rev 50464 : Thread Dump Extension (memory allocation)

   1 /*
   2  * Copyright (c) 1997, 2018, 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 "jvm.h"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/moduleEntry.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmSymbols.hpp"
  32 #include "code/codeCache.hpp"
  33 #include "code/scopeDesc.hpp"
  34 #include "compiler/compileBroker.hpp"
  35 #include "compiler/compileTask.hpp"
  36 #include "gc/shared/barrierSet.hpp"
  37 #include "gc/shared/gcId.hpp"
  38 #include "gc/shared/gcLocker.inline.hpp"
  39 #include "gc/shared/workgroup.hpp"
  40 #include "interpreter/interpreter.hpp"
  41 #include "interpreter/linkResolver.hpp"
  42 #include "interpreter/oopMapCache.hpp"
  43 #include "jfr/jfrEvents.hpp"
  44 #include "jfr/support/jfrThreadId.hpp"
  45 #include "jvmtifiles/jvmtiEnv.hpp"
  46 #include "logging/log.hpp"
  47 #include "logging/logConfiguration.hpp"
  48 #include "logging/logStream.hpp"
  49 #include "memory/allocation.inline.hpp"
  50 #include "memory/metaspaceShared.hpp"
  51 #include "memory/oopFactory.hpp"
  52 #include "memory/resourceArea.hpp"
  53 #include "memory/universe.hpp"
  54 #include "oops/access.inline.hpp"
  55 #include "oops/instanceKlass.hpp"
  56 #include "oops/objArrayOop.hpp"
  57 #include "oops/oop.inline.hpp"
  58 #include "oops/symbol.hpp"
  59 #include "oops/typeArrayOop.inline.hpp"
  60 #include "oops/verifyOopClosure.hpp"
  61 #include "prims/jvm_misc.hpp"
  62 #include "prims/jvmtiExport.hpp"
  63 #include "prims/jvmtiThreadState.hpp"
  64 #include "prims/privilegedStack.hpp"
  65 #include "runtime/arguments.hpp"
  66 #include "runtime/atomic.hpp"
  67 #include "runtime/biasedLocking.hpp"
  68 #include "runtime/flags/jvmFlagConstraintList.hpp"
  69 #include "runtime/flags/jvmFlagRangeList.hpp"
  70 #include "runtime/flags/jvmFlagWriteableList.hpp"
  71 #include "runtime/deoptimization.hpp"
  72 #include "runtime/frame.inline.hpp"
  73 #include "runtime/handshake.hpp"
  74 #include "runtime/init.hpp"
  75 #include "runtime/interfaceSupport.inline.hpp"
  76 #include "runtime/java.hpp"
  77 #include "runtime/javaCalls.hpp"
  78 #include "runtime/jniHandles.inline.hpp"
  79 #include "runtime/jniPeriodicChecker.hpp"
  80 #include "runtime/memprofiler.hpp"
  81 #include "runtime/mutexLocker.hpp"
  82 #include "runtime/objectMonitor.hpp"
  83 #include "runtime/orderAccess.hpp"
  84 #include "runtime/osThread.hpp"
  85 #include "runtime/prefetch.inline.hpp"
  86 #include "runtime/safepoint.hpp"
  87 #include "runtime/safepointMechanism.inline.hpp"
  88 #include "runtime/sharedRuntime.hpp"
  89 #include "runtime/statSampler.hpp"
  90 #include "runtime/stubRoutines.hpp"
  91 #include "runtime/sweeper.hpp"
  92 #include "runtime/task.hpp"
  93 #include "runtime/thread.inline.hpp"
  94 #include "runtime/threadCritical.hpp"
  95 #include "runtime/threadSMR.inline.hpp"
  96 #include "runtime/timer.hpp"
  97 #include "runtime/timerTrace.hpp"
  98 #include "runtime/vframe.inline.hpp"
  99 #include "runtime/vframeArray.hpp"
 100 #include "runtime/vframe_hp.hpp"
 101 #include "runtime/vmThread.hpp"
 102 #include "runtime/vm_operations.hpp"
 103 #include "runtime/vm_version.hpp"
 104 #include "services/attachListener.hpp"
 105 #include "services/management.hpp"
 106 #include "services/memTracker.hpp"
 107 #include "services/threadService.hpp"
 108 #include "utilities/align.hpp"
 109 #include "utilities/copy.hpp"
 110 #include "utilities/defaultStream.hpp"
 111 #include "utilities/dtrace.hpp"
 112 #include "utilities/events.hpp"
 113 #include "utilities/macros.hpp"
 114 #include "utilities/preserveException.hpp"
 115 #include "utilities/vmError.hpp"
 116 #if INCLUDE_JVMCI
 117 #include "jvmci/jvmciCompiler.hpp"
 118 #include "jvmci/jvmciRuntime.hpp"
 119 #include "logging/logHandle.hpp"
 120 #endif
 121 #ifdef COMPILER1
 122 #include "c1/c1_Compiler.hpp"
 123 #endif
 124 #ifdef COMPILER2
 125 #include "opto/c2compiler.hpp"
 126 #include "opto/idealGraphPrinter.hpp"
 127 #endif
 128 #if INCLUDE_RTM_OPT
 129 #include "runtime/rtmLocking.hpp"
 130 #endif
 131 #if INCLUDE_JFR
 132 #include "jfr/jfr.hpp"
 133 #endif
 134 
 135 // Initialization after module runtime initialization
 136 void universe_post_module_init();  // must happen after call_initPhase2
 137 
 138 #ifdef DTRACE_ENABLED
 139 
 140 // Only bother with this argument setup if dtrace is available
 141 
 142   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 143   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 144 
 145   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 146     {                                                                      \
 147       ResourceMark rm(this);                                               \
 148       int len = 0;                                                         \
 149       const char* name = (javathread)->get_thread_name();                  \
 150       len = strlen(name);                                                  \
 151       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 152         (char *) name, len,                                                \
 153         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 154         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 155         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 156     }
 157 
 158 #else //  ndef DTRACE_ENABLED
 159 
 160   #define DTRACE_THREAD_PROBE(probe, javathread)
 161 
 162 #endif // ndef DTRACE_ENABLED
 163 
 164 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 165 // Current thread is maintained as a thread-local variable
 166 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
 167 #endif
 168 // Class hierarchy
 169 // - Thread
 170 //   - VMThread
 171 //   - WatcherThread
 172 //   - ConcurrentMarkSweepThread
 173 //   - JavaThread
 174 //     - CompilerThread
 175 
 176 // ======= Thread ========
 177 // Support for forcing alignment of thread objects for biased locking
 178 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 179   if (UseBiasedLocking) {
 180     const int alignment = markOopDesc::biased_lock_alignment;
 181     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 182     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 183                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 184                                                          AllocFailStrategy::RETURN_NULL);
 185     void* aligned_addr     = align_up(real_malloc_addr, alignment);
 186     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 187            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 188            "JavaThread alignment code overflowed allocated storage");
 189     if (aligned_addr != real_malloc_addr) {
 190       log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 191                               p2i(real_malloc_addr),
 192                               p2i(aligned_addr));
 193     }
 194     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 195     return aligned_addr;
 196   } else {
 197     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 198                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 199   }
 200 }
 201 
 202 void Thread::operator delete(void* p) {
 203   if (UseBiasedLocking) {
 204     FreeHeap(((Thread*) p)->_real_malloc_address);
 205   } else {
 206     FreeHeap(p);
 207   }
 208 }
 209 
 210 void JavaThread::smr_delete() {
 211   if (_on_thread_list) {
 212     ThreadsSMRSupport::smr_delete(this);
 213   } else {
 214     delete this;
 215   }
 216 }
 217 
 218 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 219 // JavaThread
 220 
 221 
 222 Thread::Thread() {
 223   // stack and get_thread
 224   set_stack_base(NULL);
 225   set_stack_size(0);
 226   set_self_raw_id(0);
 227   set_lgrp_id(-1);
 228   DEBUG_ONLY(clear_suspendible_thread();)
 229 
 230   // allocated data structures
 231   set_osthread(NULL);
 232   set_resource_area(new (mtThread)ResourceArea());
 233   DEBUG_ONLY(_current_resource_mark = NULL;)
 234   set_handle_area(new (mtThread) HandleArea(NULL));
 235   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 236   set_active_handles(NULL);
 237   set_free_handle_block(NULL);
 238   set_last_handle_mark(NULL);
 239 
 240   _statistic_info.setStartTime(os::javaTimeMillis());
 241   _statistic_info.setDefineClassCount(0);
 242 
 243   // This initial value ==> never claimed.
 244   _oops_do_parity = 0;
 245   _threads_hazard_ptr = NULL;
 246   _threads_list_ptr = NULL;
 247   _nested_threads_hazard_ptr_cnt = 0;
 248   _rcu_counter = 0;
 249 
 250   // the handle mark links itself to last_handle_mark
 251   new HandleMark(this);
 252 
 253   // plain initialization
 254   debug_only(_owned_locks = NULL;)
 255   debug_only(_allow_allocation_count = 0;)
 256   NOT_PRODUCT(_allow_safepoint_count = 0;)
 257   NOT_PRODUCT(_skip_gcalot = false;)
 258   _jvmti_env_iteration_count = 0;
 259   set_allocated_bytes(0);
 260   _vm_operation_started_count = 0;
 261   _vm_operation_completed_count = 0;
 262   _current_pending_monitor = NULL;
 263   _current_pending_monitor_is_from_java = true;
 264   _current_waiting_monitor = NULL;
 265   _num_nested_signal = 0;
 266   omFreeList = NULL;
 267   omFreeCount = 0;
 268   omFreeProvision = 32;
 269   omInUseList = NULL;
 270   omInUseCount = 0;
 271 
 272 #ifdef ASSERT
 273   _visited_for_critical_count = false;
 274 #endif
 275 
 276   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
 277                          Monitor::_safepoint_check_sometimes);
 278   _suspend_flags = 0;
 279 
 280   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 281   _hashStateX = os::random();
 282   _hashStateY = 842502087;
 283   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 284   _hashStateW = 273326509;
 285 
 286   _OnTrap   = 0;
 287   _schedctl = NULL;
 288   _Stalled  = 0;
 289   _TypeTag  = 0x2BAD;
 290 
 291   // Many of the following fields are effectively final - immutable
 292   // Note that nascent threads can't use the Native Monitor-Mutex
 293   // construct until the _MutexEvent is initialized ...
 294   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 295   // we might instead use a stack of ParkEvents that we could provision on-demand.
 296   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 297   // and ::Release()
 298   _ParkEvent   = ParkEvent::Allocate(this);
 299   _SleepEvent  = ParkEvent::Allocate(this);
 300   _MutexEvent  = ParkEvent::Allocate(this);
 301   _MuxEvent    = ParkEvent::Allocate(this);
 302 
 303 #ifdef CHECK_UNHANDLED_OOPS
 304   if (CheckUnhandledOops) {
 305     _unhandled_oops = new UnhandledOops(this);
 306   }
 307 #endif // CHECK_UNHANDLED_OOPS
 308 #ifdef ASSERT
 309   if (UseBiasedLocking) {
 310     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 311     assert(this == _real_malloc_address ||
 312            this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
 313            "bug in forced alignment of thread objects");
 314   }
 315 #endif // ASSERT
 316 
 317   // Notify the barrier set that a thread is being created. Note that the
 318   // main thread is created before a barrier set is available. The call to
 319   // BarrierSet::on_thread_create() for the main thread is therefore deferred
 320   // until it calls BarrierSet::set_barrier_set().
 321   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 322   if (barrier_set != NULL) {
 323     barrier_set->on_thread_create(this);
 324   }
 325 }
 326 
 327 void Thread::initialize_thread_current() {
 328 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 329   assert(_thr_current == NULL, "Thread::current already initialized");
 330   _thr_current = this;
 331 #endif
 332   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 333   ThreadLocalStorage::set_thread(this);
 334   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 335 }
 336 
 337 void Thread::clear_thread_current() {
 338   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 339 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 340   _thr_current = NULL;
 341 #endif
 342   ThreadLocalStorage::set_thread(NULL);
 343 }
 344 
 345 void Thread::record_stack_base_and_size() {
 346   set_stack_base(os::current_stack_base());
 347   set_stack_size(os::current_stack_size());
 348   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 349   // in initialize_thread(). Without the adjustment, stack size is
 350   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 351   // So far, only Solaris has real implementation of initialize_thread().
 352   //
 353   // set up any platform-specific state.
 354   os::initialize_thread(this);
 355 
 356   // Set stack limits after thread is initialized.
 357   if (is_Java_thread()) {
 358     ((JavaThread*) this)->set_stack_overflow_limit();
 359     ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
 360   }
 361 #if INCLUDE_NMT
 362   // record thread's native stack, stack grows downward
 363   MemTracker::record_thread_stack(stack_end(), stack_size());
 364 #endif // INCLUDE_NMT
 365   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 366     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 367     os::current_thread_id(), p2i(stack_base() - stack_size()),
 368     p2i(stack_base()), stack_size()/1024);
 369 }
 370 
 371 
 372 Thread::~Thread() {
 373   JFR_ONLY(Jfr::on_thread_destruct(this);)
 374 
 375   // Notify the barrier set that a thread is being destroyed. Note that a barrier
 376   // set might not be available if we encountered errors during bootstrapping.
 377   BarrierSet* const barrier_set = BarrierSet::barrier_set();
 378   if (barrier_set != NULL) {
 379     barrier_set->on_thread_destroy(this);
 380   }
 381 
 382 
 383   // stack_base can be NULL if the thread is never started or exited before
 384   // record_stack_base_and_size called. Although, we would like to ensure
 385   // that all started threads do call record_stack_base_and_size(), there is
 386   // not proper way to enforce that.
 387 #if INCLUDE_NMT
 388   if (_stack_base != NULL) {
 389     MemTracker::release_thread_stack(stack_end(), stack_size());
 390 #ifdef ASSERT
 391     set_stack_base(NULL);
 392 #endif
 393   }
 394 #endif // INCLUDE_NMT
 395 
 396   // deallocate data structures
 397   delete resource_area();
 398   // since the handle marks are using the handle area, we have to deallocated the root
 399   // handle mark before deallocating the thread's handle area,
 400   assert(last_handle_mark() != NULL, "check we have an element");
 401   delete last_handle_mark();
 402   assert(last_handle_mark() == NULL, "check we have reached the end");
 403 
 404   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 405   // We NULL out the fields for good hygiene.
 406   ParkEvent::Release(_ParkEvent); _ParkEvent   = NULL;
 407   ParkEvent::Release(_SleepEvent); _SleepEvent  = NULL;
 408   ParkEvent::Release(_MutexEvent); _MutexEvent  = NULL;
 409   ParkEvent::Release(_MuxEvent); _MuxEvent    = NULL;
 410 
 411   delete handle_area();
 412   delete metadata_handles();
 413 
 414   // SR_handler uses this as a termination indicator -
 415   // needs to happen before os::free_thread()
 416   delete _SR_lock;
 417   _SR_lock = NULL;
 418 
 419   // osthread() can be NULL, if creation of thread failed.
 420   if (osthread() != NULL) os::free_thread(osthread());
 421 
 422   // clear Thread::current if thread is deleting itself.
 423   // Needed to ensure JNI correctly detects non-attached threads.
 424   if (this == Thread::current()) {
 425     clear_thread_current();
 426   }
 427 
 428   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 429 }
 430 
 431 // NOTE: dummy function for assertion purpose.
 432 void Thread::run() {
 433   ShouldNotReachHere();
 434 }
 435 
 436 #ifdef ASSERT
 437 // A JavaThread is considered "dangling" if it is not the current
 438 // thread, has been added the Threads list, the system is not at a
 439 // safepoint and the Thread is not "protected".
 440 //
 441 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 442   assert(!thread->is_Java_thread() || Thread::current() == thread ||
 443          !((JavaThread *) thread)->on_thread_list() ||
 444          SafepointSynchronize::is_at_safepoint() ||
 445          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
 446          "possibility of dangling Thread pointer");
 447 }
 448 #endif
 449 
 450 ThreadPriority Thread::get_priority(const Thread* const thread) {
 451   ThreadPriority priority;
 452   // Can return an error!
 453   (void)os::get_priority(thread, priority);
 454   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 455   return priority;
 456 }
 457 
 458 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 459   debug_only(check_for_dangling_thread_pointer(thread);)
 460   // Can return an error!
 461   (void)os::set_priority(thread, priority);
 462 }
 463 
 464 
 465 void Thread::start(Thread* thread) {
 466   // Start is different from resume in that its safety is guaranteed by context or
 467   // being called from a Java method synchronized on the Thread object.
 468   if (!DisableStartThread) {
 469     if (thread->is_Java_thread()) {
 470       // Initialize the thread state to RUNNABLE before starting this thread.
 471       // Can not set it after the thread started because we do not know the
 472       // exact thread state at that time. It could be in MONITOR_WAIT or
 473       // in SLEEPING or some other state.
 474       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 475                                           java_lang_Thread::RUNNABLE);
 476     }
 477     os::start_thread(thread);
 478   }
 479 }
 480 
 481 // Enqueue a VM_Operation to do the job for us - sometime later
 482 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 483   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 484   VMThread::execute(vm_stop);
 485 }
 486 
 487 
 488 // Check if an external suspend request has completed (or has been
 489 // cancelled). Returns true if the thread is externally suspended and
 490 // false otherwise.
 491 //
 492 // The bits parameter returns information about the code path through
 493 // the routine. Useful for debugging:
 494 //
 495 // set in is_ext_suspend_completed():
 496 // 0x00000001 - routine was entered
 497 // 0x00000010 - routine return false at end
 498 // 0x00000100 - thread exited (return false)
 499 // 0x00000200 - suspend request cancelled (return false)
 500 // 0x00000400 - thread suspended (return true)
 501 // 0x00001000 - thread is in a suspend equivalent state (return true)
 502 // 0x00002000 - thread is native and walkable (return true)
 503 // 0x00004000 - thread is native_trans and walkable (needed retry)
 504 //
 505 // set in wait_for_ext_suspend_completion():
 506 // 0x00010000 - routine was entered
 507 // 0x00020000 - suspend request cancelled before loop (return false)
 508 // 0x00040000 - thread suspended before loop (return true)
 509 // 0x00080000 - suspend request cancelled in loop (return false)
 510 // 0x00100000 - thread suspended in loop (return true)
 511 // 0x00200000 - suspend not completed during retry loop (return false)
 512 
 513 // Helper class for tracing suspend wait debug bits.
 514 //
 515 // 0x00000100 indicates that the target thread exited before it could
 516 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 517 // 0x00080000 each indicate a cancelled suspend request so they don't
 518 // count as wait failures either.
 519 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 520 
 521 class TraceSuspendDebugBits : public StackObj {
 522  private:
 523   JavaThread * jt;
 524   bool         is_wait;
 525   bool         called_by_wait;  // meaningful when !is_wait
 526   uint32_t *   bits;
 527 
 528  public:
 529   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 530                         uint32_t *_bits) {
 531     jt             = _jt;
 532     is_wait        = _is_wait;
 533     called_by_wait = _called_by_wait;
 534     bits           = _bits;
 535   }
 536 
 537   ~TraceSuspendDebugBits() {
 538     if (!is_wait) {
 539 #if 1
 540       // By default, don't trace bits for is_ext_suspend_completed() calls.
 541       // That trace is very chatty.
 542       return;
 543 #else
 544       if (!called_by_wait) {
 545         // If tracing for is_ext_suspend_completed() is enabled, then only
 546         // trace calls to it from wait_for_ext_suspend_completion()
 547         return;
 548       }
 549 #endif
 550     }
 551 
 552     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 553       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 554         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 555         ResourceMark rm;
 556 
 557         tty->print_cr(
 558                       "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 559                       jt->get_thread_name(), *bits);
 560 
 561         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 562       }
 563     }
 564   }
 565 };
 566 #undef DEBUG_FALSE_BITS
 567 
 568 
 569 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
 570                                           uint32_t *bits) {
 571   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 572 
 573   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 574   bool do_trans_retry;           // flag to force the retry
 575 
 576   *bits |= 0x00000001;
 577 
 578   do {
 579     do_trans_retry = false;
 580 
 581     if (is_exiting()) {
 582       // Thread is in the process of exiting. This is always checked
 583       // first to reduce the risk of dereferencing a freed JavaThread.
 584       *bits |= 0x00000100;
 585       return false;
 586     }
 587 
 588     if (!is_external_suspend()) {
 589       // Suspend request is cancelled. This is always checked before
 590       // is_ext_suspended() to reduce the risk of a rogue resume
 591       // confusing the thread that made the suspend request.
