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_THREAD_HPP
  27 #define SHARE_RUNTIME_THREAD_HPP
  28 
  29 #include "jni.h"
  30 #include "gc/shared/gcThreadLocalData.hpp"
  31 #include "gc/shared/threadLocalAllocBuffer.hpp"
  32 #include "memory/allocation.hpp"
  33 #include "oops/oop.hpp"
  34 #include "oops/oopHandle.hpp"
  35 #include "runtime/frame.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/handshake.hpp"
  38 #include "runtime/javaFrameAnchor.hpp"
  39 #include "runtime/mutexLocker.hpp"
  40 #include "runtime/os.hpp"
  41 #include "runtime/park.hpp"
  42 #include "runtime/safepointMechanism.hpp"
  43 #include "runtime/stackWatermarkSet.hpp"
  44 #include "runtime/stackOverflow.hpp"
  45 #include "runtime/threadHeapSampler.hpp"
  46 #include "runtime/threadLocalStorage.hpp"
  47 #include "runtime/threadStatisticalInfo.hpp"
  48 #include "runtime/unhandledOops.hpp"
  49 #include "utilities/align.hpp"
  50 #include "utilities/exceptions.hpp"
  51 #include "utilities/globalDefinitions.hpp"
  52 #include "utilities/macros.hpp"
  53 #if INCLUDE_JFR
  54 #include "jfr/support/jfrThreadExtension.hpp"
  55 #endif
  56 
  57 class SafeThreadsListPtr;
  58 class ThreadSafepointState;
  59 class ThreadsList;
  60 class ThreadsSMRSupport;
  61 
  62 class JNIHandleBlock;
  63 class JvmtiRawMonitor;
  64 class JvmtiSampledObjectAllocEventCollector;
  65 class JvmtiThreadState;
  66 class JvmtiVMObjectAllocEventCollector;
  67 class OSThread;
  68 class ThreadStatistics;
  69 class ConcurrentLocksDump;
  70 class MonitorInfo;
  71 
  72 class vframeArray;
  73 class vframe;
  74 class javaVFrame;
  75 
  76 class DeoptResourceMark;
  77 class JvmtiDeferredUpdates;
  78 
  79 class ThreadClosure;
  80 class ICRefillVerifier;
  81 
  82 class Metadata;
  83 class ResourceArea;
  84 
  85 class OopStorage;
  86 
  87 DEBUG_ONLY(class ResourceMark;)
  88 
  89 class WorkerThread;
  90 
  91 class JavaThread;
  92 
  93 // Class hierarchy
  94 // - Thread
  95 //   - JavaThread
  96 //     - various subclasses eg CompilerThread, ServiceThread
  97 //   - NonJavaThread
  98 //     - NamedThread
  99 //       - VMThread
 100 //       - ConcurrentGCThread
 101 //       - WorkerThread
 102 //     - WatcherThread
 103 //     - JfrThreadSampler
 104 //     - LogAsyncWriter
 105 //
 106 // All Thread subclasses must be either JavaThread or NonJavaThread.
 107 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 108 // a partially constructed/destroyed Thread.
 109 
 110 // Thread execution sequence and actions:
 111 // All threads:
 112 //  - thread_native_entry  // per-OS native entry point
 113 //    - stack initialization
 114 //    - other OS-level initialization (signal masks etc)
 115 //    - handshake with creating thread (if not started suspended)
 116 //    - this->call_run()  // common shared entry point
 117 //      - shared common initialization
 118 //      - this->pre_run()  // virtual per-thread-type initialization
 119 //      - this->run()      // virtual per-thread-type "main" logic
 120 //      - shared common tear-down
 121 //      - this->post_run()  // virtual per-thread-type tear-down
 122 //      - // 'this' no longer referenceable
 123 //    - OS-level tear-down (minimal)
 124 //    - final logging
 125 //
 126 // For JavaThread:
 127 //   - this->run()  // virtual but not normally overridden
 128 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 129 //       - this->entry_point()  // set differently for each kind of JavaThread
 130 
 131 class Thread: public ThreadShadow {
 132   friend class VMStructs;
 133   friend class JVMCIVMStructs;
 134  private:
 135 
 136 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 137   // Current thread is maintained as a thread-local variable
 138   static THREAD_LOCAL Thread* _thr_current;
 139 #endif
 140 
 141   // Thread local data area available to the GC. The internal
 142   // structure and contents of this data area is GC-specific.
 143   // Only GC and GC barrier code should access this data area.
 144   GCThreadLocalData _gc_data;
 145 
 146  public:
 147   static ByteSize gc_data_offset() {
 148     return byte_offset_of(Thread, _gc_data);
 149   }
 150 
 151   template <typename T> T* gc_data() {
 152     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 153     return reinterpret_cast<T*>(&_gc_data);
 154   }
 155 
 156   // Exception handling
 157   // (Note: _pending_exception and friends are in ThreadShadow)
 158   //oop       _pending_exception;                // pending exception for current thread
 159   // const char* _exception_file;                   // file information for exception (debugging only)
 160   // int         _exception_line;                   // line information for exception (debugging only)
 161  protected:
 162 
 163   DEBUG_ONLY(static Thread* _starting_thread;)
 164 
 165   // JavaThread lifecycle support:
 166   friend class SafeThreadsListPtr;  // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
 167   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 168   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 169   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 170   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 171   friend class ThreadsListHandleTest;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 172   friend class ValidateHazardPtrsClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 173 
 174   ThreadsList* volatile _threads_hazard_ptr;
 175   SafeThreadsListPtr*   _threads_list_ptr;
 176   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 177   ThreadsList*          get_threads_hazard_ptr() const;
 178   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 179   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 180     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 181   }
 182   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 183     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 184   }
 185   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 186     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 187   }
 188   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 189   uint _nested_threads_hazard_ptr_cnt;
 190   void dec_nested_threads_hazard_ptr_cnt() {
 191     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 192     _nested_threads_hazard_ptr_cnt--;
 193   }
 194   void inc_nested_threads_hazard_ptr_cnt() {
 195     _nested_threads_hazard_ptr_cnt++;
 196   }
 197   uint nested_threads_hazard_ptr_cnt() {
 198     return _nested_threads_hazard_ptr_cnt;
 199   }
 200 
 201  public:
 202   // Is the target JavaThread protected by the calling Thread or by some other
 203   // mechanism?
 204   static bool is_JavaThread_protected(const JavaThread* target);
 205   // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
 206   // with the calling Thread?
 207   static bool is_JavaThread_protected_by_TLH(const JavaThread* target);
 208 
 209   void* operator new(size_t size) throw() { return allocate(size, true); }
 210   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 211     return allocate(size, false); }
 212   void  operator delete(void* p);
 213 
 214  protected:
 215   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 216 
 217  private:
 218   DEBUG_ONLY(bool _suspendible_thread;)
 219 
 220  public:
 221   // Determines if a heap allocation failure will be retried
 222   // (e.g., by deoptimizing and re-executing in the interpreter).
 223   // In this case, the failed allocation must raise
 224   // Universe::out_of_memory_error_retry() and omit side effects
 225   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 226   // and -XX:OnOutOfMemoryError.
 227   virtual bool in_retryable_allocation() const { return false; }
 228 
 229 #ifdef ASSERT
 230   void set_suspendible_thread() {
 231     _suspendible_thread = true;
 232   }
 233 
 234   void clear_suspendible_thread() {
 235     _suspendible_thread = false;
 236   }
 237 
 238   bool is_suspendible_thread() { return _suspendible_thread; }
 239 #endif
 240 
 241  private:
 242   // Point to the last handle mark
 243   HandleMark* _last_handle_mark;
 244 
 245   // Claim value for parallel iteration over threads.
