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 HANDLE 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;
56 * actually, we might want to queue the finalize requests in a separate thread,
57 * but we need to be careful about the execution domain of the thread...
60 run_finalize (void *obj, void *data)
62 MonoObject *exc = NULL;
64 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
66 if (finalize_slot < 0) {
68 for (i = 0; i < mono_defaults.object_class->vtable_size; ++i) {
69 MonoMethod *cm = mono_defaults.object_class->vtable [i];
71 if (!strcmp (cm->name, "Finalize")) {
78 mono_domain_lock (o->vtable->domain);
80 o2 = g_hash_table_lookup (o->vtable->domain->finalizable_objects_hash, o);
82 mono_domain_unlock (o->vtable->domain);
85 /* Already finalized somehow */
88 /* make sure the finalizer is not called again if the object is resurrected */
89 object_register_finalizer (obj, NULL);
90 /* speedup later... and use a timeout */
91 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
93 /* Use _internal here, since this thread can enter a doomed appdomain */
94 mono_domain_set_internal (mono_object_domain (o));
96 mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
99 /* fixme: do something useful */
104 * Some of our objects may point to a different address than the address returned by GC_malloc()
105 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
106 * This also means that in the callback we need to adjust the pointer to get back the real
108 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
109 * since that, too, can cause the underlying pointer to be offset.
112 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
118 /* This assertion is not valid when GC_DEBUG is defined */
119 g_assert (GC_base (obj) == (char*)obj - offset);
122 if (mono_domain_is_unloading (obj->vtable->domain) && (callback != NULL))
124 * Can't register finalizers in a dying appdomain, since they
125 * could be invoked after the appdomain has been unloaded.
129 mono_domain_lock (obj->vtable->domain);
132 g_hash_table_insert (obj->vtable->domain->finalizable_objects_hash, obj,
135 g_hash_table_remove (obj->vtable->domain->finalizable_objects_hash, obj);
137 mono_domain_unlock (obj->vtable->domain);
139 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
144 mono_object_register_finalizer (MonoObject *obj)
146 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
147 object_register_finalizer (obj, run_finalize);
151 * mono_domain_finalize:
153 * Request finalization of all finalizable objects inside @domain. Wait
154 * @timeout msecs for the finalization to complete.
155 * Returns: TRUE if succeeded, FALSE if there was a timeout
159 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
161 DomainFinalizationReq *req;
166 * No need to create another thread 'cause the finalizer thread
167 * is still working and will take care of running the finalizers
176 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
178 req = g_new0 (DomainFinalizationReq, 1);
179 req->domain = domain;
180 req->done_event = done_event;
182 EnterCriticalSection (&finalizer_mutex);
184 domains_to_finalize = g_slist_append (domains_to_finalize, req);
186 LeaveCriticalSection (&finalizer_mutex);
188 /* Tell the finalizer thread to finalize this appdomain */
191 res = WaitForSingleObject (done_event, timeout);
193 //printf ("WAIT RES: %d.\n", res);
194 if (res == WAIT_TIMEOUT)
199 /* We don't support domain finalization without a GC */
205 ves_icall_System_GC_InternalCollect (int generation)
215 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
222 return GC_get_heap_size () - GC_get_free_bytes ();
229 ves_icall_System_GC_KeepAlive (MonoObject *obj)
239 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
243 object_register_finalizer (obj, run_finalize);
247 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
251 object_register_finalizer (obj, NULL);
255 ves_icall_System_GC_WaitForPendingFinalizers (void)
260 if (!GC_should_invoke_finalizers ())
263 if (GetCurrentThread () == gc_thread)
264 /* Avoid deadlocks */
267 ResetEvent (pending_done_event);
269 /* g_print ("Waiting for pending finalizers....\n"); */
270 WaitForSingleObject (pending_done_event, INFINITE);
271 /* g_print ("Done pending....\n"); */
276 static CRITICAL_SECTION allocator_section;
277 static CRITICAL_SECTION handle_section;
278 static guint32 next_handle = 0;
279 static gpointer *gc_handles = NULL;
280 static guint8 *gc_handle_types = NULL;
281 static guint32 array_size = 0;
284 * The handle type is encoded in the lower two bits of the handle value:
298 * FIXME: make thread safe and reuse the array entries.
301 ves_icall_System_GCHandle_GetTarget (guint32 handle)
310 EnterCriticalSection (&handle_section);
311 g_assert (type == gc_handle_types [handle >> 2]);
312 obj = gc_handles [handle >> 2];
313 LeaveCriticalSection (&handle_section);
317 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
318 return REVEAL_POINTER (obj);
326 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
333 EnterCriticalSection (&handle_section);
334 /* Indexes start from 1 since 0 means the handle is not allocated */
336 if (idx >= array_size) {
339 guint8 *new_type_array;
342 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
343 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
346 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
347 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
348 /* need to re-register links for weak refs. test if GC_realloc needs the same */
349 for (i = 0; i < array_size; ++i) {
350 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
351 * inside libgc. I assume it will also break without the
352 * threaded finalizer, just that the stress test (bug 31333)
353 * deadlocks too early without it. Reverting to the previous
354 * version here stops the segfault.
