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, check whether mark bits are consistent after major collections */
 267 static gboolean check_mark_bits_after_major_collection = FALSE;
 268 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
 269 static gboolean check_nursery_objects_pinned = FALSE;
 270 /* If set, do a few checks when the concurrent collector is used */
 271 static gboolean do_concurrent_checks = FALSE;
 272 /* If set, check that there are no references to the domain left at domain unload */
 273 static gboolean xdomain_checks = FALSE;
 274 /* If not null, dump the heap after each collection into this file */
 275 static FILE *heap_dump_file = NULL;
 276 /* If set, mark stacks conservatively, even if precise marking is possible */
 277 static gboolean conservative_stack_mark = FALSE;
 278 /* If set, do a plausibility check on the scan_starts before and after
 279    each collection */
 280 static gboolean do_scan_starts_check = FALSE;
 281 /*
 282  * If the major collector is concurrent and this is FALSE, we will
 283  * never initiate a synchronous major collection, unless requested via
 284  * GC.Collect().
 285  */
 286 static gboolean allow_synchronous_major = TRUE;
 287 static gboolean nursery_collection_is_parallel = FALSE;
 288 static gboolean disable_minor_collections = FALSE;
 289 static gboolean disable_major_collections = FALSE;
 290 gboolean do_pin_stats = FALSE;
 291 static gboolean do_verify_nursery = FALSE;
 292 static gboolean do_dump_nursery_content = FALSE;
 293
 294 #ifdef HEAVY_STATISTICS
 295 long long stat_objects_alloced_degraded = 0;
 296 long long stat_bytes_alloced_degraded = 0;
 297
 298 long long stat_copy_object_called_nursery = 0;
 299 long long stat_objects_copied_nursery = 0;
 300 long long stat_copy_object_called_major = 0;
 301 long long stat_objects_copied_major = 0;
 302
 303 long long stat_scan_object_called_nursery = 0;
 304 long long stat_scan_object_called_major = 0;
 305
 306 long long stat_slots_allocated_in_vain;
 307
 308 long long stat_nursery_copy_object_failed_from_space = 0;
 309 long long stat_nursery_copy_object_failed_forwarded = 0;
 310 long long stat_nursery_copy_object_failed_pinned = 0;
 311 long long stat_nursery_copy_object_failed_to_space = 0;
 312
 313 static int stat_wbarrier_add_to_global_remset = 0;
 314 static int stat_wbarrier_set_field = 0;
 315 static int stat_wbarrier_set_arrayref = 0;
 316 static int stat_wbarrier_arrayref_copy = 0;
 317 static int stat_wbarrier_generic_store = 0;
 318 static int stat_wbarrier_set_root = 0;
 319 static int stat_wbarrier_value_copy = 0;
 320 static int stat_wbarrier_object_copy = 0;
 321 #endif
 322
 323 int stat_minor_gcs = 0;
 324 int stat_major_gcs = 0;
 325
 326 static long long stat_pinned_objects = 0;
 327
 328 static long long time_minor_pre_collection_fragment_clear = 0;
 329 static long long time_minor_pinning = 0;
 330 static long long time_minor_scan_remsets = 0;
 331 static long long time_minor_scan_pinned = 0;
 332 static long long time_minor_scan_registered_roots = 0;
 333 static long long time_minor_scan_thread_data = 0;
 334 static long long time_minor_finish_gray_stack = 0;
 335 static long long time_minor_fragment_creation = 0;
 336
 337 static long long time_major_pre_collection_fragment_clear = 0;
 338 static long long time_major_pinning = 0;
 339 static long long time_major_scan_pinned = 0;
 340 static long long time_major_scan_registered_roots = 0;
 341 static long long time_major_scan_thread_data = 0;
 342 static long long time_major_scan_alloc_pinned = 0;
 343 static long long time_major_scan_finalized = 0;
 344 static long long time_major_scan_big_objects = 0;
 345 static long long time_major_finish_gray_stack = 0;
 346 static long long time_major_free_bigobjs = 0;
 347 static long long time_major_los_sweep = 0;
 348 static long long time_major_sweep = 0;
 349 static long long time_major_fragment_creation = 0;
 350
 351 int gc_debug_level = 0;
 352 FILE* gc_debug_file;
 353
 354 /*
 355 void
 356 mono_gc_flush_info (void)
 357 {
 358         fflush (gc_debug_file);
 359 }
 360 */
 361
 362 #define TV_DECLARE SGEN_TV_DECLARE
 363 #define TV_GETTIME SGEN_TV_GETTIME
 364 #define TV_ELAPSED SGEN_TV_ELAPSED
 365 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
 366
 367 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
 368
 369 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
 370
 371 #define object_is_forwarded     SGEN_OBJECT_IS_FORWARDED
 372 #define object_is_pinned        SGEN_OBJECT_IS_PINNED
 373 #define pin_object              SGEN_PIN_OBJECT
 374 #define unpin_object            SGEN_UNPIN_OBJECT
 375
 376 #define ptr_in_nursery sgen_ptr_in_nursery
 377
 378 #define LOAD_VTABLE     SGEN_LOAD_VTABLE
 379
 380 static const char*
 381 safe_name (void* obj)
 382 {
 383         MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
 384         return vt->klass->name;
 385 }
 386
 387 #define safe_object_get_size    sgen_safe_object_get_size
 388
 389 const char*
 390 sgen_safe_name (void* obj)
 391 {
 392         return safe_name (obj);
 393 }
 394
 395 /*
 396  * ######################################################################
 397  * ########  Global data.
 398  * ######################################################################
 399  */
 400 LOCK_DECLARE (gc_mutex);
 401
 402 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
 403
 404 static mword pagesize = 4096;
 405 int degraded_mode = 0;
 406
 407 static mword bytes_pinned_from_failed_allocation = 0;
 408
 409 GCMemSection *nursery_section = NULL;
 410 static mword lowest_heap_address = ~(mword)0;
 411 static mword highest_heap_address = 0;
 412
 413 LOCK_DECLARE (sgen_interruption_mutex);
 414 static LOCK_DECLARE (pin_queue_mutex);
 415
 416 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
 417 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
 418
 419 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
 420 struct _FinalizeReadyEntry {
 421         FinalizeReadyEntry *next;
 422         void *object;
 423 };
 424
 425 typedef struct _EphemeronLinkNode EphemeronLinkNode;
 426
 427 struct _EphemeronLinkNode {
 428         EphemeronLinkNode *next;
 429         char *array;
 430 };
 431
 432 typedef struct {
 433        void *key;
 434        void *value;
 435 } Ephemeron;
 436
 437 int current_collection_generation = -1;
 438 volatile gboolean concurrent_collection_in_progress = FALSE;
 439
 440 /* objects that are ready to be finalized */
 441 static FinalizeReadyEntry *fin_ready_list = NULL;
 442 static FinalizeReadyEntry *critical_fin_list = NULL;
 443
 444 static EphemeronLinkNode *ephemeron_list;
 445
 446 /* registered roots: the key to the hash is the root start address */
 447 /*
 448  * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
 449  */
 450 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
 451         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 452         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 453         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
 454 };
 455 static mword roots_size = 0; /* amount of memory in the root set */
 456
 457 #define GC_ROOT_NUM 32
 458 typedef struct {
 459         int count;              /* must be the first field */
 460         void *objects [GC_ROOT_NUM];
 461         int root_types [GC_ROOT_NUM];
 462         uintptr_t extra_info [GC_ROOT_NUM];
 463 } GCRootReport;
 464
 465 static void
 466 notify_gc_roots (GCRootReport *report)
 467 {
 468         if (!report->count)
 469                 return;
 470         mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
 471         report->count = 0;
 472 }
 473
 474 static void
 475 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
 476 {
 477         if (report->count == GC_ROOT_NUM)
 478                 notify_gc_roots (report);
 479         report->objects [report->count] = object;
 480         report->root_types [report->count] = rtype;
 481         report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
 482 }
 483
 484 MonoNativeTlsKey thread_info_key;
 485
 486 #ifdef HAVE_KW_THREAD
 487 __thread SgenThreadInfo *sgen_thread_info;
 488 __thread char *stack_end;
 489 #endif
 490
 491 /* The size of a TLAB */
 492 /* The bigger the value, the less often we have to go to the slow path to allocate a new
 493  * one, but the more space is wasted by threads not allocating much memory.
 494  * FIXME: Tune this.
 495  * FIXME: Make this self-tuning for each thread.
 496  */
 497 guint32 tlab_size = (1024 * 4);
 498
 499 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
 500
 501 /* Functions supplied by the runtime to be called by the GC */
 502 static MonoGCCallbacks gc_callbacks;
 503
 504 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
 505 #define ALLOC_ALIGN_BITS        SGEN_ALLOC_ALIGN_BITS
 506
 507 #define ALIGN_UP                SGEN_ALIGN_UP
 508
 509 #define MOVED_OBJECTS_NUM 64
 510 static void *moved_objects [MOVED_OBJECTS_NUM];
 511 static int moved_objects_idx = 0;
 512
 513 /* Vtable of the objects used to fill out nursery fragments before a collection */
 514 static MonoVTable *array_fill_vtable;
 515
 516 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
 517 MonoNativeThreadId main_gc_thread = NULL;
 518 #endif
 519
 520 /*Object was pinned during the current collection*/
 521 static mword objects_pinned;
 522
 523 /*
 524  * ######################################################################
 525  * ########  Macros and function declarations.
 526  * ######################################################################
 527  */
 528
 529 inline static void*
 530 align_pointer (void *ptr)
 531 {
 532         mword p = (mword)ptr;
 533         p += sizeof (gpointer) - 1;
 534         p &= ~ (sizeof (gpointer) - 1);
 535         return (void*)p;
 536 }
 537
 538 typedef SgenGrayQueue GrayQueue;
 539
 540 /* forward declarations */
 541 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
 542 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
 543 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
 544 static void report_finalizer_roots (void);
 545 static void report_registered_roots (void);
 546
 547 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
 548 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
 549 static void finish_gray_stack (int generation, GrayQueue *queue);
 550
 551 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
 552
 553
 554 static void init_stats (void);
 555
 556 static int mark_ephemerons_in_range (ScanCopyContext ctx);
 557 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
 558 static void null_ephemerons_for_domain (MonoDomain *domain);
 559
 560 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
 561
 562 SgenObjectOperations current_object_ops;
 563 SgenMajorCollector major_collector;
 564 SgenMinorCollector sgen_minor_collector;
 565 static GrayQueue gray_queue;
 566
 567 static SgenRemeberedSet remset;
 568
 569 /* The gray queue to use from the main collection thread. */
 570 #define WORKERS_DISTRIBUTE_GRAY_QUEUE   (&gray_queue)
 571
 572 /*
 573  * The gray queue a worker job must use.  If we're not parallel or
 574  * concurrent, we use the main gray queue.
 575  */
 576 static SgenGrayQueue*
 577 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
 578 {
 579         return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
 580 }
 581
 582 static void
 583 gray_queue_redirect (SgenGrayQueue *queue)
 584 {
 585         gboolean wake = FALSE;
 586
 587
 588         for (;;) {
 589                 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
 590                 if (!section)
 591                         break;
 592                 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
 593                 wake = TRUE;
 594         }
 595
 596         if (wake) {
 597                 g_assert (concurrent_collection_in_progress ||
 598                                 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
 599                 if (sgen_workers_have_started ()) {
 600                         sgen_workers_wake_up_all ();
 601                 } else {
 602                         if (concurrent_collection_in_progress)
 603                                 g_assert (current_collection_generation == -1);
 604                 }
 605         }
 606 }
 607
 608 static gboolean
 609 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
 610 {
 611         MonoObject *o = (MonoObject*)(obj);
 612         MonoObject *ref = (MonoObject*)*(ptr);
 613         int offset = (char*)(ptr) - (char*)o;
 614
 615         if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
 616                 return TRUE;
 617         if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
 618                 return TRUE;
 619
 620 #ifndef DISABLE_REMOTING
 621         if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
 622                         offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
 623                 return TRUE;
 624 #endif
 625         /* Thread.cached_culture_info */
 626         if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
 627                         !strcmp (ref->vtable->klass->name, "CultureInfo") &&
 628                         !strcmp(o->vtable->klass->name_space, "System") &&
 629                         !strcmp(o->vtable->klass->name, "Object[]"))
 630                 return TRUE;
 631         /*
 632          *  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
 633          * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
 634          * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
 635          * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
 636          * 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
 637          * 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
 638          * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
 639          * 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
 640          * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
 641          */
 642         if (!strcmp (ref->vtable->klass->name_space, "System") &&
 643                         !strcmp (ref->vtable->klass->name, "Byte[]") &&
 644                         !strcmp (o->vtable->klass->name_space, "System.IO") &&
 645                         !strcmp (o->vtable->klass->name, "MemoryStream"))
 646                 return TRUE;
 647         /* append_job() in threadpool.c */
 648         if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
 649                         !strcmp (ref->vtable->klass->name, "AsyncResult") &&
 650                         !strcmp (o->vtable->klass->name_space, "System") &&
 651                         !strcmp (o->vtable->klass->name, "Object[]") &&
 652                         mono_thread_pool_is_queue_array ((MonoArray*) o))
 653                 return TRUE;
 654         return FALSE;
 655 }
 656
 657 static void
 658 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
 659 {
 660         MonoObject *o = (MonoObject*)(obj);
 661         MonoObject *ref = (MonoObject*)*(ptr);
 662         int offset = (char*)(ptr) - (char*)o;
 663         MonoClass *class;
 664         MonoClassField *field;
 665         char *str;
 666
 667         if (!ref || ref->vtable->domain == domain)
 668                 return;
 669         if (is_xdomain_ref_allowed (ptr, obj, domain))
 670                 return;
 671
 672         field = NULL;
 673         for (class = o->vtable->klass; class; class = class->parent) {
 674                 int i;
 675
 676                 for (i = 0; i < class->field.count; ++i) {
 677                         if (class->fields[i].offset == offset) {
 678                                 field = &class->fields[i];
 679                                 break;
 680                         }
 681                 }
 682                 if (field)
 683                         break;
 684         }
 685
 686         if (ref->vtable->klass == mono_defaults.string_class)
 687                 str = mono_string_to_utf8 ((MonoString*)ref);
 688         else
 689                 str = NULL;
 690         g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s)  -  pointed to by:\n",
 691                         o, o->vtable->klass->name_space, o->vtable->klass->name,
 692                         offset, field ? field->name : "",
 693                         ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
 694         mono_gc_scan_for_specific_ref (o, TRUE);
 695         if (str)
 696                 g_free (str);
 697 }
 698
 699 #undef HANDLE_PTR
 700 #define HANDLE_PTR(ptr,obj)     check_reference_for_xdomain ((ptr), (obj), domain)
 701
 702 static void
 703 scan_object_for_xdomain_refs (char *start, mword size, void *data)
 704 {
 705         MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
 706
 707         #include "sgen-scan-object.h"
 708 }
 709
 710 static gboolean scan_object_for_specific_ref_precise = TRUE;
 711
 712 #undef HANDLE_PTR
 713 #define HANDLE_PTR(ptr,obj) do {                \
 714         if ((MonoObject*)*(ptr) == key) {       \
 715         g_print ("found ref to %p in object %p (%s) at offset %td\n",   \
 716                         key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
 717         }                                                               \
 718         } while (0)
 719
 720 static void
 721 scan_object_for_specific_ref (char *start, MonoObject *key)
 722 {
 723         char *forwarded;
 724
 725         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
 726                 start = forwarded;
 727
 728         if (scan_object_for_specific_ref_precise) {
 729                 #include "sgen-scan-object.h"
 730         } else {
 731                 mword *words = (mword*)start;
 732                 size_t size = safe_object_get_size ((MonoObject*)start);
 733                 int i;
 734                 for (i = 0; i < size / sizeof (mword); ++i) {
 735                         if (words [i] == (mword)key) {
 736                                 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
 737                                                 key, start, safe_name (start), i * sizeof (mword));
 738                         }
 739                 }
 740         }
 741 }
 742
 743 void
 744 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
 745 {
 746         while (start < end) {
 747                 size_t size;
 748                 char *obj;
 749
 750                 if (!*(void**)start) {
 751                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
 752                         continue;
 753                 }
 754
 755                 if (allow_flags) {
 756                         if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
 757                                 obj = start;
 758                 } else {
 759                         obj = start;
 760                 }
 761
 762                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
 763
 764                 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
 765                         callback (obj, size, data);
 766
 767                 start += size;
 768         }
 769 }
 770
 771 static void
 772 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
 773 {
 774         scan_object_for_specific_ref (obj, key);
 775 }
 776
 777 static void
 778 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
 779 {
 780         if (key != obj)
 781                 return;
 782         g_print ("found ref to %p in root record %p\n", key, root);
 783 }
 784
 785 static MonoObject *check_key = NULL;
 786 static RootRecord *check_root = NULL;
 787
 788 static void
 789 check_root_obj_specific_ref_from_marker (void **obj)
 790 {
 791         check_root_obj_specific_ref (check_root, check_key, *obj);
 792 }
 793
 794 static void
 795 scan_roots_for_specific_ref (MonoObject *key, int root_type)
 796 {
 797         void **start_root;
 798         RootRecord *root;
 799         check_key = key;
 800
 801         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 802                 mword desc = root->root_desc;
 803
 804                 check_root = root;
 805
 806                 switch (desc & ROOT_DESC_TYPE_MASK) {
 807                 case ROOT_DESC_BITMAP:
 808                         desc >>= ROOT_DESC_TYPE_SHIFT;
 809                         while (desc) {
 810                                 if (desc & 1)
 811                                         check_root_obj_specific_ref (root, key, *start_root);
 812                                 desc >>= 1;
 813                                 start_root++;
 814                         }
 815                         return;
 816                 case ROOT_DESC_COMPLEX: {
 817                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 818                         int bwords = (*bitmap_data) - 1;
 819                         void **start_run = start_root;
 820                         bitmap_data++;
 821                         while (bwords-- > 0) {
 822                                 gsize bmap = *bitmap_data++;
 823                                 void **objptr = start_run;
 824                                 while (bmap) {
 825                                         if (bmap & 1)
 826                                                 check_root_obj_specific_ref (root, key, *objptr);
 827                                         bmap >>= 1;
 828                                         ++objptr;
 829                                 }
 830                                 start_run += GC_BITS_PER_WORD;
 831                         }
 832                         break;
 833                 }
 834                 case ROOT_DESC_USER: {
 835                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 836                         marker (start_root, check_root_obj_specific_ref_from_marker);
 837                         break;
 838                 }
 839                 case ROOT_DESC_RUN_LEN:
 840                         g_assert_not_reached ();
 841                 default:
 842                         g_assert_not_reached ();
 843                 }
 844         } SGEN_HASH_TABLE_FOREACH_END;
 845
 846         check_key = NULL;
 847         check_root = NULL;
 848 }
 849
 850 void
 851 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
 852 {
 853         void **ptr;
 854         RootRecord *root;
 855
 856         scan_object_for_specific_ref_precise = precise;
 857
 858         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 859                         (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
 860
 861         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 862
 863         sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 864
 865         scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
 866         scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
 867
 868         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
 869                 while (ptr < (void**)root->end_root) {
 870                         check_root_obj_specific_ref (root, *ptr, key);
 871                         ++ptr;
 872                 }
 873         } SGEN_HASH_TABLE_FOREACH_END;
 874 }
 875
 876 static gboolean
 877 need_remove_object_for_domain (char *start, MonoDomain *domain)
 878 {
 879         if (mono_object_domain (start) == domain) {
 880                 SGEN_LOG (4, "Need to cleanup object %p", start);
 881                 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
 882                 return TRUE;
 883         }
 884         return FALSE;
 885 }
 886
 887 static void
 888 process_object_for_domain_clearing (char *start, MonoDomain *domain)
 889 {
 890         GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
 891         if (vt->klass == mono_defaults.internal_thread_class)
 892                 g_assert (mono_object_domain (start) == mono_get_root_domain ());
 893         /* The object could be a proxy for an object in the domain
 894            we're deleting. */
 895 #ifndef DISABLE_REMOTING
 896         if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
 897                 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
 898
 899                 /* The server could already have been zeroed out, so
 900                    we need to check for that, too. */
 901                 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
 902                         SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
 903                         ((MonoRealProxy*)start)->unwrapped_server = NULL;
 904                 }
 905         }
 906 #endif
 907 }
 908
 909 static MonoDomain *check_domain = NULL;
 910
 911 static void
 912 check_obj_not_in_domain (void **o)
 913 {
 914         g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
 915 }
 916
 917 static void
 918 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
 919 {
 920         void **start_root;
 921         RootRecord *root;
 922         check_domain = domain;
 923         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 924                 mword desc = root->root_desc;
 925
 926                 /* The MonoDomain struct is allowed to hold
 927                    references to objects in its own domain. */
 928                 if (start_root == (void**)domain)
 929                         continue;
 930
 931                 switch (desc & ROOT_DESC_TYPE_MASK) {
 932                 case ROOT_DESC_BITMAP:
 933                         desc >>= ROOT_DESC_TYPE_SHIFT;
 934                         while (desc) {
 935                                 if ((desc & 1) && *start_root)
 936                                         check_obj_not_in_domain (*start_root);
 937                                 desc >>= 1;
 938                                 start_root++;
 939                         }
 940                         break;
 941                 case ROOT_DESC_COMPLEX: {
 942                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 943                         int bwords = (*bitmap_data) - 1;
 944                         void **start_run = start_root;
 945                         bitmap_data++;
 946                         while (bwords-- > 0) {
 947                                 gsize bmap = *bitmap_data++;
 948                                 void **objptr = start_run;
 949                                 while (bmap) {
 950                                         if ((bmap & 1) && *objptr)
 951                                                 check_obj_not_in_domain (*objptr);
 952                                         bmap >>= 1;
 953                                         ++objptr;
 954                                 }
 955                                 start_run += GC_BITS_PER_WORD;
 956                         }
 957                         break;
 958                 }
 959                 case ROOT_DESC_USER: {
 960                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 961                         marker (start_root, check_obj_not_in_domain);
 962                         break;
 963                 }
 964                 case ROOT_DESC_RUN_LEN:
 965                         g_assert_not_reached ();
 966                 default:
 967                         g_assert_not_reached ();
 968                 }
 969         } SGEN_HASH_TABLE_FOREACH_END;
 970
 971         check_domain = NULL;
 972 }
 973
 974 static void
 975 check_for_xdomain_refs (void)
 976 {
 977         LOSObject *bigobj;
 978
 979         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 980                         (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
 981
 982         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
 983
 984         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
 985                 scan_object_for_xdomain_refs (bigobj->data, sgen_los_object_size (bigobj), NULL);
 986 }
 987
 988 static gboolean
 989 clear_domain_process_object (char *obj, MonoDomain *domain)
 990 {
 991         gboolean remove;
 992
 993         process_object_for_domain_clearing (obj, domain);
 994         remove = need_remove_object_for_domain (obj, domain);
 995
 996         if (remove && ((MonoObject*)obj)->synchronisation) {
 997                 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
 998                 if (dislink)
 999                         sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
1000         }
1001
1002         return remove;
1003 }
1004
1005 static void
1006 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1007 {
1008         if (clear_domain_process_object (obj, domain))
1009                 memset (obj, 0, size);
1010 }
1011
1012 static void
1013 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1014 {
1015         clear_domain_process_object (obj, domain);
1016 }
1017
1018 static void
1019 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1020 {
1021         if (need_remove_object_for_domain (obj, domain))
1022                 major_collector.free_non_pinned_object (obj, size);
1023 }
1024
1025 static void
1026 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1027 {
1028         if (need_remove_object_for_domain (obj, domain))
1029                 major_collector.free_pinned_object (obj, size);
1030 }
1031
1032 /*
1033  * When appdomains are unloaded we can easily remove objects that have finalizers,
1034  * but all the others could still be present in random places on the heap.
