1 /*
   2  * Copyright (c) 1997, 2019, 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_RUNTIME_THREAD_HPP
  26 #define SHARE_RUNTIME_THREAD_HPP
  27 
  28 #include "jni.h"
  29 #include "code/compiledMethod.hpp"
  30 #include "gc/shared/gcThreadLocalData.hpp"
  31 #include "gc/shared/threadLocalAllocBuffer.hpp"
  32 #include "memory/allocation.hpp"
  33 #include "oops/oop.hpp"
  34 #include "prims/jvmtiExport.hpp"
  35 #include "runtime/frame.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/handshake.hpp"
  38 #include "runtime/javaFrameAnchor.hpp"
  39 #include "runtime/jniHandles.hpp"
  40 #include "runtime/mutexLocker.hpp"
  41 #include "runtime/os.hpp"
  42 #include "runtime/osThread.hpp"
  43 #include "runtime/park.hpp"
  44 #include "runtime/stubRoutines.hpp"
  45 #include "runtime/threadHeapSampler.hpp"
  46 #include "runtime/threadLocalStorage.hpp"
  47 #include "runtime/threadStatisticalInfo.hpp"
  48 #include "runtime/unhandledOops.hpp"
  49 #include "utilities/align.hpp"
  50 #include "utilities/exceptions.hpp"
  51 #include "utilities/macros.hpp"
  52 #ifdef ZERO
  53 # include "stack_zero.hpp"
  54 #endif
  55 #if INCLUDE_JFR
  56 #include "jfr/support/jfrThreadExtension.hpp"
  57 #endif
  58 
  59 
  60 class SafeThreadsListPtr;
  61 class ThreadSafepointState;
  62 class ThreadsList;
  63 class ThreadsSMRSupport;
  64 
  65 class JvmtiThreadState;
  66 class ThreadStatistics;
  67 class ConcurrentLocksDump;
  68 class ParkEvent;
  69 class Parker;
  70 class MonitorInfo;
  71 
  72 class ciEnv;
  73 class CompileThread;
  74 class CompileLog;
  75 class CompileTask;
  76 class CompileQueue;
  77 class CompilerCounters;
  78 
  79 class vframeArray;
  80 class vframe;
  81 class javaVFrame;
  82 
  83 class DeoptResourceMark;
  84 class jvmtiDeferredLocalVariableSet;
  85 
  86 class GCTaskQueue;
  87 class ThreadClosure;
  88 class ICRefillVerifier;
  89 class IdealGraphPrinter;
  90 
  91 class JVMCIEnv;
  92 class JVMCIPrimitiveArray;
  93 
  94 class Metadata;
  95 class ResourceArea;
  96 
  97 DEBUG_ONLY(class ResourceMark;)
  98 
  99 class WorkerThread;
 100 
 101 // Class hierarchy
 102 // - Thread
 103 //   - JavaThread
 104 //     - various subclasses eg CompilerThread, ServiceThread
 105 //   - NonJavaThread
 106 //     - NamedThread
 107 //       - VMThread
 108 //       - ConcurrentGCThread
 109 //       - WorkerThread
 110 //         - GangWorker
 111 //         - GCTaskThread
 112 //     - WatcherThread
 113 //     - JfrThreadSampler
 114 //
 115 // All Thread subclasses must be either JavaThread or NonJavaThread.
 116 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 117 // a partially constructed/destroyed Thread.
 118 
 119 // Thread execution sequence and actions:
 120 // All threads:
 121 //  - thread_native_entry  // per-OS native entry point
 122 //    - stack initialization
 123 //    - other OS-level initialization (signal masks etc)
 124 //    - handshake with creating thread (if not started suspended)
 125 //    - this->call_run()  // common shared entry point
 126 //      - shared common initialization
 127 //      - this->pre_run()  // virtual per-thread-type initialization
 128 //      - this->run()      // virtual per-thread-type "main" logic
 129 //      - shared common tear-down
 130 //      - this->post_run()  // virtual per-thread-type tear-down
 131 //      - // 'this' no longer referenceable
 132 //    - OS-level tear-down (minimal)
 133 //    - final logging
 134 //
 135 // For JavaThread:
 136 //   - this->run()  // virtual but not normally overridden
 137 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 138 //       - this->entry_point()  // set differently for each kind of JavaThread
 139 
 140 class Thread: public ThreadShadow {
 141   friend class VMStructs;
 142   friend class JVMCIVMStructs;
 143  private:
 144 
 145 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 146   // Current thread is maintained as a thread-local variable
 147   static THREAD_LOCAL_DECL Thread* _thr_current;
 148 #endif
 149 
 150   // Thread local data area available to the GC. The internal
 151   // structure and contents of this data area is GC-specific.
 152   // Only GC and GC barrier code should access this data area.
 153   GCThreadLocalData _gc_data;
 154 
 155  public:
 156   static ByteSize gc_data_offset() {
 157     return byte_offset_of(Thread, _gc_data);
 158   }
 159 
 160   template <typename T> T* gc_data() {
 161     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 162     return reinterpret_cast<T*>(&_gc_data);
 163   }
 164 
 165   // Exception handling
 166   // (Note: _pending_exception and friends are in ThreadShadow)
 167   //oop       _pending_exception;                // pending exception for current thread
 168   // const char* _exception_file;                   // file information for exception (debugging only)
 169   // int         _exception_line;                   // line information for exception (debugging only)
 170  protected:
 171 
 172   DEBUG_ONLY(static Thread* _starting_thread;)
 173 
 174   // Support for forcing alignment of thread objects for biased locking
 175   void*       _real_malloc_address;
 176 
 177   // JavaThread lifecycle support:
 178   friend class SafeThreadsListPtr;  // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
 179   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 180   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 181   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 182   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 183 
 184   ThreadsList* volatile _threads_hazard_ptr;
 185   SafeThreadsListPtr*   _threads_list_ptr;
 186   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 187   ThreadsList*          get_threads_hazard_ptr();
 188   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 189   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 190     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 191   }
 192   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 193     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 194   }
 195   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 196     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 197   }
 198   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 199   uint _nested_threads_hazard_ptr_cnt;
 200   void dec_nested_threads_hazard_ptr_cnt() {
 201     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 202     _nested_threads_hazard_ptr_cnt--;
 203   }
 204   void inc_nested_threads_hazard_ptr_cnt() {
 205     _nested_threads_hazard_ptr_cnt++;
 206   }
 207   uint nested_threads_hazard_ptr_cnt() {
 208     return _nested_threads_hazard_ptr_cnt;
 209   }
 210 
 211  public:
 212   void* operator new(size_t size) throw() { return allocate(size, true); }
 213   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 214     return allocate(size, false); }
 215   void  operator delete(void* p);
 216 
 217  protected:
 218   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 219  private:
 220 
 221   // ***************************************************************
 222   // Suspend and resume support
 223   // ***************************************************************
 224   //
 225   // VM suspend/resume no longer exists - it was once used for various
 226   // things including safepoints but was deprecated and finally removed
 227   // in Java 7. Because VM suspension was considered "internal" Java-level
 228   // suspension was considered "external", and this legacy naming scheme
 229   // remains.
 230   //
 231   // External suspend/resume requests come from JVM_SuspendThread,
 232   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 233   // ResumeThread. External
 234   // suspend requests cause _external_suspend to be set and external
 235   // resume requests cause _external_suspend to be cleared.
 236   // External suspend requests do not nest on top of other external
 237   // suspend requests. The higher level APIs reject suspend requests
 238   // for already suspended threads.
 239   //
 240   // The external_suspend
 241   // flag is checked by has_special_runtime_exit_condition() and java thread
 242   // will self-suspend when handle_special_runtime_exit_condition() is
 243   // called. Most uses of the _thread_blocked state in JavaThreads are
 244   // considered the same as being externally suspended; if the blocking
 245   // condition lifts, the JavaThread will self-suspend. Other places
 246   // where VM checks for external_suspend include:
 247   //   + mutex granting (do not enter monitors when thread is suspended)
 248   //   + state transitions from _thread_in_native
 249   //
 250   // In general, java_suspend() does not wait for an external suspend
 251   // request to complete. When it returns, the only guarantee is that
 252   // the _external_suspend field is true.
 253   //
 254   // wait_for_ext_suspend_completion() is used to wait for an external
 255   // suspend request to complete. External suspend requests are usually
 256   // followed by some other interface call that requires the thread to
 257   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 258   // the interface that requires quiescence, we give the JavaThread a
 259   // chance to self-suspend before we need it to be quiescent. This
 260   // improves overall suspend/query performance.
 261   //
 262   // _suspend_flags controls the behavior of java_ suspend/resume.
 263   // It must be set under the protection of SR_lock. Read from the flag is
 264   // OK without SR_lock as long as the value is only used as a hint.
 265   // (e.g., check _external_suspend first without lock and then recheck
 266   // inside SR_lock and finish the suspension)
 267   //
 268   // _suspend_flags is also overloaded for other "special conditions" so
 269   // that a single check indicates whether any special action is needed
 270   // eg. for async exceptions.
 271   // -------------------------------------------------------------------
 272   // Notes:
 273   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 274   // but we still update its value to keep other part of the system (mainly
 275   // JVMTI) happy. ThreadState is legacy code (see notes in
 276   // osThread.hpp).
