1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_RUNTIME_THREAD_HPP
  26 #define SHARE_RUNTIME_THREAD_HPP
  27 
  28 #include "jni.h"
  29 #include "code/compiledMethod.hpp"
  30 #include "gc/shared/gcThreadLocalData.hpp"
  31 #include "gc/shared/threadLocalAllocBuffer.hpp"
  32 #include "memory/allocation.hpp"
  33 #include "oops/oop.hpp"
  34 #include "prims/jvmtiExport.hpp"
  35 #include "runtime/frame.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/handshake.hpp"
  38 #include "runtime/javaFrameAnchor.hpp"
  39 #include "runtime/jniHandles.hpp"
  40 #include "runtime/mutexLocker.hpp"
  41 #include "runtime/os.hpp"
  42 #include "runtime/osThread.hpp"
  43 #include "runtime/park.hpp"
  44 #include "runtime/stubRoutines.hpp"
  45 #include "runtime/threadHeapSampler.hpp"
  46 #include "runtime/threadLocalStorage.hpp"
  47 #include "runtime/threadStatisticalInfo.hpp"
  48 #include "runtime/unhandledOops.hpp"
  49 #include "utilities/align.hpp"
  50 #include "utilities/exceptions.hpp"
  51 #include "utilities/macros.hpp"
  52 #ifdef ZERO
  53 # include "stack_zero.hpp"
  54 #endif
  55 #if INCLUDE_JFR
  56 #include "jfr/support/jfrThreadExtension.hpp"
  57 #endif
  58 
  59 
  60 class SafeThreadsListPtr;
  61 class ThreadSafepointState;
  62 class ThreadsList;
  63 class ThreadsSMRSupport;
  64 
  65 class JvmtiThreadState;
  66 class ThreadStatistics;
  67 class ConcurrentLocksDump;
  68 class ParkEvent;
  69 class Parker;
  70 class MonitorInfo;
  71 
  72 class ciEnv;
  73 class CompileThread;
  74 class CompileLog;
  75 class CompileTask;
  76 class CompileQueue;
  77 class CompilerCounters;
  78 
  79 class vframeArray;
  80 class vframe;
  81 class javaVFrame;
  82 
  83 class DeoptResourceMark;
  84 class jvmtiDeferredLocalVariableSet;
  85 
  86 class GCTaskQueue;
  87 class ThreadClosure;
  88 class ICRefillVerifier;
  89 class IdealGraphPrinter;
  90 
  91 class Metadata;
  92 class ResourceArea;
  93 
  94 DEBUG_ONLY(class ResourceMark;)
  95 
  96 class WorkerThread;
  97 
  98 // Class hierarchy
  99 // - Thread
 100 //   - JavaThread
 101 //     - various subclasses eg CompilerThread, ServiceThread
 102 //   - NonJavaThread
 103 //     - NamedThread
 104 //       - VMThread
 105 //       - ConcurrentGCThread
 106 //       - WorkerThread
 107 //         - GangWorker
 108 //         - GCTaskThread
 109 //     - WatcherThread
 110 //     - JfrThreadSampler
 111 //
 112 // All Thread subclasses must be either JavaThread or NonJavaThread.
 113 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 114 // a partially constructed/destroyed Thread.
 115 
 116 // Thread execution sequence and actions:
 117 // All threads:
 118 //  - thread_native_entry  // per-OS native entry point
 119 //    - stack initialization
 120 //    - other OS-level initialization (signal masks etc)
 121 //    - handshake with creating thread (if not started suspended)
 122 //    - this->call_run()  // common shared entry point
 123 //      - shared common initialization
 124 //      - this->pre_run()  // virtual per-thread-type initialization
 125 //      - this->run()      // virtual per-thread-type "main" logic
 126 //      - shared common tear-down
 127 //      - this->post_run()  // virtual per-thread-type tear-down
 128 //      - // 'this' no longer referenceable
 129 //    - OS-level tear-down (minimal)
 130 //    - final logging
 131 //
 132 // For JavaThread:
 133 //   - this->run()  // virtual but not normally overridden
 134 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 135 //       - this->entry_point()  // set differently for each kind of JavaThread
 136 
 137 class Thread: public ThreadShadow {
 138   friend class VMStructs;
 139   friend class JVMCIVMStructs;
 140  private:
 141 
 142 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 143   // Current thread is maintained as a thread-local variable
 144   static THREAD_LOCAL_DECL Thread* _thr_current;
 145 #endif
 146 
 147   // Thread local data area available to the GC. The internal
 148   // structure and contents of this data area is GC-specific.
 149   // Only GC and GC barrier code should access this data area.
 150   GCThreadLocalData _gc_data;
 151 
 152  public:
 153   static ByteSize gc_data_offset() {
 154     return byte_offset_of(Thread, _gc_data);
 155   }
 156 
 157   template <typename T> T* gc_data() {
 158     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 159     return reinterpret_cast<T*>(&_gc_data);
 160   }
 161 
 162   // Exception handling
 163   // (Note: _pending_exception and friends are in ThreadShadow)
 164   //oop       _pending_exception;                // pending exception for current thread
 165   // const char* _exception_file;                   // file information for exception (debugging only)
 166   // int         _exception_line;                   // line information for exception (debugging only)
 167  protected:
 168 
 169   DEBUG_ONLY(static Thread* _starting_thread;)
 170 
 171   // Support for forcing alignment of thread objects for biased locking
 172   void*       _real_malloc_address;
 173 
 174   // JavaThread lifecycle support:
 175   friend class SafeThreadsListPtr;  // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
 176   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 177   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 178   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 179   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 180 
 181   ThreadsList* volatile _threads_hazard_ptr;
 182   SafeThreadsListPtr*   _threads_list_ptr;
 183   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 184   ThreadsList*          get_threads_hazard_ptr();
 185   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 186   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 187     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 188   }
 189   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 190     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 191   }
 192   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 193     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 194   }
 195   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 196   uint _nested_threads_hazard_ptr_cnt;
 197   void dec_nested_threads_hazard_ptr_cnt() {
 198     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 199     _nested_threads_hazard_ptr_cnt--;
 200   }
 201   void inc_nested_threads_hazard_ptr_cnt() {
 202     _nested_threads_hazard_ptr_cnt++;
 203   }
 204   uint nested_threads_hazard_ptr_cnt() {
 205     return _nested_threads_hazard_ptr_cnt;
 206   }
 207 
 208  public:
 209   void* operator new(size_t size) throw() { return allocate(size, true); }
 210   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 211     return allocate(size, false); }
 212   void  operator delete(void* p);
 213 
 214  protected:
 215   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 216  private:
 217 
 218   // ***************************************************************
 219   // Suspend and resume support
 220   // ***************************************************************
 221   //
 222   // VM suspend/resume no longer exists - it was once used for various
 223   // things including safepoints but was deprecated and finally removed
 224   // in Java 7. Because VM suspension was considered "internal" Java-level
 225   // suspension was considered "external", and this legacy naming scheme
 226   // remains.
 227   //
 228   // External suspend/resume requests come from JVM_SuspendThread,
 229   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 230   // ResumeThread. External
 231   // suspend requests cause _external_suspend to be set and external
 232   // resume requests cause _external_suspend to be cleared.
 233   // External suspend requests do not nest on top of other external
 234   // suspend requests. The higher level APIs reject suspend requests
 235   // for already suspended threads.
 236   //
 237   // The external_suspend
 238   // flag is checked by has_special_runtime_exit_condition() and java thread
 239   // will self-suspend when handle_special_runtime_exit_condition() is
 240   // called. Most uses of the _thread_blocked state in JavaThreads are
 241   // considered the same as being externally suspended; if the blocking
 242   // condition lifts, the JavaThread will self-suspend. Other places
 243   // where VM checks for external_suspend include:
 244   //   + mutex granting (do not enter monitors when thread is suspended)
 245   //   + state transitions from _thread_in_native
 246   //
 247   // In general, java_suspend() does not wait for an external suspend
 248   // request to complete. When it returns, the only guarantee is that
 249   // the _external_suspend field is true.
 250   //
 251   // wait_for_ext_suspend_completion() is used to wait for an external
 252   // suspend request to complete. External suspend requests are usually
 253   // followed by some other interface call that requires the thread to
 254   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 255   // the interface that requires quiescence, we give the JavaThread a
 256   // chance to self-suspend before we need it to be quiescent. This
 257   // improves overall suspend/query performance.
 258   //
 259   // _suspend_flags controls the behavior of java_ suspend/resume.
 260   // It must be set under the protection of SR_lock. Read from the flag is
 261   // OK without SR_lock as long as the value is only used as a hint.
 262   // (e.g., check _external_suspend first without lock and then recheck
 263   // inside SR_lock and finish the suspension)
 264   //
 265   // _suspend_flags is also overloaded for other "special conditions" so
 266   // that a single check indicates whether any special action is needed
 267   // eg. for async exceptions.
