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/continuation.hpp"
  36 #include "runtime/frame.hpp"
  37 #include "runtime/globals.hpp"
  38 #include "runtime/handshake.hpp"
  39 #include "runtime/javaFrameAnchor.hpp"
  40 #include "runtime/jniHandles.hpp"
  41 #include "runtime/mutexLocker.hpp"
  42 #include "runtime/os.hpp"
  43 #include "runtime/osThread.hpp"
  44 #include "runtime/park.hpp"
  45 #include "runtime/stubRoutines.hpp"
  46 #include "runtime/threadHeapSampler.hpp"
  47 #include "runtime/threadLocalStorage.hpp"
  48 #include "runtime/threadStatisticalInfo.hpp"
  49 #include "runtime/unhandledOops.hpp"
  50 #include "utilities/align.hpp"
  51 #include "utilities/exceptions.hpp"
  52 #include "utilities/macros.hpp"
  53 #ifdef ZERO
  54 # include "stack_zero.hpp"
  55 #endif
  56 #if INCLUDE_JFR
  57 #include "jfr/support/jfrThreadExtension.hpp"
  58 #endif
  59 
  60 
  61 class SafeThreadsListPtr;
  62 class ThreadSafepointState;
  63 class ThreadsList;
  64 class ThreadsSMRSupport;
  65 
  66 class JvmtiThreadState;
  67 class ThreadStatistics;
  68 class ConcurrentLocksDump;
  69 class ParkEvent;
  70 class Parker;
  71 class MonitorInfo;
  72 
  73 class ciEnv;
  74 class CompileThread;
  75 class CompileLog;
  76 class CompileTask;
  77 class CompileQueue;
  78 class CompilerCounters;
  79 
  80 class vframeArray;
  81 class vframe;
  82 class javaVFrame;
  83 
  84 class DeoptResourceMark;
  85 class jvmtiDeferredLocalVariableSet;
  86 
  87 class GCTaskQueue;
  88 class ThreadClosure;
  89 class ICRefillVerifier;
  90 class IdealGraphPrinter;
  91 
  92 class JVMCIEnv;
  93 class JVMCIPrimitiveArray;
  94 
  95 class Metadata;
  96 class ResourceArea;
  97 
  98 DEBUG_ONLY(class ResourceMark;)
  99 
 100 class WorkerThread;
 101 
 102 // Class hierarchy
 103 // - Thread
 104 //   - JavaThread
 105 //     - various subclasses eg CompilerThread, ServiceThread
 106 //   - NonJavaThread
 107 //     - NamedThread
 108 //       - VMThread
 109 //       - ConcurrentGCThread
 110 //       - WorkerThread
 111 //         - GangWorker
 112 //         - GCTaskThread
 113 //     - WatcherThread
 114 //     - JfrThreadSampler
 115 //
 116 // All Thread subclasses must be either JavaThread or NonJavaThread.
 117 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 118 // a partially constructed/destroyed Thread.
 119 
 120 // Thread execution sequence and actions:
 121 // All threads:
 122 //  - thread_native_entry  // per-OS native entry point
 123 //    - stack initialization
 124 //    - other OS-level initialization (signal masks etc)
 125 //    - handshake with creating thread (if not started suspended)
 126 //    - this->call_run()  // common shared entry point
 127 //      - shared common initialization
 128 //      - this->pre_run()  // virtual per-thread-type initialization
 129 //      - this->run()      // virtual per-thread-type "main" logic
 130 //      - shared common tear-down
 131 //      - this->post_run()  // virtual per-thread-type tear-down
 132 //      - // 'this' no longer referenceable
 133 //    - OS-level tear-down (minimal)
 134 //    - final logging
 135 //
 136 // For JavaThread:
 137 //   - this->run()  // virtual but not normally overridden
 138 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 139 //       - this->entry_point()  // set differently for each kind of JavaThread
 140 
 141 class Thread: public ThreadShadow {
 142   friend class VMStructs;
 143   friend class JVMCIVMStructs;
 144  private:
 145 
 146 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 147   // Current thread is maintained as a thread-local variable
 148   static THREAD_LOCAL_DECL Thread* _thr_current;
 149 #endif
 150 
 151   // Thread local data area available to the GC. The internal
 152   // structure and contents of this data area is GC-specific.
 153   // Only GC and GC barrier code should access this data area.
 154   GCThreadLocalData _gc_data;
 155 
 156  public:
 157   static ByteSize gc_data_offset() {
 158     return byte_offset_of(Thread, _gc_data);
 159   }
 160 
 161   template <typename T> T* gc_data() {
 162     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 163     return reinterpret_cast<T*>(&_gc_data);
 164   }
 165 
 166   // Exception handling
 167   // (Note: _pending_exception and friends are in ThreadShadow)
 168   //oop       _pending_exception;                // pending exception for current thread
 169   // const char* _exception_file;                   // file information for exception (debugging only)
 170   // int         _exception_line;                   // line information for exception (debugging only)
 171  protected:
 172 
 173   DEBUG_ONLY(static Thread* _starting_thread;)
 174 
 175   // Support for forcing alignment of thread objects for biased locking
 176   void*       _real_malloc_address;
 177 
 178   // JavaThread lifecycle support:
 179   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
 180   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 181   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 182   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 183   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 184 
 185   ThreadsList* volatile _threads_hazard_ptr;
 186   SafeThreadsListPtr*   _threads_list_ptr;
 187   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 188   ThreadsList*          get_threads_hazard_ptr();
 189   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 190   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 191     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 192   }
 193   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 194     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 195   }
 196   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 197     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 198   }
 199   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 200   uint _nested_threads_hazard_ptr_cnt;
 201   void dec_nested_threads_hazard_ptr_cnt() {
 202     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 203     _nested_threads_hazard_ptr_cnt--;
 204   }
 205   void inc_nested_threads_hazard_ptr_cnt() {
 206     _nested_threads_hazard_ptr_cnt++;
 207   }
 208   uint nested_threads_hazard_ptr_cnt() {
 209     return _nested_threads_hazard_ptr_cnt;
 210   }
 211 
 212  public:
 213   void* operator new(size_t size) throw() { return allocate(size, true); }
 214   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 215     return allocate(size, false); }
 216   void  operator delete(void* p);
 217 
 218  protected:
 219   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 220  private:
 221 
 222   // ***************************************************************
 223   // Suspend and resume support
 224   // ***************************************************************
 225   //
 226   // VM suspend/resume no longer exists - it was once used for various
 227   // things including safepoints but was deprecated and finally removed
 228   // in Java 7. Because VM suspension was considered "internal" Java-level
 229   // suspension was considered "external", and this legacy naming scheme
 230   // remains.
 231   //
 232   // External suspend/resume requests come from JVM_SuspendThread,
 233   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 234   // ResumeThread. External
 235   // suspend requests cause _external_suspend to be set and external
 236   // resume requests cause _external_suspend to be cleared.
 237   // External suspend requests do not nest on top of other external
 238   // suspend requests. The higher level APIs reject suspend requests
 239   // for already suspended threads.
 240   //
 241   // The external_suspend
 242   // flag is checked by has_special_runtime_exit_condition() and java thread
 243   // will self-suspend when handle_special_runtime_exit_condition() is
 244   // called. Most uses of the _thread_blocked state in JavaThreads are
 245   // considered the same as being externally suspended; if the blocking
 246   // condition lifts, the JavaThread will self-suspend. Other places
 247   // where VM checks for external_suspend include:
 248   //   + mutex granting (do not enter monitors when thread is suspended)
 249   //   + state transitions from _thread_in_native
 250   //
 251   // In general, java_suspend() does not wait for an external suspend
 252   // request to complete. When it returns, the only guarantee is that
 253   // the _external_suspend field is true.
 254   //
 255   // wait_for_ext_suspend_completion() is used to wait for an external
 256   // suspend request to complete. External suspend requests are usually
 257   // followed by some other interface call that requires the thread to
 258   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 259   // the interface that requires quiescence, we give the JavaThread a
 260   // chance to self-suspend before we need it to be quiescent. This
 261   // improves overall suspend/query performance.
 262   //
 263   // _suspend_flags controls the behavior of java_ suspend/resume.
 264   // It must be set under the protection of SR_lock. Read from the flag is
 265   // OK without SR_lock as long as the value is only used as a hint.
 266   // (e.g., check _external_suspend first without lock and then recheck
 267   // inside SR_lock and finish the suspension)
 268   //
 269   // _suspend_flags is also overloaded for other "special conditions" so
 270   // that a single check indicates whether any special action is needed
 271   // eg. for async exceptions.
 272   // -------------------------------------------------------------------
 273   // Notes:
 274   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 275   // but we still update its value to keep other part of the system (mainly
 276   // JVMTI) happy. ThreadState is legacy code (see notes in
 277   // osThread.hpp).
 278   //
 279   // 2. It would be more natural if set_external_suspend() is private and
 280   // part of java_suspend(), but that probably would affect the suspend/query
 281   // performance. Need more investigation on this.
 282 
 283   // suspend/resume lock: used for self-suspend
 284   Monitor* _SR_lock;
 285 
 286  protected:
 287   enum SuspendFlags {
 288     // NOTE: avoid using the sign-bit as cc generates different test code
 289     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 290 
 291     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 292     _ext_suspended          = 0x40000000U, // thread has self-suspended
 293 
 294     _has_async_exception    = 0x00000001U, // there is a pending async exception
 295     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 296 
 297     _trace_flag             = 0x00000004U  // call tracing backend
 298   };
 299 
 300   // various suspension related flags - atomically updated
 301   // overloaded for async exception checking in check_special_condition_for_native_trans.
