1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_RUNTIME_THREAD_HPP
  26 #define SHARE_RUNTIME_THREAD_HPP
  27 
  28 #include "jni.h"
  29 #include "code/compiledMethod.hpp"
  30 #include "gc/shared/gcThreadLocalData.hpp"
  31 #include "gc/shared/threadLocalAllocBuffer.hpp"
  32 #include "memory/allocation.hpp"
  33 #include "oops/oop.hpp"
  34 #include "prims/jvmtiExport.hpp"
  35 #include "runtime/frame.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/handshake.hpp"
  38 #include "runtime/javaFrameAnchor.hpp"
  39 #include "runtime/jniHandles.hpp"
  40 #include "runtime/mutexLocker.hpp"
  41 #include "runtime/os.hpp"
  42 #include "runtime/osThread.hpp"
  43 #include "runtime/park.hpp"
  44 #include "runtime/stubRoutines.hpp"
  45 #include "runtime/threadHeapSampler.hpp"
  46 #include "runtime/threadLocalStorage.hpp"
  47 #include "runtime/threadStatisticalInfo.hpp"
  48 #include "runtime/unhandledOops.hpp"
  49 #include "utilities/align.hpp"
  50 #include "utilities/exceptions.hpp"
  51 #include "utilities/macros.hpp"
  52 #ifdef ZERO
  53 # include "stack_zero.hpp"
  54 #endif
  55 #if INCLUDE_JFR
  56 #include "jfr/support/jfrThreadExtension.hpp"
  57 #endif
  58 
  59 
  60 class SafeThreadsListPtr;
  61 class ThreadSafepointState;
  62 class ThreadsList;
  63 class ThreadsSMRSupport;
  64 
  65 class JvmtiThreadState;
  66 class ThreadStatistics;
  67 class ConcurrentLocksDump;
  68 class ParkEvent;
  69 class Parker;
  70 class MonitorInfo;
  71 
  72 class ciEnv;
  73 class CompileThread;
  74 class CompileLog;
  75 class CompileTask;
  76 class CompileQueue;
  77 class CompilerCounters;
  78 
  79 class vframeArray;
  80 class vframe;
  81 class javaVFrame;
  82 
  83 class DeoptResourceMark;
  84 class jvmtiDeferredLocalVariableSet;
  85 
  86 class GCTaskQueue;
  87 class ThreadClosure;
  88 class ICRefillVerifier;
  89 class IdealGraphPrinter;
  90 
  91 class JVMCIEnv;
  92 class JVMCIPrimitiveArray;
  93 
  94 class Metadata;
  95 class ResourceArea;
  96 
  97 DEBUG_ONLY(class ResourceMark;)
  98 
  99 class WorkerThread;
 100 
 101 // Class hierarchy
 102 // - Thread
 103 //   - JavaThread
 104 //     - various subclasses eg CompilerThread, ServiceThread
 105 //   - NonJavaThread
 106 //     - NamedThread
 107 //       - VMThread
 108 //       - ConcurrentGCThread
 109 //       - WorkerThread
 110 //         - GangWorker
 111 //         - GCTaskThread
 112 //     - WatcherThread
 113 //     - JfrThreadSampler
 114 //
 115 // All Thread subclasses must be either JavaThread or NonJavaThread.
 116 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 117 // a partially constructed/destroyed Thread.
 118 
 119 // Thread execution sequence and actions:
 120 // All threads:
 121 //  - thread_native_entry  // per-OS native entry point
 122 //    - stack initialization
 123 //    - other OS-level initialization (signal masks etc)
 124 //    - handshake with creating thread (if not started suspended)
 125 //    - this->call_run()  // common shared entry point
 126 //      - shared common initialization
 127 //      - this->pre_run()  // virtual per-thread-type initialization
 128 //      - this->run()      // virtual per-thread-type "main" logic
 129 //      - shared common tear-down
 130 //      - this->post_run()  // virtual per-thread-type tear-down
 131 //      - // 'this' no longer referenceable
 132 //    - OS-level tear-down (minimal)
 133 //    - final logging
 134 //
 135 // For JavaThread:
 136 //   - this->run()  // virtual but not normally overridden
 137 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 138 //       - this->entry_point()  // set differently for each kind of JavaThread
 139 
 140 class Thread: public ThreadShadow {
 141   friend class VMStructs;
 142   friend class JVMCIVMStructs;
 143  private:
 144 
 145 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 146   // Current thread is maintained as a thread-local variable
 147   static THREAD_LOCAL_DECL Thread* _thr_current;
 148 #endif
 149 
 150   // Thread local data area available to the GC. The internal
 151   // structure and contents of this data area is GC-specific.
 152   // Only GC and GC barrier code should access this data area.
 153   GCThreadLocalData _gc_data;
 154 
 155  public:
 156   static ByteSize gc_data_offset() {
 157     return byte_offset_of(Thread, _gc_data);
 158   }
 159 
 160   template <typename T> T* gc_data() {
 161     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 162     return reinterpret_cast<T*>(&_gc_data);
 163   }
 164 
 165   // Exception handling
 166   // (Note: _pending_exception and friends are in ThreadShadow)
 167   //oop       _pending_exception;                // pending exception for current thread
 168   // const char* _exception_file;                   // file information for exception (debugging only)
 169   // int         _exception_line;                   // line information for exception (debugging only)
 170  protected:
 171 
 172   DEBUG_ONLY(static Thread* _starting_thread;)
 173 
 174   // Support for forcing alignment of thread objects for biased locking
 175   void*       _real_malloc_address;
 176 
 177   // JavaThread lifecycle support:
 178   friend class SafeThreadsListPtr;  // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
 179   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 180   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 181   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 182   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 183 
 184   ThreadsList* volatile _threads_hazard_ptr;
 185   SafeThreadsListPtr*   _threads_list_ptr;
 186   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 187   ThreadsList*          get_threads_hazard_ptr();
 188   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 189   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 190     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 191   }
 192   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 193     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 194   }
 195   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 196     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 197   }
 198   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 199   uint _nested_threads_hazard_ptr_cnt;
 200   void dec_nested_threads_hazard_ptr_cnt() {
 201     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 202     _nested_threads_hazard_ptr_cnt--;
 203   }
 204   void inc_nested_threads_hazard_ptr_cnt() {
 205     _nested_threads_hazard_ptr_cnt++;
 206   }
 207   uint nested_threads_hazard_ptr_cnt() {
 208     return _nested_threads_hazard_ptr_cnt;
 209   }
 210 
 211  public:
 212   void* operator new(size_t size) throw() { return allocate(size, true); }
 213   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 214     return allocate(size, false); }
 215   void  operator delete(void* p);
 216 
 217  protected:
 218   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 219  private:
 220 
 221   // ***************************************************************
 222   // Suspend and resume support
 223   // ***************************************************************
 224   //
 225   // VM suspend/resume no longer exists - it was once used for various
 226   // things including safepoints but was deprecated and finally removed
 227   // in Java 7. Because VM suspension was considered "internal" Java-level
 228   // suspension was considered "external", and this legacy naming scheme
 229   // remains.
 230   //
 231   // External suspend/resume requests come from JVM_SuspendThread,
 232   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 233   // ResumeThread. External
 234   // suspend requests cause _external_suspend to be set and external
 235   // resume requests cause _external_suspend to be cleared.
 236   // External suspend requests do not nest on top of other external
 237   // suspend requests. The higher level APIs reject suspend requests
 238   // for already suspended threads.
 239   //
 240   // The external_suspend
 241   // flag is checked by has_special_runtime_exit_condition() and java thread
 242   // will self-suspend when handle_special_runtime_exit_condition() is
 243   // called. Most uses of the _thread_blocked state in JavaThreads are
 244   // considered the same as being externally suspended; if the blocking
 245   // condition lifts, the JavaThread will self-suspend. Other places
 246   // where VM checks for external_suspend include:
 247   //   + mutex granting (do not enter monitors when thread is suspended)
 248   //   + state transitions from _thread_in_native
 249   //
 250   // In general, java_suspend() does not wait for an external suspend
 251   // request to complete. When it returns, the only guarantee is that
 252   // the _external_suspend field is true.
 253   //
 254   // wait_for_ext_suspend_completion() is used to wait for an external
 255   // suspend request to complete. External suspend requests are usually
 256   // followed by some other interface call that requires the thread to
 257   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 258   // the interface that requires quiescence, we give the JavaThread a
 259   // chance to self-suspend before we need it to be quiescent. This
 260   // improves overall suspend/query performance.
 261   //
 262   // _suspend_flags controls the behavior of java_ suspend/resume.
 263   // It must be set under the protection of SR_lock. Read from the flag is
 264   // OK without SR_lock as long as the value is only used as a hint.
 265   // (e.g., check _external_suspend first without lock and then recheck
 266   // inside SR_lock and finish the suspension)
 267   //
 268   // _suspend_flags is also overloaded for other "special conditions" so
 269   // that a single check indicates whether any special action is needed
 270   // eg. for async exceptions.
 271   // -------------------------------------------------------------------
 272   // Notes:
 273   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 274   // but we still update its value to keep other part of the system (mainly
 275   // JVMTI) happy. ThreadState is legacy code (see notes in
 276   // osThread.hpp).
 277   //
 278   // 2. It would be more natural if set_external_suspend() is private and
 279   // part of java_suspend(), but that probably would affect the suspend/query
 280   // performance. Need more investigation on this.
