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 "metadata/sgen-layout-stats.h"
 218 #include "utils/mono-mmap.h"
 219 #include "utils/mono-time.h"
 220 #include "utils/mono-semaphore.h"
 221 #include "utils/mono-counters.h"
 222 #include "utils/mono-proclib.h"
 223 #include "utils/mono-memory-model.h"
 224 #include "utils/mono-logger-internal.h"
 225 #include "utils/dtrace.h"
 226
 227 #include <mono/utils/mono-logger-internal.h>
 228 #include <mono/utils/memcheck.h>
 229
 230 #if defined(__MACH__)
 231 #include "utils/mach-support.h"
 232 #endif
 233
 234 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
 235         a = i,
 236
 237 enum {
 238 #include "mono/cil/opcode.def"
 239         CEE_LAST
 240 };
 241
 242 #undef OPDEF
 243
 244 #undef pthread_create
 245 #undef pthread_join
 246 #undef pthread_detach
 247
 248 /*
 249  * ######################################################################
 250  * ########  Types and constants used by the GC.
 251  * ######################################################################
 252  */
 253
 254 /* 0 means not initialized, 1 is initialized, -1 means in progress */
 255 static int gc_initialized = 0;
 256 /* If set, check if we need to do something every X allocations */
 257 gboolean has_per_allocation_action;
 258 /* If set, do a heap check every X allocation */
 259 guint32 verify_before_allocs = 0;
 260 /* If set, do a minor collection before every X allocation */
 261 guint32 collect_before_allocs = 0;
 262 /* If set, do a whole heap check before each collection */
 263 static gboolean whole_heap_check_before_collection = FALSE;
 264 /* If set, do a heap consistency check before each minor collection */
 265 static gboolean consistency_check_at_minor_collection = FALSE;
 266 /* If set, do a mod union consistency check before each finishing collection pause */
 267 static gboolean mod_union_consistency_check = FALSE;
 268 /* If set, check whether mark bits are consistent after major collections */
 269 static gboolean check_mark_bits_after_major_collection = FALSE;
 270 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
 271 static gboolean check_nursery_objects_pinned = FALSE;
 272 /* If set, do a few checks when the concurrent collector is used */
 273 static gboolean do_concurrent_checks = FALSE;
 274 /* If set, check that there are no references to the domain left at domain unload */
 275 static gboolean xdomain_checks = FALSE;
 276 /* If not null, dump the heap after each collection into this file */
 277 static FILE *heap_dump_file = NULL;
 278 /* If set, mark stacks conservatively, even if precise marking is possible */
 279 static gboolean conservative_stack_mark = FALSE;
 280 /* If set, do a plausibility check on the scan_starts before and after
 281    each collection */
 282 static gboolean do_scan_starts_check = FALSE;
 283 /*
 284  * If the major collector is concurrent and this is FALSE, we will
 285  * never initiate a synchronous major collection, unless requested via
 286  * GC.Collect().
 287  */
 288 static gboolean allow_synchronous_major = TRUE;
 289 static gboolean nursery_collection_is_parallel = FALSE;
 290 static gboolean disable_minor_collections = FALSE;
 291 static gboolean disable_major_collections = FALSE;
 292 gboolean do_pin_stats = FALSE;
 293 static gboolean do_verify_nursery = FALSE;
 294 static gboolean do_dump_nursery_content = FALSE;
 295
 296 #ifdef HEAVY_STATISTICS
 297 long long stat_objects_alloced_degraded = 0;
 298 long long stat_bytes_alloced_degraded = 0;
 299
 300 long long stat_copy_object_called_nursery = 0;
 301 long long stat_objects_copied_nursery = 0;
 302 long long stat_copy_object_called_major = 0;
 303 long long stat_objects_copied_major = 0;
 304
 305 long long stat_scan_object_called_nursery = 0;
 306 long long stat_scan_object_called_major = 0;
 307
 308 long long stat_slots_allocated_in_vain;
 309
 310 long long stat_nursery_copy_object_failed_from_space = 0;
 311 long long stat_nursery_copy_object_failed_forwarded = 0;
 312 long long stat_nursery_copy_object_failed_pinned = 0;
 313 long long stat_nursery_copy_object_failed_to_space = 0;
 314
 315 static int stat_wbarrier_add_to_global_remset = 0;
 316 static int stat_wbarrier_set_field = 0;
 317 static int stat_wbarrier_set_arrayref = 0;
 318 static int stat_wbarrier_arrayref_copy = 0;
 319 static int stat_wbarrier_generic_store = 0;
 320 static int stat_wbarrier_set_root = 0;
 321 static int stat_wbarrier_value_copy = 0;
 322 static int stat_wbarrier_object_copy = 0;
 323 #endif
 324
 325 int stat_minor_gcs = 0;
 326 int stat_major_gcs = 0;
 327
 328 static long long stat_pinned_objects = 0;
 329
 330 static long long time_minor_pre_collection_fragment_clear = 0;
 331 static long long time_minor_pinning = 0;
 332 static long long time_minor_scan_remsets = 0;
 333 static long long time_minor_scan_pinned = 0;
 334 static long long time_minor_scan_registered_roots = 0;
 335 static long long time_minor_scan_thread_data = 0;
 336 static long long time_minor_finish_gray_stack = 0;
 337 static long long time_minor_fragment_creation = 0;
 338
 339 static long long time_major_pre_collection_fragment_clear = 0;
 340 static long long time_major_pinning = 0;
 341 static long long time_major_scan_pinned = 0;
 342 static long long time_major_scan_registered_roots = 0;
 343 static long long time_major_scan_thread_data = 0;
 344 static long long time_major_scan_alloc_pinned = 0;
 345 static long long time_major_scan_finalized = 0;
 346 static long long time_major_scan_big_objects = 0;
 347 static long long time_major_finish_gray_stack = 0;
 348 static long long time_major_free_bigobjs = 0;
 349 static long long time_major_los_sweep = 0;
 350 static long long time_major_sweep = 0;
 351 static long long time_major_fragment_creation = 0;
 352
 353 int gc_debug_level = 0;
 354 FILE* gc_debug_file;
 355
 356 /*
 357 void
 358 mono_gc_flush_info (void)
 359 {
 360         fflush (gc_debug_file);
 361 }
 362 */
 363
 364 #define TV_DECLARE SGEN_TV_DECLARE
 365 #define TV_GETTIME SGEN_TV_GETTIME
 366 #define TV_ELAPSED SGEN_TV_ELAPSED
 367 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
 368
 369 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
 370
 371 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
 372
 373 #define object_is_forwarded     SGEN_OBJECT_IS_FORWARDED
 374 #define object_is_pinned        SGEN_OBJECT_IS_PINNED
 375 #define pin_object              SGEN_PIN_OBJECT
 376 #define unpin_object            SGEN_UNPIN_OBJECT
 377
 378 #define ptr_in_nursery sgen_ptr_in_nursery
 379
 380 #define LOAD_VTABLE     SGEN_LOAD_VTABLE
 381
 382 static const char*
 383 safe_name (void* obj)
 384 {
 385         MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
 386         return vt->klass->name;
 387 }
 388
 389 #define safe_object_get_size    sgen_safe_object_get_size
 390
 391 const char*
 392 sgen_safe_name (void* obj)
 393 {
 394         return safe_name (obj);
 395 }
 396
 397 /*
 398  * ######################################################################
 399  * ########  Global data.
 400  * ######################################################################
 401  */
 402 LOCK_DECLARE (gc_mutex);
 403
 404 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
 405
 406 static mword pagesize = 4096;
 407 int degraded_mode = 0;
 408
 409 static mword bytes_pinned_from_failed_allocation = 0;
 410
 411 GCMemSection *nursery_section = NULL;
 412 static mword lowest_heap_address = ~(mword)0;
 413 static mword highest_heap_address = 0;
 414
 415 LOCK_DECLARE (sgen_interruption_mutex);
 416 static LOCK_DECLARE (pin_queue_mutex);
 417
 418 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
 419 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
 420
 421 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
 422 struct _FinalizeReadyEntry {
 423         FinalizeReadyEntry *next;
 424         void *object;
 425 };
 426
 427 typedef struct _EphemeronLinkNode EphemeronLinkNode;
 428
 429 struct _EphemeronLinkNode {
 430         EphemeronLinkNode *next;
 431         char *array;
 432 };
 433
 434 typedef struct {
 435        void *key;
 436        void *value;
 437 } Ephemeron;
 438
 439 int current_collection_generation = -1;
 440 volatile gboolean concurrent_collection_in_progress = FALSE;
 441
 442 /* objects that are ready to be finalized */
 443 static FinalizeReadyEntry *fin_ready_list = NULL;
 444 static FinalizeReadyEntry *critical_fin_list = NULL;
 445
 446 static EphemeronLinkNode *ephemeron_list;
 447
 448 /* registered roots: the key to the hash is the root start address */
 449 /*
 450  * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
 451  */
 452 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
 453         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 454         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 455         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
 456 };
 457 static mword roots_size = 0; /* amount of memory in the root set */
 458
 459 #define GC_ROOT_NUM 32
 460 typedef struct {
 461         int count;              /* must be the first field */
 462         void *objects [GC_ROOT_NUM];
 463         int root_types [GC_ROOT_NUM];
 464         uintptr_t extra_info [GC_ROOT_NUM];
 465 } GCRootReport;
 466
 467 static void
 468 notify_gc_roots (GCRootReport *report)
 469 {
 470         if (!report->count)
 471                 return;
 472         mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
 473         report->count = 0;
 474 }
 475
 476 static void
 477 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
 478 {
 479         if (report->count == GC_ROOT_NUM)
 480                 notify_gc_roots (report);
 481         report->objects [report->count] = object;
 482         report->root_types [report->count] = rtype;
 483         report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
 484 }
 485
 486 MonoNativeTlsKey thread_info_key;
 487
 488 #ifdef HAVE_KW_THREAD
 489 __thread SgenThreadInfo *sgen_thread_info;
 490 __thread char *stack_end;
 491 #endif
 492
 493 /* The size of a TLAB */
 494 /* The bigger the value, the less often we have to go to the slow path to allocate a new
 495  * one, but the more space is wasted by threads not allocating much memory.
 496  * FIXME: Tune this.
 497  * FIXME: Make this self-tuning for each thread.
 498  */
 499 guint32 tlab_size = (1024 * 4);
 500
 501 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
 502
 503 /* Functions supplied by the runtime to be called by the GC */
 504 static MonoGCCallbacks gc_callbacks;
 505
 506 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
 507 #define ALLOC_ALIGN_BITS        SGEN_ALLOC_ALIGN_BITS
 508
 509 #define ALIGN_UP                SGEN_ALIGN_UP
 510
 511 #define MOVED_OBJECTS_NUM 64
 512 static void *moved_objects [MOVED_OBJECTS_NUM];
 513 static int moved_objects_idx = 0;
 514
 515 /* Vtable of the objects used to fill out nursery fragments before a collection */
 516 static MonoVTable *array_fill_vtable;
 517
 518 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
 519 MonoNativeThreadId main_gc_thread = NULL;
 520 #endif
 521
 522 /*Object was pinned during the current collection*/
 523 static mword objects_pinned;
 524
 525 /*
 526  * ######################################################################
 527  * ########  Macros and function declarations.
 528  * ######################################################################
 529  */
 530
 531 inline static void*
 532 align_pointer (void *ptr)
 533 {
 534         mword p = (mword)ptr;
 535         p += sizeof (gpointer) - 1;
 536         p &= ~ (sizeof (gpointer) - 1);
 537         return (void*)p;
 538 }
 539
 540 typedef SgenGrayQueue GrayQueue;
 541
 542 /* forward declarations */
 543 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
 544 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
 545 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
 546 static void report_finalizer_roots (void);
 547 static void report_registered_roots (void);
 548
 549 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
 550 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
 551 static void finish_gray_stack (int generation, GrayQueue *queue);
 552
 553 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
 554
 555
 556 static void init_stats (void);
 557
 558 static int mark_ephemerons_in_range (ScanCopyContext ctx);
 559 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
 560 static void null_ephemerons_for_domain (MonoDomain *domain);
 561
 562 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
 563
 564 SgenObjectOperations current_object_ops;
 565 SgenMajorCollector major_collector;
 566 SgenMinorCollector sgen_minor_collector;
 567 static GrayQueue gray_queue;
 568
 569 static SgenRemeberedSet remset;
 570
 571 /* The gray queue to use from the main collection thread. */
 572 #define WORKERS_DISTRIBUTE_GRAY_QUEUE   (&gray_queue)
 573
 574 /*
 575  * The gray queue a worker job must use.  If we're not parallel or
 576  * concurrent, we use the main gray queue.
 577  */
 578 static SgenGrayQueue*
 579 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
 580 {
 581         return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
 582 }
 583
 584 static void
 585 gray_queue_redirect (SgenGrayQueue *queue)
 586 {
 587         gboolean wake = FALSE;
 588
 589
 590         for (;;) {
 591                 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
 592                 if (!section)
 593                         break;
 594                 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
 595                 wake = TRUE;
 596         }
 597
 598         if (wake) {
 599                 g_assert (concurrent_collection_in_progress ||
 600                                 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
 601                 if (sgen_workers_have_started ()) {
 602                         sgen_workers_wake_up_all ();
 603                 } else {
 604                         if (concurrent_collection_in_progress)
 605                                 g_assert (current_collection_generation == -1);
 606                 }
 607         }
 608 }
 609
 610 static gboolean
 611 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
 612 {
 613         MonoObject *o = (MonoObject*)(obj);
 614         MonoObject *ref = (MonoObject*)*(ptr);
 615         int offset = (char*)(ptr) - (char*)o;
 616
 617         if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
 618                 return TRUE;
 619         if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
 620                 return TRUE;
 621
 622 #ifndef DISABLE_REMOTING
 623         if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
 624                         offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
 625                 return TRUE;
 626 #endif
 627         /* Thread.cached_culture_info */
 628         if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
 629                         !strcmp (ref->vtable->klass->name, "CultureInfo") &&
 630                         !strcmp(o->vtable->klass->name_space, "System") &&
 631                         !strcmp(o->vtable->klass->name, "Object[]"))
 632                 return TRUE;
 633         /*
 634          *  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
 635          * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
 636          * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
 637          * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
 638          * 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
 639          * 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
 640          * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
 641          * 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
 642          * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
 643          */
 644         if (!strcmp (ref->vtable->klass->name_space, "System") &&
 645                         !strcmp (ref->vtable->klass->name, "Byte[]") &&
 646                         !strcmp (o->vtable->klass->name_space, "System.IO") &&
 647                         !strcmp (o->vtable->klass->name, "MemoryStream"))
 648                 return TRUE;
 649         /* append_job() in threadpool.c */
 650         if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
 651                         !strcmp (ref->vtable->klass->name, "AsyncResult") &&
 652                         !strcmp (o->vtable->klass->name_space, "System") &&
 653                         !strcmp (o->vtable->klass->name, "Object[]") &&
 654                         mono_thread_pool_is_queue_array ((MonoArray*) o))
 655                 return TRUE;
 656         return FALSE;
 657 }
 658
 659 static void
 660 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
 661 {
 662         MonoObject *o = (MonoObject*)(obj);
 663         MonoObject *ref = (MonoObject*)*(ptr);
 664         int offset = (char*)(ptr) - (char*)o;
 665         MonoClass *class;
 666         MonoClassField *field;
 667         char *str;
 668
 669         if (!ref || ref->vtable->domain == domain)
 670                 return;
 671         if (is_xdomain_ref_allowed (ptr, obj, domain))
 672                 return;
 673
 674         field = NULL;
 675         for (class = o->vtable->klass; class; class = class->parent) {
 676                 int i;
 677
 678                 for (i = 0; i < class->field.count; ++i) {
 679                         if (class->fields[i].offset == offset) {
 680                                 field = &class->fields[i];
 681                                 break;
 682                         }
 683                 }
 684                 if (field)
 685                         break;
 686         }
 687
 688         if (ref->vtable->klass == mono_defaults.string_class)
 689                 str = mono_string_to_utf8 ((MonoString*)ref);
 690         else
 691                 str = NULL;
 692         g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s)  -  pointed to by:\n",
 693                         o, o->vtable->klass->name_space, o->vtable->klass->name,
 694                         offset, field ? field->name : "",
 695                         ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
 696         mono_gc_scan_for_specific_ref (o, TRUE);
 697         if (str)
 698                 g_free (str);
 699 }
 700
 701 #undef HANDLE_PTR
 702 #define HANDLE_PTR(ptr,obj)     check_reference_for_xdomain ((ptr), (obj), domain)
 703
 704 static void
 705 scan_object_for_xdomain_refs (char *start, mword size, void *data)
 706 {
 707         MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
 708
 709         #include "sgen-scan-object.h"
 710 }
 711
 712 static gboolean scan_object_for_specific_ref_precise = TRUE;
 713
 714 #undef HANDLE_PTR
 715 #define HANDLE_PTR(ptr,obj) do {                \
 716         if ((MonoObject*)*(ptr) == key) {       \
 717         g_print ("found ref to %p in object %p (%s) at offset %td\n",   \
 718                         key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
 719         }                                                               \
 720         } while (0)
 721
 722 static void
 723 scan_object_for_specific_ref (char *start, MonoObject *key)
 724 {
 725         char *forwarded;
 726
 727         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
 728                 start = forwarded;
 729
 730         if (scan_object_for_specific_ref_precise) {
 731                 #include "sgen-scan-object.h"
 732         } else {
 733                 mword *words = (mword*)start;
 734                 size_t size = safe_object_get_size ((MonoObject*)start);
 735                 int i;
 736                 for (i = 0; i < size / sizeof (mword); ++i) {
 737                         if (words [i] == (mword)key) {
 738                                 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
 739                                                 key, start, safe_name (start), i * sizeof (mword));
 740                         }
 741                 }
 742         }
 743 }
 744
 745 void
 746 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
 747 {
 748         while (start < end) {
 749                 size_t size;
 750                 char *obj;
 751
 752                 if (!*(void**)start) {
 753                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
 754                         continue;
 755                 }
 756
 757                 if (allow_flags) {
 758                         if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
 759                                 obj = start;
 760                 } else {
 761                         obj = start;
 762                 }
 763
 764                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
 765
 766                 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
 767                         callback (obj, size, data);
 768
 769                 start += size;
 770         }
 771 }
 772
 773 static void
 774 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
 775 {
 776         scan_object_for_specific_ref (obj, key);
 777 }
 778
 779 static void
 780 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
 781 {
 782         if (key != obj)
 783                 return;
 784         g_print ("found ref to %p in root record %p\n", key, root);
 785 }
 786
 787 static MonoObject *check_key = NULL;
 788 static RootRecord *check_root = NULL;
 789
 790 static void
 791 check_root_obj_specific_ref_from_marker (void **obj)
 792 {
 793         check_root_obj_specific_ref (check_root, check_key, *obj);
 794 }
 795
 796 static void
 797 scan_roots_for_specific_ref (MonoObject *key, int root_type)
 798 {
 799         void **start_root;
 800         RootRecord *root;
 801         check_key = key;
 802
 803         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 804                 mword desc = root->root_desc;
 805
 806                 check_root = root;
 807
 808                 switch (desc & ROOT_DESC_TYPE_MASK) {
 809                 case ROOT_DESC_BITMAP:
 810                         desc >>= ROOT_DESC_TYPE_SHIFT;
 811                         while (desc) {
 812                                 if (desc & 1)
 813                                         check_root_obj_specific_ref (root, key, *start_root);
 814                                 desc >>= 1;
 815                                 start_root++;
 816                         }
 817                         return;
 818                 case ROOT_DESC_COMPLEX: {
 819                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 820                         int bwords = (*bitmap_data) - 1;
 821                         void **start_run = start_root;
 822                         bitmap_data++;
 823                         while (bwords-- > 0) {
 824                                 gsize bmap = *bitmap_data++;
 825                                 void **objptr = start_run;
 826                                 while (bmap) {
 827                                         if (bmap & 1)
 828                                                 check_root_obj_specific_ref (root, key, *objptr);
 829                                         bmap >>= 1;
 830                                         ++objptr;
 831                                 }
 832                                 start_run += GC_BITS_PER_WORD;
 833                         }
 834                         break;
 835                 }
 836                 case ROOT_DESC_USER: {
 837                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 838                         marker (start_root, check_root_obj_specific_ref_from_marker);
 839                         break;
 840                 }
 841                 case ROOT_DESC_RUN_LEN:
 842                         g_assert_not_reached ();
 843                 default:
 844                         g_assert_not_reached ();
 845                 }
 846         } SGEN_HASH_TABLE_FOREACH_END;
 847
 848         check_key = NULL;
 849         check_root = NULL;
 850 }
 851
 852 void
 853 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
 854 {
 855         void **ptr;
 856         RootRecord *root;
 857
 858         scan_object_for_specific_ref_precise = precise;
 859
 860         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 861                         (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
 862
 863         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 864
 865         sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 866
 867         scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
 868         scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
 869
 870         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
 871                 while (ptr < (void**)root->end_root) {
 872                         check_root_obj_specific_ref (root, *ptr, key);
 873                         ++ptr;
 874                 }
 875         } SGEN_HASH_TABLE_FOREACH_END;
 876 }
 877
 878 static gboolean
 879 need_remove_object_for_domain (char *start, MonoDomain *domain)
 880 {
 881         if (mono_object_domain (start) == domain) {
 882                 SGEN_LOG (4, "Need to cleanup object %p", start);
 883                 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
 884                 return TRUE;
 885         }
 886         return FALSE;
 887 }
 888
 889 static void
 890 process_object_for_domain_clearing (char *start, MonoDomain *domain)
 891 {
 892         GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
 893         if (vt->klass == mono_defaults.internal_thread_class)
 894                 g_assert (mono_object_domain (start) == mono_get_root_domain ());
 895         /* The object could be a proxy for an object in the domain
 896            we're deleting. */
 897 #ifndef DISABLE_REMOTING
 898         if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
 899                 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
 900
 901                 /* The server could already have been zeroed out, so
 902                    we need to check for that, too. */
 903                 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
 904                         SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
 905                         ((MonoRealProxy*)start)->unwrapped_server = NULL;
 906                 }
 907         }
 908 #endif
 909 }
 910
 911 static MonoDomain *check_domain = NULL;
 912
 913 static void
 914 check_obj_not_in_domain (void **o)
 915 {
 916         g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
 917 }
 918
 919 static void
 920 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
 921 {
 922         void **start_root;
 923         RootRecord *root;
 924         check_domain = domain;
 925         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 926                 mword desc = root->root_desc;
 927
 928                 /* The MonoDomain struct is allowed to hold
 929                    references to objects in its own domain. */
 930                 if (start_root == (void**)domain)
 931                         continue;
 932
 933                 switch (desc & ROOT_DESC_TYPE_MASK) {
 934                 case ROOT_DESC_BITMAP:
 935                         desc >>= ROOT_DESC_TYPE_SHIFT;
 936                         while (desc) {
 937                                 if ((desc & 1) && *start_root)
 938                                         check_obj_not_in_domain (*start_root);
 939                                 desc >>= 1;
 940                                 start_root++;
 941                         }
 942                         break;
 943                 case ROOT_DESC_COMPLEX: {
 944                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 945                         int bwords = (*bitmap_data) - 1;
 946                         void **start_run = start_root;
 947                         bitmap_data++;
 948                         while (bwords-- > 0) {
 949                                 gsize bmap = *bitmap_data++;
 950                                 void **objptr = start_run;
 951                                 while (bmap) {
 952                                         if ((bmap & 1) && *objptr)
 953                                                 check_obj_not_in_domain (*objptr);
 954                                         bmap >>= 1;
 955                                         ++objptr;
 956                                 }
 957                                 start_run += GC_BITS_PER_WORD;
 958                         }
 959                         break;
 960                 }
 961                 case ROOT_DESC_USER: {
 962                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 963                         marker (start_root, check_obj_not_in_domain);
 964                         break;
 965                 }
 966                 case ROOT_DESC_RUN_LEN:
 967                         g_assert_not_reached ();
 968                 default:
 969                         g_assert_not_reached ();
 970                 }
 971         } SGEN_HASH_TABLE_FOREACH_END;
 972
 973         check_domain = NULL;
 974 }
 975
 976 static void
 977 check_for_xdomain_refs (void)
 978 {
 979         LOSObject *bigobj;
 980
 981         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 982                         (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
 983
 984         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
 985
 986         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
 987                 scan_object_for_xdomain_refs (bigobj->data, sgen_los_object_size (bigobj), NULL);
 988 }
 989
 990 static gboolean
 991 clear_domain_process_object (char *obj, MonoDomain *domain)
 992 {
 993         gboolean remove;
 994
 995         process_object_for_domain_clearing (obj, domain);
 996         remove = need_remove_object_for_domain (obj, domain);
 997
 998         if (remove && ((MonoObject*)obj)->synchronisation) {
 999                 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
1000                 if (dislink)
1001                         sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
1002         }
1003
1004         return remove;
1005 }
1006
1007 static void
1008 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1009 {
1010         if (clear_domain_process_object (obj, domain))
1011                 memset (obj, 0, size);
1012 }
1013
1014 static void
1015 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1016 {
1017         clear_domain_process_object (obj, domain);
1018 }
1019
1020 static void
1021 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1022 {
1023         if (need_remove_object_for_domain (obj, domain))
1024                 major_collector.free_non_pinned_object (obj, size);
1025 }
1026
1027 static void
1028 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1029 {
1030         if (need_remove_object_for_domain (obj, domain))
1031                 major_collector.free_pinned_object (obj, size);
1032 }
1033
1034 /*
1035  * When appdomains are unloaded we can easily remove objects that have finalizers,
1036  * but all the others could still be present in random places on the heap.