1035  * We need a sweep to get rid of them even though it's going to be costly
1036  * with big heaps.
1037  * The reason we need to remove them is because we access the vtable and class
1038  * structures to know the object size and the reference bitmap: once the domain is
1039  * unloaded the point to random memory.
1040  */
1041 void
1042 mono_gc_clear_domain (MonoDomain * domain)
1043 {
1044         LOSObject *bigobj, *prev;
1045         int i;
1046
1047         LOCK_GC;
1048
1049         if (concurrent_collection_in_progress)
1050                 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
1051         g_assert (!concurrent_collection_in_progress);
1052
1053         sgen_process_fin_stage_entries ();
1054         sgen_process_dislink_stage_entries ();
1055
1056         sgen_clear_nursery_fragments ();
1057
1058         if (xdomain_checks && domain != mono_get_root_domain ()) {
1059                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1060                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1061                 check_for_xdomain_refs ();
1062         }
1063
1064         /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1065         to memory returned to the OS.*/
1066         null_ephemerons_for_domain (domain);
1067
1068         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1069                 sgen_null_links_for_domain (domain, i);
1070
1071         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1072                 sgen_remove_finalizers_for_domain (domain, i);
1073
1074         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1075                         (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1076
1077         /* We need two passes over major and large objects because
1078            freeing such objects might give their memory back to the OS
1079            (in the case of large objects) or obliterate its vtable
1080            (pinned objects with major-copying or pinned and non-pinned
1081            objects with major-mark&sweep), but we might need to
1082            dereference a pointer from an object to another object if
1083            the first object is a proxy. */
1084         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1085         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1086                 clear_domain_process_object (bigobj->data, domain);
1087
1088         prev = NULL;
1089         for (bigobj = los_object_list; bigobj;) {
1090                 if (need_remove_object_for_domain (bigobj->data, domain)) {
1091                         LOSObject *to_free = bigobj;
1092                         if (prev)
1093                                 prev->next = bigobj->next;
1094                         else
1095                                 los_object_list = bigobj->next;
1096                         bigobj = bigobj->next;
1097                         SGEN_LOG (4, "Freeing large object %p", bigobj->data);
1098                         sgen_los_free_object (to_free);
1099                         continue;
1100                 }
1101                 prev = bigobj;
1102                 bigobj = bigobj->next;
1103         }
1104         major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1105         major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1106
1107         if (domain == mono_get_root_domain ()) {
1108                 if (G_UNLIKELY (do_pin_stats))
1109                         sgen_pin_stats_print_class_stats ();
1110                 sgen_object_layout_dump (stdout);
1111         }
1112
1113         UNLOCK_GC;
1114 }
1115
1116 /*
1117  * sgen_add_to_global_remset:
1118  *
1119  *   The global remset contains locations which point into newspace after
1120  * a minor collection. This can happen if the objects they point to are pinned.
1121  *
1122  * LOCKING: If called from a parallel collector, the global remset
1123  * lock must be held.  For serial collectors that is not necessary.
1124  */
1125 void
1126 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
1127 {
1128         SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
1129
1130         HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
1131
1132         if (!major_collector.is_concurrent) {
1133                 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
1134         } else {
1135                 if (current_collection_generation == -1)
1136                         SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
1137         }
1138
1139         if (!object_is_pinned (obj))
1140                 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");
1141         else if (sgen_cement_lookup_or_register (obj))
1142                 return;
1143
1144         remset.record_pointer (ptr);
1145
1146         if (G_UNLIKELY (do_pin_stats))
1147                 sgen_pin_stats_register_global_remset (obj);
1148
1149         SGEN_LOG (8, "Adding global remset for %p", ptr);
1150         binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
1151
1152
1153 #ifdef ENABLE_DTRACE
1154         if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
1155                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
1156                 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
1157                                 vt->klass->name_space, vt->klass->name);
1158         }
1159 #endif
1160 }
1161
1162 /*
1163  * sgen_drain_gray_stack:
1164  *
1165  *   Scan objects in the gray stack until the stack is empty. This should be called
1166  * frequently after each object is copied, to achieve better locality and cache
1167  * usage.
1168  */
1169 gboolean
1170 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
1171 {
1172         char *obj;
1173         ScanObjectFunc scan_func = ctx.scan_func;
1174         GrayQueue *queue = ctx.queue;
1175
1176         if (max_objs == -1) {
1177                 for (;;) {
1178                         GRAY_OBJECT_DEQUEUE (queue, obj);
1179                         if (!obj)
1180                                 return TRUE;
1181                         SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1182                         scan_func (obj, queue);
1183                 }
1184         } else {
1185                 int i;
1186
1187                 do {
1188                         for (i = 0; i != max_objs; ++i) {
1189                                 GRAY_OBJECT_DEQUEUE (queue, obj);
1190                                 if (!obj)
1191                                         return TRUE;
1192                                 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1193                                 scan_func (obj, queue);
1194                         }
1195                 } while (max_objs < 0);
1196                 return FALSE;
1197         }
1198 }
1199
1200 /*
1201  * Addresses from start to end are already sorted. This function finds
1202  * the object header for each address and pins the object. The
1203  * addresses must be inside the passed section.  The (start of the)
1204  * address array is overwritten with the addresses of the actually
1205  * pinned objects.  Return the number of pinned objects.
1206  */
1207 static int
1208 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1209 {
1210         void *last = NULL;
1211         int count = 0;
1212         void *search_start;
1213         void *last_obj = NULL;
1214         size_t last_obj_size = 0;
1215         void *addr;
1216         int idx;
1217         void **definitely_pinned = start;
1218         ScanObjectFunc scan_func = ctx.scan_func;
1219         SgenGrayQueue *queue = ctx.queue;
1220
1221         sgen_nursery_allocator_prepare_for_pinning ();
1222
1223         while (start < end) {
1224                 addr = *start;
1225                 /* the range check should be reduntant */
1226                 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1227                         SGEN_LOG (5, "Considering pinning addr %p", addr);
1228                         /* multiple pointers to the same object */
1229                         if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1230                                 start++;
1231                                 continue;
1232                         }
1233                         idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1234                         g_assert (idx < section->num_scan_start);
1235                         search_start = (void*)section->scan_starts [idx];
1236                         if (!search_start || search_start > addr) {
1237                                 while (idx) {
1238                                         --idx;
1239                                         search_start = section->scan_starts [idx];
1240                                         if (search_start && search_start <= addr)
1241                                                 break;
1242                                 }
1243                                 if (!search_start || search_start > addr)
1244                                         search_start = start_nursery;
1245                         }
1246                         if (search_start < last_obj)
1247                                 search_start = (char*)last_obj + last_obj_size;
1248                         /* now addr should be in an object a short distance from search_start
1249                          * Note that search_start must point to zeroed mem or point to an object.
1250                          */
1251
1252                         do {
1253                                 if (!*(void**)search_start) {
1254                                         /* Consistency check */
1255                                         /*
1256                                         for (frag = nursery_fragments; frag; frag = frag->next) {
1257                                                 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1258                                                         g_assert_not_reached ();
1259                                         }
1260                                         */
1261
1262                                         search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1263                                         continue;
1264                                 }
1265                                 last_obj = search_start;
1266                                 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1267
1268                                 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1269                                         /* Marks the beginning of a nursery fragment, skip */
1270                                 } else {
1271                                         SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
1272                                         if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1273                                                 if (scan_func) {
1274                                                         scan_func (search_start, queue);
1275                                                 } else {
1276                                                         SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1277                                                                         search_start, *(void**)search_start, safe_name (search_start), count);
1278                                                         binary_protocol_pin (search_start,
1279                                                                         (gpointer)LOAD_VTABLE (search_start),
1280                                                                         safe_object_get_size (search_start));
1281
1282 #ifdef ENABLE_DTRACE
1283                                                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1284                                                                 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
1285                                                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
1286                                                                 MONO_GC_OBJ_PINNED ((mword)search_start,
1287                                                                                 sgen_safe_object_get_size (search_start),
1288                                                                                 vt->klass->name_space, vt->klass->name, gen);
1289                                                         }
1290 #endif
1291
1292                                                         pin_object (search_start);
1293                                                         GRAY_OBJECT_ENQUEUE (queue, search_start);
1294                                                         if (G_UNLIKELY (do_pin_stats))
1295                                                                 sgen_pin_stats_register_object (search_start, last_obj_size);
1296                                                         definitely_pinned [count] = search_start;
1297                                                         count++;
1298                                                 }
1299                                                 break;
1300                                         }
1301                                 }
1302                                 /* skip to the next object */
1303                                 search_start = (void*)((char*)search_start + last_obj_size);
1304                         } while (search_start <= addr);
1305                         /* we either pinned the correct object or we ignored the addr because
1306                          * it points to unused zeroed memory.
1307                          */
1308                         last = addr;
1309                 }
1310                 start++;
1311         }
1312         //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1313         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1314                 GCRootReport report;
1315                 report.count = 0;
1316                 for (idx = 0; idx < count; ++idx)
1317                         add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1318                 notify_gc_roots (&report);
1319         }
1320         stat_pinned_objects += count;
1321         return count;
1322 }
1323
1324 void
1325 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1326 {
1327         int num_entries = section->pin_queue_num_entries;
1328         if (num_entries) {
1329                 void **start = section->pin_queue_start;
1330                 int reduced_to;
1331                 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1332                                 section->data, section->next_data, ctx);
1333                 section->pin_queue_num_entries = reduced_to;
1334                 if (!reduced_to)
1335                         section->pin_queue_start = NULL;
1336         }
1337 }
1338
1339
1340 void
1341 sgen_pin_object (void *object, GrayQueue *queue)
1342 {
1343         g_assert (!concurrent_collection_in_progress);
1344
1345         if (sgen_collection_is_parallel ()) {
1346                 LOCK_PIN_QUEUE;
1347                 /*object arrives pinned*/
1348                 sgen_pin_stage_ptr (object);
1349                 ++objects_pinned ;
1350                 UNLOCK_PIN_QUEUE;
1351         } else {
1352                 SGEN_PIN_OBJECT (object);
1353                 sgen_pin_stage_ptr (object);
1354                 ++objects_pinned;
1355                 if (G_UNLIKELY (do_pin_stats))
1356                         sgen_pin_stats_register_object (object, safe_object_get_size (object));
1357         }
1358         GRAY_OBJECT_ENQUEUE (queue, object);
1359         binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1360
1361 #ifdef ENABLE_DTRACE
1362         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1363                 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1364                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1365                 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1366         }
1367 #endif
1368 }
1369
1370 void
1371 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1372 {
1373         for (;;) {
1374                 mword vtable_word;
1375                 gboolean major_pinned = FALSE;
1376
1377                 if (sgen_ptr_in_nursery (obj)) {
1378                         if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1379                                 sgen_pin_object (obj, queue);
1380                                 break;
1381                         }
1382                 } else {
1383                         major_collector.pin_major_object (obj, queue);
1384                         major_pinned = TRUE;
1385                 }
1386
1387                 vtable_word = *(mword*)obj;
1388                 /*someone else forwarded it, update the pointer and bail out*/
1389                 if (vtable_word & SGEN_FORWARDED_BIT) {
1390                         *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1391                         break;
1392                 }
1393
1394                 /*someone pinned it, nothing to do.*/
1395                 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1396                         break;
1397         }
1398 }
1399
1400 /* Sort the addresses in array in increasing order.
1401  * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1402  */
1403 void
1404 sgen_sort_addresses (void **array, int size)
1405 {
1406         int i;
1407         void *tmp;
1408
1409         for (i = 1; i < size; ++i) {
1410                 int child = i;
1411                 while (child > 0) {
1412                         int parent = (child - 1) / 2;
1413
1414                         if (array [parent] >= array [child])
1415                                 break;
1416
1417                         tmp = array [parent];
1418                         array [parent] = array [child];
1419                         array [child] = tmp;
1420
1421                         child = parent;
1422                 }
1423         }
1424
1425         for (i = size - 1; i > 0; --i) {
1426                 int end, root;
1427                 tmp = array [i];
1428                 array [i] = array [0];
1429                 array [0] = tmp;
1430
1431                 end = i - 1;
1432                 root = 0;
1433
1434                 while (root * 2 + 1 <= end) {
1435                         int child = root * 2 + 1;
1436
1437                         if (child < end && array [child] < array [child + 1])
1438                                 ++child;
1439                         if (array [root] >= array [child])
1440                                 break;
1441
1442                         tmp = array [root];
1443                         array [root] = array [child];
1444                         array [child] = tmp;
1445
1446                         root = child;
1447                 }
1448         }
1449 }
1450
1451 /*
1452  * Scan the memory between start and end and queue values which could be pointers
1453  * to the area between start_nursery and end_nursery for later consideration.
1454  * Typically used for thread stacks.
1455  */
1456 static void
1457 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1458 {
1459         int count = 0;
1460
1461 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1462         VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1463 #endif
1464
1465         while (start < end) {
1466                 if (*start >= start_nursery && *start < end_nursery) {
1467                         /*
1468                          * *start can point to the middle of an object
1469                          * note: should we handle pointing at the end of an object?
1470                          * pinning in C# code disallows pointing at the end of an object
1471                          * but there is some small chance that an optimizing C compiler
1472                          * may keep the only reference to an object by pointing
1473                          * at the end of it. We ignore this small chance for now.
1474                          * Pointers to the end of an object are indistinguishable
1475                          * from pointers to the start of the next object in memory
1476                          * so if we allow that we'd need to pin two objects...
1477                          * We queue the pointer in an array, the
1478                          * array will then be sorted and uniqued. This way
1479                          * we can coalesce several pinning pointers and it should
1480                          * be faster since we'd do a memory scan with increasing
1481                          * addresses. Note: we can align the address to the allocation
1482                          * alignment, so the unique process is more effective.
1483                          */
1484                         mword addr = (mword)*start;
1485                         addr &= ~(ALLOC_ALIGN - 1);
1486                         if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1487                                 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1488                                 sgen_pin_stage_ptr ((void*)addr);
1489                                 count++;
1490                         }
1491                         if (G_UNLIKELY (do_pin_stats)) {
1492                                 if (ptr_in_nursery ((void*)addr))
1493                                         sgen_pin_stats_register_address ((char*)addr, pin_type);
1494                         }
1495                 }
1496                 start++;
1497         }
1498         if (count)
1499                 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1500 }
1501
1502 /*
1503  * The first thing we do in a collection is to identify pinned objects.
1504  * This function considers all the areas of memory that need to be
1505  * conservatively scanned.
1506  */
1507 static void
1508 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1509 {
1510         void **start_root;
1511         RootRecord *root;
1512         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);
1513         /* objects pinned from the API are inside these roots */
1514         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1515                 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1516                 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1517         } SGEN_HASH_TABLE_FOREACH_END;
1518         /* now deal with the thread stacks
1519          * in the future we should be able to conservatively scan only:
1520          * *) the cpu registers
1521          * *) the unmanaged stack frames
1522          * *) the _last_ managed stack frame
1523          * *) pointers slots in managed frames
1524          */
1525         scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1526 }
1527
1528 static void
1529 unpin_objects_from_queue (SgenGrayQueue *queue)
1530 {
1531         for (;;) {
1532                 char *addr;
1533                 GRAY_OBJECT_DEQUEUE (queue, addr);
1534                 if (!addr)
1535                         break;
1536                 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1537                 SGEN_UNPIN_OBJECT (addr);
1538         }
1539 }
1540
1541 typedef struct {
1542         CopyOrMarkObjectFunc func;
1543         GrayQueue *queue;
1544 } UserCopyOrMarkData;
1545
1546 static MonoNativeTlsKey user_copy_or_mark_key;
1547
1548 static void
1549 init_user_copy_or_mark_key (void)
1550 {
1551         mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1552 }
1553
1554 static void
1555 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1556 {
1557         mono_native_tls_set_value (user_copy_or_mark_key, data);
1558 }
1559
1560 static void
1561 single_arg_user_copy_or_mark (void **obj)
1562 {
1563         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1564
1565         data->func (obj, data->queue);
1566 }
1567
1568 /*
1569  * The memory area from start_root to end_root contains pointers to objects.