 277   //
 278   // 2. It would be more natural if set_external_suspend() is private and
 279   // part of java_suspend(), but that probably would affect the suspend/query
 280   // performance. Need more investigation on this.
 281 
 282   // suspend/resume lock: used for self-suspend
 283   Monitor* _SR_lock;
 284 
 285  protected:
 286   enum SuspendFlags {
 287     // NOTE: avoid using the sign-bit as cc generates different test code
 288     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 289 
 290     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 291     _ext_suspended          = 0x40000000U, // thread has self-suspended
 292 
 293     _has_async_exception    = 0x00000001U, // there is a pending async exception
 294     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 295 
 296     _trace_flag             = 0x00000004U  // call tracing backend
 297   };
 298 
 299   // various suspension related flags - atomically updated
 300   // overloaded for async exception checking in check_special_condition_for_native_trans.
 301   volatile uint32_t _suspend_flags;
 302 
 303  private:
 304   int _num_nested_signal;
 305 
 306   DEBUG_ONLY(bool _suspendible_thread;)
 307 
 308  public:
 309   void enter_signal_handler() { _num_nested_signal++; }
 310   void leave_signal_handler() { _num_nested_signal--; }
 311   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 312 
 313   // Determines if a heap allocation failure will be retried
 314   // (e.g., by deoptimizing and re-executing in the interpreter).
 315   // In this case, the failed allocation must raise
 316   // Universe::out_of_memory_error_retry() and omit side effects
 317   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 318   // and -XX:OnOutOfMemoryError.
 319   virtual bool in_retryable_allocation() const { return false; }
 320 
 321 #ifdef ASSERT
 322   void set_suspendible_thread() {
 323     _suspendible_thread = true;
 324   }
 325 
 326   void clear_suspendible_thread() {
 327     _suspendible_thread = false;
 328   }
 329 
 330   bool is_suspendible_thread() { return _suspendible_thread; }
 331 #endif
 332 
 333  private:
 334   // Active_handles points to a block of handles
 335   JNIHandleBlock* _active_handles;
 336 
 337   // One-element thread local free list
 338   JNIHandleBlock* _free_handle_block;
 339 
 340   // Point to the last handle mark
 341   HandleMark* _last_handle_mark;
 342 
 343   // Claim value for parallel iteration over threads.
 344   uintx _threads_do_token;
 345 
 346   // Support for GlobalCounter
 347  private:
 348   volatile uintx _rcu_counter;
 349  public:
 350   volatile uintx* get_rcu_counter() {
 351     return &_rcu_counter;
 352   }
 353 
 354  public:
 355   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 356   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 357  private:
 358 
 359 #ifdef ASSERT
 360   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 361 
 362  public:
 363   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 364     return _missed_ic_stub_refill_verifier;
 365   }
 366 
 367   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 368     _missed_ic_stub_refill_verifier = verifier;
 369   }
 370 #endif
 371 
 372  private:
 373 
 374   // debug support for checking if code does allow safepoints or not
 375   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 376   // mutex, or blocking on an object synchronizer (Java locking).
 377   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 378   // If !allow_allocation(), then an assertion failure will happen during allocation
 379   // (Hence, !allow_safepoint() => !allow_allocation()).
 380   //
 381   // The two classes NoSafepointVerifier and No_Allocation_Verifier are used to set these counters.
 382   //
 383   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 384   debug_only(int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 385 
 386   // Used by SkipGCALot class.
 387   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 388 
 389   friend class NoAllocVerifier;
 390   friend class NoSafepointVerifier;
 391   friend class PauseNoSafepointVerifier;
 392   friend class GCLocker;
 393 
 394   volatile void* _polling_page;                 // Thread local polling page
 395 
 396   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 397   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 398                                                 // the Java heap
 399   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 400 
 401   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 402 
 403   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 404 
 405   int   _vm_operation_started_count;            // VM_Operation support
 406   int   _vm_operation_completed_count;          // VM_Operation support
 407 
 408   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 409                                                 // is waiting to lock
 410   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 411 
 412   // ObjectMonitor on which this thread called Object.wait()
 413   ObjectMonitor* _current_waiting_monitor;
 414 
 415   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 416  public:
 417   ObjectMonitor* omFreeList;
 418   int omFreeCount;                              // length of omFreeList
 419   int omFreeProvision;                          // reload chunk size
 420   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 421   int omInUseCount;                             // length of omInUseList
 422 
 423 #ifdef ASSERT
 424  private:
 425   volatile uint64_t _visited_for_critical_count;
 426 
 427  public:
 428   void set_visited_for_critical_count(uint64_t safepoint_id) {
 429     assert(_visited_for_critical_count == 0, "Must be reset before set");
 430     assert((safepoint_id & 0x1) == 1, "Must be odd");
 431     _visited_for_critical_count = safepoint_id;
 432   }
 433   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 434     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 435     _visited_for_critical_count = 0;
 436   }
 437   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 438     return _visited_for_critical_count == safepoint_id;
 439   }
 440 #endif
 441 
 442  public:
 443   enum {
 444     is_definitely_current_thread = true
 445   };
 446 
 447  public:
 448   // Constructor
 449   Thread();
 450   virtual ~Thread() = 0;        // Thread is abstract.
 451 
 452   // Manage Thread::current()
 453   void initialize_thread_current();
 454   static void clear_thread_current(); // TLS cleanup needed before threads terminate
 455 
 456  protected:
 457   // To be implemented by children.
 458   virtual void run() = 0;
 459   virtual void pre_run() = 0;
 460   virtual void post_run() = 0;  // Note: Thread must not be deleted prior to calling this!
 461 
 462 #ifdef ASSERT
 463   enum RunState {
 464     PRE_CALL_RUN,
 465     CALL_RUN,
 466     PRE_RUN,
 467     RUN,
 468     POST_RUN
 469     // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
 470   };
 471   RunState _run_state;  // for lifecycle checks
 472 #endif
 473 
 474 
 475  public:
 476   // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
 477   void call_run();
 478 
 479   // Testers
 480   virtual bool is_VM_thread()       const            { return false; }
 481   virtual bool is_Java_thread()     const            { return false; }
 482   virtual bool is_Compiler_thread() const            { return false; }
 483   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 484   virtual bool is_hidden_from_external_view() const  { return false; }
 485   virtual bool is_jvmti_agent_thread() const         { return false; }
 486   // True iff the thread can perform GC operations at a safepoint.
 487   // Generally will be true only of VM thread and parallel GC WorkGang
 488   // threads.
 489   virtual bool is_GC_task_thread() const             { return false; }
 490   virtual bool is_Watcher_thread() const             { return false; }
 491   virtual bool is_ConcurrentGC_thread() const        { return false; }
 492   virtual bool is_Named_thread() const               { return false; }
 493   virtual bool is_Worker_thread() const              { return false; }
 494 
 495   // Can this thread make Java upcalls
 496   virtual bool can_call_java() const                 { return false; }
 497 
 498   // Casts
 499   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 500 
 501   virtual char* name() const { return (char*)"Unknown thread"; }
 502 
 503   // Returns the current thread (ASSERTS if NULL)
 504   static inline Thread* current();
 505   // Returns the current thread, or NULL if not attached
 506   static inline Thread* current_or_null();
 507   // Returns the current thread, or NULL if not attached, and is
 508   // safe for use from signal-handlers
 509   static inline Thread* current_or_null_safe();
 510 
 511   // Common thread operations
 512 #ifdef ASSERT
 513   static void check_for_dangling_thread_pointer(Thread *thread);
 514 #endif
 515   static void set_priority(Thread* thread, ThreadPriority priority);
 516   static ThreadPriority get_priority(const Thread* const thread);
 517   static void start(Thread* thread);
 518   static void interrupt(Thread* thr);
 519   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 520 
 521   void set_native_thread_name(const char *name) {
 522     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 523     os::set_native_thread_name(name);
 524   }
 525 
 526   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 527   Monitor* SR_lock() const                       { return _SR_lock; }
 528 
 529   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 530 
 531   inline void set_suspend_flag(SuspendFlags f);
 532   inline void clear_suspend_flag(SuspendFlags f);
 533 
 534   inline void set_has_async_exception();
 535   inline void clear_has_async_exception();
 536 
 537   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 538 
 539   inline void set_critical_native_unlock();
 540   inline void clear_critical_native_unlock();
 541 
 542   inline void set_trace_flag();
 543   inline void clear_trace_flag();
 544 
 545   // Support for Unhandled Oop detection
 546   // Add the field for both, fastdebug and debug, builds to keep
 547   // Thread's fields layout the same.
 548   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 549 #ifdef CHECK_UNHANDLED_OOPS
 550  private:
 551   UnhandledOops* _unhandled_oops;
 552 #elif defined(ASSERT)
 553  private:
 554   void* _unhandled_oops;
 555 #endif
 556 #ifdef CHECK_UNHANDLED_OOPS
 557  public:
 558   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 559   // Mark oop safe for gc.  It may be stack allocated but won't move.