 268   // -------------------------------------------------------------------
 269   // Notes:
 270   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 271   // but we still update its value to keep other part of the system (mainly
 272   // JVMTI) happy. ThreadState is legacy code (see notes in
 273   // osThread.hpp).
 274   //
 275   // 2. It would be more natural if set_external_suspend() is private and
 276   // part of java_suspend(), but that probably would affect the suspend/query
 277   // performance. Need more investigation on this.
 278 
 279   // suspend/resume lock: used for self-suspend
 280   Monitor* _SR_lock;
 281 
 282  protected:
 283   enum SuspendFlags {
 284     // NOTE: avoid using the sign-bit as cc generates different test code
 285     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 286 
 287     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 288     _ext_suspended          = 0x40000000U, // thread has self-suspended
 289     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 290 
 291     _has_async_exception    = 0x00000001U, // there is a pending async exception
 292     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 293 
 294     _trace_flag             = 0x00000004U  // call tracing backend
 295   };
 296 
 297   // various suspension related flags - atomically updated
 298   // overloaded for async exception checking in check_special_condition_for_native_trans.
 299   volatile uint32_t _suspend_flags;
 300 
 301  private:
 302   int _num_nested_signal;
 303 
 304   DEBUG_ONLY(bool _suspendible_thread;)
 305 
 306  public:
 307   void enter_signal_handler() { _num_nested_signal++; }
 308   void leave_signal_handler() { _num_nested_signal--; }
 309   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 310 
 311   // Determines if a heap allocation failure will be retried
 312   // (e.g., by deoptimizing and re-executing in the interpreter).
 313   // In this case, the failed allocation must raise
 314   // Universe::out_of_memory_error_retry() and omit side effects
 315   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 316   // and -XX:OnOutOfMemoryError.
 317   virtual bool in_retryable_allocation() const { return false; }
 318 
 319 #ifdef ASSERT
 320   void set_suspendible_thread() {
 321     _suspendible_thread = true;
 322   }
 323 
 324   void clear_suspendible_thread() {
 325     _suspendible_thread = false;
 326   }
 327 
 328   bool is_suspendible_thread() { return _suspendible_thread; }
 329 #endif
 330 
 331  private:
 332   // Active_handles points to a block of handles
 333   JNIHandleBlock* _active_handles;
 334 
 335   // One-element thread local free list
 336   JNIHandleBlock* _free_handle_block;
 337 
 338   // Point to the last handle mark
 339   HandleMark* _last_handle_mark;
 340 
 341   // Claim value for parallel iteration over threads.
 342   uintx _threads_do_token;
 343 
 344   // Support for GlobalCounter
 345  private:
 346   volatile uintx _rcu_counter;
 347  public:
 348   volatile uintx* get_rcu_counter() {
 349     return &_rcu_counter;
 350   }
 351 
 352  public:
 353   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 354   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 355  private:
 356 
 357 #ifdef ASSERT
 358   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 359 
 360  public:
 361   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 362     return _missed_ic_stub_refill_verifier;
 363   }
 364 
 365   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 366     _missed_ic_stub_refill_verifier = verifier;
 367   }
 368 #endif
 369 
 370  private:
 371 
 372   // debug support for checking if code does allow safepoints or not
 373   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 374   // mutex, or blocking on an object synchronizer (Java locking).
 375   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 376   // If !allow_allocation(), then an assertion failure will happen during allocation
 377   // (Hence, !allow_safepoint() => !allow_allocation()).
 378   //
 379   // The two classes NoSafepointVerifier and No_Allocation_Verifier are used to set these counters.
 380   //
 381   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 382   debug_only(int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 383 
 384   // Used by SkipGCALot class.
 385   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 386 
 387   friend class NoAllocVerifier;
 388   friend class NoSafepointVerifier;
 389   friend class PauseNoSafepointVerifier;
 390   friend class GCLocker;
 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   // Casts
 496   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 497 
 498   virtual char* name() const { return (char*)"Unknown thread"; }
 499 
 500   // Returns the current thread (ASSERTS if NULL)
 501   static inline Thread* current();
 502   // Returns the current thread, or NULL if not attached
 503   static inline Thread* current_or_null();
 504   // Returns the current thread, or NULL if not attached, and is
 505   // safe for use from signal-handlers
 506   static inline Thread* current_or_null_safe();
 507 
 508   // Common thread operations
 509 #ifdef ASSERT
 510   static void check_for_dangling_thread_pointer(Thread *thread);
 511 #endif
 512   static void set_priority(Thread* thread, ThreadPriority priority);
 513   static ThreadPriority get_priority(const Thread* const thread);
 514   static void start(Thread* thread);
 515   static void interrupt(Thread* thr);
 516   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 517 
 518   void set_native_thread_name(const char *name) {
 519     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 520     os::set_native_thread_name(name);
 521   }
 522 
 523   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 524   Monitor* SR_lock() const                       { return _SR_lock; }
 525 
 526   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 527 
 528   inline void set_suspend_flag(SuspendFlags f);
 529   inline void clear_suspend_flag(SuspendFlags f);
 530 
 531   inline void set_has_async_exception();
 532   inline void clear_has_async_exception();
 533 
 534   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 535 
 536   inline void set_critical_native_unlock();
 537   inline void clear_critical_native_unlock();
 538 
 539   inline void set_trace_flag();
 540   inline void clear_trace_flag();
 541 
 542   // Support for Unhandled Oop detection
 543   // Add the field for both, fastdebug and debug, builds to keep
 544   // Thread's fields layout the same.
 545   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 546 #ifdef CHECK_UNHANDLED_OOPS
 547  private:
 548   UnhandledOops* _unhandled_oops;
 549 #elif defined(ASSERT)
 550  private:
 551   void* _unhandled_oops;
 552 #endif
 553 #ifdef CHECK_UNHANDLED_OOPS
 554  public:
 555   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 556   // Mark oop safe for gc.  It may be stack allocated but won't move.
 557   void allow_unhandled_oop(oop *op) {
 558     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 559   }
 560   // Clear oops at safepoint so crashes point to unhandled oop violator
 561   void clear_unhandled_oops() {
 562     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 563   }
 564 #endif // CHECK_UNHANDLED_OOPS
 565 
 566  public:
 567 #ifndef PRODUCT
 568   bool skip_gcalot()           { return _skip_gcalot; }
 569   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 570 #endif
 571 
 572   // Installs a pending exception to be inserted later
 573   static void send_async_exception(oop thread_oop, oop java_throwable);
 574 
 575   // Resource area
 576   ResourceArea* resource_area() const            { return _resource_area; }
 577   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 578 
 579   OSThread* osthread() const                     { return _osthread;   }
 580   void set_osthread(OSThread* thread)            { _osthread = thread; }
 581 
 582   // JNI handle support
 583   JNIHandleBlock* active_handles() const         { return _active_handles; }
 584   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 585   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 586   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 587 
 588   // Internal handle support
 589   HandleArea* handle_area() const                { return _handle_area; }
 590   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 591 
 592   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 593   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 594 
 595   // Thread-Local Allocation Buffer (TLAB) support
 596   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 597   void initialize_tlab() {
 598     if (UseTLAB) {
 599       tlab().initialize();
 600     }
 601   }
 602 
 603   jlong allocated_bytes()               { return _allocated_bytes; }
 604   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 605   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 606   inline jlong cooked_allocated_bytes();
 607 
 608   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 609 
 610   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 611 
 612   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 613 
 614   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 615 
 616   // VM operation support
 617   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 618   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 619   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 620 
 621   // For tracking the heavyweight monitor the thread is pending on.
 622   ObjectMonitor* current_pending_monitor() {
 623     return _current_pending_monitor;
 624   }
 625   void set_current_pending_monitor(ObjectMonitor* monitor) {
 626     _current_pending_monitor = monitor;
 627   }
 628   void set_current_pending_monitor_is_from_java(bool from_java) {
 629     _current_pending_monitor_is_from_java = from_java;
 630   }
 631   bool current_pending_monitor_is_from_java() {
 632     return _current_pending_monitor_is_from_java;
 633   }
 634 
 635   // For tracking the ObjectMonitor on which this thread called Object.wait()
 636   ObjectMonitor* current_waiting_monitor() {
 637     return _current_waiting_monitor;
 638   }
 639   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 640     _current_waiting_monitor = monitor;
 641   }
 642 
 643   // GC support
 644   // Apply "f->do_oop" to all root oops in "this".
 645   //   Used by JavaThread::oops_do.
 646   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 647   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 648 
 649   // Handles the parallel case for claim_threads_do.
 650  private:
 651   bool claim_par_threads_do(uintx claim_token);
 652  public:
 653   // Requires that "claim_token" is that of the current iteration.
 654   // If "is_par" is false, sets the token of "this" to
 655   // "claim_token", and returns "true".  If "is_par" is true,
 656   // uses an atomic instruction to set the current thread's token to
 657   // "claim_token", if it is not already.  Returns "true" iff the
 658   // calling thread does the update, this indicates that the calling thread
 659   // has claimed the thread in the current iteration.
