/* * metadata/gc.c: GC icalls. * * Author: Paolo Molaro * * Copyright 2002-2003 Ximian, Inc (http://www.ximian.com) * Copyright 2004-2009 Novell, Inc (http://www.novell.com) * Copyright 2012 Xamarin Inc (http://www.xamarin.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for mono_delegate_free_ftnptr () */ #include #include #include #include #include #include #include #include #include #include #ifndef HOST_WIN32 #include #endif typedef struct DomainFinalizationReq { MonoDomain *domain; HANDLE done_event; } DomainFinalizationReq; static gboolean gc_disabled = FALSE; static gboolean finalizing_root_domain = FALSE; gboolean log_finalizers = FALSE; gboolean mono_do_not_finalize = FALSE; gchar **mono_do_not_finalize_class_names = NULL; #define mono_finalizer_lock() mono_coop_mutex_lock (&finalizer_mutex) #define mono_finalizer_unlock() mono_coop_mutex_unlock (&finalizer_mutex) static MonoCoopMutex finalizer_mutex; static MonoCoopMutex reference_queue_mutex; static GSList *domains_to_finalize= NULL; static MonoMList *threads_to_finalize = NULL; static gboolean finalizer_thread_exited; /* Uses finalizer_mutex */ static MonoCoopCond exited_cond; static MonoInternalThread *gc_thread; static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*), MonoError *error); static void reference_queue_proccess_all (void); static void mono_reference_queue_cleanup (void); static void reference_queue_clear_for_domain (MonoDomain *domain); static HANDLE pending_done_event; static guint32 guarded_wait (HANDLE handle, guint32 timeout, gboolean alertable) { guint32 result; MONO_PREPARE_BLOCKING; result = WaitForSingleObjectEx (handle, timeout, alertable); MONO_FINISH_BLOCKING; return result; } static void add_thread_to_finalize (MonoInternalThread *thread) { mono_finalizer_lock (); if (!threads_to_finalize) MONO_GC_REGISTER_ROOT_SINGLE (threads_to_finalize, MONO_ROOT_SOURCE_FINALIZER_QUEUE, "finalizable threads list"); threads_to_finalize = mono_mlist_append (threads_to_finalize, (MonoObject*)thread); mono_finalizer_unlock (); } static gboolean suspend_finalizers = FALSE; /* * actually, we might want to queue the finalize requests in a separate thread, * but we need to be careful about the execution domain of the thread... */ void mono_gc_run_finalize (void *obj, void *data) { MonoError error; MonoObject *exc = NULL; MonoObject *o; #ifndef HAVE_SGEN_GC MonoObject *o2; #endif MonoMethod* finalizer = NULL; MonoDomain *caller_domain = mono_domain_get (); MonoDomain *domain; RuntimeInvokeFunction runtime_invoke; // This function is called from the innards of the GC, so our best alternative for now is to do polling here mono_threads_safepoint (); o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data)); if (mono_do_not_finalize) { if (!mono_do_not_finalize_class_names) return; size_t namespace_len = strlen (o->vtable->klass->name_space); for (int i = 0; mono_do_not_finalize_class_names [i]; ++i) { const char *name = mono_do_not_finalize_class_names [i]; if (strncmp (name, o->vtable->klass->name_space, namespace_len)) break; if (name [namespace_len] != '.') break; if (strcmp (name + namespace_len + 1, o->vtable->klass->name)) break; return; } } if (log_finalizers) g_log ("mono-gc-finalizers", G_LOG_LEVEL_DEBUG, "<%s at %p> Starting finalizer checks.", o->vtable->klass->name, o); if (suspend_finalizers) return; domain = o->vtable->domain; #ifndef HAVE_SGEN_GC mono_domain_finalizers_lock (domain); o2 = (MonoObject *)g_hash_table_lookup (domain->finalizable_objects_hash, o); mono_domain_finalizers_unlock (domain); if (!o2) /* Already finalized somehow */ return; #endif /* make sure the finalizer is not called again if the object is resurrected */ object_register_finalizer ((MonoObject *)obj, NULL, &error); mono_error_assert_ok (&error); /* FIXME don't swallow the error */ if (log_finalizers) g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Registered finalizer