1 /*
   2  * Copyright (c) 1997, 2018, 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/thread_ext.hpp"
  44 #include "runtime/unhandledOops.hpp"
  45 #include "trace/traceBackend.hpp"
  46 #include "trace/traceMacros.hpp"
  47 #include "utilities/exceptions.hpp"
  48 #include "utilities/macros.hpp"
  49 #include "utilities/top.hpp"
  50 #if INCLUDE_ALL_GCS
  51 #include "gc_implementation/g1/dirtyCardQueue.hpp"
  52 #include "gc_implementation/g1/satbQueue.hpp"
  53 #endif // INCLUDE_ALL_GCS
  54 #ifdef TARGET_ARCH_zero
  55 # include "stack_zero.hpp"
  56 #endif
  57 
  58 class ThreadSafepointState;
  59 class ThreadProfiler;
  60 
  61 class JvmtiThreadState;
  62 class JvmtiGetLoadedClassesClosure;
  63 class ThreadStatistics;
  64 class ConcurrentLocksDump;
  65 class ParkEvent;
  66 class Parker;
  67 
  68 class ciEnv;
  69 class CompileThread;
  70 class CompileLog;
  71 class CompileTask;
  72 class CompileQueue;
  73 class CompilerCounters;
  74 class vframeArray;
  75 
  76 class DeoptResourceMark;
  77 class jvmtiDeferredLocalVariableSet;
  78 
  79 class GCTaskQueue;
  80 class ThreadClosure;
  81 class IdealGraphPrinter;
  82 
  83 class Metadata;
  84 template <class T, MEMFLAGS F> class ChunkedList;
  85 typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;
  86 
  87 DEBUG_ONLY(class ResourceMark;)
  88 
  89 class WorkerThread;
  90 
  91 // Class hierarchy
  92 // - Thread
  93 //   - NamedThread
  94 //     - VMThread
  95 //     - ConcurrentGCThread
  96 //     - WorkerThread
  97 //       - GangWorker
  98 //       - GCTaskThread
  99 //   - JavaThread
 100 //   - WatcherThread
 101 
 102 class Thread: public ThreadShadow {
 103   friend class VMStructs;
 104  private:
 105   // Exception handling
 106   // (Note: _pending_exception and friends are in ThreadShadow)
 107   //oop       _pending_exception;                // pending exception for current thread
 108   // const char* _exception_file;                   // file information for exception (debugging only)
 109   // int         _exception_line;                   // line information for exception (debugging only)
 110  protected:
 111   // Support for forcing alignment of thread objects for biased locking
 112   void*       _real_malloc_address;
 113  public:
 114   void* operator new(size_t size) throw() { return allocate(size, true); }
 115   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 116     return allocate(size, false); }
 117   void  operator delete(void* p);
 118 
 119  protected:
 120    static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 121  private:
 122 
 123   // ***************************************************************
 124   // Suspend and resume support
 125   // ***************************************************************
 126   //
 127   // VM suspend/resume no longer exists - it was once used for various
 128   // things including safepoints but was deprecated and finally removed
 129   // in Java 7. Because VM suspension was considered "internal" Java-level
 130   // suspension was considered "external", and this legacy naming scheme
 131   // remains.
 132   //
 133   // External suspend/resume requests come from JVM_SuspendThread,
 134   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 135   // ResumeThread. External
 136   // suspend requests cause _external_suspend to be set and external
 137   // resume requests cause _external_suspend to be cleared.
 138   // External suspend requests do not nest on top of other external
 139   // suspend requests. The higher level APIs reject suspend requests
 140   // for already suspended threads.
 141   //
 142   // The external_suspend
 143   // flag is checked by has_special_runtime_exit_condition() and java thread
 144   // will self-suspend when handle_special_runtime_exit_condition() is
 145   // called. Most uses of the _thread_blocked state in JavaThreads are
 146   // considered the same as being externally suspended; if the blocking
 147   // condition lifts, the JavaThread will self-suspend. Other places
 148   // where VM checks for external_suspend include:
 149   //   + mutex granting (do not enter monitors when thread is suspended)
 150   //   + state transitions from _thread_in_native
 151   //
 152   // In general, java_suspend() does not wait for an external suspend
 153   // request to complete. When it returns, the only guarantee is that
 154   // the _external_suspend field is true.
 155   //
 156   // wait_for_ext_suspend_completion() is used to wait for an external
 157   // suspend request to complete. External suspend requests are usually
 158   // followed by some other interface call that requires the thread to
 159   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 160   // the interface that requires quiescence, we give the JavaThread a
 161   // chance to self-suspend before we need it to be quiescent. This
 162   // improves overall suspend/query performance.
 163   //
 164   // _suspend_flags controls the behavior of java_ suspend/resume.
 165   // It must be set under the protection of SR_lock. Read from the flag is
 166   // OK without SR_lock as long as the value is only used as a hint.
 167   // (e.g., check _external_suspend first without lock and then recheck
 168   // inside SR_lock and finish the suspension)
 169   //
 170   // _suspend_flags is also overloaded for other "special conditions" so
 171   // that a single check indicates whether any special action is needed
 172   // eg. for async exceptions.
 173   // -------------------------------------------------------------------
 174   // Notes:
 175   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 176   // but we still update its value to keep other part of the system (mainly
 177   // JVMTI) happy. ThreadState is legacy code (see notes in
 178   // osThread.hpp).
 179   //
 180   // 2. It would be more natural if set_external_suspend() is private and
 181   // part of java_suspend(), but that probably would affect the suspend/query
 182   // performance. Need more investigation on this.
 183   //
 184 
 185   // suspend/resume lock: used for self-suspend
 186   Monitor* _SR_lock;
 187 
 188  protected:
 189   enum SuspendFlags {
 190     // NOTE: avoid using the sign-bit as cc generates different test code
 191     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 192 
 193     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 194     _ext_suspended          = 0x40000000U, // thread has self-suspended
 195     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 196 
 197     _has_async_exception    = 0x00000001U, // there is a pending async exception
 198     _critical_native_unlock = 0x00000002U  // Must call back to unlock JNI critical lock
 199   };
 200 
 201   // various suspension related flags - atomically updated
 202   // overloaded for async exception checking in check_special_condition_for_native_trans.
 203   volatile uint32_t _suspend_flags;
 204 
 205  private:
 206   int _num_nested_signal;
 207 
 208  public:
 209   void enter_signal_handler() { _num_nested_signal++; }
 210   void leave_signal_handler() { _num_nested_signal--; }
 211   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 212 
 213  private:
 214   // Debug tracing
 215   static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
 216 
 217   // Active_handles points to a block of handles
 218   JNIHandleBlock* _active_handles;
 219 
 220   // One-element thread local free list
 221   JNIHandleBlock* _free_handle_block;
 222 
 223   // Point to the last handle mark
 224   HandleMark* _last_handle_mark;
 225 
 226   // The parity of the last strong_roots iteration in which this thread was
 227   // claimed as a task.
 228   jint _oops_do_parity;
 229 
 230   public:
 231    void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 232    HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 233   private:
 234 
 235   // debug support for checking if code does allow safepoints or not
 236   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 237   // mutex, or blocking on an object synchronizer (Java locking).
 238   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 239   // If !allow_allocation(), then an assertion failure will happen during allocation
 240   // (Hence, !allow_safepoint() => !allow_allocation()).
 241   //
 242   // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
 243   //
 244   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 245   debug_only (int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 246 
 247   // Used by SkipGCALot class.
 248   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 249 
 250   friend class No_Alloc_Verifier;
 251   friend class No_Safepoint_Verifier;
 252   friend class Pause_No_Safepoint_Verifier;
 253   friend class ThreadLocalStorage;
 254   friend class GC_locker;
 255 
 256   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 257   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 258                                                 // the Java heap
 259 
 260   // Thread-local buffer used by MetadataOnStackMark.
