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_generic_store_atomic = 0;
 321 static int stat_wbarrier_set_root = 0;
 322 static int stat_wbarrier_value_copy = 0;
 323 static int stat_wbarrier_object_copy = 0;
 324 #endif
 325
 326 int stat_minor_gcs = 0;
 327 int stat_major_gcs = 0;
 328
 329 static long long stat_pinned_objects = 0;
 330
 331 static long long time_minor_pre_collection_fragment_clear = 0;
 332 static long long time_minor_pinning = 0;
 333 static long long time_minor_scan_remsets = 0;
 334 static long long time_minor_scan_pinned = 0;
 335 static long long time_minor_scan_registered_roots = 0;
 336 static long long time_minor_scan_thread_data = 0;
 337 static long long time_minor_finish_gray_stack = 0;
 338 static long long time_minor_fragment_creation = 0;
 339
 340 static long long time_major_pre_collection_fragment_clear = 0;
 341 static long long time_major_pinning = 0;
 342 static long long time_major_scan_pinned = 0;
 343 static long long time_major_scan_registered_roots = 0;
 344 static long long time_major_scan_thread_data = 0;
 345 static long long time_major_scan_alloc_pinned = 0;
 346 static long long time_major_scan_finalized = 0;
 347 static long long time_major_scan_big_objects = 0;
 348 static long long time_major_finish_gray_stack = 0;
 349 static long long time_major_free_bigobjs = 0;
 350 static long long time_major_los_sweep = 0;
 351 static long long time_major_sweep = 0;
 352 static long long time_major_fragment_creation = 0;
 353
 354 int gc_debug_level = 0;
 355 FILE* gc_debug_file;
 356
 357 /*
 358 void
 359 mono_gc_flush_info (void)
 360 {
 361         fflush (gc_debug_file);
 362 }
 363 */
 364
 365 #define TV_DECLARE SGEN_TV_DECLARE
 366 #define TV_GETTIME SGEN_TV_GETTIME
 367 #define TV_ELAPSED SGEN_TV_ELAPSED
 368 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
 369
 370 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
 371
 372 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
 373
 374 #define object_is_forwarded     SGEN_OBJECT_IS_FORWARDED
 375 #define object_is_pinned        SGEN_OBJECT_IS_PINNED
 376 #define pin_object              SGEN_PIN_OBJECT
 377 #define unpin_object            SGEN_UNPIN_OBJECT
 378
 379 #define ptr_in_nursery sgen_ptr_in_nursery
 380
 381 #define LOAD_VTABLE     SGEN_LOAD_VTABLE
 382
 383 static const char*
 384 safe_name (void* obj)
 385 {
 386         MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
 387         return vt->klass->name;
 388 }
 389
 390 #define safe_object_get_size    sgen_safe_object_get_size
 391
 392 const char*
 393 sgen_safe_name (void* obj)
 394 {
 395         return safe_name (obj);
 396 }
 397
 398 /*
 399  * ######################################################################
 400  * ########  Global data.
 401  * ######################################################################
 402  */
 403 LOCK_DECLARE (gc_mutex);
 404
 405 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
 406
 407 static mword pagesize = 4096;
 408 int degraded_mode = 0;
 409
 410 static mword bytes_pinned_from_failed_allocation = 0;
 411
 412 GCMemSection *nursery_section = NULL;
 413 static mword lowest_heap_address = ~(mword)0;
 414 static mword highest_heap_address = 0;
 415
 416 LOCK_DECLARE (sgen_interruption_mutex);
 417 static LOCK_DECLARE (pin_queue_mutex);
 418
 419 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
 420 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
 421
 422 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
 423 struct _FinalizeReadyEntry {
 424         FinalizeReadyEntry *next;
 425         void *object;
 426 };
 427
 428 typedef struct _EphemeronLinkNode EphemeronLinkNode;
 429
 430 struct _EphemeronLinkNode {
 431         EphemeronLinkNode *next;
 432         char *array;
 433 };
 434
 435 typedef struct {
 436        void *key;
 437        void *value;
 438 } Ephemeron;
 439
 440 int current_collection_generation = -1;
 441 volatile gboolean concurrent_collection_in_progress = FALSE;
 442
 443 /* objects that are ready to be finalized */
 444 static FinalizeReadyEntry *fin_ready_list = NULL;
 445 static FinalizeReadyEntry *critical_fin_list = NULL;
 446
 447 static EphemeronLinkNode *ephemeron_list;
 448
 449 /* registered roots: the key to the hash is the root start address */
 450 /*
 451  * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
 452  */
 453 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
 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         SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
 457 };
 458 static mword roots_size = 0; /* amount of memory in the root set */
 459
 460 #define GC_ROOT_NUM 32
 461 typedef struct {
 462         int count;              /* must be the first field */
 463         void *objects [GC_ROOT_NUM];
 464         int root_types [GC_ROOT_NUM];
 465         uintptr_t extra_info [GC_ROOT_NUM];
 466 } GCRootReport;
 467
 468 static void
 469 notify_gc_roots (GCRootReport *report)
 470 {
 471         if (!report->count)
 472                 return;
 473         mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
 474         report->count = 0;
 475 }
 476
 477 static void
 478 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
 479 {
 480         if (report->count == GC_ROOT_NUM)
 481                 notify_gc_roots (report);
 482         report->objects [report->count] = object;
 483         report->root_types [report->count] = rtype;
 484         report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
 485 }
 486
 487 MonoNativeTlsKey thread_info_key;
 488
 489 #ifdef HAVE_KW_THREAD
 490 __thread SgenThreadInfo *sgen_thread_info;
 491 __thread char *stack_end;
 492 #endif
 493
 494 /* The size of a TLAB */
 495 /* The bigger the value, the less often we have to go to the slow path to allocate a new
 496  * one, but the more space is wasted by threads not allocating much memory.
 497  * FIXME: Tune this.
 498  * FIXME: Make this self-tuning for each thread.
 499  */
 500 guint32 tlab_size = (1024 * 4);
 501
 502 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
 503
 504 /* Functions supplied by the runtime to be called by the GC */
 505 static MonoGCCallbacks gc_callbacks;
 506
 507 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
 508 #define ALLOC_ALIGN_BITS        SGEN_ALLOC_ALIGN_BITS
 509
 510 #define ALIGN_UP                SGEN_ALIGN_UP
 511
 512 #define MOVED_OBJECTS_NUM 64
 513 static void *moved_objects [MOVED_OBJECTS_NUM];
 514 static int moved_objects_idx = 0;
 515
 516 /* Vtable of the objects used to fill out nursery fragments before a collection */
 517 static MonoVTable *array_fill_vtable;
 518
 519 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
 520 MonoNativeThreadId main_gc_thread = NULL;
 521 #endif
 522
 523 /*Object was pinned during the current collection*/
 524 static mword objects_pinned;
 525
 526 /*
 527  * ######################################################################
 528  * ########  Macros and function declarations.
 529  * ######################################################################
 530  */
 531
 532 inline static void*
 533 align_pointer (void *ptr)
 534 {
 535         mword p = (mword)ptr;
 536         p += sizeof (gpointer) - 1;
 537         p &= ~ (sizeof (gpointer) - 1);
 538         return (void*)p;
 539 }
 540
 541 typedef SgenGrayQueue GrayQueue;
 542
 543 /* forward declarations */
 544 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
 545 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
 546 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
 547 static void report_finalizer_roots (void);
 548 static void report_registered_roots (void);
 549
 550 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
 551 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
 552 static void finish_gray_stack (int generation, GrayQueue *queue);
 553
 554 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
 555
 556
 557 static void init_stats (void);
 558
 559 static int mark_ephemerons_in_range (ScanCopyContext ctx);
 560 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
 561 static void null_ephemerons_for_domain (MonoDomain *domain);
 562
 563 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
 564
 565 SgenObjectOperations current_object_ops;
 566 SgenMajorCollector major_collector;
 567 SgenMinorCollector sgen_minor_collector;
 568 static GrayQueue gray_queue;
 569
 570 static SgenRemeberedSet remset;
 571
 572 /* The gray queue to use from the main collection thread. */
 573 #define WORKERS_DISTRIBUTE_GRAY_QUEUE   (&gray_queue)
 574
 575 /*
 576  * The gray queue a worker job must use.  If we're not parallel or
 577  * concurrent, we use the main gray queue.
 578  */
 579 static SgenGrayQueue*
 580 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
 581 {
 582         return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
 583 }
 584
 585 static void
 586 gray_queue_redirect (SgenGrayQueue *queue)
 587 {
 588         gboolean wake = FALSE;
 589
 590
 591         for (;;) {
 592                 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
 593                 if (!section)
 594                         break;
 595                 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
 596                 wake = TRUE;
 597         }
 598
 599         if (wake) {
 600                 g_assert (concurrent_collection_in_progress ||
 601                                 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
 602                 if (sgen_workers_have_started ()) {
 603                         sgen_workers_wake_up_all ();
 604                 } else {
 605                         if (concurrent_collection_in_progress)
 606                                 g_assert (current_collection_generation == -1);
 607                 }
 608         }
 609 }
 610
 611 static gboolean
 612 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
 613 {
 614         MonoObject *o = (MonoObject*)(obj);
 615         MonoObject *ref = (MonoObject*)*(ptr);
 616         int offset = (char*)(ptr) - (char*)o;
 617
 618         if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
 619                 return TRUE;
 620         if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
 621                 return TRUE;
 622
 623 #ifndef DISABLE_REMOTING
 624         if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
 625                         offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
 626                 return TRUE;
 627 #endif
 628         /* Thread.cached_culture_info */
 629         if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
 630                         !strcmp (ref->vtable->klass->name, "CultureInfo") &&
 631                         !strcmp(o->vtable->klass->name_space, "System") &&
 632                         !strcmp(o->vtable->klass->name, "Object[]"))
 633                 return TRUE;
 634         /*
 635          *  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
 636          * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
 637          * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
 638          * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
 639          * 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
 640          * 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
 641          * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
 642          * 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
 643          * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
 644          */
 645         if (!strcmp (ref->vtable->klass->name_space, "System") &&
 646                         !strcmp (ref->vtable->klass->name, "Byte[]") &&
 647                         !strcmp (o->vtable->klass->name_space, "System.IO") &&
 648                         !strcmp (o->vtable->klass->name, "MemoryStream"))
 649                 return TRUE;
 650         /* append_job() in threadpool.c */
 651         if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
 652                         !strcmp (ref->vtable->klass->name, "AsyncResult") &&
 653                         !strcmp (o->vtable->klass->name_space, "System") &&
 654                         !strcmp (o->vtable->klass->name, "Object[]") &&
 655                         mono_thread_pool_is_queue_array ((MonoArray*) o))
 656                 return TRUE;
 657         return FALSE;
 658 }
 659
 660 static void
 661 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
 662 {
 663         MonoObject *o = (MonoObject*)(obj);
 664         MonoObject *ref = (MonoObject*)*(ptr);
 665         int offset = (char*)(ptr) - (char*)o;
 666         MonoClass *class;
 667         MonoClassField *field;
 668         char *str;
 669
 670         if (!ref || ref->vtable->domain == domain)
 671                 return;
 672         if (is_xdomain_ref_allowed (ptr, obj, domain))
 673                 return;
 674
 675         field = NULL;
 676         for (class = o->vtable->klass; class; class = class->parent) {
 677                 int i;
 678
 679                 for (i = 0; i < class->field.count; ++i) {
 680                         if (class->fields[i].offset == offset) {
 681                                 field = &class->fields[i];
 682                                 break;
 683                         }
 684                 }
 685                 if (field)
 686                         break;
 687         }
 688
 689         if (ref->vtable->klass == mono_defaults.string_class)
 690                 str = mono_string_to_utf8 ((MonoString*)ref);
 691         else
 692                 str = NULL;
 693         g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s)  -  pointed to by:\n",
 694                         o, o->vtable->klass->name_space, o->vtable->klass->name,
 695                         offset, field ? field->name : "",
 696                         ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
 697         mono_gc_scan_for_specific_ref (o, TRUE);
 698         if (str)
 699                 g_free (str);
 700 }
 701
 702 #undef HANDLE_PTR
 703 #define HANDLE_PTR(ptr,obj)     check_reference_for_xdomain ((ptr), (obj), domain)
 704
 705 static void
 706 scan_object_for_xdomain_refs (char *start, mword size, void *data)
 707 {
 708         MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
 709
 710         #include "sgen-scan-object.h"
 711 }
 712
 713 static gboolean scan_object_for_specific_ref_precise = TRUE;
 714
 715 #undef HANDLE_PTR
 716 #define HANDLE_PTR(ptr,obj) do {                \
 717         if ((MonoObject*)*(ptr) == key) {       \
 718         g_print ("found ref to %p in object %p (%s) at offset %td\n",   \
 719                         key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
 720         }                                                               \
 721         } while (0)
 722
 723 static void
 724 scan_object_for_specific_ref (char *start, MonoObject *key)
 725 {
 726         char *forwarded;
 727
 728         if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
 729                 start = forwarded;
 730
 731         if (scan_object_for_specific_ref_precise) {
 732                 #include "sgen-scan-object.h"
 733         } else {
 734                 mword *words = (mword*)start;
 735                 size_t size = safe_object_get_size ((MonoObject*)start);
 736                 int i;
 737                 for (i = 0; i < size / sizeof (mword); ++i) {
 738                         if (words [i] == (mword)key) {
 739                                 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
 740                                                 key, start, safe_name (start), i * sizeof (mword));
 741                         }
 742                 }
 743         }
 744 }
 745
 746 void
 747 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
 748 {
 749         while (start < end) {
 750                 size_t size;
 751                 char *obj;
 752
 753                 if (!*(void**)start) {
 754                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
 755                         continue;
 756                 }
 757
 758                 if (allow_flags) {
 759                         if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
 760                                 obj = start;
 761                 } else {
 762                         obj = start;
 763                 }
 764
 765                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
 766
 767                 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
 768                         callback (obj, size, data);
 769
 770                 start += size;
 771         }
 772 }
 773
 774 static void
 775 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
 776 {
 777         scan_object_for_specific_ref (obj, key);
 778 }
 779
 780 static void
 781 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
 782 {
 783         if (key != obj)
 784                 return;
 785         g_print ("found ref to %p in root record %p\n", key, root);
 786 }
 787
 788 static MonoObject *check_key = NULL;
 789 static RootRecord *check_root = NULL;
 790
 791 static void
 792 check_root_obj_specific_ref_from_marker (void **obj)
 793 {
 794         check_root_obj_specific_ref (check_root, check_key, *obj);
 795 }
 796
 797 static void
 798 scan_roots_for_specific_ref (MonoObject *key, int root_type)
 799 {
 800         void **start_root;
 801         RootRecord *root;
 802         check_key = key;
 803
 804         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 805                 mword desc = root->root_desc;
 806
 807                 check_root = root;
 808
 809                 switch (desc & ROOT_DESC_TYPE_MASK) {
 810                 case ROOT_DESC_BITMAP:
 811                         desc >>= ROOT_DESC_TYPE_SHIFT;
 812                         while (desc) {
 813                                 if (desc & 1)
 814                                         check_root_obj_specific_ref (root, key, *start_root);
 815                                 desc >>= 1;
 816                                 start_root++;
 817                         }
 818                         return;
 819                 case ROOT_DESC_COMPLEX: {
 820                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 821                         int bwords = (*bitmap_data) - 1;
 822                         void **start_run = start_root;
 823                         bitmap_data++;
 824                         while (bwords-- > 0) {
 825                                 gsize bmap = *bitmap_data++;
 826                                 void **objptr = start_run;
 827                                 while (bmap) {
 828                                         if (bmap & 1)
 829                                                 check_root_obj_specific_ref (root, key, *objptr);
 830                                         bmap >>= 1;
 831                                         ++objptr;
 832                                 }
 833                                 start_run += GC_BITS_PER_WORD;
 834                         }
 835                         break;
 836                 }
 837                 case ROOT_DESC_USER: {
 838                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 839                         marker (start_root, check_root_obj_specific_ref_from_marker);
 840                         break;
 841                 }
 842                 case ROOT_DESC_RUN_LEN:
 843                         g_assert_not_reached ();
 844                 default:
 845                         g_assert_not_reached ();
 846                 }
 847         } SGEN_HASH_TABLE_FOREACH_END;
 848
 849         check_key = NULL;
 850         check_root = NULL;
 851 }
 852
 853 void
 854 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
 855 {
 856         void **ptr;
 857         RootRecord *root;
 858
 859         scan_object_for_specific_ref_precise = precise;
 860
 861         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 862                         (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
 863
 864         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 865
 866         sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
 867
 868         scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
 869         scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
 870
 871         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
