1 /*
   2  * Copyright (c) 1997, 2020, 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 "gc/shared/gcThreadLocalData.hpp"
  30 #include "gc/shared/threadLocalAllocBuffer.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "oops/oop.hpp"
  33 #include "prims/jvmtiExport.hpp"
  34 #include "runtime/frame.hpp"
  35 #include "runtime/globals.hpp"
  36 #include "runtime/handshake.hpp"
  37 #include "runtime/javaFrameAnchor.hpp"
  38 #include "runtime/jniHandles.hpp"
  39 #include "runtime/mutexLocker.hpp"
  40 #include "runtime/os.hpp"
  41 #include "runtime/osThread.hpp"
  42 #include "runtime/park.hpp"
  43 #include "runtime/stubRoutines.hpp"
  44 #include "runtime/threadHeapSampler.hpp"
  45 #include "runtime/threadLocalStorage.hpp"
  46 #include "runtime/threadStatisticalInfo.hpp"
  47 #include "runtime/unhandledOops.hpp"
  48 #include "utilities/align.hpp"
  49 #include "utilities/exceptions.hpp"
  50 #include "utilities/globalDefinitions.hpp"
  51 #include "utilities/macros.hpp"
  52 #if INCLUDE_JFR
  53 #include "jfr/support/jfrThreadExtension.hpp"
  54 #endif
  55 
  56 
  57 class SafeThreadsListPtr;
  58 class ThreadSafepointState;
  59 class ThreadsList;
  60 class ThreadsSMRSupport;
  61 
  62 class JvmtiRawMonitor;
  63 class JvmtiThreadState;
  64 class ThreadStatistics;
  65 class ConcurrentLocksDump;
  66 class ParkEvent;
  67 class Parker;
  68 class MonitorInfo;
  69 
  70 class AbstractCompiler;
  71 class ciEnv;
  72 class CompileThread;
  73 class CompileLog;
  74 class CompileTask;
  75 class CompileQueue;
  76 class CompilerCounters;
  77 
  78 class vframeArray;
  79 class vframe;
  80 class javaVFrame;
  81 
  82 class DeoptResourceMark;
  83 class JvmtiDeferredUpdates;
  84 
  85 class ThreadClosure;
  86 class ICRefillVerifier;
  87 class IdealGraphPrinter;
  88 
  89 class JVMCIEnv;
  90 class JVMCIPrimitiveArray;
  91 
  92 class Metadata;
  93 class ResourceArea;
  94 
  95 DEBUG_ONLY(class ResourceMark;)
  96 
  97 class WorkerThread;
  98 
  99 // Class hierarchy
 100 // - Thread
 101 //   - JavaThread
 102 //     - various subclasses eg CompilerThread, ServiceThread
 103 //   - NonJavaThread
 104 //     - NamedThread
 105 //       - VMThread
 106 //       - ConcurrentGCThread
 107 //       - WorkerThread
 108 //         - GangWorker
 109 //     - WatcherThread
 110 //     - JfrThreadSampler
 111 //
 112 // All Thread subclasses must be either JavaThread or NonJavaThread.
 113 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
 114 // a partially constructed/destroyed Thread.
 115 
 116 // Thread execution sequence and actions:
 117 // All threads:
 118 //  - thread_native_entry  // per-OS native entry point
 119 //    - stack initialization
 120 //    - other OS-level initialization (signal masks etc)
 121 //    - handshake with creating thread (if not started suspended)
 122 //    - this->call_run()  // common shared entry point
 123 //      - shared common initialization
 124 //      - this->pre_run()  // virtual per-thread-type initialization
 125 //      - this->run()      // virtual per-thread-type "main" logic
 126 //      - shared common tear-down
 127 //      - this->post_run()  // virtual per-thread-type tear-down
 128 //      - // 'this' no longer referenceable
 129 //    - OS-level tear-down (minimal)
 130 //    - final logging
 131 //
 132 // For JavaThread:
 133 //   - this->run()  // virtual but not normally overridden
 134 //     - this->thread_main_inner()  // extra call level to ensure correct stack calculations
 135 //       - this->entry_point()  // set differently for each kind of JavaThread
 136 
 137 class Thread: public ThreadShadow {
 138   friend class VMStructs;
 139   friend class JVMCIVMStructs;
 140  private:
 141 
 142 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 143   // Current thread is maintained as a thread-local variable
 144   static THREAD_LOCAL Thread* _thr_current;
 145 #endif
 146 
 147   // Thread local data area available to the GC. The internal
 148   // structure and contents of this data area is GC-specific.
 149   // Only GC and GC barrier code should access this data area.
 150   GCThreadLocalData _gc_data;
 151 
 152  public:
 153   static ByteSize gc_data_offset() {
 154     return byte_offset_of(Thread, _gc_data);
 155   }
 156 
 157   template <typename T> T* gc_data() {
 158     STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
 159     return reinterpret_cast<T*>(&_gc_data);
 160   }
 161 
 162   // Exception handling
 163   // (Note: _pending_exception and friends are in ThreadShadow)
 164   //oop       _pending_exception;                // pending exception for current thread
 165   // const char* _exception_file;                   // file information for exception (debugging only)
 166   // int         _exception_line;                   // line information for exception (debugging only)
 167  protected:
 168 
 169   DEBUG_ONLY(static Thread* _starting_thread;)
 170 
 171   // Support for forcing alignment of thread objects for biased locking
 172   void*       _real_malloc_address;
 173 
 174   // JavaThread lifecycle support:
 175   friend class SafeThreadsListPtr;  // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
 176   friend class ScanHazardPtrGatherProtectedThreadsClosure;  // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 177   friend class ScanHazardPtrGatherThreadsListClosure;  // for get_threads_hazard_ptr(), untag_hazard_ptr() access
 178   friend class ScanHazardPtrPrintMatchingThreadsClosure;  // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
 179   friend class ThreadsSMRSupport;  // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
 180 
 181   ThreadsList* volatile _threads_hazard_ptr;
 182   SafeThreadsListPtr*   _threads_list_ptr;
 183   ThreadsList*          cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
 184   ThreadsList*          get_threads_hazard_ptr();
 185   void                  set_threads_hazard_ptr(ThreadsList* new_list);
 186   static bool           is_hazard_ptr_tagged(ThreadsList* list) {
 187     return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
 188   }
 189   static ThreadsList*   tag_hazard_ptr(ThreadsList* list) {
 190     return (ThreadsList*)(intptr_t(list) | intptr_t(1));
 191   }
 192   static ThreadsList*   untag_hazard_ptr(ThreadsList* list) {
 193     return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
 194   }
 195   // This field is enabled via -XX:+EnableThreadSMRStatistics:
 196   uint _nested_threads_hazard_ptr_cnt;
 197   void dec_nested_threads_hazard_ptr_cnt() {
 198     assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
 199     _nested_threads_hazard_ptr_cnt--;
 200   }
 201   void inc_nested_threads_hazard_ptr_cnt() {
 202     _nested_threads_hazard_ptr_cnt++;
 203   }
 204   uint nested_threads_hazard_ptr_cnt() {
 205     return _nested_threads_hazard_ptr_cnt;
 206   }
 207 
 208  public:
 209   void* operator new(size_t size) throw() { return allocate(size, true); }
 210   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 211     return allocate(size, false); }
 212   void  operator delete(void* p);
 213 
 214  protected:
 215   static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 216  private:
 217 
 218   // ***************************************************************
 219   // Suspend and resume support
 220   // ***************************************************************
 221   //
 222   // VM suspend/resume no longer exists - it was once used for various
 223   // things including safepoints but was deprecated and finally removed
 224   // in Java 7. Because VM suspension was considered "internal" Java-level
 225   // suspension was considered "external", and this legacy naming scheme
 226   // remains.
 227   //
 228   // External suspend/resume requests come from JVM_SuspendThread,
 229   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 230   // ResumeThread. External
 231   // suspend requests cause _external_suspend to be set and external
 232   // resume requests cause _external_suspend to be cleared.
 233   // External suspend requests do not nest on top of other external
 234   // suspend requests. The higher level APIs reject suspend requests
 235   // for already suspended threads.
 236   //
 237   // The external_suspend
 238   // flag is checked by has_special_runtime_exit_condition() and java thread
 239   // will self-suspend when handle_special_runtime_exit_condition() is
 240   // called. Most uses of the _thread_blocked state in JavaThreads are
 241   // considered the same as being externally suspended; if the blocking
 242   // condition lifts, the JavaThread will self-suspend. Other places
 243   // where VM checks for external_suspend include:
 244   //   + mutex granting (do not enter monitors when thread is suspended)
 245   //   + state transitions from _thread_in_native
 246   //
 247   // In general, java_suspend() does not wait for an external suspend
 248   // request to complete. When it returns, the only guarantee is that
 249   // the _external_suspend field is true.
