rev 50392 : JEP 331

   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/threadLocalStorage.hpp"
  46 #include "runtime/unhandledOops.hpp"
  47 #include "utilities/align.hpp"
  48 #include "utilities/exceptions.hpp"
  49 #include "utilities/macros.hpp"
  50 #ifdef ZERO
  51 # include "stack_zero.hpp"
  52 #endif
  53 #if INCLUDE_JFR
  54 #include "jfr/support/jfrThreadExtension.hpp"
  55 #endif
  56 
  57 
  58 class SafeThreadsListPtr;
  59 class ThreadSafepointState;
  60 class ThreadsList;
  61 class ThreadsSMRSupport;
  62 
  63 class JvmtiThreadState;
  64 class JvmtiGetLoadedClassesClosure;
  65 class ThreadStatistics;
  66 class ConcurrentLocksDump;
  67 class ParkEvent;
  68 class Parker;
  69 
  70 class ciEnv;
  71 class CompileThread;
  72 class CompileLog;
  73 class CompileTask;
  74 class CompileQueue;
  75 class CompilerCounters;
  76 class vframeArray;
  77 
  78 class DeoptResourceMark;
  79 class jvmtiDeferredLocalVariableSet;
  80 
  81 class GCTaskQueue;
  82 class ThreadClosure;
  83 class IdealGraphPrinter;
  84 
  85 class Metadata;
  86 template <class T, MEMFLAGS F> class ChunkedList;
  87 typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;
  88 
  89 DEBUG_ONLY(class ResourceMark;)
  90 
  91 class WorkerThread;
  92 
  93 // Class hierarchy
  94 // - Thread
  95 //   - NamedThread
  96 //     - VMThread
  97 //     - ConcurrentGCThread
  98 //     - WorkerThread
  99 //       - GangWorker
 100 //       - GCTaskThread
 101 //   - JavaThread
 102 //     - various subclasses eg CompilerThread, ServiceThread
 103 //   - WatcherThread
 104 
 105 class Thread: public ThreadShadow {
 106   friend class VMStructs;
 107   friend class JVMCIVMStructs;
 108  private:
 109 
 110 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 111   // Current thread is maintained as a thread-local variable
 112   static THREAD_LOCAL_DECL Thread* _thr_current;
 113 #endif
 114 
 115  private:
 116   // Thread local data area available to the GC. The internal
 117   // structure and contents of this data area is GC-specific.
 118   // Only GC and GC barrier code should access this data area.
 119   GCThreadLocalData _gc_data;
 120 
 121  public:
 122   static ByteSize gc_data_offset() {
 123     return byte_offset_of(Thread, _gc_data);
 124   }
 125 
 126   template <typename T> T* gc_data() {
 127     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 128     return reinterpret_cast<T*>(&_gc_data);
 129   }
 130 
 131   // Exception handling
 132   // (Note: _pending_exception and friends are in ThreadShadow)
 133   //oop       _pending_exception;                // pending exception for current thread
 134   // const char* _exception_file;                   // file information for exception (debugging only)
 135   // int         _exception_line;                   // line information for exception (debugging only)
 136  protected:
 137   // Support for forcing alignment of thread objects for biased locking
 138   void*       _real_malloc_address;
 139 
 140   // JavaThread lifecycle support:
 141   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
 142   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 143   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 144   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 145   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 146 
 147   ThreadsList* volatile _threads_hazard_ptr;
 148   SafeThreadsListPtr*   _threads_list_ptr;
 149   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 150   ThreadsList*          get_threads_hazard_ptr();
 151   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 152   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 153     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 154   }
 155   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 156     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 157   }
 158   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 159     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 160   }
 161   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 162   uint _nested_threads_hazard_ptr_cnt;
 163   void dec_nested_threads_hazard_ptr_cnt() {
 164     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 165     _nested_threads_hazard_ptr_cnt--;
 166   }
 167   void inc_nested_threads_hazard_ptr_cnt() {
 168     _nested_threads_hazard_ptr_cnt++;
 169   }
 170   uint nested_threads_hazard_ptr_cnt() {
 171     return _nested_threads_hazard_ptr_cnt;
 172   }
 173 
 174  public:
 175   void* operator new(size_t size) throw() { return allocate(size, true); }
 176   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 177     return allocate(size, false); }
 178   void  operator delete(void* p);
 179 
 180  protected:
 181   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 182  private:
 183 
 184   // ***************************************************************
 185   // Suspend and resume support
 186   // ***************************************************************
 187   //
 188   // VM suspend/resume no longer exists - it was once used for various
 189   // things including safepoints but was deprecated and finally removed
 190   // in Java 7. Because VM suspension was considered "internal" Java-level
 191   // suspension was considered "external", and this legacy naming scheme
 192   // remains.
 193   //
 194   // External suspend/resume requests come from JVM_SuspendThread,
 195   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 196   // ResumeThread. External
 197   // suspend requests cause _external_suspend to be set and external
 198   // resume requests cause _external_suspend to be cleared.
 199   // External suspend requests do not nest on top of other external
 200   // suspend requests. The higher level APIs reject suspend requests
 201   // for already suspended threads.
 202   //
 203   // The external_suspend
 204   // flag is checked by has_special_runtime_exit_condition() and java thread
 205   // will self-suspend when handle_special_runtime_exit_condition() is
 206   // called. Most uses of the _thread_blocked state in JavaThreads are
 207   // considered the same as being externally suspended; if the blocking
 208   // condition lifts, the JavaThread will self-suspend. Other places
 209   // where VM checks for external_suspend include:
 210   //   + mutex granting (do not enter monitors when thread is suspended)
 211   //   + state transitions from _thread_in_native
 212   //
 213   // In general, java_suspend() does not wait for an external suspend
 214   // request to complete. When it returns, the only guarantee is that
 215   // the _external_suspend field is true.
 216   //
 217   // wait_for_ext_suspend_completion() is used to wait for an external
 218   // suspend request to complete. External suspend requests are usually
 219   // followed by some other interface call that requires the thread to
 220   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 221   // the interface that requires quiescence, we give the JavaThread a
 222   // chance to self-suspend before we need it to be quiescent. This
 223   // improves overall suspend/query performance.
 224   //
 225   // _suspend_flags controls the behavior of java_ suspend/resume.
 226   // It must be set under the protection of SR_lock. Read from the flag is
 227   // OK without SR_lock as long as the value is only used as a hint.
 228   // (e.g., check _external_suspend first without lock and then recheck
 229   // inside SR_lock and finish the suspension)
 230   //
 231   // _suspend_flags is also overloaded for other "special conditions" so
 232   // that a single check indicates whether any special action is needed
 233   // eg. for async exceptions.
 234   // -------------------------------------------------------------------
 235   // Notes:
 236   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 237   // but we still update its value to keep other part of the system (mainly
 238   // JVMTI) happy. ThreadState is legacy code (see notes in
 239   // osThread.hpp).
 240   //
 241   // 2. It would be more natural if set_external_suspend() is private and
 242   // part of java_suspend(), but that probably would affect the suspend/query
 243   // performance. Need more investigation on this.
 244 
 245   // suspend/resume lock: used for self-suspend
 246   Monitor* _SR_lock;
 247 
 248  protected:
 249   enum SuspendFlags {
 250     // NOTE: avoid using the sign-bit as cc generates different test code
 251     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 252 
 253     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 254     _ext_suspended          = 0x40000000U, // thread has self-suspended
 255     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 256 
 257     _has_async_exception    = 0x00000001U, // there is a pending async exception
 258     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 259 
 260     _trace_flag             = 0x00000004U  // call tracing backend
 261   };
 262 
 263   // various suspension related flags - atomically updated
 264   // overloaded for async exception checking in check_special_condition_for_native_trans.
 265   volatile uint32_t _suspend_flags;
 266 
 267  private:
 268   int _num_nested_signal;
 269 
 270   DEBUG_ONLY(bool _suspendible_thread;)
 271 
 272  public:
 273   void enter_signal_handler() { _num_nested_signal++; }
 274   void leave_signal_handler() { _num_nested_signal--; }
 275   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 276 
 277 #ifdef ASSERT
 278   void set_suspendible_thread() {
 279     _suspendible_thread = true;
 280   }
 281 
 282   void clear_suspendible_thread() {
 283     _suspendible_thread = false;
 284   }
 285 
 286   bool is_suspendible_thread() { return _suspendible_thread; }
 287 #endif
 288 
 289  private:
 290   // Active_handles points to a block of handles
 291   JNIHandleBlock* _active_handles;
 292 
 293   // One-element thread local free list
 294   JNIHandleBlock* _free_handle_block;
 295 
 296   // Point to the last handle mark
 297   HandleMark* _last_handle_mark;
 298 
 299   // The parity of the last strong_roots iteration in which this thread was
 300   // claimed as a task.