 281 
 282   // suspend/resume lock: used for self-suspend
 283   Monitor* _SR_lock;
 284 
 285  protected:
 286   enum SuspendFlags {
 287     // NOTE: avoid using the sign-bit as cc generates different test code
 288     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 289 
 290     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 291     _ext_suspended          = 0x40000000U, // thread has self-suspended
 292 
 293     _has_async_exception    = 0x00000001U, // there is a pending async exception
 294     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 295 
 296     _trace_flag             = 0x00000004U  // call tracing backend
 297   };
 298 
 299   // various suspension related flags - atomically updated
 300   // overloaded for async exception checking in check_special_condition_for_native_trans.
 301   volatile uint32_t _suspend_flags;
 302 
 303  private:
 304   int _num_nested_signal;
 305 
 306   DEBUG_ONLY(bool _suspendible_thread;)
 307 
 308  public:
 309   void enter_signal_handler() { _num_nested_signal++; }
 310   void leave_signal_handler() { _num_nested_signal--; }
 311   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 312 
 313   // Determines if a heap allocation failure will be retried
 314   // (e.g., by deoptimizing and re-executing in the interpreter).
 315   // In this case, the failed allocation must raise
 316   // Universe::out_of_memory_error_retry() and omit side effects
 317   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 318   // and -XX:OnOutOfMemoryError.
 319   virtual bool in_retryable_allocation() const { return false; }
 320 
 321 #ifdef ASSERT
 322   void set_suspendible_thread() {
 323     _suspendible_thread = true;
 324   }
 325 
 326   void clear_suspendible_thread() {
 327     _suspendible_thread = false;
 328   }
 329 
 330   bool is_suspendible_thread() { return _suspendible_thread; }
 331 #endif
 332 
 333  private:
 334   // Active_handles points to a block of handles
 335   JNIHandleBlock* _active_handles;
 336 
 337   // One-element thread local free list
 338   JNIHandleBlock* _free_handle_block;
 339 
 340   // Point to the last handle mark
 341   HandleMark* _last_handle_mark;
 342 
 343   // Claim value for parallel iteration over threads.
 344   uintx _threads_do_token;
 345 
 346   // Support for GlobalCounter
 347  private:
 348   volatile uintx _rcu_counter;
 349  public:
 350   volatile uintx* get_rcu_counter() {
 351     return &_rcu_counter;
 352   }
 353 
 354  public:
 355   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 356   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 357  private:
 358 
 359 #ifdef ASSERT
 360   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 361 
 362  public:
 363   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 364     return _missed_ic_stub_refill_verifier;
 365   }
 366 
 367   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 368     _missed_ic_stub_refill_verifier = verifier;
 369   }
 370 #endif // ASSERT
 371 
 372  private:
 373 
 374   // Debug support for checking if code allows safepoints or not.
 375   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 376   // mutex, or blocking on an object synchronizer (Java locking).
 377   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 378   // the above cases.
 379   //
 380   // The class NoSafepointVerifier is used to set this counter.
 381   //
 382   NOT_PRODUCT(int _no_safepoint_count;)         // If 0, thread allow a safepoint to happen
 383 
 384  private:
 385   // Used by SkipGCALot class.
 386   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 387 
 388   friend class GCLocker;
 389   friend class NoSafepointVerifier;
 390   friend class PauseNoSafepointVerifier;
 391 
 392   volatile void* _polling_page;                 // Thread local polling page
 393 
 394   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 395   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 396                                                 // the Java heap
 397   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 398 
 399   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 400 
 401   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 402 
 403   int   _vm_operation_started_count;            // VM_Operation support
 404   int   _vm_operation_completed_count;          // VM_Operation support
 405 
 406   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 407                                                 // is waiting to lock
 408   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 409 
 410   // ObjectMonitor on which this thread called Object.wait()
 411   ObjectMonitor* _current_waiting_monitor;
 412 
 413   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 414  public:
 415   ObjectMonitor* omFreeList;
 416   int omFreeCount;                              // length of omFreeList
 417   int omFreeProvision;                          // reload chunk size
 418   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 419   int omInUseCount;                             // length of omInUseList
 420 
 421 #ifdef ASSERT
 422  private:
 423   volatile uint64_t _visited_for_critical_count;
 424 
 425  public:
 426   void set_visited_for_critical_count(uint64_t safepoint_id) {
 427     assert(_visited_for_critical_count == 0, "Must be reset before set");
 428     assert((safepoint_id & 0x1) == 1, "Must be odd");
 429     _visited_for_critical_count = safepoint_id;
 430   }
 431   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 432     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 433     _visited_for_critical_count = 0;
 434   }
 435   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 436     return _visited_for_critical_count == safepoint_id;
 437   }
 438 #endif
 439 
 440  public:
 441   enum {
 442     is_definitely_current_thread = true
 443   };
 444 
 445   // Constructor
 446   Thread();
 447   virtual ~Thread() = 0;        // Thread is abstract.
 448 
 449   // Manage Thread::current()
 450   void initialize_thread_current();
 451   static void clear_thread_current(); // TLS cleanup needed before threads terminate
 452 
 453  protected:
 454   // To be implemented by children.
 455   virtual void run() = 0;
 456   virtual void pre_run() = 0;
 457   virtual void post_run() = 0;  // Note: Thread must not be deleted prior to calling this!
 458 
 459 #ifdef ASSERT
 460   enum RunState {
 461     PRE_CALL_RUN,
 462     CALL_RUN,
 463     PRE_RUN,
 464     RUN,
 465     POST_RUN
 466     // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
 467   };
 468   RunState _run_state;  // for lifecycle checks
 469 #endif
 470 
 471 
 472  public:
 473   // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
 474   void call_run();
 475 
 476   // Testers
 477   virtual bool is_VM_thread()       const            { return false; }
 478   virtual bool is_Java_thread()     const            { return false; }
 479   virtual bool is_Compiler_thread() const            { return false; }
 480   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 481   virtual bool is_hidden_from_external_view() const  { return false; }
 482   virtual bool is_jvmti_agent_thread() const         { return false; }
 483   // True iff the thread can perform GC operations at a safepoint.
 484   // Generally will be true only of VM thread and parallel GC WorkGang
 485   // threads.
 486   virtual bool is_GC_task_thread() const             { return false; }
 487   virtual bool is_Watcher_thread() const             { return false; }
 488   virtual bool is_ConcurrentGC_thread() const        { return false; }
 489   virtual bool is_Named_thread() const               { return false; }
 490   virtual bool is_Worker_thread() const              { return false; }
 491 
 492   // Can this thread make Java upcalls
 493   virtual bool can_call_java() const                 { return false; }
 494 
 495   // Is this a JavaThread that is on the VM's current ThreadsList?
 496   // If so it must participate in the safepoint protocol.
 497   virtual bool is_active_Java_thread() const         { return false; }
 498 
 499   // Casts
 500   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 501 
 502   virtual char* name() const { return (char*)"Unknown thread"; }
 503 
 504   // Returns the current thread (ASSERTS if NULL)
 505   static inline Thread* current();
 506   // Returns the current thread, or NULL if not attached
 507   static inline Thread* current_or_null();
 508   // Returns the current thread, or NULL if not attached, and is
 509   // safe for use from signal-handlers
 510   static inline Thread* current_or_null_safe();
 511 
 512   // Common thread operations
 513 #ifdef ASSERT
 514   static void check_for_dangling_thread_pointer(Thread *thread);
 515 #endif
 516   static void set_priority(Thread* thread, ThreadPriority priority);
 517   static ThreadPriority get_priority(const Thread* const thread);
 518   static void start(Thread* thread);
 519   static void interrupt(Thread* thr);
 520   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 521 
 522   void set_native_thread_name(const char *name) {
 523     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 524     os::set_native_thread_name(name);
 525   }
 526 
 527   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 528   Monitor* SR_lock() const                       { return _SR_lock; }
 529 
 530   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 531 
 532   inline void set_suspend_flag(SuspendFlags f);
 533   inline void clear_suspend_flag(SuspendFlags f);
 534 
 535   inline void set_has_async_exception();
 536   inline void clear_has_async_exception();
 537 
 538   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 539 
 540   inline void set_critical_native_unlock();
 541   inline void clear_critical_native_unlock();
 542 
 543   inline void set_trace_flag();
 544   inline void clear_trace_flag();
 545 
 546   // Support for Unhandled Oop detection
 547   // Add the field for both, fastdebug and debug, builds to keep
 548   // Thread's fields layout the same.
 549   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 550 #ifdef CHECK_UNHANDLED_OOPS
 551  private:
 552   UnhandledOops* _unhandled_oops;
 553 #elif defined(ASSERT)
 554  private:
 555   void* _unhandled_oops;
 556 #endif
 557 #ifdef CHECK_UNHANDLED_OOPS
 558  public:
 559   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 560   // Mark oop safe for gc.  It may be stack allocated but won't move.
