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)
16 #include <mono/metadata/gc-internal.h>
17 #include <mono/metadata/mono-gc.h>
18 #include <mono/metadata/threads.h>
19 #include <mono/metadata/tabledefs.h>
20 #include <mono/metadata/exception.h>
21 #include <mono/metadata/profiler-private.h>
22 #include <mono/metadata/domain-internals.h>
23 #include <mono/metadata/class-internals.h>
24 #include <mono/metadata/metadata-internals.h>
25 #include <mono/metadata/mono-mlist.h>
26 #include <mono/metadata/threadpool.h>
27 #include <mono/metadata/threadpool-internals.h>
28 #include <mono/metadata/threads-types.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>
41 typedef struct DomainFinalizationReq {
44 } DomainFinalizationReq;
46 #ifdef PLATFORM_WINCE /* FIXME: add accessors to gc.dll API */
47 extern void (*__imp_GC_finalizer_notifier)(void);
48 #define GC_finalizer_notifier __imp_GC_finalizer_notifier
49 extern int __imp_GC_finalize_on_demand;
50 #define GC_finalize_on_demand __imp_GC_finalize_on_demand
53 static gboolean gc_disabled = FALSE;
55 static gboolean finalizing_root_domain = FALSE;
57 #define mono_finalizer_lock() EnterCriticalSection (&finalizer_mutex)
58 #define mono_finalizer_unlock() LeaveCriticalSection (&finalizer_mutex)
59 static CRITICAL_SECTION finalizer_mutex;
60 static CRITICAL_SECTION reference_queue_mutex;
62 static GSList *domains_to_finalize= NULL;
63 static MonoMList *threads_to_finalize = NULL;
65 static MonoInternalThread *gc_thread;
67 static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*));
69 static void mono_gchandle_set_target (guint32 gchandle, MonoObject *obj);
71 static void reference_queue_proccess_all (void);
72 static void mono_reference_queue_cleanup (void);
73 static void reference_queue_clear_for_domain (MonoDomain *domain);
75 static HANDLE pending_done_event;
76 static HANDLE shutdown_event;
80 add_thread_to_finalize (MonoInternalThread *thread)
82 mono_finalizer_lock ();
83 if (!threads_to_finalize)
84 MONO_GC_REGISTER_ROOT_SINGLE (threads_to_finalize);
85 threads_to_finalize = mono_mlist_append (threads_to_finalize, (MonoObject*)thread);
86 mono_finalizer_unlock ();
89 static gboolean suspend_finalizers = FALSE;
91 * actually, we might want to queue the finalize requests in a separate thread,
92 * but we need to be careful about the execution domain of the thread...
95 mono_gc_run_finalize (void *obj, void *data)
97 MonoObject *exc = NULL;
102 MonoMethod* finalizer = NULL;
103 MonoDomain *caller_domain = mono_domain_get ();
105 RuntimeInvokeFunction runtime_invoke;
106 GSList *l, *refs = NULL;
108 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
110 if (suspend_finalizers)
113 domain = o->vtable->domain;
116 mono_domain_finalizers_lock (domain);
118 o2 = g_hash_table_lookup (domain->finalizable_objects_hash, o);
120 refs = mono_gc_remove_weak_track_object (domain, o);
122 mono_domain_finalizers_unlock (domain);
125 /* Already finalized somehow */
131 * Support for GCHandles of type WeakTrackResurrection:
133 * Its not exactly clear how these are supposed to work, or how their
134 * semantics can be implemented. We only implement one crucial thing:
135 * these handles are only cleared after the finalizer has ran.
137 for (l = refs; l; l = l->next) {
138 guint32 gchandle = GPOINTER_TO_UINT (l->data);
140 mono_gchandle_set_target (gchandle, o);
146 /* make sure the finalizer is not called again if the object is resurrected */
147 object_register_finalizer (obj, NULL);
149 if (o->vtable->klass == mono_defaults.internal_thread_class) {
150 MonoInternalThread *t = (MonoInternalThread*)o;
152 if (mono_gc_is_finalizer_internal_thread (t))
153 /* Avoid finalizing ourselves */
156 if (t->threadpool_thread && finalizing_root_domain) {
157 /* Don't finalize threadpool threads when
158 shutting down - they're finalized when the
159 threadpool shuts down. */
160 add_thread_to_finalize (t);
165 if (o->vtable->klass->image == mono_defaults.corlib && !strcmp (o->vtable->klass->name, "DynamicMethod") && finalizing_root_domain) {
167 * These can't be finalized during unloading/shutdown, since that would
168 * free the native code which can still be referenced by other
170 * FIXME: This is not perfect, objects dying at the same time as
171 * dynamic methods can still reference them even when !shutdown.
176 if (mono_runtime_get_no_exec ())
179 /* speedup later... and use a timeout */
180 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
182 /* Use _internal here, since this thread can enter a doomed appdomain */
183 mono_domain_set_internal (mono_object_domain (o));
185 /* delegates that have a native function pointer allocated are
186 * registered for finalization, but they don't have a Finalize
187 * method, because in most cases it's not needed and it's just a waste.
189 if (o->vtable->klass->delegate) {
190 MonoDelegate* del = (MonoDelegate*)o;
191 if (del->delegate_trampoline)
192 mono_delegate_free_ftnptr ((MonoDelegate*)o);
193 mono_domain_set_internal (caller_domain);
197 finalizer = mono_class_get_finalizer (o->vtable->klass);
200 /* If object has a CCW but has no finalizer, it was only
201 * registered for finalization in order to free the CCW.
