1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "cds/dynamicArchive.hpp"
  28 #include "ci/ciEnv.hpp"
  29 #include "classfile/javaClasses.inline.hpp"
  30 #include "classfile/javaThreadStatus.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "classfile/vmClasses.hpp"
  33 #include "classfile/vmSymbols.hpp"
  34 #include "code/codeCache.hpp"
  35 #include "code/scopeDesc.hpp"
  36 #include "compiler/compileTask.hpp"
  37 #include "compiler/compilerThread.hpp"
  38 #include "gc/shared/oopStorage.hpp"
  39 #include "gc/shared/oopStorageSet.hpp"
  40 #include "gc/shared/tlab_globals.hpp"
  41 #include "jfr/jfrEvents.hpp"
  42 #include "jvm.h"
  43 #include "jvmtifiles/jvmtiEnv.hpp"
  44 #include "logging/log.hpp"
  45 #include "logging/logAsyncWriter.hpp"
  46 #include "logging/logStream.hpp"
  47 #include "memory/allocation.inline.hpp"
  48 #include "memory/iterator.hpp"
  49 #include "memory/universe.hpp"
  50 #include "oops/access.inline.hpp"
  51 #include "oops/instanceKlass.hpp"
  52 #include "oops/klass.inline.hpp"
  53 #include "oops/oop.inline.hpp"
  54 #include "oops/oopHandle.inline.hpp"
  55 #include "oops/verifyOopClosure.hpp"
  56 #include "prims/jvm_misc.hpp"
  57 #include "prims/jvmtiDeferredUpdates.hpp"
  58 #include "prims/jvmtiExport.hpp"
  59 #include "prims/jvmtiThreadState.inline.hpp"
  60 #include "runtime/atomic.hpp"
  61 #include "runtime/continuation.hpp"
  62 #include "runtime/continuationEntry.inline.hpp"
  63 #include "runtime/continuationHelper.inline.hpp"
  64 #include "runtime/deoptimization.hpp"
  65 #include "runtime/frame.inline.hpp"
  66 #include "runtime/handles.inline.hpp"
  67 #include "runtime/handshake.hpp"
  68 #include "runtime/interfaceSupport.inline.hpp"
  69 #include "runtime/java.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/javaThread.inline.hpp"
  72 #include "runtime/jniHandles.inline.hpp"
  73 #include "runtime/mutexLocker.hpp"
  74 #include "runtime/orderAccess.hpp"
  75 #include "runtime/osThread.hpp"
  76 #include "runtime/safepoint.hpp"
  77 #include "runtime/safepointMechanism.inline.hpp"
  78 #include "runtime/safepointVerifiers.hpp"
  79 #include "runtime/serviceThread.hpp"
  80 #include "runtime/stackFrameStream.inline.hpp"
  81 #include "runtime/stackWatermarkSet.hpp"
  82 #include "runtime/synchronizer.hpp"
  83 #include "runtime/threadCritical.hpp"
  84 #include "runtime/threadSMR.inline.hpp"
  85 #include "runtime/threadStatisticalInfo.hpp"
  86 #include "runtime/threadWXSetters.inline.hpp"
  87 #include "runtime/timer.hpp"
  88 #include "runtime/timerTrace.hpp"
  89 #include "runtime/vframe.inline.hpp"
  90 #include "runtime/vframeArray.hpp"
  91 #include "runtime/vframe_hp.hpp"
  92 #include "runtime/vmThread.hpp"
  93 #include "runtime/vmOperations.hpp"
  94 #include "services/threadService.hpp"
  95 #include "utilities/copy.hpp"
  96 #include "utilities/defaultStream.hpp"
  97 #include "utilities/dtrace.hpp"
  98 #include "utilities/events.hpp"
  99 #include "utilities/macros.hpp"
 100 #include "utilities/preserveException.hpp"
 101 #include "utilities/spinYield.hpp"
 102 #if INCLUDE_JVMCI
 103 #include "jvmci/jvmci.hpp"
 104 #include "jvmci/jvmciEnv.hpp"
 105 #endif
 106 #if INCLUDE_JFR
 107 #include "jfr/jfr.hpp"
 108 #endif
 109 
 110 // Set by os layer.
 111 size_t      JavaThread::_stack_size_at_create = 0;
 112 
 113 #ifdef DTRACE_ENABLED
 114 
 115 // Only bother with this argument setup if dtrace is available
 116 
 117   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 118   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 119 
 120   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 121     {                                                                      \
 122       ResourceMark rm(this);                                               \
 123       int len = 0;                                                         \
 124       const char* name = (javathread)->name();                             \
 125       len = strlen(name);                                                  \
 126       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 127         (char *) name, len,                                                \
 128         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 129         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 130         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 131     }
 132 
 133 #else //  ndef DTRACE_ENABLED
 134 
 135   #define DTRACE_THREAD_PROBE(probe, javathread)
 136 
 137 #endif // ndef DTRACE_ENABLED
 138 
 139 void JavaThread::smr_delete() {
 140   if (_on_thread_list) {
 141     ThreadsSMRSupport::smr_delete(this);
 142   } else {
 143     delete this;
 144   }
 145 }
 146 
 147 // Initialized by VMThread at vm_global_init
 148 OopStorage* JavaThread::_thread_oop_storage = NULL;
 149 
 150 OopStorage* JavaThread::thread_oop_storage() {
 151   assert(_thread_oop_storage != NULL, "not yet initialized");
 152   return _thread_oop_storage;
 153 }
 154 
 155 void JavaThread::set_threadOopHandles(oop p) {
 156   assert(_thread_oop_storage != NULL, "not yet initialized");
 157   _threadObj   = OopHandle(_thread_oop_storage, p);
 158   _vthread     = OopHandle(_thread_oop_storage, p);
 159   _jvmti_vthread = OopHandle(_thread_oop_storage, NULL);
 160   _extentLocalCache = OopHandle(_thread_oop_storage, NULL);
 161 }
 162 
 163 oop JavaThread::threadObj() const {
 164   // Ideally we would verify the current thread is oop_safe when this is called, but as we can
 165   // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
 166   // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
 167   // Instead callers must verify oop safe access.
 168   return _threadObj.resolve();
 169 }
 170 
 171 oop JavaThread::vthread() const {
 172   return _vthread.resolve();
 173 }
 174 
 175 void JavaThread::set_vthread(oop p) {
 176   assert(_thread_oop_storage != NULL, "not yet initialized");
 177   _vthread.replace(p);
 178 }
 179 
 180 oop JavaThread::jvmti_vthread() const {
 181   return _jvmti_vthread.resolve();
 182 }
 183 
 184 void JavaThread::set_jvmti_vthread(oop p) {
 185   assert(_thread_oop_storage != NULL, "not yet initialized");
 186   _jvmti_vthread.replace(p);
 187 }
 188 
 189 oop JavaThread::extentLocalCache() const {
 190   return _extentLocalCache.resolve();
 191 }
 192 
 193 void JavaThread::set_extentLocalCache(oop p) {
 194   assert(_thread_oop_storage != NULL, "not yet initialized");
 195   _extentLocalCache.replace(p);
 196 }
 197 
 198 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 199                                     bool daemon, TRAPS) {
 200   assert(thread_group.not_null(), "thread group should be specified");
 201   assert(threadObj() == NULL, "should only create Java thread object once");
 202 
 203   InstanceKlass* ik = vmClasses::Thread_klass();
 204   assert(ik->is_initialized(), "must be");
 205   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 206 
 207   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 208   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 209   // constructor calls Thread.current(), which must be set here.
 210   java_lang_Thread::set_thread(thread_oop(), this);
 211   set_threadOopHandles(thread_oop());
 212 
 213   JavaValue result(T_VOID);
 214   if (thread_name != NULL) {
 215     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 216     // Thread gets assigned specified name and null target
 217     JavaCalls::call_special(&result,
 218                             thread_oop,
 219                             ik,
 220                             vmSymbols::object_initializer_name(),
 221                             vmSymbols::threadgroup_string_void_signature(),
 222                             thread_group,
 223                             name,
 224                             THREAD);
 225   } else {
 226     // Thread gets assigned name "Thread-nnn" and null target
 227     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 228     JavaCalls::call_special(&result,
 229                             thread_oop,
 230                             ik,
 231                             vmSymbols::object_initializer_name(),
 232                             vmSymbols::threadgroup_runnable_void_signature(),
 233                             thread_group,
 234                             Handle(),
 235                             THREAD);
 236   }
 237   os::set_priority(this, NormPriority);
 238 
 239   if (daemon) {
 240     java_lang_Thread::set_daemon(thread_oop());
 241   }
 242 }
 243 
 244 // ======= JavaThread ========
 245 
 246 #if INCLUDE_JVMCI
 247 
 248 jlong* JavaThread::_jvmci_old_thread_counters;
 249 
 250 bool jvmci_counters_include(JavaThread* thread) {
 251   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 252 }
 253 
 254 void JavaThread::collect_counters(jlong* array, int length) {
 255   assert(length == JVMCICounterSize, "wrong value");
 256   for (int i = 0; i < length; i++) {
 257     array[i] = _jvmci_old_thread_counters[i];
 258   }
 259   for (JavaThread* tp : ThreadsListHandle()) {
 260     if (jvmci_counters_include(tp)) {
 261       for (int i = 0; i < length; i++) {
 262         array[i] += tp->_jvmci_counters[i];
 263       }
 264     }
 265   }
 266 }
 267 
 268 // Attempt to enlarge the array for per thread counters.
