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);
91 /* speedup later... and use a timeout */
92 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
94 /* Use _internal here, since this thread can enter a doomed appdomain */
95 mono_domain_set_internal (mono_object_domain (o));
97 mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
100 /* fixme: do something useful */
105 * Some of our objects may point to a different address than the address returned by GC_malloc()
106 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
107 * This also means that in the callback we need to adjust the pointer to get back the real
109 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
110 * since that, too, can cause the underlying pointer to be offset.
113 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
119 /* This assertion is not valid when GC_DEBUG is defined */
120 g_assert (GC_base (obj) == (char*)obj - offset);
123 if (mono_domain_is_unloading (obj->vtable->domain) && (callback != NULL))
125 * Can't register finalizers in a dying appdomain, since they
126 * could be invoked after the appdomain has been unloaded.
130 mono_domain_lock (obj->vtable->domain);
133 g_hash_table_insert (obj->vtable->domain->finalizable_objects_hash, obj,
136 g_hash_table_remove (obj->vtable->domain->finalizable_objects_hash, obj);
138 mono_domain_unlock (obj->vtable->domain);
140 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
145 mono_object_register_finalizer (MonoObject *obj)
147 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
148 object_register_finalizer (obj, run_finalize);
152 * mono_domain_finalize:
154 * Request finalization of all finalizable objects inside @domain. Wait
155 * @timeout msecs for the finalization to complete.
156 * Returns: TRUE if succeeded, FALSE if there was a timeout
160 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
162 DomainFinalizationReq *req;
167 * No need to create another thread 'cause the finalizer thread
168 * is still working and will take care of running the finalizers
177 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
179 req = g_new0 (DomainFinalizationReq, 1);
180 req->domain = domain;
181 req->done_event = done_event;
183 EnterCriticalSection (&finalizer_mutex);
185 domains_to_finalize = g_slist_append (domains_to_finalize, req);
187 LeaveCriticalSection (&finalizer_mutex);
189 /* Tell the finalizer thread to finalize this appdomain */
192 res = WaitForSingleObject (done_event, timeout);
194 CloseHandle (done_event);
195 //printf ("WAIT RES: %d.\n", res);
196 if (res == WAIT_TIMEOUT)
201 /* We don't support domain finalization without a GC */
207 ves_icall_System_GC_InternalCollect (int generation)
217 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
224 return GC_get_heap_size () - GC_get_free_bytes ();
231 ves_icall_System_GC_KeepAlive (MonoObject *obj)
241 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
245 object_register_finalizer (obj, run_finalize);
249 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
253 object_register_finalizer (obj, NULL);
257 ves_icall_System_GC_WaitForPendingFinalizers (void)
262 if (!GC_should_invoke_finalizers ())
265 if (mono_thread_current () == gc_thread)
266 /* Avoid deadlocks */
269 ResetEvent (pending_done_event);
271 /* g_print ("Waiting for pending finalizers....\n"); */
272 WaitForSingleObject (pending_done_event, INFINITE);
273 /* g_print ("Done pending....\n"); */
278 static CRITICAL_SECTION allocator_section;
279 static CRITICAL_SECTION handle_section;
280 static guint32 next_handle = 0;
281 static gpointer *gc_handles = NULL;
282 static guint8 *gc_handle_types = NULL;
283 static guint32 array_size = 0;
286 * The handle type is encoded in the lower two bits of the handle value:
300 * FIXME: make thread safe and reuse the array entries.
303 ves_icall_System_GCHandle_GetTarget (guint32 handle)
312 EnterCriticalSection (&handle_section);
313 g_assert (type == gc_handle_types [handle >> 2]);
314 obj = gc_handles [handle >> 2];
315 LeaveCriticalSection (&handle_section);
319 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
320 return REVEAL_POINTER (obj);
328 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
335 EnterCriticalSection (&handle_section);
336 /* Indexes start from 1 since 0 means the handle is not allocated */
338 if (idx >= array_size) {
341 guint8 *new_type_array;
344 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
345 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
348 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
349 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
350 /* need to re-register links for weak refs. test if GC_realloc needs the same */
351 for (i = 0; i < array_size; ++i) {
352 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
353 * inside libgc. I assume it will also break without the
354 * threaded finalizer, just that the stress test (bug 31333)
355 * deadlocks too early without it. Reverting to the previous
356 * version here stops the segfault.
