1 /*
   2  * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #ifndef SHARE_RUNTIME_JAVATHREAD_HPP
  27 #define SHARE_RUNTIME_JAVATHREAD_HPP
  28 
  29 #include "jni.h"
  30 #include "memory/allocation.hpp"
  31 #include "oops/oop.hpp"
  32 #include "oops/oopHandle.hpp"
  33 #include "runtime/frame.hpp"
  34 #include "runtime/globals.hpp"
  35 #include "runtime/handshake.hpp"
  36 #include "runtime/javaFrameAnchor.hpp"
  37 #include "runtime/park.hpp"
  38 #include "runtime/safepointMechanism.hpp"
  39 #include "runtime/stackWatermarkSet.hpp"
  40 #include "runtime/stackOverflow.hpp"
  41 #include "runtime/thread.hpp"
  42 #include "runtime/threadHeapSampler.hpp"
  43 #include "runtime/threadStatisticalInfo.hpp"
  44 #include "utilities/exceptions.hpp"
  45 #include "utilities/globalDefinitions.hpp"
  46 #include "utilities/macros.hpp"
  47 #if INCLUDE_JFR
  48 #include "jfr/support/jfrThreadExtension.hpp"
  49 #endif
  50 
  51 class AsyncExceptionHandshake;
  52 class ContinuationEntry;
  53 class DeoptResourceMark;
  54 class JNIHandleBlock;
  55 class JVMCIRuntime;
  56 
  57 class JvmtiDeferredUpdates;
  58 class JvmtiSampledObjectAllocEventCollector;
  59 class JvmtiThreadState;
  60 
  61 class Metadata;
  62 class OopStorage;
  63 class OSThread;
  64 
  65 class ThreadsList;
  66 class ThreadSafepointState;
  67 class ThreadStatistics;
  68 
  69 class vframeArray;
  70 class vframe;
  71 class javaVFrame;
  72 
  73 class JavaThread;
  74 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
  75 
  76 class JavaThread: public Thread {
  77   friend class VMStructs;
  78   friend class JVMCIVMStructs;
  79   friend class WhiteBox;
  80   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
  81   friend class HandshakeState;
  82   friend class Continuation;
  83   friend class Threads;
  84  private:
  85   bool           _in_asgct;                      // Is set when this JavaThread is handling ASGCT call
  86   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
  87   OopHandle      _threadObj;                     // The Java level thread object
  88   OopHandle      _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
  89   OopHandle      _jvmti_vthread;
  90   OopHandle      _extentLocalCache;
  91 
  92   static OopStorage* _thread_oop_storage;
  93 
  94 #ifdef ASSERT
  95  private:
  96   int _java_call_counter;
  97 
  98  public:
  99   int  java_call_counter()                       { return _java_call_counter; }
 100   void inc_java_call_counter()                   { _java_call_counter++; }
 101   void dec_java_call_counter() {
 102     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 103     _java_call_counter--;
 104   }
 105  private:  // restore original namespace restriction
 106 #endif  // ifdef ASSERT
 107 
 108   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 109 
 110   ThreadFunction _entry_point;
 111 
 112   JNIEnv        _jni_environment;
 113 
 114   // Deopt support
 115   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 116 
 117   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 118   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 119   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 120   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
 121   // will be carried out as soon as possible which, in most cases, is just before deoptimization of
 122   // the frame, when control returns to it.
 123   JvmtiDeferredUpdates* _jvmti_deferred_updates;
 124 
 125   // Handshake value for fixing 6243940. We need a place for the i2c
 126   // adapter to store the callee Method*. This value is NEVER live
 127   // across a gc point so it does NOT have to be gc'd
 128   // The handshake is open ended since we can't be certain that it will
 129   // be NULLed. This is because we rarely ever see the race and end up
 130   // in handle_wrong_method which is the backend of the handshake. See
 131   // code in i2c adapters and handle_wrong_method.
 132 
 133   Method*       _callee_target;
 134 
 135   // Used to pass back results to the interpreter or generated code running Java code.
 136   oop           _vm_result;    // oop result is GC-preserved
 137   Metadata*     _vm_result_2;  // non-oop result
 138   oop           _return_buffered_value; // buffered value being returned
 139 
 140   // See ReduceInitialCardMarks: this holds the precise space interval of
 141   // the most recent slow path allocation for which compiled code has
 142   // elided card-marks for performance along the fast-path.
 143   MemRegion     _deferred_card_mark;
 144 
 145   ObjectMonitor* volatile _current_pending_monitor;     // ObjectMonitor this thread is waiting to lock
 146   bool           _current_pending_monitor_is_from_java; // locking is from Java code
 147   ObjectMonitor* volatile _current_waiting_monitor;     // ObjectMonitor on which this thread called Object.wait()
 148 
 149   // Active_handles points to a block of handles
 150   JNIHandleBlock* _active_handles;
 151 
 152   // One-element thread local free list
 153   JNIHandleBlock* _free_handle_block;
 154 
 155  public:
 156   volatile intptr_t _Stalled;
 157 
 158   // For tracking the heavyweight monitor the thread is pending on.