 301   int _oops_do_parity;
 302 
 303   // Support for GlobalCounter
 304  private:
 305   volatile uintx _rcu_counter;
 306  public:
 307   volatile uintx* get_rcu_counter() {
 308     return &_rcu_counter;
 309   }
 310 
 311  public:
 312   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 313   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 314  private:
 315 
 316   // debug support for checking if code does allow safepoints or not
 317   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 318   // mutex, or blocking on an object synchronizer (Java locking).
 319   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 320   // If !allow_allocation(), then an assertion failure will happen during allocation
 321   // (Hence, !allow_safepoint() => !allow_allocation()).
 322   //
 323   // The two classes NoSafepointVerifier and No_Allocation_Verifier are used to set these counters.
 324   //
 325   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 326   debug_only(int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 327 
 328   // Used by SkipGCALot class.
 329   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 330 
 331   friend class NoAllocVerifier;
 332   friend class NoSafepointVerifier;
 333   friend class PauseNoSafepointVerifier;
 334   friend class GCLocker;
 335 
 336   volatile void* _polling_page;                 // Thread local polling page
 337 
 338   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 339   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 340                                                 // the Java heap

 341 
 342   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 343 
 344   int   _vm_operation_started_count;            // VM_Operation support
 345   int   _vm_operation_completed_count;          // VM_Operation support
 346 
 347   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 348                                                 // is waiting to lock
 349   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 350 
 351   // ObjectMonitor on which this thread called Object.wait()
 352   ObjectMonitor* _current_waiting_monitor;
 353 
 354   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 355  public:
 356   ObjectMonitor* omFreeList;
 357   int omFreeCount;                              // length of omFreeList
 358   int omFreeProvision;                          // reload chunk size
 359   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 360   int omInUseCount;                             // length of omInUseList
 361 
 362 #ifdef ASSERT
 363  private:
 364   bool _visited_for_critical_count;
 365 
 366  public:
 367   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 368   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 369 #endif
 370 
 371  public:
 372   enum {
 373     is_definitely_current_thread = true
 374   };
 375 
 376   // Constructor
 377   Thread();
 378   virtual ~Thread();
 379 
 380   // Manage Thread::current()
 381   void initialize_thread_current();
 382   void clear_thread_current(); // TLS cleanup needed before threads terminate
 383 
 384  public:
 385   // thread entry point
 386   virtual void run();
 387 
 388   // Testers
 389   virtual bool is_VM_thread()       const            { return false; }
 390   virtual bool is_Java_thread()     const            { return false; }
 391   virtual bool is_Compiler_thread() const            { return false; }
 392   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 393   virtual bool is_hidden_from_external_view() const  { return false; }
 394   virtual bool is_jvmti_agent_thread() const         { return false; }
 395   // True iff the thread can perform GC operations at a safepoint.
 396   // Generally will be true only of VM thread and parallel GC WorkGang
 397   // threads.
 398   virtual bool is_GC_task_thread() const             { return false; }
 399   virtual bool is_Watcher_thread() const             { return false; }
 400   virtual bool is_ConcurrentGC_thread() const        { return false; }
 401   virtual bool is_Named_thread() const               { return false; }
 402   virtual bool is_Worker_thread() const              { return false; }
 403 
 404   // Can this thread make Java upcalls
 405   virtual bool can_call_java() const                 { return false; }
 406 
 407   // Casts
 408   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 409 
 410   virtual char* name() const { return (char*)"Unknown thread"; }
 411 
 412   // Returns the current thread (ASSERTS if NULL)
 413   static inline Thread* current();
 414   // Returns the current thread, or NULL if not attached
 415   static inline Thread* current_or_null();
 416   // Returns the current thread, or NULL if not attached, and is
 417   // safe for use from signal-handlers
 418   static inline Thread* current_or_null_safe();
 419 
 420   // Common thread operations
 421 #ifdef ASSERT
 422   static void check_for_dangling_thread_pointer(Thread *thread);
 423 #endif
 424   static void set_priority(Thread* thread, ThreadPriority priority);
 425   static ThreadPriority get_priority(const Thread* const thread);
 426   static void start(Thread* thread);
 427   static void interrupt(Thread* thr);
 428   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 429 
 430   void set_native_thread_name(const char *name) {
 431     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 432     os::set_native_thread_name(name);
 433   }
 434 
 435   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 436   Monitor* SR_lock() const                       { return _SR_lock; }
 437 
 438   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 439 
 440   inline void set_suspend_flag(SuspendFlags f);
 441   inline void clear_suspend_flag(SuspendFlags f);
 442 
 443   inline void set_has_async_exception();
 444   inline void clear_has_async_exception();
 445 
 446   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 447 
 448   inline void set_critical_native_unlock();
 449   inline void clear_critical_native_unlock();
 450 
 451   inline void set_trace_flag();
 452   inline void clear_trace_flag();
 453 
 454   // Support for Unhandled Oop detection
 455   // Add the field for both, fastdebug and debug, builds to keep
 456   // Thread's fields layout the same.
 457   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 458 #ifdef CHECK_UNHANDLED_OOPS
 459  private:
 460   UnhandledOops* _unhandled_oops;
 461 #elif defined(ASSERT)
 462  private:
 463   void* _unhandled_oops;
 464 #endif
 465 #ifdef CHECK_UNHANDLED_OOPS
 466  public:
 467   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 468   // Mark oop safe for gc.  It may be stack allocated but won't move.
 469   void allow_unhandled_oop(oop *op) {
 470     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 471   }
 472   // Clear oops at safepoint so crashes point to unhandled oop violator
 473   void clear_unhandled_oops() {
 474     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 475   }
 476 #endif // CHECK_UNHANDLED_OOPS
 477 
 478  public:
 479 #ifndef PRODUCT
 480   bool skip_gcalot()           { return _skip_gcalot; }
 481   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 482 #endif
 483 
 484   // Installs a pending exception to be inserted later
 485   static void send_async_exception(oop thread_oop, oop java_throwable);
 486 
 487   // Resource area
 488   ResourceArea* resource_area() const            { return _resource_area; }
 489   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 490 
 491   OSThread* osthread() const                     { return _osthread;   }
 492   void set_osthread(OSThread* thread)            { _osthread = thread; }
 493 
 494   // JNI handle support
 495   JNIHandleBlock* active_handles() const         { return _active_handles; }
 496   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 497   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 498   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 499 
 500   // Internal handle support
 501   HandleArea* handle_area() const                { return _handle_area; }
 502   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 503 
 504   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 505   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 506 
 507   // Thread-Local Allocation Buffer (TLAB) support
 508   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 509   void initialize_tlab() {
 510     if (UseTLAB) {
 511       tlab().initialize();
 512     }
 513   }
 514 
 515   jlong allocated_bytes()               { return _allocated_bytes; }
 516   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 517   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 518   inline jlong cooked_allocated_bytes();


 519 
 520   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 521 
 522   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 523 
 524   // VM operation support
 525   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 526   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 527   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 528 
 529   // For tracking the heavyweight monitor the thread is pending on.
 530   ObjectMonitor* current_pending_monitor() {
 531     return _current_pending_monitor;
 532   }
 533   void set_current_pending_monitor(ObjectMonitor* monitor) {
 534     _current_pending_monitor = monitor;
 535   }
 536   void set_current_pending_monitor_is_from_java(bool from_java) {
 537     _current_pending_monitor_is_from_java = from_java;
 538   }
 539   bool current_pending_monitor_is_from_java() {
 540     return _current_pending_monitor_is_from_java;
 541   }
 542 
 543   // For tracking the ObjectMonitor on which this thread called Object.wait()
 544   ObjectMonitor* current_waiting_monitor() {
 545     return _current_waiting_monitor;
 546   }
 547   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 548     _current_waiting_monitor = monitor;
 549   }
 550 
 551   // GC support
 552   // Apply "f->do_oop" to all root oops in "this".
 553   //   Used by JavaThread::oops_do.
 554   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 555   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 556 
 557   // Handles the parallel case for the method below.
 558  private:
 559   bool claim_oops_do_par_case(int collection_parity);
 560  public:
 561   // Requires that "collection_parity" is that of the current roots
 562   // iteration.  If "is_par" is false, sets the parity of "this" to
 563   // "collection_parity", and returns "true".  If "is_par" is true,
 564   // uses an atomic instruction to set the current threads parity to
 565   // "collection_parity", if it is not already.  Returns "true" iff the
 566   // calling thread does the update, this indicates that the calling thread
 567   // has claimed the thread's stack as a root groop in the current
 568   // collection.
