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/gcId.hpp"
  37 #include "gc/shared/gcLocker.inline.hpp"
  38 #include "gc/shared/workgroup.hpp"
  39 #include "interpreter/interpreter.hpp"
  40 #include "interpreter/linkResolver.hpp"
  41 #include "interpreter/oopMapCache.hpp"
  42 #include "jvmtifiles/jvmtiEnv.hpp"
  43 #include "logging/log.hpp"
  44 #include "logging/logConfiguration.hpp"
  45 #include "logging/logStream.hpp"
  46 #include "memory/allocation.inline.hpp"
  47 #include "memory/metaspaceShared.hpp"
  48 #include "memory/oopFactory.hpp"
  49 #include "memory/resourceArea.hpp"
  50 #include "memory/universe.hpp"
  51 #include "oops/access.inline.hpp"
  52 #include "oops/instanceKlass.hpp"
  53 #include "oops/objArrayOop.hpp"
  54 #include "oops/oop.inline.hpp"
  55 #include "oops/symbol.hpp"
  56 #include "oops/typeArrayOop.inline.hpp"
  57 #include "oops/verifyOopClosure.hpp"
  58 #include "prims/jvm_misc.hpp"
  59 #include "prims/jvmtiExport.hpp"
  60 #include "prims/jvmtiThreadState.hpp"
  61 #include "prims/privilegedStack.hpp"
  62 #include "runtime/arguments.hpp"
  63 #include "runtime/atomic.hpp"
  64 #include "runtime/biasedLocking.hpp"
  65 #include "runtime/commandLineFlagConstraintList.hpp"
  66 #include "runtime/commandLineFlagWriteableList.hpp"
  67 #include "runtime/commandLineFlagRangeList.hpp"
  68 #include "runtime/deoptimization.hpp"
  69 #include "runtime/frame.inline.hpp"
  70 #include "runtime/globals.hpp"
  71 #include "runtime/handshake.hpp"
  72 #include "runtime/init.hpp"
  73 #include "runtime/interfaceSupport.inline.hpp"
  74 #include "runtime/java.hpp"
  75 #include "runtime/javaCalls.hpp"
  76 #include "runtime/jniHandles.inline.hpp"
  77 #include "runtime/jniPeriodicChecker.hpp"
  78 #include "runtime/memprofiler.hpp"
  79 #include "runtime/mutexLocker.hpp"
  80 #include "runtime/objectMonitor.hpp"
  81 #include "runtime/orderAccess.inline.hpp"
  82 #include "runtime/osThread.hpp"
  83 #include "runtime/prefetch.inline.hpp"
  84 #include "runtime/safepoint.hpp"
  85 #include "runtime/safepointMechanism.inline.hpp"
  86 #include "runtime/sharedRuntime.hpp"
  87 #include "runtime/statSampler.hpp"
  88 #include "runtime/stubRoutines.hpp"
  89 #include "runtime/sweeper.hpp"
  90 #include "runtime/task.hpp"
  91 #include "runtime/thread.inline.hpp"
  92 #include "runtime/threadCritical.hpp"
  93 #include "runtime/threadSMR.inline.hpp"
  94 #include "runtime/timer.hpp"
  95 #include "runtime/timerTrace.hpp"
  96 #include "runtime/vframe.inline.hpp"
  97 #include "runtime/vframeArray.hpp"
  98 #include "runtime/vframe_hp.hpp"
  99 #include "runtime/vmThread.hpp"
 100 #include "runtime/vm_operations.hpp"
 101 #include "runtime/vm_version.hpp"
 102 #include "services/attachListener.hpp"
 103 #include "services/management.hpp"
 104 #include "services/memTracker.hpp"
 105 #include "services/threadService.hpp"
 106 #include "trace/traceMacros.hpp"
 107 #include "trace/tracing.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_ALL_GCS
 117 #include "gc/cms/concurrentMarkSweepThread.hpp"
 118 #include "gc/g1/g1ConcurrentMarkThread.inline.hpp"
 119 #include "gc/parallel/pcTasks.hpp"
 120 #endif // INCLUDE_ALL_GCS
 121 #if INCLUDE_JVMCI
 122 #include "jvmci/jvmciCompiler.hpp"
 123 #include "jvmci/jvmciRuntime.hpp"
 124 #include "logging/logHandle.hpp"
 125 #endif
 126 #ifdef COMPILER1
 127 #include "c1/c1_Compiler.hpp"
 128 #endif
 129 #ifdef COMPILER2
 130 #include "opto/c2compiler.hpp"
 131 #include "opto/idealGraphPrinter.hpp"
 132 #endif
 133 #if INCLUDE_RTM_OPT
 134 #include "runtime/rtmLocking.hpp"
 135 #endif
 136 
 137 // Initialization after module runtime initialization
 138 void universe_post_module_init();  // must happen after call_initPhase2
 139 
 140 #ifdef DTRACE_ENABLED
 141 
 142 // Only bother with this argument setup if dtrace is available
 143 
 144   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 145   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 146 
 147   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 148     {                                                                      \
 149       ResourceMark rm(this);                                               \
 150       int len = 0;                                                         \
 151       const char* name = (javathread)->get_thread_name();                  \
 152       len = strlen(name);                                                  \
 153       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 154         (char *) name, len,                                                \
 155         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 156         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 157         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 158     }
 159 
 160 #else //  ndef DTRACE_ENABLED
 161 
 162   #define DTRACE_THREAD_PROBE(probe, javathread)
 163 
 164 #endif // ndef DTRACE_ENABLED
 165 
 166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 167 // Current thread is maintained as a thread-local variable
 168 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
 169 #endif
 170 // Class hierarchy
 171 // - Thread
 172 //   - VMThread
 173 //   - WatcherThread
 174 //   - ConcurrentMarkSweepThread
 175 //   - JavaThread
 176 //     - CompilerThread
 177 
 178 // ======= Thread ========
 179 // Support for forcing alignment of thread objects for biased locking
 180 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
 181   if (UseBiasedLocking) {
 182     const int alignment = markOopDesc::biased_lock_alignment;
 183     size_t aligned_size = size + (alignment - sizeof(intptr_t));
 184     void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
 185                                           : AllocateHeap(aligned_size, flags, CURRENT_PC,
 186                                                          AllocFailStrategy::RETURN_NULL);
 187     void* aligned_addr     = align_up(real_malloc_addr, alignment);
 188     assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
 189            ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
 190            "JavaThread alignment code overflowed allocated storage");
 191     if (aligned_addr != real_malloc_addr) {
 192       log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
 193                               p2i(real_malloc_addr),
 194                               p2i(aligned_addr));
 195     }
 196     ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
 197     return aligned_addr;
 198   } else {
 199     return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
 200                        : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 201   }
 202 }
 203 
 204 void Thread::operator delete(void* p) {
 205   if (UseBiasedLocking) {
 206     FreeHeap(((Thread*) p)->_real_malloc_address);
 207   } else {
 208     FreeHeap(p);
 209   }
 210 }
 211 
 212 void JavaThread::smr_delete() {
 213   if (_on_thread_list) {
 214     ThreadsSMRSupport::smr_delete(this);
 215   } else {
 216     delete this;
 217   }
 218 }
 219 
 220 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
 221 // JavaThread
 222 
 223 
 224 Thread::Thread() {
 225   // stack and get_thread
 226   set_stack_base(NULL);
 227   set_stack_size(0);
 228   set_self_raw_id(0);
 229   set_lgrp_id(-1);
 230   DEBUG_ONLY(clear_suspendible_thread();)
 231 
 232   // allocated data structures
 233   set_osthread(NULL);
 234   set_resource_area(new (mtThread)ResourceArea());
 235   DEBUG_ONLY(_current_resource_mark = NULL;)
 236   set_handle_area(new (mtThread) HandleArea(NULL));
 237   set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
 238   set_active_handles(NULL);
 239   set_free_handle_block(NULL);
 240   set_last_handle_mark(NULL);
 241 
 242   // This initial value ==> never claimed.
 243   _oops_do_parity = 0;
 244   _threads_hazard_ptr = NULL;
 245   _nested_threads_hazard_ptr = NULL;
 246   _nested_threads_hazard_ptr_cnt = 0;
 247 
 248   // the handle mark links itself to last_handle_mark
 249   new HandleMark(this);
 250 
 251   // plain initialization
 252   debug_only(_owned_locks = NULL;)
 253   debug_only(_allow_allocation_count = 0;)
 254   NOT_PRODUCT(_allow_safepoint_count = 0;)
 255   NOT_PRODUCT(_skip_gcalot = false;)
 256   _jvmti_env_iteration_count = 0;
 257   set_allocated_bytes(0);
 258   _vm_operation_started_count = 0;
 259   _vm_operation_completed_count = 0;
 260   _current_pending_monitor = NULL;
 261   _current_pending_monitor_is_from_java = true;
 262   _current_waiting_monitor = NULL;
 263   _num_nested_signal = 0;
 264   omFreeList = NULL;
 265   omFreeCount = 0;
 266   omFreeProvision = 32;
 267   omInUseList = NULL;
 268   omInUseCount = 0;
 269 
 270 #ifdef ASSERT
 271   _visited_for_critical_count = false;
 272 #endif
 273 
 274   _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
 275                          Monitor::_safepoint_check_sometimes);
 276   _suspend_flags = 0;
 277 
 278   // thread-specific hashCode stream generator state - Marsaglia shift-xor form
 279   _hashStateX = os::random();
 280   _hashStateY = 842502087;
 281   _hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
 282   _hashStateW = 273326509;
 283 
 284   _OnTrap   = 0;
 285   _schedctl = NULL;
 286   _Stalled  = 0;
 287   _TypeTag  = 0x2BAD;
 288 
 289   // Many of the following fields are effectively final - immutable
 290   // Note that nascent threads can't use the Native Monitor-Mutex
 291   // construct until the _MutexEvent is initialized ...
 292   // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
 293   // we might instead use a stack of ParkEvents that we could provision on-demand.
 294   // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
 295   // and ::Release()
 296   _ParkEvent   = ParkEvent::Allocate(this);
 297   _SleepEvent  = ParkEvent::Allocate(this);
 298   _MutexEvent  = ParkEvent::Allocate(this);
 299   _MuxEvent    = ParkEvent::Allocate(this);
 300 
 301 #ifdef CHECK_UNHANDLED_OOPS
 302   if (CheckUnhandledOops) {
 303     _unhandled_oops = new UnhandledOops(this);
 304   }
 305 #endif // CHECK_UNHANDLED_OOPS
 306 #ifdef ASSERT
 307   if (UseBiasedLocking) {
 308     assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
 309     assert(this == _real_malloc_address ||
 310            this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
 311            "bug in forced alignment of thread objects");
 312   }
 313 #endif // ASSERT
 314 }
 315 
 316 void Thread::initialize_thread_current() {
 317 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 318   assert(_thr_current == NULL, "Thread::current already initialized");
 319   _thr_current = this;
 320 #endif
 321   assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
 322   ThreadLocalStorage::set_thread(this);
 323   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 324 }
 325 
 326 void Thread::clear_thread_current() {
 327   assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
 328 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 329   _thr_current = NULL;
 330 #endif
 331   ThreadLocalStorage::set_thread(NULL);
 332 }
 333 
 334 void Thread::record_stack_base_and_size() {
 335   set_stack_base(os::current_stack_base());
 336   set_stack_size(os::current_stack_size());
 337   // CR 7190089: on Solaris, primordial thread's stack is adjusted
 338   // in initialize_thread(). Without the adjustment, stack size is
 339   // incorrect if stack is set to unlimited (ulimit -s unlimited).
 340   // So far, only Solaris has real implementation of initialize_thread().
 341   //
 342   // set up any platform-specific state.
 343   os::initialize_thread(this);
 344 
 345   // Set stack limits after thread is initialized.
 346   if (is_Java_thread()) {
 347     ((JavaThread*) this)->set_stack_overflow_limit();
 348     ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
 349   }
 350 #if INCLUDE_NMT
 351   // record thread's native stack, stack grows downward
 352   MemTracker::record_thread_stack(stack_end(), stack_size());
 353 #endif // INCLUDE_NMT
 354   log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
 355     PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
 356     os::current_thread_id(), p2i(stack_base() - stack_size()),
 357     p2i(stack_base()), stack_size()/1024);
 358 }
 359 
 360 
 361 Thread::~Thread() {
 362   EVENT_THREAD_DESTRUCT(this);
 363 
 364   // stack_base can be NULL if the thread is never started or exited before
 365   // record_stack_base_and_size called. Although, we would like to ensure
 366   // that all started threads do call record_stack_base_and_size(), there is
 367   // not proper way to enforce that.
 368 #if INCLUDE_NMT
 369   if (_stack_base != NULL) {
 370     MemTracker::release_thread_stack(stack_end(), stack_size());
 371 #ifdef ASSERT
 372     set_stack_base(NULL);
 373 #endif
 374   }
 375 #endif // INCLUDE_NMT
 376 
 377   // deallocate data structures
 378   delete resource_area();
 379   // since the handle marks are using the handle area, we have to deallocated the root
 380   // handle mark before deallocating the thread's handle area,
 381   assert(last_handle_mark() != NULL, "check we have an element");
 382   delete last_handle_mark();
 383   assert(last_handle_mark() == NULL, "check we have reached the end");
 384 
 385   // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
 386   // We NULL out the fields for good hygiene.
 387   ParkEvent::Release(_ParkEvent); _ParkEvent   = NULL;
 388   ParkEvent::Release(_SleepEvent); _SleepEvent  = NULL;
 389   ParkEvent::Release(_MutexEvent); _MutexEvent  = NULL;
 390   ParkEvent::Release(_MuxEvent); _MuxEvent    = NULL;
 391 
 392   delete handle_area();
 393   delete metadata_handles();
 394 
 395   // SR_handler uses this as a termination indicator -
 396   // needs to happen before os::free_thread()
 397   delete _SR_lock;
 398   _SR_lock = NULL;
 399 
 400   // osthread() can be NULL, if creation of thread failed.
 401   if (osthread() != NULL) os::free_thread(osthread());
 402 
 403   // clear Thread::current if thread is deleting itself.
 404   // Needed to ensure JNI correctly detects non-attached threads.
 405   if (this == Thread::current()) {
 406     clear_thread_current();
 407   }
 408 
 409   CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
 410 }
 411 
 412 // NOTE: dummy function for assertion purpose.
 413 void Thread::run() {
 414   ShouldNotReachHere();
 415 }
 416 
 417 #ifdef ASSERT
 418 // A JavaThread is considered "dangling" if it is not the current
 419 // thread, has been added the Threads list, the system is not at a
 420 // safepoint and the Thread is not "protected".
 421 //
 422 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
 423   assert(!thread->is_Java_thread() || Thread::current() == thread ||
 424          !((JavaThread *) thread)->on_thread_list() ||
 425          SafepointSynchronize::is_at_safepoint() ||
 426          ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
 427          "possibility of dangling Thread pointer");
 428 }
 429 #endif
 430 
 431 ThreadPriority Thread::get_priority(const Thread* const thread) {
 432   ThreadPriority priority;
 433   // Can return an error!
 434   (void)os::get_priority(thread, priority);
 435   assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
 436   return priority;
 437 }
 438 
 439 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
 440   debug_only(check_for_dangling_thread_pointer(thread);)
 441   // Can return an error!
 442   (void)os::set_priority(thread, priority);
 443 }
 444 
 445 
 446 void Thread::start(Thread* thread) {
 447   // Start is different from resume in that its safety is guaranteed by context or
 448   // being called from a Java method synchronized on the Thread object.
 449   if (!DisableStartThread) {
 450     if (thread->is_Java_thread()) {
 451       // Initialize the thread state to RUNNABLE before starting this thread.
 452       // Can not set it after the thread started because we do not know the
 453       // exact thread state at that time. It could be in MONITOR_WAIT or
 454       // in SLEEPING or some other state.
 455       java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
 456                                           java_lang_Thread::RUNNABLE);
 457     }
 458     os::start_thread(thread);
 459   }
 460 }
 461 
 462 // Enqueue a VM_Operation to do the job for us - sometime later
 463 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
 464   VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
 465   VMThread::execute(vm_stop);
 466 }
 467 
 468 
 469 // Check if an external suspend request has completed (or has been
 470 // cancelled). Returns true if the thread is externally suspended and
 471 // false otherwise.
 472 //
 473 // The bits parameter returns information about the code path through
 474 // the routine. Useful for debugging:
 475 //
 476 // set in is_ext_suspend_completed():
 477 // 0x00000001 - routine was entered
 478 // 0x00000010 - routine return false at end
 479 // 0x00000100 - thread exited (return false)
 480 // 0x00000200 - suspend request cancelled (return false)
 481 // 0x00000400 - thread suspended (return true)
 482 // 0x00001000 - thread is in a suspend equivalent state (return true)
 483 // 0x00002000 - thread is native and walkable (return true)
 484 // 0x00004000 - thread is native_trans and walkable (needed retry)
 485 //
 486 // set in wait_for_ext_suspend_completion():
 487 // 0x00010000 - routine was entered
 488 // 0x00020000 - suspend request cancelled before loop (return false)
 489 // 0x00040000 - thread suspended before loop (return true)
 490 // 0x00080000 - suspend request cancelled in loop (return false)
 491 // 0x00100000 - thread suspended in loop (return true)
 492 // 0x00200000 - suspend not completed during retry loop (return false)
 493 
 494 // Helper class for tracing suspend wait debug bits.
 495 //
 496 // 0x00000100 indicates that the target thread exited before it could
 497 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
 498 // 0x00080000 each indicate a cancelled suspend request so they don't
 499 // count as wait failures either.
 500 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
 501 
 502 class TraceSuspendDebugBits : public StackObj {
 503  private:
 504   JavaThread * jt;
 505   bool         is_wait;
 506   bool         called_by_wait;  // meaningful when !is_wait
 507   uint32_t *   bits;
 508 
 509  public:
 510   TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
 511                         uint32_t *_bits) {
 512     jt             = _jt;
 513     is_wait        = _is_wait;
 514     called_by_wait = _called_by_wait;
 515     bits           = _bits;
 516   }
 517 
 518   ~TraceSuspendDebugBits() {
 519     if (!is_wait) {
 520 #if 1
 521       // By default, don't trace bits for is_ext_suspend_completed() calls.
 522       // That trace is very chatty.
