mono/metadata/sgen-gc.c

   1 /*
   2  * sgen-gc.c: Simple generational GC.
   3  *
   4  * Author:
   5  *      Paolo Molaro (lupus@ximian.com)
   6  *  Rodrigo Kumpera (kumpera@gmail.com)
   7  *
   8  * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
   9  * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
  10  *
  11  * Thread start/stop adapted from Boehm's GC:
  12  * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
  13  * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
  14  * Copyright (c) 1998 by Fergus Henderson.  All rights reserved.
  15  * Copyright (c) 2000-2004 by Hewlett-Packard Company.  All rights reserved.
  16  * Copyright 2001-2003 Ximian, Inc
  17  * Copyright 2003-2010 Novell, Inc.
  18  * Copyright 2011 Xamarin, Inc.
  19  * Copyright (C) 2012 Xamarin Inc
  20  *
  21  * This library is free software; you can redistribute it and/or
  22  * modify it under the terms of the GNU Library General Public
  23  * License 2.0 as published by the Free Software Foundation;
  24  *
  25  * This library is distributed in the hope that it will be useful,
  26  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  28  * Library General Public License for more details.
  29  *
  30  * You should have received a copy of the GNU Library General Public
  31  * License 2.0 along with this library; if not, write to the Free
  32  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  33  *
  34  * Important: allocation provides always zeroed memory, having to do
  35  * a memset after allocation is deadly for performance.
  36  * Memory usage at startup is currently as follows:
  37  * 64 KB pinned space
  38  * 64 KB internal space
  39  * size of nursery
  40  * We should provide a small memory config with half the sizes
  41  *
  42  * We currently try to make as few mono assumptions as possible:
  43  * 1) 2-word header with no GC pointers in it (first vtable, second to store the
  44  *    forwarding ptr)
  45  * 2) gc descriptor is the second word in the vtable (first word in the class)
  46  * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
  47  * 4) there is a function to get an object's size and the number of
  48  *    elements in an array.
  49  * 5) we know the special way bounds are allocated for complex arrays
  50  * 6) we know about proxies and how to treat them when domains are unloaded
  51  *
  52  * Always try to keep stack usage to a minimum: no recursive behaviour
  53  * and no large stack allocs.
  54  *
  55  * General description.
  56  * Objects are initially allocated in a nursery using a fast bump-pointer technique.
  57  * When the nursery is full we start a nursery collection: this is performed with a
  58  * copying GC.
  59  * When the old generation is full we start a copying GC of the old generation as well:
  60  * this will be changed to mark&sweep with copying when fragmentation becomes to severe
  61  * in the future.  Maybe we'll even do both during the same collection like IMMIX.
  62  *
  63  * The things that complicate this description are:
  64  * *) pinned objects: we can't move them so we need to keep track of them
  65  * *) no precise info of the thread stacks and registers: we need to be able to
  66  *    quickly find the objects that may be referenced conservatively and pin them
  67  *    (this makes the first issues more important)
  68  * *) large objects are too expensive to be dealt with using copying GC: we handle them
  69  *    with mark/sweep during major collections
  70  * *) some objects need to not move even if they are small (interned strings, Type handles):
  71  *    we use mark/sweep for them, too: they are not allocated in the nursery, but inside
  72  *    PinnedChunks regions
  73  */
  74
  75 /*
  76  * TODO:
  77
  78  *) we could have a function pointer in MonoClass to implement
  79   customized write barriers for value types
  80
  81  *) investigate the stuff needed to advance a thread to a GC-safe
  82   point (single-stepping, read from unmapped memory etc) and implement it.
  83   This would enable us to inline allocations and write barriers, for example,
  84   or at least parts of them, like the write barrier checks.
  85   We may need this also for handling precise info on stacks, even simple things
  86   as having uninitialized data on the stack and having to wait for the prolog
  87   to zero it. Not an issue for the last frame that we scan conservatively.
  88   We could always not trust the value in the slots anyway.
  89
  90  *) modify the jit to save info about references in stack locations:
  91   this can be done just for locals as a start, so that at least
  92   part of the stack is handled precisely.
  93
  94  *) test/fix endianess issues
  95
  96  *) Implement a card table as the write barrier instead of remembered
  97     sets?  Card tables are not easy to implement with our current
  98     memory layout.  We have several different kinds of major heap
  99     objects: Small objects in regular blocks, small objects in pinned
 100     chunks and LOS objects.  If we just have a pointer we have no way
 101     to tell which kind of object it points into, therefore we cannot
 102     know where its card table is.  The least we have to do to make
 103     this happen is to get rid of write barriers for indirect stores.
 104     (See next item)
 105
 106  *) Get rid of write barriers for indirect stores.  We can do this by
 107     telling the GC to wbarrier-register an object once we do an ldloca
 108     or ldelema on it, and to unregister it once it's not used anymore
 109     (it can only travel downwards on the stack).  The problem with
 110     unregistering is that it needs to happen eventually no matter
 111     what, even if exceptions are thrown, the thread aborts, etc.
 112     Rodrigo suggested that we could do only the registering part and
 113     let the collector find out (pessimistically) when it's safe to
 114     unregister, namely when the stack pointer of the thread that
 115     registered the object is higher than it was when the registering
 116     happened.  This might make for a good first implementation to get
 117     some data on performance.
 118
 119  *) Some sort of blacklist support?  Blacklists is a concept from the
 120     Boehm GC: if during a conservative scan we find pointers to an
 121     area which we might use as heap, we mark that area as unusable, so
 122     pointer retention by random pinning pointers is reduced.
 123
 124  *) experiment with max small object size (very small right now - 2kb,
 125     because it's tied to the max freelist size)
 126
 127   *) add an option to mmap the whole heap in one chunk: it makes for many
 128      simplifications in the checks (put the nursery at the top and just use a single
 129      check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
 130      not flexible (too much of the address space may be used by default or we can't
 131      increase the heap as needed) and we'd need a race-free mechanism to return memory
 132      back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
 133      was written to, munmap is needed, but the following mmap may not find the same segment
 134      free...)
 135
 136  *) memzero the major fragments after restarting the world and optionally a smaller
 137     chunk at a time
 138
 139  *) investigate having fragment zeroing threads
 140
 141  *) separate locks for finalization and other minor stuff to reduce
 142     lock contention
 143
 144  *) try a different copying order to improve memory locality
 145
 146  *) a thread abort after a store but before the write barrier will
 147     prevent the write barrier from executing
 148
 149  *) specialized dynamically generated markers/copiers
 150
 151  *) Dynamically adjust TLAB size to the number of threads.  If we have
 152     too many threads that do allocation, we might need smaller TLABs,
 153     and we might get better performance with larger TLABs if we only
 154     have a handful of threads.  We could sum up the space left in all
 155     assigned TLABs and if that's more than some percentage of the
 156     nursery size, reduce the TLAB size.
 157
 158  *) Explore placing unreachable objects on unused nursery memory.
 159         Instead of memset'ng a region to zero, place an int[] covering it.
 160         A good place to start is add_nursery_frag. The tricky thing here is
 161         placing those objects atomically outside of a collection.
 162
 163  *) Allocation should use asymmetric Dekker synchronization:
 164         http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
 165         This should help weak consistency archs.
 166  */
 167 #include "config.h"
 168 #ifdef HAVE_SGEN_GC
 169
 170 #ifdef __MACH__
 171 #undef _XOPEN_SOURCE
 172 #define _XOPEN_SOURCE
 173 #define _DARWIN_C_SOURCE
 174 #endif
 175
 176 #ifdef HAVE_UNISTD_H
 177 #include <unistd.h>
 178 #endif
 179 #ifdef HAVE_PTHREAD_H
 180 #include <pthread.h>
 181 #endif
 182 #ifdef HAVE_PTHREAD_NP_H
 183 #include <pthread_np.h>
 184 #endif
 185 #ifdef HAVE_SEMAPHORE_H
 186 #include <semaphore.h>
 187 #endif
 188 #include <stdio.h>
 189 #include <string.h>
 190 #include <signal.h>
 191 #include <errno.h>
 192 #include <assert.h>
 193
 194 #include "metadata/sgen-gc.h"
 195 #include "metadata/metadata-internals.h"
 196 #include "metadata/class-internals.h"
 197 #include "metadata/gc-internal.h"
 198 #include "metadata/object-internals.h"
 199 #include "metadata/threads.h"
 200 #include "metadata/sgen-cardtable.h"
 201 #include "metadata/sgen-protocol.h"
 202 #include "metadata/sgen-archdep.h"
 203 #include "metadata/sgen-bridge.h"
 204 #include "metadata/sgen-memory-governor.h"
 205 #include "metadata/sgen-hash-table.h"
 206 #include "metadata/mono-gc.h"
 207 #include "metadata/method-builder.h"
 208 #include "metadata/profiler-private.h"
 209 #include "metadata/monitor.h"
 210 #include "metadata/threadpool-internals.h"
 211 #include "metadata/mempool-internals.h"
 212 #include "metadata/marshal.h"
 213 #include "metadata/runtime.h"
 214 #include "metadata/sgen-cardtable.h"
 215 #include "metadata/sgen-pinning.h"
 216 #include "metadata/sgen-workers.h"
 217 #include "utils/mono-mmap.h"
 218 #include "utils/mono-time.h"
 219 #include "utils/mono-semaphore.h"
 220 #include "utils/mono-counters.h"
 221 #include "utils/mono-proclib.h"
 222 #include "utils/mono-memory-model.h"
 223 #include "utils/mono-logger-internal.h"
 224 #include "utils/dtrace.h"
 225
 226 #include <mono/utils/mono-logger-internal.h>
 227 #include <mono/utils/memcheck.h>
 228
 229 #if defined(__MACH__)
 230 #include "utils/mach-support.h"
 231 #endif
 232
 233 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
 234         a = i,
 235
 236 enum {
 237 #include "mono/cil/opcode.def"
 238         CEE_LAST
 239 };
 240
 241 #undef OPDEF
 242
 243 #undef pthread_create
 244 #undef pthread_join
 245 #undef pthread_detach
 246
 247 /*
 248  * ######################################################################
 249  * ########  Types and constants used by the GC.
 250  * ######################################################################
 251  */
 252
 253 /* 0 means not initialized, 1 is initialized, -1 means in progress */
 254 static int gc_initialized = 0;
 255 /* If set, check if we need to do something every X allocations */
 256 gboolean has_per_allocation_action;
 257 /* If set, do a heap check every X allocation */
 258 guint32 verify_before_allocs = 0;
 259 /* If set, do a minor collection before every X allocation */
 260 guint32 collect_before_allocs = 0;
 261 /* If set, do a whole heap check before each collection */
 262 static gboolean whole_heap_check_before_collection = FALSE;
 263 /* If set, do a heap consistency check before each minor collection */
 264 static gboolean consistency_check_at_minor_collection = FALSE;
 265 /* If set, check whether mark bits are consistent after major collections */
 266 static gboolean check_mark_bits_after_major_collection = FALSE;
 267 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
 268 static gboolean check_nursery_objects_pinned = FALSE;
 269 /* If set, do a few checks when the concurrent collector is used */
 270 static gboolean do_concurrent_checks = FALSE;
 271 /* If set, check that there are no references to the domain left at domain unload */
 272 static gboolean xdomain_checks = FALSE;
 273 /* If not null, dump the heap after each collection into this file */
 274 static FILE *heap_dump_file = NULL;
 275 /* If set, mark stacks conservatively, even if precise marking is possible */
 276 static gboolean conservative_stack_mark = FALSE;
 277 /* If set, do a plausibility check on the scan_starts before and after
 278    each collection */
 279 static gboolean do_scan_starts_check = FALSE;
 280 /*
 281  * If the major collector is concurrent and this is FALSE, we will
 282  * never initiate a synchronous major collection, unless requested via
 283  * GC.Collect().
 284  */
 285 static gboolean allow_synchronous_major = TRUE;
 286 static gboolean nursery_collection_is_parallel = FALSE;
 287 static gboolean disable_minor_collections = FALSE;
 288 static gboolean disable_major_collections = FALSE;
 289 gboolean do_pin_stats = FALSE;
 290 static gboolean do_verify_nursery = FALSE;
 291 static gboolean do_dump_nursery_content = FALSE;
 292
 293 #ifdef HEAVY_STATISTICS
 294 long long stat_objects_alloced_degraded = 0;
 295 long long stat_bytes_alloced_degraded = 0;
 296
 297 long long stat_copy_object_called_nursery = 0;
 298 long long stat_objects_copied_nursery = 0;
 299 long long stat_copy_object_called_major = 0;
 300 long long stat_objects_copied_major = 0;
 301
 302 long long stat_scan_object_called_nursery = 0;
 303 long long stat_scan_object_called_major = 0;
 304
 305 long long stat_slots_allocated_in_vain;
 306
 307 long long stat_nursery_copy_object_failed_from_space = 0;
 308 long long stat_nursery_copy_object_failed_forwarded = 0;
 309 long long stat_nursery_copy_object_failed_pinned = 0;
 310 long long stat_nursery_copy_object_failed_to_space = 0;
 311
 312 static int stat_wbarrier_add_to_global_remset = 0;
 313 static int stat_wbarrier_set_field = 0;
 314 static int stat_wbarrier_set_arrayref = 0;
 315 static int stat_wbarrier_arrayref_copy = 0;
 316 static int stat_wbarrier_generic_store = 0;
 317 static int stat_wbarrier_set_root = 0;
 318 static int stat_wbarrier_value_copy = 0;
 319 static int stat_wbarrier_object_copy = 0;
 320 #endif
 321
 322 int stat_minor_gcs = 0;
 323 int stat_major_gcs = 0;
 324
 325 static long long stat_pinned_objects = 0;
 326
 327 static long long time_minor_pre_collection_fragment_clear = 0;
 328 static long long time_minor_pinning = 0;
 329 static long long time_minor_scan_remsets = 0;
 330 static long long time_minor_scan_pinned = 0;
 331 static long long time_minor_scan_registered_roots = 0;
 332 static long long time_minor_scan_thread_data = 0;
 333 static long long time_minor_finish_gray_stack = 0;
 334 static long long time_minor_fragment_creation = 0;
 335
 336 static long long time_major_pre_collection_fragment_clear = 0;
 337 static long long time_major_pinning = 0;
 338 static long long time_major_scan_pinned = 0;
 339 static long long time_major_scan_registered_roots = 0;
 340 static long long time_major_scan_thread_data = 0;
 341 static long long time_major_scan_alloc_pinned = 0;
 342 static long long time_major_scan_finalized = 0;
 343 static long long time_major_scan_big_objects = 0;
 344 static long long time_major_finish_gray_stack = 0;
 345 static long long time_major_free_bigobjs = 0;
 346 static long long time_major_los_sweep = 0;
 347 static long long time_major_sweep = 0;
 348 static long long time_major_fragment_creation = 0;
 349
 350 int gc_debug_level = 0;
 351 FILE* gc_debug_file;
 352
 353 /*
 354 void
 355 mono_gc_flush_info (void)
 356 {
 357         fflush (gc_debug_file);
 358 }
 359 */
 360
 361 #define TV_DECLARE SGEN_TV_DECLARE
 362 #define TV_GETTIME SGEN_TV_GETTIME
 363 #define TV_ELAPSED SGEN_TV_ELAPSED
 364 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
 365
 366 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
 367
 368 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
 369
 370 #define object_is_forwarded     SGEN_OBJECT_IS_FORWARDED
 371 #define object_is_pinned        SGEN_OBJECT_IS_PINNED
 372 #define pin_object              SGEN_PIN_OBJECT
 373 #define unpin_object            SGEN_UNPIN_OBJECT
 374
 375 #define ptr_in_nursery sgen_ptr_in_nursery
 376
 377 #define LOAD_VTABLE     SGEN_LOAD_VTABLE
 378
 379 static const char*
 380 safe_name (void* obj)
 381 {
 382         MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
 383         return vt->klass->name;
 384 }
 385
 386 #define safe_object_get_size    sgen_safe_object_get_size
 387
 388 const char*
 389 sgen_safe_name (void* obj)
 390 {
 391         return safe_name (obj);
 392 }
 393
 394 /*
 395  * ######################################################################
 396  * ########  Global data.
 397  * ######################################################################
 398  */
 399 LOCK_DECLARE (gc_mutex);
 400
 401 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
 402
 403 static mword pagesize = 4096;
 404 int degraded_mode = 0;
 405
 406 static mword bytes_pinned_from_failed_allocation = 0;
 407
 408 GCMemSection *nursery_section = NULL;
 409 static mword lowest_heap_address = ~(mword)0;
 410 static mword highest_heap_address = 0;
 411
 412 LOCK_DECLARE (sgen_interruption_mutex);
 413 static LOCK_DECLARE (pin_queue_mutex);
 414
 415 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
 416 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
 417
 418 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
 419 struct _FinalizeReadyEntry {
 420         FinalizeReadyEntry *next;
 421         void *object;
 422 };
 423
 424 typedef struct _EphemeronLinkNode EphemeronLinkNode;
 425
 426 struct _EphemeronLinkNode {
 427         EphemeronLinkNode *next;
 428         char *array;
 429 };
 430
 431 typedef struct {
 432        void *key;
 433        void *value;
 434 } Ephemeron;
 435
 436 int current_collection_generation = -1;
 437 volatile gboolean concurrent_collection_in_progress = FALSE;
 438
 439 /* objects that are ready to be finalized */
 440 static FinalizeReadyEntry *fin_ready_list = NULL;
 441 static FinalizeReadyEntry *critical_fin_list = NULL;
 442
 443 static EphemeronLinkNode *ephemeron_list;
 444
 445 /* registered roots: the key to the hash is the root start address */
 446 /*
 447  * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
 448  */
 449 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
 450         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 451         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 452         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
 453 };
 454 static mword roots_size = 0; /* amount of memory in the root set */
 455
 456 #define GC_ROOT_NUM 32
 457 typedef struct {
 458         int count;              /* must be the first field */
 459         void *objects [GC_ROOT_NUM];
 460         int root_types [GC_ROOT_NUM];
 461         uintptr_t extra_info [GC_ROOT_NUM];
 462 } GCRootReport;
 463
 464 static void
 465 notify_gc_roots (GCRootReport *report)
 466 {
 467         if (!report->count)
 468                 return;
 469         mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
 470         report->count = 0;
 471 }
 472
 473 static void
 474 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
 475 {
 476         if (report->count == GC_ROOT_NUM)
 477                 notify_gc_roots (report);
 478         report->objects [report->count] = object;
 479         report->root_types [report->count] = rtype;
 480         report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
 481 }
 482
 483 MonoNativeTlsKey thread_info_key;
 484
 485 #ifdef HAVE_KW_THREAD
 486 __thread SgenThreadInfo *sgen_thread_info;
 487 __thread char *stack_end;
 488 #endif
 489
 490 /* The size of a TLAB */
 491 /* The bigger the value, the less often we have to go to the slow path to allocate a new
 492  * one, but the more space is wasted by threads not allocating much memory.
 493  * FIXME: Tune this.
 494  * FIXME: Make this self-tuning for each thread.
 495  */
 496 guint32 tlab_size = (1024 * 4);
 497
 498 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
 499
 500 /* Functions supplied by the runtime to be called by the GC */
 501 static MonoGCCallbacks gc_callbacks;
 502
 503 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
 504 #define ALLOC_ALIGN_BITS        SGEN_ALLOC_ALIGN_BITS
 505
 506 #define ALIGN_UP                SGEN_ALIGN_UP
 507
 508 #define MOVED_OBJECTS_NUM 64
 509 static void *moved_objects [MOVED_OBJECTS_NUM];
 510 static int moved_objects_idx = 0;
 511
 512 /* Vtable of the objects used to fill out nursery fragments before a collection */
 513 static MonoVTable *array_fill_vtable;
 514
 515 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
 516 MonoNativeThreadId main_gc_thread = NULL;
 517 #endif
 518
 519 /*Object was pinned during the current collection*/
 520 static mword objects_pinned;
 521
 522 /*
 523  * ######################################################################
 524  * ########  Macros and function declarations.
 525  * ######################################################################
 526  */
 527
 528 inline static void*
 529 align_pointer (void *ptr)
 530 {
 531         mword p = (mword)ptr;
 532         p += sizeof (gpointer) - 1;
 533         p &= ~ (sizeof (gpointer) - 1);
 534         return (void*)p;
 535 }
 536
 537 typedef SgenGrayQueue GrayQueue;
 538
 539 /* forward declarations */
 540 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
 541 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
 542 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
 543 static void report_finalizer_roots (void);
 544 static void report_registered_roots (void);
 545
 546 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
 547 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
 548 static void finish_gray_stack (char *start_addr, char *end_addr, int generation, GrayQueue *queue);
 549
 550 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
 551
 552
 553 static void init_stats (void);
 554
 555 static int mark_ephemerons_in_range (ScanCopyContext ctx);
 556 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
 557 static void null_ephemerons_for_domain (MonoDomain *domain);
 558
 559 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
 560
 561 SgenObjectOperations current_object_ops;
 562 SgenMajorCollector major_collector;
 563 SgenMinorCollector sgen_minor_collector;
 564 static GrayQueue gray_queue;
 565
 566 static SgenRemeberedSet remset;
 567
 568 /* The gray queue to use from the main collection thread. */
 569 #define WORKERS_DISTRIBUTE_GRAY_QUEUE   (&gray_queue)
 570
 571 /*
 572  * The gray queue a worker job must use.  If we're not parallel or
 573  * concurrent, we use the main gray queue.
