2 * metadata/gc.c: GC icalls.
4 * Author: Paolo Molaro <lupus@ximian.com>
6 * Copyright 2002-2003 Ximian, Inc (http://www.ximian.com)
7 * Copyright 2004-2009 Novell, Inc (http://www.novell.com)
8 * Copyright 2012 Xamarin Inc (http://www.xamarin.com)
15 #include <mono/metadata/gc-internal.h>
16 #include <mono/metadata/mono-gc.h>
17 #include <mono/metadata/threads.h>
18 #include <mono/metadata/tabledefs.h>
19 #include <mono/metadata/exception.h>
20 #include <mono/metadata/profiler-private.h>
21 #include <mono/metadata/domain-internals.h>
22 #include <mono/metadata/class-internals.h>
23 #include <mono/metadata/metadata-internals.h>
24 #include <mono/metadata/mono-mlist.h>
25 #include <mono/metadata/threadpool.h>
26 #include <mono/metadata/threadpool-internals.h>
27 #include <mono/metadata/threads-types.h>
28 #include <mono/sgen/sgen-conf.h>
29 #include <mono/utils/mono-logger-internal.h>
30 #include <mono/metadata/gc-internal.h>
31 #include <mono/metadata/marshal.h> /* for mono_delegate_free_ftnptr () */
32 #include <mono/metadata/attach.h>
33 #include <mono/metadata/console-io.h>
34 #include <mono/utils/mono-semaphore.h>
35 #include <mono/utils/mono-memory-model.h>
36 #include <mono/utils/mono-counters.h>
37 #include <mono/utils/mono-time.h>
38 #include <mono/utils/dtrace.h>
39 #include <mono/utils/mono-threads.h>
40 #include <mono/utils/atomic.h>
46 typedef struct DomainFinalizationReq {
49 } DomainFinalizationReq;
51 static gboolean gc_disabled = FALSE;
53 static gboolean finalizing_root_domain = FALSE;
55 gboolean log_finalizers = FALSE;
56 gboolean do_not_finalize = FALSE;
58 #define mono_finalizer_lock() mono_mutex_lock (&finalizer_mutex)
59 #define mono_finalizer_unlock() mono_mutex_unlock (&finalizer_mutex)
60 static mono_mutex_t finalizer_mutex;
61 static mono_mutex_t reference_queue_mutex;
63 static GSList *domains_to_finalize= NULL;
64 static MonoMList *threads_to_finalize = NULL;
66 static gboolean finalizer_thread_exited;
67 static int num_to_finalize;
69 /* These use finalizer_mutex */
70 /* Used to wait for finalizer_thread_exited to become TRUE */
71 static mono_cond_t exited_cond;
72 /* Used to wait for num_to_finalize to become > 0 */
73 static mono_cond_t finalizer_cond;
75 static MonoInternalThread *gc_thread;
77 static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*));
79 static void mono_gchandle_set_target (guint32 gchandle, MonoObject *obj);
81 static void reference_queue_proccess_all (void);
82 static void mono_reference_queue_cleanup (void);
83 static void reference_queue_clear_for_domain (MonoDomain *domain);
84 static HANDLE pending_done_event;
87 guarded_wait (HANDLE handle, guint32 timeout, gboolean alertable)
92 result = WaitForSingleObjectEx (handle, timeout, alertable);
99 add_thread_to_finalize (MonoInternalThread *thread)
101 mono_finalizer_lock ();
102 if (!threads_to_finalize)
103 MONO_GC_REGISTER_ROOT_SINGLE (threads_to_finalize);
104 threads_to_finalize = mono_mlist_append (threads_to_finalize, (MonoObject*)thread);
105 mono_finalizer_unlock ();
108 static gboolean suspend_finalizers = FALSE;
110 * actually, we might want to queue the finalize requests in a separate thread,
111 * but we need to be careful about the execution domain of the thread...
114 mono_gc_run_finalize (void *obj, void *data)
119 MonoObject *exc = NULL;
124 MonoMethod* finalizer = NULL;
125 MonoDomain *caller_domain = mono_domain_get ();
127 RuntimeInvokeFunction runtime_invoke;
129 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
132 g_log ("mono-gc-finalizers", G_LOG_LEVEL_DEBUG, "<%s at %p> Starting finalizer checks.", o->vtable->klass->name, o);
134 if (suspend_finalizers)
137 domain = o->vtable->domain;
140 mono_domain_finalizers_lock (domain);
142 o2 = g_hash_table_lookup (domain->finalizable_objects_hash, o);
144 mono_domain_finalizers_unlock (domain);
147 /* Already finalized somehow */
151 /* make sure the finalizer is not called again if the object is resurrected */
152 object_register_finalizer (obj, NULL);
155 g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Registered finalizer as processed.", o->vtable->klass->name, o);
157 if (o->vtable->klass == mono_defaults.internal_thread_class) {
158 MonoInternalThread *t = (MonoInternalThread*)o;
160 if (mono_gc_is_finalizer_internal_thread (t))
161 /* Avoid finalizing ourselves */
164 if (t->threadpool_thread && finalizing_root_domain) {
165 /* Don't finalize threadpool threads when
166 shutting down - they're finalized when the
167 threadpool shuts down. */
168 add_thread_to_finalize (t);
173 if (o->vtable->klass->image == mono_defaults.corlib && !strcmp (o->vtable->klass->name, "DynamicMethod") && finalizing_root_domain) {
175 * These can't be finalized during unloading/shutdown, since that would
176 * free the native code which can still be referenced by other
178 * FIXME: This is not perfect, objects dying at the same time as
179 * dynamic methods can still reference them even when !shutdown.
