1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "cds/dynamicArchive.hpp"
  28 #include "ci/ciEnv.hpp"
  29 #include "classfile/javaClasses.inline.hpp"
  30 #include "classfile/javaThreadStatus.hpp"
  31 #include "classfile/systemDictionary.hpp"
  32 #include "classfile/vmClasses.hpp"
  33 #include "classfile/vmSymbols.hpp"
  34 #include "code/codeCache.hpp"
  35 #include "code/scopeDesc.hpp"
  36 #include "compiler/compileTask.hpp"
  37 #include "compiler/compilerThread.hpp"
  38 #include "gc/shared/oopStorage.hpp"
  39 #include "gc/shared/oopStorageSet.hpp"
  40 #include "gc/shared/tlab_globals.hpp"
  41 #include "jfr/jfrEvents.hpp"
  42 #include "jvm.h"
  43 #include "jvmtifiles/jvmtiEnv.hpp"
  44 #include "logging/log.hpp"
  45 #include "logging/logAsyncWriter.hpp"
  46 #include "logging/logStream.hpp"
  47 #include "memory/allocation.inline.hpp"
  48 #include "memory/iterator.hpp"
  49 #include "memory/universe.hpp"
  50 #include "oops/access.inline.hpp"
  51 #include "oops/instanceKlass.hpp"
  52 #include "oops/klass.inline.hpp"
  53 #include "oops/oop.inline.hpp"
  54 #include "oops/oopHandle.inline.hpp"
  55 #include "oops/verifyOopClosure.hpp"
  56 #include "prims/jvm_misc.hpp"
  57 #include "prims/jvmtiDeferredUpdates.hpp"
  58 #include "prims/jvmtiExport.hpp"
  59 #include "prims/jvmtiThreadState.inline.hpp"
  60 #include "runtime/atomic.hpp"
  61 #include "runtime/continuation.hpp"
  62 #include "runtime/continuationEntry.inline.hpp"
  63 #include "runtime/continuationHelper.inline.hpp"
  64 #include "runtime/deoptimization.hpp"
  65 #include "runtime/frame.inline.hpp"
  66 #include "runtime/handles.inline.hpp"
  67 #include "runtime/handshake.hpp"
  68 #include "runtime/interfaceSupport.inline.hpp"
  69 #include "runtime/java.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/javaThread.inline.hpp"
  72 #include "runtime/jniHandles.inline.hpp"
  73 #include "runtime/mutexLocker.hpp"
  74 #include "runtime/orderAccess.hpp"
  75 #include "runtime/osThread.hpp"
  76 #include "runtime/safepoint.hpp"
  77 #include "runtime/safepointMechanism.inline.hpp"
  78 #include "runtime/safepointVerifiers.hpp"
  79 #include "runtime/serviceThread.hpp"
  80 #include "runtime/stackFrameStream.inline.hpp"
  81 #include "runtime/stackWatermarkSet.hpp"
  82 #include "runtime/synchronizer.hpp"
  83 #include "runtime/threadCritical.hpp"
  84 #include "runtime/threadSMR.inline.hpp"
  85 #include "runtime/threadStatisticalInfo.hpp"
  86 #include "runtime/threadWXSetters.inline.hpp"
  87 #include "runtime/timer.hpp"
  88 #include "runtime/timerTrace.hpp"
  89 #include "runtime/vframe.inline.hpp"
  90 #include "runtime/vframeArray.hpp"
  91 #include "runtime/vframe_hp.hpp"
  92 #include "runtime/vmThread.hpp"
  93 #include "runtime/vmOperations.hpp"
  94 #include "services/threadService.hpp"
  95 #include "utilities/copy.hpp"
  96 #include "utilities/defaultStream.hpp"
  97 #include "utilities/dtrace.hpp"
  98 #include "utilities/events.hpp"
  99 #include "utilities/macros.hpp"
 100 #include "utilities/preserveException.hpp"
 101 #include "utilities/spinYield.hpp"
 102 #if INCLUDE_JVMCI
 103 #include "jvmci/jvmci.hpp"
 104 #include "jvmci/jvmciEnv.hpp"
 105 #endif
 106 #if INCLUDE_JFR
 107 #include "jfr/jfr.hpp"
 108 #endif
 109 
 110 // Set by os layer.
 111 size_t      JavaThread::_stack_size_at_create = 0;
 112 
 113 #ifdef DTRACE_ENABLED
 114 
 115 // Only bother with this argument setup if dtrace is available
 116 
 117   #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
 118   #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
 119 
 120   #define DTRACE_THREAD_PROBE(probe, javathread)                           \
 121     {                                                                      \
 122       ResourceMark rm(this);                                               \
 123       int len = 0;                                                         \
 124       const char* name = (javathread)->name();                             \
 125       len = strlen(name);                                                  \
 126       HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
 127         (char *) name, len,                                                \
 128         java_lang_Thread::thread_id((javathread)->threadObj()),            \
 129         (uintptr_t) (javathread)->osthread()->thread_id(),                 \
 130         java_lang_Thread::is_daemon((javathread)->threadObj()));           \
 131     }
 132 
 133 #else //  ndef DTRACE_ENABLED
 134 
 135   #define DTRACE_THREAD_PROBE(probe, javathread)
 136 
 137 #endif // ndef DTRACE_ENABLED
 138 
 139 void JavaThread::smr_delete() {
 140   if (_on_thread_list) {
 141     ThreadsSMRSupport::smr_delete(this);
 142   } else {
 143     delete this;
 144   }
 145 }
 146 
 147 // Initialized by VMThread at vm_global_init
 148 OopStorage* JavaThread::_thread_oop_storage = NULL;
 149 
 150 OopStorage* JavaThread::thread_oop_storage() {
 151   assert(_thread_oop_storage != NULL, "not yet initialized");
 152   return _thread_oop_storage;
 153 }
 154 
 155 void JavaThread::set_threadOopHandles(oop p) {
 156   assert(_thread_oop_storage != NULL, "not yet initialized");
 157   _threadObj   = OopHandle(_thread_oop_storage, p);
 158   _vthread     = OopHandle(_thread_oop_storage, p);
 159   _jvmti_vthread = OopHandle(_thread_oop_storage, NULL);
 160   _scopedValueCache = 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::scopedValueCache() const {
 190   return _scopedValueCache.resolve();
 191 }
 192 
 193 void JavaThread::set_scopedValueCache(oop p) {
 194   if (_scopedValueCache.ptr_raw() != NULL) { // i.e. if the OopHandle has been allocated
 195     _scopedValueCache.replace(p);
 196   } else {
 197     assert(p == NULL, "not yet initialized");
 198   }
 199 }
 200 
 201 void JavaThread::clear_scopedValueBindings() {
 202   set_scopedValueCache(NULL);
 203   java_lang_Thread::clear_scopedValueBindings(vthread());
 204 }
 205 
 206 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
 207                                     bool daemon, TRAPS) {
 208   assert(thread_group.not_null(), "thread group should be specified");
 209   assert(threadObj() == NULL, "should only create Java thread object once");
 210 
 211   InstanceKlass* ik = vmClasses::Thread_klass();
 212   assert(ik->is_initialized(), "must be");
 213   instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 214 
 215   // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
 216   // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
 217   // constructor calls Thread.current(), which must be set here.
 218   java_lang_Thread::set_thread(thread_oop(), this);
 219   set_threadOopHandles(thread_oop());
 220 
 221   JavaValue result(T_VOID);
 222   if (thread_name != NULL) {
 223     Handle name = java_lang_String::create_from_str(thread_name, CHECK);
 224     // Thread gets assigned specified name and null target
 225     JavaCalls::call_special(&result,
 226                             thread_oop,
 227                             ik,
 228                             vmSymbols::object_initializer_name(),
 229                             vmSymbols::threadgroup_string_void_signature(),
 230                             thread_group,
 231                             name,
 232                             THREAD);
 233   } else {
 234     // Thread gets assigned name "Thread-nnn" and null target
 235     // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
 236     JavaCalls::call_special(&result,
 237                             thread_oop,
 238                             ik,
 239                             vmSymbols::object_initializer_name(),
 240                             vmSymbols::threadgroup_runnable_void_signature(),
 241                             thread_group,
 242                             Handle(),
 243                             THREAD);
 244   }
 245   os::set_priority(this, NormPriority);
 246 
 247   if (daemon) {
 248     java_lang_Thread::set_daemon(thread_oop());
 249   }
 250 }
 251 
 252 // ======= JavaThread ========
 253 
 254 #if INCLUDE_JVMCI
 255 
 256 jlong* JavaThread::_jvmci_old_thread_counters;
 257 
 258 bool jvmci_counters_include(JavaThread* thread) {
 259   return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
 260 }
 261 
 262 void JavaThread::collect_counters(jlong* array, int length) {
 263   assert(length == JVMCICounterSize, "wrong value");
 264   for (int i = 0; i < length; i++) {
 265     array[i] = _jvmci_old_thread_counters[i];
 266   }
 267   for (JavaThread* tp : ThreadsListHandle()) {
 268     if (jvmci_counters_include(tp)) {
 269       for (int i = 0; i < length; i++) {
 270         array[i] += tp->_jvmci_counters[i];
 271       }
 272     }
 273   }
 274 }
 275 
 276 // Attempt to enlarge the array for per thread counters.