 574  */
 575 static SgenGrayQueue*
 576 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
 577 {
 578         return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
 579 }
 580
 581 static void
 582 gray_queue_redirect (SgenGrayQueue *queue)
 583 {
 584         gboolean wake = FALSE;
 585
 586
 587         for (;;) {
 588                 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
 589                 if (!section)
 590                         break;
 591                 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
 592                 wake = TRUE;
 593         }
 594
 595         if (wake) {
 596                 g_assert (concurrent_collection_in_progress ||
 597                                 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
 598                 if (sgen_workers_have_started ()) {
 599                         sgen_workers_wake_up_all ();
 600                 } else {
 601                         if (concurrent_collection_in_progress)
 602                                 g_assert (current_collection_generation == -1);
 603                 }
 604         }
 605 }
 606
 607 static gboolean
 608 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
 609 {
 610         MonoObject *o = (MonoObject*)(obj);
 611         MonoObject *ref = (MonoObject*)*(ptr);
 612         int offset = (char*)(ptr) - (char*)o;
 613
 614         if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
 615                 return TRUE;
 616         if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
 617                 return TRUE;
 618
 619 #ifndef DISABLE_REMOTING
 620         if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
 621                         offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
 622                 return TRUE;
 623 #endif
 624         /* Thread.cached_culture_info */
 625         if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
 626                         !strcmp (ref->vtable->klass->name, "CultureInfo") &&
 627                         !strcmp(o->vtable->klass->name_space, "System") &&
 628                         !strcmp(o->vtable->klass->name, "Object[]"))
 629                 return TRUE;
 630         /*
 631          *  at System.IO.MemoryStream.InternalConstructor (byte[],int,int,bool,bool) [0x0004d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:121
 632          * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
 633          * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
 634          * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
 635          * at System.Runtime.Remoting.Messaging.MethodCall..ctor (System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/MethodCall.cs:87
 636          * at System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) [0x00018] in /home/schani/Work/novell/trunk/mcs/class/corlib/System/AppDomain.cs:1213
 637          * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
 638          * at System.Runtime.Remoting.Channels.CrossAppDomainSink.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00008] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Channels/CrossAppDomainChannel.cs:198
 639          * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
 640          */
 641         if (!strcmp (ref->vtable->klass->name_space, "System") &&
 642                         !strcmp (ref->vtable->klass->name, "Byte[]") &&
 643                         !strcmp (o->vtable->klass->name_space, "System.IO") &&
 644                         !strcmp (o->vtable->klass->name, "MemoryStream"))
 645                 return TRUE;
 646         /* append_job() in threadpool.c */
 647         if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
 648                         !strcmp (ref->vtable->klass->name, "AsyncResult") &&
 649                         !strcmp (o->vtable->klass->name_space, "System") &&
 650                         !strcmp (o->vtable->klass->name, "Object[]") &&
 651                         mono_thread_pool_is_queue_array ((MonoArray*) o))
 652                 return TRUE;
 653         return FALSE;
 654 }
 655
 656 static void
 657 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
 658 {
 659         MonoObject *o = (MonoObject*)(obj);
 660         MonoObject *ref = (MonoObject*)*(ptr);
 661         int offset = (char*)(ptr) - (char*)o;
 662         MonoClass *class;
 663         MonoClassField *field;
 664         char *str;
 665
 666         if (!ref || ref->vtable->domain == domain)
 667                 return;
 668         if (is_xdomain_ref_allowed (ptr, obj, domain))
 669                 return;
 670
 671         field = NULL;
 672         for (class = o->vtable->klass; class; class = class->parent) {
 673                 int i;
 674
 675                 for (i = 0; i < class->field.count; ++i) {
 676                         if (class->fields[i].offset == offset) {
 677                                 field = &class->fields[i];
 678                                 break;
 679                         }
 680                 }
 681                 if (field)
 682                         break;
 683         }
 684
 685         if (ref->vtable->klass == mono_defaults.string_class)
 686                 str = mono_string_to_utf8 ((MonoString*)ref);
 687         else
 688                 str = NULL;
 689         g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s)  -  pointed to by:\n",
 690                         o, o->vtable->klass->name_space, o->vtable->klass->name,
 691                         offset, field ? field->name : "",
 692                         ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
 693         mono_gc_scan_for_specific_ref (o, TRUE);
 694         if (str)
 695                 g_free (str);
 696 }
 697
 698 #undef HANDLE_PTR
 699 #define HANDLE_PTR(ptr,obj)     check_reference_for_xdomain ((ptr), (obj), domain)
 700
 701 static void
 702 scan_object_for_xdomain_refs (char *start, mword size, void *data)
 703 {
 704         MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
 705
 706         #include "sgen-scan-object.h"
 707 }
 708
 709 static gboolean scan_object_for_specific_ref_precise = TRUE;
 710
 711 #undef HANDLE_PTR
 712 #define HANDLE_PTR(ptr,obj) do {                \
 713         if ((MonoObject*)*(ptr) == key) {       \
 714         g_print ("found ref to %p in object %p (%s) at offset %td\n",   \
 715                         key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
 716         }                                                               \
 717         } while (0)
 718
 719 static void
 720 scan_object_for_specific_ref (char *start, MonoObject *key)
 721 {
 722         char *forwarded;
 723
 724         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
 725                 start = forwarded;
 726
 727         if (scan_object_for_specific_ref_precise) {
 728                 #include "sgen-scan-object.h"
 729         } else {
 730                 mword *words = (mword*)start;
 731                 size_t size = safe_object_get_size ((MonoObject*)start);
 732                 int i;
 733                 for (i = 0; i < size / sizeof (mword); ++i) {
 734                         if (words [i] == (mword)key) {
 735                                 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
 736                                                 key, start, safe_name (start), i * sizeof (mword));
 737                         }
 738                 }
 739         }
 740 }
 741
 742 void
 743 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
 744 {
 745         while (start < end) {
 746                 size_t size;
 747                 char *obj;
 748
 749                 if (!*(void**)start) {
 750                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
 751                         continue;
 752                 }
 753
 754                 if (allow_flags) {
 755                         if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
 756                                 obj = start;
 757                 } else {
 758                         obj = start;
 759                 }
 760
 761                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
 762
 763                 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
 764                         callback (obj, size, data);
 765
 766                 start += size;
 767         }
 768 }
 769
 770 static void
 771 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
 772 {
 773         scan_object_for_specific_ref (obj, key);
 774 }
 775
 776 static void
 777 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
 778 {
 779         if (key != obj)
 780                 return;
 781         g_print ("found ref to %p in root record %p\n", key, root);
 782 }
 783
 784 static MonoObject *check_key = NULL;
 785 static RootRecord *check_root = NULL;
 786
 787 static void
 788 check_root_obj_specific_ref_from_marker (void **obj)
 789 {
 790         check_root_obj_specific_ref (check_root, check_key, *obj);
 791 }
 792
 793 static void
 794 scan_roots_for_specific_ref (MonoObject *key, int root_type)
 795 {
 796         void **start_root;
 797         RootRecord *root;
 798         check_key = key;
 799
 800         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 801                 mword desc = root->root_desc;
 802
 803                 check_root = root;
 804
 805                 switch (desc & ROOT_DESC_TYPE_MASK) {
 806                 case ROOT_DESC_BITMAP:
 807                         desc >>= ROOT_DESC_TYPE_SHIFT;
 808                         while (desc) {
 809                                 if (desc & 1)
 810                                         check_root_obj_specific_ref (root, key, *start_root);
 811                                 desc >>= 1;
 812                                 start_root++;
 813                         }
 814                         return;
 815                 case ROOT_DESC_COMPLEX: {
 816                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 817                         int bwords = (*bitmap_data) - 1;
 818                         void **start_run = start_root;
 819                         bitmap_data++;
 820                         while (bwords-- > 0) {
 821                                 gsize bmap = *bitmap_data++;
 822                                 void **objptr = start_run;
 823                                 while (bmap) {
 824                                         if (bmap & 1)
 825                                                 check_root_obj_specific_ref (root, key, *objptr);
 826                                         bmap >>= 1;
 827                                         ++objptr;
 828                                 }
 829                                 start_run += GC_BITS_PER_WORD;
 830                         }
 831                         break;
 832                 }
 833                 case ROOT_DESC_USER: {
 834                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 835                         marker (start_root, check_root_obj_specific_ref_from_marker);
 836                         break;
 837                 }
 838                 case ROOT_DESC_RUN_LEN:
 839                         g_assert_not_reached ();
 840                 default:
 841                         g_assert_not_reached ();
 842                 }
 843         } SGEN_HASH_TABLE_FOREACH_END;
 844
 845         check_key = NULL;
 846         check_root = NULL;
 847 }
 848
 849 void
 850 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
 851 {
 852         void **ptr;
 853         RootRecord *root;
 854
 855         scan_object_for_specific_ref_precise = precise;
 856
 857         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 858                         (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
 859
 860         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 861
 862         sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 863
 864         scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
 865         scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
 866
 867         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
 868                 while (ptr < (void**)root->end_root) {
 869                         check_root_obj_specific_ref (root, *ptr, key);
 870                         ++ptr;
 871                 }
 872         } SGEN_HASH_TABLE_FOREACH_END;
 873 }
 874
 875 static gboolean
 876 need_remove_object_for_domain (char *start, MonoDomain *domain)
 877 {
 878         if (mono_object_domain (start) == domain) {
 879                 SGEN_LOG (4, "Need to cleanup object %p", start);
 880                 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
 881                 return TRUE;
 882         }
 883         return FALSE;
 884 }
 885
 886 static void
 887 process_object_for_domain_clearing (char *start, MonoDomain *domain)
 888 {
 889         GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
 890         if (vt->klass == mono_defaults.internal_thread_class)
 891                 g_assert (mono_object_domain (start) == mono_get_root_domain ());
 892         /* The object could be a proxy for an object in the domain
 893            we're deleting. */
 894 #ifndef DISABLE_REMOTING
 895         if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
 896                 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
 897
 898                 /* The server could already have been zeroed out, so
 899                    we need to check for that, too. */
 900                 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
 901                         SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
 902                         ((MonoRealProxy*)start)->unwrapped_server = NULL;
 903                 }
 904         }
 905 #endif
 906 }
 907
 908 static MonoDomain *check_domain = NULL;
 909
 910 static void
 911 check_obj_not_in_domain (void **o)
 912 {
 913         g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
 914 }
 915
 916 static void
 917 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
 918 {
 919         void **start_root;
 920         RootRecord *root;
 921         check_domain = domain;
 922         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 923                 mword desc = root->root_desc;
 924
 925                 /* The MonoDomain struct is allowed to hold
 926                    references to objects in its own domain. */
 927                 if (start_root == (void**)domain)
 928                         continue;
 929
 930                 switch (desc & ROOT_DESC_TYPE_MASK) {
 931                 case ROOT_DESC_BITMAP:
 932                         desc >>= ROOT_DESC_TYPE_SHIFT;
 933                         while (desc) {
 934                                 if ((desc & 1) && *start_root)
 935                                         check_obj_not_in_domain (*start_root);
 936                                 desc >>= 1;
 937                                 start_root++;
 938                         }
 939                         break;
 940                 case ROOT_DESC_COMPLEX: {
 941                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 942                         int bwords = (*bitmap_data) - 1;
 943                         void **start_run = start_root;
 944                         bitmap_data++;
 945                         while (bwords-- > 0) {
 946                                 gsize bmap = *bitmap_data++;
 947                                 void **objptr = start_run;
 948                                 while (bmap) {
 949                                         if ((bmap & 1) && *objptr)
 950                                                 check_obj_not_in_domain (*objptr);
 951                                         bmap >>= 1;
 952                                         ++objptr;
 953                                 }
 954                                 start_run += GC_BITS_PER_WORD;
 955                         }
 956                         break;
 957                 }
 958                 case ROOT_DESC_USER: {
 959                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 960                         marker (start_root, check_obj_not_in_domain);
 961                         break;
 962                 }
 963                 case ROOT_DESC_RUN_LEN:
 964                         g_assert_not_reached ();
 965                 default:
 966                         g_assert_not_reached ();
 967                 }
 968         } SGEN_HASH_TABLE_FOREACH_END;
 969
 970         check_domain = NULL;
 971 }
 972
 973 static void
 974 check_for_xdomain_refs (void)
 975 {
 976         LOSObject *bigobj;
 977
 978         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 979                         (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
 980
 981         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
 982
 983         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
 984                 scan_object_for_xdomain_refs (bigobj->data, sgen_los_object_size (bigobj), NULL);
 985 }
 986
 987 static gboolean
 988 clear_domain_process_object (char *obj, MonoDomain *domain)
 989 {
 990         gboolean remove;
 991
 992         process_object_for_domain_clearing (obj, domain);
 993         remove = need_remove_object_for_domain (obj, domain);
 994
 995         if (remove && ((MonoObject*)obj)->synchronisation) {
 996                 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
 997                 if (dislink)
 998                         sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
 999         }
1000
1001         return remove;
1002 }
1003
1004 static void
1005 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1006 {
1007         if (clear_domain_process_object (obj, domain))
1008                 memset (obj, 0, size);
1009 }
1010
1011 static void
1012 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1013 {
1014         clear_domain_process_object (obj, domain);
1015 }
1016
1017 static void
1018 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1019 {
1020         if (need_remove_object_for_domain (obj, domain))
1021                 major_collector.free_non_pinned_object (obj, size);
1022 }
1023
1024 static void
1025 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1026 {
1027         if (need_remove_object_for_domain (obj, domain))
1028                 major_collector.free_pinned_object (obj, size);
1029 }
1030
1031 /*
1032  * When appdomains are unloaded we can easily remove objects that have finalizers,
1033  * but all the others could still be present in random places on the heap.
1034  * We need a sweep to get rid of them even though it's going to be costly
1035  * with big heaps.
1036  * The reason we need to remove them is because we access the vtable and class
1037  * structures to know the object size and the reference bitmap: once the domain is
1038  * unloaded the point to random memory.
1039  */
1040 void
1041 mono_gc_clear_domain (MonoDomain * domain)
1042 {
1043         LOSObject *bigobj, *prev;
1044         int i;
1045
1046         LOCK_GC;
1047
1048         if (concurrent_collection_in_progress)
1049                 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
1050         g_assert (!concurrent_collection_in_progress);
1051
1052         sgen_process_fin_stage_entries ();
1053         sgen_process_dislink_stage_entries ();
1054
1055         sgen_clear_nursery_fragments ();
1056
1057         if (xdomain_checks && domain != mono_get_root_domain ()) {
1058                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1059                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1060                 check_for_xdomain_refs ();
1061         }
1062
1063         /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1064         to memory returned to the OS.*/
1065         null_ephemerons_for_domain (domain);
1066
1067         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1068                 sgen_null_links_for_domain (domain, i);
1069
1070         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1071                 sgen_remove_finalizers_for_domain (domain, i);
1072
1073         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1074                         (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1075
1076         /* We need two passes over major and large objects because
1077            freeing such objects might give their memory back to the OS
1078            (in the case of large objects) or obliterate its vtable
1079            (pinned objects with major-copying or pinned and non-pinned
1080            objects with major-mark&sweep), but we might need to
1081            dereference a pointer from an object to another object if
1082            the first object is a proxy. */
1083         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1084         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1085                 clear_domain_process_object (bigobj->data, domain);
1086
1087         prev = NULL;
1088         for (bigobj = los_object_list; bigobj;) {
1089                 if (need_remove_object_for_domain (bigobj->data, domain)) {
1090                         LOSObject *to_free = bigobj;
1091                         if (prev)
1092                                 prev->next = bigobj->next;
1093                         else
1094                                 los_object_list = bigobj->next;
1095                         bigobj = bigobj->next;
1096                         SGEN_LOG (4, "Freeing large object %p", bigobj->data);
1097                         sgen_los_free_object (to_free);
1098                         continue;
1099                 }
1100                 prev = bigobj;
1101                 bigobj = bigobj->next;
1102         }
1103         major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1104         major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1105
1106         if (G_UNLIKELY (do_pin_stats)) {
1107                 if (domain == mono_get_root_domain ())
1108                         sgen_pin_stats_print_class_stats ();
1109         }
1110
1111         UNLOCK_GC;
1112 }
1113
1114 /*
1115  * sgen_add_to_global_remset:
1116  *
1117  *   The global remset contains locations which point into newspace after
1118  * a minor collection. This can happen if the objects they point to are pinned.
1119  *
1120  * LOCKING: If called from a parallel collector, the global remset
1121  * lock must be held.  For serial collectors that is not necessary.
1122  */
1123 void
1124 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
1125 {
1126         SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
1127
1128         HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
1129
1130         if (!major_collector.is_concurrent) {
1131                 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
1132         } else {
1133                 if (current_collection_generation == -1)
1134                         SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
1135         }
1136
1137         if (!object_is_pinned (obj))
1138                 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
1139         else if (sgen_cement_lookup_or_register (obj))
1140                 return;
1141
1142         remset.record_pointer (ptr);
1143
1144         if (G_UNLIKELY (do_pin_stats))
1145                 sgen_pin_stats_register_global_remset (obj);
1146
1147         SGEN_LOG (8, "Adding global remset for %p", ptr);
1148         binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
1149
1150
1151 #ifdef ENABLE_DTRACE
1152         if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
1153                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
1154                 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
1155                                 vt->klass->name_space, vt->klass->name);
1156         }
1157 #endif
1158 }
1159
1160 /*
1161  * sgen_drain_gray_stack:
1162  *
1163  *   Scan objects in the gray stack until the stack is empty. This should be called
1164  * frequently after each object is copied, to achieve better locality and cache
1165  * usage.
1166  */
1167 gboolean
1168 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
1169 {
1170         char *obj;
1171         ScanObjectFunc scan_func = ctx.scan_func;
1172         GrayQueue *queue = ctx.queue;
1173
1174         if (max_objs == -1) {
1175                 for (;;) {
1176                         GRAY_OBJECT_DEQUEUE (queue, obj);
1177                         if (!obj)
1178                                 return TRUE;
1179                         SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1180                         scan_func (obj, queue);
1181                 }
1182         } else {
1183                 int i;
1184
1185                 do {
1186                         for (i = 0; i != max_objs; ++i) {
1187                                 GRAY_OBJECT_DEQUEUE (queue, obj);
1188                                 if (!obj)
1189                                         return TRUE;
1190                                 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1191                                 scan_func (obj, queue);
1192                         }
1193                 } while (max_objs < 0);
1194                 return FALSE;
1195         }
1196 }
1197
1198 /*
1199  * Addresses from start to end are already sorted. This function finds
1200  * the object header for each address and pins the object. The
1201  * addresses must be inside the passed section.  The (start of the)
1202  * address array is overwritten with the addresses of the actually
1203  * pinned objects.  Return the number of pinned objects.
1204  */
1205 static int
1206 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1207 {
1208         void *last = NULL;
1209         int count = 0;
1210         void *search_start;
1211         void *last_obj = NULL;
1212         size_t last_obj_size = 0;
1213         void *addr;
1214         int idx;
1215         void **definitely_pinned = start;
1216         ScanObjectFunc scan_func = ctx.scan_func;
1217         SgenGrayQueue *queue = ctx.queue;
1218
1219         sgen_nursery_allocator_prepare_for_pinning ();
1220
1221         while (start < end) {
1222                 addr = *start;
1223                 /* the range check should be reduntant */
1224                 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1225                         SGEN_LOG (5, "Considering pinning addr %p", addr);
1226                         /* multiple pointers to the same object */
1227                         if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1228                                 start++;
1229                                 continue;
1230                         }
1231                         idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1232                         g_assert (idx < section->num_scan_start);
1233                         search_start = (void*)section->scan_starts [idx];
1234                         if (!search_start || search_start > addr) {
1235                                 while (idx) {
1236                                         --idx;
1237                                         search_start = section->scan_starts [idx];
1238                                         if (search_start && search_start <= addr)
1239                                                 break;
1240                                 }
1241                                 if (!search_start || search_start > addr)
1242                                         search_start = start_nursery;
1243                         }
1244                         if (search_start < last_obj)
1245                                 search_start = (char*)last_obj + last_obj_size;
1246                         /* now addr should be in an object a short distance from search_start
1247                          * Note that search_start must point to zeroed mem or point to an object.
