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