mono/metadata/sgen-gc.c

   1 /*
   2  * sgen-gc.c: Simple generational GC.
   3  *
   4  * Author:
   5  *      Paolo Molaro (lupus@ximian.com)
   6  *  Rodrigo Kumpera (kumpera@gmail.com)
   7  *
   8  * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
   9  * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
  10  *
  11  * Thread start/stop adapted from Boehm's GC:
  12  * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
  13  * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
  14  * Copyright (c) 1998 by Fergus Henderson.  All rights reserved.
  15  * Copyright (c) 2000-2004 by Hewlett-Packard Company.  All rights reserved.
  16  * Copyright 2001-2003 Ximian, Inc
  17  * Copyright 2003-2010 Novell, Inc.
  18  * Copyright 2011 Xamarin, Inc.
  19  * Copyright (C) 2012 Xamarin Inc
  20  *
  21  * This library is free software; you can redistribute it and/or
  22  * modify it under the terms of the GNU Library General Public
  23  * License 2.0 as published by the Free Software Foundation;
  24  *
  25  * This library is distributed in the hope that it will be useful,
  26  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  28  * Library General Public License for more details.
  29  *
  30  * You should have received a copy of the GNU Library General Public
  31  * License 2.0 along with this library; if not, write to the Free
  32  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  33  *
  34  * Important: allocation provides always zeroed memory, having to do
  35  * a memset after allocation is deadly for performance.
  36  * Memory usage at startup is currently as follows:
  37  * 64 KB pinned space
  38  * 64 KB internal space
  39  * size of nursery
  40  * We should provide a small memory config with half the sizes
  41  *
  42  * We currently try to make as few mono assumptions as possible:
  43  * 1) 2-word header with no GC pointers in it (first vtable, second to store the
  44  *    forwarding ptr)
  45  * 2) gc descriptor is the second word in the vtable (first word in the class)
  46  * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
  47  * 4) there is a function to get an object's size and the number of
  48  *    elements in an array.
  49  * 5) we know the special way bounds are allocated for complex arrays
  50  * 6) we know about proxies and how to treat them when domains are unloaded
  51  *
  52  * Always try to keep stack usage to a minimum: no recursive behaviour
  53  * and no large stack allocs.
  54  *
  55  * General description.
  56  * Objects are initially allocated in a nursery using a fast bump-pointer technique.
  57  * When the nursery is full we start a nursery collection: this is performed with a
  58  * copying GC.
  59  * When the old generation is full we start a copying GC of the old generation as well:
  60  * this will be changed to mark&sweep with copying when fragmentation becomes to severe
  61  * in the future.  Maybe we'll even do both during the same collection like IMMIX.
  62  *
  63  * The things that complicate this description are:
  64  * *) pinned objects: we can't move them so we need to keep track of them
  65  * *) no precise info of the thread stacks and registers: we need to be able to
  66  *    quickly find the objects that may be referenced conservatively and pin them
  67  *    (this makes the first issues more important)
  68  * *) large objects are too expensive to be dealt with using copying GC: we handle them
  69  *    with mark/sweep during major collections
  70  * *) some objects need to not move even if they are small (interned strings, Type handles):
  71  *    we use mark/sweep for them, too: they are not allocated in the nursery, but inside
  72  *    PinnedChunks regions
  73  */
  74
  75 /*
  76  * TODO:
  77
  78  *) we could have a function pointer in MonoClass to implement
  79   customized write barriers for value types
  80
  81  *) investigate the stuff needed to advance a thread to a GC-safe
  82   point (single-stepping, read from unmapped memory etc) and implement it.
  83   This would enable us to inline allocations and write barriers, for example,
  84   or at least parts of them, like the write barrier checks.
  85   We may need this also for handling precise info on stacks, even simple things
  86   as having uninitialized data on the stack and having to wait for the prolog
  87   to zero it. Not an issue for the last frame that we scan conservatively.
  88   We could always not trust the value in the slots anyway.
  89
  90  *) modify the jit to save info about references in stack locations:
  91   this can be done just for locals as a start, so that at least
  92   part of the stack is handled precisely.
  93
  94  *) test/fix endianess issues
  95
  96  *) Implement a card table as the write barrier instead of remembered
  97     sets?  Card tables are not easy to implement with our current
  98     memory layout.  We have several different kinds of major heap
  99     objects: Small objects in regular blocks, small objects in pinned
 100     chunks and LOS objects.  If we just have a pointer we have no way
 101     to tell which kind of object it points into, therefore we cannot
 102     know where its card table is.  The least we have to do to make
 103     this happen is to get rid of write barriers for indirect stores.
 104     (See next item)
 105
 106  *) Get rid of write barriers for indirect stores.  We can do this by
 107     telling the GC to wbarrier-register an object once we do an ldloca
 108     or ldelema on it, and to unregister it once it's not used anymore
 109     (it can only travel downwards on the stack).  The problem with
 110     unregistering is that it needs to happen eventually no matter
 111     what, even if exceptions are thrown, the thread aborts, etc.
 112     Rodrigo suggested that we could do only the registering part and
 113     let the collector find out (pessimistically) when it's safe to
 114     unregister, namely when the stack pointer of the thread that
 115     registered the object is higher than it was when the registering
 116     happened.  This might make for a good first implementation to get
 117     some data on performance.
 118
 119  *) Some sort of blacklist support?  Blacklists is a concept from the
 120     Boehm GC: if during a conservative scan we find pointers to an
 121     area which we might use as heap, we mark that area as unusable, so
 122     pointer retention by random pinning pointers is reduced.
 123
 124  *) experiment with max small object size (very small right now - 2kb,
 125     because it's tied to the max freelist size)
 126
 127   *) add an option to mmap the whole heap in one chunk: it makes for many
 128      simplifications in the checks (put the nursery at the top and just use a single
 129      check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
 130      not flexible (too much of the address space may be used by default or we can't
 131      increase the heap as needed) and we'd need a race-free mechanism to return memory
 132      back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
 133      was written to, munmap is needed, but the following mmap may not find the same segment
 134      free...)
 135
 136  *) memzero the major fragments after restarting the world and optionally a smaller
 137     chunk at a time
 138
 139  *) investigate having fragment zeroing threads
 140
 141  *) separate locks for finalization and other minor stuff to reduce
 142     lock contention
 143
 144  *) try a different copying order to improve memory locality
 145
 146  *) a thread abort after a store but before the write barrier will
 147     prevent the write barrier from executing
 148
 149  *) specialized dynamically generated markers/copiers
 150
 151  *) Dynamically adjust TLAB size to the number of threads.  If we have
 152     too many threads that do allocation, we might need smaller TLABs,
 153     and we might get better performance with larger TLABs if we only
 154     have a handful of threads.  We could sum up the space left in all
 155     assigned TLABs and if that's more than some percentage of the
 156     nursery size, reduce the TLAB size.
 157
 158  *) Explore placing unreachable objects on unused nursery memory.
 159         Instead of memset'ng a region to zero, place an int[] covering it.
 160         A good place to start is add_nursery_frag. The tricky thing here is
 161         placing those objects atomically outside of a collection.
 162
 163  *) Allocation should use asymmetric Dekker synchronization:
 164         http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
 165         This should help weak consistency archs.
 166  */
 167 #include "config.h"
 168 #ifdef HAVE_SGEN_GC
 169
 170 #ifdef __MACH__
 171 #undef _XOPEN_SOURCE
 172 #define _XOPEN_SOURCE
 173 #define _DARWIN_C_SOURCE
 174 #endif
 175
 176 #ifdef HAVE_UNISTD_H
 177 #include <unistd.h>
 178 #endif
 179 #ifdef HAVE_PTHREAD_H
 180 #include <pthread.h>
 181 #endif
 182 #ifdef HAVE_PTHREAD_NP_H
 183 #include <pthread_np.h>
 184 #endif
 185 #ifdef HAVE_SEMAPHORE_H
 186 #include <semaphore.h>
 187 #endif
 188 #include <stdio.h>
 189 #include <string.h>
 190 #include <signal.h>
 191 #include <errno.h>
 192 #include <assert.h>
 193
 194 #include "metadata/sgen-gc.h"
 195 #include "metadata/metadata-internals.h"
 196 #include "metadata/class-internals.h"
 197 #include "metadata/gc-internal.h"
 198 #include "metadata/object-internals.h"
 199 #include "metadata/threads.h"
 200 #include "metadata/sgen-cardtable.h"
 201 #include "metadata/sgen-protocol.h"
 202 #include "metadata/sgen-archdep.h"
 203 #include "metadata/sgen-bridge.h"
 204 #include "metadata/sgen-memory-governor.h"
 205 #include "metadata/sgen-hash-table.h"
 206 #include "metadata/mono-gc.h"
 207 #include "metadata/method-builder.h"
 208 #include "metadata/profiler-private.h"
 209 #include "metadata/monitor.h"
 210 #include "metadata/threadpool-internals.h"
 211 #include "metadata/mempool-internals.h"
 212 #include "metadata/marshal.h"
 213 #include "metadata/runtime.h"
 214 #include "metadata/sgen-cardtable.h"
 215 #include "metadata/sgen-pinning.h"
 216 #include "metadata/sgen-workers.h"
 217 #include "metadata/sgen-layout-stats.h"
 218 #include "utils/mono-mmap.h"
 219 #include "utils/mono-time.h"
 220 #include "utils/mono-semaphore.h"
 221 #include "utils/mono-counters.h"
 222 #include "utils/mono-proclib.h"
 223 #include "utils/mono-memory-model.h"
 224 #include "utils/mono-logger-internal.h"
 225 #include "utils/dtrace.h"
 226
 227 #include <mono/utils/mono-logger-internal.h>
 228 #include <mono/utils/memcheck.h>
 229
 230 #if defined(__MACH__)
 231 #include "utils/mach-support.h"
 232 #endif
 233
 234 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
 235         a = i,
 236
 237 enum {
 238 #include "mono/cil/opcode.def"
 239         CEE_LAST
 240 };
 241
 242 #undef OPDEF
 243
 244 #undef pthread_create
 245 #undef pthread_join
 246 #undef pthread_detach
 247
 248 /*
 249  * ######################################################################
 250  * ########  Types and constants used by the GC.
 251  * ######################################################################
 252  */
 253
 254 /* 0 means not initialized, 1 is initialized, -1 means in progress */
 255 static int gc_initialized = 0;
 256 /* If set, check if we need to do something every X allocations */
 257 gboolean has_per_allocation_action;
 258 /* If set, do a heap check every X allocation */
 259 guint32 verify_before_allocs = 0;
 260 /* If set, do a minor collection before every X allocation */
 261 guint32 collect_before_allocs = 0;
 262 /* If set, do a whole heap check before each collection */
 263 static gboolean whole_heap_check_before_collection = FALSE;
 264 /* If set, do a heap consistency check before each minor collection */
 265 static gboolean consistency_check_at_minor_collection = FALSE;
 266 /* If set, do a mod union consistency check before each finishing collection pause */
 267 static gboolean mod_union_consistency_check = FALSE;
 268 /* If set, check whether mark bits are consistent after major collections */
 269 static gboolean check_mark_bits_after_major_collection = FALSE;
 270 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
 271 static gboolean check_nursery_objects_pinned = FALSE;
 272 /* If set, do a few checks when the concurrent collector is used */
 273 static gboolean do_concurrent_checks = FALSE;
 274 /* If set, check that there are no references to the domain left at domain unload */
 275 static gboolean xdomain_checks = FALSE;
 276 /* If not null, dump the heap after each collection into this file */
 277 static FILE *heap_dump_file = NULL;
 278 /* If set, mark stacks conservatively, even if precise marking is possible */
 279 static gboolean conservative_stack_mark = FALSE;
 280 /* If set, do a plausibility check on the scan_starts before and after
 281    each collection */
 282 static gboolean do_scan_starts_check = FALSE;
 283 /*
 284  * If the major collector is concurrent and this is FALSE, we will
 285  * never initiate a synchronous major collection, unless requested via
 286  * GC.Collect().
 287  */
 288 static gboolean allow_synchronous_major = TRUE;
 289 static gboolean nursery_collection_is_parallel = FALSE;
 290 static gboolean disable_minor_collections = FALSE;
 291 static gboolean disable_major_collections = FALSE;
 292 gboolean do_pin_stats = FALSE;
 293 static gboolean do_verify_nursery = FALSE;
 294 static gboolean do_dump_nursery_content = FALSE;
 295
 296 #ifdef HEAVY_STATISTICS
 297 long long stat_objects_alloced_degraded = 0;
 298 long long stat_bytes_alloced_degraded = 0;
 299
 300 long long stat_copy_object_called_nursery = 0;
 301 long long stat_objects_copied_nursery = 0;
 302 long long stat_copy_object_called_major = 0;
 303 long long stat_objects_copied_major = 0;
 304
 305 long long stat_scan_object_called_nursery = 0;
 306 long long stat_scan_object_called_major = 0;
 307
 308 long long stat_slots_allocated_in_vain;
 309
 310 long long stat_nursery_copy_object_failed_from_space = 0;
 311 long long stat_nursery_copy_object_failed_forwarded = 0;
 312 long long stat_nursery_copy_object_failed_pinned = 0;
 313 long long stat_nursery_copy_object_failed_to_space = 0;
 314
 315 static int stat_wbarrier_add_to_global_remset = 0;
 316 static int stat_wbarrier_set_field = 0;
 317 static int stat_wbarrier_set_arrayref = 0;
 318 static int stat_wbarrier_arrayref_copy = 0;
 319 static int stat_wbarrier_generic_store = 0;
 320 static int stat_wbarrier_set_root = 0;
 321 static int stat_wbarrier_value_copy = 0;
 322 static int stat_wbarrier_object_copy = 0;
 323 #endif
 324
 325 int stat_minor_gcs = 0;
 326 int stat_major_gcs = 0;
 327
 328 static long long stat_pinned_objects = 0;
 329
 330 static long long time_minor_pre_collection_fragment_clear = 0;
 331 static long long time_minor_pinning = 0;
 332 static long long time_minor_scan_remsets = 0;
 333 static long long time_minor_scan_pinned = 0;
 334 static long long time_minor_scan_registered_roots = 0;
 335 static long long time_minor_scan_thread_data = 0;
 336 static long long time_minor_finish_gray_stack = 0;
 337 static long long time_minor_fragment_creation = 0;
 338
 339 static long long time_major_pre_collection_fragment_clear = 0;
 340 static long long time_major_pinning = 0;
 341 static long long time_major_scan_pinned = 0;
 342 static long long time_major_scan_registered_roots = 0;
 343 static long long time_major_scan_thread_data = 0;
 344 static long long time_major_scan_alloc_pinned = 0;
 345 static long long time_major_scan_finalized = 0;
 346 static long long time_major_scan_big_objects = 0;
 347 static long long time_major_finish_gray_stack = 0;
 348 static long long time_major_free_bigobjs = 0;
 349 static long long time_major_los_sweep = 0;
 350 static long long time_major_sweep = 0;
 351 static long long time_major_fragment_creation = 0;
 352
 353 int gc_debug_level = 0;
 354 FILE* gc_debug_file;
 355
 356 /*
 357 void
 358 mono_gc_flush_info (void)
 359 {
 360         fflush (gc_debug_file);
 361 }
 362 */
 363
 364 #define TV_DECLARE SGEN_TV_DECLARE
 365 #define TV_GETTIME SGEN_TV_GETTIME
 366 #define TV_ELAPSED SGEN_TV_ELAPSED
 367 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
 368
 369 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
 370
 371 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
 372
 373 #define object_is_forwarded     SGEN_OBJECT_IS_FORWARDED
 374 #define object_is_pinned        SGEN_OBJECT_IS_PINNED
 375 #define pin_object              SGEN_PIN_OBJECT
 376 #define unpin_object            SGEN_UNPIN_OBJECT
 377
 378 #define ptr_in_nursery sgen_ptr_in_nursery
 379
 380 #define LOAD_VTABLE     SGEN_LOAD_VTABLE
 381
 382 static const char*
 383 safe_name (void* obj)
 384 {
 385         MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
 386         return vt->klass->name;
 387 }
 388
 389 #define safe_object_get_size    sgen_safe_object_get_size
 390
 391 const char*
 392 sgen_safe_name (void* obj)
 393 {
 394         return safe_name (obj);
 395 }
 396
 397 /*
 398  * ######################################################################
 399  * ########  Global data.
 400  * ######################################################################
 401  */
 402 LOCK_DECLARE (gc_mutex);
 403
 404 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
 405
 406 static mword pagesize = 4096;
 407 int degraded_mode = 0;
 408
 409 static mword bytes_pinned_from_failed_allocation = 0;
 410
 411 GCMemSection *nursery_section = NULL;
 412 static mword lowest_heap_address = ~(mword)0;
 413 static mword highest_heap_address = 0;
 414
 415 LOCK_DECLARE (sgen_interruption_mutex);
 416 static LOCK_DECLARE (pin_queue_mutex);
 417
 418 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
 419 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
 420
 421 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
 422 struct _FinalizeReadyEntry {
 423         FinalizeReadyEntry *next;
 424         void *object;
 425 };
 426
 427 typedef struct _EphemeronLinkNode EphemeronLinkNode;
 428
 429 struct _EphemeronLinkNode {
 430         EphemeronLinkNode *next;
 431         char *array;
 432 };
 433
 434 typedef struct {
 435        void *key;
 436        void *value;
 437 } Ephemeron;
 438
 439 int current_collection_generation = -1;
 440 volatile gboolean concurrent_collection_in_progress = FALSE;
 441
 442 /* objects that are ready to be finalized */
 443 static FinalizeReadyEntry *fin_ready_list = NULL;
 444 static FinalizeReadyEntry *critical_fin_list = NULL;
 445
 446 static EphemeronLinkNode *ephemeron_list;
 447
 448 /* registered roots: the key to the hash is the root start address */
 449 /*
 450  * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
 451  */
 452 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
 453         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 454         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
 455         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
 456 };
 457 static mword roots_size = 0; /* amount of memory in the root set */
 458
 459 #define GC_ROOT_NUM 32
 460 typedef struct {
 461         int count;              /* must be the first field */
 462         void *objects [GC_ROOT_NUM];
 463         int root_types [GC_ROOT_NUM];
 464         uintptr_t extra_info [GC_ROOT_NUM];
 465 } GCRootReport;
 466
 467 static void
 468 notify_gc_roots (GCRootReport *report)
 469 {
 470         if (!report->count)
 471                 return;
 472         mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
 473         report->count = 0;
 474 }
 475
 476 static void
 477 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
 478 {
 479         if (report->count == GC_ROOT_NUM)
 480                 notify_gc_roots (report);
 481         report->objects [report->count] = object;
 482         report->root_types [report->count] = rtype;
 483         report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
 484 }
 485
 486 MonoNativeTlsKey thread_info_key;
 487
 488 #ifdef HAVE_KW_THREAD
 489 __thread SgenThreadInfo *sgen_thread_info;
 490 __thread char *stack_end;
 491 #endif
 492
 493 /* The size of a TLAB */
 494 /* The bigger the value, the less often we have to go to the slow path to allocate a new
 495  * one, but the more space is wasted by threads not allocating much memory.
 496  * FIXME: Tune this.
 497  * FIXME: Make this self-tuning for each thread.
 498  */
 499 guint32 tlab_size = (1024 * 4);
 500
 501 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
 502
 503 /* Functions supplied by the runtime to be called by the GC */
 504 static MonoGCCallbacks gc_callbacks;
 505
 506 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
 507 #define ALLOC_ALIGN_BITS        SGEN_ALLOC_ALIGN_BITS
 508
 509 #define ALIGN_UP                SGEN_ALIGN_UP
 510
 511 #define MOVED_OBJECTS_NUM 64
 512 static void *moved_objects [MOVED_OBJECTS_NUM];
 513 static int moved_objects_idx = 0;
 514
 515 /* Vtable of the objects used to fill out nursery fragments before a collection */
 516 static MonoVTable *array_fill_vtable;
 517
 518 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
 519 MonoNativeThreadId main_gc_thread = NULL;
 520 #endif
 521
 522 /*Object was pinned during the current collection*/
 523 static mword objects_pinned;
 524
 525 /*
 526  * ######################################################################
 527  * ########  Macros and function declarations.
 528  * ######################################################################
 529  */
 530
 531 inline static void*
 532 align_pointer (void *ptr)
 533 {
 534         mword p = (mword)ptr;
 535         p += sizeof (gpointer) - 1;
 536         p &= ~ (sizeof (gpointer) - 1);
 537         return (void*)p;
 538 }
 539
 540 typedef SgenGrayQueue GrayQueue;
 541
 542 /* forward declarations */
 543 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
 544 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
 545 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
 546 static void report_finalizer_roots (void);
 547 static void report_registered_roots (void);
 548
 549 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
 550 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
 551 static void finish_gray_stack (int generation, GrayQueue *queue);
 552
 553 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
 554
 555
 556 static void init_stats (void);
 557
 558 static int mark_ephemerons_in_range (ScanCopyContext ctx);
 559 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
 560 static void null_ephemerons_for_domain (MonoDomain *domain);
 561
 562 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
 563
 564 SgenObjectOperations current_object_ops;
 565 SgenMajorCollector major_collector;
 566 SgenMinorCollector sgen_minor_collector;
 567 static GrayQueue gray_queue;
 568
 569 static SgenRemeberedSet remset;
 570
 571 /* The gray queue to use from the main collection thread. */
 572 #define WORKERS_DISTRIBUTE_GRAY_QUEUE   (&gray_queue)
 573
 574 /*
 575  * The gray queue a worker job must use.  If we're not parallel or
 576  * concurrent, we use the main gray queue.