 523       return;
 524 #else
 525       if (!called_by_wait) {
 526         // If tracing for is_ext_suspend_completed() is enabled, then only
 527         // trace calls to it from wait_for_ext_suspend_completion()
 528         return;
 529       }
 530 #endif
 531     }
 532 
 533     if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
 534       if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
 535         MutexLocker ml(Threads_lock);  // needed for get_thread_name()
 536         ResourceMark rm;
 537 
 538         tty->print_cr(
 539                       "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
 540                       jt->get_thread_name(), *bits);
 541 
 542         guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
 543       }
 544     }
 545   }
 546 };
 547 #undef DEBUG_FALSE_BITS
 548 
 549 
 550 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
 551                                           uint32_t *bits) {
 552   TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
 553 
 554   bool did_trans_retry = false;  // only do thread_in_native_trans retry once
 555   bool do_trans_retry;           // flag to force the retry
 556 
 557   *bits |= 0x00000001;
 558 
 559   do {
 560     do_trans_retry = false;
 561 
 562     if (is_exiting()) {
 563       // Thread is in the process of exiting. This is always checked
 564       // first to reduce the risk of dereferencing a freed JavaThread.
 565       *bits |= 0x00000100;
 566       return false;
 567     }
 568 
 569     if (!is_external_suspend()) {
 570       // Suspend request is cancelled. This is always checked before
 571       // is_ext_suspended() to reduce the risk of a rogue resume
 572       // confusing the thread that made the suspend request.
 573       *bits |= 0x00000200;
 574       return false;
 575     }
 576 
 577     if (is_ext_suspended()) {
 578       // thread is suspended
 579       *bits |= 0x00000400;
 580       return true;
 581     }
 582 
 583     // Now that we no longer do hard suspends of threads running
 584     // native code, the target thread can be changing thread state
 585     // while we are in this routine:
 586     //
 587     //   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
 588     //
 589     // We save a copy of the thread state as observed at this moment
 590     // and make our decision about suspend completeness based on the
 591     // copy. This closes the race where the thread state is seen as
 592     // _thread_in_native_trans in the if-thread_blocked check, but is
 593     // seen as _thread_blocked in if-thread_in_native_trans check.
 594     JavaThreadState save_state = thread_state();
 595 
 596     if (save_state == _thread_blocked && is_suspend_equivalent()) {
 597       // If the thread's state is _thread_blocked and this blocking
 598       // condition is known to be equivalent to a suspend, then we can
 599       // consider the thread to be externally suspended. This means that
 600       // the code that sets _thread_blocked has been modified to do
 601       // self-suspension if the blocking condition releases. We also
 602       // used to check for CONDVAR_WAIT here, but that is now covered by
 603       // the _thread_blocked with self-suspension check.
 604       //
 605       // Return true since we wouldn't be here unless there was still an
 606       // external suspend request.
 607       *bits |= 0x00001000;
 608       return true;
 609     } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
 610       // Threads running native code will self-suspend on native==>VM/Java
 611       // transitions. If its stack is walkable (should always be the case
 612       // unless this function is called before the actual java_suspend()
 613       // call), then the wait is done.
 614       *bits |= 0x00002000;
 615       return true;
 616     } else if (!called_by_wait && !did_trans_retry &&
 617                save_state == _thread_in_native_trans &&
 618                frame_anchor()->walkable()) {
 619       // The thread is transitioning from thread_in_native to another
 620       // thread state. check_safepoint_and_suspend_for_native_trans()
 621       // will force the thread to self-suspend. If it hasn't gotten
 622       // there yet we may have caught the thread in-between the native
 623       // code check above and the self-suspend. Lucky us. If we were
 624       // called by wait_for_ext_suspend_completion(), then it
 625       // will be doing the retries so we don't have to.
 626       //
 627       // Since we use the saved thread state in the if-statement above,
 628       // there is a chance that the thread has already transitioned to
 629       // _thread_blocked by the time we get here. In that case, we will
 630       // make a single unnecessary pass through the logic below. This
 631       // doesn't hurt anything since we still do the trans retry.
 632 
 633       *bits |= 0x00004000;
 634 
 635       // Once the thread leaves thread_in_native_trans for another
 636       // thread state, we break out of this retry loop. We shouldn't
 637       // need this flag to prevent us from getting back here, but
 638       // sometimes paranoia is good.
 639       did_trans_retry = true;
 640 
 641       // We wait for the thread to transition to a more usable state.
 642       for (int i = 1; i <= SuspendRetryCount; i++) {
 643         // We used to do an "os::yield_all(i)" call here with the intention
 644         // that yielding would increase on each retry. However, the parameter
 645         // is ignored on Linux which means the yield didn't scale up. Waiting
 646         // on the SR_lock below provides a much more predictable scale up for
 647         // the delay. It also provides a simple/direct point to check for any
 648         // safepoint requests from the VMThread
 649 
 650         // temporarily drops SR_lock while doing wait with safepoint check
 651         // (if we're a JavaThread - the WatcherThread can also call this)
 652         // and increase delay with each retry
 653         SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 654 
 655         // check the actual thread state instead of what we saved above
 656         if (thread_state() != _thread_in_native_trans) {
 657           // the thread has transitioned to another thread state so
 658           // try all the checks (except this one) one more time.
 659           do_trans_retry = true;
 660           break;
 661         }
 662       } // end retry loop
 663 
 664 
 665     }
 666   } while (do_trans_retry);
 667 
 668   *bits |= 0x00000010;
 669   return false;
 670 }
 671 
 672 // Wait for an external suspend request to complete (or be cancelled).
 673 // Returns true if the thread is externally suspended and false otherwise.
 674 //
 675 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
 676                                                  uint32_t *bits) {
 677   TraceSuspendDebugBits tsdb(this, true /* is_wait */,
 678                              false /* !called_by_wait */, bits);
 679 
 680   // local flag copies to minimize SR_lock hold time
 681   bool is_suspended;
 682   bool pending;
 683   uint32_t reset_bits;
 684 
 685   // set a marker so is_ext_suspend_completed() knows we are the caller
 686   *bits |= 0x00010000;
 687 
 688   // We use reset_bits to reinitialize the bits value at the top of
 689   // each retry loop. This allows the caller to make use of any
 690   // unused bits for their own marking purposes.
 691   reset_bits = *bits;
 692 
 693   {
 694     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 695     is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 696                                             delay, bits);
 697     pending = is_external_suspend();
 698   }
 699   // must release SR_lock to allow suspension to complete
 700 
 701   if (!pending) {
 702     // A cancelled suspend request is the only false return from
 703     // is_ext_suspend_completed() that keeps us from entering the
 704     // retry loop.
 705     *bits |= 0x00020000;
 706     return false;
 707   }
 708 
 709   if (is_suspended) {
 710     *bits |= 0x00040000;
 711     return true;
 712   }
 713 
 714   for (int i = 1; i <= retries; i++) {
 715     *bits = reset_bits;  // reinit to only track last retry
 716 
 717     // We used to do an "os::yield_all(i)" call here with the intention
 718     // that yielding would increase on each retry. However, the parameter
 719     // is ignored on Linux which means the yield didn't scale up. Waiting
 720     // on the SR_lock below provides a much more predictable scale up for
 721     // the delay. It also provides a simple/direct point to check for any
 722     // safepoint requests from the VMThread
 723 
 724     {
 725       MutexLocker ml(SR_lock());
 726       // wait with safepoint check (if we're a JavaThread - the WatcherThread
 727       // can also call this)  and increase delay with each retry
 728       SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
 729 
 730       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
 731                                               delay, bits);
 732 
 733       // It is possible for the external suspend request to be cancelled
 734       // (by a resume) before the actual suspend operation is completed.
 735       // Refresh our local copy to see if we still need to wait.
 736       pending = is_external_suspend();
 737     }
 738 
 739     if (!pending) {
 740       // A cancelled suspend request is the only false return from
 741       // is_ext_suspend_completed() that keeps us from staying in the
 742       // retry loop.
 743       *bits |= 0x00080000;
 744       return false;
 745     }
 746 
 747     if (is_suspended) {
 748       *bits |= 0x00100000;
 749       return true;
 750     }
 751   } // end retry loop
 752 
 753   // thread did not suspend after all our retries
 754   *bits |= 0x00200000;
 755   return false;
 756 }
 757 
 758 // Called from API entry points which perform stack walking. If the
 759 // associated JavaThread is the current thread, then wait_for_suspend
 760 // is not used. Otherwise, it determines if we should wait for the
 761 // "other" thread to complete external suspension. (NOTE: in future
 762 // releases the suspension mechanism should be reimplemented so this
 763 // is not necessary.)
 764 //
 765 bool
 766 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
 767   if (this != JavaThread::current()) {
 768     // "other" threads require special handling.
 769     if (wait_for_suspend) {
 770       // We are allowed to wait for the external suspend to complete
 771       // so give the other thread a chance to get suspended.
 772       if (!wait_for_ext_suspend_completion(SuspendRetryCount,
 773                                            SuspendRetryDelay, bits)) {
 774         // Didn't make it so let the caller know.
 775         return false;
 776       }
 777     }
 778     // We aren't allowed to wait for the external suspend to complete
 779     // so if the other thread isn't externally suspended we need to
 780     // let the caller know.
 781     else if (!is_ext_suspend_completed_with_lock(bits)) {
 782       return false;
 783     }
 784   }
 785 
 786   return true;
 787 }
 788 
 789 #ifndef PRODUCT
 790 void JavaThread::record_jump(address target, address instr, const char* file,
 791                              int line) {
 792 
 793   // This should not need to be atomic as the only way for simultaneous
 794   // updates is via interrupts. Even then this should be rare or non-existent
 795   // and we don't care that much anyway.
 796 
 797   int index = _jmp_ring_index;
 798   _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
 799   _jmp_ring[index]._target = (intptr_t) target;
 800   _jmp_ring[index]._instruction = (intptr_t) instr;
 801   _jmp_ring[index]._file = file;
 802   _jmp_ring[index]._line = line;
 803 }
 804 #endif // PRODUCT
 805 
 806 void Thread::interrupt(Thread* thread) {
 807   debug_only(check_for_dangling_thread_pointer(thread);)
 808   os::interrupt(thread);
 809 }
 810 
 811 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
 812   debug_only(check_for_dangling_thread_pointer(thread);)
 813   // Note:  If clear_interrupted==false, this simply fetches and
 814   // returns the value of the field osthread()->interrupted().
 815   return os::is_interrupted(thread, clear_interrupted);
 816 }
 817 
 818 
 819 // GC Support
 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
 821   int thread_parity = _oops_do_parity;
 822   if (thread_parity != strong_roots_parity) {
 823     jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
 824     if (res == thread_parity) {
 825       return true;
 826     } else {
 827       guarantee(res == strong_roots_parity, "Or else what?");
 828       return false;
 829     }
 830   }
 831   return false;
 832 }
 833 
 834 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
 835   active_handles()->oops_do(f);
 836   // Do oop for ThreadShadow
 837   f->do_oop((oop*)&_pending_exception);
 838   handle_area()->oops_do(f);
 839 
 840   if (MonitorInUseLists) {
 841     // When using thread local monitor lists, we scan them here,
 842     // and the remaining global monitors in ObjectSynchronizer::oops_do().
 843     ObjectSynchronizer::thread_local_used_oops_do(this, f);
 844   }
 845 }
 846 
 847 void Thread::metadata_handles_do(void f(Metadata*)) {
 848   // Only walk the Handles in Thread.
 849   if (metadata_handles() != NULL) {
 850     for (int i = 0; i< metadata_handles()->length(); i++) {
 851       f(metadata_handles()->at(i));
 852     }
 853   }
 854 }
 855 
 856 void Thread::print_on(outputStream* st) const {
 857   // get_priority assumes osthread initialized
 858   if (osthread() != NULL) {
 859     int os_prio;
 860     if (os::get_native_priority(this, &os_prio) == OS_OK) {
 861       st->print("os_prio=%d ", os_prio);
 862     }
 863     st->print("tid=" INTPTR_FORMAT " ", p2i(this));
 864     osthread()->print_on(st);
 865   }
 866   if (_threads_hazard_ptr != NULL) {
 867     st->print("_threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
 868   }
 869   if (_nested_threads_hazard_ptr != NULL) {
 870     print_nested_threads_hazard_ptrs_on(st);
 871   }
 872   st->print(" ");
 873   debug_only(if (WizardMode) print_owned_locks_on(st);)
 874 }
 875 
 876 void Thread::print_nested_threads_hazard_ptrs_on(outputStream* st) const {
 877   assert(_nested_threads_hazard_ptr != NULL, "must be set to print");
 878 
 879   if (EnableThreadSMRStatistics) {
 880     st->print(", _nested_threads_hazard_ptr_cnt=%u", _nested_threads_hazard_ptr_cnt);
 881   }
 882   st->print(", _nested_threads_hazard_ptrs=");
 883   for (NestedThreadsList* node = _nested_threads_hazard_ptr; node != NULL;
 884        node = node->next()) {
 885     if (node != _nested_threads_hazard_ptr) {
 886       // First node does not need a comma-space separator.
 887       st->print(", ");
 888     }
 889     st->print(INTPTR_FORMAT, p2i(node->t_list()));
 890   }
 891 }
 892 
 893 // Thread::print_on_error() is called by fatal error handler. Don't use
 894 // any lock or allocate memory.
 895 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
 896   assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
 897 
 898   if (is_VM_thread())                 { st->print("VMThread"); }
 899   else if (is_GC_task_thread())       { st->print("GCTaskThread"); }
 900   else if (is_Watcher_thread())       { st->print("WatcherThread"); }
 901   else if (is_ConcurrentGC_thread())  { st->print("ConcurrentGCThread"); }
 902   else                                { st->print("Thread"); }
 903 
 904   if (is_Named_thread()) {
 905     st->print(" \"%s\"", name());
 906   }
 907 
 908   st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
 909             p2i(stack_end()), p2i(stack_base()));
 910 
 911   if (osthread()) {
 912     st->print(" [id=%d]", osthread()->thread_id());
 913   }
 914 
 915   if (_threads_hazard_ptr != NULL) {
 916     st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
 917   }
 918   if (_nested_threads_hazard_ptr != NULL) {
 919     print_nested_threads_hazard_ptrs_on(st);
 920   }
 921 }
 922 
 923 void Thread::print_value_on(outputStream* st) const {
 924   if (is_Named_thread()) {
 925     st->print(" \"%s\" ", name());
 926   }
 927   st->print(INTPTR_FORMAT, p2i(this));   // print address
 928 }
 929 
 930 #ifdef ASSERT
 931 void Thread::print_owned_locks_on(outputStream* st) const {
 932   Monitor *cur = _owned_locks;
 933   if (cur == NULL) {
 934     st->print(" (no locks) ");
 935   } else {
 936     st->print_cr(" Locks owned:");
 937     while (cur) {
 938       cur->print_on(st);
 939       cur = cur->next();
 940     }
 941   }
 942 }
 943 
 944 static int ref_use_count  = 0;
 945 
 946 bool Thread::owns_locks_but_compiled_lock() const {
 947   for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 948     if (cur != Compile_lock) return true;
 949   }
 950   return false;
 951 }
 952 
 953 
 954 #endif
 955 
 956 #ifndef PRODUCT
 957 
 958 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
 959 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
 960 // no threads which allow_vm_block's are held
 961 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
 962   // Check if current thread is allowed to block at a safepoint
 963   if (!(_allow_safepoint_count == 0)) {
 964     fatal("Possible safepoint reached by thread that does not allow it");
 965   }
 966   if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
 967     fatal("LEAF method calling lock?");
 968   }
 969 
 970 #ifdef ASSERT
 971   if (potential_vm_operation && is_Java_thread()
 972       && !Universe::is_bootstrapping()) {
 973     // Make sure we do not hold any locks that the VM thread also uses.
 974     // This could potentially lead to deadlocks
 975     for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
 976       // Threads_lock is special, since the safepoint synchronization will not start before this is
 977       // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
 978       // since it is used to transfer control between JavaThreads and the VMThread
 979       // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
 980       if ((cur->allow_vm_block() &&
 981            cur != Threads_lock &&
 982            cur != Compile_lock &&               // Temporary: should not be necessary when we get separate compilation
 983            cur != VMOperationRequest_lock &&
 984            cur != VMOperationQueue_lock) ||
 985            cur->rank() == Mutex::special) {
 986         fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
 987       }
 988     }
 989   }
 990 
 991   if (GCALotAtAllSafepoints) {
 992     // We could enter a safepoint here and thus have a gc
 993     InterfaceSupport::check_gc_alot();
 994   }
 995 #endif
 996 }
 997 #endif
 998 
 999 bool Thread::is_in_stack(address adr) const {
1000   assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1001   address end = os::current_stack_pointer();
1002   // Allow non Java threads to call this without stack_base
1003   if (_stack_base == NULL) return true;
1004   if (stack_base() >= adr && adr >= end) return true;
1005 
1006   return false;
1007 }
1008 
1009 bool Thread::is_in_usable_stack(address adr) const {
1010   size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1011   size_t usable_stack_size = _stack_size - stack_guard_size;
1012 
1013   return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1014 }
1015 
1016 
1017 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1018 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1019 // used for compilation in the future. If that change is made, the need for these methods
1020 // should be revisited, and they should be removed if possible.
1021 
1022 bool Thread::is_lock_owned(address adr) const {
1023   return on_local_stack(adr);
1024 }
1025 
1026 bool Thread::set_as_starting_thread() {
1027   // NOTE: this must be called inside the main thread.
1028   return os::create_main_thread((JavaThread*)this);
1029 }
1030 
1031 static void initialize_class(Symbol* class_name, TRAPS) {
1032   Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1033   InstanceKlass::cast(klass)->initialize(CHECK);
1034 }
1035 
1036 
1037 // Creates the initial ThreadGroup
1038 static Handle create_initial_thread_group(TRAPS) {
1039   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1040   InstanceKlass* ik = InstanceKlass::cast(k);
1041 
1042   Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
1043   {
1044     JavaValue result(T_VOID);
1045     JavaCalls::call_special(&result,
1046                             system_instance,
1047                             ik,
1048                             vmSymbols::object_initializer_name(),
1049                             vmSymbols::void_method_signature(),
1050                             CHECK_NH);
1051   }
1052   Universe::set_system_thread_group(system_instance());
1053 
1054   Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
1055   {
1056     JavaValue result(T_VOID);
1057     Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1058     JavaCalls::call_special(&result,
1059                             main_instance,
1060                             ik,
1061                             vmSymbols::object_initializer_name(),
1062                             vmSymbols::threadgroup_string_void_signature(),
1063                             system_instance,
1064                             string,
1065                             CHECK_NH);
1066   }
1067   return main_instance;
1068 }
1069 
1070 // Creates the initial Thread
1071 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1072                                  TRAPS) {
1073   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1074   InstanceKlass* ik = InstanceKlass::cast(k);
1075   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1076 
1077   java_lang_Thread::set_thread(thread_oop(), thread);
1078   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1079   thread->set_threadObj(thread_oop());
1080 
1081   Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1082 
1083   JavaValue result(T_VOID);
1084   JavaCalls::call_special(&result, thread_oop,
1085                           ik,
1086                           vmSymbols::object_initializer_name(),
1087                           vmSymbols::threadgroup_string_void_signature(),
1088                           thread_group,
1089                           string,
1090                           CHECK_NULL);
1091   return thread_oop();
1092 }
1093 
1094 char java_runtime_name[128] = "";
1095 char java_runtime_version[128] = "";
1096 
1097 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1098 static const char* get_java_runtime_name(TRAPS) {
1099   Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1100                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1101   fieldDescriptor fd;
1102   bool found = k != NULL &&
1103                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1104                                                         vmSymbols::string_signature(), &fd);
1105   if (found) {
1106     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1107     if (name_oop == NULL) {
1108       return NULL;
1109     }
1110     const char* name = java_lang_String::as_utf8_string(name_oop,
1111                                                         java_runtime_name,
1112                                                         sizeof(java_runtime_name));
1113     return name;
1114   } else {
1115     return NULL;
1116   }
1117 }
1118 
1119 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1120 static const char* get_java_runtime_version(TRAPS) {
1121   Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1122                                     Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1123   fieldDescriptor fd;
1124   bool found = k != NULL &&
1125                InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1126                                                         vmSymbols::string_signature(), &fd);
1127   if (found) {
1128     oop name_oop = k->java_mirror()->obj_field(fd.offset());
1129     if (name_oop == NULL) {
1130       return NULL;
1131     }
1132     const char* name = java_lang_String::as_utf8_string(name_oop,
1133                                                         java_runtime_version,
1134                                                         sizeof(java_runtime_version));
1135     return name;
1136   } else {
1137     return NULL;
1138   }
1139 }
1140 
1141 // General purpose hook into Java code, run once when the VM is initialized.