 159   ObjectMonitor* current_pending_monitor() {
 160     // Use Atomic::load() to prevent data race between concurrent modification and
 161     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 162     // Especially, reloading pointer from thread after NULL check must be prevented.
 163     return Atomic::load(&_current_pending_monitor);
 164   }
 165   void set_current_pending_monitor(ObjectMonitor* monitor) {
 166     Atomic::store(&_current_pending_monitor, monitor);
 167   }
 168   void set_current_pending_monitor_is_from_java(bool from_java) {
 169     _current_pending_monitor_is_from_java = from_java;
 170   }
 171   bool current_pending_monitor_is_from_java() {
 172     return _current_pending_monitor_is_from_java;
 173   }
 174   ObjectMonitor* current_waiting_monitor() {
 175     // See the comment in current_pending_monitor() above.
 176     return Atomic::load(&_current_waiting_monitor);
 177   }
 178   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 179     Atomic::store(&_current_waiting_monitor, monitor);
 180   }
 181 
 182   // JNI handle support
 183   JNIHandleBlock* active_handles() const         { return _active_handles; }
 184   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 185   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 186   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 187 
 188   void push_jni_handle_block();
 189   void pop_jni_handle_block();
 190 
 191  private:
 192   MonitorChunk* _monitor_chunks;              // Contains the off stack monitors
 193                                               // allocated during deoptimization
 194                                               // and by JNI_MonitorEnter/Exit
 195 
 196   enum SuspendFlags {
 197     // NOTE: avoid using the sign-bit as cc generates different test code
 198     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 199     _trace_flag             = 0x00000004U, // call tracing backend
 200     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 201   };
 202 
 203   // various suspension related flags - atomically updated
 204   volatile uint32_t _suspend_flags;
 205 
 206   inline void set_suspend_flag(SuspendFlags f);
 207   inline void clear_suspend_flag(SuspendFlags f);
 208 
 209  public:
 210   inline void set_trace_flag();
 211   inline void clear_trace_flag();
 212   inline void set_obj_deopt_flag();
 213   inline void clear_obj_deopt_flag();
 214   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 215   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 216 
 217   // Asynchronous exception support
 218  private:
 219   friend class InstallAsyncExceptionHandshake;
 220   friend class AsyncExceptionHandshake;
 221   friend class HandshakeState;
 222 
 223   void install_async_exception(AsyncExceptionHandshake* aec = NULL);
 224   void handle_async_exception(oop java_throwable);
 225  public:
 226   bool has_async_exception_condition(bool ThreadDeath_only = false);
 227   inline void set_pending_unsafe_access_error();
 228   static void send_async_exception(JavaThread* jt, oop java_throwable);
 229 
 230   class NoAsyncExceptionDeliveryMark : public StackObj {
 231     friend JavaThread;
 232     JavaThread *_target;
 233     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 234     inline ~NoAsyncExceptionDeliveryMark();
 235   };
 236 
 237   // Safepoint support
 238  public:                                                        // Expose _thread_state for SafeFetchInt()
 239   volatile JavaThreadState _thread_state;
 240  private:
 241   SafepointMechanism::ThreadData _poll_data;
 242   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 243   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 244   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 245 #ifdef ASSERT
 246   // Debug support for checking if code allows safepoints or not.
 247   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 248   // mutex, or blocking on an object synchronizer (Java locking).
 249   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 250   // the above cases. The class NoSafepointVerifier is used to set this counter.
 251   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 252 
 253  public:
 254   void inc_no_safepoint_count() { _no_safepoint_count++; }
 255   void dec_no_safepoint_count() { _no_safepoint_count--; }
 256 #endif // ASSERT
 257  public:
 258   // These functions check conditions before possibly going to a safepoint.
 259   // including NoSafepointVerifier.
 260   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 261   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 262 
 263 #ifdef ASSERT
 264  private:
 265   volatile uint64_t _visited_for_critical_count;
 266 
 267  public:
 268   void set_visited_for_critical_count(uint64_t safepoint_id) {
 269     assert(_visited_for_critical_count == 0, "Must be reset before set");
 270     assert((safepoint_id & 0x1) == 1, "Must be odd");
 271     _visited_for_critical_count = safepoint_id;
 272   }
 273   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 274     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 275     _visited_for_critical_count = 0;
 276   }
 277   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 278     return _visited_for_critical_count == safepoint_id;
 279   }
 280 #endif // ASSERT
 281 
 282   // JavaThread termination support
 283  public:
 284   enum TerminatedTypes {
 285     _not_terminated = 0xDEAD - 3,
 286     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 287     _thread_gc_barrier_detached,                 // thread's GC barrier has been detached
 288     _thread_terminated,                          // JavaThread is removed from thread list
 289     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 290                                                  // only VM_Exit can set _vm_exited
 291   };
 292 
 293  private:
 294   // In general a JavaThread's _terminated field transitions as follows:
 295   //
 296   //   _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
 297   //
 298   // _vm_exited is a special value to cover the case of a JavaThread
 299   // executing native code after the VM itself is terminated.
