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 */
190 SgenThreadInfo *__thread_info__;
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 = TLAB_REAL_END - TLAB_NEXT;
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)
372 SgenThreadInfo *__thread_info__;
375 size = ALIGN_UP (size);
376 SGEN_ASSERT (9, size >= sizeof (MonoObject), "Object too small");
378 g_assert (vtable->gc_descr);
379 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
382 if (G_UNLIKELY (size > tlab_size)) {
383 /* Allocate directly from the nursery */
384 p = sgen_nursery_alloc (size);
387 sgen_set_nursery_scan_start ((char*)p);
389 /*FIXME we should use weak memory ops here. Should help specially on x86. */
390 zero_tlab_if_necessary (p, size);
392 int available_in_tlab;
394 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
396 p = (void**)TLAB_NEXT;
397 /* FIXME: handle overflow */
398 new_next = (char*)p + size;
400 real_end = TLAB_REAL_END;
401 available_in_tlab = real_end - (char*)p;
403 if (G_LIKELY (new_next < real_end)) {
404 TLAB_NEXT = new_next;
406 /* Second case, we overflowed temp end */
407 if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
408 sgen_set_nursery_scan_start (new_next);
409 /* we just bump tlab_temp_end as well */
410 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
411 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
413 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
414 /* Allocate directly from the nursery */
415 p = sgen_nursery_alloc (size);
419 zero_tlab_if_necessary (p, size);
421 size_t alloc_size = 0;
423 sgen_nursery_retire_region (p, available_in_tlab);
424 new_next = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
425 p = (void**)new_next;
429 TLAB_START = (char*)new_next;
430 TLAB_NEXT = new_next + size;
431 TLAB_REAL_END = new_next + alloc_size;
432 TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
433 sgen_set_nursery_scan_start ((char*)p);
435 zero_tlab_if_necessary (new_next, alloc_size);
437 MONO_GC_NURSERY_TLAB_ALLOC ((mword)new_next, alloc_size);
441 HEAVY_STAT (++stat_objects_alloced);
442 HEAVY_STAT (stat_bytes_alloced += size);
444 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
445 binary_protocol_alloc (p, vtable, size);
446 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
447 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
448 g_assert (*p == NULL); /* FIXME disable this in non debug builds */
450 mono_atomic_store_seq (p, vtable);
456 mono_gc_alloc_obj (MonoVTable *vtable, size_t size)
459 SgenThreadInfo *__thread_info__;
461 if (!SGEN_CAN_ALIGN_UP (size))
464 #ifndef DISABLE_CRITICAL_REGION
467 if (G_UNLIKELY (has_per_allocation_action)) {
468 static int alloc_count;
469 int current_alloc = InterlockedIncrement (&alloc_count);
471 if (verify_before_allocs) {
472 if ((current_alloc % verify_before_allocs) == 0)
473 sgen_check_whole_heap_stw ();
475 if (collect_before_allocs) {
476 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
478 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
484 ENTER_CRITICAL_REGION;
485 res = mono_gc_try_alloc_obj_nolock (vtable, size);
487 EXIT_CRITICAL_REGION;
490 EXIT_CRITICAL_REGION;
493 res = mono_gc_alloc_obj_nolock (vtable, size);
495 if (G_UNLIKELY (!res))
496 return mono_gc_out_of_memory (size);
501 mono_gc_alloc_vector (MonoVTable *vtable, size_t size, uintptr_t max_length)
504 SgenThreadInfo *__thread_info__;
506 if (!SGEN_CAN_ALIGN_UP (size))
509 #ifndef DISABLE_CRITICAL_REGION
511 ENTER_CRITICAL_REGION;
512 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
514 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
515 arr->max_length = max_length;
516 EXIT_CRITICAL_REGION;
519 EXIT_CRITICAL_REGION;
524 arr = mono_gc_alloc_obj_nolock (vtable, size);
525 if (G_UNLIKELY (!arr)) {
527 return mono_gc_out_of_memory (size);