 577  */
 578 static SgenGrayQueue*
 579 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
 580 {
 581         return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
 582 }
 583
 584 static void
 585 gray_queue_redirect (SgenGrayQueue *queue)
 586 {
 587         gboolean wake = FALSE;
 588
 589
 590         for (;;) {
 591                 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
 592                 if (!section)
 593                         break;
 594                 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
 595                 wake = TRUE;
 596         }
 597
 598         if (wake) {
 599                 g_assert (concurrent_collection_in_progress ||
 600                                 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
 601                 if (sgen_workers_have_started ()) {
 602                         sgen_workers_wake_up_all ();
 603                 } else {
 604                         if (concurrent_collection_in_progress)
 605                                 g_assert (current_collection_generation == -1);
 606                 }
 607         }
 608 }
 609
 610 static gboolean
 611 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
 612 {
 613         MonoObject *o = (MonoObject*)(obj);
 614         MonoObject *ref = (MonoObject*)*(ptr);
 615         int offset = (char*)(ptr) - (char*)o;
 616
 617         if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
 618                 return TRUE;
 619         if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
 620                 return TRUE;
 621
 622 #ifndef DISABLE_REMOTING
 623         if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
 624                         offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
 625                 return TRUE;
 626 #endif
 627         /* Thread.cached_culture_info */
 628         if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
 629                         !strcmp (ref->vtable->klass->name, "CultureInfo") &&
 630                         !strcmp(o->vtable->klass->name_space, "System") &&
 631                         !strcmp(o->vtable->klass->name, "Object[]"))
 632                 return TRUE;
 633         /*
 634          *  at System.IO.MemoryStream.InternalConstructor (byte[],int,int,bool,bool) [0x0004d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:121
 635          * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
 636          * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
 637          * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
 638          * at System.Runtime.Remoting.Messaging.MethodCall..ctor (System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/MethodCall.cs:87
 639          * at System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) [0x00018] in /home/schani/Work/novell/trunk/mcs/class/corlib/System/AppDomain.cs:1213
 640          * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
 641          * at System.Runtime.Remoting.Channels.CrossAppDomainSink.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00008] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Channels/CrossAppDomainChannel.cs:198
 642          * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
 643          */
 644         if (!strcmp (ref->vtable->klass->name_space, "System") &&
 645                         !strcmp (ref->vtable->klass->name, "Byte[]") &&
 646                         !strcmp (o->vtable->klass->name_space, "System.IO") &&
 647                         !strcmp (o->vtable->klass->name, "MemoryStream"))
 648                 return TRUE;
 649         /* append_job() in threadpool.c */
 650         if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
 651                         !strcmp (ref->vtable->klass->name, "AsyncResult") &&
 652                         !strcmp (o->vtable->klass->name_space, "System") &&
 653                         !strcmp (o->vtable->klass->name, "Object[]") &&
 654                         mono_thread_pool_is_queue_array ((MonoArray*) o))
 655                 return TRUE;
 656         return FALSE;
 657 }
 658
 659 static void
 660 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
 661 {
 662         MonoObject *o = (MonoObject*)(obj);
 663         MonoObject *ref = (MonoObject*)*(ptr);
 664         int offset = (char*)(ptr) - (char*)o;
 665         MonoClass *class;
 666         MonoClassField *field;
 667         char *str;
 668
 669         if (!ref || ref->vtable->domain == domain)
 670                 return;
 671         if (is_xdomain_ref_allowed (ptr, obj, domain))
 672                 return;
 673
 674         field = NULL;
 675         for (class = o->vtable->klass; class; class = class->parent) {
 676                 int i;
 677
 678                 for (i = 0; i < class->field.count; ++i) {
 679                         if (class->fields[i].offset == offset) {
 680                                 field = &class->fields[i];
 681                                 break;
 682                         }
 683                 }
 684                 if (field)
 685                         break;
 686         }
 687
 688         if (ref->vtable->klass == mono_defaults.string_class)
 689                 str = mono_string_to_utf8 ((MonoString*)ref);
 690         else
 691                 str = NULL;
 692         g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s)  -  pointed to by:\n",
 693                         o, o->vtable->klass->name_space, o->vtable->klass->name,
 694                         offset, field ? field->name : "",
 695                         ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
 696         mono_gc_scan_for_specific_ref (o, TRUE);
 697         if (str)
 698                 g_free (str);
 699 }
 700
 701 #undef HANDLE_PTR
 702 #define HANDLE_PTR(ptr,obj)     check_reference_for_xdomain ((ptr), (obj), domain)
 703
 704 static void
 705 scan_object_for_xdomain_refs (char *start, mword size, void *data)
 706 {
 707         MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
 708
 709         #include "sgen-scan-object.h"
 710 }
 711
 712 static gboolean scan_object_for_specific_ref_precise = TRUE;
 713
 714 #undef HANDLE_PTR
 715 #define HANDLE_PTR(ptr,obj) do {                \
 716         if ((MonoObject*)*(ptr) == key) {       \
 717         g_print ("found ref to %p in object %p (%s) at offset %td\n",   \
 718                         key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
 719         }                                                               \
 720         } while (0)
 721
 722 static void
 723 scan_object_for_specific_ref (char *start, MonoObject *key)
 724 {
 725         char *forwarded;
 726
 727         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
 728                 start = forwarded;
 729
 730         if (scan_object_for_specific_ref_precise) {
 731                 #include "sgen-scan-object.h"
 732         } else {
 733                 mword *words = (mword*)start;
 734                 size_t size = safe_object_get_size ((MonoObject*)start);
 735                 int i;
 736                 for (i = 0; i < size / sizeof (mword); ++i) {
 737                         if (words [i] == (mword)key) {
 738                                 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
 739                                                 key, start, safe_name (start), i * sizeof (mword));
 740                         }
 741                 }
 742         }
 743 }
 744
 745 void
 746 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
 747 {
 748         while (start < end) {
 749                 size_t size;
 750                 char *obj;
 751
 752                 if (!*(void**)start) {
 753                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
 754                         continue;
 755                 }
 756
 757                 if (allow_flags) {
 758                         if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
 759                                 obj = start;
 760                 } else {
 761                         obj = start;
 762                 }
 763
 764                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
 765
 766                 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
 767                         callback (obj, size, data);
 768
 769                 start += size;
 770         }
 771 }
 772
 773 static void
 774 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
 775 {
 776         scan_object_for_specific_ref (obj, key);
 777 }
 778
 779 static void
 780 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
 781 {
 782         if (key != obj)
 783                 return;
 784         g_print ("found ref to %p in root record %p\n", key, root);
 785 }
 786
 787 static MonoObject *check_key = NULL;
 788 static RootRecord *check_root = NULL;
 789
 790 static void
 791 check_root_obj_specific_ref_from_marker (void **obj)
 792 {
 793         check_root_obj_specific_ref (check_root, check_key, *obj);
 794 }
 795
 796 static void
 797 scan_roots_for_specific_ref (MonoObject *key, int root_type)
 798 {
 799         void **start_root;
 800         RootRecord *root;
 801         check_key = key;
 802
 803         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 804                 mword desc = root->root_desc;
 805
 806                 check_root = root;
 807
 808                 switch (desc & ROOT_DESC_TYPE_MASK) {
 809                 case ROOT_DESC_BITMAP:
 810                         desc >>= ROOT_DESC_TYPE_SHIFT;
 811                         while (desc) {
 812                                 if (desc & 1)
 813                                         check_root_obj_specific_ref (root, key, *start_root);
 814                                 desc >>= 1;
 815                                 start_root++;
 816                         }
 817                         return;
 818                 case ROOT_DESC_COMPLEX: {
 819                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 820                         int bwords = (*bitmap_data) - 1;
 821                         void **start_run = start_root;
 822                         bitmap_data++;
 823                         while (bwords-- > 0) {
 824                                 gsize bmap = *bitmap_data++;
 825                                 void **objptr = start_run;
 826                                 while (bmap) {
 827                                         if (bmap & 1)
 828                                                 check_root_obj_specific_ref (root, key, *objptr);
 829                                         bmap >>= 1;
 830                                         ++objptr;
 831                                 }
 832                                 start_run += GC_BITS_PER_WORD;
 833                         }
 834                         break;
 835                 }
 836                 case ROOT_DESC_USER: {
 837                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 838                         marker (start_root, check_root_obj_specific_ref_from_marker);
 839                         break;
 840                 }
 841                 case ROOT_DESC_RUN_LEN:
 842                         g_assert_not_reached ();
 843                 default:
 844                         g_assert_not_reached ();
 845                 }
 846         } SGEN_HASH_TABLE_FOREACH_END;
 847
 848         check_key = NULL;
 849         check_root = NULL;
 850 }
 851
 852 void
 853 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
 854 {
 855         void **ptr;
 856         RootRecord *root;
 857
 858         scan_object_for_specific_ref_precise = precise;
 859
 860         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 861                         (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
 862
 863         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 864
 865         sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 866
 867         scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
 868         scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
 869
 870         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
 871                 while (ptr < (void**)root->end_root) {
 872                         check_root_obj_specific_ref (root, *ptr, key);
 873                         ++ptr;
 874                 }
 875         } SGEN_HASH_TABLE_FOREACH_END;
 876 }
 877
 878 static gboolean
 879 need_remove_object_for_domain (char *start, MonoDomain *domain)
 880 {
 881         if (mono_object_domain (start) == domain) {
 882                 SGEN_LOG (4, "Need to cleanup object %p", start);
 883                 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
 884                 return TRUE;
 885         }
 886         return FALSE;
 887 }
 888
 889 static void
 890 process_object_for_domain_clearing (char *start, MonoDomain *domain)
 891 {
 892         GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
 893         if (vt->klass == mono_defaults.internal_thread_class)
 894                 g_assert (mono_object_domain (start) == mono_get_root_domain ());
 895         /* The object could be a proxy for an object in the domain
 896            we're deleting. */
 897 #ifndef DISABLE_REMOTING
 898         if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
 899                 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
 900
 901                 /* The server could already have been zeroed out, so
 902                    we need to check for that, too. */
 903                 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
 904                         SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
 905                         ((MonoRealProxy*)start)->unwrapped_server = NULL;
 906                 }
 907         }
 908 #endif
 909 }
 910
 911 static MonoDomain *check_domain = NULL;
 912
 913 static void
 914 check_obj_not_in_domain (void **o)
 915 {
 916         g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
 917 }
 918
 919 static void
 920 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
 921 {
 922         void **start_root;
 923         RootRecord *root;
 924         check_domain = domain;
 925         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 926                 mword desc = root->root_desc;
 927
 928                 /* The MonoDomain struct is allowed to hold
 929                    references to objects in its own domain. */
 930                 if (start_root == (void**)domain)
 931                         continue;
 932
 933                 switch (desc & ROOT_DESC_TYPE_MASK) {
 934                 case ROOT_DESC_BITMAP:
 935                         desc >>= ROOT_DESC_TYPE_SHIFT;
 936                         while (desc) {
 937                                 if ((desc & 1) && *start_root)
 938                                         check_obj_not_in_domain (*start_root);
 939                                 desc >>= 1;
 940                                 start_root++;
 941                         }
 942                         break;
 943                 case ROOT_DESC_COMPLEX: {
 944                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 945                         int bwords = (*bitmap_data) - 1;
 946                         void **start_run = start_root;
 947                         bitmap_data++;
 948                         while (bwords-- > 0) {
 949                                 gsize bmap = *bitmap_data++;
 950                                 void **objptr = start_run;
 951                                 while (bmap) {
 952                                         if ((bmap & 1) && *objptr)
 953                                                 check_obj_not_in_domain (*objptr);
 954                                         bmap >>= 1;
 955                                         ++objptr;
 956                                 }
 957                                 start_run += GC_BITS_PER_WORD;
 958                         }
 959                         break;
 960                 }
 961                 case ROOT_DESC_USER: {
 962                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 963                         marker (start_root, check_obj_not_in_domain);
 964                         break;
 965                 }
 966                 case ROOT_DESC_RUN_LEN:
 967                         g_assert_not_reached ();
 968                 default:
 969                         g_assert_not_reached ();
 970                 }
 971         } SGEN_HASH_TABLE_FOREACH_END;
 972
 973         check_domain = NULL;
 974 }
 975
 976 static void
 977 check_for_xdomain_refs (void)
 978 {
 979         LOSObject *bigobj;
 980
 981         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 982                         (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
 983
 984         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
 985
 986         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
 987                 scan_object_for_xdomain_refs (bigobj->data, sgen_los_object_size (bigobj), NULL);
 988 }
 989
 990 static gboolean
 991 clear_domain_process_object (char *obj, MonoDomain *domain)
 992 {
 993         gboolean remove;
 994
 995         process_object_for_domain_clearing (obj, domain);
 996         remove = need_remove_object_for_domain (obj, domain);
 997
 998         if (remove && ((MonoObject*)obj)->synchronisation) {
 999                 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
1000                 if (dislink)
1001                         sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
1002         }
1003
1004         return remove;
1005 }
1006
1007 static void
1008 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1009 {
1010         if (clear_domain_process_object (obj, domain))
1011                 memset (obj, 0, size);
1012 }
1013
1014 static void
1015 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1016 {
1017         clear_domain_process_object (obj, domain);
1018 }
1019
1020 static void
1021 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1022 {
1023         if (need_remove_object_for_domain (obj, domain))
1024                 major_collector.free_non_pinned_object (obj, size);
1025 }
1026
1027 static void
1028 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1029 {
1030         if (need_remove_object_for_domain (obj, domain))
1031                 major_collector.free_pinned_object (obj, size);
1032 }
1033
1034 /*
1035  * When appdomains are unloaded we can easily remove objects that have finalizers,
1036  * but all the others could still be present in random places on the heap.
1037  * We need a sweep to get rid of them even though it's going to be costly
1038  * with big heaps.
1039  * The reason we need to remove them is because we access the vtable and class
1040  * structures to know the object size and the reference bitmap: once the domain is
1041  * unloaded the point to random memory.
1042  */
1043 void
1044 mono_gc_clear_domain (MonoDomain * domain)
1045 {
1046         LOSObject *bigobj, *prev;
1047         int i;
1048
1049         LOCK_GC;
1050
1051         binary_protocol_domain_unload_begin (domain);
1052
1053         sgen_stop_world (0);
1054
1055         if (concurrent_collection_in_progress)
1056                 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
1057         g_assert (!concurrent_collection_in_progress);
1058
1059         sgen_process_fin_stage_entries ();
1060         sgen_process_dislink_stage_entries ();
1061
1062         sgen_clear_nursery_fragments ();
1063
1064         if (xdomain_checks && domain != mono_get_root_domain ()) {
1065                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1066                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1067                 check_for_xdomain_refs ();
1068         }
1069
1070         /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1071         to memory returned to the OS.*/
1072         null_ephemerons_for_domain (domain);
1073
1074         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1075                 sgen_null_links_for_domain (domain, i);
1076
1077         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1078                 sgen_remove_finalizers_for_domain (domain, i);
1079
1080         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1081                         (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1082
1083         /* We need two passes over major and large objects because
1084            freeing such objects might give their memory back to the OS
1085            (in the case of large objects) or obliterate its vtable
1086            (pinned objects with major-copying or pinned and non-pinned
1087            objects with major-mark&sweep), but we might need to
1088            dereference a pointer from an object to another object if
1089            the first object is a proxy. */
1090         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1091         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1092                 clear_domain_process_object (bigobj->data, domain);
1093
1094         prev = NULL;
1095         for (bigobj = los_object_list; bigobj;) {
1096                 if (need_remove_object_for_domain (bigobj->data, domain)) {
1097                         LOSObject *to_free = bigobj;
1098                         if (prev)
1099                                 prev->next = bigobj->next;
1100                         else
1101                                 los_object_list = bigobj->next;
1102                         bigobj = bigobj->next;
1103                         SGEN_LOG (4, "Freeing large object %p", bigobj->data);
1104                         sgen_los_free_object (to_free);
1105                         continue;
1106                 }
1107                 prev = bigobj;
1108                 bigobj = bigobj->next;
1109         }
1110         major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1111         major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1112
1113         if (domain == mono_get_root_domain ()) {
1114                 if (G_UNLIKELY (do_pin_stats))
1115                         sgen_pin_stats_print_class_stats ();
1116                 sgen_object_layout_dump (stdout);
1117         }
1118
1119         sgen_restart_world (0, NULL);
1120
1121         binary_protocol_domain_unload_end (domain);
1122
1123         UNLOCK_GC;
1124 }
1125
1126 /*
1127  * sgen_add_to_global_remset:
1128  *
1129  *   The global remset contains locations which point into newspace after
1130  * a minor collection. This can happen if the objects they point to are pinned.
1131  *
1132  * LOCKING: If called from a parallel collector, the global remset
1133  * lock must be held.  For serial collectors that is not necessary.
1134  */
1135 void
1136 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
1137 {
1138         SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
1139
1140         HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
1141
1142         if (!major_collector.is_concurrent) {
1143                 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
1144         } else {
1145                 if (current_collection_generation == -1)
1146                         SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
1147         }
1148
1149         if (!object_is_pinned (obj))
1150                 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
1151         else if (sgen_cement_lookup_or_register (obj))
1152                 return;
1153
1154         remset.record_pointer (ptr);
1155
1156         if (G_UNLIKELY (do_pin_stats))
1157                 sgen_pin_stats_register_global_remset (obj);
1158
1159         SGEN_LOG (8, "Adding global remset for %p", ptr);
1160         binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
1161
1162
1163 #ifdef ENABLE_DTRACE
1164         if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
1165                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
1166                 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
1167                                 vt->klass->name_space, vt->klass->name);
1168         }
1169 #endif
1170 }
1171
1172 /*
1173  * sgen_drain_gray_stack:
1174  *
1175  *   Scan objects in the gray stack until the stack is empty. This should be called
1176  * frequently after each object is copied, to achieve better locality and cache
1177  * usage.
1178  */
1179 gboolean
1180 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
1181 {
1182         char *obj;
1183         ScanObjectFunc scan_func = ctx.scan_func;
1184         GrayQueue *queue = ctx.queue;
1185
1186         if (max_objs == -1) {
1187                 for (;;) {
1188                         GRAY_OBJECT_DEQUEUE (queue, obj);
1189                         if (!obj)
1190                                 return TRUE;
1191                         SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1192                         scan_func (obj, queue);
1193                 }
1194         } else {
1195                 int i;
1196
1197                 do {
1198                         for (i = 0; i != max_objs; ++i) {
1199                                 GRAY_OBJECT_DEQUEUE (queue, obj);
1200                                 if (!obj)
1201                                         return TRUE;
1202                                 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1203                                 scan_func (obj, queue);
1204                         }
1205                 } while (max_objs < 0);
1206                 return FALSE;
1207         }
1208 }
1209
1210 /*
1211  * Addresses from start to end are already sorted. This function finds
1212  * the object header for each address and pins the object. The
1213  * addresses must be inside the passed section.  The (start of the)
1214  * address array is overwritten with the addresses of the actually
1215  * pinned objects.  Return the number of pinned objects.
1216  */
1217 static int
1218 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1219 {
1220         void *last = NULL;
1221         int count = 0;
1222         void *search_start;
1223         void *last_obj = NULL;
1224         size_t last_obj_size = 0;
1225         void *addr;
1226         int idx;
1227         void **definitely_pinned = start;
1228         ScanObjectFunc scan_func = ctx.scan_func;
1229         SgenGrayQueue *queue = ctx.queue;
1230
1231         sgen_nursery_allocator_prepare_for_pinning ();
1232
1233         while (start < end) {
1234                 addr = *start;
1235                 /* the range check should be reduntant */
1236                 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1237                         SGEN_LOG (5, "Considering pinning addr %p", addr);
1238                         /* multiple pointers to the same object */
1239                         if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1240                                 start++;
1241                                 continue;
1242                         }
1243                         idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1244                         g_assert (idx < section->num_scan_start);
1245                         search_start = (void*)section->scan_starts [idx];
1246                         if (!search_start || search_start > addr) {
1247                                 while (idx) {
1248                                         --idx;
1249                                         search_start = section->scan_starts [idx];
1250                                         if (search_start && search_start <= addr)
1251                                                 break;
1252                                 }
1253                                 if (!search_start || search_start > addr)
1254                                         search_start = start_nursery;
1255                         }
1256                         if (search_start < last_obj)
1257                                 search_start = (char*)last_obj + last_obj_size;
1258                         /* now addr should be in an object a short distance from search_start
1259                          * Note that search_start must point to zeroed mem or point to an object.