 660   bool claim_threads_do(bool is_par, uintx claim_token) {
 661     if (!is_par) {
 662       _threads_do_token = claim_token;
 663       return true;
 664     } else {
 665       return claim_par_threads_do(claim_token);
 666     }
 667   }
 668 
 669   uintx threads_do_token() const { return _threads_do_token; }
 670 
 671   // jvmtiRedefineClasses support
 672   void metadata_handles_do(void f(Metadata*));
 673 
 674   // Used by fast lock support
 675   virtual bool is_lock_owned(address adr) const;
 676 
 677   // Check if address is in the stack of the thread (not just for locks).
 678   // Warning: the method can only be used on the running thread
 679   bool is_in_stack(address adr) const;
 680   // Check if address is in the usable part of the stack (excludes protected
 681   // guard pages)
 682   bool is_in_usable_stack(address adr) const;
 683 
 684   // Sets this thread as starting thread. Returns failure if thread
 685   // creation fails due to lack of memory, too many threads etc.
 686   bool set_as_starting_thread();
 687 
 688 protected:
 689   // OS data associated with the thread
 690   OSThread* _osthread;  // Platform-specific thread information
 691 
 692   // Thread local resource area for temporary allocation within the VM
 693   ResourceArea* _resource_area;
 694 
 695   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 696 
 697   // Thread local handle area for allocation of handles within the VM
 698   HandleArea* _handle_area;
 699   GrowableArray<Metadata*>* _metadata_handles;
 700 
 701   // Support for stack overflow handling, get_thread, etc.
 702   address          _stack_base;
 703   size_t           _stack_size;
 704   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 705   int              _lgrp_id;
 706 
 707   volatile void** polling_page_addr() { return &_polling_page; }
 708 
 709  public:
 710   // Stack overflow support
 711   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 712   void    set_stack_base(address base) { _stack_base = base; }
 713   size_t  stack_size() const           { return _stack_size; }
 714   void    set_stack_size(size_t size)  { _stack_size = size; }
 715   address stack_end()  const           { return stack_base() - stack_size(); }
 716   void    record_stack_base_and_size();
 717   void    register_thread_stack_with_NMT() NOT_NMT_RETURN;
 718 
 719   bool    on_local_stack(address adr) const {
 720     // QQQ this has knowledge of direction, ought to be a stack method
 721     return (_stack_base >= adr && adr >= stack_end());
 722   }
 723 
 724   uintptr_t self_raw_id()                    { return _self_raw_id; }
 725   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 726 
 727   int     lgrp_id() const        { return _lgrp_id; }
 728   void    set_lgrp_id(int value) { _lgrp_id = value; }
 729 
 730   // Printing
 731   void print_on(outputStream* st, bool print_extended_info) const;
 732   virtual void print_on(outputStream* st) const { print_on(st, false); }
 733   void print() const { print_on(tty); }
 734   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 735   void print_value_on(outputStream* st) const;
 736 
 737   // Debug-only code
 738 #ifdef ASSERT
 739  private:
 740   // Deadlock detection support for Mutex locks. List of locks own by thread.
 741   Monitor* _owned_locks;
 742   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 743   // thus the friendship
 744   friend class Mutex;
 745   friend class Monitor;
 746 
 747  public:
 748   void print_owned_locks_on(outputStream* st) const;
 749   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 750   Monitor* owned_locks() const                   { return _owned_locks;          }
 751   bool owns_locks() const                        { return owned_locks() != NULL; }
 752   bool owns_locks_but_compiled_lock() const;
 753 
 754   // Deadlock detection
 755   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 756   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 757   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 758 #endif
 759 
 760   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 761 
 762  private:
 763   volatile int _jvmti_env_iteration_count;
 764 
 765  public:
 766   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 767   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 768   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 769 
 770   // Code generation
 771   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 772   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 773   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 774 
 775   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 776   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 777 
 778   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 779 
 780   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 781   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 782   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 783   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 784 
 785   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 786 
 787   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 788 
 789  public:
 790   volatile intptr_t _Stalled;
 791   volatile int _TypeTag;
 792   ParkEvent * _ParkEvent;                     // for synchronized()
 793   ParkEvent * _SleepEvent;                    // for Thread.sleep
 794   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 795   int NativeSyncRecursion;                    // diagnostic
 796 
 797   volatile int _OnTrap;                       // Resume-at IP delta
 798   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 799   jint _hashStateX;                           // thread-specific hashCode generator state
 800   jint _hashStateY;
 801   jint _hashStateZ;
 802 
 803   // Low-level leaf-lock primitives used to implement synchronization
 804   // and native monitor-mutex infrastructure.
 805   // Not for general synchronization use.
 806   static void SpinAcquire(volatile int * Lock, const char * Name);
 807   static void SpinRelease(volatile int * Lock);
 808   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 809   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 810   static void muxRelease(volatile intptr_t * Lock);
 811 };
 812 
 813 // Inline implementation of Thread::current()
 814 inline Thread* Thread::current() {
 815   Thread* current = current_or_null();
 816   assert(current != NULL, "Thread::current() called on detached thread");
 817   return current;
 818 }
 819 
 820 inline Thread* Thread::current_or_null() {
 821 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 822   return _thr_current;
 823 #else
 824   if (ThreadLocalStorage::is_initialized()) {
 825     return ThreadLocalStorage::thread();
 826   }
 827   return NULL;
 828 #endif
 829 }
 830 
 831 inline Thread* Thread::current_or_null_safe() {
 832   if (ThreadLocalStorage::is_initialized()) {
 833     return ThreadLocalStorage::thread();
 834   }
 835   return NULL;
 836 }
 837 
 838 class NonJavaThread: public Thread {
 839   friend class VMStructs;
 840 
 841   NonJavaThread* volatile _next;
 842 
 843   class List;
 844   static List _the_list;
 845 
 846   void add_to_the_list();
 847   void remove_from_the_list();
 848 
 849  protected:
 850   virtual void pre_run();
 851   virtual void post_run();
 852 
 853  public:
 854   NonJavaThread();
 855   ~NonJavaThread();
 856 
 857   class Iterator;
 858 };
 859 
 860 // Provides iteration over the list of NonJavaThreads.
 861 // List addition occurs in pre_run(), and removal occurs in post_run(),
 862 // so that only live fully-initialized threads can be found in the list.
 863 // Threads created after an iterator is constructed will not be visited
 864 // by the iterator. The scope of an iterator is a critical section; there
 865 // must be no safepoint checks in that scope.
 866 class NonJavaThread::Iterator : public StackObj {
 867   uint _protect_enter;
 868   NonJavaThread* _current;
 869 
 870   // Noncopyable.
 871   Iterator(const Iterator&);
 872   Iterator& operator=(const Iterator&);
 873 
 874 public:
 875   Iterator();
 876   ~Iterator();
 877 
 878   bool end() const { return _current == NULL; }
 879   NonJavaThread* current() const { return _current; }
 880   void step();
 881 };
 882 
 883 // Name support for threads.  non-JavaThread subclasses with multiple
 884 // uniquely named instances should derive from this.
 885 class NamedThread: public NonJavaThread {
 886   friend class VMStructs;
 887   enum {
 888     max_name_len = 64
 889   };
 890  private:
 891   char* _name;
 892   // log JavaThread being processed by oops_do
 893   JavaThread* _processed_thread;
 894   uint _gc_id; // The current GC id when a thread takes part in GC
 895 
 896  public:
 897   NamedThread();
 898   ~NamedThread();
 899   // May only be called once per thread.
 900   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 901   virtual bool is_Named_thread() const { return true; }
 902   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 903   JavaThread *processed_thread() { return _processed_thread; }
 904   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 905   virtual void print_on(outputStream* st) const;
 906 
 907   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 908   uint gc_id() { return _gc_id; }
 909 };
 910 
 911 // Worker threads are named and have an id of an assigned work.
 912 class WorkerThread: public NamedThread {
 913  private:
 914   uint _id;
 915  public:
 916   WorkerThread() : _id(0)               { }
 917   virtual bool is_Worker_thread() const { return true; }
 918 
 919   virtual WorkerThread* as_Worker_thread() const {
 920     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 921     return (WorkerThread*) this;
 922   }
 923 
 924   void set_id(uint work_id)             { _id = work_id; }
 925   uint id() const                       { return _id; }
 926 };
 927 
 928 // A single WatcherThread is used for simulating timer interrupts.
