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 "runtime/safepointMechanism.hpp"
  41 #include "runtime/stackWatermarkSet.hpp"
  42 #include "runtime/stackOverflow.hpp"
  43 #include "runtime/thread.hpp"
  44 #include "runtime/threadHeapSampler.hpp"
  45 #include "runtime/threadIdentifier.hpp"
  46 #include "runtime/threadStatisticalInfo.hpp"
  47 #include "utilities/exceptions.hpp"
  48 #include "utilities/globalDefinitions.hpp"
  49 #include "utilities/macros.hpp"
  50 #if INCLUDE_JFR
  51 #include "jfr/support/jfrThreadExtension.hpp"
  52 #include "utilities/ticks.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.
 169   int64_t _monitor_owner_id;
 170 
 171  public:
 172   void set_monitor_owner_id(int64_t id) {
 173     ThreadIdentifier::verify_id(id);
 174     _monitor_owner_id = id;
 175   }
 176   int64_t monitor_owner_id() const {
 177     int64_t id = _monitor_owner_id;
 178     ThreadIdentifier::verify_id(id);
 179     return id;
 180   }
 181 
 182   // For tracking the heavyweight monitor the thread is pending on.
 183   ObjectMonitor* current_pending_monitor() {
 184     // Use Atomic::load() to prevent data race between concurrent modification and
 185     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 186     // Especially, reloading pointer from thread after null check must be prevented.
 187     return Atomic::load(&_current_pending_monitor);
 188   }
 189   void set_current_pending_monitor(ObjectMonitor* monitor) {
 190     Atomic::store(&_current_pending_monitor, monitor);
 191   }
 192   void set_current_pending_monitor_is_from_java(bool from_java) {
 193     _current_pending_monitor_is_from_java = from_java;
 194   }
 195   bool current_pending_monitor_is_from_java() {
 196     return _current_pending_monitor_is_from_java;
 197   }
 198   ObjectMonitor* current_waiting_monitor() {
 199     // See the comment in current_pending_monitor() above.
 200     return Atomic::load(&_current_waiting_monitor);
 201   }
 202   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 203     Atomic::store(&_current_waiting_monitor, monitor);
 204   }
 205 
 206   // JNI handle support
 207   JNIHandleBlock* active_handles() const         { return _active_handles; }
 208   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 209   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 210   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 211 
 212   void push_jni_handle_block();
 213   void pop_jni_handle_block();
 214 
 215  private:
 216   enum SuspendFlags {
 217     // NOTE: avoid using the sign-bit as cc generates different test code
 218     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 219     _trace_flag             = 0x00000004U, // call tracing backend
 220     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 221   };
 222 
 223   // various suspension related flags - atomically updated
 224   volatile uint32_t _suspend_flags;
 225 
 226   inline void set_suspend_flag(SuspendFlags f);
 227   inline void clear_suspend_flag(SuspendFlags f);
 228 
 229  public:
 230   inline void set_trace_flag();
 231   inline void clear_trace_flag();
 232   inline void set_obj_deopt_flag();
 233   inline void clear_obj_deopt_flag();
 234   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 235   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 236 
 237   // Asynchronous exception support
 238  private:
 239   friend class InstallAsyncExceptionHandshake;
 240   friend class AsyncExceptionHandshake;
 241   friend class HandshakeState;
 242 
 243   void handle_async_exception(oop java_throwable);
 244  public:
 245   void install_async_exception(AsyncExceptionHandshake* aec = nullptr);
 246   bool has_async_exception_condition();
 247   inline void set_pending_unsafe_access_error();
 248   static void send_async_exception(JavaThread* jt, oop java_throwable);
 249 
 250   class NoAsyncExceptionDeliveryMark : public StackObj {
 251     friend JavaThread;
 252     JavaThread *_target;
 253     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 254     inline ~NoAsyncExceptionDeliveryMark();
 255   };
 256 
 257   // Safepoint support
 258  public:                                                        // Expose _thread_state for SafeFetchInt()
 259   volatile JavaThreadState _thread_state;
 260   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 261   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 262   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 263 #ifdef ASSERT
 264   // Debug support for checking if code allows safepoints or not.
 265   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 266   // mutex, or blocking on an object synchronizer (Java locking).
 267   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 268   // the above cases. The class NoSafepointVerifier is used to set this counter.
 269   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 270 
 271  public:
 272   void inc_no_safepoint_count() { _no_safepoint_count++; }
 273   void dec_no_safepoint_count() { _no_safepoint_count--; }
 274   bool is_in_no_safepoint_scope() { return _no_safepoint_count > 0; }
 275 #endif // ASSERT
 276  public:
 277   // These functions check conditions before possibly going to a safepoint.
 278   // including NoSafepointVerifier.
 279   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 280   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 281 
 282 #ifdef ASSERT
 283  private:
 284   volatile uint64_t _visited_for_critical_count;
 285 
 286  public:
 287   void set_visited_for_critical_count(uint64_t safepoint_id) {
 288     assert(_visited_for_critical_count == 0, "Must be reset before set");
 289     assert((safepoint_id & 0x1) == 1, "Must be odd");
 290     _visited_for_critical_count = safepoint_id;
 291   }
 292   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 293     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 294     _visited_for_critical_count = 0;
 295   }
 296   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 297     return _visited_for_critical_count == safepoint_id;
 298   }
 299 #endif // ASSERT
 300 
 301   // JavaThread termination support
 302  public:
 303   enum TerminatedTypes {
 304     _not_terminated = 0xDEAD - 3,
 305     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 306     _thread_gc_barrier_detached,                 // thread's GC barrier has been detached
 307     _thread_terminated,                          // JavaThread is removed from thread list
 308     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 309                                                  // only VM_Exit can set _vm_exited
 310   };
 311 
 312  private:
 313   // In general a JavaThread's _terminated field transitions as follows:
 314   //
 315   //   _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
 316   //
 317   // _vm_exited is a special value to cover the case of a JavaThread
 318   // executing native code after the VM itself is terminated.