 872                 while (ptr < (void**)root->end_root) {
 873                         check_root_obj_specific_ref (root, *ptr, key);
 874                         ++ptr;
 875                 }
 876         } SGEN_HASH_TABLE_FOREACH_END;
 877 }
 878
 879 static gboolean
 880 need_remove_object_for_domain (char *start, MonoDomain *domain)
 881 {
 882         if (mono_object_domain (start) == domain) {
 883                 SGEN_LOG (4, "Need to cleanup object %p", start);
 884                 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
 885                 return TRUE;
 886         }
 887         return FALSE;
 888 }
 889
 890 static void
 891 process_object_for_domain_clearing (char *start, MonoDomain *domain)
 892 {
 893         GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
 894         if (vt->klass == mono_defaults.internal_thread_class)
 895                 g_assert (mono_object_domain (start) == mono_get_root_domain ());
 896         /* The object could be a proxy for an object in the domain
 897            we're deleting. */
 898 #ifndef DISABLE_REMOTING
 899         if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
 900                 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
 901
 902                 /* The server could already have been zeroed out, so
 903                    we need to check for that, too. */
 904                 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
 905                         SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
 906                         ((MonoRealProxy*)start)->unwrapped_server = NULL;
 907                 }
 908         }
 909 #endif
 910 }
 911
 912 static MonoDomain *check_domain = NULL;
 913
 914 static void
 915 check_obj_not_in_domain (void **o)
 916 {
 917         g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
 918 }
 919
 920 static void
 921 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
 922 {
 923         void **start_root;
 924         RootRecord *root;
 925         check_domain = domain;
 926         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
 927                 mword desc = root->root_desc;
 928
 929                 /* The MonoDomain struct is allowed to hold
 930                    references to objects in its own domain. */
 931                 if (start_root == (void**)domain)
 932                         continue;
 933
 934                 switch (desc & ROOT_DESC_TYPE_MASK) {
 935                 case ROOT_DESC_BITMAP:
 936                         desc >>= ROOT_DESC_TYPE_SHIFT;
 937                         while (desc) {
 938                                 if ((desc & 1) && *start_root)
 939                                         check_obj_not_in_domain (*start_root);
 940                                 desc >>= 1;
 941                                 start_root++;
 942                         }
 943                         break;
 944                 case ROOT_DESC_COMPLEX: {
 945                         gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
 946                         int bwords = (*bitmap_data) - 1;
 947                         void **start_run = start_root;
 948                         bitmap_data++;
 949                         while (bwords-- > 0) {
 950                                 gsize bmap = *bitmap_data++;
 951                                 void **objptr = start_run;
 952                                 while (bmap) {
 953                                         if ((bmap & 1) && *objptr)
 954                                                 check_obj_not_in_domain (*objptr);
 955                                         bmap >>= 1;
 956                                         ++objptr;
 957                                 }
 958                                 start_run += GC_BITS_PER_WORD;
 959                         }
 960                         break;
 961                 }
 962                 case ROOT_DESC_USER: {
 963                         MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
 964                         marker (start_root, check_obj_not_in_domain);
 965                         break;
 966                 }
 967                 case ROOT_DESC_RUN_LEN:
 968                         g_assert_not_reached ();
 969                 default:
 970                         g_assert_not_reached ();
 971                 }
 972         } SGEN_HASH_TABLE_FOREACH_END;
 973
 974         check_domain = NULL;
 975 }
 976
 977 static void
 978 check_for_xdomain_refs (void)
 979 {
 980         LOSObject *bigobj;
 981
 982         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
 983                         (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
 984
 985         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
 986
 987         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
 988                 scan_object_for_xdomain_refs (bigobj->data, sgen_los_object_size (bigobj), NULL);
 989 }
 990
 991 static gboolean
 992 clear_domain_process_object (char *obj, MonoDomain *domain)
 993 {
 994         gboolean remove;
 995
 996         process_object_for_domain_clearing (obj, domain);
 997         remove = need_remove_object_for_domain (obj, domain);
 998
 999         if (remove && ((MonoObject*)obj)->synchronisation) {
1000                 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
1001                 if (dislink)
1002                         sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
1003         }
1004
1005         return remove;
1006 }
1007
1008 static void
1009 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1010 {
1011         if (clear_domain_process_object (obj, domain))
1012                 memset (obj, 0, size);
1013 }
1014
1015 static void
1016 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1017 {
1018         clear_domain_process_object (obj, domain);
1019 }
1020
1021 static void
1022 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1023 {
1024         if (need_remove_object_for_domain (obj, domain))
1025                 major_collector.free_non_pinned_object (obj, size);
1026 }
1027
1028 static void
1029 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1030 {
1031         if (need_remove_object_for_domain (obj, domain))
1032                 major_collector.free_pinned_object (obj, size);
1033 }
1034
1035 /*
1036  * When appdomains are unloaded we can easily remove objects that have finalizers,
1037  * but all the others could still be present in random places on the heap.
1038  * We need a sweep to get rid of them even though it's going to be costly
1039  * with big heaps.
1040  * The reason we need to remove them is because we access the vtable and class
1041  * structures to know the object size and the reference bitmap: once the domain is
1042  * unloaded the point to random memory.
1043  */
1044 void
1045 mono_gc_clear_domain (MonoDomain * domain)
1046 {
1047         LOSObject *bigobj, *prev;
1048         int i;
1049
1050         LOCK_GC;
1051
1052         binary_protocol_domain_unload_begin (domain);
1053
1054         sgen_stop_world (0);
1055
1056         if (concurrent_collection_in_progress)
1057                 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
1058         g_assert (!concurrent_collection_in_progress);
1059
1060         sgen_process_fin_stage_entries ();
1061         sgen_process_dislink_stage_entries ();
1062
1063         sgen_clear_nursery_fragments ();
1064
1065         if (xdomain_checks && domain != mono_get_root_domain ()) {
1066                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1067                 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1068                 check_for_xdomain_refs ();
1069         }
1070
1071         /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1072         to memory returned to the OS.*/
1073         null_ephemerons_for_domain (domain);
1074
1075         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1076                 sgen_null_links_for_domain (domain, i);
1077
1078         for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1079                 sgen_remove_finalizers_for_domain (domain, i);
1080
1081         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1082                         (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1083
1084         /* We need two passes over major and large objects because
1085            freeing such objects might give their memory back to the OS
1086            (in the case of large objects) or obliterate its vtable
1087            (pinned objects with major-copying or pinned and non-pinned
1088            objects with major-mark&sweep), but we might need to
1089            dereference a pointer from an object to another object if
1090            the first object is a proxy. */
1091         major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1092         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1093                 clear_domain_process_object (bigobj->data, domain);
1094
1095         prev = NULL;
1096         for (bigobj = los_object_list; bigobj;) {
1097                 if (need_remove_object_for_domain (bigobj->data, domain)) {
1098                         LOSObject *to_free = bigobj;
1099                         if (prev)
1100                                 prev->next = bigobj->next;
1101                         else
1102                                 los_object_list = bigobj->next;
1103                         bigobj = bigobj->next;
1104                         SGEN_LOG (4, "Freeing large object %p", bigobj->data);
1105                         sgen_los_free_object (to_free);
1106                         continue;
1107                 }
1108                 prev = bigobj;
1109                 bigobj = bigobj->next;
1110         }
1111         major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1112         major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1113
1114         if (domain == mono_get_root_domain ()) {
1115                 if (G_UNLIKELY (do_pin_stats))
1116                         sgen_pin_stats_print_class_stats ();
1117                 sgen_object_layout_dump (stdout);
1118         }
1119
1120         sgen_restart_world (0, NULL);
1121
1122         binary_protocol_domain_unload_end (domain);
1123
1124         UNLOCK_GC;
1125 }
1126
1127 /*
1128  * sgen_add_to_global_remset:
1129  *
1130  *   The global remset contains locations which point into newspace after
1131  * a minor collection. This can happen if the objects they point to are pinned.
1132  *
1133  * LOCKING: If called from a parallel collector, the global remset
1134  * lock must be held.  For serial collectors that is not necessary.
1135  */
1136 void
1137 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
1138 {
1139         SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
1140
1141         HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
1142
1143         if (!major_collector.is_concurrent) {
1144                 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
1145         } else {
1146                 if (current_collection_generation == -1)
1147                         SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
1148         }
1149
1150         if (!object_is_pinned (obj))
1151                 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");
1152         else if (sgen_cement_lookup_or_register (obj))
1153                 return;
1154
1155         remset.record_pointer (ptr);
1156
1157         if (G_UNLIKELY (do_pin_stats))
1158                 sgen_pin_stats_register_global_remset (obj);
1159
1160         SGEN_LOG (8, "Adding global remset for %p", ptr);
1161         binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
1162
1163
1164 #ifdef ENABLE_DTRACE
1165         if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
1166                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
1167                 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
1168                                 vt->klass->name_space, vt->klass->name);
1169         }
1170 #endif
1171 }
1172
1173 /*
1174  * sgen_drain_gray_stack:
1175  *
1176  *   Scan objects in the gray stack until the stack is empty. This should be called
1177  * frequently after each object is copied, to achieve better locality and cache
1178  * usage.
1179  */
1180 gboolean
1181 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
1182 {
1183         char *obj;
1184         ScanObjectFunc scan_func = ctx.scan_func;
1185         GrayQueue *queue = ctx.queue;
1186
1187         if (max_objs == -1) {
1188                 for (;;) {
1189                         GRAY_OBJECT_DEQUEUE (queue, obj);
1190                         if (!obj)
1191                                 return TRUE;
1192                         SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1193                         scan_func (obj, queue);
1194                 }
1195         } else {
1196                 int i;
1197
1198                 do {
1199                         for (i = 0; i != max_objs; ++i) {
1200                                 GRAY_OBJECT_DEQUEUE (queue, obj);
1201                                 if (!obj)
1202                                         return TRUE;
1203                                 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
1204                                 scan_func (obj, queue);
1205                         }
1206                 } while (max_objs < 0);
1207                 return FALSE;
1208         }
1209 }
1210
1211 /*
1212  * Addresses from start to end are already sorted. This function finds
1213  * the object header for each address and pins the object. The
1214  * addresses must be inside the passed section.  The (start of the)
1215  * address array is overwritten with the addresses of the actually
1216  * pinned objects.  Return the number of pinned objects.
1217  */
1218 static int
1219 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1220 {
1221         void *last = NULL;
1222         int count = 0;
1223         void *search_start;
1224         void *last_obj = NULL;
1225         size_t last_obj_size = 0;
1226         void *addr;
1227         int idx;
1228         void **definitely_pinned = start;
1229         ScanObjectFunc scan_func = ctx.scan_func;
1230         SgenGrayQueue *queue = ctx.queue;
1231
1232         sgen_nursery_allocator_prepare_for_pinning ();
1233
1234         while (start < end) {
1235                 addr = *start;
1236                 /* the range check should be reduntant */
1237                 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1238                         SGEN_LOG (5, "Considering pinning addr %p", addr);
1239                         /* multiple pointers to the same object */
1240                         if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1241                                 start++;
1242                                 continue;
1243                         }
1244                         idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1245                         g_assert (idx < section->num_scan_start);
1246                         search_start = (void*)section->scan_starts [idx];
1247                         if (!search_start || search_start > addr) {
1248                                 while (idx) {
1249                                         --idx;
1250                                         search_start = section->scan_starts [idx];
1251                                         if (search_start && search_start <= addr)
1252                                                 break;
1253                                 }
1254                                 if (!search_start || search_start > addr)
1255                                         search_start = start_nursery;
1256                         }
1257                         if (search_start < last_obj)
1258                                 search_start = (char*)last_obj + last_obj_size;
1259                         /* now addr should be in an object a short distance from search_start
1260                          * Note that search_start must point to zeroed mem or point to an object.
1261                          */
1262
1263                         do {
1264                                 if (!*(void**)search_start) {
1265                                         /* Consistency check */
1266                                         /*
1267                                         for (frag = nursery_fragments; frag; frag = frag->next) {
1268                                                 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1269                                                         g_assert_not_reached ();
1270                                         }
1271                                         */
1272
1273                                         search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1274                                         continue;
1275                                 }
1276                                 last_obj = search_start;
1277                                 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1278
1279                                 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1280                                         /* Marks the beginning of a nursery fragment, skip */
1281                                 } else {
1282                                         SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
1283                                         if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1284                                                 if (scan_func) {
1285                                                         scan_func (search_start, queue);
1286                                                 } else {
1287                                                         SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1288                                                                         search_start, *(void**)search_start, safe_name (search_start), count);
1289                                                         binary_protocol_pin (search_start,
1290                                                                         (gpointer)LOAD_VTABLE (search_start),
1291                                                                         safe_object_get_size (search_start));
1292
1293 #ifdef ENABLE_DTRACE
1294                                                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1295                                                                 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
1296                                                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
1297                                                                 MONO_GC_OBJ_PINNED ((mword)search_start,
1298                                                                                 sgen_safe_object_get_size (search_start),
1299                                                                                 vt->klass->name_space, vt->klass->name, gen);
1300                                                         }
1301 #endif
1302
1303                                                         pin_object (search_start);
1304                                                         GRAY_OBJECT_ENQUEUE (queue, search_start);
1305                                                         if (G_UNLIKELY (do_pin_stats))
1306                                                                 sgen_pin_stats_register_object (search_start, last_obj_size);
1307                                                         definitely_pinned [count] = search_start;
1308                                                         count++;
1309                                                 }
1310                                                 break;
1311                                         }
1312                                 }
1313                                 /* skip to the next object */
1314                                 search_start = (void*)((char*)search_start + last_obj_size);
1315                         } while (search_start <= addr);
1316                         /* we either pinned the correct object or we ignored the addr because
1317                          * it points to unused zeroed memory.
