2 * boehm-gc.c: GC implementation using either the installed or included Boehm GC.
7 #define GC_I_HIDE_POINTERS
8 #include <mono/os/gc_wrapper.h>
9 #include <mono/metadata/mono-gc.h>
10 #include <mono/metadata/gc-internal.h>
11 #include <mono/metadata/profiler-private.h>
12 #include <mono/metadata/class-internals.h>
13 #include <mono/metadata/method-builder.h>
14 #include <mono/metadata/opcodes.h>
15 #include <mono/utils/mono-logger.h>
19 #ifdef USE_INCLUDED_LIBGC
22 #define THREAD_LOCAL_ALLOC 1
23 #include "private/pthread_support.h"
27 mono_gc_warning (char *msg, GC_word arg)
29 mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_GC, msg, (unsigned long)arg);
33 mono_gc_base_init (void)
37 GC_oom_fn = mono_gc_out_of_memory;
38 GC_set_warn_proc (mono_gc_warning);
39 GC_finalize_on_demand = 1;
40 GC_finalizer_notifier = mono_gc_finalize_notify;
42 #ifdef HAVE_GC_GCJ_MALLOC
43 GC_init_gcj_malloc (5, NULL);
48 mono_gc_collect (int generation)
54 mono_gc_max_generation (void)
60 mono_gc_get_generation (MonoObject *object)
66 mono_gc_collection_count (int generation)
72 mono_gc_add_memory_pressure (gint64 value)
77 mono_gc_get_used_size (void)
79 return GC_get_heap_size () - GC_get_free_bytes ();
83 mono_gc_get_heap_size (void)
85 return GC_get_heap_size ();
89 mono_gc_disable (void)
94 g_assert_not_reached ();
101 #ifdef HAVE_GC_ENABLE
104 g_assert_not_reached ();
109 mono_gc_is_gc_thread (void)
111 #ifdef USE_INCLUDED_LIBGC
112 return GC_thread_is_registered ();
118 extern int GC_thread_register_foreign (void *base_addr);
121 mono_gc_register_thread (void *baseptr)
123 if (mono_gc_is_gc_thread())
125 #if defined(USE_INCLUDED_LIBGC) && !defined(PLATFORM_WIN32)
126 return GC_thread_register_foreign (baseptr);
133 mono_object_is_alive (MonoObject* o)
135 #ifdef USE_INCLUDED_LIBGC
136 return GC_is_marked (o);
142 #ifdef USE_INCLUDED_LIBGC
145 on_gc_notification (GCEventType event)
147 mono_profiler_gc_event ((MonoGCEvent) event, 0);
151 on_gc_heap_resize (size_t new_size)
153 mono_profiler_gc_heap_resize (new_size);
157 mono_gc_enable_events (void)
159 GC_notify_event = on_gc_notification;
160 GC_on_heap_resize = on_gc_heap_resize;
166 mono_gc_enable_events (void)
173 mono_gc_register_root (char *start, size_t size, void *descr)
175 /* for some strange reason, they want one extra byte on the end */
176 GC_add_roots (start, start + size + 1);
182 mono_gc_weak_link_add (void **link_addr, MonoObject *obj)
184 /* libgc requires that we use HIDE_POINTER... */
185 *link_addr = (void*)HIDE_POINTER (obj);
186 GC_GENERAL_REGISTER_DISAPPEARING_LINK (link_addr, obj);
190 mono_gc_weak_link_remove (void **link_addr)
192 GC_unregister_disappearing_link (link_addr);
197 mono_gc_weak_link_get (void **link_addr)
199 MonoObject *obj = REVEAL_POINTER (*link_addr);
200 if (obj == (MonoObject *) -1)
206 mono_gc_make_descr_from_bitmap (gsize *bitmap, int numbits)
212 mono_gc_alloc_fixed (size_t size, void *descr)
214 return GC_MALLOC (size);
218 mono_gc_free_fixed (void* addr)
223 mono_gc_invoke_finalizers (void)
225 /* There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
226 * the 'mem_freed' variable is not initialized when there are no
227 * objects to finalize, which leads to strange behavior later on.