 592       *bits |= 0x00000200;
 593       return false;
 594     }
 595 
 596     if (is_ext_suspended()) {
 597       // thread is suspended
 598       *bits |= 0x00000400;
 599       return true;
 600     }
 601 
 602     // Now that we no longer do hard suspends of threads running
 603     // native code, the target thread can be changing thread state
 604     // while we are in this routine:
 605     //
 606     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 607     //
 608     // We save a copy of the thread state as observed at this moment
 609     // and make our decision about suspend completeness based on the
 610     // copy. This closes the race where the thread state is seen as
 611     // _thread_in_native_trans in the if-thread_blocked check, but is
 612     // seen as _thread_blocked in if-thread_in_native_trans check.
 613     JavaThreadState save_state = thread_state();
 614 
 615     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 616       // If the thread's state is _thread_blocked and this blocking
 617       // condition is known to be equivalent to a suspend, then we can
 618       // consider the thread to be externally suspended. This means that
 619       // the code that sets _thread_blocked has been modified to do
 620       // self-suspension if the blocking condition releases. We also
 621       // used to check for CONDVAR_WAIT here, but that is now covered by
 622       // the _thread_blocked with self-suspension check.
 623       //
 624       // Return true since we wouldn't be here unless there was still an
 625       // external suspend request.
 626       *bits |= 0x00001000;
 627       return true;
 628     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 629       // Threads running native code will self-suspend on native==>VM/Java
 630       // transitions. If its stack is walkable (should always be the case
 631       // unless this function is called before the actual java_suspend()
 632       // call), then the wait is done.
 633       *bits |= 0x00002000;
 634       return true;
 635     } else if (!called_by_wait && !did_trans_retry &&
 636                save_state == _thread_in_native_trans &&
 637                frame_anchor()->walkable()) {
 638       // The thread is transitioning from thread_in_native to another
 639       // thread state. check_safepoint_and_suspend_for_native_trans()
 640       // will force the thread to self-suspend. If it hasn't gotten
 641       // there yet we may have caught the thread in-between the native
 642       // code check above and the self-suspend. Lucky us. If we were
 643       // called by wait_for_ext_suspend_completion(), then it
 644       // will be doing the retries so we don't have to.
 645       //
 646       // Since we use the saved thread state in the if-statement above,
 647       // there is a chance that the thread has already transitioned to
 648       // _thread_blocked by the time we get here. In that case, we will
 649       // make a single unnecessary pass through the logic below. This
 650       // doesn't hurt anything since we still do the trans retry.
 651 
 652       *bits |= 0x00004000;
 653 
 654       // Once the thread leaves thread_in_native_trans for another
 655       // thread state, we break out of this retry loop. We shouldn't
 656       // need this flag to prevent us from getting back here, but
 657       // sometimes paranoia is good.
 658       did_trans_retry = true;
 659 
 660       // We wait for the thread to transition to a more usable state.
 661       for (int i = 1; i <= SuspendRetryCount; i++) {
 662         // We used to do an "os::yield_all(i)" call here with the intention
 663         // that yielding would increase on each retry. However, the parameter
 664         // is ignored on Linux which means the yield didn't scale up. Waiting
 665         // on the SR_lock below provides a much more predictable scale up for
 666         // the delay. It also provides a simple/direct point to check for any
 667         // safepoint requests from the VMThread
 668 
 669         // temporarily drops SR_lock while doing wait with safepoint check
 670         // (if we're a JavaThread - the WatcherThread can also call this)
 671         // and increase delay with each retry
 672         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 673 
 674         // check the actual thread state instead of what we saved above
 675         if (thread_state() != _thread_in_native_trans) {
 676           // the thread has transitioned to another thread state so
 677           // try all the checks (except this one) one more time.
 678           do_trans_retry = true;
 679           break;
 680         }
 681       } // end retry loop
 682 
 683 
 684     }
 685   } while (do_trans_retry);
 686 
 687   *bits |= 0x00000010;
 688   return false;
 689 }
 690 
 691 // Wait for an external suspend request to complete (or be cancelled).
 692 // Returns true if the thread is externally suspended and false otherwise.
 693 //
 694 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 695                                                  uint32_t *bits) {
 696   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 697                              false /* !called_by_wait */, bits);
 698 
 699   // local flag copies to minimize SR_lock hold time
 700   bool is_suspended;
 701   bool pending;
 702   uint32_t reset_bits;
 703 
 704   // set a marker so is_ext_suspend_completed() knows we are the caller
 705   *bits |= 0x00010000;
 706 
 707   // We use reset_bits to reinitialize the bits value at the top of
 708   // each retry loop. This allows the caller to make use of any
 709   // unused bits for their own marking purposes.
 710   reset_bits = *bits;
 711 
 712   {
 713     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 714     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 715                                             delay, bits);
 716     pending = is_external_suspend();
 717   }
 718   // must release SR_lock to allow suspension to complete
 719 
 720   if (!pending) {
 721     // A cancelled suspend request is the only false return from
 722     // is_ext_suspend_completed() that keeps us from entering the
 723     // retry loop.
 724     *bits |= 0x00020000;
 725     return false;
 726   }
 727 
 728   if (is_suspended) {
 729     *bits |= 0x00040000;
 730     return true;
 731   }
 732 
 733   for (int i = 1; i <= retries; i++) {
 734     *bits = reset_bits;  // reinit to only track last retry
 735 
 736     // We used to do an "os::yield_all(i)" call here with the intention
 737     // that yielding would increase on each retry. However, the parameter
 738     // is ignored on Linux which means the yield didn't scale up. Waiting
 739     // on the SR_lock below provides a much more predictable scale up for
 740     // the delay. It also provides a simple/direct point to check for any
 741     // safepoint requests from the VMThread
 742 
 743     {
 744       MutexLocker ml(SR_lock());
 745       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 746       // can also call this)  and increase delay with each retry
 747       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 748 
 749       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 750                                               delay, bits);
 751 
 752       // It is possible for the external suspend request to be cancelled
 753       // (by a resume) before the actual suspend operation is completed.
 754       // Refresh our local copy to see if we still need to wait.
 755       pending = is_external_suspend();
 756     }
 757 
 758     if (!pending) {
 759       // A cancelled suspend request is the only false return from
 760       // is_ext_suspend_completed() that keeps us from staying in the
 761       // retry loop.
 762       *bits |= 0x00080000;
 763       return false;
 764     }
 765 
 766     if (is_suspended) {
 767       *bits |= 0x00100000;
 768       return true;
 769     }
 770   } // end retry loop
 771 
 772   // thread did not suspend after all our retries
 773   *bits |= 0x00200000;
 774   return false;
 775 }
 776 
 777 // Called from API entry points which perform stack walking. If the
 778 // associated JavaThread is the current thread, then wait_for_suspend
 779 // is not used. Otherwise, it determines if we should wait for the
 780 // "other" thread to complete external suspension. (NOTE: in future
 781 // releases the suspension mechanism should be reimplemented so this
 782 // is not necessary.)
 783 //
 784 bool
 785 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
 786   if (this != JavaThread::current()) {
 787     // "other" threads require special handling.
 788     if (wait_for_suspend) {
 789       // We are allowed to wait for the external suspend to complete
 790       // so give the other thread a chance to get suspended.
 791       if (!wait_for_ext_suspend_completion(SuspendRetryCount,
 792                                            SuspendRetryDelay, bits)) {
 793         // Didn't make it so let the caller know.
 794         return false;
 795       }
 796     }
 797     // We aren't allowed to wait for the external suspend to complete
 798     // so if the other thread isn't externally suspended we need to
 799     // let the caller know.
 800     else if (!is_ext_suspend_completed_with_lock(bits)) {
 801       return false;
 802     }
 803   }
 804 
 805   return true;
 806 }
 807 
 808 #ifndef PRODUCT
 809 void JavaThread::record_jump(address target, address instr, const char* file,
 810                              int line) {
 811 
 812   // This should not need to be atomic as the only way for simultaneous
 813   // updates is via interrupts. Even then this should be rare or non-existent
 814   // and we don't care that much anyway.
 815 
 816   int index = _jmp_ring_index;
 817   _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
 818   _jmp_ring[index]._target = (intptr_t) target;
 819   _jmp_ring[index]._instruction = (intptr_t) instr;
 820   _jmp_ring[index]._file = file;
 821   _jmp_ring[index]._line = line;
 822 }
 823 #endif // PRODUCT
 824 
 825 void Thread::interrupt(Thread* thread) {
 826   debug_only(check_for_dangling_thread_pointer(thread);)
 827   os::interrupt(thread);
 828 }
 829 
 830 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 831   debug_only(check_for_dangling_thread_pointer(thread);)
 832   // Note:  If clear_interrupted==false, this simply fetches and
 833   // returns the value of the field osthread()->interrupted().
 834   return os::is_interrupted(thread, clear_interrupted);
 835 }
 836 
 837 
 838 // GC Support
 839 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 840   int thread_parity = _oops_do_parity;
 841   if (thread_parity != strong_roots_parity) {
 842     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 843     if (res == thread_parity) {
 844       return true;
 845     } else {
 846       guarantee(res == strong_roots_parity, "Or else what?");
 847       return false;
 848     }
 849   }
 850   return false;
 851 }
 852 
 853 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 854   active_handles()->oops_do(f);
 855   // Do oop for ThreadShadow
 856   f->do_oop((oop*)&_pending_exception);
 857   handle_area()->oops_do(f);
 858 
 859   if (MonitorInUseLists) {
 860     // When using thread local monitor lists, we scan them here,
 861     // and the remaining global monitors in ObjectSynchronizer::oops_do().
 862     ObjectSynchronizer::thread_local_used_oops_do(this, f);
 863   }
 864 }
 865 
 866 void Thread::metadata_handles_do(void f(Metadata*)) {
 867   // Only walk the Handles in Thread.
 868   if (metadata_handles() != NULL) {
 869     for (int i = 0; i< metadata_handles()->length(); i++) {
 870       f(metadata_handles()->at(i));
 871     }
 872   }
 873 }
 874 
 875 void Thread::print_on(outputStream* st, bool extended_thread_info) const {
 876   // get_priority assumes osthread initialized
 877   if (osthread() != NULL) {
 878     int os_prio;
 879     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 880       st->print("os_prio=%d ", os_prio);
 881     }
 882 
 883     st->print("cpu=%.2fms ",
 884               os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
 885               );
 886     st->print("elapsed=%.2fs ",
 887               _statistic_info.getElapsedTime() / 1000.0);
 888 
 889     if (is_Java_thread() && (PrintExtendedThreadInfo || extended_thread_info)) {
 890       jlong allocated_bytes = const_cast<Thread*>(this)->cooked_allocated_bytes();
 891       st->print("allocated=" JLONG_FORMAT "B ", allocated_bytes);
 892       st->print("defined_classes=" INT64_FORMAT " ", _statistic_info.getDefineClassCount());
 893     }
 894 
 895     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 896     osthread()->print_on(st);
 897   }
 898   ThreadsSMRSupport::print_info_on(this, st);
 899   st->print(" ");
 900   debug_only(if (WizardMode) print_owned_locks_on(st);)
 901 }
 902 
 903 // Thread::print_on_error() is called by fatal error handler. Don't use
 904 // any lock or allocate memory.
 905 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 906   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 907 
 908   if (is_VM_thread())                 { st->print("VMThread"); }
 909   else if (is_GC_task_thread())       { st->print("GCTaskThread"); }
 910   else if (is_Watcher_thread())       { st->print("WatcherThread"); }
 911   else if (is_ConcurrentGC_thread())  { st->print("ConcurrentGCThread"); }
 912   else                                { st->print("Thread"); }
 913 
 914   if (is_Named_thread()) {
 915     st->print(" \"%s\"", name());
 916   }
 917 
 918   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 919             p2i(stack_end()), p2i(stack_base()));
 920 
 921   if (osthread()) {
 922     st->print(" [id=%d]", osthread()->thread_id());
 923   }
 924 
 925   ThreadsSMRSupport::print_info_on(this, st);
 926 }
 927 
 928 void Thread::print_value_on(outputStream* st) const {
 929   if (is_Named_thread()) {
 930     st->print(" \"%s\" ", name());
 931   }
 932   st->print(INTPTR_FORMAT, p2i(this));   // print address
 933 }
 934 
 935 #ifdef ASSERT
 936 void Thread::print_owned_locks_on(outputStream* st) const {
 937   Monitor *cur = _owned_locks;
 938   if (cur == NULL) {
 939     st->print(" (no locks) ");
 940   } else {
 941     st->print_cr(" Locks owned:");
 942     while (cur) {
 943       cur->print_on(st);
 944       cur = cur->next();
 945     }
 946   }
 947 }
 948 
 949 static int ref_use_count  = 0;
 950 
 951 bool Thread::owns_locks_but_compiled_lock() const {
 952   for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 953     if (cur != Compile_lock) return true;
 954   }
 955   return false;
 956 }
 957 
 958 
 959 #endif
 960 
 961 #ifndef PRODUCT
 962 
 963 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
 964 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
 965 // no threads which allow_vm_block's are held
 966 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 967   // Check if current thread is allowed to block at a safepoint
 968   if (!(_allow_safepoint_count == 0)) {
 969     fatal("Possible safepoint reached by thread that does not allow it");
 970   }
 971   if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 972     fatal("LEAF method calling lock?");
 973   }
 974 
 975 #ifdef ASSERT
 976   if (potential_vm_operation && is_Java_thread()
 977       && !Universe::is_bootstrapping()) {
 978     // Make sure we do not hold any locks that the VM thread also uses.
 979     // This could potentially lead to deadlocks
 980     for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 981       // Threads_lock is special, since the safepoint synchronization will not start before this is
 982       // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 983       // since it is used to transfer control between JavaThreads and the VMThread
 984       // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
 985       if ((cur->allow_vm_block() &&
 986            cur != Threads_lock &&
 987            cur != Compile_lock &&               // Temporary: should not be necessary when we get separate compilation
 988            cur != VMOperationRequest_lock &&
 989            cur != VMOperationQueue_lock) ||
 990            cur->rank() == Mutex::special) {
 991         fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 992       }
 993     }
 994   }
 995 
 996   if (GCALotAtAllSafepoints) {
 997     // We could enter a safepoint here and thus have a gc
 998     InterfaceSupport::check_gc_alot();
 999   }
1000 #endif
1001 }
1002 #endif
1003 
1004 bool Thread::is_in_stack(address adr) const {
1005   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1006   address end = os::current_stack_pointer();
1007   // Allow non Java threads to call this without stack_base
1008   if (_stack_base == NULL) return true;
1009   if (stack_base() >= adr && adr >= end) return true;
1010 
1011   return false;
1012 }
1013 
1014 bool Thread::is_in_usable_stack(address adr) const {
1015   size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1016   size_t usable_stack_size = _stack_size - stack_guard_size;
1017 
1018   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1019 }
1020 
1021 
1022 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1023 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1024 // used for compilation in the future. If that change is made, the need for these methods
1025 // should be revisited, and they should be removed if possible.
1026 
1027 bool Thread::is_lock_owned(address adr) const {
1028   return on_local_stack(adr);
1029 }
1030 
1031 bool Thread::set_as_starting_thread() {
1032   // NOTE: this must be called inside the main thread.
1033   return os::create_main_thread((JavaThread*)this);
1034 }
1035 
1036 static void initialize_class(Symbol* class_name, TRAPS) {
1037   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1038   InstanceKlass::cast(klass)->initialize(CHECK);
1039 }
1040 
1041 
1042 // Creates the initial ThreadGroup
1043 static Handle create_initial_thread_group(TRAPS) {
1044   Handle system_instance = JavaCalls::construct_new_instance(
1045                             SystemDictionary::ThreadGroup_klass(),
1046                             vmSymbols::void_method_signature(),
1047                             CHECK_NH);
1048   Universe::set_system_thread_group(system_instance());
1049 
1050   Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1051   Handle main_instance = JavaCalls::construct_new_instance(
1052                             SystemDictionary::ThreadGroup_klass(),
1053                             vmSymbols::threadgroup_string_void_signature(),
1054                             system_instance,
1055                             string,
1056                             CHECK_NH);
1057   return main_instance;
1058 }
1059 
1060 // Creates the initial Thread
1061 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1062                                  TRAPS) {
1063   InstanceKlass* ik = SystemDictionary::Thread_klass();
1064   assert(ik->is_initialized(), "must be");
1065   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1066 
1067   // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1068   // constructor calls Thread.current(), which must be set here for the
1069   // initial thread.
1070   java_lang_Thread::set_thread(thread_oop(), thread);
1071   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1072   thread->set_threadObj(thread_oop());
1073 
1074   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1075 
1076   JavaValue result(T_VOID);
1077   JavaCalls::call_special(&result, thread_oop,
1078                           ik,
1079                           vmSymbols::object_initializer_name(),
1080                           vmSymbols::threadgroup_string_void_signature(),
1081                           thread_group,
1082                           string,
1083                           CHECK_NULL);
1084   return thread_oop();
1085 }
1086 
1087 char java_runtime_name[128] = "";
1088 char java_runtime_version[128] = "";
1089 
1090 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1091 static const char* get_java_runtime_name(TRAPS) {
1092   Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1093                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1094   fieldDescriptor fd;
1095   bool found = k != NULL &&
1096                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1097                                                         vmSymbols::string_signature(), &fd);
1098   if (found) {
1099     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1100     if (name_oop == NULL) {
1101       return NULL;
1102     }
1103     const char* name = java_lang_String::as_utf8_string(name_oop,
1104                                                         java_runtime_name,
1105                                                         sizeof(java_runtime_name));
1106     return name;
1107   } else {
1108     return NULL;
1109   }
1110 }
1111 
1112 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1113 static const char* get_java_runtime_version(TRAPS) {
1114   Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1115                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1116   fieldDescriptor fd;
1117   bool found = k != NULL &&
1118                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1119                                                         vmSymbols::string_signature(), &fd);
1120   if (found) {
1121     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1122     if (name_oop == NULL) {
1123       return NULL;
1124     }
1125     const char* name = java_lang_String::as_utf8_string(name_oop,
1126                                                         java_runtime_version,
1127                                                         sizeof(java_runtime_version));
1128     return name;
1129   } else {
1130     return NULL;
1131   }
1132 }
1133 
1134 // General purpose hook into Java code, run once when the VM is initialized.
1135 // The Java library method itself may be changed independently from the VM.
1136 static void call_postVMInitHook(TRAPS) {
1137   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1138   if (klass != NULL) {
1139     JavaValue result(T_VOID);
1140     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1141                            vmSymbols::void_method_signature(),
1142                            CHECK);
1143   }
1144 }
1145 
1146 static void reset_vm_info_property(TRAPS) {
1147   // the vm info string
1148   ResourceMark rm(THREAD);
1149   const char *vm_info = VM_Version::vm_info_string();
1150 
1151   // update the native system property first
1152   Arguments::PropertyList_update_value(Arguments::system_properties(), "java.vm.info", vm_info);
1153 
1154   // java.lang.System class
1155   Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1156 
1157   // setProperty arguments
1158   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1159   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1160 
1161   // return value
1162   JavaValue r(T_OBJECT);
1163 
1164   // public static String setProperty(String key, String value);
1165   JavaCalls::call_static(&r,
1166                          klass,
1167                          vmSymbols::setProperty_name(),
1168                          vmSymbols::string_string_string_signature(),
1169                          key_str,
1170                          value_str,
1171                          CHECK);
1172 }
1173 
1174 
1175 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1176                                     bool daemon, TRAPS) {
1177   assert(thread_group.not_null(), "thread group should be specified");
1178   assert(threadObj() == NULL, "should only create Java thread object once");
1179 
1180   InstanceKlass* ik = SystemDictionary::Thread_klass();
1181   assert(ik->is_initialized(), "must be");
1182   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1183 
1184   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1185   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1186   // constructor calls Thread.current(), which must be set here.
1187   java_lang_Thread::set_thread(thread_oop(), this);
1188   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1189   set_threadObj(thread_oop());
1190 
1191   JavaValue result(T_VOID);
1192   if (thread_name != NULL) {
1193     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1194     // Thread gets assigned specified name and null target
1195     JavaCalls::call_special(&result,
1196                             thread_oop,
1197                             ik,
1198                             vmSymbols::object_initializer_name(),
1199                             vmSymbols::threadgroup_string_void_signature(),
1200                             thread_group,
1201                             name,
1202                             THREAD);
1203   } else {
1204     // Thread gets assigned name "Thread-nnn" and null target
1205     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1206     JavaCalls::call_special(&result,
1207                             thread_oop,
1208                             ik,
1209                             vmSymbols::object_initializer_name(),
1210                             vmSymbols::threadgroup_runnable_void_signature(),
1211                             thread_group,
1212                             Handle(),
1213                             THREAD);
1214   }
1215 
1216 
1217   if (daemon) {
1218     java_lang_Thread::set_daemon(thread_oop());
1219   }
1220 
1221   if (HAS_PENDING_EXCEPTION) {
1222     return;
1223   }
1224 
1225   Klass* group =  SystemDictionary::ThreadGroup_klass();
1226   Handle threadObj(THREAD, this->threadObj());
1227 
1228   JavaCalls::call_special(&result,
1229                           thread_group,
1230                           group,
1231                           vmSymbols::add_method_name(),
1232                           vmSymbols::thread_void_signature(),
1233                           threadObj,          // Arg 1
1234                           THREAD);
1235 }
1236 
1237 // NamedThread --  non-JavaThread subclasses with multiple
1238 // uniquely named instances should derive from this.
