1 /*
   2  * Copyright (c) 1997, 2015, 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/codeCache.hpp"
  31 #include "code/codeCacheExtensions.hpp"
  32 #include "code/scopeDesc.hpp"
  33 #include "compiler/compileBroker.hpp"
  34 #include "gc/shared/gcLocker.inline.hpp"
  35 #include "gc/shared/workgroup.hpp"
  36 #include "interpreter/interpreter.hpp"
  37 #include "interpreter/linkResolver.hpp"
  38 #include "interpreter/oopMapCache.hpp"
  39 #include "jvmtifiles/jvmtiEnv.hpp"
  40 #include "memory/metaspaceShared.hpp"
  41 #include "memory/oopFactory.hpp"
  42 #include "memory/universe.inline.hpp"
  43 #include "oops/instanceKlass.hpp"
  44 #include "oops/objArrayOop.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "oops/symbol.hpp"
  47 #include "oops/verifyOopClosure.hpp"
  48 #include "prims/jvm_misc.hpp"
  49 #include "prims/jvmtiExport.hpp"
  50 #include "prims/jvmtiThreadState.hpp"
  51 #include "prims/privilegedStack.hpp"
  52 #include "runtime/arguments.hpp"
  53 #include "runtime/atomic.inline.hpp"
  54 #include "runtime/biasedLocking.hpp"
  55 #include "runtime/commandLineFlagConstraintList.hpp"
  56 #include "runtime/commandLineFlagRangeList.hpp"
  57 #include "runtime/deoptimization.hpp"
  58 #include "runtime/fprofiler.hpp"
  59 #include "runtime/frame.inline.hpp"
  60 #include "runtime/globals.hpp"
  61 #include "runtime/init.hpp"
  62 #include "runtime/interfaceSupport.hpp"
  63 #include "runtime/java.hpp"
  64 #include "runtime/javaCalls.hpp"
  65 #include "runtime/jniPeriodicChecker.hpp"
  66 #include "runtime/memprofiler.hpp"
  67 #include "runtime/mutexLocker.hpp"
  68 #include "runtime/objectMonitor.hpp"
  69 #include "runtime/orderAccess.inline.hpp"
  70 #include "runtime/osThread.hpp"
  71 #include "runtime/safepoint.hpp"
  72 #include "runtime/sharedRuntime.hpp"
  73 #include "runtime/statSampler.hpp"
  74 #include "runtime/stubRoutines.hpp"
  75 #include "runtime/sweeper.hpp"
  76 #include "runtime/task.hpp"
  77 #include "runtime/thread.inline.hpp"
  78 #include "runtime/threadCritical.hpp"
  79 #include "runtime/threadLocalStorage.hpp"
  80 #include "runtime/vframe.hpp"
  81 #include "runtime/vframeArray.hpp"
  82 #include "runtime/vframe_hp.hpp"
  83 #include "runtime/vmThread.hpp"
  84 #include "runtime/vm_operations.hpp"
  85 #include "runtime/vm_version.hpp"
  86 #include "services/attachListener.hpp"
  87 #include "services/management.hpp"
  88 #include "services/memTracker.hpp"
  89 #include "services/threadService.hpp"
  90 #include "trace/traceMacros.hpp"
  91 #include "trace/tracing.hpp"
  92 #include "utilities/defaultStream.hpp"
  93 #include "utilities/dtrace.hpp"
  94 #include "utilities/events.hpp"
  95 #include "utilities/macros.hpp"
  96 #include "utilities/preserveException.hpp"
  97 #if INCLUDE_ALL_GCS
  98 #include "gc/cms/concurrentMarkSweepThread.hpp"
  99 #include "gc/g1/concurrentMarkThread.inline.hpp"
 100 #include "gc/parallel/pcTasks.hpp"
 101 #endif // INCLUDE_ALL_GCS
 102 #if INCLUDE_JVMCI
 103 #include "jvmci/jvmciCompiler.hpp"
 104 #include "jvmci/jvmciRuntime.hpp"
 105 #endif
 106 #ifdef COMPILER1
 107 #include "c1/c1_Compiler.hpp"
 108 #endif
 109 #ifdef COMPILER2
 110 #include "opto/c2compiler.hpp"
 111 #include "opto/idealGraphPrinter.hpp"
 112 #endif
 113 #if INCLUDE_RTM_OPT
 114 #include "runtime/rtmLocking.hpp"
 115 #endif
 116 
 117 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 118 
 119 #ifdef DTRACE_ENABLED
 120 
 121 // Only bother with this argument setup if dtrace is available
 122 
 123   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 124   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 125 
 126   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 127     {                                                                      \
 128       ResourceMark rm(this);                                               \
 129       int len = 0;                                                         \
 130       const char* name = (javathread)->get_thread_name();                  \
 131       len = strlen(name);                                                  \
 132       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 133         (char *) name, len,                                                \
 134         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 135         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 136         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 137     }
 138 
 139 #else //  ndef DTRACE_ENABLED
 140 
 141   #define DTRACE_THREAD_PROBE(probe, javathread)
 142 
 143 #endif // ndef DTRACE_ENABLED
 144 
 145 
 146 // Class hierarchy
 147 // - Thread
 148 //   - VMThread
 149 //   - WatcherThread
 150 //   - ConcurrentMarkSweepThread
 151 //   - JavaThread
 152 //     - CompilerThread
 153 
 154 // ======= Thread ========
 155 // Support for forcing alignment of thread objects for biased locking
 156 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 157   if (UseBiasedLocking) {
 158     const int alignment = markOopDesc::biased_lock_alignment;
 159     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 160     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 161                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 162                                                          AllocFailStrategy::RETURN_NULL);
 163     void* aligned_addr     = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
 164     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 165            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 166            "JavaThread alignment code overflowed allocated storage");
 167     if (TraceBiasedLocking) {
 168       if (aligned_addr != real_malloc_addr) {
 169         tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 170                       real_malloc_addr, aligned_addr);
 171       }
 172     }
 173     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 174     return aligned_addr;
 175   } else {
 176     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 177                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 178   }
 179 }
 180 
 181 void Thread::operator delete(void* p) {
 182   if (UseBiasedLocking) {
 183     void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
 184     FreeHeap(real_malloc_addr);
 185   } else {
 186     FreeHeap(p);
 187   }
 188 }
 189 
 190 
 191 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 192 // JavaThread
 193 
 194 
 195 Thread::Thread() {
 196   // stack and get_thread
 197   set_stack_base(NULL);
 198   set_stack_size(0);
 199   set_self_raw_id(0);
 200   set_lgrp_id(-1);
 201   DEBUG_ONLY(clear_suspendible_thread();)
 202 
 203   // allocated data structures
 204   set_osthread(NULL);
 205   set_resource_area(new (mtThread)ResourceArea());
 206   DEBUG_ONLY(_current_resource_mark = NULL;)
 207   set_handle_area(new (mtThread) HandleArea(NULL));
 208   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 209   set_active_handles(NULL);
 210   set_free_handle_block(NULL);
 211   set_last_handle_mark(NULL);
 212 
 213   // This initial value ==> never claimed.
 214   _oops_do_parity = 0;
 215 
 216   // the handle mark links itself to last_handle_mark
 217   new HandleMark(this);
 218 
 219   // plain initialization
 220   debug_only(_owned_locks = NULL;)
 221   debug_only(_allow_allocation_count = 0;)
 222   NOT_PRODUCT(_allow_safepoint_count = 0;)
 223   NOT_PRODUCT(_skip_gcalot = false;)
 224   _jvmti_env_iteration_count = 0;
 225   set_allocated_bytes(0);
 226   _vm_operation_started_count = 0;
 227   _vm_operation_completed_count = 0;
 228   _current_pending_monitor = NULL;
 229   _current_pending_monitor_is_from_java = true;
 230   _current_waiting_monitor = NULL;
 231   _num_nested_signal = 0;
 232   omFreeList = NULL;
 233   omFreeCount = 0;
 234   omFreeProvision = 32;
 235   omInUseList = NULL;
 236   omInUseCount = 0;
 237 
 238 #ifdef ASSERT
 239   _visited_for_critical_count = false;
 240 #endif
 241 
 242   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
 243                          Monitor::_safepoint_check_sometimes);
 244   _suspend_flags = 0;
 245 
 246   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 247   _hashStateX = os::random();
 248   _hashStateY = 842502087;
 249   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 250   _hashStateW = 273326509;
 251 
 252   _OnTrap   = 0;
 253   _schedctl = NULL;
 254   _Stalled  = 0;
 255   _TypeTag  = 0x2BAD;
 256 
 257   // Many of the following fields are effectively final - immutable
 258   // Note that nascent threads can't use the Native Monitor-Mutex
 259   // construct until the _MutexEvent is initialized ...
 260   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 261   // we might instead use a stack of ParkEvents that we could provision on-demand.
 262   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 263   // and ::Release()
 264   _ParkEvent   = ParkEvent::Allocate(this);
 265   _SleepEvent  = ParkEvent::Allocate(this);
 266   _MutexEvent  = ParkEvent::Allocate(this);
 267   _MuxEvent    = ParkEvent::Allocate(this);
 268 
 269 #ifdef CHECK_UNHANDLED_OOPS
 270   if (CheckUnhandledOops) {
 271     _unhandled_oops = new UnhandledOops(this);
 272   }
 273 #endif // CHECK_UNHANDLED_OOPS
 274 #ifdef ASSERT
 275   if (UseBiasedLocking) {
 276     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 277     assert(this == _real_malloc_address ||
 278            this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
 279            "bug in forced alignment of thread objects");
 280   }
 281 #endif // ASSERT
 282 }
 283 
 284 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
 285 Thread* Thread::current_noinline() {
 286   return Thread::current();
 287 }
 288 
 289 void Thread::initialize_thread_local_storage() {
 290   // Note: Make sure this method only calls
 291   // non-blocking operations. Otherwise, it might not work
 292   // with the thread-startup/safepoint interaction.
 293 
 294   // During Java thread startup, safepoint code should allow this
 295   // method to complete because it may need to allocate memory to
 296   // store information for the new thread.
 297 
 298   // initialize structure dependent on thread local storage
 299   ThreadLocalStorage::set_thread(this);
 300 }
 301 
 302 void Thread::record_stack_base_and_size() {
 303   set_stack_base(os::current_stack_base());
 304   set_stack_size(os::current_stack_size());
 305   if (is_Java_thread()) {
 306     ((JavaThread*) this)->set_stack_overflow_limit();
 307   }
 308   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 309   // in initialize_thread(). Without the adjustment, stack size is
 310   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 311   // So far, only Solaris has real implementation of initialize_thread().
 312   //
 313   // set up any platform-specific state.
 314   os::initialize_thread(this);
 315 
 316 #if INCLUDE_NMT
 317   // record thread's native stack, stack grows downward
 318   address stack_low_addr = stack_base() - stack_size();
 319   MemTracker::record_thread_stack(stack_low_addr, stack_size());
 320 #endif // INCLUDE_NMT
 321 }
 322 
 323 
 324 Thread::~Thread() {
 325   // Reclaim the objectmonitors from the omFreeList of the moribund thread.
 326   ObjectSynchronizer::omFlush(this);
 327 
 328   EVENT_THREAD_DESTRUCT(this);
 329 
 330   // stack_base can be NULL if the thread is never started or exited before
 331   // record_stack_base_and_size called. Although, we would like to ensure
 332   // that all started threads do call record_stack_base_and_size(), there is
 333   // not proper way to enforce that.
 334 #if INCLUDE_NMT
 335   if (_stack_base != NULL) {
 336     address low_stack_addr = stack_base() - stack_size();
 337     MemTracker::release_thread_stack(low_stack_addr, stack_size());
 338 #ifdef ASSERT
 339     set_stack_base(NULL);
 340 #endif
 341   }
 342 #endif // INCLUDE_NMT
 343 
 344   // deallocate data structures
 345   delete resource_area();
 346   // since the handle marks are using the handle area, we have to deallocated the root
 347   // handle mark before deallocating the thread's handle area,
 348   assert(last_handle_mark() != NULL, "check we have an element");
 349   delete last_handle_mark();
 350   assert(last_handle_mark() == NULL, "check we have reached the end");
 351 
 352   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 353   // We NULL out the fields for good hygiene.
 354   ParkEvent::Release(_ParkEvent); _ParkEvent   = NULL;
 355   ParkEvent::Release(_SleepEvent); _SleepEvent  = NULL;
 356   ParkEvent::Release(_MutexEvent); _MutexEvent  = NULL;
 357   ParkEvent::Release(_MuxEvent); _MuxEvent    = NULL;
 358 
 359   delete handle_area();
 360   delete metadata_handles();
 361 
 362   // osthread() can be NULL, if creation of thread failed.
 363   if (osthread() != NULL) os::free_thread(osthread());
 364 
 365   delete _SR_lock;
 366 
 367   // clear thread local storage if the Thread is deleting itself
 368   if (this == Thread::current()) {
 369     ThreadLocalStorage::set_thread(NULL);
 370   } else {
 371     // In the case where we're not the current thread, invalidate all the
 372     // caches in case some code tries to get the current thread or the
 373     // thread that was destroyed, and gets stale information.
 374     ThreadLocalStorage::invalidate_all();
 375   }
 376   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 377 }
 378 
 379 // NOTE: dummy function for assertion purpose.
 380 void Thread::run() {
 381   ShouldNotReachHere();
 382 }
 383 
 384 #ifdef ASSERT
 385 // Private method to check for dangling thread pointer
 386 void check_for_dangling_thread_pointer(Thread *thread) {
 387   assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
 388          "possibility of dangling Thread pointer");
 389 }
 390 #endif
 391 
 392 ThreadPriority Thread::get_priority(const Thread* const thread) {
 393   ThreadPriority priority;
 394   // Can return an error!
 395   (void)os::get_priority(thread, priority);
 396   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 397   return priority;
 398 }
 399 
 400 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 401   debug_only(check_for_dangling_thread_pointer(thread);)
 402   // Can return an error!
 403   (void)os::set_priority(thread, priority);
 404 }
 405 
 406 
 407 void Thread::start(Thread* thread) {
 408   // Start is different from resume in that its safety is guaranteed by context or
 409   // being called from a Java method synchronized on the Thread object.
 410   if (!DisableStartThread) {
 411     if (thread->is_Java_thread()) {
 412       // Initialize the thread state to RUNNABLE before starting this thread.
 413       // Can not set it after the thread started because we do not know the
 414       // exact thread state at that time. It could be in MONITOR_WAIT or
 415       // in SLEEPING or some other state.
 416       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 417                                           java_lang_Thread::RUNNABLE);
 418     }
 419     os::start_thread(thread);
 420   }
 421 }
 422 
 423 // Enqueue a VM_Operation to do the job for us - sometime later
 424 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 425   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 426   VMThread::execute(vm_stop);
 427 }
 428 
 429 
 430 // Check if an external suspend request has completed (or has been
 431 // cancelled). Returns true if the thread is externally suspended and
 432 // false otherwise.
 433 //
 434 // The bits parameter returns information about the code path through
 435 // the routine. Useful for debugging:
 436 //
 437 // set in is_ext_suspend_completed():
 438 // 0x00000001 - routine was entered
 439 // 0x00000010 - routine return false at end
 440 // 0x00000100 - thread exited (return false)
 441 // 0x00000200 - suspend request cancelled (return false)
 442 // 0x00000400 - thread suspended (return true)
 443 // 0x00001000 - thread is in a suspend equivalent state (return true)
 444 // 0x00002000 - thread is native and walkable (return true)
 445 // 0x00004000 - thread is native_trans and walkable (needed retry)
 446 //
 447 // set in wait_for_ext_suspend_completion():
 448 // 0x00010000 - routine was entered
 449 // 0x00020000 - suspend request cancelled before loop (return false)
 450 // 0x00040000 - thread suspended before loop (return true)
 451 // 0x00080000 - suspend request cancelled in loop (return false)
 452 // 0x00100000 - thread suspended in loop (return true)
 453 // 0x00200000 - suspend not completed during retry loop (return false)
 454 
 455 // Helper class for tracing suspend wait debug bits.
 456 //
 457 // 0x00000100 indicates that the target thread exited before it could
 458 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 459 // 0x00080000 each indicate a cancelled suspend request so they don't
 460 // count as wait failures either.
 461 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 462 
 463 class TraceSuspendDebugBits : public StackObj {
 464  private:
 465   JavaThread * jt;
 466   bool         is_wait;
 467   bool         called_by_wait;  // meaningful when !is_wait
 468   uint32_t *   bits;
 469 
 470  public:
 471   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 472                         uint32_t *_bits) {
 473     jt             = _jt;
 474     is_wait        = _is_wait;
 475     called_by_wait = _called_by_wait;
 476     bits           = _bits;
 477   }
 478 
 479   ~TraceSuspendDebugBits() {
 480     if (!is_wait) {
 481 #if 1
 482       // By default, don't trace bits for is_ext_suspend_completed() calls.
 483       // That trace is very chatty.
 484       return;
 485 #else
 486       if (!called_by_wait) {
 487         // If tracing for is_ext_suspend_completed() is enabled, then only
 488         // trace calls to it from wait_for_ext_suspend_completion()
 489         return;
 490       }
 491 #endif
 492     }
 493 
 494     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 495       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 496         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 497         ResourceMark rm;
 498 
 499         tty->print_cr(
 500                       "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 501                       jt->get_thread_name(), *bits);
 502 
 503         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 504       }
 505     }
 506   }
 507 };
 508 #undef DEBUG_FALSE_BITS
 509 
 510 
 511 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
 512                                           uint32_t *bits) {
 513   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 514 
 515   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 516   bool do_trans_retry;           // flag to force the retry
 517 
 518   *bits |= 0x00000001;
 519 
 520   do {
 521     do_trans_retry = false;
 522 
 523     if (is_exiting()) {
 524       // Thread is in the process of exiting. This is always checked
 525       // first to reduce the risk of dereferencing a freed JavaThread.
 526       *bits |= 0x00000100;
 527       return false;
 528     }
 529 
 530     if (!is_external_suspend()) {
 531       // Suspend request is cancelled. This is always checked before
 532       // is_ext_suspended() to reduce the risk of a rogue resume
 533       // confusing the thread that made the suspend request.
 534       *bits |= 0x00000200;
 535       return false;
 536     }
 537 
 538     if (is_ext_suspended()) {
 539       // thread is suspended
 540       *bits |= 0x00000400;
 541       return true;
 542     }
 543 
 544     // Now that we no longer do hard suspends of threads running
 545     // native code, the target thread can be changing thread state
 546     // while we are in this routine:
 547     //
 548     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 549     //
 550     // We save a copy of the thread state as observed at this moment
 551     // and make our decision about suspend completeness based on the
 552     // copy. This closes the race where the thread state is seen as
 553     // _thread_in_native_trans in the if-thread_blocked check, but is
 554     // seen as _thread_blocked in if-thread_in_native_trans check.
 555     JavaThreadState save_state = thread_state();
 556 
 557     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 558       // If the thread's state is _thread_blocked and this blocking
 559       // condition is known to be equivalent to a suspend, then we can
 560       // consider the thread to be externally suspended. This means that
 561       // the code that sets _thread_blocked has been modified to do
 562       // self-suspension if the blocking condition releases. We also
 563       // used to check for CONDVAR_WAIT here, but that is now covered by
 564       // the _thread_blocked with self-suspension check.