358 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
360 if (((gulong)new_array [i]) & 0x1) {
362 if (gc_handles [i] != (gpointer)-1)
363 GC_unregister_disappearing_link (&(gc_handles [i]));
364 if (new_array [i] != (gpointer)-1)
365 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
370 gc_handles = new_array;
371 gc_handle_types = new_type_array;
373 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
377 /* resuse the type from the old target */
380 h = (idx << 2) | type;
383 case HANDLE_WEAK_TRACK:
384 val = (gpointer)HIDE_POINTER (val);
385 gc_handles [idx] = val;
386 gc_handle_types [idx] = type;
388 if (gc_handles [idx] != (gpointer)-1)
389 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
391 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
395 gc_handles [idx] = val;
396 gc_handle_types [idx] = type;
399 LeaveCriticalSection (&handle_section);
404 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
406 int idx = handle >> 2;
407 int type = handle & 0x3;
411 EnterCriticalSection (&handle_section);
414 g_assert (type == gc_handle_types [idx]);
415 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
416 if (gc_handles [idx] != (gpointer)-1)
417 GC_unregister_disappearing_link (&(gc_handles [idx]));
420 LeaveCriticalSection (&handle_section);
421 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
424 gc_handles [idx] = (gpointer)-1;
425 gc_handle_types [idx] = (guint8)-1;
426 LeaveCriticalSection (&handle_section);
430 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
433 int type = handle & 0x3;
438 EnterCriticalSection (&handle_section);
439 obj = gc_handles [handle >> 2];
440 g_assert (gc_handle_types [handle >> 2] == type);
441 LeaveCriticalSection (&handle_section);
442 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
443 obj = REVEAL_POINTER (obj);
444 if (obj == (MonoObject *) -1)
454 static HANDLE finalizer_event;
455 static volatile gboolean finished=FALSE;
457 static void finalize_notify (void)
460 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
463 SetEvent (finalizer_event);
467 collect_objects (gpointer key, gpointer value, gpointer user_data)
469 GPtrArray *arr = (GPtrArray*)user_data;
470 g_ptr_array_add (arr, key);
474 * finalize_domain_objects:
476 * Run the finalizers of all finalizable objects in req->domain.
479 finalize_domain_objects (DomainFinalizationReq *req)
483 MonoDomain *domain = req->domain;
485 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
487 * Since the domain is unloading, nobody is allowed to put
488 * new entries into the hash table. But finalize_object might
489 * remove entries from the hash table, so we make a copy.
491 objs = g_ptr_array_new ();
492 g_hash_table_foreach (domain->finalizable_objects_hash,
493 collect_objects, objs);
494 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
496 for (i = 0; i < objs->len; ++i) {
497 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
498 /* FIXME: Avoid finalizing threads, etc */
502 g_ptr_array_free (objs, TRUE);
505 //printf ("DONE.\n");
506 SetEvent (req->done_event);
508 /* FIXME: How to delete the event ? */
512 static guint32 finalizer_thread (gpointer unused)
516 gc_thread = mono_thread_current ();
518 SetEvent (thread_started_event);
521 /* Wait to be notified that there's at least one
524 WaitForSingleObject (finalizer_event, INFINITE);
526 if (domains_to_finalize) {
527 EnterCriticalSection (&finalizer_mutex);
528 if (domains_to_finalize) {
529 DomainFinalizationReq *req = domains_to_finalize->data;
530 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
531 LeaveCriticalSection (&finalizer_mutex);
533 finalize_domain_objects (req);
536 LeaveCriticalSection (&finalizer_mutex);
540 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
543 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
544 * before the domain is unloaded.
546 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
547 * the 'mem_freed' variable is not initialized when there are no
548 * objects to finalize, which leads to strange behavior later on.
549 * The check is necessary to work around that bug.
551 if (GC_should_invoke_finalizers ()) {
552 GC_invoke_finalizers ();
555 SetEvent (pending_done_event);
558 SetEvent (shutdown_event);
564 * Enable or disable the separate finalizer thread.
565 * It's currently disabled because it still requires some
566 * work in the rest of the runtime.
568 #define ENABLE_FINALIZER_THREAD
570 #ifdef WITH_INCLUDED_LIBGC
572 extern void mono_gc_stop_world (void);
573 extern void mono_gc_start_world (void);
574 extern void mono_gc_push_all_stacks (void);
576 static void mono_gc_lock (void)
578 EnterCriticalSection (&allocator_section);
581 static void mono_gc_unlock (void)
583 LeaveCriticalSection (&allocator_section);
586 static GCThreadFunctions mono_gc_thread_vtable = {
594 mono_gc_push_all_stacks,
597 #endif /* WITH_INCLUDED_LIBGC */
599 void mono_gc_init (void)
601 InitializeCriticalSection (&handle_section);
602 InitializeCriticalSection (&allocator_section);
604 InitializeCriticalSection (&finalizer_mutex);
606 #ifdef WITH_INCLUDED_LIBGC
607 gc_thread_vtable = &mono_gc_thread_vtable;
610 #ifdef ENABLE_FINALIZER_THREAD
612 if (getenv ("GC_DONT_GC")) {
617 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
618 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
619 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
620 thread_started_event = CreateEvent (NULL, TRUE, FALSE, NULL);
621 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL || thread_started_event == NULL) {
622 g_assert_not_reached ();
625 GC_finalize_on_demand = 1;
626 GC_finalizer_notifier = finalize_notify;
628 mono_thread_create (mono_domain_get (), finalizer_thread, NULL);
630 * Wait until the finalizer thread sets gc_thread since its value is needed
631 * by mono_thread_attach ()
633 WaitForSingleObject (thread_started_event, INFINITE);
637 void mono_gc_cleanup (void)
640 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
643 #ifdef ENABLE_FINALIZER_THREAD
645 ResetEvent (shutdown_event);
648 /* Finishing the finalizer thread, so wait a little bit... */
649 /* MS seems to wait for about 2 seconds */
651 * FIXME: This is not thread safe. If the finalizer thread keeps
652 * running, and the runtime is shut down, it will lead to a crash.
654 WaitForSingleObject (shutdown_event, 2000);
662 /* no Boehm GC support. */
663 void mono_gc_init (void)
665 InitializeCriticalSection (&handle_section);
668 void mono_gc_cleanup (void)
675 mono_gc_is_finalizer_thread (MonoThread *thread)
677 return thread == gc_thread;