1142 // The Java library method itself may be changed independently from the VM.
1143 static void call_postVMInitHook(TRAPS) {
1144   Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1145   if (klass != NULL) {
1146     JavaValue result(T_VOID);
1147     JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1148                            vmSymbols::void_method_signature(),
1149                            CHECK);
1150   }
1151 }
1152 
1153 static void reset_vm_info_property(TRAPS) {
1154   // the vm info string
1155   ResourceMark rm(THREAD);
1156   const char *vm_info = VM_Version::vm_info_string();
1157 
1158   // java.lang.System class
1159   Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1160 
1161   // setProperty arguments
1162   Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
1163   Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
1164 
1165   // return value
1166   JavaValue r(T_OBJECT);
1167 
1168   // public static String setProperty(String key, String value);
1169   JavaCalls::call_static(&r,
1170                          klass,
1171                          vmSymbols::setProperty_name(),
1172                          vmSymbols::string_string_string_signature(),
1173                          key_str,
1174                          value_str,
1175                          CHECK);
1176 }
1177 
1178 
1179 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1180                                     bool daemon, TRAPS) {
1181   assert(thread_group.not_null(), "thread group should be specified");
1182   assert(threadObj() == NULL, "should only create Java thread object once");
1183 
1184   Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1185   InstanceKlass* ik = InstanceKlass::cast(k);
1186   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1187 
1188   java_lang_Thread::set_thread(thread_oop(), this);
1189   java_lang_Thread::set_priority(thread_oop(), NormPriority);
1190   set_threadObj(thread_oop());
1191 
1192   JavaValue result(T_VOID);
1193   if (thread_name != NULL) {
1194     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1195     // Thread gets assigned specified name and null target
1196     JavaCalls::call_special(&result,
1197                             thread_oop,
1198                             ik,
1199                             vmSymbols::object_initializer_name(),
1200                             vmSymbols::threadgroup_string_void_signature(),
1201                             thread_group, // Argument 1
1202                             name,         // Argument 2
1203                             THREAD);
1204   } else {
1205     // Thread gets assigned name "Thread-nnn" and null target
1206     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1207     JavaCalls::call_special(&result,
1208                             thread_oop,
1209                             ik,
1210                             vmSymbols::object_initializer_name(),
1211                             vmSymbols::threadgroup_runnable_void_signature(),
1212                             thread_group, // Argument 1
1213                             Handle(),     // Argument 2
1214                             THREAD);
1215   }
1216 
1217 
1218   if (daemon) {
1219     java_lang_Thread::set_daemon(thread_oop());
1220   }
1221 
1222   if (HAS_PENDING_EXCEPTION) {
1223     return;
1224   }
1225 
1226   Klass* group =  SystemDictionary::ThreadGroup_klass();
1227   Handle threadObj(THREAD, this->threadObj());
1228 
1229   JavaCalls::call_special(&result,
1230                           thread_group,
1231                           group,
1232                           vmSymbols::add_method_name(),
1233                           vmSymbols::thread_void_signature(),
1234                           threadObj,          // Arg 1
1235                           THREAD);
1236 }
1237 
1238 // NamedThread --  non-JavaThread subclasses with multiple
1239 // uniquely named instances should derive from this.
1240 NamedThread::NamedThread() : Thread() {
1241   _name = NULL;
1242   _processed_thread = NULL;
1243   _gc_id = GCId::undefined();
1244 }
1245 
1246 NamedThread::~NamedThread() {
1247   if (_name != NULL) {
1248     FREE_C_HEAP_ARRAY(char, _name);
1249     _name = NULL;
1250   }
1251 }
1252 
1253 void NamedThread::set_name(const char* format, ...) {
1254   guarantee(_name == NULL, "Only get to set name once.");
1255   _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1256   guarantee(_name != NULL, "alloc failure");
1257   va_list ap;
1258   va_start(ap, format);
1259   jio_vsnprintf(_name, max_name_len, format, ap);
1260   va_end(ap);
1261 }
1262 
1263 void NamedThread::initialize_named_thread() {
1264   set_native_thread_name(name());
1265 }
1266 
1267 void NamedThread::print_on(outputStream* st) const {
1268   st->print("\"%s\" ", name());
1269   Thread::print_on(st);
1270   st->cr();
1271 }
1272 
1273 
1274 // ======= WatcherThread ========
1275 
1276 // The watcher thread exists to simulate timer interrupts.  It should
1277 // be replaced by an abstraction over whatever native support for
1278 // timer interrupts exists on the platform.
1279 
1280 WatcherThread* WatcherThread::_watcher_thread   = NULL;
1281 bool WatcherThread::_startable = false;
1282 volatile bool  WatcherThread::_should_terminate = false;
1283 
1284 WatcherThread::WatcherThread() : Thread() {
1285   assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1286   if (os::create_thread(this, os::watcher_thread)) {
1287     _watcher_thread = this;
1288 
1289     // Set the watcher thread to the highest OS priority which should not be
1290     // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1291     // is created. The only normal thread using this priority is the reference
1292     // handler thread, which runs for very short intervals only.
1293     // If the VMThread's priority is not lower than the WatcherThread profiling
1294     // will be inaccurate.
1295     os::set_priority(this, MaxPriority);
1296     if (!DisableStartThread) {
1297       os::start_thread(this);
1298     }
1299   }
1300 }
1301 
1302 int WatcherThread::sleep() const {
1303   // The WatcherThread does not participate in the safepoint protocol
1304   // for the PeriodicTask_lock because it is not a JavaThread.
1305   MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1306 
1307   if (_should_terminate) {
1308     // check for termination before we do any housekeeping or wait
1309     return 0;  // we did not sleep.
1310   }
1311 
1312   // remaining will be zero if there are no tasks,
1313   // causing the WatcherThread to sleep until a task is
1314   // enrolled
1315   int remaining = PeriodicTask::time_to_wait();
1316   int time_slept = 0;
1317 
1318   // we expect this to timeout - we only ever get unparked when
1319   // we should terminate or when a new task has been enrolled
1320   OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1321 
1322   jlong time_before_loop = os::javaTimeNanos();
1323 
1324   while (true) {
1325     bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1326                                             remaining);
1327     jlong now = os::javaTimeNanos();
1328 
1329     if (remaining == 0) {
1330       // if we didn't have any tasks we could have waited for a long time
1331       // consider the time_slept zero and reset time_before_loop
1332       time_slept = 0;
1333       time_before_loop = now;
1334     } else {
1335       // need to recalculate since we might have new tasks in _tasks
1336       time_slept = (int) ((now - time_before_loop) / 1000000);
1337     }
1338 
1339     // Change to task list or spurious wakeup of some kind
1340     if (timedout || _should_terminate) {
1341       break;
1342     }
1343 
1344     remaining = PeriodicTask::time_to_wait();
1345     if (remaining == 0) {
1346       // Last task was just disenrolled so loop around and wait until
1347       // another task gets enrolled
1348       continue;
1349     }
1350 
1351     remaining -= time_slept;
1352     if (remaining <= 0) {
1353       break;
1354     }
1355   }
1356 
1357   return time_slept;
1358 }
1359 
1360 void WatcherThread::run() {
1361   assert(this == watcher_thread(), "just checking");
1362 
1363   this->record_stack_base_and_size();
1364   this->set_native_thread_name(this->name());
1365   this->set_active_handles(JNIHandleBlock::allocate_block());
1366   while (true) {
1367     assert(watcher_thread() == Thread::current(), "thread consistency check");
1368     assert(watcher_thread() == this, "thread consistency check");
1369 
1370     // Calculate how long it'll be until the next PeriodicTask work
1371     // should be done, and sleep that amount of time.
1372     int time_waited = sleep();
1373 
1374     if (VMError::is_error_reported()) {
1375       // A fatal error has happened, the error handler(VMError::report_and_die)
1376       // should abort JVM after creating an error log file. However in some
1377       // rare cases, the error handler itself might deadlock. Here periodically
1378       // check for error reporting timeouts, and if it happens, just proceed to
1379       // abort the VM.
1380 
1381       // This code is in WatcherThread because WatcherThread wakes up
1382       // periodically so the fatal error handler doesn't need to do anything;
1383       // also because the WatcherThread is less likely to crash than other
1384       // threads.
1385 
1386       for (;;) {
1387         // Note: we use naked sleep in this loop because we want to avoid using
1388         // any kind of VM infrastructure which may be broken at this point.
1389         if (VMError::check_timeout()) {
1390           // We hit error reporting timeout. Error reporting was interrupted and
1391           // will be wrapping things up now (closing files etc). Give it some more
1392           // time, then quit the VM.
1393           os::naked_short_sleep(200);
1394           // Print a message to stderr.
1395           fdStream err(defaultStream::output_fd());
1396           err.print_raw_cr("# [ timer expired, abort... ]");
1397           // skip atexit/vm_exit/vm_abort hooks
1398           os::die();
1399         }
1400 
1401         // Wait a second, then recheck for timeout.
1402         os::naked_short_sleep(999);
1403       }
1404     }
1405 
1406     if (_should_terminate) {
1407       // check for termination before posting the next tick
1408       break;
1409     }
1410 
1411     PeriodicTask::real_time_tick(time_waited);
1412   }
1413 
1414   // Signal that it is terminated
1415   {
1416     MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1417     _watcher_thread = NULL;
1418     Terminator_lock->notify();
1419   }
1420 }
1421 
1422 void WatcherThread::start() {
1423   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1424 
1425   if (watcher_thread() == NULL && _startable) {
1426     _should_terminate = false;
1427     // Create the single instance of WatcherThread
1428     new WatcherThread();
1429   }
1430 }
1431 
1432 void WatcherThread::make_startable() {
1433   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1434   _startable = true;
1435 }
1436 
1437 void WatcherThread::stop() {
1438   {
1439     // Follow normal safepoint aware lock enter protocol since the
1440     // WatcherThread is stopped by another JavaThread.
1441     MutexLocker ml(PeriodicTask_lock);
1442     _should_terminate = true;
1443 
1444     WatcherThread* watcher = watcher_thread();
1445     if (watcher != NULL) {
1446       // unpark the WatcherThread so it can see that it should terminate
1447       watcher->unpark();
1448     }
1449   }
1450 
1451   MutexLocker mu(Terminator_lock);
1452 
1453   while (watcher_thread() != NULL) {
1454     // This wait should make safepoint checks, wait without a timeout,
1455     // and wait as a suspend-equivalent condition.
1456     Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1457                           Mutex::_as_suspend_equivalent_flag);
1458   }
1459 }
1460 
1461 void WatcherThread::unpark() {
1462   assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1463   PeriodicTask_lock->notify();
1464 }
1465 
1466 void WatcherThread::print_on(outputStream* st) const {
1467   st->print("\"%s\" ", name());
1468   Thread::print_on(st);
1469   st->cr();
1470 }
1471 
1472 // ======= JavaThread ========
1473 
1474 #if INCLUDE_JVMCI
1475 
1476 jlong* JavaThread::_jvmci_old_thread_counters;
1477 
1478 bool jvmci_counters_include(JavaThread* thread) {
1479   oop threadObj = thread->threadObj();
1480   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1481 }
1482 
1483 void JavaThread::collect_counters(typeArrayOop array) {
1484   if (JVMCICounterSize > 0) {
1485     MutexLocker tl(Threads_lock);
1486     JavaThreadIteratorWithHandle jtiwh;
1487     for (int i = 0; i < array->length(); i++) {
1488       array->long_at_put(i, _jvmci_old_thread_counters[i]);
1489     }
1490     for (; JavaThread *tp = jtiwh.next(); ) {
1491       if (jvmci_counters_include(tp)) {
1492         for (int i = 0; i < array->length(); i++) {
1493           array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1494         }
1495       }
1496     }
1497   }
1498 }
1499 
1500 #endif // INCLUDE_JVMCI
1501 
1502 // A JavaThread is a normal Java thread
1503 
1504 void JavaThread::initialize() {
1505   // Initialize fields
1506 
1507   set_saved_exception_pc(NULL);
1508   set_threadObj(NULL);
1509   _anchor.clear();
1510   set_entry_point(NULL);
1511   set_jni_functions(jni_functions());
1512   set_callee_target(NULL);
1513   set_vm_result(NULL);
1514   set_vm_result_2(NULL);
1515   set_vframe_array_head(NULL);
1516   set_vframe_array_last(NULL);
1517   set_deferred_locals(NULL);
1518   set_deopt_mark(NULL);
1519   set_deopt_compiled_method(NULL);
1520   clear_must_deopt_id();
1521   set_monitor_chunks(NULL);
1522   set_next(NULL);
1523   _on_thread_list = false;
1524   set_thread_state(_thread_new);
1525   _terminated = _not_terminated;
1526   _privileged_stack_top = NULL;
1527   _array_for_gc = NULL;
1528   _suspend_equivalent = false;
1529   _in_deopt_handler = 0;
1530   _doing_unsafe_access = false;
1531   _stack_guard_state = stack_guard_unused;
1532 #if INCLUDE_JVMCI
1533   _pending_monitorenter = false;
1534   _pending_deoptimization = -1;
1535   _pending_failed_speculation = NULL;
1536   _pending_transfer_to_interpreter = false;
1537   _adjusting_comp_level = false;
1538   _jvmci._alternate_call_target = NULL;
1539   assert(_jvmci._implicit_exception_pc == NULL, "must be");
1540   if (JVMCICounterSize > 0) {
1541     _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1542     memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1543   } else {
1544     _jvmci_counters = NULL;
1545   }
1546 #endif // INCLUDE_JVMCI
1547   _reserved_stack_activation = NULL;  // stack base not known yet
1548   (void)const_cast<oop&>(_exception_oop = oop(NULL));
1549   _exception_pc  = 0;
1550   _exception_handler_pc = 0;
1551   _is_method_handle_return = 0;
1552   _jvmti_thread_state= NULL;
1553   _should_post_on_exceptions_flag = JNI_FALSE;
1554   _jvmti_get_loaded_classes_closure = NULL;
1555   _interp_only_mode    = 0;
1556   _special_runtime_exit_condition = _no_async_condition;
1557   _pending_async_exception = NULL;
1558   _thread_stat = NULL;
1559   _thread_stat = new ThreadStatistics();
1560   _blocked_on_compilation = false;
1561   _jni_active_critical = 0;
1562   _pending_jni_exception_check_fn = NULL;
1563   _do_not_unlock_if_synchronized = false;
1564   _cached_monitor_info = NULL;
1565   _parker = Parker::Allocate(this);
1566 
1567 #ifndef PRODUCT
1568   _jmp_ring_index = 0;
1569   for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1570     record_jump(NULL, NULL, NULL, 0);
1571   }
1572 #endif // PRODUCT
1573 
1574   // Setup safepoint state info for this thread
1575   ThreadSafepointState::create(this);
1576 
1577   debug_only(_java_call_counter = 0);
1578 
1579   // JVMTI PopFrame support
1580   _popframe_condition = popframe_inactive;
1581   _popframe_preserved_args = NULL;
1582   _popframe_preserved_args_size = 0;
1583   _frames_to_pop_failed_realloc = 0;
1584 
1585   if (SafepointMechanism::uses_thread_local_poll()) {
1586     SafepointMechanism::initialize_header(this);
1587   }
1588 
1589   pd_initialize();
1590 }
1591 
1592 #if INCLUDE_ALL_GCS
1593 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1594 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1595 #endif // INCLUDE_ALL_GCS
1596 
1597 JavaThread::JavaThread(bool is_attaching_via_jni) :
1598                        Thread()
1599 #if INCLUDE_ALL_GCS
1600                        , _satb_mark_queue(&_satb_mark_queue_set),
1601                        _dirty_card_queue(&_dirty_card_queue_set)
1602 #endif // INCLUDE_ALL_GCS
1603 {
1604   initialize();
1605   if (is_attaching_via_jni) {
1606     _jni_attach_state = _attaching_via_jni;
1607   } else {
1608     _jni_attach_state = _not_attaching_via_jni;
1609   }
1610   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1611 }
1612 
1613 bool JavaThread::reguard_stack(address cur_sp) {
1614   if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1615       && _stack_guard_state != stack_guard_reserved_disabled) {
1616     return true; // Stack already guarded or guard pages not needed.
1617   }
1618 
1619   if (register_stack_overflow()) {
1620     // For those architectures which have separate register and
1621     // memory stacks, we must check the register stack to see if
1622     // it has overflowed.
1623     return false;
1624   }
1625 
1626   // Java code never executes within the yellow zone: the latter is only
1627   // there to provoke an exception during stack banging.  If java code
1628   // is executing there, either StackShadowPages should be larger, or
1629   // some exception code in c1, c2 or the interpreter isn't unwinding
1630   // when it should.