 319   //
 320   // A JavaThread that fails to JNI attach has these _terminated field transitions:
 321   //   _not_terminated => _thread_terminated
 322   //
 323   volatile TerminatedTypes _terminated;
 324 
 325   jint                  _in_deopt_handler;       // count of deoptimization
 326                                                  // handlers thread is in
 327   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 328   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 329                                                          // never locked) when throwing an exception. Used by interpreter only.
 330 #if INCLUDE_JVMTI
 331   volatile bool         _carrier_thread_suspended;       // Carrier thread is externally suspended
 332   bool                  _is_in_VTMS_transition;          // thread is in 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                  _on_monitor_waited_event;        // Avoid callee arg processing for enterSpecial when posting waited event
 336   ObjectMonitor*        _contended_entered_monitor;      // Monitor for pending monitor_contended_entered callback
 337 #ifdef ASSERT
 338   bool                  _is_VTMS_transition_disabler;    // thread currently disabled VTMS transitions
 339 #endif
 340 #endif
 341 
 342   // JNI attach states:
 343   enum JNIAttachStates {
 344     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 345     _attaching_via_jni,          // thread is attaching via JNI
 346     _attached_via_jni            // thread has attached via JNI
 347   };
 348 
 349   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 350   // A native thread that is attaching via JNI starts with a value
 351   // of _attaching_via_jni and transitions to _attached_via_jni.
 352   volatile JNIAttachStates _jni_attach_state;
 353 
 354   // In scope of an InternalOOMEMark?
 355   bool _is_in_internal_oome_mark;
 356 
 357 #if INCLUDE_JVMCI
 358   // The _pending_* fields below are used to communicate extra information
 359   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 360 
 361   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 362   int       _pending_deoptimization;
 363 
 364   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 365   // before the monitor has been acquired.
 366   bool      _pending_monitorenter;
 367 
 368   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 369   bool      _pending_transfer_to_interpreter;
 370 
 371   // An id of a speculation that JVMCI compiled code can use to further describe and
 372   // uniquely identify the speculative optimization guarded by an uncommon trap.
 373   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 374   jlong     _pending_failed_speculation;
 375 
 376   // These fields are mutually exclusive in terms of live ranges.
 377   union {
 378     // Communicates the pc at which the most recent implicit exception occurred
 379     // from the signal handler to a deoptimization stub.
 380     address   _implicit_exception_pc;
 381 
 382     // Communicates an alternative call target to an i2c stub from a JavaCall .
 383     address   _alternate_call_target;
 384   } _jvmci;
 385 
 386   // The JVMCIRuntime in a JVMCI shared library
 387   JVMCIRuntime* _libjvmci_runtime;
 388 
 389   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 390   jlong*    _jvmci_counters;
 391 
 392   // Fast thread locals for use by JVMCI
 393   jlong      _jvmci_reserved0;
 394   jlong      _jvmci_reserved1;
 395   oop        _jvmci_reserved_oop0;
 396 
 397   // This field is used to keep an nmethod visible to the GC so that it and its contained oops can
 398   // be kept alive
 399   nmethod*  _live_nmethod;
 400 
 401  public:
 402   static jlong* _jvmci_old_thread_counters;
 403   static void collect_counters(jlong* array, int length);
 404 
 405   bool resize_counters(int current_size, int new_size);
 406 
 407   static bool resize_all_jvmci_counters(int new_size);
 408 
 409   void set_jvmci_reserved_oop0(oop value) {
 410     _jvmci_reserved_oop0 = value;
 411   }
 412 
 413   oop get_jvmci_reserved_oop0() {
 414     return _jvmci_reserved_oop0;
 415   }
 416 
 417   void set_jvmci_reserved0(jlong value) {
 418     _jvmci_reserved0 = value;
 419   }
 420 
 421   jlong get_jvmci_reserved0() {
 422     return _jvmci_reserved0;
 423   }
 424 
 425   void set_jvmci_reserved1(jlong value) {
 426     _jvmci_reserved1 = value;
 427   }
 428 
 429   jlong get_jvmci_reserved1() {
 430     return _jvmci_reserved1;
 431   }
 432 
 433   void set_live_nmethod(nmethod* nm) {
 434     assert(_live_nmethod == nullptr, "only one");
 435     _live_nmethod = nm;
 436   }
 437 
 438   void clear_live_nmethod() {
 439     _live_nmethod = nullptr;
 440   }
 441 
 442  private:
 443 #endif // INCLUDE_JVMCI
 444 
 445   StackOverflow    _stack_overflow_state;
 446 
 447   void pretouch_stack();
 448 
 449   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 450   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 451   // code)
 452   volatile oop     _exception_oop;               // Exception thrown in compiled code
 453   volatile address _exception_pc;                // PC where exception happened
 454   volatile address _exception_handler_pc;        // PC for handler of exception
 455   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 456 
 457  private:
 458   // support for JNI critical regions
 459   jint    _jni_active_critical;                  // count of entries into JNI critical region
 460 
 461   // Checked JNI: function name requires exception check
 462   char* _pending_jni_exception_check_fn;
 463 
 464   // For deadlock detection.
 465   int _depth_first_number;
 466 
 467   // JVMTI PopFrame support
 468   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 469   int _popframe_condition;
 470 
 471   // If reallocation of scalar replaced objects fails, we throw OOM
 472   // and during exception propagation, pop the top
 473   // _frames_to_pop_failed_realloc frames, the ones that reference
 474   // failed reallocations.
