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 2004-2011 Novell, Inc (http://www.novell.com)
   6  * Copyright 2011-2012 Xamarin, Inc (http://www.xamarin.com)
   7  */
   8
   9 #include "config.h"
  10
  11 #include <string.h>
  12
  13 #define GC_I_HIDE_POINTERS
  14 #include <mono/metadata/gc-internal.h>
  15 #include <mono/metadata/mono-gc.h>
  16 #include <mono/metadata/gc-internal.h>
  17 #include <mono/metadata/profiler-private.h>
  18 #include <mono/metadata/class-internals.h>
  19 #include <mono/metadata/method-builder.h>
  20 #include <mono/metadata/opcodes.h>
  21 #include <mono/metadata/domain-internals.h>
  22 #include <mono/metadata/metadata-internals.h>
  23 #include <mono/metadata/marshal.h>
  24 #include <mono/metadata/runtime.h>
  25 #include <mono/utils/mono-logger-internal.h>
  26 #include <mono/utils/mono-time.h>
  27 #include <mono/utils/mono-threads.h>
  28 #include <mono/utils/dtrace.h>
  29 #include <mono/utils/gc_wrapper.h>
  30
  31 #if HAVE_BOEHM_GC
  32
  33 #ifdef USE_INCLUDED_LIBGC
  34 #undef TRUE
  35 #undef FALSE
  36 #define THREAD_LOCAL_ALLOC 1
  37 #include "private/pthread_support.h"
  38 #endif
  39
  40 #if defined(PLATFORM_MACOSX) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
  41 void *pthread_get_stackaddr_np(pthread_t);
  42 #endif
  43
  44 #define GC_NO_DESCRIPTOR ((gpointer)(0 | GC_DS_LENGTH))
  45 /*Boehm max heap cannot be smaller than 16MB*/
  46 #define MIN_BOEHM_MAX_HEAP_SIZE_IN_MB 16
  47 #define MIN_BOEHM_MAX_HEAP_SIZE (MIN_BOEHM_MAX_HEAP_SIZE_IN_MB << 20)
  48
  49 static gboolean gc_initialized = FALSE;
  50
  51 static void*
  52 boehm_thread_register (MonoThreadInfo* info, void *baseptr);
  53
  54 static void
  55 mono_gc_warning (char *msg, GC_word arg)
  56 {
  57         mono_trace (G_LOG_LEVEL_WARNING, MONO_TRACE_GC, msg, (unsigned long)arg);
  58 }
  59
  60 void
  61 mono_gc_base_init (void)
  62 {
  63         MonoThreadInfoCallbacks cb;
  64         char *env;
  65
  66         if (gc_initialized)
  67                 return;
  68
  69         /*
  70          * Handle the case when we are called from a thread different from the main thread,
  71          * confusing libgc.
  72          * FIXME: Move this to libgc where it belongs.
  73          *
  74          * we used to do this only when running on valgrind,
  75          * but it happens also in other setups.
  76          */
  77 #if defined(HAVE_PTHREAD_GETATTR_NP) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
  78         {
  79                 size_t size;
  80                 void *sstart;
  81                 pthread_attr_t attr;
  82                 pthread_getattr_np (pthread_self (), &attr);
  83                 pthread_attr_getstack (&attr, &sstart, &size);
  84                 pthread_attr_destroy (&attr);
  85                 /*g_print ("stackbottom pth is: %p\n", (char*)sstart + size);*/
  86 #ifdef __ia64__
  87                 /*
  88                  * The calculation above doesn't seem to work on ia64, also we need to set
  89                  * GC_register_stackbottom as well, but don't know how.
  90                  */
  91 #else
  92                 /* apparently with some linuxthreads implementations sstart can be NULL,
  93                  * fallback to the more imprecise method (bug# 78096).