1631   guarantee(cur_sp > stack_reserved_zone_base(),
1632             "not enough space to reguard - increase StackShadowPages");
1633   if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1634     enable_stack_yellow_reserved_zone();
1635     if (reserved_stack_activation() != stack_base()) {
1636       set_reserved_stack_activation(stack_base());
1637     }
1638   } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1639     set_reserved_stack_activation(stack_base());
1640     enable_stack_reserved_zone();
1641   }
1642   return true;
1643 }
1644 
1645 bool JavaThread::reguard_stack(void) {
1646   return reguard_stack(os::current_stack_pointer());
1647 }
1648 
1649 
1650 void JavaThread::block_if_vm_exited() {
1651   if (_terminated == _vm_exited) {
1652     // _vm_exited is set at safepoint, and Threads_lock is never released
1653     // we will block here forever
1654     Threads_lock->lock_without_safepoint_check();
1655     ShouldNotReachHere();
1656   }
1657 }
1658 
1659 
1660 // Remove this ifdef when C1 is ported to the compiler interface.
1661 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1662 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1663 
1664 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1665                        Thread()
1666 #if INCLUDE_ALL_GCS
1667                        , _satb_mark_queue(&_satb_mark_queue_set),
1668                        _dirty_card_queue(&_dirty_card_queue_set)
1669 #endif // INCLUDE_ALL_GCS
1670 {
1671   initialize();
1672   _jni_attach_state = _not_attaching_via_jni;
1673   set_entry_point(entry_point);
1674   // Create the native thread itself.
1675   // %note runtime_23
1676   os::ThreadType thr_type = os::java_thread;
1677   thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1678                                                      os::java_thread;
1679   os::create_thread(this, thr_type, stack_sz);
1680   // The _osthread may be NULL here because we ran out of memory (too many threads active).
1681   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1682   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1683   // the exception consists of creating the exception object & initializing it, initialization
1684   // will leave the VM via a JavaCall and then all locks must be unlocked).
1685   //
1686   // The thread is still suspended when we reach here. Thread must be explicit started
1687   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1688   // by calling Threads:add. The reason why this is not done here, is because the thread
1689   // object must be fully initialized (take a look at JVM_Start)
1690 }
1691 
1692 JavaThread::~JavaThread() {
1693 
1694   // JSR166 -- return the parker to the free list
1695   Parker::Release(_parker);
1696   _parker = NULL;
1697 
1698   // Free any remaining  previous UnrollBlock
1699   vframeArray* old_array = vframe_array_last();
1700 
1701   if (old_array != NULL) {
1702     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1703     old_array->set_unroll_block(NULL);
1704     delete old_info;
1705     delete old_array;
1706   }
1707 
1708   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1709   if (deferred != NULL) {
1710     // This can only happen if thread is destroyed before deoptimization occurs.
1711     assert(deferred->length() != 0, "empty array!");
1712     do {
1713       jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1714       deferred->remove_at(0);
1715       // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1716       delete dlv;
1717     } while (deferred->length() != 0);
1718     delete deferred;
1719   }
1720 
1721   // All Java related clean up happens in exit
1722   ThreadSafepointState::destroy(this);
1723   if (_thread_stat != NULL) delete _thread_stat;
1724 
1725 #if INCLUDE_JVMCI
1726   if (JVMCICounterSize > 0) {
1727     if (jvmci_counters_include(this)) {
1728       for (int i = 0; i < JVMCICounterSize; i++) {
1729         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1730       }
1731     }
1732     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1733   }
1734 #endif // INCLUDE_JVMCI
1735 }
1736 
1737 
1738 // The first routine called by a new Java thread
1739 void JavaThread::run() {
1740   // initialize thread-local alloc buffer related fields
1741   this->initialize_tlab();
1742 
1743   // used to test validity of stack trace backs
1744   this->record_base_of_stack_pointer();
1745 
1746   // Record real stack base and size.
1747   this->record_stack_base_and_size();
1748 
1749   this->create_stack_guard_pages();
1750 
1751   this->cache_global_variables();
1752 
1753   // Thread is now sufficient initialized to be handled by the safepoint code as being
1754   // in the VM. Change thread state from _thread_new to _thread_in_vm
1755   ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1756 
1757   assert(JavaThread::current() == this, "sanity check");
1758   assert(!Thread::current()->owns_locks(), "sanity check");
1759 
1760   DTRACE_THREAD_PROBE(start, this);
1761 
1762   // This operation might block. We call that after all safepoint checks for a new thread has
1763   // been completed.
1764   this->set_active_handles(JNIHandleBlock::allocate_block());
1765 
1766   if (JvmtiExport::should_post_thread_life()) {
1767     JvmtiExport::post_thread_start(this);
1768   }
1769 
1770   EventThreadStart event;
1771   if (event.should_commit()) {
1772     event.set_thread(THREAD_TRACE_ID(this));
1773     event.commit();
1774   }
1775 
1776   // We call another function to do the rest so we are sure that the stack addresses used
1777   // from there will be lower than the stack base just computed
1778   thread_main_inner();
1779 
1780   // Note, thread is no longer valid at this point!
1781 }
1782 
1783 
1784 void JavaThread::thread_main_inner() {
1785   assert(JavaThread::current() == this, "sanity check");
1786   assert(this->threadObj() != NULL, "just checking");
1787 
1788   // Execute thread entry point unless this thread has a pending exception
1789   // or has been stopped before starting.
1790   // Note: Due to JVM_StopThread we can have pending exceptions already!
1791   if (!this->has_pending_exception() &&
1792       !java_lang_Thread::is_stillborn(this->threadObj())) {
1793     {
1794       ResourceMark rm(this);
1795       this->set_native_thread_name(this->get_thread_name());
1796     }
1797     HandleMark hm(this);
1798     this->entry_point()(this, this);
1799   }
1800 
1801   DTRACE_THREAD_PROBE(stop, this);
1802 
1803   this->exit(false);
1804   this->smr_delete();
1805 }
1806 
1807 
1808 static void ensure_join(JavaThread* thread) {
1809   // We do not need to grab the Threads_lock, since we are operating on ourself.
1810   Handle threadObj(thread, thread->threadObj());
1811   assert(threadObj.not_null(), "java thread object must exist");
1812   ObjectLocker lock(threadObj, thread);
1813   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1814   thread->clear_pending_exception();
1815   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
1816   java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1817   // Clear the native thread instance - this makes isAlive return false and allows the join()
1818   // to complete once we've done the notify_all below
1819   java_lang_Thread::set_thread(threadObj(), NULL);
1820   lock.notify_all(thread);
1821   // Ignore pending exception (ThreadDeath), since we are exiting anyway
1822   thread->clear_pending_exception();
1823 }
1824 
1825 
1826 // For any new cleanup additions, please check to see if they need to be applied to
1827 // cleanup_failed_attach_current_thread as well.
1828 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1829   assert(this == JavaThread::current(), "thread consistency check");
1830 
1831   elapsedTimer _timer_exit_phase1;
1832   elapsedTimer _timer_exit_phase2;
1833   elapsedTimer _timer_exit_phase3;
1834   elapsedTimer _timer_exit_phase4;
1835 
1836   if (log_is_enabled(Debug, os, thread, timer)) {
1837     _timer_exit_phase1.start();
1838   }
1839 
1840   HandleMark hm(this);
1841   Handle uncaught_exception(this, this->pending_exception());
1842   this->clear_pending_exception();
1843   Handle threadObj(this, this->threadObj());
1844   assert(threadObj.not_null(), "Java thread object should be created");
1845 
1846   // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1847   {
1848     EXCEPTION_MARK;
1849 
1850     CLEAR_PENDING_EXCEPTION;
1851   }
1852   if (!destroy_vm) {
1853     if (uncaught_exception.not_null()) {
1854       EXCEPTION_MARK;
1855       // Call method Thread.dispatchUncaughtException().
1856       Klass* thread_klass = SystemDictionary::Thread_klass();
1857       JavaValue result(T_VOID);
1858       JavaCalls::call_virtual(&result,
1859                               threadObj, thread_klass,
1860                               vmSymbols::dispatchUncaughtException_name(),
1861                               vmSymbols::throwable_void_signature(),
1862                               uncaught_exception,
1863                               THREAD);
1864       if (HAS_PENDING_EXCEPTION) {
1865         ResourceMark rm(this);
1866         jio_fprintf(defaultStream::error_stream(),
1867                     "\nException: %s thrown from the UncaughtExceptionHandler"
1868                     " in thread \"%s\"\n",
1869                     pending_exception()->klass()->external_name(),
1870                     get_thread_name());
1871         CLEAR_PENDING_EXCEPTION;
1872       }
1873     }
1874 
1875     // Called before the java thread exit since we want to read info
1876     // from java_lang_Thread object
1877     EventThreadEnd event;
1878     if (event.should_commit()) {
1879       event.set_thread(THREAD_TRACE_ID(this));
1880       event.commit();
1881     }
1882 
1883     // Call after last event on thread
1884     EVENT_THREAD_EXIT(this);
1885 
1886     // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1887     // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1888     // is deprecated anyhow.
1889     if (!is_Compiler_thread()) {
1890       int count = 3;
1891       while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1892         EXCEPTION_MARK;
1893         JavaValue result(T_VOID);
1894         Klass* thread_klass = SystemDictionary::Thread_klass();
1895         JavaCalls::call_virtual(&result,
1896                                 threadObj, thread_klass,
1897                                 vmSymbols::exit_method_name(),
1898                                 vmSymbols::void_method_signature(),
1899                                 THREAD);
1900         CLEAR_PENDING_EXCEPTION;
1901       }
1902     }
1903     // notify JVMTI
1904     if (JvmtiExport::should_post_thread_life()) {
1905       JvmtiExport::post_thread_end(this);
1906     }
1907 
1908     // We have notified the agents that we are exiting, before we go on,
1909     // we must check for a pending external suspend request and honor it
1910     // in order to not surprise the thread that made the suspend request.
1911     while (true) {
1912       {
1913         MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1914         if (!is_external_suspend()) {
1915           set_terminated(_thread_exiting);
1916           ThreadService::current_thread_exiting(this);
1917           break;
1918         }
1919         // Implied else:
1920         // Things get a little tricky here. We have a pending external
1921         // suspend request, but we are holding the SR_lock so we
1922         // can't just self-suspend. So we temporarily drop the lock
1923         // and then self-suspend.
1924       }
1925 
1926       ThreadBlockInVM tbivm(this);
1927       java_suspend_self();
1928 
1929       // We're done with this suspend request, but we have to loop around
1930       // and check again. Eventually we will get SR_lock without a pending
1931       // external suspend request and will be able to mark ourselves as
1932       // exiting.
1933     }
1934     // no more external suspends are allowed at this point
1935   } else {
1936     // before_exit() has already posted JVMTI THREAD_END events
1937   }
1938 
1939   if (log_is_enabled(Debug, os, thread, timer)) {
1940     _timer_exit_phase1.stop();
1941     _timer_exit_phase2.start();
1942   }
1943   // Notify waiters on thread object. This has to be done after exit() is called
1944   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1945   // group should have the destroyed bit set before waiters are notified).
1946   ensure_join(this);
1947   assert(!this->has_pending_exception(), "ensure_join should have cleared");
1948 
1949   if (log_is_enabled(Debug, os, thread, timer)) {
1950     _timer_exit_phase2.stop();
1951     _timer_exit_phase3.start();
1952   }
1953   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1954   // held by this thread must be released. The spec does not distinguish
1955   // between JNI-acquired and regular Java monitors. We can only see
1956   // regular Java monitors here if monitor enter-exit matching is broken.
1957   //
1958   // Optionally release any monitors for regular JavaThread exits. This
1959   // is provided as a work around for any bugs in monitor enter-exit
1960   // matching. This can be expensive so it is not enabled by default.
1961   //
1962   // ensure_join() ignores IllegalThreadStateExceptions, and so does
1963   // ObjectSynchronizer::release_monitors_owned_by_thread().
1964   if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1965     // Sanity check even though JNI DetachCurrentThread() would have
1966     // returned JNI_ERR if there was a Java frame. JavaThread exit
1967     // should be done executing Java code by the time we get here.
1968     assert(!this->has_last_Java_frame(),
1969            "should not have a Java frame when detaching or exiting");
1970     ObjectSynchronizer::release_monitors_owned_by_thread(this);
1971     assert(!this->has_pending_exception(), "release_monitors should have cleared");
1972   }
1973 
1974   // These things needs to be done while we are still a Java Thread. Make sure that thread
1975   // is in a consistent state, in case GC happens
1976   assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1977 
1978   if (active_handles() != NULL) {
1979     JNIHandleBlock* block = active_handles();
1980     set_active_handles(NULL);
1981     JNIHandleBlock::release_block(block);
1982   }
1983 
1984   if (free_handle_block() != NULL) {
1985     JNIHandleBlock* block = free_handle_block();
1986     set_free_handle_block(NULL);
1987     JNIHandleBlock::release_block(block);
1988   }
1989 
1990   // These have to be removed while this is still a valid thread.
1991   remove_stack_guard_pages();
1992 
1993   if (UseTLAB) {
1994     tlab().make_parsable(true);  // retire TLAB
1995   }
1996 
1997   if (JvmtiEnv::environments_might_exist()) {
1998     JvmtiExport::cleanup_thread(this);
1999   }
2000 
2001   // We must flush any deferred card marks and other various GC barrier
2002   // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2003   // before removing a thread from the list of active threads.
2004   BarrierSet::barrier_set()->on_thread_detach(this);
2005 
2006   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2007     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2008     os::current_thread_id());
2009 
2010   if (log_is_enabled(Debug, os, thread, timer)) {
2011     _timer_exit_phase3.stop();
2012     _timer_exit_phase4.start();
2013   }
2014   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2015   Threads::remove(this);
2016 
2017   if (log_is_enabled(Debug, os, thread, timer)) {
2018     _timer_exit_phase4.stop();
2019     ResourceMark rm(this);
2020     log_debug(os, thread, timer)("name='%s'"
2021                                  ", exit-phase1=" JLONG_FORMAT
2022                                  ", exit-phase2=" JLONG_FORMAT
2023                                  ", exit-phase3=" JLONG_FORMAT
2024                                  ", exit-phase4=" JLONG_FORMAT,
2025                                  get_thread_name(),
2026                                  _timer_exit_phase1.milliseconds(),
2027                                  _timer_exit_phase2.milliseconds(),
2028                                  _timer_exit_phase3.milliseconds(),
2029                                  _timer_exit_phase4.milliseconds());
2030   }
2031 }
2032 
2033 void JavaThread::cleanup_failed_attach_current_thread() {
2034   if (active_handles() != NULL) {
2035     JNIHandleBlock* block = active_handles();
2036     set_active_handles(NULL);
2037     JNIHandleBlock::release_block(block);
2038   }
2039 
2040   if (free_handle_block() != NULL) {
2041     JNIHandleBlock* block = free_handle_block();
2042     set_free_handle_block(NULL);
2043     JNIHandleBlock::release_block(block);
2044   }
2045 
2046   // These have to be removed while this is still a valid thread.
2047   remove_stack_guard_pages();
2048 
2049   if (UseTLAB) {
2050     tlab().make_parsable(true);  // retire TLAB, if any
2051   }
2052 
2053   BarrierSet::barrier_set()->on_thread_detach(this);
2054 
2055   Threads::remove(this);
2056   this->smr_delete();
2057 }
2058 
2059 JavaThread* JavaThread::active() {
2060   Thread* thread = Thread::current();
2061   if (thread->is_Java_thread()) {
2062     return (JavaThread*) thread;
2063   } else {
2064     assert(thread->is_VM_thread(), "this must be a vm thread");
2065     VM_Operation* op = ((VMThread*) thread)->vm_operation();
2066     JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2067     assert(ret->is_Java_thread(), "must be a Java thread");
2068     return ret;
2069   }
2070 }
2071 
2072 bool JavaThread::is_lock_owned(address adr) const {
2073   if (Thread::is_lock_owned(adr)) return true;
2074 
2075   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2076     if (chunk->contains(adr)) return true;
2077   }
2078 
2079   return false;
2080 }
2081 
2082 
2083 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2084   chunk->set_next(monitor_chunks());
2085   set_monitor_chunks(chunk);
2086 }
2087 
2088 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2089   guarantee(monitor_chunks() != NULL, "must be non empty");
2090   if (monitor_chunks() == chunk) {
2091     set_monitor_chunks(chunk->next());
2092   } else {
2093     MonitorChunk* prev = monitor_chunks();
2094     while (prev->next() != chunk) prev = prev->next();
2095     prev->set_next(chunk->next());
2096   }
2097 }
2098 
2099 // JVM support.
2100 
2101 // Note: this function shouldn't block if it's called in
2102 // _thread_in_native_trans state (such as from
2103 // check_special_condition_for_native_trans()).
2104 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2105 
2106   if (has_last_Java_frame() && has_async_condition()) {
2107     // If we are at a polling page safepoint (not a poll return)
2108     // then we must defer async exception because live registers
2109     // will be clobbered by the exception path. Poll return is
2110     // ok because the call we a returning from already collides
2111     // with exception handling registers and so there is no issue.
2112     // (The exception handling path kills call result registers but
2113     //  this is ok since the exception kills the result anyway).
2114 
2115     if (is_at_poll_safepoint()) {
2116       // if the code we are returning to has deoptimized we must defer
2117       // the exception otherwise live registers get clobbered on the
2118       // exception path before deoptimization is able to retrieve them.
2119       //
2120       RegisterMap map(this, false);
2121       frame caller_fr = last_frame().sender(&map);
2122       assert(caller_fr.is_compiled_frame(), "what?");
2123       if (caller_fr.is_deoptimized_frame()) {
2124         log_info(exceptions)("deferred async exception at compiled safepoint");
2125         return;
2126       }
2127     }
2128   }
2129 
2130   JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2131   if (condition == _no_async_condition) {
2132     // Conditions have changed since has_special_runtime_exit_condition()
2133     // was called:
2134     // - if we were here only because of an external suspend request,
2135     //   then that was taken care of above (or cancelled) so we are done
2136     // - if we were here because of another async request, then it has
2137     //   been cleared between the has_special_runtime_exit_condition()
2138     //   and now so again we are done
2139     return;
2140   }
2141 
2142   // Check for pending async. exception
2143   if (_pending_async_exception != NULL) {
2144     // Only overwrite an already pending exception, if it is not a threadDeath.
2145     if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2146 
2147       // We cannot call Exceptions::_throw(...) here because we cannot block
2148       set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2149 
2150       LogTarget(Info, exceptions) lt;
2151       if (lt.is_enabled()) {
2152         ResourceMark rm;
2153         LogStream ls(lt);
2154         ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2155           if (has_last_Java_frame()) {
2156             frame f = last_frame();
2157            ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2158           }
2159         ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2160       }
2161       _pending_async_exception = NULL;
2162       clear_has_async_exception();
2163     }
2164   }
2165 
2166   if (check_unsafe_error &&
2167       condition == _async_unsafe_access_error && !has_pending_exception()) {
2168     condition = _no_async_condition;  // done
2169     switch (thread_state()) {
2170     case _thread_in_vm: {
2171       JavaThread* THREAD = this;
2172       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2173     }
2174     case _thread_in_native: {
2175       ThreadInVMfromNative tiv(this);
2176       JavaThread* THREAD = this;
2177       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2178     }
2179     case _thread_in_Java: {
2180       ThreadInVMfromJava tiv(this);
2181       JavaThread* THREAD = this;
2182       THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2183     }
2184     default:
2185       ShouldNotReachHere();
2186     }
2187   }
2188 
2189   assert(condition == _no_async_condition || has_pending_exception() ||
2190          (!check_unsafe_error && condition == _async_unsafe_access_error),
2191          "must have handled the async condition, if no exception");
2192 }
2193 
2194 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2195   //
2196   // Check for pending external suspend. Internal suspend requests do
2197   // not use handle_special_runtime_exit_condition().
