mono/sgen/sgen-gc.h

   1 /*
   2  * sgen-gc.c: Simple generational GC.
   3  *
   4  * Copyright 2001-2003 Ximian, Inc
   5  * Copyright 2003-2010 Novell, Inc.
   6  * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
   7  * Copyright (C) 2012 Xamarin Inc
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Library General Public
  11  * License 2.0 as published by the Free Software Foundation;
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Library General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Library General Public
  19  * License 2.0 along with this library; if not, write to the Free
  20  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22 #ifndef __MONO_SGENGC_H__
  23 #define __MONO_SGENGC_H__
  24
  25 /* pthread impl */
  26 #include "config.h"
  27
  28 #ifdef HAVE_SGEN_GC
  29
  30 typedef struct _SgenThreadInfo SgenThreadInfo;
  31 #undef THREAD_INFO_TYPE
  32 #define THREAD_INFO_TYPE SgenThreadInfo
  33
  34 #include <glib.h>
  35 #include <stdio.h>
  36 #ifdef HAVE_PTHREAD_H
  37 #include <pthread.h>
  38 #endif
  39 #include <stdint.h>
  40 #include "mono/utils/mono-compiler.h"
  41 #include "mono/utils/atomic.h"
  42 #include "mono/utils/mono-os-mutex.h"
  43 #include "mono/sgen/sgen-conf.h"
  44 #include "mono/sgen/sgen-hash-table.h"
  45 #include "mono/sgen/sgen-protocol.h"
  46 #include "mono/sgen/gc-internal-agnostic.h"
  47
  48 /* The method used to clear the nursery */
  49 /* Clearing at nursery collections is the safest, but has bad interactions with caches.
  50  * Clearing at TLAB creation is much faster, but more complex and it might expose hard
  51  * to find bugs.
  52  */
  53 typedef enum {
  54         CLEAR_AT_GC,
  55         CLEAR_AT_TLAB_CREATION,
  56         CLEAR_AT_TLAB_CREATION_DEBUG
  57 } NurseryClearPolicy;
  58
  59 NurseryClearPolicy sgen_get_nursery_clear_policy (void);
  60
  61 #if !defined(__MACH__) && !MONO_MACH_ARCH_SUPPORTED && defined(HAVE_PTHREAD_KILL)
  62 #define SGEN_POSIX_STW 1
  63 #endif
  64
  65 /*
  66  * The nursery section uses this struct.
  67  */
  68 typedef struct _GCMemSection GCMemSection;
  69 struct _GCMemSection {
  70         char *data;
  71         mword size;
  72         /* pointer where more data could be allocated if it fits */
  73         char *next_data;
  74         char *end_data;
  75         /*
  76          * scan starts is an array of pointers to objects equally spaced in the allocation area
  77          * They let use quickly find pinned objects from pinning pointers.
  78          */
  79         char **scan_starts;
  80         /* in major collections indexes in the pin_queue for objects that pin this section */
  81         size_t pin_queue_first_entry;
  82         size_t pin_queue_last_entry;
  83         size_t num_scan_start;
  84 };
  85
  86 /*
  87  * Recursion is not allowed for the thread lock.
  88  */
  89 #define LOCK_DECLARE(name) mono_mutex_t name
  90 /* if changing LOCK_INIT to something that isn't idempotent, look at
  91    its use in mono_gc_base_init in sgen-gc.c */
  92 #define LOCK_INIT(name) mono_os_mutex_init (&(name))
  93 #define LOCK_GC do { sgen_gc_lock (); } while (0)
  94 #define UNLOCK_GC do { sgen_gc_unlock (); } while (0)
  95
  96 extern LOCK_DECLARE (sgen_interruption_mutex);
  97
  98 #define LOCK_INTERRUPTION do {  \
  99         MONO_TRY_BLOCKING       \
 100         mono_os_mutex_lock (&sgen_interruption_mutex);  \
 101         MONO_FINISH_TRY_BLOCKING        \
 102 } while (0)
 103
 104 #define UNLOCK_INTERRUPTION mono_os_mutex_unlock (&sgen_interruption_mutex)
 105
 106 /* FIXME: Use InterlockedAdd & InterlockedAdd64 to reduce the CAS cost. */
 107 #define SGEN_CAS        InterlockedCompareExchange
 108 #define SGEN_CAS_PTR    InterlockedCompareExchangePointer
 109 #define SGEN_ATOMIC_ADD(x,i)    do {                                    \
 110                 int __old_x;                                            \
 111                 do {                                                    \
 112                         __old_x = (x);                                  \
 113                 } while (InterlockedCompareExchange (&(x), __old_x + (i), __old_x) != __old_x); \
 114         } while (0)
 115 #define SGEN_ATOMIC_ADD_P(x,i) do { \
 116                 size_t __old_x;                                            \
 117                 do {                                                    \
 118                         __old_x = (x);                                  \
 119                 } while (InterlockedCompareExchangePointer ((void**)&(x), (void*)(__old_x + (i)), (void*)__old_x) != (void*)__old_x); \
 120         } while (0)
 121
 122 #ifdef HEAVY_STATISTICS
 123 extern guint64 stat_objects_alloced_degraded;
 124 extern guint64 stat_bytes_alloced_degraded;
 125 extern guint64 stat_copy_object_called_major;
 126 extern guint64 stat_objects_copied_major;
 127 #endif
 128
 129 #define SGEN_ASSERT(level, a, ...) do { \
 130         if (G_UNLIKELY ((level) <= SGEN_MAX_ASSERT_LEVEL && !(a))) {    \
 131                 g_error (__VA_ARGS__);  \
 132 } } while (0)
 133
 134
 135 #define SGEN_LOG(level, format, ...) do {      \
 136         if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) {        \
