1 /*
   2  * Copyright (c) 1997, 2024, 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 #ifndef SHARE_RUNTIME_JAVATHREAD_HPP
  27 #define SHARE_RUNTIME_JAVATHREAD_HPP
  28 
  29 #include "jni.h"
  30 #include "memory/allocation.hpp"
  31 #include "oops/oop.hpp"
  32 #include "oops/oopHandle.hpp"
  33 #include "runtime/continuationEntry.hpp"
  34 #include "runtime/frame.hpp"
  35 #include "runtime/globals.hpp"
  36 #include "runtime/handshake.hpp"
  37 #include "runtime/javaFrameAnchor.hpp"
  38 #include "runtime/lockStack.hpp"
  39 #include "runtime/park.hpp"
  40 #include "utilities/ticks.hpp"
  41 #include "runtime/safepointMechanism.hpp"
  42 #include "runtime/stackWatermarkSet.hpp"
  43 #include "runtime/stackOverflow.hpp"
  44 #include "runtime/thread.hpp"
  45 #include "runtime/threadHeapSampler.hpp"
  46 #include "runtime/threadIdentifier.hpp"
  47 #include "runtime/threadStatisticalInfo.hpp"
  48 #include "utilities/exceptions.hpp"
  49 #include "utilities/globalDefinitions.hpp"
  50 #include "utilities/macros.hpp"
  51 #if INCLUDE_JFR
  52 #include "jfr/support/jfrThreadExtension.hpp"
  53 #endif
  54 
  55 class AsyncExceptionHandshake;
  56 class DeoptResourceMark;
  57 class InternalOOMEMark;
  58 class JNIHandleBlock;
  59 class JVMCIRuntime;
  60 
  61 class JvmtiDeferredUpdates;
  62 class JvmtiSampledObjectAllocEventCollector;
  63 class JvmtiThreadState;
  64 
  65 class Metadata;
  66 class ObjectMonitor;
  67 class OopHandleList;
  68 class OopStorage;
  69 class OSThread;
  70 
  71 class ThreadsList;
  72 class ThreadSafepointState;
  73 class ThreadStatistics;
  74 
  75 class vframeArray;
  76 class vframe;
  77 class javaVFrame;
  78 
  79 class JavaThread;
  80 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
  81 
  82 class EventVirtualThreadPinned;
  83 
  84 class JavaThread: public Thread {
  85   friend class VMStructs;
  86   friend class JVMCIVMStructs;
  87   friend class WhiteBox;
  88   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
  89   friend class HandshakeState;
  90   friend class Continuation;
  91   friend class Threads;
  92   friend class ServiceThread; // for deferred OopHandle release access
  93  private:
  94   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
  95 
  96   // All references to Java objects managed via OopHandles. These
  97   // have to be released by the ServiceThread after the JavaThread has
  98   // terminated - see add_oop_handles_for_release().
  99   OopHandle      _threadObj;                     // The Java level thread object
 100   OopHandle      _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
 101   OopHandle      _jvmti_vthread;
 102   OopHandle      _scopedValueCache;
 103 
 104   static OopStorage* _thread_oop_storage;
 105 
 106 #ifdef ASSERT
 107  private:
 108   int _java_call_counter;
 109 
 110  public:
 111   int  java_call_counter()                       { return _java_call_counter; }
 112   void inc_java_call_counter()                   { _java_call_counter++; }
 113   void dec_java_call_counter() {
 114     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 115     _java_call_counter--;
 116   }
 117  private:  // restore original namespace restriction
 118 #endif  // ifdef ASSERT
 119 
 120   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 121 
 122   ThreadFunction _entry_point;
 123 
 124   JNIEnv        _jni_environment;
 125 
 126   // Deopt support
 127   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 128 
 129   nmethod*      _deopt_nmethod;                  // nmethod that is currently being deoptimized
 130   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 131   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 132   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
 133   // will be carried out as soon as possible which, in most cases, is just before deoptimization of
 134   // the frame, when control returns to it.
 135   JvmtiDeferredUpdates* _jvmti_deferred_updates;
 136 
 137   // Handshake value for fixing 6243940. We need a place for the i2c
 138   // adapter to store the callee Method*. This value is NEVER live
 139   // across a gc point so it does NOT have to be gc'd
 140   // The handshake is open ended since we can't be certain that it will
 141   // be nulled. This is because we rarely ever see the race and end up
 142   // in handle_wrong_method which is the backend of the handshake. See
 143   // code in i2c adapters and handle_wrong_method.
 144 
 145   Method*       _callee_target;
 146 
 147   // Used to pass back results to the interpreter or generated code running Java code.
 148   oop           _vm_result;    // oop result is GC-preserved
 149   Metadata*     _vm_result_2;  // non-oop result
 150 
 151   // See ReduceInitialCardMarks: this holds the precise space interval of
 152   // the most recent slow path allocation for which compiled code has
 153   // elided card-marks for performance along the fast-path.
 154   MemRegion     _deferred_card_mark;
 155 
 156   ObjectMonitor* volatile _current_pending_monitor;     // ObjectMonitor this thread is waiting to lock
 157   bool           _current_pending_monitor_is_from_java; // locking is from Java code
 158   ObjectMonitor* volatile _current_waiting_monitor;     // ObjectMonitor on which this thread called Object.wait()
 159 
 160   // Active_handles points to a block of handles
 161   JNIHandleBlock* _active_handles;
 162 
 163   // One-element thread local free list
 164   JNIHandleBlock* _free_handle_block;
 165 
 166   // ID used as owner for inflated monitors. Same as the j.l.Thread.tid of the
 167   // current _vthread object, except during creation of the primordial and JNI
 168   // attached thread cases where this field can have a temporary value. Also,
 169   // calls to VirtualThread.switchToCarrierThread will temporarily change _vthread
 170   // to refer to the carrier while preserving the j.l.Thread.tid of the virtual
 171   // thread in this field.
 172   int64_t _lock_id;
 173 
 174  public:
 175   void set_lock_id(int64_t tid) {
 176     assert(tid >= ThreadIdentifier::initial() && tid < ThreadIdentifier::current(), "invalid tid");
 177     _lock_id = tid;
 178   }
 179   int64_t lock_id() const { return _lock_id; }
 180 
 181   // For tracking the heavyweight monitor the thread is pending on.
 182   ObjectMonitor* current_pending_monitor() {
 183     // Use Atomic::load() to prevent data race between concurrent modification and
 184     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 185     // Especially, reloading pointer from thread after null check must be prevented.