 302   volatile uint32_t _suspend_flags;
 303 
 304  private:
 305   int _num_nested_signal;
 306 
 307   DEBUG_ONLY(bool _suspendible_thread;)
 308 
 309  public:
 310   void enter_signal_handler() { _num_nested_signal++; }
 311   void leave_signal_handler() { _num_nested_signal--; }
 312   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 313 
 314   // Determines if a heap allocation failure will be retried
 315   // (e.g., by deoptimizing and re-executing in the interpreter).
 316   // In this case, the failed allocation must raise
 317   // Universe::out_of_memory_error_retry() and omit side effects
 318   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 319   // and -XX:OnOutOfMemoryError.
 320   virtual bool in_retryable_allocation() const { return false; }
 321 
 322 #ifdef ASSERT
 323   void set_suspendible_thread() {
 324     _suspendible_thread = true;
 325   }
 326 
 327   void clear_suspendible_thread() {
 328     _suspendible_thread = false;
 329   }
 330 
 331   bool is_suspendible_thread() { return _suspendible_thread; }
 332 #endif
 333 
 334  private:
 335   // Active_handles points to a block of handles
 336   JNIHandleBlock* _active_handles;
 337 
 338   // One-element thread local free list
 339   JNIHandleBlock* _free_handle_block;
 340 
 341   // Point to the last handle mark
 342   HandleMark* _last_handle_mark;
 343 
 344   // Claim value for parallel iteration over threads.
 345   uintx _threads_do_token;
 346 
 347   // Support for GlobalCounter
 348  private:
 349   volatile uintx _rcu_counter;
 350  public:
 351   volatile uintx* get_rcu_counter() {
 352     return &_rcu_counter;
 353   }
 354 
 355  public:
 356   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 357   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 358  private:
 359 
 360 #ifdef ASSERT
 361   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 362 
 363  public:
 364   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 365     return _missed_ic_stub_refill_verifier;
 366   }
 367 
 368   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 369     _missed_ic_stub_refill_verifier = verifier;
 370   }
 371 #endif // ASSERT
 372 
 373  private:
 374 
 375   // Debug support for checking if code allows safepoints or not.
 376   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 377   // mutex, or blocking on an object synchronizer (Java locking).
 378   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 379   // the above cases.
 380   //
 381   // The class NoSafepointVerifier is used to set this counter.
 382   //
 383   NOT_PRODUCT(int _no_safepoint_count;)         // If 0, thread allow a safepoint to happen
 384 
 385  private:
 386   // Used by SkipGCALot class.
 387   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 388 
 389   friend class GCLocker;
 390   friend class NoSafepointVerifier;
 391   friend class PauseNoSafepointVerifier;
 392 
 393   volatile void* _polling_page;                 // Thread local polling page
 394 
 395   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 396   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 397                                                 // the Java heap
 398   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 399 
 400   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 401 
 402   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 403 
 404   int   _vm_operation_started_count;            // VM_Operation support
 405   int   _vm_operation_completed_count;          // VM_Operation support
 406 
 407   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 408                                                 // is waiting to lock
 409   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 410 
 411   // ObjectMonitor on which this thread called Object.wait()
 412   ObjectMonitor* _current_waiting_monitor;
 413 
 414   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 415  public:
 416   ObjectMonitor* omFreeList;
 417   int omFreeCount;                              // length of omFreeList
 418   int omFreeProvision;                          // reload chunk size
 419   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 420   int omInUseCount;                             // length of omInUseList
 421 
 422 #ifdef ASSERT
 423  private:
 424   volatile uint64_t _visited_for_critical_count;
 425 
 426  public:
 427   void set_visited_for_critical_count(uint64_t safepoint_id) {
 428     assert(_visited_for_critical_count == 0, "Must be reset before set");
 429     assert((safepoint_id & 0x1) == 1, "Must be odd");
 430     _visited_for_critical_count = safepoint_id;
 431   }
 432   void reset_visited_for_critical_count(uint64_t safepoint_id) {
 433     assert(_visited_for_critical_count == safepoint_id, "Was not visited");
 434     _visited_for_critical_count = 0;
 435   }
 436   bool was_visited_for_critical_count(uint64_t safepoint_id) const {
 437     return _visited_for_critical_count == safepoint_id;
 438   }
 439 #endif
 440 
 441  public:
 442   enum {
 443     is_definitely_current_thread = true
 444   };
 445 
 446   // Constructor
 447   Thread();
 448   virtual ~Thread() = 0;        // Thread is abstract.
 449 
 450   // Manage Thread::current()
 451   void initialize_thread_current();
 452   static void clear_thread_current(); // TLS cleanup needed before threads terminate
 453 
 454  protected:
 455   // To be implemented by children.
 456   virtual void run() = 0;
 457   virtual void pre_run() = 0;
 458   virtual void post_run() = 0;  // Note: Thread must not be deleted prior to calling this!
 459 
 460 #ifdef ASSERT
 461   enum RunState {
 462     PRE_CALL_RUN,
 463     CALL_RUN,
 464     PRE_RUN,
 465     RUN,
 466     POST_RUN
 467     // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
 468   };
 469   RunState _run_state;  // for lifecycle checks
 470 #endif
 471 
 472 
 473  public:
 474   // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
 475   void call_run();
 476 
 477   // Testers
 478   virtual bool is_VM_thread()       const            { return false; }
 479   virtual bool is_Java_thread()     const            { return false; }
 480   virtual bool is_Compiler_thread() const            { return false; }
 481   virtual bool is_Code_cache_sweeper_thread() const  { return false; }
 482   virtual bool is_hidden_from_external_view() const  { return false; }
 483   virtual bool is_jvmti_agent_thread() const         { return false; }
 484   // True iff the thread can perform GC operations at a safepoint.
 485   // Generally will be true only of VM thread and parallel GC WorkGang
 486   // threads.
 487   virtual bool is_GC_task_thread() const             { return false; }
 488   virtual bool is_Watcher_thread() const             { return false; }
 489   virtual bool is_ConcurrentGC_thread() const        { return false; }
 490   virtual bool is_Named_thread() const               { return false; }
 491   virtual bool is_Worker_thread() const              { return false; }
 492 
 493   // Can this thread make Java upcalls
 494   virtual bool can_call_java() const                 { return false; }
 495 
 496   // Is this a JavaThread that is on the VM's current ThreadsList?
 497   // If so it must participate in the safepoint protocol.
 498   virtual bool is_active_Java_thread() const         { return false; }
 499 
 500   // Casts
 501   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 502 
 503   virtual char* name() const { return (char*)"Unknown thread"; }
 504 
 505   // Returns the current thread (ASSERTS if NULL)
 506   static inline Thread* current();
 507   // Returns the current thread, or NULL if not attached
 508   static inline Thread* current_or_null();
 509   // Returns the current thread, or NULL if not attached, and is
 510   // safe for use from signal-handlers
 511   static inline Thread* current_or_null_safe();
 512 
 513   // Common thread operations
 514 #ifdef ASSERT
 515   static void check_for_dangling_thread_pointer(Thread *thread);
 516 #endif
 517   static void set_priority(Thread* thread, ThreadPriority priority);
 518   static ThreadPriority get_priority(const Thread* const thread);
 519   static void start(Thread* thread);
 520   static void interrupt(Thread* thr);
 521   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 522 
 523   void set_native_thread_name(const char *name) {
 524     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 525     os::set_native_thread_name(name);
 526   }
 527 
 528   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 529   Monitor* SR_lock() const                       { return _SR_lock; }
 530 
 531   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 532 
 533   inline void set_suspend_flag(SuspendFlags f);
 534   inline void clear_suspend_flag(SuspendFlags f);
 535 
 536   inline void set_has_async_exception();
 537   inline void clear_has_async_exception();
 538 
 539   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 540 
 541   inline void set_critical_native_unlock();
 542   inline void clear_critical_native_unlock();
 543 
 544   inline void set_trace_flag();
 545   inline void clear_trace_flag();
 546 
 547   // Support for Unhandled Oop detection
 548   // Add the field for both, fastdebug and debug, builds to keep
 549   // Thread's fields layout the same.
 550   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 551 #ifdef CHECK_UNHANDLED_OOPS
 552  private:
 553   UnhandledOops* _unhandled_oops;
 554 #elif defined(ASSERT)
 555  private:
 556   void* _unhandled_oops;
 557 #endif
 558 #ifdef CHECK_UNHANDLED_OOPS
 559  public:
 560   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 561   // Mark oop safe for gc.  It may be stack allocated but won't move.
 562   void allow_unhandled_oop(oop *op) {
 563     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 564   }
 565   // Clear oops at safepoint so crashes point to unhandled oop violator
 566   void clear_unhandled_oops() {
 567     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 568   }
 569 #endif // CHECK_UNHANDLED_OOPS
 570 
 571  public:
 572 #ifndef PRODUCT
 573   bool skip_gcalot()           { return _skip_gcalot; }
 574   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 575 #endif
 576 
 577   // Installs a pending exception to be inserted later
 578   static void send_async_exception(oop thread_oop, oop java_throwable);
 579 
 580   // Resource area
 581   ResourceArea* resource_area() const            { return _resource_area; }
 582   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 583 
 584   OSThread* osthread() const                     { return _osthread;   }
 585   void set_osthread(OSThread* thread)            { _osthread = thread; }
 586 
 587   // JNI handle support
 588   JNIHandleBlock* active_handles() const         { return _active_handles; }
 589   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 590   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 591   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 592 
 593   // Internal handle support
 594   HandleArea* handle_area() const                { return _handle_area; }
 595   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 596 
 597   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 598   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 599 
 600   // Thread-Local Allocation Buffer (TLAB) support
 601   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 602   void initialize_tlab() {
 603     if (UseTLAB) {
 604       tlab().initialize();
 605     }
 606   }
 607 
 608   jlong allocated_bytes()               { return _allocated_bytes; }
 609   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 610   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 611   inline jlong cooked_allocated_bytes();
 612 
 613   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 614 
 615   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 616 
 617   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 618 
 619   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 620 
 621   // VM operation support
 622   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 623   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 624   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 625 
 626   // For tracking the heavyweight monitor the thread is pending on.
