1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_THREAD_HPP
  26 #define SHARE_VM_RUNTIME_THREAD_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/threadLocalAllocBuffer.hpp"
  30 #include "oops/oop.hpp"
  31 #include "prims/jni.h"
  32 #include "prims/jvmtiExport.hpp"
  33 #include "runtime/frame.hpp"
  34 #include "runtime/javaFrameAnchor.hpp"
  35 #include "runtime/jniHandles.hpp"
  36 #include "runtime/mutexLocker.hpp"
  37 #include "runtime/os.hpp"
  38 #include "runtime/osThread.hpp"
  39 #include "runtime/park.hpp"
  40 #include "runtime/safepoint.hpp"
  41 #include "runtime/stubRoutines.hpp"
  42 #include "runtime/threadLocalStorage.hpp"
  43 #include "runtime/unhandledOops.hpp"
  44 #include "utilities/macros.hpp"
  45 
  46 #if INCLUDE_NMT
  47 #include "services/memRecorder.hpp"
  48 #endif // INCLUDE_NMT
  49 
  50 #include "trace/traceBackend.hpp"
  51 #include "trace/traceMacros.hpp"
  52 #include "utilities/exceptions.hpp"
  53 #include "utilities/top.hpp"
  54 #if INCLUDE_ALL_GCS
  55 #include "gc_implementation/g1/dirtyCardQueue.hpp"
  56 #include "gc_implementation/g1/satbQueue.hpp"
  57 #endif // INCLUDE_ALL_GCS
  58 #ifdef ZERO
  59 #ifdef TARGET_ARCH_zero
  60 # include "stack_zero.hpp"
  61 #endif
  62 #endif
  63 
  64 class ThreadSafepointState;
  65 class ThreadProfiler;
  66 
  67 class JvmtiThreadState;
  68 class JvmtiGetLoadedClassesClosure;
  69 class ThreadStatistics;
  70 class ConcurrentLocksDump;
  71 class ParkEvent;
  72 class Parker;
  73 
  74 class ciEnv;
  75 class CompileThread;
  76 class CompileLog;
  77 class CompileTask;
  78 class CompileQueue;
  79 class CompilerCounters;
  80 class vframeArray;
  81 
  82 class DeoptResourceMark;
  83 class jvmtiDeferredLocalVariableSet;
  84 
  85 class GCTaskQueue;
  86 class ThreadClosure;
  87 class IdealGraphPrinter;
  88 
  89 DEBUG_ONLY(class ResourceMark;)
  90 
  91 class WorkerThread;
  92 
  93 // Class hierarchy
  94 // - Thread
  95 //   - NamedThread
  96 //     - VMThread
  97 //     - ConcurrentGCThread
  98 //     - WorkerThread
  99 //       - GangWorker
 100 //       - GCTaskThread
 101 //   - JavaThread
 102 //   - WatcherThread
 103 
 104 class Thread: public ThreadShadow {
 105   friend class VMStructs;
 106  private:
 107   // Exception handling
 108   // (Note: _pending_exception and friends are in ThreadShadow)
 109   //oop       _pending_exception;                // pending exception for current thread
 110   // const char* _exception_file;                   // file information for exception (debugging only)
 111   // int         _exception_line;                   // line information for exception (debugging only)
 112  protected:
 113   // Support for forcing alignment of thread objects for biased locking
 114   void*       _real_malloc_address;
 115  public:
 116   void* operator new(size_t size) throw() { return allocate(size, true); }
 117   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 118     return allocate(size, false); }
 119   void  operator delete(void* p);
 120 
 121  protected:
 122    static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
 123  private:
 124 
 125   // ***************************************************************
 126   // Suspend and resume support
 127   // ***************************************************************
 128   //
 129   // VM suspend/resume no longer exists - it was once used for various
 130   // things including safepoints but was deprecated and finally removed
 131   // in Java 7. Because VM suspension was considered "internal" Java-level
 132   // suspension was considered "external", and this legacy naming scheme
 133   // remains.
 134   //
 135   // External suspend/resume requests come from JVM_SuspendThread,
 136   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
 137   // ResumeThread. External
 138   // suspend requests cause _external_suspend to be set and external
 139   // resume requests cause _external_suspend to be cleared.
 140   // External suspend requests do not nest on top of other external
 141   // suspend requests. The higher level APIs reject suspend requests
 142   // for already suspended threads.
 143   //
 144   // The external_suspend
 145   // flag is checked by has_special_runtime_exit_condition() and java thread
 146   // will self-suspend when handle_special_runtime_exit_condition() is
 147   // called. Most uses of the _thread_blocked state in JavaThreads are
 148   // considered the same as being externally suspended; if the blocking
 149   // condition lifts, the JavaThread will self-suspend. Other places
 150   // where VM checks for external_suspend include:
 151   //   + mutex granting (do not enter monitors when thread is suspended)
 152   //   + state transitions from _thread_in_native
 153   //
 154   // In general, java_suspend() does not wait for an external suspend
 155   // request to complete. When it returns, the only guarantee is that
 156   // the _external_suspend field is true.
 157   //
 158   // wait_for_ext_suspend_completion() is used to wait for an external
 159   // suspend request to complete. External suspend requests are usually
 160   // followed by some other interface call that requires the thread to
 161   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
 162   // the interface that requires quiescence, we give the JavaThread a
 163   // chance to self-suspend before we need it to be quiescent. This
 164   // improves overall suspend/query performance.
 165   //
 166   // _suspend_flags controls the behavior of java_ suspend/resume.
 167   // It must be set under the protection of SR_lock. Read from the flag is
 168   // OK without SR_lock as long as the value is only used as a hint.
 169   // (e.g., check _external_suspend first without lock and then recheck
 170   // inside SR_lock and finish the suspension)
 171   //
 172   // _suspend_flags is also overloaded for other "special conditions" so
 173   // that a single check indicates whether any special action is needed
 174   // eg. for async exceptions.
 175   // -------------------------------------------------------------------
 176   // Notes:
 177   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
 178   // but we still update its value to keep other part of the system (mainly
 179   // JVMTI) happy. ThreadState is legacy code (see notes in
 180   // osThread.hpp).
 181   //
 182   // 2. It would be more natural if set_external_suspend() is private and
 183   // part of java_suspend(), but that probably would affect the suspend/query
 184   // performance. Need more investigation on this.
 185   //
 186 
 187   // suspend/resume lock: used for self-suspend
 188   Monitor* _SR_lock;
 189 
 190  protected:
 191   enum SuspendFlags {
 192     // NOTE: avoid using the sign-bit as cc generates different test code
 193     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
 194 
 195     _external_suspend       = 0x20000000U, // thread is asked to self suspend
 196     _ext_suspended          = 0x40000000U, // thread has self-suspended
 197     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
 198 
 199     _has_async_exception    = 0x00000001U, // there is a pending async exception
 200     _critical_native_unlock = 0x00000002U  // Must call back to unlock JNI critical lock
 201   };
 202 
 203   // various suspension related flags - atomically updated
 204   // overloaded for async exception checking in check_special_condition_for_native_trans.
 205   volatile uint32_t _suspend_flags;
 206 
 207  private:
 208   int _num_nested_signal;
 209 
 210  public:
 211   void enter_signal_handler() { _num_nested_signal++; }
 212   void leave_signal_handler() { _num_nested_signal--; }
 213   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
 214 
 215  private:
 216   // Debug tracing
 217   static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
 218 
 219   // Active_handles points to a block of handles
 220   JNIHandleBlock* _active_handles;
 221 
 222   // One-element thread local free list
 223   JNIHandleBlock* _free_handle_block;
 224 
 225   // Point to the last handle mark
 226   HandleMark* _last_handle_mark;
 227 
 228   // The parity of the last strong_roots iteration in which this thread was
 229   // claimed as a task.
 230   jint _oops_do_parity;
 231 
 232   public:
 233    void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
 234    HandleMark* last_handle_mark() const          { return _last_handle_mark; }
 235   private:
 236 
 237   // debug support for checking if code does allow safepoints or not
 238   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
 239   // mutex, or blocking on an object synchronizer (Java locking).
 240   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
 241   // If !allow_allocation(), then an assertion failure will happen during allocation
 242   // (Hence, !allow_safepoint() => !allow_allocation()).
 243   //
 244   // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
 245   //
 246   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
 247   debug_only (int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
 248 
 249   // Used by SkipGCALot class.
