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 CloseHandle (done_event);
201 //printf ("WAIT RES: %d.\n", res);
202 if (res == WAIT_TIMEOUT)
207 /* We don't support domain finalization without a GC */
213 ves_icall_System_GC_InternalCollect (int generation)
223 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
230 return GC_get_heap_size () - GC_get_free_bytes ();
237 ves_icall_System_GC_KeepAlive (MonoObject *obj)
247 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
251 object_register_finalizer (obj, run_finalize);
255 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
259 object_register_finalizer (obj, NULL);
263 ves_icall_System_GC_WaitForPendingFinalizers (void)
268 if (!GC_should_invoke_finalizers ())
271 if (mono_thread_current () == gc_thread)
272 /* Avoid deadlocks */
275 ResetEvent (pending_done_event);
277 /* g_print ("Waiting for pending finalizers....\n"); */
278 WaitForSingleObject (pending_done_event, INFINITE);
279 /* g_print ("Done pending....\n"); */
284 static CRITICAL_SECTION allocator_section;
285 static CRITICAL_SECTION handle_section;
286 static guint32 next_handle = 0;
287 static gpointer *gc_handles = NULL;
288 static guint8 *gc_handle_types = NULL;
289 static guint32 array_size = 0;
292 * The handle type is encoded in the lower two bits of the handle value:
306 * FIXME: make thread safe and reuse the array entries.
309 ves_icall_System_GCHandle_GetTarget (guint32 handle)
318 EnterCriticalSection (&handle_section);
319 g_assert (type == gc_handle_types [handle >> 2]);
320 obj = gc_handles [handle >> 2];
321 LeaveCriticalSection (&handle_section);
325 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
326 return REVEAL_POINTER (obj);
334 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
341 EnterCriticalSection (&handle_section);
342 /* Indexes start from 1 since 0 means the handle is not allocated */
344 if (idx >= array_size) {
347 guint8 *new_type_array;
350 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
351 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
354 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
355 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
356 /* need to re-register links for weak refs. test if GC_realloc needs the same */
357 for (i = 0; i < array_size; ++i) {
358 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
359 * inside libgc. I assume it will also break without the
360 * threaded finalizer, just that the stress test (bug 31333)
361 * deadlocks too early without it. Reverting to the previous
362 * version here stops the segfault.
364 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
366 if (((gulong)new_array [i]) & 0x1) {
368 if (gc_handles [i] != (gpointer)-1)
369 GC_unregister_disappearing_link (&(gc_handles [i]));
370 if (new_array [i] != (gpointer)-1)
371 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
376 gc_handles = new_array;
377 gc_handle_types = new_type_array;
379 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
383 /* resuse the type from the old target */
386 h = (idx << 2) | type;
389 case HANDLE_WEAK_TRACK:
390 val = (gpointer)HIDE_POINTER (val);
391 gc_handles [idx] = val;
392 gc_handle_types [idx] = type;
394 if (gc_handles [idx] != (gpointer)-1)
395 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
397 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
401 gc_handles [idx] = val;
402 gc_handle_types [idx] = type;
405 LeaveCriticalSection (&handle_section);
410 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
412 int idx = handle >> 2;
413 int type = handle & 0x3;
417 EnterCriticalSection (&handle_section);
420 g_assert (type == gc_handle_types [idx]);
421 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
422 if (gc_handles [idx] != (gpointer)-1)
423 GC_unregister_disappearing_link (&(gc_handles [idx]));
426 LeaveCriticalSection (&handle_section);
427 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
430 gc_handles [idx] = (gpointer)-1;
431 gc_handle_types [idx] = (guint8)-1;
432 LeaveCriticalSection (&handle_section);
436 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
439 int type = handle & 0x3;
444 EnterCriticalSection (&handle_section);
445 obj = gc_handles [handle >> 2];
446 g_assert (gc_handle_types [handle >> 2] == type);
447 LeaveCriticalSection (&handle_section);
448 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
449 obj = REVEAL_POINTER (obj);
450 if (obj == (MonoObject *) -1)
460 static HANDLE finalizer_event;
461 static volatile gboolean finished=FALSE;
463 static void finalize_notify (void)
466 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
469 SetEvent (finalizer_event);
473 collect_objects (gpointer key, gpointer value, gpointer user_data)
475 GPtrArray *arr = (GPtrArray*)user_data;
476 g_ptr_array_add (arr, key);
480 * finalize_domain_objects:
482 * Run the finalizers of all finalizable objects in req->domain.