 627   ObjectMonitor* current_pending_monitor() {
 628     return _current_pending_monitor;
 629   }
 630   void set_current_pending_monitor(ObjectMonitor* monitor) {
 631     _current_pending_monitor = monitor;
 632   }
 633   void set_current_pending_monitor_is_from_java(bool from_java) {
 634     _current_pending_monitor_is_from_java = from_java;
 635   }
 636   bool current_pending_monitor_is_from_java() {
 637     return _current_pending_monitor_is_from_java;
 638   }
 639 
 640   // For tracking the ObjectMonitor on which this thread called Object.wait()
 641   ObjectMonitor* current_waiting_monitor() {
 642     return _current_waiting_monitor;
 643   }
 644   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 645     _current_waiting_monitor = monitor;
 646   }
 647 
 648   // GC support
 649   // Apply "f->do_oop" to all root oops in "this".
 650   //   Used by JavaThread::oops_do.
 651   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 652   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 653 
 654   // Handles the parallel case for claim_threads_do.
 655  private:
 656   bool claim_par_threads_do(uintx claim_token);
 657  public:
 658   // Requires that "claim_token" is that of the current iteration.
 659   // If "is_par" is false, sets the token of "this" to
 660   // "claim_token", and returns "true".  If "is_par" is true,
 661   // uses an atomic instruction to set the current thread's token to
 662   // "claim_token", if it is not already.  Returns "true" iff the
 663   // calling thread does the update, this indicates that the calling thread
 664   // has claimed the thread in the current iteration.
 665   bool claim_threads_do(bool is_par, uintx claim_token) {
 666     if (!is_par) {
 667       _threads_do_token = claim_token;
 668       return true;
 669     } else {
 670       return claim_par_threads_do(claim_token);
 671     }
 672   }
 673 
 674   uintx threads_do_token() const { return _threads_do_token; }
 675 
 676   // jvmtiRedefineClasses support
 677   void metadata_handles_do(void f(Metadata*));
 678 
 679   // Used by fast lock support
 680   virtual bool is_lock_owned(address adr) const;
 681 
 682   // Check if address is in the stack of the thread (not just for locks).
 683   // Warning: the method can only be used on the running thread
 684   bool is_in_stack(address adr) const;
 685   // Check if address is in the usable part of the stack (excludes protected
 686   // guard pages)
 687   bool is_in_usable_stack(address adr) const;
 688 
 689   // Sets this thread as starting thread. Returns failure if thread
 690   // creation fails due to lack of memory, too many threads etc.
 691   bool set_as_starting_thread();
 692 
 693 protected:
 694   // OS data associated with the thread
 695   OSThread* _osthread;  // Platform-specific thread information
 696 
 697   // Thread local resource area for temporary allocation within the VM
 698   ResourceArea* _resource_area;
 699 
 700   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 701 
 702   // Thread local handle area for allocation of handles within the VM
 703   HandleArea* _handle_area;
 704   GrowableArray<Metadata*>* _metadata_handles;
 705 
 706   // Support for stack overflow handling, get_thread, etc.
 707   address          _stack_base;
 708   size_t           _stack_size;
 709   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 710   int              _lgrp_id;
 711 
 712   volatile void** polling_page_addr() { return &_polling_page; }
 713 
 714  public:
 715   // Stack overflow support
 716   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 717   void    set_stack_base(address base) { _stack_base = base; }
 718   size_t  stack_size() const           { return _stack_size; }
 719   void    set_stack_size(size_t size)  { _stack_size = size; }
 720   address stack_end()  const           { return stack_base() - stack_size(); }
 721   void    record_stack_base_and_size();
 722   void    register_thread_stack_with_NMT() NOT_NMT_RETURN;
 723 
 724   bool    on_local_stack(address adr) const {
 725     // QQQ this has knowledge of direction, ought to be a stack method
 726     return (_stack_base >= adr && adr >= stack_end());
 727   }
 728 
 729   uintptr_t self_raw_id()                    { return _self_raw_id; }
 730   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 731 
 732   int     lgrp_id() const        { return _lgrp_id; }
 733   void    set_lgrp_id(int value) { _lgrp_id = value; }
 734 
 735   // Printing
 736   void print_on(outputStream* st, bool print_extended_info) const;
 737   virtual void print_on(outputStream* st) const { print_on(st, false); }
 738   void print() const;
 739   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 740   void print_value_on(outputStream* st) const;
 741 
 742   // Debug-only code
 743 #ifdef ASSERT
 744  private:
 745   // Deadlock detection support for Mutex locks. List of locks own by thread.
 746   Monitor* _owned_locks;
 747   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 748   // thus the friendship
 749   friend class Mutex;
 750   friend class Monitor;
 751 
 752  public:
 753   void print_owned_locks_on(outputStream* st) const;
 754   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 755   Monitor* owned_locks() const                   { return _owned_locks;          }
 756   bool owns_locks() const                        { return owned_locks() != NULL; }
 757   bool owns_locks_but_compiled_lock() const;
 758 
 759   // Deadlock detection
 760   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 761   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 762 #endif // ASSERT
 763 
 764   // These functions check conditions on a JavaThread before possibly going to a safepoint,
 765   // including NoSafepointVerifier.
 766   void check_for_valid_safepoint_state(bool potential_vm_operation) NOT_DEBUG_RETURN;
 767   void check_possible_safepoint() NOT_DEBUG_RETURN;
 768 
 769  private:
 770   volatile int _jvmti_env_iteration_count;
 771 
 772  public:
 773   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 774   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 775   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 776 
 777   // Code generation
 778   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 779   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 780   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 781 
 782   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 783   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 784 
 785   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 786 
 787   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 788   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 789   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 790   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 791 
 792   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 793 
 794   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 795 
 796  public:
 797   volatile intptr_t _Stalled;
 798   volatile int _TypeTag;
 799   ParkEvent * _ParkEvent;                     // for synchronized()
 800   ParkEvent * _SleepEvent;                    // for Thread.sleep
 801   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 802   int NativeSyncRecursion;                    // diagnostic
 803 
 804   volatile int _OnTrap;                       // Resume-at IP delta
 805   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 806   jint _hashStateX;                           // thread-specific hashCode generator state
 807   jint _hashStateY;
 808   jint _hashStateZ;
 809 
 810   // Low-level leaf-lock primitives used to implement synchronization
 811   // and native monitor-mutex infrastructure.
 812   // Not for general synchronization use.
 813   static void SpinAcquire(volatile int * Lock, const char * Name);
 814   static void SpinRelease(volatile int * Lock);
 815   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 816   static void muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev);
 817   static void muxRelease(volatile intptr_t * Lock);
 818 };
 819 
 820 // Inline implementation of Thread::current()
 821 inline Thread* Thread::current() {
 822   Thread* current = current_or_null();
 823   assert(current != NULL, "Thread::current() called on detached thread");
 824   return current;
 825 }
 826 
 827 inline Thread* Thread::current_or_null() {
 828 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 829   return _thr_current;
 830 #else
 831   if (ThreadLocalStorage::is_initialized()) {
 832     return ThreadLocalStorage::thread();
 833   }
 834   return NULL;
 835 #endif
 836 }
 837 
 838 inline Thread* Thread::current_or_null_safe() {
 839   if (ThreadLocalStorage::is_initialized()) {
 840     return ThreadLocalStorage::thread();
 841   }
 842   return NULL;
 843 }
 844 
 845 class NonJavaThread: public Thread {
 846   friend class VMStructs;
 847 
 848   NonJavaThread* volatile _next;
 849 
 850   class List;
 851   static List _the_list;
 852 
 853   void add_to_the_list();
 854   void remove_from_the_list();
 855 
 856  protected:
 857   virtual void pre_run();
 858   virtual void post_run();
 859 
 860  public:
 861   NonJavaThread();
 862   ~NonJavaThread();
 863 
 864   class Iterator;
 865 };
 866 
 867 // Provides iteration over the list of NonJavaThreads.
 868 // List addition occurs in pre_run(), and removal occurs in post_run(),
 869 // so that only live fully-initialized threads can be found in the list.
 870 // Threads created after an iterator is constructed will not be visited
 871 // by the iterator. The scope of an iterator is a critical section; there
 872 // must be no safepoint checks in that scope.
 873 class NonJavaThread::Iterator : public StackObj {
 874   uint _protect_enter;
 875   NonJavaThread* _current;
 876 
 877   // Noncopyable.
 878   Iterator(const Iterator&);
 879   Iterator& operator=(const Iterator&);
 880 
 881 public:
 882   Iterator();
 883   ~Iterator();
 884 
 885   bool end() const { return _current == NULL; }
 886   NonJavaThread* current() const { return _current; }
 887   void step();
 888 };
 889 
 890 // Name support for threads.  non-JavaThread subclasses with multiple
 891 // uniquely named instances should derive from this.
 892 class NamedThread: public NonJavaThread {
 893   friend class VMStructs;
 894   enum {
 895     max_name_len = 64
 896   };
 897  private:
 898   char* _name;
 899   // log JavaThread being processed by oops_do
 900   JavaThread* _processed_thread;
 901   uint _gc_id; // The current GC id when a thread takes part in GC
 902 
 903  public:
 904   NamedThread();
 905   ~NamedThread();
 906   // May only be called once per thread.
