1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #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/park.hpp"
  38 #include "runtime/safepointMechanism.hpp"
  39 #include "runtime/stackWatermarkSet.hpp"
  40 #include "runtime/stackOverflow.hpp"
  41 #include "runtime/thread.hpp"
  42 #include "runtime/threadHeapSampler.hpp"
  43 #include "runtime/threadStatisticalInfo.hpp"
  44 #include "utilities/exceptions.hpp"
  45 #include "utilities/globalDefinitions.hpp"
  46 #include "utilities/macros.hpp"
  47 #if INCLUDE_JFR
  48 #include "jfr/support/jfrThreadExtension.hpp"
  49 #endif
  50 
  51 class AsyncExceptionHandshake;
  52 class ContinuationEntry;
  53 class DeoptResourceMark;
  54 class JNIHandleBlock;
  55 class JVMCIRuntime;
  56 
  57 class JvmtiDeferredUpdates;
  58 class JvmtiSampledObjectAllocEventCollector;
  59 class JvmtiThreadState;
  60 
  61 class Metadata;
  62 class OopStorage;
  63 class OSThread;
  64 
  65 class ThreadsList;
  66 class ThreadSafepointState;
  67 class ThreadStatistics;
  68 
  69 class vframeArray;
  70 class vframe;
  71 class javaVFrame;
  72 
  73 class JavaThread;
  74 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
  75 
  76 class JavaThread: public Thread {
  77   friend class VMStructs;
  78   friend class JVMCIVMStructs;
  79   friend class WhiteBox;
  80   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
  81   friend class HandshakeState;
  82   friend class Continuation;
  83   friend class Threads;
  84  private:
  85   bool           _in_asgct;                      // Is set when this JavaThread is handling ASGCT call
  86   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
  87   OopHandle      _threadObj;                     // The Java level thread object
  88   OopHandle      _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
  89   OopHandle      _jvmti_vthread;
  90   OopHandle      _extentLocalCache;
  91 
  92   static OopStorage* _thread_oop_storage;
  93 
  94 #ifdef ASSERT
  95  private:
  96   int _java_call_counter;
  97 
  98  public:
  99   int  java_call_counter()                       { return _java_call_counter; }
 100   void inc_java_call_counter()                   { _java_call_counter++; }
 101   void dec_java_call_counter() {
 102     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 103     _java_call_counter--;
 104   }
 105  private:  // restore original namespace restriction
 106 #endif  // ifdef ASSERT
 107 
 108   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 109 
 110   ThreadFunction _entry_point;
 111 
 112   JNIEnv        _jni_environment;
 113 
 114   // Deopt support
 115   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 116 
 117   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 118   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 119   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 120   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
 121   // will be carried out as soon as possible which, in most cases, is just before deoptimization of
 122   // the frame, when control returns to it.
 123   JvmtiDeferredUpdates* _jvmti_deferred_updates;
 124 
 125   // Handshake value for fixing 6243940. We need a place for the i2c
 126   // adapter to store the callee Method*. This value is NEVER live
 127   // across a gc point so it does NOT have to be gc'd
 128   // The handshake is open ended since we can't be certain that it will
 129   // be NULLed. This is because we rarely ever see the race and end up
 130   // in handle_wrong_method which is the backend of the handshake. See
 131   // code in i2c adapters and handle_wrong_method.
 132 
 133   Method*       _callee_target;
 134 
 135   // Used to pass back results to the interpreter or generated code running Java code.
 136   oop           _vm_result;    // oop result is GC-preserved
 137   Metadata*     _vm_result_2;  // non-oop result
 138 
 139   // See ReduceInitialCardMarks: this holds the precise space interval of
 140   // the most recent slow path allocation for which compiled code has
 141   // elided card-marks for performance along the fast-path.
 142   MemRegion     _deferred_card_mark;
 143 
 144   ObjectMonitor* volatile _current_pending_monitor;     // ObjectMonitor this thread is waiting to lock
 145   bool           _current_pending_monitor_is_from_java; // locking is from Java code
 146   ObjectMonitor* volatile _current_waiting_monitor;     // ObjectMonitor on which this thread called Object.wait()
 147 
 148   // Active_handles points to a block of handles
 149   JNIHandleBlock* _active_handles;
 150 
 151   // One-element thread local free list
 152   JNIHandleBlock* _free_handle_block;
 153 
 154  public:
 155   volatile intptr_t _Stalled;
 156 
 157   // For tracking the heavyweight monitor the thread is pending on.
 158   ObjectMonitor* current_pending_monitor() {
 159     // Use Atomic::load() to prevent data race between concurrent modification and
 160     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 161     // Especially, reloading pointer from thread after NULL check must be prevented.
 162     return Atomic::load(&_current_pending_monitor);
 163   }
 164   void set_current_pending_monitor(ObjectMonitor* monitor) {
 165     Atomic::store(&_current_pending_monitor, monitor);
 166   }
 167   void set_current_pending_monitor_is_from_java(bool from_java) {
 168     _current_pending_monitor_is_from_java = from_java;
 169   }
 170   bool current_pending_monitor_is_from_java() {
 171     return _current_pending_monitor_is_from_java;
 172   }
 173   ObjectMonitor* current_waiting_monitor() {
 174     // See the comment in current_pending_monitor() above.
