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 "utils/mono-memory-model.h"
49 #include "utils/mono-counters.h"
51 #define ALIGN_UP SGEN_ALIGN_UP
52 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
53 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
54 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
55 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
57 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
61 #include "mono/cil/opcode.def"
67 static gboolean use_managed_allocator = TRUE;
69 #ifdef HEAVY_STATISTICS
70 static long long stat_objects_alloced = 0;
71 static long long stat_bytes_alloced = 0;
72 static long long stat_bytes_alloced_los = 0;
77 * Allocation is done from a Thread Local Allocation Buffer (TLAB). TLABs are allocated
78 * from nursery fragments.
79 * tlab_next is the pointer to the space inside the TLAB where the next object will
81 * tlab_temp_end is the pointer to the end of the temporary space reserved for
82 * the allocation: it allows us to set the scan starts at reasonable intervals.
83 * tlab_real_end points to the end of the TLAB.
87 * FIXME: What is faster, a TLS variable pointing to a structure, or separate TLS
88 * variables for next+temp_end ?
91 static __thread char *tlab_start;
92 static __thread char *tlab_next;
93 static __thread char *tlab_temp_end;
94 static __thread char *tlab_real_end;
95 /* Used by the managed allocator/wbarrier */
96 static __thread char **tlab_next_addr;
100 #define TLAB_START tlab_start
101 #define TLAB_NEXT tlab_next
102 #define TLAB_TEMP_END tlab_temp_end
103 #define TLAB_REAL_END tlab_real_end
105 #define TLAB_START (__thread_info__->tlab_start)
106 #define TLAB_NEXT (__thread_info__->tlab_next)
107 #define TLAB_TEMP_END (__thread_info__->tlab_temp_end)
108 #define TLAB_REAL_END (__thread_info__->tlab_real_end)
112 alloc_degraded (MonoVTable *vtable, size_t size, gboolean for_mature)
114 static int last_major_gc_warned = -1;
115 static int num_degraded = 0;
120 if (last_major_gc_warned < stat_major_gcs) {
122 if (num_degraded == 1 || num_degraded == 3)
123 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "Warning: Degraded allocation. Consider increasing nursery-size if the warning persists.");
124 else if (num_degraded == 10)
125 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "Warning: Repeated degraded allocation. Consider increasing nursery-size.");
126 last_major_gc_warned = stat_major_gcs;
128 InterlockedExchangeAdd (°raded_mode, size);
129 sgen_ensure_free_space (size);
131 if (sgen_need_major_collection (size))
132 sgen_perform_collection (size, GENERATION_OLD, "mature allocation failure", !for_mature);
136 p = major_collector.alloc_degraded (vtable, size);
139 MONO_GC_MAJOR_OBJ_ALLOC_MATURE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
141 binary_protocol_alloc_degraded (p, vtable, size);
142 MONO_GC_MAJOR_OBJ_ALLOC_DEGRADED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
149 zero_tlab_if_necessary (void *p, size_t size)
151 if (nursery_clear_policy == CLEAR_AT_TLAB_CREATION) {
155 * This function is called for all allocations in
156 * TLABs. TLABs originate from fragments, which are
157 * initialized to be faux arrays. The remainder of
158 * the fragments are zeroed out at initialization for
159 * CLEAR_AT_GC, so here we just need to make sure that
160 * the array header is zeroed. Since we don't know
161 * whether we're called for the start of a fragment or
162 * for somewhere in between, we zero in any case, just
166 if (size >= sizeof (MonoArray))
167 memset (p, 0, sizeof (MonoArray));
169 static guint8 zeros [sizeof (MonoArray)];
171 SGEN_ASSERT (0, !memcmp (p, zeros, size), "TLAB segment must be zeroed out.");
177 * Provide a variant that takes just the vtable for small fixed-size objects.
178 * The aligned size is already computed and stored in vt->gc_descr.
179 * Note: every SGEN_SCAN_START_SIZE or so we are given the chance to do some special
180 * processing. We can keep track of where objects start, for example,
181 * so when we scan the thread stacks for pinned objects, we can start
182 * a search for the pinned object in SGEN_SCAN_START_SIZE chunks.
