mono/metadata/boehm-gc.c

   1 /*
   2  * boehm-gc.c: GC implementation using either the installed or included Boehm GC.
   3  *
   4  * Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
   5  * Copyright 2004-2009 Novell, Inc (http://www.novell.com)
   6  */
   7
   8 #include "config.h"
   9 #define GC_I_HIDE_POINTERS
  10 #include <mono/metadata/gc-internal.h>
  11 #include <mono/metadata/mono-gc.h>
  12 #include <mono/metadata/gc-internal.h>
  13 #include <mono/metadata/profiler-private.h>
  14 #include <mono/metadata/class-internals.h>
  15 #include <mono/metadata/method-builder.h>
  16 #include <mono/metadata/opcodes.h>
  17 #include <mono/metadata/domain-internals.h>
  18 #include <mono/metadata/metadata-internals.h>
  19 #include <mono/utils/mono-logger.h>
  20 #include <mono/utils/mono-time.h>
  21 #include <mono/utils/dtrace.h>
  22
  23 #if HAVE_BOEHM_GC
  24
  25 #ifdef USE_INCLUDED_LIBGC
  26 #undef TRUE
  27 #undef FALSE
  28 #define THREAD_LOCAL_ALLOC 1
  29 #include "private/pthread_support.h"
  30 #endif
  31
  32 #define GC_NO_DESCRIPTOR ((gpointer)(0 | GC_DS_LENGTH))
  33
  34 static gboolean gc_initialized = FALSE;
  35
  36 static void
  37 mono_gc_warning (char *msg, GC_word arg)
  38 {
  39         mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_GC, msg, (unsigned long)arg);
  40 }
  41
  42 void
  43 mono_gc_base_init (void)
  44 {
  45         if (gc_initialized)
  46                 return;
  47
  48         /*
  49          * Handle the case when we are called from a thread different from the main thread,
  50          * confusing libgc.
  51          * FIXME: Move this to libgc where it belongs.
  52          *
  53          * we used to do this only when running on valgrind,
  54          * but it happens also in other setups.
  55          */
  56 #if defined(HAVE_PTHREAD_GETATTR_NP) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
  57         {
  58                 size_t size;
  59                 void *sstart;
  60                 pthread_attr_t attr;
  61                 pthread_getattr_np (pthread_self (), &attr);
  62                 pthread_attr_getstack (&attr, &sstart, &size);
  63                 pthread_attr_destroy (&attr);
  64                 /*g_print ("stackbottom pth is: %p\n", (char*)sstart + size);*/
  65 #ifdef __ia64__
  66                 /*
  67                  * The calculation above doesn't seem to work on ia64, also we need to set
  68                  * GC_register_stackbottom as well, but don't know how.
  69                  */
  70 #else
  71                 /* apparently with some linuxthreads implementations sstart can be NULL,
  72                  * fallback to the more imprecise method (bug# 78096).
  73                  */
  74                 if (sstart) {
  75                         GC_stackbottom = (char*)sstart + size;
  76                 } else {
  77                         int dummy;
  78                         gsize stack_bottom = (gsize)&dummy;
  79                         stack_bottom += 4095;
  80                         stack_bottom &= ~4095;
  81                         GC_stackbottom = (char*)stack_bottom;
  82                 }
  83 #endif
  84         }
  85 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
  86                 GC_stackbottom = (char*)pthread_get_stackaddr_np (pthread_self ());
  87 #else
  88         {
  89                 int dummy;
  90                 gsize stack_bottom = (gsize)&dummy;
  91                 stack_bottom += 4095;
  92                 stack_bottom &= ~4095;
  93                 /*g_print ("stackbottom is: %p\n", (char*)stack_bottom);*/
  94                 GC_stackbottom = (char*)stack_bottom;
  95         }
  96 #endif
  97
  98         GC_no_dls = TRUE;
  99         GC_init ();
 100         GC_oom_fn = mono_gc_out_of_memory;
 101         GC_set_warn_proc (mono_gc_warning);
 102         GC_finalize_on_demand = 1;
 103         GC_finalizer_notifier = mono_gc_finalize_notify;
 104
 105 #ifdef HAVE_GC_GCJ_MALLOC
 106         GC_init_gcj_malloc (5, NULL);
 107 #endif
 108         mono_gc_enable_events ();
 109         gc_initialized = TRUE;
 110 }
 111
 112 void
 113 mono_gc_collect (int generation)
 114 {
 115         MONO_PROBE_GC_BEGIN (generation);
 116
 117         mono_perfcounters->gc_induced++;
 118         GC_gcollect ();
 119
 120         MONO_PROBE_GC_END (generation);
 121 #if defined(ENABLE_DTRACE) && defined(__sun__)
 122         /* This works around a dtrace -G problem on Solaris.