184 if (mono_runtime_get_no_exec ())
187 /* speedup later... and use a timeout */
188 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
190 /* Use _internal here, since this thread can enter a doomed appdomain */
191 mono_domain_set_internal (mono_object_domain (o));
193 /* delegates that have a native function pointer allocated are
194 * registered for finalization, but they don't have a Finalize
195 * method, because in most cases it's not needed and it's just a waste.
197 if (o->vtable->klass->delegate) {
198 MonoDelegate* del = (MonoDelegate*)o;
199 if (del->delegate_trampoline)
200 mono_delegate_free_ftnptr ((MonoDelegate*)o);
201 mono_domain_set_internal (caller_domain);
205 finalizer = mono_class_get_finalizer (o->vtable->klass);
208 /* If object has a CCW but has no finalizer, it was only
209 * registered for finalization in order to free the CCW.
210 * Else it needs the regular finalizer run.
211 * FIXME: what to do about ressurection and suppression
212 * of finalizer on object with CCW.
214 if (mono_marshal_free_ccw (o) && !finalizer) {
215 mono_domain_set_internal (caller_domain);
221 * To avoid the locking plus the other overhead of mono_runtime_invoke (),
222 * create and precompile a wrapper which calls the finalize method using
226 g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Compiling finalizer.", o->vtable->klass->name, o);
228 if (!domain->finalize_runtime_invoke) {
229 MonoMethod *invoke = mono_marshal_get_runtime_invoke (mono_class_get_method_from_name_flags (mono_defaults.object_class, "Finalize", 0, 0), TRUE);
231 domain->finalize_runtime_invoke = mono_compile_method (invoke);
234 runtime_invoke = domain->finalize_runtime_invoke;
236 mono_runtime_class_init (o->vtable);
238 if (G_UNLIKELY (MONO_GC_FINALIZE_INVOKE_ENABLED ())) {
239 MONO_GC_FINALIZE_INVOKE ((unsigned long)o, mono_object_get_size (o),
240 o->vtable->klass->name_space, o->vtable->klass->name);
244 g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Calling finalizer.", o->vtable->klass->name, o);
246 runtime_invoke (o, NULL, &exc, NULL);
249 g_log ("mono-gc-finalizers", G_LOG_LEVEL_MESSAGE, "<%s at %p> Returned from finalizer.", o->vtable->klass->name, o);
252 mono_internal_thread_unhandled_exception (exc);
254 mono_domain_set_internal (caller_domain);
258 mono_gc_finalize_threadpool_threads (void)
260 while (threads_to_finalize) {
261 MonoInternalThread *thread = (MonoInternalThread*) mono_mlist_get_data (threads_to_finalize);
263 /* Force finalization of the thread. */
264 thread->threadpool_thread = FALSE;
265 mono_object_register_finalizer ((MonoObject*)thread);
267 mono_gc_run_finalize (thread, NULL);
269 threads_to_finalize = mono_mlist_next (threads_to_finalize);
274 mono_gc_out_of_memory (size_t size)
277 * we could allocate at program startup some memory that we could release
278 * back to the system at this point if we're really low on memory (ie, size is
279 * lower than the memory we set apart)
281 mono_raise_exception (mono_domain_get ()->out_of_memory_ex);
287 * Some of our objects may point to a different address than the address returned by GC_malloc()
288 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
289 * This also means that in the callback we need to adjust the pointer to get back the real
291 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
292 * since that, too, can cause the underlying pointer to be offset.
295 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
300 mono_raise_exception (mono_get_exception_argument_null ("obj"));
302 domain = obj->vtable->domain;
305 if (mono_domain_is_unloading (domain) && (callback != NULL))
307 * Can't register finalizers in a dying appdomain, since they
308 * could be invoked after the appdomain has been unloaded.
312 mono_domain_finalizers_lock (domain);
315 g_hash_table_insert (domain->finalizable_objects_hash, obj, obj);
317 g_hash_table_remove (domain->finalizable_objects_hash, obj);
319 mono_domain_finalizers_unlock (domain);
321 mono_gc_register_for_finalization (obj, callback);
322 #elif defined(HAVE_SGEN_GC)
324 * If we register finalizers for domains that are unloading we might
325 * end up running them while or after the domain is being cleared, so
326 * the objects will not be valid anymore.
328 if (!mono_domain_is_unloading (domain))
329 mono_gc_register_for_finalization (obj, callback);
334 * mono_object_register_finalizer:
335 * @obj: object to register
337 * Records that object @obj has a finalizer, this will call the
338 * Finalize method when the garbage collector disposes the object.
342 mono_object_register_finalizer (MonoObject *obj)
344 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
345 object_register_finalizer (obj, mono_gc_run_finalize);
349 * mono_domain_finalize:
350 * @domain: the domain to finalize
351 * @timeout: msects to wait for the finalization to complete, -1 to wait indefinitely
353 * Request finalization of all finalizable objects inside @domain. Wait
354 * @timeout msecs for the finalization to complete.