 186     return Atomic::load(&_current_pending_monitor);
 187   }
 188   void set_current_pending_monitor(ObjectMonitor* monitor) {
 189     Atomic::store(&_current_pending_monitor, monitor);
 190   }
 191   void set_current_pending_monitor_is_from_java(bool from_java) {
 192     _current_pending_monitor_is_from_java = from_java;
 193   }
 194   bool current_pending_monitor_is_from_java() {
 195     return _current_pending_monitor_is_from_java;
 196   }
 197   ObjectMonitor* current_waiting_monitor() {
 198     // See the comment in current_pending_monitor() above.
 199     return Atomic::load(&_current_waiting_monitor);
 200   }
 201   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 202     Atomic::store(&_current_waiting_monitor, monitor);
 203   }
 204 
 205   // JNI handle support
 206   JNIHandleBlock* active_handles() const         { return _active_handles; }
 207   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 208   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 209   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 210 
 211   void push_jni_handle_block();
 212   void pop_jni_handle_block();
 213 
 214  private:
 215   enum SuspendFlags {
 216     // NOTE: avoid using the sign-bit as cc generates different test code
 217     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 218     _trace_flag             = 0x00000004U, // call tracing backend
 219     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 220   };
 221 
 222   // various suspension related flags - atomically updated
 223   volatile uint32_t _suspend_flags;
 224 
 225   inline void set_suspend_flag(SuspendFlags f);
 226   inline void clear_suspend_flag(SuspendFlags f);
 227 
 228  public:
 229   inline void set_trace_flag();
 230   inline void clear_trace_flag();
 231   inline void set_obj_deopt_flag();
 232   inline void clear_obj_deopt_flag();
 233   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 234   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 235 
 236   // Asynchronous exception support
 237  private:
 238   friend class InstallAsyncExceptionHandshake;
 239   friend class AsyncExceptionHandshake;
 240   friend class HandshakeState;
 241 
 242   void handle_async_exception(oop java_throwable);
 243  public:
 244   void install_async_exception(AsyncExceptionHandshake* aec = nullptr);
 245   bool has_async_exception_condition();
 246   inline void set_pending_unsafe_access_error();
 247   static void send_async_exception(JavaThread* jt, oop java_throwable);
 248 
 249   class NoAsyncExceptionDeliveryMark : public StackObj {
 250     friend JavaThread;
 251     JavaThread *_target;
 252     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 253     inline ~NoAsyncExceptionDeliveryMark();
 254   };
 255 
 256   // Safepoint support
 257  public:                                                        // Expose _thread_state for SafeFetchInt()
 258   volatile JavaThreadState _thread_state;
 259   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 260   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 261   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 262 #ifdef ASSERT
 263   // Debug support for checking if code allows safepoints or not.
 264   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 265   // mutex, or blocking on an object synchronizer (Java locking).
 266   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 267   // the above cases. The class NoSafepointVerifier is used to set this counter.
 268   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 269 
 270  public:
 271   void inc_no_safepoint_count() { _no_safepoint_count++; }
 272   void dec_no_safepoint_count() { _no_safepoint_count--; }
 273   bool is_in_no_safepoint_scope() { return _no_safepoint_count > 0; }
 274 #endif // ASSERT
 275  public:
 276   // These functions check conditions before possibly going to a safepoint.
 277   // including NoSafepointVerifier.
 278   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 279   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 280 
 281 #ifdef ASSERT
 282  private:
 283   volatile uint64_t _visited_for_critical_count;
 284 
 285  public:
 286   void set_visited_for_critical_count(uint64_t safepoint_id) {
 287     assert(_visited_for_critical_count == 0, "Must be reset before set");
 288     assert((safepoint_id & 0x1) == 1, "Must be odd");
 289     _visited_for_critical_count = safepoint_id;
 290   }
 291   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 292     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 293     _visited_for_critical_count = 0;
 294   }
 295   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 296     return _visited_for_critical_count == safepoint_id;
 297   }
 298 #endif // ASSERT
 299 
 300   // JavaThread termination support
 301  public:
 302   enum TerminatedTypes {
 303     _not_terminated = 0xDEAD - 3,
 304     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 305     _thread_gc_barrier_detached,                 // thread's GC barrier has been detached
 306     _thread_terminated,                          // JavaThread is removed from thread list
 307     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 308                                                  // only VM_Exit can set _vm_exited
 309   };
 310 
 311  private:
 312   // In general a JavaThread's _terminated field transitions as follows:
 313   //
 314   //   _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
 315   //
 316   // _vm_exited is a special value to cover the case of a JavaThread
 317   // executing native code after the VM itself is terminated.
 318   //
 319   // A JavaThread that fails to JNI attach has these _terminated field transitions:
 320   //   _not_terminated => _thread_terminated
 321   //
 322   volatile TerminatedTypes _terminated;
 323 
 324   jint                  _in_deopt_handler;       // count of deoptimization
 325                                                  // handlers thread is in
 326   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 327   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 328                                                          // never locked) when throwing an exception. Used by interpreter only.
 329 #if INCLUDE_JVMTI
 330   volatile bool         _carrier_thread_suspended;       // Carrier thread is externally suspended
 331   bool                  _is_in_VTMS_transition;          // thread is in virtual thread mount state transition
 332   bool                  _is_in_tmp_VTMS_transition;      // thread is in temporary virtual thread mount state transition
 333   bool                  _is_disable_suspend;             // JVMTI suspend is temporarily disabled; used on current thread only
 334   bool                  _VTMS_transition_mark;           // used for sync between VTMS transitions and disablers
 335   bool                  _pending_jvmti_unmount_event;    // When preempting we post unmount event at unmount end rather than start
 336   bool                  _on_monitor_waited_event;        // Avoid callee arg processing for enterSpecial when posting waited event
 337   ObjectMonitor*        _contended_entered_monitor;      // Monitor for pending monitor_contended_entered callback
 338 #ifdef ASSERT
 339   bool                  _is_VTMS_transition_disabler;    // thread currently disabled VTMS transitions
 340 #endif
 341 #endif
 342 
 343   // JNI attach states:
 344   enum JNIAttachStates {
 345     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 346     _attaching_via_jni,          // thread is attaching via JNI
 347     _attached_via_jni            // thread has attached via JNI
 348   };
 349 
 350   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 351   // A native thread that is attaching via JNI starts with a value
 352   // of _attaching_via_jni and transitions to _attached_via_jni.