 277 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
 278   jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
 279   if (new_counters == NULL) {
 280     return NULL;
 281   }
 282   if (old_counters == NULL) {
 283     old_counters = new_counters;
 284     memset(old_counters, 0, sizeof(jlong) * new_size);
 285   } else {
 286     for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
 287       new_counters[i] = old_counters[i];
 288     }
 289     if (new_size > current_size) {
 290       memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
 291     }
 292     FREE_C_HEAP_ARRAY(jlong, old_counters);
 293   }
 294   return new_counters;
 295 }
 296 
 297 // Attempt to enlarge the array for per thread counters.
 298 bool JavaThread::resize_counters(int current_size, int new_size) {
 299   jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
 300   if (new_counters == NULL) {
 301     return false;
 302   } else {
 303     _jvmci_counters = new_counters;
 304     return true;
 305   }
 306 }
 307 
 308 class VM_JVMCIResizeCounters : public VM_Operation {
 309  private:
 310   int _new_size;
 311   bool _failed;
 312 
 313  public:
 314   VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
 315   VMOp_Type type()                  const        { return VMOp_JVMCIResizeCounters; }
 316   bool allow_nested_vm_operations() const        { return true; }
 317   void doit() {
 318     // Resize the old thread counters array
 319     jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
 320     if (new_counters == NULL) {
 321       _failed = true;
 322       return;
 323     } else {
 324       JavaThread::_jvmci_old_thread_counters = new_counters;
 325     }
 326 
 327     // Now resize each threads array
 328     for (JavaThread* tp : ThreadsListHandle()) {
 329       if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
 330         _failed = true;
 331         break;
 332       }
 333     }
 334     if (!_failed) {
 335       JVMCICounterSize = _new_size;
 336     }
 337   }
 338 
 339   bool failed() { return _failed; }
 340 };
 341 
 342 bool JavaThread::resize_all_jvmci_counters(int new_size) {
 343   VM_JVMCIResizeCounters op(new_size);
 344   VMThread::execute(&op);
 345   return !op.failed();
 346 }
 347 
 348 #endif // INCLUDE_JVMCI
 349 
 350 #ifdef ASSERT
 351 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
 352 void JavaThread::check_possible_safepoint() {
 353   if (_no_safepoint_count > 0) {
 354     print_owned_locks();
 355     assert(false, "Possible safepoint reached by thread that does not allow it");
 356   }
 357 #ifdef CHECK_UNHANDLED_OOPS
 358   // Clear unhandled oops in JavaThreads so we get a crash right away.
 359   clear_unhandled_oops();
 360 #endif // CHECK_UNHANDLED_OOPS
 361 
 362   // Macos/aarch64 should be in the right state for safepoint (e.g.
 363   // deoptimization needs WXWrite).  Crashes caused by the wrong state rarely
 364   // happens in practice, making such issues hard to find and reproduce.
 365 #if defined(__APPLE__) && defined(AARCH64)
 366   if (AssertWXAtThreadSync) {
 367     assert_wx_state(WXWrite);
 368   }
 369 #endif
 370 }
 371 
 372 void JavaThread::check_for_valid_safepoint_state() {
 373   // Check NoSafepointVerifier, which is implied by locks taken that can be
 374   // shared with the VM thread.  This makes sure that no locks with allow_vm_block
 375   // are held.
 376   check_possible_safepoint();
 377 
 378   if (thread_state() != _thread_in_vm) {
 379     fatal("LEAF method calling lock?");
 380   }
 381 
 382   if (GCALotAtAllSafepoints) {
 383     // We could enter a safepoint here and thus have a gc
 384     InterfaceSupport::check_gc_alot();
 385   }
 386 }
 387 #endif // ASSERT
 388 
 389 // A JavaThread is a normal Java thread
 390 
 391 JavaThread::JavaThread() :
 392   // Initialize fields
 393 
 394   _in_asgct(false),
 395   _on_thread_list(false),
 396   DEBUG_ONLY(_java_call_counter(0) COMMA)
 397   _entry_point(nullptr),
 398   _deopt_mark(nullptr),
 399   _deopt_nmethod(nullptr),
 400   _vframe_array_head(nullptr),
 401   _vframe_array_last(nullptr),
 402   _jvmti_deferred_updates(nullptr),
 403   _callee_target(nullptr),
 404   _vm_result(nullptr),
 405   _vm_result_2(nullptr),
 406 
 407   _current_pending_monitor(NULL),
 408   _current_pending_monitor_is_from_java(true),
 409   _current_waiting_monitor(NULL),
 410   _active_handles(NULL),
 411   _free_handle_block(NULL),
 412   _Stalled(0),
 413 
 414   _monitor_chunks(nullptr),
 415 
 416   _suspend_flags(0),
 417 
 418   _thread_state(_thread_new),
 419   _saved_exception_pc(nullptr),
 420 #ifdef ASSERT
 421   _no_safepoint_count(0),
 422   _visited_for_critical_count(false),
 423 #endif
 424 
 425   _terminated(_not_terminated),
 426   _in_deopt_handler(0),
 427   _doing_unsafe_access(false),
 428   _do_not_unlock_if_synchronized(false),
 429 #if INCLUDE_JVMTI
 430   _carrier_thread_suspended(false),
 431   _is_in_VTMS_transition(false),
 432   _is_in_tmp_VTMS_transition(false),
 433 #ifdef ASSERT
 434   _is_VTMS_transition_disabler(false),
 435 #endif
 436 #endif
 437   _jni_attach_state(_not_attaching_via_jni),
 438 #if INCLUDE_JVMCI
 439   _pending_deoptimization(-1),
 440   _pending_monitorenter(false),
 441   _pending_transfer_to_interpreter(false),
 442   _in_retryable_allocation(false),
 443   _pending_failed_speculation(0),
 444   _jvmci{nullptr},
 445   _libjvmci_runtime(nullptr),
 446   _jvmci_counters(nullptr),
 447   _jvmci_reserved0(0),
 448   _jvmci_reserved1(0),
 449   _jvmci_reserved_oop0(nullptr),
 450 #endif // INCLUDE_JVMCI
 451 
 452   _exception_oop(oop()),
 453   _exception_pc(0),
 454   _exception_handler_pc(0),
 455   _is_method_handle_return(0),
 456 
 457   _jni_active_critical(0),
 458   _pending_jni_exception_check_fn(nullptr),
 459   _depth_first_number(0),
 460 
 461   // JVMTI PopFrame support
 462   _popframe_condition(popframe_inactive),
 463   _frames_to_pop_failed_realloc(0),
 464 
 465   _cont_entry(nullptr),
 466   _cont_fastpath(0),
 467   _cont_fastpath_thread_state(1),
 468   _held_monitor_count(0),
 469   _jni_monitor_count(0),
 470 
 471   _handshake(this),
 472 
 473   _popframe_preserved_args(nullptr),
 474   _popframe_preserved_args_size(0),
 475 
 476   _jvmti_thread_state(nullptr),
 477   _interp_only_mode(0),
 478   _should_post_on_exceptions_flag(JNI_FALSE),
 479   _thread_stat(new ThreadStatistics()),
 480 
 481   _parker(),
 482 
 483   _class_to_be_initialized(nullptr),
 484 
 485   _SleepEvent(ParkEvent::Allocate(this))
 486 {
 487   set_jni_functions(jni_functions());
 488 
 489 #if INCLUDE_JVMCI
 490   assert(_jvmci._implicit_exception_pc == nullptr, "must be");
 491   if (JVMCICounterSize > 0) {
 492     resize_counters(0, (int) JVMCICounterSize);
 493   }
 494 #endif // INCLUDE_JVMCI
 495 
 496   // Setup safepoint state info for this thread
 497   ThreadSafepointState::create(this);
 498 
 499   SafepointMechanism::initialize_header(this);
 500 
 501   set_requires_cross_modify_fence(false);
 502 
 503   pd_initialize();
 504   assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
 505 }
 506 
 507 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
 508   if (is_attaching_via_jni) {
 509     _jni_attach_state = _attaching_via_jni;
 510   }
 511 }
 512 
 513 
 514 // interrupt support
 515 
 516 void JavaThread::interrupt() {
 517   // All callers should have 'this' thread protected by a
 518   // ThreadsListHandle so that it cannot terminate and deallocate
 519   // itself.
 520   debug_only(check_for_dangling_thread_pointer(this);)
 521 
 522   // For Windows _interrupt_event
 523   WINDOWS_ONLY(osthread()->set_interrupted(true);)
 524 
 525   // For Thread.sleep
 526   _SleepEvent->unpark();
 527 
 528   // For JSR166 LockSupport.park
 529   parker()->unpark();
 530 
 531   // For ObjectMonitor and JvmtiRawMonitor
 532   _ParkEvent->unpark();
 533 }
 534 
 535 
 536 bool JavaThread::is_interrupted(bool clear_interrupted) {
 537   debug_only(check_for_dangling_thread_pointer(this);)
 538 
 539   if (_threadObj.peek() == NULL) {
 540     // If there is no j.l.Thread then it is impossible to have
 541     // been interrupted. We can find NULL during VM initialization
 542     // or when a JNI thread is still in the process of attaching.
 543     // In such cases this must be the current thread.
