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