356 * Returns: TRUE if succeeded, FALSE if there was a timeout
360 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
362 DomainFinalizationReq *req;
365 MonoInternalThread *thread = mono_thread_internal_current ();
367 #if defined(__native_client__)
371 if (mono_thread_internal_current () == gc_thread)
372 /* We are called from inside a finalizer, not much we can do here */
376 * No need to create another thread 'cause the finalizer thread
377 * is still working and will take care of running the finalizers
383 /* We don't support domain finalization without a GC */
384 if (mono_gc_is_null ())
387 mono_gc_collect (mono_gc_max_generation ());
389 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
390 if (done_event == NULL) {
394 req = g_new0 (DomainFinalizationReq, 1);
395 req->domain = domain;
396 req->done_event = done_event;
398 if (domain == mono_get_root_domain ())
399 finalizing_root_domain = TRUE;
401 mono_finalizer_lock ();
403 domains_to_finalize = g_slist_append (domains_to_finalize, req);
405 mono_finalizer_unlock ();
407 /* Tell the finalizer thread to finalize this appdomain */
408 mono_gc_finalize_notify ();
414 res = guarded_wait (done_event, timeout, TRUE);
415 /* printf ("WAIT RES: %d.\n", res); */
417 if (res == WAIT_IO_COMPLETION) {
418 if ((thread->state & (ThreadState_StopRequested | ThreadState_SuspendRequested)) != 0)
420 } else if (res == WAIT_TIMEOUT) {
421 /* We leak the handle here */
428 CloseHandle (done_event);
430 if (domain == mono_get_root_domain ()) {
431 mono_thread_pool_cleanup ();
432 mono_gc_finalize_threadpool_threads ();
439 ves_icall_System_GC_InternalCollect (int generation)
441 mono_gc_collect (generation);
445 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
448 mono_gc_collect (mono_gc_max_generation ());
449 return mono_gc_get_used_size ();
453 ves_icall_System_GC_KeepAlive (MonoObject *obj)
461 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
463 MONO_CHECK_ARG_NULL (obj,);
465 object_register_finalizer (obj, mono_gc_run_finalize);
469 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
471 MONO_CHECK_ARG_NULL (obj,);
473 /* delegates have no finalizers, but we register them to deal with the
474 * unmanaged->managed trampoline. We don't let the user suppress it
475 * otherwise we'd leak it.
477 if (obj->vtable->klass->delegate)
480 /* FIXME: Need to handle case where obj has COM Callable Wrapper
481 * generated for it that needs cleaned up, but user wants to suppress
482 * their derived object finalizer. */
484 object_register_finalizer (obj, NULL);
488 ves_icall_System_GC_WaitForPendingFinalizers (void)
490 if (mono_gc_is_null ())
493 if (!mono_gc_pending_finalizers ())
496 if (mono_thread_internal_current () == gc_thread)
497 /* Avoid deadlocks */
501 If the finalizer thread is not live, lets pretend no finalizers are pending since the current thread might
502 be the one responsible for starting it up.
504 if (gc_thread == NULL)
507 /* Can't use cond vars here, since they don't contain the wapi interrupt logic */
509 ResetEvent (pending_done_event);
510 mono_gc_finalize_notify ();
511 /* g_print ("Waiting for pending finalizers....\n"); */
512 guarded_wait (pending_done_event, INFINITE, TRUE);
513 /* g_print ("Done pending....\n"); */
517 ves_icall_System_GC_register_ephemeron_array (MonoObject *array)
520 if (!mono_gc_ephemeron_array_add (array)) {
521 mono_set_pending_exception (mono_object_domain (array)->out_of_memory_ex);
528 ves_icall_System_GC_get_ephemeron_tombstone (void)
530 return mono_domain_get ()->ephemeron_tombstone;
533 #define mono_allocator_lock() mono_mutex_lock (&allocator_section)
534 #define mono_allocator_unlock() mono_mutex_unlock (&allocator_section)
535 static mono_mutex_t allocator_section;
536 static mono_mutex_t handle_section;
545 static HandleType mono_gchandle_get_type (guint32 gchandle);
548 ves_icall_System_GCHandle_GetTarget (guint32 handle)
550 return mono_gchandle_get_target (handle);
554 * if type == -1, change the target of the handle, otherwise allocate a new handle.
