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/threadLocalAllocBuffer.hpp"
  30 #include "memory/allocation.hpp"
  31 #include "oops/oop.hpp"
  32 #include "prims/jvmtiExport.hpp"
  33 #include "runtime/frame.hpp"
  34 #include "runtime/handshake.hpp"
  35 #include "runtime/javaFrameAnchor.hpp"
  36 #include "runtime/jniHandles.hpp"
  37 #include "runtime/mutexLocker.hpp"
  38 #include "runtime/os.hpp"
  39 #include "runtime/osThread.hpp"
  40 #include "runtime/park.hpp"
  41 #include "runtime/safepoint.hpp"
  42 #include "runtime/stubRoutines.hpp"
  43 #include "runtime/threadLocalStorage.hpp"
  44 #include "runtime/unhandledOops.hpp"
  45 #include "trace/traceBackend.hpp"
  46 #include "trace/traceMacros.hpp"
  47 #include "utilities/align.hpp"
  48 #include "utilities/exceptions.hpp"
  49 #include "utilities/macros.hpp"
  50 #if INCLUDE_ALL_GCS
  51 #include "gc/g1/dirtyCardQueue.hpp"
  52 #include "gc/g1/satbMarkQueue.hpp"
  53 #endif // INCLUDE_ALL_GCS
  54 #ifdef ZERO
  55 # include "stack_zero.hpp"
  56 #endif
  57 
  58 class ThreadSafepointState;
  59 class ThreadsList;
  60 class ThreadsSMRSupport;
  61 class NestedThreadsList;
  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   // Exception handling
 116   // (Note: _pending_exception and friends are in ThreadShadow)
 117   //oop       _pending_exception;                // pending exception for current thread
 118   // const char* _exception_file;                   // file information for exception (debugging only)
 119   // int         _exception_line;                   // line information for exception (debugging only)
 120  protected:
 121   // Support for forcing alignment of thread objects for biased locking
 122   void*       _real_malloc_address;
 123 
 124   // JavaThread lifecycle support:
 125   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 126   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_nested_threads_hazard_ptr(), get_threads_hazard_ptr(), untag_hazard_ptr() access
 127   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 128   friend class ThreadsListSetter;  // for get_threads_hazard_ptr() access
 129   friend class ThreadsSMRSupport;  // for get_threads_hazard_ptr() access
 130 
 131   ThreadsList* volatile _threads_hazard_ptr;
 132   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 133   ThreadsList*          get_threads_hazard_ptr();
 134   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 135   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 136     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 137   }
 138   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 139     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 140   }
 141   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 142     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 143   }
 144   NestedThreadsList* _nested_threads_hazard_ptr;
 145   NestedThreadsList* get_nested_threads_hazard_ptr() {
 146     return _nested_threads_hazard_ptr;
 147   }
 148   void set_nested_threads_hazard_ptr(NestedThreadsList* value) {
 149     assert(Threads_lock->owned_by_self(),
 150            "must own Threads_lock for _nested_threads_hazard_ptr to be valid.");
 151     _nested_threads_hazard_ptr = value;
 152   }
 153   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 154   uint _nested_threads_hazard_ptr_cnt;
 155   void dec_nested_threads_hazard_ptr_cnt() {
 156     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 157     _nested_threads_hazard_ptr_cnt--;
 158   }
 159   void inc_nested_threads_hazard_ptr_cnt() {
 160     _nested_threads_hazard_ptr_cnt++;
 161   }
 162   uint nested_threads_hazard_ptr_cnt() {
 163     return _nested_threads_hazard_ptr_cnt;
 164   }
 165 
 166  public:
 167   void* operator new(size_t size) throw() { return allocate(size, true); }
 168   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 169     return allocate(size, false); }
 170   void  operator delete(void* p);
 171 
 172  protected:
 173   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 174  private:
 175 
 176   // ***************************************************************
 177   // Suspend and resume support
 178   // ***************************************************************
 179   //
 180   // VM suspend/resume no longer exists - it was once used for various
 181   // things including safepoints but was deprecated and finally removed
 182   // in Java 7. Because VM suspension was considered "internal" Java-level
 183   // suspension was considered "external", and this legacy naming scheme
 184   // remains.
 185   //
 186   // External suspend/resume requests come from JVM_SuspendThread,
 187   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 188   // ResumeThread. External
 189   // suspend requests cause _external_suspend to be set and external
 190   // resume requests cause _external_suspend to be cleared.
 191   // External suspend requests do not nest on top of other external
 192   // suspend requests. The higher level APIs reject suspend requests
 193   // for already suspended threads.
 194   //
 195   // The external_suspend
 196   // flag is checked by has_special_runtime_exit_condition() and java thread
 197   // will self-suspend when handle_special_runtime_exit_condition() is
 198   // called. Most uses of the _thread_blocked state in JavaThreads are
 199   // considered the same as being externally suspended; if the blocking
 200   // condition lifts, the JavaThread will self-suspend. Other places
 201   // where VM checks for external_suspend include:
 202   //   + mutex granting (do not enter monitors when thread is suspended)
 203   //   + state transitions from _thread_in_native
 204   //
 205   // In general, java_suspend() does not wait for an external suspend
 206   // request to complete. When it returns, the only guarantee is that
 207   // the _external_suspend field is true.
 208   //
 209   // wait_for_ext_suspend_completion() is used to wait for an external
 210   // suspend request to complete. External suspend requests are usually
 211   // followed by some other interface call that requires the thread to
 212   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 213   // the interface that requires quiescence, we give the JavaThread a
 214   // chance to self-suspend before we need it to be quiescent. This
 215   // improves overall suspend/query performance.
 216   //
 217   // _suspend_flags controls the behavior of java_ suspend/resume.
 218   // It must be set under the protection of SR_lock. Read from the flag is
 219   // OK without SR_lock as long as the value is only used as a hint.
 220   // (e.g., check _external_suspend first without lock and then recheck
 221   // inside SR_lock and finish the suspension)
 222   //
 223   // _suspend_flags is also overloaded for other "special conditions" so
 224   // that a single check indicates whether any special action is needed
 225   // eg. for async exceptions.
 226   // -------------------------------------------------------------------
 227   // Notes:
 228   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 229   // but we still update its value to keep other part of the system (mainly
 230   // JVMTI) happy. ThreadState is legacy code (see notes in
 231   // osThread.hpp).
 232   //
 233   // 2. It would be more natural if set_external_suspend() is private and
 234   // part of java_suspend(), but that probably would affect the suspend/query
 235   // performance. Need more investigation on this.
 236 
 237   // suspend/resume lock: used for self-suspend
 238   Monitor* _SR_lock;
 239 
 240  protected:
 241   enum SuspendFlags {
 242     // NOTE: avoid using the sign-bit as cc generates different test code
 243     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 244 
 245     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 246     _ext_suspended          = 0x40000000U, // thread has self-suspended
 247     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 248 
 249     _has_async_exception    = 0x00000001U, // there is a pending async exception
 250     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 251 
 252     _trace_flag             = 0x00000004U  // call tracing backend
 253   };
 254 
 255   // various suspension related flags - atomically updated
 256   // overloaded for async exception checking in check_special_condition_for_native_trans.
 257   volatile uint32_t _suspend_flags;
 258 
 259  private:
 260   int _num_nested_signal;
 261 
 262   DEBUG_ONLY(bool _suspendible_thread;)
 263 
 264  public:
 265   void enter_signal_handler() { _num_nested_signal++; }
 266   void leave_signal_handler() { _num_nested_signal--; }
 267   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 268 
 269 #ifdef ASSERT
 270   void set_suspendible_thread() {
 271     _suspendible_thread = true;
 272   }
 273 
 274   void clear_suspendible_thread() {
 275     _suspendible_thread = false;
 276   }
 277 
 278   bool is_suspendible_thread() { return _suspendible_thread; }
 279 #endif
 280 
 281  private:
 282   // Active_handles points to a block of handles
 283   JNIHandleBlock* _active_handles;
 284 
 285   // One-element thread local free list
 286   JNIHandleBlock* _free_handle_block;
 287 
 288   // Point to the last handle mark
 289   HandleMark* _last_handle_mark;
 290 
 291   // The parity of the last strong_roots iteration in which this thread was
 292   // claimed as a task.
 293   int _oops_do_parity;
 294 
 295  public:
 296   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 297   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 298  private:
 299 
 300   // debug support for checking if code does allow safepoints or not
 301   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 302   // mutex, or blocking on an object synchronizer (Java locking).
 303   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 304   // If !allow_allocation(), then an assertion failure will happen during allocation
 305   // (Hence, !allow_safepoint() => !allow_allocation()).
 306   //
 307   // The two classes NoSafepointVerifier and No_Allocation_Verifier are used to set these counters.
