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 OopHandleList;
  63 class OopStorage;
  64 class OSThread;
  65 
  66 class ThreadsList;
  67 class ThreadSafepointState;
  68 class ThreadStatistics;
  69 
  70 class vframeArray;
  71 class vframe;
  72 class javaVFrame;
  73 
  74 class JavaThread;
  75 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
  76 
  77 class JavaThread: public Thread {
  78   friend class VMStructs;
  79   friend class JVMCIVMStructs;
  80   friend class WhiteBox;
  81   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
  82   friend class HandshakeState;
  83   friend class Continuation;
  84   friend class Threads;
  85   friend class ServiceThread; // for deferred OopHandle release access
  86  private:
  87   bool           _in_asgct;                      // Is set when this JavaThread is handling ASGCT call
  88   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
  89 
  90   // All references to Java objects managed via OopHandles. These
  91   // have to be released by the ServiceThread after the JavaThread has
  92   // terminated - see add_oop_handles_for_release().
  93   OopHandle      _threadObj;                     // The Java level thread object
  94   OopHandle      _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
  95   OopHandle      _jvmti_vthread;
  96   OopHandle      _scopedValueCache;
  97 
  98   static OopStorage* _thread_oop_storage;
  99 
 100 #ifdef ASSERT
 101  private:
 102   int _java_call_counter;
 103 
 104  public:
 105   int  java_call_counter()                       { return _java_call_counter; }
 106   void inc_java_call_counter()                   { _java_call_counter++; }
 107   void dec_java_call_counter() {
 108     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 109     _java_call_counter--;
 110   }
 111  private:  // restore original namespace restriction
 112 #endif  // ifdef ASSERT
 113 
 114   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 115 
 116   ThreadFunction _entry_point;
 117 
 118   JNIEnv        _jni_environment;
 119 
 120   // Deopt support
 121   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 122 
 123   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 124   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 125   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 126   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
 127   // will be carried out as soon as possible which, in most cases, is just before deoptimization of
 128   // the frame, when control returns to it.
 129   JvmtiDeferredUpdates* _jvmti_deferred_updates;
 130 
 131   // Handshake value for fixing 6243940. We need a place for the i2c
 132   // adapter to store the callee Method*. This value is NEVER live
 133   // across a gc point so it does NOT have to be gc'd
 134   // The handshake is open ended since we can't be certain that it will
 135   // be NULLed. This is because we rarely ever see the race and end up
 136   // in handle_wrong_method which is the backend of the handshake. See
 137   // code in i2c adapters and handle_wrong_method.
 138 
 139   Method*       _callee_target;
 140 
 141   // Used to pass back results to the interpreter or generated code running Java code.
 142   oop           _vm_result;    // oop result is GC-preserved
 143   Metadata*     _vm_result_2;  // non-oop result
 144 
 145   // See ReduceInitialCardMarks: this holds the precise space interval of
 146   // the most recent slow path allocation for which compiled code has
 147   // elided card-marks for performance along the fast-path.
 148   MemRegion     _deferred_card_mark;
 149 
 150   ObjectMonitor* volatile _current_pending_monitor;     // ObjectMonitor this thread is waiting to lock
 151   bool           _current_pending_monitor_is_from_java; // locking is from Java code
 152   ObjectMonitor* volatile _current_waiting_monitor;     // ObjectMonitor on which this thread called Object.wait()
 153 
 154   // Active_handles points to a block of handles
 155   JNIHandleBlock* _active_handles;
 156 
 157   // One-element thread local free list
 158   JNIHandleBlock* _free_handle_block;
 159 
 160  public:
 161   volatile intptr_t _Stalled;
 162 
 163   // For tracking the heavyweight monitor the thread is pending on.
 164   ObjectMonitor* current_pending_monitor() {
 165     // Use Atomic::load() to prevent data race between concurrent modification and
 166     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 167     // Especially, reloading pointer from thread after NULL check must be prevented.
 168     return Atomic::load(&_current_pending_monitor);
 169   }
 170   void set_current_pending_monitor(ObjectMonitor* monitor) {
 171     Atomic::store(&_current_pending_monitor, monitor);
 172   }
 173   void set_current_pending_monitor_is_from_java(bool from_java) {
 174     _current_pending_monitor_is_from_java = from_java;
 175   }
 176   bool current_pending_monitor_is_from_java() {
 177     return _current_pending_monitor_is_from_java;
 178   }
 179   ObjectMonitor* current_waiting_monitor() {
 180     // See the comment in current_pending_monitor() above.
