2 * sgen-alloc.c: Object allocation routines + managed allocators
5 * Paolo Molaro (lupus@ximian.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
9 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
10 * Copyright 2011 Xamarin, Inc.
11 * Copyright (C) 2012 Xamarin Inc
13 * This library is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU Library General Public
15 * License 2.0 as published by the Free Software Foundation;
17 * This library is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License 2.0 along with this library; if not, write to the Free
24 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 * ######################################################################
29 * ######## Object allocation
30 * ######################################################################
31 * This section of code deals with allocating memory for objects.
32 * There are several ways:
33 * *) allocate large objects
34 * *) allocate normal objects
35 * *) fast lock-free allocation
36 * *) allocation of pinned objects
42 #include "metadata/sgen-gc.h"
43 #include "metadata/sgen-protocol.h"
44 #include "metadata/sgen-memory-governor.h"
45 #include "metadata/profiler-private.h"
46 #include "metadata/marshal.h"
47 #include "metadata/method-builder.h"
48 #include "metadata/abi-details.h"
49 #include "utils/mono-memory-model.h"
50 #include "utils/mono-counters.h"
52 #define ALIGN_UP SGEN_ALIGN_UP
53 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
54 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
55 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
56 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
58 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
62 #include "mono/cil/opcode.def"
68 static gboolean use_managed_allocator = TRUE;
70 #ifdef HEAVY_STATISTICS
71 static long long stat_objects_alloced = 0;
72 static long long stat_bytes_alloced = 0;
73 static long long stat_bytes_alloced_los = 0;
78 * Allocation is done from a Thread Local Allocation Buffer (TLAB). TLABs are allocated
79 * from nursery fragments.
80 * tlab_next is the pointer to the space inside the TLAB where the next object will
82 * tlab_temp_end is the pointer to the end of the temporary space reserved for
83 * the allocation: it allows us to set the scan starts at reasonable intervals.
84 * tlab_real_end points to the end of the TLAB.
88 * FIXME: What is faster, a TLS variable pointing to a structure, or separate TLS
89 * variables for next+temp_end ?
92 static __thread char *tlab_start;
93 static __thread char *tlab_next;
94 static __thread char *tlab_temp_end;
95 static __thread char *tlab_real_end;
96 /* Used by the managed allocator/wbarrier */
97 static __thread char **tlab_next_addr;
100 #ifdef HAVE_KW_THREAD
101 #define TLAB_START tlab_start
102 #define TLAB_NEXT tlab_next
103 #define TLAB_TEMP_END tlab_temp_end
104 #define TLAB_REAL_END tlab_real_end
106 #define TLAB_START (__thread_info__->tlab_start)
107 #define TLAB_NEXT (__thread_info__->tlab_next)
108 #define TLAB_TEMP_END (__thread_info__->tlab_temp_end)
109 #define TLAB_REAL_END (__thread_info__->tlab_real_end)
113 alloc_degraded (MonoVTable *vtable, size_t size, gboolean for_mature)
115 static int last_major_gc_warned = -1;
116 static int num_degraded = 0;
121 if (last_major_gc_warned < gc_stats.major_gc_count) {
123 if (num_degraded == 1 || num_degraded == 3)
124 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "Warning: Degraded allocation. Consider increasing nursery-size if the warning persists.");
125 else if (num_degraded == 10)
126 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "Warning: Repeated degraded allocation. Consider increasing nursery-size.");
127 last_major_gc_warned = gc_stats.major_gc_count;
129 SGEN_ATOMIC_ADD_P (degraded_mode, size);
130 sgen_ensure_free_space (size);
132 if (sgen_need_major_collection (size))
133 sgen_perform_collection (size, GENERATION_OLD, "mature allocation failure", !for_mature);
137 p = major_collector.alloc_degraded (vtable, size);
140 MONO_GC_MAJOR_OBJ_ALLOC_MATURE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
142 binary_protocol_alloc_degraded (p, vtable, size);
143 MONO_GC_MAJOR_OBJ_ALLOC_DEGRADED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
150 zero_tlab_if_necessary (void *p, size_t size)
152 if (nursery_clear_policy == CLEAR_AT_TLAB_CREATION || nursery_clear_policy == CLEAR_AT_TLAB_CREATION_DEBUG) {
156 * This function is called for all allocations in
157 * TLABs. TLABs originate from fragments, which are
158 * initialized to be faux arrays. The remainder of
159 * the fragments are zeroed out at initialization for
160 * CLEAR_AT_GC, so here we just need to make sure that
161 * the array header is zeroed. Since we don't know
162 * whether we're called for the start of a fragment or
163 * for somewhere in between, we zero in any case, just
167 if (size >= sizeof (MonoArray))
168 memset (p, 0, sizeof (MonoArray));
170 static guint8 zeros [sizeof (MonoArray)];
172 SGEN_ASSERT (0, !memcmp (p, zeros, size), "TLAB segment must be zeroed out.");
178 * Provide a variant that takes just the vtable for small fixed-size objects.
