1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_THREAD_HPP
  26 #define SHARE_VM_RUNTIME_THREAD_HPP
  27 
  28 #include "jni.h"
  29 #include "gc/shared/gcThreadLocalData.hpp"
  30 #include "gc/shared/threadLocalAllocBuffer.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "oops/oop.hpp"
  33 #include "prims/jvmtiExport.hpp"
  34 #include "runtime/frame.hpp"
  35 #include "runtime/globals.hpp"
  36 #include "runtime/handshake.hpp"
  37 #include "runtime/javaFrameAnchor.hpp"
  38 #include "runtime/jniHandles.hpp"
  39 #include "runtime/mutexLocker.hpp"
  40 #include "runtime/os.hpp"
  41 #include "runtime/osThread.hpp"
  42 #include "runtime/park.hpp"
  43 #include "runtime/safepoint.hpp"
  44 #include "runtime/stubRoutines.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/macros.hpp"
  52 #ifdef ZERO
  53 # include "stack_zero.hpp"
  54 #endif
  55 #if INCLUDE_JFR
  56 #include "jfr/support/jfrThreadExtension.hpp"
  57 #endif
  58 
  59 
  60 class SafeThreadsListPtr;
  61 class ThreadSafepointState;
  62 class ThreadsList;
  63 class ThreadsSMRSupport;
  64 
  65 class JvmtiThreadState;
  66 class ThreadStatistics;
  67 class ConcurrentLocksDump;
  68 class ParkEvent;
  69 class Parker;
  70 
  71 class ciEnv;
  72 class CompileThread;
  73 class CompileLog;
  74 class CompileTask;
  75 class CompileQueue;
  76 class CompilerCounters;
  77 class vframeArray;
  78 
  79 class DeoptResourceMark;
  80 class jvmtiDeferredLocalVariableSet;
  81 
  82 class GCTaskQueue;
  83 class ThreadClosure;
  84 class IdealGraphPrinter;
  85 
  86 class Metadata;
  87 template <class T, MEMFLAGS F> class ChunkedList;
  88 typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;
  89 
  90 DEBUG_ONLY(class ResourceMark;)
  91 
  92 class WorkerThread;
  93 
  94 // Class hierarchy
  95 // - Thread
  96 //   - JavaThread
  97 //     - various subclasses eg CompilerThread, ServiceThread
  98 //   - NonJavaThread
  99 //     - NamedThread
 100 //       - VMThread
 101 //       - ConcurrentGCThread
 102 //       - WorkerThread
 103 //         - GangWorker
 104 //         - GCTaskThread
 105 //     - WatcherThread
 106 //     - JfrThreadSampler
 107 //
 108 // All Thread subclasses must be either JavaThread or NonJavaThread.
 109 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 110 // a partially constructed/destroyed Thread.
 111 
 112 class Thread: public ThreadShadow {
 113   friend class VMStructs;
 114   friend class JVMCIVMStructs;
 115  private:
 116 
 117 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 118   // Current thread is maintained as a thread-local variable
 119   static THREAD_LOCAL_DECL Thread* _thr_current;
 120 #endif
 121 
 122  private:
 123   // Thread local data area available to the GC. The internal
 124   // structure and contents of this data area is GC-specific.
 125   // Only GC and GC barrier code should access this data area.
 126   GCThreadLocalData _gc_data;
 127 
 128  public:
 129   static ByteSize gc_data_offset() {
 130     return byte_offset_of(Thread, _gc_data);
 131   }
 132 
 133   template <typename T> T* gc_data() {
 134     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 135     return reinterpret_cast<T*>(&_gc_data);
 136   }
 137 
 138   // Exception handling
 139   // (Note: _pending_exception and friends are in ThreadShadow)
 140   //oop       _pending_exception;                // pending exception for current thread
 141   // const char* _exception_file;                   // file information for exception (debugging only)
 142   // int         _exception_line;                   // line information for exception (debugging only)
 143  protected:
 144   // Support for forcing alignment of thread objects for biased locking
 145   void*       _real_malloc_address;
 146 
 147   // JavaThread lifecycle support:
 148   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
 149   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 150   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 151   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 152   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 153 
 154   ThreadsList* volatile _threads_hazard_ptr;
 155   SafeThreadsListPtr*   _threads_list_ptr;
 156   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 157   ThreadsList*          get_threads_hazard_ptr();
 158   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 159   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 160     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 161   }
 162   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 163     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 164   }
 165   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 166     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 167   }
 168   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 169   uint _nested_threads_hazard_ptr_cnt;
 170   void dec_nested_threads_hazard_ptr_cnt() {
 171     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 172     _nested_threads_hazard_ptr_cnt--;
 173   }
 174   void inc_nested_threads_hazard_ptr_cnt() {
 175     _nested_threads_hazard_ptr_cnt++;
 176   }
 177   uint nested_threads_hazard_ptr_cnt() {
 178     return _nested_threads_hazard_ptr_cnt;
 179   }
 180 
 181  public:
 182   void* operator new(size_t size) throw() { return allocate(size, true); }
 183   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 184     return allocate(size, false); }
 185   void  operator delete(void* p);
 186 
 187  protected:
 188   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 189  private:
 190 
 191   // ***************************************************************
 192   // Suspend and resume support
 193   // ***************************************************************
 194   //
 195   // VM suspend/resume no longer exists - it was once used for various
 196   // things including safepoints but was deprecated and finally removed
 197   // in Java 7. Because VM suspension was considered "internal" Java-level
 198   // suspension was considered "external", and this legacy naming scheme
 199   // remains.
 200   //
 201   // External suspend/resume requests come from JVM_SuspendThread,
 202   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 203   // ResumeThread. External
 204   // suspend requests cause _external_suspend to be set and external
 205   // resume requests cause _external_suspend to be cleared.
 206   // External suspend requests do not nest on top of other external
 207   // suspend requests. The higher level APIs reject suspend requests
 208   // for already suspended threads.
 209   //
 210   // The external_suspend
 211   // flag is checked by has_special_runtime_exit_condition() and java thread
 212   // will self-suspend when handle_special_runtime_exit_condition() is
 213   // called. Most uses of the _thread_blocked state in JavaThreads are
 214   // considered the same as being externally suspended; if the blocking
 215   // condition lifts, the JavaThread will self-suspend. Other places
 216   // where VM checks for external_suspend include:
 217   //   + mutex granting (do not enter monitors when thread is suspended)
 218   //   + state transitions from _thread_in_native
 219   //
 220   // In general, java_suspend() does not wait for an external suspend
 221   // request to complete. When it returns, the only guarantee is that
 222   // the _external_suspend field is true.
 223   //
 224   // wait_for_ext_suspend_completion() is used to wait for an external
 225   // suspend request to complete. External suspend requests are usually
 226   // followed by some other interface call that requires the thread to
 227   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 228   // the interface that requires quiescence, we give the JavaThread a
 229   // chance to self-suspend before we need it to be quiescent. This
 230   // improves overall suspend/query performance.
 231   //
 232   // _suspend_flags controls the behavior of java_ suspend/resume.
 233   // It must be set under the protection of SR_lock. Read from the flag is
 234   // OK without SR_lock as long as the value is only used as a hint.
 235   // (e.g., check _external_suspend first without lock and then recheck
 236   // inside SR_lock and finish the suspension)
 237   //
 238   // _suspend_flags is also overloaded for other "special conditions" so
 239   // that a single check indicates whether any special action is needed
 240   // eg. for async exceptions.
 241   // -------------------------------------------------------------------
 242   // Notes:
 243   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 244   // but we still update its value to keep other part of the system (mainly
 245   // JVMTI) happy. ThreadState is legacy code (see notes in
 246   // osThread.hpp).
 247   //
 248   // 2. It would be more natural if set_external_suspend() is private and
 249   // part of java_suspend(), but that probably would affect the suspend/query
 250   // performance. Need more investigation on this.
 251 
 252   // suspend/resume lock: used for self-suspend
 253   Monitor* _SR_lock;
 254 
 255  protected:
 256   enum SuspendFlags {
 257     // NOTE: avoid using the sign-bit as cc generates different test code
 258     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 259 
 260     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 261     _ext_suspended          = 0x40000000U, // thread has self-suspended
 262     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 263 
 264     _has_async_exception    = 0x00000001U, // there is a pending async exception
 265     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 266 
 267     _trace_flag             = 0x00000004U  // call tracing backend
 268   };
 269 
 270   // various suspension related flags - atomically updated
 271   // overloaded for async exception checking in check_special_condition_for_native_trans.