 123            Limit its actual use to when the probe is enabled. */
 124         if (MONO_PROBE_GC_END_ENABLED ())
 125                 sleep(0);
 126 #endif
 127 }
 128
 129 int
 130 mono_gc_max_generation (void)
 131 {
 132         return 0;
 133 }
 134
 135 int
 136 mono_gc_get_generation  (MonoObject *object)
 137 {
 138         return 0;
 139 }
 140
 141 int
 142 mono_gc_collection_count (int generation)
 143 {
 144         return GC_gc_no;
 145 }
 146
 147 void
 148 mono_gc_add_memory_pressure (gint64 value)
 149 {
 150 }
 151
 152 gint64
 153 mono_gc_get_used_size (void)
 154 {
 155         return GC_get_heap_size () - GC_get_free_bytes ();
 156 }
 157
 158 gint64
 159 mono_gc_get_heap_size (void)
 160 {
 161         return GC_get_heap_size ();
 162 }
 163
 164 void
 165 mono_gc_disable (void)
 166 {
 167 #ifdef HAVE_GC_ENABLE
 168         GC_disable ();
 169 #else
 170         g_assert_not_reached ();
 171 #endif
 172 }
 173
 174 void
 175 mono_gc_enable (void)
 176 {
 177 #ifdef HAVE_GC_ENABLE
 178         GC_enable ();
 179 #else
 180         g_assert_not_reached ();
 181 #endif
 182 }
 183
 184 gboolean
 185 mono_gc_is_gc_thread (void)
 186 {
 187 #if GC_VERSION_MAJOR >= 7
 188         return TRUE;
 189 #elif defined(USE_INCLUDED_LIBGC)
 190         return GC_thread_is_registered ();
 191 #else
 192         return TRUE;
 193 #endif
 194 }
 195
 196 extern int GC_thread_register_foreign (void *base_addr);
 197
 198 gboolean
 199 mono_gc_register_thread (void *baseptr)
 200 {
 201 #if GC_VERSION_MAJOR >= 7
 202         struct GC_stack_base sb;
 203         int res;
 204
 205         res = GC_get_stack_base (&sb);
 206         if (res != GC_SUCCESS) {
 207                 sb.mem_base = baseptr;
 208 #ifdef __ia64__
 209                 /* Can't determine the register stack bounds */
 210                 g_error ("mono_gc_register_thread failed ().\n");
 211 #endif
 212         }
 213         res = GC_register_my_thread (&sb);
 214         if ((res != GC_SUCCESS) && (res != GC_DUPLICATE)) {
 215                 g_warning ("GC_register_my_thread () failed.\n");
 216                 return FALSE;
 217         }
 218         return TRUE;
 219 #else
 220         if (mono_gc_is_gc_thread())
 221                 return TRUE;
 222 #if defined(USE_INCLUDED_LIBGC) && !defined(PLATFORM_WIN32)
 223         return GC_thread_register_foreign (baseptr);
 224 #else
 225         return FALSE;
 226 #endif
 227 #endif
 228 }
 229
 230 gboolean
 231 mono_object_is_alive (MonoObject* o)
 232 {
 233 #ifdef USE_INCLUDED_LIBGC
 234         return GC_is_marked ((gpointer)o);
 235 #else
 236         return TRUE;
 237 #endif
 238 }
 239
 240 #ifdef USE_INCLUDED_LIBGC
 241
 242 static gint64 gc_start_time;
 243
 244 static void
 245 on_gc_notification (GCEventType event)
 246 {
 247         if (event == MONO_GC_EVENT_START) {
 248                 mono_perfcounters->gc_collections0++;
 249                 mono_stats.major_gc_count ++;
 250                 gc_start_time = mono_100ns_ticks ();