530 arr->max_length = max_length;
538 mono_gc_alloc_array (MonoVTable *vtable, size_t size, uintptr_t max_length, uintptr_t bounds_size)
541 MonoArrayBounds *bounds;
542 SgenThreadInfo *__thread_info__;
544 if (!SGEN_CAN_ALIGN_UP (size))
547 #ifndef DISABLE_CRITICAL_REGION
549 ENTER_CRITICAL_REGION;
550 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
552 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
553 arr->max_length = max_length;
555 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
556 arr->bounds = bounds;
557 EXIT_CRITICAL_REGION;
560 EXIT_CRITICAL_REGION;
565 arr = mono_gc_alloc_obj_nolock (vtable, size);
566 if (G_UNLIKELY (!arr)) {
568 return mono_gc_out_of_memory (size);
571 arr->max_length = max_length;
573 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
574 arr->bounds = bounds;
582 mono_gc_alloc_string (MonoVTable *vtable, size_t size, gint32 len)
585 SgenThreadInfo *__thread_info__;
586 if (!SGEN_CAN_ALIGN_UP (size))
589 #ifndef DISABLE_CRITICAL_REGION
591 ENTER_CRITICAL_REGION;
592 str = mono_gc_try_alloc_obj_nolock (vtable, size);
594 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
596 EXIT_CRITICAL_REGION;
599 EXIT_CRITICAL_REGION;
604 str = mono_gc_alloc_obj_nolock (vtable, size);
605 if (G_UNLIKELY (!str)) {
607 return mono_gc_out_of_memory (size);
618 * To be used for interned strings and possibly MonoThread, reflection handles.
619 * We may want to explicitly free these objects.
622 mono_gc_alloc_pinned_obj (MonoVTable *vtable, size_t size)
626 if (!SGEN_CAN_ALIGN_UP (size))
628 size = ALIGN_UP (size);
632 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
633 /* large objects are always pinned anyway */
634 p = sgen_los_alloc_large_inner (vtable, size);
636 SGEN_ASSERT (9, vtable->klass->inited, "class %s:%s is not initialized", vtable->klass->name_space, vtable->klass->name);
637 p = major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
640 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
641 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
642 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
644 MONO_GC_MAJOR_OBJ_ALLOC_PINNED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
645 binary_protocol_alloc_pinned (p, vtable, size);
652 mono_gc_alloc_mature (MonoVTable *vtable)
655 size_t size = vtable->klass->instance_size;
657 if (!SGEN_CAN_ALIGN_UP (size))
659 size = ALIGN_UP (size);
662 res = alloc_degraded (vtable, size, TRUE);
664 if (G_UNLIKELY (vtable->klass->has_finalize))
665 mono_object_register_finalizer ((MonoObject*)res);
671 mono_gc_alloc_fixed (size_t size, void *descr)
673 /* FIXME: do a single allocation */
674 void *res = calloc (1, size);
677 if (!mono_gc_register_root (res, size, descr)) {
685 mono_gc_free_fixed (void* addr)
687 mono_gc_deregister_root (addr);
692 sgen_init_tlab_info (SgenThreadInfo* info)
694 #ifndef HAVE_KW_THREAD
695 SgenThreadInfo *__thread_info__ = info;
698 info->tlab_start_addr = &TLAB_START;
699 info->tlab_next_addr = &TLAB_NEXT;
700 info->tlab_temp_end_addr = &TLAB_TEMP_END;
701 info->tlab_real_end_addr = &TLAB_REAL_END;
703 #ifdef HAVE_KW_THREAD
704 tlab_next_addr = &tlab_next;
709 * Clear the thread local TLAB variables for all threads.
712 sgen_clear_tlabs (void)
714 SgenThreadInfo *info;
716 FOREACH_THREAD (info) {
717 /* A new TLAB will be allocated when the thread does its first allocation */
718 *info->tlab_start_addr = NULL;
719 *info->tlab_next_addr = NULL;
720 *info->tlab_temp_end_addr = NULL;
721 *info->tlab_real_end_addr = NULL;
725 static MonoMethod* alloc_method_cache [ATYPE_NUM];
727 #ifdef MANAGED_ALLOCATION
728 /* FIXME: Do this in the JIT, where specialized allocation sequences can be created
729 * for each class. This is currently not easy to do, as it is hard to generate basic
730 * blocks + branches, but it is easy with the linear IL codebase.