1248                          */
1249
1250                         do {
1251                                 if (!*(void**)search_start) {
1252                                         /* Consistency check */
1253                                         /*
1254                                         for (frag = nursery_fragments; frag; frag = frag->next) {
1255                                                 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1256                                                         g_assert_not_reached ();
1257                                         }
1258                                         */
1259
1260                                         search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1261                                         continue;
1262                                 }
1263                                 last_obj = search_start;
1264                                 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1265
1266                                 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1267                                         /* Marks the beginning of a nursery fragment, skip */
1268                                 } else {
1269                                         SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
1270                                         if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1271                                                 if (scan_func) {
1272                                                         scan_func (search_start, queue);
1273                                                 } else {
1274                                                         SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1275                                                                         search_start, *(void**)search_start, safe_name (search_start), count);
1276                                                         binary_protocol_pin (search_start,
1277                                                                         (gpointer)LOAD_VTABLE (search_start),
1278                                                                         safe_object_get_size (search_start));
1279
1280 #ifdef ENABLE_DTRACE
1281                                                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1282                                                                 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
1283                                                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
1284                                                                 MONO_GC_OBJ_PINNED ((mword)search_start,
1285                                                                                 sgen_safe_object_get_size (search_start),
1286                                                                                 vt->klass->name_space, vt->klass->name, gen);
1287                                                         }
1288 #endif
1289
1290                                                         pin_object (search_start);
1291                                                         GRAY_OBJECT_ENQUEUE (queue, search_start);
1292                                                         if (G_UNLIKELY (do_pin_stats))
1293                                                                 sgen_pin_stats_register_object (search_start, last_obj_size);
1294                                                         definitely_pinned [count] = search_start;
1295                                                         count++;
1296                                                 }
1297                                                 break;
1298                                         }
1299                                 }
1300                                 /* skip to the next object */
1301                                 search_start = (void*)((char*)search_start + last_obj_size);
1302                         } while (search_start <= addr);
1303                         /* we either pinned the correct object or we ignored the addr because
1304                          * it points to unused zeroed memory.
1305                          */
1306                         last = addr;
1307                 }
1308                 start++;
1309         }
1310         //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1311         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1312                 GCRootReport report;
1313                 report.count = 0;
1314                 for (idx = 0; idx < count; ++idx)
1315                         add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1316                 notify_gc_roots (&report);
1317         }
1318         stat_pinned_objects += count;
1319         return count;
1320 }
1321
1322 void
1323 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1324 {
1325         int num_entries = section->pin_queue_num_entries;
1326         if (num_entries) {
1327                 void **start = section->pin_queue_start;
1328                 int reduced_to;
1329                 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1330                                 section->data, section->next_data, ctx);
1331                 section->pin_queue_num_entries = reduced_to;
1332                 if (!reduced_to)
1333                         section->pin_queue_start = NULL;
1334         }
1335 }
1336
1337
1338 void
1339 sgen_pin_object (void *object, GrayQueue *queue)
1340 {
1341         g_assert (!concurrent_collection_in_progress);
1342
1343         if (sgen_collection_is_parallel ()) {
1344                 LOCK_PIN_QUEUE;
1345                 /*object arrives pinned*/
1346                 sgen_pin_stage_ptr (object);
1347                 ++objects_pinned ;
1348                 UNLOCK_PIN_QUEUE;
1349         } else {
1350                 SGEN_PIN_OBJECT (object);
1351                 sgen_pin_stage_ptr (object);
1352                 ++objects_pinned;
1353                 if (G_UNLIKELY (do_pin_stats))
1354                         sgen_pin_stats_register_object (object, safe_object_get_size (object));
1355         }
1356         GRAY_OBJECT_ENQUEUE (queue, object);
1357         binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1358
1359 #ifdef ENABLE_DTRACE
1360         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1361                 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1362                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1363                 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1364         }
1365 #endif
1366 }
1367
1368 void
1369 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1370 {
1371         for (;;) {
1372                 mword vtable_word;
1373                 gboolean major_pinned = FALSE;
1374
1375                 if (sgen_ptr_in_nursery (obj)) {
1376                         if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1377                                 sgen_pin_object (obj, queue);
1378                                 break;
1379                         }
1380                 } else {
1381                         major_collector.pin_major_object (obj, queue);
1382                         major_pinned = TRUE;
1383                 }
1384
1385                 vtable_word = *(mword*)obj;
1386                 /*someone else forwarded it, update the pointer and bail out*/
1387                 if (vtable_word & SGEN_FORWARDED_BIT) {
1388                         *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1389                         break;
1390                 }
1391
1392                 /*someone pinned it, nothing to do.*/
1393                 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1394                         break;
1395         }
1396 }
1397
1398 /* Sort the addresses in array in increasing order.
1399  * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1400  */
1401 void
1402 sgen_sort_addresses (void **array, int size)
1403 {
1404         int i;
1405         void *tmp;
1406
1407         for (i = 1; i < size; ++i) {
1408                 int child = i;
1409                 while (child > 0) {
1410                         int parent = (child - 1) / 2;
1411
1412                         if (array [parent] >= array [child])
1413                                 break;
1414
1415                         tmp = array [parent];
1416                         array [parent] = array [child];
1417                         array [child] = tmp;
1418
1419                         child = parent;
1420                 }
1421         }
1422
1423         for (i = size - 1; i > 0; --i) {
1424                 int end, root;
1425                 tmp = array [i];
1426                 array [i] = array [0];
1427                 array [0] = tmp;
1428
1429                 end = i - 1;
1430                 root = 0;
1431
1432                 while (root * 2 + 1 <= end) {
1433                         int child = root * 2 + 1;
1434
1435                         if (child < end && array [child] < array [child + 1])
1436                                 ++child;
1437                         if (array [root] >= array [child])
1438                                 break;
1439
1440                         tmp = array [root];
1441                         array [root] = array [child];
1442                         array [child] = tmp;
1443
1444                         root = child;
1445                 }
1446         }
1447 }
1448
1449 /*
1450  * Scan the memory between start and end and queue values which could be pointers
1451  * to the area between start_nursery and end_nursery for later consideration.
1452  * Typically used for thread stacks.
1453  */
1454 static void
1455 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1456 {
1457         int count = 0;
1458
1459 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1460         VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1461 #endif
1462
1463         while (start < end) {
1464                 if (*start >= start_nursery && *start < end_nursery) {
1465                         /*
1466                          * *start can point to the middle of an object
1467                          * note: should we handle pointing at the end of an object?
1468                          * pinning in C# code disallows pointing at the end of an object
1469                          * but there is some small chance that an optimizing C compiler
1470                          * may keep the only reference to an object by pointing
1471                          * at the end of it. We ignore this small chance for now.
1472                          * Pointers to the end of an object are indistinguishable
1473                          * from pointers to the start of the next object in memory
1474                          * so if we allow that we'd need to pin two objects...
1475                          * We queue the pointer in an array, the
1476                          * array will then be sorted and uniqued. This way
1477                          * we can coalesce several pinning pointers and it should
1478                          * be faster since we'd do a memory scan with increasing
1479                          * addresses. Note: we can align the address to the allocation
1480                          * alignment, so the unique process is more effective.
1481                          */
1482                         mword addr = (mword)*start;
1483                         addr &= ~(ALLOC_ALIGN - 1);
1484                         if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1485                                 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1486                                 sgen_pin_stage_ptr ((void*)addr);
1487                                 count++;
1488                         }
1489                         if (G_UNLIKELY (do_pin_stats)) {
1490                                 if (ptr_in_nursery ((void*)addr))
1491                                         sgen_pin_stats_register_address ((char*)addr, pin_type);
1492                         }
1493                 }
1494                 start++;
1495         }
1496         if (count)
1497                 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1498 }
1499
1500 /*
1501  * The first thing we do in a collection is to identify pinned objects.
1502  * This function considers all the areas of memory that need to be
1503  * conservatively scanned.
1504  */
1505 static void
1506 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1507 {
1508         void **start_root;
1509         RootRecord *root;
1510         SGEN_LOG (2, "Scanning pinned roots (%d bytes, %d/%d entries)", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries);
1511         /* objects pinned from the API are inside these roots */
1512         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1513                 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1514                 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1515         } SGEN_HASH_TABLE_FOREACH_END;
1516         /* now deal with the thread stacks
1517          * in the future we should be able to conservatively scan only:
1518          * *) the cpu registers
1519          * *) the unmanaged stack frames
1520          * *) the _last_ managed stack frame
1521          * *) pointers slots in managed frames
1522          */
1523         scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1524 }
1525
1526 static void
1527 unpin_objects_from_queue (SgenGrayQueue *queue)
1528 {
1529         for (;;) {
1530                 char *addr;
1531                 GRAY_OBJECT_DEQUEUE (queue, addr);
1532                 if (!addr)
1533                         break;
1534                 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1535                 SGEN_UNPIN_OBJECT (addr);
1536         }
1537 }
1538
1539 typedef struct {
1540         CopyOrMarkObjectFunc func;
1541         GrayQueue *queue;
1542 } UserCopyOrMarkData;
1543
1544 static MonoNativeTlsKey user_copy_or_mark_key;
1545
1546 static void
1547 init_user_copy_or_mark_key (void)
1548 {
1549         mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1550 }
1551
1552 static void
1553 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1554 {
1555         mono_native_tls_set_value (user_copy_or_mark_key, data);
1556 }
1557
1558 static void
1559 single_arg_user_copy_or_mark (void **obj)
1560 {
1561         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1562
1563         data->func (obj, data->queue);
1564 }
1565
1566 /*
1567  * The memory area from start_root to end_root contains pointers to objects.
1568  * Their position is precisely described by @desc (this means that the pointer
1569  * can be either NULL or the pointer to the start of an object).
1570  * This functions copies them to to_space updates them.
1571  *
1572  * This function is not thread-safe!
1573  */
1574 static void
1575 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1576 {
1577         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1578         SgenGrayQueue *queue = ctx.queue;
1579
1580         switch (desc & ROOT_DESC_TYPE_MASK) {
1581         case ROOT_DESC_BITMAP:
1582                 desc >>= ROOT_DESC_TYPE_SHIFT;
1583                 while (desc) {
1584                         if ((desc & 1) && *start_root) {
1585                                 copy_func (start_root, queue);
1586                                 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1587                                 sgen_drain_gray_stack (-1, ctx);
1588                         }
1589                         desc >>= 1;
1590                         start_root++;
1591                 }
1592                 return;
1593         case ROOT_DESC_COMPLEX: {
1594                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1595                 int bwords = (*bitmap_data) - 1;
1596                 void **start_run = start_root;
1597                 bitmap_data++;
1598                 while (bwords-- > 0) {
1599                         gsize bmap = *bitmap_data++;
1600                         void **objptr = start_run;
1601                         while (bmap) {
1602                                 if ((bmap & 1) && *objptr) {
1603                                         copy_func (objptr, queue);
1604                                         SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1605                                         sgen_drain_gray_stack (-1, ctx);
1606                                 }
1607                                 bmap >>= 1;
1608                                 ++objptr;
1609                         }
1610                         start_run += GC_BITS_PER_WORD;
1611                 }
1612                 break;
1613         }
1614         case ROOT_DESC_USER: {
1615                 UserCopyOrMarkData data = { copy_func, queue };
1616                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1617                 set_user_copy_or_mark_data (&data);
1618                 marker (start_root, single_arg_user_copy_or_mark);
1619                 set_user_copy_or_mark_data (NULL);
1620                 break;
1621         }
1622         case ROOT_DESC_RUN_LEN:
1623                 g_assert_not_reached ();
1624         default:
1625                 g_assert_not_reached ();
1626         }
1627 }
1628
1629 static void
1630 reset_heap_boundaries (void)
1631 {
1632         lowest_heap_address = ~(mword)0;
1633         highest_heap_address = 0;
1634 }
1635
1636 void
1637 sgen_update_heap_boundaries (mword low, mword high)
1638 {
1639         mword old;
1640
1641         do {
1642                 old = lowest_heap_address;
1643                 if (low >= old)
1644                         break;
1645         } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1646
1647         do {
1648                 old = highest_heap_address;
1649                 if (high <= old)
1650                         break;
1651         } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1652 }
1653
1654 /*
1655  * Allocate and setup the data structures needed to be able to allocate objects
1656  * in the nursery. The nursery is stored in nursery_section.
1657  */
1658 static void
1659 alloc_nursery (void)
1660 {
1661         GCMemSection *section;
1662         char *data;
1663         int scan_starts;
1664         int alloc_size;
1665
1666         if (nursery_section)
1667                 return;
1668         SGEN_LOG (2, "Allocating nursery size: %lu", (unsigned long)sgen_nursery_size);
1669         /* later we will alloc a larger area for the nursery but only activate
1670          * what we need. The rest will be used as expansion if we have too many pinned
1671          * objects in the existing nursery.
1672          */
1673         /* FIXME: handle OOM */
1674         section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1675
1676         alloc_size = sgen_nursery_size;
1677
1678         /* If there isn't enough space even for the nursery we should simply abort. */
1679         g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1680
1681 #ifdef SGEN_ALIGN_NURSERY
1682         data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1683 #else
1684         data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1685 #endif
1686         sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1687         SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)mono_gc_get_heap_size ());
1688         section->data = section->next_data = data;
1689         section->size = alloc_size;
1690         section->end_data = data + sgen_nursery_size;
1691         scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1692         section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1693         section->num_scan_start = scan_starts;
1694
1695         nursery_section = section;
1696
1697         sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1698 }
1699
1700 void*
1701 mono_gc_get_nursery (int *shift_bits, size_t *size)
1702 {
1703         *size = sgen_nursery_size;
1704 #ifdef SGEN_ALIGN_NURSERY
1705         *shift_bits = DEFAULT_NURSERY_BITS;
1706 #else
1707         *shift_bits = -1;
1708 #endif
1709         return sgen_get_nursery_start ();
1710 }
1711
1712 void
1713 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1714 {
1715         SgenThreadInfo *info = mono_thread_info_current ();
1716
1717         /* Could be called from sgen_thread_unregister () with a NULL info */
1718         if (domain) {
1719                 g_assert (info);
1720                 info->stopped_domain = domain;
1721         }
1722 }
1723
1724 gboolean
1725 mono_gc_precise_stack_mark_enabled (void)
1726 {
1727         return !conservative_stack_mark;
1728 }
1729
1730 FILE *
1731 mono_gc_get_logfile (void)
1732 {
1733         return gc_debug_file;
1734 }
1735
1736 static void
1737 report_finalizer_roots_list (FinalizeReadyEntry *list)
1738 {
1739         GCRootReport report;
1740         FinalizeReadyEntry *fin;
1741
1742         report.count = 0;
1743         for (fin = list; fin; fin = fin->next) {
1744                 if (!fin->object)
1745                         continue;
1746                 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1747         }
1748         notify_gc_roots (&report);
1749 }
1750
1751 static void
1752 report_finalizer_roots (void)
1753 {
1754         report_finalizer_roots_list (fin_ready_list);
1755         report_finalizer_roots_list (critical_fin_list);
1756 }
1757
1758 static GCRootReport *root_report;
1759
1760 static void
1761 single_arg_report_root (void **obj)
1762 {
1763         if (*obj)
1764                 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1765 }
1766
1767 static void
1768 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1769 {
1770         switch (desc & ROOT_DESC_TYPE_MASK) {
1771         case ROOT_DESC_BITMAP:
1772                 desc >>= ROOT_DESC_TYPE_SHIFT;
1773                 while (desc) {
1774                         if ((desc & 1) && *start_root) {
1775                                 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1776                         }
1777                         desc >>= 1;
1778                         start_root++;
1779                 }
1780                 return;
1781         case ROOT_DESC_COMPLEX: {
1782                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1783                 int bwords = (*bitmap_data) - 1;
1784                 void **start_run = start_root;
1785                 bitmap_data++;
1786                 while (bwords-- > 0) {
1787                         gsize bmap = *bitmap_data++;
1788                         void **objptr = start_run;
1789                         while (bmap) {
1790                                 if ((bmap & 1) && *objptr) {
1791                                         add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1792                                 }
1793                                 bmap >>= 1;
1794                                 ++objptr;
1795                         }
1796                         start_run += GC_BITS_PER_WORD;
1797                 }
1798                 break;
1799         }
1800         case ROOT_DESC_USER: {
1801                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1802                 root_report = report;
1803                 marker (start_root, single_arg_report_root);
1804                 break;
1805         }
1806         case ROOT_DESC_RUN_LEN:
1807                 g_assert_not_reached ();
1808         default:
1809                 g_assert_not_reached ();
1810         }
1811 }
1812
1813 static void
1814 report_registered_roots_by_type (int root_type)
1815 {
1816         GCRootReport report;
1817         void **start_root;
1818         RootRecord *root;
1819         report.count = 0;
1820         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1821                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1822                 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1823         } SGEN_HASH_TABLE_FOREACH_END;
1824         notify_gc_roots (&report);
1825 }
1826
1827 static void
1828 report_registered_roots (void)
1829 {
1830         report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1831         report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1832 }
1833
1834 static void
1835 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1836 {
1837         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1838         SgenGrayQueue *queue = ctx.queue;
1839         FinalizeReadyEntry *fin;
1840
1841         for (fin = list; fin; fin = fin->next) {
1842                 if (!fin->object)
1843                         continue;
1844                 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1845                 copy_func (&fin->object, queue);
1846         }
1847 }
1848
1849 static const char*
1850 generation_name (int generation)
1851 {
1852         switch (generation) {
1853         case GENERATION_NURSERY: return "nursery";
1854         case GENERATION_OLD: return "old";
1855         default: g_assert_not_reached ();
1856         }
1857 }
1858
1859 const char*
1860 sgen_generation_name (int generation)
1861 {
1862         return generation_name (generation);
1863 }
1864
1865 SgenObjectOperations *
1866 sgen_get_current_object_ops (void){
1867         return &current_object_ops;
1868 }
1869
1870
1871 static void
1872 finish_gray_stack (char *start_addr, char *end_addr, int generation, GrayQueue *queue)
1873 {
1874         TV_DECLARE (atv);
1875         TV_DECLARE (btv);
1876         int done_with_ephemerons, ephemeron_rounds = 0;
1877         CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1878         ScanObjectFunc scan_func = current_object_ops.scan_object;
1879         ScanCopyContext ctx = { scan_func, copy_func, queue };
1880
1881         /*
1882          * We copied all the reachable objects. Now it's the time to copy
1883          * the objects that were not referenced by the roots, but by the copied objects.
1884          * we built a stack of objects pointed to by gray_start: they are
1885          * additional roots and we may add more items as we go.
1886          * We loop until gray_start == gray_objects which means no more objects have
1887          * been added. Note this is iterative: no recursion is involved.
1888          * We need to walk the LO list as well in search of marked big objects
1889          * (use a flag since this is needed only on major collections). We need to loop
1890          * here as well, so keep a counter of marked LO (increasing it in copy_object).
1891          *   To achieve better cache locality and cache usage, we drain the gray stack
1892          * frequently, after each object is copied, and just finish the work here.
1893          */
1894         sgen_drain_gray_stack (-1, ctx);
1895         TV_GETTIME (atv);
1896         SGEN_LOG (2, "%s generation done", generation_name (generation));
1897
1898         /*
1899         Reset bridge data, we might have lingering data from a previous collection if this is a major
1900         collection trigged by minor overflow.
1901
1902         We must reset the gathered bridges since their original block might be evacuated due to major
1903         fragmentation in the meanwhile and the bridge code should not have to deal with that.
1904         */
1905         sgen_bridge_reset_data ();
1906
1907         /*
1908          * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1909          * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1910          * objects that are in fact reachable.
1911          */
1912         done_with_ephemerons = 0;
1913         do {
1914                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1915                 sgen_drain_gray_stack (-1, ctx);
1916                 ++ephemeron_rounds;
1917         } while (!done_with_ephemerons);
1918
1919         sgen_scan_togglerefs (start_addr, end_addr, ctx);
1920         if (generation == GENERATION_OLD)
1921                 sgen_scan_togglerefs (sgen_get_nursery_start (), sgen_get_nursery_end (), ctx);
1922
1923         if (sgen_need_bridge_processing ()) {
1924                 sgen_collect_bridge_objects (generation, ctx);
1925                 if (generation == GENERATION_OLD)
1926                         sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1927         }
1928
1929         /*
1930         Make sure we drain the gray stack before processing disappearing links and finalizers.
1931         If we don't make sure it is empty we might wrongly see a live object as dead.
1932         */
1933         sgen_drain_gray_stack (-1, ctx);
1934
1935         /*
1936         We must clear weak links that don't track resurrection before processing object ready for
1937         finalization so they can be cleared before that.
1938         */
1939         sgen_null_link_in_range (generation, TRUE, ctx);
1940         if (generation == GENERATION_OLD)
1941                 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1942
1943
1944         /* walk the finalization queue and move also the objects that need to be
1945          * finalized: use the finalized objects as new roots so the objects they depend
1946          * on are also not reclaimed. As with the roots above, only objects in the nursery
1947          * are marked/copied.
1948          */
1949         sgen_finalize_in_range (generation, ctx);
1950         if (generation == GENERATION_OLD)
1951                 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1952         /* drain the new stack that might have been created */
1953         SGEN_LOG (6, "Precise scan of gray area post fin");
1954         sgen_drain_gray_stack (-1, ctx);
1955
1956         /*
1957          * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1958          */
1959         done_with_ephemerons = 0;
1960         do {
1961                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1962                 sgen_drain_gray_stack (-1, ctx);
1963                 ++ephemeron_rounds;
1964         } while (!done_with_ephemerons);
1965
1966         /*
1967          * Clear ephemeron pairs with unreachable keys.
1968          * We pass the copy func so we can figure out if an array was promoted or not.
