jdk8-mips64-public/hotspot: src/share/vm/runtime/thread.hpp@f36c9fe788b8 (annotated)

src/share/vm/runtime/thread.hpp@f36c9fe788b8 (annotated)

src/share/vm/runtime/thread.hpp

Tue, 08 Feb 2011 09:11:37 -0800

author: mchung
date: Tue, 08 Feb 2011 09:11:37 -0800
changeset 2518: f36c9fe788b8
parent 2511: bf8517f4e4d0
child 2868: 2e038ad0c1d0
permissions: -rw-r--r--

7017673: Remove setting of the sun.jkernel.DownloadManager as a boot classloader hook
Reviewed-by: alanb, dcubed, coleenp

 /*
  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_RUNTIME_THREAD_HPP
 #define SHARE_VM_RUNTIME_THREAD_HPP
 #include "memory/allocation.hpp"
 #include "memory/threadLocalAllocBuffer.hpp"
 #include "oops/oop.hpp"
 #include "prims/jni.h"
 #include "prims/jvmtiExport.hpp"
 #include "runtime/frame.hpp"
 #include "runtime/javaFrameAnchor.hpp"
 #include "runtime/jniHandles.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
 #include "runtime/osThread.hpp"
 #include "runtime/park.hpp"
 #include "runtime/safepoint.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/threadLocalStorage.hpp"
 #include "runtime/unhandledOops.hpp"
 #include "utilities/exceptions.hpp"
 #include "utilities/top.hpp"
 #ifndef SERIALGC
 #include "gc_implementation/g1/dirtyCardQueue.hpp"
 #include "gc_implementation/g1/satbQueue.hpp"
 #endif
 #ifdef ZERO
 #ifdef TARGET_ARCH_zero
 # include "stack_zero.hpp"
 #endif
 #endif
 class ThreadSafepointState;
 class ThreadProfiler;
 class JvmtiThreadState;
 class JvmtiGetLoadedClassesClosure;
 class ThreadStatistics;
 class ConcurrentLocksDump;
 class ParkEvent;
 class Parker;
 class ciEnv;
 class CompileThread;
 class CompileLog;
 class CompileTask;
 class CompileQueue;
 class CompilerCounters;
 class vframeArray;
 class DeoptResourceMark;
 class jvmtiDeferredLocalVariableSet;
 class GCTaskQueue;
 class ThreadClosure;
 class IdealGraphPrinter;
 class WorkerThread;
 // Class hierarchy
 // - Thread
 //   - NamedThread
 //     - VMThread
 //     - ConcurrentGCThread
 //     - WorkerThread
 //       - GangWorker
 //       - GCTaskThread
 //   - JavaThread
 //   - WatcherThread
 class Thread: public ThreadShadow {
   friend class VMStructs;
  private:
   // Exception handling
   // (Note: _pending_exception and friends are in ThreadShadow)
   //oop       _pending_exception;                // pending exception for current thread
   // const char* _exception_file;                   // file information for exception (debugging only)
   // int         _exception_line;                   // line information for exception (debugging only)
   // Support for forcing alignment of thread objects for biased locking
   void*       _real_malloc_address;
  public:
   void* operator new(size_t size);
   void  operator delete(void* p);
  private:
   // ***************************************************************
   // Suspend and resume support
   // ***************************************************************
   //
   // VM suspend/resume no longer exists - it was once used for various
   // things including safepoints but was deprecated and finally removed
   // in Java 7. Because VM suspension was considered "internal" Java-level
   // suspension was considered "external", and this legacy naming scheme
   // remains.
   //
   // External suspend/resume requests come from JVM_SuspendThread,
   // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
   // ResumeThread. External
   // suspend requests cause _external_suspend to be set and external
   // resume requests cause _external_suspend to be cleared.
   // External suspend requests do not nest on top of other external
   // suspend requests. The higher level APIs reject suspend requests
   // for already suspended threads.
   //
   // The external_suspend
   // flag is checked by has_special_runtime_exit_condition() and java thread
   // will self-suspend when handle_special_runtime_exit_condition() is
   // called. Most uses of the _thread_blocked state in JavaThreads are
   // considered the same as being externally suspended; if the blocking
   // condition lifts, the JavaThread will self-suspend. Other places
   // where VM checks for external_suspend include:
   //   + mutex granting (do not enter monitors when thread is suspended)
   //   + state transitions from _thread_in_native
   //
   // In general, java_suspend() does not wait for an external suspend
   // request to complete. When it returns, the only guarantee is that
   // the _external_suspend field is true.
   //
   // wait_for_ext_suspend_completion() is used to wait for an external
   // suspend request to complete. External suspend requests are usually
   // followed by some other interface call that requires the thread to
   // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
   // the interface that requires quiescence, we give the JavaThread a
   // chance to self-suspend before we need it to be quiescent. This
   // improves overall suspend/query performance.
   //
   // _suspend_flags controls the behavior of java_ suspend/resume.
   // It must be set under the protection of SR_lock. Read from the flag is
   // OK without SR_lock as long as the value is only used as a hint.
   // (e.g., check _external_suspend first without lock and then recheck
   // inside SR_lock and finish the suspension)
   //
   // _suspend_flags is also overloaded for other "special conditions" so
   // that a single check indicates whether any special action is needed
   // eg. for async exceptions.
   // -------------------------------------------------------------------
   // Notes:
   // 1. The suspend/resume logic no longer uses ThreadState in OSThread
   // but we still update its value to keep other part of the system (mainly
   // JVMTI) happy. ThreadState is legacy code (see notes in
   // osThread.hpp).
   //
   // 2. It would be more natural if set_external_suspend() is private and
   // part of java_suspend(), but that probably would affect the suspend/query
   // performance. Need more investigation on this.
   //
   // suspend/resume lock: used for self-suspend
   Monitor* _SR_lock;
  protected:
   enum SuspendFlags {
     // NOTE: avoid using the sign-bit as cc generates different test code
     //       when the sign-bit is used, and sometimes incorrectly - see CR 6398077
     _external_suspend       = 0x20000000U, // thread is asked to self suspend
     _ext_suspended          = 0x40000000U, // thread has self-suspended
     _deopt_suspend          = 0x10000000U, // thread needs to self suspend for deopt
     _has_async_exception    = 0x00000001U  // there is a pending async exception
   };
   // various suspension related flags - atomically updated
   // overloaded for async exception checking in check_special_condition_for_native_trans.
   volatile uint32_t _suspend_flags;
  private:
   int _num_nested_signal;
  public:
   void enter_signal_handler() { _num_nested_signal++; }
   void leave_signal_handler() { _num_nested_signal--; }
   bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
  private:
   // Debug tracing
   static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
   // Active_handles points to a block of handles
   JNIHandleBlock* _active_handles;
   // One-element thread local free list
   JNIHandleBlock* _free_handle_block;
   // Point to the last handle mark
   HandleMark* _last_handle_mark;
   // The parity of the last strong_roots iteration in which this thread was
   // claimed as a task.
   jint _oops_do_parity;
   public:
    void set_last_handle_mark(HandleMark* mark)   { _last_handle_mark = mark; }
    HandleMark* last_handle_mark() const          { return _last_handle_mark; }
   private:
   // debug support for checking if code does allow safepoints or not
   // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
   // mutex, or blocking on an object synchronizer (Java locking).
   // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
   // If !allow_allocation(), then an assertion failure will happen during allocation
   // (Hence, !allow_safepoint() => !allow_allocation()).
   //
   // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
   //
   NOT_PRODUCT(int _allow_safepoint_count;)      // If 0, thread allow a safepoint to happen
   debug_only (int _allow_allocation_count;)     // If 0, the thread is allowed to allocate oops.
   // Used by SkipGCALot class.
   NOT_PRODUCT(bool _skip_gcalot;)               // Should we elide gc-a-lot?