 308   //
 309   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 310   debug_only(int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 311 
 312   // Used by SkipGCALot class.
 313   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 314 
 315   friend class NoAllocVerifier;
 316   friend class NoSafepointVerifier;
 317   friend class PauseNoSafepointVerifier;
 318   friend class GCLocker;
 319 
 320   volatile void* _polling_page;                 // Thread local polling page
 321 
 322   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 323   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 324                                                 // the Java heap
 325 
 326   mutable TRACE_DATA _trace_data;               // Thread-local data for tracing
 327 
 328   int   _vm_operation_started_count;            // VM_Operation support
 329   int   _vm_operation_completed_count;          // VM_Operation support
 330 
 331   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 332                                                 // is waiting to lock
 333   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 334 
 335   // ObjectMonitor on which this thread called Object.wait()
 336   ObjectMonitor* _current_waiting_monitor;
 337 
 338   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 339  public:
 340   ObjectMonitor* omFreeList;
 341   int omFreeCount;                              // length of omFreeList
 342   int omFreeProvision;                          // reload chunk size
 343   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 344   int omInUseCount;                             // length of omInUseList
 345 
 346 #ifdef ASSERT
 347  private:
 348   bool _visited_for_critical_count;
 349 
 350  public:
 351   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 352   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 353 #endif
 354 
 355  public:
 356   enum {
 357     is_definitely_current_thread = true
 358   };
 359 
 360   // Constructor
 361   Thread();
 362   virtual ~Thread();
 363 
 364   // Manage Thread::current()
 365   void initialize_thread_current();
 366   void clear_thread_current(); // TLS cleanup needed before threads terminate
 367 
 368   public:
 369   // thread entry point
 370   virtual void run();
 371 
 372   // Testers
 373   virtual bool is_VM_thread()       const            { return false; }
 374   virtual bool is_Java_thread()     const            { return false; }
 375   virtual bool is_Compiler_thread() const            { return false; }
 376   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 377   virtual bool is_hidden_from_external_view() const  { return false; }
 378   virtual bool is_jvmti_agent_thread() const         { return false; }
 379   // True iff the thread can perform GC operations at a safepoint.
 380   // Generally will be true only of VM thread and parallel GC WorkGang
 381   // threads.
 382   virtual bool is_GC_task_thread() const             { return false; }
 383   virtual bool is_Watcher_thread() const             { return false; }
 384   virtual bool is_ConcurrentGC_thread() const        { return false; }
 385   virtual bool is_Named_thread() const               { return false; }
 386   virtual bool is_Worker_thread() const              { return false; }
 387 
 388   // Can this thread make Java upcalls
 389   virtual bool can_call_java() const                 { return false; }
 390 
 391   // Casts
 392   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 393 
 394   virtual char* name() const { return (char*)"Unknown thread"; }
 395 
 396   // Returns the current thread (ASSERTS if NULL)
 397   static inline Thread* current();
 398   // Returns the current thread, or NULL if not attached
 399   static inline Thread* current_or_null();
 400   // Returns the current thread, or NULL if not attached, and is
 401   // safe for use from signal-handlers
 402   static inline Thread* current_or_null_safe();
 403 
 404   // Common thread operations
 405 #ifdef ASSERT
 406   static void check_for_dangling_thread_pointer(Thread *thread);
 407 #endif
 408   static void set_priority(Thread* thread, ThreadPriority priority);
 409   static ThreadPriority get_priority(const Thread* const thread);
 410   static void start(Thread* thread);
 411   static void interrupt(Thread* thr);
 412   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 413 
 414   void set_native_thread_name(const char *name) {
 415     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 416     os::set_native_thread_name(name);
 417   }
 418 
 419   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 420   Monitor* SR_lock() const                       { return _SR_lock; }
 421 
 422   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 423 
 424   inline void set_suspend_flag(SuspendFlags f);
 425   inline void clear_suspend_flag(SuspendFlags f);
 426 
 427   inline void set_has_async_exception();
 428   inline void clear_has_async_exception();
 429 
 430   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 431 
 432   inline void set_critical_native_unlock();
 433   inline void clear_critical_native_unlock();
 434 
 435   inline void set_trace_flag();
 436   inline void clear_trace_flag();
 437 
 438   // Support for Unhandled Oop detection
 439   // Add the field for both, fastdebug and debug, builds to keep
 440   // Thread's fields layout the same.
 441   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 442 #ifdef CHECK_UNHANDLED_OOPS
 443  private:
 444   UnhandledOops* _unhandled_oops;
 445 #elif defined(ASSERT)
 446  private:
 447   void* _unhandled_oops;
 448 #endif
 449 #ifdef CHECK_UNHANDLED_OOPS
 450  public:
 451   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 452   // Mark oop safe for gc.  It may be stack allocated but won't move.
 453   void allow_unhandled_oop(oop *op) {
 454     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 455   }
 456   // Clear oops at safepoint so crashes point to unhandled oop violator
 457   void clear_unhandled_oops() {
 458     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 459   }
 460 #endif // CHECK_UNHANDLED_OOPS
 461 
 462  public:
 463 #ifndef PRODUCT
 464   bool skip_gcalot()           { return _skip_gcalot; }
 465   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 466 #endif
 467 
 468   // Installs a pending exception to be inserted later
 469   static void send_async_exception(oop thread_oop, oop java_throwable);
 470 
 471   // Resource area
 472   ResourceArea* resource_area() const            { return _resource_area; }
 473   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 474 
 475   OSThread* osthread() const                     { return _osthread;   }
 476   void set_osthread(OSThread* thread)            { _osthread = thread; }
 477 
 478   // JNI handle support
 479   JNIHandleBlock* active_handles() const         { return _active_handles; }
 480   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 481   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 482   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 483 
 484   // Internal handle support
 485   HandleArea* handle_area() const                { return _handle_area; }
 486   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 487 
 488   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 489   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 490 
 491   // Thread-Local Allocation Buffer (TLAB) support
 492   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 493   void initialize_tlab() {
 494     if (UseTLAB) {
 495       tlab().initialize();
 496     }
 497   }
 498 
 499   jlong allocated_bytes()               { return _allocated_bytes; }
 500   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 501   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 502   inline jlong cooked_allocated_bytes();
 503 
 504   TRACE_DEFINE_THREAD_TRACE_DATA_OFFSET;
 505   TRACE_DATA* trace_data() const        { return &_trace_data; }
 506   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 507 
 508   // VM operation support
 509   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 510   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 511   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 512 
 513   // For tracking the heavyweight monitor the thread is pending on.
 514   ObjectMonitor* current_pending_monitor() {
 515     return _current_pending_monitor;
 516   }
 517   void set_current_pending_monitor(ObjectMonitor* monitor) {
 518     _current_pending_monitor = monitor;
 519   }
 520   void set_current_pending_monitor_is_from_java(bool from_java) {
 521     _current_pending_monitor_is_from_java = from_java;
 522   }
 523   bool current_pending_monitor_is_from_java() {
 524     return _current_pending_monitor_is_from_java;
 525   }
 526 
 527   // For tracking the ObjectMonitor on which this thread called Object.wait()
 528   ObjectMonitor* current_waiting_monitor() {
 529     return _current_waiting_monitor;
 530   }
 531   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 532     _current_waiting_monitor = monitor;
 533   }
 534 
 535   // GC support
 536   // Apply "f->do_oop" to all root oops in "this".
 537   //   Used by JavaThread::oops_do.
 538   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 539   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 540 
 541   // Handles the parallel case for the method below.
 542  private:
 543   bool claim_oops_do_par_case(int collection_parity);
 544  public:
 545   // Requires that "collection_parity" is that of the current roots
 546   // iteration.  If "is_par" is false, sets the parity of "this" to
 547   // "collection_parity", and returns "true".  If "is_par" is true,
 548   // uses an atomic instruction to set the current threads parity to
 549   // "collection_parity", if it is not already.  Returns "true" iff the
 550   // calling thread does the update, this indicates that the calling thread
 551   // has claimed the thread's stack as a root groop in the current
 552   // collection.
 553   bool claim_oops_do(bool is_par, int collection_parity) {
 554     if (!is_par) {
 555       _oops_do_parity = collection_parity;
 556       return true;
 557     } else {
 558       return claim_oops_do_par_case(collection_parity);
 559     }
 560   }
 561 
 562   // jvmtiRedefineClasses support
 563   void metadata_handles_do(void f(Metadata*));
 564 
 565   // Used by fast lock support
 566   virtual bool is_lock_owned(address adr) const;
 567 
 568   // Check if address is in the stack of the thread (not just for locks).
