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 void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*));
48 static void finalize_notify (void);
49 static HANDLE pending_done_event;
50 static HANDLE shutdown_event;
54 * actually, we might want to queue the finalize requests in a separate thread,
55 * but we need to be careful about the execution domain of the thread...
58 run_finalize (void *obj, void *data)
60 MonoObject *exc = NULL;
62 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
64 if (finalize_slot < 0) {
66 for (i = 0; i < mono_defaults.object_class->vtable_size; ++i) {
67 MonoMethod *cm = mono_defaults.object_class->vtable [i];
69 if (!strcmp (cm->name, "Finalize")) {
76 mono_domain_lock (o->vtable->domain);
78 o2 = g_hash_table_lookup (o->vtable->domain->finalizable_objects_hash, o);
80 mono_domain_unlock (o->vtable->domain);
83 /* Already finalized somehow */
86 /* make sure the finalizer is not called again if the object is resurrected */
87 object_register_finalizer (obj, NULL);
88 /* speedup later... and use a timeout */
89 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
91 /* Use _internal here, since this thread can enter a doomed appdomain */
92 mono_domain_set_internal (mono_object_domain (o));
94 mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
97 /* fixme: do something useful */
102 * Some of our objects may point to a different address than the address returned by GC_malloc()
103 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
104 * This also means that in the callback we need to adjust the pointer to get back the real
106 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
107 * since that, too, can cause the underlying pointer to be offset.
110 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
116 /* This assertion is not valid when GC_DEBUG is defined */
117 g_assert (GC_base (obj) == (char*)obj - offset);
120 if (mono_domain_is_unloading (obj->vtable->domain) && (callback != NULL))
122 * Can't register finalizers in a dying appdomain, since they
123 * could be invoked after the appdomain has been unloaded.
127 mono_domain_lock (obj->vtable->domain);
130 g_hash_table_insert (obj->vtable->domain->finalizable_objects_hash, obj,
133 g_hash_table_remove (obj->vtable->domain->finalizable_objects_hash, obj);
135 mono_domain_unlock (obj->vtable->domain);
137 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
142 mono_object_register_finalizer (MonoObject *obj)
144 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
145 object_register_finalizer (obj, run_finalize);
149 * mono_domain_finalize:
151 * Request finalization of all finalizable objects inside @domain. Wait
152 * @timeout msecs for the finalization to complete.
153 * Returns: TRUE if succeeded, FALSE if there was a timeout
157 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
159 DomainFinalizationReq *req;
164 * No need to create another thread 'cause the finalizer thread
165 * is still working and will take care of running the finalizers
172 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
174 req = g_new0 (DomainFinalizationReq, 1);
175 req->domain = domain;
176 req->done_event = done_event;
178 EnterCriticalSection (&finalizer_mutex);
180 domains_to_finalize = g_slist_append (domains_to_finalize, req);
182 LeaveCriticalSection (&finalizer_mutex);
184 /* Tell the finalizer thread to finalize this appdomain */
187 res = WaitForSingleObject (done_event, timeout);
189 //printf ("WAIT RES: %d.\n", res);
190 if (res == WAIT_TIMEOUT)
197 ves_icall_System_GC_InternalCollect (int generation)
207 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
214 return GC_get_heap_size () - GC_get_free_bytes ();
221 ves_icall_System_GC_KeepAlive (MonoObject *obj)
231 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
235 object_register_finalizer (obj, run_finalize);
239 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
243 object_register_finalizer (obj, NULL);
247 ves_icall_System_GC_WaitForPendingFinalizers (void)
252 if (!GC_should_invoke_finalizers ())
255 ResetEvent (pending_done_event);
257 /* g_print ("Waiting for pending finalizers....\n"); */
258 WaitForSingleObject (pending_done_event, INFINITE);
259 /* g_print ("Done pending....\n"); */
264 static CRITICAL_SECTION allocator_section;
265 static CRITICAL_SECTION handle_section;
266 static guint32 next_handle = 0;
267 static gpointer *gc_handles = NULL;
268 static guint8 *gc_handle_types = NULL;
269 static guint32 array_size = 0;
272 * The handle type is encoded in the lower two bits of the handle value:
286 * FIXME: make thread safe and reuse the array entries.
289 ves_icall_System_GCHandle_GetTarget (guint32 handle)
298 EnterCriticalSection (&handle_section);
299 g_assert (type == gc_handle_types [handle >> 2]);
300 obj = gc_handles [handle >> 2];
301 LeaveCriticalSection (&handle_section);
305 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
306 return REVEAL_POINTER (obj);
314 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
321 EnterCriticalSection (&handle_section);
322 /* Indexes start from 1 since 0 means the handle is not allocated */
324 if (idx >= array_size) {
327 guint8 *new_type_array;
330 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
331 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
334 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
335 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
336 /* need to re-register links for weak refs. test if GC_realloc needs the same */
337 for (i = 0; i < array_size; ++i) {
338 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
339 * inside libgc. I assume it will also break without the
340 * threaded finalizer, just that the stress test (bug 31333)
341 * deadlocks too early without it. Reverting to the previous
342 * version here stops the segfault.