 475   int _frames_to_pop_failed_realloc;
 476 
 477   ContinuationEntry* _cont_entry;
 478   intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub/upcall_stub/native_wrapper
 479                             // frame inside the continuation that we know about
 480   int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
 481 
 482   // It's signed for error detection.
 483   intx _held_monitor_count;  // used by continuations for fast lock detection
 484   intx _jni_monitor_count;
 485   ObjectMonitor* _unlocked_inflated_monitor;
 486 
 487   bool _can_call_java;
 488 
 489   // This is the field we poke in the interpreter and native
 490   // wrapper (Object.wait) to check for preemption.
 491   address _preempt_alternate_return;
 492   // When preempting on monitorenter we could have acquired the
 493   // monitor after freezing all vthread frames. In that case we
 494   // set this field so that in the preempt stub we call thaw again
 495   // instead of unmounting.
 496   bool _preemption_cancelled;
 497   // For Object.wait() we set this field to know if we need to
 498   // throw IE at the end of thawing before returning to Java.
 499   bool _pending_interrupted_exception;
 500 
 501  public:
 502   bool preemption_cancelled()           { return _preemption_cancelled; }
 503   void set_preemption_cancelled(bool b) { _preemption_cancelled = b; }
 504 
 505   bool pending_interrupted_exception()           { return _pending_interrupted_exception; }
 506   void set_pending_interrupted_exception(bool b) { _pending_interrupted_exception = b; }
 507 
 508   bool preempting()           { return _preempt_alternate_return != nullptr; }
 509   void set_preempt_alternate_return(address val) { _preempt_alternate_return = val; }
 510 
 511 private:
 512 
 513   friend class VMThread;
 514   friend class ThreadWaitTransition;
 515   friend class VM_Exit;
 516 
 517   // Stack watermark barriers.
 518   StackWatermarks _stack_watermarks;
 519 
 520  public:
 521   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
 522 
 523  public:
 524   // Constructor
 525   JavaThread(MemTag mem_tag = mtThread);   // delegating constructor
 526   JavaThread(ThreadFunction entry_point, size_t stack_size = 0, MemTag mem_tag = mtThread);
 527   ~JavaThread();
 528 
 529   // Factory method to create a new JavaThread whose attach state is "is attaching"
 530   static JavaThread* create_attaching_thread();
 531 
 532 #ifdef ASSERT
 533   // verify this JavaThread hasn't be published in the Threads::list yet
 534   void verify_not_published();
 535 #endif // ASSERT
 536 
 537   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
 538 
 539   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 540   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 541     _jni_environment.functions = functionTable;
 542   }
 543   struct JNINativeInterface_* get_jni_functions() {
 544     return (struct JNINativeInterface_ *)_jni_environment.functions;
 545   }
 546 
 547   // This function is called at thread creation to allow
 548   // platform specific thread variables to be initialized.
 549   void cache_global_variables();
 550 
 551   // Executes Shutdown.shutdown()
 552   void invoke_shutdown_hooks();
 553 
 554   // Cleanup on thread exit
 555   enum ExitType {
 556     normal_exit,
 557     jni_detach
 558   };
 559   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 560 
 561   void cleanup_failed_attach_current_thread(bool is_daemon);
 562 
 563   class NoJavaCodeMark : public StackObj {
 564     friend JavaThread;
 565     JavaThread* _target;
 566     bool _orig;
 567    public:
 568     NoJavaCodeMark(JavaThread* t) : _target(t), _orig(t->_can_call_java) {
 569       _target->_can_call_java = false;
 570     }
 571     ~NoJavaCodeMark() {
 572       _target->_can_call_java = _orig;
 573     }
 574   };
 575 
 576   // Testers
 577   virtual bool is_Java_thread() const            { return true;  }
 578   virtual bool can_call_java() const             { return _can_call_java; }
 579 
 580   virtual bool is_active_Java_thread() const;
 581 
 582   // Thread oop. threadObj() can be null for initial JavaThread
 583   // (or for threads attached via JNI)
 584   oop threadObj() const;
 585   void set_threadOopHandles(oop p);
 586   oop vthread() const;
 587   void set_vthread(oop p);
 588   oop scopedValueCache() const;
 589   void set_scopedValueCache(oop p);
 590   void clear_scopedValueBindings();
 591   oop jvmti_vthread() const;
 592   void set_jvmti_vthread(oop p);
 593   oop vthread_or_thread() const;
 594 
 595   // Prepare thread and add to priority queue.  If a priority is
 596   // not specified, use the priority of the thread object. Threads_lock
 597   // must be held while this function is called.
 598   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
 599 
 600   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
 601   address saved_exception_pc()                   { return _saved_exception_pc; }
 602 
 603   ThreadFunction entry_point() const             { return _entry_point; }
 604 
 605   // Allocates a new Java level thread object for this thread. thread_name may be null.
 606   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
 607 
 608   // Last frame anchor routines
 609 
 610   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
 611 
 612   // last_Java_sp
 613   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
 614   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
 615 
 616   // last_Java_pc
 617 
 618   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
 619 
 620   // Safepoint support
 621   inline JavaThreadState thread_state() const;
 622   inline void set_thread_state(JavaThreadState s);
 623   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
 624   inline ThreadSafepointState* safepoint_state() const;
 625   inline void set_safepoint_state(ThreadSafepointState* state);
 626   inline bool is_at_poll_safepoint();
 627 
 628   // JavaThread termination and lifecycle support:
 629   void smr_delete();
 630   bool on_thread_list() const { return _on_thread_list; }
 631   void set_on_thread_list() { _on_thread_list = true; }
 632 
 633   // thread has called JavaThread::exit(), thread's GC barrier is detached
 634   // or thread is terminated
 635   bool is_exiting() const;
 636   // thread's GC barrier is NOT detached and thread is NOT terminated
 637   bool is_oop_safe() const;
 638   // thread is terminated (no longer on the threads list); the thread must
 639   // be protected by a ThreadsListHandle to avoid potential crashes.