 137                 mono_gc_printf (gc_debug_file, format "\n", ##__VA_ARGS__);     \
 138 } } while (0)
 139
 140 #define SGEN_COND_LOG(level, cond, format, ...) do {    \
 141         if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) {        \
 142                 if (cond)       \
 143                         mono_gc_printf (gc_debug_file, format "\n", ##__VA_ARGS__);     \
 144 } } while (0)
 145
 146 extern int gc_debug_level;
 147 extern FILE* gc_debug_file;
 148
 149 extern int current_collection_generation;
 150
 151 extern unsigned int sgen_global_stop_count;
 152
 153 #define SGEN_ALLOC_ALIGN                8
 154 #define SGEN_ALLOC_ALIGN_BITS   3
 155
 156 /* s must be non-negative */
 157 #define SGEN_CAN_ALIGN_UP(s)            ((s) <= SIZE_MAX - (SGEN_ALLOC_ALIGN - 1))
 158 #define SGEN_ALIGN_UP(s)                (((s)+(SGEN_ALLOC_ALIGN-1)) & ~(SGEN_ALLOC_ALIGN-1))
 159
 160 #if SIZEOF_VOID_P == 4
 161 #define ONE_P 1
 162 #else
 163 #define ONE_P 1ll
 164 #endif
 165
 166 static inline guint
 167 sgen_aligned_addr_hash (gconstpointer ptr)
 168 {
 169         return GPOINTER_TO_UINT (ptr) >> 3;
 170 }
 171
 172 #define SGEN_PTR_IN_NURSERY(p,bits,start,end)   (((mword)(p) & ~((1 << (bits)) - 1)) == (mword)(start))
 173
 174 #ifdef USER_CONFIG
 175
 176 /* good sizes are 512KB-1MB: larger ones increase a lot memzeroing time */
 177 #define DEFAULT_NURSERY_SIZE (sgen_nursery_size)
 178 extern size_t sgen_nursery_size;
 179 /* The number of trailing 0 bits in DEFAULT_NURSERY_SIZE */
 180 #define DEFAULT_NURSERY_BITS (sgen_nursery_bits)
 181 extern int sgen_nursery_bits;
 182
 183 #else
 184
 185 #define DEFAULT_NURSERY_SIZE (4*1024*1024)
 186 #define DEFAULT_NURSERY_BITS 22
 187
 188 #endif
 189
 190 extern char *sgen_nursery_start;
 191 extern char *sgen_nursery_end;
 192
 193 static inline MONO_ALWAYS_INLINE gboolean
 194 sgen_ptr_in_nursery (void *p)
 195 {
 196         return SGEN_PTR_IN_NURSERY ((p), DEFAULT_NURSERY_BITS, sgen_nursery_start, sgen_nursery_end);
 197 }
 198
 199 static inline MONO_ALWAYS_INLINE char*
 200 sgen_get_nursery_start (void)
 201 {
 202         return sgen_nursery_start;
 203 }
 204
 205 static inline MONO_ALWAYS_INLINE char*
 206 sgen_get_nursery_end (void)
 207 {
 208         return sgen_nursery_end;
 209 }
 210
 211 /*
 212  * We use the lowest three bits in the vtable pointer of objects to tag whether they're
 213  * forwarded, pinned, and/or cemented.  These are the valid states:
 214  *
 215  * | State            | bits |
 216  * |------------------+------+
 217  * | default          |  000 |
 218  * | forwarded        |  001 |
 219  * | pinned           |  010 |
 220  * | pinned, cemented |  110 |
 221  *
 222  * We store them in the vtable slot because the bits are used in the sync block for other
 223  * purposes: if we merge them and alloc the sync blocks aligned to 8 bytes, we can change
 224  * this and use bit 3 in the syncblock (with the lower two bits both set for forwarded, that
 225  * would be an invalid combination for the monitor and hash code).
 226  */
 227
 228 #include "sgen-tagged-pointer.h"
 229
 230 #define SGEN_VTABLE_BITS_MASK   SGEN_TAGGED_POINTER_MASK
 231
 232 #define SGEN_POINTER_IS_TAGGED_FORWARDED(p)     SGEN_POINTER_IS_TAGGED_1((p))
 233 #define SGEN_POINTER_TAG_FORWARDED(p)           SGEN_POINTER_TAG_1((p))
 234
 235 #define SGEN_POINTER_IS_TAGGED_PINNED(p)        SGEN_POINTER_IS_TAGGED_2((p))
 236 #define SGEN_POINTER_TAG_PINNED(p)              SGEN_POINTER_TAG_2((p))
 237
 238 #define SGEN_POINTER_IS_TAGGED_CEMENTED(p)      SGEN_POINTER_IS_TAGGED_4((p))
 239 #define SGEN_POINTER_TAG_CEMENTED(p)            SGEN_POINTER_TAG_4((p))
 240
 241 #define SGEN_POINTER_UNTAG_VTABLE(p)            SGEN_POINTER_UNTAG_ALL((p))
 242
 243 /* returns NULL if not forwarded, or the forwarded address */
 244 #define SGEN_VTABLE_IS_FORWARDED(vtable) (SGEN_POINTER_IS_TAGGED_FORWARDED ((vtable)) ? SGEN_POINTER_UNTAG_VTABLE ((vtable)) : NULL)
 245 #define SGEN_OBJECT_IS_FORWARDED(obj) (SGEN_VTABLE_IS_FORWARDED (((mword*)(obj))[0]))
 246
 247 #define SGEN_VTABLE_IS_PINNED(vtable) SGEN_POINTER_IS_TAGGED_PINNED ((vtable))
 248 #define SGEN_OBJECT_IS_PINNED(obj) (SGEN_VTABLE_IS_PINNED (((mword*)(obj))[0]))
 249
 250 #define SGEN_OBJECT_IS_CEMENTED(obj) (SGEN_POINTER_IS_TAGGED_CEMENTED (((mword*)(obj))[0]))
 251
 252 /* set the forwarded address fw_addr for object obj */
 253 #define SGEN_FORWARD_OBJECT(obj,fw_addr) do {                           \
 254                 *(void**)(obj) = SGEN_POINTER_TAG_FORWARDED ((fw_addr));        \
 255         } while (0)
 256 #define SGEN_PIN_OBJECT(obj) do {       \
 257                 *(void**)(obj) = SGEN_POINTER_TAG_PINNED (*(void**)(obj)); \
 258         } while (0)
 259 #define SGEN_CEMENT_OBJECT(obj) do {    \
 260                 *(void**)(obj) = SGEN_POINTER_TAG_CEMENTED (*(void**)(obj)); \
 261         } while (0)
 262 /* Unpins and uncements */
 263 #define SGEN_UNPIN_OBJECT(obj) do {     \
 264                 *(void**)(obj) = SGEN_POINTER_UNTAG_VTABLE (*(void**)(obj)); \
 265         } while (0)
 266
 267 /*
 268  * Since we set bits in the vtable, use the macro to load it from the pointer to
 269  * an object that is potentially pinned.