2198   // If JNIEnv proxies are allowed, don't self-suspend if the target
2199   // thread is not the current thread. In older versions of jdbx, jdbx
2200   // threads could call into the VM with another thread's JNIEnv so we
2201   // can be here operating on behalf of a suspended thread (4432884).
2202   bool do_self_suspend = is_external_suspend_with_lock();
2203   if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2204     //
2205     // Because thread is external suspended the safepoint code will count
2206     // thread as at a safepoint. This can be odd because we can be here
2207     // as _thread_in_Java which would normally transition to _thread_blocked
2208     // at a safepoint. We would like to mark the thread as _thread_blocked
2209     // before calling java_suspend_self like all other callers of it but
2210     // we must then observe proper safepoint protocol. (We can't leave
2211     // _thread_blocked with a safepoint in progress). However we can be
2212     // here as _thread_in_native_trans so we can't use a normal transition
2213     // constructor/destructor pair because they assert on that type of
2214     // transition. We could do something like:
2215     //
2216     // JavaThreadState state = thread_state();
2217     // set_thread_state(_thread_in_vm);
2218     // {
2219     //   ThreadBlockInVM tbivm(this);
2220     //   java_suspend_self()
2221     // }
2222     // set_thread_state(_thread_in_vm_trans);
2223     // if (safepoint) block;
2224     // set_thread_state(state);
2225     //
2226     // but that is pretty messy. Instead we just go with the way the
2227     // code has worked before and note that this is the only path to
2228     // java_suspend_self that doesn't put the thread in _thread_blocked
2229     // mode.
2230 
2231     frame_anchor()->make_walkable(this);
2232     java_suspend_self();
2233 
2234     // We might be here for reasons in addition to the self-suspend request
2235     // so check for other async requests.
2236   }
2237 
2238   if (check_asyncs) {
2239     check_and_handle_async_exceptions();
2240   }
2241 #if INCLUDE_TRACE
2242   if (is_trace_suspend()) {
2243     TRACE_SUSPEND_THREAD(this);
2244   }
2245 #endif
2246 }
2247 
2248 void JavaThread::send_thread_stop(oop java_throwable)  {
2249   assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2250   assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2251   assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2252 
2253   // Do not throw asynchronous exceptions against the compiler thread
2254   // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2255   if (!can_call_java()) return;
2256 
2257   {
2258     // Actually throw the Throwable against the target Thread - however
2259     // only if there is no thread death exception installed already.
2260     if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2261       // If the topmost frame is a runtime stub, then we are calling into
2262       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2263       // must deoptimize the caller before continuing, as the compiled  exception handler table
2264       // may not be valid
2265       if (has_last_Java_frame()) {
2266         frame f = last_frame();
2267         if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2268           // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2269           RegisterMap reg_map(this, UseBiasedLocking);
2270           frame compiled_frame = f.sender(&reg_map);
2271           if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2272             Deoptimization::deoptimize(this, compiled_frame, &reg_map);
2273           }
2274         }
2275       }
2276 
2277       // Set async. pending exception in thread.
2278       set_pending_async_exception(java_throwable);
2279 
2280       if (log_is_enabled(Info, exceptions)) {
2281          ResourceMark rm;
2282         log_info(exceptions)("Pending Async. exception installed of type: %s",
2283                              InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2284       }
2285       // for AbortVMOnException flag
2286       Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2287     }
2288   }
2289 
2290 
2291   // Interrupt thread so it will wake up from a potential wait()
2292   Thread::interrupt(this);
2293 }
2294 
2295 // External suspension mechanism.
2296 //
2297 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2298 // to any VM_locks and it is at a transition
2299 // Self-suspension will happen on the transition out of the vm.
2300 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2301 //
2302 // Guarantees on return:
2303 //   + Target thread will not execute any new bytecode (that's why we need to
2304 //     force a safepoint)
2305 //   + Target thread will not enter any new monitors
2306 //
2307 void JavaThread::java_suspend() {
2308   ThreadsListHandle tlh;
2309   if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2310     return;
2311   }
2312 
2313   { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2314     if (!is_external_suspend()) {
2315       // a racing resume has cancelled us; bail out now
2316       return;
2317     }
2318 
2319     // suspend is done
2320     uint32_t debug_bits = 0;
2321     // Warning: is_ext_suspend_completed() may temporarily drop the
2322     // SR_lock to allow the thread to reach a stable thread state if
2323     // it is currently in a transient thread state.
2324     if (is_ext_suspend_completed(false /* !called_by_wait */,
2325                                  SuspendRetryDelay, &debug_bits)) {
2326       return;
2327     }
2328   }
2329 
2330   VM_ThreadSuspend vm_suspend;
2331   VMThread::execute(&vm_suspend);
2332 }
2333 
2334 // Part II of external suspension.
2335 // A JavaThread self suspends when it detects a pending external suspend
2336 // request. This is usually on transitions. It is also done in places
2337 // where continuing to the next transition would surprise the caller,
2338 // e.g., monitor entry.
2339 //
2340 // Returns the number of times that the thread self-suspended.
2341 //
2342 // Note: DO NOT call java_suspend_self() when you just want to block current
2343 //       thread. java_suspend_self() is the second stage of cooperative
2344 //       suspension for external suspend requests and should only be used
2345 //       to complete an external suspend request.
2346 //
2347 int JavaThread::java_suspend_self() {
2348   int ret = 0;
2349 
2350   // we are in the process of exiting so don't suspend
2351   if (is_exiting()) {
2352     clear_external_suspend();
2353     return ret;
2354   }
2355 
2356   assert(_anchor.walkable() ||
2357          (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2358          "must have walkable stack");
2359 
2360   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2361 
2362   assert(!this->is_ext_suspended(),
2363          "a thread trying to self-suspend should not already be suspended");
2364 
2365   if (this->is_suspend_equivalent()) {
2366     // If we are self-suspending as a result of the lifting of a
2367     // suspend equivalent condition, then the suspend_equivalent
2368     // flag is not cleared until we set the ext_suspended flag so
2369     // that wait_for_ext_suspend_completion() returns consistent
2370     // results.
2371     this->clear_suspend_equivalent();
2372   }
2373 
2374   // A racing resume may have cancelled us before we grabbed SR_lock
2375   // above. Or another external suspend request could be waiting for us
2376   // by the time we return from SR_lock()->wait(). The thread
2377   // that requested the suspension may already be trying to walk our
2378   // stack and if we return now, we can change the stack out from under
2379   // it. This would be a "bad thing (TM)" and cause the stack walker
2380   // to crash. We stay self-suspended until there are no more pending
2381   // external suspend requests.
2382   while (is_external_suspend()) {
2383     ret++;
2384     this->set_ext_suspended();
2385 
2386     // _ext_suspended flag is cleared by java_resume()
2387     while (is_ext_suspended()) {
2388       this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2389     }
2390   }
2391 
2392   return ret;
2393 }
2394 
2395 #ifdef ASSERT
2396 // Verify the JavaThread has not yet been published in the Threads::list, and
2397 // hence doesn't need protection from concurrent access at this stage.
2398 void JavaThread::verify_not_published() {
2399   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2400   // since an unpublished JavaThread doesn't participate in the
2401   // Thread-SMR protocol for keeping a ThreadsList alive.
2402   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2403 }
2404 #endif
2405 
2406 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2407 // progress or when _suspend_flags is non-zero.
2408 // Current thread needs to self-suspend if there is a suspend request and/or
2409 // block if a safepoint is in progress.
2410 // Async exception ISN'T checked.
2411 // Note only the ThreadInVMfromNative transition can call this function
2412 // directly and when thread state is _thread_in_native_trans
2413 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2414   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2415 
2416   JavaThread *curJT = JavaThread::current();
2417   bool do_self_suspend = thread->is_external_suspend();
2418 
2419   assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2420 
2421   // If JNIEnv proxies are allowed, don't self-suspend if the target
2422   // thread is not the current thread. In older versions of jdbx, jdbx
2423   // threads could call into the VM with another thread's JNIEnv so we
2424   // can be here operating on behalf of a suspended thread (4432884).
2425   if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2426     JavaThreadState state = thread->thread_state();
2427 
2428     // We mark this thread_blocked state as a suspend-equivalent so
2429     // that a caller to is_ext_suspend_completed() won't be confused.
2430     // The suspend-equivalent state is cleared by java_suspend_self().
2431     thread->set_suspend_equivalent();
2432 
2433     // If the safepoint code sees the _thread_in_native_trans state, it will
2434     // wait until the thread changes to other thread state. There is no
2435     // guarantee on how soon we can obtain the SR_lock and complete the
2436     // self-suspend request. It would be a bad idea to let safepoint wait for
2437     // too long. Temporarily change the state to _thread_blocked to
2438     // let the VM thread know that this thread is ready for GC. The problem
2439     // of changing thread state is that safepoint could happen just after
2440     // java_suspend_self() returns after being resumed, and VM thread will
2441     // see the _thread_blocked state. We must check for safepoint
2442     // after restoring the state and make sure we won't leave while a safepoint
2443     // is in progress.
2444     thread->set_thread_state(_thread_blocked);
2445     thread->java_suspend_self();
2446     thread->set_thread_state(state);
2447 
2448     InterfaceSupport::serialize_thread_state_with_handler(thread);
2449   }
2450 
2451   SafepointMechanism::block_if_requested(curJT);
2452 
2453   if (thread->is_deopt_suspend()) {
2454     thread->clear_deopt_suspend();
2455     RegisterMap map(thread, false);
2456     frame f = thread->last_frame();
2457     while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2458       f = f.sender(&map);
2459     }
2460     if (f.id() == thread->must_deopt_id()) {
2461       thread->clear_must_deopt_id();
2462       f.deoptimize(thread);
2463     } else {
2464       fatal("missed deoptimization!");
2465     }
2466   }
2467 #if INCLUDE_TRACE
2468   if (thread->is_trace_suspend()) {
2469     TRACE_SUSPEND_THREAD(thread);
2470   }
2471 #endif
2472 }
2473 
2474 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2475 // progress or when _suspend_flags is non-zero.
2476 // Current thread needs to self-suspend if there is a suspend request and/or
2477 // block if a safepoint is in progress.
2478 // Also check for pending async exception (not including unsafe access error).
2479 // Note only the native==>VM/Java barriers can call this function and when
2480 // thread state is _thread_in_native_trans.
2481 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2482   check_safepoint_and_suspend_for_native_trans(thread);
2483 
2484   if (thread->has_async_exception()) {
2485     // We are in _thread_in_native_trans state, don't handle unsafe
2486     // access error since that may block.
2487     thread->check_and_handle_async_exceptions(false);
2488   }
2489 }
2490 
2491 // This is a variant of the normal
2492 // check_special_condition_for_native_trans with slightly different
2493 // semantics for use by critical native wrappers.  It does all the
2494 // normal checks but also performs the transition back into
2495 // thread_in_Java state.  This is required so that critical natives
2496 // can potentially block and perform a GC if they are the last thread
2497 // exiting the GCLocker.
2498 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2499   check_special_condition_for_native_trans(thread);
2500 
2501   // Finish the transition
2502   thread->set_thread_state(_thread_in_Java);
2503 
2504   if (thread->do_critical_native_unlock()) {
2505     ThreadInVMfromJavaNoAsyncException tiv(thread);
2506     GCLocker::unlock_critical(thread);
2507     thread->clear_critical_native_unlock();
2508   }
2509 }
2510 
2511 // We need to guarantee the Threads_lock here, since resumes are not
2512 // allowed during safepoint synchronization
2513 // Can only resume from an external suspension
2514 void JavaThread::java_resume() {
2515   assert_locked_or_safepoint(Threads_lock);
2516 
2517   // Sanity check: thread is gone, has started exiting or the thread
2518   // was not externally suspended.
2519   ThreadsListHandle tlh;
2520   if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2521     return;
2522   }
2523 
2524   MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2525 
2526   clear_external_suspend();
2527 
2528   if (is_ext_suspended()) {
2529     clear_ext_suspended();
2530     SR_lock()->notify_all();
2531   }
2532 }
2533 
2534 size_t JavaThread::_stack_red_zone_size = 0;
2535 size_t JavaThread::_stack_yellow_zone_size = 0;
2536 size_t JavaThread::_stack_reserved_zone_size = 0;
2537 size_t JavaThread::_stack_shadow_zone_size = 0;
2538 
2539 void JavaThread::create_stack_guard_pages() {
2540   if (!os::uses_stack_guard_pages() ||
2541       _stack_guard_state != stack_guard_unused ||
2542       (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2543       log_info(os, thread)("Stack guard page creation for thread "
2544                            UINTX_FORMAT " disabled", os::current_thread_id());
2545     return;
2546   }
2547   address low_addr = stack_end();
2548   size_t len = stack_guard_zone_size();
2549 
2550   assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2551   assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2552 
2553   int must_commit = os::must_commit_stack_guard_pages();
2554   // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2555 
2556   if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2557     log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2558     return;
2559   }
2560 
2561   if (os::guard_memory((char *) low_addr, len)) {
2562     _stack_guard_state = stack_guard_enabled;
2563   } else {
2564     log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2565       PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2566     if (os::uncommit_memory((char *) low_addr, len)) {
2567       log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2568     }
2569     return;
2570   }
2571 
2572   log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2573     PTR_FORMAT "-" PTR_FORMAT ".",
2574     os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2575 }
2576 
2577 void JavaThread::remove_stack_guard_pages() {
2578   assert(Thread::current() == this, "from different thread");
2579   if (_stack_guard_state == stack_guard_unused) return;
2580   address low_addr = stack_end();
2581   size_t len = stack_guard_zone_size();
2582 
2583   if (os::must_commit_stack_guard_pages()) {
2584     if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2585       _stack_guard_state = stack_guard_unused;
2586     } else {
2587       log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2588         PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2589       return;
2590     }
2591   } else {
2592     if (_stack_guard_state == stack_guard_unused) return;
2593     if (os::unguard_memory((char *) low_addr, len)) {
2594       _stack_guard_state = stack_guard_unused;
2595     } else {
2596       log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2597         PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2598       return;
2599     }
2600   }
2601 
2602   log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2603     PTR_FORMAT "-" PTR_FORMAT ".",
2604     os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2605 }
2606 
2607 void JavaThread::enable_stack_reserved_zone() {
2608   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2609   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2610 
2611   // The base notation is from the stack's point of view, growing downward.
2612   // We need to adjust it to work correctly with guard_memory()
2613   address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2614 
2615   guarantee(base < stack_base(),"Error calculating stack reserved zone");
2616   guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2617 
2618   if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2619     _stack_guard_state = stack_guard_enabled;
2620   } else {
2621     warning("Attempt to guard stack reserved zone failed.");
2622   }
2623   enable_register_stack_guard();
2624 }
2625 
2626 void JavaThread::disable_stack_reserved_zone() {
2627   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2628   assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2629 
2630   // Simply return if called for a thread that does not use guard pages.
2631   if (_stack_guard_state == stack_guard_unused) return;
2632 
2633   // The base notation is from the stack's point of view, growing downward.
2634   // We need to adjust it to work correctly with guard_memory()
2635   address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2636 
2637   if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2638     _stack_guard_state = stack_guard_reserved_disabled;
2639   } else {
2640     warning("Attempt to unguard stack reserved zone failed.");
2641   }
2642   disable_register_stack_guard();
2643 }
2644 
2645 void JavaThread::enable_stack_yellow_reserved_zone() {
2646   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2647   assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2648 
2649   // The base notation is from the stacks point of view, growing downward.
2650   // We need to adjust it to work correctly with guard_memory()
2651   address base = stack_red_zone_base();
2652 
2653   guarantee(base < stack_base(), "Error calculating stack yellow zone");
2654   guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2655 
2656   if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2657     _stack_guard_state = stack_guard_enabled;
2658   } else {
2659     warning("Attempt to guard stack yellow zone failed.");
2660   }
2661   enable_register_stack_guard();
2662 }
2663 
2664 void JavaThread::disable_stack_yellow_reserved_zone() {
2665   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2666   assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2667 
2668   // Simply return if called for a thread that does not use guard pages.
2669   if (_stack_guard_state == stack_guard_unused) return;
2670 
2671   // The base notation is from the stacks point of view, growing downward.
2672   // We need to adjust it to work correctly with guard_memory()
2673   address base = stack_red_zone_base();
2674 
2675   if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2676     _stack_guard_state = stack_guard_yellow_reserved_disabled;
2677   } else {
2678     warning("Attempt to unguard stack yellow zone failed.");
2679   }
2680   disable_register_stack_guard();
2681 }
2682 
2683 void JavaThread::enable_stack_red_zone() {
2684   // The base notation is from the stacks point of view, growing downward.
2685   // We need to adjust it to work correctly with guard_memory()
2686   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2687   address base = stack_red_zone_base() - stack_red_zone_size();
2688 
2689   guarantee(base < stack_base(), "Error calculating stack red zone");
2690   guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2691 
2692   if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2693     warning("Attempt to guard stack red zone failed.");
2694   }
2695 }
2696 
2697 void JavaThread::disable_stack_red_zone() {
2698   // The base notation is from the stacks point of view, growing downward.
2699   // We need to adjust it to work correctly with guard_memory()
2700   assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2701   address base = stack_red_zone_base() - stack_red_zone_size();
2702   if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2703     warning("Attempt to unguard stack red zone failed.");
2704   }
2705 }
2706 
2707 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2708   // ignore is there is no stack
2709   if (!has_last_Java_frame()) return;
2710   // traverse the stack frames. Starts from top frame.
2711   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2712     frame* fr = fst.current();
2713     f(fr, fst.register_map());
2714   }
2715 }
2716 
2717 
2718 #ifndef PRODUCT
2719 // Deoptimization
2720 // Function for testing deoptimization
2721 void JavaThread::deoptimize() {
2722   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2723   StackFrameStream fst(this, UseBiasedLocking);
2724   bool deopt = false;           // Dump stack only if a deopt actually happens.
