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 "utilities/exceptions.hpp"
  46 #include "utilities/macros.hpp"
  47 #include "utilities/top.hpp"
  48 #if INCLUDE_ALL_GCS
  49 #include "gc_implementation/g1/dirtyCardQueue.hpp"
  50 #include "gc_implementation/g1/satbQueue.hpp"
  51 #endif // INCLUDE_ALL_GCS
  52 #ifdef TARGET_ARCH_zero
  53 # include "stack_zero.hpp"
  54 #endif
  55 #if INCLUDE_JFR
  56 #include "jfr/support/jfrThreadExtension.hpp"
  57 #endif
  58 
  59 class ThreadSafepointState;
  60 class ThreadProfiler;
  61 
  62 class JvmtiThreadState;
  63 class JvmtiGetLoadedClassesClosure;
  64 class ThreadStatistics;
  65 class ConcurrentLocksDump;
  66 class ParkEvent;
  67 class Parker;
  68 
  69 class ciEnv;
  70 class CompileThread;
  71 class CompileLog;
  72 class CompileTask;
  73 class CompileQueue;
  74 class CompilerCounters;
  75 class vframeArray;
  76 
  77 class DeoptResourceMark;
  78 class jvmtiDeferredLocalVariableSet;
  79 
  80 class GCTaskQueue;
  81 class ThreadClosure;
  82 class IdealGraphPrinter;
  83 
  84 class Metadata;
  85 template <class T, MEMFLAGS F> class ChunkedList;
  86 typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;
  87 
  88 DEBUG_ONLY(class ResourceMark;)
  89 
  90 class WorkerThread;
  91 
  92 // Class hierarchy
  93 // - Thread
  94 //   - NamedThread
  95 //     - VMThread
  96 //     - ConcurrentGCThread
  97 //     - WorkerThread
  98 //       - GangWorker
  99 //       - GCTaskThread
 100 //   - JavaThread
 101 //   - WatcherThread
 102 
 103 class Thread: public ThreadShadow {
 104   friend class VMStructs;
 105  private:
 106   // Exception handling
 107   // (Note: _pending_exception and friends are in ThreadShadow)
 108   //oop       _pending_exception;                // pending exception for current thread
 109   // const char* _exception_file;                   // file information for exception (debugging only)
 110   // int         _exception_line;                   // line information for exception (debugging only)
 111  protected:
 112   // Support for forcing alignment of thread objects for biased locking
 113   void*       _real_malloc_address;
 114  public:
 115   void* operator new(size_t size) throw() { return allocate(size, true); }
 116   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 117     return allocate(size, false); }
 118   void  operator delete(void* p);
 119 
 120  protected:
 121    static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 122  private:
 123 
 124   // ***************************************************************
 125   // Suspend and resume support
 126   // ***************************************************************
 127   //
 128   // VM suspend/resume no longer exists - it was once used for various
 129   // things including safepoints but was deprecated and finally removed
 130   // in Java 7. Because VM suspension was considered "internal" Java-level
 131   // suspension was considered "external", and this legacy naming scheme
 132   // remains.
 133   //
 134   // External suspend/resume requests come from JVM_SuspendThread,
 135   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 136   // ResumeThread. External
 137   // suspend requests cause _external_suspend to be set and external
 138   // resume requests cause _external_suspend to be cleared.
 139   // External suspend requests do not nest on top of other external
 140   // suspend requests. The higher level APIs reject suspend requests
 141   // for already suspended threads.
 142   //
 143   // The external_suspend
 144   // flag is checked by has_special_runtime_exit_condition() and java thread
 145   // will self-suspend when handle_special_runtime_exit_condition() is
 146   // called. Most uses of the _thread_blocked state in JavaThreads are
 147   // considered the same as being externally suspended; if the blocking
 148   // condition lifts, the JavaThread will self-suspend. Other places
 149   // where VM checks for external_suspend include:
 150   //   + mutex granting (do not enter monitors when thread is suspended)
 151   //   + state transitions from _thread_in_native
 152   //
 153   // In general, java_suspend() does not wait for an external suspend
 154   // request to complete. When it returns, the only guarantee is that
 155   // the _external_suspend field is true.
 156   //
 157   // wait_for_ext_suspend_completion() is used to wait for an external
 158   // suspend request to complete. External suspend requests are usually
 159   // followed by some other interface call that requires the thread to
 160   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 161   // the interface that requires quiescence, we give the JavaThread a
 162   // chance to self-suspend before we need it to be quiescent. This
 163   // improves overall suspend/query performance.
 164   //
 165   // _suspend_flags controls the behavior of java_ suspend/resume.
 166   // It must be set under the protection of SR_lock. Read from the flag is
 167   // OK without SR_lock as long as the value is only used as a hint.
 168   // (e.g., check _external_suspend first without lock and then recheck
 169   // inside SR_lock and finish the suspension)
 170   //
 171   // _suspend_flags is also overloaded for other "special conditions" so
 172   // that a single check indicates whether any special action is needed
 173   // eg. for async exceptions.
 174   // -------------------------------------------------------------------
 175   // Notes:
 176   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 177   // but we still update its value to keep other part of the system (mainly
 178   // JVMTI) happy. ThreadState is legacy code (see notes in
 179   // osThread.hpp).
 180   //
 181   // 2. It would be more natural if set_external_suspend() is private and
 182   // part of java_suspend(), but that probably would affect the suspend/query
 183   // performance. Need more investigation on this.
 184   //
 185 
 186   // suspend/resume lock: used for self-suspend
 187   Monitor* _SR_lock;
 188 
 189  protected:
 190   enum SuspendFlags {
 191     // NOTE: avoid using the sign-bit as cc generates different test code
 192     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 193 
 194     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 195     _ext_suspended          = 0x40000000U, // thread has self-suspended
 196     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 197 
 198     _has_async_exception    = 0x00000001U, // there is a pending async exception
 199     _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
 200 
 201     JFR_ONLY(_trace_flag    = 0x00000004U)  // call jfr tracing
 202   };
 203 
 204   // various suspension related flags - atomically updated
 205   // overloaded for async exception checking in check_special_condition_for_native_trans.
 206   volatile uint32_t _suspend_flags;
 207 
 208  private:
 209   int _num_nested_signal;
 210 
 211  public:
 212   void enter_signal_handler() { _num_nested_signal++; }
 213   void leave_signal_handler() { _num_nested_signal--; }
 214   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 215 
 216  private:
 217   // Debug tracing
 218   static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
 219 
 220   // Active_handles points to a block of handles
 221   JNIHandleBlock* _active_handles;
 222 
 223   // One-element thread local free list
 224   JNIHandleBlock* _free_handle_block;
 225 
 226   // Point to the last handle mark
 227   HandleMark* _last_handle_mark;
 228 
 229   // The parity of the last strong_roots iteration in which this thread was
 230   // claimed as a task.
 231   jint _oops_do_parity;
 232 
 233   public:
 234    void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 235    HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 236   private:
 237 
 238   // debug support for checking if code does allow safepoints or not
 239   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 240   // mutex, or blocking on an object synchronizer (Java locking).
 241   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 242   // If !allow_allocation(), then an assertion failure will happen during allocation
 243   // (Hence, !allow_safepoint() => !allow_allocation()).
 244   //
 245   // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
 246   //
 247   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 248   debug_only (int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 249 
 250   // Used by SkipGCALot class.
 251   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 252 
 253   friend class No_Alloc_Verifier;
 254   friend class No_Safepoint_Verifier;
 255   friend class Pause_No_Safepoint_Verifier;
 256   friend class ThreadLocalStorage;
 257   friend class GC_locker;
 258 
 259   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 260   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 261                                                 // the Java heap
 262 
 263   // Thread-local buffer used by MetadataOnStackMark.