1318                          */
1319                         last = addr;
1320                 }
1321                 start++;
1322         }
1323         //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1324         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1325                 GCRootReport report;
1326                 report.count = 0;
1327                 for (idx = 0; idx < count; ++idx)
1328                         add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1329                 notify_gc_roots (&report);
1330         }
1331         stat_pinned_objects += count;
1332         return count;
1333 }
1334
1335 void
1336 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1337 {
1338         int num_entries = section->pin_queue_num_entries;
1339         if (num_entries) {
1340                 void **start = section->pin_queue_start;
1341                 int reduced_to;
1342                 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1343                                 section->data, section->next_data, ctx);
1344                 section->pin_queue_num_entries = reduced_to;
1345                 if (!reduced_to)
1346                         section->pin_queue_start = NULL;
1347         }
1348 }
1349
1350
1351 void
1352 sgen_pin_object (void *object, GrayQueue *queue)
1353 {
1354         g_assert (!concurrent_collection_in_progress);
1355
1356         if (sgen_collection_is_parallel ()) {
1357                 LOCK_PIN_QUEUE;
1358                 /*object arrives pinned*/
1359                 sgen_pin_stage_ptr (object);
1360                 ++objects_pinned ;
1361                 UNLOCK_PIN_QUEUE;
1362         } else {
1363                 SGEN_PIN_OBJECT (object);
1364                 sgen_pin_stage_ptr (object);
1365                 ++objects_pinned;
1366                 if (G_UNLIKELY (do_pin_stats))
1367                         sgen_pin_stats_register_object (object, safe_object_get_size (object));
1368         }
1369         GRAY_OBJECT_ENQUEUE (queue, object);
1370         binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1371
1372 #ifdef ENABLE_DTRACE
1373         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1374                 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1375                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1376                 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1377         }
1378 #endif
1379 }
1380
1381 void
1382 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1383 {
1384         for (;;) {
1385                 mword vtable_word;
1386                 gboolean major_pinned = FALSE;
1387
1388                 if (sgen_ptr_in_nursery (obj)) {
1389                         if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1390                                 sgen_pin_object (obj, queue);
1391                                 break;
1392                         }
1393                 } else {
1394                         major_collector.pin_major_object (obj, queue);
1395                         major_pinned = TRUE;
1396                 }
1397
1398                 vtable_word = *(mword*)obj;
1399                 /*someone else forwarded it, update the pointer and bail out*/
1400                 if (vtable_word & SGEN_FORWARDED_BIT) {
1401                         *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1402                         break;
1403                 }
1404
1405                 /*someone pinned it, nothing to do.*/
1406                 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1407                         break;
1408         }
1409 }
1410
1411 /* Sort the addresses in array in increasing order.
1412  * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1413  */
1414 void
1415 sgen_sort_addresses (void **array, int size)
1416 {
1417         int i;
1418         void *tmp;
1419
1420         for (i = 1; i < size; ++i) {
1421                 int child = i;
1422                 while (child > 0) {
1423                         int parent = (child - 1) / 2;
1424
1425                         if (array [parent] >= array [child])
1426                                 break;
1427
1428                         tmp = array [parent];
1429                         array [parent] = array [child];
1430                         array [child] = tmp;
1431
1432                         child = parent;
1433                 }
1434         }
1435
1436         for (i = size - 1; i > 0; --i) {
1437                 int end, root;
1438                 tmp = array [i];
1439                 array [i] = array [0];
1440                 array [0] = tmp;
1441
1442                 end = i - 1;
1443                 root = 0;
1444
1445                 while (root * 2 + 1 <= end) {
1446                         int child = root * 2 + 1;
1447
1448                         if (child < end && array [child] < array [child + 1])
1449                                 ++child;
1450                         if (array [root] >= array [child])
1451                                 break;
1452
1453                         tmp = array [root];
1454                         array [root] = array [child];
1455                         array [child] = tmp;
1456
1457                         root = child;
1458                 }
1459         }
1460 }
1461
1462 /*
1463  * Scan the memory between start and end and queue values which could be pointers
1464  * to the area between start_nursery and end_nursery for later consideration.
1465  * Typically used for thread stacks.
1466  */
1467 static void
1468 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1469 {
1470         int count = 0;
1471
1472 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1473         VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1474 #endif
1475
1476         while (start < end) {
1477                 if (*start >= start_nursery && *start < end_nursery) {
1478                         /*
1479                          * *start can point to the middle of an object
1480                          * note: should we handle pointing at the end of an object?
1481                          * pinning in C# code disallows pointing at the end of an object
1482                          * but there is some small chance that an optimizing C compiler
1483                          * may keep the only reference to an object by pointing
1484                          * at the end of it. We ignore this small chance for now.
1485                          * Pointers to the end of an object are indistinguishable
1486                          * from pointers to the start of the next object in memory
1487                          * so if we allow that we'd need to pin two objects...
1488                          * We queue the pointer in an array, the
1489                          * array will then be sorted and uniqued. This way
1490                          * we can coalesce several pinning pointers and it should
1491                          * be faster since we'd do a memory scan with increasing
1492                          * addresses. Note: we can align the address to the allocation
1493                          * alignment, so the unique process is more effective.
1494                          */
1495                         mword addr = (mword)*start;
1496                         addr &= ~(ALLOC_ALIGN - 1);
1497                         if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1498                                 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1499                                 sgen_pin_stage_ptr ((void*)addr);
1500                                 count++;
1501                         }
1502                         if (G_UNLIKELY (do_pin_stats)) {
1503                                 if (ptr_in_nursery ((void*)addr))
1504                                         sgen_pin_stats_register_address ((char*)addr, pin_type);
1505                         }
1506                 }
1507                 start++;
1508         }
1509         if (count)
1510                 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1511 }
1512
1513 /*
1514  * The first thing we do in a collection is to identify pinned objects.
1515  * This function considers all the areas of memory that need to be
1516  * conservatively scanned.
1517  */
1518 static void
1519 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1520 {
1521         void **start_root;
1522         RootRecord *root;
1523         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);
1524         /* objects pinned from the API are inside these roots */
1525         SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1526                 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1527                 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1528         } SGEN_HASH_TABLE_FOREACH_END;
1529         /* now deal with the thread stacks
1530          * in the future we should be able to conservatively scan only:
1531          * *) the cpu registers
1532          * *) the unmanaged stack frames
1533          * *) the _last_ managed stack frame
1534          * *) pointers slots in managed frames
1535          */
1536         scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1537 }
1538
1539 static void
1540 unpin_objects_from_queue (SgenGrayQueue *queue)
1541 {
1542         for (;;) {
1543                 char *addr;
1544                 GRAY_OBJECT_DEQUEUE (queue, addr);
1545                 if (!addr)
1546                         break;
1547                 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1548                 SGEN_UNPIN_OBJECT (addr);
1549         }
1550 }
1551
1552 typedef struct {
1553         CopyOrMarkObjectFunc func;
1554         GrayQueue *queue;
1555 } UserCopyOrMarkData;
1556
1557 static MonoNativeTlsKey user_copy_or_mark_key;
1558
1559 static void
1560 init_user_copy_or_mark_key (void)
1561 {
1562         mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1563 }
1564
1565 static void
1566 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1567 {
1568         mono_native_tls_set_value (user_copy_or_mark_key, data);
1569 }
1570
1571 static void
1572 single_arg_user_copy_or_mark (void **obj)
1573 {
1574         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1575
1576         data->func (obj, data->queue);
1577 }
1578
1579 /*
1580  * The memory area from start_root to end_root contains pointers to objects.
1581  * Their position is precisely described by @desc (this means that the pointer
1582  * can be either NULL or the pointer to the start of an object).
1583  * This functions copies them to to_space updates them.
1584  *
1585  * This function is not thread-safe!
1586  */
1587 static void
1588 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1589 {
1590         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1591         SgenGrayQueue *queue = ctx.queue;
1592
1593         switch (desc & ROOT_DESC_TYPE_MASK) {
1594         case ROOT_DESC_BITMAP:
1595                 desc >>= ROOT_DESC_TYPE_SHIFT;
1596                 while (desc) {
1597                         if ((desc & 1) && *start_root) {
1598                                 copy_func (start_root, queue);
1599                                 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1600                                 sgen_drain_gray_stack (-1, ctx);
1601                         }
1602                         desc >>= 1;
1603                         start_root++;
1604                 }
1605                 return;
1606         case ROOT_DESC_COMPLEX: {
1607                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1608                 int bwords = (*bitmap_data) - 1;
1609                 void **start_run = start_root;
1610                 bitmap_data++;
1611                 while (bwords-- > 0) {
1612                         gsize bmap = *bitmap_data++;
1613                         void **objptr = start_run;
1614                         while (bmap) {
1615                                 if ((bmap & 1) && *objptr) {
1616                                         copy_func (objptr, queue);
1617                                         SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1618                                         sgen_drain_gray_stack (-1, ctx);
1619                                 }
1620                                 bmap >>= 1;
1621                                 ++objptr;
1622                         }
1623                         start_run += GC_BITS_PER_WORD;
1624                 }
1625                 break;
1626         }
1627         case ROOT_DESC_USER: {
1628                 UserCopyOrMarkData data = { copy_func, queue };
1629                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1630                 set_user_copy_or_mark_data (&data);
1631                 marker (start_root, single_arg_user_copy_or_mark);
1632                 set_user_copy_or_mark_data (NULL);
1633                 break;
1634         }
1635         case ROOT_DESC_RUN_LEN:
1636                 g_assert_not_reached ();
1637         default:
1638                 g_assert_not_reached ();
1639         }
1640 }
1641
1642 static void
1643 reset_heap_boundaries (void)
1644 {
1645         lowest_heap_address = ~(mword)0;
1646         highest_heap_address = 0;
1647 }
1648
1649 void
1650 sgen_update_heap_boundaries (mword low, mword high)
1651 {
1652         mword old;
1653
1654         do {
1655                 old = lowest_heap_address;
1656                 if (low >= old)
1657                         break;
1658         } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1659
1660         do {
1661                 old = highest_heap_address;
1662                 if (high <= old)
1663                         break;
1664         } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1665 }
1666
1667 /*
1668  * Allocate and setup the data structures needed to be able to allocate objects
1669  * in the nursery. The nursery is stored in nursery_section.
1670  */
1671 static void
1672 alloc_nursery (void)
1673 {
1674         GCMemSection *section;
1675         char *data;
1676         int scan_starts;
1677         int alloc_size;
1678
1679         if (nursery_section)
1680                 return;
1681         SGEN_LOG (2, "Allocating nursery size: %lu", (unsigned long)sgen_nursery_size);
1682         /* later we will alloc a larger area for the nursery but only activate
1683          * what we need. The rest will be used as expansion if we have too many pinned
1684          * objects in the existing nursery.
1685          */
1686         /* FIXME: handle OOM */
1687         section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1688
1689         alloc_size = sgen_nursery_size;
1690
1691         /* If there isn't enough space even for the nursery we should simply abort. */
1692         g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1693
1694 #ifdef SGEN_ALIGN_NURSERY
1695         data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1696 #else
1697         data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1698 #endif
1699         sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1700         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 ());
1701         section->data = section->next_data = data;
1702         section->size = alloc_size;
1703         section->end_data = data + sgen_nursery_size;
1704         scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1705         section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1706         section->num_scan_start = scan_starts;
1707
1708         nursery_section = section;
1709
1710         sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1711 }
1712
1713 void*
1714 mono_gc_get_nursery (int *shift_bits, size_t *size)
1715 {
1716         *size = sgen_nursery_size;
1717 #ifdef SGEN_ALIGN_NURSERY
1718         *shift_bits = DEFAULT_NURSERY_BITS;
1719 #else
1720         *shift_bits = -1;
1721 #endif
1722         return sgen_get_nursery_start ();
1723 }
1724
1725 void
1726 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1727 {
1728         SgenThreadInfo *info = mono_thread_info_current ();
1729
1730         /* Could be called from sgen_thread_unregister () with a NULL info */
1731         if (domain) {
1732                 g_assert (info);
1733                 info->stopped_domain = domain;
1734         }
1735 }
1736
1737 gboolean
1738 mono_gc_precise_stack_mark_enabled (void)
1739 {
1740         return !conservative_stack_mark;
1741 }
1742
1743 FILE *
1744 mono_gc_get_logfile (void)
1745 {
1746         return gc_debug_file;
1747 }
1748
1749 static void
1750 report_finalizer_roots_list (FinalizeReadyEntry *list)
1751 {
1752         GCRootReport report;
1753         FinalizeReadyEntry *fin;
1754
1755         report.count = 0;
1756         for (fin = list; fin; fin = fin->next) {
1757                 if (!fin->object)
1758                         continue;
1759                 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1760         }
1761         notify_gc_roots (&report);
1762 }
1763
1764 static void
1765 report_finalizer_roots (void)
1766 {
1767         report_finalizer_roots_list (fin_ready_list);
1768         report_finalizer_roots_list (critical_fin_list);
1769 }
1770
1771 static GCRootReport *root_report;
1772
1773 static void
1774 single_arg_report_root (void **obj)
1775 {
1776         if (*obj)
1777                 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1778 }
1779
1780 static void
1781 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1782 {
1783         switch (desc & ROOT_DESC_TYPE_MASK) {
1784         case ROOT_DESC_BITMAP:
1785                 desc >>= ROOT_DESC_TYPE_SHIFT;
1786                 while (desc) {
1787                         if ((desc & 1) && *start_root) {
1788                                 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1789                         }
1790                         desc >>= 1;
1791                         start_root++;
1792                 }
1793                 return;
1794         case ROOT_DESC_COMPLEX: {
1795                 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1796                 int bwords = (*bitmap_data) - 1;
1797                 void **start_run = start_root;
1798                 bitmap_data++;
1799                 while (bwords-- > 0) {
1800                         gsize bmap = *bitmap_data++;
1801                         void **objptr = start_run;
1802                         while (bmap) {
1803                                 if ((bmap & 1) && *objptr) {
1804                                         add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1805                                 }
1806                                 bmap >>= 1;
1807                                 ++objptr;
1808                         }
1809                         start_run += GC_BITS_PER_WORD;
1810                 }
1811                 break;
1812         }
1813         case ROOT_DESC_USER: {
1814                 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1815                 root_report = report;
1816                 marker (start_root, single_arg_report_root);
1817                 break;
1818         }
1819         case ROOT_DESC_RUN_LEN:
1820                 g_assert_not_reached ();
1821         default:
1822                 g_assert_not_reached ();
1823         }
1824 }
1825
1826 static void
1827 report_registered_roots_by_type (int root_type)
1828 {
1829         GCRootReport report;
1830         void **start_root;
1831         RootRecord *root;
1832         report.count = 0;
1833         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1834                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1835                 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1836         } SGEN_HASH_TABLE_FOREACH_END;
1837         notify_gc_roots (&report);
1838 }
1839
1840 static void
1841 report_registered_roots (void)
1842 {
1843         report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1844         report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1845 }
1846
1847 static void
1848 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1849 {
1850         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1851         SgenGrayQueue *queue = ctx.queue;
1852         FinalizeReadyEntry *fin;
1853
1854         for (fin = list; fin; fin = fin->next) {
1855                 if (!fin->object)
1856                         continue;
1857                 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1858                 copy_func (&fin->object, queue);
1859         }
1860 }
1861
1862 static const char*
1863 generation_name (int generation)
1864 {
1865         switch (generation) {
1866         case GENERATION_NURSERY: return "nursery";
1867         case GENERATION_OLD: return "old";
1868         default: g_assert_not_reached ();
1869         }
1870 }
1871
1872 const char*
1873 sgen_generation_name (int generation)
1874 {
1875         return generation_name (generation);
1876 }
1877
1878 SgenObjectOperations *
1879 sgen_get_current_object_ops (void){
1880         return &current_object_ops;
1881 }
1882
1883
1884 static void
1885 finish_gray_stack (int generation, GrayQueue *queue)
1886 {
1887         TV_DECLARE (atv);
1888         TV_DECLARE (btv);
1889         int done_with_ephemerons, ephemeron_rounds = 0;
1890         CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1891         ScanObjectFunc scan_func = current_object_ops.scan_object;
1892         ScanCopyContext ctx = { scan_func, copy_func, queue };
1893         char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1894         char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1895
1896         /*
1897          * We copied all the reachable objects. Now it's the time to copy
1898          * the objects that were not referenced by the roots, but by the copied objects.
