2 * metadata/gc.c: GC icalls.
4 * Author: Paolo Molaro <lupus@ximian.com>
6 * (C) 2002 Ximian, Inc.
13 #include <mono/metadata/gc-internal.h>
14 #include <mono/metadata/threads.h>
15 #include <mono/metadata/tabledefs.h>
16 #include <mono/metadata/exception.h>
17 #define GC_I_HIDE_POINTERS
18 #include <mono/os/gc_wrapper.h>
21 #define HIDE_POINTER(v) (v)
22 #define REVEAL_POINTER(v) (v)
25 typedef struct DomainFinalizationReq {
28 } DomainFinalizationReq;
30 #ifdef PLATFORM_WINCE /* FIXME: add accessors to gc.dll API */
31 extern void (*__imp_GC_finalizer_notifier)(void);
32 #define GC_finalizer_notifier __imp_GC_finalizer_notifier
33 extern int __imp_GC_finalize_on_demand;
34 #define GC_finalize_on_demand __imp_GC_finalize_on_demand
37 static int finalize_slot = -1;
39 static gboolean gc_disabled = FALSE;
41 static CRITICAL_SECTION finalizer_mutex;
43 static GSList *domains_to_finalize= NULL;
45 static MonoThread *gc_thread;
47 static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*));
50 static void finalize_notify (void);
51 static HANDLE pending_done_event;
52 static HANDLE shutdown_event;
53 static HANDLE thread_started_event;
57 * actually, we might want to queue the finalize requests in a separate thread,
58 * but we need to be careful about the execution domain of the thread...
61 run_finalize (void *obj, void *data)
63 MonoObject *exc = NULL;
65 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
67 if (finalize_slot < 0) {
69 for (i = 0; i < mono_defaults.object_class->vtable_size; ++i) {
70 MonoMethod *cm = mono_defaults.object_class->vtable [i];
72 if (!strcmp (cm->name, "Finalize")) {
79 mono_domain_lock (o->vtable->domain);
81 o2 = g_hash_table_lookup (o->vtable->domain->finalizable_objects_hash, o);
83 mono_domain_unlock (o->vtable->domain);
86 /* Already finalized somehow */
89 /* make sure the finalizer is not called again if the object is resurrected */
90 object_register_finalizer (obj, NULL);
92 if (o->vtable->klass == mono_defaults.thread_class)
93 if (mono_gc_is_finalizer_thread ((MonoThread*)o))
94 /* Avoid finalizing ourselves */
97 /* speedup later... and use a timeout */
98 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
100 /* Use _internal here, since this thread can enter a doomed appdomain */
101 mono_domain_set_internal (mono_object_domain (o));
103 mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
106 /* fixme: do something useful */
111 * Some of our objects may point to a different address than the address returned by GC_malloc()
112 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
113 * This also means that in the callback we need to adjust the pointer to get back the real
115 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
116 * since that, too, can cause the underlying pointer to be offset.
119 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
125 /* This assertion is not valid when GC_DEBUG is defined */
126 g_assert (GC_base (obj) == (char*)obj - offset);
129 if (mono_domain_is_unloading (obj->vtable->domain) && (callback != NULL))
131 * Can't register finalizers in a dying appdomain, since they
132 * could be invoked after the appdomain has been unloaded.
136 mono_domain_lock (obj->vtable->domain);
139 g_hash_table_insert (obj->vtable->domain->finalizable_objects_hash, obj,
142 g_hash_table_remove (obj->vtable->domain->finalizable_objects_hash, obj);
144 mono_domain_unlock (obj->vtable->domain);
146 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
151 mono_object_register_finalizer (MonoObject *obj)
153 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
154 object_register_finalizer (obj, run_finalize);
158 * mono_domain_finalize:
160 * Request finalization of all finalizable objects inside @domain. Wait
161 * @timeout msecs for the finalization to complete.