 250   //
 251   // wait_for_ext_suspend_completion() is used to wait for an external
 252   // suspend request to complete. External suspend requests are usually
 253   // followed by some other interface call that requires the thread to
 254   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 255   // the interface that requires quiescence, we give the JavaThread a
 256   // chance to self-suspend before we need it to be quiescent. This
 257   // improves overall suspend/query performance.
 258   //
 259   // _suspend_flags controls the behavior of java_ suspend/resume.
 260   // It must be set under the protection of SR_lock. Read from the flag is
 261   // OK without SR_lock as long as the value is only used as a hint.
 262   // (e.g., check _external_suspend first without lock and then recheck
 263   // inside SR_lock and finish the suspension)
 264   //
 265   // _suspend_flags is also overloaded for other "special conditions" so
 266   // that a single check indicates whether any special action is needed
 267   // eg. for async exceptions.
 268   // -------------------------------------------------------------------
 269   // Notes:
 270   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 271   // but we still update its value to keep other part of the system (mainly
 272   // JVMTI) happy. ThreadState is legacy code (see notes in
 273   // osThread.hpp).
 274   //
 275   // 2. It would be more natural if set_external_suspend() is private and
 276   // part of java_suspend(), but that probably would affect the suspend/query
 277   // performance. Need more investigation on this.
 278 
 279   // suspend/resume lock: used for self-suspend
 280   Monitor* _SR_lock;
 281 
 282  protected:
 283   enum SuspendFlags {
 284     // NOTE: avoid using the sign-bit as cc generates different test code
 285     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 286 
 287     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 288     _ext_suspended          = 0x40000000U, // thread has self-suspended
 289 
 290     _has_async_exception    = 0x00000001U, // there is a pending async exception
 291     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 292 
 293     _trace_flag             = 0x00000004U, // call tracing backend
 294     _obj_deopt              = 0x00000008U  // suspend for object reallocation and relocking for JVMTI agent
 295   };
 296 
 297   // various suspension related flags - atomically updated
 298   // overloaded for async exception checking in check_special_condition_for_native_trans.
 299   volatile uint32_t _suspend_flags;
 300 
 301  private:
 302   int _num_nested_signal;
 303 
 304   DEBUG_ONLY(bool _suspendible_thread;)
 305 
 306  public:
 307   void enter_signal_handler() { _num_nested_signal++; }
 308   void leave_signal_handler() { _num_nested_signal--; }
 309   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 310 
 311   // Determines if a heap allocation failure will be retried
 312   // (e.g., by deoptimizing and re-executing in the interpreter).
 313   // In this case, the failed allocation must raise
 314   // Universe::out_of_memory_error_retry() and omit side effects
 315   // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
 316   // and -XX:OnOutOfMemoryError.
 317   virtual bool in_retryable_allocation() const { return false; }
 318 
 319 #ifdef ASSERT
 320   void set_suspendible_thread() {
 321     _suspendible_thread = true;
 322   }
 323 
 324   void clear_suspendible_thread() {
 325     _suspendible_thread = false;
 326   }
 327 
 328   bool is_suspendible_thread() { return _suspendible_thread; }
 329 #endif
 330 
 331  private:
 332   // Active_handles points to a block of handles
 333   JNIHandleBlock* _active_handles;
 334 
 335   // One-element thread local free list
 336   JNIHandleBlock* _free_handle_block;
 337 
 338   // Point to the last handle mark
 339   HandleMark* _last_handle_mark;
 340 
 341   // Claim value for parallel iteration over threads.
 342   uintx _threads_do_token;
 343 
 344   // Support for GlobalCounter
 345  private:
 346   volatile uintx _rcu_counter;
 347  public:
 348   volatile uintx* get_rcu_counter() {
 349     return &_rcu_counter;
 350   }
 351 
 352  public:
 353   void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 354   HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 355  private:
 356 
 357 #ifdef ASSERT
 358   ICRefillVerifier* _missed_ic_stub_refill_verifier;
 359 
 360  public:
 361   ICRefillVerifier* missed_ic_stub_refill_verifier() {
 362     return _missed_ic_stub_refill_verifier;
 363   }
 364 
 365   void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
 366     _missed_ic_stub_refill_verifier = verifier;
 367   }
 368 #endif // ASSERT
 369 
 370  private:
 371 
 372   // Debug support for checking if code allows safepoints or not.
 373   // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
 374   // mutex, or blocking on an object synchronizer (Java locking).
 375   // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
 376   // the above cases.
 377   //
 378   // The class NoSafepointVerifier is used to set this counter.
 379   //
 380   NOT_PRODUCT(int _no_safepoint_count;)         // If 0, thread allow a safepoint to happen
 381 
 382  private:
 383   // Used by SkipGCALot class.
 384   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 385 
 386   friend class GCLocker;
 387   friend class NoSafepointVerifier;
 388   friend class PauseNoSafepointVerifier;
 389 
 390   volatile void* _polling_page;                 // Thread local polling page
 391 
 392   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 393   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 394                                                 // the Java heap
 395   ThreadHeapSampler _heap_sampler;              // For use when sampling the memory.
 396 
 397   ThreadStatisticalInfo _statistical_info;      // Statistics about the thread
 398 
 399   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 400 
 401   int   _vm_operation_started_count;            // VM_Operation support
 402   int   _vm_operation_completed_count;          // VM_Operation support
 403 
 404   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 405                                                 // is waiting to lock
 406   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 407   JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread
 408                                                  // is waiting to lock
 409 
 410 
 411   // ObjectMonitor on which this thread called Object.wait()
 412   ObjectMonitor* _current_waiting_monitor;
 413 
 414   // Per-thread ObjectMonitor lists:
 415  public:
 416   ObjectMonitor* om_free_list;                  // SLL of free ObjectMonitors
 417   int om_free_count;                            // # on om_free_list
 418   int om_free_provision;                        // # to try to allocate next
 419   ObjectMonitor* om_in_use_list;                // SLL of in-use ObjectMonitors
 420   int om_in_use_count;                          // # on om_in_use_list
 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_service_thread() const             { return false; }
 483   virtual bool is_hidden_from_external_view() const  { return false; }
 484   virtual bool is_jvmti_agent_thread() const         { return false; }
 485   // True iff the thread can perform GC operations at a safepoint.
 486   // Generally will be true only of VM thread and parallel GC WorkGang
 487   // threads.
 488   virtual bool is_GC_task_thread() const             { return false; }
 489   virtual bool is_Watcher_thread() const             { return false; }
 490   virtual bool is_ConcurrentGC_thread() const        { return false; }
 491   virtual bool is_Named_thread() const               { return false; }
 492   virtual bool is_Worker_thread() const              { return false; }
 493 
 494   // Can this thread make Java upcalls
 495   virtual bool can_call_java() const                 { return false; }
 496 
 497   // Is this a JavaThread that is on the VM's current ThreadsList?
 498   // If so it must participate in the safepoint protocol.
 499   virtual bool is_active_Java_thread() const         { return false; }
 500 
 501   // Casts
 502   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 503 
 504   virtual char* name() const { return (char*)"Unknown thread"; }
 505 
 506   // Returns the current thread (ASSERTS if NULL)
 507   static inline Thread* current();
 508   // Returns the current thread, or NULL if not attached
 509   static inline Thread* current_or_null();
 510   // Returns the current thread, or NULL if not attached, and is
 511   // safe for use from signal-handlers
 512   static inline Thread* current_or_null_safe();
 513 
 514   // Common thread operations
 515 #ifdef ASSERT
 516   static void check_for_dangling_thread_pointer(Thread *thread);
 517 #endif
 518   static void set_priority(Thread* thread, ThreadPriority priority);
 519   static ThreadPriority get_priority(const Thread* const thread);
 520   static void start(Thread* thread);
 521 
 522   void set_native_thread_name(const char *name) {
 523     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 524     os::set_native_thread_name(name);
 525   }
 526 
 527   Monitor* SR_lock() const                       { return _SR_lock; }
 528 
 529   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 530 
 531   inline void set_suspend_flag(SuspendFlags f);
 532   inline void clear_suspend_flag(SuspendFlags f);
 533 
 534   inline void set_has_async_exception();
 535   inline void clear_has_async_exception();
 536 
 537   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 538 
 539   inline void set_critical_native_unlock();
 540   inline void clear_critical_native_unlock();
 541 
 542   inline void set_trace_flag();
 543   inline void clear_trace_flag();
 544 
 545   inline void set_obj_deopt_flag();
 546   inline void clear_obj_deopt_flag();
 547 
 548   // Support for Unhandled Oop detection
 549   // Add the field for both, fastdebug and debug, builds to keep
 550   // Thread's fields layout the same.