185 mono_gc_alloc_obj_nolock (MonoVTable *vtable, size_t size)
187 /* FIXME: handle OOM */
192 HEAVY_STAT (++stat_objects_alloced);
193 if (size <= SGEN_MAX_SMALL_OBJ_SIZE)
194 HEAVY_STAT (stat_bytes_alloced += size);
196 HEAVY_STAT (stat_bytes_alloced_los += size);
198 size = ALIGN_UP (size);
200 g_assert (vtable->gc_descr);
202 if (G_UNLIKELY (has_per_allocation_action)) {
203 static int alloc_count;
204 int current_alloc = InterlockedIncrement (&alloc_count);
206 if (collect_before_allocs) {
207 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
208 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
209 if (!degraded_mode && sgen_can_alloc_size (size) && size <= SGEN_MAX_SMALL_OBJ_SIZE) {
211 g_assert_not_reached ();
214 } else if (verify_before_allocs) {
215 if ((current_alloc % verify_before_allocs) == 0)
216 sgen_check_whole_heap_stw ();
221 * We must already have the lock here instead of after the
222 * fast path because we might be interrupted in the fast path
223 * (after confirming that new_next < TLAB_TEMP_END) by the GC,
224 * and we'll end up allocating an object in a fragment which
225 * no longer belongs to us.
227 * The managed allocator does not do this, but it's treated
228 * specially by the world-stopping code.
231 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
232 p = sgen_los_alloc_large_inner (vtable, size);
234 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
236 p = (void**)TLAB_NEXT;
237 /* FIXME: handle overflow */
238 new_next = (char*)p + size;
239 TLAB_NEXT = new_next;
241 if (G_LIKELY (new_next < TLAB_TEMP_END)) {
245 * FIXME: We might need a memory barrier here so the change to tlab_next is
246 * visible before the vtable store.
249 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
250 binary_protocol_alloc (p , vtable, size);
251 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
252 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
253 g_assert (*p == NULL);
254 mono_atomic_store_seq (p, vtable);
261 /* there are two cases: the object is too big or we run out of space in the TLAB */
262 /* we also reach here when the thread does its first allocation after a minor
263 * collection, since the tlab_ variables are initialized to NULL.
264 * there can be another case (from ORP), if we cooperate with the runtime a bit:
265 * objects that need finalizers can have the high bit set in their size
266 * so the above check fails and we can readily add the object to the queue.
267 * This avoids taking again the GC lock when registering, but this is moot when
268 * doing thread-local allocation, so it may not be a good idea.
270 if (TLAB_NEXT >= TLAB_REAL_END) {
271 int available_in_tlab;
273 * Run out of space in the TLAB. When this happens, some amount of space
274 * remains in the TLAB, but not enough to satisfy the current allocation
275 * request. Currently, we retire the TLAB in all cases, later we could
276 * keep it if the remaining space is above a treshold, and satisfy the
277 * allocation directly from the nursery.
280 /* when running in degraded mode, we continue allocing that way
281 * for a while, to decrease the number of useless nursery collections.