 569   bool claim_oops_do(bool is_par, int collection_parity) {
 570     if (!is_par) {
 571       _oops_do_parity = collection_parity;
 572       return true;
 573     } else {
 574       return claim_oops_do_par_case(collection_parity);
 575     }
 576   }
 577 
 578   // jvmtiRedefineClasses support
 579   void metadata_handles_do(void f(Metadata*));
 580 
 581   // Used by fast lock support
 582   virtual bool is_lock_owned(address adr) const;
 583 
 584   // Check if address is in the stack of the thread (not just for locks).
 585   // Warning: the method can only be used on the running thread
 586   bool is_in_stack(address adr) const;
 587   // Check if address is in the usable part of the stack (excludes protected
 588   // guard pages)
 589   bool is_in_usable_stack(address adr) const;
 590 
 591   // Sets this thread as starting thread. Returns failure if thread
 592   // creation fails due to lack of memory, too many threads etc.
 593   bool set_as_starting_thread();
 594 
 595 protected:
 596   // OS data associated with the thread
 597   OSThread* _osthread;  // Platform-specific thread information
 598 
 599   // Thread local resource area for temporary allocation within the VM
 600   ResourceArea* _resource_area;
 601 
 602   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 603 
 604   // Thread local handle area for allocation of handles within the VM
 605   HandleArea* _handle_area;
 606   GrowableArray<Metadata*>* _metadata_handles;
 607 
 608   // Support for stack overflow handling, get_thread, etc.
 609   address          _stack_base;
 610   size_t           _stack_size;
 611   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 612   int              _lgrp_id;
 613 
 614   volatile void** polling_page_addr() { return &_polling_page; }
 615 
 616  public:
 617   // Stack overflow support
 618   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 619   void    set_stack_base(address base) { _stack_base = base; }
 620   size_t  stack_size() const           { return _stack_size; }
 621   void    set_stack_size(size_t size)  { _stack_size = size; }
 622   address stack_end()  const           { return stack_base() - stack_size(); }
 623   void    record_stack_base_and_size();
 624 
 625   bool    on_local_stack(address adr) const {
 626     // QQQ this has knowledge of direction, ought to be a stack method
 627     return (_stack_base >= adr && adr >= stack_end());
 628   }
 629 
 630   uintptr_t self_raw_id()                    { return _self_raw_id; }
 631   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 632 
 633   int     lgrp_id() const        { return _lgrp_id; }
 634   void    set_lgrp_id(int value) { _lgrp_id = value; }
 635 
 636   // Printing
 637   virtual void print_on(outputStream* st) const;
 638   void print() const { print_on(tty); }
 639   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 640   void print_value_on(outputStream* st) const;
 641 
 642   // Debug-only code
 643 #ifdef ASSERT
 644  private:
 645   // Deadlock detection support for Mutex locks. List of locks own by thread.
 646   Monitor* _owned_locks;
 647   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 648   // thus the friendship
 649   friend class Mutex;
 650   friend class Monitor;
 651 
 652  public:
 653   void print_owned_locks_on(outputStream* st) const;
 654   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 655   Monitor* owned_locks() const                   { return _owned_locks;          }
 656   bool owns_locks() const                        { return owned_locks() != NULL; }
 657   bool owns_locks_but_compiled_lock() const;
 658   int oops_do_parity() const                     { return _oops_do_parity; }
 659 
 660   // Deadlock detection
 661   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 662   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 663   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 664 #endif
 665 
 666   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 667 
 668  private:
 669   volatile int _jvmti_env_iteration_count;
 670 
 671  public:
 672   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 673   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 674   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 675 
 676   // Code generation
 677   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 678   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 679   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 680 
 681   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 682   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 683 
 684   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 685 
 686 #define TLAB_FIELD_OFFSET(name) \
 687   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 688 
 689   TLAB_FIELD_OFFSET(start)
 690   TLAB_FIELD_OFFSET(end)
 691   TLAB_FIELD_OFFSET(top)
 692   TLAB_FIELD_OFFSET(pf_top)
 693   TLAB_FIELD_OFFSET(size)                   // desired_size
 694   TLAB_FIELD_OFFSET(refill_waste_limit)
 695   TLAB_FIELD_OFFSET(number_of_refills)
 696   TLAB_FIELD_OFFSET(fast_refill_waste)
 697   TLAB_FIELD_OFFSET(slow_allocations)
 698 
 699 #undef TLAB_FIELD_OFFSET
 700 
 701   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 702 
 703   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 704 
 705  public:
 706   volatile intptr_t _Stalled;
 707   volatile int _TypeTag;
 708   ParkEvent * _ParkEvent;                     // for synchronized()
 709   ParkEvent * _SleepEvent;                    // for Thread.sleep
 710   ParkEvent * _MutexEvent;                    // for native internal Mutex/Monitor
 711   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 712   int NativeSyncRecursion;                    // diagnostic
 713 
 714   volatile int _OnTrap;                       // Resume-at IP delta
 715   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 716   jint _hashStateX;                           // thread-specific hashCode generator state
 717   jint _hashStateY;
 718   jint _hashStateZ;
 719   void * _schedctl;
 720 
 721 
 722   volatile jint rng[4];                      // RNG for spin loop
 723 
 724   // Low-level leaf-lock primitives used to implement synchronization
 725   // and native monitor-mutex infrastructure.
 726   // Not for general synchronization use.
 727   static void SpinAcquire(volatile int * Lock, const char * Name);
 728   static void SpinRelease(volatile int * Lock);
 729   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 730   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 731   static void muxRelease(volatile intptr_t * Lock);
 732 };
 733 
 734 // Inline implementation of Thread::current()
 735 inline Thread* Thread::current() {
 736   Thread* current = current_or_null();
 737   assert(current != NULL, "Thread::current() called on detached thread");
 738   return current;
 739 }
 740 
 741 inline Thread* Thread::current_or_null() {
 742 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 743   return _thr_current;
 744 #else
 745   if (ThreadLocalStorage::is_initialized()) {
 746     return ThreadLocalStorage::thread();
 747   }
 748   return NULL;
 749 #endif
 750 }
 751 
 752 inline Thread* Thread::current_or_null_safe() {
 753   if (ThreadLocalStorage::is_initialized()) {
 754     return ThreadLocalStorage::thread();
 755   }
 756   return NULL;
 757 }
 758 
 759 // Name support for threads.  non-JavaThread subclasses with multiple
 760 // uniquely named instances should derive from this.
 761 class NamedThread: public Thread {
 762   friend class VMStructs;
 763   enum {
 764     max_name_len = 64
 765   };
 766  private:
 767   char* _name;
 768   // log JavaThread being processed by oops_do
 769   JavaThread* _processed_thread;
 770   uint _gc_id; // The current GC id when a thread takes part in GC
 771 
 772  public:
 773   NamedThread();
 774   ~NamedThread();
 775   // May only be called once per thread.
 776   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 777   void initialize_named_thread();
 778   virtual bool is_Named_thread() const { return true; }
 779   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 780   JavaThread *processed_thread() { return _processed_thread; }
 781   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 782   virtual void print_on(outputStream* st) const;
 783 
 784   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 785   uint gc_id() { return _gc_id; }
 786 };
 787 
 788 // Worker threads are named and have an id of an assigned work.
 789 class WorkerThread: public NamedThread {
 790  private:
 791   uint _id;
 792  public:
 793   WorkerThread() : _id(0)               { }
 794   virtual bool is_Worker_thread() const { return true; }
 795 
 796   virtual WorkerThread* as_Worker_thread() const {
 797     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 798     return (WorkerThread*) this;
 799   }
 800 
 801   void set_id(uint work_id)             { _id = work_id; }
 802   uint id() const                       { return _id; }
 803 };
 804 
 805 // A single WatcherThread is used for simulating timer interrupts.