 269 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 270   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 271   if (new_counters == NULL) {
 272     return NULL;
 273   }
 274   if (old_counters == NULL) {
 275     old_counters = new_counters;
 276     memset(old_counters, 0, sizeof(jlong) * new_size);
 277   } else {
 278     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 279       new_counters[i] = old_counters[i];
 280     }
 281     if (new_size > current_size) {
 282       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 283     }
 284     FREE_C_HEAP_ARRAY(jlong, old_counters);
 285   }
 286   return new_counters;
 287 }
 288 
 289 // Attempt to enlarge the array for per thread counters.
 290 bool JavaThread::resize_counters(int current_size, int new_size) {
 291   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 292   if (new_counters == NULL) {
 293     return false;
 294   } else {
 295     _jvmci_counters = new_counters;
 296     return true;
 297   }
 298 }
 299 
 300 class VM_JVMCIResizeCounters : public VM_Operation {
 301  private:
 302   int _new_size;
 303   bool _failed;
 304 
 305  public:
 306   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 307   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 308   bool allow_nested_vm_operations() const        { return true; }
 309   void doit() {
 310     // Resize the old thread counters array
 311     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 312     if (new_counters == NULL) {
 313       _failed = true;
 314       return;
 315     } else {
 316       JavaThread::_jvmci_old_thread_counters = new_counters;
 317     }
 318 
 319     // Now resize each threads array
 320     for (JavaThread* tp : ThreadsListHandle()) {
 321       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 322         _failed = true;
 323         break;
 324       }
 325     }
 326     if (!_failed) {
 327       JVMCICounterSize = _new_size;
 328     }
 329   }
 330 
 331   bool failed() { return _failed; }
 332 };
 333 
 334 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 335   VM_JVMCIResizeCounters op(new_size);
 336   VMThread::execute(&op);
 337   return !op.failed();
 338 }
 339 
 340 #endif // INCLUDE_JVMCI
 341 
 342 #ifdef ASSERT
 343 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 344 void JavaThread::check_possible_safepoint() {
 345   if (_no_safepoint_count > 0) {
 346     print_owned_locks();
 347     assert(false, "Possible safepoint reached by thread that does not allow it");
 348   }
 349 #ifdef CHECK_UNHANDLED_OOPS
 350   // Clear unhandled oops in JavaThreads so we get a crash right away.
 351   clear_unhandled_oops();
 352 #endif // CHECK_UNHANDLED_OOPS
 353 
 354   // Macos/aarch64 should be in the right state for safepoint (e.g.
 355   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 356   // happens in practice, making such issues hard to find and reproduce.
 357 #if defined(__APPLE__) && defined(AARCH64)
 358   if (AssertWXAtThreadSync) {
 359     assert_wx_state(WXWrite);
 360   }
 361 #endif
 362 }
 363 
 364 void JavaThread::check_for_valid_safepoint_state() {
 365   // Check NoSafepointVerifier, which is implied by locks taken that can be
 366   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 367   // are held.
 368   check_possible_safepoint();
 369 
 370   if (thread_state() != _thread_in_vm) {
 371     fatal("LEAF method calling lock?");
 372   }
 373 
 374   if (GCALotAtAllSafepoints) {
 375     // We could enter a safepoint here and thus have a gc
 376     InterfaceSupport::check_gc_alot();
 377   }
 378 }
 379 #endif // ASSERT
 380 
 381 // A JavaThread is a normal Java thread
 382 
 383 JavaThread::JavaThread() :
 384   // Initialize fields
 385 
 386   _in_asgct(false),
 387   _on_thread_list(false),
 388   DEBUG_ONLY(_java_call_counter(0) COMMA)
 389   _entry_point(nullptr),
 390   _deopt_mark(nullptr),
 391   _deopt_nmethod(nullptr),
 392   _vframe_array_head(nullptr),
 393   _vframe_array_last(nullptr),
 394   _jvmti_deferred_updates(nullptr),
 395   _callee_target(nullptr),
 396   _vm_result(nullptr),
 397   _vm_result_2(nullptr),
 398 
 399   _current_pending_monitor(NULL),
 400   _current_pending_monitor_is_from_java(true),
 401   _current_waiting_monitor(NULL),
 402   _active_handles(NULL),
 403   _free_handle_block(NULL),
 404   _Stalled(0),
 405 
 406   _monitor_chunks(nullptr),
 407 
 408   _suspend_flags(0),
 409 
 410   _thread_state(_thread_new),
 411   _saved_exception_pc(nullptr),
 412 #ifdef ASSERT
 413   _no_safepoint_count(0),
 414   _visited_for_critical_count(false),
 415 #endif
 416 
 417   _terminated(_not_terminated),
 418   _in_deopt_handler(0),
 419   _doing_unsafe_access(false),
 420   _do_not_unlock_if_synchronized(false),
 421 #if INCLUDE_JVMTI
 422   _carrier_thread_suspended(false),
 423   _is_in_VTMS_transition(false),
 424   _is_in_tmp_VTMS_transition(false),
 425 #ifdef ASSERT
 426   _is_VTMS_transition_disabler(false),
 427 #endif
 428 #endif
 429   _jni_attach_state(_not_attaching_via_jni),
 430 #if INCLUDE_JVMCI
 431   _pending_deoptimization(-1),
 432   _pending_monitorenter(false),
 433   _pending_transfer_to_interpreter(false),
 434   _in_retryable_allocation(false),
 435   _pending_failed_speculation(0),
 436   _jvmci{nullptr},
 437   _libjvmci_runtime(nullptr),
 438   _jvmci_counters(nullptr),
 439   _jvmci_reserved0(0),
 440   _jvmci_reserved1(0),
 441   _jvmci_reserved_oop0(nullptr),
 442 #endif // INCLUDE_JVMCI
 443 
 444   _exception_oop(oop()),
 445   _exception_pc(0),
 446   _exception_handler_pc(0),
 447   _is_method_handle_return(0),
 448 
 449   _jni_active_critical(0),
 450   _pending_jni_exception_check_fn(nullptr),
 451   _depth_first_number(0),
 452 
 453   // JVMTI PopFrame support
 454   _popframe_condition(popframe_inactive),
 455   _frames_to_pop_failed_realloc(0),
 456 
 457   _cont_entry(nullptr),
 458   _cont_fastpath(0),
 459   _cont_fastpath_thread_state(1),
 460   _held_monitor_count(0),
 461   _jni_monitor_count(0),
 462 
 463   _handshake(this),
 464 
 465   _popframe_preserved_args(nullptr),
 466   _popframe_preserved_args_size(0),
 467 
 468   _jvmti_thread_state(nullptr),
 469   _interp_only_mode(0),
 470   _should_post_on_exceptions_flag(JNI_FALSE),
 471   _thread_stat(new ThreadStatistics()),
 472 
 473   _parker(),
 474 
 475   _class_to_be_initialized(nullptr),
 476 
 477   _SleepEvent(ParkEvent::Allocate(this))
 478 {
 479   set_jni_functions(jni_functions());
 480 
 481 #if INCLUDE_JVMCI
 482   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
 483   if (JVMCICounterSize > 0) {
 484     resize_counters(0, (int) JVMCICounterSize);
 485   }
 486 #endif // INCLUDE_JVMCI
 487 
 488   // Setup safepoint state info for this thread
 489   ThreadSafepointState::create(this);
 490 
 491   SafepointMechanism::initialize_header(this);
 492 
 493   set_requires_cross_modify_fence(false);
 494 
 495   pd_initialize();
 496   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
 497 }
 498 
 499 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
 500   if (is_attaching_via_jni) {
 501     _jni_attach_state = _attaching_via_jni;
 502   }
 503 }
 504 
 505 
 506 // interrupt support
 507 
 508 void JavaThread::interrupt() {
 509   // All callers should have 'this' thread protected by a
 510   // ThreadsListHandle so that it cannot terminate and deallocate
 511   // itself.
 512   debug_only(check_for_dangling_thread_pointer(this);)
 513 
 514   // For Windows _interrupt_event
 515   WINDOWS_ONLY(osthread()->set_interrupted(true);)
 516 
 517   // For Thread.sleep
 518   _SleepEvent->unpark();
 519 
 520   // For JSR166 LockSupport.park
 521   parker()->unpark();
 522 
 523   // For ObjectMonitor and JvmtiRawMonitor
 524   _ParkEvent->unpark();
 525 }
 526 
 527 
 528 bool JavaThread::is_interrupted(bool clear_interrupted) {
 529   debug_only(check_for_dangling_thread_pointer(this);)
 530 
 531   if (_threadObj.peek() == NULL) {
 532     // If there is no j.l.Thread then it is impossible to have
 533     // been interrupted. We can find NULL during VM initialization
 534     // or when a JNI thread is still in the process of attaching.
 535     // In such cases this must be the current thread.