202 * Else it needs the regular finalizer run.
203 * FIXME: what to do about ressurection and suppression
204 * of finalizer on object with CCW.
206 if (mono_marshal_free_ccw (o) && !finalizer) {
207 mono_domain_set_internal (caller_domain);
213 * To avoid the locking plus the other overhead of mono_runtime_invoke (),
214 * create and precompile a wrapper which calls the finalize method using
217 if (!domain->finalize_runtime_invoke) {
218 MonoMethod *invoke = mono_marshal_get_runtime_invoke (mono_class_get_method_from_name_flags (mono_defaults.object_class, "Finalize", 0, 0), TRUE);
220 domain->finalize_runtime_invoke = mono_compile_method (invoke);
223 runtime_invoke = domain->finalize_runtime_invoke;
225 mono_runtime_class_init (o->vtable);
227 runtime_invoke (o, NULL, &exc, NULL);
230 mono_internal_thread_unhandled_exception (exc);
232 mono_domain_set_internal (caller_domain);
236 mono_gc_finalize_threadpool_threads (void)
238 while (threads_to_finalize) {
239 MonoInternalThread *thread = (MonoInternalThread*) mono_mlist_get_data (threads_to_finalize);
241 /* Force finalization of the thread. */
242 thread->threadpool_thread = FALSE;
243 mono_object_register_finalizer ((MonoObject*)thread);
245 mono_gc_run_finalize (thread, NULL);
247 threads_to_finalize = mono_mlist_next (threads_to_finalize);
252 mono_gc_out_of_memory (size_t size)
255 * we could allocate at program startup some memory that we could release
256 * back to the system at this point if we're really low on memory (ie, size is
257 * lower than the memory we set apart)
259 mono_raise_exception (mono_domain_get ()->out_of_memory_ex);
265 * Some of our objects may point to a different address than the address returned by GC_malloc()
266 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
267 * This also means that in the callback we need to adjust the pointer to get back the real
269 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
270 * since that, too, can cause the underlying pointer to be offset.
273 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
280 mono_raise_exception (mono_get_exception_argument_null ("obj"));
282 domain = obj->vtable->domain;
285 /* This assertion is not valid when GC_DEBUG is defined */
286 g_assert (GC_base (obj) == (char*)obj - offset);
289 if (mono_domain_is_unloading (domain) && (callback != NULL))
291 * Can't register finalizers in a dying appdomain, since they
292 * could be invoked after the appdomain has been unloaded.
296 mono_domain_finalizers_lock (domain);
299 g_hash_table_insert (domain->finalizable_objects_hash, obj, obj);
301 g_hash_table_remove (domain->finalizable_objects_hash, obj);
303 mono_domain_finalizers_unlock (domain);
305 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
306 #elif defined(HAVE_SGEN_GC)
308 mono_raise_exception (mono_get_exception_argument_null ("obj"));
311 * If we register finalizers for domains that are unloading we might
312 * end up running them while or after the domain is being cleared, so
313 * the objects will not be valid anymore.
315 if (!mono_domain_is_unloading (obj->vtable->domain))
316 mono_gc_register_for_finalization (obj, callback);
321 * mono_object_register_finalizer:
322 * @obj: object to register
324 * Records that object @obj has a finalizer, this will call the
325 * Finalize method when the garbage collector disposes the object.
329 mono_object_register_finalizer (MonoObject *obj)
331 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
332 object_register_finalizer (obj, mono_gc_run_finalize);
336 * mono_domain_finalize:
337 * @domain: the domain to finalize
338 * @timeout: msects to wait for the finalization to complete, -1 to wait indefinitely
340 * Request finalization of all finalizable objects inside @domain. Wait
341 * @timeout msecs for the finalization to complete.
343 * Returns: TRUE if succeeded, FALSE if there was a timeout
347 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
349 DomainFinalizationReq *req;
352 MonoInternalThread *thread = mono_thread_internal_current ();
354 if (mono_thread_internal_current () == gc_thread)
355 /* We are called from inside a finalizer, not much we can do here */
359 * No need to create another thread 'cause the finalizer thread
360 * is still working and will take care of running the finalizers
367 mono_gc_collect (mono_gc_max_generation ());
369 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
370 if (done_event == NULL) {
374 req = g_new0 (DomainFinalizationReq, 1);
375 req->domain = domain;
376 req->done_event = done_event;
378 if (domain == mono_get_root_domain ())
379 finalizing_root_domain = TRUE;
381 mono_finalizer_lock ();
383 domains_to_finalize = g_slist_append (domains_to_finalize, req);
385 mono_finalizer_unlock ();
387 /* Tell the finalizer thread to finalize this appdomain */
388 mono_gc_finalize_notify ();
394 res = WaitForSingleObjectEx (done_event, timeout, TRUE);
395 /* printf ("WAIT RES: %d.\n", res); */
397 if (res == WAIT_IO_COMPLETION) {
398 if ((thread->state & (ThreadState_StopRequested | ThreadState_SuspendRequested)) != 0)
400 } else if (res == WAIT_TIMEOUT) {
401 /* We leak the handle here */
408 CloseHandle (done_event);
410 if (domain == mono_get_root_domain ()) {
411 mono_thread_pool_cleanup ();
412 mono_gc_finalize_threadpool_threads ();
417 /* We don't support domain finalization without a GC */
423 ves_icall_System_GC_InternalCollect (int generation)
425 mono_gc_collect (generation);
429 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
434 mono_gc_collect (mono_gc_max_generation ());
435 return mono_gc_get_used_size ();
439 ves_icall_System_GC_KeepAlive (MonoObject *obj)
449 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
452 mono_raise_exception (mono_get_exception_argument_null ("obj"));
454 object_register_finalizer (obj, mono_gc_run_finalize);
458 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
461 mono_raise_exception (mono_get_exception_argument_null ("obj"));
463 /* delegates have no finalizers, but we register them to deal with the
464 * unmanaged->managed trampoline. We don't let the user suppress it
465 * otherwise we'd leak it.