1570  * Their position is precisely described by @desc (this means that the pointer
1571  * can be either NULL or the pointer to the start of an object).
1572  * This functions copies them to to_space updates them.
1573  *
1574  * This function is not thread-safe!
1575  */
1576 static void
1577 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1578 {
1579         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1580         SgenGrayQueue *queue = ctx.queue;
1581
1582         switch (desc & ROOT_DESC_TYPE_MASK) {
1583         case ROOT_DESC_BITMAP:
1584                 desc >>= ROOT_DESC_TYPE_SHIFT;
1585                 while (desc) {
1586                         if ((desc & 1) && *start_root) {
1587                                 copy_func (start_root, queue);
1588                                 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1589                                 sgen_drain_gray_stack (-1, ctx);
1590                         }
1591                         desc >>= 1;
1592                         start_root++;
1593                 }
1594                 return;
1595         case ROOT_DESC_COMPLEX: {
1596                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1597                 int bwords = (*bitmap_data) - 1;
1598                 void **start_run = start_root;
1599                 bitmap_data++;
1600                 while (bwords-- > 0) {
1601                         gsize bmap = *bitmap_data++;
1602                         void **objptr = start_run;
1603                         while (bmap) {
1604                                 if ((bmap & 1) && *objptr) {
1605                                         copy_func (objptr, queue);
1606                                         SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1607                                         sgen_drain_gray_stack (-1, ctx);
1608                                 }
1609                                 bmap >>= 1;
1610                                 ++objptr;
1611                         }
1612                         start_run += GC_BITS_PER_WORD;
1613                 }
1614                 break;
1615         }
1616         case ROOT_DESC_USER: {
1617                 UserCopyOrMarkData data = { copy_func, queue };
1618                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1619                 set_user_copy_or_mark_data (&data);
1620                 marker (start_root, single_arg_user_copy_or_mark);
1621                 set_user_copy_or_mark_data (NULL);
1622                 break;
1623         }
1624         case ROOT_DESC_RUN_LEN:
1625                 g_assert_not_reached ();
1626         default:
1627                 g_assert_not_reached ();
1628         }
1629 }
1630
1631 static void
1632 reset_heap_boundaries (void)
1633 {
1634         lowest_heap_address = ~(mword)0;
1635         highest_heap_address = 0;
1636 }
1637
1638 void
1639 sgen_update_heap_boundaries (mword low, mword high)
1640 {
1641         mword old;
1642
1643         do {
1644                 old = lowest_heap_address;
1645                 if (low >= old)
1646                         break;
1647         } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1648
1649         do {
1650                 old = highest_heap_address;
1651                 if (high <= old)
1652                         break;
1653         } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1654 }
1655
1656 /*
1657  * Allocate and setup the data structures needed to be able to allocate objects
1658  * in the nursery. The nursery is stored in nursery_section.
1659  */
1660 static void
1661 alloc_nursery (void)
1662 {
1663         GCMemSection *section;
1664         char *data;
1665         int scan_starts;
1666         int alloc_size;
1667
1668         if (nursery_section)
1669                 return;
1670         SGEN_LOG (2, "Allocating nursery size: %lu", (unsigned long)sgen_nursery_size);
1671         /* later we will alloc a larger area for the nursery but only activate
1672          * what we need. The rest will be used as expansion if we have too many pinned
1673          * objects in the existing nursery.
1674          */
1675         /* FIXME: handle OOM */
1676         section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1677
1678         alloc_size = sgen_nursery_size;
1679
1680         /* If there isn't enough space even for the nursery we should simply abort. */
1681         g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1682
1683 #ifdef SGEN_ALIGN_NURSERY
1684         data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1685 #else
1686         data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1687 #endif
1688         sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1689         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 ());
1690         section->data = section->next_data = data;
1691         section->size = alloc_size;
1692         section->end_data = data + sgen_nursery_size;
1693         scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1694         section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1695         section->num_scan_start = scan_starts;
1696
1697         nursery_section = section;
1698
1699         sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1700 }
1701
1702 void*
1703 mono_gc_get_nursery (int *shift_bits, size_t *size)
1704 {
1705         *size = sgen_nursery_size;
1706 #ifdef SGEN_ALIGN_NURSERY
1707         *shift_bits = DEFAULT_NURSERY_BITS;
1708 #else
1709         *shift_bits = -1;
1710 #endif
1711         return sgen_get_nursery_start ();
1712 }
1713
1714 void
1715 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1716 {
1717         SgenThreadInfo *info = mono_thread_info_current ();
1718
1719         /* Could be called from sgen_thread_unregister () with a NULL info */
1720         if (domain) {
1721                 g_assert (info);
1722                 info->stopped_domain = domain;
1723         }
1724 }
1725
1726 gboolean
1727 mono_gc_precise_stack_mark_enabled (void)
1728 {
1729         return !conservative_stack_mark;
1730 }
1731
1732 FILE *
1733 mono_gc_get_logfile (void)
1734 {
1735         return gc_debug_file;
1736 }
1737
1738 static void
1739 report_finalizer_roots_list (FinalizeReadyEntry *list)
1740 {
1741         GCRootReport report;
1742         FinalizeReadyEntry *fin;
1743
1744         report.count = 0;
1745         for (fin = list; fin; fin = fin->next) {
1746                 if (!fin->object)
1747                         continue;
1748                 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1749         }
1750         notify_gc_roots (&report);
1751 }
1752
1753 static void
1754 report_finalizer_roots (void)
1755 {
1756         report_finalizer_roots_list (fin_ready_list);
1757         report_finalizer_roots_list (critical_fin_list);
1758 }
1759
1760 static GCRootReport *root_report;
1761
1762 static void
1763 single_arg_report_root (void **obj)
1764 {
1765         if (*obj)
1766                 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1767 }
1768
1769 static void
1770 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1771 {
1772         switch (desc & ROOT_DESC_TYPE_MASK) {
1773         case ROOT_DESC_BITMAP:
1774                 desc >>= ROOT_DESC_TYPE_SHIFT;
1775                 while (desc) {
1776                         if ((desc & 1) && *start_root) {
1777                                 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1778                         }
1779                         desc >>= 1;
1780                         start_root++;
1781                 }
1782                 return;
1783         case ROOT_DESC_COMPLEX: {
1784                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1785                 int bwords = (*bitmap_data) - 1;
1786                 void **start_run = start_root;
1787                 bitmap_data++;
1788                 while (bwords-- > 0) {
1789                         gsize bmap = *bitmap_data++;
1790                         void **objptr = start_run;
1791                         while (bmap) {
1792                                 if ((bmap & 1) && *objptr) {
1793                                         add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1794                                 }
1795                                 bmap >>= 1;
1796                                 ++objptr;
1797                         }
1798                         start_run += GC_BITS_PER_WORD;
1799                 }
1800                 break;
1801         }
1802         case ROOT_DESC_USER: {
1803                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1804                 root_report = report;
1805                 marker (start_root, single_arg_report_root);
1806                 break;
1807         }
1808         case ROOT_DESC_RUN_LEN:
1809                 g_assert_not_reached ();
1810         default:
1811                 g_assert_not_reached ();
1812         }
1813 }
1814
1815 static void
1816 report_registered_roots_by_type (int root_type)
1817 {
1818         GCRootReport report;
1819         void **start_root;
1820         RootRecord *root;
1821         report.count = 0;
1822         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1823                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1824                 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1825         } SGEN_HASH_TABLE_FOREACH_END;
1826         notify_gc_roots (&report);
1827 }
1828
1829 static void
1830 report_registered_roots (void)
1831 {
1832         report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1833         report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1834 }
1835
1836 static void
1837 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1838 {
1839         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1840         SgenGrayQueue *queue = ctx.queue;
1841         FinalizeReadyEntry *fin;
1842
1843         for (fin = list; fin; fin = fin->next) {
1844                 if (!fin->object)
1845                         continue;
1846                 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1847                 copy_func (&fin->object, queue);
1848         }
1849 }
1850
1851 static const char*
1852 generation_name (int generation)
1853 {
1854         switch (generation) {
1855         case GENERATION_NURSERY: return "nursery";
1856         case GENERATION_OLD: return "old";
1857         default: g_assert_not_reached ();
1858         }
1859 }
1860
1861 const char*
1862 sgen_generation_name (int generation)
1863 {
1864         return generation_name (generation);
1865 }
1866
1867 SgenObjectOperations *
1868 sgen_get_current_object_ops (void){
1869         return &current_object_ops;
1870 }
1871
1872
1873 static void
1874 finish_gray_stack (int generation, GrayQueue *queue)
1875 {
1876         TV_DECLARE (atv);
1877         TV_DECLARE (btv);
1878         int done_with_ephemerons, ephemeron_rounds = 0;
1879         CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1880         ScanObjectFunc scan_func = current_object_ops.scan_object;
1881         ScanCopyContext ctx = { scan_func, copy_func, queue };
1882         char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1883         char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1884
1885         /*
1886          * We copied all the reachable objects. Now it's the time to copy
1887          * the objects that were not referenced by the roots, but by the copied objects.
1888          * we built a stack of objects pointed to by gray_start: they are
1889          * additional roots and we may add more items as we go.
1890          * We loop until gray_start == gray_objects which means no more objects have
1891          * been added. Note this is iterative: no recursion is involved.
1892          * We need to walk the LO list as well in search of marked big objects
1893          * (use a flag since this is needed only on major collections). We need to loop
1894          * here as well, so keep a counter of marked LO (increasing it in copy_object).
1895          *   To achieve better cache locality and cache usage, we drain the gray stack
1896          * frequently, after each object is copied, and just finish the work here.
1897          */
1898         sgen_drain_gray_stack (-1, ctx);
1899         TV_GETTIME (atv);
1900         SGEN_LOG (2, "%s generation done", generation_name (generation));
1901
1902         /*
1903         Reset bridge data, we might have lingering data from a previous collection if this is a major
1904         collection trigged by minor overflow.
1905
1906         We must reset the gathered bridges since their original block might be evacuated due to major
1907         fragmentation in the meanwhile and the bridge code should not have to deal with that.
1908         */
1909         sgen_bridge_reset_data ();
1910
1911         /*
1912          * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1913          * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1914          * objects that are in fact reachable.
1915          */
1916         done_with_ephemerons = 0;
1917         do {
1918                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1919                 sgen_drain_gray_stack (-1, ctx);
1920                 ++ephemeron_rounds;
1921         } while (!done_with_ephemerons);
1922
1923         sgen_scan_togglerefs (start_addr, end_addr, ctx);
1924         if (generation == GENERATION_OLD)
1925                 sgen_scan_togglerefs (sgen_get_nursery_start (), sgen_get_nursery_end (), ctx);
1926
1927         if (sgen_need_bridge_processing ()) {
1928                 sgen_collect_bridge_objects (generation, ctx);
1929                 if (generation == GENERATION_OLD)
1930                         sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1931         }
1932
1933         /*
1934         Make sure we drain the gray stack before processing disappearing links and finalizers.
1935         If we don't make sure it is empty we might wrongly see a live object as dead.
1936         */
1937         sgen_drain_gray_stack (-1, ctx);
1938
1939         /*
1940         We must clear weak links that don't track resurrection before processing object ready for
1941         finalization so they can be cleared before that.
1942         */
1943         sgen_null_link_in_range (generation, TRUE, ctx);
1944         if (generation == GENERATION_OLD)
1945                 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1946
1947
1948         /* walk the finalization queue and move also the objects that need to be
1949          * finalized: use the finalized objects as new roots so the objects they depend
1950          * on are also not reclaimed. As with the roots above, only objects in the nursery
1951          * are marked/copied.
1952          */
1953         sgen_finalize_in_range (generation, ctx);
1954         if (generation == GENERATION_OLD)
1955                 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1956         /* drain the new stack that might have been created */
1957         SGEN_LOG (6, "Precise scan of gray area post fin");
1958         sgen_drain_gray_stack (-1, ctx);
1959
1960         /*
1961          * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1962          */
1963         done_with_ephemerons = 0;
1964         do {
1965                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1966                 sgen_drain_gray_stack (-1, ctx);
1967                 ++ephemeron_rounds;
1968         } while (!done_with_ephemerons);
1969
1970         /*
1971          * Clear ephemeron pairs with unreachable keys.
1972          * We pass the copy func so we can figure out if an array was promoted or not.
1973          */
1974         clear_unreachable_ephemerons (ctx);
1975
1976         TV_GETTIME (btv);
1977         SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1978
1979         /*
1980          * handle disappearing links
1981          * Note we do this after checking the finalization queue because if an object
1982          * survives (at least long enough to be finalized) we don't clear the link.
1983          * This also deals with a possible issue with the monitor reclamation: with the Boehm
1984          * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1985          * called.
1986          */
1987         g_assert (sgen_gray_object_queue_is_empty (queue));
1988         for (;;) {
1989                 sgen_null_link_in_range (generation, FALSE, ctx);
1990                 if (generation == GENERATION_OLD)
1991                         sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1992                 if (sgen_gray_object_queue_is_empty (queue))
1993                         break;
1994                 sgen_drain_gray_stack (-1, ctx);
1995         }
1996
1997         g_assert (sgen_gray_object_queue_is_empty (queue));
1998 }
1999
2000 void
2001 sgen_check_section_scan_starts (GCMemSection *section)
2002 {
2003         int i;
2004         for (i = 0; i < section->num_scan_start; ++i) {
2005                 if (section->scan_starts [i]) {
2006                         guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2007                         g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2008                 }
2009         }
2010 }
2011
2012 static void
2013 check_scan_starts (void)
2014 {
2015         if (!do_scan_starts_check)
2016                 return;
2017         sgen_check_section_scan_starts (nursery_section);
2018         major_collector.check_scan_starts ();
2019 }
2020
2021 static void
2022 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
2023 {
2024         void **start_root;
2025         RootRecord *root;
2026         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2027                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
2028                 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
2029         } SGEN_HASH_TABLE_FOREACH_END;
2030 }
2031
2032 void
2033 sgen_dump_occupied (char *start, char *end, char *section_start)
2034 {
2035         fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2036 }
2037
2038 void
2039 sgen_dump_section (GCMemSection *section, const char *type)
2040 {
2041         char *start = section->data;
2042         char *end = section->data + section->size;
2043         char *occ_start = NULL;
2044         GCVTable *vt;
2045         char *old_start = NULL; /* just for debugging */
2046
2047         fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2048
2049         while (start < end) {
2050                 guint size;
2051                 MonoClass *class;
2052
2053                 if (!*(void**)start) {
2054                         if (occ_start) {
2055                                 sgen_dump_occupied (occ_start, start, section->data);
2056                                 occ_start = NULL;
2057                         }
2058                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2059                         continue;
2060                 }
2061                 g_assert (start < section->next_data);
2062
2063                 if (!occ_start)
2064                         occ_start = start;
2065
2066                 vt = (GCVTable*)LOAD_VTABLE (start);
2067                 class = vt->klass;
2068
2069                 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2070
2071                 /*
2072                 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2073                                 start - section->data,
2074                                 vt->klass->name_space, vt->klass->name,
2075                                 size);
2076                 */
2077
2078                 old_start = start;
2079                 start += size;
2080         }
2081         if (occ_start)
2082                 sgen_dump_occupied (occ_start, start, section->data);
2083
2084         fprintf (heap_dump_file, "</section>\n");
2085 }
2086
2087 static void
2088 dump_object (MonoObject *obj, gboolean dump_location)
2089 {
2090         static char class_name [1024];
2091
2092         MonoClass *class = mono_object_class (obj);
2093         int i, j;
2094
2095         /*
2096          * Python's XML parser is too stupid to parse angle brackets
2097          * in strings, so we just ignore them;
2098          */
2099         i = j = 0;
2100         while (class->name [i] && j < sizeof (class_name) - 1) {
2101                 if (!strchr ("<>\"", class->name [i]))
2102                         class_name [j++] = class->name [i];
2103                 ++i;
2104         }
2105         g_assert (j < sizeof (class_name));
2106         class_name [j] = 0;
2107
2108         fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2109                         class->name_space, class_name,
2110                         safe_object_get_size (obj));
2111         if (dump_location) {
2112                 const char *location;
2113                 if (ptr_in_nursery (obj))
2114                         location = "nursery";
2115                 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2116                         location = "major";
2117                 else
2118                         location = "LOS";
2119                 fprintf (heap_dump_file, " location=\"%s\"", location);
2120         }
2121         fprintf (heap_dump_file, "/>\n");
2122 }
2123
2124 static void
2125 dump_heap (const char *type, int num, const char *reason)
2126 {
2127         ObjectList *list;
2128         LOSObject *bigobj;
2129
2130         fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2131         if (reason)
2132                 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2133         fprintf (heap_dump_file, ">\n");
2134         fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2135         sgen_dump_internal_mem_usage (heap_dump_file);
2136         fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2137         /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2138         fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2139
2140         fprintf (heap_dump_file, "<pinned-objects>\n");
2141         for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2142                 dump_object (list->obj, TRUE);
2143         fprintf (heap_dump_file, "</pinned-objects>\n");
2144
2145         sgen_dump_section (nursery_section, "nursery");
2146
2147         major_collector.dump_heap (heap_dump_file);
2148
2149         fprintf (heap_dump_file, "<los>\n");
2150         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2151                 dump_object ((MonoObject*)bigobj->data, FALSE);
2152         fprintf (heap_dump_file, "</los>\n");
2153
2154         fprintf (heap_dump_file, "</collection>\n");
2155 }
2156
2157 void
2158 sgen_register_moved_object (void *obj, void *destination)
2159 {
2160         g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2161
2162         /* FIXME: handle this for parallel collector */
2163         g_assert (!sgen_collection_is_parallel ());
2164
2165         if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2166                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2167                 moved_objects_idx = 0;
2168         }
2169         moved_objects [moved_objects_idx++] = obj;
2170         moved_objects [moved_objects_idx++] = destination;
2171 }
2172
2173 static void
2174 init_stats (void)
2175 {
2176         static gboolean inited = FALSE;
2177
2178         if (inited)
2179                 return;
2180
2181         mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2182         mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2183         mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2184         mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2185         mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2186         mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2187         mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2188         mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2189
2190         mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2191         mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2192         mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2193         mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2194         mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2195         mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2196         mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2197         mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2198         mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2199         mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2200         mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2201         mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2202         mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2203
2204         mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2205
2206 #ifdef HEAVY_STATISTICS
2207         mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
2208         mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2209         mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2210         mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2211         mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2212         mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2213         mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2214         mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2215
2216         mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2217         mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2218
2219         mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2220         mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2221         mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2222         mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2223
2224         mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2225         mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2226
2227         mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2228
2229         mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2230         mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2231         mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2232         mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2233
2234         sgen_nursery_allocator_init_heavy_stats ();
2235         sgen_alloc_init_heavy_stats ();
2236 #endif
2237
2238         inited = TRUE;
2239 }
2240
2241
2242 static void
2243 reset_pinned_from_failed_allocation (void)
2244 {
2245         bytes_pinned_from_failed_allocation = 0;
2246 }
2247
2248 void
2249 sgen_set_pinned_from_failed_allocation (mword objsize)
2250 {
2251         bytes_pinned_from_failed_allocation += objsize;
2252 }
2253
2254 gboolean
2255 sgen_collection_is_parallel (void)
2256 {
2257         switch (current_collection_generation) {
2258         case GENERATION_NURSERY:
2259                 return nursery_collection_is_parallel;
2260         case GENERATION_OLD:
2261                 return major_collector.is_parallel;
2262         default:
2263                 g_error ("Invalid current generation %d", current_collection_generation);
2264         }
2265 }
2266
2267 gboolean
2268 sgen_collection_is_concurrent (void)
2269 {
2270         switch (current_collection_generation) {
2271         case GENERATION_NURSERY:
2272                 return FALSE;
2273         case GENERATION_OLD:
2274                 return concurrent_collection_in_progress;
2275         default:
2276                 g_error ("Invalid current generation %d", current_collection_generation);
2277         }
2278 }
2279
2280 gboolean
2281 sgen_concurrent_collection_in_progress (void)
2282 {
2283         return concurrent_collection_in_progress;
2284 }
2285
2286 typedef struct
2287 {
2288         char *heap_start;
2289         char *heap_end;
2290 } FinishRememberedSetScanJobData;
2291
2292 static void
2293 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2294 {
2295         FinishRememberedSetScanJobData *job_data = job_data_untyped;
2296
2297         remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2298         sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2299 }
2300
2301 typedef struct
2302 {
2303         CopyOrMarkObjectFunc copy_or_mark_func;
2304         ScanObjectFunc scan_func;
2305         char *heap_start;
2306         char *heap_end;
2307         int root_type;
2308 } ScanFromRegisteredRootsJobData;
2309
2310 static void
2311 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2312 {
2313         ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2314         ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2315                 sgen_workers_get_job_gray_queue (worker_data) };
2316
2317         scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2318         sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2319 }
2320
2321 typedef struct
2322 {
2323         char *heap_start;
2324         char *heap_end;
2325 } ScanThreadDataJobData;
2326
2327 static void
2328 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2329 {
2330         ScanThreadDataJobData *job_data = job_data_untyped;
2331
2332         scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2333                         sgen_workers_get_job_gray_queue (worker_data));
2334         sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2335 }
2336
2337 typedef struct
2338 {
2339         FinalizeReadyEntry *list;
2340 } ScanFinalizerEntriesJobData;
2341
2342 static void
2343 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2344 {
2345         ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2346         ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2347
2348         scan_finalizer_entries (job_data->list, ctx);
2349         sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2350 }
2351
2352 static void
2353 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2354 {
2355         g_assert (concurrent_collection_in_progress);
2356         major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2357 }
2358
2359 static void
2360 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2361 {
2362         g_assert (concurrent_collection_in_progress);
2363         sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2364 }
2365
2366 static void
2367 verify_scan_starts (char *start, char *end)
2368 {
2369         int i;
2370
2371         for (i = 0; i < nursery_section->num_scan_start; ++i) {
2372                 char *addr = nursery_section->scan_starts [i];
2373                 if (addr > start && addr < end)
2374                         SGEN_LOG (1, "NFC-BAD SCAN START [%d] %p for obj [%p %p]", i, addr, start, end);
2375         }
2376 }
2377
2378 static void
2379 verify_nursery (void)
2380 {
2381         char *start, *end, *cur, *hole_start;
2382
2383         if (!do_verify_nursery)
2384                 return;
2385
2386         /*This cleans up unused fragments */
2387         sgen_nursery_allocator_prepare_for_pinning ();
2388
2389         hole_start = start = cur = sgen_get_nursery_start ();
2390         end = sgen_get_nursery_end ();
2391
2392         while (cur < end) {
2393                 size_t ss, size;
2394
2395                 if (!*(void**)cur) {
2396                         cur += sizeof (void*);
2397                         continue;
2398                 }
2399
2400                 if (object_is_forwarded (cur))
2401                         SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2402                 else if (object_is_pinned (cur))
2403                         SGEN_LOG (1, "PINNED OBJ %p", cur);
2404
2405                 ss = safe_object_get_size ((MonoObject*)cur);
2406                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2407                 verify_scan_starts (cur, cur + size);
2408                 if (do_dump_nursery_content) {
2409                         if (cur > hole_start)
2410                                 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2411                         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 ());
2412                 }
2413                 cur += size;
2414                 hole_start = cur;
2415         }
2416 }
2417
2418 /*
2419  * Checks that no objects in the nursery are fowarded or pinned.  This
2420  * is a precondition to restarting the mutator while doing a
2421  * concurrent collection.  Note that we don't clear fragments because
2422  * we depend on that having happened earlier.
