1 /*
   2  * Copyright (c) 1997, 2013, 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_VM_RUNTIME_THREAD_HPP
  26 #define SHARE_VM_RUNTIME_THREAD_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/threadLocalAllocBuffer.hpp"
  30 #include "oops/oop.hpp"
  31 #include "prims/jni.h"
  32 #include "prims/jvmtiExport.hpp"
  33 #include "runtime/frame.hpp"
  34 #include "runtime/javaFrameAnchor.hpp"
  35 #include "runtime/jniHandles.hpp"
  36 #include "runtime/mutexLocker.hpp"
  37 #include "runtime/os.hpp"
  38 #include "runtime/osThread.hpp"
  39 #include "runtime/park.hpp"
  40 #include "runtime/safepoint.hpp"
  41 #include "runtime/stubRoutines.hpp"
  42 #include "runtime/threadLocalStorage.hpp"
  43 #include "runtime/unhandledOops.hpp"
  44 #include "utilities/macros.hpp"
  45 
  46 #if INCLUDE_NMT
  47 #include "services/memRecorder.hpp"
  48 #endif // INCLUDE_NMT
  49 
  50 #include "trace/tracing.hpp"
  51 #include "utilities/exceptions.hpp"
  52 #include "utilities/top.hpp"
  53 #if INCLUDE_ALL_GCS
  54 #include "gc_implementation/g1/dirtyCardQueue.hpp"
  55 #include "gc_implementation/g1/satbQueue.hpp"
  56 #endif // INCLUDE_ALL_GCS
  57 #ifdef ZERO
  58 #ifdef TARGET_ARCH_zero
  59 # include "stack_zero.hpp"
  60 #endif
  61 #endif
  62 
  63 class ThreadSafepointState;
  64 class ThreadProfiler;
  65 
  66 class JvmtiThreadState;
  67 class JvmtiGetLoadedClassesClosure;
  68 class ThreadStatistics;
  69 class ConcurrentLocksDump;
  70 class ParkEvent;
  71 class Parker;
  72 
  73 class ciEnv;
  74 class CompileThread;
  75 class CompileLog;
  76 class CompileTask;
  77 class CompileQueue;
  78 class CompilerCounters;
  79 class vframeArray;
  80 
  81 class DeoptResourceMark;
  82 class jvmtiDeferredLocalVariableSet;
  83 
  84 class GCTaskQueue;
  85 class ThreadClosure;
  86 class IdealGraphPrinter;
  87 
  88 class WorkerThread;
  89 
  90 // Class hierarchy
  91 // - Thread
  92 //   - NamedThread
  93 //     - VMThread
  94 //     - ConcurrentGCThread
  95 //     - WorkerThread
  96 //       - GangWorker
  97 //       - GCTaskThread
  98 //   - JavaThread
  99 //   - WatcherThread
 100 
 101 class Thread: public ThreadShadow {
 102   friend class VMStructs;
 103  private:
 104   // Exception handling
 105   // (Note: _pending_exception and friends are in ThreadShadow)
 106   //oop       _pending_exception;                // pending exception for current thread
 107   // const char* _exception_file;                   // file information for exception (debugging only)
 108   // int         _exception_line;                   // line information for exception (debugging only)
 109  protected:
 110   // Support for forcing alignment of thread objects for biased locking
 111   void*       _real_malloc_address;
 112  public:
 113   void* operator new(size_t size) { return allocate(size, true); }
 114   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) { return allocate(size, false); }
 115   void  operator delete(void* p);
 116 
 117  protected:
 118    static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 119  private:
 120 
 121   // ***************************************************************
 122   // Suspend and resume support
 123   // ***************************************************************
 124   //
 125   // VM suspend/resume no longer exists - it was once used for various
 126   // things including safepoints but was deprecated and finally removed
 127   // in Java 7. Because VM suspension was considered "internal" Java-level
 128   // suspension was considered "external", and this legacy naming scheme
 129   // remains.
 130   //
 131   // External suspend/resume requests come from JVM_SuspendThread,
 132   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 133   // ResumeThread. External
 134   // suspend requests cause _external_suspend to be set and external
 135   // resume requests cause _external_suspend to be cleared.
 136   // External suspend requests do not nest on top of other external
 137   // suspend requests. The higher level APIs reject suspend requests
 138   // for already suspended threads.
 139   //
 140   // The external_suspend
 141   // flag is checked by has_special_runtime_exit_condition() and java thread
 142   // will self-suspend when handle_special_runtime_exit_condition() is
 143   // called. Most uses of the _thread_blocked state in JavaThreads are
 144   // considered the same as being externally suspended; if the blocking
 145   // condition lifts, the JavaThread will self-suspend. Other places
 146   // where VM checks for external_suspend include:
 147   //   + mutex granting (do not enter monitors when thread is suspended)
 148   //   + state transitions from _thread_in_native
 149   //
 150   // In general, java_suspend() does not wait for an external suspend
 151   // request to complete. When it returns, the only guarantee is that
 152   // the _external_suspend field is true.
 153   //
 154   // wait_for_ext_suspend_completion() is used to wait for an external
 155   // suspend request to complete. External suspend requests are usually
 156   // followed by some other interface call that requires the thread to
 157   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 158   // the interface that requires quiescence, we give the JavaThread a
 159   // chance to self-suspend before we need it to be quiescent. This
 160   // improves overall suspend/query performance.
 161   //
 162   // _suspend_flags controls the behavior of java_ suspend/resume.
 163   // It must be set under the protection of SR_lock. Read from the flag is
 164   // OK without SR_lock as long as the value is only used as a hint.
 165   // (e.g., check _external_suspend first without lock and then recheck
 166   // inside SR_lock and finish the suspension)
 167   //
 168   // _suspend_flags is also overloaded for other "special conditions" so
 169   // that a single check indicates whether any special action is needed
 170   // eg. for async exceptions.
 171   // -------------------------------------------------------------------
 172   // Notes:
 173   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 174   // but we still update its value to keep other part of the system (mainly
 175   // JVMTI) happy. ThreadState is legacy code (see notes in
 176   // osThread.hpp).
 177   //
 178   // 2. It would be more natural if set_external_suspend() is private and
 179   // part of java_suspend(), but that probably would affect the suspend/query
 180   // performance. Need more investigation on this.
 181   //
 182 
 183   // suspend/resume lock: used for self-suspend
 184   Monitor* _SR_lock;
 185 
 186  protected:
 187   enum SuspendFlags {
 188     // NOTE: avoid using the sign-bit as cc generates different test code
 189     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 190 
 191     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 192     _ext_suspended          = 0x40000000U, // thread has self-suspended
 193     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 194 
 195     _has_async_exception    = 0x00000001U, // there is a pending async exception
 196     _critical_native_unlock = 0x00000002U  // Must call back to unlock JNI critical lock
 197   };
 198 
 199   // various suspension related flags - atomically updated
 200   // overloaded for async exception checking in check_special_condition_for_native_trans.
 201   volatile uint32_t _suspend_flags;
 202 
 203  private:
 204   int _num_nested_signal;
 205 
 206  public:
 207   void enter_signal_handler() { _num_nested_signal++; }
 208   void leave_signal_handler() { _num_nested_signal--; }
 209   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 210 
 211  private:
 212   // Debug tracing
 213   static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
 214 
 215   // Active_handles points to a block of handles
 216   JNIHandleBlock* _active_handles;
 217 
 218   // One-element thread local free list
 219   JNIHandleBlock* _free_handle_block;
 220 
 221   // Point to the last handle mark
 222   HandleMark* _last_handle_mark;
 223 
 224   // The parity of the last strong_roots iteration in which this thread was
 225   // claimed as a task.
 226   jint _oops_do_parity;
 227 
 228   public:
 229    void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 230    HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 231   private:
 232 
 233   // debug support for checking if code does allow safepoints or not
 234   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 235   // mutex, or blocking on an object synchronizer (Java locking).
 236   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 237   // If !allow_allocation(), then an assertion failure will happen during allocation
 238   // (Hence, !allow_safepoint() => !allow_allocation()).
 239   //
 240   // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
 241   //
 242   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 243   debug_only (int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 244 
 245   // Used by SkipGCALot class.