 569   // Warning: the method can only be used on the running thread
 570   bool is_in_stack(address adr) const;
 571   // Check if address is in the usable part of the stack (excludes protected
 572   // guard pages)
 573   bool is_in_usable_stack(address adr) const;
 574 
 575   // Sets this thread as starting thread. Returns failure if thread
 576   // creation fails due to lack of memory, too many threads etc.
 577   bool set_as_starting_thread();
 578 
 579 protected:
 580   // OS data associated with the thread
 581   OSThread* _osthread;  // Platform-specific thread information
 582 
 583   // Thread local resource area for temporary allocation within the VM
 584   ResourceArea* _resource_area;
 585 
 586   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 587 
 588   // Thread local handle area for allocation of handles within the VM
 589   HandleArea* _handle_area;
 590   GrowableArray<Metadata*>* _metadata_handles;
 591 
 592   // Support for stack overflow handling, get_thread, etc.
 593   address          _stack_base;
 594   size_t           _stack_size;
 595   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 596   int              _lgrp_id;
 597 
 598   volatile void** polling_page_addr() { return &_polling_page; }
 599 
 600  public:
 601   // Stack overflow support
 602   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 603   void    set_stack_base(address base) { _stack_base = base; }
 604   size_t  stack_size() const           { return _stack_size; }
 605   void    set_stack_size(size_t size)  { _stack_size = size; }
 606   address stack_end()  const           { return stack_base() - stack_size(); }
 607   void    record_stack_base_and_size();
 608 
 609   bool    on_local_stack(address adr) const {
 610     // QQQ this has knowledge of direction, ought to be a stack method
 611     return (_stack_base >= adr && adr >= stack_end());
 612   }
 613 
 614   uintptr_t self_raw_id()                    { return _self_raw_id; }
 615   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 616 
 617   int     lgrp_id() const        { return _lgrp_id; }
 618   void    set_lgrp_id(int value) { _lgrp_id = value; }
 619 
 620   // Printing
 621   virtual void print_on(outputStream* st) const;
 622   virtual void print_nested_threads_hazard_ptrs_on(outputStream* st) const;
 623   void print() const { print_on(tty); }
 624   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 625   void print_value_on(outputStream* st) const;
 626 
 627   // Debug-only code
 628 #ifdef ASSERT
 629  private:
 630   // Deadlock detection support for Mutex locks. List of locks own by thread.
 631   Monitor* _owned_locks;
 632   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 633   // thus the friendship
 634   friend class Mutex;
 635   friend class Monitor;
 636 
 637  public:
 638   void print_owned_locks_on(outputStream* st) const;
 639   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 640   Monitor* owned_locks() const                   { return _owned_locks;          }
 641   bool owns_locks() const                        { return owned_locks() != NULL; }
 642   bool owns_locks_but_compiled_lock() const;
 643   int oops_do_parity() const                     { return _oops_do_parity; }
 644 
 645   // Deadlock detection
 646   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 647   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 648   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 649 #endif
 650 
 651   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 652 
 653  private:
 654   volatile int _jvmti_env_iteration_count;
 655 
 656  public:
 657   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 658   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 659   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 660 
 661   // Code generation
 662   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 663   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 664   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 665 
 666   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 667   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 668 
 669   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 670 
 671 #define TLAB_FIELD_OFFSET(name) \
 672   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 673 
 674   TLAB_FIELD_OFFSET(start)
 675   TLAB_FIELD_OFFSET(end)
 676   TLAB_FIELD_OFFSET(top)
 677   TLAB_FIELD_OFFSET(pf_top)
 678   TLAB_FIELD_OFFSET(size)                   // desired_size
 679   TLAB_FIELD_OFFSET(refill_waste_limit)
 680   TLAB_FIELD_OFFSET(number_of_refills)
 681   TLAB_FIELD_OFFSET(fast_refill_waste)
 682   TLAB_FIELD_OFFSET(slow_allocations)
 683 
 684 #undef TLAB_FIELD_OFFSET
 685 
 686   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 687 
 688  public:
 689   volatile intptr_t _Stalled;
 690   volatile int _TypeTag;
 691   ParkEvent * _ParkEvent;                     // for synchronized()
 692   ParkEvent * _SleepEvent;                    // for Thread.sleep
 693   ParkEvent * _MutexEvent;                    // for native internal Mutex/Monitor
 694   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 695   int NativeSyncRecursion;                    // diagnostic
 696 
 697   volatile int _OnTrap;                       // Resume-at IP delta
 698   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 699   jint _hashStateX;                           // thread-specific hashCode generator state
 700   jint _hashStateY;
 701   jint _hashStateZ;
 702   void * _schedctl;
 703 
 704 
 705   volatile jint rng[4];                      // RNG for spin loop
 706 
 707   // Low-level leaf-lock primitives used to implement synchronization
 708   // and native monitor-mutex infrastructure.
 709   // Not for general synchronization use.
 710   static void SpinAcquire(volatile int * Lock, const char * Name);
 711   static void SpinRelease(volatile int * Lock);
 712   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 713   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 714   static void muxRelease(volatile intptr_t * Lock);
 715 };
 716 
 717 // Inline implementation of Thread::current()
 718 inline Thread* Thread::current() {
 719   Thread* current = current_or_null();
 720   assert(current != NULL, "Thread::current() called on detached thread");
 721   return current;
 722 }
 723 
 724 inline Thread* Thread::current_or_null() {
 725 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 726   return _thr_current;
 727 #else
 728   if (ThreadLocalStorage::is_initialized()) {
 729     return ThreadLocalStorage::thread();
 730   }
 731   return NULL;
 732 #endif
 733 }
 734 
 735 inline Thread* Thread::current_or_null_safe() {
 736   if (ThreadLocalStorage::is_initialized()) {
 737     return ThreadLocalStorage::thread();
 738   }
 739   return NULL;
 740 }
 741 
 742 // Name support for threads.  non-JavaThread subclasses with multiple
 743 // uniquely named instances should derive from this.
 744 class NamedThread: public Thread {
 745   friend class VMStructs;
 746   enum {
 747     max_name_len = 64
 748   };
 749  private:
 750   char* _name;
 751   // log JavaThread being processed by oops_do
 752   JavaThread* _processed_thread;
 753   uint _gc_id; // The current GC id when a thread takes part in GC
 754 
 755  public:
 756   NamedThread();
 757   ~NamedThread();
 758   // May only be called once per thread.
 759   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 760   void initialize_named_thread();
 761   virtual bool is_Named_thread() const { return true; }
 762   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 763   JavaThread *processed_thread() { return _processed_thread; }
 764   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 765   virtual void print_on(outputStream* st) const;
 766 
 767   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 768   uint gc_id() { return _gc_id; }
 769 };
 770 
 771 // Worker threads are named and have an id of an assigned work.
 772 class WorkerThread: public NamedThread {
 773  private:
 774   uint _id;
 775  public:
 776   WorkerThread() : _id(0)               { }
 777   virtual bool is_Worker_thread() const { return true; }
 778 
 779   virtual WorkerThread* as_Worker_thread() const {
 780     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 781     return (WorkerThread*) this;
 782   }
 783 
 784   void set_id(uint work_id)             { _id = work_id; }
 785   uint id() const                       { return _id; }
 786 };
 787 
 788 // A single WatcherThread is used for simulating timer interrupts.
 789 class WatcherThread: public Thread {
 790   friend class VMStructs;
 791  public:
 792   virtual void run();
 793 
 794  private:
 795   static WatcherThread* _watcher_thread;
 796 
 797   static bool _startable;
 798   // volatile due to at least one lock-free read
 799   volatile static bool _should_terminate;
 800  public:
 801   enum SomeConstants {
 802     delay_interval = 10                          // interrupt delay in milliseconds
 803   };
 804 
 805   // Constructor
 806   WatcherThread();
 807 
 808   // No destruction allowed
 809   ~WatcherThread() {
 810     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 811   }
 812 
 813   // Tester
 814   bool is_Watcher_thread() const                 { return true; }
 815 
 816   // Printing
 817   char* name() const { return (char*)"VM Periodic Task Thread"; }
 818   void print_on(outputStream* st) const;
 819   void unpark();
 820 
 821   // Returns the single instance of WatcherThread
 822   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 823 
 824   // Create and start the single instance of WatcherThread, or stop it on shutdown
 825   static void start();
 826   static void stop();
 827   // Only allow start once the VM is sufficiently initialized
 828   // Otherwise the first task to enroll will trigger the start
 829   static void make_startable();
 830  private:
 831   int sleep() const;
 832 };
 833 
 834 
 835 class CompilerThread;
 836 
 837 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 838 
 839 class JavaThread: public Thread {
 840   friend class VMStructs;
 841   friend class JVMCIVMStructs;
 842   friend class WhiteBox;
 843  private:
 844   JavaThread*    _next;                          // The next thread in the Threads list
 845   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 846   oop            _threadObj;                     // The Java level thread object
 847 
 848 #ifdef ASSERT
 849  private:
 850   int _java_call_counter;
 851 
 852  public:
 853   int  java_call_counter()                       { return _java_call_counter; }
 854   void inc_java_call_counter()                   { _java_call_counter++; }
 855   void dec_java_call_counter() {
 856     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 857     _java_call_counter--;
 858   }
 859  private:  // restore original namespace restriction
 860 #endif  // ifdef ASSERT
 861 
 862 #ifndef PRODUCT
 863  public:
 864   enum {
 865     jump_ring_buffer_size = 16
 866   };
 867  private:  // restore original namespace restriction
 868 #endif
 869 
 870   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 871 
 872   ThreadFunction _entry_point;
 873 
 874   JNIEnv        _jni_environment;
 875 
 876   // Deopt support
 877   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 878 
 879   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 880                                                  // transition out of native
 881   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
 882   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 883   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 884   // Because deoptimization is lazy we must save jvmti requests to set locals
 885   // in compiled frames until we deoptimize and we have an interpreter frame.
