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   // stack_base can be NULL if the thread is never started or exited before
 337   // record_stack_base_and_size called. Although, we would like to ensure
 338   // that all started threads do call record_stack_base_and_size(), there is
 339   // not proper way to enforce that.
 340 #if INCLUDE_NMT
 341   if (_stack_base != NULL) {
 342     address low_stack_addr = stack_base() - stack_size();
 343     MemTracker::release_thread_stack(low_stack_addr, stack_size(), this);
 344 #ifdef ASSERT
 345     set_stack_base(NULL);
 346 #endif
 347   }
 348 #endif // INCLUDE_NMT
 349 
 350   // deallocate data structures
 351   delete resource_area();
 352   // since the handle marks are using the handle area, we have to deallocated the root
 353   // handle mark before deallocating the thread's handle area,
 354   assert(last_handle_mark() != NULL, "check we have an element");
 355   delete last_handle_mark();
 356   assert(last_handle_mark() == NULL, "check we have reached the end");
 357 
 358   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 359   // We NULL out the fields for good hygiene.
 360   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 361   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 362   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 363   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 364 
 365   delete handle_area();
 366   delete metadata_handles();
 367 
 368   // osthread() can be NULL, if creation of thread failed.
 369   if (osthread() != NULL) os::free_thread(osthread());
 370 
 371   delete _SR_lock;
 372 
 373   // clear thread local storage if the Thread is deleting itself
 374   if (this == Thread::current()) {
 375     ThreadLocalStorage::set_thread(NULL);
 376   } else {
 377     // In the case where we're not the current thread, invalidate all the
 378     // caches in case some code tries to get the current thread or the
 379     // thread that was destroyed, and gets stale information.
 380     ThreadLocalStorage::invalidate_all();
 381   }
 382   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 383 }
 384 
 385 // NOTE: dummy function for assertion purpose.
 386 void Thread::run() {
 387   ShouldNotReachHere();
 388 }
 389 
 390 #ifdef ASSERT
 391 // Private method to check for dangling thread pointer
 392 void check_for_dangling_thread_pointer(Thread *thread) {
 393  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 394          "possibility of dangling Thread pointer");
 395 }
 396 #endif
 397 
 398 
 399 #ifndef PRODUCT
 400 // Tracing method for basic thread operations
 401 void Thread::trace(const char* msg, const Thread* const thread) {
 402   if (!TraceThreadEvents) return;
 403   ResourceMark rm;
 404   ThreadCritical tc;
 405   const char *name = "non-Java thread";
 406   int prio = -1;
 407   if (thread->is_Java_thread()
 408       && !thread->is_Compiler_thread()) {
 409     // The Threads_lock must be held to get information about
 410     // this thread but may not be in some situations when
 411     // tracing  thread events.
 412     bool release_Threads_lock = false;
 413     if (!Threads_lock->owned_by_self()) {
 414       Threads_lock->lock();
 415       release_Threads_lock = true;
 416     }
 417     JavaThread* jt = (JavaThread *)thread;
 418     name = (char *)jt->get_thread_name();
 419     oop thread_oop = jt->threadObj();
 420     if (thread_oop != NULL) {
 421       prio = java_lang_Thread::priority(thread_oop);
 422     }
 423     if (release_Threads_lock) {
 424       Threads_lock->unlock();
 425     }
 426   }
 427   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 428 }
 429 #endif
 430 
 431 
 432 ThreadPriority Thread::get_priority(const Thread* const thread) {
 433   trace("get priority", thread);
 434   ThreadPriority priority;
 435   // Can return an error!
 436   (void)os::get_priority(thread, priority);
 437   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 438   return priority;
 439 }
 440 
 441 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 442   trace("set priority", thread);
 443   debug_only(check_for_dangling_thread_pointer(thread);)
 444   // Can return an error!
 445   (void)os::set_priority(thread, priority);
 446 }
 447 
 448 
 449 void Thread::start(Thread* thread) {
 450   trace("start", thread);
 451   // Start is different from resume in that its safety is guaranteed by context or
 452   // being called from a Java method synchronized on the Thread object.
 453   if (!DisableStartThread) {
 454     if (thread->is_Java_thread()) {
 455       // Initialize the thread state to RUNNABLE before starting this thread.
 456       // Can not set it after the thread started because we do not know the
 457       // exact thread state at that time. It could be in MONITOR_WAIT or
 458       // in SLEEPING or some other state.
 459       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 460                                           java_lang_Thread::RUNNABLE);
 461     }
 462     os::start_thread(thread);
 463   }
 464 }
 465 
 466 // Enqueue a VM_Operation to do the job for us - sometime later
 467 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 468   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 469   VMThread::execute(vm_stop);
 470 }
 471 
 472 
 473 //
 474 // Check if an external suspend request has completed (or has been
 475 // cancelled). Returns true if the thread is externally suspended and
 476 // false otherwise.
 477 //
 478 // The bits parameter returns information about the code path through
 479 // the routine. Useful for debugging:
 480 //
 481 // set in is_ext_suspend_completed():
 482 // 0x00000001 - routine was entered
 483 // 0x00000010 - routine return false at end
 484 // 0x00000100 - thread exited (return false)
 485 // 0x00000200 - suspend request cancelled (return false)
 486 // 0x00000400 - thread suspended (return true)
 487 // 0x00001000 - thread is in a suspend equivalent state (return true)
 488 // 0x00002000 - thread is native and walkable (return true)
 489 // 0x00004000 - thread is native_trans and walkable (needed retry)
 490 //
 491 // set in wait_for_ext_suspend_completion():
 492 // 0x00010000 - routine was entered
 493 // 0x00020000 - suspend request cancelled before loop (return false)
 494 // 0x00040000 - thread suspended before loop (return true)
 495 // 0x00080000 - suspend request cancelled in loop (return false)
 496 // 0x00100000 - thread suspended in loop (return true)
 497 // 0x00200000 - suspend not completed during retry loop (return false)
 498 //
 499 
 500 // Helper class for tracing suspend wait debug bits.
 501 //
 502 // 0x00000100 indicates that the target thread exited before it could
 503 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 504 // 0x00080000 each indicate a cancelled suspend request so they don't
 505 // count as wait failures either.
 506 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 507 
 508 class TraceSuspendDebugBits : public StackObj {
 509  private:
 510   JavaThread * jt;
 511   bool         is_wait;
 512   bool         called_by_wait;  // meaningful when !is_wait
 513   uint32_t *   bits;
 514 
 515  public:
 516   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 517                         uint32_t *_bits) {
 518     jt             = _jt;
 519     is_wait        = _is_wait;
 520     called_by_wait = _called_by_wait;
 521     bits           = _bits;
 522   }
 523 
 524   ~TraceSuspendDebugBits() {
 525     if (!is_wait) {
 526 #if 1
 527       // By default, don't trace bits for is_ext_suspend_completed() calls.
 528       // That trace is very chatty.
 529       return;
 530 #else
 531       if (!called_by_wait) {
 532         // If tracing for is_ext_suspend_completed() is enabled, then only
 533         // trace calls to it from wait_for_ext_suspend_completion()
 534         return;
 535       }
 536 #endif
 537     }
 538 
 539     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 540       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 541         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 542         ResourceMark rm;
 543 
 544         tty->print_cr(
 545             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 546             jt->get_thread_name(), *bits);
 547 
 548         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 549       }
 550     }
 551   }
 552 };
 553 #undef DEBUG_FALSE_BITS
 554 
 555 
 556 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 557   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 558 
 559   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 560   bool do_trans_retry;           // flag to force the retry
 561 
 562   *bits |= 0x00000001;
 563 
 564   do {
 565     do_trans_retry = false;
 566 
 567     if (is_exiting()) {
 568       // Thread is in the process of exiting. This is always checked
 569       // first to reduce the risk of dereferencing a freed JavaThread.
 570       *bits |= 0x00000100;
 571       return false;
 572     }
 573 
 574     if (!is_external_suspend()) {
 575       // Suspend request is cancelled. This is always checked before
 576       // is_ext_suspended() to reduce the risk of a rogue resume
 577       // confusing the thread that made the suspend request.
 578       *bits |= 0x00000200;
 579       return false;
 580     }
 581 
 582     if (is_ext_suspended()) {
 583       // thread is suspended
 584       *bits |= 0x00000400;
 585       return true;
 586     }
 587 
 588     // Now that we no longer do hard suspends of threads running
 589     // native code, the target thread can be changing thread state
 590     // while we are in this routine:
 591     //
 592     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 593     //
 594     // We save a copy of the thread state as observed at this moment
 595     // and make our decision about suspend completeness based on the
 596     // copy. This closes the race where the thread state is seen as
 597     // _thread_in_native_trans in the if-thread_blocked check, but is
 598     // seen as _thread_blocked in if-thread_in_native_trans check.
 599     JavaThreadState save_state = thread_state();
 600 
 601     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 602       // If the thread's state is _thread_blocked and this blocking
 603       // condition is known to be equivalent to a suspend, then we can
 604       // consider the thread to be externally suspended. This means that
 605       // the code that sets _thread_blocked has been modified to do
 606       // self-suspension if the blocking condition releases. We also
 607       // used to check for CONDVAR_WAIT here, but that is now covered by
 608       // the _thread_blocked with self-suspension check.
 609       //
 610       // Return true since we wouldn't be here unless there was still an
 611       // external suspend request.
 612       *bits |= 0x00001000;
 613       return true;
 614     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 615       // Threads running native code will self-suspend on native==>VM/Java
 616       // transitions. If its stack is walkable (should always be the case
 617       // unless this function is called before the actual java_suspend()
 618       // call), then the wait is done.
 619       *bits |= 0x00002000;
 620       return true;
 621     } else if (!called_by_wait && !did_trans_retry &&
 622                save_state == _thread_in_native_trans &&
 623                frame_anchor()->walkable()) {
 624       // The thread is transitioning from thread_in_native to another
 625       // thread state. check_safepoint_and_suspend_for_native_trans()
 626       // will force the thread to self-suspend. If it hasn't gotten
 627       // there yet we may have caught the thread in-between the native
 628       // code check above and the self-suspend. Lucky us. If we were
 629       // called by wait_for_ext_suspend_completion(), then it
 630       // will be doing the retries so we don't have to.
 631       //
 632       // Since we use the saved thread state in the if-statement above,
 633       // there is a chance that the thread has already transitioned to
 634       // _thread_blocked by the time we get here. In that case, we will
 635       // make a single unnecessary pass through the logic below. This
 636       // doesn't hurt anything since we still do the trans retry.
 637 
 638       *bits |= 0x00004000;
 639 
 640       // Once the thread leaves thread_in_native_trans for another
 641       // thread state, we break out of this retry loop. We shouldn't
 642       // need this flag to prevent us from getting back here, but
 643       // sometimes paranoia is good.
 644       did_trans_retry = true;
 645 
 646       // We wait for the thread to transition to a more usable state.
 647       for (int i = 1; i <= SuspendRetryCount; i++) {
 648         // We used to do an "os::yield_all(i)" call here with the intention
 649         // that yielding would increase on each retry. However, the parameter
 650         // is ignored on Linux which means the yield didn't scale up. Waiting
 651         // on the SR_lock below provides a much more predictable scale up for
 652         // the delay. It also provides a simple/direct point to check for any
 653         // safepoint requests from the VMThread
 654 
 655         // temporarily drops SR_lock while doing wait with safepoint check
 656         // (if we're a JavaThread - the WatcherThread can also call this)
 657         // and increase delay with each retry
 658         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 659 
 660         // check the actual thread state instead of what we saved above
 661         if (thread_state() != _thread_in_native_trans) {
 662           // the thread has transitioned to another thread state so
 663           // try all the checks (except this one) one more time.
 664           do_trans_retry = true;
 665           break;
 666         }
 667       } // end retry loop
 668 
 669 
 670     }
 671   } while (do_trans_retry);
 672 
 673   *bits |= 0x00000010;
 674   return false;
 675 }
 676 
 677 //
 678 // Wait for an external suspend request to complete (or be cancelled).
 679 // Returns true if the thread is externally suspended and false otherwise.
 680 //
 681 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 682        uint32_t *bits) {
 683   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 684                              false /* !called_by_wait */, bits);
 685 
 686   // local flag copies to minimize SR_lock hold time
 687   bool is_suspended;
 688   bool pending;
 689   uint32_t reset_bits;
 690 
 691   // set a marker so is_ext_suspend_completed() knows we are the caller
 692   *bits |= 0x00010000;
 693 
 694   // We use reset_bits to reinitialize the bits value at the top of
 695   // each retry loop. This allows the caller to make use of any
 696   // unused bits for their own marking purposes.
 697   reset_bits = *bits;
 698 
 699   {
 700     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 701     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 702                                             delay, bits);
 703     pending = is_external_suspend();
 704   }
 705   // must release SR_lock to allow suspension to complete
 706 
 707   if (!pending) {
 708     // A cancelled suspend request is the only false return from
 709     // is_ext_suspend_completed() that keeps us from entering the
 710     // retry loop.
 711     *bits |= 0x00020000;
 712     return false;
 713   }
 714 
 715   if (is_suspended) {
 716     *bits |= 0x00040000;
 717     return true;
 718   }
 719 
 720   for (int i = 1; i <= retries; i++) {
 721     *bits = reset_bits;  // reinit to only track last retry
 722 
 723     // We used to do an "os::yield_all(i)" call here with the intention
 724     // that yielding would increase on each retry. However, the parameter
 725     // is ignored on Linux which means the yield didn't scale up. Waiting
 726     // on the SR_lock below provides a much more predictable scale up for
 727     // the delay. It also provides a simple/direct point to check for any
 728     // safepoint requests from the VMThread
 729 
 730     {
 731       MutexLocker ml(SR_lock());
 732       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 733       // can also call this)  and increase delay with each retry
 734       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 735 
 736       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 737                                               delay, bits);
 738 
 739       // It is possible for the external suspend request to be cancelled
 740       // (by a resume) before the actual suspend operation is completed.
 741       // Refresh our local copy to see if we still need to wait.
 742       pending = is_external_suspend();
 743     }
 744 
 745     if (!pending) {
 746       // A cancelled suspend request is the only false return from
 747       // is_ext_suspend_completed() that keeps us from staying in the
 748       // retry loop.
 749       *bits |= 0x00080000;
 750       return false;
 751     }
 752 
 753     if (is_suspended) {
 754       *bits |= 0x00100000;
 755       return true;
 756     }
 757   } // end retry loop
 758 
 759   // thread did not suspend after all our retries
 760   *bits |= 0x00200000;
 761   return false;
 762 }
 763 
 764 #ifndef PRODUCT
 765 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 766 
 767   // This should not need to be atomic as the only way for simultaneous
 768   // updates is via interrupts. Even then this should be rare or non-existant
 769   // and we don't care that much anyway.
 770 
 771   int index = _jmp_ring_index;
 772   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 773   _jmp_ring[index]._target = (intptr_t) target;
 774   _jmp_ring[index]._instruction = (intptr_t) instr;
 775   _jmp_ring[index]._file = file;
 776   _jmp_ring[index]._line = line;
 777 }
 778 #endif /* PRODUCT */
 779 
 780 // Called by flat profiler
 781 // Callers have already called wait_for_ext_suspend_completion
 782 // The assertion for that is currently too complex to put here:
 783 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 784   bool gotframe = false;
 785   // self suspension saves needed state.
 786   if (has_last_Java_frame() && _anchor.walkable()) {
 787      *_fr = pd_last_frame();
 788      gotframe = true;
 789   }
 790   return gotframe;
 791 }
 792 
 793 void Thread::interrupt(Thread* thread) {
 794   trace("interrupt", thread);
 795   debug_only(check_for_dangling_thread_pointer(thread);)
 796   os::interrupt(thread);
 797 }
 798 
 799 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 800   trace("is_interrupted", thread);
 801   debug_only(check_for_dangling_thread_pointer(thread);)
 802   // Note:  If clear_interrupted==false, this simply fetches and
 803   // returns the value of the field osthread()->interrupted().
 804   return os::is_interrupted(thread, clear_interrupted);
 805 }
 806 
 807 
 808 // GC Support
 809 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 810   jint thread_parity = _oops_do_parity;
 811   if (thread_parity != strong_roots_parity) {
 812     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 813     if (res == thread_parity) {
 814       return true;
 815     } else {
 816       guarantee(res == strong_roots_parity, "Or else what?");
 817       assert(SharedHeap::heap()->workers()->active_workers() > 0,
 818          "Should only fail when parallel.");
 819       return false;
 820     }
 821   }
 822   assert(SharedHeap::heap()->workers()->active_workers() > 0,
 823          "Should only fail when parallel.");
 824   return false;
 825 }
 826 
 827 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
 828   active_handles()->oops_do(f);
 829   // Do oop for ThreadShadow
 830   f->do_oop((oop*)&_pending_exception);
 831   handle_area()->oops_do(f);
 832 }
 833 
 834 void Thread::nmethods_do(CodeBlobClosure* cf) {
 835   // no nmethods in a generic thread...
 836 }
 837 
 838 void Thread::metadata_do(void f(Metadata*)) {
 839   if (metadata_handles() != NULL) {
 840     for (int i = 0; i< metadata_handles()->length(); i++) {
 841       f(metadata_handles()->at(i));
 842     }
 843   }
 844 }
 845 
 846 void Thread::print_on(outputStream* st) const {
 847   // get_priority assumes osthread initialized
 848   if (osthread() != NULL) {
 849     int os_prio;
 850     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 851       st->print("os_prio=%d ", os_prio);
 852     }
 853     st->print("tid=" INTPTR_FORMAT " ", this);
 854     osthread()->print_on(st);
 855   }
 856   debug_only(if (WizardMode) print_owned_locks_on(st);)
 857 }
 858 
 859 // Thread::print_on_error() is called by fatal error handler. Don't use
 860 // any lock or allocate memory.