179 * The aligned size is already computed and stored in vt->gc_descr.
180 * Note: every SGEN_SCAN_START_SIZE or so we are given the chance to do some special
181 * processing. We can keep track of where objects start, for example,
182 * so when we scan the thread stacks for pinned objects, we can start
183 * a search for the pinned object in SGEN_SCAN_START_SIZE chunks.
186 mono_gc_alloc_obj_nolock (MonoVTable *vtable, size_t size)
188 /* FIXME: handle OOM */
192 size_t real_size = size;
196 HEAVY_STAT (++stat_objects_alloced);
197 if (real_size <= SGEN_MAX_SMALL_OBJ_SIZE)
198 HEAVY_STAT (stat_bytes_alloced += size);
200 HEAVY_STAT (stat_bytes_alloced_los += size);
202 size = ALIGN_UP (size);
204 g_assert (vtable->gc_descr);
206 if (G_UNLIKELY (has_per_allocation_action)) {
207 static int alloc_count;
208 int current_alloc = InterlockedIncrement (&alloc_count);
210 if (collect_before_allocs) {
211 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
212 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
213 if (!degraded_mode && sgen_can_alloc_size (size) && real_size <= SGEN_MAX_SMALL_OBJ_SIZE) {
215 g_assert_not_reached ();
218 } else if (verify_before_allocs) {
219 if ((current_alloc % verify_before_allocs) == 0)
220 sgen_check_whole_heap_stw ();
225 * We must already have the lock here instead of after the
226 * fast path because we might be interrupted in the fast path
227 * (after confirming that new_next < TLAB_TEMP_END) by the GC,
228 * and we'll end up allocating an object in a fragment which
229 * no longer belongs to us.
231 * The managed allocator does not do this, but it's treated
232 * specially by the world-stopping code.
235 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE) {
236 p = sgen_los_alloc_large_inner (vtable, ALIGN_UP (real_size));
238 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
240 p = (void**)TLAB_NEXT;
241 /* FIXME: handle overflow */
242 new_next = (char*)p + size;
243 TLAB_NEXT = new_next;
245 if (G_LIKELY (new_next < TLAB_TEMP_END)) {
249 * FIXME: We might need a memory barrier here so the change to tlab_next is
250 * visible before the vtable store.
253 CANARIFY_ALLOC(p,real_size);
254 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
255 binary_protocol_alloc (p , vtable, size);
256 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
257 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
258 g_assert (*p == NULL);
259 mono_atomic_store_seq (p, vtable);
266 /* there are two cases: the object is too big or we run out of space in the TLAB */
267 /* we also reach here when the thread does its first allocation after a minor
268 * collection, since the tlab_ variables are initialized to NULL.
269 * there can be another case (from ORP), if we cooperate with the runtime a bit:
270 * objects that need finalizers can have the high bit set in their size
271 * so the above check fails and we can readily add the object to the queue.
272 * This avoids taking again the GC lock when registering, but this is moot when
273 * doing thread-local allocation, so it may not be a good idea.
275 if (TLAB_NEXT >= TLAB_REAL_END) {
276 int available_in_tlab;
278 * Run out of space in the TLAB. When this happens, some amount of space
279 * remains in the TLAB, but not enough to satisfy the current allocation
280 * request. Currently, we retire the TLAB in all cases, later we could
281 * keep it if the remaining space is above a treshold, and satisfy the
282 * allocation directly from the nursery.
285 /* when running in degraded mode, we continue allocing that way
286 * for a while, to decrease the number of useless nursery collections.