 551   // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
 552 #ifdef CHECK_UNHANDLED_OOPS
 553  private:
 554   UnhandledOops* _unhandled_oops;
 555 #elif defined(ASSERT)
 556  private:
 557   void* _unhandled_oops;
 558 #endif
 559 #ifdef CHECK_UNHANDLED_OOPS
 560  public:
 561   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 562   // Mark oop safe for gc.  It may be stack allocated but won't move.
 563   void allow_unhandled_oop(oop *op) {
 564     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 565   }
 566   // Clear oops at safepoint so crashes point to unhandled oop violator
 567   void clear_unhandled_oops() {
 568     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 569   }
 570 #endif // CHECK_UNHANDLED_OOPS
 571 
 572  public:
 573 #ifndef PRODUCT
 574   bool skip_gcalot()           { return _skip_gcalot; }
 575   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 576 #endif
 577 
 578   // Installs a pending exception to be inserted later
 579   static void send_async_exception(oop thread_oop, oop java_throwable);
 580 
 581   // Resource area
 582   ResourceArea* resource_area() const            { return _resource_area; }
 583   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 584 
 585   OSThread* osthread() const                     { return _osthread;   }
 586   void set_osthread(OSThread* thread)            { _osthread = thread; }
 587 
 588   // JNI handle support
 589   JNIHandleBlock* active_handles() const         { return _active_handles; }
 590   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 591   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 592   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 593 
 594   // Internal handle support
 595   HandleArea* handle_area() const                { return _handle_area; }
 596   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 597 
 598   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 599   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 600 
 601   // Thread-Local Allocation Buffer (TLAB) support
 602   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 603   void initialize_tlab() {
 604     if (UseTLAB) {
 605       tlab().initialize();
 606     }
 607   }
 608 
 609   jlong allocated_bytes()               { return _allocated_bytes; }
 610   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 611   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 612   inline jlong cooked_allocated_bytes();
 613 
 614   ThreadHeapSampler& heap_sampler()     { return _heap_sampler; }
 615 
 616   ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
 617 
 618   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 619 
 620   bool is_trace_suspend()               { return (_suspend_flags & _trace_flag) != 0; }
 621 
 622   bool is_obj_deopt_suspend()           { return (_suspend_flags & _obj_deopt) != 0; }
 623 
 624   // VM operation support
 625   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 626   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 627   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 628 
 629   // For tracking the heavyweight monitor the thread is pending on.
 630   ObjectMonitor* current_pending_monitor() {
 631     return _current_pending_monitor;
 632   }
 633   void set_current_pending_monitor(ObjectMonitor* monitor) {
 634     _current_pending_monitor = monitor;
 635   }
 636   void set_current_pending_monitor_is_from_java(bool from_java) {
 637     _current_pending_monitor_is_from_java = from_java;
 638   }
 639   bool current_pending_monitor_is_from_java() {
 640     return _current_pending_monitor_is_from_java;
 641   }
 642 
 643   // For tracking the ObjectMonitor on which this thread called Object.wait()
 644   ObjectMonitor* current_waiting_monitor() {
 645     return _current_waiting_monitor;
 646   }
 647   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 648     _current_waiting_monitor = monitor;
 649   }
 650 
 651   // For tracking the Jvmti raw monitor the thread is pending on.
 652   JvmtiRawMonitor* current_pending_raw_monitor() {
 653     return _current_pending_raw_monitor;
 654   }
 655   void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) {
 656     _current_pending_raw_monitor = monitor;
 657   }
 658 
 659   // GC support
 660   // Apply "f->do_oop" to all root oops in "this".
 661   //   Used by JavaThread::oops_do.
 662   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 663   virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
 664 
 665   // Handles the parallel case for claim_threads_do.
 666  private:
 667   bool claim_par_threads_do(uintx claim_token);
 668  public:
 669   // Requires that "claim_token" is that of the current iteration.
 670   // If "is_par" is false, sets the token of "this" to
 671   // "claim_token", and returns "true".  If "is_par" is true,
 672   // uses an atomic instruction to set the current thread's token to
 673   // "claim_token", if it is not already.  Returns "true" iff the
 674   // calling thread does the update, this indicates that the calling thread
 675   // has claimed the thread in the current iteration.
 676   bool claim_threads_do(bool is_par, uintx claim_token) {
 677     if (!is_par) {
 678       _threads_do_token = claim_token;
 679       return true;
 680     } else {
 681       return claim_par_threads_do(claim_token);
 682     }
 683   }
 684 
 685   uintx threads_do_token() const { return _threads_do_token; }
 686 
 687   // jvmtiRedefineClasses support
 688   void metadata_handles_do(void f(Metadata*));
 689 
 690  private:
 691   // Check if address is within the given range of this thread's
 692   // stack:  stack_base() > adr >/>= limit
 693   // The check is inclusive of limit if passed true, else exclusive.
 694   bool is_in_stack_range(address adr, address limit, bool inclusive) const {
 695     assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack");
 696     return stack_base() > adr && (inclusive ? adr >= limit : adr > limit);
 697   }
 698 
 699  public:
 700   // Used by fast lock support
 701   virtual bool is_lock_owned(address adr) const;
 702 
 703   // Check if address is within the given range of this thread's
 704   // stack:  stack_base() > adr >= limit
 705   bool is_in_stack_range_incl(address adr, address limit) const {
 706     return is_in_stack_range(adr, limit, true);
 707   }
 708 
 709   // Check if address is within the given range of this thread's
 710   // stack:  stack_base() > adr > limit
 711   bool is_in_stack_range_excl(address adr, address limit) const {
 712     return is_in_stack_range(adr, limit, false);
 713   }
 714 
 715   // Check if address is in the stack mapped to this thread. Used mainly in
 716   // error reporting (so has to include guard zone) and frame printing.
 717   // Expects _stack_base to be initialized - checked with assert.
 718   bool is_in_full_stack_checked(address adr) const {
 719     return is_in_stack_range_incl(adr, stack_end());
 720   }
 721 
 722   // Like is_in_full_stack_checked but without the assertions as this
 723   // may be called in a thread before _stack_base is initialized.
 724   bool is_in_full_stack(address adr) const {
 725     address stack_end = _stack_base - _stack_size;
 726     return _stack_base > adr && adr >= stack_end;
 727   }
 728 
 729   // Check if address is in the live stack of this thread (not just for locks).
 730   // Warning: can only be called by the current thread on itself.
 731   bool is_in_live_stack(address adr) const {
 732     assert(Thread::current() == this, "is_in_live_stack can only be called from current thread");
 733     return is_in_stack_range_incl(adr, os::current_stack_pointer());
 734   }
 735 
 736   // Sets this thread as starting thread. Returns failure if thread
 737   // creation fails due to lack of memory, too many threads etc.
 738   bool set_as_starting_thread();
 739 
 740 protected:
 741   // OS data associated with the thread
 742   OSThread* _osthread;  // Platform-specific thread information
 743 
 744   // Thread local resource area for temporary allocation within the VM
 745   ResourceArea* _resource_area;
 746 
 747   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 748 
 749   // Thread local handle area for allocation of handles within the VM
 750   HandleArea* _handle_area;
 751   GrowableArray<Metadata*>* _metadata_handles;
 752 
 753   // Support for stack overflow handling, get_thread, etc.
 754   address          _stack_base;
 755   size_t           _stack_size;
 756   int              _lgrp_id;
 757 
 758   volatile void** polling_page_addr() { return &_polling_page; }
 759 
 760  public:
 761   // Stack overflow support
 762   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 763   void    set_stack_base(address base) { _stack_base = base; }
 764   size_t  stack_size() const           { return _stack_size; }
 765   void    set_stack_size(size_t size)  { _stack_size = size; }
 766   address stack_end()  const           { return stack_base() - stack_size(); }
 767   void    record_stack_base_and_size();
 768   void    register_thread_stack_with_NMT() NOT_NMT_RETURN;
 769 
 770   int     lgrp_id() const        { return _lgrp_id; }
 771   void    set_lgrp_id(int value) { _lgrp_id = value; }
 772 
 773   // Printing
 774   void print_on(outputStream* st, bool print_extended_info) const;
 775   virtual void print_on(outputStream* st) const { print_on(st, false); }
 776   void print() const;
 777   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 778   void print_value_on(outputStream* st) const;
 779 
 780   // Debug-only code
 781 #ifdef ASSERT
 782  private:
 783   // Deadlock detection support for Mutex locks. List of locks own by thread.
 784   Mutex* _owned_locks;
 785   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 786   // thus the friendship
 787   friend class Mutex;
 788   friend class Monitor;
 789 
 790  public:
 791   void print_owned_locks_on(outputStream* st) const;
 792   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 793   Mutex* owned_locks() const                     { return _owned_locks;          }
 794   bool owns_locks() const                        { return owned_locks() != NULL; }
 795 
 796   // Deadlock detection
 797   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 798   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 799 #endif // ASSERT
 800 
 801   // These functions check conditions on a JavaThread before possibly going to a safepoint,
 802   // including NoSafepointVerifier.