   // Record when GC is locked out via the GC_locker mechanism
   CHECK_UNHANDLED_OOPS_ONLY(int _gc_locked_out_count;)
   friend class No_Alloc_Verifier;
   friend class No_Safepoint_Verifier;
   friend class Pause_No_Safepoint_Verifier;
   friend class ThreadLocalStorage;
   friend class GC_locker;
   ThreadLocalAllocBuffer _tlab;                 // Thread-local eden
   jlong _allocated_bytes;                       // Cumulative number of bytes allocated on
                                                 // the Java heap
   int   _vm_operation_started_count;            // VM_Operation support
   int   _vm_operation_completed_count;          // VM_Operation support
   ObjectMonitor* _current_pending_monitor;      // ObjectMonitor this thread
                                                 // is waiting to lock
   bool _current_pending_monitor_is_from_java;   // locking is from Java code
   // ObjectMonitor on which this thread called Object.wait()
   ObjectMonitor* _current_waiting_monitor;
   // Private thread-local objectmonitor list - a simple cache organized as a SLL.
  public:
   ObjectMonitor* omFreeList;
   int omFreeCount;                              // length of omFreeList
   int omFreeProvision;                          // reload chunk size
   ObjectMonitor* omInUseList;                   // SLL to track monitors in circulation
   int omInUseCount;                             // length of omInUseList
  public:
   enum {
     is_definitely_current_thread = true
   };
   // Constructor
   Thread();
   virtual ~Thread();
   // initializtion
   void initialize_thread_local_storage();
   // thread entry point
   virtual void run();
   // Testers
   virtual bool is_VM_thread()       const            { return false; }
   virtual bool is_Java_thread()     const            { return false; }
   virtual bool is_Compiler_thread() const            { return false; }
   virtual bool is_hidden_from_external_view() const  { return false; }
   virtual bool is_jvmti_agent_thread() const         { return false; }
   // True iff the thread can perform GC operations at a safepoint.
   // Generally will be true only of VM thread and parallel GC WorkGang
   // threads.
   virtual bool is_GC_task_thread() const             { return false; }
   virtual bool is_Watcher_thread() const             { return false; }
   virtual bool is_ConcurrentGC_thread() const        { return false; }
   virtual bool is_Named_thread() const               { return false; }
   virtual bool is_Worker_thread() const              { return false; }
   // Casts
   virtual WorkerThread* as_Worker_thread() const     { return NULL; }
   virtual char* name() const { return (char*)"Unknown thread"; }
   // Returns the current thread
   static inline Thread* current();
   // Common thread operations
   static void set_priority(Thread* thread, ThreadPriority priority);
   static ThreadPriority get_priority(const Thread* const thread);
   static void start(Thread* thread);
   static void interrupt(Thread* thr);
   static bool is_interrupted(Thread* thr, bool clear_interrupted);
   ObjectMonitor** omInUseList_addr()             { return (ObjectMonitor **)&omInUseList; }
   Monitor* SR_lock() const                       { return _SR_lock; }
   bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
   void set_suspend_flag(SuspendFlags f) {
     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
     uint32_t flags;
     do {
       flags = _suspend_flags;
     }
     while (Atomic::cmpxchg((jint)(flags | f),
                            (volatile jint*)&_suspend_flags,
                            (jint)flags) != (jint)flags);
   }
   void clear_suspend_flag(SuspendFlags f) {
     assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
     uint32_t flags;
     do {
       flags = _suspend_flags;
     }
     while (Atomic::cmpxchg((jint)(flags & ~f),
                            (volatile jint*)&_suspend_flags,
                            (jint)flags) != (jint)flags);
   }
   void set_has_async_exception() {
     set_suspend_flag(_has_async_exception);
   }
   void clear_has_async_exception() {
     clear_suspend_flag(_has_async_exception);
   }
   // Support for Unhandled Oop detection
 #ifdef CHECK_UNHANDLED_OOPS
  private:
   UnhandledOops* _unhandled_oops;
  public:
   UnhandledOops* unhandled_oops() { return _unhandled_oops; }
   // Mark oop safe for gc.  It may be stack allocated but won't move.
   void allow_unhandled_oop(oop *op) {
     if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
   }
   // Clear oops at safepoint so crashes point to unhandled oop violator
   void clear_unhandled_oops() {
     if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
   }
   bool is_gc_locked_out() { return _gc_locked_out_count > 0; }
 #endif // CHECK_UNHANDLED_OOPS
 #ifndef PRODUCT
   bool skip_gcalot()           { return _skip_gcalot; }
   void set_skip_gcalot(bool v) { _skip_gcalot = v;    }
 #endif
  public:
   // Installs a pending exception to be inserted later
   static void send_async_exception(oop thread_oop, oop java_throwable);
   // Resource area
   ResourceArea* resource_area() const            { return _resource_area; }
   void set_resource_area(ResourceArea* area)     { _resource_area = area; }
   OSThread* osthread() const                     { return _osthread;   }
   void set_osthread(OSThread* thread)            { _osthread = thread; }
   // JNI handle support
   JNIHandleBlock* active_handles() const         { return _active_handles; }
   void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
   JNIHandleBlock* free_handle_block() const      { return _free_handle_block; }
   void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
   // Internal handle support
   HandleArea* handle_area() const                { return _handle_area; }
   void set_handle_area(HandleArea* area)         { _handle_area = area; }
   // Thread-Local Allocation Buffer (TLAB) support
   ThreadLocalAllocBuffer& tlab()                 { return _tlab; }
   void initialize_tlab() {
     if (UseTLAB) {
       tlab().initialize();
     }
   }
   jlong allocated_bytes()               { return _allocated_bytes; }
   void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
   void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
   jlong cooked_allocated_bytes() {
     jlong allocated_bytes = OrderAccess::load_acquire(&_allocated_bytes);
     if (UseTLAB) {
       size_t used_bytes = tlab().used_bytes();
       if ((ssize_t)used_bytes > 0) {
         // More-or-less valid tlab.  The load_acquire above should ensure
         // that the result of the add is <= the instantaneous value
         return allocated_bytes + used_bytes;
       }
     }
     return allocated_bytes;
   }
   // VM operation support
   int vm_operation_ticket()                      { return ++_vm_operation_started_count; }
   int vm_operation_completed_count()             { return _vm_operation_completed_count; }
   void increment_vm_operation_completed_count()  { _vm_operation_completed_count++; }
   // For tracking the heavyweight monitor the thread is pending on.
   ObjectMonitor* current_pending_monitor() {
     return _current_pending_monitor;
   }
   void set_current_pending_monitor(ObjectMonitor* monitor) {
     _current_pending_monitor = monitor;
   }
   void set_current_pending_monitor_is_from_java(bool from_java) {
     _current_pending_monitor_is_from_java = from_java;
   }
   bool current_pending_monitor_is_from_java() {
     return _current_pending_monitor_is_from_java;
   }
   // For tracking the ObjectMonitor on which this thread called Object.wait()
   ObjectMonitor* current_waiting_monitor() {
     return _current_waiting_monitor;
   }
   void set_current_waiting_monitor(ObjectMonitor* monitor) {
     _current_waiting_monitor = monitor;
   }
   // GC support
   // Apply "f->do_oop" to all root oops in "this".
   // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
   void oops_do(OopClosure* f, CodeBlobClosure* cf);
   // Handles the parallel case for the method below.
 private:
   bool claim_oops_do_par_case(int collection_parity);
 public:
   // Requires that "collection_parity" is that of the current strong roots
   // iteration.  If "is_par" is false, sets the parity of "this" to
   // "collection_parity", and returns "true".  If "is_par" is true,
   // uses an atomic instruction to set the current threads parity to
   // "collection_parity", if it is not already.  Returns "true" iff the
   // calling thread does the update, this indicates that the calling thread
   // has claimed the thread's stack as a root groop in the current
   // collection.
   bool claim_oops_do(bool is_par, int collection_parity) {
     if (!is_par) {
       _oops_do_parity = collection_parity;
       return true;
     } else {
       return claim_oops_do_par_case(collection_parity);
     }
   }
   // Sweeper support
   void nmethods_do(CodeBlobClosure* cf);
   // Used by fast lock support
   virtual bool is_lock_owned(address adr) const;
   // Check if address is in the stack of the thread (not just for locks).