 175     return Atomic::load(&_current_waiting_monitor);
 176   }
 177   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 178     Atomic::store(&_current_waiting_monitor, monitor);
 179   }
 180 
 181   // JNI handle support
 182   JNIHandleBlock* active_handles() const         { return _active_handles; }
 183   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 184   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 185   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 186 
 187   void push_jni_handle_block();
 188   void pop_jni_handle_block();
 189 
 190  private:
 191   MonitorChunk* _monitor_chunks;              // Contains the off stack monitors
 192                                               // allocated during deoptimization
 193                                               // and by JNI_MonitorEnter/Exit
 194 
 195   enum SuspendFlags {
 196     // NOTE: avoid using the sign-bit as cc generates different test code
 197     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 198     _trace_flag             = 0x00000004U, // call tracing backend
 199     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 200   };
 201 
 202   // various suspension related flags - atomically updated
 203   volatile uint32_t _suspend_flags;
 204 
 205   inline void set_suspend_flag(SuspendFlags f);
 206   inline void clear_suspend_flag(SuspendFlags f);
 207 
 208  public:
 209   inline void set_trace_flag();
 210   inline void clear_trace_flag();
 211   inline void set_obj_deopt_flag();
 212   inline void clear_obj_deopt_flag();
 213   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 214   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 215 
 216   // Asynchronous exception support
 217  private:
 218   friend class InstallAsyncExceptionHandshake;
 219   friend class AsyncExceptionHandshake;
 220   friend class HandshakeState;
 221 
 222   void install_async_exception(AsyncExceptionHandshake* aec = NULL);
 223   void handle_async_exception(oop java_throwable);
 224  public:
 225   bool has_async_exception_condition();
 226   inline void set_pending_unsafe_access_error();
 227   static void send_async_exception(JavaThread* jt, oop java_throwable);
 228 
 229   class NoAsyncExceptionDeliveryMark : public StackObj {
 230     friend JavaThread;
 231     JavaThread *_target;
 232     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 233     inline ~NoAsyncExceptionDeliveryMark();
 234   };
 235 
 236   // Safepoint support
 237  public:                                                        // Expose _thread_state for SafeFetchInt()
 238   volatile JavaThreadState _thread_state;
 239  private:
 240   SafepointMechanism::ThreadData _poll_data;
 241   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 242   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 243   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 244 #ifdef ASSERT
 245   // Debug support for checking if code allows safepoints or not.
 246   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 247   // mutex, or blocking on an object synchronizer (Java locking).
 248   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 249   // the above cases. The class NoSafepointVerifier is used to set this counter.
 250   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 251 
 252  public:
 253   void inc_no_safepoint_count() { _no_safepoint_count++; }
 254   void dec_no_safepoint_count() { _no_safepoint_count--; }
 255 #endif // ASSERT
 256  public:
 257   // These functions check conditions before possibly going to a safepoint.
 258   // including NoSafepointVerifier.
 259   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 260   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 261 
 262 #ifdef ASSERT
 263  private:
 264   volatile uint64_t _visited_for_critical_count;
 265 
 266  public:
 267   void set_visited_for_critical_count(uint64_t safepoint_id) {
 268     assert(_visited_for_critical_count == 0, "Must be reset before set");
 269     assert((safepoint_id & 0x1) == 1, "Must be odd");
 270     _visited_for_critical_count = safepoint_id;
 271   }
 272   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 273     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 274     _visited_for_critical_count = 0;
 275   }
 276   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 277     return _visited_for_critical_count == safepoint_id;
 278   }
 279 #endif // ASSERT
 280 
 281   // JavaThread termination support
 282  public:
 283   enum TerminatedTypes {
 284     _not_terminated = 0xDEAD - 3,
 285     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 286     _thread_gc_barrier_detached,                 // thread's GC barrier has been detached
 287     _thread_terminated,                          // JavaThread is removed from thread list
 288     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 289                                                  // only VM_Exit can set _vm_exited
 290   };
 291 
 292  private:
 293   // In general a JavaThread's _terminated field transitions as follows:
 294   //
 295   //   _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
 296   //
 297   // _vm_exited is a special value to cover the case of a JavaThread
 298   // executing native code after the VM itself is terminated.
 299   //
 300   // A JavaThread that fails to JNI attach has these _terminated field transitions:
 301   //   _not_terminated => _thread_terminated
 302   //
 303   volatile TerminatedTypes _terminated;
 304 
 305   jint                  _in_deopt_handler;       // count of deoptimization
 306                                                  // handlers thread is in
 307   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 308   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 309                                                          // never locked) when throwing an exception. Used by interpreter only.