228 * The check is necessary to work around that bug.
230 if (GC_should_invoke_finalizers ())
231 return GC_invoke_finalizers ();
236 mono_gc_pending_finalizers (void)
238 return GC_should_invoke_finalizers ();
242 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
244 *(void**)field_ptr = value;
248 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
250 *(void**)slot_ptr = value;
254 mono_gc_wbarrier_arrayref_copy (MonoArray *arr, gpointer slot_ptr, int count)
256 /* no need to do anything */
260 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
262 *(void**)ptr = value;
266 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
271 mono_gc_wbarrier_object (MonoObject *object)
275 #if defined(USE_INCLUDED_LIBGC) && defined(USE_COMPILER_TLS) && defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
276 extern __thread MONO_TLS_FAST void* GC_thread_tls;
277 #include "metadata-internals.h"
283 while (!(v & (1 << i)))
290 ATYPE_FREEPTR_FOR_BOX,
298 create_allocator (int atype, int offset)
300 int index_var, bytes_var, my_fl_var, my_entry_var;
301 guint32 no_freelist_branch, not_small_enough_branch = 0;
302 guint32 size_overflow_branch = 0;
303 MonoMethodBuilder *mb;
305 MonoMethodSignature *csig;
307 if (atype == ATYPE_STRING) {
308 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 2);
309 csig->ret = &mono_defaults.string_class->byval_arg;
310 csig->params [0] = &mono_defaults.int_class->byval_arg;
311 csig->params [1] = &mono_defaults.int32_class->byval_arg;
313 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
314 csig->ret = &mono_defaults.object_class->byval_arg;
315 csig->params [0] = &mono_defaults.int_class->byval_arg;
318 mb = mono_mb_new (mono_defaults.object_class, "Alloc", MONO_WRAPPER_ALLOC);
319 bytes_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
320 if (atype == ATYPE_STRING) {
321 /* a string alloator method takes the args: (vtable, len) */
322 /* bytes = (sizeof (MonoString) + ((len + 1) * 2)); */
323 mono_mb_emit_ldarg (mb, 1);
324 mono_mb_emit_icon (mb, 1);
325 mono_mb_emit_byte (mb, MONO_CEE_ADD);
326 mono_mb_emit_icon (mb, 1);
327 mono_mb_emit_byte (mb, MONO_CEE_SHL);
328 // sizeof (MonoString) might include padding
329 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, chars));
330 mono_mb_emit_byte (mb, MONO_CEE_ADD);
331 mono_mb_emit_stloc (mb, bytes_var);
333 /* bytes = vtable->klass->instance_size */
334 mono_mb_emit_ldarg (mb, 0);
335 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
336 mono_mb_emit_byte (mb, MONO_CEE_ADD);
337 mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
338 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, instance_size));
339 mono_mb_emit_byte (mb, MONO_CEE_ADD);
340 /* FIXME: assert instance_size stays a 4 byte integer */
341 mono_mb_emit_byte (mb, MONO_CEE_LDIND_U4);
342 mono_mb_emit_stloc (mb, bytes_var);
345 /* this is needed for strings/arrays only as the other big types are never allocated with this method */
346 if (atype == ATYPE_STRING) {
348 /* if (!SMALL_ENOUGH (bytes)) jump slow_path;*/
349 mono_mb_emit_ldloc (mb, bytes_var);
350 mono_mb_emit_icon (mb, (NFREELISTS-1) * GRANULARITY);
351 not_small_enough_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
352 /* check for overflow */
353 mono_mb_emit_ldloc (mb, bytes_var);
354 mono_mb_emit_icon (mb, sizeof (MonoString));
355 size_overflow_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
358 /* int index = INDEX_FROM_BYTES(bytes); */
359 index_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
361 mono_mb_emit_ldloc (mb, bytes_var);
362 mono_mb_emit_icon (mb, GRANULARITY - 1);
363 mono_mb_emit_byte (mb, MONO_CEE_ADD);
364 mono_mb_emit_icon (mb, shift_amount (GRANULARITY));