288 if (degraded_mode && degraded_mode < DEFAULT_NURSERY_SIZE)
289 return alloc_degraded (vtable, size, FALSE);
291 available_in_tlab = (int)(TLAB_REAL_END - TLAB_NEXT);//We'll never have tlabs > 2Gb
292 if (size > tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
293 /* Allocate directly from the nursery */
295 p = sgen_nursery_alloc (size);
297 sgen_ensure_free_space (real_size);
299 return alloc_degraded (vtable, size, FALSE);
301 p = sgen_nursery_alloc (size);
309 zero_tlab_if_necessary (p, size);
311 size_t alloc_size = 0;
313 SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
314 sgen_nursery_retire_region (p, available_in_tlab);
317 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
319 sgen_ensure_free_space (tlab_size);
321 return alloc_degraded (vtable, size, FALSE);
323 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
332 /* Allocate a new TLAB from the current nursery fragment */
333 TLAB_START = (char*)p;
334 TLAB_NEXT = TLAB_START;
335 TLAB_REAL_END = TLAB_START + alloc_size;
336 TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
338 zero_tlab_if_necessary (TLAB_START, alloc_size);
340 /* Allocate from the TLAB */
341 p = (void*)TLAB_NEXT;
343 sgen_set_nursery_scan_start ((char*)p);
346 /* Reached tlab_temp_end */
348 /* record the scan start so we can find pinned objects more easily */
349 sgen_set_nursery_scan_start ((char*)p);
350 /* we just bump tlab_temp_end as well */
351 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
352 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
354 CANARIFY_ALLOC(p,real_size);
358 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
359 binary_protocol_alloc (p, vtable, size);
360 if (G_UNLIKELY (MONO_GC_MAJOR_OBJ_ALLOC_LARGE_ENABLED ()|| MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ())) {
361 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
362 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
364 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
366 mono_atomic_store_seq (p, vtable);
373 mono_gc_try_alloc_obj_nolock (MonoVTable *vtable, size_t size)
378 size_t real_size = size;
382 size = ALIGN_UP (size);
383 SGEN_ASSERT (9, real_size >= sizeof (MonoObject), "Object too small");
385 g_assert (vtable->gc_descr);
386 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
389 if (G_UNLIKELY (size > tlab_size)) {
390 /* Allocate directly from the nursery */
391 p = sgen_nursery_alloc (size);
394 sgen_set_nursery_scan_start ((char*)p);
396 /*FIXME we should use weak memory ops here. Should help specially on x86. */
397 zero_tlab_if_necessary (p, size);
399 int available_in_tlab;
401 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
403 p = (void**)TLAB_NEXT;
404 /* FIXME: handle overflow */
405 new_next = (char*)p + size;
407 real_end = TLAB_REAL_END;
408 available_in_tlab = (int)(real_end - (char*)p);//We'll never have tlabs > 2Gb
410 if (G_LIKELY (new_next < real_end)) {
411 TLAB_NEXT = new_next;
413 /* Second case, we overflowed temp end */
414 if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
415 sgen_set_nursery_scan_start (new_next);
416 /* we just bump tlab_temp_end as well */
417 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
418 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
420 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
421 /* Allocate directly from the nursery */
422 p = sgen_nursery_alloc (size);
426 zero_tlab_if_necessary (p, size);
428 size_t alloc_size = 0;
430 sgen_nursery_retire_region (p, available_in_tlab);
431 new_next = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
432 p = (void**)new_next;
436 TLAB_START = (char*)new_next;
437 TLAB_NEXT = new_next + size;
438 TLAB_REAL_END = new_next + alloc_size;
439 TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
440 sgen_set_nursery_scan_start ((char*)p);
442 zero_tlab_if_necessary (new_next, alloc_size);
444 MONO_GC_NURSERY_TLAB_ALLOC ((mword)new_next, alloc_size);
448 HEAVY_STAT (++stat_objects_alloced);
449 HEAVY_STAT (stat_bytes_alloced += size);
451 CANARIFY_ALLOC(p,real_size);
452 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
453 binary_protocol_alloc (p, vtable, size);
454 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
455 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
456 g_assert (*p == NULL); /* FIXME disable this in non debug builds */
458 mono_atomic_store_seq (p, vtable);
464 mono_gc_alloc_obj (MonoVTable *vtable, size_t size)