 310 #if INCLUDE_JVMTI
 311   volatile bool         _carrier_thread_suspended;       // Carrier thread is externally suspended
 312   bool                  _is_in_VTMS_transition;          // thread is in virtual thread mount state transition
 313   bool                  _is_in_tmp_VTMS_transition;      // thread is in temporary virtual thread mount state transition
 314 #ifdef ASSERT
 315   bool                  _is_VTMS_transition_disabler;    // thread currently disabled VTMS transitions
 316 #endif
 317 #endif
 318 
 319   // JNI attach states:
 320   enum JNIAttachStates {
 321     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 322     _attaching_via_jni,          // thread is attaching via JNI
 323     _attached_via_jni            // thread has attached via JNI
 324   };
 325 
 326   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 327   // A native thread that is attaching via JNI starts with a value
 328   // of _attaching_via_jni and transitions to _attached_via_jni.
 329   volatile JNIAttachStates _jni_attach_state;
 330 
 331 
 332 #if INCLUDE_JVMCI
 333   // The _pending_* fields below are used to communicate extra information
 334   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 335 
 336   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 337   int       _pending_deoptimization;
 338 
 339   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 340   // before the monitor has been acquired.
 341   bool      _pending_monitorenter;
 342 
 343   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 344   bool      _pending_transfer_to_interpreter;
 345 
 346   // True if in a runtime call from compiled code that will deoptimize
 347   // and re-execute a failed heap allocation in the interpreter.
 348   bool      _in_retryable_allocation;
 349 
 350   // An id of a speculation that JVMCI compiled code can use to further describe and
 351   // uniquely identify the speculative optimization guarded by an uncommon trap.
 352   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 353   jlong     _pending_failed_speculation;
 354 
 355   // These fields are mutually exclusive in terms of live ranges.
 356   union {
 357     // Communicates the pc at which the most recent implicit exception occurred
 358     // from the signal handler to a deoptimization stub.
 359     address   _implicit_exception_pc;
 360 
 361     // Communicates an alternative call target to an i2c stub from a JavaCall .
 362     address   _alternate_call_target;
 363   } _jvmci;
 364 
 365   // The JVMCIRuntime in a JVMCI shared library
 366   JVMCIRuntime* _libjvmci_runtime;
 367 
 368   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 369   jlong*    _jvmci_counters;
 370 
 371   // Fast thread locals for use by JVMCI
 372   jlong      _jvmci_reserved0;
 373   jlong      _jvmci_reserved1;
 374   oop        _jvmci_reserved_oop0;
 375 
 376  public:
 377   static jlong* _jvmci_old_thread_counters;
 378   static void collect_counters(jlong* array, int length);
 379 
 380   bool resize_counters(int current_size, int new_size);
 381 
 382   static bool resize_all_jvmci_counters(int new_size);
 383 
 384   void set_jvmci_reserved_oop0(oop value) {
 385     _jvmci_reserved_oop0 = value;
 386   }
 387 
 388   oop get_jvmci_reserved_oop0() {
 389     return _jvmci_reserved_oop0;
 390   }
 391 
 392   void set_jvmci_reserved0(jlong value) {
 393     _jvmci_reserved0 = value;
 394   }
 395 
 396   jlong get_jvmci_reserved0() {
 397     return _jvmci_reserved0;
 398   }
 399 
 400   void set_jvmci_reserved1(jlong value) {
 401     _jvmci_reserved1 = value;
 402   }
 403 
 404   jlong get_jvmci_reserved1() {
 405     return _jvmci_reserved1;
 406   }
 407 
 408  private:
 409 #endif // INCLUDE_JVMCI
 410 
 411   StackOverflow    _stack_overflow_state;
 412 
 413   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 414   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 415   // code)
 416   volatile oop     _exception_oop;               // Exception thrown in compiled code
 417   volatile address _exception_pc;                // PC where exception happened
 418   volatile address _exception_handler_pc;        // PC for handler of exception
 419   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 420 
 421  private:
 422   // support for JNI critical regions
 423   jint    _jni_active_critical;                  // count of entries into JNI critical region
 424 
 425   // Checked JNI: function name requires exception check
 426   char* _pending_jni_exception_check_fn;
 427 
 428   // For deadlock detection.
 429   int _depth_first_number;
 430 
 431   // JVMTI PopFrame support
 432   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 433   int _popframe_condition;
 434 
 435   // If reallocation of scalar replaced objects fails, we throw OOM
 436   // and during exception propagation, pop the top
 437   // _frames_to_pop_failed_realloc frames, the ones that reference
 438   // failed reallocations.
 439   int _frames_to_pop_failed_realloc;
 440 
 441   ContinuationEntry* _cont_entry;
 442   intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub frame inside the
 443                             // continuation that we know about
 444   int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
 445   // It's signed for error detection.
 446 #ifdef _LP64
 447   int64_t _held_monitor_count;  // used by continuations for fast lock detection
 448   int64_t _jni_monitor_count;
 449 #else
 450   int32_t _held_monitor_count;  // used by continuations for fast lock detection
 451   int32_t _jni_monitor_count;
 452 #endif
 453 
 454 private:
 455 
 456   friend class VMThread;
 457   friend class ThreadWaitTransition;
 458   friend class VM_Exit;
 459 
 460   // Stack watermark barriers.