1260                          */
1261
1262                         do {
1263                                 if (!*(void**)search_start) {
1264                                         /* Consistency check */
1265                                         /*
1266                                         for (frag = nursery_fragments; frag; frag = frag->next) {
1267                                                 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1268                                                         g_assert_not_reached ();
1269                                         }
1270                                         */
1271
1272                                         search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1273                                         continue;
1274                                 }
1275                                 last_obj = search_start;
1276                                 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1277
1278                                 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1279                                         /* Marks the beginning of a nursery fragment, skip */
1280                                 } else {
1281                                         SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
1282                                         if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1283                                                 if (scan_func) {
1284                                                         scan_func (search_start, queue);
1285                                                 } else {
1286                                                         SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1287                                                                         search_start, *(void**)search_start, safe_name (search_start), count);
1288                                                         binary_protocol_pin (search_start,
1289                                                                         (gpointer)LOAD_VTABLE (search_start),
1290                                                                         safe_object_get_size (search_start));
1291
1292 #ifdef ENABLE_DTRACE
1293                                                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1294                                                                 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
1295                                                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
1296                                                                 MONO_GC_OBJ_PINNED ((mword)search_start,
1297                                                                                 sgen_safe_object_get_size (search_start),
1298                                                                                 vt->klass->name_space, vt->klass->name, gen);
1299                                                         }
1300 #endif
1301
1302                                                         pin_object (search_start);
1303                                                         GRAY_OBJECT_ENQUEUE (queue, search_start);
1304                                                         if (G_UNLIKELY (do_pin_stats))
1305                                                                 sgen_pin_stats_register_object (search_start, last_obj_size);
1306                                                         definitely_pinned [count] = search_start;
1307                                                         count++;
1308                                                 }
1309                                                 break;
1310                                         }
1311                                 }
1312                                 /* skip to the next object */
1313                                 search_start = (void*)((char*)search_start + last_obj_size);
1314                         } while (search_start <= addr);
1315                         /* we either pinned the correct object or we ignored the addr because
1316                          * it points to unused zeroed memory.
1317                          */
1318                         last = addr;
1319                 }
1320                 start++;
1321         }
1322         //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1323         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1324                 GCRootReport report;
1325                 report.count = 0;
1326                 for (idx = 0; idx < count; ++idx)
1327                         add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1328                 notify_gc_roots (&report);
1329         }
1330         stat_pinned_objects += count;
1331         return count;
1332 }
1333
1334 void
1335 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1336 {
1337         int num_entries = section->pin_queue_num_entries;
1338         if (num_entries) {
1339                 void **start = section->pin_queue_start;
1340                 int reduced_to;
1341                 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1342                                 section->data, section->next_data, ctx);
1343                 section->pin_queue_num_entries = reduced_to;
1344                 if (!reduced_to)
1345                         section->pin_queue_start = NULL;
1346         }
1347 }
1348
1349
1350 void
1351 sgen_pin_object (void *object, GrayQueue *queue)
1352 {
1353         g_assert (!concurrent_collection_in_progress);
1354
1355         if (sgen_collection_is_parallel ()) {
1356                 LOCK_PIN_QUEUE;
1357                 /*object arrives pinned*/
1358                 sgen_pin_stage_ptr (object);
1359                 ++objects_pinned ;
1360                 UNLOCK_PIN_QUEUE;
1361         } else {
1362                 SGEN_PIN_OBJECT (object);
1363                 sgen_pin_stage_ptr (object);
1364                 ++objects_pinned;
1365                 if (G_UNLIKELY (do_pin_stats))
1366                         sgen_pin_stats_register_object (object, safe_object_get_size (object));
1367         }
1368         GRAY_OBJECT_ENQUEUE (queue, object);
1369         binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1370
1371 #ifdef ENABLE_DTRACE
1372         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1373                 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1374                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1375                 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1376         }
1377 #endif
1378 }
1379
1380 void
1381 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1382 {
1383         for (;;) {
1384                 mword vtable_word;
1385                 gboolean major_pinned = FALSE;
1386
1387                 if (sgen_ptr_in_nursery (obj)) {
1388                         if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1389                                 sgen_pin_object (obj, queue);
1390                                 break;
1391                         }
1392                 } else {
1393                         major_collector.pin_major_object (obj, queue);
1394                         major_pinned = TRUE;
1395                 }
1396
1397                 vtable_word = *(mword*)obj;
1398                 /*someone else forwarded it, update the pointer and bail out*/
1399                 if (vtable_word & SGEN_FORWARDED_BIT) {
1400                         *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1401                         break;
1402                 }
1403
1404                 /*someone pinned it, nothing to do.*/
1405                 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1406                         break;
1407         }
1408 }
1409
1410 /* Sort the addresses in array in increasing order.
1411  * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1412  */
1413 void
1414 sgen_sort_addresses (void **array, int size)
1415 {
1416         int i;
1417         void *tmp;
1418
1419         for (i = 1; i < size; ++i) {
1420                 int child = i;
1421                 while (child > 0) {
1422                         int parent = (child - 1) / 2;
1423
1424                         if (array [parent] >= array [child])
1425                                 break;
1426
1427                         tmp = array [parent];
1428                         array [parent] = array [child];
1429                         array [child] = tmp;
1430
1431                         child = parent;
1432                 }
1433         }
1434
1435         for (i = size - 1; i > 0; --i) {
1436                 int end, root;
1437                 tmp = array [i];
1438                 array [i] = array [0];
1439                 array [0] = tmp;
1440
1441                 end = i - 1;
1442                 root = 0;
1443
1444                 while (root * 2 + 1 <= end) {
1445                         int child = root * 2 + 1;
1446
1447                         if (child < end && array [child] < array [child + 1])
1448                                 ++child;
1449                         if (array [root] >= array [child])
1450                                 break;
1451
1452                         tmp = array [root];
1453                         array [root] = array [child];
1454                         array [child] = tmp;
1455
1456                         root = child;
1457                 }
1458         }
1459 }
1460
1461 /*
1462  * Scan the memory between start and end and queue values which could be pointers
1463  * to the area between start_nursery and end_nursery for later consideration.
1464  * Typically used for thread stacks.
1465  */
1466 static void
1467 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1468 {
1469         int count = 0;
1470
1471 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1472         VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1473 #endif
1474
1475         while (start < end) {
1476                 if (*start >= start_nursery && *start < end_nursery) {
1477                         /*
1478                          * *start can point to the middle of an object
1479                          * note: should we handle pointing at the end of an object?
1480                          * pinning in C# code disallows pointing at the end of an object
1481                          * but there is some small chance that an optimizing C compiler
1482                          * may keep the only reference to an object by pointing
1483                          * at the end of it. We ignore this small chance for now.
1484                          * Pointers to the end of an object are indistinguishable
1485                          * from pointers to the start of the next object in memory
1486                          * so if we allow that we'd need to pin two objects...
1487                          * We queue the pointer in an array, the
1488                          * array will then be sorted and uniqued. This way
1489                          * we can coalesce several pinning pointers and it should
1490                          * be faster since we'd do a memory scan with increasing
1491                          * addresses. Note: we can align the address to the allocation
1492                          * alignment, so the unique process is more effective.
1493                          */
1494                         mword addr = (mword)*start;
1495                         addr &= ~(ALLOC_ALIGN - 1);
1496                         if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1497                                 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1498                                 sgen_pin_stage_ptr ((void*)addr);
1499                                 count++;
1500                         }
1501                         if (G_UNLIKELY (do_pin_stats)) {
1502                                 if (ptr_in_nursery ((void*)addr))
1503                                         sgen_pin_stats_register_address ((char*)addr, pin_type);
1504                         }
1505                 }
1506                 start++;
1507         }
1508         if (count)
1509                 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1510 }
1511
1512 /*
1513  * The first thing we do in a collection is to identify pinned objects.
1514  * This function considers all the areas of memory that need to be
1515  * conservatively scanned.
1516  */
1517 static void
1518 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1519 {
1520         void **start_root;
1521         RootRecord *root;
1522         SGEN_LOG (2, "Scanning pinned roots (%d bytes, %d/%d entries)", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries);
1523         /* objects pinned from the API are inside these roots */
1524         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1525                 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1526                 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1527         } SGEN_HASH_TABLE_FOREACH_END;
1528         /* now deal with the thread stacks
1529          * in the future we should be able to conservatively scan only:
1530          * *) the cpu registers
1531          * *) the unmanaged stack frames
1532          * *) the _last_ managed stack frame
1533          * *) pointers slots in managed frames
1534          */
1535         scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1536 }
1537
1538 static void
1539 unpin_objects_from_queue (SgenGrayQueue *queue)
1540 {
1541         for (;;) {
1542                 char *addr;
1543                 GRAY_OBJECT_DEQUEUE (queue, addr);
1544                 if (!addr)
1545                         break;
1546                 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1547                 SGEN_UNPIN_OBJECT (addr);
1548         }
1549 }
1550
1551 typedef struct {
1552         CopyOrMarkObjectFunc func;
1553         GrayQueue *queue;
1554 } UserCopyOrMarkData;
1555
1556 static MonoNativeTlsKey user_copy_or_mark_key;
1557
1558 static void
1559 init_user_copy_or_mark_key (void)
1560 {
1561         mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1562 }
1563
1564 static void
1565 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1566 {
1567         mono_native_tls_set_value (user_copy_or_mark_key, data);
1568 }
1569
1570 static void
1571 single_arg_user_copy_or_mark (void **obj)
1572 {
1573         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1574
1575         data->func (obj, data->queue);
1576 }
1577
1578 /*
1579  * The memory area from start_root to end_root contains pointers to objects.
1580  * Their position is precisely described by @desc (this means that the pointer
1581  * can be either NULL or the pointer to the start of an object).
1582  * This functions copies them to to_space updates them.
1583  *
1584  * This function is not thread-safe!
1585  */
1586 static void
1587 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1588 {
1589         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1590         SgenGrayQueue *queue = ctx.queue;
1591
1592         switch (desc & ROOT_DESC_TYPE_MASK) {
1593         case ROOT_DESC_BITMAP:
1594                 desc >>= ROOT_DESC_TYPE_SHIFT;
1595                 while (desc) {
1596                         if ((desc & 1) && *start_root) {
1597                                 copy_func (start_root, queue);
1598                                 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1599                                 sgen_drain_gray_stack (-1, ctx);
1600                         }
1601                         desc >>= 1;
1602                         start_root++;
1603                 }
1604                 return;
1605         case ROOT_DESC_COMPLEX: {
1606                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1607                 int bwords = (*bitmap_data) - 1;
1608                 void **start_run = start_root;
1609                 bitmap_data++;
1610                 while (bwords-- > 0) {
1611                         gsize bmap = *bitmap_data++;
1612                         void **objptr = start_run;
1613                         while (bmap) {
1614                                 if ((bmap & 1) && *objptr) {
1615                                         copy_func (objptr, queue);
1616                                         SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1617                                         sgen_drain_gray_stack (-1, ctx);
1618                                 }
1619                                 bmap >>= 1;
1620                                 ++objptr;
1621                         }
1622                         start_run += GC_BITS_PER_WORD;
1623                 }
1624                 break;
1625         }
1626         case ROOT_DESC_USER: {
1627                 UserCopyOrMarkData data = { copy_func, queue };
1628                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1629                 set_user_copy_or_mark_data (&data);
1630                 marker (start_root, single_arg_user_copy_or_mark);
1631                 set_user_copy_or_mark_data (NULL);
1632                 break;
1633         }
1634         case ROOT_DESC_RUN_LEN:
1635                 g_assert_not_reached ();
1636         default:
1637                 g_assert_not_reached ();
1638         }
1639 }
1640
1641 static void
1642 reset_heap_boundaries (void)
1643 {
1644         lowest_heap_address = ~(mword)0;
1645         highest_heap_address = 0;
1646 }
1647
1648 void
1649 sgen_update_heap_boundaries (mword low, mword high)
1650 {
1651         mword old;
1652
1653         do {
1654                 old = lowest_heap_address;
1655                 if (low >= old)
1656                         break;
1657         } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1658
1659         do {
1660                 old = highest_heap_address;
1661                 if (high <= old)
1662                         break;
1663         } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1664 }
1665
1666 /*
1667  * Allocate and setup the data structures needed to be able to allocate objects
1668  * in the nursery. The nursery is stored in nursery_section.
1669  */
1670 static void
1671 alloc_nursery (void)
1672 {
1673         GCMemSection *section;
1674         char *data;
1675         int scan_starts;
1676         int alloc_size;
1677
1678         if (nursery_section)
1679                 return;
1680         SGEN_LOG (2, "Allocating nursery size: %lu", (unsigned long)sgen_nursery_size);
1681         /* later we will alloc a larger area for the nursery but only activate
1682          * what we need. The rest will be used as expansion if we have too many pinned
1683          * objects in the existing nursery.
1684          */
1685         /* FIXME: handle OOM */
1686         section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1687
1688         alloc_size = sgen_nursery_size;
1689
1690         /* If there isn't enough space even for the nursery we should simply abort. */
1691         g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1692
1693 #ifdef SGEN_ALIGN_NURSERY
1694         data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1695 #else
1696         data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1697 #endif
1698         sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1699         SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)mono_gc_get_heap_size ());
1700         section->data = section->next_data = data;
1701         section->size = alloc_size;
1702         section->end_data = data + sgen_nursery_size;
1703         scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1704         section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1705         section->num_scan_start = scan_starts;
1706
1707         nursery_section = section;
1708
1709         sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1710 }
1711
1712 void*
1713 mono_gc_get_nursery (int *shift_bits, size_t *size)
1714 {
1715         *size = sgen_nursery_size;
1716 #ifdef SGEN_ALIGN_NURSERY
1717         *shift_bits = DEFAULT_NURSERY_BITS;
1718 #else
1719         *shift_bits = -1;
1720 #endif
1721         return sgen_get_nursery_start ();
1722 }
1723
1724 void
1725 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1726 {
1727         SgenThreadInfo *info = mono_thread_info_current ();
1728
1729         /* Could be called from sgen_thread_unregister () with a NULL info */
1730         if (domain) {
1731                 g_assert (info);
1732                 info->stopped_domain = domain;
1733         }
1734 }
1735
1736 gboolean
1737 mono_gc_precise_stack_mark_enabled (void)
1738 {
1739         return !conservative_stack_mark;
1740 }
1741
1742 FILE *
1743 mono_gc_get_logfile (void)
1744 {
1745         return gc_debug_file;
1746 }
1747
1748 static void
1749 report_finalizer_roots_list (FinalizeReadyEntry *list)
1750 {
1751         GCRootReport report;
1752         FinalizeReadyEntry *fin;
1753
1754         report.count = 0;
1755         for (fin = list; fin; fin = fin->next) {
1756                 if (!fin->object)
1757                         continue;
1758                 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1759         }
1760         notify_gc_roots (&report);
1761 }
1762
1763 static void
1764 report_finalizer_roots (void)
1765 {
1766         report_finalizer_roots_list (fin_ready_list);
1767         report_finalizer_roots_list (critical_fin_list);
1768 }
1769
1770 static GCRootReport *root_report;
1771
1772 static void
1773 single_arg_report_root (void **obj)
1774 {
1775         if (*obj)
1776                 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1777 }
1778
1779 static void
1780 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1781 {
1782         switch (desc & ROOT_DESC_TYPE_MASK) {
1783         case ROOT_DESC_BITMAP:
1784                 desc >>= ROOT_DESC_TYPE_SHIFT;
1785                 while (desc) {
1786                         if ((desc & 1) && *start_root) {
1787                                 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1788                         }
1789                         desc >>= 1;
1790                         start_root++;
1791                 }
1792                 return;
1793         case ROOT_DESC_COMPLEX: {
1794                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1795                 int bwords = (*bitmap_data) - 1;
1796                 void **start_run = start_root;
1797                 bitmap_data++;
1798                 while (bwords-- > 0) {
1799                         gsize bmap = *bitmap_data++;
1800                         void **objptr = start_run;
1801                         while (bmap) {
1802                                 if ((bmap & 1) && *objptr) {
1803                                         add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1804                                 }
1805                                 bmap >>= 1;
1806                                 ++objptr;
1807                         }
1808                         start_run += GC_BITS_PER_WORD;
1809                 }
1810                 break;
1811         }
1812         case ROOT_DESC_USER: {
1813                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1814                 root_report = report;
1815                 marker (start_root, single_arg_report_root);
1816                 break;
1817         }
1818         case ROOT_DESC_RUN_LEN:
1819                 g_assert_not_reached ();
1820         default:
1821                 g_assert_not_reached ();
1822         }
1823 }
1824
1825 static void
1826 report_registered_roots_by_type (int root_type)
1827 {
1828         GCRootReport report;
1829         void **start_root;
1830         RootRecord *root;
1831         report.count = 0;
1832         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1833                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1834                 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1835         } SGEN_HASH_TABLE_FOREACH_END;
1836         notify_gc_roots (&report);
1837 }
1838
1839 static void
1840 report_registered_roots (void)
1841 {
1842         report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1843         report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1844 }
1845
1846 static void
1847 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1848 {
1849         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1850         SgenGrayQueue *queue = ctx.queue;
1851         FinalizeReadyEntry *fin;
1852
1853         for (fin = list; fin; fin = fin->next) {
1854                 if (!fin->object)
1855                         continue;
1856                 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1857                 copy_func (&fin->object, queue);
1858         }
1859 }
1860
1861 static const char*
1862 generation_name (int generation)
1863 {
1864         switch (generation) {
1865         case GENERATION_NURSERY: return "nursery";
1866         case GENERATION_OLD: return "old";
1867         default: g_assert_not_reached ();
1868         }
1869 }
1870
1871 const char*
1872 sgen_generation_name (int generation)
1873 {
1874         return generation_name (generation);
1875 }
1876
1877 SgenObjectOperations *
1878 sgen_get_current_object_ops (void){
1879         return &current_object_ops;
1880 }
1881
1882
1883 static void
1884 finish_gray_stack (int generation, GrayQueue *queue)
1885 {
1886         TV_DECLARE (atv);
1887         TV_DECLARE (btv);
1888         int done_with_ephemerons, ephemeron_rounds = 0;
1889         CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1890         ScanObjectFunc scan_func = current_object_ops.scan_object;
1891         ScanCopyContext ctx = { scan_func, copy_func, queue };
1892         char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1893         char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1894
1895         /*
1896          * We copied all the reachable objects. Now it's the time to copy
1897          * the objects that were not referenced by the roots, but by the copied objects.
1898          * we built a stack of objects pointed to by gray_start: they are
1899          * additional roots and we may add more items as we go.
1900          * We loop until gray_start == gray_objects which means no more objects have
1901          * been added. Note this is iterative: no recursion is involved.
1902          * We need to walk the LO list as well in search of marked big objects
1903          * (use a flag since this is needed only on major collections). We need to loop
1904          * here as well, so keep a counter of marked LO (increasing it in copy_object).
1905          *   To achieve better cache locality and cache usage, we drain the gray stack
1906          * frequently, after each object is copied, and just finish the work here.
1907          */
1908         sgen_drain_gray_stack (-1, ctx);
1909         TV_GETTIME (atv);
1910         SGEN_LOG (2, "%s generation done", generation_name (generation));
1911
1912         /*
1913         Reset bridge data, we might have lingering data from a previous collection if this is a major
1914         collection trigged by minor overflow.
1915
1916         We must reset the gathered bridges since their original block might be evacuated due to major
1917         fragmentation in the meanwhile and the bridge code should not have to deal with that.
1918         */
1919         sgen_bridge_reset_data ();
1920
1921         /*
1922          * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1923          * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1924          * objects that are in fact reachable.
1925          */
1926         done_with_ephemerons = 0;
1927         do {
1928                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1929                 sgen_drain_gray_stack (-1, ctx);
1930                 ++ephemeron_rounds;
1931         } while (!done_with_ephemerons);
1932
1933         sgen_scan_togglerefs (start_addr, end_addr, ctx);
1934
1935         if (sgen_need_bridge_processing ()) {
1936                 sgen_collect_bridge_objects (generation, ctx);
1937                 if (generation == GENERATION_OLD)
1938                         sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1939         }
1940
1941         /*
1942         Make sure we drain the gray stack before processing disappearing links and finalizers.
1943         If we don't make sure it is empty we might wrongly see a live object as dead.
1944         */
1945         sgen_drain_gray_stack (-1, ctx);
1946
1947         /*
1948         We must clear weak links that don't track resurrection before processing object ready for
1949         finalization so they can be cleared before that.
1950         */
1951         sgen_null_link_in_range (generation, TRUE, ctx);
1952         if (generation == GENERATION_OLD)
1953                 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1954
1955
1956         /* walk the finalization queue and move also the objects that need to be
1957          * finalized: use the finalized objects as new roots so the objects they depend
1958          * on are also not reclaimed. As with the roots above, only objects in the nursery
1959          * are marked/copied.
1960          */
1961         sgen_finalize_in_range (generation, ctx);
1962         if (generation == GENERATION_OLD)
1963                 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1964         /* drain the new stack that might have been created */
1965         SGEN_LOG (6, "Precise scan of gray area post fin");
1966         sgen_drain_gray_stack (-1, ctx);
1967
1968         /*
1969          * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1970          */
1971         done_with_ephemerons = 0;
1972         do {
1973                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1974                 sgen_drain_gray_stack (-1, ctx);
1975                 ++ephemeron_rounds;
1976         } while (!done_with_ephemerons);
1977
1978         /*
1979          * Clear ephemeron pairs with unreachable keys.
1980          * We pass the copy func so we can figure out if an array was promoted or not.