 250   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
 251 
 252   // Record when GC is locked out via the GC_locker mechanism
 253   CHECK_UNHANDLED_OOPS_ONLY(int _gc_locked_out_count;)
 254 
 255   friend class No_Alloc_Verifier;
 256   friend class No_Safepoint_Verifier;
 257   friend class Pause_No_Safepoint_Verifier;
 258   friend class ThreadLocalStorage;
 259   friend class GC_locker;
 260 
 261   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
 262   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
 263                                                 // the Java heap
 264 
 265   TRACE_DATA _trace_data;                       // Thread-local data for tracing
 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   // Can this thread make Java upcalls
 325   virtual bool can_call_java() const                 { return true;  }
 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   bool is_gc_locked_out() { return _gc_locked_out_count > 0; }
 404 #endif // CHECK_UNHANDLED_OOPS
 405 
 406 #ifndef PRODUCT
 407   bool skip_gcalot()           { return _skip_gcalot; }
 408   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 409 #endif
 410 
 411  public:
 412   // Installs a pending exception to be inserted later
 413   static void send_async_exception(oop thread_oop, oop java_throwable);
 414 
 415   // Resource area
 416   ResourceArea* resource_area() const            { return _resource_area; }
 417   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
 418 
 419   OSThread* osthread() const                     { return _osthread;   }
 420   void set_osthread(OSThread* thread)            { _osthread = thread; }
 421 
 422   // JNI handle support
 423   JNIHandleBlock* active_handles() const         { return _active_handles; }
 424   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
 425   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
 426   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
 427 
 428   // Internal handle support
 429   HandleArea* handle_area() const                { return _handle_area; }
 430   void set_handle_area(HandleArea* area)         { _handle_area = area; }
 431 
 432   GrowableArray<Metadata*>* metadata_handles() const          { return _metadata_handles; }
 433   void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
 434 
 435   // Thread-Local Allocation Buffer (TLAB) support
 436   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
 437   void initialize_tlab() {
 438     if (UseTLAB) {
 439       tlab().initialize(this);
 440     }
 441   }
 442 
 443   jlong allocated_bytes()               { return _allocated_bytes; }
 444   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
 445   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
 446   jlong cooked_allocated_bytes() {
 447     jlong allocated_bytes = OrderAccess::load_acquire(&_allocated_bytes);
 448     if (UseTLAB) {
 449       size_t used_bytes = tlab().used_bytes();
 450       if ((ssize_t)used_bytes > 0) {
 451         // More-or-less valid tlab.  The load_acquire above should ensure
 452         // that the result of the add is <= the instantaneous value
 453         return allocated_bytes + used_bytes;
 454       }
 455     }
 456     return allocated_bytes;
 457   }
 458 
 459   TRACE_DATA* trace_data()              { return &_trace_data; }
 460 
 461   // VM operation support
 462   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
 463   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
 464   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
 465 
 466   // For tracking the heavyweight monitor the thread is pending on.
 467   ObjectMonitor* current_pending_monitor() {
 468     return _current_pending_monitor;
 469   }
 470   void set_current_pending_monitor(ObjectMonitor* monitor) {
 471     _current_pending_monitor = monitor;
 472   }
 473   void set_current_pending_monitor_is_from_java(bool from_java) {
 474     _current_pending_monitor_is_from_java = from_java;
 475   }
 476   bool current_pending_monitor_is_from_java() {
 477     return _current_pending_monitor_is_from_java;
 478   }
 479 
 480   // For tracking the ObjectMonitor on which this thread called Object.wait()
 481   ObjectMonitor* current_waiting_monitor() {
 482     return _current_waiting_monitor;
 483   }
 484   void set_current_waiting_monitor(ObjectMonitor* monitor) {
 485     _current_waiting_monitor = monitor;
 486   }
 487 
 488   // GC support
 489   // Apply "f->do_oop" to all root oops in "this".
 490   // Apply "cld_f->do_cld" to CLDs that are otherwise not kept alive.
 491   //   Used by JavaThread::oops_do.
 492   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
 493   virtual void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
 494 
 495   // Handles the parallel case for the method below.
 496 private:
 497   bool claim_oops_do_par_case(int collection_parity);
 498 public:
 499   // Requires that "collection_parity" is that of the current strong roots
 500   // iteration.  If "is_par" is false, sets the parity of "this" to
 501   // "collection_parity", and returns "true".  If "is_par" is true,
 502   // uses an atomic instruction to set the current threads parity to
 503   // "collection_parity", if it is not already.  Returns "true" iff the
 504   // calling thread does the update, this indicates that the calling thread
 505   // has claimed the thread's stack as a root groop in the current
 506   // collection.
 507   bool claim_oops_do(bool is_par, int collection_parity) {
 508     if (!is_par) {
 509       _oops_do_parity = collection_parity;
 510       return true;
 511     } else {
 512       return claim_oops_do_par_case(collection_parity);
 513     }
 514   }
 515 
 516   // Sweeper support
 517   void nmethods_do(CodeBlobClosure* cf);
 518 
 519   // jvmtiRedefineClasses support
 520   void metadata_do(void f(Metadata*));
 521 
 522   // Used by fast lock support
 523   virtual bool is_lock_owned(address adr) const;
 524 
 525   // Check if address is in the stack of the thread (not just for locks).
 526   // Warning: the method can only be used on the running thread
 527   bool is_in_stack(address adr) const;
 528   // Check if address is in the usable part of the stack (excludes protected
 529   // guard pages)
 530   bool is_in_usable_stack(address adr) const;
 531 
 532   // Sets this thread as starting thread. Returns failure if thread
 533   // creation fails due to lack of memory, too many threads etc.
 534   bool set_as_starting_thread();
 535 
 536  protected:
 537   // OS data associated with the thread
 538   OSThread* _osthread;  // Platform-specific thread information
 539 
 540   // Thread local resource area for temporary allocation within the VM
 541   ResourceArea* _resource_area;
 542 
 543   DEBUG_ONLY(ResourceMark* _current_resource_mark;)
 544 
 545   // Thread local handle area for allocation of handles within the VM
 546   HandleArea* _handle_area;
 547   GrowableArray<Metadata*>* _metadata_handles;
 548 
 549   // Support for stack overflow handling, get_thread, etc.
 550   address          _stack_base;
 551   size_t           _stack_size;
 552   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
 553   int              _lgrp_id;
 554 
 555  public:
 556   // Stack overflow support
 557   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
 558 
 559   void    set_stack_base(address base) { _stack_base = base; }
 560   size_t  stack_size() const           { return _stack_size; }
 561   void    set_stack_size(size_t size)  { _stack_size = size; }
 562   void    record_stack_base_and_size();
 563 
 564   bool    on_local_stack(address adr) const {
 565     /* QQQ this has knowledge of direction, ought to be a stack method */
 566     return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
 567   }
 568 
 569   uintptr_t self_raw_id()                    { return _self_raw_id; }
 570   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
 571 
 572   int     lgrp_id() const        { return _lgrp_id; }
 573   void    set_lgrp_id(int value) { _lgrp_id = value; }
 574 
 575   // Printing
 576   void print_on(outputStream* st) const;
 577   void print() const { print_on(tty); }
 578   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
 579 
 580   // Debug-only code
 581 #ifdef ASSERT
 582  private:
 583   // Deadlock detection support for Mutex locks. List of locks own by thread.
 584   Monitor* _owned_locks;
 585   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
 586   // thus the friendship
 587   friend class Mutex;
 588   friend class Monitor;
 589 
 590  public:
 591   void print_owned_locks_on(outputStream* st) const;
 592   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
 593   Monitor* owned_locks() const                   { return _owned_locks;          }
 594   bool owns_locks() const                        { return owned_locks() != NULL; }
 595   bool owns_locks_but_compiled_lock() const;
 596 
 597   // Deadlock detection
 598   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 599   ResourceMark* current_resource_mark()          { return _current_resource_mark; }
 600   void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
 601 #endif
 602 
 603   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
 604 
 605  private:
 606   volatile int _jvmti_env_iteration_count;
 607 
 608  public:
 609   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
 610   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
 611   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
 612 
 613   // Code generation
 614   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file   ); }
 615   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line   ); }
 616   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles   ); }
 617 
 618   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base ); }
 619   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size ); }
 620 
 621 #define TLAB_FIELD_OFFSET(name) \
 622   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
 623 
 624   TLAB_FIELD_OFFSET(start)
 625   TLAB_FIELD_OFFSET(end)
 626   TLAB_FIELD_OFFSET(top)
 627   TLAB_FIELD_OFFSET(pf_top)
 628   TLAB_FIELD_OFFSET(size)                   // desired_size
 629   TLAB_FIELD_OFFSET(refill_waste_limit)
 630   TLAB_FIELD_OFFSET(number_of_refills)
 631   TLAB_FIELD_OFFSET(fast_refill_waste)
 632   TLAB_FIELD_OFFSET(slow_allocations)
 633 
 634 #undef TLAB_FIELD_OFFSET
 635 
 636   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes ); }
 637 
 638  public:
 639   volatile intptr_t _Stalled ;
 640   volatile int _TypeTag ;
 641   ParkEvent * _ParkEvent ;                     // for synchronized()
 642   ParkEvent * _SleepEvent ;                    // for Thread.sleep
 643   ParkEvent * _MutexEvent ;                    // for native internal Mutex/Monitor
 644   ParkEvent * _MuxEvent ;                      // for low-level muxAcquire-muxRelease
 645   int NativeSyncRecursion ;                    // diagnostic
 646 
 647   volatile int _OnTrap ;                       // Resume-at IP delta
 648   jint _hashStateW ;                           // Marsaglia Shift-XOR thread-local RNG
 649   jint _hashStateX ;                           // thread-specific hashCode generator state
 650   jint _hashStateY ;
 651   jint _hashStateZ ;
 652   void * _schedctl ;
 653 
 654 
 655   volatile jint rng [4] ;                      // RNG for spin loop
 656 
 657   // Low-level leaf-lock primitives used to implement synchronization
 658   // and native monitor-mutex infrastructure.