 246   uintx _threads_do_token;
 247 
 248   // Support for GlobalCounter
 249  private:
 250   volatile uintx _rcu_counter;
 251  public:
 252   volatile uintx* get_rcu_counter() {
 253     return &_rcu_counter;
 254   }
 255 
 256  public:
 257   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 258   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 259  private:
 260 
 261 #ifdef ASSERT
 262   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 263 
 264  public:
 265   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 266     return _missed_ic_stub_refill_verifier;
 267   }
 268 
 269   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 270     _missed_ic_stub_refill_verifier = verifier;
 271   }
 272 #endif // ASSERT
 273 
 274  private:
 275   // Used by SkipGCALot class.
 276   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 277 
 278   friend class GCLocker;
 279 
 280  private:
 281   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 282   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 283                                                 // the Java heap
 284   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 285 
 286   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 287 
 288   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 289 
 290   JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread
 291                                                  // is waiting to lock
 292  public:
 293   // Constructor
 294   Thread();
 295   virtual ~Thread() = 0;        // Thread is abstract.
 296 
 297   // Manage Thread::current()
 298   void initialize_thread_current();
 299   static void clear_thread_current(); // TLS cleanup needed before threads terminate
 300 
 301  protected:
 302   // To be implemented by children.
 303   virtual void run() = 0;
 304   virtual void pre_run() = 0;
 305   virtual void post_run() = 0;  // Note: Thread must not be deleted prior to calling this!
 306 
 307 #ifdef ASSERT
 308   enum RunState {
 309     PRE_CALL_RUN,
 310     CALL_RUN,
 311     PRE_RUN,
 312     RUN,
 313     POST_RUN
 314     // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
 315   };
 316   RunState _run_state;  // for lifecycle checks
 317 #endif
 318 
 319 
 320  public:
 321   // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
 322   void call_run();
 323 
 324   // Testers
 325   virtual bool is_VM_thread()       const            { return false; }
 326   virtual bool is_Java_thread()     const            { return false; }
 327   virtual bool is_Compiler_thread() const            { return false; }
 328   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 329   virtual bool is_service_thread() const             { return false; }
 330   virtual bool is_monitor_deflation_thread() const   { return false; }
 331   virtual bool is_hidden_from_external_view() const  { return false; }
 332   virtual bool is_jvmti_agent_thread() const         { return false; }
 333   virtual bool is_Watcher_thread() const             { return false; }
 334   virtual bool is_ConcurrentGC_thread() const        { return false; }
 335   virtual bool is_Named_thread() const               { return false; }
 336   virtual bool is_Worker_thread() const              { return false; }
 337   virtual bool is_JfrSampler_thread() const          { return false; }
 338 
 339   // Can this thread make Java upcalls
 340   virtual bool can_call_java() const                 { return false; }
 341 
 342   // Is this a JavaThread that is on the VM's current ThreadsList?
 343   // If so it must participate in the safepoint protocol.
 344   virtual bool is_active_Java_thread() const         { return false; }
 345 
 346   // All threads are given names. For singleton subclasses we can
 347   // just hard-wire the known name of the instance. JavaThreads and
 348   // NamedThreads support multiple named instances, and dynamic
 349   // changing of the name of an instance.
 350   virtual const char* name() const { return "Unknown thread"; }
 351 
 352   // A thread's type name is also made available for debugging
 353   // and logging.
 354   virtual const char* type_name() const { return "Thread"; }
 355 
 356   // Returns the current thread (ASSERTS if NULL)
 357   static inline Thread* current();
 358   // Returns the current thread, or NULL if not attached
 359   static inline Thread* current_or_null();
 360   // Returns the current thread, or NULL if not attached, and is
 361   // safe for use from signal-handlers
 362   static inline Thread* current_or_null_safe();
 363 
 364   // Common thread operations
 365 #ifdef ASSERT
 366   static void check_for_dangling_thread_pointer(Thread *thread);
 367 #endif
 368   static void set_priority(Thread* thread, ThreadPriority priority);
 369   static ThreadPriority get_priority(const Thread* const thread);
 370   static void start(Thread* thread);
 371 
 372   void set_native_thread_name(const char *name) {
 373     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 374     os::set_native_thread_name(name);
 375   }
 376 
 377   // Support for Unhandled Oop detection
 378   // Add the field for both, fastdebug and debug, builds to keep
 379   // Thread's fields layout the same.
 380   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 381 #ifdef CHECK_UNHANDLED_OOPS
 382  private:
 383   UnhandledOops* _unhandled_oops;
 384 #elif defined(ASSERT)
 385  private:
 386   void* _unhandled_oops;
 387 #endif
 388 #ifdef CHECK_UNHANDLED_OOPS
 389  public:
 390   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 391   // Mark oop safe for gc.  It may be stack allocated but won't move.
 392   void allow_unhandled_oop(oop *op) {
 393     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 394   }
 395   // Clear oops at safepoint so crashes point to unhandled oop violator
 396   void clear_unhandled_oops() {
 397     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 398   }
 399 #endif // CHECK_UNHANDLED_OOPS
 400 
 401  public:
 402 #ifndef PRODUCT
 403   bool skip_gcalot()           { return _skip_gcalot; }
 404   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 405 #endif
 406 
 407   // Resource area
 408   ResourceArea* resource_area() const            { return _resource_area; }
 409   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 410 
 411   OSThread* osthread() const                     { return _osthread;   }
 412   void set_osthread(OSThread* thread)            { _osthread = thread; }
 413 
 414   // Internal handle support
 415   HandleArea* handle_area() const                { return _handle_area; }
 416   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 417 
 418   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 419   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 420 
 421   // Thread-Local Allocation Buffer (TLAB) support
 422   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 423   void initialize_tlab();
 424 
 425   jlong allocated_bytes()               { return _allocated_bytes; }
 426   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 427   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 428   inline jlong cooked_allocated_bytes();
 429 
 430   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 431 
 432   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 433 
 434   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 435 
 436   // For tracking the Jvmti raw monitor the thread is pending on.
 437   JvmtiRawMonitor* current_pending_raw_monitor() {
 438     return _current_pending_raw_monitor;
 439   }
 440   void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) {
 441     _current_pending_raw_monitor = monitor;
 442   }
 443 
 444   // GC support
 445   // Apply "f->do_oop" to all root oops in "this".
 446   //   Used by JavaThread::oops_do.
 447   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 448   virtual void oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf);
 449   virtual void oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {}
 450   void oops_do(OopClosure* f, CodeBlobClosure* cf);
 451 
 452   // Handles the parallel case for claim_threads_do.
 453  private:
 454   bool claim_par_threads_do(uintx claim_token);
 455  public:
 456   // Requires that "claim_token" is that of the current iteration.
 457   // If "is_par" is false, sets the token of "this" to
 458   // "claim_token", and returns "true".  If "is_par" is true,
 459   // uses an atomic instruction to set the current thread's token to
 460   // "claim_token", if it is not already.  Returns "true" iff the
 461   // calling thread does the update, this indicates that the calling thread
 462   // has claimed the thread in the current iteration.
