1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/javaClasses.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "code/scopeDesc.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "interpreter/interpreter.hpp"
  33 #include "interpreter/linkResolver.hpp"
  34 #include "interpreter/oopMapCache.hpp"
  35 #include "jvmtifiles/jvmtiEnv.hpp"
  36 #include "memory/gcLocker.inline.hpp"
  37 #include "memory/metaspaceShared.hpp"
  38 #include "memory/oopFactory.hpp"
  39 #include "memory/universe.inline.hpp"
  40 #include "oops/instanceKlass.hpp"
  41 #include "oops/objArrayOop.hpp"
  42 #include "oops/oop.inline.hpp"
  43 #include "oops/symbol.hpp"
  44 #include "prims/jvm_misc.hpp"
  45 #include "prims/jvmtiExport.hpp"
  46 #include "prims/jvmtiThreadState.hpp"
  47 #include "prims/privilegedStack.hpp"
  48 #include "runtime/arguments.hpp"
  49 #include "runtime/biasedLocking.hpp"
  50 #include "runtime/deoptimization.hpp"
  51 #include "runtime/fprofiler.hpp"
  52 #include "runtime/frame.inline.hpp"
  53 #include "runtime/init.hpp"
  54 #include "runtime/interfaceSupport.hpp"
  55 #include "runtime/java.hpp"
  56 #include "runtime/javaCalls.hpp"
  57 #include "runtime/jniPeriodicChecker.hpp"
  58 #include "runtime/memprofiler.hpp"
  59 #include "runtime/mutexLocker.hpp"
  60 #include "runtime/objectMonitor.hpp"
  61 #include "runtime/orderAccess.inline.hpp"
  62 #include "runtime/osThread.hpp"
  63 #include "runtime/safepoint.hpp"
  64 #include "runtime/sharedRuntime.hpp"
  65 #include "runtime/statSampler.hpp"
  66 #include "runtime/stubRoutines.hpp"
  67 #include "runtime/task.hpp"
  68 #include "runtime/thread.inline.hpp"
  69 #include "runtime/threadCritical.hpp"
  70 #include "runtime/threadLocalStorage.hpp"
  71 #include "runtime/vframe.hpp"
  72 #include "runtime/vframeArray.hpp"
  73 #include "runtime/vframe_hp.hpp"
  74 #include "runtime/vmThread.hpp"
  75 #include "runtime/vm_operations.hpp"
  76 #include "services/attachListener.hpp"
  77 #include "services/management.hpp"
  78 #include "services/memTracker.hpp"
  79 #include "services/threadService.hpp"
  80 #include "trace/tracing.hpp"
  81 #include "trace/traceMacros.hpp"
  82 #include "utilities/defaultStream.hpp"
  83 #include "utilities/dtrace.hpp"
  84 #include "utilities/events.hpp"
  85 #include "utilities/preserveException.hpp"
  86 #include "utilities/macros.hpp"
  87 #ifdef TARGET_OS_FAMILY_linux
  88 # include "os_linux.inline.hpp"
  89 #endif
  90 #ifdef TARGET_OS_FAMILY_solaris
  91 # include "os_solaris.inline.hpp"
  92 #endif
  93 #ifdef TARGET_OS_FAMILY_windows
  94 # include "os_windows.inline.hpp"
  95 #endif
  96 #ifdef TARGET_OS_FAMILY_bsd
  97 # include "os_bsd.inline.hpp"
  98 #endif
  99 #if INCLUDE_ALL_GCS
 100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
 101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
 103 #endif // INCLUDE_ALL_GCS
 104 #ifdef COMPILER1
 105 #include "c1/c1_Compiler.hpp"
 106 #endif
 107 #ifdef COMPILER2
 108 #include "opto/c2compiler.hpp"
 109 #include "opto/idealGraphPrinter.hpp"
 110 #endif
 111 #if INCLUDE_RTM_OPT
 112 #include "runtime/rtmLocking.hpp"
 113 #endif
 114 
 115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 116 
 117 #ifdef DTRACE_ENABLED
 118 
 119 // Only bother with this argument setup if dtrace is available
 120 
 121 #ifndef USDT2
 122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
 123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
 124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
 125   intptr_t, intptr_t, bool);
 126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
 127   intptr_t, intptr_t, bool);
 128 
 129 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 130   {                                                                        \
 131     ResourceMark rm(this);                                                 \
 132     int len = 0;                                                           \
 133     const char* name = (javathread)->get_thread_name();                    \
 134     len = strlen(name);                                                    \
 135     HS_DTRACE_PROBE5(hotspot, thread__##probe,                             \
 136       name, len,                                                           \
 137       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 138       (javathread)->osthread()->thread_id(),                               \
 139       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 140   }
 141 
 142 #else /* USDT2 */
 143 
 144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
 145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
 146 
 147 #define DTRACE_THREAD_PROBE(probe, javathread)                             \
 148   {                                                                        \
 149     ResourceMark rm(this);                                                 \
 150     int len = 0;                                                           \
 151     const char* name = (javathread)->get_thread_name();                    \
 152     len = strlen(name);                                                    \
 153     HOTSPOT_THREAD_PROBE_##probe(  /* probe = start, stop */               \
 154       (char *) name, len,                                                           \
 155       java_lang_Thread::thread_id((javathread)->threadObj()),              \
 156       (uintptr_t) (javathread)->osthread()->thread_id(),                               \
 157       java_lang_Thread::is_daemon((javathread)->threadObj()));             \
 158   }
 159 
 160 #endif /* USDT2 */
 161 
 162 #else //  ndef DTRACE_ENABLED
 163 
 164 #define DTRACE_THREAD_PROBE(probe, javathread)
 165 
 166 #endif // ndef DTRACE_ENABLED
 167 
 168 
 169 // Class hierarchy
 170 // - Thread
 171 //   - VMThread
 172 //   - WatcherThread
 173 //   - ConcurrentMarkSweepThread
 174 //   - JavaThread
 175 //     - CompilerThread
 176 
 177 // ======= Thread ========
 178 // Support for forcing alignment of thread objects for biased locking
 179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 180   if (UseBiasedLocking) {
 181     const int alignment = markOopDesc::biased_lock_alignment;
 182     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 183     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 184                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 185                                               AllocFailStrategy::RETURN_NULL);
 186     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
 187     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 188            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 189            "JavaThread alignment code overflowed allocated storage");
 190     if (TraceBiasedLocking) {
 191       if (aligned_addr != real_malloc_addr)
 192         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 193                       real_malloc_addr, aligned_addr);
 194     }
 195     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 196     return aligned_addr;
 197   } else {
 198     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 199                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 200   }
 201 }
 202 
 203 void Thread::operator delete(void* p) {
 204   if (UseBiasedLocking) {
 205     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
 206     FreeHeap(real_malloc_addr, mtThread);
 207   } else {
 208     FreeHeap(p, mtThread);
 209   }
 210 }
 211 
 212 
 213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 214 // JavaThread
 215 
 216 
 217 Thread::Thread() {
 218   // stack and get_thread
 219   set_stack_base(NULL);
 220   set_stack_size(0);
 221   set_self_raw_id(0);
 222   set_lgrp_id(-1);
 223 
 224   // allocated data structures
 225   set_osthread(NULL);
 226   set_resource_area(new (mtThread)ResourceArea());
 227   DEBUG_ONLY(_current_resource_mark = NULL;)
 228   set_handle_area(new (mtThread) HandleArea(NULL));
 229   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 230   set_active_handles(NULL);
 231   set_free_handle_block(NULL);
 232   set_last_handle_mark(NULL);
 233 
 234   // This initial value ==> never claimed.
 235   _oops_do_parity = 0;
 236 
 237   _metadata_on_stack_buffer = NULL;
 238 
 239   // the handle mark links itself to last_handle_mark
 240   new HandleMark(this);
 241 
 242   // plain initialization
 243   debug_only(_owned_locks = NULL;)
 244   debug_only(_allow_allocation_count = 0;)
 245   NOT_PRODUCT(_allow_safepoint_count = 0;)
 246   NOT_PRODUCT(_skip_gcalot = false;)
 247   _jvmti_env_iteration_count = 0;
 248   set_allocated_bytes(0);
 249   _vm_operation_started_count = 0;
 250   _vm_operation_completed_count = 0;
 251   _current_pending_monitor = NULL;
 252   _current_pending_monitor_is_from_java = true;
 253   _current_waiting_monitor = NULL;
 254   _num_nested_signal = 0;
 255   omFreeList = NULL ;
 256   omFreeCount = 0 ;
 257   omFreeProvision = 32 ;
 258   omInUseList = NULL ;
 259   omInUseCount = 0 ;
 260 
 261 #ifdef ASSERT
 262   _visited_for_critical_count = false;
 263 #endif
 264 
 265   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
 266   _suspend_flags = 0;
 267 
 268   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 269   _hashStateX = os::random() ;
 270   _hashStateY = 842502087 ;
 271   _hashStateZ = 0x8767 ;    // (int)(3579807591LL & 0xffff) ;
 272   _hashStateW = 273326509 ;
 273 
 274   _OnTrap   = 0 ;
 275   _schedctl = NULL ;
 276   _Stalled  = 0 ;
 277   _TypeTag  = 0x2BAD ;
 278 
 279   // Many of the following fields are effectively final - immutable
 280   // Note that nascent threads can't use the Native Monitor-Mutex
 281   // construct until the _MutexEvent is initialized ...
 282   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 283   // we might instead use a stack of ParkEvents that we could provision on-demand.
 284   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 285   // and ::Release()
 286   _ParkEvent   = ParkEvent::Allocate (this) ;
 287   _SleepEvent  = ParkEvent::Allocate (this) ;
 288   _MutexEvent  = ParkEvent::Allocate (this) ;
 289   _MuxEvent    = ParkEvent::Allocate (this) ;
 290 
 291 #ifdef CHECK_UNHANDLED_OOPS
 292   if (CheckUnhandledOops) {
 293     _unhandled_oops = new UnhandledOops(this);
 294   }
 295 #endif // CHECK_UNHANDLED_OOPS
 296 #ifdef ASSERT
 297   if (UseBiasedLocking) {
 298     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 299     assert(this == _real_malloc_address ||
 300            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 301            "bug in forced alignment of thread objects");
 302   }
 303 #endif /* ASSERT */
 304 }
 305 
 306 void Thread::initialize_thread_local_storage() {
 307   // Note: Make sure this method only calls
 308   // non-blocking operations. Otherwise, it might not work
 309   // with the thread-startup/safepoint interaction.
 310 
 311   // During Java thread startup, safepoint code should allow this
 312   // method to complete because it may need to allocate memory to
 313   // store information for the new thread.
 314 
 315   // initialize structure dependent on thread local storage
 316   ThreadLocalStorage::set_thread(this);
 317 }
 318 
 319 void Thread::record_stack_base_and_size() {
 320   set_stack_base(os::current_stack_base());
 321   set_stack_size(os::current_stack_size());
 322   if (is_Java_thread()) {
 323     ((JavaThread*) this)->set_stack_overflow_limit();
 324   }
 325   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 326   // in initialize_thread(). Without the adjustment, stack size is
 327   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 328   // So far, only Solaris has real implementation of initialize_thread().
 329   //
 330   // set up any platform-specific state.
 331   os::initialize_thread(this);
 332 
 333 #if INCLUDE_NMT
 334   // record thread's native stack, stack grows downward
 335   address stack_low_addr = stack_base() - stack_size();
 336   MemTracker::record_thread_stack(stack_low_addr, stack_size());
 337 #endif // INCLUDE_NMT
 338 }
 339 
 340 
 341 Thread::~Thread() {
 342   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 343   ObjectSynchronizer::omFlush (this) ;
 344 
 345   EVENT_THREAD_DESTRUCT(this);
 346 
 347   // stack_base can be NULL if the thread is never started or exited before
 348   // record_stack_base_and_size called. Although, we would like to ensure
 349   // that all started threads do call record_stack_base_and_size(), there is
 350   // not proper way to enforce that.
 351 #if INCLUDE_NMT
 352   if (_stack_base != NULL) {
 353     address low_stack_addr = stack_base() - stack_size();
 354     MemTracker::release_thread_stack(low_stack_addr, stack_size());
 355 #ifdef ASSERT
 356     set_stack_base(NULL);
 357 #endif
 358   }
 359 #endif // INCLUDE_NMT
 360 
 361   // deallocate data structures
 362   delete resource_area();
 363   // since the handle marks are using the handle area, we have to deallocated the root
 364   // handle mark before deallocating the thread's handle area,
 365   assert(last_handle_mark() != NULL, "check we have an element");
 366   delete last_handle_mark();
 367   assert(last_handle_mark() == NULL, "check we have reached the end");
 368 
 369   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 370   // We NULL out the fields for good hygiene.
 371   ParkEvent::Release (_ParkEvent)   ; _ParkEvent   = NULL ;
 372   ParkEvent::Release (_SleepEvent)  ; _SleepEvent  = NULL ;
 373   ParkEvent::Release (_MutexEvent)  ; _MutexEvent  = NULL ;
 374   ParkEvent::Release (_MuxEvent)    ; _MuxEvent    = NULL ;
 375 
 376   delete handle_area();
 377   delete metadata_handles();
 378 
 379   // osthread() can be NULL, if creation of thread failed.
 380   if (osthread() != NULL) os::free_thread(osthread());
 381 
 382   delete _SR_lock;
 383 
 384   // clear thread local storage if the Thread is deleting itself
 385   if (this == Thread::current()) {
 386     ThreadLocalStorage::set_thread(NULL);
 387   } else {
 388     // In the case where we're not the current thread, invalidate all the
 389     // caches in case some code tries to get the current thread or the
 390     // thread that was destroyed, and gets stale information.