557 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
560 mono_gchandle_set_target (handle, obj);
561 /* the handle doesn't change */
566 return mono_gchandle_new_weakref (obj, FALSE);
567 case HANDLE_WEAK_TRACK:
568 return mono_gchandle_new_weakref (obj, TRUE);
570 return mono_gchandle_new (obj, FALSE);
572 return mono_gchandle_new (obj, TRUE);
574 g_assert_not_reached ();
580 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
582 mono_gchandle_free (handle);
586 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
590 if (mono_gchandle_get_type (handle) != HANDLE_PINNED)
592 obj = mono_gchandle_get_target (handle);
594 MonoClass *klass = mono_object_class (obj);
595 if (klass == mono_defaults.string_class) {
596 return mono_string_chars ((MonoString*)obj);
597 } else if (klass->rank) {
598 return mono_array_addr ((MonoArray*)obj, char, 0);
600 /* the C# code will check and throw the exception */
601 /* FIXME: missing !klass->blittable test, see bug #61134 */
602 if ((klass->flags & TYPE_ATTRIBUTE_LAYOUT_MASK) == TYPE_ATTRIBUTE_AUTO_LAYOUT)
604 return (char*)obj + sizeof (MonoObject);
611 ves_icall_Mono_Runtime_SetGCAllowSynchronousMajor (MonoBoolean flag)
613 return mono_gc_set_allow_synchronous_major (flag);
621 guint slot_hint : 24; /* starting slot for search */
622 /* 2^16 appdomains should be enough for everyone (though I know I'll regret this in 20 years) */
623 /* we alloc this only for weak refs, since we can get the domain directly in the other cases */
627 /* weak and weak-track arrays will be allocated in malloc memory
629 static HandleData gc_handles [] = {
630 {NULL, NULL, 0, HANDLE_WEAK, 0},
631 {NULL, NULL, 0, HANDLE_WEAK_TRACK, 0},
632 {NULL, NULL, 0, HANDLE_NORMAL, 0},
633 {NULL, NULL, 0, HANDLE_PINNED, 0}
636 #define lock_handles(handles) mono_mutex_lock (&handle_section)
637 #define unlock_handles(handles) mono_mutex_unlock (&handle_section)
640 find_first_unset (guint32 bitmap)
643 for (i = 0; i < 32; ++i) {
644 if (!(bitmap & (1 << i)))
651 make_root_descr_all_refs (int numbits, gboolean pinned)
657 return mono_gc_make_root_descr_all_refs (numbits);
661 alloc_handle (HandleData *handles, MonoObject *obj, gboolean track)
665 lock_handles (handles);
666 if (!handles->size) {
668 if (handles->type > HANDLE_WEAK_TRACK) {
669 handles->entries = mono_gc_alloc_fixed (sizeof (gpointer) * handles->size, make_root_descr_all_refs (handles->size, handles->type == HANDLE_PINNED));
671 handles->entries = g_malloc0 (sizeof (gpointer) * handles->size);
672 handles->domain_ids = g_malloc0 (sizeof (guint16) * handles->size);
674 handles->bitmap = g_malloc0 (handles->size / 8);
677 for (slot = handles->slot_hint; slot < handles->size / 32; ++slot) {
678 if (handles->bitmap [slot] != 0xffffffff) {
679 i = find_first_unset (handles->bitmap [slot]);
680 handles->slot_hint = slot;
684 if (i == -1 && handles->slot_hint != 0) {
685 for (slot = 0; slot < handles->slot_hint; ++slot) {
686 if (handles->bitmap [slot] != 0xffffffff) {
687 i = find_first_unset (handles->bitmap [slot]);
688 handles->slot_hint = slot;
695 guint32 new_size = handles->size * 2; /* always double: we memset to 0 based on this below */
697 /* resize and copy the bitmap */
698 new_bitmap = g_malloc0 (new_size / 8);
699 memcpy (new_bitmap, handles->bitmap, handles->size / 8);
700 g_free (handles->bitmap);
701 handles->bitmap = new_bitmap;
703 /* resize and copy the entries */
704 if (handles->type > HANDLE_WEAK_TRACK) {
707 entries = mono_gc_alloc_fixed (sizeof (gpointer) * new_size, make_root_descr_all_refs (new_size, handles->type == HANDLE_PINNED));
708 mono_gc_memmove_aligned (entries, handles->entries, sizeof (gpointer) * handles->size);
710 mono_gc_free_fixed (handles->entries);
711 handles->entries = entries;
715 domain_ids = g_malloc0 (sizeof (guint16) * new_size);
716 entries = g_malloc0 (sizeof (gpointer) * new_size);
717 memcpy (domain_ids, handles->domain_ids, sizeof (guint16) * handles->size);
718 for (i = 0; i < handles->size; ++i) {
719 MonoObject *obj = mono_gc_weak_link_get (&(handles->entries [i]));
721 mono_gc_weak_link_add (&(entries [i]), obj, track);
722 mono_gc_weak_link_remove (&(handles->entries [i]), track);
724 g_assert (!handles->entries [i]);
727 g_free (handles->entries);
728 g_free (handles->domain_ids);
729 handles->entries = entries;
730 handles->domain_ids = domain_ids;
733 /* set i and slot to the next free position */
735 slot = (handles->size + 1) / 32;
736 handles->slot_hint = handles->size + 1;
737 handles->size = new_size;
739 handles->bitmap [slot] |= 1 << i;
740 slot = slot * 32 + i;
741 handles->entries [slot] = NULL;
742 if (handles->type <= HANDLE_WEAK_TRACK) {
743 /*FIXME, what to use when obj == null?*/
744 handles->domain_ids [slot] = (obj ? mono_object_get_domain (obj) : mono_domain_get ())->domain_id;
746 mono_gc_weak_link_add (&(handles->entries [slot]), obj, track);
748 handles->entries [slot] = obj;
751 #ifndef DISABLE_PERFCOUNTERS
752 mono_perfcounters->gc_num_handles++;
754 unlock_handles (handles);
755 /*g_print ("allocated entry %d of type %d to object %p (in slot: %p)\n", slot, handles->type, obj, handles->entries [slot]);*/
756 res = (slot << 3) | (handles->type + 1);
757 mono_profiler_gc_handle (MONO_PROFILER_GC_HANDLE_CREATED, handles->type, res, obj);
763 * @obj: managed object to get a handle for
764 * @pinned: whether the object should be pinned
766 * This returns a handle that wraps the object, this is used to keep a
767 * reference to a managed object from the unmanaged world and preventing the
768 * object from being disposed.