as processed.", o->vtable->klass->name, o); if (o->vtable->klass == mono_defaults.internal_thread_class) { MonoInternalThread *t = (MonoInternalThread*)o; if (mono_gc_is_finalizer_internal_thread (t)) /* Avoid finalizing ourselves */ return; if (t->threadpool_thread && finalizing_root_domain) { /* Don't finalize threadpool threads when shutting down - they're finalized when the threadpool shuts down. */ add_thread_to_finalize (t); return; } } if (o->vtable->klass->image == mono_defaults.corlib && !strcmp (o->vtable->klass->name, "DynamicMethod") && finalizing_root_domain) { /* * These can't be finalized during unloading/shutdown, since that would * free the native code which can still be referenced by other * finalizers. * FIXME: This is not perfect, objects dying at the same time as * dynamic methods can still reference them even when !shutdown. */ return; } if (mono_runtime_get_no_exec ()) return; /* speedup later... and use a timeout */ /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */ /* Use _internal here, since this thread can enter a doomed appdomain */ mono_domain_set_internal (mono_object_domain (o)); /* delegates that have a native function pointer allocated are * registered for finalization, but they don't have a Finalize * method, because in most cases it's not needed and it's just a waste. */ if (o->vtable->klass->delegate) { MonoDelegate* del = (MonoDelegate*)o; if (del->delegate_trampoline) mono_delegate_free_ftnptr ((MonoDelegate*)o); mono_domain_set_internal (caller_domain); return; } finalizer = mono_class_get_finalizer (o->vtable->klass); /* If object has a CCW but has no finalizer, it was only * registered for finalization in order to free the CCW. * Else it needs the regular finalizer run. * FIXME: what to do about ressurection and suppression * of finalizer on object with CCW. */ if (mono_marshal_free_ccw (o) && !finalizer) { mono_domain_set_internal (caller_domain); return; } /* * To avoid the locking plus the other overhead of mono_runtime_invoke_checked (), * create and precompile a wrapper which calls the finalize method using * a CALLVIRT. */ if (log_finalizers) g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Compiling finalizer.", o->vtable->klass->name, o); if (!domain->finalize_runtime_invoke) { MonoMethod *invoke = mono_marshal_get_runtime_invoke (mono_class_get_method_from_name_flags (mono_defaults.object_class, "Finalize", 0, 0), TRUE); domain->finalize_runtime_invoke = mono_compile_method (invoke); } runtime_invoke = (RuntimeInvokeFunction)domain->finalize_runtime_invoke; mono_runtime_class_init_full (o->vtable, &error); mono_error_raise_exception (&error); /* FIXME don't raise here */ if (G_UNLIKELY (MONO_GC_FINALIZE_INVOKE_ENABLED ())) { MONO_GC_FINALIZE_INVOKE ((unsigned long)o, mono_object_get_size (o), o->vtable->klass->name_space, o->vtable->klass->name); } if (log_finalizers) g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Calling finalizer.", o->vtable->klass->name, o); runtime_invoke (o, NULL, &exc, NULL); if (log_finalizers) g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Returned from finalizer.", o->vtable->klass->name, o); if (exc) mono_thread_internal_unhandled_exception (exc); mono_domain_set_internal (caller_domain); } void mono_gc_finalize_threadpool_threads (void) { MonoError error; while (threads_to_finalize) { MonoInternalThread *thread = (MonoInternalThread*) mono_mlist_get_data (threads_to_finalize); /* Force finalization of the thread. */ thread->threadpool_thread = FALSE; mono_object_register_finalizer ((MonoObject*)thread, &error); mono_error_assert_ok (&error); /* FIXME don't swallow the error */ mono_gc_run_finalize (thread, NULL); threads_to_finalize = mono_mlist_next (threads_to_finalize); } } gpointer mono_gc_out_of_memory (size_t size) { /* * we could allocate at program startup some memory that we could release * back to the system at this