 560   void allow_unhandled_oop(oop *op) {
 561     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 562   }
 563   // Clear oops at safepoint so crashes point to unhandled oop violator
 564   void clear_unhandled_oops() {
 565     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 566   }
 567 #endif // CHECK_UNHANDLED_OOPS
 568 
 569  public:
 570 #ifndef PRODUCT
 571   bool skip_gcalot()           { return _skip_gcalot; }
 572   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 573 #endif
 574 
 575   // Installs a pending exception to be inserted later
 576   static void send_async_exception(oop thread_oop, oop java_throwable);
 577 
 578   // Resource area
 579   ResourceArea* resource_area() const            { return _resource_area; }
 580   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 581 
 582   OSThread* osthread() const                     { return _osthread;   }
 583   void set_osthread(OSThread* thread)            { _osthread = thread; }
 584 
 585   // JNI handle support
 586   JNIHandleBlock* active_handles() const         { return _active_handles; }
 587   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 588   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 589   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 590 
 591   // Internal handle support
 592   HandleArea* handle_area() const                { return _handle_area; }
 593   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 594 
 595   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 596   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 597 
 598   // Thread-Local Allocation Buffer (TLAB) support
 599   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 600   void initialize_tlab() {
 601     if (UseTLAB) {
 602       tlab().initialize();
 603     }
 604   }
 605 
 606   jlong allocated_bytes()               { return _allocated_bytes; }
 607   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 608   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 609   inline jlong cooked_allocated_bytes();
 610 
 611   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 612 
 613   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 614 
 615   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 616 
 617   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 618 
 619   // VM operation support
 620   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 621   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 622   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 623 
 624   // For tracking the heavyweight monitor the thread is pending on.
 625   ObjectMonitor* current_pending_monitor() {
 626     return _current_pending_monitor;
 627   }
 628   void set_current_pending_monitor(ObjectMonitor* monitor) {
 629     _current_pending_monitor = monitor;
 630   }
 631   void set_current_pending_monitor_is_from_java(bool from_java) {
 632     _current_pending_monitor_is_from_java = from_java;
 633   }
 634   bool current_pending_monitor_is_from_java() {
 635     return _current_pending_monitor_is_from_java;
 636   }
 637 
 638   // For tracking the ObjectMonitor on which this thread called Object.wait()
 639   ObjectMonitor* current_waiting_monitor() {
 640     return _current_waiting_monitor;
 641   }
 642   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 643     _current_waiting_monitor = monitor;
 644   }
 645 
 646   // GC support
 647   // Apply "f->do_oop" to all root oops in "this".
 648   //   Used by JavaThread::oops_do.
 649   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 650   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 651 
 652   // Handles the parallel case for claim_threads_do.
 653  private:
 654   bool claim_par_threads_do(uintx claim_token);
 655  public:
 656   // Requires that "claim_token" is that of the current iteration.
 657   // If "is_par" is false, sets the token of "this" to
 658   // "claim_token", and returns "true".  If "is_par" is true,
 659   // uses an atomic instruction to set the current thread's token to
 660   // "claim_token", if it is not already.  Returns "true" iff the
 661   // calling thread does the update, this indicates that the calling thread
 662   // has claimed the thread in the current iteration.
 663   bool claim_threads_do(bool is_par, uintx claim_token) {
 664     if (!is_par) {
 665       _threads_do_token = claim_token;
 666       return true;
 667     } else {
 668       return claim_par_threads_do(claim_token);
 669     }
 670   }
 671 
 672   uintx threads_do_token() const { return _threads_do_token; }
 673 
 674   // jvmtiRedefineClasses support
 675   void metadata_handles_do(void f(Metadata*));
 676 
 677   // Used by fast lock support
 678   virtual bool is_lock_owned(address adr) const;
 679 
 680   // Check if address is in the stack of the thread (not just for locks).
 681   // Warning: the method can only be used on the running thread
 682   bool is_in_stack(address adr) const;
 683   // Check if address is in the usable part of the stack (excludes protected
 684   // guard pages)
 685   bool is_in_usable_stack(address adr) const;
 686 
 687   // Sets this thread as starting thread. Returns failure if thread
 688   // creation fails due to lack of memory, too many threads etc.
 689   bool set_as_starting_thread();
 690 
 691 protected:
 692   // OS data associated with the thread
 693   OSThread* _osthread;  // Platform-specific thread information
 694 
 695   // Thread local resource area for temporary allocation within the VM
 696   ResourceArea* _resource_area;
 697 
 698   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 699 
 700   // Thread local handle area for allocation of handles within the VM
 701   HandleArea* _handle_area;
 702   GrowableArray<Metadata*>* _metadata_handles;
 703 
 704   // Support for stack overflow handling, get_thread, etc.
 705   address          _stack_base;
 706   size_t           _stack_size;
 707   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 708   int              _lgrp_id;
 709 
 710   volatile void** polling_page_addr() { return &_polling_page; }
 711 
 712  public:
 713   // Stack overflow support
 714   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 715   void    set_stack_base(address base) { _stack_base = base; }
 716   size_t  stack_size() const           { return _stack_size; }
 717   void    set_stack_size(size_t size)  { _stack_size = size; }
 718   address stack_end()  const           { return stack_base() - stack_size(); }
 719   void    record_stack_base_and_size();
 720   void    register_thread_stack_with_NMT() NOT_NMT_RETURN;
 721 
 722   bool    on_local_stack(address adr) const {
 723     // QQQ this has knowledge of direction, ought to be a stack method
 724     return (_stack_base >= adr && adr >= stack_end());
 725   }
 726 
 727   uintptr_t self_raw_id()                    { return _self_raw_id; }
 728   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 729 
 730   int     lgrp_id() const        { return _lgrp_id; }
 731   void    set_lgrp_id(int value) { _lgrp_id = value; }
 732 
 733   // Printing
 734   void print_on(outputStream* st, bool print_extended_info) const;
 735   virtual void print_on(outputStream* st) const { print_on(st, false); }
 736   void print() const;
 737   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 738   void print_value_on(outputStream* st) const;
 739 
 740   // Debug-only code
 741 #ifdef ASSERT
 742  private:
 743   // Deadlock detection support for Mutex locks. List of locks own by thread.
 744   Monitor* _owned_locks;
 745   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 746   // thus the friendship
 747   friend class Mutex;
 748   friend class Monitor;
 749 
 750  public:
 751   void print_owned_locks_on(outputStream* st) const;
 752   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 753   Monitor* owned_locks() const                   { return _owned_locks;          }
 754   bool owns_locks() const                        { return owned_locks() != NULL; }
 755   bool owns_locks_but_compiled_lock() const;
 756 
 757   // Deadlock detection
 758   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 759   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 760   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 761 #endif
 762 
 763   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 764 
 765  private:
 766   volatile int _jvmti_env_iteration_count;
 767 
 768  public:
 769   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 770   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 771   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 772 
 773   // Code generation
 774   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 775   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 776   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 777 
 778   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 779   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 780 
 781   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 782 
 783   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 784   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 785   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 786   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 787 
 788   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 789 
 790   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 791 
 792  public:
 793   volatile intptr_t _Stalled;
 794   volatile int _TypeTag;
 795   ParkEvent * _ParkEvent;                     // for synchronized()
 796   ParkEvent * _SleepEvent;                    // for Thread.sleep
 797   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 798   int NativeSyncRecursion;                    // diagnostic
 799 
 800   volatile int _OnTrap;                       // Resume-at IP delta
 801   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 802   jint _hashStateX;                           // thread-specific hashCode generator state
 803   jint _hashStateY;
 804   jint _hashStateZ;
 805 
 806   // Low-level leaf-lock primitives used to implement synchronization
 807   // and native monitor-mutex infrastructure.
 808   // Not for general synchronization use.
 809   static void SpinAcquire(volatile int * Lock, const char * Name);
 810   static void SpinRelease(volatile int * Lock);
 811   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 812   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 813   static void muxRelease(volatile intptr_t * Lock);
 814 };
 815 
 816 // Inline implementation of Thread::current()
 817 inline Thread* Thread::current() {
 818   Thread* current = current_or_null();
 819   assert(current != NULL, "Thread::current() called on detached thread");
 820   return current;
 821 }
 822 
 823 inline Thread* Thread::current_or_null() {
 824 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 825   return _thr_current;
 826 #else
 827   if (ThreadLocalStorage::is_initialized()) {
 828     return ThreadLocalStorage::thread();
 829   }
 830   return NULL;
 831 #endif
 832 }
 833 
 834 inline Thread* Thread::current_or_null_safe() {
 835   if (ThreadLocalStorage::is_initialized()) {
 836     return ThreadLocalStorage::thread();
 837   }
 838   return NULL;
 839 }
 840 
 841 class NonJavaThread: public Thread {
 842   friend class VMStructs;
 843 
 844   NonJavaThread* volatile _next;
 845 
 846   class List;
 847   static List _the_list;
 848 
 849   void add_to_the_list();
 850   void remove_from_the_list();
 851 
 852  protected:
 853   virtual void pre_run();
 854   virtual void post_run();
 855 
 856  public:
 857   NonJavaThread();
 858   ~NonJavaThread();
 859 
 860   class Iterator;
 861 };
 862 
 863 // Provides iteration over the list of NonJavaThreads.
 864 // List addition occurs in pre_run(), and removal occurs in post_run(),
 865 // so that only live fully-initialized threads can be found in the list.
 866 // Threads created after an iterator is constructed will not be visited
 867 // by the iterator. The scope of an iterator is a critical section; there
 868 // must be no safepoint checks in that scope.
 869 class NonJavaThread::Iterator : public StackObj {
 870   uint _protect_enter;
 871   NonJavaThread* _current;
 872 
 873   // Noncopyable.