 659   // Not for general synchronization use.
 660   static void SpinAcquire (volatile int * Lock, const char * Name) ;
 661   static void SpinRelease (volatile int * Lock) ;
 662   static void muxAcquire  (volatile intptr_t * Lock, const char * Name) ;
 663   static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
 664   static void muxRelease  (volatile intptr_t * Lock) ;
 665 };
 666 
 667 // Inline implementation of Thread::current()
 668 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
 669 // startup.
 670 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
 671 // period.   This is inlined in thread_<os_family>.inline.hpp.
 672 
 673 inline Thread* Thread::current() {
 674 #ifdef ASSERT
 675 // This function is very high traffic. Define PARANOID to enable expensive
 676 // asserts.
 677 #ifdef PARANOID
 678   // Signal handler should call ThreadLocalStorage::get_thread_slow()
 679   Thread* t = ThreadLocalStorage::get_thread_slow();
 680   assert(t != NULL && !t->is_inside_signal_handler(),
 681          "Don't use Thread::current() inside signal handler");
 682 #endif
 683 #endif
 684   Thread* thread = ThreadLocalStorage::thread();
 685   assert(thread != NULL, "just checking");
 686   return thread;
 687 }
 688 
 689 // Name support for threads.  non-JavaThread subclasses with multiple
 690 // uniquely named instances should derive from this.
 691 class NamedThread: public Thread {
 692   friend class VMStructs;
 693   enum {
 694     max_name_len = 64
 695   };
 696  private:
 697   char* _name;
 698   // log JavaThread being processed by oops_do
 699   JavaThread* _processed_thread;
 700 
 701  public:
 702   NamedThread();
 703   ~NamedThread();
 704   // May only be called once per thread.
 705   void set_name(const char* format, ...);
 706   virtual bool is_Named_thread() const { return true; }
 707   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
 708   JavaThread *processed_thread() { return _processed_thread; }
 709   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 710 };
 711 
 712 // Worker threads are named and have an id of an assigned work.
 713 class WorkerThread: public NamedThread {
 714 private:
 715   uint _id;
 716 public:
 717   WorkerThread() : _id(0)               { }
 718   virtual bool is_Worker_thread() const { return true; }
 719 
 720   virtual WorkerThread* as_Worker_thread() const {
 721     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
 722     return (WorkerThread*) this;
 723   }
 724 
 725   void set_id(uint work_id)             { _id = work_id; }
 726   uint id() const                       { return _id; }
 727 };
 728 
 729 // A single WatcherThread is used for simulating timer interrupts.
 730 class WatcherThread: public Thread {
 731   friend class VMStructs;
 732  public:
 733   virtual void run();
 734 
 735  private:
 736   static WatcherThread* _watcher_thread;
 737 
 738   static bool _startable;
 739   volatile static bool _should_terminate; // updated without holding lock
 740 
 741   os::WatcherThreadCrashProtection* _crash_protection;
 742  public:
 743   enum SomeConstants {
 744     delay_interval = 10                          // interrupt delay in milliseconds
 745   };
 746 
 747   // Constructor
 748   WatcherThread();
 749 
 750   // Tester
 751   bool is_Watcher_thread() const                 { return true; }
 752 
 753   // Printing
 754   char* name() const { return (char*)"VM Periodic Task Thread"; }
 755   void print_on(outputStream* st) const;
 756   void print() const { print_on(tty); }
 757   void unpark();
 758 
 759   // Returns the single instance of WatcherThread
 760   static WatcherThread* watcher_thread()         { return _watcher_thread; }
 761 
 762   // Create and start the single instance of WatcherThread, or stop it on shutdown
 763   static void start();
 764   static void stop();
 765   // Only allow start once the VM is sufficiently initialized
 766   // Otherwise the first task to enroll will trigger the start
 767   static void make_startable();
 768 
 769   void set_crash_protection(os::WatcherThreadCrashProtection* crash_protection) {
 770     assert(Thread::current()->is_Watcher_thread(), "Can only be set by WatcherThread");
 771     _crash_protection = crash_protection;
 772   }
 773 
 774   bool has_crash_protection() const { return _crash_protection != NULL; }
 775   os::WatcherThreadCrashProtection* crash_protection() const { return _crash_protection; }
 776 
 777  private:
 778   int sleep() const;
 779 };
 780 
 781 
 782 class CompilerThread;
 783 
 784 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 785 
 786 class JavaThread: public Thread {
 787   friend class VMStructs;
 788  private:
 789   JavaThread*    _next;                          // The next thread in the Threads list
 790   oop            _threadObj;                     // The Java level thread object
 791 
 792   // (thomaswue) Necessary for holding a compilation buffer.
 793   // Moved up from CompilerThread to JavaThread in order to enable code
 794   // installation from Java application code.
 795   BufferBlob*   _buffer_blob;
 796 #ifdef ASSERT
 797  private:
 798   int _java_call_counter;
 799 
 800  public:
 801   int  java_call_counter()                       { return _java_call_counter; }
 802   void inc_java_call_counter()                   { _java_call_counter++; }
 803   void dec_java_call_counter() {
 804     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
 805     _java_call_counter--;
 806   }
 807  private:  // restore original namespace restriction
 808 #endif  // ifdef ASSERT
 809 
 810 #ifndef PRODUCT
 811  public:
 812   enum {
 813     jump_ring_buffer_size = 16
 814   };
 815  private:  // restore original namespace restriction
 816 #endif
 817 
 818   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
 819 
 820   ThreadFunction _entry_point;
 821 
 822   JNIEnv        _jni_environment;
 823 
 824   // Deopt support
 825   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
 826 
 827   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
 828                                                  // transition out of native
 829   nmethod*       _deopt_nmethod;                 // nmethod that is currently being deoptimized
 830   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
 831   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
 832   // Because deoptimization is lazy we must save jvmti requests to set locals
 833   // in compiled frames until we deoptimize and we have an interpreter frame.
 834   // This holds the pointer to array (yeah like there might be more than one) of
 835   // description of compiled vframes that have locals that need to be updated.
 836   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
 837 
 838   // Handshake value for fixing 6243940. We need a place for the i2c
 839   // adapter to store the callee Method*. This value is NEVER live
 840   // across a gc point so it does NOT have to be gc'd
 841   // The handshake is open ended since we can't be certain that it will
 842   // be NULLed. This is because we rarely ever see the race and end up
 843   // in handle_wrong_method which is the backend of the handshake. See
 844   // code in i2c adapters and handle_wrong_method.
 845 
 846   Method*       _callee_target;
 847 
 848   // Used to pass back results to the interpreter or generated code running Java code.
 849   oop           _vm_result;    // oop result is GC-preserved
 850   Metadata*     _vm_result_2;  // non-oop result
 851 
 852   // See ReduceInitialCardMarks: this holds the precise space interval of
 853   // the most recent slow path allocation for which compiled code has
 854   // elided card-marks for performance along the fast-path.
 855   MemRegion     _deferred_card_mark;
 856 
 857   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
 858                                                  // allocated during deoptimization
 859                                                  // and by JNI_MonitorEnter/Exit
 860 
 861   // Async. requests support
 862   enum AsyncRequests {
 863     _no_async_condition = 0,
 864     _async_exception,
 865     _async_unsafe_access_error
 866   };
 867   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
 868   oop           _pending_async_exception;
 869 
 870   // Safepoint support
 871  public:                                         // Expose _thread_state for SafeFetchInt()
 872   volatile JavaThreadState _thread_state;
 873  private:
 874   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
 875   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
 876 
 877   // JavaThread termination support
 878   enum TerminatedTypes {
 879     _not_terminated = 0xDEAD - 2,
 880     _thread_exiting,                             // JavaThread::exit() has been called for this thread
 881     _thread_terminated,                          // JavaThread is removed from thread list
 882     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
 883                                                  // only VM_Exit can set _vm_exited
 884   };
 885 
 886   // In general a JavaThread's _terminated field transitions as follows:
 887   //
 888   //   _not_terminated => _thread_exiting => _thread_terminated
 889   //
 890   // _vm_exited is a special value to cover the case of a JavaThread
 891   // executing native code after the VM itself is terminated.