 806 class WatcherThread: public Thread {
 807   friend class VMStructs;
 808  public:
 809   virtual void run();
 810 
 811  private:
 812   static WatcherThread* _watcher_thread;
 813 
 814   static bool _startable;
 815   // volatile due to at least one lock-free read
 816   volatile static bool _should_terminate;
 817  public:
 818   enum SomeConstants {
 819     delay_interval = 10                          // interrupt delay in milliseconds
 820   };
 821 
 822   // Constructor
 823   WatcherThread();
 824 
 825   // No destruction allowed
 826   ~WatcherThread() {
 827     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 828   }
 829 
 830   // Tester
 831   bool is_Watcher_thread() const                 { return true; }
 832 
 833   // Printing
 834   char* name() const { return (char*)"VM Periodic Task Thread"; }
 835   void print_on(outputStream* st) const;
 836   void unpark();
 837 
 838   // Returns the single instance of WatcherThread
 839   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 840 
 841   // Create and start the single instance of WatcherThread, or stop it on shutdown
 842   static void start();
 843   static void stop();
 844   // Only allow start once the VM is sufficiently initialized
 845   // Otherwise the first task to enroll will trigger the start
 846   static void make_startable();
 847  private:
 848   int sleep() const;
 849 };
 850 
 851 
 852 class CompilerThread;
 853 
 854 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 855 
 856 class JavaThread: public Thread {
 857   friend class VMStructs;
 858   friend class JVMCIVMStructs;
 859   friend class WhiteBox;
 860  private:
 861   JavaThread*    _next;                          // The next thread in the Threads list
 862   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 863   oop            _threadObj;                     // The Java level thread object
 864 
 865 #ifdef ASSERT
 866  private:
 867   int _java_call_counter;
 868 
 869  public:
 870   int  java_call_counter()                       { return _java_call_counter; }
 871   void inc_java_call_counter()                   { _java_call_counter++; }
 872   void dec_java_call_counter() {
 873     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 874     _java_call_counter--;
 875   }
 876  private:  // restore original namespace restriction
 877 #endif  // ifdef ASSERT
 878 
 879 #ifndef PRODUCT
 880  public:
 881   enum {
 882     jump_ring_buffer_size = 16
 883   };
 884  private:  // restore original namespace restriction
 885 #endif
 886 
 887   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 888 
 889   ThreadFunction _entry_point;
 890 
 891   JNIEnv        _jni_environment;
 892 
 893   // Deopt support
 894   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 895 
 896   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 897                                                  // transition out of native
 898   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 899   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 900   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 901   // Because deoptimization is lazy we must save jvmti requests to set locals
 902   // in compiled frames until we deoptimize and we have an interpreter frame.
 903   // This holds the pointer to array (yeah like there might be more than one) of
 904   // description of compiled vframes that have locals that need to be updated.
 905   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 906 
 907   // Handshake value for fixing 6243940. We need a place for the i2c
 908   // adapter to store the callee Method*. This value is NEVER live
 909   // across a gc point so it does NOT have to be gc'd
 910   // The handshake is open ended since we can't be certain that it will
 911   // be NULLed. This is because we rarely ever see the race and end up
 912   // in handle_wrong_method which is the backend of the handshake. See
 913   // code in i2c adapters and handle_wrong_method.
 914 
 915   Method*       _callee_target;
 916 
 917   // Used to pass back results to the interpreter or generated code running Java code.
 918   oop           _vm_result;    // oop result is GC-preserved
 919   Metadata*     _vm_result_2;  // non-oop result
 920 
 921   // See ReduceInitialCardMarks: this holds the precise space interval of
 922   // the most recent slow path allocation for which compiled code has
 923   // elided card-marks for performance along the fast-path.
 924   MemRegion     _deferred_card_mark;
 925 
 926   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 927                                                  // allocated during deoptimization
 928                                                  // and by JNI_MonitorEnter/Exit
 929 
 930   // Async. requests support
 931   enum AsyncRequests {
 932     _no_async_condition = 0,
 933     _async_exception,
 934     _async_unsafe_access_error
 935   };
 936   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 937   oop           _pending_async_exception;
 938 
 939   // Safepoint support
 940  public:                                         // Expose _thread_state for SafeFetchInt()
 941   volatile JavaThreadState _thread_state;
 942  private:
 943   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 944   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 945 
 946   // JavaThread termination support
 947   enum TerminatedTypes {
 948     _not_terminated = 0xDEAD - 2,
 949     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 950     _thread_terminated,                          // JavaThread is removed from thread list
 951     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 952                                                  // only VM_Exit can set _vm_exited
 953   };
 954 
 955   // In general a JavaThread's _terminated field transitions as follows:
 956   //
 957   //   _not_terminated => _thread_exiting => _thread_terminated
 958   //
 959   // _vm_exited is a special value to cover the case of a JavaThread
 960   // executing native code after the VM itself is terminated.
 961   volatile TerminatedTypes _terminated;
 962   // suspend/resume support
 963   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 964   jint                  _in_deopt_handler;       // count of deoptimization
 965                                                  // handlers thread is in
 966   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 967   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 968                                                          // never locked) when throwing an exception. Used by interpreter only.
 969 
 970   // JNI attach states:
 971   enum JNIAttachStates {
 972     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 973     _attaching_via_jni,          // thread is attaching via JNI
 974     _attached_via_jni            // thread has attached via JNI
 975   };
 976 
 977   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 978   // A native thread that is attaching via JNI starts with a value
 979   // of _attaching_via_jni and transitions to _attached_via_jni.
 980   volatile JNIAttachStates _jni_attach_state;
 981 
 982  public:
 983   // State of the stack guard pages for this thread.
 984   enum StackGuardState {
 985     stack_guard_unused,         // not needed
 986     stack_guard_reserved_disabled,
 987     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
 988     stack_guard_enabled         // enabled
 989   };
 990 
 991  private:
 992 
 993 #if INCLUDE_JVMCI
 994   // The _pending_* fields below are used to communicate extra information
 995   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 996 
 997   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 998   int       _pending_deoptimization;
 999 
1000   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1001   // before the monitor has been acquired.
1002   bool      _pending_monitorenter;
1003 
1004   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1005   bool      _pending_transfer_to_interpreter;
1006 
1007   // Guard for re-entrant call to JVMCIRuntime::adjust_comp_level
1008   bool      _adjusting_comp_level;
1009 
1010   // An object that JVMCI compiled code can use to further describe and
1011   // uniquely identify the  speculative optimization guarded by the uncommon trap
1012   oop       _pending_failed_speculation;
1013 
1014   // These fields are mutually exclusive in terms of live ranges.
1015   union {
1016     // Communicates the pc at which the most recent implicit exception occurred
1017     // from the signal handler to a deoptimization stub.
1018     address   _implicit_exception_pc;
1019 
1020     // Communicates an alternative call target to an i2c stub from a JavaCall .
1021     address   _alternate_call_target;
1022   } _jvmci;
1023 
1024   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1025   jlong*    _jvmci_counters;
1026 
1027  public:
1028   static jlong* _jvmci_old_thread_counters;
1029   static void collect_counters(typeArrayOop array);
1030  private:
1031 #endif // INCLUDE_JVMCI
1032 
1033   StackGuardState  _stack_guard_state;
1034 
1035   // Precompute the limit of the stack as used in stack overflow checks.
1036   // We load it from here to simplify the stack overflow check in assembly.
1037   address          _stack_overflow_limit;
1038   address          _reserved_stack_activation;
1039 
1040   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1041   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1042   // code)
1043   volatile oop     _exception_oop;               // Exception thrown in compiled code
1044   volatile address _exception_pc;                // PC where exception happened
1045   volatile address _exception_handler_pc;        // PC for handler of exception
1046   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1047 
1048  private:
1049   // support for JNI critical regions
1050   jint    _jni_active_critical;                  // count of entries into JNI critical region
1051 
1052   // Checked JNI: function name requires exception check
1053   char* _pending_jni_exception_check_fn;
1054 
1055   // For deadlock detection.
1056   int _depth_first_number;
1057 
1058   // JVMTI PopFrame support
1059   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1060   int _popframe_condition;
1061 
1062   // If reallocation of scalar replaced objects fails, we throw OOM
1063   // and during exception propagation, pop the top
1064   // _frames_to_pop_failed_realloc frames, the ones that reference
1065   // failed reallocations.
1066   int _frames_to_pop_failed_realloc;
1067 
1068 #ifndef PRODUCT
1069   int _jmp_ring_index;
1070   struct {
1071     // We use intptr_t instead of address so debugger doesn't try and display strings
1072     intptr_t _target;
1073     intptr_t _instruction;
1074     const char*  _file;
1075     int _line;
1076   }   _jmp_ring[jump_ring_buffer_size];
1077 #endif // PRODUCT
1078 
1079   friend class VMThread;
1080   friend class ThreadWaitTransition;
1081   friend class VM_Exit;
1082 
1083   void initialize();                             // Initialized the instance variables
1084 
1085  public:
1086   // Constructor
1087   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1088   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1089   ~JavaThread();
1090 
1091 #ifdef ASSERT
1092   // verify this JavaThread hasn't be published in the Threads::list yet
1093   void verify_not_published();
1094 #endif
1095 
1096   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1097   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1098     _jni_environment.functions = functionTable;
1099   }
1100   struct JNINativeInterface_* get_jni_functions() {
1101     return (struct JNINativeInterface_ *)_jni_environment.functions;
1102   }
1103 
1104   // This function is called at thread creation to allow
1105   // platform specific thread variables to be initialized.
