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