 391     ThreadLocalStorage::invalidate_all();
 392   }
 393   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 394 }
 395 
 396 // NOTE: dummy function for assertion purpose.
 397 void Thread::run() {
 398   ShouldNotReachHere();
 399 }
 400 
 401 #ifdef ASSERT
 402 // Private method to check for dangling thread pointer
 403 void check_for_dangling_thread_pointer(Thread *thread) {
 404  assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 405          "possibility of dangling Thread pointer");
 406 }
 407 #endif
 408 
 409 
 410 #ifndef PRODUCT
 411 // Tracing method for basic thread operations
 412 void Thread::trace(const char* msg, const Thread* const thread) {
 413   if (!TraceThreadEvents) return;
 414   ResourceMark rm;
 415   ThreadCritical tc;
 416   const char *name = "non-Java thread";
 417   int prio = -1;
 418   if (thread->is_Java_thread()
 419       && !thread->is_Compiler_thread()) {
 420     // The Threads_lock must be held to get information about
 421     // this thread but may not be in some situations when
 422     // tracing  thread events.
 423     bool release_Threads_lock = false;
 424     if (!Threads_lock->owned_by_self()) {
 425       Threads_lock->lock();
 426       release_Threads_lock = true;
 427     }
 428     JavaThread* jt = (JavaThread *)thread;
 429     name = (char *)jt->get_thread_name();
 430     oop thread_oop = jt->threadObj();
 431     if (thread_oop != NULL) {
 432       prio = java_lang_Thread::priority(thread_oop);
 433     }
 434     if (release_Threads_lock) {
 435       Threads_lock->unlock();
 436     }
 437   }
 438   tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
 439 }
 440 #endif
 441 
 442 
 443 ThreadPriority Thread::get_priority(const Thread* const thread) {
 444   trace("get priority", thread);
 445   ThreadPriority priority;
 446   // Can return an error!
 447   (void)os::get_priority(thread, priority);
 448   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 449   return priority;
 450 }
 451 
 452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 453   trace("set priority", thread);
 454   debug_only(check_for_dangling_thread_pointer(thread);)
 455   // Can return an error!
 456   (void)os::set_priority(thread, priority);
 457 }
 458 
 459 
 460 void Thread::start(Thread* thread) {
 461   trace("start", thread);
 462   // Start is different from resume in that its safety is guaranteed by context or
 463   // being called from a Java method synchronized on the Thread object.
 464   if (!DisableStartThread) {
 465     if (thread->is_Java_thread()) {
 466       // Initialize the thread state to RUNNABLE before starting this thread.
 467       // Can not set it after the thread started because we do not know the
 468       // exact thread state at that time. It could be in MONITOR_WAIT or
 469       // in SLEEPING or some other state.
 470       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 471                                           java_lang_Thread::RUNNABLE);
 472     }
 473     os::start_thread(thread);
 474   }
 475 }
 476 
 477 // Enqueue a VM_Operation to do the job for us - sometime later
 478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 479   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 480   VMThread::execute(vm_stop);
 481 }
 482 
 483 
 484 //
 485 // Check if an external suspend request has completed (or has been
 486 // cancelled). Returns true if the thread is externally suspended and
 487 // false otherwise.
 488 //
 489 // The bits parameter returns information about the code path through
 490 // the routine. Useful for debugging:
 491 //
 492 // set in is_ext_suspend_completed():
 493 // 0x00000001 - routine was entered
 494 // 0x00000010 - routine return false at end
 495 // 0x00000100 - thread exited (return false)
 496 // 0x00000200 - suspend request cancelled (return false)
 497 // 0x00000400 - thread suspended (return true)
 498 // 0x00001000 - thread is in a suspend equivalent state (return true)
 499 // 0x00002000 - thread is native and walkable (return true)
 500 // 0x00004000 - thread is native_trans and walkable (needed retry)
 501 //
 502 // set in wait_for_ext_suspend_completion():
 503 // 0x00010000 - routine was entered
 504 // 0x00020000 - suspend request cancelled before loop (return false)
 505 // 0x00040000 - thread suspended before loop (return true)
 506 // 0x00080000 - suspend request cancelled in loop (return false)
 507 // 0x00100000 - thread suspended in loop (return true)
 508 // 0x00200000 - suspend not completed during retry loop (return false)
 509 //
 510 
 511 // Helper class for tracing suspend wait debug bits.
 512 //
 513 // 0x00000100 indicates that the target thread exited before it could
 514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 515 // 0x00080000 each indicate a cancelled suspend request so they don't
 516 // count as wait failures either.
 517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 518 
 519 class TraceSuspendDebugBits : public StackObj {
 520  private:
 521   JavaThread * jt;
 522   bool         is_wait;
 523   bool         called_by_wait;  // meaningful when !is_wait
 524   uint32_t *   bits;
 525 
 526  public:
 527   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 528                         uint32_t *_bits) {
 529     jt             = _jt;
 530     is_wait        = _is_wait;
 531     called_by_wait = _called_by_wait;
 532     bits           = _bits;
 533   }
 534 
 535   ~TraceSuspendDebugBits() {
 536     if (!is_wait) {
 537 #if 1
 538       // By default, don't trace bits for is_ext_suspend_completed() calls.
 539       // That trace is very chatty.
 540       return;
 541 #else
 542       if (!called_by_wait) {
 543         // If tracing for is_ext_suspend_completed() is enabled, then only
 544         // trace calls to it from wait_for_ext_suspend_completion()
 545         return;
 546       }
 547 #endif
 548     }
 549 
 550     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 551       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 552         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 553         ResourceMark rm;
 554 
 555         tty->print_cr(
 556             "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 557             jt->get_thread_name(), *bits);
 558 
 559         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 560       }
 561     }
 562   }
 563 };
 564 #undef DEBUG_FALSE_BITS
 565 
 566 
 567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
 568   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 569 
 570   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 571   bool do_trans_retry;           // flag to force the retry
 572 
 573   *bits |= 0x00000001;
 574 
 575   do {
 576     do_trans_retry = false;
 577 
 578     if (is_exiting()) {
 579       // Thread is in the process of exiting. This is always checked
 580       // first to reduce the risk of dereferencing a freed JavaThread.
 581       *bits |= 0x00000100;
 582       return false;
 583     }
 584 
 585     if (!is_external_suspend()) {
 586       // Suspend request is cancelled. This is always checked before
 587       // is_ext_suspended() to reduce the risk of a rogue resume
 588       // confusing the thread that made the suspend request.
 589       *bits |= 0x00000200;
 590       return false;
 591     }
 592 
 593     if (is_ext_suspended()) {
 594       // thread is suspended
 595       *bits |= 0x00000400;
 596       return true;
 597     }
 598 
 599     // Now that we no longer do hard suspends of threads running
 600     // native code, the target thread can be changing thread state
 601     // while we are in this routine:
 602     //
 603     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 604     //
 605     // We save a copy of the thread state as observed at this moment
 606     // and make our decision about suspend completeness based on the
 607     // copy. This closes the race where the thread state is seen as
 608     // _thread_in_native_trans in the if-thread_blocked check, but is
 609     // seen as _thread_blocked in if-thread_in_native_trans check.
 610     JavaThreadState save_state = thread_state();
 611 
 612     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 613       // If the thread's state is _thread_blocked and this blocking
 614       // condition is known to be equivalent to a suspend, then we can
 615       // consider the thread to be externally suspended. This means that
 616       // the code that sets _thread_blocked has been modified to do
 617       // self-suspension if the blocking condition releases. We also
 618       // used to check for CONDVAR_WAIT here, but that is now covered by
 619       // the _thread_blocked with self-suspension check.
 620       //
 621       // Return true since we wouldn't be here unless there was still an
 622       // external suspend request.
 623       *bits |= 0x00001000;
 624       return true;
 625     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 626       // Threads running native code will self-suspend on native==>VM/Java
 627       // transitions. If its stack is walkable (should always be the case
 628       // unless this function is called before the actual java_suspend()
 629       // call), then the wait is done.
 630       *bits |= 0x00002000;
 631       return true;
 632     } else if (!called_by_wait && !did_trans_retry &&
 633                save_state == _thread_in_native_trans &&
 634                frame_anchor()->walkable()) {
 635       // The thread is transitioning from thread_in_native to another
 636       // thread state. check_safepoint_and_suspend_for_native_trans()
 637       // will force the thread to self-suspend. If it hasn't gotten
 638       // there yet we may have caught the thread in-between the native
 639       // code check above and the self-suspend. Lucky us. If we were
 640       // called by wait_for_ext_suspend_completion(), then it
 641       // will be doing the retries so we don't have to.
 642       //
 643       // Since we use the saved thread state in the if-statement above,
 644       // there is a chance that the thread has already transitioned to
 645       // _thread_blocked by the time we get here. In that case, we will
 646       // make a single unnecessary pass through the logic below. This
 647       // doesn't hurt anything since we still do the trans retry.
 648 
 649       *bits |= 0x00004000;
 650 
 651       // Once the thread leaves thread_in_native_trans for another
 652       // thread state, we break out of this retry loop. We shouldn't
 653       // need this flag to prevent us from getting back here, but
 654       // sometimes paranoia is good.
 655       did_trans_retry = true;
 656 
 657       // We wait for the thread to transition to a more usable state.
 658       for (int i = 1; i <= SuspendRetryCount; i++) {
 659         // We used to do an "os::yield_all(i)" call here with the intention
 660         // that yielding would increase on each retry. However, the parameter
 661         // is ignored on Linux which means the yield didn't scale up. Waiting
 662         // on the SR_lock below provides a much more predictable scale up for
 663         // the delay. It also provides a simple/direct point to check for any
 664         // safepoint requests from the VMThread
 665 
 666         // temporarily drops SR_lock while doing wait with safepoint check
 667         // (if we're a JavaThread - the WatcherThread can also call this)
 668         // and increase delay with each retry
 669         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 670 
 671         // check the actual thread state instead of what we saved above
 672         if (thread_state() != _thread_in_native_trans) {
 673           // the thread has transitioned to another thread state so
 674           // try all the checks (except this one) one more time.
 675           do_trans_retry = true;
 676           break;
 677         }
 678       } // end retry loop
 679 
 680 
 681     }
 682   } while (do_trans_retry);
 683 
 684   *bits |= 0x00000010;
 685   return false;
 686 }
 687 
 688 //
 689 // Wait for an external suspend request to complete (or be cancelled).
 690 // Returns true if the thread is externally suspended and false otherwise.
 691 //
 692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 693        uint32_t *bits) {
 694   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 695                              false /* !called_by_wait */, bits);
 696 
 697   // local flag copies to minimize SR_lock hold time
 698   bool is_suspended;
 699   bool pending;
 700   uint32_t reset_bits;
 701 
 702   // set a marker so is_ext_suspend_completed() knows we are the caller
 703   *bits |= 0x00010000;
 704 
 705   // We use reset_bits to reinitialize the bits value at the top of
 706   // each retry loop. This allows the caller to make use of any
 707   // unused bits for their own marking purposes.
 708   reset_bits = *bits;
 709 
 710   {
 711     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 712     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 713                                             delay, bits);
 714     pending = is_external_suspend();
 715   }
 716   // must release SR_lock to allow suspension to complete
 717 
 718   if (!pending) {
 719     // A cancelled suspend request is the only false return from
 720     // is_ext_suspend_completed() that keeps us from entering the
 721     // retry loop.
 722     *bits |= 0x00020000;
 723     return false;
 724   }
 725 
 726   if (is_suspended) {
 727     *bits |= 0x00040000;
 728     return true;
 729   }
 730 
 731   for (int i = 1; i <= retries; i++) {
 732     *bits = reset_bits;  // reinit to only track last retry
 733 
 734     // We used to do an "os::yield_all(i)" call here with the intention
 735     // that yielding would increase on each retry. However, the parameter
 736     // is ignored on Linux which means the yield didn't scale up. Waiting
 737     // on the SR_lock below provides a much more predictable scale up for
 738     // the delay. It also provides a simple/direct point to check for any
 739     // safepoint requests from the VMThread
 740 
 741     {
 742       MutexLocker ml(SR_lock());
 743       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 744       // can also call this)  and increase delay with each retry
 745       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 746 
 747       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 748                                               delay, bits);
 749 
 750       // It is possible for the external suspend request to be cancelled
 751       // (by a resume) before the actual suspend operation is completed.
 752       // Refresh our local copy to see if we still need to wait.
 753       pending = is_external_suspend();
 754     }
 755 
 756     if (!pending) {
 757       // A cancelled suspend request is the only false return from
 758       // is_ext_suspend_completed() that keeps us from staying in the
 759       // retry loop.
 760       *bits |= 0x00080000;
 761       return false;
 762     }
 763 
 764     if (is_suspended) {
 765       *bits |= 0x00100000;
 766       return true;
 767     }
 768   } // end retry loop
 769 
 770   // thread did not suspend after all our retries
 771   *bits |= 0x00200000;
 772   return false;
 773 }
 774 
 775 #ifndef PRODUCT
 776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
 777 
 778   // This should not need to be atomic as the only way for simultaneous
 779   // updates is via interrupts. Even then this should be rare or non-existant
 780   // and we don't care that much anyway.