1106   void cache_global_variables();
1107 
1108   // Executes Shutdown.shutdown()
1109   void invoke_shutdown_hooks();
1110 
1111   // Cleanup on thread exit
1112   enum ExitType {
1113     normal_exit,
1114     jni_detach
1115   };
1116   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1117 
1118   void cleanup_failed_attach_current_thread();
1119 
1120   // Testers
1121   virtual bool is_Java_thread() const            { return true;  }
1122   virtual bool can_call_java() const             { return true; }
1123 
1124   // Thread chain operations
1125   JavaThread* next() const                       { return _next; }
1126   void set_next(JavaThread* p)                   { _next = p; }
1127 
1128   // Thread oop. threadObj() can be NULL for initial JavaThread
1129   // (or for threads attached via JNI)
1130   oop threadObj() const                          { return _threadObj; }
1131   void set_threadObj(oop p)                      { _threadObj = p; }
1132 
1133   ThreadPriority java_priority() const;          // Read from threadObj()
1134 
1135   // Prepare thread and add to priority queue.  If a priority is
1136   // not specified, use the priority of the thread object. Threads_lock
1137   // must be held while this function is called.
1138   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1139 
1140   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1141   address saved_exception_pc()                   { return _saved_exception_pc; }
1142 
1143 
1144   ThreadFunction entry_point() const             { return _entry_point; }
1145 
1146   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1147   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1148 
1149   // Last frame anchor routines
1150 
1151   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1152 
1153   // last_Java_sp
1154   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1155   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1156 
1157   // last_Java_pc
1158 
1159   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1160 
1161   // Safepoint support
1162 #if !(defined(PPC64) || defined(AARCH64))
1163   JavaThreadState thread_state() const           { return _thread_state; }
1164   void set_thread_state(JavaThreadState s)       { _thread_state = s;    }
1165 #else
1166   // Use membars when accessing volatile _thread_state. See
1167   // Threads::create_vm() for size checks.
1168   inline JavaThreadState thread_state() const;
1169   inline void set_thread_state(JavaThreadState s);
1170 #endif
1171   ThreadSafepointState *safepoint_state() const  { return _safepoint_state; }
1172   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1173   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1174 
1175   // JavaThread termination and lifecycle support:
1176   void smr_delete();
1177   bool on_thread_list() const { return _on_thread_list; }
1178   void set_on_thread_list() { _on_thread_list = true; }
1179 
1180   // thread has called JavaThread::exit() or is terminated
1181   bool is_exiting() const;
1182   // thread is terminated (no longer on the threads list); we compare
1183   // against the two non-terminated values so that a freed JavaThread
1184   // will also be considered terminated.
1185   bool check_is_terminated(TerminatedTypes l_terminated) const {
1186     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1187   }
1188   bool is_terminated() const;
1189   void set_terminated(TerminatedTypes t);
1190   // special for Threads::remove() which is static:
1191   void set_terminated_value();
1192   void block_if_vm_exited();
1193 
1194   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1195   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1196 
1197   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1198   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1199 
1200   inline void set_polling_page(void* poll_value);
1201   inline volatile void* get_polling_page();
1202 
1203  private:
1204   // Support for thread handshake operations
1205   HandshakeState _handshake;
1206  public:
1207   void set_handshake_operation(HandshakeOperation* op) {
1208     _handshake.set_operation(this, op);
1209   }
1210 
1211   bool has_handshake() const {
1212     return _handshake.has_operation();
1213   }
1214 
1215   void cancel_handshake() {
1216     _handshake.cancel(this);
1217   }
1218 
1219   void handshake_process_by_self() {
1220     _handshake.process_by_self(this);
1221   }
1222 
1223   void handshake_process_by_vmthread() {
1224     _handshake.process_by_vmthread(this);
1225   }
1226 
1227   // Suspend/resume support for JavaThread
1228  private:
1229   inline void set_ext_suspended();
1230   inline void clear_ext_suspended();
1231 
1232  public:
1233   void java_suspend();
1234   void java_resume();
1235   int  java_suspend_self();
1236 
1237   void check_and_wait_while_suspended() {
1238     assert(JavaThread::current() == this, "sanity check");
1239 
1240     bool do_self_suspend;
1241     do {
1242       // were we externally suspended while we were waiting?
1243       do_self_suspend = handle_special_suspend_equivalent_condition();
1244       if (do_self_suspend) {
1245         // don't surprise the thread that suspended us by returning
1246         java_suspend_self();
1247         set_suspend_equivalent();
1248       }
1249     } while (do_self_suspend);
1250   }
1251   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1252   // Check for async exception in addition to safepoint and suspend request.
1253   static void check_special_condition_for_native_trans(JavaThread *thread);
1254 
1255   // Same as check_special_condition_for_native_trans but finishes the
1256   // transition into thread_in_Java mode so that it can potentially
1257   // block.
1258   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1259 
1260   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1261   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1262     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1263     // Warning: is_ext_suspend_completed() may temporarily drop the
1264     // SR_lock to allow the thread to reach a stable thread state if
1265     // it is currently in a transient thread state.
1266     return is_ext_suspend_completed(false /* !called_by_wait */,
1267                                     SuspendRetryDelay, bits);
1268   }
1269 
1270   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1271   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1272   // passed as the count and delay parameters. Experiments with specific
1273   // calls to wait_for_ext_suspend_completion() can be done by passing
1274   // other values in the code. Experiments with all calls can be done
1275   // via the appropriate -XX options.
1276   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1277 
1278   // test for suspend - most (all?) of these should go away
1279   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1280 
1281   inline void set_external_suspend();
1282   inline void clear_external_suspend();
1283 
1284   inline void set_deopt_suspend();
1285   inline void clear_deopt_suspend();
1286   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1287 
1288   bool is_external_suspend() const {
1289     return (_suspend_flags & _external_suspend) != 0;
1290   }
1291   // Whenever a thread transitions from native to vm/java it must suspend
1292   // if external|deopt suspend is present.
1293   bool is_suspend_after_native() const {
1294     return (_suspend_flags & (_external_suspend | _deopt_suspend)) != 0;
1295   }
1296 
1297   // external suspend request is completed
1298   bool is_ext_suspended() const {
1299     return (_suspend_flags & _ext_suspended) != 0;
1300   }
1301 
1302   bool is_external_suspend_with_lock() const {
1303     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1304     return is_external_suspend();
1305   }
1306 
1307   // Special method to handle a pending external suspend request
1308   // when a suspend equivalent condition lifts.
1309   bool handle_special_suspend_equivalent_condition() {
1310     assert(is_suspend_equivalent(),
1311            "should only be called in a suspend equivalence condition");
1312     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1313     bool ret = is_external_suspend();
1314     if (!ret) {
1315       // not about to self-suspend so clear suspend equivalence
1316       clear_suspend_equivalent();
1317     }
1318     // implied else:
1319     // We have a pending external suspend request so we leave the
1320     // suspend_equivalent flag set until java_suspend_self() sets
1321     // the ext_suspended flag and clears the suspend_equivalent
1322     // flag. This insures that wait_for_ext_suspend_completion()
1323     // will return consistent values.
1324     return ret;
1325   }
1326 
1327   // utility methods to see if we are doing some kind of suspension
1328   bool is_being_ext_suspended() const            {
1329     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1330     return is_ext_suspended() || is_external_suspend();
1331   }
1332 
1333   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1334 
1335   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1336   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1337 
1338   // Thread.stop support
1339   void send_thread_stop(oop throwable);
1340   AsyncRequests clear_special_runtime_exit_condition() {
1341     AsyncRequests x = _special_runtime_exit_condition;
1342     _special_runtime_exit_condition = _no_async_condition;
1343     return x;
1344   }
1345 
1346   // Are any async conditions present?
1347   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1348 
1349   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1350 
1351   // these next two are also used for self-suspension and async exception support
1352   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1353 
1354   // Return true if JavaThread has an asynchronous condition or
1355   // if external suspension is requested.
1356   bool has_special_runtime_exit_condition() {
1357     // Because we don't use is_external_suspend_with_lock
1358     // it is possible that we won't see an asynchronous external suspend
1359     // request that has just gotten started, i.e., SR_lock grabbed but
1360     // _external_suspend field change either not made yet or not visible
1361     // yet. However, this is okay because the request is asynchronous and
1362     // we will see the new flag value the next time through. It's also
1363     // possible that the external suspend request is dropped after
1364     // we have checked is_external_suspend(), we will recheck its value
1365     // under SR_lock in java_suspend_self().
1366     return (_special_runtime_exit_condition != _no_async_condition) ||
1367             is_external_suspend() || is_trace_suspend();
1368   }
1369 
1370   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1371 
1372   inline void set_pending_async_exception(oop e);
1373 
1374   // Fast-locking support
1375   bool is_lock_owned(address adr) const;
1376 
1377   // Accessors for vframe array top
1378   // The linked list of vframe arrays are sorted on sp. This means when we
1379   // unpack the head must contain the vframe array to unpack.