 246   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 247 
 248   // Record when GC is locked out via the GC_locker mechanism
 249   CHECK_UNHANDLED_OOPS_ONLY(int _gc_locked_out_count;)
 250 
 251   friend class No_Alloc_Verifier;
 252   friend class No_Safepoint_Verifier;
 253   friend class Pause_No_Safepoint_Verifier;
 254   friend class ThreadLocalStorage;
 255   friend class GC_locker;
 256 
 257   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 258   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 259                                                 // the Java heap
 260 
 261   TRACE_BUFFER _trace_buffer;                   // Thread-local buffer for tracing
 262 
 263   int   _vm_operation_started_count;            // VM_Operation support
 264   int   _vm_operation_completed_count;          // VM_Operation support
 265 
 266   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 267                                                 // is waiting to lock
 268   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 269 
 270   // ObjectMonitor on which this thread called Object.wait()
 271   ObjectMonitor* _current_waiting_monitor;
 272 
 273   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 274  public:
 275   ObjectMonitor* omFreeList;
 276   int omFreeCount;                              // length of omFreeList
 277   int omFreeProvision;                          // reload chunk size
 278   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 279   int omInUseCount;                             // length of omInUseList
 280 
 281 #ifdef ASSERT
 282  private:
 283   bool _visited_for_critical_count;
 284 
 285  public:
 286   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 287   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 288 #endif
 289 
 290  public:
 291   enum {
 292     is_definitely_current_thread = true
 293   };
 294 
 295   // Constructor
 296   Thread();
 297   virtual ~Thread();
 298 
 299   // initializtion
 300   void initialize_thread_local_storage();
 301 
 302   // thread entry point
 303   virtual void run();
 304 
 305   // Testers
 306   virtual bool is_VM_thread()       const            { return false; }
 307   virtual bool is_Java_thread()     const            { return false; }
 308   virtual bool is_Compiler_thread() const            { return false; }
 309   virtual bool is_hidden_from_external_view() const  { return false; }
 310   virtual bool is_jvmti_agent_thread() const         { return false; }
 311   // True iff the thread can perform GC operations at a safepoint.
 312   // Generally will be true only of VM thread and parallel GC WorkGang
 313   // threads.
 314   virtual bool is_GC_task_thread() const             { return false; }
 315   virtual bool is_Watcher_thread() const             { return false; }
 316   virtual bool is_ConcurrentGC_thread() const        { return false; }
 317   virtual bool is_Named_thread() const               { return false; }
 318   virtual bool is_Worker_thread() const              { return false; }
 319 
 320   // Casts
 321   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 322 
 323   virtual char* name() const { return (char*)"Unknown thread"; }
 324 
 325   // Returns the current thread
 326   static inline Thread* current();
 327 
 328   // Common thread operations
 329   static void set_priority(Thread* thread, ThreadPriority priority);
 330   static ThreadPriority get_priority(const Thread* const thread);
 331   static void start(Thread* thread);
 332   static void interrupt(Thread* thr);
 333   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 334 
 335   void set_native_thread_name(const char *name) {
 336     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 337     os::set_native_thread_name(name);
 338   }
 339 
 340   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 341   Monitor* SR_lock() const                       { return _SR_lock; }
 342 
 343   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 344 
 345   void set_suspend_flag(SuspendFlags f) {
 346     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 347     uint32_t flags;
 348     do {
 349       flags = _suspend_flags;
 350     }
 351     while (Atomic::cmpxchg((jint)(flags | f),
 352                            (volatile jint*)&_suspend_flags,
 353                            (jint)flags) != (jint)flags);
 354   }
 355   void clear_suspend_flag(SuspendFlags f) {
 356     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 357     uint32_t flags;
 358     do {
 359       flags = _suspend_flags;
 360     }
 361     while (Atomic::cmpxchg((jint)(flags & ~f),
 362                            (volatile jint*)&_suspend_flags,
 363                            (jint)flags) != (jint)flags);
 364   }
 365 
 366   void set_has_async_exception() {
 367     set_suspend_flag(_has_async_exception);
 368   }
 369   void clear_has_async_exception() {
 370     clear_suspend_flag(_has_async_exception);
 371   }
 372 
 373   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 374 
 375   void set_critical_native_unlock() {
 376     set_suspend_flag(_critical_native_unlock);
 377   }
 378   void clear_critical_native_unlock() {
 379     clear_suspend_flag(_critical_native_unlock);
 380   }
 381 
 382   // Support for Unhandled Oop detection
 383 #ifdef CHECK_UNHANDLED_OOPS
 384  private:
 385   UnhandledOops* _unhandled_oops;
 386  public:
 387   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 388   // Mark oop safe for gc.  It may be stack allocated but won't move.
 389   void allow_unhandled_oop(oop *op) {
 390     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 391   }
 392   // Clear oops at safepoint so crashes point to unhandled oop violator
 393   void clear_unhandled_oops() {
 394     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 395   }
 396   bool is_gc_locked_out() { return _gc_locked_out_count > 0; }
 397 #endif // CHECK_UNHANDLED_OOPS
 398 
 399 #ifndef PRODUCT
 400   bool skip_gcalot()           { return _skip_gcalot; }
 401   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 402 #endif
 403 
 404  public:
 405   // Installs a pending exception to be inserted later
 406   static void send_async_exception(oop thread_oop, oop java_throwable);
 407 
 408   // Resource area
 409   ResourceArea* resource_area() const            { return _resource_area; }
 410   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 411 
 412   OSThread* osthread() const                     { return _osthread;   }
 413   void set_osthread(OSThread* thread)            { _osthread = thread; }
 414 
 415   // JNI handle support
 416   JNIHandleBlock* active_handles() const         { return _active_handles; }
 417   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 418   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 419   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 420 
 421   // Internal handle support
 422   HandleArea* handle_area() const                { return _handle_area; }
 423   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 424 
 425   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 426   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 427 
 428   // Thread-Local Allocation Buffer (TLAB) support
 429   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 430   void initialize_tlab() {
 431     if (UseTLAB) {
 432       tlab().initialize();
 433     }
 434   }
 435 
 436   jlong allocated_bytes()               { return _allocated_bytes; }
 437   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 438   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 439   jlong cooked_allocated_bytes() {
 440     jlong allocated_bytes = OrderAccess::load_acquire(&_allocated_bytes);
 441     if (UseTLAB) {
 442       size_t used_bytes = tlab().used_bytes();
 443       if ((ssize_t)used_bytes > 0) {
 444         // More-or-less valid tlab.  The load_acquire above should ensure
 445         // that the result of the add is <= the instantaneous value
 446         return allocated_bytes + used_bytes;
 447       }
 448     }
 449     return allocated_bytes;
 450   }
 451 
 452   TRACE_BUFFER trace_buffer()              { return _trace_buffer; }
 453   void set_trace_buffer(TRACE_BUFFER buf)  { _trace_buffer = buf; }
 454 
 455   // VM operation support
 456   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 457   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 458   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 459 
 460   // For tracking the heavyweight monitor the thread is pending on.
 461   ObjectMonitor* current_pending_monitor() {
 462     return _current_pending_monitor;
 463   }
 464   void set_current_pending_monitor(ObjectMonitor* monitor) {
 465     _current_pending_monitor = monitor;
 466   }
 467   void set_current_pending_monitor_is_from_java(bool from_java) {
 468     _current_pending_monitor_is_from_java = from_java;
 469   }
 470   bool current_pending_monitor_is_from_java() {
 471     return _current_pending_monitor_is_from_java;
 472   }
 473 
 474   // For tracking the ObjectMonitor on which this thread called Object.wait()
 475   ObjectMonitor* current_waiting_monitor() {
 476     return _current_waiting_monitor;
 477   }
 478   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 479     _current_waiting_monitor = monitor;
 480   }
 481 
 482   // GC support
 483   // Apply "f->do_oop" to all root oops in "this".
 484   // Apply "cld_f->do_cld" to CLDs that are otherwise not kept alive.
 485   //   Used by JavaThread::oops_do.
 486   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 487   virtual void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
 488 
 489   // Handles the parallel case for the method below.
 490 private:
 491   bool claim_oops_do_par_case(int collection_parity);
 492 public:
 493   // Requires that "collection_parity" is that of the current strong roots
 494   // iteration.  If "is_par" is false, sets the parity of "this" to
 495   // "collection_parity", and returns "true".  If "is_par" is true,
 496   // uses an atomic instruction to set the current threads parity to
 497   // "collection_parity", if it is not already.  Returns "true" iff the
 498   // calling thread does the update, this indicates that the calling thread
 499   // has claimed the thread's stack as a root groop in the current
 500   // collection.