 781 
 782   int index = _jmp_ring_index;
 783   _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
 784   _jmp_ring[index]._target = (intptr_t) target;
 785   _jmp_ring[index]._instruction = (intptr_t) instr;
 786   _jmp_ring[index]._file = file;
 787   _jmp_ring[index]._line = line;
 788 }
 789 #endif /* PRODUCT */
 790 
 791 // Called by flat profiler
 792 // Callers have already called wait_for_ext_suspend_completion
 793 // The assertion for that is currently too complex to put here:
 794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 795   bool gotframe = false;
 796   // self suspension saves needed state.
 797   if (has_last_Java_frame() && _anchor.walkable()) {
 798      *_fr = pd_last_frame();
 799      gotframe = true;
 800   }
 801   return gotframe;
 802 }
 803 
 804 void Thread::interrupt(Thread* thread) {
 805   trace("interrupt", thread);
 806   debug_only(check_for_dangling_thread_pointer(thread);)
 807   os::interrupt(thread);
 808 }
 809 
 810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 811   trace("is_interrupted", thread);
 812   debug_only(check_for_dangling_thread_pointer(thread);)
 813   // Note:  If clear_interrupted==false, this simply fetches and
 814   // returns the value of the field osthread()->interrupted().
 815   return os::is_interrupted(thread, clear_interrupted);
 816 }
 817 
 818 
 819 // GC Support
 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 821   jint thread_parity = _oops_do_parity;
 822   if (thread_parity != strong_roots_parity) {
 823     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 824     if (res == thread_parity) {
 825       return true;
 826     } else {
 827       guarantee(res == strong_roots_parity, "Or else what?");
 828       assert(SharedHeap::heap()->workers()->active_workers() > 0,
 829          "Should only fail when parallel.");
 830       return false;
 831     }
 832   }
 833   assert(SharedHeap::heap()->workers()->active_workers() > 0,
 834          "Should only fail when parallel.");
 835   return false;
 836 }
 837 
 838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
 839   active_handles()->oops_do(f);
 840   // Do oop for ThreadShadow
 841   f->do_oop((oop*)&_pending_exception);
 842   handle_area()->oops_do(f);
 843 }
 844 
 845 void Thread::nmethods_do(CodeBlobClosure* cf) {
 846   // no nmethods in a generic thread...
 847 }
 848 
 849 void Thread::metadata_do(void f(Metadata*)) {
 850   if (metadata_handles() != NULL) {
 851     for (int i = 0; i< metadata_handles()->length(); i++) {
 852       f(metadata_handles()->at(i));
 853     }
 854   }
 855 }
 856 
 857 void Thread::print_on(outputStream* st) const {
 858   // get_priority assumes osthread initialized
 859   if (osthread() != NULL) {
 860     int os_prio;
 861     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 862       st->print("os_prio=%d ", os_prio);
 863     }
 864     st->print("tid=" INTPTR_FORMAT " ", this);
 865     ext().print_on(st);
 866     osthread()->print_on(st);
 867   }
 868   debug_only(if (WizardMode) print_owned_locks_on(st);)
 869 }
 870 
 871 // Thread::print_on_error() is called by fatal error handler. Don't use
 872 // any lock or allocate memory.
 873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 874   if      (is_VM_thread())                  st->print("VMThread");
 875   else if (is_Compiler_thread())            st->print("CompilerThread");
 876   else if (is_Java_thread())                st->print("JavaThread");
 877   else if (is_GC_task_thread())             st->print("GCTaskThread");
 878   else if (is_Watcher_thread())             st->print("WatcherThread");
 879   else if (is_ConcurrentGC_thread())        st->print("ConcurrentGCThread");
 880   else st->print("Thread");
 881 
 882   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 883             _stack_base - _stack_size, _stack_base);
 884 
 885   if (osthread()) {
 886     st->print(" [id=%d]", osthread()->thread_id());
 887   }
 888 }
 889 
 890 #ifdef ASSERT
 891 void Thread::print_owned_locks_on(outputStream* st) const {
 892   Monitor *cur = _owned_locks;
 893   if (cur == NULL) {
 894     st->print(" (no locks) ");
 895   } else {
 896     st->print_cr(" Locks owned:");
 897     while(cur) {
 898       cur->print_on(st);
 899       cur = cur->next();
 900     }
 901   }
 902 }
 903 
 904 static int ref_use_count  = 0;
 905 
 906 bool Thread::owns_locks_but_compiled_lock() const {
 907   for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 908     if (cur != Compile_lock) return true;
 909   }
 910   return false;
 911 }
 912 
 913 
 914 #endif
 915 
 916 #ifndef PRODUCT
 917 
 918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 920 // no threads which allow_vm_block's are held
 921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 922     // Check if current thread is allowed to block at a safepoint
 923     if (!(_allow_safepoint_count == 0))
 924       fatal("Possible safepoint reached by thread that does not allow it");
 925     if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 926       fatal("LEAF method calling lock?");
 927     }
 928 
 929 #ifdef ASSERT
 930     if (potential_vm_operation && is_Java_thread()
 931         && !Universe::is_bootstrapping()) {
 932       // Make sure we do not hold any locks that the VM thread also uses.
 933       // This could potentially lead to deadlocks
 934       for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 935         // Threads_lock is special, since the safepoint synchronization will not start before this is
 936         // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 937         // since it is used to transfer control between JavaThreads and the VMThread
 938         // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
 939         if ( (cur->allow_vm_block() &&
 940               cur != Threads_lock &&
 941               cur != Compile_lock &&               // Temporary: should not be necessary when we get spearate compilation
 942               cur != VMOperationRequest_lock &&
 943               cur != VMOperationQueue_lock) ||
 944               cur->rank() == Mutex::special) {
 945           fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
 946         }
 947       }
 948     }
 949 
 950     if (GCALotAtAllSafepoints) {
 951       // We could enter a safepoint here and thus have a gc
 952       InterfaceSupport::check_gc_alot();
 953     }
 954 #endif
 955 }
 956 #endif
 957 
 958 bool Thread::is_in_stack(address adr) const {
 959   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 960   address end = os::current_stack_pointer();
 961   // Allow non Java threads to call this without stack_base
 962   if (_stack_base == NULL) return true;
 963   if (stack_base() >= adr && adr >= end) return true;
 964 
 965   return false;
 966 }
 967 
 968 
 969 bool Thread::is_in_usable_stack(address adr) const {
 970   size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
 971   size_t usable_stack_size = _stack_size - stack_guard_size;
 972 
 973   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
 974 }
 975 
 976 
 977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 979 // used for compilation in the future. If that change is made, the need for these methods
 980 // should be revisited, and they should be removed if possible.
 981 
 982 bool Thread::is_lock_owned(address adr) const {
 983   return on_local_stack(adr);
 984 }
 985 
 986 bool Thread::set_as_starting_thread() {
 987  // NOTE: this must be called inside the main thread.
 988   return os::create_main_thread((JavaThread*)this);
 989 }
 990 
 991 static void initialize_class(Symbol* class_name, TRAPS) {
 992   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 993   InstanceKlass::cast(klass)->initialize(CHECK);
 994 }
 995 
 996 
 997 // Creates the initial ThreadGroup
 998 static Handle create_initial_thread_group(TRAPS) {
 999   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1000   instanceKlassHandle klass (THREAD, k);
1001 
1002   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1003   {
1004     JavaValue result(T_VOID);
1005     JavaCalls::call_special(&result,
1006                             system_instance,
1007                             klass,
1008                             vmSymbols::object_initializer_name(),
1009                             vmSymbols::void_method_signature(),
1010                             CHECK_NH);
1011   }
1012   Universe::set_system_thread_group(system_instance());
1013 
1014   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1015   {
1016     JavaValue result(T_VOID);
1017     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1018     JavaCalls::call_special(&result,
1019                             main_instance,
1020                             klass,
1021                             vmSymbols::object_initializer_name(),
1022                             vmSymbols::threadgroup_string_void_signature(),
1023                             system_instance,
1024                             string,
1025                             CHECK_NH);
1026   }
1027   return main_instance;
1028 }
1029 
1030 // Creates the initial Thread
1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1032   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1033   instanceKlassHandle klass (THREAD, k);
1034   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1035 
1036   java_lang_Thread::set_thread(thread_oop(), thread);
1037   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1038   thread->set_threadObj(thread_oop());
1039 
1040   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1041 
1042   JavaValue result(T_VOID);
1043   JavaCalls::call_special(&result, thread_oop,
1044                                    klass,
1045                                    vmSymbols::object_initializer_name(),
1046                                    vmSymbols::threadgroup_string_void_signature(),
1047                                    thread_group,
1048                                    string,
1049                                    CHECK_NULL);
1050   return thread_oop();
1051 }
1052 
1053 static void call_initializeSystemClass(TRAPS) {
1054   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1055   instanceKlassHandle klass (THREAD, k);
1056 
1057   JavaValue result(T_VOID);
1058   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1059                                          vmSymbols::void_method_signature(), CHECK);
1060 }
1061 
1062 char java_runtime_name[128] = "";
1063 char java_runtime_version[128] = "";
1064 
1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1066 static const char* get_java_runtime_name(TRAPS) {
1067   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069   fieldDescriptor fd;
1070   bool found = k != NULL &&
1071                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1072                                                         vmSymbols::string_signature(), &fd);
1073   if (found) {
1074     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075     if (name_oop == NULL)
1076       return NULL;
1077     const char* name = java_lang_String::as_utf8_string(name_oop,
1078                                                         java_runtime_name,
1079                                                         sizeof(java_runtime_name));
1080     return name;
1081   } else {
1082     return NULL;
1083   }
1084 }
1085 
1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1087 static const char* get_java_runtime_version(TRAPS) {
1088   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1089                                       Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1090   fieldDescriptor fd;
1091   bool found = k != NULL &&
1092                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1093                                                         vmSymbols::string_signature(), &fd);
1094   if (found) {
1095     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1096     if (name_oop == NULL)
1097       return NULL;
1098     const char* name = java_lang_String::as_utf8_string(name_oop,
1099                                                         java_runtime_version,
1100                                                         sizeof(java_runtime_version));
1101     return name;
1102   } else {
1103     return NULL;
1104   }
1105 }
1106 
1107 // General purpose hook into Java code, run once when the VM is initialized.
1108 // The Java library method itself may be changed independently from the VM.
1109 static void call_postVMInitHook(TRAPS) {
1110   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1111   instanceKlassHandle klass (THREAD, k);
1112   if (klass.not_null()) {
1113     JavaValue result(T_VOID);
1114     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1115                                            vmSymbols::void_method_signature(),
1116                                            CHECK);
1117   }
1118 }
1119 
1120 static void reset_vm_info_property(TRAPS) {
1121   // the vm info string
1122   ResourceMark rm(THREAD);
1123   const char *vm_info = VM_Version::vm_info_string();
1124 
1125   // java.lang.System class
1126   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1127   instanceKlassHandle klass (THREAD, k);
1128 
1129   // setProperty arguments
1130   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1131   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1132 
1133   // return value
1134   JavaValue r(T_OBJECT);
1135 
1136   // public static String setProperty(String key, String value);
1137   JavaCalls::call_static(&r,
1138                          klass,
1139                          vmSymbols::setProperty_name(),
1140                          vmSymbols::string_string_string_signature(),
1141                          key_str,
1142                          value_str,
1143                          CHECK);
1144 }
1145 
1146 
1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1148   assert(thread_group.not_null(), "thread group should be specified");
1149   assert(threadObj() == NULL, "should only create Java thread object once");
1150 
1151   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1152   instanceKlassHandle klass (THREAD, k);
1153   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1154 
1155   java_lang_Thread::set_thread(thread_oop(), this);
1156   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1157   set_threadObj(thread_oop());
1158 
1159   JavaValue result(T_VOID);
1160   if (thread_name != NULL) {
1161     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1162     // Thread gets assigned specified name and null target
1163     JavaCalls::call_special(&result,
1164                             thread_oop,
1165                             klass,
1166                             vmSymbols::object_initializer_name(),
1167                             vmSymbols::threadgroup_string_void_signature(),
1168                             thread_group, // Argument 1
1169                             name,         // Argument 2
1170                             THREAD);
1171   } else {
1172     // Thread gets assigned name "Thread-nnn" and null target
1173     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1174     JavaCalls::call_special(&result,
1175                             thread_oop,
1176                             klass,
1177                             vmSymbols::object_initializer_name(),
1178                             vmSymbols::threadgroup_runnable_void_signature(),
1179                             thread_group, // Argument 1
1180                             Handle(),     // Argument 2
1181                             THREAD);
1182   }
1183 
1184 
1185   if (daemon) {
1186       java_lang_Thread::set_daemon(thread_oop());
1187   }
1188 
1189   if (HAS_PENDING_EXCEPTION) {
1190     return;
1191   }
1192 
1193   KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1194   Handle threadObj(this, this->threadObj());
1195 
1196   JavaCalls::call_special(&result,
1197                          thread_group,
1198                          group,
1199                          vmSymbols::add_method_name(),
1200                          vmSymbols::thread_void_signature(),
1201                          threadObj,          // Arg 1
1202                          THREAD);
1203 
1204 
1205 }
1206 
1207 // NamedThread --  non-JavaThread subclasses with multiple
1208 // uniquely named instances should derive from this.
1209 NamedThread::NamedThread() : Thread() {
1210   _name = NULL;
1211   _processed_thread = NULL;
1212 }
1213 
1214 NamedThread::~NamedThread() {
1215   if (_name != NULL) {
1216     FREE_C_HEAP_ARRAY(char, _name, mtThread);
1217     _name = NULL;
1218   }
1219 }
1220 
1221 void NamedThread::set_name(const char* format, ...) {
1222   guarantee(_name == NULL, "Only get to set name once.");
1223   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1224   guarantee(_name != NULL, "alloc failure");
1225   va_list ap;
1226   va_start(ap, format);
1227   jio_vsnprintf(_name, max_name_len, format, ap);
1228   va_end(ap);
1229 }
1230 
1231 // ======= WatcherThread ========
1232 
1233 // The watcher thread exists to simulate timer interrupts.  It should
1234 // be replaced by an abstraction over whatever native support for
1235 // timer interrupts exists on the platform.