 907   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 908   virtual bool is_Named_thread() const { return true; }
 909   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 910   JavaThread *processed_thread() { return _processed_thread; }
 911   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 912   virtual void print_on(outputStream* st) const;
 913 
 914   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 915   uint gc_id() { return _gc_id; }
 916 };
 917 
 918 // Worker threads are named and have an id of an assigned work.
 919 class WorkerThread: public NamedThread {
 920  private:
 921   uint _id;
 922  public:
 923   WorkerThread() : _id(0)               { }
 924   virtual bool is_Worker_thread() const { return true; }
 925 
 926   virtual WorkerThread* as_Worker_thread() const {
 927     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 928     return (WorkerThread*) this;
 929   }
 930 
 931   void set_id(uint work_id)             { _id = work_id; }
 932   uint id() const                       { return _id; }
 933 };
 934 
 935 // A single WatcherThread is used for simulating timer interrupts.
 936 class WatcherThread: public NonJavaThread {
 937   friend class VMStructs;
 938  protected:
 939   virtual void run();
 940 
 941  private:
 942   static WatcherThread* _watcher_thread;
 943 
 944   static bool _startable;
 945   // volatile due to at least one lock-free read
 946   volatile static bool _should_terminate;
 947  public:
 948   enum SomeConstants {
 949     delay_interval = 10                          // interrupt delay in milliseconds
 950   };
 951 
 952   // Constructor
 953   WatcherThread();
 954 
 955   // No destruction allowed
 956   ~WatcherThread() {
 957     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 958   }
 959 
 960   // Tester
 961   bool is_Watcher_thread() const                 { return true; }
 962 
 963   // Printing
 964   char* name() const { return (char*)"VM Periodic Task Thread"; }
 965   void print_on(outputStream* st) const;
 966   void unpark();
 967 
 968   // Returns the single instance of WatcherThread
 969   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 970 
 971   // Create and start the single instance of WatcherThread, or stop it on shutdown
 972   static void start();
 973   static void stop();
 974   // Only allow start once the VM is sufficiently initialized
 975   // Otherwise the first task to enroll will trigger the start
 976   static void make_startable();
 977  private:
 978   int sleep() const;
 979 };
 980 
 981 
 982 class CompilerThread;
 983 
 984 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 985 
 986 class JavaThread: public Thread {
 987   friend class VMStructs;
 988   friend class JVMCIVMStructs;
 989   friend class WhiteBox;
 990   friend class Continuation;
 991  private:
 992   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
 993   oop            _threadObj;                     // The Java level thread object
 994 
 995 #ifdef ASSERT
 996  private:
 997   int _java_call_counter;
 998 
 999  public:
1000   int  java_call_counter()                       { return _java_call_counter; }
1001   void inc_java_call_counter()                   { _java_call_counter++; }
1002   void dec_java_call_counter() {
1003     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
1004     _java_call_counter--;
1005   }
1006  private:  // restore original namespace restriction
1007 #endif  // ifdef ASSERT
1008 
1009 #ifndef PRODUCT
1010  public:
1011   enum {
1012     jump_ring_buffer_size = 16
1013   };
1014  private:  // restore original namespace restriction
1015 #endif
1016 
1017   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
1018 
1019   ThreadFunction _entry_point;
1020 
1021   JNIEnv        _jni_environment;
1022 
1023   // Deopt support
1024   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
1025 
1026   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
1027                                                  // transition out of native
1028   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
1029   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
1030   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
1031   // Because deoptimization is lazy we must save jvmti requests to set locals
1032   // in compiled frames until we deoptimize and we have an interpreter frame.
1033   // This holds the pointer to array (yeah like there might be more than one) of
1034   // description of compiled vframes that have locals that need to be updated.
1035   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
1036   GrowableArray<WeakHandle<vm_nmethod_keepalive_data> >* _keepalive_cleanup;
1037 
1038   // Handshake value for fixing 6243940. We need a place for the i2c
1039   // adapter to store the callee Method*. This value is NEVER live
1040   // across a gc point so it does NOT have to be gc'd
1041   // The handshake is open ended since we can't be certain that it will
1042   // be NULLed. This is because we rarely ever see the race and end up
1043   // in handle_wrong_method which is the backend of the handshake. See
1044   // code in i2c adapters and handle_wrong_method.
1045 
1046   Method*       _callee_target;
1047 
1048   // Used to pass back results to the interpreter or generated code running Java code.
1049   oop           _vm_result;    // oop result is GC-preserved
1050   Metadata*     _vm_result_2;  // non-oop result
1051 
1052   // See ReduceInitialCardMarks: this holds the precise space interval of
1053   // the most recent slow path allocation for which compiled code has
1054   // elided card-marks for performance along the fast-path.
1055   MemRegion     _deferred_card_mark;
1056 
1057   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
1058                                                  // allocated during deoptimization
1059                                                  // and by JNI_MonitorEnter/Exit
1060 
1061   // Async. requests support
1062   enum AsyncRequests {
1063     _no_async_condition = 0,
1064     _async_exception,
1065     _async_unsafe_access_error
1066   };
1067   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1068   oop           _pending_async_exception;
1069 
1070   // Safepoint support
1071  public:                                         // Expose _thread_state for SafeFetchInt()
1072   volatile JavaThreadState _thread_state;
1073  private:
1074   ThreadSafepointState* _safepoint_state;        // Holds information about a thread during a safepoint
1075   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
1076 
1077   // JavaThread termination support
1078   enum TerminatedTypes {
1079     _not_terminated = 0xDEAD - 2,
1080     _thread_exiting,                             // JavaThread::exit() has been called for this thread
1081     _thread_terminated,                          // JavaThread is removed from thread list
1082     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
1083                                                  // only VM_Exit can set _vm_exited
1084   };
1085 
1086   // In general a JavaThread's _terminated field transitions as follows:
1087   //
1088   //   _not_terminated => _thread_exiting => _thread_terminated
1089   //
1090   // _vm_exited is a special value to cover the case of a JavaThread
1091   // executing native code after the VM itself is terminated.
1092   volatile TerminatedTypes _terminated;
1093   // suspend/resume support
1094   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1095   jint                  _in_deopt_handler;       // count of deoptimization
1096                                                  // handlers thread is in
1097   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1098   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1099                                                          // never locked) when throwing an exception. Used by interpreter only.
1100 
1101   // JNI attach states:
1102   enum JNIAttachStates {
1103     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1104     _attaching_via_jni,          // thread is attaching via JNI
1105     _attached_via_jni            // thread has attached via JNI
1106   };
1107 
1108   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1109   // A native thread that is attaching via JNI starts with a value
1110   // of _attaching_via_jni and transitions to _attached_via_jni.
1111   volatile JNIAttachStates _jni_attach_state;
1112 
1113  public:
1114   DEBUG_ONLY(oopDesc* _continuation;)
1115 
1116   // State of the stack guard pages for this thread.
1117   enum StackGuardState {
1118     stack_guard_unused,         // not needed
1119     stack_guard_reserved_disabled,
1120     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1121     stack_guard_enabled         // enabled
1122   };
1123 
1124  private:
1125 
1126 #if INCLUDE_JVMCI
1127   // The _pending_* fields below are used to communicate extra information
1128   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1129 
1130   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1131   int       _pending_deoptimization;
1132 
1133   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1134   // before the monitor has been acquired.
1135   bool      _pending_monitorenter;
1136 
1137   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1138   bool      _pending_transfer_to_interpreter;
1139 
1140   // True if in a runtime call from compiled code that will deoptimize
1141   // and re-execute a failed heap allocation in the interpreter.
1142   bool      _in_retryable_allocation;
1143 
1144   // An id of a speculation that JVMCI compiled code can use to further describe and
1145   // uniquely identify the  speculative optimization guarded by the uncommon trap
1146   jlong     _pending_failed_speculation;
1147 
1148   // These fields are mutually exclusive in terms of live ranges.
1149   union {
1150     // Communicates the pc at which the most recent implicit exception occurred
1151     // from the signal handler to a deoptimization stub.
1152     address   _implicit_exception_pc;
1153 
1154     // Communicates an alternative call target to an i2c stub from a JavaCall .
1155     address   _alternate_call_target;
1156   } _jvmci;
1157 
1158   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1159   jlong*    _jvmci_counters;
1160 
1161  public:
1162   static jlong* _jvmci_old_thread_counters;
1163   static void collect_counters(jlong* array, int length);
1164 
1165   bool resize_counters(int current_size, int new_size);
1166 
1167   static bool resize_all_jvmci_counters(int new_size);
1168 
1169  private:
1170 #endif // INCLUDE_JVMCI
1171 
1172   StackGuardState  _stack_guard_state;
1173 
1174   // Precompute the limit of the stack as used in stack overflow checks.
1175   // We load it from here to simplify the stack overflow check in assembly.
1176   address          _stack_overflow_limit;
1177   address          _reserved_stack_activation;
1178 
1179   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1180   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1181   // code)
1182   volatile oop     _exception_oop;               // Exception thrown in compiled code
1183   volatile address _exception_pc;                // PC where exception happened
1184   volatile address _exception_handler_pc;        // PC for handler of exception
1185   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1186 
1187  private:
1188   // support for JNI critical regions
1189   jint    _jni_active_critical;                  // count of entries into JNI critical region
1190 
1191   // Checked JNI: function name requires exception check
1192   char* _pending_jni_exception_check_fn;
1193 
1194   // For deadlock detection.
1195   int _depth_first_number;
1196 
1197   // JVMTI PopFrame support
1198   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1199   int _popframe_condition;
1200 
1201   // If reallocation of scalar replaced objects fails, we throw OOM
1202   // and during exception propagation, pop the top
1203   // _frames_to_pop_failed_realloc frames, the ones that reference
1204   // failed reallocations.