 640   bool check_is_terminated(TerminatedTypes l_terminated) const {
 641     return l_terminated == _thread_terminated || l_terminated == _vm_exited;
 642   }
 643   bool is_terminated() const;
 644   void set_terminated(TerminatedTypes t);
 645 
 646   void block_if_vm_exited();
 647 
 648   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
 649   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
 650 
 651   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
 652   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
 653 
 654   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
 655 
 656   static ByteSize polling_word_offset() {
 657     ByteSize offset = byte_offset_of(Thread, _poll_data) +
 658                       byte_offset_of(SafepointMechanism::ThreadData, _polling_word);
 659     // At least on x86_64, safepoint polls encode the offset as disp8 imm.
 660     assert(in_bytes(offset) < 128, "Offset >= 128");
 661     return offset;
 662   }
 663 
 664   static ByteSize polling_page_offset() {
 665     ByteSize offset = byte_offset_of(Thread, _poll_data) +
 666                       byte_offset_of(SafepointMechanism::ThreadData, _polling_page);
 667     // At least on x86_64, safepoint polls encode the offset as disp8 imm.
 668     assert(in_bytes(offset) < 128, "Offset >= 128");
 669     return offset;
 670   }
 671 
 672   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
 673 
 674   // Continuation support
 675   ContinuationEntry* last_continuation() const { return _cont_entry; }
 676   void set_cont_fastpath(intptr_t* x)          { _cont_fastpath = x; }
 677   void push_cont_fastpath(intptr_t* sp)        { if (sp > _cont_fastpath) _cont_fastpath = sp; }
 678   void set_cont_fastpath_thread_state(bool x)  { _cont_fastpath_thread_state = (int)x; }
 679   intptr_t* raw_cont_fastpath() const          { return _cont_fastpath; }
 680   bool cont_fastpath() const                   { return _cont_fastpath == nullptr && _cont_fastpath_thread_state != 0; }
 681   bool cont_fastpath_thread_state() const      { return _cont_fastpath_thread_state != 0; }
 682 
 683   void inc_held_monitor_count(intx i = 1, bool jni = false);
 684   void dec_held_monitor_count(intx i = 1, bool jni = false);
 685 
 686   intx held_monitor_count() { return _held_monitor_count; }
 687   intx jni_monitor_count()  { return _jni_monitor_count;  }
 688   void clear_jni_monitor_count() { _jni_monitor_count = 0; }
 689 
 690   // Support for SharedRuntime::monitor_exit_helper()
 691   ObjectMonitor* unlocked_inflated_monitor() const { return _unlocked_inflated_monitor; }
 692   void clear_unlocked_inflated_monitor() {
 693     _unlocked_inflated_monitor = nullptr;
 694   }
 695 
 696   inline bool is_vthread_mounted() const;
 697   inline const ContinuationEntry* vthread_continuation() const;
 698 
 699  private:
 700   DEBUG_ONLY(void verify_frame_info();)
 701 
 702   // Support for thread handshake operations
 703   HandshakeState _handshake;
 704  public:
 705   HandshakeState* handshake_state() { return &_handshake; }
 706 
 707   // A JavaThread can always safely operate on it self and other threads
 708   // can do it safely if they are the active handshaker.
 709   bool is_handshake_safe_for(Thread* th) const {
 710     return _handshake.active_handshaker() == th || this == th;
 711   }
 712 
 713   // Suspend/resume support for JavaThread
 714   // higher-level suspension/resume logic called by the public APIs
 715   bool java_suspend();
 716   bool java_resume();
 717   bool is_suspended()     { return _handshake.is_suspended(); }
 718 
 719   // Check for async exception in addition to safepoint.
 720   static void check_special_condition_for_native_trans(JavaThread *thread);
 721 
 722   // Synchronize with another thread that is deoptimizing objects of the
 723   // current thread, i.e. reverts optimizations based on escape analysis.
 724   void wait_for_object_deoptimization();
 725 
 726 #if INCLUDE_JVMTI
 727   inline void set_carrier_thread_suspended();
 728   inline void clear_carrier_thread_suspended();
 729 
 730   bool is_carrier_thread_suspended() const {
 731     return _carrier_thread_suspended;
 732   }
 733 
 734   bool is_in_VTMS_transition() const             { return _is_in_VTMS_transition; }
 735   void set_is_in_VTMS_transition(bool val);
 736 
 737   bool is_disable_suspend() const                { return _is_disable_suspend; }
 738   void toggle_is_disable_suspend()               { _is_disable_suspend = !_is_disable_suspend; };
 739 
 740   bool VTMS_transition_mark() const              { return Atomic::load(&_VTMS_transition_mark); }
 741   void set_VTMS_transition_mark(bool val)        { Atomic::store(&_VTMS_transition_mark, val); }
 742 
 743   // Temporarily skip posting JVMTI events for safety reasons when executions is in a critical section:
 744   // - is in a VTMS transition (_is_in_VTMS_transition)
 745   // - is in an interruptLock or similar critical section (_is_disable_suspend)
 746   bool should_hide_jvmti_events() const          { return _is_in_VTMS_transition || _is_disable_suspend; }
 747 
 748   bool on_monitor_waited_event()             { return _on_monitor_waited_event; }
 749   void set_on_monitor_waited_event(bool val) { _on_monitor_waited_event = val; }
 750 
 751   bool pending_contended_entered_event()         { return _contended_entered_monitor != nullptr; }
 752   ObjectMonitor* contended_entered_monitor()     { return _contended_entered_monitor; }
 753 #ifdef ASSERT
 754   bool is_VTMS_transition_disabler() const       { return _is_VTMS_transition_disabler; }
 755   void set_is_VTMS_transition_disabler(bool val);
 756 #endif
 757 #endif
 758 
 759   void set_contended_entered_monitor(ObjectMonitor* val) NOT_JVMTI_RETURN JVMTI_ONLY({ _contended_entered_monitor = val; })
 760 
 761   // Support for object deoptimization and JFR suspension
 762   void handle_special_runtime_exit_condition();
 763   bool has_special_runtime_exit_condition() {
 764     return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
 765   }
 766 
 767   // Stack-locking support (not for LM_LIGHTWEIGHT)
 768   bool is_lock_owned(address adr) const;
 769 
 770   // Accessors for vframe array top
 771   // The linked list of vframe arrays are sorted on sp. This means when we
 772   // unpack the head must contain the vframe array to unpack.