1037  * We need a sweep to get rid of them even though it's going to be costly
1038  * with big heaps.
1039  * The reason we need to remove them is because we access the vtable and class
1040  * structures to know the object size and the reference bitmap: once the domain is
1041  * unloaded the point to random memory.
1042  */
1043 void
1044 mono_gc_clear_domain (MonoDomain * domain)
1045 {
1046         LOSObject *bigobj, *prev;
1047         int i;
1048
1049         LOCK_GC;
1050
1051         binary_protocol_domain_unload_begin (domain);
1052
1053         sgen_stop_world (0);
1054
1055         if (concurrent_collection_in_progress)
1056                 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
1057         g_assert (!concurrent_collection_in_progress);
1058
1059         sgen_process_fin_stage_entries ();
1060         sgen_process_dislink_stage_entries ();
1061
1062         sgen_clear_nursery_fragments ();
1063
1064         if (xdomain_checks && domain != mono_get_root_domain ()) {
1065                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1066                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1067                 check_for_xdomain_refs ();
1068         }
1069
1070         /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1071         to memory returned to the OS.*/
1072         null_ephemerons_for_domain (domain);
1073
1074         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1075                 sgen_null_links_for_domain (domain, i);
1076
1077         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1078                 sgen_remove_finalizers_for_domain (domain, i);
1079
1080         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1081                         (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1082
1083         /* We need two passes over major and large objects because
1084            freeing such objects might give their memory back to the OS
1085            (in the case of large objects) or obliterate its vtable
1086            (pinned objects with major-copying or pinned and non-pinned
1087            objects with major-mark&sweep), but we might need to
1088            dereference a pointer from an object to another object if
1089            the first object is a proxy. */
1090         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1091         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1092                 clear_domain_process_object (bigobj->data, domain);
1093
1094         prev = NULL;
1095         for (bigobj = los_object_list; bigobj;) {
1096                 if (need_remove_object_for_domain (bigobj->data, domain)) {
1097                         LOSObject *to_free = bigobj;
1098                         if (prev)
1099                                 prev->next = bigobj->next;
1100                         else
1101                                 los_object_list = bigobj->next;
1102                         bigobj = bigobj->next;
1103                         SGEN_LOG (4, "Freeing large object %p", bigobj->data);
1104                         sgen_los_free_object (to_free);
1105                         continue;
1106                 }
1107                 prev = bigobj;
1108                 bigobj = bigobj->next;
1109         }
1110         major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1111         major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1112
1113         if (domain == mono_get_root_domain ()) {
1114                 if (G_UNLIKELY (do_pin_stats))
1115                         sgen_pin_stats_print_class_stats ();
1116                 sgen_object_layout_dump (stdout);
1117         }
1118
1119         sgen_restart_world (0, NULL);
1120
1121         binary_protocol_domain_unload_end (domain);
1122
1123         UNLOCK_GC;
1124 }
1125
1126 /*
1127  * sgen_add_to_global_remset:
1128  *
1129  *   The global remset contains locations which point into newspace after
1130  * a minor collection. This can happen if the objects they point to are pinned.
1131  *
1132  * LOCKING: If called from a parallel collector, the global remset
1133  * lock must be held.  For serial collectors that is not necessary.
1134  */
1135 void
1136 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
1137 {
1138         SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
1139
1140         HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
1141
1142         if (!major_collector.is_concurrent) {
1143                 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
1144         } else {
1145                 if (current_collection_generation == -1)
1146                         SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
1147         }
1148
1149         if (!object_is_pinned (obj))
1150                 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");
1151         else if (sgen_cement_lookup_or_register (obj))
1152                 return;
1153
1154         remset.record_pointer (ptr);
1155
1156         if (G_UNLIKELY (do_pin_stats))
1157                 sgen_pin_stats_register_global_remset (obj);
1158
1159         SGEN_LOG (8, "Adding global remset for %p", ptr);
1160         binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
1161
1162
1163 #ifdef ENABLE_DTRACE
1164         if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
1165                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
1166                 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
1167                                 vt->klass->name_space, vt->klass->name);
1168         }
1169 #endif
1170 }
1171
1172 /*
1173  * sgen_drain_gray_stack:
1174  *
1175  *   Scan objects in the gray stack until the stack is empty. This should be called
1176  * frequently after each object is copied, to achieve better locality and cache
1177  * usage.
1178  */
1179 gboolean
1180 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
1181 {
1182         char *obj;
1183         ScanObjectFunc scan_func = ctx.scan_func;
1184         GrayQueue *queue = ctx.queue;
1185
1186         if (max_objs == -1) {
1187                 for (;;) {
1188                         GRAY_OBJECT_DEQUEUE (queue, obj);
1189                         if (!obj)
1190                                 return TRUE;
1191                         SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1192                         scan_func (obj, queue);
1193                 }
1194         } else {
1195                 int i;
1196
1197                 do {
1198                         for (i = 0; i != max_objs; ++i) {
1199                                 GRAY_OBJECT_DEQUEUE (queue, obj);
1200                                 if (!obj)
1201                                         return TRUE;
1202                                 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1203                                 scan_func (obj, queue);
1204                         }
1205                 } while (max_objs < 0);
1206                 return FALSE;
1207         }
1208 }
1209
1210 /*
1211  * Addresses from start to end are already sorted. This function finds
1212  * the object header for each address and pins the object. The
1213  * addresses must be inside the passed section.  The (start of the)
1214  * address array is overwritten with the addresses of the actually
1215  * pinned objects.  Return the number of pinned objects.
1216  */
1217 static int
1218 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1219 {
1220         void *last = NULL;
1221         int count = 0;
1222         void *search_start;
1223         void *last_obj = NULL;
1224         size_t last_obj_size = 0;
1225         void *addr;
1226         int idx;
1227         void **definitely_pinned = start;
1228         ScanObjectFunc scan_func = ctx.scan_func;
1229         SgenGrayQueue *queue = ctx.queue;
1230
1231         sgen_nursery_allocator_prepare_for_pinning ();
1232
1233         while (start < end) {
1234                 addr = *start;
1235                 /* the range check should be reduntant */
1236                 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1237                         SGEN_LOG (5, "Considering pinning addr %p", addr);
1238                         /* multiple pointers to the same object */
1239                         if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1240                                 start++;
1241                                 continue;
1242                         }
1243                         idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1244                         g_assert (idx < section->num_scan_start);
1245                         search_start = (void*)section->scan_starts [idx];
1246                         if (!search_start || search_start > addr) {
1247                                 while (idx) {
1248                                         --idx;
1249                                         search_start = section->scan_starts [idx];
1250                                         if (search_start && search_start <= addr)
1251                                                 break;
1252                                 }
1253                                 if (!search_start || search_start > addr)
1254                                         search_start = start_nursery;
1255                         }
1256                         if (search_start < last_obj)
1257                                 search_start = (char*)last_obj + last_obj_size;
1258                         /* now addr should be in an object a short distance from search_start
1259                          * Note that search_start must point to zeroed mem or point to an object.
1260                          */
1261
1262                         do {
1263                                 if (!*(void**)search_start) {
1264                                         /* Consistency check */
1265                                         /*
1266                                         for (frag = nursery_fragments; frag; frag = frag->next) {
1267                                                 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1268                                                         g_assert_not_reached ();
1269                                         }
1270                                         */
1271
1272                                         search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1273                                         continue;
1274                                 }
1275                                 last_obj = search_start;
1276                                 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1277
1278                                 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1279                                         /* Marks the beginning of a nursery fragment, skip */
1280                                 } else {
1281                                         SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
1282                                         if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1283                                                 if (scan_func) {
1284                                                         scan_func (search_start, queue);
1285                                                 } else {
1286                                                         SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1287                                                                         search_start, *(void**)search_start, safe_name (search_start), count);
1288                                                         binary_protocol_pin (search_start,
1289                                                                         (gpointer)LOAD_VTABLE (search_start),
1290                                                                         safe_object_get_size (search_start));
1291
1292 #ifdef ENABLE_DTRACE
1293                                                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1294                                                                 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
1295                                                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
1296                                                                 MONO_GC_OBJ_PINNED ((mword)search_start,
1297                                                                                 sgen_safe_object_get_size (search_start),
1298                                                                                 vt->klass->name_space, vt->klass->name, gen);
1299                                                         }
1300 #endif
1301
1302                                                         pin_object (search_start);
1303                                                         GRAY_OBJECT_ENQUEUE (queue, search_start);
1304                                                         if (G_UNLIKELY (do_pin_stats))
1305                                                                 sgen_pin_stats_register_object (search_start, last_obj_size);
1306                                                         definitely_pinned [count] = search_start;
1307                                                         count++;
1308                                                 }
1309                                                 break;
1310                                         }
1311                                 }
1312                                 /* skip to the next object */
1313                                 search_start = (void*)((char*)search_start + last_obj_size);
1314                         } while (search_start <= addr);
1315                         /* we either pinned the correct object or we ignored the addr because
1316                          * it points to unused zeroed memory.
1317                          */
1318                         last = addr;
1319                 }
1320                 start++;
1321         }
1322         //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1323         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1324                 GCRootReport report;
1325                 report.count = 0;
1326                 for (idx = 0; idx < count; ++idx)
1327                         add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1328                 notify_gc_roots (&report);
1329         }
1330         stat_pinned_objects += count;
1331         return count;
1332 }
1333
1334 void
1335 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1336 {
1337         int num_entries = section->pin_queue_num_entries;
1338         if (num_entries) {
1339                 void **start = section->pin_queue_start;
1340                 int reduced_to;
1341                 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1342                                 section->data, section->next_data, ctx);
1343                 section->pin_queue_num_entries = reduced_to;
1344                 if (!reduced_to)
1345                         section->pin_queue_start = NULL;
1346         }
1347 }
1348
1349
1350 void
1351 sgen_pin_object (void *object, GrayQueue *queue)
1352 {
1353         g_assert (!concurrent_collection_in_progress);
1354
1355         if (sgen_collection_is_parallel ()) {
1356                 LOCK_PIN_QUEUE;
1357                 /*object arrives pinned*/
1358                 sgen_pin_stage_ptr (object);
1359                 ++objects_pinned ;
1360                 UNLOCK_PIN_QUEUE;
1361         } else {
1362                 SGEN_PIN_OBJECT (object);
1363                 sgen_pin_stage_ptr (object);
1364                 ++objects_pinned;
1365                 if (G_UNLIKELY (do_pin_stats))
1366                         sgen_pin_stats_register_object (object, safe_object_get_size (object));
1367         }
1368         GRAY_OBJECT_ENQUEUE (queue, object);
1369         binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1370
1371 #ifdef ENABLE_DTRACE
1372         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1373                 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1374                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1375                 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1376         }
1377 #endif
1378 }
1379
1380 void
1381 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1382 {
1383         for (;;) {
1384                 mword vtable_word;
1385                 gboolean major_pinned = FALSE;
1386
1387                 if (sgen_ptr_in_nursery (obj)) {
1388                         if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1389                                 sgen_pin_object (obj, queue);
1390                                 break;
1391                         }
1392                 } else {
1393                         major_collector.pin_major_object (obj, queue);
1394                         major_pinned = TRUE;
1395                 }
1396
1397                 vtable_word = *(mword*)obj;
1398                 /*someone else forwarded it, update the pointer and bail out*/
1399                 if (vtable_word & SGEN_FORWARDED_BIT) {
1400                         *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1401                         break;
1402                 }
1403
1404                 /*someone pinned it, nothing to do.*/
1405                 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1406                         break;
1407         }
1408 }
1409
1410 /* Sort the addresses in array in increasing order.
1411  * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1412  */
1413 void
1414 sgen_sort_addresses (void **array, int size)
1415 {
1416         int i;
1417         void *tmp;
1418
1419         for (i = 1; i < size; ++i) {
1420                 int child = i;
1421                 while (child > 0) {
1422                         int parent = (child - 1) / 2;
1423
1424                         if (array [parent] >= array [child])
1425                                 break;
1426
1427                         tmp = array [parent];
1428                         array [parent] = array [child];
1429                         array [child] = tmp;
1430
1431                         child = parent;
1432                 }
1433         }
1434
1435         for (i = size - 1; i > 0; --i) {
1436                 int end, root;
1437                 tmp = array [i];
1438                 array [i] = array [0];
1439                 array [0] = tmp;
1440
1441                 end = i - 1;
1442                 root = 0;
1443
1444                 while (root * 2 + 1 <= end) {
1445                         int child = root * 2 + 1;
1446
1447                         if (child < end && array [child] < array [child + 1])
1448                                 ++child;
1449                         if (array [root] >= array [child])
1450                                 break;
1451
1452                         tmp = array [root];
1453                         array [root] = array [child];
1454                         array [child] = tmp;
1455
1456                         root = child;
1457                 }
1458         }
1459 }
1460
1461 /*
1462  * Scan the memory between start and end and queue values which could be pointers
1463  * to the area between start_nursery and end_nursery for later consideration.
1464  * Typically used for thread stacks.
1465  */
1466 static void
1467 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1468 {
1469         int count = 0;
1470
1471 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1472         VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1473 #endif
1474
1475         while (start < end) {
1476                 if (*start >= start_nursery && *start < end_nursery) {
1477                         /*
1478                          * *start can point to the middle of an object
1479                          * note: should we handle pointing at the end of an object?
1480                          * pinning in C# code disallows pointing at the end of an object
1481                          * but there is some small chance that an optimizing C compiler
1482                          * may keep the only reference to an object by pointing
1483                          * at the end of it. We ignore this small chance for now.
1484                          * Pointers to the end of an object are indistinguishable
1485                          * from pointers to the start of the next object in memory
1486                          * so if we allow that we'd need to pin two objects...
1487                          * We queue the pointer in an array, the
1488                          * array will then be sorted and uniqued. This way
1489                          * we can coalesce several pinning pointers and it should
1490                          * be faster since we'd do a memory scan with increasing
1491                          * addresses. Note: we can align the address to the allocation
1492                          * alignment, so the unique process is more effective.