1899          * we built a stack of objects pointed to by gray_start: they are
1900          * additional roots and we may add more items as we go.
1901          * We loop until gray_start == gray_objects which means no more objects have
1902          * been added. Note this is iterative: no recursion is involved.
1903          * We need to walk the LO list as well in search of marked big objects
1904          * (use a flag since this is needed only on major collections). We need to loop
1905          * here as well, so keep a counter of marked LO (increasing it in copy_object).
1906          *   To achieve better cache locality and cache usage, we drain the gray stack
1907          * frequently, after each object is copied, and just finish the work here.
1908          */
1909         sgen_drain_gray_stack (-1, ctx);
1910         TV_GETTIME (atv);
1911         SGEN_LOG (2, "%s generation done", generation_name (generation));
1912
1913         /*
1914         Reset bridge data, we might have lingering data from a previous collection if this is a major
1915         collection trigged by minor overflow.
1916
1917         We must reset the gathered bridges since their original block might be evacuated due to major
1918         fragmentation in the meanwhile and the bridge code should not have to deal with that.
1919         */
1920         if (sgen_need_bridge_processing ())
1921                 sgen_bridge_reset_data ();
1922
1923         /*
1924          * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1925          * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1926          * objects that are in fact reachable.
1927          */
1928         done_with_ephemerons = 0;
1929         do {
1930                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1931                 sgen_drain_gray_stack (-1, ctx);
1932                 ++ephemeron_rounds;
1933         } while (!done_with_ephemerons);
1934
1935         sgen_scan_togglerefs (start_addr, end_addr, ctx);
1936
1937         if (sgen_need_bridge_processing ()) {
1938                 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1939                 sgen_drain_gray_stack (-1, ctx);
1940                 sgen_collect_bridge_objects (generation, ctx);
1941                 if (generation == GENERATION_OLD)
1942                         sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1943
1944                 /*
1945                 Do the first bridge step here, as the collector liveness state will become useless after that.
1946
1947                 An important optimization is to only proccess the possibly dead part of the object graph and skip
1948                 over all live objects as we transitively know everything they point must be alive too.
1949
1950                 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1951
1952                 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1953                 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1954                 be a big deal.
1955                 */
1956                 sgen_bridge_processing_stw_step ();
1957         }
1958
1959         /*
1960         Make sure we drain the gray stack before processing disappearing links and finalizers.
1961         If we don't make sure it is empty we might wrongly see a live object as dead.
1962         */
1963         sgen_drain_gray_stack (-1, ctx);
1964
1965         /*
1966         We must clear weak links that don't track resurrection before processing object ready for
1967         finalization so they can be cleared before that.
1968         */
1969         sgen_null_link_in_range (generation, TRUE, ctx);
1970         if (generation == GENERATION_OLD)
1971                 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1972
1973
1974         /* walk the finalization queue and move also the objects that need to be
1975          * finalized: use the finalized objects as new roots so the objects they depend
1976          * on are also not reclaimed. As with the roots above, only objects in the nursery
1977          * are marked/copied.
1978          */
1979         sgen_finalize_in_range (generation, ctx);
1980         if (generation == GENERATION_OLD)
1981                 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1982         /* drain the new stack that might have been created */
1983         SGEN_LOG (6, "Precise scan of gray area post fin");
1984         sgen_drain_gray_stack (-1, ctx);
1985
1986         /*
1987          * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1988          */
1989         done_with_ephemerons = 0;
1990         do {
1991                 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1992                 sgen_drain_gray_stack (-1, ctx);
1993                 ++ephemeron_rounds;
1994         } while (!done_with_ephemerons);
1995
1996         /*
1997          * Clear ephemeron pairs with unreachable keys.
1998          * We pass the copy func so we can figure out if an array was promoted or not.
1999          */
2000         clear_unreachable_ephemerons (ctx);
2001
2002         TV_GETTIME (btv);
2003         SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
2004
2005         /*
2006          * handle disappearing links
2007          * Note we do this after checking the finalization queue because if an object
2008          * survives (at least long enough to be finalized) we don't clear the link.
2009          * This also deals with a possible issue with the monitor reclamation: with the Boehm
2010          * GC a finalized object my lose the monitor because it is cleared before the finalizer is
2011          * called.
2012          */
2013         g_assert (sgen_gray_object_queue_is_empty (queue));
2014         for (;;) {
2015                 sgen_null_link_in_range (generation, FALSE, ctx);
2016                 if (generation == GENERATION_OLD)
2017                         sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
2018                 if (sgen_gray_object_queue_is_empty (queue))
2019                         break;
2020                 sgen_drain_gray_stack (-1, ctx);
2021         }
2022
2023         g_assert (sgen_gray_object_queue_is_empty (queue));
2024 }
2025
2026 void
2027 sgen_check_section_scan_starts (GCMemSection *section)
2028 {
2029         int i;
2030         for (i = 0; i < section->num_scan_start; ++i) {
2031                 if (section->scan_starts [i]) {
2032                         guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2033                         g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2034                 }
2035         }
2036 }
2037
2038 static void
2039 check_scan_starts (void)
2040 {
2041         if (!do_scan_starts_check)
2042                 return;
2043         sgen_check_section_scan_starts (nursery_section);
2044         major_collector.check_scan_starts ();
2045 }
2046
2047 static void
2048 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
2049 {
2050         void **start_root;
2051         RootRecord *root;
2052         SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2053                 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
2054                 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
2055         } SGEN_HASH_TABLE_FOREACH_END;
2056 }
2057
2058 void
2059 sgen_dump_occupied (char *start, char *end, char *section_start)
2060 {
2061         fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2062 }
2063
2064 void
2065 sgen_dump_section (GCMemSection *section, const char *type)
2066 {
2067         char *start = section->data;
2068         char *end = section->data + section->size;
2069         char *occ_start = NULL;
2070         GCVTable *vt;
2071         char *old_start = NULL; /* just for debugging */
2072
2073         fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2074
2075         while (start < end) {
2076                 guint size;
2077                 MonoClass *class;
2078
2079                 if (!*(void**)start) {
2080                         if (occ_start) {
2081                                 sgen_dump_occupied (occ_start, start, section->data);
2082                                 occ_start = NULL;
2083                         }
2084                         start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2085                         continue;
2086                 }
2087                 g_assert (start < section->next_data);
2088
2089                 if (!occ_start)
2090                         occ_start = start;
2091
2092                 vt = (GCVTable*)LOAD_VTABLE (start);
2093                 class = vt->klass;
2094
2095                 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2096
2097                 /*
2098                 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2099                                 start - section->data,
2100                                 vt->klass->name_space, vt->klass->name,
2101                                 size);
2102                 */
2103
2104                 old_start = start;
2105                 start += size;
2106         }
2107         if (occ_start)
2108                 sgen_dump_occupied (occ_start, start, section->data);
2109
2110         fprintf (heap_dump_file, "</section>\n");
2111 }
2112
2113 static void
2114 dump_object (MonoObject *obj, gboolean dump_location)
2115 {
2116         static char class_name [1024];
2117
2118         MonoClass *class = mono_object_class (obj);
2119         int i, j;
2120
2121         /*
2122          * Python's XML parser is too stupid to parse angle brackets
2123          * in strings, so we just ignore them;
2124          */
2125         i = j = 0;
2126         while (class->name [i] && j < sizeof (class_name) - 1) {
2127                 if (!strchr ("<>\"", class->name [i]))
2128                         class_name [j++] = class->name [i];
2129                 ++i;
2130         }
2131         g_assert (j < sizeof (class_name));
2132         class_name [j] = 0;
2133
2134         fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2135                         class->name_space, class_name,
2136                         safe_object_get_size (obj));
2137         if (dump_location) {
2138                 const char *location;
2139                 if (ptr_in_nursery (obj))
2140                         location = "nursery";
2141                 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2142                         location = "major";
2143                 else
2144                         location = "LOS";
2145                 fprintf (heap_dump_file, " location=\"%s\"", location);
2146         }
2147         fprintf (heap_dump_file, "/>\n");
2148 }
2149
2150 static void
2151 dump_heap (const char *type, int num, const char *reason)
2152 {
2153         ObjectList *list;
2154         LOSObject *bigobj;
2155
2156         fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2157         if (reason)
2158                 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2159         fprintf (heap_dump_file, ">\n");
2160         fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2161         sgen_dump_internal_mem_usage (heap_dump_file);
2162         fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2163         /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2164         fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2165
2166         fprintf (heap_dump_file, "<pinned-objects>\n");
2167         for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2168                 dump_object (list->obj, TRUE);
2169         fprintf (heap_dump_file, "</pinned-objects>\n");
2170
2171         sgen_dump_section (nursery_section, "nursery");
2172
2173         major_collector.dump_heap (heap_dump_file);
2174
2175         fprintf (heap_dump_file, "<los>\n");
2176         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2177                 dump_object ((MonoObject*)bigobj->data, FALSE);
2178         fprintf (heap_dump_file, "</los>\n");
2179
2180         fprintf (heap_dump_file, "</collection>\n");
2181 }
2182
2183 void
2184 sgen_register_moved_object (void *obj, void *destination)
2185 {
2186         g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2187
2188         /* FIXME: handle this for parallel collector */
2189         g_assert (!sgen_collection_is_parallel ());
2190
2191         if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2192                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2193                 moved_objects_idx = 0;
2194         }
2195         moved_objects [moved_objects_idx++] = obj;
2196         moved_objects [moved_objects_idx++] = destination;
2197 }
2198
2199 static void
2200 init_stats (void)
2201 {
2202         static gboolean inited = FALSE;
2203
2204         if (inited)
2205                 return;
2206
2207         mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2208         mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2209         mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2210         mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2211         mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2212         mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2213         mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2214         mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2215
2216         mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2217         mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2218         mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2219         mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2220         mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2221         mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2222         mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2223         mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2224         mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2225         mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2226         mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2227         mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2228         mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2229
2230         mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2231
2232 #ifdef HEAVY_STATISTICS
2233         mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
2234         mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2235         mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2236         mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2237         mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2238         mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
2239         mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2240         mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2241         mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2242
2243         mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2244         mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2245
2246         mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2247         mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2248         mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2249         mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2250
2251         mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2252         mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2253
2254         mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2255
2256         mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2257         mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2258         mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2259         mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2260
2261         sgen_nursery_allocator_init_heavy_stats ();
2262         sgen_alloc_init_heavy_stats ();
2263 #endif
2264
2265         inited = TRUE;
2266 }
2267
2268
2269 static void
2270 reset_pinned_from_failed_allocation (void)
2271 {
2272         bytes_pinned_from_failed_allocation = 0;
2273 }
2274
2275 void
2276 sgen_set_pinned_from_failed_allocation (mword objsize)
2277 {
2278         bytes_pinned_from_failed_allocation += objsize;
2279 }
2280
2281 gboolean
2282 sgen_collection_is_parallel (void)
2283 {
2284         switch (current_collection_generation) {
2285         case GENERATION_NURSERY:
2286                 return nursery_collection_is_parallel;
2287         case GENERATION_OLD:
2288                 return major_collector.is_parallel;
2289         default:
2290                 g_error ("Invalid current generation %d", current_collection_generation);
2291         }
2292 }
2293
2294 gboolean
2295 sgen_collection_is_concurrent (void)
2296 {
2297         switch (current_collection_generation) {
2298         case GENERATION_NURSERY:
2299                 return FALSE;
2300         case GENERATION_OLD:
2301                 return concurrent_collection_in_progress;
2302         default:
2303                 g_error ("Invalid current generation %d", current_collection_generation);
2304         }
2305 }
2306
2307 gboolean
2308 sgen_concurrent_collection_in_progress (void)
2309 {
2310         return concurrent_collection_in_progress;
2311 }
2312
2313 typedef struct
2314 {
2315         char *heap_start;
2316         char *heap_end;
2317 } FinishRememberedSetScanJobData;
2318
2319 static void
2320 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2321 {
2322         FinishRememberedSetScanJobData *job_data = job_data_untyped;
2323
2324         remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2325         sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2326 }
2327
2328 typedef struct
2329 {
2330         CopyOrMarkObjectFunc copy_or_mark_func;
2331         ScanObjectFunc scan_func;
2332         char *heap_start;
2333         char *heap_end;
2334         int root_type;
2335 } ScanFromRegisteredRootsJobData;
2336
2337 static void
2338 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2339 {
2340         ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2341         ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2342                 sgen_workers_get_job_gray_queue (worker_data) };
2343
2344         scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2345         sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2346 }
2347
2348 typedef struct
2349 {
2350         char *heap_start;
2351         char *heap_end;
2352 } ScanThreadDataJobData;
2353
2354 static void
2355 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2356 {
2357         ScanThreadDataJobData *job_data = job_data_untyped;
2358
2359         scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2360                         sgen_workers_get_job_gray_queue (worker_data));
2361         sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2362 }
2363
2364 typedef struct
2365 {
2366         FinalizeReadyEntry *list;
2367 } ScanFinalizerEntriesJobData;
2368
2369 static void
2370 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2371 {
2372         ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2373         ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2374
2375         scan_finalizer_entries (job_data->list, ctx);
2376         sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2377 }
2378
2379 static void
2380 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2381 {
2382         g_assert (concurrent_collection_in_progress);
2383         major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2384 }
2385
2386 static void
2387 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2388 {
2389         g_assert (concurrent_collection_in_progress);
2390         sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2391 }
2392
2393 static void
2394 verify_scan_starts (char *start, char *end)
2395 {
2396         int i;
2397
2398         for (i = 0; i < nursery_section->num_scan_start; ++i) {
2399                 char *addr = nursery_section->scan_starts [i];
2400                 if (addr > start && addr < end)
2401                         SGEN_LOG (1, "NFC-BAD SCAN START [%d] %p for obj [%p %p]", i, addr, start, end);
2402         }
2403 }
2404
2405 static void
2406 verify_nursery (void)
2407 {
2408         char *start, *end, *cur, *hole_start;
2409
2410         if (!do_verify_nursery)
2411                 return;
2412
2413         /*This cleans up unused fragments */
2414         sgen_nursery_allocator_prepare_for_pinning ();
2415
2416         hole_start = start = cur = sgen_get_nursery_start ();
2417         end = sgen_get_nursery_end ();
2418
2419         while (cur < end) {
2420                 size_t ss, size;
2421
2422                 if (!*(void**)cur) {
2423                         cur += sizeof (void*);
2424                         continue;
2425                 }
2426
2427                 if (object_is_forwarded (cur))
2428                         SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2429                 else if (object_is_pinned (cur))
2430                         SGEN_LOG (1, "PINNED OBJ %p", cur);
2431
2432                 ss = safe_object_get_size ((MonoObject*)cur);
2433                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2434                 verify_scan_starts (cur, cur + size);
2435                 if (do_dump_nursery_content) {
2436                         if (cur > hole_start)
2437                                 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2438                         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 ());
2439                 }
2440                 cur += size;
2441                 hole_start = cur;
2442         }
2443 }
2444
2445 /*
2446  * Checks that no objects in the nursery are fowarded or pinned.  This
2447  * is a precondition to restarting the mutator while doing a
2448  * concurrent collection.  Note that we don't clear fragments because
2449  * we depend on that having happened earlier.