 300   //
 301   // A JavaThread that fails to JNI attach has these _terminated field transitions:
 302   //   _not_terminated => _thread_terminated
 303   //
 304   volatile TerminatedTypes _terminated;
 305 
 306   jint                  _in_deopt_handler;       // count of deoptimization
 307                                                  // handlers thread is in
 308   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 309   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 310                                                          // never locked) when throwing an exception. Used by interpreter only.
 311 #if INCLUDE_JVMTI
 312   volatile bool         _carrier_thread_suspended;       // Carrier thread is externally suspended
 313   bool                  _is_in_VTMS_transition;          // thread is in virtual thread mount state transition
 314 #ifdef ASSERT
 315   bool                  _is_VTMS_transition_disabler;    // thread currently disabled VTMS transitions
 316 #endif
 317 #endif
 318 
 319   // JNI attach states:
 320   enum JNIAttachStates {
 321     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 322     _attaching_via_jni,          // thread is attaching via JNI
 323     _attached_via_jni            // thread has attached via JNI
 324   };
 325 
 326   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 327   // A native thread that is attaching via JNI starts with a value
 328   // of _attaching_via_jni and transitions to _attached_via_jni.
 329   volatile JNIAttachStates _jni_attach_state;
 330 
 331 
 332 #if INCLUDE_JVMCI
 333   // The _pending_* fields below are used to communicate extra information
 334   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 335 
 336   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 337   int       _pending_deoptimization;
 338 
 339   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 340   // before the monitor has been acquired.
 341   bool      _pending_monitorenter;
 342 
 343   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 344   bool      _pending_transfer_to_interpreter;
 345 
 346   // True if in a runtime call from compiled code that will deoptimize
 347   // and re-execute a failed heap allocation in the interpreter.
 348   bool      _in_retryable_allocation;
 349 
 350   // An id of a speculation that JVMCI compiled code can use to further describe and
 351   // uniquely identify the speculative optimization guarded by an uncommon trap.
 352   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 353   jlong     _pending_failed_speculation;
 354 
 355   // These fields are mutually exclusive in terms of live ranges.
 356   union {
 357     // Communicates the pc at which the most recent implicit exception occurred
 358     // from the signal handler to a deoptimization stub.
 359     address   _implicit_exception_pc;
 360 
 361     // Communicates an alternative call target to an i2c stub from a JavaCall .
 362     address   _alternate_call_target;
 363   } _jvmci;
 364 
 365   // The JVMCIRuntime in a JVMCI shared library
 366   JVMCIRuntime* _libjvmci_runtime;
 367 
 368   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 369   jlong*    _jvmci_counters;
 370 
 371   // Fast thread locals for use by JVMCI
 372   jlong      _jvmci_reserved0;
 373   jlong      _jvmci_reserved1;
 374   oop        _jvmci_reserved_oop0;
 375 
 376  public:
 377   static jlong* _jvmci_old_thread_counters;
 378   static void collect_counters(jlong* array, int length);
 379 
 380   bool resize_counters(int current_size, int new_size);
 381 
 382   static bool resize_all_jvmci_counters(int new_size);
 383 
 384   void set_jvmci_reserved_oop0(oop value) {
 385     _jvmci_reserved_oop0 = value;
 386   }
 387 
 388   oop get_jvmci_reserved_oop0() {
 389     return _jvmci_reserved_oop0;
 390   }
 391 
 392   void set_jvmci_reserved0(jlong value) {
 393     _jvmci_reserved0 = value;
 394   }
 395 
 396   jlong get_jvmci_reserved0() {
 397     return _jvmci_reserved0;
 398   }
 399 
 400   void set_jvmci_reserved1(jlong value) {
 401     _jvmci_reserved1 = value;
 402   }
 403 
 404   jlong get_jvmci_reserved1() {
 405     return _jvmci_reserved1;
 406   }
 407 
 408  private:
 409 #endif // INCLUDE_JVMCI
 410 
 411   StackOverflow    _stack_overflow_state;
 412 
 413   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 414   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 415   // code)
 416   volatile oop     _exception_oop;               // Exception thrown in compiled code
 417   volatile address _exception_pc;                // PC where exception happened
 418   volatile address _exception_handler_pc;        // PC for handler of exception
 419   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 420 
 421  private:
 422   // support for JNI critical regions
 423   jint    _jni_active_critical;                  // count of entries into JNI critical region
 424 
 425   // Checked JNI: function name requires exception check
 426   char* _pending_jni_exception_check_fn;
 427 
 428   // For deadlock detection.
 429   int _depth_first_number;
 430 
 431   // JVMTI PopFrame support
 432   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 433   int _popframe_condition;
 434 
 435   // If reallocation of scalar replaced objects fails, we throw OOM
 436   // and during exception propagation, pop the top
 437   // _frames_to_pop_failed_realloc frames, the ones that reference
 438   // failed reallocations.
 439   int _frames_to_pop_failed_realloc;
 440 
 441   ContinuationEntry* _cont_entry;
 442   intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub frame inside the
 443                             // continuation that we know about
 444   int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
 445   // It's signed for error detection.