 874   Iterator(const Iterator&);
 875   Iterator& operator=(const Iterator&);
 876 
 877 public:
 878   Iterator();
 879   ~Iterator();
 880 
 881   bool end() const { return _current == NULL; }
 882   NonJavaThread* current() const { return _current; }
 883   void step();
 884 };
 885 
 886 // Name support for threads.  non-JavaThread subclasses with multiple
 887 // uniquely named instances should derive from this.
 888 class NamedThread: public NonJavaThread {
 889   friend class VMStructs;
 890   enum {
 891     max_name_len = 64
 892   };
 893  private:
 894   char* _name;
 895   // log JavaThread being processed by oops_do
 896   JavaThread* _processed_thread;
 897   uint _gc_id; // The current GC id when a thread takes part in GC
 898 
 899  public:
 900   NamedThread();
 901   ~NamedThread();
 902   // May only be called once per thread.
 903   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 904   virtual bool is_Named_thread() const { return true; }
 905   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 906   JavaThread *processed_thread() { return _processed_thread; }
 907   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 908   virtual void print_on(outputStream* st) const;
 909 
 910   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 911   uint gc_id() { return _gc_id; }
 912 };
 913 
 914 // Worker threads are named and have an id of an assigned work.
 915 class WorkerThread: public NamedThread {
 916  private:
 917   uint _id;
 918  public:
 919   WorkerThread() : _id(0)               { }
 920   virtual bool is_Worker_thread() const { return true; }
 921 
 922   virtual WorkerThread* as_Worker_thread() const {
 923     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 924     return (WorkerThread*) this;
 925   }
 926 
 927   void set_id(uint work_id)             { _id = work_id; }
 928   uint id() const                       { return _id; }
 929 };
 930 
 931 // A single WatcherThread is used for simulating timer interrupts.
 932 class WatcherThread: public NonJavaThread {
 933   friend class VMStructs;
 934  protected:
 935   virtual void run();
 936 
 937  private:
 938   static WatcherThread* _watcher_thread;
 939 
 940   static bool _startable;
 941   // volatile due to at least one lock-free read
 942   volatile static bool _should_terminate;
 943  public:
 944   enum SomeConstants {
 945     delay_interval = 10                          // interrupt delay in milliseconds
 946   };
 947 
 948   // Constructor
 949   WatcherThread();
 950 
 951   // No destruction allowed
 952   ~WatcherThread() {
 953     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 954   }
 955 
 956   // Tester
 957   bool is_Watcher_thread() const                 { return true; }
 958 
 959   // Printing
 960   char* name() const { return (char*)"VM Periodic Task Thread"; }
 961   void print_on(outputStream* st) const;
 962   void unpark();
 963 
 964   // Returns the single instance of WatcherThread
 965   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 966 
 967   // Create and start the single instance of WatcherThread, or stop it on shutdown
 968   static void start();
 969   static void stop();
 970   // Only allow start once the VM is sufficiently initialized
 971   // Otherwise the first task to enroll will trigger the start
 972   static void make_startable();
 973  private:
 974   int sleep() const;
 975 };
 976 
 977 
 978 class CompilerThread;
 979 
 980 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 981 
 982 class JavaThread: public Thread {
 983   friend class VMStructs;
 984   friend class JVMCIVMStructs;
 985   friend class WhiteBox;
 986   friend class VTBuffer;
 987  private:
 988   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 989   oop            _threadObj;                     // The Java level thread object
 990 
 991 #ifdef ASSERT
 992  private:
 993   int _java_call_counter;
 994 
 995  public:
 996   int  java_call_counter()                       { return _java_call_counter; }
 997   void inc_java_call_counter()                   { _java_call_counter++; }
 998   void dec_java_call_counter() {
 999     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
1000     _java_call_counter--;
1001   }
1002  private:  // restore original namespace restriction
1003 #endif  // ifdef ASSERT
1004 
1005 #ifndef PRODUCT
1006  public:
1007   enum {
1008     jump_ring_buffer_size = 16
1009   };
1010  private:  // restore original namespace restriction
1011 #endif
1012 
1013   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
1014 
1015   ThreadFunction _entry_point;
1016 
1017   JNIEnv        _jni_environment;
1018 
1019   // Deopt support
1020   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
1021 
1022   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
1023                                                  // transition out of native
1024   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
1025   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
1026   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
1027   // Because deoptimization is lazy we must save jvmti requests to set locals
1028   // in compiled frames until we deoptimize and we have an interpreter frame.
1029   // This holds the pointer to array (yeah like there might be more than one) of
1030   // description of compiled vframes that have locals that need to be updated.
1031   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
1032 
1033   // Handshake value for fixing 6243940. We need a place for the i2c
1034   // adapter to store the callee Method*. This value is NEVER live
1035   // across a gc point so it does NOT have to be gc'd
1036   // The handshake is open ended since we can't be certain that it will
1037   // be NULLed. This is because we rarely ever see the race and end up
1038   // in handle_wrong_method which is the backend of the handshake. See
1039   // code in i2c adapters and handle_wrong_method.
1040 
1041   Method*       _callee_target;
1042 
1043   // Used to pass back results to the interpreter or generated code running Java code.
1044   oop           _vm_result;    // oop result is GC-preserved
1045   Metadata*     _vm_result_2;  // non-oop result
1046   oop           _return_buffered_value; // buffered value being returned
1047 
1048   // See ReduceInitialCardMarks: this holds the precise space interval of
1049   // the most recent slow path allocation for which compiled code has
1050   // elided card-marks for performance along the fast-path.
1051   MemRegion     _deferred_card_mark;
1052 
1053   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
1054                                                  // allocated during deoptimization
1055                                                  // and by JNI_MonitorEnter/Exit
1056 
1057   // Async. requests support
1058   enum AsyncRequests {
1059     _no_async_condition = 0,
1060     _async_exception,
1061     _async_unsafe_access_error
1062   };
1063   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1064   oop           _pending_async_exception;
1065 
1066   // Safepoint support
1067  public:                                         // Expose _thread_state for SafeFetchInt()
1068   volatile JavaThreadState _thread_state;
1069  private:
1070   ThreadSafepointState* _safepoint_state;        // Holds information about a thread during a safepoint
1071   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
1072 
1073   // JavaThread termination support
1074   enum TerminatedTypes {
1075     _not_terminated = 0xDEAD - 2,
1076     _thread_exiting,                             // JavaThread::exit() has been called for this thread
1077     _thread_terminated,                          // JavaThread is removed from thread list
1078     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
1079                                                  // only VM_Exit can set _vm_exited
1080   };
1081 
1082   // In general a JavaThread's _terminated field transitions as follows:
1083   //
1084   //   _not_terminated => _thread_exiting => _thread_terminated
1085   //
1086   // _vm_exited is a special value to cover the case of a JavaThread
1087   // executing native code after the VM itself is terminated.
1088   volatile TerminatedTypes _terminated;
1089   // suspend/resume support
1090   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1091   jint                  _in_deopt_handler;       // count of deoptimization
1092                                                  // handlers thread is in
1093   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1094   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1095                                                          // never locked) when throwing an exception. Used by interpreter only.
1096 
1097   // JNI attach states:
1098   enum JNIAttachStates {
1099     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1100     _attaching_via_jni,          // thread is attaching via JNI
1101     _attached_via_jni            // thread has attached via JNI
1102   };
1103 
1104   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1105   // A native thread that is attaching via JNI starts with a value
1106   // of _attaching_via_jni and transitions to _attached_via_jni.
1107   volatile JNIAttachStates _jni_attach_state;
1108 
1109  public:
1110   // State of the stack guard pages for this thread.
1111   enum StackGuardState {
1112     stack_guard_unused,         // not needed
1113     stack_guard_reserved_disabled,
1114     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1115     stack_guard_enabled         // enabled
1116   };
1117 
1118  private:
1119 
1120 #if INCLUDE_JVMCI
1121   // The _pending_* fields below are used to communicate extra information
1122   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1123 
1124   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1125   int       _pending_deoptimization;
1126 
1127   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1128   // before the monitor has been acquired.
1129   bool      _pending_monitorenter;
1130 
1131   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1132   bool      _pending_transfer_to_interpreter;
1133 
1134   // True if in a runtime call from compiled code that will deoptimize
1135   // and re-execute a failed heap allocation in the interpreter.
1136   bool      _in_retryable_allocation;
1137 
1138   // An id of a speculation that JVMCI compiled code can use to further describe and
1139   // uniquely identify the  speculative optimization guarded by the uncommon trap
1140   jlong     _pending_failed_speculation;
1141 
1142   // These fields are mutually exclusive in terms of live ranges.
1143   union {
1144     // Communicates the pc at which the most recent implicit exception occurred
1145     // from the signal handler to a deoptimization stub.
1146     address   _implicit_exception_pc;
1147 
1148     // Communicates an alternative call target to an i2c stub from a JavaCall .
1149     address   _alternate_call_target;
1150   } _jvmci;
1151 
1152   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1153   jlong*    _jvmci_counters;
1154 
1155  public:
1156   static jlong* _jvmci_old_thread_counters;
1157   static void collect_counters(jlong* array, int length);
1158 
1159   bool resize_counters(int current_size, int new_size);
1160 
1161   static bool resize_all_jvmci_counters(int new_size);
1162 
1163  private:
1164 #endif // INCLUDE_JVMCI
1165 
1166   StackGuardState  _stack_guard_state;
1167 
1168   // Precompute the limit of the stack as used in stack overflow checks.