 561   void allow_unhandled_oop(oop *op) {
 562     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 563   }
 564   // Clear oops at safepoint so crashes point to unhandled oop violator
 565   void clear_unhandled_oops() {
 566     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 567   }
 568 #endif // CHECK_UNHANDLED_OOPS
 569 
 570  public:
 571 #ifndef PRODUCT
 572   bool skip_gcalot()           { return _skip_gcalot; }
 573   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 574 #endif
 575 
 576   // Installs a pending exception to be inserted later
 577   static void send_async_exception(oop thread_oop, oop java_throwable);
 578 
 579   // Resource area
 580   ResourceArea* resource_area() const            { return _resource_area; }
 581   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 582 
 583   OSThread* osthread() const                     { return _osthread;   }
 584   void set_osthread(OSThread* thread)            { _osthread = thread; }
 585 
 586   // JNI handle support
 587   JNIHandleBlock* active_handles() const         { return _active_handles; }
 588   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 589   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 590   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 591 
 592   // Internal handle support
 593   HandleArea* handle_area() const                { return _handle_area; }
 594   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 595 
 596   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 597   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 598 
 599   // Thread-Local Allocation Buffer (TLAB) support
 600   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 601   void initialize_tlab() {
 602     if (UseTLAB) {
 603       tlab().initialize();
 604     }
 605   }
 606 
 607   jlong allocated_bytes()               { return _allocated_bytes; }
 608   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 609   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 610   inline jlong cooked_allocated_bytes();
 611 
 612   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 613 
 614   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 615 
 616   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 617 
 618   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 619 
 620   // VM operation support
 621   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 622   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 623   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 624 
 625   // For tracking the heavyweight monitor the thread is pending on.
 626   ObjectMonitor* current_pending_monitor() {
 627     return _current_pending_monitor;
 628   }
 629   void set_current_pending_monitor(ObjectMonitor* monitor) {
 630     _current_pending_monitor = monitor;
 631   }
 632   void set_current_pending_monitor_is_from_java(bool from_java) {
 633     _current_pending_monitor_is_from_java = from_java;
 634   }
 635   bool current_pending_monitor_is_from_java() {
 636     return _current_pending_monitor_is_from_java;
 637   }
 638 
 639   // For tracking the ObjectMonitor on which this thread called Object.wait()
 640   ObjectMonitor* current_waiting_monitor() {
 641     return _current_waiting_monitor;
 642   }
 643   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 644     _current_waiting_monitor = monitor;
 645   }
 646 
 647   // GC support
 648   // Apply "f->do_oop" to all root oops in "this".
 649   //   Used by JavaThread::oops_do.
 650   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 651   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 652 
 653   // Handles the parallel case for claim_threads_do.
 654  private:
 655   bool claim_par_threads_do(uintx claim_token);
 656  public:
 657   // Requires that "claim_token" is that of the current iteration.
 658   // If "is_par" is false, sets the token of "this" to
 659   // "claim_token", and returns "true".  If "is_par" is true,
 660   // uses an atomic instruction to set the current thread's token to
 661   // "claim_token", if it is not already.  Returns "true" iff the
 662   // calling thread does the update, this indicates that the calling thread
 663   // has claimed the thread in the current iteration.
 664   bool claim_threads_do(bool is_par, uintx claim_token) {
 665     if (!is_par) {
 666       _threads_do_token = claim_token;
 667       return true;
 668     } else {
 669       return claim_par_threads_do(claim_token);
 670     }
 671   }
 672 
 673   uintx threads_do_token() const { return _threads_do_token; }
 674 
 675   // jvmtiRedefineClasses support
 676   void metadata_handles_do(void f(Metadata*));
 677 
 678   // Used by fast lock support
 679   virtual bool is_lock_owned(address adr) const;
 680 
 681   // Check if address is in the stack of the thread (not just for locks).
 682   // Warning: the method can only be used on the running thread
 683   bool is_in_stack(address adr) const;
 684   // Check if address is in the usable part of the stack (excludes protected
 685   // guard pages)
 686   bool is_in_usable_stack(address adr) const;
 687 
 688   // Sets this thread as starting thread. Returns failure if thread
 689   // creation fails due to lack of memory, too many threads etc.
 690   bool set_as_starting_thread();
 691 
 692 protected:
 693   // OS data associated with the thread
 694   OSThread* _osthread;  // Platform-specific thread information
 695 
 696   // Thread local resource area for temporary allocation within the VM
 697   ResourceArea* _resource_area;
 698 
 699   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 700 
 701   // Thread local handle area for allocation of handles within the VM
 702   HandleArea* _handle_area;
 703   GrowableArray<Metadata*>* _metadata_handles;
 704 
 705   // Support for stack overflow handling, get_thread, etc.
 706   address          _stack_base;
 707   size_t           _stack_size;
 708   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 709   int              _lgrp_id;
 710 
 711   volatile void** polling_page_addr() { return &_polling_page; }
 712 
 713  public:
 714   // Stack overflow support
 715   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 716   void    set_stack_base(address base) { _stack_base = base; }
 717   size_t  stack_size() const           { return _stack_size; }
 718   void    set_stack_size(size_t size)  { _stack_size = size; }
 719   address stack_end()  const           { return stack_base() - stack_size(); }
 720   void    record_stack_base_and_size();
 721   void    register_thread_stack_with_NMT() NOT_NMT_RETURN;
 722 
 723   bool    on_local_stack(address adr) const {
 724     // QQQ this has knowledge of direction, ought to be a stack method
 725     return (_stack_base >= adr && adr >= stack_end());
 726   }
 727 
 728   uintptr_t self_raw_id()                    { return _self_raw_id; }
 729   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 730 
 731   int     lgrp_id() const        { return _lgrp_id; }
 732   void    set_lgrp_id(int value) { _lgrp_id = value; }
 733 
 734   // Printing
 735   void print_on(outputStream* st, bool print_extended_info) const;
 736   virtual void print_on(outputStream* st) const { print_on(st, false); }
 737   void print() const;
 738   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 739   void print_value_on(outputStream* st) const;
 740 
 741   // Debug-only code
 742 #ifdef ASSERT
 743  private:
 744   // Deadlock detection support for Mutex locks. List of locks own by thread.
 745   Monitor* _owned_locks;
 746   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 747   // thus the friendship
 748   friend class Mutex;
 749   friend class Monitor;
 750 
 751  public:
 752   void print_owned_locks_on(outputStream* st) const;
 753   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 754   Monitor* owned_locks() const                   { return _owned_locks;          }
 755   bool owns_locks() const                        { return owned_locks() != NULL; }
 756   bool owns_locks_but_compiled_lock() const;
 757 
 758   // Deadlock detection
 759   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 760   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 761 #endif // ASSERT
 762 
 763   // These functions check conditions on a JavaThread before possibly going to a safepoint,
 764   // including NoSafepointVerifier.
 765   void check_for_valid_safepoint_state(bool potential_vm_operation) NOT_DEBUG_RETURN;
 766   void check_possible_safepoint() NOT_DEBUG_RETURN;
 767 
 768  private:
 769   volatile int _jvmti_env_iteration_count;
 770 
 771  public:
 772   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 773   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 774   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 775 
 776   // Code generation
 777   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 778   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 779   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 780 
 781   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 782   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 783 
 784   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 785 
 786   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 787   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 788   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 789   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 790 
 791   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 792 
 793   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 794 
 795  public:
 796   volatile intptr_t _Stalled;
 797   volatile int _TypeTag;
 798   ParkEvent * _ParkEvent;                     // for synchronized()
 799   ParkEvent * _SleepEvent;                    // for Thread.sleep
 800   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 801   int NativeSyncRecursion;                    // diagnostic
 802 
 803   volatile int _OnTrap;                       // Resume-at IP delta
 804   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 805   jint _hashStateX;                           // thread-specific hashCode generator state
 806   jint _hashStateY;
 807   jint _hashStateZ;
 808 
 809   // Low-level leaf-lock primitives used to implement synchronization
 810   // and native monitor-mutex infrastructure.
 811   // Not for general synchronization use.
 812   static void SpinAcquire(volatile int * Lock, const char * Name);
 813   static void SpinRelease(volatile int * Lock);
 814   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 815   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 816   static void muxRelease(volatile intptr_t * Lock);
 817 };
 818 
 819 // Inline implementation of Thread::current()
 820 inline Thread* Thread::current() {
 821   Thread* current = current_or_null();
 822   assert(current != NULL, "Thread::current() called on detached thread");
 823   return current;
 824 }
 825 
 826 inline Thread* Thread::current_or_null() {
 827 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 828   return _thr_current;
 829 #else
 830   if (ThreadLocalStorage::is_initialized()) {
 831     return ThreadLocalStorage::thread();
 832   }
 833   return NULL;
 834 #endif
 835 }
 836 
 837 inline Thread* Thread::current_or_null_safe() {
 838   if (ThreadLocalStorage::is_initialized()) {
 839     return ThreadLocalStorage::thread();
 840   }
 841   return NULL;
 842 }
 843 
 844 class NonJavaThread: public Thread {
 845   friend class VMStructs;
 846 
 847   NonJavaThread* volatile _next;
 848 
 849   class List;
 850   static List _the_list;
 851 
 852   void add_to_the_list();
 853   void remove_from_the_list();
 854 
 855  protected:
 856   virtual void pre_run();
 857   virtual void post_run();
 858 
 859  public:
 860   NonJavaThread();
 861   ~NonJavaThread();
 862 
 863   class Iterator;
 864 };
 865 
 866 // Provides iteration over the list of NonJavaThreads.
 867 // List addition occurs in pre_run(), and removal occurs in post_run(),
 868 // so that only live fully-initialized threads can be found in the list.
 869 // Threads created after an iterator is constructed will not be visited
 870 // by the iterator. The scope of an iterator is a critical section; there
 871 // must be no safepoint checks in that scope.