 251         } else if (event == MONO_GC_EVENT_END) {
 252                 guint64 heap_size = GC_get_heap_size ();
 253                 guint64 used_size = heap_size - GC_get_free_bytes ();
 254                 mono_perfcounters->gc_total_bytes = used_size;
 255                 mono_perfcounters->gc_committed_bytes = heap_size;
 256                 mono_perfcounters->gc_reserved_bytes = heap_size;
 257                 mono_perfcounters->gc_gen0size = heap_size;
 258                 mono_stats.major_gc_time_usecs += (mono_100ns_ticks () - gc_start_time) / 10;
 259                 mono_trace_message (MONO_TRACE_GC, "gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
 260         }
 261         mono_profiler_gc_event ((MonoGCEvent) event, 0);
 262 }
 263
 264 static void
 265 on_gc_heap_resize (size_t new_size)
 266 {
 267         guint64 heap_size = GC_get_heap_size ();
 268         mono_perfcounters->gc_committed_bytes = heap_size;
 269         mono_perfcounters->gc_reserved_bytes = heap_size;
 270         mono_perfcounters->gc_gen0size = heap_size;
 271         mono_profiler_gc_heap_resize (new_size);
 272 }
 273
 274 void
 275 mono_gc_enable_events (void)
 276 {
 277         GC_notify_event = on_gc_notification;
 278         GC_on_heap_resize = on_gc_heap_resize;
 279 }
 280
 281 #else
 282
 283 void
 284 mono_gc_enable_events (void)
 285 {
 286 }
 287
 288 #endif
 289
 290 int
 291 mono_gc_register_root (char *start, size_t size, void *descr)
 292 {
 293         /* for some strange reason, they want one extra byte on the end */
 294         GC_add_roots (start, start + size + 1);
 295
 296         return TRUE;
 297 }
 298
 299 void
 300 mono_gc_deregister_root (char* addr)
 301 {
 302 #ifndef PLATFORM_WIN32
 303         /* FIXME: libgc doesn't define this work win32 for some reason */
 304         /* FIXME: No size info */
 305         GC_remove_roots (addr, addr + sizeof (gpointer) + 1);
 306 #endif
 307 }
 308
 309 void
 310 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
 311 {
 312         /* libgc requires that we use HIDE_POINTER... */
 313         *link_addr = (void*)HIDE_POINTER (obj);
 314         GC_GENERAL_REGISTER_DISAPPEARING_LINK (link_addr, obj);
 315 }
 316
 317 void
 318 mono_gc_weak_link_remove (void **link_addr)
 319 {
 320         GC_unregister_disappearing_link (link_addr);
 321         *link_addr = NULL;
 322 }
 323
 324 MonoObject*
 325 mono_gc_weak_link_get (void **link_addr)
 326 {
 327         MonoObject *obj = REVEAL_POINTER (*link_addr);
 328         if (obj == (MonoObject *) -1)
 329                 return NULL;
 330         return obj;
 331 }
 332
 333 void*
 334 mono_gc_make_descr_for_string (gsize *bitmap, int numbits)
 335 {
 336         return mono_gc_make_descr_from_bitmap (bitmap, numbits);
 337 }
 338
 339 void*
 340 mono_gc_make_descr_for_object (gsize *bitmap, int numbits, size_t obj_size)
 341 {
 342         return mono_gc_make_descr_from_bitmap (bitmap, numbits);
 343 }
 344
 345 void*
 346 mono_gc_make_descr_for_array (int vector, gsize *elem_bitmap, int numbits, size_t elem_size)