1169   // We load it from here to simplify the stack overflow check in assembly.
1170   address          _stack_overflow_limit;
1171   address          _reserved_stack_activation;
1172 
1173   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1174   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1175   // code)
1176   volatile oop     _exception_oop;               // Exception thrown in compiled code
1177   volatile address _exception_pc;                // PC where exception happened
1178   volatile address _exception_handler_pc;        // PC for handler of exception
1179   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1180 
1181  private:
1182   // support for JNI critical regions
1183   jint    _jni_active_critical;                  // count of entries into JNI critical region
1184 
1185   // Checked JNI: function name requires exception check
1186   char* _pending_jni_exception_check_fn;
1187 
1188   // For deadlock detection.
1189   int _depth_first_number;
1190 
1191   // JVMTI PopFrame support
1192   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1193   int _popframe_condition;
1194 
1195   // If reallocation of scalar replaced objects fails, we throw OOM
1196   // and during exception propagation, pop the top
1197   // _frames_to_pop_failed_realloc frames, the ones that reference
1198   // failed reallocations.
1199   int _frames_to_pop_failed_realloc;
1200 
1201 #ifndef PRODUCT
1202   int _jmp_ring_index;
1203   struct {
1204     // We use intptr_t instead of address so debugger doesn't try and display strings
1205     intptr_t _target;
1206     intptr_t _instruction;
1207     const char*  _file;
1208     int _line;
1209   }   _jmp_ring[jump_ring_buffer_size];
1210 #endif // PRODUCT
1211 
1212   friend class VMThread;
1213   friend class ThreadWaitTransition;
1214   friend class VM_Exit;
1215 
1216   void initialize();                             // Initialized the instance variables
1217 
1218  public:
1219   // Constructor
1220   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1221   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1222   ~JavaThread();
1223 
1224 #ifdef ASSERT
1225   // verify this JavaThread hasn't be published in the Threads::list yet
1226   void verify_not_published();
1227 #endif
1228 
1229   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1230   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1231     _jni_environment.functions = functionTable;
1232   }
1233   struct JNINativeInterface_* get_jni_functions() {
1234     return (struct JNINativeInterface_ *)_jni_environment.functions;
1235   }
1236 
1237   // This function is called at thread creation to allow
1238   // platform specific thread variables to be initialized.
1239   void cache_global_variables();
1240 
1241   // Executes Shutdown.shutdown()
1242   void invoke_shutdown_hooks();
1243 
1244   // Cleanup on thread exit
1245   enum ExitType {
1246     normal_exit,
1247     jni_detach
1248   };
1249   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1250 
1251   void cleanup_failed_attach_current_thread(bool is_daemon);
1252 
1253   // Testers
1254   virtual bool is_Java_thread() const            { return true;  }
1255   virtual bool can_call_java() const             { return true; }
1256 
1257   // Thread oop. threadObj() can be NULL for initial JavaThread
1258   // (or for threads attached via JNI)
1259   oop threadObj() const                          { return _threadObj; }
1260   void set_threadObj(oop p)                      { _threadObj = p; }
1261 
1262   ThreadPriority java_priority() const;          // Read from threadObj()
1263 
1264   // Prepare thread and add to priority queue.  If a priority is
1265   // not specified, use the priority of the thread object. Threads_lock
1266   // must be held while this function is called.
1267   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1268 
1269   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1270   address saved_exception_pc()                   { return _saved_exception_pc; }
1271 
1272 
1273   ThreadFunction entry_point() const             { return _entry_point; }
1274 
1275   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1276   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1277 
1278   // Last frame anchor routines
1279 
1280   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1281 
1282   // last_Java_sp
1283   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1284   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1285 
1286   // last_Java_pc
1287 
1288   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1289 
1290   // Safepoint support
1291   inline JavaThreadState thread_state() const;
1292   inline void set_thread_state(JavaThreadState s);
1293   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
1294   inline ThreadSafepointState* safepoint_state() const;
1295   inline void set_safepoint_state(ThreadSafepointState* state);
1296   inline bool is_at_poll_safepoint();
1297 
1298   // JavaThread termination and lifecycle support:
1299   void smr_delete();
1300   bool on_thread_list() const { return _on_thread_list; }
1301   void set_on_thread_list() { _on_thread_list = true; }
1302 
1303   // thread has called JavaThread::exit() or is terminated
1304   bool is_exiting() const;
1305   // thread is terminated (no longer on the threads list); we compare
1306   // against the two non-terminated values so that a freed JavaThread
1307   // will also be considered terminated.
1308   bool check_is_terminated(TerminatedTypes l_terminated) const {
1309     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1310   }
1311   bool is_terminated() const;
1312   void set_terminated(TerminatedTypes t);
1313   // special for Threads::remove() which is static:
1314   void set_terminated_value();
1315   void block_if_vm_exited();
1316 
1317   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1318   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1319 
1320   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1321   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1322 
1323   inline void set_polling_page_release(void* poll_value);
1324   inline void set_polling_page(void* poll_value);
1325   inline volatile void* get_polling_page();
1326 
1327  private:
1328   // Support for thread handshake operations
1329   HandshakeState _handshake;
1330  public:
1331   void set_handshake_operation(HandshakeOperation* op) {
1332     _handshake.set_operation(this, op);
1333   }
1334 
1335   bool has_handshake() const {
1336     return _handshake.has_operation();
1337   }
1338 
1339   void handshake_process_by_self() {
1340     _handshake.process_by_self(this);
1341   }
1342 
1343   void handshake_process_by_vmthread() {
1344     _handshake.process_by_vmthread(this);
1345   }
1346 
1347   // Suspend/resume support for JavaThread
1348  private:
1349   inline void set_ext_suspended();
1350   inline void clear_ext_suspended();
1351 
1352  public:
1353   void java_suspend(); // higher-level suspension logic called by the public APIs
1354   void java_resume();  // higher-level resume logic called by the public APIs
1355   int  java_suspend_self(); // low-level self-suspension mechanics
1356 
1357  private:
1358   // mid-level wrapper around java_suspend_self to set up correct state and
1359   // check for a pending safepoint at the end
1360   void java_suspend_self_with_safepoint_check();
1361 
1362  public:
1363   void check_and_wait_while_suspended() {
1364     assert(JavaThread::current() == this, "sanity check");
1365 
1366     bool do_self_suspend;
1367     do {
1368       // were we externally suspended while we were waiting?
1369       do_self_suspend = handle_special_suspend_equivalent_condition();
1370       if (do_self_suspend) {
1371         // don't surprise the thread that suspended us by returning
1372         java_suspend_self();
1373         set_suspend_equivalent();
1374       }
1375     } while (do_self_suspend);
1376   }
1377   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1378   // Check for async exception in addition to safepoint and suspend request.
1379   static void check_special_condition_for_native_trans(JavaThread *thread);
1380 
1381   // Same as check_special_condition_for_native_trans but finishes the
1382   // transition into thread_in_Java mode so that it can potentially
1383   // block.
1384   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1385 
1386   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1387   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1388     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1389     // Warning: is_ext_suspend_completed() may temporarily drop the
1390     // SR_lock to allow the thread to reach a stable thread state if
1391     // it is currently in a transient thread state.
1392     return is_ext_suspend_completed(false /* !called_by_wait */,
1393                                     SuspendRetryDelay, bits);
1394   }
1395 
1396   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1397   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1398   // passed as the count and delay parameters. Experiments with specific
1399   // calls to wait_for_ext_suspend_completion() can be done by passing
1400   // other values in the code. Experiments with all calls can be done
1401   // via the appropriate -XX options.
1402   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1403 
1404   // test for suspend - most (all?) of these should go away
1405   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1406 
1407   inline void set_external_suspend();
1408   inline void clear_external_suspend();
1409 
1410   bool is_external_suspend() const {
1411     return (_suspend_flags & _external_suspend) != 0;
1412   }
1413   // Whenever a thread transitions from native to vm/java it must suspend
1414   // if external|deopt suspend is present.
1415   bool is_suspend_after_native() const {
1416     return (_suspend_flags & (_external_suspend JFR_ONLY(| _trace_flag))) != 0;
1417   }
1418 
1419   // external suspend request is completed
1420   bool is_ext_suspended() const {
1421     return (_suspend_flags & _ext_suspended) != 0;
1422   }
1423 
1424   bool is_external_suspend_with_lock() const {
1425     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1426     return is_external_suspend();
1427   }
1428 
1429   // Special method to handle a pending external suspend request
1430   // when a suspend equivalent condition lifts.
1431   bool handle_special_suspend_equivalent_condition() {
1432     assert(is_suspend_equivalent(),
1433            "should only be called in a suspend equivalence condition");
1434     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1435     bool ret = is_external_suspend();
1436     if (!ret) {
1437       // not about to self-suspend so clear suspend equivalence
1438       clear_suspend_equivalent();
1439     }
1440     // implied else:
1441     // We have a pending external suspend request so we leave the
1442     // suspend_equivalent flag set until java_suspend_self() sets
1443     // the ext_suspended flag and clears the suspend_equivalent
1444     // flag. This insures that wait_for_ext_suspend_completion()
1445     // will return consistent values.