1981          */
1982         clear_unreachable_ephemerons (ctx);
1983
1984         TV_GETTIME (btv);
1985         SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1986
1987         /*
1988          * handle disappearing links
1989          * Note we do this after checking the finalization queue because if an object
1990          * survives (at least long enough to be finalized) we don't clear the link.
1991          * This also deals with a possible issue with the monitor reclamation: with the Boehm
1992          * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1993          * called.
1994          */
1995         g_assert (sgen_gray_object_queue_is_empty (queue));
1996         for (;;) {
1997                 sgen_null_link_in_range (generation, FALSE, ctx);
1998                 if (generation == GENERATION_OLD)
1999                         sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
2000                 if (sgen_gray_object_queue_is_empty (queue))
2001                         break;
2002                 sgen_drain_gray_stack (-1, ctx);
2003         }
2004
2005         g_assert (sgen_gray_object_queue_is_empty (queue));
2006 }
2007
2008 void
2009 sgen_check_section_scan_starts (GCMemSection *section)
2010 {
2011         int i;
2012         for (i = 0; i < section->num_scan_start; ++i) {
2013                 if (section->scan_starts [i]) {
2014                         guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2015                         g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2016                 }
2017         }
2018 }
2019
2020 static void
2021 check_scan_starts (void)
2022 {
2023         if (!do_scan_starts_check)
2024                 return;
2025         sgen_check_section_scan_starts (nursery_section);
2026         major_collector.check_scan_starts ();
2027 }
2028
2029 static void
2030 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
2031 {
2032         void **start_root;
2033         RootRecord *root;
2034         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2035                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
2036                 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
2037         } SGEN_HASH_TABLE_FOREACH_END;
2038 }
2039
2040 void
2041 sgen_dump_occupied (char *start, char *end, char *section_start)
2042 {
2043         fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2044 }
2045
2046 void
2047 sgen_dump_section (GCMemSection *section, const char *type)
2048 {
2049         char *start = section->data;
2050         char *end = section->data + section->size;
2051         char *occ_start = NULL;
2052         GCVTable *vt;
2053         char *old_start = NULL; /* just for debugging */
2054
2055         fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2056
2057         while (start < end) {
2058                 guint size;
2059                 MonoClass *class;
2060
2061                 if (!*(void**)start) {
2062                         if (occ_start) {
2063                                 sgen_dump_occupied (occ_start, start, section->data);
2064                                 occ_start = NULL;
2065                         }
2066                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2067                         continue;
2068                 }
2069                 g_assert (start < section->next_data);
2070
2071                 if (!occ_start)
2072                         occ_start = start;
2073
2074                 vt = (GCVTable*)LOAD_VTABLE (start);
2075                 class = vt->klass;
2076
2077                 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2078
2079                 /*
2080                 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2081                                 start - section->data,
2082                                 vt->klass->name_space, vt->klass->name,
2083                                 size);
2084                 */
2085
2086                 old_start = start;
2087                 start += size;
2088         }
2089         if (occ_start)
2090                 sgen_dump_occupied (occ_start, start, section->data);
2091
2092         fprintf (heap_dump_file, "</section>\n");
2093 }
2094
2095 static void
2096 dump_object (MonoObject *obj, gboolean dump_location)
2097 {
2098         static char class_name [1024];
2099
2100         MonoClass *class = mono_object_class (obj);
2101         int i, j;
2102
2103         /*
2104          * Python's XML parser is too stupid to parse angle brackets
2105          * in strings, so we just ignore them;
2106          */
2107         i = j = 0;
2108         while (class->name [i] && j < sizeof (class_name) - 1) {
2109                 if (!strchr ("<>\"", class->name [i]))
2110                         class_name [j++] = class->name [i];
2111                 ++i;
2112         }
2113         g_assert (j < sizeof (class_name));
2114         class_name [j] = 0;
2115
2116         fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2117                         class->name_space, class_name,
2118                         safe_object_get_size (obj));
2119         if (dump_location) {
2120                 const char *location;
2121                 if (ptr_in_nursery (obj))
2122                         location = "nursery";
2123                 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2124                         location = "major";
2125                 else
2126                         location = "LOS";
2127                 fprintf (heap_dump_file, " location=\"%s\"", location);
2128         }
2129         fprintf (heap_dump_file, "/>\n");
2130 }
2131
2132 static void
2133 dump_heap (const char *type, int num, const char *reason)
2134 {
2135         ObjectList *list;
2136         LOSObject *bigobj;
2137
2138         fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2139         if (reason)
2140                 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2141         fprintf (heap_dump_file, ">\n");
2142         fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2143         sgen_dump_internal_mem_usage (heap_dump_file);
2144         fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2145         /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2146         fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2147
2148         fprintf (heap_dump_file, "<pinned-objects>\n");
2149         for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2150                 dump_object (list->obj, TRUE);
2151         fprintf (heap_dump_file, "</pinned-objects>\n");
2152
2153         sgen_dump_section (nursery_section, "nursery");
2154
2155         major_collector.dump_heap (heap_dump_file);
2156
2157         fprintf (heap_dump_file, "<los>\n");
2158         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2159                 dump_object ((MonoObject*)bigobj->data, FALSE);
2160         fprintf (heap_dump_file, "</los>\n");
2161
2162         fprintf (heap_dump_file, "</collection>\n");
2163 }
2164
2165 void
2166 sgen_register_moved_object (void *obj, void *destination)
2167 {
2168         g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2169
2170         /* FIXME: handle this for parallel collector */
2171         g_assert (!sgen_collection_is_parallel ());
2172
2173         if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2174                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2175                 moved_objects_idx = 0;
2176         }
2177         moved_objects [moved_objects_idx++] = obj;
2178         moved_objects [moved_objects_idx++] = destination;
2179 }
2180
2181 static void
2182 init_stats (void)
2183 {
2184         static gboolean inited = FALSE;
2185
2186         if (inited)
2187                 return;
2188
2189         mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2190         mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2191         mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2192         mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2193         mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2194         mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2195         mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2196         mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2197
2198         mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2199         mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2200         mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2201         mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2202         mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2203         mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2204         mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2205         mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2206         mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2207         mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2208         mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2209         mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2210         mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2211
2212         mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2213
2214 #ifdef HEAVY_STATISTICS
2215         mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
2216         mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2217         mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2218         mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2219         mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2220         mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2221         mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2222         mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2223
2224         mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2225         mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2226
2227         mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2228         mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2229         mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2230         mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2231
2232         mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2233         mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2234
2235         mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2236
2237         mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2238         mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2239         mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2240         mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2241
2242         sgen_nursery_allocator_init_heavy_stats ();
2243         sgen_alloc_init_heavy_stats ();
2244 #endif
2245
2246         inited = TRUE;
2247 }
2248
2249
2250 static void
2251 reset_pinned_from_failed_allocation (void)
2252 {
2253         bytes_pinned_from_failed_allocation = 0;
2254 }
2255
2256 void
2257 sgen_set_pinned_from_failed_allocation (mword objsize)
2258 {
2259         bytes_pinned_from_failed_allocation += objsize;
2260 }
2261
2262 gboolean
2263 sgen_collection_is_parallel (void)
2264 {
2265         switch (current_collection_generation) {
2266         case GENERATION_NURSERY:
2267                 return nursery_collection_is_parallel;
2268         case GENERATION_OLD:
2269                 return major_collector.is_parallel;
2270         default:
2271                 g_error ("Invalid current generation %d", current_collection_generation);
2272         }
2273 }
2274
2275 gboolean
2276 sgen_collection_is_concurrent (void)
2277 {
2278         switch (current_collection_generation) {
2279         case GENERATION_NURSERY:
2280                 return FALSE;
2281         case GENERATION_OLD:
2282                 return concurrent_collection_in_progress;
2283         default:
2284                 g_error ("Invalid current generation %d", current_collection_generation);
2285         }
2286 }
2287
2288 gboolean
2289 sgen_concurrent_collection_in_progress (void)
2290 {
2291         return concurrent_collection_in_progress;
2292 }
2293
2294 typedef struct
2295 {
2296         char *heap_start;
2297         char *heap_end;
2298 } FinishRememberedSetScanJobData;
2299
2300 static void
2301 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2302 {
2303         FinishRememberedSetScanJobData *job_data = job_data_untyped;
2304
2305         remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2306         sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2307 }
2308
2309 typedef struct
2310 {
2311         CopyOrMarkObjectFunc copy_or_mark_func;
2312         ScanObjectFunc scan_func;
2313         char *heap_start;
2314         char *heap_end;
2315         int root_type;
2316 } ScanFromRegisteredRootsJobData;
2317
2318 static void
2319 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2320 {
2321         ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2322         ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2323                 sgen_workers_get_job_gray_queue (worker_data) };
2324
2325         scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2326         sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2327 }
2328
2329 typedef struct
2330 {
2331         char *heap_start;
2332         char *heap_end;
2333 } ScanThreadDataJobData;
2334
2335 static void
2336 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2337 {
2338         ScanThreadDataJobData *job_data = job_data_untyped;
2339
2340         scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2341                         sgen_workers_get_job_gray_queue (worker_data));
2342         sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2343 }
2344
2345 typedef struct
2346 {
2347         FinalizeReadyEntry *list;
2348 } ScanFinalizerEntriesJobData;
2349
2350 static void
2351 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2352 {
2353         ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2354         ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2355
2356         scan_finalizer_entries (job_data->list, ctx);
2357         sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2358 }
2359
2360 static void
2361 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2362 {
2363         g_assert (concurrent_collection_in_progress);
2364         major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2365 }
2366
2367 static void
2368 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2369 {
2370         g_assert (concurrent_collection_in_progress);
2371         sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2372 }
2373
2374 static void
2375 verify_scan_starts (char *start, char *end)
2376 {
2377         int i;
2378
2379         for (i = 0; i < nursery_section->num_scan_start; ++i) {
2380                 char *addr = nursery_section->scan_starts [i];
2381                 if (addr > start && addr < end)
2382                         SGEN_LOG (1, "NFC-BAD SCAN START [%d] %p for obj [%p %p]", i, addr, start, end);
2383         }
2384 }
2385
2386 static void
2387 verify_nursery (void)
2388 {
2389         char *start, *end, *cur, *hole_start;
2390
2391         if (!do_verify_nursery)
2392                 return;
2393
2394         /*This cleans up unused fragments */
2395         sgen_nursery_allocator_prepare_for_pinning ();
2396
2397         hole_start = start = cur = sgen_get_nursery_start ();
2398         end = sgen_get_nursery_end ();
2399
2400         while (cur < end) {
2401                 size_t ss, size;
2402
2403                 if (!*(void**)cur) {
2404                         cur += sizeof (void*);
2405                         continue;
2406                 }
2407
2408                 if (object_is_forwarded (cur))
2409                         SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2410                 else if (object_is_pinned (cur))
2411                         SGEN_LOG (1, "PINNED OBJ %p", cur);
2412
2413                 ss = safe_object_get_size ((MonoObject*)cur);
2414                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2415                 verify_scan_starts (cur, cur + size);
2416                 if (do_dump_nursery_content) {
2417                         if (cur > hole_start)
2418                                 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2419                         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 ());
2420                 }
2421                 cur += size;
2422                 hole_start = cur;
2423         }
2424 }
2425
2426 /*
2427  * Checks that no objects in the nursery are fowarded or pinned.  This
2428  * is a precondition to restarting the mutator while doing a
2429  * concurrent collection.  Note that we don't clear fragments because
2430  * we depend on that having happened earlier.
2431  */
2432 static void
2433 check_nursery_is_clean (void)
2434 {
2435         char *start, *end, *cur;
2436
2437         start = cur = sgen_get_nursery_start ();
2438         end = sgen_get_nursery_end ();
2439
2440         while (cur < end) {
2441                 size_t ss, size;
2442
2443                 if (!*(void**)cur) {
2444                         cur += sizeof (void*);
2445                         continue;
2446                 }
2447
2448                 g_assert (!object_is_forwarded (cur));
2449                 g_assert (!object_is_pinned (cur));
2450
2451                 ss = safe_object_get_size ((MonoObject*)cur);
2452                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2453                 verify_scan_starts (cur, cur + size);
2454
2455                 cur += size;
2456         }
2457 }
2458
2459 static void
2460 init_gray_queue (void)
2461 {
2462         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2463                 sgen_workers_init_distribute_gray_queue ();
2464                 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2465                                 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2466         } else {
2467                 sgen_gray_object_queue_init (&gray_queue, NULL);
2468         }
2469 }
2470
2471 static void
2472 pin_stage_object_callback (char *obj, size_t size, void *data)
2473 {
2474         sgen_pin_stage_ptr (obj);
2475         /* FIXME: do pin stats if enabled */
2476 }
2477
2478 /*
2479  * Collect objects in the nursery.  Returns whether to trigger a major
2480  * collection.
2481  */
2482 static gboolean
2483 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2484 {
2485         gboolean needs_major;
2486         size_t max_garbage_amount;
2487         char *nursery_next;
2488         FinishRememberedSetScanJobData *frssjd;
2489         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2490         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2491         ScanThreadDataJobData *stdjd;
2492         mword fragment_total;
2493         ScanCopyContext ctx;
2494         TV_DECLARE (all_atv);
2495         TV_DECLARE (all_btv);
2496         TV_DECLARE (atv);
2497         TV_DECLARE (btv);
2498
2499         if (disable_minor_collections)
2500                 return TRUE;
2501
2502         MONO_GC_BEGIN (GENERATION_NURSERY);
2503         binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2504
2505         verify_nursery ();
2506
2507 #ifndef DISABLE_PERFCOUNTERS
2508         mono_perfcounters->gc_collections0++;
2509 #endif
2510
2511         current_collection_generation = GENERATION_NURSERY;
2512         if (sgen_collection_is_parallel ())
2513                 current_object_ops = sgen_minor_collector.parallel_ops;
2514         else
2515                 current_object_ops = sgen_minor_collector.serial_ops;
2516
2517         reset_pinned_from_failed_allocation ();
2518
2519         check_scan_starts ();
2520
2521         sgen_nursery_alloc_prepare_for_minor ();
2522
2523         degraded_mode = 0;
2524         objects_pinned = 0;
2525         nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2526         /* FIXME: optimize later to use the higher address where an object can be present */
2527         nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2528
2529         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 ()));
2530         max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2531         g_assert (nursery_section->size >= max_garbage_amount);
2532
2533         /* world must be stopped already */
2534         TV_GETTIME (all_atv);
2535         atv = all_atv;
2536
2537         TV_GETTIME (btv);
2538         time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2539
2540         if (xdomain_checks) {
2541                 sgen_clear_nursery_fragments ();
2542                 check_for_xdomain_refs ();
2543         }
2544
2545         nursery_section->next_data = nursery_next;
2546
2547         major_collector.start_nursery_collection ();
2548
2549         sgen_memgov_minor_collection_start ();
2550
2551         init_gray_queue ();
2552
2553         stat_minor_gcs++;
2554         gc_stats.minor_gc_count ++;
2555
2556         MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2557
2558         sgen_process_fin_stage_entries ();
2559         sgen_process_dislink_stage_entries ();
2560
2561         MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2562
2563         /* pin from pinned handles */
2564         sgen_init_pinning ();
2565         mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2566         pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2567         /* pin cemented objects */
2568         sgen_cement_iterate (pin_stage_object_callback, NULL);
2569         /* identify pinned objects */
2570         sgen_optimize_pin_queue (0);
2571         sgen_pinning_setup_section (nursery_section);
2572         ctx.scan_func = NULL;
2573         ctx.copy_func = NULL;
2574         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2575         sgen_pin_objects_in_section (nursery_section, ctx);
2576         sgen_pinning_trim_queue_to_section (nursery_section);
2577
2578         TV_GETTIME (atv);
2579         time_minor_pinning += TV_ELAPSED (btv, atv);
2580         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2581         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2582
2583         MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2584
2585         if (whole_heap_check_before_collection) {
2586                 sgen_clear_nursery_fragments ();
2587                 sgen_check_whole_heap (finish_up_concurrent_mark);
2588         }
2589         if (consistency_check_at_minor_collection)
2590                 sgen_check_consistency ();
2591
2592         sgen_workers_start_all_workers ();
2593         sgen_workers_start_marking ();
2594
2595         frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2596         frssjd->heap_start = sgen_get_nursery_start ();
2597         frssjd->heap_end = nursery_next;
2598         sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2599
2600         /* we don't have complete write barrier yet, so we scan all the old generation sections */
2601         TV_GETTIME (btv);
2602         time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2603         SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2604
2605         MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2606
2607         if (!sgen_collection_is_parallel ()) {
2608                 ctx.scan_func = current_object_ops.scan_object;
2609                 ctx.copy_func = NULL;
2610                 ctx.queue = &gray_queue;
2611                 sgen_drain_gray_stack (-1, ctx);
2612         }
2613
2614         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2615                 report_registered_roots ();
2616         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2617                 report_finalizer_roots ();
2618         TV_GETTIME (atv);
2619         time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2620
2621         MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2622
2623         /* registered roots, this includes static fields */
2624         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2625         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2626         scrrjd_normal->scan_func = current_object_ops.scan_object;
2627         scrrjd_normal->heap_start = sgen_get_nursery_start ();
2628         scrrjd_normal->heap_end = nursery_next;
2629         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2630         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2631
2632         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2633         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2634         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2635         scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2636         scrrjd_wbarrier->heap_end = nursery_next;
2637         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2638         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2639
2640         TV_GETTIME (btv);
2641         time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2642
2643         MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2644
2645         /* thread data */
2646         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2647         stdjd->heap_start = sgen_get_nursery_start ();
2648         stdjd->heap_end = nursery_next;
2649         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2650
2651         TV_GETTIME (atv);
2652         time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2653         btv = atv;
2654
2655         MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2656
2657         g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2658
2659         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2660                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2661
2662         /* Scan the list of objects ready for finalization. If */
2663         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2664         sfejd_fin_ready->list = fin_ready_list;
2665         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2666
2667         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2668         sfejd_critical_fin->list = critical_fin_list;
2669         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2670
2671         MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2672
2673         finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2674         TV_GETTIME (atv);
2675         time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2676         mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2677
2678         MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2679
2680         /*
2681          * The (single-threaded) finalization code might have done
2682          * some copying/marking so we can only reset the GC thread's
2683          * worker data here instead of earlier when we joined the
2684          * workers.
2685          */
2686         sgen_workers_reset_data ();
2687
2688         if (objects_pinned) {
2689                 sgen_optimize_pin_queue (0);
2690                 sgen_pinning_setup_section (nursery_section);
2691         }
2692
2693         /* walk the pin_queue, build up the fragment list of free memory, unmark
2694          * pinned objects as we go, memzero() the empty fragments so they are ready for the
2695          * next allocations.
2696          */
2697         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2698         fragment_total = sgen_build_nursery_fragments (nursery_section,
2699                         nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2700                         unpin_queue);
2701         if (!fragment_total)
2702                 degraded_mode = 1;
2703
2704         /* Clear TLABs for all threads */
2705         sgen_clear_tlabs ();
2706
2707         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2708         TV_GETTIME (btv);
2709         time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2710         SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2711
2712         if (consistency_check_at_minor_collection)
2713                 sgen_check_major_refs ();
2714
2715         major_collector.finish_nursery_collection ();
2716
2717         TV_GETTIME (all_btv);
2718         gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2719
2720         if (heap_dump_file)
2721                 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2722
2723         /* prepare the pin queue for the next collection */
2724         sgen_finish_pinning ();
2725         if (fin_ready_list || critical_fin_list) {
2726                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2727                 mono_gc_finalize_notify ();
2728         }
2729         sgen_pin_stats_reset ();
2730         /* clear cemented hash */
2731         sgen_cement_clear_below_threshold ();
2732
2733         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2734
2735         remset.finish_minor_collection ();
2736
2737         check_scan_starts ();
2738
2739         binary_protocol_flush_buffers (FALSE);
2740
2741         sgen_memgov_minor_collection_end ();
2742
2743         /*objects are late pinned because of lack of memory, so a major is a good call*/
2744         needs_major = objects_pinned > 0;
2745         current_collection_generation = -1;
2746         objects_pinned = 0;
2747
2748         MONO_GC_END (GENERATION_NURSERY);
2749         binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2750
2751         if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2752                 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2753
2754         return needs_major;
2755 }
2756
2757 static void
2758 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2759 {
2760         ctx->scan_func (obj, ctx->queue);
2761 }
2762
2763 static void
2764 scan_nursery_objects (ScanCopyContext ctx)
2765 {
2766         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2767                         (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2768 }
2769
2770 static void
2771 major_copy_or_mark_from_roots (int *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2772 {
2773         LOSObject *bigobj;
2774         TV_DECLARE (atv);
2775         TV_DECLARE (btv);
2776         /* FIXME: only use these values for the precise scan
2777          * note that to_space pointers should be excluded anyway...