 347 {
 348         /* libgc has no usable support for arrays... */
 349         return GC_NO_DESCRIPTOR;
 350 }
 351
 352 void*
 353 mono_gc_make_descr_from_bitmap (gsize *bitmap, int numbits)
 354 {
 355 #ifdef HAVE_GC_GCJ_MALLOC
 356         /* It seems there are issues when the bitmap doesn't fit: play it safe */
 357         if (numbits >= 30)
 358                 return GC_NO_DESCRIPTOR;
 359         else
 360                 return (gpointer)GC_make_descriptor ((GC_bitmap)bitmap, numbits);
 361 #else
 362         return NULL;
 363 #endif
 364 }
 365
 366 void*
 367 mono_gc_alloc_fixed (size_t size, void *descr)
 368 {
 369         /* To help track down typed allocation bugs */
 370         /*
 371         static int count;
 372         count ++;
 373         if (count == atoi (getenv ("COUNT2")))
 374                 printf ("HIT!\n");
 375         if (count > atoi (getenv ("COUNT2")))
 376                 return GC_MALLOC (size);
 377         */
 378
 379         if (descr)
 380                 return GC_MALLOC_EXPLICITLY_TYPED (size, (GC_descr)descr);
 381         else
 382                 return GC_MALLOC (size);
 383 }
 384
 385 void
 386 mono_gc_free_fixed (void* addr)
 387 {
 388 }
 389
 390 int
 391 mono_gc_invoke_finalizers (void)
 392 {
 393         /* There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
 394          * the 'mem_freed' variable is not initialized when there are no
 395          * objects to finalize, which leads to strange behavior later on.
 396          * The check is necessary to work around that bug.
 397          */
 398         if (GC_should_invoke_finalizers ())
 399                 return GC_invoke_finalizers ();
 400         return 0;
 401 }
 402
 403 gboolean
 404 mono_gc_pending_finalizers (void)
 405 {
 406         return GC_should_invoke_finalizers ();
 407 }
 408
 409 /*
 410  * LOCKING: Assumes the domain_finalizers lock is held.
 411  */
 412 static void
 413 add_weak_track_handle_internal (MonoDomain *domain, MonoObject *obj, guint32 gchandle)
 414 {
 415         GSList *refs;
 416
 417         if (!domain->track_resurrection_objects_hash)
 418                 domain->track_resurrection_objects_hash = g_hash_table_new (mono_aligned_addr_hash, NULL);
 419
 420         refs = g_hash_table_lookup (domain->track_resurrection_objects_hash, obj);
 421         refs = g_slist_prepend (refs, GUINT_TO_POINTER (gchandle));
 422         g_hash_table_insert (domain->track_resurrection_objects_hash, obj, refs);
 423 }
 424
 425 void
 426 mono_gc_add_weak_track_handle (MonoObject *obj, guint32 handle)
 427 {
 428         MonoDomain *domain = mono_domain_get ();
 429
 430         mono_domain_finalizers_lock (domain);
 431
 432         add_weak_track_handle_internal (domain, obj, handle);
 433
 434         g_hash_table_insert (domain->track_resurrection_handles_hash, GUINT_TO_POINTER (handle), obj);
 435
 436         mono_domain_finalizers_unlock (domain);
 437 }
 438
 439 /*
 440  * LOCKING: Assumes the domain_finalizers lock is held.