485 finalize_domain_objects (DomainFinalizationReq *req)
489 MonoDomain *domain = req->domain;
491 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
493 * Since the domain is unloading, nobody is allowed to put
494 * new entries into the hash table. But finalize_object might
495 * remove entries from the hash table, so we make a copy.
497 objs = g_ptr_array_new ();
498 g_hash_table_foreach (domain->finalizable_objects_hash,
499 collect_objects, objs);
500 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
502 for (i = 0; i < objs->len; ++i) {
503 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
504 /* FIXME: Avoid finalizing threads, etc */
508 g_ptr_array_free (objs, TRUE);
511 //printf ("DONE.\n");
512 SetEvent (req->done_event);
514 /* FIXME: How to delete the event ? */
518 static guint32 finalizer_thread (gpointer unused)
520 gc_thread = mono_thread_current ();
522 SetEvent (thread_started_event);
525 /* Wait to be notified that there's at least one
528 WaitForSingleObject (finalizer_event, INFINITE);
530 if (domains_to_finalize) {
531 EnterCriticalSection (&finalizer_mutex);
532 if (domains_to_finalize) {
533 DomainFinalizationReq *req = domains_to_finalize->data;
534 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
535 LeaveCriticalSection (&finalizer_mutex);
537 finalize_domain_objects (req);
540 LeaveCriticalSection (&finalizer_mutex);
544 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
547 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
548 * before the domain is unloaded.
550 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
551 * the 'mem_freed' variable is not initialized when there are no
552 * objects to finalize, which leads to strange behavior later on.
553 * The check is necessary to work around that bug.
555 if (GC_should_invoke_finalizers ()) {
556 GC_invoke_finalizers ();
559 SetEvent (pending_done_event);
562 SetEvent (shutdown_event);
568 * Enable or disable the separate finalizer thread.
569 * It's currently disabled because it still requires some
570 * work in the rest of the runtime.
572 #define ENABLE_FINALIZER_THREAD
574 #ifdef WITH_INCLUDED_LIBGC
576 extern void mono_gc_stop_world (void);
577 extern void mono_gc_start_world (void);
578 extern void mono_gc_push_all_stacks (void);
580 static void mono_gc_lock (void)
582 EnterCriticalSection (&allocator_section);
585 static void mono_gc_unlock (void)
587 LeaveCriticalSection (&allocator_section);
590 static GCThreadFunctions mono_gc_thread_vtable = {
598 mono_gc_push_all_stacks,
601 #endif /* WITH_INCLUDED_LIBGC */
603 void mono_gc_init (void)
605 InitializeCriticalSection (&handle_section);
606 InitializeCriticalSection (&allocator_section);
608 InitializeCriticalSection (&finalizer_mutex);
610 #ifdef WITH_INCLUDED_LIBGC
611 gc_thread_vtable = &mono_gc_thread_vtable;
614 #ifdef ENABLE_FINALIZER_THREAD
616 if (getenv ("GC_DONT_GC")) {
621 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
622 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
623 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
624 thread_started_event = CreateEvent (NULL, TRUE, FALSE, NULL);
625 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL || thread_started_event == NULL) {
626 g_assert_not_reached ();
629 GC_finalize_on_demand = 1;
630 GC_finalizer_notifier = finalize_notify;
632 mono_thread_create (mono_domain_get (), finalizer_thread, NULL);
634 * Wait until the finalizer thread sets gc_thread since its value is needed
635 * by mono_thread_attach ()
637 WaitForSingleObject (thread_started_event, INFINITE);
641 void mono_gc_cleanup (void)
644 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
647 #ifdef ENABLE_FINALIZER_THREAD
649 ResetEvent (shutdown_event);
652 /* Finishing the finalizer thread, so wait a little bit... */
653 /* MS seems to wait for about 2 seconds */
655 * FIXME: This is not thread safe. If the finalizer thread keeps
656 * running, and the runtime is shut down, it will lead to a crash.
658 WaitForSingleObject (shutdown_event, 2000);
665 mono_gc_disable (void)
671 mono_gc_enable (void)
678 /* no Boehm GC support. */
679 void mono_gc_init (void)
681 InitializeCriticalSection (&handle_section);
684 void mono_gc_cleanup (void)
689 mono_gc_disable (void)
694 mono_gc_enable (void)
701 mono_gc_is_finalizer_thread (MonoThread *thread)
703 return thread == gc_thread;