 872 class NonJavaThread::Iterator : public StackObj {
 873   uint _protect_enter;
 874   NonJavaThread* _current;
 875 
 876   // Noncopyable.
 877   Iterator(const Iterator&);
 878   Iterator& operator=(const Iterator&);
 879 
 880 public:
 881   Iterator();
 882   ~Iterator();
 883 
 884   bool end() const { return _current == NULL; }
 885   NonJavaThread* current() const { return _current; }
 886   void step();
 887 };
 888 
 889 // Name support for threads.  non-JavaThread subclasses with multiple
 890 // uniquely named instances should derive from this.
 891 class NamedThread: public NonJavaThread {
 892   friend class VMStructs;
 893   enum {
 894     max_name_len = 64
 895   };
 896  private:
 897   char* _name;
 898   // log JavaThread being processed by oops_do
 899   JavaThread* _processed_thread;
 900   uint _gc_id; // The current GC id when a thread takes part in GC
 901 
 902  public:
 903   NamedThread();
 904   ~NamedThread();
 905   // May only be called once per thread.
 906   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 907   virtual bool is_Named_thread() const { return true; }
 908   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 909   JavaThread *processed_thread() { return _processed_thread; }
 910   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 911   virtual void print_on(outputStream* st) const;
 912 
 913   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 914   uint gc_id() { return _gc_id; }
 915 };
 916 
 917 // Worker threads are named and have an id of an assigned work.
 918 class WorkerThread: public NamedThread {
 919  private:
 920   uint _id;
 921  public:
 922   WorkerThread() : _id(0)               { }
 923   virtual bool is_Worker_thread() const { return true; }
 924 
 925   virtual WorkerThread* as_Worker_thread() const {
 926     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 927     return (WorkerThread*) this;
 928   }
 929 
 930   void set_id(uint work_id)             { _id = work_id; }
 931   uint id() const                       { return _id; }
 932 };
 933 
 934 // A single WatcherThread is used for simulating timer interrupts.
 935 class WatcherThread: public NonJavaThread {
 936   friend class VMStructs;
 937  protected:
 938   virtual void run();
 939 
 940  private:
 941   static WatcherThread* _watcher_thread;
 942 
 943   static bool _startable;
 944   // volatile due to at least one lock-free read
 945   volatile static bool _should_terminate;
 946  public:
 947   enum SomeConstants {
 948     delay_interval = 10                          // interrupt delay in milliseconds
 949   };
 950 
 951   // Constructor
 952   WatcherThread();
 953 
 954   // No destruction allowed
 955   ~WatcherThread() {
 956     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 957   }
 958 
 959   // Tester
 960   bool is_Watcher_thread() const                 { return true; }
 961 
 962   // Printing
 963   char* name() const { return (char*)"VM Periodic Task Thread"; }
 964   void print_on(outputStream* st) const;
 965   void unpark();
 966 
 967   // Returns the single instance of WatcherThread
 968   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 969 
 970   // Create and start the single instance of WatcherThread, or stop it on shutdown
 971   static void start();
 972   static void stop();
 973   // Only allow start once the VM is sufficiently initialized
 974   // Otherwise the first task to enroll will trigger the start
 975   static void make_startable();
 976  private:
 977   int sleep() const;
 978 };
 979 
 980 
 981 class CompilerThread;
 982 
 983 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 984 
 985 class JavaThread: public Thread {
 986   friend class VMStructs;
 987   friend class JVMCIVMStructs;
 988   friend class WhiteBox;
 989  private:
 990   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 991   oop            _threadObj;                     // The Java level thread object
 992 
 993 #ifdef ASSERT
 994  private:
 995   int _java_call_counter;
 996 
 997  public:
 998   int  java_call_counter()                       { return _java_call_counter; }
 999   void inc_java_call_counter()                   { _java_call_counter++; }
1000   void dec_java_call_counter() {
1001     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
1002     _java_call_counter--;
1003   }
1004  private:  // restore original namespace restriction
1005 #endif  // ifdef ASSERT
1006 
1007 #ifndef PRODUCT
1008  public:
1009   enum {
1010     jump_ring_buffer_size = 16
1011   };
1012  private:  // restore original namespace restriction
1013 #endif
1014 
1015   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
1016 
1017   ThreadFunction _entry_point;
1018 
1019   JNIEnv        _jni_environment;
1020 
1021   // Deopt support
1022   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
1023 
1024   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
1025                                                  // transition out of native
1026   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
1027   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
1028   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
1029   // Because deoptimization is lazy we must save jvmti requests to set locals
1030   // in compiled frames until we deoptimize and we have an interpreter frame.
1031   // This holds the pointer to array (yeah like there might be more than one) of
1032   // description of compiled vframes that have locals that need to be updated.
1033   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
1034 
1035   // Handshake value for fixing 6243940. We need a place for the i2c
1036   // adapter to store the callee Method*. This value is NEVER live
1037   // across a gc point so it does NOT have to be gc'd
1038   // The handshake is open ended since we can't be certain that it will
1039   // be NULLed. This is because we rarely ever see the race and end up
1040   // in handle_wrong_method which is the backend of the handshake. See
1041   // code in i2c adapters and handle_wrong_method.
1042 
1043   Method*       _callee_target;
1044 
1045   // Used to pass back results to the interpreter or generated code running Java code.
1046   oop           _vm_result;    // oop result is GC-preserved
1047   Metadata*     _vm_result_2;  // non-oop result
1048 
1049   // See ReduceInitialCardMarks: this holds the precise space interval of
1050   // the most recent slow path allocation for which compiled code has
1051   // elided card-marks for performance along the fast-path.
1052   MemRegion     _deferred_card_mark;
1053 
1054   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
1055                                                  // allocated during deoptimization
1056                                                  // and by JNI_MonitorEnter/Exit
1057 
1058   // Async. requests support
1059   enum AsyncRequests {
1060     _no_async_condition = 0,
1061     _async_exception,
1062     _async_unsafe_access_error
1063   };
1064   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1065   oop           _pending_async_exception;
1066 
1067   // Safepoint support
1068  public:                                         // Expose _thread_state for SafeFetchInt()
1069   volatile JavaThreadState _thread_state;
1070  private:
1071   ThreadSafepointState* _safepoint_state;        // Holds information about a thread during a safepoint
1072   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
1073 
1074   // JavaThread termination support
1075   enum TerminatedTypes {
1076     _not_terminated = 0xDEAD - 2,
1077     _thread_exiting,                             // JavaThread::exit() has been called for this thread
1078     _thread_terminated,                          // JavaThread is removed from thread list
1079     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
1080                                                  // only VM_Exit can set _vm_exited
1081   };
1082 
1083   // In general a JavaThread's _terminated field transitions as follows:
1084   //
1085   //   _not_terminated => _thread_exiting => _thread_terminated
1086   //
1087   // _vm_exited is a special value to cover the case of a JavaThread
1088   // executing native code after the VM itself is terminated.
1089   volatile TerminatedTypes _terminated;
1090   // suspend/resume support
1091   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1092   jint                  _in_deopt_handler;       // count of deoptimization
1093                                                  // handlers thread is in
1094   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1095   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1096                                                          // never locked) when throwing an exception. Used by interpreter only.
1097 
1098   // JNI attach states:
1099   enum JNIAttachStates {
1100     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1101     _attaching_via_jni,          // thread is attaching via JNI
1102     _attached_via_jni            // thread has attached via JNI
1103   };
1104 
1105   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1106   // A native thread that is attaching via JNI starts with a value
1107   // of _attaching_via_jni and transitions to _attached_via_jni.
1108   volatile JNIAttachStates _jni_attach_state;
1109 
1110  public:
1111   // State of the stack guard pages for this thread.
1112   enum StackGuardState {
1113     stack_guard_unused,         // not needed
1114     stack_guard_reserved_disabled,
1115     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1116     stack_guard_enabled         // enabled
1117   };
1118 
1119  private:
1120 
1121 #if INCLUDE_JVMCI
1122   // The _pending_* fields below are used to communicate extra information
1123   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1124 
1125   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1126   int       _pending_deoptimization;
1127 
1128   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1129   // before the monitor has been acquired.
1130   bool      _pending_monitorenter;
1131 
1132   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1133   bool      _pending_transfer_to_interpreter;
1134 
1135   // True if in a runtime call from compiled code that will deoptimize
1136   // and re-execute a failed heap allocation in the interpreter.
1137   bool      _in_retryable_allocation;
1138 
1139   // An id of a speculation that JVMCI compiled code can use to further describe and
1140   // uniquely identify the  speculative optimization guarded by the uncommon trap
1141   jlong     _pending_failed_speculation;
1142 
1143   // These fields are mutually exclusive in terms of live ranges.
1144   union {
1145     // Communicates the pc at which the most recent implicit exception occurred
1146     // from the signal handler to a deoptimization stub.
1147     address   _implicit_exception_pc;
1148 
1149     // Communicates an alternative call target to an i2c stub from a JavaCall .
1150     address   _alternate_call_target;
1151   } _jvmci;
1152 
1153   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1154   jlong*    _jvmci_counters;
1155 
1156  public:
1157   static jlong* _jvmci_old_thread_counters;
1158   static void collect_counters(jlong* array, int length);
1159 
1160   bool resize_counters(int current_size, int new_size);
1161 
1162   static bool resize_all_jvmci_counters(int new_size);
1163 
1164  private:
1165 #endif // INCLUDE_JVMCI
1166 
1167   StackGuardState  _stack_guard_state;
1168 
1169   // Precompute the limit of the stack as used in stack overflow checks.