 181     return Atomic::load(&_current_waiting_monitor);
 182   }
 183   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 184     Atomic::store(&_current_waiting_monitor, monitor);
 185   }
 186 
 187   // JNI handle support
 188   JNIHandleBlock* active_handles() const         { return _active_handles; }
 189   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 190   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 191   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 192 
 193   void push_jni_handle_block();
 194   void pop_jni_handle_block();
 195 
 196  private:
 197   MonitorChunk* _monitor_chunks;              // Contains the off stack monitors
 198                                               // allocated during deoptimization
 199                                               // and by JNI_MonitorEnter/Exit
 200 
 201   enum SuspendFlags {
 202     // NOTE: avoid using the sign-bit as cc generates different test code
 203     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 204     _trace_flag             = 0x00000004U, // call tracing backend
 205     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 206   };
 207 
 208   // various suspension related flags - atomically updated
 209   volatile uint32_t _suspend_flags;
 210 
 211   inline void set_suspend_flag(SuspendFlags f);
 212   inline void clear_suspend_flag(SuspendFlags f);
 213 
 214  public:
 215   inline void set_trace_flag();
 216   inline void clear_trace_flag();
 217   inline void set_obj_deopt_flag();
 218   inline void clear_obj_deopt_flag();
 219   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 220   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 221 
 222   // Asynchronous exception support
 223  private:
 224   friend class InstallAsyncExceptionHandshake;
 225   friend class AsyncExceptionHandshake;
 226   friend class HandshakeState;
 227 
 228   void install_async_exception(AsyncExceptionHandshake* aec = NULL);
 229   void handle_async_exception(oop java_throwable);
 230  public:
 231   bool has_async_exception_condition();
 232   inline void set_pending_unsafe_access_error();
 233   static void send_async_exception(JavaThread* jt, oop java_throwable);
 234 
 235   class NoAsyncExceptionDeliveryMark : public StackObj {
 236     friend JavaThread;
 237     JavaThread *_target;
 238     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 239     inline ~NoAsyncExceptionDeliveryMark();
 240   };
 241 
 242   // Safepoint support
 243  public:                                                        // Expose _thread_state for SafeFetchInt()
 244   volatile JavaThreadState _thread_state;
 245  private:
 246   SafepointMechanism::ThreadData _poll_data;
 247   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 248   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 249   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 250 #ifdef ASSERT
 251   // Debug support for checking if code allows safepoints or not.
 252   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 253   // mutex, or blocking on an object synchronizer (Java locking).
 254   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 255   // the above cases. The class NoSafepointVerifier is used to set this counter.
 256   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 257 
 258  public:
 259   void inc_no_safepoint_count() { _no_safepoint_count++; }
 260   void dec_no_safepoint_count() { _no_safepoint_count--; }
 261 #endif // ASSERT
 262  public:
 263   // These functions check conditions before possibly going to a safepoint.
 264   // including NoSafepointVerifier.
 265   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 266   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 267 
 268 #ifdef ASSERT
 269  private:
 270   volatile uint64_t _visited_for_critical_count;
 271 
 272  public:
 273   void set_visited_for_critical_count(uint64_t safepoint_id) {
 274     assert(_visited_for_critical_count == 0, "Must be reset before set");
 275     assert((safepoint_id & 0x1) == 1, "Must be odd");
 276     _visited_for_critical_count = safepoint_id;
 277   }
 278   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 279     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 280     _visited_for_critical_count = 0;
 281   }
 282   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 283     return _visited_for_critical_count == safepoint_id;
 284   }
 285 #endif // ASSERT
 286 
 287   // JavaThread termination support
 288  public:
 289   enum TerminatedTypes {
 290     _not_terminated = 0xDEAD - 3,
 291     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 292     _thread_gc_barrier_detached,                 // thread's GC barrier has been detached
 293     _thread_terminated,                          // JavaThread is removed from thread list
 294     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 295                                                  // only VM_Exit can set _vm_exited
 296   };
 297 
 298  private:
 299   // In general a JavaThread's _terminated field transitions as follows:
 300   //
 301   //   _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
 302   //
 303   // _vm_exited is a special value to cover the case of a JavaThread
 304   // executing native code after the VM itself is terminated.
 305   //
 306   // A JavaThread that fails to JNI attach has these _terminated field transitions:
 307   //   _not_terminated => _thread_terminated
 308   //
 309   volatile TerminatedTypes _terminated;
 310 
 311   jint                  _in_deopt_handler;       // count of deoptimization
 312                                                  // handlers thread is in
 313   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 314   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 315                                                          // never locked) when throwing an exception. Used by interpreter only.
 316 #if INCLUDE_JVMTI
 317   volatile bool         _carrier_thread_suspended;       // Carrier thread is externally suspended
 318   bool                  _is_in_VTMS_transition;          // thread is in virtual thread mount state transition
 319   bool                  _is_in_tmp_VTMS_transition;      // thread is in temporary virtual thread mount state transition
 320 #ifdef ASSERT
 321   bool                  _is_VTMS_transition_disabler;    // thread currently disabled VTMS transitions
 322 #endif
 323 #endif
 324 
 325   // JNI attach states:
 326   enum JNIAttachStates {
 327     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 328     _attaching_via_jni,          // thread is attaching via JNI
 329     _attached_via_jni            // thread has attached via JNI
 330   };
 331 
 332   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 333   // A native thread that is attaching via JNI starts with a value
 334   // of _attaching_via_jni and transitions to _attached_via_jni.
