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 */
193 HEAVY_STAT (++stat_objects_alloced);
194 if (size <= SGEN_MAX_SMALL_OBJ_SIZE)
195 HEAVY_STAT (stat_bytes_alloced += size);
197 HEAVY_STAT (stat_bytes_alloced_los += size);
199 size = ALIGN_UP (size);
201 g_assert (vtable->gc_descr);
203 if (G_UNLIKELY (has_per_allocation_action)) {
204 static int alloc_count;
205 int current_alloc = InterlockedIncrement (&alloc_count);
207 if (collect_before_allocs) {
208 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
209 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
210 if (!degraded_mode && sgen_can_alloc_size (size) && size <= SGEN_MAX_SMALL_OBJ_SIZE) {
212 g_assert_not_reached ();
215 } else if (verify_before_allocs) {
216 if ((current_alloc % verify_before_allocs) == 0)
217 sgen_check_whole_heap_stw ();
222 * We must already have the lock here instead of after the
223 * fast path because we might be interrupted in the fast path
224 * (after confirming that new_next < TLAB_TEMP_END) by the GC,
225 * and we'll end up allocating an object in a fragment which
226 * no longer belongs to us.
228 * The managed allocator does not do this, but it's treated
229 * specially by the world-stopping code.
232 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
233 p = sgen_los_alloc_large_inner (vtable, size);
235 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
237 p = (void**)TLAB_NEXT;
238 /* FIXME: handle overflow */
239 new_next = (char*)p + size;
240 TLAB_NEXT = new_next;
242 if (G_LIKELY (new_next < TLAB_TEMP_END)) {
246 * FIXME: We might need a memory barrier here so the change to tlab_next is
247 * visible before the vtable store.
250 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
251 binary_protocol_alloc (p , vtable, size);
252 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
253 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
254 g_assert (*p == NULL);
255 mono_atomic_store_seq (p, vtable);
262 /* there are two cases: the object is too big or we run out of space in the TLAB */
263 /* we also reach here when the thread does its first allocation after a minor
264 * collection, since the tlab_ variables are initialized to NULL.
265 * there can be another case (from ORP), if we cooperate with the runtime a bit:
266 * objects that need finalizers can have the high bit set in their size
267 * so the above check fails and we can readily add the object to the queue.
268 * This avoids taking again the GC lock when registering, but this is moot when
269 * doing thread-local allocation, so it may not be a good idea.
271 if (TLAB_NEXT >= TLAB_REAL_END) {
272 int available_in_tlab;
274 * Run out of space in the TLAB. When this happens, some amount of space
275 * remains in the TLAB, but not enough to satisfy the current allocation
276 * request. Currently, we retire the TLAB in all cases, later we could
277 * keep it if the remaining space is above a treshold, and satisfy the
278 * allocation directly from the nursery.
281 /* when running in degraded mode, we continue allocing that way
282 * for a while, to decrease the number of useless nursery collections.