 536     assert(this == Thread::current(), "invariant");
 537     return false;
 538   }
 539 
 540   bool interrupted = java_lang_Thread::interrupted(threadObj());
 541 
 542   // NOTE that since there is no "lock" around the interrupt and
 543   // is_interrupted operations, there is the possibility that the
 544   // interrupted flag will be "false" but that the
 545   // low-level events will be in the signaled state. This is
 546   // intentional. The effect of this is that Object.wait() and
 547   // LockSupport.park() will appear to have a spurious wakeup, which
 548   // is allowed and not harmful, and the possibility is so rare that
 549   // it is not worth the added complexity to add yet another lock.
 550   // For the sleep event an explicit reset is performed on entry
 551   // to JavaThread::sleep, so there is no early return. It has also been
 552   // recommended not to put the interrupted flag into the "event"
 553   // structure because it hides the issue.
 554   // Also, because there is no lock, we must only clear the interrupt
 555   // state if we are going to report that we were interrupted; otherwise
 556   // an interrupt that happens just after we read the field would be lost.
 557   if (interrupted && clear_interrupted) {
 558     assert(this == Thread::current(), "only the current thread can clear");
 559     java_lang_Thread::set_interrupted(threadObj(), false);
 560     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 561   }
 562 
 563   return interrupted;
 564 }
 565 
 566 void JavaThread::block_if_vm_exited() {
 567   if (_terminated == _vm_exited) {
 568     // _vm_exited is set at safepoint, and Threads_lock is never released
 569     // so we will block here forever.
 570     // Here we can be doing a jump from a safe state to an unsafe state without
 571     // proper transition, but it happens after the final safepoint has begun so
 572     // this jump won't cause any safepoint problems.
 573     set_thread_state(_thread_in_vm);
 574     Threads_lock->lock();
 575     ShouldNotReachHere();
 576   }
 577 }
 578 
 579 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
 580   _jni_attach_state = _not_attaching_via_jni;
 581   set_entry_point(entry_point);
 582   // Create the native thread itself.
 583   // %note runtime_23
 584   os::ThreadType thr_type = os::java_thread;
 585   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
 586                                                             os::java_thread;
 587   os::create_thread(this, thr_type, stack_sz);
 588   // The _osthread may be NULL here because we ran out of memory (too many threads active).
 589   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
 590   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
 591   // the exception consists of creating the exception object & initializing it, initialization
 592   // will leave the VM via a JavaCall and then all locks must be unlocked).
 593   //
 594   // The thread is still suspended when we reach here. Thread must be explicit started
 595   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
 596   // by calling Threads:add. The reason why this is not done here, is because the thread
 597   // object must be fully initialized (take a look at JVM_Start)
 598 }
 599 
 600 JavaThread::~JavaThread() {
 601 
 602   // Enqueue OopHandles for release by the service thread.
 603   add_oop_handles_for_release();
 604 
 605   // Return the sleep event to the free list
 606   ParkEvent::Release(_SleepEvent);
 607   _SleepEvent = NULL;
 608 
 609   // Free any remaining  previous UnrollBlock
 610   vframeArray* old_array = vframe_array_last();
 611 
 612   if (old_array != NULL) {
 613     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
 614     old_array->set_unroll_block(NULL);
 615     delete old_info;
 616     delete old_array;
 617   }
 618 
 619   JvmtiDeferredUpdates* updates = deferred_updates();
 620   if (updates != NULL) {
 621     // This can only happen if thread is destroyed before deoptimization occurs.
 622     assert(updates->count() > 0, "Updates holder not deleted");
 623     // free deferred updates.
 624     delete updates;
 625     set_deferred_updates(NULL);
 626   }
 627 
 628   // All Java related clean up happens in exit
 629   ThreadSafepointState::destroy(this);
 630   if (_thread_stat != NULL) delete _thread_stat;
 631 
 632 #if INCLUDE_JVMCI
 633   if (JVMCICounterSize > 0) {
 634     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
 635   }
 636 #endif // INCLUDE_JVMCI
 637 }
 638 
 639 
 640 // First JavaThread specific code executed by a new Java thread.
 641 void JavaThread::pre_run() {
 642   // empty - see comments in run()
 643 }
 644 
 645 // The main routine called by a new Java thread. This isn't overridden
 646 // by subclasses, instead different subclasses define a different "entry_point"
 647 // which defines the actual logic for that kind of thread.
 648 void JavaThread::run() {
 649   // initialize thread-local alloc buffer related fields
 650   initialize_tlab();
 651 
 652   _stack_overflow_state.create_stack_guard_pages();
 653 
 654   cache_global_variables();
 655 
 656   // Thread is now sufficiently initialized to be handled by the safepoint code as being
 657   // in the VM. Change thread state from _thread_new to _thread_in_vm
 658   assert(this->thread_state() == _thread_new, "wrong thread state");
 659   set_thread_state(_thread_in_vm);
 660 
 661   // Before a thread is on the threads list it is always safe, so after leaving the
 662   // _thread_new we should emit a instruction barrier. The distance to modified code
 663   // from here is probably far enough, but this is consistent and safe.
 664   OrderAccess::cross_modify_fence();
 665 
 666   assert(JavaThread::current() == this, "sanity check");
 667   assert(!Thread::current()->owns_locks(), "sanity check");
 668 
 669   DTRACE_THREAD_PROBE(start, this);
 670 
 671   // This operation might block. We call that after all safepoint checks for a new thread has
 672   // been completed.
 673   set_active_handles(JNIHandleBlock::allocate_block());
 674 
 675   if (JvmtiExport::should_post_thread_life()) {
 676     JvmtiExport::post_thread_start(this);
 677 
 678   }
 679 
 680   // We call another function to do the rest so we are sure that the stack addresses used
 681   // from there will be lower than the stack base just computed.
 682   thread_main_inner();
 683 }
 684 
 685 void JavaThread::thread_main_inner() {
 686   assert(JavaThread::current() == this, "sanity check");
 687   assert(_threadObj.peek() != NULL, "just checking");
 688 
 689   // Execute thread entry point unless this thread has a pending exception.
 690   // Note: Due to JVMTI StopThread we can have pending exceptions already!
 691   if (!this->has_pending_exception()) {
 692     {
 693       ResourceMark rm(this);
 694       this->set_native_thread_name(this->name());
 695     }
 696     HandleMark hm(this);
 697     this->entry_point()(this, this);
 698   }
 699 
 700   DTRACE_THREAD_PROBE(stop, this);
 701 
 702   // Cleanup is handled in post_run()
 703 }
 704 
 705 // Shared teardown for all JavaThreads
 706 void JavaThread::post_run() {
 707   this->exit(false);
 708   this->unregister_thread_stack_with_NMT();
 709   // Defer deletion to here to ensure 'this' is still referenceable in call_run
 710   // for any shared tear-down.
 711   this->smr_delete();
 712 }
 713 
 714 static void ensure_join(JavaThread* thread) {
 715   // We do not need to grab the Threads_lock, since we are operating on ourself.
 716   Handle threadObj(thread, thread->threadObj());
 717   assert(threadObj.not_null(), "java thread object must exist");
 718   ObjectLocker lock(threadObj, thread);
 719   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
 720   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
 721   // Clear the native thread instance - this makes isAlive return false and allows the join()
 722   // to complete once we've done the notify_all below
 723   java_lang_Thread::set_thread(threadObj(), NULL);
 724   lock.notify_all(thread);
 725   // Ignore pending exception, since we are exiting anyway
 726   thread->clear_pending_exception();
 727 }
 728 
 729 static bool is_daemon(oop threadObj) {
 730   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
 731 }
 732 
 733 // For any new cleanup additions, please check to see if they need to be applied to
 734 // cleanup_failed_attach_current_thread as well.
 735 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
 736   assert(this == JavaThread::current(), "thread consistency check");
 737   assert(!is_exiting(), "should not be exiting or terminated already");
 738 
 739   elapsedTimer _timer_exit_phase1;
 740   elapsedTimer _timer_exit_phase2;
 741   elapsedTimer _timer_exit_phase3;
 742   elapsedTimer _timer_exit_phase4;
 743 
 744   if (log_is_enabled(Debug, os, thread, timer)) {
 745     _timer_exit_phase1.start();
 746   }
 747 
 748   HandleMark hm(this);
 749   Handle uncaught_exception(this, this->pending_exception());
 750   this->clear_pending_exception();
 751   Handle threadObj(this, this->threadObj());
 752   assert(threadObj.not_null(), "Java thread object should be created");
 753 
 754   if (!destroy_vm) {
 755     if (uncaught_exception.not_null()) {
 756       EXCEPTION_MARK;
 757       // Call method Thread.dispatchUncaughtException().
 758       Klass* thread_klass = vmClasses::Thread_klass();
 759       JavaValue result(T_VOID);
 760       JavaCalls::call_virtual(&result,
 761                               threadObj, thread_klass,
 762                               vmSymbols::dispatchUncaughtException_name(),
 763                               vmSymbols::throwable_void_signature(),
 764                               uncaught_exception,
 765                               THREAD);
 766       if (HAS_PENDING_EXCEPTION) {
 767         ResourceMark rm(this);
 768         jio_fprintf(defaultStream::error_stream(),
 769                     "\nException: %s thrown from the UncaughtExceptionHandler"
 770                     " in thread \"%s\"\n",
 771                     pending_exception()->klass()->external_name(),
 772                     name());
 773         CLEAR_PENDING_EXCEPTION;
 774       }
 775     }
 776 
 777     if (!is_Compiler_thread()) {
 778       // We have finished executing user-defined Java code and now have to do the
 779       // implementation specific clean-up by calling Thread.exit(). We prevent any
 780       // asynchronous exceptions from being delivered while in Thread.exit()
 781       // to ensure the clean-up is not corrupted.