 861 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 862   if      (is_VM_thread())                  st->print("VMThread");
 863   else if (is_Compiler_thread())            st->print("CompilerThread");
 864   else if (is_Java_thread())                st->print("JavaThread");
 865   else if (is_GC_task_thread())             st->print("GCTaskThread");
 866   else if (is_Watcher_thread())             st->print("WatcherThread");
 867   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 868   else st->print("Thread");
 869 
 870   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 871             _stack_base - _stack_size, _stack_base);
 872 
 873   if (osthread()) {
 874     st->print(" [id=%d]", osthread()->thread_id());
 875   }
 876 }
 877 
 878 #ifdef ASSERT
 879 void Thread::print_owned_locks_on(outputStream* st) const {
 880   Monitor *cur = _owned_locks;
 881   if (cur == NULL) {
 882     st->print(" (no locks) ");
 883   } else {
 884     st->print_cr(" Locks owned:");
 885     while(cur) {
 886       cur->print_on(st);
 887       cur = cur->next();
 888     }
 889   }
 890 }
 891 
 892 static int ref_use_count  = 0;
 893 
 894 bool Thread::owns_locks_but_compiled_lock() const {
 895   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 896     if (cur != Compile_lock) return true;
 897   }
 898   return false;
 899 }
 900 
 901 
 902 #endif
 903 
 904 #ifndef PRODUCT
 905 
 906 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 907 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 908 // no threads which allow_vm_block's are held
 909 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 910     // Check if current thread is allowed to block at a safepoint
 911     if (!(_allow_safepoint_count == 0))
 912       fatal("Possible safepoint reached by thread that does not allow it");
 913     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 914       fatal("LEAF method calling lock?");
 915     }
 916 
 917 #ifdef ASSERT
 918     if (potential_vm_operation && is_Java_thread()
 919         && !Universe::is_bootstrapping()) {
 920       // Make sure we do not hold any locks that the VM thread also uses.
 921       // This could potentially lead to deadlocks
 922       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 923         // Threads_lock is special, since the safepoint synchronization will not start before this is
 924         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 925         // since it is used to transfer control between JavaThreads and the VMThread
 926         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
 927         if ( (cur->allow_vm_block() &&
 928               cur != Threads_lock &&
 929               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
 930               cur != VMOperationRequest_lock &&
 931               cur != VMOperationQueue_lock) ||
 932               cur->rank() == Mutex::special) {
 933           warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 934         }
 935       }
 936     }
 937 
 938     if (GCALotAtAllSafepoints) {
 939       // We could enter a safepoint here and thus have a gc
 940       InterfaceSupport::check_gc_alot();
 941     }
 942 #endif
 943 }
 944 #endif
 945 
 946 bool Thread::is_in_stack(address adr) const {
 947   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 948   address end = os::current_stack_pointer();
 949   // Allow non Java threads to call this without stack_base
 950   if (_stack_base == NULL) return true;
 951   if (stack_base() >= adr && adr >= end) return true;
 952 
 953   return false;
 954 }
 955 
 956 
 957 bool Thread::is_in_usable_stack(address adr) const {
 958   size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
 959   size_t usable_stack_size = _stack_size - stack_guard_size;
 960 
 961   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
 962 }
 963 
 964 
 965 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 966 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 967 // used for compilation in the future. If that change is made, the need for these methods
 968 // should be revisited, and they should be removed if possible.
 969 
 970 bool Thread::is_lock_owned(address adr) const {
 971   return on_local_stack(adr);
 972 }
 973 
 974 bool Thread::set_as_starting_thread() {
 975  // NOTE: this must be called inside the main thread.
 976   return os::create_main_thread((JavaThread*)this);
 977 }
 978 
 979 static void initialize_class(Symbol* class_name, TRAPS) {
 980   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 981   InstanceKlass::cast(klass)->initialize(CHECK);
 982 }
 983 
 984 
 985 // Creates the initial ThreadGroup
 986 static Handle create_initial_thread_group(TRAPS) {
 987   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
 988   instanceKlassHandle klass (THREAD, k);
 989 
 990   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
 991   {
 992     JavaValue result(T_VOID);
 993     JavaCalls::call_special(&result,
 994                             system_instance,
 995                             klass,
 996                             vmSymbols::object_initializer_name(),
 997                             vmSymbols::void_method_signature(),
 998                             CHECK_NH);
 999   }
1000   Universe::set_system_thread_group(system_instance());
1001 
1002   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1003   {
1004     JavaValue result(T_VOID);
1005     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1006     JavaCalls::call_special(&result,
1007                             main_instance,
1008                             klass,
1009                             vmSymbols::object_initializer_name(),
1010                             vmSymbols::threadgroup_string_void_signature(),
1011                             system_instance,
1012                             string,
1013                             CHECK_NH);
1014   }
1015   return main_instance;
1016 }
1017 
1018 // Creates the initial Thread
1019 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1020   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1021   instanceKlassHandle klass (THREAD, k);
1022   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1023 
1024   java_lang_Thread::set_thread(thread_oop(), thread);
1025   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1026   thread->set_threadObj(thread_oop());
1027 
1028   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1029 
1030   JavaValue result(T_VOID);
1031   JavaCalls::call_special(&result, thread_oop,
1032                                    klass,
1033                                    vmSymbols::object_initializer_name(),
1034                                    vmSymbols::threadgroup_string_void_signature(),
1035                                    thread_group,
1036                                    string,
1037                                    CHECK_NULL);
1038   return thread_oop();
1039 }
1040 
1041 static void call_initializeSystemClass(TRAPS) {
1042   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1043   instanceKlassHandle klass (THREAD, k);
1044 
1045   JavaValue result(T_VOID);
1046   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1047                                          vmSymbols::void_method_signature(), CHECK);
1048 }
1049 
1050 char java_runtime_name[128] = "";
1051 char java_runtime_version[128] = "";
1052 
1053 // extract the JRE name from sun.misc.Version.java_runtime_name
1054 static const char* get_java_runtime_name(TRAPS) {
1055   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1056                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1057   fieldDescriptor fd;
1058   bool found = k != NULL &&
1059                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1060                                                         vmSymbols::string_signature(), &fd);
1061   if (found) {
1062     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1063     if (name_oop == NULL)
1064       return NULL;
1065     const char* name = java_lang_String::as_utf8_string(name_oop,
1066                                                         java_runtime_name,
1067                                                         sizeof(java_runtime_name));
1068     return name;
1069   } else {
1070     return NULL;
1071   }
1072 }
1073 
1074 // extract the JRE version from sun.misc.Version.java_runtime_version
1075 static const char* get_java_runtime_version(TRAPS) {
1076   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1077                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1078   fieldDescriptor fd;
1079   bool found = k != NULL &&
1080                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1081                                                         vmSymbols::string_signature(), &fd);
1082   if (found) {
1083     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1084     if (name_oop == NULL)
1085       return NULL;
1086     const char* name = java_lang_String::as_utf8_string(name_oop,
1087                                                         java_runtime_version,
1088                                                         sizeof(java_runtime_version));
1089     return name;
1090   } else {
1091     return NULL;
1092   }
1093 }
1094 
1095 // General purpose hook into Java code, run once when the VM is initialized.
1096 // The Java library method itself may be changed independently from the VM.
1097 static void call_postVMInitHook(TRAPS) {
1098   Klass* k = SystemDictionary::PostVMInitHook_klass();
1099   instanceKlassHandle klass (THREAD, k);
1100   if (klass.not_null()) {
1101     JavaValue result(T_VOID);
1102     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1103                                            vmSymbols::void_method_signature(),
1104                                            CHECK);
1105   }
1106 }
1107 
1108 static void reset_vm_info_property(TRAPS) {
1109   // the vm info string
1110   ResourceMark rm(THREAD);
1111   const char *vm_info = VM_Version::vm_info_string();
1112 
1113   // java.lang.System class
1114   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1115   instanceKlassHandle klass (THREAD, k);
1116 
1117   // setProperty arguments
1118   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1119   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1120 
1121   // return value
1122   JavaValue r(T_OBJECT);
1123 
1124   // public static String setProperty(String key, String value);
1125   JavaCalls::call_static(&r,
1126                          klass,
1127                          vmSymbols::setProperty_name(),
1128                          vmSymbols::string_string_string_signature(),
1129                          key_str,
1130                          value_str,
1131                          CHECK);
1132 }
1133 
1134 
1135 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1136   assert(thread_group.not_null(), "thread group should be specified");
1137   assert(threadObj() == NULL, "should only create Java thread object once");
1138 
1139   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1140   instanceKlassHandle klass (THREAD, k);
1141   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1142 
1143   java_lang_Thread::set_thread(thread_oop(), this);
1144   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1145   set_threadObj(thread_oop());
1146 
1147   JavaValue result(T_VOID);
1148   if (thread_name != NULL) {
1149     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1150     // Thread gets assigned specified name and null target
1151     JavaCalls::call_special(&result,
1152                             thread_oop,
1153                             klass,
1154                             vmSymbols::object_initializer_name(),
1155                             vmSymbols::threadgroup_string_void_signature(),
1156                             thread_group, // Argument 1
1157                             name,         // Argument 2
1158                             THREAD);
1159   } else {
1160     // Thread gets assigned name "Thread-nnn" and null target
1161     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1162     JavaCalls::call_special(&result,
1163                             thread_oop,
1164                             klass,
1165                             vmSymbols::object_initializer_name(),
1166                             vmSymbols::threadgroup_runnable_void_signature(),
1167                             thread_group, // Argument 1
1168                             Handle(),     // Argument 2
1169                             THREAD);
1170   }
1171 
1172 
1173   if (daemon) {
1174       java_lang_Thread::set_daemon(thread_oop());
1175   }
1176 
1177   if (HAS_PENDING_EXCEPTION) {
1178     return;
1179   }
1180 
1181   KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1182   Handle threadObj(this, this->threadObj());
1183 
1184   JavaCalls::call_special(&result,
1185                          thread_group,
1186                          group,
1187                          vmSymbols::add_method_name(),
1188                          vmSymbols::thread_void_signature(),
1189                          threadObj,          // Arg 1
1190                          THREAD);
1191 
1192 
1193 }
1194 
1195 // NamedThread --  non-JavaThread subclasses with multiple
1196 // uniquely named instances should derive from this.
1197 NamedThread::NamedThread() : Thread() {
1198   _name = NULL;
1199   _processed_thread = NULL;
1200 }
1201 
1202 NamedThread::~NamedThread() {
1203   if (_name != NULL) {
1204     FREE_C_HEAP_ARRAY(char, _name, mtThread);
1205     _name = NULL;
1206   }
1207 }
1208 
1209 void NamedThread::set_name(const char* format, ...) {
1210   guarantee(_name == NULL, "Only get to set name once.");
1211   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1212   guarantee(_name != NULL, "alloc failure");
1213   va_list ap;
1214   va_start(ap, format);
1215   jio_vsnprintf(_name, max_name_len, format, ap);
1216   va_end(ap);
1217 }
1218 
1219 // ======= WatcherThread ========
1220 
1221 // The watcher thread exists to simulate timer interrupts.  It should
1222 // be replaced by an abstraction over whatever native support for
1223 // timer interrupts exists on the platform.
1224 
1225 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1226 bool WatcherThread::_startable = false;
1227 volatile bool  WatcherThread::_should_terminate = false;
1228 
1229 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1230   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1231   if (os::create_thread(this, os::watcher_thread)) {
1232     _watcher_thread = this;
1233 
1234     // Set the watcher thread to the highest OS priority which should not be
1235     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1236     // is created. The only normal thread using this priority is the reference
1237     // handler thread, which runs for very short intervals only.
1238     // If the VMThread's priority is not lower than the WatcherThread profiling
1239     // will be inaccurate.
1240     os::set_priority(this, MaxPriority);
1241     if (!DisableStartThread) {
1242       os::start_thread(this);
1243     }
1244   }
1245 }
1246 
1247 int WatcherThread::sleep() const {
1248   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1249 
1250   // remaining will be zero if there are no tasks,
1251   // causing the WatcherThread to sleep until a task is
1252   // enrolled
1253   int remaining = PeriodicTask::time_to_wait();
1254   int time_slept = 0;
1255 
1256   // we expect this to timeout - we only ever get unparked when
1257   // we should terminate or when a new task has been enrolled
1258   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1259 
1260   jlong time_before_loop = os::javaTimeNanos();
1261 
1262   for (;;) {
1263     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1264     jlong now = os::javaTimeNanos();
1265 
1266     if (remaining == 0) {
1267         // if we didn't have any tasks we could have waited for a long time
1268         // consider the time_slept zero and reset time_before_loop
1269         time_slept = 0;
1270         time_before_loop = now;
1271     } else {
1272         // need to recalulate since we might have new tasks in _tasks
1273         time_slept = (int) ((now - time_before_loop) / 1000000);
1274     }
1275 
1276     // Change to task list or spurious wakeup of some kind
1277     if (timedout || _should_terminate) {
1278         break;
1279     }
1280 
1281     remaining = PeriodicTask::time_to_wait();
1282     if (remaining == 0) {
1283         // Last task was just disenrolled so loop around and wait until
1284         // another task gets enrolled
1285         continue;
1286     }
1287 
1288     remaining -= time_slept;
1289     if (remaining <= 0)
1290       break;
1291   }
1292 
1293   return time_slept;
1294 }
1295 
1296 void WatcherThread::run() {
1297   assert(this == watcher_thread(), "just checking");
1298 
1299   this->record_stack_base_and_size();
1300   this->initialize_thread_local_storage();
1301   this->set_active_handles(JNIHandleBlock::allocate_block());
1302   while(!_should_terminate) {
1303     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1304     assert(watcher_thread() == this,  "thread consistency check");
1305 
1306     // Calculate how long it'll be until the next PeriodicTask work
1307     // should be done, and sleep that amount of time.
1308     int time_waited = sleep();
1309 
1310     if (is_error_reported()) {
1311       // A fatal error has happened, the error handler(VMError::report_and_die)
1312       // should abort JVM after creating an error log file. However in some
1313       // rare cases, the error handler itself might deadlock. Here we try to
1314       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1315       //
1316       // This code is in WatcherThread because WatcherThread wakes up
1317       // periodically so the fatal error handler doesn't need to do anything;
1318       // also because the WatcherThread is less likely to crash than other
1319       // threads.
1320 
1321       for (;;) {
1322         if (!ShowMessageBoxOnError
1323          && (OnError == NULL || OnError[0] == '\0')
1324          && Arguments::abort_hook() == NULL) {
1325              os::sleep(this, 2 * 60 * 1000, false);
1326              fdStream err(defaultStream::output_fd());
1327              err.print_raw_cr("# [ timer expired, abort... ]");
1328              // skip atexit/vm_exit/vm_abort hooks
1329              os::die();
1330         }
1331 
1332         // Wake up 5 seconds later, the fatal handler may reset OnError or
1333         // ShowMessageBoxOnError when it is ready to abort.
1334         os::sleep(this, 5 * 1000, false);
1335       }
1336     }
1337 
1338     PeriodicTask::real_time_tick(time_waited);
1339   }
1340 
1341   // Signal that it is terminated
1342   {
1343     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1344     _watcher_thread = NULL;
1345     Terminator_lock->notify();
1346   }
1347 
1348   // Thread destructor usually does this..
1349   ThreadLocalStorage::set_thread(NULL);
1350 }
1351 
1352 void WatcherThread::start() {
1353   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1354 
1355   if (watcher_thread() == NULL && _startable) {
1356     _should_terminate = false;
1357     // Create the single instance of WatcherThread
1358     new WatcherThread();
1359   }
1360 }
1361 
1362 void WatcherThread::make_startable() {
1363   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1364   _startable = true;
1365 }
1366 
1367 void WatcherThread::stop() {
1368   {
1369     MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1370     _should_terminate = true;
1371     OrderAccess::fence();  // ensure WatcherThread sees update in main loop
1372 
1373     WatcherThread* watcher = watcher_thread();
1374     if (watcher != NULL)
1375       watcher->unpark();
1376   }
1377 
1378   // it is ok to take late safepoints here, if needed
1379   MutexLocker mu(Terminator_lock);
1380 
1381   while(watcher_thread() != NULL) {
1382     // This wait should make safepoint checks, wait without a timeout,
1383     // and wait as a suspend-equivalent condition.
1384     //
1385     // Note: If the FlatProfiler is running, then this thread is waiting
1386     // for the WatcherThread to terminate and the WatcherThread, via the
1387     // FlatProfiler task, is waiting for the external suspend request on
1388     // this thread to complete. wait_for_ext_suspend_completion() will
1389     // eventually timeout, but that takes time. Making this wait a
1390     // suspend-equivalent condition solves that timeout problem.