1170   // We load it from here to simplify the stack overflow check in assembly.
1171   address          _stack_overflow_limit;
1172   address          _reserved_stack_activation;
1173 
1174   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1175   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1176   // code)
1177   volatile oop     _exception_oop;               // Exception thrown in compiled code
1178   volatile address _exception_pc;                // PC where exception happened
1179   volatile address _exception_handler_pc;        // PC for handler of exception
1180   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1181 
1182  private:
1183   // support for JNI critical regions
1184   jint    _jni_active_critical;                  // count of entries into JNI critical region
1185 
1186   // Checked JNI: function name requires exception check
1187   char* _pending_jni_exception_check_fn;
1188 
1189   // For deadlock detection.
1190   int _depth_first_number;
1191 
1192   // JVMTI PopFrame support
1193   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1194   int _popframe_condition;
1195 
1196   // If reallocation of scalar replaced objects fails, we throw OOM
1197   // and during exception propagation, pop the top
1198   // _frames_to_pop_failed_realloc frames, the ones that reference
1199   // failed reallocations.
1200   int _frames_to_pop_failed_realloc;
1201 
1202 #ifndef PRODUCT
1203   int _jmp_ring_index;
1204   struct {
1205     // We use intptr_t instead of address so debugger doesn't try and display strings
1206     intptr_t _target;
1207     intptr_t _instruction;
1208     const char*  _file;
1209     int _line;
1210   }   _jmp_ring[jump_ring_buffer_size];
1211 #endif // PRODUCT
1212 
1213   friend class VMThread;
1214   friend class ThreadWaitTransition;
1215   friend class VM_Exit;
1216 
1217   void initialize();                             // Initialized the instance variables
1218 
1219  public:
1220   // Constructor
1221   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1222   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1223   ~JavaThread();
1224 
1225 #ifdef ASSERT
1226   // verify this JavaThread hasn't be published in the Threads::list yet
1227   void verify_not_published();
1228 #endif // ASSERT
1229 
1230   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1231   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1232     _jni_environment.functions = functionTable;
1233   }
1234   struct JNINativeInterface_* get_jni_functions() {
1235     return (struct JNINativeInterface_ *)_jni_environment.functions;
1236   }
1237 
1238   // This function is called at thread creation to allow
1239   // platform specific thread variables to be initialized.
1240   void cache_global_variables();
1241 
1242   // Executes Shutdown.shutdown()
1243   void invoke_shutdown_hooks();
1244 
1245   // Cleanup on thread exit
1246   enum ExitType {
1247     normal_exit,
1248     jni_detach
1249   };
1250   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1251 
1252   void cleanup_failed_attach_current_thread(bool is_daemon);
1253 
1254   // Testers
1255   virtual bool is_Java_thread() const            { return true;  }
1256   virtual bool can_call_java() const             { return true; }
1257 
1258   virtual bool is_active_Java_thread() const {
1259     return on_thread_list() && !is_terminated();
1260   }
1261 
1262   // Thread oop. threadObj() can be NULL for initial JavaThread
1263   // (or for threads attached via JNI)
1264   oop threadObj() const                          { return _threadObj; }
1265   void set_threadObj(oop p)                      { _threadObj = p; }
1266 
1267   ThreadPriority java_priority() const;          // Read from threadObj()
1268 
1269   // Prepare thread and add to priority queue.  If a priority is
1270   // not specified, use the priority of the thread object. Threads_lock
1271   // must be held while this function is called.
1272   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1273 
1274   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1275   address saved_exception_pc()                   { return _saved_exception_pc; }
1276 
1277 
1278   ThreadFunction entry_point() const             { return _entry_point; }
1279 
1280   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1281   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1282 
1283   // Last frame anchor routines
1284 
1285   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1286 
1287   // last_Java_sp
1288   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1289   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1290 
1291   // last_Java_pc
1292 
1293   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1294 
1295   // Safepoint support
1296   inline JavaThreadState thread_state() const;
1297   inline void set_thread_state(JavaThreadState s);
1298   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
1299   inline ThreadSafepointState* safepoint_state() const;
1300   inline void set_safepoint_state(ThreadSafepointState* state);
1301   inline bool is_at_poll_safepoint();
1302 
1303   // JavaThread termination and lifecycle support:
1304   void smr_delete();
1305   bool on_thread_list() const { return _on_thread_list; }
1306   void set_on_thread_list() { _on_thread_list = true; }
1307 
1308   // thread has called JavaThread::exit() or is terminated
1309   bool is_exiting() const;
1310   // thread is terminated (no longer on the threads list); we compare
1311   // against the two non-terminated values so that a freed JavaThread
1312   // will also be considered terminated.
1313   bool check_is_terminated(TerminatedTypes l_terminated) const {
1314     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1315   }
1316   bool is_terminated() const;
1317   void set_terminated(TerminatedTypes t);
1318   // special for Threads::remove() which is static:
1319   void set_terminated_value();
1320   void block_if_vm_exited();
1321 
1322   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1323   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1324 
1325   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1326   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1327 
1328   inline void set_polling_page_release(void* poll_value);
1329   inline void set_polling_page(void* poll_value);
1330   inline volatile void* get_polling_page();
1331 
1332  private:
1333   // Support for thread handshake operations
1334   HandshakeState _handshake;
1335  public:
1336   void set_handshake_operation(HandshakeOperation* op) {
1337     _handshake.set_operation(this, op);
1338   }
1339 
1340   bool has_handshake() const {
1341     return _handshake.has_operation();
1342   }
1343 
1344   void handshake_process_by_self() {
1345     _handshake.process_by_self(this);
1346   }
1347 
1348   void handshake_process_by_vmthread() {
1349     _handshake.process_by_vmthread(this);
1350   }
1351 
1352   // Suspend/resume support for JavaThread
1353  private:
1354   inline void set_ext_suspended();
1355   inline void clear_ext_suspended();
1356 
1357  public:
1358   void java_suspend(); // higher-level suspension logic called by the public APIs
1359   void java_resume();  // higher-level resume logic called by the public APIs
1360   int  java_suspend_self(); // low-level self-suspension mechanics
1361 
1362  private:
1363   // mid-level wrapper around java_suspend_self to set up correct state and
1364   // check for a pending safepoint at the end
1365   void java_suspend_self_with_safepoint_check();
1366 
1367  public:
1368   void check_and_wait_while_suspended() {
1369     assert(JavaThread::current() == this, "sanity check");
1370 
1371     bool do_self_suspend;
1372     do {
1373       // were we externally suspended while we were waiting?
1374       do_self_suspend = handle_special_suspend_equivalent_condition();
1375       if (do_self_suspend) {
1376         // don't surprise the thread that suspended us by returning
1377         java_suspend_self();
1378         set_suspend_equivalent();
1379       }
1380     } while (do_self_suspend);
1381   }
1382   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1383   // Check for async exception in addition to safepoint and suspend request.
1384   static void check_special_condition_for_native_trans(JavaThread *thread);
1385 
1386   // Same as check_special_condition_for_native_trans but finishes the
1387   // transition into thread_in_Java mode so that it can potentially
1388   // block.
1389   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1390 
1391   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1392   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1393     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1394     // Warning: is_ext_suspend_completed() may temporarily drop the
1395     // SR_lock to allow the thread to reach a stable thread state if
1396     // it is currently in a transient thread state.
1397     return is_ext_suspend_completed(false /* !called_by_wait */,
1398                                     SuspendRetryDelay, bits);
1399   }
1400 
1401   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1402   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1403   // passed as the count and delay parameters. Experiments with specific
1404   // calls to wait_for_ext_suspend_completion() can be done by passing
1405   // other values in the code. Experiments with all calls can be done
1406   // via the appropriate -XX options.
1407   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1408 
1409   // test for suspend - most (all?) of these should go away
1410   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1411 
1412   inline void set_external_suspend();
1413   inline void clear_external_suspend();
1414 
1415   bool is_external_suspend() const {
1416     return (_suspend_flags & _external_suspend) != 0;
1417   }
1418   // Whenever a thread transitions from native to vm/java it must suspend
1419   // if external|deopt suspend is present.
1420   bool is_suspend_after_native() const {
1421     return (_suspend_flags & (_external_suspend JFR_ONLY(| _trace_flag))) != 0;
1422   }
1423 
1424   // external suspend request is completed
1425   bool is_ext_suspended() const {
1426     return (_suspend_flags & _ext_suspended) != 0;
1427   }
1428 
1429   bool is_external_suspend_with_lock() const {
1430     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1431     return is_external_suspend();
1432   }
1433 
1434   // Special method to handle a pending external suspend request
1435   // when a suspend equivalent condition lifts.
1436   bool handle_special_suspend_equivalent_condition() {
1437     assert(is_suspend_equivalent(),
1438            "should only be called in a suspend equivalence condition");
1439     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1440     bool ret = is_external_suspend();
1441     if (!ret) {
1442       // not about to self-suspend so clear suspend equivalence
1443       clear_suspend_equivalent();
1444     }
1445     // implied else:
1446     // We have a pending external suspend request so we leave the
1447     // suspend_equivalent flag set until java_suspend_self() sets
1448     // the ext_suspended flag and clears the suspend_equivalent
1449     // flag. This insures that wait_for_ext_suspend_completion()
1450     // will return consistent values.