 463   bool claim_threads_do(bool is_par, uintx claim_token) {
 464     if (!is_par) {
 465       _threads_do_token = claim_token;
 466       return true;
 467     } else {
 468       return claim_par_threads_do(claim_token);
 469     }
 470   }
 471 
 472   uintx threads_do_token() const { return _threads_do_token; }
 473 
 474   // jvmtiRedefineClasses support
 475   void metadata_handles_do(void f(Metadata*));
 476 
 477  private:
 478   // Check if address is within the given range of this thread's
 479   // stack:  stack_base() > adr >/>= limit
 480   // The check is inclusive of limit if passed true, else exclusive.
 481   bool is_in_stack_range(address adr, address limit, bool inclusive) const {
 482     assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack");
 483     return stack_base() > adr && (inclusive ? adr >= limit : adr > limit);
 484   }
 485 
 486  public:
 487   // Used by fast lock support
 488   virtual bool is_lock_owned(address adr) const;
 489 
 490   // Check if address is within the given range of this thread's
 491   // stack:  stack_base() > adr >= limit
 492   bool is_in_stack_range_incl(address adr, address limit) const {
 493     return is_in_stack_range(adr, limit, true);
 494   }
 495 
 496   // Check if address is within the given range of this thread's
 497   // stack:  stack_base() > adr > limit
 498   bool is_in_stack_range_excl(address adr, address limit) const {
 499     return is_in_stack_range(adr, limit, false);
 500   }
 501 
 502   // Check if address is in the stack mapped to this thread. Used mainly in
 503   // error reporting (so has to include guard zone) and frame printing.
 504   // Expects _stack_base to be initialized - checked with assert.
 505   bool is_in_full_stack_checked(address adr) const {
 506     return is_in_stack_range_incl(adr, stack_end());
 507   }
 508 
 509   // Like is_in_full_stack_checked but without the assertions as this
 510   // may be called in a thread before _stack_base is initialized.
 511   bool is_in_full_stack(address adr) const {
 512     address stack_end = _stack_base - _stack_size;
 513     return _stack_base > adr && adr >= stack_end;
 514   }
 515 
 516   // Check if address is in the live stack of this thread (not just for locks).
 517   // Warning: can only be called by the current thread on itself.
 518   bool is_in_live_stack(address adr) const {
 519     assert(Thread::current() == this, "is_in_live_stack can only be called from current thread");
 520     return is_in_stack_range_incl(adr, os::current_stack_pointer());
 521   }
 522 
 523   // Sets this thread as starting thread. Returns failure if thread
 524   // creation fails due to lack of memory, too many threads etc.
 525   bool set_as_starting_thread();
 526 
 527 protected:
 528   // OS data associated with the thread
 529   OSThread* _osthread;  // Platform-specific thread information
 530 
 531   // Thread local resource area for temporary allocation within the VM
 532   ResourceArea* _resource_area;
 533 
 534   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 535 
 536   // Thread local handle area for allocation of handles within the VM
 537   HandleArea* _handle_area;
 538   GrowableArray<Metadata*>* _metadata_handles;
 539 
 540   // Support for stack overflow handling, get_thread, etc.
 541   address          _stack_base;
 542   size_t           _stack_size;
 543   int              _lgrp_id;
 544 
 545  public:
 546   // Stack overflow support
 547   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 548   void    set_stack_base(address base) { _stack_base = base; }
 549   size_t  stack_size() const           { return _stack_size; }
 550   void    set_stack_size(size_t size)  { _stack_size = size; }
 551   address stack_end()  const           { return stack_base() - stack_size(); }
 552   void    record_stack_base_and_size();
 553   void    register_thread_stack_with_NMT();
 554   void    unregister_thread_stack_with_NMT();
 555 
 556   int     lgrp_id() const        { return _lgrp_id; }
 557   void    set_lgrp_id(int value) { _lgrp_id = value; }
 558 
 559   // Printing
 560   void print_on(outputStream* st, bool print_extended_info) const;
 561   virtual void print_on(outputStream* st) const { print_on(st, false); }
 562   void print() const;
 563   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 564   // Basic, non-virtual, printing support that is simple and always safe.
 565   void print_value_on(outputStream* st) const;
 566 
 567   // Debug-only code
 568 #ifdef ASSERT
 569  private:
 570   // Deadlock detection support for Mutex locks. List of locks own by thread.
 571   Mutex* _owned_locks;
 572   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 573   // thus the friendship
 574   friend class Mutex;
 575   friend class Monitor;
 576 
 577  public:
 578   void print_owned_locks_on(outputStream* st) const;
 579   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 580   Mutex* owned_locks() const                     { return _owned_locks;          }
 581   bool owns_locks() const                        { return owned_locks() != NULL; }
 582 
 583   // Deadlock detection
 584   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 585   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 586 #endif // ASSERT
 587 
 588  private:
 589   volatile int _jvmti_env_iteration_count;
 590 
 591  public:
 592   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 593   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 594   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 595 
 596   // Code generation
 597   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 598   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 599 
 600   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 601   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 602 
 603   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 604   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 605   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 606   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 607 
 608   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 609 
 610   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 611 
 612  public:
 613   ParkEvent * volatile _ParkEvent;            // for Object monitors, JVMTI raw monitors,
 614                                               // and ObjectSynchronizer::read_stable_mark
 615 
 616   // Termination indicator used by the signal handler.
 617   // _ParkEvent is just a convenient field we can NULL out after setting the JavaThread termination state
 618   // (which can't itself be read from the signal handler if a signal hits during the Thread destructor).
 619   bool has_terminated()                       { return Atomic::load(&_ParkEvent) == NULL; };
 620 
 621   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 622   jint _hashStateX;                           // thread-specific hashCode generator state
 623   jint _hashStateY;
 624   jint _hashStateZ;
 625 
 626   // Low-level leaf-lock primitives used to implement synchronization.
 627   // Not for general synchronization use.
 628   static void SpinAcquire(volatile int * Lock, const char * Name);
 629   static void SpinRelease(volatile int * Lock);
 630 
 631 #if defined(__APPLE__) && defined(AARCH64)
 632  private:
 633   DEBUG_ONLY(bool _wx_init);
 634   WXMode _wx_state;
 635  public:
 636   void init_wx();
 637   WXMode enable_wx(WXMode new_state);
 638 
 639   void assert_wx_state(WXMode expected) {
 640     assert(_wx_state == expected, "wrong state");
 641   }
 642 #endif // __APPLE__ && AARCH64
 643 };
 644 
 645 // Inline implementation of Thread::current()
 646 inline Thread* Thread::current() {
 647   Thread* current = current_or_null();
 648   assert(current != NULL, "Thread::current() called on detached thread");
 649   return current;
 650 }
 651 
 652 inline Thread* Thread::current_or_null() {
 653 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 654   return _thr_current;
 655 #else
 656   if (ThreadLocalStorage::is_initialized()) {
 657     return ThreadLocalStorage::thread();
 658   }
 659   return NULL;
 660 #endif
 661 }
 662 
 663 inline Thread* Thread::current_or_null_safe() {
 664   if (ThreadLocalStorage::is_initialized()) {
 665     return ThreadLocalStorage::thread();
 666   }
 667   return NULL;
 668 }
 669 
 670 class CompilerThread;
 671 
 672 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 673 
 674 class JavaThread: public Thread {
 675   friend class VMStructs;
 676   friend class JVMCIVMStructs;
 677   friend class WhiteBox;
 678   friend class VTBuffer;
 679   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
 680   friend class HandshakeState;
 681  private:
 682   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 683   OopHandle      _threadObj;                     // The Java level thread object
 684 
 685 #ifdef ASSERT
 686  private:
 687   int _java_call_counter;
 688 
 689  public:
 690   int  java_call_counter()                       { return _java_call_counter; }
 691   void inc_java_call_counter()                   { _java_call_counter++; }
 692   void dec_java_call_counter() {
 693     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 694     _java_call_counter--;
 695   }
 696  private:  // restore original namespace restriction
 697 #endif  // ifdef ASSERT
 698 
 699   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 700 
 701   ThreadFunction _entry_point;
 702 
 703   JNIEnv        _jni_environment;
 704 
 705   // Deopt support
 706   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 707 
 708   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 709   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 710   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 711   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
 712   // will be carried out as soon as possible which, in most cases, is just before deoptimization of
 713   // the frame, when control returns to it.