 353   volatile JNIAttachStates _jni_attach_state;
 354 
 355   // In scope of an InternalOOMEMark?
 356   bool _is_in_internal_oome_mark;
 357 
 358 #if INCLUDE_JVMCI
 359   // The _pending_* fields below are used to communicate extra information
 360   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 361 
 362   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 363   int       _pending_deoptimization;
 364 
 365   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 366   // before the monitor has been acquired.
 367   bool      _pending_monitorenter;
 368 
 369   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 370   bool      _pending_transfer_to_interpreter;
 371 
 372   // An id of a speculation that JVMCI compiled code can use to further describe and
 373   // uniquely identify the speculative optimization guarded by an uncommon trap.
 374   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 375   jlong     _pending_failed_speculation;
 376 
 377   // These fields are mutually exclusive in terms of live ranges.
 378   union {
 379     // Communicates the pc at which the most recent implicit exception occurred
 380     // from the signal handler to a deoptimization stub.
 381     address   _implicit_exception_pc;
 382 
 383     // Communicates an alternative call target to an i2c stub from a JavaCall .
 384     address   _alternate_call_target;
 385   } _jvmci;
 386 
 387   // The JVMCIRuntime in a JVMCI shared library
 388   JVMCIRuntime* _libjvmci_runtime;
 389 
 390   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 391   jlong*    _jvmci_counters;
 392 
 393   // Fast thread locals for use by JVMCI
 394   jlong      _jvmci_reserved0;
 395   jlong      _jvmci_reserved1;
 396   oop        _jvmci_reserved_oop0;
 397 
 398   // This field is used to keep an nmethod visible to the GC so that it and its contained oops can
 399   // be kept alive
 400   nmethod*  _live_nmethod;
 401 
 402  public:
 403   static jlong* _jvmci_old_thread_counters;
 404   static void collect_counters(jlong* array, int length);
 405 
 406   bool resize_counters(int current_size, int new_size);
 407 
 408   static bool resize_all_jvmci_counters(int new_size);
 409 
 410   void set_jvmci_reserved_oop0(oop value) {
 411     _jvmci_reserved_oop0 = value;
 412   }
 413 
 414   oop get_jvmci_reserved_oop0() {
 415     return _jvmci_reserved_oop0;
 416   }
 417 
 418   void set_jvmci_reserved0(jlong value) {
 419     _jvmci_reserved0 = value;
 420   }
 421 
 422   jlong get_jvmci_reserved0() {
 423     return _jvmci_reserved0;
 424   }
 425 
 426   void set_jvmci_reserved1(jlong value) {
 427     _jvmci_reserved1 = value;
 428   }
 429 
 430   jlong get_jvmci_reserved1() {
 431     return _jvmci_reserved1;
 432   }
 433 
 434   void set_live_nmethod(nmethod* nm) {
 435     assert(_live_nmethod == nullptr, "only one");
 436     _live_nmethod = nm;
 437   }
 438 
 439   void clear_live_nmethod() {
 440     _live_nmethod = nullptr;
 441   }
 442 
 443  private:
 444 #endif // INCLUDE_JVMCI
 445 
 446   StackOverflow    _stack_overflow_state;
 447 
 448   void pretouch_stack();
 449 
 450   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 451   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 452   // code)
 453   volatile oop     _exception_oop;               // Exception thrown in compiled code
 454   volatile address _exception_pc;                // PC where exception happened
 455   volatile address _exception_handler_pc;        // PC for handler of exception
 456   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 457 
 458  private:
 459   // support for JNI critical regions
 460   jint    _jni_active_critical;                  // count of entries into JNI critical region
 461 
 462   // Checked JNI: function name requires exception check
 463   char* _pending_jni_exception_check_fn;
 464 
 465   // For deadlock detection.
 466   int _depth_first_number;
 467 
 468   // JVMTI PopFrame support
 469   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 470   int _popframe_condition;
 471 
 472   // If reallocation of scalar replaced objects fails, we throw OOM
 473   // and during exception propagation, pop the top
 474   // _frames_to_pop_failed_realloc frames, the ones that reference
 475   // failed reallocations.
 476   int _frames_to_pop_failed_realloc;
 477 
 478   ContinuationEntry* _cont_entry;
 479   intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub frame inside the
 480                             // continuation that we know about
 481   int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
 482 
 483   // It's signed for error detection.
 484   intx _held_monitor_count;  // used by continuations for fast lock detection
 485   intx _jni_monitor_count;
 486   ObjectMonitor* _unlocked_inflated_monitor;
 487 
 488   // This is the field we poke in the interpreter and native
 489   // wrapper (Object.wait) to check for preemption.
 490   address _preempt_alternate_return;
 491   // When preempting on monitorenter we could have acquired the
 492   // monitor after freezing all vthread frames. In that case we
 493   // set this field so that in the preempt stub we call thaw again
 494   // instead of unmounting.
 495   bool _preemption_cancelled;
 496   // For Object.wait() we set this field to know if we need to
 497   // throw IE at the end of thawing before returning to Java.
 498   bool _pending_interrupted_exception;
 499 
 500  public:
 501   bool preemption_cancelled()           { return _preemption_cancelled; }
 502   void set_preemption_cancelled(bool b) { _preemption_cancelled = b; }
 503 
 504   bool pending_interrupted_exception()           { return _pending_interrupted_exception; }
 505   void set_pending_interrupted_exception(bool b) { _pending_interrupted_exception = b; }
 506 
 507   bool preempting()           { return _preempt_alternate_return != nullptr; }
 508   void set_preempt_alternate_return(address val) { _preempt_alternate_return = val; }
 509 
 510 private:
 511 
 512   friend class VMThread;
 513   friend class ThreadWaitTransition;
 514   friend class VM_Exit;
 515 
 516   // Stack watermark barriers.