 501   bool claim_oops_do(bool is_par, int collection_parity) {
 502     if (!is_par) {
 503       _oops_do_parity = collection_parity;
 504       return true;
 505     } else {
 506       return claim_oops_do_par_case(collection_parity);
 507     }
 508   }
 509 
 510   // Sweeper support
 511   void nmethods_do(CodeBlobClosure* cf);
 512 
 513   // jvmtiRedefineClasses support
 514   void metadata_do(void f(Metadata*));
 515 
 516   // Used by fast lock support
 517   virtual bool is_lock_owned(address adr) const;
 518 
 519   // Check if address is in the stack of the thread (not just for locks).
 520   // Warning: the method can only be used on the running thread
 521   bool is_in_stack(address adr) const;
 522 
 523   // Sets this thread as starting thread. Returns failure if thread
 524   // creation fails due to lack of memory, too many threads etc.
 525   bool set_as_starting_thread();
 526 
 527  protected:
 528   // OS data associated with the thread
 529   OSThread* _osthread;  // Platform-specific thread information
 530 
 531   // Thread local resource area for temporary allocation within the VM
 532   ResourceArea* _resource_area;
 533 
 534   // Thread local handle area for allocation of handles within the VM
 535   HandleArea* _handle_area;
 536   GrowableArray<Metadata*>* _metadata_handles;
 537 
 538   // Support for stack overflow handling, get_thread, etc.
 539   address          _stack_base;
 540   size_t           _stack_size;
 541   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 542   int              _lgrp_id;
 543 
 544  public:
 545   // Stack overflow support
 546   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 547 
 548   void    set_stack_base(address base) { _stack_base = base; }
 549   size_t  stack_size() const           { return _stack_size; }
 550   void    set_stack_size(size_t size)  { _stack_size = size; }
 551   void    record_stack_base_and_size();
 552 
 553   bool    on_local_stack(address adr) const {
 554     /* QQQ this has knowledge of direction, ought to be a stack method */
 555     return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
 556   }
 557 
 558   uintptr_t self_raw_id()                    { return _self_raw_id; }
 559   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 560 
 561   int     lgrp_id() const        { return _lgrp_id; }
 562   void    set_lgrp_id(int value) { _lgrp_id = value; }
 563 
 564   // Printing
 565   void print_on(outputStream* st) const;
 566   void print() const { print_on(tty); }
 567   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 568 
 569   // Debug-only code
 570 #ifdef ASSERT
 571  private:
 572   // Deadlock detection support for Mutex locks. List of locks own by thread.
 573   Monitor* _owned_locks;
 574   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 575   // thus the friendship
 576   friend class Mutex;
 577   friend class Monitor;
 578 
 579  public:
 580   void print_owned_locks_on(outputStream* st) const;
 581   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 582   Monitor* owned_locks() const                   { return _owned_locks;          }
 583   bool owns_locks() const                        { return owned_locks() != NULL; }
 584   bool owns_locks_but_compiled_lock() const;
 585 
 586   // Deadlock detection
 587   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 588 #endif
 589 
 590   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 591 
 592  private:
 593   volatile int _jvmti_env_iteration_count;
 594 
 595  public:
 596   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 597   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 598   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 599 
 600   // Code generation
 601   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file   ); }
 602   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line   ); }
 603   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles   ); }
 604 
 605   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base ); }
 606   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size ); }
 607 
 608 #define TLAB_FIELD_OFFSET(name) \
 609   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 610 
 611   TLAB_FIELD_OFFSET(start)
 612   TLAB_FIELD_OFFSET(end)
 613   TLAB_FIELD_OFFSET(top)
 614   TLAB_FIELD_OFFSET(pf_top)
 615   TLAB_FIELD_OFFSET(size)                   // desired_size
 616   TLAB_FIELD_OFFSET(refill_waste_limit)
 617   TLAB_FIELD_OFFSET(number_of_refills)
 618   TLAB_FIELD_OFFSET(fast_refill_waste)
 619   TLAB_FIELD_OFFSET(slow_allocations)
 620 
 621 #undef TLAB_FIELD_OFFSET
 622 
 623   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes ); }
 624 
 625  public:
 626   volatile intptr_t _Stalled ;
 627   volatile int _TypeTag ;
 628   ParkEvent * _ParkEvent ;                     // for synchronized()
 629   ParkEvent * _SleepEvent ;                    // for Thread.sleep
 630   ParkEvent * _MutexEvent ;                    // for native internal Mutex/Monitor
 631   ParkEvent * _MuxEvent ;                      // for low-level muxAcquire-muxRelease
 632   int NativeSyncRecursion ;                    // diagnostic
 633 
 634   volatile int _OnTrap ;                       // Resume-at IP delta
 635   jint _hashStateW ;                           // Marsaglia Shift-XOR thread-local RNG
 636   jint _hashStateX ;                           // thread-specific hashCode generator state
 637   jint _hashStateY ;
 638   jint _hashStateZ ;
 639   void * _schedctl ;
 640 
 641   intptr_t _ScratchA, _ScratchB ;              // Scratch locations for fast-path sync code
 642   static ByteSize ScratchA_offset()            { return byte_offset_of(Thread, _ScratchA ); }
 643   static ByteSize ScratchB_offset()            { return byte_offset_of(Thread, _ScratchB ); }
 644 
 645   volatile jint rng [4] ;                      // RNG for spin loop
 646 
 647   // Low-level leaf-lock primitives used to implement synchronization
 648   // and native monitor-mutex infrastructure.
 649   // Not for general synchronization use.
 650   static void SpinAcquire (volatile int * Lock, const char * Name) ;
 651   static void SpinRelease (volatile int * Lock) ;
 652   static void muxAcquire  (volatile intptr_t * Lock, const char * Name) ;
 653   static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
 654   static void muxRelease  (volatile intptr_t * Lock) ;
 655 };
 656 
 657 // Inline implementation of Thread::current()
 658 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
 659 // startup.
 660 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
 661 // period.   This is inlined in thread_<os_family>.inline.hpp.
 662 
 663 inline Thread* Thread::current() {
 664 #ifdef ASSERT
 665 // This function is very high traffic. Define PARANOID to enable expensive
 666 // asserts.
 667 #ifdef PARANOID
 668   // Signal handler should call ThreadLocalStorage::get_thread_slow()
 669   Thread* t = ThreadLocalStorage::get_thread_slow();
 670   assert(t != NULL && !t->is_inside_signal_handler(),
 671          "Don't use Thread::current() inside signal handler");
 672 #endif
 673 #endif
 674   Thread* thread = ThreadLocalStorage::thread();
 675   assert(thread != NULL, "just checking");
 676   return thread;
 677 }
 678 
 679 // Name support for threads.  non-JavaThread subclasses with multiple
 680 // uniquely named instances should derive from this.
 681 class NamedThread: public Thread {
 682   friend class VMStructs;
 683   enum {
 684     max_name_len = 64
 685   };
 686  private:
 687   char* _name;
 688   // log JavaThread being processed by oops_do
 689   JavaThread* _processed_thread;
 690 
 691  public:
 692   NamedThread();
 693   ~NamedThread();
 694   // May only be called once per thread.
 695   void set_name(const char* format, ...);
 696   virtual bool is_Named_thread() const { return true; }
 697   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 698   JavaThread *processed_thread() { return _processed_thread; }
 699   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 700 };
 701 
 702 // Worker threads are named and have an id of an assigned work.
 703 class WorkerThread: public NamedThread {
 704 private:
 705   uint _id;
 706 public:
 707   WorkerThread() : _id(0)               { }
 708   virtual bool is_Worker_thread() const { return true; }
 709 
 710   virtual WorkerThread* as_Worker_thread() const {
 711     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 712     return (WorkerThread*) this;
 713   }
 714 
 715   void set_id(uint work_id)             { _id = work_id; }
 716   uint id() const                       { return _id; }
 717 };
 718 
 719 // A single WatcherThread is used for simulating timer interrupts.