1493                          */
1494                         mword addr = (mword)*start;
1495                         addr &= ~(ALLOC_ALIGN - 1);
1496                         if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1497                                 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1498                                 sgen_pin_stage_ptr ((void*)addr);
1499                                 count++;
1500                         }
1501                         if (G_UNLIKELY (do_pin_stats)) {
1502                                 if (ptr_in_nursery ((void*)addr))
1503                                         sgen_pin_stats_register_address ((char*)addr, pin_type);
1504                         }
1505                 }
1506                 start++;
1507         }
1508         if (count)
1509                 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1510 }
1511
1512 /*
1513  * The first thing we do in a collection is to identify pinned objects.
1514  * This function considers all the areas of memory that need to be
1515  * conservatively scanned.
1516  */
1517 static void
1518 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1519 {
1520         void **start_root;
1521         RootRecord *root;
1522         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);
1523         /* objects pinned from the API are inside these roots */
1524         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1525                 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1526                 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1527         } SGEN_HASH_TABLE_FOREACH_END;
1528         /* now deal with the thread stacks
1529          * in the future we should be able to conservatively scan only:
1530          * *) the cpu registers
1531          * *) the unmanaged stack frames
1532          * *) the _last_ managed stack frame
1533          * *) pointers slots in managed frames
1534          */
1535         scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1536 }
1537
1538 static void
1539 unpin_objects_from_queue (SgenGrayQueue *queue)
1540 {
1541         for (;;) {
1542                 char *addr;
1543                 GRAY_OBJECT_DEQUEUE (queue, addr);
1544                 if (!addr)
1545                         break;
1546                 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1547                 SGEN_UNPIN_OBJECT (addr);
1548         }
1549 }
1550
1551 typedef struct {
1552         CopyOrMarkObjectFunc func;
1553         GrayQueue *queue;
1554 } UserCopyOrMarkData;
1555
1556 static MonoNativeTlsKey user_copy_or_mark_key;
1557
1558 static void
1559 init_user_copy_or_mark_key (void)
1560 {
1561         mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1562 }
1563
1564 static void
1565 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1566 {
1567         mono_native_tls_set_value (user_copy_or_mark_key, data);
1568 }
1569
1570 static void
1571 single_arg_user_copy_or_mark (void **obj)
1572 {
1573         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1574
1575         data->func (obj, data->queue);
1576 }
1577
1578 /*
1579  * The memory area from start_root to end_root contains pointers to objects.
1580  * Their position is precisely described by @desc (this means that the pointer
1581  * can be either NULL or the pointer to the start of an object).
1582  * This functions copies them to to_space updates them.
1583  *
1584  * This function is not thread-safe!
1585  */
1586 static void
1587 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1588 {
1589         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1590         SgenGrayQueue *queue = ctx.queue;
1591
1592         switch (desc & ROOT_DESC_TYPE_MASK) {
1593         case ROOT_DESC_BITMAP:
1594                 desc >>= ROOT_DESC_TYPE_SHIFT;
1595                 while (desc) {
1596                         if ((desc & 1) && *start_root) {
1597                                 copy_func (start_root, queue);
1598                                 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1599                                 sgen_drain_gray_stack (-1, ctx);
1600                         }
1601                         desc >>= 1;
1602                         start_root++;
1603                 }
1604                 return;
1605         case ROOT_DESC_COMPLEX: {
1606                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1607                 int bwords = (*bitmap_data) - 1;
1608                 void **start_run = start_root;
1609                 bitmap_data++;
1610                 while (bwords-- > 0) {
1611                         gsize bmap = *bitmap_data++;
1612                         void **objptr = start_run;
1613                         while (bmap) {
1614                                 if ((bmap & 1) && *objptr) {
1615                                         copy_func (objptr, queue);
1616                                         SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1617                                         sgen_drain_gray_stack (-1, ctx);
1618                                 }
1619                                 bmap >>= 1;
1620                                 ++objptr;
1621                         }
1622                         start_run += GC_BITS_PER_WORD;
1623                 }
1624                 break;
1625         }
1626         case ROOT_DESC_USER: {
1627                 UserCopyOrMarkData data = { copy_func, queue };
1628                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1629                 set_user_copy_or_mark_data (&data);
1630                 marker (start_root, single_arg_user_copy_or_mark);
1631                 set_user_copy_or_mark_data (NULL);
1632                 break;
1633         }
1634         case ROOT_DESC_RUN_LEN:
1635                 g_assert_not_reached ();
1636         default:
1637                 g_assert_not_reached ();
1638         }
1639 }
1640
1641 static void
1642 reset_heap_boundaries (void)
1643 {
1644         lowest_heap_address = ~(mword)0;
1645         highest_heap_address = 0;
1646 }
1647
1648 void
1649 sgen_update_heap_boundaries (mword low, mword high)
1650 {
1651         mword old;
1652
1653         do {
1654                 old = lowest_heap_address;
1655                 if (low >= old)
1656                         break;
1657         } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1658
1659         do {
1660                 old = highest_heap_address;
1661                 if (high <= old)
1662                         break;
1663         } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1664 }
1665
1666 /*
1667  * Allocate and setup the data structures needed to be able to allocate objects
1668  * in the nursery. The nursery is stored in nursery_section.
1669  */
1670 static void
1671 alloc_nursery (void)
1672 {
1673         GCMemSection *section;
1674         char *data;
1675         int scan_starts;
1676         int alloc_size;
1677
1678         if (nursery_section)
1679                 return;
1680         SGEN_LOG (2, "Allocating nursery size: %lu", (unsigned long)sgen_nursery_size);
1681         /* later we will alloc a larger area for the nursery but only activate
1682          * what we need. The rest will be used as expansion if we have too many pinned
1683          * objects in the existing nursery.
1684          */
1685         /* FIXME: handle OOM */
1686         section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1687
1688         alloc_size = sgen_nursery_size;
1689
1690         /* If there isn't enough space even for the nursery we should simply abort. */
1691         g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1692
1693 #ifdef SGEN_ALIGN_NURSERY
1694         data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1695 #else
1696         data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1697 #endif
1698         sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1699         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 ());
1700         section->data = section->next_data = data;
1701         section->size = alloc_size;
1702         section->end_data = data + sgen_nursery_size;
1703         scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1704         section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1705         section->num_scan_start = scan_starts;
1706
1707         nursery_section = section;
1708
1709         sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1710 }
1711
1712 void*
1713 mono_gc_get_nursery (int *shift_bits, size_t *size)
1714 {
1715         *size = sgen_nursery_size;
1716 #ifdef SGEN_ALIGN_NURSERY
1717         *shift_bits = DEFAULT_NURSERY_BITS;
1718 #else
1719         *shift_bits = -1;
1720 #endif
1721         return sgen_get_nursery_start ();
1722 }
1723
1724 void
1725 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1726 {
1727         SgenThreadInfo *info = mono_thread_info_current ();
1728
1729         /* Could be called from sgen_thread_unregister () with a NULL info */
1730         if (domain) {
1731                 g_assert (info);
1732                 info->stopped_domain = domain;
1733         }
1734 }
1735
1736 gboolean
1737 mono_gc_precise_stack_mark_enabled (void)
1738 {
1739         return !conservative_stack_mark;
1740 }
1741
1742 FILE *
1743 mono_gc_get_logfile (void)
1744 {
1745         return gc_debug_file;
1746 }
1747
1748 static void
1749 report_finalizer_roots_list (FinalizeReadyEntry *list)
1750 {
1751         GCRootReport report;
1752         FinalizeReadyEntry *fin;
1753
1754         report.count = 0;
1755         for (fin = list; fin; fin = fin->next) {
1756                 if (!fin->object)
1757                         continue;
1758                 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1759         }
1760         notify_gc_roots (&report);
1761 }
1762
1763 static void
1764 report_finalizer_roots (void)
1765 {
1766         report_finalizer_roots_list (fin_ready_list);
1767         report_finalizer_roots_list (critical_fin_list);
1768 }
1769
1770 static GCRootReport *root_report;
1771
1772 static void
1773 single_arg_report_root (void **obj)
1774 {
1775         if (*obj)
1776                 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1777 }
1778
1779 static void
1780 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1781 {
1782         switch (desc & ROOT_DESC_TYPE_MASK) {
1783         case ROOT_DESC_BITMAP:
1784                 desc >>= ROOT_DESC_TYPE_SHIFT;
1785                 while (desc) {
1786                         if ((desc & 1) && *start_root) {
1787                                 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1788                         }
1789                         desc >>= 1;
1790                         start_root++;
1791                 }
1792                 return;
1793         case ROOT_DESC_COMPLEX: {
1794                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1795                 int bwords = (*bitmap_data) - 1;
1796                 void **start_run = start_root;
1797                 bitmap_data++;
1798                 while (bwords-- > 0) {
1799                         gsize bmap = *bitmap_data++;
1800                         void **objptr = start_run;
1801                         while (bmap) {
1802                                 if ((bmap & 1) && *objptr) {
1803                                         add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1804                                 }
1805                                 bmap >>= 1;
1806                                 ++objptr;
1807                         }
1808                         start_run += GC_BITS_PER_WORD;
1809                 }
1810                 break;
1811         }
1812         case ROOT_DESC_USER: {
1813                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1814                 root_report = report;
1815                 marker (start_root, single_arg_report_root);
1816                 break;
1817         }
1818         case ROOT_DESC_RUN_LEN:
1819                 g_assert_not_reached ();
1820         default:
1821                 g_assert_not_reached ();
1822         }
1823 }
1824
1825 static void
1826 report_registered_roots_by_type (int root_type)
1827 {
1828         GCRootReport report;
1829         void **start_root;
1830         RootRecord *root;
1831         report.count = 0;
1832         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1833                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1834                 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1835         } SGEN_HASH_TABLE_FOREACH_END;
1836         notify_gc_roots (&report);
1837 }
1838
1839 static void
1840 report_registered_roots (void)
1841 {
1842         report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1843         report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1844 }
1845
1846 static void
1847 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1848 {
1849         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1850         SgenGrayQueue *queue = ctx.queue;
1851         FinalizeReadyEntry *fin;
1852
1853         for (fin = list; fin; fin = fin->next) {
1854                 if (!fin->object)
1855                         continue;
1856                 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1857                 copy_func (&fin->object, queue);
1858         }
1859 }
1860
1861 static const char*
1862 generation_name (int generation)
1863 {
1864         switch (generation) {
1865         case GENERATION_NURSERY: return "nursery";
1866         case GENERATION_OLD: return "old";
1867         default: g_assert_not_reached ();
1868         }
1869 }
1870
1871 const char*
1872 sgen_generation_name (int generation)
1873 {
1874         return generation_name (generation);
1875 }
1876
1877 SgenObjectOperations *
1878 sgen_get_current_object_ops (void){
1879         return &current_object_ops;
1880 }
1881
1882
1883 static void
1884 finish_gray_stack (int generation, GrayQueue *queue)
1885 {
1886         TV_DECLARE (atv);
1887         TV_DECLARE (btv);
1888         int done_with_ephemerons, ephemeron_rounds = 0;
1889         CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1890         ScanObjectFunc scan_func = current_object_ops.scan_object;
1891         ScanCopyContext ctx = { scan_func, copy_func, queue };
1892         char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1893         char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1894
1895         /*
1896          * We copied all the reachable objects. Now it's the time to copy
1897          * the objects that were not referenced by the roots, but by the copied objects.
1898          * we built a stack of objects pointed to by gray_start: they are
1899          * additional roots and we may add more items as we go.
1900          * We loop until gray_start == gray_objects which means no more objects have
1901          * been added. Note this is iterative: no recursion is involved.
1902          * We need to walk the LO list as well in search of marked big objects
1903          * (use a flag since this is needed only on major collections). We need to loop
1904          * here as well, so keep a counter of marked LO (increasing it in copy_object).
1905          *   To achieve better cache locality and cache usage, we drain the gray stack
1906          * frequently, after each object is copied, and just finish the work here.
1907          */
1908         sgen_drain_gray_stack (-1, ctx);
1909         TV_GETTIME (atv);
1910         SGEN_LOG (2, "%s generation done", generation_name (generation));
1911
1912         /*
1913         Reset bridge data, we might have lingering data from a previous collection if this is a major
1914         collection trigged by minor overflow.
1915
1916         We must reset the gathered bridges since their original block might be evacuated due to major
1917         fragmentation in the meanwhile and the bridge code should not have to deal with that.
1918         */
1919         if (sgen_need_bridge_processing ())
1920                 sgen_bridge_reset_data ();
1921
1922         /*
1923          * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1924          * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1925          * objects that are in fact reachable.
1926          */
1927         done_with_ephemerons = 0;
1928         do {
1929                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1930                 sgen_drain_gray_stack (-1, ctx);
1931                 ++ephemeron_rounds;
1932         } while (!done_with_ephemerons);
1933
1934         sgen_scan_togglerefs (start_addr, end_addr, ctx);
1935
1936         if (sgen_need_bridge_processing ()) {
1937                 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1938                 sgen_drain_gray_stack (-1, ctx);
1939                 sgen_collect_bridge_objects (generation, ctx);
1940                 if (generation == GENERATION_OLD)
1941                         sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1942
1943                 /*
1944                 Do the first bridge step here, as the collector liveness state will become useless after that.
1945
1946                 An important optimization is to only proccess the possibly dead part of the object graph and skip
1947                 over all live objects as we transitively know everything they point must be alive too.
1948
1949                 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1950
1951                 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1952                 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1953                 be a big deal.
1954                 */
1955                 sgen_bridge_processing_stw_step ();
1956         }
1957
1958         /*
1959         Make sure we drain the gray stack before processing disappearing links and finalizers.
1960         If we don't make sure it is empty we might wrongly see a live object as dead.
1961         */
1962         sgen_drain_gray_stack (-1, ctx);
1963
1964         /*
1965         We must clear weak links that don't track resurrection before processing object ready for
1966         finalization so they can be cleared before that.
1967         */
1968         sgen_null_link_in_range (generation, TRUE, ctx);
1969         if (generation == GENERATION_OLD)
1970                 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1971
1972
1973         /* walk the finalization queue and move also the objects that need to be
1974          * finalized: use the finalized objects as new roots so the objects they depend
1975          * on are also not reclaimed. As with the roots above, only objects in the nursery
1976          * are marked/copied.
1977          */
1978         sgen_finalize_in_range (generation, ctx);
1979         if (generation == GENERATION_OLD)
1980                 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1981         /* drain the new stack that might have been created */
1982         SGEN_LOG (6, "Precise scan of gray area post fin");
1983         sgen_drain_gray_stack (-1, ctx);
1984
1985         /*
1986          * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1987          */
1988         done_with_ephemerons = 0;
1989         do {
1990                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1991                 sgen_drain_gray_stack (-1, ctx);
1992                 ++ephemeron_rounds;
1993         } while (!done_with_ephemerons);
1994
1995         /*
1996          * Clear ephemeron pairs with unreachable keys.
1997          * We pass the copy func so we can figure out if an array was promoted or not.
1998          */
1999         clear_unreachable_ephemerons (ctx);
2000
2001         TV_GETTIME (btv);
2002         SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
2003
2004         /*
2005          * handle disappearing links
2006          * Note we do this after checking the finalization queue because if an object
2007          * survives (at least long enough to be finalized) we don't clear the link.
2008          * This also deals with a possible issue with the monitor reclamation: with the Boehm
2009          * GC a finalized object my lose the monitor because it is cleared before the finalizer is
2010          * called.