 565       //
 566       // Return true since we wouldn't be here unless there was still an
 567       // external suspend request.
 568       *bits |= 0x00001000;
 569       return true;
 570     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 571       // Threads running native code will self-suspend on native==>VM/Java
 572       // transitions. If its stack is walkable (should always be the case
 573       // unless this function is called before the actual java_suspend()
 574       // call), then the wait is done.
 575       *bits |= 0x00002000;
 576       return true;
 577     } else if (!called_by_wait && !did_trans_retry &&
 578                save_state == _thread_in_native_trans &&
 579                frame_anchor()->walkable()) {
 580       // The thread is transitioning from thread_in_native to another
 581       // thread state. check_safepoint_and_suspend_for_native_trans()
 582       // will force the thread to self-suspend. If it hasn't gotten
 583       // there yet we may have caught the thread in-between the native
 584       // code check above and the self-suspend. Lucky us. If we were
 585       // called by wait_for_ext_suspend_completion(), then it
 586       // will be doing the retries so we don't have to.
 587       //
 588       // Since we use the saved thread state in the if-statement above,
 589       // there is a chance that the thread has already transitioned to
 590       // _thread_blocked by the time we get here. In that case, we will
 591       // make a single unnecessary pass through the logic below. This
 592       // doesn't hurt anything since we still do the trans retry.
 593 
 594       *bits |= 0x00004000;
 595 
 596       // Once the thread leaves thread_in_native_trans for another
 597       // thread state, we break out of this retry loop. We shouldn't
 598       // need this flag to prevent us from getting back here, but
 599       // sometimes paranoia is good.
 600       did_trans_retry = true;
 601 
 602       // We wait for the thread to transition to a more usable state.
 603       for (int i = 1; i <= SuspendRetryCount; i++) {
 604         // We used to do an "os::yield_all(i)" call here with the intention
 605         // that yielding would increase on each retry. However, the parameter
 606         // is ignored on Linux which means the yield didn't scale up. Waiting
 607         // on the SR_lock below provides a much more predictable scale up for
 608         // the delay. It also provides a simple/direct point to check for any
 609         // safepoint requests from the VMThread
 610 
 611         // temporarily drops SR_lock while doing wait with safepoint check
 612         // (if we're a JavaThread - the WatcherThread can also call this)
 613         // and increase delay with each retry
 614         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 615 
 616         // check the actual thread state instead of what we saved above
 617         if (thread_state() != _thread_in_native_trans) {
 618           // the thread has transitioned to another thread state so
 619           // try all the checks (except this one) one more time.
 620           do_trans_retry = true;
 621           break;
 622         }
 623       } // end retry loop
 624 
 625 
 626     }
 627   } while (do_trans_retry);
 628 
 629   *bits |= 0x00000010;
 630   return false;
 631 }
 632 
 633 // Wait for an external suspend request to complete (or be cancelled).
 634 // Returns true if the thread is externally suspended and false otherwise.
 635 //
 636 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 637                                                  uint32_t *bits) {
 638   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 639                              false /* !called_by_wait */, bits);
 640 
 641   // local flag copies to minimize SR_lock hold time
 642   bool is_suspended;
 643   bool pending;
 644   uint32_t reset_bits;
 645 
 646   // set a marker so is_ext_suspend_completed() knows we are the caller
 647   *bits |= 0x00010000;
 648 
 649   // We use reset_bits to reinitialize the bits value at the top of
 650   // each retry loop. This allows the caller to make use of any
 651   // unused bits for their own marking purposes.
 652   reset_bits = *bits;
 653 
 654   {
 655     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 656     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 657                                             delay, bits);
 658     pending = is_external_suspend();
 659   }
 660   // must release SR_lock to allow suspension to complete
 661 
 662   if (!pending) {
 663     // A cancelled suspend request is the only false return from
 664     // is_ext_suspend_completed() that keeps us from entering the
 665     // retry loop.
 666     *bits |= 0x00020000;
 667     return false;
 668   }
 669 
 670   if (is_suspended) {
 671     *bits |= 0x00040000;
 672     return true;
 673   }
 674 
 675   for (int i = 1; i <= retries; i++) {
 676     *bits = reset_bits;  // reinit to only track last retry
 677 
 678     // We used to do an "os::yield_all(i)" call here with the intention
 679     // that yielding would increase on each retry. However, the parameter
 680     // is ignored on Linux which means the yield didn't scale up. Waiting
 681     // on the SR_lock below provides a much more predictable scale up for
 682     // the delay. It also provides a simple/direct point to check for any
 683     // safepoint requests from the VMThread
 684 
 685     {
 686       MutexLocker ml(SR_lock());
 687       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 688       // can also call this)  and increase delay with each retry
 689       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 690 
 691       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 692                                               delay, bits);
 693 
 694       // It is possible for the external suspend request to be cancelled
 695       // (by a resume) before the actual suspend operation is completed.
 696       // Refresh our local copy to see if we still need to wait.
 697       pending = is_external_suspend();
 698     }
 699 
 700     if (!pending) {
 701       // A cancelled suspend request is the only false return from
 702       // is_ext_suspend_completed() that keeps us from staying in the
 703       // retry loop.
 704       *bits |= 0x00080000;
 705       return false;
 706     }
 707 
 708     if (is_suspended) {
 709       *bits |= 0x00100000;
 710       return true;
 711     }
 712   } // end retry loop
 713 
 714   // thread did not suspend after all our retries
 715   *bits |= 0x00200000;
 716   return false;
 717 }
 718 
 719 #ifndef PRODUCT
 720 void JavaThread::record_jump(address target, address instr, const char* file,
 721                              int line) {
 722 
 723   // This should not need to be atomic as the only way for simultaneous
 724   // updates is via interrupts. Even then this should be rare or non-existent
 725   // and we don't care that much anyway.
 726 
 727   int index = _jmp_ring_index;
 728   _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
 729   _jmp_ring[index]._target = (intptr_t) target;
 730   _jmp_ring[index]._instruction = (intptr_t) instr;
 731   _jmp_ring[index]._file = file;
 732   _jmp_ring[index]._line = line;
 733 }
 734 #endif // PRODUCT
 735 
 736 // Called by flat profiler
 737 // Callers have already called wait_for_ext_suspend_completion
 738 // The assertion for that is currently too complex to put here:
 739 bool JavaThread::profile_last_Java_frame(frame* _fr) {
 740   bool gotframe = false;
 741   // self suspension saves needed state.
 742   if (has_last_Java_frame() && _anchor.walkable()) {
 743     *_fr = pd_last_frame();
 744     gotframe = true;
 745   }
 746   return gotframe;
 747 }
 748 
 749 void Thread::interrupt(Thread* thread) {
 750   debug_only(check_for_dangling_thread_pointer(thread);)
 751   os::interrupt(thread);
 752 }
 753 
 754 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 755   debug_only(check_for_dangling_thread_pointer(thread);)
 756   // Note:  If clear_interrupted==false, this simply fetches and
 757   // returns the value of the field osthread()->interrupted().
 758   return os::is_interrupted(thread, clear_interrupted);
 759 }
 760 
 761 
 762 // GC Support
 763 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 764   jint thread_parity = _oops_do_parity;
 765   if (thread_parity != strong_roots_parity) {
 766     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 767     if (res == thread_parity) {
 768       return true;
 769     } else {
 770       guarantee(res == strong_roots_parity, "Or else what?");
 771       return false;
 772     }
 773   }
 774   return false;
 775 }
 776 
 777 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
 778   active_handles()->oops_do(f);
 779   // Do oop for ThreadShadow
 780   f->do_oop((oop*)&_pending_exception);
 781   handle_area()->oops_do(f);
 782 }
 783 
 784 void Thread::nmethods_do(CodeBlobClosure* cf) {
 785   // no nmethods in a generic thread...
 786 }
 787 
 788 void Thread::metadata_handles_do(void f(Metadata*)) {
 789   // Only walk the Handles in Thread.
 790   if (metadata_handles() != NULL) {
 791     for (int i = 0; i< metadata_handles()->length(); i++) {
 792       f(metadata_handles()->at(i));
 793     }
 794   }
 795 }
 796 
 797 void Thread::print_on(outputStream* st) const {
 798   // get_priority assumes osthread initialized
 799   if (osthread() != NULL) {
 800     int os_prio;
 801     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 802       st->print("os_prio=%d ", os_prio);
 803     }
 804     st->print("tid=" INTPTR_FORMAT " ", this);
 805     ext().print_on(st);
 806     osthread()->print_on(st);
 807   }
 808   debug_only(if (WizardMode) print_owned_locks_on(st);)
 809 }
 810 
 811 // Thread::print_on_error() is called by fatal error handler. Don't use
 812 // any lock or allocate memory.
 813 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 814   if (is_VM_thread())                 st->print("VMThread");
 815   else if (is_Compiler_thread())      st->print("CompilerThread");
 816   else if (is_Java_thread())          st->print("JavaThread");
 817   else if (is_GC_task_thread())       st->print("GCTaskThread");
 818   else if (is_Watcher_thread())       st->print("WatcherThread");
 819   else if (is_ConcurrentGC_thread())  st->print("ConcurrentGCThread");
 820   else                                st->print("Thread");
 821 
 822   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 823             _stack_base - _stack_size, _stack_base);
 824 
 825   if (osthread()) {
 826     st->print(" [id=%d]", osthread()->thread_id());
 827   }
 828 }
 829 
 830 #ifdef ASSERT
 831 void Thread::print_owned_locks_on(outputStream* st) const {
 832   Monitor *cur = _owned_locks;
 833   if (cur == NULL) {
 834     st->print(" (no locks) ");
 835   } else {
 836     st->print_cr(" Locks owned:");
 837     while (cur) {
 838       cur->print_on(st);
 839       cur = cur->next();
 840     }
 841   }
 842 }
 843 
 844 static int ref_use_count  = 0;
 845 
 846 bool Thread::owns_locks_but_compiled_lock() const {
 847   for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 848     if (cur != Compile_lock) return true;
 849   }
 850   return false;
 851 }
 852 
 853 
 854 #endif
 855 
 856 #ifndef PRODUCT
 857 
 858 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
 859 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
 860 // no threads which allow_vm_block's are held
 861 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 862   // Check if current thread is allowed to block at a safepoint
 863   if (!(_allow_safepoint_count == 0)) {
 864     fatal("Possible safepoint reached by thread that does not allow it");
 865   }
 866   if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 867     fatal("LEAF method calling lock?");
 868   }
 869 
 870 #ifdef ASSERT
 871   if (potential_vm_operation && is_Java_thread()
 872       && !Universe::is_bootstrapping()) {
 873     // Make sure we do not hold any locks that the VM thread also uses.
 874     // This could potentially lead to deadlocks
 875     for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 876       // Threads_lock is special, since the safepoint synchronization will not start before this is
 877       // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 878       // since it is used to transfer control between JavaThreads and the VMThread
 879       // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
 880       if ((cur->allow_vm_block() &&
 881            cur != Threads_lock &&
 882            cur != Compile_lock &&               // Temporary: should not be necessary when we get separate compilation
 883            cur != VMOperationRequest_lock &&
 884            cur != VMOperationQueue_lock) ||
 885            cur->rank() == Mutex::special) {
 886         fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
 887       }
 888     }
 889   }
 890 
 891   if (GCALotAtAllSafepoints) {
 892     // We could enter a safepoint here and thus have a gc
 893     InterfaceSupport::check_gc_alot();
 894   }
 895 #endif
 896 }
 897 #endif
 898 
 899 bool Thread::is_in_stack(address adr) const {
 900   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
 901   address end = os::current_stack_pointer();
 902   // Allow non Java threads to call this without stack_base
 903   if (_stack_base == NULL) return true;
 904   if (stack_base() >= adr && adr >= end) return true;
 905 
 906   return false;
 907 }
 908 
 909 
 910 bool Thread::is_in_usable_stack(address adr) const {
 911   size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
 912   size_t usable_stack_size = _stack_size - stack_guard_size;
 913 
 914   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
 915 }
 916 
 917 
 918 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
 919 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
 920 // used for compilation in the future. If that change is made, the need for these methods
 921 // should be revisited, and they should be removed if possible.
 922 
 923 bool Thread::is_lock_owned(address adr) const {
 924   return on_local_stack(adr);
 925 }
 926 
 927 bool Thread::set_as_starting_thread() {
 928   // NOTE: this must be called inside the main thread.
 929   return os::create_main_thread((JavaThread*)this);
 930 }
 931 
 932 static void initialize_class(Symbol* class_name, TRAPS) {
 933   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
 934   InstanceKlass::cast(klass)->initialize(CHECK);
 935 }
 936 
 937 
 938 // Creates the initial ThreadGroup
 939 static Handle create_initial_thread_group(TRAPS) {
 940   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
 941   instanceKlassHandle klass (THREAD, k);
 942 
 943   Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
 944   {
 945     JavaValue result(T_VOID);
 946     JavaCalls::call_special(&result,
 947                             system_instance,
 948                             klass,
 949                             vmSymbols::object_initializer_name(),
 950                             vmSymbols::void_method_signature(),
 951                             CHECK_NH);
 952   }
 953   Universe::set_system_thread_group(system_instance());
 954 
 955   Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
 956   {
 957     JavaValue result(T_VOID);
 958     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
 959     JavaCalls::call_special(&result,
 960                             main_instance,
 961                             klass,
 962                             vmSymbols::object_initializer_name(),
 963                             vmSymbols::threadgroup_string_void_signature(),
 964                             system_instance,
 965                             string,
 966                             CHECK_NH);
 967   }
 968   return main_instance;
 969 }
 970 
 971 // Creates the initial Thread
 972 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
 973                                  TRAPS) {
 974   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
 975   instanceKlassHandle klass (THREAD, k);
 976   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
 977 
 978   java_lang_Thread::set_thread(thread_oop(), thread);
 979   java_lang_Thread::set_priority(thread_oop(), NormPriority);
 980   thread->set_threadObj(thread_oop());
 981 
 982   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
 983 
 984   JavaValue result(T_VOID);
 985   JavaCalls::call_special(&result, thread_oop,
 986                           klass,
 987                           vmSymbols::object_initializer_name(),
 988                           vmSymbols::threadgroup_string_void_signature(),
 989                           thread_group,
 990                           string,
 991                           CHECK_NULL);
 992   return thread_oop();
 993 }
 994 
 995 static void call_initializeSystemClass(TRAPS) {
 996   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
 997   instanceKlassHandle klass (THREAD, k);
 998 
 999   JavaValue result(T_VOID);
1000   JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1001                          vmSymbols::void_method_signature(), CHECK);
1002 }
1003 
1004 char java_runtime_name[128] = "";
1005 char java_runtime_version[128] = "";
1006 
1007 // extract the JRE name from sun.misc.Version.java_runtime_name
1008 static const char* get_java_runtime_name(TRAPS) {
1009   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1010                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1011   fieldDescriptor fd;
1012   bool found = k != NULL &&
1013                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1014                                                         vmSymbols::string_signature(), &fd);
1015   if (found) {
1016     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1017     if (name_oop == NULL) {
1018       return NULL;
1019     }
1020     const char* name = java_lang_String::as_utf8_string(name_oop,
1021                                                         java_runtime_name,
1022                                                         sizeof(java_runtime_name));
1023     return name;
1024   } else {
1025     return NULL;
1026   }
1027 }
1028 
1029 // extract the JRE version from sun.misc.Version.java_runtime_version
1030 static const char* get_java_runtime_version(TRAPS) {
1031   Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1032                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1033   fieldDescriptor fd;
1034   bool found = k != NULL &&
1035                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1036                                                         vmSymbols::string_signature(), &fd);
1037   if (found) {
1038     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1039     if (name_oop == NULL) {
1040       return NULL;
1041     }
1042     const char* name = java_lang_String::as_utf8_string(name_oop,
1043                                                         java_runtime_version,
1044                                                         sizeof(java_runtime_version));
1045     return name;
1046   } else {
1047     return NULL;
1048   }
1049 }
1050 
1051 // General purpose hook into Java code, run once when the VM is initialized.
1052 // The Java library method itself may be changed independently from the VM.
1053 static void call_postVMInitHook(TRAPS) {
1054   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1055   instanceKlassHandle klass (THREAD, k);
1056   if (klass.not_null()) {
1057     JavaValue result(T_VOID);
1058     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1059                            vmSymbols::void_method_signature(),
1060                            CHECK);
1061   }
1062 }
1063 
1064 static void reset_vm_info_property(TRAPS) {
1065   // the vm info string
1066   ResourceMark rm(THREAD);
1067   const char *vm_info = VM_Version::vm_info_string();
1068 
1069   // java.lang.System class
1070   Klass* k =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1071   instanceKlassHandle klass (THREAD, k);
1072 
1073   // setProperty arguments
1074   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1075   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1076 
1077   // return value
1078   JavaValue r(T_OBJECT);
1079 
1080   // public static String setProperty(String key, String value);
1081   JavaCalls::call_static(&r,
1082                          klass,
1083                          vmSymbols::setProperty_name(),
1084                          vmSymbols::string_string_string_signature(),
1085                          key_str,
1086                          value_str,
1087                          CHECK);
1088 }
1089 
1090 
1091 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1092                                     bool daemon, TRAPS) {
1093   assert(thread_group.not_null(), "thread group should be specified");
1094   assert(threadObj() == NULL, "should only create Java thread object once");
1095 
1096   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1097   instanceKlassHandle klass (THREAD, k);
1098   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1099 
1100   java_lang_Thread::set_thread(thread_oop(), this);
1101   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1102   set_threadObj(thread_oop());
1103 
1104   JavaValue result(T_VOID);
1105   if (thread_name != NULL) {
1106     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1107     // Thread gets assigned specified name and null target
1108     JavaCalls::call_special(&result,
1109                             thread_oop,
1110                             klass,
1111                             vmSymbols::object_initializer_name(),
1112                             vmSymbols::threadgroup_string_void_signature(),
1113                             thread_group, // Argument 1
1114                             name,         // Argument 2
1115                             THREAD);
1116   } else {
1117     // Thread gets assigned name "Thread-nnn" and null target
1118     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1119     JavaCalls::call_special(&result,
1120                             thread_oop,
1121                             klass,
1122                             vmSymbols::object_initializer_name(),
1123                             vmSymbols::threadgroup_runnable_void_signature(),
1124                             thread_group, // Argument 1
1125                             Handle(),     // Argument 2
1126                             THREAD);
1127   }
1128 
1129 
1130   if (daemon) {
1131     java_lang_Thread::set_daemon(thread_oop());
1132   }
1133 
1134   if (HAS_PENDING_EXCEPTION) {
1135     return;
1136   }
1137 
1138   KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1139   Handle threadObj(THREAD, this->threadObj());
1140 
1141   JavaCalls::call_special(&result,
1142                           thread_group,
1143                           group,
1144                           vmSymbols::add_method_name(),
1145                           vmSymbols::thread_void_signature(),
1146                           threadObj,          // Arg 1
1147                           THREAD);
1148 }
1149 
1150 // NamedThread --  non-JavaThread subclasses with multiple
1151 // uniquely named instances should derive from this.