 782       NoAsyncExceptionDeliveryMark _no_async(this);
 783 
 784       EXCEPTION_MARK;
 785       JavaValue result(T_VOID);
 786       Klass* thread_klass = vmClasses::Thread_klass();
 787       JavaCalls::call_virtual(&result,
 788                               threadObj, thread_klass,
 789                               vmSymbols::exit_method_name(),
 790                               vmSymbols::void_method_signature(),
 791                               THREAD);
 792       CLEAR_PENDING_EXCEPTION;
 793     }
 794 
 795     // notify JVMTI
 796     if (JvmtiExport::should_post_thread_life()) {
 797       JvmtiExport::post_thread_end(this);
 798     }
 799   } else {
 800     // before_exit() has already posted JVMTI THREAD_END events
 801   }
 802 
 803   // Cleanup any pending async exception now since we cannot access oops after
 804   // BarrierSet::barrier_set()->on_thread_detach() has been executed.
 805   if (has_async_exception_condition()) {
 806     handshake_state()->clean_async_exception_operation();
 807   }
 808 
 809   // The careful dance between thread suspension and exit is handled here.
 810   // Since we are in thread_in_vm state and suspension is done with handshakes,
 811   // we can just put in the exiting state and it will be correctly handled.
 812   // Also, no more async exceptions will be added to the queue after this point.
 813   set_terminated(_thread_exiting);
 814   ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
 815 
 816   if (log_is_enabled(Debug, os, thread, timer)) {
 817     _timer_exit_phase1.stop();
 818     _timer_exit_phase2.start();
 819   }
 820 
 821   // Capture daemon status before the thread is marked as terminated.
 822   bool daemon = is_daemon(threadObj());
 823 
 824   // Notify waiters on thread object. This has to be done after exit() is called
 825   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
 826   // group should have the destroyed bit set before waiters are notified).
 827   ensure_join(this);
 828   assert(!this->has_pending_exception(), "ensure_join should have cleared");
 829 
 830   if (log_is_enabled(Debug, os, thread, timer)) {
 831     _timer_exit_phase2.stop();
 832     _timer_exit_phase3.start();
 833   }
 834   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
 835   // held by this thread must be released. The spec does not distinguish
 836   // between JNI-acquired and regular Java monitors. We can only see
 837   // regular Java monitors here if monitor enter-exit matching is broken.
 838   //
 839   // ensure_join() ignores IllegalThreadStateExceptions, and so does
 840   // ObjectSynchronizer::release_monitors_owned_by_thread().
 841   if (exit_type == jni_detach) {
 842     // Sanity check even though JNI DetachCurrentThread() would have
 843     // returned JNI_ERR if there was a Java frame. JavaThread exit
 844     // should be done executing Java code by the time we get here.
 845     assert(!this->has_last_Java_frame(),
 846            "should not have a Java frame when detaching or exiting");
 847     ObjectSynchronizer::release_monitors_owned_by_thread(this);
 848     assert(!this->has_pending_exception(), "release_monitors should have cleared");
 849   }
 850 
 851   // Since above code may not release JNI monitors and if someone forgot to do an
 852   // JNI monitorexit, held count should be equal jni count.
 853   // Consider scan all object monitor for this owner if JNI count > 0 (at least on detach).
 854   assert(this->held_monitor_count() == this->jni_monitor_count(),
 855          "held monitor count should be equal to jni: " INT64_FORMAT " != " INT64_FORMAT,
 856          (int64_t)this->held_monitor_count(), (int64_t)this->jni_monitor_count());
 857   if (CheckJNICalls && this->jni_monitor_count() > 0) {
 858     // We would like a fatal here, but due to we never checked this before there
 859     // is a lot of tests which breaks, even with an error log.
 860     log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
 861       exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
 862   }
 863 
 864   // These things needs to be done while we are still a Java Thread. Make sure that thread
 865   // is in a consistent state, in case GC happens
 866   JFR_ONLY(Jfr::on_thread_exit(this);)
 867 
 868   if (active_handles() != NULL) {
 869     JNIHandleBlock* block = active_handles();
 870     set_active_handles(NULL);
 871     JNIHandleBlock::release_block(block);
 872   }
 873 
 874   if (free_handle_block() != NULL) {
 875     JNIHandleBlock* block = free_handle_block();
 876     set_free_handle_block(NULL);
 877     JNIHandleBlock::release_block(block);
 878   }
 879 
 880   // These have to be removed while this is still a valid thread.
 881   _stack_overflow_state.remove_stack_guard_pages();
 882 
 883   if (UseTLAB) {
 884     tlab().retire();
 885   }
 886 
 887   if (JvmtiEnv::environments_might_exist()) {
 888     JvmtiExport::cleanup_thread(this);
 889   }
 890 
 891   // We need to cache the thread name for logging purposes below as once
 892   // we have called on_thread_detach this thread must not access any oops.
 893   char* thread_name = NULL;
 894   if (log_is_enabled(Debug, os, thread, timer)) {
 895     ResourceMark rm(this);
 896     thread_name = os::strdup(name());
 897   }
 898 
 899   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
 900     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
 901     os::current_thread_id());
 902 
 903   if (log_is_enabled(Debug, os, thread, timer)) {
 904     _timer_exit_phase3.stop();
 905     _timer_exit_phase4.start();
 906   }
 907 
 908 #if INCLUDE_JVMCI
 909   if (JVMCICounterSize > 0) {
 910     if (jvmci_counters_include(this)) {
 911       for (int i = 0; i < JVMCICounterSize; i++) {
 912         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
 913       }
 914     }
 915   }
 916 #endif // INCLUDE_JVMCI
 917 
 918   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
 919   // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
 920   Threads::remove(this, daemon);
 921 
 922   if (log_is_enabled(Debug, os, thread, timer)) {
 923     _timer_exit_phase4.stop();
 924     log_debug(os, thread, timer)("name='%s'"
 925                                  ", exit-phase1=" JLONG_FORMAT
 926                                  ", exit-phase2=" JLONG_FORMAT
 927                                  ", exit-phase3=" JLONG_FORMAT
 928                                  ", exit-phase4=" JLONG_FORMAT,
 929                                  thread_name,
 930                                  _timer_exit_phase1.milliseconds(),
 931                                  _timer_exit_phase2.milliseconds(),
 932                                  _timer_exit_phase3.milliseconds(),
 933                                  _timer_exit_phase4.milliseconds());
 934     os::free(thread_name);
 935   }
 936 }
 937 
 938 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
 939   if (active_handles() != NULL) {
 940     JNIHandleBlock* block = active_handles();
 941     set_active_handles(NULL);
 942     JNIHandleBlock::release_block(block);
 943   }
 944 
 945   if (free_handle_block() != NULL) {
 946     JNIHandleBlock* block = free_handle_block();
 947     set_free_handle_block(NULL);
 948     JNIHandleBlock::release_block(block);
 949   }
 950 
 951   // These have to be removed while this is still a valid thread.
 952   _stack_overflow_state.remove_stack_guard_pages();
 953 
 954   if (UseTLAB) {
 955     tlab().retire();
 956   }
 957 
 958   Threads::remove(this, is_daemon);
 959   this->smr_delete();
 960 }
 961 
 962 JavaThread* JavaThread::active() {
 963   Thread* thread = Thread::current();
 964   if (thread->is_Java_thread()) {
 965     return JavaThread::cast(thread);
 966   } else {
 967     assert(thread->is_VM_thread(), "this must be a vm thread");
 968     VM_Operation* op = ((VMThread*) thread)->vm_operation();
 969     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
 970     return ret;
 971   }
 972 }
 973 
 974 bool JavaThread::is_lock_owned(address adr) const {
 975   if (Thread::is_lock_owned(adr)) return true;
 976 
 977   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
 978     if (chunk->contains(adr)) return true;
 979   }
 980 
 981   return false;
 982 }
 983 
 984 bool JavaThread::is_lock_owned_current(address adr) const {
 985   address stack_end = _stack_base - _stack_size;
 986   const ContinuationEntry* ce = vthread_continuation();
 987   address stack_base = ce != nullptr ? (address)ce->entry_sp() : _stack_base;
 988   if (stack_base > adr && adr >= stack_end) {
 989     return true;
 990   }
 991 
 992   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
 993     if (chunk->contains(adr)) {
 994       return true;
 995     }
 996   }
 997 
 998   return false;
 999 }
1000 
1001 bool JavaThread::is_lock_owned_carrier(address adr) const {
1002   assert(is_vthread_mounted(), "");
1003   address stack_end = _stack_base - _stack_size;
1004   address stack_base = (address)vthread_continuation()->entry_sp();
1005   return stack_base > adr && adr >= stack_end;
1006 }
1007 
1008 oop JavaThread::exception_oop() const {
1009   return Atomic::load(&_exception_oop);
1010 }
1011 
1012 void JavaThread::set_exception_oop(oop o) {
1013   Atomic::store(&_exception_oop, o);
1014 }
1015 
1016 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1017   chunk->set_next(monitor_chunks());
1018   set_monitor_chunks(chunk);
1019 }
1020 
1021 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1022   guarantee(monitor_chunks() != NULL, "must be non empty");
1023   if (monitor_chunks() == chunk) {
1024     set_monitor_chunks(chunk->next());
1025   } else {
1026     MonitorChunk* prev = monitor_chunks();
1027     while (prev->next() != chunk) prev = prev->next();
1028     prev->set_next(chunk->next());
1029   }
1030 }
1031 
1032 void JavaThread::handle_special_runtime_exit_condition() {
1033   if (is_obj_deopt_suspend()) {
1034     frame_anchor()->make_walkable();
1035     wait_for_object_deoptimization();
1036   }
1037   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1038 }
1039 
1040 
1041 // Asynchronous exceptions support
1042 //
1043 void JavaThread::handle_async_exception(oop java_throwable) {
1044   assert(java_throwable != NULL, "should have an _async_exception to throw");
1045   assert(!is_at_poll_safepoint(), "should have never called this method");
1046 
1047   if (has_last_Java_frame()) {
1048     frame f = last_frame();
1049     if (f.is_runtime_frame()) {
1050       // If the topmost frame is a runtime stub, then we are calling into
1051       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1052       // must deoptimize the caller before continuing, as the compiled exception
1053       // handler table may not be valid.