467 if (obj->vtable->klass->delegate)
470 /* FIXME: Need to handle case where obj has COM Callable Wrapper
471 * generated for it that needs cleaned up, but user wants to suppress
472 * their derived object finalizer. */
474 object_register_finalizer (obj, NULL);
478 ves_icall_System_GC_WaitForPendingFinalizers (void)
481 if (!mono_gc_pending_finalizers ())
484 if (mono_thread_internal_current () == gc_thread)
485 /* Avoid deadlocks */
489 If the finalizer thread is not live, lets pretend no finalizers are pending since the current thread might
490 be the one responsible for starting it up.
492 if (gc_thread == NULL)
495 ResetEvent (pending_done_event);
496 mono_gc_finalize_notify ();
497 /* g_print ("Waiting for pending finalizers....\n"); */
498 WaitForSingleObjectEx (pending_done_event, INFINITE, TRUE);
499 /* g_print ("Done pending....\n"); */
504 ves_icall_System_GC_register_ephemeron_array (MonoObject *array)
507 if (!mono_gc_ephemeron_array_add (array))
508 mono_raise_exception (mono_object_domain (array)->out_of_memory_ex);
513 ves_icall_System_GC_get_ephemeron_tombstone (void)
515 return mono_domain_get ()->ephemeron_tombstone;
518 #define mono_allocator_lock() EnterCriticalSection (&allocator_section)
519 #define mono_allocator_unlock() LeaveCriticalSection (&allocator_section)
520 static CRITICAL_SECTION allocator_section;
521 static CRITICAL_SECTION handle_section;
530 static HandleType mono_gchandle_get_type (guint32 gchandle);
533 ves_icall_System_GCHandle_GetTarget (guint32 handle)
535 return mono_gchandle_get_target (handle);
539 * if type == -1, change the target of the handle, otherwise allocate a new handle.
542 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
545 mono_gchandle_set_target (handle, obj);
546 /* the handle doesn't change */
551 return mono_gchandle_new_weakref (obj, FALSE);
552 case HANDLE_WEAK_TRACK:
553 return mono_gchandle_new_weakref (obj, TRUE);
555 return mono_gchandle_new (obj, FALSE);
557 return mono_gchandle_new (obj, TRUE);
559 g_assert_not_reached ();
565 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
567 mono_gchandle_free (handle);
571 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
575 if (mono_gchandle_get_type (handle) != HANDLE_PINNED)
577 obj = mono_gchandle_get_target (handle);
579 MonoClass *klass = mono_object_class (obj);
580 if (klass == mono_defaults.string_class) {
581 return mono_string_chars ((MonoString*)obj);
582 } else if (klass->rank) {
583 return mono_array_addr ((MonoArray*)obj, char, 0);
585 /* the C# code will check and throw the exception */
586 /* FIXME: missing !klass->blittable test, see bug #61134 */
587 if ((klass->flags & TYPE_ATTRIBUTE_LAYOUT_MASK) == TYPE_ATTRIBUTE_AUTO_LAYOUT)
589 return (char*)obj + sizeof (MonoObject);
600 guint slot_hint : 24; /* starting slot for search */
601 /* 2^16 appdomains should be enough for everyone (though I know I'll regret this in 20 years) */
602 /* we alloc this only for weak refs, since we can get the domain directly in the other cases */
606 /* weak and weak-track arrays will be allocated in malloc memory
608 static HandleData gc_handles [] = {
609 {NULL, NULL, 0, HANDLE_WEAK, 0},
610 {NULL, NULL, 0, HANDLE_WEAK_TRACK, 0},
611 {NULL, NULL, 0, HANDLE_NORMAL, 0},
612 {NULL, NULL, 0, HANDLE_PINNED, 0}
615 #define lock_handles(handles) EnterCriticalSection (&handle_section)
616 #define unlock_handles(handles) LeaveCriticalSection (&handle_section)
619 find_first_unset (guint32 bitmap)
622 for (i = 0; i < 32; ++i) {
623 if (!(bitmap & (1 << i)))
630 alloc_handle (HandleData *handles, MonoObject *obj, gboolean track)
634 lock_handles (handles);
635 if (!handles->size) {
637 if (handles->type > HANDLE_WEAK_TRACK) {
638 handles->entries = mono_gc_alloc_fixed (sizeof (gpointer) * handles->size, mono_gc_make_root_descr_all_refs (handles->size));
640 handles->entries = g_malloc0 (sizeof (gpointer) * handles->size);
641 handles->domain_ids = g_malloc0 (sizeof (guint16) * handles->size);
643 handles->bitmap = g_malloc0 (handles->size / 8);
646 for (slot = handles->slot_hint; slot < handles->size / 32; ++slot) {
647 if (handles->bitmap [slot] != 0xffffffff) {
648 i = find_first_unset (handles->bitmap [slot]);
649 handles->slot_hint = slot;
653 if (i == -1 && handles->slot_hint != 0) {
654 for (slot = 0; slot < handles->slot_hint; ++slot) {
655 if (handles->bitmap [slot] != 0xffffffff) {
656 i = find_first_unset (handles->bitmap [slot]);