1446     return ret;
1447   }
1448 
1449   // utility methods to see if we are doing some kind of suspension
1450   bool is_being_ext_suspended() const            {
1451     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1452     return is_ext_suspended() || is_external_suspend();
1453   }
1454 
1455   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1456 
1457   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1458   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1459 
1460   // Thread.stop support
1461   void send_thread_stop(oop throwable);
1462   AsyncRequests clear_special_runtime_exit_condition() {
1463     AsyncRequests x = _special_runtime_exit_condition;
1464     _special_runtime_exit_condition = _no_async_condition;
1465     return x;
1466   }
1467 
1468   // Are any async conditions present?
1469   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1470 
1471   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1472 
1473   // these next two are also used for self-suspension and async exception support
1474   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1475 
1476   // Return true if JavaThread has an asynchronous condition or
1477   // if external suspension is requested.
1478   bool has_special_runtime_exit_condition() {
1479     // Because we don't use is_external_suspend_with_lock
1480     // it is possible that we won't see an asynchronous external suspend
1481     // request that has just gotten started, i.e., SR_lock grabbed but
1482     // _external_suspend field change either not made yet or not visible
1483     // yet. However, this is okay because the request is asynchronous and
1484     // we will see the new flag value the next time through. It's also
1485     // possible that the external suspend request is dropped after
1486     // we have checked is_external_suspend(), we will recheck its value
1487     // under SR_lock in java_suspend_self().
1488     return (_special_runtime_exit_condition != _no_async_condition) ||
1489             is_external_suspend() || is_trace_suspend();
1490   }
1491 
1492   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1493 
1494   inline void set_pending_async_exception(oop e);
1495 
1496   // Fast-locking support
1497   bool is_lock_owned(address adr) const;
1498 
1499   // Accessors for vframe array top
1500   // The linked list of vframe arrays are sorted on sp. This means when we
1501   // unpack the head must contain the vframe array to unpack.
1502   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1503   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1504 
1505   // Side structure for deferring update of java frame locals until deopt occurs
1506   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1507   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1508 
1509   // These only really exist to make debugging deopt problems simpler
1510 
1511   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1512   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1513 
1514   // The special resourceMark used during deoptimization
1515 
1516   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1517   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1518 
1519   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1520   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1521   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1522 
1523   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1524   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1525 
1526   Method*    callee_target() const               { return _callee_target; }
1527   void set_callee_target  (Method* x)          { _callee_target   = x; }
1528 
1529   // Oop results of vm runtime calls
1530   oop  vm_result() const                         { return _vm_result; }
1531   void set_vm_result  (oop x)                    { _vm_result   = x; }
1532 
1533   Metadata*    vm_result_2() const               { return _vm_result_2; }
1534   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1535 
1536   oop return_buffered_value() const              { return _return_buffered_value; }
1537   void set_return_buffered_value(oop val)        { _return_buffered_value = val; }
1538 
1539   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1540   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1541 
1542 #if INCLUDE_JVMCI
1543   int  pending_deoptimization() const             { return _pending_deoptimization; }
1544   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
1545   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1546   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1547   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1548   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
1549   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1550   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1551   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1552 
1553   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
1554   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
1555 #endif // INCLUDE_JVMCI
1556 
1557   // Exception handling for compiled methods
1558   oop      exception_oop() const                 { return _exception_oop; }
1559   address  exception_pc() const                  { return _exception_pc; }
1560   address  exception_handler_pc() const          { return _exception_handler_pc; }
1561   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1562 
1563   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1564   void set_exception_pc(address a)               { _exception_pc = a; }
1565   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1566   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1567 
1568   void clear_exception_oop_and_pc() {
1569     set_exception_oop(NULL);
1570     set_exception_pc(NULL);
1571   }
1572 
1573   // Stack overflow support
1574   //
1575   //  (small addresses)
1576   //
1577   //  --  <-- stack_end()                   ---
1578   //  |                                      |
1579   //  |  red pages                           |
1580   //  |                                      |
1581   //  --  <-- stack_red_zone_base()          |
1582   //  |                                      |
1583   //  |                                     guard
1584   //  |  yellow pages                       zone
1585   //  |                                      |
1586   //  |                                      |
1587   //  --  <-- stack_yellow_zone_base()       |
1588   //  |                                      |
1589   //  |                                      |
1590   //  |  reserved pages                      |
1591   //  |                                      |
1592   //  --  <-- stack_reserved_zone_base()    ---      ---
1593   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1594   //                                                  |   zone
1595   //                                                 \|/  size
1596   //  some untouched memory                          ---
1597   //
1598   //
1599   //  --
1600   //  |
1601   //  |  shadow zone
1602   //  |
1603   //  --
1604   //  x    frame n
1605   //  --
1606   //  x    frame n-1
1607   //  x
1608   //  --
1609   //  ...
1610   //
1611   //  --
1612   //  x    frame 0
1613   //  --  <-- stack_base()
1614   //
1615   //  (large addresses)
1616   //
1617 
1618  private:
1619   // These values are derived from flags StackRedPages, StackYellowPages,
1620   // StackReservedPages and StackShadowPages. The zone size is determined
1621   // ergonomically if page_size > 4K.
1622   static size_t _stack_red_zone_size;
1623   static size_t _stack_yellow_zone_size;
1624   static size_t _stack_reserved_zone_size;
1625   static size_t _stack_shadow_zone_size;
1626  public:
1627   inline size_t stack_available(address cur_sp);
1628 
1629   static size_t stack_red_zone_size() {
1630     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1631     return _stack_red_zone_size;
1632   }
1633   static void set_stack_red_zone_size(size_t s) {
1634     assert(is_aligned(s, os::vm_page_size()),
1635            "We can not protect if the red zone size is not page aligned.");
1636     assert(_stack_red_zone_size == 0, "This should be called only once.");
1637     _stack_red_zone_size = s;
1638   }
1639   address stack_red_zone_base() {
1640     return (address)(stack_end() + stack_red_zone_size());
1641   }
1642   bool in_stack_red_zone(address a) {
1643     return a <= stack_red_zone_base() && a >= stack_end();
1644   }
1645 
1646   static size_t stack_yellow_zone_size() {
1647     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1648     return _stack_yellow_zone_size;
1649   }
1650   static void set_stack_yellow_zone_size(size_t s) {
1651     assert(is_aligned(s, os::vm_page_size()),
1652            "We can not protect if the yellow zone size is not page aligned.");
1653     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1654     _stack_yellow_zone_size = s;
1655   }
1656 
1657   static size_t stack_reserved_zone_size() {
1658     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1659     return _stack_reserved_zone_size;
1660   }
1661   static void set_stack_reserved_zone_size(size_t s) {
1662     assert(is_aligned(s, os::vm_page_size()),
1663            "We can not protect if the reserved zone size is not page aligned.");
1664     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1665     _stack_reserved_zone_size = s;
1666   }
1667   address stack_reserved_zone_base() {
1668     return (address)(stack_end() +
1669                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1670   }
1671   bool in_stack_reserved_zone(address a) {
1672     return (a <= stack_reserved_zone_base()) &&
1673            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1674   }
1675 
1676   static size_t stack_yellow_reserved_zone_size() {
1677     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1678   }
1679   bool in_stack_yellow_reserved_zone(address a) {
1680     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1681   }
1682 
1683   // Size of red + yellow + reserved zones.
1684   static size_t stack_guard_zone_size() {
1685     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1686   }
1687 
1688   static size_t stack_shadow_zone_size() {
1689     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1690     return _stack_shadow_zone_size;
1691   }
1692   static void set_stack_shadow_zone_size(size_t s) {
1693     // The shadow area is not allocated or protected, so
1694     // it needs not be page aligned.
1695     // But the stack bang currently assumes that it is a
1696     // multiple of page size. This guarantees that the bang
1697     // loop touches all pages in the shadow zone.
1698     // This can be guaranteed differently, as well.  E.g., if
1699     // the page size is a multiple of 4K, banging in 4K steps
1700     // suffices to touch all pages. (Some pages are banged
1701     // several times, though.)
1702     assert(is_aligned(s, os::vm_page_size()),
1703            "Stack bang assumes multiple of page size.");
1704     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1705     _stack_shadow_zone_size = s;
1706   }
1707 
1708   void create_stack_guard_pages();
1709   void remove_stack_guard_pages();
1710 
1711   void enable_stack_reserved_zone();
1712   void disable_stack_reserved_zone();
1713   void enable_stack_yellow_reserved_zone();
1714   void disable_stack_yellow_reserved_zone();
1715   void enable_stack_red_zone();
1716   void disable_stack_red_zone();
1717 
1718   inline bool stack_guard_zone_unused();
1719   inline bool stack_yellow_reserved_zone_disabled();
1720   inline bool stack_reserved_zone_disabled();
1721   inline bool stack_guards_enabled();
1722 
1723   address reserved_stack_activation() const { return _reserved_stack_activation; }
1724   void set_reserved_stack_activation(address addr) {
1725     assert(_reserved_stack_activation == stack_base()
1726             || _reserved_stack_activation == NULL
1727             || addr == stack_base(), "Must not be set twice");
1728     _reserved_stack_activation = addr;
1729   }
1730 
1731   // Attempt to reguard the stack after a stack overflow may have occurred.
1732   // Returns true if (a) guard pages are not needed on this thread, (b) the
1733   // pages are already guarded, or (c) the pages were successfully reguarded.
1734   // Returns false if there is not enough stack space to reguard the pages, in
1735   // which case the caller should unwind a frame and try again.  The argument
1736   // should be the caller's (approximate) sp.