  94                  */
  95                 if (sstart) {
  96                         GC_stackbottom = (char*)sstart + size;
  97                 } else {
  98                         int dummy;
  99                         gsize stack_bottom = (gsize)&dummy;
 100                         stack_bottom += 4095;
 101                         stack_bottom &= ~4095;
 102                         GC_stackbottom = (char*)stack_bottom;
 103                 }
 104 #endif
 105         }
 106 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
 107                 GC_stackbottom = (char*)pthread_get_stackaddr_np (pthread_self ());
 108 #elif defined(__OpenBSD__)
 109 #  include <pthread_np.h>
 110         {
 111                 stack_t ss;
 112                 int rslt;
 113
 114                 rslt = pthread_stackseg_np(pthread_self(), &ss);
 115                 g_assert (rslt == 0);
 116
 117                 GC_stackbottom = (char*)ss.ss_sp;
 118         }
 119 #elif defined(__native_client__)
 120         /* Do nothing, GC_stackbottom is set correctly in libgc */
 121 #else
 122         {
 123                 int dummy;
 124                 gsize stack_bottom = (gsize)&dummy;
 125                 stack_bottom += 4095;
 126                 stack_bottom &= ~4095;
 127                 /*g_print ("stackbottom is: %p\n", (char*)stack_bottom);*/
 128                 GC_stackbottom = (char*)stack_bottom;
 129         }
 130 #endif
 131
 132 #if !defined(PLATFORM_ANDROID)
 133         /* If GC_no_dls is set to true, GC_find_limit is not called. This causes a seg fault on Android. */
 134         GC_no_dls = TRUE;
 135 #endif
 136         GC_init ();
 137         GC_oom_fn = mono_gc_out_of_memory;
 138         GC_set_warn_proc (mono_gc_warning);
 139         GC_finalize_on_demand = 1;
 140         GC_finalizer_notifier = mono_gc_finalize_notify;
 141
 142 #ifdef HAVE_GC_GCJ_MALLOC
 143         GC_init_gcj_malloc (5, NULL);
 144 #endif
 145
 146 #ifdef HAVE_GC_ALLOW_REGISTER_THREADS
 147         GC_allow_register_threads();
 148 #endif
 149
 150         if ((env = getenv ("MONO_GC_PARAMS"))) {
 151                 char **ptr, **opts = g_strsplit (env, ",", -1);
 152                 for (ptr = opts; *ptr; ++ptr) {
 153                         char *opt = *ptr;
 154                         if (g_str_has_prefix (opt, "max-heap-size=")) {
 155                                 glong max_heap;
 156
 157                                 opt = strchr (opt, '=') + 1;
 158                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap)) {
 159                                         if (max_heap < MIN_BOEHM_MAX_HEAP_SIZE) {
 160                                                 fprintf (stderr, "max-heap-size must be at least %dMb.\n", MIN_BOEHM_MAX_HEAP_SIZE_IN_MB);
 161                                                 exit (1);
 162                                         }
 163                                         GC_set_max_heap_size (max_heap);
 164                                 } else {
 165                                         fprintf (stderr, "max-heap-size must be an integer.\n");
 166                                         exit (1);
 167                                 }
 168                                 continue;
 169                         } else {
 170                                 /* Could be a parameter for sgen */
 171                                 /*
 172                                 fprintf (stderr, "MONO_GC_PARAMS must be a comma-delimited list of one or more of the following:\n");
 173                                 fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
 174                                 exit (1);
 175                                 */
 176                         }
 177                 }
 178                 g_strfreev (opts);
 179         }
 180
 181         memset (&cb, 0, sizeof (cb));
 182         cb.thread_register = boehm_thread_register;
 183         cb.mono_method_is_critical = (gpointer)mono_runtime_is_critical_method;
 184 #ifndef HOST_WIN32
 185         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
 186 #endif
 187
 188         mono_threads_init (&cb, sizeof (MonoThreadInfo));
 189
 190         mono_gc_enable_events ();
 191         gc_initialized = TRUE;
 192 }
 193
 194 /**
 195  * mono_gc_collect:
 196  * @generation: GC generation identifier
 197  *
 198  * Perform a garbage collection for the given generation, higher numbers
 199  * mean usually older objects. Collecting a high-numbered generation
 200  * implies collecting also the lower-numbered generations.
 201  * The maximum value for @generation can be retrieved with a call to
 202  * mono_gc_max_generation(), so this function is usually called as:
 203  *
 204  *      mono_gc_collect (mono_gc_max_generation ());
 205  */
 206 void
 207 mono_gc_collect (int generation)
 208 {
 209 #ifndef DISABLE_PERFCOUNTERS
 210         mono_perfcounters->gc_induced++;
 211 #endif
 212         GC_gcollect ();
 213 }
 214
 215 /**
 216  * mono_gc_max_generation:
 217  *
 218  * Get the maximum generation number used by the current garbage
 219  * collector. The value will be 0 for the Boehm collector, 1 or more
 220  * for the generational collectors.
 221  *
 222  * Returns: the maximum generation number.
 223  */
 224 int
 225 mono_gc_max_generation (void)
 226 {
 227         return 0;
 228 }
 229
 230 /**
 231  * mono_gc_get_generation:
 232  * @object: a managed object
 233  *
 234  * Get the garbage collector's generation that @object belongs to.
 235  * Use this has a hint only.
 236  *
 237  * Returns: a garbage collector generation number
 238  */
 239 int
 240 mono_gc_get_generation  (MonoObject *object)
 241 {
 242         return 0;
 243 }
 244
 245 /**
 246  * mono_gc_collection_count:
 247  * @generation: a GC generation number
 248  *
 249  * Get how many times a garbage collection has been performed
 250  * for the given @generation number.
 251  *
 252  * Returns: the number of garbage collections
 253  */
 254 int
 255 mono_gc_collection_count (int generation)
 256 {
 257         return GC_gc_no;
 258 }
 259
 260 /**
 261  * mono_gc_add_memory_pressure:
 262  * @value: amount of bytes
 263  *
 264  * Adjust the garbage collector's view of how many bytes of memory
 265  * are indirectly referenced by managed objects (for example unmanaged
 266  * memory holding image or other binary data).
 267  * This is a hint only to the garbage collector algorithm.
 268  * Note that negative amounts of @value will decrease the memory
 269  * pressure.
 270  */
 271 void
 272 mono_gc_add_memory_pressure (gint64 value)
 273 {
 274 }
 275
 276 /**
 277  * mono_gc_get_used_size:
 278  *
 279  * Get the approximate amount of memory used by managed objects.
 280  *
 281  * Returns: the amount of memory used in bytes
 282  */
 283 int64_t
 284 mono_gc_get_used_size (void)
 285 {
 286         return GC_get_heap_size () - GC_get_free_bytes ();
 287 }
 288
 289 /**
 290  * mono_gc_get_heap_size:
 291  *
 292  * Get the amount of memory used by the garbage collector.
