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 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 guint64 stat_objects_alloced = 0;
71 static guint64 stat_bytes_alloced = 0;
72 static guint64 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 MONO_ATTR_USED;
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 < gc_stats.major_gc_count) {
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 = gc_stats.major_gc_count;
128 SGEN_ATOMIC_ADD_P (degraded_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 || nursery_clear_policy == CLEAR_AT_TLAB_CREATION_DEBUG) {
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 size_t real_size = size;
195 HEAVY_STAT (++stat_objects_alloced);
196 if (real_size <= SGEN_MAX_SMALL_OBJ_SIZE)
197 HEAVY_STAT (stat_bytes_alloced += size);
199 HEAVY_STAT (stat_bytes_alloced_los += size);
201 size = ALIGN_UP (size);
203 g_assert (vtable->gc_descr);
205 if (G_UNLIKELY (has_per_allocation_action)) {
206 static int alloc_count;
207 int current_alloc = InterlockedIncrement (&alloc_count);
209 if (collect_before_allocs) {
210 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
211 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
212 if (!degraded_mode && sgen_can_alloc_size (size) && real_size <= SGEN_MAX_SMALL_OBJ_SIZE) {
214 g_assert_not_reached ();
217 } else if (verify_before_allocs) {
218 if ((current_alloc % verify_before_allocs) == 0)
219 sgen_check_whole_heap_stw ();
224 * We must already have the lock here instead of after the
225 * fast path because we might be interrupted in the fast path
226 * (after confirming that new_next < TLAB_TEMP_END) by the GC,
227 * and we'll end up allocating an object in a fragment which
228 * no longer belongs to us.
230 * The managed allocator does not do this, but it's treated
231 * specially by the world-stopping code.
234 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE) {
235 p = sgen_los_alloc_large_inner (vtable, ALIGN_UP (real_size));
237 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
239 p = (void**)TLAB_NEXT;
240 /* FIXME: handle overflow */
241 new_next = (char*)p + size;
242 TLAB_NEXT = new_next;
244 if (G_LIKELY (new_next < TLAB_TEMP_END)) {
248 * FIXME: We might need a memory barrier here so the change to tlab_next is
249 * visible before the vtable store.
252 CANARIFY_ALLOC(p,real_size);
253 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
254 binary_protocol_alloc (p , vtable, size);
255 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
256 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
257 g_assert (*p == NULL);
258 mono_atomic_store_seq (p, vtable);
265 /* there are two cases: the object is too big or we run out of space in the TLAB */
266 /* we also reach here when the thread does its first allocation after a minor
267 * collection, since the tlab_ variables are initialized to NULL.
268 * there can be another case (from ORP), if we cooperate with the runtime a bit:
269 * objects that need finalizers can have the high bit set in their size
270 * so the above check fails and we can readily add the object to the queue.
271 * This avoids taking again the GC lock when registering, but this is moot when
272 * doing thread-local allocation, so it may not be a good idea.
274 if (TLAB_NEXT >= TLAB_REAL_END) {
275 int available_in_tlab;
277 * Run out of space in the TLAB. When this happens, some amount of space
278 * remains in the TLAB, but not enough to satisfy the current allocation
279 * request. Currently, we retire the TLAB in all cases, later we could
280 * keep it if the remaining space is above a treshold, and satisfy the
281 * allocation directly from the nursery.
284 /* when running in degraded mode, we continue allocing that way
285 * for a while, to decrease the number of useless nursery collections.
287 if (degraded_mode && degraded_mode < DEFAULT_NURSERY_SIZE)
288 return alloc_degraded (vtable, size, FALSE);
290 available_in_tlab = (int)(TLAB_REAL_END - TLAB_NEXT);//We'll never have tlabs > 2Gb
291 if (size > tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
292 /* Allocate directly from the nursery */
293 p = sgen_nursery_alloc (size);
296 * We couldn't allocate from the nursery, so we try
297 * collecting. Even after the collection, we might
298 * still not have enough memory to allocate the
299 * object. The reason will most likely be that we've
300 * run out of memory, but there is the theoretical
301 * possibility that other threads might have consumed
302 * the freed up memory ahead of us.