2423  */
2424 static void
2425 check_nursery_is_clean (void)
2426 {
2427         char *start, *end, *cur;
2428
2429         start = cur = sgen_get_nursery_start ();
2430         end = sgen_get_nursery_end ();
2431
2432         while (cur < end) {
2433                 size_t ss, size;
2434
2435                 if (!*(void**)cur) {
2436                         cur += sizeof (void*);
2437                         continue;
2438                 }
2439
2440                 g_assert (!object_is_forwarded (cur));
2441                 g_assert (!object_is_pinned (cur));
2442
2443                 ss = safe_object_get_size ((MonoObject*)cur);
2444                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2445                 verify_scan_starts (cur, cur + size);
2446
2447                 cur += size;
2448         }
2449 }
2450
2451 static void
2452 init_gray_queue (void)
2453 {
2454         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2455                 sgen_workers_init_distribute_gray_queue ();
2456                 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2457                                 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2458         } else {
2459                 sgen_gray_object_queue_init (&gray_queue, NULL);
2460         }
2461 }
2462
2463 static void
2464 pin_stage_object_callback (char *obj, size_t size, void *data)
2465 {
2466         sgen_pin_stage_ptr (obj);
2467         /* FIXME: do pin stats if enabled */
2468 }
2469
2470 /*
2471  * Collect objects in the nursery.  Returns whether to trigger a major
2472  * collection.
2473  */
2474 static gboolean
2475 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2476 {
2477         gboolean needs_major;
2478         size_t max_garbage_amount;
2479         char *nursery_next;
2480         FinishRememberedSetScanJobData *frssjd;
2481         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2482         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2483         ScanThreadDataJobData *stdjd;
2484         mword fragment_total;
2485         ScanCopyContext ctx;
2486         TV_DECLARE (all_atv);
2487         TV_DECLARE (all_btv);
2488         TV_DECLARE (atv);
2489         TV_DECLARE (btv);
2490
2491         if (disable_minor_collections)
2492                 return TRUE;
2493
2494         MONO_GC_BEGIN (GENERATION_NURSERY);
2495         binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2496
2497         verify_nursery ();
2498
2499 #ifndef DISABLE_PERFCOUNTERS
2500         mono_perfcounters->gc_collections0++;
2501 #endif
2502
2503         current_collection_generation = GENERATION_NURSERY;
2504         if (sgen_collection_is_parallel ())
2505                 current_object_ops = sgen_minor_collector.parallel_ops;
2506         else
2507                 current_object_ops = sgen_minor_collector.serial_ops;
2508
2509         reset_pinned_from_failed_allocation ();
2510
2511         check_scan_starts ();
2512
2513         sgen_nursery_alloc_prepare_for_minor ();
2514
2515         degraded_mode = 0;
2516         objects_pinned = 0;
2517         nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2518         /* FIXME: optimize later to use the higher address where an object can be present */
2519         nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2520
2521         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 ()));
2522         max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2523         g_assert (nursery_section->size >= max_garbage_amount);
2524
2525         /* world must be stopped already */
2526         TV_GETTIME (all_atv);
2527         atv = all_atv;
2528
2529         TV_GETTIME (btv);
2530         time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2531
2532         if (xdomain_checks) {
2533                 sgen_clear_nursery_fragments ();
2534                 check_for_xdomain_refs ();
2535         }
2536
2537         nursery_section->next_data = nursery_next;
2538
2539         major_collector.start_nursery_collection ();
2540
2541         sgen_memgov_minor_collection_start ();
2542
2543         init_gray_queue ();
2544
2545         stat_minor_gcs++;
2546         gc_stats.minor_gc_count ++;
2547
2548         MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2549
2550         sgen_process_fin_stage_entries ();
2551         sgen_process_dislink_stage_entries ();
2552
2553         MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2554
2555         /* pin from pinned handles */
2556         sgen_init_pinning ();
2557         mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2558         pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2559         /* pin cemented objects */
2560         sgen_cement_iterate (pin_stage_object_callback, NULL);
2561         /* identify pinned objects */
2562         sgen_optimize_pin_queue (0);
2563         sgen_pinning_setup_section (nursery_section);
2564         ctx.scan_func = NULL;
2565         ctx.copy_func = NULL;
2566         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2567         sgen_pin_objects_in_section (nursery_section, ctx);
2568         sgen_pinning_trim_queue_to_section (nursery_section);
2569
2570         TV_GETTIME (atv);
2571         time_minor_pinning += TV_ELAPSED (btv, atv);
2572         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2573         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2574
2575         MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2576
2577         if (whole_heap_check_before_collection) {
2578                 sgen_clear_nursery_fragments ();
2579                 sgen_check_whole_heap (finish_up_concurrent_mark);
2580         }
2581         if (consistency_check_at_minor_collection)
2582                 sgen_check_consistency ();
2583
2584         sgen_workers_start_all_workers ();
2585         sgen_workers_start_marking ();
2586
2587         frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2588         frssjd->heap_start = sgen_get_nursery_start ();
2589         frssjd->heap_end = nursery_next;
2590         sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2591
2592         /* we don't have complete write barrier yet, so we scan all the old generation sections */
2593         TV_GETTIME (btv);
2594         time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2595         SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2596
2597         MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2598
2599         if (!sgen_collection_is_parallel ()) {
2600                 ctx.scan_func = current_object_ops.scan_object;
2601                 ctx.copy_func = NULL;
2602                 ctx.queue = &gray_queue;
2603                 sgen_drain_gray_stack (-1, ctx);
2604         }
2605
2606         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2607                 report_registered_roots ();
2608         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2609                 report_finalizer_roots ();
2610         TV_GETTIME (atv);
2611         time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2612
2613         MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2614
2615         /* registered roots, this includes static fields */
2616         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2617         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2618         scrrjd_normal->scan_func = current_object_ops.scan_object;
2619         scrrjd_normal->heap_start = sgen_get_nursery_start ();
2620         scrrjd_normal->heap_end = nursery_next;
2621         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2622         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2623
2624         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2625         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2626         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2627         scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2628         scrrjd_wbarrier->heap_end = nursery_next;
2629         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2630         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2631
2632         TV_GETTIME (btv);
2633         time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2634
2635         MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2636
2637         /* thread data */
2638         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2639         stdjd->heap_start = sgen_get_nursery_start ();
2640         stdjd->heap_end = nursery_next;
2641         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2642
2643         TV_GETTIME (atv);
2644         time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2645         btv = atv;
2646
2647         MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2648
2649         g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2650
2651         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2652                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2653
2654         /* Scan the list of objects ready for finalization. If */
2655         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2656         sfejd_fin_ready->list = fin_ready_list;
2657         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2658
2659         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2660         sfejd_critical_fin->list = critical_fin_list;
2661         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2662
2663         MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2664
2665         finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2666         TV_GETTIME (atv);
2667         time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2668         mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2669
2670         MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2671
2672         /*
2673          * The (single-threaded) finalization code might have done
2674          * some copying/marking so we can only reset the GC thread's
2675          * worker data here instead of earlier when we joined the
2676          * workers.
2677          */
2678         sgen_workers_reset_data ();
2679
2680         if (objects_pinned) {
2681                 sgen_optimize_pin_queue (0);
2682                 sgen_pinning_setup_section (nursery_section);
2683         }
2684
2685         /* walk the pin_queue, build up the fragment list of free memory, unmark
2686          * pinned objects as we go, memzero() the empty fragments so they are ready for the
2687          * next allocations.
2688          */
2689         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2690         fragment_total = sgen_build_nursery_fragments (nursery_section,
2691                         nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2692                         unpin_queue);
2693         if (!fragment_total)
2694                 degraded_mode = 1;
2695
2696         /* Clear TLABs for all threads */
2697         sgen_clear_tlabs ();
2698
2699         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2700         TV_GETTIME (btv);
2701         time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2702         SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2703
2704         if (consistency_check_at_minor_collection)
2705                 sgen_check_major_refs ();
2706
2707         major_collector.finish_nursery_collection ();
2708
2709         TV_GETTIME (all_btv);
2710         gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2711
2712         if (heap_dump_file)
2713                 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2714
2715         /* prepare the pin queue for the next collection */
2716         sgen_finish_pinning ();
2717         if (fin_ready_list || critical_fin_list) {
2718                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2719                 mono_gc_finalize_notify ();
2720         }
2721         sgen_pin_stats_reset ();
2722         /* clear cemented hash */
2723         sgen_cement_clear_below_threshold ();
2724
2725         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2726
2727         remset.finish_minor_collection ();
2728
2729         check_scan_starts ();
2730
2731         binary_protocol_flush_buffers (FALSE);
2732
2733         sgen_memgov_minor_collection_end ();
2734
2735         /*objects are late pinned because of lack of memory, so a major is a good call*/
2736         needs_major = objects_pinned > 0;
2737         current_collection_generation = -1;
2738         objects_pinned = 0;
2739
2740         MONO_GC_END (GENERATION_NURSERY);
2741         binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2742
2743         if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2744                 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2745
2746         return needs_major;
2747 }
2748
2749 static void
2750 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2751 {
2752         ctx->scan_func (obj, ctx->queue);
2753 }
2754
2755 static void
2756 scan_nursery_objects (ScanCopyContext ctx)
2757 {
2758         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2759                         (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2760 }
2761
2762 static void
2763 major_copy_or_mark_from_roots (int *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2764 {
2765         LOSObject *bigobj;
2766         TV_DECLARE (atv);
2767         TV_DECLARE (btv);
2768         /* FIXME: only use these values for the precise scan
2769          * note that to_space pointers should be excluded anyway...
2770          */
2771         char *heap_start = NULL;
2772         char *heap_end = (char*)-1;
2773         gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2774         GCRootReport root_report = { 0 };
2775         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2776         ScanThreadDataJobData *stdjd;
2777         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2778         ScanCopyContext ctx;
2779
2780         if (concurrent_collection_in_progress) {
2781                 /*This cleans up unused fragments */
2782                 sgen_nursery_allocator_prepare_for_pinning ();
2783
2784                 if (do_concurrent_checks)
2785                         check_nursery_is_clean ();
2786         } else {
2787                 /* The concurrent collector doesn't touch the nursery. */
2788                 sgen_nursery_alloc_prepare_for_major ();
2789         }
2790
2791         init_gray_queue ();
2792
2793         TV_GETTIME (atv);
2794
2795         /* Pinning depends on this */
2796         sgen_clear_nursery_fragments ();
2797
2798         if (whole_heap_check_before_collection)
2799                 sgen_check_whole_heap (finish_up_concurrent_mark);
2800
2801         TV_GETTIME (btv);
2802         time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2803
2804         if (!sgen_collection_is_concurrent ())
2805                 nursery_section->next_data = sgen_get_nursery_end ();
2806         /* we should also coalesce scanning from sections close to each other
2807          * and deal with pointers outside of the sections later.
2808          */
2809
2810         objects_pinned = 0;
2811         *major_collector.have_swept = FALSE;
2812
2813         if (xdomain_checks) {
2814                 sgen_clear_nursery_fragments ();
2815                 check_for_xdomain_refs ();
2816         }
2817
2818         if (!concurrent_collection_in_progress) {
2819                 /* Remsets are not useful for a major collection */
2820                 remset.prepare_for_major_collection ();
2821         }
2822
2823         sgen_process_fin_stage_entries ();
2824         sgen_process_dislink_stage_entries ();
2825
2826         TV_GETTIME (atv);
2827         sgen_init_pinning ();
2828         SGEN_LOG (6, "Collecting pinned addresses");
2829         pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2830
2831         if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2832                 if (major_collector.is_concurrent) {
2833                         /*
2834                          * The concurrent major collector cannot evict
2835                          * yet, so we need to pin cemented objects to
2836                          * not break some asserts.
2837                          *
2838                          * FIXME: We could evict now!
2839                          */
2840                         sgen_cement_iterate (pin_stage_object_callback, NULL);
2841                 }
2842
2843                 if (!concurrent_collection_in_progress)
2844                         sgen_cement_reset ();
2845         }
2846
2847         sgen_optimize_pin_queue (0);
2848
2849         /*
2850          * The concurrent collector doesn't move objects, neither on
2851          * the major heap nor in the nursery, so we can mark even
2852          * before pinning has finished.  For the non-concurrent
2853          * collector we start the workers after pinning.
2854          */
2855         if (concurrent_collection_in_progress) {
2856                 sgen_workers_start_all_workers ();
2857                 sgen_workers_start_marking ();
2858         }
2859
2860         /*
2861          * pin_queue now contains all candidate pointers, sorted and
2862          * uniqued.  We must do two passes now to figure out which
2863          * objects are pinned.
2864          *
2865          * The first is to find within the pin_queue the area for each
2866          * section.  This requires that the pin_queue be sorted.  We
2867          * also process the LOS objects and pinned chunks here.
2868          *
2869          * The second, destructive, pass is to reduce the section
2870          * areas to pointers to the actually pinned objects.
2871          */
2872         SGEN_LOG (6, "Pinning from sections");
2873         /* first pass for the sections */
2874         sgen_find_section_pin_queue_start_end (nursery_section);
2875         major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2876         /* identify possible pointers to the insize of large objects */
2877         SGEN_LOG (6, "Pinning from large objects");
2878         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2879                 int dummy;
2880                 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2881                         binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2882
2883 #ifdef ENABLE_DTRACE
2884                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2885                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2886                                 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2887                         }
2888 #endif
2889
2890                         if (sgen_los_object_is_pinned (bigobj->data)) {
2891                                 g_assert (finish_up_concurrent_mark);
2892                                 continue;
2893                         }
2894                         sgen_los_pin_object (bigobj->data);
2895                         /* FIXME: only enqueue if object has references */
2896                         GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2897                         if (G_UNLIKELY (do_pin_stats))
2898                                 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2899                         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));
2900
2901                         if (profile_roots)
2902                                 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2903                 }
2904         }
2905         if (profile_roots)
2906                 notify_gc_roots (&root_report);
2907         /* second pass for the sections */
2908         ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2909         ctx.copy_func = NULL;
2910         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2911
2912         /*
2913          * Concurrent mark never follows references into the nursery.
2914          * In the start and finish pauses we must scan live nursery
2915          * objects, though.  We could simply scan all nursery objects,
2916          * but that would be conservative.  The easiest way is to do a
2917          * nursery collection, which copies all live nursery objects
2918          * (except pinned ones, with the simple nursery) to the major
2919          * heap.  Scanning the mod union table later will then scan
2920          * those promoted objects, provided they're reachable.  Pinned
2921          * objects in the nursery - which we can trivially find in the
2922          * pinning queue - are treated as roots in the mark pauses.
2923          *
2924          * The split nursery complicates the latter part because
2925          * non-pinned objects can survive in the nursery.  That's why
2926          * we need to do a full front-to-back scan of the nursery,
2927          * marking all objects.
2928          *
2929          * Non-concurrent mark evacuates from the nursery, so it's
2930          * sufficient to just scan pinned nursery objects.