 517   StackWatermarks _stack_watermarks;
 518 
 519  public:
 520   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
 521 
 522  public:
 523   // Constructor
 524   JavaThread(MemTag mem_tag = mtThread);   // delegating constructor
 525   JavaThread(ThreadFunction entry_point, size_t stack_size = 0, MemTag mem_tag = mtThread);
 526   ~JavaThread();
 527 
 528   // Factory method to create a new JavaThread whose attach state is "is attaching"
 529   static JavaThread* create_attaching_thread();
 530 
 531 #ifdef ASSERT
 532   // verify this JavaThread hasn't be published in the Threads::list yet
 533   void verify_not_published();
 534 #endif // ASSERT
 535 
 536   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
 537 
 538   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 539   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 540     _jni_environment.functions = functionTable;
 541   }
 542   struct JNINativeInterface_* get_jni_functions() {
 543     return (struct JNINativeInterface_ *)_jni_environment.functions;
 544   }
 545 
 546   // This function is called at thread creation to allow
 547   // platform specific thread variables to be initialized.
 548   void cache_global_variables();
 549 
 550   // Executes Shutdown.shutdown()
 551   void invoke_shutdown_hooks();
 552 
 553   // Cleanup on thread exit
 554   enum ExitType {
 555     normal_exit,
 556     jni_detach
 557   };
 558   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 559 
 560   void cleanup_failed_attach_current_thread(bool is_daemon);
 561 
 562   // Testers
 563   virtual bool is_Java_thread() const            { return true;  }
 564   virtual bool can_call_java() const             { return true; }
 565 
 566   virtual bool is_active_Java_thread() const;
 567 
 568   // Thread oop. threadObj() can be null for initial JavaThread
 569   // (or for threads attached via JNI)
 570   oop threadObj() const;
 571   void set_threadOopHandles(oop p);
 572   oop vthread() const;
 573   void set_vthread(oop p);
 574   oop scopedValueCache() const;
 575   void set_scopedValueCache(oop p);
 576   void clear_scopedValueBindings();
 577   oop jvmti_vthread() const;
 578   void set_jvmti_vthread(oop p);
 579   oop vthread_or_thread() const;
 580 
 581   // Prepare thread and add to priority queue.  If a priority is
 582   // not specified, use the priority of the thread object. Threads_lock
 583   // must be held while this function is called.
 584   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
 585 
 586   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
 587   address saved_exception_pc()                   { return _saved_exception_pc; }
 588 
 589   ThreadFunction entry_point() const             { return _entry_point; }
 590 
 591   // Allocates a new Java level thread object for this thread. thread_name may be null.
 592   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
 593 
 594   // Last frame anchor routines
 595 
 596   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
 597 
 598   // last_Java_sp
 599   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
 600   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
 601 
 602   // last_Java_pc
 603 
 604   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
 605 
 606   // Safepoint support
 607   inline JavaThreadState thread_state() const;
 608   inline void set_thread_state(JavaThreadState s);
 609   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
 610   inline ThreadSafepointState* safepoint_state() const;
 611   inline void set_safepoint_state(ThreadSafepointState* state);
 612   inline bool is_at_poll_safepoint();
 613 
 614   // JavaThread termination and lifecycle support:
 615   void smr_delete();
 616   bool on_thread_list() const { return _on_thread_list; }
 617   void set_on_thread_list() { _on_thread_list = true; }
 618 
 619   // thread has called JavaThread::exit(), thread's GC barrier is detached
 620   // or thread is terminated
 621   bool is_exiting() const;
 622   // thread's GC barrier is NOT detached and thread is NOT terminated
 623   bool is_oop_safe() const;
 624   // thread is terminated (no longer on the threads list); the thread must
 625   // be protected by a ThreadsListHandle to avoid potential crashes.
 626   bool check_is_terminated(TerminatedTypes l_terminated) const {
 627     return l_terminated == _thread_terminated || l_terminated == _vm_exited;
 628   }
 629   bool is_terminated() const;
 630   void set_terminated(TerminatedTypes t);
 631 
 632   void block_if_vm_exited();
 633 
 634   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
 635   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
 636 
 637   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
 638   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
 639 
 640   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
 641 
 642   static ByteSize polling_word_offset() {
 643     ByteSize offset = byte_offset_of(Thread, _poll_data) +
 644                       byte_offset_of(SafepointMechanism::ThreadData, _polling_word);
 645     // At least on x86_64, safepoint polls encode the offset as disp8 imm.
 646     assert(in_bytes(offset) < 128, "Offset >= 128");
 647     return offset;
 648   }
 649 
 650   static ByteSize polling_page_offset() {
 651     ByteSize offset = byte_offset_of(Thread, _poll_data) +
 652                       byte_offset_of(SafepointMechanism::ThreadData, _polling_page);
 653     // At least on x86_64, safepoint polls encode the offset as disp8 imm.
 654     assert(in_bytes(offset) < 128, "Offset >= 128");
 655     return offset;
 656   }
 657 
 658   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
 659 
 660   // Continuation support
 661   ContinuationEntry* last_continuation() const { return _cont_entry; }
 662   void set_cont_fastpath(intptr_t* x)          { _cont_fastpath = x; }
 663   void push_cont_fastpath(intptr_t* sp)        { if (sp > _cont_fastpath) _cont_fastpath = sp; }
 664   void set_cont_fastpath_thread_state(bool x)  { _cont_fastpath_thread_state = (int)x; }
 665   intptr_t* raw_cont_fastpath() const          { return _cont_fastpath; }
 666   bool cont_fastpath() const                   { return _cont_fastpath == nullptr && _cont_fastpath_thread_state != 0; }
 667   bool cont_fastpath_thread_state() const      { return _cont_fastpath_thread_state != 0; }
 668 
 669   void inc_held_monitor_count(intx i = 1, bool jni = false);
 670   void dec_held_monitor_count(intx i = 1, bool jni = false);
 671 
 672   intx held_monitor_count() { return _held_monitor_count; }
 673   intx jni_monitor_count()  { return _jni_monitor_count;  }
 674   void clear_jni_monitor_count() { _jni_monitor_count = 0; }
 675 
 676   // Support for SharedRuntime::monitor_exit_helper()
 677   ObjectMonitor* unlocked_inflated_monitor() const { return _unlocked_inflated_monitor; }
 678   void clear_unlocked_inflated_monitor() {
 679     _unlocked_inflated_monitor = nullptr;
 680   }
 681 
 682   inline bool is_vthread_mounted() const;
 683   inline const ContinuationEntry* vthread_continuation() const;
 684 
 685  private:
 686   DEBUG_ONLY(void verify_frame_info();)
 687 
 688   // Support for thread handshake operations
 689   HandshakeState _handshake;
 690  public:
 691   HandshakeState* handshake_state() { return &_handshake; }
 692 
 693   // A JavaThread can always safely operate on it self and other threads
 694   // can do it safely if they are the active handshaker.