 264   MetadataOnStackBuffer* _metadata_on_stack_buffer;
 265 
 266   JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;)      // Thread-local data for jfr
 267 
 268   ThreadExt _ext;
 269 
 270   int   _vm_operation_started_count;            // VM_Operation support
 271   int   _vm_operation_completed_count;          // VM_Operation support
 272 
 273   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
 274                                                 // is waiting to lock
 275   bool _current_pending_monitor_is_from_java;   // locking is from Java code
 276 
 277   // ObjectMonitor on which this thread called Object.wait()
 278   ObjectMonitor* _current_waiting_monitor;
 279 
 280   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
 281  public:
 282   ObjectMonitor* omFreeList;
 283   int omFreeCount;                              // length of omFreeList
 284   int omFreeProvision;                          // reload chunk size
 285   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
 286   int omInUseCount;                             // length of omInUseList
 287 
 288 #ifdef ASSERT
 289  private:
 290   bool _visited_for_critical_count;
 291 
 292  public:
 293   void set_visited_for_critical_count(bool z) { _visited_for_critical_count = z; }
 294   bool was_visited_for_critical_count() const   { return _visited_for_critical_count; }
 295 #endif
 296 
 297  public:
 298   enum {
 299     is_definitely_current_thread = true
 300   };
 301 
 302   // Constructor
 303   Thread();
 304   virtual ~Thread();
 305 
 306   // initializtion
 307   void initialize_thread_local_storage();
 308 
 309   // thread entry point
 310   virtual void run();
 311 
 312   // Testers
 313   virtual bool is_VM_thread()       const            { return false; }
 314   virtual bool is_Java_thread()     const            { return false; }
 315   virtual bool is_Compiler_thread() const            { return false; }
 316   virtual bool is_hidden_from_external_view() const  { return false; }
 317   virtual bool is_jvmti_agent_thread() const         { return false; }
 318   // True iff the thread can perform GC operations at a safepoint.
 319   // Generally will be true only of VM thread and parallel GC WorkGang
 320   // threads.
 321   virtual bool is_GC_task_thread() const             { return false; }
 322   virtual bool is_Watcher_thread() const             { return false; }
 323   virtual bool is_ConcurrentGC_thread() const        { return false; }
 324   virtual bool is_Named_thread() const               { return false; }
 325   virtual bool is_Worker_thread() const              { return false; }
 326 
 327   // Casts
 328   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
 329 
 330   virtual char* name() const { return (char*)"Unknown thread"; }
 331 
 332   // Returns the current thread
 333   static inline Thread* current();
 334 
 335   // Common thread operations
 336   static void set_priority(Thread* thread, ThreadPriority priority);
 337   static ThreadPriority get_priority(const Thread* const thread);
 338   static void start(Thread* thread);
 339   static void interrupt(Thread* thr);
 340   static bool is_interrupted(Thread* thr, bool clear_interrupted);
 341 
 342   void set_native_thread_name(const char *name) {
 343     assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
 344     os::set_native_thread_name(name);
 345   }
 346 
 347   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
 348   Monitor* SR_lock() const                       { return _SR_lock; }
 349 
 350   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
 351 
 352   void set_suspend_flag(SuspendFlags f) {
 353     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 354     uint32_t flags;
 355     do {
 356       flags = _suspend_flags;
 357     }
 358     while (Atomic::cmpxchg((jint)(flags | f),
 359                            (volatile jint*)&_suspend_flags,
 360                            (jint)flags) != (jint)flags);
 361   }
 362   void clear_suspend_flag(SuspendFlags f) {
 363     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
 364     uint32_t flags;
 365     do {
 366       flags = _suspend_flags;
 367     }
 368     while (Atomic::cmpxchg((jint)(flags & ~f),
 369                            (volatile jint*)&_suspend_flags,
 370                            (jint)flags) != (jint)flags);
 371   }
 372 
 373   void set_has_async_exception() {
 374     set_suspend_flag(_has_async_exception);
 375   }
 376   void clear_has_async_exception() {
 377     clear_suspend_flag(_has_async_exception);
 378   }
 379 
 380   bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
 381 
 382   void set_critical_native_unlock() {
 383     set_suspend_flag(_critical_native_unlock);
 384   }
 385   void clear_critical_native_unlock() {
 386     clear_suspend_flag(_critical_native_unlock);
 387   }
 388 
 389   // Support for Unhandled Oop detection
 390 #ifdef CHECK_UNHANDLED_OOPS
 391  private:
 392   UnhandledOops* _unhandled_oops;
 393  public:
 394   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
 395   // Mark oop safe for gc.  It may be stack allocated but won't move.
 396   void allow_unhandled_oop(oop *op) {
 397     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
 398   }
 399   // Clear oops at safepoint so crashes point to unhandled oop violator
 400   void clear_unhandled_oops() {
 401     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
 402   }
 403 #endif // CHECK_UNHANDLED_OOPS
 404 
 405 #ifndef PRODUCT
 406   bool skip_gcalot()           { return _skip_gcalot; }
 407   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 408 #endif
 409 
 410  public:
 411   // Installs a pending exception to be inserted later
 412   static void send_async_exception(oop thread_oop, oop java_throwable);
 413 
 414   // Resource area
 415   ResourceArea* resource_area() const            { return _resource_area; }
 416   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 417 
 418   OSThread* osthread() const                     { return _osthread;   }
 419   void set_osthread(OSThread* thread)            { _osthread = thread; }
 420 
 421   // JNI handle support
 422   JNIHandleBlock* active_handles() const         { return _active_handles; }
 423   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 424   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 425   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 426 
 427   // Internal handle support
 428   HandleArea* handle_area() const                { return _handle_area; }
 429   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 430 
 431   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 432   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 433 
 434   // Thread-Local Allocation Buffer (TLAB) support
 435   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 436   void initialize_tlab() {
 437     if (UseTLAB) {
 438       tlab().initialize();
 439     }
 440   }
 441 
 442   jlong allocated_bytes()               { return _allocated_bytes; }
 443   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 444   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 445   inline jlong cooked_allocated_bytes();
 446 
 447   JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
 448   JFR_ONLY(DEFINE_TRACE_SUSPEND_FLAG_METHODS)
 449 
 450   const ThreadExt& ext() const          { return _ext; }
 451   ThreadExt& ext()                      { return _ext; }
 452 
 453   // VM operation support
 454   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 455   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 456   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 457 
 458   // For tracking the heavyweight monitor the thread is pending on.
 459   ObjectMonitor* current_pending_monitor() {
 460     return _current_pending_monitor;
 461   }
 462   void set_current_pending_monitor(ObjectMonitor* monitor) {
 463     _current_pending_monitor = monitor;
 464   }
 465   void set_current_pending_monitor_is_from_java(bool from_java) {
 466     _current_pending_monitor_is_from_java = from_java;
 467   }
 468   bool current_pending_monitor_is_from_java() {
 469     return _current_pending_monitor_is_from_java;
 470   }
 471 
 472   // For tracking the ObjectMonitor on which this thread called Object.wait()
 473   ObjectMonitor* current_waiting_monitor() {
 474     return _current_waiting_monitor;
 475   }
 476   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 477     _current_waiting_monitor = monitor;
 478   }
 479 
 480   // GC support
 481   // Apply "f->do_oop" to all root oops in "this".
 482   // Apply "cld_f->do_cld" to CLDs that are otherwise not kept alive.
 483   //   Used by JavaThread::oops_do.
 484   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 485   virtual void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
 486 
 487   // Handles the parallel case for the method below.
 488 private:
 489   bool claim_oops_do_par_case(int collection_parity);
 490 public:
 491   // Requires that "collection_parity" is that of the current roots
 492   // iteration.  If "is_par" is false, sets the parity of "this" to
 493   // "collection_parity", and returns "true".  If "is_par" is true,
 494   // uses an atomic instruction to set the current threads parity to
 495   // "collection_parity", if it is not already.  Returns "true" iff the
 496   // calling thread does the update, this indicates that the calling thread
 497   // has claimed the thread's stack as a root groop in the current
 498   // collection.
 499   bool claim_oops_do(bool is_par, int collection_parity) {
 500     if (!is_par) {
 501       _oops_do_parity = collection_parity;
 502       return true;
 503     } else {
 504       return claim_oops_do_par_case(collection_parity);
 505     }
 506   }
 507 
 508   // Sweeper support
 509   void nmethods_do(CodeBlobClosure* cf);
 510 
 511   // jvmtiRedefineClasses support
 512   void metadata_do(void f(Metadata*));
 513 
 514   // Used by fast lock support
 515   virtual bool is_lock_owned(address adr) const;
 516 
 517   // Check if address is in the stack of the thread (not just for locks).
 518   // Warning: the method can only be used on the running thread
 519   bool is_in_stack(address adr) const;
 520   // Check if address is in the usable part of the stack (excludes protected
 521   // guard pages)
 522   bool is_in_usable_stack(address adr) const;
 523 
 524   // Sets this thread as starting thread. Returns failure if thread
 525   // creation fails due to lack of memory, too many threads etc.