304 * What we do in this case is allocate degraded, i.e.,
305 * from the major heap.
307 * Ideally we'd like to detect the case of other
308 * threads allocating ahead of us and loop (if we
309 * always loop we will loop endlessly in the case of
312 sgen_ensure_free_space (real_size);
314 p = sgen_nursery_alloc (size);
317 return alloc_degraded (vtable, size, FALSE);
319 zero_tlab_if_necessary (p, size);
321 size_t alloc_size = 0;
323 SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
324 sgen_nursery_retire_region (p, available_in_tlab);
326 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
328 /* See comment above in similar case. */
329 sgen_ensure_free_space (tlab_size);
331 p = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
334 return alloc_degraded (vtable, size, FALSE);
336 /* Allocate a new TLAB from the current nursery fragment */
337 TLAB_START = (char*)p;
338 TLAB_NEXT = TLAB_START;
339 TLAB_REAL_END = TLAB_START + alloc_size;
340 TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
342 zero_tlab_if_necessary (TLAB_START, alloc_size);
344 /* Allocate from the TLAB */
345 p = (void*)TLAB_NEXT;
347 sgen_set_nursery_scan_start ((char*)p);
350 /* Reached tlab_temp_end */
352 /* record the scan start so we can find pinned objects more easily */
353 sgen_set_nursery_scan_start ((char*)p);
354 /* we just bump tlab_temp_end as well */
355 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
356 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
358 CANARIFY_ALLOC(p,real_size);
362 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
363 binary_protocol_alloc (p, vtable, size);
364 if (G_UNLIKELY (MONO_GC_MAJOR_OBJ_ALLOC_LARGE_ENABLED ()|| MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ())) {
365 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
366 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
368 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
370 mono_atomic_store_seq (p, vtable);
377 mono_gc_try_alloc_obj_nolock (MonoVTable *vtable, size_t size)
381 size_t real_size = size;
386 size = ALIGN_UP (size);
387 SGEN_ASSERT (9, real_size >= sizeof (MonoObject), "Object too small");
389 g_assert (vtable->gc_descr);
390 if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
393 if (G_UNLIKELY (size > tlab_size)) {
394 /* Allocate directly from the nursery */
395 p = sgen_nursery_alloc (size);
398 sgen_set_nursery_scan_start ((char*)p);
400 /*FIXME we should use weak memory ops here. Should help specially on x86. */
401 zero_tlab_if_necessary (p, size);
403 int available_in_tlab;
405 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
407 p = (void**)TLAB_NEXT;
408 /* FIXME: handle overflow */
409 new_next = (char*)p + size;
411 real_end = TLAB_REAL_END;
412 available_in_tlab = (int)(real_end - (char*)p);//We'll never have tlabs > 2Gb
414 if (G_LIKELY (new_next < real_end)) {
415 TLAB_NEXT = new_next;
417 /* Second case, we overflowed temp end */
418 if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
419 sgen_set_nursery_scan_start (new_next);
420 /* we just bump tlab_temp_end as well */
421 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
422 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
424 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
425 /* Allocate directly from the nursery */
426 p = sgen_nursery_alloc (size);
430 zero_tlab_if_necessary (p, size);
432 size_t alloc_size = 0;
434 sgen_nursery_retire_region (p, available_in_tlab);
435 new_next = sgen_nursery_alloc_range (tlab_size, size, &alloc_size);
436 p = (void**)new_next;
440 TLAB_START = (char*)new_next;