283 if (degraded_mode && degraded_mode < DEFAULT_NURSERY_SIZE)
284 return alloc_degraded (vtable, size, FALSE);
286 available_in_tlab = TLAB_REAL_END - TLAB_NEXT;
287 if (size > tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
288 /* Allocate directly from the nursery */
290 p = sgen_nursery_alloc (size);
292 sgen_ensure_free_space (size);
294 return alloc_degraded (vtable, size, FALSE);
296 p = sgen_nursery_alloc (size);
304 zero_tlab_if_necessary (p, size);
306 size_t alloc_size = 0;
308 SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
309 sgen_nursery_retire_region (p, available_in_tlab);
312 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
314 sgen_ensure_free_space (tlab_size);
316 return alloc_degraded (vtable, size, FALSE);
318 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
327 /* Allocate a new TLAB from the current nursery fragment */
328 TLAB_START = (char*)p;
329 TLAB_NEXT = TLAB_START;
330 TLAB_REAL_END = TLAB_START + alloc_size;
331 TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
333 zero_tlab_if_necessary (TLAB_START, alloc_size);
335 /* Allocate from the TLAB */
336 p = (void*)TLAB_NEXT;
338 sgen_set_nursery_scan_start ((char*)p);
341 /* Reached tlab_temp_end */
343 /* record the scan start so we can find pinned objects more easily */
344 sgen_set_nursery_scan_start ((char*)p);
345 /* we just bump tlab_temp_end as well */
346 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
347 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
352 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
353 binary_protocol_alloc (p, vtable, size);
354 if (G_UNLIKELY (MONO_GC_MAJOR_OBJ_ALLOC_LARGE_ENABLED ()|| MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ())) {
355 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
356 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
358 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
360 mono_atomic_store_seq (p, vtable);
367 mono_gc_try_alloc_obj_nolock (MonoVTable *vtable, size_t size)
373 size = ALIGN_UP (size);
374 SGEN_ASSERT (9, size >= sizeof (MonoObject), "Object too small");
376 g_assert (vtable->gc_descr);
377 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
380 if (G_UNLIKELY (size > tlab_size)) {
381 /* Allocate directly from the nursery */
382 p = sgen_nursery_alloc (size);
385 sgen_set_nursery_scan_start ((char*)p);
387 /*FIXME we should use weak memory ops here. Should help specially on x86. */
388 zero_tlab_if_necessary (p, size);
390 int available_in_tlab;
392 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
394 p = (void**)TLAB_NEXT;
395 /* FIXME: handle overflow */
396 new_next = (char*)p + size;
398 real_end = TLAB_REAL_END;
399 available_in_tlab = real_end - (char*)p;
401 if (G_LIKELY (new_next < real_end)) {
402 TLAB_NEXT = new_next;
404 /* Second case, we overflowed temp end */
405 if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
406 sgen_set_nursery_scan_start (new_next);
407 /* we just bump tlab_temp_end as well */
408 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
409 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
411 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
412 /* Allocate directly from the nursery */
413 p = sgen_nursery_alloc (size);
417 zero_tlab_if_necessary (p, size);
419 size_t alloc_size = 0;
421 sgen_nursery_retire_region (p, available_in_tlab);
422 new_next = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
423 p = (void**)new_next;
427 TLAB_START = (char*)new_next;
428 TLAB_NEXT = new_next + size;
429 TLAB_REAL_END = new_next + alloc_size;
430 TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
431 sgen_set_nursery_scan_start ((char*)p);
433 zero_tlab_if_necessary (new_next, alloc_size);
435 MONO_GC_NURSERY_TLAB_ALLOC ((mword)new_next, alloc_size);
439 HEAVY_STAT (++stat_objects_alloced);
440 HEAVY_STAT (stat_bytes_alloced += size);
442 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
443 binary_protocol_alloc (p, vtable, size);
444 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
445 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
446 g_assert (*p == NULL); /* FIXME disable this in non debug builds */
448 mono_atomic_store_seq (p, vtable);
454 mono_gc_alloc_obj (MonoVTable *vtable, size_t size)
458 if (!SGEN_CAN_ALIGN_UP (size))
461 #ifndef DISABLE_CRITICAL_REGION