2931          */
2932         if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2933                 scan_nursery_objects (ctx);
2934         } else {
2935                 sgen_pin_objects_in_section (nursery_section, ctx);
2936                 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2937                         sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2938         }
2939
2940         major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2941         if (old_next_pin_slot)
2942                 *old_next_pin_slot = sgen_get_pinned_count ();
2943
2944         TV_GETTIME (btv);
2945         time_major_pinning += TV_ELAPSED (atv, btv);
2946         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2947         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2948
2949         major_collector.init_to_space ();
2950
2951 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2952         main_gc_thread = mono_native_thread_self ();
2953 #endif
2954
2955         if (!concurrent_collection_in_progress && major_collector.is_parallel) {
2956                 sgen_workers_start_all_workers ();
2957                 sgen_workers_start_marking ();
2958         }
2959
2960         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2961                 report_registered_roots ();
2962         TV_GETTIME (atv);
2963         time_major_scan_pinned += TV_ELAPSED (btv, atv);
2964
2965         /* registered roots, this includes static fields */
2966         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2967         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2968         scrrjd_normal->scan_func = current_object_ops.scan_object;
2969         scrrjd_normal->heap_start = heap_start;
2970         scrrjd_normal->heap_end = heap_end;
2971         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2972         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2973
2974         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2975         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2976         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2977         scrrjd_wbarrier->heap_start = heap_start;
2978         scrrjd_wbarrier->heap_end = heap_end;
2979         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2980         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2981
2982         TV_GETTIME (btv);
2983         time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2984
2985         /* Threads */
2986         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2987         stdjd->heap_start = heap_start;
2988         stdjd->heap_end = heap_end;
2989         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2990
2991         TV_GETTIME (atv);
2992         time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2993
2994         TV_GETTIME (btv);
2995         time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2996
2997         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2998                 report_finalizer_roots ();
2999
3000         /* scan the list of objects ready for finalization */
3001         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3002         sfejd_fin_ready->list = fin_ready_list;
3003         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
3004
3005         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3006         sfejd_critical_fin->list = critical_fin_list;
3007         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
3008
3009         if (scan_mod_union) {
3010                 g_assert (finish_up_concurrent_mark);
3011
3012                 /* Mod union card table */
3013                 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
3014                 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
3015         }
3016
3017         TV_GETTIME (atv);
3018         time_major_scan_finalized += TV_ELAPSED (btv, atv);
3019         SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
3020
3021         TV_GETTIME (btv);
3022         time_major_scan_big_objects += TV_ELAPSED (atv, btv);
3023
3024         if (concurrent_collection_in_progress) {
3025                 /* prepare the pin queue for the next collection */
3026                 sgen_finish_pinning ();
3027
3028                 sgen_pin_stats_reset ();
3029
3030                 if (do_concurrent_checks)
3031                         check_nursery_is_clean ();
3032         }
3033 }
3034
3035 static void
3036 major_start_collection (gboolean concurrent, int *old_next_pin_slot)
3037 {
3038         MONO_GC_BEGIN (GENERATION_OLD);
3039         binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
3040
3041         current_collection_generation = GENERATION_OLD;
3042 #ifndef DISABLE_PERFCOUNTERS
3043         mono_perfcounters->gc_collections1++;
3044 #endif
3045
3046         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3047
3048         if (concurrent) {
3049                 g_assert (major_collector.is_concurrent);
3050                 concurrent_collection_in_progress = TRUE;
3051
3052                 sgen_cement_concurrent_start ();
3053
3054                 current_object_ops = major_collector.major_concurrent_ops;
3055         } else {
3056                 current_object_ops = major_collector.major_ops;
3057         }
3058
3059         reset_pinned_from_failed_allocation ();
3060
3061         sgen_memgov_major_collection_start ();
3062
3063         //count_ref_nonref_objs ();
3064         //consistency_check ();
3065
3066         check_scan_starts ();
3067
3068         degraded_mode = 0;
3069         SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
3070         stat_major_gcs++;
3071         gc_stats.major_gc_count ++;
3072
3073         if (major_collector.start_major_collection)
3074                 major_collector.start_major_collection ();
3075
3076         major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
3077 }
3078
3079 static void
3080 wait_for_workers_to_finish (void)
3081 {
3082         if (concurrent_collection_in_progress || major_collector.is_parallel) {
3083                 gray_queue_redirect (&gray_queue);
3084                 sgen_workers_join ();
3085         }
3086
3087         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3088
3089 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3090         main_gc_thread = NULL;
3091 #endif
3092 }
3093
3094 static void
3095 major_finish_collection (const char *reason, int old_next_pin_slot, gboolean scan_mod_union)
3096 {
3097         LOSObject *bigobj, *prevbo;
3098         TV_DECLARE (atv);
3099         TV_DECLARE (btv);
3100
3101         TV_GETTIME (btv);
3102
3103         if (concurrent_collection_in_progress || major_collector.is_parallel)
3104                 wait_for_workers_to_finish ();
3105
3106         if (concurrent_collection_in_progress) {
3107                 current_object_ops = major_collector.major_concurrent_ops;
3108
3109                 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
3110                 wait_for_workers_to_finish ();
3111
3112                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3113
3114                 if (do_concurrent_checks)
3115                         check_nursery_is_clean ();
3116         } else {
3117                 current_object_ops = major_collector.major_ops;
3118         }
3119
3120         /*
3121          * The workers have stopped so we need to finish gray queue
3122          * work that might result from finalization in the main GC
3123          * thread.  Redirection must therefore be turned off.
3124          */
3125         sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
3126         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3127
3128         /* all the objects in the heap */
3129         finish_gray_stack (GENERATION_OLD, &gray_queue);
3130         TV_GETTIME (atv);
3131         time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3132
3133         /*
3134          * The (single-threaded) finalization code might have done
3135          * some copying/marking so we can only reset the GC thread's
3136          * worker data here instead of earlier when we joined the
3137          * workers.
3138          */
3139         sgen_workers_reset_data ();
3140
3141         if (objects_pinned) {
3142                 g_assert (!concurrent_collection_in_progress);
3143
3144                 /*This is slow, but we just OOM'd*/
3145                 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3146                 sgen_optimize_pin_queue (0);
3147                 sgen_find_section_pin_queue_start_end (nursery_section);
3148                 objects_pinned = 0;
3149         }
3150
3151         reset_heap_boundaries ();
3152         sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3153
3154         if (check_mark_bits_after_major_collection)
3155                 sgen_check_major_heap_marked ();
3156
3157         MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
3158
3159         /* sweep the big objects list */
3160         prevbo = NULL;
3161         for (bigobj = los_object_list; bigobj;) {
3162                 g_assert (!object_is_pinned (bigobj->data));
3163                 if (sgen_los_object_is_pinned (bigobj->data)) {
3164                         sgen_los_unpin_object (bigobj->data);
3165                         sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
3166                 } else {
3167                         LOSObject *to_free;
3168                         /* not referenced anywhere, so we can free it */
3169                         if (prevbo)
3170                                 prevbo->next = bigobj->next;
3171                         else
3172                                 los_object_list = bigobj->next;
3173                         to_free = bigobj;
3174                         bigobj = bigobj->next;
3175                         sgen_los_free_object (to_free);
3176                         continue;
3177                 }
3178                 prevbo = bigobj;
3179                 bigobj = bigobj->next;
3180         }
3181
3182         TV_GETTIME (btv);
3183         time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3184
3185         sgen_los_sweep ();
3186
3187         TV_GETTIME (atv);
3188         time_major_los_sweep += TV_ELAPSED (btv, atv);
3189
3190         major_collector.sweep ();
3191
3192         MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
3193
3194         TV_GETTIME (btv);
3195         time_major_sweep += TV_ELAPSED (atv, btv);
3196
3197         if (!concurrent_collection_in_progress) {
3198                 /* walk the pin_queue, build up the fragment list of free memory, unmark
3199                  * pinned objects as we go, memzero() the empty fragments so they are ready for the
3200                  * next allocations.
3201                  */
3202                 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
3203                         degraded_mode = 1;
3204
3205                 /* prepare the pin queue for the next collection */
3206                 sgen_finish_pinning ();
3207
3208                 /* Clear TLABs for all threads */
3209                 sgen_clear_tlabs ();
3210
3211                 sgen_pin_stats_reset ();
3212         }
3213
3214         if (concurrent_collection_in_progress)
3215                 sgen_cement_concurrent_finish ();
3216         sgen_cement_clear_below_threshold ();
3217
3218         TV_GETTIME (atv);
3219         time_major_fragment_creation += TV_ELAPSED (btv, atv);
3220
3221         if (heap_dump_file)
3222                 dump_heap ("major", stat_major_gcs - 1, reason);
3223
3224         if (fin_ready_list || critical_fin_list) {
3225                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
3226                 mono_gc_finalize_notify ();
3227         }
3228
3229         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3230
3231         sgen_memgov_major_collection_end ();
3232         current_collection_generation = -1;
3233
3234         major_collector.finish_major_collection ();
3235
3236         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3237
3238         if (concurrent_collection_in_progress)
3239                 concurrent_collection_in_progress = FALSE;
3240
3241         check_scan_starts ();
3242
3243         binary_protocol_flush_buffers (FALSE);
3244
3245         //consistency_check ();
3246
3247         MONO_GC_END (GENERATION_OLD);
3248         binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
3249 }
3250
3251 static gboolean
3252 major_do_collection (const char *reason)
3253 {
3254         TV_DECLARE (all_atv);
3255         TV_DECLARE (all_btv);
3256         int old_next_pin_slot;
3257
3258         if (major_collector.get_and_reset_num_major_objects_marked) {
3259                 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3260                 g_assert (!num_marked);
3261         }
3262
3263         /* world must be stopped already */
3264         TV_GETTIME (all_atv);
3265
3266         major_start_collection (FALSE, &old_next_pin_slot);
3267         major_finish_collection (reason, old_next_pin_slot, FALSE);
3268
3269         TV_GETTIME (all_btv);
3270         gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3271
3272         /* FIXME: also report this to the user, preferably in gc-end. */
3273         if (major_collector.get_and_reset_num_major_objects_marked)
3274                 major_collector.get_and_reset_num_major_objects_marked ();
3275
3276         return bytes_pinned_from_failed_allocation > 0;
3277 }
3278
3279 static gboolean major_do_collection (const char *reason);
3280
3281 static void
3282 major_start_concurrent_collection (const char *reason)
3283 {
3284         long long num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3285
3286         g_assert (num_objects_marked == 0);
3287
3288         MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3289
3290         // FIXME: store reason and pass it when finishing
3291         major_start_collection (TRUE, NULL);
3292
3293         gray_queue_redirect (&gray_queue);
3294         sgen_workers_wait_for_jobs ();
3295
3296         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3297         MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3298
3299         current_collection_generation = -1;
3300 }
3301
3302 static gboolean
3303 major_update_or_finish_concurrent_collection (gboolean force_finish)
3304 {
3305         SgenGrayQueue unpin_queue;
3306         memset (&unpin_queue, 0, sizeof (unpin_queue));
3307
3308         MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3309
3310         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3311
3312         major_collector.update_cardtable_mod_union ();
3313         sgen_los_update_cardtable_mod_union ();
3314
3315         if (!force_finish && !sgen_workers_all_done ()) {
3316                 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3317                 return FALSE;
3318         }
3319
3320         collect_nursery (&unpin_queue, TRUE);
3321
3322         current_collection_generation = GENERATION_OLD;
3323         major_finish_collection ("finishing", -1, TRUE);
3324
3325         if (whole_heap_check_before_collection)
3326                 sgen_check_whole_heap (FALSE);
3327
3328         unpin_objects_from_queue (&unpin_queue);
3329         sgen_gray_object_queue_deinit (&unpin_queue);
3330
3331         MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3332
3333         current_collection_generation = -1;
3334
3335         return TRUE;
3336 }
3337
3338 /*
3339  * Ensure an allocation request for @size will succeed by freeing enough memory.
3340  *
3341  * LOCKING: The GC lock MUST be held.
3342  */
3343 void
3344 sgen_ensure_free_space (size_t size)
3345 {
3346         int generation_to_collect = -1;
3347         const char *reason = NULL;
3348
3349
3350         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3351                 if (sgen_need_major_collection (size)) {
3352                         reason = "LOS overflow";
3353                         generation_to_collect = GENERATION_OLD;
3354                 }
3355         } else {
3356                 if (degraded_mode) {
3357                         if (sgen_need_major_collection (size)) {
3358                                 reason = "Degraded mode overflow";
3359                                 generation_to_collect = GENERATION_OLD;
3360                         }
3361                 } else if (sgen_need_major_collection (size)) {
3362                         reason = "Minor allowance";
3363                         generation_to_collect = GENERATION_OLD;
3364                 } else {
3365                         generation_to_collect = GENERATION_NURSERY;
3366                         reason = "Nursery full";
3367                 }
3368         }
3369
3370         if (generation_to_collect == -1) {
3371                 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3372                         generation_to_collect = GENERATION_OLD;
3373                         reason = "Finish concurrent collection";
3374                 }
3375         }
3376
3377         if (generation_to_collect == -1)
3378                 return;
3379         sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3380 }
3381
3382 void
3383 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3384 {
3385         TV_DECLARE (gc_end);
3386         GGTimingInfo infos [2];
3387         int overflow_generation_to_collect = -1;
3388         int oldest_generation_collected = generation_to_collect;
3389         const char *overflow_reason = NULL;
3390
3391         MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3392
3393         g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3394
3395         memset (infos, 0, sizeof (infos));
3396         mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3397
3398         infos [0].generation = generation_to_collect;
3399         infos [0].reason = reason;
3400         infos [0].is_overflow = FALSE;
3401         TV_GETTIME (infos [0].total_time);
3402         infos [1].generation = -1;
3403
3404         sgen_stop_world (generation_to_collect);
3405
3406         if (concurrent_collection_in_progress) {
3407                 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3408                         oldest_generation_collected = GENERATION_OLD;
3409                         goto done;
3410                 }
3411                 if (generation_to_collect == GENERATION_OLD)
3412                         goto done;
3413         } else {
3414                 if (generation_to_collect == GENERATION_OLD &&
3415                                 allow_synchronous_major &&
3416                                 major_collector.want_synchronous_collection &&
3417                                 *major_collector.want_synchronous_collection) {
3418                         wait_to_finish = TRUE;
3419                 }
3420         }
3421
3422         //FIXME extract overflow reason
3423         if (generation_to_collect == GENERATION_NURSERY) {
3424                 if (collect_nursery (NULL, FALSE)) {
3425                         overflow_generation_to_collect = GENERATION_OLD;
3426                         overflow_reason = "Minor overflow";
3427                 }
3428         } else {
3429                 if (major_collector.is_concurrent) {
3430                         g_assert (!concurrent_collection_in_progress);
3431                         if (!wait_to_finish)
3432                                 collect_nursery (NULL, FALSE);
3433                 }
3434
3435                 if (major_collector.is_concurrent && !wait_to_finish) {
3436                         major_start_concurrent_collection (reason);
3437                         // FIXME: set infos[0] properly
3438                         goto done;
3439                 } else {
3440                         if (major_do_collection (reason)) {
3441                                 overflow_generation_to_collect = GENERATION_NURSERY;
3442                                 overflow_reason = "Excessive pinning";
3443                         }
3444                 }
3445         }
3446
3447         TV_GETTIME (gc_end);
3448         infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3449
3450
3451         if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3452                 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3453                 infos [1].generation = overflow_generation_to_collect;
3454                 infos [1].reason = overflow_reason;
3455                 infos [1].is_overflow = TRUE;
3456                 infos [1].total_time = gc_end;
3457
3458                 if (overflow_generation_to_collect == GENERATION_NURSERY)
3459                         collect_nursery (NULL, FALSE);
3460                 else
3461                         major_do_collection (overflow_reason);
3462
3463                 TV_GETTIME (gc_end);
3464                 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3465
3466                 /* keep events symmetric */
3467                 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3468
3469                 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3470         }
3471
3472         SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3473
3474         /* this also sets the proper pointers for the next allocation */
3475         if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3476                 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3477                 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3478                 sgen_dump_pin_queue ();
3479                 degraded_mode = 1;
3480         }
3481
3482  done:
3483         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3484
3485         sgen_restart_world (oldest_generation_collected, infos);
3486
3487         mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3488 }
3489
3490 /*
3491  * ######################################################################
3492  * ########  Memory allocation from the OS
3493  * ######################################################################
3494  * This section of code deals with getting memory from the OS and
3495  * allocating memory for GC-internal data structures.
3496  * Internal memory can be handled with a freelist for small objects.
3497  */
3498
3499 /*
3500  * Debug reporting.
3501  */
3502 G_GNUC_UNUSED static void
3503 report_internal_mem_usage (void)
3504 {
3505         printf ("Internal memory usage:\n");
3506         sgen_report_internal_mem_usage ();
3507         printf ("Pinned memory usage:\n");
3508         major_collector.report_pinned_memory_usage ();
3509 }
3510
3511 /*
3512  * ######################################################################
3513  * ########  Finalization support
3514  * ######################################################################
3515  */
3516
3517 static inline gboolean
3518 sgen_major_is_object_alive (void *object)
3519 {
3520         mword objsize;
3521
3522         /* Oldgen objects can be pinned and forwarded too */
3523         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3524                 return TRUE;
3525
3526         /*
3527          * FIXME: major_collector.is_object_live() also calculates the
3528          * size.  Avoid the double calculation.
3529          */
3530         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3531         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3532                 return sgen_los_object_is_pinned (object);
3533
3534         return major_collector.is_object_live (object);
3535 }
3536
3537 /*
3538  * If the object has been forwarded it means it's still referenced from a root.
3539  * If it is pinned it's still alive as well.
3540  * A LOS object is only alive if we have pinned it.
3541  * Return TRUE if @obj is ready to be finalized.
3542  */
3543 static inline gboolean
3544 sgen_is_object_alive (void *object)
3545 {
3546         if (ptr_in_nursery (object))
3547                 return sgen_nursery_is_object_alive (object);
3548
3549         return sgen_major_is_object_alive (object);
3550 }
3551
3552 /*
3553  * This function returns true if @object is either alive or it belongs to the old gen
3554  * and we're currently doing a minor collection.
3555  */
3556 static inline int
3557 sgen_is_object_alive_for_current_gen (char *object)
3558 {
3559         if (ptr_in_nursery (object))
3560                 return sgen_nursery_is_object_alive (object);
3561
3562         if (current_collection_generation == GENERATION_NURSERY)
3563                 return TRUE;
3564
3565         return sgen_major_is_object_alive (object);
3566 }
3567
3568 /*
3569  * This function returns true if @object is either alive and belongs to the
3570  * current collection - major collections are full heap, so old gen objects
3571  * are never alive during a minor collection.