 526   bool set_as_starting_thread();
 527 
 528   void set_metadata_on_stack_buffer(MetadataOnStackBuffer* buffer) { _metadata_on_stack_buffer = buffer; }
 529   MetadataOnStackBuffer* metadata_on_stack_buffer() const          { return _metadata_on_stack_buffer; }
 530 
 531 protected:
 532   // OS data associated with the thread
 533   OSThread* _osthread;  // Platform-specific thread information
 534 
 535   // Thread local resource area for temporary allocation within the VM
 536   ResourceArea* _resource_area;
 537 
 538   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 539 
 540   // Thread local handle area for allocation of handles within the VM
 541   HandleArea* _handle_area;
 542   GrowableArray<Metadata*>* _metadata_handles;
 543 
 544   // Support for stack overflow handling, get_thread, etc.
 545   address          _stack_base;
 546   size_t           _stack_size;
 547   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 548   int              _lgrp_id;
 549 
 550  public:
 551   // Stack overflow support
 552   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 553 
 554   void    set_stack_base(address base) { _stack_base = base; }
 555   size_t  stack_size() const           { return _stack_size; }
 556   void    set_stack_size(size_t size)  { _stack_size = size; }
 557   void    record_stack_base_and_size();
 558 
 559   bool    on_local_stack(address adr) const {
 560     /* QQQ this has knowledge of direction, ought to be a stack method */
 561     return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
 562   }
 563 
 564   uintptr_t self_raw_id()                    { return _self_raw_id; }
 565   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 566 
 567   int     lgrp_id() const        { return _lgrp_id; }
 568   void    set_lgrp_id(int value) { _lgrp_id = value; }
 569 
 570   // Printing
 571   void print_on(outputStream* st) const;
 572   void print() const { print_on(tty); }
 573   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 574 
 575   // Debug-only code
 576 #ifdef ASSERT
 577  private:
 578   // Deadlock detection support for Mutex locks. List of locks own by thread.
 579   Monitor* _owned_locks;
 580   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 581   // thus the friendship
 582   friend class Mutex;
 583   friend class Monitor;
 584 
 585  public:
 586   void print_owned_locks_on(outputStream* st) const;
 587   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 588   Monitor* owned_locks() const                   { return _owned_locks;          }
 589   bool owns_locks() const                        { return owned_locks() != NULL; }
 590   bool owns_locks_but_compiled_lock() const;
 591 
 592   // Deadlock detection
 593   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 594   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 595   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 596 #endif
 597 
 598   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 599 
 600  private:
 601   volatile int _jvmti_env_iteration_count;
 602 
 603  public:
 604   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 605   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 606   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 607 
 608   // Code generation
 609   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file   ); }
 610   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line   ); }
 611   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles   ); }
 612 
 613   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base ); }
 614   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size ); }
 615 
 616 #define TLAB_FIELD_OFFSET(name) \
 617   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 618 
 619   TLAB_FIELD_OFFSET(start)
 620   TLAB_FIELD_OFFSET(end)
 621   TLAB_FIELD_OFFSET(top)
 622   TLAB_FIELD_OFFSET(pf_top)
 623   TLAB_FIELD_OFFSET(size)                   // desired_size
 624   TLAB_FIELD_OFFSET(refill_waste_limit)
 625   TLAB_FIELD_OFFSET(number_of_refills)
 626   TLAB_FIELD_OFFSET(fast_refill_waste)
 627   TLAB_FIELD_OFFSET(slow_allocations)
 628 
 629 #undef TLAB_FIELD_OFFSET
 630 
 631   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes ); }
 632 
 633   JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
 634 
 635  public:
 636   volatile intptr_t _Stalled ;
 637   volatile int _TypeTag ;
 638   ParkEvent * _ParkEvent ;                     // for synchronized()
 639   ParkEvent * _SleepEvent ;                    // for Thread.sleep
 640   ParkEvent * _MutexEvent ;                    // for native internal Mutex/Monitor
 641   ParkEvent * _MuxEvent ;                      // for low-level muxAcquire-muxRelease
 642   int NativeSyncRecursion ;                    // diagnostic
 643 
 644   volatile int _OnTrap ;                       // Resume-at IP delta
 645   jint _hashStateW ;                           // Marsaglia Shift-XOR thread-local RNG
 646   jint _hashStateX ;                           // thread-specific hashCode generator state
 647   jint _hashStateY ;
 648   jint _hashStateZ ;
 649   void * _schedctl ;
 650 
 651 
 652   volatile jint rng [4] ;                      // RNG for spin loop
 653 
 654   // Low-level leaf-lock primitives used to implement synchronization
 655   // and native monitor-mutex infrastructure.
 656   // Not for general synchronization use.
 657   static void SpinAcquire (volatile int * Lock, const char * Name) ;
 658   static void SpinRelease (volatile int * Lock) ;
 659   static void muxAcquire  (volatile intptr_t * Lock, const char * Name) ;
 660   static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
 661   static void muxRelease  (volatile intptr_t * Lock) ;
 662 };
 663 
 664 // Inline implementation of Thread::current()
 665 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
 666 // startup.
 667 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
 668 // period.   This is inlined in thread_<os_family>.inline.hpp.
 669 
 670 inline Thread* Thread::current() {
 671 #ifdef ASSERT
 672 // This function is very high traffic. Define PARANOID to enable expensive
 673 // asserts.
 674 #ifdef PARANOID
 675   // Signal handler should call ThreadLocalStorage::get_thread_slow()
 676   Thread* t = ThreadLocalStorage::get_thread_slow();
 677   assert(t != NULL && !t->is_inside_signal_handler(),
 678          "Don't use Thread::current() inside signal handler");
 679 #endif
 680 #endif
 681   Thread* thread = ThreadLocalStorage::thread();
 682   assert(thread != NULL, "just checking");
 683   return thread;
 684 }
 685 
 686 // Name support for threads.  non-JavaThread subclasses with multiple
 687 // uniquely named instances should derive from this.
 688 class NamedThread: public Thread {
 689   friend class VMStructs;
 690   enum {
 691     max_name_len = 64
 692   };
 693  private:
 694   char* _name;
 695   // log JavaThread being processed by oops_do
 696   JavaThread* _processed_thread;
 697 
 698  public:
 699   NamedThread();
 700   ~NamedThread();
 701   // May only be called once per thread.
 702   void set_name(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
 703   virtual bool is_Named_thread() const { return true; }
 704   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 705   JavaThread *processed_thread() { return _processed_thread; }
 706   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 707 };
 708 
 709 // Worker threads are named and have an id of an assigned work.
 710 class WorkerThread: public NamedThread {
 711 private:
 712   uint _id;
 713 public:
 714   WorkerThread() : _id(0)               { }
 715   virtual bool is_Worker_thread() const { return true; }
 716 
 717   virtual WorkerThread* as_Worker_thread() const {
 718     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 719     return (WorkerThread*) this;
 720   }
 721 
 722   void set_id(uint work_id)             { _id = work_id; }
 723   uint id() const                       { return _id; }
 724 };
 725 
 726 // A single WatcherThread is used for simulating timer interrupts.
 727 class WatcherThread: public Thread {
 728   friend class VMStructs;
 729  public:
 730   virtual void run();
 731 
 732  private:
 733   static WatcherThread* _watcher_thread;
 734 
 735   static bool _startable;
 736   volatile static bool _should_terminate; // updated without holding lock
 737  public:
 738   enum SomeConstants {
 739     delay_interval = 10                          // interrupt delay in milliseconds
 740   };
 741 
 742   // Constructor
 743   WatcherThread();
 744 
 745   // Tester
 746   bool is_Watcher_thread() const                 { return true; }
 747 
 748   // Printing
 749   char* name() const { return (char*)"VM Periodic Task Thread"; }
 750   void print_on(outputStream* st) const;
 751   void print() const { print_on(tty); }
 752   void unpark();
 753 
 754   // Returns the single instance of WatcherThread
 755   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 756 
 757   // Create and start the single instance of WatcherThread, or stop it on shutdown
 758   static void start();
 759   static void stop();
 760   // Only allow start once the VM is sufficiently initialized
 761   // Otherwise the first task to enroll will trigger the start
 762   static void make_startable();
 763  private:
 764   int sleep() const;
 765 };
 766 
 767 
 768 class CompilerThread;
 769 
 770 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 771 
 772 class JavaThread: public Thread {
 773   friend class VMStructs;
 774  private:
 775   JavaThread*    _next;                          // The next thread in the Threads list
 776   oop            _threadObj;                     // The Java level thread object
 777 
 778 #ifdef ASSERT
 779  private:
 780   int _java_call_counter;
 781 
 782  public:
 783   int  java_call_counter()                       { return _java_call_counter; }
 784   void inc_java_call_counter()                   { _java_call_counter++; }
 785   void dec_java_call_counter() {
 786     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 787     _java_call_counter--;
 788   }
 789  private:  // restore original namespace restriction
 790 #endif  // ifdef ASSERT
 791 
 792 #ifndef PRODUCT
 793  public:
 794   enum {
 795     jump_ring_buffer_size = 16
 796   };
 797  private:  // restore original namespace restriction
 798 #endif
 799 
 800   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 801 
 802   ThreadFunction _entry_point;
 803 
 804   JNIEnv        _jni_environment;
 805 
 806   // Deopt support
 807   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 808 
 809   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 810                                                  // transition out of native
 811   nmethod*       _deopt_nmethod;                 // nmethod that is currently being deoptimized
 812   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 813   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 814   // Because deoptimization is lazy we must save jvmti requests to set locals
 815   // in compiled frames until we deoptimize and we have an interpreter frame.