 544     assert(this == Thread::current(), "invariant");
 545     return false;
 546   }
 547 
 548   bool interrupted = java_lang_Thread::interrupted(threadObj());
 549 
 550   // NOTE that since there is no "lock" around the interrupt and
 551   // is_interrupted operations, there is the possibility that the
 552   // interrupted flag will be "false" but that the
 553   // low-level events will be in the signaled state. This is
 554   // intentional. The effect of this is that Object.wait() and
 555   // LockSupport.park() will appear to have a spurious wakeup, which
 556   // is allowed and not harmful, and the possibility is so rare that
 557   // it is not worth the added complexity to add yet another lock.
 558   // For the sleep event an explicit reset is performed on entry
 559   // to JavaThread::sleep, so there is no early return. It has also been
 560   // recommended not to put the interrupted flag into the "event"
 561   // structure because it hides the issue.
 562   // Also, because there is no lock, we must only clear the interrupt
 563   // state if we are going to report that we were interrupted; otherwise
 564   // an interrupt that happens just after we read the field would be lost.
 565   if (interrupted && clear_interrupted) {
 566     assert(this == Thread::current(), "only the current thread can clear");
 567     java_lang_Thread::set_interrupted(threadObj(), false);
 568     WINDOWS_ONLY(osthread()->set_interrupted(false);)
 569   }
 570 
 571   return interrupted;
 572 }
 573 
 574 void JavaThread::block_if_vm_exited() {
 575   if (_terminated == _vm_exited) {
 576     // _vm_exited is set at safepoint, and Threads_lock is never released
 577     // so we will block here forever.
 578     // Here we can be doing a jump from a safe state to an unsafe state without
 579     // proper transition, but it happens after the final safepoint has begun so
 580     // this jump won't cause any safepoint problems.
 581     set_thread_state(_thread_in_vm);
 582     Threads_lock->lock();
 583     ShouldNotReachHere();
 584   }
 585 }
 586 
 587 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
 588   _jni_attach_state = _not_attaching_via_jni;
 589   set_entry_point(entry_point);
 590   // Create the native thread itself.
 591   // %note runtime_23
 592   os::ThreadType thr_type = os::java_thread;
 593   thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
 594                                                             os::java_thread;
 595   os::create_thread(this, thr_type, stack_sz);
 596   // The _osthread may be NULL here because we ran out of memory (too many threads active).
 597   // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
 598   // may hold a lock and all locks must be unlocked before throwing the exception (throwing
 599   // the exception consists of creating the exception object & initializing it, initialization
 600   // will leave the VM via a JavaCall and then all locks must be unlocked).
 601   //
 602   // The thread is still suspended when we reach here. Thread must be explicit started
 603   // by creator! Furthermore, the thread must also explicitly be added to the Threads list
 604   // by calling Threads:add. The reason why this is not done here, is because the thread
 605   // object must be fully initialized (take a look at JVM_Start)
 606 }
 607 
 608 JavaThread::~JavaThread() {
 609 
 610   // Enqueue OopHandles for release by the service thread.
 611   add_oop_handles_for_release();
 612 
 613   // Return the sleep event to the free list
 614   ParkEvent::Release(_SleepEvent);
 615   _SleepEvent = NULL;
 616 
 617   // Free any remaining  previous UnrollBlock
 618   vframeArray* old_array = vframe_array_last();
 619 
 620   if (old_array != NULL) {
 621     Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
 622     old_array->set_unroll_block(NULL);
 623     delete old_info;
 624     delete old_array;
 625   }
 626 
 627   JvmtiDeferredUpdates* updates = deferred_updates();
 628   if (updates != NULL) {
 629     // This can only happen if thread is destroyed before deoptimization occurs.
 630     assert(updates->count() > 0, "Updates holder not deleted");
 631     // free deferred updates.
 632     delete updates;
 633     set_deferred_updates(NULL);
 634   }
 635 
 636   // All Java related clean up happens in exit
 637   ThreadSafepointState::destroy(this);
 638   if (_thread_stat != NULL) delete _thread_stat;
 639 
 640 #if INCLUDE_JVMCI
 641   if (JVMCICounterSize > 0) {
 642     FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
 643   }
 644 #endif // INCLUDE_JVMCI
 645 }
 646 
 647 
 648 // First JavaThread specific code executed by a new Java thread.
 649 void JavaThread::pre_run() {
 650   // empty - see comments in run()
 651 }
 652 
 653 // The main routine called by a new Java thread. This isn't overridden
 654 // by subclasses, instead different subclasses define a different "entry_point"
 655 // which defines the actual logic for that kind of thread.
 656 void JavaThread::run() {
 657   // initialize thread-local alloc buffer related fields
 658   initialize_tlab();
 659 
 660   _stack_overflow_state.create_stack_guard_pages();
 661 
 662   cache_global_variables();
 663 
 664   // Thread is now sufficiently initialized to be handled by the safepoint code as being
 665   // in the VM. Change thread state from _thread_new to _thread_in_vm
 666   assert(this->thread_state() == _thread_new, "wrong thread state");
 667   set_thread_state(_thread_in_vm);
 668 
 669   // Before a thread is on the threads list it is always safe, so after leaving the
 670   // _thread_new we should emit a instruction barrier. The distance to modified code
 671   // from here is probably far enough, but this is consistent and safe.
 672   OrderAccess::cross_modify_fence();
 673 
 674   assert(JavaThread::current() == this, "sanity check");
 675   assert(!Thread::current()->owns_locks(), "sanity check");
 676 
 677   DTRACE_THREAD_PROBE(start, this);
 678 
 679   // This operation might block. We call that after all safepoint checks for a new thread has
 680   // been completed.
 681   set_active_handles(JNIHandleBlock::allocate_block());
 682 
 683   if (JvmtiExport::should_post_thread_life()) {
 684     JvmtiExport::post_thread_start(this);
 685 
 686   }
 687 
 688   // We call another function to do the rest so we are sure that the stack addresses used
 689   // from there will be lower than the stack base just computed.
 690   thread_main_inner();
 691 }
 692 
 693 void JavaThread::thread_main_inner() {
 694   assert(JavaThread::current() == this, "sanity check");
 695   assert(_threadObj.peek() != NULL, "just checking");
 696 
 697   // Execute thread entry point unless this thread has a pending exception.
 698   // Note: Due to JVMTI StopThread we can have pending exceptions already!
 699   if (!this->has_pending_exception()) {
 700     {
 701       ResourceMark rm(this);
 702       this->set_native_thread_name(this->name());
 703     }
 704     HandleMark hm(this);
 705     this->entry_point()(this, this);
 706   }
 707 
 708   DTRACE_THREAD_PROBE(stop, this);
 709 
 710   // Cleanup is handled in post_run()
 711 }
 712 
 713 // Shared teardown for all JavaThreads
 714 void JavaThread::post_run() {
 715   this->exit(false);
 716   this->unregister_thread_stack_with_NMT();
 717   // Defer deletion to here to ensure 'this' is still referenceable in call_run
 718   // for any shared tear-down.
 719   this->smr_delete();
 720 }
 721 
 722 static void ensure_join(JavaThread* thread) {
 723   // We do not need to grab the Threads_lock, since we are operating on ourself.
 724   Handle threadObj(thread, thread->threadObj());
 725   assert(threadObj.not_null(), "java thread object must exist");
 726   ObjectLocker lock(threadObj, thread);
 727   // Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
 728   java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
 729   // Clear the native thread instance - this makes isAlive return false and allows the join()
 730   // to complete once we've done the notify_all below
 731   java_lang_Thread::set_thread(threadObj(), NULL);
 732   lock.notify_all(thread);
 733   // Ignore pending exception, since we are exiting anyway
 734   thread->clear_pending_exception();
 735 }
 736 
 737 static bool is_daemon(oop threadObj) {
 738   return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj));
 739 }
 740 
 741 // For any new cleanup additions, please check to see if they need to be applied to
 742 // cleanup_failed_attach_current_thread as well.
 743 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
 744   assert(this == JavaThread::current(), "thread consistency check");
 745   assert(!is_exiting(), "should not be exiting or terminated already");
 746 
 747   elapsedTimer _timer_exit_phase1;
 748   elapsedTimer _timer_exit_phase2;
 749   elapsedTimer _timer_exit_phase3;
 750   elapsedTimer _timer_exit_phase4;
 751 
 752   if (log_is_enabled(Debug, os, thread, timer)) {
 753     _timer_exit_phase1.start();
 754   }
 755 
 756   HandleMark hm(this);
 757   Handle uncaught_exception(this, this->pending_exception());
 758   this->clear_pending_exception();
 759   Handle threadObj(this, this->threadObj());
 760   assert(threadObj.not_null(), "Java thread object should be created");
 761 
 762   if (!destroy_vm) {
 763     if (uncaught_exception.not_null()) {
 764       EXCEPTION_MARK;
 765       // Call method Thread.dispatchUncaughtException().
 766       Klass* thread_klass = vmClasses::Thread_klass();
 767       JavaValue result(T_VOID);
 768       JavaCalls::call_virtual(&result,
 769                               threadObj, thread_klass,
 770                               vmSymbols::dispatchUncaughtException_name(),
 771                               vmSymbols::throwable_void_signature(),
 772                               uncaught_exception,
 773                               THREAD);
 774       if (HAS_PENDING_EXCEPTION) {
 775         ResourceMark rm(this);
 776         jio_fprintf(defaultStream::error_stream(),
 777                     "\nException: %s thrown from the UncaughtExceptionHandler"
 778                     " in thread \"%s\"\n",
 779                     pending_exception()->klass()->external_name(),
 780                     name());
 781         CLEAR_PENDING_EXCEPTION;
 782       }
 783     }
 784 
 785     if (!is_Compiler_thread()) {
 786       // We have finished executing user-defined Java code and now have to do the
 787       // implementation specific clean-up by calling Thread.exit(). We prevent any
 788       // asynchronous exceptions from being delivered while in Thread.exit()
 789       // to ensure the clean-up is not corrupted.