1239 NamedThread::NamedThread() : Thread() {
1240   _name = NULL;
1241   _processed_thread = NULL;
1242   _gc_id = GCId::undefined();
1243 }
1244 
1245 NamedThread::~NamedThread() {
1246   if (_name != NULL) {
1247     FREE_C_HEAP_ARRAY(char, _name);
1248     _name = NULL;
1249   }
1250 }
1251 
1252 void NamedThread::set_name(const char* format, ...) {
1253   guarantee(_name == NULL, "Only get to set name once.");
1254   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1255   guarantee(_name != NULL, "alloc failure");
1256   va_list ap;
1257   va_start(ap, format);
1258   jio_vsnprintf(_name, max_name_len, format, ap);
1259   va_end(ap);
1260 }
1261 
1262 void NamedThread::initialize_named_thread() {
1263   set_native_thread_name(name());
1264 }
1265 
1266 void NamedThread::print_on(outputStream* st) const {
1267   st->print("\"%s\" ", name());
1268   Thread::print_on(st);
1269   st->cr();
1270 }
1271 
1272 
1273 // ======= WatcherThread ========
1274 
1275 // The watcher thread exists to simulate timer interrupts.  It should
1276 // be replaced by an abstraction over whatever native support for
1277 // timer interrupts exists on the platform.
1278 
1279 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1280 bool WatcherThread::_startable = false;
1281 volatile bool  WatcherThread::_should_terminate = false;
1282 
1283 WatcherThread::WatcherThread() : Thread() {
1284   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1285   if (os::create_thread(this, os::watcher_thread)) {
1286     _watcher_thread = this;
1287 
1288     // Set the watcher thread to the highest OS priority which should not be
1289     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1290     // is created. The only normal thread using this priority is the reference
1291     // handler thread, which runs for very short intervals only.
1292     // If the VMThread's priority is not lower than the WatcherThread profiling
1293     // will be inaccurate.
1294     os::set_priority(this, MaxPriority);
1295     if (!DisableStartThread) {
1296       os::start_thread(this);
1297     }
1298   }
1299 }
1300 
1301 int WatcherThread::sleep() const {
1302   // The WatcherThread does not participate in the safepoint protocol
1303   // for the PeriodicTask_lock because it is not a JavaThread.
1304   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1305 
1306   if (_should_terminate) {
1307     // check for termination before we do any housekeeping or wait
1308     return 0;  // we did not sleep.
1309   }
1310 
1311   // remaining will be zero if there are no tasks,
1312   // causing the WatcherThread to sleep until a task is
1313   // enrolled
1314   int remaining = PeriodicTask::time_to_wait();
1315   int time_slept = 0;
1316 
1317   // we expect this to timeout - we only ever get unparked when
1318   // we should terminate or when a new task has been enrolled
1319   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1320 
1321   jlong time_before_loop = os::javaTimeNanos();
1322 
1323   while (true) {
1324     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1325                                             remaining);
1326     jlong now = os::javaTimeNanos();
1327 
1328     if (remaining == 0) {
1329       // if we didn't have any tasks we could have waited for a long time
1330       // consider the time_slept zero and reset time_before_loop
1331       time_slept = 0;
1332       time_before_loop = now;
1333     } else {
1334       // need to recalculate since we might have new tasks in _tasks
1335       time_slept = (int) ((now - time_before_loop) / 1000000);
1336     }
1337 
1338     // Change to task list or spurious wakeup of some kind
1339     if (timedout || _should_terminate) {
1340       break;
1341     }
1342 
1343     remaining = PeriodicTask::time_to_wait();
1344     if (remaining == 0) {
1345       // Last task was just disenrolled so loop around and wait until
1346       // another task gets enrolled
1347       continue;
1348     }
1349 
1350     remaining -= time_slept;
1351     if (remaining <= 0) {
1352       break;
1353     }
1354   }
1355 
1356   return time_slept;
1357 }
1358 
1359 void WatcherThread::run() {
1360   assert(this == watcher_thread(), "just checking");
1361 
1362   this->record_stack_base_and_size();
1363   this->set_native_thread_name(this->name());
1364   this->set_active_handles(JNIHandleBlock::allocate_block());
1365   while (true) {
1366     assert(watcher_thread() == Thread::current(), "thread consistency check");
1367     assert(watcher_thread() == this, "thread consistency check");
1368 
1369     // Calculate how long it'll be until the next PeriodicTask work
1370     // should be done, and sleep that amount of time.
1371     int time_waited = sleep();
1372 
1373     if (VMError::is_error_reported()) {
1374       // A fatal error has happened, the error handler(VMError::report_and_die)
1375       // should abort JVM after creating an error log file. However in some
1376       // rare cases, the error handler itself might deadlock. Here periodically
1377       // check for error reporting timeouts, and if it happens, just proceed to
1378       // abort the VM.
1379 
1380       // This code is in WatcherThread because WatcherThread wakes up
1381       // periodically so the fatal error handler doesn't need to do anything;
1382       // also because the WatcherThread is less likely to crash than other
1383       // threads.
1384 
1385       for (;;) {
1386         // Note: we use naked sleep in this loop because we want to avoid using
1387         // any kind of VM infrastructure which may be broken at this point.
1388         if (VMError::check_timeout()) {
1389           // We hit error reporting timeout. Error reporting was interrupted and
1390           // will be wrapping things up now (closing files etc). Give it some more
1391           // time, then quit the VM.
1392           os::naked_short_sleep(200);
1393           // Print a message to stderr.
1394           fdStream err(defaultStream::output_fd());
1395           err.print_raw_cr("# [ timer expired, abort... ]");
1396           // skip atexit/vm_exit/vm_abort hooks
1397           os::die();
1398         }
1399 
1400         // Wait a second, then recheck for timeout.
1401         os::naked_short_sleep(999);
1402       }
1403     }
1404 
1405     if (_should_terminate) {
1406       // check for termination before posting the next tick
1407       break;
1408     }
1409 
1410     PeriodicTask::real_time_tick(time_waited);
1411   }
1412 
1413   // Signal that it is terminated
1414   {
1415     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1416     _watcher_thread = NULL;
1417     Terminator_lock->notify();
1418   }
1419 }
1420 
1421 void WatcherThread::start() {
1422   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1423 
1424   if (watcher_thread() == NULL && _startable) {
1425     _should_terminate = false;
1426     // Create the single instance of WatcherThread
1427     new WatcherThread();
1428   }
1429 }
1430 
1431 void WatcherThread::make_startable() {
1432   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1433   _startable = true;
1434 }
1435 
1436 void WatcherThread::stop() {
1437   {
1438     // Follow normal safepoint aware lock enter protocol since the
1439     // WatcherThread is stopped by another JavaThread.
1440     MutexLocker ml(PeriodicTask_lock);
1441     _should_terminate = true;
1442 
1443     WatcherThread* watcher = watcher_thread();
1444     if (watcher != NULL) {
1445       // unpark the WatcherThread so it can see that it should terminate
1446       watcher->unpark();
1447     }
1448   }
1449 
1450   MutexLocker mu(Terminator_lock);
1451 
1452   while (watcher_thread() != NULL) {
1453     // This wait should make safepoint checks, wait without a timeout,
1454     // and wait as a suspend-equivalent condition.
1455     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1456                           Mutex::_as_suspend_equivalent_flag);
1457   }
1458 }
1459 
1460 void WatcherThread::unpark() {
1461   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1462   PeriodicTask_lock->notify();
1463 }
1464 
1465 void WatcherThread::print_on(outputStream* st) const {
1466   st->print("\"%s\" ", name());
1467   Thread::print_on(st);
1468   st->cr();
1469 }
1470 
1471 // ======= JavaThread ========
1472 
1473 #if INCLUDE_JVMCI
1474 
1475 jlong* JavaThread::_jvmci_old_thread_counters;
1476 
1477 bool jvmci_counters_include(JavaThread* thread) {
1478   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1479 }
1480 
1481 void JavaThread::collect_counters(typeArrayOop array) {
1482   if (JVMCICounterSize > 0) {
1483     JavaThreadIteratorWithHandle jtiwh;
1484     for (int i = 0; i < array->length(); i++) {
1485       array->long_at_put(i, _jvmci_old_thread_counters[i]);
1486     }
1487     for (; JavaThread *tp = jtiwh.next(); ) {
1488       if (jvmci_counters_include(tp)) {
1489         for (int i = 0; i < array->length(); i++) {
1490           array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1491         }
1492       }
1493     }
1494   }
1495 }
1496 
1497 #endif // INCLUDE_JVMCI
1498 
1499 // A JavaThread is a normal Java thread
1500 
1501 void JavaThread::initialize() {
1502   // Initialize fields
1503 
1504   set_saved_exception_pc(NULL);
1505   set_threadObj(NULL);
1506   _anchor.clear();
1507   set_entry_point(NULL);
1508   set_jni_functions(jni_functions());
1509   set_callee_target(NULL);
1510   set_vm_result(NULL);
1511   set_vm_result_2(NULL);
1512   set_vframe_array_head(NULL);
1513   set_vframe_array_last(NULL);
1514   set_deferred_locals(NULL);
1515   set_deopt_mark(NULL);
1516   set_deopt_compiled_method(NULL);
1517   clear_must_deopt_id();
1518   set_monitor_chunks(NULL);
1519   set_next(NULL);
1520   _on_thread_list = false;
1521   set_thread_state(_thread_new);
1522   _terminated = _not_terminated;
1523   _privileged_stack_top = NULL;
1524   _array_for_gc = NULL;
1525   _suspend_equivalent = false;
1526   _in_deopt_handler = 0;
1527   _doing_unsafe_access = false;
1528   _stack_guard_state = stack_guard_unused;
1529 #if INCLUDE_JVMCI
1530   _pending_monitorenter = false;
1531   _pending_deoptimization = -1;
1532   _pending_failed_speculation = NULL;
1533   _pending_transfer_to_interpreter = false;
1534   _adjusting_comp_level = false;
1535   _jvmci._alternate_call_target = NULL;
1536   assert(_jvmci._implicit_exception_pc == NULL, "must be");
1537   if (JVMCICounterSize > 0) {
1538     _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1539     memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1540   } else {
1541     _jvmci_counters = NULL;
1542   }
1543 #endif // INCLUDE_JVMCI
1544   _reserved_stack_activation = NULL;  // stack base not known yet
1545   (void)const_cast<oop&>(_exception_oop = oop(NULL));
1546   _exception_pc  = 0;
1547   _exception_handler_pc = 0;
1548   _is_method_handle_return = 0;
1549   _jvmti_thread_state= NULL;
1550   _should_post_on_exceptions_flag = JNI_FALSE;
1551   _jvmti_get_loaded_classes_closure = NULL;
1552   _interp_only_mode    = 0;
1553   _special_runtime_exit_condition = _no_async_condition;
1554   _pending_async_exception = NULL;
1555   _thread_stat = NULL;
1556   _thread_stat = new ThreadStatistics();
1557   _blocked_on_compilation = false;
1558   _jni_active_critical = 0;
1559   _pending_jni_exception_check_fn = NULL;
1560   _do_not_unlock_if_synchronized = false;
1561   _cached_monitor_info = NULL;
1562   _parker = Parker::Allocate(this);
1563 
1564 #ifndef PRODUCT
1565   _jmp_ring_index = 0;
1566   for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1567     record_jump(NULL, NULL, NULL, 0);
1568   }
1569 #endif // PRODUCT
1570 
1571   // Setup safepoint state info for this thread
1572   ThreadSafepointState::create(this);
1573 
1574   debug_only(_java_call_counter = 0);
1575 
1576   // JVMTI PopFrame support
1577   _popframe_condition = popframe_inactive;
1578   _popframe_preserved_args = NULL;
1579   _popframe_preserved_args_size = 0;
1580   _frames_to_pop_failed_realloc = 0;
1581 
1582   if (SafepointMechanism::uses_thread_local_poll()) {
1583     SafepointMechanism::initialize_header(this);
1584   }
1585 
1586   pd_initialize();
1587 }
1588 
1589 JavaThread::JavaThread(bool is_attaching_via_jni) :
1590                        Thread() {
1591   initialize();
1592   if (is_attaching_via_jni) {
1593     _jni_attach_state = _attaching_via_jni;
1594   } else {
1595     _jni_attach_state = _not_attaching_via_jni;
1596   }
1597   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1598 }
1599 
1600 bool JavaThread::reguard_stack(address cur_sp) {
1601   if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1602       && _stack_guard_state != stack_guard_reserved_disabled) {
1603     return true; // Stack already guarded or guard pages not needed.
1604   }
1605 
1606   if (register_stack_overflow()) {
1607     // For those architectures which have separate register and
1608     // memory stacks, we must check the register stack to see if
1609     // it has overflowed.
1610     return false;
1611   }
1612 
1613   // Java code never executes within the yellow zone: the latter is only
1614   // there to provoke an exception during stack banging.  If java code
1615   // is executing there, either StackShadowPages should be larger, or
1616   // some exception code in c1, c2 or the interpreter isn't unwinding
1617   // when it should.
1618   guarantee(cur_sp > stack_reserved_zone_base(),
1619             "not enough space to reguard - increase StackShadowPages");
1620   if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1621     enable_stack_yellow_reserved_zone();
1622     if (reserved_stack_activation() != stack_base()) {
1623       set_reserved_stack_activation(stack_base());
1624     }
1625   } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1626     set_reserved_stack_activation(stack_base());
1627     enable_stack_reserved_zone();
1628   }
1629   return true;
1630 }
1631 
1632 bool JavaThread::reguard_stack(void) {
1633   return reguard_stack(os::current_stack_pointer());
1634 }
1635 
1636 
1637 void JavaThread::block_if_vm_exited() {
1638   if (_terminated == _vm_exited) {
1639     // _vm_exited is set at safepoint, and Threads_lock is never released
1640     // we will block here forever
1641     Threads_lock->lock_without_safepoint_check();
1642     ShouldNotReachHere();
1643   }
1644 }
1645 
1646 
1647 // Remove this ifdef when C1 is ported to the compiler interface.
1648 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1649 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1650 
1651 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1652                        Thread() {
1653   initialize();
1654   _jni_attach_state = _not_attaching_via_jni;
1655   set_entry_point(entry_point);
1656   // Create the native thread itself.
1657   // %note runtime_23
1658   os::ThreadType thr_type = os::java_thread;
1659   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1660                                                      os::java_thread;
1661   os::create_thread(this, thr_type, stack_sz);
1662   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1663   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1664   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1665   // the exception consists of creating the exception object & initializing it, initialization
1666   // will leave the VM via a JavaCall and then all locks must be unlocked).
1667   //
1668   // The thread is still suspended when we reach here. Thread must be explicit started
1669   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1670   // by calling Threads:add. The reason why this is not done here, is because the thread
1671   // object must be fully initialized (take a look at JVM_Start)
1672 }
1673 
1674 JavaThread::~JavaThread() {
1675 
1676   // JSR166 -- return the parker to the free list
1677   Parker::Release(_parker);
1678   _parker = NULL;
1679 
1680   // Free any remaining  previous UnrollBlock
1681   vframeArray* old_array = vframe_array_last();
1682 
1683   if (old_array != NULL) {
1684     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1685     old_array->set_unroll_block(NULL);
1686     delete old_info;
1687     delete old_array;
1688   }
1689 
1690   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1691   if (deferred != NULL) {
1692     // This can only happen if thread is destroyed before deoptimization occurs.
1693     assert(deferred->length() != 0, "empty array!");
1694     do {
1695       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1696       deferred->remove_at(0);
1697       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1698       delete dlv;
1699     } while (deferred->length() != 0);
1700     delete deferred;
1701   }
1702 
1703   // All Java related clean up happens in exit
1704   ThreadSafepointState::destroy(this);
1705   if (_thread_stat != NULL) delete _thread_stat;
1706 
1707 #if INCLUDE_JVMCI
1708   if (JVMCICounterSize > 0) {
1709     if (jvmci_counters_include(this)) {
1710       for (int i = 0; i < JVMCICounterSize; i++) {
1711         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1712       }
1713     }
1714     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1715   }
1716 #endif // INCLUDE_JVMCI
1717 }
1718 
1719 
1720 // The first routine called by a new Java thread
1721 void JavaThread::run() {
1722   // initialize thread-local alloc buffer related fields
1723   this->initialize_tlab();
1724 
1725   // used to test validity of stack trace backs
1726   this->record_base_of_stack_pointer();
1727 
1728   // Record real stack base and size.
1729   this->record_stack_base_and_size();
1730 
1731   this->create_stack_guard_pages();
1732 
1733   this->cache_global_variables();
1734 
1735   // Thread is now sufficient initialized to be handled by the safepoint code as being
1736   // in the VM. Change thread state from _thread_new to _thread_in_vm
1737   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1738 
1739   assert(JavaThread::current() == this, "sanity check");
1740   assert(!Thread::current()->owns_locks(), "sanity check");
1741 
1742   DTRACE_THREAD_PROBE(start, this);
1743 
1744   // This operation might block. We call that after all safepoint checks for a new thread has
1745   // been completed.
1746   this->set_active_handles(JNIHandleBlock::allocate_block());
1747 
1748   if (JvmtiExport::should_post_thread_life()) {
1749     JvmtiExport::post_thread_start(this);
1750   }
1751 
1752   EventThreadStart event;
1753   if (event.should_commit()) {
1754     event.set_thread(JFR_THREAD_ID(this));
1755     event.commit();
1756   }
1757 
1758   // We call another function to do the rest so we are sure that the stack addresses used
1759   // from there will be lower than the stack base just computed
1760   thread_main_inner();
1761 
1762   // Note, thread is no longer valid at this point!
1763 }
1764 
1765 
1766 void JavaThread::thread_main_inner() {
1767   assert(JavaThread::current() == this, "sanity check");
1768   assert(this->threadObj() != NULL, "just checking");
1769 
1770   // Execute thread entry point unless this thread has a pending exception
1771   // or has been stopped before starting.
1772   // Note: Due to JVM_StopThread we can have pending exceptions already!
1773   if (!this->has_pending_exception() &&
1774       !java_lang_Thread::is_stillborn(this->threadObj())) {
1775     {
1776       ResourceMark rm(this);
1777       this->set_native_thread_name(this->get_thread_name());
1778     }
1779     HandleMark hm(this);
1780     this->entry_point()(this, this);
1781   }
1782 
1783   DTRACE_THREAD_PROBE(stop, this);
1784 
1785   this->exit(false);
1786   this->smr_delete();
1787 }
1788 
1789 
1790 static void ensure_join(JavaThread* thread) {
1791   // We do not need to grab the Threads_lock, since we are operating on ourself.
1792   Handle threadObj(thread, thread->threadObj());
1793   assert(threadObj.not_null(), "java thread object must exist");
1794   ObjectLocker lock(threadObj, thread);
1795   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1796   thread->clear_pending_exception();
1797   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1798   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1799   // Clear the native thread instance - this makes isAlive return false and allows the join()
1800   // to complete once we've done the notify_all below
1801   java_lang_Thread::set_thread(threadObj(), NULL);
1802   lock.notify_all(thread);
1803   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1804   thread->clear_pending_exception();
1805 }
1806 
1807 
1808 // For any new cleanup additions, please check to see if they need to be applied to
1809 // cleanup_failed_attach_current_thread as well.
1810 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1811   assert(this == JavaThread::current(), "thread consistency check");
1812 
1813   elapsedTimer _timer_exit_phase1;
1814   elapsedTimer _timer_exit_phase2;
1815   elapsedTimer _timer_exit_phase3;
1816   elapsedTimer _timer_exit_phase4;
1817 
1818   if (log_is_enabled(Debug, os, thread, timer)) {
1819     _timer_exit_phase1.start();
1820   }
1821 
1822   HandleMark hm(this);
1823   Handle uncaught_exception(this, this->pending_exception());
1824   this->clear_pending_exception();
1825   Handle threadObj(this, this->threadObj());
1826   assert(threadObj.not_null(), "Java thread object should be created");
1827 
1828   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1829   {
1830     EXCEPTION_MARK;
1831 
1832     CLEAR_PENDING_EXCEPTION;
1833   }
1834   if (!destroy_vm) {
1835     if (uncaught_exception.not_null()) {
1836       EXCEPTION_MARK;
1837       // Call method Thread.dispatchUncaughtException().