 335   volatile JNIAttachStates _jni_attach_state;
 336 
 337 
 338 #if INCLUDE_JVMCI
 339   // The _pending_* fields below are used to communicate extra information
 340   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 341 
 342   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 343   int       _pending_deoptimization;
 344 
 345   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 346   // before the monitor has been acquired.
 347   bool      _pending_monitorenter;
 348 
 349   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 350   bool      _pending_transfer_to_interpreter;
 351 
 352   // True if in a runtime call from compiled code that will deoptimize
 353   // and re-execute a failed heap allocation in the interpreter.
 354   bool      _in_retryable_allocation;
 355 
 356   // An id of a speculation that JVMCI compiled code can use to further describe and
 357   // uniquely identify the speculative optimization guarded by an uncommon trap.
 358   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 359   jlong     _pending_failed_speculation;
 360 
 361   // These fields are mutually exclusive in terms of live ranges.
 362   union {
 363     // Communicates the pc at which the most recent implicit exception occurred
 364     // from the signal handler to a deoptimization stub.
 365     address   _implicit_exception_pc;
 366 
 367     // Communicates an alternative call target to an i2c stub from a JavaCall .
 368     address   _alternate_call_target;
 369   } _jvmci;
 370 
 371   // The JVMCIRuntime in a JVMCI shared library
 372   JVMCIRuntime* _libjvmci_runtime;
 373 
 374   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 375   jlong*    _jvmci_counters;
 376 
 377   // Fast thread locals for use by JVMCI
 378   jlong      _jvmci_reserved0;
 379   jlong      _jvmci_reserved1;
 380   oop        _jvmci_reserved_oop0;
 381 
 382  public:
 383   static jlong* _jvmci_old_thread_counters;
 384   static void collect_counters(jlong* array, int length);
 385 
 386   bool resize_counters(int current_size, int new_size);
 387 
 388   static bool resize_all_jvmci_counters(int new_size);
 389 
 390   void set_jvmci_reserved_oop0(oop value) {
 391     _jvmci_reserved_oop0 = value;
 392   }
 393 
 394   oop get_jvmci_reserved_oop0() {
 395     return _jvmci_reserved_oop0;
 396   }
 397 
 398   void set_jvmci_reserved0(jlong value) {
 399     _jvmci_reserved0 = value;
 400   }
 401 
 402   jlong get_jvmci_reserved0() {
 403     return _jvmci_reserved0;
 404   }
 405 
 406   void set_jvmci_reserved1(jlong value) {
 407     _jvmci_reserved1 = value;
 408   }
 409 
 410   jlong get_jvmci_reserved1() {
 411     return _jvmci_reserved1;
 412   }
 413 
 414  private:
 415 #endif // INCLUDE_JVMCI
 416 
 417   StackOverflow    _stack_overflow_state;
 418 
 419   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 420   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 421   // code)
 422   volatile oop     _exception_oop;               // Exception thrown in compiled code
 423   volatile address _exception_pc;                // PC where exception happened
 424   volatile address _exception_handler_pc;        // PC for handler of exception
 425   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 426 
 427  private:
 428   // support for JNI critical regions
 429   jint    _jni_active_critical;                  // count of entries into JNI critical region
 430 
 431   // Checked JNI: function name requires exception check
 432   char* _pending_jni_exception_check_fn;
 433 
 434   // For deadlock detection.
 435   int _depth_first_number;
 436 
 437   // JVMTI PopFrame support
 438   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 439   int _popframe_condition;
 440 
 441   // If reallocation of scalar replaced objects fails, we throw OOM
 442   // and during exception propagation, pop the top
 443   // _frames_to_pop_failed_realloc frames, the ones that reference
 444   // failed reallocations.
 445   int _frames_to_pop_failed_realloc;
 446 
 447   ContinuationEntry* _cont_entry;
 448   intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub frame inside the
 449                             // continuation that we know about
 450   int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
 451   // It's signed for error detection.
 452 #ifdef _LP64
 453   int64_t _held_monitor_count;  // used by continuations for fast lock detection
 454   int64_t _jni_monitor_count;
 455 #else
 456   int32_t _held_monitor_count;  // used by continuations for fast lock detection
 457   int32_t _jni_monitor_count;
 458 #endif
 459 
 460 private:
 461 
 462   friend class VMThread;
 463   friend class ThreadWaitTransition;
 464   friend class VM_Exit;
 465 
 466   // Stack watermark barriers.
 467   StackWatermarks _stack_watermarks;
 468 
 469  public:
 470   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
 471 
 472  public:
 473   jlong _scopedValue_hash_table_shift;
 474 
 475   void allocate_scopedValue_hash_table(int count);
 476 
 477  public:
 478   // Constructor
 479   JavaThread();                            // delegating constructor
 480   JavaThread(bool is_attaching_via_jni);   // for main thread and JNI attached threads
 481   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 482   ~JavaThread();
 483 
 484 #ifdef ASSERT
 485   // verify this JavaThread hasn't be published in the Threads::list yet
 486   void verify_not_published();
 487 #endif // ASSERT
 488 
 489   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
 490 
 491   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 492   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 493     _jni_environment.functions = functionTable;
 494   }
 495   struct JNINativeInterface_* get_jni_functions() {
 496     return (struct JNINativeInterface_ *)_jni_environment.functions;
 497   }
 498 
 499   // This function is called at thread creation to allow
 500   // platform specific thread variables to be initialized.