1236 
1237 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1238 bool WatcherThread::_startable = false;
1239 volatile bool  WatcherThread::_should_terminate = false;
1240 
1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1242   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1243   if (os::create_thread(this, os::watcher_thread)) {
1244     _watcher_thread = this;
1245 
1246     // Set the watcher thread to the highest OS priority which should not be
1247     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1248     // is created. The only normal thread using this priority is the reference
1249     // handler thread, which runs for very short intervals only.
1250     // If the VMThread's priority is not lower than the WatcherThread profiling
1251     // will be inaccurate.
1252     os::set_priority(this, MaxPriority);
1253     if (!DisableStartThread) {
1254       os::start_thread(this);
1255     }
1256   }
1257 }
1258 
1259 int WatcherThread::sleep() const {
1260   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1261 
1262   // remaining will be zero if there are no tasks,
1263   // causing the WatcherThread to sleep until a task is
1264   // enrolled
1265   int remaining = PeriodicTask::time_to_wait();
1266   int time_slept = 0;
1267 
1268   // we expect this to timeout - we only ever get unparked when
1269   // we should terminate or when a new task has been enrolled
1270   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1271 
1272   jlong time_before_loop = os::javaTimeNanos();
1273 
1274   for (;;) {
1275     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1276     jlong now = os::javaTimeNanos();
1277 
1278     if (remaining == 0) {
1279         // if we didn't have any tasks we could have waited for a long time
1280         // consider the time_slept zero and reset time_before_loop
1281         time_slept = 0;
1282         time_before_loop = now;
1283     } else {
1284         // need to recalulate since we might have new tasks in _tasks
1285         time_slept = (int) ((now - time_before_loop) / 1000000);
1286     }
1287 
1288     // Change to task list or spurious wakeup of some kind
1289     if (timedout || _should_terminate) {
1290         break;
1291     }
1292 
1293     remaining = PeriodicTask::time_to_wait();
1294     if (remaining == 0) {
1295         // Last task was just disenrolled so loop around and wait until
1296         // another task gets enrolled
1297         continue;
1298     }
1299 
1300     remaining -= time_slept;
1301     if (remaining <= 0)
1302       break;
1303   }
1304 
1305   return time_slept;
1306 }
1307 
1308 void WatcherThread::run() {
1309   assert(this == watcher_thread(), "just checking");
1310 
1311   this->record_stack_base_and_size();
1312   this->initialize_thread_local_storage();
1313   this->set_active_handles(JNIHandleBlock::allocate_block());
1314   while(!_should_terminate) {
1315     assert(watcher_thread() == Thread::current(),  "thread consistency check");
1316     assert(watcher_thread() == this,  "thread consistency check");
1317 
1318     // Calculate how long it'll be until the next PeriodicTask work
1319     // should be done, and sleep that amount of time.
1320     int time_waited = sleep();
1321 
1322     if (is_error_reported()) {
1323       // A fatal error has happened, the error handler(VMError::report_and_die)
1324       // should abort JVM after creating an error log file. However in some
1325       // rare cases, the error handler itself might deadlock. Here we try to
1326       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1327       //
1328       // This code is in WatcherThread because WatcherThread wakes up
1329       // periodically so the fatal error handler doesn't need to do anything;
1330       // also because the WatcherThread is less likely to crash than other
1331       // threads.
1332 
1333       for (;;) {
1334         if (!ShowMessageBoxOnError
1335          && (OnError == NULL || OnError[0] == '\0')
1336          && Arguments::abort_hook() == NULL) {
1337              os::sleep(this, 2 * 60 * 1000, false);
1338              fdStream err(defaultStream::output_fd());
1339              err.print_raw_cr("# [ timer expired, abort... ]");
1340              // skip atexit/vm_exit/vm_abort hooks
1341              os::die();
1342         }
1343 
1344         // Wake up 5 seconds later, the fatal handler may reset OnError or
1345         // ShowMessageBoxOnError when it is ready to abort.
1346         os::sleep(this, 5 * 1000, false);
1347       }
1348     }
1349 
1350     PeriodicTask::real_time_tick(time_waited);
1351   }
1352 
1353   // Signal that it is terminated
1354   {
1355     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1356     _watcher_thread = NULL;
1357     Terminator_lock->notify();
1358   }
1359 
1360   // Thread destructor usually does this..
1361   ThreadLocalStorage::set_thread(NULL);
1362 }
1363 
1364 void WatcherThread::start() {
1365   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366 
1367   if (watcher_thread() == NULL && _startable) {
1368     _should_terminate = false;
1369     // Create the single instance of WatcherThread
1370     new WatcherThread();
1371   }
1372 }
1373 
1374 void WatcherThread::make_startable() {
1375   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376   _startable = true;
1377 }
1378 
1379 void WatcherThread::stop() {
1380   {
1381     MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1382     _should_terminate = true;
1383     OrderAccess::fence();  // ensure WatcherThread sees update in main loop
1384 
1385     WatcherThread* watcher = watcher_thread();
1386     if (watcher != NULL)
1387       watcher->unpark();
1388   }
1389 
1390   // it is ok to take late safepoints here, if needed
1391   MutexLocker mu(Terminator_lock);
1392 
1393   while(watcher_thread() != NULL) {
1394     // This wait should make safepoint checks, wait without a timeout,
1395     // and wait as a suspend-equivalent condition.
1396     //
1397     // Note: If the FlatProfiler is running, then this thread is waiting
1398     // for the WatcherThread to terminate and the WatcherThread, via the
1399     // FlatProfiler task, is waiting for the external suspend request on
1400     // this thread to complete. wait_for_ext_suspend_completion() will
1401     // eventually timeout, but that takes time. Making this wait a
1402     // suspend-equivalent condition solves that timeout problem.
1403     //
1404     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1405                           Mutex::_as_suspend_equivalent_flag);
1406   }
1407 }
1408 
1409 void WatcherThread::unpark() {
1410   MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1411   PeriodicTask_lock->notify();
1412 }
1413 
1414 void WatcherThread::print_on(outputStream* st) const {
1415   st->print("\"%s\" ", name());
1416   Thread::print_on(st);
1417   st->cr();
1418 }
1419 
1420 // ======= JavaThread ========
1421 
1422 // A JavaThread is a normal Java thread
1423 
1424 void JavaThread::initialize() {
1425   // Initialize fields
1426 
1427   // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1428   set_claimed_par_id(UINT_MAX);
1429 
1430   set_saved_exception_pc(NULL);
1431   set_threadObj(NULL);
1432   _anchor.clear();
1433   set_entry_point(NULL);
1434   set_jni_functions(jni_functions());
1435   set_callee_target(NULL);
1436   set_vm_result(NULL);
1437   set_vm_result_2(NULL);
1438   set_vframe_array_head(NULL);
1439   set_vframe_array_last(NULL);
1440   set_deferred_locals(NULL);
1441   set_deopt_mark(NULL);
1442   set_deopt_nmethod(NULL);
1443   clear_must_deopt_id();
1444   set_monitor_chunks(NULL);
1445   set_next(NULL);
1446   set_thread_state(_thread_new);
1447   _terminated = _not_terminated;
1448   _privileged_stack_top = NULL;
1449   _array_for_gc = NULL;
1450   _suspend_equivalent = false;
1451   _in_deopt_handler = 0;
1452   _doing_unsafe_access = false;
1453   _stack_guard_state = stack_guard_unused;
1454   (void)const_cast<oop&>(_exception_oop = NULL);
1455   _exception_pc  = 0;
1456   _exception_handler_pc = 0;
1457   _is_method_handle_return = 0;
1458   _jvmti_thread_state= NULL;
1459   _should_post_on_exceptions_flag = JNI_FALSE;
1460   _jvmti_get_loaded_classes_closure = NULL;
1461   _interp_only_mode    = 0;
1462   _special_runtime_exit_condition = _no_async_condition;
1463   _pending_async_exception = NULL;
1464   _thread_stat = NULL;
1465   _thread_stat = new ThreadStatistics();
1466   _blocked_on_compilation = false;
1467   _jni_active_critical = 0;
1468   _do_not_unlock_if_synchronized = false;
1469   _cached_monitor_info = NULL;
1470   _parker = Parker::Allocate(this) ;
1471 
1472 #ifndef PRODUCT
1473   _jmp_ring_index = 0;
1474   for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1475     record_jump(NULL, NULL, NULL, 0);
1476   }
1477 #endif /* PRODUCT */
1478 
1479   set_thread_profiler(NULL);
1480   if (FlatProfiler::is_active()) {
1481     // This is where we would decide to either give each thread it's own profiler
1482     // or use one global one from FlatProfiler,
1483     // or up to some count of the number of profiled threads, etc.
1484     ThreadProfiler* pp = new ThreadProfiler();
1485     pp->engage();
1486     set_thread_profiler(pp);
1487   }
1488 
1489   // Setup safepoint state info for this thread
1490   ThreadSafepointState::create(this);
1491 
1492   debug_only(_java_call_counter = 0);
1493 
1494   // JVMTI PopFrame support
1495   _popframe_condition = popframe_inactive;
1496   _popframe_preserved_args = NULL;
1497   _popframe_preserved_args_size = 0;
1498   _frames_to_pop_failed_realloc = 0;
1499 
1500   pd_initialize();
1501 }
1502 
1503 #if INCLUDE_ALL_GCS
1504 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1505 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1506 #endif // INCLUDE_ALL_GCS
1507 
1508 JavaThread::JavaThread(bool is_attaching_via_jni) :
1509   Thread()
1510 #if INCLUDE_ALL_GCS
1511   , _satb_mark_queue(&_satb_mark_queue_set),
1512   _dirty_card_queue(&_dirty_card_queue_set)
1513 #endif // INCLUDE_ALL_GCS
1514 {
1515   initialize();
1516   if (is_attaching_via_jni) {
1517     _jni_attach_state = _attaching_via_jni;
1518   } else {
1519     _jni_attach_state = _not_attaching_via_jni;
1520   }
1521   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1522 }
1523 
1524 bool JavaThread::reguard_stack(address cur_sp) {
1525   if (_stack_guard_state != stack_guard_yellow_disabled) {
1526     return true; // Stack already guarded or guard pages not needed.
1527   }
1528 
1529   if (register_stack_overflow()) {
1530     // For those architectures which have separate register and
1531     // memory stacks, we must check the register stack to see if
1532     // it has overflowed.
1533     return false;
1534   }
1535 
1536   // Java code never executes within the yellow zone: the latter is only
1537   // there to provoke an exception during stack banging.  If java code
1538   // is executing there, either StackShadowPages should be larger, or
1539   // some exception code in c1, c2 or the interpreter isn't unwinding
1540   // when it should.
1541   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1542 
1543   enable_stack_yellow_zone();
1544   return true;
1545 }
1546 
1547 bool JavaThread::reguard_stack(void) {
1548   return reguard_stack(os::current_stack_pointer());
1549 }
1550 
1551 
1552 void JavaThread::block_if_vm_exited() {
1553   if (_terminated == _vm_exited) {
1554     // _vm_exited is set at safepoint, and Threads_lock is never released
1555     // we will block here forever
1556     Threads_lock->lock_without_safepoint_check();
1557     ShouldNotReachHere();
1558   }
1559 }
1560 
1561 
1562 // Remove this ifdef when C1 is ported to the compiler interface.
1563 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1564 
1565 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1566   Thread()
1567 #if INCLUDE_ALL_GCS
1568   , _satb_mark_queue(&_satb_mark_queue_set),
1569   _dirty_card_queue(&_dirty_card_queue_set)
1570 #endif // INCLUDE_ALL_GCS
1571 {
1572   if (TraceThreadEvents) {
1573     tty->print_cr("creating thread %p", this);
1574   }
1575   initialize();
1576   _jni_attach_state = _not_attaching_via_jni;
1577   set_entry_point(entry_point);
1578   // Create the native thread itself.
1579   // %note runtime_23
1580   os::ThreadType thr_type = os::java_thread;
1581   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1582                                                      os::java_thread;
1583   os::create_thread(this, thr_type, stack_sz);
1584   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1585   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1586   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1587   // the exception consists of creating the exception object & initializing it, initialization
1588   // will leave the VM via a JavaCall and then all locks must be unlocked).
1589   //
1590   // The thread is still suspended when we reach here. Thread must be explicit started
1591   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1592   // by calling Threads:add. The reason why this is not done here, is because the thread
1593   // object must be fully initialized (take a look at JVM_Start)
1594 }
1595 
1596 JavaThread::~JavaThread() {
1597   if (TraceThreadEvents) {
1598       tty->print_cr("terminate thread %p", this);
1599   }
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     if (!is_Compiler_thread()) {
1817       int count = 3;
1818       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1819         EXCEPTION_MARK;
1820         JavaValue result(T_VOID);
1821         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1822         JavaCalls::call_virtual(&result,
1823                               threadObj, thread_klass,
1824                               vmSymbols::exit_method_name(),
1825                               vmSymbols::void_method_signature(),
1826                               THREAD);
1827         CLEAR_PENDING_EXCEPTION;
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, CLDClosure* 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   prepare_ext();
3029 
3030   // Add the new thread to the Threads list and set it in motion.
3031   // We must have threads lock in order to call Threads::add.