770 * If @pinned is false the address of the object can not be obtained, if it is
771 * true the address of the object can be obtained. This will also pin the
772 * object so it will not be possible by a moving garbage collector to move the
775 * Returns: a handle that can be used to access the object from
779 mono_gchandle_new (MonoObject *obj, gboolean pinned)
781 return alloc_handle (&gc_handles [pinned? HANDLE_PINNED: HANDLE_NORMAL], obj, FALSE);
785 * mono_gchandle_new_weakref:
786 * @obj: managed object to get a handle for
787 * @pinned: whether the object should be pinned
789 * This returns a weak handle that wraps the object, this is used to
790 * keep a reference to a managed object from the unmanaged world.
791 * Unlike the mono_gchandle_new the object can be reclaimed by the
792 * garbage collector. In this case the value of the GCHandle will be
795 * If @pinned is false the address of the object can not be obtained, if it is
796 * true the address of the object can be obtained. This will also pin the
797 * object so it will not be possible by a moving garbage collector to move the
800 * Returns: a handle that can be used to access the object from
804 mono_gchandle_new_weakref (MonoObject *obj, gboolean track_resurrection)
806 guint32 handle = alloc_handle (&gc_handles [track_resurrection? HANDLE_WEAK_TRACK: HANDLE_WEAK], obj, track_resurrection);
812 mono_gchandle_get_type (guint32 gchandle)
814 guint type = (gchandle & 7) - 1;
820 * mono_gchandle_get_target:
821 * @gchandle: a GCHandle's handle.
823 * The handle was previously created by calling mono_gchandle_new or
824 * mono_gchandle_new_weakref.
826 * Returns a pointer to the MonoObject represented by the handle or
827 * NULL for a collected object if using a weakref handle.
830 mono_gchandle_get_target (guint32 gchandle)
832 guint slot = gchandle >> 3;
833 guint type = (gchandle & 7) - 1;
834 HandleData *handles = &gc_handles [type];
835 MonoObject *obj = NULL;
838 lock_handles (handles);
839 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
840 if (handles->type <= HANDLE_WEAK_TRACK) {
841 obj = mono_gc_weak_link_get (&handles->entries [slot]);
843 obj = handles->entries [slot];
846 /* print a warning? */
848 unlock_handles (handles);
849 /*g_print ("get target of entry %d of type %d: %p\n", slot, handles->type, obj);*/
854 mono_gchandle_set_target (guint32 gchandle, MonoObject *obj)
856 guint slot = gchandle >> 3;
857 guint type = (gchandle & 7) - 1;
858 HandleData *handles = &gc_handles [type];
862 lock_handles (handles);
863 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
864 if (handles->type <= HANDLE_WEAK_TRACK) {
865 if (handles->entries [slot])
866 mono_gc_weak_link_remove (&handles->entries [slot], handles->type == HANDLE_WEAK_TRACK);
868 mono_gc_weak_link_add (&handles->entries [slot], obj, handles->type == HANDLE_WEAK_TRACK);
869 /*FIXME, what to use when obj == null?*/
870 handles->domain_ids [slot] = (obj ? mono_object_get_domain (obj) : mono_domain_get ())->domain_id;
872 handles->entries [slot] = obj;
875 /* print a warning? */
877 /*g_print ("changed entry %d of type %d to object %p (in slot: %p)\n", slot, handles->type, obj, handles->entries [slot]);*/
878 unlock_handles (handles);
882 * mono_gchandle_is_in_domain:
883 * @gchandle: a GCHandle's handle.
884 * @domain: An application domain.
886 * Returns: true if the object wrapped by the @gchandle belongs to the specific @domain.
889 mono_gchandle_is_in_domain (guint32 gchandle, MonoDomain *domain)
891 guint slot = gchandle >> 3;
892 guint type = (gchandle & 7) - 1;
893 HandleData *handles = &gc_handles [type];
894 gboolean result = FALSE;
897 lock_handles (handles);
898 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
899 if (handles->type <= HANDLE_WEAK_TRACK) {
900 result = domain->domain_id == handles->domain_ids [slot];
903 obj = handles->entries [slot];
907 result = domain == mono_object_domain (obj);
910 /* print a warning? */
912 unlock_handles (handles);
917 * mono_gchandle_free:
918 * @gchandle: a GCHandle's handle.
920 * Frees the @gchandle handle. If there are no outstanding
921 * references, the garbage collector can reclaim the memory of the
925 mono_gchandle_free (guint32 gchandle)
927 guint slot = gchandle >> 3;
928 guint type = (gchandle & 7) - 1;
929 HandleData *handles = &gc_handles [type];
933 lock_handles (handles);
934 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
935 if (handles->type <= HANDLE_WEAK_TRACK) {
936 if (handles->entries [slot])
937 mono_gc_weak_link_remove (&handles->entries [slot], handles->type == HANDLE_WEAK_TRACK);
939 handles->entries [slot] = NULL;
941 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
943 /* print a warning? */
945 #ifndef DISABLE_PERFCOUNTERS
946 mono_perfcounters->gc_num_handles--;
948 /*g_print ("freed entry %d of type %d\n", slot, handles->type);*/
949 unlock_handles (handles);
950 mono_profiler_gc_handle (MONO_PROFILER_GC_HANDLE_DESTROYED, handles->type, gchandle, NULL);
954 * mono_gchandle_free_domain:
955 * @domain: domain that is unloading
957 * Function used internally to cleanup any GC handle for objects belonging
958 * to the specified domain during appdomain unload.
