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 /*

  * Copyright 2003-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 #ifndef _JAVA_JVMTITHREADSTATE_H_

 #define _JAVA_JVMTITHREADSTATE_H_

 //

 // Forward Declarations

 //

 class JvmtiEnvBase;

 class JvmtiEnvThreadState;

 class JvmtiDynamicCodeEventCollector;

 enum JvmtiClassLoadKind {

   jvmti_class_load_kind_load = 100,

   jvmti_class_load_kind_retransform,

   jvmti_class_load_kind_redefine

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiEnvThreadStateIterator

 //

 // The only safe means of iterating through the JvmtiEnvThreadStates

 // in a JvmtiThreadState.

 // Note that this iteratation includes invalid environments pending

 // deallocation -- in fact, some uses depend on this behavior.

 //

 class JvmtiEnvThreadStateIterator : public StackObj {

  private:

   JvmtiThreadState* state;

  public:

   JvmtiEnvThreadStateIterator(JvmtiThreadState* thread_state);

   ~JvmtiEnvThreadStateIterator();

   JvmtiEnvThreadState* first();

   JvmtiEnvThreadState* next(JvmtiEnvThreadState* ets);

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiThreadState

 //

 // The Jvmti state for each thread (across all JvmtiEnv):

 // 1. Local table of enabled events.

 class JvmtiThreadState : public CHeapObj {

  private:

   friend class JvmtiEnv;

   JavaThread        *_thread;

   bool              _exception_detected;

   bool              _exception_caught;

   bool              _hide_single_stepping;

   bool              _pending_step_for_popframe;

   bool              _pending_step_for_earlyret;

   int               _hide_level;

   // Used to send class being redefined/retransformed and kind of transform

   // info to the class file load hook event handler.

   KlassHandle           *_class_being_redefined;

   JvmtiClassLoadKind    _class_load_kind;

   // This is only valid when is_interp_only_mode() returns true

   int               _cur_stack_depth;

   JvmtiThreadEventEnable _thread_event_enable;

   // for support of JvmtiEnvThreadState

   JvmtiEnvThreadState*   _head_env_thread_state;

   // doubly-linked linear list of active thread state

   // needed in order to iterate the list without holding Threads_lock

   static JvmtiThreadState *_head;

   JvmtiThreadState *_next;

   JvmtiThreadState *_prev;

   // holds the current dynamic code event collector, NULL if no event collector in use

   JvmtiDynamicCodeEventCollector* _dynamic_code_event_collector;

   // holds the current vm object alloc event collector, NULL if no event collector in use

   JvmtiVMObjectAllocEventCollector* _vm_object_alloc_event_collector;

   // Should only be created by factory methods

   JvmtiThreadState(JavaThread *thread);

   friend class JvmtiEnvThreadStateIterator;

   inline JvmtiEnvThreadState* head_env_thread_state();

   inline void set_head_env_thread_state(JvmtiEnvThreadState* ets);

  public:

   ~JvmtiThreadState();

   // is event_type enabled and usable for this thread in any enviroments?

   bool is_enabled(jvmtiEvent event_type) {

     return _thread_event_enable.is_enabled(event_type);

   }

   JvmtiThreadEventEnable *thread_event_enable() {

     return &_thread_event_enable;

   }

   // Must only be called in situations where the state is for the current thread and

   // the environment can not go away.  To be safe, the returned JvmtiEnvThreadState

   // must be used in such a way as there can be no intervening safepoints.

   inline JvmtiEnvThreadState* env_thread_state(JvmtiEnvBase *env);

   static void periodic_clean_up();

   void add_env(JvmtiEnvBase *env);

   // Used by the interpreter for fullspeed debugging support

   bool is_interp_only_mode()                { return _thread->is_interp_only_mode(); }

   void enter_interp_only_mode();

   void leave_interp_only_mode();

   // access to the linked list of all JVMTI thread states

   static JvmtiThreadState *first() {

     assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");

     return _head;

   }

   JvmtiThreadState *next()                  {

     return _next;

   }

   // Current stack depth is only valid when is_interp_only_mode() returns true.

   // These functions should only be called at a safepoint - usually called from same thread.