 790       NoAsyncExceptionDeliveryMark _no_async(this);
 791 
 792       EXCEPTION_MARK;
 793       JavaValue result(T_VOID);
 794       Klass* thread_klass = vmClasses::Thread_klass();
 795       JavaCalls::call_virtual(&result,
 796                               threadObj, thread_klass,
 797                               vmSymbols::exit_method_name(),
 798                               vmSymbols::void_method_signature(),
 799                               THREAD);
 800       CLEAR_PENDING_EXCEPTION;
 801     }
 802 
 803     // notify JVMTI
 804     if (JvmtiExport::should_post_thread_life()) {
 805       JvmtiExport::post_thread_end(this);
 806     }
 807   } else {
 808     // before_exit() has already posted JVMTI THREAD_END events
 809   }
 810 
 811   // Cleanup any pending async exception now since we cannot access oops after
 812   // BarrierSet::barrier_set()->on_thread_detach() has been executed.
 813   if (has_async_exception_condition()) {
 814     handshake_state()->clean_async_exception_operation();
 815   }
 816 
 817   // The careful dance between thread suspension and exit is handled here.
 818   // Since we are in thread_in_vm state and suspension is done with handshakes,
 819   // we can just put in the exiting state and it will be correctly handled.
 820   // Also, no more async exceptions will be added to the queue after this point.
 821   set_terminated(_thread_exiting);
 822   ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
 823 
 824   if (log_is_enabled(Debug, os, thread, timer)) {
 825     _timer_exit_phase1.stop();
 826     _timer_exit_phase2.start();
 827   }
 828 
 829   // Capture daemon status before the thread is marked as terminated.
 830   bool daemon = is_daemon(threadObj());
 831 
 832   // Notify waiters on thread object. This has to be done after exit() is called
 833   // on the thread (if the thread is the last thread in a daemon ThreadGroup the
 834   // group should have the destroyed bit set before waiters are notified).
 835   ensure_join(this);
 836   assert(!this->has_pending_exception(), "ensure_join should have cleared");
 837 
 838   if (log_is_enabled(Debug, os, thread, timer)) {
 839     _timer_exit_phase2.stop();
 840     _timer_exit_phase3.start();
 841   }
 842   // 6282335 JNI DetachCurrentThread spec states that all Java monitors
 843   // held by this thread must be released. The spec does not distinguish
 844   // between JNI-acquired and regular Java monitors. We can only see
 845   // regular Java monitors here if monitor enter-exit matching is broken.
 846   //
 847   // ensure_join() ignores IllegalThreadStateExceptions, and so does
 848   // ObjectSynchronizer::release_monitors_owned_by_thread().
 849   if (exit_type == jni_detach) {
 850     // Sanity check even though JNI DetachCurrentThread() would have
 851     // returned JNI_ERR if there was a Java frame. JavaThread exit
 852     // should be done executing Java code by the time we get here.
 853     assert(!this->has_last_Java_frame(),
 854            "should not have a Java frame when detaching or exiting");
 855     ObjectSynchronizer::release_monitors_owned_by_thread(this);
 856     assert(!this->has_pending_exception(), "release_monitors should have cleared");
 857   }
 858 
 859   // Since above code may not release JNI monitors and if someone forgot to do an
 860   // JNI monitorexit, held count should be equal jni count.
 861   // Consider scan all object monitor for this owner if JNI count > 0 (at least on detach).
 862   assert(this->held_monitor_count() == this->jni_monitor_count(),
 863          "held monitor count should be equal to jni: " INT64_FORMAT " != " INT64_FORMAT,
 864          (int64_t)this->held_monitor_count(), (int64_t)this->jni_monitor_count());
 865   if (CheckJNICalls && this->jni_monitor_count() > 0) {
 866     // We would like a fatal here, but due to we never checked this before there
 867     // is a lot of tests which breaks, even with an error log.
 868     log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
 869       exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
 870   }
 871 
 872   // These things needs to be done while we are still a Java Thread. Make sure that thread
 873   // is in a consistent state, in case GC happens
 874   JFR_ONLY(Jfr::on_thread_exit(this);)
 875 
 876   if (active_handles() != NULL) {
 877     JNIHandleBlock* block = active_handles();
 878     set_active_handles(NULL);
 879     JNIHandleBlock::release_block(block);
 880   }
 881 
 882   if (free_handle_block() != NULL) {
 883     JNIHandleBlock* block = free_handle_block();
 884     set_free_handle_block(NULL);
 885     JNIHandleBlock::release_block(block);
 886   }
 887 
 888   // These have to be removed while this is still a valid thread.
 889   _stack_overflow_state.remove_stack_guard_pages();
 890 
 891   if (UseTLAB) {
 892     tlab().retire();
 893   }
 894 
 895   if (JvmtiEnv::environments_might_exist()) {
 896     JvmtiExport::cleanup_thread(this);
 897   }
 898 
 899   // We need to cache the thread name for logging purposes below as once
 900   // we have called on_thread_detach this thread must not access any oops.
 901   char* thread_name = NULL;
 902   if (log_is_enabled(Debug, os, thread, timer)) {
 903     ResourceMark rm(this);
 904     thread_name = os::strdup(name());
 905   }
 906 
 907   log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
 908     exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
 909     os::current_thread_id());
 910 
 911   if (log_is_enabled(Debug, os, thread, timer)) {
 912     _timer_exit_phase3.stop();
 913     _timer_exit_phase4.start();
 914   }
 915 
 916 #if INCLUDE_JVMCI
 917   if (JVMCICounterSize > 0) {
 918     if (jvmci_counters_include(this)) {
 919       for (int i = 0; i < JVMCICounterSize; i++) {
 920         _jvmci_old_thread_counters[i] += _jvmci_counters[i];
 921       }
 922     }
 923   }
 924 #endif // INCLUDE_JVMCI
 925 
 926   // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
 927   // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
 928   Threads::remove(this, daemon);
 929 
 930   if (log_is_enabled(Debug, os, thread, timer)) {
 931     _timer_exit_phase4.stop();
 932     log_debug(os, thread, timer)("name='%s'"
 933                                  ", exit-phase1=" JLONG_FORMAT
 934                                  ", exit-phase2=" JLONG_FORMAT
 935                                  ", exit-phase3=" JLONG_FORMAT
 936                                  ", exit-phase4=" JLONG_FORMAT,
 937                                  thread_name,
 938                                  _timer_exit_phase1.milliseconds(),
 939                                  _timer_exit_phase2.milliseconds(),
 940                                  _timer_exit_phase3.milliseconds(),
 941                                  _timer_exit_phase4.milliseconds());
 942     os::free(thread_name);
 943   }
 944 }
 945 
 946 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
 947   if (active_handles() != NULL) {
 948     JNIHandleBlock* block = active_handles();
 949     set_active_handles(NULL);
 950     JNIHandleBlock::release_block(block);
 951   }
 952 
 953   if (free_handle_block() != NULL) {
 954     JNIHandleBlock* block = free_handle_block();
 955     set_free_handle_block(NULL);
 956     JNIHandleBlock::release_block(block);
 957   }
 958 
 959   // These have to be removed while this is still a valid thread.
 960   _stack_overflow_state.remove_stack_guard_pages();
 961 
 962   if (UseTLAB) {
 963     tlab().retire();
 964   }
 965 
 966   Threads::remove(this, is_daemon);
 967   this->smr_delete();
 968 }
 969 
 970 JavaThread* JavaThread::active() {
 971   Thread* thread = Thread::current();
 972   if (thread->is_Java_thread()) {
 973     return JavaThread::cast(thread);
 974   } else {
 975     assert(thread->is_VM_thread(), "this must be a vm thread");
 976     VM_Operation* op = ((VMThread*) thread)->vm_operation();
 977     JavaThread *ret = op == NULL ? NULL : JavaThread::cast(op->calling_thread());
 978     return ret;
 979   }
 980 }
 981 
 982 bool JavaThread::is_lock_owned(address adr) const {
 983   if (Thread::is_lock_owned(adr)) return true;
 984 
 985   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
 986     if (chunk->contains(adr)) return true;
 987   }
 988 
 989   return false;
 990 }
 991 
 992 bool JavaThread::is_lock_owned_current(address adr) const {
 993   address stack_end = _stack_base - _stack_size;
 994   const ContinuationEntry* ce = vthread_continuation();
 995   address stack_base = ce != nullptr ? (address)ce->entry_sp() : _stack_base;
 996   if (stack_base > adr && adr >= stack_end) {
 997     return true;
 998   }
 999 
1000   for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1001     if (chunk->contains(adr)) {
1002       return true;
1003     }
1004   }
1005 
1006   return false;
1007 }
1008 
1009 bool JavaThread::is_lock_owned_carrier(address adr) const {
1010   assert(is_vthread_mounted(), "");
1011   address stack_end = _stack_base - _stack_size;
1012   address stack_base = (address)vthread_continuation()->entry_sp();
1013   return stack_base > adr && adr >= stack_end;
1014 }
1015 
1016 oop JavaThread::exception_oop() const {
1017   return Atomic::load(&_exception_oop);
1018 }
1019 
1020 void JavaThread::set_exception_oop(oop o) {
1021   Atomic::store(&_exception_oop, o);
1022 }
1023 
1024 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1025   chunk->set_next(monitor_chunks());
1026   set_monitor_chunks(chunk);
1027 }
1028 
1029 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1030   guarantee(monitor_chunks() != NULL, "must be non empty");
1031   if (monitor_chunks() == chunk) {
1032     set_monitor_chunks(chunk->next());
1033   } else {
1034     MonitorChunk* prev = monitor_chunks();
1035     while (prev->next() != chunk) prev = prev->next();
1036     prev->set_next(chunk->next());
1037   }
1038 }
1039 
1040 void JavaThread::handle_special_runtime_exit_condition() {
1041   if (is_obj_deopt_suspend()) {
1042     frame_anchor()->make_walkable();
1043     wait_for_object_deoptimization();
1044   }
1045   JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1046 }
1047 
1048 
1049 // Asynchronous exceptions support
1050 //
1051 void JavaThread::handle_async_exception(oop java_throwable) {
1052   assert(java_throwable != NULL, "should have an _async_exception to throw");
1053   assert(!is_at_poll_safepoint(), "should have never called this method");
1054 
1055   if (has_last_Java_frame()) {
1056     frame f = last_frame();
1057     if (f.is_runtime_frame()) {
1058       // If the topmost frame is a runtime stub, then we are calling into
1059       // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1060       // must deoptimize the caller before continuing, as the compiled exception
1061       // handler table may not be valid.