344 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
346 if (((gulong)new_array [i]) & 0x1) {
348 if (gc_handles [i] != (gpointer)-1)
349 GC_unregister_disappearing_link (&(gc_handles [i]));
350 if (new_array [i] != (gpointer)-1)
351 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
356 gc_handles = new_array;
357 gc_handle_types = new_type_array;
359 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
363 /* resuse the type from the old target */
366 h = (idx << 2) | type;
369 case HANDLE_WEAK_TRACK:
370 val = (gpointer)HIDE_POINTER (val);
371 gc_handles [idx] = val;
372 gc_handle_types [idx] = type;
374 if (gc_handles [idx] != (gpointer)-1)
375 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
377 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
381 gc_handles [idx] = val;
382 gc_handle_types [idx] = type;
385 LeaveCriticalSection (&handle_section);
390 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
392 int idx = handle >> 2;
393 int type = handle & 0x3;
397 EnterCriticalSection (&handle_section);
400 g_assert (type == gc_handle_types [idx]);
401 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
402 if (gc_handles [idx] != (gpointer)-1)
403 GC_unregister_disappearing_link (&(gc_handles [idx]));
406 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
409 gc_handles [idx] = (gpointer)-1;
410 gc_handle_types [idx] = (guint8)-1;
411 LeaveCriticalSection (&handle_section);
415 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
418 int type = handle & 0x3;
423 EnterCriticalSection (&handle_section);
424 obj = gc_handles [handle >> 2];
425 g_assert (gc_handle_types [handle >> 2] == type);
426 LeaveCriticalSection (&handle_section);
427 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
428 obj = REVEAL_POINTER (obj);
429 if (obj == (MonoObject *) -1)
439 static HANDLE finalizer_event;
440 static volatile gboolean finished=FALSE;
442 static void finalize_notify (void)
445 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
448 SetEvent (finalizer_event);
452 collect_objects (gpointer key, gpointer value, gpointer user_data)
454 GPtrArray *arr = (GPtrArray*)user_data;
455 g_ptr_array_add (arr, key);
459 * finalize_domain_objects:
461 * Run the finalizers of all finalizable objects in req->domain.
464 finalize_domain_objects (DomainFinalizationReq *req)
468 MonoDomain *domain = req->domain;
470 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
472 * Since the domain is unloading, nobody is allowed to put
473 * new entries into the hash table. But finalize_object might
474 * remove entries from the hash table, so we make a copy.
476 objs = g_ptr_array_new ();
477 g_hash_table_foreach (domain->finalizable_objects_hash,
478 collect_objects, objs);
479 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
481 for (i = 0; i < objs->len; ++i) {
482 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
483 /* FIXME: Avoid finalizing threads, etc */
487 g_ptr_array_free (objs, TRUE);
490 //printf ("DONE.\n");
491 SetEvent (req->done_event);
493 /* FIXME: How to delete the event ? */
497 static guint32 finalizer_thread (gpointer unused)
501 mono_thread_new_init (GetCurrentThreadId (), &stack_start, NULL);
504 /* Wait to be notified that there's at least one
507 WaitForSingleObject (finalizer_event, INFINITE);
509 if (domains_to_finalize) {
510 EnterCriticalSection (&finalizer_mutex);
511 if (domains_to_finalize) {
512 DomainFinalizationReq *req = domains_to_finalize->data;
513 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
514 LeaveCriticalSection (&finalizer_mutex);
516 finalize_domain_objects (req);
519 LeaveCriticalSection (&finalizer_mutex);
523 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
526 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
527 * before the domain is unloaded.
529 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
530 * the 'mem_freed' variable is not initialized when there are no
531 * objects to finalize, which leads to strange behavior later on.
532 * The check is necessary to work around that bug.
534 if (GC_should_invoke_finalizers ()) {
535 GC_invoke_finalizers ();
538 SetEvent (pending_done_event);
541 SetEvent (shutdown_event);
547 * Enable or disable the separate finalizer thread.
548 * It's currently disabled because it still requires some
549 * work in the rest of the runtime.
551 #define ENABLE_FINALIZER_THREAD
553 #ifdef WITH_INCLUDED_LIBGC
555 extern void mono_gc_stop_world (void);
556 extern void mono_gc_start_world (void);
557 extern void mono_gc_push_all_stacks (void);
559 static void mono_gc_lock (void)
561 EnterCriticalSection (&allocator_section);
564 static void mono_gc_unlock (void)
566 LeaveCriticalSection (&allocator_section);
569 static GCThreadFunctions mono_gc_thread_vtable = {
577 mono_gc_push_all_stacks,
580 #endif /* WITH_INCLUDED_LIBGC */
582 void mono_gc_init (void)
586 InitializeCriticalSection (&handle_section);
587 InitializeCriticalSection (&allocator_section);
589 InitializeCriticalSection (&finalizer_mutex);
591 #ifdef WITH_INCLUDED_LIBGC
592 gc_thread_vtable = &mono_gc_thread_vtable;
595 #ifdef ENABLE_FINALIZER_THREAD
597 if (getenv ("GC_DONT_GC")) {
602 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
603 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
604 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
605 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL) {
606 g_assert_not_reached ();
609 GC_finalize_on_demand = 1;
610 GC_finalizer_notifier = finalize_notify;
612 /* Don't use mono_thread_create here, because we don't want
613 * the runtime to wait for this thread to exit when it's
616 gc_thread = CreateThread (NULL, mono_threads_get_default_stacksize (), finalizer_thread, NULL, 0, NULL);
617 if (gc_thread == NULL) {
618 g_assert_not_reached ();
623 void mono_gc_cleanup (void)
626 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
629 #ifdef ENABLE_FINALIZER_THREAD
630 ResetEvent (shutdown_event);
634 /* Finishing the finalizer thread, so wait a little bit... */
635 /* MS seems to wait for about 2 seconds */
637 * FIXME: This is not thread safe. If the finalizer thread keeps
638 * running, and the runtime is shut down, it will lead to a crash.
640 WaitForSingleObject (shutdown_event, 2000);
648 /* no Boehm GC support. */
649 void mono_gc_init (void)
651 InitializeCriticalSection (&handle_section);
654 void mono_gc_cleanup (void)