2725   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2726   // Iterate over all frames in the thread and deoptimize
2727   for (; !fst.is_done(); fst.next()) {
2728     if (fst.current()->can_be_deoptimized()) {
2729 
2730       if (only_at) {
2731         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
2732         // consists of comma or carriage return separated numbers so
2733         // search for the current bci in that string.
2734         address pc = fst.current()->pc();
2735         nmethod* nm =  (nmethod*) fst.current()->cb();
2736         ScopeDesc* sd = nm->scope_desc_at(pc);
2737         char buffer[8];
2738         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2739         size_t len = strlen(buffer);
2740         const char * found = strstr(DeoptimizeOnlyAt, buffer);
2741         while (found != NULL) {
2742           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2743               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2744             // Check that the bci found is bracketed by terminators.
2745             break;
2746           }
2747           found = strstr(found + 1, buffer);
2748         }
2749         if (!found) {
2750           continue;
2751         }
2752       }
2753 
2754       if (DebugDeoptimization && !deopt) {
2755         deopt = true; // One-time only print before deopt
2756         tty->print_cr("[BEFORE Deoptimization]");
2757         trace_frames();
2758         trace_stack();
2759       }
2760       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2761     }
2762   }
2763 
2764   if (DebugDeoptimization && deopt) {
2765     tty->print_cr("[AFTER Deoptimization]");
2766     trace_frames();
2767   }
2768 }
2769 
2770 
2771 // Make zombies
2772 void JavaThread::make_zombies() {
2773   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2774     if (fst.current()->can_be_deoptimized()) {
2775       // it is a Java nmethod
2776       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2777       nm->make_not_entrant();
2778     }
2779   }
2780 }
2781 #endif // PRODUCT
2782 
2783 
2784 void JavaThread::deoptimized_wrt_marked_nmethods() {
2785   if (!has_last_Java_frame()) return;
2786   // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2787   StackFrameStream fst(this, UseBiasedLocking);
2788   for (; !fst.is_done(); fst.next()) {
2789     if (fst.current()->should_be_deoptimized()) {
2790       Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2791     }
2792   }
2793 }
2794 
2795 
2796 // If the caller is a NamedThread, then remember, in the current scope,
2797 // the given JavaThread in its _processed_thread field.
2798 class RememberProcessedThread: public StackObj {
2799   NamedThread* _cur_thr;
2800  public:
2801   RememberProcessedThread(JavaThread* jthr) {
2802     Thread* thread = Thread::current();
2803     if (thread->is_Named_thread()) {
2804       _cur_thr = (NamedThread *)thread;
2805       _cur_thr->set_processed_thread(jthr);
2806     } else {
2807       _cur_thr = NULL;
2808     }
2809   }
2810 
2811   ~RememberProcessedThread() {
2812     if (_cur_thr) {
2813       _cur_thr->set_processed_thread(NULL);
2814     }
2815   }
2816 };
2817 
2818 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2819   // Verify that the deferred card marks have been flushed.
2820   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2821 
2822   // Traverse the GCHandles
2823   Thread::oops_do(f, cf);
2824 
2825   JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2826 
2827   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2828          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2829 
2830   if (has_last_Java_frame()) {
2831     // Record JavaThread to GC thread
2832     RememberProcessedThread rpt(this);
2833 
2834     // Traverse the privileged stack
2835     if (_privileged_stack_top != NULL) {
2836       _privileged_stack_top->oops_do(f);
2837     }
2838 
2839     // traverse the registered growable array
2840     if (_array_for_gc != NULL) {
2841       for (int index = 0; index < _array_for_gc->length(); index++) {
2842         f->do_oop(_array_for_gc->adr_at(index));
2843       }
2844     }
2845 
2846     // Traverse the monitor chunks
2847     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2848       chunk->oops_do(f);
2849     }
2850 
2851     // Traverse the execution stack
2852     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2853       fst.current()->oops_do(f, cf, fst.register_map());
2854     }
2855   }
2856 
2857   // callee_target is never live across a gc point so NULL it here should
2858   // it still contain a methdOop.
2859 
2860   set_callee_target(NULL);
2861 
2862   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2863   // If we have deferred set_locals there might be oops waiting to be
2864   // written
2865   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2866   if (list != NULL) {
2867     for (int i = 0; i < list->length(); i++) {
2868       list->at(i)->oops_do(f);
2869     }
2870   }
2871 
2872   // Traverse instance variables at the end since the GC may be moving things
2873   // around using this function
2874   f->do_oop((oop*) &_threadObj);
2875   f->do_oop((oop*) &_vm_result);
2876   f->do_oop((oop*) &_exception_oop);
2877   f->do_oop((oop*) &_pending_async_exception);
2878 
2879   if (jvmti_thread_state() != NULL) {
2880     jvmti_thread_state()->oops_do(f);
2881   }
2882 }
2883 
2884 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2885   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2886          (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2887 
2888   if (has_last_Java_frame()) {
2889     // Traverse the execution stack
2890     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2891       fst.current()->nmethods_do(cf);
2892     }
2893   }
2894 }
2895 
2896 void JavaThread::metadata_do(void f(Metadata*)) {
2897   if (has_last_Java_frame()) {
2898     // Traverse the execution stack to call f() on the methods in the stack
2899     for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2900       fst.current()->metadata_do(f);
2901     }
2902   } else if (is_Compiler_thread()) {
2903     // need to walk ciMetadata in current compile tasks to keep alive.
2904     CompilerThread* ct = (CompilerThread*)this;
2905     if (ct->env() != NULL) {
2906       ct->env()->metadata_do(f);
2907     }
2908     CompileTask* task = ct->task();
2909     if (task != NULL) {
2910       task->metadata_do(f);
2911     }
2912   }
2913 }
2914 
2915 // Printing
2916 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2917   switch (_thread_state) {
2918   case _thread_uninitialized:     return "_thread_uninitialized";
2919   case _thread_new:               return "_thread_new";
2920   case _thread_new_trans:         return "_thread_new_trans";
2921   case _thread_in_native:         return "_thread_in_native";
2922   case _thread_in_native_trans:   return "_thread_in_native_trans";
2923   case _thread_in_vm:             return "_thread_in_vm";
2924   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
2925   case _thread_in_Java:           return "_thread_in_Java";
2926   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
2927   case _thread_blocked:           return "_thread_blocked";
2928   case _thread_blocked_trans:     return "_thread_blocked_trans";
2929   default:                        return "unknown thread state";
2930   }
2931 }
2932 
2933 #ifndef PRODUCT
2934 void JavaThread::print_thread_state_on(outputStream *st) const {
2935   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
2936 };
2937 void JavaThread::print_thread_state() const {
2938   print_thread_state_on(tty);
2939 }
2940 #endif // PRODUCT
2941 
2942 // Called by Threads::print() for VM_PrintThreads operation
2943 void JavaThread::print_on(outputStream *st) const {
2944   st->print_raw("\"");
2945   st->print_raw(get_thread_name());
2946   st->print_raw("\" ");
2947   oop thread_oop = threadObj();
2948   if (thread_oop != NULL) {
2949     st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2950     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
2951     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2952   }
2953   Thread::print_on(st);
2954   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2955   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2956   if (thread_oop != NULL) {
2957     st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2958   }
2959 #ifndef PRODUCT
2960   print_thread_state_on(st);
2961   _safepoint_state->print_on(st);
2962 #endif // PRODUCT
2963   if (is_Compiler_thread()) {
2964     CompileTask *task = ((CompilerThread*)this)->task();
2965     if (task != NULL) {
2966       st->print("   Compiling: ");
2967       task->print(st, NULL, true, false);
2968     } else {
2969       st->print("   No compile task");
2970     }
2971     st->cr();
2972   }
2973 }
2974 
2975 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2976   st->print("%s", get_thread_name_string(buf, buflen));
2977 }
2978 
2979 // Called by fatal error handler. The difference between this and
2980 // JavaThread::print() is that we can't grab lock or allocate memory.
2981 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2982   st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2983   oop thread_obj = threadObj();
2984   if (thread_obj != NULL) {
2985     if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2986   }
2987   st->print(" [");
2988   st->print("%s", _get_thread_state_name(_thread_state));
2989   if (osthread()) {
2990     st->print(", id=%d", osthread()->thread_id());
2991   }
2992   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2993             p2i(stack_end()), p2i(stack_base()));
2994   st->print("]");
2995 
2996   if (_threads_hazard_ptr != NULL) {
2997     st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
2998   }
2999   if (_nested_threads_hazard_ptr != NULL) {
3000     print_nested_threads_hazard_ptrs_on(st);
3001   }
3002   return;
3003 }
3004 
3005 // Verification
3006 
3007 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3008 
3009 void JavaThread::verify() {
3010   // Verify oops in the thread.
3011   oops_do(&VerifyOopClosure::verify_oop, NULL);
3012 
3013   // Verify the stack frames.
3014   frames_do(frame_verify);
3015 }
3016 
3017 // CR 6300358 (sub-CR 2137150)
3018 // Most callers of this method assume that it can't return NULL but a
3019 // thread may not have a name whilst it is in the process of attaching to
3020 // the VM - see CR 6412693, and there are places where a JavaThread can be
3021 // seen prior to having it's threadObj set (eg JNI attaching threads and
3022 // if vm exit occurs during initialization). These cases can all be accounted
3023 // for such that this method never returns NULL.
3024 const char* JavaThread::get_thread_name() const {
3025 #ifdef ASSERT
3026   // early safepoints can hit while current thread does not yet have TLS
3027   if (!SafepointSynchronize::is_at_safepoint()) {
3028     Thread *cur = Thread::current();
3029     if (!(cur->is_Java_thread() && cur == this)) {
3030       // Current JavaThreads are allowed to get their own name without
3031       // the Threads_lock.
3032       assert_locked_or_safepoint(Threads_lock);
3033     }
3034   }
3035 #endif // ASSERT
3036   return get_thread_name_string();
3037 }
3038 
3039 // Returns a non-NULL representation of this thread's name, or a suitable
3040 // descriptive string if there is no set name
3041 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3042   const char* name_str;
3043   oop thread_obj = threadObj();
3044   if (thread_obj != NULL) {
3045     oop name = java_lang_Thread::name(thread_obj);
3046     if (name != NULL) {
3047       if (buf == NULL) {
3048         name_str = java_lang_String::as_utf8_string(name);
3049       } else {
3050         name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3051       }
3052     } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3053       name_str = "<no-name - thread is attaching>";
3054     } else {
3055       name_str = Thread::name();
3056     }
3057   } else {
3058     name_str = Thread::name();
3059   }
3060   assert(name_str != NULL, "unexpected NULL thread name");
3061   return name_str;
3062 }
3063 
3064 
3065 const char* JavaThread::get_threadgroup_name() const {
3066   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3067   oop thread_obj = threadObj();
3068   if (thread_obj != NULL) {
3069     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3070     if (thread_group != NULL) {
3071       // ThreadGroup.name can be null
3072       return java_lang_ThreadGroup::name(thread_group);
3073     }
3074   }
3075   return NULL;
3076 }
3077 
3078 const char* JavaThread::get_parent_name() const {
3079   debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3080   oop thread_obj = threadObj();
3081   if (thread_obj != NULL) {
3082     oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3083     if (thread_group != NULL) {
3084       oop parent = java_lang_ThreadGroup::parent(thread_group);
3085       if (parent != NULL) {
3086         // ThreadGroup.name can be null
3087         return java_lang_ThreadGroup::name(parent);
3088       }
3089     }
3090   }
3091   return NULL;
3092 }
3093 
3094 ThreadPriority JavaThread::java_priority() const {
3095   oop thr_oop = threadObj();
3096   if (thr_oop == NULL) return NormPriority; // Bootstrapping
3097   ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3098   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3099   return priority;
3100 }
3101 
3102 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3103 
3104   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3105   // Link Java Thread object <-> C++ Thread
3106 
3107   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3108   // and put it into a new Handle.  The Handle "thread_oop" can then
3109   // be used to pass the C++ thread object to other methods.
3110 
3111   // Set the Java level thread object (jthread) field of the
3112   // new thread (a JavaThread *) to C++ thread object using the
3113   // "thread_oop" handle.
3114 
3115   // Set the thread field (a JavaThread *) of the
3116   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3117 
3118   Handle thread_oop(Thread::current(),
3119                     JNIHandles::resolve_non_null(jni_thread));
3120   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3121          "must be initialized");
3122   set_threadObj(thread_oop());
3123   java_lang_Thread::set_thread(thread_oop(), this);
3124 
3125   if (prio == NoPriority) {
3126     prio = java_lang_Thread::priority(thread_oop());
3127     assert(prio != NoPriority, "A valid priority should be present");
3128   }
3129 
3130   // Push the Java priority down to the native thread; needs Threads_lock
3131   Thread::set_priority(this, prio);
3132 
3133   // Add the new thread to the Threads list and set it in motion.
3134   // We must have threads lock in order to call Threads::add.
3135   // It is crucial that we do not block before the thread is
3136   // added to the Threads list for if a GC happens, then the java_thread oop
3137   // will not be visited by GC.
3138   Threads::add(this);
3139 }
3140 
3141 oop JavaThread::current_park_blocker() {
3142   // Support for JSR-166 locks
3143   oop thread_oop = threadObj();
3144   if (thread_oop != NULL &&
3145       JDK_Version::current().supports_thread_park_blocker()) {
3146     return java_lang_Thread::park_blocker(thread_oop);
3147   }
3148   return NULL;
3149 }
3150 
3151 
3152 void JavaThread::print_stack_on(outputStream* st) {
3153   if (!has_last_Java_frame()) return;
3154   ResourceMark rm;
3155   HandleMark   hm;
3156 
3157   RegisterMap reg_map(this);
3158   vframe* start_vf = last_java_vframe(&reg_map);
3159   int count = 0;
3160   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3161     if (f->is_java_frame()) {
3162       javaVFrame* jvf = javaVFrame::cast(f);
3163       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3164 
3165       // Print out lock information
3166       if (JavaMonitorsInStackTrace) {
3167         jvf->print_lock_info_on(st, count);
3168       }
3169     } else {
3170       // Ignore non-Java frames
3171     }
3172 
3173     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3174     count++;
3175     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3176   }
3177 }
3178 
3179 
3180 // JVMTI PopFrame support
3181 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3182   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3183   if (in_bytes(size_in_bytes) != 0) {
3184     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3185     _popframe_preserved_args_size = in_bytes(size_in_bytes);
3186     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3187   }
3188 }
3189 
3190 void* JavaThread::popframe_preserved_args() {
3191   return _popframe_preserved_args;
3192 }
3193 
3194 ByteSize JavaThread::popframe_preserved_args_size() {
3195   return in_ByteSize(_popframe_preserved_args_size);
3196 }
3197 
3198 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3199   int sz = in_bytes(popframe_preserved_args_size());
3200   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3201   return in_WordSize(sz / wordSize);
3202 }
3203 
3204 void JavaThread::popframe_free_preserved_args() {
3205   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3206   FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3207   _popframe_preserved_args = NULL;
3208   _popframe_preserved_args_size = 0;
3209 }
3210 
3211 #ifndef PRODUCT
3212 
3213 void JavaThread::trace_frames() {
3214   tty->print_cr("[Describe stack]");
3215   int frame_no = 1;
3216   for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3217     tty->print("  %d. ", frame_no++);
3218     fst.current()->print_value_on(tty, this);
3219     tty->cr();
3220   }
3221 }
3222 
3223 class PrintAndVerifyOopClosure: public OopClosure {
3224  protected:
3225   template <class T> inline void do_oop_work(T* p) {
3226     oop obj = RawAccess<>::oop_load(p);
3227     if (obj == NULL) return;
3228     tty->print(INTPTR_FORMAT ": ", p2i(p));
3229     if (oopDesc::is_oop_or_null(obj)) {
3230       if (obj->is_objArray()) {
3231         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3232       } else {
3233         obj->print();
3234       }
3235     } else {
3236       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3237     }
3238     tty->cr();
3239   }
3240  public:
3241   virtual void do_oop(oop* p) { do_oop_work(p); }
3242   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
3243 };
3244 
3245 
3246 static void oops_print(frame* f, const RegisterMap *map) {
3247   PrintAndVerifyOopClosure print;
3248   f->print_value();
3249   f->oops_do(&print, NULL, (RegisterMap*)map);
3250 }
3251 
3252 // Print our all the locations that contain oops and whether they are
3253 // valid or not.  This useful when trying to find the oldest frame
3254 // where an oop has gone bad since the frame walk is from youngest to
3255 // oldest.
3256 void JavaThread::trace_oops() {
3257   tty->print_cr("[Trace oops]");
3258   frames_do(oops_print);
3259 }
3260 
3261 
3262 #ifdef ASSERT
3263 // Print or validate the layout of stack frames
3264 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3265   ResourceMark rm;
3266   PRESERVE_EXCEPTION_MARK;
3267   FrameValues values;
3268   int frame_no = 0;
3269   for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3270     fst.current()->describe(values, ++frame_no);
3271     if (depth == frame_no) break;
3272   }
3273   if (validate_only) {
3274     values.validate();
3275   } else {
3276     tty->print_cr("[Describe stack layout]");
3277     values.print(this);
3278   }
3279 }
3280 #endif
3281 
3282 void JavaThread::trace_stack_from(vframe* start_vf) {
3283   ResourceMark rm;
3284   int vframe_no = 1;
3285   for (vframe* f = start_vf; f; f = f->sender()) {
3286     if (f->is_java_frame()) {
3287       javaVFrame::cast(f)->print_activation(vframe_no++);
3288     } else {
3289       f->print();
3290     }
3291     if (vframe_no > StackPrintLimit) {
3292       tty->print_cr("...<more frames>...");
3293       return;
3294     }
3295   }
3296 }
3297 
3298 
3299 void JavaThread::trace_stack() {
3300   if (!has_last_Java_frame()) return;
3301   ResourceMark rm;
3302   HandleMark   hm;
3303   RegisterMap reg_map(this);
3304   trace_stack_from(last_java_vframe(&reg_map));
3305 }
3306 
3307 
3308 #endif // PRODUCT
3309 
3310 
3311 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3312   assert(reg_map != NULL, "a map must be given");
3313   frame f = last_frame();
3314   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3315     if (vf->is_java_frame()) return javaVFrame::cast(vf);
3316   }
3317   return NULL;
3318 }
3319 
3320 
3321 Klass* JavaThread::security_get_caller_class(int depth) {
3322   vframeStream vfst(this);
3323   vfst.security_get_caller_frame(depth);
3324   if (!vfst.at_end()) {
3325     return vfst.method()->method_holder();
3326   }
3327   return NULL;
3328 }
3329 
3330 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3331   assert(thread->is_Compiler_thread(), "must be compiler thread");
3332   CompileBroker::compiler_thread_loop();
3333 }
3334 
3335 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3336   NMethodSweeper::sweeper_loop();
3337 }
3338 
3339 // Create a CompilerThread
3340 CompilerThread::CompilerThread(CompileQueue* queue,
3341                                CompilerCounters* counters)
3342                                : JavaThread(&compiler_thread_entry) {
3343   _env   = NULL;
3344   _log   = NULL;
3345   _task  = NULL;
3346   _queue = queue;
3347   _counters = counters;
3348   _buffer_blob = NULL;
3349   _compiler = NULL;
3350 
3351   // Compiler uses resource area for compilation, let's bias it to mtCompiler
3352   resource_area()->bias_to(mtCompiler);
3353 
3354 #ifndef PRODUCT
3355   _ideal_graph_printer = NULL;
3356 #endif
3357 }
3358 
3359 bool CompilerThread::can_call_java() const {
3360   return _compiler != NULL && _compiler->is_jvmci();
3361 }
3362 
3363 // Create sweeper thread
3364 CodeCacheSweeperThread::CodeCacheSweeperThread()
3365 : JavaThread(&sweeper_thread_entry) {
3366   _scanned_compiled_method = NULL;
3367 }
3368 
3369 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3370   JavaThread::oops_do(f, cf);
3371   if (_scanned_compiled_method != NULL && cf != NULL) {
3372     // Safepoints can occur when the sweeper is scanning an nmethod so
3373     // process it here to make sure it isn't unloaded in the middle of
3374     // a scan.