1152 NamedThread::NamedThread() : Thread() {
1153   _name = NULL;
1154   _processed_thread = NULL;
1155 }
1156 
1157 NamedThread::~NamedThread() {
1158   if (_name != NULL) {
1159     FREE_C_HEAP_ARRAY(char, _name);
1160     _name = NULL;
1161   }
1162 }
1163 
1164 void NamedThread::set_name(const char* format, ...) {
1165   guarantee(_name == NULL, "Only get to set name once.");
1166   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1167   guarantee(_name != NULL, "alloc failure");
1168   va_list ap;
1169   va_start(ap, format);
1170   jio_vsnprintf(_name, max_name_len, format, ap);
1171   va_end(ap);
1172 }
1173 
1174 void NamedThread::initialize_named_thread() {
1175   set_native_thread_name(name());
1176 }
1177 
1178 void NamedThread::print_on(outputStream* st) const {
1179   st->print("\"%s\" ", name());
1180   Thread::print_on(st);
1181   st->cr();
1182 }
1183 
1184 
1185 // ======= WatcherThread ========
1186 
1187 // The watcher thread exists to simulate timer interrupts.  It should
1188 // be replaced by an abstraction over whatever native support for
1189 // timer interrupts exists on the platform.
1190 
1191 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1192 bool WatcherThread::_startable = false;
1193 volatile bool  WatcherThread::_should_terminate = false;
1194 
1195 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1196   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1197   if (os::create_thread(this, os::watcher_thread)) {
1198     _watcher_thread = this;
1199 
1200     // Set the watcher thread to the highest OS priority which should not be
1201     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1202     // is created. The only normal thread using this priority is the reference
1203     // handler thread, which runs for very short intervals only.
1204     // If the VMThread's priority is not lower than the WatcherThread profiling
1205     // will be inaccurate.
1206     os::set_priority(this, MaxPriority);
1207     if (!DisableStartThread) {
1208       os::start_thread(this);
1209     }
1210   }
1211 }
1212 
1213 int WatcherThread::sleep() const {
1214   // The WatcherThread does not participate in the safepoint protocol
1215   // for the PeriodicTask_lock because it is not a JavaThread.
1216   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1217 
1218   if (_should_terminate) {
1219     // check for termination before we do any housekeeping or wait
1220     return 0;  // we did not sleep.
1221   }
1222 
1223   // remaining will be zero if there are no tasks,
1224   // causing the WatcherThread to sleep until a task is
1225   // enrolled
1226   int remaining = PeriodicTask::time_to_wait();
1227   int time_slept = 0;
1228 
1229   // we expect this to timeout - we only ever get unparked when
1230   // we should terminate or when a new task has been enrolled
1231   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1232 
1233   jlong time_before_loop = os::javaTimeNanos();
1234 
1235   while (true) {
1236     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1237                                             remaining);
1238     jlong now = os::javaTimeNanos();
1239 
1240     if (remaining == 0) {
1241       // if we didn't have any tasks we could have waited for a long time
1242       // consider the time_slept zero and reset time_before_loop
1243       time_slept = 0;
1244       time_before_loop = now;
1245     } else {
1246       // need to recalculate since we might have new tasks in _tasks
1247       time_slept = (int) ((now - time_before_loop) / 1000000);
1248     }
1249 
1250     // Change to task list or spurious wakeup of some kind
1251     if (timedout || _should_terminate) {
1252       break;
1253     }
1254 
1255     remaining = PeriodicTask::time_to_wait();
1256     if (remaining == 0) {
1257       // Last task was just disenrolled so loop around and wait until
1258       // another task gets enrolled
1259       continue;
1260     }
1261 
1262     remaining -= time_slept;
1263     if (remaining <= 0) {
1264       break;
1265     }
1266   }
1267 
1268   return time_slept;
1269 }
1270 
1271 void WatcherThread::run() {
1272   assert(this == watcher_thread(), "just checking");
1273 
1274   this->record_stack_base_and_size();
1275   this->initialize_thread_local_storage();
1276   this->set_native_thread_name(this->name());
1277   this->set_active_handles(JNIHandleBlock::allocate_block());
1278   while (true) {
1279     assert(watcher_thread() == Thread::current(), "thread consistency check");
1280     assert(watcher_thread() == this, "thread consistency check");
1281 
1282     // Calculate how long it'll be until the next PeriodicTask work
1283     // should be done, and sleep that amount of time.
1284     int time_waited = sleep();
1285 
1286     if (is_error_reported()) {
1287       // A fatal error has happened, the error handler(VMError::report_and_die)
1288       // should abort JVM after creating an error log file. However in some
1289       // rare cases, the error handler itself might deadlock. Here we try to
1290       // kill JVM if the fatal error handler fails to abort in 2 minutes.
1291       //
1292       // This code is in WatcherThread because WatcherThread wakes up
1293       // periodically so the fatal error handler doesn't need to do anything;
1294       // also because the WatcherThread is less likely to crash than other
1295       // threads.
1296 
1297       for (;;) {
1298         if (!ShowMessageBoxOnError
1299             && (OnError == NULL || OnError[0] == '\0')
1300             && Arguments::abort_hook() == NULL) {
1301           os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1302           fdStream err(defaultStream::output_fd());
1303           err.print_raw_cr("# [ timer expired, abort... ]");
1304           // skip atexit/vm_exit/vm_abort hooks
1305           os::die();
1306         }
1307 
1308         // Wake up 5 seconds later, the fatal handler may reset OnError or
1309         // ShowMessageBoxOnError when it is ready to abort.
1310         os::sleep(this, 5 * 1000, false);
1311       }
1312     }
1313 
1314     if (_should_terminate) {
1315       // check for termination before posting the next tick
1316       break;
1317     }
1318 
1319     PeriodicTask::real_time_tick(time_waited);
1320   }
1321 
1322   // Signal that it is terminated
1323   {
1324     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1325     _watcher_thread = NULL;
1326     Terminator_lock->notify();
1327   }
1328 
1329   // Thread destructor usually does this..
1330   ThreadLocalStorage::set_thread(NULL);
1331 }
1332 
1333 void WatcherThread::start() {
1334   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1335 
1336   if (watcher_thread() == NULL && _startable) {
1337     _should_terminate = false;
1338     // Create the single instance of WatcherThread
1339     new WatcherThread();
1340   }
1341 }
1342 
1343 void WatcherThread::make_startable() {
1344   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1345   _startable = true;
1346 }
1347 
1348 void WatcherThread::stop() {
1349   {
1350     // Follow normal safepoint aware lock enter protocol since the
1351     // WatcherThread is stopped by another JavaThread.
1352     MutexLocker ml(PeriodicTask_lock);
1353     _should_terminate = true;
1354 
1355     WatcherThread* watcher = watcher_thread();
1356     if (watcher != NULL) {
1357       // unpark the WatcherThread so it can see that it should terminate
1358       watcher->unpark();
1359     }
1360   }
1361 
1362   MutexLocker mu(Terminator_lock);
1363 
1364   while (watcher_thread() != NULL) {
1365     // This wait should make safepoint checks, wait without a timeout,
1366     // and wait as a suspend-equivalent condition.
1367     //
1368     // Note: If the FlatProfiler is running, then this thread is waiting
1369     // for the WatcherThread to terminate and the WatcherThread, via the
1370     // FlatProfiler task, is waiting for the external suspend request on
1371     // this thread to complete. wait_for_ext_suspend_completion() will
1372     // eventually timeout, but that takes time. Making this wait a
1373     // suspend-equivalent condition solves that timeout problem.
1374     //
1375     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1376                           Mutex::_as_suspend_equivalent_flag);
1377   }
1378 }
1379 
1380 void WatcherThread::unpark() {
1381   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1382   PeriodicTask_lock->notify();
1383 }
1384 
1385 void WatcherThread::print_on(outputStream* st) const {
1386   st->print("\"%s\" ", name());
1387   Thread::print_on(st);
1388   st->cr();
1389 }
1390 
1391 // ======= JavaThread ========
1392 
1393 #if INCLUDE_JVMCI
1394 
1395 jlong* JavaThread::_jvmci_old_thread_counters;
1396 
1397 bool jvmci_counters_include(JavaThread* thread) {
1398   oop threadObj = thread->threadObj();
1399   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1400 }
1401 
1402 void JavaThread::collect_counters(typeArrayOop array) {
1403   if (JVMCICounterSize > 0) {
1404     MutexLocker tl(Threads_lock);
1405     for (int i = 0; i < array->length(); i++) {
1406       array->long_at_put(i, _jvmci_old_thread_counters[i]);
1407     }
1408     for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1409       if (jvmci_counters_include(tp)) {
1410         for (int i = 0; i < array->length(); i++) {
1411           array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1412         }
1413       }
1414     }
1415   }
1416 }
1417 
1418 #endif // INCLUDE_JVMCI
1419 
1420 // A JavaThread is a normal Java thread
1421 
1422 void JavaThread::initialize() {
1423   // Initialize fields
1424 
1425   // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1426   set_claimed_par_id(UINT_MAX);
1427 
1428   set_saved_exception_pc(NULL);
1429   set_threadObj(NULL);
1430   _anchor.clear();
1431   set_entry_point(NULL);
1432   set_jni_functions(jni_functions());
1433   set_callee_target(NULL);
1434   set_vm_result(NULL);
1435   set_vm_result_2(NULL);
1436   set_vframe_array_head(NULL);
1437   set_vframe_array_last(NULL);
1438   set_deferred_locals(NULL);
1439   set_deopt_mark(NULL);
1440   set_deopt_nmethod(NULL);
1441   clear_must_deopt_id();
1442   set_monitor_chunks(NULL);
1443   set_next(NULL);
1444   set_thread_state(_thread_new);
1445   _terminated = _not_terminated;
1446   _privileged_stack_top = NULL;
1447   _array_for_gc = NULL;
1448   _suspend_equivalent = false;
1449   _in_deopt_handler = 0;
1450   _doing_unsafe_access = false;
1451   _stack_guard_state = stack_guard_unused;
1452 #if INCLUDE_JVMCI
1453   _pending_monitorenter = false;
1454   _pending_deoptimization = -1;
1455   _pending_failed_speculation = NULL;
1456   _pending_transfer_to_interpreter = false;
1457   _jvmci._alternate_call_target = NULL;
1458   assert(_jvmci._implicit_exception_pc == NULL, "must be");
1459   if (JVMCICounterSize > 0) {
1460     _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1461     memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1462   } else {
1463     _jvmci_counters = NULL;
1464   }
1465 #endif // INCLUDE_JVMCI
1466   (void)const_cast<oop&>(_exception_oop = oop(NULL));
1467   _exception_pc  = 0;
1468   _exception_handler_pc = 0;
1469   _is_method_handle_return = 0;
1470   _jvmti_thread_state= NULL;
1471   _should_post_on_exceptions_flag = JNI_FALSE;
1472   _jvmti_get_loaded_classes_closure = NULL;
1473   _interp_only_mode    = 0;
1474   _special_runtime_exit_condition = _no_async_condition;
1475   _pending_async_exception = NULL;
1476   _thread_stat = NULL;
1477   _thread_stat = new ThreadStatistics();
1478   _blocked_on_compilation = false;
1479   _jni_active_critical = 0;
1480   _pending_jni_exception_check_fn = NULL;
1481   _do_not_unlock_if_synchronized = false;
1482   _cached_monitor_info = NULL;
1483   _parker = Parker::Allocate(this);
1484 
1485 #ifndef PRODUCT
1486   _jmp_ring_index = 0;
1487   for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1488     record_jump(NULL, NULL, NULL, 0);
1489   }
1490 #endif // PRODUCT
1491 
1492   set_thread_profiler(NULL);
1493   if (FlatProfiler::is_active()) {
1494     // This is where we would decide to either give each thread it's own profiler
1495     // or use one global one from FlatProfiler,
1496     // or up to some count of the number of profiled threads, etc.
1497     ThreadProfiler* pp = new ThreadProfiler();
1498     pp->engage();
1499     set_thread_profiler(pp);
1500   }
1501 
1502   // Setup safepoint state info for this thread
1503   ThreadSafepointState::create(this);
1504 
1505   debug_only(_java_call_counter = 0);
1506 
1507   // JVMTI PopFrame support
1508   _popframe_condition = popframe_inactive;
1509   _popframe_preserved_args = NULL;
1510   _popframe_preserved_args_size = 0;
1511   _frames_to_pop_failed_realloc = 0;
1512 
1513   pd_initialize();
1514 }
1515 
1516 #if INCLUDE_ALL_GCS
1517 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1518 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1519 #endif // INCLUDE_ALL_GCS
1520 
1521 JavaThread::JavaThread(bool is_attaching_via_jni) :
1522                        Thread()
1523 #if INCLUDE_ALL_GCS
1524                        , _satb_mark_queue(&_satb_mark_queue_set),
1525                        _dirty_card_queue(&_dirty_card_queue_set)
1526 #endif // INCLUDE_ALL_GCS
1527 {
1528   initialize();
1529   if (is_attaching_via_jni) {
1530     _jni_attach_state = _attaching_via_jni;
1531   } else {
1532     _jni_attach_state = _not_attaching_via_jni;
1533   }
1534   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1535 }
1536 
1537 bool JavaThread::reguard_stack(address cur_sp) {
1538   if (_stack_guard_state != stack_guard_yellow_disabled) {
1539     return true; // Stack already guarded or guard pages not needed.
1540   }
1541 
1542   if (register_stack_overflow()) {
1543     // For those architectures which have separate register and
1544     // memory stacks, we must check the register stack to see if
1545     // it has overflowed.
1546     return false;
1547   }
1548 
1549   // Java code never executes within the yellow zone: the latter is only
1550   // there to provoke an exception during stack banging.  If java code
1551   // is executing there, either StackShadowPages should be larger, or
1552   // some exception code in c1, c2 or the interpreter isn't unwinding
1553   // when it should.
1554   guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1555 
1556   enable_stack_yellow_zone();
1557   return true;
1558 }
1559 
1560 bool JavaThread::reguard_stack(void) {
1561   return reguard_stack(os::current_stack_pointer());
1562 }
1563 
1564 
1565 void JavaThread::block_if_vm_exited() {
1566   if (_terminated == _vm_exited) {
1567     // _vm_exited is set at safepoint, and Threads_lock is never released
1568     // we will block here forever
1569     Threads_lock->lock_without_safepoint_check();
1570     ShouldNotReachHere();
1571   }
1572 }
1573 
1574 
1575 // Remove this ifdef when C1 is ported to the compiler interface.
1576 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1577 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1578 
1579 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1580                        Thread()
1581 #if INCLUDE_ALL_GCS
1582                        , _satb_mark_queue(&_satb_mark_queue_set),
1583                        _dirty_card_queue(&_dirty_card_queue_set)
1584 #endif // INCLUDE_ALL_GCS
1585 {
1586   initialize();
1587   _jni_attach_state = _not_attaching_via_jni;
1588   set_entry_point(entry_point);
1589   // Create the native thread itself.
1590   // %note runtime_23
1591   os::ThreadType thr_type = os::java_thread;
1592   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1593                                                      os::java_thread;
1594   os::create_thread(this, thr_type, stack_sz);
1595   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1596   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1597   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1598   // the exception consists of creating the exception object & initializing it, initialization
1599   // will leave the VM via a JavaCall and then all locks must be unlocked).
1600   //
1601   // The thread is still suspended when we reach here. Thread must be explicit started
1602   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1603   // by calling Threads:add. The reason why this is not done here, is because the thread
1604   // object must be fully initialized (take a look at JVM_Start)
1605 }
1606 
1607 JavaThread::~JavaThread() {
1608 
1609   // JSR166 -- return the parker to the free list
1610   Parker::Release(_parker);
1611   _parker = NULL;
1612 
1613   // Free any remaining  previous UnrollBlock
1614   vframeArray* old_array = vframe_array_last();
1615 
1616   if (old_array != NULL) {
1617     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1618     old_array->set_unroll_block(NULL);
1619     delete old_info;
1620     delete old_array;
1621   }
1622 
1623   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1624   if (deferred != NULL) {
1625     // This can only happen if thread is destroyed before deoptimization occurs.
1626     assert(deferred->length() != 0, "empty array!");
1627     do {
1628       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1629       deferred->remove_at(0);
1630       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1631       delete dlv;
1632     } while (deferred->length() != 0);
1633     delete deferred;
1634   }
1635 
1636   // All Java related clean up happens in exit
1637   ThreadSafepointState::destroy(this);
1638   if (_thread_profiler != NULL) delete _thread_profiler;
1639   if (_thread_stat != NULL) delete _thread_stat;
1640 
1641 #if INCLUDE_JVMCI
1642   if (JVMCICounterSize > 0) {
1643     if (jvmci_counters_include(this)) {
1644       for (int i = 0; i < JVMCICounterSize; i++) {
1645         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1646       }
1647     }
1648     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1649   }
1650 #endif // INCLUDE_JVMCI
1651 }
1652 
1653 
1654 // The first routine called by a new Java thread
1655 void JavaThread::run() {
1656   // initialize thread-local alloc buffer related fields
1657   this->initialize_tlab();
1658 
1659   // used to test validity of stack trace backs
1660   this->record_base_of_stack_pointer();
1661 
1662   // Record real stack base and size.
1663   this->record_stack_base_and_size();
1664 
1665   // Initialize thread local storage; set before calling MutexLocker
1666   this->initialize_thread_local_storage();
1667 
1668   this->create_stack_guard_pages();
1669 
1670   this->cache_global_variables();
1671 
1672   // Thread is now sufficient initialized to be handled by the safepoint code as being
1673   // in the VM. Change thread state from _thread_new to _thread_in_vm
1674   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1675 
1676   assert(JavaThread::current() == this, "sanity check");
1677   assert(!Thread::current()->owns_locks(), "sanity check");
1678 
1679   DTRACE_THREAD_PROBE(start, this);
1680 
1681   // This operation might block. We call that after all safepoint checks for a new thread has
1682   // been completed.
1683   this->set_active_handles(JNIHandleBlock::allocate_block());
1684 
1685   if (JvmtiExport::should_post_thread_life()) {
1686     JvmtiExport::post_thread_start(this);
1687   }
1688 
1689   EventThreadStart event;
1690   if (event.should_commit()) {
1691     event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1692     event.commit();
1693   }
1694 
1695   // We call another function to do the rest so we are sure that the stack addresses used
1696   // from there will be lower than the stack base just computed
1697   thread_main_inner();
1698 
1699   // Note, thread is no longer valid at this point!
1700 }
1701 
1702 
1703 void JavaThread::thread_main_inner() {
1704   assert(JavaThread::current() == this, "sanity check");
1705   assert(this->threadObj() != NULL, "just checking");
1706 
1707   // Execute thread entry point unless this thread has a pending exception
1708   // or has been stopped before starting.
1709   // Note: Due to JVM_StopThread we can have pending exceptions already!
1710   if (!this->has_pending_exception() &&
1711       !java_lang_Thread::is_stillborn(this->threadObj())) {
1712     {
1713       ResourceMark rm(this);
1714       this->set_native_thread_name(this->get_thread_name());
1715     }
1716     HandleMark hm(this);
1717     this->entry_point()(this, this);
1718   }
1719 
1720   DTRACE_THREAD_PROBE(stop, this);
1721 
1722   this->exit(false);
1723   delete this;
1724 }
1725 
1726 
1727 static void ensure_join(JavaThread* thread) {
1728   // We do not need to grap the Threads_lock, since we are operating on ourself.