2011          */
2012         g_assert (sgen_gray_object_queue_is_empty (queue));
2013         for (;;) {
2014                 sgen_null_link_in_range (generation, FALSE, ctx);
2015                 if (generation == GENERATION_OLD)
2016                         sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
2017                 if (sgen_gray_object_queue_is_empty (queue))
2018                         break;
2019                 sgen_drain_gray_stack (-1, ctx);
2020         }
2021
2022         g_assert (sgen_gray_object_queue_is_empty (queue));
2023 }
2024
2025 void
2026 sgen_check_section_scan_starts (GCMemSection *section)
2027 {
2028         int i;
2029         for (i = 0; i < section->num_scan_start; ++i) {
2030                 if (section->scan_starts [i]) {
2031                         guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2032                         g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2033                 }
2034         }
2035 }
2036
2037 static void
2038 check_scan_starts (void)
2039 {
2040         if (!do_scan_starts_check)
2041                 return;
2042         sgen_check_section_scan_starts (nursery_section);
2043         major_collector.check_scan_starts ();
2044 }
2045
2046 static void
2047 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
2048 {
2049         void **start_root;
2050         RootRecord *root;
2051         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2052                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
2053                 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
2054         } SGEN_HASH_TABLE_FOREACH_END;
2055 }
2056
2057 void
2058 sgen_dump_occupied (char *start, char *end, char *section_start)
2059 {
2060         fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2061 }
2062
2063 void
2064 sgen_dump_section (GCMemSection *section, const char *type)
2065 {
2066         char *start = section->data;
2067         char *end = section->data + section->size;
2068         char *occ_start = NULL;
2069         GCVTable *vt;
2070         char *old_start = NULL; /* just for debugging */
2071
2072         fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2073
2074         while (start < end) {
2075                 guint size;
2076                 MonoClass *class;
2077
2078                 if (!*(void**)start) {
2079                         if (occ_start) {
2080                                 sgen_dump_occupied (occ_start, start, section->data);
2081                                 occ_start = NULL;
2082                         }
2083                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2084                         continue;
2085                 }
2086                 g_assert (start < section->next_data);
2087
2088                 if (!occ_start)
2089                         occ_start = start;
2090
2091                 vt = (GCVTable*)LOAD_VTABLE (start);
2092                 class = vt->klass;
2093
2094                 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2095
2096                 /*
2097                 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2098                                 start - section->data,
2099                                 vt->klass->name_space, vt->klass->name,
2100                                 size);
2101                 */
2102
2103                 old_start = start;
2104                 start += size;
2105         }
2106         if (occ_start)
2107                 sgen_dump_occupied (occ_start, start, section->data);
2108
2109         fprintf (heap_dump_file, "</section>\n");
2110 }
2111
2112 static void
2113 dump_object (MonoObject *obj, gboolean dump_location)
2114 {
2115         static char class_name [1024];
2116
2117         MonoClass *class = mono_object_class (obj);
2118         int i, j;
2119
2120         /*
2121          * Python's XML parser is too stupid to parse angle brackets
2122          * in strings, so we just ignore them;
2123          */
2124         i = j = 0;
2125         while (class->name [i] && j < sizeof (class_name) - 1) {
2126                 if (!strchr ("<>\"", class->name [i]))
2127                         class_name [j++] = class->name [i];
2128                 ++i;
2129         }
2130         g_assert (j < sizeof (class_name));
2131         class_name [j] = 0;
2132
2133         fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2134                         class->name_space, class_name,
2135                         safe_object_get_size (obj));
2136         if (dump_location) {
2137                 const char *location;
2138                 if (ptr_in_nursery (obj))
2139                         location = "nursery";
2140                 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2141                         location = "major";
2142                 else
2143                         location = "LOS";
2144                 fprintf (heap_dump_file, " location=\"%s\"", location);
2145         }
2146         fprintf (heap_dump_file, "/>\n");
2147 }
2148
2149 static void
2150 dump_heap (const char *type, int num, const char *reason)
2151 {
2152         ObjectList *list;
2153         LOSObject *bigobj;
2154
2155         fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2156         if (reason)
2157                 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2158         fprintf (heap_dump_file, ">\n");
2159         fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2160         sgen_dump_internal_mem_usage (heap_dump_file);
2161         fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2162         /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2163         fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2164
2165         fprintf (heap_dump_file, "<pinned-objects>\n");
2166         for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2167                 dump_object (list->obj, TRUE);
2168         fprintf (heap_dump_file, "</pinned-objects>\n");
2169
2170         sgen_dump_section (nursery_section, "nursery");
2171
2172         major_collector.dump_heap (heap_dump_file);
2173
2174         fprintf (heap_dump_file, "<los>\n");
2175         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2176                 dump_object ((MonoObject*)bigobj->data, FALSE);
2177         fprintf (heap_dump_file, "</los>\n");
2178
2179         fprintf (heap_dump_file, "</collection>\n");
2180 }
2181
2182 void
2183 sgen_register_moved_object (void *obj, void *destination)
2184 {
2185         g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2186
2187         /* FIXME: handle this for parallel collector */
2188         g_assert (!sgen_collection_is_parallel ());
2189
2190         if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2191                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2192                 moved_objects_idx = 0;
2193         }
2194         moved_objects [moved_objects_idx++] = obj;
2195         moved_objects [moved_objects_idx++] = destination;
2196 }
2197
2198 static void
2199 init_stats (void)
2200 {
2201         static gboolean inited = FALSE;
2202
2203         if (inited)
2204                 return;
2205
2206         mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2207         mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2208         mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2209         mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2210         mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2211         mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2212         mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2213         mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2214
2215         mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2216         mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2217         mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2218         mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2219         mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2220         mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2221         mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2222         mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2223         mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2224         mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2225         mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2226         mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2227         mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2228
2229         mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2230
2231 #ifdef HEAVY_STATISTICS
2232         mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
2233         mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2234         mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2235         mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2236         mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2237         mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2238         mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2239         mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2240
2241         mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2242         mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2243
2244         mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2245         mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2246         mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2247         mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2248
2249         mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2250         mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2251
2252         mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2253
2254         mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2255         mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2256         mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2257         mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2258
2259         sgen_nursery_allocator_init_heavy_stats ();
2260         sgen_alloc_init_heavy_stats ();
2261 #endif
2262
2263         inited = TRUE;
2264 }
2265
2266
2267 static void
2268 reset_pinned_from_failed_allocation (void)
2269 {
2270         bytes_pinned_from_failed_allocation = 0;
2271 }
2272
2273 void
2274 sgen_set_pinned_from_failed_allocation (mword objsize)
2275 {
2276         bytes_pinned_from_failed_allocation += objsize;
2277 }
2278
2279 gboolean
2280 sgen_collection_is_parallel (void)
2281 {
2282         switch (current_collection_generation) {
2283         case GENERATION_NURSERY:
2284                 return nursery_collection_is_parallel;
2285         case GENERATION_OLD:
2286                 return major_collector.is_parallel;
2287         default:
2288                 g_error ("Invalid current generation %d", current_collection_generation);
2289         }
2290 }
2291
2292 gboolean
2293 sgen_collection_is_concurrent (void)
2294 {
2295         switch (current_collection_generation) {
2296         case GENERATION_NURSERY:
2297                 return FALSE;
2298         case GENERATION_OLD:
2299                 return concurrent_collection_in_progress;
2300         default:
2301                 g_error ("Invalid current generation %d", current_collection_generation);
2302         }
2303 }
2304
2305 gboolean
2306 sgen_concurrent_collection_in_progress (void)
2307 {
2308         return concurrent_collection_in_progress;
2309 }
2310
2311 typedef struct
2312 {
2313         char *heap_start;
2314         char *heap_end;
2315 } FinishRememberedSetScanJobData;
2316
2317 static void
2318 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2319 {
2320         FinishRememberedSetScanJobData *job_data = job_data_untyped;
2321
2322         remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2323         sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2324 }
2325
2326 typedef struct
2327 {
2328         CopyOrMarkObjectFunc copy_or_mark_func;
2329         ScanObjectFunc scan_func;
2330         char *heap_start;
2331         char *heap_end;
2332         int root_type;
2333 } ScanFromRegisteredRootsJobData;
2334
2335 static void
2336 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2337 {
2338         ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2339         ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2340                 sgen_workers_get_job_gray_queue (worker_data) };
2341
2342         scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2343         sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2344 }
2345
2346 typedef struct
2347 {
2348         char *heap_start;
2349         char *heap_end;
2350 } ScanThreadDataJobData;
2351
2352 static void
2353 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2354 {
2355         ScanThreadDataJobData *job_data = job_data_untyped;
2356
2357         scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2358                         sgen_workers_get_job_gray_queue (worker_data));
2359         sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2360 }
2361
2362 typedef struct
2363 {
2364         FinalizeReadyEntry *list;
2365 } ScanFinalizerEntriesJobData;
2366
2367 static void
2368 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2369 {
2370         ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2371         ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2372
2373         scan_finalizer_entries (job_data->list, ctx);
2374         sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2375 }
2376
2377 static void
2378 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2379 {
2380         g_assert (concurrent_collection_in_progress);
2381         major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2382 }
2383
2384 static void
2385 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2386 {
2387         g_assert (concurrent_collection_in_progress);
2388         sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2389 }
2390
2391 static void
2392 verify_scan_starts (char *start, char *end)
2393 {
2394         int i;
2395
2396         for (i = 0; i < nursery_section->num_scan_start; ++i) {
2397                 char *addr = nursery_section->scan_starts [i];
2398                 if (addr > start && addr < end)
2399                         SGEN_LOG (1, "NFC-BAD SCAN START [%d] %p for obj [%p %p]", i, addr, start, end);
2400         }
2401 }
2402
2403 static void
2404 verify_nursery (void)
2405 {
2406         char *start, *end, *cur, *hole_start;
2407
2408         if (!do_verify_nursery)
2409                 return;
2410
2411         /*This cleans up unused fragments */
2412         sgen_nursery_allocator_prepare_for_pinning ();
2413
2414         hole_start = start = cur = sgen_get_nursery_start ();
2415         end = sgen_get_nursery_end ();
2416
2417         while (cur < end) {
2418                 size_t ss, size;
2419
2420                 if (!*(void**)cur) {
2421                         cur += sizeof (void*);
2422                         continue;
2423                 }
2424
2425                 if (object_is_forwarded (cur))
2426                         SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2427                 else if (object_is_pinned (cur))
2428                         SGEN_LOG (1, "PINNED OBJ %p", cur);
2429
2430                 ss = safe_object_get_size ((MonoObject*)cur);
2431                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2432                 verify_scan_starts (cur, cur + size);
2433                 if (do_dump_nursery_content) {
2434                         if (cur > hole_start)
2435                                 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2436                         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 ());
2437                 }
2438                 cur += size;
2439                 hole_start = cur;
2440         }
2441 }
2442
2443 /*
2444  * Checks that no objects in the nursery are fowarded or pinned.  This
2445  * is a precondition to restarting the mutator while doing a
2446  * concurrent collection.  Note that we don't clear fragments because
2447  * we depend on that having happened earlier.
2448  */
2449 static void
2450 check_nursery_is_clean (void)
2451 {
2452         char *start, *end, *cur;
2453
2454         start = cur = sgen_get_nursery_start ();
2455         end = sgen_get_nursery_end ();
2456
2457         while (cur < end) {
2458                 size_t ss, size;
2459
2460                 if (!*(void**)cur) {
2461                         cur += sizeof (void*);
2462                         continue;
2463                 }
2464
2465                 g_assert (!object_is_forwarded (cur));
2466                 g_assert (!object_is_pinned (cur));
2467
2468                 ss = safe_object_get_size ((MonoObject*)cur);
2469                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2470                 verify_scan_starts (cur, cur + size);
2471
2472                 cur += size;
2473         }
2474 }
2475
2476 static void
2477 init_gray_queue (void)
2478 {
2479         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2480                 sgen_workers_init_distribute_gray_queue ();
2481                 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2482                                 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2483         } else {
2484                 sgen_gray_object_queue_init (&gray_queue, NULL);
2485         }
2486 }
2487
2488 static void
2489 pin_stage_object_callback (char *obj, size_t size, void *data)
2490 {
2491         sgen_pin_stage_ptr (obj);
2492         /* FIXME: do pin stats if enabled */
2493 }
2494
2495 /*
2496  * Collect objects in the nursery.  Returns whether to trigger a major
2497  * collection.
2498  */
2499 static gboolean
2500 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2501 {
2502         gboolean needs_major;
2503         size_t max_garbage_amount;
2504         char *nursery_next;
2505         FinishRememberedSetScanJobData *frssjd;
2506         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2507         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2508         ScanThreadDataJobData *stdjd;
2509         mword fragment_total;
2510         ScanCopyContext ctx;
2511         TV_DECLARE (all_atv);
2512         TV_DECLARE (all_btv);
2513         TV_DECLARE (atv);
2514         TV_DECLARE (btv);
2515
2516         if (disable_minor_collections)
2517                 return TRUE;
2518
2519         MONO_GC_BEGIN (GENERATION_NURSERY);
2520         binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2521
2522         verify_nursery ();
2523
2524 #ifndef DISABLE_PERFCOUNTERS
2525         mono_perfcounters->gc_collections0++;
2526 #endif
2527
2528         current_collection_generation = GENERATION_NURSERY;
2529         if (sgen_collection_is_parallel ())
2530                 current_object_ops = sgen_minor_collector.parallel_ops;
2531         else
2532                 current_object_ops = sgen_minor_collector.serial_ops;
2533
2534         reset_pinned_from_failed_allocation ();
2535
2536         check_scan_starts ();
2537
2538         sgen_nursery_alloc_prepare_for_minor ();
2539
2540         degraded_mode = 0;
2541         objects_pinned = 0;
2542         nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2543         /* FIXME: optimize later to use the higher address where an object can be present */
2544         nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2545
2546         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 ()));
2547         max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2548         g_assert (nursery_section->size >= max_garbage_amount);
2549
2550         /* world must be stopped already */
2551         TV_GETTIME (all_atv);
2552         atv = all_atv;
2553
2554         TV_GETTIME (btv);
2555         time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2556
2557         if (xdomain_checks) {
2558                 sgen_clear_nursery_fragments ();
2559                 check_for_xdomain_refs ();
2560         }
2561
2562         nursery_section->next_data = nursery_next;
2563
2564         major_collector.start_nursery_collection ();
2565
2566         sgen_memgov_minor_collection_start ();
2567
2568         init_gray_queue ();
2569
2570         stat_minor_gcs++;
2571         gc_stats.minor_gc_count ++;
2572
2573         MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2574
2575         sgen_process_fin_stage_entries ();
2576         sgen_process_dislink_stage_entries ();
2577
2578         MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2579
2580         /* pin from pinned handles */
2581         sgen_init_pinning ();
2582         mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2583         pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2584         /* pin cemented objects */
2585         sgen_cement_iterate (pin_stage_object_callback, NULL);
2586         /* identify pinned objects */
2587         sgen_optimize_pin_queue (0);
2588         sgen_pinning_setup_section (nursery_section);
2589         ctx.scan_func = NULL;
2590         ctx.copy_func = NULL;
2591         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2592         sgen_pin_objects_in_section (nursery_section, ctx);
2593         sgen_pinning_trim_queue_to_section (nursery_section);
2594
2595         TV_GETTIME (atv);
2596         time_minor_pinning += TV_ELAPSED (btv, atv);
2597         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2598         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2599
2600         MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2601
2602         if (whole_heap_check_before_collection) {
2603                 sgen_clear_nursery_fragments ();
2604                 sgen_check_whole_heap (finish_up_concurrent_mark);
2605         }
2606         if (consistency_check_at_minor_collection)
2607                 sgen_check_consistency ();
2608
2609         sgen_workers_start_all_workers ();
2610         sgen_workers_start_marking ();
2611
2612         frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2613         frssjd->heap_start = sgen_get_nursery_start ();
2614         frssjd->heap_end = nursery_next;
2615         sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2616
2617         /* we don't have complete write barrier yet, so we scan all the old generation sections */
2618         TV_GETTIME (btv);
2619         time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2620         SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2621
2622         MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2623
2624         if (!sgen_collection_is_parallel ()) {
2625                 ctx.scan_func = current_object_ops.scan_object;
2626                 ctx.copy_func = NULL;
2627                 ctx.queue = &gray_queue;
2628                 sgen_drain_gray_stack (-1, ctx);
2629         }
2630
2631         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2632                 report_registered_roots ();
2633         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2634                 report_finalizer_roots ();
2635         TV_GETTIME (atv);
2636         time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2637
2638         MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2639
2640         /* registered roots, this includes static fields */
2641         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2642         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2643         scrrjd_normal->scan_func = current_object_ops.scan_object;
2644         scrrjd_normal->heap_start = sgen_get_nursery_start ();
2645         scrrjd_normal->heap_end = nursery_next;
2646         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2647         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2648
2649         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2650         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2651         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2652         scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2653         scrrjd_wbarrier->heap_end = nursery_next;
2654         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2655         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2656
2657         TV_GETTIME (btv);
2658         time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2659
2660         MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2661
2662         /* thread data */
2663         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2664         stdjd->heap_start = sgen_get_nursery_start ();
2665         stdjd->heap_end = nursery_next;
2666         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2667
2668         TV_GETTIME (atv);
2669         time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2670         btv = atv;
2671
2672         MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2673
2674         g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2675
2676         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2677                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2678
2679         /* Scan the list of objects ready for finalization. If */
2680         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2681         sfejd_fin_ready->list = fin_ready_list;
2682         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2683
2684         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2685         sfejd_critical_fin->list = critical_fin_list;
2686         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2687
2688         MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2689
2690         finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2691         TV_GETTIME (atv);
2692         time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2693         mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2694
2695         MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2696
2697         /*
2698          * The (single-threaded) finalization code might have done
2699          * some copying/marking so we can only reset the GC thread's
2700          * worker data here instead of earlier when we joined the
2701          * workers.
2702          */
2703         sgen_workers_reset_data ();
2704
2705         if (objects_pinned) {
2706                 sgen_optimize_pin_queue (0);
2707                 sgen_pinning_setup_section (nursery_section);
2708         }
2709
2710         /* walk the pin_queue, build up the fragment list of free memory, unmark
2711          * pinned objects as we go, memzero() the empty fragments so they are ready for the
2712          * next allocations.
2713          */
2714         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2715         fragment_total = sgen_build_nursery_fragments (nursery_section,
2716                         nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2717                         unpin_queue);
2718         if (!fragment_total)
2719                 degraded_mode = 1;
2720
2721         /* Clear TLABs for all threads */
2722         sgen_clear_tlabs ();
2723
2724         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2725         TV_GETTIME (btv);
2726         time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2727         SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2728
2729         if (consistency_check_at_minor_collection)
2730                 sgen_check_major_refs ();
2731
2732         major_collector.finish_nursery_collection ();
2733
2734         TV_GETTIME (all_btv);
2735         gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2736
2737         if (heap_dump_file)
2738                 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2739
2740         /* prepare the pin queue for the next collection */
2741         sgen_finish_pinning ();
2742         if (fin_ready_list || critical_fin_list) {
2743                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2744                 mono_gc_finalize_notify ();
2745         }
2746         sgen_pin_stats_reset ();
2747         /* clear cemented hash */
2748         sgen_cement_clear_below_threshold ();
2749
2750         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2751
2752         remset.finish_minor_collection ();
2753
2754         check_scan_starts ();
2755
2756         binary_protocol_flush_buffers (FALSE);
2757
2758         sgen_memgov_minor_collection_end ();
2759
2760         /*objects are late pinned because of lack of memory, so a major is a good call*/
2761         needs_major = objects_pinned > 0;
2762         current_collection_generation = -1;
2763         objects_pinned = 0;
2764
2765         MONO_GC_END (GENERATION_NURSERY);
2766         binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2767
2768         if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2769                 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2770
2771         return needs_major;
2772 }
2773
2774 static void
2775 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2776 {
2777         ctx->scan_func (obj, ctx->queue);
2778 }
2779
2780 static void
2781 scan_nursery_objects (ScanCopyContext ctx)
2782 {
2783         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2784                         (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2785 }
2786
2787 static void
2788 major_copy_or_mark_from_roots (int *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2789 {
2790         LOSObject *bigobj;
2791         TV_DECLARE (atv);
2792         TV_DECLARE (btv);
2793         /* FIXME: only use these values for the precise scan
2794          * note that to_space pointers should be excluded anyway...
2795          */
2796         char *heap_start = NULL;
2797         char *heap_end = (char*)-1;
2798         gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2799         GCRootReport root_report = { 0 };
2800         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2801         ScanThreadDataJobData *stdjd;
2802         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2803         ScanCopyContext ctx;
2804
2805         if (concurrent_collection_in_progress) {
2806                 /*This cleans up unused fragments */
2807                 sgen_nursery_allocator_prepare_for_pinning ();
2808
2809                 if (do_concurrent_checks)
2810                         check_nursery_is_clean ();
2811         } else {
2812                 /* The concurrent collector doesn't touch the nursery. */
2813                 sgen_nursery_alloc_prepare_for_major ();
2814         }
2815
2816         init_gray_queue ();
2817
2818         TV_GETTIME (atv);
2819
2820         /* Pinning depends on this */
2821         sgen_clear_nursery_fragments ();
2822
2823         if (whole_heap_check_before_collection)
2824                 sgen_check_whole_heap (finish_up_concurrent_mark);
2825
2826         TV_GETTIME (btv);
2827         time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2828
2829         if (!sgen_collection_is_concurrent ())
2830                 nursery_section->next_data = sgen_get_nursery_end ();
2831         /* we should also coalesce scanning from sections close to each other
2832          * and deal with pointers outside of the sections later.
2833          */
2834
2835         objects_pinned = 0;
2836         *major_collector.have_swept = FALSE;
2837
2838         if (xdomain_checks) {
2839                 sgen_clear_nursery_fragments ();
2840                 check_for_xdomain_refs ();
2841         }
2842
2843         if (!concurrent_collection_in_progress) {
2844                 /* Remsets are not useful for a major collection */
2845                 remset.prepare_for_major_collection ();
2846         }
2847
2848         sgen_process_fin_stage_entries ();
2849         sgen_process_dislink_stage_entries ();
2850
2851         TV_GETTIME (atv);
2852         sgen_init_pinning ();
2853         SGEN_LOG (6, "Collecting pinned addresses");
2854         pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2855
2856         if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2857                 if (major_collector.is_concurrent) {
2858                         /*
2859                          * The concurrent major collector cannot evict
2860                          * yet, so we need to pin cemented objects to
2861                          * not break some asserts.
2862                          *
2863                          * FIXME: We could evict now!
2864                          */
2865                         sgen_cement_iterate (pin_stage_object_callback, NULL);
2866                 }
2867
2868                 if (!concurrent_collection_in_progress)
2869                         sgen_cement_reset ();
2870         }
2871
2872         sgen_optimize_pin_queue (0);
2873
2874         /*
2875          * The concurrent collector doesn't move objects, neither on
2876          * the major heap nor in the nursery, so we can mark even
2877          * before pinning has finished.  For the non-concurrent
2878          * collector we start the workers after pinning.
2879          */
2880         if (concurrent_collection_in_progress) {
2881                 sgen_workers_start_all_workers ();
2882                 sgen_workers_start_marking ();
2883         }
2884
2885         /*
2886          * pin_queue now contains all candidate pointers, sorted and
2887          * uniqued.  We must do two passes now to figure out which
2888          * objects are pinned.
2889          *
2890          * The first is to find within the pin_queue the area for each
2891          * section.  This requires that the pin_queue be sorted.  We
2892          * also process the LOS objects and pinned chunks here.
2893          *
2894          * The second, destructive, pass is to reduce the section
2895          * areas to pointers to the actually pinned objects.