 293  *
 294  * Returns: the size of the heap in bytes
 295  */
 296 int64_t
 297 mono_gc_get_heap_size (void)
 298 {
 299         return GC_get_heap_size ();
 300 }
 301
 302 void
 303 mono_gc_disable (void)
 304 {
 305 #ifdef HAVE_GC_ENABLE
 306         GC_disable ();
 307 #else
 308         g_assert_not_reached ();
 309 #endif
 310 }
 311
 312 void
 313 mono_gc_enable (void)
 314 {
 315 #ifdef HAVE_GC_ENABLE
 316         GC_enable ();
 317 #else
 318         g_assert_not_reached ();
 319 #endif
 320 }
 321
 322 gboolean
 323 mono_gc_is_gc_thread (void)
 324 {
 325 #if GC_VERSION_MAJOR >= 7
 326         return TRUE;
 327 #elif defined(USE_INCLUDED_LIBGC)
 328         return GC_thread_is_registered ();
 329 #else
 330         return TRUE;
 331 #endif
 332 }
 333
 334 extern int GC_thread_register_foreign (void *base_addr);
 335
 336 gboolean
 337 mono_gc_register_thread (void *baseptr)
 338 {
 339         return mono_thread_info_attach (baseptr) != NULL;
 340 }
 341
 342 static void*
 343 boehm_thread_register (MonoThreadInfo* info, void *baseptr)
 344 {
 345 #if GC_VERSION_MAJOR >= 7
 346         struct GC_stack_base sb;
 347         int res;
 348
 349         res = GC_get_stack_base (&sb);
 350         if (res != GC_SUCCESS) {
 351                 sb.mem_base = baseptr;
 352 #ifdef __ia64__
 353                 /* Can't determine the register stack bounds */
 354                 g_error ("mono_gc_register_thread failed ().\n");
 355 #endif
 356         }
 357         res = GC_register_my_thread (&sb);
 358         if ((res != GC_SUCCESS) && (res != GC_DUPLICATE)) {
 359                 g_warning ("GC_register_my_thread () failed.\n");
 360                 return NULL;
 361         }
 362         return info;
 363 #else
 364         if (mono_gc_is_gc_thread())
 365                 return info;
 366 #if defined(USE_INCLUDED_LIBGC) && !defined(HOST_WIN32)
 367         return GC_thread_register_foreign (baseptr) ? info : NULL;
 368 #else
 369         return NULL;
 370 #endif
 371 #endif
 372 }
 373
 374 gboolean
 375 mono_object_is_alive (MonoObject* o)
 376 {
 377 #ifdef USE_INCLUDED_LIBGC
 378         return GC_is_marked ((gpointer)o);
 379 #else
 380         return TRUE;
 381 #endif
 382 }
 383
 384 int
 385 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
 386 {
 387         return 1;
 388 }
 389
 390 #ifdef USE_INCLUDED_LIBGC
 391
 392 static gint64 gc_start_time;
 393
 394 static void
 395 on_gc_notification (GCEventType event)
 396 {
 397         MonoGCEvent e = (MonoGCEvent)event;
 398
 399         switch (e) {
 400         case MONO_GC_EVENT_PRE_STOP_WORLD:
 401                 MONO_GC_WORLD_STOP_BEGIN ();
 402                 mono_thread_info_suspend_lock ();
 403                 break;
 404
 405         case MONO_GC_EVENT_POST_STOP_WORLD:
 406                 MONO_GC_WORLD_STOP_END ();
 407                 break;
 408
 409         case MONO_GC_EVENT_PRE_START_WORLD:
 410                 MONO_GC_WORLD_RESTART_BEGIN (1);
 411                 break;
 412
 413         case MONO_GC_EVENT_POST_START_WORLD:
 414                 MONO_GC_WORLD_RESTART_END (1);
 415                 mono_thread_info_suspend_unlock ();
 416                 break;
 417
 418         case MONO_GC_EVENT_START:
 419                 MONO_GC_BEGIN (1);
 420 #ifndef DISABLE_PERFCOUNTERS
 421                 if (mono_perfcounters)
 422                         mono_perfcounters->gc_collections0++;
 423 #endif
 424                 gc_stats.major_gc_count ++;
 425                 gc_start_time = mono_100ns_ticks ();
 426                 break;
 427
 428         case MONO_GC_EVENT_END:
 429                 MONO_GC_END (1);
 430 #if defined(ENABLE_DTRACE) && defined(__sun__)
 431                 /* This works around a dtrace -G problem on Solaris.