 803   void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
 804   void check_possible_safepoint() NOT_DEBUG_RETURN;
 805 
 806  private:
 807   volatile int _jvmti_env_iteration_count;
 808 
 809  public:
 810   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 811   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 812   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 813 
 814   // Code generation
 815   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file); }
 816   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line); }
 817   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles); }
 818 
 819   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base); }
 820   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size); }
 821 
 822   static ByteSize polling_page_offset()          { return byte_offset_of(Thread, _polling_page); }
 823 
 824   static ByteSize tlab_start_offset()            { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
 825   static ByteSize tlab_end_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
 826   static ByteSize tlab_top_offset()              { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
 827   static ByteSize tlab_pf_top_offset()           { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
 828 
 829   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes); }
 830 
 831   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 832 
 833  public:
 834   volatile intptr_t _Stalled;
 835   volatile int _TypeTag;
 836   ParkEvent * _ParkEvent;                     // for Object monitors and JVMTI raw monitors
 837   ParkEvent * _MuxEvent;                      // for low-level muxAcquire-muxRelease
 838   int NativeSyncRecursion;                    // diagnostic
 839 
 840   volatile int _OnTrap;                       // Resume-at IP delta
 841   jint _hashStateW;                           // Marsaglia Shift-XOR thread-local RNG
 842   jint _hashStateX;                           // thread-specific hashCode generator state
 843   jint _hashStateY;
 844   jint _hashStateZ;
 845 
 846   // Low-level leaf-lock primitives used to implement synchronization
 847   // and native monitor-mutex infrastructure.
 848   // Not for general synchronization use.
 849   static void SpinAcquire(volatile int * Lock, const char * Name);
 850   static void SpinRelease(volatile int * Lock);
 851   static void muxAcquire(volatile intptr_t * Lock, const char * Name);
 852   static void muxRelease(volatile intptr_t * Lock);
 853 };
 854 
 855 // Inline implementation of Thread::current()
 856 inline Thread* Thread::current() {
 857   Thread* current = current_or_null();
 858   assert(current != NULL, "Thread::current() called on detached thread");
 859   return current;
 860 }
 861 
 862 inline Thread* Thread::current_or_null() {
 863 #ifndef USE_LIBRARY_BASED_TLS_ONLY
 864   return _thr_current;
 865 #else
 866   if (ThreadLocalStorage::is_initialized()) {
 867     return ThreadLocalStorage::thread();
 868   }
 869   return NULL;
 870 #endif
 871 }
 872 
 873 inline Thread* Thread::current_or_null_safe() {
 874   if (ThreadLocalStorage::is_initialized()) {
 875     return ThreadLocalStorage::thread();
 876   }
 877   return NULL;
 878 }
 879 
 880 class NonJavaThread: public Thread {
 881   friend class VMStructs;
 882 
 883   NonJavaThread* volatile _next;
 884 
 885   class List;
 886   static List _the_list;
 887 
 888   void add_to_the_list();
 889   void remove_from_the_list();
 890 
 891  protected:
 892   virtual void pre_run();
 893   virtual void post_run();
 894 
 895  public:
 896   NonJavaThread();
 897   ~NonJavaThread();
 898 
 899   class Iterator;
 900 };
 901 
 902 // Provides iteration over the list of NonJavaThreads.
 903 // List addition occurs in pre_run(), and removal occurs in post_run(),
 904 // so that only live fully-initialized threads can be found in the list.
 905 // Threads created after an iterator is constructed will not be visited
 906 // by the iterator. The scope of an iterator is a critical section; there
 907 // must be no safepoint checks in that scope.
 908 class NonJavaThread::Iterator : public StackObj {
 909   uint _protect_enter;
 910   NonJavaThread* _current;
 911 
 912   NONCOPYABLE(Iterator);
 913 
 914 public:
 915   Iterator();
 916   ~Iterator();
 917 
 918   bool end() const { return _current == NULL; }
 919   NonJavaThread* current() const { return _current; }
 920   void step();
 921 };
 922 
 923 // Name support for threads.  non-JavaThread subclasses with multiple
 924 // uniquely named instances should derive from this.
 925 class NamedThread: public NonJavaThread {
 926   friend class VMStructs;
 927   enum {
 928     max_name_len = 64
 929   };
 930  private:
 931   char* _name;
 932   // log JavaThread being processed by oops_do
 933   JavaThread* _processed_thread;
 934   uint _gc_id; // The current GC id when a thread takes part in GC
 935 
 936  public:
 937   NamedThread();
 938   ~NamedThread();
 939   // May only be called once per thread.
 940   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 941   virtual bool is_Named_thread() const { return true; }
 942   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 943   JavaThread *processed_thread() { return _processed_thread; }
 944   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 945   virtual void print_on(outputStream* st) const;
 946 
 947   void set_gc_id(uint gc_id) { _gc_id = gc_id; }
 948   uint gc_id() { return _gc_id; }
 949 };
 950 
 951 // Worker threads are named and have an id of an assigned work.
 952 class WorkerThread: public NamedThread {
 953  private:
 954   uint _id;
 955  public:
 956   WorkerThread() : _id(0)               { }
 957   virtual bool is_Worker_thread() const { return true; }
 958 
 959   virtual WorkerThread* as_Worker_thread() const {
 960     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 961     return (WorkerThread*) this;
 962   }
 963 
 964   void set_id(uint work_id)             { _id = work_id; }
 965   uint id() const                       { return _id; }
 966 };
 967 
 968 // A single WatcherThread is used for simulating timer interrupts.
 969 class WatcherThread: public NonJavaThread {
 970   friend class VMStructs;
 971  protected:
 972   virtual void run();
 973 
 974  private:
 975   static WatcherThread* _watcher_thread;
 976 
 977   static bool _startable;
 978   // volatile due to at least one lock-free read
 979   volatile static bool _should_terminate;
 980  public:
 981   enum SomeConstants {
 982     delay_interval = 10                          // interrupt delay in milliseconds
 983   };
 984 
 985   // Constructor
 986   WatcherThread();
 987 
 988   // No destruction allowed
 989   ~WatcherThread() {
 990     guarantee(false, "WatcherThread deletion must fix the race with VM termination");
 991   }
 992 
 993   // Tester
 994   bool is_Watcher_thread() const                 { return true; }
 995 
 996   // Printing
 997   char* name() const { return (char*)"VM Periodic Task Thread"; }
 998   void print_on(outputStream* st) const;
 999   void unpark();
1000 
1001   // Returns the single instance of WatcherThread
1002   static WatcherThread* watcher_thread()         { return _watcher_thread; }
1003 
1004   // Create and start the single instance of WatcherThread, or stop it on shutdown
1005   static void start();
1006   static void stop();
1007   // Only allow start once the VM is sufficiently initialized
1008   // Otherwise the first task to enroll will trigger the start
1009   static void make_startable();
1010  private:
1011   int sleep() const;
1012 };
1013 
1014 
1015 class CompilerThread;
1016 
1017 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
1018 
1019 class JavaThread: public Thread {
1020   friend class VMStructs;
1021   friend class JVMCIVMStructs;
1022   friend class WhiteBox;
1023   friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
1024  private:
1025   bool           _on_thread_list;                // Is set when this JavaThread is added to the Threads list
1026   oop            _threadObj;                     // The Java level thread object
1027 
1028 #ifdef ASSERT
1029  private:
1030   int _java_call_counter;
1031 
1032  public:
1033   int  java_call_counter()                       { return _java_call_counter; }
1034   void inc_java_call_counter()                   { _java_call_counter++; }
1035   void dec_java_call_counter() {
1036     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
1037     _java_call_counter--;
1038   }
1039  private:  // restore original namespace restriction
1040 #endif  // ifdef ASSERT
1041 
1042 #ifndef PRODUCT
1043  public:
1044   enum {
1045     jump_ring_buffer_size = 16
1046   };
1047  private:  // restore original namespace restriction
1048 #endif
1049 
1050   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
1051 
1052   ThreadFunction _entry_point;
1053 
1054   JNIEnv        _jni_environment;
1055 
1056   // Deopt support
1057   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
1058 
1059   CompiledMethod*       _deopt_nmethod;         // CompiledMethod that is currently being deoptimized
1060   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
1061   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
1062   // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
1063   // will be carried out as soon as possible, which, in most cases, is just before deoptimization of
1064   // the frame, when control returns to it.
1065   JvmtiDeferredUpdates* _jvmti_deferred_updates;
1066 
1067   // Handshake value for fixing 6243940. We need a place for the i2c
1068   // adapter to store the callee Method*. This value is NEVER live
1069   // across a gc point so it does NOT have to be gc'd
1070   // The handshake is open ended since we can't be certain that it will
1071   // be NULLed. This is because we rarely ever see the race and end up
1072   // in handle_wrong_method which is the backend of the handshake. See
1073   // code in i2c adapters and handle_wrong_method.