 773   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
 774   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
 775 
 776   // Side structure for deferring update of java frame locals until deopt occurs
 777   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
 778   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
 779 
 780   // These only really exist to make debugging deopt problems simpler
 781 
 782   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
 783   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
 784 
 785   // The special resourceMark used during deoptimization
 786 
 787   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
 788   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
 789 
 790   void set_deopt_compiled_method(nmethod* nm)    { _deopt_nmethod = nm; }
 791   nmethod* deopt_compiled_method()               { return _deopt_nmethod; }
 792 
 793   Method*    callee_target() const               { return _callee_target; }
 794   void set_callee_target  (Method* x)            { _callee_target   = x; }
 795 
 796   // Oop results of vm runtime calls
 797   oop  vm_result() const                         { return _vm_result; }
 798   void set_vm_result  (oop x)                    { _vm_result   = x; }
 799 
 800   void set_vm_result_2  (Metadata* x)            { _vm_result_2   = x; }
 801 
 802   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
 803   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
 804 
 805   // Is thread in scope of an InternalOOMEMark?
 806   bool is_in_internal_oome_mark() const          { return _is_in_internal_oome_mark; }
 807   void set_is_in_internal_oome_mark(bool b)      { _is_in_internal_oome_mark = b;    }
 808 
 809 #if INCLUDE_JVMCI
 810   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
 811   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
 812   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
 813   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
 814   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
 815   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == nullptr, "must be"); _jvmci._alternate_call_target = a; }
 816   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == nullptr, "must be"); _jvmci._implicit_exception_pc = a; }
 817 
 818   JVMCIRuntime* libjvmci_runtime() const          { return _libjvmci_runtime; }
 819   void set_libjvmci_runtime(JVMCIRuntime* rt) {
 820     assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
 821     _libjvmci_runtime = rt;
 822   }
 823 #endif // INCLUDE_JVMCI
 824 
 825   // Exception handling for compiled methods
 826   oop      exception_oop() const;
 827   address  exception_pc() const                  { return _exception_pc; }
 828 
 829   void set_exception_oop(oop o);
 830   void set_exception_pc(address a)               { _exception_pc = a; }
 831   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
 832   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
 833 
 834   void clear_exception_oop_and_pc() {
 835     set_exception_oop(nullptr);
 836     set_exception_pc(nullptr);
 837   }
 838 
 839   // Check if address is in the usable part of the stack (excludes protected
 840   // guard pages). Can be applied to any thread and is an approximation for
 841   // using is_in_live_stack when the query has to happen from another thread.
 842   bool is_in_usable_stack(address adr) const {
 843     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
 844   }
 845 
 846   // Misc. accessors/mutators
 847   static ByteSize scopedValueCache_offset()       { return byte_offset_of(JavaThread, _scopedValueCache); }
 848 
 849   // For assembly stub generation
 850   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
 851   static ByteSize vthread_offset()               { return byte_offset_of(JavaThread, _vthread); }
 852   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
 853   static ByteSize pending_jni_exception_check_fn_offset() {
 854     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
 855   }
 856   static ByteSize last_Java_sp_offset() {
 857     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
 858   }
 859   static ByteSize last_Java_pc_offset() {
 860     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
 861   }
 862   static ByteSize frame_anchor_offset() {
 863     return byte_offset_of(JavaThread, _anchor);
 864   }
 865   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
 866   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
 867   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
 868   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
 869   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
 870   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
 871 #if INCLUDE_JVMCI
 872   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
 873   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
 874   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
 875   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
 876   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
 877 #endif // INCLUDE_JVMCI
 878   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
 879   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
 880   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
 881   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
 882 
 883   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
 884 
 885   // StackOverflow offsets
 886   static ByteSize stack_overflow_limit_offset()  {
 887     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
 888   }
 889   static ByteSize stack_guard_state_offset()     {
 890     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
 891   }
 892   static ByteSize reserved_stack_activation_offset() {
 893     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
 894   }
 895   static ByteSize shadow_zone_safe_limit()  {
 896     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
 897   }
 898   static ByteSize shadow_zone_growth_watermark()  {
 899     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
 900   }
 901 
 902   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
 903 
 904   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
 905   static ByteSize should_post_on_exceptions_flag_offset() {
 906     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
 907   }
 908   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
 909   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
 910 
 911   static ByteSize monitor_owner_id_offset()   { return byte_offset_of(JavaThread, _monitor_owner_id); }
 912 
 913   static ByteSize cont_entry_offset()         { return byte_offset_of(JavaThread, _cont_entry); }
 914   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
 915   static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
 916   static ByteSize jni_monitor_count_offset()  { return byte_offset_of(JavaThread, _jni_monitor_count); }
 917   static ByteSize preemption_cancelled_offset()  { return byte_offset_of(JavaThread, _preemption_cancelled); }
 918   static ByteSize preempt_alternate_return_offset() { return byte_offset_of(JavaThread, _preempt_alternate_return); }
 919   static ByteSize unlocked_inflated_monitor_offset() { return byte_offset_of(JavaThread, _unlocked_inflated_monitor); }
 920 
 921 #if INCLUDE_JVMTI
 922   static ByteSize is_in_VTMS_transition_offset()     { return byte_offset_of(JavaThread, _is_in_VTMS_transition); }
 923   static ByteSize is_disable_suspend_offset()        { return byte_offset_of(JavaThread, _is_disable_suspend); }
 924 #endif
 925 
 926   // Returns the jni environment for this thread
 927   JNIEnv* jni_environment()                      { return &_jni_environment; }
 928 
 929   // Returns the current thread as indicated by the given JNIEnv.