 714   JvmtiDeferredUpdates* _jvmti_deferred_updates;
 715 
 716   // Handshake value for fixing 6243940. We need a place for the i2c
 717   // adapter to store the callee Method*. This value is NEVER live
 718   // across a gc point so it does NOT have to be gc'd
 719   // The handshake is open ended since we can't be certain that it will
 720   // be NULLed. This is because we rarely ever see the race and end up
 721   // in handle_wrong_method which is the backend of the handshake. See
 722   // code in i2c adapters and handle_wrong_method.
 723 
 724   Method*       _callee_target;
 725 
 726   // Used to pass back results to the interpreter or generated code running Java code.
 727   oop           _vm_result;    // oop result is GC-preserved
 728   Metadata*     _vm_result_2;  // non-oop result
 729   oop           _return_buffered_value; // buffered value being returned
 730 
 731   // See ReduceInitialCardMarks: this holds the precise space interval of
 732   // the most recent slow path allocation for which compiled code has
 733   // elided card-marks for performance along the fast-path.
 734   MemRegion     _deferred_card_mark;
 735 
 736   ObjectMonitor* volatile _current_pending_monitor;     // ObjectMonitor this thread is waiting to lock
 737   bool           _current_pending_monitor_is_from_java; // locking is from Java code
 738   ObjectMonitor* volatile _current_waiting_monitor;     // ObjectMonitor on which this thread called Object.wait()
 739 
 740   // Active_handles points to a block of handles
 741   JNIHandleBlock* _active_handles;
 742 
 743   // One-element thread local free list
 744   JNIHandleBlock* _free_handle_block;
 745 
 746  public:
 747   volatile intptr_t _Stalled;
 748 
 749   // For tracking the heavyweight monitor the thread is pending on.
 750   ObjectMonitor* current_pending_monitor() {
 751     // Use Atomic::load() to prevent data race between concurrent modification and
 752     // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
 753     // Especially, reloading pointer from thread after NULL check must be prevented.
 754     return Atomic::load(&_current_pending_monitor);
 755   }
 756   void set_current_pending_monitor(ObjectMonitor* monitor) {
 757     Atomic::store(&_current_pending_monitor, monitor);
 758   }
 759   void set_current_pending_monitor_is_from_java(bool from_java) {
 760     _current_pending_monitor_is_from_java = from_java;
 761   }
 762   bool current_pending_monitor_is_from_java() {
 763     return _current_pending_monitor_is_from_java;
 764   }
 765   ObjectMonitor* current_waiting_monitor() {
 766     // See the comment in current_pending_monitor() above.
 767     return Atomic::load(&_current_waiting_monitor);
 768   }
 769   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 770     Atomic::store(&_current_waiting_monitor, monitor);
 771   }
 772 
 773   // JNI handle support
 774   JNIHandleBlock* active_handles() const         { return _active_handles; }
 775   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 776   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 777   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 778 
 779   void push_jni_handle_block();
 780   void pop_jni_handle_block();
 781 
 782  private:
 783   MonitorChunk* _monitor_chunks;              // Contains the off stack monitors
 784                                               // allocated during deoptimization
 785                                               // and by JNI_MonitorEnter/Exit
 786 
 787   enum SuspendFlags {
 788     // NOTE: avoid using the sign-bit as cc generates different test code
 789     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 790     _has_async_exception     = 0x00000001U, // there is a pending async exception
 791     _async_delivery_disabled = 0x00000002U, // async exception delivery is disabled
 792     _trace_flag              = 0x00000004U, // call tracing backend
 793     _obj_deopt               = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 794   };
 795 
 796   // various suspension related flags - atomically updated
 797   // overloaded with async exceptions so that we do a single check when transitioning from native->Java
 798   volatile uint32_t _suspend_flags;
 799 
 800   inline void set_suspend_flag(SuspendFlags f);
 801   inline void clear_suspend_flag(SuspendFlags f);
 802 
 803  public:
 804   inline void set_trace_flag();
 805   inline void clear_trace_flag();
 806   inline void set_obj_deopt_flag();
 807   inline void clear_obj_deopt_flag();
 808   bool is_trace_suspend()      { return (_suspend_flags & _trace_flag) != 0; }
 809   bool is_obj_deopt_suspend()  { return (_suspend_flags & _obj_deopt) != 0; }
 810 
 811   // Asynchronous exceptions support
 812  private:
 813   oop     _pending_async_exception;
 814 #ifdef ASSERT
 815   bool    _is_unsafe_access_error;
 816 #endif
 817 
 818   inline bool clear_async_exception_condition();
 819  public:
 820   bool has_async_exception_condition() {
 821     return (_suspend_flags & _has_async_exception) != 0 &&
 822            (_suspend_flags & _async_delivery_disabled) == 0;
 823   }
 824   inline void set_pending_async_exception(oop e);
 825   inline void set_pending_unsafe_access_error();
 826   static void send_async_exception(JavaThread* jt, oop java_throwable);
 827   void send_thread_stop(oop throwable);
 828   void check_and_handle_async_exceptions();
 829 
 830   class NoAsyncExceptionDeliveryMark : public StackObj {
 831     friend JavaThread;
 832     JavaThread *_target;
 833     inline NoAsyncExceptionDeliveryMark(JavaThread *t);
 834     inline ~NoAsyncExceptionDeliveryMark();
 835   };
 836 
 837   // Safepoint support
 838  public:                                                        // Expose _thread_state for SafeFetchInt()
 839   volatile JavaThreadState _thread_state;
 840  private:
 841   SafepointMechanism::ThreadData _poll_data;
 842   ThreadSafepointState*          _safepoint_state;              // Holds information about a thread during a safepoint
 843   address                        _saved_exception_pc;           // Saved pc of instruction where last implicit exception happened
 844   NOT_PRODUCT(bool               _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
 845 #ifdef ASSERT
 846   // Debug support for checking if code allows safepoints or not.
 847   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 848   // mutex, or blocking on an object synchronizer (Java locking).
 849   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 850   // the above cases. The class NoSafepointVerifier is used to set this counter.
 851   int _no_safepoint_count;                             // If 0, thread allow a safepoint to happen
 852 
 853  public:
 854   void inc_no_safepoint_count() { _no_safepoint_count++; }
 855   void dec_no_safepoint_count() { _no_safepoint_count--; }
 856 #endif // ASSERT
 857  public:
 858   // These functions check conditions before possibly going to a safepoint.
 859   // including NoSafepointVerifier.