2450  */
2451 static void
2452 check_nursery_is_clean (void)
2453 {
2454         char *start, *end, *cur;
2455
2456         start = cur = sgen_get_nursery_start ();
2457         end = sgen_get_nursery_end ();
2458
2459         while (cur < end) {
2460                 size_t ss, size;
2461
2462                 if (!*(void**)cur) {
2463                         cur += sizeof (void*);
2464                         continue;
2465                 }
2466
2467                 g_assert (!object_is_forwarded (cur));
2468                 g_assert (!object_is_pinned (cur));
2469
2470                 ss = safe_object_get_size ((MonoObject*)cur);
2471                 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2472                 verify_scan_starts (cur, cur + size);
2473
2474                 cur += size;
2475         }
2476 }
2477
2478 static void
2479 init_gray_queue (void)
2480 {
2481         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2482                 sgen_workers_init_distribute_gray_queue ();
2483                 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2484                                 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2485         } else {
2486                 sgen_gray_object_queue_init (&gray_queue, NULL);
2487         }
2488 }
2489
2490 static void
2491 pin_stage_object_callback (char *obj, size_t size, void *data)
2492 {
2493         sgen_pin_stage_ptr (obj);
2494         /* FIXME: do pin stats if enabled */
2495 }
2496
2497 /*
2498  * Collect objects in the nursery.  Returns whether to trigger a major
2499  * collection.
2500  */
2501 static gboolean
2502 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2503 {
2504         gboolean needs_major;
2505         size_t max_garbage_amount;
2506         char *nursery_next;
2507         FinishRememberedSetScanJobData *frssjd;
2508         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2509         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2510         ScanThreadDataJobData *stdjd;
2511         mword fragment_total;
2512         ScanCopyContext ctx;
2513         TV_DECLARE (all_atv);
2514         TV_DECLARE (all_btv);
2515         TV_DECLARE (atv);
2516         TV_DECLARE (btv);
2517
2518         if (disable_minor_collections)
2519                 return TRUE;
2520
2521         MONO_GC_BEGIN (GENERATION_NURSERY);
2522         binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2523
2524         verify_nursery ();
2525
2526 #ifndef DISABLE_PERFCOUNTERS
2527         mono_perfcounters->gc_collections0++;
2528 #endif
2529
2530         current_collection_generation = GENERATION_NURSERY;
2531         if (sgen_collection_is_parallel ())
2532                 current_object_ops = sgen_minor_collector.parallel_ops;
2533         else
2534                 current_object_ops = sgen_minor_collector.serial_ops;
2535
2536         reset_pinned_from_failed_allocation ();
2537
2538         check_scan_starts ();
2539
2540         sgen_nursery_alloc_prepare_for_minor ();
2541
2542         degraded_mode = 0;
2543         objects_pinned = 0;
2544         nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2545         /* FIXME: optimize later to use the higher address where an object can be present */
2546         nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2547
2548         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 ()));
2549         max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2550         g_assert (nursery_section->size >= max_garbage_amount);
2551
2552         /* world must be stopped already */
2553         TV_GETTIME (all_atv);
2554         atv = all_atv;
2555
2556         TV_GETTIME (btv);
2557         time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2558
2559         if (xdomain_checks) {
2560                 sgen_clear_nursery_fragments ();
2561                 check_for_xdomain_refs ();
2562         }
2563
2564         nursery_section->next_data = nursery_next;
2565
2566         major_collector.start_nursery_collection ();
2567
2568         sgen_memgov_minor_collection_start ();
2569
2570         init_gray_queue ();
2571
2572         stat_minor_gcs++;
2573         gc_stats.minor_gc_count ++;
2574
2575         MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2576
2577         sgen_process_fin_stage_entries ();
2578         sgen_process_dislink_stage_entries ();
2579
2580         MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2581
2582         /* pin from pinned handles */
2583         sgen_init_pinning ();
2584         mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2585         pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2586         /* pin cemented objects */
2587         sgen_cement_iterate (pin_stage_object_callback, NULL);
2588         /* identify pinned objects */
2589         sgen_optimize_pin_queue (0);
2590         sgen_pinning_setup_section (nursery_section);
2591         ctx.scan_func = NULL;
2592         ctx.copy_func = NULL;
2593         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2594         sgen_pin_objects_in_section (nursery_section, ctx);
2595         sgen_pinning_trim_queue_to_section (nursery_section);
2596
2597         TV_GETTIME (atv);
2598         time_minor_pinning += TV_ELAPSED (btv, atv);
2599         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2600         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2601
2602         MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2603
2604         if (whole_heap_check_before_collection) {
2605                 sgen_clear_nursery_fragments ();
2606                 sgen_check_whole_heap (finish_up_concurrent_mark);
2607         }
2608         if (consistency_check_at_minor_collection)
2609                 sgen_check_consistency ();
2610
2611         sgen_workers_start_all_workers ();
2612         sgen_workers_start_marking ();
2613
2614         frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2615         frssjd->heap_start = sgen_get_nursery_start ();
2616         frssjd->heap_end = nursery_next;
2617         sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2618
2619         /* we don't have complete write barrier yet, so we scan all the old generation sections */
2620         TV_GETTIME (btv);
2621         time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2622         SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2623
2624         MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2625
2626         if (!sgen_collection_is_parallel ()) {
2627                 ctx.scan_func = current_object_ops.scan_object;
2628                 ctx.copy_func = NULL;
2629                 ctx.queue = &gray_queue;
2630                 sgen_drain_gray_stack (-1, ctx);
2631         }
2632
2633         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2634                 report_registered_roots ();
2635         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2636                 report_finalizer_roots ();
2637         TV_GETTIME (atv);
2638         time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2639
2640         MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2641
2642         /* registered roots, this includes static fields */
2643         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2644         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2645         scrrjd_normal->scan_func = current_object_ops.scan_object;
2646         scrrjd_normal->heap_start = sgen_get_nursery_start ();
2647         scrrjd_normal->heap_end = nursery_next;
2648         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2649         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2650
2651         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2652         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2653         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2654         scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2655         scrrjd_wbarrier->heap_end = nursery_next;
2656         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2657         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2658
2659         TV_GETTIME (btv);
2660         time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2661
2662         MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2663
2664         /* thread data */
2665         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2666         stdjd->heap_start = sgen_get_nursery_start ();
2667         stdjd->heap_end = nursery_next;
2668         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2669
2670         TV_GETTIME (atv);
2671         time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2672         btv = atv;
2673
2674         MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2675
2676         g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2677
2678         if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2679                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2680
2681         /* Scan the list of objects ready for finalization. If */
2682         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2683         sfejd_fin_ready->list = fin_ready_list;
2684         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2685
2686         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2687         sfejd_critical_fin->list = critical_fin_list;
2688         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2689
2690         MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2691
2692         finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2693         TV_GETTIME (atv);
2694         time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2695         mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2696
2697         MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2698
2699         /*
2700          * The (single-threaded) finalization code might have done
2701          * some copying/marking so we can only reset the GC thread's
2702          * worker data here instead of earlier when we joined the
2703          * workers.
2704          */
2705         sgen_workers_reset_data ();
2706
2707         if (objects_pinned) {
2708                 sgen_optimize_pin_queue (0);
2709                 sgen_pinning_setup_section (nursery_section);
2710         }
2711
2712         /* walk the pin_queue, build up the fragment list of free memory, unmark
2713          * pinned objects as we go, memzero() the empty fragments so they are ready for the
2714          * next allocations.
2715          */
2716         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2717         fragment_total = sgen_build_nursery_fragments (nursery_section,
2718                         nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2719                         unpin_queue);
2720         if (!fragment_total)
2721                 degraded_mode = 1;
2722
2723         /* Clear TLABs for all threads */
2724         sgen_clear_tlabs ();
2725
2726         mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2727         TV_GETTIME (btv);
2728         time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2729         SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2730
2731         if (consistency_check_at_minor_collection)
2732                 sgen_check_major_refs ();
2733
2734         major_collector.finish_nursery_collection ();
2735
2736         TV_GETTIME (all_btv);
2737         gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2738
2739         if (heap_dump_file)
2740                 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2741
2742         /* prepare the pin queue for the next collection */
2743         sgen_finish_pinning ();
2744         if (fin_ready_list || critical_fin_list) {
2745                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2746                 mono_gc_finalize_notify ();
2747         }
2748         sgen_pin_stats_reset ();
2749         /* clear cemented hash */
2750         sgen_cement_clear_below_threshold ();
2751
2752         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2753
2754         remset.finish_minor_collection ();
2755
2756         check_scan_starts ();
2757
2758         binary_protocol_flush_buffers (FALSE);
2759
2760         sgen_memgov_minor_collection_end ();
2761
2762         /*objects are late pinned because of lack of memory, so a major is a good call*/
2763         needs_major = objects_pinned > 0;
2764         current_collection_generation = -1;
2765         objects_pinned = 0;
2766
2767         MONO_GC_END (GENERATION_NURSERY);
2768         binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2769
2770         if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2771                 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2772
2773         return needs_major;
2774 }
2775
2776 static void
2777 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2778 {
2779         ctx->scan_func (obj, ctx->queue);
2780 }
2781
2782 static void
2783 scan_nursery_objects (ScanCopyContext ctx)
2784 {
2785         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2786                         (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2787 }
2788
2789 static void
2790 major_copy_or_mark_from_roots (int *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2791 {
2792         LOSObject *bigobj;
2793         TV_DECLARE (atv);
2794         TV_DECLARE (btv);
2795         /* FIXME: only use these values for the precise scan
2796          * note that to_space pointers should be excluded anyway...
2797          */
2798         char *heap_start = NULL;
2799         char *heap_end = (char*)-1;
2800         gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2801         GCRootReport root_report = { 0 };
2802         ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2803         ScanThreadDataJobData *stdjd;
2804         ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2805         ScanCopyContext ctx;
2806
2807         if (concurrent_collection_in_progress) {
2808                 /*This cleans up unused fragments */
2809                 sgen_nursery_allocator_prepare_for_pinning ();
2810
2811                 if (do_concurrent_checks)
2812                         check_nursery_is_clean ();
2813         } else {
2814                 /* The concurrent collector doesn't touch the nursery. */
2815                 sgen_nursery_alloc_prepare_for_major ();
2816         }
2817
2818         init_gray_queue ();
2819
2820         TV_GETTIME (atv);
2821
2822         /* Pinning depends on this */
2823         sgen_clear_nursery_fragments ();
2824
2825         if (whole_heap_check_before_collection)
2826                 sgen_check_whole_heap (finish_up_concurrent_mark);
2827
2828         TV_GETTIME (btv);
2829         time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2830
2831         if (!sgen_collection_is_concurrent ())
2832                 nursery_section->next_data = sgen_get_nursery_end ();
2833         /* we should also coalesce scanning from sections close to each other
2834          * and deal with pointers outside of the sections later.
2835          */
2836
2837         objects_pinned = 0;
2838         *major_collector.have_swept = FALSE;
2839
2840         if (xdomain_checks) {
2841                 sgen_clear_nursery_fragments ();
2842                 check_for_xdomain_refs ();
2843         }
2844
2845         if (!concurrent_collection_in_progress) {
2846                 /* Remsets are not useful for a major collection */
2847                 remset.prepare_for_major_collection ();
2848         }
2849
2850         sgen_process_fin_stage_entries ();
2851         sgen_process_dislink_stage_entries ();
2852
2853         TV_GETTIME (atv);
2854         sgen_init_pinning ();
2855         SGEN_LOG (6, "Collecting pinned addresses");
2856         pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2857
2858         if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2859                 if (major_collector.is_concurrent) {
2860                         /*
2861                          * The concurrent major collector cannot evict
2862                          * yet, so we need to pin cemented objects to
2863                          * not break some asserts.
2864                          *
2865                          * FIXME: We could evict now!
2866                          */
2867                         sgen_cement_iterate (pin_stage_object_callback, NULL);
2868                 }
2869
2870                 if (!concurrent_collection_in_progress)
2871                         sgen_cement_reset ();
2872         }
2873
2874         sgen_optimize_pin_queue (0);
2875
2876         /*
2877          * The concurrent collector doesn't move objects, neither on
2878          * the major heap nor in the nursery, so we can mark even
2879          * before pinning has finished.  For the non-concurrent
2880          * collector we start the workers after pinning.
2881          */
2882         if (concurrent_collection_in_progress) {
2883                 sgen_workers_start_all_workers ();
2884                 sgen_workers_start_marking ();
2885         }
2886
2887         /*
2888          * pin_queue now contains all candidate pointers, sorted and
2889          * uniqued.  We must do two passes now to figure out which
2890          * objects are pinned.
2891          *
2892          * The first is to find within the pin_queue the area for each
2893          * section.  This requires that the pin_queue be sorted.  We
2894          * also process the LOS objects and pinned chunks here.
2895          *
2896          * The second, destructive, pass is to reduce the section
2897          * areas to pointers to the actually pinned objects.