 816   // This holds the pointer to array (yeah like there might be more than one) of
 817   // description of compiled vframes that have locals that need to be updated.
 818   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 819 
 820   // Handshake value for fixing 6243940. We need a place for the i2c
 821   // adapter to store the callee Method*. This value is NEVER live
 822   // across a gc point so it does NOT have to be gc'd
 823   // The handshake is open ended since we can't be certain that it will
 824   // be NULLed. This is because we rarely ever see the race and end up
 825   // in handle_wrong_method which is the backend of the handshake. See
 826   // code in i2c adapters and handle_wrong_method.
 827 
 828   Method*       _callee_target;
 829 
 830   // Used to pass back results to the interpreter or generated code running Java code.
 831   oop           _vm_result;    // oop result is GC-preserved
 832   Metadata*     _vm_result_2;  // non-oop result
 833 
 834   // See ReduceInitialCardMarks: this holds the precise space interval of
 835   // the most recent slow path allocation for which compiled code has
 836   // elided card-marks for performance along the fast-path.
 837   MemRegion     _deferred_card_mark;
 838 
 839   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 840                                                  // allocated during deoptimization
 841                                                  // and by JNI_MonitorEnter/Exit
 842 
 843   // Async. requests support
 844   enum AsyncRequests {
 845     _no_async_condition = 0,
 846     _async_exception,
 847     _async_unsafe_access_error
 848   };
 849   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 850   oop           _pending_async_exception;
 851 
 852   // Safepoint support
 853  public:                                         // Expose _thread_state for SafeFetchInt()
 854   volatile JavaThreadState _thread_state;
 855  private:
 856   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 857   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 858 
 859   // JavaThread termination support
 860   enum TerminatedTypes {
 861     _not_terminated = 0xDEAD - 2,
 862     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 863     _thread_terminated,                          // JavaThread is removed from thread list
 864     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 865                                                  // only VM_Exit can set _vm_exited
 866   };
 867 
 868   // In general a JavaThread's _terminated field transitions as follows:
 869   //
 870   //   _not_terminated => _thread_exiting => _thread_terminated
 871   //
 872   // _vm_exited is a special value to cover the case of a JavaThread
 873   // executing native code after the VM itself is terminated.
 874   volatile TerminatedTypes _terminated;
 875   // suspend/resume support
 876   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 877   jint                  _in_deopt_handler;       // count of deoptimization
 878                                                  // handlers thread is in
 879   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 880   bool                  _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
 881                                                  // never locked) when throwing an exception. Used by interpreter only.
 882 
 883   // JNI attach states:
 884   enum JNIAttachStates {
 885     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 886     _attaching_via_jni,          // thread is attaching via JNI
 887     _attached_via_jni            // thread has attached via JNI
 888   };
 889 
 890   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 891   // A native thread that is attaching via JNI starts with a value
 892   // of _attaching_via_jni and transitions to _attached_via_jni.
 893   volatile JNIAttachStates _jni_attach_state;
 894 
 895  public:
 896   // State of the stack guard pages for this thread.
 897   enum StackGuardState {
 898     stack_guard_unused,         // not needed
 899     stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
 900     stack_guard_enabled         // enabled
 901   };
 902 
 903  private:
 904 
 905   StackGuardState  _stack_guard_state;
 906 
 907   // Precompute the limit of the stack as used in stack overflow checks.
 908   // We load it from here to simplify the stack overflow check in assembly.
 909   address          _stack_overflow_limit;
 910 
 911   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 912   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 913   // code)
 914   volatile oop     _exception_oop;               // Exception thrown in compiled code
 915   volatile address _exception_pc;                // PC where exception happened
 916   volatile address _exception_handler_pc;        // PC for handler of exception
 917   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 918 
 919   // support for JNI critical regions
 920   jint    _jni_active_critical;                  // count of entries into JNI critical region
 921 
 922   // Checked JNI: function name requires exception check
 923   char* _pending_jni_exception_check_fn;
 924 
 925   // For deadlock detection.
 926   int _depth_first_number;
 927 
 928   // JVMTI PopFrame support
 929   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 930   int _popframe_condition;
 931 
 932   // If reallocation of scalar replaced objects fails, we throw OOM
 933   // and during exception propagation, pop the top
 934   // _frames_to_pop_failed_realloc frames, the ones that reference
 935   // failed reallocations.
 936   int _frames_to_pop_failed_realloc;
 937 
 938 #ifndef PRODUCT
 939   int _jmp_ring_index;
 940   struct {
 941       // We use intptr_t instead of address so debugger doesn't try and display strings
 942       intptr_t _target;
 943       intptr_t _instruction;
 944       const char*  _file;
 945       int _line;
 946   }   _jmp_ring[ jump_ring_buffer_size ];
 947 #endif /* PRODUCT */
 948 
 949 #if INCLUDE_ALL_GCS
 950   // Support for G1 barriers
 951 
 952   ObjPtrQueue _satb_mark_queue;          // Thread-local log for SATB barrier.
 953   // Set of all such queues.
 954   static SATBMarkQueueSet _satb_mark_queue_set;
 955 
 956   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.
 957   // Set of all such queues.
 958   static DirtyCardQueueSet _dirty_card_queue_set;
 959 
 960   void flush_barrier_queues();
 961 #endif // INCLUDE_ALL_GCS
 962 
 963   friend class VMThread;
 964   friend class ThreadWaitTransition;
 965   friend class VM_Exit;
 966 
 967   void initialize();                             // Initialized the instance variables
 968 
 969  public:
 970   // Constructor
 971   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
 972   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
 973   ~JavaThread();
 974 
 975 #ifdef ASSERT
 976   // verify this JavaThread hasn't be published in the Threads::list yet
 977   void verify_not_published();
 978 #endif
 979 
 980   //JNI functiontable getter/setter for JVMTI jni function table interception API.
 981   void set_jni_functions(struct JNINativeInterface_* functionTable) {
 982     _jni_environment.functions = functionTable;
 983   }
 984   struct JNINativeInterface_* get_jni_functions() {
 985     return (struct JNINativeInterface_ *)_jni_environment.functions;
 986   }
 987 
 988   // This function is called at thread creation to allow
 989   // platform specific thread variables to be initialized.
 990   void cache_global_variables();
 991 
 992   // Executes Shutdown.shutdown()
 993   void invoke_shutdown_hooks();
 994 
 995   // Cleanup on thread exit
 996   enum ExitType {
 997     normal_exit,
 998     jni_detach
 999   };
1000   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1001 
1002   void cleanup_failed_attach_current_thread();
1003 
1004   // Testers
1005   virtual bool is_Java_thread() const            { return true;  }
1006 
1007   // Thread chain operations
1008   JavaThread* next() const                       { return _next; }
1009   void set_next(JavaThread* p)                   { _next = p; }
1010 
1011   // Thread oop. threadObj() can be NULL for initial JavaThread
1012   // (or for threads attached via JNI)
1013   oop threadObj() const                          { return _threadObj; }
1014   void set_threadObj(oop p)                      { _threadObj = p; }
1015 
1016   ThreadPriority java_priority() const;          // Read from threadObj()
1017 
1018   // Prepare thread and add to priority queue.  If a priority is
1019   // not specified, use the priority of the thread object. Threads_lock
1020   // must be held while this function is called.