 270  */
 271 #define SGEN_LOAD_VTABLE(obj)           ((GCVTable)(SGEN_POINTER_UNTAG_ALL (SGEN_LOAD_VTABLE_UNCHECKED ((obj)))))
 272
 273 /*
 274 List of what each bit on of the vtable gc bits means.
 275 */
 276 enum {
 277         SGEN_GC_BIT_BRIDGE_OBJECT = 1,
 278         SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT = 2,
 279         SGEN_GC_BIT_FINALIZER_AWARE = 4,
 280 };
 281
 282 void sgen_gc_init (void);
 283
 284 void sgen_os_init (void);
 285
 286 void sgen_update_heap_boundaries (mword low, mword high);
 287
 288 void sgen_check_section_scan_starts (GCMemSection *section);
 289
 290 void sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type);
 291
 292 /* Keep in sync with description_for_type() in sgen-internal.c! */
 293 enum {
 294         INTERNAL_MEM_PIN_QUEUE,
 295         INTERNAL_MEM_FRAGMENT,
 296         INTERNAL_MEM_SECTION,
 297         INTERNAL_MEM_SCAN_STARTS,
 298         INTERNAL_MEM_FIN_TABLE,
 299         INTERNAL_MEM_FINALIZE_ENTRY,
 300         INTERNAL_MEM_FINALIZE_READY,
 301         INTERNAL_MEM_DISLINK_TABLE,
 302         INTERNAL_MEM_DISLINK,
 303         INTERNAL_MEM_ROOTS_TABLE,
 304         INTERNAL_MEM_ROOT_RECORD,
 305         INTERNAL_MEM_STATISTICS,
 306         INTERNAL_MEM_STAT_PINNED_CLASS,
 307         INTERNAL_MEM_STAT_REMSET_CLASS,
 308         INTERNAL_MEM_GRAY_QUEUE,
 309         INTERNAL_MEM_MS_TABLES,
 310         INTERNAL_MEM_MS_BLOCK_INFO,
 311         INTERNAL_MEM_MS_BLOCK_INFO_SORT,
 312         INTERNAL_MEM_WORKER_DATA,
 313         INTERNAL_MEM_THREAD_POOL_JOB,
 314         INTERNAL_MEM_BRIDGE_DATA,
 315         INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE,
 316         INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE_ENTRY,
 317         INTERNAL_MEM_BRIDGE_HASH_TABLE,
 318         INTERNAL_MEM_BRIDGE_HASH_TABLE_ENTRY,
 319         INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE,
 320         INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE_ENTRY,
 321         INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE,
 322         INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE_ENTRY,
 323         INTERNAL_MEM_TARJAN_OBJ_BUCKET,
 324         INTERNAL_MEM_BRIDGE_DEBUG,
 325         INTERNAL_MEM_TOGGLEREF_DATA,
 326         INTERNAL_MEM_CARDTABLE_MOD_UNION,
 327         INTERNAL_MEM_BINARY_PROTOCOL,
 328         INTERNAL_MEM_TEMPORARY,
 329         INTERNAL_MEM_FIRST_CLIENT
 330 };
 331
 332 enum {
 333         GENERATION_NURSERY,
 334         GENERATION_OLD,
 335         GENERATION_MAX
 336 };
 337
 338 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
 339 #define BINARY_PROTOCOL_ARG(x)  ,x
 340 #else
 341 #define BINARY_PROTOCOL_ARG(x)
 342 #endif
 343
 344 void sgen_init_internal_allocator (void);
 345
 346 #define SGEN_DEFINE_OBJECT_VTABLE
 347 #ifdef SGEN_CLIENT_HEADER
 348 #include SGEN_CLIENT_HEADER
 349 #else
 350 #include "metadata/sgen-client-mono.h"
 351 #endif
 352 #undef SGEN_DEFINE_OBJECT_VTABLE
 353
 354 #include "mono/sgen/sgen-descriptor.h"
 355 #include "mono/sgen/sgen-gray.h"
 356
 357 /* the runtime can register areas of memory as roots: we keep two lists of roots,
 358  * a pinned root set for conservatively scanned roots and a normal one for
 359  * precisely scanned roots (currently implemented as a single list).
 360  */
 361 typedef struct _RootRecord RootRecord;
 362 struct _RootRecord {
 363         char *end_root;
 364         SgenDescriptor root_desc;
 365         int source;
 366         const char *msg;
 367 };
 368
 369 enum {
 370         ROOT_TYPE_NORMAL = 0, /* "normal" roots */
 371         ROOT_TYPE_PINNED = 1, /* roots without a GC descriptor */
 372         ROOT_TYPE_WBARRIER = 2, /* roots with a write barrier */
 373         ROOT_TYPE_NUM
 374 };
 375
 376 extern SgenHashTable roots_hash [ROOT_TYPE_NUM];
 377
 378 int sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg);
 379 void sgen_deregister_root (char* addr);
 380
 381 typedef void (*IterateObjectCallbackFunc) (GCObject*, size_t, void*);
 382
 383 void sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries);
 384
 385 /* eventually share with MonoThread? */
 386 /*
 387  * This structure extends the MonoThreadInfo structure.