1062       RegisterMap reg_map(this,
1063                           RegisterMap::UpdateMap::skip,
1064                           RegisterMap::ProcessFrames::include,
1065                           RegisterMap::WalkContinuation::skip);
1066       frame compiled_frame = f.sender(&reg_map);
1067       if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1068         Deoptimization::deoptimize(this, compiled_frame);
1069       }
1070     }
1071   }
1072 
1073   // We cannot call Exceptions::_throw(...) here because we cannot block
1074   set_pending_exception(java_throwable, __FILE__, __LINE__);
1075 
1076   clear_scopedValueBindings();
1077 
1078   LogTarget(Info, exceptions) lt;
1079   if (lt.is_enabled()) {
1080     ResourceMark rm;
1081     LogStream ls(lt);
1082     ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1083     if (has_last_Java_frame()) {
1084       frame f = last_frame();
1085       ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1086     }
1087     ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1088   }
1089 }
1090 
1091 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1092   // Do not throw asynchronous exceptions against the compiler thread
1093   // or if the thread is already exiting.
1094   if (!can_call_java() || is_exiting()) {
1095     delete aeh;
1096     return;
1097   }
1098 
1099   oop exception = aeh->exception();
1100   Handshake::execute(aeh, this);  // Install asynchronous handshake
1101 
1102   ResourceMark rm;
1103   if (log_is_enabled(Info, exceptions)) {
1104     log_info(exceptions)("Pending Async. exception installed of type: %s",
1105                          InstanceKlass::cast(exception->klass())->external_name());
1106   }
1107   // for AbortVMOnException flag
1108   Exceptions::debug_check_abort(exception->klass()->external_name());
1109 
1110   // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1111   java_lang_Thread::set_interrupted(threadObj(), true);
1112   this->interrupt();
1113 }
1114 
1115 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1116   AsyncExceptionHandshake* _aeh;
1117 public:
1118   InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1119     HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1120   ~InstallAsyncExceptionHandshake() {
1121     // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1122     delete _aeh;
1123   }
1124   void do_thread(Thread* thr) {
1125     JavaThread* target = JavaThread::cast(thr);
1126     target->install_async_exception(_aeh);
1127     _aeh = nullptr;
1128   }
1129 };
1130 
1131 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1132   OopHandle e(Universe::vm_global(), java_throwable);
1133   InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1134   Handshake::execute(&iaeh, target);
1135 }
1136 
1137 #if INCLUDE_JVMTI
1138 void JavaThread::set_is_in_VTMS_transition(bool val) {
1139   _is_in_VTMS_transition = val;
1140 }
1141 
1142 #ifdef ASSERT
1143 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1144   _is_VTMS_transition_disabler = val;
1145 }
1146 #endif
1147 #endif
1148 
1149 // External suspension mechanism.
1150 //
1151 // Guarantees on return (for a valid target thread):
1152 //   - Target thread will not execute any new bytecode.
1153 //   - Target thread will not enter any new monitors.
1154 //
1155 bool JavaThread::java_suspend() {
1156 #if INCLUDE_JVMTI
1157   // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1158   assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1159   assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1160 #endif
1161 
1162   guarantee(Thread::is_JavaThread_protected(/* target */ this),
1163             "target JavaThread is not protected in calling context.");
1164   return this->handshake_state()->suspend();
1165 }
1166 
1167 bool JavaThread::java_resume() {
1168   guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1169             "missing ThreadsListHandle in calling context.");
1170   return this->handshake_state()->resume();
1171 }
1172 
1173 // Wait for another thread to perform object reallocation and relocking on behalf of
1174 // this thread. The current thread is required to change to _thread_blocked in order
1175 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1176 // handshake safe, the other thread can complete the handshake used to synchronize
1177 // with this thread and then perform the reallocation and relocking.
1178 // See EscapeBarrier::sync_and_suspend_*()
1179 
1180 void JavaThread::wait_for_object_deoptimization() {
1181   assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1182   assert(this == Thread::current(), "invariant");
1183 
1184   bool spin_wait = os::is_MP();
1185   do {
1186     ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1187     // Wait for object deoptimization if requested.
1188     if (spin_wait) {
1189       // A single deoptimization is typically very short. Microbenchmarks
1190       // showed 5% better performance when spinning.
1191       const uint spin_limit = 10 * SpinYield::default_spin_limit;
1192       SpinYield spin(spin_limit);
1193       for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1194         spin.wait();
1195       }
1196       // Spin just once
1197       spin_wait = false;
1198     } else {
1199       MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1200       if (is_obj_deopt_suspend()) {
1201         ml.wait();
1202       }
1203     }
1204     // A handshake for obj. deoptimization suspend could have been processed so
1205     // we must check after processing.
1206   } while (is_obj_deopt_suspend());
1207 }
1208 
1209 #ifdef ASSERT
1210 // Verify the JavaThread has not yet been published in the Threads::list, and
1211 // hence doesn't need protection from concurrent access at this stage.
1212 void JavaThread::verify_not_published() {
1213   // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1214   // since an unpublished JavaThread doesn't participate in the
1215   // Thread-SMR protocol for keeping a ThreadsList alive.
1216   assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1217 }
1218 #endif
1219 
1220 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1221 // pending, when _suspend_flags is non-zero or when we need to process a stack
1222 // watermark. Also check for pending async exceptions (except unsafe access error).
1223 // Note only the native==>Java barriers can call this function when thread state
1224 // is _thread_in_native_trans.
1225 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1226   assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1227   assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1228 
1229   thread->set_thread_state(_thread_in_vm);
1230 
1231   // Enable WXWrite: called directly from interpreter native wrapper.
1232   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1233 
1234   SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1235 
1236   // After returning from native, it could be that the stack frames are not
1237   // yet safe to use. We catch such situations in the subsequent stack watermark
1238   // barrier, which will trap unsafe stack frames.
1239   StackWatermarkSet::before_unwind(thread);
1240 }
1241 
1242 #ifndef PRODUCT
1243 // Deoptimization
1244 // Function for testing deoptimization
1245 void JavaThread::deoptimize() {
1246   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1247   bool deopt = false;           // Dump stack only if a deopt actually happens.
1248   bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1249   // Iterate over all frames in the thread and deoptimize
1250   for (; !fst.is_done(); fst.next()) {
1251     if (fst.current()->can_be_deoptimized()) {
1252 
1253       if (only_at) {
1254         // Deoptimize only at particular bcis.  DeoptimizeOnlyAt
1255         // consists of comma or carriage return separated numbers so
1256         // search for the current bci in that string.
1257         address pc = fst.current()->pc();
1258         nmethod* nm =  (nmethod*) fst.current()->cb();
1259         ScopeDesc* sd = nm->scope_desc_at(pc);
1260         char buffer[8];
1261         jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1262         size_t len = strlen(buffer);
1263         const char * found = strstr(DeoptimizeOnlyAt, buffer);
1264         while (found != NULL) {
1265           if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1266               (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1267             // Check that the bci found is bracketed by terminators.
1268             break;
1269           }
1270           found = strstr(found + 1, buffer);
1271         }
1272         if (!found) {
1273           continue;
1274         }
1275       }
1276 
1277       if (DebugDeoptimization && !deopt) {
1278         deopt = true; // One-time only print before deopt
1279         tty->print_cr("[BEFORE Deoptimization]");
1280         trace_frames();
1281         trace_stack();
1282       }
1283       Deoptimization::deoptimize(this, *fst.current());
1284     }
1285   }
1286 
1287   if (DebugDeoptimization && deopt) {
1288     tty->print_cr("[AFTER Deoptimization]");
1289     trace_frames();
1290   }
1291 }
1292 
1293 
1294 // Make zombies
1295 void JavaThread::make_zombies() {
1296   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1297     if (fst.current()->can_be_deoptimized()) {
1298       // it is a Java nmethod
1299       nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1300       nm->make_not_entrant();
1301     }
1302   }
1303 }
1304 #endif // PRODUCT
1305 
1306 
1307 void JavaThread::deoptimize_marked_methods() {
1308   if (!has_last_Java_frame()) return;
1309   StackFrameStream fst(this, false /* update */, true /* process_frames */);
1310   for (; !fst.is_done(); fst.next()) {
1311     if (fst.current()->should_be_deoptimized()) {
1312       Deoptimization::deoptimize(this, *fst.current());
1313     }
1314   }
1315 }
1316 
1317 #ifdef ASSERT
1318 void JavaThread::verify_frame_info() {
1319   assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1320          (has_last_Java_frame() && java_call_counter() > 0),
1321          "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1322          has_last_Java_frame() ? "true" : "false", java_call_counter());
1323 }
1324 #endif
1325 
1326 // Push on a new block of JNI handles.