1451     return ret;
1452   }
1453 
1454   // utility methods to see if we are doing some kind of suspension
1455   bool is_being_ext_suspended() const            {
1456     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1457     return is_ext_suspended() || is_external_suspend();
1458   }
1459 
1460   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1461 
1462   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1463   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1464 
1465   // Thread.stop support
1466   void send_thread_stop(oop throwable);
1467   AsyncRequests clear_special_runtime_exit_condition() {
1468     AsyncRequests x = _special_runtime_exit_condition;
1469     _special_runtime_exit_condition = _no_async_condition;
1470     return x;
1471   }
1472 
1473   // Are any async conditions present?
1474   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1475 
1476   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1477 
1478   // these next two are also used for self-suspension and async exception support
1479   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1480 
1481   // Return true if JavaThread has an asynchronous condition or
1482   // if external suspension is requested.
1483   bool has_special_runtime_exit_condition() {
1484     // Because we don't use is_external_suspend_with_lock
1485     // it is possible that we won't see an asynchronous external suspend
1486     // request that has just gotten started, i.e., SR_lock grabbed but
1487     // _external_suspend field change either not made yet or not visible
1488     // yet. However, this is okay because the request is asynchronous and
1489     // we will see the new flag value the next time through. It's also
1490     // possible that the external suspend request is dropped after
1491     // we have checked is_external_suspend(), we will recheck its value
1492     // under SR_lock in java_suspend_self().
1493     return (_special_runtime_exit_condition != _no_async_condition) ||
1494             is_external_suspend() || is_trace_suspend();
1495   }
1496 
1497   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1498 
1499   inline void set_pending_async_exception(oop e);
1500 
1501   // Fast-locking support
1502   bool is_lock_owned(address adr) const;
1503 
1504   // Accessors for vframe array top
1505   // The linked list of vframe arrays are sorted on sp. This means when we
1506   // unpack the head must contain the vframe array to unpack.
1507   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1508   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1509 
1510   // Side structure for deferring update of java frame locals until deopt occurs
1511   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1512   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1513 
1514   // These only really exist to make debugging deopt problems simpler
1515 
1516   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1517   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1518 
1519   // The special resourceMark used during deoptimization
1520 
1521   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1522   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1523 
1524   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1525   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1526   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1527 
1528   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1529   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1530 
1531   Method*    callee_target() const               { return _callee_target; }
1532   void set_callee_target  (Method* x)          { _callee_target   = x; }
1533 
1534   // Oop results of vm runtime calls
1535   oop  vm_result() const                         { return _vm_result; }
1536   void set_vm_result  (oop x)                    { _vm_result   = x; }
1537 
1538   Metadata*    vm_result_2() const               { return _vm_result_2; }
1539   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1540 
1541   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1542   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1543 
1544 #if INCLUDE_JVMCI
1545   int  pending_deoptimization() const             { return _pending_deoptimization; }
1546   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
1547   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1548   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1549   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1550   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
1551   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1552   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1553   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1554 
1555   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
1556   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
1557 #endif // INCLUDE_JVMCI
1558 
1559   // Exception handling for compiled methods
1560   oop      exception_oop() const                 { return _exception_oop; }
1561   address  exception_pc() const                  { return _exception_pc; }
1562   address  exception_handler_pc() const          { return _exception_handler_pc; }
1563   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1564 
1565   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1566   void set_exception_pc(address a)               { _exception_pc = a; }
1567   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1568   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1569 
1570   void clear_exception_oop_and_pc() {
1571     set_exception_oop(NULL);
1572     set_exception_pc(NULL);
1573   }
1574 
1575   // Stack overflow support
1576   //
1577   //  (small addresses)
1578   //
1579   //  --  <-- stack_end()                   ---
1580   //  |                                      |
1581   //  |  red pages                           |
1582   //  |                                      |
1583   //  --  <-- stack_red_zone_base()          |
1584   //  |                                      |
1585   //  |                                     guard
1586   //  |  yellow pages                       zone
1587   //  |                                      |
1588   //  |                                      |
1589   //  --  <-- stack_yellow_zone_base()       |
1590   //  |                                      |
1591   //  |                                      |
1592   //  |  reserved pages                      |
1593   //  |                                      |
1594   //  --  <-- stack_reserved_zone_base()    ---      ---
1595   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1596   //                                                  |   zone
1597   //                                                 \|/  size
1598   //  some untouched memory                          ---
1599   //
1600   //
1601   //  --
1602   //  |
1603   //  |  shadow zone
1604   //  |
1605   //  --
1606   //  x    frame n
1607   //  --
1608   //  x    frame n-1
1609   //  x
1610   //  --
1611   //  ...
1612   //
1613   //  --
1614   //  x    frame 0
1615   //  --  <-- stack_base()
1616   //
1617   //  (large addresses)
1618   //
1619 
1620  private:
1621   // These values are derived from flags StackRedPages, StackYellowPages,
1622   // StackReservedPages and StackShadowPages. The zone size is determined
1623   // ergonomically if page_size > 4K.
1624   static size_t _stack_red_zone_size;
1625   static size_t _stack_yellow_zone_size;
1626   static size_t _stack_reserved_zone_size;
1627   static size_t _stack_shadow_zone_size;
1628  public:
1629   inline size_t stack_available(address cur_sp);
1630 
1631   static size_t stack_red_zone_size() {
1632     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1633     return _stack_red_zone_size;
1634   }
1635   static void set_stack_red_zone_size(size_t s) {
1636     assert(is_aligned(s, os::vm_page_size()),
1637            "We can not protect if the red zone size is not page aligned.");
1638     assert(_stack_red_zone_size == 0, "This should be called only once.");
1639     _stack_red_zone_size = s;
1640   }
1641   address stack_red_zone_base() {
1642     return (address)(stack_end() + stack_red_zone_size());
1643   }
1644   bool in_stack_red_zone(address a) {
1645     return a <= stack_red_zone_base() && a >= stack_end();
1646   }
1647 
1648   static size_t stack_yellow_zone_size() {
1649     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1650     return _stack_yellow_zone_size;
1651   }
1652   static void set_stack_yellow_zone_size(size_t s) {
1653     assert(is_aligned(s, os::vm_page_size()),
1654            "We can not protect if the yellow zone size is not page aligned.");
1655     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1656     _stack_yellow_zone_size = s;
1657   }
1658 
1659   static size_t stack_reserved_zone_size() {
1660     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1661     return _stack_reserved_zone_size;
1662   }
1663   static void set_stack_reserved_zone_size(size_t s) {
1664     assert(is_aligned(s, os::vm_page_size()),
1665            "We can not protect if the reserved zone size is not page aligned.");
1666     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1667     _stack_reserved_zone_size = s;
1668   }
1669   address stack_reserved_zone_base() {
1670     return (address)(stack_end() +
1671                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1672   }
1673   bool in_stack_reserved_zone(address a) {
1674     return (a <= stack_reserved_zone_base()) &&
1675            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1676   }
1677 
1678   static size_t stack_yellow_reserved_zone_size() {
1679     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1680   }
1681   bool in_stack_yellow_reserved_zone(address a) {
1682     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1683   }
1684 
1685   // Size of red + yellow + reserved zones.
1686   static size_t stack_guard_zone_size() {
1687     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1688   }
1689 
1690   static size_t stack_shadow_zone_size() {
1691     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1692     return _stack_shadow_zone_size;
1693   }
1694   static void set_stack_shadow_zone_size(size_t s) {
1695     // The shadow area is not allocated or protected, so
1696     // it needs not be page aligned.
1697     // But the stack bang currently assumes that it is a
1698     // multiple of page size. This guarantees that the bang
1699     // loop touches all pages in the shadow zone.
1700     // This can be guaranteed differently, as well.  E.g., if
1701     // the page size is a multiple of 4K, banging in 4K steps
1702     // suffices to touch all pages. (Some pages are banged
1703     // several times, though.)
1704     assert(is_aligned(s, os::vm_page_size()),
1705            "Stack bang assumes multiple of page size.");
1706     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1707     _stack_shadow_zone_size = s;
1708   }
1709 
1710   void create_stack_guard_pages();
1711   void remove_stack_guard_pages();
1712 
1713   void enable_stack_reserved_zone();
1714   void disable_stack_reserved_zone();
1715   void enable_stack_yellow_reserved_zone();
1716   void disable_stack_yellow_reserved_zone();
1717   void enable_stack_red_zone();
1718   void disable_stack_red_zone();
1719 
1720   inline bool stack_guard_zone_unused();
1721   inline bool stack_yellow_reserved_zone_disabled();
1722   inline bool stack_reserved_zone_disabled();
1723   inline bool stack_guards_enabled();
1724 
1725   address reserved_stack_activation() const { return _reserved_stack_activation; }
1726   void set_reserved_stack_activation(address addr) {
1727     assert(_reserved_stack_activation == stack_base()
1728             || _reserved_stack_activation == NULL
1729             || addr == stack_base(), "Must not be set twice");
1730     _reserved_stack_activation = addr;
1731   }
1732 
1733   // Attempt to reguard the stack after a stack overflow may have occurred.
1734   // Returns true if (a) guard pages are not needed on this thread, (b) the
1735   // pages are already guarded, or (c) the pages were successfully reguarded.