 461   StackWatermarks _stack_watermarks;
 462 
 463  public:
 464   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
 465 
 466  public:
 467   jlong _extentLocal_hash_table_shift;
 468 
 469   void allocate_extentLocal_hash_table(int count);
 470 
 471  public:
 472   // Constructor
 473   JavaThread();                            // delegating constructor
 474   JavaThread(bool is_attaching_via_jni);   // for main thread and JNI attached threads
 475   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 476   ~JavaThread();
 477 
 478 #ifdef ASSERT
 479   // verify this JavaThread hasn't be published in the Threads::list yet
 480   void verify_not_published();
 481 #endif // ASSERT
 482 
 483   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
 484 
 485   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 486   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 487     _jni_environment.functions = functionTable;
 488   }
 489   struct JNINativeInterface_* get_jni_functions() {
 490     return (struct JNINativeInterface_ *)_jni_environment.functions;
 491   }
 492 
 493   // This function is called at thread creation to allow
 494   // platform specific thread variables to be initialized.
 495   void cache_global_variables();
 496 
 497   // Executes Shutdown.shutdown()
 498   void invoke_shutdown_hooks();
 499 
 500   // Cleanup on thread exit
 501   enum ExitType {
 502     normal_exit,
 503     jni_detach
 504   };
 505   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 506 
 507   void cleanup_failed_attach_current_thread(bool is_daemon);
 508 
 509   // Testers
 510   virtual bool is_Java_thread() const            { return true;  }
 511   virtual bool can_call_java() const             { return true; }
 512 
 513   virtual bool is_active_Java_thread() const {
 514     return on_thread_list() && !is_terminated();
 515   }
 516 
 517   // Thread oop. threadObj() can be NULL for initial JavaThread
 518   // (or for threads attached via JNI)
 519   oop threadObj() const;
 520   void set_threadOopHandles(oop p);
 521   oop vthread() const;
 522   void set_vthread(oop p);
 523   oop extentLocalCache() const;
 524   void set_extentLocalCache(oop p);
 525   oop jvmti_vthread() const;
 526   void set_jvmti_vthread(oop p);
 527 
 528   // Prepare thread and add to priority queue.  If a priority is
 529   // not specified, use the priority of the thread object. Threads_lock
 530   // must be held while this function is called.
 531   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
 532 
 533   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
 534   address saved_exception_pc()                   { return _saved_exception_pc; }
 535 
 536   ThreadFunction entry_point() const             { return _entry_point; }
 537 
 538   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
 539   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
 540 
 541   // Last frame anchor routines
 542 
 543   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
 544 
 545   // last_Java_sp
 546   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
 547   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
 548 
 549   // last_Java_pc
 550 
 551   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
 552 
 553   // Safepoint support
 554   inline JavaThreadState thread_state() const;
 555   inline void set_thread_state(JavaThreadState s);
 556   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
 557   inline ThreadSafepointState* safepoint_state() const;
 558   inline void set_safepoint_state(ThreadSafepointState* state);
 559   inline bool is_at_poll_safepoint();
 560 
 561   // JavaThread termination and lifecycle support:
 562   void smr_delete();
 563   bool on_thread_list() const { return _on_thread_list; }
 564   void set_on_thread_list() { _on_thread_list = true; }
 565 
 566   // thread has called JavaThread::exit(), thread's GC barrier is detached
 567   // or thread is terminated
 568   bool is_exiting() const;
 569   // thread's GC barrier is NOT detached and thread is NOT terminated
 570   bool is_oop_safe() const;
 571   // thread is terminated (no longer on the threads list); the thread must
 572   // be protected by a ThreadsListHandle to avoid potential crashes.
 573   bool check_is_terminated(TerminatedTypes l_terminated) const {
 574     return l_terminated == _thread_terminated || l_terminated == _vm_exited;
 575   }
 576   bool is_terminated() const;
 577   void set_terminated(TerminatedTypes t);
 578 
 579   void block_if_vm_exited();
 580 
 581   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
 582   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
 583 
 584   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
 585   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
 586 
 587   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
 588 
 589   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
 590 
 591   // Continuation support
 592   oop get_continuation() const;
 593   ContinuationEntry* last_continuation() const { return _cont_entry; }
 594   void set_cont_fastpath(intptr_t* x)          { _cont_fastpath = x; }
 595   void push_cont_fastpath(intptr_t* sp)        { if (sp > _cont_fastpath) _cont_fastpath = sp; }
 596   void set_cont_fastpath_thread_state(bool x)  { _cont_fastpath_thread_state = (int)x; }
 597   intptr_t* raw_cont_fastpath() const          { return _cont_fastpath; }
 598   bool cont_fastpath() const                   { return _cont_fastpath == NULL && _cont_fastpath_thread_state != 0; }
 599   bool cont_fastpath_thread_state() const      { return _cont_fastpath_thread_state != 0; }
 600 
 601   void inc_held_monitor_count(int i = 1, bool jni = false);
 602   void dec_held_monitor_count(int i = 1, bool jni = false);
 603 
 604   int64_t held_monitor_count() { return (int64_t)_held_monitor_count; }
 605   int64_t jni_monitor_count()  { return (int64_t)_jni_monitor_count;  }
 606   void clear_jni_monitor_count() { _jni_monitor_count = 0;   }
 607 
 608   inline bool is_vthread_mounted() const;
 609   inline const ContinuationEntry* vthread_continuation() const;
 610 
 611  private:
 612   DEBUG_ONLY(void verify_frame_info();)
 613 
 614   // Support for thread handshake operations
 615   HandshakeState _handshake;
 616  public:
 617   HandshakeState* handshake_state() { return &_handshake; }
 618 
 619   // A JavaThread can always safely operate on it self and other threads
 620   // can do it safely if they are the active handshaker.