 272   volatile uint32_t _suspend_flags;
 273 
 274  private:
 275   int _num_nested_signal;
 276 
 277   DEBUG_ONLY(bool _suspendible_thread;)
 278 
 279  public:
 280   void enter_signal_handler() { _num_nested_signal++; }
 281   void leave_signal_handler() { _num_nested_signal--; }
 282   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 283 
 284 #ifdef ASSERT
 285   void set_suspendible_thread() {
 286     _suspendible_thread = true;
 287   }
 288 
 289   void clear_suspendible_thread() {
 290     _suspendible_thread = false;
 291   }
 292 
 293   bool is_suspendible_thread() { return _suspendible_thread; }
 294 #endif
 295 
 296  private:
 297   // Active_handles points to a block of handles
 298   JNIHandleBlock* _active_handles;
 299 
 300   // One-element thread local free list
 301   JNIHandleBlock* _free_handle_block;
 302 
 303   // Point to the last handle mark
 304   HandleMark* _last_handle_mark;
 305 
 306   // The parity of the last strong_roots iteration in which this thread was
 307   // claimed as a task.
 308   int _oops_do_parity;
 309 
 310   // Support for GlobalCounter
 311  private:
 312   volatile uintx _rcu_counter;
 313  public:
 314   volatile uintx* get_rcu_counter() {
 315     return &_rcu_counter;
 316   }
 317 
 318  public:
 319   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 320   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 321  private:
 322 
 323   // debug support for checking if code does allow safepoints or not
 324   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 325   // mutex, or blocking on an object synchronizer (Java locking).
 326   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 327   // If !allow_allocation(), then an assertion failure will happen during allocation
 328   // (Hence, !allow_safepoint() => !allow_allocation()).
 329   //
 330   // The two classes NoSafepointVerifier and No_Allocation_Verifier are used to set these counters.
 331   //
 332   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 333   debug_only(int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 334 
 335   // Used by SkipGCALot class.
 336   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 337 
 338   friend class NoAllocVerifier;
 339   friend class NoSafepointVerifier;
 340   friend class PauseNoSafepointVerifier;
 341   friend class GCLocker;
 342 
 343   volatile void* _polling_page;                 // Thread local polling page
 344 
 345   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 346   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 347                                                 // the Java heap
 348   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 349 
 350   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 351 
 352   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 353 
 354   int   _vm_operation_started_count;            // VM_Operation support
 355   int   _vm_operation_completed_count;          // VM_Operation support
 356 
 357   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 358                                                 // is waiting to lock
 359   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 360 
 361   // ObjectMonitor on which this thread called Object.wait()
 362   ObjectMonitor* _current_waiting_monitor;
 363 
 364   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 365  public:
 366   ObjectMonitor* omFreeList;
 367   int omFreeCount;                              // length of omFreeList
 368   int omFreeProvision;                          // reload chunk size
 369   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 370   int omInUseCount;                             // length of omInUseList
 371 
 372 #ifdef ASSERT
 373  private:
 374   bool _visited_for_critical_count;
 375 
 376  public:
 377   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 378   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 379 #endif
 380 
 381  public:
 382   enum {
 383     is_definitely_current_thread = true
 384   };
 385 
 386   // Constructor
 387   Thread();
 388   virtual ~Thread() = 0;        // Thread is abstract.
 389 
 390   // Manage Thread::current()
 391   void initialize_thread_current();
 392   void clear_thread_current(); // TLS cleanup needed before threads terminate
 393 
 394  public:
 395   // thread entry point
 396   virtual void run();
 397 
 398   // Testers
 399   virtual bool is_VM_thread()       const            { return false; }
 400   virtual bool is_Java_thread()     const            { return false; }
 401   virtual bool is_Compiler_thread() const            { return false; }
 402   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 403   virtual bool is_hidden_from_external_view() const  { return false; }
 404   virtual bool is_jvmti_agent_thread() const         { return false; }
 405   // True iff the thread can perform GC operations at a safepoint.
 406   // Generally will be true only of VM thread and parallel GC WorkGang
 407   // threads.
 408   virtual bool is_GC_task_thread() const             { return false; }
 409   virtual bool is_Watcher_thread() const             { return false; }
 410   virtual bool is_ConcurrentGC_thread() const        { return false; }
 411   virtual bool is_Named_thread() const               { return false; }
 412   virtual bool is_Worker_thread() const              { return false; }
 413 
 414   // Can this thread make Java upcalls
 415   virtual bool can_call_java() const                 { return false; }
 416 
 417   // Casts
 418   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 419 
 420   virtual char* name() const { return (char*)"Unknown thread"; }
 421 
 422   // Returns the current thread (ASSERTS if NULL)
 423   static inline Thread* current();
 424   // Returns the current thread, or NULL if not attached
 425   static inline Thread* current_or_null();
 426   // Returns the current thread, or NULL if not attached, and is
 427   // safe for use from signal-handlers
 428   static inline Thread* current_or_null_safe();
 429 
 430   // Common thread operations
 431 #ifdef ASSERT
 432   static void check_for_dangling_thread_pointer(Thread *thread);
 433 #endif
 434   static void set_priority(Thread* thread, ThreadPriority priority);
 435   static ThreadPriority get_priority(const Thread* const thread);
 436   static void start(Thread* thread);
 437   static void interrupt(Thread* thr);
 438   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 439 
 440   void set_native_thread_name(const char *name) {
 441     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 442     os::set_native_thread_name(name);
 443   }
 444 
 445   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 446   Monitor* SR_lock() const                       { return _SR_lock; }
 447 
 448   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 449 
 450   inline void set_suspend_flag(SuspendFlags f);
 451   inline void clear_suspend_flag(SuspendFlags f);
 452 
 453   inline void set_has_async_exception();
 454   inline void clear_has_async_exception();
 455 
 456   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 457 
 458   inline void set_critical_native_unlock();
 459   inline void clear_critical_native_unlock();
 460 
 461   inline void set_trace_flag();
 462   inline void clear_trace_flag();
 463 
 464   // Support for Unhandled Oop detection
 465   // Add the field for both, fastdebug and debug, builds to keep
 466   // Thread's fields layout the same.
 467   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 468 #ifdef CHECK_UNHANDLED_OOPS
 469  private:
 470   UnhandledOops* _unhandled_oops;
 471 #elif defined(ASSERT)
 472  private:
 473   void* _unhandled_oops;
 474 #endif
 475 #ifdef CHECK_UNHANDLED_OOPS
 476  public:
 477   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 478   // Mark oop safe for gc.  It may be stack allocated but won't move.
 479   void allow_unhandled_oop(oop *op) {
 480     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 481   }
 482   // Clear oops at safepoint so crashes point to unhandled oop violator
 483   void clear_unhandled_oops() {
 484     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 485   }
 486 #endif // CHECK_UNHANDLED_OOPS
 487 
 488  public:
 489 #ifndef PRODUCT
 490   bool skip_gcalot()           { return _skip_gcalot; }
 491   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 492 #endif
 493 
 494   // Installs a pending exception to be inserted later
 495   static void send_async_exception(oop thread_oop, oop java_throwable);
 496 
 497   // Resource area
 498   ResourceArea* resource_area() const            { return _resource_area; }
 499   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 500 
 501   OSThread* osthread() const                     { return _osthread;   }
 502   void set_osthread(OSThread* thread)            { _osthread = thread; }
 503 
 504   // JNI handle support
 505   JNIHandleBlock* active_handles() const         { return _active_handles; }
 506   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 507   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 508   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 509 
 510   // Internal handle support
 511   HandleArea* handle_area() const                { return _handle_area; }
 512   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 513 
 514   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 515   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 516 
 517   // Thread-Local Allocation Buffer (TLAB) support
 518   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 519   void initialize_tlab() {
 520     if (UseTLAB) {
 521       tlab().initialize();
 522     }
 523   }
 524 
 525   jlong allocated_bytes()               { return _allocated_bytes; }
 526   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 527   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 528   inline jlong cooked_allocated_bytes();
 529 
 530   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 531 
 532   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 533 
 534   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 535 
 536   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 537 
 538   // VM operation support
 539   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 540   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 541   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 542 
 543   // For tracking the heavyweight monitor the thread is pending on.
 544   ObjectMonitor* current_pending_monitor() {
 545     return _current_pending_monitor;
 546   }
 547   void set_current_pending_monitor(ObjectMonitor* monitor) {
 548     _current_pending_monitor = monitor;
 549   }
 550   void set_current_pending_monitor_is_from_java(bool from_java) {
 551     _current_pending_monitor_is_from_java = from_java;
 552   }
 553   bool current_pending_monitor_is_from_java() {
 554     return _current_pending_monitor_is_from_java;
 555   }
 556 
 557   // For tracking the ObjectMonitor on which this thread called Object.wait()
 558   ObjectMonitor* current_waiting_monitor() {
 559     return _current_waiting_monitor;
 560   }
 561   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 562     _current_waiting_monitor = monitor;
 563   }
 564 
 565   // GC support
 566   // Apply "f->do_oop" to all root oops in "this".
 567   //   Used by JavaThread::oops_do.
 568   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 569   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 570 
 571   // Handles the parallel case for the method below.