 886   // This holds the pointer to array (yeah like there might be more than one) of
 887   // description of compiled vframes that have locals that need to be updated.
 888   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 889 
 890   // Handshake value for fixing 6243940. We need a place for the i2c
 891   // adapter to store the callee Method*. This value is NEVER live
 892   // across a gc point so it does NOT have to be gc'd
 893   // The handshake is open ended since we can't be certain that it will
 894   // be NULLed. This is because we rarely ever see the race and end up
 895   // in handle_wrong_method which is the backend of the handshake. See
 896   // code in i2c adapters and handle_wrong_method.
 897 
 898   Method*       _callee_target;
 899 
 900   // Used to pass back results to the interpreter or generated code running Java code.
 901   oop           _vm_result;    // oop result is GC-preserved
 902   Metadata*     _vm_result_2;  // non-oop result
 903 
 904   // See ReduceInitialCardMarks: this holds the precise space interval of
 905   // the most recent slow path allocation for which compiled code has
 906   // elided card-marks for performance along the fast-path.
 907   MemRegion     _deferred_card_mark;
 908 
 909   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 910                                                  // allocated during deoptimization
 911                                                  // and by JNI_MonitorEnter/Exit
 912 
 913   // Async. requests support
 914   enum AsyncRequests {
 915     _no_async_condition = 0,
 916     _async_exception,
 917     _async_unsafe_access_error
 918   };
 919   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 920   oop           _pending_async_exception;
 921 
 922   // Safepoint support
 923  public:                                         // Expose _thread_state for SafeFetchInt()
 924   volatile JavaThreadState _thread_state;
 925  private:
 926   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 927   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 928 
 929   // JavaThread termination support
 930   enum TerminatedTypes {
 931     _not_terminated = 0xDEAD - 2,
 932     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 933     _thread_terminated,                          // JavaThread is removed from thread list
 934     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 935                                                  // only VM_Exit can set _vm_exited
 936   };
 937 
 938   // In general a JavaThread's _terminated field transitions as follows:
 939   //
 940   //   _not_terminated => _thread_exiting => _thread_terminated
 941   //
 942   // _vm_exited is a special value to cover the case of a JavaThread
 943   // executing native code after the VM itself is terminated.
 944   volatile TerminatedTypes _terminated;
 945   // suspend/resume support
 946   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 947   jint                  _in_deopt_handler;       // count of deoptimization
 948                                                  // handlers thread is in
 949   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 950   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
 951                                                          // never locked) when throwing an exception. Used by interpreter only.
 952 
 953   // JNI attach states:
 954   enum JNIAttachStates {
 955     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 956     _attaching_via_jni,          // thread is attaching via JNI
 957     _attached_via_jni            // thread has attached via JNI
 958   };
 959 
 960   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 961   // A native thread that is attaching via JNI starts with a value
 962   // of _attaching_via_jni and transitions to _attached_via_jni.
 963   volatile JNIAttachStates _jni_attach_state;
 964 
 965  public:
 966   // State of the stack guard pages for this thread.
 967   enum StackGuardState {
 968     stack_guard_unused,         // not needed
 969     stack_guard_reserved_disabled,
 970     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
 971     stack_guard_enabled         // enabled
 972   };
 973 
 974  private:
 975 
 976 #if INCLUDE_JVMCI
 977   // The _pending_* fields below are used to communicate extra information
 978   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
 979 
 980   // Communicates the DeoptReason and DeoptAction of the uncommon trap
 981   int       _pending_deoptimization;
 982 
 983   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
 984   // before the monitor has been acquired.
 985   bool      _pending_monitorenter;
 986 
 987   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
 988   bool      _pending_transfer_to_interpreter;
 989 
 990   // Guard for re-entrant call to JVMCIRuntime::adjust_comp_level
 991   bool      _adjusting_comp_level;
 992 
 993   // An object that JVMCI compiled code can use to further describe and
 994   // uniquely identify the  speculative optimization guarded by the uncommon trap
 995   oop       _pending_failed_speculation;
 996 
 997   // These fields are mutually exclusive in terms of live ranges.
 998   union {
 999     // Communicates the pc at which the most recent implicit exception occurred
1000     // from the signal handler to a deoptimization stub.
1001     address   _implicit_exception_pc;
1002 
1003     // Communicates an alternative call target to an i2c stub from a JavaCall .
1004     address   _alternate_call_target;
1005   } _jvmci;
1006 
1007   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1008   jlong*    _jvmci_counters;
1009 
1010  public:
1011   static jlong* _jvmci_old_thread_counters;
1012   static void collect_counters(typeArrayOop array);
1013  private:
1014 #endif // INCLUDE_JVMCI
1015 
1016   StackGuardState  _stack_guard_state;
1017 
1018   // Precompute the limit of the stack as used in stack overflow checks.
1019   // We load it from here to simplify the stack overflow check in assembly.
1020   address          _stack_overflow_limit;
1021   address          _reserved_stack_activation;
1022 
1023   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1024   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1025   // code)
1026   volatile oop     _exception_oop;               // Exception thrown in compiled code
1027   volatile address _exception_pc;                // PC where exception happened
1028   volatile address _exception_handler_pc;        // PC for handler of exception
1029   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1030 
1031  private:
1032   // support for JNI critical regions
1033   jint    _jni_active_critical;                  // count of entries into JNI critical region
1034 
1035   // Checked JNI: function name requires exception check
1036   char* _pending_jni_exception_check_fn;
1037 
1038   // For deadlock detection.
1039   int _depth_first_number;
1040 
1041   // JVMTI PopFrame support
1042   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1043   int _popframe_condition;
1044 
1045   // If reallocation of scalar replaced objects fails, we throw OOM
1046   // and during exception propagation, pop the top
1047   // _frames_to_pop_failed_realloc frames, the ones that reference
1048   // failed reallocations.
1049   int _frames_to_pop_failed_realloc;
1050 
1051 #ifndef PRODUCT
1052   int _jmp_ring_index;
1053   struct {
1054     // We use intptr_t instead of address so debugger doesn't try and display strings
1055     intptr_t _target;
1056     intptr_t _instruction;
1057     const char*  _file;
1058     int _line;
1059   }   _jmp_ring[jump_ring_buffer_size];
1060 #endif // PRODUCT
1061 
1062 #if INCLUDE_ALL_GCS
1063   // Support for G1 barriers
1064 
1065   SATBMarkQueue _satb_mark_queue;        // Thread-local log for SATB barrier.


1066 
1067   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.


1068 #endif // INCLUDE_ALL_GCS
1069 
1070   friend class VMThread;
1071   friend class ThreadWaitTransition;
1072   friend class VM_Exit;
1073 
1074   void initialize();                             // Initialized the instance variables
1075 
1076  public:
1077   // Constructor
1078   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1079   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1080   ~JavaThread();
1081 
1082 #ifdef ASSERT
1083   // verify this JavaThread hasn't be published in the Threads::list yet
1084   void verify_not_published();
1085 #endif
1086 
1087   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1088   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1089     _jni_environment.functions = functionTable;
1090   }
1091   struct JNINativeInterface_* get_jni_functions() {
1092     return (struct JNINativeInterface_ *)_jni_environment.functions;
1093   }
1094 
1095   // This function is called at thread creation to allow
1096   // platform specific thread variables to be initialized.