3572  */
3573 static inline int
3574 sgen_is_object_alive_and_on_current_collection (char *object)
3575 {
3576         if (ptr_in_nursery (object))
3577                 return sgen_nursery_is_object_alive (object);
3578
3579         if (current_collection_generation == GENERATION_NURSERY)
3580                 return FALSE;
3581
3582         return sgen_major_is_object_alive (object);
3583 }
3584
3585
3586 gboolean
3587 sgen_gc_is_object_ready_for_finalization (void *object)
3588 {
3589         return !sgen_is_object_alive (object);
3590 }
3591
3592 static gboolean
3593 has_critical_finalizer (MonoObject *obj)
3594 {
3595         MonoClass *class;
3596
3597         if (!mono_defaults.critical_finalizer_object)
3598                 return FALSE;
3599
3600         class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3601
3602         return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3603 }
3604
3605 void
3606 sgen_queue_finalization_entry (MonoObject *obj)
3607 {
3608         FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3609         gboolean critical = has_critical_finalizer (obj);
3610         entry->object = obj;
3611         if (critical) {
3612                 entry->next = critical_fin_list;
3613                 critical_fin_list = entry;
3614         } else {
3615                 entry->next = fin_ready_list;
3616                 fin_ready_list = entry;
3617         }
3618
3619 #ifdef ENABLE_DTRACE
3620         if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3621                 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3622                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3623                 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3624                                 vt->klass->name_space, vt->klass->name, gen, critical);
3625         }
3626 #endif
3627 }
3628
3629 gboolean
3630 sgen_object_is_live (void *obj)
3631 {
3632         return sgen_is_object_alive_and_on_current_collection (obj);
3633 }
3634
3635 /* LOCKING: requires that the GC lock is held */
3636 static void
3637 null_ephemerons_for_domain (MonoDomain *domain)
3638 {
3639         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3640
3641         while (current) {
3642                 MonoObject *object = (MonoObject*)current->array;
3643
3644                 if (object && !object->vtable) {
3645                         EphemeronLinkNode *tmp = current;
3646
3647                         if (prev)
3648                                 prev->next = current->next;
3649                         else
3650                                 ephemeron_list = current->next;
3651
3652                         current = current->next;
3653                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3654                 } else {
3655                         prev = current;
3656                         current = current->next;
3657                 }
3658         }
3659 }
3660
3661 /* LOCKING: requires that the GC lock is held */
3662 static void
3663 clear_unreachable_ephemerons (ScanCopyContext ctx)
3664 {
3665         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3666         GrayQueue *queue = ctx.queue;
3667         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3668         MonoArray *array;
3669         Ephemeron *cur, *array_end;
3670         char *tombstone;
3671
3672         while (current) {
3673                 char *object = current->array;
3674
3675                 if (!sgen_is_object_alive_for_current_gen (object)) {
3676                         EphemeronLinkNode *tmp = current;
3677
3678                         SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3679
3680                         if (prev)
3681                                 prev->next = current->next;
3682                         else
3683                                 ephemeron_list = current->next;
3684
3685                         current = current->next;
3686                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3687
3688                         continue;
3689                 }
3690
3691                 copy_func ((void**)&object, queue);
3692                 current->array = object;
3693
3694                 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3695
3696                 array = (MonoArray*)object;
3697                 cur = mono_array_addr (array, Ephemeron, 0);
3698                 array_end = cur + mono_array_length_fast (array);
3699                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3700
3701                 for (; cur < array_end; ++cur) {
3702                         char *key = (char*)cur->key;
3703
3704                         if (!key || key == tombstone)
3705                                 continue;
3706
3707                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3708                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3709                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3710
3711                         if (!sgen_is_object_alive_for_current_gen (key)) {
3712                                 cur->key = tombstone;
3713                                 cur->value = NULL;
3714                                 continue;
3715                         }
3716                 }
3717                 prev = current;
3718                 current = current->next;
3719         }
3720 }
3721
3722 /*
3723 LOCKING: requires that the GC lock is held
3724
3725 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3726 */
3727 static int
3728 mark_ephemerons_in_range (ScanCopyContext ctx)
3729 {
3730         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3731         GrayQueue *queue = ctx.queue;
3732         int nothing_marked = 1;
3733         EphemeronLinkNode *current = ephemeron_list;
3734         MonoArray *array;
3735         Ephemeron *cur, *array_end;
3736         char *tombstone;
3737
3738         for (current = ephemeron_list; current; current = current->next) {
3739                 char *object = current->array;
3740                 SGEN_LOG (5, "Ephemeron array at %p", object);
3741
3742                 /*It has to be alive*/
3743                 if (!sgen_is_object_alive_for_current_gen (object)) {
3744                         SGEN_LOG (5, "\tnot reachable");
3745                         continue;
3746                 }
3747
3748                 copy_func ((void**)&object, queue);
3749
3750                 array = (MonoArray*)object;
3751                 cur = mono_array_addr (array, Ephemeron, 0);
3752                 array_end = cur + mono_array_length_fast (array);
3753                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3754
3755                 for (; cur < array_end; ++cur) {
3756                         char *key = cur->key;
3757
3758                         if (!key || key == tombstone)
3759                                 continue;
3760
3761                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3762                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3763                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3764
3765                         if (sgen_is_object_alive_for_current_gen (key)) {
3766                                 char *value = cur->value;
3767
3768                                 copy_func ((void**)&cur->key, queue);
3769                                 if (value) {
3770                                         if (!sgen_is_object_alive_for_current_gen (value))
3771                                                 nothing_marked = 0;
3772                                         copy_func ((void**)&cur->value, queue);
3773                                 }
3774                         }
3775                 }
3776         }
3777
3778         SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3779         return nothing_marked;
3780 }
3781
3782 int
3783 mono_gc_invoke_finalizers (void)
3784 {
3785         FinalizeReadyEntry *entry = NULL;
3786         gboolean entry_is_critical = FALSE;
3787         int count = 0;
3788         void *obj;
3789         /* FIXME: batch to reduce lock contention */
3790         while (fin_ready_list || critical_fin_list) {
3791                 LOCK_GC;
3792
3793                 if (entry) {
3794                         FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3795
3796                         /* We have finalized entry in the last
3797                            interation, now we need to remove it from
3798                            the list. */
3799                         if (*list == entry)
3800                                 *list = entry->next;
3801                         else {
3802                                 FinalizeReadyEntry *e = *list;
3803                                 while (e->next != entry)
3804                                         e = e->next;
3805                                 e->next = entry->next;
3806                         }
3807                         sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3808                         entry = NULL;
3809                 }
3810
3811                 /* Now look for the first non-null entry. */
3812                 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3813                         ;
3814                 if (entry) {
3815                         entry_is_critical = FALSE;
3816                 } else {
3817                         entry_is_critical = TRUE;
3818                         for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3819                                 ;
3820                 }
3821
3822                 if (entry) {
3823                         g_assert (entry->object);
3824                         num_ready_finalizers--;
3825                         obj = entry->object;
3826                         entry->object = NULL;
3827                         SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3828                 }
3829
3830                 UNLOCK_GC;
3831
3832                 if (!entry)
3833                         break;
3834
3835                 g_assert (entry->object == NULL);
3836                 count++;
3837                 /* the object is on the stack so it is pinned */
3838                 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3839                 mono_gc_run_finalize (obj, NULL);
3840         }
3841         g_assert (!entry);
3842         return count;
3843 }
3844
3845 gboolean
3846 mono_gc_pending_finalizers (void)
3847 {
3848         return fin_ready_list || critical_fin_list;
3849 }
3850
3851 /*
3852  * ######################################################################
3853  * ########  registered roots support
3854  * ######################################################################
3855  */
3856
3857 /*
3858  * We do not coalesce roots.
3859  */
3860 static int
3861 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3862 {
3863         RootRecord new_root;
3864         int i;
3865         LOCK_GC;
3866         for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3867                 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3868                 /* we allow changing the size and the descriptor (for thread statics etc) */
3869                 if (root) {
3870                         size_t old_size = root->end_root - start;
3871                         root->end_root = start + size;
3872                         g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3873                                           ((root->root_desc == 0) && (descr == NULL)));
3874                         root->root_desc = (mword)descr;
3875                         roots_size += size;
3876                         roots_size -= old_size;
3877                         UNLOCK_GC;
3878                         return TRUE;
3879                 }
3880         }
3881
3882         new_root.end_root = start + size;
3883         new_root.root_desc = (mword)descr;
3884
3885         sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3886         roots_size += size;
3887
3888         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);
3889
3890         UNLOCK_GC;
3891         return TRUE;
3892 }
3893
3894 int
3895 mono_gc_register_root (char *start, size_t size, void *descr)
3896 {
3897         return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3898 }
3899
3900 int
3901 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3902 {
3903         return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3904 }
3905
3906 void
3907 mono_gc_deregister_root (char* addr)
3908 {
3909         int root_type;
3910         RootRecord root;
3911
3912         LOCK_GC;
3913         for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3914                 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3915                         roots_size -= (root.end_root - addr);
3916         }
3917         UNLOCK_GC;
3918 }
3919
3920 /*
3921  * ######################################################################
3922  * ########  Thread handling (stop/start code)
3923  * ######################################################################
3924  */
3925
3926 unsigned int sgen_global_stop_count = 0;
3927
3928 int
3929 sgen_get_current_collection_generation (void)
3930 {
3931         return current_collection_generation;
3932 }
3933
3934 void
3935 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3936 {
3937         gc_callbacks = *callbacks;
3938 }
3939
3940 MonoGCCallbacks *
3941 mono_gc_get_gc_callbacks ()
3942 {
3943         return &gc_callbacks;
3944 }
3945
3946 /* Variables holding start/end nursery so it won't have to be passed at every call */
3947 static void *scan_area_arg_start, *scan_area_arg_end;
3948
3949 void
3950 mono_gc_conservatively_scan_area (void *start, void *end)
3951 {
3952         conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3953 }
3954
3955 void*
3956 mono_gc_scan_object (void *obj)
3957 {
3958         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3959         current_object_ops.copy_or_mark_object (&obj, data->queue);
3960         return obj;
3961 }
3962
3963 /*
3964  * Mark from thread stacks and registers.
3965  */
3966 static void
3967 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3968 {
3969         SgenThreadInfo *info;
3970
3971         scan_area_arg_start = start_nursery;
3972         scan_area_arg_end = end_nursery;
3973
3974         FOREACH_THREAD (info) {
3975                 if (info->skip) {
3976                         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);
3977                         continue;
3978                 }
3979                 if (info->gc_disabled) {
3980                         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);
3981                         continue;
3982                 }
3983
3984                 if (!info->joined_stw) {
3985                         SGEN_LOG (3, "Skipping thread not seen in STW %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3986                         continue;
3987                 }
3988
3989                 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 ());
3990                 if (!info->thread_is_dying) {
3991                         if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3992                                 UserCopyOrMarkData data = { NULL, queue };
3993                                 set_user_copy_or_mark_data (&data);
3994                                 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
3995                                 set_user_copy_or_mark_data (NULL);
3996                         } else if (!precise) {
3997                                 if (!conservative_stack_mark) {
3998                                         fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3999                                         conservative_stack_mark = TRUE;
4000                                 }
4001                                 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
4002                         }
4003                 }
4004
4005                 if (!info->thread_is_dying && !precise) {
4006 #ifdef USE_MONO_CTX
4007                         conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
4008                                 start_nursery, end_nursery, PIN_TYPE_STACK);
4009 #else
4010                         conservatively_pin_objects_from (&info->regs, &info->regs + ARCH_NUM_REGS,
4011                                         start_nursery, end_nursery, PIN_TYPE_STACK);
4012 #endif
4013                 }
4014         } END_FOREACH_THREAD
4015 }
4016
4017 static gboolean
4018 ptr_on_stack (void *ptr)
4019 {
4020         gpointer stack_start = &stack_start;
4021         SgenThreadInfo *info = mono_thread_info_current ();
4022
4023         if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
4024                 return TRUE;
4025         return FALSE;
4026 }
4027
4028 static void*
4029 sgen_thread_register (SgenThreadInfo* info, void *addr)
4030 {
4031         LOCK_GC;
4032 #ifndef HAVE_KW_THREAD
4033         info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
4034
4035         g_assert (!mono_native_tls_get_value (thread_info_key));
4036         mono_native_tls_set_value (thread_info_key, info);
4037 #else
4038         sgen_thread_info = info;
4039 #endif
4040
4041 #if !defined(__MACH__)
4042         info->stop_count = -1;
4043         info->signal = 0;
4044 #endif
4045         info->skip = 0;
4046         info->joined_stw = FALSE;
4047         info->doing_handshake = FALSE;
4048         info->thread_is_dying = FALSE;
4049         info->stack_start = NULL;
4050         info->stopped_ip = NULL;
4051         info->stopped_domain = NULL;
4052 #ifdef USE_MONO_CTX
4053         memset (&info->ctx, 0, sizeof (MonoContext));
4054 #else
4055         memset (&info->regs, 0, sizeof (info->regs));
4056 #endif
4057
4058         sgen_init_tlab_info (info);
4059
4060         binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4061
4062         /* try to get it with attributes first */
4063 #if (defined(HAVE_PTHREAD_GETATTR_NP) || defined(HAVE_PTHREAD_ATTR_GET_NP)) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4064   {
4065      size_t size;
4066      void *sstart;
4067      pthread_attr_t attr;
4068
4069 #if defined(HAVE_PTHREAD_GETATTR_NP)
4070     /* Linux */
4071     pthread_getattr_np (pthread_self (), &attr);
4072 #elif defined(HAVE_PTHREAD_ATTR_GET_NP)
4073     /* BSD */
4074     pthread_attr_init (&attr);
4075     pthread_attr_get_np (pthread_self (), &attr);
4076 #else
4077 #error Cannot determine which API is needed to retrieve pthread attributes.
4078 #endif
4079
4080      pthread_attr_getstack (&attr, &sstart, &size);
4081      info->stack_start_limit = sstart;
4082      info->stack_end = (char*)sstart + size;
4083      pthread_attr_destroy (&attr);
4084   }
4085 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4086                  info->stack_end = (char*)pthread_get_stackaddr_np (pthread_self ());
4087                  info->stack_start_limit = (char*)info->stack_end - pthread_get_stacksize_np (pthread_self ());
4088 #else
4089         {
4090                 /* FIXME: we assume the stack grows down */
4091                 gsize stack_bottom = (gsize)addr;
4092                 stack_bottom += 4095;
4093                 stack_bottom &= ~4095;
4094                 info->stack_end = (char*)stack_bottom;
4095         }
4096 #endif
4097
4098 #ifdef HAVE_KW_THREAD
4099         stack_end = info->stack_end;
4100 #endif
4101
4102         SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
4103
4104         if (gc_callbacks.thread_attach_func)
4105                 info->runtime_data = gc_callbacks.thread_attach_func ();
4106
4107         UNLOCK_GC;
4108         return info;
4109 }
4110
4111 static void
4112 sgen_thread_unregister (SgenThreadInfo *p)
4113 {
4114         /* If a delegate is passed to native code and invoked on a thread we dont
4115          * know about, the jit will register it with mono_jit_thread_attach, but
4116          * we have no way of knowing when that thread goes away.  SGen has a TSD
4117          * so we assume that if the domain is still registered, we can detach
4118          * the thread
4119          */
4120         if (mono_domain_get ())
4121                 mono_thread_detach (mono_thread_current ());
4122
4123         p->thread_is_dying = TRUE;
4124
4125         /*
4126         There is a race condition between a thread finishing executing and been removed
4127         from the GC thread set.
4128         This happens on posix systems when TLS data is been cleaned-up, libpthread will
4129         set the thread_info slot to NULL before calling the cleanup function. This
4130         opens a window in which the thread is registered but has a NULL TLS.
4131
4132         The suspend signal handler needs TLS data to know where to store thread state
4133         data or otherwise it will simply ignore the thread.
4134
4135         This solution works because the thread doing STW will wait until all threads been
4136         suspended handshake back, so there is no race between the doing_hankshake test
4137         and the suspend_thread call.
4138
4139         This is not required on systems that do synchronous STW as those can deal with
4140         the above race at suspend time.
4141
4142         FIXME: I believe we could avoid this by using mono_thread_info_lookup when
4143         mono_thread_info_current returns NULL. Or fix mono_thread_info_lookup to do so.
4144         */
4145 #if (defined(__MACH__) && MONO_MACH_ARCH_SUPPORTED) || !defined(HAVE_PTHREAD_KILL)
4146         LOCK_GC;
4147 #else
4148         while (!TRYLOCK_GC) {
4149                 if (!sgen_park_current_thread_if_doing_handshake (p))
4150                         g_usleep (50);
4151         }
4152         MONO_GC_LOCKED ();
4153 #endif
4154
4155         binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4156         SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)mono_thread_info_get_tid (p));
4157
4158         if (gc_callbacks.thread_detach_func) {
4159                 gc_callbacks.thread_detach_func (p->runtime_data);
4160                 p->runtime_data = NULL;
4161         }
4162
4163         mono_threads_unregister_current_thread (p);
4164         UNLOCK_GC;
4165 }
4166
4167
4168 static void
4169 sgen_thread_attach (SgenThreadInfo *info)
4170 {
4171         LOCK_GC;
4172         /*this is odd, can we get attached before the gc is inited?*/
4173         init_stats ();
4174         UNLOCK_GC;
4175
4176         if (gc_callbacks.thread_attach_func && !info->runtime_data)
4177                 info->runtime_data = gc_callbacks.thread_attach_func ();
4178 }
4179 gboolean
4180 mono_gc_register_thread (void *baseptr)
4181 {
4182         return mono_thread_info_attach (baseptr) != NULL;
4183 }
4184
4185 /*
4186  * mono_gc_set_stack_end:
4187  *
4188  *   Set the end of the current threads stack to STACK_END. The stack space between
4189  * STACK_END and the real end of the threads stack will not be scanned during collections.
4190  */
4191 void
4192 mono_gc_set_stack_end (void *stack_end)
4193 {
4194         SgenThreadInfo *info;
4195
4196         LOCK_GC;
4197         info = mono_thread_info_current ();
4198         if (info) {
4199                 g_assert (stack_end < info->stack_end);
4200                 info->stack_end = stack_end;
4201         }
4202         UNLOCK_GC;
4203 }
4204
4205 #if USE_PTHREAD_INTERCEPT
4206
4207
4208 int
4209 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4210 {
4211         return pthread_create (new_thread, attr, start_routine, arg);
4212 }
4213
4214 int
4215 mono_gc_pthread_join (pthread_t thread, void **retval)
4216 {
4217         return pthread_join (thread, retval);
4218 }
4219
4220 int
4221 mono_gc_pthread_detach (pthread_t thread)
4222 {
4223         return pthread_detach (thread);
4224 }
4225
4226 void
4227 mono_gc_pthread_exit (void *retval)
4228 {
4229         pthread_exit (retval);
4230 }
4231
4232 #endif /* USE_PTHREAD_INTERCEPT */
4233
4234 /*
4235  * ######################################################################
4236  * ########  Write barriers
4237  * ######################################################################
4238  */
4239
4240 /*
4241  * Note: the write barriers first do the needed GC work and then do the actual store:
4242  * this way the value is visible to the conservative GC scan after the write barrier
4243  * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4244  * the conservative scan, otherwise by the remembered set scan.
4245  */
4246 void
4247 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4248 {
4249         HEAVY_STAT (++stat_wbarrier_set_field);
4250         if (ptr_in_nursery (field_ptr)) {
4251                 *(void**)field_ptr = value;
4252                 return;
4253         }
4254         SGEN_LOG (8, "Adding remset at %p", field_ptr);
4255         if (value)
4256                 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4257
4258         remset.wbarrier_set_field (obj, field_ptr, value);
4259 }
4260
4261 void
4262 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4263 {
4264         HEAVY_STAT (++stat_wbarrier_set_arrayref);
4265         if (ptr_in_nursery (slot_ptr)) {
4266                 *(void**)slot_ptr = value;
4267                 return;
4268         }
4269         SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4270         if (value)
4271                 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4272
4273         remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4274 }
4275
4276 void
4277 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4278 {
4279         HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4280         /*This check can be done without taking a lock since dest_ptr array is pinned*/
4281         if (ptr_in_nursery (dest_ptr) || count <= 0) {
4282                 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4283                 return;
4284         }
4285
4286 #ifdef SGEN_BINARY_PROTOCOL
4287         {
4288                 int i;
4289                 for (i = 0; i < count; ++i) {
4290                         gpointer dest = (gpointer*)dest_ptr + i;
4291                         gpointer obj = *((gpointer*)src_ptr + i);
4292                         if (obj)
4293                                 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4294                 }
4295         }
4296 #endif
4297
4298         remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4299 }
4300
4301 static char *found_obj;
4302
4303 static void
4304 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4305 {
4306         char *ptr = user_data;
4307
4308         if (ptr >= obj && ptr < obj + size) {
4309                 g_assert (!found_obj);
4310                 found_obj = obj;
4311         }
4312 }
4313
4314 /* for use in the debugger */
4315 char* find_object_for_ptr (char *ptr);
4316 char*
4317 find_object_for_ptr (char *ptr)
4318 {
4319         if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4320                 found_obj = NULL;
4321                 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4322                                 find_object_for_ptr_callback, ptr, TRUE);
4323                 if (found_obj)
4324                         return found_obj;
4325         }
4326
4327         found_obj = NULL;
4328         sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4329         if (found_obj)
4330                 return found_obj;
4331
4332         /*
4333          * Very inefficient, but this is debugging code, supposed to
4334          * be called from gdb, so we don't care.
