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