1729   Handle threadObj(thread, thread->threadObj());
1730   assert(threadObj.not_null(), "java thread object must exist");
1731   ObjectLocker lock(threadObj, thread);
1732   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1733   thread->clear_pending_exception();
1734   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1735   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1736   // Clear the native thread instance - this makes isAlive return false and allows the join()
1737   // to complete once we've done the notify_all below
1738   java_lang_Thread::set_thread(threadObj(), NULL);
1739   lock.notify_all(thread);
1740   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1741   thread->clear_pending_exception();
1742 }
1743 
1744 
1745 // For any new cleanup additions, please check to see if they need to be applied to
1746 // cleanup_failed_attach_current_thread as well.
1747 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1748   assert(this == JavaThread::current(), "thread consistency check");
1749 
1750   HandleMark hm(this);
1751   Handle uncaught_exception(this, this->pending_exception());
1752   this->clear_pending_exception();
1753   Handle threadObj(this, this->threadObj());
1754   assert(threadObj.not_null(), "Java thread object should be created");
1755 
1756   if (get_thread_profiler() != NULL) {
1757     get_thread_profiler()->disengage();
1758     ResourceMark rm;
1759     get_thread_profiler()->print(get_thread_name());
1760   }
1761 
1762 
1763   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1764   {
1765     EXCEPTION_MARK;
1766 
1767     CLEAR_PENDING_EXCEPTION;
1768   }
1769   if (!destroy_vm) {
1770     if (uncaught_exception.not_null()) {
1771       EXCEPTION_MARK;
1772       // Call method Thread.dispatchUncaughtException().
1773       KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1774       JavaValue result(T_VOID);
1775       JavaCalls::call_virtual(&result,
1776                               threadObj, thread_klass,
1777                               vmSymbols::dispatchUncaughtException_name(),
1778                               vmSymbols::throwable_void_signature(),
1779                               uncaught_exception,
1780                               THREAD);
1781       if (HAS_PENDING_EXCEPTION) {
1782         ResourceMark rm(this);
1783         jio_fprintf(defaultStream::error_stream(),
1784                     "\nException: %s thrown from the UncaughtExceptionHandler"
1785                     " in thread \"%s\"\n",
1786                     pending_exception()->klass()->external_name(),
1787                     get_thread_name());
1788         CLEAR_PENDING_EXCEPTION;
1789       }
1790     }
1791 
1792     // Called before the java thread exit since we want to read info
1793     // from java_lang_Thread object
1794     EventThreadEnd event;
1795     if (event.should_commit()) {
1796       event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1797       event.commit();
1798     }
1799 
1800     // Call after last event on thread
1801     EVENT_THREAD_EXIT(this);
1802 
1803     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1804     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1805     // is deprecated anyhow.
1806     if (!is_Compiler_thread()) {
1807       int count = 3;
1808       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1809         EXCEPTION_MARK;
1810         JavaValue result(T_VOID);
1811         KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1812         JavaCalls::call_virtual(&result,
1813                                 threadObj, thread_klass,
1814                                 vmSymbols::exit_method_name(),
1815                                 vmSymbols::void_method_signature(),
1816                                 THREAD);
1817         CLEAR_PENDING_EXCEPTION;
1818       }
1819     }
1820     // notify JVMTI
1821     if (JvmtiExport::should_post_thread_life()) {
1822       JvmtiExport::post_thread_end(this);
1823     }
1824 
1825     // We have notified the agents that we are exiting, before we go on,
1826     // we must check for a pending external suspend request and honor it
1827     // in order to not surprise the thread that made the suspend request.
1828     while (true) {
1829       {
1830         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1831         if (!is_external_suspend()) {
1832           set_terminated(_thread_exiting);
1833           ThreadService::current_thread_exiting(this);
1834           break;
1835         }
1836         // Implied else:
1837         // Things get a little tricky here. We have a pending external
1838         // suspend request, but we are holding the SR_lock so we
1839         // can't just self-suspend. So we temporarily drop the lock
1840         // and then self-suspend.
1841       }
1842 
1843       ThreadBlockInVM tbivm(this);
1844       java_suspend_self();
1845 
1846       // We're done with this suspend request, but we have to loop around
1847       // and check again. Eventually we will get SR_lock without a pending
1848       // external suspend request and will be able to mark ourselves as
1849       // exiting.
1850     }
1851     // no more external suspends are allowed at this point
1852   } else {
1853     // before_exit() has already posted JVMTI THREAD_END events
1854   }
1855 
1856   // Notify waiters on thread object. This has to be done after exit() is called
1857   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1858   // group should have the destroyed bit set before waiters are notified).
1859   ensure_join(this);
1860   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1861 
1862   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1863   // held by this thread must be released. The spec does not distinguish
1864   // between JNI-acquired and regular Java monitors. We can only see
1865   // regular Java monitors here if monitor enter-exit matching is broken.
1866   //
1867   // Optionally release any monitors for regular JavaThread exits. This
1868   // is provided as a work around for any bugs in monitor enter-exit
1869   // matching. This can be expensive so it is not enabled by default.
1870   // ObjectMonitor::Knob_ExitRelease is a superset of the
1871   // JNIDetachReleasesMonitors option.
1872   //
1873   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1874   // ObjectSynchronizer::release_monitors_owned_by_thread().
1875   if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1876       ObjectMonitor::Knob_ExitRelease) {
1877     // Sanity check even though JNI DetachCurrentThread() would have
1878     // returned JNI_ERR if there was a Java frame. JavaThread exit
1879     // should be done executing Java code by the time we get here.
1880     assert(!this->has_last_Java_frame(),
1881            "should not have a Java frame when detaching or exiting");
1882     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1883     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1884   }
1885 
1886   // These things needs to be done while we are still a Java Thread. Make sure that thread
1887   // is in a consistent state, in case GC happens
1888   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1889 
1890   if (active_handles() != NULL) {
1891     JNIHandleBlock* block = active_handles();
1892     set_active_handles(NULL);
1893     JNIHandleBlock::release_block(block);
1894   }
1895 
1896   if (free_handle_block() != NULL) {
1897     JNIHandleBlock* block = free_handle_block();
1898     set_free_handle_block(NULL);
1899     JNIHandleBlock::release_block(block);
1900   }
1901 
1902   // These have to be removed while this is still a valid thread.
1903   remove_stack_guard_pages();
1904 
1905   if (UseTLAB) {
1906     tlab().make_parsable(true);  // retire TLAB
1907   }
1908 
1909   if (JvmtiEnv::environments_might_exist()) {
1910     JvmtiExport::cleanup_thread(this);
1911   }
1912 
1913   // We must flush any deferred card marks before removing a thread from
1914   // the list of active threads.
1915   Universe::heap()->flush_deferred_store_barrier(this);
1916   assert(deferred_card_mark().is_empty(), "Should have been flushed");
1917 
1918 #if INCLUDE_ALL_GCS
1919   // We must flush the G1-related buffers before removing a thread
1920   // from the list of active threads. We must do this after any deferred
1921   // card marks have been flushed (above) so that any entries that are
1922   // added to the thread's dirty card queue as a result are not lost.
1923   if (UseG1GC) {
1924     flush_barrier_queues();
1925   }
1926 #endif // INCLUDE_ALL_GCS
1927 
1928   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1929   Threads::remove(this);
1930 }
1931 
1932 #if INCLUDE_ALL_GCS
1933 // Flush G1-related queues.
1934 void JavaThread::flush_barrier_queues() {
1935   satb_mark_queue().flush();
1936   dirty_card_queue().flush();
1937 }
1938 
1939 void JavaThread::initialize_queues() {
1940   assert(!SafepointSynchronize::is_at_safepoint(),
1941          "we should not be at a safepoint");
1942 
1943   ObjPtrQueue& satb_queue = satb_mark_queue();
1944   SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1945   // The SATB queue should have been constructed with its active
1946   // field set to false.
1947   assert(!satb_queue.is_active(), "SATB queue should not be active");
1948   assert(satb_queue.is_empty(), "SATB queue should be empty");
1949   // If we are creating the thread during a marking cycle, we should
1950   // set the active field of the SATB queue to true.
1951   if (satb_queue_set.is_active()) {
1952     satb_queue.set_active(true);
1953   }
1954 
1955   DirtyCardQueue& dirty_queue = dirty_card_queue();
1956   // The dirty card queue should have been constructed with its
1957   // active field set to true.
1958   assert(dirty_queue.is_active(), "dirty card queue should be active");
1959 }
1960 #endif // INCLUDE_ALL_GCS
1961 
1962 void JavaThread::cleanup_failed_attach_current_thread() {
1963   if (get_thread_profiler() != NULL) {
1964     get_thread_profiler()->disengage();
1965     ResourceMark rm;
1966     get_thread_profiler()->print(get_thread_name());
1967   }
1968 
1969   if (active_handles() != NULL) {
1970     JNIHandleBlock* block = active_handles();
1971     set_active_handles(NULL);
1972     JNIHandleBlock::release_block(block);
1973   }
1974 
1975   if (free_handle_block() != NULL) {
1976     JNIHandleBlock* block = free_handle_block();
1977     set_free_handle_block(NULL);
1978     JNIHandleBlock::release_block(block);
1979   }
1980 
1981   // These have to be removed while this is still a valid thread.
1982   remove_stack_guard_pages();
1983 
1984   if (UseTLAB) {
1985     tlab().make_parsable(true);  // retire TLAB, if any
1986   }
1987 
1988 #if INCLUDE_ALL_GCS
1989   if (UseG1GC) {
1990     flush_barrier_queues();
1991   }
1992 #endif // INCLUDE_ALL_GCS
1993 
1994   Threads::remove(this);
1995   delete this;
1996 }
1997 
1998 
1999 
2000 
2001 JavaThread* JavaThread::active() {
2002   Thread* thread = ThreadLocalStorage::thread();
2003   assert(thread != NULL, "just checking");
2004   if (thread->is_Java_thread()) {
2005     return (JavaThread*) thread;
2006   } else {
2007     assert(thread->is_VM_thread(), "this must be a vm thread");
2008     VM_Operation* op = ((VMThread*) thread)->vm_operation();
2009     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2010     assert(ret->is_Java_thread(), "must be a Java thread");
2011     return ret;
2012   }
2013 }
2014 
2015 bool JavaThread::is_lock_owned(address adr) const {
2016   if (Thread::is_lock_owned(adr)) return true;
2017 
2018   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2019     if (chunk->contains(adr)) return true;
2020   }
2021 
2022   return false;
2023 }
2024 
2025 
2026 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2027   chunk->set_next(monitor_chunks());
2028   set_monitor_chunks(chunk);
2029 }
2030 
2031 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2032   guarantee(monitor_chunks() != NULL, "must be non empty");
2033   if (monitor_chunks() == chunk) {
2034     set_monitor_chunks(chunk->next());
2035   } else {
2036     MonitorChunk* prev = monitor_chunks();
2037     while (prev->next() != chunk) prev = prev->next();
2038     prev->set_next(chunk->next());
2039   }
2040 }
2041 
2042 // JVM support.
2043 
2044 // Note: this function shouldn't block if it's called in
2045 // _thread_in_native_trans state (such as from
2046 // check_special_condition_for_native_trans()).
2047 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2048 
2049   if (has_last_Java_frame() && has_async_condition()) {
2050     // If we are at a polling page safepoint (not a poll return)
2051     // then we must defer async exception because live registers
2052     // will be clobbered by the exception path. Poll return is
2053     // ok because the call we a returning from already collides
2054     // with exception handling registers and so there is no issue.
2055     // (The exception handling path kills call result registers but
2056     //  this is ok since the exception kills the result anyway).
2057 
2058     if (is_at_poll_safepoint()) {
2059       // if the code we are returning to has deoptimized we must defer
2060       // the exception otherwise live registers get clobbered on the
2061       // exception path before deoptimization is able to retrieve them.
2062       //
2063       RegisterMap map(this, false);
2064       frame caller_fr = last_frame().sender(&map);
2065       assert(caller_fr.is_compiled_frame(), "what?");
2066       if (caller_fr.is_deoptimized_frame()) {
2067         if (TraceExceptions) {
2068           ResourceMark rm;
2069           tty->print_cr("deferred async exception at compiled safepoint");
2070         }
2071         return;
2072       }
2073     }
2074   }
2075 
2076   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2077   if (condition == _no_async_condition) {
2078     // Conditions have changed since has_special_runtime_exit_condition()
2079     // was called:
2080     // - if we were here only because of an external suspend request,
2081     //   then that was taken care of above (or cancelled) so we are done
2082     // - if we were here because of another async request, then it has
2083     //   been cleared between the has_special_runtime_exit_condition()
2084     //   and now so again we are done
2085     return;
2086   }
2087 
2088   // Check for pending async. exception
2089   if (_pending_async_exception != NULL) {
2090     // Only overwrite an already pending exception, if it is not a threadDeath.
2091     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2092 
2093       // We cannot call Exceptions::_throw(...) here because we cannot block
2094       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2095 
2096       if (TraceExceptions) {
2097         ResourceMark rm;
2098         tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2099         if (has_last_Java_frame()) {
2100           frame f = last_frame();
2101           tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2102         }
2103         tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2104       }
2105       _pending_async_exception = NULL;
2106       clear_has_async_exception();
2107     }
2108   }
2109 
2110   if (check_unsafe_error &&
2111       condition == _async_unsafe_access_error && !has_pending_exception()) {
2112     condition = _no_async_condition;  // done
2113     switch (thread_state()) {
2114     case _thread_in_vm: {
2115       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       ThreadInVMfromNative tiv(this);
2120       JavaThread* THREAD = this;
2121       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2122     }
2123     case _thread_in_Java: {
2124       ThreadInVMfromJava tiv(this);
2125       JavaThread* THREAD = this;
2126       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2127     }
2128     default:
2129       ShouldNotReachHere();
2130     }
2131   }
2132 
2133   assert(condition == _no_async_condition || has_pending_exception() ||
2134          (!check_unsafe_error && condition == _async_unsafe_access_error),
2135          "must have handled the async condition, if no exception");
2136 }
2137 
2138 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2139   //
2140   // Check for pending external suspend. Internal suspend requests do
2141   // not use handle_special_runtime_exit_condition().
2142   // If JNIEnv proxies are allowed, don't self-suspend if the target
2143   // thread is not the current thread. In older versions of jdbx, jdbx
2144   // threads could call into the VM with another thread's JNIEnv so we
2145   // can be here operating on behalf of a suspended thread (4432884).
2146   bool do_self_suspend = is_external_suspend_with_lock();
2147   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2148     //
2149     // Because thread is external suspended the safepoint code will count
2150     // thread as at a safepoint. This can be odd because we can be here
2151     // as _thread_in_Java which would normally transition to _thread_blocked
2152     // at a safepoint. We would like to mark the thread as _thread_blocked
2153     // before calling java_suspend_self like all other callers of it but
2154     // we must then observe proper safepoint protocol. (We can't leave
2155     // _thread_blocked with a safepoint in progress). However we can be
2156     // here as _thread_in_native_trans so we can't use a normal transition
2157     // constructor/destructor pair because they assert on that type of
2158     // transition. We could do something like:
2159     //
2160     // JavaThreadState state = thread_state();
2161     // set_thread_state(_thread_in_vm);
2162     // {
2163     //   ThreadBlockInVM tbivm(this);
2164     //   java_suspend_self()
2165     // }
2166     // set_thread_state(_thread_in_vm_trans);
2167     // if (safepoint) block;
2168     // set_thread_state(state);
2169     //
2170     // but that is pretty messy. Instead we just go with the way the
2171     // code has worked before and note that this is the only path to
2172     // java_suspend_self that doesn't put the thread in _thread_blocked
2173     // mode.
2174 
2175     frame_anchor()->make_walkable(this);
2176     java_suspend_self();
2177 
2178     // We might be here for reasons in addition to the self-suspend request
2179     // so check for other async requests.
2180   }
2181 
2182   if (check_asyncs) {
2183     check_and_handle_async_exceptions();
2184   }
2185 }
2186 
2187 void JavaThread::send_thread_stop(oop java_throwable)  {
2188   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2189   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2190   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2191 
2192   // Do not throw asynchronous exceptions against the compiler thread
2193   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2194   if (!can_call_java()) return;
2195 
2196   {
2197     // Actually throw the Throwable against the target Thread - however
2198     // only if there is no thread death exception installed already.
2199     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2200       // If the topmost frame is a runtime stub, then we are calling into
2201       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2202       // must deoptimize the caller before continuing, as the compiled  exception handler table
2203       // may not be valid
2204       if (has_last_Java_frame()) {
2205         frame f = last_frame();
2206         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2207           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2208           RegisterMap reg_map(this, UseBiasedLocking);
2209           frame compiled_frame = f.sender(&reg_map);
2210           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2211             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2212           }
2213         }
2214       }
2215 
2216       // Set async. pending exception in thread.
2217       set_pending_async_exception(java_throwable);
2218 
2219       if (TraceExceptions) {
2220         ResourceMark rm;
2221         tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2222       }
2223       // for AbortVMOnException flag
2224       NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2225     }
2226   }
2227 
2228 
2229   // Interrupt thread so it will wake up from a potential wait()
2230   Thread::interrupt(this);
2231 }
2232 
2233 // External suspension mechanism.
2234 //
2235 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2236 // to any VM_locks and it is at a transition
2237 // Self-suspension will happen on the transition out of the vm.
2238 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2239 //
2240 // Guarantees on return:
2241 //   + Target thread will not execute any new bytecode (that's why we need to
2242 //     force a safepoint)
2243 //   + Target thread will not enter any new monitors
2244 //
2245 void JavaThread::java_suspend() {
2246   { MutexLocker mu(Threads_lock);
2247     if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2248       return;
2249     }
2250   }
2251 
2252   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2253     if (!is_external_suspend()) {
2254       // a racing resume has cancelled us; bail out now
2255       return;
2256     }
2257 
2258     // suspend is done
2259     uint32_t debug_bits = 0;
2260     // Warning: is_ext_suspend_completed() may temporarily drop the
2261     // SR_lock to allow the thread to reach a stable thread state if
2262     // it is currently in a transient thread state.
2263     if (is_ext_suspend_completed(false /* !called_by_wait */,
2264                                  SuspendRetryDelay, &debug_bits)) {
2265       return;
2266     }
2267   }
2268 
2269   VM_ForceSafepoint vm_suspend;
2270   VMThread::execute(&vm_suspend);
2271 }
2272 
2273 // Part II of external suspension.
2274 // A JavaThread self suspends when it detects a pending external suspend
2275 // request. This is usually on transitions. It is also done in places
2276 // where continuing to the next transition would surprise the caller,
2277 // e.g., monitor entry.
2278 //
2279 // Returns the number of times that the thread self-suspended.
2280 //
2281 // Note: DO NOT call java_suspend_self() when you just want to block current
2282 //       thread. java_suspend_self() is the second stage of cooperative
2283 //       suspension for external suspend requests and should only be used
2284 //       to complete an external suspend request.
2285 //
2286 int JavaThread::java_suspend_self() {
2287   int ret = 0;
2288 
2289   // we are in the process of exiting so don't suspend
2290   if (is_exiting()) {
2291     clear_external_suspend();
2292     return ret;
2293   }
2294 
2295   assert(_anchor.walkable() ||
2296          (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2297          "must have walkable stack");
2298 
2299   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2300 
2301   assert(!this->is_ext_suspended(),
2302          "a thread trying to self-suspend should not already be suspended");
2303 
2304   if (this->is_suspend_equivalent()) {
2305     // If we are self-suspending as a result of the lifting of a
2306     // suspend equivalent condition, then the suspend_equivalent
2307     // flag is not cleared until we set the ext_suspended flag so
2308     // that wait_for_ext_suspend_completion() returns consistent
2309     // results.