 572  private:
 573   bool claim_oops_do_par_case(int collection_parity);
 574  public:
 575   // Requires that "collection_parity" is that of the current roots
 576   // iteration.  If "is_par" is false, sets the parity of "this" to
 577   // "collection_parity", and returns "true".  If "is_par" is true,
 578   // uses an atomic instruction to set the current threads parity to
 579   // "collection_parity", if it is not already.  Returns "true" iff the
 580   // calling thread does the update, this indicates that the calling thread
 581   // has claimed the thread's stack as a root groop in the current
 582   // collection.
 583   bool claim_oops_do(bool is_par, int collection_parity) {
 584     if (!is_par) {
 585       _oops_do_parity = collection_parity;
 586       return true;
 587     } else {
 588       return claim_oops_do_par_case(collection_parity);
 589     }
 590   }
 591 
 592   // jvmtiRedefineClasses support
 593   void metadata_handles_do(void f(Metadata*));
 594 
 595   // Used by fast lock support
 596   virtual bool is_lock_owned(address adr) const;
 597 
 598   // Check if address is in the stack of the thread (not just for locks).
 599   // Warning: the method can only be used on the running thread
 600   bool is_in_stack(address adr) const;
 601   // Check if address is in the usable part of the stack (excludes protected
 602   // guard pages)
 603   bool is_in_usable_stack(address adr) const;
 604 
 605   // Sets this thread as starting thread. Returns failure if thread
 606   // creation fails due to lack of memory, too many threads etc.
 607   bool set_as_starting_thread();
 608 
 609 protected:
 610   // OS data associated with the thread
 611   OSThread* _osthread;  // Platform-specific thread information
 612 
 613   // Thread local resource area for temporary allocation within the VM
 614   ResourceArea* _resource_area;
 615 
 616   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 617 
 618   // Thread local handle area for allocation of handles within the VM
 619   HandleArea* _handle_area;
 620   GrowableArray<Metadata*>* _metadata_handles;
 621 
 622   // Support for stack overflow handling, get_thread, etc.
 623   address          _stack_base;
 624   size_t           _stack_size;
 625   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 626   int              _lgrp_id;
 627 
 628   volatile void** polling_page_addr() { return &_polling_page; }
 629 
 630  public:
 631   // Stack overflow support
 632   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 633   void    set_stack_base(address base) { _stack_base = base; }
 634   size_t  stack_size() const           { return _stack_size; }
 635   void    set_stack_size(size_t size)  { _stack_size = size; }
 636   address stack_end()  const           { return stack_base() - stack_size(); }
 637   void    record_stack_base_and_size();
 638 
 639   bool    on_local_stack(address adr) const {
 640     // QQQ this has knowledge of direction, ought to be a stack method
 641     return (_stack_base >= adr && adr >= stack_end());
 642   }
 643 
 644   uintptr_t self_raw_id()                    { return _self_raw_id; }
 645   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 646 
 647   int     lgrp_id() const        { return _lgrp_id; }
 648   void    set_lgrp_id(int value) { _lgrp_id = value; }
 649 
 650   // Printing
 651   void print_on(outputStream* st, bool print_extended_info) const;
 652   virtual void print_on(outputStream* st) const { print_on(st, false); }
 653   void print() const { print_on(tty); }
 654   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 655   void print_value_on(outputStream* st) const;
 656 
 657   // Debug-only code
 658 #ifdef ASSERT
 659  private:
 660   // Deadlock detection support for Mutex locks. List of locks own by thread.
 661   Monitor* _owned_locks;
 662   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 663   // thus the friendship
 664   friend class Mutex;
 665   friend class Monitor;
 666 
 667  public:
 668   void print_owned_locks_on(outputStream* st) const;
 669   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 670   Monitor* owned_locks() const                   { return _owned_locks;          }
 671   bool owns_locks() const                        { return owned_locks() != NULL; }
 672   bool owns_locks_but_compiled_lock() const;
 673   int oops_do_parity() const                     { return _oops_do_parity; }
 674 
 675   // Deadlock detection
 676   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 677   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 678   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 679 #endif
 680 
 681   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 682 
 683  private:
 684   volatile int _jvmti_env_iteration_count;
 685 
 686  public:
 687   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 688   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 689   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 690 
 691   // Code generation
 692   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 693   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 694   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 695 
 696   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 697   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 698 
 699   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 700 
 701   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 702   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 703   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 704   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 705 
 706   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 707 
 708   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 709 
 710  public:
 711   volatile intptr_t _Stalled;
 712   volatile int _TypeTag;
 713   ParkEvent * _ParkEvent;                     // for synchronized()
 714   ParkEvent * _SleepEvent;                    // for Thread.sleep
 715   ParkEvent * _MutexEvent;                    // for native internal Mutex/Monitor
 716   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 717   int NativeSyncRecursion;                    // diagnostic
 718 
 719   volatile int _OnTrap;                       // Resume-at IP delta
 720   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 721   jint _hashStateX;                           // thread-specific hashCode generator state
 722   jint _hashStateY;
 723   jint _hashStateZ;
 724 
 725   volatile jint rng[4];                      // RNG for spin loop
 726 
 727   // Low-level leaf-lock primitives used to implement synchronization
 728   // and native monitor-mutex infrastructure.
 729   // Not for general synchronization use.
 730   static void SpinAcquire(volatile int * Lock, const char * Name);
 731   static void SpinRelease(volatile int * Lock);
 732   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 733   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 734   static void muxRelease(volatile intptr_t * Lock);
 735 };
 736 
 737 // Inline implementation of Thread::current()
 738 inline Thread* Thread::current() {
 739   Thread* current = current_or_null();
 740   assert(current != NULL, "Thread::current() called on detached thread");
 741   return current;
 742 }
 743 
 744 inline Thread* Thread::current_or_null() {
 745 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 746   return _thr_current;
 747 #else
 748   if (ThreadLocalStorage::is_initialized()) {
 749     return ThreadLocalStorage::thread();
 750   }
 751   return NULL;
 752 #endif
 753 }
 754 
 755 inline Thread* Thread::current_or_null_safe() {
 756   if (ThreadLocalStorage::is_initialized()) {
 757     return ThreadLocalStorage::thread();
 758   }
 759   return NULL;
 760 }
 761 
 762 class NonJavaThread: public Thread {
 763   friend class VMStructs;
 764 
 765   NonJavaThread* volatile _next;
 766 
 767   class List;
 768   static List _the_list;
 769 
 770  public:
 771   NonJavaThread();
 772   ~NonJavaThread();
 773 
 774   class Iterator;
 775 };
 776 
 777 // Provides iteration over the list of NonJavaThreads.  Because list
 778 // management occurs in the NonJavaThread constructor and destructor,
 779 // entries in the list may not be fully constructed instances of a
 780 // derived class.  Threads created after an iterator is constructed
 781 // will not be visited by the iterator.  The scope of an iterator is a
 782 // critical section; there must be no safepoint checks in that scope.
 783 class NonJavaThread::Iterator : public StackObj {
 784   uint _protect_enter;
 785   NonJavaThread* _current;
 786 
 787   // Noncopyable.
 788   Iterator(const Iterator&);
 789   Iterator& operator=(const Iterator&);
 790 
 791 public:
 792   Iterator();
 793   ~Iterator();
 794 
 795   bool end() const { return _current == NULL; }
 796   NonJavaThread* current() const { return _current; }
 797   void step();
 798 };
 799 
 800 // Name support for threads.  non-JavaThread subclasses with multiple
 801 // uniquely named instances should derive from this.
 802 class NamedThread: public NonJavaThread {
 803   friend class VMStructs;
 804   enum {
 805     max_name_len = 64
 806   };
 807  private:
 808   char* _name;
 809   // log JavaThread being processed by oops_do
 810   JavaThread* _processed_thread;
 811   uint _gc_id; // The current GC id when a thread takes part in GC
 812 
 813  public:
 814   NamedThread();
 815   ~NamedThread();
 816   // May only be called once per thread.
 817   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 818   void initialize_named_thread();
 819   virtual bool is_Named_thread() const { return true; }
 820   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 821   JavaThread *processed_thread() { return _processed_thread; }
 822   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 823   virtual void print_on(outputStream* st) const;
 824 
 825   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 826   uint gc_id() { return _gc_id; }
 827 };
 828 
 829 // Worker threads are named and have an id of an assigned work.
 830 class WorkerThread: public NamedThread {
 831  private:
 832   uint _id;
 833  public:
 834   WorkerThread() : _id(0)               { }
 835   virtual bool is_Worker_thread() const { return true; }
 836 
 837   virtual WorkerThread* as_Worker_thread() const {
 838     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 839     return (WorkerThread*) this;
 840   }
 841 
 842   void set_id(uint work_id)             { _id = work_id; }
 843   uint id() const                       { return _id; }
 844 };
 845 
 846 // A single WatcherThread is used for simulating timer interrupts.