   // Warning: the method can only be used on the running thread
   bool is_in_stack(address adr) const;
   // Sets this thread as starting thread. Returns failure if thread
   // creation fails due to lack of memory, too many threads etc.
   bool set_as_starting_thread();
  protected:
   // OS data associated with the thread
   OSThread* _osthread;  // Platform-specific thread information
   // Thread local resource area for temporary allocation within the VM
   ResourceArea* _resource_area;
   // Thread local handle area for allocation of handles within the VM
   HandleArea* _handle_area;
   // Support for stack overflow handling, get_thread, etc.
   address          _stack_base;
   size_t           _stack_size;
   uintptr_t        _self_raw_id;      // used by get_thread (mutable)
   int              _lgrp_id;
  public:
   // Stack overflow support
   address stack_base() const           { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
   void    set_stack_base(address base) { _stack_base = base; }
   size_t  stack_size() const           { return _stack_size; }
   void    set_stack_size(size_t size)  { _stack_size = size; }
   void    record_stack_base_and_size();
   bool    on_local_stack(address adr) const {
     /* QQQ this has knowledge of direction, ought to be a stack method */
     return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
   }
   uintptr_t self_raw_id()                    { return _self_raw_id; }
   void      set_self_raw_id(uintptr_t value) { _self_raw_id = value; }
   int     lgrp_id() const        { return _lgrp_id; }
   void    set_lgrp_id(int value) { _lgrp_id = value; }
   // Printing
   void print_on(outputStream* st) const;
   void print() const { print_on(tty); }
   virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
   // Debug-only code
 #ifdef ASSERT
  private:
   // Deadlock detection support for Mutex locks. List of locks own by thread.
   Monitor* _owned_locks;
   // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
   // thus the friendship
   friend class Mutex;
   friend class Monitor;
  public:
   void print_owned_locks_on(outputStream* st) const;
   void print_owned_locks() const                 { print_owned_locks_on(tty);    }
   Monitor* owned_locks() const                   { return _owned_locks;          }
   bool owns_locks() const                        { return owned_locks() != NULL; }
   bool owns_locks_but_compiled_lock() const;
   // Deadlock detection
   bool allow_allocation()                        { return _allow_allocation_count == 0; }
 #endif
   void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
  private:
   volatile int _jvmti_env_iteration_count;
  public:
   void entering_jvmti_env_iteration()            { ++_jvmti_env_iteration_count; }
   void leaving_jvmti_env_iteration()             { --_jvmti_env_iteration_count; }
   bool is_inside_jvmti_env_iteration()           { return _jvmti_env_iteration_count > 0; }
   // Code generation
   static ByteSize exception_file_offset()        { return byte_offset_of(Thread, _exception_file   ); }
   static ByteSize exception_line_offset()        { return byte_offset_of(Thread, _exception_line   ); }
   static ByteSize active_handles_offset()        { return byte_offset_of(Thread, _active_handles   ); }
   static ByteSize stack_base_offset()            { return byte_offset_of(Thread, _stack_base ); }
   static ByteSize stack_size_offset()            { return byte_offset_of(Thread, _stack_size ); }
 #define TLAB_FIELD_OFFSET(name) \
   static ByteSize tlab_##name##_offset()         { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
   TLAB_FIELD_OFFSET(start)
   TLAB_FIELD_OFFSET(end)
   TLAB_FIELD_OFFSET(top)
   TLAB_FIELD_OFFSET(pf_top)
   TLAB_FIELD_OFFSET(size)                   // desired_size
   TLAB_FIELD_OFFSET(refill_waste_limit)
   TLAB_FIELD_OFFSET(number_of_refills)
   TLAB_FIELD_OFFSET(fast_refill_waste)
   TLAB_FIELD_OFFSET(slow_allocations)
 #undef TLAB_FIELD_OFFSET
   static ByteSize allocated_bytes_offset()       { return byte_offset_of(Thread, _allocated_bytes ); }
  public:
   volatile intptr_t _Stalled ;
   volatile int _TypeTag ;
   ParkEvent * _ParkEvent ;                     // for synchronized()
   ParkEvent * _SleepEvent ;                    // for Thread.sleep
   ParkEvent * _MutexEvent ;                    // for native internal Mutex/Monitor
   ParkEvent * _MuxEvent ;                      // for low-level muxAcquire-muxRelease
   int NativeSyncRecursion ;                    // diagnostic
   volatile int _OnTrap ;                       // Resume-at IP delta
   jint _hashStateW ;                           // Marsaglia Shift-XOR thread-local RNG
   jint _hashStateX ;                           // thread-specific hashCode generator state
   jint _hashStateY ;
   jint _hashStateZ ;
   void * _schedctl ;
   intptr_t _ScratchA, _ScratchB ;              // Scratch locations for fast-path sync code
   static ByteSize ScratchA_offset()            { return byte_offset_of(Thread, _ScratchA ); }
   static ByteSize ScratchB_offset()            { return byte_offset_of(Thread, _ScratchB ); }
   volatile jint rng [4] ;                      // RNG for spin loop
   // Low-level leaf-lock primitives used to implement synchronization
   // and native monitor-mutex infrastructure.
   // Not for general synchronization use.
   static void SpinAcquire (volatile int * Lock, const char * Name) ;
   static void SpinRelease (volatile int * Lock) ;
   static void muxAcquire  (volatile intptr_t * Lock, const char * Name) ;
   static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
   static void muxRelease  (volatile intptr_t * Lock) ;
 };
 // Inline implementation of Thread::current()
 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
 // startup.
 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
 // period.   This is inlined in thread_<os_family>.inline.hpp.
 inline Thread* Thread::current() {
 #ifdef ASSERT
 // This function is very high traffic. Define PARANOID to enable expensive
 // asserts.
 #ifdef PARANOID
   // Signal handler should call ThreadLocalStorage::get_thread_slow()
   Thread* t = ThreadLocalStorage::get_thread_slow();
   assert(t != NULL && !t->is_inside_signal_handler(),
          "Don't use Thread::current() inside signal handler");
 #endif
 #endif
   Thread* thread = ThreadLocalStorage::thread();
   assert(thread != NULL, "just checking");
   return thread;
 }
 // Name support for threads.  non-JavaThread subclasses with multiple
 // uniquely named instances should derive from this.
 class NamedThread: public Thread {
   friend class VMStructs;
   enum {
     max_name_len = 64
   };
  private:
   char* _name;
   // log JavaThread being processed by oops_do
   JavaThread* _processed_thread;
  public:
   NamedThread();
   ~NamedThread();
   // May only be called once per thread.
   void set_name(const char* format, ...);
   virtual bool is_Named_thread() const { return true; }
   virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
   JavaThread *processed_thread() { return _processed_thread; }
   void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
 };
 // Worker threads are named and have an id of an assigned work.
 class WorkerThread: public NamedThread {
 private:
   uint _id;
 public:
   WorkerThread() : _id(0)               { }
   virtual bool is_Worker_thread() const { return true; }
   virtual WorkerThread* as_Worker_thread() const {
     assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
     return (WorkerThread*) this;
   }
   void set_id(uint work_id)             { _id = work_id; }
   uint id() const                       { return _id; }
 };
 // A single WatcherThread is used for simulating timer interrupts.