4335          */
4336         found_obj = NULL;
4337         major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4338         return found_obj;
4339 }
4340
4341 void
4342 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4343 {
4344         gpointer obj;
4345
4346         HEAVY_STAT (++stat_wbarrier_generic_store);
4347
4348 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4349         /* FIXME: ptr_in_heap must be called with the GC lock held */
4350         if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4351                 char *start = find_object_for_ptr (ptr);
4352                 MonoObject *value = *(MonoObject**)ptr;
4353                 LOCK_GC;
4354                 g_assert (start);
4355                 if (start) {
4356                         MonoObject *obj = (MonoObject*)start;
4357                         if (obj->vtable->domain != value->vtable->domain)
4358                                 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4359                 }
4360                 UNLOCK_GC;
4361         }
4362 #endif
4363
4364         obj = *(gpointer*)ptr;
4365         if (obj)
4366                 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4367
4368         if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4369                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4370                 return;
4371         }
4372
4373         /*
4374          * We need to record old->old pointer locations for the
4375          * concurrent collector.
4376          */
4377         if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4378                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4379                 return;
4380         }
4381
4382         SGEN_LOG (8, "Adding remset at %p", ptr);
4383
4384         remset.wbarrier_generic_nostore (ptr);
4385 }
4386
4387 void
4388 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4389 {
4390         SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4391         *(void**)ptr = value;
4392         if (ptr_in_nursery (value))
4393                 mono_gc_wbarrier_generic_nostore (ptr);
4394         sgen_dummy_use (value);
4395 }
4396
4397 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4398 {
4399         mword *dest = _dest;
4400         mword *src = _src;
4401
4402         while (size) {
4403                 if (bitmap & 0x1)
4404                         mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4405                 else
4406                         *dest = *src;
4407                 ++src;
4408                 ++dest;
4409                 size -= SIZEOF_VOID_P;
4410                 bitmap >>= 1;
4411         }
4412 }
4413
4414 #ifdef SGEN_BINARY_PROTOCOL
4415 #undef HANDLE_PTR
4416 #define HANDLE_PTR(ptr,obj) do {                                        \
4417                 gpointer o = *(gpointer*)(ptr);                         \
4418                 if ((o)) {                                              \
4419                         gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4420                         binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4421                 }                                                       \
4422         } while (0)
4423
4424 static void
4425 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4426 {
4427 #define SCAN_OBJECT_NOVTABLE
4428 #include "sgen-scan-object.h"
4429 }
4430 #endif
4431
4432 void
4433 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4434 {
4435         HEAVY_STAT (++stat_wbarrier_value_copy);
4436         g_assert (klass->valuetype);
4437
4438         SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4439
4440         if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4441                 size_t element_size = mono_class_value_size (klass, NULL);
4442                 size_t size = count * element_size;
4443                 mono_gc_memmove (dest, src, size);
4444                 return;
4445         }
4446
4447 #ifdef SGEN_BINARY_PROTOCOL
4448         {
4449                 size_t element_size = mono_class_value_size (klass, NULL);
4450                 int i;
4451                 for (i = 0; i < count; ++i) {
4452                         scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4453                                         (char*)src + i * element_size - sizeof (MonoObject),
4454                                         (mword) klass->gc_descr);
4455                 }
4456         }
4457 #endif
4458
4459         remset.wbarrier_value_copy (dest, src, count, klass);
4460 }
4461
4462 /**
4463  * mono_gc_wbarrier_object_copy:
4464  *
4465  * Write barrier to call when obj is the result of a clone or copy of an object.
4466  */
4467 void
4468 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4469 {
4470         int size;
4471
4472         HEAVY_STAT (++stat_wbarrier_object_copy);
4473
4474         if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4475                 size = mono_object_class (obj)->instance_size;
4476                 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4477                                 size - sizeof (MonoObject));
4478                 return;
4479         }
4480
4481 #ifdef SGEN_BINARY_PROTOCOL
4482         scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4483 #endif
4484
4485         remset.wbarrier_object_copy (obj, src);
4486 }
4487
4488
4489 /*
4490  * ######################################################################
4491  * ########  Other mono public interface functions.
4492  * ######################################################################
4493  */
4494
4495 #define REFS_SIZE 128
4496 typedef struct {
4497         void *data;
4498         MonoGCReferences callback;
4499         int flags;
4500         int count;
4501         int called;
4502         MonoObject *refs [REFS_SIZE];
4503         uintptr_t offsets [REFS_SIZE];
4504 } HeapWalkInfo;
4505
4506 #undef HANDLE_PTR
4507 #define HANDLE_PTR(ptr,obj)     do {    \
4508                 if (*(ptr)) {   \
4509                         if (hwi->count == REFS_SIZE) {  \
4510                                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);    \
4511                                 hwi->count = 0; \
4512                                 hwi->called = 1;        \
4513                         }       \
4514                         hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start;  \
4515                         hwi->refs [hwi->count++] = *(ptr);      \
4516                 }       \
4517         } while (0)
4518
4519 static void
4520 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4521 {
4522 #include "sgen-scan-object.h"
4523 }
4524
4525 static void
4526 walk_references (char *start, size_t size, void *data)
4527 {
4528         HeapWalkInfo *hwi = data;
4529         hwi->called = 0;
4530         hwi->count = 0;
4531         collect_references (hwi, start, size);
4532         if (hwi->count || !hwi->called)
4533                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4534 }
4535
4536 /**
4537  * mono_gc_walk_heap:
4538  * @flags: flags for future use
4539  * @callback: a function pointer called for each object in the heap
4540  * @data: a user data pointer that is passed to callback
4541  *
4542  * This function can be used to iterate over all the live objects in the heap:
4543  * for each object, @callback is invoked, providing info about the object's
4544  * location in memory, its class, its size and the objects it references.
4545  * For each referenced object it's offset from the object address is
4546  * reported in the offsets array.
4547  * The object references may be buffered, so the callback may be invoked
4548  * multiple times for the same object: in all but the first call, the size
4549  * argument will be zero.
4550  * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4551  * profiler event handler.
4552  *
4553  * Returns: a non-zero value if the GC doesn't support heap walking
4554  */
4555 int
4556 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4557 {
4558         HeapWalkInfo hwi;
4559
4560         hwi.flags = flags;
4561         hwi.callback = callback;
4562         hwi.data = data;
4563
4564         sgen_clear_nursery_fragments ();
4565         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4566
4567         major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4568         sgen_los_iterate_objects (walk_references, &hwi);
4569
4570         return 0;
4571 }
4572
4573 void
4574 mono_gc_collect (int generation)
4575 {
4576         LOCK_GC;
4577         if (generation > 1)
4578                 generation = 1;
4579         sgen_perform_collection (0, generation, "user request", TRUE);
4580         UNLOCK_GC;
4581 }
4582
4583 int
4584 mono_gc_max_generation (void)
4585 {
4586         return 1;
4587 }
4588
4589 int
4590 mono_gc_collection_count (int generation)
4591 {
4592         if (generation == 0)
4593                 return stat_minor_gcs;
4594         return stat_major_gcs;
4595 }
4596
4597 int64_t
4598 mono_gc_get_used_size (void)
4599 {
4600         gint64 tot = 0;
4601         LOCK_GC;
4602         tot = los_memory_usage;
4603         tot += nursery_section->next_data - nursery_section->data;
4604         tot += major_collector.get_used_size ();
4605         /* FIXME: account for pinned objects */
4606         UNLOCK_GC;
4607         return tot;
4608 }
4609
4610 int
4611 mono_gc_get_los_limit (void)
4612 {
4613         return MAX_SMALL_OBJ_SIZE;
4614 }
4615
4616 gboolean
4617 mono_gc_user_markers_supported (void)
4618 {
4619         return TRUE;
4620 }
4621
4622 gboolean
4623 mono_object_is_alive (MonoObject* o)
4624 {
4625         return TRUE;
4626 }
4627
4628 int
4629 mono_gc_get_generation (MonoObject *obj)
4630 {
4631         if (ptr_in_nursery (obj))
4632                 return 0;
4633         return 1;
4634 }
4635
4636 void
4637 mono_gc_enable_events (void)
4638 {
4639 }
4640
4641 void
4642 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4643 {
4644         sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4645 }
4646
4647 void
4648 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4649 {
4650         sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4651 }
4652
4653 MonoObject*
4654 mono_gc_weak_link_get (void **link_addr)
4655 {
4656         void * volatile *link_addr_volatile;
4657         void *ptr;
4658         MonoObject *obj;
4659  retry:
4660         link_addr_volatile = link_addr;
4661         ptr = (void*)*link_addr_volatile;
4662         /*
4663          * At this point we have a hidden pointer.  If the GC runs
4664          * here, it will not recognize the hidden pointer as a
4665          * reference, and if the object behind it is not referenced
4666          * elsewhere, it will be freed.  Once the world is restarted
4667          * we reveal the pointer, giving us a pointer to a freed
4668          * object.  To make sure we don't return it, we load the
4669          * hidden pointer again.  If it's still the same, we can be
4670          * sure the object reference is valid.
4671          */
4672         if (ptr)
4673                 obj = (MonoObject*) REVEAL_POINTER (ptr);
4674         else
4675                 return NULL;
4676
4677         mono_memory_barrier ();
4678
4679         /*
4680          * During the second bridge processing step the world is
4681          * running again.  That step processes all weak links once
4682          * more to null those that refer to dead objects.  Before that
4683          * is completed, those links must not be followed, so we
4684          * conservatively wait for bridge processing when any weak
4685          * link is dereferenced.
4686          */
4687         if (G_UNLIKELY (bridge_processing_in_progress))
4688                 mono_gc_wait_for_bridge_processing ();
4689
4690         if ((void*)*link_addr_volatile != ptr)
4691                 goto retry;
4692
4693         return obj;
4694 }
4695
4696 gboolean
4697 mono_gc_ephemeron_array_add (MonoObject *obj)
4698 {
4699         EphemeronLinkNode *node;
4700
4701         LOCK_GC;
4702
4703         node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4704         if (!node) {
4705                 UNLOCK_GC;
4706                 return FALSE;
4707         }
4708         node->array = (char*)obj;
4709         node->next = ephemeron_list;
4710         ephemeron_list = node;
4711
4712         SGEN_LOG (5, "Registered ephemeron array %p", obj);
4713
4714         UNLOCK_GC;
4715         return TRUE;
4716 }
4717
4718 gboolean
4719 mono_gc_set_allow_synchronous_major (gboolean flag)
4720 {
4721         if (!major_collector.is_concurrent)
4722                 return flag;
4723
4724         allow_synchronous_major = flag;
4725         return TRUE;
4726 }
4727
4728 void*
4729 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4730 {
4731         void *result;
4732         LOCK_INTERRUPTION;
4733         result = func (data);
4734         UNLOCK_INTERRUPTION;
4735         return result;
4736 }
4737
4738 gboolean
4739 mono_gc_is_gc_thread (void)
4740 {
4741         gboolean result;
4742         LOCK_GC;
4743         result = mono_thread_info_current () != NULL;
4744         UNLOCK_GC;
4745         return result;
4746 }
4747
4748 static gboolean
4749 is_critical_method (MonoMethod *method)
4750 {
4751         return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4752 }
4753
4754 void
4755 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4756 {
4757         va_list ap;
4758
4759         va_start (ap, description_format);
4760
4761         fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4762         vfprintf (stderr, description_format, ap);
4763         if (fallback)
4764                 fprintf (stderr, " - %s", fallback);
4765         fprintf (stderr, "\n");
4766
4767         va_end (ap);
4768 }
4769
4770 static gboolean
4771 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4772 {
4773         char *endptr;
4774         double val = strtod (opt, &endptr);
4775         if (endptr == opt) {
4776                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4777                 return FALSE;
4778         }
4779         else if (val < min || val > max) {
4780                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4781                 return FALSE;
4782         }
4783         *result = val;
4784         return TRUE;
4785 }
4786
4787 void
4788 mono_gc_base_init (void)
4789 {
4790         MonoThreadInfoCallbacks cb;
4791         char *env;
4792         char **opts, **ptr;
4793         char *major_collector_opt = NULL;
4794         char *minor_collector_opt = NULL;
4795         glong max_heap = 0;
4796         glong soft_limit = 0;
4797         int num_workers;
4798         int result;
4799         int dummy;
4800         gboolean debug_print_allowance = FALSE;
4801         double allowance_ratio = 0, save_target = 0;
4802         gboolean have_split_nursery = FALSE;
4803         gboolean cement_enabled = TRUE;
4804
4805         do {
4806                 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4807                 switch (result) {
4808                 case 1:
4809                         /* already inited */
4810                         return;
4811                 case -1:
4812                         /* being inited by another thread */
4813                         g_usleep (1000);
4814                         break;
4815                 case 0:
4816                         /* we will init it */
4817                         break;
4818                 default:
4819                         g_assert_not_reached ();
4820                 }
4821         } while (result != 0);
4822
4823         LOCK_INIT (gc_mutex);
4824
4825         pagesize = mono_pagesize ();
4826         gc_debug_file = stderr;
4827
4828         cb.thread_register = sgen_thread_register;
4829         cb.thread_unregister = sgen_thread_unregister;
4830         cb.thread_attach = sgen_thread_attach;
4831         cb.mono_method_is_critical = (gpointer)is_critical_method;
4832 #ifndef HOST_WIN32
4833         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4834 #endif
4835
4836         mono_threads_init (&cb, sizeof (SgenThreadInfo));
4837
4838         LOCK_INIT (sgen_interruption_mutex);
4839         LOCK_INIT (pin_queue_mutex);
4840
4841         init_user_copy_or_mark_key ();
4842
4843         if ((env = getenv (MONO_GC_PARAMS_NAME))) {
4844                 opts = g_strsplit (env, ",", -1);
4845                 for (ptr = opts; *ptr; ++ptr) {
4846                         char *opt = *ptr;
4847                         if (g_str_has_prefix (opt, "major=")) {
4848                                 opt = strchr (opt, '=') + 1;
4849                                 major_collector_opt = g_strdup (opt);
4850                         } else if (g_str_has_prefix (opt, "minor=")) {
4851                                 opt = strchr (opt, '=') + 1;
4852                                 minor_collector_opt = g_strdup (opt);
4853                         }
4854                 }
4855         } else {
4856                 opts = NULL;
4857         }
4858
4859         init_stats ();
4860         sgen_init_internal_allocator ();
4861         sgen_init_nursery_allocator ();
4862
4863         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4864         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4865         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4866         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4867
4868 #ifndef HAVE_KW_THREAD
4869         mono_native_tls_alloc (&thread_info_key, NULL);
4870 #endif
4871
4872         /*
4873          * This needs to happen before any internal allocations because
4874          * it inits the small id which is required for hazard pointer
4875          * operations.