464 if (G_UNLIKELY (has_per_allocation_action)) {
465 static int alloc_count;
466 int current_alloc = InterlockedIncrement (&alloc_count);
468 if (verify_before_allocs) {
469 if ((current_alloc % verify_before_allocs) == 0)
470 sgen_check_whole_heap_stw ();
472 if (collect_before_allocs) {
473 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
475 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
481 ENTER_CRITICAL_REGION;
482 res = mono_gc_try_alloc_obj_nolock (vtable, size);
484 EXIT_CRITICAL_REGION;
487 EXIT_CRITICAL_REGION;
490 res = mono_gc_alloc_obj_nolock (vtable, size);
492 if (G_UNLIKELY (!res))
493 return mono_gc_out_of_memory (size);
498 mono_gc_alloc_vector (MonoVTable *vtable, size_t size, uintptr_t max_length)
502 if (!SGEN_CAN_ALIGN_UP (size))
505 #ifndef DISABLE_CRITICAL_REGION
507 ENTER_CRITICAL_REGION;
508 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
510 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
511 arr->max_length = max_length;
512 EXIT_CRITICAL_REGION;
515 EXIT_CRITICAL_REGION;
520 arr = mono_gc_alloc_obj_nolock (vtable, size);
521 if (G_UNLIKELY (!arr)) {
523 return mono_gc_out_of_memory (size);
526 arr->max_length = max_length;
534 mono_gc_alloc_array (MonoVTable *vtable, size_t size, uintptr_t max_length, uintptr_t bounds_size)
537 MonoArrayBounds *bounds;
539 if (!SGEN_CAN_ALIGN_UP (size))
542 #ifndef DISABLE_CRITICAL_REGION
544 ENTER_CRITICAL_REGION;
545 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
547 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
548 arr->max_length = max_length;
550 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
551 arr->bounds = bounds;
552 EXIT_CRITICAL_REGION;
555 EXIT_CRITICAL_REGION;
560 arr = mono_gc_alloc_obj_nolock (vtable, size);
561 if (G_UNLIKELY (!arr)) {
563 return mono_gc_out_of_memory (size);
566 arr->max_length = max_length;
568 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
569 arr->bounds = bounds;
577 mono_gc_alloc_string (MonoVTable *vtable, size_t size, gint32 len)
581 if (!SGEN_CAN_ALIGN_UP (size))
584 #ifndef DISABLE_CRITICAL_REGION
586 ENTER_CRITICAL_REGION;
587 str = mono_gc_try_alloc_obj_nolock (vtable, size);
589 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
591 EXIT_CRITICAL_REGION;
594 EXIT_CRITICAL_REGION;
599 str = mono_gc_alloc_obj_nolock (vtable, size);
600 if (G_UNLIKELY (!str)) {
602 return mono_gc_out_of_memory (size);
613 * To be used for interned strings and possibly MonoThread, reflection handles.
614 * We may want to explicitly free these objects.
617 mono_gc_alloc_pinned_obj (MonoVTable *vtable, size_t size)
621 if (!SGEN_CAN_ALIGN_UP (size))
623 size = ALIGN_UP (size);
627 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
628 /* large objects are always pinned anyway */
629 p = sgen_los_alloc_large_inner (vtable, size);
631 SGEN_ASSERT (9, vtable->klass->inited, "class %s:%s is not initialized", vtable->klass->name_space, vtable->klass->name);
632 p = major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
635 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
636 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
637 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
639 MONO_GC_MAJOR_OBJ_ALLOC_PINNED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
640 binary_protocol_alloc_pinned (p, vtable, size);
647 mono_gc_alloc_mature (MonoVTable *vtable)
650 size_t size = vtable->klass->instance_size;
652 if (!SGEN_CAN_ALIGN_UP (size))
654 size = ALIGN_UP (size);
657 res = alloc_degraded (vtable, size, TRUE);
659 if (G_UNLIKELY (vtable->klass->has_finalize))
660 mono_object_register_finalizer ((MonoObject*)res);
666 mono_gc_alloc_fixed (size_t size, void *descr)
668 /* FIXME: do a single allocation */
669 void *res = calloc (1, size);
672 if (!mono_gc_register_root (res, size, descr)) {
680 mono_gc_free_fixed (void* addr)
682 mono_gc_deregister_root (addr);
687 sgen_init_tlab_info (SgenThreadInfo* info)
689 #ifndef HAVE_KW_THREAD
690 SgenThreadInfo *__thread_info__ = info;
693 info->tlab_start_addr = &TLAB_START;
694 info->tlab_next_addr = &TLAB_NEXT;
695 info->tlab_temp_end_addr = &TLAB_TEMP_END;
696 info->tlab_real_end_addr = &TLAB_REAL_END;
698 #ifdef HAVE_KW_THREAD
699 tlab_next_addr = &tlab_next;
704 * Clear the thread local TLAB variables for all threads.