 class WatcherThread: public Thread {
   friend class VMStructs;
  public:
   virtual void run();
  private:
   static WatcherThread* _watcher_thread;
   volatile static bool _should_terminate; // updated without holding lock
  public:
   enum SomeConstants {
     delay_interval = 10                          // interrupt delay in milliseconds
   };
   // Constructor
   WatcherThread();
   // Tester
   bool is_Watcher_thread() const                 { return true; }
   // Printing
   char* name() const { return (char*)"VM Periodic Task Thread"; }
   void print_on(outputStream* st) const;
   void print() const { print_on(tty); }
   // Returns the single instance of WatcherThread
   static WatcherThread* watcher_thread()         { return _watcher_thread; }
   // Create and start the single instance of WatcherThread, or stop it on shutdown
   static void start();
   static void stop();
 };
 class CompilerThread;
 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
 class JavaThread: public Thread {
   friend class VMStructs;
  private:
   JavaThread*    _next;                          // The next thread in the Threads list
   oop            _threadObj;                     // The Java level thread object
 #ifdef ASSERT
  private:
   int _java_call_counter;
  public:
   int  java_call_counter()                       { return _java_call_counter; }
   void inc_java_call_counter()                   { _java_call_counter++; }
   void dec_java_call_counter() {
     assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
     _java_call_counter--;
   }
  private:  // restore original namespace restriction
 #endif  // ifdef ASSERT
 #ifndef PRODUCT
  public:
   enum {
     jump_ring_buffer_size = 16
   };
  private:  // restore original namespace restriction
 #endif
   JavaFrameAnchor _anchor;                       // Encapsulation of current java frame and it state
   ThreadFunction _entry_point;
   JNIEnv        _jni_environment;
   // Deopt support
   DeoptResourceMark*  _deopt_mark;               // Holds special ResourceMark for deoptimization
   intptr_t*      _must_deopt_id;                 // id of frame that needs to be deopted once we
                                                  // transition out of native
   nmethod*       _deopt_nmethod;                 // nmethod that is currently being deoptimized
   vframeArray*  _vframe_array_head;              // Holds the heap of the active vframeArrays
   vframeArray*  _vframe_array_last;              // Holds last vFrameArray we popped
   // Because deoptimization is lazy we must save jvmti requests to set locals
   // in compiled frames until we deoptimize and we have an interpreter frame.
   // This holds the pointer to array (yeah like there might be more than one) of
   // description of compiled vframes that have locals that need to be updated.
   GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
   // Handshake value for fixing 6243940. We need a place for the i2c
   // adapter to store the callee methodOop. This value is NEVER live
   // across a gc point so it does NOT have to be gc'd
   // The handshake is open ended since we can't be certain that it will
   // be NULLed. This is because we rarely ever see the race and end up
   // in handle_wrong_method which is the backend of the handshake. See
   // code in i2c adapters and handle_wrong_method.
   methodOop     _callee_target;
   // Oop results of VM runtime calls
   oop           _vm_result;    // Used to pass back an oop result into Java code, GC-preserved
   oop           _vm_result_2;  // Used to pass back an oop result into Java code, GC-preserved
   // See ReduceInitialCardMarks: this holds the precise space interval of
   // the most recent slow path allocation for which compiled code has
   // elided card-marks for performance along the fast-path.
   MemRegion     _deferred_card_mark;
   MonitorChunk* _monitor_chunks;                 // Contains the off stack monitors
                                                  // allocated during deoptimization
                                                  // and by JNI_MonitorEnter/Exit
   // Async. requests support
   enum AsyncRequests {
     _no_async_condition = 0,
     _async_exception,
     _async_unsafe_access_error
   };
   AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
   oop           _pending_async_exception;
   // Safepoint support
  public:                                         // Expose _thread_state for SafeFetchInt()
   volatile JavaThreadState _thread_state;
  private:
   ThreadSafepointState *_safepoint_state;        // Holds information about a thread during a safepoint
   address               _saved_exception_pc;     // Saved pc of instruction where last implicit exception happened
   // JavaThread termination support
   enum TerminatedTypes {
     _not_terminated = 0xDEAD - 2,
     _thread_exiting,                             // JavaThread::exit() has been called for this thread
     _thread_terminated,                          // JavaThread is removed from thread list
     _vm_exited                                   // JavaThread is still executing native code, but VM is terminated
                                                  // only VM_Exit can set _vm_exited
   };
   // In general a JavaThread's _terminated field transitions as follows:
   //
   //   _not_terminated => _thread_exiting => _thread_terminated
   //
   // _vm_exited is a special value to cover the case of a JavaThread
   // executing native code after the VM itself is terminated.
   volatile TerminatedTypes _terminated;
   // suspend/resume support
   volatile bool         _suspend_equivalent;     // Suspend equivalent condition
   jint                  _in_deopt_handler;       // count of deoptimization
                                                  // handlers thread is in
   volatile bool         _doing_unsafe_access;    // Thread may fault due to unsafe access
   bool                  _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
                                                  // never locked) when throwing an exception. Used by interpreter only.
   //  Flag to mark a JNI thread in the process of attaching - See CR 6404306
   //  This flag is never set true other than at construction, and in that case
   //  is shortly thereafter set false
   volatile bool _is_attaching;
  public:
   // State of the stack guard pages for this thread.
   enum StackGuardState {
     stack_guard_unused,         // not needed
     stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
     stack_guard_enabled         // enabled
   };
  private:
   StackGuardState        _stack_guard_state;
   // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
   // used to temp. parsing values into and out of the runtime system during exception handling for compiled
   // code)
   volatile oop     _exception_oop;               // Exception thrown in compiled code
   volatile address _exception_pc;                // PC where exception happened
   volatile address _exception_handler_pc;        // PC for handler of exception
   volatile int     _exception_stack_size;        // Size of frame where exception happened
   volatile int     _is_method_handle_return;     // true (== 1) if the current exception PC is a MethodHandle call site.
   // support for compilation
   bool    _is_compiling;                         // is true if a compilation is active inthis thread (one compilation per thread possible)
   // support for JNI critical regions
   jint    _jni_active_critical;                  // count of entries into JNI critical region
   // For deadlock detection.
   int _depth_first_number;
   // JVMTI PopFrame support
   // This is set to popframe_pending to signal that top Java frame should be popped immediately
   int _popframe_condition;
 #ifndef PRODUCT
   int _jmp_ring_index;
   struct {
       // We use intptr_t instead of address so debugger doesn't try and display strings
       intptr_t _target;
       intptr_t _instruction;
       const char*  _file;
       int _line;
   }   _jmp_ring[ jump_ring_buffer_size ];
 #endif /* PRODUCT */
 #ifndef SERIALGC
   // Support for G1 barriers
   ObjPtrQueue _satb_mark_queue;          // Thread-local log for SATB barrier.
   // Set of all such queues.
   static SATBMarkQueueSet _satb_mark_queue_set;
   DirtyCardQueue _dirty_card_queue;      // Thread-local log for dirty cards.
   // Set of all such queues.
   static DirtyCardQueueSet _dirty_card_queue_set;
   void flush_barrier_queues();
 #endif // !SERIALGC
   friend class VMThread;
   friend class ThreadWaitTransition;
   friend class VM_Exit;
   void initialize();                             // Initialized the instance variables
  public:
   // Constructor
   JavaThread(bool is_attaching = false); // for main thread and JNI attached threads
   JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
   ~JavaThread();
 #ifdef ASSERT
   // verify this JavaThread hasn't be published in the Threads::list yet
   void verify_not_published();
 #endif
   //JNI functiontable getter/setter for JVMTI jni function table interception API.
   void set_jni_functions(struct JNINativeInterface_* functionTable) {
     _jni_environment.functions = functionTable;
   }
   struct JNINativeInterface_* get_jni_functions() {
     return (struct JNINativeInterface_ *)_jni_environment.functions;
   }
   // This function is called at thread creation to allow
   // platform specific thread variables to be initialized.
   void cache_global_variables();
   // Executes Shutdown.shutdown()
   void invoke_shutdown_hooks();
   // Cleanup on thread exit
   enum ExitType {
     normal_exit,
     jni_detach
   };
   void exit(bool destroy_vm, ExitType exit_type = normal_exit);
   void cleanup_failed_attach_current_thread();
   // Testers
   virtual bool is_Java_thread() const            { return true;  }
   // compilation
   void set_is_compiling(bool f)                  { _is_compiling = f; }
   bool is_compiling() const                      { return _is_compiling; }
   // Thread chain operations
   JavaThread* next() const                       { return _next; }
   void set_next(JavaThread* p)                   { _next = p; }
   // Thread oop. threadObj() can be NULL for initial JavaThread
   // (or for threads attached via JNI)
   oop threadObj() const                          { return _threadObj; }
   void set_threadObj(oop p)                      { _threadObj = p; }
   ThreadPriority java_priority() const;          // Read from threadObj()
   // Prepare thread and add to priority queue.  If a priority is
   // not specified, use the priority of the thread object. Threads_lock
   // must be held while this function is called.
   void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
   void set_saved_exception_pc(address pc)        { _saved_exception_pc = pc; }
   address saved_exception_pc()                   { return _saved_exception_pc; }
   ThreadFunction entry_point() const             { return _entry_point; }
   // Allocates a new Java level thread object for this thread. thread_name may be NULL.