1380   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1381   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1382 
1383   // Side structure for deferring update of java frame locals until deopt occurs
1384   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1385   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1386 
1387   // These only really exist to make debugging deopt problems simpler
1388 
1389   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1390   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1391 
1392   // The special resourceMark used during deoptimization
1393 
1394   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1395   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1396 
1397   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1398   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1399   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1400 
1401   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1402   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1403 
1404   Method*    callee_target() const               { return _callee_target; }
1405   void set_callee_target  (Method* x)          { _callee_target   = x; }
1406 
1407   // Oop results of vm runtime calls
1408   oop  vm_result() const                         { return _vm_result; }
1409   void set_vm_result  (oop x)                    { _vm_result   = x; }
1410 
1411   Metadata*    vm_result_2() const               { return _vm_result_2; }
1412   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1413 
1414   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1415   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1416 
1417 #if INCLUDE_JVMCI
1418   int  pending_deoptimization() const             { return _pending_deoptimization; }
1419   oop  pending_failed_speculation() const         { return _pending_failed_speculation; }
1420   bool adjusting_comp_level() const               { return _adjusting_comp_level; }
1421   void set_adjusting_comp_level(bool b)           { _adjusting_comp_level = b; }
1422   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1423   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1424   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1425   void set_pending_failed_speculation(oop failed_speculation) { _pending_failed_speculation = failed_speculation; }
1426   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1427   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1428   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1429 #endif // INCLUDE_JVMCI
1430 
1431   // Exception handling for compiled methods
1432   oop      exception_oop() const                 { return _exception_oop; }
1433   address  exception_pc() const                  { return _exception_pc; }
1434   address  exception_handler_pc() const          { return _exception_handler_pc; }
1435   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1436 
1437   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1438   void set_exception_pc(address a)               { _exception_pc = a; }
1439   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1440   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1441 
1442   void clear_exception_oop_and_pc() {
1443     set_exception_oop(NULL);
1444     set_exception_pc(NULL);
1445   }
1446 
1447   // Stack overflow support
1448   //
1449   //  (small addresses)
1450   //
1451   //  --  <-- stack_end()                   ---
1452   //  |                                      |
1453   //  |  red pages                           |
1454   //  |                                      |
1455   //  --  <-- stack_red_zone_base()          |
1456   //  |                                      |
1457   //  |                                     guard
1458   //  |  yellow pages                       zone
1459   //  |                                      |
1460   //  |                                      |
1461   //  --  <-- stack_yellow_zone_base()       |
1462   //  |                                      |
1463   //  |                                      |
1464   //  |  reserved pages                      |
1465   //  |                                      |
1466   //  --  <-- stack_reserved_zone_base()    ---      ---
1467   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1468   //                                                  |   zone
1469   //                                                 \|/  size
1470   //  some untouched memory                          ---
1471   //
1472   //
1473   //  --
1474   //  |
1475   //  |  shadow zone
1476   //  |
1477   //  --
1478   //  x    frame n
1479   //  --
1480   //  x    frame n-1
1481   //  x
1482   //  --
1483   //  ...
1484   //
1485   //  --
1486   //  x    frame 0
1487   //  --  <-- stack_base()
1488   //
1489   //  (large addresses)
1490   //
1491 
1492  private:
1493   // These values are derived from flags StackRedPages, StackYellowPages,
1494   // StackReservedPages and StackShadowPages. The zone size is determined
1495   // ergonomically if page_size > 4K.
1496   static size_t _stack_red_zone_size;
1497   static size_t _stack_yellow_zone_size;
1498   static size_t _stack_reserved_zone_size;
1499   static size_t _stack_shadow_zone_size;
1500  public:
1501   inline size_t stack_available(address cur_sp);
1502 
1503   static size_t stack_red_zone_size() {
1504     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1505     return _stack_red_zone_size;
1506   }
1507   static void set_stack_red_zone_size(size_t s) {
1508     assert(is_aligned(s, os::vm_page_size()),
1509            "We can not protect if the red zone size is not page aligned.");
1510     assert(_stack_red_zone_size == 0, "This should be called only once.");
1511     _stack_red_zone_size = s;
1512   }
1513   address stack_red_zone_base() {
1514     return (address)(stack_end() + stack_red_zone_size());
1515   }
1516   bool in_stack_red_zone(address a) {
1517     return a <= stack_red_zone_base() && a >= stack_end();
1518   }
1519 
1520   static size_t stack_yellow_zone_size() {
1521     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1522     return _stack_yellow_zone_size;
1523   }
1524   static void set_stack_yellow_zone_size(size_t s) {
1525     assert(is_aligned(s, os::vm_page_size()),
1526            "We can not protect if the yellow zone size is not page aligned.");
1527     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1528     _stack_yellow_zone_size = s;
1529   }
1530 
1531   static size_t stack_reserved_zone_size() {
1532     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1533     return _stack_reserved_zone_size;
1534   }
1535   static void set_stack_reserved_zone_size(size_t s) {
1536     assert(is_aligned(s, os::vm_page_size()),
1537            "We can not protect if the reserved zone size is not page aligned.");
1538     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1539     _stack_reserved_zone_size = s;
1540   }
1541   address stack_reserved_zone_base() {
1542     return (address)(stack_end() +
1543                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1544   }
1545   bool in_stack_reserved_zone(address a) {
1546     return (a <= stack_reserved_zone_base()) &&
1547            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1548   }
1549 
1550   static size_t stack_yellow_reserved_zone_size() {
1551     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1552   }
1553   bool in_stack_yellow_reserved_zone(address a) {
1554     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1555   }
1556 
1557   // Size of red + yellow + reserved zones.
1558   static size_t stack_guard_zone_size() {
1559     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1560   }
1561 
1562   static size_t stack_shadow_zone_size() {
1563     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1564     return _stack_shadow_zone_size;
1565   }
1566   static void set_stack_shadow_zone_size(size_t s) {
1567     // The shadow area is not allocated or protected, so
1568     // it needs not be page aligned.
1569     // But the stack bang currently assumes that it is a
1570     // multiple of page size. This guarantees that the bang
1571     // loop touches all pages in the shadow zone.
1572     // This can be guaranteed differently, as well.  E.g., if
1573     // the page size is a multiple of 4K, banging in 4K steps
1574     // suffices to touch all pages. (Some pages are banged
1575     // several times, though.)
1576     assert(is_aligned(s, os::vm_page_size()),
1577            "Stack bang assumes multiple of page size.");
1578     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1579     _stack_shadow_zone_size = s;
1580   }
1581 
1582   void create_stack_guard_pages();
1583   void remove_stack_guard_pages();
1584 
1585   void enable_stack_reserved_zone();
1586   void disable_stack_reserved_zone();
1587   void enable_stack_yellow_reserved_zone();
1588   void disable_stack_yellow_reserved_zone();
1589   void enable_stack_red_zone();
1590   void disable_stack_red_zone();
1591 
1592   inline bool stack_guard_zone_unused();
1593   inline bool stack_yellow_reserved_zone_disabled();
1594   inline bool stack_reserved_zone_disabled();
1595   inline bool stack_guards_enabled();
1596 
1597   address reserved_stack_activation() const { return _reserved_stack_activation; }
1598   void set_reserved_stack_activation(address addr) {
1599     assert(_reserved_stack_activation == stack_base()
1600             || _reserved_stack_activation == NULL
1601             || addr == stack_base(), "Must not be set twice");
1602     _reserved_stack_activation = addr;
1603   }
1604 
1605   // Attempt to reguard the stack after a stack overflow may have occurred.
1606   // Returns true if (a) guard pages are not needed on this thread, (b) the
1607   // pages are already guarded, or (c) the pages were successfully reguarded.
1608   // Returns false if there is not enough stack space to reguard the pages, in
1609   // which case the caller should unwind a frame and try again.  The argument
1610   // should be the caller's (approximate) sp.
1611   bool reguard_stack(address cur_sp);
1612   // Similar to above but see if current stackpoint is out of the guard area
1613   // and reguard if possible.