point if we're really low on memory (ie, size is * lower than the memory we set apart) */ mono_raise_exception (mono_domain_get ()->out_of_memory_ex); return NULL; } /* * Some of our objects may point to a different address than the address returned by GC_malloc() * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer. * This also means that in the callback we need to adjust the pointer to get back the real * MonoObject*. * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer, * since that, too, can cause the underlying pointer to be offset. */ static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*), MonoError *error) { MonoDomain *domain; mono_error_init (error); if (obj == NULL) { mono_error_set_argument_null (error, "obj", ""); return; } domain = obj->vtable->domain; #if HAVE_BOEHM_GC if (mono_domain_is_unloading (domain) && (callback != NULL)) /* * Can't register finalizers in a dying appdomain, since they * could be invoked after the appdomain has been unloaded. */ return; mono_domain_finalizers_lock (domain); if (callback) g_hash_table_insert (domain->finalizable_objects_hash, obj, obj); else g_hash_table_remove (domain->finalizable_objects_hash, obj); mono_domain_finalizers_unlock (domain); mono_gc_register_for_finalization (obj, callback); #elif defined(HAVE_SGEN_GC) /* * If we register finalizers for domains that are unloading we might * end up running them while or after the domain is being cleared, so * the objects will not be valid anymore. */ if (!mono_domain_is_unloading (domain)) mono_gc_register_for_finalization (obj, callback); #endif } /** * mono_object_register_finalizer: * @obj: object to register * * Records that object @obj has a finalizer, this will call the * Finalize method when the garbage collector disposes the object. * */ void mono_object_register_finalizer (MonoObject *obj, MonoError *error) { /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */ object_register_finalizer (obj, mono_gc_run_finalize, error); } /** * mono_domain_finalize: * @domain: the domain to finalize * @timeout: msects to wait for the finalization to complete, -1 to wait indefinitely * * Request finalization of all finalizable objects inside @domain. Wait * @timeout msecs for the finalization to complete. * * Returns: TRUE if succeeded, FALSE if there was a timeout */ gboolean mono_domain_finalize (MonoDomain *domain, guint32 timeout) { DomainFinalizationReq *req; guint32 res; HANDLE done_event; MonoInternalThread *thread = mono_thread_internal_current (); #if defined(__native_client__) return FALSE; #endif if (mono_thread_internal_current () == gc_thread) /* We are called from inside a finalizer, not much we can do here */ return FALSE; /* * No need to create another thread 'cause the finalizer thread * is still working and will take care of running the finalizers */ if (gc_disabled) return TRUE; /* We don't support domain finalization without a GC */ if (mono_gc_is_null ()) return FALSE; mono_gc_collect (mono_gc_max_generation ()); done_event = CreateEvent (NULL, TRUE, FALSE, NULL); if (done_event == NULL) { return FALSE; } req = g_new0 (DomainFinalizationReq, 1); req->domain = domain; req->done_event = done_event; if (domain == mono_get_root_domain ()) finalizing_root_domain = TRUE; mono_finalizer_lock (); domains_to_finalize = g_slist_append (domains_to_finalize, req); mono_finalizer_unlock (); /* Tell the finalizer thread to finalize this appdomain */ mono_gc_finalize_notify (); if (timeout == -1) timeout = INFINITE; while (TRUE) { res = guarded_wait (done_event, timeout, TRUE); /* printf ("WAIT RES: %d.