1054       RegisterMap reg_map(this,
1055                           RegisterMap::UpdateMap::skip,
1056                           RegisterMap::ProcessFrames::include,
1057                           RegisterMap::WalkContinuation::skip);
1058       frame compiled_frame = f.sender(&reg_map);
1059       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1060         Deoptimization::deoptimize(this, compiled_frame);
1061       }
1062     }
1063   }
1064 
1065   // We cannot call Exceptions::_throw(...) here because we cannot block
1066   set_pending_exception(java_throwable, __FILE__, __LINE__);
1067 
1068   // Clear any extent-local bindings
1069   set_extentLocalCache(NULL);
1070   oop threadOop = threadObj();
1071   assert(threadOop != NULL, "must be");
1072   java_lang_Thread::clear_extentLocalBindings(threadOop);
1073 
1074   LogTarget(Info, exceptions) lt;
1075   if (lt.is_enabled()) {
1076     ResourceMark rm;
1077     LogStream ls(lt);
1078     ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1079     if (has_last_Java_frame()) {
1080       frame f = last_frame();
1081       ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1082     }
1083     ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1084   }
1085 }
1086 
1087 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1088   // Do not throw asynchronous exceptions against the compiler thread
1089   // or if the thread is already exiting.
1090   if (!can_call_java() || is_exiting()) {
1091     delete aeh;
1092     return;
1093   }
1094 
1095   oop exception = aeh->exception();
1096   Handshake::execute(aeh, this);  // Install asynchronous handshake
1097 
1098   ResourceMark rm;
1099   if (log_is_enabled(Info, exceptions)) {
1100     log_info(exceptions)("Pending Async. exception installed of type: %s",
1101                          InstanceKlass::cast(exception->klass())->external_name());
1102   }
1103   // for AbortVMOnException flag
1104   Exceptions::debug_check_abort(exception->klass()->external_name());
1105 
1106   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1107   java_lang_Thread::set_interrupted(threadObj(), true);
1108   this->interrupt();
1109 }
1110 
1111 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1112   AsyncExceptionHandshake* _aeh;
1113 public:
1114   InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1115     HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1116   ~InstallAsyncExceptionHandshake() {
1117     // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1118     delete _aeh;
1119   }
1120   void do_thread(Thread* thr) {
1121     JavaThread* target = JavaThread::cast(thr);
1122     target->install_async_exception(_aeh);
1123     _aeh = nullptr;
1124   }
1125 };
1126 
1127 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1128   OopHandle e(Universe::vm_global(), java_throwable);
1129   InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1130   Handshake::execute(&iaeh, target);
1131 }
1132 
1133 #if INCLUDE_JVMTI
1134 void JavaThread::set_is_in_VTMS_transition(bool val) {
1135   _is_in_VTMS_transition = val;
1136 }
1137 
1138 #ifdef ASSERT
1139 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1140   _is_VTMS_transition_disabler = val;
1141 }
1142 #endif
1143 #endif
1144 
1145 // External suspension mechanism.
1146 //
1147 // Guarantees on return (for a valid target thread):
1148 //   - Target thread will not execute any new bytecode.
1149 //   - Target thread will not enter any new monitors.
1150 //
1151 bool JavaThread::java_suspend() {
1152 #if INCLUDE_JVMTI
1153   // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1154   assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1155   assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1156 #endif
1157 
1158   guarantee(Thread::is_JavaThread_protected(/* target */ this),
1159             "target JavaThread is not protected in calling context.");
1160   return this->handshake_state()->suspend();
1161 }
1162 
1163 bool JavaThread::java_resume() {
1164   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1165             "missing ThreadsListHandle in calling context.");
1166   return this->handshake_state()->resume();
1167 }
1168 
1169 // Wait for another thread to perform object reallocation and relocking on behalf of
1170 // this thread. The current thread is required to change to _thread_blocked in order
1171 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1172 // handshake safe, the other thread can complete the handshake used to synchronize
1173 // with this thread and then perform the reallocation and relocking.
1174 // See EscapeBarrier::sync_and_suspend_*()
1175 
1176 void JavaThread::wait_for_object_deoptimization() {
1177   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1178   assert(this == Thread::current(), "invariant");
1179 
1180   bool spin_wait = os::is_MP();
1181   do {
1182     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1183     // Wait for object deoptimization if requested.
1184     if (spin_wait) {
1185       // A single deoptimization is typically very short. Microbenchmarks
1186       // showed 5% better performance when spinning.
1187       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1188       SpinYield spin(spin_limit);
1189       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1190         spin.wait();
1191       }
1192       // Spin just once
1193       spin_wait = false;
1194     } else {
1195       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1196       if (is_obj_deopt_suspend()) {
1197         ml.wait();
1198       }
1199     }
1200     // A handshake for obj. deoptimization suspend could have been processed so
1201     // we must check after processing.
1202   } while (is_obj_deopt_suspend());
1203 }
1204 
1205 #ifdef ASSERT
1206 // Verify the JavaThread has not yet been published in the Threads::list, and
1207 // hence doesn't need protection from concurrent access at this stage.
1208 void JavaThread::verify_not_published() {
1209   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1210   // since an unpublished JavaThread doesn't participate in the
1211   // Thread-SMR protocol for keeping a ThreadsList alive.
1212   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1213 }
1214 #endif
1215 
1216 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1217 // pending, when _suspend_flags is non-zero or when we need to process a stack
1218 // watermark. Also check for pending async exceptions (except unsafe access error).
1219 // Note only the native==>Java barriers can call this function when thread state
1220 // is _thread_in_native_trans.
1221 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1222   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1223   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1224 
1225   thread->set_thread_state(_thread_in_vm);
1226 
1227   // Enable WXWrite: called directly from interpreter native wrapper.
1228   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1229 
1230   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1231 
1232   // After returning from native, it could be that the stack frames are not
1233   // yet safe to use. We catch such situations in the subsequent stack watermark
1234   // barrier, which will trap unsafe stack frames.
1235   StackWatermarkSet::before_unwind(thread);
1236 }
1237 
1238 #ifndef PRODUCT
1239 // Deoptimization
1240 // Function for testing deoptimization
1241 void JavaThread::deoptimize() {
1242   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1243   bool deopt = false;           // Dump stack only if a deopt actually happens.
1244   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1245   // Iterate over all frames in the thread and deoptimize
1246   for (; !fst.is_done(); fst.next()) {
1247     if (fst.current()->can_be_deoptimized()) {
1248 
1249       if (only_at) {
1250         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1251         // consists of comma or carriage return separated numbers so
1252         // search for the current bci in that string.
1253         address pc = fst.current()->pc();
1254         nmethod* nm =  (nmethod*) fst.current()->cb();
1255         ScopeDesc* sd = nm->scope_desc_at(pc);
1256         char buffer[8];
1257         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1258         size_t len = strlen(buffer);
1259         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1260         while (found != NULL) {
1261           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1262               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1263             // Check that the bci found is bracketed by terminators.