1838       Klass* thread_klass = SystemDictionary::Thread_klass();
1839       JavaValue result(T_VOID);
1840       JavaCalls::call_virtual(&result,
1841                               threadObj, thread_klass,
1842                               vmSymbols::dispatchUncaughtException_name(),
1843                               vmSymbols::throwable_void_signature(),
1844                               uncaught_exception,
1845                               THREAD);
1846       if (HAS_PENDING_EXCEPTION) {
1847         ResourceMark rm(this);
1848         jio_fprintf(defaultStream::error_stream(),
1849                     "\nException: %s thrown from the UncaughtExceptionHandler"
1850                     " in thread \"%s\"\n",
1851                     pending_exception()->klass()->external_name(),
1852                     get_thread_name());
1853         CLEAR_PENDING_EXCEPTION;
1854       }
1855     }
1856 
1857     // Called before the java thread exit since we want to read info
1858     // from java_lang_Thread object
1859     EventThreadEnd event;
1860     if (event.should_commit()) {
1861       event.set_thread(JFR_THREAD_ID(this));
1862       event.commit();
1863     }
1864 
1865     // Call after last event on thread
1866     JFR_ONLY(Jfr::on_thread_exit(this);)
1867 
1868     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1869     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1870     // is deprecated anyhow.
1871     if (!is_Compiler_thread()) {
1872       int count = 3;
1873       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1874         EXCEPTION_MARK;
1875         JavaValue result(T_VOID);
1876         Klass* thread_klass = SystemDictionary::Thread_klass();
1877         JavaCalls::call_virtual(&result,
1878                                 threadObj, thread_klass,
1879                                 vmSymbols::exit_method_name(),
1880                                 vmSymbols::void_method_signature(),
1881                                 THREAD);
1882         CLEAR_PENDING_EXCEPTION;
1883       }
1884     }
1885     // notify JVMTI
1886     if (JvmtiExport::should_post_thread_life()) {
1887       JvmtiExport::post_thread_end(this);
1888     }
1889 
1890     // We have notified the agents that we are exiting, before we go on,
1891     // we must check for a pending external suspend request and honor it
1892     // in order to not surprise the thread that made the suspend request.
1893     while (true) {
1894       {
1895         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1896         if (!is_external_suspend()) {
1897           set_terminated(_thread_exiting);
1898           ThreadService::current_thread_exiting(this);
1899           break;
1900         }
1901         // Implied else:
1902         // Things get a little tricky here. We have a pending external
1903         // suspend request, but we are holding the SR_lock so we
1904         // can't just self-suspend. So we temporarily drop the lock
1905         // and then self-suspend.
1906       }
1907 
1908       ThreadBlockInVM tbivm(this);
1909       java_suspend_self();
1910 
1911       // We're done with this suspend request, but we have to loop around
1912       // and check again. Eventually we will get SR_lock without a pending
1913       // external suspend request and will be able to mark ourselves as
1914       // exiting.
1915     }
1916     // no more external suspends are allowed at this point
1917   } else {
1918     // before_exit() has already posted JVMTI THREAD_END events
1919   }
1920 
1921   if (log_is_enabled(Debug, os, thread, timer)) {
1922     _timer_exit_phase1.stop();
1923     _timer_exit_phase2.start();
1924   }
1925   // Notify waiters on thread object. This has to be done after exit() is called
1926   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1927   // group should have the destroyed bit set before waiters are notified).
1928   ensure_join(this);
1929   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1930 
1931   if (log_is_enabled(Debug, os, thread, timer)) {
1932     _timer_exit_phase2.stop();
1933     _timer_exit_phase3.start();
1934   }
1935   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1936   // held by this thread must be released. The spec does not distinguish
1937   // between JNI-acquired and regular Java monitors. We can only see
1938   // regular Java monitors here if monitor enter-exit matching is broken.
1939   //
1940   // Optionally release any monitors for regular JavaThread exits. This
1941   // is provided as a work around for any bugs in monitor enter-exit
1942   // matching. This can be expensive so it is not enabled by default.
1943   //
1944   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1945   // ObjectSynchronizer::release_monitors_owned_by_thread().
1946   if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1947     // Sanity check even though JNI DetachCurrentThread() would have
1948     // returned JNI_ERR if there was a Java frame. JavaThread exit
1949     // should be done executing Java code by the time we get here.
1950     assert(!this->has_last_Java_frame(),
1951            "should not have a Java frame when detaching or exiting");
1952     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1953     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1954   }
1955 
1956   // These things needs to be done while we are still a Java Thread. Make sure that thread
1957   // is in a consistent state, in case GC happens
1958   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1959 
1960   if (active_handles() != NULL) {
1961     JNIHandleBlock* block = active_handles();
1962     set_active_handles(NULL);
1963     JNIHandleBlock::release_block(block);
1964   }
1965 
1966   if (free_handle_block() != NULL) {
1967     JNIHandleBlock* block = free_handle_block();
1968     set_free_handle_block(NULL);
1969     JNIHandleBlock::release_block(block);
1970   }
1971 
1972   // These have to be removed while this is still a valid thread.
1973   remove_stack_guard_pages();
1974 
1975   if (UseTLAB) {
1976     tlab().make_parsable(true);  // retire TLAB
1977   }
1978 
1979   if (JvmtiEnv::environments_might_exist()) {
1980     JvmtiExport::cleanup_thread(this);
1981   }
1982 
1983   // We must flush any deferred card marks and other various GC barrier
1984   // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
1985   // before removing a thread from the list of active threads.
1986   BarrierSet::barrier_set()->on_thread_detach(this);
1987 
1988   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1989     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1990     os::current_thread_id());
1991 
1992   if (log_is_enabled(Debug, os, thread, timer)) {
1993     _timer_exit_phase3.stop();
1994     _timer_exit_phase4.start();
1995   }
1996   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1997   Threads::remove(this);
1998 
1999   if (log_is_enabled(Debug, os, thread, timer)) {
2000     _timer_exit_phase4.stop();
2001     ResourceMark rm(this);
2002     log_debug(os, thread, timer)("name='%s'"
2003                                  ", exit-phase1=" JLONG_FORMAT
2004                                  ", exit-phase2=" JLONG_FORMAT
2005                                  ", exit-phase3=" JLONG_FORMAT
2006                                  ", exit-phase4=" JLONG_FORMAT,
2007                                  get_thread_name(),
2008                                  _timer_exit_phase1.milliseconds(),
2009                                  _timer_exit_phase2.milliseconds(),
2010                                  _timer_exit_phase3.milliseconds(),
2011                                  _timer_exit_phase4.milliseconds());
2012   }
2013 }
2014 
2015 void JavaThread::cleanup_failed_attach_current_thread() {
2016   if (active_handles() != NULL) {
2017     JNIHandleBlock* block = active_handles();
2018     set_active_handles(NULL);
2019     JNIHandleBlock::release_block(block);
2020   }
2021 
2022   if (free_handle_block() != NULL) {
2023     JNIHandleBlock* block = free_handle_block();
2024     set_free_handle_block(NULL);
2025     JNIHandleBlock::release_block(block);
2026   }
2027 
2028   // These have to be removed while this is still a valid thread.
2029   remove_stack_guard_pages();
2030 
2031   if (UseTLAB) {
2032     tlab().make_parsable(true);  // retire TLAB, if any
2033   }
2034 
2035   BarrierSet::barrier_set()->on_thread_detach(this);
2036 
2037   Threads::remove(this);
2038   this->smr_delete();
2039 }
2040 
2041 JavaThread* JavaThread::active() {
2042   Thread* thread = Thread::current();
2043   if (thread->is_Java_thread()) {
2044     return (JavaThread*) thread;
2045   } else {
2046     assert(thread->is_VM_thread(), "this must be a vm thread");
2047     VM_Operation* op = ((VMThread*) thread)->vm_operation();
2048     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2049     assert(ret->is_Java_thread(), "must be a Java thread");
2050     return ret;
2051   }
2052 }
2053 
2054 bool JavaThread::is_lock_owned(address adr) const {
2055   if (Thread::is_lock_owned(adr)) return true;
2056 
2057   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2058     if (chunk->contains(adr)) return true;
2059   }
2060 
2061   return false;
2062 }
2063 
2064 
2065 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2066   chunk->set_next(monitor_chunks());
2067   set_monitor_chunks(chunk);
2068 }
2069 
2070 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2071   guarantee(monitor_chunks() != NULL, "must be non empty");
2072   if (monitor_chunks() == chunk) {
2073     set_monitor_chunks(chunk->next());
2074   } else {
2075     MonitorChunk* prev = monitor_chunks();
2076     while (prev->next() != chunk) prev = prev->next();
2077     prev->set_next(chunk->next());
2078   }
2079 }
2080 
2081 // JVM support.
2082 
2083 // Note: this function shouldn't block if it's called in
2084 // _thread_in_native_trans state (such as from
2085 // check_special_condition_for_native_trans()).
2086 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2087 
2088   if (has_last_Java_frame() && has_async_condition()) {
2089     // If we are at a polling page safepoint (not a poll return)
2090     // then we must defer async exception because live registers
2091     // will be clobbered by the exception path. Poll return is
2092     // ok because the call we a returning from already collides
2093     // with exception handling registers and so there is no issue.
2094     // (The exception handling path kills call result registers but
2095     //  this is ok since the exception kills the result anyway).
2096 
2097     if (is_at_poll_safepoint()) {
2098       // if the code we are returning to has deoptimized we must defer
2099       // the exception otherwise live registers get clobbered on the
2100       // exception path before deoptimization is able to retrieve them.
2101       //
2102       RegisterMap map(this, false);
2103       frame caller_fr = last_frame().sender(&map);
2104       assert(caller_fr.is_compiled_frame(), "what?");
2105       if (caller_fr.is_deoptimized_frame()) {
2106         log_info(exceptions)("deferred async exception at compiled safepoint");
2107         return;
2108       }
2109     }
2110   }
2111 
2112   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2113   if (condition == _no_async_condition) {
2114     // Conditions have changed since has_special_runtime_exit_condition()
2115     // was called:
2116     // - if we were here only because of an external suspend request,
2117     //   then that was taken care of above (or cancelled) so we are done
2118     // - if we were here because of another async request, then it has
2119     //   been cleared between the has_special_runtime_exit_condition()
2120     //   and now so again we are done
2121     return;
2122   }
2123 
2124   // Check for pending async. exception
2125   if (_pending_async_exception != NULL) {
2126     // Only overwrite an already pending exception, if it is not a threadDeath.
2127     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2128 
2129       // We cannot call Exceptions::_throw(...) here because we cannot block
2130       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2131 
2132       LogTarget(Info, exceptions) lt;
2133       if (lt.is_enabled()) {
2134         ResourceMark rm;
2135         LogStream ls(lt);
2136         ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2137           if (has_last_Java_frame()) {
2138             frame f = last_frame();
2139            ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2140           }
2141         ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2142       }
2143       _pending_async_exception = NULL;
2144       clear_has_async_exception();
2145     }
2146   }
2147 
2148   if (check_unsafe_error &&
2149       condition == _async_unsafe_access_error && !has_pending_exception()) {
2150     condition = _no_async_condition;  // done
2151     switch (thread_state()) {
2152     case _thread_in_vm: {
2153       JavaThread* THREAD = this;
2154       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2155     }
2156     case _thread_in_native: {
2157       ThreadInVMfromNative tiv(this);
2158       JavaThread* THREAD = this;
2159       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2160     }
2161     case _thread_in_Java: {
2162       ThreadInVMfromJava tiv(this);
2163       JavaThread* THREAD = this;
2164       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2165     }
2166     default:
2167       ShouldNotReachHere();
2168     }
2169   }
2170 
2171   assert(condition == _no_async_condition || has_pending_exception() ||
2172          (!check_unsafe_error && condition == _async_unsafe_access_error),
2173          "must have handled the async condition, if no exception");
2174 }
2175 
2176 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2177   //
2178   // Check for pending external suspend. Internal suspend requests do
2179   // not use handle_special_runtime_exit_condition().
2180   // If JNIEnv proxies are allowed, don't self-suspend if the target
2181   // thread is not the current thread. In older versions of jdbx, jdbx
2182   // threads could call into the VM with another thread's JNIEnv so we
2183   // can be here operating on behalf of a suspended thread (4432884).
2184   bool do_self_suspend = is_external_suspend_with_lock();
2185   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2186     //
2187     // Because thread is external suspended the safepoint code will count
2188     // thread as at a safepoint. This can be odd because we can be here
2189     // as _thread_in_Java which would normally transition to _thread_blocked
2190     // at a safepoint. We would like to mark the thread as _thread_blocked
2191     // before calling java_suspend_self like all other callers of it but
2192     // we must then observe proper safepoint protocol. (We can't leave
2193     // _thread_blocked with a safepoint in progress). However we can be
2194     // here as _thread_in_native_trans so we can't use a normal transition
2195     // constructor/destructor pair because they assert on that type of
2196     // transition. We could do something like:
2197     //
2198     // JavaThreadState state = thread_state();
2199     // set_thread_state(_thread_in_vm);
2200     // {
2201     //   ThreadBlockInVM tbivm(this);
2202     //   java_suspend_self()
2203     // }
2204     // set_thread_state(_thread_in_vm_trans);
2205     // if (safepoint) block;
2206     // set_thread_state(state);
2207     //
2208     // but that is pretty messy. Instead we just go with the way the
2209     // code has worked before and note that this is the only path to
2210     // java_suspend_self that doesn't put the thread in _thread_blocked
2211     // mode.
2212 
2213     frame_anchor()->make_walkable(this);
2214     java_suspend_self();
2215 
2216     // We might be here for reasons in addition to the self-suspend request
2217     // so check for other async requests.
2218   }
2219 
2220   if (check_asyncs) {
2221     check_and_handle_async_exceptions();
2222   }
2223 
2224   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2225 }
2226 
2227 void JavaThread::send_thread_stop(oop java_throwable)  {
2228   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2229   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2230   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2231 
2232   // Do not throw asynchronous exceptions against the compiler thread
2233   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2234   if (!can_call_java()) return;
2235 
2236   {
2237     // Actually throw the Throwable against the target Thread - however
2238     // only if there is no thread death exception installed already.
2239     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2240       // If the topmost frame is a runtime stub, then we are calling into
2241       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2242       // must deoptimize the caller before continuing, as the compiled  exception handler table
2243       // may not be valid
2244       if (has_last_Java_frame()) {
2245         frame f = last_frame();
2246         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2247           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2248           RegisterMap reg_map(this, UseBiasedLocking);
2249           frame compiled_frame = f.sender(&reg_map);
2250           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2251             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2252           }
2253         }
2254       }
2255 
2256       // Set async. pending exception in thread.
2257       set_pending_async_exception(java_throwable);
2258 
2259       if (log_is_enabled(Info, exceptions)) {
2260          ResourceMark rm;
2261         log_info(exceptions)("Pending Async. exception installed of type: %s",
2262                              InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2263       }
2264       // for AbortVMOnException flag
2265       Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2266     }
2267   }
2268 
2269 
2270   // Interrupt thread so it will wake up from a potential wait()
2271   Thread::interrupt(this);
2272 }
2273 
2274 // External suspension mechanism.
2275 //
2276 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2277 // to any VM_locks and it is at a transition
2278 // Self-suspension will happen on the transition out of the vm.
2279 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2280 //
2281 // Guarantees on return:
2282 //   + Target thread will not execute any new bytecode (that's why we need to
2283 //     force a safepoint)
2284 //   + Target thread will not enter any new monitors
2285 //
2286 void JavaThread::java_suspend() {
2287   ThreadsListHandle tlh;
2288   if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2289     return;
2290   }
2291 
2292   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2293     if (!is_external_suspend()) {
2294       // a racing resume has cancelled us; bail out now
2295       return;
2296     }
2297 
2298     // suspend is done
2299     uint32_t debug_bits = 0;
2300     // Warning: is_ext_suspend_completed() may temporarily drop the
2301     // SR_lock to allow the thread to reach a stable thread state if
2302     // it is currently in a transient thread state.
2303     if (is_ext_suspend_completed(false /* !called_by_wait */,
2304                                  SuspendRetryDelay, &debug_bits)) {
2305       return;
2306     }
2307   }
2308 
2309   VM_ThreadSuspend vm_suspend;
2310   VMThread::execute(&vm_suspend);
2311 }
2312 
2313 // Part II of external suspension.
2314 // A JavaThread self suspends when it detects a pending external suspend
2315 // request. This is usually on transitions. It is also done in places
2316 // where continuing to the next transition would surprise the caller,
2317 // e.g., monitor entry.
2318 //
2319 // Returns the number of times that the thread self-suspended.
2320 //
2321 // Note: DO NOT call java_suspend_self() when you just want to block current
2322 //       thread. java_suspend_self() is the second stage of cooperative
2323 //       suspension for external suspend requests and should only be used
2324 //       to complete an external suspend request.
2325 //
2326 int JavaThread::java_suspend_self() {
2327   int ret = 0;
2328 
2329   // we are in the process of exiting so don't suspend
2330   if (is_exiting()) {
2331     clear_external_suspend();
2332     return ret;
2333   }
2334 
2335   assert(_anchor.walkable() ||
2336          (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2337          "must have walkable stack");
2338 
2339   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2340 
2341   assert(!this->is_ext_suspended(),
2342          "a thread trying to self-suspend should not already be suspended");
2343 
2344   if (this->is_suspend_equivalent()) {
2345     // If we are self-suspending as a result of the lifting of a
2346     // suspend equivalent condition, then the suspend_equivalent
2347     // flag is not cleared until we set the ext_suspended flag so
2348     // that wait_for_ext_suspend_completion() returns consistent
2349     // results.
2350     this->clear_suspend_equivalent();
2351   }
2352 
2353   // A racing resume may have cancelled us before we grabbed SR_lock
2354   // above. Or another external suspend request could be waiting for us
2355   // by the time we return from SR_lock()->wait(). The thread
2356   // that requested the suspension may already be trying to walk our
2357   // stack and if we return now, we can change the stack out from under
2358   // it. This would be a "bad thing (TM)" and cause the stack walker
2359   // to crash. We stay self-suspended until there are no more pending
2360   // external suspend requests.
2361   while (is_external_suspend()) {
2362     ret++;
2363     this->set_ext_suspended();
2364 
2365     // _ext_suspended flag is cleared by java_resume()
2366     while (is_ext_suspended()) {
2367       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2368     }
2369   }
2370 
2371   return ret;
2372 }
2373 
2374 #ifdef ASSERT
2375 // Verify the JavaThread has not yet been published in the Threads::list, and
2376 // hence doesn't need protection from concurrent access at this stage.
2377 void JavaThread::verify_not_published() {
2378   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2379   // since an unpublished JavaThread doesn't participate in the
2380   // Thread-SMR protocol for keeping a ThreadsList alive.
2381   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2382 }
2383 #endif
2384 
2385 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2386 // progress or when _suspend_flags is non-zero.
2387 // Current thread needs to self-suspend if there is a suspend request and/or
2388 // block if a safepoint is in progress.
2389 // Async exception ISN'T checked.
2390 // Note only the ThreadInVMfromNative transition can call this function
2391 // directly and when thread state is _thread_in_native_trans
2392 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2393   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2394 
2395   JavaThread *curJT = JavaThread::current();
2396   bool do_self_suspend = thread->is_external_suspend();
2397 
2398   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2399 
2400   // If JNIEnv proxies are allowed, don't self-suspend if the target
2401   // thread is not the current thread. In older versions of jdbx, jdbx
2402   // threads could call into the VM with another thread's JNIEnv so we
2403   // can be here operating on behalf of a suspended thread (4432884).
2404   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2405     JavaThreadState state = thread->thread_state();
2406 
2407     // We mark this thread_blocked state as a suspend-equivalent so
2408     // that a caller to is_ext_suspend_completed() won't be confused.
2409     // The suspend-equivalent state is cleared by java_suspend_self().
2410     thread->set_suspend_equivalent();
2411 
2412     // If the safepoint code sees the _thread_in_native_trans state, it will
2413     // wait until the thread changes to other thread state. There is no
2414     // guarantee on how soon we can obtain the SR_lock and complete the
2415     // self-suspend request. It would be a bad idea to let safepoint wait for
2416     // too long. Temporarily change the state to _thread_blocked to
2417     // let the VM thread know that this thread is ready for GC. The problem
2418     // of changing thread state is that safepoint could happen just after
2419     // java_suspend_self() returns after being resumed, and VM thread will
2420     // see the _thread_blocked state. We must check for safepoint
2421     // after restoring the state and make sure we won't leave while a safepoint
2422     // is in progress.