732 * For this to work we'd need to solve the TLAB race, first. Now we
733 * require the allocator to be in a few known methods to make sure
734 * that they are executed atomically via the restart mechanism.
737 create_allocator (int atype)
740 guint32 slowpath_branch, max_size_branch;
741 MonoMethodBuilder *mb;
743 MonoMethodSignature *csig;
744 static gboolean registered = FALSE;
745 int tlab_next_addr_var, new_next_var;
747 const char *name = NULL;
748 AllocatorWrapperInfo *info;
750 #ifdef HAVE_KW_THREAD
751 int tlab_next_addr_offset = -1;
752 int tlab_temp_end_offset = -1;
754 MONO_THREAD_VAR_OFFSET (tlab_next_addr, tlab_next_addr_offset);
755 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
757 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_NEXT_ADDR, tlab_next_addr_offset);
758 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_TEMP_END, tlab_temp_end_offset);
760 g_assert (tlab_next_addr_offset != -1);
761 g_assert (tlab_temp_end_offset != -1);
765 mono_register_jit_icall (mono_gc_alloc_obj, "mono_gc_alloc_obj", mono_create_icall_signature ("object ptr int"), FALSE);
766 mono_register_jit_icall (mono_gc_alloc_vector, "mono_gc_alloc_vector", mono_create_icall_signature ("object ptr int int"), FALSE);
767 mono_register_jit_icall (mono_gc_alloc_string, "mono_gc_alloc_string", mono_create_icall_signature ("object ptr int int32"), FALSE);
771 if (atype == ATYPE_SMALL) {
774 } else if (atype == ATYPE_NORMAL) {
777 } else if (atype == ATYPE_VECTOR) {
779 name = "AllocVector";
780 } else if (atype == ATYPE_STRING) {
782 name = "AllocString";
784 g_assert_not_reached ();
787 csig = mono_metadata_signature_alloc (mono_defaults.corlib, num_params);
788 if (atype == ATYPE_STRING) {
789 csig->ret = &mono_defaults.string_class->byval_arg;
790 csig->params [0] = &mono_defaults.int_class->byval_arg;
791 csig->params [1] = &mono_defaults.int32_class->byval_arg;
793 csig->ret = &mono_defaults.object_class->byval_arg;
794 for (i = 0; i < num_params; ++i)
795 csig->params [i] = &mono_defaults.int_class->byval_arg;
798 mb = mono_mb_new (mono_defaults.object_class, name, MONO_WRAPPER_ALLOC);
801 size_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
802 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
803 /* size = vtable->klass->instance_size; */
804 mono_mb_emit_ldarg (mb, 0);
805 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
806 mono_mb_emit_byte (mb, CEE_ADD);
807 mono_mb_emit_byte (mb, CEE_LDIND_I);
808 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, instance_size));
809 mono_mb_emit_byte (mb, CEE_ADD);
810 /* FIXME: assert instance_size stays a 4 byte integer */
811 mono_mb_emit_byte (mb, CEE_LDIND_U4);
812 mono_mb_emit_byte (mb, CEE_CONV_I);
813 mono_mb_emit_stloc (mb, size_var);
814 } else if (atype == ATYPE_VECTOR) {
815 MonoExceptionClause *clause;
816 int pos, pos_leave, pos_error;
817 MonoClass *oom_exc_class;
821 * n > MONO_ARRAY_MAX_INDEX => OutOfMemoryException
822 * n < 0 => OverflowException
824 * We can do an unsigned comparison to catch both cases, then in the error
825 * case compare signed to distinguish between them.