707 sgen_clear_tlabs (void)
709 SgenThreadInfo *info;
711 FOREACH_THREAD (info) {
712 /* A new TLAB will be allocated when the thread does its first allocation */
713 *info->tlab_start_addr = NULL;
714 *info->tlab_next_addr = NULL;
715 *info->tlab_temp_end_addr = NULL;
716 *info->tlab_real_end_addr = NULL;
720 static MonoMethod* alloc_method_cache [ATYPE_NUM];
722 #ifdef MANAGED_ALLOCATION
723 /* FIXME: Do this in the JIT, where specialized allocation sequences can be created
724 * for each class. This is currently not easy to do, as it is hard to generate basic
725 * blocks + branches, but it is easy with the linear IL codebase.
727 * For this to work we'd need to solve the TLAB race, first. Now we
728 * require the allocator to be in a few known methods to make sure
729 * that they are executed atomically via the restart mechanism.
732 create_allocator (int atype)
735 guint32 slowpath_branch, max_size_branch;
736 MonoMethodBuilder *mb;
738 MonoMethodSignature *csig;
739 static gboolean registered = FALSE;
740 int tlab_next_addr_var, new_next_var;
742 const char *name = NULL;
743 AllocatorWrapperInfo *info;
745 #ifdef HAVE_KW_THREAD
746 int tlab_next_addr_offset = -1;
747 int tlab_temp_end_offset = -1;
749 MONO_THREAD_VAR_OFFSET (tlab_next_addr, tlab_next_addr_offset);
750 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
752 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_NEXT_ADDR, tlab_next_addr_offset);
753 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_TEMP_END, tlab_temp_end_offset);
755 g_assert (tlab_next_addr_offset != -1);
756 g_assert (tlab_temp_end_offset != -1);
760 mono_register_jit_icall (mono_gc_alloc_obj, "mono_gc_alloc_obj", mono_create_icall_signature ("object ptr int"), FALSE);
761 mono_register_jit_icall (mono_gc_alloc_vector, "mono_gc_alloc_vector", mono_create_icall_signature ("object ptr int int"), FALSE);
762 mono_register_jit_icall (mono_gc_alloc_string, "mono_gc_alloc_string", mono_create_icall_signature ("object ptr int int32"), FALSE);
766 if (atype == ATYPE_SMALL) {
769 } else if (atype == ATYPE_NORMAL) {
772 } else if (atype == ATYPE_VECTOR) {
774 name = "AllocVector";
775 } else if (atype == ATYPE_STRING) {
777 name = "AllocString";
779 g_assert_not_reached ();
782 csig = mono_metadata_signature_alloc (mono_defaults.corlib, num_params);
783 if (atype == ATYPE_STRING) {
784 csig->ret = &mono_defaults.string_class->byval_arg;
785 csig->params [0] = &mono_defaults.int_class->byval_arg;
786 csig->params [1] = &mono_defaults.int32_class->byval_arg;
788 csig->ret = &mono_defaults.object_class->byval_arg;
789 for (i = 0; i < num_params; ++i)
790 csig->params [i] = &mono_defaults.int_class->byval_arg;
793 mb = mono_mb_new (mono_defaults.object_class, name, MONO_WRAPPER_ALLOC);
796 size_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
797 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
798 /* size = vtable->klass->instance_size; */
799 mono_mb_emit_ldarg (mb, 0);
800 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
801 mono_mb_emit_byte (mb, CEE_ADD);
802 mono_mb_emit_byte (mb, CEE_LDIND_I);
803 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, instance_size));
804 mono_mb_emit_byte (mb, CEE_ADD);
805 /* FIXME: assert instance_size stays a 4 byte integer */
806 mono_mb_emit_byte (mb, CEE_LDIND_U4);
807 mono_mb_emit_byte (mb, CEE_CONV_I);
808 mono_mb_emit_stloc (mb, size_var);
809 } else if (atype == ATYPE_VECTOR) {
810 MonoExceptionClause *clause;
811 int pos, pos_leave, pos_error;
812 MonoClass *oom_exc_class;
816 * n > MONO_ARRAY_MAX_INDEX => OutOfMemoryException
817 * n < 0 => OverflowException
819 * We can do an unsigned comparison to catch both cases, then in the error
820 * case compare signed to distinguish between them.