 441  */
 442 static void
 443 remove_weak_track_handle_internal (MonoDomain *domain, MonoObject *obj, guint32 gchandle)
 444 {
 445         GSList *refs;
 446
 447         if (!domain->track_resurrection_objects_hash)
 448                 return;
 449
 450         refs = g_hash_table_lookup (domain->track_resurrection_objects_hash, obj);
 451         refs = g_slist_remove (refs, GUINT_TO_POINTER (gchandle));
 452         g_hash_table_insert (domain->track_resurrection_objects_hash, obj, refs);
 453 }
 454
 455 void
 456 mono_gc_change_weak_track_handle (MonoObject *old_obj, MonoObject *obj, guint32 gchandle)
 457 {
 458         MonoDomain *domain = mono_domain_get ();
 459
 460         mono_domain_finalizers_lock (domain);
 461
 462         if (old_obj)
 463                 remove_weak_track_handle_internal (domain, old_obj, gchandle);
 464         if (obj)
 465                 add_weak_track_handle_internal (domain, obj, gchandle);
 466
 467         mono_domain_finalizers_unlock (domain);
 468 }
 469
 470 void
 471 mono_gc_remove_weak_track_handle (guint32 gchandle)
 472 {
 473         MonoDomain *domain = mono_domain_get ();
 474         MonoObject *obj;
 475
 476         /* Clean our entries in the two hashes in MonoDomain */
 477
 478         mono_domain_finalizers_lock (domain);
 479
 480         /* Get the original object this handle pointed to */
 481         obj = g_hash_table_lookup (domain->track_resurrection_handles_hash, GUINT_TO_POINTER (gchandle));
 482         if (obj) {
 483                 g_hash_table_remove (domain->track_resurrection_handles_hash, GUINT_TO_POINTER (gchandle));
 484
 485                 remove_weak_track_handle_internal (domain, obj, gchandle);
 486         }
 487
 488         mono_domain_finalizers_unlock (domain);
 489 }
 490
 491 GSList*
 492 mono_gc_remove_weak_track_object (MonoDomain *domain, MonoObject *obj)
 493 {
 494         GSList *refs = NULL;
 495
 496         if (domain->track_resurrection_objects_hash) {
 497                 refs = g_hash_table_lookup (domain->track_resurrection_objects_hash, obj);
 498
 499                 if (refs)
 500                         /*
 501                          * Since we don't run finalizers again for resurrected objects,
 502                          * no need to keep these around.
 503                          */
 504                         g_hash_table_remove (domain->track_resurrection_objects_hash, obj);
 505         }
 506
 507         return refs;
 508 }
 509
 510 void
 511 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
 512 {
 513         *(void**)field_ptr = value;
 514 }
 515
 516 void
 517 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
 518 {
 519         *(void**)slot_ptr = value;
 520 }
 521
 522 void
 523 mono_gc_wbarrier_arrayref_copy (MonoArray *arr, gpointer slot_ptr, int count)
 524 {
 525         /* no need to do anything */
 526 }
 527
 528 void
 529 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
 530 {
 531         *(void**)ptr = value;
 532 }
 533
 534 void
 535 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
 536 {
 537 }
 538
 539 void
 540 mono_gc_wbarrier_object (MonoObject *object)
 541 {
 542 }
 543
 544 #if defined(USE_INCLUDED_LIBGC) && defined(USE_COMPILER_TLS) && defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
 545 extern __thread MONO_TLS_FAST void* GC_thread_tls;
 546 #include "metadata-internals.h"
 547
 548 static int
 549 shift_amount (int v)
 550 {
 551         int i = 0;
 552         while (!(v & (1 << i)))
 553                 i++;
 554         return i;
 555 }
 556
 557 enum {
 558         ATYPE_FREEPTR,
 559         ATYPE_FREEPTR_FOR_BOX,
 560         ATYPE_NORMAL,
 561         ATYPE_GCJ,
 562         ATYPE_STRING,
 563         ATYPE_NUM
 564 };
 565
 566 static MonoMethod*
 567 create_allocator (int atype, int offset)
 568 {
 569         int index_var, bytes_var, my_fl_var, my_entry_var;
 570         guint32 no_freelist_branch, not_small_enough_branch = 0;
 571         guint32 size_overflow_branch = 0;
 572         MonoMethodBuilder *mb;
 573         MonoMethod *res;
 574         MonoMethodSignature *csig;
 575
 576         if (atype == ATYPE_STRING) {
 577                 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 2);
 578                 csig->ret = &mono_defaults.string_class->byval_arg;
 579                 csig->params [0] = &mono_defaults.int_class->byval_arg;
 580                 csig->params [1] = &mono_defaults.int32_class->byval_arg;
 581         } else {
 582                 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
 583                 csig->ret = &mono_defaults.object_class->byval_arg;
 584                 csig->params [0] = &mono_defaults.int_class->byval_arg;
 585         }
 586
 587         mb = mono_mb_new (mono_defaults.object_class, "Alloc", MONO_WRAPPER_ALLOC);