356 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
358 if (((gulong)new_array [i]) & 0x1) {
360 if (gc_handles [i] != (gpointer)-1)
361 GC_unregister_disappearing_link (&(gc_handles [i]));
362 if (new_array [i] != (gpointer)-1)
363 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
368 gc_handles = new_array;
369 gc_handle_types = new_type_array;
371 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
375 /* resuse the type from the old target */
378 h = (idx << 2) | type;
381 case HANDLE_WEAK_TRACK:
382 val = (gpointer)HIDE_POINTER (val);
383 gc_handles [idx] = val;
384 gc_handle_types [idx] = type;
386 if (gc_handles [idx] != (gpointer)-1)
387 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
389 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
393 gc_handles [idx] = val;
394 gc_handle_types [idx] = type;
397 LeaveCriticalSection (&handle_section);
402 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
404 int idx = handle >> 2;
405 int type = handle & 0x3;
409 EnterCriticalSection (&handle_section);
412 g_assert (type == gc_handle_types [idx]);
413 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
414 if (gc_handles [idx] != (gpointer)-1)
415 GC_unregister_disappearing_link (&(gc_handles [idx]));
418 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
421 gc_handles [idx] = (gpointer)-1;
422 gc_handle_types [idx] = (guint8)-1;
423 LeaveCriticalSection (&handle_section);
427 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
430 int type = handle & 0x3;
435 EnterCriticalSection (&handle_section);
436 obj = gc_handles [handle >> 2];
437 g_assert (gc_handle_types [handle >> 2] == type);
438 LeaveCriticalSection (&handle_section);
439 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
440 obj = REVEAL_POINTER (obj);
441 if (obj == (MonoObject *) -1)
451 static HANDLE finalizer_event;
452 static volatile gboolean finished=FALSE;
454 static void finalize_notify (void)
457 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
460 SetEvent (finalizer_event);
464 collect_objects (gpointer key, gpointer value, gpointer user_data)
466 GPtrArray *arr = (GPtrArray*)user_data;
467 g_ptr_array_add (arr, key);
471 * finalize_domain_objects:
473 * Run the finalizers of all finalizable objects in req->domain.
476 finalize_domain_objects (DomainFinalizationReq *req)
480 MonoDomain *domain = req->domain;
482 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
484 * Since the domain is unloading, nobody is allowed to put
485 * new entries into the hash table. But finalize_object might
486 * remove entries from the hash table, so we make a copy.
488 objs = g_ptr_array_new ();
489 g_hash_table_foreach (domain->finalizable_objects_hash,
490 collect_objects, objs);
491 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
493 for (i = 0; i < objs->len; ++i) {
494 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
495 /* FIXME: Avoid finalizing threads, etc */
499 g_ptr_array_free (objs, TRUE);
502 //printf ("DONE.\n");
503 SetEvent (req->done_event);
505 /* FIXME: How to delete the event ? */
509 static guint32 finalizer_thread (gpointer unused)
513 mono_thread_new_init (GetCurrentThreadId (), &stack_start, NULL);
516 /* Wait to be notified that there's at least one
519 WaitForSingleObject (finalizer_event, INFINITE);
521 if (domains_to_finalize) {
522 EnterCriticalSection (&finalizer_mutex);
523 if (domains_to_finalize) {
524 DomainFinalizationReq *req = domains_to_finalize->data;
525 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
526 LeaveCriticalSection (&finalizer_mutex);
528 finalize_domain_objects (req);
531 LeaveCriticalSection (&finalizer_mutex);
535 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
538 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
539 * before the domain is unloaded.
541 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
542 * the 'mem_freed' variable is not initialized when there are no
543 * objects to finalize, which leads to strange behavior later on.
544 * The check is necessary to work around that bug.
546 if (GC_should_invoke_finalizers ()) {
547 GC_invoke_finalizers ();
550 SetEvent (pending_done_event);
553 SetEvent (shutdown_event);
559 * Enable or disable the separate finalizer thread.
560 * It's currently disabled because it still requires some
561 * work in the rest of the runtime.
563 #define ENABLE_FINALIZER_THREAD
565 #ifdef WITH_INCLUDED_LIBGC
567 extern void mono_gc_stop_world (void);
568 extern void mono_gc_start_world (void);
569 extern void mono_gc_push_all_stacks (void);
571 static void mono_gc_lock (void)
573 EnterCriticalSection (&allocator_section);
576 static void mono_gc_unlock (void)
578 LeaveCriticalSection (&allocator_section);
581 static GCThreadFunctions mono_gc_thread_vtable = {
589 mono_gc_push_all_stacks,
592 #endif /* WITH_INCLUDED_LIBGC */
594 void mono_gc_init (void)
596 InitializeCriticalSection (&handle_section);
597 InitializeCriticalSection (&allocator_section);
599 InitializeCriticalSection (&finalizer_mutex);
601 #ifdef WITH_INCLUDED_LIBGC
602 gc_thread_vtable = &mono_gc_thread_vtable;
605 #ifdef ENABLE_FINALIZER_THREAD
607 if (getenv ("GC_DONT_GC")) {
612 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
613 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
614 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
615 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL) {
616 g_assert_not_reached ();
619 GC_finalize_on_demand = 1;
620 GC_finalizer_notifier = finalize_notify;
622 /* Don't use mono_thread_create here, because we don't want
623 * the runtime to wait for this thread to exit when it's
626 gc_thread = CreateThread (NULL, mono_threads_get_default_stacksize (), finalizer_thread, NULL, 0, NULL);
627 if (gc_thread == NULL) {
628 g_assert_not_reached ();
633 void mono_gc_cleanup (void)
636 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
639 #ifdef ENABLE_FINALIZER_THREAD
641 ResetEvent (shutdown_event);
644 /* Finishing the finalizer thread, so wait a little bit... */
645 /* MS seems to wait for about 2 seconds */
647 * FIXME: This is not thread safe. If the finalizer thread keeps
648 * running, and the runtime is shut down, it will lead to a crash.
650 WaitForSingleObject (shutdown_event, 2000);
658 /* no Boehm GC support. */
659 void mono_gc_init (void)
661 InitializeCriticalSection (&handle_section);
664 void mono_gc_cleanup (void)