1969          */
1970         clear_unreachable_ephemerons (ctx);
1971
1972         TV_GETTIME (btv);
1973         SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1974
1975         /*
1976          * handle disappearing links
1977          * Note we do this after checking the finalization queue because if an object
1978          * survives (at least long enough to be finalized) we don't clear the link.
1979          * This also deals with a possible issue with the monitor reclamation: with the Boehm
1980          * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1981          * called.
1982          */
1983         g_assert (sgen_gray_object_queue_is_empty (queue));
1984         for (;;) {
1985                 sgen_null_link_in_range (generation, FALSE, ctx);
1986                 if (generation == GENERATION_OLD)
1987                         sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1988                 if (sgen_gray_object_queue_is_empty (queue))
1989                         break;
1990                 sgen_drain_gray_stack (-1, ctx);
1991         }
1992
1993         g_assert (sgen_gray_object_queue_is_empty (queue));
1994 }
1995
1996 void
1997 sgen_check_section_scan_starts (GCMemSection *section)
1998 {
1999         int i;
2000         for (i = 0; i < section->num_scan_start; ++i) {
2001                 if (section->scan_starts [i]) {
2002                         guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2003                         g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2004                 }
2005         }
2006 }
2007
2008 static void
2009 check_scan_starts (void)
2010 {
2011         if (!do_scan_starts_check)
2012                 return;
2013         sgen_check_section_scan_starts (nursery_section);
2014         major_collector.check_scan_starts ();
2015 }
2016
2017 static void
2018 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
2019 {
2020         void **start_root;
2021         RootRecord *root;
2022         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2023                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
2024                 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
2025         } SGEN_HASH_TABLE_FOREACH_END;
2026 }
2027
2028 void
2029 sgen_dump_occupied (char *start, char *end, char *section_start)
2030 {
2031         fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2032 }
2033
2034 void
2035 sgen_dump_section (GCMemSection *section, const char *type)
2036 {
2037         char *start = section->data;
2038         char *end = section->data + section->size;
2039         char *occ_start = NULL;
2040         GCVTable *vt;
2041         char *old_start = NULL; /* just for debugging */
2042
2043         fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2044
2045         while (start < end) {
2046                 guint size;
2047                 MonoClass *class;
2048
2049                 if (!*(void**)start) {
2050                         if (occ_start) {
2051                                 sgen_dump_occupied (occ_start, start, section->data);
2052                                 occ_start = NULL;
2053                         }
2054                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2055                         continue;
2056                 }
2057                 g_assert (start < section->next_data);
2058
2059                 if (!occ_start)
2060                         occ_start = start;
2061
2062                 vt = (GCVTable*)LOAD_VTABLE (start);
2063                 class = vt->klass;
2064
2065                 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2066
2067                 /*
2068                 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2069                                 start - section->data,
2070                                 vt->klass->name_space, vt->klass->name,
2071                                 size);
2072                 */
2073
2074                 old_start = start;
2075                 start += size;
2076         }
2077         if (occ_start)
2078                 sgen_dump_occupied (occ_start, start, section->data);
2079
2080         fprintf (heap_dump_file, "</section>\n");
2081 }
2082
2083 static void
2084 dump_object (MonoObject *obj, gboolean dump_location)
2085 {
2086         static char class_name [1024];
2087
2088         MonoClass *class = mono_object_class (obj);
2089         int i, j;
2090
2091         /*
2092          * Python's XML parser is too stupid to parse angle brackets
2093          * in strings, so we just ignore them;
2094          */
2095         i = j = 0;
2096         while (class->name [i] && j < sizeof (class_name) - 1) {
2097                 if (!strchr ("<>\"", class->name [i]))
2098                         class_name [j++] = class->name [i];
2099                 ++i;
2100         }
2101         g_assert (j < sizeof (class_name));
2102         class_name [j] = 0;
2103
2104         fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2105                         class->name_space, class_name,
2106                         safe_object_get_size (obj));
2107         if (dump_location) {
2108                 const char *location;
2109                 if (ptr_in_nursery (obj))
2110                         location = "nursery";
2111                 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2112                         location = "major";
2113                 else
2114                         location = "LOS";
2115                 fprintf (heap_dump_file, " location=\"%s\"", location);
2116         }
2117         fprintf (heap_dump_file, "/>\n");
2118 }
2119
2120 static void
2121 dump_heap (const char *type, int num, const char *reason)
2122 {
2123         ObjectList *list;
2124         LOSObject *bigobj;
2125
2126         fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2127         if (reason)
2128                 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2129         fprintf (heap_dump_file, ">\n");
2130         fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2131         sgen_dump_internal_mem_usage (heap_dump_file);
2132         fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2133         /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2134         fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2135
2136         fprintf (heap_dump_file, "<pinned-objects>\n");
2137         for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2138                 dump_object (list->obj, TRUE);
2139         fprintf (heap_dump_file, "</pinned-objects>\n");
2140
2141         sgen_dump_section (nursery_section, "nursery");
2142
2143         major_collector.dump_heap (heap_dump_file);
2144
2145         fprintf (heap_dump_file, "<los>\n");
2146         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2147                 dump_object ((MonoObject*)bigobj->data, FALSE);
2148         fprintf (heap_dump_file, "</los>\n");
2149
2150         fprintf (heap_dump_file, "</collection>\n");
2151 }
2152
2153 void
2154 sgen_register_moved_object (void *obj, void *destination)
2155 {
2156         g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2157
2158         /* FIXME: handle this for parallel collector */
2159         g_assert (!sgen_collection_is_parallel ());
2160
2161         if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2162                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2163                 moved_objects_idx = 0;
2164         }
2165         moved_objects [moved_objects_idx++] = obj;
2166         moved_objects [moved_objects_idx++] = destination;
2167 }
2168
2169 static void
2170 init_stats (void)
2171 {
2172         static gboolean inited = FALSE;
2173
2174         if (inited)
2175                 return;
2176
2177         mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2178         mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2179         mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2180         mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2181         mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2182         mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2183         mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2184         mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2185
2186         mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2187         mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2188         mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2189         mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2190         mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2191         mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2192         mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2193         mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2194         mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2195         mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2196         mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2197         mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2198         mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2199
2200         mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2201
2202 #ifdef HEAVY_STATISTICS
2203         mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
2204         mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2205         mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2206         mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2207         mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2208         mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2209         mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2210         mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2211
2212         mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2213         mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2214
2215         mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2216         mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2217         mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2218         mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2219
2220         mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2221         mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2222
2223         mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2224
2225         mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2226         mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2227         mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2228         mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2229
2230         sgen_nursery_allocator_init_heavy_stats ();
2231         sgen_alloc_init_heavy_stats ();
2232 #endif
2233
2234         inited = TRUE;
2235 }
2236
2237
2238 static void
2239 reset_pinned_from_failed_allocation (void)
2240 {
2241         bytes_pinned_from_failed_allocation = 0;
2242 }
2243
2244 void
2245 sgen_set_pinned_from_failed_allocation (mword objsize)
2246 {
2247         bytes_pinned_from_failed_allocation += objsize;
2248 }
2249
2250 gboolean
2251 sgen_collection_is_parallel (void)
2252 {
2253         switch (current_collection_generation) {
2254         case GENERATION_NURSERY:
2255                 return nursery_collection_is_parallel;
2256         case GENERATION_OLD:
2257                 return major_collector.is_parallel;
2258         default:
2259                 g_error ("Invalid current generation %d", current_collection_generation);
2260         }
2261 }
2262
2263 gboolean
2264 sgen_collection_is_concurrent (void)
2265 {
2266         switch (current_collection_generation) {
2267         case GENERATION_NURSERY:
2268                 return FALSE;
2269         case GENERATION_OLD:
2270                 return concurrent_collection_in_progress;
2271         default:
2272                 g_error ("Invalid current generation %d", current_collection_generation);
2273         }
2274 }
2275
2276 gboolean
2277 sgen_concurrent_collection_in_progress (void)
2278 {
2279         return concurrent_collection_in_progress;
2280 }
2281
2282 typedef struct
2283 {
2284         char *heap_start;
2285         char *heap_end;
2286 } FinishRememberedSetScanJobData;
2287
2288 static void
2289 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2290 {
2291         FinishRememberedSetScanJobData *job_data = job_data_untyped;
2292
2293         remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2294         sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2295 }
2296
2297 typedef struct
2298 {
2299         CopyOrMarkObjectFunc copy_or_mark_func;
2300         ScanObjectFunc scan_func;
2301         char *heap_start;
2302         char *heap_end;
2303         int root_type;
2304 } ScanFromRegisteredRootsJobData;
2305
2306 static void
2307 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2308 {
2309         ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2310         ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2311                 sgen_workers_get_job_gray_queue (worker_data) };
2312
2313         scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2314         sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2315 }
2316
2317 typedef struct
2318 {
2319         char *heap_start;
2320         char *heap_end;
2321 } ScanThreadDataJobData;
2322
2323 static void
2324 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2325 {
2326         ScanThreadDataJobData *job_data = job_data_untyped;
2327
2328         scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2329                         sgen_workers_get_job_gray_queue (worker_data));
2330         sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2331 }
2332
2333 typedef struct
2334 {
2335         FinalizeReadyEntry *list;
2336 } ScanFinalizerEntriesJobData;
2337
2338 static void
2339 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2340 {
2341         ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2342         ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2343
2344         scan_finalizer_entries (job_data->list, ctx);
2345         sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2346 }
2347
2348 static void
2349 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2350 {
2351         g_assert (concurrent_collection_in_progress);
2352         major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2353 }
2354
2355 static void
2356 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2357 {
2358         g_assert (concurrent_collection_in_progress);
2359         sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2360 }
2361
2362 static void
2363 verify_scan_starts (char *start, char *end)
2364 {
2365         int i;
2366
2367         for (i = 0; i < nursery_section->num_scan_start; ++i) {
2368                 char *addr = nursery_section->scan_starts [i];
2369                 if (addr > start && addr < end)
2370                         SGEN_LOG (1, "NFC-BAD SCAN START [%d] %p for obj [%p %p]", i, addr, start, end);
2371         }
2372 }
2373
2374 static void
2375 verify_nursery (void)
2376 {
2377         char *start, *end, *cur, *hole_start;
2378
2379         if (!do_verify_nursery)
2380                 return;
2381
2382         /*This cleans up unused fragments */
2383         sgen_nursery_allocator_prepare_for_pinning ();
2384
2385         hole_start = start = cur = sgen_get_nursery_start ();
2386         end = sgen_get_nursery_end ();
2387
2388         while (cur < end) {
2389                 size_t ss, size;
2390
2391                 if (!*(void**)cur) {
2392                         cur += sizeof (void*);
2393                         continue;
2394                 }
2395
2396                 if (object_is_forwarded (cur))
2397                         SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2398                 else if (object_is_pinned (cur))
2399                         SGEN_LOG (1, "PINNED OBJ %p", cur);
2400
2401                 ss = safe_object_get_size ((MonoObject*)cur);
2402                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2403                 verify_scan_starts (cur, cur + size);
2404                 if (do_dump_nursery_content) {
2405                         if (cur > hole_start)
2406                                 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2407                         SGEN_LOG (1, "OBJ  [%p %p %d %d %s %d]", cur, cur + size, (int)size, (int)ss, sgen_safe_name ((MonoObject*)cur), (gpointer)LOAD_VTABLE (cur) == sgen_get_array_fill_vtable ());
2408                 }
2409                 cur += size;
2410                 hole_start = cur;
2411         }
2412 }
2413
2414 /*
2415  * Checks that no objects in the nursery are fowarded or pinned.  This
2416  * is a precondition to restarting the mutator while doing a
2417  * concurrent collection.  Note that we don't clear fragments because
2418  * we depend on that having happened earlier.
2419  */
2420 static void
2421 check_nursery_is_clean (void)
2422 {
2423         char *start, *end, *cur;
2424
2425         start = cur = sgen_get_nursery_start ();
2426         end = sgen_get_nursery_end ();
2427
2428         while (cur < end) {
2429                 size_t ss, size;
2430
2431                 if (!*(void**)cur) {
2432                         cur += sizeof (void*);
2433                         continue;
2434                 }
2435
2436                 g_assert (!object_is_forwarded (cur));
2437                 g_assert (!object_is_pinned (cur));
2438
2439                 ss = safe_object_get_size ((MonoObject*)cur);
2440                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2441                 verify_scan_starts (cur, cur + size);
2442
2443                 cur += size;
2444         }
2445 }
2446
2447 static void
2448 init_gray_queue (void)
2449 {
2450         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2451                 sgen_workers_init_distribute_gray_queue ();
2452                 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2453                                 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2454         } else {
2455                 sgen_gray_object_queue_init (&gray_queue, NULL);
2456         }
2457 }
2458
2459 static void
2460 pin_stage_object_callback (char *obj, size_t size, void *data)
2461 {
2462         sgen_pin_stage_ptr (obj);
2463         /* FIXME: do pin stats if enabled */
2464 }
2465
2466 /*
2467  * Collect objects in the nursery.  Returns whether to trigger a major
2468  * collection.
2469  */
2470 static gboolean
2471 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2472 {
2473         gboolean needs_major;
2474         size_t max_garbage_amount;
2475         char *nursery_next;
2476         FinishRememberedSetScanJobData *frssjd;
2477         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2478         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2479         ScanThreadDataJobData *stdjd;
2480         mword fragment_total;
2481         ScanCopyContext ctx;
2482         TV_DECLARE (all_atv);
2483         TV_DECLARE (all_btv);
2484         TV_DECLARE (atv);
2485         TV_DECLARE (btv);
2486
2487         if (disable_minor_collections)
2488                 return TRUE;
2489
2490         MONO_GC_BEGIN (GENERATION_NURSERY);
2491         binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2492
2493         verify_nursery ();
2494
2495 #ifndef DISABLE_PERFCOUNTERS
2496         mono_perfcounters->gc_collections0++;
2497 #endif
2498
2499         current_collection_generation = GENERATION_NURSERY;
2500         if (sgen_collection_is_parallel ())
2501                 current_object_ops = sgen_minor_collector.parallel_ops;
2502         else
2503                 current_object_ops = sgen_minor_collector.serial_ops;
2504
2505         reset_pinned_from_failed_allocation ();
2506
2507         check_scan_starts ();
2508
2509         sgen_nursery_alloc_prepare_for_minor ();
2510
2511         degraded_mode = 0;
2512         objects_pinned = 0;
2513         nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2514         /* FIXME: optimize later to use the higher address where an object can be present */
2515         nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2516
2517         SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", stat_minor_gcs, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
2518         max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2519         g_assert (nursery_section->size >= max_garbage_amount);
2520
2521         /* world must be stopped already */
2522         TV_GETTIME (all_atv);
2523         atv = all_atv;
2524
2525         TV_GETTIME (btv);
2526         time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2527
2528         if (xdomain_checks) {
2529                 sgen_clear_nursery_fragments ();
2530                 check_for_xdomain_refs ();
2531         }
2532
2533         nursery_section->next_data = nursery_next;
2534
2535         major_collector.start_nursery_collection ();
2536
2537         sgen_memgov_minor_collection_start ();
2538
2539         init_gray_queue ();
2540
2541         stat_minor_gcs++;
2542         gc_stats.minor_gc_count ++;
2543
2544         MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2545
2546         sgen_process_fin_stage_entries ();
2547         sgen_process_dislink_stage_entries ();
2548
2549         MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2550
2551         /* pin from pinned handles */
2552         sgen_init_pinning ();
2553         mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2554         pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2555         /* pin cemented objects */
2556         sgen_cement_iterate (pin_stage_object_callback, NULL);
2557         /* identify pinned objects */
2558         sgen_optimize_pin_queue (0);
2559         sgen_pinning_setup_section (nursery_section);
2560         ctx.scan_func = NULL;
2561         ctx.copy_func = NULL;
2562         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2563         sgen_pin_objects_in_section (nursery_section, ctx);
2564         sgen_pinning_trim_queue_to_section (nursery_section);
2565
2566         TV_GETTIME (atv);
2567         time_minor_pinning += TV_ELAPSED (btv, atv);
2568         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2569         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2570
2571         MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2572
2573         if (whole_heap_check_before_collection) {
2574                 sgen_clear_nursery_fragments ();
2575                 sgen_check_whole_heap (finish_up_concurrent_mark);
2576         }
2577         if (consistency_check_at_minor_collection)
2578                 sgen_check_consistency ();
2579
2580         sgen_workers_start_all_workers ();
2581         sgen_workers_start_marking ();
2582
2583         frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2584         frssjd->heap_start = sgen_get_nursery_start ();
2585         frssjd->heap_end = nursery_next;
2586         sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2587
2588         /* we don't have complete write barrier yet, so we scan all the old generation sections */
2589         TV_GETTIME (btv);
2590         time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2591         SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2592
2593         MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2594
2595         if (!sgen_collection_is_parallel ()) {
2596                 ctx.scan_func = current_object_ops.scan_object;
2597                 ctx.copy_func = NULL;
2598                 ctx.queue = &gray_queue;
2599                 sgen_drain_gray_stack (-1, ctx);
2600         }
2601
2602         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2603                 report_registered_roots ();
2604         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2605                 report_finalizer_roots ();
2606         TV_GETTIME (atv);
2607         time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2608
2609         MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2610
2611         /* registered roots, this includes static fields */
2612         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2613         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2614         scrrjd_normal->scan_func = current_object_ops.scan_object;
2615         scrrjd_normal->heap_start = sgen_get_nursery_start ();
2616         scrrjd_normal->heap_end = nursery_next;
2617         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2618         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2619
2620         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2621         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2622         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2623         scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2624         scrrjd_wbarrier->heap_end = nursery_next;
2625         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2626         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2627
2628         TV_GETTIME (btv);
2629         time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2630
2631         MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2632
2633         /* thread data */
2634         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2635         stdjd->heap_start = sgen_get_nursery_start ();
2636         stdjd->heap_end = nursery_next;
2637         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2638
2639         TV_GETTIME (atv);
2640         time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2641         btv = atv;
2642
2643         MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2644
2645         g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2646
2647         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2648                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2649
2650         /* Scan the list of objects ready for finalization. If */
2651         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2652         sfejd_fin_ready->list = fin_ready_list;
2653         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2654
2655         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2656         sfejd_critical_fin->list = critical_fin_list;
2657         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2658
2659         MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2660
2661         finish_gray_stack (sgen_get_nursery_start (), nursery_next, GENERATION_NURSERY, &gray_queue);
2662         TV_GETTIME (atv);
2663         time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2664         mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2665
2666         MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2667
2668         /*
2669          * The (single-threaded) finalization code might have done
2670          * some copying/marking so we can only reset the GC thread's
2671          * worker data here instead of earlier when we joined the
2672          * workers.
2673          */
2674         sgen_workers_reset_data ();
2675
2676         if (objects_pinned) {
2677                 sgen_optimize_pin_queue (0);
2678                 sgen_pinning_setup_section (nursery_section);
2679         }
2680
2681         /* walk the pin_queue, build up the fragment list of free memory, unmark
2682          * pinned objects as we go, memzero() the empty fragments so they are ready for the
2683          * next allocations.
2684          */
2685         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2686         fragment_total = sgen_build_nursery_fragments (nursery_section,
2687                         nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2688                         unpin_queue);
2689         if (!fragment_total)
2690                 degraded_mode = 1;
2691
2692         /* Clear TLABs for all threads */
2693         sgen_clear_tlabs ();
2694
2695         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2696         TV_GETTIME (btv);
2697         time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2698         SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2699
2700         if (consistency_check_at_minor_collection)
2701                 sgen_check_major_refs ();
2702
2703         major_collector.finish_nursery_collection ();
2704
2705         TV_GETTIME (all_btv);
2706         gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2707
2708         if (heap_dump_file)
2709                 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2710
2711         /* prepare the pin queue for the next collection */
2712         sgen_finish_pinning ();
2713         if (fin_ready_list || critical_fin_list) {
2714                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2715                 mono_gc_finalize_notify ();
2716         }
2717         sgen_pin_stats_reset ();
2718         /* clear cemented hash */
2719         sgen_cement_clear_below_threshold ();
2720
2721         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2722
2723         remset.finish_minor_collection ();
2724
2725         check_scan_starts ();
2726
2727         binary_protocol_flush_buffers (FALSE);
2728
2729         sgen_memgov_minor_collection_end ();
2730
2731         /*objects are late pinned because of lack of memory, so a major is a good call*/
2732         needs_major = objects_pinned > 0;
2733         current_collection_generation = -1;
2734         objects_pinned = 0;
2735
2736         MONO_GC_END (GENERATION_NURSERY);
2737         binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2738
2739         if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2740                 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2741
2742         return needs_major;
2743 }
2744
2745 static void
2746 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2747 {
2748         ctx->scan_func (obj, ctx->queue);
2749 }
2750
2751 static void
2752 scan_nursery_objects (ScanCopyContext ctx)
2753 {
2754         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2755                         (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2756 }
2757
2758 static void
2759 major_copy_or_mark_from_roots (int *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2760 {
2761         LOSObject *bigobj;
2762         TV_DECLARE (atv);
2763         TV_DECLARE (btv);
2764         /* FIXME: only use these values for the precise scan
2765          * note that to_space pointers should be excluded anyway...