 847 class WatcherThread: public NonJavaThread {
 848   friend class VMStructs;
 849  public:
 850   virtual void run();
 851 
 852  private:
 853   static WatcherThread* _watcher_thread;
 854 
 855   static bool _startable;
 856   // volatile due to at least one lock-free read
 857   volatile static bool _should_terminate;
 858  public:
 859   enum SomeConstants {
 860     delay_interval = 10                          // interrupt delay in milliseconds
 861   };
 862 
 863   // Constructor
 864   WatcherThread();
 865 
 866   // No destruction allowed
 867   ~WatcherThread() {
 868     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 869   }
 870 
 871   // Tester
 872   bool is_Watcher_thread() const                 { return true; }
 873 
 874   // Printing
 875   char* name() const { return (char*)"VM Periodic Task Thread"; }
 876   void print_on(outputStream* st) const;
 877   void unpark();
 878 
 879   // Returns the single instance of WatcherThread
 880   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 881 
 882   // Create and start the single instance of WatcherThread, or stop it on shutdown
 883   static void start();
 884   static void stop();
 885   // Only allow start once the VM is sufficiently initialized
 886   // Otherwise the first task to enroll will trigger the start
 887   static void make_startable();
 888  private:
 889   int sleep() const;
 890 };
 891 
 892 
 893 class CompilerThread;
 894 
 895 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 896 
 897 class JavaThread: public Thread {
 898   friend class VMStructs;
 899   friend class JVMCIVMStructs;
 900   friend class WhiteBox;
 901  private:
 902   JavaThread*    _next;                          // The next thread in the Threads list
 903   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 904   oop            _threadObj;                     // The Java level thread object
 905 
 906 #ifdef ASSERT
 907  private:
 908   int _java_call_counter;
 909 
 910  public:
 911   int  java_call_counter()                       { return _java_call_counter; }
 912   void inc_java_call_counter()                   { _java_call_counter++; }
 913   void dec_java_call_counter() {
 914     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 915     _java_call_counter--;
 916   }
 917  private:  // restore original namespace restriction
 918 #endif  // ifdef ASSERT
 919 
 920 #ifndef PRODUCT
 921  public:
 922   enum {
 923     jump_ring_buffer_size = 16
 924   };
 925  private:  // restore original namespace restriction
 926 #endif
 927 
 928   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 929 
 930   ThreadFunction _entry_point;
 931 
 932   JNIEnv        _jni_environment;
 933 
 934   // Deopt support
 935   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 936 
 937   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 938                                                  // transition out of native
 939   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 940   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 941   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 942   // Because deoptimization is lazy we must save jvmti requests to set locals
 943   // in compiled frames until we deoptimize and we have an interpreter frame.
 944   // This holds the pointer to array (yeah like there might be more than one) of
 945   // description of compiled vframes that have locals that need to be updated.
 946   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 947 
 948   // Handshake value for fixing 6243940. We need a place for the i2c
 949   // adapter to store the callee Method*. This value is NEVER live
 950   // across a gc point so it does NOT have to be gc'd
 951   // The handshake is open ended since we can't be certain that it will
 952   // be NULLed. This is because we rarely ever see the race and end up
 953   // in handle_wrong_method which is the backend of the handshake. See
 954   // code in i2c adapters and handle_wrong_method.
 955 
 956   Method*       _callee_target;
 957 
 958   // Used to pass back results to the interpreter or generated code running Java code.
 959   oop           _vm_result;    // oop result is GC-preserved
 960   Metadata*     _vm_result_2;  // non-oop result
 961 
 962   // See ReduceInitialCardMarks: this holds the precise space interval of
 963   // the most recent slow path allocation for which compiled code has
 964   // elided card-marks for performance along the fast-path.
 965   MemRegion     _deferred_card_mark;
 966 
 967   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 968                                                  // allocated during deoptimization
 969                                                  // and by JNI_MonitorEnter/Exit
 970 
 971   // Async. requests support
 972   enum AsyncRequests {
 973     _no_async_condition = 0,
 974     _async_exception,
 975     _async_unsafe_access_error
 976   };
 977   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 978   oop           _pending_async_exception;
 979 
 980   // Safepoint support
 981  public:                                         // Expose _thread_state for SafeFetchInt()
 982   volatile JavaThreadState _thread_state;
 983  private:
 984   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 985   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 986 
 987   // JavaThread termination support
 988   enum TerminatedTypes {
 989     _not_terminated = 0xDEAD - 2,
 990     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 991     _thread_terminated,                          // JavaThread is removed from thread list
 992     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 993                                                  // only VM_Exit can set _vm_exited
 994   };
 995 
 996   // In general a JavaThread's _terminated field transitions as follows:
 997   //
 998   //   _not_terminated => _thread_exiting => _thread_terminated
 999   //
1000   // _vm_exited is a special value to cover the case of a JavaThread
1001   // executing native code after the VM itself is terminated.
1002   volatile TerminatedTypes _terminated;
1003   // suspend/resume support
1004   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1005   jint                  _in_deopt_handler;       // count of deoptimization
1006                                                  // handlers thread is in
1007   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1008   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1009                                                          // never locked) when throwing an exception. Used by interpreter only.
1010 
1011   // JNI attach states:
1012   enum JNIAttachStates {
1013     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1014     _attaching_via_jni,          // thread is attaching via JNI
1015     _attached_via_jni            // thread has attached via JNI
1016   };
1017 
1018   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1019   // A native thread that is attaching via JNI starts with a value
1020   // of _attaching_via_jni and transitions to _attached_via_jni.
1021   volatile JNIAttachStates _jni_attach_state;
1022 
1023  public:
1024   // State of the stack guard pages for this thread.
1025   enum StackGuardState {
1026     stack_guard_unused,         // not needed
1027     stack_guard_reserved_disabled,
1028     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1029     stack_guard_enabled         // enabled
1030   };
1031 
1032  private:
1033 
1034 #if INCLUDE_JVMCI
1035   // The _pending_* fields below are used to communicate extra information
1036   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1037 
1038   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1039   int       _pending_deoptimization;
1040 
1041   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1042   // before the monitor has been acquired.
1043   bool      _pending_monitorenter;
1044 
1045   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1046   bool      _pending_transfer_to_interpreter;
1047 
1048   // Guard for re-entrant call to JVMCIRuntime::adjust_comp_level
1049   bool      _adjusting_comp_level;
1050 
1051   // An id of a speculation that JVMCI compiled code can use to further describe and
1052   // uniquely identify the  speculative optimization guarded by the uncommon trap
1053   long       _pending_failed_speculation;
1054 
1055   // These fields are mutually exclusive in terms of live ranges.
1056   union {
1057     // Communicates the pc at which the most recent implicit exception occurred
1058     // from the signal handler to a deoptimization stub.
1059     address   _implicit_exception_pc;
1060 
1061     // Communicates an alternative call target to an i2c stub from a JavaCall .
1062     address   _alternate_call_target;
1063   } _jvmci;
1064 
1065   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1066   jlong*    _jvmci_counters;
1067 
1068  public:
1069   static jlong* _jvmci_old_thread_counters;
1070   static void collect_counters(typeArrayOop array);
1071  private:
1072 #endif // INCLUDE_JVMCI
1073 
1074   StackGuardState  _stack_guard_state;
1075 
1076   // Precompute the limit of the stack as used in stack overflow checks.
1077   // We load it from here to simplify the stack overflow check in assembly.
1078   address          _stack_overflow_limit;
1079   address          _reserved_stack_activation;
1080 
1081   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1082   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1083   // code)
1084   volatile oop     _exception_oop;               // Exception thrown in compiled code
1085   volatile address _exception_pc;                // PC where exception happened
1086   volatile address _exception_handler_pc;        // PC for handler of exception
1087   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1088 
1089  private:
1090   // support for JNI critical regions
1091   jint    _jni_active_critical;                  // count of entries into JNI critical region
1092 
1093   // Checked JNI: function name requires exception check
1094   char* _pending_jni_exception_check_fn;
1095 
1096   // For deadlock detection.
1097   int _depth_first_number;
1098 
1099   // JVMTI PopFrame support
1100   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1101   int _popframe_condition;
1102 
1103   // If reallocation of scalar replaced objects fails, we throw OOM
1104   // and during exception propagation, pop the top
1105   // _frames_to_pop_failed_realloc frames, the ones that reference
1106   // failed reallocations.
1107   int _frames_to_pop_failed_realloc;
1108 
1109 #ifndef PRODUCT
1110   int _jmp_ring_index;
1111   struct {
1112     // We use intptr_t instead of address so debugger doesn't try and display strings
1113     intptr_t _target;
1114     intptr_t _instruction;
1115     const char*  _file;
1116     int _line;
1117   }   _jmp_ring[jump_ring_buffer_size];
1118 #endif // PRODUCT
1119 
1120   friend class VMThread;
1121   friend class ThreadWaitTransition;
1122   friend class VM_Exit;
1123 
1124   void initialize();                             // Initialized the instance variables
1125 
1126  public:
1127   // Constructor
1128   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1129   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1130   ~JavaThread();
1131 
1132 #ifdef ASSERT
1133   // verify this JavaThread hasn't be published in the Threads::list yet
1134   void verify_not_published();
1135 #endif
1136 
1137   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1138   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1139     _jni_environment.functions = functionTable;
1140   }
1141   struct JNINativeInterface_* get_jni_functions() {
1142     return (struct JNINativeInterface_ *)_jni_environment.functions;
1143   }
1144 
1145   // This function is called at thread creation to allow
1146   // platform specific thread variables to be initialized.