\n", res); */ if (res == WAIT_IO_COMPLETION) { if ((thread->state & (ThreadState_StopRequested | ThreadState_SuspendRequested)) != 0) return FALSE; } else if (res == WAIT_TIMEOUT) { /* We leak the handle here */ return FALSE; } else { break; } } CloseHandle (done_event); if (domain == mono_get_root_domain ()) { mono_threadpool_ms_cleanup (); mono_gc_finalize_threadpool_threads (); } return TRUE; } void ves_icall_System_GC_InternalCollect (int generation) { mono_gc_collect (generation); } gint64 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection) { if (forceCollection) mono_gc_collect (mono_gc_max_generation ()); return mono_gc_get_used_size (); } void ves_icall_System_GC_KeepAlive (MonoObject *obj) { /* * Does nothing. */ } void ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj) { MonoError error; MONO_CHECK_ARG_NULL (obj,); object_register_finalizer (obj, mono_gc_run_finalize, &error); mono_error_set_pending_exception (&error); } void ves_icall_System_GC_SuppressFinalize (MonoObject *obj) { MonoError error; MONO_CHECK_ARG_NULL (obj,); /* delegates have no finalizers, but we register them to deal with the * unmanaged->managed trampoline. We don't let the user suppress it * otherwise we'd leak it. */ if (obj->vtable->klass->delegate) return; /* FIXME: Need to handle case where obj has COM Callable Wrapper * generated for it that needs cleaned up, but user wants to suppress * their derived object finalizer. */ object_register_finalizer (obj, NULL, &error); mono_error_set_pending_exception (&error); } void ves_icall_System_GC_WaitForPendingFinalizers (void) { if (mono_gc_is_null ()) return; if (!mono_gc_pending_finalizers ()) return; if (mono_thread_internal_current () == gc_thread) /* Avoid deadlocks */ return; /* If the finalizer thread is not live, lets pretend no finalizers are pending since the current thread might be the one responsible for starting it up. */ if (gc_thread == NULL) return; ResetEvent (pending_done_event); mono_gc_finalize_notify (); /* g_print ("Waiting for pending finalizers....\n"); */ guarded_wait (pending_done_event, INFINITE, TRUE); /* g_print ("Done pending....\n"); */ } void ves_icall_System_GC_register_ephemeron_array (MonoObject *array) { #ifdef HAVE_SGEN_GC if (!mono_gc_ephemeron_array_add (array)) { mono_set_pending_exception (mono_object_domain (array)->out_of_memory_ex); return; } #endif } MonoObject* ves_icall_System_GC_get_ephemeron_tombstone (void) { return mono_domain_get ()->ephemeron_tombstone; } MonoObject * ves_icall_System_GCHandle_GetTarget (guint32 handle) { return mono_gchandle_get_target (handle); } /* * if type == -1, change the target of the handle, otherwise allocate a new handle. */ guint32 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type) { if (type == -1) { mono_gchandle_set_target (handle, obj); /* the handle doesn't change */ return handle; } switch (type) { case HANDLE_WEAK: return mono_gchandle_new_weakref (obj, FALSE); case HANDLE_WEAK_TRACK: return mono_gchandle_new_weakref (obj, TRUE); case HANDLE_NORMAL: return mono_gchandle_new (obj, FALSE); case HANDLE_PINNED: return mono_gchandle_new (obj, TRUE); default: g_assert_not_reached (); } return 0; } void ves_icall_System_GCHandle_FreeHandle (guint32 handle) { mono_gchandle_free (handle); } gpointer ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle) { MonoObject *obj; if (MONO_GC_HANDLE_TYPE (handle) != HANDLE_PINNED) return (gpointer)-2; obj = mono_gchandle_get_target (handle); if (obj) { MonoClass *klass = mono_object_class (obj); if (klass == mono_defaults.string_class) { return mono_string_chars ((MonoString*)obj); } else if (klass->rank) { return mono_array_addr ((MonoArray*)obj, char, 0); } else { /* the C# code will check and throw the exception */ /* FIXME: missing !klass->blittable test, see bug #61134 */ if ((klass->flags & TYPE_ATTRIBUTE_LAYOUT_MASK) == TYPE_ATTRIBUTE_AUTO_LAYOUT) return (gpointer)-1; return (char*)obj + sizeof (MonoObject); } } return NULL; } MonoBoolean mono_gc_GCHandle_CheckCurrentDomain (guint32 gchandle) { return mono_gchandle_is_in_domain (gchandle, mono_domain_get ()); } static MonoCoopSem finalizer_sem; static volatile gboolean finished=FALSE; void mono_gc_finalize_notify (void) { #ifdef