 621   bool is_handshake_safe_for(Thread* th) const {
 622     return _handshake.active_handshaker() == th || this == th;
 623   }
 624 
 625   // Suspend/resume support for JavaThread
 626   // higher-level suspension/resume logic called by the public APIs
 627   bool java_suspend();
 628   bool java_resume();
 629   bool is_suspended()     { return _handshake.is_suspended(); }
 630 
 631   // Check for async exception in addition to safepoint.
 632   static void check_special_condition_for_native_trans(JavaThread *thread);
 633 
 634   // Synchronize with another thread that is deoptimizing objects of the
 635   // current thread, i.e. reverts optimizations based on escape analysis.
 636   void wait_for_object_deoptimization();
 637 
 638 #if INCLUDE_JVMTI
 639   inline void set_carrier_thread_suspended();
 640   inline void clear_carrier_thread_suspended();
 641 
 642   bool is_carrier_thread_suspended() const {
 643     return _carrier_thread_suspended;
 644   }
 645 
 646   bool is_in_VTMS_transition() const             { return _is_in_VTMS_transition; }
 647   bool is_in_tmp_VTMS_transition() const         { return _is_in_tmp_VTMS_transition; }
 648   bool is_in_any_VTMS_transition() const         { return _is_in_VTMS_transition || _is_in_tmp_VTMS_transition; }
 649 
 650   void set_is_in_VTMS_transition(bool val);
 651   void toggle_is_in_tmp_VTMS_transition()        { _is_in_tmp_VTMS_transition = !_is_in_tmp_VTMS_transition; };
 652 
 653 #ifdef ASSERT
 654   bool is_VTMS_transition_disabler() const       { return _is_VTMS_transition_disabler; }
 655   void set_is_VTMS_transition_disabler(bool val);
 656 #endif
 657 #endif
 658 
 659   // Support for object deoptimization and JFR suspension
 660   void handle_special_runtime_exit_condition();
 661   bool has_special_runtime_exit_condition() {
 662     return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
 663   }
 664 
 665   // Fast-locking support
 666   bool is_lock_owned(address adr) const;
 667   bool is_lock_owned_current(address adr) const; // virtual if mounted, otherwise whole thread
 668   bool is_lock_owned_carrier(address adr) const;
 669 
 670   // Accessors for vframe array top
 671   // The linked list of vframe arrays are sorted on sp. This means when we
 672   // unpack the head must contain the vframe array to unpack.
 673   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
 674   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
 675 
 676   // Side structure for deferring update of java frame locals until deopt occurs
 677   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
 678   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
 679 
 680   // These only really exist to make debugging deopt problems simpler
 681 
 682   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
 683   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
 684 
 685   // The special resourceMark used during deoptimization
 686 
 687   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
 688   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
 689 
 690   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
 691   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
 692 
 693   Method*    callee_target() const               { return _callee_target; }
 694   void set_callee_target  (Method* x)          { _callee_target   = x; }
 695 
 696   // Oop results of vm runtime calls
 697   oop  vm_result() const                         { return _vm_result; }
 698   void set_vm_result  (oop x)                    { _vm_result   = x; }
 699 
 700   Metadata*    vm_result_2() const               { return _vm_result_2; }
 701   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
 702 
 703   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
 704   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
 705 
 706 #if INCLUDE_JVMCI
 707   int  pending_deoptimization() const             { return _pending_deoptimization; }
 708   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
 709   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
 710   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
 711   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
 712   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
 713   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
 714   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
 715   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
 716 
 717   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
 718   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
 719 
 720   JVMCIRuntime* libjvmci_runtime() const          { return _libjvmci_runtime; }
 721   void set_libjvmci_runtime(JVMCIRuntime* rt) {
 722     assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
 723     _libjvmci_runtime = rt;
 724   }
 725 #endif // INCLUDE_JVMCI
 726 
 727   // Exception handling for compiled methods
 728   oop      exception_oop() const;
 729   address  exception_pc() const                  { return _exception_pc; }
 730   address  exception_handler_pc() const          { return _exception_handler_pc; }
 731   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
 732 
 733   void set_exception_oop(oop o);
 734   void set_exception_pc(address a)               { _exception_pc = a; }
 735   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
 736   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
 737 
 738   void clear_exception_oop_and_pc() {
 739     set_exception_oop(NULL);
 740     set_exception_pc(NULL);
 741   }
 742 
 743   // Check if address is in the usable part of the stack (excludes protected
 744   // guard pages). Can be applied to any thread and is an approximation for
 745   // using is_in_live_stack when the query has to happen from another thread.