3032   // It is crucial that we do not block before the thread is
3033   // added to the Threads list for if a GC happens, then the java_thread oop
3034   // will not be visited by GC.
3035   Threads::add(this);
3036 }
3037 
3038 oop JavaThread::current_park_blocker() {
3039   // Support for JSR-166 locks
3040   oop thread_oop = threadObj();
3041   if (thread_oop != NULL &&
3042       JDK_Version::current().supports_thread_park_blocker()) {
3043     return java_lang_Thread::park_blocker(thread_oop);
3044   }
3045   return NULL;
3046 }
3047 
3048 
3049 void JavaThread::print_stack_on(outputStream* st) {
3050   if (!has_last_Java_frame()) return;
3051   ResourceMark rm;
3052   HandleMark   hm;
3053 
3054   RegisterMap reg_map(this);
3055   vframe* start_vf = last_java_vframe(&reg_map);
3056   int count = 0;
3057   for (vframe* f = start_vf; f; f = f->sender() ) {
3058     if (f->is_java_frame()) {
3059       javaVFrame* jvf = javaVFrame::cast(f);
3060       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3061 
3062       // Print out lock information
3063       if (JavaMonitorsInStackTrace) {
3064         jvf->print_lock_info_on(st, count);
3065       }
3066     } else {
3067       // Ignore non-Java frames
3068     }
3069 
3070     // Bail-out case for too deep stacks
3071     count++;
3072     if (MaxJavaStackTraceDepth == count) return;
3073   }
3074 }
3075 
3076 
3077 // JVMTI PopFrame support
3078 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3079   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3080   if (in_bytes(size_in_bytes) != 0) {
3081     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3082     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3083     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3084   }
3085 }
3086 
3087 void* JavaThread::popframe_preserved_args() {
3088   return _popframe_preserved_args;
3089 }
3090 
3091 ByteSize JavaThread::popframe_preserved_args_size() {
3092   return in_ByteSize(_popframe_preserved_args_size);
3093 }
3094 
3095 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3096   int sz = in_bytes(popframe_preserved_args_size());
3097   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3098   return in_WordSize(sz / wordSize);
3099 }
3100 
3101 void JavaThread::popframe_free_preserved_args() {
3102   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3103   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3104   _popframe_preserved_args = NULL;
3105   _popframe_preserved_args_size = 0;
3106 }
3107 
3108 #ifndef PRODUCT
3109 
3110 void JavaThread::trace_frames() {
3111   tty->print_cr("[Describe stack]");
3112   int frame_no = 1;
3113   for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3114     tty->print("  %d. ", frame_no++);
3115     fst.current()->print_value_on(tty,this);
3116     tty->cr();
3117   }
3118 }
3119 
3120 class PrintAndVerifyOopClosure: public OopClosure {
3121  protected:
3122   template <class T> inline void do_oop_work(T* p) {
3123     oop obj = oopDesc::load_decode_heap_oop(p);
3124     if (obj == NULL) return;
3125     tty->print(INTPTR_FORMAT ": ", p);
3126     if (obj->is_oop_or_null()) {
3127       if (obj->is_objArray()) {
3128         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3129       } else {
3130         obj->print();
3131       }
3132     } else {
3133       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3134     }
3135     tty->cr();
3136   }
3137  public:
3138   virtual void do_oop(oop* p) { do_oop_work(p); }
3139   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3140 };
3141 
3142 
3143 static void oops_print(frame* f, const RegisterMap *map) {
3144   PrintAndVerifyOopClosure print;
3145   f->print_value();
3146   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3147 }
3148 
3149 // Print our all the locations that contain oops and whether they are
3150 // valid or not.  This useful when trying to find the oldest frame
3151 // where an oop has gone bad since the frame walk is from youngest to
3152 // oldest.
3153 void JavaThread::trace_oops() {
3154   tty->print_cr("[Trace oops]");
3155   frames_do(oops_print);
3156 }
3157 
3158 
3159 #ifdef ASSERT
3160 // Print or validate the layout of stack frames
3161 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3162   ResourceMark rm;
3163   PRESERVE_EXCEPTION_MARK;
3164   FrameValues values;
3165   int frame_no = 0;
3166   for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3167     fst.current()->describe(values, ++frame_no);
3168     if (depth == frame_no) break;
3169   }
3170   if (validate_only) {
3171     values.validate();
3172   } else {
3173     tty->print_cr("[Describe stack layout]");
3174     values.print(this);
3175   }
3176 }
3177 #endif
3178 
3179 void JavaThread::trace_stack_from(vframe* start_vf) {
3180   ResourceMark rm;
3181   int vframe_no = 1;
3182   for (vframe* f = start_vf; f; f = f->sender() ) {
3183     if (f->is_java_frame()) {
3184       javaVFrame::cast(f)->print_activation(vframe_no++);
3185     } else {
3186       f->print();
3187     }
3188     if (vframe_no > StackPrintLimit) {
3189       tty->print_cr("...<more frames>...");
3190       return;
3191     }
3192   }
3193 }
3194 
3195 
3196 void JavaThread::trace_stack() {
3197   if (!has_last_Java_frame()) return;
3198   ResourceMark rm;
3199   HandleMark   hm;
3200   RegisterMap reg_map(this);
3201   trace_stack_from(last_java_vframe(&reg_map));
3202 }
3203 
3204 
3205 #endif // PRODUCT
3206 
3207 
3208 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3209   assert(reg_map != NULL, "a map must be given");
3210   frame f = last_frame();
3211   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3212     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3213   }
3214   return NULL;
3215 }
3216 
3217 
3218 Klass* JavaThread::security_get_caller_class(int depth) {
3219   vframeStream vfst(this);
3220   vfst.security_get_caller_frame(depth);
3221   if (!vfst.at_end()) {
3222     return vfst.method()->method_holder();
3223   }
3224   return NULL;
3225 }
3226 
3227 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3228   assert(thread->is_Compiler_thread(), "must be compiler thread");
3229   CompileBroker::compiler_thread_loop();
3230 }
3231 
3232 // Create a CompilerThread
3233 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3234 : JavaThread(&compiler_thread_entry) {
3235   _env   = NULL;
3236   _log   = NULL;
3237   _task  = NULL;
3238   _queue = queue;
3239   _counters = counters;
3240   _buffer_blob = NULL;
3241   _scanned_nmethod = NULL;
3242   _compiler = NULL;
3243 
3244 #ifndef PRODUCT
3245   _ideal_graph_printer = NULL;
3246 #endif
3247 }
3248 
3249 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3250   JavaThread::oops_do(f, cld_f, cf);
3251   if (_scanned_nmethod != NULL && cf != NULL) {
3252     // Safepoints can occur when the sweeper is scanning an nmethod so
3253     // process it here to make sure it isn't unloaded in the middle of
3254     // a scan.
3255     cf->do_code_blob(_scanned_nmethod);
3256   }
3257 }
3258 
3259 
3260 // ======= Threads ========
3261 
3262 // The Threads class links together all active threads, and provides
3263 // operations over all threads.  It is protected by its own Mutex
3264 // lock, which is also used in other contexts to protect thread
3265 // operations from having the thread being operated on from exiting
3266 // and going away unexpectedly (e.g., safepoint synchronization)
3267 
3268 JavaThread* Threads::_thread_list = NULL;
3269 int         Threads::_number_of_threads = 0;
3270 int         Threads::_number_of_non_daemon_threads = 0;
3271 int         Threads::_return_code = 0;
3272 size_t      JavaThread::_stack_size_at_create = 0;
3273 #ifdef ASSERT
3274 bool        Threads::_vm_complete = false;
3275 #endif
3276 
3277 // All JavaThreads
3278 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3279 
3280 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3281 void Threads::threads_do(ThreadClosure* tc) {
3282   assert_locked_or_safepoint(Threads_lock);
3283   // ALL_JAVA_THREADS iterates through all JavaThreads
3284   ALL_JAVA_THREADS(p) {
3285     tc->do_thread(p);
3286   }
3287   // Someday we could have a table or list of all non-JavaThreads.
3288   // For now, just manually iterate through them.
3289   tc->do_thread(VMThread::vm_thread());
3290   Universe::heap()->gc_threads_do(tc);
3291   WatcherThread *wt = WatcherThread::watcher_thread();
3292   // Strictly speaking, the following NULL check isn't sufficient to make sure
3293   // the data for WatcherThread is still valid upon being examined. However,
3294   // considering that WatchThread terminates when the VM is on the way to
3295   // exit at safepoint, the chance of the above is extremely small. The right
3296   // way to prevent termination of WatcherThread would be to acquire
3297   // Terminator_lock, but we can't do that without violating the lock rank
3298   // checking in some cases.
3299   if (wt != NULL)
3300     tc->do_thread(wt);
3301 
3302   // If CompilerThreads ever become non-JavaThreads, add them here
3303 }
3304 
3305 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3306 
3307   extern void JDK_Version_init();
3308 
3309   // Check version
3310   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3311 
3312   // Initialize the output stream module
3313   ostream_init();
3314 
3315   // Process java launcher properties.
3316   Arguments::process_sun_java_launcher_properties(args);
3317 
3318   // Initialize the os module before using TLS
3319   os::init();
3320 
3321   // Initialize system properties.
3322   Arguments::init_system_properties();
3323 
3324   // So that JDK version can be used as a discrimintor when parsing arguments
3325   JDK_Version_init();
3326 
3327   // Update/Initialize System properties after JDK version number is known
3328   Arguments::init_version_specific_system_properties();
3329 
3330   // Parse arguments
3331   jint parse_result = Arguments::parse(args);
3332   if (parse_result != JNI_OK) return parse_result;
3333 
3334   os::init_before_ergo();
3335 
3336   jint ergo_result = Arguments::apply_ergo();
3337   if (ergo_result != JNI_OK) return ergo_result;
3338 
3339   if (PauseAtStartup) {
3340     os::pause();
3341   }
3342 
3343 #ifndef USDT2
3344   HS_DTRACE_PROBE(hotspot, vm__init__begin);
3345 #else /* USDT2 */
3346   HOTSPOT_VM_INIT_BEGIN();
3347 #endif /* USDT2 */
3348 
3349   // Record VM creation timing statistics
3350   TraceVmCreationTime create_vm_timer;
3351   create_vm_timer.start();
3352 
3353   // Timing (must come after argument parsing)
3354   TraceTime timer("Create VM", TraceStartupTime);
3355 
3356   // Initialize the os module after parsing the args
3357   jint os_init_2_result = os::init_2();
3358   if (os_init_2_result != JNI_OK) return os_init_2_result;
3359 
3360   jint adjust_after_os_result = Arguments::adjust_after_os();
3361   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3362 
3363   // intialize TLS
3364   ThreadLocalStorage::init();
3365 
3366   // Initialize output stream logging
3367   ostream_init_log();
3368 
3369   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3370   // Must be before create_vm_init_agents()
3371   if (Arguments::init_libraries_at_startup()) {
3372     convert_vm_init_libraries_to_agents();
3373   }
3374 
3375   // Launch -agentlib/-agentpath and converted -Xrun agents
3376   if (Arguments::init_agents_at_startup()) {
3377     create_vm_init_agents();
3378   }
3379 
3380   // Initialize Threads state
3381   _thread_list = NULL;
3382   _number_of_threads = 0;
3383   _number_of_non_daemon_threads = 0;
3384 
3385   // Initialize global data structures and create system classes in heap
3386   vm_init_globals();
3387 
3388   // Attach the main thread to this os thread
3389   JavaThread* main_thread = new JavaThread();
3390   main_thread->set_thread_state(_thread_in_vm);
3391   // must do this before set_active_handles and initialize_thread_local_storage
3392   // Note: on solaris initialize_thread_local_storage() will (indirectly)
3393   // change the stack size recorded here to one based on the java thread
3394   // stacksize. This adjusted size is what is used to figure the placement
3395   // of the guard pages.
3396   main_thread->record_stack_base_and_size();
3397   main_thread->initialize_thread_local_storage();
3398 
3399   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3400 
3401   if (!main_thread->set_as_starting_thread()) {
3402     vm_shutdown_during_initialization(
3403       "Failed necessary internal allocation. Out of swap space");
3404     delete main_thread;
3405     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3406     return JNI_ENOMEM;
3407   }
3408 
3409   // Enable guard page *after* os::create_main_thread(), otherwise it would
3410   // crash Linux VM, see notes in os_linux.cpp.
3411   main_thread->create_stack_guard_pages();
3412 
3413   // Initialize Java-Level synchronization subsystem
3414   ObjectMonitor::Initialize() ;
3415 
3416   // Initialize global modules
3417   jint status = init_globals();
3418   if (status != JNI_OK) {
3419     delete main_thread;
3420     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3421     return status;
3422   }
3423 
3424   // Should be done after the heap is fully created
3425   main_thread->cache_global_variables();
3426 
3427   HandleMark hm;
3428 
3429   { MutexLocker mu(Threads_lock);
3430     Threads::add(main_thread);
3431   }
3432 
3433   // Any JVMTI raw monitors entered in onload will transition into
3434   // real raw monitor. VM is setup enough here for raw monitor enter.
3435   JvmtiExport::transition_pending_onload_raw_monitors();
3436 
3437   // Create the VMThread
3438   { TraceTime timer("Start VMThread", TraceStartupTime);
3439     VMThread::create();
3440     Thread* vmthread = VMThread::vm_thread();
3441 
3442     if (!os::create_thread(vmthread, os::vm_thread))
3443       vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3444 
3445     // Wait for the VM thread to become ready, and VMThread::run to initialize
3446     // Monitors can have spurious returns, must always check another state flag
3447     {
3448       MutexLocker ml(Notify_lock);
3449       os::start_thread(vmthread);
3450       while (vmthread->active_handles() == NULL) {
3451         Notify_lock->wait();
3452       }
3453     }
3454   }
3455 
3456   assert (Universe::is_fully_initialized(), "not initialized");
3457   if (VerifyDuringStartup) {
3458     // Make sure we're starting with a clean slate.