1614   bool reguard_stack(void);
1615 
1616   address stack_overflow_limit() { return _stack_overflow_limit; }
1617   void set_stack_overflow_limit() {
1618     _stack_overflow_limit =
1619       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1620   }
1621 
1622   // Misc. accessors/mutators
1623   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1624   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1625   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1626 
1627 #ifndef PRODUCT
1628   void record_jump(address target, address instr, const char* file, int line);
1629 #endif // PRODUCT
1630 
1631   // For assembly stub generation
1632   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1633 #ifndef PRODUCT
1634   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1635   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1636 #endif // PRODUCT
1637   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1638   static ByteSize pending_jni_exception_check_fn_offset() {
1639     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1640   }
1641   static ByteSize last_Java_sp_offset() {
1642     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1643   }
1644   static ByteSize last_Java_pc_offset() {
1645     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1646   }
1647   static ByteSize frame_anchor_offset() {
1648     return byte_offset_of(JavaThread, _anchor);
1649   }
1650   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1651   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1652   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1653   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1654   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1655   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1656 #if INCLUDE_JVMCI
1657   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1658   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1659   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1660   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1661   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1662   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1663 #endif // INCLUDE_JVMCI
1664   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1665   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1666   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1667   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1668   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1669   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1670   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1671   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1672 
1673   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1674   static ByteSize should_post_on_exceptions_flag_offset() {
1675     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1676   }
1677 
1678   // Returns the jni environment for this thread
1679   JNIEnv* jni_environment()                      { return &_jni_environment; }
1680 
1681   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1682     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1683     // Only return NULL if thread is off the thread list; starting to
1684     // exit should not return NULL.
1685     if (thread_from_jni_env->is_terminated()) {
1686       thread_from_jni_env->block_if_vm_exited();
1687       return NULL;
1688     } else {
1689       return thread_from_jni_env;
1690     }
1691   }
1692 
1693   // JNI critical regions. These can nest.
1694   bool in_critical()    { return _jni_active_critical > 0; }
1695   bool in_last_critical()  { return _jni_active_critical == 1; }
1696   void enter_critical() {
1697     assert(Thread::current() == this ||
1698            (Thread::current()->is_VM_thread() &&
1699            SafepointSynchronize::is_synchronizing()),
1700            "this must be current thread or synchronizing");
1701     _jni_active_critical++;
1702   }
1703   void exit_critical() {
1704     assert(Thread::current() == this, "this must be current thread");
1705     _jni_active_critical--;
1706     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1707   }
1708 
1709   // Checked JNI: is the programmer required to check for exceptions, if so specify
1710   // which function name. Returning to a Java frame should implicitly clear the
1711   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1712   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1713   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1714   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1715   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1716   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1717   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1718 
1719   // For deadlock detection
1720   int depth_first_number() { return _depth_first_number; }
1721   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1722 
1723  private:
1724   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1725 
1726  public:
1727   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1728   void add_monitor_chunk(MonitorChunk* chunk);
1729   void remove_monitor_chunk(MonitorChunk* chunk);
1730   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1731   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1732   void dec_in_deopt_handler() {
1733     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1734     if (_in_deopt_handler > 0) { // robustness
1735       _in_deopt_handler--;
1736     }
1737   }
1738 
1739  private:
1740   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1741 
1742  public:
1743 
1744   // Frame iteration; calls the function f for all frames on the stack
1745   void frames_do(void f(frame*, const RegisterMap*));
1746 
1747   // Memory operations
1748   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1749 
1750   // Sweeper operations
1751   virtual void nmethods_do(CodeBlobClosure* cf);
1752 
1753   // RedefineClasses Support
1754   void metadata_do(void f(Metadata*));
1755 
1756   // Misc. operations
1757   char* name() const { return (char*)get_thread_name(); }
1758   void print_on(outputStream* st) const;
1759   void print_value();
1760   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1761   void print_thread_state() const                      PRODUCT_RETURN;
1762   void print_on_error(outputStream* st, char* buf, int buflen) const;
1763   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1764   void verify();
1765   const char* get_thread_name() const;
1766  private:
1767   // factor out low-level mechanics for use in both normal and error cases
1768   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1769  public:
1770   const char* get_threadgroup_name() const;
1771   const char* get_parent_name() const;
1772 
1773   // Accessing frames
1774   frame last_frame() {
1775     _anchor.make_walkable(this);
1776     return pd_last_frame();
1777   }
1778   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1779 
1780   // Returns method at 'depth' java or native frames down the stack
1781   // Used for security checks
1782   Klass* security_get_caller_class(int depth);
1783 
1784   // Print stack trace in external format
1785   void print_stack_on(outputStream* st);
1786   void print_stack() { print_stack_on(tty); }
1787 
1788   // Print stack traces in various internal formats
1789   void trace_stack()                             PRODUCT_RETURN;
1790   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1791   void trace_frames()                            PRODUCT_RETURN;
1792   void trace_oops()                              PRODUCT_RETURN;
1793 
1794   // Print an annotated view of the stack frames
1795   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1796   void validate_frame_layout() {
1797     print_frame_layout(0, true);
1798   }
1799 
1800   // Returns the number of stack frames on the stack
1801   int depth() const;
1802 
1803   // Function for testing deoptimization
1804   void deoptimize();
1805   void make_zombies();
1806 
1807   void deoptimized_wrt_marked_nmethods();
1808 
1809  public:
1810   // Returns the running thread as a JavaThread
1811   static inline JavaThread* current();
1812 
1813   // Returns the active Java thread.  Do not use this if you know you are calling
1814   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1815   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1816   // operation.  You may not want that either.
1817   static JavaThread* active();
1818 
1819   inline CompilerThread* as_CompilerThread();
1820 
1821  public:
1822   virtual void run();
1823   void thread_main_inner();
1824 
1825  private:
1826   // PRIVILEGED STACK
1827   PrivilegedElement*  _privileged_stack_top;
1828   GrowableArray<oop>* _array_for_gc;
1829  public:
1830 
1831   // Returns the privileged_stack information.
1832   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1833   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1834   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1835 
1836  public:
1837   // Thread local information maintained by JVMTI.
1838   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1839   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1840   // getter is used to get this JavaThread's JvmtiThreadState if it has
1841   // one which means NULL can be returned. JvmtiThreadState::state_for()
1842   // is used to get the specified JavaThread's JvmtiThreadState if it has
1843   // one or it allocates a new JvmtiThreadState for the JavaThread and
1844   // returns it. JvmtiThreadState::state_for() will return NULL only if
1845   // the specified JavaThread is exiting.
1846   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1847   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1848   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1849   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1850 
1851   // JVMTI PopFrame support
1852   // Setting and clearing popframe_condition
1853   // All of these enumerated values are bits. popframe_pending
1854   // indicates that a PopFrame() has been requested and not yet been
1855   // completed. popframe_processing indicates that that PopFrame() is in
1856   // the process of being completed. popframe_force_deopt_reexecution_bit
1857   // indicates that special handling is required when returning to a
1858   // deoptimized caller.
1859   enum PopCondition {
1860     popframe_inactive                      = 0x00,
1861     popframe_pending_bit                   = 0x01,
1862     popframe_processing_bit                = 0x02,
1863     popframe_force_deopt_reexecution_bit   = 0x04
1864   };
1865   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1866   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1867   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1868   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1869   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1870   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1871   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1872   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1873 #ifdef CC_INTERP
1874   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1875   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1876   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1877   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1878   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1879 #endif
1880 
1881   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1882   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1883   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1884 
1885  private:
1886   // Saved incoming arguments to popped frame.
1887   // Used only when popped interpreted frame returns to deoptimized frame.
1888   void*    _popframe_preserved_args;
1889   int      _popframe_preserved_args_size;
1890 
1891  public:
1892   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1893   void* popframe_preserved_args();
1894   ByteSize popframe_preserved_args_size();
1895   WordSize popframe_preserved_args_size_in_words();
1896   void  popframe_free_preserved_args();
1897 
1898 
1899  private:
1900   JvmtiThreadState *_jvmti_thread_state;
1901   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1902 
1903   // Used by the interpreter in fullspeed mode for frame pop, method
1904   // entry, method exit and single stepping support. This field is
1905   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1906   // It can be set to zero asynchronously (i.e., without a VM operation
1907   // or a lock) so we have to be very careful.
1908   int               _interp_only_mode;
1909 
1910  public:
1911   // used by the interpreter for fullspeed debugging support (see above)
1912   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1913   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1914   int get_interp_only_mode()                { return _interp_only_mode; }
1915   void increment_interp_only_mode()         { ++_interp_only_mode; }
1916   void decrement_interp_only_mode()         { --_interp_only_mode; }
1917 
1918   // support for cached flag that indicates whether exceptions need to be posted for this thread
1919   // if this is false, we can avoid deoptimizing when events are thrown
1920   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1921  private:
1922   int    _should_post_on_exceptions_flag;
1923 
1924  public:
1925   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1926   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1927 
1928  private:
1929   ThreadStatistics *_thread_stat;
1930 
1931  public:
1932   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1933 
1934   // Return a blocker object for which this thread is blocked parking.