2896          */
2897         SGEN_LOG (6, "Pinning from sections");
2898         /* first pass for the sections */
2899         sgen_find_section_pin_queue_start_end (nursery_section);
2900         major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2901         /* identify possible pointers to the insize of large objects */
2902         SGEN_LOG (6, "Pinning from large objects");
2903         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2904                 int dummy;
2905                 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2906                         binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2907
2908 #ifdef ENABLE_DTRACE
2909                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2910                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2911                                 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2912                         }
2913 #endif
2914
2915                         if (sgen_los_object_is_pinned (bigobj->data)) {
2916                                 g_assert (finish_up_concurrent_mark);
2917                                 continue;
2918                         }
2919                         sgen_los_pin_object (bigobj->data);
2920                         /* FIXME: only enqueue if object has references */
2921                         GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2922                         if (G_UNLIKELY (do_pin_stats))
2923                                 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2924                         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));
2925
2926                         if (profile_roots)
2927                                 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2928                 }
2929         }
2930         if (profile_roots)
2931                 notify_gc_roots (&root_report);
2932         /* second pass for the sections */
2933         ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2934         ctx.copy_func = NULL;
2935         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2936
2937         /*
2938          * Concurrent mark never follows references into the nursery.
2939          * In the start and finish pauses we must scan live nursery
2940          * objects, though.  We could simply scan all nursery objects,
2941          * but that would be conservative.  The easiest way is to do a
2942          * nursery collection, which copies all live nursery objects
2943          * (except pinned ones, with the simple nursery) to the major
2944          * heap.  Scanning the mod union table later will then scan
2945          * those promoted objects, provided they're reachable.  Pinned
2946          * objects in the nursery - which we can trivially find in the
2947          * pinning queue - are treated as roots in the mark pauses.
2948          *
2949          * The split nursery complicates the latter part because
2950          * non-pinned objects can survive in the nursery.  That's why
2951          * we need to do a full front-to-back scan of the nursery,
2952          * marking all objects.
2953          *
2954          * Non-concurrent mark evacuates from the nursery, so it's
2955          * sufficient to just scan pinned nursery objects.
2956          */
2957         if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2958                 scan_nursery_objects (ctx);
2959         } else {
2960                 sgen_pin_objects_in_section (nursery_section, ctx);
2961                 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2962                         sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2963         }
2964
2965         major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2966         if (old_next_pin_slot)
2967                 *old_next_pin_slot = sgen_get_pinned_count ();
2968
2969         TV_GETTIME (btv);
2970         time_major_pinning += TV_ELAPSED (atv, btv);
2971         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2972         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2973
2974         major_collector.init_to_space ();
2975
2976 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2977         main_gc_thread = mono_native_thread_self ();
2978 #endif
2979
2980         if (!concurrent_collection_in_progress && major_collector.is_parallel) {
2981                 sgen_workers_start_all_workers ();
2982                 sgen_workers_start_marking ();
2983         }
2984
2985         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2986                 report_registered_roots ();
2987         TV_GETTIME (atv);
2988         time_major_scan_pinned += TV_ELAPSED (btv, atv);
2989
2990         /* registered roots, this includes static fields */
2991         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2992         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2993         scrrjd_normal->scan_func = current_object_ops.scan_object;
2994         scrrjd_normal->heap_start = heap_start;
2995         scrrjd_normal->heap_end = heap_end;
2996         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2997         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2998
2999         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3000         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
3001         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
3002         scrrjd_wbarrier->heap_start = heap_start;
3003         scrrjd_wbarrier->heap_end = heap_end;
3004         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
3005         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
3006
3007         TV_GETTIME (btv);
3008         time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
3009
3010         /* Threads */
3011         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3012         stdjd->heap_start = heap_start;
3013         stdjd->heap_end = heap_end;
3014         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
3015
3016         TV_GETTIME (atv);
3017         time_major_scan_thread_data += TV_ELAPSED (btv, atv);
3018
3019         TV_GETTIME (btv);
3020         time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
3021
3022         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
3023                 report_finalizer_roots ();
3024
3025         /* scan the list of objects ready for finalization */
3026         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3027         sfejd_fin_ready->list = fin_ready_list;
3028         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
3029
3030         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3031         sfejd_critical_fin->list = critical_fin_list;
3032         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
3033
3034         if (scan_mod_union) {
3035                 g_assert (finish_up_concurrent_mark);
3036
3037                 /* Mod union card table */
3038                 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
3039                 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
3040         }
3041
3042         TV_GETTIME (atv);
3043         time_major_scan_finalized += TV_ELAPSED (btv, atv);
3044         SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
3045
3046         TV_GETTIME (btv);
3047         time_major_scan_big_objects += TV_ELAPSED (atv, btv);
3048
3049         if (concurrent_collection_in_progress) {
3050                 /* prepare the pin queue for the next collection */
3051                 sgen_finish_pinning ();
3052
3053                 sgen_pin_stats_reset ();
3054
3055                 if (do_concurrent_checks)
3056                         check_nursery_is_clean ();
3057         }
3058 }
3059
3060 static void
3061 major_start_collection (gboolean concurrent, int *old_next_pin_slot)
3062 {
3063         MONO_GC_BEGIN (GENERATION_OLD);
3064         binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
3065
3066         current_collection_generation = GENERATION_OLD;
3067 #ifndef DISABLE_PERFCOUNTERS
3068         mono_perfcounters->gc_collections1++;
3069 #endif
3070
3071         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3072
3073         if (concurrent) {
3074                 g_assert (major_collector.is_concurrent);
3075                 concurrent_collection_in_progress = TRUE;
3076
3077                 sgen_cement_concurrent_start ();
3078
3079                 current_object_ops = major_collector.major_concurrent_ops;
3080         } else {
3081                 current_object_ops = major_collector.major_ops;
3082         }
3083
3084         reset_pinned_from_failed_allocation ();
3085
3086         sgen_memgov_major_collection_start ();
3087
3088         //count_ref_nonref_objs ();
3089         //consistency_check ();
3090
3091         check_scan_starts ();
3092
3093         degraded_mode = 0;
3094         SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
3095         stat_major_gcs++;
3096         gc_stats.major_gc_count ++;
3097
3098         if (major_collector.start_major_collection)
3099                 major_collector.start_major_collection ();
3100
3101         major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
3102 }
3103
3104 static void
3105 wait_for_workers_to_finish (void)
3106 {
3107         if (concurrent_collection_in_progress || major_collector.is_parallel) {
3108                 gray_queue_redirect (&gray_queue);
3109                 sgen_workers_join ();
3110         }
3111
3112         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3113
3114 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3115         main_gc_thread = NULL;
3116 #endif
3117 }
3118
3119 static void
3120 major_finish_collection (const char *reason, int old_next_pin_slot, gboolean scan_mod_union)
3121 {
3122         LOSObject *bigobj, *prevbo;
3123         TV_DECLARE (atv);
3124         TV_DECLARE (btv);
3125
3126         TV_GETTIME (btv);
3127
3128         if (concurrent_collection_in_progress || major_collector.is_parallel)
3129                 wait_for_workers_to_finish ();
3130
3131         if (concurrent_collection_in_progress) {
3132                 current_object_ops = major_collector.major_concurrent_ops;
3133
3134                 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
3135                 wait_for_workers_to_finish ();
3136
3137                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3138
3139                 if (do_concurrent_checks)
3140                         check_nursery_is_clean ();
3141         } else {
3142                 current_object_ops = major_collector.major_ops;
3143         }
3144
3145         /*
3146          * The workers have stopped so we need to finish gray queue
3147          * work that might result from finalization in the main GC
3148          * thread.  Redirection must therefore be turned off.
3149          */
3150         sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
3151         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3152
3153         /* all the objects in the heap */
3154         finish_gray_stack (GENERATION_OLD, &gray_queue);
3155         TV_GETTIME (atv);
3156         time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3157
3158         /*
3159          * The (single-threaded) finalization code might have done
3160          * some copying/marking so we can only reset the GC thread's
3161          * worker data here instead of earlier when we joined the
3162          * workers.
3163          */
3164         sgen_workers_reset_data ();
3165
3166         if (objects_pinned) {
3167                 g_assert (!concurrent_collection_in_progress);
3168
3169                 /*This is slow, but we just OOM'd*/
3170                 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3171                 sgen_optimize_pin_queue (0);
3172                 sgen_find_section_pin_queue_start_end (nursery_section);
3173                 objects_pinned = 0;
3174         }
3175
3176         reset_heap_boundaries ();
3177         sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3178
3179         if (check_mark_bits_after_major_collection)
3180                 sgen_check_major_heap_marked ();
3181
3182         MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
3183
3184         /* sweep the big objects list */
3185         prevbo = NULL;
3186         for (bigobj = los_object_list; bigobj;) {
3187                 g_assert (!object_is_pinned (bigobj->data));
3188                 if (sgen_los_object_is_pinned (bigobj->data)) {
3189                         sgen_los_unpin_object (bigobj->data);
3190                         sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
3191                 } else {
3192                         LOSObject *to_free;
3193                         /* not referenced anywhere, so we can free it */
3194                         if (prevbo)
3195                                 prevbo->next = bigobj->next;
3196                         else
3197                                 los_object_list = bigobj->next;
3198                         to_free = bigobj;
3199                         bigobj = bigobj->next;
3200                         sgen_los_free_object (to_free);
3201                         continue;
3202                 }
3203                 prevbo = bigobj;
3204                 bigobj = bigobj->next;
3205         }
3206
3207         TV_GETTIME (btv);
3208         time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3209
3210         sgen_los_sweep ();
3211
3212         TV_GETTIME (atv);
3213         time_major_los_sweep += TV_ELAPSED (btv, atv);
3214
3215         major_collector.sweep ();
3216
3217         MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
3218
3219         TV_GETTIME (btv);
3220         time_major_sweep += TV_ELAPSED (atv, btv);
3221
3222         if (!concurrent_collection_in_progress) {
3223                 /* walk the pin_queue, build up the fragment list of free memory, unmark
3224                  * pinned objects as we go, memzero() the empty fragments so they are ready for the
3225                  * next allocations.
3226                  */
3227                 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
3228                         degraded_mode = 1;
3229
3230                 /* prepare the pin queue for the next collection */
3231                 sgen_finish_pinning ();
3232
3233                 /* Clear TLABs for all threads */
3234                 sgen_clear_tlabs ();
3235
3236                 sgen_pin_stats_reset ();
3237         }
3238
3239         if (concurrent_collection_in_progress)
3240                 sgen_cement_concurrent_finish ();
3241         sgen_cement_clear_below_threshold ();
3242
3243         TV_GETTIME (atv);
3244         time_major_fragment_creation += TV_ELAPSED (btv, atv);
3245
3246         if (heap_dump_file)
3247                 dump_heap ("major", stat_major_gcs - 1, reason);
3248
3249         if (fin_ready_list || critical_fin_list) {
3250                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
3251                 mono_gc_finalize_notify ();
3252         }
3253
3254         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3255
3256         sgen_memgov_major_collection_end ();
3257         current_collection_generation = -1;
3258
3259         major_collector.finish_major_collection ();
3260
3261         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3262
3263         if (concurrent_collection_in_progress)
3264                 concurrent_collection_in_progress = FALSE;
3265
3266         check_scan_starts ();
3267
3268         binary_protocol_flush_buffers (FALSE);
3269
3270         //consistency_check ();
3271
3272         MONO_GC_END (GENERATION_OLD);
3273         binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
3274 }
3275
3276 static gboolean
3277 major_do_collection (const char *reason)
3278 {
3279         TV_DECLARE (all_atv);
3280         TV_DECLARE (all_btv);
3281         int old_next_pin_slot;
3282
3283         if (disable_major_collections)
3284                 return FALSE;
3285
3286         if (major_collector.get_and_reset_num_major_objects_marked) {
3287                 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3288                 g_assert (!num_marked);
3289         }
3290
3291         /* world must be stopped already */
3292         TV_GETTIME (all_atv);
3293
3294         major_start_collection (FALSE, &old_next_pin_slot);
3295         major_finish_collection (reason, old_next_pin_slot, FALSE);
3296
3297         TV_GETTIME (all_btv);
3298         gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3299
3300         /* FIXME: also report this to the user, preferably in gc-end. */
3301         if (major_collector.get_and_reset_num_major_objects_marked)
3302                 major_collector.get_and_reset_num_major_objects_marked ();
3303
3304         return bytes_pinned_from_failed_allocation > 0;
3305 }
3306
3307 static void
3308 major_start_concurrent_collection (const char *reason)
3309 {
3310         long long num_objects_marked;
3311
3312         if (disable_major_collections)
3313                 return;
3314
3315         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3316         g_assert (num_objects_marked == 0);
3317
3318         MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3319
3320         // FIXME: store reason and pass it when finishing
3321         major_start_collection (TRUE, NULL);
3322
3323         gray_queue_redirect (&gray_queue);
3324         sgen_workers_wait_for_jobs ();
3325
3326         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3327         MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3328
3329         current_collection_generation = -1;
3330 }
3331
3332 static gboolean
3333 major_update_or_finish_concurrent_collection (gboolean force_finish)
3334 {
3335         SgenGrayQueue unpin_queue;
3336         memset (&unpin_queue, 0, sizeof (unpin_queue));
3337
3338         MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3339
3340         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3341
3342         major_collector.update_cardtable_mod_union ();
3343         sgen_los_update_cardtable_mod_union ();
3344
3345         if (!force_finish && !sgen_workers_all_done ()) {
3346                 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3347                 return FALSE;
3348         }
3349
3350         if (mod_union_consistency_check)
3351                 sgen_check_mod_union_consistency ();
3352
3353         collect_nursery (&unpin_queue, TRUE);
3354
3355         current_collection_generation = GENERATION_OLD;
3356         major_finish_collection ("finishing", -1, TRUE);
3357
3358         if (whole_heap_check_before_collection)
3359                 sgen_check_whole_heap (FALSE);
3360
3361         unpin_objects_from_queue (&unpin_queue);
3362         sgen_gray_object_queue_deinit (&unpin_queue);
3363
3364         MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3365
3366         current_collection_generation = -1;
3367
3368         return TRUE;
3369 }
3370
3371 /*
3372  * Ensure an allocation request for @size will succeed by freeing enough memory.
3373  *
3374  * LOCKING: The GC lock MUST be held.
3375  */
3376 void
3377 sgen_ensure_free_space (size_t size)
3378 {
3379         int generation_to_collect = -1;
3380         const char *reason = NULL;
3381
3382
3383         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3384                 if (sgen_need_major_collection (size)) {
3385                         reason = "LOS overflow";
3386                         generation_to_collect = GENERATION_OLD;
3387                 }
3388         } else {
3389                 if (degraded_mode) {
3390                         if (sgen_need_major_collection (size)) {
3391                                 reason = "Degraded mode overflow";
3392                                 generation_to_collect = GENERATION_OLD;
3393                         }
3394                 } else if (sgen_need_major_collection (size)) {
3395                         reason = "Minor allowance";
3396                         generation_to_collect = GENERATION_OLD;
3397                 } else {
3398                         generation_to_collect = GENERATION_NURSERY;
3399                         reason = "Nursery full";
3400                 }
3401         }
3402
3403         if (generation_to_collect == -1) {
3404                 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3405                         generation_to_collect = GENERATION_OLD;
3406                         reason = "Finish concurrent collection";
3407                 }
3408         }
3409
3410         if (generation_to_collect == -1)
3411                 return;
3412         sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3413 }
3414
3415 /*
3416  * LOCKING: Assumes the GC lock is held.
3417  */
3418 void
3419 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3420 {
3421         TV_DECLARE (gc_end);
3422         GGTimingInfo infos [2];
3423         int overflow_generation_to_collect = -1;
3424         int oldest_generation_collected = generation_to_collect;
3425         const char *overflow_reason = NULL;
3426
3427         MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3428         if (wait_to_finish)
3429                 binary_protocol_collection_force (generation_to_collect);
3430
3431         g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3432
3433         memset (infos, 0, sizeof (infos));
3434         mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3435
3436         infos [0].generation = generation_to_collect;
3437         infos [0].reason = reason;
3438         infos [0].is_overflow = FALSE;
3439         TV_GETTIME (infos [0].total_time);
3440         infos [1].generation = -1;
3441
3442         sgen_stop_world (generation_to_collect);
3443
3444         if (concurrent_collection_in_progress) {
3445                 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3446                         oldest_generation_collected = GENERATION_OLD;
3447                         goto done;
3448                 }
3449                 if (generation_to_collect == GENERATION_OLD)
3450                         goto done;
3451         } else {
3452                 if (generation_to_collect == GENERATION_OLD &&
3453                                 allow_synchronous_major &&
3454                                 major_collector.want_synchronous_collection &&
3455                                 *major_collector.want_synchronous_collection) {
3456                         wait_to_finish = TRUE;
3457                 }
3458         }
3459
3460         //FIXME extract overflow reason
3461         if (generation_to_collect == GENERATION_NURSERY) {
3462                 if (collect_nursery (NULL, FALSE)) {
3463                         overflow_generation_to_collect = GENERATION_OLD;
3464                         overflow_reason = "Minor overflow";
3465                 }
3466         } else {
3467                 if (major_collector.is_concurrent) {
3468                         g_assert (!concurrent_collection_in_progress);
3469                         if (!wait_to_finish)
3470                                 collect_nursery (NULL, FALSE);
3471                 }
3472
3473                 if (major_collector.is_concurrent && !wait_to_finish) {
3474                         major_start_concurrent_collection (reason);
3475                         // FIXME: set infos[0] properly
3476                         goto done;
3477                 } else {
3478                         if (major_do_collection (reason)) {
3479                                 overflow_generation_to_collect = GENERATION_NURSERY;
3480                                 overflow_reason = "Excessive pinning";
3481                         }
3482                 }
3483         }
3484
3485         TV_GETTIME (gc_end);
3486         infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3487
3488
3489         if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3490                 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3491                 infos [1].generation = overflow_generation_to_collect;
3492                 infos [1].reason = overflow_reason;
3493                 infos [1].is_overflow = TRUE;
3494                 infos [1].total_time = gc_end;
3495
3496                 if (overflow_generation_to_collect == GENERATION_NURSERY)
3497                         collect_nursery (NULL, FALSE);
3498                 else
3499                         major_do_collection (overflow_reason);
3500
3501                 TV_GETTIME (gc_end);
3502                 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3503
3504                 /* keep events symmetric */
3505                 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3506
3507                 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3508         }
3509
3510         SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3511
3512         /* this also sets the proper pointers for the next allocation */
3513         if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3514                 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3515                 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3516                 sgen_dump_pin_queue ();
3517                 degraded_mode = 1;
3518         }
3519
3520  done:
3521         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3522
3523         sgen_restart_world (oldest_generation_collected, infos);
3524
3525         mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3526 }
3527
3528 /*
3529  * ######################################################################
3530  * ########  Memory allocation from the OS
3531  * ######################################################################
3532  * This section of code deals with getting memory from the OS and
3533  * allocating memory for GC-internal data structures.
3534  * Internal memory can be handled with a freelist for small objects.
3535  */
3536
3537 /*
3538  * Debug reporting.
3539  */
3540 G_GNUC_UNUSED static void
3541 report_internal_mem_usage (void)
3542 {
3543         printf ("Internal memory usage:\n");
3544         sgen_report_internal_mem_usage ();
3545         printf ("Pinned memory usage:\n");
3546         major_collector.report_pinned_memory_usage ();
3547 }
3548
3549 /*
3550  * ######################################################################
3551  * ########  Finalization support
3552  * ######################################################################
3553  */
3554
3555 static inline gboolean
3556 sgen_major_is_object_alive (void *object)
3557 {
3558         mword objsize;
3559
3560         /* Oldgen objects can be pinned and forwarded too */
3561         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3562                 return TRUE;
3563
3564         /*
3565          * FIXME: major_collector.is_object_live() also calculates the
3566          * size.  Avoid the double calculation.
3567          */
3568         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3569         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3570                 return sgen_los_object_is_pinned (object);
3571
3572         return major_collector.is_object_live (object);
3573 }
3574
3575 /*
3576  * If the object has been forwarded it means it's still referenced from a root.
3577  * If it is pinned it's still alive as well.
3578  * A LOS object is only alive if we have pinned it.
3579  * Return TRUE if @obj is ready to be finalized.