 930   // We don't assert it is Thread::current here as that is done at the
 931   // external JNI entry points where the JNIEnv is passed into the VM.
 932   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
 933     JavaThread* current = reinterpret_cast<JavaThread*>(((intptr_t)env - in_bytes(jni_environment_offset())));
 934     // We can't normally get here in a thread that has completed its
 935     // execution and so "is_terminated", except when the call is from
 936     // AsyncGetCallTrace, which can be triggered by a signal at any point in
 937     // a thread's lifecycle. A thread is also considered terminated if the VM
 938     // has exited, so we have to check this and block in case this is a daemon
 939     // thread returning to the VM (the JNI DirectBuffer entry points rely on
 940     // this).
 941     if (current->is_terminated()) {
 942       current->block_if_vm_exited();
 943     }
 944     return current;
 945   }
 946 
 947   // JNI critical regions. These can nest.
 948   bool in_critical()    { return _jni_active_critical > 0; }
 949   bool in_last_critical()  { return _jni_active_critical == 1; }
 950   inline void enter_critical();
 951   void exit_critical() {
 952     assert(Thread::current() == this, "this must be current thread");
 953     _jni_active_critical--;
 954     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
 955   }
 956 
 957   // Atomic version; invoked by a thread other than the owning thread.
 958   bool in_critical_atomic() { return Atomic::load(&_jni_active_critical) > 0; }
 959 
 960   // Checked JNI: is the programmer required to check for exceptions, if so specify
 961   // which function name. Returning to a Java frame should implicitly clear the
 962   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
 963   // VM->Java transitions are not cleared, it is expected that JNI code enclosed
 964   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
 965   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != nullptr; }
 966   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = nullptr; }
 967   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
 968   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
 969 
 970   // For deadlock detection
 971   int depth_first_number() { return _depth_first_number; }
 972   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
 973 
 974  public:
 975   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
 976   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
 977   void dec_in_deopt_handler() {
 978     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
 979     if (_in_deopt_handler > 0) { // robustness
 980       _in_deopt_handler--;
 981     }
 982   }
 983 
 984  private:
 985   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
 986 
 987   // factor out low-level mechanics for use in both normal and error cases
 988   const char* get_thread_name_string(char* buf = nullptr, int buflen = 0) const;
 989 
 990  public:
 991 
 992   // Frame iteration; calls the function f for all frames on the stack
 993   void frames_do(void f(frame*, const RegisterMap*));
 994 
 995   // Memory operations
 996   void oops_do_frames(OopClosure* f, NMethodClosure* cf);
 997   void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
 998 
 999   // GC operations
1000   virtual void nmethods_do(NMethodClosure* cf);
1001 
1002   // RedefineClasses Support
1003   void metadata_do(MetadataClosure* f);
1004 
1005   // Debug method asserting thread states are correct during a handshake operation.
1006   DEBUG_ONLY(void verify_states_for_handshake();)
1007 
1008   // Misc. operations
1009   const char* name() const;
1010   const char* name_raw() const;
1011   const char* type_name() const { return "JavaThread"; }
1012   static const char* name_for(oop thread_obj);
1013 
1014   void print_on(outputStream* st, bool print_extended_info) const;
1015   void print_on(outputStream* st) const { print_on(st, false); }
1016   void print() const;
1017   void print_thread_state_on(outputStream*) const;
1018   void print_on_error(outputStream* st, char* buf, int buflen) const;
1019   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1020   void verify();
1021 
1022   // Accessing frames
1023   frame last_frame() {
1024     _anchor.make_walkable();
1025     return pd_last_frame();
1026   }
1027   javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
1028 
1029   frame carrier_last_frame(RegisterMap* reg_map);
1030   javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
1031 
1032   frame vthread_last_frame();
1033   javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
1034 
1035   frame platform_thread_last_frame(RegisterMap* reg_map);
1036   javaVFrame*  platform_thread_last_java_vframe(RegisterMap* reg_map) {
1037     return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
1038   }
1039 
1040   javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
1041 
1042   // Returns method at 'depth' java or native frames down the stack
1043   // Used for security checks
1044   Klass* security_get_caller_class(int depth);
1045 
1046   // Print stack trace in external format
1047   // These variants print carrier/platform thread information only.
1048   void print_stack_on(outputStream* st);
1049   void print_stack() { print_stack_on(tty); }
1050   // This prints the currently mounted virtual thread.
1051   void print_vthread_stack_on(outputStream* st);
1052   // This prints the active stack: either carrier/platform or virtual.
1053   void print_active_stack_on(outputStream* st);
1054   // Print current stack trace for checked JNI warnings and JNI fatal errors.
1055   // This is the external format from above, but selecting the platform
1056   // or vthread as applicable.