657 handles->slot_hint = slot;
664 guint32 new_size = handles->size * 2; /* always double: we memset to 0 based on this below */
666 /* resize and copy the bitmap */
667 new_bitmap = g_malloc0 (new_size / 8);
668 memcpy (new_bitmap, handles->bitmap, handles->size / 8);
669 g_free (handles->bitmap);
670 handles->bitmap = new_bitmap;
672 /* resize and copy the entries */
673 if (handles->type > HANDLE_WEAK_TRACK) {
676 entries = mono_gc_alloc_fixed (sizeof (gpointer) * new_size, mono_gc_make_root_descr_all_refs (new_size));
677 memcpy (entries, handles->entries, sizeof (gpointer) * handles->size);
679 mono_gc_free_fixed (handles->entries);
680 handles->entries = entries;
684 domain_ids = g_malloc0 (sizeof (guint16) * new_size);
685 entries = g_malloc (sizeof (gpointer) * new_size);
686 /* we disable GC because we could lose some disappearing link updates */
688 memcpy (entries, handles->entries, sizeof (gpointer) * handles->size);
689 memset (entries + handles->size, 0, sizeof (gpointer) * handles->size);
690 memcpy (domain_ids, handles->domain_ids, sizeof (guint16) * handles->size);
691 for (i = 0; i < handles->size; ++i) {
692 MonoObject *obj = mono_gc_weak_link_get (&(handles->entries [i]));
693 if (handles->entries [i])
694 mono_gc_weak_link_remove (&(handles->entries [i]));
695 /*g_print ("reg/unreg entry %d of type %d at %p to object %p (%p), was: %p\n", i, handles->type, &(entries [i]), obj, entries [i], handles->entries [i]);*/
697 mono_gc_weak_link_add (&(entries [i]), obj, track);
700 g_free (handles->entries);
701 g_free (handles->domain_ids);
702 handles->entries = entries;
703 handles->domain_ids = domain_ids;
707 /* set i and slot to the next free position */
709 slot = (handles->size + 1) / 32;
710 handles->slot_hint = handles->size + 1;
711 handles->size = new_size;
713 handles->bitmap [slot] |= 1 << i;
714 slot = slot * 32 + i;
715 handles->entries [slot] = obj;
716 if (handles->type <= HANDLE_WEAK_TRACK) {
717 /*FIXME, what to use when obj == null?*/
718 handles->domain_ids [slot] = (obj ? mono_object_get_domain (obj) : mono_domain_get ())->domain_id;
720 mono_gc_weak_link_add (&(handles->entries [slot]), obj, track);
723 mono_perfcounters->gc_num_handles++;
724 unlock_handles (handles);
725 /*g_print ("allocated entry %d of type %d to object %p (in slot: %p)\n", slot, handles->type, obj, handles->entries [slot]);*/
726 res = (slot << 3) | (handles->type + 1);
727 mono_profiler_gc_handle (MONO_PROFILER_GC_HANDLE_CREATED, handles->type, res, obj);
733 * @obj: managed object to get a handle for
734 * @pinned: whether the object should be pinned
736 * This returns a handle that wraps the object, this is used to keep a
737 * reference to a managed object from the unmanaged world and preventing the
738 * object from being disposed.
740 * If @pinned is false the address of the object can not be obtained, if it is
741 * true the address of the object can be obtained. This will also pin the
742 * object so it will not be possible by a moving garbage collector to move the
745 * Returns: a handle that can be used to access the object from
749 mono_gchandle_new (MonoObject *obj, gboolean pinned)
751 return alloc_handle (&gc_handles [pinned? HANDLE_PINNED: HANDLE_NORMAL], obj, FALSE);
755 * mono_gchandle_new_weakref:
756 * @obj: managed object to get a handle for
757 * @pinned: whether the object should be pinned
759 * This returns a weak handle that wraps the object, this is used to
760 * keep a reference to a managed object from the unmanaged world.
761 * Unlike the mono_gchandle_new the object can be reclaimed by the
762 * garbage collector. In this case the value of the GCHandle will be
765 * If @pinned is false the address of the object can not be obtained, if it is
766 * true the address of the object can be obtained. This will also pin the
767 * object so it will not be possible by a moving garbage collector to move the
770 * Returns: a handle that can be used to access the object from
774 mono_gchandle_new_weakref (MonoObject *obj, gboolean track_resurrection)
776 guint32 handle = alloc_handle (&gc_handles [track_resurrection? HANDLE_WEAK_TRACK: HANDLE_WEAK], obj, track_resurrection);
779 if (track_resurrection)
780 mono_gc_add_weak_track_handle (obj, handle);
787 mono_gchandle_get_type (guint32 gchandle)
789 guint type = (gchandle & 7) - 1;
795 * mono_gchandle_get_target:
796 * @gchandle: a GCHandle's handle.