1391     //
1392     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1393                           Mutex::_as_suspend_equivalent_flag);
1394   }
1395 }
1396 
1397 void WatcherThread::unpark() {
1398   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1399   PeriodicTask_lock->notify();
1400 }
1401 
1402 void WatcherThread::print_on(outputStream* st) const {
1403   st->print("\"%s\" ", name());
1404   Thread::print_on(st);
1405   st->cr();
1406 }
1407 
1408 // ======= JavaThread ========
1409 
1410 // A JavaThread is a normal Java thread
1411 
1412 void JavaThread::initialize() {
1413   // Initialize fields
1414 
1415   // Set the claimed par_id to -1 (ie not claiming any par_ids)
1416   set_claimed_par_id(-1);
1417 
1418   set_saved_exception_pc(NULL);
1419   set_threadObj(NULL);
1420   _anchor.clear();
1421   set_entry_point(NULL);
1422   set_jni_functions(jni_functions());
1423   set_callee_target(NULL);
1424   set_vm_result(NULL);
1425   set_vm_result_2(NULL);
1426   set_vframe_array_head(NULL);
1427   set_vframe_array_last(NULL);
1428   set_deferred_locals(NULL);
1429   set_deopt_mark(NULL);
1430   set_deopt_nmethod(NULL);
1431   clear_must_deopt_id();
1432   set_monitor_chunks(NULL);
1433   set_next(NULL);
1434   set_thread_state(_thread_new);
1435 #if INCLUDE_NMT
1436   set_recorder(NULL);
1437 #endif
1438   _terminated = _not_terminated;
1439   _privileged_stack_top = NULL;
1440   _array_for_gc = NULL;
1441   _suspend_equivalent = false;
1442   _in_deopt_handler = 0;
1443   _doing_unsafe_access = false;
1444   _stack_guard_state = stack_guard_unused;
1445   _exception_oop = NULL;
1446   _exception_pc  = 0;
1447   _exception_handler_pc = 0;
1448   _is_method_handle_return = 0;
1449   _jvmti_thread_state= NULL;
1450   _should_post_on_exceptions_flag = JNI_FALSE;
1451   _jvmti_get_loaded_classes_closure = NULL;
1452   _interp_only_mode    = 0;
1453   _special_runtime_exit_condition = _no_async_condition;
1454   _pending_async_exception = NULL;
1455   _is_compiling = false;
1456   _thread_stat = NULL;
1457   _thread_stat = new ThreadStatistics();
1458   _blocked_on_compilation = false;
1459   _jni_active_critical = 0;
1460   _do_not_unlock_if_synchronized = false;
1461   _cached_monitor_info = NULL;
1462   _parker = Parker::Allocate(this) ;
1463 
1464 #ifndef PRODUCT
1465   _jmp_ring_index = 0;
1466   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1467     record_jump(NULL, NULL, NULL, 0);
1468   }
1469 #endif /* PRODUCT */
1470 
1471   set_thread_profiler(NULL);
1472   if (FlatProfiler::is_active()) {
1473     // This is where we would decide to either give each thread it's own profiler
1474     // or use one global one from FlatProfiler,
1475     // or up to some count of the number of profiled threads, etc.
1476     ThreadProfiler* pp = new ThreadProfiler();
1477     pp->engage();
1478     set_thread_profiler(pp);
1479   }
1480 
1481   // Setup safepoint state info for this thread
1482   ThreadSafepointState::create(this);
1483 
1484   debug_only(_java_call_counter = 0);
1485 
1486   // JVMTI PopFrame support
1487   _popframe_condition = popframe_inactive;
1488   _popframe_preserved_args = NULL;
1489   _popframe_preserved_args_size = 0;
1490 
1491   pd_initialize();
1492 }
1493 
1494 #if INCLUDE_ALL_GCS
1495 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1496 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1497 #endif // INCLUDE_ALL_GCS
1498 
1499 JavaThread::JavaThread(bool is_attaching_via_jni) :
1500   Thread()
1501 #if INCLUDE_ALL_GCS
1502   , _satb_mark_queue(&_satb_mark_queue_set),
1503   _dirty_card_queue(&_dirty_card_queue_set)
1504 #endif // INCLUDE_ALL_GCS
1505 {
1506   initialize();
1507   if (is_attaching_via_jni) {
1508     _jni_attach_state = _attaching_via_jni;
1509   } else {
1510     _jni_attach_state = _not_attaching_via_jni;
1511   }
1512   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1513   _safepoint_visible = false;
1514 }
1515 
1516 bool JavaThread::reguard_stack(address cur_sp) {
1517   if (_stack_guard_state != stack_guard_yellow_disabled) {
1518     return true; // Stack already guarded or guard pages not needed.
1519   }
1520 
1521   if (register_stack_overflow()) {
1522     // For those architectures which have separate register and
1523     // memory stacks, we must check the register stack to see if
1524     // it has overflowed.
1525     return false;
1526   }
1527 
1528   // Java code never executes within the yellow zone: the latter is only
1529   // there to provoke an exception during stack banging.  If java code
1530   // is executing there, either StackShadowPages should be larger, or
1531   // some exception code in c1, c2 or the interpreter isn't unwinding
1532   // when it should.
1533   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1534 
1535   enable_stack_yellow_zone();
1536   return true;
1537 }
1538 
1539 bool JavaThread::reguard_stack(void) {
1540   return reguard_stack(os::current_stack_pointer());
1541 }
1542 
1543 
1544 void JavaThread::block_if_vm_exited() {
1545   if (_terminated == _vm_exited) {
1546     // _vm_exited is set at safepoint, and Threads_lock is never released
1547     // we will block here forever
1548     Threads_lock->lock_without_safepoint_check();
1549     ShouldNotReachHere();
1550   }
1551 }
1552 
1553 
1554 // Remove this ifdef when C1 is ported to the compiler interface.
1555 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1556 
1557 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1558   Thread()
1559 #if INCLUDE_ALL_GCS
1560   , _satb_mark_queue(&_satb_mark_queue_set),
1561   _dirty_card_queue(&_dirty_card_queue_set)
1562 #endif // INCLUDE_ALL_GCS
1563 {
1564   if (TraceThreadEvents) {
1565     tty->print_cr("creating thread %p", this);
1566   }
1567   initialize();
1568   _jni_attach_state = _not_attaching_via_jni;
1569   set_entry_point(entry_point);
1570   // Create the native thread itself.
1571   // %note runtime_23
1572   os::ThreadType thr_type = os::java_thread;
1573   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1574                                                      os::java_thread;
1575   os::create_thread(this, thr_type, stack_sz);
1576   _safepoint_visible = false;
1577   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1578   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1579   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1580   // the exception consists of creating the exception object & initializing it, initialization
1581   // will leave the VM via a JavaCall and then all locks must be unlocked).
1582   //
1583   // The thread is still suspended when we reach here. Thread must be explicit started
1584   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1585   // by calling Threads:add. The reason why this is not done here, is because the thread
1586   // object must be fully initialized (take a look at JVM_Start)
1587 }
1588 
1589 JavaThread::~JavaThread() {
1590   if (TraceThreadEvents) {
1591       tty->print_cr("terminate thread %p", this);
1592   }
1593 
1594   // By now, this thread should already be invisible to safepoint,
1595   // and its per-thread recorder also collected.
1596   assert(!is_safepoint_visible(), "wrong state");
1597 #if INCLUDE_NMT
1598   assert(get_recorder() == NULL, "Already collected");
1599 #endif // INCLUDE_NMT
1600 
1601   // JSR166 -- return the parker to the free list
1602   Parker::Release(_parker);
1603   _parker = NULL ;
1604 
1605   // Free any remaining  previous UnrollBlock
1606   vframeArray* old_array = vframe_array_last();
1607 
1608   if (old_array != NULL) {
1609     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1610     old_array->set_unroll_block(NULL);
1611     delete old_info;
1612     delete old_array;
1613   }
1614 
1615   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1616   if (deferred != NULL) {
1617     // This can only happen if thread is destroyed before deoptimization occurs.
1618     assert(deferred->length() != 0, "empty array!");
1619     do {
1620       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1621       deferred->remove_at(0);
1622       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1623       delete dlv;
1624     } while (deferred->length() != 0);
1625     delete deferred;
1626   }
1627 
1628   // All Java related clean up happens in exit
1629   ThreadSafepointState::destroy(this);
1630   if (_thread_profiler != NULL) delete _thread_profiler;
1631   if (_thread_stat != NULL) delete _thread_stat;
1632 }
1633 
1634 
1635 // The first routine called by a new Java thread
1636 void JavaThread::run() {
1637   // initialize thread-local alloc buffer related fields
1638   this->initialize_tlab();
1639 
1640   // used to test validitity of stack trace backs
1641   this->record_base_of_stack_pointer();
1642 
1643   // Record real stack base and size.
1644   this->record_stack_base_and_size();
1645 
1646   // Initialize thread local storage; set before calling MutexLocker
1647   this->initialize_thread_local_storage();
1648 
1649   this->create_stack_guard_pages();
1650 
1651   this->cache_global_variables();
1652 
1653   // Thread is now sufficient initialized to be handled by the safepoint code as being
1654   // in the VM. Change thread state from _thread_new to _thread_in_vm
1655   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1656 
1657   assert(JavaThread::current() == this, "sanity check");
1658   assert(!Thread::current()->owns_locks(), "sanity check");
1659 
1660   DTRACE_THREAD_PROBE(start, this);
1661 
1662   // This operation might block. We call that after all safepoint checks for a new thread has
1663   // been completed.
1664   this->set_active_handles(JNIHandleBlock::allocate_block());
1665 
1666   if (JvmtiExport::should_post_thread_life()) {
1667     JvmtiExport::post_thread_start(this);
1668   }
1669 
1670   EventThreadStart event;
1671   if (event.should_commit()) {
1672      event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1673      event.commit();
1674   }
1675 
1676   // We call another function to do the rest so we are sure that the stack addresses used
1677   // from there will be lower than the stack base just computed
1678   thread_main_inner();
1679 
1680   // Note, thread is no longer valid at this point!
1681 }
1682 
1683 
1684 void JavaThread::thread_main_inner() {
1685   assert(JavaThread::current() == this, "sanity check");
1686   assert(this->threadObj() != NULL, "just checking");
1687 
1688   // Execute thread entry point unless this thread has a pending exception
1689   // or has been stopped before starting.
1690   // Note: Due to JVM_StopThread we can have pending exceptions already!
1691   if (!this->has_pending_exception() &&
1692       !java_lang_Thread::is_stillborn(this->threadObj())) {
1693     {
1694       ResourceMark rm(this);
1695       this->set_native_thread_name(this->get_thread_name());
1696     }
1697     HandleMark hm(this);
1698     this->entry_point()(this, this);
1699   }
1700 
1701   DTRACE_THREAD_PROBE(stop, this);
1702 
1703   this->exit(false);
1704   delete this;
1705 }
1706 
1707 
1708 static void ensure_join(JavaThread* thread) {
1709   // We do not need to grap the Threads_lock, since we are operating on ourself.
1710   Handle threadObj(thread, thread->threadObj());
1711   assert(threadObj.not_null(), "java thread object must exist");
1712   ObjectLocker lock(threadObj, thread);
1713   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1714   thread->clear_pending_exception();
1715   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1716   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1717   // Clear the native thread instance - this makes isAlive return false and allows the join()
1718   // to complete once we've done the notify_all below
1719   java_lang_Thread::set_thread(threadObj(), NULL);
1720   lock.notify_all(thread);
1721   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1722   thread->clear_pending_exception();
1723 }
1724 
1725 
1726 // For any new cleanup additions, please check to see if they need to be applied to
1727 // cleanup_failed_attach_current_thread as well.
1728 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1729   assert(this == JavaThread::current(),  "thread consistency check");
1730 
1731   HandleMark hm(this);
1732   Handle uncaught_exception(this, this->pending_exception());
1733   this->clear_pending_exception();
1734   Handle threadObj(this, this->threadObj());
1735   assert(threadObj.not_null(), "Java thread object should be created");
1736 
1737   if (get_thread_profiler() != NULL) {
1738     get_thread_profiler()->disengage();
1739     ResourceMark rm;
1740     get_thread_profiler()->print(get_thread_name());
1741   }
1742 
1743 
1744   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1745   {
1746     EXCEPTION_MARK;
1747 
1748     CLEAR_PENDING_EXCEPTION;
1749   }
1750   // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1751   // has to be fixed by a runtime query method
1752   if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1753     // JSR-166: change call from from ThreadGroup.uncaughtException to
1754     // java.lang.Thread.dispatchUncaughtException
1755     if (uncaught_exception.not_null()) {
1756       Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1757       {
1758         EXCEPTION_MARK;
1759         // Check if the method Thread.dispatchUncaughtException() exists. If so
1760         // call it.  Otherwise we have an older library without the JSR-166 changes,
1761         // so call ThreadGroup.uncaughtException()
1762         KlassHandle recvrKlass(THREAD, threadObj->klass());
1763         CallInfo callinfo;
1764         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1765         LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1766                                            vmSymbols::dispatchUncaughtException_name(),
1767                                            vmSymbols::throwable_void_signature(),
1768                                            KlassHandle(), false, false, THREAD);
1769         CLEAR_PENDING_EXCEPTION;
1770         methodHandle method = callinfo.selected_method();
1771         if (method.not_null()) {
1772           JavaValue result(T_VOID);
1773           JavaCalls::call_virtual(&result,
1774                                   threadObj, thread_klass,
1775                                   vmSymbols::dispatchUncaughtException_name(),
1776                                   vmSymbols::throwable_void_signature(),
1777                                   uncaught_exception,
1778                                   THREAD);
1779         } else {
1780           KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1781           JavaValue result(T_VOID);
1782           JavaCalls::call_virtual(&result,
1783                                   group, thread_group,
1784                                   vmSymbols::uncaughtException_name(),
1785                                   vmSymbols::thread_throwable_void_signature(),
1786                                   threadObj,           // Arg 1
1787                                   uncaught_exception,  // Arg 2
1788                                   THREAD);
1789         }
1790         if (HAS_PENDING_EXCEPTION) {
1791           ResourceMark rm(this);
1792           jio_fprintf(defaultStream::error_stream(),
1793                 "\nException: %s thrown from the UncaughtExceptionHandler"
1794                 " in thread \"%s\"\n",
1795                 pending_exception()->klass()->external_name(),
1796                 get_thread_name());
1797           CLEAR_PENDING_EXCEPTION;
1798         }
1799       }
1800     }
1801 
1802     // Called before the java thread exit since we want to read info
1803     // from java_lang_Thread object
1804     EventThreadEnd event;
1805     if (event.should_commit()) {
1806         event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1807         event.commit();
1808     }
1809 
1810     // Call after last event on thread
1811     EVENT_THREAD_EXIT(this);
1812 
1813     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1814     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1815     // is deprecated anyhow.
1816     { int count = 3;
1817       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1818         EXCEPTION_MARK;
1819         JavaValue result(T_VOID);
1820         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1821         JavaCalls::call_virtual(&result,
1822                               threadObj, thread_klass,
1823                               vmSymbols::exit_method_name(),
1824                               vmSymbols::void_method_signature(),
1825                               THREAD);
1826         CLEAR_PENDING_EXCEPTION;
1827       }
1828     }
1829 
1830     // notify JVMTI
1831     if (JvmtiExport::should_post_thread_life()) {
1832       JvmtiExport::post_thread_end(this);
1833     }
1834 
1835     // We have notified the agents that we are exiting, before we go on,
1836     // we must check for a pending external suspend request and honor it
1837     // in order to not surprise the thread that made the suspend request.
1838     while (true) {
1839       {
1840         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1841         if (!is_external_suspend()) {
1842           set_terminated(_thread_exiting);
1843           ThreadService::current_thread_exiting(this);
1844           break;
1845         }
1846         // Implied else:
1847         // Things get a little tricky here. We have a pending external
1848         // suspend request, but we are holding the SR_lock so we
1849         // can't just self-suspend. So we temporarily drop the lock
1850         // and then self-suspend.
1851       }
1852 
1853       ThreadBlockInVM tbivm(this);
1854       java_suspend_self();
1855 
1856       // We're done with this suspend request, but we have to loop around
1857       // and check again. Eventually we will get SR_lock without a pending
1858       // external suspend request and will be able to mark ourselves as
1859       // exiting.
1860     }
1861     // no more external suspends are allowed at this point
1862   } else {
1863     // before_exit() has already posted JVMTI THREAD_END events
1864   }
1865 
1866   // Notify waiters on thread object. This has to be done after exit() is called
1867   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1868   // group should have the destroyed bit set before waiters are notified).
1869   ensure_join(this);
1870   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1871 
1872   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1873   // held by this thread must be released.  A detach operation must only
1874   // get here if there are no Java frames on the stack.  Therefore, any
1875   // owned monitors at this point MUST be JNI-acquired monitors which are
1876   // pre-inflated and in the monitor cache.
1877   //
1878   // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1879   if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1880     assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1881     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1882     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1883   }
1884 
1885   // These things needs to be done while we are still a Java Thread. Make sure that thread
1886   // is in a consistent state, in case GC happens
1887   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1888 
1889   if (active_handles() != NULL) {
1890     JNIHandleBlock* block = active_handles();
1891     set_active_handles(NULL);
1892     JNIHandleBlock::release_block(block);
1893   }
1894 
1895   if (free_handle_block() != NULL) {
1896     JNIHandleBlock* block = free_handle_block();
1897     set_free_handle_block(NULL);
1898     JNIHandleBlock::release_block(block);
1899   }
1900 
1901   // These have to be removed while this is still a valid thread.
1902   remove_stack_guard_pages();
1903 
1904   if (UseTLAB) {
1905     tlab().make_parsable(true);  // retire TLAB
1906   }
1907 
1908   if (JvmtiEnv::environments_might_exist()) {
1909     JvmtiExport::cleanup_thread(this);
1910   }
1911 
1912   // We must flush any deferred card marks before removing a thread from
1913   // the list of active threads.
1914   Universe::heap()->flush_deferred_store_barrier(this);
1915   assert(deferred_card_mark().is_empty(), "Should have been flushed");
1916 
1917 #if INCLUDE_ALL_GCS
1918   // We must flush the G1-related buffers before removing a thread
1919   // from the list of active threads. We must do this after any deferred
1920   // card marks have been flushed (above) so that any entries that are
1921   // added to the thread's dirty card queue as a result are not lost.
1922   if (UseG1GC) {
1923     flush_barrier_queues();
1924   }
1925 #endif // INCLUDE_ALL_GCS
1926 
1927   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1928   Threads::remove(this);
1929 }
1930 
1931 #if INCLUDE_ALL_GCS
1932 // Flush G1-related queues.
1933 void JavaThread::flush_barrier_queues() {
1934   satb_mark_queue().flush();
1935   dirty_card_queue().flush();
1936 }
1937 
1938 void JavaThread::initialize_queues() {
1939   assert(!SafepointSynchronize::is_at_safepoint(),
1940          "we should not be at a safepoint");
1941 
1942   ObjPtrQueue& satb_queue = satb_mark_queue();
1943   SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1944   // The SATB queue should have been constructed with its active
1945   // field set to false.