 929 class WatcherThread: public NonJavaThread {
 930   friend class VMStructs;
 931  protected:
 932   virtual void run();
 933 
 934  private:
 935   static WatcherThread* _watcher_thread;
 936 
 937   static bool _startable;
 938   // volatile due to at least one lock-free read
 939   volatile static bool _should_terminate;
 940  public:
 941   enum SomeConstants {
 942     delay_interval = 10                          // interrupt delay in milliseconds
 943   };
 944 
 945   // Constructor
 946   WatcherThread();
 947 
 948   // No destruction allowed
 949   ~WatcherThread() {
 950     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 951   }
 952 
 953   // Tester
 954   bool is_Watcher_thread() const                 { return true; }
 955 
 956   // Printing
 957   char* name() const { return (char*)"VM Periodic Task Thread"; }
 958   void print_on(outputStream* st) const;
 959   void unpark();
 960 
 961   // Returns the single instance of WatcherThread
 962   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 963 
 964   // Create and start the single instance of WatcherThread, or stop it on shutdown
 965   static void start();
 966   static void stop();
 967   // Only allow start once the VM is sufficiently initialized
 968   // Otherwise the first task to enroll will trigger the start
 969   static void make_startable();
 970  private:
 971   int sleep() const;
 972 };
 973 
 974 
 975 class CompilerThread;
 976 
 977 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 978 
 979 class JavaThread: public Thread {
 980   friend class VMStructs;
 981   friend class JVMCIVMStructs;
 982   friend class WhiteBox;
 983  private:
 984   JavaThread*    _next;                          // The next thread in the Threads list
 985   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 986   oop            _threadObj;                     // The Java level thread object
 987 
 988 #ifdef ASSERT
 989  private:
 990   int _java_call_counter;
 991 
 992  public:
 993   int  java_call_counter()                       { return _java_call_counter; }
 994   void inc_java_call_counter()                   { _java_call_counter++; }
 995   void dec_java_call_counter() {
 996     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 997     _java_call_counter--;
 998   }
 999  private:  // restore original namespace restriction
1000 #endif  // ifdef ASSERT
1001 
1002 #ifndef PRODUCT
1003  public:
1004   enum {
1005     jump_ring_buffer_size = 16
1006   };
1007  private:  // restore original namespace restriction
1008 #endif
1009 
1010   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
1011 
1012   ThreadFunction _entry_point;
1013 
1014   JNIEnv        _jni_environment;
1015 
1016   // Deopt support
1017   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
1018 
1019   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
1020                                                  // transition out of native
1021   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
1022   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
1023   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
1024   // Because deoptimization is lazy we must save jvmti requests to set locals
1025   // in compiled frames until we deoptimize and we have an interpreter frame.
1026   // This holds the pointer to array (yeah like there might be more than one) of
1027   // description of compiled vframes that have locals that need to be updated.
1028   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
1029 
1030   // Handshake value for fixing 6243940. We need a place for the i2c
1031   // adapter to store the callee Method*. This value is NEVER live
1032   // across a gc point so it does NOT have to be gc'd
1033   // The handshake is open ended since we can't be certain that it will
1034   // be NULLed. This is because we rarely ever see the race and end up
1035   // in handle_wrong_method which is the backend of the handshake. See
1036   // code in i2c adapters and handle_wrong_method.
1037 
1038   Method*       _callee_target;
1039 
1040   // Used to pass back results to the interpreter or generated code running Java code.
1041   oop           _vm_result;    // oop result is GC-preserved
1042   Metadata*     _vm_result_2;  // non-oop result
1043 
1044   // See ReduceInitialCardMarks: this holds the precise space interval of
1045   // the most recent slow path allocation for which compiled code has
1046   // elided card-marks for performance along the fast-path.
1047   MemRegion     _deferred_card_mark;
1048 
1049   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
1050                                                  // allocated during deoptimization
1051                                                  // and by JNI_MonitorEnter/Exit
1052 
1053   // Async. requests support
1054   enum AsyncRequests {
1055     _no_async_condition = 0,
1056     _async_exception,
1057     _async_unsafe_access_error
1058   };
1059   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1060   oop           _pending_async_exception;
1061 
1062   // Safepoint support
1063  public:                                         // Expose _thread_state for SafeFetchInt()
1064   volatile JavaThreadState _thread_state;
1065  private:
1066   ThreadSafepointState* _safepoint_state;        // Holds information about a thread during a safepoint
1067   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
1068 
1069   // JavaThread termination support
1070   enum TerminatedTypes {
1071     _not_terminated = 0xDEAD - 2,
1072     _thread_exiting,                             // JavaThread::exit() has been called for this thread
1073     _thread_terminated,                          // JavaThread is removed from thread list
1074     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
1075                                                  // only VM_Exit can set _vm_exited
1076   };
1077 
1078   // In general a JavaThread's _terminated field transitions as follows:
1079   //
1080   //   _not_terminated => _thread_exiting => _thread_terminated
1081   //
1082   // _vm_exited is a special value to cover the case of a JavaThread
1083   // executing native code after the VM itself is terminated.
1084   volatile TerminatedTypes _terminated;
1085   // suspend/resume support
1086   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1087   jint                  _in_deopt_handler;       // count of deoptimization
1088                                                  // handlers thread is in
1089   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1090   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1091                                                          // never locked) when throwing an exception. Used by interpreter only.
1092 
1093   // JNI attach states:
1094   enum JNIAttachStates {
1095     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1096     _attaching_via_jni,          // thread is attaching via JNI
1097     _attached_via_jni            // thread has attached via JNI
1098   };
1099 
1100   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1101   // A native thread that is attaching via JNI starts with a value
1102   // of _attaching_via_jni and transitions to _attached_via_jni.
1103   volatile JNIAttachStates _jni_attach_state;
1104 
1105  public:
1106   // State of the stack guard pages for this thread.
1107   enum StackGuardState {
1108     stack_guard_unused,         // not needed
1109     stack_guard_reserved_disabled,
1110     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1111     stack_guard_enabled         // enabled
1112   };
1113 
1114  private:
1115 
1116 #if INCLUDE_JVMCI
1117   // The _pending_* fields below are used to communicate extra information
1118   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1119 
1120   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1121   int       _pending_deoptimization;
1122 
1123   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1124   // before the monitor has been acquired.
1125   bool      _pending_monitorenter;
1126 
1127   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1128   bool      _pending_transfer_to_interpreter;
1129 
1130   // Guard for re-entrant call to JVMCIRuntime::adjust_comp_level
1131   bool      _adjusting_comp_level;
1132 
1133   // True if in a runtime call from compiled code that will deoptimize
1134   // and re-execute a failed heap allocation in the interpreter.
1135   bool      _in_retryable_allocation;
1136 
1137   // An id of a speculation that JVMCI compiled code can use to further describe and
1138   // uniquely identify the  speculative optimization guarded by the uncommon trap
1139   long       _pending_failed_speculation;
1140 
1141   // These fields are mutually exclusive in terms of live ranges.
1142   union {
1143     // Communicates the pc at which the most recent implicit exception occurred
1144     // from the signal handler to a deoptimization stub.
1145     address   _implicit_exception_pc;
1146 
1147     // Communicates an alternative call target to an i2c stub from a JavaCall .
1148     address   _alternate_call_target;
1149   } _jvmci;
1150 
1151   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1152   jlong*    _jvmci_counters;
1153 
1154  public:
1155   static jlong* _jvmci_old_thread_counters;
1156   static void collect_counters(typeArrayOop array);
1157  private:
1158 #endif // INCLUDE_JVMCI
1159 
1160   StackGuardState  _stack_guard_state;
1161 
1162   // Precompute the limit of the stack as used in stack overflow checks.
1163   // We load it from here to simplify the stack overflow check in assembly.
1164   address          _stack_overflow_limit;
1165   address          _reserved_stack_activation;
1166 
1167   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1168   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1169   // code)
1170   volatile oop     _exception_oop;               // Exception thrown in compiled code
1171   volatile address _exception_pc;                // PC where exception happened
1172   volatile address _exception_handler_pc;        // PC for handler of exception
1173   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1174 
1175  private:
1176   // support for JNI critical regions
1177   jint    _jni_active_critical;                  // count of entries into JNI critical region
1178 
1179   // Checked JNI: function name requires exception check
1180   char* _pending_jni_exception_check_fn;
1181 
1182   // For deadlock detection.
1183   int _depth_first_number;
1184 
1185   // JVMTI PopFrame support
1186   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1187   int _popframe_condition;
1188 
1189   // If reallocation of scalar replaced objects fails, we throw OOM
1190   // and during exception propagation, pop the top
1191   // _frames_to_pop_failed_realloc frames, the ones that reference
1192   // failed reallocations.
1193   int _frames_to_pop_failed_realloc;
1194 
1195 #ifndef PRODUCT
1196   int _jmp_ring_index;
1197   struct {
1198     // We use intptr_t instead of address so debugger doesn't try and display strings
1199     intptr_t _target;
1200     intptr_t _instruction;
1201     const char*  _file;
1202     int _line;
1203   }   _jmp_ring[jump_ring_buffer_size];
1204 #endif // PRODUCT
1205 
1206   friend class VMThread;
1207   friend class ThreadWaitTransition;
1208   friend class VM_Exit;
1209 
1210   void initialize();                             // Initialized the instance variables
1211 
1212  public:
1213   // Constructor
1214   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1215   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1216   ~JavaThread();
1217 
1218 #ifdef ASSERT
1219   // verify this JavaThread hasn't be published in the Threads::list yet
1220   void verify_not_published();
1221 #endif
1222 
1223   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1224   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1225     _jni_environment.functions = functionTable;
1226   }
1227   struct JNINativeInterface_* get_jni_functions() {
1228     return (struct JNINativeInterface_ *)_jni_environment.functions;
1229   }
1230 
1231   // This function is called at thread creation to allow
1232   // platform specific thread variables to be initialized.