 388  */
 389 struct _SgenThreadInfo {
 390         SgenClientThreadInfo client_info;
 391
 392         char **tlab_next_addr;
 393         char **tlab_start_addr;
 394         char **tlab_temp_end_addr;
 395         char **tlab_real_end_addr;
 396
 397 #ifndef HAVE_KW_THREAD
 398         char *tlab_start;
 399         char *tlab_next;
 400         char *tlab_temp_end;
 401         char *tlab_real_end;
 402 #endif
 403 };
 404
 405 gboolean sgen_is_worker_thread (MonoNativeThreadId thread);
 406
 407 typedef void (*CopyOrMarkObjectFunc) (GCObject**, SgenGrayQueue*);
 408 typedef void (*ScanObjectFunc) (GCObject *obj, SgenDescriptor desc, SgenGrayQueue*);
 409 typedef void (*ScanVTypeFunc) (GCObject *full_object, char *start, SgenDescriptor desc, SgenGrayQueue* BINARY_PROTOCOL_ARG (size_t size));
 410 typedef gboolean (*DrainGrayStackFunc) (SgenGrayQueue *queue);
 411
 412 typedef struct {
 413         CopyOrMarkObjectFunc copy_or_mark_object;
 414         ScanObjectFunc scan_object;
 415         ScanVTypeFunc scan_vtype;
 416         /* Drain stack optimized for the above functions */
 417         DrainGrayStackFunc drain_gray_stack;
 418         /*FIXME add allocation function? */
 419 } SgenObjectOperations;
 420
 421 typedef struct
 422 {
 423         SgenObjectOperations *ops;
 424         SgenGrayQueue *queue;
 425 } ScanCopyContext;
 426
 427 #define CONTEXT_FROM_OBJECT_OPERATIONS(ops, queue) ((ScanCopyContext) { (ops), (queue) })
 428
 429 void sgen_report_internal_mem_usage (void);
 430 void sgen_dump_internal_mem_usage (FILE *heap_dump_file);
 431 void sgen_dump_section (GCMemSection *section, const char *type);
 432 void sgen_dump_occupied (char *start, char *end, char *section_start);
 433
 434 void sgen_register_fixed_internal_mem_type (int type, size_t size);
 435
 436 void* sgen_alloc_internal (int type);
 437 void sgen_free_internal (void *addr, int type);
 438
 439 void* sgen_alloc_internal_dynamic (size_t size, int type, gboolean assert_on_failure);
 440 void sgen_free_internal_dynamic (void *addr, size_t size, int type);
 441
 442 void sgen_pin_stats_enable (void);
 443 void sgen_pin_stats_register_object (GCObject *obj, size_t size);
 444 void sgen_pin_stats_register_global_remset (GCObject *obj);
 445 void sgen_pin_stats_print_class_stats (void);
 446
 447 void sgen_sort_addresses (void **array, size_t size);
 448 void sgen_add_to_global_remset (gpointer ptr, gpointer obj);
 449
 450 int sgen_get_current_collection_generation (void);
 451 gboolean sgen_collection_is_concurrent (void);
 452 gboolean sgen_concurrent_collection_in_progress (void);
 453
 454 typedef struct _SgenFragment SgenFragment;
 455
 456 struct _SgenFragment {
 457         SgenFragment *next;
 458         char *fragment_start;
 459         char *fragment_next; /* the current soft limit for allocation */
 460         char *fragment_end;
 461         SgenFragment *next_in_order; /* We use a different entry for all active fragments so we can avoid SMR. */
 462 };
 463
 464 typedef struct {
 465         SgenFragment *alloc_head; /* List head to be used when allocating memory. Walk with fragment_next. */
 466         SgenFragment *region_head; /* List head of the region used by this allocator. Walk with next_in_order. */
 467 } SgenFragmentAllocator;
 468
 469 void sgen_fragment_allocator_add (SgenFragmentAllocator *allocator, char *start, char *end);
 470 void sgen_fragment_allocator_release (SgenFragmentAllocator *allocator);
 471 void* sgen_fragment_allocator_serial_alloc (SgenFragmentAllocator *allocator, size_t size);
 472 void* sgen_fragment_allocator_par_alloc (SgenFragmentAllocator *allocator, size_t size);
 473 void* sgen_fragment_allocator_serial_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
 474 void* sgen_fragment_allocator_par_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
 475 SgenFragment* sgen_fragment_allocator_alloc (void);
 476 void sgen_clear_allocator_fragments (SgenFragmentAllocator *allocator);
 477 void sgen_clear_range (char *start, char *end);
 478
 479
 480 /*
 481 This is a space/speed compromise as we need to make sure the from/to space check is both O(1)
 482 and only hit cache hot memory. On a 4Mb nursery it requires 1024 bytes, or 3% of your average
 483 L1 cache. On small configs with a 512kb nursery, this goes to 0.4%.
 484
 485 Experimental results on how much space we waste with a 4Mb nursery:
 486
 487 Note that the wastage applies to the half nursery, or 2Mb:
 488
 489 Test 1 (compiling corlib):
 490 9: avg: 3.1k
 491 8: avg: 1.6k
 492
 493 */
 494 #define SGEN_TO_SPACE_GRANULE_BITS 9
 495 #define SGEN_TO_SPACE_GRANULE_IN_BYTES (1 << SGEN_TO_SPACE_GRANULE_BITS)
 496
 497 extern char *sgen_space_bitmap;
 498 extern size_t sgen_space_bitmap_size;
 499
 500 static inline gboolean
 501 sgen_nursery_is_to_space (void *object)
 502 {
 503         size_t idx = ((char*)object - sgen_nursery_start) >> SGEN_TO_SPACE_GRANULE_BITS;
 504         size_t byte = idx >> 3;
 505         size_t bit = idx & 0x7;
 506
 507         SGEN_ASSERT (4, sgen_ptr_in_nursery (object), "object %p is not in nursery [%p - %p]", object, sgen_get_nursery_start (), sgen_get_nursery_end ());