469 if (!SGEN_CAN_ALIGN_UP (size))
472 #ifndef DISABLE_CRITICAL_REGION
474 if (G_UNLIKELY (has_per_allocation_action)) {
475 static int alloc_count;
476 int current_alloc = InterlockedIncrement (&alloc_count);
478 if (verify_before_allocs) {
479 if ((current_alloc % verify_before_allocs) == 0)
480 sgen_check_whole_heap_stw ();
482 if (collect_before_allocs) {
483 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
485 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
491 ENTER_CRITICAL_REGION;
492 res = mono_gc_try_alloc_obj_nolock (vtable, size);
494 EXIT_CRITICAL_REGION;
497 EXIT_CRITICAL_REGION;
500 res = mono_gc_alloc_obj_nolock (vtable, size);
502 if (G_UNLIKELY (!res))
503 return mono_gc_out_of_memory (size);
508 mono_gc_alloc_vector (MonoVTable *vtable, size_t size, uintptr_t max_length)
513 if (!SGEN_CAN_ALIGN_UP (size))
516 #ifndef DISABLE_CRITICAL_REGION
517 ENTER_CRITICAL_REGION;
518 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
520 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
521 arr->max_length = (mono_array_size_t)max_length;
522 EXIT_CRITICAL_REGION;
525 EXIT_CRITICAL_REGION;
530 arr = mono_gc_alloc_obj_nolock (vtable, size);
531 if (G_UNLIKELY (!arr)) {
533 return mono_gc_out_of_memory (size);
536 arr->max_length = (mono_array_size_t)max_length;
544 mono_gc_alloc_array (MonoVTable *vtable, size_t size, uintptr_t max_length, uintptr_t bounds_size)
547 MonoArrayBounds *bounds;
550 if (!SGEN_CAN_ALIGN_UP (size))
553 #ifndef DISABLE_CRITICAL_REGION
554 ENTER_CRITICAL_REGION;
555 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
557 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
558 arr->max_length = (mono_array_size_t)max_length;
560 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
561 arr->bounds = bounds;
562 EXIT_CRITICAL_REGION;
565 EXIT_CRITICAL_REGION;
570 arr = mono_gc_alloc_obj_nolock (vtable, size);
571 if (G_UNLIKELY (!arr)) {
573 return mono_gc_out_of_memory (size);
576 arr->max_length = (mono_array_size_t)max_length;
578 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
579 arr->bounds = bounds;
587 mono_gc_alloc_string (MonoVTable *vtable, size_t size, gint32 len)
592 if (!SGEN_CAN_ALIGN_UP (size))
595 #ifndef DISABLE_CRITICAL_REGION
596 ENTER_CRITICAL_REGION;
597 str = mono_gc_try_alloc_obj_nolock (vtable, size);
599 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
601 EXIT_CRITICAL_REGION;
604 EXIT_CRITICAL_REGION;
609 str = mono_gc_alloc_obj_nolock (vtable, size);
610 if (G_UNLIKELY (!str)) {
612 return mono_gc_out_of_memory (size);
623 * To be used for interned strings and possibly MonoThread, reflection handles.
624 * We may want to explicitly free these objects.
627 mono_gc_alloc_pinned_obj (MonoVTable *vtable, size_t size)
631 if (!SGEN_CAN_ALIGN_UP (size))
633 size = ALIGN_UP (size);
637 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
638 /* large objects are always pinned anyway */
639 p = sgen_los_alloc_large_inner (vtable, size);
641 SGEN_ASSERT (9, vtable->klass->inited, "class %s:%s is not initialized", vtable->klass->name_space, vtable->klass->name);
642 p = major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
645 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
646 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
647 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
649 MONO_GC_MAJOR_OBJ_ALLOC_PINNED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
650 binary_protocol_alloc_pinned (p, vtable, size);
657 mono_gc_alloc_mature (MonoVTable *vtable)
660 size_t size = vtable->klass->instance_size;
662 if (!SGEN_CAN_ALIGN_UP (size))
664 size = ALIGN_UP (size);
667 res = alloc_degraded (vtable, size, TRUE);
669 if (G_UNLIKELY (vtable->klass->has_finalize))
670 mono_object_register_finalizer ((MonoObject*)res);
676 mono_gc_alloc_fixed (size_t size, void *descr)
678 /* FIXME: do a single allocation */
679 void *res = calloc (1, size);
682 if (!mono_gc_register_root (res, size, descr)) {
690 mono_gc_free_fixed (void* addr)
692 mono_gc_deregister_root (addr);
697 sgen_init_tlab_info (SgenThreadInfo* info)
699 #ifndef HAVE_KW_THREAD
700 SgenThreadInfo *__thread_info__ = info;
703 info->tlab_start_addr = &TLAB_START;
704 info->tlab_next_addr = &TLAB_NEXT;
705 info->tlab_temp_end_addr = &TLAB_TEMP_END;
706 info->tlab_real_end_addr = &TLAB_REAL_END;
708 #ifdef HAVE_KW_THREAD
709 tlab_next_addr = &tlab_next;
714 * Clear the thread local TLAB variables for all threads.