 501   void cache_global_variables();
 502 
 503   // Executes Shutdown.shutdown()
 504   void invoke_shutdown_hooks();
 505 
 506   // Cleanup on thread exit
 507   enum ExitType {
 508     normal_exit,
 509     jni_detach
 510   };
 511   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 512 
 513   void cleanup_failed_attach_current_thread(bool is_daemon);
 514 
 515   // Testers
 516   virtual bool is_Java_thread() const            { return true;  }
 517   virtual bool can_call_java() const             { return true; }
 518 
 519   virtual bool is_active_Java_thread() const {
 520     return on_thread_list() && !is_terminated();
 521   }
 522 
 523   // Thread oop. threadObj() can be NULL for initial JavaThread
 524   // (or for threads attached via JNI)
 525   oop threadObj() const;
 526   void set_threadOopHandles(oop p);
 527   oop vthread() const;
 528   void set_vthread(oop p);
 529   oop scopedValueCache() const;
 530   void set_scopedValueCache(oop p);
 531   void clear_scopedValueBindings();
 532   oop jvmti_vthread() const;
 533   void set_jvmti_vthread(oop p);
 534 
 535   // Prepare thread and add to priority queue.  If a priority is
 536   // not specified, use the priority of the thread object. Threads_lock
 537   // must be held while this function is called.
 538   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
 539 
 540   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
 541   address saved_exception_pc()                   { return _saved_exception_pc; }
 542 
 543   ThreadFunction entry_point() const             { return _entry_point; }
 544 
 545   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
 546   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
 547 
 548   // Last frame anchor routines
 549 
 550   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
 551 
 552   // last_Java_sp
 553   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
 554   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
 555 
 556   // last_Java_pc
 557 
 558   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
 559 
 560   // Safepoint support
 561   inline JavaThreadState thread_state() const;
 562   inline void set_thread_state(JavaThreadState s);
 563   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
 564   inline ThreadSafepointState* safepoint_state() const;
 565   inline void set_safepoint_state(ThreadSafepointState* state);
 566   inline bool is_at_poll_safepoint();
 567 
 568   // JavaThread termination and lifecycle support:
 569   void smr_delete();
 570   bool on_thread_list() const { return _on_thread_list; }
 571   void set_on_thread_list() { _on_thread_list = true; }
 572 
 573   // thread has called JavaThread::exit(), thread's GC barrier is detached
 574   // or thread is terminated
 575   bool is_exiting() const;
 576   // thread's GC barrier is NOT detached and thread is NOT terminated
 577   bool is_oop_safe() const;
 578   // thread is terminated (no longer on the threads list); the thread must
 579   // be protected by a ThreadsListHandle to avoid potential crashes.
 580   bool check_is_terminated(TerminatedTypes l_terminated) const {
 581     return l_terminated == _thread_terminated || l_terminated == _vm_exited;
 582   }
 583   bool is_terminated() const;
 584   void set_terminated(TerminatedTypes t);
 585 
 586   void block_if_vm_exited();
 587 
 588   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
 589   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
 590 
 591   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
 592   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
 593 
 594   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
 595 
 596   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
 597 
 598   // Continuation support
 599   oop get_continuation() const;
 600   ContinuationEntry* last_continuation() const { return _cont_entry; }
 601   void set_cont_fastpath(intptr_t* x)          { _cont_fastpath = x; }
 602   void push_cont_fastpath(intptr_t* sp)        { if (sp > _cont_fastpath) _cont_fastpath = sp; }
 603   void set_cont_fastpath_thread_state(bool x)  { _cont_fastpath_thread_state = (int)x; }
 604   intptr_t* raw_cont_fastpath() const          { return _cont_fastpath; }
 605   bool cont_fastpath() const                   { return _cont_fastpath == NULL && _cont_fastpath_thread_state != 0; }
 606   bool cont_fastpath_thread_state() const      { return _cont_fastpath_thread_state != 0; }
 607 
 608   void inc_held_monitor_count(int i = 1, bool jni = false);
 609   void dec_held_monitor_count(int i = 1, bool jni = false);
 610 
 611   int64_t held_monitor_count() { return (int64_t)_held_monitor_count; }
 612   int64_t jni_monitor_count()  { return (int64_t)_jni_monitor_count;  }
 613   void clear_jni_monitor_count() { _jni_monitor_count = 0;   }
 614 
 615   inline bool is_vthread_mounted() const;
 616   inline const ContinuationEntry* vthread_continuation() const;
 617 
 618  private:
 619   DEBUG_ONLY(void verify_frame_info();)
 620 
 621   // Support for thread handshake operations
 622   HandshakeState _handshake;
 623  public:
 624   HandshakeState* handshake_state() { return &_handshake; }
 625 
 626   // A JavaThread can always safely operate on it self and other threads
 627   // can do it safely if they are the active handshaker.