284 if (degraded_mode && degraded_mode < DEFAULT_NURSERY_SIZE)
285 return alloc_degraded (vtable, size, FALSE);
287 available_in_tlab = (int)(TLAB_REAL_END - TLAB_NEXT);//We'll never have tlabs > 2Gb
288 if (size > tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
289 /* Allocate directly from the nursery */
291 p = sgen_nursery_alloc (size);
293 sgen_ensure_free_space (size);
295 return alloc_degraded (vtable, size, FALSE);
297 p = sgen_nursery_alloc (size);
305 zero_tlab_if_necessary (p, size);
307 size_t alloc_size = 0;
309 SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
310 sgen_nursery_retire_region (p, available_in_tlab);
313 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
315 sgen_ensure_free_space (tlab_size);
317 return alloc_degraded (vtable, size, FALSE);
319 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
328 /* Allocate a new TLAB from the current nursery fragment */
329 TLAB_START = (char*)p;
330 TLAB_NEXT = TLAB_START;
331 TLAB_REAL_END = TLAB_START + alloc_size;
332 TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
334 zero_tlab_if_necessary (TLAB_START, alloc_size);
336 /* Allocate from the TLAB */
337 p = (void*)TLAB_NEXT;
339 sgen_set_nursery_scan_start ((char*)p);
342 /* Reached tlab_temp_end */
344 /* record the scan start so we can find pinned objects more easily */
345 sgen_set_nursery_scan_start ((char*)p);
346 /* we just bump tlab_temp_end as well */
347 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
348 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
353 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
354 binary_protocol_alloc (p, vtable, size);
355 if (G_UNLIKELY (MONO_GC_MAJOR_OBJ_ALLOC_LARGE_ENABLED ()|| MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ())) {
356 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
357 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
359 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
361 mono_atomic_store_seq (p, vtable);
368 mono_gc_try_alloc_obj_nolock (MonoVTable *vtable, size_t size)
374 size = ALIGN_UP (size);
375 SGEN_ASSERT (9, size >= sizeof (MonoObject), "Object too small");
377 g_assert (vtable->gc_descr);
378 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
381 if (G_UNLIKELY (size > tlab_size)) {
382 /* Allocate directly from the nursery */
383 p = sgen_nursery_alloc (size);
386 sgen_set_nursery_scan_start ((char*)p);
388 /*FIXME we should use weak memory ops here. Should help specially on x86. */
389 zero_tlab_if_necessary (p, size);
391 int available_in_tlab;
393 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
395 p = (void**)TLAB_NEXT;
396 /* FIXME: handle overflow */
397 new_next = (char*)p + size;
399 real_end = TLAB_REAL_END;
400 available_in_tlab = (int)(real_end - (char*)p);//We'll never have tlabs > 2Gb
402 if (G_LIKELY (new_next < real_end)) {
403 TLAB_NEXT = new_next;
405 /* Second case, we overflowed temp end */
406 if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
407 sgen_set_nursery_scan_start (new_next);
408 /* we just bump tlab_temp_end as well */
409 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
410 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
412 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
413 /* Allocate directly from the nursery */
414 p = sgen_nursery_alloc (size);
418 zero_tlab_if_necessary (p, size);
420 size_t alloc_size = 0;
422 sgen_nursery_retire_region (p, available_in_tlab);
423 new_next = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
424 p = (void**)new_next;
428 TLAB_START = (char*)new_next;
429 TLAB_NEXT = new_next + size;
430 TLAB_REAL_END = new_next + alloc_size;
431 TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
432 sgen_set_nursery_scan_start ((char*)p);
434 zero_tlab_if_necessary (new_next, alloc_size);
436 MONO_GC_NURSERY_TLAB_ALLOC ((mword)new_next, alloc_size);
440 HEAVY_STAT (++stat_objects_alloced);
441 HEAVY_STAT (stat_bytes_alloced += size);
443 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
444 binary_protocol_alloc (p, vtable, size);
445 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
446 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
447 g_assert (*p == NULL); /* FIXME disable this in non debug builds */
449 mono_atomic_store_seq (p, vtable);
455 mono_gc_alloc_obj (MonoVTable *vtable, size_t size)
460 if (!SGEN_CAN_ALIGN_UP (size))
463 #ifndef DISABLE_CRITICAL_REGION