2766          */
2767         char *heap_start = NULL;
2768         char *heap_end = (char*)-1;
2769         gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2770         GCRootReport root_report = { 0 };
2771         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2772         ScanThreadDataJobData *stdjd;
2773         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2774         ScanCopyContext ctx;
2775
2776         if (concurrent_collection_in_progress) {
2777                 /*This cleans up unused fragments */
2778                 sgen_nursery_allocator_prepare_for_pinning ();
2779
2780                 if (do_concurrent_checks)
2781                         check_nursery_is_clean ();
2782         } else {
2783                 /* The concurrent collector doesn't touch the nursery. */
2784                 sgen_nursery_alloc_prepare_for_major ();
2785         }
2786
2787         init_gray_queue ();
2788
2789         TV_GETTIME (atv);
2790
2791         /* Pinning depends on this */
2792         sgen_clear_nursery_fragments ();
2793
2794         if (whole_heap_check_before_collection)
2795                 sgen_check_whole_heap (finish_up_concurrent_mark);
2796
2797         TV_GETTIME (btv);
2798         time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2799
2800         if (!sgen_collection_is_concurrent ())
2801                 nursery_section->next_data = sgen_get_nursery_end ();
2802         /* we should also coalesce scanning from sections close to each other
2803          * and deal with pointers outside of the sections later.
2804          */
2805
2806         objects_pinned = 0;
2807         *major_collector.have_swept = FALSE;
2808
2809         if (xdomain_checks) {
2810                 sgen_clear_nursery_fragments ();
2811                 check_for_xdomain_refs ();
2812         }
2813
2814         if (!concurrent_collection_in_progress) {
2815                 /* Remsets are not useful for a major collection */
2816                 remset.prepare_for_major_collection ();
2817         }
2818
2819         sgen_process_fin_stage_entries ();
2820         sgen_process_dislink_stage_entries ();
2821
2822         TV_GETTIME (atv);
2823         sgen_init_pinning ();
2824         SGEN_LOG (6, "Collecting pinned addresses");
2825         pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2826
2827         if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2828                 if (major_collector.is_concurrent) {
2829                         /*
2830                          * The concurrent major collector cannot evict
2831                          * yet, so we need to pin cemented objects to
2832                          * not break some asserts.
2833                          *
2834                          * FIXME: We could evict now!
2835                          */
2836                         sgen_cement_iterate (pin_stage_object_callback, NULL);
2837                 }
2838
2839                 if (!concurrent_collection_in_progress)
2840                         sgen_cement_reset ();
2841         }
2842
2843         sgen_optimize_pin_queue (0);
2844
2845         /*
2846          * The concurrent collector doesn't move objects, neither on
2847          * the major heap nor in the nursery, so we can mark even
2848          * before pinning has finished.  For the non-concurrent
2849          * collector we start the workers after pinning.
2850          */
2851         if (concurrent_collection_in_progress) {
2852                 sgen_workers_start_all_workers ();
2853                 sgen_workers_start_marking ();
2854         }
2855
2856         /*
2857          * pin_queue now contains all candidate pointers, sorted and
2858          * uniqued.  We must do two passes now to figure out which
2859          * objects are pinned.
2860          *
2861          * The first is to find within the pin_queue the area for each
2862          * section.  This requires that the pin_queue be sorted.  We
2863          * also process the LOS objects and pinned chunks here.
2864          *
2865          * The second, destructive, pass is to reduce the section
2866          * areas to pointers to the actually pinned objects.
2867          */
2868         SGEN_LOG (6, "Pinning from sections");
2869         /* first pass for the sections */
2870         sgen_find_section_pin_queue_start_end (nursery_section);
2871         major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2872         /* identify possible pointers to the insize of large objects */
2873         SGEN_LOG (6, "Pinning from large objects");
2874         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2875                 int dummy;
2876                 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2877                         binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2878
2879 #ifdef ENABLE_DTRACE
2880                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2881                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2882                                 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2883                         }
2884 #endif
2885
2886                         if (sgen_los_object_is_pinned (bigobj->data)) {
2887                                 g_assert (finish_up_concurrent_mark);
2888                                 continue;
2889                         }
2890                         sgen_los_pin_object (bigobj->data);
2891                         /* FIXME: only enqueue if object has references */
2892                         GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2893                         if (G_UNLIKELY (do_pin_stats))
2894                                 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2895                         SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data, safe_name (bigobj->data), (unsigned long)sgen_los_object_size (bigobj));
2896
2897                         if (profile_roots)
2898                                 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2899                 }
2900         }
2901         if (profile_roots)
2902                 notify_gc_roots (&root_report);
2903         /* second pass for the sections */
2904         ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2905         ctx.copy_func = NULL;
2906         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2907
2908         /*
2909          * Concurrent mark never follows references into the nursery.
2910          * In the start and finish pauses we must scan live nursery
2911          * objects, though.  We could simply scan all nursery objects,
2912          * but that would be conservative.  The easiest way is to do a
2913          * nursery collection, which copies all live nursery objects
2914          * (except pinned ones, with the simple nursery) to the major
2915          * heap.  Scanning the mod union table later will then scan
2916          * those promoted objects, provided they're reachable.  Pinned
2917          * objects in the nursery - which we can trivially find in the
2918          * pinning queue - are treated as roots in the mark pauses.
2919          *
2920          * The split nursery complicates the latter part because
2921          * non-pinned objects can survive in the nursery.  That's why
2922          * we need to do a full front-to-back scan of the nursery,
2923          * marking all objects.
2924          *
2925          * Non-concurrent mark evacuates from the nursery, so it's
2926          * sufficient to just scan pinned nursery objects.
2927          */
2928         if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2929                 scan_nursery_objects (ctx);
2930         } else {
2931                 sgen_pin_objects_in_section (nursery_section, ctx);
2932                 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2933                         sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2934         }
2935
2936         major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2937         if (old_next_pin_slot)
2938                 *old_next_pin_slot = sgen_get_pinned_count ();
2939
2940         TV_GETTIME (btv);
2941         time_major_pinning += TV_ELAPSED (atv, btv);
2942         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2943         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2944
2945         major_collector.init_to_space ();
2946
2947 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2948         main_gc_thread = mono_native_thread_self ();
2949 #endif
2950
2951         if (!concurrent_collection_in_progress && major_collector.is_parallel) {
2952                 sgen_workers_start_all_workers ();
2953                 sgen_workers_start_marking ();
2954         }
2955
2956         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2957                 report_registered_roots ();
2958         TV_GETTIME (atv);
2959         time_major_scan_pinned += TV_ELAPSED (btv, atv);
2960
2961         /* registered roots, this includes static fields */
2962         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2963         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2964         scrrjd_normal->scan_func = current_object_ops.scan_object;
2965         scrrjd_normal->heap_start = heap_start;
2966         scrrjd_normal->heap_end = heap_end;
2967         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2968         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2969
2970         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2971         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2972         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2973         scrrjd_wbarrier->heap_start = heap_start;
2974         scrrjd_wbarrier->heap_end = heap_end;
2975         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2976         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2977
2978         TV_GETTIME (btv);
2979         time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2980
2981         /* Threads */
2982         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2983         stdjd->heap_start = heap_start;
2984         stdjd->heap_end = heap_end;
2985         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2986
2987         TV_GETTIME (atv);
2988         time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2989
2990         TV_GETTIME (btv);
2991         time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2992
2993         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2994                 report_finalizer_roots ();
2995
2996         /* scan the list of objects ready for finalization */
2997         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2998         sfejd_fin_ready->list = fin_ready_list;
2999         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
3000
3001         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3002         sfejd_critical_fin->list = critical_fin_list;
3003         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
3004
3005         if (scan_mod_union) {
3006                 g_assert (finish_up_concurrent_mark);
3007
3008                 /* Mod union card table */
3009                 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
3010                 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
3011         }
3012
3013         TV_GETTIME (atv);
3014         time_major_scan_finalized += TV_ELAPSED (btv, atv);
3015         SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
3016
3017         TV_GETTIME (btv);
3018         time_major_scan_big_objects += TV_ELAPSED (atv, btv);
3019
3020         if (concurrent_collection_in_progress) {
3021                 /* prepare the pin queue for the next collection */
3022                 sgen_finish_pinning ();
3023
3024                 sgen_pin_stats_reset ();
3025
3026                 if (do_concurrent_checks)
3027                         check_nursery_is_clean ();
3028         }
3029 }
3030
3031 static void
3032 major_start_collection (gboolean concurrent, int *old_next_pin_slot)
3033 {
3034         MONO_GC_BEGIN (GENERATION_OLD);
3035         binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
3036
3037         current_collection_generation = GENERATION_OLD;
3038 #ifndef DISABLE_PERFCOUNTERS
3039         mono_perfcounters->gc_collections1++;
3040 #endif
3041
3042         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3043
3044         if (concurrent) {
3045                 g_assert (major_collector.is_concurrent);
3046                 concurrent_collection_in_progress = TRUE;
3047
3048                 sgen_cement_concurrent_start ();
3049
3050                 current_object_ops = major_collector.major_concurrent_ops;
3051         } else {
3052                 current_object_ops = major_collector.major_ops;
3053         }
3054
3055         reset_pinned_from_failed_allocation ();
3056
3057         sgen_memgov_major_collection_start ();
3058
3059         //count_ref_nonref_objs ();
3060         //consistency_check ();
3061
3062         check_scan_starts ();
3063
3064         degraded_mode = 0;
3065         SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
3066         stat_major_gcs++;
3067         gc_stats.major_gc_count ++;
3068
3069         if (major_collector.start_major_collection)
3070                 major_collector.start_major_collection ();
3071
3072         major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
3073 }
3074
3075 static void
3076 wait_for_workers_to_finish (void)
3077 {
3078         if (concurrent_collection_in_progress || major_collector.is_parallel) {
3079                 gray_queue_redirect (&gray_queue);
3080                 sgen_workers_join ();
3081         }
3082
3083         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3084
3085 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3086         main_gc_thread = NULL;
3087 #endif
3088 }
3089
3090 static void
3091 major_finish_collection (const char *reason, int old_next_pin_slot, gboolean scan_mod_union)
3092 {
3093         LOSObject *bigobj, *prevbo;
3094         TV_DECLARE (atv);
3095         TV_DECLARE (btv);
3096         char *heap_start = NULL;
3097         char *heap_end = (char*)-1;
3098
3099         TV_GETTIME (btv);
3100
3101         if (concurrent_collection_in_progress || major_collector.is_parallel)
3102                 wait_for_workers_to_finish ();
3103
3104         if (concurrent_collection_in_progress) {
3105                 current_object_ops = major_collector.major_concurrent_ops;
3106
3107                 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
3108                 wait_for_workers_to_finish ();
3109
3110                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3111
3112                 if (do_concurrent_checks)
3113                         check_nursery_is_clean ();
3114         } else {
3115                 current_object_ops = major_collector.major_ops;
3116         }
3117
3118         /*
3119          * The workers have stopped so we need to finish gray queue
3120          * work that might result from finalization in the main GC
3121          * thread.  Redirection must therefore be turned off.
3122          */
3123         sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
3124         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3125
3126         /* all the objects in the heap */
3127         finish_gray_stack (heap_start, heap_end, GENERATION_OLD, &gray_queue);
3128         TV_GETTIME (atv);
3129         time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3130
3131         /*
3132          * The (single-threaded) finalization code might have done
3133          * some copying/marking so we can only reset the GC thread's
3134          * worker data here instead of earlier when we joined the
3135          * workers.
3136          */
3137         sgen_workers_reset_data ();
3138
3139         if (objects_pinned) {
3140                 g_assert (!concurrent_collection_in_progress);
3141
3142                 /*This is slow, but we just OOM'd*/
3143                 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3144                 sgen_optimize_pin_queue (0);
3145                 sgen_find_section_pin_queue_start_end (nursery_section);
3146                 objects_pinned = 0;
3147         }
3148
3149         reset_heap_boundaries ();
3150         sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3151
3152         if (check_mark_bits_after_major_collection)
3153                 sgen_check_major_heap_marked ();
3154
3155         MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
3156
3157         /* sweep the big objects list */
3158         prevbo = NULL;
3159         for (bigobj = los_object_list; bigobj;) {
3160                 g_assert (!object_is_pinned (bigobj->data));
3161                 if (sgen_los_object_is_pinned (bigobj->data)) {
3162                         sgen_los_unpin_object (bigobj->data);
3163                         sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
3164                 } else {
3165                         LOSObject *to_free;
3166                         /* not referenced anywhere, so we can free it */
3167                         if (prevbo)
3168                                 prevbo->next = bigobj->next;
3169                         else
3170                                 los_object_list = bigobj->next;
3171                         to_free = bigobj;
3172                         bigobj = bigobj->next;
3173                         sgen_los_free_object (to_free);
3174                         continue;
3175                 }
3176                 prevbo = bigobj;
3177                 bigobj = bigobj->next;
3178         }
3179
3180         TV_GETTIME (btv);
3181         time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3182
3183         sgen_los_sweep ();
3184
3185         TV_GETTIME (atv);
3186         time_major_los_sweep += TV_ELAPSED (btv, atv);
3187
3188         major_collector.sweep ();
3189
3190         MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
3191
3192         TV_GETTIME (btv);
3193         time_major_sweep += TV_ELAPSED (atv, btv);
3194
3195         if (!concurrent_collection_in_progress) {
3196                 /* walk the pin_queue, build up the fragment list of free memory, unmark
3197                  * pinned objects as we go, memzero() the empty fragments so they are ready for the
3198                  * next allocations.
3199                  */
3200                 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
3201                         degraded_mode = 1;
3202
3203                 /* prepare the pin queue for the next collection */
3204                 sgen_finish_pinning ();
3205
3206                 /* Clear TLABs for all threads */
3207                 sgen_clear_tlabs ();
3208
3209                 sgen_pin_stats_reset ();
3210         }
3211
3212         if (concurrent_collection_in_progress)
3213                 sgen_cement_concurrent_finish ();
3214         sgen_cement_clear_below_threshold ();
3215
3216         TV_GETTIME (atv);
3217         time_major_fragment_creation += TV_ELAPSED (btv, atv);
3218
3219         if (heap_dump_file)
3220                 dump_heap ("major", stat_major_gcs - 1, reason);
3221
3222         if (fin_ready_list || critical_fin_list) {
3223                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
3224                 mono_gc_finalize_notify ();
3225         }
3226
3227         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3228
3229         sgen_memgov_major_collection_end ();
3230         current_collection_generation = -1;
3231
3232         major_collector.finish_major_collection ();
3233
3234         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3235
3236         if (concurrent_collection_in_progress)
3237                 concurrent_collection_in_progress = FALSE;
3238
3239         check_scan_starts ();
3240
3241         binary_protocol_flush_buffers (FALSE);
3242
3243         //consistency_check ();
3244
3245         MONO_GC_END (GENERATION_OLD);
3246         binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
3247 }
3248
3249 static gboolean
3250 major_do_collection (const char *reason)
3251 {
3252         TV_DECLARE (all_atv);
3253         TV_DECLARE (all_btv);
3254         int old_next_pin_slot;
3255
3256         if (major_collector.get_and_reset_num_major_objects_marked) {
3257                 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3258                 g_assert (!num_marked);
3259         }
3260
3261         /* world must be stopped already */
3262         TV_GETTIME (all_atv);
3263
3264         major_start_collection (FALSE, &old_next_pin_slot);
3265         major_finish_collection (reason, old_next_pin_slot, FALSE);
3266
3267         TV_GETTIME (all_btv);
3268         gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3269
3270         /* FIXME: also report this to the user, preferably in gc-end. */
3271         if (major_collector.get_and_reset_num_major_objects_marked)
3272                 major_collector.get_and_reset_num_major_objects_marked ();
3273
3274         return bytes_pinned_from_failed_allocation > 0;
3275 }
3276
3277 static gboolean major_do_collection (const char *reason);
3278
3279 static void
3280 major_start_concurrent_collection (const char *reason)
3281 {
3282         long long num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3283
3284         g_assert (num_objects_marked == 0);
3285
3286         MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3287
3288         // FIXME: store reason and pass it when finishing
3289         major_start_collection (TRUE, NULL);
3290
3291         gray_queue_redirect (&gray_queue);
3292         sgen_workers_wait_for_jobs ();
3293
3294         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3295         MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3296
3297         current_collection_generation = -1;
3298 }
3299
3300 static gboolean
3301 major_update_or_finish_concurrent_collection (gboolean force_finish)
3302 {
3303         SgenGrayQueue unpin_queue;
3304         memset (&unpin_queue, 0, sizeof (unpin_queue));
3305
3306         MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3307
3308         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3309
3310         major_collector.update_cardtable_mod_union ();
3311         sgen_los_update_cardtable_mod_union ();
3312
3313         if (!force_finish && !sgen_workers_all_done ()) {
3314                 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3315                 return FALSE;
3316         }
3317
3318         collect_nursery (&unpin_queue, TRUE);
3319
3320         current_collection_generation = GENERATION_OLD;
3321         major_finish_collection ("finishing", -1, TRUE);
3322
3323         if (whole_heap_check_before_collection)
3324                 sgen_check_whole_heap (FALSE);
3325
3326         unpin_objects_from_queue (&unpin_queue);
3327         sgen_gray_object_queue_deinit (&unpin_queue);
3328
3329         MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3330
3331         current_collection_generation = -1;
3332
3333         return TRUE;
3334 }
3335
3336 /*
3337  * Ensure an allocation request for @size will succeed by freeing enough memory.
3338  *
3339  * LOCKING: The GC lock MUST be held.
3340  */
3341 void
3342 sgen_ensure_free_space (size_t size)
3343 {
3344         int generation_to_collect = -1;
3345         const char *reason = NULL;
3346
3347
3348         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3349                 if (sgen_need_major_collection (size)) {
3350                         reason = "LOS overflow";
3351                         generation_to_collect = GENERATION_OLD;
3352                 }
3353         } else {
3354                 if (degraded_mode) {
3355                         if (sgen_need_major_collection (size)) {
3356                                 reason = "Degraded mode overflow";
3357                                 generation_to_collect = GENERATION_OLD;
3358                         }
3359                 } else if (sgen_need_major_collection (size)) {
3360                         reason = "Minor allowance";
3361                         generation_to_collect = GENERATION_OLD;
3362                 } else {
3363                         generation_to_collect = GENERATION_NURSERY;
3364                         reason = "Nursery full";
3365                 }
3366         }
3367
3368         if (generation_to_collect == -1) {
3369                 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3370                         generation_to_collect = GENERATION_OLD;
3371                         reason = "Finish concurrent collection";
3372                 }
3373         }
3374
3375         if (generation_to_collect == -1)
3376                 return;
3377         sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3378 }
3379
3380 void
3381 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3382 {
3383         TV_DECLARE (gc_end);
3384         GGTimingInfo infos [2];
3385         int overflow_generation_to_collect = -1;
3386         int oldest_generation_collected = generation_to_collect;
3387         const char *overflow_reason = NULL;
3388
3389         MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3390
3391         g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3392
3393         memset (infos, 0, sizeof (infos));
3394         mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3395
3396         infos [0].generation = generation_to_collect;
3397         infos [0].reason = reason;
3398         infos [0].is_overflow = FALSE;
3399         TV_GETTIME (infos [0].total_time);
3400         infos [1].generation = -1;
3401
3402         sgen_stop_world (generation_to_collect);
3403
3404         if (concurrent_collection_in_progress) {
3405                 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3406                         oldest_generation_collected = GENERATION_OLD;
3407                         goto done;
3408                 }
3409                 if (generation_to_collect == GENERATION_OLD)
3410                         goto done;
3411         } else {
3412                 if (generation_to_collect == GENERATION_OLD &&
3413                                 allow_synchronous_major &&
3414                                 major_collector.want_synchronous_collection &&
3415                                 *major_collector.want_synchronous_collection) {
3416                         wait_to_finish = TRUE;
3417                 }
3418         }
3419
3420         //FIXME extract overflow reason
3421         if (generation_to_collect == GENERATION_NURSERY) {
3422                 if (collect_nursery (NULL, FALSE)) {
3423                         overflow_generation_to_collect = GENERATION_OLD;
3424                         overflow_reason = "Minor overflow";
3425                 }
3426         } else {
3427                 if (major_collector.is_concurrent) {
3428                         g_assert (!concurrent_collection_in_progress);
3429                         if (!wait_to_finish)
3430                                 collect_nursery (NULL, FALSE);
3431                 }
3432
3433                 if (major_collector.is_concurrent && !wait_to_finish) {
3434                         major_start_concurrent_collection (reason);
3435                         // FIXME: set infos[0] properly
3436                         goto done;
3437                 } else {
3438                         if (major_do_collection (reason)) {
3439                                 overflow_generation_to_collect = GENERATION_NURSERY;
3440                                 overflow_reason = "Excessive pinning";
3441                         }
3442                 }
3443         }
3444
3445         TV_GETTIME (gc_end);
3446         infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3447
3448
3449         if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3450                 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3451                 infos [1].generation = overflow_generation_to_collect;
3452                 infos [1].reason = overflow_reason;
3453                 infos [1].is_overflow = TRUE;
3454                 infos [1].total_time = gc_end;
3455
3456                 if (overflow_generation_to_collect == GENERATION_NURSERY)
3457                         collect_nursery (NULL, FALSE);
3458                 else
3459                         major_do_collection (overflow_reason);
3460
3461                 TV_GETTIME (gc_end);
3462                 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3463
3464                 /* keep events symmetric */
3465                 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3466
3467                 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3468         }
3469
3470         SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3471
3472         /* this also sets the proper pointers for the next allocation */
3473         if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3474                 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3475                 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3476                 sgen_dump_pin_queue ();
3477                 degraded_mode = 1;
3478         }
3479
3480  done:
3481         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3482
3483         sgen_restart_world (oldest_generation_collected, infos);
3484
3485         mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3486 }
3487
3488 /*
3489  * ######################################################################
3490  * ########  Memory allocation from the OS
3491  * ######################################################################
3492  * This section of code deals with getting memory from the OS and
3493  * allocating memory for GC-internal data structures.