 628   bool is_handshake_safe_for(Thread* th) const {
 629     return _handshake.active_handshaker() == th || this == th;
 630   }
 631 
 632   // Suspend/resume support for JavaThread
 633   // higher-level suspension/resume logic called by the public APIs
 634   bool java_suspend();
 635   bool java_resume();
 636   bool is_suspended()     { return _handshake.is_suspended(); }
 637 
 638   // Check for async exception in addition to safepoint.
 639   static void check_special_condition_for_native_trans(JavaThread *thread);
 640 
 641   // Synchronize with another thread that is deoptimizing objects of the
 642   // current thread, i.e. reverts optimizations based on escape analysis.
 643   void wait_for_object_deoptimization();
 644 
 645 #if INCLUDE_JVMTI
 646   inline void set_carrier_thread_suspended();
 647   inline void clear_carrier_thread_suspended();
 648 
 649   bool is_carrier_thread_suspended() const {
 650     return _carrier_thread_suspended;
 651   }
 652 
 653   bool is_in_VTMS_transition() const             { return _is_in_VTMS_transition; }
 654   bool is_in_tmp_VTMS_transition() const         { return _is_in_tmp_VTMS_transition; }
 655   bool is_in_any_VTMS_transition() const         { return _is_in_VTMS_transition || _is_in_tmp_VTMS_transition; }
 656 
 657   void set_is_in_VTMS_transition(bool val);
 658   void toggle_is_in_tmp_VTMS_transition()        { _is_in_tmp_VTMS_transition = !_is_in_tmp_VTMS_transition; };
 659 
 660 #ifdef ASSERT
 661   bool is_VTMS_transition_disabler() const       { return _is_VTMS_transition_disabler; }
 662   void set_is_VTMS_transition_disabler(bool val);
 663 #endif
 664 #endif
 665 
 666   // Support for object deoptimization and JFR suspension
 667   void handle_special_runtime_exit_condition();
 668   bool has_special_runtime_exit_condition() {
 669     return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
 670   }
 671 
 672   // Fast-locking support
 673   bool is_lock_owned(address adr) const;
 674   bool is_lock_owned_current(address adr) const; // virtual if mounted, otherwise whole thread
 675   bool is_lock_owned_carrier(address adr) const;
 676 
 677   // Accessors for vframe array top
 678   // The linked list of vframe arrays are sorted on sp. This means when we
 679   // unpack the head must contain the vframe array to unpack.
 680   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
 681   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
 682 
 683   // Side structure for deferring update of java frame locals until deopt occurs
 684   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
 685   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
 686 
 687   // These only really exist to make debugging deopt problems simpler
 688 
 689   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
 690   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
 691 
 692   // The special resourceMark used during deoptimization
 693 
 694   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
 695   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
 696 
 697   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
 698   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
 699 
 700   Method*    callee_target() const               { return _callee_target; }
 701   void set_callee_target  (Method* x)          { _callee_target   = x; }
 702 
 703   // Oop results of vm runtime calls
 704   oop  vm_result() const                         { return _vm_result; }
 705   void set_vm_result  (oop x)                    { _vm_result   = x; }
 706 
 707   Metadata*    vm_result_2() const               { return _vm_result_2; }
 708   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
 709 
 710   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
 711   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
 712 
 713 #if INCLUDE_JVMCI
 714   int  pending_deoptimization() const             { return _pending_deoptimization; }
 715   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
 716   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
 717   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
 718   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
 719   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
 720   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
 721   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
 722   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
 723 
 724   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
 725   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
 726 
 727   JVMCIRuntime* libjvmci_runtime() const          { return _libjvmci_runtime; }
 728   void set_libjvmci_runtime(JVMCIRuntime* rt) {
 729     assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
 730     _libjvmci_runtime = rt;
 731   }
 732 #endif // INCLUDE_JVMCI
 733 
 734   // Exception handling for compiled methods
 735   oop      exception_oop() const;
 736   address  exception_pc() const                  { return _exception_pc; }
 737   address  exception_handler_pc() const          { return _exception_handler_pc; }
 738   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
 739 
 740   void set_exception_oop(oop o);
 741   void set_exception_pc(address a)               { _exception_pc = a; }
 742   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
 743   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
 744 
 745   void clear_exception_oop_and_pc() {
 746     set_exception_oop(NULL);
 747     set_exception_pc(NULL);
 748   }
 749 
 750   // Check if address is in the usable part of the stack (excludes protected
 751   // guard pages). Can be applied to any thread and is an approximation for
 752   // using is_in_live_stack when the query has to happen from another thread.