162 * Returns: TRUE if succeeded, FALSE if there was a timeout
166 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
168 DomainFinalizationReq *req;
173 * No need to create another thread 'cause the finalizer thread
174 * is still working and will take care of running the finalizers
183 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
185 req = g_new0 (DomainFinalizationReq, 1);
186 req->domain = domain;
187 req->done_event = done_event;
189 EnterCriticalSection (&finalizer_mutex);
191 domains_to_finalize = g_slist_append (domains_to_finalize, req);
193 LeaveCriticalSection (&finalizer_mutex);
195 /* Tell the finalizer thread to finalize this appdomain */
198 res = WaitForSingleObject (done_event, timeout);
200 /* printf ("WAIT RES: %d.\n", res); */
201 if (res == WAIT_TIMEOUT) {
202 /* We leak the handle here */
206 CloseHandle (done_event);
209 /* We don't support domain finalization without a GC */
215 ves_icall_System_GC_InternalCollect (int generation)
225 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
232 return GC_get_heap_size () - GC_get_free_bytes ();
239 ves_icall_System_GC_KeepAlive (MonoObject *obj)
249 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
253 object_register_finalizer (obj, run_finalize);
257 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
261 object_register_finalizer (obj, NULL);
265 ves_icall_System_GC_WaitForPendingFinalizers (void)
270 if (!GC_should_invoke_finalizers ())
273 if (mono_thread_current () == gc_thread)
274 /* Avoid deadlocks */
277 ResetEvent (pending_done_event);
279 /* g_print ("Waiting for pending finalizers....\n"); */
280 WaitForSingleObject (pending_done_event, INFINITE);
281 /* g_print ("Done pending....\n"); */
286 static CRITICAL_SECTION allocator_section;
287 static CRITICAL_SECTION handle_section;
288 static guint32 next_handle = 0;
289 static gpointer *gc_handles = NULL;
290 static guint8 *gc_handle_types = NULL;
291 static guint32 array_size = 0;
294 * The handle type is encoded in the lower two bits of the handle value:
308 * FIXME: make thread safe and reuse the array entries.
311 ves_icall_System_GCHandle_GetTarget (guint32 handle)
320 EnterCriticalSection (&handle_section);
321 g_assert (type == gc_handle_types [handle >> 2]);
322 obj = gc_handles [handle >> 2];
323 LeaveCriticalSection (&handle_section);
327 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
328 return REVEAL_POINTER (obj);
336 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
343 EnterCriticalSection (&handle_section);
344 /* Indexes start from 1 since 0 means the handle is not allocated */
346 if (idx >= array_size) {
349 guint8 *new_type_array;
352 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
353 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
356 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
357 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
358 /* need to re-register links for weak refs. test if GC_realloc needs the same */
359 for (i = 0; i < array_size; ++i) {
360 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
361 * inside libgc. I assume it will also break without the
362 * threaded finalizer, just that the stress test (bug 31333)
363 * deadlocks too early without it. Reverting to the previous
364 * version here stops the segfault.
366 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
368 if (((gulong)new_array [i]) & 0x1) {
370 if (gc_handles [i] != (gpointer)-1)
371 GC_unregister_disappearing_link (&(gc_handles [i]));
372 if (new_array [i] != (gpointer)-1)
373 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
378 gc_handles = new_array;
379 gc_handle_types = new_type_array;
381 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
385 /* resuse the type from the old target */
388 h = (idx << 2) | type;
391 case HANDLE_WEAK_TRACK:
392 val = (gpointer)HIDE_POINTER (val);
393 gc_handles [idx] = val;
394 gc_handle_types [idx] = type;
396 if (gc_handles [idx] != (gpointer)-1)
397 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
399 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
403 gc_handles [idx] = val;
404 gc_handle_types [idx] = type;
407 LeaveCriticalSection (&handle_section);
412 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
414 int idx = handle >> 2;
415 int type = handle & 0x3;
419 EnterCriticalSection (&handle_section);
422 g_assert (type == gc_handle_types [idx]);
423 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
424 if (gc_handles [idx] != (gpointer)-1)
425 GC_unregister_disappearing_link (&(gc_handles [idx]));
428 LeaveCriticalSection (&handle_section);
429 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
432 gc_handles [idx] = (gpointer)-1;
433 gc_handle_types [idx] = (guint8)-1;
434 LeaveCriticalSection (&handle_section);
438 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
441 int type = handle & 0x3;
446 EnterCriticalSection (&handle_section);
447 obj = gc_handles [handle >> 2];
448 g_assert (gc_handle_types [handle >> 2] == type);
449 LeaveCriticalSection (&handle_section);
450 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
451 obj = REVEAL_POINTER (obj);
452 if (obj == (MonoObject *) -1)
462 static HANDLE finalizer_event;
463 static volatile gboolean finished=FALSE;
465 static void finalize_notify (void)
468 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
471 SetEvent (finalizer_event);
475 collect_objects (gpointer key, gpointer value, gpointer user_data)
477 GPtrArray *arr = (GPtrArray*)user_data;
478 g_ptr_array_add (arr, key);
482 * finalize_domain_objects:
484 * Run the finalizers of all finalizable objects in req->domain.