 261   MetadataOnStackBuffer* _metadata_on_stack_buffer;
 262 
 263   TRACE_DATA _trace_data;                       // Thread-local data for tracing
 264 
 265   ThreadExt _ext;
 266 
 267   int   _vm_operation_started_count;            // VM_Operation support
 268   int   _vm_operation_completed_count;          // VM_Operation support
 269 
 270   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 271                                                 // is waiting to lock
 272   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 273 
 274   // ObjectMonitor on which this thread called Object.wait()
 275   ObjectMonitor* _current_waiting_monitor;
 276 
 277   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 278  public:
 279   ObjectMonitor* omFreeList;
 280   int omFreeCount;                              // length of omFreeList
 281   int omFreeProvision;                          // reload chunk size
 282   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 283   int omInUseCount;                             // length of omInUseList
 284 
 285 #ifdef ASSERT
 286  private:
 287   bool _visited_for_critical_count;
 288 
 289  public:
 290   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 291   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 292 #endif
 293 
 294  public:
 295   enum {
 296     is_definitely_current_thread = true
 297   };
 298 
 299   // Constructor
 300   Thread();
 301   virtual ~Thread();
 302 
 303   // initializtion
 304   void initialize_thread_local_storage();
 305 
 306   // thread entry point
 307   virtual void run();
 308 
 309   // Testers
 310   virtual bool is_VM_thread()       const            { return false; }
 311   virtual bool is_Java_thread()     const            { return false; }
 312   virtual bool is_Compiler_thread() const            { return false; }
 313   virtual bool is_hidden_from_external_view() const  { return false; }
 314   virtual bool is_jvmti_agent_thread() const         { return false; }
 315   // True iff the thread can perform GC operations at a safepoint.
 316   // Generally will be true only of VM thread and parallel GC WorkGang
 317   // threads.
 318   virtual bool is_GC_task_thread() const             { return false; }
 319   virtual bool is_Watcher_thread() const             { return false; }
 320   virtual bool is_ConcurrentGC_thread() const        { return false; }
 321   virtual bool is_Named_thread() const               { return false; }
 322   virtual bool is_Worker_thread() const              { return false; }
 323 
 324   // Casts
 325   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 326 
 327   virtual char* name() const { return (char*)"Unknown thread"; }
 328 
 329   // Returns the current thread
 330   static inline Thread* current();
 331 
 332   // Common thread operations
 333   static void set_priority(Thread* thread, ThreadPriority priority);
 334   static ThreadPriority get_priority(const Thread* const thread);
 335   static void start(Thread* thread);
 336   static void interrupt(Thread* thr);
 337   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 338 
 339   void set_native_thread_name(const char *name) {
 340     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 341     os::set_native_thread_name(name);
 342   }
 343 
 344   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 345   Monitor* SR_lock() const                       { return _SR_lock; }
 346 
 347   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 348 
 349   void set_suspend_flag(SuspendFlags f) {
 350     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 351     uint32_t flags;
 352     do {
 353       flags = _suspend_flags;
 354     }
 355     while (Atomic::cmpxchg((jint)(flags | f),
 356                            (volatile jint*)&_suspend_flags,
 357                            (jint)flags) != (jint)flags);
 358   }
 359   void clear_suspend_flag(SuspendFlags f) {
 360     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 361     uint32_t flags;
 362     do {
 363       flags = _suspend_flags;
 364     }
 365     while (Atomic::cmpxchg((jint)(flags & ~f),
 366                            (volatile jint*)&_suspend_flags,
 367                            (jint)flags) != (jint)flags);
 368   }
 369 
 370   void set_has_async_exception() {
 371     set_suspend_flag(_has_async_exception);
 372   }
 373   void clear_has_async_exception() {
 374     clear_suspend_flag(_has_async_exception);
 375   }
 376 
 377   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 378 
 379   void set_critical_native_unlock() {
 380     set_suspend_flag(_critical_native_unlock);
 381   }
 382   void clear_critical_native_unlock() {
 383     clear_suspend_flag(_critical_native_unlock);
 384   }
 385 
 386   // Support for Unhandled Oop detection
 387 #ifdef CHECK_UNHANDLED_OOPS
 388  private:
 389   UnhandledOops* _unhandled_oops;
 390  public:
 391   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 392   // Mark oop safe for gc.  It may be stack allocated but won't move.
 393   void allow_unhandled_oop(oop *op) {
 394     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 395   }
 396   // Clear oops at safepoint so crashes point to unhandled oop violator
 397   void clear_unhandled_oops() {
 398     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 399   }
 400 #endif // CHECK_UNHANDLED_OOPS
 401 
 402 #ifndef PRODUCT
 403   bool skip_gcalot()           { return _skip_gcalot; }
 404   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 405 #endif
 406 
 407  public:
 408   // Installs a pending exception to be inserted later
 409   static void send_async_exception(oop thread_oop, oop java_throwable);
 410 
 411   // Resource area
 412   ResourceArea* resource_area() const            { return _resource_area; }
 413   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 414 
 415   OSThread* osthread() const                     { return _osthread;   }
 416   void set_osthread(OSThread* thread)            { _osthread = thread; }
 417 
 418   // JNI handle support
 419   JNIHandleBlock* active_handles() const         { return _active_handles; }
 420   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 421   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 422   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 423 
 424   // Internal handle support
 425   HandleArea* handle_area() const                { return _handle_area; }
 426   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 427 
 428   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 429   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 430 
 431   // Thread-Local Allocation Buffer (TLAB) support
 432   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 433   void initialize_tlab() {
 434     if (UseTLAB) {
 435       tlab().initialize();
 436     }
 437   }
 438 
 439   jlong allocated_bytes()               { return _allocated_bytes; }
 440   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 441   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 442   inline jlong cooked_allocated_bytes();
 443 
 444   TRACE_DATA* trace_data()              { return &_trace_data; }
 445 
 446   const ThreadExt& ext() const          { return _ext; }
 447   ThreadExt& ext()                      { return _ext; }
 448 
 449   // VM operation support
 450   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 451   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 452   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 453 
 454   // For tracking the heavyweight monitor the thread is pending on.
 455   ObjectMonitor* current_pending_monitor() {
 456     return _current_pending_monitor;
 457   }
 458   void set_current_pending_monitor(ObjectMonitor* monitor) {
 459     _current_pending_monitor = monitor;
 460   }
 461   void set_current_pending_monitor_is_from_java(bool from_java) {
 462     _current_pending_monitor_is_from_java = from_java;
 463   }
 464   bool current_pending_monitor_is_from_java() {
 465     return _current_pending_monitor_is_from_java;
 466   }
 467 
 468   // For tracking the ObjectMonitor on which this thread called Object.wait()
 469   ObjectMonitor* current_waiting_monitor() {
 470     return _current_waiting_monitor;
 471   }
 472   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 473     _current_waiting_monitor = monitor;
 474   }
 475 
 476   // GC support
 477   // Apply "f->do_oop" to all root oops in "this".
 478   // Apply "cld_f->do_cld" to CLDs that are otherwise not kept alive.
 479   //   Used by JavaThread::oops_do.
 480   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 481   virtual void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
 482 
 483   // Handles the parallel case for the method below.
 484 private:
 485   bool claim_oops_do_par_case(int collection_parity);
 486 public:
 487   // Requires that "collection_parity" is that of the current roots
 488   // iteration.  If "is_par" is false, sets the parity of "this" to
 489   // "collection_parity", and returns "true".  If "is_par" is true,
 490   // uses an atomic instruction to set the current threads parity to
 491   // "collection_parity", if it is not already.  Returns "true" iff the
 492   // calling thread does the update, this indicates that the calling thread
 493   // has claimed the thread's stack as a root groop in the current
 494   // collection.
 495   bool claim_oops_do(bool is_par, int collection_parity) {
 496     if (!is_par) {
 497       _oops_do_parity = collection_parity;
 498       return true;
 499     } else {
 500       return claim_oops_do_par_case(collection_parity);
 501     }
 502   }
 503 
 504   // Sweeper support
 505   void nmethods_do(CodeBlobClosure* cf);
 506 
 507   // jvmtiRedefineClasses support
 508   void metadata_do(void f(Metadata*));
 509 
 510   // Used by fast lock support
 511   virtual bool is_lock_owned(address adr) const;
 512 
 513   // Check if address is in the stack of the thread (not just for locks).
 514   // Warning: the method can only be used on the running thread
 515   bool is_in_stack(address adr) const;
 516   // Check if address is in the usable part of the stack (excludes protected
 517   // guard pages)
 518   bool is_in_usable_stack(address adr) const;
 519 
 520   // Sets this thread as starting thread. Returns failure if thread
 521   // creation fails due to lack of memory, too many threads etc.
 522   bool set_as_starting_thread();
 523 
 524   void set_metadata_on_stack_buffer(MetadataOnStackBuffer* buffer) { _metadata_on_stack_buffer = buffer; }
 525   MetadataOnStackBuffer* metadata_on_stack_buffer() const          { return _metadata_on_stack_buffer; }
 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   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 535 
 536   // Thread local handle area for allocation of handles within the VM
 537   HandleArea* _handle_area;
 538   GrowableArray<Metadata*>* _metadata_handles;
 539 
 540   // Support for stack overflow handling, get_thread, etc.