822 mono_mb_emit_ldarg (mb, 1);
823 mono_mb_emit_icon (mb, MONO_ARRAY_MAX_INDEX);
824 mono_mb_emit_byte (mb, CEE_CONV_U);
825 pos = mono_mb_emit_short_branch (mb, CEE_BLE_UN_S);
827 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
828 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
829 mono_mb_emit_ldarg (mb, 1);
830 mono_mb_emit_icon (mb, 0);
831 pos_error = mono_mb_emit_short_branch (mb, CEE_BLT_S);
832 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
833 mono_mb_patch_short_branch (mb, pos_error);
834 mono_mb_emit_exception (mb, "OverflowException", NULL);
836 mono_mb_patch_short_branch (mb, pos);
838 clause = mono_image_alloc0 (mono_defaults.corlib, sizeof (MonoExceptionClause));
839 clause->try_offset = mono_mb_get_label (mb);
841 /* vtable->klass->sizes.element_size */
842 mono_mb_emit_ldarg (mb, 0);
843 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
844 mono_mb_emit_byte (mb, CEE_ADD);
845 mono_mb_emit_byte (mb, CEE_LDIND_I);
846 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, sizes.element_size));
847 mono_mb_emit_byte (mb, CEE_ADD);
848 mono_mb_emit_byte (mb, CEE_LDIND_U4);
849 mono_mb_emit_byte (mb, CEE_CONV_I);
852 mono_mb_emit_ldarg (mb, 1);
853 mono_mb_emit_byte (mb, CEE_MUL_OVF_UN);
854 /* + sizeof (MonoArray) */
855 mono_mb_emit_icon (mb, sizeof (MonoArray));
856 mono_mb_emit_byte (mb, CEE_ADD_OVF_UN);
857 mono_mb_emit_stloc (mb, size_var);
859 pos_leave = mono_mb_emit_branch (mb, CEE_LEAVE);
862 clause->flags = MONO_EXCEPTION_CLAUSE_NONE;
863 clause->try_len = mono_mb_get_pos (mb) - clause->try_offset;
864 clause->data.catch_class = mono_class_from_name (mono_defaults.corlib,
865 "System", "OverflowException");
866 g_assert (clause->data.catch_class);
867 clause->handler_offset = mono_mb_get_label (mb);
869 oom_exc_class = mono_class_from_name (mono_defaults.corlib,
870 "System", "OutOfMemoryException");
871 g_assert (oom_exc_class);
872 ctor = mono_class_get_method_from_name (oom_exc_class, ".ctor", 0);
875 mono_mb_emit_byte (mb, CEE_POP);
876 mono_mb_emit_op (mb, CEE_NEWOBJ, ctor);
877 mono_mb_emit_byte (mb, CEE_THROW);
879 clause->handler_len = mono_mb_get_pos (mb) - clause->handler_offset;
880 mono_mb_set_clauses (mb, 1, clause);
881 mono_mb_patch_branch (mb, pos_leave);
883 } else if (atype == ATYPE_STRING) {
887 * a string allocator method takes the args: (vtable, len)
889 * bytes = sizeof (MonoString) + ((len + 1) * 2)
893 * bytes <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
897 * sizeof (MonoString) + ((len + 1) * 2) <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
898 * len <= (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1
900 mono_mb_emit_ldarg (mb, 1);
901 mono_mb_emit_icon (mb, (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1);
902 pos = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
904 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
905 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
906 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
907 mono_mb_patch_short_branch (mb, pos);
909 mono_mb_emit_ldarg (mb, 1);
910 mono_mb_emit_icon (mb, 1);
911 mono_mb_emit_byte (mb, MONO_CEE_SHL);
912 //WE manually fold the above + 2 here
913 mono_mb_emit_icon (mb, sizeof (MonoString) + 2);
914 mono_mb_emit_byte (mb, CEE_ADD);
915 mono_mb_emit_stloc (mb, size_var);
917 g_assert_not_reached ();
920 /* size += ALLOC_ALIGN - 1; */
921 mono_mb_emit_ldloc (mb, size_var);
922 mono_mb_emit_icon (mb, ALLOC_ALIGN - 1);
923 mono_mb_emit_byte (mb, CEE_ADD);
924 /* size &= ~(ALLOC_ALIGN - 1); */
925 mono_mb_emit_icon (mb, ~(ALLOC_ALIGN - 1));
926 mono_mb_emit_byte (mb, CEE_AND);
927 mono_mb_emit_stloc (mb, size_var);
929 /* if (size > MAX_SMALL_OBJ_SIZE) goto slowpath */
930 if (atype != ATYPE_SMALL) {
931 mono_mb_emit_ldloc (mb, size_var);
932 mono_mb_emit_icon (mb, MAX_SMALL_OBJ_SIZE);
933 max_size_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
937 * We need to modify tlab_next, but the JIT only supports reading, so we read
938 * another tls var holding its address instead.