 720 class WatcherThread: public Thread {
 721   friend class VMStructs;
 722  public:
 723   virtual void run();
 724 
 725  private:
 726   static WatcherThread* _watcher_thread;
 727 
 728   static bool _startable;
 729   volatile static bool _should_terminate; // updated without holding lock
 730  public:
 731   enum SomeConstants {
 732     delay_interval = 10                          // interrupt delay in milliseconds
 733   };
 734 
 735   // Constructor
 736   WatcherThread();
 737 
 738   // Tester
 739   bool is_Watcher_thread() const                 { return true; }
 740 
 741   // Printing
 742   char* name() const { return (char*)"VM Periodic Task Thread"; }
 743   void print_on(outputStream* st) const;
 744   void print() const { print_on(tty); }
 745   void unpark();
 746 
 747   // Returns the single instance of WatcherThread
 748   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 749 
 750   // Create and start the single instance of WatcherThread, or stop it on shutdown
 751   static void start();
 752   static void stop();
 753   // Only allow start once the VM is sufficiently initialized
 754   // Otherwise the first task to enroll will trigger the start
 755   static void make_startable();
 756 
 757  private:
 758   int sleep() const;
 759 };
 760 
 761 
 762 class CompilerThread;
 763 
 764 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 765 
 766 class JavaThread: public Thread {
 767   friend class VMStructs;
 768  private:
 769   JavaThread*    _next;                          // The next thread in the Threads list
 770   oop            _threadObj;                     // The Java level thread object
 771 
 772 #ifdef ASSERT
 773  private:
 774   int _java_call_counter;
 775 
 776  public:
 777   int  java_call_counter()                       { return _java_call_counter; }
 778   void inc_java_call_counter()                   { _java_call_counter++; }
 779   void dec_java_call_counter() {
 780     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 781     _java_call_counter--;
 782   }
 783  private:  // restore original namespace restriction
 784 #endif  // ifdef ASSERT
 785 
 786 #ifndef PRODUCT
 787  public:
 788   enum {
 789     jump_ring_buffer_size = 16
 790   };
 791  private:  // restore original namespace restriction
 792 #endif
 793 
 794   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 795 
 796   ThreadFunction _entry_point;
 797 
 798   JNIEnv        _jni_environment;
 799 
 800   // Deopt support
 801   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 802 
 803   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 804                                                  // transition out of native
 805   nmethod*       _deopt_nmethod;                 // nmethod that is currently being deoptimized
 806   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 807   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 808   // Because deoptimization is lazy we must save jvmti requests to set locals
 809   // in compiled frames until we deoptimize and we have an interpreter frame.
 810   // This holds the pointer to array (yeah like there might be more than one) of
 811   // description of compiled vframes that have locals that need to be updated.
 812   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 813 
 814   // Handshake value for fixing 6243940. We need a place for the i2c
 815   // adapter to store the callee Method*. This value is NEVER live
 816   // across a gc point so it does NOT have to be gc'd
 817   // The handshake is open ended since we can't be certain that it will
 818   // be NULLed. This is because we rarely ever see the race and end up
 819   // in handle_wrong_method which is the backend of the handshake. See
 820   // code in i2c adapters and handle_wrong_method.
 821 
 822   Method*       _callee_target;
 823 
 824   // Used to pass back results to the interpreter or generated code running Java code.
 825   oop           _vm_result;    // oop result is GC-preserved
 826   Metadata*     _vm_result_2;  // non-oop result
 827 
 828   // See ReduceInitialCardMarks: this holds the precise space interval of
 829   // the most recent slow path allocation for which compiled code has
 830   // elided card-marks for performance along the fast-path.
 831   MemRegion     _deferred_card_mark;
 832 
 833   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 834                                                  // allocated during deoptimization
 835                                                  // and by JNI_MonitorEnter/Exit
 836 
 837   // Async. requests support
 838   enum AsyncRequests {
 839     _no_async_condition = 0,
 840     _async_exception,
 841     _async_unsafe_access_error
 842   };
 843   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 844   oop           _pending_async_exception;
 845 
 846   // Safepoint support
 847  public:                                         // Expose _thread_state for SafeFetchInt()
 848   volatile JavaThreadState _thread_state;
 849  private:
 850   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 851   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 852 
 853   // JavaThread termination support
 854   enum TerminatedTypes {
 855     _not_terminated = 0xDEAD - 2,
 856     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 857     _thread_terminated,                          // JavaThread is removed from thread list
 858     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 859                                                  // only VM_Exit can set _vm_exited
 860   };
 861 
 862   // In general a JavaThread's _terminated field transitions as follows:
 863   //
 864   //   _not_terminated => _thread_exiting => _thread_terminated
 865   //
 866   // _vm_exited is a special value to cover the case of a JavaThread
 867   // executing native code after the VM itself is terminated.
 868   volatile TerminatedTypes _terminated;
 869   // suspend/resume support
 870   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 871   jint                  _in_deopt_handler;       // count of deoptimization
 872                                                  // handlers thread is in
 873   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 874   bool                  _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
 875                                                  // never locked) when throwing an exception. Used by interpreter only.
 876 
 877   // JNI attach states:
 878   enum JNIAttachStates {
 879     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 880     _attaching_via_jni,          // thread is attaching via JNI
 881     _attached_via_jni            // thread has attached via JNI
 882   };
 883 
 884   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 885   // A native thread that is attaching via JNI starts with a value
 886   // of _attaching_via_jni and transitions to _attached_via_jni.
 887   volatile JNIAttachStates _jni_attach_state;
 888 
 889  public:
 890   // State of the stack guard pages for this thread.
 891   enum StackGuardState {
 892     stack_guard_unused,         // not needed
 893     stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
 894     stack_guard_enabled         // enabled
 895   };
 896 
 897  private:
 898 
 899   StackGuardState        _stack_guard_state;
 900 
 901   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 902   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 903   // code)
 904   volatile oop     _exception_oop;               // Exception thrown in compiled code
 905   volatile address _exception_pc;                // PC where exception happened
 906   volatile address _exception_handler_pc;        // PC for handler of exception
 907   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 908 
 909   // support for compilation
 910   bool    _is_compiling;                         // is true if a compilation is active inthis thread (one compilation per thread possible)
 911 
 912   // support for JNI critical regions
 913   jint    _jni_active_critical;                  // count of entries into JNI critical region
 914 
 915   // For deadlock detection.
 916   int _depth_first_number;
 917 
 918   // JVMTI PopFrame support
 919   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 920   int _popframe_condition;
 921 
 922 #ifndef PRODUCT
 923   int _jmp_ring_index;
 924   struct {
 925       // We use intptr_t instead of address so debugger doesn't try and display strings
 926       intptr_t _target;
 927       intptr_t _instruction;
 928       const char*  _file;
 929       int _line;
 930   }   _jmp_ring[ jump_ring_buffer_size ];
 931 #endif /* PRODUCT */
 932 
 933 #if INCLUDE_ALL_GCS
 934   // Support for G1 barriers
 935 
 936   ObjPtrQueue _satb_mark_queue;          // Thread-local log for SATB barrier.
 937   // Set of all such queues.
 938   static SATBMarkQueueSet _satb_mark_queue_set;
 939 
 940   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.
 941   // Set of all such queues.
 942   static DirtyCardQueueSet _dirty_card_queue_set;
 943 
 944   void flush_barrier_queues();
 945 #endif // INCLUDE_ALL_GCS
 946 
 947   friend class VMThread;
 948   friend class ThreadWaitTransition;
 949   friend class VM_Exit;
 950 
 951   void initialize();                             // Initialized the instance variables
 952 
 953  public:
 954   // Constructor
 955   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
 956   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 957   ~JavaThread();
 958 
 959 #ifdef ASSERT
 960   // verify this JavaThread hasn't be published in the Threads::list yet
 961   void verify_not_published();
 962 #endif
 963 
 964   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 965   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 966     _jni_environment.functions = functionTable;
 967   }
 968   struct JNINativeInterface_* get_jni_functions() {
 969     return (struct JNINativeInterface_ *)_jni_environment.functions;
 970   }
 971 
 972   // This function is called at thread creation to allow
 973   // platform specific thread variables to be initialized.
 974   void cache_global_variables();
 975 
 976   // Executes Shutdown.shutdown()
 977   void invoke_shutdown_hooks();
 978 
 979   // Cleanup on thread exit
 980   enum ExitType {
 981     normal_exit,
 982     jni_detach
 983   };
 984   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
 985 
 986   void cleanup_failed_attach_current_thread();
 987 
 988   // Testers
 989   virtual bool is_Java_thread() const            { return true;  }
 990 
 991   // compilation
 992   void set_is_compiling(bool f)                  { _is_compiling = f; }
 993   bool is_compiling() const                      { return _is_compiling; }
 994 
 995   // Thread chain operations
 996   JavaThread* next() const                       { return _next; }
 997   void set_next(JavaThread* p)                   { _next = p; }
 998 
 999   // Thread oop. threadObj() can be NULL for initial JavaThread
1000   // (or for threads attached via JNI)
1001   oop threadObj() const                          { return _threadObj; }
1002   void set_threadObj(oop p)                      { _threadObj = p; }
1003 
1004   ThreadPriority java_priority() const;          // Read from threadObj()
1005 
1006   // Prepare thread and add to priority queue.  If a priority is
1007   // not specified, use the priority of the thread object. Threads_lock
1008   // must be held while this function is called.