2778          */
2779         char *heap_start = NULL;
2780         char *heap_end = (char*)-1;
2781         gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2782         GCRootReport root_report = { 0 };
2783         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2784         ScanThreadDataJobData *stdjd;
2785         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2786         ScanCopyContext ctx;
2787
2788         if (concurrent_collection_in_progress) {
2789                 /*This cleans up unused fragments */
2790                 sgen_nursery_allocator_prepare_for_pinning ();
2791
2792                 if (do_concurrent_checks)
2793                         check_nursery_is_clean ();
2794         } else {
2795                 /* The concurrent collector doesn't touch the nursery. */
2796                 sgen_nursery_alloc_prepare_for_major ();
2797         }
2798
2799         init_gray_queue ();
2800
2801         TV_GETTIME (atv);
2802
2803         /* Pinning depends on this */
2804         sgen_clear_nursery_fragments ();
2805
2806         if (whole_heap_check_before_collection)
2807                 sgen_check_whole_heap (finish_up_concurrent_mark);
2808
2809         TV_GETTIME (btv);
2810         time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2811
2812         if (!sgen_collection_is_concurrent ())
2813                 nursery_section->next_data = sgen_get_nursery_end ();
2814         /* we should also coalesce scanning from sections close to each other
2815          * and deal with pointers outside of the sections later.
2816          */
2817
2818         objects_pinned = 0;
2819         *major_collector.have_swept = FALSE;
2820
2821         if (xdomain_checks) {
2822                 sgen_clear_nursery_fragments ();
2823                 check_for_xdomain_refs ();
2824         }
2825
2826         if (!concurrent_collection_in_progress) {
2827                 /* Remsets are not useful for a major collection */
2828                 remset.prepare_for_major_collection ();
2829         }
2830
2831         sgen_process_fin_stage_entries ();
2832         sgen_process_dislink_stage_entries ();
2833
2834         TV_GETTIME (atv);
2835         sgen_init_pinning ();
2836         SGEN_LOG (6, "Collecting pinned addresses");
2837         pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2838
2839         if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2840                 if (major_collector.is_concurrent) {
2841                         /*
2842                          * The concurrent major collector cannot evict
2843                          * yet, so we need to pin cemented objects to
2844                          * not break some asserts.
2845                          *
2846                          * FIXME: We could evict now!
2847                          */
2848                         sgen_cement_iterate (pin_stage_object_callback, NULL);
2849                 }
2850
2851                 if (!concurrent_collection_in_progress)
2852                         sgen_cement_reset ();
2853         }
2854
2855         sgen_optimize_pin_queue (0);
2856
2857         /*
2858          * The concurrent collector doesn't move objects, neither on
2859          * the major heap nor in the nursery, so we can mark even
2860          * before pinning has finished.  For the non-concurrent
2861          * collector we start the workers after pinning.
2862          */
2863         if (concurrent_collection_in_progress) {
2864                 sgen_workers_start_all_workers ();
2865                 sgen_workers_start_marking ();
2866         }
2867
2868         /*
2869          * pin_queue now contains all candidate pointers, sorted and
2870          * uniqued.  We must do two passes now to figure out which
2871          * objects are pinned.
2872          *
2873          * The first is to find within the pin_queue the area for each
2874          * section.  This requires that the pin_queue be sorted.  We
2875          * also process the LOS objects and pinned chunks here.
2876          *
2877          * The second, destructive, pass is to reduce the section
2878          * areas to pointers to the actually pinned objects.
2879          */
2880         SGEN_LOG (6, "Pinning from sections");
2881         /* first pass for the sections */
2882         sgen_find_section_pin_queue_start_end (nursery_section);
2883         major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2884         /* identify possible pointers to the insize of large objects */
2885         SGEN_LOG (6, "Pinning from large objects");
2886         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2887                 int dummy;
2888                 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2889                         binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2890
2891 #ifdef ENABLE_DTRACE
2892                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2893                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2894                                 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2895                         }
2896 #endif
2897
2898                         if (sgen_los_object_is_pinned (bigobj->data)) {
2899                                 g_assert (finish_up_concurrent_mark);
2900                                 continue;
2901                         }
2902                         sgen_los_pin_object (bigobj->data);
2903                         /* FIXME: only enqueue if object has references */
2904                         GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2905                         if (G_UNLIKELY (do_pin_stats))
2906                                 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2907                         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));
2908
2909                         if (profile_roots)
2910                                 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2911                 }
2912         }
2913         if (profile_roots)
2914                 notify_gc_roots (&root_report);
2915         /* second pass for the sections */
2916         ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2917         ctx.copy_func = NULL;
2918         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2919
2920         /*
2921          * Concurrent mark never follows references into the nursery.
2922          * In the start and finish pauses we must scan live nursery
2923          * objects, though.  We could simply scan all nursery objects,
2924          * but that would be conservative.  The easiest way is to do a
2925          * nursery collection, which copies all live nursery objects
2926          * (except pinned ones, with the simple nursery) to the major
2927          * heap.  Scanning the mod union table later will then scan
2928          * those promoted objects, provided they're reachable.  Pinned
2929          * objects in the nursery - which we can trivially find in the
2930          * pinning queue - are treated as roots in the mark pauses.
2931          *
2932          * The split nursery complicates the latter part because
2933          * non-pinned objects can survive in the nursery.  That's why
2934          * we need to do a full front-to-back scan of the nursery,
2935          * marking all objects.
2936          *
2937          * Non-concurrent mark evacuates from the nursery, so it's
2938          * sufficient to just scan pinned nursery objects.
2939          */
2940         if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2941                 scan_nursery_objects (ctx);
2942         } else {
2943                 sgen_pin_objects_in_section (nursery_section, ctx);
2944                 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2945                         sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2946         }
2947
2948         major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2949         if (old_next_pin_slot)
2950                 *old_next_pin_slot = sgen_get_pinned_count ();
2951
2952         TV_GETTIME (btv);
2953         time_major_pinning += TV_ELAPSED (atv, btv);
2954         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2955         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2956
2957         major_collector.init_to_space ();
2958
2959 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2960         main_gc_thread = mono_native_thread_self ();
2961 #endif
2962
2963         if (!concurrent_collection_in_progress && major_collector.is_parallel) {
2964                 sgen_workers_start_all_workers ();
2965                 sgen_workers_start_marking ();
2966         }
2967
2968         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2969                 report_registered_roots ();
2970         TV_GETTIME (atv);
2971         time_major_scan_pinned += TV_ELAPSED (btv, atv);
2972
2973         /* registered roots, this includes static fields */
2974         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2975         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2976         scrrjd_normal->scan_func = current_object_ops.scan_object;
2977         scrrjd_normal->heap_start = heap_start;
2978         scrrjd_normal->heap_end = heap_end;
2979         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2980         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2981
2982         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2983         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2984         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2985         scrrjd_wbarrier->heap_start = heap_start;
2986         scrrjd_wbarrier->heap_end = heap_end;
2987         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2988         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2989
2990         TV_GETTIME (btv);
2991         time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2992
2993         /* Threads */
2994         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2995         stdjd->heap_start = heap_start;
2996         stdjd->heap_end = heap_end;
2997         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2998
2999         TV_GETTIME (atv);
3000         time_major_scan_thread_data += TV_ELAPSED (btv, atv);
3001
3002         TV_GETTIME (btv);
3003         time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
3004
3005         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
3006                 report_finalizer_roots ();
3007
3008         /* scan the list of objects ready for finalization */
3009         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3010         sfejd_fin_ready->list = fin_ready_list;
3011         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
3012
3013         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3014         sfejd_critical_fin->list = critical_fin_list;
3015         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
3016
3017         if (scan_mod_union) {
3018                 g_assert (finish_up_concurrent_mark);
3019
3020                 /* Mod union card table */
3021                 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
3022                 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
3023         }
3024
3025         TV_GETTIME (atv);
3026         time_major_scan_finalized += TV_ELAPSED (btv, atv);
3027         SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
3028
3029         TV_GETTIME (btv);
3030         time_major_scan_big_objects += TV_ELAPSED (atv, btv);
3031
3032         if (concurrent_collection_in_progress) {
3033                 /* prepare the pin queue for the next collection */
3034                 sgen_finish_pinning ();
3035
3036                 sgen_pin_stats_reset ();
3037
3038                 if (do_concurrent_checks)
3039                         check_nursery_is_clean ();
3040         }
3041 }
3042
3043 static void
3044 major_start_collection (gboolean concurrent, int *old_next_pin_slot)
3045 {
3046         MONO_GC_BEGIN (GENERATION_OLD);
3047         binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
3048
3049         current_collection_generation = GENERATION_OLD;
3050 #ifndef DISABLE_PERFCOUNTERS
3051         mono_perfcounters->gc_collections1++;
3052 #endif
3053
3054         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3055
3056         if (concurrent) {
3057                 g_assert (major_collector.is_concurrent);
3058                 concurrent_collection_in_progress = TRUE;
3059
3060                 sgen_cement_concurrent_start ();
3061
3062                 current_object_ops = major_collector.major_concurrent_ops;
3063         } else {
3064                 current_object_ops = major_collector.major_ops;
3065         }
3066
3067         reset_pinned_from_failed_allocation ();
3068
3069         sgen_memgov_major_collection_start ();
3070
3071         //count_ref_nonref_objs ();
3072         //consistency_check ();
3073
3074         check_scan_starts ();
3075
3076         degraded_mode = 0;
3077         SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
3078         stat_major_gcs++;
3079         gc_stats.major_gc_count ++;
3080
3081         if (major_collector.start_major_collection)
3082                 major_collector.start_major_collection ();
3083
3084         major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
3085 }
3086
3087 static void
3088 wait_for_workers_to_finish (void)
3089 {
3090         if (concurrent_collection_in_progress || major_collector.is_parallel) {
3091                 gray_queue_redirect (&gray_queue);
3092                 sgen_workers_join ();
3093         }
3094
3095         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3096
3097 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3098         main_gc_thread = NULL;
3099 #endif
3100 }
3101
3102 static void
3103 major_finish_collection (const char *reason, int old_next_pin_slot, gboolean scan_mod_union)
3104 {
3105         LOSObject *bigobj, *prevbo;
3106         TV_DECLARE (atv);
3107         TV_DECLARE (btv);
3108
3109         TV_GETTIME (btv);
3110
3111         if (concurrent_collection_in_progress || major_collector.is_parallel)
3112                 wait_for_workers_to_finish ();
3113
3114         if (concurrent_collection_in_progress) {
3115                 current_object_ops = major_collector.major_concurrent_ops;
3116
3117                 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
3118                 wait_for_workers_to_finish ();
3119
3120                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3121
3122                 if (do_concurrent_checks)
3123                         check_nursery_is_clean ();
3124         } else {
3125                 current_object_ops = major_collector.major_ops;
3126         }
3127
3128         /*
3129          * The workers have stopped so we need to finish gray queue
3130          * work that might result from finalization in the main GC
3131          * thread.  Redirection must therefore be turned off.
3132          */
3133         sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
3134         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3135
3136         /* all the objects in the heap */
3137         finish_gray_stack (GENERATION_OLD, &gray_queue);
3138         TV_GETTIME (atv);
3139         time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3140
3141         /*
3142          * The (single-threaded) finalization code might have done
3143          * some copying/marking so we can only reset the GC thread's
3144          * worker data here instead of earlier when we joined the
3145          * workers.
3146          */
3147         sgen_workers_reset_data ();
3148
3149         if (objects_pinned) {
3150                 g_assert (!concurrent_collection_in_progress);
3151
3152                 /*This is slow, but we just OOM'd*/
3153                 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3154                 sgen_optimize_pin_queue (0);
3155                 sgen_find_section_pin_queue_start_end (nursery_section);
3156                 objects_pinned = 0;
3157         }
3158
3159         reset_heap_boundaries ();
3160         sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3161
3162         if (check_mark_bits_after_major_collection)
3163                 sgen_check_major_heap_marked ();
3164
3165         MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
3166
3167         /* sweep the big objects list */
3168         prevbo = NULL;
3169         for (bigobj = los_object_list; bigobj;) {
3170                 g_assert (!object_is_pinned (bigobj->data));
3171                 if (sgen_los_object_is_pinned (bigobj->data)) {
3172                         sgen_los_unpin_object (bigobj->data);
3173                         sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
3174                 } else {
3175                         LOSObject *to_free;
3176                         /* not referenced anywhere, so we can free it */
3177                         if (prevbo)
3178                                 prevbo->next = bigobj->next;
3179                         else
3180                                 los_object_list = bigobj->next;
3181                         to_free = bigobj;
3182                         bigobj = bigobj->next;
3183                         sgen_los_free_object (to_free);
3184                         continue;
3185                 }
3186                 prevbo = bigobj;
3187                 bigobj = bigobj->next;
3188         }
3189
3190         TV_GETTIME (btv);
3191         time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3192
3193         sgen_los_sweep ();
3194
3195         TV_GETTIME (atv);
3196         time_major_los_sweep += TV_ELAPSED (btv, atv);
3197
3198         major_collector.sweep ();
3199
3200         MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
3201
3202         TV_GETTIME (btv);
3203         time_major_sweep += TV_ELAPSED (atv, btv);
3204
3205         if (!concurrent_collection_in_progress) {
3206                 /* walk the pin_queue, build up the fragment list of free memory, unmark
3207                  * pinned objects as we go, memzero() the empty fragments so they are ready for the
3208                  * next allocations.
3209                  */
3210                 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
3211                         degraded_mode = 1;
3212
3213                 /* prepare the pin queue for the next collection */
3214                 sgen_finish_pinning ();
3215
3216                 /* Clear TLABs for all threads */
3217                 sgen_clear_tlabs ();
3218
3219                 sgen_pin_stats_reset ();
3220         }
3221
3222         if (concurrent_collection_in_progress)
3223                 sgen_cement_concurrent_finish ();
3224         sgen_cement_clear_below_threshold ();
3225
3226         TV_GETTIME (atv);
3227         time_major_fragment_creation += TV_ELAPSED (btv, atv);
3228
3229         if (heap_dump_file)
3230                 dump_heap ("major", stat_major_gcs - 1, reason);
3231
3232         if (fin_ready_list || critical_fin_list) {
3233                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
3234                 mono_gc_finalize_notify ();
3235         }
3236
3237         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3238
3239         sgen_memgov_major_collection_end ();
3240         current_collection_generation = -1;
3241
3242         major_collector.finish_major_collection ();
3243
3244         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3245
3246         if (concurrent_collection_in_progress)
3247                 concurrent_collection_in_progress = FALSE;
3248
3249         check_scan_starts ();
3250
3251         binary_protocol_flush_buffers (FALSE);
3252
3253         //consistency_check ();
3254
3255         MONO_GC_END (GENERATION_OLD);
3256         binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
3257 }
3258
3259 static gboolean
3260 major_do_collection (const char *reason)
3261 {
3262         TV_DECLARE (all_atv);
3263         TV_DECLARE (all_btv);
3264         int old_next_pin_slot;
3265
3266         if (disable_major_collections)
3267                 return FALSE;
3268
3269         if (major_collector.get_and_reset_num_major_objects_marked) {
3270                 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3271                 g_assert (!num_marked);
3272         }
3273
3274         /* world must be stopped already */
3275         TV_GETTIME (all_atv);
3276
3277         major_start_collection (FALSE, &old_next_pin_slot);
3278         major_finish_collection (reason, old_next_pin_slot, FALSE);
3279
3280         TV_GETTIME (all_btv);
3281         gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3282
3283         /* FIXME: also report this to the user, preferably in gc-end. */
3284         if (major_collector.get_and_reset_num_major_objects_marked)
3285                 major_collector.get_and_reset_num_major_objects_marked ();
3286
3287         return bytes_pinned_from_failed_allocation > 0;
3288 }
3289
3290 static void
3291 major_start_concurrent_collection (const char *reason)
3292 {
3293         long long num_objects_marked;
3294
3295         if (disable_major_collections)
3296                 return;
3297
3298         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3299         g_assert (num_objects_marked == 0);
3300
3301         MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3302
3303         // FIXME: store reason and pass it when finishing
3304         major_start_collection (TRUE, NULL);
3305
3306         gray_queue_redirect (&gray_queue);
3307         sgen_workers_wait_for_jobs ();
3308
3309         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3310         MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3311
3312         current_collection_generation = -1;
3313 }
3314
3315 static gboolean
3316 major_update_or_finish_concurrent_collection (gboolean force_finish)
3317 {
3318         SgenGrayQueue unpin_queue;
3319         memset (&unpin_queue, 0, sizeof (unpin_queue));
3320
3321         MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3322
3323         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3324
3325         major_collector.update_cardtable_mod_union ();
3326         sgen_los_update_cardtable_mod_union ();
3327
3328         if (!force_finish && !sgen_workers_all_done ()) {
3329                 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3330                 return FALSE;
3331         }
3332
3333         if (mod_union_consistency_check)
3334                 sgen_check_mod_union_consistency ();
3335
3336         collect_nursery (&unpin_queue, TRUE);
3337
3338         current_collection_generation = GENERATION_OLD;
3339         major_finish_collection ("finishing", -1, TRUE);
3340
3341         if (whole_heap_check_before_collection)
3342                 sgen_check_whole_heap (FALSE);
3343
3344         unpin_objects_from_queue (&unpin_queue);
3345         sgen_gray_object_queue_deinit (&unpin_queue);
3346
3347         MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3348
3349         current_collection_generation = -1;
3350
3351         return TRUE;
3352 }
3353
3354 /*
3355  * Ensure an allocation request for @size will succeed by freeing enough memory.
3356  *
3357  * LOCKING: The GC lock MUST be held.
3358  */
3359 void
3360 sgen_ensure_free_space (size_t size)
3361 {
3362         int generation_to_collect = -1;
3363         const char *reason = NULL;
3364
3365
3366         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3367                 if (sgen_need_major_collection (size)) {
3368                         reason = "LOS overflow";
3369                         generation_to_collect = GENERATION_OLD;
3370                 }
3371         } else {
3372                 if (degraded_mode) {
3373                         if (sgen_need_major_collection (size)) {
3374                                 reason = "Degraded mode overflow";
3375                                 generation_to_collect = GENERATION_OLD;
3376                         }
3377                 } else if (sgen_need_major_collection (size)) {
3378                         reason = "Minor allowance";
3379                         generation_to_collect = GENERATION_OLD;
3380                 } else {
3381                         generation_to_collect = GENERATION_NURSERY;
3382                         reason = "Nursery full";
3383                 }
3384         }
3385
3386         if (generation_to_collect == -1) {
3387                 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3388                         generation_to_collect = GENERATION_OLD;
3389                         reason = "Finish concurrent collection";
3390                 }
3391         }
3392
3393         if (generation_to_collect == -1)
3394                 return;
3395         sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3396 }
3397
3398 /*
3399  * LOCKING: Assumes the GC lock is held.
3400  */
3401 void
3402 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3403 {
3404         TV_DECLARE (gc_end);
3405         GGTimingInfo infos [2];
3406         int overflow_generation_to_collect = -1;
3407         int oldest_generation_collected = generation_to_collect;
3408         const char *overflow_reason = NULL;
3409
3410         MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3411         if (wait_to_finish)
3412                 binary_protocol_collection_force (generation_to_collect);
3413
3414         g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3415
3416         memset (infos, 0, sizeof (infos));
3417         mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3418
3419         infos [0].generation = generation_to_collect;
3420         infos [0].reason = reason;
3421         infos [0].is_overflow = FALSE;
3422         TV_GETTIME (infos [0].total_time);
3423         infos [1].generation = -1;
3424
3425         sgen_stop_world (generation_to_collect);
3426
3427         if (concurrent_collection_in_progress) {
3428                 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3429                         oldest_generation_collected = GENERATION_OLD;
3430                         goto done;
3431                 }
3432                 if (generation_to_collect == GENERATION_OLD)
3433                         goto done;
3434         } else {
3435                 if (generation_to_collect == GENERATION_OLD &&
3436                                 allow_synchronous_major &&
3437                                 major_collector.want_synchronous_collection &&
3438                                 *major_collector.want_synchronous_collection) {
3439                         wait_to_finish = TRUE;
3440                 }
3441         }
3442
3443         //FIXME extract overflow reason
3444         if (generation_to_collect == GENERATION_NURSERY) {
3445                 if (collect_nursery (NULL, FALSE)) {
3446                         overflow_generation_to_collect = GENERATION_OLD;
3447                         overflow_reason = "Minor overflow";
3448                 }
3449         } else {
3450                 if (major_collector.is_concurrent) {
3451                         g_assert (!concurrent_collection_in_progress);
3452                         if (!wait_to_finish)
3453                                 collect_nursery (NULL, FALSE);
3454                 }
3455
3456                 if (major_collector.is_concurrent && !wait_to_finish) {
3457                         major_start_concurrent_collection (reason);
3458                         // FIXME: set infos[0] properly
3459                         goto done;
3460                 } else {
3461                         if (major_do_collection (reason)) {
3462                                 overflow_generation_to_collect = GENERATION_NURSERY;
3463                                 overflow_reason = "Excessive pinning";
3464                         }
3465                 }
3466         }
3467
3468         TV_GETTIME (gc_end);
3469         infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3470
3471
3472         if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3473                 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3474                 infos [1].generation = overflow_generation_to_collect;
3475                 infos [1].reason = overflow_reason;
3476                 infos [1].is_overflow = TRUE;
3477                 infos [1].total_time = gc_end;
3478
3479                 if (overflow_generation_to_collect == GENERATION_NURSERY)
3480                         collect_nursery (NULL, FALSE);
3481                 else
3482                         major_do_collection (overflow_reason);
3483
3484                 TV_GETTIME (gc_end);
3485                 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3486
3487                 /* keep events symmetric */
3488                 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3489
3490                 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3491         }
3492
3493         SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3494
3495         /* this also sets the proper pointers for the next allocation */
3496         if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3497                 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3498                 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3499                 sgen_dump_pin_queue ();
3500                 degraded_mode = 1;
3501         }
3502
3503  done:
3504         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3505
3506         sgen_restart_world (oldest_generation_collected, infos);
3507
3508         mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3509 }
3510
3511 /*
3512  * ######################################################################
3513  * ########  Memory allocation from the OS
3514  * ######################################################################
3515  * This section of code deals with getting memory from the OS and
3516  * allocating memory for GC-internal data structures.