 432                    Limit its actual use to when the probe is enabled. */
 433                 if (MONO_GC_END_ENABLED ())
 434                         sleep(0);
 435 #endif
 436
 437 #ifndef DISABLE_PERFCOUNTERS
 438                 if (mono_perfcounters) {
 439                         guint64 heap_size = GC_get_heap_size ();
 440                         guint64 used_size = heap_size - GC_get_free_bytes ();
 441                         mono_perfcounters->gc_total_bytes = used_size;
 442                         mono_perfcounters->gc_committed_bytes = heap_size;
 443                         mono_perfcounters->gc_reserved_bytes = heap_size;
 444                         mono_perfcounters->gc_gen0size = heap_size;
 445                 }
 446 #endif
 447                 gc_stats.major_gc_time_usecs += (mono_100ns_ticks () - gc_start_time) / 10;
 448                 mono_trace_message (MONO_TRACE_GC, "gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
 449                 break;
 450         }
 451
 452         mono_profiler_gc_event (e, 0);
 453 }
 454
 455 static void
 456 on_gc_heap_resize (size_t new_size)
 457 {
 458         guint64 heap_size = GC_get_heap_size ();
 459 #ifndef DISABLE_PERFCOUNTERS
 460         if (mono_perfcounters) {
 461                 mono_perfcounters->gc_committed_bytes = heap_size;
 462                 mono_perfcounters->gc_reserved_bytes = heap_size;
 463                 mono_perfcounters->gc_gen0size = heap_size;
 464         }
 465 #endif
 466         mono_profiler_gc_heap_resize (new_size);
 467 }
 468
 469 void
 470 mono_gc_enable_events (void)
 471 {
 472         GC_notify_event = on_gc_notification;
 473         GC_on_heap_resize = on_gc_heap_resize;
 474 }
 475
 476 #else
 477
 478 void
 479 mono_gc_enable_events (void)
 480 {
 481 }
 482
 483 #endif
 484
 485 int
 486 mono_gc_register_root (char *start, size_t size, void *descr)
 487 {
 488         /* for some strange reason, they want one extra byte on the end */
 489         GC_add_roots (start, start + size + 1);
 490
 491         return TRUE;
 492 }
 493
 494 void
 495 mono_gc_deregister_root (char* addr)
 496 {
 497 #ifndef HOST_WIN32
 498         /* FIXME: libgc doesn't define this work win32 for some reason */
 499         /* FIXME: No size info */
 500         GC_remove_roots (addr, addr + sizeof (gpointer) + 1);
 501 #endif
 502 }
 503
 504 void
 505 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
 506 {
 507         /* libgc requires that we use HIDE_POINTER... */
 508         *link_addr = (void*)HIDE_POINTER (obj);
 509         if (track)
 510                 GC_REGISTER_LONG_LINK (link_addr, obj);
 511         else
 512                 GC_GENERAL_REGISTER_DISAPPEARING_LINK (link_addr, obj);
 513 }
 514
 515 void
 516 mono_gc_weak_link_remove (void **link_addr, gboolean track)
 517 {
 518         if (track)
 519                 GC_unregister_long_link (link_addr);
 520         else
 521                 GC_unregister_disappearing_link (link_addr);
 522         *link_addr = NULL;
 523 }
 524
 525 static gpointer
 526 reveal_link (gpointer link_addr)
 527 {
 528         void **link_a = link_addr;
 529         return REVEAL_POINTER (*link_a);
 530 }
 531
 532 MonoObject*
 533 mono_gc_weak_link_get (void **link_addr)
 534 {
 535         MonoObject *obj = GC_call_with_alloc_lock (reveal_link, link_addr);
 536         if (obj == (MonoObject *) -1)
 537                 return NULL;
 538         return obj;
 539 }
 540
 541 void*
 542 mono_gc_make_descr_for_string (gsize *bitmap, int numbits)
 543 {
 544         return mono_gc_make_descr_from_bitmap (bitmap, numbits);
 545 }
 546
 547 void*
 548 mono_gc_make_descr_for_object (gsize *bitmap, int numbits, size_t obj_size)
 549 {
 550         return mono_gc_make_descr_from_bitmap (bitmap, numbits);
 551 }
 552
 553 void*
 554 mono_gc_make_descr_for_array (int vector, gsize *elem_bitmap, int numbits, size_t elem_size)
 555 {
 556         /* libgc has no usable support for arrays... */
 557         return GC_NO_DESCRIPTOR;
 558 }
 559
 560 void*
 561 mono_gc_make_descr_from_bitmap (gsize *bitmap, int numbits)
 562 {
 563 #ifdef HAVE_GC_GCJ_MALLOC
 564         /* It seems there are issues when the bitmap doesn't fit: play it safe */
 565         if (numbits >= 30)
 566                 return GC_NO_DESCRIPTOR;
 567         else
 568                 return (gpointer)GC_make_descriptor ((GC_bitmap)bitmap, numbits);
 569 #else
 570         return NULL;
 571 #endif
 572 }
 573
 574 void*
 575 mono_gc_make_root_descr_all_refs (int numbits)
 576 {
 577         return NULL;
 578 }
 579
 580 void*
 581 mono_gc_alloc_fixed (size_t size, void *descr)
 582 {
 583         /* To help track down typed allocation bugs */
 584         /*
 585         static int count;
 586         count ++;
 587         if (count == atoi (getenv ("COUNT2")))
 588                 printf ("HIT!\n");
 589         if (count > atoi (getenv ("COUNT2")))
 590                 return GC_MALLOC (size);
 591         */
 592
 593         if (descr)
 594                 return GC_MALLOC_EXPLICITLY_TYPED (size, (GC_descr)descr);
 595         else
 596                 return GC_MALLOC (size);
 597 }
 598
 599 void
 600 mono_gc_free_fixed (void* addr)
 601 {
 602 }
 603
 604 int
 605 mono_gc_invoke_finalizers (void)
 606 {
 607         /* There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
 608          * the 'mem_freed' variable is not initialized when there are no
 609          * objects to finalize, which leads to strange behavior later on.
 610          * The check is necessary to work around that bug.