465 if (G_UNLIKELY (has_per_allocation_action)) {
466 static int alloc_count;
467 int current_alloc = InterlockedIncrement (&alloc_count);
469 if (verify_before_allocs) {
470 if ((current_alloc % verify_before_allocs) == 0)
471 sgen_check_whole_heap_stw ();
473 if (collect_before_allocs) {
474 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
476 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
482 ENTER_CRITICAL_REGION;
483 res = mono_gc_try_alloc_obj_nolock (vtable, size);
485 EXIT_CRITICAL_REGION;
488 EXIT_CRITICAL_REGION;
491 res = mono_gc_alloc_obj_nolock (vtable, size);
493 if (G_UNLIKELY (!res))
494 return mono_gc_out_of_memory (size);
499 mono_gc_alloc_vector (MonoVTable *vtable, size_t size, uintptr_t max_length)
504 if (!SGEN_CAN_ALIGN_UP (size))
507 #ifndef DISABLE_CRITICAL_REGION
508 ENTER_CRITICAL_REGION;
509 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
511 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
512 arr->max_length = (mono_array_size_t)max_length;
513 EXIT_CRITICAL_REGION;
516 EXIT_CRITICAL_REGION;
521 arr = mono_gc_alloc_obj_nolock (vtable, size);
522 if (G_UNLIKELY (!arr)) {
524 return mono_gc_out_of_memory (size);
527 arr->max_length = (mono_array_size_t)max_length;
535 mono_gc_alloc_array (MonoVTable *vtable, size_t size, uintptr_t max_length, uintptr_t bounds_size)
538 MonoArrayBounds *bounds;
541 if (!SGEN_CAN_ALIGN_UP (size))
544 #ifndef DISABLE_CRITICAL_REGION
545 ENTER_CRITICAL_REGION;
546 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
548 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
549 arr->max_length = (mono_array_size_t)max_length;
551 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
552 arr->bounds = bounds;
553 EXIT_CRITICAL_REGION;
556 EXIT_CRITICAL_REGION;
561 arr = mono_gc_alloc_obj_nolock (vtable, size);
562 if (G_UNLIKELY (!arr)) {
564 return mono_gc_out_of_memory (size);
567 arr->max_length = (mono_array_size_t)max_length;
569 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
570 arr->bounds = bounds;
578 mono_gc_alloc_string (MonoVTable *vtable, size_t size, gint32 len)
583 if (!SGEN_CAN_ALIGN_UP (size))
586 #ifndef DISABLE_CRITICAL_REGION
587 ENTER_CRITICAL_REGION;
588 str = mono_gc_try_alloc_obj_nolock (vtable, size);
590 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
592 EXIT_CRITICAL_REGION;
595 EXIT_CRITICAL_REGION;
600 str = mono_gc_alloc_obj_nolock (vtable, size);
601 if (G_UNLIKELY (!str)) {
603 return mono_gc_out_of_memory (size);
614 * To be used for interned strings and possibly MonoThread, reflection handles.
615 * We may want to explicitly free these objects.
618 mono_gc_alloc_pinned_obj (MonoVTable *vtable, size_t size)
622 if (!SGEN_CAN_ALIGN_UP (size))
624 size = ALIGN_UP (size);
628 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
629 /* large objects are always pinned anyway */
630 p = sgen_los_alloc_large_inner (vtable, size);
632 SGEN_ASSERT (9, vtable->klass->inited, "class %s:%s is not initialized", vtable->klass->name_space, vtable->klass->name);
633 p = major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
636 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
637 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
638 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
640 MONO_GC_MAJOR_OBJ_ALLOC_PINNED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
641 binary_protocol_alloc_pinned (p, vtable, size);
648 mono_gc_alloc_mature (MonoVTable *vtable)
651 size_t size = vtable->klass->instance_size;
653 if (!SGEN_CAN_ALIGN_UP (size))
655 size = ALIGN_UP (size);
658 res = alloc_degraded (vtable, size, TRUE);
660 if (G_UNLIKELY (vtable->klass->has_finalize))
661 mono_object_register_finalizer ((MonoObject*)res);
667 mono_gc_alloc_fixed (size_t size, void *descr)
669 /* FIXME: do a single allocation */
670 void *res = calloc (1, size);
673 if (!mono_gc_register_root (res, size, descr)) {
681 mono_gc_free_fixed (void* addr)
683 mono_gc_deregister_root (addr);
688 sgen_init_tlab_info (SgenThreadInfo* info)
690 #ifndef HAVE_KW_THREAD
691 SgenThreadInfo *__thread_info__ = info;
694 info->tlab_start_addr = &TLAB_START;
695 info->tlab_next_addr = &TLAB_NEXT;
696 info->tlab_temp_end_addr = &TLAB_TEMP_END;
697 info->tlab_real_end_addr = &TLAB_REAL_END;
699 #ifdef HAVE_KW_THREAD
700 tlab_next_addr = &tlab_next;
705 * Clear the thread local TLAB variables for all threads.