441 TLAB_NEXT = new_next + size;
442 TLAB_REAL_END = new_next + alloc_size;
443 TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
444 sgen_set_nursery_scan_start ((char*)p);
446 zero_tlab_if_necessary (new_next, alloc_size);
448 MONO_GC_NURSERY_TLAB_ALLOC ((mword)new_next, alloc_size);
452 HEAVY_STAT (++stat_objects_alloced);
453 HEAVY_STAT (stat_bytes_alloced += size);
455 CANARIFY_ALLOC(p,real_size);
456 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
457 binary_protocol_alloc (p, vtable, size);
458 if (G_UNLIKELY (MONO_GC_NURSERY_OBJ_ALLOC_ENABLED ()))
459 MONO_GC_NURSERY_OBJ_ALLOC ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
460 g_assert (*p == NULL); /* FIXME disable this in non debug builds */
462 mono_atomic_store_seq (p, vtable);
468 mono_gc_alloc_obj (MonoVTable *vtable, size_t size)
473 if (!SGEN_CAN_ALIGN_UP (size))
476 #ifndef DISABLE_CRITICAL_REGION
478 if (G_UNLIKELY (has_per_allocation_action)) {
479 static int alloc_count;
480 int current_alloc = InterlockedIncrement (&alloc_count);
482 if (verify_before_allocs) {
483 if ((current_alloc % verify_before_allocs) == 0)
484 sgen_check_whole_heap_stw ();
486 if (collect_before_allocs) {
487 if (((current_alloc % collect_before_allocs) == 0) && nursery_section) {
489 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE);
495 ENTER_CRITICAL_REGION;
496 res = mono_gc_try_alloc_obj_nolock (vtable, size);
498 EXIT_CRITICAL_REGION;
501 EXIT_CRITICAL_REGION;
504 res = mono_gc_alloc_obj_nolock (vtable, size);
506 if (G_UNLIKELY (!res))
507 return mono_gc_out_of_memory (size);
512 mono_gc_alloc_vector (MonoVTable *vtable, size_t size, uintptr_t max_length)
517 if (!SGEN_CAN_ALIGN_UP (size))
520 #ifndef DISABLE_CRITICAL_REGION
521 ENTER_CRITICAL_REGION;
522 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
524 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
525 arr->max_length = (mono_array_size_t)max_length;
526 EXIT_CRITICAL_REGION;
529 EXIT_CRITICAL_REGION;
534 arr = mono_gc_alloc_obj_nolock (vtable, size);
535 if (G_UNLIKELY (!arr)) {
537 return mono_gc_out_of_memory (size);
540 arr->max_length = (mono_array_size_t)max_length;
548 mono_gc_alloc_array (MonoVTable *vtable, size_t size, uintptr_t max_length, uintptr_t bounds_size)
551 MonoArrayBounds *bounds;
554 if (!SGEN_CAN_ALIGN_UP (size))
557 #ifndef DISABLE_CRITICAL_REGION
558 ENTER_CRITICAL_REGION;
559 arr = mono_gc_try_alloc_obj_nolock (vtable, size);
561 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
562 arr->max_length = (mono_array_size_t)max_length;
564 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
565 arr->bounds = bounds;
566 EXIT_CRITICAL_REGION;
569 EXIT_CRITICAL_REGION;
574 arr = mono_gc_alloc_obj_nolock (vtable, size);
575 if (G_UNLIKELY (!arr)) {
577 return mono_gc_out_of_memory (size);
580 arr->max_length = (mono_array_size_t)max_length;
582 bounds = (MonoArrayBounds*)((char*)arr + size - bounds_size);
583 arr->bounds = bounds;
591 mono_gc_alloc_string (MonoVTable *vtable, size_t size, gint32 len)
596 if (!SGEN_CAN_ALIGN_UP (size))
599 #ifndef DISABLE_CRITICAL_REGION
600 ENTER_CRITICAL_REGION;
601 str = mono_gc_try_alloc_obj_nolock (vtable, size);
603 /*This doesn't require fencing since EXIT_CRITICAL_REGION already does it for us*/
605 EXIT_CRITICAL_REGION;
608 EXIT_CRITICAL_REGION;
613 str = mono_gc_alloc_obj_nolock (vtable, size);
614 if (G_UNLIKELY (!str)) {
616 return mono_gc_out_of_memory (size);
627 * To be used for interned strings and possibly MonoThread, reflection handles.
628 * We may want to explicitly free these objects.