 508         SGEN_ASSERT (4, byte < sgen_space_bitmap_size, "byte index %zd out of range (%zd)", byte, sgen_space_bitmap_size);
 509
 510         return (sgen_space_bitmap [byte] & (1 << bit)) != 0;
 511 }
 512
 513 static inline gboolean
 514 sgen_nursery_is_from_space (void *object)
 515 {
 516         return !sgen_nursery_is_to_space (object);
 517 }
 518
 519 static inline gboolean
 520 sgen_nursery_is_object_alive (GCObject *obj)
 521 {
 522         /* FIXME put this asserts under a non default level */
 523         g_assert (sgen_ptr_in_nursery (obj));
 524
 525         if (sgen_nursery_is_to_space (obj))
 526                 return TRUE;
 527
 528         if (SGEN_OBJECT_IS_PINNED (obj) || SGEN_OBJECT_IS_FORWARDED (obj))
 529                 return TRUE;
 530
 531         return FALSE;
 532 }
 533
 534 typedef struct {
 535         gboolean is_split;
 536
 537         GCObject* (*alloc_for_promotion) (GCVTable vtable, GCObject *obj, size_t objsize, gboolean has_references);
 538
 539         SgenObjectOperations serial_ops;
 540
 541         void (*prepare_to_space) (char *to_space_bitmap, size_t space_bitmap_size);
 542         void (*clear_fragments) (void);
 543         SgenFragment* (*build_fragments_get_exclude_head) (void);
 544         void (*build_fragments_release_exclude_head) (void);
 545         void (*build_fragments_finish) (SgenFragmentAllocator *allocator);
 546         void (*init_nursery) (SgenFragmentAllocator *allocator, char *start, char *end);
 547
 548         gboolean (*handle_gc_param) (const char *opt); /* Optional */
 549         void (*print_gc_param_usage) (void); /* Optional */
 550 } SgenMinorCollector;
 551
 552 extern SgenMinorCollector sgen_minor_collector;
 553
 554 void sgen_simple_nursery_init (SgenMinorCollector *collector);
 555 void sgen_split_nursery_init (SgenMinorCollector *collector);
 556
 557 /* Updating references */
 558
 559 #ifdef SGEN_CHECK_UPDATE_REFERENCE
 560 gboolean sgen_thread_pool_is_thread_pool_thread (MonoNativeThreadId some_thread) MONO_INTERNAL;
 561 static inline void
 562 sgen_update_reference (GCObject **p, GCObject *o, gboolean allow_null)
 563 {
 564         if (!allow_null)
 565                 SGEN_ASSERT (0, o, "Cannot update a reference with a NULL pointer");
 566         SGEN_ASSERT (0, !sgen_thread_pool_is_thread_pool_thread (mono_native_thread_id_get ()), "Can't update a reference in the worker thread");
 567         *p = o;
 568 }
 569
 570 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o)   sgen_update_reference ((GCObject**)(p), (GCObject*)(o), TRUE)
 571 #define SGEN_UPDATE_REFERENCE(p,o)              sgen_update_reference ((GCObject**)(p), (GCObject*)(o), FALSE)
 572 #else
 573 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o)   (*(GCObject**)(p) = (GCObject*)(o))
 574 #define SGEN_UPDATE_REFERENCE(p,o)              SGEN_UPDATE_REFERENCE_ALLOW_NULL ((p), (o))
 575 #endif
 576
 577 /* Major collector */
 578
 579 typedef void (*sgen_cardtable_block_callback) (mword start, mword size);
 580 void sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
 581
 582 typedef enum {
 583         ITERATE_OBJECTS_SWEEP = 1,
 584         ITERATE_OBJECTS_NON_PINNED = 2,
 585         ITERATE_OBJECTS_PINNED = 4,
 586         ITERATE_OBJECTS_ALL = ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED,
 587         ITERATE_OBJECTS_SWEEP_NON_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED,
 588         ITERATE_OBJECTS_SWEEP_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_PINNED,
 589         ITERATE_OBJECTS_SWEEP_ALL = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED
 590 } IterateObjectsFlags;
 591
 592 typedef struct
 593 {
 594         size_t num_scanned_objects;
 595         size_t num_unique_scanned_objects;
 596 } ScannedObjectCounts;
 597
 598 typedef struct _SgenMajorCollector SgenMajorCollector;
 599 struct _SgenMajorCollector {
 600         size_t section_size;
 601         gboolean is_concurrent;
 602         gboolean needs_thread_pool;
 603         gboolean supports_cardtable;
 604         gboolean sweeps_lazily;
 605
 606         /*
 607          * This is set to TRUE by the sweep if the next major
 608          * collection should be synchronous (for evacuation).  For
 609          * non-concurrent collectors, this should be NULL.
 610          */
 611         gboolean *want_synchronous_collection;
 612
 613         void* (*alloc_heap) (mword nursery_size, mword nursery_align, int nursery_bits);
 614         gboolean (*is_object_live) (GCObject *obj);
 615         GCObject* (*alloc_small_pinned_obj) (GCVTable vtable, size_t size, gboolean has_references);
 616         GCObject* (*alloc_degraded) (GCVTable vtable, size_t size);
 617
 618         SgenObjectOperations major_ops_serial;
 619         SgenObjectOperations major_ops_concurrent_start;
 620         SgenObjectOperations major_ops_concurrent_finish;
 621
 622         GCObject* (*alloc_object) (GCVTable vtable, size_t size, gboolean has_references);
 623         void (*free_pinned_object) (GCObject *obj, size_t size);
 624
 625         /*
 626          * This is used for domain unloading, heap walking from the logging profiler, and
 627          * debugging.  Can assume the world is stopped.