1021   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1022   void prepare_ext();
1023 
1024   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1025   address saved_exception_pc()                   { return _saved_exception_pc; }
1026 
1027 
1028   ThreadFunction entry_point() const             { return _entry_point; }
1029 
1030   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1031   void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
1032 
1033   // Last frame anchor routines
1034 
1035   JavaFrameAnchor* frame_anchor(void)            { return &_anchor; }
1036 
1037   // last_Java_sp
1038   bool has_last_Java_frame() const               { return _anchor.has_last_Java_frame(); }
1039   intptr_t* last_Java_sp() const                 { return _anchor.last_Java_sp(); }
1040 
1041   // last_Java_pc
1042 
1043   address last_Java_pc(void)                     { return _anchor.last_Java_pc(); }
1044 
1045   // Safepoint support
1046 #ifndef PPC64
1047   JavaThreadState thread_state() const           { return _thread_state; }
1048   void set_thread_state(JavaThreadState s)       { _thread_state = s;    }
1049 #else
1050   // Use membars when accessing volatile _thread_state. See
1051   // Threads::create_vm() for size checks.
1052   inline JavaThreadState thread_state() const;
1053   inline void set_thread_state(JavaThreadState s);
1054 #endif
1055   ThreadSafepointState *safepoint_state() const  { return _safepoint_state; }
1056   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1057   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1058 
1059   // thread has called JavaThread::exit() or is terminated
1060   bool is_exiting()                              { return _terminated == _thread_exiting || is_terminated(); }
1061   // thread is terminated (no longer on the threads list); we compare
1062   // against the two non-terminated values so that a freed JavaThread
1063   // will also be considered terminated.
1064   bool is_terminated()                           { return _terminated != _not_terminated && _terminated != _thread_exiting; }
1065   void set_terminated(TerminatedTypes t)         { _terminated = t; }
1066   // special for Threads::remove() which is static:
1067   void set_terminated_value()                    { _terminated = _thread_terminated; }
1068   void block_if_vm_exited();
1069 
1070   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1071   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1072 
1073   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1074   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1075 
1076   // Suspend/resume support for JavaThread
1077  private:
1078   void set_ext_suspended()       { set_suspend_flag (_ext_suspended);  }
1079   void clear_ext_suspended()     { clear_suspend_flag(_ext_suspended); }
1080 
1081  public:
1082   void java_suspend();
1083   void java_resume();
1084   int  java_suspend_self();
1085 
1086   void check_and_wait_while_suspended() {
1087     assert(JavaThread::current() == this, "sanity check");
1088 
1089     bool do_self_suspend;
1090     do {
1091       // were we externally suspended while we were waiting?
1092       do_self_suspend = handle_special_suspend_equivalent_condition();
1093       if (do_self_suspend) {
1094         // don't surprise the thread that suspended us by returning
1095         java_suspend_self();
1096         set_suspend_equivalent();
1097       }
1098     } while (do_self_suspend);
1099   }
1100   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1101   // Check for async exception in addition to safepoint and suspend request.
1102   static void check_special_condition_for_native_trans(JavaThread *thread);
1103 
1104   // Same as check_special_condition_for_native_trans but finishes the
1105   // transition into thread_in_Java mode so that it can potentially
1106   // block.
1107   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1108 
1109   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1110   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1111     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1112     // Warning: is_ext_suspend_completed() may temporarily drop the
1113     // SR_lock to allow the thread to reach a stable thread state if
1114     // it is currently in a transient thread state.
1115     return is_ext_suspend_completed(false /*!called_by_wait */,
1116                                     SuspendRetryDelay, bits);
1117   }
1118 
1119   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1120   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1121   // passed as the count and delay parameters. Experiments with specific
1122   // calls to wait_for_ext_suspend_completion() can be done by passing
1123   // other values in the code. Experiments with all calls can be done
1124   // via the appropriate -XX options.
1125   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1126 
1127   void set_external_suspend()     { set_suspend_flag  (_external_suspend); }
1128   void clear_external_suspend()   { clear_suspend_flag(_external_suspend); }
1129 
1130   void set_deopt_suspend()        { set_suspend_flag  (_deopt_suspend); }
1131   void clear_deopt_suspend()      { clear_suspend_flag(_deopt_suspend); }
1132   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1133 
1134   bool is_external_suspend() const {
1135     return (_suspend_flags & _external_suspend) != 0;
1136   }
1137   // Whenever a thread transitions from native to vm/java it must suspend
1138   // if external|deopt suspend is present.
1139   bool is_suspend_after_native() const {
1140     return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
1141   }
1142 
1143   // external suspend request is completed
1144   bool is_ext_suspended() const {
1145     return (_suspend_flags & _ext_suspended) != 0;
1146   }
1147 
1148   bool is_external_suspend_with_lock() const {
1149     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1150     return is_external_suspend();
1151   }
1152 
1153   // Special method to handle a pending external suspend request
1154   // when a suspend equivalent condition lifts.
1155   bool handle_special_suspend_equivalent_condition() {
1156     assert(is_suspend_equivalent(),
1157       "should only be called in a suspend equivalence condition");
1158     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1159     bool ret = is_external_suspend();
1160     if (!ret) {
1161       // not about to self-suspend so clear suspend equivalence
1162       clear_suspend_equivalent();
1163     }
1164     // implied else:
1165     // We have a pending external suspend request so we leave the
1166     // suspend_equivalent flag set until java_suspend_self() sets
1167     // the ext_suspended flag and clears the suspend_equivalent
1168     // flag. This insures that wait_for_ext_suspend_completion()
1169     // will return consistent values.
1170     return ret;
1171   }
1172 
1173   // utility methods to see if we are doing some kind of suspension
1174   bool is_being_ext_suspended() const            {
1175     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1176     return is_ext_suspended() || is_external_suspend();
1177   }
1178 
1179   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1180 
1181   void set_suspend_equivalent()                  { _suspend_equivalent = true; };
1182   void clear_suspend_equivalent()                { _suspend_equivalent = false; };
1183 
1184   // Thread.stop support
1185   void send_thread_stop(oop throwable);
1186   AsyncRequests clear_special_runtime_exit_condition() {
1187     AsyncRequests x = _special_runtime_exit_condition;
1188     _special_runtime_exit_condition = _no_async_condition;
1189     return x;
1190   }
1191 
1192   // Are any async conditions present?
1193   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1194 
1195   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1196 
1197   // these next two are also used for self-suspension and async exception support
1198   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1199 
1200   // Return true if JavaThread has an asynchronous condition or
1201   // if external suspension is requested.
1202   bool has_special_runtime_exit_condition() {
1203     // We call is_external_suspend() last since external suspend should
1204     // be less common. Because we don't use is_external_suspend_with_lock
1205     // it is possible that we won't see an asynchronous external suspend
1206     // request that has just gotten started, i.e., SR_lock grabbed but
1207     // _external_suspend field change either not made yet or not visible
1208     // yet. However, this is okay because the request is asynchronous and
1209     // we will see the new flag value the next time through. It's also
1210     // possible that the external suspend request is dropped after
1211     // we have checked is_external_suspend(), we will recheck its value
1212     // under SR_lock in java_suspend_self().
1213     return (_special_runtime_exit_condition != _no_async_condition) ||
1214             is_external_suspend() || is_deopt_suspend();
1215   }
1216 
1217   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1218 
1219   void set_pending_async_exception(oop e) {
1220     _pending_async_exception = e;
1221     _special_runtime_exit_condition = _async_exception;
1222     set_has_async_exception();
1223   }
1224 
1225   // Fast-locking support
1226   bool is_lock_owned(address adr) const;
1227 
1228   // Accessors for vframe array top
1229   // The linked list of vframe arrays are sorted on sp. This means when we
1230   // unpack the head must contain the vframe array to unpack.