 892   volatile TerminatedTypes _terminated;
 893   // suspend/resume support
 894   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
 895   jint                  _in_deopt_handler;       // count of deoptimization
 896                                                  // handlers thread is in
 897   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
 898   bool                  _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
 899                                                  // never locked) when throwing an exception. Used by interpreter only.
 900 
 901   // JNI attach states:
 902   enum JNIAttachStates {
 903     _not_attaching_via_jni = 1,  // thread is not attaching via JNI
 904     _attaching_via_jni,          // thread is attaching via JNI
 905     _attached_via_jni            // thread has attached via JNI
 906   };
 907 
 908   // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
 909   // A native thread that is attaching via JNI starts with a value
 910   // of _attaching_via_jni and transitions to _attached_via_jni.
 911   volatile JNIAttachStates _jni_attach_state;
 912 
 913  public:
 914   // State of the stack guard pages for this thread.
 915   enum StackGuardState {
 916     stack_guard_unused,         // not needed
 917     stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
 918     stack_guard_enabled         // enabled
 919   };
 920 
 921  private:
 922 
 923 #ifdef GRAAL
 924   address   _graal_alternate_call_target;
 925   address   _graal_implicit_exception_pc;    // pc at which the most recent implicit exception occurred
 926 
 927   jlong*    _graal_counters;
 928 
 929  public:
 930   static jlong* _graal_old_thread_counters;
 931   static void collect_counters(typeArrayOop array);
 932  private:
 933 #endif // GRAAL
 934   StackGuardState        _stack_guard_state;
 935 
 936   nmethod*      _scanned_nmethod;  // nmethod being scanned by the sweeper
 937 
 938   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
 939   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
 940   // code)
 941   volatile oop     _exception_oop;               // Exception thrown in compiled code
 942   volatile address _exception_pc;                // PC where exception happened
 943   volatile address _exception_handler_pc;        // PC for handler of exception
 944   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
 945 
 946 #ifdef GRAAL
 947   // Record the method and bci from a gpu kernel exception so
 948   // it can be added into the exception stack trace
 949   jint    _gpu_exception_bci;
 950   Method* _gpu_exception_method;
 951   // Record the hsailDeoptimization info so gc oops_do processing can find it
 952   void*   _gpu_hsail_deopt_info;
 953   jint    _gpu_hsail_tlabs_count;
 954   ThreadLocalAllocBuffer** _gpu_hsail_tlabs;
 955 #endif
 956 
 957  public:
 958 #ifdef GRAAL
 959   void set_gpu_exception_bci(jint bci)           { _gpu_exception_bci = bci; } 
 960   jint get_gpu_exception_bci()                   { return _gpu_exception_bci; }
 961   void set_gpu_exception_method(Method* method)  { _gpu_exception_method = method; }
 962   Method* get_gpu_exception_method()             { return _gpu_exception_method; }
 963   void set_gpu_hsail_deopt_info(void * deoptInfo) { _gpu_hsail_deopt_info = deoptInfo; }
 964   void* get_gpu_hsail_deopt_info()               { return _gpu_hsail_deopt_info; }
 965   jint  get_gpu_hsail_tlabs_count()              { return _gpu_hsail_tlabs_count; }
 966 
 967   void  initialize_gpu_hsail_tlabs(jint count);
 968   ThreadLocalAllocBuffer* get_gpu_hsail_tlab_at(jint idx);
 969   void gpu_hsail_tlabs_make_parsable(bool retire);
 970   void  delete_gpu_hsail_tlabs();
 971 #endif
 972   
 973  private:  
 974   // support for JNI critical regions
 975   jint    _jni_active_critical;                  // count of entries into JNI critical region
 976 
 977   // For deadlock detection.
 978   int _depth_first_number;
 979 
 980   // JVMTI PopFrame support
 981   // This is set to popframe_pending to signal that top Java frame should be popped immediately
 982   int _popframe_condition;
 983 
 984 #ifndef PRODUCT
 985   int _jmp_ring_index;
 986   struct {
 987       // We use intptr_t instead of address so debugger doesn't try and display strings
 988       intptr_t _target;
 989       intptr_t _instruction;
 990       const char*  _file;
 991       int _line;
 992   }   _jmp_ring[ jump_ring_buffer_size ];
 993 #endif /* PRODUCT */
 994 
 995 #if INCLUDE_ALL_GCS
 996   // Support for G1 barriers
 997 
 998   ObjPtrQueue _satb_mark_queue;          // Thread-local log for SATB barrier.
 999   // Set of all such queues.
1000   static SATBMarkQueueSet _satb_mark_queue_set;
1001 
1002   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.
1003   // Set of all such queues.
1004   static DirtyCardQueueSet _dirty_card_queue_set;
1005 
1006   void flush_barrier_queues();
1007 #endif // INCLUDE_ALL_GCS
1008 
1009   friend class VMThread;
1010   friend class ThreadWaitTransition;
1011   friend class VM_Exit;
1012 
1013   void initialize();                             // Initialized the instance variables
1014 
1015  public:
1016   // Constructor
1017   JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1018   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1019   ~JavaThread();
1020 
1021 #ifdef ASSERT
1022   // verify this JavaThread hasn't be published in the Threads::list yet
1023   void verify_not_published();
1024 #endif
1025 
1026   //JNI functiontable getter/setter for JVMTI jni function table interception API.
1027   void set_jni_functions(struct JNINativeInterface_* functionTable) {
1028     _jni_environment.functions = functionTable;
1029   }
1030   struct JNINativeInterface_* get_jni_functions() {
1031     return (struct JNINativeInterface_ *)_jni_environment.functions;
1032   }
1033 
1034 
1035   BufferBlob*   get_buffer_blob()                { return _buffer_blob; }
1036   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
1037 
1038   // This function is called at thread creation to allow
1039   // platform specific thread variables to be initialized.
1040   void cache_global_variables();
1041 
1042   // Executes Shutdown.shutdown()
1043   void invoke_shutdown_hooks();
1044 
1045   // Cleanup on thread exit
1046   enum ExitType {
1047     normal_exit,
1048     jni_detach
1049   };
1050   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1051 
1052   void cleanup_failed_attach_current_thread();
1053 
1054   // Track the nmethod currently being scanned by the sweeper
1055   void          set_scanned_nmethod(nmethod* nm) {
1056     assert(_scanned_nmethod == NULL || nm == NULL, "should reset to NULL before writing a new value");
1057     _scanned_nmethod = nm;
1058   }
1059 
1060   // Testers
1061   virtual bool is_Java_thread() const            { return true;  }
1062 
1063   // Thread chain operations
1064   JavaThread* next() const                       { return _next; }
1065   void set_next(JavaThread* p)                   { _next = p; }
1066 
1067   // Thread oop. threadObj() can be NULL for initial JavaThread
1068   // (or for threads attached via JNI)
1069   oop threadObj() const                          { return _threadObj; }
1070   void set_threadObj(oop p)                      { _threadObj = p; }
1071 
1072   ThreadPriority java_priority() const;          // Read from threadObj()
1073 
1074   // Prepare thread and add to priority queue.  If a priority is
1075   // not specified, use the priority of the thread object. Threads_lock
1076   // must be held while this function is called.
1077   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1078 
1079   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
1080   address saved_exception_pc()                   { return _saved_exception_pc; }
1081 
1082 
1083   ThreadFunction entry_point() const             { return _entry_point; }
1084 
1085   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1086   void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
1087 
1088   // Last frame anchor routines
1089 
1090   JavaFrameAnchor* frame_anchor(void)                { return &_anchor; }
1091 
1092   // last_Java_sp
1093   bool has_last_Java_frame() const                   { return _anchor.has_last_Java_frame(); }
1094   intptr_t* last_Java_sp() const                     { return _anchor.last_Java_sp(); }
1095 
1096   // last_Java_pc
1097 
1098   address last_Java_pc(void)                         { return _anchor.last_Java_pc(); }
1099 
1100   // Safepoint support
1101   JavaThreadState thread_state() const           { return _thread_state; }
1102   void set_thread_state(JavaThreadState s)       { _thread_state=s;      }
1103   ThreadSafepointState *safepoint_state() const  { return _safepoint_state;  }
1104   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
1105   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
1106 
1107   // thread has called JavaThread::exit() or is terminated
1108   bool is_exiting()                              { return _terminated == _thread_exiting || is_terminated(); }
1109   // thread is terminated (no longer on the threads list); we compare
1110   // against the two non-terminated values so that a freed JavaThread
1111   // will also be considered terminated.