 541   address          _stack_base;
 542   size_t           _stack_size;
 543   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 544   int              _lgrp_id;
 545 
 546  public:
 547   // Stack overflow support
 548   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 549 
 550   void    set_stack_base(address base) { _stack_base = base; }
 551   size_t  stack_size() const           { return _stack_size; }
 552   void    set_stack_size(size_t size)  { _stack_size = size; }
 553   void    record_stack_base_and_size();
 554 
 555   bool    on_local_stack(address adr) const {
 556     /* QQQ this has knowledge of direction, ought to be a stack method */
 557     return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
 558   }
 559 
 560   uintptr_t self_raw_id()                    { return _self_raw_id; }
 561   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 562 
 563   int     lgrp_id() const        { return _lgrp_id; }
 564   void    set_lgrp_id(int value) { _lgrp_id = value; }
 565 
 566   // Printing
 567   void print_on(outputStream* st) const;
 568   void print() const { print_on(tty); }
 569   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 570 
 571   // Debug-only code
 572 #ifdef ASSERT
 573  private:
 574   // Deadlock detection support for Mutex locks. List of locks own by thread.
 575   Monitor* _owned_locks;
 576   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 577   // thus the friendship
 578   friend class Mutex;
 579   friend class Monitor;
 580 
 581  public:
 582   void print_owned_locks_on(outputStream* st) const;
 583   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 584   Monitor* owned_locks() const                   { return _owned_locks;          }
 585   bool owns_locks() const                        { return owned_locks() != NULL; }
 586   bool owns_locks_but_compiled_lock() const;
 587 
 588   // Deadlock detection
 589   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 590   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 591   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 592 #endif
 593 
 594   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 595 
 596  private:
 597   volatile int _jvmti_env_iteration_count;
 598 
 599  public:
 600   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 601   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 602   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 603 
 604   // Code generation
 605   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file   ); }
 606   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line   ); }
 607   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles   ); }
 608 
 609   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base ); }
 610   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size ); }
 611 
 612 #define TLAB_FIELD_OFFSET(name) \
 613   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 614 
 615   TLAB_FIELD_OFFSET(start)
 616   TLAB_FIELD_OFFSET(end)
 617   TLAB_FIELD_OFFSET(top)
 618   TLAB_FIELD_OFFSET(pf_top)
 619   TLAB_FIELD_OFFSET(size)                   // desired_size
 620   TLAB_FIELD_OFFSET(refill_waste_limit)
 621   TLAB_FIELD_OFFSET(number_of_refills)
 622   TLAB_FIELD_OFFSET(fast_refill_waste)
 623   TLAB_FIELD_OFFSET(slow_allocations)
 624 
 625 #undef TLAB_FIELD_OFFSET
 626 
 627   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes ); }
 628 
 629  public:
 630   volatile intptr_t _Stalled ;
 631   volatile int _TypeTag ;
 632   ParkEvent * _ParkEvent ;                     // for synchronized()
 633   ParkEvent * _SleepEvent ;                    // for Thread.sleep
 634   ParkEvent * _MutexEvent ;                    // for native internal Mutex/Monitor
 635   ParkEvent * _MuxEvent ;                      // for low-level muxAcquire-muxRelease
 636   int NativeSyncRecursion ;                    // diagnostic
 637 
 638   volatile int _OnTrap ;                       // Resume-at IP delta
 639   jint _hashStateW ;                           // Marsaglia Shift-XOR thread-local RNG
 640   jint _hashStateX ;                           // thread-specific hashCode generator state
 641   jint _hashStateY ;
 642   jint _hashStateZ ;
 643   void * _schedctl ;
 644 
 645 
 646   volatile jint rng [4] ;                      // RNG for spin loop
 647 
 648   // Low-level leaf-lock primitives used to implement synchronization
 649   // and native monitor-mutex infrastructure.
 650   // Not for general synchronization use.
 651   static void SpinAcquire (volatile int * Lock, const char * Name) ;
 652   static void SpinRelease (volatile int * Lock) ;
 653   static void muxAcquire  (volatile intptr_t * Lock, const char * Name) ;
 654   static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
 655   static void muxRelease  (volatile intptr_t * Lock) ;
 656 };
 657 
 658 // Inline implementation of Thread::current()
 659 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
 660 // startup.
 661 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
 662 // period.   This is inlined in thread_<os_family>.inline.hpp.
 663 
 664 inline Thread* Thread::current() {
 665 #ifdef ASSERT
 666 // This function is very high traffic. Define PARANOID to enable expensive
 667 // asserts.
 668 #ifdef PARANOID
 669   // Signal handler should call ThreadLocalStorage::get_thread_slow()
 670   Thread* t = ThreadLocalStorage::get_thread_slow();
 671   assert(t != NULL && !t->is_inside_signal_handler(),
 672          "Don't use Thread::current() inside signal handler");
 673 #endif
 674 #endif
 675   Thread* thread = ThreadLocalStorage::thread();
 676   assert(thread != NULL, "just checking");
 677   return thread;
 678 }
 679 
 680 // Name support for threads.  non-JavaThread subclasses with multiple
 681 // uniquely named instances should derive from this.
 682 class NamedThread: public Thread {
 683   friend class VMStructs;
 684   enum {
 685     max_name_len = 64
 686   };
 687  private:
 688   char* _name;
 689   // log JavaThread being processed by oops_do
 690   JavaThread* _processed_thread;
 691 
 692  public:
 693   NamedThread();
 694   ~NamedThread();
 695   // May only be called once per thread.
 696   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 697   virtual bool is_Named_thread() const { return true; }
 698   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 699   JavaThread *processed_thread() { return _processed_thread; }
 700   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 701 };
 702 
 703 // Worker threads are named and have an id of an assigned work.
 704 class WorkerThread: public NamedThread {
 705 private:
 706   uint _id;
 707 public:
 708   WorkerThread() : _id(0)               { }
 709   virtual bool is_Worker_thread() const { return true; }
 710 
 711   virtual WorkerThread* as_Worker_thread() const {
 712     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 713     return (WorkerThread*) this;
 714   }
 715 
 716   void set_id(uint work_id)             { _id = work_id; }
 717   uint id() const                       { return _id; }
 718 };
 719 
 720 // A single WatcherThread is used for simulating timer interrupts.
 721 class WatcherThread: public Thread {
 722   friend class VMStructs;
 723  public:
 724   virtual void run();
 725 
 726  private:
 727   static WatcherThread* _watcher_thread;
 728 
 729   static bool _startable;
 730   volatile static bool _should_terminate; // updated without holding lock
 731 
 732   os::WatcherThreadCrashProtection* _crash_protection;
 733  public:
 734   enum SomeConstants {
 735     delay_interval = 10                          // interrupt delay in milliseconds
 736   };
 737 
 738   // Constructor
 739   WatcherThread();
 740 
 741   // Tester
 742   bool is_Watcher_thread() const                 { return true; }
 743 
 744   // Printing
 745   char* name() const { return (char*)"VM Periodic Task Thread"; }
 746   void print_on(outputStream* st) const;
 747   void print() const { print_on(tty); }
 748   void unpark();
 749 
 750   // Returns the single instance of WatcherThread
 751   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 752 
 753   // Create and start the single instance of WatcherThread, or stop it on shutdown
 754   static void start();
 755   static void stop();
 756   // Only allow start once the VM is sufficiently initialized
 757   // Otherwise the first task to enroll will trigger the start
 758   static void make_startable();
 759 
 760   void set_crash_protection(os::WatcherThreadCrashProtection* crash_protection) {
 761     assert(Thread::current()->is_Watcher_thread(), "Can only be set by WatcherThread");
 762     _crash_protection = crash_protection;
 763   }
 764 
 765   bool has_crash_protection() const { return _crash_protection != NULL; }
 766   os::WatcherThreadCrashProtection* crash_protection() const { return _crash_protection; }
 767 
 768  private:
 769   int sleep() const;
 770 };
 771 
 772 
 773 class CompilerThread;
 774 
 775 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 776 
 777 class JavaThread: public Thread {
 778   friend class VMStructs;
 779  private:
 780   JavaThread*    _next;                          // The next thread in the Threads list
 781   oop            _threadObj;                     // The Java level thread object
 782 
 783 #ifdef ASSERT
 784  private:
 785   int _java_call_counter;
 786 
 787  public:
 788   int  java_call_counter()                       { return _java_call_counter; }
 789   void inc_java_call_counter()                   { _java_call_counter++; }
 790   void dec_java_call_counter() {
 791     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 792     _java_call_counter--;
 793   }
 794  private:  // restore original namespace restriction
 795 #endif  // ifdef ASSERT
 796 
 797 #ifndef PRODUCT
 798  public:
 799   enum {
 800     jump_ring_buffer_size = 16
 801   };
 802  private:  // restore original namespace restriction
 803 #endif
 804 
 805   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 806 
 807   ThreadFunction _entry_point;
 808 
 809   JNIEnv        _jni_environment;
 810 
 811   // Deopt support
 812   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 813 
 814   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 815                                                  // transition out of native
 816   nmethod*       _deopt_nmethod;                 // nmethod that is currently being deoptimized
 817   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 818   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 819   // Because deoptimization is lazy we must save jvmti requests to set locals
 820   // in compiled frames until we deoptimize and we have an interpreter frame.