1946   assert(!satb_queue.is_active(), "SATB queue should not be active");
1947   assert(satb_queue.is_empty(), "SATB queue should be empty");
1948   // If we are creating the thread during a marking cycle, we should
1949   // set the active field of the SATB queue to true.
1950   if (satb_queue_set.is_active()) {
1951     satb_queue.set_active(true);
1952   }
1953 
1954   DirtyCardQueue& dirty_queue = dirty_card_queue();
1955   // The dirty card queue should have been constructed with its
1956   // active field set to true.
1957   assert(dirty_queue.is_active(), "dirty card queue should be active");
1958 }
1959 #endif // INCLUDE_ALL_GCS
1960 
1961 void JavaThread::cleanup_failed_attach_current_thread() {
1962   if (get_thread_profiler() != NULL) {
1963     get_thread_profiler()->disengage();
1964     ResourceMark rm;
1965     get_thread_profiler()->print(get_thread_name());
1966   }
1967 
1968   if (active_handles() != NULL) {
1969     JNIHandleBlock* block = active_handles();
1970     set_active_handles(NULL);
1971     JNIHandleBlock::release_block(block);
1972   }
1973 
1974   if (free_handle_block() != NULL) {
1975     JNIHandleBlock* block = free_handle_block();
1976     set_free_handle_block(NULL);
1977     JNIHandleBlock::release_block(block);
1978   }
1979 
1980   // These have to be removed while this is still a valid thread.
1981   remove_stack_guard_pages();
1982 
1983   if (UseTLAB) {
1984     tlab().make_parsable(true);  // retire TLAB, if any
1985   }
1986 
1987 #if INCLUDE_ALL_GCS
1988   if (UseG1GC) {
1989     flush_barrier_queues();
1990   }
1991 #endif // INCLUDE_ALL_GCS
1992 
1993   Threads::remove(this);
1994   delete this;
1995 }
1996 
1997 
1998 
1999 
2000 JavaThread* JavaThread::active() {
2001   Thread* thread = ThreadLocalStorage::thread();
2002   assert(thread != NULL, "just checking");
2003   if (thread->is_Java_thread()) {
2004     return (JavaThread*) thread;
2005   } else {
2006     assert(thread->is_VM_thread(), "this must be a vm thread");
2007     VM_Operation* op = ((VMThread*) thread)->vm_operation();
2008     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2009     assert(ret->is_Java_thread(), "must be a Java thread");
2010     return ret;
2011   }
2012 }
2013 
2014 bool JavaThread::is_lock_owned(address adr) const {
2015   if (Thread::is_lock_owned(adr)) return true;
2016 
2017   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2018     if (chunk->contains(adr)) return true;
2019   }
2020 
2021   return false;
2022 }
2023 
2024 
2025 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2026   chunk->set_next(monitor_chunks());
2027   set_monitor_chunks(chunk);
2028 }
2029 
2030 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2031   guarantee(monitor_chunks() != NULL, "must be non empty");
2032   if (monitor_chunks() == chunk) {
2033     set_monitor_chunks(chunk->next());
2034   } else {
2035     MonitorChunk* prev = monitor_chunks();
2036     while (prev->next() != chunk) prev = prev->next();
2037     prev->set_next(chunk->next());
2038   }
2039 }
2040 
2041 // JVM support.
2042 
2043 // Note: this function shouldn't block if it's called in
2044 // _thread_in_native_trans state (such as from
2045 // check_special_condition_for_native_trans()).
2046 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2047 
2048   if (has_last_Java_frame() && has_async_condition()) {
2049     // If we are at a polling page safepoint (not a poll return)
2050     // then we must defer async exception because live registers
2051     // will be clobbered by the exception path. Poll return is
2052     // ok because the call we a returning from already collides
2053     // with exception handling registers and so there is no issue.
2054     // (The exception handling path kills call result registers but
2055     //  this is ok since the exception kills the result anyway).
2056 
2057     if (is_at_poll_safepoint()) {
2058       // if the code we are returning to has deoptimized we must defer
2059       // the exception otherwise live registers get clobbered on the
2060       // exception path before deoptimization is able to retrieve them.
2061       //
2062       RegisterMap map(this, false);
2063       frame caller_fr = last_frame().sender(&map);
2064       assert(caller_fr.is_compiled_frame(), "what?");
2065       if (caller_fr.is_deoptimized_frame()) {
2066         if (TraceExceptions) {
2067           ResourceMark rm;
2068           tty->print_cr("deferred async exception at compiled safepoint");
2069         }
2070         return;
2071       }
2072     }
2073   }
2074 
2075   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2076   if (condition == _no_async_condition) {
2077     // Conditions have changed since has_special_runtime_exit_condition()
2078     // was called:
2079     // - if we were here only because of an external suspend request,
2080     //   then that was taken care of above (or cancelled) so we are done
2081     // - if we were here because of another async request, then it has
2082     //   been cleared between the has_special_runtime_exit_condition()
2083     //   and now so again we are done
2084     return;
2085   }
2086 
2087   // Check for pending async. exception
2088   if (_pending_async_exception != NULL) {
2089     // Only overwrite an already pending exception, if it is not a threadDeath.
2090     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2091 
2092       // We cannot call Exceptions::_throw(...) here because we cannot block
2093       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2094 
2095       if (TraceExceptions) {
2096         ResourceMark rm;
2097         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2098         if (has_last_Java_frame() ) {
2099           frame f = last_frame();
2100           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2101         }
2102         tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2103       }
2104       _pending_async_exception = NULL;
2105       clear_has_async_exception();
2106     }
2107   }
2108 
2109   if (check_unsafe_error &&
2110       condition == _async_unsafe_access_error && !has_pending_exception()) {
2111     condition = _no_async_condition;  // done
2112     switch (thread_state()) {
2113     case _thread_in_vm:
2114       {
2115         JavaThread* THREAD = this;
2116         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2117       }
2118     case _thread_in_native:
2119       {
2120         ThreadInVMfromNative tiv(this);
2121         JavaThread* THREAD = this;
2122         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2123       }
2124     case _thread_in_Java:
2125       {
2126         ThreadInVMfromJava tiv(this);
2127         JavaThread* THREAD = this;
2128         THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2129       }
2130     default:
2131       ShouldNotReachHere();
2132     }
2133   }
2134 
2135   assert(condition == _no_async_condition || has_pending_exception() ||
2136          (!check_unsafe_error && condition == _async_unsafe_access_error),
2137          "must have handled the async condition, if no exception");
2138 }
2139 
2140 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2141   //
2142   // Check for pending external suspend. Internal suspend requests do
2143   // not use handle_special_runtime_exit_condition().
2144   // If JNIEnv proxies are allowed, don't self-suspend if the target
2145   // thread is not the current thread. In older versions of jdbx, jdbx
2146   // threads could call into the VM with another thread's JNIEnv so we
2147   // can be here operating on behalf of a suspended thread (4432884).
2148   bool do_self_suspend = is_external_suspend_with_lock();
2149   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2150     //
2151     // Because thread is external suspended the safepoint code will count
2152     // thread as at a safepoint. This can be odd because we can be here
2153     // as _thread_in_Java which would normally transition to _thread_blocked
2154     // at a safepoint. We would like to mark the thread as _thread_blocked
2155     // before calling java_suspend_self like all other callers of it but
2156     // we must then observe proper safepoint protocol. (We can't leave
2157     // _thread_blocked with a safepoint in progress). However we can be
2158     // here as _thread_in_native_trans so we can't use a normal transition
2159     // constructor/destructor pair because they assert on that type of
2160     // transition. We could do something like:
2161     //
2162     // JavaThreadState state = thread_state();
2163     // set_thread_state(_thread_in_vm);
2164     // {
2165     //   ThreadBlockInVM tbivm(this);
2166     //   java_suspend_self()
2167     // }
2168     // set_thread_state(_thread_in_vm_trans);
2169     // if (safepoint) block;
2170     // set_thread_state(state);
2171     //
2172     // but that is pretty messy. Instead we just go with the way the
2173     // code has worked before and note that this is the only path to
2174     // java_suspend_self that doesn't put the thread in _thread_blocked
2175     // mode.
2176 
2177     frame_anchor()->make_walkable(this);
2178     java_suspend_self();
2179 
2180     // We might be here for reasons in addition to the self-suspend request
2181     // so check for other async requests.
2182   }
2183 
2184   if (check_asyncs) {
2185     check_and_handle_async_exceptions();
2186   }
2187 }
2188 
2189 void JavaThread::send_thread_stop(oop java_throwable)  {
2190   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2191   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2192   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2193 
2194   // Do not throw asynchronous exceptions against the compiler thread
2195   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2196   if (is_Compiler_thread()) return;
2197 
2198   {
2199     // Actually throw the Throwable against the target Thread - however
2200     // only if there is no thread death exception installed already.
2201     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2202       // If the topmost frame is a runtime stub, then we are calling into
2203       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2204       // must deoptimize the caller before continuing, as the compiled  exception handler table
2205       // may not be valid
2206       if (has_last_Java_frame()) {
2207         frame f = last_frame();
2208         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2209           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2210           RegisterMap reg_map(this, UseBiasedLocking);
2211           frame compiled_frame = f.sender(&reg_map);
2212           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2213             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2214           }
2215         }
2216       }
2217 
2218       // Set async. pending exception in thread.
2219       set_pending_async_exception(java_throwable);
2220 
2221       if (TraceExceptions) {
2222        ResourceMark rm;
2223        tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2224       }
2225       // for AbortVMOnException flag
2226       NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2227     }
2228   }
2229 
2230 
2231   // Interrupt thread so it will wake up from a potential wait()
2232   Thread::interrupt(this);
2233 }
2234 
2235 // External suspension mechanism.
2236 //
2237 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2238 // to any VM_locks and it is at a transition
2239 // Self-suspension will happen on the transition out of the vm.
2240 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2241 //
2242 // Guarantees on return:
2243 //   + Target thread will not execute any new bytecode (that's why we need to
2244 //     force a safepoint)
2245 //   + Target thread will not enter any new monitors
2246 //
2247 void JavaThread::java_suspend() {
2248   { MutexLocker mu(Threads_lock);
2249     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2250        return;
2251     }
2252   }
2253 
2254   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2255     if (!is_external_suspend()) {
2256       // a racing resume has cancelled us; bail out now
2257       return;
2258     }
2259 
2260     // suspend is done
2261     uint32_t debug_bits = 0;
2262     // Warning: is_ext_suspend_completed() may temporarily drop the
2263     // SR_lock to allow the thread to reach a stable thread state if
2264     // it is currently in a transient thread state.
2265     if (is_ext_suspend_completed(false /* !called_by_wait */,
2266                                  SuspendRetryDelay, &debug_bits) ) {
2267       return;
2268     }
2269   }
2270 
2271   VM_ForceSafepoint vm_suspend;
2272   VMThread::execute(&vm_suspend);
2273 }
2274 
2275 // Part II of external suspension.
2276 // A JavaThread self suspends when it detects a pending external suspend
2277 // request. This is usually on transitions. It is also done in places
2278 // where continuing to the next transition would surprise the caller,
2279 // e.g., monitor entry.
2280 //
2281 // Returns the number of times that the thread self-suspended.
2282 //
2283 // Note: DO NOT call java_suspend_self() when you just want to block current
2284 //       thread. java_suspend_self() is the second stage of cooperative
2285 //       suspension for external suspend requests and should only be used
2286 //       to complete an external suspend request.
2287 //
2288 int JavaThread::java_suspend_self() {
2289   int ret = 0;
2290 
2291   // we are in the process of exiting so don't suspend
2292   if (is_exiting()) {
2293      clear_external_suspend();
2294      return ret;
2295   }
2296 
2297   assert(_anchor.walkable() ||
2298     (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2299     "must have walkable stack");
2300 
2301   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2302 
2303   assert(!this->is_ext_suspended(),
2304     "a thread trying to self-suspend should not already be suspended");
2305 
2306   if (this->is_suspend_equivalent()) {
2307     // If we are self-suspending as a result of the lifting of a
2308     // suspend equivalent condition, then the suspend_equivalent
2309     // flag is not cleared until we set the ext_suspended flag so
2310     // that wait_for_ext_suspend_completion() returns consistent
2311     // results.
2312     this->clear_suspend_equivalent();
2313   }
2314 
2315   // A racing resume may have cancelled us before we grabbed SR_lock
2316   // above. Or another external suspend request could be waiting for us
2317   // by the time we return from SR_lock()->wait(). The thread
2318   // that requested the suspension may already be trying to walk our
2319   // stack and if we return now, we can change the stack out from under
2320   // it. This would be a "bad thing (TM)" and cause the stack walker
2321   // to crash. We stay self-suspended until there are no more pending
2322   // external suspend requests.
2323   while (is_external_suspend()) {
2324     ret++;
2325     this->set_ext_suspended();
2326 
2327     // _ext_suspended flag is cleared by java_resume()
2328     while (is_ext_suspended()) {
2329       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2330     }
2331   }
2332 
2333   return ret;
2334 }
2335 
2336 #ifdef ASSERT
2337 // verify the JavaThread has not yet been published in the Threads::list, and
2338 // hence doesn't need protection from concurrent access at this stage
2339 void JavaThread::verify_not_published() {
2340   if (!Threads_lock->owned_by_self()) {
2341    MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
2342    assert( !Threads::includes(this),
2343            "java thread shouldn't have been published yet!");
2344   }
2345   else {
2346    assert( !Threads::includes(this),
2347            "java thread shouldn't have been published yet!");
2348   }
2349 }
2350 #endif
2351 
2352 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2353 // progress or when _suspend_flags is non-zero.
2354 // Current thread needs to self-suspend if there is a suspend request and/or
2355 // block if a safepoint is in progress.
2356 // Async exception ISN'T checked.
2357 // Note only the ThreadInVMfromNative transition can call this function
2358 // directly and when thread state is _thread_in_native_trans
2359 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2360   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2361 
2362   JavaThread *curJT = JavaThread::current();
2363   bool do_self_suspend = thread->is_external_suspend();
2364 
2365   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2366 
2367   // If JNIEnv proxies are allowed, don't self-suspend if the target
2368   // thread is not the current thread. In older versions of jdbx, jdbx
2369   // threads could call into the VM with another thread's JNIEnv so we
2370   // can be here operating on behalf of a suspended thread (4432884).
2371   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2372     JavaThreadState state = thread->thread_state();
2373 
2374     // We mark this thread_blocked state as a suspend-equivalent so
2375     // that a caller to is_ext_suspend_completed() won't be confused.
2376     // The suspend-equivalent state is cleared by java_suspend_self().
2377     thread->set_suspend_equivalent();
2378 
2379     // If the safepoint code sees the _thread_in_native_trans state, it will
2380     // wait until the thread changes to other thread state. There is no
2381     // guarantee on how soon we can obtain the SR_lock and complete the
2382     // self-suspend request. It would be a bad idea to let safepoint wait for
2383     // too long. Temporarily change the state to _thread_blocked to
2384     // let the VM thread know that this thread is ready for GC. The problem
2385     // of changing thread state is that safepoint could happen just after
2386     // java_suspend_self() returns after being resumed, and VM thread will
2387     // see the _thread_blocked state. We must check for safepoint
2388     // after restoring the state and make sure we won't leave while a safepoint
2389     // is in progress.
2390     thread->set_thread_state(_thread_blocked);
2391     thread->java_suspend_self();
2392     thread->set_thread_state(state);
2393     // Make sure new state is seen by VM thread
2394     if (os::is_MP()) {
2395       if (UseMembar) {
2396         // Force a fence between the write above and read below
2397         OrderAccess::fence();
2398       } else {
2399         // Must use this rather than serialization page in particular on Windows
2400         InterfaceSupport::serialize_memory(thread);
2401       }
2402     }
2403   }
2404 
2405   if (SafepointSynchronize::do_call_back()) {
2406     // If we are safepointing, then block the caller which may not be
2407     // the same as the target thread (see above).
2408     SafepointSynchronize::block(curJT);
2409   }
2410 
2411   if (thread->is_deopt_suspend()) {
2412     thread->clear_deopt_suspend();
2413     RegisterMap map(thread, false);
2414     frame f = thread->last_frame();
2415     while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2416       f = f.sender(&map);
2417     }
2418     if (f.id() == thread->must_deopt_id()) {
2419       thread->clear_must_deopt_id();
2420       f.deoptimize(thread);
2421     } else {
2422       fatal("missed deoptimization!");
2423     }
2424   }
2425 }
2426 
2427 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2428 // progress or when _suspend_flags is non-zero.
2429 // Current thread needs to self-suspend if there is a suspend request and/or
2430 // block if a safepoint is in progress.
2431 // Also check for pending async exception (not including unsafe access error).
2432 // Note only the native==>VM/Java barriers can call this function and when
2433 // thread state is _thread_in_native_trans.
2434 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2435   check_safepoint_and_suspend_for_native_trans(thread);
2436 
2437   if (thread->has_async_exception()) {
2438     // We are in _thread_in_native_trans state, don't handle unsafe
2439     // access error since that may block.
2440     thread->check_and_handle_async_exceptions(false);
2441   }
2442 }
2443 
2444 // This is a variant of the normal
2445 // check_special_condition_for_native_trans with slightly different
2446 // semantics for use by critical native wrappers.  It does all the
2447 // normal checks but also performs the transition back into
2448 // thread_in_Java state.  This is required so that critical natives
2449 // can potentially block and perform a GC if they are the last thread
2450 // exiting the GC_locker.