1074 
1075   Method*       _callee_target;
1076 
1077   // Used to pass back results to the interpreter or generated code running Java code.
1078   oop           _vm_result;    // oop result is GC-preserved
1079   Metadata*     _vm_result_2;  // non-oop result
1080 
1081   // See ReduceInitialCardMarks: this holds the precise space interval of
1082   // the most recent slow path allocation for which compiled code has
1083   // elided card-marks for performance along the fast-path.
1084   MemRegion     _deferred_card_mark;
1085 
1086   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
1087                                                  // allocated during deoptimization
1088                                                  // and by JNI_MonitorEnter/Exit
1089 
1090   // Async. requests support
1091   enum AsyncRequests {
1092     _no_async_condition = 0,
1093     _async_exception,
1094     _async_unsafe_access_error
1095   };
1096   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1097   oop           _pending_async_exception;
1098 
1099   // Safepoint support
1100  public:                                         // Expose _thread_state for SafeFetchInt()
1101   volatile JavaThreadState _thread_state;
1102  private:
1103   ThreadSafepointState* _safepoint_state;        // Holds information about a thread during a safepoint
1104   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
1105 
1106   // JavaThread termination support
1107   enum TerminatedTypes {
1108     _not_terminated = 0xDEAD - 2,
1109     _thread_exiting,                             // JavaThread::exit() has been called for this thread
1110     _thread_terminated,                          // JavaThread is removed from thread list
1111     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
1112                                                  // only VM_Exit can set _vm_exited
1113   };
1114 
1115   // In general a JavaThread's _terminated field transitions as follows:
1116   //
1117   //   _not_terminated => _thread_exiting => _thread_terminated
1118   //
1119   // _vm_exited is a special value to cover the case of a JavaThread
1120   // executing native code after the VM itself is terminated.
1121   volatile TerminatedTypes _terminated;
1122   // suspend/resume support
1123   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
1124   jint                  _in_deopt_handler;       // count of deoptimization
1125                                                  // handlers thread is in
1126   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
1127   bool                  _do_not_unlock_if_synchronized;  // Do not unlock the receiver of a synchronized method (since it was
1128                                                          // never locked) when throwing an exception. Used by interpreter only.
1129 
1130   // JNI attach states:
1131   enum JNIAttachStates {
1132     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
1133     _attaching_via_jni,          // thread is attaching via JNI
1134     _attached_via_jni            // thread has attached via JNI
1135   };
1136 
1137   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1138   // A native thread that is attaching via JNI starts with a value
1139   // of _attaching_via_jni and transitions to _attached_via_jni.
1140   volatile JNIAttachStates _jni_attach_state;
1141 
1142  public:
1143   // State of the stack guard pages for this thread.
1144   enum StackGuardState {
1145     stack_guard_unused,         // not needed
1146     stack_guard_reserved_disabled,
1147     stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1148     stack_guard_enabled         // enabled
1149   };
1150 
1151  private:
1152 
1153 #if INCLUDE_JVMCI
1154   // The _pending_* fields below are used to communicate extra information
1155   // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1156 
1157   // Communicates the DeoptReason and DeoptAction of the uncommon trap
1158   int       _pending_deoptimization;
1159 
1160   // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1161   // before the monitor has been acquired.
1162   bool      _pending_monitorenter;
1163 
1164   // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1165   bool      _pending_transfer_to_interpreter;
1166 
1167   // True if in a runtime call from compiled code that will deoptimize
1168   // and re-execute a failed heap allocation in the interpreter.
1169   bool      _in_retryable_allocation;
1170 
1171   // An id of a speculation that JVMCI compiled code can use to further describe and
1172   // uniquely identify the  speculative optimization guarded by the uncommon trap
1173   jlong     _pending_failed_speculation;
1174 
1175   // These fields are mutually exclusive in terms of live ranges.
1176   union {
1177     // Communicates the pc at which the most recent implicit exception occurred
1178     // from the signal handler to a deoptimization stub.
1179     address   _implicit_exception_pc;
1180 
1181     // Communicates an alternative call target to an i2c stub from a JavaCall .
1182     address   _alternate_call_target;
1183   } _jvmci;
1184 
1185   // Support for high precision, thread sensitive counters in JVMCI compiled code.
1186   jlong*    _jvmci_counters;
1187 
1188  public:
1189   static jlong* _jvmci_old_thread_counters;
1190   static void collect_counters(jlong* array, int length);
1191   void resize_counters(int current_size, int new_size);
1192   static void resize_all_jvmci_counters(int new_size);
1193 
1194  private:
1195 #endif // INCLUDE_JVMCI
1196 
1197   StackGuardState  _stack_guard_state;
1198 
1199   // Precompute the limit of the stack as used in stack overflow checks.
1200   // We load it from here to simplify the stack overflow check in assembly.
1201   address          _stack_overflow_limit;
1202   address          _reserved_stack_activation;
1203 
1204   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1205   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1206   // code)
1207   volatile oop     _exception_oop;               // Exception thrown in compiled code
1208   volatile address _exception_pc;                // PC where exception happened
1209   volatile address _exception_handler_pc;        // PC for handler of exception
1210   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
1211 
1212  private:
1213   // support for JNI critical regions
1214   jint    _jni_active_critical;                  // count of entries into JNI critical region
1215 
1216   // Checked JNI: function name requires exception check
1217   char* _pending_jni_exception_check_fn;
1218 
1219   // For deadlock detection.
1220   int _depth_first_number;
1221 
1222   // JVMTI PopFrame support
1223   // This is set to popframe_pending to signal that top Java frame should be popped immediately
1224   int _popframe_condition;
1225 
1226   // If reallocation of scalar replaced objects fails, we throw OOM
1227   // and during exception propagation, pop the top
1228   // _frames_to_pop_failed_realloc frames, the ones that reference
1229   // failed reallocations.
1230   int _frames_to_pop_failed_realloc;
1231 
1232   friend class VMThread;
1233   friend class ThreadWaitTransition;
1234   friend class VM_Exit;
1235 
1236   void initialize();                             // Initialized the instance variables
1237 
1238  public:
1239   // Constructor
1240   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1241   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1242   ~JavaThread();
1243 
1244 #ifdef ASSERT
1245   // verify this JavaThread hasn't be published in the Threads::list yet
1246   void verify_not_published();
1247 #endif // ASSERT
1248 
1249   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1250   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1251     _jni_environment.functions = functionTable;
1252   }
1253   struct JNINativeInterface_* get_jni_functions() {
1254     return (struct JNINativeInterface_ *)_jni_environment.functions;
1255   }
1256 
1257   // This function is called at thread creation to allow
1258   // platform specific thread variables to be initialized.
1259   void cache_global_variables();
1260 
1261   // Executes Shutdown.shutdown()
1262   void invoke_shutdown_hooks();
1263 
1264   // Cleanup on thread exit
1265   enum ExitType {
1266     normal_exit,
1267     jni_detach
1268   };
1269   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1270 
1271   void cleanup_failed_attach_current_thread(bool is_daemon);
1272 
1273   // Testers
1274   virtual bool is_Java_thread() const            { return true;  }
1275   virtual bool can_call_java() const             { return true; }
1276 
1277   virtual bool is_active_Java_thread() const {
1278     return on_thread_list() && !is_terminated();
1279   }
1280 
1281   // Thread oop. threadObj() can be NULL for initial JavaThread
1282   // (or for threads attached via JNI)
1283   oop threadObj() const                          { return _threadObj; }
1284   void set_threadObj(oop p)                      { _threadObj = p; }
1285 
1286   // Prepare thread and add to priority queue.  If a priority is
1287   // not specified, use the priority of the thread object. Threads_lock
1288   // must be held while this function is called.
1289   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1290 
1291   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1292   address saved_exception_pc()                   { return _saved_exception_pc; }
1293 
1294 
1295   ThreadFunction entry_point() const             { return _entry_point; }
1296 
1297   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1298   void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1299 
1300   // Last frame anchor routines
1301 
1302   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1303 
1304   // last_Java_sp
1305   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1306   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1307 
1308   // last_Java_pc
1309 
1310   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1311 
1312   // Safepoint support
1313   inline JavaThreadState thread_state() const;
1314   inline void set_thread_state(JavaThreadState s);
1315   inline void set_thread_state_fence(JavaThreadState s);  // fence after setting thread state
1316   inline ThreadSafepointState* safepoint_state() const;
1317   inline void set_safepoint_state(ThreadSafepointState* state);
1318   inline bool is_at_poll_safepoint();
1319 
1320   // JavaThread termination and lifecycle support:
1321   void smr_delete();
1322   bool on_thread_list() const { return _on_thread_list; }
1323   void set_on_thread_list() { _on_thread_list = true; }
1324 
1325   // thread has called JavaThread::exit() or is terminated
1326   bool is_exiting() const;
1327   // thread is terminated (no longer on the threads list); we compare
1328   // against the two non-terminated values so that a freed JavaThread
1329   // will also be considered terminated.