3494  * Internal memory can be handled with a freelist for small objects.
3495  */
3496
3497 /*
3498  * Debug reporting.
3499  */
3500 G_GNUC_UNUSED static void
3501 report_internal_mem_usage (void)
3502 {
3503         printf ("Internal memory usage:\n");
3504         sgen_report_internal_mem_usage ();
3505         printf ("Pinned memory usage:\n");
3506         major_collector.report_pinned_memory_usage ();
3507 }
3508
3509 /*
3510  * ######################################################################
3511  * ########  Finalization support
3512  * ######################################################################
3513  */
3514
3515 static inline gboolean
3516 sgen_major_is_object_alive (void *object)
3517 {
3518         mword objsize;
3519
3520         /* Oldgen objects can be pinned and forwarded too */
3521         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3522                 return TRUE;
3523
3524         /*
3525          * FIXME: major_collector.is_object_live() also calculates the
3526          * size.  Avoid the double calculation.
3527          */
3528         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3529         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3530                 return sgen_los_object_is_pinned (object);
3531
3532         return major_collector.is_object_live (object);
3533 }
3534
3535 /*
3536  * If the object has been forwarded it means it's still referenced from a root.
3537  * If it is pinned it's still alive as well.
3538  * A LOS object is only alive if we have pinned it.
3539  * Return TRUE if @obj is ready to be finalized.
3540  */
3541 static inline gboolean
3542 sgen_is_object_alive (void *object)
3543 {
3544         if (ptr_in_nursery (object))
3545                 return sgen_nursery_is_object_alive (object);
3546
3547         return sgen_major_is_object_alive (object);
3548 }
3549
3550 /*
3551  * This function returns true if @object is either alive or it belongs to the old gen
3552  * and we're currently doing a minor collection.
3553  */
3554 static inline int
3555 sgen_is_object_alive_for_current_gen (char *object)
3556 {
3557         if (ptr_in_nursery (object))
3558                 return sgen_nursery_is_object_alive (object);
3559
3560         if (current_collection_generation == GENERATION_NURSERY)
3561                 return TRUE;
3562
3563         return sgen_major_is_object_alive (object);
3564 }
3565
3566 /*
3567  * This function returns true if @object is either alive and belongs to the
3568  * current collection - major collections are full heap, so old gen objects
3569  * are never alive during a minor collection.
3570  */
3571 static inline int
3572 sgen_is_object_alive_and_on_current_collection (char *object)
3573 {
3574         if (ptr_in_nursery (object))
3575                 return sgen_nursery_is_object_alive (object);
3576
3577         if (current_collection_generation == GENERATION_NURSERY)
3578                 return FALSE;
3579
3580         return sgen_major_is_object_alive (object);
3581 }
3582
3583
3584 gboolean
3585 sgen_gc_is_object_ready_for_finalization (void *object)
3586 {
3587         return !sgen_is_object_alive (object);
3588 }
3589
3590 static gboolean
3591 has_critical_finalizer (MonoObject *obj)
3592 {
3593         MonoClass *class;
3594
3595         if (!mono_defaults.critical_finalizer_object)
3596                 return FALSE;
3597
3598         class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3599
3600         return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3601 }
3602
3603 void
3604 sgen_queue_finalization_entry (MonoObject *obj)
3605 {
3606         FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3607         gboolean critical = has_critical_finalizer (obj);
3608         entry->object = obj;
3609         if (critical) {
3610                 entry->next = critical_fin_list;
3611                 critical_fin_list = entry;
3612         } else {
3613                 entry->next = fin_ready_list;
3614                 fin_ready_list = entry;
3615         }
3616
3617 #ifdef ENABLE_DTRACE
3618         if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3619                 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3620                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3621                 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3622                                 vt->klass->name_space, vt->klass->name, gen, critical);
3623         }
3624 #endif
3625 }
3626
3627 gboolean
3628 sgen_object_is_live (void *obj)
3629 {
3630         return sgen_is_object_alive_and_on_current_collection (obj);
3631 }
3632
3633 /* LOCKING: requires that the GC lock is held */
3634 static void
3635 null_ephemerons_for_domain (MonoDomain *domain)
3636 {
3637         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3638
3639         while (current) {
3640                 MonoObject *object = (MonoObject*)current->array;
3641
3642                 if (object && !object->vtable) {
3643                         EphemeronLinkNode *tmp = current;
3644
3645                         if (prev)
3646                                 prev->next = current->next;
3647                         else
3648                                 ephemeron_list = current->next;
3649
3650                         current = current->next;
3651                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3652                 } else {
3653                         prev = current;
3654                         current = current->next;
3655                 }
3656         }
3657 }
3658
3659 /* LOCKING: requires that the GC lock is held */
3660 static void
3661 clear_unreachable_ephemerons (ScanCopyContext ctx)
3662 {
3663         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3664         GrayQueue *queue = ctx.queue;
3665         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3666         MonoArray *array;
3667         Ephemeron *cur, *array_end;
3668         char *tombstone;
3669
3670         while (current) {
3671                 char *object = current->array;
3672
3673                 if (!sgen_is_object_alive_for_current_gen (object)) {
3674                         EphemeronLinkNode *tmp = current;
3675
3676                         SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3677
3678                         if (prev)
3679                                 prev->next = current->next;
3680                         else
3681                                 ephemeron_list = current->next;
3682
3683                         current = current->next;
3684                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3685
3686                         continue;
3687                 }
3688
3689                 copy_func ((void**)&object, queue);
3690                 current->array = object;
3691
3692                 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3693
3694                 array = (MonoArray*)object;
3695                 cur = mono_array_addr (array, Ephemeron, 0);
3696                 array_end = cur + mono_array_length_fast (array);
3697                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3698
3699                 for (; cur < array_end; ++cur) {
3700                         char *key = (char*)cur->key;
3701
3702                         if (!key || key == tombstone)
3703                                 continue;
3704
3705                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3706                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3707                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3708
3709                         if (!sgen_is_object_alive_for_current_gen (key)) {
3710                                 cur->key = tombstone;
3711                                 cur->value = NULL;
3712                                 continue;
3713                         }
3714                 }
3715                 prev = current;
3716                 current = current->next;
3717         }
3718 }
3719
3720 /*
3721 LOCKING: requires that the GC lock is held
3722
3723 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3724 */
3725 static int
3726 mark_ephemerons_in_range (ScanCopyContext ctx)
3727 {
3728         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3729         GrayQueue *queue = ctx.queue;
3730         int nothing_marked = 1;
3731         EphemeronLinkNode *current = ephemeron_list;
3732         MonoArray *array;
3733         Ephemeron *cur, *array_end;
3734         char *tombstone;
3735
3736         for (current = ephemeron_list; current; current = current->next) {
3737                 char *object = current->array;
3738                 SGEN_LOG (5, "Ephemeron array at %p", object);
3739
3740                 /*It has to be alive*/
3741                 if (!sgen_is_object_alive_for_current_gen (object)) {
3742                         SGEN_LOG (5, "\tnot reachable");
3743                         continue;
3744                 }
3745
3746                 copy_func ((void**)&object, queue);
3747
3748                 array = (MonoArray*)object;
3749                 cur = mono_array_addr (array, Ephemeron, 0);
3750                 array_end = cur + mono_array_length_fast (array);
3751                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3752
3753                 for (; cur < array_end; ++cur) {
3754                         char *key = cur->key;
3755
3756                         if (!key || key == tombstone)
3757                                 continue;
3758
3759                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3760                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3761                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3762
3763                         if (sgen_is_object_alive_for_current_gen (key)) {
3764                                 char *value = cur->value;
3765
3766                                 copy_func ((void**)&cur->key, queue);
3767                                 if (value) {
3768                                         if (!sgen_is_object_alive_for_current_gen (value))
3769                                                 nothing_marked = 0;
3770                                         copy_func ((void**)&cur->value, queue);
3771                                 }
3772                         }
3773                 }
3774         }
3775
3776         SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3777         return nothing_marked;
3778 }
3779
3780 int
3781 mono_gc_invoke_finalizers (void)
3782 {
3783         FinalizeReadyEntry *entry = NULL;
3784         gboolean entry_is_critical = FALSE;
3785         int count = 0;
3786         void *obj;
3787         /* FIXME: batch to reduce lock contention */
3788         while (fin_ready_list || critical_fin_list) {
3789                 LOCK_GC;
3790
3791                 if (entry) {
3792                         FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3793
3794                         /* We have finalized entry in the last
3795                            interation, now we need to remove it from
3796                            the list. */
3797                         if (*list == entry)
3798                                 *list = entry->next;
3799                         else {
3800                                 FinalizeReadyEntry *e = *list;
3801                                 while (e->next != entry)
3802                                         e = e->next;
3803                                 e->next = entry->next;
3804                         }
3805                         sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3806                         entry = NULL;
3807                 }
3808
3809                 /* Now look for the first non-null entry. */
3810                 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3811                         ;
3812                 if (entry) {
3813                         entry_is_critical = FALSE;
3814                 } else {
3815                         entry_is_critical = TRUE;
3816                         for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3817                                 ;
3818                 }
3819
3820                 if (entry) {
3821                         g_assert (entry->object);
3822                         num_ready_finalizers--;
3823                         obj = entry->object;
3824                         entry->object = NULL;
3825                         SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3826                 }
3827
3828                 UNLOCK_GC;
3829
3830                 if (!entry)
3831                         break;
3832
3833                 g_assert (entry->object == NULL);
3834                 count++;
3835                 /* the object is on the stack so it is pinned */
3836                 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3837                 mono_gc_run_finalize (obj, NULL);
3838         }
3839         g_assert (!entry);
3840         return count;
3841 }
3842
3843 gboolean
3844 mono_gc_pending_finalizers (void)
3845 {
3846         return fin_ready_list || critical_fin_list;
3847 }
3848
3849 /*
3850  * ######################################################################
3851  * ########  registered roots support
3852  * ######################################################################
3853  */
3854
3855 /*
3856  * We do not coalesce roots.
3857  */
3858 static int
3859 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3860 {
3861         RootRecord new_root;
3862         int i;
3863         LOCK_GC;
3864         for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3865                 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3866                 /* we allow changing the size and the descriptor (for thread statics etc) */
3867                 if (root) {
3868                         size_t old_size = root->end_root - start;
3869                         root->end_root = start + size;
3870                         g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3871                                           ((root->root_desc == 0) && (descr == NULL)));
3872                         root->root_desc = (mword)descr;
3873                         roots_size += size;
3874                         roots_size -= old_size;
3875                         UNLOCK_GC;
3876                         return TRUE;
3877                 }
3878         }
3879
3880         new_root.end_root = start + size;
3881         new_root.root_desc = (mword)descr;
3882
3883         sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3884         roots_size += size;
3885
3886         SGEN_LOG (3, "Added root for range: %p-%p, descr: %p  (%d/%d bytes)", start, new_root.end_root, descr, (int)size, (int)roots_size);
3887
3888         UNLOCK_GC;
3889         return TRUE;
3890 }
3891
3892 int
3893 mono_gc_register_root (char *start, size_t size, void *descr)
3894 {
3895         return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3896 }
3897
3898 int
3899 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3900 {
3901         return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3902 }
3903
3904 void
3905 mono_gc_deregister_root (char* addr)
3906 {
3907         int root_type;
3908         RootRecord root;
3909
3910         LOCK_GC;
3911         for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3912                 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3913                         roots_size -= (root.end_root - addr);
3914         }
3915         UNLOCK_GC;
3916 }
3917
3918 /*
3919  * ######################################################################
3920  * ########  Thread handling (stop/start code)
3921  * ######################################################################
3922  */
3923
3924 unsigned int sgen_global_stop_count = 0;
3925
3926 int
3927 sgen_get_current_collection_generation (void)
3928 {
3929         return current_collection_generation;
3930 }
3931
3932 void
3933 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3934 {
3935         gc_callbacks = *callbacks;
3936 }
3937
3938 MonoGCCallbacks *
3939 mono_gc_get_gc_callbacks ()
3940 {
3941         return &gc_callbacks;
3942 }
3943
3944 /* Variables holding start/end nursery so it won't have to be passed at every call */
3945 static void *scan_area_arg_start, *scan_area_arg_end;
3946
3947 void
3948 mono_gc_conservatively_scan_area (void *start, void *end)
3949 {
3950         conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3951 }
3952
3953 void*
3954 mono_gc_scan_object (void *obj)
3955 {
3956         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3957         current_object_ops.copy_or_mark_object (&obj, data->queue);
3958         return obj;
3959 }
3960
3961 /*
3962  * Mark from thread stacks and registers.
3963  */
3964 static void
3965 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3966 {
3967         SgenThreadInfo *info;
3968
3969         scan_area_arg_start = start_nursery;
3970         scan_area_arg_end = end_nursery;
3971
3972         FOREACH_THREAD (info) {
3973                 if (info->skip) {
3974                         SGEN_LOG (3, "Skipping dead thread %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3975                         continue;
3976                 }
3977                 if (info->gc_disabled) {
3978                         SGEN_LOG (3, "GC disabled for thread %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3979                         continue;
3980                 }
3981
3982                 if (!info->joined_stw) {
3983                         SGEN_LOG (3, "Skipping thread not seen in STW %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3984                         continue;
3985                 }
3986
3987                 SGEN_LOG (3, "Scanning thread %p, range: %p-%p, size: %td, pinned=%d", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, sgen_get_pinned_count ());
3988                 if (!info->thread_is_dying) {
3989                         if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3990                                 UserCopyOrMarkData data = { NULL, queue };
3991                                 set_user_copy_or_mark_data (&data);
3992                                 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
3993                                 set_user_copy_or_mark_data (NULL);
3994                         } else if (!precise) {
3995                                 if (!conservative_stack_mark) {
3996                                         fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3997                                         conservative_stack_mark = TRUE;
3998                                 }
3999                                 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
4000                         }
4001                 }
4002
4003                 if (!info->thread_is_dying && !precise) {
4004 #ifdef USE_MONO_CTX
4005                         conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
4006                                 start_nursery, end_nursery, PIN_TYPE_STACK);
4007 #else
4008                         conservatively_pin_objects_from (&info->regs, &info->regs + ARCH_NUM_REGS,
4009                                         start_nursery, end_nursery, PIN_TYPE_STACK);
4010 #endif
4011                 }
4012         } END_FOREACH_THREAD
4013 }
4014
4015 static gboolean
4016 ptr_on_stack (void *ptr)
4017 {
4018         gpointer stack_start = &stack_start;
4019         SgenThreadInfo *info = mono_thread_info_current ();
4020
4021         if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
4022                 return TRUE;
4023         return FALSE;
4024 }
4025
4026 static void*
4027 sgen_thread_register (SgenThreadInfo* info, void *addr)
4028 {
4029         LOCK_GC;
4030 #ifndef HAVE_KW_THREAD
4031         info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
4032
4033         g_assert (!mono_native_tls_get_value (thread_info_key));
4034         mono_native_tls_set_value (thread_info_key, info);
4035 #else
4036         sgen_thread_info = info;
4037 #endif
4038
4039 #if !defined(__MACH__)
4040         info->stop_count = -1;
4041         info->signal = 0;
4042 #endif
4043         info->skip = 0;
4044         info->joined_stw = FALSE;
4045         info->doing_handshake = FALSE;
4046         info->thread_is_dying = FALSE;
4047         info->stack_start = NULL;
4048         info->stopped_ip = NULL;
4049         info->stopped_domain = NULL;
4050 #ifdef USE_MONO_CTX
4051         memset (&info->ctx, 0, sizeof (MonoContext));
4052 #else
4053         memset (&info->regs, 0, sizeof (info->regs));
4054 #endif
4055
4056         sgen_init_tlab_info (info);
4057
4058         binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4059
4060         /* try to get it with attributes first */
4061 #if (defined(HAVE_PTHREAD_GETATTR_NP) || defined(HAVE_PTHREAD_ATTR_GET_NP)) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4062   {
4063      size_t size;
4064      void *sstart;
4065      pthread_attr_t attr;
4066
4067 #if defined(HAVE_PTHREAD_GETATTR_NP)
4068     /* Linux */
4069     pthread_getattr_np (pthread_self (), &attr);
4070 #elif defined(HAVE_PTHREAD_ATTR_GET_NP)
4071     /* BSD */
4072     pthread_attr_init (&attr);
4073     pthread_attr_get_np (pthread_self (), &attr);
4074 #else
4075 #error Cannot determine which API is needed to retrieve pthread attributes.
4076 #endif
4077
4078      pthread_attr_getstack (&attr, &sstart, &size);
4079      info->stack_start_limit = sstart;
4080      info->stack_end = (char*)sstart + size;
4081      pthread_attr_destroy (&attr);
4082   }
4083 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4084                  info->stack_end = (char*)pthread_get_stackaddr_np (pthread_self ());
4085                  info->stack_start_limit = (char*)info->stack_end - pthread_get_stacksize_np (pthread_self ());
4086 #else
4087         {
4088                 /* FIXME: we assume the stack grows down */
4089                 gsize stack_bottom = (gsize)addr;
4090                 stack_bottom += 4095;
4091                 stack_bottom &= ~4095;
4092                 info->stack_end = (char*)stack_bottom;
4093         }
4094 #endif
4095
4096 #ifdef HAVE_KW_THREAD
4097         stack_end = info->stack_end;
4098 #endif
4099
4100         SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
4101
4102         if (gc_callbacks.thread_attach_func)
4103                 info->runtime_data = gc_callbacks.thread_attach_func ();
4104
4105         UNLOCK_GC;
4106         return info;
4107 }
4108
4109 static void
4110 sgen_thread_unregister (SgenThreadInfo *p)
4111 {
4112         /* If a delegate is passed to native code and invoked on a thread we dont
4113          * know about, the jit will register it with mono_jit_thread_attach, but
4114          * we have no way of knowing when that thread goes away.  SGen has a TSD
4115          * so we assume that if the domain is still registered, we can detach
4116          * the thread
4117          */
4118         if (mono_domain_get ())
4119                 mono_thread_detach (mono_thread_current ());
4120
4121         p->thread_is_dying = TRUE;
4122
4123         /*
4124         There is a race condition between a thread finishing executing and been removed
4125         from the GC thread set.
4126         This happens on posix systems when TLS data is been cleaned-up, libpthread will
4127         set the thread_info slot to NULL before calling the cleanup function. This
4128         opens a window in which the thread is registered but has a NULL TLS.
4129
4130         The suspend signal handler needs TLS data to know where to store thread state
4131         data or otherwise it will simply ignore the thread.
4132
4133         This solution works because the thread doing STW will wait until all threads been
4134         suspended handshake back, so there is no race between the doing_hankshake test
4135         and the suspend_thread call.
4136
4137         This is not required on systems that do synchronous STW as those can deal with
4138         the above race at suspend time.
4139
4140         FIXME: I believe we could avoid this by using mono_thread_info_lookup when
4141         mono_thread_info_current returns NULL. Or fix mono_thread_info_lookup to do so.
4142         */
4143 #if (defined(__MACH__) && MONO_MACH_ARCH_SUPPORTED) || !defined(HAVE_PTHREAD_KILL)
4144         LOCK_GC;
4145 #else
4146         while (!TRYLOCK_GC) {
4147                 if (!sgen_park_current_thread_if_doing_handshake (p))
4148                         g_usleep (50);
4149         }
4150         MONO_GC_LOCKED ();
4151 #endif
4152
4153         binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4154         SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)mono_thread_info_get_tid (p));
4155
4156         if (gc_callbacks.thread_detach_func) {
4157                 gc_callbacks.thread_detach_func (p->runtime_data);
4158                 p->runtime_data = NULL;
4159         }
4160
4161         mono_threads_unregister_current_thread (p);
4162         UNLOCK_GC;
4163 }
4164
4165
4166 static void
4167 sgen_thread_attach (SgenThreadInfo *info)
4168 {
4169         LOCK_GC;
4170         /*this is odd, can we get attached before the gc is inited?*/
4171         init_stats ();
4172         UNLOCK_GC;
4173
4174         if (gc_callbacks.thread_attach_func && !info->runtime_data)
4175                 info->runtime_data = gc_callbacks.thread_attach_func ();
4176 }
4177 gboolean
4178 mono_gc_register_thread (void *baseptr)
4179 {
4180         return mono_thread_info_attach (baseptr) != NULL;
4181 }
4182
4183 /*
4184  * mono_gc_set_stack_end:
4185  *
4186  *   Set the end of the current threads stack to STACK_END. The stack space between
4187  * STACK_END and the real end of the threads stack will not be scanned during collections.