941 /* tlab_next_addr (local) = tlab_next_addr (TLS var) */
942 tlab_next_addr_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
943 EMIT_TLS_ACCESS (mb, tlab_next_addr, TLS_KEY_SGEN_TLAB_NEXT_ADDR);
944 mono_mb_emit_stloc (mb, tlab_next_addr_var);
946 /* p = (void**)tlab_next; */
947 p_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
948 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
949 mono_mb_emit_byte (mb, CEE_LDIND_I);
950 mono_mb_emit_stloc (mb, p_var);
952 /* new_next = (char*)p + size; */
953 new_next_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
954 mono_mb_emit_ldloc (mb, p_var);
955 mono_mb_emit_ldloc (mb, size_var);
956 mono_mb_emit_byte (mb, CEE_CONV_I);
957 mono_mb_emit_byte (mb, CEE_ADD);
958 mono_mb_emit_stloc (mb, new_next_var);
960 /* if (G_LIKELY (new_next < tlab_temp_end)) */
961 mono_mb_emit_ldloc (mb, new_next_var);
962 EMIT_TLS_ACCESS (mb, tlab_temp_end, TLS_KEY_SGEN_TLAB_TEMP_END);
963 slowpath_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
966 if (atype != ATYPE_SMALL)
967 mono_mb_patch_short_branch (mb, max_size_branch);
969 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
970 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
972 /* FIXME: mono_gc_alloc_obj takes a 'size_t' as an argument, not an int32 */
973 mono_mb_emit_ldarg (mb, 0);
974 mono_mb_emit_ldloc (mb, size_var);
975 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
976 mono_mb_emit_icall (mb, mono_gc_alloc_obj);
977 } else if (atype == ATYPE_VECTOR) {
978 mono_mb_emit_ldarg (mb, 1);
979 mono_mb_emit_icall (mb, mono_gc_alloc_vector);
980 } else if (atype == ATYPE_STRING) {
981 mono_mb_emit_ldarg (mb, 1);
982 mono_mb_emit_icall (mb, mono_gc_alloc_string);
984 g_assert_not_reached ();
986 mono_mb_emit_byte (mb, CEE_RET);
989 mono_mb_patch_short_branch (mb, slowpath_branch);
991 /* FIXME: Memory barrier */
993 /* tlab_next = new_next */
994 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
995 mono_mb_emit_ldloc (mb, new_next_var);
996 mono_mb_emit_byte (mb, CEE_STIND_I);
998 /*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. */
999 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1000 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, StoreStoreBarrier);
1003 mono_mb_emit_ldloc (mb, p_var);
1004 mono_mb_emit_ldarg (mb, 0);
1005 mono_mb_emit_byte (mb, CEE_STIND_I);
1007 if (atype == ATYPE_VECTOR) {
1008 /* arr->max_length = max_length; */
1009 mono_mb_emit_ldloc (mb, p_var);
1010 mono_mb_emit_ldflda (mb, G_STRUCT_OFFSET (MonoArray, max_length));
1011 mono_mb_emit_ldarg (mb, 1);
1012 #ifdef MONO_BIG_ARRAYS
1013 mono_mb_emit_byte (mb, CEE_STIND_I);
1015 mono_mb_emit_byte (mb, CEE_STIND_I4);
1017 } else if (atype == ATYPE_STRING) {
1018 /* need to set length and clear the last char */
1019 /* s->length = len; */
1020 mono_mb_emit_ldloc (mb, p_var);
1021 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, length));
1022 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1023 mono_mb_emit_ldarg (mb, 1);
1024 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
1025 /* s->chars [len] = 0; */
1026 mono_mb_emit_ldloc (mb, p_var);
1027 mono_mb_emit_ldloc (mb, size_var);
1028 mono_mb_emit_icon (mb, 2);
1029 mono_mb_emit_byte (mb, MONO_CEE_SUB);
1030 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1031 mono_mb_emit_icon (mb, 0);