2423     thread->set_thread_state(_thread_blocked);
2424     thread->java_suspend_self();
2425     thread->set_thread_state(state);
2426 
2427     InterfaceSupport::serialize_thread_state_with_handler(thread);
2428   }
2429 
2430   SafepointMechanism::block_if_requested(curJT);
2431 
2432   if (thread->is_deopt_suspend()) {
2433     thread->clear_deopt_suspend();
2434     RegisterMap map(thread, false);
2435     frame f = thread->last_frame();
2436     while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2437       f = f.sender(&map);
2438     }
2439     if (f.id() == thread->must_deopt_id()) {
2440       thread->clear_must_deopt_id();
2441       f.deoptimize(thread);
2442     } else {
2443       fatal("missed deoptimization!");
2444     }
2445   }
2446 
2447   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2448 }
2449 
2450 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2451 // progress or when _suspend_flags is non-zero.
2452 // Current thread needs to self-suspend if there is a suspend request and/or
2453 // block if a safepoint is in progress.
2454 // Also check for pending async exception (not including unsafe access error).
2455 // Note only the native==>VM/Java barriers can call this function and when
2456 // thread state is _thread_in_native_trans.
2457 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2458   check_safepoint_and_suspend_for_native_trans(thread);
2459 
2460   if (thread->has_async_exception()) {
2461     // We are in _thread_in_native_trans state, don't handle unsafe
2462     // access error since that may block.
2463     thread->check_and_handle_async_exceptions(false);
2464   }
2465 }
2466 
2467 // This is a variant of the normal
2468 // check_special_condition_for_native_trans with slightly different
2469 // semantics for use by critical native wrappers.  It does all the
2470 // normal checks but also performs the transition back into
2471 // thread_in_Java state.  This is required so that critical natives
2472 // can potentially block and perform a GC if they are the last thread
2473 // exiting the GCLocker.
2474 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2475   check_special_condition_for_native_trans(thread);
2476 
2477   // Finish the transition
2478   thread->set_thread_state(_thread_in_Java);
2479 
2480   if (thread->do_critical_native_unlock()) {
2481     ThreadInVMfromJavaNoAsyncException tiv(thread);
2482     GCLocker::unlock_critical(thread);
2483     thread->clear_critical_native_unlock();
2484   }
2485 }
2486 
2487 // We need to guarantee the Threads_lock here, since resumes are not
2488 // allowed during safepoint synchronization
2489 // Can only resume from an external suspension
2490 void JavaThread::java_resume() {
2491   assert_locked_or_safepoint(Threads_lock);
2492 
2493   // Sanity check: thread is gone, has started exiting or the thread
2494   // was not externally suspended.
2495   ThreadsListHandle tlh;
2496   if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2497     return;
2498   }
2499 
2500   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2501 
2502   clear_external_suspend();
2503 
2504   if (is_ext_suspended()) {
2505     clear_ext_suspended();
2506     SR_lock()->notify_all();
2507   }
2508 }
2509 
2510 size_t JavaThread::_stack_red_zone_size = 0;
2511 size_t JavaThread::_stack_yellow_zone_size = 0;
2512 size_t JavaThread::_stack_reserved_zone_size = 0;
2513 size_t JavaThread::_stack_shadow_zone_size = 0;
2514 
2515 void JavaThread::create_stack_guard_pages() {
2516   if (!os::uses_stack_guard_pages() ||
2517       _stack_guard_state != stack_guard_unused ||
2518       (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2519       log_info(os, thread)("Stack guard page creation for thread "
2520                            UINTX_FORMAT " disabled", os::current_thread_id());
2521     return;
2522   }
2523   address low_addr = stack_end();
2524   size_t len = stack_guard_zone_size();
2525 
2526   assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2527   assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2528 
2529   int must_commit = os::must_commit_stack_guard_pages();
2530   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2531 
2532   if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2533     log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2534     return;
2535   }
2536 
2537   if (os::guard_memory((char *) low_addr, len)) {
2538     _stack_guard_state = stack_guard_enabled;
2539   } else {
2540     log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2541       PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2542     if (os::uncommit_memory((char *) low_addr, len)) {
2543       log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2544     }
2545     return;
2546   }
2547 
2548   log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2549     PTR_FORMAT "-" PTR_FORMAT ".",
2550     os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2551 }
2552 
2553 void JavaThread::remove_stack_guard_pages() {
2554   assert(Thread::current() == this, "from different thread");
2555   if (_stack_guard_state == stack_guard_unused) return;
2556   address low_addr = stack_end();
2557   size_t len = stack_guard_zone_size();
2558 
2559   if (os::must_commit_stack_guard_pages()) {
2560     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2561       _stack_guard_state = stack_guard_unused;
2562     } else {
2563       log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2564         PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2565       return;
2566     }
2567   } else {
2568     if (_stack_guard_state == stack_guard_unused) return;
2569     if (os::unguard_memory((char *) low_addr, len)) {
2570       _stack_guard_state = stack_guard_unused;
2571     } else {
2572       log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2573         PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2574       return;
2575     }
2576   }
2577 
2578   log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2579     PTR_FORMAT "-" PTR_FORMAT ".",
2580     os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2581 }
2582 
2583 void JavaThread::enable_stack_reserved_zone() {
2584   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2585   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2586 
2587   // The base notation is from the stack's point of view, growing downward.
2588   // We need to adjust it to work correctly with guard_memory()
2589   address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2590 
2591   guarantee(base < stack_base(),"Error calculating stack reserved zone");
2592   guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2593 
2594   if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2595     _stack_guard_state = stack_guard_enabled;
2596   } else {
2597     warning("Attempt to guard stack reserved zone failed.");
2598   }
2599   enable_register_stack_guard();
2600 }
2601 
2602 void JavaThread::disable_stack_reserved_zone() {
2603   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2604   assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2605 
2606   // Simply return if called for a thread that does not use guard pages.
2607   if (_stack_guard_state == stack_guard_unused) return;
2608 
2609   // The base notation is from the stack's point of view, growing downward.
2610   // We need to adjust it to work correctly with guard_memory()
2611   address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2612 
2613   if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2614     _stack_guard_state = stack_guard_reserved_disabled;
2615   } else {
2616     warning("Attempt to unguard stack reserved zone failed.");
2617   }
2618   disable_register_stack_guard();
2619 }
2620 
2621 void JavaThread::enable_stack_yellow_reserved_zone() {
2622   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2623   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2624 
2625   // The base notation is from the stacks point of view, growing downward.
2626   // We need to adjust it to work correctly with guard_memory()
2627   address base = stack_red_zone_base();
2628 
2629   guarantee(base < stack_base(), "Error calculating stack yellow zone");
2630   guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2631 
2632   if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2633     _stack_guard_state = stack_guard_enabled;
2634   } else {
2635     warning("Attempt to guard stack yellow zone failed.");
2636   }
2637   enable_register_stack_guard();
2638 }
2639 
2640 void JavaThread::disable_stack_yellow_reserved_zone() {
2641   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2642   assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2643 
2644   // Simply return if called for a thread that does not use guard pages.
2645   if (_stack_guard_state == stack_guard_unused) return;
2646 
2647   // The base notation is from the stacks point of view, growing downward.
2648   // We need to adjust it to work correctly with guard_memory()
2649   address base = stack_red_zone_base();
2650 
2651   if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2652     _stack_guard_state = stack_guard_yellow_reserved_disabled;
2653   } else {
2654     warning("Attempt to unguard stack yellow zone failed.");
2655   }
2656   disable_register_stack_guard();
2657 }
2658 
2659 void JavaThread::enable_stack_red_zone() {
2660   // The base notation is from the stacks point of view, growing downward.
2661   // We need to adjust it to work correctly with guard_memory()
2662   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2663   address base = stack_red_zone_base() - stack_red_zone_size();
2664 
2665   guarantee(base < stack_base(), "Error calculating stack red zone");
2666   guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2667 
2668   if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2669     warning("Attempt to guard stack red zone failed.");
2670   }
2671 }
2672 
2673 void JavaThread::disable_stack_red_zone() {
2674   // The base notation is from the stacks point of view, growing downward.
2675   // We need to adjust it to work correctly with guard_memory()
2676   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2677   address base = stack_red_zone_base() - stack_red_zone_size();
2678   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2679     warning("Attempt to unguard stack red zone failed.");
2680   }
2681 }
2682 
2683 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2684   // ignore is there is no stack
2685   if (!has_last_Java_frame()) return;
2686   // traverse the stack frames. Starts from top frame.
2687   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2688     frame* fr = fst.current();
2689     f(fr, fst.register_map());
2690   }
2691 }
2692 
2693 
2694 #ifndef PRODUCT
2695 // Deoptimization
2696 // Function for testing deoptimization
2697 void JavaThread::deoptimize() {
2698   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2699   StackFrameStream fst(this, UseBiasedLocking);
2700   bool deopt = false;           // Dump stack only if a deopt actually happens.
2701   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2702   // Iterate over all frames in the thread and deoptimize
2703   for (; !fst.is_done(); fst.next()) {
2704     if (fst.current()->can_be_deoptimized()) {
2705 
2706       if (only_at) {
2707         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2708         // consists of comma or carriage return separated numbers so
2709         // search for the current bci in that string.
2710         address pc = fst.current()->pc();
2711         nmethod* nm =  (nmethod*) fst.current()->cb();
2712         ScopeDesc* sd = nm->scope_desc_at(pc);
2713         char buffer[8];
2714         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2715         size_t len = strlen(buffer);
2716         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2717         while (found != NULL) {
2718           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2719               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2720             // Check that the bci found is bracketed by terminators.
2721             break;
2722           }
2723           found = strstr(found + 1, buffer);
2724         }
2725         if (!found) {
2726           continue;
2727         }
2728       }
2729 
2730       if (DebugDeoptimization && !deopt) {
2731         deopt = true; // One-time only print before deopt
2732         tty->print_cr("[BEFORE Deoptimization]");
2733         trace_frames();
2734         trace_stack();
2735       }
2736       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2737     }
2738   }
2739 
2740   if (DebugDeoptimization && deopt) {
2741     tty->print_cr("[AFTER Deoptimization]");
2742     trace_frames();
2743   }
2744 }
2745 
2746 
2747 // Make zombies
2748 void JavaThread::make_zombies() {
2749   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2750     if (fst.current()->can_be_deoptimized()) {
2751       // it is a Java nmethod
2752       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2753       nm->make_not_entrant();
2754     }
2755   }
2756 }
2757 #endif // PRODUCT
2758 
2759 
2760 void JavaThread::deoptimized_wrt_marked_nmethods() {
2761   if (!has_last_Java_frame()) return;
2762   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2763   StackFrameStream fst(this, UseBiasedLocking);
2764   for (; !fst.is_done(); fst.next()) {
2765     if (fst.current()->should_be_deoptimized()) {
2766       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2767     }
2768   }
2769 }
2770 
2771 
2772 // If the caller is a NamedThread, then remember, in the current scope,
2773 // the given JavaThread in its _processed_thread field.
2774 class RememberProcessedThread: public StackObj {
2775   NamedThread* _cur_thr;
2776  public:
2777   RememberProcessedThread(JavaThread* jthr) {
2778     Thread* thread = Thread::current();
2779     if (thread->is_Named_thread()) {
2780       _cur_thr = (NamedThread *)thread;
2781       _cur_thr->set_processed_thread(jthr);
2782     } else {
2783       _cur_thr = NULL;
2784     }
2785   }
2786 
2787   ~RememberProcessedThread() {
2788     if (_cur_thr) {
2789       _cur_thr->set_processed_thread(NULL);
2790     }
2791   }
2792 };
2793 
2794 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2795   // Verify that the deferred card marks have been flushed.
2796   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2797 
2798   // Traverse the GCHandles
2799   Thread::oops_do(f, cf);
2800 
2801   JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2802 
2803   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2804          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2805 
2806   if (has_last_Java_frame()) {
2807     // Record JavaThread to GC thread
2808     RememberProcessedThread rpt(this);
2809 
2810     // Traverse the privileged stack
2811     if (_privileged_stack_top != NULL) {
2812       _privileged_stack_top->oops_do(f);
2813     }
2814 
2815     // traverse the registered growable array
2816     if (_array_for_gc != NULL) {
2817       for (int index = 0; index < _array_for_gc->length(); index++) {
2818         f->do_oop(_array_for_gc->adr_at(index));
2819       }
2820     }
2821 
2822     // Traverse the monitor chunks
2823     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2824       chunk->oops_do(f);
2825     }
2826 
2827     // Traverse the execution stack
2828     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2829       fst.current()->oops_do(f, cf, fst.register_map());
2830     }
2831   }
2832 
2833   // callee_target is never live across a gc point so NULL it here should
2834   // it still contain a methdOop.
2835 
2836   set_callee_target(NULL);
2837 
2838   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2839   // If we have deferred set_locals there might be oops waiting to be
2840   // written
2841   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2842   if (list != NULL) {
2843     for (int i = 0; i < list->length(); i++) {
2844       list->at(i)->oops_do(f);
2845     }
2846   }
2847 
2848   // Traverse instance variables at the end since the GC may be moving things
2849   // around using this function
2850   f->do_oop((oop*) &_threadObj);
2851   f->do_oop((oop*) &_vm_result);
2852   f->do_oop((oop*) &_exception_oop);
2853   f->do_oop((oop*) &_pending_async_exception);
2854 
2855   if (jvmti_thread_state() != NULL) {
2856     jvmti_thread_state()->oops_do(f);
2857   }
2858 }
2859 
2860 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2861   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2862          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2863 
2864   if (has_last_Java_frame()) {
2865     // Traverse the execution stack
2866     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2867       fst.current()->nmethods_do(cf);
2868     }
2869   }
2870 }
2871 
2872 void JavaThread::metadata_do(void f(Metadata*)) {
2873   if (has_last_Java_frame()) {
2874     // Traverse the execution stack to call f() on the methods in the stack
2875     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2876       fst.current()->metadata_do(f);
2877     }
2878   } else if (is_Compiler_thread()) {
2879     // need to walk ciMetadata in current compile tasks to keep alive.
2880     CompilerThread* ct = (CompilerThread*)this;
2881     if (ct->env() != NULL) {
2882       ct->env()->metadata_do(f);
2883     }
2884     CompileTask* task = ct->task();
2885     if (task != NULL) {
2886       task->metadata_do(f);
2887     }
2888   }
2889 }
2890 
2891 // Printing
2892 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2893   switch (_thread_state) {
2894   case _thread_uninitialized:     return "_thread_uninitialized";
2895   case _thread_new:               return "_thread_new";
2896   case _thread_new_trans:         return "_thread_new_trans";
2897   case _thread_in_native:         return "_thread_in_native";
2898   case _thread_in_native_trans:   return "_thread_in_native_trans";
2899   case _thread_in_vm:             return "_thread_in_vm";
2900   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2901   case _thread_in_Java:           return "_thread_in_Java";
2902   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2903   case _thread_blocked:           return "_thread_blocked";
2904   case _thread_blocked_trans:     return "_thread_blocked_trans";
2905   default:                        return "unknown thread state";
2906   }
2907 }
2908 
2909 #ifndef PRODUCT
2910 void JavaThread::print_thread_state_on(outputStream *st) const {
2911   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2912 };
2913 void JavaThread::print_thread_state() const {
2914   print_thread_state_on(tty);
2915 }
2916 #endif // PRODUCT
2917 
2918 // Called by Threads::print() for VM_PrintThreads operation
2919 void JavaThread::print_on(outputStream *st, bool extended_thread_info) const {
2920   st->print_raw("\"");
2921   st->print_raw(get_thread_name());
2922   st->print_raw("\" ");
2923   oop thread_oop = threadObj();
2924   if (thread_oop != NULL) {
2925     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2926     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2927     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2928   }
2929   Thread::print_on(st, extended_thread_info);
2930   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2931   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2932   if (thread_oop != NULL) {
2933     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2934   }
2935 #ifndef PRODUCT
2936   print_thread_state_on(st);
2937   _safepoint_state->print_on(st);
2938 #endif // PRODUCT
2939   if (is_Compiler_thread()) {
2940     CompileTask *task = ((CompilerThread*)this)->task();
2941     if (task != NULL) {
2942       st->print("   Compiling: ");
2943       task->print(st, NULL, true, false);
2944     } else {
2945       st->print("   No compile task");
2946     }
2947     st->cr();
2948   }
2949 }
2950 
2951 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2952   st->print("%s", get_thread_name_string(buf, buflen));
2953 }
2954 
2955 // Called by fatal error handler. The difference between this and
2956 // JavaThread::print() is that we can't grab lock or allocate memory.
2957 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2958   st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2959   oop thread_obj = threadObj();
2960   if (thread_obj != NULL) {
2961     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2962   }
2963   st->print(" [");
2964   st->print("%s", _get_thread_state_name(_thread_state));
2965   if (osthread()) {
2966     st->print(", id=%d", osthread()->thread_id());
2967   }
2968   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2969             p2i(stack_end()), p2i(stack_base()));
2970   st->print("]");
2971 
2972   ThreadsSMRSupport::print_info_on(this, st);
2973   return;
2974 }
2975 
2976 // Verification
2977 
2978 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2979 
2980 void JavaThread::verify() {
2981   // Verify oops in the thread.
2982   oops_do(&VerifyOopClosure::verify_oop, NULL);
2983 
2984   // Verify the stack frames.
2985   frames_do(frame_verify);
2986 }
2987 
2988 // CR 6300358 (sub-CR 2137150)
2989 // Most callers of this method assume that it can't return NULL but a
2990 // thread may not have a name whilst it is in the process of attaching to
2991 // the VM - see CR 6412693, and there are places where a JavaThread can be
2992 // seen prior to having it's threadObj set (eg JNI attaching threads and
2993 // if vm exit occurs during initialization). These cases can all be accounted
2994 // for such that this method never returns NULL.
2995 const char* JavaThread::get_thread_name() const {
2996 #ifdef ASSERT
2997   // early safepoints can hit while current thread does not yet have TLS
2998   if (!SafepointSynchronize::is_at_safepoint()) {
2999     Thread *cur = Thread::current();
3000     if (!(cur->is_Java_thread() && cur == this)) {
3001       // Current JavaThreads are allowed to get their own name without
3002       // the Threads_lock.
3003       assert_locked_or_safepoint(Threads_lock);
3004     }
3005   }
3006 #endif // ASSERT
3007   return get_thread_name_string();
3008 }
3009 
3010 // Returns a non-NULL representation of this thread's name, or a suitable
3011 // descriptive string if there is no set name
3012 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3013   const char* name_str;
3014   oop thread_obj = threadObj();
3015   if (thread_obj != NULL) {
3016     oop name = java_lang_Thread::name(thread_obj);
3017     if (name != NULL) {
3018       if (buf == NULL) {
3019         name_str = java_lang_String::as_utf8_string(name);
3020       } else {
3021         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3022       }
3023     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3024       name_str = "<no-name - thread is attaching>";
3025     } else {
3026       name_str = Thread::name();
3027     }
3028   } else {
3029     name_str = Thread::name();
3030   }
3031   assert(name_str != NULL, "unexpected NULL thread name");
3032   return name_str;
3033 }
3034 
3035 
3036 const char* JavaThread::get_threadgroup_name() const {
3037   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3038   oop thread_obj = threadObj();
3039   if (thread_obj != NULL) {
3040     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3041     if (thread_group != NULL) {
3042       // ThreadGroup.name can be null
3043       return java_lang_ThreadGroup::name(thread_group);
3044     }
3045   }
3046   return NULL;
3047 }
3048 
3049 const char* JavaThread::get_parent_name() const {
3050   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3051   oop thread_obj = threadObj();
3052   if (thread_obj != NULL) {
3053     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3054     if (thread_group != NULL) {
3055       oop parent = java_lang_ThreadGroup::parent(thread_group);
3056       if (parent != NULL) {
3057         // ThreadGroup.name can be null
3058         return java_lang_ThreadGroup::name(parent);
3059       }
3060     }
3061   }
3062   return NULL;
3063 }
3064 
3065 ThreadPriority JavaThread::java_priority() const {
3066   oop thr_oop = threadObj();
3067   if (thr_oop == NULL) return NormPriority; // Bootstrapping
3068   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3069   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3070   return priority;
3071 }
3072 
3073 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3074 
3075   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3076   // Link Java Thread object <-> C++ Thread
3077 
3078   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3079   // and put it into a new Handle.  The Handle "thread_oop" can then
3080   // be used to pass the C++ thread object to other methods.
3081 
3082   // Set the Java level thread object (jthread) field of the
3083   // new thread (a JavaThread *) to C++ thread object using the
3084   // "thread_oop" handle.