1330   bool check_is_terminated(TerminatedTypes l_terminated) const {
1331     return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1332   }
1333   bool is_terminated() const;
1334   void set_terminated(TerminatedTypes t);
1335   // special for Threads::remove() which is static:
1336   void set_terminated_value();
1337   void block_if_vm_exited();
1338 
1339   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1340   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1341 
1342   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1343   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1344 
1345   inline void set_polling_page_release(void* poll_value);
1346   inline void set_polling_page(void* poll_value);
1347   inline volatile void* get_polling_page();
1348 
1349  private:
1350   // Support for thread handshake operations
1351   HandshakeState _handshake;
1352  public:
1353   void set_handshake_operation(HandshakeOperation* op) {
1354     _handshake.set_operation(op);
1355   }
1356 
1357   bool has_handshake() const {
1358     return _handshake.has_operation();
1359   }
1360 
1361   void handshake_process_by_self() {
1362     _handshake.process_by_self();
1363   }
1364 
1365   HandshakeState::ProcessResult handshake_try_process(HandshakeOperation* op) {
1366     return _handshake.try_process(op);
1367   }
1368 
1369 #ifdef ASSERT
1370   Thread* active_handshaker() const {
1371     return _handshake.active_handshaker();
1372   }
1373 #endif
1374 
1375   // Suspend/resume support for JavaThread
1376  private:
1377   inline void set_ext_suspended();
1378   inline void clear_ext_suspended();
1379 
1380   // Synchronize with another thread (most likely a JVMTI agent) that is deoptimizing objects of the
1381   // current thread, i.e. reverts optimizations based on escape analysis.
1382   void wait_for_object_deoptimization();
1383 
1384  public:
1385   void java_suspend(); // higher-level suspension logic called by the public APIs
1386   void java_resume();  // higher-level resume logic called by the public APIs
1387   int  java_suspend_self(); // low-level self-suspension mechanics
1388 
1389  private:
1390   // mid-level wrapper around java_suspend_self to set up correct state and
1391   // check for a pending safepoint at the end
1392   void java_suspend_self_with_safepoint_check();
1393 
1394  public:
1395   void check_and_wait_while_suspended() {
1396     assert(JavaThread::current() == this, "sanity check");
1397 
1398     bool do_self_suspend;
1399     do {
1400       // were we externally suspended while we were waiting?
1401       do_self_suspend = handle_special_suspend_equivalent_condition();
1402       if (do_self_suspend) {
1403         // don't surprise the thread that suspended us by returning
1404         java_suspend_self();
1405         set_suspend_equivalent();
1406       }
1407     } while (do_self_suspend);
1408   }
1409   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1410   // Check for async exception in addition to safepoint and suspend request.
1411   static void check_special_condition_for_native_trans(JavaThread *thread);
1412 
1413   // Same as check_special_condition_for_native_trans but finishes the
1414   // transition into thread_in_Java mode so that it can potentially
1415   // block.
1416   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1417 
1418   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1419   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1420     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1421     // Warning: is_ext_suspend_completed() may temporarily drop the
1422     // SR_lock to allow the thread to reach a stable thread state if
1423     // it is currently in a transient thread state.
1424     return is_ext_suspend_completed(false /* !called_by_wait */,
1425                                     SuspendRetryDelay, bits);
1426   }
1427 
1428   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1429   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1430   // passed as the count and delay parameters. Experiments with specific
1431   // calls to wait_for_ext_suspend_completion() can be done by passing
1432   // other values in the code. Experiments with all calls can be done
1433   // via the appropriate -XX options.
1434   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1435 
1436   // test for suspend - most (all?) of these should go away
1437   bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1438 
1439   inline void set_external_suspend();
1440   inline void clear_external_suspend();
1441 
1442   bool is_external_suspend() const {
1443     return (_suspend_flags & _external_suspend) != 0;
1444   }
1445   // Whenever a thread transitions from native to vm/java it must suspend
1446   // if external|deopt suspend is present.
1447   bool is_suspend_after_native() const {
1448     return (_suspend_flags & (_external_suspend | _obj_deopt JFR_ONLY(| _trace_flag))) != 0;
1449   }
1450 
1451   // external suspend request is completed
1452   bool is_ext_suspended() const {
1453     return (_suspend_flags & _ext_suspended) != 0;
1454   }
1455 
1456   bool is_external_suspend_with_lock() const {
1457     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1458     return is_external_suspend();
1459   }
1460 
1461   // Special method to handle a pending external suspend request
1462   // when a suspend equivalent condition lifts.
1463   bool handle_special_suspend_equivalent_condition() {
1464     assert(is_suspend_equivalent(),
1465            "should only be called in a suspend equivalence condition");
1466     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1467     bool ret = is_external_suspend();
1468     if (!ret) {
1469       // not about to self-suspend so clear suspend equivalence
1470       clear_suspend_equivalent();
1471     }
1472     // implied else:
1473     // We have a pending external suspend request so we leave the
1474     // suspend_equivalent flag set until java_suspend_self() sets
1475     // the ext_suspended flag and clears the suspend_equivalent
1476     // flag. This insures that wait_for_ext_suspend_completion()
1477     // will return consistent values.
1478     return ret;
1479   }
1480 
1481   // utility methods to see if we are doing some kind of suspension
1482   bool is_being_ext_suspended() const            {
1483     MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1484     return is_ext_suspended() || is_external_suspend();
1485   }
1486 
1487   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1488 
1489   void set_suspend_equivalent()                  { _suspend_equivalent = true; }
1490   void clear_suspend_equivalent()                { _suspend_equivalent = false; }
1491 
1492   // Thread.stop support
1493   void send_thread_stop(oop throwable);
1494   AsyncRequests clear_special_runtime_exit_condition() {
1495     AsyncRequests x = _special_runtime_exit_condition;
1496     _special_runtime_exit_condition = _no_async_condition;
1497     return x;
1498   }
1499 
1500   // Are any async conditions present?
1501   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1502 
1503   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1504 
1505   // these next two are also used for self-suspension and async exception support
1506   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1507 
1508   // Return true if JavaThread has an asynchronous condition or
1509   // if external suspension is requested.
1510   bool has_special_runtime_exit_condition() {
1511     // Because we don't use is_external_suspend_with_lock
1512     // it is possible that we won't see an asynchronous external suspend
1513     // request that has just gotten started, i.e., SR_lock grabbed but
1514     // _external_suspend field change either not made yet or not visible
1515     // yet. However, this is okay because the request is asynchronous and
1516     // we will see the new flag value the next time through. It's also
1517     // possible that the external suspend request is dropped after
1518     // we have checked is_external_suspend(), we will recheck its value
1519     // under SR_lock in java_suspend_self().
1520     return (_special_runtime_exit_condition != _no_async_condition) ||
1521             is_external_suspend() || is_trace_suspend() || is_obj_deopt_suspend();
1522   }
1523 
1524   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1525 
1526   inline void set_pending_async_exception(oop e);
1527 
1528   // Fast-locking support
1529   bool is_lock_owned(address adr) const;
1530 
1531   // Accessors for vframe array top
1532   // The linked list of vframe arrays are sorted on sp. This means when we
1533   // unpack the head must contain the vframe array to unpack.
1534   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1535   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1536 
1537   // Side structure for deferring update of java frame locals until deopt occurs
1538   JvmtiDeferredUpdates* deferred_updates() const      { return _jvmti_deferred_updates; }
1539   void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
1540 
1541   // These only really exist to make debugging deopt problems simpler
1542 
1543   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1544   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1545 
1546   // The special resourceMark used during deoptimization
1547 
1548   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1549   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
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;
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);
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() const {
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   // Check if address is in the usable part of the stack (excludes protected
1774   // guard pages). Can be applied to any thread and is an approximation for
1775   // using is_in_live_stack when the query has to happen from another thread.
1776   bool is_in_usable_stack(address adr) const {
1777     return is_in_stack_range_incl(adr, stack_reserved_zone_base());
1778   }
1779 
1780   // Misc. accessors/mutators
1781   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1782   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1783   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1784 
1785   // For assembly stub generation
1786   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj); }
1787   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment); }
1788   static ByteSize pending_jni_exception_check_fn_offset() {
1789     return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1790   }
1791   static ByteSize last_Java_sp_offset() {
1792     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1793   }
1794   static ByteSize last_Java_pc_offset() {
1795     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1796   }
1797   static ByteSize frame_anchor_offset() {
1798     return byte_offset_of(JavaThread, _anchor);
1799   }
1800   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target); }
1801   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result); }
1802   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2); }
1803   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state); }
1804   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc); }
1805   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread); }
1806 #if INCLUDE_JVMCI
1807   static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1808   static ByteSize pending_monitorenter_offset()  { return byte_offset_of(JavaThread, _pending_monitorenter); }
1809   static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1810   static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1811   static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1812   static ByteSize jvmci_counters_offset()        { return byte_offset_of(JavaThread, _jvmci_counters); }
1813 #endif // INCLUDE_JVMCI
1814   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop); }
1815   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc); }
1816   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1817   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1818   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1819   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state); }
1820   static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1821   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags); }
1822 
1823   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1824   static ByteSize should_post_on_exceptions_flag_offset() {
1825     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1826   }
1827   static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
1828 
1829   // Returns the jni environment for this thread
1830   JNIEnv* jni_environment()                      { return &_jni_environment; }
1831 
1832   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1833     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1834     // Only return NULL if thread is off the thread list; starting to
1835     // exit should not return NULL.