 446 #ifdef _LP64
 447   int64_t _held_monitor_count;  // used by continuations for fast lock detection
 448   int64_t _jni_monitor_count;
 449 #else
 450   int32_t _held_monitor_count;  // used by continuations for fast lock detection
 451   int32_t _jni_monitor_count;
 452 #endif
 453 
 454 private:
 455 
 456   friend class VMThread;
 457   friend class ThreadWaitTransition;
 458   friend class VM_Exit;
 459 
 460   // Stack watermark barriers.
 461   StackWatermarks _stack_watermarks;
 462 
 463  public:
 464   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
 465 
 466  public:
 467   jlong _extentLocal_hash_table_shift;
 468 
 469   void allocate_extentLocal_hash_table(int count);
 470 
 471  public:
 472   // Constructor
 473   JavaThread();                            // delegating constructor
 474   JavaThread(bool is_attaching_via_jni);   // for main thread and JNI attached threads
 475   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 476   ~JavaThread();
 477 
 478 #ifdef ASSERT
 479   // verify this JavaThread hasn't be published in the Threads::list yet
 480   void verify_not_published();
 481 #endif // ASSERT
 482 
 483   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
 484 
 485   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 486   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 487     _jni_environment.functions = functionTable;
 488   }
 489   struct JNINativeInterface_* get_jni_functions() {
 490     return (struct JNINativeInterface_ *)_jni_environment.functions;
 491   }
 492 
 493   // This function is called at thread creation to allow
 494   // platform specific thread variables to be initialized.
 495   void cache_global_variables();
 496 
 497   // Executes Shutdown.shutdown()
 498   void invoke_shutdown_hooks();
 499 
 500   // Cleanup on thread exit
 501   enum ExitType {
 502     normal_exit,
 503     jni_detach
 504   };
 505   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 506 
 507   void cleanup_failed_attach_current_thread(bool is_daemon);
 508 
 509   // Testers
 510   virtual bool is_Java_thread() const            { return true;  }
 511   virtual bool can_call_java() const             { return true; }
 512 
 513   virtual bool is_active_Java_thread() const {
 514     return on_thread_list() && !is_terminated();
 515   }
 516 
 517   // Thread oop. threadObj() can be NULL for initial JavaThread
 518   // (or for threads attached via JNI)
 519   oop threadObj() const;
 520   void set_threadOopHandles(oop p);
 521   oop vthread() const;
 522   void set_vthread(oop p);
 523   oop extentLocalCache() const;
 524   void set_extentLocalCache(oop p);
 525   oop jvmti_vthread() const;
 526   void set_jvmti_vthread(oop p);
 527 
 528   // Prepare thread and add to priority queue.  If a priority is
 529   // not specified, use the priority of the thread object. Threads_lock
 530   // must be held while this function is called.
 531   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
 532 
 533   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
 534   address saved_exception_pc()                   { return _saved_exception_pc; }
 535 
 536   ThreadFunction entry_point() const             { return _entry_point; }
 537 
 538   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
 539   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
 540 
 541   // Last frame anchor routines
 542 
 543   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
 544 
 545   // last_Java_sp
 546   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
 547   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
 548 
 549   // last_Java_pc
 550 
 551   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
 552 
 553   // Safepoint support
 554   inline JavaThreadState thread_state() const;
 555   inline void set_thread_state(JavaThreadState s);
 556   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
 557   inline ThreadSafepointState* safepoint_state() const;
 558   inline void set_safepoint_state(ThreadSafepointState* state);
 559   inline bool is_at_poll_safepoint();
 560 
 561   // JavaThread termination and lifecycle support:
 562   void smr_delete();
 563   bool on_thread_list() const { return _on_thread_list; }
 564   void set_on_thread_list() { _on_thread_list = true; }
 565 
 566   // thread has called JavaThread::exit(), thread's GC barrier is detached
 567   // or thread is terminated
 568   bool is_exiting() const;
 569   // thread's GC barrier is NOT detached and thread is NOT terminated
 570   bool is_oop_safe() const;
 571   // thread is terminated (no longer on the threads list); the thread must
 572   // be protected by a ThreadsListHandle to avoid potential crashes.