3085 
3086   // Set the thread field (a JavaThread *) of the
3087   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3088 
3089   Handle thread_oop(Thread::current(),
3090                     JNIHandles::resolve_non_null(jni_thread));
3091   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3092          "must be initialized");
3093   set_threadObj(thread_oop());
3094   java_lang_Thread::set_thread(thread_oop(), this);
3095 
3096   if (prio == NoPriority) {
3097     prio = java_lang_Thread::priority(thread_oop());
3098     assert(prio != NoPriority, "A valid priority should be present");
3099   }
3100 
3101   // Push the Java priority down to the native thread; needs Threads_lock
3102   Thread::set_priority(this, prio);
3103 
3104   // Add the new thread to the Threads list and set it in motion.
3105   // We must have threads lock in order to call Threads::add.
3106   // It is crucial that we do not block before the thread is
3107   // added to the Threads list for if a GC happens, then the java_thread oop
3108   // will not be visited by GC.
3109   Threads::add(this);
3110 }
3111 
3112 oop JavaThread::current_park_blocker() {
3113   // Support for JSR-166 locks
3114   oop thread_oop = threadObj();
3115   if (thread_oop != NULL &&
3116       JDK_Version::current().supports_thread_park_blocker()) {
3117     return java_lang_Thread::park_blocker(thread_oop);
3118   }
3119   return NULL;
3120 }
3121 
3122 
3123 void JavaThread::print_stack_on(outputStream* st) {
3124   if (!has_last_Java_frame()) return;
3125   ResourceMark rm;
3126   HandleMark   hm;
3127 
3128   RegisterMap reg_map(this);
3129   vframe* start_vf = last_java_vframe(&reg_map);
3130   int count = 0;
3131   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3132     if (f->is_java_frame()) {
3133       javaVFrame* jvf = javaVFrame::cast(f);
3134       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3135 
3136       // Print out lock information
3137       if (JavaMonitorsInStackTrace) {
3138         jvf->print_lock_info_on(st, count);
3139       }
3140     } else {
3141       // Ignore non-Java frames
3142     }
3143 
3144     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3145     count++;
3146     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3147   }
3148 }
3149 
3150 
3151 // JVMTI PopFrame support
3152 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3153   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3154   if (in_bytes(size_in_bytes) != 0) {
3155     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3156     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3157     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3158   }
3159 }
3160 
3161 void* JavaThread::popframe_preserved_args() {
3162   return _popframe_preserved_args;
3163 }
3164 
3165 ByteSize JavaThread::popframe_preserved_args_size() {
3166   return in_ByteSize(_popframe_preserved_args_size);
3167 }
3168 
3169 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3170   int sz = in_bytes(popframe_preserved_args_size());
3171   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3172   return in_WordSize(sz / wordSize);
3173 }
3174 
3175 void JavaThread::popframe_free_preserved_args() {
3176   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3177   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3178   _popframe_preserved_args = NULL;
3179   _popframe_preserved_args_size = 0;
3180 }
3181 
3182 #ifndef PRODUCT
3183 
3184 void JavaThread::trace_frames() {
3185   tty->print_cr("[Describe stack]");
3186   int frame_no = 1;
3187   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3188     tty->print("  %d. ", frame_no++);
3189     fst.current()->print_value_on(tty, this);
3190     tty->cr();
3191   }
3192 }
3193 
3194 class PrintAndVerifyOopClosure: public OopClosure {
3195  protected:
3196   template <class T> inline void do_oop_work(T* p) {
3197     oop obj = RawAccess<>::oop_load(p);
3198     if (obj == NULL) return;
3199     tty->print(INTPTR_FORMAT ": ", p2i(p));
3200     if (oopDesc::is_oop_or_null(obj)) {
3201       if (obj->is_objArray()) {
3202         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3203       } else {
3204         obj->print();
3205       }
3206     } else {
3207       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3208     }
3209     tty->cr();
3210   }
3211  public:
3212   virtual void do_oop(oop* p) { do_oop_work(p); }
3213   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3214 };
3215 
3216 
3217 static void oops_print(frame* f, const RegisterMap *map) {
3218   PrintAndVerifyOopClosure print;
3219   f->print_value();
3220   f->oops_do(&print, NULL, (RegisterMap*)map);
3221 }
3222 
3223 // Print our all the locations that contain oops and whether they are
3224 // valid or not.  This useful when trying to find the oldest frame
3225 // where an oop has gone bad since the frame walk is from youngest to
3226 // oldest.
3227 void JavaThread::trace_oops() {
3228   tty->print_cr("[Trace oops]");
3229   frames_do(oops_print);
3230 }
3231 
3232 
3233 #ifdef ASSERT
3234 // Print or validate the layout of stack frames
3235 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3236   ResourceMark rm;
3237   PRESERVE_EXCEPTION_MARK;
3238   FrameValues values;
3239   int frame_no = 0;
3240   for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3241     fst.current()->describe(values, ++frame_no);
3242     if (depth == frame_no) break;
3243   }
3244   if (validate_only) {
3245     values.validate();
3246   } else {
3247     tty->print_cr("[Describe stack layout]");
3248     values.print(this);
3249   }
3250 }
3251 #endif
3252 
3253 void JavaThread::trace_stack_from(vframe* start_vf) {
3254   ResourceMark rm;
3255   int vframe_no = 1;
3256   for (vframe* f = start_vf; f; f = f->sender()) {
3257     if (f->is_java_frame()) {
3258       javaVFrame::cast(f)->print_activation(vframe_no++);
3259     } else {
3260       f->print();
3261     }
3262     if (vframe_no > StackPrintLimit) {
3263       tty->print_cr("...<more frames>...");
3264       return;
3265     }
3266   }
3267 }
3268 
3269 
3270 void JavaThread::trace_stack() {
3271   if (!has_last_Java_frame()) return;
3272   ResourceMark rm;
3273   HandleMark   hm;
3274   RegisterMap reg_map(this);
3275   trace_stack_from(last_java_vframe(&reg_map));
3276 }
3277 
3278 
3279 #endif // PRODUCT
3280 
3281 
3282 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3283   assert(reg_map != NULL, "a map must be given");
3284   frame f = last_frame();
3285   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3286     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3287   }
3288   return NULL;
3289 }
3290 
3291 
3292 Klass* JavaThread::security_get_caller_class(int depth) {
3293   vframeStream vfst(this);
3294   vfst.security_get_caller_frame(depth);
3295   if (!vfst.at_end()) {
3296     return vfst.method()->method_holder();
3297   }
3298   return NULL;
3299 }
3300 
3301 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3302   assert(thread->is_Compiler_thread(), "must be compiler thread");
3303   CompileBroker::compiler_thread_loop();
3304 }
3305 
3306 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3307   NMethodSweeper::sweeper_loop();
3308 }
3309 
3310 // Create a CompilerThread
3311 CompilerThread::CompilerThread(CompileQueue* queue,
3312                                CompilerCounters* counters)
3313                                : JavaThread(&compiler_thread_entry) {
3314   _env   = NULL;
3315   _log   = NULL;
3316   _task  = NULL;
3317   _queue = queue;
3318   _counters = counters;
3319   _buffer_blob = NULL;
3320   _compiler = NULL;
3321 
3322   // Compiler uses resource area for compilation, let's bias it to mtCompiler
3323   resource_area()->bias_to(mtCompiler);
3324 
3325 #ifndef PRODUCT
3326   _ideal_graph_printer = NULL;
3327 #endif
3328 }
3329 
3330 CompilerThread::~CompilerThread() {
3331   // Delete objects which were allocated on heap.
3332   delete _counters;
3333 }
3334 
3335 bool CompilerThread::can_call_java() const {
3336   return _compiler != NULL && _compiler->is_jvmci();
3337 }
3338 
3339 // Create sweeper thread
3340 CodeCacheSweeperThread::CodeCacheSweeperThread()
3341 : JavaThread(&sweeper_thread_entry) {
3342   _scanned_compiled_method = NULL;
3343 }
3344 
3345 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3346   JavaThread::oops_do(f, cf);
3347   if (_scanned_compiled_method != NULL && cf != NULL) {
3348     // Safepoints can occur when the sweeper is scanning an nmethod so
3349     // process it here to make sure it isn't unloaded in the middle of
3350     // a scan.
3351     cf->do_code_blob(_scanned_compiled_method);
3352   }
3353 }
3354 
3355 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3356   JavaThread::nmethods_do(cf);
3357   if (_scanned_compiled_method != NULL && cf != NULL) {
3358     // Safepoints can occur when the sweeper is scanning an nmethod so
3359     // process it here to make sure it isn't unloaded in the middle of
3360     // a scan.
3361     cf->do_code_blob(_scanned_compiled_method);
3362   }
3363 }
3364 
3365 
3366 // ======= Threads ========
3367 
3368 // The Threads class links together all active threads, and provides
3369 // operations over all threads. It is protected by the Threads_lock,
3370 // which is also used in other global contexts like safepointing.
3371 // ThreadsListHandles are used to safely perform operations on one
3372 // or more threads without the risk of the thread exiting during the
3373 // operation.
3374 //
3375 // Note: The Threads_lock is currently more widely used than we
3376 // would like. We are actively migrating Threads_lock uses to other
3377 // mechanisms in order to reduce Threads_lock contention.
3378 
3379 JavaThread* Threads::_thread_list = NULL;
3380 int         Threads::_number_of_threads = 0;
3381 int         Threads::_number_of_non_daemon_threads = 0;
3382 int         Threads::_return_code = 0;
3383 int         Threads::_thread_claim_parity = 0;
3384 size_t      JavaThread::_stack_size_at_create = 0;
3385 
3386 #ifdef ASSERT
3387 bool        Threads::_vm_complete = false;
3388 #endif
3389 
3390 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3391   Prefetch::read((void*)addr, prefetch_interval);
3392   return *addr;
3393 }
3394 
3395 // Possibly the ugliest for loop the world has seen. C++ does not allow
3396 // multiple types in the declaration section of the for loop. In this case
3397 // we are only dealing with pointers and hence can cast them. It looks ugly
3398 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3399 #define DO_JAVA_THREADS(LIST, X)                                                                                          \
3400     for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes,                           \
3401              *MACRO_list = (JavaThread*)(LIST),                                                                           \
3402              **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(),  \
3403              **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(),                                     \
3404              *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval);                 \
3405          MACRO_current_p != MACRO_end;                                                                                    \
3406          MACRO_current_p++,                                                                                               \
3407              X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3408 
3409 // All JavaThreads
3410 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3411 
3412 // All non-JavaThreads (i.e., every non-JavaThread in the system).
3413 void Threads::non_java_threads_do(ThreadClosure* tc) {
3414   // Someday we could have a table or list of all non-JavaThreads.
3415   // For now, just manually iterate through them.
3416   tc->do_thread(VMThread::vm_thread());
3417   if (Universe::heap() != NULL) {
3418     Universe::heap()->gc_threads_do(tc);
3419   }
3420   WatcherThread *wt = WatcherThread::watcher_thread();
3421   // Strictly speaking, the following NULL check isn't sufficient to make sure
3422   // the data for WatcherThread is still valid upon being examined. However,
3423   // considering that WatchThread terminates when the VM is on the way to
3424   // exit at safepoint, the chance of the above is extremely small. The right
3425   // way to prevent termination of WatcherThread would be to acquire
3426   // Terminator_lock, but we can't do that without violating the lock rank
3427   // checking in some cases.
3428   if (wt != NULL) {
3429     tc->do_thread(wt);
3430   }
3431 
3432 #if INCLUDE_JFR
3433   Thread* sampler_thread = Jfr::sampler_thread();
3434   if (sampler_thread != NULL) {
3435     tc->do_thread(sampler_thread);
3436   }
3437 
3438 #endif
3439 
3440   // If CompilerThreads ever become non-JavaThreads, add them here
3441 }
3442 
3443 // All JavaThreads
3444 void Threads::java_threads_do(ThreadClosure* tc) {
3445   assert_locked_or_safepoint(Threads_lock);
3446   // ALL_JAVA_THREADS iterates through all JavaThreads.
3447   ALL_JAVA_THREADS(p) {
3448     tc->do_thread(p);
3449   }
3450 }
3451 
3452 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3453   assert_locked_or_safepoint(Threads_lock);
3454   java_threads_do(tc);
3455   tc->do_thread(VMThread::vm_thread());
3456 }
3457 
3458 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3459 void Threads::threads_do(ThreadClosure* tc) {
3460   assert_locked_or_safepoint(Threads_lock);
3461   java_threads_do(tc);
3462   non_java_threads_do(tc);
3463 }
3464 
3465 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3466   int cp = Threads::thread_claim_parity();
3467   ALL_JAVA_THREADS(p) {
3468     if (p->claim_oops_do(is_par, cp)) {
3469       tc->do_thread(p);
3470     }
3471   }
3472   VMThread* vmt = VMThread::vm_thread();
3473   if (vmt->claim_oops_do(is_par, cp)) {
3474     tc->do_thread(vmt);
3475   }
3476 }
3477 
3478 // The system initialization in the library has three phases.
3479 //
3480 // Phase 1: java.lang.System class initialization
3481 //     java.lang.System is a primordial class loaded and initialized
3482 //     by the VM early during startup.  java.lang.System.<clinit>
3483 //     only does registerNatives and keeps the rest of the class
3484 //     initialization work later until thread initialization completes.
3485 //
3486 //     System.initPhase1 initializes the system properties, the static
3487 //     fields in, out, and err. Set up java signal handlers, OS-specific
3488 //     system settings, and thread group of the main thread.
3489 static void call_initPhase1(TRAPS) {
3490   Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3491   JavaValue result(T_VOID);
3492   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3493                                          vmSymbols::void_method_signature(), CHECK);
3494 }
3495 
3496 // Phase 2. Module system initialization
3497 //     This will initialize the module system.  Only java.base classes
3498 //     can be loaded until phase 2 completes.
3499 //
3500 //     Call System.initPhase2 after the compiler initialization and jsr292
3501 //     classes get initialized because module initialization runs a lot of java
3502 //     code, that for performance reasons, should be compiled.  Also, this will
3503 //     enable the startup code to use lambda and other language features in this
3504 //     phase and onward.
3505 //
3506 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3507 static void call_initPhase2(TRAPS) {
3508   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3509 
3510   Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3511 
3512   JavaValue result(T_INT);
3513   JavaCallArguments args;
3514   args.push_int(DisplayVMOutputToStderr);
3515   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3516   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3517                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3518   if (result.get_jint() != JNI_OK) {
3519     vm_exit_during_initialization(); // no message or exception
3520   }
3521 
3522   universe_post_module_init();
3523 }
3524 
3525 // Phase 3. final setup - set security manager, system class loader and TCCL
3526 //
3527 //     This will instantiate and set the security manager, set the system class
3528 //     loader as well as the thread context class loader.  The security manager
3529 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
3530 //     other modules or the application's classpath.
3531 static void call_initPhase3(TRAPS) {
3532   Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3533   JavaValue result(T_VOID);
3534   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3535                                          vmSymbols::void_method_signature(), CHECK);
3536 }
3537 
3538 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3539   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3540 
3541   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3542     create_vm_init_libraries();
3543   }
3544 
3545   initialize_class(vmSymbols::java_lang_String(), CHECK);
3546 
3547   // Inject CompactStrings value after the static initializers for String ran.
3548   java_lang_String::set_compact_strings(CompactStrings);
3549 
3550   // Initialize java_lang.System (needed before creating the thread)
3551   initialize_class(vmSymbols::java_lang_System(), CHECK);
3552   // The VM creates & returns objects of this class. Make sure it's initialized.
3553   initialize_class(vmSymbols::java_lang_Class(), CHECK);
3554   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3555   Handle thread_group = create_initial_thread_group(CHECK);
3556   Universe::set_main_thread_group(thread_group());
3557   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3558   oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3559   main_thread->set_threadObj(thread_object);
3560   // Set thread status to running since main thread has
3561   // been started and running.
3562   java_lang_Thread::set_thread_status(thread_object,
3563                                       java_lang_Thread::RUNNABLE);
3564 
3565   // The VM creates objects of this class.
3566   initialize_class(vmSymbols::java_lang_Module(), CHECK);
3567 
3568   // The VM preresolves methods to these classes. Make sure that they get initialized
3569   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3570   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3571 
3572   // Phase 1 of the system initialization in the library, java.lang.System class initialization
3573   call_initPhase1(CHECK);
3574 
3575   // get the Java runtime name after java.lang.System is initialized
3576   JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3577   JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3578 
3579   // an instance of OutOfMemory exception has been allocated earlier
3580   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3581   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3582   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3583   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3584   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3585   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3586   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3587   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3588 }
3589 
3590 void Threads::initialize_jsr292_core_classes(TRAPS) {
3591   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3592 
3593   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3594   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3595   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3596   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3597 }
3598 
3599 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3600   extern void JDK_Version_init();
3601 
3602   // Preinitialize version info.
3603   VM_Version::early_initialize();
3604 
3605   // Check version
3606   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3607 
3608   // Initialize library-based TLS
3609   ThreadLocalStorage::init();
3610 
3611   // Initialize the output stream module
3612   ostream_init();
3613 
3614   // Process java launcher properties.
3615   Arguments::process_sun_java_launcher_properties(args);
3616 
3617   // Initialize the os module
3618   os::init();
3619 
3620   // Record VM creation timing statistics
3621   TraceVmCreationTime create_vm_timer;
3622   create_vm_timer.start();
3623 
3624   // Initialize system properties.
3625   Arguments::init_system_properties();
3626 
3627   // So that JDK version can be used as a discriminator when parsing arguments
3628   JDK_Version_init();
3629 
3630   // Update/Initialize System properties after JDK version number is known
3631   Arguments::init_version_specific_system_properties();
3632 
3633   // Make sure to initialize log configuration *before* parsing arguments
3634   LogConfiguration::initialize(create_vm_timer.begin_time());
3635 
3636   // Parse arguments
3637   // Note: this internally calls os::init_container_support()
3638   jint parse_result = Arguments::parse(args);
3639   if (parse_result != JNI_OK) return parse_result;
3640 
3641   os::init_before_ergo();
3642 
3643   jint ergo_result = Arguments::apply_ergo();
3644   if (ergo_result != JNI_OK) return ergo_result;
3645 
3646   // Final check of all ranges after ergonomics which may change values.
3647   if (!JVMFlagRangeList::check_ranges()) {
3648     return JNI_EINVAL;
3649   }
3650 
3651   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3652   bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3653   if (!constraint_result) {
3654     return JNI_EINVAL;
3655   }
3656 
3657   JVMFlagWriteableList::mark_startup();
3658 
3659   if (PauseAtStartup) {
3660     os::pause();
3661   }
3662 
3663   HOTSPOT_VM_INIT_BEGIN();
3664 
3665   // Timing (must come after argument parsing)
3666   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3667 
3668 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3669   // Initialize assert poison page mechanism.
3670   if (ShowRegistersOnAssert) {
3671     initialize_assert_poison();
3672   }
3673 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3674 
3675   // Initialize the os module after parsing the args
3676   jint os_init_2_result = os::init_2();
3677   if (os_init_2_result != JNI_OK) return os_init_2_result;
3678 
3679   SafepointMechanism::initialize();
3680 
3681   jint adjust_after_os_result = Arguments::adjust_after_os();
3682   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3683 
3684   // Initialize output stream logging
3685   ostream_init_log();
3686 
3687   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3688   // Must be before create_vm_init_agents()
3689   if (Arguments::init_libraries_at_startup()) {
3690     convert_vm_init_libraries_to_agents();
3691   }
3692 
3693   // Launch -agentlib/-agentpath and converted -Xrun agents
3694   if (Arguments::init_agents_at_startup()) {
3695     create_vm_init_agents();
3696   }
3697 
3698   // Initialize Threads state
3699   _thread_list = NULL;
3700   _number_of_threads = 0;
3701   _number_of_non_daemon_threads = 0;
3702 
3703   // Initialize global data structures and create system classes in heap
3704   vm_init_globals();
3705 
3706 #if INCLUDE_JVMCI
3707   if (JVMCICounterSize > 0) {
3708     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3709     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3710   } else {
3711     JavaThread::_jvmci_old_thread_counters = NULL;
3712   }
3713 #endif // INCLUDE_JVMCI
3714 
3715   // Attach the main thread to this os thread
3716   JavaThread* main_thread = new JavaThread();
3717   main_thread->set_thread_state(_thread_in_vm);
3718   main_thread->initialize_thread_current();
3719   // must do this before set_active_handles
3720   main_thread->record_stack_base_and_size();
3721   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3722 
3723   if (!main_thread->set_as_starting_thread()) {
3724     vm_shutdown_during_initialization(
3725                                       "Failed necessary internal allocation. Out of swap space");
3726     main_thread->smr_delete();
3727     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3728     return JNI_ENOMEM;
3729   }
3730 
3731   // Enable guard page *after* os::create_main_thread(), otherwise it would
3732   // crash Linux VM, see notes in os_linux.cpp.