1147   void cache_global_variables();
1148 
1149   // Executes Shutdown.shutdown()
1150   void invoke_shutdown_hooks();
1151 
1152   // Cleanup on thread exit
1153   enum ExitType {
1154     normal_exit,
1155     jni_detach
1156   };
1157   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1158 
1159   void cleanup_failed_attach_current_thread();
1160 
1161   // Testers
1162   virtual bool is_Java_thread() const            { return true;  }
1163   virtual bool can_call_java() const             { return true; }
1164 
1165   // Thread chain operations
1166   JavaThread* next() const                       { return _next; }
1167   void set_next(JavaThread* p)                   { _next = p; }
1168 
1169   // Thread oop. threadObj() can be NULL for initial JavaThread
1170   // (or for threads attached via JNI)
1171   oop threadObj() const                          { return _threadObj; }
1172   void set_threadObj(oop p)                      { _threadObj = p; }
1173 
1174   ThreadPriority java_priority() const;          // Read from threadObj()
1175 
1176   // Prepare thread and add to priority queue.  If a priority is
1177   // not specified, use the priority of the thread object. Threads_lock
1178   // must be held while this function is called.
1179   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1180 
1181   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1182   address saved_exception_pc()                   { return _saved_exception_pc; }
1183 
1184 
1185   ThreadFunction entry_point() const             { return _entry_point; }
1186 
1187   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1188   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1189 
1190   // Last frame anchor routines
1191 
1192   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1193 
1194   // last_Java_sp
1195   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1196   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1197 
1198   // last_Java_pc
1199 
1200   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1201 
1202   // Safepoint support
1203 #if !(defined(PPC64) || defined(AARCH64))
1204   JavaThreadState thread_state() const           { return _thread_state; }
1205   void set_thread_state(JavaThreadState s)       { _thread_state = s;    }
1206 #else
1207   // Use membars when accessing volatile _thread_state. See
1208   // Threads::create_vm() for size checks.
1209   inline JavaThreadState thread_state() const;
1210   inline void set_thread_state(JavaThreadState s);
1211 #endif
1212   ThreadSafepointState *safepoint_state() const  { return _safepoint_state; }
1213   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1214   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1215 
1216   // JavaThread termination and lifecycle support:
1217   void smr_delete();
1218   bool on_thread_list() const { return _on_thread_list; }
1219   void set_on_thread_list() { _on_thread_list = true; }
1220 
1221   // thread has called JavaThread::exit() or is terminated
1222   bool is_exiting() const;
1223   // thread is terminated (no longer on the threads list); we compare
1224   // against the two non-terminated values so that a freed JavaThread
1225   // will also be considered terminated.
1226   bool check_is_terminated(TerminatedTypes l_terminated) const {
1227     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1228   }
1229   bool is_terminated() const;
1230   void set_terminated(TerminatedTypes t);
1231   // special for Threads::remove() which is static:
1232   void set_terminated_value();
1233   void block_if_vm_exited();
1234 
1235   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1236   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1237 
1238   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1239   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1240 
1241   inline void set_polling_page_release(void* poll_value);
1242   inline void set_polling_page(void* poll_value);
1243   inline volatile void* get_polling_page();
1244 
1245  private:
1246   // Support for thread handshake operations
1247   HandshakeState _handshake;
1248  public:
1249   void set_handshake_operation(HandshakeOperation* op) {
1250     _handshake.set_operation(this, op);
1251   }
1252 
1253   bool has_handshake() const {
1254     return _handshake.has_operation();
1255   }
1256 
1257   void cancel_handshake() {
1258     _handshake.cancel(this);
1259   }
1260 
1261   void handshake_process_by_self() {
1262     _handshake.process_by_self(this);
1263   }
1264 
1265   void handshake_process_by_vmthread() {
1266     _handshake.process_by_vmthread(this);
1267   }
1268 
1269   // Suspend/resume support for JavaThread
1270  private:
1271   inline void set_ext_suspended();
1272   inline void clear_ext_suspended();
1273 
1274  public:
1275   void java_suspend();
1276   void java_resume();
1277   int  java_suspend_self();
1278 
1279   void check_and_wait_while_suspended() {
1280     assert(JavaThread::current() == this, "sanity check");
1281 
1282     bool do_self_suspend;
1283     do {
1284       // were we externally suspended while we were waiting?
1285       do_self_suspend = handle_special_suspend_equivalent_condition();
1286       if (do_self_suspend) {
1287         // don't surprise the thread that suspended us by returning
1288         java_suspend_self();
1289         set_suspend_equivalent();
1290       }
1291     } while (do_self_suspend);
1292   }
1293   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1294   // Check for async exception in addition to safepoint and suspend request.
1295   static void check_special_condition_for_native_trans(JavaThread *thread);
1296 
1297   // Same as check_special_condition_for_native_trans but finishes the
1298   // transition into thread_in_Java mode so that it can potentially
1299   // block.
1300   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1301 
1302   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1303   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1304     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1305     // Warning: is_ext_suspend_completed() may temporarily drop the
1306     // SR_lock to allow the thread to reach a stable thread state if
1307     // it is currently in a transient thread state.
1308     return is_ext_suspend_completed(false /* !called_by_wait */,
1309                                     SuspendRetryDelay, bits);
1310   }
1311 
1312   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1313   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1314   // passed as the count and delay parameters. Experiments with specific
1315   // calls to wait_for_ext_suspend_completion() can be done by passing
1316   // other values in the code. Experiments with all calls can be done
1317   // via the appropriate -XX options.
1318   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1319 
1320   // test for suspend - most (all?) of these should go away
1321   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1322 
1323   inline void set_external_suspend();
1324   inline void clear_external_suspend();
1325 
1326   inline void set_deopt_suspend();
1327   inline void clear_deopt_suspend();
1328   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1329 
1330   bool is_external_suspend() const {
1331     return (_suspend_flags & _external_suspend) != 0;
1332   }
1333   // Whenever a thread transitions from native to vm/java it must suspend
1334   // if external|deopt suspend is present.
1335   bool is_suspend_after_native() const {
1336     return (_suspend_flags & (_external_suspend | _deopt_suspend)) != 0;
1337   }
1338 
1339   // external suspend request is completed
1340   bool is_ext_suspended() const {
1341     return (_suspend_flags & _ext_suspended) != 0;
1342   }
1343 
1344   bool is_external_suspend_with_lock() const {
1345     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1346     return is_external_suspend();
1347   }
1348 
1349   // Special method to handle a pending external suspend request
1350   // when a suspend equivalent condition lifts.
1351   bool handle_special_suspend_equivalent_condition() {
1352     assert(is_suspend_equivalent(),
1353            "should only be called in a suspend equivalence condition");
1354     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1355     bool ret = is_external_suspend();
1356     if (!ret) {
1357       // not about to self-suspend so clear suspend equivalence
1358       clear_suspend_equivalent();
1359     }
1360     // implied else:
1361     // We have a pending external suspend request so we leave the
1362     // suspend_equivalent flag set until java_suspend_self() sets
1363     // the ext_suspended flag and clears the suspend_equivalent
1364     // flag. This insures that wait_for_ext_suspend_completion()
1365     // will return consistent values.
1366     return ret;
1367   }
1368 
1369   // utility methods to see if we are doing some kind of suspension
1370   bool is_being_ext_suspended() const            {
1371     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1372     return is_ext_suspended() || is_external_suspend();
1373   }
1374 
1375   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1376 
1377   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1378   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1379 
1380   // Thread.stop support
1381   void send_thread_stop(oop throwable);
1382   AsyncRequests clear_special_runtime_exit_condition() {
1383     AsyncRequests x = _special_runtime_exit_condition;
1384     _special_runtime_exit_condition = _no_async_condition;
1385     return x;
1386   }
1387 
1388   // Are any async conditions present?
1389   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1390 
1391   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1392 
1393   // these next two are also used for self-suspension and async exception support
1394   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1395 
1396   // Return true if JavaThread has an asynchronous condition or
1397   // if external suspension is requested.
1398   bool has_special_runtime_exit_condition() {
1399     // Because we don't use is_external_suspend_with_lock
1400     // it is possible that we won't see an asynchronous external suspend
1401     // request that has just gotten started, i.e., SR_lock grabbed but
1402     // _external_suspend field change either not made yet or not visible
1403     // yet. However, this is okay because the request is asynchronous and
1404     // we will see the new flag value the next time through. It's also
1405     // possible that the external suspend request is dropped after
1406     // we have checked is_external_suspend(), we will recheck its value
1407     // under SR_lock in java_suspend_self().