 588         bytes_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
 589         if (atype == ATYPE_STRING) {
 590                 /* a string alloator method takes the args: (vtable, len) */
 591                 /* bytes = (sizeof (MonoString) + ((len + 1) * 2)); */
 592                 mono_mb_emit_ldarg (mb, 1);
 593                 mono_mb_emit_icon (mb, 1);
 594                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 595                 mono_mb_emit_icon (mb, 1);
 596                 mono_mb_emit_byte (mb, MONO_CEE_SHL);
 597                 // sizeof (MonoString) might include padding
 598                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, chars));
 599                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 600                 mono_mb_emit_stloc (mb, bytes_var);
 601         } else {
 602                 /* bytes = vtable->klass->instance_size */
 603                 mono_mb_emit_ldarg (mb, 0);
 604                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
 605                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 606                 mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 607                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, instance_size));
 608                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 609                 /* FIXME: assert instance_size stays a 4 byte integer */
 610                 mono_mb_emit_byte (mb, MONO_CEE_LDIND_U4);
 611                 mono_mb_emit_stloc (mb, bytes_var);
 612         }
 613
 614         /* this is needed for strings/arrays only as the other big types are never allocated with this method */
 615         if (atype == ATYPE_STRING) {
 616                 /* check for size */
 617                 /* if (!SMALL_ENOUGH (bytes)) jump slow_path;*/
 618                 mono_mb_emit_ldloc (mb, bytes_var);
 619                 mono_mb_emit_icon (mb, (NFREELISTS-1) * GRANULARITY);
 620                 not_small_enough_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
 621                 /* check for overflow */
 622                 mono_mb_emit_ldloc (mb, bytes_var);
 623                 mono_mb_emit_icon (mb, sizeof (MonoString));
 624                 size_overflow_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
 625         }
 626
 627         /* int index = INDEX_FROM_BYTES(bytes); */
 628         index_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
 629
 630         mono_mb_emit_ldloc (mb, bytes_var);
 631         mono_mb_emit_icon (mb, GRANULARITY - 1);
 632         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 633         mono_mb_emit_icon (mb, shift_amount (GRANULARITY));
 634         mono_mb_emit_byte (mb, MONO_CEE_SHR_UN);
 635         mono_mb_emit_icon (mb, shift_amount (sizeof (gpointer)));
 636         mono_mb_emit_byte (mb, MONO_CEE_SHL);
 637         /* index var is already adjusted into bytes */
 638         mono_mb_emit_stloc (mb, index_var);
 639
 640         my_fl_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 641         my_entry_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 642         /* my_fl = ((GC_thread)tsd) -> ptrfree_freelists + index; */
 643         mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
 644         mono_mb_emit_byte (mb, 0x0D); /* CEE_MONO_TLS */
 645         mono_mb_emit_i4 (mb, offset);
 646         if (atype == ATYPE_FREEPTR || atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING)
 647                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, ptrfree_freelists));
 648         else if (atype == ATYPE_NORMAL)
 649                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, normal_freelists));
 650         else if (atype == ATYPE_GCJ)
 651                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, gcj_freelists));
 652         else
 653                 g_assert_not_reached ();
 654         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 655         mono_mb_emit_ldloc (mb, index_var);
 656         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 657         mono_mb_emit_stloc (mb, my_fl_var);
 658
 659         /* my_entry = *my_fl; */
 660         mono_mb_emit_ldloc (mb, my_fl_var);
 661         mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 662         mono_mb_emit_stloc (mb, my_entry_var);
 663
 664         /* if (EXPECT((word)my_entry >= HBLKSIZE, 1)) { */
 665         mono_mb_emit_ldloc (mb, my_entry_var);
 666         mono_mb_emit_icon (mb, HBLKSIZE);
 667         no_freelist_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
 668
 669         /* ptr_t next = obj_link(my_entry); *my_fl = next; */
 670         mono_mb_emit_ldloc (mb, my_fl_var);
 671         mono_mb_emit_ldloc (mb, my_entry_var);
 672         mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 673         mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 674