2451 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2452   check_special_condition_for_native_trans(thread);
2453 
2454   // Finish the transition
2455   thread->set_thread_state(_thread_in_Java);
2456 
2457   if (thread->do_critical_native_unlock()) {
2458     ThreadInVMfromJavaNoAsyncException tiv(thread);
2459     GC_locker::unlock_critical(thread);
2460     thread->clear_critical_native_unlock();
2461   }
2462 }
2463 
2464 // We need to guarantee the Threads_lock here, since resumes are not
2465 // allowed during safepoint synchronization
2466 // Can only resume from an external suspension
2467 void JavaThread::java_resume() {
2468   assert_locked_or_safepoint(Threads_lock);
2469 
2470   // Sanity check: thread is gone, has started exiting or the thread
2471   // was not externally suspended.
2472   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2473     return;
2474   }
2475 
2476   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2477 
2478   clear_external_suspend();
2479 
2480   if (is_ext_suspended()) {
2481     clear_ext_suspended();
2482     SR_lock()->notify_all();
2483   }
2484 }
2485 
2486 void JavaThread::create_stack_guard_pages() {
2487   if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2488   address low_addr = stack_base() - stack_size();
2489   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2490 
2491   int allocate = os::allocate_stack_guard_pages();
2492   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2493 
2494   if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2495     warning("Attempt to allocate stack guard pages failed.");
2496     return;
2497   }
2498 
2499   if (os::guard_memory((char *) low_addr, len)) {
2500     _stack_guard_state = stack_guard_enabled;
2501   } else {
2502     warning("Attempt to protect stack guard pages failed.");
2503     if (os::uncommit_memory((char *) low_addr, len)) {
2504       warning("Attempt to deallocate stack guard pages failed.");
2505     }
2506   }
2507 }
2508 
2509 void JavaThread::remove_stack_guard_pages() {
2510   assert(Thread::current() == this, "from different thread");
2511   if (_stack_guard_state == stack_guard_unused) return;
2512   address low_addr = stack_base() - stack_size();
2513   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2514 
2515   if (os::allocate_stack_guard_pages()) {
2516     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2517       _stack_guard_state = stack_guard_unused;
2518     } else {
2519       warning("Attempt to deallocate stack guard pages failed.");
2520     }
2521   } else {
2522     if (_stack_guard_state == stack_guard_unused) return;
2523     if (os::unguard_memory((char *) low_addr, len)) {
2524       _stack_guard_state = stack_guard_unused;
2525     } else {
2526         warning("Attempt to unprotect stack guard pages failed.");
2527     }
2528   }
2529 }
2530 
2531 void JavaThread::enable_stack_yellow_zone() {
2532   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2533   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2534 
2535   // The base notation is from the stacks point of view, growing downward.
2536   // We need to adjust it to work correctly with guard_memory()
2537   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2538 
2539   guarantee(base < stack_base(),"Error calculating stack yellow zone");
2540   guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2541 
2542   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2543     _stack_guard_state = stack_guard_enabled;
2544   } else {
2545     warning("Attempt to guard stack yellow zone failed.");
2546   }
2547   enable_register_stack_guard();
2548 }
2549 
2550 void JavaThread::disable_stack_yellow_zone() {
2551   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2552   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2553 
2554   // Simply return if called for a thread that does not use guard pages.
2555   if (_stack_guard_state == stack_guard_unused) return;
2556 
2557   // The base notation is from the stacks point of view, growing downward.
2558   // We need to adjust it to work correctly with guard_memory()
2559   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2560 
2561   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2562     _stack_guard_state = stack_guard_yellow_disabled;
2563   } else {
2564     warning("Attempt to unguard stack yellow zone failed.");
2565   }
2566   disable_register_stack_guard();
2567 }
2568 
2569 void JavaThread::enable_stack_red_zone() {
2570   // The base notation is from the stacks point of view, growing downward.
2571   // We need to adjust it to work correctly with guard_memory()
2572   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2573   address base = stack_red_zone_base() - stack_red_zone_size();
2574 
2575   guarantee(base < stack_base(),"Error calculating stack red zone");
2576   guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2577 
2578   if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2579     warning("Attempt to guard stack red zone failed.");
2580   }
2581 }
2582 
2583 void JavaThread::disable_stack_red_zone() {
2584   // The base notation is from the stacks point of view, growing downward.
2585   // We need to adjust it to work correctly with guard_memory()
2586   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2587   address base = stack_red_zone_base() - stack_red_zone_size();
2588   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2589     warning("Attempt to unguard stack red zone failed.");
2590   }
2591 }
2592 
2593 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2594   // ignore is there is no stack
2595   if (!has_last_Java_frame()) return;
2596   // traverse the stack frames. Starts from top frame.
2597   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2598     frame* fr = fst.current();
2599     f(fr, fst.register_map());
2600   }
2601 }
2602 
2603 
2604 #ifndef PRODUCT
2605 // Deoptimization
2606 // Function for testing deoptimization
2607 void JavaThread::deoptimize() {
2608   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2609   StackFrameStream fst(this, UseBiasedLocking);
2610   bool deopt = false;           // Dump stack only if a deopt actually happens.
2611   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2612   // Iterate over all frames in the thread and deoptimize
2613   for(; !fst.is_done(); fst.next()) {
2614     if(fst.current()->can_be_deoptimized()) {
2615 
2616       if (only_at) {
2617         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2618         // consists of comma or carriage return separated numbers so
2619         // search for the current bci in that string.
2620         address pc = fst.current()->pc();
2621         nmethod* nm =  (nmethod*) fst.current()->cb();
2622         ScopeDesc* sd = nm->scope_desc_at( pc);
2623         char buffer[8];
2624         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2625         size_t len = strlen(buffer);
2626         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2627         while (found != NULL) {
2628           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2629               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2630             // Check that the bci found is bracketed by terminators.
2631             break;
2632           }
2633           found = strstr(found + 1, buffer);
2634         }
2635         if (!found) {
2636           continue;
2637         }
2638       }
2639 
2640       if (DebugDeoptimization && !deopt) {
2641         deopt = true; // One-time only print before deopt
2642         tty->print_cr("[BEFORE Deoptimization]");
2643         trace_frames();
2644         trace_stack();
2645       }
2646       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2647     }
2648   }
2649 
2650   if (DebugDeoptimization && deopt) {
2651     tty->print_cr("[AFTER Deoptimization]");
2652     trace_frames();
2653   }
2654 }
2655 
2656 
2657 // Make zombies
2658 void JavaThread::make_zombies() {
2659   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2660     if (fst.current()->can_be_deoptimized()) {
2661       // it is a Java nmethod
2662       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2663       nm->make_not_entrant();
2664     }
2665   }
2666 }
2667 #endif // PRODUCT
2668 
2669 
2670 void JavaThread::deoptimized_wrt_marked_nmethods() {
2671   if (!has_last_Java_frame()) return;
2672   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2673   StackFrameStream fst(this, UseBiasedLocking);
2674   for(; !fst.is_done(); fst.next()) {
2675     if (fst.current()->should_be_deoptimized()) {
2676       if (LogCompilation && xtty != NULL) {
2677         nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2678         xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2679                    this->name(), nm != NULL ? nm->compile_id() : -1);
2680       }
2681 
2682       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2683     }
2684   }
2685 }
2686 
2687 
2688 // GC support
2689 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2690 
2691 void JavaThread::gc_epilogue() {
2692   frames_do(frame_gc_epilogue);
2693 }
2694 
2695 
2696 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2697 
2698 void JavaThread::gc_prologue() {
2699   frames_do(frame_gc_prologue);
2700 }
2701 
2702 // If the caller is a NamedThread, then remember, in the current scope,
2703 // the given JavaThread in its _processed_thread field.
2704 class RememberProcessedThread: public StackObj {
2705   NamedThread* _cur_thr;
2706 public:
2707   RememberProcessedThread(JavaThread* jthr) {
2708     Thread* thread = Thread::current();
2709     if (thread->is_Named_thread()) {
2710       _cur_thr = (NamedThread *)thread;
2711       _cur_thr->set_processed_thread(jthr);
2712     } else {
2713       _cur_thr = NULL;
2714     }
2715   }
2716 
2717   ~RememberProcessedThread() {
2718     if (_cur_thr) {
2719       _cur_thr->set_processed_thread(NULL);
2720     }
2721   }
2722 };
2723 
2724 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2725   // Verify that the deferred card marks have been flushed.
2726   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2727 
2728   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2729   // since there may be more than one thread using each ThreadProfiler.
2730 
2731   // Traverse the GCHandles
2732   Thread::oops_do(f, cld_f, cf);
2733 
2734   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2735           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2736 
2737   if (has_last_Java_frame()) {
2738     // Record JavaThread to GC thread
2739     RememberProcessedThread rpt(this);
2740 
2741     // Traverse the privileged stack
2742     if (_privileged_stack_top != NULL) {
2743       _privileged_stack_top->oops_do(f);
2744     }
2745 
2746     // traverse the registered growable array
2747     if (_array_for_gc != NULL) {
2748       for (int index = 0; index < _array_for_gc->length(); index++) {
2749         f->do_oop(_array_for_gc->adr_at(index));
2750       }
2751     }
2752 
2753     // Traverse the monitor chunks
2754     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2755       chunk->oops_do(f);
2756     }
2757 
2758     // Traverse the execution stack
2759     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2760       fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2761     }
2762   }
2763 
2764   // callee_target is never live across a gc point so NULL it here should
2765   // it still contain a methdOop.
2766 
2767   set_callee_target(NULL);
2768 
2769   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2770   // If we have deferred set_locals there might be oops waiting to be
2771   // written
2772   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2773   if (list != NULL) {
2774     for (int i = 0; i < list->length(); i++) {
2775       list->at(i)->oops_do(f);
2776     }
2777   }
2778 
2779   // Traverse instance variables at the end since the GC may be moving things
2780   // around using this function
2781   f->do_oop((oop*) &_threadObj);
2782   f->do_oop((oop*) &_vm_result);
2783   f->do_oop((oop*) &_exception_oop);
2784   f->do_oop((oop*) &_pending_async_exception);
2785 
2786   if (jvmti_thread_state() != NULL) {
2787     jvmti_thread_state()->oops_do(f);
2788   }
2789 }
2790 
2791 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2792   Thread::nmethods_do(cf);  // (super method is a no-op)
2793 
2794   assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2795           (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2796 
2797   if (has_last_Java_frame()) {
2798     // Traverse the execution stack
2799     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2800       fst.current()->nmethods_do(cf);
2801     }
2802   }
2803 }
2804 
2805 void JavaThread::metadata_do(void f(Metadata*)) {
2806   Thread::metadata_do(f);
2807   if (has_last_Java_frame()) {
2808     // Traverse the execution stack to call f() on the methods in the stack
2809     for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2810       fst.current()->metadata_do(f);
2811     }
2812   } else if (is_Compiler_thread()) {
2813     // need to walk ciMetadata in current compile tasks to keep alive.
2814     CompilerThread* ct = (CompilerThread*)this;
2815     if (ct->env() != NULL) {
2816       ct->env()->metadata_do(f);
2817     }
2818   }
2819 }
2820 
2821 // Printing
2822 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2823   switch (_thread_state) {
2824   case _thread_uninitialized:     return "_thread_uninitialized";
2825   case _thread_new:               return "_thread_new";
2826   case _thread_new_trans:         return "_thread_new_trans";
2827   case _thread_in_native:         return "_thread_in_native";
2828   case _thread_in_native_trans:   return "_thread_in_native_trans";
2829   case _thread_in_vm:             return "_thread_in_vm";
2830   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2831   case _thread_in_Java:           return "_thread_in_Java";
2832   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2833   case _thread_blocked:           return "_thread_blocked";
2834   case _thread_blocked_trans:     return "_thread_blocked_trans";
2835   default:                        return "unknown thread state";
2836   }
2837 }
2838 
2839 #ifndef PRODUCT
2840 void JavaThread::print_thread_state_on(outputStream *st) const {
2841   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2842 };
2843 void JavaThread::print_thread_state() const {
2844   print_thread_state_on(tty);
2845 };
2846 #endif // PRODUCT
2847 
2848 // Called by Threads::print() for VM_PrintThreads operation
2849 void JavaThread::print_on(outputStream *st) const {
2850   st->print("\"%s\" ", get_thread_name());
2851   oop thread_oop = threadObj();
2852   if (thread_oop != NULL) {
2853     st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2854     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2855     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2856   }
2857   Thread::print_on(st);
2858   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2859   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2860   if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2861     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2862   }
2863 #ifndef PRODUCT
2864   print_thread_state_on(st);
2865   _safepoint_state->print_on(st);
2866 #endif // PRODUCT
2867 }
2868 
2869 // Called by fatal error handler. The difference between this and
2870 // JavaThread::print() is that we can't grab lock or allocate memory.
2871 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2872   st->print("JavaThread \"%s\"",  get_thread_name_string(buf, buflen));
2873   oop thread_obj = threadObj();
2874   if (thread_obj != NULL) {
2875      if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2876   }
2877   st->print(" [");
2878   st->print("%s", _get_thread_state_name(_thread_state));
2879   if (osthread()) {
2880     st->print(", id=%d", osthread()->thread_id());
2881   }
2882   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2883             _stack_base - _stack_size, _stack_base);
2884   st->print("]");
2885   return;
2886 }
2887 
2888 // Verification
2889 
2890 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2891 
2892 void JavaThread::verify() {
2893   // Verify oops in the thread.
2894   oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2895 
2896   // Verify the stack frames.
2897   frames_do(frame_verify);
2898 }
2899 
2900 // CR 6300358 (sub-CR 2137150)
2901 // Most callers of this method assume that it can't return NULL but a
2902 // thread may not have a name whilst it is in the process of attaching to
2903 // the VM - see CR 6412693, and there are places where a JavaThread can be
2904 // seen prior to having it's threadObj set (eg JNI attaching threads and
2905 // if vm exit occurs during initialization). These cases can all be accounted
2906 // for such that this method never returns NULL.
2907 const char* JavaThread::get_thread_name() const {
2908 #ifdef ASSERT
2909   // early safepoints can hit while current thread does not yet have TLS
2910   if (!SafepointSynchronize::is_at_safepoint()) {
2911     Thread *cur = Thread::current();
2912     if (!(cur->is_Java_thread() && cur == this)) {
2913       // Current JavaThreads are allowed to get their own name without
2914       // the Threads_lock.
2915       assert_locked_or_safepoint(Threads_lock);
2916     }
2917   }
2918 #endif // ASSERT
2919     return get_thread_name_string();
2920 }
2921 
2922 // Returns a non-NULL representation of this thread's name, or a suitable
2923 // descriptive string if there is no set name
2924 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2925   const char* name_str;
2926   oop thread_obj = threadObj();
2927   if (thread_obj != NULL) {
2928     typeArrayOop name = java_lang_Thread::name(thread_obj);
2929     if (name != NULL) {
2930       if (buf == NULL) {
2931         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2932       }
2933       else {
2934         name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2935       }
2936     }
2937     else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2938       name_str = "<no-name - thread is attaching>";
2939     }
2940     else {
2941       name_str = Thread::name();
2942     }
2943   }
2944   else {
2945     name_str = Thread::name();
2946   }
2947   assert(name_str != NULL, "unexpected NULL thread name");
2948   return name_str;
2949 }
2950 
2951 
2952 const char* JavaThread::get_threadgroup_name() const {
2953   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2954   oop thread_obj = threadObj();
2955   if (thread_obj != NULL) {
2956     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2957     if (thread_group != NULL) {
2958       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2959       // ThreadGroup.name can be null
2960       if (name != NULL) {
2961         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2962         return str;
2963       }
2964     }
2965   }
2966   return NULL;
2967 }
2968 
2969 const char* JavaThread::get_parent_name() const {
2970   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2971   oop thread_obj = threadObj();
2972   if (thread_obj != NULL) {
2973     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2974     if (thread_group != NULL) {
2975       oop parent = java_lang_ThreadGroup::parent(thread_group);
2976       if (parent != NULL) {
2977         typeArrayOop name = java_lang_ThreadGroup::name(parent);
2978         // ThreadGroup.name can be null
2979         if (name != NULL) {
2980           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2981           return str;
2982         }
2983       }
2984     }
2985   }
2986   return NULL;
2987 }
2988 
2989 ThreadPriority JavaThread::java_priority() const {
2990   oop thr_oop = threadObj();
2991   if (thr_oop == NULL) return NormPriority; // Bootstrapping
2992   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2993   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2994   return priority;
2995 }
2996 
2997 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2998 
2999   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3000   // Link Java Thread object <-> C++ Thread
3001 
3002   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3003   // and put it into a new Handle.  The Handle "thread_oop" can then
3004   // be used to pass the C++ thread object to other methods.
3005 
3006   // Set the Java level thread object (jthread) field of the
3007   // new thread (a JavaThread *) to C++ thread object using the
3008   // "thread_oop" handle.
3009 
3010   // Set the thread field (a JavaThread *) of the
3011   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3012 
3013   Handle thread_oop(Thread::current(),
3014                     JNIHandles::resolve_non_null(jni_thread));
3015   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3016     "must be initialized");
3017   set_threadObj(thread_oop());
3018   java_lang_Thread::set_thread(thread_oop(), this);
3019 
3020   if (prio == NoPriority) {
3021     prio = java_lang_Thread::priority(thread_oop());
3022     assert(prio != NoPriority, "A valid priority should be present");
3023   }
3024 
3025   // Push the Java priority down to the native thread; needs Threads_lock
3026   Thread::set_priority(this, prio);
3027 
3028   // Add the new thread to the Threads list and set it in motion.
3029   // We must have threads lock in order to call Threads::add.
3030   // It is crucial that we do not block before the thread is
3031   // added to the Threads list for if a GC happens, then the java_thread oop
3032   // will not be visited by GC.