631 mono_gc_alloc_pinned_obj (MonoVTable *vtable, size_t size)
635 if (!SGEN_CAN_ALIGN_UP (size))
637 size = ALIGN_UP (size);
641 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
642 /* large objects are always pinned anyway */
643 p = sgen_los_alloc_large_inner (vtable, size);
645 SGEN_ASSERT (9, vtable->klass->inited, "class %s:%s is not initialized", vtable->klass->name_space, vtable->klass->name);
646 p = major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
649 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, vtable->klass->name, size);
650 if (size > SGEN_MAX_SMALL_OBJ_SIZE)
651 MONO_GC_MAJOR_OBJ_ALLOC_LARGE ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
653 MONO_GC_MAJOR_OBJ_ALLOC_PINNED ((mword)p, size, vtable->klass->name_space, vtable->klass->name);
654 binary_protocol_alloc_pinned (p, vtable, size);
661 mono_gc_alloc_mature (MonoVTable *vtable)
664 size_t size = vtable->klass->instance_size;
666 if (!SGEN_CAN_ALIGN_UP (size))
668 size = ALIGN_UP (size);
671 res = alloc_degraded (vtable, size, TRUE);
673 if (G_UNLIKELY (vtable->klass->has_finalize))
674 mono_object_register_finalizer ((MonoObject*)res);
680 mono_gc_alloc_fixed (size_t size, void *descr)
682 /* FIXME: do a single allocation */
683 void *res = calloc (1, size);
686 if (!mono_gc_register_root (res, size, descr)) {
694 mono_gc_free_fixed (void* addr)
696 mono_gc_deregister_root (addr);
701 sgen_init_tlab_info (SgenThreadInfo* info)
703 #ifndef HAVE_KW_THREAD
704 SgenThreadInfo *__thread_info__ = info;
707 info->tlab_start_addr = &TLAB_START;
708 info->tlab_next_addr = &TLAB_NEXT;
709 info->tlab_temp_end_addr = &TLAB_TEMP_END;
710 info->tlab_real_end_addr = &TLAB_REAL_END;
712 #ifdef HAVE_KW_THREAD
713 tlab_next_addr = &tlab_next;
718 * Clear the thread local TLAB variables for all threads.
721 sgen_clear_tlabs (void)
723 SgenThreadInfo *info;
725 FOREACH_THREAD (info) {
726 /* A new TLAB will be allocated when the thread does its first allocation */
727 *info->tlab_start_addr = NULL;
728 *info->tlab_next_addr = NULL;
729 *info->tlab_temp_end_addr = NULL;
730 *info->tlab_real_end_addr = NULL;
734 static MonoMethod* alloc_method_cache [ATYPE_NUM];
736 #ifdef MANAGED_ALLOCATION
737 /* FIXME: Do this in the JIT, where specialized allocation sequences can be created
738 * for each class. This is currently not easy to do, as it is hard to generate basic
739 * blocks + branches, but it is easy with the linear IL codebase.
741 * For this to work we'd need to solve the TLAB race, first. Now we
742 * require the allocator to be in a few known methods to make sure
743 * that they are executed atomically via the restart mechanism.
746 create_allocator (int atype)
749 guint32 slowpath_branch, max_size_branch;
750 MonoMethodBuilder *mb;
752 MonoMethodSignature *csig;
753 static gboolean registered = FALSE;
754 int tlab_next_addr_var, new_next_var;
756 const char *name = NULL;
757 AllocatorWrapperInfo *info;
759 #ifdef HAVE_KW_THREAD
760 int tlab_next_addr_offset = -1;
761 int tlab_temp_end_offset = -1;
763 MONO_THREAD_VAR_OFFSET (tlab_next_addr, tlab_next_addr_offset);
764 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
766 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_NEXT_ADDR, tlab_next_addr_offset);