   void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
   // Last frame anchor routines
   JavaFrameAnchor* frame_anchor(void)                { return &_anchor; }
   // last_Java_sp
   bool has_last_Java_frame() const                   { return _anchor.has_last_Java_frame(); }
   intptr_t* last_Java_sp() const                     { return _anchor.last_Java_sp(); }
   // last_Java_pc
   address last_Java_pc(void)                         { return _anchor.last_Java_pc(); }
   // Safepoint support
   JavaThreadState thread_state() const           { return _thread_state; }
   void set_thread_state(JavaThreadState s)       { _thread_state=s;      }
   ThreadSafepointState *safepoint_state() const  { return _safepoint_state;  }
   void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
   bool is_at_poll_safepoint()                    { return _safepoint_state->is_at_poll_safepoint(); }
   // thread has called JavaThread::exit() or is terminated
   bool is_exiting()                              { return _terminated == _thread_exiting || is_terminated(); }
   // thread is terminated (no longer on the threads list); we compare
   // against the two non-terminated values so that a freed JavaThread
   // will also be considered terminated.
   bool is_terminated()                           { return _terminated != _not_terminated && _terminated != _thread_exiting; }
   void set_terminated(TerminatedTypes t)         { _terminated = t; }
   // special for Threads::remove() which is static:
   void set_terminated_value()                    { _terminated = _thread_terminated; }
   void block_if_vm_exited();
   bool doing_unsafe_access()                     { return _doing_unsafe_access; }
   void set_doing_unsafe_access(bool val)         { _doing_unsafe_access = val; }
   bool do_not_unlock_if_synchronized()             { return _do_not_unlock_if_synchronized; }
   void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
   // Suspend/resume support for JavaThread
  private:
   void set_ext_suspended()       { set_suspend_flag (_ext_suspended);  }
   void clear_ext_suspended()     { clear_suspend_flag(_ext_suspended); }
  public:
   void java_suspend();
   void java_resume();
   int  java_suspend_self();
   void check_and_wait_while_suspended() {
     assert(JavaThread::current() == this, "sanity check");
     bool do_self_suspend;
     do {
       // were we externally suspended while we were waiting?
       do_self_suspend = handle_special_suspend_equivalent_condition();
       if (do_self_suspend) {
         // don't surprise the thread that suspended us by returning
         java_suspend_self();
         set_suspend_equivalent();
       }
     } while (do_self_suspend);
   }
   static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
   // Check for async exception in addition to safepoint and suspend request.
   static void check_special_condition_for_native_trans(JavaThread *thread);
   bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
   bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
     // Warning: is_ext_suspend_completed() may temporarily drop the
     // SR_lock to allow the thread to reach a stable thread state if
     // it is currently in a transient thread state.
     return is_ext_suspend_completed(false /*!called_by_wait */,
                                     SuspendRetryDelay, bits);
   }
   // We cannot allow wait_for_ext_suspend_completion() to run forever or
   // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
   // passed as the count and delay parameters. Experiments with specific
   // calls to wait_for_ext_suspend_completion() can be done by passing
   // other values in the code. Experiments with all calls can be done
   // via the appropriate -XX options.
   bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
   void set_external_suspend()     { set_suspend_flag  (_external_suspend); }
   void clear_external_suspend()   { clear_suspend_flag(_external_suspend); }
   void set_deopt_suspend()        { set_suspend_flag  (_deopt_suspend); }
   void clear_deopt_suspend()      { clear_suspend_flag(_deopt_suspend); }
   bool is_deopt_suspend()         { return (_suspend_flags & _deopt_suspend) != 0; }
   bool is_external_suspend() const {
     return (_suspend_flags & _external_suspend) != 0;
   }
   // Whenever a thread transitions from native to vm/java it must suspend
   // if external|deopt suspend is present.
   bool is_suspend_after_native() const {
     return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
   }
   // external suspend request is completed
   bool is_ext_suspended() const {
     return (_suspend_flags & _ext_suspended) != 0;
   }
   bool is_external_suspend_with_lock() const {
     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
     return is_external_suspend();
   }
   // Special method to handle a pending external suspend request
   // when a suspend equivalent condition lifts.
   bool handle_special_suspend_equivalent_condition() {
     assert(is_suspend_equivalent(),
       "should only be called in a suspend equivalence condition");
     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
     bool ret = is_external_suspend();
     if (!ret) {
       // not about to self-suspend so clear suspend equivalence
       clear_suspend_equivalent();
     }
     // implied else:
     // We have a pending external suspend request so we leave the
     // suspend_equivalent flag set until java_suspend_self() sets
     // the ext_suspended flag and clears the suspend_equivalent
     // flag. This insures that wait_for_ext_suspend_completion()
     // will return consistent values.
     return ret;
   }
   // utility methods to see if we are doing some kind of suspension
   bool is_being_ext_suspended() const            {
     MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
     return is_ext_suspended() || is_external_suspend();
   }
   bool is_suspend_equivalent() const             { return _suspend_equivalent; }
   void set_suspend_equivalent()                  { _suspend_equivalent = true; };
   void clear_suspend_equivalent()                { _suspend_equivalent = false; };
   // Thread.stop support
   void send_thread_stop(oop throwable);
   AsyncRequests clear_special_runtime_exit_condition() {
     AsyncRequests x = _special_runtime_exit_condition;
     _special_runtime_exit_condition = _no_async_condition;
     return x;
   }
   // Are any async conditions present?
   bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
   void check_and_handle_async_exceptions(bool check_unsafe_error = true);
   // these next two are also used for self-suspension and async exception support
   void handle_special_runtime_exit_condition(bool check_asyncs = true);
   // Return true if JavaThread has an asynchronous condition or
   // if external suspension is requested.
   bool has_special_runtime_exit_condition() {
     // We call is_external_suspend() last since external suspend should
     // be less common. Because we don't use is_external_suspend_with_lock
     // it is possible that we won't see an asynchronous external suspend
     // request that has just gotten started, i.e., SR_lock grabbed but
     // _external_suspend field change either not made yet or not visible
     // yet. However, this is okay because the request is asynchronous and
     // we will see the new flag value the next time through. It's also
     // possible that the external suspend request is dropped after
     // we have checked is_external_suspend(), we will recheck its value
     // under SR_lock in java_suspend_self().
     return (_special_runtime_exit_condition != _no_async_condition) ||
             is_external_suspend() || is_deopt_suspend();
   }
   void set_pending_unsafe_access_error()          { _special_runtime_exit_condition = _async_unsafe_access_error; }
   void set_pending_async_exception(oop e) {
     _pending_async_exception = e;
     _special_runtime_exit_condition = _async_exception;
     set_has_async_exception();
   }
   // Fast-locking support
   bool is_lock_owned(address adr) const;
   // Accessors for vframe array top
   // The linked list of vframe arrays are sorted on sp. This means when we
   // unpack the head must contain the vframe array to unpack.