 860   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 861   void check_possible_safepoint()        NOT_DEBUG_RETURN;
 862 
 863 #ifdef ASSERT
 864  private:
 865   volatile uint64_t _visited_for_critical_count;
 866 
 867  public:
 868   void set_visited_for_critical_count(uint64_t safepoint_id) {
 869     assert(_visited_for_critical_count == 0, "Must be reset before set");
 870     assert((safepoint_id & 0x1) == 1, "Must be odd");
 871     _visited_for_critical_count = safepoint_id;
 872   }
 873   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 874     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 875     _visited_for_critical_count = 0;
 876   }
 877   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 878     return _visited_for_critical_count == safepoint_id;
 879   }
 880 #endif // ASSERT
 881 
 882   // JavaThread termination support
 883  public:
 884   enum TerminatedTypes {
 885     _not_terminated = 0xDEAD - 2,
 886     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 887     _thread_terminated,                          // JavaThread is removed from thread list
 888     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 889                                                  // only VM_Exit can set _vm_exited
 890   };
 891 
 892  private:
 893   // In general a JavaThread's _terminated field transitions as follows:
 894   //
 895   //   _not_terminated => _thread_exiting => _thread_terminated
 896   //
 897   // _vm_exited is a special value to cover the case of a JavaThread
 898   // executing native code after the VM itself is terminated.
 899   volatile TerminatedTypes _terminated;
 900 
 901   jint                  _in_deopt_handler;       // count of deoptimization
 902                                                  // handlers thread is in
 903   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 904   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 905                                                          // never locked) when throwing an exception. Used by interpreter only.
 906 
 907   // JNI attach states:
 908   enum JNIAttachStates {
 909     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 910     _attaching_via_jni,          // thread is attaching via JNI
 911     _attached_via_jni            // thread has attached via JNI
 912   };
 913 
 914   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 915   // A native thread that is attaching via JNI starts with a value
 916   // of _attaching_via_jni and transitions to _attached_via_jni.
 917   volatile JNIAttachStates _jni_attach_state;
 918 
 919 
 920 #if INCLUDE_JVMCI
 921   // The _pending_* fields below are used to communicate extra information
 922   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 923 
 924   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 925   int       _pending_deoptimization;
 926 
 927   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 928   // before the monitor has been acquired.
 929   bool      _pending_monitorenter;
 930 
 931   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 932   bool      _pending_transfer_to_interpreter;
 933 
 934   // True if in a runtime call from compiled code that will deoptimize
 935   // and re-execute a failed heap allocation in the interpreter.
 936   bool      _in_retryable_allocation;
 937 
 938   // An id of a speculation that JVMCI compiled code can use to further describe and
 939   // uniquely identify the speculative optimization guarded by an uncommon trap.
 940   // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
 941   jlong     _pending_failed_speculation;
 942 
 943   // These fields are mutually exclusive in terms of live ranges.
 944   union {
 945     // Communicates the pc at which the most recent implicit exception occurred
 946     // from the signal handler to a deoptimization stub.
 947     address   _implicit_exception_pc;
 948 
 949     // Communicates an alternative call target to an i2c stub from a JavaCall .
 950     address   _alternate_call_target;
 951   } _jvmci;
 952 
 953   // Support for high precision, thread sensitive counters in JVMCI compiled code.
 954   jlong*    _jvmci_counters;
 955 
 956   // Fast thread locals for use by JVMCI
 957   jlong      _jvmci_reserved0;
 958   jlong      _jvmci_reserved1;
 959   oop        _jvmci_reserved_oop0;
 960 
 961  public:
 962   static jlong* _jvmci_old_thread_counters;
 963   static void collect_counters(jlong* array, int length);
 964 
 965   bool resize_counters(int current_size, int new_size);
 966 
 967   static bool resize_all_jvmci_counters(int new_size);
 968 
 969   void set_jvmci_reserved_oop0(oop value) {
 970     _jvmci_reserved_oop0 = value;
 971   }
 972 
 973   oop get_jvmci_reserved_oop0() {
 974     return _jvmci_reserved_oop0;
 975   }
 976 
 977   void set_jvmci_reserved0(jlong value) {
 978     _jvmci_reserved0 = value;
 979   }
 980 
 981   jlong get_jvmci_reserved0() {
 982     return _jvmci_reserved0;
 983   }
 984 
 985   void set_jvmci_reserved1(jlong value) {
 986     _jvmci_reserved1 = value;
 987   }
 988 
 989   jlong get_jvmci_reserved1() {
 990     return _jvmci_reserved1;
 991   }
 992 
 993  private:
 994 #endif // INCLUDE_JVMCI
 995 
 996   StackOverflow    _stack_overflow_state;
 997 
 998   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 999   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1000   // code)
1001   volatile oop     _exception_oop;               // Exception thrown in compiled code
1002   volatile address _exception_pc;                // PC where exception happened
1003   volatile address _exception_handler_pc;        // PC for handler of exception
1004   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1005 
1006  private:
1007   // support for JNI critical regions
1008   jint    _jni_active_critical;                  // count of entries into JNI critical region
1009 
1010   // Checked JNI: function name requires exception check
1011   char* _pending_jni_exception_check_fn;
1012 
1013   // For deadlock detection.
1014   int _depth_first_number;
1015 
1016   // JVMTI PopFrame support
1017   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1018   int _popframe_condition;
1019 
1020   // If reallocation of scalar replaced objects fails, we throw OOM
1021   // and during exception propagation, pop the top
1022   // _frames_to_pop_failed_realloc frames, the ones that reference
1023   // failed reallocations.
1024   int _frames_to_pop_failed_realloc;
1025 
1026   friend class VMThread;
1027   friend class ThreadWaitTransition;
1028   friend class VM_Exit;
1029 
1030   // Stack watermark barriers.
1031   StackWatermarks _stack_watermarks;
1032 
1033  public:
1034   inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
1035 
1036  public:
1037   // Constructor
1038   JavaThread();                            // delegating constructor
1039   JavaThread(bool is_attaching_via_jni);   // for main thread and JNI attached threads
1040   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1041   ~JavaThread();
1042 
1043 #ifdef ASSERT
1044   // verify this JavaThread hasn't be published in the Threads::list yet
1045   void verify_not_published();
1046 #endif // ASSERT
1047 
1048   StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
1049 
1050   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1051   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1052     _jni_environment.functions = functionTable;
1053   }
1054   struct JNINativeInterface_* get_jni_functions() {
1055     return (struct JNINativeInterface_ *)_jni_environment.functions;
1056   }
1057 
1058   // This function is called at thread creation to allow
1059   // platform specific thread variables to be initialized.
1060   void cache_global_variables();
1061 
1062   // Executes Shutdown.shutdown()
1063   void invoke_shutdown_hooks();
1064 
1065   // Cleanup on thread exit
1066   enum ExitType {
1067     normal_exit,
1068     jni_detach
1069   };
1070   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1071 
1072   void cleanup_failed_attach_current_thread(bool is_daemon);
1073 
1074   // Testers
1075   virtual bool is_Java_thread() const            { return true;  }
1076   virtual bool can_call_java() const             { return true; }
1077 
1078   virtual bool is_active_Java_thread() const {
1079     return on_thread_list() && !is_terminated();
1080   }
1081 
1082   // Thread oop. threadObj() can be NULL for initial JavaThread
1083   // (or for threads attached via JNI)
1084   oop threadObj() const;
1085   void set_threadObj(oop p);
1086 
1087   // Prepare thread and add to priority queue.  If a priority is
1088   // not specified, use the priority of the thread object. Threads_lock
1089   // must be held while this function is called.
