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