3580  */
3581 static inline gboolean
3582 sgen_is_object_alive (void *object)
3583 {
3584         if (ptr_in_nursery (object))
3585                 return sgen_nursery_is_object_alive (object);
3586
3587         return sgen_major_is_object_alive (object);
3588 }
3589
3590 /*
3591  * This function returns true if @object is either alive or it belongs to the old gen
3592  * and we're currently doing a minor collection.
3593  */
3594 static inline int
3595 sgen_is_object_alive_for_current_gen (char *object)
3596 {
3597         if (ptr_in_nursery (object))
3598                 return sgen_nursery_is_object_alive (object);
3599
3600         if (current_collection_generation == GENERATION_NURSERY)
3601                 return TRUE;
3602
3603         return sgen_major_is_object_alive (object);
3604 }
3605
3606 /*
3607  * This function returns true if @object is either alive and belongs to the
3608  * current collection - major collections are full heap, so old gen objects
3609  * are never alive during a minor collection.
3610  */
3611 static inline int
3612 sgen_is_object_alive_and_on_current_collection (char *object)
3613 {
3614         if (ptr_in_nursery (object))
3615                 return sgen_nursery_is_object_alive (object);
3616
3617         if (current_collection_generation == GENERATION_NURSERY)
3618                 return FALSE;
3619
3620         return sgen_major_is_object_alive (object);
3621 }
3622
3623
3624 gboolean
3625 sgen_gc_is_object_ready_for_finalization (void *object)
3626 {
3627         return !sgen_is_object_alive (object);
3628 }
3629
3630 static gboolean
3631 has_critical_finalizer (MonoObject *obj)
3632 {
3633         MonoClass *class;
3634
3635         if (!mono_defaults.critical_finalizer_object)
3636                 return FALSE;
3637
3638         class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3639
3640         return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3641 }
3642
3643 void
3644 sgen_queue_finalization_entry (MonoObject *obj)
3645 {
3646         FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3647         gboolean critical = has_critical_finalizer (obj);
3648         entry->object = obj;
3649         if (critical) {
3650                 entry->next = critical_fin_list;
3651                 critical_fin_list = entry;
3652         } else {
3653                 entry->next = fin_ready_list;
3654                 fin_ready_list = entry;
3655         }
3656
3657 #ifdef ENABLE_DTRACE
3658         if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3659                 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3660                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3661                 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3662                                 vt->klass->name_space, vt->klass->name, gen, critical);
3663         }
3664 #endif
3665 }
3666
3667 gboolean
3668 sgen_object_is_live (void *obj)
3669 {
3670         return sgen_is_object_alive_and_on_current_collection (obj);
3671 }
3672
3673 /* LOCKING: requires that the GC lock is held */
3674 static void
3675 null_ephemerons_for_domain (MonoDomain *domain)
3676 {
3677         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3678
3679         while (current) {
3680                 MonoObject *object = (MonoObject*)current->array;
3681
3682                 if (object && !object->vtable) {
3683                         EphemeronLinkNode *tmp = current;
3684
3685                         if (prev)
3686                                 prev->next = current->next;
3687                         else
3688                                 ephemeron_list = current->next;
3689
3690                         current = current->next;
3691                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3692                 } else {
3693                         prev = current;
3694                         current = current->next;
3695                 }
3696         }
3697 }
3698
3699 /* LOCKING: requires that the GC lock is held */
3700 static void
3701 clear_unreachable_ephemerons (ScanCopyContext ctx)
3702 {
3703         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3704         GrayQueue *queue = ctx.queue;
3705         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3706         MonoArray *array;
3707         Ephemeron *cur, *array_end;
3708         char *tombstone;
3709
3710         while (current) {
3711                 char *object = current->array;
3712
3713                 if (!sgen_is_object_alive_for_current_gen (object)) {
3714                         EphemeronLinkNode *tmp = current;
3715
3716                         SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3717
3718                         if (prev)
3719                                 prev->next = current->next;
3720                         else
3721                                 ephemeron_list = current->next;
3722
3723                         current = current->next;
3724                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3725
3726                         continue;
3727                 }
3728
3729                 copy_func ((void**)&object, queue);
3730                 current->array = object;
3731
3732                 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3733
3734                 array = (MonoArray*)object;
3735                 cur = mono_array_addr (array, Ephemeron, 0);
3736                 array_end = cur + mono_array_length_fast (array);
3737                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3738
3739                 for (; cur < array_end; ++cur) {
3740                         char *key = (char*)cur->key;
3741
3742                         if (!key || key == tombstone)
3743                                 continue;
3744
3745                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3746                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3747                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3748
3749                         if (!sgen_is_object_alive_for_current_gen (key)) {
3750                                 cur->key = tombstone;
3751                                 cur->value = NULL;
3752                                 continue;
3753                         }
3754                 }
3755                 prev = current;
3756                 current = current->next;
3757         }
3758 }
3759
3760 /*
3761 LOCKING: requires that the GC lock is held
3762
3763 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3764 */
3765 static int
3766 mark_ephemerons_in_range (ScanCopyContext ctx)
3767 {
3768         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3769         GrayQueue *queue = ctx.queue;
3770         int nothing_marked = 1;
3771         EphemeronLinkNode *current = ephemeron_list;
3772         MonoArray *array;
3773         Ephemeron *cur, *array_end;
3774         char *tombstone;
3775
3776         for (current = ephemeron_list; current; current = current->next) {
3777                 char *object = current->array;
3778                 SGEN_LOG (5, "Ephemeron array at %p", object);
3779
3780                 /*It has to be alive*/
3781                 if (!sgen_is_object_alive_for_current_gen (object)) {
3782                         SGEN_LOG (5, "\tnot reachable");
3783                         continue;
3784                 }
3785
3786                 copy_func ((void**)&object, queue);
3787
3788                 array = (MonoArray*)object;
3789                 cur = mono_array_addr (array, Ephemeron, 0);
3790                 array_end = cur + mono_array_length_fast (array);
3791                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3792
3793                 for (; cur < array_end; ++cur) {
3794                         char *key = cur->key;
3795
3796                         if (!key || key == tombstone)
3797                                 continue;
3798
3799                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3800                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3801                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3802
3803                         if (sgen_is_object_alive_for_current_gen (key)) {
3804                                 char *value = cur->value;
3805
3806                                 copy_func ((void**)&cur->key, queue);
3807                                 if (value) {
3808                                         if (!sgen_is_object_alive_for_current_gen (value))
3809                                                 nothing_marked = 0;
3810                                         copy_func ((void**)&cur->value, queue);
3811                                 }
3812                         }
3813                 }
3814         }
3815
3816         SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3817         return nothing_marked;
3818 }
3819
3820 int
3821 mono_gc_invoke_finalizers (void)
3822 {
3823         FinalizeReadyEntry *entry = NULL;
3824         gboolean entry_is_critical = FALSE;
3825         int count = 0;
3826         void *obj;
3827         /* FIXME: batch to reduce lock contention */
3828         while (fin_ready_list || critical_fin_list) {
3829                 LOCK_GC;
3830
3831                 if (entry) {
3832                         FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3833
3834                         /* We have finalized entry in the last
3835                            interation, now we need to remove it from
3836                            the list. */
3837                         if (*list == entry)
3838                                 *list = entry->next;
3839                         else {
3840                                 FinalizeReadyEntry *e = *list;
3841                                 while (e->next != entry)
3842                                         e = e->next;
3843                                 e->next = entry->next;
3844                         }
3845                         sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3846                         entry = NULL;
3847                 }
3848
3849                 /* Now look for the first non-null entry. */
3850                 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3851                         ;
3852                 if (entry) {
3853                         entry_is_critical = FALSE;
3854                 } else {
3855                         entry_is_critical = TRUE;
3856                         for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3857                                 ;
3858                 }
3859
3860                 if (entry) {
3861                         g_assert (entry->object);
3862                         num_ready_finalizers--;
3863                         obj = entry->object;
3864                         entry->object = NULL;
3865                         SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3866                 }
3867
3868                 UNLOCK_GC;
3869
3870                 if (!entry)
3871                         break;
3872
3873                 g_assert (entry->object == NULL);
3874                 count++;
3875                 /* the object is on the stack so it is pinned */
3876                 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3877                 mono_gc_run_finalize (obj, NULL);
3878         }
3879         g_assert (!entry);
3880         return count;
3881 }
3882
3883 gboolean
3884 mono_gc_pending_finalizers (void)
3885 {
3886         return fin_ready_list || critical_fin_list;
3887 }
3888
3889 /*
3890  * ######################################################################
3891  * ########  registered roots support
3892  * ######################################################################
3893  */
3894
3895 /*
3896  * We do not coalesce roots.
3897  */
3898 static int
3899 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3900 {
3901         RootRecord new_root;
3902         int i;
3903         LOCK_GC;
3904         for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3905                 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3906                 /* we allow changing the size and the descriptor (for thread statics etc) */
3907                 if (root) {
3908                         size_t old_size = root->end_root - start;
3909                         root->end_root = start + size;
3910                         g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3911                                           ((root->root_desc == 0) && (descr == NULL)));
3912                         root->root_desc = (mword)descr;
3913                         roots_size += size;
3914                         roots_size -= old_size;
3915                         UNLOCK_GC;
3916                         return TRUE;
3917                 }
3918         }
3919
3920         new_root.end_root = start + size;
3921         new_root.root_desc = (mword)descr;
3922
3923         sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3924         roots_size += size;
3925
3926         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);
3927
3928         UNLOCK_GC;
3929         return TRUE;
3930 }
3931
3932 int
3933 mono_gc_register_root (char *start, size_t size, void *descr)
3934 {
3935         return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3936 }
3937
3938 int
3939 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3940 {
3941         return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3942 }
3943
3944 void
3945 mono_gc_deregister_root (char* addr)
3946 {
3947         int root_type;
3948         RootRecord root;
3949
3950         LOCK_GC;
3951         for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3952                 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3953                         roots_size -= (root.end_root - addr);
3954         }
3955         UNLOCK_GC;
3956 }
3957
3958 /*
3959  * ######################################################################
3960  * ########  Thread handling (stop/start code)
3961  * ######################################################################
3962  */
3963
3964 unsigned int sgen_global_stop_count = 0;
3965
3966 int
3967 sgen_get_current_collection_generation (void)
3968 {
3969         return current_collection_generation;
3970 }
3971
3972 void
3973 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3974 {
3975         gc_callbacks = *callbacks;
3976 }
3977
3978 MonoGCCallbacks *
3979 mono_gc_get_gc_callbacks ()
3980 {
3981         return &gc_callbacks;
3982 }
3983
3984 /* Variables holding start/end nursery so it won't have to be passed at every call */
3985 static void *scan_area_arg_start, *scan_area_arg_end;
3986
3987 void
3988 mono_gc_conservatively_scan_area (void *start, void *end)
3989 {
3990         conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3991 }
3992
3993 void*
3994 mono_gc_scan_object (void *obj)
3995 {
3996         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3997         current_object_ops.copy_or_mark_object (&obj, data->queue);
3998         return obj;
3999 }
4000
4001 /*
4002  * Mark from thread stacks and registers.
4003  */
4004 static void
4005 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
4006 {
4007         SgenThreadInfo *info;
4008
4009         scan_area_arg_start = start_nursery;
4010         scan_area_arg_end = end_nursery;
4011
4012         FOREACH_THREAD (info) {
4013                 if (info->skip) {
4014                         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);
4015                         continue;
4016                 }
4017                 if (info->gc_disabled) {
4018                         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);
4019                         continue;
4020                 }
4021                 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
4022                         SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %d)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, mono_thread_info_run_state (info));
4023                         continue;
4024                 }
4025                 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 ());
4026                 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
4027                         UserCopyOrMarkData data = { NULL, queue };
4028                         set_user_copy_or_mark_data (&data);
4029                         gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
4030                         set_user_copy_or_mark_data (NULL);
4031                 } else if (!precise) {
4032                         if (!conservative_stack_mark) {
4033                                 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
4034                                 conservative_stack_mark = TRUE;
4035                         }
4036                         conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
4037                 }
4038
4039                 if (!precise) {
4040 #ifdef USE_MONO_CTX
4041                         conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
4042                                 start_nursery, end_nursery, PIN_TYPE_STACK);
4043 #else
4044                         conservatively_pin_objects_from (&info->regs, &info->regs + ARCH_NUM_REGS,
4045                                         start_nursery, end_nursery, PIN_TYPE_STACK);
4046 #endif
4047                 }
4048         } END_FOREACH_THREAD
4049 }
4050
4051 static gboolean
4052 ptr_on_stack (void *ptr)
4053 {
4054         gpointer stack_start = &stack_start;
4055         SgenThreadInfo *info = mono_thread_info_current ();
4056
4057         if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
4058                 return TRUE;
4059         return FALSE;
4060 }
4061
4062 static void*
4063 sgen_thread_register (SgenThreadInfo* info, void *addr)
4064 {
4065 #ifndef HAVE_KW_THREAD
4066         info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
4067
4068         g_assert (!mono_native_tls_get_value (thread_info_key));
4069         mono_native_tls_set_value (thread_info_key, info);
4070 #else
4071         sgen_thread_info = info;
4072 #endif
4073
4074 #ifdef SGEN_POSIX_STW
4075         info->stop_count = -1;
4076         info->signal = 0;
4077 #endif
4078         info->skip = 0;
4079         info->stack_start = NULL;
4080         info->stopped_ip = NULL;
4081         info->stopped_domain = NULL;
4082 #ifdef USE_MONO_CTX
4083         memset (&info->ctx, 0, sizeof (MonoContext));
4084 #else
4085         memset (&info->regs, 0, sizeof (info->regs));
4086 #endif
4087
4088         sgen_init_tlab_info (info);
4089
4090         binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4091
4092         /* try to get it with attributes first */
4093 #if (defined(HAVE_PTHREAD_GETATTR_NP) || defined(HAVE_PTHREAD_ATTR_GET_NP)) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4094   {
4095      size_t size;
4096      void *sstart;
4097      pthread_attr_t attr;
4098
4099 #if defined(HAVE_PTHREAD_GETATTR_NP)
4100     /* Linux */
4101     pthread_getattr_np (pthread_self (), &attr);
4102 #elif defined(HAVE_PTHREAD_ATTR_GET_NP)
4103     /* BSD */
4104     pthread_attr_init (&attr);
4105     pthread_attr_get_np (pthread_self (), &attr);
4106 #else
4107 #error Cannot determine which API is needed to retrieve pthread attributes.
4108 #endif
4109
4110      pthread_attr_getstack (&attr, &sstart, &size);
4111      info->stack_start_limit = sstart;
4112      info->stack_end = (char*)sstart + size;
4113      pthread_attr_destroy (&attr);
4114   }
4115 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4116                  info->stack_end = (char*)pthread_get_stackaddr_np (pthread_self ());
4117                  info->stack_start_limit = (char*)info->stack_end - pthread_get_stacksize_np (pthread_self ());
4118 #else
4119         {
4120                 /* FIXME: we assume the stack grows down */
4121                 gsize stack_bottom = (gsize)addr;
4122                 stack_bottom += 4095;
4123                 stack_bottom &= ~4095;
4124                 info->stack_end = (char*)stack_bottom;
4125         }
4126 #endif
4127
4128 #ifdef HAVE_KW_THREAD
4129         stack_end = info->stack_end;
4130 #endif
4131
4132         SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
4133
4134         if (gc_callbacks.thread_attach_func)
4135                 info->runtime_data = gc_callbacks.thread_attach_func ();
4136         return info;
4137 }
4138
4139 static void
4140 sgen_thread_unregister (SgenThreadInfo *p)
4141 {
4142         /* If a delegate is passed to native code and invoked on a thread we dont
4143          * know about, the jit will register it with mono_jit_thread_attach, but
4144          * we have no way of knowing when that thread goes away.  SGen has a TSD
4145          * so we assume that if the domain is still registered, we can detach
4146          * the thread
4147          */
4148         if (mono_domain_get ())
4149                 mono_thread_detach (mono_thread_current ());
4150
4151         binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4152         SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)mono_thread_info_get_tid (p));
4153
4154         if (gc_callbacks.thread_detach_func) {
4155                 gc_callbacks.thread_detach_func (p->runtime_data);
4156                 p->runtime_data = NULL;
4157         }
4158 }
4159
4160
4161 static void
4162 sgen_thread_attach (SgenThreadInfo *info)
4163 {
4164         LOCK_GC;
4165         /*this is odd, can we get attached before the gc is inited?*/
4166         init_stats ();
4167         UNLOCK_GC;
4168
4169         if (gc_callbacks.thread_attach_func && !info->runtime_data)
4170                 info->runtime_data = gc_callbacks.thread_attach_func ();
4171 }
4172 gboolean
4173 mono_gc_register_thread (void *baseptr)
4174 {
4175         return mono_thread_info_attach (baseptr) != NULL;
4176 }
4177
4178 /*
4179  * mono_gc_set_stack_end:
4180  *
4181  *   Set the end of the current threads stack to STACK_END. The stack space between
4182  * STACK_END and the real end of the threads stack will not be scanned during collections.
4183  */
4184 void
4185 mono_gc_set_stack_end (void *stack_end)
4186 {
4187         SgenThreadInfo *info;
4188
4189         LOCK_GC;
4190         info = mono_thread_info_current ();
4191         if (info) {
4192                 g_assert (stack_end < info->stack_end);
4193                 info->stack_end = stack_end;
4194         }
4195         UNLOCK_GC;
4196 }
4197
4198 #if USE_PTHREAD_INTERCEPT
4199
4200
4201 int
4202 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4203 {
4204         return pthread_create (new_thread, attr, start_routine, arg);
4205 }
4206
4207 int
4208 mono_gc_pthread_join (pthread_t thread, void **retval)
4209 {
4210         return pthread_join (thread, retval);
4211 }
4212
4213 int
4214 mono_gc_pthread_detach (pthread_t thread)
4215 {
4216         return pthread_detach (thread);
4217 }
4218
4219 void
4220 mono_gc_pthread_exit (void *retval)
4221 {
4222         mono_thread_info_dettach ();
4223         pthread_exit (retval);
4224 }
4225
4226 #endif /* USE_PTHREAD_INTERCEPT */
4227
4228 /*
4229  * ######################################################################
4230  * ########  Write barriers
4231  * ######################################################################
4232  */
4233
4234 /*
4235  * Note: the write barriers first do the needed GC work and then do the actual store:
4236  * this way the value is visible to the conservative GC scan after the write barrier
4237  * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4238  * the conservative scan, otherwise by the remembered set scan.
4239  */
4240 void
4241 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4242 {
4243         HEAVY_STAT (++stat_wbarrier_set_field);
4244         if (ptr_in_nursery (field_ptr)) {
4245                 *(void**)field_ptr = value;
4246                 return;
4247         }
4248         SGEN_LOG (8, "Adding remset at %p", field_ptr);
4249         if (value)
4250                 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4251
4252         remset.wbarrier_set_field (obj, field_ptr, value);
4253 }
4254
4255 void
4256 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4257 {
4258         HEAVY_STAT (++stat_wbarrier_set_arrayref);
4259         if (ptr_in_nursery (slot_ptr)) {
4260                 *(void**)slot_ptr = value;
4261                 return;
4262         }
4263         SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4264         if (value)
4265                 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4266
4267         remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4268 }
4269
4270 void
4271 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4272 {
4273         HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4274         /*This check can be done without taking a lock since dest_ptr array is pinned*/
4275         if (ptr_in_nursery (dest_ptr) || count <= 0) {
4276                 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4277                 return;
4278         }
4279
4280 #ifdef SGEN_BINARY_PROTOCOL
4281         {
4282                 int i;
4283                 for (i = 0; i < count; ++i) {
4284                         gpointer dest = (gpointer*)dest_ptr + i;
4285                         gpointer obj = *((gpointer*)src_ptr + i);
4286                         if (obj)
4287                                 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4288                 }
4289         }
4290 #endif
4291
4292         remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4293 }
4294
4295 static char *found_obj;
4296
4297 static void
4298 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4299 {
4300         char *ptr = user_data;
4301
4302         if (ptr >= obj && ptr < obj + size) {
4303                 g_assert (!found_obj);
4304                 found_obj = obj;
4305         }
4306 }
4307
4308 /* for use in the debugger */
4309 char* find_object_for_ptr (char *ptr);
4310 char*
4311 find_object_for_ptr (char *ptr)
4312 {
4313         if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4314                 found_obj = NULL;
4315                 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4316                                 find_object_for_ptr_callback, ptr, TRUE);
4317                 if (found_obj)
4318                         return found_obj;
4319         }
4320
4321         found_obj = NULL;
4322         sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4323         if (found_obj)
4324                 return found_obj;
4325
4326         /*
4327          * Very inefficient, but this is debugging code, supposed to
4328          * be called from gdb, so we don't care.