1112   bool is_terminated()                           { return _terminated != _not_terminated && _terminated != _thread_exiting; }
1113   void set_terminated(TerminatedTypes t)         { _terminated = t; }
1114   // special for Threads::remove() which is static:
1115   void set_terminated_value()                    { _terminated = _thread_terminated; }
1116   void block_if_vm_exited();
1117 
1118   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
1119   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
1120 
1121   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
1122   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1123 
1124 #if INCLUDE_NMT
1125   // native memory tracking
1126   inline MemRecorder* get_recorder() const          { return (MemRecorder*)_recorder; }
1127   inline void         set_recorder(MemRecorder* rc) { _recorder = rc; }
1128 
1129  private:
1130   // per-thread memory recorder
1131   MemRecorder* volatile _recorder;
1132 #endif // INCLUDE_NMT
1133 
1134   // Suspend/resume support for JavaThread
1135  private:
1136   void set_ext_suspended()       { set_suspend_flag (_ext_suspended);  }
1137   void clear_ext_suspended()     { clear_suspend_flag(_ext_suspended); }
1138 
1139  public:
1140   void java_suspend();
1141   void java_resume();
1142   int  java_suspend_self();
1143 
1144   void check_and_wait_while_suspended() {
1145     assert(JavaThread::current() == this, "sanity check");
1146 
1147     bool do_self_suspend;
1148     do {
1149       // were we externally suspended while we were waiting?
1150       do_self_suspend = handle_special_suspend_equivalent_condition();
1151       if (do_self_suspend) {
1152         // don't surprise the thread that suspended us by returning
1153         java_suspend_self();
1154         set_suspend_equivalent();
1155       }
1156     } while (do_self_suspend);
1157   }
1158   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1159   // Check for async exception in addition to safepoint and suspend request.
1160   static void check_special_condition_for_native_trans(JavaThread *thread);
1161 
1162   // Same as check_special_condition_for_native_trans but finishes the
1163   // transition into thread_in_Java mode so that it can potentially
1164   // block.
1165   static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1166 
1167   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1168   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1169     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1170     // Warning: is_ext_suspend_completed() may temporarily drop the
1171     // SR_lock to allow the thread to reach a stable thread state if
1172     // it is currently in a transient thread state.
1173     return is_ext_suspend_completed(false /*!called_by_wait */,
1174                                     SuspendRetryDelay, bits);
1175   }
1176 
1177   // We cannot allow wait_for_ext_suspend_completion() to run forever or
1178   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1179   // passed as the count and delay parameters. Experiments with specific
1180   // calls to wait_for_ext_suspend_completion() can be done by passing
1181   // other values in the code. Experiments with all calls can be done
1182   // via the appropriate -XX options.
1183   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1184 
1185   void set_external_suspend()     { set_suspend_flag  (_external_suspend); }
1186   void clear_external_suspend()   { clear_suspend_flag(_external_suspend); }
1187 
1188   void set_deopt_suspend()        { set_suspend_flag  (_deopt_suspend); }
1189   void clear_deopt_suspend()      { clear_suspend_flag(_deopt_suspend); }
1190   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
1191 
1192   bool is_external_suspend() const {
1193     return (_suspend_flags & _external_suspend) != 0;
1194   }
1195   // Whenever a thread transitions from native to vm/java it must suspend
1196   // if external|deopt suspend is present.
1197   bool is_suspend_after_native() const {
1198     return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
1199   }
1200 
1201   // external suspend request is completed
1202   bool is_ext_suspended() const {
1203     return (_suspend_flags & _ext_suspended) != 0;
1204   }
1205 
1206   bool is_external_suspend_with_lock() const {
1207     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1208     return is_external_suspend();
1209   }
1210 
1211   // Special method to handle a pending external suspend request
1212   // when a suspend equivalent condition lifts.
1213   bool handle_special_suspend_equivalent_condition() {
1214     assert(is_suspend_equivalent(),
1215       "should only be called in a suspend equivalence condition");
1216     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1217     bool ret = is_external_suspend();
1218     if (!ret) {
1219       // not about to self-suspend so clear suspend equivalence
1220       clear_suspend_equivalent();
1221     }
1222     // implied else:
1223     // We have a pending external suspend request so we leave the
1224     // suspend_equivalent flag set until java_suspend_self() sets
1225     // the ext_suspended flag and clears the suspend_equivalent
1226     // flag. This insures that wait_for_ext_suspend_completion()
1227     // will return consistent values.
1228     return ret;
1229   }
1230 
1231   // utility methods to see if we are doing some kind of suspension
1232   bool is_being_ext_suspended() const            {
1233     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1234     return is_ext_suspended() || is_external_suspend();
1235   }
1236 
1237   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
1238 
1239   void set_suspend_equivalent()                  { _suspend_equivalent = true; };
1240   void clear_suspend_equivalent()                { _suspend_equivalent = false; };
1241 
1242   // Thread.stop support
1243   void send_thread_stop(oop throwable);
1244   AsyncRequests clear_special_runtime_exit_condition() {
1245     AsyncRequests x = _special_runtime_exit_condition;
1246     _special_runtime_exit_condition = _no_async_condition;
1247     return x;
1248   }
1249 
1250   // Are any async conditions present?
1251   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1252 
1253   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1254 
1255   // these next two are also used for self-suspension and async exception support
1256   void handle_special_runtime_exit_condition(bool check_asyncs = true);
1257 
1258   // Return true if JavaThread has an asynchronous condition or
1259   // if external suspension is requested.
1260   bool has_special_runtime_exit_condition() {
1261     // We call is_external_suspend() last since external suspend should
1262     // be less common. Because we don't use is_external_suspend_with_lock
1263     // it is possible that we won't see an asynchronous external suspend
1264     // request that has just gotten started, i.e., SR_lock grabbed but
1265     // _external_suspend field change either not made yet or not visible
1266     // yet. However, this is okay because the request is asynchronous and
1267     // we will see the new flag value the next time through. It's also
1268     // possible that the external suspend request is dropped after
1269     // we have checked is_external_suspend(), we will recheck its value
1270     // under SR_lock in java_suspend_self().
1271     return (_special_runtime_exit_condition != _no_async_condition) ||
1272             is_external_suspend() || is_deopt_suspend();
1273   }
1274 
1275   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
1276 
1277   void set_pending_async_exception(oop e) {
1278     _pending_async_exception = e;
1279     _special_runtime_exit_condition = _async_exception;
1280     set_has_async_exception();
1281   }
1282 
1283   // Fast-locking support
1284   bool is_lock_owned(address adr) const;
1285 
1286   // Accessors for vframe array top
1287   // The linked list of vframe arrays are sorted on sp. This means when we
1288   // unpack the head must contain the vframe array to unpack.
1289   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1290   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
1291 
1292   // Side structure for defering update of java frame locals until deopt occurs
1293   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1294   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1295 
1296   // These only really exist to make debugging deopt problems simpler
1297 
1298   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1299   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
1300 
1301   // The special resourceMark used during deoptimization
1302 
1303   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
1304   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
1305 
1306   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
1307   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
1308   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
1309 
1310   void set_deopt_nmethod(nmethod* nm)            { _deopt_nmethod = nm;   }
1311   nmethod* deopt_nmethod()                       { return _deopt_nmethod; }
1312 
1313   Method*    callee_target() const               { return _callee_target; }
1314   void set_callee_target  (Method* x)          { _callee_target   = x; }
1315 
1316   // Oop results of vm runtime calls
1317   oop  vm_result() const                         { return _vm_result; }
1318   void set_vm_result  (oop x)                    { _vm_result   = x; }
1319 
1320   Metadata*    vm_result_2() const               { return _vm_result_2; }
1321   void set_vm_result_2  (Metadata* x)          { _vm_result_2   = x; }
1322 
1323   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
1324   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
1325 
1326 #ifdef GRAAL
1327   void set_graal_alternate_call_target(address a) { _graal_alternate_call_target = a; }
1328   void set_graal_implicit_exception_pc(address a) { _graal_implicit_exception_pc = a; }
1329 #endif
1330 
1331   // Exception handling for compiled methods
1332   oop      exception_oop() const                 { return _exception_oop; }
1333   address  exception_pc() const                  { return _exception_pc; }
1334   address  exception_handler_pc() const          { return _exception_handler_pc; }
1335   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
1336 
1337   void set_exception_oop(oop o)                  { (void)const_cast<oop&>(_exception_oop = o); }
1338   void set_exception_pc(address a)               { _exception_pc = a; }
1339   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
1340   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
1341 
1342   void clear_exception_oop_and_pc() {
1343     set_exception_oop(NULL);
1344     set_exception_pc(NULL);
1345   }
1346 
1347   // Stack overflow support
1348   inline size_t stack_available(address cur_sp);
1349   address stack_yellow_zone_base()
1350     { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
1351   size_t  stack_yellow_zone_size()
1352     { return StackYellowPages * os::vm_page_size(); }
1353   address stack_red_zone_base()
1354     { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
1355   size_t stack_red_zone_size()
1356     { return StackRedPages * os::vm_page_size(); }
1357   bool in_stack_yellow_zone(address a)
1358     { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
1359   bool in_stack_red_zone(address a)
1360     { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
1361 
1362   void create_stack_guard_pages();
1363   void remove_stack_guard_pages();
1364 
1365   void enable_stack_yellow_zone();
1366   void disable_stack_yellow_zone();
1367   void enable_stack_red_zone();
1368   void disable_stack_red_zone();
1369 
1370   inline bool stack_guard_zone_unused();
1371   inline bool stack_yellow_zone_disabled();
1372   inline bool stack_yellow_zone_enabled();
1373 
1374   // Attempt to reguard the stack after a stack overflow may have occurred.