1233   void cache_global_variables();
1234 
1235   // Executes Shutdown.shutdown()
1236   void invoke_shutdown_hooks();
1237 
1238   // Cleanup on thread exit
1239   enum ExitType {
1240     normal_exit,
1241     jni_detach
1242   };
1243   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1244 
1245   void cleanup_failed_attach_current_thread(bool is_daemon);
1246 
1247   // Testers
1248   virtual bool is_Java_thread() const            { return true;  }
1249   virtual bool can_call_java() const             { return true; }
1250 
1251   // Thread chain operations
1252   JavaThread* next() const                       { return _next; }
1253   void set_next(JavaThread* p)                   { _next = p; }
1254 
1255   // Thread oop. threadObj() can be NULL for initial JavaThread
1256   // (or for threads attached via JNI)
1257   oop threadObj() const                          { return _threadObj; }
1258   void set_threadObj(oop p)                      { _threadObj = p; }
1259 
1260   ThreadPriority java_priority() const;          // Read from threadObj()
1261 
1262   // Prepare thread and add to priority queue.  If a priority is
1263   // not specified, use the priority of the thread object. Threads_lock
1264   // must be held while this function is called.
1265   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1266 
1267   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1268   address saved_exception_pc()                   { return _saved_exception_pc; }
1269 
1270 
1271   ThreadFunction entry_point() const             { return _entry_point; }
1272 
1273   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1274   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1275 
1276   // Last frame anchor routines
1277 
1278   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1279 
1280   // last_Java_sp
1281   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1282   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1283 
1284   // last_Java_pc
1285 
1286   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1287 
1288   // Safepoint support
1289   inline JavaThreadState thread_state() const;
1290   inline void set_thread_state(JavaThreadState s);
1291   inline ThreadSafepointState* safepoint_state() const;
1292   inline void set_safepoint_state(ThreadSafepointState* state);
1293   inline bool is_at_poll_safepoint();
1294 
1295   // JavaThread termination and lifecycle support:
1296   void smr_delete();
1297   bool on_thread_list() const { return _on_thread_list; }
1298   void set_on_thread_list() { _on_thread_list = true; }
1299 
1300   // thread has called JavaThread::exit() or is terminated
1301   bool is_exiting() const;
1302   // thread is terminated (no longer on the threads list); we compare
1303   // against the two non-terminated values so that a freed JavaThread
1304   // will also be considered terminated.
1305   bool check_is_terminated(TerminatedTypes l_terminated) const {
1306     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1307   }
1308   bool is_terminated() const;
1309   void set_terminated(TerminatedTypes t);
1310   // special for Threads::remove() which is static:
1311   void set_terminated_value();
1312   void block_if_vm_exited();
1313 
1314   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1315   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1316 
1317   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1318   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1319 
1320   inline void set_polling_page_release(void* poll_value);
1321   inline void set_polling_page(void* poll_value);
1322   inline volatile void* get_polling_page();
1323 
1324  private:
1325   // Support for thread handshake operations
1326   HandshakeState _handshake;
1327  public:
1328   void set_handshake_operation(HandshakeOperation* op) {
1329     _handshake.set_operation(this, op);
1330   }
1331 
1332   bool has_handshake() const {
1333     return _handshake.has_operation();
1334   }
1335 
1336   void handshake_process_by_self() {
1337     _handshake.process_by_self(this);
1338   }
1339 
1340   void handshake_process_by_vmthread() {
1341     _handshake.process_by_vmthread(this);
1342   }
1343 
1344   // Suspend/resume support for JavaThread
1345  private:
1346   inline void set_ext_suspended();
1347   inline void clear_ext_suspended();
1348 
1349  public:
1350   void java_suspend(); // higher-level suspension logic called by the public APIs
1351   void java_resume();  // higher-level resume logic called by the public APIs
1352   int  java_suspend_self(); // low-level self-suspension mechanics
1353 
1354  private:
1355   // mid-level wrapper around java_suspend_self to set up correct state and
1356   // check for a pending safepoint at the end
1357   void java_suspend_self_with_safepoint_check();
1358 
1359  public:
1360   void check_and_wait_while_suspended() {
1361     assert(JavaThread::current() == this, "sanity check");
1362 
1363     bool do_self_suspend;
1364     do {
1365       // were we externally suspended while we were waiting?
1366       do_self_suspend = handle_special_suspend_equivalent_condition();
1367       if (do_self_suspend) {
1368         // don't surprise the thread that suspended us by returning
1369         java_suspend_self();
1370         set_suspend_equivalent();
1371       }
1372     } while (do_self_suspend);
1373   }
1374   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1375   // Check for async exception in addition to safepoint and suspend request.
1376   static void check_special_condition_for_native_trans(JavaThread *thread);
1377 
1378   // Same as check_special_condition_for_native_trans but finishes the
1379   // transition into thread_in_Java mode so that it can potentially
1380   // block.
1381   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1382 
1383   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1384   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1385     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1386     // Warning: is_ext_suspend_completed() may temporarily drop the
1387     // SR_lock to allow the thread to reach a stable thread state if
1388     // it is currently in a transient thread state.
1389     return is_ext_suspend_completed(false /* !called_by_wait */,
1390                                     SuspendRetryDelay, bits);
1391   }
1392 
1393   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1394   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1395   // passed as the count and delay parameters. Experiments with specific
1396   // calls to wait_for_ext_suspend_completion() can be done by passing
1397   // other values in the code. Experiments with all calls can be done
1398   // via the appropriate -XX options.
1399   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1400 
1401   // test for suspend - most (all?) of these should go away
1402   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1403 
1404   inline void set_external_suspend();
1405   inline void clear_external_suspend();
1406 
1407   inline void set_deopt_suspend();
1408   inline void clear_deopt_suspend();
1409   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1410 
1411   bool is_external_suspend() const {
1412     return (_suspend_flags & _external_suspend) != 0;
1413   }
1414   // Whenever a thread transitions from native to vm/java it must suspend
1415   // if external|deopt suspend is present.
1416   bool is_suspend_after_native() const {
1417     return (_suspend_flags & (_external_suspend | _deopt_suspend)) != 0;
1418   }
1419 
1420   // external suspend request is completed
1421   bool is_ext_suspended() const {
1422     return (_suspend_flags & _ext_suspended) != 0;
1423   }
1424 
1425   bool is_external_suspend_with_lock() const {
1426     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1427     return is_external_suspend();
1428   }
1429 
1430   // Special method to handle a pending external suspend request
1431   // when a suspend equivalent condition lifts.
1432   bool handle_special_suspend_equivalent_condition() {
1433     assert(is_suspend_equivalent(),
1434            "should only be called in a suspend equivalence condition");
1435     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1436     bool ret = is_external_suspend();
1437     if (!ret) {
1438       // not about to self-suspend so clear suspend equivalence
1439       clear_suspend_equivalent();
1440     }
1441     // implied else:
1442     // We have a pending external suspend request so we leave the
1443     // suspend_equivalent flag set until java_suspend_self() sets
1444     // the ext_suspended flag and clears the suspend_equivalent
1445     // flag. This insures that wait_for_ext_suspend_completion()
1446     // will return consistent values.
1447     return ret;
1448   }
1449 
1450   // utility methods to see if we are doing some kind of suspension
1451   bool is_being_ext_suspended() const            {
1452     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1453     return is_ext_suspended() || is_external_suspend();
1454   }
1455 
1456   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1457 
1458   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1459   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1460 
1461   // Thread.stop support
1462   void send_thread_stop(oop throwable);
1463   AsyncRequests clear_special_runtime_exit_condition() {
1464     AsyncRequests x = _special_runtime_exit_condition;
1465     _special_runtime_exit_condition = _no_async_condition;
1466     return x;
1467   }
1468 
1469   // Are any async conditions present?
1470   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1471 
1472   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1473 
1474   // these next two are also used for self-suspension and async exception support
1475   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1476 
1477   // Return true if JavaThread has an asynchronous condition or
1478   // if external suspension is requested.
1479   bool has_special_runtime_exit_condition() {
1480     // Because we don't use is_external_suspend_with_lock
1481     // it is possible that we won't see an asynchronous external suspend
1482     // request that has just gotten started, i.e., SR_lock grabbed but
1483     // _external_suspend field change either not made yet or not visible
1484     // yet. However, this is okay because the request is asynchronous and
1485     // we will see the new flag value the next time through. It's also
1486     // possible that the external suspend request is dropped after
1487     // we have checked is_external_suspend(), we will recheck its value
1488     // under SR_lock in java_suspend_self().