717 sgen_clear_tlabs (void)
719 SgenThreadInfo *info;
721 FOREACH_THREAD (info) {
722 /* A new TLAB will be allocated when the thread does its first allocation */
723 *info->tlab_start_addr = NULL;
724 *info->tlab_next_addr = NULL;
725 *info->tlab_temp_end_addr = NULL;
726 *info->tlab_real_end_addr = NULL;
730 static MonoMethod* alloc_method_cache [ATYPE_NUM];
732 #ifdef MANAGED_ALLOCATION
733 /* FIXME: Do this in the JIT, where specialized allocation sequences can be created
734 * for each class. This is currently not easy to do, as it is hard to generate basic
735 * blocks + branches, but it is easy with the linear IL codebase.
737 * For this to work we'd need to solve the TLAB race, first. Now we
738 * require the allocator to be in a few known methods to make sure
739 * that they are executed atomically via the restart mechanism.
742 create_allocator (int atype)
745 guint32 slowpath_branch, max_size_branch;
746 MonoMethodBuilder *mb;
748 MonoMethodSignature *csig;
749 static gboolean registered = FALSE;
750 int tlab_next_addr_var, new_next_var;
752 const char *name = NULL;
753 AllocatorWrapperInfo *info;
755 #ifdef HAVE_KW_THREAD
756 int tlab_next_addr_offset = -1;
757 int tlab_temp_end_offset = -1;
759 MONO_THREAD_VAR_OFFSET (tlab_next_addr, tlab_next_addr_offset);
760 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
762 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_NEXT_ADDR, tlab_next_addr_offset);
763 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_TEMP_END, tlab_temp_end_offset);
765 g_assert (tlab_next_addr_offset != -1);
766 g_assert (tlab_temp_end_offset != -1);
770 mono_register_jit_icall (mono_gc_alloc_obj, "mono_gc_alloc_obj", mono_create_icall_signature ("object ptr int"), FALSE);
771 mono_register_jit_icall (mono_gc_alloc_vector, "mono_gc_alloc_vector", mono_create_icall_signature ("object ptr int int"), FALSE);
772 mono_register_jit_icall (mono_gc_alloc_string, "mono_gc_alloc_string", mono_create_icall_signature ("object ptr int int32"), FALSE);
776 if (atype == ATYPE_SMALL) {
779 } else if (atype == ATYPE_NORMAL) {
782 } else if (atype == ATYPE_VECTOR) {
784 name = "AllocVector";
785 } else if (atype == ATYPE_STRING) {
787 name = "AllocString";
789 g_assert_not_reached ();
792 csig = mono_metadata_signature_alloc (mono_defaults.corlib, num_params);
793 if (atype == ATYPE_STRING) {
794 csig->ret = &mono_defaults.string_class->byval_arg;
795 csig->params [0] = &mono_defaults.int_class->byval_arg;
796 csig->params [1] = &mono_defaults.int32_class->byval_arg;
798 csig->ret = &mono_defaults.object_class->byval_arg;
799 for (i = 0; i < num_params; ++i)
800 csig->params [i] = &mono_defaults.int_class->byval_arg;
803 mb = mono_mb_new (mono_defaults.object_class, name, MONO_WRAPPER_ALLOC);
806 size_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
807 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
808 /* size = vtable->klass->instance_size; */
809 mono_mb_emit_ldarg (mb, 0);
810 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
811 mono_mb_emit_byte (mb, CEE_ADD);
812 mono_mb_emit_byte (mb, CEE_LDIND_I);
813 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, instance_size));
814 mono_mb_emit_byte (mb, CEE_ADD);
815 /* FIXME: assert instance_size stays a 4 byte integer */
816 mono_mb_emit_byte (mb, CEE_LDIND_U4);
817 mono_mb_emit_byte (mb, CEE_CONV_I);
818 mono_mb_emit_stloc (mb, size_var);
819 } else if (atype == ATYPE_VECTOR) {
820 MonoExceptionClause *clause;
821 int pos, pos_leave, pos_error;
822 MonoClass *oom_exc_class;
826 * n > MONO_ARRAY_MAX_INDEX => OutOfMemoryException
827 * n < 0 => OverflowException
829 * We can do an unsigned comparison to catch both cases, then in the error
830 * case compare signed to distinguish between them.