 573   bool check_is_terminated(TerminatedTypes l_terminated) const {
 574     return l_terminated == _thread_terminated || l_terminated == _vm_exited;
 575   }
 576   bool is_terminated() const;
 577   void set_terminated(TerminatedTypes t);
 578 
 579   void block_if_vm_exited();
 580 
 581   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
 582   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
 583 
 584   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
 585   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
 586 
 587   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
 588 
 589   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
 590 
 591   // Continuation support
 592   oop get_continuation() const;
 593   ContinuationEntry* last_continuation() const { return _cont_entry; }
 594   void set_cont_fastpath(intptr_t* x)          { _cont_fastpath = x; }
 595   void push_cont_fastpath(intptr_t* sp)        { if (sp > _cont_fastpath) _cont_fastpath = sp; }
 596   void set_cont_fastpath_thread_state(bool x)  { _cont_fastpath_thread_state = (int)x; }
 597   intptr_t* raw_cont_fastpath() const          { return _cont_fastpath; }
 598   bool cont_fastpath() const                   { return _cont_fastpath == NULL && _cont_fastpath_thread_state != 0; }
 599   bool cont_fastpath_thread_state() const      { return _cont_fastpath_thread_state != 0; }
 600 
 601   void inc_held_monitor_count(int i = 1, bool jni = false);
 602   void dec_held_monitor_count(int i = 1, bool jni = false);
 603 
 604   int64_t held_monitor_count() { return (int64_t)_held_monitor_count; }
 605   int64_t jni_monitor_count()  { return (int64_t)_jni_monitor_count;  }
 606   void clear_jni_monitor_count() { _jni_monitor_count = 0;   }
 607 
 608   inline bool is_vthread_mounted() const;
 609   inline const ContinuationEntry* vthread_continuation() const;
 610 
 611  private:
 612   DEBUG_ONLY(void verify_frame_info();)
 613 
 614   // Support for thread handshake operations
 615   HandshakeState _handshake;
 616  public:
 617   HandshakeState* handshake_state() { return &_handshake; }
 618 
 619   // A JavaThread can always safely operate on it self and other threads
 620   // can do it safely if they are the active handshaker.
 621   bool is_handshake_safe_for(Thread* th) const {
 622     return _handshake.active_handshaker() == th || this == th;
 623   }
 624 
 625   // Suspend/resume support for JavaThread
 626   // higher-level suspension/resume logic called by the public APIs
 627   bool java_suspend();
 628   bool java_resume();
 629   bool is_suspended()     { return _handshake.is_suspended(); }
 630 
 631   // Check for async exception in addition to safepoint.
 632   static void check_special_condition_for_native_trans(JavaThread *thread);
 633 
 634   // Synchronize with another thread that is deoptimizing objects of the
 635   // current thread, i.e. reverts optimizations based on escape analysis.
 636   void wait_for_object_deoptimization();
 637 
 638 #if INCLUDE_JVMTI
 639   inline void set_carrier_thread_suspended();
 640   inline void clear_carrier_thread_suspended();
 641 
 642   bool is_carrier_thread_suspended() const {
 643     return _carrier_thread_suspended;
 644   }
 645 
 646   bool is_in_VTMS_transition() const             { return _is_in_VTMS_transition; }
 647   void set_is_in_VTMS_transition(bool val);
 648 #ifdef ASSERT
 649   bool is_VTMS_transition_disabler() const       { return _is_VTMS_transition_disabler; }
 650   void set_is_VTMS_transition_disabler(bool val);
 651 #endif
 652 #endif
 653 
 654   // Support for object deoptimization and JFR suspension
 655   void handle_special_runtime_exit_condition();
 656   bool has_special_runtime_exit_condition() {
 657     return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
 658   }
 659 
 660   // Fast-locking support
 661   bool is_lock_owned(address adr) const;
 662   bool is_lock_owned_current(address adr) const; // virtual if mounted, otherwise whole thread
 663   bool is_lock_owned_carrier(address adr) const;
 664 
 665   // Accessors for vframe array top
 666   // The linked list of vframe arrays are sorted on sp. This means when we
 667   // unpack the head must contain the vframe array to unpack.
 668   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
 669   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
 670 
 671   // Side structure for deferring update of java frame locals until deopt occurs
 672   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
 673   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
 674 
 675   // These only really exist to make debugging deopt problems simpler
 676 
 677   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
 678   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
 679 
 680   // The special resourceMark used during deoptimization
 681 
 682   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
 683   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
 684 
 685   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
 686   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
 687 
 688   Method*    callee_target() const               { return _callee_target; }
 689   void set_callee_target  (Method* x)          { _callee_target   = x; }
 690 
 691   // Oop results of vm runtime calls
 692   oop  vm_result() const                         { return _vm_result; }
 693   void set_vm_result  (oop x)                    { _vm_result   = x; }
 694 
 695   Metadata*    vm_result_2() const               { return _vm_result_2; }
 696   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
 697 
 698   oop return_buffered_value() const              { return _return_buffered_value; }
 699   void set_return_buffered_value(oop val)        { _return_buffered_value = val; }
 700 
 701   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
 702   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
 703 
 704 #if INCLUDE_JVMCI
 705   int  pending_deoptimization() const             { return _pending_deoptimization; }
 706   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
 707   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
 708   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
 709   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
 710   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
 711   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
 712   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
 713   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
 714 
 715   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
 716   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
 717 
 718   JVMCIRuntime* libjvmci_runtime() const          { return _libjvmci_runtime; }
 719   void set_libjvmci_runtime(JVMCIRuntime* rt) {
 720     assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
 721     _libjvmci_runtime = rt;
 722   }
 723 #endif // INCLUDE_JVMCI
 724 
 725   // Exception handling for compiled methods
 726   oop      exception_oop() const;
 727   address  exception_pc() const                  { return _exception_pc; }
 728   address  exception_handler_pc() const          { return _exception_handler_pc; }
 729   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
 730 
 731   void set_exception_oop(oop o);
 732   void set_exception_pc(address a)               { _exception_pc = a; }
 733   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
 734   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
 735 
 736   void clear_exception_oop_and_pc() {
 737     set_exception_oop(NULL);
 738     set_exception_pc(NULL);
 739   }
 740 
 741   // Check if address is in the usable part of the stack (excludes protected
 742   // guard pages). Can be applied to any thread and is an approximation for
 743   // using is_in_live_stack when the query has to happen from another thread.