2310     this->clear_suspend_equivalent();
2311   }
2312 
2313   // A racing resume may have cancelled us before we grabbed SR_lock
2314   // above. Or another external suspend request could be waiting for us
2315   // by the time we return from SR_lock()->wait(). The thread
2316   // that requested the suspension may already be trying to walk our
2317   // stack and if we return now, we can change the stack out from under
2318   // it. This would be a "bad thing (TM)" and cause the stack walker
2319   // to crash. We stay self-suspended until there are no more pending
2320   // external suspend requests.
2321   while (is_external_suspend()) {
2322     ret++;
2323     this->set_ext_suspended();
2324 
2325     // _ext_suspended flag is cleared by java_resume()
2326     while (is_ext_suspended()) {
2327       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2328     }
2329   }
2330 
2331   return ret;
2332 }
2333 
2334 #ifdef ASSERT
2335 // verify the JavaThread has not yet been published in the Threads::list, and
2336 // hence doesn't need protection from concurrent access at this stage
2337 void JavaThread::verify_not_published() {
2338   if (!Threads_lock->owned_by_self()) {
2339     MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
2340     assert(!Threads::includes(this),
2341            "java thread shouldn't have been published yet!");
2342   } else {
2343     assert(!Threads::includes(this),
2344            "java thread shouldn't have been published yet!");
2345   }
2346 }
2347 #endif
2348 
2349 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2350 // progress or when _suspend_flags is non-zero.
2351 // Current thread needs to self-suspend if there is a suspend request and/or
2352 // block if a safepoint is in progress.
2353 // Async exception ISN'T checked.
2354 // Note only the ThreadInVMfromNative transition can call this function
2355 // directly and when thread state is _thread_in_native_trans
2356 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2357   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2358 
2359   JavaThread *curJT = JavaThread::current();
2360   bool do_self_suspend = thread->is_external_suspend();
2361 
2362   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2363 
2364   // If JNIEnv proxies are allowed, don't self-suspend if the target
2365   // thread is not the current thread. In older versions of jdbx, jdbx
2366   // threads could call into the VM with another thread's JNIEnv so we
2367   // can be here operating on behalf of a suspended thread (4432884).
2368   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2369     JavaThreadState state = thread->thread_state();
2370 
2371     // We mark this thread_blocked state as a suspend-equivalent so
2372     // that a caller to is_ext_suspend_completed() won't be confused.
2373     // The suspend-equivalent state is cleared by java_suspend_self().
2374     thread->set_suspend_equivalent();
2375 
2376     // If the safepoint code sees the _thread_in_native_trans state, it will
2377     // wait until the thread changes to other thread state. There is no
2378     // guarantee on how soon we can obtain the SR_lock and complete the
2379     // self-suspend request. It would be a bad idea to let safepoint wait for
2380     // too long. Temporarily change the state to _thread_blocked to
2381     // let the VM thread know that this thread is ready for GC. The problem
2382     // of changing thread state is that safepoint could happen just after
2383     // java_suspend_self() returns after being resumed, and VM thread will
2384     // see the _thread_blocked state. We must check for safepoint
2385     // after restoring the state and make sure we won't leave while a safepoint
2386     // is in progress.
2387     thread->set_thread_state(_thread_blocked);
2388     thread->java_suspend_self();
2389     thread->set_thread_state(state);
2390     // Make sure new state is seen by VM thread
2391     if (os::is_MP()) {
2392       if (UseMembar) {
2393         // Force a fence between the write above and read below
2394         OrderAccess::fence();
2395       } else {
2396         // Must use this rather than serialization page in particular on Windows
2397         InterfaceSupport::serialize_memory(thread);
2398       }
2399     }
2400   }
2401 
2402   if (SafepointSynchronize::do_call_back()) {
2403     // If we are safepointing, then block the caller which may not be
2404     // the same as the target thread (see above).
2405     SafepointSynchronize::block(curJT);
2406   }
2407 
2408   if (thread->is_deopt_suspend()) {
2409     thread->clear_deopt_suspend();
2410     RegisterMap map(thread, false);
2411     frame f = thread->last_frame();
2412     while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2413       f = f.sender(&map);
2414     }
2415     if (f.id() == thread->must_deopt_id()) {
2416       thread->clear_must_deopt_id();
2417       f.deoptimize(thread);
2418     } else {
2419       fatal("missed deoptimization!");
2420     }
2421   }
2422 }
2423 
2424 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2425 // progress or when _suspend_flags is non-zero.
2426 // Current thread needs to self-suspend if there is a suspend request and/or
2427 // block if a safepoint is in progress.
2428 // Also check for pending async exception (not including unsafe access error).
2429 // Note only the native==>VM/Java barriers can call this function and when
2430 // thread state is _thread_in_native_trans.
2431 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2432   check_safepoint_and_suspend_for_native_trans(thread);
2433 
2434   if (thread->has_async_exception()) {
2435     // We are in _thread_in_native_trans state, don't handle unsafe
2436     // access error since that may block.
2437     thread->check_and_handle_async_exceptions(false);
2438   }
2439 }
2440 
2441 // This is a variant of the normal
2442 // check_special_condition_for_native_trans with slightly different
2443 // semantics for use by critical native wrappers.  It does all the
2444 // normal checks but also performs the transition back into
2445 // thread_in_Java state.  This is required so that critical natives
2446 // can potentially block and perform a GC if they are the last thread
2447 // exiting the GC_locker.
2448 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2449   check_special_condition_for_native_trans(thread);
2450 
2451   // Finish the transition
2452   thread->set_thread_state(_thread_in_Java);
2453 
2454   if (thread->do_critical_native_unlock()) {
2455     ThreadInVMfromJavaNoAsyncException tiv(thread);
2456     GC_locker::unlock_critical(thread);
2457     thread->clear_critical_native_unlock();
2458   }
2459 }
2460 
2461 // We need to guarantee the Threads_lock here, since resumes are not
2462 // allowed during safepoint synchronization
2463 // Can only resume from an external suspension
2464 void JavaThread::java_resume() {
2465   assert_locked_or_safepoint(Threads_lock);
2466 
2467   // Sanity check: thread is gone, has started exiting or the thread
2468   // was not externally suspended.
2469   if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2470     return;
2471   }
2472 
2473   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2474 
2475   clear_external_suspend();
2476 
2477   if (is_ext_suspended()) {
2478     clear_ext_suspended();
2479     SR_lock()->notify_all();
2480   }
2481 }
2482 
2483 void JavaThread::create_stack_guard_pages() {
2484   if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2485   address low_addr = stack_base() - stack_size();
2486   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2487 
2488   int allocate = os::allocate_stack_guard_pages();
2489   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2490 
2491   if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2492     warning("Attempt to allocate stack guard pages failed.");
2493     return;
2494   }
2495 
2496   if (os::guard_memory((char *) low_addr, len)) {
2497     _stack_guard_state = stack_guard_enabled;
2498   } else {
2499     warning("Attempt to protect stack guard pages failed.");
2500     if (os::uncommit_memory((char *) low_addr, len)) {
2501       warning("Attempt to deallocate stack guard pages failed.");
2502     }
2503   }
2504 }
2505 
2506 void JavaThread::remove_stack_guard_pages() {
2507   assert(Thread::current() == this, "from different thread");
2508   if (_stack_guard_state == stack_guard_unused) return;
2509   address low_addr = stack_base() - stack_size();
2510   size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2511 
2512   if (os::allocate_stack_guard_pages()) {
2513     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2514       _stack_guard_state = stack_guard_unused;
2515     } else {
2516       warning("Attempt to deallocate stack guard pages failed.");
2517     }
2518   } else {
2519     if (_stack_guard_state == stack_guard_unused) return;
2520     if (os::unguard_memory((char *) low_addr, len)) {
2521       _stack_guard_state = stack_guard_unused;
2522     } else {
2523       warning("Attempt to unprotect stack guard pages failed.");
2524     }
2525   }
2526 }
2527 
2528 void JavaThread::enable_stack_yellow_zone() {
2529   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2530   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2531 
2532   // The base notation is from the stacks point of view, growing downward.
2533   // We need to adjust it to work correctly with guard_memory()
2534   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2535 
2536   guarantee(base < stack_base(), "Error calculating stack yellow zone");
2537   guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2538 
2539   if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2540     _stack_guard_state = stack_guard_enabled;
2541   } else {
2542     warning("Attempt to guard stack yellow zone failed.");
2543   }
2544   enable_register_stack_guard();
2545 }
2546 
2547 void JavaThread::disable_stack_yellow_zone() {
2548   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2549   assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2550 
2551   // Simply return if called for a thread that does not use guard pages.
2552   if (_stack_guard_state == stack_guard_unused) return;
2553 
2554   // The base notation is from the stacks point of view, growing downward.
2555   // We need to adjust it to work correctly with guard_memory()
2556   address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2557 
2558   if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2559     _stack_guard_state = stack_guard_yellow_disabled;
2560   } else {
2561     warning("Attempt to unguard stack yellow zone failed.");
2562   }
2563   disable_register_stack_guard();
2564 }
2565 
2566 void JavaThread::enable_stack_red_zone() {
2567   // The base notation is from the stacks point of view, growing downward.
2568   // We need to adjust it to work correctly with guard_memory()
2569   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2570   address base = stack_red_zone_base() - stack_red_zone_size();
2571 
2572   guarantee(base < stack_base(), "Error calculating stack red zone");
2573   guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2574 
2575   if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2576     warning("Attempt to guard stack red zone failed.");
2577   }
2578 }
2579 
2580 void JavaThread::disable_stack_red_zone() {
2581   // The base notation is from the stacks point of view, growing downward.
2582   // We need to adjust it to work correctly with guard_memory()
2583   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2584   address base = stack_red_zone_base() - stack_red_zone_size();
2585   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2586     warning("Attempt to unguard stack red zone failed.");
2587   }
2588 }
2589 
2590 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2591   // ignore is there is no stack
2592   if (!has_last_Java_frame()) return;
2593   // traverse the stack frames. Starts from top frame.
2594   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2595     frame* fr = fst.current();
2596     f(fr, fst.register_map());
2597   }
2598 }
2599 
2600 
2601 #ifndef PRODUCT
2602 // Deoptimization
2603 // Function for testing deoptimization
2604 void JavaThread::deoptimize() {
2605   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2606   StackFrameStream fst(this, UseBiasedLocking);
2607   bool deopt = false;           // Dump stack only if a deopt actually happens.
2608   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2609   // Iterate over all frames in the thread and deoptimize
2610   for (; !fst.is_done(); fst.next()) {
2611     if (fst.current()->can_be_deoptimized()) {
2612 
2613       if (only_at) {
2614         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2615         // consists of comma or carriage return separated numbers so
2616         // search for the current bci in that string.
2617         address pc = fst.current()->pc();
2618         nmethod* nm =  (nmethod*) fst.current()->cb();
2619         ScopeDesc* sd = nm->scope_desc_at(pc);
2620         char buffer[8];
2621         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2622         size_t len = strlen(buffer);
2623         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2624         while (found != NULL) {
2625           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2626               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2627             // Check that the bci found is bracketed by terminators.
2628             break;
2629           }
2630           found = strstr(found + 1, buffer);
2631         }
2632         if (!found) {
2633           continue;
2634         }
2635       }
2636 
2637       if (DebugDeoptimization && !deopt) {
2638         deopt = true; // One-time only print before deopt
2639         tty->print_cr("[BEFORE Deoptimization]");
2640         trace_frames();
2641         trace_stack();
2642       }
2643       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2644     }
2645   }
2646 
2647   if (DebugDeoptimization && deopt) {
2648     tty->print_cr("[AFTER Deoptimization]");
2649     trace_frames();
2650   }
2651 }
2652 
2653 
2654 // Make zombies
2655 void JavaThread::make_zombies() {
2656   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2657     if (fst.current()->can_be_deoptimized()) {
2658       // it is a Java nmethod
2659       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2660       nm->make_not_entrant();
2661     }
2662   }
2663 }
2664 #endif // PRODUCT
2665 
2666 
2667 void JavaThread::deoptimized_wrt_marked_nmethods() {
2668   if (!has_last_Java_frame()) return;
2669   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2670   StackFrameStream fst(this, UseBiasedLocking);
2671   for (; !fst.is_done(); fst.next()) {
2672     if (fst.current()->should_be_deoptimized()) {






2673       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2674     }
2675   }
2676 }
2677 
2678 
2679 // If the caller is a NamedThread, then remember, in the current scope,
2680 // the given JavaThread in its _processed_thread field.
2681 class RememberProcessedThread: public StackObj {
2682   NamedThread* _cur_thr;
2683  public:
2684   RememberProcessedThread(JavaThread* jthr) {
2685     Thread* thread = Thread::current();
2686     if (thread->is_Named_thread()) {
2687       _cur_thr = (NamedThread *)thread;
2688       _cur_thr->set_processed_thread(jthr);
2689     } else {
2690       _cur_thr = NULL;
2691     }
2692   }
2693 
2694   ~RememberProcessedThread() {
2695     if (_cur_thr) {
2696       _cur_thr->set_processed_thread(NULL);
2697     }
2698   }
2699 };
2700 
2701 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2702   // Verify that the deferred card marks have been flushed.
2703   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2704 
2705   // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2706   // since there may be more than one thread using each ThreadProfiler.
2707 
2708   // Traverse the GCHandles
2709   Thread::oops_do(f, cld_f, cf);
2710 
2711   JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2712 
2713   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2714          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2715 
2716   if (has_last_Java_frame()) {
2717     // Record JavaThread to GC thread
2718     RememberProcessedThread rpt(this);
2719 
2720     // Traverse the privileged stack
2721     if (_privileged_stack_top != NULL) {
2722       _privileged_stack_top->oops_do(f);
2723     }
2724 
2725     // traverse the registered growable array
2726     if (_array_for_gc != NULL) {
2727       for (int index = 0; index < _array_for_gc->length(); index++) {
2728         f->do_oop(_array_for_gc->adr_at(index));
2729       }
2730     }
2731 
2732     // Traverse the monitor chunks
2733     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2734       chunk->oops_do(f);
2735     }
2736 
2737     // Traverse the execution stack
2738     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2739       fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2740     }
2741   }
2742 
2743   // callee_target is never live across a gc point so NULL it here should
2744   // it still contain a methdOop.
2745 
2746   set_callee_target(NULL);
2747 
2748   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2749   // If we have deferred set_locals there might be oops waiting to be
2750   // written
2751   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2752   if (list != NULL) {
2753     for (int i = 0; i < list->length(); i++) {
2754       list->at(i)->oops_do(f);
2755     }
2756   }
2757 
2758   // Traverse instance variables at the end since the GC may be moving things
2759   // around using this function
2760   f->do_oop((oop*) &_threadObj);
2761   f->do_oop((oop*) &_vm_result);
2762   f->do_oop((oop*) &_exception_oop);
2763   f->do_oop((oop*) &_pending_async_exception);
2764 
2765   if (jvmti_thread_state() != NULL) {
2766     jvmti_thread_state()->oops_do(f);
2767   }
2768 }
2769 
2770 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2771   Thread::nmethods_do(cf);  // (super method is a no-op)
2772 
2773   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2774          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2775 
2776   if (has_last_Java_frame()) {
2777     // Traverse the execution stack
2778     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2779       fst.current()->nmethods_do(cf);
2780     }
2781   }
2782 }
2783 
2784 void JavaThread::metadata_do(void f(Metadata*)) {
2785   if (has_last_Java_frame()) {
2786     // Traverse the execution stack to call f() on the methods in the stack
2787     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2788       fst.current()->metadata_do(f);
2789     }
2790   } else if (is_Compiler_thread()) {
2791     // need to walk ciMetadata in current compile tasks to keep alive.
2792     CompilerThread* ct = (CompilerThread*)this;
2793     if (ct->env() != NULL) {
2794       ct->env()->metadata_do(f);
2795     }
2796     if (ct->task() != NULL) {
2797       ct->task()->metadata_do(f);
2798     }
2799   }
2800 }
2801 
2802 // Printing
2803 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2804   switch (_thread_state) {
2805   case _thread_uninitialized:     return "_thread_uninitialized";
2806   case _thread_new:               return "_thread_new";
2807   case _thread_new_trans:         return "_thread_new_trans";
2808   case _thread_in_native:         return "_thread_in_native";
2809   case _thread_in_native_trans:   return "_thread_in_native_trans";
2810   case _thread_in_vm:             return "_thread_in_vm";
2811   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2812   case _thread_in_Java:           return "_thread_in_Java";
2813   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2814   case _thread_blocked:           return "_thread_blocked";
2815   case _thread_blocked_trans:     return "_thread_blocked_trans";
2816   default:                        return "unknown thread state";
2817   }
2818 }
2819 
2820 #ifndef PRODUCT
2821 void JavaThread::print_thread_state_on(outputStream *st) const {
2822   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2823 };
2824 void JavaThread::print_thread_state() const {
2825   print_thread_state_on(tty);
2826 }
2827 #endif // PRODUCT
2828 
2829 // Called by Threads::print() for VM_PrintThreads operation
2830 void JavaThread::print_on(outputStream *st) const {
2831   st->print("\"%s\" ", get_thread_name());
2832   oop thread_oop = threadObj();
2833   if (thread_oop != NULL) {
2834     st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2835     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2836     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2837   }
2838   Thread::print_on(st);
2839   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2840   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2841   if (thread_oop != NULL) {
2842     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2843   }
2844 #ifndef PRODUCT
2845   print_thread_state_on(st);
2846   _safepoint_state->print_on(st);
2847 #endif // PRODUCT
2848 }
2849 
2850 // Called by fatal error handler. The difference between this and
2851 // JavaThread::print() is that we can't grab lock or allocate memory.
2852 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2853   st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2854   oop thread_obj = threadObj();
2855   if (thread_obj != NULL) {
2856     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2857   }
2858   st->print(" [");
2859   st->print("%s", _get_thread_state_name(_thread_state));
2860   if (osthread()) {
2861     st->print(", id=%d", osthread()->thread_id());
2862   }
2863   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2864             _stack_base - _stack_size, _stack_base);
2865   st->print("]");
2866   return;
2867 }
2868 
2869 // Verification
2870 
2871 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2872 
2873 void JavaThread::verify() {
2874   // Verify oops in the thread.
2875   oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2876 
2877   // Verify the stack frames.
2878   frames_do(frame_verify);
2879 }
2880 
2881 // CR 6300358 (sub-CR 2137150)
2882 // Most callers of this method assume that it can't return NULL but a
2883 // thread may not have a name whilst it is in the process of attaching to
2884 // the VM - see CR 6412693, and there are places where a JavaThread can be
2885 // seen prior to having it's threadObj set (eg JNI attaching threads and
2886 // if vm exit occurs during initialization). These cases can all be accounted
2887 // for such that this method never returns NULL.
2888 const char* JavaThread::get_thread_name() const {
2889 #ifdef ASSERT
2890   // early safepoints can hit while current thread does not yet have TLS
2891   if (!SafepointSynchronize::is_at_safepoint()) {
2892     Thread *cur = Thread::current();
2893     if (!(cur->is_Java_thread() && cur == this)) {
2894       // Current JavaThreads are allowed to get their own name without
2895       // the Threads_lock.