2898          */
2899         SGEN_LOG (6, "Pinning from sections");
2900         /* first pass for the sections */
2901         sgen_find_section_pin_queue_start_end (nursery_section);
2902         major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2903         /* identify possible pointers to the insize of large objects */
2904         SGEN_LOG (6, "Pinning from large objects");
2905         for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2906                 int dummy;
2907                 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2908                         binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2909
2910 #ifdef ENABLE_DTRACE
2911                         if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2912                                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2913                                 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2914                         }
2915 #endif
2916
2917                         if (sgen_los_object_is_pinned (bigobj->data)) {
2918                                 g_assert (finish_up_concurrent_mark);
2919                                 continue;
2920                         }
2921                         sgen_los_pin_object (bigobj->data);
2922                         /* FIXME: only enqueue if object has references */
2923                         GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2924                         if (G_UNLIKELY (do_pin_stats))
2925                                 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2926                         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));
2927
2928                         if (profile_roots)
2929                                 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2930                 }
2931         }
2932         if (profile_roots)
2933                 notify_gc_roots (&root_report);
2934         /* second pass for the sections */
2935         ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2936         ctx.copy_func = NULL;
2937         ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2938
2939         /*
2940          * Concurrent mark never follows references into the nursery.
2941          * In the start and finish pauses we must scan live nursery
2942          * objects, though.  We could simply scan all nursery objects,
2943          * but that would be conservative.  The easiest way is to do a
2944          * nursery collection, which copies all live nursery objects
2945          * (except pinned ones, with the simple nursery) to the major
2946          * heap.  Scanning the mod union table later will then scan
2947          * those promoted objects, provided they're reachable.  Pinned
2948          * objects in the nursery - which we can trivially find in the
2949          * pinning queue - are treated as roots in the mark pauses.
2950          *
2951          * The split nursery complicates the latter part because
2952          * non-pinned objects can survive in the nursery.  That's why
2953          * we need to do a full front-to-back scan of the nursery,
2954          * marking all objects.
2955          *
2956          * Non-concurrent mark evacuates from the nursery, so it's
2957          * sufficient to just scan pinned nursery objects.
2958          */
2959         if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2960                 scan_nursery_objects (ctx);
2961         } else {
2962                 sgen_pin_objects_in_section (nursery_section, ctx);
2963                 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2964                         sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2965         }
2966
2967         major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2968         if (old_next_pin_slot)
2969                 *old_next_pin_slot = sgen_get_pinned_count ();
2970
2971         TV_GETTIME (btv);
2972         time_major_pinning += TV_ELAPSED (atv, btv);
2973         SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2974         SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2975
2976         major_collector.init_to_space ();
2977
2978 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2979         main_gc_thread = mono_native_thread_self ();
2980 #endif
2981
2982         if (!concurrent_collection_in_progress && major_collector.is_parallel) {
2983                 sgen_workers_start_all_workers ();
2984                 sgen_workers_start_marking ();
2985         }
2986
2987         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2988                 report_registered_roots ();
2989         TV_GETTIME (atv);
2990         time_major_scan_pinned += TV_ELAPSED (btv, atv);
2991
2992         /* registered roots, this includes static fields */
2993         scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2994         scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2995         scrrjd_normal->scan_func = current_object_ops.scan_object;
2996         scrrjd_normal->heap_start = heap_start;
2997         scrrjd_normal->heap_end = heap_end;
2998         scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2999         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
3000
3001         scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3002         scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
3003         scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
3004         scrrjd_wbarrier->heap_start = heap_start;
3005         scrrjd_wbarrier->heap_end = heap_end;
3006         scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
3007         sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
3008
3009         TV_GETTIME (btv);
3010         time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
3011
3012         /* Threads */
3013         stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3014         stdjd->heap_start = heap_start;
3015         stdjd->heap_end = heap_end;
3016         sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
3017
3018         TV_GETTIME (atv);
3019         time_major_scan_thread_data += TV_ELAPSED (btv, atv);
3020
3021         TV_GETTIME (btv);
3022         time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
3023
3024         if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
3025                 report_finalizer_roots ();
3026
3027         /* scan the list of objects ready for finalization */
3028         sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3029         sfejd_fin_ready->list = fin_ready_list;
3030         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
3031
3032         sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
3033         sfejd_critical_fin->list = critical_fin_list;
3034         sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
3035
3036         if (scan_mod_union) {
3037                 g_assert (finish_up_concurrent_mark);
3038
3039                 /* Mod union card table */
3040                 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
3041                 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
3042         }
3043
3044         TV_GETTIME (atv);
3045         time_major_scan_finalized += TV_ELAPSED (btv, atv);
3046         SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
3047
3048         TV_GETTIME (btv);
3049         time_major_scan_big_objects += TV_ELAPSED (atv, btv);
3050
3051         if (concurrent_collection_in_progress) {
3052                 /* prepare the pin queue for the next collection */
3053                 sgen_finish_pinning ();
3054
3055                 sgen_pin_stats_reset ();
3056
3057                 if (do_concurrent_checks)
3058                         check_nursery_is_clean ();
3059         }
3060 }
3061
3062 static void
3063 major_start_collection (gboolean concurrent, int *old_next_pin_slot)
3064 {
3065         MONO_GC_BEGIN (GENERATION_OLD);
3066         binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
3067
3068         current_collection_generation = GENERATION_OLD;
3069 #ifndef DISABLE_PERFCOUNTERS
3070         mono_perfcounters->gc_collections1++;
3071 #endif
3072
3073         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3074
3075         if (concurrent) {
3076                 g_assert (major_collector.is_concurrent);
3077                 concurrent_collection_in_progress = TRUE;
3078
3079                 sgen_cement_concurrent_start ();
3080
3081                 current_object_ops = major_collector.major_concurrent_ops;
3082         } else {
3083                 current_object_ops = major_collector.major_ops;
3084         }
3085
3086         reset_pinned_from_failed_allocation ();
3087
3088         sgen_memgov_major_collection_start ();
3089
3090         //count_ref_nonref_objs ();
3091         //consistency_check ();
3092
3093         check_scan_starts ();
3094
3095         degraded_mode = 0;
3096         SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
3097         stat_major_gcs++;
3098         gc_stats.major_gc_count ++;
3099
3100         if (major_collector.start_major_collection)
3101                 major_collector.start_major_collection ();
3102
3103         major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
3104 }
3105
3106 static void
3107 wait_for_workers_to_finish (void)
3108 {
3109         if (concurrent_collection_in_progress || major_collector.is_parallel) {
3110                 gray_queue_redirect (&gray_queue);
3111                 sgen_workers_join ();
3112         }
3113
3114         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3115
3116 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3117         main_gc_thread = NULL;
3118 #endif
3119 }
3120
3121 static void
3122 major_finish_collection (const char *reason, int old_next_pin_slot, gboolean scan_mod_union)
3123 {
3124         LOSObject *bigobj, *prevbo;
3125         TV_DECLARE (atv);
3126         TV_DECLARE (btv);
3127
3128         TV_GETTIME (btv);
3129
3130         if (concurrent_collection_in_progress || major_collector.is_parallel)
3131                 wait_for_workers_to_finish ();
3132
3133         if (concurrent_collection_in_progress) {
3134                 current_object_ops = major_collector.major_concurrent_ops;
3135
3136                 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
3137                 wait_for_workers_to_finish ();
3138
3139                 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3140
3141                 if (do_concurrent_checks)
3142                         check_nursery_is_clean ();
3143         } else {
3144                 current_object_ops = major_collector.major_ops;
3145         }
3146
3147         /*
3148          * The workers have stopped so we need to finish gray queue
3149          * work that might result from finalization in the main GC
3150          * thread.  Redirection must therefore be turned off.
3151          */
3152         sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
3153         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3154
3155         /* all the objects in the heap */
3156         finish_gray_stack (GENERATION_OLD, &gray_queue);
3157         TV_GETTIME (atv);
3158         time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3159
3160         /*
3161          * The (single-threaded) finalization code might have done
3162          * some copying/marking so we can only reset the GC thread's
3163          * worker data here instead of earlier when we joined the
3164          * workers.
3165          */
3166         sgen_workers_reset_data ();
3167
3168         if (objects_pinned) {
3169                 g_assert (!concurrent_collection_in_progress);
3170
3171                 /*This is slow, but we just OOM'd*/
3172                 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3173                 sgen_optimize_pin_queue (0);
3174                 sgen_find_section_pin_queue_start_end (nursery_section);
3175                 objects_pinned = 0;
3176         }
3177
3178         reset_heap_boundaries ();
3179         sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3180
3181         if (check_mark_bits_after_major_collection)
3182                 sgen_check_major_heap_marked ();
3183
3184         MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
3185
3186         /* sweep the big objects list */
3187         prevbo = NULL;
3188         for (bigobj = los_object_list; bigobj;) {
3189                 g_assert (!object_is_pinned (bigobj->data));
3190                 if (sgen_los_object_is_pinned (bigobj->data)) {
3191                         sgen_los_unpin_object (bigobj->data);
3192                         sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
3193                 } else {
3194                         LOSObject *to_free;
3195                         /* not referenced anywhere, so we can free it */
3196                         if (prevbo)
3197                                 prevbo->next = bigobj->next;
3198                         else
3199                                 los_object_list = bigobj->next;
3200                         to_free = bigobj;
3201                         bigobj = bigobj->next;
3202                         sgen_los_free_object (to_free);
3203                         continue;
3204                 }
3205                 prevbo = bigobj;
3206                 bigobj = bigobj->next;
3207         }
3208
3209         TV_GETTIME (btv);
3210         time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3211
3212         sgen_los_sweep ();
3213
3214         TV_GETTIME (atv);
3215         time_major_los_sweep += TV_ELAPSED (btv, atv);
3216
3217         major_collector.sweep ();
3218
3219         MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
3220
3221         TV_GETTIME (btv);
3222         time_major_sweep += TV_ELAPSED (atv, btv);
3223
3224         if (!concurrent_collection_in_progress) {
3225                 /* walk the pin_queue, build up the fragment list of free memory, unmark
3226                  * pinned objects as we go, memzero() the empty fragments so they are ready for the
3227                  * next allocations.
3228                  */
3229                 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
3230                         degraded_mode = 1;
3231
3232                 /* prepare the pin queue for the next collection */
3233                 sgen_finish_pinning ();
3234
3235                 /* Clear TLABs for all threads */
3236                 sgen_clear_tlabs ();
3237
3238                 sgen_pin_stats_reset ();
3239         }
3240
3241         if (concurrent_collection_in_progress)
3242                 sgen_cement_concurrent_finish ();
3243         sgen_cement_clear_below_threshold ();
3244
3245         TV_GETTIME (atv);
3246         time_major_fragment_creation += TV_ELAPSED (btv, atv);
3247
3248         if (heap_dump_file)
3249                 dump_heap ("major", stat_major_gcs - 1, reason);
3250
3251         if (fin_ready_list || critical_fin_list) {
3252                 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
3253                 mono_gc_finalize_notify ();
3254         }
3255
3256         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3257
3258         sgen_memgov_major_collection_end ();
3259         current_collection_generation = -1;
3260
3261         major_collector.finish_major_collection ();
3262
3263         g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
3264
3265         if (concurrent_collection_in_progress)
3266                 concurrent_collection_in_progress = FALSE;
3267
3268         check_scan_starts ();
3269
3270         binary_protocol_flush_buffers (FALSE);
3271
3272         //consistency_check ();
3273
3274         MONO_GC_END (GENERATION_OLD);
3275         binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
3276 }
3277
3278 static gboolean
3279 major_do_collection (const char *reason)
3280 {
3281         TV_DECLARE (all_atv);
3282         TV_DECLARE (all_btv);
3283         int old_next_pin_slot;
3284
3285         if (disable_major_collections)
3286                 return FALSE;
3287
3288         if (major_collector.get_and_reset_num_major_objects_marked) {
3289                 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3290                 g_assert (!num_marked);
3291         }
3292
3293         /* world must be stopped already */
3294         TV_GETTIME (all_atv);
3295
3296         major_start_collection (FALSE, &old_next_pin_slot);
3297         major_finish_collection (reason, old_next_pin_slot, FALSE);
3298
3299         TV_GETTIME (all_btv);
3300         gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3301
3302         /* FIXME: also report this to the user, preferably in gc-end. */
3303         if (major_collector.get_and_reset_num_major_objects_marked)
3304                 major_collector.get_and_reset_num_major_objects_marked ();
3305
3306         return bytes_pinned_from_failed_allocation > 0;
3307 }
3308
3309 static void
3310 major_start_concurrent_collection (const char *reason)
3311 {
3312         long long num_objects_marked;
3313
3314         if (disable_major_collections)
3315                 return;
3316
3317         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3318         g_assert (num_objects_marked == 0);
3319
3320         MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3321
3322         // FIXME: store reason and pass it when finishing
3323         major_start_collection (TRUE, NULL);
3324
3325         gray_queue_redirect (&gray_queue);
3326         sgen_workers_wait_for_jobs ();
3327
3328         num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3329         MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3330
3331         current_collection_generation = -1;
3332 }
3333
3334 static gboolean
3335 major_update_or_finish_concurrent_collection (gboolean force_finish)
3336 {
3337         SgenGrayQueue unpin_queue;
3338         memset (&unpin_queue, 0, sizeof (unpin_queue));
3339
3340         MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3341
3342         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3343
3344         major_collector.update_cardtable_mod_union ();
3345         sgen_los_update_cardtable_mod_union ();
3346
3347         if (!force_finish && !sgen_workers_all_done ()) {
3348                 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3349                 return FALSE;
3350         }
3351
3352         if (mod_union_consistency_check)
3353                 sgen_check_mod_union_consistency ();
3354
3355         collect_nursery (&unpin_queue, TRUE);
3356
3357         current_collection_generation = GENERATION_OLD;
3358         major_finish_collection ("finishing", -1, TRUE);
3359
3360         if (whole_heap_check_before_collection)
3361                 sgen_check_whole_heap (FALSE);
3362
3363         unpin_objects_from_queue (&unpin_queue);
3364         sgen_gray_object_queue_deinit (&unpin_queue);
3365
3366         MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3367
3368         current_collection_generation = -1;
3369
3370         return TRUE;
3371 }
3372
3373 /*
3374  * Ensure an allocation request for @size will succeed by freeing enough memory.
3375  *
3376  * LOCKING: The GC lock MUST be held.
3377  */
3378 void
3379 sgen_ensure_free_space (size_t size)
3380 {
3381         int generation_to_collect = -1;
3382         const char *reason = NULL;
3383
3384
3385         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3386                 if (sgen_need_major_collection (size)) {
3387                         reason = "LOS overflow";
3388                         generation_to_collect = GENERATION_OLD;
3389                 }
3390         } else {
3391                 if (degraded_mode) {
3392                         if (sgen_need_major_collection (size)) {
3393                                 reason = "Degraded mode overflow";
3394                                 generation_to_collect = GENERATION_OLD;
3395                         }
3396                 } else if (sgen_need_major_collection (size)) {
3397                         reason = "Minor allowance";
3398                         generation_to_collect = GENERATION_OLD;
3399                 } else {
3400                         generation_to_collect = GENERATION_NURSERY;
3401                         reason = "Nursery full";
3402                 }
3403         }
3404
3405         if (generation_to_collect == -1) {
3406                 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3407                         generation_to_collect = GENERATION_OLD;
3408                         reason = "Finish concurrent collection";
3409                 }
3410         }
3411
3412         if (generation_to_collect == -1)
3413                 return;
3414         sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3415 }
3416
3417 /*
3418  * LOCKING: Assumes the GC lock is held.