1009   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1010 
1011   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1012   address saved_exception_pc()                   { return _saved_exception_pc; }
1013 
1014 
1015   ThreadFunction entry_point() const             { return _entry_point; }
1016 
1017   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1018   void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
1019 
1020   // Last frame anchor routines
1021 
1022   JavaFrameAnchor* frame_anchor(void)                { return &_anchor; }
1023 
1024   // last_Java_sp
1025   bool has_last_Java_frame() const                   { return _anchor.has_last_Java_frame(); }
1026   intptr_t* last_Java_sp() const                     { return _anchor.last_Java_sp(); }
1027 
1028   // last_Java_pc
1029 
1030   address last_Java_pc(void)                         { return _anchor.last_Java_pc(); }
1031 
1032   // Safepoint support
1033   JavaThreadState thread_state() const           { return _thread_state; }
1034   void set_thread_state(JavaThreadState s)       { _thread_state=s;      }
1035   ThreadSafepointState *safepoint_state() const  { return _safepoint_state;  }
1036   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1037   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1038 
1039   // thread has called JavaThread::exit() or is terminated
1040   bool is_exiting()                              { return _terminated == _thread_exiting || is_terminated(); }
1041   // thread is terminated (no longer on the threads list); we compare
1042   // against the two non-terminated values so that a freed JavaThread
1043   // will also be considered terminated.
1044   bool is_terminated()                           { return _terminated != _not_terminated && _terminated != _thread_exiting; }
1045   void set_terminated(TerminatedTypes t)         { _terminated = t; }
1046   // special for Threads::remove() which is static:
1047   void set_terminated_value()                    { _terminated = _thread_terminated; }
1048   void block_if_vm_exited();
1049 
1050   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1051   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1052 
1053   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1054   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1055 
1056 #if INCLUDE_NMT
1057   // native memory tracking
1058   inline MemRecorder* get_recorder() const          { return (MemRecorder*)_recorder; }
1059   inline void         set_recorder(MemRecorder* rc) { _recorder = rc; }
1060 
1061  private:
1062   // per-thread memory recorder
1063   MemRecorder* volatile _recorder;
1064 #endif // INCLUDE_NMT
1065 
1066   // Suspend/resume support for JavaThread
1067  private:
1068   void set_ext_suspended()       { set_suspend_flag (_ext_suspended);  }
1069   void clear_ext_suspended()     { clear_suspend_flag(_ext_suspended); }
1070 
1071  public:
1072   void java_suspend();
1073   void java_resume();
1074   int  java_suspend_self();
1075 
1076   void check_and_wait_while_suspended() {
1077     assert(JavaThread::current() == this, "sanity check");
1078 
1079     bool do_self_suspend;
1080     do {
1081       // were we externally suspended while we were waiting?
1082       do_self_suspend = handle_special_suspend_equivalent_condition();
1083       if (do_self_suspend) {
1084         // don't surprise the thread that suspended us by returning
1085         java_suspend_self();
1086         set_suspend_equivalent();
1087       }
1088     } while (do_self_suspend);
1089   }
1090   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1091   // Check for async exception in addition to safepoint and suspend request.
1092   static void check_special_condition_for_native_trans(JavaThread *thread);
1093 
1094   // Same as check_special_condition_for_native_trans but finishes the
1095   // transition into thread_in_Java mode so that it can potentially
1096   // block.
1097   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1098 
1099   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1100   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1101     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1102     // Warning: is_ext_suspend_completed() may temporarily drop the
1103     // SR_lock to allow the thread to reach a stable thread state if
1104     // it is currently in a transient thread state.
1105     return is_ext_suspend_completed(false /*!called_by_wait */,
1106                                     SuspendRetryDelay, bits);
1107   }
1108 
1109   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1110   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1111   // passed as the count and delay parameters. Experiments with specific
1112   // calls to wait_for_ext_suspend_completion() can be done by passing
1113   // other values in the code. Experiments with all calls can be done
1114   // via the appropriate -XX options.
1115   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1116 
1117   void set_external_suspend()     { set_suspend_flag  (_external_suspend); }
1118   void clear_external_suspend()   { clear_suspend_flag(_external_suspend); }
1119 
1120   void set_deopt_suspend()        { set_suspend_flag  (_deopt_suspend); }
1121   void clear_deopt_suspend()      { clear_suspend_flag(_deopt_suspend); }
1122   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1123 
1124   bool is_external_suspend() const {
1125     return (_suspend_flags & _external_suspend) != 0;
1126   }
1127   // Whenever a thread transitions from native to vm/java it must suspend
1128   // if external|deopt suspend is present.
1129   bool is_suspend_after_native() const {
1130     return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
1131   }
1132 
1133   // external suspend request is completed
1134   bool is_ext_suspended() const {
1135     return (_suspend_flags & _ext_suspended) != 0;
1136   }
1137 
1138   bool is_external_suspend_with_lock() const {
1139     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1140     return is_external_suspend();
1141   }
1142 
1143   // Special method to handle a pending external suspend request
1144   // when a suspend equivalent condition lifts.
1145   bool handle_special_suspend_equivalent_condition() {
1146     assert(is_suspend_equivalent(),
1147       "should only be called in a suspend equivalence condition");
1148     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1149     bool ret = is_external_suspend();
1150     if (!ret) {
1151       // not about to self-suspend so clear suspend equivalence
1152       clear_suspend_equivalent();
1153     }
1154     // implied else:
1155     // We have a pending external suspend request so we leave the
1156     // suspend_equivalent flag set until java_suspend_self() sets
1157     // the ext_suspended flag and clears the suspend_equivalent
1158     // flag. This insures that wait_for_ext_suspend_completion()
1159     // will return consistent values.
1160     return ret;
1161   }
1162 
1163   // utility methods to see if we are doing some kind of suspension
1164   bool is_being_ext_suspended() const            {
1165     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1166     return is_ext_suspended() || is_external_suspend();
1167   }
1168 
1169   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1170 
1171   void set_suspend_equivalent()                  { _suspend_equivalent = true; };
1172   void clear_suspend_equivalent()                { _suspend_equivalent = false; };
1173 
1174   // Thread.stop support
1175   void send_thread_stop(oop throwable);
1176   AsyncRequests clear_special_runtime_exit_condition() {
1177     AsyncRequests x = _special_runtime_exit_condition;
1178     _special_runtime_exit_condition = _no_async_condition;
1179     return x;
1180   }
1181 
1182   // Are any async conditions present?
1183   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1184 
1185   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1186 
1187   // these next two are also used for self-suspension and async exception support
1188   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1189 
1190   // Return true if JavaThread has an asynchronous condition or
1191   // if external suspension is requested.
1192   bool has_special_runtime_exit_condition() {
1193     // We call is_external_suspend() last since external suspend should
1194     // be less common. Because we don't use is_external_suspend_with_lock
1195     // it is possible that we won't see an asynchronous external suspend
1196     // request that has just gotten started, i.e., SR_lock grabbed but
1197     // _external_suspend field change either not made yet or not visible
1198     // yet. However, this is okay because the request is asynchronous and
1199     // we will see the new flag value the next time through. It's also
1200     // possible that the external suspend request is dropped after
1201     // we have checked is_external_suspend(), we will recheck its value
1202     // under SR_lock in java_suspend_self().
1203     return (_special_runtime_exit_condition != _no_async_condition) ||
1204             is_external_suspend() || is_deopt_suspend();
1205   }
1206 
1207   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1208 
1209   void set_pending_async_exception(oop e) {
1210     _pending_async_exception = e;
1211     _special_runtime_exit_condition = _async_exception;
1212     set_has_async_exception();
1213   }
1214 
1215   // Fast-locking support
1216   bool is_lock_owned(address adr) const;
1217 
1218   // Accessors for vframe array top
1219   // The linked list of vframe arrays are sorted on sp. This means when we
1220   // unpack the head must contain the vframe array to unpack.