3375     cf->do_code_blob(_scanned_compiled_method);
3376   }
3377 }
3378 
3379 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3380   JavaThread::nmethods_do(cf);
3381   if (_scanned_compiled_method != NULL && cf != NULL) {
3382     // Safepoints can occur when the sweeper is scanning an nmethod so
3383     // process it here to make sure it isn't unloaded in the middle of
3384     // a scan.
3385     cf->do_code_blob(_scanned_compiled_method);
3386   }
3387 }
3388 
3389 
3390 // ======= Threads ========
3391 
3392 // The Threads class links together all active threads, and provides
3393 // operations over all threads. It is protected by the Threads_lock,
3394 // which is also used in other global contexts like safepointing.
3395 // ThreadsListHandles are used to safely perform operations on one
3396 // or more threads without the risk of the thread exiting during the
3397 // operation.
3398 //
3399 // Note: The Threads_lock is currently more widely used than we
3400 // would like. We are actively migrating Threads_lock uses to other
3401 // mechanisms in order to reduce Threads_lock contention.
3402 
3403 JavaThread* Threads::_thread_list = NULL;
3404 int         Threads::_number_of_threads = 0;
3405 int         Threads::_number_of_non_daemon_threads = 0;
3406 int         Threads::_return_code = 0;
3407 int         Threads::_thread_claim_parity = 0;
3408 size_t      JavaThread::_stack_size_at_create = 0;
3409 
3410 #ifdef ASSERT
3411 bool        Threads::_vm_complete = false;
3412 #endif
3413 
3414 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3415   Prefetch::read((void*)addr, prefetch_interval);
3416   return *addr;
3417 }
3418 
3419 // Possibly the ugliest for loop the world has seen. C++ does not allow
3420 // multiple types in the declaration section of the for loop. In this case
3421 // we are only dealing with pointers and hence can cast them. It looks ugly
3422 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3423 #define DO_JAVA_THREADS(LIST, X)                                                                                          \
3424     for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes,                           \
3425              *MACRO_list = (JavaThread*)(LIST),                                                                           \
3426              **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(),  \
3427              **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(),                                     \
3428              *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval);                 \
3429          MACRO_current_p != MACRO_end;                                                                                    \
3430          MACRO_current_p++,                                                                                               \
3431              X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3432 
3433 // All JavaThreads
3434 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3435 
3436 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3437 void Threads::threads_do(ThreadClosure* tc) {
3438   assert_locked_or_safepoint(Threads_lock);
3439   // ALL_JAVA_THREADS iterates through all JavaThreads
3440   ALL_JAVA_THREADS(p) {
3441     tc->do_thread(p);
3442   }
3443   // Someday we could have a table or list of all non-JavaThreads.
3444   // For now, just manually iterate through them.
3445   tc->do_thread(VMThread::vm_thread());
3446   Universe::heap()->gc_threads_do(tc);
3447   WatcherThread *wt = WatcherThread::watcher_thread();
3448   // Strictly speaking, the following NULL check isn't sufficient to make sure
3449   // the data for WatcherThread is still valid upon being examined. However,
3450   // considering that WatchThread terminates when the VM is on the way to
3451   // exit at safepoint, the chance of the above is extremely small. The right
3452   // way to prevent termination of WatcherThread would be to acquire
3453   // Terminator_lock, but we can't do that without violating the lock rank
3454   // checking in some cases.
3455   if (wt != NULL) {
3456     tc->do_thread(wt);
3457   }
3458 
3459   // If CompilerThreads ever become non-JavaThreads, add them here
3460 }
3461 
3462 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3463   int cp = Threads::thread_claim_parity();
3464   ALL_JAVA_THREADS(p) {
3465     if (p->claim_oops_do(is_par, cp)) {
3466       tc->do_thread(p);
3467     }
3468   }
3469   VMThread* vmt = VMThread::vm_thread();
3470   if (vmt->claim_oops_do(is_par, cp)) {
3471     tc->do_thread(vmt);
3472   }
3473 }
3474 
3475 // The system initialization in the library has three phases.
3476 //
3477 // Phase 1: java.lang.System class initialization
3478 //     java.lang.System is a primordial class loaded and initialized
3479 //     by the VM early during startup.  java.lang.System.<clinit>
3480 //     only does registerNatives and keeps the rest of the class
3481 //     initialization work later until thread initialization completes.
3482 //
3483 //     System.initPhase1 initializes the system properties, the static
3484 //     fields in, out, and err. Set up java signal handlers, OS-specific
3485 //     system settings, and thread group of the main thread.
3486 static void call_initPhase1(TRAPS) {
3487   Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3488   JavaValue result(T_VOID);
3489   JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3490                                          vmSymbols::void_method_signature(), CHECK);
3491 }
3492 
3493 // Phase 2. Module system initialization
3494 //     This will initialize the module system.  Only java.base classes
3495 //     can be loaded until phase 2 completes.
3496 //
3497 //     Call System.initPhase2 after the compiler initialization and jsr292
3498 //     classes get initialized because module initialization runs a lot of java
3499 //     code, that for performance reasons, should be compiled.  Also, this will
3500 //     enable the startup code to use lambda and other language features in this
3501 //     phase and onward.
3502 //
3503 //     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3504 static void call_initPhase2(TRAPS) {
3505   TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3506 
3507   Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3508 
3509   JavaValue result(T_INT);
3510   JavaCallArguments args;
3511   args.push_int(DisplayVMOutputToStderr);
3512   args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3513   JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3514                                          vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3515   if (result.get_jint() != JNI_OK) {
3516     vm_exit_during_initialization(); // no message or exception
3517   }
3518 
3519   universe_post_module_init();
3520 }
3521 
3522 // Phase 3. final setup - set security manager, system class loader and TCCL
3523 //
3524 //     This will instantiate and set the security manager, set the system class
3525 //     loader as well as the thread context class loader.  The security manager
3526 //     and system class loader may be a custom class loaded from -Xbootclasspath/a,
3527 //     other modules or the application's classpath.
3528 static void call_initPhase3(TRAPS) {
3529   Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3530   JavaValue result(T_VOID);
3531   JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3532                                          vmSymbols::void_method_signature(), CHECK);
3533 }
3534 
3535 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3536   TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3537 
3538   if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3539     create_vm_init_libraries();
3540   }
3541 
3542   initialize_class(vmSymbols::java_lang_String(), CHECK);
3543 
3544   // Inject CompactStrings value after the static initializers for String ran.
3545   java_lang_String::set_compact_strings(CompactStrings);
3546 
3547   // Initialize java_lang.System (needed before creating the thread)
3548   initialize_class(vmSymbols::java_lang_System(), CHECK);
3549   // The VM creates & returns objects of this class. Make sure it's initialized.
3550   initialize_class(vmSymbols::java_lang_Class(), CHECK);
3551   initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3552   Handle thread_group = create_initial_thread_group(CHECK);
3553   Universe::set_main_thread_group(thread_group());
3554   initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3555   oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3556   main_thread->set_threadObj(thread_object);
3557   // Set thread status to running since main thread has
3558   // been started and running.
3559   java_lang_Thread::set_thread_status(thread_object,
3560                                       java_lang_Thread::RUNNABLE);
3561 
3562   // The VM creates objects of this class.
3563   initialize_class(vmSymbols::java_lang_Module(), CHECK);
3564 
3565   // The VM preresolves methods to these classes. Make sure that they get initialized
3566   initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3567   initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3568 
3569   // Phase 1 of the system initialization in the library, java.lang.System class initialization
3570   call_initPhase1(CHECK);
3571 
3572   // get the Java runtime name after java.lang.System is initialized
3573   JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3574   JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3575 
3576   // an instance of OutOfMemory exception has been allocated earlier
3577   initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3578   initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3579   initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3580   initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3581   initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3582   initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3583   initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3584   initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3585 }
3586 
3587 void Threads::initialize_jsr292_core_classes(TRAPS) {
3588   TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3589 
3590   initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3591   initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3592   initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3593   initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3594 }
3595 
3596 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3597   extern void JDK_Version_init();
3598 
3599   // Preinitialize version info.
3600   VM_Version::early_initialize();
3601 
3602   // Check version
3603   if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3604 
3605   // Initialize library-based TLS
3606   ThreadLocalStorage::init();
3607 
3608   // Initialize the output stream module
3609   ostream_init();
3610 
3611   // Process java launcher properties.
3612   Arguments::process_sun_java_launcher_properties(args);
3613 
3614   // Initialize the os module
3615   os::init();
3616 
3617   // Record VM creation timing statistics
3618   TraceVmCreationTime create_vm_timer;
3619   create_vm_timer.start();
3620 
3621   // Initialize system properties.
3622   Arguments::init_system_properties();
3623 
3624   // So that JDK version can be used as a discriminator when parsing arguments
3625   JDK_Version_init();
3626 
3627   // Update/Initialize System properties after JDK version number is known
3628   Arguments::init_version_specific_system_properties();
3629 
3630   // Make sure to initialize log configuration *before* parsing arguments
3631   LogConfiguration::initialize(create_vm_timer.begin_time());
3632 
3633   // Parse arguments
3634   // Note: this internally calls os::init_container_support()
3635   jint parse_result = Arguments::parse(args);
3636   if (parse_result != JNI_OK) return parse_result;
3637 
3638   os::init_before_ergo();
3639 
3640   jint ergo_result = Arguments::apply_ergo();
3641   if (ergo_result != JNI_OK) return ergo_result;
3642 
3643   // Final check of all ranges after ergonomics which may change values.
3644   if (!CommandLineFlagRangeList::check_ranges()) {
3645     return JNI_EINVAL;
3646   }
3647 
3648   // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3649   bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3650   if (!constraint_result) {
3651     return JNI_EINVAL;
3652   }
3653 
3654   CommandLineFlagWriteableList::mark_startup();
3655 
3656   if (PauseAtStartup) {
3657     os::pause();
3658   }
3659 
3660   HOTSPOT_VM_INIT_BEGIN();
3661 
3662   // Timing (must come after argument parsing)
3663   TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3664 
3665 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3666   // Initialize assert poison page mechanism.
3667   if (ShowRegistersOnAssert) {
3668     initialize_assert_poison();
3669   }
3670 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3671 
3672   // Initialize the os module after parsing the args
3673   jint os_init_2_result = os::init_2();
3674   if (os_init_2_result != JNI_OK) return os_init_2_result;
3675 
3676   SafepointMechanism::initialize();
3677 
3678   jint adjust_after_os_result = Arguments::adjust_after_os();
3679   if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3680 
3681   // Initialize output stream logging
3682   ostream_init_log();
3683 
3684   // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3685   // Must be before create_vm_init_agents()
3686   if (Arguments::init_libraries_at_startup()) {
3687     convert_vm_init_libraries_to_agents();
3688   }
3689 
3690   // Launch -agentlib/-agentpath and converted -Xrun agents
3691   if (Arguments::init_agents_at_startup()) {
3692     create_vm_init_agents();
3693   }
3694 
3695   // Initialize Threads state
3696   _thread_list = NULL;
3697   _number_of_threads = 0;
3698   _number_of_non_daemon_threads = 0;
3699 
3700   // Initialize global data structures and create system classes in heap
3701   vm_init_globals();
3702 
3703 #if INCLUDE_JVMCI
3704   if (JVMCICounterSize > 0) {
3705     JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3706     memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3707   } else {
3708     JavaThread::_jvmci_old_thread_counters = NULL;
3709   }
3710 #endif // INCLUDE_JVMCI
3711 
3712   // Attach the main thread to this os thread
3713   JavaThread* main_thread = new JavaThread();
3714   main_thread->set_thread_state(_thread_in_vm);
3715   main_thread->initialize_thread_current();
3716   // must do this before set_active_handles
3717   main_thread->record_stack_base_and_size();
3718   main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3719 
3720   if (!main_thread->set_as_starting_thread()) {
3721     vm_shutdown_during_initialization(
3722                                       "Failed necessary internal allocation. Out of swap space");
3723     main_thread->smr_delete();
3724     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3725     return JNI_ENOMEM;
3726   }
3727 
3728   // Enable guard page *after* os::create_main_thread(), otherwise it would
3729   // crash Linux VM, see notes in os_linux.cpp.
3730   main_thread->create_stack_guard_pages();
3731 
3732   // Initialize Java-Level synchronization subsystem
3733   ObjectMonitor::Initialize();
3734 
3735   // Initialize global modules
3736   jint status = init_globals();
3737   if (status != JNI_OK) {
3738     main_thread->smr_delete();
3739     *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3740     return status;
3741   }
3742 
3743   if (TRACE_INITIALIZE() != JNI_OK) {
3744     vm_exit_during_initialization("Failed to initialize tracing backend");
3745   }
3746 
3747   // Should be done after the heap is fully created
3748   main_thread->cache_global_variables();
3749 
3750   HandleMark hm;
3751 
3752   { MutexLocker mu(Threads_lock);
3753     Threads::add(main_thread);
3754   }
3755 
3756   // Any JVMTI raw monitors entered in onload will transition into
3757   // real raw monitor. VM is setup enough here for raw monitor enter.
3758   JvmtiExport::transition_pending_onload_raw_monitors();
3759 
3760   // Create the VMThread
3761   { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3762 
3763   VMThread::create();
3764     Thread* vmthread = VMThread::vm_thread();
3765 
3766     if (!os::create_thread(vmthread, os::vm_thread)) {
3767       vm_exit_during_initialization("Cannot create VM thread. "
3768                                     "Out of system resources.");
3769     }
3770 
3771     // Wait for the VM thread to become ready, and VMThread::run to initialize
3772     // Monitors can have spurious returns, must always check another state flag
3773     {
3774       MutexLocker ml(Notify_lock);
3775       os::start_thread(vmthread);
3776       while (vmthread->active_handles() == NULL) {
3777         Notify_lock->wait();
3778       }
3779     }
3780   }
3781 
3782   assert(Universe::is_fully_initialized(), "not initialized");
3783   if (VerifyDuringStartup) {
3784     // Make sure we're starting with a clean slate.
3785     VM_Verify verify_op;
3786     VMThread::execute(&verify_op);
3787   }
3788 
3789   Thread* THREAD = Thread::current();
3790 
3791   // Always call even when there are not JVMTI environments yet, since environments
3792   // may be attached late and JVMTI must track phases of VM execution
3793   JvmtiExport::enter_early_start_phase();
3794 
3795   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3796   JvmtiExport::post_early_vm_start();
3797 
3798   initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3799 
3800   // We need this for ClassDataSharing - the initial vm.info property is set
3801   // with the default value of CDS "sharing" which may be reset through
3802   // command line options.
3803   reset_vm_info_property(CHECK_JNI_ERR);
3804 
3805   quicken_jni_functions();
3806 
3807   // No more stub generation allowed after that point.
3808   StubCodeDesc::freeze();
3809 
3810   // Set flag that basic initialization has completed. Used by exceptions and various
3811   // debug stuff, that does not work until all basic classes have been initialized.
3812   set_init_completed();
3813 
3814   LogConfiguration::post_initialize();
3815   Metaspace::post_initialize();
3816 
3817   HOTSPOT_VM_INIT_END();
3818 
3819   // record VM initialization completion time
3820 #if INCLUDE_MANAGEMENT
3821   Management::record_vm_init_completed();
3822 #endif // INCLUDE_MANAGEMENT
3823 
3824   // Signal Dispatcher needs to be started before VMInit event is posted
3825   os::signal_init(CHECK_JNI_ERR);
3826 
3827   // Start Attach Listener if +StartAttachListener or it can't be started lazily
3828   if (!DisableAttachMechanism) {
3829     AttachListener::vm_start();
3830     if (StartAttachListener || AttachListener::init_at_startup()) {
3831       AttachListener::init();
3832     }
3833   }
3834 
3835   // Launch -Xrun agents
3836   // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3837   // back-end can launch with -Xdebug -Xrunjdwp.
3838   if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3839     create_vm_init_libraries();
3840   }
3841 
3842   if (CleanChunkPoolAsync) {
3843     Chunk::start_chunk_pool_cleaner_task();
3844   }
3845 
3846   // initialize compiler(s)
3847 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3848 #if INCLUDE_JVMCI
3849   bool force_JVMCI_intialization = false;
3850   if (EnableJVMCI) {
3851     // Initialize JVMCI eagerly when it is explicitly requested.
3852     // Or when JVMCIPrintProperties is enabled.
3853     // The JVMCI Java initialization code will read this flag and
3854     // do the printing if it's set.
3855     force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3856 
3857     if (!force_JVMCI_intialization) {
3858       // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3859       // compilations via JVMCI will not actually block until JVMCI is initialized.
3860       force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3861     }
3862   }
3863 #endif
3864   CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3865   // Postpone completion of compiler initialization to after JVMCI
3866   // is initialized to avoid timeouts of blocking compilations.
3867   if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3868     CompileBroker::compilation_init_phase2();
3869   }
3870 #endif
3871 
3872   // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3873   // It is done after compilers are initialized, because otherwise compilations of
3874   // signature polymorphic MH intrinsics can be missed
3875   // (see SystemDictionary::find_method_handle_intrinsic).