1097   void cache_global_variables();
1098 
1099   // Executes Shutdown.shutdown()
1100   void invoke_shutdown_hooks();
1101 
1102   // Cleanup on thread exit
1103   enum ExitType {
1104     normal_exit,
1105     jni_detach
1106   };
1107   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1108 
1109   void cleanup_failed_attach_current_thread();
1110 
1111   // Testers
1112   virtual bool is_Java_thread() const            { return true;  }
1113   virtual bool can_call_java() const             { return true; }
1114 
1115   // Thread chain operations
1116   JavaThread* next() const                       { return _next; }
1117   void set_next(JavaThread* p)                   { _next = p; }
1118 
1119   // Thread oop. threadObj() can be NULL for initial JavaThread
1120   // (or for threads attached via JNI)
1121   oop threadObj() const                          { return _threadObj; }
1122   void set_threadObj(oop p)                      { _threadObj = p; }
1123 
1124   ThreadPriority java_priority() const;          // Read from threadObj()
1125 
1126   // Prepare thread and add to priority queue.  If a priority is
1127   // not specified, use the priority of the thread object. Threads_lock
1128   // must be held while this function is called.
1129   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1130 
1131   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1132   address saved_exception_pc()                   { return _saved_exception_pc; }
1133 
1134 
1135   ThreadFunction entry_point() const             { return _entry_point; }
1136 
1137   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1138   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1139 
1140   // Last frame anchor routines
1141 
1142   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1143 
1144   // last_Java_sp
1145   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1146   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1147 
1148   // last_Java_pc
1149 
1150   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1151 
1152   // Safepoint support
1153 #if !(defined(PPC64) || defined(AARCH64))
1154   JavaThreadState thread_state() const           { return _thread_state; }
1155   void set_thread_state(JavaThreadState s)       { _thread_state = s;    }
1156 #else
1157   // Use membars when accessing volatile _thread_state. See
1158   // Threads::create_vm() for size checks.
1159   inline JavaThreadState thread_state() const;
1160   inline void set_thread_state(JavaThreadState s);
1161 #endif
1162   ThreadSafepointState *safepoint_state() const  { return _safepoint_state; }
1163   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1164   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1165 
1166   // JavaThread termination and lifecycle support:
1167   void smr_delete();
1168   bool on_thread_list() const { return _on_thread_list; }
1169   void set_on_thread_list() { _on_thread_list = true; }
1170 
1171   // thread has called JavaThread::exit() or is terminated
1172   bool is_exiting() const;
1173   // thread is terminated (no longer on the threads list); we compare
1174   // against the two non-terminated values so that a freed JavaThread
1175   // will also be considered terminated.
1176   bool check_is_terminated(TerminatedTypes l_terminated) const {
1177     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1178   }
1179   bool is_terminated() const;
1180   void set_terminated(TerminatedTypes t);
1181   // special for Threads::remove() which is static:
1182   void set_terminated_value();
1183   void block_if_vm_exited();
1184 
1185   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1186   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1187 
1188   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1189   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1190 
1191   inline void set_polling_page(void* poll_value);
1192   inline volatile void* get_polling_page();
1193 
1194  private:
1195   // Support for thread handshake operations
1196   HandshakeState _handshake;
1197  public:
1198   void set_handshake_operation(HandshakeOperation* op) {
1199     _handshake.set_operation(this, op);
1200   }
1201 
1202   bool has_handshake() const {
1203     return _handshake.has_operation();
1204   }
1205 
1206   void cancel_handshake() {
1207     _handshake.cancel(this);
1208   }
1209 
1210   void handshake_process_by_self() {
1211     _handshake.process_by_self(this);
1212   }
1213 
1214   void handshake_process_by_vmthread() {
1215     _handshake.process_by_vmthread(this);
1216   }
1217 
1218   // Suspend/resume support for JavaThread
1219  private:
1220   inline void set_ext_suspended();
1221   inline void clear_ext_suspended();
1222 
1223  public:
1224   void java_suspend();
1225   void java_resume();
1226   int  java_suspend_self();
1227 
1228   void check_and_wait_while_suspended() {
1229     assert(JavaThread::current() == this, "sanity check");
1230 
1231     bool do_self_suspend;
1232     do {
1233       // were we externally suspended while we were waiting?
1234       do_self_suspend = handle_special_suspend_equivalent_condition();
1235       if (do_self_suspend) {
1236         // don't surprise the thread that suspended us by returning
1237         java_suspend_self();
1238         set_suspend_equivalent();
1239       }
1240     } while (do_self_suspend);
1241   }
1242   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1243   // Check for async exception in addition to safepoint and suspend request.
1244   static void check_special_condition_for_native_trans(JavaThread *thread);
1245 
1246   // Same as check_special_condition_for_native_trans but finishes the
1247   // transition into thread_in_Java mode so that it can potentially
1248   // block.
1249   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1250 
1251   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1252   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1253     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1254     // Warning: is_ext_suspend_completed() may temporarily drop the
1255     // SR_lock to allow the thread to reach a stable thread state if
1256     // it is currently in a transient thread state.
1257     return is_ext_suspend_completed(false /* !called_by_wait */,
1258                                     SuspendRetryDelay, bits);
1259   }
1260 
1261   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1262   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1263   // passed as the count and delay parameters. Experiments with specific
1264   // calls to wait_for_ext_suspend_completion() can be done by passing
1265   // other values in the code. Experiments with all calls can be done
1266   // via the appropriate -XX options.
1267   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1268 
1269   // test for suspend - most (all?) of these should go away
1270   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1271 
1272   inline void set_external_suspend();
1273   inline void clear_external_suspend();
1274 
1275   inline void set_deopt_suspend();
1276   inline void clear_deopt_suspend();
1277   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1278 
1279   bool is_external_suspend() const {
1280     return (_suspend_flags & _external_suspend) != 0;
1281   }
1282   // Whenever a thread transitions from native to vm/java it must suspend
1283   // if external|deopt suspend is present.
1284   bool is_suspend_after_native() const {
1285     return (_suspend_flags & (_external_suspend | _deopt_suspend)) != 0;
1286   }
1287 
1288   // external suspend request is completed
1289   bool is_ext_suspended() const {
1290     return (_suspend_flags & _ext_suspended) != 0;
1291   }
1292 
1293   bool is_external_suspend_with_lock() const {
1294     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1295     return is_external_suspend();
1296   }
1297 
1298   // Special method to handle a pending external suspend request
1299   // when a suspend equivalent condition lifts.
1300   bool handle_special_suspend_equivalent_condition() {
1301     assert(is_suspend_equivalent(),
1302            "should only be called in a suspend equivalence condition");
1303     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1304     bool ret = is_external_suspend();
1305     if (!ret) {
1306       // not about to self-suspend so clear suspend equivalence
1307       clear_suspend_equivalent();
1308     }
1309     // implied else:
1310     // We have a pending external suspend request so we leave the
1311     // suspend_equivalent flag set until java_suspend_self() sets
1312     // the ext_suspended flag and clears the suspend_equivalent
1313     // flag. This insures that wait_for_ext_suspend_completion()
1314     // will return consistent values.
1315     return ret;
1316   }
1317 
1318   // utility methods to see if we are doing some kind of suspension
1319   bool is_being_ext_suspended() const            {
1320     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1321     return is_ext_suspended() || is_external_suspend();
1322   }
1323 
1324   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1325 
1326   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1327   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1328 
1329   // Thread.stop support
1330   void send_thread_stop(oop throwable);
1331   AsyncRequests clear_special_runtime_exit_condition() {
1332     AsyncRequests x = _special_runtime_exit_condition;
1333     _special_runtime_exit_condition = _no_async_condition;
1334     return x;
1335   }
1336 
1337   // Are any async conditions present?
1338   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1339 
1340   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1341 
1342   // these next two are also used for self-suspension and async exception support
1343   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1344 
1345   // Return true if JavaThread has an asynchronous condition or
1346   // if external suspension is requested.
1347   bool has_special_runtime_exit_condition() {
1348     // Because we don't use is_external_suspend_with_lock
1349     // it is possible that we won't see an asynchronous external suspend
1350     // request that has just gotten started, i.e., SR_lock grabbed but
1351     // _external_suspend field change either not made yet or not visible
1352     // yet. However, this is okay because the request is asynchronous and
1353     // we will see the new flag value the next time through. It's also
1354     // possible that the external suspend request is dropped after
1355     // we have checked is_external_suspend(), we will recheck its value
1356     // under SR_lock in java_suspend_self().
1357     return (_special_runtime_exit_condition != _no_async_condition) ||
1358             is_external_suspend() || is_trace_suspend();
1359   }
1360 
1361   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1362 
1363   inline void set_pending_async_exception(oop e);
1364 
1365   // Fast-locking support
1366   bool is_lock_owned(address adr) const;
1367 
1368   // Accessors for vframe array top
1369   // The linked list of vframe arrays are sorted on sp. This means when we
1370   // unpack the head must contain the vframe array to unpack.