 695   bool is_handshake_safe_for(Thread* th) const {
 696     return _handshake.active_handshaker() == th || this == th;
 697   }
 698 
 699   // Suspend/resume support for JavaThread
 700   // higher-level suspension/resume logic called by the public APIs
 701   bool java_suspend();
 702   bool java_resume();
 703   bool is_suspended()     { return _handshake.is_suspended(); }
 704 
 705   // Check for async exception in addition to safepoint.
 706   static void check_special_condition_for_native_trans(JavaThread *thread);
 707 
 708   // Synchronize with another thread that is deoptimizing objects of the
 709   // current thread, i.e. reverts optimizations based on escape analysis.
 710   void wait_for_object_deoptimization();
 711 
 712 #if INCLUDE_JVMTI
 713   inline void set_carrier_thread_suspended();
 714   inline void clear_carrier_thread_suspended();
 715 
 716   bool is_carrier_thread_suspended() const {
 717     return _carrier_thread_suspended;
 718   }
 719 
 720   bool is_in_VTMS_transition() const             { return _is_in_VTMS_transition; }
 721   bool is_in_tmp_VTMS_transition() const         { return _is_in_tmp_VTMS_transition; }
 722   bool is_in_any_VTMS_transition() const         { return _is_in_VTMS_transition || _is_in_tmp_VTMS_transition; }
 723 
 724   void set_is_in_VTMS_transition(bool val);
 725   void toggle_is_in_tmp_VTMS_transition()        { _is_in_tmp_VTMS_transition = !_is_in_tmp_VTMS_transition; };
 726 
 727   bool is_disable_suspend() const                { return _is_disable_suspend; }
 728   void toggle_is_disable_suspend()               { _is_disable_suspend = !_is_disable_suspend; };
 729 
 730   bool VTMS_transition_mark() const              { return Atomic::load(&_VTMS_transition_mark); }
 731   void set_VTMS_transition_mark(bool val)        { Atomic::store(&_VTMS_transition_mark, val); }
 732 
 733   bool pending_jvmti_unmount_event()             { return _pending_jvmti_unmount_event; }
 734   void set_pending_jvmti_unmount_event(bool val) { _pending_jvmti_unmount_event = val; }
 735 
 736   bool on_monitor_waited_event()             { return _on_monitor_waited_event; }
 737   void set_on_monitor_waited_event(bool val) { _on_monitor_waited_event = val; }
 738 
 739   bool pending_contended_entered_event()         { return _contended_entered_monitor != nullptr; }
 740   ObjectMonitor* contended_entered_monitor()     { return _contended_entered_monitor; }
 741 #ifdef ASSERT
 742   bool is_VTMS_transition_disabler() const       { return _is_VTMS_transition_disabler; }
 743   void set_is_VTMS_transition_disabler(bool val);
 744 #endif
 745 #endif
 746 
 747   void set_contended_entered_monitor(ObjectMonitor* val) NOT_JVMTI_RETURN JVMTI_ONLY({ _contended_entered_monitor = val; })
 748 
 749   // Support for object deoptimization and JFR suspension
 750   void handle_special_runtime_exit_condition();
 751   bool has_special_runtime_exit_condition() {
 752     return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
 753   }
 754 
 755   // Stack-locking support (not for LM_LIGHTWEIGHT)
 756   bool is_lock_owned(address adr) const;
 757 
 758   // Accessors for vframe array top
 759   // The linked list of vframe arrays are sorted on sp. This means when we
 760   // unpack the head must contain the vframe array to unpack.
 761   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
 762   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
 763 
 764   // Side structure for deferring update of java frame locals until deopt occurs
 765   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
 766   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
 767 
 768   // These only really exist to make debugging deopt problems simpler
 769 
 770   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
 771   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
 772 
 773   // The special resourceMark used during deoptimization
 774 
 775   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
 776   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
 777 
 778   void set_deopt_compiled_method(nmethod* nm)    { _deopt_nmethod = nm; }
 779   nmethod* deopt_compiled_method()               { return _deopt_nmethod; }
 780 
 781   Method*    callee_target() const               { return _callee_target; }
 782   void set_callee_target  (Method* x)            { _callee_target   = x; }
 783 
 784   // Oop results of vm runtime calls
 785   oop  vm_result() const                         { return _vm_result; }
 786   void set_vm_result  (oop x)                    { _vm_result   = x; }
 787 
 788   void set_vm_result_2  (Metadata* x)            { _vm_result_2   = x; }
 789 
 790   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
 791   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
 792 
 793   // Is thread in scope of an InternalOOMEMark?
 794   bool is_in_internal_oome_mark() const          { return _is_in_internal_oome_mark; }
 795   void set_is_in_internal_oome_mark(bool b)      { _is_in_internal_oome_mark = b;    }
 796 
 797 #if INCLUDE_JVMCI
 798   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
 799   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
 800   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
 801   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
 802   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
 803   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == nullptr, "must be"); _jvmci._alternate_call_target = a; }
 804   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == nullptr, "must be"); _jvmci._implicit_exception_pc = a; }
 805 
 806   JVMCIRuntime* libjvmci_runtime() const          { return _libjvmci_runtime; }
 807   void set_libjvmci_runtime(JVMCIRuntime* rt) {
 808     assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
 809     _libjvmci_runtime = rt;
 810   }
 811 #endif // INCLUDE_JVMCI
 812 
 813   // Exception handling for compiled methods
 814   oop      exception_oop() const;
 815   address  exception_pc() const                  { return _exception_pc; }
 816 
 817   void set_exception_oop(oop o);
 818   void set_exception_pc(address a)               { _exception_pc = a; }
 819   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
 820   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
 821 
 822   void clear_exception_oop_and_pc() {
 823     set_exception_oop(nullptr);
 824     set_exception_pc(nullptr);
 825   }
 826 
 827   // Check if address is in the usable part of the stack (excludes protected
 828   // guard pages). Can be applied to any thread and is an approximation for
 829   // using is_in_live_stack when the query has to happen from another thread.