365 mono_mb_emit_byte (mb, MONO_CEE_SHR_UN);
366 mono_mb_emit_icon (mb, shift_amount (sizeof (gpointer)));
367 mono_mb_emit_byte (mb, MONO_CEE_SHL);
368 /* index var is already adjusted into bytes */
369 mono_mb_emit_stloc (mb, index_var);
371 my_fl_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
372 my_entry_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
373 /* my_fl = ((GC_thread)tsd) -> ptrfree_freelists + index; */
374 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
375 mono_mb_emit_byte (mb, 0x0D); /* CEE_MONO_TLS */
376 mono_mb_emit_i4 (mb, offset);
377 if (atype == ATYPE_FREEPTR || atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING)
378 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, ptrfree_freelists));
379 else if (atype == ATYPE_NORMAL)
380 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, normal_freelists));
381 else if (atype == ATYPE_GCJ)
382 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, gcj_freelists));
384 g_assert_not_reached ();
385 mono_mb_emit_byte (mb, MONO_CEE_ADD);
386 mono_mb_emit_ldloc (mb, index_var);
387 mono_mb_emit_byte (mb, MONO_CEE_ADD);
388 mono_mb_emit_stloc (mb, my_fl_var);
390 /* my_entry = *my_fl; */
391 mono_mb_emit_ldloc (mb, my_fl_var);
392 mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
393 mono_mb_emit_stloc (mb, my_entry_var);
395 /* if (EXPECT((word)my_entry >= HBLKSIZE, 1)) { */
396 mono_mb_emit_ldloc (mb, my_entry_var);
397 mono_mb_emit_icon (mb, HBLKSIZE);
398 no_freelist_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
400 /* ptr_t next = obj_link(my_entry); *my_fl = next; */
401 mono_mb_emit_ldloc (mb, my_fl_var);
402 mono_mb_emit_ldloc (mb, my_entry_var);
403 mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
404 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
406 /* set the vtable and clear the words in the object */
407 mono_mb_emit_ldloc (mb, my_entry_var);
408 mono_mb_emit_ldarg (mb, 0);
409 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
411 if (atype == ATYPE_FREEPTR) {
412 int start_var, end_var, start_loop;
413 /* end = my_entry + bytes; start = my_entry + sizeof (gpointer);
415 start_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
416 end_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
417 mono_mb_emit_ldloc (mb, my_entry_var);
418 mono_mb_emit_ldloc (mb, bytes_var);
419 mono_mb_emit_byte (mb, MONO_CEE_ADD);
420 mono_mb_emit_stloc (mb, end_var);
421 mono_mb_emit_ldloc (mb, my_entry_var);
422 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
423 mono_mb_emit_byte (mb, MONO_CEE_ADD);
424 mono_mb_emit_stloc (mb, start_var);
428 * } while (start < end);
430 start_loop = mono_mb_get_label (mb);
431 mono_mb_emit_ldloc (mb, start_var);
432 mono_mb_emit_icon (mb, 0);
433 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
434 mono_mb_emit_ldloc (mb, start_var);
435 mono_mb_emit_icon (mb, sizeof (gpointer));
436 mono_mb_emit_byte (mb, MONO_CEE_ADD);
437 mono_mb_emit_stloc (mb, start_var);
439 mono_mb_emit_ldloc (mb, start_var);
440 mono_mb_emit_ldloc (mb, end_var);
441 mono_mb_emit_byte (mb, MONO_CEE_BLT_UN_S);
442 mono_mb_emit_byte (mb, start_loop - (mono_mb_get_label (mb) + 1));
443 } else if (atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING) {
444 /* need to clear just the sync pointer */
445 mono_mb_emit_ldloc (mb, my_entry_var);
446 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
447 mono_mb_emit_byte (mb, MONO_CEE_ADD);
448 mono_mb_emit_icon (mb, 0);
449 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
452 if (atype == ATYPE_STRING) {
453 /* need to set length and clear the last char */
454 /* s->length = len; */
455 mono_mb_emit_ldloc (mb, my_entry_var);