1737   bool reguard_stack(address cur_sp);
1738   // Similar to above but see if current stackpoint is out of the guard area
1739   // and reguard if possible.
1740   bool reguard_stack(void);
1741 
1742   address stack_overflow_limit() { return _stack_overflow_limit; }
1743   void set_stack_overflow_limit() {
1744     _stack_overflow_limit =
1745       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1746   }
1747 
1748   // Misc. accessors/mutators
1749   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1750   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1751   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1752 
1753 #ifndef PRODUCT
1754   void record_jump(address target, address instr, const char* file, int line);
1755 #endif // PRODUCT
1756 
1757   // For assembly stub generation
1758   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1759 #ifndef PRODUCT
1760   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1761   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1762 #endif // PRODUCT
1763   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1764   static ByteSize pending_jni_exception_check_fn_offset() {
1765     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1766   }
1767   static ByteSize last_Java_sp_offset() {
1768     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1769   }
1770   static ByteSize last_Java_pc_offset() {
1771     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1772   }
1773   static ByteSize frame_anchor_offset() {
1774     return byte_offset_of(JavaThread, _anchor);
1775   }
1776   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1777   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1778   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1779   static ByteSize return_buffered_value_offset() { return byte_offset_of(JavaThread, _return_buffered_value); }
1780   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1781   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1782   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1783 #if INCLUDE_JVMCI
1784   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1785   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1786   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1787   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1788   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1789   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1790 #endif // INCLUDE_JVMCI
1791   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1792   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1793   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1794   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1795   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1796   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1797   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1798   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1799 
1800   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1801   static ByteSize should_post_on_exceptions_flag_offset() {
1802     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1803   }
1804 
1805   // Returns the jni environment for this thread
1806   JNIEnv* jni_environment()                      { return &_jni_environment; }
1807 
1808   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1809     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1810     // Only return NULL if thread is off the thread list; starting to
1811     // exit should not return NULL.
1812     if (thread_from_jni_env->is_terminated()) {
1813       thread_from_jni_env->block_if_vm_exited();
1814       return NULL;
1815     } else {
1816       return thread_from_jni_env;
1817     }
1818   }
1819 
1820   // JNI critical regions. These can nest.
1821   bool in_critical()    { return _jni_active_critical > 0; }
1822   bool in_last_critical()  { return _jni_active_critical == 1; }
1823   inline void enter_critical();
1824   void exit_critical() {
1825     assert(Thread::current() == this, "this must be current thread");
1826     _jni_active_critical--;
1827     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1828   }
1829 
1830   // Checked JNI: is the programmer required to check for exceptions, if so specify
1831   // which function name. Returning to a Java frame should implicitly clear the
1832   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1833   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1834   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1835   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1836   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1837   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1838   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1839 
1840   // For deadlock detection
1841   int depth_first_number() { return _depth_first_number; }
1842   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1843 
1844  private:
1845   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1846 
1847  public:
1848   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1849   void add_monitor_chunk(MonitorChunk* chunk);
1850   void remove_monitor_chunk(MonitorChunk* chunk);
1851   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1852   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1853   void dec_in_deopt_handler() {
1854     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1855     if (_in_deopt_handler > 0) { // robustness
1856       _in_deopt_handler--;
1857     }
1858   }
1859 
1860  private:
1861   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1862 
1863  public:
1864 
1865   // Frame iteration; calls the function f for all frames on the stack
1866   void frames_do(void f(frame*, const RegisterMap*));
1867 
1868   // Memory operations
1869   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1870 
1871   // Sweeper operations
1872   virtual void nmethods_do(CodeBlobClosure* cf);
1873 
1874   // RedefineClasses Support
1875   void metadata_do(MetadataClosure* f);
1876 
1877   // Debug method asserting thread states are correct during a handshake operation.
1878   DEBUG_ONLY(void verify_states_for_handshake();)
1879 
1880   // Misc. operations
1881   char* name() const { return (char*)get_thread_name(); }
1882   void print_on(outputStream* st, bool print_extended_info) const;
1883   void print_on(outputStream* st) const { print_on(st, false); }
1884   void print() const;
1885   void print_value();
1886   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1887   void print_thread_state() const                      PRODUCT_RETURN;
1888   void print_on_error(outputStream* st, char* buf, int buflen) const;
1889   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1890   void verify();
1891   const char* get_thread_name() const;
1892  protected:
1893   // factor out low-level mechanics for use in both normal and error cases
1894   virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1895  public:
1896   const char* get_threadgroup_name() const;
1897   const char* get_parent_name() const;
1898 
1899   // Accessing frames
1900   frame last_frame() {
1901     _anchor.make_walkable(this);
1902     return pd_last_frame();
1903   }
1904   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1905 
1906   // Returns method at 'depth' java or native frames down the stack
1907   // Used for security checks
1908   Klass* security_get_caller_class(int depth);
1909 
1910   // Print stack trace in external format
1911   void print_stack_on(outputStream* st);
1912   void print_stack() { print_stack_on(tty); }
1913 
1914   // Print stack traces in various internal formats
1915   void trace_stack()                             PRODUCT_RETURN;
1916   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1917   void trace_frames()                            PRODUCT_RETURN;
1918   void trace_oops()                              PRODUCT_RETURN;
1919 
1920   // Print an annotated view of the stack frames
1921   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1922   void validate_frame_layout() {
1923     print_frame_layout(0, true);
1924   }
1925 
1926   // Returns the number of stack frames on the stack
1927   int depth() const;
1928 
1929   // Function for testing deoptimization
1930   void deoptimize();
1931   void make_zombies();
1932 
1933   void deoptimize_marked_methods(bool in_handshake);
1934 
1935  public:
1936   // Returns the running thread as a JavaThread
1937   static inline JavaThread* current();
1938 
1939   // Returns the active Java thread.  Do not use this if you know you are calling
1940   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1941   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1942   // operation.  You may not want that either.
1943   static JavaThread* active();
1944 
1945   inline CompilerThread* as_CompilerThread();
1946 
1947  protected:
1948   virtual void pre_run();
1949   virtual void run();
1950   void thread_main_inner();
1951   virtual void post_run();
1952 
1953 
1954  private:
1955   GrowableArray<oop>* _array_for_gc;
1956  public:
1957 
1958   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1959 
1960  public:
1961   // Thread local information maintained by JVMTI.
1962   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1963   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1964   // getter is used to get this JavaThread's JvmtiThreadState if it has
1965   // one which means NULL can be returned. JvmtiThreadState::state_for()
1966   // is used to get the specified JavaThread's JvmtiThreadState if it has
1967   // one or it allocates a new JvmtiThreadState for the JavaThread and
1968   // returns it. JvmtiThreadState::state_for() will return NULL only if
1969   // the specified JavaThread is exiting.
1970   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1971   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1972 
1973   // JVMTI PopFrame support
1974   // Setting and clearing popframe_condition
1975   // All of these enumerated values are bits. popframe_pending
1976   // indicates that a PopFrame() has been requested and not yet been
1977   // completed. popframe_processing indicates that that PopFrame() is in
1978   // the process of being completed. popframe_force_deopt_reexecution_bit
1979   // indicates that special handling is required when returning to a
1980   // deoptimized caller.
1981   enum PopCondition {
1982     popframe_inactive                      = 0x00,
1983     popframe_pending_bit                   = 0x01,
1984     popframe_processing_bit                = 0x02,
1985     popframe_force_deopt_reexecution_bit   = 0x04
1986   };
1987   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1988   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1989   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1990   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1991   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1992   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1993   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1994   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1995 #ifdef CC_INTERP
1996   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1997   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1998   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1999   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
2000   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
2001 #endif
2002 
2003   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
2004   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
2005   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
2006 
2007  private:
2008   // Saved incoming arguments to popped frame.
2009   // Used only when popped interpreted frame returns to deoptimized frame.
2010   void*    _popframe_preserved_args;
2011   int      _popframe_preserved_args_size;
2012 
2013  public:
2014   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
2015   void* popframe_preserved_args();
2016   ByteSize popframe_preserved_args_size();
2017   WordSize popframe_preserved_args_size_in_words();
2018   void  popframe_free_preserved_args();
2019 
2020 
2021  private:
2022   JvmtiThreadState *_jvmti_thread_state;
2023 
2024   // Used by the interpreter in fullspeed mode for frame pop, method
2025   // entry, method exit and single stepping support. This field is
2026   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
2027   // It can be set to zero asynchronously (i.e., without a VM operation
2028   // or a lock) so we have to be very careful.
2029   int               _interp_only_mode;
2030 
2031  public:
2032   // used by the interpreter for fullspeed debugging support (see above)
2033   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2034   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
2035   int get_interp_only_mode()                { return _interp_only_mode; }
2036   void increment_interp_only_mode()         { ++_interp_only_mode; }
2037   void decrement_interp_only_mode()         { --_interp_only_mode; }
2038 
2039   // support for cached flag that indicates whether exceptions need to be posted for this thread
2040   // if this is false, we can avoid deoptimizing when events are thrown
2041   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2042  private:
2043   int    _should_post_on_exceptions_flag;
2044 
2045  public:
2046   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
2047   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
2048 
2049  private:
2050   ThreadStatistics *_thread_stat;
2051 
2052  public:
2053   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
2054 
2055   // Return a blocker object for which this thread is blocked parking.