1736   // Returns false if there is not enough stack space to reguard the pages, in
1737   // which case the caller should unwind a frame and try again.  The argument
1738   // should be the caller's (approximate) sp.
1739   bool reguard_stack(address cur_sp);
1740   // Similar to above but see if current stackpoint is out of the guard area
1741   // and reguard if possible.
1742   bool reguard_stack(void);
1743 
1744   address stack_overflow_limit() { return _stack_overflow_limit; }
1745   void set_stack_overflow_limit() {
1746     _stack_overflow_limit =
1747       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1748   }
1749 
1750   // Misc. accessors/mutators
1751   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1752   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1753   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1754 
1755 #ifndef PRODUCT
1756   void record_jump(address target, address instr, const char* file, int line);
1757 #endif // PRODUCT
1758 
1759   // For assembly stub generation
1760   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1761 #ifndef PRODUCT
1762   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1763   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1764 #endif // PRODUCT
1765   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1766   static ByteSize pending_jni_exception_check_fn_offset() {
1767     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1768   }
1769   static ByteSize last_Java_sp_offset() {
1770     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1771   }
1772   static ByteSize last_Java_pc_offset() {
1773     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1774   }
1775   static ByteSize frame_anchor_offset() {
1776     return byte_offset_of(JavaThread, _anchor);
1777   }
1778   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1779   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1780   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1781   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1782   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1783   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1784 #if INCLUDE_JVMCI
1785   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1786   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1787   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1788   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1789   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1790   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1791 #endif // INCLUDE_JVMCI
1792   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1793   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1794   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1795   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1796   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1797   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1798   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1799   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1800 
1801   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1802   static ByteSize should_post_on_exceptions_flag_offset() {
1803     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1804   }
1805   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
1806 
1807   // Returns the jni environment for this thread
1808   JNIEnv* jni_environment()                      { return &_jni_environment; }
1809 
1810   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1811     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1812     // Only return NULL if thread is off the thread list; starting to
1813     // exit should not return NULL.
1814     if (thread_from_jni_env->is_terminated()) {
1815       thread_from_jni_env->block_if_vm_exited();
1816       return NULL;
1817     } else {
1818       return thread_from_jni_env;
1819     }
1820   }
1821 
1822   // JNI critical regions. These can nest.
1823   bool in_critical()    { return _jni_active_critical > 0; }
1824   bool in_last_critical()  { return _jni_active_critical == 1; }
1825   inline void enter_critical();
1826   void exit_critical() {
1827     assert(Thread::current() == this, "this must be current thread");
1828     _jni_active_critical--;
1829     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1830   }
1831 
1832   // Checked JNI: is the programmer required to check for exceptions, if so specify
1833   // which function name. Returning to a Java frame should implicitly clear the
1834   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1835   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1836   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1837   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1838   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1839   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1840   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1841 
1842   // For deadlock detection
1843   int depth_first_number() { return _depth_first_number; }
1844   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1845 
1846  private:
1847   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1848 
1849  public:
1850   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1851   void add_monitor_chunk(MonitorChunk* chunk);
1852   void remove_monitor_chunk(MonitorChunk* chunk);
1853   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1854   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1855   void dec_in_deopt_handler() {
1856     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1857     if (_in_deopt_handler > 0) { // robustness
1858       _in_deopt_handler--;
1859     }
1860   }
1861 
1862  private:
1863   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1864 
1865  public:
1866 
1867   // Frame iteration; calls the function f for all frames on the stack
1868   void frames_do(void f(frame*, const RegisterMap*));
1869 
1870   // Memory operations
1871   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1872 
1873   // Sweeper operations
1874   virtual void nmethods_do(CodeBlobClosure* cf);
1875 
1876   // RedefineClasses Support
1877   void metadata_do(MetadataClosure* f);
1878 
1879   // Debug method asserting thread states are correct during a handshake operation.
1880   DEBUG_ONLY(void verify_states_for_handshake();)
1881 
1882   // Misc. operations
1883   char* name() const { return (char*)get_thread_name(); }
1884   void print_on(outputStream* st, bool print_extended_info) const;
1885   void print_on(outputStream* st) const { print_on(st, false); }
1886   void print() const;
1887   void print_value();
1888   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1889   void print_thread_state() const                      PRODUCT_RETURN;
1890   void print_on_error(outputStream* st, char* buf, int buflen) const;
1891   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1892   void verify();
1893   const char* get_thread_name() const;
1894  protected:
1895   // factor out low-level mechanics for use in both normal and error cases
1896   virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1897  public:
1898   const char* get_threadgroup_name() const;
1899   const char* get_parent_name() const;
1900 
1901   // Accessing frames
1902   frame last_frame() {
1903     _anchor.make_walkable(this);
1904     return pd_last_frame();
1905   }
1906   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1907 
1908   // Returns method at 'depth' java or native frames down the stack
1909   // Used for security checks
1910   Klass* security_get_caller_class(int depth);
1911 
1912   // Print stack trace in external format
1913   void print_stack_on(outputStream* st);
1914   void print_stack() { print_stack_on(tty); }
1915 
1916   // Print stack traces in various internal formats
1917   void trace_stack()                             PRODUCT_RETURN;
1918   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1919   void trace_frames()                            PRODUCT_RETURN;
1920   void trace_oops()                              PRODUCT_RETURN;
1921 
1922   // Print an annotated view of the stack frames
1923   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1924   void validate_frame_layout() {
1925     print_frame_layout(0, true);
1926   }
1927 
1928   // Returns the number of stack frames on the stack
1929   int depth() const;
1930 
1931   // Function for testing deoptimization
1932   void deoptimize();
1933   void make_zombies();
1934 
1935   void deoptimized_wrt_marked_nmethods();
1936 
1937  public:
1938   // Returns the running thread as a JavaThread
1939   static inline JavaThread* current();
1940 
1941   // Returns the active Java thread.  Do not use this if you know you are calling
1942   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1943   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1944   // operation.  You may not want that either.
1945   static JavaThread* active();
1946 
1947   inline CompilerThread* as_CompilerThread();
1948 
1949  protected:
1950   virtual void pre_run();
1951   virtual void run();
1952   void thread_main_inner();
1953   virtual void post_run();
1954 
1955 
1956  private:
1957   GrowableArray<oop>* _array_for_gc;
1958  public:
1959 
1960   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1961 
1962  public:
1963   // Thread local information maintained by JVMTI.
1964   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1965   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1966   // getter is used to get this JavaThread's JvmtiThreadState if it has
1967   // one which means NULL can be returned. JvmtiThreadState::state_for()
1968   // is used to get the specified JavaThread's JvmtiThreadState if it has
1969   // one or it allocates a new JvmtiThreadState for the JavaThread and
1970   // returns it. JvmtiThreadState::state_for() will return NULL only if
1971   // the specified JavaThread is exiting.
1972   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1973   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1974 
1975   // JVMTI PopFrame support
1976   // Setting and clearing popframe_condition
1977   // All of these enumerated values are bits. popframe_pending
1978   // indicates that a PopFrame() has been requested and not yet been
1979   // completed. popframe_processing indicates that that PopFrame() is in
1980   // the process of being completed. popframe_force_deopt_reexecution_bit
1981   // indicates that special handling is required when returning to a
1982   // deoptimized caller.
1983   enum PopCondition {
1984     popframe_inactive                      = 0x00,
1985     popframe_pending_bit                   = 0x01,
1986     popframe_processing_bit                = 0x02,
1987     popframe_force_deopt_reexecution_bit   = 0x04
1988   };
1989   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1990   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1991   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1992   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1993   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1994   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1995   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1996   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1997 #ifdef CC_INTERP
1998   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1999   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
2000   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
2001   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
2002   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
2003 #endif
2004 
2005   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
2006   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
2007   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
2008 
2009  private:
2010   // Saved incoming arguments to popped frame.
2011   // Used only when popped interpreted frame returns to deoptimized frame.
2012   void*    _popframe_preserved_args;
2013   int      _popframe_preserved_args_size;
2014 
2015  public:
2016   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
2017   void* popframe_preserved_args();
2018   ByteSize popframe_preserved_args_size();
2019   WordSize popframe_preserved_args_size_in_words();
2020   void  popframe_free_preserved_args();
2021 
2022 
2023  private:
2024   JvmtiThreadState *_jvmti_thread_state;
2025 
2026   // Used by the interpreter in fullspeed mode for frame pop, method
2027   // entry, method exit and single stepping support. This field is
2028   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
2029   // It can be set to zero asynchronously (i.e., without a VM operation
2030   // or a lock) so we have to be very careful.
2031   int               _interp_only_mode;
2032 
2033  public:
2034   // used by the interpreter for fullspeed debugging support (see above)
2035   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2036   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
2037   int get_interp_only_mode()                { return _interp_only_mode; }
2038   void increment_interp_only_mode()         { ++_interp_only_mode; }
2039   void decrement_interp_only_mode()         { --_interp_only_mode; }
2040 
2041   // support for cached flag that indicates whether exceptions need to be posted for this thread
2042   // if this is false, we can avoid deoptimizing when events are thrown
2043   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2044  private:
2045   int    _should_post_on_exceptions_flag;
2046 
2047  public:
2048   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
2049   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
2050 
2051  private:
2052   ThreadStatistics *_thread_stat;
2053 
2054  public:
2055   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
2056 
2057   // Return a blocker object for which this thread is blocked parking.