 611          */
 612         if (GC_should_invoke_finalizers ())
 613                 return GC_invoke_finalizers ();
 614         return 0;
 615 }
 616
 617 gboolean
 618 mono_gc_pending_finalizers (void)
 619 {
 620         return GC_should_invoke_finalizers ();
 621 }
 622
 623 void
 624 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
 625 {
 626         *(void**)field_ptr = value;
 627 }
 628
 629 void
 630 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
 631 {
 632         *(void**)slot_ptr = value;
 633 }
 634
 635 void
 636 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
 637 {
 638         mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
 639 }
 640
 641 void
 642 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
 643 {
 644         *(void**)ptr = value;
 645 }
 646
 647 void
 648 mono_gc_wbarrier_generic_nostore (gpointer ptr)
 649 {
 650 }
 651
 652 void
 653 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
 654 {
 655         mono_gc_memmove (dest, src, count * mono_class_value_size (klass, NULL));
 656 }
 657
 658 void
 659 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
 660 {
 661         /* do not copy the sync state */
 662         mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
 663                         mono_object_class (obj)->instance_size - sizeof (MonoObject));
 664 }
 665
 666 void
 667 mono_gc_clear_domain (MonoDomain *domain)
 668 {
 669 }
 670
 671 int
 672 mono_gc_get_suspend_signal (void)
 673 {
 674 #ifdef USE_INCLUDED_GC
 675         return GC_get_suspend_signal ();
 676 #else
 677         return -1;
 678 #endif
 679 }
 680
 681 #if defined(USE_INCLUDED_LIBGC) && defined(USE_COMPILER_TLS) && defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
 682 extern __thread MONO_TLS_FAST void* GC_thread_tls;
 683 #include "metadata-internals.h"
 684
 685 static int
 686 shift_amount (int v)
 687 {
 688         int i = 0;
 689         while (!(v & (1 << i)))
 690                 i++;
 691         return i;
 692 }
 693
 694 enum {
 695         ATYPE_FREEPTR,
 696         ATYPE_FREEPTR_FOR_BOX,
 697         ATYPE_NORMAL,
 698         ATYPE_GCJ,
 699         ATYPE_STRING,
 700         ATYPE_NUM
 701 };
 702
 703 static MonoMethod*
 704 create_allocator (int atype, int offset)
 705 {
 706         int index_var, bytes_var, my_fl_var, my_entry_var;
 707         guint32 no_freelist_branch, not_small_enough_branch = 0;
 708         guint32 size_overflow_branch = 0;
 709         MonoMethodBuilder *mb;
 710         MonoMethod *res;
 711         MonoMethodSignature *csig;
 712         AllocatorWrapperInfo *info;
 713
 714         if (atype == ATYPE_STRING) {
 715                 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 2);
 716                 csig->ret = &mono_defaults.string_class->byval_arg;
 717                 csig->params [0] = &mono_defaults.int_class->byval_arg;
 718                 csig->params [1] = &mono_defaults.int32_class->byval_arg;
 719         } else {
 720                 csig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
 721                 csig->ret = &mono_defaults.object_class->byval_arg;
 722                 csig->params [0] = &mono_defaults.int_class->byval_arg;
 723         }
 724
 725         mb = mono_mb_new (mono_defaults.object_class, "Alloc", MONO_WRAPPER_ALLOC);
 726         bytes_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
 727         if (atype == ATYPE_STRING) {
 728                 /* a string alloator method takes the args: (vtable, len) */
 729                 /* bytes = (sizeof (MonoString) + ((len + 1) * 2)); */
 730                 mono_mb_emit_ldarg (mb, 1);
 731                 mono_mb_emit_icon (mb, 1);
 732                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 733                 mono_mb_emit_icon (mb, 1);
 734                 mono_mb_emit_byte (mb, MONO_CEE_SHL);
 735                 // sizeof (MonoString) might include padding
 736                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, chars));
 737                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 738                 mono_mb_emit_stloc (mb, bytes_var);
 739         } else {
 740                 /* bytes = vtable->klass->instance_size */
 741                 mono_mb_emit_ldarg (mb, 0);
 742                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoVTable, klass));
 743                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 744                 mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 745                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoClass, instance_size));
 746                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 747                 /* FIXME: assert instance_size stays a 4 byte integer */
 748                 mono_mb_emit_byte (mb, MONO_CEE_LDIND_U4);
 749                 mono_mb_emit_stloc (mb, bytes_var);
 750         }
 751
 752         /* this is needed for strings/arrays only as the other big types are never allocated with this method */
 753         if (atype == ATYPE_STRING) {
 754                 /* check for size */
 755                 /* if (!SMALL_ENOUGH (bytes)) jump slow_path;*/
 756                 mono_mb_emit_ldloc (mb, bytes_var);