827 mono_mb_emit_ldarg (mb, 1);
828 mono_mb_emit_icon (mb, MONO_ARRAY_MAX_INDEX);
829 mono_mb_emit_byte (mb, CEE_CONV_U);
830 pos = mono_mb_emit_short_branch (mb, CEE_BLE_UN_S);
832 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
833 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
834 mono_mb_emit_ldarg (mb, 1);
835 mono_mb_emit_icon (mb, 0);
836 pos_error = mono_mb_emit_short_branch (mb, CEE_BLT_S);
837 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
838 mono_mb_patch_short_branch (mb, pos_error);
839 mono_mb_emit_exception (mb, "OverflowException", NULL);
841 mono_mb_patch_short_branch (mb, pos);
843 clause = mono_image_alloc0 (mono_defaults.corlib, sizeof (MonoExceptionClause));
844 clause->try_offset = mono_mb_get_label (mb);
846 /* vtable->klass->sizes.element_size */
847 mono_mb_emit_ldarg (mb, 0);
848 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
849 mono_mb_emit_byte (mb, CEE_ADD);
850 mono_mb_emit_byte (mb, CEE_LDIND_I);
851 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, sizes.element_size));
852 mono_mb_emit_byte (mb, CEE_ADD);
853 mono_mb_emit_byte (mb, CEE_LDIND_U4);
854 mono_mb_emit_byte (mb, CEE_CONV_I);
857 mono_mb_emit_ldarg (mb, 1);
858 mono_mb_emit_byte (mb, CEE_MUL_OVF_UN);
859 /* + sizeof (MonoArray) */
860 mono_mb_emit_icon (mb, sizeof (MonoArray));
861 mono_mb_emit_byte (mb, CEE_ADD_OVF_UN);
862 mono_mb_emit_stloc (mb, size_var);
864 pos_leave = mono_mb_emit_branch (mb, CEE_LEAVE);
867 clause->flags = MONO_EXCEPTION_CLAUSE_NONE;
868 clause->try_len = mono_mb_get_pos (mb) - clause->try_offset;
869 clause->data.catch_class = mono_class_from_name (mono_defaults.corlib,
870 "System", "OverflowException");
871 g_assert (clause->data.catch_class);
872 clause->handler_offset = mono_mb_get_label (mb);
874 oom_exc_class = mono_class_from_name (mono_defaults.corlib,
875 "System", "OutOfMemoryException");
876 g_assert (oom_exc_class);
877 ctor = mono_class_get_method_from_name (oom_exc_class, ".ctor", 0);
880 mono_mb_emit_byte (mb, CEE_POP);
881 mono_mb_emit_op (mb, CEE_NEWOBJ, ctor);
882 mono_mb_emit_byte (mb, CEE_THROW);
884 clause->handler_len = mono_mb_get_pos (mb) - clause->handler_offset;
885 mono_mb_set_clauses (mb, 1, clause);
886 mono_mb_patch_branch (mb, pos_leave);
888 } else if (atype == ATYPE_STRING) {
892 * a string allocator method takes the args: (vtable, len)
894 * bytes = sizeof (MonoString) + ((len + 1) * 2)
898 * bytes <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
902 * sizeof (MonoString) + ((len + 1) * 2) <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
903 * len <= (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1
905 mono_mb_emit_ldarg (mb, 1);
906 mono_mb_emit_icon (mb, (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - sizeof (MonoString)) / 2 - 1);
907 pos = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
909 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
910 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
911 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
912 mono_mb_patch_short_branch (mb, pos);
914 mono_mb_emit_ldarg (mb, 1);
915 mono_mb_emit_icon (mb, 1);
916 mono_mb_emit_byte (mb, MONO_CEE_SHL);
917 //WE manually fold the above + 2 here
918 mono_mb_emit_icon (mb, sizeof (MonoString) + 2);
919 mono_mb_emit_byte (mb, CEE_ADD);
920 mono_mb_emit_stloc (mb, size_var);
922 g_assert_not_reached ();
925 /* size += ALLOC_ALIGN - 1; */
926 mono_mb_emit_ldloc (mb, size_var);
927 mono_mb_emit_icon (mb, ALLOC_ALIGN - 1);
928 mono_mb_emit_byte (mb, CEE_ADD);
929 /* size &= ~(ALLOC_ALIGN - 1); */
930 mono_mb_emit_icon (mb, ~(ALLOC_ALIGN - 1));
931 mono_mb_emit_byte (mb, CEE_AND);
932 mono_mb_emit_stloc (mb, size_var);
934 /* if (size > MAX_SMALL_OBJ_SIZE) goto slowpath */
935 if (atype != ATYPE_SMALL) {
936 mono_mb_emit_ldloc (mb, size_var);
937 mono_mb_emit_icon (mb, MAX_SMALL_OBJ_SIZE);
938 max_size_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
942 * We need to modify tlab_next, but the JIT only supports reading, so we read
943 * another tls var holding its address instead.