3876   initialize_jsr292_core_classes(CHECK_JNI_ERR);
3877 
3878   // This will initialize the module system.  Only java.base classes can be
3879   // loaded until phase 2 completes
3880   call_initPhase2(CHECK_JNI_ERR);
3881 
3882   // Always call even when there are not JVMTI environments yet, since environments
3883   // may be attached late and JVMTI must track phases of VM execution
3884   JvmtiExport::enter_start_phase();
3885 
3886   // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3887   JvmtiExport::post_vm_start();
3888 
3889   // Final system initialization including security manager and system class loader
3890   call_initPhase3(CHECK_JNI_ERR);
3891 
3892   // cache the system and platform class loaders
3893   SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3894 
3895 #if INCLUDE_CDS
3896   if (DumpSharedSpaces) {
3897     // capture the module path info from the ModuleEntryTable
3898     ClassLoader::initialize_module_path(THREAD);
3899   }
3900 #endif
3901 
3902 #if INCLUDE_JVMCI
3903   if (force_JVMCI_intialization) {
3904     JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3905     CompileBroker::compilation_init_phase2();
3906   }
3907 #endif
3908 
3909   // Always call even when there are not JVMTI environments yet, since environments
3910   // may be attached late and JVMTI must track phases of VM execution
3911   JvmtiExport::enter_live_phase();
3912 
3913   // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3914   JvmtiExport::post_vm_initialized();
3915 
3916   if (TRACE_START() != JNI_OK) {
3917     vm_exit_during_initialization("Failed to start tracing backend.");
3918   }
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 #if INCLUDE_ALL_GCS
4482 // Used by ParallelScavenge
4483 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4484   ALL_JAVA_THREADS(p) {
4485     q->enqueue(new ThreadRootsTask(p));
4486   }
4487   q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4488 }
4489 
4490 // Used by Parallel Old
4491 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4492   ALL_JAVA_THREADS(p) {
4493     q->enqueue(new ThreadRootsMarkingTask(p));
4494   }
4495   q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4496 }
4497 #endif // INCLUDE_ALL_GCS
4498 
4499 void Threads::nmethods_do(CodeBlobClosure* cf) {
4500   ALL_JAVA_THREADS(p) {
4501     // This is used by the code cache sweeper to mark nmethods that are active
4502     // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4503     // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4504     if(!p->is_Code_cache_sweeper_thread()) {
4505       p->nmethods_do(cf);
4506     }
4507   }
4508 }
4509 
4510 void Threads::metadata_do(void f(Metadata*)) {
4511   ALL_JAVA_THREADS(p) {
4512     p->metadata_do(f);
4513   }
4514 }
4515 
4516 class ThreadHandlesClosure : public ThreadClosure {
4517   void (*_f)(Metadata*);
4518  public:
4519   ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4520   virtual void do_thread(Thread* thread) {
4521     thread->metadata_handles_do(_f);
4522   }
4523 };
4524 
4525 void Threads::metadata_handles_do(void f(Metadata*)) {
4526   // Only walk the Handles in Thread.
4527   ThreadHandlesClosure handles_closure(f);
4528   threads_do(&handles_closure);
4529 }
4530 
4531 void Threads::deoptimized_wrt_marked_nmethods() {
4532   ALL_JAVA_THREADS(p) {
4533     p->deoptimized_wrt_marked_nmethods();
4534   }
4535 }
4536 
4537 
4538 // Get count Java threads that are waiting to enter the specified monitor.
4539 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4540                                                          int count,
4541                                                          address monitor) {
4542   GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4543 
4544   int i = 0;
4545   DO_JAVA_THREADS(t_list, p) {
4546     if (!p->can_call_java()) continue;
4547 
4548     address pending = (address)p->current_pending_monitor();
4549     if (pending == monitor) {             // found a match
4550       if (i < count) result->append(p);   // save the first count matches
4551       i++;
4552     }
4553   }
4554 
4555   return result;
4556 }
4557 
4558 
4559 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4560                                                       address owner) {
4561   // NULL owner means not locked so we can skip the search
4562   if (owner == NULL) return NULL;
4563 
4564   DO_JAVA_THREADS(t_list, p) {
4565     // first, see if owner is the address of a Java thread
4566     if (owner == (address)p) return p;
4567   }
4568 
4569   // Cannot assert on lack of success here since this function may be
4570   // used by code that is trying to report useful problem information
4571   // like deadlock detection.
4572   if (UseHeavyMonitors) return NULL;
4573 
4574   // If we didn't find a matching Java thread and we didn't force use of
4575   // heavyweight monitors, then the owner is the stack address of the
4576   // Lock Word in the owning Java thread's stack.
4577   //
4578   JavaThread* the_owner = NULL;
4579   DO_JAVA_THREADS(t_list, q) {
4580     if (q->is_lock_owned(owner)) {
4581       the_owner = q;
4582       break;
4583     }
4584   }
4585 
4586   // cannot assert on lack of success here; see above comment
4587   return the_owner;
4588 }
4589 
4590 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4591 void Threads::print_on(outputStream* st, bool print_stacks,
4592                        bool internal_format, bool print_concurrent_locks) {
4593   char buf[32];
4594   st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4595 
4596   st->print_cr("Full thread dump %s (%s %s):",
4597                Abstract_VM_Version::vm_name(),
4598                Abstract_VM_Version::vm_release(),
4599                Abstract_VM_Version::vm_info_string());
4600   st->cr();
4601 
4602 #if INCLUDE_SERVICES
4603   // Dump concurrent locks
4604   ConcurrentLocksDump concurrent_locks;
4605   if (print_concurrent_locks) {
4606     concurrent_locks.dump_at_safepoint();
4607   }
4608 #endif // INCLUDE_SERVICES
4609 
4610   ThreadsSMRSupport::print_info_on(st);
4611   st->cr();
4612 
4613   ALL_JAVA_THREADS(p) {
4614     ResourceMark rm;
4615     p->print_on(st);
4616     if (print_stacks) {
4617       if (internal_format) {
4618         p->trace_stack();
4619       } else {
4620         p->print_stack_on(st);
4621       }
4622     }
4623     st->cr();
4624 #if INCLUDE_SERVICES
4625     if (print_concurrent_locks) {
4626       concurrent_locks.print_locks_on(p, st);
4627     }
4628 #endif // INCLUDE_SERVICES
4629   }
4630 
4631   VMThread::vm_thread()->print_on(st);
4632   st->cr();
4633   Universe::heap()->print_gc_threads_on(st);
4634   WatcherThread* wt = WatcherThread::watcher_thread();
4635   if (wt != NULL) {
4636     wt->print_on(st);
4637     st->cr();
4638   }
4639 
4640   st->flush();
4641 }
4642 
4643 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4644                              int buflen, bool* found_current) {
4645   if (this_thread != NULL) {
4646     bool is_current = (current == this_thread);
4647     *found_current = *found_current || is_current;
4648     st->print("%s", is_current ? "=>" : "  ");
4649 
4650     st->print(PTR_FORMAT, p2i(this_thread));
4651     st->print(" ");
4652     this_thread->print_on_error(st, buf, buflen);
4653     st->cr();
4654   }
4655 }
4656 
4657 class PrintOnErrorClosure : public ThreadClosure {
4658   outputStream* _st;
4659   Thread* _current;
4660   char* _buf;
4661   int _buflen;
4662   bool* _found_current;
4663  public:
4664   PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4665                       int buflen, bool* found_current) :
4666    _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4667 
4668   virtual void do_thread(Thread* thread) {
4669     Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4670   }
4671 };
4672 
4673 // Threads::print_on_error() is called by fatal error handler. It's possible
4674 // that VM is not at safepoint and/or current thread is inside signal handler.
4675 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4676 // memory (even in resource area), it might deadlock the error handler.
4677 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4678                              int buflen) {
4679   ThreadsSMRSupport::print_info_on(st);
4680   st->cr();
4681 
4682   bool found_current = false;
4683   st->print_cr("Java Threads: ( => current thread )");
4684   ALL_JAVA_THREADS(thread) {
4685     print_on_error(thread, st, current, buf, buflen, &found_current);
4686   }
4687   st->cr();
4688 
4689   st->print_cr("Other Threads:");
4690   print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4691   print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4692 
4693   PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4694   Universe::heap()->gc_threads_do(&print_closure);
4695 
4696   if (!found_current) {
4697     st->cr();
4698     st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4699     current->print_on_error(st, buf, buflen);
4700     st->cr();
4701   }
4702   st->cr();
4703 
4704   st->print_cr("Threads with active compile tasks:");
4705   print_threads_compiling(st, buf, buflen);
4706 }
4707 
4708 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4709   ALL_JAVA_THREADS(thread) {
4710     if (thread->is_Compiler_thread()) {
4711       CompilerThread* ct = (CompilerThread*) thread;
4712 
4713       // Keep task in local variable for NULL check.
4714       // ct->_task might be set to NULL by concurring compiler thread
4715       // because it completed the compilation. The task is never freed,
4716       // though, just returned to a free list.
4717       CompileTask* task = ct->task();
4718       if (task != NULL) {
4719         thread->print_name_on_error(st, buf, buflen);
4720         task->print(st, NULL, true, true);
4721       }
4722     }
4723   }
4724 }
4725 
4726 
4727 // Internal SpinLock and Mutex
4728 // Based on ParkEvent
4729 
4730 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4731 //
4732 // We employ SpinLocks _only for low-contention, fixed-length
4733 // short-duration critical sections where we're concerned
4734 // about native mutex_t or HotSpot Mutex:: latency.
4735 // The mux construct provides a spin-then-block mutual exclusion
4736 // mechanism.
4737 //
4738 // Testing has shown that contention on the ListLock guarding gFreeList
4739 // is common.  If we implement ListLock as a simple SpinLock it's common
4740 // for the JVM to devolve to yielding with little progress.  This is true
4741 // despite the fact that the critical sections protected by ListLock are
4742 // extremely short.
4743 //
4744 // TODO-FIXME: ListLock should be of type SpinLock.
4745 // We should make this a 1st-class type, integrated into the lock
4746 // hierarchy as leaf-locks.  Critically, the SpinLock structure
4747 // should have sufficient padding to avoid false-sharing and excessive
4748 // cache-coherency traffic.
4749 
4750 
4751 typedef volatile int SpinLockT;
4752 
4753 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4754   if (Atomic::cmpxchg (1, adr, 0) == 0) {
4755     return;   // normal fast-path return
4756   }
4757 
4758   // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4759   TEVENT(SpinAcquire - ctx);
4760   int ctr = 0;
4761   int Yields = 0;
4762   for (;;) {
4763     while (*adr != 0) {
4764       ++ctr;
4765       if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4766         if (Yields > 5) {
4767           os::naked_short_sleep(1);
4768         } else {
4769           os::naked_yield();
4770           ++Yields;
4771         }
4772       } else {
4773         SpinPause();
4774       }
4775     }
4776     if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4777   }
4778 }
4779 
4780 void Thread::SpinRelease(volatile int * adr) {
4781   assert(*adr != 0, "invariant");
4782   OrderAccess::fence();      // guarantee at least release consistency.
4783   // Roach-motel semantics.
4784   // It's safe if subsequent LDs and STs float "up" into the critical section,
4785   // but prior LDs and STs within the critical section can't be allowed
4786   // to reorder or float past the ST that releases the lock.
4787   // Loads and stores in the critical section - which appear in program
4788   // order before the store that releases the lock - must also appear
4789   // before the store that releases the lock in memory visibility order.
4790   // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4791   // the ST of 0 into the lock-word which releases the lock, so fence
4792   // more than covers this on all platforms.
4793   *adr = 0;
4794 }
4795 
4796 // muxAcquire and muxRelease:
4797 //
4798 // *  muxAcquire and muxRelease support a single-word lock-word construct.
4799 //    The LSB of the word is set IFF the lock is held.
4800 //    The remainder of the word points to the head of a singly-linked list
4801 //    of threads blocked on the lock.
4802 //
4803 // *  The current implementation of muxAcquire-muxRelease uses its own
4804 //    dedicated Thread._MuxEvent instance.  If we're interested in
4805 //    minimizing the peak number of extant ParkEvent instances then
4806 //    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4807 //    as certain invariants were satisfied.  Specifically, care would need
4808 //    to be taken with regards to consuming unpark() "permits".
4809 //    A safe rule of thumb is that a thread would never call muxAcquire()
4810 //    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4811 //    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
4812 //    consume an unpark() permit intended for monitorenter, for instance.
4813 //    One way around this would be to widen the restricted-range semaphore
4814 //    implemented in park().  Another alternative would be to provide
4815 //    multiple instances of the PlatformEvent() for each thread.  One
4816 //    instance would be dedicated to muxAcquire-muxRelease, for instance.
4817 //
4818 // *  Usage:
4819 //    -- Only as leaf locks
4820 //    -- for short-term locking only as muxAcquire does not perform
4821 //       thread state transitions.
4822 //
4823 // Alternatives:
4824 // *  We could implement muxAcquire and muxRelease with MCS or CLH locks
4825 //    but with parking or spin-then-park instead of pure spinning.
4826 // *  Use Taura-Oyama-Yonenzawa locks.
4827 // *  It's possible to construct a 1-0 lock if we encode the lockword as
4828 //    (List,LockByte).  Acquire will CAS the full lockword while Release
4829 //    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
4830 //    acquiring threads use timers (ParkTimed) to detect and recover from
4831 //    the stranding window.  Thread/Node structures must be aligned on 256-byte
4832 //    boundaries by using placement-new.
4833 // *  Augment MCS with advisory back-link fields maintained with CAS().
4834 //    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4835 //    The validity of the backlinks must be ratified before we trust the value.
4836 //    If the backlinks are invalid the exiting thread must back-track through the
4837 //    the forward links, which are always trustworthy.
4838 // *  Add a successor indication.  The LockWord is currently encoded as
4839 //    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
4840 //    to provide the usual futile-wakeup optimization.
4841 //    See RTStt for details.
4842 // *  Consider schedctl.sc_nopreempt to cover the critical section.
4843 //
4844 
4845 
4846 const intptr_t LOCKBIT = 1;
4847 
4848 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4849   intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4850   if (w == 0) return;
4851   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4852     return;
4853   }
4854 
4855   TEVENT(muxAcquire - Contention);
4856   ParkEvent * const Self = Thread::current()->_MuxEvent;
4857   assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4858   for (;;) {
4859     int its = (os::is_MP() ? 100 : 0) + 1;
4860 
4861     // Optional spin phase: spin-then-park strategy
4862     while (--its >= 0) {
4863       w = *Lock;
4864       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4865         return;
4866       }
4867     }
4868 
4869     Self->reset();
4870     Self->OnList = intptr_t(Lock);
4871     // The following fence() isn't _strictly necessary as the subsequent
4872     // CAS() both serializes execution and ratifies the fetched *Lock value.
4873     OrderAccess::fence();
4874     for (;;) {
4875       w = *Lock;
4876       if ((w & LOCKBIT) == 0) {
4877         if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4878           Self->OnList = 0;   // hygiene - allows stronger asserts
4879           return;
4880         }
4881         continue;      // Interference -- *Lock changed -- Just retry
4882       }
4883       assert(w & LOCKBIT, "invariant");
4884       Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4885       if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4886     }
4887 
4888     while (Self->OnList != 0) {
4889       Self->park();
4890     }
4891   }
4892 }
4893 
4894 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4895   intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4896   if (w == 0) return;
4897   if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4898     return;
4899   }
4900 
4901   TEVENT(muxAcquire - Contention);
4902   ParkEvent * ReleaseAfter = NULL;
4903   if (ev == NULL) {
4904     ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4905   }
4906   assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4907   for (;;) {
4908     guarantee(ev->OnList == 0, "invariant");
4909     int its = (os::is_MP() ? 100 : 0) + 1;
4910 
4911     // Optional spin phase: spin-then-park strategy
4912     while (--its >= 0) {
4913       w = *Lock;
4914       if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4915         if (ReleaseAfter != NULL) {
4916           ParkEvent::Release(ReleaseAfter);
4917         }
4918         return;
4919       }
4920     }
4921 
4922     ev->reset();
4923     ev->OnList = intptr_t(Lock);
4924     // The following fence() isn't _strictly necessary as the subsequent
4925     // CAS() both serializes execution and ratifies the fetched *Lock value.
4926     OrderAccess::fence();
4927     for (;;) {
4928       w = *Lock;
4929       if ((w & LOCKBIT) == 0) {
4930         if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4931           ev->OnList = 0;
4932           // We call ::Release while holding the outer lock, thus
4933           // artificially lengthening the critical section.
4934           // Consider deferring the ::Release() until the subsequent unlock(),
4935           // after we've dropped the outer lock.
4936           if (ReleaseAfter != NULL) {
4937             ParkEvent::Release(ReleaseAfter);
4938           }
4939           return;
4940         }
4941         continue;      // Interference -- *Lock changed -- Just retry
4942       }
4943       assert(w & LOCKBIT, "invariant");
4944       ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4945       if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4946     }
4947 
4948     while (ev->OnList != 0) {
4949       ev->park();
4950     }
4951   }
4952 }
4953 
4954 // Release() must extract a successor from the list and then wake that thread.
4955 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4956 // similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
4957 // Release() would :
4958 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4959 // (B) Extract a successor from the private list "in-hand"
4960 // (C) attempt to CAS() the residual back into *Lock over null.
4961 //     If there were any newly arrived threads and the CAS() would fail.
4962 //     In that case Release() would detach the RATs, re-merge the list in-hand
4963 //     with the RATs and repeat as needed.  Alternately, Release() might
4964 //     detach and extract a successor, but then pass the residual list to the wakee.
4965 //     The wakee would be responsible for reattaching and remerging before it
4966 //     competed for the lock.
4967 //
4968 // Both "pop" and DMR are immune from ABA corruption -- there can be
4969 // multiple concurrent pushers, but only one popper or detacher.
4970 // This implementation pops from the head of the list.  This is unfair,
4971 // but tends to provide excellent throughput as hot threads remain hot.
4972 // (We wake recently run threads first).
4973 //
4974 // All paths through muxRelease() will execute a CAS.
4975 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4976 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4977 // executed within the critical section are complete and globally visible before the
4978 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4979 void Thread::muxRelease(volatile intptr_t * Lock)  {
4980   for (;;) {
4981     const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4982     assert(w & LOCKBIT, "invariant");
4983     if (w == LOCKBIT) return;
4984     ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4985     assert(List != NULL, "invariant");
4986     assert(List->OnList == intptr_t(Lock), "invariant");
4987     ParkEvent * const nxt = List->ListNext;
4988     guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4989 
4990     // The following CAS() releases the lock and pops the head element.
4991     // The CAS() also ratifies the previously fetched lock-word value.
4992     if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4993       continue;
4994     }
4995     List->OnList = 0;
4996     OrderAccess::fence();
4997     List->unpark();
4998     return;
4999   }
5000 }
5001 
5002 
5003 void Threads::verify() {
5004   ALL_JAVA_THREADS(p) {
5005     p->verify();
5006   }
5007   VMThread* thread = VMThread::vm_thread();
5008   if (thread != NULL) thread->verify();
5009 }