3459     VM_Verify verify_op;
3460     VMThread::execute(&verify_op);
3461   }
3462 
3463   EXCEPTION_MARK;
3464 
3465   // At this point, the Universe is initialized, but we have not executed
3466   // any byte code.  Now is a good time (the only time) to dump out the
3467   // internal state of the JVM for sharing.
3468   if (DumpSharedSpaces) {
3469     MetaspaceShared::preload_and_dump(CHECK_0);
3470     ShouldNotReachHere();
3471   }
3472 
3473   // Always call even when there are not JVMTI environments yet, since environments
3474   // may be attached late and JVMTI must track phases of VM execution
3475   JvmtiExport::enter_start_phase();
3476 
3477   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3478   JvmtiExport::post_vm_start();
3479 
3480   {
3481     TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3482 
3483     if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3484       create_vm_init_libraries();
3485     }
3486 
3487     initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3488 
3489     // Initialize java_lang.System (needed before creating the thread)
3490     initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3491     initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3492     Handle thread_group = create_initial_thread_group(CHECK_0);
3493     Universe::set_main_thread_group(thread_group());
3494     initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3495     oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3496     main_thread->set_threadObj(thread_object);
3497     // Set thread status to running since main thread has
3498     // been started and running.
3499     java_lang_Thread::set_thread_status(thread_object,
3500                                         java_lang_Thread::RUNNABLE);
3501 
3502     // The VM creates & returns objects of this class. Make sure it's initialized.
3503     initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3504 
3505     // The VM preresolves methods to these classes. Make sure that they get initialized
3506     initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3507     initialize_class(vmSymbols::java_lang_ref_Finalizer(),  CHECK_0);
3508     call_initializeSystemClass(CHECK_0);
3509 
3510     // get the Java runtime name after java.lang.System is initialized
3511     JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3512     JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3513 
3514     // an instance of OutOfMemory exception has been allocated earlier
3515     initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3516     initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3517     initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3518     initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3519     initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3520     initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3521     initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3522     initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3523   }
3524 
3525   // See        : bugid 4211085.
3526   // Background : the static initializer of java.lang.Compiler tries to read
3527   //              property"java.compiler" and read & write property "java.vm.info".
3528   //              When a security manager is installed through the command line
3529   //              option "-Djava.security.manager", the above properties are not
3530   //              readable and the static initializer for java.lang.Compiler fails
3531   //              resulting in a NoClassDefFoundError.  This can happen in any
3532   //              user code which calls methods in java.lang.Compiler.
3533   // Hack :       the hack is to pre-load and initialize this class, so that only
3534   //              system domains are on the stack when the properties are read.
3535   //              Currently even the AWT code has calls to methods in java.lang.Compiler.
3536   //              On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3537   // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3538   //              read and write"java.vm.info" in the default policy file. See bugid 4211383
3539   //              Once that is done, we should remove this hack.
3540   initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3541 
3542   // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3543   // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3544   // compiler does not get loaded through java.lang.Compiler).  "java -version" with the
3545   // hotspot vm says "nojit" all the time which is confusing.  So, we reset it here.
3546   // This should also be taken out as soon as 4211383 gets fixed.
3547   reset_vm_info_property(CHECK_0);
3548 
3549   quicken_jni_functions();
3550 
3551   // Must be run after init_ft which initializes ft_enabled
3552   if (TRACE_INITIALIZE() != JNI_OK) {
3553     vm_exit_during_initialization("Failed to initialize tracing backend");
3554   }
3555 
3556   // Set flag that basic initialization has completed. Used by exceptions and various
3557   // debug stuff, that does not work until all basic classes have been initialized.
3558   set_init_completed();
3559 
3560   Metaspace::post_initialize();
3561 
3562 #ifndef USDT2
3563   HS_DTRACE_PROBE(hotspot, vm__init__end);
3564 #else /* USDT2 */
3565   HOTSPOT_VM_INIT_END();
3566 #endif /* USDT2 */
3567 
3568   // record VM initialization completion time
3569 #if INCLUDE_MANAGEMENT
3570   Management::record_vm_init_completed();
3571 #endif // INCLUDE_MANAGEMENT
3572 
3573   // Compute system loader. Note that this has to occur after set_init_completed, since
3574   // valid exceptions may be thrown in the process.
3575   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3576   // set_init_completed has just been called, causing exceptions not to be shortcut
3577   // anymore. We call vm_exit_during_initialization directly instead.
3578   SystemDictionary::compute_java_system_loader(THREAD);
3579   if (HAS_PENDING_EXCEPTION) {
3580     vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3581   }
3582 
3583 #if INCLUDE_ALL_GCS
3584   // Support for ConcurrentMarkSweep. This should be cleaned up
3585   // and better encapsulated. The ugly nested if test would go away
3586   // once things are properly refactored. XXX YSR
3587   if (UseConcMarkSweepGC || UseG1GC) {
3588     if (UseConcMarkSweepGC) {
3589       ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3590     } else {
3591       ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3592     }
3593     if (HAS_PENDING_EXCEPTION) {
3594       vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3595     }
3596   }
3597 #endif // INCLUDE_ALL_GCS
3598 
3599   // Always call even when there are not JVMTI environments yet, since environments
3600   // may be attached late and JVMTI must track phases of VM execution
3601   JvmtiExport::enter_live_phase();
3602 
3603   // Signal Dispatcher needs to be started before VMInit event is posted
3604   os::signal_init();
3605 
3606   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3607   if (!DisableAttachMechanism) {
3608     AttachListener::vm_start();
3609     if (StartAttachListener || AttachListener::init_at_startup()) {
3610       AttachListener::init();
3611     }
3612   }
3613 
3614   // Launch -Xrun agents
3615   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3616   // back-end can launch with -Xdebug -Xrunjdwp.
3617   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3618     create_vm_init_libraries();
3619   }
3620 
3621   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3622   JvmtiExport::post_vm_initialized();
3623 
3624   if (TRACE_START() != JNI_OK) {
3625     vm_exit_during_initialization("Failed to start tracing backend.");
3626   }
3627 
3628   if (CleanChunkPoolAsync) {
3629     Chunk::start_chunk_pool_cleaner_task();
3630   }
3631 
3632   // initialize compiler(s)
3633 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3634   CompileBroker::compilation_init();
3635 #endif
3636 
3637   if (EnableInvokeDynamic) {
3638     // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3639     // It is done after compilers are initialized, because otherwise compilations of
3640     // signature polymorphic MH intrinsics can be missed
3641     // (see SystemDictionary::find_method_handle_intrinsic).
3642     initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3643     initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3644     initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3645   }
3646 
3647 #if INCLUDE_MANAGEMENT
3648   Management::initialize(THREAD);
3649 #endif // INCLUDE_MANAGEMENT
3650 
3651   if (HAS_PENDING_EXCEPTION) {
3652     // management agent fails to start possibly due to
3653     // configuration problem and is responsible for printing
3654     // stack trace if appropriate. Simply exit VM.
3655     vm_exit(1);
3656   }
3657 
3658   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3659   if (MemProfiling)                   MemProfiler::engage();
3660   StatSampler::engage();
3661   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3662 
3663   BiasedLocking::init();
3664 
3665 #if INCLUDE_RTM_OPT
3666   RTMLockingCounters::init();
3667 #endif
3668 
3669   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3670     call_postVMInitHook(THREAD);
3671     // The Java side of PostVMInitHook.run must deal with all
3672     // exceptions and provide means of diagnosis.
3673     if (HAS_PENDING_EXCEPTION) {
3674       CLEAR_PENDING_EXCEPTION;
3675     }
3676   }
3677 
3678   {
3679       MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3680       // Make sure the watcher thread can be started by WatcherThread::start()
3681       // or by dynamic enrollment.
3682       WatcherThread::make_startable();
3683       // Start up the WatcherThread if there are any periodic tasks
3684       // NOTE:  All PeriodicTasks should be registered by now. If they
3685       //   aren't, late joiners might appear to start slowly (we might
3686       //   take a while to process their first tick).
3687       if (PeriodicTask::num_tasks() > 0) {
3688           WatcherThread::start();
3689       }
3690   }
3691 
3692   // Give os specific code one last chance to start
3693   os::init_3();
3694 
3695   create_vm_timer.end();
3696 #ifdef ASSERT
3697   _vm_complete = true;
3698 #endif
3699   return JNI_OK;
3700 }
3701 
3702 // type for the Agent_OnLoad and JVM_OnLoad entry points
3703 extern "C" {
3704   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3705 }
3706 // Find a command line agent library and return its entry point for
3707 //         -agentlib:  -agentpath:   -Xrun
3708 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3709 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3710   OnLoadEntry_t on_load_entry = NULL;
3711   void *library = NULL;
3712 
3713   if (!agent->valid()) {
3714     char buffer[JVM_MAXPATHLEN];
3715     char ebuf[1024];
3716     const char *name = agent->name();
3717     const char *msg = "Could not find agent library ";
3718 
3719     // First check to see if agent is statically linked into executable
3720     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3721       library = agent->os_lib();
3722     } else if (agent->is_absolute_path()) {
3723       library = os::dll_load(name, ebuf, sizeof ebuf);
3724       if (library == NULL) {
3725         const char *sub_msg = " in absolute path, with error: ";
3726         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3727         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3728         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3729         // If we can't find the agent, exit.
3730         vm_exit_during_initialization(buf, NULL);
3731         FREE_C_HEAP_ARRAY(char, buf, mtThread);
3732       }
3733     } else {
3734       // Try to load the agent from the standard dll directory
3735       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3736                              name)) {
3737         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3738       }
3739       if (library == NULL) { // Try the local directory
3740         char ns[1] = {0};
3741         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3742           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3743         }
3744         if (library == NULL) {
3745           const char *sub_msg = " on the library path, with error: ";
3746           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3747           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3748           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3749           // If we can't find the agent, exit.
3750           vm_exit_during_initialization(buf, NULL);
3751           FREE_C_HEAP_ARRAY(char, buf, mtThread);
3752         }
3753       }
3754     }
3755     agent->set_os_lib(library);
3756     agent->set_valid();
3757   }
3758 
3759   // Find the OnLoad function.
3760   on_load_entry =
3761     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3762                                                           false,
3763                                                           on_load_symbols,
3764                                                           num_symbol_entries));
3765   return on_load_entry;
3766 }
3767 
3768 // Find the JVM_OnLoad entry point
3769 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3770   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3771   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3772 }
3773 
3774 // Find the Agent_OnLoad entry point
3775 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3776   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3777   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3778 }
3779 
3780 // For backwards compatibility with -Xrun
3781 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3782 // treated like -agentpath:
3783 // Must be called before agent libraries are created
3784 void Threads::convert_vm_init_libraries_to_agents() {
3785   AgentLibrary* agent;
3786   AgentLibrary* next;
3787 
3788   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3789     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3790     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3791 
3792     // If there is an JVM_OnLoad function it will get called later,
3793     // otherwise see if there is an Agent_OnLoad
3794     if (on_load_entry == NULL) {
3795       on_load_entry = lookup_agent_on_load(agent);
3796       if (on_load_entry != NULL) {
3797         // switch it to the agent list -- so that Agent_OnLoad will be called,
3798         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3799         Arguments::convert_library_to_agent(agent);
3800       } else {
3801         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3802       }
3803     }
3804   }
3805 }
3806 
3807 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3808 // Invokes Agent_OnLoad
3809 // Called very early -- before JavaThreads exist
3810 void Threads::create_vm_init_agents() {
3811   extern struct JavaVM_ main_vm;
3812   AgentLibrary* agent;
3813 
3814   JvmtiExport::enter_onload_phase();
3815 
3816   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3817     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3818 
3819     if (on_load_entry != NULL) {
3820       // Invoke the Agent_OnLoad function
3821       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3822       if (err != JNI_OK) {
3823         vm_exit_during_initialization("agent library failed to init", agent->name());
3824       }
3825     } else {
3826       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3827     }
3828   }
3829   JvmtiExport::enter_primordial_phase();
3830 }
3831 
3832 extern "C" {
3833   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3834 }
3835 
3836 void Threads::shutdown_vm_agents() {
3837   // Send any Agent_OnUnload notifications
3838   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3839   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3840   extern struct JavaVM_ main_vm;
3841   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3842 
3843     // Find the Agent_OnUnload function.
3844     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3845       os::find_agent_function(agent,
3846       false,
3847       on_unload_symbols,
3848       num_symbol_entries));
3849 
3850     // Invoke the Agent_OnUnload function
3851     if (unload_entry != NULL) {
3852       JavaThread* thread = JavaThread::current();
3853       ThreadToNativeFromVM ttn(thread);
3854       HandleMark hm(thread);
3855       (*unload_entry)(&main_vm);
3856     }
3857   }
3858 }
3859 
3860 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3861 // Invokes JVM_OnLoad
3862 void Threads::create_vm_init_libraries() {
3863   extern struct JavaVM_ main_vm;
3864   AgentLibrary* agent;
3865 
3866   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3867     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3868 
3869     if (on_load_entry != NULL) {
3870       // Invoke the JVM_OnLoad function
3871       JavaThread* thread = JavaThread::current();
3872       ThreadToNativeFromVM ttn(thread);
3873       HandleMark hm(thread);
3874       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3875       if (err != JNI_OK) {
3876         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3877       }
3878     } else {
3879       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3880     }
3881   }
3882 }
3883 
3884 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3885   assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3886 
3887   JavaThread* java_thread = NULL;
3888   // Sequential search for now.  Need to do better optimization later.