708 sgen_clear_tlabs (void)
710 SgenThreadInfo *info;
712 FOREACH_THREAD (info) {
713 /* A new TLAB will be allocated when the thread does its first allocation */
714 *info->tlab_start_addr = NULL;
715 *info->tlab_next_addr = NULL;
716 *info->tlab_temp_end_addr = NULL;
717 *info->tlab_real_end_addr = NULL;
721 static MonoMethod* alloc_method_cache [ATYPE_NUM];
723 #ifdef MANAGED_ALLOCATION
724 /* FIXME: Do this in the JIT, where specialized allocation sequences can be created
725 * for each class. This is currently not easy to do, as it is hard to generate basic
726 * blocks + branches, but it is easy with the linear IL codebase.
728 * For this to work we'd need to solve the TLAB race, first. Now we
729 * require the allocator to be in a few known methods to make sure
730 * that they are executed atomically via the restart mechanism.
733 create_allocator (int atype)
736 guint32 slowpath_branch, max_size_branch;
737 MonoMethodBuilder *mb;
739 MonoMethodSignature *csig;
740 static gboolean registered = FALSE;
741 int tlab_next_addr_var, new_next_var;
743 const char *name = NULL;
744 AllocatorWrapperInfo *info;
746 #ifdef HAVE_KW_THREAD
747 int tlab_next_addr_offset = -1;
748 int tlab_temp_end_offset = -1;
750 MONO_THREAD_VAR_OFFSET (tlab_next_addr, tlab_next_addr_offset);
751 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
753 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_NEXT_ADDR, tlab_next_addr_offset);
754 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_TEMP_END, tlab_temp_end_offset);
756 g_assert (tlab_next_addr_offset != -1);
757 g_assert (tlab_temp_end_offset != -1);
761 mono_register_jit_icall (mono_gc_alloc_obj, "mono_gc_alloc_obj", mono_create_icall_signature ("object ptr int"), FALSE);
762 mono_register_jit_icall (mono_gc_alloc_vector, "mono_gc_alloc_vector", mono_create_icall_signature ("object ptr int int"), FALSE);
763 mono_register_jit_icall (mono_gc_alloc_string, "mono_gc_alloc_string", mono_create_icall_signature ("object ptr int int32"), FALSE);
767 if (atype == ATYPE_SMALL) {
770 } else if (atype == ATYPE_NORMAL) {
773 } else if (atype == ATYPE_VECTOR) {
775 name = "AllocVector";
776 } else if (atype == ATYPE_STRING) {
778 name = "AllocString";
780 g_assert_not_reached ();
783 csig = mono_metadata_signature_alloc (mono_defaults.corlib, num_params);
784 if (atype == ATYPE_STRING) {
785 csig->ret = &mono_defaults.string_class->byval_arg;
786 csig->params [0] = &mono_defaults.int_class->byval_arg;
787 csig->params [1] = &mono_defaults.int32_class->byval_arg;
789 csig->ret = &mono_defaults.object_class->byval_arg;
790 for (i = 0; i < num_params; ++i)
791 csig->params [i] = &mono_defaults.int_class->byval_arg;
794 mb = mono_mb_new (mono_defaults.object_class, name, MONO_WRAPPER_ALLOC);
797 size_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
798 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
799 /* size = vtable->klass->instance_size; */
800 mono_mb_emit_ldarg (mb, 0);
801 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
802 mono_mb_emit_byte (mb, CEE_ADD);
803 mono_mb_emit_byte (mb, CEE_LDIND_I);
804 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, instance_size));
805 mono_mb_emit_byte (mb, CEE_ADD);
806 /* FIXME: assert instance_size stays a 4 byte integer */
807 mono_mb_emit_byte (mb, CEE_LDIND_U4);
808 mono_mb_emit_byte (mb, CEE_CONV_I);
809 mono_mb_emit_stloc (mb, size_var);
810 } else if (atype == ATYPE_VECTOR) {
811 MonoExceptionClause *clause;
812 int pos, pos_leave, pos_error;
813 MonoClass *oom_exc_class;
817 * n > MONO_ARRAY_MAX_INDEX => OutOfMemoryException
818 * n < 0 => OverflowException
820 * We can do an unsigned comparison to catch both cases, then in the error
821 * case compare signed to distinguish between them.