1264             break;
1265           }
1266           found = strstr(found + 1, buffer);
1267         }
1268         if (!found) {
1269           continue;
1270         }
1271       }
1272 
1273       if (DebugDeoptimization && !deopt) {
1274         deopt = true; // One-time only print before deopt
1275         tty->print_cr("[BEFORE Deoptimization]");
1276         trace_frames();
1277         trace_stack();
1278       }
1279       Deoptimization::deoptimize(this, *fst.current());
1280     }
1281   }
1282 
1283   if (DebugDeoptimization && deopt) {
1284     tty->print_cr("[AFTER Deoptimization]");
1285     trace_frames();
1286   }
1287 }
1288 
1289 
1290 // Make zombies
1291 void JavaThread::make_zombies() {
1292   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1293     if (fst.current()->can_be_deoptimized()) {
1294       // it is a Java nmethod
1295       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1296       nm->make_not_entrant();
1297     }
1298   }
1299 }
1300 #endif // PRODUCT
1301 
1302 
1303 void JavaThread::deoptimize_marked_methods() {
1304   if (!has_last_Java_frame()) return;
1305   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1306   for (; !fst.is_done(); fst.next()) {
1307     if (fst.current()->should_be_deoptimized()) {
1308       Deoptimization::deoptimize(this, *fst.current());
1309     }
1310   }
1311 }
1312 
1313 #ifdef ASSERT
1314 void JavaThread::verify_frame_info() {
1315   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1316          (has_last_Java_frame() && java_call_counter() > 0),
1317          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1318          has_last_Java_frame() ? "true" : "false", java_call_counter());
1319 }
1320 #endif
1321 
1322 // Push on a new block of JNI handles.
1323 void JavaThread::push_jni_handle_block() {
1324   // Allocate a new block for JNI handles.
1325   // Inlined code from jni_PushLocalFrame()
1326   JNIHandleBlock* old_handles = active_handles();
1327   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1328   assert(old_handles != NULL && new_handles != NULL, "should not be NULL");
1329   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1330   set_active_handles(new_handles);
1331 }
1332 
1333 // Pop off the current block of JNI handles.
1334 void JavaThread::pop_jni_handle_block() {
1335   // Release our JNI handle block
1336   JNIHandleBlock* old_handles = active_handles();
1337   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1338   assert(new_handles != nullptr, "should never set active handles to null");
1339   set_active_handles(new_handles);
1340   old_handles->set_pop_frame_link(NULL);
1341   JNIHandleBlock::release_block(old_handles, this);
1342 }
1343 
1344 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1345   // Verify that the deferred card marks have been flushed.
1346   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1347 
1348   // Traverse the GCHandles
1349   Thread::oops_do_no_frames(f, cf);
1350 
1351   if (active_handles() != NULL) {
1352     active_handles()->oops_do(f);
1353   }
1354 
1355   DEBUG_ONLY(verify_frame_info();)
1356 
1357   if (has_last_Java_frame()) {
1358     // Traverse the monitor chunks
1359     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1360       chunk->oops_do(f);
1361     }
1362   }
1363 
1364   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1365   // If we have deferred set_locals there might be oops waiting to be
1366   // written
1367   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1368   if (list != NULL) {
1369     for (int i = 0; i < list->length(); i++) {
1370       list->at(i)->oops_do(f);
1371     }
1372   }
1373 
1374   // Traverse instance variables at the end since the GC may be moving things
1375   // around using this function
1376   f->do_oop((oop*) &_vm_result);
1377   f->do_oop((oop*) &_exception_oop);
1378 #if INCLUDE_JVMCI
1379   f->do_oop((oop*) &_jvmci_reserved_oop0);
1380 #endif
1381 
1382   if (jvmti_thread_state() != NULL) {
1383     jvmti_thread_state()->oops_do(f, cf);
1384   }
1385 
1386   // The continuation oops are really on the stack. But there is typically at most
1387   // one of those per thread, so we handle them here in the oops_do_no_frames part
1388   // so that we don't have to sprinkle as many stack watermark checks where these
1389   // oops are used. We just need to make sure the thread has started processing.
1390   ContinuationEntry* entry = _cont_entry;
1391   while (entry != nullptr) {
1392     f->do_oop((oop*)entry->cont_addr());
1393     f->do_oop((oop*)entry->chunk_addr());
1394     entry = entry->parent();
1395   }
1396 }
1397 
1398 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1399   if (!has_last_Java_frame()) {
1400     return;
1401   }
1402   // Finish any pending lazy GC activity for the frames
1403   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1404   // Traverse the execution stack
1405   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1406     fst.current()->oops_do(f, cf, fst.register_map());
1407   }
1408 }
1409 
1410 #ifdef ASSERT
1411 void JavaThread::verify_states_for_handshake() {
1412   // This checks that the thread has a correct frame state during a handshake.
1413   verify_frame_info();
1414 }
1415 #endif
1416 
1417 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1418   DEBUG_ONLY(verify_frame_info();)
1419   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1420 
1421   if (has_last_Java_frame()) {
1422     // Traverse the execution stack
1423     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1424       fst.current()->nmethods_do(cf);
1425     }
1426   }
1427 
1428   if (jvmti_thread_state() != NULL) {
1429     jvmti_thread_state()->nmethods_do(cf);
1430   }
1431 }
1432 
1433 void JavaThread::metadata_do(MetadataClosure* f) {
1434   if (has_last_Java_frame()) {
1435     // Traverse the execution stack to call f() on the methods in the stack
1436     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1437       fst.current()->metadata_do(f);
1438     }
1439   } else if (is_Compiler_thread()) {
1440     // need to walk ciMetadata in current compile tasks to keep alive.
1441     CompilerThread* ct = (CompilerThread*)this;
1442     if (ct->env() != NULL) {
1443       ct->env()->metadata_do(f);
1444     }
1445     CompileTask* task = ct->task();
1446     if (task != NULL) {
1447       task->metadata_do(f);
1448     }
1449   }
1450 }
1451 
1452 // Printing
1453 const char* _get_thread_state_name(JavaThreadState _thread_state) {
1454   switch (_thread_state) {
1455   case _thread_uninitialized:     return "_thread_uninitialized";
1456   case _thread_new:               return "_thread_new";
1457   case _thread_new_trans:         return "_thread_new_trans";
1458   case _thread_in_native:         return "_thread_in_native";
1459   case _thread_in_native_trans:   return "_thread_in_native_trans";
1460   case _thread_in_vm:             return "_thread_in_vm";
1461   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1462   case _thread_in_Java:           return "_thread_in_Java";
1463   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1464   case _thread_blocked:           return "_thread_blocked";
1465   case _thread_blocked_trans:     return "_thread_blocked_trans";
1466   default:                        return "unknown thread state";
1467   }
1468 }
1469 
1470 void JavaThread::print_thread_state_on(outputStream *st) const {
1471   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1472 }
1473 
1474 const char* JavaThread::thread_state_name() const {
1475   return _get_thread_state_name(_thread_state);
1476 }
1477 
1478 // Called by Threads::print() for VM_PrintThreads operation
1479 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1480   st->print_raw("\"");
1481   st->print_raw(name());
1482   st->print_raw("\" ");
1483   oop thread_oop = threadObj();
1484   if (thread_oop != NULL) {
1485     st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1486     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
1487     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1488   }
1489   Thread::print_on(st, print_extended_info);
1490   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1491   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1492   if (thread_oop != NULL) {
1493     if (is_vthread_mounted()) {
1494       oop vt = vthread();
1495       assert(vt != NULL, "");
1496       st->print_cr("   Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1497     } else {
1498       st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1499     }
1500   }
1501 #ifndef PRODUCT
1502   _safepoint_state->print_on(st);
1503 #endif // PRODUCT
1504   if (is_Compiler_thread()) {
1505     CompileTask *task = ((CompilerThread*)this)->task();
1506     if (task != NULL) {
1507       st->print("   Compiling: ");
1508       task->print(st, NULL, true, false);
1509     } else {
1510       st->print("   No compile task");
1511     }
1512     st->cr();
1513   }
1514 }
1515 
1516 void JavaThread::print() const { print_on(tty); }
1517 
1518 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1519   st->print("%s", get_thread_name_string(buf, buflen));
1520 }
1521 
1522 // Called by fatal error handler. The difference between this and
1523 // JavaThread::print() is that we can't grab lock or allocate memory.
1524 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1525   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1526   Thread* current = Thread::current_or_null_safe();
1527   assert(current != nullptr, "cannot be called by a detached thread");
1528   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1529     // Only access threadObj() if current thread is not a JavaThread
1530     // or if it is a JavaThread that can safely access oops.
1531     oop thread_obj = threadObj();
1532     if (thread_obj != nullptr) {
1533       if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
1534     }
1535   }
1536   st->print(" [");
1537   st->print("%s", _get_thread_state_name(_thread_state));
1538   if (osthread()) {
1539     st->print(", id=%d", osthread()->thread_id());
1540   }
1541   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
1542             p2i(stack_end()), p2i(stack_base()));
1543   st->print("]");
1544 
1545   ThreadsSMRSupport::print_info_on(this, st);
1546   return;
1547 }
1548 
1549 
1550 // Verification
1551 
1552 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1553   // ignore if there is no stack
1554   if (!has_last_Java_frame()) return;
1555   // traverse the stack frames. Starts from top frame.
1556   for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1557     frame* fr = fst.current();
1558     f(fr, fst.register_map());
1559   }
1560 }
1561 
1562 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1563 
1564 void JavaThread::verify() {
1565   // Verify oops in the thread.
1566   oops_do(&VerifyOopClosure::verify_oop, NULL);
1567 
1568   // Verify the stack frames.