 821   // This holds the pointer to array (yeah like there might be more than one) of
 822   // description of compiled vframes that have locals that need to be updated.
 823   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 824 
 825   // Handshake value for fixing 6243940. We need a place for the i2c
 826   // adapter to store the callee Method*. This value is NEVER live
 827   // across a gc point so it does NOT have to be gc'd
 828   // The handshake is open ended since we can't be certain that it will
 829   // be NULLed. This is because we rarely ever see the race and end up
 830   // in handle_wrong_method which is the backend of the handshake. See
 831   // code in i2c adapters and handle_wrong_method.
 832 
 833   Method*       _callee_target;
 834 
 835   // Used to pass back results to the interpreter or generated code running Java code.
 836   oop           _vm_result;    // oop result is GC-preserved
 837   Metadata*     _vm_result_2;  // non-oop result
 838 
 839   // See ReduceInitialCardMarks: this holds the precise space interval of
 840   // the most recent slow path allocation for which compiled code has
 841   // elided card-marks for performance along the fast-path.
 842   MemRegion     _deferred_card_mark;
 843 
 844   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 845                                                  // allocated during deoptimization
 846                                                  // and by JNI_MonitorEnter/Exit
 847 
 848   // Async. requests support
 849   enum AsyncRequests {
 850     _no_async_condition = 0,
 851     _async_exception,
 852     _async_unsafe_access_error
 853   };
 854   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 855   oop           _pending_async_exception;
 856 
 857   // Safepoint support
 858  public:                                         // Expose _thread_state for SafeFetchInt()
 859   volatile JavaThreadState _thread_state;
 860  private:
 861   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 862   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 863 
 864   // JavaThread termination support
 865   enum TerminatedTypes {
 866     _not_terminated = 0xDEAD - 2,
 867     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 868     _thread_terminated,                          // JavaThread is removed from thread list
 869     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 870                                                  // only VM_Exit can set _vm_exited
 871   };
 872 
 873   // In general a JavaThread's _terminated field transitions as follows:
 874   //
 875   //   _not_terminated => _thread_exiting => _thread_terminated
 876   //
 877   // _vm_exited is a special value to cover the case of a JavaThread
 878   // executing native code after the VM itself is terminated.
 879   volatile TerminatedTypes _terminated;
 880   // suspend/resume support
 881   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 882   jint                  _in_deopt_handler;       // count of deoptimization
 883                                                  // handlers thread is in
 884   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 885   bool                  _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
 886                                                  // never locked) when throwing an exception. Used by interpreter only.
 887 
 888   // JNI attach states:
 889   enum JNIAttachStates {
 890     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 891     _attaching_via_jni,          // thread is attaching via JNI
 892     _attached_via_jni            // thread has attached via JNI
 893   };
 894 
 895   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 896   // A native thread that is attaching via JNI starts with a value
 897   // of _attaching_via_jni and transitions to _attached_via_jni.
 898   volatile JNIAttachStates _jni_attach_state;
 899 
 900  public:
 901   // State of the stack guard pages for this thread.
 902   enum StackGuardState {
 903     stack_guard_unused,         // not needed
 904     stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
 905     stack_guard_enabled         // enabled
 906   };
 907 
 908  private:
 909 
 910   StackGuardState  _stack_guard_state;
 911 
 912   // Precompute the limit of the stack as used in stack overflow checks.
 913   // We load it from here to simplify the stack overflow check in assembly.
 914   address          _stack_overflow_limit;
 915 
 916   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 917   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 918   // code)
 919   volatile oop     _exception_oop;               // Exception thrown in compiled code
 920   volatile address _exception_pc;                // PC where exception happened
 921   volatile address _exception_handler_pc;        // PC for handler of exception
 922   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 923 
 924   // support for JNI critical regions
 925   jint    _jni_active_critical;                  // count of entries into JNI critical region
 926 
 927   // Checked JNI: function name requires exception check
 928   char* _pending_jni_exception_check_fn;
 929 
 930   // For deadlock detection.
 931   int _depth_first_number;
 932 
 933   // JVMTI PopFrame support
 934   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 935   int _popframe_condition;
 936 
 937   // If reallocation of scalar replaced objects fails, we throw OOM
 938   // and during exception propagation, pop the top
 939   // _frames_to_pop_failed_realloc frames, the ones that reference
 940   // failed reallocations.
 941   int _frames_to_pop_failed_realloc;
 942 
 943 #ifndef PRODUCT
 944   int _jmp_ring_index;
 945   struct {
 946       // We use intptr_t instead of address so debugger doesn't try and display strings
 947       intptr_t _target;
 948       intptr_t _instruction;
 949       const char*  _file;
 950       int _line;
 951   }   _jmp_ring[ jump_ring_buffer_size ];
 952 #endif /* PRODUCT */
 953 
 954 #if INCLUDE_ALL_GCS
 955   // Support for G1 barriers
 956 
 957   ObjPtrQueue _satb_mark_queue;          // Thread-local log for SATB barrier.
 958   // Set of all such queues.
 959   static SATBMarkQueueSet _satb_mark_queue_set;
 960 
 961   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.
 962   // Set of all such queues.
 963   static DirtyCardQueueSet _dirty_card_queue_set;
 964 
 965   void flush_barrier_queues();
 966 #endif // INCLUDE_ALL_GCS
 967 
 968   friend class VMThread;
 969   friend class ThreadWaitTransition;
 970   friend class VM_Exit;
 971 
 972   void initialize();                             // Initialized the instance variables
 973 
 974  public:
 975   // Constructor
 976   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
 977   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 978   ~JavaThread();
 979 
 980 #ifdef ASSERT
 981   // verify this JavaThread hasn't be published in the Threads::list yet
 982   void verify_not_published();
 983 #endif
 984 
 985   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 986   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 987     _jni_environment.functions = functionTable;
 988   }
 989   struct JNINativeInterface_* get_jni_functions() {
 990     return (struct JNINativeInterface_ *)_jni_environment.functions;
 991   }
 992 
 993   // This function is called at thread creation to allow
 994   // platform specific thread variables to be initialized.
 995   void cache_global_variables();
 996 
 997   // Executes Shutdown.shutdown()
 998   void invoke_shutdown_hooks();
 999 
1000   // Cleanup on thread exit
1001   enum ExitType {
1002     normal_exit,
1003     jni_detach
1004   };
1005   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1006 
1007   void cleanup_failed_attach_current_thread();
1008 
1009   // Testers
1010   virtual bool is_Java_thread() const            { return true;  }
1011 
1012   // Thread chain operations
1013   JavaThread* next() const                       { return _next; }
1014   void set_next(JavaThread* p)                   { _next = p; }
1015 
1016   // Thread oop. threadObj() can be NULL for initial JavaThread
1017   // (or for threads attached via JNI)
1018   oop threadObj() const                          { return _threadObj; }
1019   void set_threadObj(oop p)                      { _threadObj = p; }
1020 
1021   ThreadPriority java_priority() const;          // Read from threadObj()
1022 
1023   // Prepare thread and add to priority queue.  If a priority is
1024   // not specified, use the priority of the thread object. Threads_lock
1025   // must be held while this function is called.