1489     return (_special_runtime_exit_condition != _no_async_condition) ||
1490             is_external_suspend() || is_trace_suspend();
1491   }
1492 
1493   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1494 
1495   inline void set_pending_async_exception(oop e);
1496 
1497   // Fast-locking support
1498   bool is_lock_owned(address adr) const;
1499 
1500   // Accessors for vframe array top
1501   // The linked list of vframe arrays are sorted on sp. This means when we
1502   // unpack the head must contain the vframe array to unpack.
1503   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1504   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1505 
1506   // Side structure for deferring update of java frame locals until deopt occurs
1507   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1508   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1509 
1510   // These only really exist to make debugging deopt problems simpler
1511 
1512   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1513   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1514 
1515   // The special resourceMark used during deoptimization
1516 
1517   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1518   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1519 
1520   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1521   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1522   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1523 
1524   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1525   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1526 
1527   Method*    callee_target() const               { return _callee_target; }
1528   void set_callee_target  (Method* x)          { _callee_target   = x; }
1529 
1530   // Oop results of vm runtime calls
1531   oop  vm_result() const                         { return _vm_result; }
1532   void set_vm_result  (oop x)                    { _vm_result   = x; }
1533 
1534   Metadata*    vm_result_2() const               { return _vm_result_2; }
1535   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1536 
1537   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1538   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1539 
1540 #if INCLUDE_JVMCI
1541   int  pending_deoptimization() const             { return _pending_deoptimization; }
1542   long pending_failed_speculation() const         { return _pending_failed_speculation; }
1543   bool adjusting_comp_level() const               { return _adjusting_comp_level; }
1544   void set_adjusting_comp_level(bool b)           { _adjusting_comp_level = b; }
1545   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1546   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1547   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1548   void set_pending_failed_speculation(long failed_speculation) { _pending_failed_speculation = failed_speculation; }
1549   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1550   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1551   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1552 
1553   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
1554   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
1555 #endif // INCLUDE_JVMCI
1556 
1557   // Exception handling for compiled methods
1558   oop      exception_oop() const                 { return _exception_oop; }
1559   address  exception_pc() const                  { return _exception_pc; }
1560   address  exception_handler_pc() const          { return _exception_handler_pc; }
1561   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1562 
1563   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1564   void set_exception_pc(address a)               { _exception_pc = a; }
1565   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1566   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1567 
1568   void clear_exception_oop_and_pc() {
1569     set_exception_oop(NULL);
1570     set_exception_pc(NULL);
1571   }
1572 
1573   // Stack overflow support
1574   //
1575   //  (small addresses)
1576   //
1577   //  --  <-- stack_end()                   ---
1578   //  |                                      |
1579   //  |  red pages                           |
1580   //  |                                      |
1581   //  --  <-- stack_red_zone_base()          |
1582   //  |                                      |
1583   //  |                                     guard
1584   //  |  yellow pages                       zone
1585   //  |                                      |
1586   //  |                                      |
1587   //  --  <-- stack_yellow_zone_base()       |
1588   //  |                                      |
1589   //  |                                      |
1590   //  |  reserved pages                      |
1591   //  |                                      |
1592   //  --  <-- stack_reserved_zone_base()    ---      ---
1593   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1594   //                                                  |   zone
1595   //                                                 \|/  size
1596   //  some untouched memory                          ---
1597   //
1598   //
1599   //  --
1600   //  |
1601   //  |  shadow zone
1602   //  |
1603   //  --
1604   //  x    frame n
1605   //  --
1606   //  x    frame n-1
1607   //  x
1608   //  --
1609   //  ...
1610   //
1611   //  --
1612   //  x    frame 0
1613   //  --  <-- stack_base()
1614   //
1615   //  (large addresses)
1616   //
1617 
1618  private:
1619   // These values are derived from flags StackRedPages, StackYellowPages,
1620   // StackReservedPages and StackShadowPages. The zone size is determined
1621   // ergonomically if page_size > 4K.
1622   static size_t _stack_red_zone_size;
1623   static size_t _stack_yellow_zone_size;
1624   static size_t _stack_reserved_zone_size;
1625   static size_t _stack_shadow_zone_size;
1626  public:
1627   inline size_t stack_available(address cur_sp);
1628 
1629   static size_t stack_red_zone_size() {
1630     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1631     return _stack_red_zone_size;
1632   }
1633   static void set_stack_red_zone_size(size_t s) {
1634     assert(is_aligned(s, os::vm_page_size()),
1635            "We can not protect if the red zone size is not page aligned.");
1636     assert(_stack_red_zone_size == 0, "This should be called only once.");
1637     _stack_red_zone_size = s;
1638   }
1639   address stack_red_zone_base() {
1640     return (address)(stack_end() + stack_red_zone_size());
1641   }
1642   bool in_stack_red_zone(address a) {
1643     return a <= stack_red_zone_base() && a >= stack_end();
1644   }
1645 
1646   static size_t stack_yellow_zone_size() {
1647     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1648     return _stack_yellow_zone_size;
1649   }
1650   static void set_stack_yellow_zone_size(size_t s) {
1651     assert(is_aligned(s, os::vm_page_size()),
1652            "We can not protect if the yellow zone size is not page aligned.");
1653     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1654     _stack_yellow_zone_size = s;
1655   }
1656 
1657   static size_t stack_reserved_zone_size() {
1658     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1659     return _stack_reserved_zone_size;
1660   }
1661   static void set_stack_reserved_zone_size(size_t s) {
1662     assert(is_aligned(s, os::vm_page_size()),
1663            "We can not protect if the reserved zone size is not page aligned.");
1664     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1665     _stack_reserved_zone_size = s;
1666   }
1667   address stack_reserved_zone_base() {
1668     return (address)(stack_end() +
1669                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1670   }
1671   bool in_stack_reserved_zone(address a) {
1672     return (a <= stack_reserved_zone_base()) &&
1673            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1674   }
1675 
1676   static size_t stack_yellow_reserved_zone_size() {
1677     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1678   }
1679   bool in_stack_yellow_reserved_zone(address a) {
1680     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1681   }
1682 
1683   // Size of red + yellow + reserved zones.
1684   static size_t stack_guard_zone_size() {
1685     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1686   }
1687 
1688   static size_t stack_shadow_zone_size() {
1689     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1690     return _stack_shadow_zone_size;
1691   }
1692   static void set_stack_shadow_zone_size(size_t s) {
1693     // The shadow area is not allocated or protected, so
1694     // it needs not be page aligned.
1695     // But the stack bang currently assumes that it is a
1696     // multiple of page size. This guarantees that the bang
1697     // loop touches all pages in the shadow zone.
1698     // This can be guaranteed differently, as well.  E.g., if
1699     // the page size is a multiple of 4K, banging in 4K steps
1700     // suffices to touch all pages. (Some pages are banged
1701     // several times, though.)
1702     assert(is_aligned(s, os::vm_page_size()),
1703            "Stack bang assumes multiple of page size.");
1704     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1705     _stack_shadow_zone_size = s;
1706   }
1707 
1708   void create_stack_guard_pages();
1709   void remove_stack_guard_pages();
1710 
1711   void enable_stack_reserved_zone();
1712   void disable_stack_reserved_zone();
1713   void enable_stack_yellow_reserved_zone();
1714   void disable_stack_yellow_reserved_zone();
1715   void enable_stack_red_zone();
1716   void disable_stack_red_zone();
1717 
1718   inline bool stack_guard_zone_unused();
1719   inline bool stack_yellow_reserved_zone_disabled();
1720   inline bool stack_reserved_zone_disabled();
1721   inline bool stack_guards_enabled();
1722 
1723   address reserved_stack_activation() const { return _reserved_stack_activation; }
1724   void set_reserved_stack_activation(address addr) {
1725     assert(_reserved_stack_activation == stack_base()
1726             || _reserved_stack_activation == NULL
1727             || addr == stack_base(), "Must not be set twice");
1728     _reserved_stack_activation = addr;
1729   }
1730 
1731   // Attempt to reguard the stack after a stack overflow may have occurred.
1732   // Returns true if (a) guard pages are not needed on this thread, (b) the
1733   // pages are already guarded, or (c) the pages were successfully reguarded.
1734   // Returns false if there is not enough stack space to reguard the pages, in
1735   // which case the caller should unwind a frame and try again.  The argument
1736   // should be the caller's (approximate) sp.
1737   bool reguard_stack(address cur_sp);
1738   // Similar to above but see if current stackpoint is out of the guard area
1739   // and reguard if possible.