3733   main_thread->create_stack_guard_pages();
3734 
3735   // Initialize Java-Level synchronization subsystem
3736   ObjectMonitor::Initialize();
3737 
3738   // Initialize global modules
3739   jint status = init_globals();
3740   if (status != JNI_OK) {
3741     main_thread->smr_delete();
3742     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3743     return status;
3744   }
3745 
3746   JFR_ONLY(Jfr::on_vm_init();)
3747 
3748   // Should be done after the heap is fully created
3749   main_thread->cache_global_variables();
3750 
3751   HandleMark hm;
3752 
3753   { MutexLocker mu(Threads_lock);
3754     Threads::add(main_thread);
3755   }
3756 
3757   // Any JVMTI raw monitors entered in onload will transition into
3758   // real raw monitor. VM is setup enough here for raw monitor enter.
3759   JvmtiExport::transition_pending_onload_raw_monitors();
3760 
3761   // Create the VMThread
3762   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3763 
3764   VMThread::create();
3765     Thread* vmthread = VMThread::vm_thread();
3766 
3767     if (!os::create_thread(vmthread, os::vm_thread)) {
3768       vm_exit_during_initialization("Cannot create VM thread. "
3769                                     "Out of system resources.");
3770     }
3771 
3772     // Wait for the VM thread to become ready, and VMThread::run to initialize
3773     // Monitors can have spurious returns, must always check another state flag
3774     {
3775       MutexLocker ml(Notify_lock);
3776       os::start_thread(vmthread);
3777       while (vmthread->active_handles() == NULL) {
3778         Notify_lock->wait();
3779       }
3780     }
3781   }
3782 
3783   assert(Universe::is_fully_initialized(), "not initialized");
3784   if (VerifyDuringStartup) {
3785     // Make sure we're starting with a clean slate.
3786     VM_Verify verify_op;
3787     VMThread::execute(&verify_op);
3788   }
3789 
3790   Thread* THREAD = Thread::current();
3791 
3792   // Always call even when there are not JVMTI environments yet, since environments
3793   // may be attached late and JVMTI must track phases of VM execution
3794   JvmtiExport::enter_early_start_phase();
3795 
3796   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3797   JvmtiExport::post_early_vm_start();
3798 
3799   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3800 
3801   // We need this to update the java.vm.info property in case any flags used
3802   // to initially define it have been changed. This is needed for both CDS and
3803   // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3804   // is initially computed. See Abstract_VM_Version::vm_info_string().
3805   reset_vm_info_property(CHECK_JNI_ERR);
3806 
3807   quicken_jni_functions();
3808 
3809   // No more stub generation allowed after that point.
3810   StubCodeDesc::freeze();
3811 
3812   // Set flag that basic initialization has completed. Used by exceptions and various
3813   // debug stuff, that does not work until all basic classes have been initialized.
3814   set_init_completed();
3815 
3816   LogConfiguration::post_initialize();
3817   Metaspace::post_initialize();
3818 
3819   HOTSPOT_VM_INIT_END();
3820 
3821   // record VM initialization completion time
3822 #if INCLUDE_MANAGEMENT
3823   Management::record_vm_init_completed();
3824 #endif // INCLUDE_MANAGEMENT
3825 
3826   // Signal Dispatcher needs to be started before VMInit event is posted
3827   os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3828 
3829   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3830   if (!DisableAttachMechanism) {
3831     AttachListener::vm_start();
3832     if (StartAttachListener || AttachListener::init_at_startup()) {
3833       AttachListener::init();
3834     }
3835   }
3836 
3837   // Launch -Xrun agents
3838   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3839   // back-end can launch with -Xdebug -Xrunjdwp.
3840   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3841     create_vm_init_libraries();
3842   }
3843 
3844   if (CleanChunkPoolAsync) {
3845     Chunk::start_chunk_pool_cleaner_task();
3846   }
3847 
3848   // initialize compiler(s)
3849 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3850 #if INCLUDE_JVMCI
3851   bool force_JVMCI_intialization = false;
3852   if (EnableJVMCI) {
3853     // Initialize JVMCI eagerly when it is explicitly requested.
3854     // Or when JVMCIPrintProperties is enabled.
3855     // The JVMCI Java initialization code will read this flag and
3856     // do the printing if it's set.
3857     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3858 
3859     if (!force_JVMCI_intialization) {
3860       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3861       // compilations via JVMCI will not actually block until JVMCI is initialized.
3862       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3863     }
3864   }
3865 #endif
3866   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3867   // Postpone completion of compiler initialization to after JVMCI
3868   // is initialized to avoid timeouts of blocking compilations.
3869   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3870     CompileBroker::compilation_init_phase2();
3871   }
3872 #endif
3873 
3874   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3875   // It is done after compilers are initialized, because otherwise compilations of
3876   // signature polymorphic MH intrinsics can be missed
3877   // (see SystemDictionary::find_method_handle_intrinsic).
3878   initialize_jsr292_core_classes(CHECK_JNI_ERR);
3879 
3880   // This will initialize the module system.  Only java.base classes can be
3881   // loaded until phase 2 completes
3882   call_initPhase2(CHECK_JNI_ERR);
3883 
3884   // Always call even when there are not JVMTI environments yet, since environments
3885   // may be attached late and JVMTI must track phases of VM execution
3886   JvmtiExport::enter_start_phase();
3887 
3888   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3889   JvmtiExport::post_vm_start();
3890 
3891   // Final system initialization including security manager and system class loader
3892   call_initPhase3(CHECK_JNI_ERR);
3893 
3894   // cache the system and platform class loaders
3895   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3896 
3897 #if INCLUDE_CDS
3898   if (DumpSharedSpaces) {
3899     // capture the module path info from the ModuleEntryTable
3900     ClassLoader::initialize_module_path(THREAD);
3901   }
3902 #endif
3903 
3904 #if INCLUDE_JVMCI
3905   if (force_JVMCI_intialization) {
3906     JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3907     CompileBroker::compilation_init_phase2();
3908   }
3909 #endif
3910 
3911   // Always call even when there are not JVMTI environments yet, since environments
3912   // may be attached late and JVMTI must track phases of VM execution
3913   JvmtiExport::enter_live_phase();
3914 
3915   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3916   JvmtiExport::post_vm_initialized();
3917 
3918   JFR_ONLY(Jfr::on_vm_start();)
3919 
3920 #if INCLUDE_MANAGEMENT
3921   Management::initialize(THREAD);
3922 
3923   if (HAS_PENDING_EXCEPTION) {
3924     // management agent fails to start possibly due to
3925     // configuration problem and is responsible for printing
3926     // stack trace if appropriate. Simply exit VM.
3927     vm_exit(1);
3928   }
3929 #endif // INCLUDE_MANAGEMENT
3930 
3931   if (MemProfiling)                   MemProfiler::engage();
3932   StatSampler::engage();
3933   if (CheckJNICalls)                  JniPeriodicChecker::engage();
3934 
3935   BiasedLocking::init();
3936 
3937 #if INCLUDE_RTM_OPT
3938   RTMLockingCounters::init();
3939 #endif
3940 
3941   if (JDK_Version::current().post_vm_init_hook_enabled()) {
3942     call_postVMInitHook(THREAD);
3943     // The Java side of PostVMInitHook.run must deal with all
3944     // exceptions and provide means of diagnosis.
3945     if (HAS_PENDING_EXCEPTION) {
3946       CLEAR_PENDING_EXCEPTION;
3947     }
3948   }
3949 
3950   {
3951     MutexLocker ml(PeriodicTask_lock);
3952     // Make sure the WatcherThread can be started by WatcherThread::start()
3953     // or by dynamic enrollment.
3954     WatcherThread::make_startable();
3955     // Start up the WatcherThread if there are any periodic tasks
3956     // NOTE:  All PeriodicTasks should be registered by now. If they
3957     //   aren't, late joiners might appear to start slowly (we might
3958     //   take a while to process their first tick).
3959     if (PeriodicTask::num_tasks() > 0) {
3960       WatcherThread::start();
3961     }
3962   }
3963 
3964   create_vm_timer.end();
3965 #ifdef ASSERT
3966   _vm_complete = true;
3967 #endif
3968 
3969   if (DumpSharedSpaces) {
3970     MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3971     ShouldNotReachHere();
3972   }
3973 
3974   return JNI_OK;
3975 }
3976 
3977 // type for the Agent_OnLoad and JVM_OnLoad entry points
3978 extern "C" {
3979   typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3980 }
3981 // Find a command line agent library and return its entry point for
3982 //         -agentlib:  -agentpath:   -Xrun
3983 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3984 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3985                                     const char *on_load_symbols[],
3986                                     size_t num_symbol_entries) {
3987   OnLoadEntry_t on_load_entry = NULL;
3988   void *library = NULL;
3989 
3990   if (!agent->valid()) {
3991     char buffer[JVM_MAXPATHLEN];
3992     char ebuf[1024] = "";
3993     const char *name = agent->name();
3994     const char *msg = "Could not find agent library ";
3995 
3996     // First check to see if agent is statically linked into executable
3997     if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3998       library = agent->os_lib();
3999     } else if (agent->is_absolute_path()) {
4000       library = os::dll_load(name, ebuf, sizeof ebuf);
4001       if (library == NULL) {
4002         const char *sub_msg = " in absolute path, with error: ";
4003         size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4004         char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4005         jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4006         // If we can't find the agent, exit.
4007         vm_exit_during_initialization(buf, NULL);
4008         FREE_C_HEAP_ARRAY(char, buf);
4009       }
4010     } else {
4011       // Try to load the agent from the standard dll directory
4012       if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4013                              name)) {
4014         library = os::dll_load(buffer, ebuf, sizeof ebuf);
4015       }
4016       if (library == NULL) { // Try the library path directory.
4017         if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4018           library = os::dll_load(buffer, ebuf, sizeof ebuf);
4019         }
4020         if (library == NULL) {
4021           const char *sub_msg = " on the library path, with error: ";
4022           const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4023 
4024           size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4025                        strlen(ebuf) + strlen(sub_msg2) + 1;
4026           char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4027           if (!agent->is_instrument_lib()) {
4028             jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4029           } else {
4030             jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4031           }
4032           // If we can't find the agent, exit.
4033           vm_exit_during_initialization(buf, NULL);
4034           FREE_C_HEAP_ARRAY(char, buf);
4035         }
4036       }
4037     }
4038     agent->set_os_lib(library);
4039     agent->set_valid();
4040   }
4041 
4042   // Find the OnLoad function.
4043   on_load_entry =
4044     CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4045                                                           false,
4046                                                           on_load_symbols,
4047                                                           num_symbol_entries));
4048   return on_load_entry;
4049 }
4050 
4051 // Find the JVM_OnLoad entry point
4052 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4053   const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4054   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4055 }
4056 
4057 // Find the Agent_OnLoad entry point
4058 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4059   const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4060   return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4061 }
4062 
4063 // For backwards compatibility with -Xrun
4064 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4065 // treated like -agentpath:
4066 // Must be called before agent libraries are created
4067 void Threads::convert_vm_init_libraries_to_agents() {
4068   AgentLibrary* agent;
4069   AgentLibrary* next;
4070 
4071   for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4072     next = agent->next();  // cache the next agent now as this agent may get moved off this list
4073     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4074 
4075     // If there is an JVM_OnLoad function it will get called later,
4076     // otherwise see if there is an Agent_OnLoad
4077     if (on_load_entry == NULL) {
4078       on_load_entry = lookup_agent_on_load(agent);
4079       if (on_load_entry != NULL) {
4080         // switch it to the agent list -- so that Agent_OnLoad will be called,
4081         // JVM_OnLoad won't be attempted and Agent_OnUnload will
4082         Arguments::convert_library_to_agent(agent);
4083       } else {
4084         vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4085       }
4086     }
4087   }
4088 }
4089 
4090 // Create agents for -agentlib:  -agentpath:  and converted -Xrun
4091 // Invokes Agent_OnLoad
4092 // Called very early -- before JavaThreads exist
4093 void Threads::create_vm_init_agents() {
4094   extern struct JavaVM_ main_vm;
4095   AgentLibrary* agent;
4096 
4097   JvmtiExport::enter_onload_phase();
4098 
4099   for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4100     OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
4101 
4102     if (on_load_entry != NULL) {
4103       // Invoke the Agent_OnLoad function
4104       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4105       if (err != JNI_OK) {
4106         vm_exit_during_initialization("agent library failed to init", agent->name());
4107       }
4108     } else {
4109       vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4110     }
4111   }
4112   JvmtiExport::enter_primordial_phase();
4113 }
4114 
4115 extern "C" {
4116   typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4117 }
4118 
4119 void Threads::shutdown_vm_agents() {
4120   // Send any Agent_OnUnload notifications
4121   const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4122   size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4123   extern struct JavaVM_ main_vm;
4124   for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4125 
4126     // Find the Agent_OnUnload function.
4127     Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4128                                                    os::find_agent_function(agent,
4129                                                    false,
4130                                                    on_unload_symbols,
4131                                                    num_symbol_entries));
4132 
4133     // Invoke the Agent_OnUnload function
4134     if (unload_entry != NULL) {
4135       JavaThread* thread = JavaThread::current();
4136       ThreadToNativeFromVM ttn(thread);
4137       HandleMark hm(thread);
4138       (*unload_entry)(&main_vm);
4139     }
4140   }
4141 }
4142 
4143 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4144 // Invokes JVM_OnLoad
4145 void Threads::create_vm_init_libraries() {
4146   extern struct JavaVM_ main_vm;
4147   AgentLibrary* agent;
4148 
4149   for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4150     OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4151 
4152     if (on_load_entry != NULL) {
4153       // Invoke the JVM_OnLoad function
4154       JavaThread* thread = JavaThread::current();
4155       ThreadToNativeFromVM ttn(thread);
4156       HandleMark hm(thread);
4157       jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4158       if (err != JNI_OK) {
4159         vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4160       }
4161     } else {
4162       vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4163     }
4164   }
4165 }
4166 
4167 
4168 // Last thread running calls java.lang.Shutdown.shutdown()
4169 void JavaThread::invoke_shutdown_hooks() {
4170   HandleMark hm(this);
4171 
4172   // We could get here with a pending exception, if so clear it now.
4173   if (this->has_pending_exception()) {
4174     this->clear_pending_exception();
4175   }
4176 
4177   EXCEPTION_MARK;
4178   Klass* shutdown_klass =
4179     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4180                                       THREAD);
4181   if (shutdown_klass != NULL) {
4182     // SystemDictionary::resolve_or_null will return null if there was
4183     // an exception.  If we cannot load the Shutdown class, just don't
4184     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
4185     // won't be run.  Note that if a shutdown hook was registered,
4186     // the Shutdown class would have already been loaded
4187     // (Runtime.addShutdownHook will load it).
4188     JavaValue result(T_VOID);
4189     JavaCalls::call_static(&result,
4190                            shutdown_klass,
4191                            vmSymbols::shutdown_method_name(),
4192                            vmSymbols::void_method_signature(),
4193                            THREAD);
4194   }
4195   CLEAR_PENDING_EXCEPTION;
4196 }
4197 
4198 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4199 // the program falls off the end of main(). Another VM exit path is through
4200 // vm_exit() when the program calls System.exit() to return a value or when
4201 // there is a serious error in VM. The two shutdown paths are not exactly
4202 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4203 // and VM_Exit op at VM level.
4204 //
4205 // Shutdown sequence:
4206 //   + Shutdown native memory tracking if it is on
4207 //   + Wait until we are the last non-daemon thread to execute
4208 //     <-- every thing is still working at this moment -->
4209 //   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4210 //        shutdown hooks
4211 //   + Call before_exit(), prepare for VM exit
4212 //      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4213 //        currently the only user of this mechanism is File.deleteOnExit())
4214 //      > stop StatSampler, watcher thread, CMS threads,
4215 //        post thread end and vm death events to JVMTI,
4216 //        stop signal thread
4217 //   + Call JavaThread::exit(), it will:
4218 //      > release JNI handle blocks, remove stack guard pages
4219 //      > remove this thread from Threads list
4220 //     <-- no more Java code from this thread after this point -->
4221 //   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4222 //     the compiler threads at safepoint
4223 //     <-- do not use anything that could get blocked by Safepoint -->
4224 //   + Disable tracing at JNI/JVM barriers
4225 //   + Set _vm_exited flag for threads that are still running native code
4226 //   + Delete this thread
4227 //   + Call exit_globals()
4228 //      > deletes tty
4229 //      > deletes PerfMemory resources
4230 //   + Return to caller
4231 
4232 bool Threads::destroy_vm() {
4233   JavaThread* thread = JavaThread::current();
4234 
4235 #ifdef ASSERT
4236   _vm_complete = false;
4237 #endif
4238   // Wait until we are the last non-daemon thread to execute
4239   { MutexLocker nu(Threads_lock);
4240     while (Threads::number_of_non_daemon_threads() > 1)
4241       // This wait should make safepoint checks, wait without a timeout,
4242       // and wait as a suspend-equivalent condition.
4243       Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4244                          Mutex::_as_suspend_equivalent_flag);
4245   }
4246 
4247   EventShutdown e;
4248   if (e.should_commit()) {
4249     e.set_reason("No remaining non-daemon Java threads");
4250     e.commit();
4251   }
4252 
4253   // Hang forever on exit if we are reporting an error.
4254   if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4255     os::infinite_sleep();
4256   }
4257   os::wait_for_keypress_at_exit();
4258 
4259   // run Java level shutdown hooks
4260   thread->invoke_shutdown_hooks();
4261 
4262   before_exit(thread);
4263 
4264   thread->exit(true);
4265 
4266   // Stop VM thread.
4267   {
4268     // 4945125 The vm thread comes to a safepoint during exit.
4269     // GC vm_operations can get caught at the safepoint, and the
4270     // heap is unparseable if they are caught. Grab the Heap_lock
4271     // to prevent this. The GC vm_operations will not be able to
4272     // queue until after the vm thread is dead. After this point,
4273     // we'll never emerge out of the safepoint before the VM exits.
4274 
4275     MutexLocker ml(Heap_lock);
4276 
4277     VMThread::wait_for_vm_thread_exit();
4278     assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4279     VMThread::destroy();
4280   }
4281 
4282   // Now, all Java threads are gone except daemon threads. Daemon threads
4283   // running Java code or in VM are stopped by the Safepoint. However,
4284   // daemon threads executing native code are still running.  But they
4285   // will be stopped at native=>Java/VM barriers. Note that we can't
4286   // simply kill or suspend them, as it is inherently deadlock-prone.
4287 
4288   VM_Exit::set_vm_exited();
4289 
4290   // Clean up ideal graph printers after the VMThread has started
4291   // the final safepoint which will block all the Compiler threads.
4292   // Note that this Thread has already logically exited so the
4293   // clean_up() function's use of a JavaThreadIteratorWithHandle
4294   // would be a problem except set_vm_exited() has remembered the
4295   // shutdown thread which is granted a policy exception.
4296 #if defined(COMPILER2) && !defined(PRODUCT)
4297   IdealGraphPrinter::clean_up();
4298 #endif
4299 
4300   notify_vm_shutdown();
4301 
4302   // We are after VM_Exit::set_vm_exited() so we can't call
4303   // thread->smr_delete() or we will block on the Threads_lock.
4304   // Deleting the shutdown thread here is safe because another
4305   // JavaThread cannot have an active ThreadsListHandle for
4306   // this JavaThread.
4307   delete thread;
4308 
4309 #if INCLUDE_JVMCI
4310   if (JVMCICounterSize > 0) {
4311     FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4312   }
4313 #endif
4314 
4315   // exit_globals() will delete tty
4316   exit_globals();
4317 
4318   LogConfiguration::finalize();
4319 
4320   return true;
4321 }
4322 
4323 
4324 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4325   if (version == JNI_VERSION_1_1) return JNI_TRUE;
4326   return is_supported_jni_version(version);
4327 }
4328 
4329 
4330 jboolean Threads::is_supported_jni_version(jint version) {
4331   if (version == JNI_VERSION_1_2) return JNI_TRUE;
4332   if (version == JNI_VERSION_1_4) return JNI_TRUE;
4333   if (version == JNI_VERSION_1_6) return JNI_TRUE;
4334   if (version == JNI_VERSION_1_8) return JNI_TRUE;
4335   if (version == JNI_VERSION_9) return JNI_TRUE;
4336   if (version == JNI_VERSION_10) return JNI_TRUE;
4337   return JNI_FALSE;
4338 }
4339 
4340 
4341 void Threads::add(JavaThread* p, bool force_daemon) {
4342   // The threads lock must be owned at this point
4343   assert_locked_or_safepoint(Threads_lock);
4344 
4345   BarrierSet::barrier_set()->on_thread_attach(p);
4346 
4347   p->set_next(_thread_list);
4348   _thread_list = p;
4349 
4350   // Once a JavaThread is added to the Threads list, smr_delete() has
4351   // to be used to delete it. Otherwise we can just delete it directly.