823 mono_mb_emit_ldarg (mb, 1);
824 mono_mb_emit_icon (mb, MONO_ARRAY_MAX_INDEX);
825 mono_mb_emit_byte (mb, CEE_CONV_U);
826 pos = mono_mb_emit_short_branch (mb, CEE_BLE_UN_S);
828 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
829 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
830 mono_mb_emit_ldarg (mb, 1);
831 mono_mb_emit_icon (mb, 0);
832 pos_error = mono_mb_emit_short_branch (mb, CEE_BLT_S);
833 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
834 mono_mb_patch_short_branch (mb, pos_error);
835 mono_mb_emit_exception (mb, "OverflowException", NULL);
837 mono_mb_patch_short_branch (mb, pos);
839 clause = mono_image_alloc0 (mono_defaults.corlib, sizeof (MonoExceptionClause));
840 clause->try_offset = mono_mb_get_label (mb);
842 /* vtable->klass->sizes.element_size */
843 mono_mb_emit_ldarg (mb, 0);
844 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
845 mono_mb_emit_byte (mb, CEE_ADD);
846 mono_mb_emit_byte (mb, CEE_LDIND_I);
847 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, sizes));
848 mono_mb_emit_byte (mb, CEE_ADD);
849 mono_mb_emit_byte (mb, CEE_LDIND_U4);
850 mono_mb_emit_byte (mb, CEE_CONV_I);
853 mono_mb_emit_ldarg (mb, 1);
854 mono_mb_emit_byte (mb, CEE_MUL_OVF_UN);
855 /* + sizeof (MonoArray) */
856 mono_mb_emit_icon (mb, sizeof (MonoArray));
857 mono_mb_emit_byte (mb, CEE_ADD_OVF_UN);
858 mono_mb_emit_stloc (mb, size_var);
860 pos_leave = mono_mb_emit_branch (mb, CEE_LEAVE);
863 clause->flags = MONO_EXCEPTION_CLAUSE_NONE;
864 clause->try_len = mono_mb_get_pos (mb) - clause->try_offset;
865 clause->data.catch_class = mono_class_from_name (mono_defaults.corlib,
866 "System", "OverflowException");
867 g_assert (clause->data.catch_class);
868 clause->handler_offset = mono_mb_get_label (mb);
870 oom_exc_class = mono_class_from_name (mono_defaults.corlib,
871 "System", "OutOfMemoryException");
872 g_assert (oom_exc_class);
873 ctor = mono_class_get_method_from_name (oom_exc_class, ".ctor", 0);
876 mono_mb_emit_byte (mb, CEE_POP);
877 mono_mb_emit_op (mb, CEE_NEWOBJ, ctor);
878 mono_mb_emit_byte (mb, CEE_THROW);
880 clause->handler_len = mono_mb_get_pos (mb) - clause->handler_offset;
881 mono_mb_set_clauses (mb, 1, clause);
882 mono_mb_patch_branch (mb, pos_leave);
884 } else if (atype == ATYPE_STRING) {
888 * a string allocator method takes the args: (vtable, len)
890 * bytes = sizeof (MonoString) + ((len + 1) * 2)
894 * bytes <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
898 * sizeof (MonoString) + ((len + 1) * 2) <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
899 * len <= (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1
901 mono_mb_emit_ldarg (mb, 1);
902 mono_mb_emit_icon (mb, (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1);
903 pos = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
905 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
906 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
907 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
908 mono_mb_patch_short_branch (mb, pos);
910 mono_mb_emit_ldarg (mb, 1);
911 mono_mb_emit_icon (mb, 1);
912 mono_mb_emit_byte (mb, MONO_CEE_SHL);
913 //WE manually fold the above + 2 here
914 mono_mb_emit_icon (mb, sizeof (MonoString) + 2);
915 mono_mb_emit_byte (mb, CEE_ADD);
916 mono_mb_emit_stloc (mb, size_var);
918 g_assert_not_reached ();
921 /* size += ALLOC_ALIGN - 1; */
922 mono_mb_emit_ldloc (mb, size_var);
923 mono_mb_emit_icon (mb, ALLOC_ALIGN - 1);
924 mono_mb_emit_byte (mb, CEE_ADD);
925 /* size &= ~(ALLOC_ALIGN - 1); */
926 mono_mb_emit_icon (mb, ~(ALLOC_ALIGN - 1));
927 mono_mb_emit_byte (mb, CEE_AND);
928 mono_mb_emit_stloc (mb, size_var);
930 /* if (size > MAX_SMALL_OBJ_SIZE) goto slowpath */
931 if (atype != ATYPE_SMALL) {
932 mono_mb_emit_ldloc (mb, size_var);
933 mono_mb_emit_icon (mb, MAX_SMALL_OBJ_SIZE);
934 max_size_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
938 * We need to modify tlab_next, but the JIT only supports reading, so we read
939 * another tls var holding its address instead.