767 mono_tls_key_set_offset (TLS_KEY_SGEN_TLAB_TEMP_END, tlab_temp_end_offset);
769 g_assert (tlab_next_addr_offset != -1);
770 g_assert (tlab_temp_end_offset != -1);
774 mono_register_jit_icall (mono_gc_alloc_obj, "mono_gc_alloc_obj", mono_create_icall_signature ("object ptr int"), FALSE);
775 mono_register_jit_icall (mono_gc_alloc_vector, "mono_gc_alloc_vector", mono_create_icall_signature ("object ptr int int"), FALSE);
776 mono_register_jit_icall (mono_gc_alloc_string, "mono_gc_alloc_string", mono_create_icall_signature ("object ptr int int32"), FALSE);
780 if (atype == ATYPE_SMALL) {
783 } else if (atype == ATYPE_NORMAL) {
786 } else if (atype == ATYPE_VECTOR) {
788 name = "AllocVector";
789 } else if (atype == ATYPE_STRING) {
791 name = "AllocString";
793 g_assert_not_reached ();
796 csig = mono_metadata_signature_alloc (mono_defaults.corlib, num_params);
797 if (atype == ATYPE_STRING) {
798 csig->ret = &mono_defaults.string_class->byval_arg;
799 csig->params [0] = &mono_defaults.int_class->byval_arg;
800 csig->params [1] = &mono_defaults.int32_class->byval_arg;
802 csig->ret = &mono_defaults.object_class->byval_arg;
803 for (i = 0; i < num_params; ++i)
804 csig->params [i] = &mono_defaults.int_class->byval_arg;
807 mb = mono_mb_new (mono_defaults.object_class, name, MONO_WRAPPER_ALLOC);
810 size_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
811 if (atype == ATYPE_SMALL) {
812 /* size_var = size_arg */
813 mono_mb_emit_ldarg (mb, 1);
814 mono_mb_emit_stloc (mb, size_var);
815 } else if (atype == ATYPE_NORMAL) {
816 /* size = vtable->klass->instance_size; */
817 mono_mb_emit_ldarg (mb, 0);
818 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
819 mono_mb_emit_byte (mb, CEE_ADD);
820 mono_mb_emit_byte (mb, CEE_LDIND_I);
821 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, instance_size));
822 mono_mb_emit_byte (mb, CEE_ADD);
823 /* FIXME: assert instance_size stays a 4 byte integer */
824 mono_mb_emit_byte (mb, CEE_LDIND_U4);
825 mono_mb_emit_byte (mb, CEE_CONV_I);
826 mono_mb_emit_stloc (mb, size_var);
827 } else if (atype == ATYPE_VECTOR) {
828 MonoExceptionClause *clause;
829 int pos, pos_leave, pos_error;
830 MonoClass *oom_exc_class;
834 * n > MONO_ARRAY_MAX_INDEX => OutOfMemoryException
835 * n < 0 => OverflowException
837 * We can do an unsigned comparison to catch both cases, then in the error
838 * case compare signed to distinguish between them.
840 mono_mb_emit_ldarg (mb, 1);
841 mono_mb_emit_icon (mb, MONO_ARRAY_MAX_INDEX);
842 mono_mb_emit_byte (mb, CEE_CONV_U);
843 pos = mono_mb_emit_short_branch (mb, CEE_BLE_UN_S);
845 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
846 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
847 mono_mb_emit_ldarg (mb, 1);
848 mono_mb_emit_icon (mb, 0);
849 pos_error = mono_mb_emit_short_branch (mb, CEE_BLT_S);
850 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
851 mono_mb_patch_short_branch (mb, pos_error);
852 mono_mb_emit_exception (mb, "OverflowException", NULL);
854 mono_mb_patch_short_branch (mb, pos);
856 clause = mono_image_alloc0 (mono_defaults.corlib, sizeof (MonoExceptionClause));
857 clause->try_offset = mono_mb_get_label (mb);
859 /* vtable->klass->sizes.element_size */
860 mono_mb_emit_ldarg (mb, 0);
861 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoVTable, klass));