798 * The handle was previously created by calling mono_gchandle_new or
799 * mono_gchandle_new_weakref.
801 * Returns a pointer to the MonoObject represented by the handle or
802 * NULL for a collected object if using a weakref handle.
805 mono_gchandle_get_target (guint32 gchandle)
807 guint slot = gchandle >> 3;
808 guint type = (gchandle & 7) - 1;
809 HandleData *handles = &gc_handles [type];
810 MonoObject *obj = NULL;
813 lock_handles (handles);
814 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
815 if (handles->type <= HANDLE_WEAK_TRACK) {
816 obj = mono_gc_weak_link_get (&handles->entries [slot]);
818 obj = handles->entries [slot];
821 /* print a warning? */
823 unlock_handles (handles);
824 /*g_print ("get target of entry %d of type %d: %p\n", slot, handles->type, obj);*/
829 mono_gchandle_set_target (guint32 gchandle, MonoObject *obj)
831 guint slot = gchandle >> 3;
832 guint type = (gchandle & 7) - 1;
833 HandleData *handles = &gc_handles [type];
834 MonoObject *old_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 old_obj = handles->entries [slot];
842 if (handles->entries [slot])
843 mono_gc_weak_link_remove (&handles->entries [slot]);
845 mono_gc_weak_link_add (&handles->entries [slot], obj, handles->type == HANDLE_WEAK_TRACK);
846 /*FIXME, what to use when obj == null?*/
847 handles->domain_ids [slot] = (obj ? mono_object_get_domain (obj) : mono_domain_get ())->domain_id;
849 handles->entries [slot] = obj;
852 /* print a warning? */
854 /*g_print ("changed entry %d of type %d to object %p (in slot: %p)\n", slot, handles->type, obj, handles->entries [slot]);*/
855 unlock_handles (handles);
858 if (type == HANDLE_WEAK_TRACK)
859 mono_gc_change_weak_track_handle (old_obj, obj, gchandle);
864 * mono_gchandle_is_in_domain:
865 * @gchandle: a GCHandle's handle.
866 * @domain: An application domain.
868 * Returns: true if the object wrapped by the @gchandle belongs to the specific @domain.
871 mono_gchandle_is_in_domain (guint32 gchandle, MonoDomain *domain)
873 guint slot = gchandle >> 3;
874 guint type = (gchandle & 7) - 1;
875 HandleData *handles = &gc_handles [type];
876 gboolean result = FALSE;
879 lock_handles (handles);
880 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
881 if (handles->type <= HANDLE_WEAK_TRACK) {
882 result = domain->domain_id == handles->domain_ids [slot];
885 obj = handles->entries [slot];
889 result = domain == mono_object_domain (obj);
892 /* print a warning? */
894 unlock_handles (handles);
899 * mono_gchandle_free:
900 * @gchandle: a GCHandle's handle.
902 * Frees the @gchandle handle. If there are no outstanding
903 * references, the garbage collector can reclaim the memory of the
907 mono_gchandle_free (guint32 gchandle)
909 guint slot = gchandle >> 3;
910 guint type = (gchandle & 7) - 1;
911 HandleData *handles = &gc_handles [type];
915 if (type == HANDLE_WEAK_TRACK)
916 mono_gc_remove_weak_track_handle (gchandle);
919 lock_handles (handles);
920 if (slot < handles->size && (handles->bitmap [slot / 32] & (1 << (slot % 32)))) {
921 if (handles->type <= HANDLE_WEAK_TRACK) {
922 if (handles->entries [slot])
923 mono_gc_weak_link_remove (&handles->entries [slot]);
925 handles->entries [slot] = NULL;
927 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
929 /* print a warning? */
931 mono_perfcounters->gc_num_handles--;
932 /*g_print ("freed entry %d of type %d\n", slot, handles->type);*/
933 unlock_handles (handles);
934 mono_profiler_gc_handle (MONO_PROFILER_GC_HANDLE_DESTROYED, handles->type, gchandle, NULL);
938 * mono_gchandle_free_domain:
939 * @domain: domain that is unloading
941 * Function used internally to cleanup any GC handle for objects belonging
942 * to the specified domain during appdomain unload.
945 mono_gchandle_free_domain (MonoDomain *domain)
949 for (type = 0; type < 3; ++type) {
951 HandleData *handles = &gc_handles [type];
952 lock_handles (handles);
953 for (slot = 0; slot < handles->size; ++slot) {
954 if (!(handles->bitmap [slot / 32] & (1 << (slot % 32))))
956 if (type <= HANDLE_WEAK_TRACK) {
957 if (domain->domain_id == handles->domain_ids [slot]) {
958 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
959 if (handles->entries [slot])
960 mono_gc_weak_link_remove (&handles->entries [slot]);
963 if (handles->entries [slot] && mono_object_domain (handles->entries [slot]) == domain) {
964 handles->bitmap [slot / 32] &= ~(1 << (slot % 32));
965 handles->entries [slot] = NULL;
969 unlock_handles (handles);
975 GCHandle_CheckCurrentDomain (guint32 gchandle)
977 return mono_gchandle_is_in_domain (gchandle, mono_domain_get ());
982 #ifdef MONO_HAS_SEMAPHORES
983 static MonoSemType finalizer_sem;
985 static HANDLE finalizer_event;
986 static volatile gboolean finished=FALSE;
989 mono_gc_finalize_notify (void)
992 g_message ( "%s: prodding finalizer", __func__);
995 #ifdef MONO_HAS_SEMAPHORES
996 MONO_SEM_POST (&finalizer_sem);
998 SetEvent (finalizer_event);
1002 #ifdef HAVE_BOEHM_GC
1005 collect_objects (gpointer key, gpointer value, gpointer user_data)
1007 GPtrArray *arr = (GPtrArray*)user_data;
1008 g_ptr_array_add (arr, key);
1014 * finalize_domain_objects:
1016 * Run the finalizers of all finalizable objects in req->domain.