961 mono_gchandle_free_domain (MonoDomain *domain)
965 for (type = 0; type < 3; ++type) {
967 HandleData *handles = &gc_handles [type];
968 lock_handles (handles);
969 for (slot = 0; slot < handles->size; ++slot) {
970 if (!(handles->bitmap [slot / 32] & (1 << (slot % 32))))
972 if (type <= HANDLE_WEAK_TRACK) {
973 if (domain->domain_id == handles->domain_ids [slot]) {
974 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
975 if (handles->entries [slot])
976 mono_gc_weak_link_remove (&handles->entries [slot], handles->type == HANDLE_WEAK_TRACK);
979 if (handles->entries [slot] && mono_object_domain (handles->entries [slot]) == domain) {
980 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
981 handles->entries [slot] = NULL;
985 unlock_handles (handles);
991 mono_gc_GCHandle_CheckCurrentDomain (guint32 gchandle)
993 return mono_gchandle_is_in_domain (gchandle, mono_domain_get ());
996 static volatile gboolean finished=FALSE;
999 mono_gc_finalize_notify (void)
1002 g_message ( "%s: prodding finalizer", __func__);
1005 if (mono_gc_is_null ())
1008 mono_mutex_lock (&finalizer_mutex);
1010 mono_cond_signal (&finalizer_cond);
1011 mono_mutex_unlock (&finalizer_mutex);
1014 #ifdef HAVE_BOEHM_GC
1017 collect_objects (gpointer key, gpointer value, gpointer user_data)
1019 GPtrArray *arr = (GPtrArray*)user_data;
1020 g_ptr_array_add (arr, key);
1026 * finalize_domain_objects:
1028 * Run the finalizers of all finalizable objects in req->domain.
1031 finalize_domain_objects (DomainFinalizationReq *req)
1033 MonoDomain *domain = req->domain;
1036 #define NUM_FOBJECTS 64
1037 MonoObject *to_finalize [NUM_FOBJECTS];
1041 /* Process finalizers which are already in the queue */
1042 mono_gc_invoke_finalizers ();
1044 #ifdef HAVE_BOEHM_GC
1045 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
1049 * Since the domain is unloading, nobody is allowed to put
1050 * new entries into the hash table. But finalize_object might
1051 * remove entries from the hash table, so we make a copy.
1053 objs = g_ptr_array_new ();
1054 g_hash_table_foreach (domain->finalizable_objects_hash, collect_objects, objs);
1055 /* printf ("FINALIZING %d OBJECTS.\n", objs->len); */
1057 for (i = 0; i < objs->len; ++i) {
1058 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
1059 /* FIXME: Avoid finalizing threads, etc */
1060 mono_gc_run_finalize (o, 0);
1063 g_ptr_array_free (objs, TRUE);
1065 #elif defined(HAVE_SGEN_GC)
1066 while ((count = mono_gc_finalizers_for_domain (domain, to_finalize, NUM_FOBJECTS))) {
1068 for (i = 0; i < count; ++i) {
1069 mono_gc_run_finalize (to_finalize [i], 0);
1074 /* cleanup the reference queue */
1075 reference_queue_clear_for_domain (domain);
1077 /* printf ("DONE.\n"); */
1078 SetEvent (req->done_event);
1080 /* The event is closed in mono_domain_finalize if we get here */
1085 finalizer_thread (gpointer unused)
1089 * Wait to be notified that there's at least one
1092 g_assert (mono_domain_get () == mono_get_root_domain ());
1094 gboolean has_work = FALSE;
1096 mono_gc_set_skip_thread (TRUE);
1097 MONO_PREPARE_BLOCKING;
1098 mono_mutex_lock (&finalizer_mutex);
1099 if (!num_to_finalize)
1100 mono_cond_wait (&finalizer_cond, &finalizer_mutex);
1103 mono_mutex_unlock (&finalizer_mutex);
1104 MONO_FINISH_BLOCKING;
1105 mono_gc_set_skip_thread (FALSE);
1107 if (has_work || finished)
1111 mono_threads_perform_thread_dump ();
1113 mono_console_handle_async_ops ();
1115 #ifndef DISABLE_ATTACH
1116 mono_attach_maybe_start ();
1119 if (domains_to_finalize) {
1120 mono_finalizer_lock ();
1121 if (domains_to_finalize) {
1122 DomainFinalizationReq *req = domains_to_finalize->data;
1123 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
1124 mono_finalizer_unlock ();
1126 finalize_domain_objects (req);
1128 mono_finalizer_unlock ();
1132 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
1133 * before the domain is unloaded.