862 mono_mb_emit_byte (mb, CEE_ADD);
863 mono_mb_emit_byte (mb, CEE_LDIND_I);
864 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoClass, sizes));
865 mono_mb_emit_byte (mb, CEE_ADD);
866 mono_mb_emit_byte (mb, CEE_LDIND_U4);
867 mono_mb_emit_byte (mb, CEE_CONV_I);
870 mono_mb_emit_ldarg (mb, 1);
871 mono_mb_emit_byte (mb, CEE_MUL_OVF_UN);
872 /* + sizeof (MonoArray) */
873 mono_mb_emit_icon (mb, sizeof (MonoArray));
874 mono_mb_emit_byte (mb, CEE_ADD_OVF_UN);
875 mono_mb_emit_stloc (mb, size_var);
877 pos_leave = mono_mb_emit_branch (mb, CEE_LEAVE);
880 clause->flags = MONO_EXCEPTION_CLAUSE_NONE;
881 clause->try_len = mono_mb_get_pos (mb) - clause->try_offset;
882 clause->data.catch_class = mono_class_from_name (mono_defaults.corlib,
883 "System", "OverflowException");
884 g_assert (clause->data.catch_class);
885 clause->handler_offset = mono_mb_get_label (mb);
887 oom_exc_class = mono_class_from_name (mono_defaults.corlib,
888 "System", "OutOfMemoryException");
889 g_assert (oom_exc_class);
890 ctor = mono_class_get_method_from_name (oom_exc_class, ".ctor", 0);
893 mono_mb_emit_byte (mb, CEE_POP);
894 mono_mb_emit_op (mb, CEE_NEWOBJ, ctor);
895 mono_mb_emit_byte (mb, CEE_THROW);
897 clause->handler_len = mono_mb_get_pos (mb) - clause->handler_offset;
898 mono_mb_set_clauses (mb, 1, clause);
899 mono_mb_patch_branch (mb, pos_leave);
901 } else if (atype == ATYPE_STRING) {
905 * a string allocator method takes the args: (vtable, len)
907 * bytes = offsetof (MonoString, chars) + ((len + 1) * 2)
911 * bytes <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
915 * offsetof (MonoString, chars) + ((len + 1) * 2) <= INT32_MAX - (SGEN_ALLOC_ALIGN - 1)
916 * len <= (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - offsetof (MonoString, chars)) / 2 - 1
918 mono_mb_emit_ldarg (mb, 1);
919 mono_mb_emit_icon (mb, (INT32_MAX - (SGEN_ALLOC_ALIGN - 1) - MONO_STRUCT_OFFSET (MonoString, chars)) / 2 - 1);
920 pos = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
922 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
923 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
924 mono_mb_emit_exception (mb, "OutOfMemoryException", NULL);
925 mono_mb_patch_short_branch (mb, pos);
927 mono_mb_emit_ldarg (mb, 1);
928 mono_mb_emit_icon (mb, 1);
929 mono_mb_emit_byte (mb, MONO_CEE_SHL);
930 //WE manually fold the above + 2 here
931 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoString, chars) + 2);
932 mono_mb_emit_byte (mb, CEE_ADD);
933 mono_mb_emit_stloc (mb, size_var);
935 g_assert_not_reached ();
938 if (atype != ATYPE_SMALL) {
939 /* size += ALLOC_ALIGN - 1; */
940 mono_mb_emit_ldloc (mb, size_var);
941 mono_mb_emit_icon (mb, ALLOC_ALIGN - 1);
942 mono_mb_emit_byte (mb, CEE_ADD);
943 /* size &= ~(ALLOC_ALIGN - 1); */
944 mono_mb_emit_icon (mb, ~(ALLOC_ALIGN - 1));
945 mono_mb_emit_byte (mb, CEE_AND);
946 mono_mb_emit_stloc (mb, size_var);
949 /* if (size > MAX_SMALL_OBJ_SIZE) goto slowpath */
950 if (atype != ATYPE_SMALL) {
951 mono_mb_emit_ldloc (mb, size_var);
952 mono_mb_emit_icon (mb, MAX_SMALL_OBJ_SIZE);
953 max_size_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
957 * We need to modify tlab_next, but the JIT only supports reading, so we read
958 * another tls var holding its address instead.