832 mono_mb_emit_ldarg (mb, 1);
833 mono_mb_emit_icon (mb, MONO_ARRAY_MAX_INDEX);
834 mono_mb_emit_byte (mb, CEE_CONV_U);
835 pos = mono_mb_emit_short_branch (mb, CEE_BLE_UN_S);
837 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
838 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
839 mono_mb_emit_ldarg (mb, 1);
840 mono_mb_emit_icon (mb, 0);
841 pos_error = mono_mb_emit_short_branch (mb, CEE_BLT_S);
842 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
843 mono_mb_patch_short_branch (mb, pos_error);
844 mono_mb_emit_exception (mb, "OverflowException", NULL);
846 mono_mb_patch_short_branch (mb, pos);
848 clause = mono_image_alloc0 (mono_defaults.corlib, sizeof (MonoExceptionClause));
849 clause->try_offset = mono_mb_get_label (mb);
851 /* vtable->klass->sizes.element_size */
852 mono_mb_emit_ldarg (mb, 0);
853 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
854 mono_mb_emit_byte (mb, CEE_ADD);
855 mono_mb_emit_byte (mb, CEE_LDIND_I);
856 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, sizes));
857 mono_mb_emit_byte (mb, CEE_ADD);
858 mono_mb_emit_byte (mb, CEE_LDIND_U4);
859 mono_mb_emit_byte (mb, CEE_CONV_I);
862 mono_mb_emit_ldarg (mb, 1);
863 mono_mb_emit_byte (mb, CEE_MUL_OVF_UN);
864 /* + sizeof (MonoArray) */
865 mono_mb_emit_icon (mb, sizeof (MonoArray));
866 mono_mb_emit_byte (mb, CEE_ADD_OVF_UN);
867 mono_mb_emit_stloc (mb, size_var);
869 pos_leave = mono_mb_emit_branch (mb, CEE_LEAVE);
872 clause->flags = MONO_EXCEPTION_CLAUSE_NONE;
873 clause->try_len = mono_mb_get_pos (mb) - clause->try_offset;
874 clause->data.catch_class = mono_class_from_name (mono_defaults.corlib,
875 "System", "OverflowException");
876 g_assert (clause->data.catch_class);
877 clause->handler_offset = mono_mb_get_label (mb);
879 oom_exc_class = mono_class_from_name (mono_defaults.corlib,
880 "System", "OutOfMemoryException");
881 g_assert (oom_exc_class);
882 ctor = mono_class_get_method_from_name (oom_exc_class, ".ctor", 0);
885 mono_mb_emit_byte (mb, CEE_POP);
886 mono_mb_emit_op (mb, CEE_NEWOBJ, ctor);
887 mono_mb_emit_byte (mb, CEE_THROW);
889 clause->handler_len = mono_mb_get_pos (mb) - clause->handler_offset;
890 mono_mb_set_clauses (mb, 1, clause);
891 mono_mb_patch_branch (mb, pos_leave);
893 } else if (atype == ATYPE_STRING) {
897 * a string allocator method takes the args: (vtable, len)
899 * bytes = offsetof (MonoString, chars) + ((len + 1) * 2)
903 * bytes <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
907 * offsetof (MonoString, chars) + ((len + 1) * 2) <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
908 * len <= (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - offsetof (MonoString, chars)) / 2 - 1
910 mono_mb_emit_ldarg (mb, 1);
911 mono_mb_emit_icon (mb, (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - MONO_STRUCT_OFFSET (MonoString, chars)) / 2 - 1);
912 pos = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
914 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
915 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
916 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
917 mono_mb_patch_short_branch (mb, pos);
919 mono_mb_emit_ldarg (mb, 1);
920 mono_mb_emit_icon (mb, 1);
921 mono_mb_emit_byte (mb, MONO_CEE_SHL);
922 //WE manually fold the above + 2 here
923 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoString, chars) + 2);
924 mono_mb_emit_byte (mb, CEE_ADD);
925 mono_mb_emit_stloc (mb, size_var);
927 g_assert_not_reached ();
930 /* size += ALLOC_ALIGN - 1; */
931 mono_mb_emit_ldloc (mb, size_var);
932 mono_mb_emit_icon (mb, ALLOC_ALIGN - 1);
933 mono_mb_emit_byte (mb, CEE_ADD);
934 /* size &= ~(ALLOC_ALIGN - 1); */
935 mono_mb_emit_icon (mb, ~(ALLOC_ALIGN - 1));
936 mono_mb_emit_byte (mb, CEE_AND);
937 mono_mb_emit_stloc (mb, size_var);
939 /* if (size > MAX_SMALL_OBJ_SIZE) goto slowpath */
940 if (atype != ATYPE_SMALL) {
941 mono_mb_emit_ldloc (mb, size_var);
942 mono_mb_emit_icon (mb, MAX_SMALL_OBJ_SIZE);
943 max_size_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
947 * We need to modify tlab_next, but the JIT only supports reading, so we read
948 * another tls var holding its address instead.