1231   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1232   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1233 
1234   // Side structure for defering update of java frame locals until deopt occurs
1235   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1236   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1237 
1238   // These only really exist to make debugging deopt problems simpler
1239 
1240   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1241   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1242 
1243   // The special resourceMark used during deoptimization
1244 
1245   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1246   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1247 
1248   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1249   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1250   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1251 
1252   void set_deopt_nmethod(nmethod* nm)            { _deopt_nmethod = nm;   }
1253   nmethod* deopt_nmethod()                       { return _deopt_nmethod; }
1254 
1255   Method*    callee_target() const               { return _callee_target; }
1256   void set_callee_target  (Method* x)          { _callee_target   = x; }
1257 
1258   // Oop results of vm runtime calls
1259   oop  vm_result() const                         { return _vm_result; }
1260   void set_vm_result  (oop x)                    { _vm_result   = x; }
1261 
1262   Metadata*    vm_result_2() const               { return _vm_result_2; }
1263   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1264 
1265   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1266   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1267 
1268   // Exception handling for compiled methods
1269   oop      exception_oop() const                 { return _exception_oop; }
1270   address  exception_pc() const                  { return _exception_pc; }
1271   address  exception_handler_pc() const          { return _exception_handler_pc; }
1272   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1273 
1274   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1275   void set_exception_pc(address a)               { _exception_pc = a; }
1276   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1277   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1278 
1279   void clear_exception_oop_and_pc() {
1280     set_exception_oop(NULL);
1281     set_exception_pc(NULL);
1282   }
1283 
1284   // Stack overflow support
1285   inline size_t stack_available(address cur_sp);
1286   address stack_yellow_zone_base()
1287     { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
1288   size_t  stack_yellow_zone_size()
1289     { return StackYellowPages * os::vm_page_size(); }
1290   address stack_red_zone_base()
1291     { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
1292   size_t stack_red_zone_size()
1293     { return StackRedPages * os::vm_page_size(); }
1294   bool in_stack_yellow_zone(address a)
1295     { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
1296   bool in_stack_red_zone(address a)
1297     { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
1298 
1299   void create_stack_guard_pages();
1300   void remove_stack_guard_pages();
1301 
1302   void enable_stack_yellow_zone();
1303   void disable_stack_yellow_zone();
1304   void enable_stack_red_zone();
1305   void disable_stack_red_zone();
1306 
1307   inline bool stack_guard_zone_unused();
1308   inline bool stack_yellow_zone_disabled();
1309   inline bool stack_yellow_zone_enabled();
1310 
1311   // Attempt to reguard the stack after a stack overflow may have occurred.
1312   // Returns true if (a) guard pages are not needed on this thread, (b) the
1313   // pages are already guarded, or (c) the pages were successfully reguarded.
1314   // Returns false if there is not enough stack space to reguard the pages, in
1315   // which case the caller should unwind a frame and try again.  The argument
1316   // should be the caller's (approximate) sp.
1317   bool reguard_stack(address cur_sp);
1318   // Similar to above but see if current stackpoint is out of the guard area
1319   // and reguard if possible.
1320   bool reguard_stack(void);
1321 
1322   address stack_overflow_limit() { return _stack_overflow_limit; }
1323   void set_stack_overflow_limit() {
1324     _stack_overflow_limit = _stack_base - _stack_size +
1325                             ((StackShadowPages +
1326                               StackYellowPages +
1327                               StackRedPages) * os::vm_page_size());
1328   }
1329 
1330   // Misc. accessors/mutators
1331   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1332   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1333   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1334 
1335 #ifndef PRODUCT
1336   void record_jump(address target, address instr, const char* file, int line);
1337 #endif /* PRODUCT */
1338 
1339   // For assembly stub generation
1340   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj           ); }
1341 #ifndef PRODUCT
1342   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index      ); }
1343   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring            ); }
1344 #endif /* PRODUCT */
1345   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment     ); }
1346   static ByteSize last_Java_sp_offset()          {
1347     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1348   }
1349   static ByteSize last_Java_pc_offset()          {
1350     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1351   }
1352   static ByteSize frame_anchor_offset()          {
1353     return byte_offset_of(JavaThread, _anchor);
1354   }
1355   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target       ); }
1356   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result           ); }
1357   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2         ); }
1358   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state        ); }
1359   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
1360   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
1361   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
1362   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
1363   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1364   static ByteSize stack_overflow_limit_offset()  { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1365   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1366   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
1367   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
1368 
1369   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1370   static ByteSize should_post_on_exceptions_flag_offset() {
1371     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1372   }
1373 
1374 #if INCLUDE_ALL_GCS
1375   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
1376   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
1377 #endif // INCLUDE_ALL_GCS
1378 
1379   // Returns the jni environment for this thread
1380   JNIEnv* jni_environment()                      { return &_jni_environment; }
1381 
1382   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1383     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1384     // Only return NULL if thread is off the thread list; starting to
1385     // exit should not return NULL.
1386     if (thread_from_jni_env->is_terminated()) {
1387        thread_from_jni_env->block_if_vm_exited();
1388        return NULL;
1389     } else {
1390        return thread_from_jni_env;
1391     }
1392   }
1393 
1394   // JNI critical regions. These can nest.
1395   bool in_critical()    { return _jni_active_critical > 0; }
1396   bool in_last_critical()  { return _jni_active_critical == 1; }
1397   void enter_critical() { assert(Thread::current() == this ||
1398                                  Thread::current()->is_VM_thread() && SafepointSynchronize::is_synchronizing(),
1399                                  "this must be current thread or synchronizing");
1400                           _jni_active_critical++; }
1401   void exit_critical()  { assert(Thread::current() == this,
1402                                  "this must be current thread");
1403                           _jni_active_critical--;
1404                           assert(_jni_active_critical >= 0,
1405                                  "JNI critical nesting problem?"); }
1406 
1407   // Checked JNI, is the programmer required to check for exceptions, specify which function name
1408   bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1409   void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1410   const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1411   void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1412 
1413   // For deadlock detection
1414   int depth_first_number() { return _depth_first_number; }
1415   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1416 
1417  private:
1418   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1419 
1420  public:
1421   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1422   void add_monitor_chunk(MonitorChunk* chunk);
1423   void remove_monitor_chunk(MonitorChunk* chunk);
1424   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1425   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1426   void dec_in_deopt_handler()                    {
1427     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1428     if (_in_deopt_handler > 0) { // robustness
1429       _in_deopt_handler--;
1430     }
1431   }
1432 
1433  private:
1434   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1435 
1436  public:
1437 
1438   // Frame iteration; calls the function f for all frames on the stack
1439   void frames_do(void f(frame*, const RegisterMap*));
1440 
1441   // Memory operations
1442   void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1443 
1444   // Sweeper operations
1445   void nmethods_do(CodeBlobClosure* cf);
1446 
1447   // RedefineClasses Support
1448   void metadata_do(void f(Metadata*));
1449 
1450   // Memory management operations
1451   void gc_epilogue();
1452   void gc_prologue();
1453 
1454   // Misc. operations
1455   char* name() const { return (char*)get_thread_name(); }
1456   void print_on(outputStream* st) const;
1457   void print() const { print_on(tty); }
1458   void print_value();
1459   void print_thread_state_on(outputStream* ) const      PRODUCT_RETURN;
1460   void print_thread_state() const                       PRODUCT_RETURN;
1461   void print_on_error(outputStream* st, char* buf, int buflen) const;
1462   void verify();
1463   const char* get_thread_name() const;
1464 private:
1465   // factor out low-level mechanics for use in both normal and error cases
1466   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1467 public:
1468   const char* get_threadgroup_name() const;
1469   const char* get_parent_name() const;
1470 
1471   // Accessing frames
1472   frame last_frame() {
1473     _anchor.make_walkable(this);
1474     return pd_last_frame();
1475   }
1476   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1477 
1478   // Returns method at 'depth' java or native frames down the stack
1479   // Used for security checks
1480   Klass* security_get_caller_class(int depth);
1481 
1482   // Print stack trace in external format
1483   void print_stack_on(outputStream* st);
1484   void print_stack() { print_stack_on(tty); }
1485 
1486   // Print stack traces in various internal formats
1487   void trace_stack()                             PRODUCT_RETURN;
1488   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1489   void trace_frames()                            PRODUCT_RETURN;
1490   void trace_oops()                              PRODUCT_RETURN;
1491 
1492   // Print an annotated view of the stack frames
1493   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1494   void validate_frame_layout() {
1495     print_frame_layout(0, true);
1496   }
1497 
1498   // Returns the number of stack frames on the stack
1499   int depth() const;
1500 
1501   // Function for testing deoptimization
1502   void deoptimize();
1503   void make_zombies();
1504 
1505   void deoptimized_wrt_marked_nmethods();
1506 
1507   // Profiling operation (see fprofile.cpp)
1508  public:
1509    bool profile_last_Java_frame(frame* fr);
1510 
1511  private:
1512    ThreadProfiler* _thread_profiler;
1513  private:
1514    friend class FlatProfiler;                    // uses both [gs]et_thread_profiler.
1515    friend class FlatProfilerTask;                // uses get_thread_profiler.
1516    friend class ThreadProfilerMark;              // uses get_thread_profiler.
1517    ThreadProfiler* get_thread_profiler()         { return _thread_profiler; }
1518    ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
1519      ThreadProfiler* result = _thread_profiler;
1520      _thread_profiler = tp;
1521      return result;
1522    }
1523 
1524  public:
1525   // Returns the running thread as a JavaThread
1526   static inline JavaThread* current();
1527 
1528   // Returns the active Java thread.  Do not use this if you know you are calling
1529   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1530   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1531   // operation.  You may not want that either.