2896       assert_locked_or_safepoint(Threads_lock);
2897     }
2898   }
2899 #endif // ASSERT
2900   return get_thread_name_string();
2901 }
2902 
2903 // Returns a non-NULL representation of this thread's name, or a suitable
2904 // descriptive string if there is no set name
2905 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2906   const char* name_str;
2907   oop thread_obj = threadObj();
2908   if (thread_obj != NULL) {
2909     oop name = java_lang_Thread::name(thread_obj);
2910     if (name != NULL) {
2911       if (buf == NULL) {
2912         name_str = java_lang_String::as_utf8_string(name);
2913       } else {
2914         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2915       }
2916     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2917       name_str = "<no-name - thread is attaching>";
2918     } else {
2919       name_str = Thread::name();
2920     }
2921   } else {
2922     name_str = Thread::name();
2923   }
2924   assert(name_str != NULL, "unexpected NULL thread name");
2925   return name_str;
2926 }
2927 
2928 
2929 const char* JavaThread::get_threadgroup_name() const {
2930   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2931   oop thread_obj = threadObj();
2932   if (thread_obj != NULL) {
2933     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2934     if (thread_group != NULL) {
2935       typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2936       // ThreadGroup.name can be null
2937       if (name != NULL) {
2938         const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2939         return str;
2940       }
2941     }
2942   }
2943   return NULL;
2944 }
2945 
2946 const char* JavaThread::get_parent_name() const {
2947   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2948   oop thread_obj = threadObj();
2949   if (thread_obj != NULL) {
2950     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2951     if (thread_group != NULL) {
2952       oop parent = java_lang_ThreadGroup::parent(thread_group);
2953       if (parent != NULL) {
2954         typeArrayOop name = java_lang_ThreadGroup::name(parent);
2955         // ThreadGroup.name can be null
2956         if (name != NULL) {
2957           const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2958           return str;
2959         }
2960       }
2961     }
2962   }
2963   return NULL;
2964 }
2965 
2966 ThreadPriority JavaThread::java_priority() const {
2967   oop thr_oop = threadObj();
2968   if (thr_oop == NULL) return NormPriority; // Bootstrapping
2969   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2970   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2971   return priority;
2972 }
2973 
2974 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2975 
2976   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2977   // Link Java Thread object <-> C++ Thread
2978 
2979   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2980   // and put it into a new Handle.  The Handle "thread_oop" can then
2981   // be used to pass the C++ thread object to other methods.
2982 
2983   // Set the Java level thread object (jthread) field of the
2984   // new thread (a JavaThread *) to C++ thread object using the
2985   // "thread_oop" handle.
2986 
2987   // Set the thread field (a JavaThread *) of the
2988   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2989 
2990   Handle thread_oop(Thread::current(),
2991                     JNIHandles::resolve_non_null(jni_thread));
2992   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2993          "must be initialized");
2994   set_threadObj(thread_oop());
2995   java_lang_Thread::set_thread(thread_oop(), this);
2996 
2997   if (prio == NoPriority) {
2998     prio = java_lang_Thread::priority(thread_oop());
2999     assert(prio != NoPriority, "A valid priority should be present");
3000   }
3001 
3002   // Push the Java priority down to the native thread; needs Threads_lock
3003   Thread::set_priority(this, prio);
3004 
3005   prepare_ext();
3006 
3007   // Add the new thread to the Threads list and set it in motion.
3008   // We must have threads lock in order to call Threads::add.
3009   // It is crucial that we do not block before the thread is
3010   // added to the Threads list for if a GC happens, then the java_thread oop
3011   // will not be visited by GC.
3012   Threads::add(this);
3013 }
3014 
3015 oop JavaThread::current_park_blocker() {
3016   // Support for JSR-166 locks
3017   oop thread_oop = threadObj();
3018   if (thread_oop != NULL &&
3019       JDK_Version::current().supports_thread_park_blocker()) {
3020     return java_lang_Thread::park_blocker(thread_oop);
3021   }
3022   return NULL;
3023 }
3024 
3025 
3026 void JavaThread::print_stack_on(outputStream* st) {
3027   if (!has_last_Java_frame()) return;
3028   ResourceMark rm;
3029   HandleMark   hm;
3030 
3031   RegisterMap reg_map(this);
3032   vframe* start_vf = last_java_vframe(&reg_map);
3033   int count = 0;
3034   for (vframe* f = start_vf; f; f = f->sender()) {
3035     if (f->is_java_frame()) {
3036       javaVFrame* jvf = javaVFrame::cast(f);
3037       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3038 
3039       // Print out lock information
3040       if (JavaMonitorsInStackTrace) {
3041         jvf->print_lock_info_on(st, count);
3042       }
3043     } else {
3044       // Ignore non-Java frames
3045     }
3046 
3047     // Bail-out case for too deep stacks
3048     count++;
3049     if (MaxJavaStackTraceDepth == count) return;
3050   }
3051 }
3052 
3053 
3054 // JVMTI PopFrame support
3055 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3056   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3057   if (in_bytes(size_in_bytes) != 0) {
3058     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3059     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3060     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3061   }
3062 }
3063 
3064 void* JavaThread::popframe_preserved_args() {
3065   return _popframe_preserved_args;
3066 }
3067 
3068 ByteSize JavaThread::popframe_preserved_args_size() {
3069   return in_ByteSize(_popframe_preserved_args_size);
3070 }
3071 
3072 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3073   int sz = in_bytes(popframe_preserved_args_size());
3074   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3075   return in_WordSize(sz / wordSize);
3076 }
3077 
3078 void JavaThread::popframe_free_preserved_args() {
3079   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3080   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3081   _popframe_preserved_args = NULL;
3082   _popframe_preserved_args_size = 0;
3083 }
3084 
3085 #ifndef PRODUCT
3086 
3087 void JavaThread::trace_frames() {
3088   tty->print_cr("[Describe stack]");
3089   int frame_no = 1;
3090   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3091     tty->print("  %d. ", frame_no++);
3092     fst.current()->print_value_on(tty, this);
3093     tty->cr();
3094   }
3095 }
3096 
3097 class PrintAndVerifyOopClosure: public OopClosure {
3098  protected:
3099   template <class T> inline void do_oop_work(T* p) {
3100     oop obj = oopDesc::load_decode_heap_oop(p);
3101     if (obj == NULL) return;
3102     tty->print(INTPTR_FORMAT ": ", p);
3103     if (obj->is_oop_or_null()) {
3104       if (obj->is_objArray()) {
3105         tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3106       } else {
3107         obj->print();
3108       }
3109     } else {
3110       tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3111     }
3112     tty->cr();
3113   }
3114  public:
3115   virtual void do_oop(oop* p) { do_oop_work(p); }
3116   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3117 };
3118 
3119 
3120 static void oops_print(frame* f, const RegisterMap *map) {
3121   PrintAndVerifyOopClosure print;
3122   f->print_value();
3123   f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3124 }
3125 
3126 // Print our all the locations that contain oops and whether they are
3127 // valid or not.  This useful when trying to find the oldest frame
3128 // where an oop has gone bad since the frame walk is from youngest to
3129 // oldest.
3130 void JavaThread::trace_oops() {
3131   tty->print_cr("[Trace oops]");
3132   frames_do(oops_print);
3133 }
3134 
3135 
3136 #ifdef ASSERT
3137 // Print or validate the layout of stack frames
3138 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3139   ResourceMark rm;
3140   PRESERVE_EXCEPTION_MARK;
3141   FrameValues values;
3142   int frame_no = 0;
3143   for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3144     fst.current()->describe(values, ++frame_no);
3145     if (depth == frame_no) break;
3146   }
3147   if (validate_only) {
3148     values.validate();
3149   } else {
3150     tty->print_cr("[Describe stack layout]");
3151     values.print(this);
3152   }
3153 }
3154 #endif
3155 
3156 void JavaThread::trace_stack_from(vframe* start_vf) {
3157   ResourceMark rm;
3158   int vframe_no = 1;
3159   for (vframe* f = start_vf; f; f = f->sender()) {
3160     if (f->is_java_frame()) {
3161       javaVFrame::cast(f)->print_activation(vframe_no++);
3162     } else {
3163       f->print();
3164     }
3165     if (vframe_no > StackPrintLimit) {
3166       tty->print_cr("...<more frames>...");
3167       return;
3168     }
3169   }
3170 }
3171 
3172 
3173 void JavaThread::trace_stack() {
3174   if (!has_last_Java_frame()) return;
3175   ResourceMark rm;
3176   HandleMark   hm;
3177   RegisterMap reg_map(this);
3178   trace_stack_from(last_java_vframe(&reg_map));
3179 }
3180 
3181 
3182 #endif // PRODUCT
3183 
3184 
3185 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3186   assert(reg_map != NULL, "a map must be given");
3187   frame f = last_frame();
3188   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3189     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3190   }
3191   return NULL;
3192 }
3193 
3194 
3195 Klass* JavaThread::security_get_caller_class(int depth) {
3196   vframeStream vfst(this);
3197   vfst.security_get_caller_frame(depth);
3198   if (!vfst.at_end()) {
3199     return vfst.method()->method_holder();
3200   }
3201   return NULL;
3202 }
3203 
3204 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3205   assert(thread->is_Compiler_thread(), "must be compiler thread");
3206   CompileBroker::compiler_thread_loop();
3207 }
3208 
3209 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3210   NMethodSweeper::sweeper_loop();
3211 }
3212 
3213 // Create a CompilerThread
3214 CompilerThread::CompilerThread(CompileQueue* queue,
3215                                CompilerCounters* counters)
3216                                : JavaThread(&compiler_thread_entry) {
3217   _env   = NULL;
3218   _log   = NULL;
3219   _task  = NULL;
3220   _queue = queue;
3221   _counters = counters;
3222   _buffer_blob = NULL;
3223   _compiler = NULL;
3224 
3225 #ifndef PRODUCT
3226   _ideal_graph_printer = NULL;
3227 #endif
3228 }
3229 
3230 bool CompilerThread::can_call_java() const {
3231   return _compiler != NULL && _compiler->is_jvmci();
3232 }
3233 
3234 // Create sweeper thread
3235 CodeCacheSweeperThread::CodeCacheSweeperThread()
3236 : JavaThread(&sweeper_thread_entry) {
3237   _scanned_nmethod = NULL;
3238 }
3239 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3240   JavaThread::oops_do(f, cld_f, cf);
3241   if (_scanned_nmethod != NULL && cf != NULL) {
3242     // Safepoints can occur when the sweeper is scanning an nmethod so
3243     // process it here to make sure it isn't unloaded in the middle of
3244     // a scan.
3245     cf->do_code_blob(_scanned_nmethod);
3246   }
3247 }
3248 
3249 
3250 // ======= Threads ========
3251 
3252 // The Threads class links together all active threads, and provides
3253 // operations over all threads.  It is protected by its own Mutex
3254 // lock, which is also used in other contexts to protect thread
3255 // operations from having the thread being operated on from exiting
3256 // and going away unexpectedly (e.g., safepoint synchronization)
3257 
3258 JavaThread* Threads::_thread_list = NULL;
3259 int         Threads::_number_of_threads = 0;
3260 int         Threads::_number_of_non_daemon_threads = 0;
3261 int         Threads::_return_code = 0;
3262 int         Threads::_thread_claim_parity = 0;
3263 size_t      JavaThread::_stack_size_at_create = 0;
3264 #ifdef ASSERT
3265 bool        Threads::_vm_complete = false;
3266 #endif
3267 
3268 // All JavaThreads
3269 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3270 
3271 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3272 void Threads::threads_do(ThreadClosure* tc) {
3273   assert_locked_or_safepoint(Threads_lock);
3274   // ALL_JAVA_THREADS iterates through all JavaThreads
3275   ALL_JAVA_THREADS(p) {
3276     tc->do_thread(p);
3277   }
3278   // Someday we could have a table or list of all non-JavaThreads.
3279   // For now, just manually iterate through them.
3280   tc->do_thread(VMThread::vm_thread());
3281   Universe::heap()->gc_threads_do(tc);
3282   WatcherThread *wt = WatcherThread::watcher_thread();
3283   // Strictly speaking, the following NULL check isn't sufficient to make sure
3284   // the data for WatcherThread is still valid upon being examined. However,
3285   // considering that WatchThread terminates when the VM is on the way to
3286   // exit at safepoint, the chance of the above is extremely small. The right
3287   // way to prevent termination of WatcherThread would be to acquire
3288   // Terminator_lock, but we can't do that without violating the lock rank
3289   // checking in some cases.
3290   if (wt != NULL) {
3291     tc->do_thread(wt);
3292   }
3293 
3294   // If CompilerThreads ever become non-JavaThreads, add them here
3295 }
3296 
3297 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3298   TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3299 
3300   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3301     create_vm_init_libraries();
3302   }
3303 
3304   initialize_class(vmSymbols::java_lang_String(), CHECK);
3305 
3306   // Initialize java_lang.System (needed before creating the thread)
3307   initialize_class(vmSymbols::java_lang_System(), CHECK);
3308   // The VM creates & returns objects of this class. Make sure it's initialized.
3309   initialize_class(vmSymbols::java_lang_Class(), CHECK);
3310   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3311   Handle thread_group = create_initial_thread_group(CHECK);
3312   Universe::set_main_thread_group(thread_group());
3313   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3314   oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3315   main_thread->set_threadObj(thread_object);
3316   // Set thread status to running since main thread has
3317   // been started and running.
3318   java_lang_Thread::set_thread_status(thread_object,
3319                                       java_lang_Thread::RUNNABLE);
3320 
3321   // The VM preresolves methods to these classes. Make sure that they get initialized
3322   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3323   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3324   call_initializeSystemClass(CHECK);
3325 
3326   // get the Java runtime name after java.lang.System is initialized
3327   JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3328   JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3329 
3330   // an instance of OutOfMemory exception has been allocated earlier
3331   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3332   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3333   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3334   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3335   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3336   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3337   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3338   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3339 }
3340 
3341 void Threads::initialize_jsr292_core_classes(TRAPS) {
3342   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3343   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3344   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3345 }
3346 
3347 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3348   extern void JDK_Version_init();
3349 
3350   // Preinitialize version info.
3351   VM_Version::early_initialize();
3352 
3353   // Check version
3354   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3355 
3356   // Initialize the output stream module
3357   ostream_init();
3358 
3359   // Process java launcher properties.
3360   Arguments::process_sun_java_launcher_properties(args);
3361 
3362   // Initialize the os module before using TLS
3363   os::init();
3364 
3365   // Initialize system properties.
3366   Arguments::init_system_properties();
3367 
3368   // So that JDK version can be used as a discriminator when parsing arguments
3369   JDK_Version_init();
3370 
3371   // Update/Initialize System properties after JDK version number is known
3372   Arguments::init_version_specific_system_properties();
3373 
3374   // Parse arguments
3375   jint parse_result = Arguments::parse(args);
3376   if (parse_result != JNI_OK) return parse_result;
3377 
3378   os::init_before_ergo();
3379 
3380   jint ergo_result = Arguments::apply_ergo();
3381   if (ergo_result != JNI_OK) return ergo_result;
3382 
3383   // Final check of all ranges after ergonomics which may change values.
3384   if (!CommandLineFlagRangeList::check_ranges()) {
3385     return JNI_EINVAL;
3386   }
3387 
3388   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3389   bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3390   if (!constraint_result) {
3391     return JNI_EINVAL;
3392   }
3393 
3394   if (PauseAtStartup) {
3395     os::pause();
3396   }
3397 
3398   HOTSPOT_VM_INIT_BEGIN();
3399 
3400   // Record VM creation timing statistics
3401   TraceVmCreationTime create_vm_timer;
3402   create_vm_timer.start();
3403 
3404   // Timing (must come after argument parsing)
3405   TraceTime timer("Create VM", TraceStartupTime);
3406 
3407   // Initialize the os module after parsing the args
3408   jint os_init_2_result = os::init_2();
3409   if (os_init_2_result != JNI_OK) return os_init_2_result;
3410 
3411   jint adjust_after_os_result = Arguments::adjust_after_os();
3412   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3413 
3414   // initialize TLS
3415   ThreadLocalStorage::init();
3416 
3417   // Initialize output stream logging
3418   ostream_init_log();
3419 
3420   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3421   // Must be before create_vm_init_agents()
3422   if (Arguments::init_libraries_at_startup()) {
3423     convert_vm_init_libraries_to_agents();
3424   }
3425 
3426   // Launch -agentlib/-agentpath and converted -Xrun agents
3427   if (Arguments::init_agents_at_startup()) {
3428     create_vm_init_agents();
3429   }
3430 
3431   // Initialize Threads state
3432   _thread_list = NULL;
3433   _number_of_threads = 0;
3434   _number_of_non_daemon_threads = 0;
3435 
3436   // Initialize global data structures and create system classes in heap
3437   vm_init_globals();
3438 
3439 #if INCLUDE_JVMCI
3440   if (JVMCICounterSize > 0) {
3441     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3442     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3443   } else {
3444     JavaThread::_jvmci_old_thread_counters = NULL;
3445   }
3446 #endif // INCLUDE_JVMCI
3447 
3448   // Attach the main thread to this os thread
3449   JavaThread* main_thread = new JavaThread();
3450   main_thread->set_thread_state(_thread_in_vm);
3451   // must do this before set_active_handles and initialize_thread_local_storage
3452   // Note: on solaris initialize_thread_local_storage() will (indirectly)
3453   // change the stack size recorded here to one based on the java thread
3454   // stacksize. This adjusted size is what is used to figure the placement
3455   // of the guard pages.
3456   main_thread->record_stack_base_and_size();
3457   main_thread->initialize_thread_local_storage();
3458 
3459   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3460 
3461   if (!main_thread->set_as_starting_thread()) {
3462     vm_shutdown_during_initialization(
3463                                       "Failed necessary internal allocation. Out of swap space");
3464     delete main_thread;
3465     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3466     return JNI_ENOMEM;
3467   }
3468 
3469   // Enable guard page *after* os::create_main_thread(), otherwise it would
3470   // crash Linux VM, see notes in os_linux.cpp.
3471   main_thread->create_stack_guard_pages();
3472 
3473   // Initialize Java-Level synchronization subsystem
3474   ObjectMonitor::Initialize();
3475 
3476   // Initialize global modules
3477   jint status = init_globals();
3478   if (status != JNI_OK) {
3479     delete main_thread;
3480     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3481     return status;
3482   }
3483 
3484   // Should be done after the heap is fully created
3485   main_thread->cache_global_variables();
3486 
3487   HandleMark hm;
3488 
3489   { MutexLocker mu(Threads_lock);
3490     Threads::add(main_thread);
3491   }
3492 
3493   // Any JVMTI raw monitors entered in onload will transition into
3494   // real raw monitor. VM is setup enough here for raw monitor enter.
3495   JvmtiExport::transition_pending_onload_raw_monitors();
3496 
3497   // Create the VMThread
3498   { TraceTime timer("Start VMThread", TraceStartupTime);
3499     VMThread::create();
3500     Thread* vmthread = VMThread::vm_thread();
3501 
3502     if (!os::create_thread(vmthread, os::vm_thread)) {
3503       vm_exit_during_initialization("Cannot create VM thread. "
3504                                     "Out of system resources.");
3505     }
3506 
3507     // Wait for the VM thread to become ready, and VMThread::run to initialize
3508     // Monitors can have spurious returns, must always check another state flag
3509     {
3510       MutexLocker ml(Notify_lock);
3511       os::start_thread(vmthread);
3512       while (vmthread->active_handles() == NULL) {
3513         Notify_lock->wait();
3514       }
3515     }
3516   }
3517 
3518   assert(Universe::is_fully_initialized(), "not initialized");
3519   if (VerifyDuringStartup) {
3520     // Make sure we're starting with a clean slate.