1371   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1372   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1373 
1374   // Side structure for deferring update of java frame locals until deopt occurs
1375   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1376   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1377 
1378   // These only really exist to make debugging deopt problems simpler
1379 
1380   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1381   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1382 
1383   // The special resourceMark used during deoptimization
1384 
1385   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1386   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1387 
1388   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1389   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1390   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1391 
1392   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1393   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1394 
1395   Method*    callee_target() const               { return _callee_target; }
1396   void set_callee_target  (Method* x)          { _callee_target   = x; }
1397 
1398   // Oop results of vm runtime calls
1399   oop  vm_result() const                         { return _vm_result; }
1400   void set_vm_result  (oop x)                    { _vm_result   = x; }
1401 
1402   Metadata*    vm_result_2() const               { return _vm_result_2; }
1403   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1404 
1405   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1406   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1407 
1408 #if INCLUDE_JVMCI
1409   int  pending_deoptimization() const             { return _pending_deoptimization; }
1410   oop  pending_failed_speculation() const         { return _pending_failed_speculation; }
1411   bool adjusting_comp_level() const               { return _adjusting_comp_level; }
1412   void set_adjusting_comp_level(bool b)           { _adjusting_comp_level = b; }
1413   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1414   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1415   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1416   void set_pending_failed_speculation(oop failed_speculation) { _pending_failed_speculation = failed_speculation; }
1417   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1418   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1419   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1420 #endif // INCLUDE_JVMCI
1421 
1422   // Exception handling for compiled methods
1423   oop      exception_oop() const                 { return _exception_oop; }
1424   address  exception_pc() const                  { return _exception_pc; }
1425   address  exception_handler_pc() const          { return _exception_handler_pc; }
1426   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1427 
1428   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1429   void set_exception_pc(address a)               { _exception_pc = a; }
1430   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1431   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1432 
1433   void clear_exception_oop_and_pc() {
1434     set_exception_oop(NULL);
1435     set_exception_pc(NULL);
1436   }
1437 
1438   // Stack overflow support
1439   //
1440   //  (small addresses)
1441   //
1442   //  --  <-- stack_end()                   ---
1443   //  |                                      |
1444   //  |  red pages                           |
1445   //  |                                      |
1446   //  --  <-- stack_red_zone_base()          |
1447   //  |                                      |
1448   //  |                                     guard
1449   //  |  yellow pages                       zone
1450   //  |                                      |
1451   //  |                                      |
1452   //  --  <-- stack_yellow_zone_base()       |
1453   //  |                                      |
1454   //  |                                      |
1455   //  |  reserved pages                      |
1456   //  |                                      |
1457   //  --  <-- stack_reserved_zone_base()    ---      ---
1458   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1459   //                                                  |   zone
1460   //                                                 \|/  size
1461   //  some untouched memory                          ---
1462   //
1463   //
1464   //  --
1465   //  |
1466   //  |  shadow zone
1467   //  |
1468   //  --
1469   //  x    frame n
1470   //  --
1471   //  x    frame n-1
1472   //  x
1473   //  --
1474   //  ...
1475   //
1476   //  --
1477   //  x    frame 0
1478   //  --  <-- stack_base()
1479   //
1480   //  (large addresses)
1481   //
1482 
1483  private:
1484   // These values are derived from flags StackRedPages, StackYellowPages,
1485   // StackReservedPages and StackShadowPages. The zone size is determined
1486   // ergonomically if page_size > 4K.
1487   static size_t _stack_red_zone_size;
1488   static size_t _stack_yellow_zone_size;
1489   static size_t _stack_reserved_zone_size;
1490   static size_t _stack_shadow_zone_size;
1491  public:
1492   inline size_t stack_available(address cur_sp);
1493 
1494   static size_t stack_red_zone_size() {
1495     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1496     return _stack_red_zone_size;
1497   }
1498   static void set_stack_red_zone_size(size_t s) {
1499     assert(is_aligned(s, os::vm_page_size()),
1500            "We can not protect if the red zone size is not page aligned.");
1501     assert(_stack_red_zone_size == 0, "This should be called only once.");
1502     _stack_red_zone_size = s;
1503   }
1504   address stack_red_zone_base() {
1505     return (address)(stack_end() + stack_red_zone_size());
1506   }
1507   bool in_stack_red_zone(address a) {
1508     return a <= stack_red_zone_base() && a >= stack_end();
1509   }
1510 
1511   static size_t stack_yellow_zone_size() {
1512     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1513     return _stack_yellow_zone_size;
1514   }
1515   static void set_stack_yellow_zone_size(size_t s) {
1516     assert(is_aligned(s, os::vm_page_size()),
1517            "We can not protect if the yellow zone size is not page aligned.");
1518     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1519     _stack_yellow_zone_size = s;
1520   }
1521 
1522   static size_t stack_reserved_zone_size() {
1523     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1524     return _stack_reserved_zone_size;
1525   }
1526   static void set_stack_reserved_zone_size(size_t s) {
1527     assert(is_aligned(s, os::vm_page_size()),
1528            "We can not protect if the reserved zone size is not page aligned.");
1529     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1530     _stack_reserved_zone_size = s;
1531   }
1532   address stack_reserved_zone_base() {
1533     return (address)(stack_end() +
1534                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1535   }
1536   bool in_stack_reserved_zone(address a) {
1537     return (a <= stack_reserved_zone_base()) &&
1538            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1539   }
1540 
1541   static size_t stack_yellow_reserved_zone_size() {
1542     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1543   }
1544   bool in_stack_yellow_reserved_zone(address a) {
1545     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1546   }
1547 
1548   // Size of red + yellow + reserved zones.
1549   static size_t stack_guard_zone_size() {
1550     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1551   }
1552 
1553   static size_t stack_shadow_zone_size() {
1554     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1555     return _stack_shadow_zone_size;
1556   }
1557   static void set_stack_shadow_zone_size(size_t s) {
1558     // The shadow area is not allocated or protected, so
1559     // it needs not be page aligned.
1560     // But the stack bang currently assumes that it is a
1561     // multiple of page size. This guarantees that the bang
1562     // loop touches all pages in the shadow zone.
1563     // This can be guaranteed differently, as well.  E.g., if
1564     // the page size is a multiple of 4K, banging in 4K steps
1565     // suffices to touch all pages. (Some pages are banged
1566     // several times, though.)
1567     assert(is_aligned(s, os::vm_page_size()),
1568            "Stack bang assumes multiple of page size.");
1569     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1570     _stack_shadow_zone_size = s;
1571   }
1572 
1573   void create_stack_guard_pages();
1574   void remove_stack_guard_pages();
1575 
1576   void enable_stack_reserved_zone();
1577   void disable_stack_reserved_zone();
1578   void enable_stack_yellow_reserved_zone();
1579   void disable_stack_yellow_reserved_zone();
1580   void enable_stack_red_zone();
1581   void disable_stack_red_zone();
1582 
1583   inline bool stack_guard_zone_unused();
1584   inline bool stack_yellow_reserved_zone_disabled();
1585   inline bool stack_reserved_zone_disabled();
1586   inline bool stack_guards_enabled();
1587 
1588   address reserved_stack_activation() const { return _reserved_stack_activation; }
1589   void set_reserved_stack_activation(address addr) {
1590     assert(_reserved_stack_activation == stack_base()
1591             || _reserved_stack_activation == NULL
1592             || addr == stack_base(), "Must not be set twice");
1593     _reserved_stack_activation = addr;
1594   }
1595 
1596   // Attempt to reguard the stack after a stack overflow may have occurred.
1597   // Returns true if (a) guard pages are not needed on this thread, (b) the
1598   // pages are already guarded, or (c) the pages were successfully reguarded.
1599   // Returns false if there is not enough stack space to reguard the pages, in
1600   // which case the caller should unwind a frame and try again.  The argument
1601   // should be the caller's (approximate) sp.
1602   bool reguard_stack(address cur_sp);
1603   // Similar to above but see if current stackpoint is out of the guard area
1604   // and reguard if possible.
1605   bool reguard_stack(void);
1606 
1607   address stack_overflow_limit() { return _stack_overflow_limit; }
1608   void set_stack_overflow_limit() {
1609     _stack_overflow_limit =
1610       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1611   }
1612 
1613   // Misc. accessors/mutators
1614   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1615   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1616   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1617 
1618 #ifndef PRODUCT
1619   void record_jump(address target, address instr, const char* file, int line);
1620 #endif // PRODUCT
1621 
1622   // For assembly stub generation
1623   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1624 #ifndef PRODUCT
1625   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1626   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1627 #endif // PRODUCT
1628   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1629   static ByteSize pending_jni_exception_check_fn_offset() {
1630     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1631   }
1632   static ByteSize last_Java_sp_offset() {
1633     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1634   }
1635   static ByteSize last_Java_pc_offset() {
1636     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1637   }
1638   static ByteSize frame_anchor_offset() {
1639     return byte_offset_of(JavaThread, _anchor);
1640   }
1641   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1642   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1643   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1644   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1645   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1646   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1647 #if INCLUDE_JVMCI
1648   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1649   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1650   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1651   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1652   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1653   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1654 #endif // INCLUDE_JVMCI
1655   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1656   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1657   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1658   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1659   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1660   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1661   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1662   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1663 
1664   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1665   static ByteSize should_post_on_exceptions_flag_offset() {
1666     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1667   }
1668 
1669 #if INCLUDE_ALL_GCS
1670   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
1671   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
1672 #endif // INCLUDE_ALL_GCS
1673 
1674   // Returns the jni environment for this thread
1675   JNIEnv* jni_environment()                      { return &_jni_environment; }
1676 
1677   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1678     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1679     // Only return NULL if thread is off the thread list; starting to
1680     // exit should not return NULL.