 744   bool is_in_usable_stack(address adr) const {
 745     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
 746   }
 747 
 748   // Misc. accessors/mutators
 749   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
 750   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
 751   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
 752 
 753   static ByteSize extentLocalCache_offset()       { return byte_offset_of(JavaThread, _extentLocalCache); }
 754 
 755   // For assembly stub generation
 756   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
 757   static ByteSize vthread_offset()               { return byte_offset_of(JavaThread, _vthread); }
 758   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
 759   static ByteSize pending_jni_exception_check_fn_offset() {
 760     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
 761   }
 762   static ByteSize last_Java_sp_offset() {
 763     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
 764   }
 765   static ByteSize last_Java_pc_offset() {
 766     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
 767   }
 768   static ByteSize frame_anchor_offset() {
 769     return byte_offset_of(JavaThread, _anchor);
 770   }
 771   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
 772   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
 773   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
 774   static ByteSize return_buffered_value_offset() { return byte_offset_of(JavaThread, _return_buffered_value); }
 775   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
 776   static ByteSize polling_word_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_word);}
 777   static ByteSize polling_page_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_page);}
 778   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
 779   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
 780 #if INCLUDE_JVMCI
 781   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
 782   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
 783   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
 784   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
 785   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
 786   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
 787 #endif // INCLUDE_JVMCI
 788   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
 789   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
 790   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
 791   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
 792 
 793   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
 794 
 795   // StackOverflow offsets
 796   static ByteSize stack_overflow_limit_offset()  {
 797     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
 798   }
 799   static ByteSize stack_guard_state_offset()     {
 800     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
 801   }
 802   static ByteSize reserved_stack_activation_offset() {
 803     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
 804   }
 805   static ByteSize shadow_zone_safe_limit()  {
 806     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
 807   }
 808   static ByteSize shadow_zone_growth_watermark()  {
 809     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
 810   }
 811 
 812   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
 813 
 814   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
 815   static ByteSize should_post_on_exceptions_flag_offset() {
 816     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
 817   }
 818   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
 819   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
 820 
 821   static ByteSize cont_entry_offset()         { return byte_offset_of(JavaThread, _cont_entry); }
 822   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
 823   static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
 824 
 825   // Returns the jni environment for this thread
 826   JNIEnv* jni_environment()                      { return &_jni_environment; }
 827 
 828   // Returns the current thread as indicated by the given JNIEnv.
 829   // We don't assert it is Thread::current here as that is done at the
 830   // external JNI entry points where the JNIEnv is passed into the VM.
 831   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
 832     JavaThread* current = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
 833     // We can't normally get here in a thread that has completed its
 834     // execution and so "is_terminated", except when the call is from
 835     // AsyncGetCallTrace, which can be triggered by a signal at any point in
 836     // a thread's lifecycle. A thread is also considered terminated if the VM
 837     // has exited, so we have to check this and block in case this is a daemon
 838     // thread returning to the VM (the JNI DirectBuffer entry points rely on
 839     // this).
 840     if (current->is_terminated()) {
 841       current->block_if_vm_exited();
 842     }
 843     return current;
 844   }
 845 
 846   // JNI critical regions. These can nest.
 847   bool in_critical()    { return _jni_active_critical > 0; }
 848   bool in_last_critical()  { return _jni_active_critical == 1; }
 849   inline void enter_critical();
 850   void exit_critical() {
 851     assert(Thread::current() == this, "this must be current thread");
 852     _jni_active_critical--;
 853     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
 854   }
 855 
 856   // Checked JNI: is the programmer required to check for exceptions, if so specify
 857   // which function name. Returning to a Java frame should implicitly clear the
 858   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
 859   // VM->Java transitions are not cleared, it is expected that JNI code enclosed
 860   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
 861   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
 862   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
 863   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
 864   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
 865 
 866   // For deadlock detection
 867   int depth_first_number() { return _depth_first_number; }
 868   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
 869 
 870  private:
 871   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
 872 
 873  public:
 874   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
 875   void add_monitor_chunk(MonitorChunk* chunk);
 876   void remove_monitor_chunk(MonitorChunk* chunk);
 877   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
 878   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
 879   void dec_in_deopt_handler() {
 880     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
 881     if (_in_deopt_handler > 0) { // robustness
 882       _in_deopt_handler--;
 883     }
 884   }
 885 
 886  private:
 887   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
 888 
 889   // factor out low-level mechanics for use in both normal and error cases
 890   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
 891 
 892  public:
 893 
 894   // Frame iteration; calls the function f for all frames on the stack
 895   void frames_do(void f(frame*, const RegisterMap*));
 896 
 897   // Memory operations
 898   void oops_do_frames(OopClosure* f, CodeBlobClosure* cf);
 899   void oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf);
 900 
 901   // GC operations
 902   virtual void nmethods_do(CodeBlobClosure* cf);
 903 
 904   // RedefineClasses Support
 905   void metadata_do(MetadataClosure* f);
 906 
 907   // Debug method asserting thread states are correct during a handshake operation.