1019 finalize_domain_objects (DomainFinalizationReq *req)
1021 MonoDomain *domain = req->domain;
1024 #define NUM_FOBJECTS 64
1025 MonoObject *to_finalize [NUM_FOBJECTS];
1029 /* Process finalizers which are already in the queue */
1030 mono_gc_invoke_finalizers ();
1032 #ifdef HAVE_BOEHM_GC
1033 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
1037 * Since the domain is unloading, nobody is allowed to put
1038 * new entries into the hash table. But finalize_object might
1039 * remove entries from the hash table, so we make a copy.
1041 objs = g_ptr_array_new ();
1042 g_hash_table_foreach (domain->finalizable_objects_hash, collect_objects, objs);
1043 /* printf ("FINALIZING %d OBJECTS.\n", objs->len); */
1045 for (i = 0; i < objs->len; ++i) {
1046 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
1047 /* FIXME: Avoid finalizing threads, etc */
1048 mono_gc_run_finalize (o, 0);
1051 g_ptr_array_free (objs, TRUE);
1053 #elif defined(HAVE_SGEN_GC)
1054 while ((count = mono_gc_finalizers_for_domain (domain, to_finalize, NUM_FOBJECTS))) {
1056 for (i = 0; i < count; ++i) {
1057 mono_gc_run_finalize (to_finalize [i], 0);
1062 /* cleanup the reference queue */
1063 reference_queue_clear_for_domain (domain);
1065 /* printf ("DONE.\n"); */
1066 SetEvent (req->done_event);
1068 /* The event is closed in mono_domain_finalize if we get here */
1073 finalizer_thread (gpointer unused)
1076 /* Wait to be notified that there's at least one
1080 g_assert (mono_domain_get () == mono_get_root_domain ());
1082 /* An alertable wait is required so this thread can be suspended on windows */
1083 #ifdef MONO_HAS_SEMAPHORES
1084 MONO_SEM_WAIT_ALERTABLE (&finalizer_sem, TRUE);
1086 WaitForSingleObjectEx (finalizer_event, INFINITE, TRUE);
1089 mono_threads_perform_thread_dump ();
1091 mono_console_handle_async_ops ();
1093 #ifndef DISABLE_ATTACH
1094 mono_attach_maybe_start ();
1097 if (domains_to_finalize) {
1098 mono_finalizer_lock ();
1099 if (domains_to_finalize) {
1100 DomainFinalizationReq *req = domains_to_finalize->data;
1101 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
1102 mono_finalizer_unlock ();
1104 finalize_domain_objects (req);
1106 mono_finalizer_unlock ();
1110 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
1111 * before the domain is unloaded.
1113 mono_gc_invoke_finalizers ();
1115 reference_queue_proccess_all ();
1117 SetEvent (pending_done_event);
1120 SetEvent (shutdown_event);
1127 InitializeCriticalSection (&handle_section);
1128 InitializeCriticalSection (&allocator_section);
1130 InitializeCriticalSection (&finalizer_mutex);
1131 InitializeCriticalSection (&reference_queue_mutex);
1133 MONO_GC_REGISTER_ROOT_FIXED (gc_handles [HANDLE_NORMAL].entries);
1134 MONO_GC_REGISTER_ROOT_FIXED (gc_handles [HANDLE_PINNED].entries);
1136 mono_gc_base_init ();
1138 if (mono_gc_is_disabled ()) {
1143 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
1144 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
1145 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
1146 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL) {
1147 g_assert_not_reached ();
1149 #ifdef MONO_HAS_SEMAPHORES
1150 MONO_SEM_INIT (&finalizer_sem, 0);
1153 gc_thread = mono_thread_create_internal (mono_domain_get (), finalizer_thread, NULL, FALSE, 0);
1154 ves_icall_System_Threading_Thread_SetName_internal (gc_thread, mono_string_new (mono_domain_get (), "Finalizer"));
1158 mono_gc_cleanup (void)
1161 g_message ("%s: cleaning up finalizer", __func__);
1165 ResetEvent (shutdown_event);
1167 if (mono_thread_internal_current () != gc_thread) {
1168 mono_gc_finalize_notify ();
1169 /* Finishing the finalizer thread, so wait a little bit... */
1170 /* MS seems to wait for about 2 seconds */
1171 if (WaitForSingleObjectEx (shutdown_event, 2000, FALSE) == WAIT_TIMEOUT) {
1174 /* Set a flag which the finalizer thread can check */
1175 suspend_finalizers = TRUE;
1177 /* Try to abort the thread, in the hope that it is running managed code */
1178 mono_thread_internal_stop (gc_thread);
1180 /* Wait for it to stop */
1181 ret = WaitForSingleObjectEx (gc_thread->handle, 100, TRUE);
1183 if (ret == WAIT_TIMEOUT) {
1185 * The finalizer thread refused to die. There is not much we
1186 * can do here, since the runtime is shutting down so the
1187 * state the finalizer thread depends on will vanish.
