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