 757                 mono_mb_emit_icon (mb, (NFREELISTS-1) * GRANULARITY);
 758                 not_small_enough_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BGT_UN_S);
 759                 /* check for overflow */
 760                 mono_mb_emit_ldloc (mb, bytes_var);
 761                 mono_mb_emit_icon (mb, sizeof (MonoString));
 762                 size_overflow_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLE_UN_S);
 763         }
 764
 765         /* int index = INDEX_FROM_BYTES(bytes); */
 766         index_var = mono_mb_add_local (mb, &mono_defaults.int32_class->byval_arg);
 767
 768         mono_mb_emit_ldloc (mb, bytes_var);
 769         mono_mb_emit_icon (mb, GRANULARITY - 1);
 770         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 771         mono_mb_emit_icon (mb, shift_amount (GRANULARITY));
 772         mono_mb_emit_byte (mb, MONO_CEE_SHR_UN);
 773         mono_mb_emit_icon (mb, shift_amount (sizeof (gpointer)));
 774         mono_mb_emit_byte (mb, MONO_CEE_SHL);
 775         /* index var is already adjusted into bytes */
 776         mono_mb_emit_stloc (mb, index_var);
 777
 778         my_fl_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 779         my_entry_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 780         /* my_fl = ((GC_thread)tsd) -> ptrfree_freelists + index; */
 781         mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
 782         mono_mb_emit_byte (mb, 0x0D); /* CEE_MONO_TLS */
 783         mono_mb_emit_i4 (mb, offset);
 784         if (atype == ATYPE_FREEPTR || atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING)
 785                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, ptrfree_freelists));
 786         else if (atype == ATYPE_NORMAL)
 787                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, normal_freelists));
 788         else if (atype == ATYPE_GCJ)
 789                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (struct GC_Thread_Rep, gcj_freelists));
 790         else
 791                 g_assert_not_reached ();
 792         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 793         mono_mb_emit_ldloc (mb, index_var);
 794         mono_mb_emit_byte (mb, MONO_CEE_ADD);
 795         mono_mb_emit_stloc (mb, my_fl_var);
 796
 797         /* my_entry = *my_fl; */
 798         mono_mb_emit_ldloc (mb, my_fl_var);
 799         mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 800         mono_mb_emit_stloc (mb, my_entry_var);
 801
 802         /* if (EXPECT((word)my_entry >= HBLKSIZE, 1)) { */
 803         mono_mb_emit_ldloc (mb, my_entry_var);
 804         mono_mb_emit_icon (mb, HBLKSIZE);
 805         no_freelist_branch = mono_mb_emit_short_branch (mb, MONO_CEE_BLT_UN_S);
 806
 807         /* ptr_t next = obj_link(my_entry); *my_fl = next; */
 808         mono_mb_emit_ldloc (mb, my_fl_var);
 809         mono_mb_emit_ldloc (mb, my_entry_var);
 810         mono_mb_emit_byte (mb, MONO_CEE_LDIND_I);
 811         mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 812
 813         /* set the vtable and clear the words in the object */
 814         mono_mb_emit_ldloc (mb, my_entry_var);
 815         mono_mb_emit_ldarg (mb, 0);
 816         mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 817
 818         if (atype == ATYPE_FREEPTR) {
 819                 int start_var, end_var, start_loop;
 820                 /* end = my_entry + bytes; start = my_entry + sizeof (gpointer);
 821                  */
 822                 start_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 823                 end_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
 824                 mono_mb_emit_ldloc (mb, my_entry_var);
 825                 mono_mb_emit_ldloc (mb, bytes_var);
 826                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 827                 mono_mb_emit_stloc (mb, end_var);
 828                 mono_mb_emit_ldloc (mb, my_entry_var);
 829                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
 830                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 831                 mono_mb_emit_stloc (mb, start_var);
 832                 /*
 833                  * do {
 834                  *      *start++ = NULL;
 835                  * } while (start < end);
 836                  */
 837                 start_loop = mono_mb_get_label (mb);
 838                 mono_mb_emit_ldloc (mb, start_var);
 839                 mono_mb_emit_icon (mb, 0);
 840                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 841                 mono_mb_emit_ldloc (mb, start_var);
 842                 mono_mb_emit_icon (mb, sizeof (gpointer));
 843                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 844                 mono_mb_emit_stloc (mb, start_var);
 845
 846                 mono_mb_emit_ldloc (mb, start_var);
 847                 mono_mb_emit_ldloc (mb, end_var);
 848                 mono_mb_emit_byte (mb, MONO_CEE_BLT_UN_S);
 849                 mono_mb_emit_byte (mb, start_loop - (mono_mb_get_label (mb) + 1));
 850         } else if (atype == ATYPE_FREEPTR_FOR_BOX || atype == ATYPE_STRING) {
 851                 /* need to clear just the sync pointer */
 852                 mono_mb_emit_ldloc (mb, my_entry_var);