3517  * Internal memory can be handled with a freelist for small objects.
3518  */
3519
3520 /*
3521  * Debug reporting.
3522  */
3523 G_GNUC_UNUSED static void
3524 report_internal_mem_usage (void)
3525 {
3526         printf ("Internal memory usage:\n");
3527         sgen_report_internal_mem_usage ();
3528         printf ("Pinned memory usage:\n");
3529         major_collector.report_pinned_memory_usage ();
3530 }
3531
3532 /*
3533  * ######################################################################
3534  * ########  Finalization support
3535  * ######################################################################
3536  */
3537
3538 static inline gboolean
3539 sgen_major_is_object_alive (void *object)
3540 {
3541         mword objsize;
3542
3543         /* Oldgen objects can be pinned and forwarded too */
3544         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3545                 return TRUE;
3546
3547         /*
3548          * FIXME: major_collector.is_object_live() also calculates the
3549          * size.  Avoid the double calculation.
3550          */
3551         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3552         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3553                 return sgen_los_object_is_pinned (object);
3554
3555         return major_collector.is_object_live (object);
3556 }
3557
3558 /*
3559  * If the object has been forwarded it means it's still referenced from a root.
3560  * If it is pinned it's still alive as well.
3561  * A LOS object is only alive if we have pinned it.
3562  * Return TRUE if @obj is ready to be finalized.
3563  */
3564 static inline gboolean
3565 sgen_is_object_alive (void *object)
3566 {
3567         if (ptr_in_nursery (object))
3568                 return sgen_nursery_is_object_alive (object);
3569
3570         return sgen_major_is_object_alive (object);
3571 }
3572
3573 /*
3574  * This function returns true if @object is either alive or it belongs to the old gen
3575  * and we're currently doing a minor collection.
3576  */
3577 static inline int
3578 sgen_is_object_alive_for_current_gen (char *object)
3579 {
3580         if (ptr_in_nursery (object))
3581                 return sgen_nursery_is_object_alive (object);
3582
3583         if (current_collection_generation == GENERATION_NURSERY)
3584                 return TRUE;
3585
3586         return sgen_major_is_object_alive (object);
3587 }
3588
3589 /*
3590  * This function returns true if @object is either alive and belongs to the
3591  * current collection - major collections are full heap, so old gen objects
3592  * are never alive during a minor collection.
3593  */
3594 static inline int
3595 sgen_is_object_alive_and_on_current_collection (char *object)
3596 {
3597         if (ptr_in_nursery (object))
3598                 return sgen_nursery_is_object_alive (object);
3599
3600         if (current_collection_generation == GENERATION_NURSERY)
3601                 return FALSE;
3602
3603         return sgen_major_is_object_alive (object);
3604 }
3605
3606
3607 gboolean
3608 sgen_gc_is_object_ready_for_finalization (void *object)
3609 {
3610         return !sgen_is_object_alive (object);
3611 }
3612
3613 static gboolean
3614 has_critical_finalizer (MonoObject *obj)
3615 {
3616         MonoClass *class;
3617
3618         if (!mono_defaults.critical_finalizer_object)
3619                 return FALSE;
3620
3621         class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3622
3623         return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3624 }
3625
3626 void
3627 sgen_queue_finalization_entry (MonoObject *obj)
3628 {
3629         FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3630         gboolean critical = has_critical_finalizer (obj);
3631         entry->object = obj;
3632         if (critical) {
3633                 entry->next = critical_fin_list;
3634                 critical_fin_list = entry;
3635         } else {
3636                 entry->next = fin_ready_list;
3637                 fin_ready_list = entry;
3638         }
3639
3640 #ifdef ENABLE_DTRACE
3641         if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3642                 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3643                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3644                 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3645                                 vt->klass->name_space, vt->klass->name, gen, critical);
3646         }
3647 #endif
3648 }
3649
3650 gboolean
3651 sgen_object_is_live (void *obj)
3652 {
3653         return sgen_is_object_alive_and_on_current_collection (obj);
3654 }
3655
3656 /* LOCKING: requires that the GC lock is held */
3657 static void
3658 null_ephemerons_for_domain (MonoDomain *domain)
3659 {
3660         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3661
3662         while (current) {
3663                 MonoObject *object = (MonoObject*)current->array;
3664
3665                 if (object && !object->vtable) {
3666                         EphemeronLinkNode *tmp = current;
3667
3668                         if (prev)
3669                                 prev->next = current->next;
3670                         else
3671                                 ephemeron_list = current->next;
3672
3673                         current = current->next;
3674                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3675                 } else {
3676                         prev = current;
3677                         current = current->next;
3678                 }
3679         }
3680 }
3681
3682 /* LOCKING: requires that the GC lock is held */
3683 static void
3684 clear_unreachable_ephemerons (ScanCopyContext ctx)
3685 {
3686         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3687         GrayQueue *queue = ctx.queue;
3688         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3689         MonoArray *array;
3690         Ephemeron *cur, *array_end;
3691         char *tombstone;
3692
3693         while (current) {
3694                 char *object = current->array;
3695
3696                 if (!sgen_is_object_alive_for_current_gen (object)) {
3697                         EphemeronLinkNode *tmp = current;
3698
3699                         SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3700
3701                         if (prev)
3702                                 prev->next = current->next;
3703                         else
3704                                 ephemeron_list = current->next;
3705
3706                         current = current->next;
3707                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3708
3709                         continue;
3710                 }
3711
3712                 copy_func ((void**)&object, queue);
3713                 current->array = object;
3714
3715                 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3716
3717                 array = (MonoArray*)object;
3718                 cur = mono_array_addr (array, Ephemeron, 0);
3719                 array_end = cur + mono_array_length_fast (array);
3720                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3721
3722                 for (; cur < array_end; ++cur) {
3723                         char *key = (char*)cur->key;
3724
3725                         if (!key || key == tombstone)
3726                                 continue;
3727
3728                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3729                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3730                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3731
3732                         if (!sgen_is_object_alive_for_current_gen (key)) {
3733                                 cur->key = tombstone;
3734                                 cur->value = NULL;
3735                                 continue;
3736                         }
3737                 }
3738                 prev = current;
3739                 current = current->next;
3740         }
3741 }
3742
3743 /*
3744 LOCKING: requires that the GC lock is held
3745
3746 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3747 */
3748 static int
3749 mark_ephemerons_in_range (ScanCopyContext ctx)
3750 {
3751         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3752         GrayQueue *queue = ctx.queue;
3753         int nothing_marked = 1;
3754         EphemeronLinkNode *current = ephemeron_list;
3755         MonoArray *array;
3756         Ephemeron *cur, *array_end;
3757         char *tombstone;
3758
3759         for (current = ephemeron_list; current; current = current->next) {
3760                 char *object = current->array;
3761                 SGEN_LOG (5, "Ephemeron array at %p", object);
3762
3763                 /*It has to be alive*/
3764                 if (!sgen_is_object_alive_for_current_gen (object)) {
3765                         SGEN_LOG (5, "\tnot reachable");
3766                         continue;
3767                 }
3768
3769                 copy_func ((void**)&object, queue);
3770
3771                 array = (MonoArray*)object;
3772                 cur = mono_array_addr (array, Ephemeron, 0);
3773                 array_end = cur + mono_array_length_fast (array);
3774                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3775
3776                 for (; cur < array_end; ++cur) {
3777                         char *key = cur->key;
3778
3779                         if (!key || key == tombstone)
3780                                 continue;
3781
3782                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3783                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3784                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3785
3786                         if (sgen_is_object_alive_for_current_gen (key)) {
3787                                 char *value = cur->value;
3788
3789                                 copy_func ((void**)&cur->key, queue);
3790                                 if (value) {
3791                                         if (!sgen_is_object_alive_for_current_gen (value))
3792                                                 nothing_marked = 0;
3793                                         copy_func ((void**)&cur->value, queue);
3794                                 }
3795                         }
3796                 }
3797         }
3798
3799         SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3800         return nothing_marked;
3801 }
3802
3803 int
3804 mono_gc_invoke_finalizers (void)
3805 {
3806         FinalizeReadyEntry *entry = NULL;
3807         gboolean entry_is_critical = FALSE;
3808         int count = 0;
3809         void *obj;
3810         /* FIXME: batch to reduce lock contention */
3811         while (fin_ready_list || critical_fin_list) {
3812                 LOCK_GC;
3813
3814                 if (entry) {
3815                         FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3816
3817                         /* We have finalized entry in the last
3818                            interation, now we need to remove it from
3819                            the list. */
3820                         if (*list == entry)
3821                                 *list = entry->next;
3822                         else {
3823                                 FinalizeReadyEntry *e = *list;
3824                                 while (e->next != entry)
3825                                         e = e->next;
3826                                 e->next = entry->next;
3827                         }
3828                         sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3829                         entry = NULL;
3830                 }
3831
3832                 /* Now look for the first non-null entry. */
3833                 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3834                         ;
3835                 if (entry) {
3836                         entry_is_critical = FALSE;
3837                 } else {
3838                         entry_is_critical = TRUE;
3839                         for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3840                                 ;
3841                 }
3842
3843                 if (entry) {
3844                         g_assert (entry->object);
3845                         num_ready_finalizers--;
3846                         obj = entry->object;
3847                         entry->object = NULL;
3848                         SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3849                 }
3850
3851                 UNLOCK_GC;
3852
3853                 if (!entry)
3854                         break;
3855
3856                 g_assert (entry->object == NULL);
3857                 count++;
3858                 /* the object is on the stack so it is pinned */
3859                 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3860                 mono_gc_run_finalize (obj, NULL);
3861         }
3862         g_assert (!entry);
3863         return count;
3864 }
3865
3866 gboolean
3867 mono_gc_pending_finalizers (void)
3868 {
3869         return fin_ready_list || critical_fin_list;
3870 }
3871
3872 /*
3873  * ######################################################################
3874  * ########  registered roots support
3875  * ######################################################################
3876  */
3877
3878 /*
3879  * We do not coalesce roots.
3880  */
3881 static int
3882 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3883 {
3884         RootRecord new_root;
3885         int i;
3886         LOCK_GC;
3887         for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3888                 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3889                 /* we allow changing the size and the descriptor (for thread statics etc) */
3890                 if (root) {
3891                         size_t old_size = root->end_root - start;
3892                         root->end_root = start + size;
3893                         g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3894                                           ((root->root_desc == 0) && (descr == NULL)));
3895                         root->root_desc = (mword)descr;
3896                         roots_size += size;
3897                         roots_size -= old_size;
3898                         UNLOCK_GC;
3899                         return TRUE;
3900                 }
3901         }
3902
3903         new_root.end_root = start + size;
3904         new_root.root_desc = (mword)descr;
3905
3906         sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3907         roots_size += size;
3908
3909         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);
3910
3911         UNLOCK_GC;
3912         return TRUE;
3913 }
3914
3915 int
3916 mono_gc_register_root (char *start, size_t size, void *descr)
3917 {
3918         return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3919 }
3920
3921 int
3922 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3923 {
3924         return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3925 }
3926
3927 void
3928 mono_gc_deregister_root (char* addr)
3929 {
3930         int root_type;
3931         RootRecord root;
3932
3933         LOCK_GC;
3934         for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3935                 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3936                         roots_size -= (root.end_root - addr);
3937         }
3938         UNLOCK_GC;
3939 }
3940
3941 /*
3942  * ######################################################################
3943  * ########  Thread handling (stop/start code)
3944  * ######################################################################
3945  */
3946
3947 unsigned int sgen_global_stop_count = 0;
3948
3949 int
3950 sgen_get_current_collection_generation (void)
3951 {
3952         return current_collection_generation;
3953 }
3954
3955 void
3956 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3957 {
3958         gc_callbacks = *callbacks;
3959 }
3960
3961 MonoGCCallbacks *
3962 mono_gc_get_gc_callbacks ()
3963 {
3964         return &gc_callbacks;
3965 }
3966
3967 /* Variables holding start/end nursery so it won't have to be passed at every call */
3968 static void *scan_area_arg_start, *scan_area_arg_end;
3969
3970 void
3971 mono_gc_conservatively_scan_area (void *start, void *end)
3972 {
3973         conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3974 }
3975
3976 void*
3977 mono_gc_scan_object (void *obj)
3978 {
3979         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3980         current_object_ops.copy_or_mark_object (&obj, data->queue);
3981         return obj;
3982 }
3983
3984 /*
3985  * Mark from thread stacks and registers.
3986  */
3987 static void
3988 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3989 {
3990         SgenThreadInfo *info;
3991
3992         scan_area_arg_start = start_nursery;
3993         scan_area_arg_end = end_nursery;
3994
3995         FOREACH_THREAD (info) {
3996                 if (info->skip) {
3997                         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);
3998                         continue;
3999                 }
4000                 if (info->gc_disabled) {
4001                         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);
4002                         continue;
4003                 }
4004
4005                 if (!info->joined_stw) {
4006                         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);
4007                         continue;
4008                 }
4009
4010                 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 ());
4011                 if (!info->thread_is_dying) {
4012                         if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
4013                                 UserCopyOrMarkData data = { NULL, queue };
4014                                 set_user_copy_or_mark_data (&data);
4015                                 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
4016                                 set_user_copy_or_mark_data (NULL);
4017                         } else if (!precise) {
4018                                 if (!conservative_stack_mark) {
4019                                         fprintf (stderr, "Precise stack mark not supported - disabling.\n");
4020                                         conservative_stack_mark = TRUE;
4021                                 }
4022                                 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
4023                         }
4024                 }
4025
4026                 if (!info->thread_is_dying && !precise) {
4027 #ifdef USE_MONO_CTX
4028                         conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
4029                                 start_nursery, end_nursery, PIN_TYPE_STACK);
4030 #else
4031                         conservatively_pin_objects_from (&info->regs, &info->regs + ARCH_NUM_REGS,
4032                                         start_nursery, end_nursery, PIN_TYPE_STACK);
4033 #endif
4034                 }
4035         } END_FOREACH_THREAD
4036 }
4037
4038 static gboolean
4039 ptr_on_stack (void *ptr)
4040 {
4041         gpointer stack_start = &stack_start;
4042         SgenThreadInfo *info = mono_thread_info_current ();
4043
4044         if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
4045                 return TRUE;
4046         return FALSE;
4047 }
4048
4049 static void*
4050 sgen_thread_register (SgenThreadInfo* info, void *addr)
4051 {
4052         LOCK_GC;
4053 #ifndef HAVE_KW_THREAD
4054         info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
4055
4056         g_assert (!mono_native_tls_get_value (thread_info_key));
4057         mono_native_tls_set_value (thread_info_key, info);
4058 #else
4059         sgen_thread_info = info;
4060 #endif
4061
4062 #if !defined(__MACH__)
4063         info->stop_count = -1;
4064         info->signal = 0;
4065 #endif
4066         info->skip = 0;
4067         info->joined_stw = FALSE;
4068         info->doing_handshake = FALSE;
4069         info->thread_is_dying = FALSE;
4070         info->stack_start = NULL;
4071         info->stopped_ip = NULL;
4072         info->stopped_domain = NULL;
4073 #ifdef USE_MONO_CTX
4074         memset (&info->ctx, 0, sizeof (MonoContext));
4075 #else
4076         memset (&info->regs, 0, sizeof (info->regs));
4077 #endif
4078
4079         sgen_init_tlab_info (info);
4080
4081         binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4082
4083         /* try to get it with attributes first */
4084 #if (defined(HAVE_PTHREAD_GETATTR_NP) || defined(HAVE_PTHREAD_ATTR_GET_NP)) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4085   {
4086      size_t size;
4087      void *sstart;
4088      pthread_attr_t attr;
4089
4090 #if defined(HAVE_PTHREAD_GETATTR_NP)
4091     /* Linux */
4092     pthread_getattr_np (pthread_self (), &attr);
4093 #elif defined(HAVE_PTHREAD_ATTR_GET_NP)
4094     /* BSD */
4095     pthread_attr_init (&attr);
4096     pthread_attr_get_np (pthread_self (), &attr);
4097 #else
4098 #error Cannot determine which API is needed to retrieve pthread attributes.
4099 #endif
4100
4101      pthread_attr_getstack (&attr, &sstart, &size);
4102      info->stack_start_limit = sstart;
4103      info->stack_end = (char*)sstart + size;
4104      pthread_attr_destroy (&attr);
4105   }
4106 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4107                  info->stack_end = (char*)pthread_get_stackaddr_np (pthread_self ());
4108                  info->stack_start_limit = (char*)info->stack_end - pthread_get_stacksize_np (pthread_self ());
4109 #else
4110         {
4111                 /* FIXME: we assume the stack grows down */
4112                 gsize stack_bottom = (gsize)addr;
4113                 stack_bottom += 4095;
4114                 stack_bottom &= ~4095;
4115                 info->stack_end = (char*)stack_bottom;
4116         }
4117 #endif
4118
4119 #ifdef HAVE_KW_THREAD
4120         stack_end = info->stack_end;
4121 #endif
4122
4123         SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
4124
4125         if (gc_callbacks.thread_attach_func)
4126                 info->runtime_data = gc_callbacks.thread_attach_func ();
4127
4128         UNLOCK_GC;
4129         return info;
4130 }
4131
4132 static void
4133 sgen_thread_unregister (SgenThreadInfo *p)
4134 {
4135         /* If a delegate is passed to native code and invoked on a thread we dont
4136          * know about, the jit will register it with mono_jit_thread_attach, but
4137          * we have no way of knowing when that thread goes away.  SGen has a TSD
4138          * so we assume that if the domain is still registered, we can detach
4139          * the thread
4140          */
4141         if (mono_domain_get ())
4142                 mono_thread_detach (mono_thread_current ());
4143
4144         p->thread_is_dying = TRUE;
4145
4146         /*
4147         There is a race condition between a thread finishing executing and been removed
4148         from the GC thread set.
4149         This happens on posix systems when TLS data is been cleaned-up, libpthread will
4150         set the thread_info slot to NULL before calling the cleanup function. This
4151         opens a window in which the thread is registered but has a NULL TLS.
4152
4153         The suspend signal handler needs TLS data to know where to store thread state
4154         data or otherwise it will simply ignore the thread.
4155
4156         This solution works because the thread doing STW will wait until all threads been
4157         suspended handshake back, so there is no race between the doing_hankshake test
4158         and the suspend_thread call.
4159
4160         This is not required on systems that do synchronous STW as those can deal with
4161         the above race at suspend time.
4162
4163         FIXME: I believe we could avoid this by using mono_thread_info_lookup when
4164         mono_thread_info_current returns NULL. Or fix mono_thread_info_lookup to do so.
4165         */
4166 #if (defined(__MACH__) && MONO_MACH_ARCH_SUPPORTED) || !defined(HAVE_PTHREAD_KILL)
4167         LOCK_GC;
4168 #else
4169         while (!TRYLOCK_GC) {
4170                 SgenThreadInfo *current = mono_thread_info_current ();
4171                 if (current)
4172                         SGEN_ASSERT (0, current == p, "If there's a current thread info, it must be correct.");
4173                 /*
4174                  * If we have a current thread info, the signal
4175                  * handler will eventually suspend us.  If not, we
4176                  * need to do it by hand.
4177                  */
4178                 if (current || !sgen_park_current_thread_if_doing_handshake (p))
4179                         g_usleep (50);
4180         }
4181         MONO_GC_LOCKED ();
4182 #endif
4183
4184         binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4185         SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)mono_thread_info_get_tid (p));
4186
4187         if (gc_callbacks.thread_detach_func) {
4188                 gc_callbacks.thread_detach_func (p->runtime_data);
4189                 p->runtime_data = NULL;
4190         }
4191
4192         mono_threads_unregister_current_thread (p);
4193         UNLOCK_GC;
4194 }
4195
4196
4197 static void
4198 sgen_thread_attach (SgenThreadInfo *info)
4199 {
4200         LOCK_GC;
4201         /*this is odd, can we get attached before the gc is inited?*/
4202         init_stats ();
4203         UNLOCK_GC;
4204
4205         if (gc_callbacks.thread_attach_func && !info->runtime_data)
4206                 info->runtime_data = gc_callbacks.thread_attach_func ();
4207 }
4208 gboolean
4209 mono_gc_register_thread (void *baseptr)
4210 {
4211         return mono_thread_info_attach (baseptr) != NULL;
4212 }
4213
4214 /*
4215  * mono_gc_set_stack_end:
4216  *
4217  *   Set the end of the current threads stack to STACK_END. The stack space between
4218  * STACK_END and the real end of the threads stack will not be scanned during collections.