   // Returns the number of Java activations on the stack.

   int cur_stack_depth();

   void invalidate_cur_stack_depth();

   void incr_cur_stack_depth();

   void decr_cur_stack_depth();

   int count_frames();

   inline JavaThread *get_thread()      { return _thread;              }

   inline bool is_exception_detected()  { return _exception_detected;  }

   inline bool is_exception_caught()    { return _exception_caught;  }

   inline void set_exception_detected() { _exception_detected = true;

                                          _exception_caught = false; }

   inline void set_exception_caught()   { _exception_caught = true;

                                          _exception_detected = false; }

   inline void clear_hide_single_stepping() {

     if (_hide_level > 0) {

       _hide_level--;

     } else {

       assert(_hide_single_stepping, "hide_single_stepping is out of phase");

       _hide_single_stepping = false;

     }

   }

   inline bool hide_single_stepping() { return _hide_single_stepping; }

   inline void set_hide_single_stepping() {

     if (_hide_single_stepping) {

       _hide_level++;

     } else {

       assert(_hide_level == 0, "hide_level is out of phase");

       _hide_single_stepping = true;

     }

   }

   // Step pending flag is set when PopFrame is called and it is cleared

   // when step for the Pop Frame is completed.

   // This logic is used to distinguish b/w step for pop frame and repeat step.

   void set_pending_step_for_popframe() { _pending_step_for_popframe = true;  }

   void clr_pending_step_for_popframe() { _pending_step_for_popframe = false; }

   bool is_pending_step_for_popframe()  { return _pending_step_for_popframe;  }

   void process_pending_step_for_popframe();

   // Step pending flag is set when ForceEarlyReturn is called and it is cleared

   // when step for the ForceEarlyReturn is completed.

   // This logic is used to distinguish b/w step for early return and repeat step.

   void set_pending_step_for_earlyret() { _pending_step_for_earlyret = true;  }

   void clr_pending_step_for_earlyret() { _pending_step_for_earlyret = false; }

   bool is_pending_step_for_earlyret()  { return _pending_step_for_earlyret;  }

   void process_pending_step_for_earlyret();

   // Setter and getter method is used to send redefined class info

   // when class file load hook event is posted.

   // It is set while loading redefined class and cleared before the

   // class file load hook event is posted.

   inline void set_class_being_redefined(KlassHandle *h_class, JvmtiClassLoadKind kind) {

     _class_being_redefined = h_class;

     _class_load_kind = kind;

   }

   inline void clear_class_being_redefined() {

     _class_being_redefined = NULL;

     _class_load_kind = jvmti_class_load_kind_load;

   }

   inline KlassHandle *get_class_being_redefined() {

     return _class_being_redefined;

   }

   inline JvmtiClassLoadKind get_class_load_kind() {

     return _class_load_kind;

   }

   // RedefineClasses support

   // The bug 6214132 caused the verification to fail.

   //

   // Below is the detailed description of the fix approach taken:

   // 1. What's done in RedefineClasses() before verification:

   //  a) A reference to the class being redefined (_the_class) and a

   //     reference to new version of the class (_scratch_class) are

   //     saved here for use during the bytecode verification phase of

   //     RedefineClasses. See RedefineVerifyMark for how these fields

   //     are managed.

   //   b) The _java_mirror field from _the_class is copied to the

   //     _java_mirror field in _scratch_class. This means that a jclass

   //     returned for _the_class or _scratch_class will refer to the

   //     same Java mirror. The verifier will see the "one true mirror"

   //     for the class being verified.

   // 2. What is done at verification:

   //   When the verifier makes calls into the VM to ask questions about

   //   the class being verified, it will pass the jclass to JVM_* functions.

   //   The jclass is always pointing to the mirror of _the_class.

   //   ~28 JVM_* functions called by the verifier for the information

   //   about CP entries and klass structure should check the jvmtiThreadState

   //   info about equivalent klass versions and use it to replace a klassOop

   //   of _the_class with a klassOop of _scratch_class. The function

   //   class_to_verify_considering_redefinition() must be called for it.

   //

   //   Note again, that this redirection happens only for the verifier thread.

   //   Other threads have very small overhead by checking the existence

   //   of the jvmtiThreadSate and the information about klasses equivalence.

   //   No JNI functions need to be changed, they don't reference the klass guts.

   //   The JavaThread pointer is already available in all JVM_* functions

   //   used by the verifier, so there is no extra performance issue with it.

  private:

   KlassHandle *_the_class_for_redefinition_verification;

   KlassHandle *_scratch_class_for_redefinition_verification;

  public:

   inline void set_class_versions_map(KlassHandle *the_class,

                                      KlassHandle *scratch_class) {

     _the_class_for_redefinition_verification = the_class;

     _scratch_class_for_redefinition_verification = scratch_class;

   }

   inline void clear_class_versions_map() { set_class_versions_map(NULL, NULL); }

   static inline

   klassOop class_to_verify_considering_redefinition(klassOop klass,

                                                     JavaThread *thread) {

     JvmtiThreadState *state = thread->jvmti_thread_state();

     if (state != NULL && state->_the_class_for_redefinition_verification != NULL) {

       if ((*(state->_the_class_for_redefinition_verification))() == klass) {

         klass = (*(state->_scratch_class_for_redefinition_verification))();

       }

     }

     return klass;

   }

   // Todo: get rid of this!

  private:

   bool _debuggable;

  public:

   // Should the thread be enumerated by jvmtiInternal::GetAllThreads?

   bool is_debuggable()                 { return _debuggable; }

   // If a thread cannot be suspended (has no valid last_java_frame) then it gets marked !debuggable

   void set_debuggable(bool debuggable) { _debuggable = debuggable; }

  public:

   bool may_be_walked();

   // Thread local event collector setter and getter methods.