 908   DEBUG_ONLY(void verify_states_for_handshake();)
 909 
 910   // Misc. operations
 911   const char* name() const;
 912   const char* type_name() const { return "JavaThread"; }
 913   static const char* name_for(oop thread_obj);
 914 
 915   void print_on(outputStream* st, bool print_extended_info) const;
 916   void print_on(outputStream* st) const { print_on(st, false); }
 917   void print() const;
 918   void print_thread_state_on(outputStream*) const;
 919   const char* thread_state_name() const;
 920   void print_on_error(outputStream* st, char* buf, int buflen) const;
 921   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
 922   void verify();
 923 
 924   // Accessing frames
 925   frame last_frame() {
 926     _anchor.make_walkable();
 927     return pd_last_frame();
 928   }
 929   javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
 930 
 931   frame carrier_last_frame(RegisterMap* reg_map);
 932   javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
 933 
 934   frame vthread_last_frame();
 935   javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
 936 
 937   frame platform_thread_last_frame(RegisterMap* reg_map);
 938   javaVFrame*  platform_thread_last_java_vframe(RegisterMap* reg_map) {
 939     return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
 940   }
 941 
 942   javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
 943 
 944   // Returns method at 'depth' java or native frames down the stack
 945   // Used for security checks
 946   Klass* security_get_caller_class(int depth);
 947 
 948   // Print stack trace in external format
 949   void print_stack_on(outputStream* st);
 950   void print_stack() { print_stack_on(tty); }
 951 
 952   // Print stack traces in various internal formats
 953   void trace_stack()                             PRODUCT_RETURN;
 954   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
 955   void trace_frames()                            PRODUCT_RETURN;
 956 
 957   // Print an annotated view of the stack frames
 958   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
 959   void validate_frame_layout() {
 960     print_frame_layout(0, true);
 961   }
 962 
 963   // Function for testing deoptimization
 964   void deoptimize();
 965   void make_zombies();
 966 
 967   void deoptimize_marked_methods();
 968 
 969  public:
 970   // Returns the running thread as a JavaThread
 971   static JavaThread* current() {
 972     return JavaThread::cast(Thread::current());
 973   }
 974 
 975   // Returns the current thread as a JavaThread, or NULL if not attached
 976   static inline JavaThread* current_or_null();
 977 
 978   // Casts
 979   static JavaThread* cast(Thread* t) {
 980     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
 981     return static_cast<JavaThread*>(t);
 982   }
 983 
 984   static const JavaThread* cast(const Thread* t) {
 985     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
 986     return static_cast<const JavaThread*>(t);
 987   }
 988 
 989   // Returns the active Java thread.  Do not use this if you know you are calling
 990   // from a JavaThread, as it's slower than JavaThread::current.  If called from
 991   // the VMThread, it also returns the JavaThread that instigated the VMThread's
 992   // operation.  You may not want that either.
 993   static JavaThread* active();
 994 
 995  protected:
 996   virtual void pre_run();
 997   virtual void run();
 998   void thread_main_inner();
 999   virtual void post_run();
1000 
1001  public:
1002   // Thread local information maintained by JVMTI.
1003   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1004   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1005   // getter is used to get this JavaThread's JvmtiThreadState if it has
1006   // one which means NULL can be returned. JvmtiThreadState::state_for()
1007   // is used to get the specified JavaThread's JvmtiThreadState if it has
1008   // one or it allocates a new JvmtiThreadState for the JavaThread and
1009   // returns it. JvmtiThreadState::state_for() will return NULL only if
1010   // the specified JavaThread is exiting.
1011   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1012   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1013 
1014 #if INCLUDE_JVMTI
1015   // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1016   JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1017 #endif
1018 
1019   // JVMTI PopFrame support
1020   // Setting and clearing popframe_condition
1021   // All of these enumerated values are bits. popframe_pending
1022   // indicates that a PopFrame() has been requested and not yet been
1023   // completed. popframe_processing indicates that that PopFrame() is in
1024   // the process of being completed. popframe_force_deopt_reexecution_bit
1025   // indicates that special handling is required when returning to a
1026   // deoptimized caller.
1027   enum PopCondition {
1028     popframe_inactive                      = 0x00,
1029     popframe_pending_bit                   = 0x01,
1030     popframe_processing_bit                = 0x02,
1031     popframe_force_deopt_reexecution_bit   = 0x04
1032   };
1033   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1034   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1035   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1036   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1037   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1038   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1039   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1040   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1041 
1042   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1043   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1044   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1045 
1046   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1047   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1048   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1049 
1050  private:
1051   // Saved incoming arguments to popped frame.
1052   // Used only when popped interpreted frame returns to deoptimized frame.