 746   bool is_in_usable_stack(address adr) const {
 747     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
 748   }
 749 
 750   // Misc. accessors/mutators
 751   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
 752   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
 753   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
 754 
 755   static ByteSize extentLocalCache_offset()       { return byte_offset_of(JavaThread, _extentLocalCache); }
 756 
 757   // For assembly stub generation
 758   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
 759   static ByteSize vthread_offset()               { return byte_offset_of(JavaThread, _vthread); }
 760   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
 761   static ByteSize pending_jni_exception_check_fn_offset() {
 762     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
 763   }
 764   static ByteSize last_Java_sp_offset() {
 765     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
 766   }
 767   static ByteSize last_Java_pc_offset() {
 768     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
 769   }
 770   static ByteSize frame_anchor_offset() {
 771     return byte_offset_of(JavaThread, _anchor);
 772   }
 773   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
 774   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
 775   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
 776   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
 777   static ByteSize polling_word_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_word);}
 778   static ByteSize polling_page_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_page);}
 779   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
 780   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
 781 #if INCLUDE_JVMCI
 782   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
 783   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
 784   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
 785   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
 786   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
 787   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
 788 #endif // INCLUDE_JVMCI
 789   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
 790   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
 791   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
 792   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
 793 
 794   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
 795 
 796   // StackOverflow offsets
 797   static ByteSize stack_overflow_limit_offset()  {
 798     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
 799   }
 800   static ByteSize stack_guard_state_offset()     {
 801     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
 802   }
 803   static ByteSize reserved_stack_activation_offset() {
 804     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
 805   }
 806   static ByteSize shadow_zone_safe_limit()  {
 807     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
 808   }
 809   static ByteSize shadow_zone_growth_watermark()  {
 810     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
 811   }
 812 
 813   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
 814 
 815   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
 816   static ByteSize should_post_on_exceptions_flag_offset() {
 817     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
 818   }
 819   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
 820   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
 821 
 822   static ByteSize cont_entry_offset()         { return byte_offset_of(JavaThread, _cont_entry); }
 823   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
 824   static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
 825 
 826   // Returns the jni environment for this thread
 827   JNIEnv* jni_environment()                      { return &_jni_environment; }
 828 
 829   // Returns the current thread as indicated by the given JNIEnv.
 830   // We don't assert it is Thread::current here as that is done at the
 831   // external JNI entry points where the JNIEnv is passed into the VM.
 832   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
 833     JavaThread* current = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
 834     // We can't normally get here in a thread that has completed its
 835     // execution and so "is_terminated", except when the call is from
 836     // AsyncGetCallTrace, which can be triggered by a signal at any point in
 837     // a thread's lifecycle. A thread is also considered terminated if the VM
 838     // has exited, so we have to check this and block in case this is a daemon
 839     // thread returning to the VM (the JNI DirectBuffer entry points rely on
 840     // this).
 841     if (current->is_terminated()) {
 842       current->block_if_vm_exited();
 843     }
 844     return current;
 845   }
 846 
 847   // JNI critical regions. These can nest.
 848   bool in_critical()    { return _jni_active_critical > 0; }
 849   bool in_last_critical()  { return _jni_active_critical == 1; }
 850   inline void enter_critical();
 851   void exit_critical() {
 852     assert(Thread::current() == this, "this must be current thread");
 853     _jni_active_critical--;
 854     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
 855   }
 856 
 857   // Checked JNI: is the programmer required to check for exceptions, if so specify
 858   // which function name. Returning to a Java frame should implicitly clear the
 859   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
 860   // VM->Java transitions are not cleared, it is expected that JNI code enclosed
 861   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
 862   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
 863   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
 864   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
 865   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
 866 
 867   // For deadlock detection
 868   int depth_first_number() { return _depth_first_number; }
 869   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
 870 
 871  private:
 872   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
 873 
 874  public:
 875   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
 876   void add_monitor_chunk(MonitorChunk* chunk);
 877   void remove_monitor_chunk(MonitorChunk* chunk);
 878   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
 879   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
 880   void dec_in_deopt_handler() {
 881     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
 882     if (_in_deopt_handler > 0) { // robustness
 883       _in_deopt_handler--;
 884     }
 885   }
 886 
 887  private:
 888   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
 889 
 890   // factor out low-level mechanics for use in both normal and error cases
 891   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
 892 
 893  public:
 894 
 895   // Frame iteration; calls the function f for all frames on the stack
 896   void frames_do(void f(frame*, const RegisterMap*));
 897 
 898   // Memory operations
 899   void oops_do_frames(OopClosure* f, CodeBlobClosure* cf);
 900   void oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf);
 901 
 902   // GC operations
 903   virtual void nmethods_do(CodeBlobClosure* cf);
 904 
 905   // RedefineClasses Support
 906   void metadata_do(MetadataClosure* f);
 907 
 908   // Debug method asserting thread states are correct during a handshake operation.