1327 void JavaThread::push_jni_handle_block() {
1328   // Allocate a new block for JNI handles.
1329   // Inlined code from jni_PushLocalFrame()
1330   JNIHandleBlock* old_handles = active_handles();
1331   JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1332   assert(old_handles != NULL && new_handles != NULL, "should not be NULL");
1333   new_handles->set_pop_frame_link(old_handles);  // make sure java handles get gc'd.
1334   set_active_handles(new_handles);
1335 }
1336 
1337 // Pop off the current block of JNI handles.
1338 void JavaThread::pop_jni_handle_block() {
1339   // Release our JNI handle block
1340   JNIHandleBlock* old_handles = active_handles();
1341   JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1342   assert(new_handles != nullptr, "should never set active handles to null");
1343   set_active_handles(new_handles);
1344   old_handles->set_pop_frame_link(NULL);
1345   JNIHandleBlock::release_block(old_handles, this);
1346 }
1347 
1348 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1349   // Verify that the deferred card marks have been flushed.
1350   assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1351 
1352   // Traverse the GCHandles
1353   Thread::oops_do_no_frames(f, cf);
1354 
1355   if (active_handles() != NULL) {
1356     active_handles()->oops_do(f);
1357   }
1358 
1359   DEBUG_ONLY(verify_frame_info();)
1360 
1361   if (has_last_Java_frame()) {
1362     // Traverse the monitor chunks
1363     for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1364       chunk->oops_do(f);
1365     }
1366   }
1367 
1368   assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
1369   // If we have deferred set_locals there might be oops waiting to be
1370   // written
1371   GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1372   if (list != NULL) {
1373     for (int i = 0; i < list->length(); i++) {
1374       list->at(i)->oops_do(f);
1375     }
1376   }
1377 
1378   // Traverse instance variables at the end since the GC may be moving things
1379   // around using this function
1380   f->do_oop((oop*) &_vm_result);
1381   f->do_oop((oop*) &_exception_oop);
1382 #if INCLUDE_JVMCI
1383   f->do_oop((oop*) &_jvmci_reserved_oop0);
1384 #endif
1385 
1386   if (jvmti_thread_state() != NULL) {
1387     jvmti_thread_state()->oops_do(f, cf);
1388   }
1389 
1390   // The continuation oops are really on the stack. But there is typically at most
1391   // one of those per thread, so we handle them here in the oops_do_no_frames part
1392   // so that we don't have to sprinkle as many stack watermark checks where these
1393   // oops are used. We just need to make sure the thread has started processing.
1394   ContinuationEntry* entry = _cont_entry;
1395   while (entry != nullptr) {
1396     f->do_oop((oop*)entry->cont_addr());
1397     f->do_oop((oop*)entry->chunk_addr());
1398     entry = entry->parent();
1399   }
1400 }
1401 
1402 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1403   if (!has_last_Java_frame()) {
1404     return;
1405   }
1406   // Finish any pending lazy GC activity for the frames
1407   StackWatermarkSet::finish_processing(this, NULL /* context */, StackWatermarkKind::gc);
1408   // Traverse the execution stack
1409   for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1410     fst.current()->oops_do(f, cf, fst.register_map());
1411   }
1412 }
1413 
1414 #ifdef ASSERT
1415 void JavaThread::verify_states_for_handshake() {
1416   // This checks that the thread has a correct frame state during a handshake.
1417   verify_frame_info();
1418 }
1419 #endif
1420 
1421 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1422   DEBUG_ONLY(verify_frame_info();)
1423   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1424 
1425   if (has_last_Java_frame()) {
1426     // Traverse the execution stack
1427     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1428       fst.current()->nmethods_do(cf);
1429     }
1430   }
1431 
1432   if (jvmti_thread_state() != NULL) {
1433     jvmti_thread_state()->nmethods_do(cf);
1434   }
1435 }
1436 
1437 void JavaThread::metadata_do(MetadataClosure* f) {
1438   if (has_last_Java_frame()) {
1439     // Traverse the execution stack to call f() on the methods in the stack
1440     for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1441       fst.current()->metadata_do(f);
1442     }
1443   } else if (is_Compiler_thread()) {
1444     // need to walk ciMetadata in current compile tasks to keep alive.
1445     CompilerThread* ct = (CompilerThread*)this;
1446     if (ct->env() != NULL) {
1447       ct->env()->metadata_do(f);
1448     }
1449     CompileTask* task = ct->task();
1450     if (task != NULL) {
1451       task->metadata_do(f);
1452     }
1453   }
1454 }
1455 
1456 // Printing
1457 const char* _get_thread_state_name(JavaThreadState _thread_state) {
1458   switch (_thread_state) {
1459   case _thread_uninitialized:     return "_thread_uninitialized";
1460   case _thread_new:               return "_thread_new";
1461   case _thread_new_trans:         return "_thread_new_trans";
1462   case _thread_in_native:         return "_thread_in_native";
1463   case _thread_in_native_trans:   return "_thread_in_native_trans";
1464   case _thread_in_vm:             return "_thread_in_vm";
1465   case _thread_in_vm_trans:       return "_thread_in_vm_trans";
1466   case _thread_in_Java:           return "_thread_in_Java";
1467   case _thread_in_Java_trans:     return "_thread_in_Java_trans";
1468   case _thread_blocked:           return "_thread_blocked";
1469   case _thread_blocked_trans:     return "_thread_blocked_trans";
1470   default:                        return "unknown thread state";
1471   }
1472 }
1473 
1474 void JavaThread::print_thread_state_on(outputStream *st) const {
1475   st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
1476 }
1477 
1478 const char* JavaThread::thread_state_name() const {
1479   return _get_thread_state_name(_thread_state);
1480 }
1481 
1482 // Called by Threads::print() for VM_PrintThreads operation
1483 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1484   st->print_raw("\"");
1485   st->print_raw(name());
1486   st->print_raw("\" ");
1487   oop thread_oop = threadObj();
1488   if (thread_oop != NULL) {
1489     st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1490     if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
1491     st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1492   }
1493   Thread::print_on(st, print_extended_info);
1494   // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1495   st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1496   if (thread_oop != NULL) {
1497     if (is_vthread_mounted()) {
1498       oop vt = vthread();
1499       assert(vt != NULL, "");
1500       st->print_cr("   Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1501     } else {
1502       st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1503     }
1504   }
1505 #ifndef PRODUCT
1506   _safepoint_state->print_on(st);
1507 #endif // PRODUCT
1508   if (is_Compiler_thread()) {
1509     CompileTask *task = ((CompilerThread*)this)->task();
1510     if (task != NULL) {
1511       st->print("   Compiling: ");
1512       task->print(st, NULL, true, false);
1513     } else {
1514       st->print("   No compile task");
1515     }
1516     st->cr();
1517   }
1518 }
1519 
1520 void JavaThread::print() const { print_on(tty); }
1521 
1522 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1523   st->print("%s", get_thread_name_string(buf, buflen));
1524 }
1525 
1526 // Called by fatal error handler. The difference between this and
1527 // JavaThread::print() is that we can't grab lock or allocate memory.
1528 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1529   st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1530   Thread* current = Thread::current_or_null_safe();
1531   assert(current != nullptr, "cannot be called by a detached thread");
1532   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1533     // Only access threadObj() if current thread is not a JavaThread
1534     // or if it is a JavaThread that can safely access oops.
1535     oop thread_obj = threadObj();
1536     if (thread_obj != nullptr) {
1537       if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
1538     }
1539   }
1540   st->print(" [");
1541   st->print("%s", _get_thread_state_name(_thread_state));
1542   if (osthread()) {
1543     st->print(", id=%d", osthread()->thread_id());
1544   }
1545   st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
1546             p2i(stack_end()), p2i(stack_base()));
1547   st->print("]");
1548 
1549   ThreadsSMRSupport::print_info_on(this, st);
1550   return;
1551 }
1552 
1553 
1554 // Verification
1555 
1556 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1557   // ignore if there is no stack
1558   if (!has_last_Java_frame()) return;
1559   // traverse the stack frames. Starts from top frame.
1560   for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1561     frame* fr = fst.current();
1562     f(fr, fst.register_map());
1563   }
1564 }
1565 
1566 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1567 
1568 void JavaThread::verify() {
1569   // Verify oops in the thread.
1570   oops_do(&VerifyOopClosure::verify_oop, NULL);
1571 
1572   // Verify the stack frames.