1375   // Returns true if (a) guard pages are not needed on this thread, (b) the
1376   // pages are already guarded, or (c) the pages were successfully reguarded.
1377   // Returns false if there is not enough stack space to reguard the pages, in
1378   // which case the caller should unwind a frame and try again.  The argument
1379   // should be the caller's (approximate) sp.
1380   bool reguard_stack(address cur_sp);
1381   // Similar to above but see if current stackpoint is out of the guard area
1382   // and reguard if possible.
1383   bool reguard_stack(void);
1384 
1385   // Misc. accessors/mutators
1386   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
1387   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
1388   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
1389 
1390 #ifndef PRODUCT
1391   void record_jump(address target, address instr, const char* file, int line);
1392 #endif /* PRODUCT */
1393 
1394   // For assembly stub generation
1395   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj           ); }
1396 #ifndef PRODUCT
1397   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index      ); }
1398   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring            ); }
1399 #endif /* PRODUCT */
1400   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment     ); }
1401   static ByteSize last_Java_sp_offset()          {
1402     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1403   }
1404   static ByteSize last_Java_pc_offset()          {
1405     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1406   }
1407   static ByteSize frame_anchor_offset()          {
1408     return byte_offset_of(JavaThread, _anchor);
1409   }
1410   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target       ); }
1411   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result           ); }
1412   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2         ); }
1413   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state        ); }
1414   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
1415   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
1416 #ifdef GRAAL
1417   static ByteSize graal_alternate_call_target_offset() { return byte_offset_of(JavaThread, _graal_alternate_call_target); }
1418   static ByteSize graal_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _graal_implicit_exception_pc); }
1419   static ByteSize graal_counters_offset()        { return byte_offset_of(JavaThread, _graal_counters      ); }
1420 #endif // GRAAL
1421   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
1422   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
1423   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
1424   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1425   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
1426   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
1427 
1428   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1429   static ByteSize should_post_on_exceptions_flag_offset() {
1430     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1431   }
1432 
1433 #if INCLUDE_ALL_GCS
1434   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
1435   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
1436 #endif // INCLUDE_ALL_GCS
1437 
1438   // Returns the jni environment for this thread
1439   JNIEnv* jni_environment()                      { return &_jni_environment; }
1440 
1441   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1442     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1443     // Only return NULL if thread is off the thread list; starting to
1444     // exit should not return NULL.
1445     if (thread_from_jni_env->is_terminated()) {
1446        thread_from_jni_env->block_if_vm_exited();
1447        return NULL;
1448     } else {
1449        return thread_from_jni_env;
1450     }
1451   }
1452 
1453   // JNI critical regions. These can nest.
1454   bool in_critical()    { return _jni_active_critical > 0; }
1455   bool in_last_critical()  { return _jni_active_critical == 1; }
1456   void enter_critical() { assert(Thread::current() == this ||
1457                                  Thread::current()->is_VM_thread() && SafepointSynchronize::is_synchronizing(),
1458                                  "this must be current thread or synchronizing");
1459                           _jni_active_critical++; }
1460   void exit_critical()  { assert(Thread::current() == this,
1461                                  "this must be current thread");
1462                           _jni_active_critical--;
1463                           assert(_jni_active_critical >= 0,
1464                                  "JNI critical nesting problem?"); }
1465 
1466   // For deadlock detection
1467   int depth_first_number() { return _depth_first_number; }
1468   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1469 
1470  private:
1471   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1472 
1473  public:
1474   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
1475   void add_monitor_chunk(MonitorChunk* chunk);
1476   void remove_monitor_chunk(MonitorChunk* chunk);
1477   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
1478   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
1479   void dec_in_deopt_handler()                    {
1480     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1481     if (_in_deopt_handler > 0) { // robustness
1482       _in_deopt_handler--;
1483     }
1484   }
1485 
1486  private:
1487   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1488 
1489  public:
1490 
1491   // Frame iteration; calls the function f for all frames on the stack
1492   void frames_do(void f(frame*, const RegisterMap*));
1493 
1494   // Memory operations
1495   void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1496 
1497   // Sweeper operations
1498   void nmethods_do(CodeBlobClosure* cf);
1499 
1500   // RedefineClasses Support
1501   void metadata_do(void f(Metadata*));
1502 
1503   // Memory management operations
1504   void gc_epilogue();
1505   void gc_prologue();
1506 
1507   // Misc. operations
1508   char* name() const { return (char*)get_thread_name(); }
1509   void print_on(outputStream* st) const;
1510   void print() const { print_on(tty); }
1511   void print_value();
1512   void print_thread_state_on(outputStream* ) const      PRODUCT_RETURN;
1513   void print_thread_state() const                       PRODUCT_RETURN;
1514   void print_on_error(outputStream* st, char* buf, int buflen) const;
1515   void verify();
1516   const char* get_thread_name() const;
1517 private:
1518   // factor out low-level mechanics for use in both normal and error cases
1519   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1520 public:
1521   const char* get_threadgroup_name() const;
1522   const char* get_parent_name() const;
1523 
1524   // Accessing frames
1525   frame last_frame() {
1526     _anchor.make_walkable(this);
1527     return pd_last_frame();
1528   }
1529   javaVFrame* last_java_vframe(RegisterMap* reg_map);
1530 
1531   // Returns method at 'depth' java or native frames down the stack
1532   // Used for security checks
1533   Klass* security_get_caller_class(int depth);
1534 
1535   // Print stack trace in external format
1536   void print_stack_on(outputStream* st);
1537   void print_stack() { print_stack_on(tty); }
1538 
1539   // Print stack traces in various internal formats
1540   void trace_stack()                             PRODUCT_RETURN;
1541   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
1542   void trace_frames()                            PRODUCT_RETURN;
1543   void trace_oops()                              PRODUCT_RETURN;
1544 
1545   // Print an annotated view of the stack frames
1546   void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1547   void validate_frame_layout() {
1548     print_frame_layout(0, true);
1549   }
1550 
1551   // Returns the number of stack frames on the stack
1552   int depth() const;
1553 
1554   // Function for testing deoptimization
1555   void deoptimize();
1556   void make_zombies();
1557 
1558   void deoptimized_wrt_marked_nmethods();
1559 
1560   // Profiling operation (see fprofile.cpp)
1561  public:
1562    bool profile_last_Java_frame(frame* fr);
1563 
1564  private:
1565    ThreadProfiler* _thread_profiler;
1566  private:
1567    friend class FlatProfiler;                    // uses both [gs]et_thread_profiler.
1568    friend class FlatProfilerTask;                // uses get_thread_profiler.
1569    friend class ThreadProfilerMark;              // uses get_thread_profiler.
1570    ThreadProfiler* get_thread_profiler()         { return _thread_profiler; }
1571    ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
1572      ThreadProfiler* result = _thread_profiler;
1573      _thread_profiler = tp;
1574      return result;
1575    }
1576 
1577  // NMT (Native memory tracking) support.
1578  // This flag helps NMT to determine if this JavaThread will be blocked
1579  // at safepoint. If not, ThreadCritical is needed for writing memory records.
1580  // JavaThread is only safepoint visible when it is in Threads' thread list,
1581  // it is not visible until it is added to the list and becomes invisible
1582  // once it is removed from the list.