1836     if (thread_from_jni_env->is_terminated()) {
1837       thread_from_jni_env->block_if_vm_exited();
1838       return NULL;
1839     } else {
1840       return thread_from_jni_env;
1841     }
1842   }
1843 
1844   // JNI critical regions. These can nest.
1845   bool in_critical()    { return _jni_active_critical > 0; }
1846   bool in_last_critical()  { return _jni_active_critical == 1; }
1847   inline void enter_critical();
1848   void exit_critical() {
1849     assert(Thread::current() == this, "this must be current thread");
1850     _jni_active_critical--;
1851     assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1852   }
1853 
1854   // Checked JNI: is the programmer required to check for exceptions, if so specify
1855   // which function name. Returning to a Java frame should implicitly clear the
1856   // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1857   // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1858   // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1859   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1860   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1861   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1862   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1863 
1864   // For deadlock detection
1865   int depth_first_number() { return _depth_first_number; }
1866   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1867 
1868  private:
1869   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1870 
1871  public:
1872   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1873   void add_monitor_chunk(MonitorChunk* chunk);
1874   void remove_monitor_chunk(MonitorChunk* chunk);
1875   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1876   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1877   void dec_in_deopt_handler() {
1878     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1879     if (_in_deopt_handler > 0) { // robustness
1880       _in_deopt_handler--;
1881     }
1882   }
1883 
1884  private:
1885   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1886 
1887  public:
1888 
1889   // Frame iteration; calls the function f for all frames on the stack
1890   void frames_do(void f(frame*, const RegisterMap*));
1891 
1892   // Memory operations
1893   void oops_do(OopClosure* f, CodeBlobClosure* cf);
1894 
1895   // Sweeper operations
1896   virtual void nmethods_do(CodeBlobClosure* cf);
1897 
1898   // RedefineClasses Support
1899   void metadata_do(MetadataClosure* f);
1900 
1901   // Debug method asserting thread states are correct during a handshake operation.
1902   DEBUG_ONLY(void verify_states_for_handshake();)
1903 
1904   // Misc. operations
1905   char* name() const { return (char*)get_thread_name(); }
1906   void print_on(outputStream* st, bool print_extended_info) const;
1907   void print_on(outputStream* st) const { print_on(st, false); }
1908   void print() const;
1909   void print_thread_state_on(outputStream*) const      PRODUCT_RETURN;
1910   void print_on_error(outputStream* st, char* buf, int buflen) const;
1911   void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1912   void verify();
1913   const char* get_thread_name() const;
1914  protected:
1915   // factor out low-level mechanics for use in both normal and error cases
1916   virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1917  public:
1918   // Accessing frames
1919   frame last_frame() {
1920     _anchor.make_walkable(this);
1921     return pd_last_frame();
1922   }
1923   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1924 
1925   // Returns method at 'depth' java or native frames down the stack
1926   // Used for security checks
1927   Klass* security_get_caller_class(int depth);
1928 
1929   // Print stack trace in external format
1930   void print_stack_on(outputStream* st);
1931   void print_stack() { print_stack_on(tty); }
1932 
1933   // Print stack traces in various internal formats
1934   void trace_stack()                             PRODUCT_RETURN;
1935   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1936   void trace_frames()                            PRODUCT_RETURN;
1937 
1938   // Print an annotated view of the stack frames
1939   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1940   void validate_frame_layout() {
1941     print_frame_layout(0, true);
1942   }
1943 
1944   // Function for testing deoptimization
1945   void deoptimize();
1946   void make_zombies();
1947 
1948   void deoptimize_marked_methods();
1949 
1950  public:
1951   // Returns the running thread as a JavaThread
1952   static inline JavaThread* current();
1953 
1954   // Returns the active Java thread.  Do not use this if you know you are calling
1955   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1956   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1957   // operation.  You may not want that either.
1958   static JavaThread* active();
1959 
1960   inline CompilerThread* as_CompilerThread();
1961 
1962  protected:
1963   virtual void pre_run();
1964   virtual void run();
1965   void thread_main_inner();
1966   virtual void post_run();
1967 
1968 
1969  private:
1970   GrowableArray<oop>* _array_for_gc;
1971  public:
1972 
1973   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1974 
1975  public:
1976   // Thread local information maintained by JVMTI.
1977   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1978   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1979   // getter is used to get this JavaThread's JvmtiThreadState if it has
1980   // one which means NULL can be returned. JvmtiThreadState::state_for()
1981   // is used to get the specified JavaThread's JvmtiThreadState if it has
1982   // one or it allocates a new JvmtiThreadState for the JavaThread and
1983   // returns it. JvmtiThreadState::state_for() will return NULL only if
1984   // the specified JavaThread is exiting.
1985   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1986   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1987 
1988   // JVMTI PopFrame support
1989   // Setting and clearing popframe_condition
1990   // All of these enumerated values are bits. popframe_pending
1991   // indicates that a PopFrame() has been requested and not yet been
1992   // completed. popframe_processing indicates that that PopFrame() is in
1993   // the process of being completed. popframe_force_deopt_reexecution_bit
1994   // indicates that special handling is required when returning to a
1995   // deoptimized caller.
1996   enum PopCondition {
1997     popframe_inactive                      = 0x00,
1998     popframe_pending_bit                   = 0x01,
1999     popframe_processing_bit                = 0x02,
2000     popframe_force_deopt_reexecution_bit   = 0x04
2001   };
2002   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
2003   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
2004   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
2005   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
2006   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
2007   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
2008   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
2009   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
2010 
2011   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
2012   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
2013   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
2014 
2015   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
2016   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
2017   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
2018 
2019  private:
2020   // Saved incoming arguments to popped frame.
2021   // Used only when popped interpreted frame returns to deoptimized frame.
2022   void*    _popframe_preserved_args;
2023   int      _popframe_preserved_args_size;
2024 
2025  public:
2026   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
2027   void* popframe_preserved_args();
2028   ByteSize popframe_preserved_args_size();
2029   WordSize popframe_preserved_args_size_in_words();
2030   void  popframe_free_preserved_args();
2031 
2032 
2033  private:
2034   JvmtiThreadState *_jvmti_thread_state;
2035 
2036   // Used by the interpreter in fullspeed mode for frame pop, method
2037   // entry, method exit and single stepping support. This field is
2038   // only set to non-zero at a safepoint or using a direct handshake
2039   // (see EnterInterpOnlyModeClosure).
2040   // It can be set to zero asynchronously to this threads execution (i.e., without
2041   // safepoint/handshake or a lock) so we have to be very careful.
2042   // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
2043   int               _interp_only_mode;
2044 
2045  public:
2046   // used by the interpreter for fullspeed debugging support (see above)
2047   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2048   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
2049   int get_interp_only_mode()                { return _interp_only_mode; }
2050   void increment_interp_only_mode()         { ++_interp_only_mode; }
2051   void decrement_interp_only_mode()         { --_interp_only_mode; }
2052 
2053   // support for cached flag that indicates whether exceptions need to be posted for this thread
2054   // if this is false, we can avoid deoptimizing when events are thrown
2055   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2056  private:
2057   int    _should_post_on_exceptions_flag;
2058 
2059  public:
2060   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
2061   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
2062 
2063  private:
2064   ThreadStatistics *_thread_stat;
2065 
2066  public:
2067   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
2068 
2069   // Return a blocker object for which this thread is blocked parking.
2070   oop current_park_blocker();
2071 
2072  private:
2073   static size_t _stack_size_at_create;
2074 
2075  public:
2076   static inline size_t stack_size_at_create(void) {
2077     return _stack_size_at_create;
2078   }
2079   static inline void set_stack_size_at_create(size_t value) {
2080     _stack_size_at_create = value;
2081   }
2082 
2083   // Machine dependent stuff
2084 #include OS_CPU_HEADER(thread)
2085 
2086   // JSR166 per-thread parker
2087  private:
2088   Parker*    _parker;
2089  public:
2090   Parker*     parker() { return _parker; }
2091 
2092   // Biased locking support
2093  private:
2094   GrowableArray<MonitorInfo*>* _cached_monitor_info;
2095  public:
2096   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2097   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2098 
2099   // clearing/querying jni attach status
2100   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2101   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2102   inline void set_done_attaching_via_jni();
2103 
2104   // Stack dump assistance:
2105   // Track the class we want to initialize but for which we have to wait
2106   // on its init_lock() because it is already being initialized.