1032 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
1036 We must make sure both vtable and max_length are globaly visible before returning to managed land.
1038 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1039 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, StoreStoreBarrier);
1042 mono_mb_emit_ldloc (mb, p_var);
1043 mono_mb_emit_byte (mb, CEE_RET);
1046 res = mono_mb_create_method (mb, csig, 8);
1048 mono_method_get_header (res)->init_locals = FALSE;
1050 info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
1051 info->gc_name = "sgen";
1052 info->alloc_type = atype;
1053 mono_marshal_set_wrapper_info (res, info);
1060 * Generate an allocator method implementing the fast path of mono_gc_alloc_obj ().
1061 * The signature of the called method is:
1062 * object allocate (MonoVTable *vtable)
1065 mono_gc_get_managed_allocator (MonoClass *klass, gboolean for_box)
1067 #ifdef MANAGED_ALLOCATION
1069 #ifdef HAVE_KW_THREAD
1070 int tlab_next_offset = -1;
1071 int tlab_temp_end_offset = -1;
1072 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1073 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1075 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1078 if (collect_before_allocs)
1080 if (!mono_runtime_has_tls_get ())
1082 if (klass->instance_size > tlab_size)
1085 if (klass->has_finalize || mono_class_is_marshalbyref (klass) || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
1089 if (klass->byval_arg.type == MONO_TYPE_STRING)
1090 return mono_gc_get_managed_allocator_by_type (ATYPE_STRING);
1091 /* Generic classes have dynamic field and can go above MAX_SMALL_OBJ_SIZE. */
1092 if (ALIGN_TO (klass->instance_size, ALLOC_ALIGN) < MAX_SMALL_OBJ_SIZE && !mono_class_is_open_constructed_type (&klass->byval_arg))
1093 return mono_gc_get_managed_allocator_by_type (ATYPE_SMALL);
1095 return mono_gc_get_managed_allocator_by_type (ATYPE_NORMAL);
1102 mono_gc_get_managed_array_allocator (MonoClass *klass)
1104 #ifdef MANAGED_ALLOCATION
1105 #ifdef HAVE_KW_THREAD
1106 int tlab_next_offset = -1;
1107 int tlab_temp_end_offset = -1;
1108 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1109 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1111 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1115 if (klass->rank != 1)
1117 if (!mono_runtime_has_tls_get ())
1119 if (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS)
1121 if (has_per_allocation_action)
1123 g_assert (!mono_class_has_finalizer (klass) && !mono_class_is_marshalbyref (klass));
1125 return mono_gc_get_managed_allocator_by_type (ATYPE_VECTOR);
1132 sgen_set_use_managed_allocator (gboolean flag)
1134 use_managed_allocator = flag;
1138 mono_gc_get_managed_allocator_by_type (int atype)
1140 #ifdef MANAGED_ALLOCATION
1143 if (!use_managed_allocator)
1146 if (!mono_runtime_has_tls_get ())
1149 res = alloc_method_cache [atype];
1153 res = create_allocator (atype);
1155 if (alloc_method_cache [atype]) {
1156 mono_free_method (res);
1157 res = alloc_method_cache [atype];
1159 mono_memory_barrier ();
1160 alloc_method_cache [atype] = res;
1171 mono_gc_get_managed_allocator_types (void)
1177 sgen_is_managed_allocator (MonoMethod *method)
1181 for (i = 0; i < ATYPE_NUM; ++i)
1182 if (method == alloc_method_cache [i])
1188 sgen_has_managed_allocator (void)
1192 for (i = 0; i < ATYPE_NUM; ++i)
1193 if (alloc_method_cache [i])
1198 #ifdef HEAVY_STATISTICS
1200 sgen_alloc_init_heavy_stats (void)
1202 mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced);
1203 mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced);
1204 mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_los);
1208 #endif /*HAVE_SGEN_GC*/