942 /* tlab_next_addr (local) = tlab_next_addr (TLS var) */
943 tlab_next_addr_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
944 EMIT_TLS_ACCESS_NEXT_ADDR (mb);
945 mono_mb_emit_stloc (mb, tlab_next_addr_var);
947 /* p = (void**)tlab_next; */
948 p_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
949 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
950 mono_mb_emit_byte (mb, CEE_LDIND_I);
951 mono_mb_emit_stloc (mb, p_var);
953 /* new_next = (char*)p + size; */
954 new_next_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
955 mono_mb_emit_ldloc (mb, p_var);
956 mono_mb_emit_ldloc (mb, size_var);
957 mono_mb_emit_byte (mb, CEE_CONV_I);
958 mono_mb_emit_byte (mb, CEE_ADD);
959 mono_mb_emit_stloc (mb, new_next_var);
961 /* if (G_LIKELY (new_next < tlab_temp_end)) */
962 mono_mb_emit_ldloc (mb, new_next_var);
963 EMIT_TLS_ACCESS_TEMP_END (mb);
964 slowpath_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
967 if (atype != ATYPE_SMALL)
968 mono_mb_patch_short_branch (mb, max_size_branch);
970 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
971 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
973 /* FIXME: mono_gc_alloc_obj takes a 'size_t' as an argument, not an int32 */
974 mono_mb_emit_ldarg (mb, 0);
975 mono_mb_emit_ldloc (mb, size_var);
976 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
977 mono_mb_emit_icall (mb, mono_gc_alloc_obj);
978 } else if (atype == ATYPE_VECTOR) {
979 mono_mb_emit_ldarg (mb, 1);
980 mono_mb_emit_icall (mb, mono_gc_alloc_vector);
981 } else if (atype == ATYPE_STRING) {
982 mono_mb_emit_ldarg (mb, 1);
983 mono_mb_emit_icall (mb, mono_gc_alloc_string);
985 g_assert_not_reached ();
987 mono_mb_emit_byte (mb, CEE_RET);
990 mono_mb_patch_short_branch (mb, slowpath_branch);
992 /* FIXME: Memory barrier */
994 /* tlab_next = new_next */
995 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
996 mono_mb_emit_ldloc (mb, new_next_var);
997 mono_mb_emit_byte (mb, CEE_STIND_I);
999 /*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. */
1000 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1001 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, (gpointer)StoreStoreBarrier);
1004 mono_mb_emit_ldloc (mb, p_var);
1005 mono_mb_emit_ldarg (mb, 0);
1006 mono_mb_emit_byte (mb, CEE_STIND_I);
1008 if (atype == ATYPE_VECTOR) {
1009 /* arr->max_length = max_length; */
1010 mono_mb_emit_ldloc (mb, p_var);
1011 mono_mb_emit_ldflda (mb, MONO_STRUCT_OFFSET (MonoArray, max_length));
1012 mono_mb_emit_ldarg (mb, 1);
1013 #ifdef MONO_BIG_ARRAYS
1014 mono_mb_emit_byte (mb, CEE_STIND_I);
1016 mono_mb_emit_byte (mb, CEE_STIND_I4);
1018 } else if (atype == ATYPE_STRING) {
1019 /* need to set length and clear the last char */
1020 /* s->length = len; */
1021 mono_mb_emit_ldloc (mb, p_var);
1022 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoString, length));
1023 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1024 mono_mb_emit_ldarg (mb, 1);
1025 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
1026 /* s->chars [len] = 0; */
1027 mono_mb_emit_ldloc (mb, p_var);
1028 mono_mb_emit_ldloc (mb, size_var);
1029 mono_mb_emit_icon (mb, 2);
1030 mono_mb_emit_byte (mb, MONO_CEE_SUB);
1031 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1032 mono_mb_emit_icon (mb, 0);