1583  public:
1584   bool is_safepoint_visible() const { return _safepoint_visible; }
1585   void set_safepoint_visible(bool visible) { _safepoint_visible = visible; }
1586  private:
1587   bool _safepoint_visible;
1588 
1589   // Static operations
1590  public:
1591   // Returns the running thread as a JavaThread
1592   static inline JavaThread* current();
1593 
1594   // Returns the active Java thread.  Do not use this if you know you are calling
1595   // from a JavaThread, as it's slower than JavaThread::current.  If called from
1596   // the VMThread, it also returns the JavaThread that instigated the VMThread's
1597   // operation.  You may not want that either.
1598   static JavaThread* active();
1599 
1600   inline CompilerThread* as_CompilerThread();
1601 
1602  public:
1603   virtual void run();
1604   void thread_main_inner();
1605 
1606  private:
1607   // PRIVILEGED STACK
1608   PrivilegedElement*  _privileged_stack_top;
1609   GrowableArray<oop>* _array_for_gc;
1610  public:
1611 
1612   // Returns the privileged_stack information.
1613   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
1614   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
1615   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1616 
1617  public:
1618   // Thread local information maintained by JVMTI.
1619   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
1620   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1621   // getter is used to get this JavaThread's JvmtiThreadState if it has
1622   // one which means NULL can be returned. JvmtiThreadState::state_for()
1623   // is used to get the specified JavaThread's JvmtiThreadState if it has
1624   // one or it allocates a new JvmtiThreadState for the JavaThread and
1625   // returns it. JvmtiThreadState::state_for() will return NULL only if
1626   // the specified JavaThread is exiting.
1627   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
1628   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1629   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1630   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
1631 
1632   // JVMTI PopFrame support
1633   // Setting and clearing popframe_condition
1634   // All of these enumerated values are bits. popframe_pending
1635   // indicates that a PopFrame() has been requested and not yet been
1636   // completed. popframe_processing indicates that that PopFrame() is in
1637   // the process of being completed. popframe_force_deopt_reexecution_bit
1638   // indicates that special handling is required when returning to a
1639   // deoptimized caller.
1640   enum PopCondition {
1641     popframe_inactive                      = 0x00,
1642     popframe_pending_bit                   = 0x01,
1643     popframe_processing_bit                = 0x02,
1644     popframe_force_deopt_reexecution_bit   = 0x04
1645   };
1646   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
1647   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
1648   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
1649   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
1650   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
1651   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
1652   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1653   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1654 #ifdef CC_INTERP
1655   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
1656   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
1657   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
1658   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
1659   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
1660 #endif
1661 
1662  private:
1663   // Saved incoming arguments to popped frame.
1664   // Used only when popped interpreted frame returns to deoptimized frame.
1665   void*    _popframe_preserved_args;
1666   int      _popframe_preserved_args_size;
1667 
1668  public:
1669   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
1670   void* popframe_preserved_args();
1671   ByteSize popframe_preserved_args_size();
1672   WordSize popframe_preserved_args_size_in_words();
1673   void  popframe_free_preserved_args();
1674 
1675 
1676  private:
1677   JvmtiThreadState *_jvmti_thread_state;
1678   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1679 
1680   // Used by the interpreter in fullspeed mode for frame pop, method
1681   // entry, method exit and single stepping support. This field is
1682   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1683   // It can be set to zero asynchronously (i.e., without a VM operation
1684   // or a lock) so we have to be very careful.
1685   int               _interp_only_mode;
1686 
1687  public:
1688   // used by the interpreter for fullspeed debugging support (see above)
1689   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1690   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
1691   int get_interp_only_mode()                { return _interp_only_mode; }
1692   void increment_interp_only_mode()         { ++_interp_only_mode; }
1693   void decrement_interp_only_mode()         { --_interp_only_mode; }
1694 
1695   // support for cached flag that indicates whether exceptions need to be posted for this thread
1696   // if this is false, we can avoid deoptimizing when events are thrown
1697   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1698  private:
1699   int    _should_post_on_exceptions_flag;
1700 
1701  public:
1702   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
1703   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
1704 
1705  private:
1706   ThreadStatistics *_thread_stat;
1707 
1708  public:
1709   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
1710 
1711   // Return a blocker object for which this thread is blocked parking.
1712   oop current_park_blocker();
1713 
1714  private:
1715   static size_t _stack_size_at_create;
1716 
1717  public:
1718   static inline size_t stack_size_at_create(void) {
1719     return _stack_size_at_create;
1720   }
1721   static inline void set_stack_size_at_create(size_t value) {
1722     _stack_size_at_create = value;
1723   }
1724 
1725 #if INCLUDE_ALL_GCS
1726   // SATB marking queue support
1727   ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
1728   static SATBMarkQueueSet& satb_mark_queue_set() {
1729     return _satb_mark_queue_set;
1730   }
1731 
1732   // Dirty card queue support
1733   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
1734   static DirtyCardQueueSet& dirty_card_queue_set() {
1735     return _dirty_card_queue_set;
1736   }
1737 #endif // INCLUDE_ALL_GCS
1738 
1739   // This method initializes the SATB and dirty card queues before a
1740   // JavaThread is added to the Java thread list. Right now, we don't
1741   // have to do anything to the dirty card queue (it should have been
1742   // activated when the thread was created), but we have to activate
1743   // the SATB queue if the thread is created while a marking cycle is
1744   // in progress. The activation / de-activation of the SATB queues at
1745   // the beginning / end of a marking cycle is done during safepoints
1746   // so we have to make sure this method is called outside one to be
1747   // able to safely read the active field of the SATB queue set. Right
1748   // now, it is called just before the thread is added to the Java
1749   // thread list in the Threads::add() method. That method is holding
1750   // the Threads_lock which ensures we are outside a safepoint. We
1751   // cannot do the obvious and set the active field of the SATB queue
1752   // when the thread is created given that, in some cases, safepoints
1753   // might happen between the JavaThread constructor being called and the
1754   // thread being added to the Java thread list (an example of this is
1755   // when the structure for the DestroyJavaVM thread is created).
1756 #if INCLUDE_ALL_GCS
1757   void initialize_queues();
1758 #else  // INCLUDE_ALL_GCS
1759   void initialize_queues() { }
1760 #endif // INCLUDE_ALL_GCS
1761 
1762   // Machine dependent stuff
1763 #ifdef TARGET_OS_ARCH_linux_x86
1764 # include "thread_linux_x86.hpp"
1765 #endif
1766 #ifdef TARGET_OS_ARCH_linux_sparc
1767 # include "thread_linux_sparc.hpp"
1768 #endif
1769 #ifdef TARGET_OS_ARCH_linux_zero
1770 # include "thread_linux_zero.hpp"
1771 #endif
1772 #ifdef TARGET_OS_ARCH_solaris_x86
1773 # include "thread_solaris_x86.hpp"
1774 #endif
1775 #ifdef TARGET_OS_ARCH_solaris_sparc
1776 # include "thread_solaris_sparc.hpp"
1777 #endif
1778 #ifdef TARGET_OS_ARCH_windows_x86
1779 # include "thread_windows_x86.hpp"
1780 #endif
1781 #ifdef TARGET_OS_ARCH_linux_arm
1782 # include "thread_linux_arm.hpp"
1783 #endif
1784 #ifdef TARGET_OS_ARCH_linux_ppc
1785 # include "thread_linux_ppc.hpp"
1786 #endif
1787 #ifdef TARGET_OS_ARCH_bsd_x86
1788 # include "thread_bsd_x86.hpp"
1789 #endif
1790 #ifdef TARGET_OS_ARCH_bsd_zero
1791 # include "thread_bsd_zero.hpp"
1792 #endif
1793 
1794 
1795  public:
1796   void set_blocked_on_compilation(bool value) {
1797     _blocked_on_compilation = value;
1798   }
1799 
1800   bool blocked_on_compilation() {
1801     return _blocked_on_compilation;
1802   }
1803  protected:
1804   bool         _blocked_on_compilation;
1805 
1806 
1807   // JSR166 per-thread parker
1808 private:
1809   Parker*    _parker;
1810 public:
1811   Parker*     parker() { return _parker; }
1812 
1813   // Biased locking support
1814 private:
1815   GrowableArray<MonitorInfo*>* _cached_monitor_info;
1816 public:
1817   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1818   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1819 
1820   // clearing/querying jni attach status
1821   bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1822   bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1823   void set_done_attaching_via_jni() { _jni_attach_state = _attached_via_jni; OrderAccess::fence(); }
1824 private:
1825   // This field is used to determine if a thread has claimed
1826   // a par_id: it is -1 if the thread has not claimed a par_id;
1827   // otherwise its value is the par_id that has been claimed.