1681     if (thread_from_jni_env->is_terminated()) {
1682       thread_from_jni_env->block_if_vm_exited();
1683       return NULL;
1684     } else {
1685       return thread_from_jni_env;
1686     }
1687   }
1688 
1689   // JNI critical regions. These can nest.
1690   bool in_critical()    { return _jni_active_critical > 0; }
1691   bool in_last_critical()  { return _jni_active_critical == 1; }
1692   void enter_critical() {
1693     assert(Thread::current() == this ||
1694            (Thread::current()->is_VM_thread() &&
1695            SafepointSynchronize::is_synchronizing()),
1696            "this must be current thread or synchronizing");
1697     _jni_active_critical++;
1698   }
1699   void exit_critical() {
1700     assert(Thread::current() == this, "this must be current thread");
1701     _jni_active_critical--;
1702     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1703   }
1704 
1705   // Checked JNI: is the programmer required to check for exceptions, if so specify
1706   // which function name. Returning to a Java frame should implicitly clear the
1707   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1708   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1709   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1710   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1711   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1712   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1713   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1714 
1715   // For deadlock detection
1716   int depth_first_number() { return _depth_first_number; }
1717   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1718 
1719  private:
1720   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1721 
1722  public:
1723   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1724   void add_monitor_chunk(MonitorChunk* chunk);
1725   void remove_monitor_chunk(MonitorChunk* chunk);
1726   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1727   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1728   void dec_in_deopt_handler() {
1729     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1730     if (_in_deopt_handler > 0) { // robustness
1731       _in_deopt_handler--;
1732     }
1733   }
1734 
1735  private:
1736   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1737 
1738  public:
1739 
1740   // Frame iteration; calls the function f for all frames on the stack
1741   void frames_do(void f(frame*, const RegisterMap*));
1742 
1743   // Memory operations
1744   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1745 
1746   // Sweeper operations
1747   virtual void nmethods_do(CodeBlobClosure* cf);
1748 
1749   // RedefineClasses Support
1750   void metadata_do(void f(Metadata*));
1751 
1752   // Misc. operations
1753   char* name() const { return (char*)get_thread_name(); }
1754   void print_on(outputStream* st) const;
1755   void print_value();
1756   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1757   void print_thread_state() const                      PRODUCT_RETURN;
1758   void print_on_error(outputStream* st, char* buf, int buflen) const;
1759   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1760   void verify();
1761   const char* get_thread_name() const;
1762  private:
1763   // factor out low-level mechanics for use in both normal and error cases
1764   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1765  public:
1766   const char* get_threadgroup_name() const;
1767   const char* get_parent_name() const;
1768 
1769   // Accessing frames
1770   frame last_frame() {
1771     _anchor.make_walkable(this);
1772     return pd_last_frame();
1773   }
1774   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1775 
1776   // Returns method at 'depth' java or native frames down the stack
1777   // Used for security checks
1778   Klass* security_get_caller_class(int depth);
1779 
1780   // Print stack trace in external format
1781   void print_stack_on(outputStream* st);
1782   void print_stack() { print_stack_on(tty); }
1783 
1784   // Print stack traces in various internal formats
1785   void trace_stack()                             PRODUCT_RETURN;
1786   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1787   void trace_frames()                            PRODUCT_RETURN;
1788   void trace_oops()                              PRODUCT_RETURN;
1789 
1790   // Print an annotated view of the stack frames
1791   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1792   void validate_frame_layout() {
1793     print_frame_layout(0, true);
1794   }
1795 
1796   // Returns the number of stack frames on the stack
1797   int depth() const;
1798 
1799   // Function for testing deoptimization
1800   void deoptimize();
1801   void make_zombies();
1802 
1803   void deoptimized_wrt_marked_nmethods();
1804 
1805  public:
1806   // Returns the running thread as a JavaThread
1807   static inline JavaThread* current();
1808 
1809   // Returns the active Java thread.  Do not use this if you know you are calling
1810   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1811   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1812   // operation.  You may not want that either.
1813   static JavaThread* active();
1814 
1815   inline CompilerThread* as_CompilerThread();
1816 
1817  public:
1818   virtual void run();
1819   void thread_main_inner();
1820 
1821  private:
1822   // PRIVILEGED STACK
1823   PrivilegedElement*  _privileged_stack_top;
1824   GrowableArray<oop>* _array_for_gc;
1825  public:
1826 
1827   // Returns the privileged_stack information.
1828   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1829   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1830   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1831 
1832  public:
1833   // Thread local information maintained by JVMTI.
1834   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1835   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1836   // getter is used to get this JavaThread's JvmtiThreadState if it has
1837   // one which means NULL can be returned. JvmtiThreadState::state_for()
1838   // is used to get the specified JavaThread's JvmtiThreadState if it has
1839   // one or it allocates a new JvmtiThreadState for the JavaThread and
1840   // returns it. JvmtiThreadState::state_for() will return NULL only if
1841   // the specified JavaThread is exiting.
1842   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1843   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1844   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1845   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1846 
1847   // JVMTI PopFrame support
1848   // Setting and clearing popframe_condition
1849   // All of these enumerated values are bits. popframe_pending
1850   // indicates that a PopFrame() has been requested and not yet been
1851   // completed. popframe_processing indicates that that PopFrame() is in
1852   // the process of being completed. popframe_force_deopt_reexecution_bit
1853   // indicates that special handling is required when returning to a
1854   // deoptimized caller.
1855   enum PopCondition {
1856     popframe_inactive                      = 0x00,
1857     popframe_pending_bit                   = 0x01,
1858     popframe_processing_bit                = 0x02,
1859     popframe_force_deopt_reexecution_bit   = 0x04
1860   };
1861   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1862   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1863   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1864   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1865   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1866   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1867   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1868   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1869 #ifdef CC_INTERP
1870   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1871   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1872   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1873   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1874   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1875 #endif
1876 
1877   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1878   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1879   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1880 
1881  private:
1882   // Saved incoming arguments to popped frame.
1883   // Used only when popped interpreted frame returns to deoptimized frame.
1884   void*    _popframe_preserved_args;
1885   int      _popframe_preserved_args_size;
1886 
1887  public:
1888   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1889   void* popframe_preserved_args();
1890   ByteSize popframe_preserved_args_size();
1891   WordSize popframe_preserved_args_size_in_words();
1892   void  popframe_free_preserved_args();
1893 
1894 
1895  private:
1896   JvmtiThreadState *_jvmti_thread_state;
1897   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1898 
1899   // Used by the interpreter in fullspeed mode for frame pop, method
1900   // entry, method exit and single stepping support. This field is
1901   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1902   // It can be set to zero asynchronously (i.e., without a VM operation
1903   // or a lock) so we have to be very careful.
1904   int               _interp_only_mode;
1905 
1906  public:
1907   // used by the interpreter for fullspeed debugging support (see above)
1908   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1909   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1910   int get_interp_only_mode()                { return _interp_only_mode; }
1911   void increment_interp_only_mode()         { ++_interp_only_mode; }
1912   void decrement_interp_only_mode()         { --_interp_only_mode; }
1913 
1914   // support for cached flag that indicates whether exceptions need to be posted for this thread
1915   // if this is false, we can avoid deoptimizing when events are thrown
1916   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1917  private:
1918   int    _should_post_on_exceptions_flag;
1919 
1920  public:
1921   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1922   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1923 
1924  private:
1925   ThreadStatistics *_thread_stat;
1926 
1927  public:
1928   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1929 
1930   // Return a blocker object for which this thread is blocked parking.