4352   p->set_on_thread_list();
4353 
4354   _number_of_threads++;
4355   oop threadObj = p->threadObj();
4356   bool daemon = true;
4357   // Bootstrapping problem: threadObj can be null for initial
4358   // JavaThread (or for threads attached via JNI)
4359   if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4360     _number_of_non_daemon_threads++;
4361     daemon = false;
4362   }
4363 
4364   ThreadService::add_thread(p, daemon);
4365 
4366   // Maintain fast thread list
4367   ThreadsSMRSupport::add_thread(p);
4368 
4369   // Possible GC point.
4370   Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4371 }
4372 
4373 void Threads::remove(JavaThread* p) {
4374 
4375   // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4376   ObjectSynchronizer::omFlush(p);
4377 
4378   // Extra scope needed for Thread_lock, so we can check
4379   // that we do not remove thread without safepoint code notice
4380   { MutexLocker ml(Threads_lock);
4381 
4382     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4383 
4384     // Maintain fast thread list
4385     ThreadsSMRSupport::remove_thread(p);
4386 
4387     JavaThread* current = _thread_list;
4388     JavaThread* prev    = NULL;
4389 
4390     while (current != p) {
4391       prev    = current;
4392       current = current->next();
4393     }
4394 
4395     if (prev) {
4396       prev->set_next(current->next());
4397     } else {
4398       _thread_list = p->next();
4399     }
4400 
4401     _number_of_threads--;
4402     oop threadObj = p->threadObj();
4403     bool daemon = true;
4404     if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4405       _number_of_non_daemon_threads--;
4406       daemon = false;
4407 
4408       // Only one thread left, do a notify on the Threads_lock so a thread waiting
4409       // on destroy_vm will wake up.
4410       if (number_of_non_daemon_threads() == 1) {
4411         Threads_lock->notify_all();
4412       }
4413     }
4414     ThreadService::remove_thread(p, daemon);
4415 
4416     // Make sure that safepoint code disregard this thread. This is needed since
4417     // the thread might mess around with locks after this point. This can cause it
4418     // to do callbacks into the safepoint code. However, the safepoint code is not aware
4419     // of this thread since it is removed from the queue.
4420     p->set_terminated_value();
4421   } // unlock Threads_lock
4422 
4423   // Since Events::log uses a lock, we grab it outside the Threads_lock
4424   Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4425 }
4426 
4427 // Operations on the Threads list for GC.  These are not explicitly locked,
4428 // but the garbage collector must provide a safe context for them to run.
4429 // In particular, these things should never be called when the Threads_lock
4430 // is held by some other thread. (Note: the Safepoint abstraction also
4431 // uses the Threads_lock to guarantee this property. It also makes sure that
4432 // all threads gets blocked when exiting or starting).
4433 
4434 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4435   ALL_JAVA_THREADS(p) {
4436     p->oops_do(f, cf);
4437   }
4438   VMThread::vm_thread()->oops_do(f, cf);
4439 }
4440 
4441 void Threads::change_thread_claim_parity() {
4442   // Set the new claim parity.
4443   assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4444          "Not in range.");
4445   _thread_claim_parity++;
4446   if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4447   assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4448          "Not in range.");
4449 }
4450 
4451 #ifdef ASSERT
4452 void Threads::assert_all_threads_claimed() {
4453   ALL_JAVA_THREADS(p) {
4454     const int thread_parity = p->oops_do_parity();
4455     assert((thread_parity == _thread_claim_parity),
4456            "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4457   }
4458   VMThread* vmt = VMThread::vm_thread();
4459   const int thread_parity = vmt->oops_do_parity();
4460   assert((thread_parity == _thread_claim_parity),
4461          "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4462 }
4463 #endif // ASSERT
4464 
4465 class ParallelOopsDoThreadClosure : public ThreadClosure {
4466 private:
4467   OopClosure* _f;
4468   CodeBlobClosure* _cf;
4469 public:
4470   ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4471   void do_thread(Thread* t) {
4472     t->oops_do(_f, _cf);
4473   }
4474 };
4475 
4476 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4477   ParallelOopsDoThreadClosure tc(f, cf);
4478   possibly_parallel_threads_do(is_par, &tc);
4479 }
4480 
4481 void Threads::nmethods_do(CodeBlobClosure* cf) {
4482   ALL_JAVA_THREADS(p) {
4483     // This is used by the code cache sweeper to mark nmethods that are active
4484     // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4485     // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4486     if(!p->is_Code_cache_sweeper_thread()) {
4487       p->nmethods_do(cf);
4488     }
4489   }
4490 }
4491 
4492 void Threads::metadata_do(void f(Metadata*)) {
4493   ALL_JAVA_THREADS(p) {
4494     p->metadata_do(f);
4495   }
4496 }
4497 
4498 class ThreadHandlesClosure : public ThreadClosure {
4499   void (*_f)(Metadata*);
4500  public:
4501   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4502   virtual void do_thread(Thread* thread) {
4503     thread->metadata_handles_do(_f);
4504   }
4505 };
4506 
4507 void Threads::metadata_handles_do(void f(Metadata*)) {
4508   // Only walk the Handles in Thread.
4509   ThreadHandlesClosure handles_closure(f);
4510   threads_do(&handles_closure);
4511 }
4512 
4513 void Threads::deoptimized_wrt_marked_nmethods() {
4514   ALL_JAVA_THREADS(p) {
4515     p->deoptimized_wrt_marked_nmethods();
4516   }
4517 }
4518 
4519 
4520 // Get count Java threads that are waiting to enter the specified monitor.
4521 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4522                                                          int count,
4523                                                          address monitor) {
4524   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4525 
4526   int i = 0;
4527   DO_JAVA_THREADS(t_list, p) {
4528     if (!p->can_call_java()) continue;
4529 
4530     address pending = (address)p->current_pending_monitor();
4531     if (pending == monitor) {             // found a match
4532       if (i < count) result->append(p);   // save the first count matches
4533       i++;
4534     }
4535   }
4536 
4537   return result;
4538 }
4539 
4540 
4541 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4542                                                       address owner) {
4543   // NULL owner means not locked so we can skip the search
4544   if (owner == NULL) return NULL;
4545 
4546   DO_JAVA_THREADS(t_list, p) {
4547     // first, see if owner is the address of a Java thread
4548     if (owner == (address)p) return p;
4549   }
4550 
4551   // Cannot assert on lack of success here since this function may be
4552   // used by code that is trying to report useful problem information
4553   // like deadlock detection.
4554   if (UseHeavyMonitors) return NULL;
4555 
4556   // If we didn't find a matching Java thread and we didn't force use of
4557   // heavyweight monitors, then the owner is the stack address of the
4558   // Lock Word in the owning Java thread's stack.
4559   //
4560   JavaThread* the_owner = NULL;
4561   DO_JAVA_THREADS(t_list, q) {
4562     if (q->is_lock_owned(owner)) {
4563       the_owner = q;
4564       break;
4565     }
4566   }
4567 
4568   // cannot assert on lack of success here; see above comment
4569   return the_owner;
4570 }
4571 
4572 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4573 void Threads::print_on(outputStream* st, bool print_stacks,
4574                        bool internal_format, bool print_concurrent_locks,
4575                        bool extended_thread_info) {
4576   char buf[32];
4577   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4578 
4579   st->print_cr("Full thread dump %s (%s %s):",
4580                Abstract_VM_Version::vm_name(),
4581                Abstract_VM_Version::vm_release(),
4582                Abstract_VM_Version::vm_info_string());
4583   st->cr();
4584 
4585 #if INCLUDE_SERVICES
4586   // Dump concurrent locks
4587   ConcurrentLocksDump concurrent_locks;
4588   if (print_concurrent_locks) {
4589     concurrent_locks.dump_at_safepoint();
4590   }
4591 #endif // INCLUDE_SERVICES
4592 
4593   ThreadsSMRSupport::print_info_on(st);
4594   st->cr();
4595 
4596   ALL_JAVA_THREADS(p) {
4597     ResourceMark rm;
4598     p->print_on(st, extended_thread_info);
4599     if (print_stacks) {
4600       if (internal_format) {
4601         p->trace_stack();
4602       } else {
4603         p->print_stack_on(st);
4604       }
4605     }
4606     st->cr();
4607 #if INCLUDE_SERVICES
4608     if (print_concurrent_locks) {
4609       concurrent_locks.print_locks_on(p, st);
4610     }
4611 #endif // INCLUDE_SERVICES
4612   }
4613 
4614   VMThread::vm_thread()->print_on(st);
4615   st->cr();
4616   Universe::heap()->print_gc_threads_on(st);
4617   WatcherThread* wt = WatcherThread::watcher_thread();
4618   if (wt != NULL) {
4619     wt->print_on(st);
4620     st->cr();
4621   }
4622 
4623   st->flush();
4624 }
4625 
4626 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4627                              int buflen, bool* found_current) {
4628   if (this_thread != NULL) {
4629     bool is_current = (current == this_thread);
4630     *found_current = *found_current || is_current;
4631     st->print("%s", is_current ? "=>" : "  ");
4632 
4633     st->print(PTR_FORMAT, p2i(this_thread));
4634     st->print(" ");
4635     this_thread->print_on_error(st, buf, buflen);
4636     st->cr();
4637   }
4638 }
4639 
4640 class PrintOnErrorClosure : public ThreadClosure {
4641   outputStream* _st;
4642   Thread* _current;
4643   char* _buf;
4644   int _buflen;
4645   bool* _found_current;
4646  public:
4647   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4648                       int buflen, bool* found_current) :
4649    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4650 
4651   virtual void do_thread(Thread* thread) {
4652     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4653   }
4654 };
4655 
4656 // Threads::print_on_error() is called by fatal error handler. It's possible
4657 // that VM is not at safepoint and/or current thread is inside signal handler.
4658 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4659 // memory (even in resource area), it might deadlock the error handler.
4660 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4661                              int buflen) {
4662   ThreadsSMRSupport::print_info_on(st);
4663   st->cr();
4664 
4665   bool found_current = false;
4666   st->print_cr("Java Threads: ( => current thread )");
4667   ALL_JAVA_THREADS(thread) {
4668     print_on_error(thread, st, current, buf, buflen, &found_current);
4669   }
4670   st->cr();
4671 
4672   st->print_cr("Other Threads:");
4673   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4674   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4675 
4676   PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4677   Universe::heap()->gc_threads_do(&print_closure);
4678 
4679   if (!found_current) {
4680     st->cr();
4681     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4682     current->print_on_error(st, buf, buflen);
4683     st->cr();
4684   }
4685   st->cr();
4686 
4687   st->print_cr("Threads with active compile tasks:");
4688   print_threads_compiling(st, buf, buflen);
4689 }
4690 
4691 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4692   ALL_JAVA_THREADS(thread) {
4693     if (thread->is_Compiler_thread()) {
4694       CompilerThread* ct = (CompilerThread*) thread;
4695 
4696       // Keep task in local variable for NULL check.
4697       // ct->_task might be set to NULL by concurring compiler thread
4698       // because it completed the compilation. The task is never freed,
4699       // though, just returned to a free list.
4700       CompileTask* task = ct->task();
4701       if (task != NULL) {
4702         thread->print_name_on_error(st, buf, buflen);
4703         task->print(st, NULL, true, true);
4704       }
4705     }
4706   }
4707 }
4708 
4709 
4710 // Internal SpinLock and Mutex
4711 // Based on ParkEvent
4712 
4713 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4714 //
4715 // We employ SpinLocks _only for low-contention, fixed-length
4716 // short-duration critical sections where we're concerned
4717 // about native mutex_t or HotSpot Mutex:: latency.
4718 // The mux construct provides a spin-then-block mutual exclusion
4719 // mechanism.
4720 //
4721 // Testing has shown that contention on the ListLock guarding gFreeList
4722 // is common.  If we implement ListLock as a simple SpinLock it's common
4723 // for the JVM to devolve to yielding with little progress.  This is true
4724 // despite the fact that the critical sections protected by ListLock are
4725 // extremely short.
4726 //
4727 // TODO-FIXME: ListLock should be of type SpinLock.
4728 // We should make this a 1st-class type, integrated into the lock
4729 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4730 // should have sufficient padding to avoid false-sharing and excessive
4731 // cache-coherency traffic.
4732 
4733 
4734 typedef volatile int SpinLockT;
4735 
4736 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4737   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4738     return;   // normal fast-path return
4739   }
4740 
4741   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4742   TEVENT(SpinAcquire - ctx);
4743   int ctr = 0;
4744   int Yields = 0;
4745   for (;;) {
4746     while (*adr != 0) {
4747       ++ctr;
4748       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4749         if (Yields > 5) {
4750           os::naked_short_sleep(1);
4751         } else {
4752           os::naked_yield();
4753           ++Yields;
4754         }
4755       } else {
4756         SpinPause();
4757       }
4758     }
4759     if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4760   }
4761 }
4762 
4763 void Thread::SpinRelease(volatile int * adr) {
4764   assert(*adr != 0, "invariant");
4765   OrderAccess::fence();      // guarantee at least release consistency.
4766   // Roach-motel semantics.
4767   // It's safe if subsequent LDs and STs float "up" into the critical section,
4768   // but prior LDs and STs within the critical section can't be allowed
4769   // to reorder or float past the ST that releases the lock.
4770   // Loads and stores in the critical section - which appear in program
4771   // order before the store that releases the lock - must also appear
4772   // before the store that releases the lock in memory visibility order.
4773   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4774   // the ST of 0 into the lock-word which releases the lock, so fence
4775   // more than covers this on all platforms.
4776   *adr = 0;
4777 }
4778 
4779 // muxAcquire and muxRelease:
4780 //
4781 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4782 //    The LSB of the word is set IFF the lock is held.
4783 //    The remainder of the word points to the head of a singly-linked list
4784 //    of threads blocked on the lock.
4785 //
4786 // *  The current implementation of muxAcquire-muxRelease uses its own
4787 //    dedicated Thread._MuxEvent instance.  If we're interested in
4788 //    minimizing the peak number of extant ParkEvent instances then
4789 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4790 //    as certain invariants were satisfied.  Specifically, care would need
4791 //    to be taken with regards to consuming unpark() "permits".
4792 //    A safe rule of thumb is that a thread would never call muxAcquire()
4793 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4794 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4795 //    consume an unpark() permit intended for monitorenter, for instance.
4796 //    One way around this would be to widen the restricted-range semaphore
4797 //    implemented in park().  Another alternative would be to provide
4798 //    multiple instances of the PlatformEvent() for each thread.  One
4799 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4800 //
4801 // *  Usage:
4802 //    -- Only as leaf locks
4803 //    -- for short-term locking only as muxAcquire does not perform
4804 //       thread state transitions.
4805 //
4806 // Alternatives:
4807 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4808 //    but with parking or spin-then-park instead of pure spinning.
4809 // *  Use Taura-Oyama-Yonenzawa locks.
4810 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4811 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4812 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4813 //    acquiring threads use timers (ParkTimed) to detect and recover from
4814 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4815 //    boundaries by using placement-new.
4816 // *  Augment MCS with advisory back-link fields maintained with CAS().
4817 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4818 //    The validity of the backlinks must be ratified before we trust the value.
4819 //    If the backlinks are invalid the exiting thread must back-track through the
4820 //    the forward links, which are always trustworthy.
4821 // *  Add a successor indication.  The LockWord is currently encoded as
4822 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4823 //    to provide the usual futile-wakeup optimization.
4824 //    See RTStt for details.
4825 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4826 //
4827 
4828 
4829 const intptr_t LOCKBIT = 1;
4830 
4831 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4832   intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4833   if (w == 0) return;
4834   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4835     return;
4836   }
4837 
4838   TEVENT(muxAcquire - Contention);
4839   ParkEvent * const Self = Thread::current()->_MuxEvent;
4840   assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4841   for (;;) {
4842     int its = (os::is_MP() ? 100 : 0) + 1;
4843 
4844     // Optional spin phase: spin-then-park strategy
4845     while (--its >= 0) {
4846       w = *Lock;
4847       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4848         return;
4849       }
4850     }
4851 
4852     Self->reset();
4853     Self->OnList = intptr_t(Lock);
4854     // The following fence() isn't _strictly necessary as the subsequent
4855     // CAS() both serializes execution and ratifies the fetched *Lock value.
4856     OrderAccess::fence();
4857     for (;;) {
4858       w = *Lock;
4859       if ((w & LOCKBIT) == 0) {
4860         if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4861           Self->OnList = 0;   // hygiene - allows stronger asserts
4862           return;
4863         }
4864         continue;      // Interference -- *Lock changed -- Just retry
4865       }
4866       assert(w & LOCKBIT, "invariant");
4867       Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4868       if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4869     }
4870 
4871     while (Self->OnList != 0) {
4872       Self->park();
4873     }
4874   }
4875 }
4876 
4877 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4878   intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4879   if (w == 0) return;
4880   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4881     return;
4882   }
4883 
4884   TEVENT(muxAcquire - Contention);
4885   ParkEvent * ReleaseAfter = NULL;
4886   if (ev == NULL) {
4887     ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4888   }
4889   assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4890   for (;;) {
4891     guarantee(ev->OnList == 0, "invariant");
4892     int its = (os::is_MP() ? 100 : 0) + 1;
4893 
4894     // Optional spin phase: spin-then-park strategy
4895     while (--its >= 0) {
4896       w = *Lock;
4897       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4898         if (ReleaseAfter != NULL) {
4899           ParkEvent::Release(ReleaseAfter);
4900         }
4901         return;
4902       }
4903     }
4904 
4905     ev->reset();
4906     ev->OnList = intptr_t(Lock);
4907     // The following fence() isn't _strictly necessary as the subsequent
4908     // CAS() both serializes execution and ratifies the fetched *Lock value.
4909     OrderAccess::fence();
4910     for (;;) {
4911       w = *Lock;
4912       if ((w & LOCKBIT) == 0) {
4913         if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4914           ev->OnList = 0;
4915           // We call ::Release while holding the outer lock, thus
4916           // artificially lengthening the critical section.
4917           // Consider deferring the ::Release() until the subsequent unlock(),
4918           // after we've dropped the outer lock.
4919           if (ReleaseAfter != NULL) {
4920             ParkEvent::Release(ReleaseAfter);
4921           }
4922           return;
4923         }
4924         continue;      // Interference -- *Lock changed -- Just retry
4925       }
4926       assert(w & LOCKBIT, "invariant");
4927       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4928       if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4929     }
4930 
4931     while (ev->OnList != 0) {
4932       ev->park();
4933     }
4934   }
4935 }
4936 
4937 // Release() must extract a successor from the list and then wake that thread.
4938 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4939 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4940 // Release() would :
4941 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4942 // (B) Extract a successor from the private list "in-hand"
4943 // (C) attempt to CAS() the residual back into *Lock over null.
4944 //     If there were any newly arrived threads and the CAS() would fail.
4945 //     In that case Release() would detach the RATs, re-merge the list in-hand
4946 //     with the RATs and repeat as needed.  Alternately, Release() might
4947 //     detach and extract a successor, but then pass the residual list to the wakee.
4948 //     The wakee would be responsible for reattaching and remerging before it
4949 //     competed for the lock.
4950 //
4951 // Both "pop" and DMR are immune from ABA corruption -- there can be
4952 // multiple concurrent pushers, but only one popper or detacher.
4953 // This implementation pops from the head of the list.  This is unfair,
4954 // but tends to provide excellent throughput as hot threads remain hot.
4955 // (We wake recently run threads first).
4956 //
4957 // All paths through muxRelease() will execute a CAS.
4958 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4959 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4960 // executed within the critical section are complete and globally visible before the
4961 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4962 void Thread::muxRelease(volatile intptr_t * Lock)  {
4963   for (;;) {
4964     const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4965     assert(w & LOCKBIT, "invariant");
4966     if (w == LOCKBIT) return;
4967     ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4968     assert(List != NULL, "invariant");
4969     assert(List->OnList == intptr_t(Lock), "invariant");
4970     ParkEvent * const nxt = List->ListNext;
4971     guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4972 
4973     // The following CAS() releases the lock and pops the head element.
4974     // The CAS() also ratifies the previously fetched lock-word value.
4975     if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4976       continue;
4977     }
4978     List->OnList = 0;
4979     OrderAccess::fence();
4980     List->unpark();
4981     return;
4982   }
4983 }
4984 
4985 
4986 void Threads::verify() {
4987   ALL_JAVA_THREADS(p) {
4988     p->verify();
4989   }
4990   VMThread* thread = VMThread::vm_thread();
4991   if (thread != NULL) thread->verify();
4992 }
--- EOF ---