1221   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1222   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1223 
1224   // Side structure for defering update of java frame locals until deopt occurs
1225   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1226   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1227 
1228   // These only really exist to make debugging deopt problems simpler
1229 
1230   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1231   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1232 
1233   // The special resourceMark used during deoptimization
1234 
1235   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1236   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1237 
1238   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1239   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1240   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1241 
1242   void set_deopt_nmethod(nmethod* nm)            { _deopt_nmethod = nm;   }
1243   nmethod* deopt_nmethod()                       { return _deopt_nmethod; }
1244 
1245   Method*    callee_target() const               { return _callee_target; }
1246   void set_callee_target  (Method* x)          { _callee_target   = x; }
1247 
1248   // Oop results of vm runtime calls
1249   oop  vm_result() const                         { return _vm_result; }
1250   void set_vm_result  (oop x)                    { _vm_result   = x; }
1251 
1252   Metadata*    vm_result_2() const               { return _vm_result_2; }
1253   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1254 
1255   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1256   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1257 
1258   // Exception handling for compiled methods
1259   oop      exception_oop() const                 { return _exception_oop; }
1260   address  exception_pc() const                  { return _exception_pc; }
1261   address  exception_handler_pc() const          { return _exception_handler_pc; }
1262   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1263 
1264   void set_exception_oop(oop o)                  { _exception_oop = o; }
1265   void set_exception_pc(address a)               { _exception_pc = a; }
1266   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1267   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1268 
1269   // Stack overflow support
1270   inline size_t stack_available(address cur_sp);
1271   address stack_yellow_zone_base()
1272     { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
1273   size_t  stack_yellow_zone_size()
1274     { return StackYellowPages * os::vm_page_size(); }
1275   address stack_red_zone_base()
1276     { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
1277   size_t stack_red_zone_size()
1278     { return StackRedPages * os::vm_page_size(); }
1279   bool in_stack_yellow_zone(address a)
1280     { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
1281   bool in_stack_red_zone(address a)
1282     { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
1283 
1284   void create_stack_guard_pages();
1285   void remove_stack_guard_pages();
1286 
1287   void enable_stack_yellow_zone();
1288   void disable_stack_yellow_zone();
1289   void enable_stack_red_zone();
1290   void disable_stack_red_zone();
1291 
1292   inline bool stack_guard_zone_unused();
1293   inline bool stack_yellow_zone_disabled();
1294   inline bool stack_yellow_zone_enabled();
1295 
1296   // Attempt to reguard the stack after a stack overflow may have occurred.
1297   // Returns true if (a) guard pages are not needed on this thread, (b) the
1298   // pages are already guarded, or (c) the pages were successfully reguarded.
1299   // Returns false if there is not enough stack space to reguard the pages, in
1300   // which case the caller should unwind a frame and try again.  The argument
1301   // should be the caller's (approximate) sp.
1302   bool reguard_stack(address cur_sp);
1303   // Similar to above but see if current stackpoint is out of the guard area
1304   // and reguard if possible.
1305   bool reguard_stack(void);
1306 
1307   // Misc. accessors/mutators
1308   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1309   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1310   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1311 
1312 #ifndef PRODUCT
1313   void record_jump(address target, address instr, const char* file, int line);
1314 #endif /* PRODUCT */
1315 
1316   // For assembly stub generation
1317   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj           ); }
1318 #ifndef PRODUCT
1319   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index      ); }
1320   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring            ); }
1321 #endif /* PRODUCT */
1322   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment     ); }
1323   static ByteSize last_Java_sp_offset()          {
1324     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1325   }
1326   static ByteSize last_Java_pc_offset()          {
1327     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1328   }
1329   static ByteSize frame_anchor_offset()          {
1330     return byte_offset_of(JavaThread, _anchor);
1331   }
1332   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target       ); }
1333   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result           ); }
1334   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2         ); }
1335   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state        ); }
1336   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
1337   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
1338   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
1339   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
1340   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1341   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1342   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
1343   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
1344 
1345   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1346   static ByteSize should_post_on_exceptions_flag_offset() {
1347     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1348   }
1349 
1350 #if INCLUDE_ALL_GCS
1351   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
1352   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
1353 #endif // INCLUDE_ALL_GCS
1354 
1355   // Returns the jni environment for this thread
1356   JNIEnv* jni_environment()                      { return &_jni_environment; }
1357 
1358   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1359     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1360     // Only return NULL if thread is off the thread list; starting to
1361     // exit should not return NULL.
1362     if (thread_from_jni_env->is_terminated()) {
1363        thread_from_jni_env->block_if_vm_exited();
1364        return NULL;
1365     } else {
1366        return thread_from_jni_env;
1367     }
1368   }
1369 
1370   // JNI critical regions. These can nest.
1371   bool in_critical()    { return _jni_active_critical > 0; }
1372   bool in_last_critical()  { return _jni_active_critical == 1; }
1373   void enter_critical() { assert(Thread::current() == this ||
1374                                  Thread::current()->is_VM_thread() && SafepointSynchronize::is_synchronizing(),
1375                                  "this must be current thread or synchronizing");
1376                           _jni_active_critical++; }
1377   void exit_critical()  { assert(Thread::current() == this,
1378                                  "this must be current thread");
1379                           _jni_active_critical--;
1380                           assert(_jni_active_critical >= 0,
1381                                  "JNI critical nesting problem?"); }
1382 
1383   // For deadlock detection
1384   int depth_first_number() { return _depth_first_number; }
1385   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1386 
1387  private:
1388   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1389 
1390  public:
1391   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1392   void add_monitor_chunk(MonitorChunk* chunk);
1393   void remove_monitor_chunk(MonitorChunk* chunk);
1394   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1395   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1396   void dec_in_deopt_handler()                    {
1397     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1398     if (_in_deopt_handler > 0) { // robustness
1399       _in_deopt_handler--;
1400     }
1401   }
1402 
1403  private:
1404   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1405 
1406  public:
1407 
1408   // Frame iteration; calls the function f for all frames on the stack
1409   void frames_do(void f(frame*, const RegisterMap*));
1410 
1411   // Memory operations
1412   void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1413 
1414   // Sweeper operations
1415   void nmethods_do(CodeBlobClosure* cf);
1416 
1417   // RedefineClasses Support
1418   void metadata_do(void f(Metadata*));
1419 
1420   // Memory management operations
1421   void gc_epilogue();
1422   void gc_prologue();
1423 
1424   // Misc. operations
1425   char* name() const { return (char*)get_thread_name(); }
1426   void print_on(outputStream* st) const;
1427   void print() const { print_on(tty); }
1428   void print_value();
1429   void print_thread_state_on(outputStream* ) const      PRODUCT_RETURN;
1430   void print_thread_state() const                       PRODUCT_RETURN;
1431   void print_on_error(outputStream* st, char* buf, int buflen) const;
1432   void verify();
1433   const char* get_thread_name() const;
1434 private:
1435   // factor out low-level mechanics for use in both normal and error cases
1436   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1437 public:
1438   const char* get_threadgroup_name() const;
1439   const char* get_parent_name() const;
1440 
1441   // Accessing frames
1442   frame last_frame() {
1443     _anchor.make_walkable(this);
1444     return pd_last_frame();
1445   }
1446   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1447 
1448   // Returns method at 'depth' java or native frames down the stack
1449   // Used for security checks
1450   Klass* security_get_caller_class(int depth);
1451 
1452   // Print stack trace in external format
1453   void print_stack_on(outputStream* st);
1454   void print_stack() { print_stack_on(tty); }
1455 
1456   // Print stack traces in various internal formats
1457   void trace_stack()                             PRODUCT_RETURN;
1458   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1459   void trace_frames()                            PRODUCT_RETURN;
1460   void trace_oops()                              PRODUCT_RETURN;
1461 
1462   // Print an annotated view of the stack frames
1463   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1464   void validate_frame_layout() {
1465     print_frame_layout(0, true);
1466   }
1467 
1468   // Returns the number of stack frames on the stack
1469   int depth() const;
1470 
1471   // Function for testing deoptimization
1472   void deoptimize();
1473   void make_zombies();
1474 
1475   void deoptimized_wrt_marked_nmethods();
1476 
1477   // Profiling operation (see fprofile.cpp)
1478  public:
1479    bool profile_last_Java_frame(frame* fr);
1480 
1481  private:
1482    ThreadProfiler* _thread_profiler;
1483  private:
1484    friend class FlatProfiler;                    // uses both [gs]et_thread_profiler.
1485    friend class FlatProfilerTask;                // uses get_thread_profiler.
1486    friend class ThreadProfilerMark;              // uses get_thread_profiler.
1487    ThreadProfiler* get_thread_profiler()         { return _thread_profiler; }
1488    ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
1489      ThreadProfiler* result = _thread_profiler;
1490      _thread_profiler = tp;
1491      return result;
1492    }
1493 
1494  // NMT (Native memory tracking) support.
1495  // This flag helps NMT to determine if this JavaThread will be blocked
1496  // at safepoint. If not, ThreadCritical is needed for writing memory records.