 753   bool is_in_usable_stack(address adr) const {
 754     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
 755   }
 756 
 757   // Misc. accessors/mutators
 758   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
 759   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
 760   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
 761 
 762   static ByteSize scopedValueCache_offset()       { return byte_offset_of(JavaThread, _scopedValueCache); }
 763 
 764   // For assembly stub generation
 765   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
 766   static ByteSize vthread_offset()               { return byte_offset_of(JavaThread, _vthread); }
 767   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
 768   static ByteSize pending_jni_exception_check_fn_offset() {
 769     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
 770   }
 771   static ByteSize last_Java_sp_offset() {
 772     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
 773   }
 774   static ByteSize last_Java_pc_offset() {
 775     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
 776   }
 777   static ByteSize frame_anchor_offset() {
 778     return byte_offset_of(JavaThread, _anchor);
 779   }
 780   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
 781   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
 782   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
 783   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
 784   static ByteSize polling_word_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_word);}
 785   static ByteSize polling_page_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_page);}
 786   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
 787   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
 788 #if INCLUDE_JVMCI
 789   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
 790   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
 791   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
 792   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
 793   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
 794   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
 795 #endif // INCLUDE_JVMCI
 796   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
 797   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
 798   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
 799   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
 800 
 801   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
 802 
 803   // StackOverflow offsets
 804   static ByteSize stack_overflow_limit_offset()  {
 805     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
 806   }
 807   static ByteSize stack_guard_state_offset()     {
 808     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
 809   }
 810   static ByteSize reserved_stack_activation_offset() {
 811     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
 812   }
 813   static ByteSize shadow_zone_safe_limit()  {
 814     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
 815   }
 816   static ByteSize shadow_zone_growth_watermark()  {
 817     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
 818   }
 819 
 820   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
 821 
 822   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
 823   static ByteSize should_post_on_exceptions_flag_offset() {
 824     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
 825   }
 826   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
 827   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
 828 
 829   static ByteSize cont_entry_offset()         { return byte_offset_of(JavaThread, _cont_entry); }
 830   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
 831   static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
 832 
 833   // Returns the jni environment for this thread
 834   JNIEnv* jni_environment()                      { return &_jni_environment; }
 835 
 836   // Returns the current thread as indicated by the given JNIEnv.
 837   // We don't assert it is Thread::current here as that is done at the
 838   // external JNI entry points where the JNIEnv is passed into the VM.
 839   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
 840     JavaThread* current = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
 841     // We can't normally get here in a thread that has completed its
 842     // execution and so "is_terminated", except when the call is from
 843     // AsyncGetCallTrace, which can be triggered by a signal at any point in
 844     // a thread's lifecycle. A thread is also considered terminated if the VM
 845     // has exited, so we have to check this and block in case this is a daemon
 846     // thread returning to the VM (the JNI DirectBuffer entry points rely on
 847     // this).
 848     if (current->is_terminated()) {
 849       current->block_if_vm_exited();
 850     }
 851     return current;
 852   }
 853 
 854   // JNI critical regions. These can nest.
 855   bool in_critical()    { return _jni_active_critical > 0; }
 856   bool in_last_critical()  { return _jni_active_critical == 1; }
 857   inline void enter_critical();
 858   void exit_critical() {
 859     assert(Thread::current() == this, "this must be current thread");
 860     _jni_active_critical--;
 861     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
 862   }
 863 
 864   // Checked JNI: is the programmer required to check for exceptions, if so specify
 865   // which function name. Returning to a Java frame should implicitly clear the
 866   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
 867   // VM->Java transitions are not cleared, it is expected that JNI code enclosed
 868   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
 869   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
 870   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
 871   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
 872   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
 873 
 874   // For deadlock detection
 875   int depth_first_number() { return _depth_first_number; }
 876   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
 877 
 878  private:
 879   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
 880 
 881  public:
 882   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
 883   void add_monitor_chunk(MonitorChunk* chunk);
 884   void remove_monitor_chunk(MonitorChunk* chunk);
 885   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
 886   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
 887   void dec_in_deopt_handler() {
 888     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
 889     if (_in_deopt_handler > 0) { // robustness
 890       _in_deopt_handler--;
 891     }
 892   }
 893 
 894  private:
 895   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
 896 
 897   // factor out low-level mechanics for use in both normal and error cases
 898   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
 899 
 900  public:
 901 
 902   // Frame iteration; calls the function f for all frames on the stack
 903   void frames_do(void f(frame*, const RegisterMap*));
 904 
 905   // Memory operations
 906   void oops_do_frames(OopClosure* f, CodeBlobClosure* cf);
 907   void oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf);
 908 
 909   // GC operations
 910   virtual void nmethods_do(CodeBlobClosure* cf);
 911 
 912   // RedefineClasses Support
 913   void metadata_do(MetadataClosure* f);
 914 
 915   // Debug method asserting thread states are correct during a handshake operation.