1090   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1091 
1092   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1093   address saved_exception_pc()                   { return _saved_exception_pc; }
1094 
1095   ThreadFunction entry_point() const             { return _entry_point; }
1096 
1097   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1098   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1099 
1100   // Last frame anchor routines
1101 
1102   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1103 
1104   // last_Java_sp
1105   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1106   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1107 
1108   // last_Java_pc
1109 
1110   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1111 
1112   // Safepoint support
1113   inline JavaThreadState thread_state() const;
1114   inline void set_thread_state(JavaThreadState s);
1115   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
1116   inline ThreadSafepointState* safepoint_state() const;
1117   inline void set_safepoint_state(ThreadSafepointState* state);
1118   inline bool is_at_poll_safepoint();
1119 
1120   // JavaThread termination and lifecycle support:
1121   void smr_delete();
1122   bool on_thread_list() const { return _on_thread_list; }
1123   void set_on_thread_list() { _on_thread_list = true; }
1124 
1125   // thread has called JavaThread::exit() or is terminated
1126   bool is_exiting() const;
1127   // thread is terminated (no longer on the threads list); we compare
1128   // against the two non-terminated values so that a freed JavaThread
1129   // will also be considered terminated.
1130   bool check_is_terminated(TerminatedTypes l_terminated) const {
1131     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1132   }
1133   bool is_terminated() const;
1134   void set_terminated(TerminatedTypes t);
1135 
1136   void block_if_vm_exited();
1137 
1138   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1139   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1140 
1141   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1142   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1143 
1144   SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
1145 
1146   void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
1147 
1148  private:
1149   DEBUG_ONLY(void verify_frame_info();)
1150 
1151   // Support for thread handshake operations
1152   HandshakeState _handshake;
1153  public:
1154   HandshakeState* handshake_state() { return &_handshake; }
1155 
1156   // A JavaThread can always safely operate on it self and other threads
1157   // can do it safely if they are the active handshaker.
1158   bool is_handshake_safe_for(Thread* th) const {
1159     return _handshake.active_handshaker() == th || this == th;
1160   }
1161 
1162   // Suspend/resume support for JavaThread
1163   bool java_suspend(); // higher-level suspension logic called by the public APIs
1164   bool java_resume();  // higher-level resume logic called by the public APIs
1165   bool is_suspended()     { return _handshake.is_suspended(); }
1166 
1167   // Check for async exception in addition to safepoint.
1168   static void check_special_condition_for_native_trans(JavaThread *thread);
1169 
1170   // Synchronize with another thread that is deoptimizing objects of the
1171   // current thread, i.e. reverts optimizations based on escape analysis.
1172   void wait_for_object_deoptimization();
1173 
1174   // these next two are also used for self-suspension and async exception support
1175   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1176 
1177   // Return true if JavaThread has an asynchronous condition or
1178   // if external suspension is requested.
1179   bool has_special_runtime_exit_condition() {
1180     return (_suspend_flags & (_has_async_exception | _obj_deopt JFR_ONLY(| _trace_flag))) != 0;
1181   }
1182 
1183   // Fast-locking support
1184   bool is_lock_owned(address adr) const;
1185 
1186   // Accessors for vframe array top
1187   // The linked list of vframe arrays are sorted on sp. This means when we
1188   // unpack the head must contain the vframe array to unpack.
1189   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1190   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1191 
1192   // Side structure for deferring update of java frame locals until deopt occurs
1193   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
1194   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
1195 
1196   // These only really exist to make debugging deopt problems simpler
1197 
1198   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1199   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1200 
1201   // The special resourceMark used during deoptimization
1202 
1203   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1204   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1205 
1206   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1207   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1208 
1209   Method*    callee_target() const               { return _callee_target; }
1210   void set_callee_target  (Method* x)          { _callee_target   = x; }
1211 
1212   // Oop results of vm runtime calls
1213   oop  vm_result() const                         { return _vm_result; }
1214   void set_vm_result  (oop x)                    { _vm_result   = x; }
1215 
1216   Metadata*    vm_result_2() const               { return _vm_result_2; }
1217   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1218 
1219   oop return_buffered_value() const              { return _return_buffered_value; }
1220   void set_return_buffered_value(oop val)        { _return_buffered_value = val; }
1221 
1222   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1223   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1224 
1225 #if INCLUDE_JVMCI
1226   int  pending_deoptimization() const             { return _pending_deoptimization; }
1227   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
1228   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1229   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1230   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1231   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
1232   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1233   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1234   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1235 
1236   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
1237   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
1238 #endif // INCLUDE_JVMCI
1239 
1240   // Exception handling for compiled methods
1241   oop      exception_oop() const;
1242   address  exception_pc() const                  { return _exception_pc; }
1243   address  exception_handler_pc() const          { return _exception_handler_pc; }
1244   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1245 
1246   void set_exception_oop(oop o);
1247   void set_exception_pc(address a)               { _exception_pc = a; }
1248   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1249   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1250 
1251   void clear_exception_oop_and_pc() {
1252     set_exception_oop(NULL);
1253     set_exception_pc(NULL);
1254   }
1255 
1256   // Check if address is in the usable part of the stack (excludes protected
1257   // guard pages). Can be applied to any thread and is an approximation for
1258   // using is_in_live_stack when the query has to happen from another thread.
1259   bool is_in_usable_stack(address adr) const {
1260     return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
1261   }
1262 
1263   // Misc. accessors/mutators
1264   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1265   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1266   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1267 
1268   // For assembly stub generation
1269   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1270   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1271   static ByteSize pending_jni_exception_check_fn_offset() {
1272     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1273   }
1274   static ByteSize last_Java_sp_offset() {
1275     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1276   }
1277   static ByteSize last_Java_pc_offset() {
1278     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1279   }
1280   static ByteSize frame_anchor_offset() {
1281     return byte_offset_of(JavaThread, _anchor);
1282   }
1283   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1284   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1285   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1286   static ByteSize return_buffered_value_offset() { return byte_offset_of(JavaThread, _return_buffered_value); }
1287   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1288   static ByteSize polling_word_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_word);}
1289   static ByteSize polling_page_offset()          { return byte_offset_of(JavaThread, _poll_data) + byte_offset_of(SafepointMechanism::ThreadData, _polling_page);}
1290   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1291   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1292 #if INCLUDE_JVMCI
1293   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1294   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1295   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1296   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1297   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1298   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1299 #endif // INCLUDE_JVMCI
1300   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1301   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1302   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1303   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1304 
1305   static ByteSize active_handles_offset()        { return byte_offset_of(JavaThread, _active_handles); }
1306 
1307   // StackOverflow offsets
1308   static ByteSize stack_overflow_limit_offset()  {
1309     return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
1310   }
1311   static ByteSize stack_guard_state_offset()     {
1312     return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
1313   }
1314   static ByteSize reserved_stack_activation_offset() {
1315     return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
1316   }
1317   static ByteSize shadow_zone_safe_limit()  {
1318     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
1319   }
1320   static ByteSize shadow_zone_growth_watermark()  {
1321     return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
1322   }
1323 
1324   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1325 
1326   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1327   static ByteSize should_post_on_exceptions_flag_offset() {
1328     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1329   }
1330   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
1331   NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset()  { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
1332 
1333   // Returns the jni environment for this thread
1334   JNIEnv* jni_environment()                      { return &_jni_environment; }
1335 
1336   // Returns the current thread as indicated by the given JNIEnv.
1337   // We don't assert it is Thread::current here as that is done at the
1338   // external JNI entry points where the JNIEnv is passed into the VM.