DEBUG g_message ( "%s: prodding finalizer", __func__); #endif if (mono_gc_is_null ()) return; mono_coop_sem_post (&finalizer_sem); } #ifdef HAVE_BOEHM_GC static void collect_objects (gpointer key, gpointer value, gpointer user_data) { GPtrArray *arr = (GPtrArray*)user_data; g_ptr_array_add (arr, key); } #endif /* * finalize_domain_objects: * * Run the finalizers of all finalizable objects in req->domain. */ static void finalize_domain_objects (DomainFinalizationReq *req) { MonoDomain *domain = req->domain; #if HAVE_SGEN_GC #define NUM_FOBJECTS 64 MonoObject *to_finalize [NUM_FOBJECTS]; int count; #endif /* Process finalizers which are already in the queue */ mono_gc_invoke_finalizers (); #ifdef HAVE_BOEHM_GC while (g_hash_table_size (domain->finalizable_objects_hash) > 0) { int i; GPtrArray *objs; /* * Since the domain is unloading, nobody is allowed to put * new entries into the hash table. But finalize_object might * remove entries from the hash table, so we make a copy. */ objs = g_ptr_array_new (); g_hash_table_foreach (domain->finalizable_objects_hash, collect_objects, objs); /* printf ("FINALIZING %d OBJECTS.\n", objs->len); */ for (i = 0; i < objs->len; ++i) { MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i); /* FIXME: Avoid finalizing threads, etc */ mono_gc_run_finalize (o, 0); } g_ptr_array_free (objs, TRUE); } #elif defined(HAVE_SGEN_GC) while ((count = mono_gc_finalizers_for_domain (domain, to_finalize, NUM_FOBJECTS))) { int i; for (i = 0; i < count; ++i) { mono_gc_run_finalize (to_finalize [i], 0); } } #endif /* cleanup the reference queue */ reference_queue_clear_for_domain (domain); /* printf ("DONE.\n"); */ SetEvent (req->done_event); /* The event is closed in mono_domain_finalize if we get here */ g_free (req); } static guint32 finalizer_thread (gpointer unused) { gboolean wait = TRUE; while (!finished) { /* Wait to be notified that there's at least one * finaliser to run */ g_assert (mono_domain_get () == mono_get_root_domain ()); mono_gc_set_skip_thread (TRUE); if (wait) { /* An alertable wait is required so this thread can be suspended on windows */ mono_coop_sem_wait (&finalizer_sem, MONO_SEM_FLAGS_ALERTABLE); } wait = TRUE; mono_gc_set_skip_thread (FALSE); mono_threads_perform_thread_dump (); mono_console_handle_async_ops (); mono_attach_maybe_start (); if (domains_to_finalize) { mono_finalizer_lock (); if (domains_to_finalize) { DomainFinalizationReq *req = (DomainFinalizationReq *)domains_to_finalize->data; domains_to_finalize = g_slist_remove (domains_to_finalize, req); mono_finalizer_unlock (); finalize_domain_objects (req); } else { mono_finalizer_unlock (); } } /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup), * before the domain is unloaded. */ mono_gc_invoke_finalizers (); mono_threads_join_threads (); reference_queue_proccess_all (); /* Avoid posting the pending done event until there are pending finalizers */ if (mono_coop_sem_timedwait (&finalizer_sem, 0, MONO_SEM_FLAGS_NONE) == 0) { /* Don't wait again at the start of the loop */ wait = FALSE; } else { SetEvent (pending_done_event); } } mono_finalizer_lock (); finalizer_thread_exited = TRUE; mono_coop_cond_signal (&exited_cond); mono_finalizer_unlock (); return 0; } #ifndef LAZY_GC_THREAD_CREATION static #endif void mono_gc_init_finalizer_thread (void) { gc_thread = mono_thread_create_internal (mono_domain_get (), finalizer_thread, NULL, FALSE, 0); ves_icall_System_Threading_Thread_SetName_internal (gc_thread, mono_string_new (mono_domain_get (), "Finalizer")); } void mono_gc_init (void) { mono_coop_mutex_init_recursive (&finalizer_mutex); mono_coop_mutex_init_recursive (&reference_queue_mutex); mono_counters_register ("Minor GC collections", MONO_COUNTER_GC | MONO_COUNTER_UINT, &gc_stats.minor_gc_count); mono_counters_register ("Major GC collections", MONO_COUNTER_GC | MONO_COUNTER_UINT, &gc_stats.major_gc_count); mono_counters_register ("Minor GC time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.minor_gc_time); mono_counters_register ("Major GC time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.major_gc_time); mono_counters_register ("Major GC time concurrent", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.major_gc_time_concurrent); mono_gc_base_init (); if (mono_gc_is_disabled ()) { gc_disabled = TRUE; return; } pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL); g_assert (pending_done_event); mono_coop_cond_init (&exited_cond); mono_coop_sem_init (&finalizer_sem, 0); #ifndef LAZY_GC_THREAD_CREATION mono_gc_init_finalizer_thread (); #endif } void mono_gc_cleanup (void) { #ifdef DEBUG g_message ("%s: cleaning up finalizer", __func__); #endif if (mono_gc_is_null ()) return; if (!gc_disabled) { finished = TRUE; if (mono_thread_internal_current () != gc_thread) { gboolean timed_out = FALSE; guint32 start_ticks = mono_msec_ticks (); guint32 end_ticks = start_ticks + 2000; mono_gc_finalize_notify (); /* Finishing the finalizer thread, so wait a little bit... */ /* MS seems to wait for about 2 seconds */ while (!finalizer_thread_exited) { guint32 current_ticks = mono_msec_ticks (); guint32 timeout; if (current_ticks >= end_ticks) break; else timeout = end_ticks - current_ticks; mono_finalizer_lock (); if (!finalizer_thread_exited) mono_coop_cond_timedwait (&exited_cond, &finalizer_mutex, timeout); mono_finalizer_unlock (); } if (!finalizer_thread_exited) { int ret; /* Set a flag which the finalizer thread can check */ suspend_finalizers = TRUE; /* Try to abort the thread, in the hope that it is running managed code */ mono_thread_internal_stop (gc_thread); /* Wait for it to stop */ ret = guarded_wait (gc_thread->handle, 100, TRUE); if (ret == WAIT_TIMEOUT) { /* * The finalizer thread refused to die. There is not much we * can do here, since the runtime is shutting down so the * state the finalizer thread depends on will vanish. */ g_warning ("Shutting down finalizer thread timed out."); timed_out = TRUE; } } if (!timed_out) { int ret; /* Wait for the thread to actually exit */ ret = guarded_wait (gc_thread->handle, INFINITE, TRUE); g_assert (ret == WAIT_OBJECT_0); mono_thread_join (GUINT_TO_POINTER (gc_thread->tid)); } g_assert (finalizer_thread_exited); } gc_thread = NULL; mono_gc_base_cleanup (); } mono_reference_queue_cleanup (); mono_coop_mutex_destroy (&finalizer_mutex); mono_coop_mutex_destroy (&reference_queue_mutex); } gboolean mono_gc_is_finalizer_internal_thread (MonoInternalThread *thread) { return thread == gc_thread; } /** * mono_gc_is_finalizer_thread: * @thread: the thread to test. * * In Mono objects are finalized asynchronously on a separate thread. * This routine tests whether the @thread argument represents the * finalization thread. * * Returns: TRUE if @thread is the finalization thread. */ gboolean mono_gc_is_finalizer_thread (MonoThread *thread) { return mono_gc_is_finalizer_internal_thread (thread->internal_thread); } #if defined(__MACH__) static pthread_t mach_exception_thread; void mono_gc_register_mach_exception_thread (pthread_t thread) { mach_exception_thread = thread; } pthread_t mono_gc_get_mach_exception_thread (void) { return mach_exception_thread; } #endif static MonoReferenceQueue *ref_queues; static void ref_list_remove_element (RefQueueEntry **prev, RefQueueEntry *element) { do { /* Guard if head is changed concurrently. */ while (*prev != element) prev = &(*prev)->next; } while (prev && InterlockedCompareExchangePointer ((volatile gpointer *)prev, element->next, element) != element); } static void ref_list_push (RefQueueEntry **head, RefQueueEntry *value) { RefQueueEntry *current; do { current = *head; value->next = current; STORE_STORE_FENCE; /*Must make sure the previous store is visible before the CAS. */ } while (InterlockedCompareExchangePointer ((volatile gpointer *)head, value, current) != current); } static