4188  */
4189 void
4190 mono_gc_set_stack_end (void *stack_end)
4191 {
4192         SgenThreadInfo *info;
4193
4194         LOCK_GC;
4195         info = mono_thread_info_current ();
4196         if (info) {
4197                 g_assert (stack_end < info->stack_end);
4198                 info->stack_end = stack_end;
4199         }
4200         UNLOCK_GC;
4201 }
4202
4203 #if USE_PTHREAD_INTERCEPT
4204
4205
4206 int
4207 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4208 {
4209         return pthread_create (new_thread, attr, start_routine, arg);
4210 }
4211
4212 int
4213 mono_gc_pthread_join (pthread_t thread, void **retval)
4214 {
4215         return pthread_join (thread, retval);
4216 }
4217
4218 int
4219 mono_gc_pthread_detach (pthread_t thread)
4220 {
4221         return pthread_detach (thread);
4222 }
4223
4224 void
4225 mono_gc_pthread_exit (void *retval)
4226 {
4227         pthread_exit (retval);
4228 }
4229
4230 #endif /* USE_PTHREAD_INTERCEPT */
4231
4232 /*
4233  * ######################################################################
4234  * ########  Write barriers
4235  * ######################################################################
4236  */
4237
4238 /*
4239  * Note: the write barriers first do the needed GC work and then do the actual store:
4240  * this way the value is visible to the conservative GC scan after the write barrier
4241  * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4242  * the conservative scan, otherwise by the remembered set scan.
4243  */
4244 void
4245 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4246 {
4247         HEAVY_STAT (++stat_wbarrier_set_field);
4248         if (ptr_in_nursery (field_ptr)) {
4249                 *(void**)field_ptr = value;
4250                 return;
4251         }
4252         SGEN_LOG (8, "Adding remset at %p", field_ptr);
4253         if (value)
4254                 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4255
4256         remset.wbarrier_set_field (obj, field_ptr, value);
4257 }
4258
4259 void
4260 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4261 {
4262         HEAVY_STAT (++stat_wbarrier_set_arrayref);
4263         if (ptr_in_nursery (slot_ptr)) {
4264                 *(void**)slot_ptr = value;
4265                 return;
4266         }
4267         SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4268         if (value)
4269                 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4270
4271         remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4272 }
4273
4274 void
4275 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4276 {
4277         HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4278         /*This check can be done without taking a lock since dest_ptr array is pinned*/
4279         if (ptr_in_nursery (dest_ptr) || count <= 0) {
4280                 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4281                 return;
4282         }
4283
4284 #ifdef SGEN_BINARY_PROTOCOL
4285         {
4286                 int i;
4287                 for (i = 0; i < count; ++i) {
4288                         gpointer dest = (gpointer*)dest_ptr + i;
4289                         gpointer obj = *((gpointer*)src_ptr + i);
4290                         if (obj)
4291                                 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4292                 }
4293         }
4294 #endif
4295
4296         remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4297 }
4298
4299 static char *found_obj;
4300
4301 static void
4302 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4303 {
4304         char *ptr = user_data;
4305
4306         if (ptr >= obj && ptr < obj + size) {
4307                 g_assert (!found_obj);
4308                 found_obj = obj;
4309         }
4310 }
4311
4312 /* for use in the debugger */
4313 char* find_object_for_ptr (char *ptr);
4314 char*
4315 find_object_for_ptr (char *ptr)
4316 {
4317         if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4318                 found_obj = NULL;
4319                 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4320                                 find_object_for_ptr_callback, ptr, TRUE);
4321                 if (found_obj)
4322                         return found_obj;
4323         }
4324
4325         found_obj = NULL;
4326         sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4327         if (found_obj)
4328                 return found_obj;
4329
4330         /*
4331          * Very inefficient, but this is debugging code, supposed to
4332          * be called from gdb, so we don't care.
4333          */
4334         found_obj = NULL;
4335         major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4336         return found_obj;
4337 }
4338
4339 void
4340 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4341 {
4342         gpointer obj;
4343
4344         HEAVY_STAT (++stat_wbarrier_generic_store);
4345
4346 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4347         /* FIXME: ptr_in_heap must be called with the GC lock held */
4348         if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4349                 char *start = find_object_for_ptr (ptr);
4350                 MonoObject *value = *(MonoObject**)ptr;
4351                 LOCK_GC;
4352                 g_assert (start);
4353                 if (start) {
4354                         MonoObject *obj = (MonoObject*)start;
4355                         if (obj->vtable->domain != value->vtable->domain)
4356                                 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4357                 }
4358                 UNLOCK_GC;
4359         }
4360 #endif
4361
4362         obj = *(gpointer*)ptr;
4363         if (obj)
4364                 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4365
4366         if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4367                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4368                 return;
4369         }
4370
4371         /*
4372          * We need to record old->old pointer locations for the
4373          * concurrent collector.
4374          */
4375         if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4376                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4377                 return;
4378         }
4379
4380         SGEN_LOG (8, "Adding remset at %p", ptr);
4381
4382         remset.wbarrier_generic_nostore (ptr);
4383 }
4384
4385 void
4386 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4387 {
4388         SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4389         *(void**)ptr = value;
4390         if (ptr_in_nursery (value))
4391                 mono_gc_wbarrier_generic_nostore (ptr);
4392         sgen_dummy_use (value);
4393 }
4394
4395 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4396 {
4397         mword *dest = _dest;
4398         mword *src = _src;
4399
4400         while (size) {
4401                 if (bitmap & 0x1)
4402                         mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4403                 else
4404                         *dest = *src;
4405                 ++src;
4406                 ++dest;
4407                 size -= SIZEOF_VOID_P;
4408                 bitmap >>= 1;
4409         }
4410 }
4411
4412 #ifdef SGEN_BINARY_PROTOCOL
4413 #undef HANDLE_PTR
4414 #define HANDLE_PTR(ptr,obj) do {                                        \
4415                 gpointer o = *(gpointer*)(ptr);                         \
4416                 if ((o)) {                                              \
4417                         gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4418                         binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4419                 }                                                       \
4420         } while (0)
4421
4422 static void
4423 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4424 {
4425 #define SCAN_OBJECT_NOVTABLE
4426 #include "sgen-scan-object.h"
4427 }
4428 #endif
4429
4430 void
4431 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4432 {
4433         HEAVY_STAT (++stat_wbarrier_value_copy);
4434         g_assert (klass->valuetype);
4435
4436         SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4437
4438         if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4439                 size_t element_size = mono_class_value_size (klass, NULL);
4440                 size_t size = count * element_size;
4441                 mono_gc_memmove (dest, src, size);
4442                 return;
4443         }
4444
4445 #ifdef SGEN_BINARY_PROTOCOL
4446         {
4447                 size_t element_size = mono_class_value_size (klass, NULL);
4448                 int i;
4449                 for (i = 0; i < count; ++i) {
4450                         scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4451                                         (char*)src + i * element_size - sizeof (MonoObject),
4452                                         (mword) klass->gc_descr);
4453                 }
4454         }
4455 #endif
4456
4457         remset.wbarrier_value_copy (dest, src, count, klass);
4458 }
4459
4460 /**
4461  * mono_gc_wbarrier_object_copy:
4462  *
4463  * Write barrier to call when obj is the result of a clone or copy of an object.
4464  */
4465 void
4466 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4467 {
4468         int size;
4469
4470         HEAVY_STAT (++stat_wbarrier_object_copy);
4471
4472         if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4473                 size = mono_object_class (obj)->instance_size;
4474                 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4475                                 size - sizeof (MonoObject));
4476                 return;
4477         }
4478
4479 #ifdef SGEN_BINARY_PROTOCOL
4480         scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4481 #endif
4482
4483         remset.wbarrier_object_copy (obj, src);
4484 }
4485
4486
4487 /*
4488  * ######################################################################
4489  * ########  Other mono public interface functions.
4490  * ######################################################################
4491  */
4492
4493 #define REFS_SIZE 128
4494 typedef struct {
4495         void *data;
4496         MonoGCReferences callback;
4497         int flags;
4498         int count;
4499         int called;
4500         MonoObject *refs [REFS_SIZE];
4501         uintptr_t offsets [REFS_SIZE];
4502 } HeapWalkInfo;
4503
4504 #undef HANDLE_PTR
4505 #define HANDLE_PTR(ptr,obj)     do {    \
4506                 if (*(ptr)) {   \
4507                         if (hwi->count == REFS_SIZE) {  \
4508                                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);    \
4509                                 hwi->count = 0; \
4510                                 hwi->called = 1;        \
4511                         }       \
4512                         hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start;  \
4513                         hwi->refs [hwi->count++] = *(ptr);      \
4514                 }       \
4515         } while (0)
4516
4517 static void
4518 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4519 {
4520 #include "sgen-scan-object.h"
4521 }
4522
4523 static void
4524 walk_references (char *start, size_t size, void *data)
4525 {
4526         HeapWalkInfo *hwi = data;
4527         hwi->called = 0;
4528         hwi->count = 0;
4529         collect_references (hwi, start, size);
4530         if (hwi->count || !hwi->called)
4531                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4532 }
4533
4534 /**
4535  * mono_gc_walk_heap:
4536  * @flags: flags for future use
4537  * @callback: a function pointer called for each object in the heap
4538  * @data: a user data pointer that is passed to callback
4539  *
4540  * This function can be used to iterate over all the live objects in the heap:
4541  * for each object, @callback is invoked, providing info about the object's
4542  * location in memory, its class, its size and the objects it references.
4543  * For each referenced object it's offset from the object address is
4544  * reported in the offsets array.
4545  * The object references may be buffered, so the callback may be invoked
4546  * multiple times for the same object: in all but the first call, the size
4547  * argument will be zero.
4548  * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4549  * profiler event handler.
4550  *
4551  * Returns: a non-zero value if the GC doesn't support heap walking
4552  */
4553 int
4554 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4555 {
4556         HeapWalkInfo hwi;
4557
4558         hwi.flags = flags;
4559         hwi.callback = callback;
4560         hwi.data = data;
4561
4562         sgen_clear_nursery_fragments ();
4563         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4564
4565         major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4566         sgen_los_iterate_objects (walk_references, &hwi);
4567
4568         return 0;
4569 }
4570
4571 void
4572 mono_gc_collect (int generation)
4573 {
4574         LOCK_GC;
4575         if (generation > 1)
4576                 generation = 1;
4577         sgen_perform_collection (0, generation, "user request", TRUE);
4578         UNLOCK_GC;
4579 }
4580
4581 int
4582 mono_gc_max_generation (void)
4583 {
4584         return 1;
4585 }
4586
4587 int
4588 mono_gc_collection_count (int generation)
4589 {
4590         if (generation == 0)
4591                 return stat_minor_gcs;
4592         return stat_major_gcs;
4593 }
4594
4595 int64_t
4596 mono_gc_get_used_size (void)
4597 {
4598         gint64 tot = 0;
4599         LOCK_GC;
4600         tot = los_memory_usage;
4601         tot += nursery_section->next_data - nursery_section->data;
4602         tot += major_collector.get_used_size ();
4603         /* FIXME: account for pinned objects */
4604         UNLOCK_GC;
4605         return tot;
4606 }
4607
4608 int
4609 mono_gc_get_los_limit (void)
4610 {
4611         return MAX_SMALL_OBJ_SIZE;
4612 }
4613
4614 gboolean
4615 mono_gc_user_markers_supported (void)
4616 {
4617         return TRUE;
4618 }
4619
4620 gboolean
4621 mono_object_is_alive (MonoObject* o)
4622 {
4623         return TRUE;
4624 }
4625
4626 int
4627 mono_gc_get_generation (MonoObject *obj)
4628 {
4629         if (ptr_in_nursery (obj))
4630                 return 0;
4631         return 1;
4632 }
4633
4634 void
4635 mono_gc_enable_events (void)
4636 {
4637 }
4638
4639 void
4640 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4641 {
4642         sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4643 }
4644
4645 void
4646 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4647 {
4648         sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4649 }
4650
4651 MonoObject*
4652 mono_gc_weak_link_get (void **link_addr)
4653 {
4654         void * volatile *link_addr_volatile;
4655         void *ptr;
4656         MonoObject *obj;
4657  retry:
4658         link_addr_volatile = link_addr;
4659         ptr = (void*)*link_addr_volatile;
4660         /*
4661          * At this point we have a hidden pointer.  If the GC runs
4662          * here, it will not recognize the hidden pointer as a
4663          * reference, and if the object behind it is not referenced
4664          * elsewhere, it will be freed.  Once the world is restarted
4665          * we reveal the pointer, giving us a pointer to a freed
4666          * object.  To make sure we don't return it, we load the
4667          * hidden pointer again.  If it's still the same, we can be
4668          * sure the object reference is valid.
4669          */
4670         if (ptr)
4671                 obj = (MonoObject*) REVEAL_POINTER (ptr);
4672         else
4673                 return NULL;
4674
4675         mono_memory_barrier ();
4676
4677         /*
4678          * During the second bridge processing step the world is
4679          * running again.  That step processes all weak links once
4680          * more to null those that refer to dead objects.  Before that
4681          * is completed, those links must not be followed, so we
4682          * conservatively wait for bridge processing when any weak
4683          * link is dereferenced.
4684          */
4685         if (G_UNLIKELY (bridge_processing_in_progress))
4686                 mono_gc_wait_for_bridge_processing ();
4687
4688         if ((void*)*link_addr_volatile != ptr)
4689                 goto retry;
4690
4691         return obj;
4692 }
4693
4694 gboolean
4695 mono_gc_ephemeron_array_add (MonoObject *obj)
4696 {
4697         EphemeronLinkNode *node;
4698
4699         LOCK_GC;
4700
4701         node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4702         if (!node) {
4703                 UNLOCK_GC;
4704                 return FALSE;
4705         }
4706         node->array = (char*)obj;
4707         node->next = ephemeron_list;
4708         ephemeron_list = node;
4709
4710         SGEN_LOG (5, "Registered ephemeron array %p", obj);
4711
4712         UNLOCK_GC;
4713         return TRUE;
4714 }
4715
4716 gboolean
4717 mono_gc_set_allow_synchronous_major (gboolean flag)
4718 {
4719         if (!major_collector.is_concurrent)
4720                 return flag;
4721
4722         allow_synchronous_major = flag;
4723         return TRUE;
4724 }
4725
4726 void*
4727 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4728 {
4729         void *result;
4730         LOCK_INTERRUPTION;
4731         result = func (data);
4732         UNLOCK_INTERRUPTION;
4733         return result;
4734 }
4735
4736 gboolean
4737 mono_gc_is_gc_thread (void)
4738 {
4739         gboolean result;
4740         LOCK_GC;
4741         result = mono_thread_info_current () != NULL;
4742         UNLOCK_GC;
4743         return result;
4744 }
4745
4746 static gboolean
4747 is_critical_method (MonoMethod *method)
4748 {
4749         return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4750 }
4751
4752 void
4753 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4754 {
4755         va_list ap;
4756
4757         va_start (ap, description_format);
4758
4759         fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4760         vfprintf (stderr, description_format, ap);
4761         if (fallback)
4762                 fprintf (stderr, " - %s", fallback);
4763         fprintf (stderr, "\n");
4764
4765         va_end (ap);
4766 }
4767
4768 static gboolean
4769 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4770 {
4771         char *endptr;
4772         double val = strtod (opt, &endptr);
4773         if (endptr == opt) {
4774                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4775                 return FALSE;
4776         }
4777         else if (val < min || val > max) {
4778                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4779                 return FALSE;
4780         }
4781         *result = val;
4782         return TRUE;
4783 }
4784
4785 void
4786 mono_gc_base_init (void)
4787 {
4788         MonoThreadInfoCallbacks cb;
4789         char *env;
4790         char **opts, **ptr;
4791         char *major_collector_opt = NULL;
4792         char *minor_collector_opt = NULL;
4793         glong max_heap = 0;
4794         glong soft_limit = 0;
4795         int num_workers;
4796         int result;
4797         int dummy;
4798         gboolean debug_print_allowance = FALSE;
4799         double allowance_ratio = 0, save_target = 0;
4800         gboolean have_split_nursery = FALSE;
4801         gboolean cement_enabled = TRUE;
4802
4803         do {
4804                 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4805                 switch (result) {
4806                 case 1:
4807                         /* already inited */
4808                         return;
4809                 case -1:
4810                         /* being inited by another thread */
4811                         g_usleep (1000);
4812                         break;
4813                 case 0:
4814                         /* we will init it */
4815                         break;
4816                 default:
4817                         g_assert_not_reached ();
4818                 }
4819         } while (result != 0);
4820
4821         LOCK_INIT (gc_mutex);
4822
4823         pagesize = mono_pagesize ();
4824         gc_debug_file = stderr;
4825
4826         cb.thread_register = sgen_thread_register;
4827         cb.thread_unregister = sgen_thread_unregister;
4828         cb.thread_attach = sgen_thread_attach;
4829         cb.mono_method_is_critical = (gpointer)is_critical_method;
4830 #ifndef HOST_WIN32
4831         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4832 #endif
4833
4834         mono_threads_init (&cb, sizeof (SgenThreadInfo));
4835
4836         LOCK_INIT (sgen_interruption_mutex);
4837         LOCK_INIT (pin_queue_mutex);
4838
4839         init_user_copy_or_mark_key ();
4840
4841         if ((env = getenv (MONO_GC_PARAMS_NAME))) {
4842                 opts = g_strsplit (env, ",", -1);
4843                 for (ptr = opts; *ptr; ++ptr) {
4844                         char *opt = *ptr;
4845                         if (g_str_has_prefix (opt, "major=")) {
4846                                 opt = strchr (opt, '=') + 1;
4847                                 major_collector_opt = g_strdup (opt);
4848                         } else if (g_str_has_prefix (opt, "minor=")) {
4849                                 opt = strchr (opt, '=') + 1;
4850                                 minor_collector_opt = g_strdup (opt);
4851                         }
4852                 }
4853         } else {
4854                 opts = NULL;
4855         }
4856
4857         init_stats ();
4858         sgen_init_internal_allocator ();
4859         sgen_init_nursery_allocator ();
4860
4861         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4862         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4863         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4864         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4865
4866 #ifndef HAVE_KW_THREAD
4867         mono_native_tls_alloc (&thread_info_key, NULL);
4868 #endif
4869
4870         /*
4871          * This needs to happen before any internal allocations because
4872          * it inits the small id which is required for hazard pointer
4873          * operations.