3889   for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3890     oop tobj = thread->threadObj();
3891     if (!thread->is_exiting() &&
3892         tobj != NULL &&
3893         java_tid == java_lang_Thread::thread_id(tobj)) {
3894       java_thread = thread;
3895       break;
3896     }
3897   }
3898   return java_thread;
3899 }
3900 
3901 
3902 // Last thread running calls java.lang.Shutdown.shutdown()
3903 void JavaThread::invoke_shutdown_hooks() {
3904   HandleMark hm(this);
3905 
3906   // We could get here with a pending exception, if so clear it now.
3907   if (this->has_pending_exception()) {
3908     this->clear_pending_exception();
3909   }
3910 
3911   EXCEPTION_MARK;
3912   Klass* k =
3913     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3914                                       THREAD);
3915   if (k != NULL) {
3916     // SystemDictionary::resolve_or_null will return null if there was
3917     // an exception.  If we cannot load the Shutdown class, just don't
3918     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3919     // and finalizers (if runFinalizersOnExit is set) won't be run.
3920     // Note that if a shutdown hook was registered or runFinalizersOnExit
3921     // was called, the Shutdown class would have already been loaded
3922     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3923     instanceKlassHandle shutdown_klass (THREAD, k);
3924     JavaValue result(T_VOID);
3925     JavaCalls::call_static(&result,
3926                            shutdown_klass,
3927                            vmSymbols::shutdown_method_name(),
3928                            vmSymbols::void_method_signature(),
3929                            THREAD);
3930   }
3931   CLEAR_PENDING_EXCEPTION;
3932 }
3933 
3934 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3935 // the program falls off the end of main(). Another VM exit path is through
3936 // vm_exit() when the program calls System.exit() to return a value or when
3937 // there is a serious error in VM. The two shutdown paths are not exactly
3938 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3939 // and VM_Exit op at VM level.
3940 //
3941 // Shutdown sequence:
3942 //   + Shutdown native memory tracking if it is on
3943 //   + Wait until we are the last non-daemon thread to execute
3944 //     <-- every thing is still working at this moment -->
3945 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3946 //        shutdown hooks, run finalizers if finalization-on-exit
3947 //   + Call before_exit(), prepare for VM exit
3948 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3949 //        currently the only user of this mechanism is File.deleteOnExit())
3950 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3951 //        post thread end and vm death events to JVMTI,
3952 //        stop signal thread
3953 //   + Call JavaThread::exit(), it will:
3954 //      > release JNI handle blocks, remove stack guard pages
3955 //      > remove this thread from Threads list
3956 //     <-- no more Java code from this thread after this point -->
3957 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3958 //     the compiler threads at safepoint
3959 //     <-- do not use anything that could get blocked by Safepoint -->
3960 //   + Disable tracing at JNI/JVM barriers
3961 //   + Set _vm_exited flag for threads that are still running native code
3962 //   + Delete this thread
3963 //   + Call exit_globals()
3964 //      > deletes tty
3965 //      > deletes PerfMemory resources
3966 //   + Return to caller
3967 
3968 bool Threads::destroy_vm() {
3969   JavaThread* thread = JavaThread::current();
3970 
3971 #ifdef ASSERT
3972   _vm_complete = false;
3973 #endif
3974   // Wait until we are the last non-daemon thread to execute
3975   { MutexLocker nu(Threads_lock);
3976     while (Threads::number_of_non_daemon_threads() > 1 )
3977       // This wait should make safepoint checks, wait without a timeout,
3978       // and wait as a suspend-equivalent condition.
3979       //
3980       // Note: If the FlatProfiler is running and this thread is waiting
3981       // for another non-daemon thread to finish, then the FlatProfiler
3982       // is waiting for the external suspend request on this thread to
3983       // complete. wait_for_ext_suspend_completion() will eventually
3984       // timeout, but that takes time. Making this wait a suspend-
3985       // equivalent condition solves that timeout problem.
3986       //
3987       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3988                          Mutex::_as_suspend_equivalent_flag);
3989   }
3990 
3991   // Hang forever on exit if we are reporting an error.
3992   if (ShowMessageBoxOnError && is_error_reported()) {
3993     os::infinite_sleep();
3994   }
3995   os::wait_for_keypress_at_exit();
3996 
3997   if (JDK_Version::is_jdk12x_version()) {
3998     // We are the last thread running, so check if finalizers should be run.
3999     // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4000     HandleMark rm(thread);
4001     Universe::run_finalizers_on_exit();
4002   } else {
4003     // run Java level shutdown hooks
4004     thread->invoke_shutdown_hooks();
4005   }
4006 
4007   before_exit(thread);
4008 
4009   thread->exit(true);
4010 
4011   // Stop VM thread.
4012   {
4013     // 4945125 The vm thread comes to a safepoint during exit.
4014     // GC vm_operations can get caught at the safepoint, and the
4015     // heap is unparseable if they are caught. Grab the Heap_lock
4016     // to prevent this. The GC vm_operations will not be able to
4017     // queue until after the vm thread is dead. After this point,
4018     // we'll never emerge out of the safepoint before the VM exits.
4019 
4020     MutexLocker ml(Heap_lock);
4021 
4022     VMThread::wait_for_vm_thread_exit();
4023     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4024     VMThread::destroy();
4025   }
4026 
4027   // clean up ideal graph printers
4028 #if defined(COMPILER2) && !defined(PRODUCT)
4029   IdealGraphPrinter::clean_up();
4030 #endif
4031 
4032   // Now, all Java threads are gone except daemon threads. Daemon threads
4033   // running Java code or in VM are stopped by the Safepoint. However,
4034   // daemon threads executing native code are still running.  But they
4035   // will be stopped at native=>Java/VM barriers. Note that we can't
4036   // simply kill or suspend them, as it is inherently deadlock-prone.
4037 
4038 #ifndef PRODUCT
4039   // disable function tracing at JNI/JVM barriers
4040   TraceJNICalls = false;
4041   TraceJVMCalls = false;
4042   TraceRuntimeCalls = false;
4043 #endif
4044 
4045   VM_Exit::set_vm_exited();
4046 
4047   notify_vm_shutdown();
4048 
4049   delete thread;
4050 
4051   // exit_globals() will delete tty
4052   exit_globals();
4053 
4054   return true;
4055 }
4056 
4057 
4058 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4059   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4060   return is_supported_jni_version(version);
4061 }
4062 
4063 
4064 jboolean Threads::is_supported_jni_version(jint version) {
4065   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4066   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4067   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4068   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4069   return JNI_FALSE;
4070 }
4071 
4072 
4073 void Threads::add(JavaThread* p, bool force_daemon) {
4074   // The threads lock must be owned at this point
4075   assert_locked_or_safepoint(Threads_lock);
4076 
4077   // See the comment for this method in thread.hpp for its purpose and
4078   // why it is called here.
4079   p->initialize_queues();
4080   p->set_next(_thread_list);
4081   _thread_list = p;
4082   _number_of_threads++;
4083   oop threadObj = p->threadObj();
4084   bool daemon = true;
4085   // Bootstrapping problem: threadObj can be null for initial
4086   // JavaThread (or for threads attached via JNI)
4087   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4088     _number_of_non_daemon_threads++;
4089     daemon = false;
4090   }
4091 
4092   ThreadService::add_thread(p, daemon);
4093 
4094   // Possible GC point.
4095   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4096 }
4097 
4098 void Threads::remove(JavaThread* p) {
4099   // Extra scope needed for Thread_lock, so we can check
4100   // that we do not remove thread without safepoint code notice
4101   { MutexLocker ml(Threads_lock);
4102 
4103     assert(includes(p), "p must be present");
4104 
4105     JavaThread* current = _thread_list;
4106     JavaThread* prev    = NULL;
4107 
4108     while (current != p) {
4109       prev    = current;
4110       current = current->next();
4111     }
4112 
4113     if (prev) {
4114       prev->set_next(current->next());
4115     } else {
4116       _thread_list = p->next();
4117     }
4118     _number_of_threads--;
4119     oop threadObj = p->threadObj();
4120     bool daemon = true;
4121     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4122       _number_of_non_daemon_threads--;
4123       daemon = false;
4124 
4125       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4126       // on destroy_vm will wake up.
4127       if (number_of_non_daemon_threads() == 1)
4128         Threads_lock->notify_all();
4129     }
4130     ThreadService::remove_thread(p, daemon);
4131 
4132     // Make sure that safepoint code disregard this thread. This is needed since
4133     // the thread might mess around with locks after this point. This can cause it
4134     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4135     // of this thread since it is removed from the queue.
4136     p->set_terminated_value();
4137   } // unlock Threads_lock
4138 
4139   // Since Events::log uses a lock, we grab it outside the Threads_lock
4140   Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4141 }
4142 
4143 // Threads_lock must be held when this is called (or must be called during a safepoint)
4144 bool Threads::includes(JavaThread* p) {
4145   assert(Threads_lock->is_locked(), "sanity check");
4146   ALL_JAVA_THREADS(q) {
4147     if (q == p ) {
4148       return true;
4149     }
4150   }
4151   return false;
4152 }
4153 
4154 // Operations on the Threads list for GC.  These are not explicitly locked,
4155 // but the garbage collector must provide a safe context for them to run.
4156 // In particular, these things should never be called when the Threads_lock
4157 // is held by some other thread. (Note: the Safepoint abstraction also
4158 // uses the Threads_lock to gurantee this property. It also makes sure that
4159 // all threads gets blocked when exiting or starting).
4160 
4161 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4162   ALL_JAVA_THREADS(p) {
4163     p->oops_do(f, cld_f, cf);
4164   }
4165   VMThread::vm_thread()->oops_do(f, cld_f, cf);
4166 }
4167 
4168 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4169   // Introduce a mechanism allowing parallel threads to claim threads as
4170   // root groups.  Overhead should be small enough to use all the time,
4171   // even in sequential code.
4172   SharedHeap* sh = SharedHeap::heap();
4173   // Cannot yet substitute active_workers for n_par_threads
4174   // because of G1CollectedHeap::verify() use of
4175   // SharedHeap::process_roots().  n_par_threads == 0 will
4176   // turn off parallelism in process_roots while active_workers
4177   // is being used for parallelism elsewhere.
4178   bool is_par = sh->n_par_threads() > 0;
4179   assert(!is_par ||
4180          (SharedHeap::heap()->n_par_threads() ==
4181           SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4182   int cp = SharedHeap::heap()->strong_roots_parity();
4183   ALL_JAVA_THREADS(p) {
4184     if (p->claim_oops_do(is_par, cp)) {
4185       p->oops_do(f, cld_f, cf);
4186     }
4187   }
4188   VMThread* vmt = VMThread::vm_thread();
4189   if (vmt->claim_oops_do(is_par, cp)) {
4190     vmt->oops_do(f, cld_f, cf);
4191   }
4192 }
4193 
4194 #if INCLUDE_ALL_GCS
4195 // Used by ParallelScavenge
4196 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4197   ALL_JAVA_THREADS(p) {
4198     q->enqueue(new ThreadRootsTask(p));
4199   }
4200   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4201 }
4202 
4203 // Used by Parallel Old
4204 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4205   ALL_JAVA_THREADS(p) {
4206     q->enqueue(new ThreadRootsMarkingTask(p));
4207   }
4208   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4209 }
4210 #endif // INCLUDE_ALL_GCS
4211 
4212 void Threads::nmethods_do(CodeBlobClosure* cf) {
4213   ALL_JAVA_THREADS(p) {
4214     p->nmethods_do(cf);
4215   }
4216   VMThread::vm_thread()->nmethods_do(cf);
4217 }
4218 
4219 void Threads::metadata_do(void f(Metadata*)) {
4220   ALL_JAVA_THREADS(p) {
4221     p->metadata_do(f);
4222   }
4223 }
4224 
4225 void Threads::gc_epilogue() {
4226   ALL_JAVA_THREADS(p) {
4227     p->gc_epilogue();
4228   }
4229 }
4230 
4231 void Threads::gc_prologue() {
4232   ALL_JAVA_THREADS(p) {
4233     p->gc_prologue();
4234   }
4235 }
4236 
4237 void Threads::deoptimized_wrt_marked_nmethods() {
4238   ALL_JAVA_THREADS(p) {
4239     p->deoptimized_wrt_marked_nmethods();
4240   }
4241 }
4242 
4243 
4244 // Get count Java threads that are waiting to enter the specified monitor.
4245 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4246   address monitor, bool doLock) {
4247   assert(doLock || SafepointSynchronize::is_at_safepoint(),
4248     "must grab Threads_lock or be at safepoint");
4249   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4250 
4251   int i = 0;
4252   {
4253     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4254     ALL_JAVA_THREADS(p) {
4255       if (p->is_Compiler_thread()) continue;
4256 
4257       address pending = (address)p->current_pending_monitor();
4258       if (pending == monitor) {             // found a match
4259         if (i < count) result->append(p);   // save the first count matches
4260         i++;
4261       }
4262     }
4263   }
4264   return result;
4265 }
4266 
4267 
4268 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4269   assert(doLock ||
4270          Threads_lock->owned_by_self() ||
4271          SafepointSynchronize::is_at_safepoint(),
4272          "must grab Threads_lock or be at safepoint");
4273 
4274   // NULL owner means not locked so we can skip the search
4275   if (owner == NULL) return NULL;
4276 
4277   {
4278     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4279     ALL_JAVA_THREADS(p) {
4280       // first, see if owner is the address of a Java thread
4281       if (owner == (address)p) return p;
4282     }
4283   }
4284   // Cannot assert on lack of success here since this function may be
4285   // used by code that is trying to report useful problem information
4286   // like deadlock detection.