 628          */
 629         void (*iterate_objects) (IterateObjectsFlags flags, IterateObjectCallbackFunc callback, void *data);
 630
 631         void (*free_non_pinned_object) (GCObject *obj, size_t size);
 632         void (*pin_objects) (SgenGrayQueue *queue);
 633         void (*pin_major_object) (GCObject *obj, SgenGrayQueue *queue);
 634         void (*scan_card_table) (gboolean mod_union, ScanCopyContext ctx);
 635         void (*iterate_live_block_ranges) (sgen_cardtable_block_callback callback);
 636         void (*update_cardtable_mod_union) (void);
 637         void (*init_to_space) (void);
 638         void (*sweep) (void);
 639         gboolean (*have_swept) (void);
 640         void (*finish_sweeping) (void);
 641         void (*free_swept_blocks) (size_t allowance);
 642         void (*check_scan_starts) (void);
 643         void (*dump_heap) (FILE *heap_dump_file);
 644         gint64 (*get_used_size) (void);
 645         void (*start_nursery_collection) (void);
 646         void (*finish_nursery_collection) (void);
 647         void (*start_major_collection) (void);
 648         void (*finish_major_collection) (ScannedObjectCounts *counts);
 649         gboolean (*ptr_is_in_non_pinned_space) (char *ptr, char **start);
 650         gboolean (*ptr_is_from_pinned_alloc) (char *ptr);
 651         void (*report_pinned_memory_usage) (void);
 652         size_t (*get_num_major_sections) (void);
 653         size_t (*get_bytes_survived_last_sweep) (void);
 654         gboolean (*handle_gc_param) (const char *opt);
 655         void (*print_gc_param_usage) (void);
 656         void (*post_param_init) (SgenMajorCollector *collector);
 657         gboolean (*is_valid_object) (char *ptr);
 658         GCVTable (*describe_pointer) (char *pointer);
 659         guint8* (*get_cardtable_mod_union_for_reference) (char *object);
 660         long long (*get_and_reset_num_major_objects_marked) (void);
 661         void (*count_cards) (long long *num_total_cards, long long *num_marked_cards);
 662 };
 663
 664 extern SgenMajorCollector major_collector;
 665
 666 void sgen_marksweep_init (SgenMajorCollector *collector);
 667 void sgen_marksweep_fixed_init (SgenMajorCollector *collector);
 668 void sgen_marksweep_par_init (SgenMajorCollector *collector);
 669 void sgen_marksweep_fixed_par_init (SgenMajorCollector *collector);
 670 void sgen_marksweep_conc_init (SgenMajorCollector *collector);
 671 SgenMajorCollector* sgen_get_major_collector (void);
 672
 673
 674 typedef struct _SgenRememberedSet {
 675         void (*wbarrier_set_field) (GCObject *obj, gpointer field_ptr, GCObject* value);
 676         void (*wbarrier_arrayref_copy) (gpointer dest_ptr, gpointer src_ptr, int count);
 677         void (*wbarrier_value_copy) (gpointer dest, gpointer src, int count, size_t element_size);
 678         void (*wbarrier_object_copy) (GCObject* obj, GCObject *src);
 679         void (*wbarrier_generic_nostore) (gpointer ptr);
 680         void (*record_pointer) (gpointer ptr);
 681
 682         void (*scan_remsets) (ScanCopyContext ctx);
 683
 684         void (*clear_cards) (void);
 685
 686         void (*finish_minor_collection) (void);
 687         gboolean (*find_address) (char *addr);
 688         gboolean (*find_address_with_cards) (char *cards_start, guint8 *cards, char *addr);
 689 } SgenRememberedSet;
 690
 691 SgenRememberedSet *sgen_get_remset (void);
 692
 693 /*
 694  * These must be kept in sync with object.h.  They're here for using SGen independently of
 695  * Mono.
 696  */
 697 void mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count);
 698 void mono_gc_wbarrier_generic_nostore (gpointer ptr);
 699 void mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value);
 700 void mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value);
 701
 702 void sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap);
 703
 704 static inline SgenDescriptor
 705 sgen_obj_get_descriptor (GCObject *obj)
 706 {
 707         GCVTable vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
 708         SGEN_ASSERT (9, !SGEN_POINTER_IS_TAGGED_ANY (vtable), "Object can't be tagged");
 709         return sgen_vtable_get_descriptor (vtable);
 710 }
 711
 712 static inline SgenDescriptor
 713 sgen_obj_get_descriptor_safe (GCObject *obj)
 714 {
 715         GCVTable vtable = SGEN_LOAD_VTABLE (obj);
 716         return sgen_vtable_get_descriptor (vtable);
 717 }
 718
 719 static mword sgen_client_par_object_get_size (GCVTable vtable, GCObject* o);
 720 static mword sgen_client_slow_object_get_size (GCVTable vtable, GCObject* o);
 721
 722 static inline mword
 723 sgen_safe_object_get_size (GCObject *obj)
 724 {
 725        GCObject *forwarded;
 726
 727        if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj)))
 728                obj = forwarded;
 729
 730        return sgen_client_par_object_get_size (SGEN_LOAD_VTABLE (obj), obj);
 731 }
 732
 733 static inline gboolean
 734 sgen_safe_object_is_small (GCObject *obj, int type)
 735 {
 736         if (type <= DESC_TYPE_MAX_SMALL_OBJ)
 737                 return TRUE;
 738         return SGEN_ALIGN_UP (sgen_safe_object_get_size ((GCObject*)obj)) <= SGEN_MAX_SMALL_OBJ_SIZE;
 739 }
 740
 741 /*
 742  * This variant guarantees to return the exact size of the object
 743  * before alignment. Needed for canary support.
 744  */
 745 static inline guint
 746 sgen_safe_object_get_size_unaligned (GCObject *obj)
 747 {
 748         GCObject *forwarded;
 749
 750         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
 751                 obj = (GCObject*)forwarded;
 752         }
 753
 754         return sgen_client_slow_object_get_size (SGEN_LOAD_VTABLE (obj), obj);
 755 }
 756
 757 #ifdef SGEN_CLIENT_HEADER
 758 #include SGEN_CLIENT_HEADER
 759 #else
 760 #include "metadata/sgen-client-mono.h"
 761 #endif
 762
 763 gboolean sgen_object_is_live (GCObject *obj);
 764
 765 void  sgen_init_fin_weak_hash (void);
 766
 767 /* FIXME: move the toggleref stuff out of here */
 768 void sgen_mark_togglerefs (char *start, char *end, ScanCopyContext ctx);
 769 void sgen_clear_togglerefs (char *start, char *end, ScanCopyContext ctx);
 770
 771 void sgen_process_togglerefs (void);
 772 void sgen_register_test_toggleref_callback (void);