1189 g_warning ("Shutting down finalizer thread timed out.");
1192 * FIXME: On unix, when the above wait returns, the thread
1193 * might still be running io-layer code, or pthreads code.
1201 #ifdef HAVE_BOEHM_GC
1202 GC_finalizer_notifier = NULL;
1206 mono_reference_queue_cleanup ();
1208 DeleteCriticalSection (&handle_section);
1209 DeleteCriticalSection (&allocator_section);
1210 DeleteCriticalSection (&finalizer_mutex);
1211 DeleteCriticalSection (&reference_queue_mutex);
1216 /* Null GC dummy functions */
1218 mono_gc_finalize_notify (void)
1222 void mono_gc_init (void)
1224 InitializeCriticalSection (&handle_section);
1227 void mono_gc_cleanup (void)
1234 mono_gc_is_finalizer_internal_thread (MonoInternalThread *thread)
1236 return thread == gc_thread;
1240 * mono_gc_is_finalizer_thread:
1241 * @thread: the thread to test.
1243 * In Mono objects are finalized asynchronously on a separate thread.
1244 * This routine tests whether the @thread argument represents the
1245 * finalization thread.
1247 * Returns true if @thread is the finalization thread.
1250 mono_gc_is_finalizer_thread (MonoThread *thread)
1252 return mono_gc_is_finalizer_internal_thread (thread->internal_thread);
1255 #if defined(__MACH__)
1256 static pthread_t mach_exception_thread;
1259 mono_gc_register_mach_exception_thread (pthread_t thread)
1261 mach_exception_thread = thread;
1265 mono_gc_get_mach_exception_thread (void)
1267 return mach_exception_thread;
1272 * mono_gc_parse_environment_string_extract_number:
1274 * @str: points to the first digit of the number
1275 * @out: pointer to the variable that will receive the value
1277 * Tries to extract a number from the passed string, taking in to account m, k
1280 * Returns true if passing was successful
1283 mono_gc_parse_environment_string_extract_number (const char *str, glong *out)
1286 int len = strlen (str), shift = 0;
1288 gboolean is_suffix = FALSE;
1294 suffix = str [len - 1];
1309 if (!isdigit (suffix))
1315 val = strtol (str, &endptr, 10);
1317 if ((errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
1318 || (errno != 0 && val == 0) || (endptr == str))
1322 if (*(endptr + 1)) /* Invalid string. */
1331 #ifndef HAVE_SGEN_GC
1333 mono_gc_alloc_mature (MonoVTable *vtable)
1335 return mono_object_new_specific (vtable);
1340 static MonoReferenceQueue *ref_queues;
1343 ref_list_remove_element (RefQueueEntry **prev, RefQueueEntry *element)
1346 /* Guard if head is changed concurrently. */
1347 while (*prev != element)
1348 prev = &(*prev)->next;
1349 } while (prev && InterlockedCompareExchangePointer ((void*)prev, element->next, element) != element);
1353 ref_list_push (RefQueueEntry **head, RefQueueEntry *value)
1355 RefQueueEntry *current;
1358 value->next = current;
1359 STORE_STORE_FENCE; /*Must make sure the previous store is visible before the CAS. */
1360 } while (InterlockedCompareExchangePointer ((void*)head, value, current) != current);
1364 reference_queue_proccess (MonoReferenceQueue *queue)
1366 RefQueueEntry **iter = &queue->queue;
1367 RefQueueEntry *entry;
1368 while ((entry = *iter)) {
1370 if (queue->should_be_deleted || !mono_gc_weak_link_get (&entry->dis_link)) {
1371 mono_gc_weak_link_remove (&entry->dis_link);
1373 if (queue->should_be_deleted || !mono_gchandle_get_target (entry->gchandle)) {
1374 mono_gchandle_free ((guint32)entry->gchandle);
1376 ref_list_remove_element (iter, entry);
1377 queue->callback (entry->user_data);
1380 iter = &entry->next;
1386 reference_queue_proccess_all (void)
1388 MonoReferenceQueue **iter;
1389 MonoReferenceQueue *queue = ref_queues;
1390 for (; queue; queue = queue->next)
1391 reference_queue_proccess (queue);
1394 EnterCriticalSection (&reference_queue_mutex);
1395 for (iter = &ref_queues; *iter;) {
1397 if (!queue->should_be_deleted) {
1398 iter = &queue->next;
1402 LeaveCriticalSection (&reference_queue_mutex);
1403 reference_queue_proccess (queue);
1406 *iter = queue->next;
1409 LeaveCriticalSection (&reference_queue_mutex);
1413 mono_reference_queue_cleanup (void)
1415 MonoReferenceQueue *queue = ref_queues;
1416 for (; queue; queue = queue->next)
1417 queue->should_be_deleted = TRUE;
1418 reference_queue_proccess_all ();
1422 reference_queue_clear_for_domain (MonoDomain *domain)
1424 MonoReferenceQueue *queue = ref_queues;
1425 for (; queue; queue = queue->next) {
1426 RefQueueEntry **iter = &queue->queue;
1427 RefQueueEntry *entry;
1428 while ((entry = *iter)) {
1431 obj = mono_gc_weak_link_get (&entry->dis_link);
1432 if (obj && mono_object_domain (obj) == domain) {
1433 mono_gc_weak_link_remove (&entry->dis_link);
1435 obj = mono_gchandle_get_target (entry->gchandle);
1436 if (obj && mono_object_domain (obj) == domain) {
1437 mono_gchandle_free ((guint32)entry->gchandle);
1439 ref_list_remove_element (iter, entry);
1440 queue->callback (entry->user_data);
1443 iter = &entry->next;
1449 * mono_gc_reference_queue_new:
1450 * @callback callback used when processing dead entries.