2107   void set_class_to_be_initialized(InstanceKlass* k);
2108   InstanceKlass* class_to_be_initialized() const;
2109 
2110 private:
2111   InstanceKlass* _class_to_be_initialized;
2112 
2113   // java.lang.Thread.sleep support
2114   ParkEvent * _SleepEvent;
2115 public:
2116   bool sleep(jlong millis);
2117 
2118   // java.lang.Thread interruption support
2119   void interrupt();
2120   bool is_interrupted(bool clear_interrupted);
2121 
2122 };
2123 
2124 // Inline implementation of JavaThread::current
2125 inline JavaThread* JavaThread::current() {
2126   Thread* thread = Thread::current();
2127   assert(thread->is_Java_thread(), "just checking");
2128   return (JavaThread*)thread;
2129 }
2130 
2131 inline CompilerThread* JavaThread::as_CompilerThread() {
2132   assert(is_Compiler_thread(), "just checking");
2133   return (CompilerThread*)this;
2134 }
2135 
2136 // Dedicated thread to sweep the code cache
2137 class CodeCacheSweeperThread : public JavaThread {
2138   CompiledMethod*       _scanned_compiled_method; // nmethod being scanned by the sweeper
2139  public:
2140   CodeCacheSweeperThread();
2141   // Track the nmethod currently being scanned by the sweeper
2142   void set_scanned_compiled_method(CompiledMethod* cm) {
2143     assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2144     _scanned_compiled_method = cm;
2145   }
2146 
2147   // Hide sweeper thread from external view.
2148   bool is_hidden_from_external_view() const { return true; }
2149 
2150   bool is_Code_cache_sweeper_thread() const { return true; }
2151 
2152   // Prevent GC from unloading _scanned_compiled_method
2153   void oops_do(OopClosure* f, CodeBlobClosure* cf);
2154   void nmethods_do(CodeBlobClosure* cf);
2155 };
2156 
2157 // A thread used for Compilation.
2158 class CompilerThread : public JavaThread {
2159   friend class VMStructs;
2160  private:
2161   CompilerCounters* _counters;
2162 
2163   ciEnv*                _env;
2164   CompileLog*           _log;
2165   CompileTask* volatile _task;  // print_threads_compiling can read this concurrently.
2166   CompileQueue*         _queue;
2167   BufferBlob*           _buffer_blob;
2168 
2169   AbstractCompiler*     _compiler;
2170   TimeStamp             _idle_time;
2171 
2172  public:
2173 
2174   static CompilerThread* current();
2175 
2176   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2177   ~CompilerThread();
2178 
2179   bool is_Compiler_thread() const                { return true; }
2180 
2181   virtual bool can_call_java() const;
2182 
2183   // Hide native compiler threads from external view.
2184   bool is_hidden_from_external_view() const      { return !can_call_java(); }
2185 
2186   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
2187   AbstractCompiler* compiler() const             { return _compiler; }
2188 
2189   CompileQueue* queue()        const             { return _queue; }
2190   CompilerCounters* counters() const             { return _counters; }
2191 
2192   // Get/set the thread's compilation environment.
2193   ciEnv*        env()                            { return _env; }
2194   void          set_env(ciEnv* env)              { _env = env; }
2195 
2196   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
2197   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; }
2198 
2199   // Get/set the thread's logging information
2200   CompileLog*   log()                            { return _log; }
2201   void          init_log(CompileLog* log) {
2202     // Set once, for good.
2203     assert(_log == NULL, "set only once");
2204     _log = log;
2205   }
2206 
2207   void start_idle_timer()                        { _idle_time.update(); }
2208   jlong idle_time_millis() {
2209     return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2210   }
2211 
2212 #ifndef PRODUCT
2213  private:
2214   IdealGraphPrinter *_ideal_graph_printer;
2215  public:
2216   IdealGraphPrinter *ideal_graph_printer()           { return _ideal_graph_printer; }
2217   void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2218 #endif
2219 
2220   // Get/set the thread's current task
2221   CompileTask* task()                      { return _task; }
2222   void         set_task(CompileTask* task) { _task = task; }
2223 };
2224 
2225 inline CompilerThread* CompilerThread::current() {
2226   return JavaThread::current()->as_CompilerThread();
2227 }
2228 
2229 // The active thread queue. It also keeps track of the current used
2230 // thread priorities.
2231 class Threads: AllStatic {
2232   friend class VMStructs;
2233  private:
2234   static int         _number_of_threads;
2235   static int         _number_of_non_daemon_threads;
2236   static int         _return_code;
2237   static uintx       _thread_claim_token;
2238 #ifdef ASSERT
2239   static bool        _vm_complete;
2240 #endif
2241 
2242   static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2243   static void initialize_jsr292_core_classes(TRAPS);
2244 
2245  public:
2246   // Thread management
2247   // force_daemon is a concession to JNI, where we may need to add a
2248   // thread to the thread list before allocating its thread object
2249   static void add(JavaThread* p, bool force_daemon = false);
2250   static void remove(JavaThread* p, bool is_daemon);
2251   static void non_java_threads_do(ThreadClosure* tc);
2252   static void java_threads_do(ThreadClosure* tc);
2253   static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2254   static void threads_do(ThreadClosure* tc);
2255   static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2256 
2257   // Initializes the vm and creates the vm thread
2258   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2259   static void convert_vm_init_libraries_to_agents();
2260   static void create_vm_init_libraries();
2261   static void create_vm_init_agents();
2262   static void shutdown_vm_agents();
2263   static bool destroy_vm();
2264   // Supported VM versions via JNI
2265   // Includes JNI_VERSION_1_1
2266   static jboolean is_supported_jni_version_including_1_1(jint version);
2267   // Does not include JNI_VERSION_1_1
2268   static jboolean is_supported_jni_version(jint version);
2269 
2270   // The "thread claim token" provides a way for threads to be claimed
2271   // by parallel worker tasks.
2272   //
2273   // Each thread contains a "token" field. A task will claim the
2274   // thread only if its token is different from the global token,
2275   // which is updated by calling change_thread_claim_token().  When
2276   // a thread is claimed, it's token is set to the global token value
2277   // so other threads in the same iteration pass won't claim it.
2278   //
2279   // For this to work change_thread_claim_token() needs to be called
2280   // exactly once in sequential code before starting parallel tasks
2281   // that should claim threads.
2282   //
2283   // New threads get their token set to 0 and change_thread_claim_token()
2284   // never sets the global token to 0.
2285   static uintx thread_claim_token() { return _thread_claim_token; }
2286   static void change_thread_claim_token();
2287   static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2288 
2289   // Apply "f->do_oop" to all root oops in all threads.
2290   // This version may only be called by sequential code.
2291   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2292   // This version may be called by sequential or parallel code.
2293   static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2294 
2295   // Sweeper
2296   static void nmethods_do(CodeBlobClosure* cf);
2297 
2298   // RedefineClasses support
2299   static void metadata_do(MetadataClosure* f);
2300   static void metadata_handles_do(void f(Metadata*));
2301 
2302 #ifdef ASSERT
2303   static bool is_vm_complete() { return _vm_complete; }
2304 #endif // ASSERT
2305 
2306   // Verification
2307   static void verify();
2308   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2309   static void print(bool print_stacks, bool internal_format) {
2310     // this function is only used by debug.cpp
2311     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2312   }
2313   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2314   static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2315                              int buflen, bool* found_current);
2316   static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2317 
2318   // Get Java threads that are waiting to enter a monitor.
2319   static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2320                                                          int count, address monitor);
2321 
2322   // Get owning Java thread from the monitor's owner field.
2323   static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2324                                                       address owner);
2325 
2326   // Number of threads on the active threads list
2327   static int number_of_threads()                 { return _number_of_threads; }
2328   // Number of non-daemon threads on the active threads list
2329   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2330 
2331   // Deoptimizes all frames tied to marked nmethods
2332   static void deoptimized_wrt_marked_nmethods();
2333 
2334   struct Test;                  // For private gtest access.
2335 };
2336 
2337 class SignalHandlerMark: public StackObj {
2338  private:
2339   Thread* _thread;
2340  public:
2341   SignalHandlerMark(Thread* t) {
2342     _thread = t;
2343     if (_thread) _thread->enter_signal_handler();
2344   }
2345   ~SignalHandlerMark() {
2346     if (_thread) _thread->leave_signal_handler();
2347     _thread = NULL;
2348   }
2349 };
2350 
2351 
2352 #endif // SHARE_RUNTIME_THREAD_HPP