3033   Threads::add(this);
3034 }
3035 
3036 oop JavaThread::current_park_blocker() {
3037   // Support for JSR-166 locks
3038   oop thread_oop = threadObj();
3039   if (thread_oop != NULL &&
3040       JDK_Version::current().supports_thread_park_blocker()) {
3041     return java_lang_Thread::park_blocker(thread_oop);
3042   }
3043   return NULL;
3044 }
3045 
3046 
3047 void JavaThread::print_stack_on(outputStream* st) {
3048   if (!has_last_Java_frame()) return;
3049   ResourceMark rm;
3050   HandleMark   hm;
3051 
3052   RegisterMap reg_map(this);
3053   vframe* start_vf = last_java_vframe(&reg_map);
3054   int count = 0;
3055   for (vframe* f = start_vf; f; f = f->sender() ) {
3056     if (f->is_java_frame()) {
3057       javaVFrame* jvf = javaVFrame::cast(f);
3058       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3059 
3060       // Print out lock information
3061       if (JavaMonitorsInStackTrace) {
3062         jvf->print_lock_info_on(st, count);
3063       }
3064     } else {
3065       // Ignore non-Java frames
3066     }
3067 
3068     // Bail-out case for too deep stacks
3069     count++;
3070     if (MaxJavaStackTraceDepth == count) return;
3071   }
3072 }
3073 
3074 
3075 // JVMTI PopFrame support
3076 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3077   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3078   if (in_bytes(size_in_bytes) != 0) {
3079     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3080     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3081     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3082   }
3083 }
3084 
3085 void* JavaThread::popframe_preserved_args() {
3086   return _popframe_preserved_args;
3087 }
3088 
3089 ByteSize JavaThread::popframe_preserved_args_size() {
3090   return in_ByteSize(_popframe_preserved_args_size);
3091 }
3092 
3093 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3094   int sz = in_bytes(popframe_preserved_args_size());
3095   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3096   return in_WordSize(sz / wordSize);
3097 }
3098 
3099 void JavaThread::popframe_free_preserved_args() {
3100   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3101   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3102   _popframe_preserved_args = NULL;
3103   _popframe_preserved_args_size = 0;
3104 }
3105 
3106 #ifndef PRODUCT
3107 
3108 void JavaThread::trace_frames() {
3109   tty->print_cr("[Describe stack]");
3110   int frame_no = 1;
3111   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3112     tty->print("  %d. ", frame_no++);
3113     fst.current()->print_value_on(tty,this);
3114     tty->cr();
3115   }
3116 }
3117 
3118 class PrintAndVerifyOopClosure: public OopClosure {
3119  protected:
3120   template <class T> inline void do_oop_work(T* p) {
3121     oop obj = oopDesc::load_decode_heap_oop(p);
3122     if (obj == NULL) return;
3123     tty->print(INTPTR_FORMAT ": ", p);
3124     if (obj->is_oop_or_null()) {
3125       if (obj->is_objArray()) {
3126         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3127       } else {
3128         obj->print();
3129       }
3130     } else {
3131       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3132     }
3133     tty->cr();
3134   }
3135  public:
3136   virtual void do_oop(oop* p) { do_oop_work(p); }
3137   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3138 };
3139 
3140 
3141 static void oops_print(frame* f, const RegisterMap *map) {
3142   PrintAndVerifyOopClosure print;
3143   f->print_value();
3144   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3145 }
3146 
3147 // Print our all the locations that contain oops and whether they are
3148 // valid or not.  This useful when trying to find the oldest frame
3149 // where an oop has gone bad since the frame walk is from youngest to
3150 // oldest.
3151 void JavaThread::trace_oops() {
3152   tty->print_cr("[Trace oops]");
3153   frames_do(oops_print);
3154 }
3155 
3156 
3157 #ifdef ASSERT
3158 // Print or validate the layout of stack frames
3159 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3160   ResourceMark rm;
3161   PRESERVE_EXCEPTION_MARK;
3162   FrameValues values;
3163   int frame_no = 0;
3164   for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3165     fst.current()->describe(values, ++frame_no);
3166     if (depth == frame_no) break;
3167   }
3168   if (validate_only) {
3169     values.validate();
3170   } else {
3171     tty->print_cr("[Describe stack layout]");
3172     values.print(this);
3173   }
3174 }
3175 #endif
3176 
3177 void JavaThread::trace_stack_from(vframe* start_vf) {
3178   ResourceMark rm;
3179   int vframe_no = 1;
3180   for (vframe* f = start_vf; f; f = f->sender() ) {
3181     if (f->is_java_frame()) {
3182       javaVFrame::cast(f)->print_activation(vframe_no++);
3183     } else {
3184       f->print();
3185     }
3186     if (vframe_no > StackPrintLimit) {
3187       tty->print_cr("...<more frames>...");
3188       return;
3189     }
3190   }
3191 }
3192 
3193 
3194 void JavaThread::trace_stack() {
3195   if (!has_last_Java_frame()) return;
3196   ResourceMark rm;
3197   HandleMark   hm;
3198   RegisterMap reg_map(this);
3199   trace_stack_from(last_java_vframe(&reg_map));
3200 }
3201 
3202 
3203 #endif // PRODUCT
3204 
3205 
3206 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3207   assert(reg_map != NULL, "a map must be given");
3208   frame f = last_frame();
3209   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3210     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3211   }
3212   return NULL;
3213 }
3214 
3215 
3216 Klass* JavaThread::security_get_caller_class(int depth) {
3217   vframeStream vfst(this);
3218   vfst.security_get_caller_frame(depth);
3219   if (!vfst.at_end()) {
3220     return vfst.method()->method_holder();
3221   }
3222   return NULL;
3223 }
3224 
3225 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3226   assert(thread->is_Compiler_thread(), "must be compiler thread");
3227   CompileBroker::compiler_thread_loop();
3228 }
3229 
3230 // Create a CompilerThread
3231 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3232 : JavaThread(&compiler_thread_entry) {
3233   _env   = NULL;
3234   _log   = NULL;
3235   _task  = NULL;
3236   _queue = queue;
3237   _counters = counters;
3238   _buffer_blob = NULL;
3239   _scanned_nmethod = NULL;
3240 
3241 #ifndef PRODUCT
3242   _ideal_graph_printer = NULL;
3243 #endif
3244 }
3245 
3246 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3247   JavaThread::oops_do(f, cld_f, cf);
3248   if (_scanned_nmethod != NULL && cf != NULL) {
3249     // Safepoints can occur when the sweeper is scanning an nmethod so
3250     // process it here to make sure it isn't unloaded in the middle of
3251     // a scan.
3252     cf->do_code_blob(_scanned_nmethod);
3253   }
3254 }
3255 
3256 // ======= Threads ========
3257 
3258 // The Threads class links together all active threads, and provides
3259 // operations over all threads.  It is protected by its own Mutex
3260 // lock, which is also used in other contexts to protect thread
3261 // operations from having the thread being operated on from exiting
3262 // and going away unexpectedly (e.g., safepoint synchronization)
3263 
3264 JavaThread* Threads::_thread_list = NULL;
3265 int         Threads::_number_of_threads = 0;
3266 int         Threads::_number_of_non_daemon_threads = 0;
3267 int         Threads::_return_code = 0;
3268 size_t      JavaThread::_stack_size_at_create = 0;
3269 #ifdef ASSERT
3270 bool        Threads::_vm_complete = false;
3271 #endif
3272 
3273 // All JavaThreads
3274 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3275 
3276 void os_stream();
3277 
3278 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3279 void Threads::threads_do(ThreadClosure* tc) {
3280   assert_locked_or_safepoint(Threads_lock);
3281   // ALL_JAVA_THREADS iterates through all JavaThreads
3282   ALL_JAVA_THREADS(p) {
3283     tc->do_thread(p);
3284   }
3285   // Someday we could have a table or list of all non-JavaThreads.
3286   // For now, just manually iterate through them.
3287   tc->do_thread(VMThread::vm_thread());
3288   Universe::heap()->gc_threads_do(tc);
3289   WatcherThread *wt = WatcherThread::watcher_thread();
3290   // Strictly speaking, the following NULL check isn't sufficient to make sure
3291   // the data for WatcherThread is still valid upon being examined. However,
3292   // considering that WatchThread terminates when the VM is on the way to
3293   // exit at safepoint, the chance of the above is extremely small. The right
3294   // way to prevent termination of WatcherThread would be to acquire
3295   // Terminator_lock, but we can't do that without violating the lock rank
3296   // checking in some cases.
3297   if (wt != NULL)
3298     tc->do_thread(wt);
3299 
3300   // If CompilerThreads ever become non-JavaThreads, add them here
3301 }
3302 
3303 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3304 
3305   extern void JDK_Version_init();
3306 
3307   // Check version
3308   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3309 
3310   // Initialize the output stream module
3311   ostream_init();
3312 
3313   // Process java launcher properties.
3314   Arguments::process_sun_java_launcher_properties(args);
3315 
3316   // Initialize the os module before using TLS
3317   os::init();
3318 
3319   // Initialize system properties.
3320   Arguments::init_system_properties();
3321 
3322   // So that JDK version can be used as a discrimintor when parsing arguments
3323   JDK_Version_init();
3324 
3325   // Update/Initialize System properties after JDK version number is known
3326   Arguments::init_version_specific_system_properties();
3327 
3328   // Parse arguments
3329   jint parse_result = Arguments::parse(args);
3330   if (parse_result != JNI_OK) return parse_result;
3331 
3332   if (PauseAtStartup) {
3333     os::pause();
3334   }
3335 
3336 #ifndef USDT2
3337   HS_DTRACE_PROBE(hotspot, vm__init__begin);
3338 #else /* USDT2 */
3339   HOTSPOT_VM_INIT_BEGIN();
3340 #endif /* USDT2 */
3341 
3342   // Record VM creation timing statistics
3343   TraceVmCreationTime create_vm_timer;
3344   create_vm_timer.start();
3345 
3346   // Timing (must come after argument parsing)
3347   TraceTime timer("Create VM", TraceStartupTime);
3348 
3349   // Initialize the os module after parsing the args
3350   jint os_init_2_result = os::init_2();
3351   if (os_init_2_result != JNI_OK) return os_init_2_result;
3352 
3353   jint adjust_after_os_result = Arguments::adjust_after_os();
3354   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3355 
3356   // intialize TLS
3357   ThreadLocalStorage::init();
3358 
3359   // Bootstrap native memory tracking, so it can start recording memory
3360   // activities before worker thread is started. This is the first phase
3361   // of bootstrapping, VM is currently running in single-thread mode.
3362   MemTracker::bootstrap_single_thread();
3363 
3364   // Initialize output stream logging
3365   ostream_init_log();
3366 
3367   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3368   // Must be before create_vm_init_agents()
3369   if (Arguments::init_libraries_at_startup()) {
3370     convert_vm_init_libraries_to_agents();
3371   }
3372 
3373   // Launch -agentlib/-agentpath and converted -Xrun agents
3374   if (Arguments::init_agents_at_startup()) {
3375     create_vm_init_agents();
3376   }
3377 
3378   // Initialize Threads state
3379   _thread_list = NULL;
3380   _number_of_threads = 0;
3381   _number_of_non_daemon_threads = 0;
3382 
3383   // Initialize global data structures and create system classes in heap
3384   vm_init_globals();
3385 
3386   // Attach the main thread to this os thread
3387   JavaThread* main_thread = new JavaThread();
3388   main_thread->set_thread_state(_thread_in_vm);
3389   // must do this before set_active_handles and initialize_thread_local_storage
3390   // Note: on solaris initialize_thread_local_storage() will (indirectly)
3391   // change the stack size recorded here to one based on the java thread
3392   // stacksize. This adjusted size is what is used to figure the placement
3393   // of the guard pages.
3394   main_thread->record_stack_base_and_size();
3395   main_thread->initialize_thread_local_storage();
3396 
3397   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3398 
3399   if (!main_thread->set_as_starting_thread()) {
3400     vm_shutdown_during_initialization(
3401       "Failed necessary internal allocation. Out of swap space");
3402     delete main_thread;
3403     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3404     return JNI_ENOMEM;
3405   }
3406 
3407   // Enable guard page *after* os::create_main_thread(), otherwise it would
3408   // crash Linux VM, see notes in os_linux.cpp.
3409   main_thread->create_stack_guard_pages();
3410 
3411   // Initialize Java-Level synchronization subsystem
3412   ObjectMonitor::Initialize() ;
3413 
3414   // Second phase of bootstrapping, VM is about entering multi-thread mode
3415   MemTracker::bootstrap_multi_thread();
3416 
3417   // Initialize global modules
3418   jint status = init_globals();
3419   if (status != JNI_OK) {
3420     delete main_thread;
3421     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3422     return status;
3423   }
3424 
3425   // Should be done after the heap is fully created
3426   main_thread->cache_global_variables();
3427 
3428   HandleMark hm;
3429 
3430   { MutexLocker mu(Threads_lock);
3431     Threads::add(main_thread);
3432   }
3433 
3434   // Any JVMTI raw monitors entered in onload will transition into
3435   // real raw monitor. VM is setup enough here for raw monitor enter.
3436   JvmtiExport::transition_pending_onload_raw_monitors();
3437 
3438   // Fully start NMT
3439   MemTracker::start();
3440 
3441   // Create the VMThread
3442   { TraceTime timer("Start VMThread", TraceStartupTime);
3443     VMThread::create();
3444     Thread* vmthread = VMThread::vm_thread();
3445 
3446     if (!os::create_thread(vmthread, os::vm_thread))
3447       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3448 
3449     // Wait for the VM thread to become ready, and VMThread::run to initialize
3450     // Monitors can have spurious returns, must always check another state flag
3451     {
3452       MutexLocker ml(Notify_lock);
3453       os::start_thread(vmthread);
3454       while (vmthread->active_handles() == NULL) {
3455         Notify_lock->wait();
3456       }
3457     }
3458   }
3459 
3460   assert (Universe::is_fully_initialized(), "not initialized");
3461   if (VerifyDuringStartup) {
3462     // Make sure we're starting with a clean slate.
3463     VM_Verify verify_op;
3464     VMThread::execute(&verify_op);
3465   }
3466 
3467   EXCEPTION_MARK;
3468 
3469   // At this point, the Universe is initialized, but we have not executed
3470   // any byte code.  Now is a good time (the only time) to dump out the
3471   // internal state of the JVM for sharing.
3472   if (DumpSharedSpaces) {
3473     MetaspaceShared::preload_and_dump(CHECK_0);
3474     ShouldNotReachHere();
3475   }
3476 
3477   // Always call even when there are not JVMTI environments yet, since environments
3478   // may be attached late and JVMTI must track phases of VM execution
3479   JvmtiExport::enter_start_phase();
3480 
3481   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3482   JvmtiExport::post_vm_start();
3483 
3484   {
3485     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3486 
3487     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3488       create_vm_init_libraries();
3489     }
3490 
3491     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3492 
3493     // Initialize java_lang.System (needed before creating the thread)
3494     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3495     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3496     Handle thread_group = create_initial_thread_group(CHECK_0);
3497     Universe::set_main_thread_group(thread_group());
3498     initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3499     oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3500     main_thread->set_threadObj(thread_object);
3501     // Set thread status to running since main thread has
3502     // been started and running.
3503     java_lang_Thread::set_thread_status(thread_object,
3504                                         java_lang_Thread::RUNNABLE);
3505 
3506     // The VM creates & returns objects of this class. Make sure it's initialized.
3507     initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3508 
3509     // The VM preresolves methods to these classes. Make sure that they get initialized
3510     initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3511     initialize_class(vmSymbols::java_lang_ref_Finalizer(),  CHECK_0);
3512     call_initializeSystemClass(CHECK_0);
3513 
3514     // get the Java runtime name after java.lang.System is initialized
3515     JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3516     JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3517 
3518     // an instance of OutOfMemory exception has been allocated earlier
3519     initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3520     initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3521     initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3522     initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3523     initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3524     initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3525     initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3526     initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3527   }
3528 
3529   // See        : bugid 4211085.
3530   // Background : the static initializer of java.lang.Compiler tries to read
3531   //              property"java.compiler" and read & write property "java.vm.info".
3532   //              When a security manager is installed through the command line
3533   //              option "-Djava.security.manager", the above properties are not
3534   //              readable and the static initializer for java.lang.Compiler fails
3535   //              resulting in a NoClassDefFoundError.  This can happen in any
3536   //              user code which calls methods in java.lang.Compiler.
3537   // Hack :       the hack is to pre-load and initialize this class, so that only
3538   //              system domains are on the stack when the properties are read.
3539   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3540   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3541   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3542   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3543   //              Once that is done, we should remove this hack.
3544   initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3545 
3546   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3547   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3548   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3549   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3550   // This should also be taken out as soon as 4211383 gets fixed.
3551   reset_vm_info_property(CHECK_0);
3552 
3553   quicken_jni_functions();
3554 
3555   // Must be run after init_ft which initializes ft_enabled
3556   if (TRACE_INITIALIZE() != JNI_OK) {
3557     vm_exit_during_initialization("Failed to initialize tracing backend");
3558   }
3559 
3560   // Set flag that basic initialization has completed. Used by exceptions and various
3561   // debug stuff, that does not work until all basic classes have been initialized.
3562   set_init_completed();
3563 
3564 #ifndef USDT2
3565   HS_DTRACE_PROBE(hotspot, vm__init__end);
3566 #else /* USDT2 */
3567   HOTSPOT_VM_INIT_END();
3568 #endif /* USDT2 */
3569 
3570   // record VM initialization completion time
3571 #if INCLUDE_MANAGEMENT
3572   Management::record_vm_init_completed();
3573 #endif // INCLUDE_MANAGEMENT
3574 
3575   // Compute system loader. Note that this has to occur after set_init_completed, since
3576   // valid exceptions may be thrown in the process.
3577   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3578   // set_init_completed has just been called, causing exceptions not to be shortcut
3579   // anymore. We call vm_exit_during_initialization directly instead.