1205   int _frames_to_pop_failed_realloc;
1206 
1207   bool _cont_yield; // a continuation yield is in progress
1208   bool _cont_preempt;
1209   FrameInfo _cont_frame;
1210   int _cont_fastpath;
1211 
1212 #ifndef PRODUCT
1213   int _jmp_ring_index;
1214   struct {
1215     // We use intptr_t instead of address so debugger doesn't try and display strings
1216     intptr_t _target;
1217     intptr_t _instruction;
1218     const char*  _file;
1219     int _line;
1220   }   _jmp_ring[jump_ring_buffer_size];
1221 #endif // PRODUCT
1222 
1223   friend class VMThread;
1224   friend class ThreadWaitTransition;
1225   friend class VM_Exit;
1226 
1227   void initialize();                             // Initialized the instance variables
1228 
1229  public:
1230   // Constructor
1231   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1232   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1233   ~JavaThread();
1234 
1235 #ifdef ASSERT
1236   // verify this JavaThread hasn't be published in the Threads::list yet
1237   void verify_not_published();
1238 #endif // ASSERT
1239 
1240   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1241   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1242     _jni_environment.functions = functionTable;
1243   }
1244   struct JNINativeInterface_* get_jni_functions() {
1245     return (struct JNINativeInterface_ *)_jni_environment.functions;
1246   }
1247 
1248   // This function is called at thread creation to allow
1249   // platform specific thread variables to be initialized.
1250   void cache_global_variables();
1251 
1252   // Executes Shutdown.shutdown()
1253   void invoke_shutdown_hooks();
1254 
1255   // Cleanup on thread exit
1256   enum ExitType {
1257     normal_exit,
1258     jni_detach
1259   };
1260   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1261 
1262   void cleanup_failed_attach_current_thread(bool is_daemon);
1263 
1264   // Testers
1265   virtual bool is_Java_thread() const            { return true;  }
1266   virtual bool can_call_java() const             { return true; }
1267 
1268   virtual bool is_active_Java_thread() const {
1269     return on_thread_list() && !is_terminated();
1270   }
1271 
1272   // Thread oop. threadObj() can be NULL for initial JavaThread
1273   // (or for threads attached via JNI)
1274   oop threadObj() const                          { return _threadObj; }
1275   void set_threadObj(oop p)                      { _threadObj = p; }
1276 
1277   ThreadPriority java_priority() const;          // Read from threadObj()
1278 
1279   // Prepare thread and add to priority queue.  If a priority is
1280   // not specified, use the priority of the thread object. Threads_lock
1281   // must be held while this function is called.
1282   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1283 
1284   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1285   address saved_exception_pc()                   { return _saved_exception_pc; }
1286 
1287 
1288   ThreadFunction entry_point() const             { return _entry_point; }
1289 
1290   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1291   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1292 
1293   // Last frame anchor routines
1294 
1295   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1296 
1297   // last_Java_sp
1298   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1299   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1300 
1301   // last_Java_pc
1302 
1303   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1304 
1305   // Safepoint support
1306   inline JavaThreadState thread_state() const;
1307   inline void set_thread_state(JavaThreadState s);
1308   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
1309   inline ThreadSafepointState* safepoint_state() const;
1310   inline void set_safepoint_state(ThreadSafepointState* state);
1311   inline bool is_at_poll_safepoint();
1312 
1313   // JavaThread termination and lifecycle support:
1314   void smr_delete();
1315   bool on_thread_list() const { return _on_thread_list; }
1316   void set_on_thread_list() { _on_thread_list = true; }
1317 
1318   // thread has called JavaThread::exit() or is terminated
1319   bool is_exiting() const;
1320   // thread is terminated (no longer on the threads list); we compare
1321   // against the two non-terminated values so that a freed JavaThread
1322   // will also be considered terminated.
1323   bool check_is_terminated(TerminatedTypes l_terminated) const {
1324     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1325   }
1326   bool is_terminated() const;
1327   void set_terminated(TerminatedTypes t);
1328   // special for Threads::remove() which is static:
1329   void set_terminated_value();
1330   void block_if_vm_exited();
1331 
1332   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1333   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1334 
1335   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1336   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1337 
1338   inline void set_polling_page_release(void* poll_value);
1339   inline void set_polling_page(void* poll_value);
1340   inline volatile void* get_polling_page();
1341 
1342   // Continuation support
1343   bool cont_yield() { return _cont_yield; }
1344   void set_cont_yield(bool x) { _cont_yield = x; }
1345   bool cont_fastpath() { return _cont_fastpath != 0; }
1346   void set_cont_fastpath(bool x) { _cont_fastpath = (int)x; }
1347   bool cont_preempt() { return _cont_preempt; }
1348   void set_cont_preempt(bool x) { _cont_preempt = x; }
1349   FrameInfo* cont_frame() { return &_cont_frame; }
1350 
1351  private:
1352   // Support for thread handshake operations
1353   HandshakeState _handshake;
1354  public:
1355   void set_handshake_operation(HandshakeOperation* op) {
1356     _handshake.set_operation(this, op);
1357   }
1358 
1359   bool has_handshake() const {
1360     return _handshake.has_operation();
1361   }
1362 
1363   void handshake_process_by_self() {
1364     _handshake.process_by_self(this);
1365   }
1366 
1367   void handshake_process_by_vmthread() {
1368     _handshake.process_by_vmthread(this);
1369   }
1370 
1371   // Suspend/resume support for JavaThread
1372  private:
1373   inline void set_ext_suspended();
1374   inline void clear_ext_suspended();
1375 
1376  public:
1377   void java_suspend(); // higher-level suspension logic called by the public APIs
1378   void java_resume();  // higher-level resume logic called by the public APIs
1379   int  java_suspend_self(); // low-level self-suspension mechanics
1380 
1381  private:
1382   // mid-level wrapper around java_suspend_self to set up correct state and
1383   // check for a pending safepoint at the end
1384   void java_suspend_self_with_safepoint_check();
1385 
1386  public:
1387   void check_and_wait_while_suspended() {
1388     assert(JavaThread::current() == this, "sanity check");
1389 
1390     bool do_self_suspend;
1391     do {
1392       // were we externally suspended while we were waiting?
1393       do_self_suspend = handle_special_suspend_equivalent_condition();
1394       if (do_self_suspend) {
1395         // don't surprise the thread that suspended us by returning
1396         java_suspend_self();
1397         set_suspend_equivalent();
1398       }
1399     } while (do_self_suspend);
1400   }
1401   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1402   // Check for async exception in addition to safepoint and suspend request.
1403   static void check_special_condition_for_native_trans(JavaThread *thread);
1404 
1405   // Same as check_special_condition_for_native_trans but finishes the
1406   // transition into thread_in_Java mode so that it can potentially
1407   // block.
1408   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1409 
1410   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1411   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1412     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1413     // Warning: is_ext_suspend_completed() may temporarily drop the
1414     // SR_lock to allow the thread to reach a stable thread state if
1415     // it is currently in a transient thread state.
1416     return is_ext_suspend_completed(false /* !called_by_wait */,
1417                                     SuspendRetryDelay, bits);
1418   }
1419 
1420   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1421   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1422   // passed as the count and delay parameters. Experiments with specific
1423   // calls to wait_for_ext_suspend_completion() can be done by passing
1424   // other values in the code. Experiments with all calls can be done
1425   // via the appropriate -XX options.
1426   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1427 
1428   // test for suspend - most (all?) of these should go away
1429   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1430 
1431   inline void set_external_suspend();
1432   inline void clear_external_suspend();
1433 
1434   bool is_external_suspend() const {
1435     return (_suspend_flags & _external_suspend) != 0;
1436   }
1437   // Whenever a thread transitions from native to vm/java it must suspend
1438   // if external|deopt suspend is present.
1439   bool is_suspend_after_native() const {
1440     return (_suspend_flags & (_external_suspend JFR_ONLY(| _trace_flag))) != 0;
1441   }
1442 
1443   // external suspend request is completed
1444   bool is_ext_suspended() const {
1445     return (_suspend_flags & _ext_suspended) != 0;
1446   }
1447 
1448   bool is_external_suspend_with_lock() const {
1449     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1450     return is_external_suspend();
1451   }
1452 
1453   // Special method to handle a pending external suspend request
1454   // when a suspend equivalent condition lifts.
1455   bool handle_special_suspend_equivalent_condition() {
1456     assert(is_suspend_equivalent(),
1457            "should only be called in a suspend equivalence condition");
1458     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1459     bool ret = is_external_suspend();
1460     if (!ret) {
1461       // not about to self-suspend so clear suspend equivalence
1462       clear_suspend_equivalent();
1463     }
1464     // implied else:
1465     // We have a pending external suspend request so we leave the
1466     // suspend_equivalent flag set until java_suspend_self() sets
1467     // the ext_suspended flag and clears the suspend_equivalent
1468     // flag. This insures that wait_for_ext_suspend_completion()
1469     // will return consistent values.
1470     return ret;
1471   }
1472 
1473   // utility methods to see if we are doing some kind of suspension
1474   bool is_being_ext_suspended() const            {
1475     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1476     return is_ext_suspended() || is_external_suspend();
1477   }
1478 
1479   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1480 
1481   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1482   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1483 
1484   // Thread.stop support
1485   void send_thread_stop(oop throwable);
1486   AsyncRequests clear_special_runtime_exit_condition() {
1487     AsyncRequests x = _special_runtime_exit_condition;
1488     _special_runtime_exit_condition = _no_async_condition;
1489     return x;
1490   }
1491 
1492   bool is_cont_force_yield() { return cont_preempt(); }
1493   // Are any async conditions present?
