4467   // Roach-motel semantics.
4468   // It's safe if subsequent LDs and STs float "up" into the critical section,
4469   // but prior LDs and STs within the critical section can't be allowed
4470   // to reorder or float past the ST that releases the lock.
4471   *adr = 0 ;
4472 }
4473 
4474 // muxAcquire and muxRelease:
4475 //
4476 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4477 //    The LSB of the word is set IFF the lock is held.
4478 //    The remainder of the word points to the head of a singly-linked list
4479 //    of threads blocked on the lock.
4480 //
4481 // *  The current implementation of muxAcquire-muxRelease uses its own
4482 //    dedicated Thread._MuxEvent instance.  If we're interested in
4483 //    minimizing the peak number of extant ParkEvent instances then
4484 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4485 //    as certain invariants were satisfied.  Specifically, care would need
4486 //    to be taken with regards to consuming unpark() "permits".
4487 //    A safe rule of thumb is that a thread would never call muxAcquire()
4488 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4489 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4490 //    consume an unpark() permit intended for monitorenter, for instance.
4491 //    One way around this would be to widen the restricted-range semaphore
4492 //    implemented in park().  Another alternative would be to provide
4493 //    multiple instances of the PlatformEvent() for each thread.  One
4494 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4495 //
4496 // *  Usage:
4497 //    -- Only as leaf locks
4498 //    -- for short-term locking only as muxAcquire does not perform
4499 //       thread state transitions.
4500 //
4501 // Alternatives:
4502 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4503 //    but with parking or spin-then-park instead of pure spinning.
4504 // *  Use Taura-Oyama-Yonenzawa locks.
4505 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4506 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4507 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4508 //    acquiring threads use timers (ParkTimed) to detect and recover from
4509 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4510 //    boundaries by using placement-new.
4511 // *  Augment MCS with advisory back-link fields maintained with CAS().
4512 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4513 //    The validity of the backlinks must be ratified before we trust the value.
4514 //    If the backlinks are invalid the exiting thread must back-track through the
4515 //    the forward links, which are always trustworthy.
4516 // *  Add a successor indication.  The LockWord is currently encoded as
4517 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4518 //    to provide the usual futile-wakeup optimization.
4519 //    See RTStt for details.
4520 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4521 //
4522 
4523 
4524 typedef volatile intptr_t MutexT ;      // Mux Lock-word
4525 enum MuxBits { LOCKBIT = 1 } ;
4526 
4527 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4528   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4529   if (w == 0) return ;
4530   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4531      return ;
4532   }
4533 
4534   TEVENT (muxAcquire - Contention) ;
4535   ParkEvent * const Self = Thread::current()->_MuxEvent ;
4536   assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4537   for (;;) {
4538      int its = (os::is_MP() ? 100 : 0) + 1 ;
4539 
4540      // Optional spin phase: spin-then-park strategy
4541      while (--its >= 0) {
4542        w = *Lock ;
4543        if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4544           return ;
4545        }
4546      }
4547 
4548      Self->reset() ;
4549      Self->OnList = intptr_t(Lock) ;
4550      // The following fence() isn't _strictly necessary as the subsequent
4551      // CAS() both serializes execution and ratifies the fetched *Lock value.
4552      OrderAccess::fence();
4553      for (;;) {
4554         w = *Lock ;
4555         if ((w & LOCKBIT) == 0) {
4556             if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4557                 Self->OnList = 0 ;   // hygiene - allows stronger asserts
4558                 return ;
4559             }
4560             continue ;      // Interference -- *Lock changed -- Just retry
4561         }
4562         assert (w & LOCKBIT, "invariant") ;
4563         Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4564         if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4565      }
4566 
4567      while (Self->OnList != 0) {
4568         Self->park() ;
4569      }
4570   }
4571 }
4572 
4573 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4574   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4575   if (w == 0) return ;
4576   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4577     return ;
4578   }
4579 
4580   TEVENT (muxAcquire - Contention) ;
4581   ParkEvent * ReleaseAfter = NULL ;
4582   if (ev == NULL) {
4583     ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4584   }
4585   assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4586   for (;;) {
4587     guarantee (ev->OnList == 0, "invariant") ;
4588     int its = (os::is_MP() ? 100 : 0) + 1 ;
4589 
4590     // Optional spin phase: spin-then-park strategy
4591     while (--its >= 0) {
4592       w = *Lock ;
4593       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4594         if (ReleaseAfter != NULL) {
4595           ParkEvent::Release (ReleaseAfter) ;
4596         }
4597         return ;
4598       }
4599     }
4600 
4601     ev->reset() ;
4602     ev->OnList = intptr_t(Lock) ;
4603     // The following fence() isn't _strictly necessary as the subsequent
4604     // CAS() both serializes execution and ratifies the fetched *Lock value.
4605     OrderAccess::fence();
4606     for (;;) {
4607       w = *Lock ;
4608       if ((w & LOCKBIT) == 0) {
4609         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4610           ev->OnList = 0 ;
4611           // We call ::Release while holding the outer lock, thus
4612           // artificially lengthening the critical section.
4613           // Consider deferring the ::Release() until the subsequent unlock(),
4614           // after we've dropped the outer lock.
4615           if (ReleaseAfter != NULL) {
4616             ParkEvent::Release (ReleaseAfter) ;
4617           }
4618           return ;
4619         }
4620         continue ;      // Interference -- *Lock changed -- Just retry
4621       }
4622       assert (w & LOCKBIT, "invariant") ;
4623       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4624       if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4625     }
4626 
4627     while (ev->OnList != 0) {
4628       ev->park() ;
4629     }
4630   }
4631 }
4632 
4633 // Release() must extract a successor from the list and then wake that thread.
4634 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4635 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4636 // Release() would :
4637 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4638 // (B) Extract a successor from the private list "in-hand"
4639 // (C) attempt to CAS() the residual back into *Lock over null.
4640 //     If there were any newly arrived threads and the CAS() would fail.
4641 //     In that case Release() would detach the RATs, re-merge the list in-hand
4642 //     with the RATs and repeat as needed.  Alternately, Release() might
4643 //     detach and extract a successor, but then pass the residual list to the wakee.
4644 //     The wakee would be responsible for reattaching and remerging before it
4645 //     competed for the lock.
4646 //
4647 // Both "pop" and DMR are immune from ABA corruption -- there can be
4648 // multiple concurrent pushers, but only one popper or detacher.
4649 // This implementation pops from the head of the list.  This is unfair,
4650 // but tends to provide excellent throughput as hot threads remain hot.
4651 // (We wake recently run threads first).
4652 
4653 void Thread::muxRelease (volatile intptr_t * Lock)  {
4654   for (;;) {
4655     const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4656     assert (w & LOCKBIT, "invariant") ;
4657     if (w == LOCKBIT) return ;
4658     ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4659     assert (List != NULL, "invariant") ;
4660     assert (List->OnList == intptr_t(Lock), "invariant") ;
4661     ParkEvent * nxt = List->ListNext ;
4662 
4663     // The following CAS() releases the lock and pops the head element.
4664     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4665       continue ;
4666     }
4667     List->OnList = 0 ;
4668     OrderAccess::fence() ;
4669     List->unpark () ;
4670     return ;
4671   }
4672 }
4673 
4674 
4675 void Threads::verify() {
4676   ALL_JAVA_THREADS(p) {
4677     p->verify();
4678   }
4679   VMThread* thread = VMThread::vm_thread();
4680   if (thread != NULL) thread->verify();
4681 }