3580   SystemDictionary::compute_java_system_loader(THREAD);
3581   if (HAS_PENDING_EXCEPTION) {
3582     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3583   }
3584 
3585 #if INCLUDE_ALL_GCS
3586   // Support for ConcurrentMarkSweep. This should be cleaned up
3587   // and better encapsulated. The ugly nested if test would go away
3588   // once things are properly refactored. XXX YSR
3589   if (UseConcMarkSweepGC || UseG1GC) {
3590     if (UseConcMarkSweepGC) {
3591       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3592     } else {
3593       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3594     }
3595     if (HAS_PENDING_EXCEPTION) {
3596       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3597     }
3598   }
3599 #endif // INCLUDE_ALL_GCS
3600 
3601   // Always call even when there are not JVMTI environments yet, since environments
3602   // may be attached late and JVMTI must track phases of VM execution
3603   JvmtiExport::enter_live_phase();
3604 
3605   // Signal Dispatcher needs to be started before VMInit event is posted
3606   os::signal_init();
3607 
3608   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3609   if (!DisableAttachMechanism) {
3610     AttachListener::vm_start();
3611     if (StartAttachListener || AttachListener::init_at_startup()) {
3612       AttachListener::init();
3613     }
3614   }
3615 
3616   // Launch -Xrun agents
3617   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3618   // back-end can launch with -Xdebug -Xrunjdwp.
3619   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3620     create_vm_init_libraries();
3621   }
3622 
3623   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3624   JvmtiExport::post_vm_initialized();
3625 
3626   if (TRACE_START() != JNI_OK) {
3627     vm_exit_during_initialization("Failed to start tracing backend.");
3628   }
3629 
3630   if (CleanChunkPoolAsync) {
3631     Chunk::start_chunk_pool_cleaner_task();
3632   }
3633 
3634   // initialize compiler(s)
3635 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3636   CompileBroker::compilation_init();
3637 #endif
3638 
3639   if (EnableInvokeDynamic) {
3640     // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3641     // It is done after compilers are initialized, because otherwise compilations of
3642     // signature polymorphic MH intrinsics can be missed
3643     // (see SystemDictionary::find_method_handle_intrinsic).
3644     initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3645     initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3646     initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3647   }
3648 
3649 #if INCLUDE_MANAGEMENT
3650   Management::initialize(THREAD);
3651 #endif // INCLUDE_MANAGEMENT
3652 
3653   if (HAS_PENDING_EXCEPTION) {
3654     // management agent fails to start possibly due to
3655     // configuration problem and is responsible for printing
3656     // stack trace if appropriate. Simply exit VM.
3657     vm_exit(1);
3658   }
3659 
3660   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3661   if (MemProfiling)                   MemProfiler::engage();
3662   StatSampler::engage();
3663   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3664 
3665   BiasedLocking::init();
3666 
3667   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3668     call_postVMInitHook(THREAD);
3669     // The Java side of PostVMInitHook.run must deal with all
3670     // exceptions and provide means of diagnosis.
3671     if (HAS_PENDING_EXCEPTION) {
3672       CLEAR_PENDING_EXCEPTION;
3673     }
3674   }
3675 
3676   {
3677       MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3678       // Make sure the watcher thread can be started by WatcherThread::start()
3679       // or by dynamic enrollment.
3680       WatcherThread::make_startable();
3681       // Start up the WatcherThread if there are any periodic tasks
3682       // NOTE:  All PeriodicTasks should be registered by now. If they
3683       //   aren't, late joiners might appear to start slowly (we might
3684       //   take a while to process their first tick).
3685       if (PeriodicTask::num_tasks() > 0) {
3686           WatcherThread::start();
3687       }
3688   }
3689 
3690   // Give os specific code one last chance to start
3691   os::init_3();
3692 
3693   create_vm_timer.end();
3694 #ifdef ASSERT
3695   _vm_complete = true;
3696 #endif
3697   return JNI_OK;
3698 }
3699 
3700 // type for the Agent_OnLoad and JVM_OnLoad entry points
3701 extern "C" {
3702   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3703 }
3704 // Find a command line agent library and return its entry point for
3705 //         -agentlib:  -agentpath:   -Xrun
3706 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3707 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3708   OnLoadEntry_t on_load_entry = NULL;
3709   void *library = agent->os_lib();  // check if we have looked it up before
3710 
3711   if (library == NULL) {
3712     char buffer[JVM_MAXPATHLEN];
3713     char ebuf[1024];
3714     const char *name = agent->name();
3715     const char *msg = "Could not find agent library ";
3716 
3717     if (agent->is_absolute_path()) {
3718       library = os::dll_load(name, ebuf, sizeof ebuf);
3719       if (library == NULL) {
3720         const char *sub_msg = " in absolute path, with error: ";
3721         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3722         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3723         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3724         // If we can't find the agent, exit.
3725         vm_exit_during_initialization(buf, NULL);
3726         FREE_C_HEAP_ARRAY(char, buf, mtThread);
3727       }
3728     } else {
3729       // Try to load the agent from the standard dll directory
3730       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3731                              name)) {
3732         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3733       }
3734       if (library == NULL) { // Try the local directory
3735         char ns[1] = {0};
3736         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3737           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3738         }
3739         if (library == NULL) {
3740           const char *sub_msg = " on the library path, with error: ";
3741           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3742           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3743           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3744           // If we can't find the agent, exit.
3745           vm_exit_during_initialization(buf, NULL);
3746           FREE_C_HEAP_ARRAY(char, buf, mtThread);
3747         }
3748       }
3749     }
3750     agent->set_os_lib(library);
3751   }
3752 
3753   // Find the OnLoad function.
3754   for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3755     on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3756     if (on_load_entry != NULL) break;
3757   }
3758   return on_load_entry;
3759 }
3760 
3761 // Find the JVM_OnLoad entry point
3762 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3763   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3764   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3765 }
3766 
3767 // Find the Agent_OnLoad entry point
3768 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3769   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3770   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3771 }
3772 
3773 // For backwards compatibility with -Xrun
3774 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3775 // treated like -agentpath:
3776 // Must be called before agent libraries are created
3777 void Threads::convert_vm_init_libraries_to_agents() {
3778   AgentLibrary* agent;
3779   AgentLibrary* next;
3780 
3781   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3782     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3783     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3784 
3785     // If there is an JVM_OnLoad function it will get called later,
3786     // otherwise see if there is an Agent_OnLoad
3787     if (on_load_entry == NULL) {
3788       on_load_entry = lookup_agent_on_load(agent);
3789       if (on_load_entry != NULL) {
3790         // switch it to the agent list -- so that Agent_OnLoad will be called,
3791         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3792         Arguments::convert_library_to_agent(agent);
3793       } else {
3794         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3795       }
3796     }
3797   }
3798 }
3799 
3800 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3801 // Invokes Agent_OnLoad
3802 // Called very early -- before JavaThreads exist
3803 void Threads::create_vm_init_agents() {
3804   extern struct JavaVM_ main_vm;
3805   AgentLibrary* agent;
3806 
3807   JvmtiExport::enter_onload_phase();
3808 
3809   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3810     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3811 
3812     if (on_load_entry != NULL) {
3813       // Invoke the Agent_OnLoad function
3814       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3815       if (err != JNI_OK) {
3816         vm_exit_during_initialization("agent library failed to init", agent->name());
3817       }
3818     } else {
3819       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3820     }
3821   }
3822   JvmtiExport::enter_primordial_phase();
3823 }
3824 
3825 extern "C" {
3826   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3827 }
3828 
3829 void Threads::shutdown_vm_agents() {
3830   // Send any Agent_OnUnload notifications
3831   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3832   extern struct JavaVM_ main_vm;
3833   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3834 
3835     // Find the Agent_OnUnload function.
3836     for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3837       Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3838                os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3839 
3840       // Invoke the Agent_OnUnload function
3841       if (unload_entry != NULL) {
3842         JavaThread* thread = JavaThread::current();
3843         ThreadToNativeFromVM ttn(thread);
3844         HandleMark hm(thread);
3845         (*unload_entry)(&main_vm);
3846         break;
3847       }
3848     }
3849   }
3850 }
3851 
3852 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3853 // Invokes JVM_OnLoad
3854 void Threads::create_vm_init_libraries() {
3855   extern struct JavaVM_ main_vm;
3856   AgentLibrary* agent;
3857 
3858   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3859     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3860 
3861     if (on_load_entry != NULL) {
3862       // Invoke the JVM_OnLoad function
3863       JavaThread* thread = JavaThread::current();
3864       ThreadToNativeFromVM ttn(thread);
3865       HandleMark hm(thread);
3866       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3867       if (err != JNI_OK) {
3868         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3869       }
3870     } else {
3871       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3872     }
3873   }
3874 }
3875 
3876 // Last thread running calls java.lang.Shutdown.shutdown()
3877 void JavaThread::invoke_shutdown_hooks() {
3878   HandleMark hm(this);
3879 
3880   // We could get here with a pending exception, if so clear it now.
3881   if (this->has_pending_exception()) {
3882     this->clear_pending_exception();
3883   }
3884 
3885   EXCEPTION_MARK;
3886   Klass* k =
3887     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3888                                       THREAD);
3889   if (k != NULL) {
3890     // SystemDictionary::resolve_or_null will return null if there was
3891     // an exception.  If we cannot load the Shutdown class, just don't
3892     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3893     // and finalizers (if runFinalizersOnExit is set) won't be run.
3894     // Note that if a shutdown hook was registered or runFinalizersOnExit
3895     // was called, the Shutdown class would have already been loaded
3896     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3897     instanceKlassHandle shutdown_klass (THREAD, k);
3898     JavaValue result(T_VOID);
3899     JavaCalls::call_static(&result,
3900                            shutdown_klass,
3901                            vmSymbols::shutdown_method_name(),
3902                            vmSymbols::void_method_signature(),
3903                            THREAD);
3904   }
3905   CLEAR_PENDING_EXCEPTION;
3906 }
3907 
3908 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3909 // the program falls off the end of main(). Another VM exit path is through
3910 // vm_exit() when the program calls System.exit() to return a value or when
3911 // there is a serious error in VM. The two shutdown paths are not exactly
3912 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3913 // and VM_Exit op at VM level.
3914 //
3915 // Shutdown sequence:
3916 //   + Shutdown native memory tracking if it is on
3917 //   + Wait until we are the last non-daemon thread to execute
3918 //     <-- every thing is still working at this moment -->
3919 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3920 //        shutdown hooks, run finalizers if finalization-on-exit
3921 //   + Call before_exit(), prepare for VM exit
3922 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3923 //        currently the only user of this mechanism is File.deleteOnExit())
3924 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3925 //        post thread end and vm death events to JVMTI,
3926 //        stop signal thread
3927 //   + Call JavaThread::exit(), it will:
3928 //      > release JNI handle blocks, remove stack guard pages
3929 //      > remove this thread from Threads list
3930 //     <-- no more Java code from this thread after this point -->
3931 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3932 //     the compiler threads at safepoint
3933 //     <-- do not use anything that could get blocked by Safepoint -->
3934 //   + Disable tracing at JNI/JVM barriers
3935 //   + Set _vm_exited flag for threads that are still running native code
3936 //   + Delete this thread
3937 //   + Call exit_globals()
3938 //      > deletes tty
3939 //      > deletes PerfMemory resources
3940 //   + Return to caller
3941 
3942 bool Threads::destroy_vm() {
3943   JavaThread* thread = JavaThread::current();
3944 
3945 #ifdef ASSERT
3946   _vm_complete = false;
3947 #endif
3948   // Wait until we are the last non-daemon thread to execute
3949   { MutexLocker nu(Threads_lock);
3950     while (Threads::number_of_non_daemon_threads() > 1 )
3951       // This wait should make safepoint checks, wait without a timeout,
3952       // and wait as a suspend-equivalent condition.
3953       //
3954       // Note: If the FlatProfiler is running and this thread is waiting
3955       // for another non-daemon thread to finish, then the FlatProfiler
3956       // is waiting for the external suspend request on this thread to
3957       // complete. wait_for_ext_suspend_completion() will eventually
3958       // timeout, but that takes time. Making this wait a suspend-
3959       // equivalent condition solves that timeout problem.
3960       //
3961       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3962                          Mutex::_as_suspend_equivalent_flag);
3963   }
3964 
3965   // Hang forever on exit if we are reporting an error.
3966   if (ShowMessageBoxOnError && is_error_reported()) {
3967     os::infinite_sleep();
3968   }
3969   os::wait_for_keypress_at_exit();
3970 
3971   if (JDK_Version::is_jdk12x_version()) {
3972     // We are the last thread running, so check if finalizers should be run.
3973     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3974     HandleMark rm(thread);
3975     Universe::run_finalizers_on_exit();
3976   } else {
3977     // run Java level shutdown hooks
3978     thread->invoke_shutdown_hooks();
3979   }
3980 
3981   before_exit(thread);
3982 
3983   thread->exit(true);
3984 
3985   // Stop VM thread.
3986   {
3987     // 4945125 The vm thread comes to a safepoint during exit.
3988     // GC vm_operations can get caught at the safepoint, and the
3989     // heap is unparseable if they are caught. Grab the Heap_lock
3990     // to prevent this. The GC vm_operations will not be able to
3991     // queue until after the vm thread is dead.
3992     // After this point, we'll never emerge out of the safepoint before
3993     // the VM exits, so concurrent GC threads do not need to be explicitly
3994     // stopped; they remain inactive until the process exits.
3995     // Note: some concurrent G1 threads may be running during a safepoint,
3996     // but these will not be accessing the heap, just some G1-specific side
3997     // data structures that are not accessed by any other threads but them
3998     // after this point in a terminal safepoint.
3999 
4000     MutexLocker ml(Heap_lock);
4001 
4002     VMThread::wait_for_vm_thread_exit();
4003     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4004     VMThread::destroy();
4005   }
4006 
4007   // clean up ideal graph printers
4008 #if defined(COMPILER2) && !defined(PRODUCT)
4009   IdealGraphPrinter::clean_up();
4010 #endif
4011 
4012   // Now, all Java threads are gone except daemon threads. Daemon threads
4013   // running Java code or in VM are stopped by the Safepoint. However,
4014   // daemon threads executing native code are still running.  But they
4015   // will be stopped at native=>Java/VM barriers. Note that we can't
4016   // simply kill or suspend them, as it is inherently deadlock-prone.
4017 
4018 #ifndef PRODUCT
4019   // disable function tracing at JNI/JVM barriers
4020   TraceJNICalls = false;
4021   TraceJVMCalls = false;
4022   TraceRuntimeCalls = false;
4023 #endif
4024 
4025   VM_Exit::set_vm_exited();
4026 
4027   notify_vm_shutdown();
4028 
4029   delete thread;
4030 
4031   // exit_globals() will delete tty
4032   exit_globals();
4033 
4034   return true;
4035 }
4036 
4037 
4038 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4039   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4040   return is_supported_jni_version(version);
4041 }
4042 
4043 
4044 jboolean Threads::is_supported_jni_version(jint version) {
4045   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4046   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4047   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4048   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4049   return JNI_FALSE;
4050 }
4051 
4052 
4053 void Threads::add(JavaThread* p, bool force_daemon) {
4054   // The threads lock must be owned at this point
4055   assert_locked_or_safepoint(Threads_lock);
4056 
4057   // See the comment for this method in thread.hpp for its purpose and
4058   // why it is called here.
4059   p->initialize_queues();
4060   p->set_next(_thread_list);
4061   _thread_list = p;
4062   _number_of_threads++;
4063   oop threadObj = p->threadObj();
4064   bool daemon = true;
4065   // Bootstrapping problem: threadObj can be null for initial
4066   // JavaThread (or for threads attached via JNI)
4067   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4068     _number_of_non_daemon_threads++;
4069     daemon = false;
4070   }
4071 
4072   p->set_safepoint_visible(true);
4073 
4074   ThreadService::add_thread(p, daemon);
4075 
4076   // Possible GC point.
4077   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4078 }
4079 
4080 void Threads::remove(JavaThread* p) {
4081   // Extra scope needed for Thread_lock, so we can check
4082   // that we do not remove thread without safepoint code notice
4083   { MutexLocker ml(Threads_lock);
4084 
4085     assert(includes(p), "p must be present");
4086 
4087     JavaThread* current = _thread_list;
4088     JavaThread* prev    = NULL;
4089 
4090     while (current != p) {
4091       prev    = current;
4092       current = current->next();
4093     }
4094 
4095     if (prev) {
4096       prev->set_next(current->next());
4097     } else {
4098       _thread_list = p->next();
4099     }
4100     _number_of_threads--;
4101     oop threadObj = p->threadObj();
4102     bool daemon = true;
4103     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4104       _number_of_non_daemon_threads--;
4105       daemon = false;
4106 
4107       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4108       // on destroy_vm will wake up.
4109       if (number_of_non_daemon_threads() == 1)
4110         Threads_lock->notify_all();
4111     }
4112     ThreadService::remove_thread(p, daemon);
4113 
4114     // Make sure that safepoint code disregard this thread. This is needed since
4115     // the thread might mess around with locks after this point. This can cause it
4116     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4117     // of this thread since it is removed from the queue.
4118     p->set_terminated_value();
4119 
4120     // Now, this thread is not visible to safepoint
4121     p->set_safepoint_visible(false);
4122     // once the thread becomes safepoint invisible, we can not use its per-thread
4123     // recorder. And Threads::do_threads() no longer walks this thread, so we have
4124     // to release its per-thread recorder here.
4125     MemTracker::thread_exiting(p);
4126   } // unlock Threads_lock
4127 
4128   // Since Events::log uses a lock, we grab it outside the Threads_lock
4129   Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4130 }
4131 
4132 // Threads_lock must be held when this is called (or must be called during a safepoint)
4133 bool Threads::includes(JavaThread* p) {
4134   assert(Threads_lock->is_locked(), "sanity check");
4135   ALL_JAVA_THREADS(q) {
4136     if (q == p ) {
4137       return true;
4138     }
4139   }
4140   return false;
4141 }
4142 
4143 // Operations on the Threads list for GC.  These are not explicitly locked,
4144 // but the garbage collector must provide a safe context for them to run.