4219  */
4220 void
4221 mono_gc_set_stack_end (void *stack_end)
4222 {
4223         SgenThreadInfo *info;
4224
4225         LOCK_GC;
4226         info = mono_thread_info_current ();
4227         if (info) {
4228                 g_assert (stack_end < info->stack_end);
4229                 info->stack_end = stack_end;
4230         }
4231         UNLOCK_GC;
4232 }
4233
4234 #if USE_PTHREAD_INTERCEPT
4235
4236
4237 int
4238 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4239 {
4240         return pthread_create (new_thread, attr, start_routine, arg);
4241 }
4242
4243 int
4244 mono_gc_pthread_join (pthread_t thread, void **retval)
4245 {
4246         return pthread_join (thread, retval);
4247 }
4248
4249 int
4250 mono_gc_pthread_detach (pthread_t thread)
4251 {
4252         return pthread_detach (thread);
4253 }
4254
4255 void
4256 mono_gc_pthread_exit (void *retval)
4257 {
4258         mono_thread_info_dettach ();
4259         pthread_exit (retval);
4260 }
4261
4262 #endif /* USE_PTHREAD_INTERCEPT */
4263
4264 /*
4265  * ######################################################################
4266  * ########  Write barriers
4267  * ######################################################################
4268  */
4269
4270 /*
4271  * Note: the write barriers first do the needed GC work and then do the actual store:
4272  * this way the value is visible to the conservative GC scan after the write barrier
4273  * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4274  * the conservative scan, otherwise by the remembered set scan.
4275  */
4276 void
4277 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4278 {
4279         HEAVY_STAT (++stat_wbarrier_set_field);
4280         if (ptr_in_nursery (field_ptr)) {
4281                 *(void**)field_ptr = value;
4282                 return;
4283         }
4284         SGEN_LOG (8, "Adding remset at %p", field_ptr);
4285         if (value)
4286                 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4287
4288         remset.wbarrier_set_field (obj, field_ptr, value);
4289 }
4290
4291 void
4292 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4293 {
4294         HEAVY_STAT (++stat_wbarrier_set_arrayref);
4295         if (ptr_in_nursery (slot_ptr)) {
4296                 *(void**)slot_ptr = value;
4297                 return;
4298         }
4299         SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4300         if (value)
4301                 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4302
4303         remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4304 }
4305
4306 void
4307 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4308 {
4309         HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4310         /*This check can be done without taking a lock since dest_ptr array is pinned*/
4311         if (ptr_in_nursery (dest_ptr) || count <= 0) {
4312                 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4313                 return;
4314         }
4315
4316 #ifdef SGEN_BINARY_PROTOCOL
4317         {
4318                 int i;
4319                 for (i = 0; i < count; ++i) {
4320                         gpointer dest = (gpointer*)dest_ptr + i;
4321                         gpointer obj = *((gpointer*)src_ptr + i);
4322                         if (obj)
4323                                 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4324                 }
4325         }
4326 #endif
4327
4328         remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4329 }
4330
4331 static char *found_obj;
4332
4333 static void
4334 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4335 {
4336         char *ptr = user_data;
4337
4338         if (ptr >= obj && ptr < obj + size) {
4339                 g_assert (!found_obj);
4340                 found_obj = obj;
4341         }
4342 }
4343
4344 /* for use in the debugger */
4345 char* find_object_for_ptr (char *ptr);
4346 char*
4347 find_object_for_ptr (char *ptr)
4348 {
4349         if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4350                 found_obj = NULL;
4351                 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4352                                 find_object_for_ptr_callback, ptr, TRUE);
4353                 if (found_obj)
4354                         return found_obj;
4355         }
4356
4357         found_obj = NULL;
4358         sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4359         if (found_obj)
4360                 return found_obj;
4361
4362         /*
4363          * Very inefficient, but this is debugging code, supposed to
4364          * be called from gdb, so we don't care.
4365          */
4366         found_obj = NULL;
4367         major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4368         return found_obj;
4369 }
4370
4371 void
4372 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4373 {
4374         gpointer obj;
4375
4376         HEAVY_STAT (++stat_wbarrier_generic_store);
4377
4378 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4379         /* FIXME: ptr_in_heap must be called with the GC lock held */
4380         if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4381                 char *start = find_object_for_ptr (ptr);
4382                 MonoObject *value = *(MonoObject**)ptr;
4383                 LOCK_GC;
4384                 g_assert (start);
4385                 if (start) {
4386                         MonoObject *obj = (MonoObject*)start;
4387                         if (obj->vtable->domain != value->vtable->domain)
4388                                 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4389                 }
4390                 UNLOCK_GC;
4391         }
4392 #endif
4393
4394         obj = *(gpointer*)ptr;
4395         if (obj)
4396                 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4397
4398         if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4399                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4400                 return;
4401         }
4402
4403         /*
4404          * We need to record old->old pointer locations for the
4405          * concurrent collector.
4406          */
4407         if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4408                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4409                 return;
4410         }
4411
4412         SGEN_LOG (8, "Adding remset at %p", ptr);
4413
4414         remset.wbarrier_generic_nostore (ptr);
4415 }
4416
4417 void
4418 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4419 {
4420         SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4421         *(void**)ptr = value;
4422         if (ptr_in_nursery (value))
4423                 mono_gc_wbarrier_generic_nostore (ptr);
4424         sgen_dummy_use (value);
4425 }
4426
4427 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4428 {
4429         mword *dest = _dest;
4430         mword *src = _src;
4431
4432         while (size) {
4433                 if (bitmap & 0x1)
4434                         mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4435                 else
4436                         *dest = *src;
4437                 ++src;
4438                 ++dest;
4439                 size -= SIZEOF_VOID_P;
4440                 bitmap >>= 1;
4441         }
4442 }
4443
4444 #ifdef SGEN_BINARY_PROTOCOL
4445 #undef HANDLE_PTR
4446 #define HANDLE_PTR(ptr,obj) do {                                        \
4447                 gpointer o = *(gpointer*)(ptr);                         \
4448                 if ((o)) {                                              \
4449                         gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4450                         binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4451                 }                                                       \
4452         } while (0)
4453
4454 static void
4455 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4456 {
4457 #define SCAN_OBJECT_NOVTABLE
4458 #include "sgen-scan-object.h"
4459 }
4460 #endif
4461
4462 void
4463 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4464 {
4465         HEAVY_STAT (++stat_wbarrier_value_copy);
4466         g_assert (klass->valuetype);
4467
4468         SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4469
4470         if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4471                 size_t element_size = mono_class_value_size (klass, NULL);
4472                 size_t size = count * element_size;
4473                 mono_gc_memmove (dest, src, size);
4474                 return;
4475         }
4476
4477 #ifdef SGEN_BINARY_PROTOCOL
4478         {
4479                 size_t element_size = mono_class_value_size (klass, NULL);
4480                 int i;
4481                 for (i = 0; i < count; ++i) {
4482                         scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4483                                         (char*)src + i * element_size - sizeof (MonoObject),
4484                                         (mword) klass->gc_descr);
4485                 }
4486         }
4487 #endif
4488
4489         remset.wbarrier_value_copy (dest, src, count, klass);
4490 }
4491
4492 /**
4493  * mono_gc_wbarrier_object_copy:
4494  *
4495  * Write barrier to call when obj is the result of a clone or copy of an object.
4496  */
4497 void
4498 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4499 {
4500         int size;
4501
4502         HEAVY_STAT (++stat_wbarrier_object_copy);
4503
4504         if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4505                 size = mono_object_class (obj)->instance_size;
4506                 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4507                                 size - sizeof (MonoObject));
4508                 return;
4509         }
4510
4511 #ifdef SGEN_BINARY_PROTOCOL
4512         scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4513 #endif
4514
4515         remset.wbarrier_object_copy (obj, src);
4516 }
4517
4518
4519 /*
4520  * ######################################################################
4521  * ########  Other mono public interface functions.
4522  * ######################################################################
4523  */
4524
4525 #define REFS_SIZE 128
4526 typedef struct {
4527         void *data;
4528         MonoGCReferences callback;
4529         int flags;
4530         int count;
4531         int called;
4532         MonoObject *refs [REFS_SIZE];
4533         uintptr_t offsets [REFS_SIZE];
4534 } HeapWalkInfo;
4535
4536 #undef HANDLE_PTR
4537 #define HANDLE_PTR(ptr,obj)     do {    \
4538                 if (*(ptr)) {   \
4539                         if (hwi->count == REFS_SIZE) {  \
4540                                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);    \
4541                                 hwi->count = 0; \
4542                                 hwi->called = 1;        \
4543                         }       \
4544                         hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start;  \
4545                         hwi->refs [hwi->count++] = *(ptr);      \
4546                 }       \
4547         } while (0)
4548
4549 static void
4550 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4551 {
4552 #include "sgen-scan-object.h"
4553 }
4554
4555 static void
4556 walk_references (char *start, size_t size, void *data)
4557 {
4558         HeapWalkInfo *hwi = data;
4559         hwi->called = 0;
4560         hwi->count = 0;
4561         collect_references (hwi, start, size);
4562         if (hwi->count || !hwi->called)
4563                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4564 }
4565
4566 /**
4567  * mono_gc_walk_heap:
4568  * @flags: flags for future use
4569  * @callback: a function pointer called for each object in the heap
4570  * @data: a user data pointer that is passed to callback
4571  *
4572  * This function can be used to iterate over all the live objects in the heap:
4573  * for each object, @callback is invoked, providing info about the object's
4574  * location in memory, its class, its size and the objects it references.
4575  * For each referenced object it's offset from the object address is
4576  * reported in the offsets array.
4577  * The object references may be buffered, so the callback may be invoked
4578  * multiple times for the same object: in all but the first call, the size
4579  * argument will be zero.
4580  * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4581  * profiler event handler.
4582  *
4583  * Returns: a non-zero value if the GC doesn't support heap walking
4584  */
4585 int
4586 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4587 {
4588         HeapWalkInfo hwi;
4589
4590         hwi.flags = flags;
4591         hwi.callback = callback;
4592         hwi.data = data;
4593
4594         sgen_clear_nursery_fragments ();
4595         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4596
4597         major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4598         sgen_los_iterate_objects (walk_references, &hwi);
4599
4600         return 0;
4601 }
4602
4603 void
4604 mono_gc_collect (int generation)
4605 {
4606         LOCK_GC;
4607         if (generation > 1)
4608                 generation = 1;
4609         sgen_perform_collection (0, generation, "user request", TRUE);
4610         UNLOCK_GC;
4611 }
4612
4613 int
4614 mono_gc_max_generation (void)
4615 {
4616         return 1;
4617 }
4618
4619 int
4620 mono_gc_collection_count (int generation)
4621 {
4622         if (generation == 0)
4623                 return stat_minor_gcs;
4624         return stat_major_gcs;
4625 }
4626
4627 int64_t
4628 mono_gc_get_used_size (void)
4629 {
4630         gint64 tot = 0;
4631         LOCK_GC;
4632         tot = los_memory_usage;
4633         tot += nursery_section->next_data - nursery_section->data;
4634         tot += major_collector.get_used_size ();
4635         /* FIXME: account for pinned objects */
4636         UNLOCK_GC;
4637         return tot;
4638 }
4639
4640 int
4641 mono_gc_get_los_limit (void)
4642 {
4643         return MAX_SMALL_OBJ_SIZE;
4644 }
4645
4646 gboolean
4647 mono_gc_user_markers_supported (void)
4648 {
4649         return TRUE;
4650 }
4651
4652 gboolean
4653 mono_object_is_alive (MonoObject* o)
4654 {
4655         return TRUE;
4656 }
4657
4658 int
4659 mono_gc_get_generation (MonoObject *obj)
4660 {
4661         if (ptr_in_nursery (obj))
4662                 return 0;
4663         return 1;
4664 }
4665
4666 void
4667 mono_gc_enable_events (void)
4668 {
4669 }
4670
4671 void
4672 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4673 {
4674         sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4675 }
4676
4677 void
4678 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4679 {
4680         sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4681 }
4682
4683 MonoObject*
4684 mono_gc_weak_link_get (void **link_addr)
4685 {
4686         void * volatile *link_addr_volatile;
4687         void *ptr;
4688         MonoObject *obj;
4689  retry:
4690         link_addr_volatile = link_addr;
4691         ptr = (void*)*link_addr_volatile;
4692         /*
4693          * At this point we have a hidden pointer.  If the GC runs
4694          * here, it will not recognize the hidden pointer as a
4695          * reference, and if the object behind it is not referenced
4696          * elsewhere, it will be freed.  Once the world is restarted
4697          * we reveal the pointer, giving us a pointer to a freed
4698          * object.  To make sure we don't return it, we load the
4699          * hidden pointer again.  If it's still the same, we can be
4700          * sure the object reference is valid.
4701          */
4702         if (ptr)
4703                 obj = (MonoObject*) REVEAL_POINTER (ptr);
4704         else
4705                 return NULL;
4706
4707         mono_memory_barrier ();
4708
4709         /*
4710          * During the second bridge processing step the world is
4711          * running again.  That step processes all weak links once
4712          * more to null those that refer to dead objects.  Before that
4713          * is completed, those links must not be followed, so we
4714          * conservatively wait for bridge processing when any weak
4715          * link is dereferenced.
4716          */
4717         if (G_UNLIKELY (bridge_processing_in_progress))
4718                 mono_gc_wait_for_bridge_processing ();
4719
4720         if ((void*)*link_addr_volatile != ptr)
4721                 goto retry;
4722
4723         return obj;
4724 }
4725
4726 gboolean
4727 mono_gc_ephemeron_array_add (MonoObject *obj)
4728 {
4729         EphemeronLinkNode *node;
4730
4731         LOCK_GC;
4732
4733         node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4734         if (!node) {
4735                 UNLOCK_GC;
4736                 return FALSE;
4737         }
4738         node->array = (char*)obj;
4739         node->next = ephemeron_list;
4740         ephemeron_list = node;
4741
4742         SGEN_LOG (5, "Registered ephemeron array %p", obj);
4743
4744         UNLOCK_GC;
4745         return TRUE;
4746 }
4747
4748 gboolean
4749 mono_gc_set_allow_synchronous_major (gboolean flag)
4750 {
4751         if (!major_collector.is_concurrent)
4752                 return flag;
4753
4754         allow_synchronous_major = flag;
4755         return TRUE;
4756 }
4757
4758 void*
4759 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4760 {
4761         void *result;
4762         LOCK_INTERRUPTION;
4763         result = func (data);
4764         UNLOCK_INTERRUPTION;
4765         return result;
4766 }
4767
4768 gboolean
4769 mono_gc_is_gc_thread (void)
4770 {
4771         gboolean result;
4772         LOCK_GC;
4773         result = mono_thread_info_current () != NULL;
4774         UNLOCK_GC;
4775         return result;
4776 }
4777
4778 static gboolean
4779 is_critical_method (MonoMethod *method)
4780 {
4781         return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4782 }
4783
4784 void
4785 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4786 {
4787         va_list ap;
4788
4789         va_start (ap, description_format);
4790
4791         fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4792         vfprintf (stderr, description_format, ap);
4793         if (fallback)
4794                 fprintf (stderr, " - %s", fallback);
4795         fprintf (stderr, "\n");
4796
4797         va_end (ap);
4798 }
4799
4800 static gboolean
4801 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4802 {
4803         char *endptr;
4804         double val = strtod (opt, &endptr);
4805         if (endptr == opt) {
4806                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4807                 return FALSE;
4808         }
4809         else if (val < min || val > max) {
4810                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4811                 return FALSE;
4812         }
4813         *result = val;
4814         return TRUE;
4815 }
4816
4817 void
4818 mono_gc_base_init (void)
4819 {
4820         MonoThreadInfoCallbacks cb;
4821         const char *env;
4822         char **opts, **ptr;
4823         char *major_collector_opt = NULL;
4824         char *minor_collector_opt = NULL;
4825         glong max_heap = 0;
4826         glong soft_limit = 0;
4827         int num_workers;
4828         int result;
4829         int dummy;
4830         gboolean debug_print_allowance = FALSE;
4831         double allowance_ratio = 0, save_target = 0;
4832         gboolean have_split_nursery = FALSE;
4833         gboolean cement_enabled = TRUE;
4834
4835         do {
4836                 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4837                 switch (result) {
4838                 case 1:
4839                         /* already inited */
4840                         return;
4841                 case -1:
4842                         /* being inited by another thread */
4843                         g_usleep (1000);
4844                         break;
4845                 case 0:
4846                         /* we will init it */
4847                         break;
4848                 default:
4849                         g_assert_not_reached ();
4850                 }
4851         } while (result != 0);
4852
4853         LOCK_INIT (gc_mutex);
4854
4855         pagesize = mono_pagesize ();
4856         gc_debug_file = stderr;
4857
4858         cb.thread_register = sgen_thread_register;
4859         cb.thread_unregister = sgen_thread_unregister;
4860         cb.thread_attach = sgen_thread_attach;
4861         cb.mono_method_is_critical = (gpointer)is_critical_method;
4862 #ifndef HOST_WIN32
4863         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4864 #endif
4865
4866         mono_threads_init (&cb, sizeof (SgenThreadInfo));
4867
4868         LOCK_INIT (sgen_interruption_mutex);
4869         LOCK_INIT (pin_queue_mutex);
4870
4871         init_user_copy_or_mark_key ();
4872
4873         if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4874                 opts = g_strsplit (env, ",", -1);
4875                 for (ptr = opts; *ptr; ++ptr) {
4876                         char *opt = *ptr;
4877                         if (g_str_has_prefix (opt, "major=")) {
4878                                 opt = strchr (opt, '=') + 1;
4879                                 major_collector_opt = g_strdup (opt);
4880                         } else if (g_str_has_prefix (opt, "minor=")) {
4881                                 opt = strchr (opt, '=') + 1;
4882                                 minor_collector_opt = g_strdup (opt);
4883                         }
4884                 }
4885         } else {
4886                 opts = NULL;
4887         }
4888
4889         init_stats ();
4890         sgen_init_internal_allocator ();
4891         sgen_init_nursery_allocator ();
4892         sgen_init_fin_weak_hash ();
4893
4894         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4895         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4896         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4897         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4898
4899 #ifndef HAVE_KW_THREAD
4900         mono_native_tls_alloc (&thread_info_key, NULL);
4901 #endif
4902
4903         /*
4904          * This needs to happen before any internal allocations because
4905          * it inits the small id which is required for hazard pointer
4906          * operations.