1740   bool reguard_stack(void);
1741 
1742   address stack_overflow_limit() { return _stack_overflow_limit; }
1743   void set_stack_overflow_limit() {
1744     _stack_overflow_limit =
1745       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1746   }
1747 
1748   // Misc. accessors/mutators
1749   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1750   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1751   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1752 
1753 #ifndef PRODUCT
1754   void record_jump(address target, address instr, const char* file, int line);
1755 #endif // PRODUCT
1756 
1757   // For assembly stub generation
1758   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1759 #ifndef PRODUCT
1760   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1761   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1762 #endif // PRODUCT
1763   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1764   static ByteSize pending_jni_exception_check_fn_offset() {
1765     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1766   }
1767   static ByteSize last_Java_sp_offset() {
1768     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1769   }
1770   static ByteSize last_Java_pc_offset() {
1771     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1772   }
1773   static ByteSize frame_anchor_offset() {
1774     return byte_offset_of(JavaThread, _anchor);
1775   }
1776   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1777   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1778   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1779   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1780   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1781   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1782 #if INCLUDE_JVMCI
1783   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1784   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1785   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1786   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1787   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1788   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1789 #endif // INCLUDE_JVMCI
1790   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1791   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1792   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1793   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1794   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1795   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1796   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1797   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1798 
1799   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1800   static ByteSize should_post_on_exceptions_flag_offset() {
1801     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1802   }
1803 
1804   // Returns the jni environment for this thread
1805   JNIEnv* jni_environment()                      { return &_jni_environment; }
1806 
1807   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1808     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1809     // Only return NULL if thread is off the thread list; starting to
1810     // exit should not return NULL.
1811     if (thread_from_jni_env->is_terminated()) {
1812       thread_from_jni_env->block_if_vm_exited();
1813       return NULL;
1814     } else {
1815       return thread_from_jni_env;
1816     }
1817   }
1818 
1819   // JNI critical regions. These can nest.
1820   bool in_critical()    { return _jni_active_critical > 0; }
1821   bool in_last_critical()  { return _jni_active_critical == 1; }
1822   inline void enter_critical();
1823   void exit_critical() {
1824     assert(Thread::current() == this, "this must be current thread");
1825     _jni_active_critical--;
1826     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1827   }
1828 
1829   // Checked JNI: is the programmer required to check for exceptions, if so specify
1830   // which function name. Returning to a Java frame should implicitly clear the
1831   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1832   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1833   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1834   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1835   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1836   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1837   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1838 
1839   // For deadlock detection
1840   int depth_first_number() { return _depth_first_number; }
1841   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1842 
1843  private:
1844   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1845 
1846  public:
1847   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1848   void add_monitor_chunk(MonitorChunk* chunk);
1849   void remove_monitor_chunk(MonitorChunk* chunk);
1850   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1851   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1852   void dec_in_deopt_handler() {
1853     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1854     if (_in_deopt_handler > 0) { // robustness
1855       _in_deopt_handler--;
1856     }
1857   }
1858 
1859  private:
1860   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1861 
1862  public:
1863 
1864   // Frame iteration; calls the function f for all frames on the stack
1865   void frames_do(void f(frame*, const RegisterMap*));
1866 
1867   // Memory operations
1868   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1869 
1870   // Sweeper operations
1871   virtual void nmethods_do(CodeBlobClosure* cf);
1872 
1873   // RedefineClasses Support
1874   void metadata_do(MetadataClosure* f);
1875 
1876   // Debug method asserting thread states are correct during a handshake operation.
1877   DEBUG_ONLY(void verify_states_for_handshake();)
1878 
1879   // Misc. operations
1880   char* name() const { return (char*)get_thread_name(); }
1881   void print_on(outputStream* st, bool print_extended_info) const;
1882   void print_on(outputStream* st) const { print_on(st, false); }
1883   void print_value();
1884   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1885   void print_thread_state() const                      PRODUCT_RETURN;
1886   void print_on_error(outputStream* st, char* buf, int buflen) const;
1887   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1888   void verify();
1889   const char* get_thread_name() const;
1890  protected:
1891   // factor out low-level mechanics for use in both normal and error cases
1892   virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1893  public:
1894   const char* get_threadgroup_name() const;
1895   const char* get_parent_name() const;
1896 
1897   // Accessing frames
1898   frame last_frame() {
1899     _anchor.make_walkable(this);
1900     return pd_last_frame();
1901   }
1902   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1903 
1904   // Returns method at 'depth' java or native frames down the stack
1905   // Used for security checks
1906   Klass* security_get_caller_class(int depth);
1907 
1908   // Print stack trace in external format
1909   void print_stack_on(outputStream* st);
1910   void print_stack() { print_stack_on(tty); }
1911 
1912   // Print stack traces in various internal formats
1913   void trace_stack()                             PRODUCT_RETURN;
1914   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1915   void trace_frames()                            PRODUCT_RETURN;
1916   void trace_oops()                              PRODUCT_RETURN;
1917 
1918   // Print an annotated view of the stack frames
1919   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1920   void validate_frame_layout() {
1921     print_frame_layout(0, true);
1922   }
1923 
1924   // Returns the number of stack frames on the stack
1925   int depth() const;
1926 
1927   // Function for testing deoptimization
1928   void deoptimize();
1929   void make_zombies();
1930 
1931   void deoptimized_wrt_marked_nmethods();
1932 
1933  public:
1934   // Returns the running thread as a JavaThread
1935   static inline JavaThread* current();
1936 
1937   // Returns the active Java thread.  Do not use this if you know you are calling
1938   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1939   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1940   // operation.  You may not want that either.
1941   static JavaThread* active();
1942 
1943   inline CompilerThread* as_CompilerThread();
1944 
1945  protected:
1946   virtual void pre_run();
1947   virtual void run();
1948   void thread_main_inner();
1949   virtual void post_run();
1950 
1951 
1952  private:
1953   GrowableArray<oop>* _array_for_gc;
1954  public:
1955 
1956   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1957 
1958  public:
1959   // Thread local information maintained by JVMTI.
1960   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1961   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1962   // getter is used to get this JavaThread's JvmtiThreadState if it has
1963   // one which means NULL can be returned. JvmtiThreadState::state_for()
1964   // is used to get the specified JavaThread's JvmtiThreadState if it has
1965   // one or it allocates a new JvmtiThreadState for the JavaThread and
1966   // returns it. JvmtiThreadState::state_for() will return NULL only if
1967   // the specified JavaThread is exiting.
1968   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1969   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1970 
1971   // JVMTI PopFrame support
1972   // Setting and clearing popframe_condition
1973   // All of these enumerated values are bits. popframe_pending
1974   // indicates that a PopFrame() has been requested and not yet been
1975   // completed. popframe_processing indicates that that PopFrame() is in
1976   // the process of being completed. popframe_force_deopt_reexecution_bit
1977   // indicates that special handling is required when returning to a
1978   // deoptimized caller.
1979   enum PopCondition {
1980     popframe_inactive                      = 0x00,
1981     popframe_pending_bit                   = 0x01,
1982     popframe_processing_bit                = 0x02,
1983     popframe_force_deopt_reexecution_bit   = 0x04
1984   };
1985   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1986   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1987   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1988   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1989   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1990   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1991   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1992   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1993 #ifdef CC_INTERP
1994   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1995   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1996   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1997   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1998   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1999 #endif
2000 
2001   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
2002   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
2003   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
2004 
2005  private:
2006   // Saved incoming arguments to popped frame.
2007   // Used only when popped interpreted frame returns to deoptimized frame.
2008   void*    _popframe_preserved_args;
2009   int      _popframe_preserved_args_size;
2010 
2011  public:
2012   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
2013   void* popframe_preserved_args();
2014   ByteSize popframe_preserved_args_size();
2015   WordSize popframe_preserved_args_size_in_words();
2016   void  popframe_free_preserved_args();
2017 
2018 
2019  private:
2020   JvmtiThreadState *_jvmti_thread_state;
2021 
2022   // Used by the interpreter in fullspeed mode for frame pop, method
2023   // entry, method exit and single stepping support. This field is
2024   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
2025   // It can be set to zero asynchronously (i.e., without a VM operation
2026   // or a lock) so we have to be very careful.
2027   int               _interp_only_mode;
2028 
2029  public:
2030   // used by the interpreter for fullspeed debugging support (see above)
2031   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2032   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
2033   int get_interp_only_mode()                { return _interp_only_mode; }
2034   void increment_interp_only_mode()         { ++_interp_only_mode; }
2035   void decrement_interp_only_mode()         { --_interp_only_mode; }
2036 
2037   // support for cached flag that indicates whether exceptions need to be posted for this thread
2038   // if this is false, we can avoid deoptimizing when events are thrown
2039   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2040  private:
2041   int    _should_post_on_exceptions_flag;
2042 
2043  public:
2044   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
2045   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
2046 
2047  private:
2048   ThreadStatistics *_thread_stat;
2049 
2050  public:
2051   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
2052 
2053   // Return a blocker object for which this thread is blocked parking.