 830   bool is_in_usable_stack(address adr) const {
 831     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
 832   }
 833 
 834   // Misc. accessors/mutators
 835   static ByteSize scopedValueCache_offset()       { return byte_offset_of(JavaThread, _scopedValueCache); }
 836 
 837   // For assembly stub generation
 838   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
 839   static ByteSize vthread_offset()               { return byte_offset_of(JavaThread, _vthread); }
 840   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
 841   static ByteSize pending_jni_exception_check_fn_offset() {
 842     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
 843   }
 844   static ByteSize last_Java_sp_offset() {
 845     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
 846   }
 847   static ByteSize last_Java_pc_offset() {
 848     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
 849   }
 850   static ByteSize frame_anchor_offset() {
 851     return byte_offset_of(JavaThread, _anchor);
 852   }
 853   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
 854   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
 855   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
 856   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
 857   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
 858   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
 859 #if INCLUDE_JVMCI
 860   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
 861   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
 862   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
 863   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
 864   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
 865 #endif // INCLUDE_JVMCI
 866   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
 867   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
 868   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
 869   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
 870 
 871   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
 872 
 873   // StackOverflow offsets
 874   static ByteSize stack_overflow_limit_offset()  {
 875     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
 876   }
 877   static ByteSize stack_guard_state_offset()     {
 878     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
 879   }
 880   static ByteSize reserved_stack_activation_offset() {
 881     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
 882   }
 883   static ByteSize shadow_zone_safe_limit()  {
 884     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
 885   }
 886   static ByteSize shadow_zone_growth_watermark()  {
 887     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
 888   }
 889 
 890   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
 891 
 892   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
 893   static ByteSize should_post_on_exceptions_flag_offset() {
 894     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
 895   }
 896   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
 897   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
 898 
 899   static ByteSize lock_id_offset()            { return byte_offset_of(JavaThread, _lock_id); }
 900 
 901   static ByteSize cont_entry_offset()         { return byte_offset_of(JavaThread, _cont_entry); }
 902   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
 903   static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
 904   static ByteSize jni_monitor_count_offset()  { return byte_offset_of(JavaThread, _jni_monitor_count); }
 905   static ByteSize preemption_cancelled_offset()  { return byte_offset_of(JavaThread, _preemption_cancelled); }
 906   static ByteSize preempt_alternate_return_offset() { return byte_offset_of(JavaThread, _preempt_alternate_return); }
 907   static ByteSize unlocked_inflated_monitor_offset() { return byte_offset_of(JavaThread, _unlocked_inflated_monitor); }
 908 
 909 #if INCLUDE_JVMTI
 910   static ByteSize is_in_VTMS_transition_offset()     { return byte_offset_of(JavaThread, _is_in_VTMS_transition); }
 911   static ByteSize is_in_tmp_VTMS_transition_offset() { return byte_offset_of(JavaThread, _is_in_tmp_VTMS_transition); }
 912   static ByteSize is_disable_suspend_offset()        { return byte_offset_of(JavaThread, _is_disable_suspend); }
 913 #endif
 914 
 915   // Returns the jni environment for this thread
 916   JNIEnv* jni_environment()                      { return &_jni_environment; }
 917 
 918   // Returns the current thread as indicated by the given JNIEnv.
 919   // We don't assert it is Thread::current here as that is done at the
 920   // external JNI entry points where the JNIEnv is passed into the VM.
 921   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
 922     JavaThread* current = reinterpret_cast<JavaThread*>(((intptr_t)env - in_bytes(jni_environment_offset())));
 923     // We can't normally get here in a thread that has completed its
 924     // execution and so "is_terminated", except when the call is from
 925     // AsyncGetCallTrace, which can be triggered by a signal at any point in
 926     // a thread's lifecycle. A thread is also considered terminated if the VM
 927     // has exited, so we have to check this and block in case this is a daemon
 928     // thread returning to the VM (the JNI DirectBuffer entry points rely on
 929     // this).
 930     if (current->is_terminated()) {
 931       current->block_if_vm_exited();
 932     }
 933     return current;
 934   }
 935 
 936   // JNI critical regions. These can nest.
 937   bool in_critical()    { return _jni_active_critical > 0; }
 938   bool in_last_critical()  { return _jni_active_critical == 1; }
 939   inline void enter_critical();
 940   void exit_critical() {
 941     assert(Thread::current() == this, "this must be current thread");
 942     _jni_active_critical--;
 943     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
 944   }
 945 
 946   // Checked JNI: is the programmer required to check for exceptions, if so specify
 947   // which function name. Returning to a Java frame should implicitly clear the
 948   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
 949   // VM->Java transitions are not cleared, it is expected that JNI code enclosed
 950   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
 951   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != nullptr; }
 952   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = nullptr; }
 953   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
 954   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
 955 
 956   // For deadlock detection
 957   int depth_first_number() { return _depth_first_number; }
 958   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
 959 
 960  public:
 961   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
 962   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
 963   void dec_in_deopt_handler() {
 964     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
 965     if (_in_deopt_handler > 0) { // robustness
 966       _in_deopt_handler--;
 967     }
 968   }
 969 
 970  private:
 971   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
 972 
 973   // factor out low-level mechanics for use in both normal and error cases
 974   const char* get_thread_name_string(char* buf = nullptr, int buflen = 0) const;
 975 
 976  public:
 977 
 978   // Frame iteration; calls the function f for all frames on the stack
 979   void frames_do(void f(frame*, const RegisterMap*));
 980 
 981   // Memory operations
 982   void oops_do_frames(OopClosure* f, NMethodClosure* cf);
 983   void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
 984 
 985   // GC operations
 986   virtual void nmethods_do(NMethodClosure* cf);
 987 
 988   // RedefineClasses Support
 989   void metadata_do(MetadataClosure* f);
 990 
 991   // Debug method asserting thread states are correct during a handshake operation.
 992   DEBUG_ONLY(void verify_states_for_handshake();)
 993 
 994   // Misc. operations
 995   const char* name() const;
 996   const char* name_raw() const;
 997   const char* type_name() const { return "JavaThread"; }
 998   static const char* name_for(oop thread_obj);
 999 
1000   void print_on(outputStream* st, bool print_extended_info) const;
1001   void print_on(outputStream* st) const { print_on(st, false); }
1002   void print() const;
1003   void print_thread_state_on(outputStream*) const;
1004   void print_on_error(outputStream* st, char* buf, int buflen) const;
1005   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1006   void verify();
1007 
1008   // Accessing frames
1009   frame last_frame() {
1010     _anchor.make_walkable();
1011     return pd_last_frame();
1012   }
1013   javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
1014 
1015   frame carrier_last_frame(RegisterMap* reg_map);
1016   javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
1017 
1018   frame vthread_last_frame();
1019   javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
1020 
1021   frame platform_thread_last_frame(RegisterMap* reg_map);
1022   javaVFrame*  platform_thread_last_java_vframe(RegisterMap* reg_map) {
1023     return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
1024   }
1025 
1026   javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
1027 
1028   // Returns method at 'depth' java or native frames down the stack
1029   // Used for security checks
1030   Klass* security_get_caller_class(int depth);
1031 
1032   // Print stack trace in external format
1033   // These variants print carrier/platform thread information only.