1452 * Create a new reference queue used to process collected objects.
1453 * A reference queue let you queue a pair (managed object, user data)
1454 * using the mono_gc_reference_queue_add method.
1456 * Once the managed object is collected @callback will be called
1457 * in the finalizer thread with 'user data' as argument.
1459 * The callback is called without any locks held.
1462 mono_gc_reference_queue_new (mono_reference_queue_callback callback)
1464 MonoReferenceQueue *res = g_new0 (MonoReferenceQueue, 1);
1465 res->callback = callback;
1467 EnterCriticalSection (&reference_queue_mutex);
1468 res->next = ref_queues;
1470 LeaveCriticalSection (&reference_queue_mutex);
1476 * mono_gc_reference_queue_add:
1477 * @queue the queue to add the reference to.
1478 * @obj the object to be watched for collection
1479 * @user_data parameter to be passed to the queue callback
1481 * Queue an object to be watched for collection, when the @obj is
1482 * collected, the callback that was registered for the @queue will
1483 * be invoked with the @obj and @user_data arguments.
1485 * @returns false if the queue is scheduled to be freed.
1488 mono_gc_reference_queue_add (MonoReferenceQueue *queue, MonoObject *obj, void *user_data)
1490 RefQueueEntry *entry;
1491 if (queue->should_be_deleted)
1494 entry = g_new0 (RefQueueEntry, 1);
1495 entry->user_data = user_data;
1498 mono_gc_weak_link_add (&entry->dis_link, obj, TRUE);
1500 entry->gchandle = mono_gchandle_new_weakref (obj, TRUE);
1501 mono_object_register_finalizer (obj);
1504 ref_list_push (&queue->queue, entry);
1509 * mono_gc_reference_queue_free:
1510 * @queue the queue that should be deleted.
1512 * This operation signals that @queue should be deleted. This operation is deferred
1513 * as it happens on the finalizer thread.
1515 * After this call, no further objects can be queued. It's the responsibility of the
1516 * caller to make sure that no further attempt to access queue will be made.
1519 mono_gc_reference_queue_free (MonoReferenceQueue *queue)
1521 queue->should_be_deleted = TRUE;
1524 #define ptr_mask ((sizeof (void*) - 1))
1525 #define _toi(ptr) ((size_t)ptr)
1526 #define unaligned_bytes(ptr) (_toi(ptr) & ptr_mask)
1527 #define align_down(ptr) ((void*)(_toi(ptr) & ~ptr_mask))
1528 #define align_up(ptr) ((void*) ((_toi(ptr) + ptr_mask) & ~ptr_mask))
1532 * @dest: address to start to clear
1533 * @size: size of the region to clear
1535 * Zero @size bytes starting at @dest.
1537 * Use this to zero memory that can hold managed pointers.
1539 * FIXME borrow faster code from some BSD libc or bionic
1542 mono_gc_bzero (void *dest, size_t size)
1544 char *p = (char*)dest;
1545 char *end = p + size;
1546 char *align_end = align_up (p);
1549 while (p < align_end)
1552 word_end = align_down (end);
1553 while (p < word_end) {
1554 *((void**)p) = NULL;
1555 p += sizeof (void*);
1565 * @dest: destination of the move
1567 * @size: size of the block to move
1569 * Move @size bytes from @src to @dest.
1570 * size MUST be a multiple of sizeof (gpointer)
1572 * FIXME borrow faster code from some BSD libc or bionic
1575 mono_gc_memmove (void *dest, const void *src, size_t size)
1578 * If dest and src are differently aligned with respect to
1579 * pointer size then it makes no sense to do aligned copying.
1580 * In fact, we would end up with unaligned loads which is
1581 * incorrect on some architectures.
1583 if ((char*)dest - (char*)align_down (dest) != (char*)src - (char*)align_down (src)) {
1584 memmove (dest, src, size);
1589 * A bit of explanation on why we align only dest before doing word copies.
1590 * Pointers to managed objects must always be stored in word aligned addresses, so
1591 * even if dest is misaligned, src will be by the same amount - this ensure proper atomicity of reads.
1593 if (dest > src && ((size_t)((char*)dest - (char*)src) < size)) {
1594 char *p = (char*)dest + size;
1595 char *s = (char*)src + size;
1596 char *start = (char*)dest;
1597 char *align_end = MAX((char*)dest, (char*)align_down (p));
1600 while (p > align_end)
1603 word_start = align_up (start);
1604 while (p > word_start) {
1605 p -= sizeof (void*);
1606 s -= sizeof (void*);
1607 *((void**)p) = *((void**)s);
1613 char *p = (char*)dest;
1614 char *s = (char*)src;
1615 char *end = p + size;
1616 char *align_end = MIN ((char*)end, (char*)align_up (p));
1619 while (p < align_end)
1622 word_end = align_down (end);
1623 while (p < word_end) {
1624 *((void**)p) = *((void**)s);
1625 p += sizeof (void*);
1626 s += sizeof (void*);