4876          */
4877         sgen_os_init ();
4878
4879         mono_thread_info_attach (&dummy);
4880
4881         if (!minor_collector_opt) {
4882                 sgen_simple_nursery_init (&sgen_minor_collector);
4883         } else {
4884                 if (!strcmp (minor_collector_opt, "simple")) {
4885                 use_simple_nursery:
4886                         sgen_simple_nursery_init (&sgen_minor_collector);
4887                 } else if (!strcmp (minor_collector_opt, "split")) {
4888                         sgen_split_nursery_init (&sgen_minor_collector);
4889                         have_split_nursery = TRUE;
4890                 } else {
4891                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4892                         goto use_simple_nursery;
4893                 }
4894         }
4895
4896         if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4897         use_marksweep_major:
4898                 sgen_marksweep_init (&major_collector);
4899         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4900                 sgen_marksweep_fixed_init (&major_collector);
4901         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4902                 sgen_marksweep_par_init (&major_collector);
4903         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4904                 sgen_marksweep_fixed_par_init (&major_collector);
4905         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4906                 sgen_marksweep_conc_init (&major_collector);
4907         } else {
4908                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4909                 goto use_marksweep_major;
4910         }
4911
4912         if (have_split_nursery && major_collector.is_parallel) {
4913                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4914                 have_split_nursery = FALSE;
4915         }
4916
4917         num_workers = mono_cpu_count ();
4918         g_assert (num_workers > 0);
4919         if (num_workers > 16)
4920                 num_workers = 16;
4921
4922         ///* Keep this the default for now */
4923         /* Precise marking is broken on all supported targets. Disable until fixed. */
4924         conservative_stack_mark = TRUE;
4925
4926         sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4927
4928         if (opts) {
4929                 gboolean usage_printed = FALSE;
4930
4931                 for (ptr = opts; *ptr; ++ptr) {
4932                         char *opt = *ptr;
4933                         if (!strcmp (opt, ""))
4934                                 continue;
4935                         if (g_str_has_prefix (opt, "major="))
4936                                 continue;
4937                         if (g_str_has_prefix (opt, "minor="))
4938                                 continue;
4939                         if (g_str_has_prefix (opt, "max-heap-size=")) {
4940                                 glong max_heap_candidate = 0;
4941                                 opt = strchr (opt, '=') + 1;
4942                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4943                                         max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(glong)(mono_pagesize () - 1);
4944                                         if (max_heap != max_heap_candidate)
4945                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4946                                 } else {
4947                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4948                                 }
4949                                 continue;
4950                         }
4951                         if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4952                                 opt = strchr (opt, '=') + 1;
4953                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4954                                         if (soft_limit <= 0) {
4955                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4956                                                 soft_limit = 0;
4957                                         }
4958                                 } else {
4959                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4960                                 }
4961                                 continue;
4962                         }
4963                         if (g_str_has_prefix (opt, "workers=")) {
4964                                 long val;
4965                                 char *endptr;
4966                                 if (!major_collector.is_parallel) {
4967                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
4968                                         continue;
4969                                 }
4970                                 opt = strchr (opt, '=') + 1;
4971                                 val = strtol (opt, &endptr, 10);
4972                                 if (!*opt || *endptr) {
4973                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
4974                                         continue;
4975                                 }
4976                                 if (val <= 0 || val > 16) {
4977                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
4978                                         continue;
4979                                 }
4980                                 num_workers = (int)val;
4981                                 continue;
4982                         }
4983                         if (g_str_has_prefix (opt, "stack-mark=")) {
4984                                 opt = strchr (opt, '=') + 1;
4985                                 if (!strcmp (opt, "precise")) {
4986                                         conservative_stack_mark = FALSE;
4987                                 } else if (!strcmp (opt, "conservative")) {
4988                                         conservative_stack_mark = TRUE;
4989                                 } else {
4990                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4991                                                         "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4992                                 }
4993                                 continue;
4994                         }
4995                         if (g_str_has_prefix (opt, "bridge=")) {
4996                                 opt = strchr (opt, '=') + 1;
4997                                 sgen_register_test_bridge_callbacks (g_strdup (opt));
4998                                 continue;
4999                         }
5000 #ifdef USER_CONFIG
5001                         if (g_str_has_prefix (opt, "nursery-size=")) {
5002                                 long val;
5003                                 opt = strchr (opt, '=') + 1;
5004                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
5005 #ifdef SGEN_ALIGN_NURSERY
5006                                         if ((val & (val - 1))) {
5007                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
5008                                                 continue;
5009                                         }
5010
5011                                         if (val < SGEN_MAX_NURSERY_WASTE) {
5012                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
5013                                                                 "`nursery-size` must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
5014                                                 continue;
5015                                         }
5016
5017                                         sgen_nursery_size = val;
5018                                         sgen_nursery_bits = 0;
5019                                         while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
5020                                                 ;
5021 #else
5022                                         sgen_nursery_size = val;
5023 #endif
5024                                 } else {
5025                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
5026                                         continue;
5027                                 }
5028                                 continue;
5029                         }
5030 #endif
5031                         if (g_str_has_prefix (opt, "save-target-ratio=")) {
5032                                 double val;
5033                                 opt = strchr (opt, '=') + 1;
5034                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
5035                                                 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
5036                                         save_target = val;
5037                                 }
5038                                 continue;
5039                         }
5040                         if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
5041                                 double val;
5042                                 opt = strchr (opt, '=') + 1;
5043                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
5044                                                 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
5045                                         allowance_ratio = val;
5046                                 }
5047                                 continue;
5048                         }
5049                         if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
5050                                 if (!major_collector.is_concurrent) {
5051                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
5052                                         continue;
5053                                 }
5054
5055                                 opt = strchr (opt, '=') + 1;
5056
5057                                 if (!strcmp (opt, "yes")) {
5058                                         allow_synchronous_major = TRUE;
5059                                 } else if (!strcmp (opt, "no")) {
5060                                         allow_synchronous_major = FALSE;
5061                                 } else {
5062                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
5063                                         continue;
5064                                 }
5065                         }
5066
5067                         if (!strcmp (opt, "cementing")) {
5068                                 cement_enabled = TRUE;
5069                                 continue;
5070                         }
5071                         if (!strcmp (opt, "no-cementing")) {
5072                                 cement_enabled = FALSE;
5073                                 continue;
5074                         }
5075
5076                         if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
5077                                 continue;
5078
5079                         if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
5080                                 continue;
5081
5082                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5083
5084                         if (usage_printed)
5085                                 continue;
5086
5087                         fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
5088                         fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5089                         fprintf (stderr, "  soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
5090                         fprintf (stderr, "  nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5091                         fprintf (stderr, "  major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
5092                         fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
5093                         fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
5094                         fprintf (stderr, "  stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
5095                         fprintf (stderr, "  [no-]cementing\n");
5096                         if (major_collector.is_concurrent)
5097                                 fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
5098                         if (major_collector.print_gc_param_usage)
5099                                 major_collector.print_gc_param_usage ();
5100                         if (sgen_minor_collector.print_gc_param_usage)
5101                                 sgen_minor_collector.print_gc_param_usage ();
5102                         fprintf (stderr, " Experimental options:\n");
5103                         fprintf (stderr, "  save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
5104                         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);
5105                         fprintf (stderr, "\n");
5106
5107                         usage_printed = TRUE;
5108                 }
5109                 g_strfreev (opts);
5110         }
5111
5112         if (major_collector.is_parallel)
5113                 sgen_workers_init (num_workers);
5114         else if (major_collector.is_concurrent)
5115                 sgen_workers_init (1);
5116
5117         if (major_collector_opt)
5118                 g_free (major_collector_opt);
5119
5120         if (minor_collector_opt)
5121                 g_free (minor_collector_opt);
5122
5123         alloc_nursery ();
5124
5125         sgen_cement_init (cement_enabled);
5126
5127         if ((env = getenv (MONO_GC_DEBUG_NAME))) {
5128                 gboolean usage_printed = FALSE;
5129
5130                 opts = g_strsplit (env, ",", -1);
5131                 for (ptr = opts; ptr && *ptr; ptr ++) {
5132                         char *opt = *ptr;
5133                         if (!strcmp (opt, ""))
5134                                 continue;
5135                         if (opt [0] >= '0' && opt [0] <= '9') {
5136                                 gc_debug_level = atoi (opt);
5137                                 opt++;
5138                                 if (opt [0] == ':')
5139                                         opt++;
5140                                 if (opt [0]) {
5141 #ifdef HOST_WIN32
5142                                         char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
5143 #else
5144                                         char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
5145 #endif
5146                                         gc_debug_file = fopen (rf, "wb");
5147                                         if (!gc_debug_file)
5148                                                 gc_debug_file = stderr;
5149                                         g_free (rf);
5150                                 }
5151                         } else if (!strcmp (opt, "print-allowance")) {
5152                                 debug_print_allowance = TRUE;
5153                         } else if (!strcmp (opt, "print-pinning")) {
5154                                 do_pin_stats = TRUE;
5155                         } else if (!strcmp (opt, "verify-before-allocs")) {
5156                                 verify_before_allocs = 1;
5157                                 has_per_allocation_action = TRUE;
5158                         } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5159                                 char *arg = strchr (opt, '=') + 1;
5160                                 verify_before_allocs = atoi (arg);
5161                                 has_per_allocation_action = TRUE;
5162                         } else if (!strcmp (opt, "collect-before-allocs")) {
5163                                 collect_before_allocs = 1;
5164                                 has_per_allocation_action = TRUE;
5165                         } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5166                                 char *arg = strchr (opt, '=') + 1;
5167                                 has_per_allocation_action = TRUE;
5168                                 collect_before_allocs = atoi (arg);
5169                         } else if (!strcmp (opt, "verify-before-collections")) {
5170                                 whole_heap_check_before_collection = TRUE;
5171                         } else if (!strcmp (opt, "check-at-minor-collections")) {
5172                                 consistency_check_at_minor_collection = TRUE;
5173                                 nursery_clear_policy = CLEAR_AT_GC;
5174                         } else if (!strcmp (opt, "check-mark-bits")) {
5175                                 check_mark_bits_after_major_collection = TRUE;
5176                         } else if (!strcmp (opt, "check-nursery-pinned")) {
5177                                 check_nursery_objects_pinned = TRUE;
5178                         } else if (!strcmp (opt, "xdomain-checks")) {
5179                                 xdomain_checks = TRUE;
5180                         } else if (!strcmp (opt, "clear-at-gc")) {
5181                                 nursery_clear_policy = CLEAR_AT_GC;
5182                         } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5183                                 nursery_clear_policy = CLEAR_AT_GC;
5184                         } else if (!strcmp (opt, "check-scan-starts")) {
5185                                 do_scan_starts_check = TRUE;
5186                         } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5187                                 do_verify_nursery = TRUE;
5188                         } else if (!strcmp (opt, "check-concurrent")) {
5189                                 if (!major_collector.is_concurrent) {
5190                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5191                                         continue;
5192                                 }
5193                                 do_concurrent_checks = TRUE;
5194                         } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5195                                 do_dump_nursery_content = TRUE;
5196                         } else if (!strcmp (opt, "no-managed-allocator")) {
5197                                 sgen_set_use_managed_allocator (FALSE);
5198                         } else if (!strcmp (opt, "disable-minor")) {
5199                                 disable_minor_collections = TRUE;
5200                         } else if (!strcmp (opt, "disable-major")) {
5201                                 disable_major_collections = TRUE;
5202                         } else if (g_str_has_prefix (opt, "heap-dump=")) {
5203                                 char *filename = strchr (opt, '=') + 1;
5204                                 nursery_clear_policy = CLEAR_AT_GC;
5205                                 heap_dump_file = fopen (filename, "w");
5206                                 if (heap_dump_file) {
5207                                         fprintf (heap_dump_file, "<sgen-dump>\n");
5208                                         do_pin_stats = TRUE;
5209                                 }
5210 #ifdef SGEN_BINARY_PROTOCOL
5211                         } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5212                                 char *filename = strchr (opt, '=') + 1;
5213                                 binary_protocol_init (filename);
5214 #endif
5215                         } else {
5216                                 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5217
5218                                 if (usage_printed)
5219                                         continue;
5220
5221                                 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);
5222                                 fprintf (stderr, "Valid <option>s are:\n");
5223                                 fprintf (stderr, "  collect-before-allocs[=<n>]\n");
5224                                 fprintf (stderr, "  verify-before-allocs[=<n>]\n");
5225                                 fprintf (stderr, "  check-at-minor-collections\n");
5226                                 fprintf (stderr, "  check-mark-bits\n");
5227                                 fprintf (stderr, "  check-nursery-pinned\n");
5228                                 fprintf (stderr, "  verify-before-collections\n");
5229                                 fprintf (stderr, "  verify-nursery-at-minor-gc\n");
5230                                 fprintf (stderr, "  dump-nursery-at-minor-gc\n");
5231                                 fprintf (stderr, "  disable-minor\n");
5232                                 fprintf (stderr, "  disable-major\n");
5233                                 fprintf (stderr, "  xdomain-checks\n");
5234                                 fprintf (stderr, "  check-concurrent\n");
5235                                 fprintf (stderr, "  clear-at-gc\n");
5236                                 fprintf (stderr, "  clear-nursery-at-gc\n");
5237                                 fprintf (stderr, "  check-scan-starts\n");
5238                                 fprintf (stderr, "  no-managed-allocator\n");
5239                                 fprintf (stderr, "  print-allowance\n");
5240                                 fprintf (stderr, "  print-pinning\n");
5241                                 fprintf (stderr, "  heap-dump=<filename>\n");
5242 #ifdef SGEN_BINARY_PROTOCOL
5243                                 fprintf (stderr, "  binary-protocol=<filename>\n");
5244 #endif
5245                                 fprintf (stderr, "\n");
5246
5247                                 usage_printed = TRUE;
5248                         }
5249                 }
5250                 g_strfreev (opts);
5251         }
5252
5253         if (major_collector.is_parallel) {
5254                 if (heap_dump_file) {
5255                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5256                         fclose (heap_dump_file);
5257                         heap_dump_file = NULL;
5258                 }
5259                 if (do_pin_stats) {
5260                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5261                         do_pin_stats = FALSE;
5262                 }
5263         }
5264
5265         if (major_collector.post_param_init)
5266                 major_collector.post_param_init (&major_collector);
5267
5268         sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5269
5270         memset (&remset, 0, sizeof (remset));
5271
5272         sgen_card_table_init (&remset);
5273
5274         gc_initialized = 1;
5275 }
5276
5277 const char *
5278 mono_gc_get_gc_name (void)
5279 {
5280         return "sgen";
5281 }
5282
5283 static MonoMethod *write_barrier_method;
5284
5285 gboolean
5286 sgen_is_critical_method (MonoMethod *method)
5287 {
5288         return (method == write_barrier_method || sgen_is_managed_allocator (method));
5289 }
5290
5291 gboolean
5292 sgen_has_critical_method (void)
5293 {
5294         return write_barrier_method || sgen_has_managed_allocator ();
5295 }
5296
5297 #ifndef DISABLE_JIT
5298
5299 static void
5300 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5301 {
5302         memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5303 #ifdef SGEN_ALIGN_NURSERY
5304         // if (ptr_in_nursery (ptr)) return;
5305         /*
5306          * Masking out the bits might be faster, but we would have to use 64 bit
5307          * immediates, which might be slower.
5308          */
5309         mono_mb_emit_ldarg (mb, 0);
5310         mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5311         mono_mb_emit_byte (mb, CEE_SHR_UN);
5312         mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5313         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5314
5315         if (!major_collector.is_concurrent) {
5316                 // if (!ptr_in_nursery (*ptr)) return;
5317                 mono_mb_emit_ldarg (mb, 0);
5318                 mono_mb_emit_byte (mb, CEE_LDIND_I);
5319                 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5320                 mono_mb_emit_byte (mb, CEE_SHR_UN);
5321                 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5322                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5323         }
5324 #else
5325         int label_continue1, label_continue2;
5326         int dereferenced_var;
5327
5328         // if (ptr < (sgen_get_nursery_start ())) goto continue;
5329         mono_mb_emit_ldarg (mb, 0);
5330         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5331         label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5332
5333         // if (ptr >= sgen_get_nursery_end ())) goto continue;
5334         mono_mb_emit_ldarg (mb, 0);
5335         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5336         label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5337
5338         // Otherwise return
5339         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5340
5341         // continue:
5342         mono_mb_patch_branch (mb, label_continue_1);
5343         mono_mb_patch_branch (mb, label_continue_2);
5344
5345         // Dereference and store in local var
5346         dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5347         mono_mb_emit_ldarg (mb, 0);
5348         mono_mb_emit_byte (mb, CEE_LDIND_I);
5349         mono_mb_emit_stloc (mb, dereferenced_var);
5350
5351         if (!major_collector.is_concurrent) {
5352                 // if (*ptr < sgen_get_nursery_start ()) return;
5353                 mono_mb_emit_ldloc (mb, dereferenced_var);
5354                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5355                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5356
5357                 // if (*ptr >= sgen_get_nursery_end ()) return;
5358                 mono_mb_emit_ldloc (mb, dereferenced_var);
5359                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5360                 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5361         }
5362 #endif
5363 }
5364 #endif
5365
5366 MonoMethod*
5367 mono_gc_get_write_barrier (void)
5368 {
5369         MonoMethod *res;
5370         MonoMethodBuilder *mb;
5371         MonoMethodSignature *sig;
5372 #ifdef MANAGED_WBARRIER
5373         int i, nursery_check_labels [3];
5374
5375 #ifdef HAVE_KW_THREAD
5376         int stack_end_offset = -1;
5377
5378         MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5379         g_assert (stack_end_offset != -1);
5380 #endif
5381 #endif
5382
5383         // FIXME: Maybe create a separate version for ctors (the branch would be
5384         // correctly predicted more times)
5385         if (write_barrier_method)
5386                 return write_barrier_method;
5387
5388         /* Create the IL version of mono_gc_barrier_generic_store () */
5389         sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5390         sig->ret = &mono_defaults.void_class->byval_arg;
5391         sig->params [0] = &mono_defaults.int_class->byval_arg;
5392
5393         mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5394
5395 #ifndef DISABLE_JIT
5396 #ifdef MANAGED_WBARRIER
5397         emit_nursery_check (mb, nursery_check_labels);
5398         /*
5399         addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5400         *addr = 1;
5401
5402         sgen_cardtable:
5403                 LDC_PTR sgen_cardtable
5404
5405         address >> CARD_BITS
5406                 LDARG_0
5407                 LDC_I4 CARD_BITS
5408                 SHR_UN
5409         if (SGEN_HAVE_OVERLAPPING_CARDS) {
5410                 LDC_PTR card_table_mask
5411                 AND
5412         }
5413         AND
5414         ldc_i4_1
5415         stind_i1
5416         */
5417         mono_mb_emit_ptr (mb, sgen_cardtable);
5418         mono_mb_emit_ldarg (mb, 0);
5419         mono_mb_emit_icon (mb, CARD_BITS);
5420         mono_mb_emit_byte (mb, CEE_SHR_UN);
5421 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5422         mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5423         mono_mb_emit_byte (mb, CEE_AND);
5424 #endif
5425         mono_mb_emit_byte (mb, CEE_ADD);
5426         mono_mb_emit_icon (mb, 1);
5427         mono_mb_emit_byte (mb, CEE_STIND_I1);
5428
5429         // return;
5430         for (i = 0; i < 3; ++i) {
5431                 if (nursery_check_labels [i])
5432                         mono_mb_patch_branch (mb, nursery_check_labels [i]);
5433         }
5434         mono_mb_emit_byte (mb, CEE_RET);
5435 #else
5436         mono_mb_emit_ldarg (mb, 0);
5437         mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5438         mono_mb_emit_byte (mb, CEE_RET);
5439 #endif
5440 #endif
5441         res = mono_mb_create_method (mb, sig, 16);
5442         mono_mb_free (mb);
5443
5444         mono_loader_lock ();
5445         if (write_barrier_method) {
5446                 /* Already created */
5447                 mono_free_method (res);
5448         } else {
5449                 /* double-checked locking */
5450                 mono_memory_barrier ();
5451                 write_barrier_method = res;
5452         }
5453         mono_loader_unlock ();
5454
5455         return write_barrier_method;
5456 }
5457
5458 char*
5459 mono_gc_get_description (void)
5460 {
5461         return g_strdup ("sgen");
5462 }
5463
5464 void
5465 mono_gc_set_desktop_mode (void)
5466 {
5467 }
5468
5469 gboolean
5470 mono_gc_is_moving (void)
5471 {
5472         return TRUE;
5473 }
5474
5475 gboolean
5476 mono_gc_is_disabled (void)
5477 {
5478         return FALSE;
5479 }
5480
5481 #ifdef HOST_WIN32
5482 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5483 {
5484         return TRUE;
5485 }
5486 #endif
5487
5488 NurseryClearPolicy
5489 sgen_get_nursery_clear_policy (void)
5490 {
5491         return nursery_clear_policy;
5492 }
5493
5494 MonoVTable*
5495 sgen_get_array_fill_vtable (void)
5496 {
5497         if (!array_fill_vtable) {
5498                 static MonoClass klass;
5499                 static MonoVTable vtable;
5500                 gsize bmap;
5501
5502                 MonoDomain *domain = mono_get_root_domain ();
5503                 g_assert (domain);
5504
5505                 klass.element_class = mono_defaults.byte_class;
5506                 klass.rank = 1;
5507                 klass.instance_size = sizeof (MonoArray);
5508                 klass.sizes.element_size = 1;
5509                 klass.name = "array_filler_type";
5510
5511                 vtable.klass = &klass;
5512                 bmap = 0;
5513                 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5514                 vtable.rank = 1;
5515
5516                 array_fill_vtable = &vtable;
5517         }
5518         return array_fill_vtable;
5519 }
5520
5521 void
5522 sgen_gc_lock (void)
5523 {
5524         LOCK_GC;
5525 }
5526
5527 void
5528 sgen_gc_unlock (void)
5529 {
5530         UNLOCK_GC;
5531 }
5532
5533 void
5534 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5535 {
5536         major_collector.iterate_live_block_ranges (callback);
5537 }
5538
5539 void
5540 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5541 {
5542         major_collector.scan_card_table (FALSE, queue);
5543 }
5544
5545 SgenMajorCollector*
5546 sgen_get_major_collector (void)
5547 {
5548         return &major_collector;
5549 }
5550
5551 void mono_gc_set_skip_thread (gboolean skip)
5552 {
5553         SgenThreadInfo *info = mono_thread_info_current ();
5554
5555         LOCK_GC;
5556         info->gc_disabled = skip;
5557         UNLOCK_GC;
5558 }
5559
5560 SgenRemeberedSet*
5561 sgen_get_remset (void)
5562 {
5563         return &remset;
5564 }
5565
5566 guint
5567 mono_gc_get_vtable_bits (MonoClass *class)
5568 {
5569         if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5570                 return SGEN_GC_BIT_BRIDGE_OBJECT;
5571         return 0;
5572 }
5573
5574 void
5575 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5576 {
5577         // FIXME:
5578 }
5579
5580
5581 void
5582 sgen_check_whole_heap_stw (void)
5583 {
5584         sgen_stop_world (0);
5585         sgen_clear_nursery_fragments ();
5586         sgen_check_whole_heap (FALSE);
5587         sgen_restart_world (0, NULL);
5588 }
5589
5590 void
5591 sgen_gc_event_moves (void)
5592 {
5593         if (moved_objects_idx) {
5594                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5595                 moved_objects_idx = 0;
5596         }
5597 }
5598
5599 #endif /* HAVE_SGEN_GC */