4287   if (UseHeavyMonitors) return NULL;
4288 
4289   //
4290   // If we didn't find a matching Java thread and we didn't force use of
4291   // heavyweight monitors, then the owner is the stack address of the
4292   // Lock Word in the owning Java thread's stack.
4293   //
4294   JavaThread* the_owner = NULL;
4295   {
4296     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4297     ALL_JAVA_THREADS(q) {
4298       if (q->is_lock_owned(owner)) {
4299         the_owner = q;
4300         break;
4301       }
4302     }
4303   }
4304   // cannot assert on lack of success here; see above comment
4305   return the_owner;
4306 }
4307 
4308 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4309 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4310   char buf[32];
4311   st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4312 
4313   st->print_cr("Full thread dump %s (%s %s):",
4314                 Abstract_VM_Version::vm_name(),
4315                 Abstract_VM_Version::vm_release(),
4316                 Abstract_VM_Version::vm_info_string()
4317                );
4318   st->cr();
4319 
4320 #if INCLUDE_ALL_GCS
4321   // Dump concurrent locks
4322   ConcurrentLocksDump concurrent_locks;
4323   if (print_concurrent_locks) {
4324     concurrent_locks.dump_at_safepoint();
4325   }
4326 #endif // INCLUDE_ALL_GCS
4327 
4328   ALL_JAVA_THREADS(p) {
4329     ResourceMark rm;
4330     p->print_on(st);
4331     if (print_stacks) {
4332       if (internal_format) {
4333         p->trace_stack();
4334       } else {
4335         p->print_stack_on(st);
4336       }
4337     }
4338     st->cr();
4339 #if INCLUDE_ALL_GCS
4340     if (print_concurrent_locks) {
4341       concurrent_locks.print_locks_on(p, st);
4342     }
4343 #endif // INCLUDE_ALL_GCS
4344   }
4345 
4346   VMThread::vm_thread()->print_on(st);
4347   st->cr();
4348   Universe::heap()->print_gc_threads_on(st);
4349   WatcherThread* wt = WatcherThread::watcher_thread();
4350   if (wt != NULL) {
4351     wt->print_on(st);
4352     st->cr();
4353   }
4354   CompileBroker::print_compiler_threads_on(st);
4355   st->flush();
4356 }
4357 
4358 // Threads::print_on_error() is called by fatal error handler. It's possible
4359 // that VM is not at safepoint and/or current thread is inside signal handler.
4360 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4361 // memory (even in resource area), it might deadlock the error handler.
4362 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4363   bool found_current = false;
4364   st->print_cr("Java Threads: ( => current thread )");
4365   ALL_JAVA_THREADS(thread) {
4366     bool is_current = (current == thread);
4367     found_current = found_current || is_current;
4368 
4369     st->print("%s", is_current ? "=>" : "  ");
4370 
4371     st->print(PTR_FORMAT, thread);
4372     st->print(" ");
4373     thread->print_on_error(st, buf, buflen);
4374     st->cr();
4375   }
4376   st->cr();
4377 
4378   st->print_cr("Other Threads:");
4379   if (VMThread::vm_thread()) {
4380     bool is_current = (current == VMThread::vm_thread());
4381     found_current = found_current || is_current;
4382     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
4383 
4384     st->print(PTR_FORMAT, VMThread::vm_thread());
4385     st->print(" ");
4386     VMThread::vm_thread()->print_on_error(st, buf, buflen);
4387     st->cr();
4388   }
4389   WatcherThread* wt = WatcherThread::watcher_thread();
4390   if (wt != NULL) {
4391     bool is_current = (current == wt);
4392     found_current = found_current || is_current;
4393     st->print("%s", is_current ? "=>" : "  ");
4394 
4395     st->print(PTR_FORMAT, wt);
4396     st->print(" ");
4397     wt->print_on_error(st, buf, buflen);
4398     st->cr();
4399   }
4400   if (!found_current) {
4401     st->cr();
4402     st->print("=>" PTR_FORMAT " (exited) ", current);
4403     current->print_on_error(st, buf, buflen);
4404     st->cr();
4405   }
4406 }
4407 
4408 // Internal SpinLock and Mutex
4409 // Based on ParkEvent
4410 
4411 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4412 //
4413 // We employ SpinLocks _only for low-contention, fixed-length
4414 // short-duration critical sections where we're concerned
4415 // about native mutex_t or HotSpot Mutex:: latency.
4416 // The mux construct provides a spin-then-block mutual exclusion
4417 // mechanism.
4418 //
4419 // Testing has shown that contention on the ListLock guarding gFreeList
4420 // is common.  If we implement ListLock as a simple SpinLock it's common
4421 // for the JVM to devolve to yielding with little progress.  This is true
4422 // despite the fact that the critical sections protected by ListLock are
4423 // extremely short.
4424 //
4425 // TODO-FIXME: ListLock should be of type SpinLock.
4426 // We should make this a 1st-class type, integrated into the lock
4427 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4428 // should have sufficient padding to avoid false-sharing and excessive
4429 // cache-coherency traffic.
4430 
4431 
4432 typedef volatile int SpinLockT ;
4433 
4434 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4435   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4436      return ;   // normal fast-path return
4437   }
4438 
4439   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4440   TEVENT (SpinAcquire - ctx) ;
4441   int ctr = 0 ;
4442   int Yields = 0 ;
4443   for (;;) {
4444      while (*adr != 0) {
4445         ++ctr ;
4446         if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4447            if (Yields > 5) {
4448              os::naked_short_sleep(1);
4449            } else {
4450              os::NakedYield() ;
4451              ++Yields ;
4452            }
4453         } else {
4454            SpinPause() ;
4455         }
4456      }
4457      if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4458   }
4459 }
4460 
4461 void Thread::SpinRelease (volatile int * adr) {
4462   assert (*adr != 0, "invariant") ;
4463   OrderAccess::fence() ;      // guarantee at least release consistency.
4464   // Roach-motel semantics.
4465   // It's safe if subsequent LDs and STs float "up" into the critical section,
4466   // but prior LDs and STs within the critical section can't be allowed
4467   // to reorder or float past the ST that releases the lock.
4468   *adr = 0 ;
4469 }
4470 
4471 // muxAcquire and muxRelease:
4472 //
4473 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4474 //    The LSB of the word is set IFF the lock is held.
4475 //    The remainder of the word points to the head of a singly-linked list
4476 //    of threads blocked on the lock.
4477 //
4478 // *  The current implementation of muxAcquire-muxRelease uses its own
4479 //    dedicated Thread._MuxEvent instance.  If we're interested in
4480 //    minimizing the peak number of extant ParkEvent instances then
4481 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4482 //    as certain invariants were satisfied.  Specifically, care would need
4483 //    to be taken with regards to consuming unpark() "permits".
4484 //    A safe rule of thumb is that a thread would never call muxAcquire()
4485 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4486 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4487 //    consume an unpark() permit intended for monitorenter, for instance.
4488 //    One way around this would be to widen the restricted-range semaphore
4489 //    implemented in park().  Another alternative would be to provide
4490 //    multiple instances of the PlatformEvent() for each thread.  One
4491 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4492 //
4493 // *  Usage:
4494 //    -- Only as leaf locks
4495 //    -- for short-term locking only as muxAcquire does not perform
4496 //       thread state transitions.
4497 //
4498 // Alternatives:
4499 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4500 //    but with parking or spin-then-park instead of pure spinning.
4501 // *  Use Taura-Oyama-Yonenzawa locks.
4502 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4503 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4504 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4505 //    acquiring threads use timers (ParkTimed) to detect and recover from
4506 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4507 //    boundaries by using placement-new.
4508 // *  Augment MCS with advisory back-link fields maintained with CAS().
4509 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4510 //    The validity of the backlinks must be ratified before we trust the value.
4511 //    If the backlinks are invalid the exiting thread must back-track through the
4512 //    the forward links, which are always trustworthy.
4513 // *  Add a successor indication.  The LockWord is currently encoded as
4514 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4515 //    to provide the usual futile-wakeup optimization.
4516 //    See RTStt for details.
4517 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4518 //
4519 
4520 
4521 typedef volatile intptr_t MutexT ;      // Mux Lock-word
4522 enum MuxBits { LOCKBIT = 1 } ;
4523 
4524 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4525   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4526   if (w == 0) return ;
4527   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4528      return ;
4529   }
4530 
4531   TEVENT (muxAcquire - Contention) ;
4532   ParkEvent * const Self = Thread::current()->_MuxEvent ;
4533   assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4534   for (;;) {
4535      int its = (os::is_MP() ? 100 : 0) + 1 ;
4536 
4537      // Optional spin phase: spin-then-park strategy
4538      while (--its >= 0) {
4539        w = *Lock ;
4540        if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4541           return ;
4542        }
4543      }
4544 
4545      Self->reset() ;
4546      Self->OnList = intptr_t(Lock) ;
4547      // The following fence() isn't _strictly necessary as the subsequent
4548      // CAS() both serializes execution and ratifies the fetched *Lock value.
4549      OrderAccess::fence();
4550      for (;;) {
4551         w = *Lock ;
4552         if ((w & LOCKBIT) == 0) {
4553             if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4554                 Self->OnList = 0 ;   // hygiene - allows stronger asserts
4555                 return ;
4556             }
4557             continue ;      // Interference -- *Lock changed -- Just retry
4558         }
4559         assert (w & LOCKBIT, "invariant") ;
4560         Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4561         if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4562      }
4563 
4564      while (Self->OnList != 0) {
4565         Self->park() ;
4566      }
4567   }
4568 }
4569 
4570 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4571   intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4572   if (w == 0) return ;
4573   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4574     return ;
4575   }
4576 
4577   TEVENT (muxAcquire - Contention) ;
4578   ParkEvent * ReleaseAfter = NULL ;
4579   if (ev == NULL) {
4580     ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4581   }
4582   assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4583   for (;;) {
4584     guarantee (ev->OnList == 0, "invariant") ;
4585     int its = (os::is_MP() ? 100 : 0) + 1 ;
4586 
4587     // Optional spin phase: spin-then-park strategy
4588     while (--its >= 0) {
4589       w = *Lock ;
4590       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4591         if (ReleaseAfter != NULL) {
4592           ParkEvent::Release (ReleaseAfter) ;
4593         }
4594         return ;
4595       }
4596     }
4597 
4598     ev->reset() ;
4599     ev->OnList = intptr_t(Lock) ;
4600     // The following fence() isn't _strictly necessary as the subsequent
4601     // CAS() both serializes execution and ratifies the fetched *Lock value.
4602     OrderAccess::fence();
4603     for (;;) {
4604       w = *Lock ;
4605       if ((w & LOCKBIT) == 0) {
4606         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4607           ev->OnList = 0 ;
4608           // We call ::Release while holding the outer lock, thus
4609           // artificially lengthening the critical section.
4610           // Consider deferring the ::Release() until the subsequent unlock(),
4611           // after we've dropped the outer lock.
4612           if (ReleaseAfter != NULL) {
4613             ParkEvent::Release (ReleaseAfter) ;
4614           }
4615           return ;
4616         }
4617         continue ;      // Interference -- *Lock changed -- Just retry
4618       }
4619       assert (w & LOCKBIT, "invariant") ;
4620       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4621       if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4622     }
4623 
4624     while (ev->OnList != 0) {
4625       ev->park() ;
4626     }
4627   }
4628 }
4629 
4630 // Release() must extract a successor from the list and then wake that thread.
4631 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4632 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4633 // Release() would :
4634 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4635 // (B) Extract a successor from the private list "in-hand"
4636 // (C) attempt to CAS() the residual back into *Lock over null.
4637 //     If there were any newly arrived threads and the CAS() would fail.
4638 //     In that case Release() would detach the RATs, re-merge the list in-hand
4639 //     with the RATs and repeat as needed.  Alternately, Release() might
4640 //     detach and extract a successor, but then pass the residual list to the wakee.
4641 //     The wakee would be responsible for reattaching and remerging before it
4642 //     competed for the lock.
4643 //
4644 // Both "pop" and DMR are immune from ABA corruption -- there can be
4645 // multiple concurrent pushers, but only one popper or detacher.
4646 // This implementation pops from the head of the list.  This is unfair,
4647 // but tends to provide excellent throughput as hot threads remain hot.
4648 // (We wake recently run threads first).
4649 
4650 void Thread::muxRelease (volatile intptr_t * Lock)  {
4651   for (;;) {
4652     const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4653     assert (w & LOCKBIT, "invariant") ;
4654     if (w == LOCKBIT) return ;
4655     ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4656     assert (List != NULL, "invariant") ;
4657     assert (List->OnList == intptr_t(Lock), "invariant") ;
4658     ParkEvent * nxt = List->ListNext ;
4659 
4660     // The following CAS() releases the lock and pops the head element.
4661     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4662       continue ;
4663     }
4664     List->OnList = 0 ;
4665     OrderAccess::fence() ;
4666     List->unpark () ;
4667     return ;
4668   }
4669 }
4670 
4671 
4672 void Threads::verify() {
4673   ALL_JAVA_THREADS(p) {
4674     p->verify();
4675   }
4676   VMThread* thread = VMThread::vm_thread();
4677   if (thread != NULL) thread->verify();
4678 }