487 finalize_domain_objects (DomainFinalizationReq *req)
491 MonoDomain *domain = req->domain;
493 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
495 * Since the domain is unloading, nobody is allowed to put
496 * new entries into the hash table. But finalize_object might
497 * remove entries from the hash table, so we make a copy.
499 objs = g_ptr_array_new ();
500 g_hash_table_foreach (domain->finalizable_objects_hash,
501 collect_objects, objs);
502 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
504 for (i = 0; i < objs->len; ++i) {
505 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
506 /* FIXME: Avoid finalizing threads, etc */
510 g_ptr_array_free (objs, TRUE);
513 /* printf ("DONE.\n"); */
514 SetEvent (req->done_event);
516 /* The event is closed in mono_domain_finalize if we get here */
520 static guint32 finalizer_thread (gpointer unused)
522 gc_thread = mono_thread_current ();
524 SetEvent (thread_started_event);
527 /* Wait to be notified that there's at least one
530 WaitForSingleObject (finalizer_event, INFINITE);
532 if (domains_to_finalize) {
533 EnterCriticalSection (&finalizer_mutex);
534 if (domains_to_finalize) {
535 DomainFinalizationReq *req = domains_to_finalize->data;
536 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
537 LeaveCriticalSection (&finalizer_mutex);
539 finalize_domain_objects (req);
542 LeaveCriticalSection (&finalizer_mutex);
546 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
549 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
550 * before the domain is unloaded.
552 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
553 * the 'mem_freed' variable is not initialized when there are no
554 * objects to finalize, which leads to strange behavior later on.
555 * The check is necessary to work around that bug.
557 if (GC_should_invoke_finalizers ()) {
558 GC_invoke_finalizers ();
561 SetEvent (pending_done_event);
564 SetEvent (shutdown_event);
570 * Enable or disable the separate finalizer thread.
571 * It's currently disabled because it still requires some
572 * work in the rest of the runtime.
574 #define ENABLE_FINALIZER_THREAD
576 #ifdef WITH_INCLUDED_LIBGC
578 extern void mono_gc_stop_world (void);
579 extern void mono_gc_start_world (void);
580 extern void mono_gc_push_all_stacks (void);
582 static void mono_gc_lock (void)
584 EnterCriticalSection (&allocator_section);
587 static void mono_gc_unlock (void)
589 LeaveCriticalSection (&allocator_section);
592 static GCThreadFunctions mono_gc_thread_vtable = {
600 mono_gc_push_all_stacks,
603 #endif /* WITH_INCLUDED_LIBGC */
605 void mono_gc_init (void)
607 InitializeCriticalSection (&handle_section);
608 InitializeCriticalSection (&allocator_section);
610 InitializeCriticalSection (&finalizer_mutex);
612 #ifdef WITH_INCLUDED_LIBGC
613 gc_thread_vtable = &mono_gc_thread_vtable;
616 #ifdef ENABLE_FINALIZER_THREAD
618 if (getenv ("GC_DONT_GC")) {
623 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
624 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
625 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
626 thread_started_event = CreateEvent (NULL, TRUE, FALSE, NULL);
627 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL || thread_started_event == NULL) {
628 g_assert_not_reached ();
631 GC_finalize_on_demand = 1;
632 GC_finalizer_notifier = finalize_notify;
634 mono_thread_create (mono_domain_get (), finalizer_thread, NULL);
636 * Wait until the finalizer thread sets gc_thread since its value is needed
637 * by mono_thread_attach ()
639 WaitForSingleObject (thread_started_event, INFINITE);
643 void mono_gc_cleanup (void)
646 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
649 #ifdef ENABLE_FINALIZER_THREAD
651 ResetEvent (shutdown_event);
654 /* Finishing the finalizer thread, so wait a little bit... */
655 /* MS seems to wait for about 2 seconds */
657 * FIXME: This is not thread safe. If the finalizer thread keeps
658 * running, and the runtime is shut down, it will lead to a crash.
660 WaitForSingleObject (shutdown_event, 2000);
667 mono_gc_disable (void)
669 #ifdef HAVE_GC_ENABLE
672 g_assert_not_reached ();
677 mono_gc_enable (void)
679 #ifdef HAVE_GC_ENABLE
682 g_assert_not_reached ();
688 /* no Boehm GC support. */
689 void mono_gc_init (void)
691 InitializeCriticalSection (&handle_section);
694 void mono_gc_cleanup (void)
699 mono_gc_disable (void)
704 mono_gc_enable (void)
711 mono_gc_is_finalizer_thread (MonoThread *thread)
713 return thread == gc_thread;