1569   frames_do(frame_verify);
1570 }
1571 
1572 // CR 6300358 (sub-CR 2137150)
1573 // Most callers of this method assume that it can't return NULL but a
1574 // thread may not have a name whilst it is in the process of attaching to
1575 // the VM - see CR 6412693, and there are places where a JavaThread can be
1576 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1577 // if vm exit occurs during initialization). These cases can all be accounted
1578 // for such that this method never returns NULL.
1579 const char* JavaThread::name() const  {
1580   if (Thread::is_JavaThread_protected(/* target */ this)) {
1581     // The target JavaThread is protected so get_thread_name_string() is safe:
1582     return get_thread_name_string();
1583   }
1584 
1585   // The target JavaThread is not protected so we return the default:
1586   return Thread::name();
1587 }
1588 
1589 // Returns a non-NULL representation of this thread's name, or a suitable
1590 // descriptive string if there is no set name.
1591 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1592   const char* name_str;
1593 #ifdef ASSERT
1594   Thread* current = Thread::current_or_null_safe();
1595   assert(current != nullptr, "cannot be called by a detached thread");
1596   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1597     // Only access threadObj() if current thread is not a JavaThread
1598     // or if it is a JavaThread that can safely access oops.
1599 #endif
1600     oop thread_obj = threadObj();
1601     if (thread_obj != NULL) {
1602       oop name = java_lang_Thread::name(thread_obj);
1603       if (name != NULL) {
1604         if (buf == NULL) {
1605           name_str = java_lang_String::as_utf8_string(name);
1606         } else {
1607           name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1608         }
1609       } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1610         name_str = "<no-name - thread is attaching>";
1611       } else {
1612         name_str = "<un-named>";
1613       }
1614     } else {
1615       name_str = Thread::name();
1616     }
1617 #ifdef ASSERT
1618   } else {
1619     // Current JavaThread has exited...
1620     if (current == this) {
1621       // ... and is asking about itself:
1622       name_str = "<no-name - current JavaThread has exited>";
1623     } else {
1624       // ... and it can't safely determine this JavaThread's name so
1625       // use the default thread name.
1626       name_str = Thread::name();
1627     }
1628   }
1629 #endif
1630   assert(name_str != NULL, "unexpected NULL thread name");
1631   return name_str;
1632 }
1633 
1634 // Helper to extract the name from the thread oop for logging.
1635 const char* JavaThread::name_for(oop thread_obj) {
1636   assert(thread_obj != NULL, "precondition");
1637   oop name = java_lang_Thread::name(thread_obj);
1638   const char* name_str;
1639   if (name != NULL) {
1640     name_str = java_lang_String::as_utf8_string(name);
1641   } else {
1642     name_str = "<un-named>";
1643   }
1644   return name_str;
1645 }
1646 
1647 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1648 
1649   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1650   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1651   // Link Java Thread object <-> C++ Thread
1652 
1653   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1654   // and put it into a new Handle.  The Handle "thread_oop" can then
1655   // be used to pass the C++ thread object to other methods.
1656 
1657   // Set the Java level thread object (jthread) field of the
1658   // new thread (a JavaThread *) to C++ thread object using the
1659   // "thread_oop" handle.
1660 
1661   // Set the thread field (a JavaThread *) of the
1662   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1663 
1664   Handle thread_oop(Thread::current(),
1665                     JNIHandles::resolve_non_null(jni_thread));
1666   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1667          "must be initialized");
1668   set_threadOopHandles(thread_oop());
1669   java_lang_Thread::set_thread(thread_oop(), this);
1670 
1671   if (prio == NoPriority) {
1672     prio = java_lang_Thread::priority(thread_oop());
1673     assert(prio != NoPriority, "A valid priority should be present");
1674   }
1675 
1676   // Push the Java priority down to the native thread; needs Threads_lock
1677   Thread::set_priority(this, prio);
1678 
1679   // Add the new thread to the Threads list and set it in motion.
1680   // We must have threads lock in order to call Threads::add.
1681   // It is crucial that we do not block before the thread is
1682   // added to the Threads list for if a GC happens, then the java_thread oop
1683   // will not be visited by GC.
1684   Threads::add(this);
1685 }
1686 
1687 oop JavaThread::current_park_blocker() {
1688   // Support for JSR-166 locks
1689   oop thread_oop = threadObj();
1690   if (thread_oop != NULL) {
1691     return java_lang_Thread::park_blocker(thread_oop);
1692   }
1693   return NULL;
1694 }
1695 
1696 
1697 void JavaThread::print_stack_on(outputStream* st) {
1698   if (!has_last_Java_frame()) return;
1699 
1700   Thread* current_thread = Thread::current();
1701   ResourceMark rm(current_thread);
1702   HandleMark hm(current_thread);
1703 
1704   RegisterMap reg_map(this,
1705                       RegisterMap::UpdateMap::include,
1706                       RegisterMap::ProcessFrames::include,
1707                       RegisterMap::WalkContinuation::skip);
1708   vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
1709   int count = 0;
1710   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
1711     if (f->is_java_frame()) {
1712       javaVFrame* jvf = javaVFrame::cast(f);
1713       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1714 
1715       // Print out lock information
1716       if (JavaMonitorsInStackTrace) {
1717         jvf->print_lock_info_on(st, count);
1718       }
1719     } else {
1720       // Ignore non-Java frames
1721     }
1722 
1723     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1724     count++;
1725     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1726   }
1727 }
1728 
1729 #if INCLUDE_JVMTI
1730 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1731 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1732   set_jvmti_vthread(thread_oop);
1733 
1734   // unbind current JvmtiThreadState from JavaThread
1735   JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1736 
1737   // bind new JvmtiThreadState to JavaThread
1738   JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1739 
1740   return jvmti_thread_state();
1741 }
1742 #endif
1743 
1744 // JVMTI PopFrame support
1745 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1746   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
1747   if (in_bytes(size_in_bytes) != 0) {
1748     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1749     _popframe_preserved_args_size = in_bytes(size_in_bytes);
1750     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1751   }
1752 }
1753 
1754 void* JavaThread::popframe_preserved_args() {
1755   return _popframe_preserved_args;
1756 }
1757 
1758 ByteSize JavaThread::popframe_preserved_args_size() {
1759   return in_ByteSize(_popframe_preserved_args_size);
1760 }
1761 
1762 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1763   int sz = in_bytes(popframe_preserved_args_size());
1764   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1765   return in_WordSize(sz / wordSize);
1766 }
1767 
1768 void JavaThread::popframe_free_preserved_args() {
1769   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
1770   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1771   _popframe_preserved_args = NULL;
1772   _popframe_preserved_args_size = 0;
1773 }
1774 
1775 #ifndef PRODUCT
1776 
1777 void JavaThread::trace_frames() {
1778   tty->print_cr("[Describe stack]");
1779   int frame_no = 1;
1780   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1781     tty->print("  %d. ", frame_no++);
1782     fst.current()->print_value_on(tty, this);
1783     tty->cr();
1784   }
1785 }
1786 
1787 class PrintAndVerifyOopClosure: public OopClosure {
1788  protected:
1789   template <class T> inline void do_oop_work(T* p) {
1790     oop obj = RawAccess<>::oop_load(p);
1791     if (obj == NULL) return;
1792     tty->print(INTPTR_FORMAT ": ", p2i(p));
1793     if (oopDesc::is_oop_or_null(obj)) {
1794       if (obj->is_objArray()) {
1795         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1796       } else {
1797         obj->print();
1798       }
1799     } else {
1800       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1801     }
1802     tty->cr();
1803   }
1804  public:
1805   virtual void do_oop(oop* p) { do_oop_work(p); }
1806   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
1807 };
1808 
1809 #ifdef ASSERT
1810 // Print or validate the layout of stack frames
1811 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1812   ResourceMark rm;
1813   PreserveExceptionMark pm(this);
1814   FrameValues values;
1815   int frame_no = 0;
1816   for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1817     fst.current()->describe(values, ++frame_no, fst.register_map());
1818     if (depth == frame_no) break;
1819   }
1820   Continuation::describe(values);
1821   if (validate_only) {
1822     values.validate();
1823   } else {
1824     tty->print_cr("[Describe stack layout]");
1825     values.print(this);
1826   }
1827 }
1828 #endif
1829 
1830 void JavaThread::trace_stack_from(vframe* start_vf) {
1831   ResourceMark rm;
1832   int vframe_no = 1;
1833   for (vframe* f = start_vf; f; f = f->sender()) {
1834     if (f->is_java_frame()) {
1835       javaVFrame::cast(f)->print_activation(vframe_no++);
1836     } else {
1837       f->print();
1838     }
1839     if (vframe_no > StackPrintLimit) {
1840       tty->print_cr("...<more frames>...");
1841       return;
1842     }
1843   }
1844 }
1845 
1846 
1847 void JavaThread::trace_stack() {
1848   if (!has_last_Java_frame()) return;
1849   Thread* current_thread = Thread::current();
1850   ResourceMark rm(current_thread);
1851   HandleMark hm(current_thread);
1852   RegisterMap reg_map(this,
1853                       RegisterMap::UpdateMap::include,
1854                       RegisterMap::ProcessFrames::include,
1855                       RegisterMap::WalkContinuation::skip);
1856   trace_stack_from(last_java_vframe(&reg_map));
1857 }
1858 
1859 
1860 #endif // PRODUCT
1861 
1862 void JavaThread::inc_held_monitor_count(int i, bool jni) {
1863 #ifdef SUPPORT_MONITOR_COUNT
1864   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1865   _held_monitor_count += i;
1866   if (jni) {
1867     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1868     _jni_monitor_count += i;
1869   }
1870 #endif
1871 }
1872 
1873 void JavaThread::dec_held_monitor_count(int i, bool jni) {
1874 #ifdef SUPPORT_MONITOR_COUNT
1875   _held_monitor_count -= i;
1876   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1877   if (jni) {
1878     _jni_monitor_count -= i;
1879     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1880   }
1881 #endif
1882 }
1883 
1884 frame JavaThread::vthread_last_frame() {
1885   assert (is_vthread_mounted(), "Virtual thread not mounted");
1886   return last_frame();
1887 }
1888 
1889 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1890   const ContinuationEntry* entry = vthread_continuation();
1891   guarantee (entry != NULL, "Not a carrier thread");
1892   frame f = entry->to_frame();
1893   if (reg_map->process_frames()) {
1894     entry->flush_stack_processing(this);
1895   }
1896   entry->update_register_map(reg_map);
1897   return f.sender(reg_map);
1898 }
1899 
1900 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1901   return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1902 }
1903 
1904 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
1905   assert(reg_map != NULL, "a map must be given");
1906   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
1907     if (vf->is_java_frame()) return javaVFrame::cast(vf);
1908   }
1909   return NULL;
1910 }
1911 
1912 oop JavaThread::get_continuation() const {
1913   assert(threadObj() != nullptr, "must be set");
1914   return java_lang_Thread::continuation(threadObj());
1915 }
1916 
1917 Klass* JavaThread::security_get_caller_class(int depth) {
1918   ResetNoHandleMark rnhm;
1919   HandleMark hm(Thread::current());
1920 
1921   vframeStream vfst(this);
1922   vfst.security_get_caller_frame(depth);
1923   if (!vfst.at_end()) {
1924     return vfst.method()->method_holder();
1925   }
1926   return NULL;
1927 }
1928 
1929 // java.lang.Thread.sleep support
1930 // Returns true if sleep time elapsed as expected, and false
1931 // if the thread was interrupted.