946 /* tlab_next_addr (local) = tlab_next_addr (TLS var) */
947 tlab_next_addr_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
948 EMIT_TLS_ACCESS (mb, tlab_next_addr, TLS_KEY_SGEN_TLAB_NEXT_ADDR);
949 mono_mb_emit_stloc (mb, tlab_next_addr_var);
951 /* p = (void**)tlab_next; */
952 p_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
953 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
954 mono_mb_emit_byte (mb, CEE_LDIND_I);
955 mono_mb_emit_stloc (mb, p_var);
957 /* new_next = (char*)p + size; */
958 new_next_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
959 mono_mb_emit_ldloc (mb, p_var);
960 mono_mb_emit_ldloc (mb, size_var);
961 mono_mb_emit_byte (mb, CEE_CONV_I);
962 mono_mb_emit_byte (mb, CEE_ADD);
963 mono_mb_emit_stloc (mb, new_next_var);
965 /* if (G_LIKELY (new_next < tlab_temp_end)) */
966 mono_mb_emit_ldloc (mb, new_next_var);
967 EMIT_TLS_ACCESS (mb, tlab_temp_end, TLS_KEY_SGEN_TLAB_TEMP_END);
968 slowpath_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
971 if (atype != ATYPE_SMALL)
972 mono_mb_patch_short_branch (mb, max_size_branch);
974 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
975 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
977 /* FIXME: mono_gc_alloc_obj takes a 'size_t' as an argument, not an int32 */
978 mono_mb_emit_ldarg (mb, 0);
979 mono_mb_emit_ldloc (mb, size_var);
980 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
981 mono_mb_emit_icall (mb, mono_gc_alloc_obj);
982 } else if (atype == ATYPE_VECTOR) {
983 mono_mb_emit_ldarg (mb, 1);
984 mono_mb_emit_icall (mb, mono_gc_alloc_vector);
985 } else if (atype == ATYPE_STRING) {
986 mono_mb_emit_ldarg (mb, 1);
987 mono_mb_emit_icall (mb, mono_gc_alloc_string);
989 g_assert_not_reached ();
991 mono_mb_emit_byte (mb, CEE_RET);
994 mono_mb_patch_short_branch (mb, slowpath_branch);
996 /* FIXME: Memory barrier */
998 /* tlab_next = new_next */
999 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
1000 mono_mb_emit_ldloc (mb, new_next_var);
1001 mono_mb_emit_byte (mb, CEE_STIND_I);
1003 /*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. */
1004 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1005 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, StoreStoreBarrier);
1008 mono_mb_emit_ldloc (mb, p_var);
1009 mono_mb_emit_ldarg (mb, 0);
1010 mono_mb_emit_byte (mb, CEE_STIND_I);
1012 if (atype == ATYPE_VECTOR) {
1013 /* arr->max_length = max_length; */
1014 mono_mb_emit_ldloc (mb, p_var);
1015 mono_mb_emit_ldflda (mb, G_STRUCT_OFFSET (MonoArray, max_length));
1016 mono_mb_emit_ldarg (mb, 1);
1017 #ifdef MONO_BIG_ARRAYS
1018 mono_mb_emit_byte (mb, CEE_STIND_I);
1020 mono_mb_emit_byte (mb, CEE_STIND_I4);
1022 } else if (atype == ATYPE_STRING) {
1023 /* need to set length and clear the last char */
1024 /* s->length = len; */
1025 mono_mb_emit_ldloc (mb, p_var);
1026 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, length));
1027 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1028 mono_mb_emit_ldarg (mb, 1);
1029 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
1030 /* s->chars [len] = 0; */
1031 mono_mb_emit_ldloc (mb, p_var);
1032 mono_mb_emit_ldloc (mb, size_var);
1033 mono_mb_emit_icon (mb, 2);
1034 mono_mb_emit_byte (mb, MONO_CEE_SUB);
1035 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1036 mono_mb_emit_icon (mb, 0);