1026   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1027   void prepare_ext();
1028 
1029   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1030   address saved_exception_pc()                   { return _saved_exception_pc; }
1031 
1032 
1033   ThreadFunction entry_point() const             { return _entry_point; }
1034 
1035   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1036   void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
1037 
1038   // Last frame anchor routines
1039 
1040   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1041 
1042   // last_Java_sp
1043   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1044   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1045 
1046   // last_Java_pc
1047 
1048   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1049 
1050   // Safepoint support
1051 #ifndef PPC64
1052   JavaThreadState thread_state() const           { return _thread_state; }
1053   void set_thread_state(JavaThreadState s)       { _thread_state = s;    }
1054 #else
1055   // Use membars when accessing volatile _thread_state. See
1056   // Threads::create_vm() for size checks.
1057   inline JavaThreadState thread_state() const;
1058   inline void set_thread_state(JavaThreadState s);
1059 #endif
1060   ThreadSafepointState *safepoint_state() const  { return _safepoint_state; }
1061   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1062   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1063 
1064   // thread has called JavaThread::exit() or is terminated
1065   bool is_exiting()                              { return _terminated == _thread_exiting || is_terminated(); }
1066   // thread is terminated (no longer on the threads list); we compare
1067   // against the two non-terminated values so that a freed JavaThread
1068   // will also be considered terminated.
1069   bool is_terminated()                           { return _terminated != _not_terminated && _terminated != _thread_exiting; }
1070   void set_terminated(TerminatedTypes t)         { _terminated = t; }
1071   // special for Threads::remove() which is static:
1072   void set_terminated_value()                    { _terminated = _thread_terminated; }
1073   void block_if_vm_exited();
1074 
1075   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1076   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1077 
1078   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1079   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1080 
1081   // Suspend/resume support for JavaThread
1082  private:
1083   void set_ext_suspended()       { set_suspend_flag (_ext_suspended);  }
1084   void clear_ext_suspended()     { clear_suspend_flag(_ext_suspended); }
1085 
1086  public:
1087   void java_suspend();
1088   void java_resume();
1089   int  java_suspend_self();
1090 
1091   void check_and_wait_while_suspended() {
1092     assert(JavaThread::current() == this, "sanity check");
1093 
1094     bool do_self_suspend;
1095     do {
1096       // were we externally suspended while we were waiting?
1097       do_self_suspend = handle_special_suspend_equivalent_condition();
1098       if (do_self_suspend) {
1099         // don't surprise the thread that suspended us by returning
1100         java_suspend_self();
1101         set_suspend_equivalent();
1102       }
1103     } while (do_self_suspend);
1104   }
1105   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1106   // Check for async exception in addition to safepoint and suspend request.
1107   static void check_special_condition_for_native_trans(JavaThread *thread);
1108 
1109   // Same as check_special_condition_for_native_trans but finishes the
1110   // transition into thread_in_Java mode so that it can potentially
1111   // block.
1112   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1113 
1114   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1115   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1116     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1117     // Warning: is_ext_suspend_completed() may temporarily drop the
1118     // SR_lock to allow the thread to reach a stable thread state if
1119     // it is currently in a transient thread state.
1120     return is_ext_suspend_completed(false /*!called_by_wait */,
1121                                     SuspendRetryDelay, bits);
1122   }
1123 
1124   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1125   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1126   // passed as the count and delay parameters. Experiments with specific
1127   // calls to wait_for_ext_suspend_completion() can be done by passing
1128   // other values in the code. Experiments with all calls can be done
1129   // via the appropriate -XX options.
1130   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1131 
1132   void set_external_suspend()     { set_suspend_flag  (_external_suspend); }
1133   void clear_external_suspend()   { clear_suspend_flag(_external_suspend); }
1134 
1135   void set_deopt_suspend()        { set_suspend_flag  (_deopt_suspend); }
1136   void clear_deopt_suspend()      { clear_suspend_flag(_deopt_suspend); }
1137   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1138 
1139   bool is_external_suspend() const {
1140     return (_suspend_flags & _external_suspend) != 0;
1141   }
1142   // Whenever a thread transitions from native to vm/java it must suspend
1143   // if external|deopt suspend is present.
1144   bool is_suspend_after_native() const {
1145     return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
1146   }
1147 
1148   // external suspend request is completed
1149   bool is_ext_suspended() const {
1150     return (_suspend_flags & _ext_suspended) != 0;
1151   }
1152 
1153   bool is_external_suspend_with_lock() const {
1154     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1155     return is_external_suspend();
1156   }
1157 
1158   // Special method to handle a pending external suspend request
1159   // when a suspend equivalent condition lifts.
1160   bool handle_special_suspend_equivalent_condition() {
1161     assert(is_suspend_equivalent(),
1162       "should only be called in a suspend equivalence condition");
1163     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1164     bool ret = is_external_suspend();
1165     if (!ret) {
1166       // not about to self-suspend so clear suspend equivalence
1167       clear_suspend_equivalent();
1168     }
1169     // implied else:
1170     // We have a pending external suspend request so we leave the
1171     // suspend_equivalent flag set until java_suspend_self() sets
1172     // the ext_suspended flag and clears the suspend_equivalent
1173     // flag. This insures that wait_for_ext_suspend_completion()
1174     // will return consistent values.
1175     return ret;
1176   }
1177 
1178   // utility methods to see if we are doing some kind of suspension
1179   bool is_being_ext_suspended() const            {
1180     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1181     return is_ext_suspended() || is_external_suspend();
1182   }
1183 
1184   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1185 
1186   void set_suspend_equivalent()                  { _suspend_equivalent = true; };
1187   void clear_suspend_equivalent()                { _suspend_equivalent = false; };
1188 
1189   // Thread.stop support
1190   void send_thread_stop(oop throwable);
1191   AsyncRequests clear_special_runtime_exit_condition() {
1192     AsyncRequests x = _special_runtime_exit_condition;
1193     _special_runtime_exit_condition = _no_async_condition;
1194     return x;
1195   }
1196 
1197   // Are any async conditions present?
1198   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1199 
1200   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1201 
1202   // these next two are also used for self-suspension and async exception support
1203   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1204 
1205   // Return true if JavaThread has an asynchronous condition or
1206   // if external suspension is requested.
1207   bool has_special_runtime_exit_condition() {
1208     // We call is_external_suspend() last since external suspend should
1209     // be less common. Because we don't use is_external_suspend_with_lock
1210     // it is possible that we won't see an asynchronous external suspend
1211     // request that has just gotten started, i.e., SR_lock grabbed but
1212     // _external_suspend field change either not made yet or not visible
1213     // yet. However, this is okay because the request is asynchronous and
1214     // we will see the new flag value the next time through. It's also
1215     // possible that the external suspend request is dropped after
1216     // we have checked is_external_suspend(), we will recheck its value
1217     // under SR_lock in java_suspend_self().
1218     return (_special_runtime_exit_condition != _no_async_condition) ||
1219             is_external_suspend() || is_deopt_suspend();
1220   }
1221 
1222   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1223 
1224   void set_pending_async_exception(oop e) {
1225     _pending_async_exception = e;
1226     _special_runtime_exit_condition = _async_exception;
1227     set_has_async_exception();
1228   }
1229 
1230   // Fast-locking support
1231   bool is_lock_owned(address adr) const;
1232 
1233   // Accessors for vframe array top
1234   // The linked list of vframe arrays are sorted on sp. This means when we
1235   // unpack the head must contain the vframe array to unpack.