1033 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
1037 We must make sure both vtable and max_length are globaly visible before returning to managed land.
1039 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1040 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, (gpointer)StoreStoreBarrier);
1043 mono_mb_emit_ldloc (mb, p_var);
1044 mono_mb_emit_byte (mb, CEE_RET);
1047 res = mono_mb_create_method (mb, csig, 8);
1049 mono_method_get_header (res)->init_locals = FALSE;
1051 info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
1052 info->gc_name = "sgen";
1053 info->alloc_type = atype;
1054 mono_marshal_set_wrapper_info (res, info);
1061 * Generate an allocator method implementing the fast path of mono_gc_alloc_obj ().
1062 * The signature of the called method is:
1063 * object allocate (MonoVTable *vtable)
1066 mono_gc_get_managed_allocator (MonoClass *klass, gboolean for_box)
1068 #ifdef MANAGED_ALLOCATION
1070 #ifdef HAVE_KW_THREAD
1071 int tlab_next_offset = -1;
1072 int tlab_temp_end_offset = -1;
1073 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1074 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1076 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1079 if (collect_before_allocs)
1081 if (!mono_runtime_has_tls_get ())
1083 if (klass->instance_size > tlab_size)
1086 if (klass->has_finalize || mono_class_is_marshalbyref (klass) || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
1090 if (klass->byval_arg.type == MONO_TYPE_STRING)
1091 return mono_gc_get_managed_allocator_by_type (ATYPE_STRING);
1092 /* Generic classes have dynamic field and can go above MAX_SMALL_OBJ_SIZE. */
1093 if (ALIGN_TO (klass->instance_size, ALLOC_ALIGN) < MAX_SMALL_OBJ_SIZE && !mono_class_is_open_constructed_type (&klass->byval_arg))
1094 return mono_gc_get_managed_allocator_by_type (ATYPE_SMALL);
1096 return mono_gc_get_managed_allocator_by_type (ATYPE_NORMAL);
1103 mono_gc_get_managed_array_allocator (MonoClass *klass)
1105 #ifdef MANAGED_ALLOCATION
1106 #ifdef HAVE_KW_THREAD
1107 int tlab_next_offset = -1;
1108 int tlab_temp_end_offset = -1;
1109 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1110 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1112 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1116 if (klass->rank != 1)
1118 if (!mono_runtime_has_tls_get ())
1120 if (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS)
1122 if (has_per_allocation_action)
1124 g_assert (!mono_class_has_finalizer (klass) && !mono_class_is_marshalbyref (klass));
1126 return mono_gc_get_managed_allocator_by_type (ATYPE_VECTOR);
1133 sgen_set_use_managed_allocator (gboolean flag)
1135 use_managed_allocator = flag;
1139 mono_gc_get_managed_allocator_by_type (int atype)
1141 #ifdef MANAGED_ALLOCATION
1144 if (!use_managed_allocator)
1147 if (!mono_runtime_has_tls_get ())
1150 res = alloc_method_cache [atype];
1154 res = create_allocator (atype);
1156 if (alloc_method_cache [atype]) {
1157 mono_free_method (res);
1158 res = alloc_method_cache [atype];
1160 mono_memory_barrier ();
1161 alloc_method_cache [atype] = res;
1172 mono_gc_get_managed_allocator_types (void)
1178 sgen_is_managed_allocator (MonoMethod *method)
1182 for (i = 0; i < ATYPE_NUM; ++i)
1183 if (method == alloc_method_cache [i])
1189 sgen_has_managed_allocator (void)
1193 for (i = 0; i < ATYPE_NUM; ++i)
1194 if (alloc_method_cache [i])
1199 #ifdef HEAVY_STATISTICS
1201 sgen_alloc_init_heavy_stats (void)
1203 mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced);
1204 mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced);
1205 mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_los);
1209 #endif /*HAVE_SGEN_GC*/