 909   DEBUG_ONLY(void verify_states_for_handshake();)
 910 
 911   // Misc. operations
 912   const char* name() const;
 913   const char* type_name() const { return "JavaThread"; }
 914   static const char* name_for(oop thread_obj);
 915 
 916   void print_on(outputStream* st, bool print_extended_info) const;
 917   void print_on(outputStream* st) const { print_on(st, false); }
 918   void print() const;
 919   void print_thread_state_on(outputStream*) const;
 920   const char* thread_state_name() const;
 921   void print_on_error(outputStream* st, char* buf, int buflen) const;
 922   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
 923   void verify();
 924 
 925   // Accessing frames
 926   frame last_frame() {
 927     _anchor.make_walkable();
 928     return pd_last_frame();
 929   }
 930   javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
 931 
 932   frame carrier_last_frame(RegisterMap* reg_map);
 933   javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
 934 
 935   frame vthread_last_frame();
 936   javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
 937 
 938   frame platform_thread_last_frame(RegisterMap* reg_map);
 939   javaVFrame*  platform_thread_last_java_vframe(RegisterMap* reg_map) {
 940     return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
 941   }
 942 
 943   javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
 944 
 945   // Returns method at 'depth' java or native frames down the stack
 946   // Used for security checks
 947   Klass* security_get_caller_class(int depth);
 948 
 949   // Print stack trace in external format
 950   void print_stack_on(outputStream* st);
 951   void print_stack() { print_stack_on(tty); }
 952 
 953   // Print stack traces in various internal formats
 954   void trace_stack()                             PRODUCT_RETURN;
 955   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
 956   void trace_frames()                            PRODUCT_RETURN;
 957 
 958   // Print an annotated view of the stack frames
 959   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
 960   void validate_frame_layout() {
 961     print_frame_layout(0, true);
 962   }
 963 
 964   // Function for testing deoptimization
 965   void deoptimize();
 966   void make_zombies();
 967 
 968   void deoptimize_marked_methods();
 969 
 970  public:
 971   // Returns the running thread as a JavaThread
 972   static JavaThread* current() {
 973     return JavaThread::cast(Thread::current());
 974   }
 975 
 976   // Returns the current thread as a JavaThread, or NULL if not attached
 977   static inline JavaThread* current_or_null();
 978 
 979   // Casts
 980   static JavaThread* cast(Thread* t) {
 981     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
 982     return static_cast<JavaThread*>(t);
 983   }
 984 
 985   static const JavaThread* cast(const Thread* t) {
 986     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
 987     return static_cast<const JavaThread*>(t);
 988   }
 989 
 990   // Returns the active Java thread.  Do not use this if you know you are calling
 991   // from a JavaThread, as it's slower than JavaThread::current.  If called from
 992   // the VMThread, it also returns the JavaThread that instigated the VMThread's
 993   // operation.  You may not want that either.
 994   static JavaThread* active();
 995 
 996  protected:
 997   virtual void pre_run();
 998   virtual void run();
 999   void thread_main_inner();
1000   virtual void post_run();
1001 
1002  public:
1003   // Thread local information maintained by JVMTI.
1004   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1005   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1006   // getter is used to get this JavaThread's JvmtiThreadState if it has
1007   // one which means NULL can be returned. JvmtiThreadState::state_for()
1008   // is used to get the specified JavaThread's JvmtiThreadState if it has
1009   // one or it allocates a new JvmtiThreadState for the JavaThread and
1010   // returns it. JvmtiThreadState::state_for() will return NULL only if
1011   // the specified JavaThread is exiting.
1012   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1013   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1014 
1015 #if INCLUDE_JVMTI
1016   // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1017   JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1018 #endif
1019 
1020   // JVMTI PopFrame support
1021   // Setting and clearing popframe_condition
1022   // All of these enumerated values are bits. popframe_pending
1023   // indicates that a PopFrame() has been requested and not yet been
1024   // completed. popframe_processing indicates that that PopFrame() is in
1025   // the process of being completed. popframe_force_deopt_reexecution_bit
1026   // indicates that special handling is required when returning to a
1027   // deoptimized caller.
1028   enum PopCondition {
1029     popframe_inactive                      = 0x00,
1030     popframe_pending_bit                   = 0x01,
1031     popframe_processing_bit                = 0x02,
1032     popframe_force_deopt_reexecution_bit   = 0x04
1033   };
1034   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1035   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1036   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1037   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1038   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1039   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1040   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1041   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1042 
1043   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1044   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1045   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1046 
1047   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1048   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1049   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1050 
1051  private:
1052   // Saved incoming arguments to popped frame.
1053   // Used only when popped interpreted frame returns to deoptimized frame.