1236   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1237   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1238 
1239   // Side structure for defering update of java frame locals until deopt occurs
1240   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1241   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1242 
1243   // These only really exist to make debugging deopt problems simpler
1244 
1245   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1246   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1247 
1248   // The special resourceMark used during deoptimization
1249 
1250   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1251   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1252 
1253   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1254   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1255   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1256 
1257   void set_deopt_nmethod(nmethod* nm)            { _deopt_nmethod = nm;   }
1258   nmethod* deopt_nmethod()                       { return _deopt_nmethod; }
1259 
1260   Method*    callee_target() const               { return _callee_target; }
1261   void set_callee_target  (Method* x)          { _callee_target   = x; }
1262 
1263   // Oop results of vm runtime calls
1264   oop  vm_result() const                         { return _vm_result; }
1265   void set_vm_result  (oop x)                    { _vm_result   = x; }
1266 
1267   Metadata*    vm_result_2() const               { return _vm_result_2; }
1268   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1269 
1270   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1271   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1272 
1273   // Exception handling for compiled methods
1274   oop      exception_oop() const                 { return _exception_oop; }
1275   address  exception_pc() const                  { return _exception_pc; }
1276   address  exception_handler_pc() const          { return _exception_handler_pc; }
1277   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1278 
1279   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1280   void set_exception_pc(address a)               { _exception_pc = a; }
1281   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1282   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1283 
1284   void clear_exception_oop_and_pc() {
1285     set_exception_oop(NULL);
1286     set_exception_pc(NULL);
1287   }
1288 
1289   // Stack overflow support
1290   inline size_t stack_available(address cur_sp);
1291   address stack_yellow_zone_base()
1292     { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
1293   size_t  stack_yellow_zone_size()
1294     { return StackYellowPages * os::vm_page_size(); }
1295   address stack_red_zone_base()
1296     { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
1297   size_t stack_red_zone_size()
1298     { return StackRedPages * os::vm_page_size(); }
1299   bool in_stack_yellow_zone(address a)
1300     { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
1301   bool in_stack_red_zone(address a)
1302     { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
1303 
1304   void create_stack_guard_pages();
1305   void remove_stack_guard_pages();
1306 
1307   void enable_stack_yellow_zone();
1308   void disable_stack_yellow_zone();
1309   void enable_stack_red_zone();
1310   void disable_stack_red_zone();
1311 
1312   inline bool stack_guard_zone_unused();
1313   inline bool stack_yellow_zone_disabled();
1314   inline bool stack_yellow_zone_enabled();
1315 
1316   // Attempt to reguard the stack after a stack overflow may have occurred.
1317   // Returns true if (a) guard pages are not needed on this thread, (b) the
1318   // pages are already guarded, or (c) the pages were successfully reguarded.
1319   // Returns false if there is not enough stack space to reguard the pages, in
1320   // which case the caller should unwind a frame and try again.  The argument
1321   // should be the caller's (approximate) sp.
1322   bool reguard_stack(address cur_sp);
1323   // Similar to above but see if current stackpoint is out of the guard area
1324   // and reguard if possible.
1325   bool reguard_stack(void);
1326 
1327   address stack_overflow_limit() { return _stack_overflow_limit; }
1328   void set_stack_overflow_limit() {
1329     _stack_overflow_limit = _stack_base - _stack_size +
1330                             ((StackShadowPages +
1331                               StackYellowPages +
1332                               StackRedPages) * os::vm_page_size());
1333   }
1334 
1335   // Misc. accessors/mutators
1336   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1337   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1338   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1339 
1340 #ifndef PRODUCT
1341   void record_jump(address target, address instr, const char* file, int line);
1342 #endif /* PRODUCT */
1343 
1344   // For assembly stub generation
1345   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj           ); }
1346 #ifndef PRODUCT
1347   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index      ); }
1348   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring            ); }
1349 #endif /* PRODUCT */
1350   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment     ); }
1351   static ByteSize last_Java_sp_offset()          {
1352     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1353   }
1354   static ByteSize last_Java_pc_offset()          {
1355     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1356   }
1357   static ByteSize frame_anchor_offset()          {
1358     return byte_offset_of(JavaThread, _anchor);
1359   }
1360   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target       ); }
1361   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result           ); }
1362   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2         ); }
1363   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state        ); }
1364   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
1365   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
1366   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
1367   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
1368   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1369   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1370   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1371   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
1372   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
1373 
1374   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1375   static ByteSize should_post_on_exceptions_flag_offset() {
1376     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1377   }
1378 
1379 #if INCLUDE_ALL_GCS
1380   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
1381   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
1382 #endif // INCLUDE_ALL_GCS
1383 
1384   // Returns the jni environment for this thread
1385   JNIEnv* jni_environment()                      { return &_jni_environment; }
1386 
1387   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1388     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1389     // Only return NULL if thread is off the thread list; starting to
1390     // exit should not return NULL.
1391     if (thread_from_jni_env->is_terminated()) {
1392        thread_from_jni_env->block_if_vm_exited();
1393        return NULL;
1394     } else {
1395        return thread_from_jni_env;
1396     }
1397   }
1398 
1399   // JNI critical regions. These can nest.
1400   bool in_critical()    { return _jni_active_critical > 0; }
1401   bool in_last_critical()  { return _jni_active_critical == 1; }
1402   void enter_critical() { assert(Thread::current() == this ||
1403                                  Thread::current()->is_VM_thread() && SafepointSynchronize::is_synchronizing(),
1404                                  "this must be current thread or synchronizing");
1405                           _jni_active_critical++; }
1406   void exit_critical()  { assert(Thread::current() == this,
1407                                  "this must be current thread");
1408                           _jni_active_critical--;
1409                           assert(_jni_active_critical >= 0,
1410                                  "JNI critical nesting problem?"); }
1411 
1412   // Checked JNI, is the programmer required to check for exceptions, specify which function name
1413   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1414   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1415   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1416   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1417 
1418   // For deadlock detection
1419   int depth_first_number() { return _depth_first_number; }
1420   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1421 
1422  private:
1423   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1424 
1425  public:
1426   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1427   void add_monitor_chunk(MonitorChunk* chunk);
1428   void remove_monitor_chunk(MonitorChunk* chunk);
1429   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1430   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1431   void dec_in_deopt_handler()                    {
1432     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1433     if (_in_deopt_handler > 0) { // robustness
1434       _in_deopt_handler--;
1435     }
1436   }
1437 
1438  private:
1439   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1440 
1441  public:
1442 
1443   // Frame iteration; calls the function f for all frames on the stack
1444   void frames_do(void f(frame*, const RegisterMap*));
1445 
1446   // Memory operations
1447   void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1448 
1449   // Sweeper operations
1450   void nmethods_do(CodeBlobClosure* cf);
1451 
1452   // RedefineClasses Support
1453   void metadata_do(void f(Metadata*));
1454 
1455   // Memory management operations
1456   void gc_epilogue();
1457   void gc_prologue();
1458 
1459   // Misc. operations
1460   char* name() const { return (char*)get_thread_name(); }
1461   void print_on(outputStream* st) const;
1462   void print() const { print_on(tty); }
1463   void print_value();
1464   void print_thread_state_on(outputStream* ) const      PRODUCT_RETURN;
1465   void print_thread_state() const                       PRODUCT_RETURN;
1466   void print_on_error(outputStream* st, char* buf, int buflen) const;
1467   void verify();
1468   const char* get_thread_name() const;
1469 private:
1470   // factor out low-level mechanics for use in both normal and error cases
1471   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1472 public:
1473   const char* get_threadgroup_name() const;
1474   const char* get_parent_name() const;
1475 
1476   // Accessing frames
1477   frame last_frame() {
1478     _anchor.make_walkable(this);
1479     return pd_last_frame();
1480   }
1481   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1482 
1483   // Returns method at 'depth' java or native frames down the stack
1484   // Used for security checks
1485   Klass* security_get_caller_class(int depth);
1486 
1487   // Print stack trace in external format
1488   void print_stack_on(outputStream* st);
1489   void print_stack() { print_stack_on(tty); }
1490 
1491   // Print stack traces in various internal formats
1492   void trace_stack()                             PRODUCT_RETURN;
1493   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1494   void trace_frames()                            PRODUCT_RETURN;
1495   void trace_oops()                              PRODUCT_RETURN;
1496 
1497   // Print an annotated view of the stack frames
1498   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1499   void validate_frame_layout() {
1500     print_frame_layout(0, true);
1501   }
1502 
1503   // Returns the number of stack frames on the stack
1504   int depth() const;
1505 
1506   // Function for testing deoptimization
1507   void deoptimize();
1508   void make_zombies();
1509 
1510   void deoptimized_wrt_marked_nmethods();
1511 
1512   // Profiling operation (see fprofile.cpp)
1513  public:
1514    bool profile_last_Java_frame(frame* fr);
1515 
1516  private:
1517    ThreadProfiler* _thread_profiler;
1518  private:
1519    friend class FlatProfiler;                    // uses both [gs]et_thread_profiler.
1520    friend class FlatProfilerTask;                // uses get_thread_profiler.
1521    friend class ThreadProfilerMark;              // uses get_thread_profiler.
1522    ThreadProfiler* get_thread_profiler()         { return _thread_profiler; }
1523    ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
1524      ThreadProfiler* result = _thread_profiler;
1525      _thread_profiler = tp;
1526      return result;
1527    }
1528 
1529  public:
1530   // Returns the running thread as a JavaThread
1531   static inline JavaThread* current();
1532 
1533   // Returns the active Java thread.  Do not use this if you know you are calling
1534   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1535   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1536   // operation.  You may not want that either.