 916   DEBUG_ONLY(void verify_states_for_handshake();)
 917 
 918   // Misc. operations
 919   const char* name() const;
 920   const char* type_name() const { return "JavaThread"; }
 921   static const char* name_for(oop thread_obj);
 922 
 923   void print_on(outputStream* st, bool print_extended_info) const;
 924   void print_on(outputStream* st) const { print_on(st, false); }
 925   void print() const;
 926   void print_thread_state_on(outputStream*) const;
 927   const char* thread_state_name() const;
 928   void print_on_error(outputStream* st, char* buf, int buflen) const;
 929   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
 930   void verify();
 931 
 932   // Accessing frames
 933   frame last_frame() {
 934     _anchor.make_walkable();
 935     return pd_last_frame();
 936   }
 937   javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
 938 
 939   frame carrier_last_frame(RegisterMap* reg_map);
 940   javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
 941 
 942   frame vthread_last_frame();
 943   javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
 944 
 945   frame platform_thread_last_frame(RegisterMap* reg_map);
 946   javaVFrame*  platform_thread_last_java_vframe(RegisterMap* reg_map) {
 947     return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
 948   }
 949 
 950   javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
 951 
 952   // Returns method at 'depth' java or native frames down the stack
 953   // Used for security checks
 954   Klass* security_get_caller_class(int depth);
 955 
 956   // Print stack trace in external format
 957   void print_stack_on(outputStream* st);
 958   void print_stack() { print_stack_on(tty); }
 959 
 960   // Print stack traces in various internal formats
 961   void trace_stack()                             PRODUCT_RETURN;
 962   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
 963   void trace_frames()                            PRODUCT_RETURN;
 964 
 965   // Print an annotated view of the stack frames
 966   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
 967   void validate_frame_layout() {
 968     print_frame_layout(0, true);
 969   }
 970 
 971   // Function for testing deoptimization
 972   void deoptimize();
 973   void make_zombies();
 974 
 975   void deoptimize_marked_methods();
 976 
 977  public:
 978   // Returns the running thread as a JavaThread
 979   static JavaThread* current() {
 980     return JavaThread::cast(Thread::current());
 981   }
 982 
 983   // Returns the current thread as a JavaThread, or NULL if not attached
 984   static inline JavaThread* current_or_null();
 985 
 986   // Casts
 987   static JavaThread* cast(Thread* t) {
 988     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
 989     return static_cast<JavaThread*>(t);
 990   }
 991 
 992   static const JavaThread* cast(const Thread* t) {
 993     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
 994     return static_cast<const JavaThread*>(t);
 995   }
 996 
 997   // Returns the active Java thread.  Do not use this if you know you are calling
 998   // from a JavaThread, as it's slower than JavaThread::current.  If called from
 999   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1000   // operation.  You may not want that either.
1001   static JavaThread* active();
1002 
1003  protected:
1004   virtual void pre_run();
1005   virtual void run();
1006   void thread_main_inner();
1007   virtual void post_run();
1008 
1009  public:
1010   // Thread local information maintained by JVMTI.
1011   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1012   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1013   // getter is used to get this JavaThread's JvmtiThreadState if it has
1014   // one which means NULL can be returned. JvmtiThreadState::state_for()
1015   // is used to get the specified JavaThread's JvmtiThreadState if it has
1016   // one or it allocates a new JvmtiThreadState for the JavaThread and
1017   // returns it. JvmtiThreadState::state_for() will return NULL only if
1018   // the specified JavaThread is exiting.
1019   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1020   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1021 
1022 #if INCLUDE_JVMTI
1023   // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1024   JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1025 #endif
1026 
1027   // JVMTI PopFrame support
1028   // Setting and clearing popframe_condition
1029   // All of these enumerated values are bits. popframe_pending
1030   // indicates that a PopFrame() has been requested and not yet been
1031   // completed. popframe_processing indicates that that PopFrame() is in
1032   // the process of being completed. popframe_force_deopt_reexecution_bit
1033   // indicates that special handling is required when returning to a
1034   // deoptimized caller.
1035   enum PopCondition {
1036     popframe_inactive                      = 0x00,
1037     popframe_pending_bit                   = 0x01,
1038     popframe_processing_bit                = 0x02,
1039     popframe_force_deopt_reexecution_bit   = 0x04
1040   };
1041   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1042   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1043   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1044   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1045   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1046   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1047   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1048   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1049 
1050   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1051   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1052   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1053 
1054   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1055   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1056   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1057 
1058  private:
1059   // Saved incoming arguments to popped frame.
1060   // Used only when popped interpreted frame returns to deoptimized frame.
1061   void*    _popframe_preserved_args;
1062   int      _popframe_preserved_args_size;
1063 
1064  public:
1065   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1066   void* popframe_preserved_args();
1067   ByteSize popframe_preserved_args_size();
1068   WordSize popframe_preserved_args_size_in_words();
1069   void  popframe_free_preserved_args();
1070 
1071 
1072  private:
1073   JvmtiThreadState *_jvmti_thread_state;
1074 
1075   // Used by the interpreter in fullspeed mode for frame pop, method
1076   // entry, method exit and single stepping support. This field is
1077   // only set to non-zero at a safepoint or using a direct handshake
1078   // (see EnterInterpOnlyModeClosure).