1037 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
1041 We must make sure both vtable and max_length are globaly visible before returning to managed land.
1043 mono_mb_emit_byte ((mb), MONO_CUSTOM_PREFIX);
1044 mono_mb_emit_op (mb, CEE_MONO_MEMORY_BARRIER, StoreStoreBarrier);
1047 mono_mb_emit_ldloc (mb, p_var);
1048 mono_mb_emit_byte (mb, CEE_RET);
1051 res = mono_mb_create_method (mb, csig, 8);
1053 mono_method_get_header (res)->init_locals = FALSE;
1055 info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
1056 info->gc_name = "sgen";
1057 info->alloc_type = atype;
1058 mono_marshal_set_wrapper_info (res, info);
1065 * Generate an allocator method implementing the fast path of mono_gc_alloc_obj ().
1066 * The signature of the called method is:
1067 * object allocate (MonoVTable *vtable)
1070 mono_gc_get_managed_allocator (MonoClass *klass, gboolean for_box)
1072 #ifdef MANAGED_ALLOCATION
1074 #ifdef HAVE_KW_THREAD
1075 int tlab_next_offset = -1;
1076 int tlab_temp_end_offset = -1;
1077 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1078 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1080 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1083 if (collect_before_allocs)
1085 if (!mono_runtime_has_tls_get ())
1087 if (klass->instance_size > tlab_size)
1090 if (klass->has_finalize || mono_class_is_marshalbyref (klass) || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
1094 if (klass->byval_arg.type == MONO_TYPE_STRING)
1095 return mono_gc_get_managed_allocator_by_type (ATYPE_STRING);
1096 /* Generic classes have dynamic field and can go above MAX_SMALL_OBJ_SIZE. */
1097 if (ALIGN_TO (klass->instance_size, ALLOC_ALIGN) < MAX_SMALL_OBJ_SIZE && !mono_class_is_open_constructed_type (&klass->byval_arg))
1098 return mono_gc_get_managed_allocator_by_type (ATYPE_SMALL);
1100 return mono_gc_get_managed_allocator_by_type (ATYPE_NORMAL);
1107 mono_gc_get_managed_array_allocator (MonoClass *klass)
1109 #ifdef MANAGED_ALLOCATION
1110 #ifdef HAVE_KW_THREAD
1111 int tlab_next_offset = -1;
1112 int tlab_temp_end_offset = -1;
1113 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1114 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1116 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1120 if (klass->rank != 1)
1122 if (!mono_runtime_has_tls_get ())
1124 if (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS)
1126 if (has_per_allocation_action)
1128 g_assert (!mono_class_has_finalizer (klass) && !mono_class_is_marshalbyref (klass));
1130 return mono_gc_get_managed_allocator_by_type (ATYPE_VECTOR);
1137 sgen_set_use_managed_allocator (gboolean flag)
1139 use_managed_allocator = flag;
1143 mono_gc_get_managed_allocator_by_type (int atype)
1145 #ifdef MANAGED_ALLOCATION
1148 if (!use_managed_allocator)
1151 if (!mono_runtime_has_tls_get ())
1154 res = alloc_method_cache [atype];
1158 res = create_allocator (atype);
1160 if (alloc_method_cache [atype]) {
1161 mono_free_method (res);
1162 res = alloc_method_cache [atype];
1164 mono_memory_barrier ();
1165 alloc_method_cache [atype] = res;
1176 mono_gc_get_managed_allocator_types (void)
1182 sgen_is_managed_allocator (MonoMethod *method)
1186 for (i = 0; i < ATYPE_NUM; ++i)
1187 if (method == alloc_method_cache [i])
1193 sgen_has_managed_allocator (void)
1197 for (i = 0; i < ATYPE_NUM; ++i)
1198 if (alloc_method_cache [i])
1203 #ifdef HEAVY_STATISTICS
1205 sgen_alloc_init_heavy_stats (void)
1207 mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced);
1208 mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced);
1209 mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_los);
1213 #endif /*HAVE_SGEN_GC*/