3521     VM_Verify verify_op;
3522     VMThread::execute(&verify_op);
3523   }
3524 
3525   Thread* THREAD = Thread::current();
3526 
3527   // At this point, the Universe is initialized, but we have not executed
3528   // any byte code.  Now is a good time (the only time) to dump out the
3529   // internal state of the JVM for sharing.
3530   if (DumpSharedSpaces) {
3531     MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3532     ShouldNotReachHere();
3533   }
3534 
3535   // Always call even when there are not JVMTI environments yet, since environments
3536   // may be attached late and JVMTI must track phases of VM execution
3537   JvmtiExport::enter_start_phase();
3538 
3539   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3540   JvmtiExport::post_vm_start();
3541 
3542   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3543 
3544   // We need this for ClassDataSharing - the initial vm.info property is set
3545   // with the default value of CDS "sharing" which may be reset through
3546   // command line options.
3547   reset_vm_info_property(CHECK_JNI_ERR);
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   HOTSPOT_VM_INIT_END();
3563 
3564   // record VM initialization completion time
3565 #if INCLUDE_MANAGEMENT
3566   Management::record_vm_init_completed();
3567 #endif // INCLUDE_MANAGEMENT
3568 
3569   // Compute system loader. Note that this has to occur after set_init_completed, since
3570   // valid exceptions may be thrown in the process.
3571   // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3572   // set_init_completed has just been called, causing exceptions not to be shortcut
3573   // anymore. We call vm_exit_during_initialization directly instead.
3574   SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3575 
3576 #if INCLUDE_ALL_GCS
3577   // Support for ConcurrentMarkSweep. This should be cleaned up
3578   // and better encapsulated. The ugly nested if test would go away
3579   // once things are properly refactored. XXX YSR
3580   if (UseConcMarkSweepGC || UseG1GC) {
3581     if (UseConcMarkSweepGC) {
3582       ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3583     } else {
3584       ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3585     }
3586   }
3587 #endif // INCLUDE_ALL_GCS
3588 
3589   // Always call even when there are not JVMTI environments yet, since environments
3590   // may be attached late and JVMTI must track phases of VM execution
3591   JvmtiExport::enter_live_phase();
3592 
3593   // Signal Dispatcher needs to be started before VMInit event is posted
3594   os::signal_init();
3595 
3596   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3597   if (!DisableAttachMechanism) {
3598     AttachListener::vm_start();
3599     if (StartAttachListener || AttachListener::init_at_startup()) {
3600       AttachListener::init();
3601     }
3602   }
3603 
3604   // Launch -Xrun agents
3605   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3606   // back-end can launch with -Xdebug -Xrunjdwp.
3607   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3608     create_vm_init_libraries();
3609   }
3610 
3611   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3612   JvmtiExport::post_vm_initialized();
3613 
3614   if (TRACE_START() != JNI_OK) {
3615     vm_exit_during_initialization("Failed to start tracing backend.");
3616   }
3617 
3618   if (CleanChunkPoolAsync) {
3619     Chunk::start_chunk_pool_cleaner_task();
3620   }
3621 
3622 #if INCLUDE_JVMCI
3623   if (EnableJVMCI) {
3624     const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3625     if (jvmciCompiler != NULL) {
3626       JVMCIRuntime::save_compiler(jvmciCompiler);
3627     }
3628   }
3629 #endif // INCLUDE_JVMCI
3630 
3631   // initialize compiler(s)
3632 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3633   CompileBroker::compilation_init();
3634 #endif
3635 
3636   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3637   // It is done after compilers are initialized, because otherwise compilations of
3638   // signature polymorphic MH intrinsics can be missed
3639   // (see SystemDictionary::find_method_handle_intrinsic).
3640   initialize_jsr292_core_classes(CHECK_JNI_ERR);
3641 
3642 #if INCLUDE_MANAGEMENT
3643   Management::initialize(THREAD);
3644 
3645   if (HAS_PENDING_EXCEPTION) {
3646     // management agent fails to start possibly due to
3647     // configuration problem and is responsible for printing
3648     // stack trace if appropriate. Simply exit VM.
3649     vm_exit(1);
3650   }
3651 #endif // INCLUDE_MANAGEMENT
3652 
3653   if (Arguments::has_profile())       FlatProfiler::engage(main_thread, true);
3654   if (MemProfiling)                   MemProfiler::engage();
3655   StatSampler::engage();
3656   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3657 
3658   BiasedLocking::init();
3659 
3660 #if INCLUDE_RTM_OPT
3661   RTMLockingCounters::init();
3662 #endif
3663 
3664   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3665     call_postVMInitHook(THREAD);
3666     // The Java side of PostVMInitHook.run must deal with all
3667     // exceptions and provide means of diagnosis.
3668     if (HAS_PENDING_EXCEPTION) {
3669       CLEAR_PENDING_EXCEPTION;
3670     }
3671   }
3672 
3673   {
3674     MutexLocker ml(PeriodicTask_lock);
3675     // Make sure the WatcherThread can be started by WatcherThread::start()
3676     // or by dynamic enrollment.
3677     WatcherThread::make_startable();
3678     // Start up the WatcherThread if there are any periodic tasks
3679     // NOTE:  All PeriodicTasks should be registered by now. If they
3680     //   aren't, late joiners might appear to start slowly (we might
3681     //   take a while to process their first tick).
3682     if (PeriodicTask::num_tasks() > 0) {
3683       WatcherThread::start();
3684     }
3685   }
3686 
3687   CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3688 
3689   create_vm_timer.end();
3690 #ifdef ASSERT
3691   _vm_complete = true;
3692 #endif
3693   return JNI_OK;
3694 }
3695 
3696 // type for the Agent_OnLoad and JVM_OnLoad entry points
3697 extern "C" {
3698   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3699 }
3700 // Find a command line agent library and return its entry point for
3701 //         -agentlib:  -agentpath:   -Xrun
3702 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3703 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3704                                     const char *on_load_symbols[],
3705                                     size_t num_symbol_entries) {
3706   OnLoadEntry_t on_load_entry = NULL;
3707   void *library = NULL;
3708 
3709   if (!agent->valid()) {
3710     char buffer[JVM_MAXPATHLEN];
3711     char ebuf[1024] = "";
3712     const char *name = agent->name();
3713     const char *msg = "Could not find agent library ";
3714 
3715     // First check to see if agent is statically linked into executable
3716     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3717       library = agent->os_lib();
3718     } else if (agent->is_absolute_path()) {
3719       library = os::dll_load(name, ebuf, sizeof ebuf);
3720       if (library == NULL) {
3721         const char *sub_msg = " in absolute path, with error: ";
3722         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3723         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3724         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3725         // If we can't find the agent, exit.
3726         vm_exit_during_initialization(buf, NULL);
3727         FREE_C_HEAP_ARRAY(char, buf);
3728       }
3729     } else {
3730       // Try to load the agent from the standard dll directory
3731       if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3732                              name)) {
3733         library = os::dll_load(buffer, ebuf, sizeof ebuf);
3734       }
3735       if (library == NULL) { // Try the local directory
3736         char ns[1] = {0};
3737         if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3738           library = os::dll_load(buffer, ebuf, sizeof ebuf);
3739         }
3740         if (library == NULL) {
3741           const char *sub_msg = " on the library path, with error: ";
3742           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3743           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3744           jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3745           // If we can't find the agent, exit.
3746           vm_exit_during_initialization(buf, NULL);
3747           FREE_C_HEAP_ARRAY(char, buf);
3748         }
3749       }
3750     }
3751     agent->set_os_lib(library);
3752     agent->set_valid();
3753   }
3754 
3755   // Find the OnLoad function.
3756   on_load_entry =
3757     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3758                                                           false,
3759                                                           on_load_symbols,
3760                                                           num_symbol_entries));
3761   return on_load_entry;
3762 }
3763 
3764 // Find the JVM_OnLoad entry point
3765 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3766   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3767   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3768 }
3769 
3770 // Find the Agent_OnLoad entry point
3771 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3772   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3773   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3774 }
3775 
3776 // For backwards compatibility with -Xrun
3777 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3778 // treated like -agentpath:
3779 // Must be called before agent libraries are created
3780 void Threads::convert_vm_init_libraries_to_agents() {
3781   AgentLibrary* agent;
3782   AgentLibrary* next;
3783 
3784   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3785     next = agent->next();  // cache the next agent now as this agent may get moved off this list
3786     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3787 
3788     // If there is an JVM_OnLoad function it will get called later,
3789     // otherwise see if there is an Agent_OnLoad
3790     if (on_load_entry == NULL) {
3791       on_load_entry = lookup_agent_on_load(agent);
3792       if (on_load_entry != NULL) {
3793         // switch it to the agent list -- so that Agent_OnLoad will be called,
3794         // JVM_OnLoad won't be attempted and Agent_OnUnload will
3795         Arguments::convert_library_to_agent(agent);
3796       } else {
3797         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3798       }
3799     }
3800   }
3801 }
3802 
3803 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
3804 // Invokes Agent_OnLoad
3805 // Called very early -- before JavaThreads exist
3806 void Threads::create_vm_init_agents() {
3807   extern struct JavaVM_ main_vm;
3808   AgentLibrary* agent;
3809 
3810   JvmtiExport::enter_onload_phase();
3811 
3812   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3813     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
3814 
3815     if (on_load_entry != NULL) {
3816       // Invoke the Agent_OnLoad function
3817       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3818       if (err != JNI_OK) {
3819         vm_exit_during_initialization("agent library failed to init", agent->name());
3820       }
3821     } else {
3822       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3823     }
3824   }
3825   JvmtiExport::enter_primordial_phase();
3826 }
3827 
3828 extern "C" {
3829   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3830 }
3831 
3832 void Threads::shutdown_vm_agents() {
3833   // Send any Agent_OnUnload notifications
3834   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3835   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3836   extern struct JavaVM_ main_vm;
3837   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3838 
3839     // Find the Agent_OnUnload function.
3840     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3841                                                    os::find_agent_function(agent,
3842                                                    false,
3843                                                    on_unload_symbols,
3844                                                    num_symbol_entries));
3845 
3846     // Invoke the Agent_OnUnload function
3847     if (unload_entry != NULL) {
3848       JavaThread* thread = JavaThread::current();
3849       ThreadToNativeFromVM ttn(thread);
3850       HandleMark hm(thread);
3851       (*unload_entry)(&main_vm);
3852     }
3853   }
3854 }
3855 
3856 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3857 // Invokes JVM_OnLoad
3858 void Threads::create_vm_init_libraries() {
3859   extern struct JavaVM_ main_vm;
3860   AgentLibrary* agent;
3861 
3862   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3863     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3864 
3865     if (on_load_entry != NULL) {
3866       // Invoke the JVM_OnLoad function
3867       JavaThread* thread = JavaThread::current();
3868       ThreadToNativeFromVM ttn(thread);
3869       HandleMark hm(thread);
3870       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3871       if (err != JNI_OK) {
3872         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3873       }
3874     } else {
3875       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3876     }
3877   }
3878 }
3879 
3880 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3881   assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3882 
3883   JavaThread* java_thread = NULL;
3884   // Sequential search for now.  Need to do better optimization later.
3885   for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3886     oop tobj = thread->threadObj();
3887     if (!thread->is_exiting() &&
3888         tobj != NULL &&
3889         java_tid == java_lang_Thread::thread_id(tobj)) {
3890       java_thread = thread;
3891       break;
3892     }
3893   }
3894   return java_thread;
3895 }
3896 
3897 
3898 // Last thread running calls java.lang.Shutdown.shutdown()
3899 void JavaThread::invoke_shutdown_hooks() {
3900   HandleMark hm(this);
3901 
3902   // We could get here with a pending exception, if so clear it now.
3903   if (this->has_pending_exception()) {
3904     this->clear_pending_exception();
3905   }
3906 
3907   EXCEPTION_MARK;
3908   Klass* k =
3909     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3910                                       THREAD);
3911   if (k != NULL) {
3912     // SystemDictionary::resolve_or_null will return null if there was
3913     // an exception.  If we cannot load the Shutdown class, just don't
3914     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
3915     // and finalizers (if runFinalizersOnExit is set) won't be run.
3916     // Note that if a shutdown hook was registered or runFinalizersOnExit
3917     // was called, the Shutdown class would have already been loaded
3918     // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3919     instanceKlassHandle shutdown_klass (THREAD, k);
3920     JavaValue result(T_VOID);
3921     JavaCalls::call_static(&result,
3922                            shutdown_klass,
3923                            vmSymbols::shutdown_method_name(),
3924                            vmSymbols::void_method_signature(),
3925                            THREAD);
3926   }
3927   CLEAR_PENDING_EXCEPTION;
3928 }
3929 
3930 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3931 // the program falls off the end of main(). Another VM exit path is through
3932 // vm_exit() when the program calls System.exit() to return a value or when
3933 // there is a serious error in VM. The two shutdown paths are not exactly
3934 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3935 // and VM_Exit op at VM level.
3936 //
3937 // Shutdown sequence:
3938 //   + Shutdown native memory tracking if it is on
3939 //   + Wait until we are the last non-daemon thread to execute
3940 //     <-- every thing is still working at this moment -->
3941 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3942 //        shutdown hooks, run finalizers if finalization-on-exit
3943 //   + Call before_exit(), prepare for VM exit
3944 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3945 //        currently the only user of this mechanism is File.deleteOnExit())
3946 //      > stop flat profiler, StatSampler, watcher thread, CMS threads,
3947 //        post thread end and vm death events to JVMTI,
3948 //        stop signal thread
3949 //   + Call JavaThread::exit(), it will:
3950 //      > release JNI handle blocks, remove stack guard pages
3951 //      > remove this thread from Threads list
3952 //     <-- no more Java code from this thread after this point -->
3953 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3954 //     the compiler threads at safepoint
3955 //     <-- do not use anything that could get blocked by Safepoint -->
3956 //   + Disable tracing at JNI/JVM barriers
3957 //   + Set _vm_exited flag for threads that are still running native code
3958 //   + Delete this thread
3959 //   + Call exit_globals()
3960 //      > deletes tty
3961 //      > deletes PerfMemory resources
3962 //   + Return to caller
3963 
3964 bool Threads::destroy_vm() {
3965   JavaThread* thread = JavaThread::current();
3966 
3967 #ifdef ASSERT
3968   _vm_complete = false;
3969 #endif
3970   // Wait until we are the last non-daemon thread to execute
3971   { MutexLocker nu(Threads_lock);
3972     while (Threads::number_of_non_daemon_threads() > 1)
3973       // This wait should make safepoint checks, wait without a timeout,
3974       // and wait as a suspend-equivalent condition.
3975       //
3976       // Note: If the FlatProfiler is running and this thread is waiting
3977       // for another non-daemon thread to finish, then the FlatProfiler
3978       // is waiting for the external suspend request on this thread to
3979       // complete. wait_for_ext_suspend_completion() will eventually
3980       // timeout, but that takes time. Making this wait a suspend-
3981       // equivalent condition solves that timeout problem.
3982       //
3983       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3984                          Mutex::_as_suspend_equivalent_flag);
3985   }
3986 
3987   // Hang forever on exit if we are reporting an error.
3988   if (ShowMessageBoxOnError && is_error_reported()) {
3989     os::infinite_sleep();
3990   }
3991   os::wait_for_keypress_at_exit();
3992 
3993   // run Java level shutdown hooks
3994   thread->invoke_shutdown_hooks();
3995 
3996   before_exit(thread);
3997 
3998   thread->exit(true);
3999 
4000   // Stop VM thread.
4001   {
4002     // 4945125 The vm thread comes to a safepoint during exit.
4003     // GC vm_operations can get caught at the safepoint, and the
4004     // heap is unparseable if they are caught. Grab the Heap_lock
4005     // to prevent this. The GC vm_operations will not be able to
4006     // queue until after the vm thread is dead. After this point,
4007     // we'll never emerge out of the safepoint before the VM exits.
4008 
4009     MutexLocker ml(Heap_lock);
4010 
4011     VMThread::wait_for_vm_thread_exit();
4012     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4013     VMThread::destroy();
4014   }
4015 
4016   // clean up ideal graph printers
4017 #if defined(COMPILER2) && !defined(PRODUCT)
4018   IdealGraphPrinter::clean_up();
4019 #endif
4020 
4021   // Now, all Java threads are gone except daemon threads. Daemon threads
4022   // running Java code or in VM are stopped by the Safepoint. However,
4023   // daemon threads executing native code are still running.  But they
4024   // will be stopped at native=>Java/VM barriers. Note that we can't
4025   // simply kill or suspend them, as it is inherently deadlock-prone.
4026 
4027 #ifndef PRODUCT
4028   // disable function tracing at JNI/JVM barriers
4029   TraceJNICalls = false;
4030   TraceJVMCalls = false;
4031   TraceRuntimeCalls = false;
4032 #endif
4033 
4034   VM_Exit::set_vm_exited();
4035 
4036   notify_vm_shutdown();
4037 
4038   delete thread;
4039 
4040 #if INCLUDE_JVMCI
4041   if (JVMCICounterSize > 0) {
4042     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4043   }
4044 #endif
4045 
4046   // exit_globals() will delete tty
4047   exit_globals();
4048 
4049   return true;
4050 }
4051 
4052 
4053 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4054   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4055   return is_supported_jni_version(version);
4056 }
4057 
4058 
4059 jboolean Threads::is_supported_jni_version(jint version) {
4060   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4061   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4062   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4063   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4064   return JNI_FALSE;
4065 }
4066 
4067 
4068 void Threads::add(JavaThread* p, bool force_daemon) {
4069   // The threads lock must be owned at this point
4070   assert_locked_or_safepoint(Threads_lock);
4071 
4072   // See the comment for this method in thread.hpp for its purpose and
4073   // why it is called here.
4074   p->initialize_queues();
4075   p->set_next(_thread_list);
4076   _thread_list = p;
4077   _number_of_threads++;
4078   oop threadObj = p->threadObj();
4079   bool daemon = true;
4080   // Bootstrapping problem: threadObj can be null for initial
4081   // JavaThread (or for threads attached via JNI)
4082   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4083     _number_of_non_daemon_threads++;
4084     daemon = false;
4085   }
4086 
4087   ThreadService::add_thread(p, daemon);
4088 
4089   // Possible GC point.
4090   Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4091 }
4092 
4093 void Threads::remove(JavaThread* p) {
4094   // Extra scope needed for Thread_lock, so we can check
4095   // that we do not remove thread without safepoint code notice
4096   { MutexLocker ml(Threads_lock);
4097 
4098     assert(includes(p), "p must be present");
4099 
4100     JavaThread* current = _thread_list;
4101     JavaThread* prev    = NULL;
4102 
4103     while (current != p) {
4104       prev    = current;
4105       current = current->next();
4106     }
4107 
4108     if (prev) {
4109       prev->set_next(current->next());
4110     } else {
4111       _thread_list = p->next();
4112     }
4113     _number_of_threads--;
4114     oop threadObj = p->threadObj();
4115     bool daemon = true;
4116     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4117       _number_of_non_daemon_threads--;
4118       daemon = false;
4119 
4120       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4121       // on destroy_vm will wake up.