1053   void*    _popframe_preserved_args;
1054   int      _popframe_preserved_args_size;
1055 
1056  public:
1057   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1058   void* popframe_preserved_args();
1059   ByteSize popframe_preserved_args_size();
1060   WordSize popframe_preserved_args_size_in_words();
1061   void  popframe_free_preserved_args();
1062 
1063 
1064  private:
1065   JvmtiThreadState *_jvmti_thread_state;
1066 
1067   // Used by the interpreter in fullspeed mode for frame pop, method
1068   // entry, method exit and single stepping support. This field is
1069   // only set to non-zero at a safepoint or using a direct handshake
1070   // (see EnterInterpOnlyModeClosure).
1071   // It can be set to zero asynchronously to this threads execution (i.e., without
1072   // safepoint/handshake or a lock) so we have to be very careful.
1073   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1074   int               _interp_only_mode;
1075 
1076  public:
1077   // used by the interpreter for fullspeed debugging support (see above)
1078   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1079   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1080   int get_interp_only_mode()                { return _interp_only_mode; }
1081   int set_interp_only_mode(int val)         { return _interp_only_mode = val; }
1082   void increment_interp_only_mode()         { ++_interp_only_mode; }
1083   void decrement_interp_only_mode()         { --_interp_only_mode; }
1084 
1085   // support for cached flag that indicates whether exceptions need to be posted for this thread
1086   // if this is false, we can avoid deoptimizing when events are thrown
1087   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1088  private:
1089   int    _should_post_on_exceptions_flag;
1090 
1091  public:
1092   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1093   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1094 
1095  private:
1096   ThreadStatistics *_thread_stat;
1097 
1098  public:
1099   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1100 
1101   // Return a blocker object for which this thread is blocked parking.
1102   oop current_park_blocker();
1103 
1104  private:
1105   static size_t _stack_size_at_create;
1106 
1107  public:
1108   static inline size_t stack_size_at_create(void) {
1109     return _stack_size_at_create;
1110   }
1111   static inline void set_stack_size_at_create(size_t value) {
1112     _stack_size_at_create = value;
1113   }
1114 
1115   // Machine dependent stuff
1116 #include OS_CPU_HEADER(javaThread)
1117 
1118   // JSR166 per-thread parker
1119  private:
1120   Parker _parker;
1121  public:
1122   Parker* parker() { return &_parker; }
1123 
1124  public:
1125   // clearing/querying jni attach status
1126   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1127   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1128   inline void set_done_attaching_via_jni();
1129 
1130   // Stack dump assistance:
1131   // Track the class we want to initialize but for which we have to wait
1132   // on its init_lock() because it is already being initialized.
1133   void set_class_to_be_initialized(InstanceKlass* k);
1134   InstanceKlass* class_to_be_initialized() const;
1135 
1136 private:
1137   InstanceKlass* _class_to_be_initialized;
1138 
1139   // java.lang.Thread.sleep support
1140   ParkEvent * _SleepEvent;
1141 public:
1142   bool sleep(jlong millis);
1143 
1144   // java.lang.Thread interruption support
1145   void interrupt();
1146   bool is_interrupted(bool clear_interrupted);
1147 
1148   static OopStorage* thread_oop_storage();
1149 
1150   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1151 
1152   // Helper function to create the java.lang.Thread object for a
1153   // VM-internal thread. The thread will have the given name, be
1154   // part of the System ThreadGroup and if is_visible is true will be
1155   // discoverable via the system ThreadGroup.
1156   static Handle create_system_thread_object(const char* name, bool is_visible, TRAPS);
1157 
1158   // Helper function to start a VM-internal daemon thread.
1159   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1160   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1161                                     Handle thread_oop, ThreadPriority prio);
1162 
1163   // Helper function to do vm_exit_on_initialization for osthread
1164   // resource allocation failure.
1165   static void vm_exit_on_osthread_failure(JavaThread* thread);
1166 
1167   // AsyncGetCallTrace support
1168   inline bool in_asgct(void) {return _in_asgct;}
1169   inline void set_in_asgct(bool value) {_in_asgct = value;}
1170 };
1171 
1172 inline JavaThread* JavaThread::current_or_null() {
1173   Thread* current = Thread::current_or_null();
1174   return current != nullptr ? JavaThread::cast(current) : nullptr;
1175 }
1176 
1177 class UnlockFlagSaver {
1178   private:
1179     JavaThread* _thread;
1180     bool _do_not_unlock;
1181   public:
1182     UnlockFlagSaver(JavaThread* t) {
1183       _thread = t;
1184       _do_not_unlock = t->do_not_unlock_if_synchronized();
1185       t->set_do_not_unlock_if_synchronized(false);
1186     }
1187     ~UnlockFlagSaver() {
1188       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1189     }
1190 };
1191 
1192 class JNIHandleMark : public StackObj {
1193   JavaThread* _thread;
1194  public:
1195   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1196     thread->push_jni_handle_block();
1197   }
1198   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1199 };
1200 
1201 #endif // SHARE_RUNTIME_JAVATHREAD_HPP