1057   void print_jni_stack();
1058 
1059   // Print stack traces in various internal formats
1060   void trace_stack()                             PRODUCT_RETURN;
1061   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1062   void trace_frames()                            PRODUCT_RETURN;
1063 
1064   // Print an annotated view of the stack frames
1065   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1066   void validate_frame_layout() {
1067     print_frame_layout(0, true);
1068   }
1069 
1070   // Function for testing deoptimization
1071   void deoptimize();
1072   void make_zombies();
1073 
1074   void deoptimize_marked_methods();
1075 
1076  public:
1077   // Returns the running thread as a JavaThread
1078   static JavaThread* current() {
1079     return JavaThread::cast(Thread::current());
1080   }
1081 
1082   // Returns the current thread as a JavaThread, or nullptr if not attached
1083   static inline JavaThread* current_or_null();
1084 
1085   // Casts
1086   static JavaThread* cast(Thread* t) {
1087     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1088     return static_cast<JavaThread*>(t);
1089   }
1090 
1091   static const JavaThread* cast(const Thread* t) {
1092     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1093     return static_cast<const JavaThread*>(t);
1094   }
1095 
1096   // Returns the active Java thread.  Do not use this if you know you are calling
1097   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1098   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1099   // operation.  You may not want that either.
1100   static JavaThread* active();
1101 
1102  protected:
1103   virtual void pre_run();
1104   virtual void run();
1105   void thread_main_inner();
1106   virtual void post_run();
1107 
1108  public:
1109   // Thread local information maintained by JVMTI.
1110   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1111   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1112   // getter is used to get this JavaThread's JvmtiThreadState if it has
1113   // one which means null can be returned. JvmtiThreadState::state_for()
1114   // is used to get the specified JavaThread's JvmtiThreadState if it has
1115   // one or it allocates a new JvmtiThreadState for the JavaThread and
1116   // returns it. JvmtiThreadState::state_for() will return null only if
1117   // the specified JavaThread is exiting.
1118   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1119   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1120 
1121 #if INCLUDE_JVMTI
1122   // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1123   JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1124 #endif
1125 
1126   // JVMTI PopFrame support
1127   // Setting and clearing popframe_condition
1128   // All of these enumerated values are bits. popframe_pending
1129   // indicates that a PopFrame() has been requested and not yet been
1130   // completed. popframe_processing indicates that that PopFrame() is in
1131   // the process of being completed. popframe_force_deopt_reexecution_bit
1132   // indicates that special handling is required when returning to a
1133   // deoptimized caller.
1134   enum PopCondition {
1135     popframe_inactive                      = 0x00,
1136     popframe_pending_bit                   = 0x01,
1137     popframe_processing_bit                = 0x02,
1138     popframe_force_deopt_reexecution_bit   = 0x04
1139   };
1140   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1141   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1142   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1143   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1144   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1145   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1146   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1147 
1148   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1149   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1150   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1151 
1152   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1153   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1154   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1155 
1156  private:
1157   // Saved incoming arguments to popped frame.
1158   // Used only when popped interpreted frame returns to deoptimized frame.
1159   void*    _popframe_preserved_args;
1160   int      _popframe_preserved_args_size;
1161 
1162  public:
1163   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1164   void* popframe_preserved_args();
1165   ByteSize popframe_preserved_args_size();
1166   WordSize popframe_preserved_args_size_in_words();
1167   void  popframe_free_preserved_args();
1168 
1169 
1170  private:
1171   JvmtiThreadState *_jvmti_thread_state;
1172 
1173   // Used by the interpreter in fullspeed mode for frame pop, method
1174   // entry, method exit and single stepping support. This field is
1175   // only set to non-zero at a safepoint or using a direct handshake
1176   // (see EnterInterpOnlyModeClosure).
1177   // It can be set to zero asynchronously to this threads execution (i.e., without
1178   // safepoint/handshake or a lock) so we have to be very careful.
1179   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1180   int               _interp_only_mode;
1181 
1182  public:
1183   // used by the interpreter for fullspeed debugging support (see above)
1184   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1185   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1186   int get_interp_only_mode()                { return _interp_only_mode; }
1187   int set_interp_only_mode(int val)         { return _interp_only_mode = val; }
1188   void increment_interp_only_mode()         { ++_interp_only_mode; }
1189   void decrement_interp_only_mode()         { --_interp_only_mode; }
1190 
1191   // support for cached flag that indicates whether exceptions need to be posted for this thread
1192   // if this is false, we can avoid deoptimizing when events are thrown
1193   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1194  private:
1195   int    _should_post_on_exceptions_flag;
1196 
1197  public:
1198   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1199 
1200  private:
1201   ThreadStatistics *_thread_stat;
1202 
1203  public:
1204   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1205 
1206   // Return a blocker object for which this thread is blocked parking.
1207   oop current_park_blocker();
1208 
1209  private:
1210   static size_t _stack_size_at_create;
1211 
1212  public:
1213   static inline size_t stack_size_at_create(void) {
1214     return _stack_size_at_create;
1215   }
1216   static inline void set_stack_size_at_create(size_t value) {
1217     _stack_size_at_create = value;
1218   }
1219 
1220   // Machine dependent stuff
1221 #include OS_CPU_HEADER(javaThread)
1222 
1223   // JSR166 per-thread parker
1224  private:
1225   Parker _parker;
1226  public:
1227   Parker* parker() { return &_parker; }
1228 
1229  public:
1230   // clearing/querying jni attach status
1231   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1232   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1233   inline void set_done_attaching_via_jni();
1234 
1235   // Stack dump assistance:
1236   // Track the class we want to initialize but for which we have to wait
1237   // on its init_lock() because it is already being initialized.
1238   void set_class_to_be_initialized(InstanceKlass* k);
1239   InstanceKlass* class_to_be_initialized() const;
1240 
1241   // The most recent active <clinit> invocation is tracked by this variable.
1242   // The setter returns the previous value, so it can be restored later if needed.