4329          */
4330         found_obj = NULL;
4331         major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4332         return found_obj;
4333 }
4334
4335 void
4336 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4337 {
4338         gpointer obj;
4339
4340         HEAVY_STAT (++stat_wbarrier_generic_store);
4341
4342 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4343         /* FIXME: ptr_in_heap must be called with the GC lock held */
4344         if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4345                 char *start = find_object_for_ptr (ptr);
4346                 MonoObject *value = *(MonoObject**)ptr;
4347                 LOCK_GC;
4348                 g_assert (start);
4349                 if (start) {
4350                         MonoObject *obj = (MonoObject*)start;
4351                         if (obj->vtable->domain != value->vtable->domain)
4352                                 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4353                 }
4354                 UNLOCK_GC;
4355         }
4356 #endif
4357
4358         obj = *(gpointer*)ptr;
4359         if (obj)
4360                 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4361
4362         if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4363                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4364                 return;
4365         }
4366
4367         /*
4368          * We need to record old->old pointer locations for the
4369          * concurrent collector.
4370          */
4371         if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4372                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4373                 return;
4374         }
4375
4376         SGEN_LOG (8, "Adding remset at %p", ptr);
4377
4378         remset.wbarrier_generic_nostore (ptr);
4379 }
4380
4381 void
4382 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4383 {
4384         SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4385         *(void**)ptr = value;
4386         if (ptr_in_nursery (value))
4387                 mono_gc_wbarrier_generic_nostore (ptr);
4388         sgen_dummy_use (value);
4389 }
4390
4391 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4392 {
4393         mword *dest = _dest;
4394         mword *src = _src;
4395
4396         while (size) {
4397                 if (bitmap & 0x1)
4398                         mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4399                 else
4400                         *dest = *src;
4401                 ++src;
4402                 ++dest;
4403                 size -= SIZEOF_VOID_P;
4404                 bitmap >>= 1;
4405         }
4406 }
4407
4408 #ifdef SGEN_BINARY_PROTOCOL
4409 #undef HANDLE_PTR
4410 #define HANDLE_PTR(ptr,obj) do {                                        \
4411                 gpointer o = *(gpointer*)(ptr);                         \
4412                 if ((o)) {                                              \
4413                         gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4414                         binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4415                 }                                                       \
4416         } while (0)
4417
4418 static void
4419 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4420 {
4421 #define SCAN_OBJECT_NOVTABLE
4422 #include "sgen-scan-object.h"
4423 }
4424 #endif
4425
4426 void
4427 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4428 {
4429         HEAVY_STAT (++stat_wbarrier_value_copy);
4430         g_assert (klass->valuetype);
4431
4432         SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4433
4434         if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4435                 size_t element_size = mono_class_value_size (klass, NULL);
4436                 size_t size = count * element_size;
4437                 mono_gc_memmove (dest, src, size);
4438                 return;
4439         }
4440
4441 #ifdef SGEN_BINARY_PROTOCOL
4442         {
4443                 size_t element_size = mono_class_value_size (klass, NULL);
4444                 int i;
4445                 for (i = 0; i < count; ++i) {
4446                         scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4447                                         (char*)src + i * element_size - sizeof (MonoObject),
4448                                         (mword) klass->gc_descr);
4449                 }
4450         }
4451 #endif
4452
4453         remset.wbarrier_value_copy (dest, src, count, klass);
4454 }
4455
4456 /**
4457  * mono_gc_wbarrier_object_copy:
4458  *
4459  * Write barrier to call when obj is the result of a clone or copy of an object.
4460  */
4461 void
4462 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4463 {
4464         int size;
4465
4466         HEAVY_STAT (++stat_wbarrier_object_copy);
4467
4468         if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4469                 size = mono_object_class (obj)->instance_size;
4470                 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4471                                 size - sizeof (MonoObject));
4472                 return;
4473         }
4474
4475 #ifdef SGEN_BINARY_PROTOCOL
4476         scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4477 #endif
4478
4479         remset.wbarrier_object_copy (obj, src);
4480 }
4481
4482
4483 /*
4484  * ######################################################################
4485  * ########  Other mono public interface functions.
4486  * ######################################################################
4487  */
4488
4489 #define REFS_SIZE 128
4490 typedef struct {
4491         void *data;
4492         MonoGCReferences callback;
4493         int flags;
4494         int count;
4495         int called;
4496         MonoObject *refs [REFS_SIZE];
4497         uintptr_t offsets [REFS_SIZE];
4498 } HeapWalkInfo;
4499
4500 #undef HANDLE_PTR
4501 #define HANDLE_PTR(ptr,obj)     do {    \
4502                 if (*(ptr)) {   \
4503                         if (hwi->count == REFS_SIZE) {  \
4504                                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);    \
4505                                 hwi->count = 0; \
4506                                 hwi->called = 1;        \
4507                         }       \
4508                         hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start;  \
4509                         hwi->refs [hwi->count++] = *(ptr);      \
4510                 }       \
4511         } while (0)
4512
4513 static void
4514 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4515 {
4516 #include "sgen-scan-object.h"
4517 }
4518
4519 static void
4520 walk_references (char *start, size_t size, void *data)
4521 {
4522         HeapWalkInfo *hwi = data;
4523         hwi->called = 0;
4524         hwi->count = 0;
4525         collect_references (hwi, start, size);
4526         if (hwi->count || !hwi->called)
4527                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4528 }
4529
4530 /**
4531  * mono_gc_walk_heap:
4532  * @flags: flags for future use
4533  * @callback: a function pointer called for each object in the heap
4534  * @data: a user data pointer that is passed to callback
4535  *
4536  * This function can be used to iterate over all the live objects in the heap:
4537  * for each object, @callback is invoked, providing info about the object's
4538  * location in memory, its class, its size and the objects it references.
4539  * For each referenced object it's offset from the object address is
4540  * reported in the offsets array.
4541  * The object references may be buffered, so the callback may be invoked
4542  * multiple times for the same object: in all but the first call, the size
4543  * argument will be zero.
4544  * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4545  * profiler event handler.
4546  *
4547  * Returns: a non-zero value if the GC doesn't support heap walking
4548  */
4549 int
4550 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4551 {
4552         HeapWalkInfo hwi;
4553
4554         hwi.flags = flags;
4555         hwi.callback = callback;
4556         hwi.data = data;
4557
4558         sgen_clear_nursery_fragments ();
4559         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4560
4561         major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4562         sgen_los_iterate_objects (walk_references, &hwi);
4563
4564         return 0;
4565 }
4566
4567 void
4568 mono_gc_collect (int generation)
4569 {
4570         LOCK_GC;
4571         if (generation > 1)
4572                 generation = 1;
4573         sgen_perform_collection (0, generation, "user request", TRUE);
4574         UNLOCK_GC;
4575 }
4576
4577 int
4578 mono_gc_max_generation (void)
4579 {
4580         return 1;
4581 }
4582
4583 int
4584 mono_gc_collection_count (int generation)
4585 {
4586         if (generation == 0)
4587                 return stat_minor_gcs;
4588         return stat_major_gcs;
4589 }
4590
4591 int64_t
4592 mono_gc_get_used_size (void)
4593 {
4594         gint64 tot = 0;
4595         LOCK_GC;
4596         tot = los_memory_usage;
4597         tot += nursery_section->next_data - nursery_section->data;
4598         tot += major_collector.get_used_size ();
4599         /* FIXME: account for pinned objects */
4600         UNLOCK_GC;
4601         return tot;
4602 }
4603
4604 int
4605 mono_gc_get_los_limit (void)
4606 {
4607         return MAX_SMALL_OBJ_SIZE;
4608 }
4609
4610 gboolean
4611 mono_gc_user_markers_supported (void)
4612 {
4613         return TRUE;
4614 }
4615
4616 gboolean
4617 mono_object_is_alive (MonoObject* o)
4618 {
4619         return TRUE;
4620 }
4621
4622 int
4623 mono_gc_get_generation (MonoObject *obj)
4624 {
4625         if (ptr_in_nursery (obj))
4626                 return 0;
4627         return 1;
4628 }
4629
4630 void
4631 mono_gc_enable_events (void)
4632 {
4633 }
4634
4635 void
4636 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4637 {
4638         sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4639 }
4640
4641 void
4642 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4643 {
4644         sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4645 }
4646
4647 MonoObject*
4648 mono_gc_weak_link_get (void **link_addr)
4649 {
4650         void * volatile *link_addr_volatile;
4651         void *ptr;
4652         MonoObject *obj;
4653  retry:
4654         link_addr_volatile = link_addr;
4655         ptr = (void*)*link_addr_volatile;
4656         /*
4657          * At this point we have a hidden pointer.  If the GC runs
4658          * here, it will not recognize the hidden pointer as a
4659          * reference, and if the object behind it is not referenced
4660          * elsewhere, it will be freed.  Once the world is restarted
4661          * we reveal the pointer, giving us a pointer to a freed
4662          * object.  To make sure we don't return it, we load the
4663          * hidden pointer again.  If it's still the same, we can be
4664          * sure the object reference is valid.
4665          */
4666         if (ptr)
4667                 obj = (MonoObject*) REVEAL_POINTER (ptr);
4668         else
4669                 return NULL;
4670
4671         mono_memory_barrier ();
4672
4673         /*
4674          * During the second bridge processing step the world is
4675          * running again.  That step processes all weak links once
4676          * more to null those that refer to dead objects.  Before that
4677          * is completed, those links must not be followed, so we
4678          * conservatively wait for bridge processing when any weak
4679          * link is dereferenced.
4680          */
4681         if (G_UNLIKELY (bridge_processing_in_progress))
4682                 mono_gc_wait_for_bridge_processing ();
4683
4684         if ((void*)*link_addr_volatile != ptr)
4685                 goto retry;
4686
4687         return obj;
4688 }
4689
4690 gboolean
4691 mono_gc_ephemeron_array_add (MonoObject *obj)
4692 {
4693         EphemeronLinkNode *node;
4694
4695         LOCK_GC;
4696
4697         node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4698         if (!node) {
4699                 UNLOCK_GC;
4700                 return FALSE;
4701         }
4702         node->array = (char*)obj;
4703         node->next = ephemeron_list;
4704         ephemeron_list = node;
4705
4706         SGEN_LOG (5, "Registered ephemeron array %p", obj);
4707
4708         UNLOCK_GC;
4709         return TRUE;
4710 }
4711
4712 gboolean
4713 mono_gc_set_allow_synchronous_major (gboolean flag)
4714 {
4715         if (!major_collector.is_concurrent)
4716                 return flag;
4717
4718         allow_synchronous_major = flag;
4719         return TRUE;
4720 }
4721
4722 void*
4723 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4724 {
4725         void *result;
4726         LOCK_INTERRUPTION;
4727         result = func (data);
4728         UNLOCK_INTERRUPTION;
4729         return result;
4730 }
4731
4732 gboolean
4733 mono_gc_is_gc_thread (void)
4734 {
4735         gboolean result;
4736         LOCK_GC;
4737         result = mono_thread_info_current () != NULL;
4738         UNLOCK_GC;
4739         return result;
4740 }
4741
4742 static gboolean
4743 is_critical_method (MonoMethod *method)
4744 {
4745         return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4746 }
4747
4748 void
4749 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4750 {
4751         va_list ap;
4752
4753         va_start (ap, description_format);
4754
4755         fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4756         vfprintf (stderr, description_format, ap);
4757         if (fallback)
4758                 fprintf (stderr, " - %s", fallback);
4759         fprintf (stderr, "\n");
4760
4761         va_end (ap);
4762 }
4763
4764 static gboolean
4765 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4766 {
4767         char *endptr;
4768         double val = strtod (opt, &endptr);
4769         if (endptr == opt) {
4770                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4771                 return FALSE;
4772         }
4773         else if (val < min || val > max) {
4774                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4775                 return FALSE;
4776         }
4777         *result = val;
4778         return TRUE;
4779 }
4780
4781 void
4782 mono_gc_base_init (void)
4783 {
4784         MonoThreadInfoCallbacks cb;
4785         const char *env;
4786         char **opts, **ptr;
4787         char *major_collector_opt = NULL;
4788         char *minor_collector_opt = NULL;
4789         glong max_heap = 0;
4790         glong soft_limit = 0;
4791         int num_workers;
4792         int result;
4793         int dummy;
4794         gboolean debug_print_allowance = FALSE;
4795         double allowance_ratio = 0, save_target = 0;
4796         gboolean have_split_nursery = FALSE;
4797         gboolean cement_enabled = TRUE;
4798
4799         do {
4800                 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4801                 switch (result) {
4802                 case 1:
4803                         /* already inited */
4804                         return;
4805                 case -1:
4806                         /* being inited by another thread */
4807                         g_usleep (1000);
4808                         break;
4809                 case 0:
4810                         /* we will init it */
4811                         break;
4812                 default:
4813                         g_assert_not_reached ();
4814                 }
4815         } while (result != 0);
4816
4817         LOCK_INIT (gc_mutex);
4818
4819         pagesize = mono_pagesize ();
4820         gc_debug_file = stderr;
4821
4822         cb.thread_register = sgen_thread_register;
4823         cb.thread_unregister = sgen_thread_unregister;
4824         cb.thread_attach = sgen_thread_attach;
4825         cb.mono_method_is_critical = (gpointer)is_critical_method;
4826 #ifndef HOST_WIN32
4827         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4828 #endif
4829
4830         mono_threads_init (&cb, sizeof (SgenThreadInfo));
4831
4832         LOCK_INIT (sgen_interruption_mutex);
4833         LOCK_INIT (pin_queue_mutex);
4834
4835         init_user_copy_or_mark_key ();
4836
4837         if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4838                 opts = g_strsplit (env, ",", -1);
4839                 for (ptr = opts; *ptr; ++ptr) {
4840                         char *opt = *ptr;
4841                         if (g_str_has_prefix (opt, "major=")) {
4842                                 opt = strchr (opt, '=') + 1;
4843                                 major_collector_opt = g_strdup (opt);
4844                         } else if (g_str_has_prefix (opt, "minor=")) {
4845                                 opt = strchr (opt, '=') + 1;
4846                                 minor_collector_opt = g_strdup (opt);
4847                         }
4848                 }
4849         } else {
4850                 opts = NULL;
4851         }
4852
4853         init_stats ();
4854         sgen_init_internal_allocator ();
4855         sgen_init_nursery_allocator ();
4856         sgen_init_fin_weak_hash ();
4857
4858         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4859         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4860         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4861         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4862
4863 #ifndef HAVE_KW_THREAD
4864         mono_native_tls_alloc (&thread_info_key, NULL);
4865 #if defined(__APPLE__) || defined (HOST_WIN32)
4866         /*
4867          * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4868          * where the two are the same.
4869          */
4870         mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4871 #endif
4872 #else
4873         {
4874                 int tls_offset = -1;
4875                 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4876                 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4877         }
4878 #endif
4879
4880         /*
4881          * This needs to happen before any internal allocations because
4882          * it inits the small id which is required for hazard pointer
4883          * operations.