1573   frames_do(frame_verify);
1574 }
1575 
1576 // CR 6300358 (sub-CR 2137150)
1577 // Most callers of this method assume that it can't return NULL but a
1578 // thread may not have a name whilst it is in the process of attaching to
1579 // the VM - see CR 6412693, and there are places where a JavaThread can be
1580 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1581 // if vm exit occurs during initialization). These cases can all be accounted
1582 // for such that this method never returns NULL.
1583 const char* JavaThread::name() const  {
1584   if (Thread::is_JavaThread_protected(/* target */ this)) {
1585     // The target JavaThread is protected so get_thread_name_string() is safe:
1586     return get_thread_name_string();
1587   }
1588 
1589   // The target JavaThread is not protected so we return the default:
1590   return Thread::name();
1591 }
1592 
1593 // Returns a non-NULL representation of this thread's name, or a suitable
1594 // descriptive string if there is no set name.
1595 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1596   const char* name_str;
1597 #ifdef ASSERT
1598   Thread* current = Thread::current_or_null_safe();
1599   assert(current != nullptr, "cannot be called by a detached thread");
1600   if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1601     // Only access threadObj() if current thread is not a JavaThread
1602     // or if it is a JavaThread that can safely access oops.
1603 #endif
1604     oop thread_obj = threadObj();
1605     if (thread_obj != NULL) {
1606       oop name = java_lang_Thread::name(thread_obj);
1607       if (name != NULL) {
1608         if (buf == NULL) {
1609           name_str = java_lang_String::as_utf8_string(name);
1610         } else {
1611           name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1612         }
1613       } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1614         name_str = "<no-name - thread is attaching>";
1615       } else {
1616         name_str = "<un-named>";
1617       }
1618     } else {
1619       name_str = Thread::name();
1620     }
1621 #ifdef ASSERT
1622   } else {
1623     // Current JavaThread has exited...
1624     if (current == this) {
1625       // ... and is asking about itself:
1626       name_str = "<no-name - current JavaThread has exited>";
1627     } else {
1628       // ... and it can't safely determine this JavaThread's name so
1629       // use the default thread name.
1630       name_str = Thread::name();
1631     }
1632   }
1633 #endif
1634   assert(name_str != NULL, "unexpected NULL thread name");
1635   return name_str;
1636 }
1637 
1638 // Helper to extract the name from the thread oop for logging.
1639 const char* JavaThread::name_for(oop thread_obj) {
1640   assert(thread_obj != NULL, "precondition");
1641   oop name = java_lang_Thread::name(thread_obj);
1642   const char* name_str;
1643   if (name != NULL) {
1644     name_str = java_lang_String::as_utf8_string(name);
1645   } else {
1646     name_str = "<un-named>";
1647   }
1648   return name_str;
1649 }
1650 
1651 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1652 
1653   assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1654   assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1655   // Link Java Thread object <-> C++ Thread
1656 
1657   // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1658   // and put it into a new Handle.  The Handle "thread_oop" can then
1659   // be used to pass the C++ thread object to other methods.
1660 
1661   // Set the Java level thread object (jthread) field of the
1662   // new thread (a JavaThread *) to C++ thread object using the
1663   // "thread_oop" handle.
1664 
1665   // Set the thread field (a JavaThread *) of the
1666   // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1667 
1668   Handle thread_oop(Thread::current(),
1669                     JNIHandles::resolve_non_null(jni_thread));
1670   assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1671          "must be initialized");
1672   set_threadOopHandles(thread_oop());
1673   java_lang_Thread::set_thread(thread_oop(), this);
1674 
1675   if (prio == NoPriority) {
1676     prio = java_lang_Thread::priority(thread_oop());
1677     assert(prio != NoPriority, "A valid priority should be present");
1678   }
1679 
1680   // Push the Java priority down to the native thread; needs Threads_lock
1681   Thread::set_priority(this, prio);
1682 
1683   // Add the new thread to the Threads list and set it in motion.
1684   // We must have threads lock in order to call Threads::add.
1685   // It is crucial that we do not block before the thread is
1686   // added to the Threads list for if a GC happens, then the java_thread oop
1687   // will not be visited by GC.
1688   Threads::add(this);
1689 }
1690 
1691 oop JavaThread::current_park_blocker() {
1692   // Support for JSR-166 locks
1693   oop thread_oop = threadObj();
1694   if (thread_oop != NULL) {
1695     return java_lang_Thread::park_blocker(thread_oop);
1696   }
1697   return NULL;
1698 }
1699 
1700 
1701 void JavaThread::print_stack_on(outputStream* st) {
1702   if (!has_last_Java_frame()) return;
1703 
1704   Thread* current_thread = Thread::current();
1705   ResourceMark rm(current_thread);
1706   HandleMark hm(current_thread);
1707 
1708   RegisterMap reg_map(this,
1709                       RegisterMap::UpdateMap::include,
1710                       RegisterMap::ProcessFrames::include,
1711                       RegisterMap::WalkContinuation::skip);
1712   vframe* start_vf = platform_thread_last_java_vframe(&reg_map);
1713   int count = 0;
1714   for (vframe* f = start_vf; f != NULL; f = f->sender()) {
1715     if (f->is_java_frame()) {
1716       javaVFrame* jvf = javaVFrame::cast(f);
1717       java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1718 
1719       // Print out lock information
1720       if (JavaMonitorsInStackTrace) {
1721         jvf->print_lock_info_on(st, count);
1722       }
1723     } else {
1724       // Ignore non-Java frames
1725     }
1726 
1727     // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1728     count++;
1729     if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1730   }
1731 }
1732 
1733 #if INCLUDE_JVMTI
1734 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1735 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1736   set_jvmti_vthread(thread_oop);
1737 
1738   // unbind current JvmtiThreadState from JavaThread
1739   JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1740 
1741   // bind new JvmtiThreadState to JavaThread
1742   JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1743 
1744   return jvmti_thread_state();
1745 }
1746 #endif
1747 
1748 // JVMTI PopFrame support
1749 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1750   assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
1751   if (in_bytes(size_in_bytes) != 0) {
1752     _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1753     _popframe_preserved_args_size = in_bytes(size_in_bytes);
1754     Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1755   }
1756 }
1757 
1758 void* JavaThread::popframe_preserved_args() {
1759   return _popframe_preserved_args;
1760 }
1761 
1762 ByteSize JavaThread::popframe_preserved_args_size() {
1763   return in_ByteSize(_popframe_preserved_args_size);
1764 }
1765 
1766 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1767   int sz = in_bytes(popframe_preserved_args_size());
1768   assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1769   return in_WordSize(sz / wordSize);
1770 }
1771 
1772 void JavaThread::popframe_free_preserved_args() {
1773   assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
1774   FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1775   _popframe_preserved_args = NULL;
1776   _popframe_preserved_args_size = 0;
1777 }
1778 
1779 #ifndef PRODUCT
1780 
1781 void JavaThread::trace_frames() {
1782   tty->print_cr("[Describe stack]");
1783   int frame_no = 1;
1784   for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1785     tty->print("  %d. ", frame_no++);
1786     fst.current()->print_value_on(tty, this);
1787     tty->cr();
1788   }
1789 }
1790 
1791 class PrintAndVerifyOopClosure: public OopClosure {
1792  protected:
1793   template <class T> inline void do_oop_work(T* p) {
1794     oop obj = RawAccess<>::oop_load(p);
1795     if (obj == NULL) return;
1796     tty->print(INTPTR_FORMAT ": ", p2i(p));
1797     if (oopDesc::is_oop_or_null(obj)) {
1798       if (obj->is_objArray()) {
1799         tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1800       } else {
1801         obj->print();
1802       }
1803     } else {
1804       tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1805     }
1806     tty->cr();
1807   }
1808  public:
1809   virtual void do_oop(oop* p) { do_oop_work(p); }
1810   virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
1811 };
1812 
1813 #ifdef ASSERT
1814 // Print or validate the layout of stack frames
1815 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1816   ResourceMark rm;
1817   PreserveExceptionMark pm(this);
1818   FrameValues values;
1819   int frame_no = 0;
1820   for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1821     fst.current()->describe(values, ++frame_no, fst.register_map());
1822     if (depth == frame_no) break;
1823   }
1824   Continuation::describe(values);
1825   if (validate_only) {
1826     values.validate();
1827   } else {
1828     tty->print_cr("[Describe stack layout]");
1829     values.print(this);
1830   }
1831 }
1832 #endif
1833 
1834 void JavaThread::trace_stack_from(vframe* start_vf) {
1835   ResourceMark rm;
1836   int vframe_no = 1;
1837   for (vframe* f = start_vf; f; f = f->sender()) {
1838     if (f->is_java_frame()) {
1839       javaVFrame::cast(f)->print_activation(vframe_no++);
1840     } else {
1841       f->print();
1842     }
1843     if (vframe_no > StackPrintLimit) {
1844       tty->print_cr("...<more frames>...");
1845       return;
1846     }
1847   }
1848 }
1849 
1850 
1851 void JavaThread::trace_stack() {
1852   if (!has_last_Java_frame()) return;
1853   Thread* current_thread = Thread::current();
1854   ResourceMark rm(current_thread);
1855   HandleMark hm(current_thread);
1856   RegisterMap reg_map(this,
1857                       RegisterMap::UpdateMap::include,
1858                       RegisterMap::ProcessFrames::include,
1859                       RegisterMap::WalkContinuation::skip);
1860   trace_stack_from(last_java_vframe(&reg_map));
1861 }
1862 
1863 
1864 #endif // PRODUCT
1865 
1866 void JavaThread::inc_held_monitor_count(int i, bool jni) {
1867 #ifdef SUPPORT_MONITOR_COUNT
1868   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1869   _held_monitor_count += i;
1870   if (jni) {
1871     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1872     _jni_monitor_count += i;
1873   }
1874 #endif
1875 }
1876 
1877 void JavaThread::dec_held_monitor_count(int i, bool jni) {
1878 #ifdef SUPPORT_MONITOR_COUNT
1879   _held_monitor_count -= i;
1880   assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1881   if (jni) {
1882     _jni_monitor_count -= i;
1883     assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1884   }
1885 #endif
1886 }
1887 
1888 frame JavaThread::vthread_last_frame() {
1889   assert (is_vthread_mounted(), "Virtual thread not mounted");
1890   return last_frame();
1891 }
1892 
1893 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1894   const ContinuationEntry* entry = vthread_continuation();
1895   guarantee (entry != NULL, "Not a carrier thread");
1896   frame f = entry->to_frame();
1897   if (reg_map->process_frames()) {
1898     entry->flush_stack_processing(this);
1899   }
1900   entry->update_register_map(reg_map);
1901   return f.sender(reg_map);
1902 }
1903 
1904 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1905   return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1906 }
1907 
1908 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
1909   assert(reg_map != NULL, "a map must be given");
1910   for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
1911     if (vf->is_java_frame()) return javaVFrame::cast(vf);
1912   }
1913   return NULL;
1914 }
1915 
1916 oop JavaThread::get_continuation() const {
1917   assert(threadObj() != nullptr, "must be set");
1918   return java_lang_Thread::continuation(threadObj());
1919 }
1920 
1921 Klass* JavaThread::security_get_caller_class(int depth) {
1922   ResetNoHandleMark rnhm;
1923   HandleMark hm(Thread::current());
1924 
1925   vframeStream vfst(this);
1926   vfst.security_get_caller_frame(depth);
1927   if (!vfst.at_end()) {
1928     return vfst.method()->method_holder();
1929   }
1930   return NULL;
1931 }
1932 
1933 // java.lang.Thread.sleep support
1934 // Returns true if sleep time elapsed as expected, and false
1935 // if the thread was interrupted.