 773
 774 void sgen_mark_bridge_object (GCObject *obj);
 775 void sgen_collect_bridge_objects (int generation, ScanCopyContext ctx);
 776
 777 typedef gboolean (*SgenObjectPredicateFunc) (GCObject *obj, void *user_data);
 778
 779 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
 780
 781 gboolean sgen_gc_is_object_ready_for_finalization (GCObject *object);
 782 void sgen_gc_lock (void);
 783 void sgen_gc_unlock (void);
 784
 785 void sgen_queue_finalization_entry (GCObject *obj);
 786 const char* sgen_generation_name (int generation);
 787
 788 void sgen_finalize_in_range (int generation, ScanCopyContext ctx);
 789 void sgen_null_link_in_range (int generation, ScanCopyContext ctx, gboolean track);
 790 void sgen_process_fin_stage_entries (void);
 791 gboolean sgen_have_pending_finalizers (void);
 792 void sgen_object_register_for_finalization (GCObject *obj, void *user_data);
 793
 794 int sgen_gather_finalizers_if (SgenObjectPredicateFunc predicate, void *user_data, GCObject **out_array, int out_size);
 795 void sgen_remove_finalizers_if (SgenObjectPredicateFunc predicate, void *user_data, int generation);
 796
 797 void sgen_register_disappearing_link (GCObject *obj, void **link, gboolean track, gboolean in_gc);
 798
 799 GCObject* sgen_weak_link_get (void **link_addr);
 800
 801 gboolean sgen_drain_gray_stack (ScanCopyContext ctx);
 802
 803 enum {
 804         SPACE_NURSERY,
 805         SPACE_MAJOR,
 806         SPACE_LOS
 807 };
 808
 809 void sgen_pin_object (GCObject *object, SgenGrayQueue *queue);
 810 void sgen_set_pinned_from_failed_allocation (mword objsize);
 811
 812 void sgen_ensure_free_space (size_t size);
 813 void sgen_gc_collect (int generation);
 814 void sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish);
 815
 816 int sgen_gc_collection_count (int generation);
 817 /* FIXME: what exactly does this return? */
 818 size_t sgen_gc_get_used_size (void);
 819 size_t sgen_gc_get_total_heap_allocation (void);
 820
 821 /* STW */
 822
 823 typedef struct {
 824         int generation;
 825         const char *reason;
 826         gboolean is_overflow;
 827         gint64 total_time;
 828         gint64 stw_time;
 829         gint64 bridge_time;
 830 } GGTimingInfo;
 831
 832 void sgen_stop_world (int generation);
 833 void sgen_restart_world (int generation, GGTimingInfo *timing);
 834 gboolean sgen_is_world_stopped (void);
 835
 836 gboolean sgen_set_allow_synchronous_major (gboolean flag);
 837
 838 /* LOS */
 839
 840 typedef struct _LOSObject LOSObject;
 841 struct _LOSObject {
 842         LOSObject *next;
 843         mword size; /* this is the object size, lowest bit used for pin/mark */
 844         guint8 * volatile cardtable_mod_union; /* only used by the concurrent collector */
 845 #if SIZEOF_VOID_P < 8
 846         mword dummy;            /* to align object to sizeof (double) */
 847 #endif
 848         GCObject data [MONO_ZERO_LEN_ARRAY];
 849 };
 850
 851 extern LOSObject *los_object_list;
 852 extern mword los_memory_usage;
 853
 854 void sgen_los_free_object (LOSObject *obj);
 855 void* sgen_los_alloc_large_inner (GCVTable vtable, size_t size);
 856 void sgen_los_sweep (void);
 857 gboolean sgen_ptr_is_in_los (char *ptr, char **start);
 858 void sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data);
 859 void sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
 860 void sgen_los_scan_card_table (gboolean mod_union, ScanCopyContext ctx);
 861 void sgen_los_update_cardtable_mod_union (void);
 862 void sgen_los_count_cards (long long *num_total_cards, long long *num_marked_cards);
 863 gboolean sgen_los_is_valid_object (char *object);
 864 gboolean mono_sgen_los_describe_pointer (char *ptr);
 865 LOSObject* sgen_los_header_for_object (GCObject *data);
 866 mword sgen_los_object_size (LOSObject *obj);
 867 void sgen_los_pin_object (GCObject *obj);
 868 gboolean sgen_los_object_is_pinned (GCObject *obj);
 869 void sgen_los_mark_mod_union_card (GCObject *mono_obj, void **ptr);
 870
 871
 872 /* nursery allocator */
 873
 874 void sgen_clear_nursery_fragments (void);
 875 void sgen_nursery_allocator_prepare_for_pinning (void);
 876 void sgen_nursery_allocator_set_nursery_bounds (char *nursery_start, char *nursery_end);
 877 mword sgen_build_nursery_fragments (GCMemSection *nursery_section, SgenGrayQueue *unpin_queue);
 878 void sgen_init_nursery_allocator (void);
 879 void sgen_nursery_allocator_init_heavy_stats (void);
 880 void sgen_init_allocator (void);
 881 char* sgen_nursery_alloc_get_upper_alloc_bound (void);
 882 void* sgen_nursery_alloc (size_t size);
 883 void* sgen_nursery_alloc_range (size_t size, size_t min_size, size_t *out_alloc_size);
 884 gboolean sgen_can_alloc_size (size_t size);
 885 void sgen_nursery_retire_region (void *address, ptrdiff_t size);
 886
 887 void sgen_nursery_alloc_prepare_for_minor (void);
 888 void sgen_nursery_alloc_prepare_for_major (void);
 889
 890 GCObject* sgen_alloc_for_promotion (GCObject *obj, size_t objsize, gboolean has_references);
 891
 892 GCObject* sgen_alloc_obj_nolock (GCVTable vtable, size_t size);
 893 GCObject* sgen_try_alloc_obj_nolock (GCVTable vtable, size_t size);
 894
 895 /* Threads */
 896
 897 void* sgen_thread_register (SgenThreadInfo* info, void *addr);
 898 void sgen_thread_unregister (SgenThreadInfo *p);
 899
 900 /* Finalization/ephemeron support */
 901
 902 static inline gboolean
 903 sgen_major_is_object_alive (GCObject *object)
 904 {
 905         mword objsize;
 906
 907         /* Oldgen objects can be pinned and forwarded too */
 908         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
 909                 return TRUE;
 910
 911         /*
 912          * FIXME: major_collector.is_object_live() also calculates the
 913          * size.  Avoid the double calculation.
 914          */
 915         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size (object));
 916         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
 917                 return sgen_los_object_is_pinned (object);
 918
 919         return major_collector.is_object_live (object);
 920 }
 921
 922 /*
 923  * This function returns true if @object is either alive or it belongs to the old gen
 924  * and we're currently doing a minor collection.