951 /* tlab_next_addr (local) = tlab_next_addr (TLS var) */
952 tlab_next_addr_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
953 EMIT_TLS_ACCESS_NEXT_ADDR (mb);
954 mono_mb_emit_stloc (mb, tlab_next_addr_var);
956 /* p = (void**)tlab_next; */
957 p_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
958 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
959 mono_mb_emit_byte (mb, CEE_LDIND_I);
960 mono_mb_emit_stloc (mb, p_var);
962 /* new_next = (char*)p + size; */
963 new_next_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
964 mono_mb_emit_ldloc (mb, p_var);
965 mono_mb_emit_ldloc (mb, size_var);
966 mono_mb_emit_byte (mb, CEE_CONV_I);
967 mono_mb_emit_byte (mb, CEE_ADD);
968 mono_mb_emit_stloc (mb, new_next_var);
970 /* if (G_LIKELY (new_next < tlab_temp_end)) */
971 mono_mb_emit_ldloc (mb, new_next_var);
972 EMIT_TLS_ACCESS_TEMP_END (mb);
973 slowpath_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
976 if (atype != ATYPE_SMALL)
977 mono_mb_patch_short_branch (mb, max_size_branch);
979 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
980 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
982 /* FIXME: mono_gc_alloc_obj takes a 'size_t' as an argument, not an int32 */
983 mono_mb_emit_ldarg (mb, 0);
984 mono_mb_emit_ldloc (mb, size_var);
985 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
986 mono_mb_emit_icall (mb, mono_gc_alloc_obj);
987 } else if (atype == ATYPE_VECTOR) {
988 mono_mb_emit_ldarg (mb, 1);
989 mono_mb_emit_icall (mb, mono_gc_alloc_vector);
990 } else if (atype == ATYPE_STRING) {
991 mono_mb_emit_ldarg (mb, 1);
992 mono_mb_emit_icall (mb, mono_gc_alloc_string);
994 g_assert_not_reached ();
996 mono_mb_emit_byte (mb, CEE_RET);
999 mono_mb_patch_short_branch (mb, slowpath_branch);
1001 /* FIXME: Memory barrier */
1003 /* tlab_next = new_next */
1004 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
1005 mono_mb_emit_ldloc (mb, new_next_var);
1006 mono_mb_emit_byte (mb, CEE_STIND_I);
1008 /*The tlab store must be visible before the the vtable store. This could be replaced with a DDS but doing it with IL would be tricky. */
1009 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1010 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, (gpointer)StoreStoreBarrier);
1013 mono_mb_emit_ldloc (mb, p_var);
1014 mono_mb_emit_ldarg (mb, 0);
1015 mono_mb_emit_byte (mb, CEE_STIND_I);
1017 if (atype == ATYPE_VECTOR) {
1018 /* arr->max_length = max_length; */
1019 mono_mb_emit_ldloc (mb, p_var);
1020 mono_mb_emit_ldflda (mb, MONO_STRUCT_OFFSET (MonoArray, max_length));
1021 mono_mb_emit_ldarg (mb, 1);
1022 #ifdef MONO_BIG_ARRAYS
1023 mono_mb_emit_byte (mb, CEE_STIND_I);
1025 mono_mb_emit_byte (mb, CEE_STIND_I4);
1027 } else if (atype == ATYPE_STRING) {
1028 /* need to set length and clear the last char */
1029 /* s->length = len; */
1030 mono_mb_emit_ldloc (mb, p_var);
1031 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoString, length));
1032 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1033 mono_mb_emit_ldarg (mb, 1);
1034 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
1035 /* s->chars [len] = 0; */
1036 mono_mb_emit_ldloc (mb, p_var);
1037 mono_mb_emit_ldloc (mb, size_var);
1038 mono_mb_emit_icon (mb, 2);
1039 mono_mb_emit_byte (mb, MONO_CEE_SUB);
1040 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1041 mono_mb_emit_icon (mb, 0);