1408     return (_special_runtime_exit_condition != _no_async_condition) ||
1409             is_external_suspend() || is_trace_suspend();
1410   }
1411 
1412   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1413 
1414   inline void set_pending_async_exception(oop e);
1415 
1416   // Fast-locking support
1417   bool is_lock_owned(address adr) const;
1418 
1419   // Accessors for vframe array top
1420   // The linked list of vframe arrays are sorted on sp. This means when we
1421   // unpack the head must contain the vframe array to unpack.
1422   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1423   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1424 
1425   // Side structure for deferring update of java frame locals until deopt occurs
1426   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1427   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1428 
1429   // These only really exist to make debugging deopt problems simpler
1430 
1431   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1432   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1433 
1434   // The special resourceMark used during deoptimization
1435 
1436   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1437   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1438 
1439   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1440   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1441   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1442 
1443   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1444   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1445 
1446   Method*    callee_target() const               { return _callee_target; }
1447   void set_callee_target  (Method* x)          { _callee_target   = x; }
1448 
1449   // Oop results of vm runtime calls
1450   oop  vm_result() const                         { return _vm_result; }
1451   void set_vm_result  (oop x)                    { _vm_result   = x; }
1452 
1453   Metadata*    vm_result_2() const               { return _vm_result_2; }
1454   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1455 
1456   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1457   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1458 
1459 #if INCLUDE_JVMCI
1460   int  pending_deoptimization() const             { return _pending_deoptimization; }
1461   long  pending_failed_speculation() const         { return _pending_failed_speculation; }
1462   bool adjusting_comp_level() const               { return _adjusting_comp_level; }
1463   void set_adjusting_comp_level(bool b)           { _adjusting_comp_level = b; }
1464   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1465   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1466   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1467   void set_pending_failed_speculation(long failed_speculation) { _pending_failed_speculation = failed_speculation; }
1468   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1469   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1470   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1471 #endif // INCLUDE_JVMCI
1472 
1473   // Exception handling for compiled methods
1474   oop      exception_oop() const                 { return _exception_oop; }
1475   address  exception_pc() const                  { return _exception_pc; }
1476   address  exception_handler_pc() const          { return _exception_handler_pc; }
1477   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1478 
1479   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1480   void set_exception_pc(address a)               { _exception_pc = a; }
1481   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1482   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1483 
1484   void clear_exception_oop_and_pc() {
1485     set_exception_oop(NULL);
1486     set_exception_pc(NULL);
1487   }
1488 
1489   // Stack overflow support
1490   //
1491   //  (small addresses)
1492   //
1493   //  --  <-- stack_end()                   ---
1494   //  |                                      |
1495   //  |  red pages                           |
1496   //  |                                      |
1497   //  --  <-- stack_red_zone_base()          |
1498   //  |                                      |
1499   //  |                                     guard
1500   //  |  yellow pages                       zone
1501   //  |                                      |
1502   //  |                                      |
1503   //  --  <-- stack_yellow_zone_base()       |
1504   //  |                                      |
1505   //  |                                      |
1506   //  |  reserved pages                      |
1507   //  |                                      |
1508   //  --  <-- stack_reserved_zone_base()    ---      ---
1509   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1510   //                                                  |   zone
1511   //                                                 \|/  size
1512   //  some untouched memory                          ---
1513   //
1514   //
1515   //  --
1516   //  |
1517   //  |  shadow zone
1518   //  |
1519   //  --
1520   //  x    frame n
1521   //  --
1522   //  x    frame n-1
1523   //  x
1524   //  --
1525   //  ...
1526   //
1527   //  --
1528   //  x    frame 0
1529   //  --  <-- stack_base()
1530   //
1531   //  (large addresses)
1532   //
1533 
1534  private:
1535   // These values are derived from flags StackRedPages, StackYellowPages,
1536   // StackReservedPages and StackShadowPages. The zone size is determined
1537   // ergonomically if page_size > 4K.
1538   static size_t _stack_red_zone_size;
1539   static size_t _stack_yellow_zone_size;
1540   static size_t _stack_reserved_zone_size;
1541   static size_t _stack_shadow_zone_size;
1542  public:
1543   inline size_t stack_available(address cur_sp);
1544 
1545   static size_t stack_red_zone_size() {
1546     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1547     return _stack_red_zone_size;
1548   }
1549   static void set_stack_red_zone_size(size_t s) {
1550     assert(is_aligned(s, os::vm_page_size()),
1551            "We can not protect if the red zone size is not page aligned.");
1552     assert(_stack_red_zone_size == 0, "This should be called only once.");
1553     _stack_red_zone_size = s;
1554   }
1555   address stack_red_zone_base() {
1556     return (address)(stack_end() + stack_red_zone_size());
1557   }
1558   bool in_stack_red_zone(address a) {
1559     return a <= stack_red_zone_base() && a >= stack_end();
1560   }
1561 
1562   static size_t stack_yellow_zone_size() {
1563     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1564     return _stack_yellow_zone_size;
1565   }
1566   static void set_stack_yellow_zone_size(size_t s) {
1567     assert(is_aligned(s, os::vm_page_size()),
1568            "We can not protect if the yellow zone size is not page aligned.");
1569     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1570     _stack_yellow_zone_size = s;
1571   }
1572 
1573   static size_t stack_reserved_zone_size() {
1574     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1575     return _stack_reserved_zone_size;
1576   }
1577   static void set_stack_reserved_zone_size(size_t s) {
1578     assert(is_aligned(s, os::vm_page_size()),
1579            "We can not protect if the reserved zone size is not page aligned.");
1580     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1581     _stack_reserved_zone_size = s;
1582   }
1583   address stack_reserved_zone_base() {
1584     return (address)(stack_end() +
1585                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1586   }
1587   bool in_stack_reserved_zone(address a) {
1588     return (a <= stack_reserved_zone_base()) &&
1589            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1590   }
1591 
1592   static size_t stack_yellow_reserved_zone_size() {
1593     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1594   }
1595   bool in_stack_yellow_reserved_zone(address a) {
1596     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1597   }
1598 
1599   // Size of red + yellow + reserved zones.
1600   static size_t stack_guard_zone_size() {
1601     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1602   }
1603 
1604   static size_t stack_shadow_zone_size() {
1605     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1606     return _stack_shadow_zone_size;
1607   }
1608   static void set_stack_shadow_zone_size(size_t s) {
1609     // The shadow area is not allocated or protected, so
1610     // it needs not be page aligned.
1611     // But the stack bang currently assumes that it is a
1612     // multiple of page size. This guarantees that the bang
1613     // loop touches all pages in the shadow zone.
1614     // This can be guaranteed differently, as well.  E.g., if
1615     // the page size is a multiple of 4K, banging in 4K steps
1616     // suffices to touch all pages. (Some pages are banged
1617     // several times, though.)
1618     assert(is_aligned(s, os::vm_page_size()),
1619            "Stack bang assumes multiple of page size.");
1620     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1621     _stack_shadow_zone_size = s;
1622   }
1623 
1624   void create_stack_guard_pages();
1625   void remove_stack_guard_pages();
1626 
1627   void enable_stack_reserved_zone();
1628   void disable_stack_reserved_zone();
1629   void enable_stack_yellow_reserved_zone();
1630   void disable_stack_yellow_reserved_zone();
1631   void enable_stack_red_zone();
1632   void disable_stack_red_zone();
1633 
1634   inline bool stack_guard_zone_unused();
1635   inline bool stack_yellow_reserved_zone_disabled();
1636   inline bool stack_reserved_zone_disabled();
1637   inline bool stack_guards_enabled();
1638 
1639   address reserved_stack_activation() const { return _reserved_stack_activation; }
1640   void set_reserved_stack_activation(address addr) {
1641     assert(_reserved_stack_activation == stack_base()
1642             || _reserved_stack_activation == NULL
1643             || addr == stack_base(), "Must not be set twice");
1644     _reserved_stack_activation = addr;
1645   }
1646 
1647   // Attempt to reguard the stack after a stack overflow may have occurred.
1648   // Returns true if (a) guard pages are not needed on this thread, (b) the
1649   // pages are already guarded, or (c) the pages were successfully reguarded.
1650   // Returns false if there is not enough stack space to reguard the pages, in
1651   // which case the caller should unwind a frame and try again.  The argument
1652   // should be the caller's (approximate) sp.
1653   bool reguard_stack(address cur_sp);
1654   // Similar to above but see if current stackpoint is out of the guard area
1655   // and reguard if possible.