2058   oop current_park_blocker();
2059 
2060  private:
2061   static size_t _stack_size_at_create;
2062 
2063  public:
2064   static inline size_t stack_size_at_create(void) {
2065     return _stack_size_at_create;
2066   }
2067   static inline void set_stack_size_at_create(size_t value) {
2068     _stack_size_at_create = value;
2069   }
2070 
2071   // Machine dependent stuff
2072 #include OS_CPU_HEADER(thread)
2073 
2074  public:
2075   void set_blocked_on_compilation(bool value) {
2076     _blocked_on_compilation = value;
2077   }
2078 
2079   bool blocked_on_compilation() {
2080     return _blocked_on_compilation;
2081   }
2082  protected:
2083   bool         _blocked_on_compilation;
2084 
2085 
2086   // JSR166 per-thread parker
2087  private:
2088   Parker*    _parker;
2089  public:
2090   Parker*     parker() { return _parker; }
2091 
2092   // Biased locking support
2093  private:
2094   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2095  public:
2096   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2097   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2098 
2099   // clearing/querying jni attach status
2100   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2101   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2102   inline void set_done_attaching_via_jni();
2103 
2104   // Stack dump assistance:
2105   // Track the class we want to initialize but for which we have to wait
2106   // on its init_lock() because it is already being initialized.
2107   void set_class_to_be_initialized(InstanceKlass* k);
2108   InstanceKlass* class_to_be_initialized() const;
2109 
2110 private:
2111   InstanceKlass* _class_to_be_initialized;
2112 
2113 };
2114 
2115 // Inline implementation of JavaThread::current
2116 inline JavaThread* JavaThread::current() {
2117   Thread* thread = Thread::current();
2118   assert(thread->is_Java_thread(), "just checking");
2119   return (JavaThread*)thread;
2120 }
2121 
2122 inline CompilerThread* JavaThread::as_CompilerThread() {
2123   assert(is_Compiler_thread(), "just checking");
2124   return (CompilerThread*)this;
2125 }
2126 
2127 // Dedicated thread to sweep the code cache
2128 class CodeCacheSweeperThread : public JavaThread {
2129   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2130  public:
2131   CodeCacheSweeperThread();
2132   // Track the nmethod currently being scanned by the sweeper
2133   void set_scanned_compiled_method(CompiledMethod* cm) {
2134     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2135     _scanned_compiled_method = cm;
2136   }
2137 
2138   // Hide sweeper thread from external view.
2139   bool is_hidden_from_external_view() const { return true; }
2140 
2141   bool is_Code_cache_sweeper_thread() const { return true; }
2142 
2143   // Prevent GC from unloading _scanned_compiled_method
2144   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2145   void nmethods_do(CodeBlobClosure* cf);
2146 };
2147 
2148 // A thread used for Compilation.
2149 class CompilerThread : public JavaThread {
2150   friend class VMStructs;
2151  private:
2152   CompilerCounters* _counters;
2153 
2154   ciEnv*                _env;
2155   CompileLog*           _log;
2156   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2157   CompileQueue*         _queue;
2158   BufferBlob*           _buffer_blob;
2159 
2160   AbstractCompiler*     _compiler;
2161   TimeStamp             _idle_time;
2162 
2163  public:
2164 
2165   static CompilerThread* current();
2166 
2167   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2168   ~CompilerThread();
2169 
2170   bool is_Compiler_thread() const                { return true; }
2171 
2172   virtual bool can_call_java() const;
2173 
2174   // Hide native compiler threads from external view.
2175   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2176 
2177   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2178   AbstractCompiler* compiler() const             { return _compiler; }
2179 
2180   CompileQueue* queue()        const             { return _queue; }
2181   CompilerCounters* counters() const             { return _counters; }
2182 
2183   // Get/set the thread's compilation environment.
2184   ciEnv*        env()                            { return _env; }
2185   void          set_env(ciEnv* env)              { _env = env; }
2186 
2187   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2188   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2189 
2190   // Get/set the thread's logging information
2191   CompileLog*   log()                            { return _log; }
2192   void          init_log(CompileLog* log) {
2193     // Set once, for good.
2194     assert(_log == NULL, "set only once");
2195     _log = log;
2196   }
2197 
2198   void start_idle_timer()                        { _idle_time.update(); }
2199   jlong idle_time_millis() {
2200     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2201   }
2202 
2203 #ifndef PRODUCT
2204  private:
2205   IdealGraphPrinter *_ideal_graph_printer;
2206  public:
2207   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2208   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2209 #endif
2210 
2211   // Get/set the thread's current task
2212   CompileTask* task()                      { return _task; }
2213   void         set_task(CompileTask* task) { _task = task; }
2214 };
2215 
2216 inline CompilerThread* CompilerThread::current() {
2217   return JavaThread::current()->as_CompilerThread();
2218 }
2219 
2220 // The active thread queue. It also keeps track of the current used
2221 // thread priorities.
2222 class Threads: AllStatic {
2223   friend class VMStructs;
2224  private:
2225   static int         _number_of_threads;
2226   static int         _number_of_non_daemon_threads;
2227   static int         _return_code;
2228   static uintx       _thread_claim_token;
2229 #ifdef ASSERT
2230   static bool        _vm_complete;
2231 #endif
2232 
2233   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2234   static void initialize_jsr292_core_classes(TRAPS);
2235 
2236  public:
2237   // Thread management
2238   // force_daemon is a concession to JNI, where we may need to add a
2239   // thread to the thread list before allocating its thread object
2240   static void add(JavaThread* p, bool force_daemon = false);
2241   static void remove(JavaThread* p, bool is_daemon);
2242   static void non_java_threads_do(ThreadClosure* tc);
2243   static void java_threads_do(ThreadClosure* tc);
2244   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2245   static void threads_do(ThreadClosure* tc);
2246   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2247 
2248   // Initializes the vm and creates the vm thread
2249   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2250   static void convert_vm_init_libraries_to_agents();
2251   static void create_vm_init_libraries();
2252   static void create_vm_init_agents();
2253   static void shutdown_vm_agents();
2254   static bool destroy_vm();
2255   // Supported VM versions via JNI
2256   // Includes JNI_VERSION_1_1
2257   static jboolean is_supported_jni_version_including_1_1(jint version);
2258   // Does not include JNI_VERSION_1_1
2259   static jboolean is_supported_jni_version(jint version);
2260 
2261   // The "thread claim token" provides a way for threads to be claimed
2262   // by parallel worker tasks.
2263   //
2264   // Each thread contains a "token" field. A task will claim the
2265   // thread only if its token is different from the global token,
2266   // which is updated by calling change_thread_claim_token().  When
2267   // a thread is claimed, it's token is set to the global token value
2268   // so other threads in the same iteration pass won't claim it.
2269   //
2270   // For this to work change_thread_claim_token() needs to be called
2271   // exactly once in sequential code before starting parallel tasks
2272   // that should claim threads.
2273   //
2274   // New threads get their token set to 0 and change_thread_claim_token()
2275   // never sets the global token to 0.
2276   static uintx thread_claim_token() { return _thread_claim_token; }
2277   static void change_thread_claim_token();
2278   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2279 
2280   // Apply "f->do_oop" to all root oops in all threads.
2281   // This version may only be called by sequential code.
2282   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2283   // This version may be called by sequential or parallel code.
2284   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2285 
2286   // Apply "f->do_oop" to roots in all threads that
2287   // are part of compiled frames
2288   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2289 
2290   static void convert_hcode_pointers();
2291   static void restore_hcode_pointers();
2292 
2293   // Sweeper
2294   static void nmethods_do(CodeBlobClosure* cf);
2295 
2296   // RedefineClasses support
2297   static void metadata_do(MetadataClosure* f);
2298   static void metadata_handles_do(void f(Metadata*));
2299 
2300 #ifdef ASSERT
2301   static bool is_vm_complete() { return _vm_complete; }
2302 #endif // ASSERT
2303 
2304   // Verification
2305   static void verify();
2306   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2307   static void print(bool print_stacks, bool internal_format) {
2308     // this function is only used by debug.cpp
2309     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2310   }
2311   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2312   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2313                              int buflen, bool* found_current);
2314   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2315 
2316   // Get Java threads that are waiting to enter a monitor.
2317   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2318                                                          int count, address monitor);
2319 
2320   // Get owning Java thread from the monitor's owner field.
2321   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2322                                                       address owner);
2323 
2324   // Number of threads on the active threads list
2325   static int number_of_threads()                 { return _number_of_threads; }
2326   // Number of non-daemon threads on the active threads list
2327   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2328 
2329   // Deoptimizes all frames tied to marked nmethods
2330   static void deoptimized_wrt_marked_nmethods();
2331 
2332   struct Test;                  // For private gtest access.
2333 };
2334 
2335 
2336 // Thread iterator
2337 class ThreadClosure: public StackObj {
2338  public:
2339   virtual void do_thread(Thread* thread) = 0;
2340 };
2341 
2342 class SignalHandlerMark: public StackObj {
2343  private:
2344   Thread* _thread;
2345  public:
2346   SignalHandlerMark(Thread* t) {
2347     _thread = t;
2348     if (_thread) _thread->enter_signal_handler();
2349   }
2350   ~SignalHandlerMark() {
2351     if (_thread) _thread->leave_signal_handler();
2352     _thread = NULL;
2353   }
2354 };
2355 
2356 
2357 #endif // SHARE_RUNTIME_THREAD_HPP