3419  */
3420 void
3421 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3422 {
3423         TV_DECLARE (gc_end);
3424         GGTimingInfo infos [2];
3425         int overflow_generation_to_collect = -1;
3426         int oldest_generation_collected = generation_to_collect;
3427         const char *overflow_reason = NULL;
3428
3429         MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3430         if (wait_to_finish)
3431                 binary_protocol_collection_force (generation_to_collect);
3432
3433         g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3434
3435         memset (infos, 0, sizeof (infos));
3436         mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3437
3438         infos [0].generation = generation_to_collect;
3439         infos [0].reason = reason;
3440         infos [0].is_overflow = FALSE;
3441         TV_GETTIME (infos [0].total_time);
3442         infos [1].generation = -1;
3443
3444         sgen_stop_world (generation_to_collect);
3445
3446         if (concurrent_collection_in_progress) {
3447                 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3448                         oldest_generation_collected = GENERATION_OLD;
3449                         goto done;
3450                 }
3451                 if (generation_to_collect == GENERATION_OLD)
3452                         goto done;
3453         } else {
3454                 if (generation_to_collect == GENERATION_OLD &&
3455                                 allow_synchronous_major &&
3456                                 major_collector.want_synchronous_collection &&
3457                                 *major_collector.want_synchronous_collection) {
3458                         wait_to_finish = TRUE;
3459                 }
3460         }
3461
3462         //FIXME extract overflow reason
3463         if (generation_to_collect == GENERATION_NURSERY) {
3464                 if (collect_nursery (NULL, FALSE)) {
3465                         overflow_generation_to_collect = GENERATION_OLD;
3466                         overflow_reason = "Minor overflow";
3467                 }
3468         } else {
3469                 if (major_collector.is_concurrent) {
3470                         g_assert (!concurrent_collection_in_progress);
3471                         if (!wait_to_finish)
3472                                 collect_nursery (NULL, FALSE);
3473                 }
3474
3475                 if (major_collector.is_concurrent && !wait_to_finish) {
3476                         major_start_concurrent_collection (reason);
3477                         // FIXME: set infos[0] properly
3478                         goto done;
3479                 } else {
3480                         if (major_do_collection (reason)) {
3481                                 overflow_generation_to_collect = GENERATION_NURSERY;
3482                                 overflow_reason = "Excessive pinning";
3483                         }
3484                 }
3485         }
3486
3487         TV_GETTIME (gc_end);
3488         infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3489
3490
3491         if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3492                 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3493                 infos [1].generation = overflow_generation_to_collect;
3494                 infos [1].reason = overflow_reason;
3495                 infos [1].is_overflow = TRUE;
3496                 infos [1].total_time = gc_end;
3497
3498                 if (overflow_generation_to_collect == GENERATION_NURSERY)
3499                         collect_nursery (NULL, FALSE);
3500                 else
3501                         major_do_collection (overflow_reason);
3502
3503                 TV_GETTIME (gc_end);
3504                 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3505
3506                 /* keep events symmetric */
3507                 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3508
3509                 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3510         }
3511
3512         SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3513
3514         /* this also sets the proper pointers for the next allocation */
3515         if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3516                 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3517                 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3518                 sgen_dump_pin_queue ();
3519                 degraded_mode = 1;
3520         }
3521
3522  done:
3523         g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3524
3525         sgen_restart_world (oldest_generation_collected, infos);
3526
3527         mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3528 }
3529
3530 /*
3531  * ######################################################################
3532  * ########  Memory allocation from the OS
3533  * ######################################################################
3534  * This section of code deals with getting memory from the OS and
3535  * allocating memory for GC-internal data structures.
3536  * Internal memory can be handled with a freelist for small objects.
3537  */
3538
3539 /*
3540  * Debug reporting.
3541  */
3542 G_GNUC_UNUSED static void
3543 report_internal_mem_usage (void)
3544 {
3545         printf ("Internal memory usage:\n");
3546         sgen_report_internal_mem_usage ();
3547         printf ("Pinned memory usage:\n");
3548         major_collector.report_pinned_memory_usage ();
3549 }
3550
3551 /*
3552  * ######################################################################
3553  * ########  Finalization support
3554  * ######################################################################
3555  */
3556
3557 static inline gboolean
3558 sgen_major_is_object_alive (void *object)
3559 {
3560         mword objsize;
3561
3562         /* Oldgen objects can be pinned and forwarded too */
3563         if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3564                 return TRUE;
3565
3566         /*
3567          * FIXME: major_collector.is_object_live() also calculates the
3568          * size.  Avoid the double calculation.
3569          */
3570         objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3571         if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3572                 return sgen_los_object_is_pinned (object);
3573
3574         return major_collector.is_object_live (object);
3575 }
3576
3577 /*
3578  * If the object has been forwarded it means it's still referenced from a root.
3579  * If it is pinned it's still alive as well.
3580  * A LOS object is only alive if we have pinned it.
3581  * Return TRUE if @obj is ready to be finalized.
3582  */
3583 static inline gboolean
3584 sgen_is_object_alive (void *object)
3585 {
3586         if (ptr_in_nursery (object))
3587                 return sgen_nursery_is_object_alive (object);
3588
3589         return sgen_major_is_object_alive (object);
3590 }
3591
3592 /*
3593  * This function returns true if @object is either alive or it belongs to the old gen
3594  * and we're currently doing a minor collection.
3595  */
3596 static inline int
3597 sgen_is_object_alive_for_current_gen (char *object)
3598 {
3599         if (ptr_in_nursery (object))
3600                 return sgen_nursery_is_object_alive (object);
3601
3602         if (current_collection_generation == GENERATION_NURSERY)
3603                 return TRUE;
3604
3605         return sgen_major_is_object_alive (object);
3606 }
3607
3608 /*
3609  * This function returns true if @object is either alive and belongs to the
3610  * current collection - major collections are full heap, so old gen objects
3611  * are never alive during a minor collection.
3612  */
3613 static inline int
3614 sgen_is_object_alive_and_on_current_collection (char *object)
3615 {
3616         if (ptr_in_nursery (object))
3617                 return sgen_nursery_is_object_alive (object);
3618
3619         if (current_collection_generation == GENERATION_NURSERY)
3620                 return FALSE;
3621
3622         return sgen_major_is_object_alive (object);
3623 }
3624
3625
3626 gboolean
3627 sgen_gc_is_object_ready_for_finalization (void *object)
3628 {
3629         return !sgen_is_object_alive (object);
3630 }
3631
3632 static gboolean
3633 has_critical_finalizer (MonoObject *obj)
3634 {
3635         MonoClass *class;
3636
3637         if (!mono_defaults.critical_finalizer_object)
3638                 return FALSE;
3639
3640         class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3641
3642         return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3643 }
3644
3645 void
3646 sgen_queue_finalization_entry (MonoObject *obj)
3647 {
3648         FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3649         gboolean critical = has_critical_finalizer (obj);
3650         entry->object = obj;
3651         if (critical) {
3652                 entry->next = critical_fin_list;
3653                 critical_fin_list = entry;
3654         } else {
3655                 entry->next = fin_ready_list;
3656                 fin_ready_list = entry;
3657         }
3658
3659 #ifdef ENABLE_DTRACE
3660         if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3661                 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3662                 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3663                 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3664                                 vt->klass->name_space, vt->klass->name, gen, critical);
3665         }
3666 #endif
3667 }
3668
3669 gboolean
3670 sgen_object_is_live (void *obj)
3671 {
3672         return sgen_is_object_alive_and_on_current_collection (obj);
3673 }
3674
3675 /* LOCKING: requires that the GC lock is held */
3676 static void
3677 null_ephemerons_for_domain (MonoDomain *domain)
3678 {
3679         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3680
3681         while (current) {
3682                 MonoObject *object = (MonoObject*)current->array;
3683
3684                 if (object && !object->vtable) {
3685                         EphemeronLinkNode *tmp = current;
3686
3687                         if (prev)
3688                                 prev->next = current->next;
3689                         else
3690                                 ephemeron_list = current->next;
3691
3692                         current = current->next;
3693                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3694                 } else {
3695                         prev = current;
3696                         current = current->next;
3697                 }
3698         }
3699 }
3700
3701 /* LOCKING: requires that the GC lock is held */
3702 static void
3703 clear_unreachable_ephemerons (ScanCopyContext ctx)
3704 {
3705         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3706         GrayQueue *queue = ctx.queue;
3707         EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3708         MonoArray *array;
3709         Ephemeron *cur, *array_end;
3710         char *tombstone;
3711
3712         while (current) {
3713                 char *object = current->array;
3714
3715                 if (!sgen_is_object_alive_for_current_gen (object)) {
3716                         EphemeronLinkNode *tmp = current;
3717
3718                         SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3719
3720                         if (prev)
3721                                 prev->next = current->next;
3722                         else
3723                                 ephemeron_list = current->next;
3724
3725                         current = current->next;
3726                         sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3727
3728                         continue;
3729                 }
3730
3731                 copy_func ((void**)&object, queue);
3732                 current->array = object;
3733
3734                 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3735
3736                 array = (MonoArray*)object;
3737                 cur = mono_array_addr (array, Ephemeron, 0);
3738                 array_end = cur + mono_array_length_fast (array);
3739                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3740
3741                 for (; cur < array_end; ++cur) {
3742                         char *key = (char*)cur->key;
3743
3744                         if (!key || key == tombstone)
3745                                 continue;
3746
3747                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3748                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3749                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3750
3751                         if (!sgen_is_object_alive_for_current_gen (key)) {
3752                                 cur->key = tombstone;
3753                                 cur->value = NULL;
3754                                 continue;
3755                         }
3756                 }
3757                 prev = current;
3758                 current = current->next;
3759         }
3760 }
3761
3762 /*
3763 LOCKING: requires that the GC lock is held
3764
3765 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3766 */
3767 static int
3768 mark_ephemerons_in_range (ScanCopyContext ctx)
3769 {
3770         CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3771         GrayQueue *queue = ctx.queue;
3772         int nothing_marked = 1;
3773         EphemeronLinkNode *current = ephemeron_list;
3774         MonoArray *array;
3775         Ephemeron *cur, *array_end;
3776         char *tombstone;
3777
3778         for (current = ephemeron_list; current; current = current->next) {
3779                 char *object = current->array;
3780                 SGEN_LOG (5, "Ephemeron array at %p", object);
3781
3782                 /*It has to be alive*/
3783                 if (!sgen_is_object_alive_for_current_gen (object)) {
3784                         SGEN_LOG (5, "\tnot reachable");
3785                         continue;
3786                 }
3787
3788                 copy_func ((void**)&object, queue);
3789
3790                 array = (MonoArray*)object;
3791                 cur = mono_array_addr (array, Ephemeron, 0);
3792                 array_end = cur + mono_array_length_fast (array);
3793                 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3794
3795                 for (; cur < array_end; ++cur) {
3796                         char *key = cur->key;
3797
3798                         if (!key || key == tombstone)
3799                                 continue;
3800
3801                         SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3802                                 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3803                                 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3804
3805                         if (sgen_is_object_alive_for_current_gen (key)) {
3806                                 char *value = cur->value;
3807
3808                                 copy_func ((void**)&cur->key, queue);
3809                                 if (value) {
3810                                         if (!sgen_is_object_alive_for_current_gen (value))
3811                                                 nothing_marked = 0;
3812                                         copy_func ((void**)&cur->value, queue);
3813                                 }
3814                         }
3815                 }
3816         }
3817
3818         SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3819         return nothing_marked;
3820 }
3821
3822 int
3823 mono_gc_invoke_finalizers (void)
3824 {
3825         FinalizeReadyEntry *entry = NULL;
3826         gboolean entry_is_critical = FALSE;
3827         int count = 0;
3828         void *obj;
3829         /* FIXME: batch to reduce lock contention */
3830         while (fin_ready_list || critical_fin_list) {
3831                 LOCK_GC;
3832
3833                 if (entry) {
3834                         FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3835
3836                         /* We have finalized entry in the last
3837                            interation, now we need to remove it from
3838                            the list. */
3839                         if (*list == entry)
3840                                 *list = entry->next;
3841                         else {
3842                                 FinalizeReadyEntry *e = *list;
3843                                 while (e->next != entry)
3844                                         e = e->next;
3845                                 e->next = entry->next;
3846                         }
3847                         sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3848                         entry = NULL;
3849                 }
3850
3851                 /* Now look for the first non-null entry. */
3852                 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3853                         ;
3854                 if (entry) {
3855                         entry_is_critical = FALSE;
3856                 } else {
3857                         entry_is_critical = TRUE;
3858                         for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3859                                 ;
3860                 }
3861
3862                 if (entry) {
3863                         g_assert (entry->object);
3864                         num_ready_finalizers--;
3865                         obj = entry->object;
3866                         entry->object = NULL;
3867                         SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3868                 }
3869
3870                 UNLOCK_GC;
3871
3872                 if (!entry)
3873                         break;
3874
3875                 g_assert (entry->object == NULL);
3876                 count++;
3877                 /* the object is on the stack so it is pinned */
3878                 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3879                 mono_gc_run_finalize (obj, NULL);
3880         }
3881         g_assert (!entry);
3882         return count;
3883 }
3884
3885 gboolean
3886 mono_gc_pending_finalizers (void)
3887 {
3888         return fin_ready_list || critical_fin_list;
3889 }
3890
3891 /*
3892  * ######################################################################
3893  * ########  registered roots support
3894  * ######################################################################
3895  */
3896
3897 /*
3898  * We do not coalesce roots.
3899  */
3900 static int
3901 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3902 {
3903         RootRecord new_root;
3904         int i;
3905         LOCK_GC;
3906         for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3907                 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3908                 /* we allow changing the size and the descriptor (for thread statics etc) */
3909                 if (root) {
3910                         size_t old_size = root->end_root - start;
3911                         root->end_root = start + size;
3912                         g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3913                                           ((root->root_desc == 0) && (descr == NULL)));
3914                         root->root_desc = (mword)descr;
3915                         roots_size += size;
3916                         roots_size -= old_size;
3917                         UNLOCK_GC;
3918                         return TRUE;
3919                 }
3920         }
3921
3922         new_root.end_root = start + size;
3923         new_root.root_desc = (mword)descr;
3924
3925         sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3926         roots_size += size;
3927
3928         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);
3929
3930         UNLOCK_GC;
3931         return TRUE;
3932 }
3933
3934 int
3935 mono_gc_register_root (char *start, size_t size, void *descr)
3936 {
3937         return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3938 }
3939
3940 int
3941 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3942 {
3943         return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3944 }
3945
3946 void
3947 mono_gc_deregister_root (char* addr)
3948 {
3949         int root_type;
3950         RootRecord root;
3951
3952         LOCK_GC;
3953         for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3954                 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3955                         roots_size -= (root.end_root - addr);
3956         }
3957         UNLOCK_GC;
3958 }
3959
3960 /*
3961  * ######################################################################
3962  * ########  Thread handling (stop/start code)
3963  * ######################################################################
3964  */
3965
3966 unsigned int sgen_global_stop_count = 0;
3967
3968 int
3969 sgen_get_current_collection_generation (void)
3970 {
3971         return current_collection_generation;
3972 }
3973
3974 void
3975 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3976 {
3977         gc_callbacks = *callbacks;
3978 }
3979
3980 MonoGCCallbacks *
3981 mono_gc_get_gc_callbacks ()
3982 {
3983         return &gc_callbacks;
3984 }
3985
3986 /* Variables holding start/end nursery so it won't have to be passed at every call */
3987 static void *scan_area_arg_start, *scan_area_arg_end;
3988
3989 void
3990 mono_gc_conservatively_scan_area (void *start, void *end)
3991 {
3992         conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3993 }
3994
3995 void*
3996 mono_gc_scan_object (void *obj)
3997 {
3998         UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3999         current_object_ops.copy_or_mark_object (&obj, data->queue);
4000         return obj;
4001 }
4002
4003 /*
4004  * Mark from thread stacks and registers.