1828   int _claimed_par_id;
1829 public:
1830   int get_claimed_par_id() { return _claimed_par_id; }
1831   void set_claimed_par_id(int id) { _claimed_par_id = id;}
1832 };
1833 
1834 // Inline implementation of JavaThread::current
1835 inline JavaThread* JavaThread::current() {
1836   Thread* thread = ThreadLocalStorage::thread();
1837   assert(thread != NULL && thread->is_Java_thread(), "just checking");
1838   return (JavaThread*)thread;
1839 }
1840 
1841 inline CompilerThread* JavaThread::as_CompilerThread() {
1842   assert(is_Compiler_thread(), "just checking");
1843   return (CompilerThread*)this;
1844 }
1845 
1846 inline bool JavaThread::stack_guard_zone_unused() {
1847   return _stack_guard_state == stack_guard_unused;
1848 }
1849 
1850 inline bool JavaThread::stack_yellow_zone_disabled() {
1851   return _stack_guard_state == stack_guard_yellow_disabled;
1852 }
1853 
1854 inline bool JavaThread::stack_yellow_zone_enabled() {
1855 #ifdef ASSERT
1856   if (os::uses_stack_guard_pages()) {
1857     assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
1858   }
1859 #endif
1860     return _stack_guard_state == stack_guard_enabled;
1861 }
1862 
1863 inline size_t JavaThread::stack_available(address cur_sp) {
1864   // This code assumes java stacks grow down
1865   address low_addr; // Limit on the address for deepest stack depth
1866   if ( _stack_guard_state == stack_guard_unused) {
1867     low_addr =  stack_base() - stack_size();
1868   } else {
1869     low_addr = stack_yellow_zone_base();
1870   }
1871   return cur_sp > low_addr ? cur_sp - low_addr : 0;
1872 }
1873 
1874 // A thread used for Compilation.
1875 class CompilerThread : public JavaThread {
1876   friend class VMStructs;
1877  private:
1878   CompilerCounters* _counters;
1879 
1880   ciEnv*            _env;
1881   CompileLog*       _log;
1882   CompileTask*      _task;
1883   CompileQueue*     _queue;
1884   BufferBlob*       _buffer_blob;
1885 
1886   nmethod*          _scanned_nmethod;  // nmethod being scanned by the sweeper
1887   AbstractCompiler* _compiler;
1888 
1889  public:
1890 
1891   static CompilerThread* current();
1892 
1893   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
1894 
1895   bool is_Compiler_thread() const                { return true; }
1896 
1897 #ifdef COMPILERGRAAL
1898   virtual bool can_call_java() const;
1899 #else
1900   virtual bool can_call_java() const             { return false; }
1901 #endif
1902 
1903   // Hide this compiler thread from external view.
1904   bool is_hidden_from_external_view() const      { return !can_call_java(); }
1905 
1906   void set_compiler(AbstractCompiler* c)         { _compiler = c; }
1907   AbstractCompiler* compiler() const             { return _compiler; }
1908 
1909   CompileQueue* queue()        const             { return _queue; }
1910   CompilerCounters* counters() const             { return _counters; }
1911 
1912   // Get/set the thread's compilation environment.
1913   ciEnv*        env()                            { return _env; }
1914   void          set_env(ciEnv* env)              { _env = env; }
1915 
1916   BufferBlob*   get_buffer_blob() const          { return _buffer_blob; }
1917   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
1918 
1919   // Get/set the thread's logging information
1920   CompileLog*   log()                            { return _log; }
1921   void          init_log(CompileLog* log) {
1922     // Set once, for good.
1923     assert(_log == NULL, "set only once");
1924     _log = log;
1925   }
1926 
1927   // GC support
1928   // Apply "f->do_oop" to all root oops in "this".
1929   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
1930   void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1931 
1932 #ifndef PRODUCT
1933 private:
1934   IdealGraphPrinter *_ideal_graph_printer;
1935 public:
1936   IdealGraphPrinter *ideal_graph_printer()                       { return _ideal_graph_printer; }
1937   void set_ideal_graph_printer(IdealGraphPrinter *n)             { _ideal_graph_printer = n; }
1938 #endif
1939 
1940   // Get/set the thread's current task
1941   CompileTask*  task()                           { return _task; }
1942   void          set_task(CompileTask* task)      { _task = task; }
1943 
1944   // Track the nmethod currently being scanned by the sweeper
1945   void          set_scanned_nmethod(nmethod* nm) {
1946     assert(_scanned_nmethod == NULL || nm == NULL, "should reset to NULL before writing a new value");
1947     _scanned_nmethod = nm;
1948   }
1949 };
1950 
1951 inline CompilerThread* CompilerThread::current() {
1952   return JavaThread::current()->as_CompilerThread();
1953 }
1954 
1955 
1956 // The active thread queue. It also keeps track of the current used
1957 // thread priorities.
1958 class Threads: AllStatic {
1959   friend class VMStructs;
1960  private:
1961   static JavaThread* _thread_list;
1962   static int         _number_of_threads;
1963   static int         _number_of_non_daemon_threads;
1964   static int         _return_code;
1965 #ifdef ASSERT
1966   static bool        _vm_complete;
1967 #endif
1968 
1969  public:
1970   // Thread management
1971   // force_daemon is a concession to JNI, where we may need to add a
1972   // thread to the thread list before allocating its thread object
1973   static void add(JavaThread* p, bool force_daemon = false);
1974   static void remove(JavaThread* p);
1975   static bool includes(JavaThread* p);
1976   static JavaThread* first()                     { return _thread_list; }
1977   static void threads_do(ThreadClosure* tc);
1978 
1979   // Initializes the vm and creates the vm thread
1980   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1981   static void convert_vm_init_libraries_to_agents();
1982   static void create_vm_init_libraries();
1983   static void create_vm_init_agents();
1984   static void shutdown_vm_agents();
1985   static bool destroy_vm();
1986   // Supported VM versions via JNI
1987   // Includes JNI_VERSION_1_1
1988   static jboolean is_supported_jni_version_including_1_1(jint version);
1989   // Does not include JNI_VERSION_1_1
1990   static jboolean is_supported_jni_version(jint version);
1991 
1992   // Garbage collection
1993   static void follow_other_roots(void f(oop*));
1994 
1995   // Apply "f->do_oop" to all root oops in all threads.
1996   // This version may only be called by sequential code.
1997   static void oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
1998   // This version may be called by sequential or parallel code.
1999   static void possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf);
2000   // This creates a list of GCTasks, one per thread.
2001   static void create_thread_roots_tasks(GCTaskQueue* q);
2002   // This creates a list of GCTasks, one per thread, for marking objects.
2003   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
2004 
2005   // Apply "f->do_oop" to roots in all threads that
2006   // are part of compiled frames
2007   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
2008 
2009   static void convert_hcode_pointers();
2010   static void restore_hcode_pointers();
2011 
2012   // Sweeper
2013   static void nmethods_do(CodeBlobClosure* cf);
2014 
2015   // RedefineClasses support
2016   static void metadata_do(void f(Metadata*));
2017 
2018   static void gc_epilogue();
2019   static void gc_prologue();
2020 #ifdef ASSERT
2021   static bool is_vm_complete() { return _vm_complete; }
2022 #endif
2023 
2024   // Verification
2025   static void verify();
2026   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
2027   static void print(bool print_stacks, bool internal_format) {
2028     // this function is only used by debug.cpp
2029     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
2030   }
2031   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2032 
2033   // Get Java threads that are waiting to enter a monitor. If doLock
2034   // is true, then Threads_lock is grabbed as needed. Otherwise, the
2035   // VM needs to be at a safepoint.
2036   static GrowableArray<JavaThread*>* get_pending_threads(int count,
2037     address monitor, bool doLock);
2038 
2039   // Get owning Java thread from the monitor's owner field. If doLock
2040   // is true, then Threads_lock is grabbed as needed. Otherwise, the
2041   // VM needs to be at a safepoint.
2042   static JavaThread *owning_thread_from_monitor_owner(address owner,
2043     bool doLock);
2044 
2045   // Number of threads on the active threads list
2046   static int number_of_threads()                 { return _number_of_threads; }
2047   // Number of non-daemon threads on the active threads list
2048   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
2049 
2050   // Deoptimizes all frames tied to marked nmethods
2051   static void deoptimized_wrt_marked_nmethods();
2052 
2053 };
2054 
2055 
2056 // Thread iterator
2057 class ThreadClosure: public StackObj {
2058  public:
2059   virtual void do_thread(Thread* thread) = 0;
2060 };
2061 
2062 class SignalHandlerMark: public StackObj {
2063 private:
2064   Thread* _thread;
2065 public:
2066   SignalHandlerMark(Thread* t) {
2067     _thread = t;
2068     if (_thread) _thread->enter_signal_handler();
2069   }
2070   ~SignalHandlerMark() {
2071     if (_thread) _thread->leave_signal_handler();
2072     _thread = NULL;
2073   }
2074 };
2075 
2076 
2077 #endif // SHARE_VM_RUNTIME_THREAD_HPP