1656   bool reguard_stack(void);
1657 
1658   address stack_overflow_limit() { return _stack_overflow_limit; }
1659   void set_stack_overflow_limit() {
1660     _stack_overflow_limit =
1661       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1662   }
1663 
1664   // Misc. accessors/mutators
1665   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1666   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1667   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1668 
1669 #ifndef PRODUCT
1670   void record_jump(address target, address instr, const char* file, int line);
1671 #endif // PRODUCT
1672 
1673   // For assembly stub generation
1674   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1675 #ifndef PRODUCT
1676   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1677   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1678 #endif // PRODUCT
1679   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1680   static ByteSize pending_jni_exception_check_fn_offset() {
1681     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1682   }
1683   static ByteSize last_Java_sp_offset() {
1684     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1685   }
1686   static ByteSize last_Java_pc_offset() {
1687     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1688   }
1689   static ByteSize frame_anchor_offset() {
1690     return byte_offset_of(JavaThread, _anchor);
1691   }
1692   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1693   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1694   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1695   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1696   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1697   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1698 #if INCLUDE_JVMCI
1699   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1700   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1701   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1702   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1703   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1704   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1705 #endif // INCLUDE_JVMCI
1706   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1707   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1708   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1709   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1710   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1711   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1712   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1713   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1714 
1715   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1716   static ByteSize should_post_on_exceptions_flag_offset() {
1717     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1718   }
1719 
1720   // Returns the jni environment for this thread
1721   JNIEnv* jni_environment()                      { return &_jni_environment; }
1722 
1723   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1724     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1725     // Only return NULL if thread is off the thread list; starting to
1726     // exit should not return NULL.
1727     if (thread_from_jni_env->is_terminated()) {
1728       thread_from_jni_env->block_if_vm_exited();
1729       return NULL;
1730     } else {
1731       return thread_from_jni_env;
1732     }
1733   }
1734 
1735   // JNI critical regions. These can nest.
1736   bool in_critical()    { return _jni_active_critical > 0; }
1737   bool in_last_critical()  { return _jni_active_critical == 1; }
1738   void enter_critical() {
1739     assert(Thread::current() == this ||
1740            (Thread::current()->is_VM_thread() &&
1741            SafepointSynchronize::is_synchronizing()),
1742            "this must be current thread or synchronizing");
1743     _jni_active_critical++;
1744   }
1745   void exit_critical() {
1746     assert(Thread::current() == this, "this must be current thread");
1747     _jni_active_critical--;
1748     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1749   }
1750 
1751   // Checked JNI: is the programmer required to check for exceptions, if so specify
1752   // which function name. Returning to a Java frame should implicitly clear the
1753   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1754   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1755   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1756   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1757   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1758   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1759   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1760 
1761   // For deadlock detection
1762   int depth_first_number() { return _depth_first_number; }
1763   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1764 
1765  private:
1766   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1767 
1768  public:
1769   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1770   void add_monitor_chunk(MonitorChunk* chunk);
1771   void remove_monitor_chunk(MonitorChunk* chunk);
1772   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1773   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1774   void dec_in_deopt_handler() {
1775     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1776     if (_in_deopt_handler > 0) { // robustness
1777       _in_deopt_handler--;
1778     }
1779   }
1780 
1781  private:
1782   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1783 
1784  public:
1785 
1786   // Frame iteration; calls the function f for all frames on the stack
1787   void frames_do(void f(frame*, const RegisterMap*));
1788 
1789   // Memory operations
1790   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1791 
1792   // Sweeper operations
1793   virtual void nmethods_do(CodeBlobClosure* cf);
1794 
1795   // RedefineClasses Support
1796   void metadata_do(void f(Metadata*));
1797 
1798   // Misc. operations
1799   char* name() const { return (char*)get_thread_name(); }
1800   void print_on(outputStream* st, bool print_extended_info) const;
1801   void print_on(outputStream* st) const { print_on(st, false); }
1802   void print_value();
1803   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1804   void print_thread_state() const                      PRODUCT_RETURN;
1805   void print_on_error(outputStream* st, char* buf, int buflen) const;
1806   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1807   void verify();
1808   const char* get_thread_name() const;
1809  private:
1810   // factor out low-level mechanics for use in both normal and error cases
1811   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1812  public:
1813   const char* get_threadgroup_name() const;
1814   const char* get_parent_name() const;
1815 
1816   // Accessing frames
1817   frame last_frame() {
1818     _anchor.make_walkable(this);
1819     return pd_last_frame();
1820   }
1821   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1822 
1823   // Returns method at 'depth' java or native frames down the stack
1824   // Used for security checks
1825   Klass* security_get_caller_class(int depth);
1826 
1827   // Print stack trace in external format
1828   void print_stack_on(outputStream* st);
1829   void print_stack() { print_stack_on(tty); }
1830 
1831   // Print stack traces in various internal formats
1832   void trace_stack()                             PRODUCT_RETURN;
1833   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1834   void trace_frames()                            PRODUCT_RETURN;
1835   void trace_oops()                              PRODUCT_RETURN;
1836 
1837   // Print an annotated view of the stack frames
1838   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1839   void validate_frame_layout() {
1840     print_frame_layout(0, true);
1841   }
1842 
1843   // Returns the number of stack frames on the stack
1844   int depth() const;
1845 
1846   // Function for testing deoptimization
1847   void deoptimize();
1848   void make_zombies();
1849 
1850   void deoptimized_wrt_marked_nmethods();
1851 
1852  public:
1853   // Returns the running thread as a JavaThread
1854   static inline JavaThread* current();
1855 
1856   // Returns the active Java thread.  Do not use this if you know you are calling
1857   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1858   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1859   // operation.  You may not want that either.
1860   static JavaThread* active();
1861 
1862   inline CompilerThread* as_CompilerThread();
1863 
1864  public:
1865   virtual void run();
1866   void thread_main_inner();
1867 
1868  private:
1869   // PRIVILEGED STACK
1870   PrivilegedElement*  _privileged_stack_top;
1871   GrowableArray<oop>* _array_for_gc;
1872  public:
1873 
1874   // Returns the privileged_stack information.
1875   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1876   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1877   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1878 
1879  public:
1880   // Thread local information maintained by JVMTI.
1881   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1882   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1883   // getter is used to get this JavaThread's JvmtiThreadState if it has
1884   // one which means NULL can be returned. JvmtiThreadState::state_for()
1885   // is used to get the specified JavaThread's JvmtiThreadState if it has
1886   // one or it allocates a new JvmtiThreadState for the JavaThread and
1887   // returns it. JvmtiThreadState::state_for() will return NULL only if
1888   // the specified JavaThread is exiting.
1889   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1890   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1891 
1892   // JVMTI PopFrame support
1893   // Setting and clearing popframe_condition
1894   // All of these enumerated values are bits. popframe_pending
1895   // indicates that a PopFrame() has been requested and not yet been
1896   // completed. popframe_processing indicates that that PopFrame() is in
1897   // the process of being completed. popframe_force_deopt_reexecution_bit
1898   // indicates that special handling is required when returning to a
1899   // deoptimized caller.
1900   enum PopCondition {
1901     popframe_inactive                      = 0x00,
1902     popframe_pending_bit                   = 0x01,
1903     popframe_processing_bit                = 0x02,
1904     popframe_force_deopt_reexecution_bit   = 0x04
1905   };
1906   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1907   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1908   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1909   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1910   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1911   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1912   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1913   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1914 #ifdef CC_INTERP
1915   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1916   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1917   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1918   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1919   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1920 #endif
1921 
1922   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1923   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1924   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1925 
1926  private:
1927   // Saved incoming arguments to popped frame.
1928   // Used only when popped interpreted frame returns to deoptimized frame.
1929   void*    _popframe_preserved_args;
1930   int      _popframe_preserved_args_size;
1931 
1932  public:
1933   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1934   void* popframe_preserved_args();
1935   ByteSize popframe_preserved_args_size();
1936   WordSize popframe_preserved_args_size_in_words();
1937   void  popframe_free_preserved_args();
1938 
1939 
1940  private:
1941   JvmtiThreadState *_jvmti_thread_state;
1942 
1943   // Used by the interpreter in fullspeed mode for frame pop, method
1944   // entry, method exit and single stepping support. This field is
1945   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1946   // It can be set to zero asynchronously (i.e., without a VM operation
1947   // or a lock) so we have to be very careful.
1948   int               _interp_only_mode;
1949 
1950  public:
1951   // used by the interpreter for fullspeed debugging support (see above)
1952   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1953   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1954   int get_interp_only_mode()                { return _interp_only_mode; }
1955   void increment_interp_only_mode()         { ++_interp_only_mode; }
1956   void decrement_interp_only_mode()         { --_interp_only_mode; }
1957 
1958   // support for cached flag that indicates whether exceptions need to be posted for this thread
1959   // if this is false, we can avoid deoptimizing when events are thrown
1960   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1961  private:
1962   int    _should_post_on_exceptions_flag;
1963 
1964  public:
1965   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1966   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1967 
1968  private:
1969   ThreadStatistics *_thread_stat;
1970 
1971  public:
1972   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1973 
1974   // Return a blocker object for which this thread is blocked parking.