1135 mono_gc_invoke_finalizers ();
1137 mono_threads_join_threads ();
1139 reference_queue_proccess_all ();
1141 /* Avoid posting the pending done event until there are pending finalizers */
1142 mono_mutex_lock (&finalizer_mutex);
1144 if (num_to_finalize == 0)
1145 SetEvent (pending_done_event);
1146 mono_mutex_unlock (&finalizer_mutex);
1149 mono_finalizer_lock ();
1150 finalizer_thread_exited = TRUE;
1151 mono_cond_signal (&exited_cond);
1152 mono_finalizer_unlock ();
1157 #ifndef LAZY_GC_THREAD_CREATION
1161 mono_gc_init_finalizer_thread (void)
1163 gc_thread = mono_thread_create_internal (mono_domain_get (), finalizer_thread, NULL, FALSE, 0);
1164 ves_icall_System_Threading_Thread_SetName_internal (gc_thread, mono_string_new (mono_domain_get (), "Finalizer"));
1170 mono_mutex_init_recursive (&handle_section);
1171 mono_mutex_init_recursive (&allocator_section);
1173 mono_mutex_init_recursive (&finalizer_mutex);
1174 mono_mutex_init_recursive (&reference_queue_mutex);
1176 MONO_GC_REGISTER_ROOT_FIXED (gc_handles [HANDLE_NORMAL].entries);
1177 MONO_GC_REGISTER_ROOT_FIXED (gc_handles [HANDLE_PINNED].entries);
1179 mono_counters_register ("Minor GC collections", MONO_COUNTER_GC | MONO_COUNTER_UINT, &gc_stats.minor_gc_count);
1180 mono_counters_register ("Major GC collections", MONO_COUNTER_GC | MONO_COUNTER_UINT, &gc_stats.major_gc_count);
1181 mono_counters_register ("Minor GC time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.minor_gc_time);
1182 mono_counters_register ("Major GC time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.major_gc_time);
1183 mono_counters_register ("Major GC time concurrent", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &gc_stats.major_gc_time_concurrent);
1185 mono_gc_base_init ();
1187 if (mono_gc_is_disabled ()) {
1192 mono_cond_init (&finalizer_cond, 0);
1193 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
1194 g_assert (pending_done_event);
1195 mono_cond_init (&exited_cond, 0);
1197 #ifndef LAZY_GC_THREAD_CREATION
1198 mono_gc_init_finalizer_thread ();
1203 mono_gc_cleanup (void)
1206 g_message ("%s: cleaning up finalizer", __func__);
1209 if (mono_gc_is_null ())
1214 if (mono_thread_internal_current () != gc_thread) {
1215 gboolean timed_out = FALSE;
1216 guint32 start_ticks = mono_msec_ticks ();
1217 guint32 end_ticks = start_ticks + 2000;
1219 mono_gc_finalize_notify ();
1220 /* Finishing the finalizer thread, so wait a little bit... */
1221 /* MS seems to wait for about 2 seconds */
1222 while (!finalizer_thread_exited) {
1223 guint32 current_ticks = mono_msec_ticks ();
1226 if (current_ticks >= end_ticks)
1229 timeout = end_ticks - current_ticks;
1230 MONO_PREPARE_BLOCKING;
1231 mono_finalizer_lock ();
1232 if (!finalizer_thread_exited)
1233 mono_cond_timedwait_ms (&exited_cond, &finalizer_mutex, timeout);
1234 mono_finalizer_unlock ();
1235 MONO_FINISH_BLOCKING;
1238 if (!finalizer_thread_exited) {
1241 /* Set a flag which the finalizer thread can check */
1242 suspend_finalizers = TRUE;
1244 /* Try to abort the thread, in the hope that it is running managed code */
1245 mono_thread_internal_stop (gc_thread);
1247 /* Wait for it to stop */
1248 ret = guarded_wait (gc_thread->handle, 100, TRUE);
1250 if (ret == WAIT_TIMEOUT) {
1252 * The finalizer thread refused to die. There is not much we
1253 * can do here, since the runtime is shutting down so the
1254 * state the finalizer thread depends on will vanish.
1256 g_warning ("Shutting down finalizer thread timed out.");
1264 /* Wait for the thread to actually exit */
1265 ret = guarded_wait (gc_thread->handle, INFINITE, TRUE);
1266 g_assert (ret == WAIT_OBJECT_0);
1268 mono_thread_join (GUINT_TO_POINTER (gc_thread->tid));
1272 mono_gc_base_cleanup ();
1275 mono_reference_queue_cleanup ();
1277 mono_mutex_destroy (&handle_section);
1278 mono_mutex_destroy (&allocator_section);
1279 mono_mutex_destroy (&finalizer_mutex);
1280 mono_mutex_destroy (&reference_queue_mutex);
1284 mono_gc_is_finalizer_internal_thread (MonoInternalThread *thread)
1286 return thread == gc_thread;
1290 * mono_gc_is_finalizer_thread:
1291 * @thread: the thread to test.
1293 * In Mono objects are finalized asynchronously on a separate thread.
1294 * This routine tests whether the @thread argument represents the
1295 * finalization thread.
1297 * Returns true if @thread is the finalization thread.