1339   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1340     JavaThread* current = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1341     // We can't normally get here in a thread that has completed its
1342     // execution and so "is_terminated", except when the call is from
1343     // AsyncGetCallTrace, which can be triggered by a signal at any point in
1344     // a thread's lifecycle. A thread is also considered terminated if the VM
1345     // has exited, so we have to check this and block in case this is a daemon
1346     // thread returning to the VM (the JNI DirectBuffer entry points rely on
1347     // this).
1348     if (current->is_terminated()) {
1349       current->block_if_vm_exited();
1350     }
1351     return current;
1352   }
1353 
1354   // JNI critical regions. These can nest.
1355   bool in_critical()    { return _jni_active_critical > 0; }
1356   bool in_last_critical()  { return _jni_active_critical == 1; }
1357   inline void enter_critical();
1358   void exit_critical() {
1359     assert(Thread::current() == this, "this must be current thread");
1360     _jni_active_critical--;
1361     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1362   }
1363 
1364   // Checked JNI: is the programmer required to check for exceptions, if so specify
1365   // which function name. Returning to a Java frame should implicitly clear the
1366   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1367   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1368   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1369   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1370   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1371   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1372   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1373 
1374   // For deadlock detection
1375   int depth_first_number() { return _depth_first_number; }
1376   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1377 
1378  private:
1379   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1380 
1381  public:
1382   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1383   void add_monitor_chunk(MonitorChunk* chunk);
1384   void remove_monitor_chunk(MonitorChunk* chunk);
1385   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1386   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1387   void dec_in_deopt_handler() {
1388     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1389     if (_in_deopt_handler > 0) { // robustness
1390       _in_deopt_handler--;
1391     }
1392   }
1393 
1394  private:
1395   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1396 
1397   // factor out low-level mechanics for use in both normal and error cases
1398   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1399 
1400  public:
1401 
1402   // Frame iteration; calls the function f for all frames on the stack
1403   void frames_do(void f(frame*, const RegisterMap*));
1404 
1405   // Memory operations
1406   void oops_do_frames(OopClosure* f, CodeBlobClosure* cf);
1407   void oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf);
1408 
1409   // Sweeper operations
1410   virtual void nmethods_do(CodeBlobClosure* cf);
1411 
1412   // RedefineClasses Support
1413   void metadata_do(MetadataClosure* f);
1414 
1415   // Debug method asserting thread states are correct during a handshake operation.
1416   DEBUG_ONLY(void verify_states_for_handshake();)
1417 
1418   // Misc. operations
1419   const char* name() const;
1420   const char* type_name() const { return "JavaThread"; }
1421   static const char* name_for(oop thread_obj);
1422 
1423   void print_on(outputStream* st, bool print_extended_info) const;
1424   void print_on(outputStream* st) const { print_on(st, false); }
1425   void print() const;
1426   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1427   void print_on_error(outputStream* st, char* buf, int buflen) const;
1428   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1429   void verify();
1430 
1431   // Accessing frames
1432   frame last_frame() {
1433     _anchor.make_walkable(this);
1434     return pd_last_frame();
1435   }
1436   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1437 
1438   // Returns method at 'depth' java or native frames down the stack
1439   // Used for security checks
1440   Klass* security_get_caller_class(int depth);
1441 
1442   // Print stack trace in external format
1443   void print_stack_on(outputStream* st);
1444   void print_stack() { print_stack_on(tty); }
1445 
1446   // Print stack traces in various internal formats
1447   void trace_stack()                             PRODUCT_RETURN;
1448   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1449   void trace_frames()                            PRODUCT_RETURN;
1450 
1451   // Print an annotated view of the stack frames
1452   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1453   void validate_frame_layout() {
1454     print_frame_layout(0, true);
1455   }
1456 
1457   // Function for testing deoptimization
1458   void deoptimize();
1459   void make_zombies();
1460 
1461   void deoptimize_marked_methods();
1462 
1463  public:
1464   // Returns the running thread as a JavaThread
1465   static JavaThread* current() {
1466     return JavaThread::cast(Thread::current());
1467   }
1468 
1469   // Returns the current thread as a JavaThread, or NULL if not attached
1470   static inline JavaThread* current_or_null();
1471 
1472   // Casts
1473   static JavaThread* cast(Thread* t) {
1474     assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1475     return static_cast<JavaThread*>(t);
1476   }
1477 
1478   static const JavaThread* cast(const Thread* t) {
1479     assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1480     return static_cast<const JavaThread*>(t);
1481   }
1482 
1483   // Returns the active Java thread.  Do not use this if you know you are calling
1484   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1485   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1486   // operation.  You may not want that either.
1487   static JavaThread* active();
1488 
1489  protected:
1490   virtual void pre_run();
1491   virtual void run();
1492   void thread_main_inner();
1493   virtual void post_run();
1494 
1495  public:
1496   // Thread local information maintained by JVMTI.
1497   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1498   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1499   // getter is used to get this JavaThread's JvmtiThreadState if it has
1500   // one which means NULL can be returned. JvmtiThreadState::state_for()
1501   // is used to get the specified JavaThread's JvmtiThreadState if it has
1502   // one or it allocates a new JvmtiThreadState for the JavaThread and
1503   // returns it. JvmtiThreadState::state_for() will return NULL only if
1504   // the specified JavaThread is exiting.
1505   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1506   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1507 
1508   // JVMTI PopFrame support
1509   // Setting and clearing popframe_condition
1510   // All of these enumerated values are bits. popframe_pending
1511   // indicates that a PopFrame() has been requested and not yet been
1512   // completed. popframe_processing indicates that that PopFrame() is in
1513   // the process of being completed. popframe_force_deopt_reexecution_bit
1514   // indicates that special handling is required when returning to a
1515   // deoptimized caller.
1516   enum PopCondition {
1517     popframe_inactive                      = 0x00,
1518     popframe_pending_bit                   = 0x01,
1519     popframe_processing_bit                = 0x02,
1520     popframe_force_deopt_reexecution_bit   = 0x04
1521   };
1522   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1523   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1524   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1525   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1526   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1527   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1528   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1529   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1530 
1531   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1532   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1533   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1534 
1535   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1536   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1537   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1538 
1539  private:
1540   // Saved incoming arguments to popped frame.
1541   // Used only when popped interpreted frame returns to deoptimized frame.
1542   void*    _popframe_preserved_args;
1543   int      _popframe_preserved_args_size;
1544 
1545  public:
1546   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1547   void* popframe_preserved_args();
1548   ByteSize popframe_preserved_args_size();
1549   WordSize popframe_preserved_args_size_in_words();
1550   void  popframe_free_preserved_args();
1551 
1552 
1553  private:
1554   JvmtiThreadState *_jvmti_thread_state;
1555 
1556   // Used by the interpreter in fullspeed mode for frame pop, method
1557   // entry, method exit and single stepping support. This field is
1558   // only set to non-zero at a safepoint or using a direct handshake
1559   // (see EnterInterpOnlyModeClosure).
1560   // It can be set to zero asynchronously to this threads execution (i.e., without
1561   // safepoint/handshake or a lock) so we have to be very careful.