1494   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1495 
1496   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1497 
1498   // these next two are also used for self-suspension and async exception support
1499   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1500 
1501   // Return true if JavaThread has an asynchronous condition or
1502   // if external suspension is requested.
1503   bool has_special_runtime_exit_condition() {
1504     // Because we don't use is_external_suspend_with_lock
1505     // it is possible that we won't see an asynchronous external suspend
1506     // request that has just gotten started, i.e., SR_lock grabbed but
1507     // _external_suspend field change either not made yet or not visible
1508     // yet. However, this is okay because the request is asynchronous and
1509     // we will see the new flag value the next time through. It's also
1510     // possible that the external suspend request is dropped after
1511     // we have checked is_external_suspend(), we will recheck its value
1512     // under SR_lock in java_suspend_self().
1513     return (_special_runtime_exit_condition != _no_async_condition) ||
1514             is_external_suspend() || is_trace_suspend() || is_cont_force_yield();
1515   }
1516 
1517   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1518 
1519   inline void set_pending_async_exception(oop e);
1520 
1521   // Fast-locking support
1522   bool is_lock_owned(address adr) const;
1523 
1524   // Accessors for vframe array top
1525   // The linked list of vframe arrays are sorted on sp. This means when we
1526   // unpack the head must contain the vframe array to unpack.
1527   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1528   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1529 
1530   // Side structure for deferring update of java frame locals until deopt occurs
1531   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1532   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1533 
1534   void set_keepalive_cleanup(GrowableArray<WeakHandle<vm_nmethod_keepalive_data> >* lst) { _keepalive_cleanup = lst; }
1535   GrowableArray<WeakHandle<vm_nmethod_keepalive_data> >* keepalive_cleanup() const { return _keepalive_cleanup; }
1536 
1537   // These only really exist to make debugging deopt problems simpler
1538 
1539   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1540   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1541 
1542   // The special resourceMark used during deoptimization
1543 
1544   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1545   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1546 
1547   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1548   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1549   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1550 
1551   void set_deopt_compiled_method(CompiledMethod* nm)  { _deopt_nmethod = nm; }
1552   CompiledMethod* deopt_compiled_method()        { return _deopt_nmethod; }
1553 
1554   Method*    callee_target() const               { return _callee_target; }
1555   void set_callee_target  (Method* x)          { _callee_target   = x; }
1556 
1557   // Oop results of vm runtime calls
1558   oop  vm_result() const                         { return _vm_result; }
1559   void set_vm_result  (oop x)                    { _vm_result   = x; }
1560 
1561   Metadata*    vm_result_2() const               { return _vm_result_2; }
1562   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1563 
1564   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1565   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1566 
1567 #if INCLUDE_JVMCI
1568   int  pending_deoptimization() const             { return _pending_deoptimization; }
1569   jlong pending_failed_speculation() const        { return _pending_failed_speculation; }
1570   bool has_pending_monitorenter() const           { return _pending_monitorenter; }
1571   void set_pending_monitorenter(bool b)           { _pending_monitorenter = b; }
1572   void set_pending_deoptimization(int reason)     { _pending_deoptimization = reason; }
1573   void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
1574   void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1575   void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1576   void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1577 
1578   virtual bool in_retryable_allocation() const    { return _in_retryable_allocation; }
1579   void set_in_retryable_allocation(bool b)        { _in_retryable_allocation = b; }
1580 #endif // INCLUDE_JVMCI
1581 
1582   // Exception handling for compiled methods
1583   oop      exception_oop() const                 { return _exception_oop; }
1584   address  exception_pc() const                  { return _exception_pc; }
1585   address  exception_handler_pc() const          { return _exception_handler_pc; }
1586   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1587 
1588   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1589   void set_exception_pc(address a)               { _exception_pc = a; }
1590   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1591   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1592 
1593   void clear_exception_oop_and_pc() {
1594     set_exception_oop(NULL);
1595     set_exception_pc(NULL);
1596   }
1597 
1598   // Stack overflow support
1599   //
1600   //  (small addresses)
1601   //
1602   //  --  <-- stack_end()                   ---
1603   //  |                                      |
1604   //  |  red pages                           |
1605   //  |                                      |
1606   //  --  <-- stack_red_zone_base()          |
1607   //  |                                      |
1608   //  |                                     guard
1609   //  |  yellow pages                       zone
1610   //  |                                      |
1611   //  |                                      |
1612   //  --  <-- stack_yellow_zone_base()       |
1613   //  |                                      |
1614   //  |                                      |
1615   //  |  reserved pages                      |
1616   //  |                                      |
1617   //  --  <-- stack_reserved_zone_base()    ---      ---
1618   //                                                 /|\  shadow     <--  stack_overflow_limit() (somewhere in here)
1619   //                                                  |   zone
1620   //                                                 \|/  size
1621   //  some untouched memory                          ---
1622   //
1623   //
1624   //  --
1625   //  |
1626   //  |  shadow zone
1627   //  |
1628   //  --
1629   //  x    frame n
1630   //  --
1631   //  x    frame n-1
1632   //  x
1633   //  --
1634   //  ...
1635   //
1636   //  --
1637   //  x    frame 0
1638   //  --  <-- stack_base()
1639   //
1640   //  (large addresses)
1641   //
1642 
1643  private:
1644   // These values are derived from flags StackRedPages, StackYellowPages,
1645   // StackReservedPages and StackShadowPages. The zone size is determined
1646   // ergonomically if page_size > 4K.
1647   static size_t _stack_red_zone_size;
1648   static size_t _stack_yellow_zone_size;
1649   static size_t _stack_reserved_zone_size;
1650   static size_t _stack_shadow_zone_size;
1651  public:
1652   inline size_t stack_available(address cur_sp);
1653 
1654   static size_t stack_red_zone_size() {
1655     assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1656     return _stack_red_zone_size;
1657   }
1658   static void set_stack_red_zone_size(size_t s) {
1659     assert(is_aligned(s, os::vm_page_size()),
1660            "We can not protect if the red zone size is not page aligned.");
1661     assert(_stack_red_zone_size == 0, "This should be called only once.");
1662     _stack_red_zone_size = s;
1663   }
1664   address stack_red_zone_base() {
1665     return (address)(stack_end() + stack_red_zone_size());
1666   }
1667   bool in_stack_red_zone(address a) {
1668     return a <= stack_red_zone_base() && a >= stack_end();
1669   }
1670 
1671   static size_t stack_yellow_zone_size() {
1672     assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1673     return _stack_yellow_zone_size;
1674   }
1675   static void set_stack_yellow_zone_size(size_t s) {
1676     assert(is_aligned(s, os::vm_page_size()),
1677            "We can not protect if the yellow zone size is not page aligned.");
1678     assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1679     _stack_yellow_zone_size = s;
1680   }
1681 
1682   static size_t stack_reserved_zone_size() {
1683     // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1684     return _stack_reserved_zone_size;
1685   }
1686   static void set_stack_reserved_zone_size(size_t s) {
1687     assert(is_aligned(s, os::vm_page_size()),
1688            "We can not protect if the reserved zone size is not page aligned.");
1689     assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1690     _stack_reserved_zone_size = s;
1691   }
1692   address stack_reserved_zone_base() {
1693     return (address)(stack_end() +
1694                      (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1695   }
1696   bool in_stack_reserved_zone(address a) {
1697     return (a <= stack_reserved_zone_base()) &&
1698            (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1699   }
1700 
1701   static size_t stack_yellow_reserved_zone_size() {
1702     return _stack_yellow_zone_size + _stack_reserved_zone_size;
1703   }
1704   bool in_stack_yellow_reserved_zone(address a) {
1705     return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1706   }
1707 
1708   // Size of red + yellow + reserved zones.
1709   static size_t stack_guard_zone_size() {
1710     return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1711   }
1712 
1713   static size_t stack_shadow_zone_size() {
1714     assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1715     return _stack_shadow_zone_size;
1716   }
1717   static void set_stack_shadow_zone_size(size_t s) {
1718     // The shadow area is not allocated or protected, so
1719     // it needs not be page aligned.
1720     // But the stack bang currently assumes that it is a
1721     // multiple of page size. This guarantees that the bang
1722     // loop touches all pages in the shadow zone.
1723     // This can be guaranteed differently, as well.  E.g., if
1724     // the page size is a multiple of 4K, banging in 4K steps
1725     // suffices to touch all pages. (Some pages are banged
1726     // several times, though.)
1727     assert(is_aligned(s, os::vm_page_size()),
1728            "Stack bang assumes multiple of page size.");
1729     assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1730     _stack_shadow_zone_size = s;
1731   }
1732 
1733   void create_stack_guard_pages();
1734   void remove_stack_guard_pages();
1735 
1736   void enable_stack_reserved_zone();
1737   void disable_stack_reserved_zone();
1738   void enable_stack_yellow_reserved_zone();
1739   void disable_stack_yellow_reserved_zone();
1740   void enable_stack_red_zone();
1741   void disable_stack_red_zone();
1742 
1743   inline bool stack_guard_zone_unused();
1744   inline bool stack_yellow_reserved_zone_disabled();
1745   inline bool stack_reserved_zone_disabled();
1746   inline bool stack_guards_enabled();
1747 
1748   address reserved_stack_activation() const { return _reserved_stack_activation; }
1749   void set_reserved_stack_activation(address addr) {
1750     assert(_reserved_stack_activation == stack_base()
1751             || _reserved_stack_activation == NULL
1752             || addr == stack_base(), "Must not be set twice");
1753     _reserved_stack_activation = addr;
1754   }
1755 
1756   // Attempt to reguard the stack after a stack overflow may have occurred.
1757   // Returns true if (a) guard pages are not needed on this thread, (b) the
1758   // pages are already guarded, or (c) the pages were successfully reguarded.