1054   void*    _popframe_preserved_args;
1055   int      _popframe_preserved_args_size;
1056 
1057  public:
1058   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1059   void* popframe_preserved_args();
1060   ByteSize popframe_preserved_args_size();
1061   WordSize popframe_preserved_args_size_in_words();
1062   void  popframe_free_preserved_args();
1063 
1064 
1065  private:
1066   JvmtiThreadState *_jvmti_thread_state;
1067 
1068   // Used by the interpreter in fullspeed mode for frame pop, method
1069   // entry, method exit and single stepping support. This field is
1070   // only set to non-zero at a safepoint or using a direct handshake
1071   // (see EnterInterpOnlyModeClosure).
1072   // It can be set to zero asynchronously to this threads execution (i.e., without
1073   // safepoint/handshake or a lock) so we have to be very careful.
1074   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1075   int               _interp_only_mode;
1076 
1077  public:
1078   // used by the interpreter for fullspeed debugging support (see above)
1079   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1080   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1081   int get_interp_only_mode()                { return _interp_only_mode; }
1082   int set_interp_only_mode(int val)         { return _interp_only_mode = val; }
1083   void increment_interp_only_mode()         { ++_interp_only_mode; }
1084   void decrement_interp_only_mode()         { --_interp_only_mode; }
1085 
1086   // support for cached flag that indicates whether exceptions need to be posted for this thread
1087   // if this is false, we can avoid deoptimizing when events are thrown
1088   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1089  private:
1090   int    _should_post_on_exceptions_flag;
1091 
1092  public:
1093   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1094   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1095 
1096  private:
1097   ThreadStatistics *_thread_stat;
1098 
1099  public:
1100   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1101 
1102   // Return a blocker object for which this thread is blocked parking.
1103   oop current_park_blocker();
1104 
1105  private:
1106   static size_t _stack_size_at_create;
1107 
1108  public:
1109   static inline size_t stack_size_at_create(void) {
1110     return _stack_size_at_create;
1111   }
1112   static inline void set_stack_size_at_create(size_t value) {
1113     _stack_size_at_create = value;
1114   }
1115 
1116   // Machine dependent stuff
1117 #include OS_CPU_HEADER(javaThread)
1118 
1119   // JSR166 per-thread parker
1120  private:
1121   Parker _parker;
1122  public:
1123   Parker* parker() { return &_parker; }
1124 
1125  public:
1126   // clearing/querying jni attach status
1127   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1128   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1129   inline void set_done_attaching_via_jni();
1130 
1131   // Stack dump assistance:
1132   // Track the class we want to initialize but for which we have to wait
1133   // on its init_lock() because it is already being initialized.
1134   void set_class_to_be_initialized(InstanceKlass* k);
1135   InstanceKlass* class_to_be_initialized() const;
1136 
1137 private:
1138   InstanceKlass* _class_to_be_initialized;
1139 
1140   // java.lang.Thread.sleep support
1141   ParkEvent * _SleepEvent;
1142 public:
1143   bool sleep(jlong millis);
1144 
1145   // java.lang.Thread interruption support
1146   void interrupt();
1147   bool is_interrupted(bool clear_interrupted);
1148 
1149   static OopStorage* thread_oop_storage();
1150 
1151   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1152 
1153   // Helper function to create the java.lang.Thread object for a
1154   // VM-internal thread. The thread will have the given name, be
1155   // part of the System ThreadGroup and if is_visible is true will be
1156   // discoverable via the system ThreadGroup.
1157   static Handle create_system_thread_object(const char* name, bool is_visible, TRAPS);
1158 
1159   // Helper function to start a VM-internal daemon thread.
1160   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1161   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1162                                     Handle thread_oop, ThreadPriority prio);
1163 
1164   // Helper function to do vm_exit_on_initialization for osthread
1165   // resource allocation failure.
1166   static void vm_exit_on_osthread_failure(JavaThread* thread);
1167 
1168   // AsyncGetCallTrace support
1169   inline bool in_asgct(void) {return _in_asgct;}
1170   inline void set_in_asgct(bool value) {_in_asgct = value;}
1171 };
1172 
1173 inline JavaThread* JavaThread::current_or_null() {
1174   Thread* current = Thread::current_or_null();
1175   return current != nullptr ? JavaThread::cast(current) : nullptr;
1176 }
1177 
1178 class UnlockFlagSaver {
1179   private:
1180     JavaThread* _thread;
1181     bool _do_not_unlock;
1182   public:
1183     UnlockFlagSaver(JavaThread* t) {
1184       _thread = t;
1185       _do_not_unlock = t->do_not_unlock_if_synchronized();
1186       t->set_do_not_unlock_if_synchronized(false);
1187     }
1188     ~UnlockFlagSaver() {
1189       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1190     }
1191 };
1192 
1193 class JNIHandleMark : public StackObj {
1194   JavaThread* _thread;
1195  public:
1196   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1197     thread->push_jni_handle_block();
1198   }
1199   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1200 };
1201 
1202 #endif // SHARE_RUNTIME_JAVATHREAD_HPP