   JvmtiDynamicCodeEventCollector* get_dynamic_code_event_collector() {

     return _dynamic_code_event_collector;

   }

   JvmtiVMObjectAllocEventCollector* get_vm_object_alloc_event_collector() {

     return _vm_object_alloc_event_collector;

   }

   void set_dynamic_code_event_collector(JvmtiDynamicCodeEventCollector* collector) {

     _dynamic_code_event_collector = collector;

   }

   void set_vm_object_alloc_event_collector(JvmtiVMObjectAllocEventCollector* collector) {

     _vm_object_alloc_event_collector = collector;

   }

   //

   // Frame routines

   //

  public:

   //  true when the thread was suspended with a pointer to the last Java frame.

   bool has_last_frame()                     { return _thread->has_last_Java_frame(); }

   void update_for_pop_top_frame();

   // already holding JvmtiThreadState_lock - retrieve or create JvmtiThreadState

   inline static JvmtiThreadState *state_for_while_locked(JavaThread *thread) {

     assert(JvmtiThreadState_lock->is_locked(), "sanity check");

     JvmtiThreadState *state = thread->jvmti_thread_state();

     if (state == NULL) {

       state = new JvmtiThreadState(thread);

     }

     return state;

   }

   // retrieve or create JvmtiThreadState

   inline static JvmtiThreadState *state_for(JavaThread *thread) {

     JvmtiThreadState *state = thread->jvmti_thread_state();

     if (state == NULL) {

       MutexLocker mu(JvmtiThreadState_lock);

       // check again with the lock held

       state = state_for_while_locked(thread);

     } else {

       CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

     }

     return state;

   }

   // JVMTI ForceEarlyReturn support

   // This is set to earlyret_pending to signal that top Java frame

   // should be returned immediately

  public:

   int           _earlyret_state;

   TosState      _earlyret_tos;

   jvalue        _earlyret_value;

   oop           _earlyret_oop;         // Used to return an oop result into Java code from

                                        // ForceEarlyReturnObject, GC-preserved

   // Setting and clearing earlyret_state

   // earlyret_pending indicates that a ForceEarlyReturn() has been

   // requested and not yet been completed.

  public:

   enum EarlyretState {

     earlyret_inactive = 0,

     earlyret_pending  = 1

   };

   void set_earlyret_pending(void) { _earlyret_state = earlyret_pending;  }

   void clr_earlyret_pending(void) { _earlyret_state = earlyret_inactive; }

   bool is_earlyret_pending(void)  { return (_earlyret_state == earlyret_pending);  }

   TosState earlyret_tos()                            { return _earlyret_tos; }

   oop  earlyret_oop() const                          { return _earlyret_oop; }

   void set_earlyret_oop (oop x)                      { _earlyret_oop = x;    }

   jvalue earlyret_value()                            { return _earlyret_value; }

   void set_earlyret_value(jvalue val, TosState tos)  { _earlyret_tos = tos;  _earlyret_value = val;  }

   void clr_earlyret_value()                          { _earlyret_tos = ilgl; _earlyret_value.j = 0L; }

   static ByteSize earlyret_state_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_state); }

   static ByteSize earlyret_tos_offset()   { return byte_offset_of(JvmtiThreadState, _earlyret_tos); }

   static ByteSize earlyret_oop_offset()   { return byte_offset_of(JvmtiThreadState, _earlyret_oop); }

   static ByteSize earlyret_value_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_value); }

   void oops_do(OopClosure* f); // GC support

 };

 class RedefineVerifyMark : public StackObj {

  private:

   JvmtiThreadState *_state;

  public:

   RedefineVerifyMark(KlassHandle *the_class, KlassHandle *scratch_class,

                      JvmtiThreadState *state) : _state(state)

   {

     _state->set_class_versions_map(the_class, scratch_class);

     (*scratch_class)->set_java_mirror((*the_class)->java_mirror());

   }

   ~RedefineVerifyMark() {

     _state->clear_class_versions_map();

   }

 };

 #endif   /* _JAVA_JVMTITHREADSTATE_H_ */