 853                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation));
 854                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 855                 mono_mb_emit_icon (mb, 0);
 856                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I);
 857         }
 858
 859         if (atype == ATYPE_STRING) {
 860                 /* need to set length and clear the last char */
 861                 /* s->length = len; */
 862                 mono_mb_emit_ldloc (mb, my_entry_var);
 863                 mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoString, length));
 864                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 865                 mono_mb_emit_ldarg (mb, 1);
 866                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I4);
 867                 /* s->chars [len] = 0; */
 868                 mono_mb_emit_ldloc (mb, my_entry_var);
 869                 mono_mb_emit_ldloc (mb, bytes_var);
 870                 mono_mb_emit_icon (mb, 2);
 871                 mono_mb_emit_byte (mb, MONO_CEE_SUB);
 872                 mono_mb_emit_byte (mb, MONO_CEE_ADD);
 873                 mono_mb_emit_icon (mb, 0);
 874                 mono_mb_emit_byte (mb, MONO_CEE_STIND_I2);
 875         }
 876
 877         /* return my_entry; */
 878         mono_mb_emit_ldloc (mb, my_entry_var);
 879         mono_mb_emit_byte (mb, MONO_CEE_RET);
 880
 881         mono_mb_patch_short_branch (mb, no_freelist_branch);
 882         if (not_small_enough_branch > 0)
 883                 mono_mb_patch_short_branch (mb, not_small_enough_branch);
 884         if (size_overflow_branch > 0)
 885                 mono_mb_patch_short_branch (mb, size_overflow_branch);
 886         /* the slow path: we just call back into the runtime */
 887         if (atype == ATYPE_STRING) {
 888                 mono_mb_emit_ldarg (mb, 1);
 889                 mono_mb_emit_icall (mb, mono_string_alloc);
 890         } else {
 891                 mono_mb_emit_ldarg (mb, 0);
 892                 mono_mb_emit_icall (mb, mono_object_new_specific);
 893         }
 894
 895         mono_mb_emit_byte (mb, MONO_CEE_RET);
 896
 897         res = mono_mb_create_method (mb, csig, 8);
 898         mono_mb_free (mb);
 899         mono_method_get_header (res)->init_locals = FALSE;
 900
 901         info = mono_image_alloc0 (mono_defaults.corlib, sizeof (AllocatorWrapperInfo));
 902         info->gc_name = "boehm";
 903         info->alloc_type = atype;
 904         mono_marshal_set_wrapper_info (res, info);
 905
 906         return res;
 907 }
 908
 909 static MonoMethod* alloc_method_cache [ATYPE_NUM];
 910
 911 static G_GNUC_UNUSED gboolean
 912 mono_gc_is_critical_method (MonoMethod *method)
 913 {
 914         int i;
 915
 916         for (i = 0; i < ATYPE_NUM; ++i)
 917                 if (method == alloc_method_cache [i])
 918                         return TRUE;
 919
 920         return FALSE;
 921 }
 922
 923 /*
 924  * If possible, generate a managed method that can quickly allocate objects in class
 925  * @klass. The method will typically have an thread-local inline allocation sequence.
 926  * The signature of the called method is:
 927  *      object allocate (MonoVTable *vtable)
 928  * Some of the logic here is similar to mono_class_get_allocation_ftn () i object.c,
 929  * keep in sync.
 930  * The thread local alloc logic is taken from libgc/pthread_support.c.
 931  */
 932
 933 MonoMethod*
 934 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
 935 {
 936         int offset = -1;
 937         int atype;
 938         MonoClass *klass = vtable->klass;
 939         MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
 940
 941         /*g_print ("thread tls: %d\n", offset);*/
 942         if (offset == -1)
 943                 return NULL;
 944         if (!SMALL_ENOUGH (klass->instance_size))
 945                 return NULL;
 946         if (mono_class_has_finalizer (klass) || klass->marshalbyref || (mono_profiler_get_events () & MONO_PROFILE_ALLOCATIONS))
 947                 return NULL;
 948         if (klass->rank)
 949                 return NULL;
 950         if (klass->byval_arg.type == MONO_TYPE_STRING) {
 951                 atype = ATYPE_STRING;
 952         } else if (!klass->has_references) {
 953                 if (for_box)
 954                         atype = ATYPE_FREEPTR_FOR_BOX;
 955                 else
 956                         atype = ATYPE_FREEPTR;
 957         } else {
 958                 return NULL;
 959                 /*
 960                  * disabled because we currently do a runtime choice anyway, to
 961                  * deal with multiple appdomains.
 962                 if (vtable->gc_descr != GC_NO_DESCRIPTOR)
 963                         atype = ATYPE_GCJ;
 964                 else
 965                         atype = ATYPE_NORMAL;
 966                 */
 967         }
 968         return mono_gc_get_managed_allocator_by_type (atype);
 969 }
 970
 971 MonoMethod*
 972 mono_gc_get_managed_array_allocator (MonoVTable *vtable, int rank)
 973 {
 974         return NULL;
 975 }
 976
 977 /**
 978  * mono_gc_get_managed_allocator_by_type:
 979  *
 980  *   Return a managed allocator method corresponding to allocator type ATYPE.