1532   static JavaThread* active();
1533 
1534   inline CompilerThread* as_CompilerThread();
1535 
1536  public:
1537   virtual void run();
1538   void thread_main_inner();
1539 
1540  private:
1541   // PRIVILEGED STACK
1542   PrivilegedElement*  _privileged_stack_top;
1543   GrowableArray<oop>* _array_for_gc;
1544  public:
1545 
1546   // Returns the privileged_stack information.
1547   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1548   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1549   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1550 
1551  public:
1552   // Thread local information maintained by JVMTI.
1553   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1554   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1555   // getter is used to get this JavaThread's JvmtiThreadState if it has
1556   // one which means NULL can be returned. JvmtiThreadState::state_for()
1557   // is used to get the specified JavaThread's JvmtiThreadState if it has
1558   // one or it allocates a new JvmtiThreadState for the JavaThread and
1559   // returns it. JvmtiThreadState::state_for() will return NULL only if
1560   // the specified JavaThread is exiting.
1561   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1562   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1563   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1564   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1565 
1566   // JVMTI PopFrame support
1567   // Setting and clearing popframe_condition
1568   // All of these enumerated values are bits. popframe_pending
1569   // indicates that a PopFrame() has been requested and not yet been
1570   // completed. popframe_processing indicates that that PopFrame() is in
1571   // the process of being completed. popframe_force_deopt_reexecution_bit
1572   // indicates that special handling is required when returning to a
1573   // deoptimized caller.
1574   enum PopCondition {
1575     popframe_inactive                      = 0x00,
1576     popframe_pending_bit                   = 0x01,
1577     popframe_processing_bit                = 0x02,
1578     popframe_force_deopt_reexecution_bit   = 0x04
1579   };
1580   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1581   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1582   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1583   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1584   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1585   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1586   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1587   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1588 #ifdef CC_INTERP
1589   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1590   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1591   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1592   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1593   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1594 #endif
1595 
1596   int frames_to_pop_failed_realloc() const            { return _frames_to_pop_failed_realloc; }
1597   void set_frames_to_pop_failed_realloc(int nb)       { _frames_to_pop_failed_realloc = nb; }
1598   void dec_frames_to_pop_failed_realloc()             { _frames_to_pop_failed_realloc--; }
1599 
1600  private:
1601   // Saved incoming arguments to popped frame.
1602   // Used only when popped interpreted frame returns to deoptimized frame.
1603   void*    _popframe_preserved_args;
1604   int      _popframe_preserved_args_size;
1605 
1606  public:
1607   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1608   void* popframe_preserved_args();
1609   ByteSize popframe_preserved_args_size();
1610   WordSize popframe_preserved_args_size_in_words();
1611   void  popframe_free_preserved_args();
1612 
1613 
1614  private:
1615   JvmtiThreadState *_jvmti_thread_state;
1616   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1617 
1618   // Used by the interpreter in fullspeed mode for frame pop, method
1619   // entry, method exit and single stepping support. This field is
1620   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1621   // It can be set to zero asynchronously (i.e., without a VM operation
1622   // or a lock) so we have to be very careful.
1623   int               _interp_only_mode;
1624 
1625  public:
1626   // used by the interpreter for fullspeed debugging support (see above)
1627   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1628   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1629   int get_interp_only_mode()                { return _interp_only_mode; }
1630   void increment_interp_only_mode()         { ++_interp_only_mode; }
1631   void decrement_interp_only_mode()         { --_interp_only_mode; }
1632 
1633   // support for cached flag that indicates whether exceptions need to be posted for this thread
1634   // if this is false, we can avoid deoptimizing when events are thrown
1635   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1636  private:
1637   int    _should_post_on_exceptions_flag;
1638 
1639  public:
1640   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1641   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1642 
1643  private:
1644   ThreadStatistics *_thread_stat;
1645 
1646  public:
1647   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1648 
1649   // Return a blocker object for which this thread is blocked parking.
1650   oop current_park_blocker();
1651 
1652  private:
1653   static size_t _stack_size_at_create;
1654 
1655  public:
1656   static inline size_t stack_size_at_create(void) {
1657     return _stack_size_at_create;
1658   }
1659   static inline void set_stack_size_at_create(size_t value) {
1660     _stack_size_at_create = value;
1661   }
1662 
1663 #if INCLUDE_ALL_GCS
1664   // SATB marking queue support
1665   ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
1666   static SATBMarkQueueSet& satb_mark_queue_set() {
1667     return _satb_mark_queue_set;
1668   }
1669 
1670   // Dirty card queue support
1671   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
1672   static DirtyCardQueueSet& dirty_card_queue_set() {
1673     return _dirty_card_queue_set;
1674   }
1675 #endif // INCLUDE_ALL_GCS
1676 
1677   // This method initializes the SATB and dirty card queues before a
1678   // JavaThread is added to the Java thread list. Right now, we don't
1679   // have to do anything to the dirty card queue (it should have been
1680   // activated when the thread was created), but we have to activate
1681   // the SATB queue if the thread is created while a marking cycle is
1682   // in progress. The activation / de-activation of the SATB queues at
1683   // the beginning / end of a marking cycle is done during safepoints
1684   // so we have to make sure this method is called outside one to be
1685   // able to safely read the active field of the SATB queue set. Right
1686   // now, it is called just before the thread is added to the Java
1687   // thread list in the Threads::add() method. That method is holding
1688   // the Threads_lock which ensures we are outside a safepoint. We
1689   // cannot do the obvious and set the active field of the SATB queue
1690   // when the thread is created given that, in some cases, safepoints
1691   // might happen between the JavaThread constructor being called and the
1692   // thread being added to the Java thread list (an example of this is
1693   // when the structure for the DestroyJavaVM thread is created).
1694 #if INCLUDE_ALL_GCS
1695   void initialize_queues();
1696 #else  // INCLUDE_ALL_GCS
1697   void initialize_queues() { }
1698 #endif // INCLUDE_ALL_GCS
1699 
1700   // Machine dependent stuff
1701 #ifdef TARGET_OS_ARCH_linux_x86
1702 # include "thread_linux_x86.hpp"
1703 #endif
1704 #ifdef TARGET_OS_ARCH_linux_sparc
1705 # include "thread_linux_sparc.hpp"
1706 #endif
1707 #ifdef TARGET_OS_ARCH_linux_zero
1708 # include "thread_linux_zero.hpp"
1709 #endif
1710 #ifdef TARGET_OS_ARCH_solaris_x86
1711 # include "thread_solaris_x86.hpp"
1712 #endif
1713 #ifdef TARGET_OS_ARCH_solaris_sparc
1714 # include "thread_solaris_sparc.hpp"
1715 #endif
1716 #ifdef TARGET_OS_ARCH_windows_x86
1717 # include "thread_windows_x86.hpp"
1718 #endif
1719 #ifdef TARGET_OS_ARCH_linux_arm
1720 # include "thread_linux_arm.hpp"
1721 #endif
1722 #ifdef TARGET_OS_ARCH_linux_ppc
1723 # include "thread_linux_ppc.hpp"
1724 #endif
1725 #ifdef TARGET_OS_ARCH_aix_ppc
1726 # include "thread_aix_ppc.hpp"
1727 #endif
1728 #ifdef TARGET_OS_ARCH_bsd_x86
1729 # include "thread_bsd_x86.hpp"
1730 #endif
1731 #ifdef TARGET_OS_ARCH_bsd_zero
1732 # include "thread_bsd_zero.hpp"
1733 #endif
1734 
1735 
1736  public:
1737   void set_blocked_on_compilation(bool value) {
1738     _blocked_on_compilation = value;
1739   }
1740 
1741   bool blocked_on_compilation() {
1742     return _blocked_on_compilation;
1743   }
1744  protected:
1745   bool         _blocked_on_compilation;
1746 
1747 
1748   // JSR166 per-thread parker
1749 private:
1750   Parker*    _parker;
1751 public:
1752   Parker*     parker() { return _parker; }
1753 
1754   // Biased locking support
1755 private:
1756   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1757 public:
1758   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1759   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1760 
1761   // clearing/querying jni attach status
1762   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1763   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1764   inline void set_done_attaching_via_jni();
1765 private:
1766   // This field is used to determine if a thread has claimed
1767   // a par_id: it is UINT_MAX if the thread has not claimed a par_id;
1768   // otherwise its value is the par_id that has been claimed.