1759   // Returns false if there is not enough stack space to reguard the pages, in
1760   // which case the caller should unwind a frame and try again.  The argument
1761   // should be the caller's (approximate) sp.
1762   bool reguard_stack(address cur_sp);
1763   // Similar to above but see if current stackpoint is out of the guard area
1764   // and reguard if possible.
1765   bool reguard_stack(void);
1766 
1767   address stack_overflow_limit() { return _stack_overflow_limit; }
1768   void set_stack_overflow_limit() {
1769     _stack_overflow_limit =
1770       stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1771   }
1772 
1773   // Misc. accessors/mutators
1774   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1775   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1776   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1777 
1778 #ifndef PRODUCT
1779   void record_jump(address target, address instr, const char* file, int line);
1780 #endif // PRODUCT
1781 
1782   // For assembly stub generation
1783   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1784 #ifndef PRODUCT
1785   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index); }
1786   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring); }
1787 #endif // PRODUCT
1788   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1789   static ByteSize pending_jni_exception_check_fn_offset() {
1790     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1791   }
1792   static ByteSize last_Java_sp_offset() {
1793     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1794   }
1795   static ByteSize last_Java_pc_offset() {
1796     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1797   }
1798   static ByteSize frame_anchor_offset() {
1799     return byte_offset_of(JavaThread, _anchor);
1800   }
1801   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1802   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1803   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1804   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1805   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1806   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1807 #if INCLUDE_JVMCI
1808   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1809   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1810   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1811   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1812   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1813   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1814 #endif // INCLUDE_JVMCI
1815   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1816   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1817   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1818   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1819   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1820   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1821   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1822   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1823 
1824   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1825   static ByteSize should_post_on_exceptions_flag_offset() {
1826     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1827   }
1828   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
1829 
1830   DEBUG_ONLY(static ByteSize continuation_offset() { return byte_offset_of(JavaThread, _continuation); })
1831   static ByteSize cont_fastpath_offset()      { return byte_offset_of(JavaThread, _cont_fastpath); }
1832   static ByteSize cont_frame_offset()         { return byte_offset_of(JavaThread, _cont_frame); }
1833   static ByteSize cont_preempt_offset()       { return byte_offset_of(JavaThread, _cont_preempt); }
1834 
1835   // Returns the jni environment for this thread
1836   JNIEnv* jni_environment()                      { return &_jni_environment; }
1837 
1838   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1839     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1840     // Only return NULL if thread is off the thread list; starting to
1841     // exit should not return NULL.
1842     if (thread_from_jni_env->is_terminated()) {
1843       thread_from_jni_env->block_if_vm_exited();
1844       return NULL;
1845     } else {
1846       return thread_from_jni_env;
1847     }
1848   }
1849 
1850   // JNI critical regions. These can nest.
1851   bool in_critical()    { return _jni_active_critical > 0; }
1852   bool in_last_critical()  { return _jni_active_critical == 1; }
1853   inline void enter_critical();
1854   void exit_critical() {
1855     assert(Thread::current() == this, "this must be current thread");
1856     _jni_active_critical--;
1857     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1858   }
1859 
1860   // Checked JNI: is the programmer required to check for exceptions, if so specify
1861   // which function name. Returning to a Java frame should implicitly clear the
1862   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1863   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1864   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1865   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1866   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1867   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1868   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1869 
1870   // For deadlock detection
1871   int depth_first_number() { return _depth_first_number; }
1872   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1873 
1874  private:
1875   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1876 
1877  public:
1878   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1879   void add_monitor_chunk(MonitorChunk* chunk);
1880   void remove_monitor_chunk(MonitorChunk* chunk);
1881   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1882   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1883   void dec_in_deopt_handler() {
1884     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1885     if (_in_deopt_handler > 0) { // robustness
1886       _in_deopt_handler--;
1887     }
1888   }
1889 
1890  private:
1891   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1892 
1893  public:
1894 
1895   // Frame iteration; calls the function f for all frames on the stack
1896   void frames_do(void f(frame*, const RegisterMap*));
1897 
1898   // Memory operations
1899   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1900 
1901   // Sweeper operations
1902   virtual void nmethods_do(CodeBlobClosure* cf);
1903 
1904   // RedefineClasses Support
1905   void metadata_do(MetadataClosure* f);
1906 
1907   // Debug method asserting thread states are correct during a handshake operation.
1908   DEBUG_ONLY(void verify_states_for_handshake();)
1909 
1910   // Misc. operations
1911   char* name() const { return (char*)get_thread_name(); }
1912   void print_on(outputStream* st, bool print_extended_info) const;
1913   void print_on(outputStream* st) const { print_on(st, false); }
1914   void print() const;
1915   void print_value();
1916   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1917   void print_thread_state() const                      PRODUCT_RETURN;
1918   DEBUG_ONLY(const char* thread_state_name() const;)
1919   void print_on_error(outputStream* st, char* buf, int buflen) const;
1920   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1921   void verify();
1922   const char* get_thread_name() const;
1923  protected:
1924   // factor out low-level mechanics for use in both normal and error cases
1925   virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1926  public:
1927   const char* get_threadgroup_name() const;
1928   const char* get_parent_name() const;
1929 
1930   // Accessing frames
1931   frame last_frame() {
1932     _anchor.make_walkable(this);
1933     return pd_last_frame();
1934   }
1935   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1936 
1937   oop last_continuation();
1938   
1939   // Returns method at 'depth' java or native frames down the stack
1940   // Used for security checks
1941   Klass* security_get_caller_class(int depth);
1942 
1943   // Print stack trace in external format
1944   void print_stack_on(outputStream* st);
1945   void print_stack() { print_stack_on(tty); }
1946 
1947   // Print stack traces in various internal formats
1948   void trace_stack()                             PRODUCT_RETURN;
1949   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1950   void trace_frames()                            PRODUCT_RETURN;
1951   void trace_oops()                              PRODUCT_RETURN;
1952 
1953   // Print an annotated view of the stack frames
1954   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1955   void validate_frame_layout() {
1956     print_frame_layout(0, true);
1957   }
1958 
1959   // Returns the number of stack frames on the stack
1960   int depth() const;
1961 
1962   // Function for testing deoptimization
1963   void deoptimize();
1964   void make_zombies();
1965 
1966   void deoptimized_wrt_marked_nmethods();
1967 
1968  public:
1969   // Returns the running thread as a JavaThread
1970   static inline JavaThread* current();
1971 
1972   // Returns the active Java thread.  Do not use this if you know you are calling
1973   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1974   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1975   // operation.  You may not want that either.
1976   static JavaThread* active();
1977 
1978   inline CompilerThread* as_CompilerThread();
1979 
1980  protected:
1981   virtual void pre_run();
1982   virtual void run();
1983   void thread_main_inner();
1984   virtual void post_run();
1985 
1986 
1987  private:
1988   GrowableArray<oop>* _array_for_gc;
1989  public:
1990 
1991   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1992 
1993  public:
1994   // Thread local information maintained by JVMTI.
1995   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1996   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1997   // getter is used to get this JavaThread's JvmtiThreadState if it has
1998   // one which means NULL can be returned. JvmtiThreadState::state_for()
1999   // is used to get the specified JavaThread's JvmtiThreadState if it has
2000   // one or it allocates a new JvmtiThreadState for the JavaThread and
2001   // returns it. JvmtiThreadState::state_for() will return NULL only if
2002   // the specified JavaThread is exiting.
2003   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
2004   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
2005 
2006   // JVMTI PopFrame support
2007   // Setting and clearing popframe_condition
2008   // All of these enumerated values are bits. popframe_pending
2009   // indicates that a PopFrame() has been requested and not yet been
2010   // completed. popframe_processing indicates that that PopFrame() is in
2011   // the process of being completed. popframe_force_deopt_reexecution_bit
2012   // indicates that special handling is required when returning to a
2013   // deoptimized caller.
2014   enum PopCondition {
2015     popframe_inactive                      = 0x00,
2016     popframe_pending_bit                   = 0x01,
2017     popframe_processing_bit                = 0x02,
2018     popframe_force_deopt_reexecution_bit   = 0x04
2019   };
2020   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
2021   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
2022   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
2023   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
2024   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
2025   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
2026   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
2027   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
2028 #ifdef CC_INTERP
2029   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
2030   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
2031   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
2032   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
2033   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
2034 #endif
2035 
2036   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
2037   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
2038   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
2039 
2040  private:
2041   // Saved incoming arguments to popped frame.
2042   // Used only when popped interpreted frame returns to deoptimized frame.
2043   void*    _popframe_preserved_args;
2044   int      _popframe_preserved_args_size;
2045 
2046  public:
2047   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
2048   void* popframe_preserved_args();
2049   ByteSize popframe_preserved_args_size();
2050   WordSize popframe_preserved_args_size_in_words();
2051   void  popframe_free_preserved_args();
2052 
2053 
2054  private:
2055   JvmtiThreadState *_jvmti_thread_state;
2056 
2057   // Used by the interpreter in fullspeed mode for frame pop, method
2058   // entry, method exit and single stepping support. This field is
2059   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
2060   // It can be set to zero asynchronously (i.e., without a VM operation
2061   // or a lock) so we have to be very careful.
2062   int               _interp_only_mode;
2063 
2064  public:
2065   // used by the interpreter for fullspeed debugging support (see above)
2066   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2067   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
2068   int get_interp_only_mode()                { return _interp_only_mode; }
2069   void increment_interp_only_mode()         { ++_interp_only_mode; }
2070   void decrement_interp_only_mode()         { --_interp_only_mode; }
2071 
2072   // support for cached flag that indicates whether exceptions need to be posted for this thread
2073   // if this is false, we can avoid deoptimizing when events are thrown
2074   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2075  private:
2076   int    _should_post_on_exceptions_flag;
2077 
2078  public:
2079   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
2080   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
2081 
2082  private:
2083   ThreadStatistics *_thread_stat;
2084 
2085  public:
2086   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
2087 
2088   // Return a blocker object for which this thread is blocked parking.