1034   void print_stack_on(outputStream* st);
1035   void print_stack() { print_stack_on(tty); }
1036   // This prints the currently mounted virtual thread.
1037   void print_vthread_stack_on(outputStream* st);
1038   // This prints the active stack: either carrier/platform or virtual.
1039   void print_active_stack_on(outputStream* st);
1040   // Print current stack trace for checked JNI warnings and JNI fatal errors.
1041   // This is the external format from above, but selecting the platform
1042   // or vthread as applicable.
1043   void print_jni_stack();
1044 
1045   // Print stack traces in various internal formats
1046   void trace_stack()                             PRODUCT_RETURN;
1047   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1048   void trace_frames()                            PRODUCT_RETURN;
1049 
1050   // Print an annotated view of the stack frames
1051   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1052   void validate_frame_layout() {
1053     print_frame_layout(0, true);
1054   }
1055 
1056   // Function for testing deoptimization
1057   void deoptimize();
1058   void make_zombies();
1059 
1060   void deoptimize_marked_methods();
1061 
1062  public:
1063   // Returns the running thread as a JavaThread
1064   static JavaThread* current() {
1065     return JavaThread::cast(Thread::current());
1066   }
1067 
1068   // Returns the current thread as a JavaThread, or nullptr if not attached
1069   static inline JavaThread* current_or_null();
1070 
1071   // Casts
1072   static JavaThread* cast(Thread* t) {
1073     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1074     return static_cast<JavaThread*>(t);
1075   }
1076 
1077   static const JavaThread* cast(const Thread* t) {
1078     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1079     return static_cast<const JavaThread*>(t);
1080   }
1081 
1082   // Returns the active Java thread.  Do not use this if you know you are calling
1083   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1084   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1085   // operation.  You may not want that either.
1086   static JavaThread* active();
1087 
1088  protected:
1089   virtual void pre_run();
1090   virtual void run();
1091   void thread_main_inner();
1092   virtual void post_run();
1093 
1094  public:
1095   // Thread local information maintained by JVMTI.
1096   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1097   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1098   // getter is used to get this JavaThread's JvmtiThreadState if it has
1099   // one which means null can be returned. JvmtiThreadState::state_for()
1100   // is used to get the specified JavaThread's JvmtiThreadState if it has
1101   // one or it allocates a new JvmtiThreadState for the JavaThread and
1102   // returns it. JvmtiThreadState::state_for() will return null only if
1103   // the specified JavaThread is exiting.
1104   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1105   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1106 
1107 #if INCLUDE_JVMTI
1108   // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1109   JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1110 #endif
1111 
1112   // JVMTI PopFrame support
1113   // Setting and clearing popframe_condition
1114   // All of these enumerated values are bits. popframe_pending
1115   // indicates that a PopFrame() has been requested and not yet been
1116   // completed. popframe_processing indicates that that PopFrame() is in
1117   // the process of being completed. popframe_force_deopt_reexecution_bit
1118   // indicates that special handling is required when returning to a
1119   // deoptimized caller.
1120   enum PopCondition {
1121     popframe_inactive                      = 0x00,
1122     popframe_pending_bit                   = 0x01,
1123     popframe_processing_bit                = 0x02,
1124     popframe_force_deopt_reexecution_bit   = 0x04
1125   };
1126   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1127   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1128   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1129   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1130   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1131   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1132   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1133 
1134   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1135   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1136   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1137 
1138   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1139   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1140   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1141 
1142  private:
1143   // Saved incoming arguments to popped frame.
1144   // Used only when popped interpreted frame returns to deoptimized frame.
1145   void*    _popframe_preserved_args;
1146   int      _popframe_preserved_args_size;
1147 
1148  public:
1149   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1150   void* popframe_preserved_args();
1151   ByteSize popframe_preserved_args_size();
1152   WordSize popframe_preserved_args_size_in_words();
1153   void  popframe_free_preserved_args();
1154 
1155 
1156  private:
1157   JvmtiThreadState *_jvmti_thread_state;
1158 
1159   // Used by the interpreter in fullspeed mode for frame pop, method
1160   // entry, method exit and single stepping support. This field is
1161   // only set to non-zero at a safepoint or using a direct handshake
1162   // (see EnterInterpOnlyModeClosure).
1163   // It can be set to zero asynchronously to this threads execution (i.e., without
1164   // safepoint/handshake or a lock) so we have to be very careful.
1165   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1166   int               _interp_only_mode;
1167 
1168  public:
1169   // used by the interpreter for fullspeed debugging support (see above)
1170   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1171   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1172   int get_interp_only_mode()                { return _interp_only_mode; }
1173   int set_interp_only_mode(int val)         { return _interp_only_mode = val; }
1174   void increment_interp_only_mode()         { ++_interp_only_mode; }
1175   void decrement_interp_only_mode()         { --_interp_only_mode; }
1176 
1177   // support for cached flag that indicates whether exceptions need to be posted for this thread
1178   // if this is false, we can avoid deoptimizing when events are thrown
1179   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1180  private:
1181   int    _should_post_on_exceptions_flag;
1182 
1183  public:
1184   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1185 
1186  private:
1187   ThreadStatistics *_thread_stat;
1188 
1189  public:
1190   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1191 
1192   // Return a blocker object for which this thread is blocked parking.
1193   oop current_park_blocker();
1194 
1195  private:
1196   static size_t _stack_size_at_create;
1197 
1198  public:
1199   static inline size_t stack_size_at_create(void) {
1200     return _stack_size_at_create;
1201   }
1202   static inline void set_stack_size_at_create(size_t value) {
1203     _stack_size_at_create = value;
1204   }
1205 
1206   // Machine dependent stuff
1207 #include OS_CPU_HEADER(javaThread)
1208 
1209   // JSR166 per-thread parker
1210  private:
1211   Parker _parker;
1212  public:
1213   Parker* parker() { return &_parker; }
1214 
1215  public:
1216   // clearing/querying jni attach status
1217   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1218   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1219   inline void set_done_attaching_via_jni();
1220 
1221   // Stack dump assistance:
1222   // Track the class we want to initialize but for which we have to wait
1223   // on its init_lock() because it is already being initialized.