961 /* tlab_next_addr (local) = tlab_next_addr (TLS var) */
962 tlab_next_addr_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
963 EMIT_TLS_ACCESS_NEXT_ADDR (mb);
964 mono_mb_emit_stloc (mb, tlab_next_addr_var);
966 /* p = (void**)tlab_next; */
967 p_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
968 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
969 mono_mb_emit_byte (mb, CEE_LDIND_I);
970 mono_mb_emit_stloc (mb, p_var);
972 /* new_next = (char*)p + size; */
973 new_next_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
974 mono_mb_emit_ldloc (mb, p_var);
975 mono_mb_emit_ldloc (mb, size_var);
976 mono_mb_emit_byte (mb, CEE_CONV_I);
977 mono_mb_emit_byte (mb, CEE_ADD);
978 mono_mb_emit_stloc (mb, new_next_var);
980 /* if (G_LIKELY (new_next < tlab_temp_end)) */
981 mono_mb_emit_ldloc (mb, new_next_var);
982 EMIT_TLS_ACCESS_TEMP_END (mb);
983 slowpath_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
986 if (atype != ATYPE_SMALL)
987 mono_mb_patch_short_branch (mb, max_size_branch);
989 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
990 mono_mb_emit_byte (mb, CEE_MONO_NOT_TAKEN);
992 /* FIXME: mono_gc_alloc_obj takes a 'size_t' as an argument, not an int32 */
993 mono_mb_emit_ldarg (mb, 0);
994 mono_mb_emit_ldloc (mb, size_var);
995 if (atype == ATYPE_NORMAL || atype == ATYPE_SMALL) {
996 mono_mb_emit_icall (mb, mono_gc_alloc_obj);
997 } else if (atype == ATYPE_VECTOR) {
998 mono_mb_emit_ldarg (mb, 1);
999 mono_mb_emit_icall (mb, mono_gc_alloc_vector);
1000 } else if (atype == ATYPE_STRING) {
1001 mono_mb_emit_ldarg (mb, 1);
1002 mono_mb_emit_icall (mb, mono_gc_alloc_string);
1004 g_assert_not_reached ();
1006 mono_mb_emit_byte (mb, CEE_RET);
1009 mono_mb_patch_short_branch (mb, slowpath_branch);
1011 /* FIXME: Memory barrier */
1013 /* tlab_next = new_next */
1014 mono_mb_emit_ldloc (mb, tlab_next_addr_var);
1015 mono_mb_emit_ldloc (mb, new_next_var);
1016 mono_mb_emit_byte (mb, CEE_STIND_I);
1018 /*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. */
1019 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
1020 mono_mb_emit_byte (mb, CEE_MONO_MEMORY_BARRIER);
1021 mono_mb_emit_i4 (mb, MONO_MEMORY_BARRIER_REL);
1024 mono_mb_emit_ldloc (mb, p_var);
1025 mono_mb_emit_ldarg (mb, 0);
1026 mono_mb_emit_byte (mb, CEE_STIND_I);
1028 if (atype == ATYPE_VECTOR) {
1029 /* arr->max_length = max_length; */
1030 mono_mb_emit_ldloc (mb, p_var);
1031 mono_mb_emit_ldflda (mb, MONO_STRUCT_OFFSET (MonoArray, max_length));
1032 mono_mb_emit_ldarg (mb, 1);
1033 #ifdef MONO_BIG_ARRAYS
1034 mono_mb_emit_byte (mb, CEE_STIND_I);
1036 mono_mb_emit_byte (mb, CEE_STIND_I4);
1038 } else if (atype == ATYPE_STRING) {
1039 /* need to set length and clear the last char */
1040 /* s->length = len; */
1041 mono_mb_emit_ldloc (mb, p_var);
1042 mono_mb_emit_icon (mb, MONO_STRUCT_OFFSET (MonoString, length));
1043 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1044 mono_mb_emit_ldarg (mb, 1);
1045 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
1046 /* s->chars [len] = 0; */
1047 mono_mb_emit_ldloc (mb, p_var);
1048 mono_mb_emit_ldloc (mb, size_var);
1049 mono_mb_emit_icon (mb, 2);
1050 mono_mb_emit_byte (mb, MONO_CEE_SUB);
1051 mono_mb_emit_byte (mb, MONO_CEE_ADD);
1052 mono_mb_emit_icon (mb, 0);