1562   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1563   int               _interp_only_mode;
1564 
1565  public:
1566   // used by the interpreter for fullspeed debugging support (see above)
1567   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1568   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1569   int get_interp_only_mode()                { return _interp_only_mode; }
1570   void increment_interp_only_mode()         { ++_interp_only_mode; }
1571   void decrement_interp_only_mode()         { --_interp_only_mode; }
1572 
1573   // support for cached flag that indicates whether exceptions need to be posted for this thread
1574   // if this is false, we can avoid deoptimizing when events are thrown
1575   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1576  private:
1577   int    _should_post_on_exceptions_flag;
1578 
1579  public:
1580   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1581   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1582 
1583  private:
1584   ThreadStatistics *_thread_stat;
1585 
1586  public:
1587   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1588 
1589   // Return a blocker object for which this thread is blocked parking.
1590   oop current_park_blocker();
1591 
1592  private:
1593   static size_t _stack_size_at_create;
1594 
1595  public:
1596   static inline size_t stack_size_at_create(void) {
1597     return _stack_size_at_create;
1598   }
1599   static inline void set_stack_size_at_create(size_t value) {
1600     _stack_size_at_create = value;
1601   }
1602 
1603   // Machine dependent stuff
1604 #include OS_CPU_HEADER(thread)
1605 
1606   // JSR166 per-thread parker
1607  private:
1608   Parker _parker;
1609  public:
1610   Parker* parker() { return &_parker; }
1611 
1612  public:
1613   // clearing/querying jni attach status
1614   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1615   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1616   inline void set_done_attaching_via_jni();
1617 
1618   // Stack dump assistance:
1619   // Track the class we want to initialize but for which we have to wait
1620   // on its init_lock() because it is already being initialized.
1621   void set_class_to_be_initialized(InstanceKlass* k);
1622   InstanceKlass* class_to_be_initialized() const;
1623 
1624 private:
1625   InstanceKlass* _class_to_be_initialized;
1626 
1627   // java.lang.Thread.sleep support
1628   ParkEvent * _SleepEvent;
1629 public:
1630   bool sleep(jlong millis);
1631 
1632   // java.lang.Thread interruption support
1633   void interrupt();
1634   bool is_interrupted(bool clear_interrupted);
1635 
1636   static OopStorage* thread_oop_storage();
1637 
1638   static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1639 
1640   // Helper function to create the java.lang.Thread object for a
1641   // VM-internal thread. The thread will have the given name, be
1642   // part of the System ThreadGroup and if is_visible is true will be
1643   // discoverable via the system ThreadGroup.
1644   static Handle create_system_thread_object(const char* name, bool is_visible, TRAPS);
1645 
1646   // Helper function to start a VM-internal daemon thread.
1647   // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1648   static void start_internal_daemon(JavaThread* current, JavaThread* target,
1649                                     Handle thread_oop, ThreadPriority prio);
1650 
1651   // Helper function to do vm_exit_on_initialization for osthread
1652   // resource allocation failure.
1653   static void vm_exit_on_osthread_failure(JavaThread* thread);
1654 };
1655 
1656 inline JavaThread* JavaThread::current_or_null() {
1657   Thread* current = Thread::current_or_null();
1658   return current != nullptr ? JavaThread::cast(current) : nullptr;
1659 }
1660 
1661 // The active thread queue. It also keeps track of the current used
1662 // thread priorities.
1663 class Threads: AllStatic {
1664   friend class VMStructs;
1665  private:
1666   static int         _number_of_threads;
1667   static int         _number_of_non_daemon_threads;
1668   static int         _return_code;
1669   static uintx       _thread_claim_token;
1670 #ifdef ASSERT
1671   static bool        _vm_complete;
1672 #endif
1673 
1674   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
1675   static void initialize_jsr292_core_classes(TRAPS);
1676 
1677  public:
1678   // Thread management
1679   // force_daemon is a concession to JNI, where we may need to add a
1680   // thread to the thread list before allocating its thread object
1681   static void add(JavaThread* p, bool force_daemon = false);
1682   static void remove(JavaThread* p, bool is_daemon);
1683   static void non_java_threads_do(ThreadClosure* tc);
1684   static void java_threads_do(ThreadClosure* tc);
1685   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
1686   static void threads_do(ThreadClosure* tc);
1687   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
1688 
1689   // Initializes the vm and creates the vm thread
1690   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1691   static void convert_vm_init_libraries_to_agents();
1692   static void create_vm_init_libraries();
1693   static void create_vm_init_agents();
1694   static void shutdown_vm_agents();
1695   static void destroy_vm();
1696   // Supported VM versions via JNI
1697   // Includes JNI_VERSION_1_1
1698   static jboolean is_supported_jni_version_including_1_1(jint version);
1699   // Does not include JNI_VERSION_1_1
1700   static jboolean is_supported_jni_version(jint version);
1701 
1702   // The "thread claim token" provides a way for threads to be claimed
1703   // by parallel worker tasks.
1704   //
1705   // Each thread contains a "token" field. A task will claim the
1706   // thread only if its token is different from the global token,
1707   // which is updated by calling change_thread_claim_token().  When
1708   // a thread is claimed, it's token is set to the global token value
1709   // so other threads in the same iteration pass won't claim it.
1710   //
1711   // For this to work change_thread_claim_token() needs to be called
1712   // exactly once in sequential code before starting parallel tasks
1713   // that should claim threads.
1714   //
1715   // New threads get their token set to 0 and change_thread_claim_token()
1716   // never sets the global token to 0.
1717   static uintx thread_claim_token() { return _thread_claim_token; }
1718   static void change_thread_claim_token();
1719   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
1720 
1721   // Apply "f->do_oop" to all root oops in all threads.
1722   // This version may only be called by sequential code.
1723   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
1724   // This version may be called by sequential or parallel code.
1725   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
1726 
1727   // RedefineClasses support
1728   static void metadata_do(MetadataClosure* f);
1729   static void metadata_handles_do(void f(Metadata*));
1730 
1731 #ifdef ASSERT
1732   static bool is_vm_complete() { return _vm_complete; }
1733 #endif // ASSERT
1734 
1735   // Verification
1736   static void verify();
1737   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
1738   static void print(bool print_stacks, bool internal_format) {
1739     // this function is only used by debug.cpp
1740     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
1741   }
1742   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
1743   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
1744                              int buflen, bool* found_current);
1745   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
1746 
1747   // Get Java threads that are waiting to enter a monitor.
1748   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
1749                                                          int count, address monitor);
1750 
1751   // Get owning Java thread from the monitor's owner field.
1752   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
1753                                                       address owner);
1754 
1755   // Number of threads on the active threads list
1756   static int number_of_threads()                 { return _number_of_threads; }
1757   // Number of non-daemon threads on the active threads list
1758   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
1759 
1760   // Deoptimizes all frames tied to marked nmethods
1761   static void deoptimized_wrt_marked_nmethods();
1762 
1763   struct Test;                  // For private gtest access.
1764 };
1765 
1766 class UnlockFlagSaver {
1767   private:
1768     JavaThread* _thread;
1769     bool _do_not_unlock;
1770   public:
1771     UnlockFlagSaver(JavaThread* t) {
1772       _thread = t;
1773       _do_not_unlock = t->do_not_unlock_if_synchronized();
1774       t->set_do_not_unlock_if_synchronized(false);
1775     }
1776     ~UnlockFlagSaver() {
1777       _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1778     }
1779 };
1780 
1781 class JNIHandleMark : public StackObj {
1782   JavaThread* _thread;
1783  public:
1784   JNIHandleMark(JavaThread* thread) : _thread(thread) {
1785     thread->push_jni_handle_block();
1786   }
1787   ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1788 };
1789 
1790 #endif // SHARE_RUNTIME_THREAD_HPP