1932 bool JavaThread::sleep(jlong millis) {
1933   assert(this == Thread::current(),  "thread consistency check");
1934 
1935   ParkEvent * const slp = this->_SleepEvent;
1936   // Because there can be races with thread interruption sending an unpark()
1937   // to the event, we explicitly reset it here to avoid an immediate return.
1938   // The actual interrupt state will be checked before we park().
1939   slp->reset();
1940   // Thread interruption establishes a happens-before ordering in the
1941   // Java Memory Model, so we need to ensure we synchronize with the
1942   // interrupt state.
1943   OrderAccess::fence();
1944 
1945   jlong prevtime = os::javaTimeNanos();
1946 
1947   for (;;) {
1948     // interruption has precedence over timing out
1949     if (this->is_interrupted(true)) {
1950       return false;
1951     }
1952 
1953     if (millis <= 0) {
1954       return true;
1955     }
1956 
1957     {
1958       ThreadBlockInVM tbivm(this);
1959       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1960       slp->park(millis);
1961     }
1962 
1963     // Update elapsed time tracking
1964     jlong newtime = os::javaTimeNanos();
1965     if (newtime - prevtime < 0) {
1966       // time moving backwards, should only happen if no monotonic clock
1967       // not a guarantee() because JVM should not abort on kernel/glibc bugs
1968       assert(false,
1969              "unexpected time moving backwards detected in JavaThread::sleep()");
1970     } else {
1971       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
1972     }
1973     prevtime = newtime;
1974   }
1975 }
1976 
1977 // Last thread running calls java.lang.Shutdown.shutdown()
1978 void JavaThread::invoke_shutdown_hooks() {
1979   HandleMark hm(this);
1980 
1981   // We could get here with a pending exception, if so clear it now or
1982   // it will cause MetaspaceShared::link_shared_classes to
1983   // fail for dynamic dump.
1984   if (this->has_pending_exception()) {
1985     this->clear_pending_exception();
1986   }
1987 
1988 #if INCLUDE_CDS
1989   // Link all classes for dynamic CDS dumping before vm exit.
1990   // Same operation is being done in JVM_BeforeHalt for handling the
1991   // case where the application calls System.exit().
1992   if (DynamicArchive::should_dump_at_vm_exit()) {
1993     DynamicArchive::prepare_for_dump_at_exit();
1994   }
1995 #endif
1996 
1997   EXCEPTION_MARK;
1998   Klass* shutdown_klass =
1999     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2000                                       THREAD);
2001   if (shutdown_klass != NULL) {
2002     // SystemDictionary::resolve_or_null will return null if there was
2003     // an exception.  If we cannot load the Shutdown class, just don't
2004     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
2005     // won't be run.  Note that if a shutdown hook was registered,
2006     // the Shutdown class would have already been loaded
2007     // (Runtime.addShutdownHook will load it).
2008     JavaValue result(T_VOID);
2009     JavaCalls::call_static(&result,
2010                            shutdown_klass,
2011                            vmSymbols::shutdown_name(),
2012                            vmSymbols::void_method_signature(),
2013                            THREAD);
2014   }
2015   CLEAR_PENDING_EXCEPTION;
2016 }
2017 
2018 #ifndef PRODUCT
2019 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2020    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2021 }
2022 #endif
2023 
2024 // Helper function to create the java.lang.Thread object for a
2025 // VM-internal thread. The thread will have the given name, and be
2026 // a member of the "system" ThreadGroup.
2027 Handle JavaThread::create_system_thread_object(const char* name,
2028                                                bool is_visible, TRAPS) {
2029   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2030 
2031   // Initialize thread_oop to put it into the system threadGroup.
2032   // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2033   Handle thread_group(THREAD, Universe::system_thread_group());
2034   Handle thread_oop =
2035     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2036                                       vmSymbols::threadgroup_string_void_signature(),
2037                                       thread_group,
2038                                       string,
2039                                       CHECK_NH);
2040 
2041   return thread_oop;
2042 }
2043 
2044 // Starts the target JavaThread as a daemon of the given priority, and
2045 // bound to the given java.lang.Thread instance.
2046 // The Threads_lock is held for the duration.
2047 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2048                                        Handle thread_oop, ThreadPriority prio) {
2049 
2050   assert(target->osthread() != NULL, "target thread is not properly initialized");
2051 
2052   MutexLocker mu(current, Threads_lock);
2053 
2054   // Initialize the fields of the thread_oop first.
2055 
2056   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
2057 
2058   if (prio != NoPriority) {
2059     java_lang_Thread::set_priority(thread_oop(), prio);
2060     // Note: we don't call os::set_priority here. Possibly we should,
2061     // else all threads should call it themselves when they first run.
2062   }
2063 
2064   java_lang_Thread::set_daemon(thread_oop());
2065 
2066   // Now bind the thread_oop to the target JavaThread.
2067   target->set_threadOopHandles(thread_oop());
2068 
2069   Threads::add(target); // target is now visible for safepoint/handshake
2070   Thread::start(target);
2071 }
2072 
2073 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2074   // At this point it may be possible that no osthread was created for the
2075   // JavaThread due to lack of resources. However, since this must work
2076   // for critical system threads just check and abort if this fails.
2077   if (thread->osthread() == nullptr) {
2078     // This isn't really an OOM condition, but historically this is what
2079     // we report.
2080     vm_exit_during_initialization("java.lang.OutOfMemoryError",
2081                                   os::native_thread_creation_failed_msg());
2082   }
2083 }
2084 
2085 // Deferred OopHandle release support.
2086 
2087 class OopHandleList : public CHeapObj<mtInternal> {
2088   static const int _count = 4;
2089   OopHandle _handles[_count];
2090   OopHandleList* _next;
2091   int _index;
2092  public:
2093   OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2094   void add(OopHandle h) {
2095     assert(_index < _count, "too many additions");
2096     _handles[_index++] = h;
2097   }
2098   ~OopHandleList() {
2099     assert(_index == _count, "usage error");
2100     for (int i = 0; i < _index; i++) {
2101       _handles[i].release(JavaThread::thread_oop_storage());
2102     }
2103   }
2104   OopHandleList* next() const { return _next; }
2105 };
2106 
2107 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2108 
2109 // Called by the ServiceThread to do the work of releasing
2110 // the OopHandles.
2111 void JavaThread::release_oop_handles() {
2112   OopHandleList* list;
2113   {
2114     MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2115     list = _oop_handle_list;
2116     _oop_handle_list = nullptr;
2117   }
2118   assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2119 
2120   while (list != nullptr) {
2121     OopHandleList* l = list;
2122     list = l->next();
2123     delete l;
2124   }
2125 }
2126 
2127 // Add our OopHandles for later release.
2128 void JavaThread::add_oop_handles_for_release() {
2129   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2130   OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2131   new_head->add(_threadObj);
2132   new_head->add(_vthread);
2133   new_head->add(_jvmti_vthread);
2134   new_head->add(_extentLocalCache);
2135   _oop_handle_list = new_head;
2136   Service_lock->notify_all();
2137 }