1769   uint _claimed_par_id;
1770 public:
1771   uint get_claimed_par_id() { return _claimed_par_id; }
1772   void set_claimed_par_id(uint id) { _claimed_par_id = id;}
1773 };
1774 
1775 // Inline implementation of JavaThread::current
1776 inline JavaThread* JavaThread::current() {
1777   Thread* thread = ThreadLocalStorage::thread();
1778   assert(thread != NULL && thread->is_Java_thread(), "just checking");
1779   return (JavaThread*)thread;
1780 }
1781 
1782 inline CompilerThread* JavaThread::as_CompilerThread() {
1783   assert(is_Compiler_thread(), "just checking");
1784   return (CompilerThread*)this;
1785 }
1786 
1787 inline bool JavaThread::stack_guard_zone_unused() {
1788   return _stack_guard_state == stack_guard_unused;
1789 }
1790 
1791 inline bool JavaThread::stack_yellow_zone_disabled() {
1792   return _stack_guard_state == stack_guard_yellow_disabled;
1793 }
1794 
1795 inline bool JavaThread::stack_yellow_zone_enabled() {
1796 #ifdef ASSERT
1797   if (os::uses_stack_guard_pages() &&
1798       !(DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
1799     assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
1800   }
1801 #endif
1802     return _stack_guard_state == stack_guard_enabled;
1803 }
1804 
1805 inline size_t JavaThread::stack_available(address cur_sp) {
1806   // This code assumes java stacks grow down
1807   address low_addr; // Limit on the address for deepest stack depth
1808   if ( _stack_guard_state == stack_guard_unused) {
1809     low_addr =  stack_base() - stack_size();
1810   } else {
1811     low_addr = stack_yellow_zone_base();
1812   }
1813   return cur_sp > low_addr ? cur_sp - low_addr : 0;
1814 }
1815 
1816 // A thread used for Compilation.
1817 class CompilerThread : public JavaThread {
1818   friend class VMStructs;
1819  private:
1820   CompilerCounters* _counters;
1821 
1822   ciEnv*            _env;
1823   CompileLog*       _log;
1824   CompileTask*      _task;
1825   CompileQueue*     _queue;
1826   BufferBlob*       _buffer_blob;
1827 
1828   nmethod*          _scanned_nmethod;  // nmethod being scanned by the sweeper
1829   AbstractCompiler* _compiler;
1830 
1831  public:
1832 
1833   static CompilerThread* current();
1834 
1835   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
1836 
1837   bool is_Compiler_thread() const                { return true; }
1838   // Hide this compiler thread from external view.
1839   bool is_hidden_from_external_view() const      { return true; }
1840 
1841   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
1842   AbstractCompiler* compiler() const             { return _compiler; }
1843 
1844   CompileQueue* queue()        const             { return _queue; }
1845   CompilerCounters* counters() const             { return _counters; }
1846 
1847   // Get/set the thread's compilation environment.
1848   ciEnv*        env()                            { return _env; }
1849   void          set_env(ciEnv* env)              { _env = env; }
1850 
1851   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
1852   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
1853 
1854   // Get/set the thread's logging information
1855   CompileLog*   log()                            { return _log; }
1856   void          init_log(CompileLog* log) {
1857     // Set once, for good.
1858     assert(_log == NULL, "set only once");
1859     _log = log;
1860   }
1861 
1862   // GC support
1863   // Apply "f->do_oop" to all root oops in "this".
1864   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
1865   void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1866 
1867 #ifndef PRODUCT
1868 private:
1869   IdealGraphPrinter *_ideal_graph_printer;
1870 public:
1871   IdealGraphPrinter *ideal_graph_printer()                       { return _ideal_graph_printer; }
1872   void set_ideal_graph_printer(IdealGraphPrinter *n)             { _ideal_graph_printer = n; }
1873 #endif
1874 
1875   // Get/set the thread's current task
1876   CompileTask*  task()                           { return _task; }
1877   void          set_task(CompileTask* task)      { _task = task; }
1878 
1879   // Track the nmethod currently being scanned by the sweeper
1880   void          set_scanned_nmethod(nmethod* nm) {
1881     assert(_scanned_nmethod == NULL || nm == NULL, "should reset to NULL before writing a new value");
1882     _scanned_nmethod = nm;
1883   }
1884 };
1885 
1886 inline CompilerThread* CompilerThread::current() {
1887   return JavaThread::current()->as_CompilerThread();
1888 }
1889 
1890 
1891 // The active thread queue. It also keeps track of the current used
1892 // thread priorities.
1893 class Threads: AllStatic {
1894   friend class VMStructs;
1895  private:
1896   static JavaThread* _thread_list;
1897   static int         _number_of_threads;
1898   static int         _number_of_non_daemon_threads;
1899   static int         _return_code;
1900 #ifdef ASSERT
1901   static bool        _vm_complete;
1902 #endif
1903 
1904  public:
1905   // Thread management
1906   // force_daemon is a concession to JNI, where we may need to add a
1907   // thread to the thread list before allocating its thread object
1908   static void add(JavaThread* p, bool force_daemon = false);
1909   static void remove(JavaThread* p);
1910   static bool includes(JavaThread* p);
1911   static JavaThread* first()                     { return _thread_list; }
1912   static void threads_do(ThreadClosure* tc);
1913 
1914   // Initializes the vm and creates the vm thread
1915   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1916   static void convert_vm_init_libraries_to_agents();
1917   static void create_vm_init_libraries();
1918   static void create_vm_init_agents();
1919   static void shutdown_vm_agents();
1920   static bool destroy_vm();
1921   // Supported VM versions via JNI
1922   // Includes JNI_VERSION_1_1
1923   static jboolean is_supported_jni_version_including_1_1(jint version);
1924   // Does not include JNI_VERSION_1_1
1925   static jboolean is_supported_jni_version(jint version);
1926 
1927   // Garbage collection
1928   static void follow_other_roots(void f(oop*));
1929 
1930   // Apply "f->do_oop" to all root oops in all threads.
1931   // This version may only be called by sequential code.
1932   static void oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1933   // This version may be called by sequential or parallel code.
1934   static void possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf);
1935   // This creates a list of GCTasks, one per thread.
1936   static void create_thread_roots_tasks(GCTaskQueue* q);
1937   // This creates a list of GCTasks, one per thread, for marking objects.
1938   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
1939 
1940   // Apply "f->do_oop" to roots in all threads that
1941   // are part of compiled frames
1942   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
1943 
1944   static void convert_hcode_pointers();
1945   static void restore_hcode_pointers();
1946 
1947   // Sweeper
1948   static void nmethods_do(CodeBlobClosure* cf);
1949 
1950   // RedefineClasses support
1951   static void metadata_do(void f(Metadata*));
1952 
1953   static void gc_epilogue();
1954   static void gc_prologue();
1955 #ifdef ASSERT
1956   static bool is_vm_complete() { return _vm_complete; }
1957 #endif
1958 
1959   // Verification
1960   static void verify();
1961   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
1962   static void print(bool print_stacks, bool internal_format) {
1963     // this function is only used by debug.cpp
1964     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
1965   }
1966   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
1967 
1968   // Get Java threads that are waiting to enter a monitor. If doLock
1969   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1970   // VM needs to be at a safepoint.
1971   static GrowableArray<JavaThread*>* get_pending_threads(int count,
1972     address monitor, bool doLock);
1973 
1974   // Get owning Java thread from the monitor's owner field. If doLock
1975   // is true, then Threads_lock is grabbed as needed. Otherwise, the
1976   // VM needs to be at a safepoint.
1977   static JavaThread *owning_thread_from_monitor_owner(address owner,
1978     bool doLock);
1979 
1980   // Number of threads on the active threads list
1981   static int number_of_threads()                 { return _number_of_threads; }
1982   // Number of non-daemon threads on the active threads list
1983   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
1984 
1985   // Deoptimizes all frames tied to marked nmethods
1986   static void deoptimized_wrt_marked_nmethods();
1987 
1988   static JavaThread* find_java_thread_from_java_tid(jlong java_tid);
1989 
1990 };
1991 
1992 
1993 // Thread iterator
1994 class ThreadClosure: public StackObj {
1995  public:
1996   virtual void do_thread(Thread* thread) = 0;
1997 };
1998 
1999 class SignalHandlerMark: public StackObj {
2000 private:
2001   Thread* _thread;
2002 public:
2003   SignalHandlerMark(Thread* t) {
2004     _thread = t;
2005     if (_thread) _thread->enter_signal_handler();
2006   }
2007   ~SignalHandlerMark() {
2008     if (_thread) _thread->leave_signal_handler();
2009     _thread = NULL;
2010   }
2011 };
2012 
2013 
2014 #endif // SHARE_VM_RUNTIME_THREAD_HPP