2054   oop current_park_blocker();
2055 
2056  private:
2057   static size_t _stack_size_at_create;
2058 
2059  public:
2060   static inline size_t stack_size_at_create(void) {
2061     return _stack_size_at_create;
2062   }
2063   static inline void set_stack_size_at_create(size_t value) {
2064     _stack_size_at_create = value;
2065   }
2066 
2067   // Machine dependent stuff
2068 #include OS_CPU_HEADER(thread)
2069 
2070  public:
2071   void set_blocked_on_compilation(bool value) {
2072     _blocked_on_compilation = value;
2073   }
2074 
2075   bool blocked_on_compilation() {
2076     return _blocked_on_compilation;
2077   }
2078  protected:
2079   bool         _blocked_on_compilation;
2080 
2081 
2082   // JSR166 per-thread parker
2083  private:
2084   Parker*    _parker;
2085  public:
2086   Parker*     parker() { return _parker; }
2087 
2088   // Biased locking support
2089  private:
2090   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2091  public:
2092   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2093   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2094 
2095   // clearing/querying jni attach status
2096   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2097   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2098   inline void set_done_attaching_via_jni();
2099 
2100   // Stack dump assistance:
2101   // Track the class we want to initialize but for which we have to wait
2102   // on its init_lock() because it is already being initialized.
2103   void set_class_to_be_initialized(InstanceKlass* k);
2104   InstanceKlass* class_to_be_initialized() const;
2105 
2106 private:
2107   InstanceKlass* _class_to_be_initialized;
2108 
2109 };
2110 
2111 // Inline implementation of JavaThread::current
2112 inline JavaThread* JavaThread::current() {
2113   Thread* thread = Thread::current();
2114   assert(thread->is_Java_thread(), "just checking");
2115   return (JavaThread*)thread;
2116 }
2117 
2118 inline CompilerThread* JavaThread::as_CompilerThread() {
2119   assert(is_Compiler_thread(), "just checking");
2120   return (CompilerThread*)this;
2121 }
2122 
2123 // Dedicated thread to sweep the code cache
2124 class CodeCacheSweeperThread : public JavaThread {
2125   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2126  public:
2127   CodeCacheSweeperThread();
2128   // Track the nmethod currently being scanned by the sweeper
2129   void set_scanned_compiled_method(CompiledMethod* cm) {
2130     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2131     _scanned_compiled_method = cm;
2132   }
2133 
2134   // Hide sweeper thread from external view.
2135   bool is_hidden_from_external_view() const { return true; }
2136 
2137   bool is_Code_cache_sweeper_thread() const { return true; }
2138 
2139   // Prevent GC from unloading _scanned_compiled_method
2140   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2141   void nmethods_do(CodeBlobClosure* cf);
2142 };
2143 
2144 // A thread used for Compilation.
2145 class CompilerThread : public JavaThread {
2146   friend class VMStructs;
2147  private:
2148   CompilerCounters* _counters;
2149 
2150   ciEnv*                _env;
2151   CompileLog*           _log;
2152   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2153   CompileQueue*         _queue;
2154   BufferBlob*           _buffer_blob;
2155 
2156   AbstractCompiler*     _compiler;
2157   TimeStamp             _idle_time;
2158 
2159  public:
2160 
2161   static CompilerThread* current();
2162 
2163   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2164   ~CompilerThread();
2165 
2166   bool is_Compiler_thread() const                { return true; }
2167 
2168   virtual bool can_call_java() const;
2169 
2170   // Hide native compiler threads from external view.
2171   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2172 
2173   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2174   AbstractCompiler* compiler() const             { return _compiler; }
2175 
2176   CompileQueue* queue()        const             { return _queue; }
2177   CompilerCounters* counters() const             { return _counters; }
2178 
2179   // Get/set the thread's compilation environment.
2180   ciEnv*        env()                            { return _env; }
2181   void          set_env(ciEnv* env)              { _env = env; }
2182 
2183   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2184   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2185 
2186   // Get/set the thread's logging information
2187   CompileLog*   log()                            { return _log; }
2188   void          init_log(CompileLog* log) {
2189     // Set once, for good.
2190     assert(_log == NULL, "set only once");
2191     _log = log;
2192   }
2193 
2194   void start_idle_timer()                        { _idle_time.update(); }
2195   jlong idle_time_millis() {
2196     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2197   }
2198 
2199 #ifndef PRODUCT
2200  private:
2201   IdealGraphPrinter *_ideal_graph_printer;
2202  public:
2203   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2204   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2205 #endif
2206 
2207   // Get/set the thread's current task
2208   CompileTask* task()                      { return _task; }
2209   void         set_task(CompileTask* task) { _task = task; }
2210 };
2211 
2212 inline CompilerThread* CompilerThread::current() {
2213   return JavaThread::current()->as_CompilerThread();
2214 }
2215 
2216 // The active thread queue. It also keeps track of the current used
2217 // thread priorities.
2218 class Threads: AllStatic {
2219   friend class VMStructs;
2220  private:
2221   static JavaThread* _thread_list;
2222   static int         _number_of_threads;
2223   static int         _number_of_non_daemon_threads;
2224   static int         _return_code;
2225   static uintx       _thread_claim_token;
2226 #ifdef ASSERT
2227   static bool        _vm_complete;
2228 #endif
2229 
2230   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2231   static void initialize_jsr292_core_classes(TRAPS);
2232 
2233  public:
2234   // Thread management
2235   // force_daemon is a concession to JNI, where we may need to add a
2236   // thread to the thread list before allocating its thread object
2237   static void add(JavaThread* p, bool force_daemon = false);
2238   static void remove(JavaThread* p, bool is_daemon);
2239   static void non_java_threads_do(ThreadClosure* tc);
2240   static void java_threads_do(ThreadClosure* tc);
2241   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2242   static void threads_do(ThreadClosure* tc);
2243   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2244 
2245   // Initializes the vm and creates the vm thread
2246   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2247   static void convert_vm_init_libraries_to_agents();
2248   static void create_vm_init_libraries();
2249   static void create_vm_init_agents();
2250   static void shutdown_vm_agents();
2251   static bool destroy_vm();
2252   // Supported VM versions via JNI
2253   // Includes JNI_VERSION_1_1
2254   static jboolean is_supported_jni_version_including_1_1(jint version);
2255   // Does not include JNI_VERSION_1_1
2256   static jboolean is_supported_jni_version(jint version);
2257 
2258   // The "thread claim token" provides a way for threads to be claimed
2259   // by parallel worker tasks.
2260   //
2261   // Each thread contains a "token" field. A task will claim the
2262   // thread only if its token is different from the global token,
2263   // which is updated by calling change_thread_claim_token().  When
2264   // a thread is claimed, it's token is set to the global token value
2265   // so other threads in the same iteration pass won't claim it.
2266   //
2267   // For this to work change_thread_claim_token() needs to be called
2268   // exactly once in sequential code before starting parallel tasks
2269   // that should claim threads.
2270   //
2271   // New threads get their token set to 0 and change_thread_claim_token()
2272   // never sets the global token to 0.
2273   static uintx thread_claim_token() { return _thread_claim_token; }
2274   static void change_thread_claim_token();
2275   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2276 
2277   // Apply "f->do_oop" to all root oops in all threads.
2278   // This version may only be called by sequential code.
2279   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2280   // This version may be called by sequential or parallel code.
2281   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2282 
2283   // Apply "f->do_oop" to roots in all threads that
2284   // are part of compiled frames
2285   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2286 
2287   static void convert_hcode_pointers();
2288   static void restore_hcode_pointers();
2289 
2290   // Sweeper
2291   static void nmethods_do(CodeBlobClosure* cf);
2292 
2293   // RedefineClasses support
2294   static void metadata_do(MetadataClosure* f);
2295   static void metadata_handles_do(void f(Metadata*));
2296 
2297 #ifdef ASSERT
2298   static bool is_vm_complete() { return _vm_complete; }
2299 #endif // ASSERT
2300 
2301   // Verification
2302   static void verify();
2303   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2304   static void print(bool print_stacks, bool internal_format) {
2305     // this function is only used by debug.cpp
2306     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2307   }
2308   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2309   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2310                              int buflen, bool* found_current);
2311   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2312 
2313   // Get Java threads that are waiting to enter a monitor.
2314   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2315                                                          int count, address monitor);
2316 
2317   // Get owning Java thread from the monitor's owner field.
2318   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2319                                                       address owner);
2320 
2321   // Number of threads on the active threads list
2322   static int number_of_threads()                 { return _number_of_threads; }
2323   // Number of non-daemon threads on the active threads list
2324   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2325 
2326   // Deoptimizes all frames tied to marked nmethods
2327   static void deoptimized_wrt_marked_nmethods();
2328 
2329   struct Test;                  // For private gtest access.
2330 };
2331 
2332 
2333 // Thread iterator
2334 class ThreadClosure: public StackObj {
2335  public:
2336   virtual void do_thread(Thread* thread) = 0;
2337 };
2338 
2339 class SignalHandlerMark: public StackObj {
2340  private:
2341   Thread* _thread;
2342  public:
2343   SignalHandlerMark(Thread* t) {
2344     _thread = t;
2345     if (_thread) _thread->enter_signal_handler();
2346   }
2347   ~SignalHandlerMark() {
2348     if (_thread) _thread->leave_signal_handler();
2349     _thread = NULL;
2350   }
2351 };
2352 
2353 
2354 #endif // SHARE_RUNTIME_THREAD_HPP