 981  */
 982 MonoMethod*
 983 mono_gc_get_managed_allocator_by_type (int atype)
 984 {
 985         int offset = -1;
 986         MonoMethod *res;
 987         MONO_THREAD_VAR_OFFSET (GC_thread_tls, offset);
 988
 989         mono_loader_lock ();
 990         res = alloc_method_cache [atype];
 991         if (!res)
 992                 res = alloc_method_cache [atype] = create_allocator (atype, offset);
 993         mono_loader_unlock ();
 994         return res;
 995 }
 996
 997 guint32
 998 mono_gc_get_managed_allocator_types (void)
 999 {
1000         return ATYPE_NUM;
1001 }
1002
1003 MonoMethod*
1004 mono_gc_get_write_barrier (void)
1005 {
1006         g_assert_not_reached ();
1007         return NULL;
1008 }
1009
1010 #else
1011
1012 static G_GNUC_UNUSED gboolean
1013 mono_gc_is_critical_method (MonoMethod *method)
1014 {
1015         return FALSE;
1016 }
1017
1018 MonoMethod*
1019 mono_gc_get_managed_allocator (MonoVTable *vtable, gboolean for_box)
1020 {
1021         return NULL;
1022 }
1023
1024 MonoMethod*
1025 mono_gc_get_managed_array_allocator (MonoVTable *vtable, int rank)
1026 {
1027         return NULL;
1028 }
1029
1030 MonoMethod*
1031 mono_gc_get_managed_allocator_by_type (int atype)
1032 {
1033         return NULL;
1034 }
1035
1036 guint32
1037 mono_gc_get_managed_allocator_types (void)
1038 {
1039         return 0;
1040 }
1041
1042 MonoMethod*
1043 mono_gc_get_write_barrier (void)
1044 {
1045         g_assert_not_reached ();
1046         return NULL;
1047 }
1048
1049 #endif
1050
1051 const char *
1052 mono_gc_get_gc_name (void)
1053 {
1054         return "boehm";
1055 }
1056
1057 void*
1058 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
1059 {
1060         return GC_call_with_alloc_lock (func, data);
1061 }
1062
1063 char*
1064 mono_gc_get_description (void)
1065 {
1066         return g_strdup (DEFAULT_GC_NAME);
1067 }
1068
1069 void
1070 mono_gc_set_desktop_mode (void)
1071 {
1072         GC_dont_expand = 1;
1073 }
1074
1075 gboolean
1076 mono_gc_is_moving (void)
1077 {
1078         return FALSE;
1079 }
1080
1081 gboolean
1082 mono_gc_is_disabled (void)
1083 {
1084         if (GC_dont_gc || g_getenv ("GC_DONT_GC"))
1085                 return TRUE;
1086         else
1087                 return FALSE;
1088 }
1089
1090 void
1091 mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
1092 {
1093         g_assert_not_reached ();
1094 }
1095
1096
1097 guint8*
1098 mono_gc_get_card_table (int *shift_bits, gpointer *card_mask)
1099 {
1100         g_assert_not_reached ();
1101         return NULL;
1102 }
1103
1104 gboolean
1105 mono_gc_card_table_nursery_check (void)
1106 {
1107         g_assert_not_reached ();
1108         return TRUE;
1109 }
1110
1111 void*
1112 mono_gc_get_nursery (int *shift_bits, size_t *size)
1113 {
1114         return NULL;
1115 }
1116
1117 void
1118 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1119 {
1120 }
1121
1122 gboolean
1123 mono_gc_precise_stack_mark_enabled (void)
1124 {
1125         return FALSE;
1126 }
1127
1128 FILE *
1129 mono_gc_get_logfile (void)
1130 {
1131         return NULL;
1132 }
1133
1134 void
1135 mono_gc_conservatively_scan_area (void *start, void *end)
1136 {
1137         g_assert_not_reached ();
1138 }
1139
1140 void *
1141 mono_gc_scan_object (void *obj)
1142 {
1143         g_assert_not_reached ();
1144         return NULL;
1145 }
1146
1147 gsize*
1148 mono_gc_get_bitmap_for_descr (void *descr, int *numbits)
1149 {
1150         g_assert_not_reached ();
1151         return NULL;
1152 }
1153
1154 void
1155 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
1156 {
1157 }
1158
1159 void
1160 mono_gc_set_stack_end (void *stack_end)
1161 {
1162 }
1163
1164 void mono_gc_set_skip_thread (gboolean value)
1165 {
1166 }
1167
1168 /*
1169  * These will call the redefined versions in libgc.
1170  */
1171
1172 #ifndef HOST_WIN32
1173
1174 int
1175 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
1176 {
1177         return pthread_create (new_thread, attr, start_routine, arg);
1178 }
1179
1180 int
1181 mono_gc_pthread_join (pthread_t thread, void **retval)
1182 {
1183         return pthread_join (thread, retval);
1184 }
1185
1186 int
1187 mono_gc_pthread_detach (pthread_t thread)
1188 {
1189         return pthread_detach (thread);
1190 }
1191
1192 void
1193 mono_gc_pthread_exit (void *retval)
1194 {
1195         pthread_exit (retval);
1196 }
1197
1198 #endif
1199
1200 #ifdef HOST_WIN32
1201 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
1202 {
1203 #ifdef USE_INCLUDED_LIBGC
1204         return GC_DllMain (module_handle, reason, reserved);
1205 #else
1206         return TRUE;
1207 #endif
1208 }
1209 #endif
1210
1211 guint
1212 mono_gc_get_vtable_bits (MonoClass *class)
1213 {
1214         return 0;
1215 }
1216
1217 /*
1218  * mono_gc_register_altstack:
1219  *
1220  *   Register the dimensions of the normal stack and altstack with the collector.
1221  * Currently, STACK/STACK_SIZE is only used when the thread is suspended while it is on an altstack.
1222  */
1223 void
1224 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
1225 {
1226 #ifdef USE_INCLUDED_LIBGC
1227         GC_register_altstack (stack, stack_size, altstack, altstack_size);
1228 #endif
1229 }
1230
1231 int
1232 mono_gc_get_los_limit (void)
1233 {
1234         return G_MAXINT;
1235 }
1236
1237 gboolean
1238 mono_gc_user_markers_supported (void)
1239 {
1240         return FALSE;
1241 }
1242
1243 void *
1244 mono_gc_make_root_descr_user (MonoGCRootMarkFunc marker)
1245 {
1246         g_assert_not_reached ();
1247         return NULL;
1248 }
1249
1250 #endif /* no Boehm GC */