mono/metadata/gc.c

   1 /*
   2  * metadata/gc.c: GC icalls.
   3  *
   4  * Author: Paolo Molaro <lupus@ximian.com>
   5  *
   6  * (C) 2002 Ximian, Inc.
   7  */
   8
   9 #include <config.h>
  10 #include <glib.h>
  11 #include <string.h>
  12
  13 #include <mono/metadata/gc.h>
  14 #include <mono/metadata/threads.h>
  15 #include <mono/metadata/tabledefs.h>
  16 #if HAVE_BOEHM_GC
  17 #define GC_I_HIDE_POINTERS
  18 #include <gc/gc.h>
  19 #else
  20 #define HIDE_POINTER(v) (v)
  21 #define REVEAL_POINTER(v) (v)
  22 #endif
  23
  24 static int finalize_slot = -1;
  25
  26 /*
  27  * actually, we might want to queue the finalize requests in a separate thread,
  28  * but we need to be careful about the execution domain of the thread...
  29  */
  30 static void
  31 run_finalize (void *obj, void *data)
  32 {
  33         MonoObject *exc = NULL;
  34         MonoObject *o;
  35         o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
  36
  37         if (finalize_slot < 0) {
  38                 int i;
  39                 for (i = 0; i < mono_defaults.object_class->vtable_size; ++i) {
  40                         MonoMethod *cm = mono_defaults.object_class->vtable [i];
  41
  42                         if (!strcmp (cm->name, "Finalize")) {
  43                                 finalize_slot = i;
  44                                 break;
  45                         }
  46                 }
  47         }
  48         /* speedup later... and use a timeout */
  49         /*g_print ("Finalize run on %s\n", mono_object_class (o)->name);*/
  50         mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
  51
  52         if (exc) {
  53                 /* fixme: do something useful */
  54         }
  55 }
  56
  57 /*
  58  * Some of our objects may point to a different address than the address returned by GC_malloc()
  59  * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
  60  * This also means that in the callback we need to adjust the pointer to get back the real
  61  * MonoObject*.
  62  * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
  63  * since that, too, can cause the underlying pointer to be offset.
  64  */
  65 static void
  66 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
  67 {
  68 #if HAVE_BOEHM_GC
  69         guint offset = 0;
  70
  71         g_assert (GC_base (obj) == (char*)obj - offset);
  72         GC_register_finalizer ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
  73 #endif
  74 }
  75
  76 void
  77 mono_object_register_finalizer (MonoObject *obj)
  78 {
  79         object_register_finalizer (obj, run_finalize);
  80 }
  81
  82 /*
  83  * to speedup, at class init time, check if a class or struct
  84  * have fields that need to be finalized and set a flag.
  85  */
  86 static void
  87 finalize_fields (MonoClass *class, char *data, gboolean instance, GHashTable *todo) {
  88         int i;
  89         MonoClassField *field;
  90         MonoObject *obj;
  91
  92         /*if (!instance)
  93                 g_print ("Finalize statics on on %s\n", class->name);*/
  94         if (instance && class->valuetype)
  95                 data -= sizeof (MonoObject);
  96         do {
  97                 for (i = 0; i < class->field.count; ++i) {
  98                         field = &class->fields [i];
  99                         if (instance) {
 100                                 if (field->type->attrs & FIELD_ATTRIBUTE_STATIC)
 101                                         continue;
 102                         } else {
 103                                 if (!(field->type->attrs & FIELD_ATTRIBUTE_STATIC))
 104                                         continue;
 105                         }
 106                         switch (field->type->type) {
 107                         case MONO_TYPE_OBJECT:
 108                         case MONO_TYPE_CLASS:
 109                                 obj = *((MonoObject**)(data + field->offset));
 110                                 if (obj) {
 111                                         if (mono_object_class (obj)->has_finalize) {
 112                                                 /* disable the registered finalizer */
 113                                                 object_register_finalizer (obj, NULL);
 114                                                 run_finalize (obj, NULL);
 115                                         } else {
 116                                                 /*
 117                                                  * if the type doesn't have a finalizer, we finalize
 118                                                  * the fields ourselves just like we do for structs.
 119                                                  * Disabled for now: how do we handle loops?