 675         /* set the vtable and clear the words in the object */
 676         mono_mb_emit_ldloc (mb, my_entry_var);
 677         mono_mb_emit_ldarg (mb, 0);
 678         mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 679
 680         if (atype == ATYPE_FREEPTR) {
 681                 int start_var, end_var, start_loop;
 682                 /* end = my_entry + bytes; start = my_entry + sizeof (gpointer);
 683                  */
 684                 start_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 685                 end_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 686                 mono_mb_emit_ldloc (mb, my_entry_var);
 687                 mono_mb_emit_ldloc (mb, bytes_var);
 688                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 689                 mono_mb_emit_stloc (mb, end_var);
 690                 mono_mb_emit_ldloc (mb, my_entry_var);
 691                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
 692                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 693                 mono_mb_emit_stloc (mb, start_var);
 694                 /*
 695                  * do {
 696                  *      *start++ = NULL;
 697                  * } while (start < end);
 698                  */
 699                 start_loop = mono_mb_get_label (mb);
 700                 mono_mb_emit_ldloc (mb, start_var);
 701                 mono_mb_emit_icon (mb, 0);
 702                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 703                 mono_mb_emit_ldloc (mb, start_var);
 704                 mono_mb_emit_icon (mb, sizeof (gpointer));
 705                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 706                 mono_mb_emit_stloc (mb, start_var);
 707
 708                 mono_mb_emit_ldloc (mb, start_var);
 709                 mono_mb_emit_ldloc (mb, end_var);
 710                 mono_mb_emit_byte (mb, MONO_CEE_BLT_UN_S);
 711                 mono_mb_emit_byte (mb, start_loop - (mono_mb_get_label (mb) + 1));
 712         } else if (atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING) {
 713                 /* need to clear just the sync pointer */
 714                 mono_mb_emit_ldloc (mb, my_entry_var);
 715                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
 716                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 717                 mono_mb_emit_icon (mb, 0);
 718                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 719         }
 720
 721         if (atype == ATYPE_STRING) {
 722                 /* need to set length and clear the last char */
 723                 /* s->length = len; */
 724                 mono_mb_emit_ldloc (mb, my_entry_var);
 725                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, length));
 726                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 727                 mono_mb_emit_ldarg (mb, 1);
 728                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
 729                 /* s->chars [len] = 0; */
 730                 mono_mb_emit_ldloc (mb, my_entry_var);
 731                 mono_mb_emit_ldloc (mb, bytes_var);
 732                 mono_mb_emit_icon (mb, 2);
 733                 mono_mb_emit_byte (mb, MONO_CEE_SUB);
 734                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 735                 mono_mb_emit_icon (mb, 0);
 736                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
 737         }
 738
 739         /* return my_entry; */
 740         mono_mb_emit_ldloc (mb, my_entry_var);
 741         mono_mb_emit_byte (mb, MONO_CEE_RET);
 742
 743         mono_mb_patch_short_branch (mb, no_freelist_branch);
 744         if (not_small_enough_branch > 0)
 745                 mono_mb_patch_short_branch (mb, not_small_enough_branch);
 746         if (size_overflow_branch > 0)
 747                 mono_mb_patch_short_branch (mb, size_overflow_branch);
 748         /* the slow path: we just call back into the runtime */
 749         if (atype == ATYPE_STRING) {
 750                 mono_mb_emit_ldarg (mb, 1);
 751                 mono_mb_emit_icall (mb, mono_string_alloc);
 752         } else {
 753                 mono_mb_emit_ldarg (mb, 0);
 754                 mono_mb_emit_icall (mb, mono_object_new_specific);
 755         }
 756
 757         mono_mb_emit_byte (mb, MONO_CEE_RET);
 758
 759         res = mono_mb_create_method (mb, csig, 8);
 760         mono_mb_free (mb);
 761         mono_method_get_header (res)->init_locals = FALSE;
 762         return res;
 763 }
 764
 765 static MonoMethod* alloc_method_cache [ATYPE_NUM];
 766
 767 /*
 768  * If possible, generate a managed method that can quickly allocate objects in class
 769  * @klass. The method will typically have an thread-local inline allocation sequence.