1042 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
1046 We must make sure both vtable and max_length are globaly visible before returning to managed land.
1048 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1049 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, (gpointer)StoreStoreBarrier);
1052 mono_mb_emit_ldloc (mb, p_var);
1053 mono_mb_emit_byte (mb, CEE_RET);
1056 res = mono_mb_create_method (mb, csig, 8);
1058 mono_method_get_header (res)->init_locals = FALSE;
1060 info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
1061 info->gc_name = "sgen";
1062 info->alloc_type = atype;
1063 mono_marshal_set_wrapper_info (res, info);
1070 * Generate an allocator method implementing the fast path of mono_gc_alloc_obj ().
1071 * The signature of the called method is:
1072 * object allocate (MonoVTable *vtable)
1075 mono_gc_get_managed_allocator (MonoClass *klass, gboolean for_box)
1077 #ifdef MANAGED_ALLOCATION
1079 #ifdef HAVE_KW_THREAD
1080 int tlab_next_offset = -1;
1081 int tlab_temp_end_offset = -1;
1082 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1083 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1085 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1088 if (collect_before_allocs)
1090 if (!mono_runtime_has_tls_get ())
1092 if (klass->instance_size > tlab_size)
1095 if (klass->has_finalize || mono_class_is_marshalbyref (klass) || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
1099 if (klass->byval_arg.type == MONO_TYPE_STRING)
1100 return mono_gc_get_managed_allocator_by_type (ATYPE_STRING);
1101 /* Generic classes have dynamic field and can go above MAX_SMALL_OBJ_SIZE. */
1102 if (ALIGN_TO (klass->instance_size, ALLOC_ALIGN) < MAX_SMALL_OBJ_SIZE && !mono_class_is_open_constructed_type (&klass->byval_arg))
1103 return mono_gc_get_managed_allocator_by_type (ATYPE_SMALL);
1105 return mono_gc_get_managed_allocator_by_type (ATYPE_NORMAL);
1112 mono_gc_get_managed_array_allocator (MonoClass *klass)
1114 #ifdef MANAGED_ALLOCATION
1115 #ifdef HAVE_KW_THREAD
1116 int tlab_next_offset = -1;
1117 int tlab_temp_end_offset = -1;
1118 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1119 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1121 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1125 if (klass->rank != 1)
1127 if (!mono_runtime_has_tls_get ())
1129 if (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS)
1131 if (has_per_allocation_action)
1133 g_assert (!mono_class_has_finalizer (klass) && !mono_class_is_marshalbyref (klass));
1135 return mono_gc_get_managed_allocator_by_type (ATYPE_VECTOR);
1142 sgen_set_use_managed_allocator (gboolean flag)
1144 use_managed_allocator = flag;
1148 mono_gc_get_managed_allocator_by_type (int atype)
1150 #ifdef MANAGED_ALLOCATION
1153 if (!use_managed_allocator)
1156 if (!mono_runtime_has_tls_get ())
1159 res = alloc_method_cache [atype];
1163 res = create_allocator (atype);
1165 if (alloc_method_cache [atype]) {
1166 mono_free_method (res);
1167 res = alloc_method_cache [atype];
1169 mono_memory_barrier ();
1170 alloc_method_cache [atype] = res;
1181 mono_gc_get_managed_allocator_types (void)
1187 sgen_is_managed_allocator (MonoMethod *method)
1191 for (i = 0; i < ATYPE_NUM; ++i)
1192 if (method == alloc_method_cache [i])
1198 sgen_has_managed_allocator (void)
1202 for (i = 0; i < ATYPE_NUM; ++i)
1203 if (alloc_method_cache [i])
1208 #ifdef HEAVY_STATISTICS
1210 sgen_alloc_init_heavy_stats (void)
1212 mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced);
1213 mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced);
1214 mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_los);
1218 #endif /*HAVE_SGEN_GC*/