1931   oop current_park_blocker();
1932 
1933  private:
1934   static size_t _stack_size_at_create;
1935 
1936  public:
1937   static inline size_t stack_size_at_create(void) {
1938     return _stack_size_at_create;
1939   }
1940   static inline void set_stack_size_at_create(size_t value) {
1941     _stack_size_at_create = value;
1942   }
1943 
1944 #if INCLUDE_ALL_GCS
1945   // SATB marking queue support
1946   SATBMarkQueue& satb_mark_queue() { return _satb_mark_queue; }



1947 
1948   // Dirty card queue support
1949   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }



1950 #endif // INCLUDE_ALL_GCS
1951 
1952   // Machine dependent stuff
1953 #include OS_CPU_HEADER(thread)
1954 
1955  public:
1956   void set_blocked_on_compilation(bool value) {
1957     _blocked_on_compilation = value;
1958   }
1959 
1960   bool blocked_on_compilation() {
1961     return _blocked_on_compilation;
1962   }
1963  protected:
1964   bool         _blocked_on_compilation;
1965 
1966 
1967   // JSR166 per-thread parker
1968  private:
1969   Parker*    _parker;
1970  public:
1971   Parker*     parker() { return _parker; }
1972 
1973   // Biased locking support
1974  private:
1975   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1976  public:
1977   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1978   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1979 
1980   // clearing/querying jni attach status
1981   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1982   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1983   inline void set_done_attaching_via_jni();
1984 };
1985 
1986 // Inline implementation of JavaThread::current
1987 inline JavaThread* JavaThread::current() {
1988   Thread* thread = Thread::current();
1989   assert(thread->is_Java_thread(), "just checking");
1990   return (JavaThread*)thread;
1991 }
1992 
1993 inline CompilerThread* JavaThread::as_CompilerThread() {
1994   assert(is_Compiler_thread(), "just checking");
1995   return (CompilerThread*)this;
1996 }
1997 
1998 // Dedicated thread to sweep the code cache
1999 class CodeCacheSweeperThread : public JavaThread {
2000   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2001  public:
2002   CodeCacheSweeperThread();
2003   // Track the nmethod currently being scanned by the sweeper
2004   void set_scanned_compiled_method(CompiledMethod* cm) {
2005     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2006     _scanned_compiled_method = cm;
2007   }
2008 
2009   // Hide sweeper thread from external view.
2010   bool is_hidden_from_external_view() const { return true; }
2011 
2012   bool is_Code_cache_sweeper_thread() const { return true; }
2013 
2014   // Prevent GC from unloading _scanned_compiled_method
2015   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2016   void nmethods_do(CodeBlobClosure* cf);
2017 };
2018 
2019 // A thread used for Compilation.
2020 class CompilerThread : public JavaThread {
2021   friend class VMStructs;
2022  private:
2023   CompilerCounters* _counters;
2024 
2025   ciEnv*                _env;
2026   CompileLog*           _log;
2027   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2028   CompileQueue*         _queue;
2029   BufferBlob*           _buffer_blob;
2030 
2031   AbstractCompiler*     _compiler;
2032 
2033  public:
2034 
2035   static CompilerThread* current();
2036 
2037   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2038 
2039   bool is_Compiler_thread() const                { return true; }
2040 
2041   virtual bool can_call_java() const;
2042 
2043   // Hide native compiler threads from external view.
2044   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2045 
2046   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2047   AbstractCompiler* compiler() const             { return _compiler; }
2048 
2049   CompileQueue* queue()        const             { return _queue; }
2050   CompilerCounters* counters() const             { return _counters; }
2051 
2052   // Get/set the thread's compilation environment.
2053   ciEnv*        env()                            { return _env; }
2054   void          set_env(ciEnv* env)              { _env = env; }
2055 
2056   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2057   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2058 
2059   // Get/set the thread's logging information
2060   CompileLog*   log()                            { return _log; }
2061   void          init_log(CompileLog* log) {
2062     // Set once, for good.
2063     assert(_log == NULL, "set only once");
2064     _log = log;
2065   }
2066 
2067 #ifndef PRODUCT
2068  private:
2069   IdealGraphPrinter *_ideal_graph_printer;
2070  public:
2071   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2072   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2073 #endif
2074 
2075   // Get/set the thread's current task
2076   CompileTask* task()                      { return _task; }
2077   void         set_task(CompileTask* task) { _task = task; }
2078 };
2079 
2080 inline CompilerThread* CompilerThread::current() {
2081   return JavaThread::current()->as_CompilerThread();
2082 }
2083 
2084 // The active thread queue. It also keeps track of the current used
2085 // thread priorities.
2086 class Threads: AllStatic {
2087   friend class VMStructs;
2088  private:
2089   static JavaThread* _thread_list;
2090   static int         _number_of_threads;
2091   static int         _number_of_non_daemon_threads;
2092   static int         _return_code;
2093   static int         _thread_claim_parity;
2094 #ifdef ASSERT
2095   static bool        _vm_complete;
2096 #endif
2097 
2098   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2099   static void initialize_jsr292_core_classes(TRAPS);
2100 
2101  public:
2102   // Thread management
2103   // force_daemon is a concession to JNI, where we may need to add a
2104   // thread to the thread list before allocating its thread object
2105   static void add(JavaThread* p, bool force_daemon = false);
2106   static void remove(JavaThread* p);
2107   static void threads_do(ThreadClosure* tc);
2108   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2109 
2110   // Initializes the vm and creates the vm thread
2111   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2112   static void convert_vm_init_libraries_to_agents();
2113   static void create_vm_init_libraries();
2114   static void create_vm_init_agents();
2115   static void shutdown_vm_agents();
2116   static bool destroy_vm();
2117   // Supported VM versions via JNI
2118   // Includes JNI_VERSION_1_1
2119   static jboolean is_supported_jni_version_including_1_1(jint version);
2120   // Does not include JNI_VERSION_1_1
2121   static jboolean is_supported_jni_version(jint version);
2122 
2123   // The "thread claim parity" provides a way for threads to be claimed
2124   // by parallel worker tasks.
2125   //
2126   // Each thread contains a a "parity" field. A task will claim the
2127   // thread only if its parity field is the same as the global parity,
2128   // which is updated by calling change_thread_claim_parity().
2129   //
2130   // For this to work change_thread_claim_parity() needs to be called
2131   // exactly once in sequential code before starting parallel tasks
2132   // that should claim threads.
2133   //
2134   // New threads get their parity set to 0 and change_thread_claim_parity()
2135   // never set the global parity to 0.
2136   static int thread_claim_parity() { return _thread_claim_parity; }
2137   static void change_thread_claim_parity();
2138   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2139 
2140   // Apply "f->do_oop" to all root oops in all threads.
2141   // This version may only be called by sequential code.
2142   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2143   // This version may be called by sequential or parallel code.
2144   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2145   // This creates a list of GCTasks, one per thread.
2146   static void create_thread_roots_tasks(GCTaskQueue* q);
2147   // This creates a list of GCTasks, one per thread, for marking objects.
2148   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
2149 
2150   // Apply "f->do_oop" to roots in all threads that
2151   // are part of compiled frames
2152   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2153 
2154   static void convert_hcode_pointers();
2155   static void restore_hcode_pointers();
2156 
2157   // Sweeper
2158   static void nmethods_do(CodeBlobClosure* cf);
2159 
2160   // RedefineClasses support
2161   static void metadata_do(void f(Metadata*));
2162   static void metadata_handles_do(void f(Metadata*));
2163 
2164 #ifdef ASSERT
2165   static bool is_vm_complete() { return _vm_complete; }
2166 #endif
2167 
2168   // Verification
2169   static void verify();
2170   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
2171   static void print(bool print_stacks, bool internal_format) {
2172     // this function is only used by debug.cpp
2173     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
2174   }
2175   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2176   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2177                              int buflen, bool* found_current);
2178   static void print_threads_compiling(outputStream* st, char* buf, int buflen);
2179 
2180   // Get Java threads that are waiting to enter a monitor.
2181   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2182                                                          int count, address monitor);
2183 
2184   // Get owning Java thread from the monitor's owner field.
2185   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2186                                                       address owner);
2187 
2188   // Number of threads on the active threads list
2189   static int number_of_threads()                 { return _number_of_threads; }
2190   // Number of non-daemon threads on the active threads list
2191   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2192 
2193   // Deoptimizes all frames tied to marked nmethods
2194   static void deoptimized_wrt_marked_nmethods();
2195 };
2196 
2197 
2198 // Thread iterator
2199 class ThreadClosure: public StackObj {
2200  public:
2201   virtual void do_thread(Thread* thread) = 0;
2202 };
2203 
2204 class SignalHandlerMark: public StackObj {
2205  private:
2206   Thread* _thread;
2207  public:
2208   SignalHandlerMark(Thread* t) {
2209     _thread = t;
2210     if (_thread) _thread->enter_signal_handler();
2211   }
2212   ~SignalHandlerMark() {
2213     if (_thread) _thread->leave_signal_handler();
2214     _thread = NULL;
2215   }
2216 };
2217 
2218 
2219 #endif // SHARE_VM_RUNTIME_THREAD_HPP
--- EOF ---