1300 mono_gc_is_finalizer_thread (MonoThread *thread)
1302 return mono_gc_is_finalizer_internal_thread (thread->internal_thread);
1305 #if defined(__MACH__)
1306 static pthread_t mach_exception_thread;
1309 mono_gc_register_mach_exception_thread (pthread_t thread)
1311 mach_exception_thread = thread;
1315 mono_gc_get_mach_exception_thread (void)
1317 return mach_exception_thread;
1321 #ifndef HAVE_SGEN_GC
1323 mono_gc_alloc_mature (MonoVTable *vtable)
1325 return mono_object_new_specific (vtable);
1330 static MonoReferenceQueue *ref_queues;
1333 ref_list_remove_element (RefQueueEntry **prev, RefQueueEntry *element)
1336 /* Guard if head is changed concurrently. */
1337 while (*prev != element)
1338 prev = &(*prev)->next;
1339 } while (prev && InterlockedCompareExchangePointer ((void*)prev, element->next, element) != element);
1343 ref_list_push (RefQueueEntry **head, RefQueueEntry *value)
1345 RefQueueEntry *current;
1348 value->next = current;
1349 STORE_STORE_FENCE; /*Must make sure the previous store is visible before the CAS. */
1350 } while (InterlockedCompareExchangePointer ((void*)head, value, current) != current);
1354 reference_queue_proccess (MonoReferenceQueue *queue)
1356 RefQueueEntry **iter = &queue->queue;
1357 RefQueueEntry *entry;
1358 while ((entry = *iter)) {
1360 if (queue->should_be_deleted || !mono_gc_weak_link_get (&entry->dis_link)) {
1361 mono_gc_weak_link_remove (&entry->dis_link, TRUE);
1363 if (queue->should_be_deleted || !mono_gchandle_get_target (entry->gchandle)) {
1364 mono_gchandle_free ((guint32)entry->gchandle);
1366 ref_list_remove_element (iter, entry);
1367 queue->callback (entry->user_data);
1370 iter = &entry->next;
1376 reference_queue_proccess_all (void)
1378 MonoReferenceQueue **iter;
1379 MonoReferenceQueue *queue = ref_queues;
1380 for (; queue; queue = queue->next)
1381 reference_queue_proccess (queue);
1384 mono_mutex_lock (&reference_queue_mutex);
1385 for (iter = &ref_queues; *iter;) {
1387 if (!queue->should_be_deleted) {
1388 iter = &queue->next;
1392 mono_mutex_unlock (&reference_queue_mutex);
1393 reference_queue_proccess (queue);
1396 *iter = queue->next;
1399 mono_mutex_unlock (&reference_queue_mutex);
1403 mono_reference_queue_cleanup (void)
1405 MonoReferenceQueue *queue = ref_queues;
1406 for (; queue; queue = queue->next)
1407 queue->should_be_deleted = TRUE;
1408 reference_queue_proccess_all ();
1412 reference_queue_clear_for_domain (MonoDomain *domain)
1414 MonoReferenceQueue *queue = ref_queues;
1415 for (; queue; queue = queue->next) {
1416 RefQueueEntry **iter = &queue->queue;
1417 RefQueueEntry *entry;
1418 while ((entry = *iter)) {
1419 if (entry->domain == domain) {
1421 mono_gc_weak_link_remove (&entry->dis_link, TRUE);
1423 mono_gchandle_free ((guint32)entry->gchandle);
1425 ref_list_remove_element (iter, entry);
1426 queue->callback (entry->user_data);
1429 iter = &entry->next;
1435 * mono_gc_reference_queue_new:
1436 * @callback callback used when processing collected entries.
1438 * Create a new reference queue used to process collected objects.
1439 * A reference queue let you add a pair of (managed object, user data)
1440 * using the mono_gc_reference_queue_add method.
1442 * Once the managed object is collected @callback will be called
1443 * in the finalizer thread with 'user data' as argument.
1445 * The callback is called from the finalizer thread without any locks held.
1446 * When a AppDomain is unloaded, all callbacks for objects belonging to it
1449 * @returns the new queue.
1452 mono_gc_reference_queue_new (mono_reference_queue_callback callback)
1454 MonoReferenceQueue *res = g_new0 (MonoReferenceQueue, 1);
1455 res->callback = callback;
1457 mono_mutex_lock (&reference_queue_mutex);
1458 res->next = ref_queues;
1460 mono_mutex_unlock (&reference_queue_mutex);
1466 * mono_gc_reference_queue_add:
1467 * @queue the queue to add the reference to.
1468 * @obj the object to be watched for collection
1469 * @user_data parameter to be passed to the queue callback
1471 * Queue an object to be watched for collection, when the @obj is
1472 * collected, the callback that was registered for the @queue will
1473 * be invoked with @user_data as argument.
1475 * @returns false if the queue is scheduled to be freed.
1478 mono_gc_reference_queue_add (MonoReferenceQueue *queue, MonoObject *obj, void *user_data)
1480 RefQueueEntry *entry;
1481 if (queue->should_be_deleted)
1484 entry = g_new0 (RefQueueEntry, 1);
1485 entry->user_data = user_data;
1486 entry->domain = mono_object_domain (obj);
1489 mono_gc_weak_link_add (&entry->dis_link, obj, TRUE);
1491 entry->gchandle = mono_gchandle_new_weakref (obj, TRUE);
1492 mono_object_register_finalizer (obj);
1495 ref_list_push (&queue->queue, entry);
1500 * mono_gc_reference_queue_free:
1501 * @queue the queue that should be freed.
1503 * This operation signals that @queue should be freed. This operation is deferred
1504 * as it happens on the finalizer thread.
1506 * After this call, no further objects can be queued. It's the responsibility of the
1507 * caller to make sure that no further attempt to access queue will be made.
1510 mono_gc_reference_queue_free (MonoReferenceQueue *queue)
1512 queue->should_be_deleted = TRUE;