 120                                                  */
 121                                                 /*finalize_fields (mono_object_class (obj), obj, TRUE, todo);*/
 122                                         }
 123                                 }
 124                                 break;
 125                         case MONO_TYPE_VALUETYPE: {
 126                                 MonoClass *fclass = mono_class_from_mono_type (field->type);
 127                                 if (fclass->enumtype)
 128                                         continue;
 129                                 /*finalize_fields (fclass, data + field->offset, TRUE, todo);*/
 130                                 break;
 131                         }
 132                         case MONO_TYPE_ARRAY:
 133                         case MONO_TYPE_SZARRAY:
 134                                 /* FIXME: foreach item... */
 135                                 break;
 136                         }
 137                 }
 138                 if (!instance)
 139                         return;
 140                 class = class->parent;
 141         } while (class);
 142 }
 143
 144 static void
 145 finalize_static_data (MonoClass *class, MonoVTable *vtable, GHashTable *todo) {
 146
 147         if (class->enumtype || !vtable->data)
 148                 return;
 149         finalize_fields (class, vtable->data, FALSE, todo);
 150 }
 151
 152 void
 153 mono_domain_finalize (MonoDomain *domain) {
 154
 155         GHashTable *todo = g_hash_table_new (NULL, NULL);
 156 #if HAVE_BOEHM_GC
 157         GC_gcollect ();
 158 #endif
 159         mono_g_hash_table_foreach (domain->class_vtable_hash, (GHFunc)finalize_static_data, todo);
 160         /* FIXME: finalize objects in todo... */
 161         g_hash_table_destroy (todo);
 162 }
 163
 164 void
 165 ves_icall_System_GC_InternalCollect (int generation)
 166 {
 167 #if HAVE_BOEHM_GC
 168         GC_gcollect ();
 169 #endif
 170 }
 171
 172 gint64
 173 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
 174 {
 175 #if HAVE_BOEHM_GC
 176         if (forceCollection)
 177                 GC_gcollect ();
 178         return GC_get_heap_size ();
 179 #else
 180         return 0;
 181 #endif
 182 }
 183
 184 void
 185 ves_icall_System_GC_KeepAlive (MonoObject *obj)
 186 {
 187         /*
 188          * Does nothing.
 189          */
 190 }
 191
 192 void
 193 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
 194 {
 195         object_register_finalizer (obj, run_finalize);
 196 }
 197
 198 void
 199 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
 200 {
 201         object_register_finalizer (obj, NULL);
 202 }
 203
 204 void
 205 ves_icall_System_GC_WaitForPendingFinalizers (void)
 206 {
 207 }
 208
 209 /*static CRITICAL_SECTION handle_section;*/
 210 static guint32 next_handle = 0;
 211 static gpointer *gc_handles = NULL;
 212 static guint32 array_size = 0;
 213
 214 /*
 215  * The handle type is encoded in the lower two bits of the handle value:
 216  * 0 -> normal
 217  * 1 -> pinned
 218  * 2 -> weak
 219  */
 220
 221 /*
 222  * FIXME: make thread safe and reuse the array entries.
 223  */
 224 MonoObject *
 225 ves_icall_System_GCHandle_GetTarget (guint32 handle)
 226 {
 227         MonoObject *obj;
 228
 229         if (gc_handles) {
 230                 obj = gc_handles [handle >> 2];
 231                 if ((handle & 0x3) > 1)
 232                         return REVEAL_POINTER (obj);
 233                 return obj;
 234         }
 235         return NULL;
 236 }
 237
 238 guint32
 239 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
 240 {
 241         gpointer val = obj;
 242         guint32 h, idx = next_handle++;
 243
 244         if (idx >= array_size) {
 245 #if HAVE_BOEHM_GC
 246                 gpointer *new_array;
 247                 if (!array_size)
 248                         array_size = 16;
 249                 new_array = GC_malloc (sizeof (gpointer) * (array_size * 2));
 250                 if (gc_handles) {
 251                         int i;
 252                         memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
 253                         /* need to re-register links for weak refs. test if GC_realloc needs the same */
 254                         for (i = 0; i < array_size; ++i) {
 255                                 if (((gulong)new_array [i]) & 0x1) { /* all and only disguised pointers have it set */
 256                                         GC_general_register_disappearing_link (&(new_array [i]), REVEAL_POINTER (new_array [i]));
 257                                 }
 258                         }
 259                 }
 260                 array_size *= 2;
 261                 gc_handles = new_array;
 262 #else
 263                 g_error ("No GCHandle support built-in");
 264 #endif
 265         }
 266         h = idx << 2;
 267
 268         /* resuse the type from the old target */
 269         if (type == -1)
 270                 type =  handle & 0x3;
 271         switch (type) {
 272         case 0:
 273         case 1:
 274                 h |= type;
 275                 gc_handles [idx] = val;
 276                 break;
 277         default:
 278                 h |= 2;
 279                 val = (gpointer)HIDE_POINTER (val);
 280                 gc_handles [idx] = val;
 281 #if HAVE_BOEHM_GC
 282                 GC_general_register_disappearing_link (&(gc_handles [idx]), obj);
 283 #else
 284                 g_error ("No weakref support");
 285 #endif
 286                 break;
 287         }
 288         return h;
 289 }
 290
 291 void
 292 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
 293 {
 294         gc_handles [handle >> 2] = (gpointer)-1;
 295 }
 296
 297 gpointer
 298 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
 299 {
 300         MonoObject *obj;
 301
 302         if (gc_handles) {
 303                 obj = gc_handles [handle >> 2];
 304                 if ((handle & 0x3) > 1)
 305                         return REVEAL_POINTER (obj);
 306                 return obj;
 307         }
 308         return NULL;
 309 }
 310
 311