4145 // In particular, these things should never be called when the Threads_lock
4146 // is held by some other thread. (Note: the Safepoint abstraction also
4147 // uses the Threads_lock to gurantee this property. It also makes sure that
4148 // all threads gets blocked when exiting or starting).
4149 
4150 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4151   ALL_JAVA_THREADS(p) {
4152     p->oops_do(f, cld_f, cf);
4153   }
4154   VMThread::vm_thread()->oops_do(f, cld_f, cf);
4155 }
4156 
4157 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4158   // Introduce a mechanism allowing parallel threads to claim threads as
4159   // root groups.  Overhead should be small enough to use all the time,
4160   // even in sequential code.
4161   SharedHeap* sh = SharedHeap::heap();
4162   // Cannot yet substitute active_workers for n_par_threads
4163   // because of G1CollectedHeap::verify() use of
4164   // SharedHeap::process_strong_roots().  n_par_threads == 0 will
4165   // turn off parallelism in process_strong_roots while active_workers
4166   // is being used for parallelism elsewhere.
4167   bool is_par = sh->n_par_threads() > 0;
4168   assert(!is_par ||
4169          (SharedHeap::heap()->n_par_threads() ==
4170           SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4171   int cp = SharedHeap::heap()->strong_roots_parity();
4172   ALL_JAVA_THREADS(p) {
4173     if (p->claim_oops_do(is_par, cp)) {
4174       p->oops_do(f, cld_f, cf);
4175     }
4176   }
4177   VMThread* vmt = VMThread::vm_thread();
4178   if (vmt->claim_oops_do(is_par, cp)) {
4179     vmt->oops_do(f, cld_f, cf);
4180   }
4181 }
4182 
4183 #if INCLUDE_ALL_GCS
4184 // Used by ParallelScavenge
4185 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4186   ALL_JAVA_THREADS(p) {
4187     q->enqueue(new ThreadRootsTask(p));
4188   }
4189   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4190 }
4191 
4192 // Used by Parallel Old
4193 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4194   ALL_JAVA_THREADS(p) {
4195     q->enqueue(new ThreadRootsMarkingTask(p));
4196   }
4197   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4198 }
4199 #endif // INCLUDE_ALL_GCS
4200 
4201 void Threads::nmethods_do(CodeBlobClosure* cf) {
4202   ALL_JAVA_THREADS(p) {
4203     p->nmethods_do(cf);
4204   }
4205   VMThread::vm_thread()->nmethods_do(cf);
4206 }
4207 
4208 void Threads::metadata_do(void f(Metadata*)) {
4209   ALL_JAVA_THREADS(p) {
4210     p->metadata_do(f);
4211   }
4212 }
4213 
4214 void Threads::gc_epilogue() {
4215   ALL_JAVA_THREADS(p) {
4216     p->gc_epilogue();
4217   }
4218 }
4219 
4220 void Threads::gc_prologue() {
4221   ALL_JAVA_THREADS(p) {
4222     p->gc_prologue();
4223   }
4224 }
4225 
4226 void Threads::deoptimized_wrt_marked_nmethods() {
4227   ALL_JAVA_THREADS(p) {
4228     p->deoptimized_wrt_marked_nmethods();
4229   }
4230 }
4231 
4232 
4233 // Get count Java threads that are waiting to enter the specified monitor.
4234 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4235   address monitor, bool doLock) {
4236   assert(doLock || SafepointSynchronize::is_at_safepoint(),
4237     "must grab Threads_lock or be at safepoint");
4238   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4239 
4240   int i = 0;
4241   {
4242     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4243     ALL_JAVA_THREADS(p) {
4244       if (p->is_Compiler_thread()) continue;
4245 
4246       address pending = (address)p->current_pending_monitor();
4247       if (pending == monitor) {             // found a match
4248         if (i < count) result->append(p);   // save the first count matches
4249         i++;
4250       }
4251     }
4252   }
4253   return result;
4254 }
4255 
4256 
4257 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4258   assert(doLock ||
4259          Threads_lock->owned_by_self() ||
4260          SafepointSynchronize::is_at_safepoint(),
4261          "must grab Threads_lock or be at safepoint");
4262 
4263   // NULL owner means not locked so we can skip the search
4264   if (owner == NULL) return NULL;
4265 
4266   {
4267     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4268     ALL_JAVA_THREADS(p) {
4269       // first, see if owner is the address of a Java thread
4270       if (owner == (address)p) return p;
4271     }
4272   }
4273   // Cannot assert on lack of success here since this function may be
4274   // used by code that is trying to report useful problem information
4275   // like deadlock detection.
4276   if (UseHeavyMonitors) return NULL;
4277 
4278   //
4279   // If we didn't find a matching Java thread and we didn't force use of
4280   // heavyweight monitors, then the owner is the stack address of the
4281   // Lock Word in the owning Java thread's stack.
4282   //
4283   JavaThread* the_owner = NULL;
4284   {
4285     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4286     ALL_JAVA_THREADS(q) {
4287       if (q->is_lock_owned(owner)) {
4288         the_owner = q;
4289         break;
4290       }
4291     }
4292   }
4293   // cannot assert on lack of success here; see above comment
4294   return the_owner;
4295 }
4296 
4297 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4298 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4299   char buf[32];
4300   st->print_cr(os::local_time_string(buf, sizeof(buf)));
4301 
4302   st->print_cr("Full thread dump %s (%s %s):",
4303                 Abstract_VM_Version::vm_name(),
4304                 Abstract_VM_Version::vm_release(),
4305                 Abstract_VM_Version::vm_info_string()
4306                );
4307   st->cr();
4308 
4309 #if INCLUDE_ALL_GCS
4310   // Dump concurrent locks
4311   ConcurrentLocksDump concurrent_locks;
4312   if (print_concurrent_locks) {
4313     concurrent_locks.dump_at_safepoint();
4314   }
4315 #endif // INCLUDE_ALL_GCS
4316 
4317   ALL_JAVA_THREADS(p) {
4318     ResourceMark rm;
4319     p->print_on(st);
4320     if (print_stacks) {
4321       if (internal_format) {
4322         p->trace_stack();
4323       } else {
4324         p->print_stack_on(st);
4325       }
4326     }
4327     st->cr();
4328 #if INCLUDE_ALL_GCS
4329     if (print_concurrent_locks) {
4330       concurrent_locks.print_locks_on(p, st);
4331     }
4332 #endif // INCLUDE_ALL_GCS
4333   }
4334 
4335   VMThread::vm_thread()->print_on(st);
4336   st->cr();
4337   Universe::heap()->print_gc_threads_on(st);
4338   WatcherThread* wt = WatcherThread::watcher_thread();
4339   if (wt != NULL) {
4340     wt->print_on(st);
4341     st->cr();
4342   }
4343   CompileBroker::print_compiler_threads_on(st);
4344   st->flush();
4345 }
4346 
4347 // Threads::print_on_error() is called by fatal error handler. It's possible
4348 // that VM is not at safepoint and/or current thread is inside signal handler.
4349 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4350 // memory (even in resource area), it might deadlock the error handler.
4351 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4352   bool found_current = false;
4353   st->print_cr("Java Threads: ( => current thread )");
4354   ALL_JAVA_THREADS(thread) {
4355     bool is_current = (current == thread);
4356     found_current = found_current || is_current;
4357 
4358     st->print("%s", is_current ? "=>" : "  ");
4359 
4360     st->print(PTR_FORMAT, thread);
4361     st->print(" ");
4362     thread->print_on_error(st, buf, buflen);
4363     st->cr();
4364   }
4365   st->cr();
4366 
4367   st->print_cr("Other Threads:");
4368   if (VMThread::vm_thread()) {
4369     bool is_current = (current == VMThread::vm_thread());
4370     found_current = found_current || is_current;
4371     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
4372 
4373     st->print(PTR_FORMAT, VMThread::vm_thread());
4374     st->print(" ");
4375     VMThread::vm_thread()->print_on_error(st, buf, buflen);
4376     st->cr();
4377   }
4378   WatcherThread* wt = WatcherThread::watcher_thread();
4379   if (wt != NULL) {
4380     bool is_current = (current == wt);
4381     found_current = found_current || is_current;
4382     st->print("%s", is_current ? "=>" : "  ");
4383 
4384     st->print(PTR_FORMAT, wt);
4385     st->print(" ");
4386     wt->print_on_error(st, buf, buflen);
4387     st->cr();
4388   }
4389   if (!found_current) {
4390     st->cr();
4391     st->print("=>" PTR_FORMAT " (exited) ", current);
4392     current->print_on_error(st, buf, buflen);
4393     st->cr();
4394   }
4395 }
4396 
4397 // Internal SpinLock and Mutex
4398 // Based on ParkEvent
4399 
4400 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4401 //
4402 // We employ SpinLocks _only for low-contention, fixed-length
4403 // short-duration critical sections where we're concerned
4404 // about native mutex_t or HotSpot Mutex:: latency.
4405 // The mux construct provides a spin-then-block mutual exclusion
4406 // mechanism.
4407 //
4408 // Testing has shown that contention on the ListLock guarding gFreeList
4409 // is common.  If we implement ListLock as a simple SpinLock it's common
4410 // for the JVM to devolve to yielding with little progress.  This is true
4411 // despite the fact that the critical sections protected by ListLock are
4412 // extremely short.
4413 //
4414 // TODO-FIXME: ListLock should be of type SpinLock.
4415 // We should make this a 1st-class type, integrated into the lock
4416 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4417 // should have sufficient padding to avoid false-sharing and excessive
4418 // cache-coherency traffic.
4419 
4420 
4421 typedef volatile int SpinLockT ;
4422 
4423 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4424   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4425      return ;   // normal fast-path return
4426   }
4427 
4428   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4429   TEVENT (SpinAcquire - ctx) ;
4430   int ctr = 0 ;
4431   int Yields = 0 ;
4432   for (;;) {
4433      while (*adr != 0) {
4434         ++ctr ;
4435         if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4436            if (Yields > 5) {
4437              // Consider using a simple NakedSleep() instead.
4438              // Then SpinAcquire could be called by non-JVM threads
4439              Thread::current()->_ParkEvent->park(1) ;
4440            } else {
4441              os::NakedYield() ;
4442              ++Yields ;
4443            }
4444         } else {
4445            SpinPause() ;
4446         }
4447      }
4448      if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4449   }
4450 }
4451 
4452 void Thread::SpinRelease (volatile int * adr) {
4453   assert (*adr != 0, "invariant") ;
4454   OrderAccess::fence() ;      // guarantee at least release consistency.
4455   // Roach-motel semantics.
4456   // It's safe if subsequent LDs and STs float "up" into the critical section,
4457   // but prior LDs and STs within the critical section can't be allowed
4458   // to reorder or float past the ST that releases the lock.
4459   *adr = 0 ;
4460 }
4461 
4462 // muxAcquire and muxRelease:
4463 //
4464 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4465 //    The LSB of the word is set IFF the lock is held.
4466 //    The remainder of the word points to the head of a singly-linked list
4467 //    of threads blocked on the lock.
4468 //
4469 // *  The current implementation of muxAcquire-muxRelease uses its own
4470 //    dedicated Thread._MuxEvent instance.  If we're interested in
4471 //    minimizing the peak number of extant ParkEvent instances then
4472 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4473 //    as certain invariants were satisfied.  Specifically, care would need
4474 //    to be taken with regards to consuming unpark() "permits".
4475 //    A safe rule of thumb is that a thread would never call muxAcquire()
4476 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4477 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4478 //    consume an unpark() permit intended for monitorenter, for instance.
4479 //    One way around this would be to widen the restricted-range semaphore
4480 //    implemented in park().  Another alternative would be to provide
4481 //    multiple instances of the PlatformEvent() for each thread.  One
4482 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4483 //
4484 // *  Usage:
4485 //    -- Only as leaf locks
4486 //    -- for short-term locking only as muxAcquire does not perform
4487 //       thread state transitions.
4488 //
4489 // Alternatives:
4490 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4491 //    but with parking or spin-then-park instead of pure spinning.
4492 // *  Use Taura-Oyama-Yonenzawa locks.
4493 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4494 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4495 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4496 //    acquiring threads use timers (ParkTimed) to detect and recover from
4497 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4498 //    boundaries by using placement-new.
4499 // *  Augment MCS with advisory back-link fields maintained with CAS().
4500 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4501 //    The validity of the backlinks must be ratified before we trust the value.
4502 //    If the backlinks are invalid the exiting thread must back-track through the
4503 //    the forward links, which are always trustworthy.
4504 // *  Add a successor indication.  The LockWord is currently encoded as
4505 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4506 //    to provide the usual futile-wakeup optimization.
4507 //    See RTStt for details.
4508 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4509 //
4510 
4511 
4512 typedef volatile intptr_t MutexT ;      // Mux Lock-word
4513 enum MuxBits { LOCKBIT = 1 } ;
4514 
4515 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4516   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4517   if (w == 0) return ;
4518   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4519      return ;
4520   }
4521 
4522   TEVENT (muxAcquire - Contention) ;
4523   ParkEvent * const Self = Thread::current()->_MuxEvent ;
4524   assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4525   for (;;) {
4526      int its = (os::is_MP() ? 100 : 0) + 1 ;
4527 
4528      // Optional spin phase: spin-then-park strategy
4529      while (--its >= 0) {
4530        w = *Lock ;
4531        if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4532           return ;
4533        }
4534      }
4535 
4536      Self->reset() ;
4537      Self->OnList = intptr_t(Lock) ;
4538      // The following fence() isn't _strictly necessary as the subsequent
4539      // CAS() both serializes execution and ratifies the fetched *Lock value.
4540      OrderAccess::fence();
4541      for (;;) {
4542         w = *Lock ;
4543         if ((w & LOCKBIT) == 0) {
4544             if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4545                 Self->OnList = 0 ;   // hygiene - allows stronger asserts
4546                 return ;
4547             }
4548             continue ;      // Interference -- *Lock changed -- Just retry
4549         }
4550         assert (w & LOCKBIT, "invariant") ;
4551         Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4552         if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4553      }
4554 
4555      while (Self->OnList != 0) {
4556         Self->park() ;
4557      }
4558   }
4559 }
4560 
4561 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4562   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4563   if (w == 0) return ;
4564   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4565     return ;
4566   }
4567 
4568   TEVENT (muxAcquire - Contention) ;
4569   ParkEvent * ReleaseAfter = NULL ;
4570   if (ev == NULL) {
4571     ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4572   }
4573   assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4574   for (;;) {
4575     guarantee (ev->OnList == 0, "invariant") ;
4576     int its = (os::is_MP() ? 100 : 0) + 1 ;
4577 
4578     // Optional spin phase: spin-then-park strategy
4579     while (--its >= 0) {
4580       w = *Lock ;
4581       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4582         if (ReleaseAfter != NULL) {
4583           ParkEvent::Release (ReleaseAfter) ;
4584         }
4585         return ;
4586       }
4587     }
4588 
4589     ev->reset() ;
4590     ev->OnList = intptr_t(Lock) ;
4591     // The following fence() isn't _strictly necessary as the subsequent
4592     // CAS() both serializes execution and ratifies the fetched *Lock value.
4593     OrderAccess::fence();
4594     for (;;) {
4595       w = *Lock ;
4596       if ((w & LOCKBIT) == 0) {
4597         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4598           ev->OnList = 0 ;
4599           // We call ::Release while holding the outer lock, thus
4600           // artificially lengthening the critical section.
4601           // Consider deferring the ::Release() until the subsequent unlock(),
4602           // after we've dropped the outer lock.
4603           if (ReleaseAfter != NULL) {
4604             ParkEvent::Release (ReleaseAfter) ;
4605           }
4606           return ;
4607         }
4608         continue ;      // Interference -- *Lock changed -- Just retry
4609       }
4610       assert (w & LOCKBIT, "invariant") ;
4611       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4612       if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4613     }
4614 
4615     while (ev->OnList != 0) {
4616       ev->park() ;
4617     }
4618   }
4619 }
4620 
4621 // Release() must extract a successor from the list and then wake that thread.
4622 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4623 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4624 // Release() would :
4625 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4626 // (B) Extract a successor from the private list "in-hand"
4627 // (C) attempt to CAS() the residual back into *Lock over null.
4628 //     If there were any newly arrived threads and the CAS() would fail.
4629 //     In that case Release() would detach the RATs, re-merge the list in-hand
4630 //     with the RATs and repeat as needed.  Alternately, Release() might
4631 //     detach and extract a successor, but then pass the residual list to the wakee.
4632 //     The wakee would be responsible for reattaching and remerging before it
4633 //     competed for the lock.
4634 //
4635 // Both "pop" and DMR are immune from ABA corruption -- there can be
4636 // multiple concurrent pushers, but only one popper or detacher.
4637 // This implementation pops from the head of the list.  This is unfair,
4638 // but tends to provide excellent throughput as hot threads remain hot.
4639 // (We wake recently run threads first).
4640 
4641 void Thread::muxRelease (volatile intptr_t * Lock)  {
4642   for (;;) {
4643     const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4644     assert (w & LOCKBIT, "invariant") ;
4645     if (w == LOCKBIT) return ;
4646     ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4647     assert (List != NULL, "invariant") ;
4648     assert (List->OnList == intptr_t(Lock), "invariant") ;
4649     ParkEvent * nxt = List->ListNext ;
4650 
4651     // The following CAS() releases the lock and pops the head element.
4652     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4653       continue ;
4654     }
4655     List->OnList = 0 ;
4656     OrderAccess::fence() ;
4657     List->unpark () ;
4658     return ;
4659   }
4660 }
4661 
4662 
4663 void Threads::verify() {
4664   ALL_JAVA_THREADS(p) {
4665     p->verify();
4666   }
4667   VMThread* thread = VMThread::vm_thread();
4668   if (thread != NULL) thread->verify();
4669 }