1537   static JavaThread* active();
1538 
1539   inline CompilerThread* as_CompilerThread();
1540 
1541  public:
1542   virtual void run();
1543   void thread_main_inner();
1544 
1545  private:
1546   // PRIVILEGED STACK
1547   PrivilegedElement*  _privileged_stack_top;
1548   GrowableArray<oop>* _array_for_gc;
1549  public:
1550 
1551   // Returns the privileged_stack information.
1552   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1553   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1554   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1555 
1556  public:
1557   // Thread local information maintained by JVMTI.
1558   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1559   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1560   // getter is used to get this JavaThread's JvmtiThreadState if it has
1561   // one which means NULL can be returned. JvmtiThreadState::state_for()
1562   // is used to get the specified JavaThread's JvmtiThreadState if it has
1563   // one or it allocates a new JvmtiThreadState for the JavaThread and
1564   // returns it. JvmtiThreadState::state_for() will return NULL only if
1565   // the specified JavaThread is exiting.
1566   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1567   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1568   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1569   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1570 
1571   // JVMTI PopFrame support
1572   // Setting and clearing popframe_condition
1573   // All of these enumerated values are bits. popframe_pending
1574   // indicates that a PopFrame() has been requested and not yet been
1575   // completed. popframe_processing indicates that that PopFrame() is in
1576   // the process of being completed. popframe_force_deopt_reexecution_bit
1577   // indicates that special handling is required when returning to a
1578   // deoptimized caller.
1579   enum PopCondition {
1580     popframe_inactive                      = 0x00,
1581     popframe_pending_bit                   = 0x01,
1582     popframe_processing_bit                = 0x02,
1583     popframe_force_deopt_reexecution_bit   = 0x04
1584   };
1585   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1586   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1587   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1588   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1589   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1590   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1591   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1592   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1593 #ifdef CC_INTERP
1594   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1595   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1596   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1597   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1598   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1599 #endif
1600 
1601   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1602   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1603   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1604 
1605  private:
1606   // Saved incoming arguments to popped frame.
1607   // Used only when popped interpreted frame returns to deoptimized frame.
1608   void*    _popframe_preserved_args;
1609   int      _popframe_preserved_args_size;
1610 
1611  public:
1612   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1613   void* popframe_preserved_args();
1614   ByteSize popframe_preserved_args_size();
1615   WordSize popframe_preserved_args_size_in_words();
1616   void  popframe_free_preserved_args();
1617 
1618 
1619  private:
1620   JvmtiThreadState *_jvmti_thread_state;
1621   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1622 
1623   // Used by the interpreter in fullspeed mode for frame pop, method
1624   // entry, method exit and single stepping support. This field is
1625   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1626   // It can be set to zero asynchronously (i.e., without a VM operation
1627   // or a lock) so we have to be very careful.
1628   int               _interp_only_mode;
1629 
1630  public:
1631   // used by the interpreter for fullspeed debugging support (see above)
1632   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1633   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1634   int get_interp_only_mode()                { return _interp_only_mode; }
1635   void increment_interp_only_mode()         { ++_interp_only_mode; }
1636   void decrement_interp_only_mode()         { --_interp_only_mode; }
1637 
1638   // support for cached flag that indicates whether exceptions need to be posted for this thread
1639   // if this is false, we can avoid deoptimizing when events are thrown
1640   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1641  private:
1642   int    _should_post_on_exceptions_flag;
1643 
1644  public:
1645   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1646   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1647 
1648  private:
1649   ThreadStatistics *_thread_stat;
1650 
1651  public:
1652   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1653 
1654   // Return a blocker object for which this thread is blocked parking.
1655   oop current_park_blocker();
1656 
1657  private:
1658   static size_t _stack_size_at_create;
1659 
1660  public:
1661   static inline size_t stack_size_at_create(void) {
1662     return _stack_size_at_create;
1663   }
1664   static inline void set_stack_size_at_create(size_t value) {
1665     _stack_size_at_create = value;
1666   }
1667 
1668 #if INCLUDE_ALL_GCS
1669   // SATB marking queue support
1670   ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
1671   static SATBMarkQueueSet& satb_mark_queue_set() {
1672     return _satb_mark_queue_set;
1673   }
1674 
1675   // Dirty card queue support
1676   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
1677   static DirtyCardQueueSet& dirty_card_queue_set() {
1678     return _dirty_card_queue_set;
1679   }
1680 #endif // INCLUDE_ALL_GCS
1681 
1682   // This method initializes the SATB and dirty card queues before a
1683   // JavaThread is added to the Java thread list. Right now, we don't
1684   // have to do anything to the dirty card queue (it should have been
1685   // activated when the thread was created), but we have to activate
1686   // the SATB queue if the thread is created while a marking cycle is
1687   // in progress. The activation / de-activation of the SATB queues at
1688   // the beginning / end of a marking cycle is done during safepoints
1689   // so we have to make sure this method is called outside one to be
1690   // able to safely read the active field of the SATB queue set. Right
1691   // now, it is called just before the thread is added to the Java
1692   // thread list in the Threads::add() method. That method is holding
1693   // the Threads_lock which ensures we are outside a safepoint. We
1694   // cannot do the obvious and set the active field of the SATB queue
1695   // when the thread is created given that, in some cases, safepoints
1696   // might happen between the JavaThread constructor being called and the
1697   // thread being added to the Java thread list (an example of this is
1698   // when the structure for the DestroyJavaVM thread is created).
1699 #if INCLUDE_ALL_GCS
1700   void initialize_queues();
1701 #else  // INCLUDE_ALL_GCS
1702   void initialize_queues() { }
1703 #endif // INCLUDE_ALL_GCS
1704 
1705   // Machine dependent stuff
1706 #ifdef TARGET_OS_ARCH_linux_x86
1707 # include "thread_linux_x86.hpp"
1708 #endif
1709 #ifdef TARGET_OS_ARCH_linux_sparc
1710 # include "thread_linux_sparc.hpp"
1711 #endif
1712 #ifdef TARGET_OS_ARCH_linux_zero
1713 # include "thread_linux_zero.hpp"
1714 #endif
1715 #ifdef TARGET_OS_ARCH_linux_arm
1716 # include "thread_linux_arm.hpp"
1717 #endif
1718 #ifdef TARGET_OS_ARCH_linux_ppc
1719 # include "thread_linux_ppc.hpp"
1720 #endif
1721 #ifdef TARGET_OS_ARCH_linux_aarch32
1722 # include "thread_linux_aarch32.hpp"
1723 #endif
1724 #ifdef TARGET_OS_ARCH_solaris_x86
1725 # include "thread_solaris_x86.hpp"
1726 #endif
1727 #ifdef TARGET_OS_ARCH_solaris_sparc
1728 # include "thread_solaris_sparc.hpp"
1729 #endif
1730 #ifdef TARGET_OS_ARCH_windows_x86
1731 # include "thread_windows_x86.hpp"






1732 #endif
1733 #ifdef TARGET_OS_ARCH_aix_ppc
1734 # include "thread_aix_ppc.hpp"
1735 #endif
1736 #ifdef TARGET_OS_ARCH_bsd_x86
1737 # include "thread_bsd_x86.hpp"
1738 #endif
1739 #ifdef TARGET_OS_ARCH_bsd_zero
1740 # include "thread_bsd_zero.hpp"
1741 #endif
1742 
1743 
1744  public:
1745   void set_blocked_on_compilation(bool value) {
1746     _blocked_on_compilation = value;
1747   }
1748 
1749   bool blocked_on_compilation() {
1750     return _blocked_on_compilation;
1751   }
1752  protected:
1753   bool         _blocked_on_compilation;
1754 
1755 
1756   // JSR166 per-thread parker
1757 private:
1758   Parker*    _parker;
1759 public:
1760   Parker*     parker() { return _parker; }
1761 
1762   // Biased locking support
1763 private:
1764   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1765 public:
1766   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1767   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1768 
1769   // clearing/querying jni attach status
1770   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1771   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1772   inline void set_done_attaching_via_jni();
1773 private:
1774   // This field is used to determine if a thread has claimed
1775   // a par_id: it is UINT_MAX if the thread has not claimed a par_id;
1776   // otherwise its value is the par_id that has been claimed.