1497  // JavaThread is only safepoint visible when it is in Threads' thread list,
1498  // it is not visible until it is added to the list and becomes invisible
1499  // once it is removed from the list.
1500  public:
1501   bool is_safepoint_visible() const { return _safepoint_visible; }
1502   void set_safepoint_visible(bool visible) { _safepoint_visible = visible; }
1503  private:
1504   bool _safepoint_visible;
1505 
1506   // Static operations
1507  public:
1508   // Returns the running thread as a JavaThread
1509   static inline JavaThread* current();
1510 
1511   // Returns the active Java thread.  Do not use this if you know you are calling
1512   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1513   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1514   // operation.  You may not want that either.
1515   static JavaThread* active();
1516 
1517   inline CompilerThread* as_CompilerThread();
1518 
1519  public:
1520   virtual void run();
1521   void thread_main_inner();
1522 
1523  private:
1524   // PRIVILEGED STACK
1525   PrivilegedElement*  _privileged_stack_top;
1526   GrowableArray<oop>* _array_for_gc;
1527  public:
1528 
1529   // Returns the privileged_stack information.
1530   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1531   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1532   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1533 
1534  public:
1535   // Thread local information maintained by JVMTI.
1536   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1537   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1538   // getter is used to get this JavaThread's JvmtiThreadState if it has
1539   // one which means NULL can be returned. JvmtiThreadState::state_for()
1540   // is used to get the specified JavaThread's JvmtiThreadState if it has
1541   // one or it allocates a new JvmtiThreadState for the JavaThread and
1542   // returns it. JvmtiThreadState::state_for() will return NULL only if
1543   // the specified JavaThread is exiting.
1544   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1545   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1546   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1547   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1548 
1549   // JVMTI PopFrame support
1550   // Setting and clearing popframe_condition
1551   // All of these enumerated values are bits. popframe_pending
1552   // indicates that a PopFrame() has been requested and not yet been
1553   // completed. popframe_processing indicates that that PopFrame() is in
1554   // the process of being completed. popframe_force_deopt_reexecution_bit
1555   // indicates that special handling is required when returning to a
1556   // deoptimized caller.
1557   enum PopCondition {
1558     popframe_inactive                      = 0x00,
1559     popframe_pending_bit                   = 0x01,
1560     popframe_processing_bit                = 0x02,
1561     popframe_force_deopt_reexecution_bit   = 0x04
1562   };
1563   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1564   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1565   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1566   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1567   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1568   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1569   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1570   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1571 #ifdef CC_INTERP
1572   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1573   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1574   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1575   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1576   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1577 #endif
1578 
1579  private:
1580   // Saved incoming arguments to popped frame.
1581   // Used only when popped interpreted frame returns to deoptimized frame.
1582   void*    _popframe_preserved_args;
1583   int      _popframe_preserved_args_size;
1584 
1585  public:
1586   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1587   void* popframe_preserved_args();
1588   ByteSize popframe_preserved_args_size();
1589   WordSize popframe_preserved_args_size_in_words();
1590   void  popframe_free_preserved_args();
1591 
1592 
1593  private:
1594   JvmtiThreadState *_jvmti_thread_state;
1595   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1596 
1597   // Used by the interpreter in fullspeed mode for frame pop, method
1598   // entry, method exit and single stepping support. This field is
1599   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1600   // It can be set to zero asynchronously (i.e., without a VM operation
1601   // or a lock) so we have to be very careful.
1602   int               _interp_only_mode;
1603 
1604  public:
1605   // used by the interpreter for fullspeed debugging support (see above)
1606   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1607   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1608   int get_interp_only_mode()                { return _interp_only_mode; }
1609   void increment_interp_only_mode()         { ++_interp_only_mode; }
1610   void decrement_interp_only_mode()         { --_interp_only_mode; }
1611 
1612   // support for cached flag that indicates whether exceptions need to be posted for this thread
1613   // if this is false, we can avoid deoptimizing when events are thrown
1614   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1615  private:
1616   int    _should_post_on_exceptions_flag;
1617 
1618  public:
1619   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1620   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1621 
1622  private:
1623   ThreadStatistics *_thread_stat;
1624 
1625  public:
1626   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1627 
1628   // Return a blocker object for which this thread is blocked parking.
1629   oop current_park_blocker();
1630 
1631  private:
1632   static size_t _stack_size_at_create;
1633 
1634  public:
1635   static inline size_t stack_size_at_create(void) {
1636     return _stack_size_at_create;
1637   }
1638   static inline void set_stack_size_at_create(size_t value) {
1639     _stack_size_at_create = value;
1640   }
1641 
1642 #if INCLUDE_ALL_GCS
1643   // SATB marking queue support
1644   ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
1645   static SATBMarkQueueSet& satb_mark_queue_set() {
1646     return _satb_mark_queue_set;
1647   }
1648 
1649   // Dirty card queue support
1650   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
1651   static DirtyCardQueueSet& dirty_card_queue_set() {
1652     return _dirty_card_queue_set;
1653   }
1654 #endif // INCLUDE_ALL_GCS
1655 
1656   // This method initializes the SATB and dirty card queues before a
1657   // JavaThread is added to the Java thread list. Right now, we don't
1658   // have to do anything to the dirty card queue (it should have been
1659   // activated when the thread was created), but we have to activate
1660   // the SATB queue if the thread is created while a marking cycle is
1661   // in progress. The activation / de-activation of the SATB queues at
1662   // the beginning / end of a marking cycle is done during safepoints
1663   // so we have to make sure this method is called outside one to be
1664   // able to safely read the active field of the SATB queue set. Right
1665   // now, it is called just before the thread is added to the Java
1666   // thread list in the Threads::add() method. That method is holding
1667   // the Threads_lock which ensures we are outside a safepoint. We
1668   // cannot do the obvious and set the active field of the SATB queue
1669   // when the thread is created given that, in some cases, safepoints
1670   // might happen between the JavaThread constructor being called and the
1671   // thread being added to the Java thread list (an example of this is
1672   // when the structure for the DestroyJavaVM thread is created).
1673 #if INCLUDE_ALL_GCS
1674   void initialize_queues();
1675 #else  // INCLUDE_ALL_GCS
1676   void initialize_queues() { }
1677 #endif // INCLUDE_ALL_GCS
1678 
1679   // Machine dependent stuff
1680 #ifdef TARGET_OS_ARCH_linux_x86
1681 # include "thread_linux_x86.hpp"
1682 #endif
1683 #ifdef TARGET_OS_ARCH_linux_sparc
1684 # include "thread_linux_sparc.hpp"
1685 #endif
1686 #ifdef TARGET_OS_ARCH_linux_zero
1687 # include "thread_linux_zero.hpp"
1688 #endif
1689 #ifdef TARGET_OS_ARCH_solaris_x86
1690 # include "thread_solaris_x86.hpp"
1691 #endif
1692 #ifdef TARGET_OS_ARCH_solaris_sparc
1693 # include "thread_solaris_sparc.hpp"
1694 #endif
1695 #ifdef TARGET_OS_ARCH_windows_x86
1696 # include "thread_windows_x86.hpp"
1697 #endif
1698 #ifdef TARGET_OS_ARCH_linux_arm
1699 # include "thread_linux_arm.hpp"
1700 #endif
1701 #ifdef TARGET_OS_ARCH_linux_ppc
1702 # include "thread_linux_ppc.hpp"
1703 #endif
1704 #ifdef TARGET_OS_ARCH_bsd_x86
1705 # include "thread_bsd_x86.hpp"
1706 #endif
1707 #ifdef TARGET_OS_ARCH_bsd_zero
1708 # include "thread_bsd_zero.hpp"
1709 #endif
1710 
1711 
1712  public:
1713   void set_blocked_on_compilation(bool value) {
1714     _blocked_on_compilation = value;
1715   }
1716 
1717   bool blocked_on_compilation() {
1718     return _blocked_on_compilation;
1719   }
1720  protected:
1721   bool         _blocked_on_compilation;
1722 
1723 
1724   // JSR166 per-thread parker
1725 private:
1726   Parker*    _parker;
1727 public:
1728   Parker*     parker() { return _parker; }
1729 
1730   // Biased locking support
1731 private:
1732   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1733 public:
1734   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1735   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1736 
1737   // clearing/querying jni attach status
1738   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1739   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1740   void set_done_attaching_via_jni() { _jni_attach_state = _attached_via_jni; OrderAccess::fence(); }
1741 private:
1742   // This field is used to determine if a thread has claimed
1743   // a par_id: it is -1 if the thread has not claimed a par_id;
1744   // otherwise its value is the par_id that has been claimed.