2056   oop current_park_blocker();
2057 
2058  private:
2059   static size_t _stack_size_at_create;
2060 
2061  public:
2062   static inline size_t stack_size_at_create(void) {
2063     return _stack_size_at_create;
2064   }
2065   static inline void set_stack_size_at_create(size_t value) {
2066     _stack_size_at_create = value;
2067   }
2068 
2069   // Machine dependent stuff
2070 #include OS_CPU_HEADER(thread)
2071 
2072  public:
2073   void set_blocked_on_compilation(bool value) {
2074     _blocked_on_compilation = value;
2075   }
2076 
2077   bool blocked_on_compilation() {
2078     return _blocked_on_compilation;
2079   }
2080  protected:
2081   bool         _blocked_on_compilation;
2082 
2083 
2084   // JSR166 per-thread parker
2085  private:
2086   Parker*    _parker;
2087  public:
2088   Parker*     parker() { return _parker; }
2089 
2090   // Biased locking support
2091  private:
2092   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2093  public:
2094   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2095   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2096 
2097   // clearing/querying jni attach status
2098   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2099   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2100   inline void set_done_attaching_via_jni();
2101 
2102   // Stack dump assistance:
2103   // Track the class we want to initialize but for which we have to wait
2104   // on its init_lock() because it is already being initialized.
2105   void set_class_to_be_initialized(InstanceKlass* k);
2106   InstanceKlass* class_to_be_initialized() const;
2107 
2108 private:
2109   InstanceKlass* _class_to_be_initialized;
2110 
2111 };
2112 
2113 // Inline implementation of JavaThread::current
2114 inline JavaThread* JavaThread::current() {
2115   Thread* thread = Thread::current();
2116   assert(thread->is_Java_thread(), "just checking");
2117   return (JavaThread*)thread;
2118 }
2119 
2120 inline CompilerThread* JavaThread::as_CompilerThread() {
2121   assert(is_Compiler_thread(), "just checking");
2122   return (CompilerThread*)this;
2123 }
2124 
2125 // Dedicated thread to sweep the code cache
2126 class CodeCacheSweeperThread : public JavaThread {
2127   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2128  public:
2129   CodeCacheSweeperThread();
2130   // Track the nmethod currently being scanned by the sweeper
2131   void set_scanned_compiled_method(CompiledMethod* cm) {
2132     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2133     _scanned_compiled_method = cm;
2134   }
2135 
2136   // Hide sweeper thread from external view.
2137   bool is_hidden_from_external_view() const { return true; }
2138 
2139   bool is_Code_cache_sweeper_thread() const { return true; }
2140 
2141   // Prevent GC from unloading _scanned_compiled_method
2142   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2143   void nmethods_do(CodeBlobClosure* cf);
2144 };
2145 
2146 // A thread used for Compilation.
2147 class CompilerThread : public JavaThread {
2148   friend class VMStructs;
2149  private:
2150   CompilerCounters* _counters;
2151 
2152   ciEnv*                _env;
2153   CompileLog*           _log;
2154   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2155   CompileQueue*         _queue;
2156   BufferBlob*           _buffer_blob;
2157 
2158   AbstractCompiler*     _compiler;
2159   TimeStamp             _idle_time;
2160 
2161  public:
2162 
2163   static CompilerThread* current();
2164 
2165   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2166   ~CompilerThread();
2167 
2168   bool is_Compiler_thread() const                { return true; }
2169 
2170   virtual bool can_call_java() const;
2171 
2172   // Hide native compiler threads from external view.
2173   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2174 
2175   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2176   AbstractCompiler* compiler() const             { return _compiler; }
2177 
2178   CompileQueue* queue()        const             { return _queue; }
2179   CompilerCounters* counters() const             { return _counters; }
2180 
2181   // Get/set the thread's compilation environment.
2182   ciEnv*        env()                            { return _env; }
2183   void          set_env(ciEnv* env)              { _env = env; }
2184 
2185   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2186   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2187 
2188   // Get/set the thread's logging information
2189   CompileLog*   log()                            { return _log; }
2190   void          init_log(CompileLog* log) {
2191     // Set once, for good.
2192     assert(_log == NULL, "set only once");
2193     _log = log;
2194   }
2195 
2196   void start_idle_timer()                        { _idle_time.update(); }
2197   jlong idle_time_millis() {
2198     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2199   }
2200 
2201 #ifndef PRODUCT
2202  private:
2203   IdealGraphPrinter *_ideal_graph_printer;
2204  public:
2205   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2206   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2207 #endif
2208 
2209   // Get/set the thread's current task
2210   CompileTask* task()                      { return _task; }
2211   void         set_task(CompileTask* task) { _task = task; }
2212 };
2213 
2214 inline CompilerThread* CompilerThread::current() {
2215   return JavaThread::current()->as_CompilerThread();
2216 }
2217 
2218 // The active thread queue. It also keeps track of the current used
2219 // thread priorities.
2220 class Threads: AllStatic {
2221   friend class VMStructs;
2222  private:
2223   static int         _number_of_threads;
2224   static int         _number_of_non_daemon_threads;
2225   static int         _return_code;
2226   static uintx       _thread_claim_token;
2227 #ifdef ASSERT
2228   static bool        _vm_complete;
2229 #endif
2230 
2231   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2232   static void initialize_jsr292_core_classes(TRAPS);
2233 
2234  public:
2235   // Thread management
2236   // force_daemon is a concession to JNI, where we may need to add a
2237   // thread to the thread list before allocating its thread object
2238   static void add(JavaThread* p, bool force_daemon = false);
2239   static void remove(JavaThread* p, bool is_daemon);
2240   static void non_java_threads_do(ThreadClosure* tc);
2241   static void java_threads_do(ThreadClosure* tc);
2242   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2243   static void threads_do(ThreadClosure* tc);
2244   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2245 
2246   // Initializes the vm and creates the vm thread
2247   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2248   static void convert_vm_init_libraries_to_agents();
2249   static void create_vm_init_libraries();
2250   static void create_vm_init_agents();
2251   static void shutdown_vm_agents();
2252   static bool destroy_vm();
2253   // Supported VM versions via JNI
2254   // Includes JNI_VERSION_1_1
2255   static jboolean is_supported_jni_version_including_1_1(jint version);
2256   // Does not include JNI_VERSION_1_1
2257   static jboolean is_supported_jni_version(jint version);
2258 
2259   // The "thread claim token" provides a way for threads to be claimed
2260   // by parallel worker tasks.
2261   //
2262   // Each thread contains a "token" field. A task will claim the
2263   // thread only if its token is different from the global token,
2264   // which is updated by calling change_thread_claim_token().  When
2265   // a thread is claimed, it's token is set to the global token value
2266   // so other threads in the same iteration pass won't claim it.
2267   //
2268   // For this to work change_thread_claim_token() needs to be called
2269   // exactly once in sequential code before starting parallel tasks
2270   // that should claim threads.
2271   //
2272   // New threads get their token set to 0 and change_thread_claim_token()
2273   // never sets the global token to 0.
2274   static uintx thread_claim_token() { return _thread_claim_token; }
2275   static void change_thread_claim_token();
2276   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2277 
2278   // Apply "f->do_oop" to all root oops in all threads.
2279   // This version may only be called by sequential code.
2280   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2281   // This version may be called by sequential or parallel code.
2282   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2283 
2284   // Apply "f->do_oop" to roots in all threads that
2285   // are part of compiled frames
2286   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2287 
2288   static void convert_hcode_pointers();
2289   static void restore_hcode_pointers();
2290 
2291   // Sweeper
2292   static void nmethods_do(CodeBlobClosure* cf);
2293 
2294   // RedefineClasses support
2295   static void metadata_do(MetadataClosure* f);
2296   static void metadata_handles_do(void f(Metadata*));
2297 
2298 #ifdef ASSERT
2299   static bool is_vm_complete() { return _vm_complete; }
2300 #endif // ASSERT
2301 
2302   // Verification
2303   static void verify();
2304   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2305   static void print(bool print_stacks, bool internal_format) {
2306     // this function is only used by debug.cpp
2307     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2308   }
2309   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2310   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2311                              int buflen, bool* found_current);
2312   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2313 
2314   // Get Java threads that are waiting to enter a monitor.
2315   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2316                                                          int count, address monitor);
2317 
2318   // Get owning Java thread from the monitor's owner field.
2319   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2320                                                       address owner);
2321 
2322   // Number of threads on the active threads list
2323   static int number_of_threads()                 { return _number_of_threads; }
2324   // Number of non-daemon threads on the active threads list
2325   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2326 
2327   // Deoptimizes all frames tied to marked nmethods
2328   static void deoptimized_wrt_marked_nmethods();
2329 
2330   struct Test;                  // For private gtest access.
2331 };
2332 
2333 
2334 // Thread iterator
2335 class ThreadClosure: public StackObj {
2336  public:
2337   virtual void do_thread(Thread* thread) = 0;
2338 };
2339 
2340 class SignalHandlerMark: public StackObj {
2341  private:
2342   Thread* _thread;
2343  public:
2344   SignalHandlerMark(Thread* t) {
2345     _thread = t;
2346     if (_thread) _thread->enter_signal_handler();
2347   }
2348   ~SignalHandlerMark() {
2349     if (_thread) _thread->leave_signal_handler();
2350     _thread = NULL;
2351   }
2352 };
2353 
2354 
2355 #endif // SHARE_RUNTIME_THREAD_HPP