void reference_queue_proccess (MonoReferenceQueue *queue) { RefQueueEntry **iter = &queue->queue; RefQueueEntry *entry; while ((entry = *iter)) { if (queue->should_be_deleted || !mono_gchandle_get_target (entry->gchandle)) { mono_gchandle_free ((guint32)entry->gchandle); ref_list_remove_element (iter, entry); queue->callback (entry->user_data); g_free (entry); } else { iter = &entry->next; } } } static void reference_queue_proccess_all (void) { MonoReferenceQueue **iter; MonoReferenceQueue *queue = ref_queues; for (; queue; queue = queue->next) reference_queue_proccess (queue); restart: mono_coop_mutex_lock (&reference_queue_mutex); for (iter = &ref_queues; *iter;) { queue = *iter; if (!queue->should_be_deleted) { iter = &queue->next; continue; } if (queue->queue) { mono_coop_mutex_unlock (&reference_queue_mutex); reference_queue_proccess (queue); goto restart; } *iter = queue->next; g_free (queue); } mono_coop_mutex_unlock (&reference_queue_mutex); } static void mono_reference_queue_cleanup (void) { MonoReferenceQueue *queue = ref_queues; for (; queue; queue = queue->next) queue->should_be_deleted = TRUE; reference_queue_proccess_all (); } static void reference_queue_clear_for_domain (MonoDomain *domain) { MonoReferenceQueue *queue = ref_queues; for (; queue; queue = queue->next) { RefQueueEntry **iter = &queue->queue; RefQueueEntry *entry; while ((entry = *iter)) { if (entry->domain == domain) { mono_gchandle_free ((guint32)entry->gchandle); ref_list_remove_element (iter, entry); queue->callback (entry->user_data); g_free (entry); } else { iter = &entry->next; } } } } /** * mono_gc_reference_queue_new: * @callback callback used when processing collected entries. * * Create a new reference queue used to process collected objects. * A reference queue let you add a pair of (managed object, user data) * using the mono_gc_reference_queue_add method. * * Once the managed object is collected @callback will be called * in the finalizer thread with 'user data' as argument. * * The callback is called from the finalizer thread without any locks held. * When a AppDomain is unloaded, all callbacks for objects belonging to it * will be invoked. * * @returns the new queue. */ MonoReferenceQueue* mono_gc_reference_queue_new (mono_reference_queue_callback callback) { MonoReferenceQueue *res = g_new0 (MonoReferenceQueue, 1); res->callback = callback; mono_coop_mutex_lock (&reference_queue_mutex); res->next = ref_queues; ref_queues = res; mono_coop_mutex_unlock (&reference_queue_mutex); return res; } /** * mono_gc_reference_queue_add: * @queue the queue to add the reference to. * @obj the object to be watched for collection * @user_data parameter to be passed to the queue callback * * Queue an object to be watched for collection, when the @obj is * collected, the callback that was registered for the @queue will * be invoked with @user_data as argument. * * @returns false if the queue is scheduled to be freed. */ gboolean mono_gc_reference_queue_add (MonoReferenceQueue *queue, MonoObject *obj, void *user_data) { MonoError error; RefQueueEntry *entry; if (queue->should_be_deleted) return FALSE; entry = g_new0 (RefQueueEntry, 1); entry->user_data = user_data; entry->domain = mono_object_domain (obj); entry->gchandle = mono_gchandle_new_weakref (obj, TRUE); mono_object_register_finalizer (obj, &error); mono_error_assert_ok (&error); ref_list_push (&queue->queue, entry); return TRUE; } /** * mono_gc_reference_queue_free: * @queue the queue that should be freed. * * This operation signals that @queue should be freed. This operation is deferred * as it happens on the finalizer thread. * * After this call, no further objects can be queued. It's the responsibility of the * caller to make sure that no further attempt to access queue will be made. */ void mono_gc_reference_queue_free (MonoReferenceQueue *queue) { queue->should_be_deleted = TRUE; }