1243   InstanceKlass* set_class_being_initialized(InstanceKlass* k);
1244   InstanceKlass* class_being_initialized() const;
1245 
1246 private:
1247   InstanceKlass* _class_to_be_initialized;
1248   InstanceKlass* _class_being_initialized;
1249 
1250   // java.lang.Thread.sleep support
1251   ParkEvent * _SleepEvent;
1252 
1253 #if INCLUDE_JFR
1254   // Support for jdk.VirtualThreadPinned event
1255   freeze_result _last_freeze_fail_result;
1256   Ticks _last_freeze_fail_time;
1257 #endif
1258 
1259 public:
1260   bool sleep(jlong millis);
1261   bool sleep_nanos(jlong nanos);
1262 
1263   // java.lang.Thread interruption support
1264   void interrupt();
1265   bool is_interrupted(bool clear_interrupted);
1266 
1267 #if INCLUDE_JFR
1268   // Support for jdk.VirtualThreadPinned event
1269   freeze_result last_freeze_fail_result() { return _last_freeze_fail_result; }
1270   Ticks& last_freeze_fail_time() { return _last_freeze_fail_time; }
1271   void set_last_freeze_fail_result(freeze_result result);
1272 #endif
1273   void post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) NOT_JFR_RETURN();
1274 
1275 
1276   // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
1277   // the Java code in Object::wait which are not present in RawMonitorWait.
1278   bool get_and_clear_interrupted();
1279 
1280 private:
1281   LockStack _lock_stack;
1282   OMCache _om_cache;
1283 
1284 public:
1285   LockStack& lock_stack() { return _lock_stack; }
1286 
1287   static ByteSize lock_stack_offset()      { return byte_offset_of(JavaThread, _lock_stack); }
1288   // Those offsets are used in code generators to access the LockStack that is embedded in this
1289   // JavaThread structure. Those accesses are relative to the current thread, which
1290   // is typically in a dedicated register.
1291   static ByteSize lock_stack_top_offset()  { return lock_stack_offset() + LockStack::top_offset(); }
1292   static ByteSize lock_stack_base_offset() { return lock_stack_offset() + LockStack::base_offset(); }
1293 
1294   static ByteSize om_cache_offset()        { return byte_offset_of(JavaThread, _om_cache); }
1295   static ByteSize om_cache_oops_offset()   { return om_cache_offset() + OMCache::entries_offset(); }
1296 
1297   void om_set_monitor_cache(ObjectMonitor* monitor);
1298   void om_clear_monitor_cache();
1299   ObjectMonitor* om_get_from_monitor_cache(oop obj);
1300 
1301   static OopStorage* thread_oop_storage();
1302 
1303   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1304 
1305   // Helper function to create the java.lang.Thread object for a
1306   // VM-internal thread. The thread will have the given name and be
1307   // part of the System ThreadGroup.
1308   static Handle create_system_thread_object(const char* name, TRAPS);
1309 
1310   // Helper function to start a VM-internal daemon thread.
1311   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1312   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1313                                     Handle thread_oop, ThreadPriority prio);
1314 
1315   // Helper function to do vm_exit_on_initialization for osthread
1316   // resource allocation failure.
1317   static void vm_exit_on_osthread_failure(JavaThread* thread);
1318 
1319   // Deferred OopHandle release support
1320  private:
1321   // List of OopHandles to be released - guarded by the Service_lock.
1322   static OopHandleList* _oop_handle_list;
1323   // Add our OopHandles to the list for the service thread to release.
1324   void add_oop_handles_for_release();
1325   // Called by the ServiceThread to release the OopHandles.
1326   static void release_oop_handles();
1327   // Called by the ServiceThread to poll if there are any OopHandles to release.
1328   // Called when holding the Service_lock.
1329   static bool has_oop_handles_to_release() {
1330     return _oop_handle_list != nullptr;
1331   }
1332 };
1333 
1334 inline JavaThread* JavaThread::current_or_null() {
1335   Thread* current = Thread::current_or_null();
1336   return current != nullptr ? JavaThread::cast(current) : nullptr;
1337 }
1338 
1339 class UnlockFlagSaver {
1340   private:
1341     JavaThread* _thread;
1342     bool _do_not_unlock;
1343   public:
1344     UnlockFlagSaver(JavaThread* t) {
1345       _thread = t;
1346       _do_not_unlock = t->do_not_unlock_if_synchronized();
1347       t->set_do_not_unlock_if_synchronized(false);
1348     }
1349     ~UnlockFlagSaver() {
1350       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1351     }
1352 };
1353 
1354 class JNIHandleMark : public StackObj {
1355   JavaThread* _thread;
1356  public:
1357   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1358     thread->push_jni_handle_block();
1359   }
1360   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1361 };
1362 
1363 class NoPreemptMark {
1364   ContinuationEntry* _ce;
1365   bool _unpin;
1366  public:
1367   NoPreemptMark(JavaThread* thread) : _ce(thread->last_continuation()), _unpin(false) {
1368     if (_ce != nullptr) _unpin = _ce->pin();
1369   }
1370   ~NoPreemptMark() { if (_unpin) _ce->unpin(); }
1371 };
1372 
1373 class ThreadOnMonitorWaitedEvent {
1374   JavaThread* _thread;
1375  public:
1376   ThreadOnMonitorWaitedEvent(JavaThread* thread) : _thread(thread) {
1377     JVMTI_ONLY(_thread->set_on_monitor_waited_event(true);)
1378   }
1379   ~ThreadOnMonitorWaitedEvent() { JVMTI_ONLY(_thread->set_on_monitor_waited_event(false);) }
1380 };
1381 
1382 class ThreadInClassInitializer : public StackObj {
1383   JavaThread* _thread;
1384   InstanceKlass* _previous;
1385  public:
1386   ThreadInClassInitializer(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1387     _previous = _thread->class_being_initialized();
1388     _thread->set_class_being_initialized(ik);
1389   }
1390   ~ThreadInClassInitializer() {
1391     _thread->set_class_being_initialized(_previous);
1392   }
1393 };
1394 
1395 #endif // SHARE_RUNTIME_JAVATHREAD_HPP