   void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
   vframeArray* vframe_array_head() const         { return _vframe_array_head;  }
   // Side structure for defering update of java frame locals until deopt occurs
   GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
   void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
   // These only really exist to make debugging deopt problems simpler
   void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
   vframeArray* vframe_array_last() const         { return _vframe_array_last;  }
   // The special resourceMark used during deoptimization
   void set_deopt_mark(DeoptResourceMark* value)  { _deopt_mark = value; }
   DeoptResourceMark* deopt_mark(void)            { return _deopt_mark; }
   intptr_t* must_deopt_id()                      { return _must_deopt_id; }
   void     set_must_deopt_id(intptr_t* id)       { _must_deopt_id = id; }
   void     clear_must_deopt_id()                 { _must_deopt_id = NULL; }
   void set_deopt_nmethod(nmethod* nm)            { _deopt_nmethod = nm;   }
   nmethod* deopt_nmethod()                       { return _deopt_nmethod; }
   methodOop  callee_target() const               { return _callee_target; }
   void set_callee_target  (methodOop x)          { _callee_target   = x; }
   // Oop results of vm runtime calls
   oop  vm_result() const                         { return _vm_result; }
   void set_vm_result  (oop x)                    { _vm_result   = x; }
   oop  vm_result_2() const                       { return _vm_result_2; }
   void set_vm_result_2  (oop x)                  { _vm_result_2   = x; }
   MemRegion deferred_card_mark() const           { return _deferred_card_mark; }
   void set_deferred_card_mark(MemRegion mr)      { _deferred_card_mark = mr;   }
   // Exception handling for compiled methods
   oop      exception_oop() const                 { return _exception_oop; }
   int      exception_stack_size() const          { return _exception_stack_size; }
   address  exception_pc() const                  { return _exception_pc; }
   address  exception_handler_pc() const          { return _exception_handler_pc; }
   bool     is_method_handle_return() const       { return _is_method_handle_return == 1; }
   void set_exception_oop(oop o)                  { _exception_oop = o; }
   void set_exception_pc(address a)               { _exception_pc = a; }
   void set_exception_handler_pc(address a)       { _exception_handler_pc = a; }
   void set_exception_stack_size(int size)        { _exception_stack_size = size; }
   void set_is_method_handle_return(bool value)   { _is_method_handle_return = value ? 1 : 0; }
   // Stack overflow support
   inline size_t stack_available(address cur_sp);
   address stack_yellow_zone_base()
     { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
   size_t  stack_yellow_zone_size()
     { return StackYellowPages * os::vm_page_size(); }
   address stack_red_zone_base()
     { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
   size_t stack_red_zone_size()
     { return StackRedPages * os::vm_page_size(); }
   bool in_stack_yellow_zone(address a)
     { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
   bool in_stack_red_zone(address a)
     { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
   void create_stack_guard_pages();
   void remove_stack_guard_pages();
   void enable_stack_yellow_zone();
   void disable_stack_yellow_zone();
   void enable_stack_red_zone();
   void disable_stack_red_zone();
   inline bool stack_yellow_zone_disabled();
   inline bool stack_yellow_zone_enabled();
   // Attempt to reguard the stack after a stack overflow may have occurred.
   // Returns true if (a) guard pages are not needed on this thread, (b) the
   // pages are already guarded, or (c) the pages were successfully reguarded.
   // Returns false if there is not enough stack space to reguard the pages, in
   // which case the caller should unwind a frame and try again.  The argument
   // should be the caller's (approximate) sp.
   bool reguard_stack(address cur_sp);
   // Similar to above but see if current stackpoint is out of the guard area
   // and reguard if possible.
   bool reguard_stack(void);
   // Misc. accessors/mutators
   void set_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = true; }
   void clr_do_not_unlock(void)                   { _do_not_unlock_if_synchronized = false; }
   bool do_not_unlock(void)                       { return _do_not_unlock_if_synchronized; }
 #ifndef PRODUCT
   void record_jump(address target, address instr, const char* file, int line);
 #endif /* PRODUCT */
   // For assembly stub generation
   static ByteSize threadObj_offset()             { return byte_offset_of(JavaThread, _threadObj           ); }
 #ifndef PRODUCT
   static ByteSize jmp_ring_index_offset()        { return byte_offset_of(JavaThread, _jmp_ring_index      ); }
   static ByteSize jmp_ring_offset()              { return byte_offset_of(JavaThread, _jmp_ring            ); }
 #endif /* PRODUCT */
   static ByteSize jni_environment_offset()       { return byte_offset_of(JavaThread, _jni_environment     ); }
   static ByteSize last_Java_sp_offset()          {
     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
   }
   static ByteSize last_Java_pc_offset()          {
     return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
   }
   static ByteSize frame_anchor_offset()          {
     return byte_offset_of(JavaThread, _anchor);
   }
   static ByteSize callee_target_offset()         { return byte_offset_of(JavaThread, _callee_target       ); }
   static ByteSize vm_result_offset()             { return byte_offset_of(JavaThread, _vm_result           ); }
   static ByteSize vm_result_2_offset()           { return byte_offset_of(JavaThread, _vm_result_2         ); }
   static ByteSize thread_state_offset()          { return byte_offset_of(JavaThread, _thread_state        ); }
   static ByteSize saved_exception_pc_offset()    { return byte_offset_of(JavaThread, _saved_exception_pc  ); }
   static ByteSize osthread_offset()              { return byte_offset_of(JavaThread, _osthread            ); }
   static ByteSize exception_oop_offset()         { return byte_offset_of(JavaThread, _exception_oop       ); }
   static ByteSize exception_pc_offset()          { return byte_offset_of(JavaThread, _exception_pc        ); }
   static ByteSize exception_handler_pc_offset()  { return byte_offset_of(JavaThread, _exception_handler_pc); }
   static ByteSize exception_stack_size_offset()  { return byte_offset_of(JavaThread, _exception_stack_size); }
   static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
   static ByteSize stack_guard_state_offset()     { return byte_offset_of(JavaThread, _stack_guard_state   ); }
   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
   static ByteSize should_post_on_exceptions_flag_offset() {
     return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
   }
 #ifndef SERIALGC
   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
   static ByteSize dirty_card_queue_offset()      { return byte_offset_of(JavaThread, _dirty_card_queue); }
 #endif // !SERIALGC
   // Returns the jni environment for this thread
   JNIEnv* jni_environment()                      { return &_jni_environment; }
   static JavaThread* thread_from_jni_environment(JNIEnv* env) {
     JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
     // Only return NULL if thread is off the thread list; starting to
     // exit should not return NULL.
     if (thread_from_jni_env->is_terminated()) {
        thread_from_jni_env->block_if_vm_exited();
        return NULL;
     } else {
        return thread_from_jni_env;
     }
   }
   // JNI critical regions. These can nest.
   bool in_critical()    { return _jni_active_critical > 0; }
   void enter_critical() { assert(Thread::current() == this,
                                  "this must be current thread");
                           _jni_active_critical++; }
   void exit_critical()  { assert(Thread::current() == this,
                                  "this must be current thread");
                           _jni_active_critical--;
                           assert(_jni_active_critical >= 0,
                                  "JNI critical nesting problem?"); }
   // For deadlock detection
   int depth_first_number() { return _depth_first_number; }
   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
  private:
   void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
  public:
   MonitorChunk* monitor_chunks() const           { return _monitor_chunks; }
   void add_monitor_chunk(MonitorChunk* chunk);
   void remove_monitor_chunk(MonitorChunk* chunk);
   bool in_deopt_handler() const                  { return _in_deopt_handler > 0; }
   void inc_in_deopt_handler()                    { _in_deopt_handler++; }
   void dec_in_deopt_handler()                    {
     assert(_in_deopt_handler > 0, "mismatched deopt nesting");
     if (_in_deopt_handler > 0) { // robustness
       _in_deopt_handler--;
     }
   }
  private:
   void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
  public:
   // Frame iteration; calls the function f for all frames on the stack
   void frames_do(void f(frame*, const RegisterMap*));
   // Memory operations
   void oops_do(OopClosure* f, CodeBlobClosure* cf);
   // Sweeper operations
   void nmethods_do(CodeBlobClosure* cf);
   // Memory management operations
   void gc_epilogue();
   void gc_prologue();
   // Misc. operations
   char* name() const { return (char*)get_thread_name(); }
   void print_on(outputStream* st) const;
   void print() const { print_on(tty); }
   void print_value();
   void print_thread_state_on(outputStream* ) const      PRODUCT_RETURN;
   void print_thread_state() const                       PRODUCT_RETURN;
   void print_on_error(outputStream* st, char* buf, int buflen) const;
   void verify();
   const char* get_thread_name() const;
 private:
   // factor out low-level mechanics for use in both normal and error cases
   const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
 public:
   const char* get_threadgroup_name() const;
   const char* get_parent_name() const;
   // Accessing frames
   frame last_frame() {
     _anchor.make_walkable(this);
     return pd_last_frame();
   }
   javaVFrame* last_java_vframe(RegisterMap* reg_map);
   // Returns method at 'depth' java or native frames down the stack
   // Used for security checks
   klassOop security_get_caller_class(int depth);
   // Print stack trace in external format
   void print_stack_on(outputStream* st);
   void print_stack() { print_stack_on(tty); }
   // Print stack traces in various internal formats
   void trace_stack()                             PRODUCT_RETURN;
   void trace_stack_from(vframe* start_vf)        PRODUCT_RETURN;
   void trace_frames()                            PRODUCT_RETURN;
   // Returns the number of stack frames on the stack
   int depth() const;
   // Function for testing deoptimization
   void deoptimize();
   void make_zombies();
   void deoptimized_wrt_marked_nmethods();
   // Profiling operation (see fprofile.cpp)
  public:
    bool profile_last_Java_frame(frame* fr);
  private:
    ThreadProfiler* _thread_profiler;
  private:
    friend class FlatProfiler;                    // uses both [gs]et_thread_profiler.
    friend class FlatProfilerTask;                // uses get_thread_profiler.
    friend class ThreadProfilerMark;              // uses get_thread_profiler.