2089   oop current_park_blocker();
2090 
2091  private:
2092   static size_t _stack_size_at_create;
2093 
2094  public:
2095   static inline size_t stack_size_at_create(void) {
2096     return _stack_size_at_create;
2097   }
2098   static inline void set_stack_size_at_create(size_t value) {
2099     _stack_size_at_create = value;
2100   }
2101 
2102   // Machine dependent stuff
2103 #include OS_CPU_HEADER(thread)
2104 
2105  public:
2106   void set_blocked_on_compilation(bool value) {
2107     _blocked_on_compilation = value;
2108   }
2109 
2110   bool blocked_on_compilation() {
2111     return _blocked_on_compilation;
2112   }
2113  protected:
2114   bool         _blocked_on_compilation;
2115 
2116 
2117   // JSR166 per-thread parker
2118  private:
2119   Parker*    _parker;
2120  public:
2121   Parker*     parker() { return _parker; }
2122 
2123   // Biased locking support
2124  private:
2125   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2126  public:
2127   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2128   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2129 
2130   // clearing/querying jni attach status
2131   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2132   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2133   inline void set_done_attaching_via_jni();
2134 
2135   // Stack dump assistance:
2136   // Track the class we want to initialize but for which we have to wait
2137   // on its init_lock() because it is already being initialized.
2138   void set_class_to_be_initialized(InstanceKlass* k);
2139   InstanceKlass* class_to_be_initialized() const;
2140 
2141 private:
2142   InstanceKlass* _class_to_be_initialized;
2143 
2144 };
2145 
2146 // Inline implementation of JavaThread::current
2147 inline JavaThread* JavaThread::current() {
2148   Thread* thread = Thread::current();
2149   assert(thread->is_Java_thread(), "just checking");
2150   return (JavaThread*)thread;
2151 }
2152 
2153 inline CompilerThread* JavaThread::as_CompilerThread() {
2154   assert(is_Compiler_thread(), "just checking");
2155   return (CompilerThread*)this;
2156 }
2157 
2158 // Dedicated thread to sweep the code cache
2159 class CodeCacheSweeperThread : public JavaThread {
2160   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2161  public:
2162   CodeCacheSweeperThread();
2163   // Track the nmethod currently being scanned by the sweeper
2164   void set_scanned_compiled_method(CompiledMethod* cm) {
2165     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2166     _scanned_compiled_method = cm;
2167   }
2168 
2169   // Hide sweeper thread from external view.
2170   bool is_hidden_from_external_view() const { return true; }
2171 
2172   bool is_Code_cache_sweeper_thread() const { return true; }
2173 
2174   // Prevent GC from unloading _scanned_compiled_method
2175   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2176   void nmethods_do(CodeBlobClosure* cf);
2177 };
2178 
2179 // A thread used for Compilation.
2180 class CompilerThread : public JavaThread {
2181   friend class VMStructs;
2182  private:
2183   CompilerCounters* _counters;
2184 
2185   ciEnv*                _env;
2186   CompileLog*           _log;
2187   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2188   CompileQueue*         _queue;
2189   BufferBlob*           _buffer_blob;
2190 
2191   AbstractCompiler*     _compiler;
2192   TimeStamp             _idle_time;
2193 
2194  public:
2195 
2196   static CompilerThread* current();
2197 
2198   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2199   ~CompilerThread();
2200 
2201   bool is_Compiler_thread() const                { return true; }
2202 
2203   virtual bool can_call_java() const;
2204 
2205   // Hide native compiler threads from external view.
2206   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2207 
2208   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2209   AbstractCompiler* compiler() const             { return _compiler; }
2210 
2211   CompileQueue* queue()        const             { return _queue; }
2212   CompilerCounters* counters() const             { return _counters; }
2213 
2214   // Get/set the thread's compilation environment.
2215   ciEnv*        env()                            { return _env; }
2216   void          set_env(ciEnv* env)              { _env = env; }
2217 
2218   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2219   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2220 
2221   // Get/set the thread's logging information
2222   CompileLog*   log()                            { return _log; }
2223   void          init_log(CompileLog* log) {
2224     // Set once, for good.
2225     assert(_log == NULL, "set only once");
2226     _log = log;
2227   }
2228 
2229   void start_idle_timer()                        { _idle_time.update(); }
2230   jlong idle_time_millis() {
2231     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2232   }
2233 
2234 #ifndef PRODUCT
2235  private:
2236   IdealGraphPrinter *_ideal_graph_printer;
2237  public:
2238   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2239   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2240 #endif
2241 
2242   // Get/set the thread's current task
2243   CompileTask* task()                      { return _task; }
2244   void         set_task(CompileTask* task) { _task = task; }
2245 };
2246 
2247 inline CompilerThread* CompilerThread::current() {
2248   return JavaThread::current()->as_CompilerThread();
2249 }
2250 
2251 // The active thread queue. It also keeps track of the current used
2252 // thread priorities.
2253 class Threads: AllStatic {
2254   friend class VMStructs;
2255  private:
2256   static int         _number_of_threads;
2257   static int         _number_of_non_daemon_threads;
2258   static int         _return_code;
2259   static uintx       _thread_claim_token;
2260 #ifdef ASSERT
2261   static bool        _vm_complete;
2262 #endif
2263 
2264   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2265   static void initialize_jsr292_core_classes(TRAPS);
2266 
2267  public:
2268   // Thread management
2269   // force_daemon is a concession to JNI, where we may need to add a
2270   // thread to the thread list before allocating its thread object
2271   static void add(JavaThread* p, bool force_daemon = false);
2272   static void remove(JavaThread* p, bool is_daemon);
2273   static void non_java_threads_do(ThreadClosure* tc);
2274   static void java_threads_do(ThreadClosure* tc);
2275   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2276   static void threads_do(ThreadClosure* tc);
2277   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2278 
2279   // Initializes the vm and creates the vm thread
2280   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2281   static void convert_vm_init_libraries_to_agents();
2282   static void create_vm_init_libraries();
2283   static void create_vm_init_agents();
2284   static void shutdown_vm_agents();
2285   static bool destroy_vm();
2286   // Supported VM versions via JNI
2287   // Includes JNI_VERSION_1_1
2288   static jboolean is_supported_jni_version_including_1_1(jint version);
2289   // Does not include JNI_VERSION_1_1
2290   static jboolean is_supported_jni_version(jint version);
2291 
2292   // The "thread claim token" provides a way for threads to be claimed
2293   // by parallel worker tasks.
2294   //
2295   // Each thread contains a "token" field. A task will claim the
2296   // thread only if its token is different from the global token,
2297   // which is updated by calling change_thread_claim_token().  When
2298   // a thread is claimed, it's token is set to the global token value
2299   // so other threads in the same iteration pass won't claim it.
2300   //
2301   // For this to work change_thread_claim_token() needs to be called
2302   // exactly once in sequential code before starting parallel tasks
2303   // that should claim threads.
2304   //
2305   // New threads get their token set to 0 and change_thread_claim_token()
2306   // never sets the global token to 0.
2307   static uintx thread_claim_token() { return _thread_claim_token; }
2308   static void change_thread_claim_token();
2309   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2310 
2311   // Apply "f->do_oop" to all root oops in all threads.
2312   // This version may only be called by sequential code.
2313   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2314   // This version may be called by sequential or parallel code.
2315   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2316 
2317   // Apply "f->do_oop" to roots in all threads that
2318   // are part of compiled frames
2319   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2320 
2321   static void convert_hcode_pointers();
2322   static void restore_hcode_pointers();
2323 
2324   // Sweeper
2325   static void nmethods_do(CodeBlobClosure* cf);
2326 
2327   // RedefineClasses support
2328   static void metadata_do(MetadataClosure* f);
2329   static void metadata_handles_do(void f(Metadata*));
2330 
2331 #ifdef ASSERT
2332   static bool is_vm_complete() { return _vm_complete; }
2333 #endif // ASSERT
2334 
2335   // Verification
2336   static void verify();
2337   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2338   static void print(bool print_stacks, bool internal_format) {
2339     // this function is only used by debug.cpp
2340     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2341   }
2342   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2343   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2344                              int buflen, bool* found_current);
2345   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2346 
2347   // Get Java threads that are waiting to enter a monitor.
2348   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2349                                                          int count, address monitor);
2350 
2351   // Get owning Java thread from the monitor's owner field.
2352   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2353                                                       address owner);
2354 
2355   // Number of threads on the active threads list
2356   static int number_of_threads()                 { return _number_of_threads; }
2357   // Number of non-daemon threads on the active threads list
2358   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2359 
2360   // Deoptimizes all frames tied to marked nmethods
2361   static void deoptimized_wrt_marked_nmethods();
2362 
2363   struct Test;                  // For private gtest access.
2364 };
2365 
2366 
2367 // Thread iterator
2368 class ThreadClosure: public StackObj {
2369  public:
2370   virtual void do_thread(Thread* thread) = 0;
2371 };
2372 
2373 class SignalHandlerMark: public StackObj {
2374  private:
2375   Thread* _thread;
2376  public:
2377   SignalHandlerMark(Thread* t) {
2378     _thread = t;
2379     if (_thread) _thread->enter_signal_handler();
2380   }
2381   ~SignalHandlerMark() {
2382     if (_thread) _thread->leave_signal_handler();
2383     _thread = NULL;
2384   }
2385 };
2386 
2387 
2388 #endif // SHARE_RUNTIME_THREAD_HPP