4907          */
4908         sgen_os_init ();
4909
4910         mono_thread_info_attach (&dummy);
4911
4912         if (!minor_collector_opt) {
4913                 sgen_simple_nursery_init (&sgen_minor_collector);
4914         } else {
4915                 if (!strcmp (minor_collector_opt, "simple")) {
4916                 use_simple_nursery:
4917                         sgen_simple_nursery_init (&sgen_minor_collector);
4918                 } else if (!strcmp (minor_collector_opt, "split")) {
4919                         sgen_split_nursery_init (&sgen_minor_collector);
4920                         have_split_nursery = TRUE;
4921                 } else {
4922                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4923                         goto use_simple_nursery;
4924                 }
4925         }
4926
4927         if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4928         use_marksweep_major:
4929                 sgen_marksweep_init (&major_collector);
4930         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4931                 sgen_marksweep_fixed_init (&major_collector);
4932         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4933                 sgen_marksweep_par_init (&major_collector);
4934         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4935                 sgen_marksweep_fixed_par_init (&major_collector);
4936         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4937                 sgen_marksweep_conc_init (&major_collector);
4938         } else {
4939                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4940                 goto use_marksweep_major;
4941         }
4942
4943         if (have_split_nursery && major_collector.is_parallel) {
4944                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4945                 have_split_nursery = FALSE;
4946         }
4947
4948         num_workers = mono_cpu_count ();
4949         g_assert (num_workers > 0);
4950         if (num_workers > 16)
4951                 num_workers = 16;
4952
4953         ///* Keep this the default for now */
4954         /* Precise marking is broken on all supported targets. Disable until fixed. */
4955         conservative_stack_mark = TRUE;
4956
4957         sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4958
4959         if (opts) {
4960                 gboolean usage_printed = FALSE;
4961
4962                 for (ptr = opts; *ptr; ++ptr) {
4963                         char *opt = *ptr;
4964                         if (!strcmp (opt, ""))
4965                                 continue;
4966                         if (g_str_has_prefix (opt, "major="))
4967                                 continue;
4968                         if (g_str_has_prefix (opt, "minor="))
4969                                 continue;
4970                         if (g_str_has_prefix (opt, "max-heap-size=")) {
4971                                 glong max_heap_candidate = 0;
4972                                 opt = strchr (opt, '=') + 1;
4973                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4974                                         max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(glong)(mono_pagesize () - 1);
4975                                         if (max_heap != max_heap_candidate)
4976                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4977                                 } else {
4978                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4979                                 }
4980                                 continue;
4981                         }
4982                         if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4983                                 opt = strchr (opt, '=') + 1;
4984                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4985                                         if (soft_limit <= 0) {
4986                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4987                                                 soft_limit = 0;
4988                                         }
4989                                 } else {
4990                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4991                                 }
4992                                 continue;
4993                         }
4994                         if (g_str_has_prefix (opt, "workers=")) {
4995                                 long val;
4996                                 char *endptr;
4997                                 if (!major_collector.is_parallel) {
4998                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
4999                                         continue;
5000                                 }
5001                                 opt = strchr (opt, '=') + 1;
5002                                 val = strtol (opt, &endptr, 10);
5003                                 if (!*opt || *endptr) {
5004                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
5005                                         continue;
5006                                 }
5007                                 if (val <= 0 || val > 16) {
5008                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
5009                                         continue;
5010                                 }
5011                                 num_workers = (int)val;
5012                                 continue;
5013                         }
5014                         if (g_str_has_prefix (opt, "stack-mark=")) {
5015                                 opt = strchr (opt, '=') + 1;
5016                                 if (!strcmp (opt, "precise")) {
5017                                         conservative_stack_mark = FALSE;
5018                                 } else if (!strcmp (opt, "conservative")) {
5019                                         conservative_stack_mark = TRUE;
5020                                 } else {
5021                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
5022                                                         "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
5023                                 }
5024                                 continue;
5025                         }
5026                         if (g_str_has_prefix (opt, "bridge=")) {
5027                                 opt = strchr (opt, '=') + 1;
5028                                 sgen_register_test_bridge_callbacks (g_strdup (opt));
5029                                 continue;
5030                         }
5031 #ifdef USER_CONFIG
5032                         if (g_str_has_prefix (opt, "nursery-size=")) {
5033                                 long val;
5034                                 opt = strchr (opt, '=') + 1;
5035                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
5036 #ifdef SGEN_ALIGN_NURSERY
5037                                         if ((val & (val - 1))) {
5038                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
5039                                                 continue;
5040                                         }
5041
5042                                         if (val < SGEN_MAX_NURSERY_WASTE) {
5043                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
5044                                                                 "`nursery-size` must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
5045                                                 continue;
5046                                         }
5047
5048                                         sgen_nursery_size = val;
5049                                         sgen_nursery_bits = 0;
5050                                         while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
5051                                                 ;
5052 #else
5053                                         sgen_nursery_size = val;
5054 #endif
5055                                 } else {
5056                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
5057                                         continue;
5058                                 }
5059                                 continue;
5060                         }
5061 #endif
5062                         if (g_str_has_prefix (opt, "save-target-ratio=")) {
5063                                 double val;
5064                                 opt = strchr (opt, '=') + 1;
5065                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
5066                                                 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
5067                                         save_target = val;
5068                                 }
5069                                 continue;
5070                         }
5071                         if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
5072                                 double val;
5073                                 opt = strchr (opt, '=') + 1;
5074                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
5075                                                 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
5076                                         allowance_ratio = val;
5077                                 }
5078                                 continue;
5079                         }
5080                         if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
5081                                 if (!major_collector.is_concurrent) {
5082                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
5083                                         continue;
5084                                 }
5085
5086                                 opt = strchr (opt, '=') + 1;
5087
5088                                 if (!strcmp (opt, "yes")) {
5089                                         allow_synchronous_major = TRUE;
5090                                 } else if (!strcmp (opt, "no")) {
5091                                         allow_synchronous_major = FALSE;
5092                                 } else {
5093                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
5094                                         continue;
5095                                 }
5096                         }
5097
5098                         if (!strcmp (opt, "cementing")) {
5099                                 if (major_collector.is_parallel) {
5100                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported for the parallel major collector.");
5101                                         continue;
5102                                 }
5103                                 cement_enabled = TRUE;
5104                                 continue;
5105                         }
5106                         if (!strcmp (opt, "no-cementing")) {
5107                                 cement_enabled = FALSE;
5108                                 continue;
5109                         }
5110
5111                         if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
5112                                 continue;
5113
5114                         if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
5115                                 continue;
5116
5117                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5118
5119                         if (usage_printed)
5120                                 continue;
5121
5122                         fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
5123                         fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5124                         fprintf (stderr, "  soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
5125                         fprintf (stderr, "  nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5126                         fprintf (stderr, "  major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
5127                         fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
5128                         fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
5129                         fprintf (stderr, "  stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
5130                         fprintf (stderr, "  [no-]cementing\n");
5131                         if (major_collector.is_concurrent)
5132                                 fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
5133                         if (major_collector.print_gc_param_usage)
5134                                 major_collector.print_gc_param_usage ();
5135                         if (sgen_minor_collector.print_gc_param_usage)
5136                                 sgen_minor_collector.print_gc_param_usage ();
5137                         fprintf (stderr, " Experimental options:\n");
5138                         fprintf (stderr, "  save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
5139                         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);
5140                         fprintf (stderr, "\n");
5141
5142                         usage_printed = TRUE;
5143                 }
5144                 g_strfreev (opts);
5145         }
5146
5147         if (major_collector.is_parallel) {
5148                 cement_enabled = FALSE;
5149                 sgen_workers_init (num_workers);
5150         } else if (major_collector.is_concurrent) {
5151                 sgen_workers_init (1);
5152         }
5153
5154         if (major_collector_opt)
5155                 g_free (major_collector_opt);
5156
5157         if (minor_collector_opt)
5158                 g_free (minor_collector_opt);
5159
5160         alloc_nursery ();
5161
5162         sgen_cement_init (cement_enabled);
5163
5164         if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
5165                 gboolean usage_printed = FALSE;
5166
5167                 opts = g_strsplit (env, ",", -1);
5168                 for (ptr = opts; ptr && *ptr; ptr ++) {
5169                         char *opt = *ptr;
5170                         if (!strcmp (opt, ""))
5171                                 continue;
5172                         if (opt [0] >= '0' && opt [0] <= '9') {
5173                                 gc_debug_level = atoi (opt);
5174                                 opt++;
5175                                 if (opt [0] == ':')
5176                                         opt++;
5177                                 if (opt [0]) {
5178 #ifdef HOST_WIN32
5179                                         char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
5180 #else
5181                                         char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
5182 #endif
5183                                         gc_debug_file = fopen (rf, "wb");
5184                                         if (!gc_debug_file)
5185                                                 gc_debug_file = stderr;
5186                                         g_free (rf);
5187                                 }
5188                         } else if (!strcmp (opt, "print-allowance")) {
5189                                 debug_print_allowance = TRUE;
5190                         } else if (!strcmp (opt, "print-pinning")) {
5191                                 do_pin_stats = TRUE;
5192                         } else if (!strcmp (opt, "verify-before-allocs")) {
5193                                 verify_before_allocs = 1;
5194                                 has_per_allocation_action = TRUE;
5195                         } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5196                                 char *arg = strchr (opt, '=') + 1;
5197                                 verify_before_allocs = atoi (arg);
5198                                 has_per_allocation_action = TRUE;
5199                         } else if (!strcmp (opt, "collect-before-allocs")) {
5200                                 collect_before_allocs = 1;
5201                                 has_per_allocation_action = TRUE;
5202                         } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5203                                 char *arg = strchr (opt, '=') + 1;
5204                                 has_per_allocation_action = TRUE;
5205                                 collect_before_allocs = atoi (arg);
5206                         } else if (!strcmp (opt, "verify-before-collections")) {
5207                                 whole_heap_check_before_collection = TRUE;
5208                         } else if (!strcmp (opt, "check-at-minor-collections")) {
5209                                 consistency_check_at_minor_collection = TRUE;
5210                                 nursery_clear_policy = CLEAR_AT_GC;
5211                         } else if (!strcmp (opt, "mod-union-consistency-check")) {
5212                                 if (!major_collector.is_concurrent) {
5213                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
5214                                         continue;
5215                                 }
5216                                 mod_union_consistency_check = TRUE;
5217                         } else if (!strcmp (opt, "check-mark-bits")) {
5218                                 check_mark_bits_after_major_collection = TRUE;
5219                         } else if (!strcmp (opt, "check-nursery-pinned")) {
5220                                 check_nursery_objects_pinned = TRUE;
5221                         } else if (!strcmp (opt, "xdomain-checks")) {
5222                                 xdomain_checks = TRUE;
5223                         } else if (!strcmp (opt, "clear-at-gc")) {
5224                                 nursery_clear_policy = CLEAR_AT_GC;
5225                         } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5226                                 nursery_clear_policy = CLEAR_AT_GC;
5227                         } else if (!strcmp (opt, "check-scan-starts")) {
5228                                 do_scan_starts_check = TRUE;
5229                         } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5230                                 do_verify_nursery = TRUE;
5231                         } else if (!strcmp (opt, "check-concurrent")) {
5232                                 if (!major_collector.is_concurrent) {
5233                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5234                                         continue;
5235                                 }
5236                                 do_concurrent_checks = TRUE;
5237                         } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5238                                 do_dump_nursery_content = TRUE;
5239                         } else if (!strcmp (opt, "no-managed-allocator")) {
5240                                 sgen_set_use_managed_allocator (FALSE);
5241                         } else if (!strcmp (opt, "disable-minor")) {
5242                                 disable_minor_collections = TRUE;
5243                         } else if (!strcmp (opt, "disable-major")) {
5244                                 disable_major_collections = TRUE;
5245                         } else if (g_str_has_prefix (opt, "heap-dump=")) {
5246                                 char *filename = strchr (opt, '=') + 1;
5247                                 nursery_clear_policy = CLEAR_AT_GC;
5248                                 heap_dump_file = fopen (filename, "w");
5249                                 if (heap_dump_file) {
5250                                         fprintf (heap_dump_file, "<sgen-dump>\n");
5251                                         do_pin_stats = TRUE;
5252                                 }
5253 #ifdef SGEN_BINARY_PROTOCOL
5254                         } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5255                                 char *filename = strchr (opt, '=') + 1;
5256                                 binary_protocol_init (filename);
5257 #endif
5258                         } else {
5259                                 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5260
5261                                 if (usage_printed)
5262                                         continue;
5263
5264                                 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);
5265                                 fprintf (stderr, "Valid <option>s are:\n");
5266                                 fprintf (stderr, "  collect-before-allocs[=<n>]\n");
5267                                 fprintf (stderr, "  verify-before-allocs[=<n>]\n");
5268                                 fprintf (stderr, "  check-at-minor-collections\n");
5269                                 fprintf (stderr, "  check-mark-bits\n");
5270                                 fprintf (stderr, "  check-nursery-pinned\n");
5271                                 fprintf (stderr, "  verify-before-collections\n");
5272                                 fprintf (stderr, "  verify-nursery-at-minor-gc\n");
5273                                 fprintf (stderr, "  dump-nursery-at-minor-gc\n");
5274                                 fprintf (stderr, "  disable-minor\n");
5275                                 fprintf (stderr, "  disable-major\n");
5276                                 fprintf (stderr, "  xdomain-checks\n");
5277                                 fprintf (stderr, "  check-concurrent\n");
5278                                 fprintf (stderr, "  clear-at-gc\n");
5279                                 fprintf (stderr, "  clear-nursery-at-gc\n");
5280                                 fprintf (stderr, "  check-scan-starts\n");
5281                                 fprintf (stderr, "  no-managed-allocator\n");
5282                                 fprintf (stderr, "  print-allowance\n");
5283                                 fprintf (stderr, "  print-pinning\n");
5284                                 fprintf (stderr, "  heap-dump=<filename>\n");
5285 #ifdef SGEN_BINARY_PROTOCOL
5286                                 fprintf (stderr, "  binary-protocol=<filename>\n");
5287 #endif
5288                                 fprintf (stderr, "\n");
5289
5290                                 usage_printed = TRUE;
5291                         }
5292                 }
5293                 g_strfreev (opts);
5294         }
5295
5296         if (major_collector.is_parallel) {
5297                 if (heap_dump_file) {
5298                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5299                         fclose (heap_dump_file);
5300                         heap_dump_file = NULL;
5301                 }
5302                 if (do_pin_stats) {
5303                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5304                         do_pin_stats = FALSE;
5305                 }
5306         }
5307
5308         if (major_collector.post_param_init)
5309                 major_collector.post_param_init (&major_collector);
5310
5311         sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5312
5313         memset (&remset, 0, sizeof (remset));
5314
5315         sgen_card_table_init (&remset);
5316
5317         gc_initialized = 1;
5318 }
5319
5320 const char *
5321 mono_gc_get_gc_name (void)
5322 {
5323         return "sgen";
5324 }
5325
5326 static MonoMethod *write_barrier_method;
5327
5328 gboolean
5329 sgen_is_critical_method (MonoMethod *method)
5330 {
5331         return (method == write_barrier_method || sgen_is_managed_allocator (method));
5332 }
5333
5334 gboolean
5335 sgen_has_critical_method (void)
5336 {
5337         return write_barrier_method || sgen_has_managed_allocator ();
5338 }
5339
5340 #ifndef DISABLE_JIT
5341
5342 static void
5343 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5344 {
5345         memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5346 #ifdef SGEN_ALIGN_NURSERY
5347         // if (ptr_in_nursery (ptr)) return;
5348         /*
5349          * Masking out the bits might be faster, but we would have to use 64 bit
5350          * immediates, which might be slower.
5351          */
5352         mono_mb_emit_ldarg (mb, 0);
5353         mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5354         mono_mb_emit_byte (mb, CEE_SHR_UN);
5355         mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5356         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5357
5358         if (!major_collector.is_concurrent) {
5359                 // if (!ptr_in_nursery (*ptr)) return;
5360                 mono_mb_emit_ldarg (mb, 0);
5361                 mono_mb_emit_byte (mb, CEE_LDIND_I);
5362                 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5363                 mono_mb_emit_byte (mb, CEE_SHR_UN);
5364                 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5365                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5366         }
5367 #else
5368         int label_continue1, label_continue2;
5369         int dereferenced_var;
5370
5371         // if (ptr < (sgen_get_nursery_start ())) goto continue;
5372         mono_mb_emit_ldarg (mb, 0);
5373         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5374         label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5375
5376         // if (ptr >= sgen_get_nursery_end ())) goto continue;
5377         mono_mb_emit_ldarg (mb, 0);
5378         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5379         label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5380
5381         // Otherwise return
5382         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5383
5384         // continue:
5385         mono_mb_patch_branch (mb, label_continue_1);
5386         mono_mb_patch_branch (mb, label_continue_2);
5387
5388         // Dereference and store in local var
5389         dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5390         mono_mb_emit_ldarg (mb, 0);
5391         mono_mb_emit_byte (mb, CEE_LDIND_I);
5392         mono_mb_emit_stloc (mb, dereferenced_var);
5393
5394         if (!major_collector.is_concurrent) {
5395                 // if (*ptr < sgen_get_nursery_start ()) return;
5396                 mono_mb_emit_ldloc (mb, dereferenced_var);
5397                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5398                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5399
5400                 // if (*ptr >= sgen_get_nursery_end ()) return;
5401                 mono_mb_emit_ldloc (mb, dereferenced_var);
5402                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5403                 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5404         }
5405 #endif
5406 }
5407 #endif
5408
5409 MonoMethod*
5410 mono_gc_get_write_barrier (void)
5411 {
5412         MonoMethod *res;
5413         MonoMethodBuilder *mb;
5414         MonoMethodSignature *sig;
5415 #ifdef MANAGED_WBARRIER
5416         int i, nursery_check_labels [3];
5417
5418 #ifdef HAVE_KW_THREAD
5419         int stack_end_offset = -1;
5420
5421         MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5422         g_assert (stack_end_offset != -1);
5423 #endif
5424 #endif
5425
5426         // FIXME: Maybe create a separate version for ctors (the branch would be
5427         // correctly predicted more times)
5428         if (write_barrier_method)
5429                 return write_barrier_method;
5430
5431         /* Create the IL version of mono_gc_barrier_generic_store () */
5432         sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5433         sig->ret = &mono_defaults.void_class->byval_arg;
5434         sig->params [0] = &mono_defaults.int_class->byval_arg;
5435
5436         mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5437
5438 #ifndef DISABLE_JIT
5439 #ifdef MANAGED_WBARRIER
5440         emit_nursery_check (mb, nursery_check_labels);
5441         /*
5442         addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5443         *addr = 1;
5444
5445         sgen_cardtable:
5446                 LDC_PTR sgen_cardtable
5447
5448         address >> CARD_BITS
5449                 LDARG_0
5450                 LDC_I4 CARD_BITS
5451                 SHR_UN
5452         if (SGEN_HAVE_OVERLAPPING_CARDS) {
5453                 LDC_PTR card_table_mask
5454                 AND
5455         }
5456         AND
5457         ldc_i4_1
5458         stind_i1
5459         */
5460         mono_mb_emit_ptr (mb, sgen_cardtable);
5461         mono_mb_emit_ldarg (mb, 0);
5462         mono_mb_emit_icon (mb, CARD_BITS);
5463         mono_mb_emit_byte (mb, CEE_SHR_UN);
5464 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5465         mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5466         mono_mb_emit_byte (mb, CEE_AND);
5467 #endif
5468         mono_mb_emit_byte (mb, CEE_ADD);
5469         mono_mb_emit_icon (mb, 1);
5470         mono_mb_emit_byte (mb, CEE_STIND_I1);
5471
5472         // return;
5473         for (i = 0; i < 3; ++i) {
5474                 if (nursery_check_labels [i])
5475                         mono_mb_patch_branch (mb, nursery_check_labels [i]);
5476         }
5477         mono_mb_emit_byte (mb, CEE_RET);
5478 #else
5479         mono_mb_emit_ldarg (mb, 0);
5480         mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5481         mono_mb_emit_byte (mb, CEE_RET);
5482 #endif
5483 #endif
5484         res = mono_mb_create_method (mb, sig, 16);
5485         mono_mb_free (mb);
5486
5487         mono_loader_lock ();
5488         if (write_barrier_method) {
5489                 /* Already created */
5490                 mono_free_method (res);
5491         } else {
5492                 /* double-checked locking */
5493                 mono_memory_barrier ();
5494                 write_barrier_method = res;
5495         }
5496         mono_loader_unlock ();
5497
5498         return write_barrier_method;
5499 }
5500
5501 char*
5502 mono_gc_get_description (void)
5503 {
5504         return g_strdup ("sgen");
5505 }
5506
5507 void
5508 mono_gc_set_desktop_mode (void)
5509 {
5510 }
5511
5512 gboolean
5513 mono_gc_is_moving (void)
5514 {
5515         return TRUE;
5516 }
5517
5518 gboolean
5519 mono_gc_is_disabled (void)
5520 {
5521         return FALSE;
5522 }
5523
5524 #ifdef HOST_WIN32
5525 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5526 {
5527         return TRUE;
5528 }
5529 #endif
5530
5531 NurseryClearPolicy
5532 sgen_get_nursery_clear_policy (void)
5533 {
5534         return nursery_clear_policy;
5535 }
5536
5537 MonoVTable*
5538 sgen_get_array_fill_vtable (void)
5539 {
5540         if (!array_fill_vtable) {
5541                 static MonoClass klass;
5542                 static MonoVTable vtable;
5543                 gsize bmap;
5544
5545                 MonoDomain *domain = mono_get_root_domain ();
5546                 g_assert (domain);
5547
5548                 klass.element_class = mono_defaults.byte_class;
5549                 klass.rank = 1;
5550                 klass.instance_size = sizeof (MonoArray);
5551                 klass.sizes.element_size = 1;
5552                 klass.name = "array_filler_type";
5553
5554                 vtable.klass = &klass;
5555                 bmap = 0;
5556                 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5557                 vtable.rank = 1;
5558
5559                 array_fill_vtable = &vtable;
5560         }
5561         return array_fill_vtable;
5562 }
5563
5564 void
5565 sgen_gc_lock (void)
5566 {
5567         LOCK_GC;
5568 }
5569
5570 void
5571 sgen_gc_unlock (void)
5572 {
5573         UNLOCK_GC;
5574 }
5575
5576 void
5577 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5578 {
5579         major_collector.iterate_live_block_ranges (callback);
5580 }
5581
5582 void
5583 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5584 {
5585         major_collector.scan_card_table (FALSE, queue);
5586 }
5587
5588 SgenMajorCollector*
5589 sgen_get_major_collector (void)
5590 {
5591         return &major_collector;
5592 }
5593
5594 void mono_gc_set_skip_thread (gboolean skip)
5595 {
5596         SgenThreadInfo *info = mono_thread_info_current ();
5597
5598         LOCK_GC;
5599         info->gc_disabled = skip;
5600         UNLOCK_GC;
5601 }
5602
5603 SgenRemeberedSet*
5604 sgen_get_remset (void)
5605 {
5606         return &remset;
5607 }
5608
5609 guint
5610 mono_gc_get_vtable_bits (MonoClass *class)
5611 {
5612         if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5613                 return SGEN_GC_BIT_BRIDGE_OBJECT;
5614         return 0;
5615 }
5616
5617 void
5618 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5619 {
5620         // FIXME:
5621 }
5622
5623
5624 void
5625 sgen_check_whole_heap_stw (void)
5626 {
5627         sgen_stop_world (0);
5628         sgen_clear_nursery_fragments ();
5629         sgen_check_whole_heap (FALSE);
5630         sgen_restart_world (0, NULL);
5631 }
5632
5633 void
5634 sgen_gc_event_moves (void)
5635 {
5636         if (moved_objects_idx) {
5637                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5638                 moved_objects_idx = 0;
5639         }
5640 }
5641
5642 #endif /* HAVE_SGEN_GC */