 925  */
 926 static inline int
 927 sgen_is_object_alive_for_current_gen (GCObject *object)
 928 {
 929         if (sgen_ptr_in_nursery (object))
 930                 return sgen_nursery_is_object_alive (object);
 931
 932         if (current_collection_generation == GENERATION_NURSERY)
 933                 return TRUE;
 934
 935         return sgen_major_is_object_alive (object);
 936 }
 937
 938 int sgen_gc_invoke_finalizers (void);
 939
 940 /* GC handles */
 941
 942 void sgen_init_gchandles (void);
 943
 944 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
 945
 946 typedef gpointer (*SgenGCHandleIterateCallback) (gpointer hidden, GCHandleType handle_type, int max_generation, gpointer user);
 947
 948 void sgen_gchandle_iterate (GCHandleType handle_type, int max_generation, SgenGCHandleIterateCallback callback, gpointer user);
 949 void sgen_gchandle_set_target (guint32 gchandle, GCObject *obj);
 950 void sgen_mark_normal_gc_handles (void *addr, SgenUserMarkFunc mark_func, void *gc_data);
 951 gpointer sgen_gchandle_get_metadata (guint32 gchandle);
 952
 953 /* Other globals */
 954
 955 extern GCMemSection *nursery_section;
 956 extern guint32 collect_before_allocs;
 957 extern guint32 verify_before_allocs;
 958 extern gboolean has_per_allocation_action;
 959 extern size_t degraded_mode;
 960 extern int default_nursery_size;
 961 extern guint32 tlab_size;
 962 extern NurseryClearPolicy nursery_clear_policy;
 963 extern gboolean sgen_try_free_some_memory;
 964
 965 extern MonoCoopMutex gc_mutex;
 966
 967 /* Nursery helpers. */
 968
 969 static inline void
 970 sgen_set_nursery_scan_start (char *p)
 971 {
 972         size_t idx = (p - (char*)nursery_section->data) / SGEN_SCAN_START_SIZE;
 973         char *old = nursery_section->scan_starts [idx];
 974         if (!old || old > p)
 975                 nursery_section->scan_starts [idx] = p;
 976 }
 977
 978
 979 /* Object Allocation */
 980
 981 typedef enum {
 982         ATYPE_NORMAL,
 983         ATYPE_VECTOR,
 984         ATYPE_SMALL,
 985         ATYPE_STRING,
 986         ATYPE_NUM
 987 } SgenAllocatorType;
 988
 989 void sgen_init_tlab_info (SgenThreadInfo* info);
 990 void sgen_clear_tlabs (void);
 991
 992 GCObject* sgen_alloc_obj (GCVTable vtable, size_t size);
 993 GCObject* sgen_alloc_obj_pinned (GCVTable vtable, size_t size);
 994 GCObject* sgen_alloc_obj_mature (GCVTable vtable, size_t size);
 995
 996 /* Debug support */
 997
 998 void sgen_check_consistency (void);
 999 void sgen_check_mod_union_consistency (void);
1000 void sgen_check_major_refs (void);
1001 void sgen_check_whole_heap (gboolean allow_missing_pinning);
1002 void sgen_check_whole_heap_stw (void);
1003 void sgen_check_objref (char *obj);
1004 void sgen_check_heap_marked (gboolean nursery_must_be_pinned);
1005 void sgen_check_nursery_objects_pinned (gboolean pinned);
1006 void sgen_check_for_xdomain_refs (void);
1007 GCObject* sgen_find_object_for_ptr (char *ptr);
1008
1009 void mono_gc_scan_for_specific_ref (GCObject *key, gboolean precise);
1010
1011 void sgen_debug_enable_heap_dump (const char *filename);
1012 void sgen_debug_dump_heap (const char *type, int num, const char *reason);
1013
1014 void sgen_debug_verify_nursery (gboolean do_dump_nursery_content);
1015 void sgen_debug_check_nursery_is_clean (void);
1016
1017 /* Environment variable parsing */
1018
1019 #define MONO_GC_PARAMS_NAME     "MONO_GC_PARAMS"
1020 #define MONO_GC_DEBUG_NAME      "MONO_GC_DEBUG"
1021
1022 void sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...);
1023
1024 /* Utilities */
1025
1026 void sgen_qsort (void *base, size_t nel, size_t width, int (*compar) (const void*, const void*));
1027 gint64 sgen_timestamp (void);
1028
1029 /*
1030  * Canary (guard word) support
1031  * Notes:
1032  * - CANARY_SIZE must be multiple of word size in bytes
1033  * - Canary space is not included on checks against SGEN_MAX_SMALL_OBJ_SIZE
1034  */
1035
1036 gboolean nursery_canaries_enabled (void);
1037
1038 #define CANARY_SIZE 8
1039 #define CANARY_STRING  "koupepia"
1040
1041 #define CANARIFY_SIZE(size) if (nursery_canaries_enabled ()) {  \
1042                         size = size + CANARY_SIZE;      \
1043                 }
1044
1045 #define CANARIFY_ALLOC(addr,size) if (nursery_canaries_enabled ()) {    \
1046                                 memcpy ((char*) (addr) + (size), CANARY_STRING, CANARY_SIZE);   \
1047                         }
1048
1049 #define CANARY_VALID(addr) (strncmp ((char*) (addr), CANARY_STRING, CANARY_SIZE) == 0)
1050
1051 #define CHECK_CANARY_FOR_OBJECT(addr,fail) if (nursery_canaries_enabled ()) {   \
1052                                 char* canary_ptr = (char*) (addr) + sgen_safe_object_get_size_unaligned ((GCObject *) (addr));  \
1053                                 if (!CANARY_VALID(canary_ptr)) {        \
1054                                         char canary_copy[CANARY_SIZE +1];       \
1055                                         strncpy (canary_copy, canary_ptr, CANARY_SIZE); \
1056                                         canary_copy[CANARY_SIZE] = 0;   \
1057                                         if ((fail))                     \
1058                                                 g_error ("CORRUPT CANARY:\naddr->%p\ntype->%s\nexcepted->'%s'\nfound->'%s'\n", (char*) addr, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE ((addr))), CANARY_STRING, canary_copy); \
1059                                         else                            \
1060                                                 g_warning ("CORRUPT CANARY:\naddr->%p\ntype->%s\nexcepted->'%s'\nfound->'%s'\n", (char*) addr, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE ((addr))), CANARY_STRING, canary_copy); \
1061                                 } }
1062
1063 /*
1064  * This causes the compile to extend the liveness of 'v' till the call to dummy_use
1065  */
1066 static inline void
1067 sgen_dummy_use (gpointer v)
1068 {
1069 #if defined(__GNUC__)
1070         __asm__ volatile ("" : "=r"(v) : "r"(v));
1071 #elif defined(_MSC_VER)
1072         static volatile gpointer ptr;
1073         ptr = v;
1074 #else
1075 #error "Implement sgen_dummy_use for your compiler"
1076 #endif
1077 }
1078
1079 #endif /* HAVE_SGEN_GC */
1080
1081 #endif /* __MONO_SGENGC_H__ */