1975   oop current_park_blocker();
1976 
1977  private:
1978   static size_t _stack_size_at_create;
1979 
1980  public:
1981   static inline size_t stack_size_at_create(void) {
1982     return _stack_size_at_create;
1983   }
1984   static inline void set_stack_size_at_create(size_t value) {
1985     _stack_size_at_create = value;
1986   }
1987 
1988   // Machine dependent stuff
1989 #include OS_CPU_HEADER(thread)
1990 
1991  public:
1992   void set_blocked_on_compilation(bool value) {
1993     _blocked_on_compilation = value;
1994   }
1995 
1996   bool blocked_on_compilation() {
1997     return _blocked_on_compilation;
1998   }
1999  protected:
2000   bool         _blocked_on_compilation;
2001 
2002 
2003   // JSR166 per-thread parker
2004  private:
2005   Parker*    _parker;
2006  public:
2007   Parker*     parker() { return _parker; }
2008 
2009   // Biased locking support
2010  private:
2011   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2012  public:
2013   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2014   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2015 
2016   // clearing/querying jni attach status
2017   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2018   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2019   inline void set_done_attaching_via_jni();
2020 };
2021 
2022 // Inline implementation of JavaThread::current
2023 inline JavaThread* JavaThread::current() {
2024   Thread* thread = Thread::current();
2025   assert(thread->is_Java_thread(), "just checking");
2026   return (JavaThread*)thread;
2027 }
2028 
2029 inline CompilerThread* JavaThread::as_CompilerThread() {
2030   assert(is_Compiler_thread(), "just checking");
2031   return (CompilerThread*)this;
2032 }
2033 
2034 // Dedicated thread to sweep the code cache
2035 class CodeCacheSweeperThread : public JavaThread {
2036   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2037  public:
2038   CodeCacheSweeperThread();
2039   // Track the nmethod currently being scanned by the sweeper
2040   void set_scanned_compiled_method(CompiledMethod* cm) {
2041     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2042     _scanned_compiled_method = cm;
2043   }
2044 
2045   // Hide sweeper thread from external view.
2046   bool is_hidden_from_external_view() const { return true; }
2047 
2048   bool is_Code_cache_sweeper_thread() const { return true; }
2049 
2050   // Prevent GC from unloading _scanned_compiled_method
2051   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2052   void nmethods_do(CodeBlobClosure* cf);
2053 };
2054 
2055 // A thread used for Compilation.
2056 class CompilerThread : public JavaThread {
2057   friend class VMStructs;
2058  private:
2059   CompilerCounters* _counters;
2060 
2061   ciEnv*                _env;
2062   CompileLog*           _log;
2063   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2064   CompileQueue*         _queue;
2065   BufferBlob*           _buffer_blob;
2066 
2067   AbstractCompiler*     _compiler;
2068   TimeStamp             _idle_time;
2069 
2070  public:
2071 
2072   static CompilerThread* current();
2073 
2074   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2075   ~CompilerThread();
2076 
2077   bool is_Compiler_thread() const                { return true; }
2078 
2079   virtual bool can_call_java() const;
2080 
2081   // Hide native compiler threads from external view.
2082   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2083 
2084   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2085   AbstractCompiler* compiler() const             { return _compiler; }
2086 
2087   CompileQueue* queue()        const             { return _queue; }
2088   CompilerCounters* counters() const             { return _counters; }
2089 
2090   // Get/set the thread's compilation environment.
2091   ciEnv*        env()                            { return _env; }
2092   void          set_env(ciEnv* env)              { _env = env; }
2093 
2094   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2095   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2096 
2097   // Get/set the thread's logging information
2098   CompileLog*   log()                            { return _log; }
2099   void          init_log(CompileLog* log) {
2100     // Set once, for good.
2101     assert(_log == NULL, "set only once");
2102     _log = log;
2103   }
2104 
2105   void start_idle_timer()                        { _idle_time.update(); }
2106   jlong idle_time_millis() {
2107     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2108   }
2109 
2110 #ifndef PRODUCT
2111  private:
2112   IdealGraphPrinter *_ideal_graph_printer;
2113  public:
2114   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2115   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2116 #endif
2117 
2118   // Get/set the thread's current task
2119   CompileTask* task()                      { return _task; }
2120   void         set_task(CompileTask* task) { _task = task; }
2121 };
2122 
2123 inline CompilerThread* CompilerThread::current() {
2124   return JavaThread::current()->as_CompilerThread();
2125 }
2126 
2127 // The active thread queue. It also keeps track of the current used
2128 // thread priorities.
2129 class Threads: AllStatic {
2130   friend class VMStructs;
2131  private:
2132   static JavaThread* _thread_list;
2133   static int         _number_of_threads;
2134   static int         _number_of_non_daemon_threads;
2135   static int         _return_code;
2136   static int         _thread_claim_parity;
2137 #ifdef ASSERT
2138   static bool        _vm_complete;
2139   static size_t      _threads_before_barrier_set;
2140 #endif
2141 
2142   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2143   static void initialize_jsr292_core_classes(TRAPS);
2144 
2145  public:
2146   // Thread management
2147   // force_daemon is a concession to JNI, where we may need to add a
2148   // thread to the thread list before allocating its thread object
2149   static void add(JavaThread* p, bool force_daemon = false);
2150   static void remove(JavaThread* p);
2151   static void non_java_threads_do(ThreadClosure* tc);
2152   static void java_threads_do(ThreadClosure* tc);
2153   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2154   static void threads_do(ThreadClosure* tc);
2155   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2156 
2157   // Initializes the vm and creates the vm thread
2158   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2159   static void convert_vm_init_libraries_to_agents();
2160   static void create_vm_init_libraries();
2161   static void create_vm_init_agents();
2162   static void shutdown_vm_agents();
2163   static bool destroy_vm();
2164   // Supported VM versions via JNI
2165   // Includes JNI_VERSION_1_1
2166   static jboolean is_supported_jni_version_including_1_1(jint version);
2167   // Does not include JNI_VERSION_1_1
2168   static jboolean is_supported_jni_version(jint version);
2169 
2170   // The "thread claim parity" provides a way for threads to be claimed
2171   // by parallel worker tasks.
2172   //
2173   // Each thread contains a a "parity" field. A task will claim the
2174   // thread only if its parity field is the same as the global parity,
2175   // which is updated by calling change_thread_claim_parity().
2176   //
2177   // For this to work change_thread_claim_parity() needs to be called
2178   // exactly once in sequential code before starting parallel tasks
2179   // that should claim threads.
2180   //
2181   // New threads get their parity set to 0 and change_thread_claim_parity()
2182   // never set the global parity to 0.
2183   static int thread_claim_parity() { return _thread_claim_parity; }
2184   static void change_thread_claim_parity();
2185   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2186 
2187   // Apply "f->do_oop" to all root oops in all threads.
2188   // This version may only be called by sequential code.
2189   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2190   // This version may be called by sequential or parallel code.
2191   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2192 
2193   // Apply "f->do_oop" to roots in all threads that
2194   // are part of compiled frames
2195   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2196 
2197   static void convert_hcode_pointers();
2198   static void restore_hcode_pointers();
2199 
2200   // Sweeper
2201   static void nmethods_do(CodeBlobClosure* cf);
2202 
2203   // RedefineClasses support
2204   static void metadata_do(void f(Metadata*));
2205   static void metadata_handles_do(void f(Metadata*));
2206 
2207 #ifdef ASSERT
2208   static bool is_vm_complete() { return _vm_complete; }
2209 
2210   static size_t threads_before_barrier_set() {
2211     return _threads_before_barrier_set;
2212   }
2213 
2214   static void inc_threads_before_barrier_set() {
2215     ++_threads_before_barrier_set;
2216   }
2217 #endif // ASSERT
2218 
2219   // Verification
2220   static void verify();
2221   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2222   static void print(bool print_stacks, bool internal_format) {
2223     // this function is only used by debug.cpp
2224     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2225   }
2226   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2227   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2228                              int buflen, bool* found_current);
2229   static void print_threads_compiling(outputStream* st, char* buf, int buflen);
2230 
2231   // Get Java threads that are waiting to enter a monitor.
2232   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2233                                                          int count, address monitor);
2234 
2235   // Get owning Java thread from the monitor's owner field.
2236   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2237                                                       address owner);
2238 
2239   // Number of threads on the active threads list
2240   static int number_of_threads()                 { return _number_of_threads; }
2241   // Number of non-daemon threads on the active threads list
2242   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2243 
2244   // Deoptimizes all frames tied to marked nmethods
2245   static void deoptimized_wrt_marked_nmethods();
2246 };
2247 
2248 
2249 // Thread iterator
2250 class ThreadClosure: public StackObj {
2251  public:
2252   virtual void do_thread(Thread* thread) = 0;
2253 };
2254 
2255 class SignalHandlerMark: public StackObj {
2256  private:
2257   Thread* _thread;
2258  public:
2259   SignalHandlerMark(Thread* t) {
2260     _thread = t;
2261     if (_thread) _thread->enter_signal_handler();
2262   }
2263   ~SignalHandlerMark() {
2264     if (_thread) _thread->leave_signal_handler();
2265     _thread = NULL;
2266   }
2267 };
2268 
2269 
2270 #endif // SHARE_VM_RUNTIME_THREAD_HPP