1777   uint _claimed_par_id;
1778 public:
1779   uint get_claimed_par_id() { return _claimed_par_id; }
1780   void set_claimed_par_id(uint id) { _claimed_par_id = id;}
1781 };
1782 
1783 // Inline implementation of JavaThread::current
1784 inline JavaThread* JavaThread::current() {
1785   Thread* thread = ThreadLocalStorage::thread();
1786   assert(thread != NULL && thread->is_Java_thread(), "just checking");
1787   return (JavaThread*)thread;
1788 }
1789 
1790 inline CompilerThread* JavaThread::as_CompilerThread() {
1791   assert(is_Compiler_thread(), "just checking");
1792   return (CompilerThread*)this;
1793 }
1794 
1795 inline bool JavaThread::stack_guard_zone_unused() {
1796   return _stack_guard_state == stack_guard_unused;
1797 }
1798 
1799 inline bool JavaThread::stack_yellow_zone_disabled() {
1800   return _stack_guard_state == stack_guard_yellow_disabled;
1801 }
1802 
1803 inline bool JavaThread::stack_yellow_zone_enabled() {
1804 #ifdef ASSERT
1805   if (os::uses_stack_guard_pages() &&
1806       !(DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
1807     assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
1808   }
1809 #endif
1810     return _stack_guard_state == stack_guard_enabled;
1811 }
1812 
1813 inline size_t JavaThread::stack_available(address cur_sp) {
1814   // This code assumes java stacks grow down
1815   address low_addr; // Limit on the address for deepest stack depth
1816   if ( _stack_guard_state == stack_guard_unused) {
1817     low_addr =  stack_base() - stack_size();
1818   } else {
1819     low_addr = stack_yellow_zone_base();
1820   }
1821   return cur_sp > low_addr ? cur_sp - low_addr : 0;
1822 }
1823 
1824 // A thread used for Compilation.
1825 class CompilerThread : public JavaThread {
1826   friend class VMStructs;
1827  private:
1828   CompilerCounters* _counters;
1829 
1830   ciEnv*            _env;
1831   CompileLog*       _log;
1832   CompileTask*      _task;
1833   CompileQueue*     _queue;
1834   BufferBlob*       _buffer_blob;
1835 
1836   nmethod*          _scanned_nmethod;  // nmethod being scanned by the sweeper
1837   AbstractCompiler* _compiler;
1838 
1839  public:
1840 
1841   static CompilerThread* current();
1842 
1843   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
1844 
1845   bool is_Compiler_thread() const                { return true; }
1846   // Hide this compiler thread from external view.
1847   bool is_hidden_from_external_view() const      { return true; }
1848 
1849   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
1850   AbstractCompiler* compiler() const             { return _compiler; }
1851 
1852   CompileQueue* queue()        const             { return _queue; }
1853   CompilerCounters* counters() const             { return _counters; }
1854 
1855   // Get/set the thread's compilation environment.
1856   ciEnv*        env()                            { return _env; }
1857   void          set_env(ciEnv* env)              { _env = env; }
1858 
1859   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
1860   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
1861 
1862   // Get/set the thread's logging information
1863   CompileLog*   log()                            { return _log; }
1864   void          init_log(CompileLog* log) {
1865     // Set once, for good.
1866     assert(_log == NULL, "set only once");
1867     _log = log;
1868   }
1869 
1870   // GC support
1871   // Apply "f->do_oop" to all root oops in "this".
1872   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
1873   void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1874 
1875 #ifndef PRODUCT
1876 private:
1877   IdealGraphPrinter *_ideal_graph_printer;
1878 public:
1879   IdealGraphPrinter *ideal_graph_printer()                       { return _ideal_graph_printer; }
1880   void set_ideal_graph_printer(IdealGraphPrinter *n)             { _ideal_graph_printer = n; }
1881 #endif
1882 
1883   // Get/set the thread's current task
1884   CompileTask*  task()                           { return _task; }
1885   void          set_task(CompileTask* task)      { _task = task; }
1886 
1887   // Track the nmethod currently being scanned by the sweeper
1888   void          set_scanned_nmethod(nmethod* nm) {
1889     assert(_scanned_nmethod == NULL || nm == NULL, "should reset to NULL before writing a new value");
1890     _scanned_nmethod = nm;
1891   }
1892 };
1893 
1894 inline CompilerThread* CompilerThread::current() {
1895   return JavaThread::current()->as_CompilerThread();
1896 }
1897 
1898 
1899 // The active thread queue. It also keeps track of the current used
1900 // thread priorities.
1901 class Threads: AllStatic {
1902   friend class VMStructs;
1903  private:
1904   static JavaThread* _thread_list;
1905   static int         _number_of_threads;
1906   static int         _number_of_non_daemon_threads;
1907   static int         _return_code;
1908 #ifdef ASSERT
1909   static bool        _vm_complete;
1910 #endif
1911 
1912  public:
1913   // Thread management
1914   // force_daemon is a concession to JNI, where we may need to add a
1915   // thread to the thread list before allocating its thread object
1916   static void add(JavaThread* p, bool force_daemon = false);
1917   static void remove(JavaThread* p);
1918   static bool includes(JavaThread* p);
1919   static JavaThread* first()                     { return _thread_list; }
1920   static void threads_do(ThreadClosure* tc);
1921 
1922   // Initializes the vm and creates the vm thread
1923   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1924   static void convert_vm_init_libraries_to_agents();
1925   static void create_vm_init_libraries();
1926   static void create_vm_init_agents();
1927   static void shutdown_vm_agents();
1928   static bool destroy_vm();
1929   // Supported VM versions via JNI
1930   // Includes JNI_VERSION_1_1
1931   static jboolean is_supported_jni_version_including_1_1(jint version);
1932   // Does not include JNI_VERSION_1_1
1933   static jboolean is_supported_jni_version(jint version);
1934 
1935   // Garbage collection
1936   static void follow_other_roots(void f(oop*));
1937 
1938   // Apply "f->do_oop" to all root oops in all threads.
1939   // This version may only be called by sequential code.
1940   static void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1941   // This version may be called by sequential or parallel code.
1942   static void possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1943   // This creates a list of GCTasks, one per thread.
1944   static void create_thread_roots_tasks(GCTaskQueue* q);
1945   // This creates a list of GCTasks, one per thread, for marking objects.
1946   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
1947 
1948   // Apply "f->do_oop" to roots in all threads that
1949   // are part of compiled frames
1950   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
1951 
1952   static void convert_hcode_pointers();
1953   static void restore_hcode_pointers();
1954 
1955   // Sweeper
1956   static void nmethods_do(CodeBlobClosure* cf);
1957 
1958   // RedefineClasses support
1959   static void metadata_do(void f(Metadata*));
1960 
1961   static void gc_epilogue();
1962   static void gc_prologue();
1963 #ifdef ASSERT
1964   static bool is_vm_complete() { return _vm_complete; }
1965 #endif
1966 
1967   // Verification
1968   static void verify();
1969   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
1970   static void print(bool print_stacks, bool internal_format) {
1971     // this function is only used by debug.cpp
1972     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
1973   }
1974   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
1975 
1976   // Get Java threads that are waiting to enter a monitor. If doLock
1977   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1978   // VM needs to be at a safepoint.
1979   static GrowableArray<JavaThread*>* get_pending_threads(int count,
1980     address monitor, bool doLock);
1981 
1982   // Get owning Java thread from the monitor's owner field. If doLock
1983   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1984   // VM needs to be at a safepoint.
1985   static JavaThread *owning_thread_from_monitor_owner(address owner,
1986     bool doLock);
1987 
1988   // Number of threads on the active threads list
1989   static int number_of_threads()                 { return _number_of_threads; }
1990   // Number of non-daemon threads on the active threads list
1991   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
1992 
1993   // Deoptimizes all frames tied to marked nmethods
1994   static void deoptimized_wrt_marked_nmethods();
1995 
1996   static JavaThread* find_java_thread_from_java_tid(jlong java_tid);
1997 
1998 };
1999 
2000 
2001 // Thread iterator
2002 class ThreadClosure: public StackObj {
2003  public:
2004   virtual void do_thread(Thread* thread) = 0;
2005 };
2006 
2007 class SignalHandlerMark: public StackObj {
2008 private:
2009   Thread* _thread;
2010 public:
2011   SignalHandlerMark(Thread* t) {
2012     _thread = t;
2013     if (_thread) _thread->enter_signal_handler();
2014   }
2015   ~SignalHandlerMark() {
2016     if (_thread) _thread->leave_signal_handler();
2017     _thread = NULL;
2018   }
2019 };
2020 
2021 
2022 #endif // SHARE_VM_RUNTIME_THREAD_HPP
--- EOF ---