 770  * The signature of the called method is:
 771  *      object allocate (MonoVTable *vtable)
 772  * Some of the logic here is similar to mono_class_get_allocation_ftn () i object.c,
 773  * keep in sync.
 774  * The thread local alloc logic is taken from libgc/pthread_support.c.
 775  */
 776
 777 MonoMethod*
 778 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
 779 {
 780         int offset = -1;
 781         int atype;
 782         MonoClass *klass = vtable->klass;
 783         MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
 784
 785         /*g_print ("thread tls: %d\n", offset);*/
 786         if (offset == -1)
 787                 return NULL;
 788         if (!SMALL_ENOUGH (klass->instance_size))
 789                 return NULL;
 790         if (klass->has_finalize || klass->marshalbyref || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
 791                 return NULL;
 792         if (klass->rank)
 793                 return NULL;
 794         if (klass->byval_arg.type == MONO_TYPE_STRING) {
 795                 atype = ATYPE_STRING;
 796         } else if (!klass->has_references) {
 797                 if (for_box)
 798                         atype = ATYPE_FREEPTR_FOR_BOX;
 799                 else
 800                         atype = ATYPE_FREEPTR;
 801         } else {
 802                 return NULL;
 803                 /*
 804                  * disabled because we currently do a runtime choice anyway, to
 805                  * deal with multiple appdomains.
 806                 if (vtable->gc_descr != GC_NO_DESCRIPTOR)
 807                         atype = ATYPE_GCJ;
 808                 else
 809                         atype = ATYPE_NORMAL;
 810                 */
 811         }
 812         return mono_gc_get_managed_allocator_by_type (atype);
 813 }
 814
 815 /**
 816  * mono_gc_get_managed_allocator_id:
 817  *
 818  *   Return a type for the managed allocator method MANAGED_ALLOC which can later be passed
 819  * to mono_gc_get_managed_allocator_by_type () to get back this allocator method. This can be
 820  * used by the AOT code to encode references to managed allocator methods.
 821  */
 822 int
 823 mono_gc_get_managed_allocator_type (MonoMethod *managed_alloc)
 824 {
 825         int i;
 826
 827         mono_loader_lock ();
 828         for (i = 0; i < ATYPE_NUM; ++i) {
 829                 if (alloc_method_cache [i] == managed_alloc) {
 830                         mono_loader_unlock ();
 831                         return i;
 832                 }
 833         }
 834         mono_loader_unlock ();
 835
 836         return -1;
 837 }
 838
 839 /**
 840  * mono_gc_get_managed_allocator_by_type:
 841  *
 842  *   Return a managed allocator method corresponding to allocator type ATYPE.
 843  */
 844 MonoMethod*
 845 mono_gc_get_managed_allocator_by_type (int atype)
 846 {
 847         int offset = -1;
 848         MonoMethod *res;
 849         MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
 850
 851         mono_loader_lock ();
 852         res = alloc_method_cache [atype];
 853         if (!res)
 854                 res = alloc_method_cache [atype] = create_allocator (atype, offset);
 855         mono_loader_unlock ();
 856         return res;
 857 }
 858
 859 guint32
 860 mono_gc_get_managed_allocator_types (void)
 861 {
 862         return ATYPE_NUM;
 863 }
 864
 865 #else
 866
 867 MonoMethod*
 868 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
 869 {
 870         return NULL;
 871 }
 872
 873 int
 874 mono_gc_get_managed_allocator_type (MonoMethod *managed_alloc)
 875 {
 876         return -1;
 877 }
 878
 879 MonoMethod*
 880 mono_gc_get_managed_allocator_by_type (int atype)
 881 {
 882         return NULL;
 883 }
 884
 885 guint32
 886 mono_gc_get_managed_allocator_types (void)
 887 {
 888         return 0;
 889 }
 890
 891 #endif
 892
 893 #endif /* no Boehm GC */
 894