1079   // It can be set to zero asynchronously to this threads execution (i.e., without
1080   // safepoint/handshake or a lock) so we have to be very careful.
1081   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1082   int               _interp_only_mode;
1083 
1084  public:
1085   // used by the interpreter for fullspeed debugging support (see above)
1086   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1087   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1088   int get_interp_only_mode()                { return _interp_only_mode; }
1089   int set_interp_only_mode(int val)         { return _interp_only_mode = val; }
1090   void increment_interp_only_mode()         { ++_interp_only_mode; }
1091   void decrement_interp_only_mode()         { --_interp_only_mode; }
1092 
1093   // support for cached flag that indicates whether exceptions need to be posted for this thread
1094   // if this is false, we can avoid deoptimizing when events are thrown
1095   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1096  private:
1097   int    _should_post_on_exceptions_flag;
1098 
1099  public:
1100   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1101   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1102 
1103  private:
1104   ThreadStatistics *_thread_stat;
1105 
1106  public:
1107   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1108 
1109   // Return a blocker object for which this thread is blocked parking.
1110   oop current_park_blocker();
1111 
1112  private:
1113   static size_t _stack_size_at_create;
1114 
1115  public:
1116   static inline size_t stack_size_at_create(void) {
1117     return _stack_size_at_create;
1118   }
1119   static inline void set_stack_size_at_create(size_t value) {
1120     _stack_size_at_create = value;
1121   }
1122 
1123   // Machine dependent stuff
1124 #include OS_CPU_HEADER(javaThread)
1125 
1126   // JSR166 per-thread parker
1127  private:
1128   Parker _parker;
1129  public:
1130   Parker* parker() { return &_parker; }
1131 
1132  public:
1133   // clearing/querying jni attach status
1134   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1135   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1136   inline void set_done_attaching_via_jni();
1137 
1138   // Stack dump assistance:
1139   // Track the class we want to initialize but for which we have to wait
1140   // on its init_lock() because it is already being initialized.
1141   void set_class_to_be_initialized(InstanceKlass* k);
1142   InstanceKlass* class_to_be_initialized() const;
1143 
1144 private:
1145   InstanceKlass* _class_to_be_initialized;
1146 
1147   // java.lang.Thread.sleep support
1148   ParkEvent * _SleepEvent;
1149 public:
1150   bool sleep(jlong millis);
1151 
1152   // java.lang.Thread interruption support
1153   void interrupt();
1154   bool is_interrupted(bool clear_interrupted);
1155 
1156   static OopStorage* thread_oop_storage();
1157 
1158   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1159 
1160   // Helper function to create the java.lang.Thread object for a
1161   // VM-internal thread. The thread will have the given name, be
1162   // part of the System ThreadGroup and if is_visible is true will be
1163   // discoverable via the system ThreadGroup.
1164   static Handle create_system_thread_object(const char* name, bool is_visible, TRAPS);
1165 
1166   // Helper function to start a VM-internal daemon thread.
1167   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1168   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1169                                     Handle thread_oop, ThreadPriority prio);
1170 
1171   // Helper function to do vm_exit_on_initialization for osthread
1172   // resource allocation failure.
1173   static void vm_exit_on_osthread_failure(JavaThread* thread);
1174 
1175   // AsyncGetCallTrace support
1176   inline bool in_asgct(void) {return _in_asgct;}
1177   inline void set_in_asgct(bool value) {_in_asgct = value;}
1178 
1179   // Deferred OopHandle release support
1180  private:
1181   // List of OopHandles to be released - guarded by the Service_lock.
1182   static OopHandleList* _oop_handle_list;
1183   // Add our OopHandles to the list for the service thread to release.
1184   void add_oop_handles_for_release();
1185   // Called by the ServiceThread to release the OopHandles.
1186   static void release_oop_handles();
1187   // Called by the ServiceThread to poll if there are any OopHandles to release.
1188   // Called when holding the Service_lock.
1189   static bool has_oop_handles_to_release() {
1190     return _oop_handle_list != nullptr;
1191   }
1192 };
1193 
1194 inline JavaThread* JavaThread::current_or_null() {
1195   Thread* current = Thread::current_or_null();
1196   return current != nullptr ? JavaThread::cast(current) : nullptr;
1197 }
1198 
1199 class UnlockFlagSaver {
1200   private:
1201     JavaThread* _thread;
1202     bool _do_not_unlock;
1203   public:
1204     UnlockFlagSaver(JavaThread* t) {
1205       _thread = t;
1206       _do_not_unlock = t->do_not_unlock_if_synchronized();
1207       t->set_do_not_unlock_if_synchronized(false);
1208     }
1209     ~UnlockFlagSaver() {
1210       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1211     }
1212 };
1213 
1214 class JNIHandleMark : public StackObj {
1215   JavaThread* _thread;
1216  public:
1217   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1218     thread->push_jni_handle_block();
1219   }
1220   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1221 };
1222 
1223 #endif // SHARE_RUNTIME_JAVATHREAD_HPP