456 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, length));
457 mono_mb_emit_byte (mb, MONO_CEE_ADD);
458 mono_mb_emit_ldarg (mb, 1);
459 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
460 /* s->chars [len] = 0; */
461 mono_mb_emit_ldloc (mb, my_entry_var);
462 mono_mb_emit_ldloc (mb, bytes_var);
463 mono_mb_emit_icon (mb, 2);
464 mono_mb_emit_byte (mb, MONO_CEE_SUB);
465 mono_mb_emit_byte (mb, MONO_CEE_ADD);
466 mono_mb_emit_icon (mb, 0);
467 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
470 /* return my_entry; */
471 mono_mb_emit_ldloc (mb, my_entry_var);
472 mono_mb_emit_byte (mb, MONO_CEE_RET);
474 mono_mb_patch_short_branch (mb, no_freelist_branch);
475 if (not_small_enough_branch > 0)
476 mono_mb_patch_short_branch (mb, not_small_enough_branch);
477 if (size_overflow_branch > 0)
478 mono_mb_patch_short_branch (mb, size_overflow_branch);
479 /* the slow path: we just call back into the runtime */
480 if (atype == ATYPE_STRING) {
481 mono_mb_emit_ldarg (mb, 1);
482 mono_mb_emit_icall (mb, mono_string_alloc);
484 mono_mb_emit_ldarg (mb, 0);
485 mono_mb_emit_icall (mb, mono_object_new_specific);
488 mono_mb_emit_byte (mb, MONO_CEE_RET);
490 res = mono_mb_create_method (mb, csig, 8);
492 mono_method_get_header (res)->init_locals = FALSE;
496 static MonoMethod* alloc_method_cache [ATYPE_NUM];
497 #define GC_NO_DESCRIPTOR ((gpointer)(0 | GC_DS_LENGTH))
500 * If possible, generate a managed method that can quickly allocate objects in class
501 * @klass. The method will typically have an thread-local inline allocation sequence.
502 * The signature of the called method is:
503 * object allocate (MonoVTable *vtable)
504 * Some of the logic here is similar to mono_class_get_allocation_ftn () i object.c,
506 * The thread local alloc logic is taken from libgc/pthread_support.c.
510 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
514 MonoClass *klass = vtable->klass;
515 MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
517 /*g_print ("thread tls: %d\n", offset);*/
520 if (!SMALL_ENOUGH (klass->instance_size))
522 if (klass->has_finalize || klass->marshalbyref || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
526 if (klass->byval_arg.type == MONO_TYPE_STRING) {
527 atype = ATYPE_STRING;
528 } else if (!klass->has_references) {
530 atype = ATYPE_FREEPTR_FOR_BOX;
532 atype = ATYPE_FREEPTR;
536 * disabled because we currently do a runtime choice anyway, to
537 * deal with multiple appdomains.
538 if (vtable->gc_descr != GC_NO_DESCRIPTOR)
541 atype = ATYPE_NORMAL;
544 return mono_gc_get_managed_allocator_by_type (atype);
548 * mono_gc_get_managed_allocator_id:
550 * Return a type for the managed allocator method MANAGED_ALLOC which can later be passed
551 * to mono_gc_get_managed_allocator_by_type () to get back this allocator method. This can be
552 * used by the AOT code to encode references to managed allocator methods.
555 mono_gc_get_managed_allocator_type (MonoMethod *managed_alloc)
560 for (i = 0; i < ATYPE_NUM; ++i) {
561 if (alloc_method_cache [i] == managed_alloc) {
562 mono_loader_unlock ();
566 mono_loader_unlock ();
572 * mono_gc_get_managed_allocator_by_type:
574 * Return a managed allocator method corresponding to allocator type ATYPE.
577 mono_gc_get_managed_allocator_by_type (int atype)
581 MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
584 res = alloc_method_cache [atype];
586 res = alloc_method_cache [atype] = create_allocator (atype, offset);
587 mono_loader_unlock ();
594 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
600 mono_gc_get_managed_allocator_type (MonoMethod *managed_alloc)
606 mono_gc_get_managed_allocator_by_type (int atype)
613 #endif /* no Boehm GC */