1053 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
1057 We must make sure both vtable and max_length are globaly visible before returning to managed land.
1059 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
1060 mono_mb_emit_byte (mb, CEE_MONO_MEMORY_BARRIER);
1061 mono_mb_emit_i4 (mb, MONO_MEMORY_BARRIER_REL);
1064 mono_mb_emit_ldloc (mb, p_var);
1065 mono_mb_emit_byte (mb, CEE_RET);
1068 res = mono_mb_create_method (mb, csig, 8);
1070 mono_method_get_header (res)->init_locals = FALSE;
1072 info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
1073 info->gc_name = "sgen";
1074 info->alloc_type = atype;
1075 mono_marshal_set_wrapper_info (res, info);
1082 mono_gc_get_aligned_size_for_allocator (int size)
1084 int aligned_size = size;
1085 aligned_size += ALLOC_ALIGN - 1;
1086 aligned_size &= ~(ALLOC_ALIGN - 1);
1087 return aligned_size;
1091 * Generate an allocator method implementing the fast path of mono_gc_alloc_obj ().
1092 * The signature of the called method is:
1093 * object allocate (MonoVTable *vtable)
1096 mono_gc_get_managed_allocator (MonoClass *klass, gboolean for_box, gboolean known_instance_size)
1098 #ifdef MANAGED_ALLOCATION
1100 #ifdef HAVE_KW_THREAD
1101 int tlab_next_offset = -1;
1102 int tlab_temp_end_offset = -1;
1103 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1104 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1106 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1109 if (collect_before_allocs)
1111 if (!mono_runtime_has_tls_get ())
1113 if (klass->instance_size > tlab_size)
1115 if (known_instance_size && ALIGN_TO (klass->instance_size, ALLOC_ALIGN) >= MAX_SMALL_OBJ_SIZE)
1118 if (klass->has_finalize || mono_class_is_marshalbyref (klass) || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
1122 if (klass->byval_arg.type == MONO_TYPE_STRING)
1123 return mono_gc_get_managed_allocator_by_type (ATYPE_STRING);
1124 /* Generic classes have dynamic field and can go above MAX_SMALL_OBJ_SIZE. */
1125 if (known_instance_size)
1126 return mono_gc_get_managed_allocator_by_type (ATYPE_SMALL);
1128 return mono_gc_get_managed_allocator_by_type (ATYPE_NORMAL);
1135 mono_gc_get_managed_array_allocator (MonoClass *klass)
1137 #ifdef MANAGED_ALLOCATION
1138 #ifdef HAVE_KW_THREAD
1139 int tlab_next_offset = -1;
1140 int tlab_temp_end_offset = -1;
1141 MONO_THREAD_VAR_OFFSET (tlab_next, tlab_next_offset);
1142 MONO_THREAD_VAR_OFFSET (tlab_temp_end, tlab_temp_end_offset);
1144 if (tlab_next_offset == -1 || tlab_temp_end_offset == -1)
1148 if (klass->rank != 1)
1150 if (!mono_runtime_has_tls_get ())
1152 if (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS)
1154 if (has_per_allocation_action)
1156 g_assert (!mono_class_has_finalizer (klass) && !mono_class_is_marshalbyref (klass));
1158 return mono_gc_get_managed_allocator_by_type (ATYPE_VECTOR);
1165 sgen_set_use_managed_allocator (gboolean flag)
1167 use_managed_allocator = flag;
1171 mono_gc_get_managed_allocator_by_type (int atype)
1173 #ifdef MANAGED_ALLOCATION
1176 if (!use_managed_allocator)
1179 if (!mono_runtime_has_tls_get ())
1182 res = alloc_method_cache [atype];
1186 res = create_allocator (atype);
1188 if (alloc_method_cache [atype]) {
1189 mono_free_method (res);
1190 res = alloc_method_cache [atype];
1192 mono_memory_barrier ();
1193 alloc_method_cache [atype] = res;
1204 mono_gc_get_managed_allocator_types (void)
1210 sgen_is_managed_allocator (MonoMethod *method)
1214 for (i = 0; i < ATYPE_NUM; ++i)
1215 if (method == alloc_method_cache [i])
1221 sgen_has_managed_allocator (void)
1225 for (i = 0; i < ATYPE_NUM; ++i)
1226 if (alloc_method_cache [i])
1231 #ifdef HEAVY_STATISTICS
1233 sgen_alloc_init_heavy_stats (void)
1235 mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced);
1236 mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced);
1237 mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_los);
1241 #endif /*HAVE_SGEN_GC*/