1224   void set_class_to_be_initialized(InstanceKlass* k);
1225   InstanceKlass* class_to_be_initialized() const;
1226 
1227   // Track executing class initializer, see ThreadInClassInitializer
1228   void set_class_being_initialized(InstanceKlass* k);
1229   InstanceKlass* class_being_initialized() const;
1230 
1231 private:
1232   InstanceKlass* _class_to_be_initialized;
1233   InstanceKlass* _class_being_initialized;
1234 
1235   // java.lang.Thread.sleep support
1236   ParkEvent * _SleepEvent;
1237 
1238 #if INCLUDE_JFR
1239   // Support for jdk.VirtualThreadPinned event
1240   Ticks _pinned_start_time;
1241 #endif
1242 
1243 public:
1244   bool sleep(jlong millis);
1245   bool sleep_nanos(jlong nanos);
1246 
1247   // java.lang.Thread interruption support
1248   void interrupt();
1249   bool is_interrupted(bool clear_interrupted);
1250 
1251 #if INCLUDE_JFR
1252   Ticks& vthread_pinned_start_time() { return _pinned_start_time; }
1253   void start_vthread_pinned() { _pinned_start_time = Ticks::now(); }
1254   void post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* reason);
1255 #endif
1256 
1257   // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
1258   // the Java code in Object::wait which are not present in RawMonitorWait.
1259   bool get_and_clear_interrupted();
1260 
1261 private:
1262   LockStack _lock_stack;
1263   OMCache _om_cache;
1264 
1265 public:
1266   LockStack& lock_stack() { return _lock_stack; }
1267 
1268   static ByteSize lock_stack_offset()      { return byte_offset_of(JavaThread, _lock_stack); }
1269   // Those offsets are used in code generators to access the LockStack that is embedded in this
1270   // JavaThread structure. Those accesses are relative to the current thread, which
1271   // is typically in a dedicated register.
1272   static ByteSize lock_stack_top_offset()  { return lock_stack_offset() + LockStack::top_offset(); }
1273   static ByteSize lock_stack_base_offset() { return lock_stack_offset() + LockStack::base_offset(); }
1274 
1275   static ByteSize om_cache_offset()        { return byte_offset_of(JavaThread, _om_cache); }
1276   static ByteSize om_cache_oops_offset()   { return om_cache_offset() + OMCache::entries_offset(); }
1277 
1278   void om_set_monitor_cache(ObjectMonitor* monitor);
1279   void om_clear_monitor_cache();
1280   ObjectMonitor* om_get_from_monitor_cache(oop obj);
1281 
1282   static OopStorage* thread_oop_storage();
1283 
1284   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1285 
1286   // Helper function to create the java.lang.Thread object for a
1287   // VM-internal thread. The thread will have the given name and be
1288   // part of the System ThreadGroup.
1289   static Handle create_system_thread_object(const char* name, TRAPS);
1290 
1291   // Helper function to start a VM-internal daemon thread.
1292   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1293   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1294                                     Handle thread_oop, ThreadPriority prio);
1295 
1296   // Helper function to do vm_exit_on_initialization for osthread
1297   // resource allocation failure.
1298   static void vm_exit_on_osthread_failure(JavaThread* thread);
1299 
1300   // Deferred OopHandle release support
1301  private:
1302   // List of OopHandles to be released - guarded by the Service_lock.
1303   static OopHandleList* _oop_handle_list;
1304   // Add our OopHandles to the list for the service thread to release.
1305   void add_oop_handles_for_release();
1306   // Called by the ServiceThread to release the OopHandles.
1307   static void release_oop_handles();
1308   // Called by the ServiceThread to poll if there are any OopHandles to release.
1309   // Called when holding the Service_lock.
1310   static bool has_oop_handles_to_release() {
1311     return _oop_handle_list != nullptr;
1312   }
1313 };
1314 
1315 inline JavaThread* JavaThread::current_or_null() {
1316   Thread* current = Thread::current_or_null();
1317   return current != nullptr ? JavaThread::cast(current) : nullptr;
1318 }
1319 
1320 class UnlockFlagSaver {
1321   private:
1322     JavaThread* _thread;
1323     bool _do_not_unlock;
1324   public:
1325     UnlockFlagSaver(JavaThread* t) {
1326       _thread = t;
1327       _do_not_unlock = t->do_not_unlock_if_synchronized();
1328       t->set_do_not_unlock_if_synchronized(false);
1329     }
1330     ~UnlockFlagSaver() {
1331       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1332     }
1333 };
1334 
1335 class JNIHandleMark : public StackObj {
1336   JavaThread* _thread;
1337  public:
1338   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1339     thread->push_jni_handle_block();
1340   }
1341   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1342 };
1343 
1344 class NoPreemptMark {
1345   ContinuationEntry* _ce;
1346   bool _unpin;
1347  public:
1348   NoPreemptMark(JavaThread* thread) : _ce(thread->last_continuation()), _unpin(false) {
1349     if (_ce != nullptr) _unpin = _ce->pin();
1350   }
1351   ~NoPreemptMark() { if (_unpin) _ce->unpin(); }
1352 };
1353 
1354 class ThreadOnMonitorWaitedEvent {
1355   JavaThread* _thread;
1356  public:
1357   ThreadOnMonitorWaitedEvent(JavaThread* thread) : _thread(thread) {
1358     JVMTI_ONLY(_thread->set_on_monitor_waited_event(true);)
1359   }
1360   ~ThreadOnMonitorWaitedEvent() { JVMTI_ONLY(_thread->set_on_monitor_waited_event(false);) }
1361 };
1362 
1363 class ThreadInClassInitializer : public StackObj {
1364   InstanceKlass* _previous;
1365  public:
1366   ThreadInClassInitializer(InstanceKlass* ik) {
1367     JavaThread* current = JavaThread::current();
1368     _previous = current->class_being_initialized();
1369     current->set_class_being_initialized(ik);
1370   }
1371   ~ThreadInClassInitializer() {
1372     JavaThread* current = JavaThread::current();
1373     current->set_class_being_initialized(_previous);
1374   }
1375 };
1376 
1377 #endif // SHARE_RUNTIME_JAVATHREAD_HPP