1936 bool JavaThread::sleep(jlong millis) {
1937   assert(this == Thread::current(),  "thread consistency check");
1938 
1939   ParkEvent * const slp = this->_SleepEvent;
1940   // Because there can be races with thread interruption sending an unpark()
1941   // to the event, we explicitly reset it here to avoid an immediate return.
1942   // The actual interrupt state will be checked before we park().
1943   slp->reset();
1944   // Thread interruption establishes a happens-before ordering in the
1945   // Java Memory Model, so we need to ensure we synchronize with the
1946   // interrupt state.
1947   OrderAccess::fence();
1948 
1949   jlong prevtime = os::javaTimeNanos();
1950 
1951   for (;;) {
1952     // interruption has precedence over timing out
1953     if (this->is_interrupted(true)) {
1954       return false;
1955     }
1956 
1957     if (millis <= 0) {
1958       return true;
1959     }
1960 
1961     {
1962       ThreadBlockInVM tbivm(this);
1963       OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1964       slp->park(millis);
1965     }
1966 
1967     // Update elapsed time tracking
1968     jlong newtime = os::javaTimeNanos();
1969     if (newtime - prevtime < 0) {
1970       // time moving backwards, should only happen if no monotonic clock
1971       // not a guarantee() because JVM should not abort on kernel/glibc bugs
1972       assert(false,
1973              "unexpected time moving backwards detected in JavaThread::sleep()");
1974     } else {
1975       millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
1976     }
1977     prevtime = newtime;
1978   }
1979 }
1980 
1981 // Last thread running calls java.lang.Shutdown.shutdown()
1982 void JavaThread::invoke_shutdown_hooks() {
1983   HandleMark hm(this);
1984 
1985   // We could get here with a pending exception, if so clear it now or
1986   // it will cause MetaspaceShared::link_shared_classes to
1987   // fail for dynamic dump.
1988   if (this->has_pending_exception()) {
1989     this->clear_pending_exception();
1990   }
1991 
1992 #if INCLUDE_CDS
1993   // Link all classes for dynamic CDS dumping before vm exit.
1994   // Same operation is being done in JVM_BeforeHalt for handling the
1995   // case where the application calls System.exit().
1996   if (DynamicArchive::should_dump_at_vm_exit()) {
1997     DynamicArchive::prepare_for_dump_at_exit();
1998   }
1999 #endif
2000 
2001   EXCEPTION_MARK;
2002   Klass* shutdown_klass =
2003     SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2004                                       THREAD);
2005   if (shutdown_klass != NULL) {
2006     // SystemDictionary::resolve_or_null will return null if there was
2007     // an exception.  If we cannot load the Shutdown class, just don't
2008     // call Shutdown.shutdown() at all.  This will mean the shutdown hooks
2009     // won't be run.  Note that if a shutdown hook was registered,
2010     // the Shutdown class would have already been loaded
2011     // (Runtime.addShutdownHook will load it).
2012     JavaValue result(T_VOID);
2013     JavaCalls::call_static(&result,
2014                            shutdown_klass,
2015                            vmSymbols::shutdown_name(),
2016                            vmSymbols::void_method_signature(),
2017                            THREAD);
2018   }
2019   CLEAR_PENDING_EXCEPTION;
2020 }
2021 
2022 #ifndef PRODUCT
2023 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2024    report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2025 }
2026 #endif
2027 
2028 // Helper function to create the java.lang.Thread object for a
2029 // VM-internal thread. The thread will have the given name, and be
2030 // a member of the "system" ThreadGroup.
2031 Handle JavaThread::create_system_thread_object(const char* name,
2032                                                bool is_visible, TRAPS) {
2033   Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2034 
2035   // Initialize thread_oop to put it into the system threadGroup.
2036   // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2037   Handle thread_group(THREAD, Universe::system_thread_group());
2038   Handle thread_oop =
2039     JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2040                                       vmSymbols::threadgroup_string_void_signature(),
2041                                       thread_group,
2042                                       string,
2043                                       CHECK_NH);
2044 
2045   return thread_oop;
2046 }
2047 
2048 // Starts the target JavaThread as a daemon of the given priority, and
2049 // bound to the given java.lang.Thread instance.
2050 // The Threads_lock is held for the duration.
2051 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2052                                        Handle thread_oop, ThreadPriority prio) {
2053 
2054   assert(target->osthread() != NULL, "target thread is not properly initialized");
2055 
2056   MutexLocker mu(current, Threads_lock);
2057 
2058   // Initialize the fields of the thread_oop first.
2059 
2060   java_lang_Thread::set_thread(thread_oop(), target); // isAlive == true now
2061 
2062   if (prio != NoPriority) {
2063     java_lang_Thread::set_priority(thread_oop(), prio);
2064     // Note: we don't call os::set_priority here. Possibly we should,
2065     // else all threads should call it themselves when they first run.
2066   }
2067 
2068   java_lang_Thread::set_daemon(thread_oop());
2069 
2070   // Now bind the thread_oop to the target JavaThread.
2071   target->set_threadOopHandles(thread_oop());
2072 
2073   Threads::add(target); // target is now visible for safepoint/handshake
2074   Thread::start(target);
2075 }
2076 
2077 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2078   // At this point it may be possible that no osthread was created for the
2079   // JavaThread due to lack of resources. However, since this must work
2080   // for critical system threads just check and abort if this fails.
2081   if (thread->osthread() == nullptr) {
2082     // This isn't really an OOM condition, but historically this is what
2083     // we report.
2084     vm_exit_during_initialization("java.lang.OutOfMemoryError",
2085                                   os::native_thread_creation_failed_msg());
2086   }
2087 }
2088 
2089 // Deferred OopHandle release support.
2090 
2091 class OopHandleList : public CHeapObj<mtInternal> {
2092   static const int _count = 4;
2093   OopHandle _handles[_count];
2094   OopHandleList* _next;
2095   int _index;
2096  public:
2097   OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2098   void add(OopHandle h) {
2099     assert(_index < _count, "too many additions");
2100     _handles[_index++] = h;
2101   }
2102   ~OopHandleList() {
2103     assert(_index == _count, "usage error");
2104     for (int i = 0; i < _index; i++) {
2105       _handles[i].release(JavaThread::thread_oop_storage());
2106     }
2107   }
2108   OopHandleList* next() const { return _next; }
2109 };
2110 
2111 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2112 
2113 // Called by the ServiceThread to do the work of releasing
2114 // the OopHandles.
2115 void JavaThread::release_oop_handles() {
2116   OopHandleList* list;
2117   {
2118     MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2119     list = _oop_handle_list;
2120     _oop_handle_list = nullptr;
2121   }
2122   assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2123 
2124   while (list != nullptr) {
2125     OopHandleList* l = list;
2126     list = l->next();
2127     delete l;
2128   }
2129 }
2130 
2131 // Add our OopHandles for later release.
2132 void JavaThread::add_oop_handles_for_release() {
2133   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2134   OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2135   new_head->add(_threadObj);
2136   new_head->add(_vthread);
2137   new_head->add(_jvmti_vthread);
2138   new_head->add(_scopedValueCache);
2139   _oop_handle_list = new_head;
2140   Service_lock->notify_all();
2141 }