    ThreadProfiler* get_thread_profiler()         { return _thread_profiler; }
    ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
      ThreadProfiler* result = _thread_profiler;
      _thread_profiler = tp;
      return result;
    }
   // Static operations
  public:
   // Returns the running thread as a JavaThread
   static inline JavaThread* current();
   // Returns the active Java thread.  Do not use this if you know you are calling
   // from a JavaThread, as it's slower than JavaThread::current.  If called from
   // the VMThread, it also returns the JavaThread that instigated the VMThread's
   // operation.  You may not want that either.
   static JavaThread* active();
   inline CompilerThread* as_CompilerThread();
  public:
   virtual void run();
   void thread_main_inner();
  private:
   // PRIVILEGED STACK
   PrivilegedElement*  _privileged_stack_top;
   GrowableArray<oop>* _array_for_gc;
  public:
   // Returns the privileged_stack information.
   PrivilegedElement* privileged_stack_top() const       { return _privileged_stack_top; }
   void set_privileged_stack_top(PrivilegedElement *e)   { _privileged_stack_top = e; }
   void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
  public:
   // Thread local information maintained by JVMTI.
   void set_jvmti_thread_state(JvmtiThreadState *value)                           { _jvmti_thread_state = value; }
   // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
   // getter is used to get this JavaThread's JvmtiThreadState if it has
   // one which means NULL can be returned. JvmtiThreadState::state_for()
   // is used to get the specified JavaThread's JvmtiThreadState if it has
   // one or it allocates a new JvmtiThreadState for the JavaThread and
   // returns it. JvmtiThreadState::state_for() will return NULL only if
   // the specified JavaThread is exiting.
   JvmtiThreadState *jvmti_thread_state() const                                   { return _jvmti_thread_state; }
   static ByteSize jvmti_thread_state_offset()                                    { return byte_offset_of(JavaThread, _jvmti_thread_state); }
   void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
   JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const     { return _jvmti_get_loaded_classes_closure; }
   // JVMTI PopFrame support
   // Setting and clearing popframe_condition
   // All of these enumerated values are bits. popframe_pending
   // indicates that a PopFrame() has been requested and not yet been
   // completed. popframe_processing indicates that that PopFrame() is in
   // the process of being completed. popframe_force_deopt_reexecution_bit
   // indicates that special handling is required when returning to a
   // deoptimized caller.
   enum PopCondition {
     popframe_inactive                      = 0x00,
     popframe_pending_bit                   = 0x01,
     popframe_processing_bit                = 0x02,
     popframe_force_deopt_reexecution_bit   = 0x04
   };
   PopCondition popframe_condition()                   { return (PopCondition) _popframe_condition; }
   void set_popframe_condition(PopCondition c)         { _popframe_condition = c; }
   void set_popframe_condition_bit(PopCondition c)     { _popframe_condition |= c; }
   void clear_popframe_condition()                     { _popframe_condition = popframe_inactive; }
   static ByteSize popframe_condition_offset()         { return byte_offset_of(JavaThread, _popframe_condition); }
   bool has_pending_popframe()                         { return (popframe_condition() & popframe_pending_bit) != 0; }
   bool popframe_forcing_deopt_reexecution()           { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
   void clear_popframe_forcing_deopt_reexecution()     { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
 #ifdef CC_INTERP
   bool pop_frame_pending(void)                        { return ((_popframe_condition & popframe_pending_bit) != 0); }
   void clr_pop_frame_pending(void)                    { _popframe_condition = popframe_inactive; }
   bool pop_frame_in_process(void)                     { return ((_popframe_condition & popframe_processing_bit) != 0); }
   void set_pop_frame_in_process(void)                 { _popframe_condition |= popframe_processing_bit; }
   void clr_pop_frame_in_process(void)                 { _popframe_condition &= ~popframe_processing_bit; }
 #endif
  private:
   // Saved incoming arguments to popped frame.
   // Used only when popped interpreted frame returns to deoptimized frame.
   void*    _popframe_preserved_args;
   int      _popframe_preserved_args_size;
  public:
   void  popframe_preserve_args(ByteSize size_in_bytes, void* start);
   void* popframe_preserved_args();
   ByteSize popframe_preserved_args_size();
   WordSize popframe_preserved_args_size_in_words();
   void  popframe_free_preserved_args();
  private:
   JvmtiThreadState *_jvmti_thread_state;
   JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
   // Used by the interpreter in fullspeed mode for frame pop, method
   // entry, method exit and single stepping support. This field is
   // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
   // It can be set to zero asynchronously (i.e., without a VM operation
   // or a lock) so we have to be very careful.
   int               _interp_only_mode;
  public:
   // used by the interpreter for fullspeed debugging support (see above)
   static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
   bool is_interp_only_mode()                { return (_interp_only_mode != 0); }
   int get_interp_only_mode()                { return _interp_only_mode; }
   void increment_interp_only_mode()         { ++_interp_only_mode; }
   void decrement_interp_only_mode()         { --_interp_only_mode; }
   // support for cached flag that indicates whether exceptions need to be posted for this thread
   // if this is false, we can avoid deoptimizing when events are thrown
   // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
  private:
   int    _should_post_on_exceptions_flag;
  public:
   int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
   void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
  private:
   ThreadStatistics *_thread_stat;
  public:
   ThreadStatistics* get_thread_stat() const    { return _thread_stat; }
   // Return a blocker object for which this thread is blocked parking.
   oop current_park_blocker();
  private:
   static size_t _stack_size_at_create;
  public:
   static inline size_t stack_size_at_create(void) {
     return _stack_size_at_create;
   }
   static inline void set_stack_size_at_create(size_t value) {
     _stack_size_at_create = value;
   }
 #ifndef SERIALGC
   // SATB marking queue support
   ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
   static SATBMarkQueueSet& satb_mark_queue_set() {
     return _satb_mark_queue_set;
   }
   // Dirty card queue support
   DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
   static DirtyCardQueueSet& dirty_card_queue_set() {
     return _dirty_card_queue_set;
   }
 #endif // !SERIALGC
   // This method initializes the SATB and dirty card queues before a
   // JavaThread is added to the Java thread list. Right now, we don't
   // have to do anything to the dirty card queue (it should have been
   // activated when the thread was created), but we have to activate
   // the SATB queue if the thread is created while a marking cycle is
   // in progress. The activation / de-activation of the SATB queues at
   // the beginning / end of a marking cycle is done during safepoints
   // so we have to make sure this method is called outside one to be
   // able to safely read the active field of the SATB queue set. Right
   // now, it is called just before the thread is added to the Java
   // thread list in the Threads::add() method. That method is holding
   // the Threads_lock which ensures we are outside a safepoint. We
   // cannot do the obvious and set the active field of the SATB queue
   // when the thread is created given that, in some cases, safepoints
   // might happen between the JavaThread constructor being called and the
   // thread being added to the Java thread list (an example of this is
   // when the structure for the DestroyJavaVM thread is created).