4122       if (number_of_non_daemon_threads() == 1) {
4123         Threads_lock->notify_all();
4124       }
4125     }
4126     ThreadService::remove_thread(p, daemon);
4127 
4128     // Make sure that safepoint code disregard this thread. This is needed since
4129     // the thread might mess around with locks after this point. This can cause it
4130     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4131     // of this thread since it is removed from the queue.
4132     p->set_terminated_value();
4133   } // unlock Threads_lock
4134 
4135   // Since Events::log uses a lock, we grab it outside the Threads_lock
4136   Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4137 }
4138 
4139 // Threads_lock must be held when this is called (or must be called during a safepoint)
4140 bool Threads::includes(JavaThread* p) {
4141   assert(Threads_lock->is_locked(), "sanity check");
4142   ALL_JAVA_THREADS(q) {
4143     if (q == p) {
4144       return true;
4145     }
4146   }
4147   return false;
4148 }
4149 
4150 // Operations on the Threads list for GC.  These are not explicitly locked,
4151 // but the garbage collector must provide a safe context for them to run.
4152 // In particular, these things should never be called when the Threads_lock
4153 // is held by some other thread. (Note: the Safepoint abstraction also
4154 // uses the Threads_lock to guarantee this property. It also makes sure that
4155 // all threads gets blocked when exiting or starting).
4156 
4157 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4158   ALL_JAVA_THREADS(p) {
4159     p->oops_do(f, cld_f, cf);
4160   }
4161   VMThread::vm_thread()->oops_do(f, cld_f, cf);
4162 }
4163 
4164 void Threads::change_thread_claim_parity() {
4165   // Set the new claim parity.
4166   assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4167          "Not in range.");
4168   _thread_claim_parity++;
4169   if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4170   assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4171          "Not in range.");
4172 }
4173 
4174 #ifdef ASSERT
4175 void Threads::assert_all_threads_claimed() {
4176   ALL_JAVA_THREADS(p) {
4177     const int thread_parity = p->oops_do_parity();
4178     assert((thread_parity == _thread_claim_parity),
4179         err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4180   }
4181 }
4182 #endif // ASSERT
4183 
4184 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4185   int cp = Threads::thread_claim_parity();
4186   ALL_JAVA_THREADS(p) {
4187     if (p->claim_oops_do(is_par, cp)) {
4188       p->oops_do(f, cld_f, cf);
4189     }
4190   }
4191   VMThread* vmt = VMThread::vm_thread();
4192   if (vmt->claim_oops_do(is_par, cp)) {
4193     vmt->oops_do(f, cld_f, cf);
4194   }
4195 }
4196 
4197 #if INCLUDE_ALL_GCS
4198 // Used by ParallelScavenge
4199 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4200   ALL_JAVA_THREADS(p) {
4201     q->enqueue(new ThreadRootsTask(p));
4202   }
4203   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4204 }
4205 
4206 // Used by Parallel Old
4207 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4208   ALL_JAVA_THREADS(p) {
4209     q->enqueue(new ThreadRootsMarkingTask(p));
4210   }
4211   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4212 }
4213 #endif // INCLUDE_ALL_GCS
4214 
4215 void Threads::nmethods_do(CodeBlobClosure* cf) {
4216   ALL_JAVA_THREADS(p) {
4217     p->nmethods_do(cf);
4218   }
4219   VMThread::vm_thread()->nmethods_do(cf);
4220 }
4221 
4222 void Threads::metadata_do(void f(Metadata*)) {
4223   ALL_JAVA_THREADS(p) {
4224     p->metadata_do(f);
4225   }
4226 }
4227 
4228 class ThreadHandlesClosure : public ThreadClosure {
4229   void (*_f)(Metadata*);
4230  public:
4231   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4232   virtual void do_thread(Thread* thread) {
4233     thread->metadata_handles_do(_f);
4234   }
4235 };
4236 
4237 void Threads::metadata_handles_do(void f(Metadata*)) {
4238   // Only walk the Handles in Thread.
4239   ThreadHandlesClosure handles_closure(f);
4240   threads_do(&handles_closure);
4241 }
4242 
4243 void Threads::deoptimized_wrt_marked_nmethods() {
4244   ALL_JAVA_THREADS(p) {
4245     p->deoptimized_wrt_marked_nmethods();
4246   }
4247 }
4248 
4249 
4250 // Get count Java threads that are waiting to enter the specified monitor.
4251 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4252                                                          address monitor,
4253                                                          bool doLock) {
4254   assert(doLock || SafepointSynchronize::is_at_safepoint(),
4255          "must grab Threads_lock or be at safepoint");
4256   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4257 
4258   int i = 0;
4259   {
4260     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4261     ALL_JAVA_THREADS(p) {
4262       if (!p->can_call_java()) continue;
4263 
4264       address pending = (address)p->current_pending_monitor();
4265       if (pending == monitor) {             // found a match
4266         if (i < count) result->append(p);   // save the first count matches
4267         i++;
4268       }
4269     }
4270   }
4271   return result;
4272 }
4273 
4274 
4275 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4276                                                       bool doLock) {
4277   assert(doLock ||
4278          Threads_lock->owned_by_self() ||
4279          SafepointSynchronize::is_at_safepoint(),
4280          "must grab Threads_lock or be at safepoint");
4281 
4282   // NULL owner means not locked so we can skip the search
4283   if (owner == NULL) return NULL;
4284 
4285   {
4286     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4287     ALL_JAVA_THREADS(p) {
4288       // first, see if owner is the address of a Java thread
4289       if (owner == (address)p) return p;
4290     }
4291   }
4292   // Cannot assert on lack of success here since this function may be
4293   // used by code that is trying to report useful problem information
4294   // like deadlock detection.
4295   if (UseHeavyMonitors) return NULL;
4296 
4297   // If we didn't find a matching Java thread and we didn't force use of
4298   // heavyweight monitors, then the owner is the stack address of the
4299   // Lock Word in the owning Java thread's stack.
4300   //
4301   JavaThread* the_owner = NULL;
4302   {
4303     MutexLockerEx ml(doLock ? Threads_lock : NULL);
4304     ALL_JAVA_THREADS(q) {
4305       if (q->is_lock_owned(owner)) {
4306         the_owner = q;
4307         break;
4308       }
4309     }
4310   }
4311   // cannot assert on lack of success here; see above comment
4312   return the_owner;
4313 }
4314 
4315 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4316 void Threads::print_on(outputStream* st, bool print_stacks,
4317                        bool internal_format, bool print_concurrent_locks) {
4318   char buf[32];
4319   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4320 
4321   st->print_cr("Full thread dump %s (%s %s):",
4322                Abstract_VM_Version::vm_name(),
4323                Abstract_VM_Version::vm_release(),
4324                Abstract_VM_Version::vm_info_string());
4325   st->cr();
4326 
4327 #if INCLUDE_SERVICES
4328   // Dump concurrent locks
4329   ConcurrentLocksDump concurrent_locks;
4330   if (print_concurrent_locks) {
4331     concurrent_locks.dump_at_safepoint();
4332   }
4333 #endif // INCLUDE_SERVICES
4334 
4335   ALL_JAVA_THREADS(p) {
4336     ResourceMark rm;
4337     p->print_on(st);
4338     if (print_stacks) {
4339       if (internal_format) {
4340         p->trace_stack();
4341       } else {
4342         p->print_stack_on(st);
4343       }
4344     }
4345     st->cr();
4346 #if INCLUDE_SERVICES
4347     if (print_concurrent_locks) {
4348       concurrent_locks.print_locks_on(p, st);
4349     }
4350 #endif // INCLUDE_SERVICES
4351   }
4352 
4353   VMThread::vm_thread()->print_on(st);
4354   st->cr();
4355   Universe::heap()->print_gc_threads_on(st);
4356   WatcherThread* wt = WatcherThread::watcher_thread();
4357   if (wt != NULL) {
4358     wt->print_on(st);
4359     st->cr();
4360   }
4361   CompileBroker::print_compiler_threads_on(st);
4362   st->flush();
4363 }
4364 
4365 // Threads::print_on_error() is called by fatal error handler. It's possible
4366 // that VM is not at safepoint and/or current thread is inside signal handler.
4367 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4368 // memory (even in resource area), it might deadlock the error handler.
4369 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4370                              int buflen) {
4371   bool found_current = false;
4372   st->print_cr("Java Threads: ( => current thread )");
4373   ALL_JAVA_THREADS(thread) {
4374     bool is_current = (current == thread);
4375     found_current = found_current || is_current;
4376 
4377     st->print("%s", is_current ? "=>" : "  ");
4378 
4379     st->print(PTR_FORMAT, thread);
4380     st->print(" ");
4381     thread->print_on_error(st, buf, buflen);
4382     st->cr();
4383   }
4384   st->cr();
4385 
4386   st->print_cr("Other Threads:");
4387   if (VMThread::vm_thread()) {
4388     bool is_current = (current == VMThread::vm_thread());
4389     found_current = found_current || is_current;
4390     st->print("%s", current == VMThread::vm_thread() ? "=>" : "  ");
4391 
4392     st->print(PTR_FORMAT, VMThread::vm_thread());
4393     st->print(" ");
4394     VMThread::vm_thread()->print_on_error(st, buf, buflen);
4395     st->cr();
4396   }
4397   WatcherThread* wt = WatcherThread::watcher_thread();
4398   if (wt != NULL) {
4399     bool is_current = (current == wt);
4400     found_current = found_current || is_current;
4401     st->print("%s", is_current ? "=>" : "  ");
4402 
4403     st->print(PTR_FORMAT, wt);
4404     st->print(" ");
4405     wt->print_on_error(st, buf, buflen);
4406     st->cr();
4407   }
4408   if (!found_current) {
4409     st->cr();
4410     st->print("=>" PTR_FORMAT " (exited) ", current);
4411     current->print_on_error(st, buf, buflen);
4412     st->cr();
4413   }
4414 }
4415 
4416 // Internal SpinLock and Mutex
4417 // Based on ParkEvent
4418 
4419 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4420 //
4421 // We employ SpinLocks _only for low-contention, fixed-length
4422 // short-duration critical sections where we're concerned
4423 // about native mutex_t or HotSpot Mutex:: latency.
4424 // The mux construct provides a spin-then-block mutual exclusion
4425 // mechanism.
4426 //
4427 // Testing has shown that contention on the ListLock guarding gFreeList
4428 // is common.  If we implement ListLock as a simple SpinLock it's common
4429 // for the JVM to devolve to yielding with little progress.  This is true
4430 // despite the fact that the critical sections protected by ListLock are
4431 // extremely short.
4432 //
4433 // TODO-FIXME: ListLock should be of type SpinLock.
4434 // We should make this a 1st-class type, integrated into the lock
4435 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4436 // should have sufficient padding to avoid false-sharing and excessive
4437 // cache-coherency traffic.
4438 
4439 
4440 typedef volatile int SpinLockT;
4441 
4442 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4443   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4444     return;   // normal fast-path return
4445   }
4446 
4447   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4448   TEVENT(SpinAcquire - ctx);
4449   int ctr = 0;
4450   int Yields = 0;
4451   for (;;) {
4452     while (*adr != 0) {
4453       ++ctr;
4454       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4455         if (Yields > 5) {
4456           os::naked_short_sleep(1);
4457         } else {
4458           os::naked_yield();
4459           ++Yields;
4460         }
4461       } else {
4462         SpinPause();
4463       }
4464     }
4465     if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4466   }
4467 }
4468 
4469 void Thread::SpinRelease(volatile int * adr) {
4470   assert(*adr != 0, "invariant");
4471   OrderAccess::fence();      // guarantee at least release consistency.
4472   // Roach-motel semantics.
4473   // It's safe if subsequent LDs and STs float "up" into the critical section,
4474   // but prior LDs and STs within the critical section can't be allowed
4475   // to reorder or float past the ST that releases the lock.
4476   // Loads and stores in the critical section - which appear in program
4477   // order before the store that releases the lock - must also appear
4478   // before the store that releases the lock in memory visibility order.
4479   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4480   // the ST of 0 into the lock-word which releases the lock, so fence
4481   // more than covers this on all platforms.
4482   *adr = 0;
4483 }
4484 
4485 // muxAcquire and muxRelease:
4486 //
4487 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4488 //    The LSB of the word is set IFF the lock is held.
4489 //    The remainder of the word points to the head of a singly-linked list
4490 //    of threads blocked on the lock.
4491 //
4492 // *  The current implementation of muxAcquire-muxRelease uses its own
4493 //    dedicated Thread._MuxEvent instance.  If we're interested in
4494 //    minimizing the peak number of extant ParkEvent instances then
4495 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4496 //    as certain invariants were satisfied.  Specifically, care would need
4497 //    to be taken with regards to consuming unpark() "permits".
4498 //    A safe rule of thumb is that a thread would never call muxAcquire()
4499 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4500 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4501 //    consume an unpark() permit intended for monitorenter, for instance.
4502 //    One way around this would be to widen the restricted-range semaphore
4503 //    implemented in park().  Another alternative would be to provide
4504 //    multiple instances of the PlatformEvent() for each thread.  One
4505 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4506 //
4507 // *  Usage:
4508 //    -- Only as leaf locks
4509 //    -- for short-term locking only as muxAcquire does not perform
4510 //       thread state transitions.
4511 //
4512 // Alternatives:
4513 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4514 //    but with parking or spin-then-park instead of pure spinning.
4515 // *  Use Taura-Oyama-Yonenzawa locks.
4516 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4517 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4518 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4519 //    acquiring threads use timers (ParkTimed) to detect and recover from
4520 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4521 //    boundaries by using placement-new.
4522 // *  Augment MCS with advisory back-link fields maintained with CAS().
4523 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4524 //    The validity of the backlinks must be ratified before we trust the value.
4525 //    If the backlinks are invalid the exiting thread must back-track through the
4526 //    the forward links, which are always trustworthy.
4527 // *  Add a successor indication.  The LockWord is currently encoded as
4528 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4529 //    to provide the usual futile-wakeup optimization.
4530 //    See RTStt for details.
4531 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4532 //
4533 
4534 
4535 typedef volatile intptr_t MutexT;      // Mux Lock-word
4536 enum MuxBits { LOCKBIT = 1 };
4537 
4538 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4539   intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4540   if (w == 0) return;
4541   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4542     return;
4543   }
4544 
4545   TEVENT(muxAcquire - Contention);
4546   ParkEvent * const Self = Thread::current()->_MuxEvent;
4547   assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4548   for (;;) {
4549     int its = (os::is_MP() ? 100 : 0) + 1;
4550 
4551     // Optional spin phase: spin-then-park strategy
4552     while (--its >= 0) {
4553       w = *Lock;
4554       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4555         return;
4556       }
4557     }
4558 
4559     Self->reset();
4560     Self->OnList = intptr_t(Lock);
4561     // The following fence() isn't _strictly necessary as the subsequent
4562     // CAS() both serializes execution and ratifies the fetched *Lock value.
4563     OrderAccess::fence();
4564     for (;;) {
4565       w = *Lock;
4566       if ((w & LOCKBIT) == 0) {
4567         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4568           Self->OnList = 0;   // hygiene - allows stronger asserts
4569           return;
4570         }
4571         continue;      // Interference -- *Lock changed -- Just retry
4572       }
4573       assert(w & LOCKBIT, "invariant");
4574       Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4575       if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4576     }
4577 
4578     while (Self->OnList != 0) {
4579       Self->park();
4580     }
4581   }
4582 }
4583 
4584 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4585   intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4586   if (w == 0) return;
4587   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4588     return;
4589   }
4590 
4591   TEVENT(muxAcquire - Contention);
4592   ParkEvent * ReleaseAfter = NULL;
4593   if (ev == NULL) {
4594     ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4595   }
4596   assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4597   for (;;) {
4598     guarantee(ev->OnList == 0, "invariant");
4599     int its = (os::is_MP() ? 100 : 0) + 1;
4600 
4601     // Optional spin phase: spin-then-park strategy
4602     while (--its >= 0) {
4603       w = *Lock;
4604       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4605         if (ReleaseAfter != NULL) {
4606           ParkEvent::Release(ReleaseAfter);
4607         }
4608         return;
4609       }
4610     }
4611 
4612     ev->reset();
4613     ev->OnList = intptr_t(Lock);
4614     // The following fence() isn't _strictly necessary as the subsequent
4615     // CAS() both serializes execution and ratifies the fetched *Lock value.
4616     OrderAccess::fence();
4617     for (;;) {
4618       w = *Lock;
4619       if ((w & LOCKBIT) == 0) {
4620         if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4621           ev->OnList = 0;
4622           // We call ::Release while holding the outer lock, thus
4623           // artificially lengthening the critical section.
4624           // Consider deferring the ::Release() until the subsequent unlock(),
4625           // after we've dropped the outer lock.
4626           if (ReleaseAfter != NULL) {
4627             ParkEvent::Release(ReleaseAfter);
4628           }
4629           return;
4630         }
4631         continue;      // Interference -- *Lock changed -- Just retry
4632       }
4633       assert(w & LOCKBIT, "invariant");
4634       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4635       if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4636     }
4637 
4638     while (ev->OnList != 0) {
4639       ev->park();
4640     }
4641   }
4642 }
4643 
4644 // Release() must extract a successor from the list and then wake that thread.
4645 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4646 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4647 // Release() would :
4648 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4649 // (B) Extract a successor from the private list "in-hand"
4650 // (C) attempt to CAS() the residual back into *Lock over null.
4651 //     If there were any newly arrived threads and the CAS() would fail.
4652 //     In that case Release() would detach the RATs, re-merge the list in-hand
4653 //     with the RATs and repeat as needed.  Alternately, Release() might
4654 //     detach and extract a successor, but then pass the residual list to the wakee.
4655 //     The wakee would be responsible for reattaching and remerging before it
4656 //     competed for the lock.
4657 //
4658 // Both "pop" and DMR are immune from ABA corruption -- there can be
4659 // multiple concurrent pushers, but only one popper or detacher.
4660 // This implementation pops from the head of the list.  This is unfair,
4661 // but tends to provide excellent throughput as hot threads remain hot.
4662 // (We wake recently run threads first).
4663 //
4664 // All paths through muxRelease() will execute a CAS.
4665 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4666 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4667 // executed within the critical section are complete and globally visible before the
4668 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4669 void Thread::muxRelease(volatile intptr_t * Lock)  {
4670   for (;;) {
4671     const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4672     assert(w & LOCKBIT, "invariant");
4673     if (w == LOCKBIT) return;
4674     ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4675     assert(List != NULL, "invariant");
4676     assert(List->OnList == intptr_t(Lock), "invariant");
4677     ParkEvent * const nxt = List->ListNext;
4678     guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4679 
4680     // The following CAS() releases the lock and pops the head element.
4681     // The CAS() also ratifies the previously fetched lock-word value.
4682     if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4683       continue;
4684     }
4685     List->OnList = 0;
4686     OrderAccess::fence();
4687     List->unpark();
4688     return;
4689   }
4690 }
4691 
4692 
4693 void Threads::verify() {
4694   ALL_JAVA_THREADS(p) {
4695     p->verify();
4696   }
4697   VMThread* thread = VMThread::vm_thread();
4698   if (thread != NULL) thread->verify();
4699 }
--- EOF ---