4874          */
4875         sgen_os_init ();
4876
4877         mono_thread_info_attach (&dummy);
4878
4879         if (!minor_collector_opt) {
4880                 sgen_simple_nursery_init (&sgen_minor_collector);
4881         } else {
4882                 if (!strcmp (minor_collector_opt, "simple")) {
4883                 use_simple_nursery:
4884                         sgen_simple_nursery_init (&sgen_minor_collector);
4885                 } else if (!strcmp (minor_collector_opt, "split")) {
4886                         sgen_split_nursery_init (&sgen_minor_collector);
4887                         have_split_nursery = TRUE;
4888                 } else {
4889                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4890                         goto use_simple_nursery;
4891                 }
4892         }
4893
4894         if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4895         use_marksweep_major:
4896                 sgen_marksweep_init (&major_collector);
4897         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4898                 sgen_marksweep_fixed_init (&major_collector);
4899         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4900                 sgen_marksweep_par_init (&major_collector);
4901         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4902                 sgen_marksweep_fixed_par_init (&major_collector);
4903         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4904                 sgen_marksweep_conc_init (&major_collector);
4905         } else {
4906                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4907                 goto use_marksweep_major;
4908         }
4909
4910         if (have_split_nursery && major_collector.is_parallel) {
4911                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4912                 have_split_nursery = FALSE;
4913         }
4914
4915         num_workers = mono_cpu_count ();
4916         g_assert (num_workers > 0);
4917         if (num_workers > 16)
4918                 num_workers = 16;
4919
4920         ///* Keep this the default for now */
4921         /* Precise marking is broken on all supported targets. Disable until fixed. */
4922         conservative_stack_mark = TRUE;
4923
4924         sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4925
4926         if (opts) {
4927                 gboolean usage_printed = FALSE;
4928
4929                 for (ptr = opts; *ptr; ++ptr) {
4930                         char *opt = *ptr;
4931                         if (!strcmp (opt, ""))
4932                                 continue;
4933                         if (g_str_has_prefix (opt, "major="))
4934                                 continue;
4935                         if (g_str_has_prefix (opt, "minor="))
4936                                 continue;
4937                         if (g_str_has_prefix (opt, "max-heap-size=")) {
4938                                 glong max_heap_candidate = 0;
4939                                 opt = strchr (opt, '=') + 1;
4940                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4941                                         max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(glong)(mono_pagesize () - 1);
4942                                         if (max_heap != max_heap_candidate)
4943                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4944                                 } else {
4945                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4946                                 }
4947                                 continue;
4948                         }
4949                         if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4950                                 opt = strchr (opt, '=') + 1;
4951                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4952                                         if (soft_limit <= 0) {
4953                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4954                                                 soft_limit = 0;
4955                                         }
4956                                 } else {
4957                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4958                                 }
4959                                 continue;
4960                         }
4961                         if (g_str_has_prefix (opt, "workers=")) {
4962                                 long val;
4963                                 char *endptr;
4964                                 if (!major_collector.is_parallel) {
4965                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
4966                                         continue;
4967                                 }
4968                                 opt = strchr (opt, '=') + 1;
4969                                 val = strtol (opt, &endptr, 10);
4970                                 if (!*opt || *endptr) {
4971                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
4972                                         continue;
4973                                 }
4974                                 if (val <= 0 || val > 16) {
4975                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
4976                                         continue;
4977                                 }
4978                                 num_workers = (int)val;
4979                                 continue;
4980                         }
4981                         if (g_str_has_prefix (opt, "stack-mark=")) {
4982                                 opt = strchr (opt, '=') + 1;
4983                                 if (!strcmp (opt, "precise")) {
4984                                         conservative_stack_mark = FALSE;
4985                                 } else if (!strcmp (opt, "conservative")) {
4986                                         conservative_stack_mark = TRUE;
4987                                 } else {
4988                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4989                                                         "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4990                                 }
4991                                 continue;
4992                         }
4993                         if (g_str_has_prefix (opt, "bridge=")) {
4994                                 opt = strchr (opt, '=') + 1;
4995                                 sgen_register_test_bridge_callbacks (g_strdup (opt));
4996                                 continue;
4997                         }
4998 #ifdef USER_CONFIG
4999                         if (g_str_has_prefix (opt, "nursery-size=")) {
5000                                 long val;
5001                                 opt = strchr (opt, '=') + 1;
5002                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
5003 #ifdef SGEN_ALIGN_NURSERY
5004                                         if ((val & (val - 1))) {
5005                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
5006                                                 continue;
5007                                         }
5008
5009                                         if (val < SGEN_MAX_NURSERY_WASTE) {
5010                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
5011                                                                 "`nursery-size` must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
5012                                                 continue;
5013                                         }
5014
5015                                         sgen_nursery_size = val;
5016                                         sgen_nursery_bits = 0;
5017                                         while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
5018                                                 ;
5019 #else
5020                                         sgen_nursery_size = val;
5021 #endif
5022                                 } else {
5023                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
5024                                         continue;
5025                                 }
5026                                 continue;
5027                         }
5028 #endif
5029                         if (g_str_has_prefix (opt, "save-target-ratio=")) {
5030                                 double val;
5031                                 opt = strchr (opt, '=') + 1;
5032                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
5033                                                 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
5034                                         save_target = val;
5035                                 }
5036                                 continue;
5037                         }
5038                         if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
5039                                 double val;
5040                                 opt = strchr (opt, '=') + 1;
5041                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
5042                                                 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
5043                                         allowance_ratio = val;
5044                                 }
5045                                 continue;
5046                         }
5047                         if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
5048                                 if (!major_collector.is_concurrent) {
5049                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
5050                                         continue;
5051                                 }
5052
5053                                 opt = strchr (opt, '=') + 1;
5054
5055                                 if (!strcmp (opt, "yes")) {
5056                                         allow_synchronous_major = TRUE;
5057                                 } else if (!strcmp (opt, "no")) {
5058                                         allow_synchronous_major = FALSE;
5059                                 } else {
5060                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
5061                                         continue;
5062                                 }
5063                         }
5064
5065                         if (!strcmp (opt, "cementing")) {
5066                                 cement_enabled = TRUE;
5067                                 continue;
5068                         }
5069                         if (!strcmp (opt, "no-cementing")) {
5070                                 cement_enabled = FALSE;
5071                                 continue;
5072                         }
5073
5074                         if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
5075                                 continue;
5076
5077                         if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
5078                                 continue;
5079
5080                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5081
5082                         if (usage_printed)
5083                                 continue;
5084
5085                         fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
5086                         fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5087                         fprintf (stderr, "  soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
5088                         fprintf (stderr, "  nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5089                         fprintf (stderr, "  major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
5090                         fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
5091                         fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
5092                         fprintf (stderr, "  stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
5093                         fprintf (stderr, "  [no-]cementing\n");
5094                         if (major_collector.is_concurrent)
5095                                 fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
5096                         if (major_collector.print_gc_param_usage)
5097                                 major_collector.print_gc_param_usage ();
5098                         if (sgen_minor_collector.print_gc_param_usage)
5099                                 sgen_minor_collector.print_gc_param_usage ();
5100                         fprintf (stderr, " Experimental options:\n");
5101                         fprintf (stderr, "  save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
5102                         fprintf (stderr, "  default-allowance-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO);
5103                         fprintf (stderr, "\n");
5104
5105                         usage_printed = TRUE;
5106                 }
5107                 g_strfreev (opts);
5108         }
5109
5110         if (major_collector.is_parallel)
5111                 sgen_workers_init (num_workers);
5112         else if (major_collector.is_concurrent)
5113                 sgen_workers_init (1);
5114
5115         if (major_collector_opt)
5116                 g_free (major_collector_opt);
5117
5118         if (minor_collector_opt)
5119                 g_free (minor_collector_opt);
5120
5121         alloc_nursery ();
5122
5123         sgen_cement_init (cement_enabled);
5124
5125         if ((env = getenv (MONO_GC_DEBUG_NAME))) {
5126                 gboolean usage_printed = FALSE;
5127
5128                 opts = g_strsplit (env, ",", -1);
5129                 for (ptr = opts; ptr && *ptr; ptr ++) {
5130                         char *opt = *ptr;
5131                         if (!strcmp (opt, ""))
5132                                 continue;
5133                         if (opt [0] >= '0' && opt [0] <= '9') {
5134                                 gc_debug_level = atoi (opt);
5135                                 opt++;
5136                                 if (opt [0] == ':')
5137                                         opt++;
5138                                 if (opt [0]) {
5139 #ifdef HOST_WIN32
5140                                         char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
5141 #else
5142                                         char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
5143 #endif
5144                                         gc_debug_file = fopen (rf, "wb");
5145                                         if (!gc_debug_file)
5146                                                 gc_debug_file = stderr;
5147                                         g_free (rf);
5148                                 }
5149                         } else if (!strcmp (opt, "print-allowance")) {
5150                                 debug_print_allowance = TRUE;
5151                         } else if (!strcmp (opt, "print-pinning")) {
5152                                 do_pin_stats = TRUE;
5153                         } else if (!strcmp (opt, "verify-before-allocs")) {
5154                                 verify_before_allocs = 1;
5155                                 has_per_allocation_action = TRUE;
5156                         } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5157                                 char *arg = strchr (opt, '=') + 1;
5158                                 verify_before_allocs = atoi (arg);
5159                                 has_per_allocation_action = TRUE;
5160                         } else if (!strcmp (opt, "collect-before-allocs")) {
5161                                 collect_before_allocs = 1;
5162                                 has_per_allocation_action = TRUE;
5163                         } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5164                                 char *arg = strchr (opt, '=') + 1;
5165                                 has_per_allocation_action = TRUE;
5166                                 collect_before_allocs = atoi (arg);
5167                         } else if (!strcmp (opt, "verify-before-collections")) {
5168                                 whole_heap_check_before_collection = TRUE;
5169                         } else if (!strcmp (opt, "check-at-minor-collections")) {
5170                                 consistency_check_at_minor_collection = TRUE;
5171                                 nursery_clear_policy = CLEAR_AT_GC;
5172                         } else if (!strcmp (opt, "check-mark-bits")) {
5173                                 check_mark_bits_after_major_collection = TRUE;
5174                         } else if (!strcmp (opt, "check-nursery-pinned")) {
5175                                 check_nursery_objects_pinned = TRUE;
5176                         } else if (!strcmp (opt, "xdomain-checks")) {
5177                                 xdomain_checks = TRUE;
5178                         } else if (!strcmp (opt, "clear-at-gc")) {
5179                                 nursery_clear_policy = CLEAR_AT_GC;
5180                         } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5181                                 nursery_clear_policy = CLEAR_AT_GC;
5182                         } else if (!strcmp (opt, "check-scan-starts")) {
5183                                 do_scan_starts_check = TRUE;
5184                         } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5185                                 do_verify_nursery = TRUE;
5186                         } else if (!strcmp (opt, "check-concurrent")) {
5187                                 if (!major_collector.is_concurrent) {
5188                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5189                                         continue;
5190                                 }
5191                                 do_concurrent_checks = TRUE;
5192                         } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5193                                 do_dump_nursery_content = TRUE;
5194                         } else if (!strcmp (opt, "no-managed-allocator")) {
5195                                 sgen_set_use_managed_allocator (FALSE);
5196                         } else if (!strcmp (opt, "disable-minor")) {
5197                                 disable_minor_collections = TRUE;
5198                         } else if (!strcmp (opt, "disable-major")) {
5199                                 disable_major_collections = TRUE;
5200                         } else if (g_str_has_prefix (opt, "heap-dump=")) {
5201                                 char *filename = strchr (opt, '=') + 1;
5202                                 nursery_clear_policy = CLEAR_AT_GC;
5203                                 heap_dump_file = fopen (filename, "w");
5204                                 if (heap_dump_file) {
5205                                         fprintf (heap_dump_file, "<sgen-dump>\n");
5206                                         do_pin_stats = TRUE;
5207                                 }
5208 #ifdef SGEN_BINARY_PROTOCOL
5209                         } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5210                                 char *filename = strchr (opt, '=') + 1;
5211                                 binary_protocol_init (filename);
5212 #endif
5213                         } else {
5214                                 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5215
5216                                 if (usage_printed)
5217                                         continue;
5218
5219                                 fprintf (stderr, "\n%s must be of the format [<l>[:<filename>]|<option>]+ where <l> is a debug level 0-9.\n", MONO_GC_DEBUG_NAME);
5220                                 fprintf (stderr, "Valid <option>s are:\n");
5221                                 fprintf (stderr, "  collect-before-allocs[=<n>]\n");
5222                                 fprintf (stderr, "  verify-before-allocs[=<n>]\n");
5223                                 fprintf (stderr, "  check-at-minor-collections\n");
5224                                 fprintf (stderr, "  check-mark-bits\n");
5225                                 fprintf (stderr, "  check-nursery-pinned\n");
5226                                 fprintf (stderr, "  verify-before-collections\n");
5227                                 fprintf (stderr, "  verify-nursery-at-minor-gc\n");
5228                                 fprintf (stderr, "  dump-nursery-at-minor-gc\n");
5229                                 fprintf (stderr, "  disable-minor\n");
5230                                 fprintf (stderr, "  disable-major\n");
5231                                 fprintf (stderr, "  xdomain-checks\n");
5232                                 fprintf (stderr, "  check-concurrent\n");
5233                                 fprintf (stderr, "  clear-at-gc\n");
5234                                 fprintf (stderr, "  clear-nursery-at-gc\n");
5235                                 fprintf (stderr, "  check-scan-starts\n");
5236                                 fprintf (stderr, "  no-managed-allocator\n");
5237                                 fprintf (stderr, "  print-allowance\n");
5238                                 fprintf (stderr, "  print-pinning\n");
5239                                 fprintf (stderr, "  heap-dump=<filename>\n");
5240 #ifdef SGEN_BINARY_PROTOCOL
5241                                 fprintf (stderr, "  binary-protocol=<filename>\n");
5242 #endif
5243                                 fprintf (stderr, "\n");
5244
5245                                 usage_printed = TRUE;
5246                         }
5247                 }
5248                 g_strfreev (opts);
5249         }
5250
5251         if (major_collector.is_parallel) {
5252                 if (heap_dump_file) {
5253                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5254                         fclose (heap_dump_file);
5255                         heap_dump_file = NULL;
5256                 }
5257                 if (do_pin_stats) {
5258                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5259                         do_pin_stats = FALSE;
5260                 }
5261         }
5262
5263         if (major_collector.post_param_init)
5264                 major_collector.post_param_init (&major_collector);
5265
5266         sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5267
5268         memset (&remset, 0, sizeof (remset));
5269
5270         sgen_card_table_init (&remset);
5271
5272         gc_initialized = 1;
5273 }
5274
5275 const char *
5276 mono_gc_get_gc_name (void)
5277 {
5278         return "sgen";
5279 }
5280
5281 static MonoMethod *write_barrier_method;
5282
5283 gboolean
5284 sgen_is_critical_method (MonoMethod *method)
5285 {
5286         return (method == write_barrier_method || sgen_is_managed_allocator (method));
5287 }
5288
5289 gboolean
5290 sgen_has_critical_method (void)
5291 {
5292         return write_barrier_method || sgen_has_managed_allocator ();
5293 }
5294
5295 #ifndef DISABLE_JIT
5296
5297 static void
5298 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5299 {
5300         memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5301 #ifdef SGEN_ALIGN_NURSERY
5302         // if (ptr_in_nursery (ptr)) return;
5303         /*
5304          * Masking out the bits might be faster, but we would have to use 64 bit
5305          * immediates, which might be slower.
5306          */
5307         mono_mb_emit_ldarg (mb, 0);
5308         mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5309         mono_mb_emit_byte (mb, CEE_SHR_UN);
5310         mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5311         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5312
5313         if (!major_collector.is_concurrent) {
5314                 // if (!ptr_in_nursery (*ptr)) return;
5315                 mono_mb_emit_ldarg (mb, 0);
5316                 mono_mb_emit_byte (mb, CEE_LDIND_I);
5317                 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5318                 mono_mb_emit_byte (mb, CEE_SHR_UN);
5319                 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5320                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5321         }
5322 #else
5323         int label_continue1, label_continue2;
5324         int dereferenced_var;
5325
5326         // if (ptr < (sgen_get_nursery_start ())) goto continue;
5327         mono_mb_emit_ldarg (mb, 0);
5328         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5329         label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5330
5331         // if (ptr >= sgen_get_nursery_end ())) goto continue;
5332         mono_mb_emit_ldarg (mb, 0);
5333         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5334         label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5335
5336         // Otherwise return
5337         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5338
5339         // continue:
5340         mono_mb_patch_branch (mb, label_continue_1);
5341         mono_mb_patch_branch (mb, label_continue_2);
5342
5343         // Dereference and store in local var
5344         dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5345         mono_mb_emit_ldarg (mb, 0);
5346         mono_mb_emit_byte (mb, CEE_LDIND_I);
5347         mono_mb_emit_stloc (mb, dereferenced_var);
5348
5349         if (!major_collector.is_concurrent) {
5350                 // if (*ptr < sgen_get_nursery_start ()) return;
5351                 mono_mb_emit_ldloc (mb, dereferenced_var);
5352                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5353                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5354
5355                 // if (*ptr >= sgen_get_nursery_end ()) return;
5356                 mono_mb_emit_ldloc (mb, dereferenced_var);
5357                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5358                 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5359         }
5360 #endif
5361 }
5362 #endif
5363
5364 MonoMethod*
5365 mono_gc_get_write_barrier (void)
5366 {
5367         MonoMethod *res;
5368         MonoMethodBuilder *mb;
5369         MonoMethodSignature *sig;
5370 #ifdef MANAGED_WBARRIER
5371         int i, nursery_check_labels [3];
5372
5373 #ifdef HAVE_KW_THREAD
5374         int stack_end_offset = -1;
5375
5376         MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5377         g_assert (stack_end_offset != -1);
5378 #endif
5379 #endif
5380
5381         // FIXME: Maybe create a separate version for ctors (the branch would be
5382         // correctly predicted more times)
5383         if (write_barrier_method)
5384                 return write_barrier_method;
5385
5386         /* Create the IL version of mono_gc_barrier_generic_store () */
5387         sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5388         sig->ret = &mono_defaults.void_class->byval_arg;
5389         sig->params [0] = &mono_defaults.int_class->byval_arg;
5390
5391         mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5392
5393 #ifndef DISABLE_JIT
5394 #ifdef MANAGED_WBARRIER
5395         emit_nursery_check (mb, nursery_check_labels);
5396         /*
5397         addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5398         *addr = 1;
5399
5400         sgen_cardtable:
5401                 LDC_PTR sgen_cardtable
5402
5403         address >> CARD_BITS
5404                 LDARG_0
5405                 LDC_I4 CARD_BITS
5406                 SHR_UN
5407         if (SGEN_HAVE_OVERLAPPING_CARDS) {
5408                 LDC_PTR card_table_mask
5409                 AND
5410         }
5411         AND
5412         ldc_i4_1
5413         stind_i1
5414         */
5415         mono_mb_emit_ptr (mb, sgen_cardtable);
5416         mono_mb_emit_ldarg (mb, 0);
5417         mono_mb_emit_icon (mb, CARD_BITS);
5418         mono_mb_emit_byte (mb, CEE_SHR_UN);
5419 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5420         mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5421         mono_mb_emit_byte (mb, CEE_AND);
5422 #endif
5423         mono_mb_emit_byte (mb, CEE_ADD);
5424         mono_mb_emit_icon (mb, 1);
5425         mono_mb_emit_byte (mb, CEE_STIND_I1);
5426
5427         // return;
5428         for (i = 0; i < 3; ++i) {
5429                 if (nursery_check_labels [i])
5430                         mono_mb_patch_branch (mb, nursery_check_labels [i]);
5431         }
5432         mono_mb_emit_byte (mb, CEE_RET);
5433 #else
5434         mono_mb_emit_ldarg (mb, 0);
5435         mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5436         mono_mb_emit_byte (mb, CEE_RET);
5437 #endif
5438 #endif
5439         res = mono_mb_create_method (mb, sig, 16);
5440         mono_mb_free (mb);
5441
5442         mono_loader_lock ();
5443         if (write_barrier_method) {
5444                 /* Already created */
5445                 mono_free_method (res);
5446         } else {
5447                 /* double-checked locking */
5448                 mono_memory_barrier ();
5449                 write_barrier_method = res;
5450         }
5451         mono_loader_unlock ();
5452
5453         return write_barrier_method;
5454 }
5455
5456 char*
5457 mono_gc_get_description (void)
5458 {
5459         return g_strdup ("sgen");
5460 }
5461
5462 void
5463 mono_gc_set_desktop_mode (void)
5464 {
5465 }
5466
5467 gboolean
5468 mono_gc_is_moving (void)
5469 {
5470         return TRUE;
5471 }
5472
5473 gboolean
5474 mono_gc_is_disabled (void)
5475 {
5476         return FALSE;
5477 }
5478
5479 #ifdef HOST_WIN32
5480 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5481 {
5482         return TRUE;
5483 }
5484 #endif
5485
5486 NurseryClearPolicy
5487 sgen_get_nursery_clear_policy (void)
5488 {
5489         return nursery_clear_policy;
5490 }
5491
5492 MonoVTable*
5493 sgen_get_array_fill_vtable (void)
5494 {
5495         if (!array_fill_vtable) {
5496                 static MonoClass klass;
5497                 static MonoVTable vtable;
5498                 gsize bmap;
5499
5500                 MonoDomain *domain = mono_get_root_domain ();
5501                 g_assert (domain);
5502
5503                 klass.element_class = mono_defaults.byte_class;
5504                 klass.rank = 1;
5505                 klass.instance_size = sizeof (MonoArray);
5506                 klass.sizes.element_size = 1;
5507                 klass.name = "array_filler_type";
5508
5509                 vtable.klass = &klass;
5510                 bmap = 0;
5511                 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5512                 vtable.rank = 1;
5513
5514                 array_fill_vtable = &vtable;
5515         }
5516         return array_fill_vtable;
5517 }
5518
5519 void
5520 sgen_gc_lock (void)
5521 {
5522         LOCK_GC;
5523 }
5524
5525 void
5526 sgen_gc_unlock (void)
5527 {
5528         UNLOCK_GC;
5529 }
5530
5531 void
5532 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5533 {
5534         major_collector.iterate_live_block_ranges (callback);
5535 }
5536
5537 void
5538 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5539 {
5540         major_collector.scan_card_table (FALSE, queue);
5541 }
5542
5543 SgenMajorCollector*
5544 sgen_get_major_collector (void)
5545 {
5546         return &major_collector;
5547 }
5548
5549 void mono_gc_set_skip_thread (gboolean skip)
5550 {
5551         SgenThreadInfo *info = mono_thread_info_current ();
5552
5553         LOCK_GC;
5554         info->gc_disabled = skip;
5555         UNLOCK_GC;
5556 }
5557
5558 SgenRemeberedSet*
5559 sgen_get_remset (void)
5560 {
5561         return &remset;
5562 }
5563
5564 guint
5565 mono_gc_get_vtable_bits (MonoClass *class)
5566 {
5567         if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5568                 return SGEN_GC_BIT_BRIDGE_OBJECT;
5569         return 0;
5570 }
5571
5572 void
5573 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5574 {
5575         // FIXME:
5576 }
5577
5578
5579 void
5580 sgen_check_whole_heap_stw (void)
5581 {
5582         sgen_stop_world (0);
5583         sgen_clear_nursery_fragments ();
5584         sgen_check_whole_heap (FALSE);
5585         sgen_restart_world (0, NULL);
5586 }
5587
5588 void
5589 sgen_gc_event_moves (void)
5590 {
5591         if (moved_objects_idx) {
5592                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5593                 moved_objects_idx = 0;
5594         }
5595 }
5596
5597 #endif /* HAVE_SGEN_GC */