 #ifndef SERIALGC
   void initialize_queues();
 #else // !SERIALGC
   void initialize_queues() { }
 #endif // !SERIALGC
   // Machine dependent stuff
 #ifdef TARGET_OS_ARCH_linux_x86
 # include "thread_linux_x86.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_linux_sparc
 # include "thread_linux_sparc.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_linux_zero
 # include "thread_linux_zero.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_solaris_x86
 # include "thread_solaris_x86.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_solaris_sparc
 # include "thread_solaris_sparc.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_windows_x86
 # include "thread_windows_x86.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_linux_arm
 # include "thread_linux_arm.hpp"
 #endif
 #ifdef TARGET_OS_ARCH_linux_ppc
 # include "thread_linux_ppc.hpp"
 #endif
  public:
   void set_blocked_on_compilation(bool value) {
     _blocked_on_compilation = value;
   }
   bool blocked_on_compilation() {
     return _blocked_on_compilation;
   }
  protected:
   bool         _blocked_on_compilation;
   // JSR166 per-thread parker
 private:
   Parker*    _parker;
 public:
   Parker*     parker() { return _parker; }
   // Biased locking support
 private:
   GrowableArray<MonitorInfo*>* _cached_monitor_info;
 public:
   GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
   void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
   // clearing/querying jni attach status
   bool is_attaching() const { return _is_attaching; }
   void set_attached() { _is_attaching = false; OrderAccess::fence(); }
 private:
   // This field is used to determine if a thread has claimed
   // a par_id: it is -1 if the thread has not claimed a par_id;
   // otherwise its value is the par_id that has been claimed.
   int _claimed_par_id;
 public:
   int get_claimed_par_id() { return _claimed_par_id; }
   void set_claimed_par_id(int id) { _claimed_par_id = id;}
 };
 // Inline implementation of JavaThread::current
 inline JavaThread* JavaThread::current() {
   Thread* thread = ThreadLocalStorage::thread();
   assert(thread != NULL && thread->is_Java_thread(), "just checking");
   return (JavaThread*)thread;
 }
 inline CompilerThread* JavaThread::as_CompilerThread() {
   assert(is_Compiler_thread(), "just checking");
   return (CompilerThread*)this;
 }
 inline bool JavaThread::stack_yellow_zone_disabled() {
   return _stack_guard_state == stack_guard_yellow_disabled;
 }
 inline bool JavaThread::stack_yellow_zone_enabled() {
 #ifdef ASSERT
   if (os::uses_stack_guard_pages()) {
     assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
   }
 #endif
     return _stack_guard_state == stack_guard_enabled;
 }
 inline size_t JavaThread::stack_available(address cur_sp) {
   // This code assumes java stacks grow down
   address low_addr; // Limit on the address for deepest stack depth
   if ( _stack_guard_state == stack_guard_unused) {
     low_addr =  stack_base() - stack_size();
   } else {
     low_addr = stack_yellow_zone_base();
   }
   return cur_sp > low_addr ? cur_sp - low_addr : 0;
 }
 // A thread used for Compilation.
 class CompilerThread : public JavaThread {
   friend class VMStructs;
  private:
   CompilerCounters* _counters;
   ciEnv*        _env;
   CompileLog*   _log;
   CompileTask*  _task;
   CompileQueue* _queue;
   BufferBlob*   _buffer_blob;
  public:
   static CompilerThread* current();
   CompilerThread(CompileQueue* queue, CompilerCounters* counters);
   bool is_Compiler_thread() const                { return true; }
   // Hide this compiler thread from external view.
   bool is_hidden_from_external_view() const      { return true; }
   CompileQueue* queue()                          { return _queue; }
   CompilerCounters* counters()                   { return _counters; }
   // Get/set the thread's compilation environment.
   ciEnv*        env()                            { return _env; }
   void          set_env(ciEnv* env)              { _env = env; }
   BufferBlob*   get_buffer_blob()                { return _buffer_blob; }
   void          set_buffer_blob(BufferBlob* b)   { _buffer_blob = b; };
   // Get/set the thread's logging information
   CompileLog*   log()                            { return _log; }
   void          init_log(CompileLog* log) {
     // Set once, for good.
     assert(_log == NULL, "set only once");
     _log = log;
   }
 #ifndef PRODUCT
 private:
   IdealGraphPrinter *_ideal_graph_printer;
 public:
   IdealGraphPrinter *ideal_graph_printer()                       { return _ideal_graph_printer; }
   void set_ideal_graph_printer(IdealGraphPrinter *n)             { _ideal_graph_printer = n; }
 #endif
   // Get/set the thread's current task
   CompileTask*  task()                           { return _task; }
   void          set_task(CompileTask* task)      { _task = task; }
 };
 inline CompilerThread* CompilerThread::current() {
   return JavaThread::current()->as_CompilerThread();
 }
 // The active thread queue. It also keeps track of the current used
 // thread priorities.
 class Threads: AllStatic {
   friend class VMStructs;
  private:
   static JavaThread* _thread_list;
   static int         _number_of_threads;
   static int         _number_of_non_daemon_threads;
   static int         _return_code;
  public:
   // Thread management
   // force_daemon is a concession to JNI, where we may need to add a
   // thread to the thread list before allocating its thread object
   static void add(JavaThread* p, bool force_daemon = false);
   static void remove(JavaThread* p);
   static bool includes(JavaThread* p);
   static JavaThread* first()                     { return _thread_list; }
   static void threads_do(ThreadClosure* tc);
   // Initializes the vm and creates the vm thread
   static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
   static void convert_vm_init_libraries_to_agents();
   static void create_vm_init_libraries();
   static void create_vm_init_agents();
   static void shutdown_vm_agents();
   static bool destroy_vm();
   // Supported VM versions via JNI
   // Includes JNI_VERSION_1_1
   static jboolean is_supported_jni_version_including_1_1(jint version);
   // Does not include JNI_VERSION_1_1
   static jboolean is_supported_jni_version(jint version);
   // Garbage collection
   static void follow_other_roots(void f(oop*));
   // Apply "f->do_oop" to all root oops in all threads.
   // This version may only be called by sequential code.
   static void oops_do(OopClosure* f, CodeBlobClosure* cf);
   // This version may be called by sequential or parallel code.
   static void possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf);
   // This creates a list of GCTasks, one per thread.
   static void create_thread_roots_tasks(GCTaskQueue* q);
   // This creates a list of GCTasks, one per thread, for marking objects.
   static void create_thread_roots_marking_tasks(GCTaskQueue* q);
   // Apply "f->do_oop" to roots in all threads that
   // are part of compiled frames
   static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf);
   static void convert_hcode_pointers();
   static void restore_hcode_pointers();
   // Sweeper
   static void nmethods_do(CodeBlobClosure* cf);
   static void gc_epilogue();
   static void gc_prologue();
   // Verification
   static void verify();
   static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
   static void print(bool print_stacks, bool internal_format) {
     // this function is only used by debug.cpp
     print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
   }
   static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
   // Get Java threads that are waiting to enter a monitor. If doLock
   // is true, then Threads_lock is grabbed as needed. Otherwise, the
   // VM needs to be at a safepoint.
   static GrowableArray<JavaThread*>* get_pending_threads(int count,
     address monitor, bool doLock);
   // Get owning Java thread from the monitor's owner field. If doLock
   // is true, then Threads_lock is grabbed as needed. Otherwise, the
   // VM needs to be at a safepoint.
   static JavaThread *owning_thread_from_monitor_owner(address owner,
     bool doLock);
   // Number of threads on the active threads list
   static int number_of_threads()                 { return _number_of_threads; }
   // Number of non-daemon threads on the active threads list
   static int number_of_non_daemon_threads()      { return _number_of_non_daemon_threads; }
   // Deoptimizes all frames tied to marked nmethods
   static void deoptimized_wrt_marked_nmethods();
 };
 // Thread iterator
 class ThreadClosure: public StackObj {
  public:
   virtual void do_thread(Thread* thread) = 0;
 };
 class SignalHandlerMark: public StackObj {
 private:
   Thread* _thread;
 public:
   SignalHandlerMark(Thread* t) {
     _thread = t;
     if (_thread) _thread->enter_signal_handler();
   }
   ~SignalHandlerMark() {
     if (_thread) _thread->leave_signal_handler();
     _thread = NULL;
   }
 };
 #endif // SHARE_VM_RUNTIME_THREAD_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/runtime/thread.hpp@f36c9fe788b8 (annotated)

src/share/vm/runtime/thread.hpp