1935   oop current_park_blocker();
1936 
1937  private:
1938   static size_t _stack_size_at_create;
1939 
1940  public:
1941   static inline size_t stack_size_at_create(void) {
1942     return _stack_size_at_create;
1943   }
1944   static inline void set_stack_size_at_create(size_t value) {
1945     _stack_size_at_create = value;
1946   }
1947 
1948   // Machine dependent stuff
1949 #include OS_CPU_HEADER(thread)
1950 
1951  public:
1952   void set_blocked_on_compilation(bool value) {
1953     _blocked_on_compilation = value;
1954   }
1955 
1956   bool blocked_on_compilation() {
1957     return _blocked_on_compilation;
1958   }
1959  protected:
1960   bool         _blocked_on_compilation;
1961 
1962 
1963   // JSR166 per-thread parker
1964  private:
1965   Parker*    _parker;
1966  public:
1967   Parker*     parker() { return _parker; }
1968 
1969   // Biased locking support
1970  private:
1971   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1972  public:
1973   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1974   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1975 
1976   // clearing/querying jni attach status
1977   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1978   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1979   inline void set_done_attaching_via_jni();
1980 };
1981 
1982 // Inline implementation of JavaThread::current
1983 inline JavaThread* JavaThread::current() {
1984   Thread* thread = Thread::current();
1985   assert(thread->is_Java_thread(), "just checking");
1986   return (JavaThread*)thread;
1987 }
1988 
1989 inline CompilerThread* JavaThread::as_CompilerThread() {
1990   assert(is_Compiler_thread(), "just checking");
1991   return (CompilerThread*)this;
1992 }
1993 
1994 // Dedicated thread to sweep the code cache
1995 class CodeCacheSweeperThread : public JavaThread {
1996   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
1997  public:
1998   CodeCacheSweeperThread();
1999   // Track the nmethod currently being scanned by the sweeper
2000   void set_scanned_compiled_method(CompiledMethod* cm) {
2001     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2002     _scanned_compiled_method = cm;
2003   }
2004 
2005   // Hide sweeper thread from external view.
2006   bool is_hidden_from_external_view() const { return true; }
2007 
2008   bool is_Code_cache_sweeper_thread() const { return true; }
2009 
2010   // Prevent GC from unloading _scanned_compiled_method
2011   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2012   void nmethods_do(CodeBlobClosure* cf);
2013 };
2014 
2015 // A thread used for Compilation.
2016 class CompilerThread : public JavaThread {
2017   friend class VMStructs;
2018  private:
2019   CompilerCounters* _counters;
2020 
2021   ciEnv*                _env;
2022   CompileLog*           _log;
2023   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2024   CompileQueue*         _queue;
2025   BufferBlob*           _buffer_blob;
2026 
2027   AbstractCompiler*     _compiler;
2028   TimeStamp             _idle_time;
2029 
2030  public:
2031 
2032   static CompilerThread* current();
2033 
2034   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2035   ~CompilerThread();
2036 
2037   bool is_Compiler_thread() const                { return true; }
2038 
2039   virtual bool can_call_java() const;
2040 
2041   // Hide native compiler threads from external view.
2042   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2043 
2044   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2045   AbstractCompiler* compiler() const             { return _compiler; }
2046 
2047   CompileQueue* queue()        const             { return _queue; }
2048   CompilerCounters* counters() const             { return _counters; }
2049 
2050   // Get/set the thread's compilation environment.
2051   ciEnv*        env()                            { return _env; }
2052   void          set_env(ciEnv* env)              { _env = env; }
2053 
2054   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2055   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2056 
2057   // Get/set the thread's logging information
2058   CompileLog*   log()                            { return _log; }
2059   void          init_log(CompileLog* log) {
2060     // Set once, for good.
2061     assert(_log == NULL, "set only once");
2062     _log = log;
2063   }
2064 
2065   void start_idle_timer()                        { _idle_time.update(); }
2066   jlong idle_time_millis() {
2067     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2068   }
2069 
2070 #ifndef PRODUCT
2071  private:
2072   IdealGraphPrinter *_ideal_graph_printer;
2073  public:
2074   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2075   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2076 #endif
2077 
2078   // Get/set the thread's current task
2079   CompileTask* task()                      { return _task; }
2080   void         set_task(CompileTask* task) { _task = task; }
2081 };
2082 
2083 inline CompilerThread* CompilerThread::current() {
2084   return JavaThread::current()->as_CompilerThread();
2085 }
2086 
2087 // The active thread queue. It also keeps track of the current used
2088 // thread priorities.
2089 class Threads: AllStatic {
2090   friend class VMStructs;
2091  private:
2092   static JavaThread* _thread_list;
2093   static int         _number_of_threads;
2094   static int         _number_of_non_daemon_threads;
2095   static int         _return_code;
2096   static int         _thread_claim_parity;
2097 #ifdef ASSERT
2098   static bool        _vm_complete;
2099 #endif
2100 
2101   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2102   static void initialize_jsr292_core_classes(TRAPS);
2103 
2104  public:
2105   // Thread management
2106   // force_daemon is a concession to JNI, where we may need to add a
2107   // thread to the thread list before allocating its thread object
2108   static void add(JavaThread* p, bool force_daemon = false);
2109   static void remove(JavaThread* p);
2110   static void non_java_threads_do(ThreadClosure* tc);
2111   static void java_threads_do(ThreadClosure* tc);
2112   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2113   static void threads_do(ThreadClosure* tc);
2114   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2115 
2116   // Initializes the vm and creates the vm thread
2117   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2118   static void convert_vm_init_libraries_to_agents();
2119   static void create_vm_init_libraries();
2120   static void create_vm_init_agents();
2121   static void shutdown_vm_agents();
2122   static bool destroy_vm();
2123   // Supported VM versions via JNI
2124   // Includes JNI_VERSION_1_1
2125   static jboolean is_supported_jni_version_including_1_1(jint version);
2126   // Does not include JNI_VERSION_1_1
2127   static jboolean is_supported_jni_version(jint version);
2128 
2129   // The "thread claim parity" provides a way for threads to be claimed
2130   // by parallel worker tasks.
2131   //
2132   // Each thread contains a a "parity" field. A task will claim the
2133   // thread only if its parity field is the same as the global parity,
2134   // which is updated by calling change_thread_claim_parity().
2135   //
2136   // For this to work change_thread_claim_parity() needs to be called
2137   // exactly once in sequential code before starting parallel tasks
2138   // that should claim threads.
2139   //
2140   // New threads get their parity set to 0 and change_thread_claim_parity()
2141   // never set the global parity to 0.
2142   static int thread_claim_parity() { return _thread_claim_parity; }
2143   static void change_thread_claim_parity();
2144   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2145 
2146   // Apply "f->do_oop" to all root oops in all threads.
2147   // This version may only be called by sequential code.
2148   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2149   // This version may be called by sequential or parallel code.
2150   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2151 
2152   // Apply "f->do_oop" to roots in all threads that
2153   // are part of compiled frames
2154   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2155 
2156   static void convert_hcode_pointers();
2157   static void restore_hcode_pointers();
2158 
2159   // Sweeper
2160   static void nmethods_do(CodeBlobClosure* cf);
2161 
2162   // RedefineClasses support
2163   static void metadata_do(void f(Metadata*));
2164   static void metadata_handles_do(void f(Metadata*));
2165 
2166 #ifdef ASSERT
2167   static bool is_vm_complete() { return _vm_complete; }
2168 #endif
2169 
2170   // Verification
2171   static void verify();
2172   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
2173   static void print(bool print_stacks, bool internal_format) {
2174     // this function is only used by debug.cpp
2175     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
2176   }
2177   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2178   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2179                              int buflen, bool* found_current);
2180   static void print_threads_compiling(outputStream* st, char* buf, int buflen);
2181 
2182   // Get Java threads that are waiting to enter a monitor.
2183   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2184                                                          int count, address monitor);
2185 
2186   // Get owning Java thread from the monitor's owner field.
2187   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2188                                                       address owner);
2189 
2190   // Number of threads on the active threads list
2191   static int number_of_threads()                 { return _number_of_threads; }
2192   // Number of non-daemon threads on the active threads list
2193   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2194 
2195   // Deoptimizes all frames tied to marked nmethods
2196   static void deoptimized_wrt_marked_nmethods();
2197 };
2198 
2199 
2200 // Thread iterator
2201 class ThreadClosure: public StackObj {
2202  public:
2203   virtual void do_thread(Thread* thread) = 0;
2204 };
2205 
2206 class SignalHandlerMark: public StackObj {
2207  private:
2208   Thread* _thread;
2209  public:
2210   SignalHandlerMark(Thread* t) {
2211     _thread = t;
2212     if (_thread) _thread->enter_signal_handler();
2213   }
2214   ~SignalHandlerMark() {
2215     if (_thread) _thread->leave_signal_handler();
2216     _thread = NULL;
2217   }
2218 };
2219 
2220 
2221 #endif // SHARE_VM_RUNTIME_THREAD_HPP
--- EOF ---