1745   int _claimed_par_id;
1746 public:
1747   int get_claimed_par_id() { return _claimed_par_id; }
1748   void set_claimed_par_id(int id) { _claimed_par_id = id;}
1749 };
1750 
1751 // Inline implementation of JavaThread::current
1752 inline JavaThread* JavaThread::current() {
1753   Thread* thread = ThreadLocalStorage::thread();
1754   assert(thread != NULL && thread->is_Java_thread(), "just checking");
1755   return (JavaThread*)thread;
1756 }
1757 
1758 inline CompilerThread* JavaThread::as_CompilerThread() {
1759   assert(is_Compiler_thread(), "just checking");
1760   return (CompilerThread*)this;
1761 }
1762 
1763 inline bool JavaThread::stack_guard_zone_unused() {
1764   return _stack_guard_state == stack_guard_unused;
1765 }
1766 
1767 inline bool JavaThread::stack_yellow_zone_disabled() {
1768   return _stack_guard_state == stack_guard_yellow_disabled;
1769 }
1770 
1771 inline bool JavaThread::stack_yellow_zone_enabled() {
1772 #ifdef ASSERT
1773   if (os::uses_stack_guard_pages()) {
1774     assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
1775   }
1776 #endif
1777     return _stack_guard_state == stack_guard_enabled;
1778 }
1779 
1780 inline size_t JavaThread::stack_available(address cur_sp) {
1781   // This code assumes java stacks grow down
1782   address low_addr; // Limit on the address for deepest stack depth
1783   if ( _stack_guard_state == stack_guard_unused) {
1784     low_addr =  stack_base() - stack_size();
1785   } else {
1786     low_addr = stack_yellow_zone_base();
1787   }
1788   return cur_sp > low_addr ? cur_sp - low_addr : 0;
1789 }
1790 
1791 // A thread used for Compilation.
1792 class CompilerThread : public JavaThread {
1793   friend class VMStructs;
1794  private:
1795   CompilerCounters* _counters;
1796 
1797   ciEnv*        _env;
1798   CompileLog*   _log;
1799   CompileTask*  _task;
1800   CompileQueue* _queue;
1801   BufferBlob*   _buffer_blob;
1802 
1803   nmethod*      _scanned_nmethod;  // nmethod being scanned by the sweeper
1804 
1805  public:
1806 
1807   static CompilerThread* current();
1808 
1809   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
1810 
1811   bool is_Compiler_thread() const                { return true; }
1812   // Hide this compiler thread from external view.
1813   bool is_hidden_from_external_view() const      { return true; }
1814 
1815   CompileQueue* queue()                          { return _queue; }
1816   CompilerCounters* counters()                   { return _counters; }
1817 
1818   // Get/set the thread's compilation environment.
1819   ciEnv*        env()                            { return _env; }
1820   void          set_env(ciEnv* env)              { _env = env; }
1821 
1822   BufferBlob*   get_buffer_blob()                { return _buffer_blob; }
1823   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
1824 
1825   // Get/set the thread's logging information
1826   CompileLog*   log()                            { return _log; }
1827   void          init_log(CompileLog* log) {
1828     // Set once, for good.
1829     assert(_log == NULL, "set only once");
1830     _log = log;
1831   }
1832 
1833   // GC support
1834   // Apply "f->do_oop" to all root oops in "this".
1835   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
1836   void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1837 
1838 #ifndef PRODUCT
1839 private:
1840   IdealGraphPrinter *_ideal_graph_printer;
1841 public:
1842   IdealGraphPrinter *ideal_graph_printer()                       { return _ideal_graph_printer; }
1843   void set_ideal_graph_printer(IdealGraphPrinter *n)             { _ideal_graph_printer = n; }
1844 #endif
1845 
1846   // Get/set the thread's current task
1847   CompileTask*  task()                           { return _task; }
1848   void          set_task(CompileTask* task)      { _task = task; }
1849 
1850   // Track the nmethod currently being scanned by the sweeper
1851   void          set_scanned_nmethod(nmethod* nm) {
1852     assert(_scanned_nmethod == NULL || nm == NULL, "should reset to NULL before writing a new value");
1853     _scanned_nmethod = nm;
1854   }
1855 };
1856 
1857 inline CompilerThread* CompilerThread::current() {
1858   return JavaThread::current()->as_CompilerThread();
1859 }
1860 
1861 
1862 // The active thread queue. It also keeps track of the current used
1863 // thread priorities.
1864 class Threads: AllStatic {
1865   friend class VMStructs;
1866  private:
1867   static JavaThread* _thread_list;
1868   static int         _number_of_threads;
1869   static int         _number_of_non_daemon_threads;
1870   static int         _return_code;
1871 #ifdef ASSERT
1872   static bool        _vm_complete;
1873 #endif
1874 
1875  public:
1876   // Thread management
1877   // force_daemon is a concession to JNI, where we may need to add a
1878   // thread to the thread list before allocating its thread object
1879   static void add(JavaThread* p, bool force_daemon = false);
1880   static void remove(JavaThread* p);
1881   static bool includes(JavaThread* p);
1882   static JavaThread* first()                     { return _thread_list; }
1883   static void threads_do(ThreadClosure* tc);
1884 
1885   // Initializes the vm and creates the vm thread
1886   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1887   static void convert_vm_init_libraries_to_agents();
1888   static void create_vm_init_libraries();
1889   static void create_vm_init_agents();
1890   static void shutdown_vm_agents();
1891   static bool destroy_vm();
1892   // Supported VM versions via JNI
1893   // Includes JNI_VERSION_1_1
1894   static jboolean is_supported_jni_version_including_1_1(jint version);
1895   // Does not include JNI_VERSION_1_1
1896   static jboolean is_supported_jni_version(jint version);
1897 
1898   // Garbage collection
1899   static void follow_other_roots(void f(oop*));
1900 
1901   // Apply "f->do_oop" to all root oops in all threads.
1902   // This version may only be called by sequential code.
1903   static void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1904   // This version may be called by sequential or parallel code.
1905   static void possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1906   // This creates a list of GCTasks, one per thread.
1907   static void create_thread_roots_tasks(GCTaskQueue* q);
1908   // This creates a list of GCTasks, one per thread, for marking objects.
1909   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
1910 
1911   // Apply "f->do_oop" to roots in all threads that
1912   // are part of compiled frames
1913   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
1914 
1915   static void convert_hcode_pointers();
1916   static void restore_hcode_pointers();
1917 
1918   // Sweeper
1919   static void nmethods_do(CodeBlobClosure* cf);
1920 
1921   // RedefineClasses support
1922   static void metadata_do(void f(Metadata*));
1923 
1924   static void gc_epilogue();
1925   static void gc_prologue();
1926 #ifdef ASSERT
1927   static bool is_vm_complete() { return _vm_complete; }
1928 #endif
1929 
1930   // Verification
1931   static void verify();
1932   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
1933   static void print(bool print_stacks, bool internal_format) {
1934     // this function is only used by debug.cpp
1935     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
1936   }
1937   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
1938 
1939   // Get Java threads that are waiting to enter a monitor. If doLock
1940   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1941   // VM needs to be at a safepoint.
1942   static GrowableArray<JavaThread*>* get_pending_threads(int count,
1943     address monitor, bool doLock);
1944 
1945   // Get owning Java thread from the monitor's owner field. If doLock
1946   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1947   // VM needs to be at a safepoint.
1948   static JavaThread *owning_thread_from_monitor_owner(address owner,
1949     bool doLock);
1950 
1951   // Number of threads on the active threads list
1952   static int number_of_threads()                 { return _number_of_threads; }
1953   // Number of non-daemon threads on the active threads list
1954   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
1955 
1956   // Deoptimizes all frames tied to marked nmethods
1957   static void deoptimized_wrt_marked_nmethods();
1958 
1959 };
1960 
1961 
1962 // Thread iterator
1963 class ThreadClosure: public StackObj {
1964  public:
1965   virtual void do_thread(Thread* thread) = 0;
1966 };
1967 
1968 class SignalHandlerMark: public StackObj {
1969 private:
1970   Thread* _thread;
1971 public:
1972   SignalHandlerMark(Thread* t) {
1973     _thread = t;
1974     if (_thread) _thread->enter_signal_handler();
1975   }
1976   ~SignalHandlerMark() {
1977     if (_thread) _thread->leave_signal_handler();
1978     _thread = NULL;
1979   }
1980 };
1981 
1982 
1983 #endif // SHARE_VM_RUNTIME_THREAD_HPP