4884          */
4885         sgen_os_init ();
4886
4887         mono_thread_info_attach (&dummy);
4888
4889         if (!minor_collector_opt) {
4890                 sgen_simple_nursery_init (&sgen_minor_collector);
4891         } else {
4892                 if (!strcmp (minor_collector_opt, "simple")) {
4893                 use_simple_nursery:
4894                         sgen_simple_nursery_init (&sgen_minor_collector);
4895                 } else if (!strcmp (minor_collector_opt, "split")) {
4896                         sgen_split_nursery_init (&sgen_minor_collector);
4897                         have_split_nursery = TRUE;
4898                 } else {
4899                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4900                         goto use_simple_nursery;
4901                 }
4902         }
4903
4904         if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4905         use_marksweep_major:
4906                 sgen_marksweep_init (&major_collector);
4907         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4908                 sgen_marksweep_fixed_init (&major_collector);
4909         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4910                 sgen_marksweep_par_init (&major_collector);
4911         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4912                 sgen_marksweep_fixed_par_init (&major_collector);
4913         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4914                 sgen_marksweep_conc_init (&major_collector);
4915         } else {
4916                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4917                 goto use_marksweep_major;
4918         }
4919
4920         if (have_split_nursery && major_collector.is_parallel) {
4921                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4922                 have_split_nursery = FALSE;
4923         }
4924
4925         num_workers = mono_cpu_count ();
4926         g_assert (num_workers > 0);
4927         if (num_workers > 16)
4928                 num_workers = 16;
4929
4930         ///* Keep this the default for now */
4931         /* Precise marking is broken on all supported targets. Disable until fixed. */
4932         conservative_stack_mark = TRUE;
4933
4934         sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4935
4936         if (opts) {
4937                 gboolean usage_printed = FALSE;
4938
4939                 for (ptr = opts; *ptr; ++ptr) {
4940                         char *opt = *ptr;
4941                         if (!strcmp (opt, ""))
4942                                 continue;
4943                         if (g_str_has_prefix (opt, "major="))
4944                                 continue;
4945                         if (g_str_has_prefix (opt, "minor="))
4946                                 continue;
4947                         if (g_str_has_prefix (opt, "max-heap-size=")) {
4948                                 glong max_heap_candidate = 0;
4949                                 opt = strchr (opt, '=') + 1;
4950                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4951                                         max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(glong)(mono_pagesize () - 1);
4952                                         if (max_heap != max_heap_candidate)
4953                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4954                                 } else {
4955                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4956                                 }
4957                                 continue;
4958                         }
4959                         if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4960                                 opt = strchr (opt, '=') + 1;
4961                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4962                                         if (soft_limit <= 0) {
4963                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4964                                                 soft_limit = 0;
4965                                         }
4966                                 } else {
4967                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4968                                 }
4969                                 continue;
4970                         }
4971                         if (g_str_has_prefix (opt, "workers=")) {
4972                                 long val;
4973                                 char *endptr;
4974                                 if (!major_collector.is_parallel) {
4975                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
4976                                         continue;
4977                                 }
4978                                 opt = strchr (opt, '=') + 1;
4979                                 val = strtol (opt, &endptr, 10);
4980                                 if (!*opt || *endptr) {
4981                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
4982                                         continue;
4983                                 }
4984                                 if (val <= 0 || val > 16) {
4985                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
4986                                         continue;
4987                                 }
4988                                 num_workers = (int)val;
4989                                 continue;
4990                         }
4991                         if (g_str_has_prefix (opt, "stack-mark=")) {
4992                                 opt = strchr (opt, '=') + 1;
4993                                 if (!strcmp (opt, "precise")) {
4994                                         conservative_stack_mark = FALSE;
4995                                 } else if (!strcmp (opt, "conservative")) {
4996                                         conservative_stack_mark = TRUE;
4997                                 } else {
4998                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4999                                                         "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
5000                                 }
5001                                 continue;
5002                         }
5003                         if (g_str_has_prefix (opt, "bridge=")) {
5004                                 opt = strchr (opt, '=') + 1;
5005                                 sgen_register_test_bridge_callbacks (g_strdup (opt));
5006                                 continue;
5007                         }
5008 #ifdef USER_CONFIG
5009                         if (g_str_has_prefix (opt, "nursery-size=")) {
5010                                 long val;
5011                                 opt = strchr (opt, '=') + 1;
5012                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
5013 #ifdef SGEN_ALIGN_NURSERY
5014                                         if ((val & (val - 1))) {
5015                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
5016                                                 continue;
5017                                         }
5018
5019                                         if (val < SGEN_MAX_NURSERY_WASTE) {
5020                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
5021                                                                 "`nursery-size` must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
5022                                                 continue;
5023                                         }
5024
5025                                         sgen_nursery_size = val;
5026                                         sgen_nursery_bits = 0;
5027                                         while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
5028                                                 ;
5029 #else
5030                                         sgen_nursery_size = val;
5031 #endif
5032                                 } else {
5033                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
5034                                         continue;
5035                                 }
5036                                 continue;
5037                         }
5038 #endif
5039                         if (g_str_has_prefix (opt, "save-target-ratio=")) {
5040                                 double val;
5041                                 opt = strchr (opt, '=') + 1;
5042                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
5043                                                 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
5044                                         save_target = val;
5045                                 }
5046                                 continue;
5047                         }
5048                         if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
5049                                 double val;
5050                                 opt = strchr (opt, '=') + 1;
5051                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
5052                                                 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
5053                                         allowance_ratio = val;
5054                                 }
5055                                 continue;
5056                         }
5057                         if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
5058                                 if (!major_collector.is_concurrent) {
5059                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
5060                                         continue;
5061                                 }
5062
5063                                 opt = strchr (opt, '=') + 1;
5064
5065                                 if (!strcmp (opt, "yes")) {
5066                                         allow_synchronous_major = TRUE;
5067                                 } else if (!strcmp (opt, "no")) {
5068                                         allow_synchronous_major = FALSE;
5069                                 } else {
5070                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
5071                                         continue;
5072                                 }
5073                         }
5074
5075                         if (!strcmp (opt, "cementing")) {
5076                                 if (major_collector.is_parallel) {
5077                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported for the parallel major collector.");
5078                                         continue;
5079                                 }
5080                                 cement_enabled = TRUE;
5081                                 continue;
5082                         }
5083                         if (!strcmp (opt, "no-cementing")) {
5084                                 cement_enabled = FALSE;
5085                                 continue;
5086                         }
5087
5088                         if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
5089                                 continue;
5090
5091                         if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
5092                                 continue;
5093
5094                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5095
5096                         if (usage_printed)
5097                                 continue;
5098
5099                         fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
5100                         fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5101                         fprintf (stderr, "  soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
5102                         fprintf (stderr, "  nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5103                         fprintf (stderr, "  major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
5104                         fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
5105                         fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
5106                         fprintf (stderr, "  stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
5107                         fprintf (stderr, "  [no-]cementing\n");
5108                         if (major_collector.is_concurrent)
5109                                 fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
5110                         if (major_collector.print_gc_param_usage)
5111                                 major_collector.print_gc_param_usage ();
5112                         if (sgen_minor_collector.print_gc_param_usage)
5113                                 sgen_minor_collector.print_gc_param_usage ();
5114                         fprintf (stderr, " Experimental options:\n");
5115                         fprintf (stderr, "  save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
5116                         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);
5117                         fprintf (stderr, "\n");
5118
5119                         usage_printed = TRUE;
5120                 }
5121                 g_strfreev (opts);
5122         }
5123
5124         if (major_collector.is_parallel) {
5125                 cement_enabled = FALSE;
5126                 sgen_workers_init (num_workers);
5127         } else if (major_collector.is_concurrent) {
5128                 sgen_workers_init (1);
5129         }
5130
5131         if (major_collector_opt)
5132                 g_free (major_collector_opt);
5133
5134         if (minor_collector_opt)
5135                 g_free (minor_collector_opt);
5136
5137         alloc_nursery ();
5138
5139         sgen_cement_init (cement_enabled);
5140
5141         if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
5142                 gboolean usage_printed = FALSE;
5143
5144                 opts = g_strsplit (env, ",", -1);
5145                 for (ptr = opts; ptr && *ptr; ptr ++) {
5146                         char *opt = *ptr;
5147                         if (!strcmp (opt, ""))
5148                                 continue;
5149                         if (opt [0] >= '0' && opt [0] <= '9') {
5150                                 gc_debug_level = atoi (opt);
5151                                 opt++;
5152                                 if (opt [0] == ':')
5153                                         opt++;
5154                                 if (opt [0]) {
5155 #ifdef HOST_WIN32
5156                                         char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
5157 #else
5158                                         char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
5159 #endif
5160                                         gc_debug_file = fopen (rf, "wb");
5161                                         if (!gc_debug_file)
5162                                                 gc_debug_file = stderr;
5163                                         g_free (rf);
5164                                 }
5165                         } else if (!strcmp (opt, "print-allowance")) {
5166                                 debug_print_allowance = TRUE;
5167                         } else if (!strcmp (opt, "print-pinning")) {
5168                                 do_pin_stats = TRUE;
5169                         } else if (!strcmp (opt, "verify-before-allocs")) {
5170                                 verify_before_allocs = 1;
5171                                 has_per_allocation_action = TRUE;
5172                         } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5173                                 char *arg = strchr (opt, '=') + 1;
5174                                 verify_before_allocs = atoi (arg);
5175                                 has_per_allocation_action = TRUE;
5176                         } else if (!strcmp (opt, "collect-before-allocs")) {
5177                                 collect_before_allocs = 1;
5178                                 has_per_allocation_action = TRUE;
5179                         } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5180                                 char *arg = strchr (opt, '=') + 1;
5181                                 has_per_allocation_action = TRUE;
5182                                 collect_before_allocs = atoi (arg);
5183                         } else if (!strcmp (opt, "verify-before-collections")) {
5184                                 whole_heap_check_before_collection = TRUE;
5185                         } else if (!strcmp (opt, "check-at-minor-collections")) {
5186                                 consistency_check_at_minor_collection = TRUE;
5187                                 nursery_clear_policy = CLEAR_AT_GC;
5188                         } else if (!strcmp (opt, "mod-union-consistency-check")) {
5189                                 if (!major_collector.is_concurrent) {
5190                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
5191                                         continue;
5192                                 }
5193                                 mod_union_consistency_check = TRUE;
5194                         } else if (!strcmp (opt, "check-mark-bits")) {
5195                                 check_mark_bits_after_major_collection = TRUE;
5196                         } else if (!strcmp (opt, "check-nursery-pinned")) {
5197                                 check_nursery_objects_pinned = TRUE;
5198                         } else if (!strcmp (opt, "xdomain-checks")) {
5199                                 xdomain_checks = TRUE;
5200                         } else if (!strcmp (opt, "clear-at-gc")) {
5201                                 nursery_clear_policy = CLEAR_AT_GC;
5202                         } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5203                                 nursery_clear_policy = CLEAR_AT_GC;
5204                         } else if (!strcmp (opt, "check-scan-starts")) {
5205                                 do_scan_starts_check = TRUE;
5206                         } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5207                                 do_verify_nursery = TRUE;
5208                         } else if (!strcmp (opt, "check-concurrent")) {
5209                                 if (!major_collector.is_concurrent) {
5210                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5211                                         continue;
5212                                 }
5213                                 do_concurrent_checks = TRUE;
5214                         } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5215                                 do_dump_nursery_content = TRUE;
5216                         } else if (!strcmp (opt, "no-managed-allocator")) {
5217                                 sgen_set_use_managed_allocator (FALSE);
5218                         } else if (!strcmp (opt, "disable-minor")) {
5219                                 disable_minor_collections = TRUE;
5220                         } else if (!strcmp (opt, "disable-major")) {
5221                                 disable_major_collections = TRUE;
5222                         } else if (g_str_has_prefix (opt, "heap-dump=")) {
5223                                 char *filename = strchr (opt, '=') + 1;
5224                                 nursery_clear_policy = CLEAR_AT_GC;
5225                                 heap_dump_file = fopen (filename, "w");
5226                                 if (heap_dump_file) {
5227                                         fprintf (heap_dump_file, "<sgen-dump>\n");
5228                                         do_pin_stats = TRUE;
5229                                 }
5230 #ifdef SGEN_BINARY_PROTOCOL
5231                         } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5232                                 char *filename = strchr (opt, '=') + 1;
5233                                 binary_protocol_init (filename);
5234 #endif
5235                         } else {
5236                                 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5237
5238                                 if (usage_printed)
5239                                         continue;
5240
5241                                 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);
5242                                 fprintf (stderr, "Valid <option>s are:\n");
5243                                 fprintf (stderr, "  collect-before-allocs[=<n>]\n");
5244                                 fprintf (stderr, "  verify-before-allocs[=<n>]\n");
5245                                 fprintf (stderr, "  check-at-minor-collections\n");
5246                                 fprintf (stderr, "  check-mark-bits\n");
5247                                 fprintf (stderr, "  check-nursery-pinned\n");
5248                                 fprintf (stderr, "  verify-before-collections\n");
5249                                 fprintf (stderr, "  verify-nursery-at-minor-gc\n");
5250                                 fprintf (stderr, "  dump-nursery-at-minor-gc\n");
5251                                 fprintf (stderr, "  disable-minor\n");
5252                                 fprintf (stderr, "  disable-major\n");
5253                                 fprintf (stderr, "  xdomain-checks\n");
5254                                 fprintf (stderr, "  check-concurrent\n");
5255                                 fprintf (stderr, "  clear-at-gc\n");
5256                                 fprintf (stderr, "  clear-nursery-at-gc\n");
5257                                 fprintf (stderr, "  check-scan-starts\n");
5258                                 fprintf (stderr, "  no-managed-allocator\n");
5259                                 fprintf (stderr, "  print-allowance\n");
5260                                 fprintf (stderr, "  print-pinning\n");
5261                                 fprintf (stderr, "  heap-dump=<filename>\n");
5262 #ifdef SGEN_BINARY_PROTOCOL
5263                                 fprintf (stderr, "  binary-protocol=<filename>\n");
5264 #endif
5265                                 fprintf (stderr, "\n");
5266
5267                                 usage_printed = TRUE;
5268                         }
5269                 }
5270                 g_strfreev (opts);
5271         }
5272
5273         if (major_collector.is_parallel) {
5274                 if (heap_dump_file) {
5275                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5276                         fclose (heap_dump_file);
5277                         heap_dump_file = NULL;
5278                 }
5279                 if (do_pin_stats) {
5280                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5281                         do_pin_stats = FALSE;
5282                 }
5283         }
5284
5285         if (major_collector.post_param_init)
5286                 major_collector.post_param_init (&major_collector);
5287
5288         sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5289
5290         memset (&remset, 0, sizeof (remset));
5291
5292         sgen_card_table_init (&remset);
5293
5294         gc_initialized = 1;
5295 }
5296
5297 const char *
5298 mono_gc_get_gc_name (void)
5299 {
5300         return "sgen";
5301 }
5302
5303 static MonoMethod *write_barrier_method;
5304
5305 gboolean
5306 sgen_is_critical_method (MonoMethod *method)
5307 {
5308         return (method == write_barrier_method || sgen_is_managed_allocator (method));
5309 }
5310
5311 gboolean
5312 sgen_has_critical_method (void)
5313 {
5314         return write_barrier_method || sgen_has_managed_allocator ();
5315 }
5316
5317 #ifndef DISABLE_JIT
5318
5319 static void
5320 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5321 {
5322         memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5323 #ifdef SGEN_ALIGN_NURSERY
5324         // if (ptr_in_nursery (ptr)) return;
5325         /*
5326          * Masking out the bits might be faster, but we would have to use 64 bit
5327          * immediates, which might be slower.
5328          */
5329         mono_mb_emit_ldarg (mb, 0);
5330         mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5331         mono_mb_emit_byte (mb, CEE_SHR_UN);
5332         mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5333         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5334
5335         if (!major_collector.is_concurrent) {
5336                 // if (!ptr_in_nursery (*ptr)) return;
5337                 mono_mb_emit_ldarg (mb, 0);
5338                 mono_mb_emit_byte (mb, CEE_LDIND_I);
5339                 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5340                 mono_mb_emit_byte (mb, CEE_SHR_UN);
5341                 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5342                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5343         }
5344 #else
5345         int label_continue1, label_continue2;
5346         int dereferenced_var;
5347
5348         // if (ptr < (sgen_get_nursery_start ())) goto continue;
5349         mono_mb_emit_ldarg (mb, 0);
5350         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5351         label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5352
5353         // if (ptr >= sgen_get_nursery_end ())) goto continue;
5354         mono_mb_emit_ldarg (mb, 0);
5355         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5356         label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5357
5358         // Otherwise return
5359         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5360
5361         // continue:
5362         mono_mb_patch_branch (mb, label_continue_1);
5363         mono_mb_patch_branch (mb, label_continue_2);
5364
5365         // Dereference and store in local var
5366         dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5367         mono_mb_emit_ldarg (mb, 0);
5368         mono_mb_emit_byte (mb, CEE_LDIND_I);
5369         mono_mb_emit_stloc (mb, dereferenced_var);
5370
5371         if (!major_collector.is_concurrent) {
5372                 // if (*ptr < sgen_get_nursery_start ()) return;
5373                 mono_mb_emit_ldloc (mb, dereferenced_var);
5374                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5375                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5376
5377                 // if (*ptr >= sgen_get_nursery_end ()) return;
5378                 mono_mb_emit_ldloc (mb, dereferenced_var);
5379                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5380                 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5381         }
5382 #endif
5383 }
5384 #endif
5385
5386 MonoMethod*
5387 mono_gc_get_write_barrier (void)
5388 {
5389         MonoMethod *res;
5390         MonoMethodBuilder *mb;
5391         MonoMethodSignature *sig;
5392 #ifdef MANAGED_WBARRIER
5393         int i, nursery_check_labels [3];
5394
5395 #ifdef HAVE_KW_THREAD
5396         int stack_end_offset = -1;
5397
5398         MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5399         g_assert (stack_end_offset != -1);
5400 #endif
5401 #endif
5402
5403         // FIXME: Maybe create a separate version for ctors (the branch would be
5404         // correctly predicted more times)
5405         if (write_barrier_method)
5406                 return write_barrier_method;
5407
5408         /* Create the IL version of mono_gc_barrier_generic_store () */
5409         sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5410         sig->ret = &mono_defaults.void_class->byval_arg;
5411         sig->params [0] = &mono_defaults.int_class->byval_arg;
5412
5413         mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5414
5415 #ifndef DISABLE_JIT
5416 #ifdef MANAGED_WBARRIER
5417         emit_nursery_check (mb, nursery_check_labels);
5418         /*
5419         addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5420         *addr = 1;
5421
5422         sgen_cardtable:
5423                 LDC_PTR sgen_cardtable
5424
5425         address >> CARD_BITS
5426                 LDARG_0
5427                 LDC_I4 CARD_BITS
5428                 SHR_UN
5429         if (SGEN_HAVE_OVERLAPPING_CARDS) {
5430                 LDC_PTR card_table_mask
5431                 AND
5432         }
5433         AND
5434         ldc_i4_1
5435         stind_i1
5436         */
5437         mono_mb_emit_ptr (mb, sgen_cardtable);
5438         mono_mb_emit_ldarg (mb, 0);
5439         mono_mb_emit_icon (mb, CARD_BITS);
5440         mono_mb_emit_byte (mb, CEE_SHR_UN);
5441 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5442         mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5443         mono_mb_emit_byte (mb, CEE_AND);
5444 #endif
5445         mono_mb_emit_byte (mb, CEE_ADD);
5446         mono_mb_emit_icon (mb, 1);
5447         mono_mb_emit_byte (mb, CEE_STIND_I1);
5448
5449         // return;
5450         for (i = 0; i < 3; ++i) {
5451                 if (nursery_check_labels [i])
5452                         mono_mb_patch_branch (mb, nursery_check_labels [i]);
5453         }
5454         mono_mb_emit_byte (mb, CEE_RET);
5455 #else
5456         mono_mb_emit_ldarg (mb, 0);
5457         mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5458         mono_mb_emit_byte (mb, CEE_RET);
5459 #endif
5460 #endif
5461         res = mono_mb_create_method (mb, sig, 16);
5462         mono_mb_free (mb);
5463
5464         mono_loader_lock ();
5465         if (write_barrier_method) {
5466                 /* Already created */
5467                 mono_free_method (res);
5468         } else {
5469                 /* double-checked locking */
5470                 mono_memory_barrier ();
5471                 write_barrier_method = res;
5472         }
5473         mono_loader_unlock ();
5474
5475         return write_barrier_method;
5476 }
5477
5478 char*
5479 mono_gc_get_description (void)
5480 {
5481         return g_strdup ("sgen");
5482 }
5483
5484 void
5485 mono_gc_set_desktop_mode (void)
5486 {
5487 }
5488
5489 gboolean
5490 mono_gc_is_moving (void)
5491 {
5492         return TRUE;
5493 }
5494
5495 gboolean
5496 mono_gc_is_disabled (void)
5497 {
5498         return FALSE;
5499 }
5500
5501 #ifdef HOST_WIN32
5502 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5503 {
5504         return TRUE;
5505 }
5506 #endif
5507
5508 NurseryClearPolicy
5509 sgen_get_nursery_clear_policy (void)
5510 {
5511         return nursery_clear_policy;
5512 }
5513
5514 MonoVTable*
5515 sgen_get_array_fill_vtable (void)
5516 {
5517         if (!array_fill_vtable) {
5518                 static MonoClass klass;
5519                 static MonoVTable vtable;
5520                 gsize bmap;
5521
5522                 MonoDomain *domain = mono_get_root_domain ();
5523                 g_assert (domain);
5524
5525                 klass.element_class = mono_defaults.byte_class;
5526                 klass.rank = 1;
5527                 klass.instance_size = sizeof (MonoArray);
5528                 klass.sizes.element_size = 1;
5529                 klass.name = "array_filler_type";
5530
5531                 vtable.klass = &klass;
5532                 bmap = 0;
5533                 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5534                 vtable.rank = 1;
5535
5536                 array_fill_vtable = &vtable;
5537         }
5538         return array_fill_vtable;
5539 }
5540
5541 void
5542 sgen_gc_lock (void)
5543 {
5544         LOCK_GC;
5545 }
5546
5547 void
5548 sgen_gc_unlock (void)
5549 {
5550         UNLOCK_GC;
5551 }
5552
5553 void
5554 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5555 {
5556         major_collector.iterate_live_block_ranges (callback);
5557 }
5558
5559 void
5560 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5561 {
5562         major_collector.scan_card_table (FALSE, queue);
5563 }
5564
5565 SgenMajorCollector*
5566 sgen_get_major_collector (void)
5567 {
5568         return &major_collector;
5569 }
5570
5571 void mono_gc_set_skip_thread (gboolean skip)
5572 {
5573         SgenThreadInfo *info = mono_thread_info_current ();
5574
5575         LOCK_GC;
5576         info->gc_disabled = skip;
5577         UNLOCK_GC;
5578 }
5579
5580 SgenRemeberedSet*
5581 sgen_get_remset (void)
5582 {
5583         return &remset;
5584 }
5585
5586 guint
5587 mono_gc_get_vtable_bits (MonoClass *class)
5588 {
5589         if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5590                 return SGEN_GC_BIT_BRIDGE_OBJECT;
5591         return 0;
5592 }
5593
5594 void
5595 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5596 {
5597         // FIXME:
5598 }
5599
5600
5601 void
5602 sgen_check_whole_heap_stw (void)
5603 {
5604         sgen_stop_world (0);
5605         sgen_clear_nursery_fragments ();
5606         sgen_check_whole_heap (FALSE);
5607         sgen_restart_world (0, NULL);
5608 }
5609
5610 void
5611 sgen_gc_event_moves (void)
5612 {
5613         if (moved_objects_idx) {
5614                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5615                 moved_objects_idx = 0;
5616         }
5617 }
5618
5619 #endif /* HAVE_SGEN_GC */