4005  */
4006 static void
4007 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
4008 {
4009         SgenThreadInfo *info;
4010
4011         scan_area_arg_start = start_nursery;
4012         scan_area_arg_end = end_nursery;
4013
4014         FOREACH_THREAD (info) {
4015                 if (info->skip) {
4016                         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);
4017                         continue;
4018                 }
4019                 if (info->gc_disabled) {
4020                         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);
4021                         continue;
4022                 }
4023                 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
4024                         SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %d)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, mono_thread_info_run_state (info));
4025                         continue;
4026                 }
4027                 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 ());
4028                 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
4029                         UserCopyOrMarkData data = { NULL, queue };
4030                         set_user_copy_or_mark_data (&data);
4031                         gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
4032                         set_user_copy_or_mark_data (NULL);
4033                 } else if (!precise) {
4034                         if (!conservative_stack_mark) {
4035                                 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
4036                                 conservative_stack_mark = TRUE;
4037                         }
4038                         conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
4039                 }
4040
4041                 if (!precise) {
4042 #ifdef USE_MONO_CTX
4043                         conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
4044                                 start_nursery, end_nursery, PIN_TYPE_STACK);
4045 #else
4046                         conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
4047                                         start_nursery, end_nursery, PIN_TYPE_STACK);
4048 #endif
4049                 }
4050         } END_FOREACH_THREAD
4051 }
4052
4053 static gboolean
4054 ptr_on_stack (void *ptr)
4055 {
4056         gpointer stack_start = &stack_start;
4057         SgenThreadInfo *info = mono_thread_info_current ();
4058
4059         if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
4060                 return TRUE;
4061         return FALSE;
4062 }
4063
4064 static void*
4065 sgen_thread_register (SgenThreadInfo* info, void *addr)
4066 {
4067 #ifndef HAVE_KW_THREAD
4068         info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
4069
4070         g_assert (!mono_native_tls_get_value (thread_info_key));
4071         mono_native_tls_set_value (thread_info_key, info);
4072 #else
4073         sgen_thread_info = info;
4074 #endif
4075
4076 #ifdef SGEN_POSIX_STW
4077         info->stop_count = -1;
4078         info->signal = 0;
4079 #endif
4080         info->skip = 0;
4081         info->stack_start = NULL;
4082         info->stopped_ip = NULL;
4083         info->stopped_domain = NULL;
4084 #ifdef USE_MONO_CTX
4085         memset (&info->ctx, 0, sizeof (MonoContext));
4086 #else
4087         memset (&info->regs, 0, sizeof (info->regs));
4088 #endif
4089
4090         sgen_init_tlab_info (info);
4091
4092         binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4093
4094         // FIXME: Unift with mono_thread_get_stack_bounds ()
4095         /* try to get it with attributes first */
4096 #if (defined(HAVE_PTHREAD_GETATTR_NP) || defined(HAVE_PTHREAD_ATTR_GET_NP)) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4097   {
4098      size_t size;
4099      void *sstart;
4100      pthread_attr_t attr;
4101
4102 #if defined(HAVE_PTHREAD_GETATTR_NP)
4103     /* Linux */
4104     pthread_getattr_np (pthread_self (), &attr);
4105 #elif defined(HAVE_PTHREAD_ATTR_GET_NP)
4106     /* BSD */
4107     pthread_attr_init (&attr);
4108     pthread_attr_get_np (pthread_self (), &attr);
4109 #else
4110 #error Cannot determine which API is needed to retrieve pthread attributes.
4111 #endif
4112
4113      pthread_attr_getstack (&attr, &sstart, &size);
4114      info->stack_start_limit = sstart;
4115      info->stack_end = (char*)sstart + size;
4116      pthread_attr_destroy (&attr);
4117   }
4118 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4119         {
4120                 size_t stsize = 0;
4121                 guint8 *staddr = NULL;
4122
4123                 mono_thread_get_stack_bounds (&staddr, &stsize);
4124                 info->stack_start_limit = staddr;
4125                 info->stack_end = staddr + stsize;
4126         }
4127 #else
4128         {
4129                 /* FIXME: we assume the stack grows down */
4130                 gsize stack_bottom = (gsize)addr;
4131                 stack_bottom += 4095;
4132                 stack_bottom &= ~4095;
4133                 info->stack_end = (char*)stack_bottom;
4134         }
4135 #endif
4136
4137 #ifdef HAVE_KW_THREAD
4138         stack_end = info->stack_end;
4139 #endif
4140
4141         SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
4142
4143         if (gc_callbacks.thread_attach_func)
4144                 info->runtime_data = gc_callbacks.thread_attach_func ();
4145         return info;
4146 }
4147
4148 static void
4149 sgen_thread_detach (SgenThreadInfo *p)
4150 {
4151         /* If a delegate is passed to native code and invoked on a thread we dont
4152          * know about, the jit will register it with mono_jit_thread_attach, but
4153          * we have no way of knowing when that thread goes away.  SGen has a TSD
4154          * so we assume that if the domain is still registered, we can detach
4155          * the thread
4156          */
4157         if (mono_domain_get ())
4158                 mono_thread_detach (mono_thread_current ());
4159 }
4160
4161 static void
4162 sgen_thread_unregister (SgenThreadInfo *p)
4163 {
4164         binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4165         SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)mono_thread_info_get_tid (p));
4166
4167         if (gc_callbacks.thread_detach_func) {
4168                 gc_callbacks.thread_detach_func (p->runtime_data);
4169                 p->runtime_data = NULL;
4170         }
4171 }
4172
4173
4174 static void
4175 sgen_thread_attach (SgenThreadInfo *info)
4176 {
4177         LOCK_GC;
4178         /*this is odd, can we get attached before the gc is inited?*/
4179         init_stats ();
4180         UNLOCK_GC;
4181
4182         if (gc_callbacks.thread_attach_func && !info->runtime_data)
4183                 info->runtime_data = gc_callbacks.thread_attach_func ();
4184 }
4185 gboolean
4186 mono_gc_register_thread (void *baseptr)
4187 {
4188         return mono_thread_info_attach (baseptr) != NULL;
4189 }
4190
4191 /*
4192  * mono_gc_set_stack_end:
4193  *
4194  *   Set the end of the current threads stack to STACK_END. The stack space between
4195  * STACK_END and the real end of the threads stack will not be scanned during collections.
4196  */
4197 void
4198 mono_gc_set_stack_end (void *stack_end)
4199 {
4200         SgenThreadInfo *info;
4201
4202         LOCK_GC;
4203         info = mono_thread_info_current ();
4204         if (info) {
4205                 g_assert (stack_end < info->stack_end);
4206                 info->stack_end = stack_end;
4207         }
4208         UNLOCK_GC;
4209 }
4210
4211 #if USE_PTHREAD_INTERCEPT
4212
4213
4214 int
4215 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4216 {
4217         return pthread_create (new_thread, attr, start_routine, arg);
4218 }
4219
4220 int
4221 mono_gc_pthread_join (pthread_t thread, void **retval)
4222 {
4223         return pthread_join (thread, retval);
4224 }
4225
4226 int
4227 mono_gc_pthread_detach (pthread_t thread)
4228 {
4229         return pthread_detach (thread);
4230 }
4231
4232 void
4233 mono_gc_pthread_exit (void *retval)
4234 {
4235         mono_thread_info_dettach ();
4236         pthread_exit (retval);
4237 }
4238
4239 #endif /* USE_PTHREAD_INTERCEPT */
4240
4241 /*
4242  * ######################################################################
4243  * ########  Write barriers
4244  * ######################################################################
4245  */
4246
4247 /*
4248  * Note: the write barriers first do the needed GC work and then do the actual store:
4249  * this way the value is visible to the conservative GC scan after the write barrier
4250  * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4251  * the conservative scan, otherwise by the remembered set scan.
4252  */
4253 void
4254 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4255 {
4256         HEAVY_STAT (++stat_wbarrier_set_field);
4257         if (ptr_in_nursery (field_ptr)) {
4258                 *(void**)field_ptr = value;
4259                 return;
4260         }
4261         SGEN_LOG (8, "Adding remset at %p", field_ptr);
4262         if (value)
4263                 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4264
4265         remset.wbarrier_set_field (obj, field_ptr, value);
4266 }
4267
4268 void
4269 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4270 {
4271         HEAVY_STAT (++stat_wbarrier_set_arrayref);
4272         if (ptr_in_nursery (slot_ptr)) {
4273                 *(void**)slot_ptr = value;
4274                 return;
4275         }
4276         SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4277         if (value)
4278                 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4279
4280         remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4281 }
4282
4283 void
4284 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4285 {
4286         HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4287         /*This check can be done without taking a lock since dest_ptr array is pinned*/
4288         if (ptr_in_nursery (dest_ptr) || count <= 0) {
4289                 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4290                 return;
4291         }
4292
4293 #ifdef SGEN_BINARY_PROTOCOL
4294         {
4295                 int i;
4296                 for (i = 0; i < count; ++i) {
4297                         gpointer dest = (gpointer*)dest_ptr + i;
4298                         gpointer obj = *((gpointer*)src_ptr + i);
4299                         if (obj)
4300                                 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4301                 }
4302         }
4303 #endif
4304
4305         remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4306 }
4307
4308 static char *found_obj;
4309
4310 static void
4311 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4312 {
4313         char *ptr = user_data;
4314
4315         if (ptr >= obj && ptr < obj + size) {
4316                 g_assert (!found_obj);
4317                 found_obj = obj;
4318         }
4319 }
4320
4321 /* for use in the debugger */
4322 char* find_object_for_ptr (char *ptr);
4323 char*
4324 find_object_for_ptr (char *ptr)
4325 {
4326         if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4327                 found_obj = NULL;
4328                 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4329                                 find_object_for_ptr_callback, ptr, TRUE);
4330                 if (found_obj)
4331                         return found_obj;
4332         }
4333
4334         found_obj = NULL;
4335         sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4336         if (found_obj)
4337                 return found_obj;
4338
4339         /*
4340          * Very inefficient, but this is debugging code, supposed to
4341          * be called from gdb, so we don't care.
4342          */
4343         found_obj = NULL;
4344         major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4345         return found_obj;
4346 }
4347
4348 void
4349 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4350 {
4351         gpointer obj;
4352
4353         HEAVY_STAT (++stat_wbarrier_generic_store);
4354
4355 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4356         /* FIXME: ptr_in_heap must be called with the GC lock held */
4357         if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4358                 char *start = find_object_for_ptr (ptr);
4359                 MonoObject *value = *(MonoObject**)ptr;
4360                 LOCK_GC;
4361                 g_assert (start);
4362                 if (start) {
4363                         MonoObject *obj = (MonoObject*)start;
4364                         if (obj->vtable->domain != value->vtable->domain)
4365                                 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4366                 }
4367                 UNLOCK_GC;
4368         }
4369 #endif
4370
4371         obj = *(gpointer*)ptr;
4372         if (obj)
4373                 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4374
4375         if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4376                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4377                 return;
4378         }
4379
4380         /*
4381          * We need to record old->old pointer locations for the
4382          * concurrent collector.
4383          */
4384         if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4385                 SGEN_LOG (8, "Skipping remset at %p", ptr);
4386                 return;
4387         }
4388
4389         SGEN_LOG (8, "Adding remset at %p", ptr);
4390
4391         remset.wbarrier_generic_nostore (ptr);
4392 }
4393
4394 void
4395 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4396 {
4397         SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4398         *(void**)ptr = value;
4399         if (ptr_in_nursery (value))
4400                 mono_gc_wbarrier_generic_nostore (ptr);
4401         sgen_dummy_use (value);
4402 }
4403
4404 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4405  * as an atomic operation with release semantics.
4406  */
4407 void
4408 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4409 {
4410         HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4411
4412         SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4413
4414         InterlockedWritePointer (ptr, value);
4415
4416         if (ptr_in_nursery (value))
4417                 mono_gc_wbarrier_generic_nostore (ptr);
4418
4419         sgen_dummy_use (value);
4420 }
4421
4422 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4423 {
4424         mword *dest = _dest;
4425         mword *src = _src;
4426
4427         while (size) {
4428                 if (bitmap & 0x1)
4429                         mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4430                 else
4431                         *dest = *src;
4432                 ++src;
4433                 ++dest;
4434                 size -= SIZEOF_VOID_P;
4435                 bitmap >>= 1;
4436         }
4437 }
4438
4439 #ifdef SGEN_BINARY_PROTOCOL
4440 #undef HANDLE_PTR
4441 #define HANDLE_PTR(ptr,obj) do {                                        \
4442                 gpointer o = *(gpointer*)(ptr);                         \
4443                 if ((o)) {                                              \
4444                         gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4445                         binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4446                 }                                                       \
4447         } while (0)
4448
4449 static void
4450 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4451 {
4452 #define SCAN_OBJECT_NOVTABLE
4453 #include "sgen-scan-object.h"
4454 }
4455 #endif
4456
4457 void
4458 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4459 {
4460         HEAVY_STAT (++stat_wbarrier_value_copy);
4461         g_assert (klass->valuetype);
4462
4463         SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4464
4465         if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4466                 size_t element_size = mono_class_value_size (klass, NULL);
4467                 size_t size = count * element_size;
4468                 mono_gc_memmove (dest, src, size);
4469                 return;
4470         }
4471
4472 #ifdef SGEN_BINARY_PROTOCOL
4473         {
4474                 size_t element_size = mono_class_value_size (klass, NULL);
4475                 int i;
4476                 for (i = 0; i < count; ++i) {
4477                         scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4478                                         (char*)src + i * element_size - sizeof (MonoObject),
4479                                         (mword) klass->gc_descr);
4480                 }
4481         }
4482 #endif
4483
4484         remset.wbarrier_value_copy (dest, src, count, klass);
4485 }
4486
4487 /**
4488  * mono_gc_wbarrier_object_copy:
4489  *
4490  * Write barrier to call when obj is the result of a clone or copy of an object.
4491  */
4492 void
4493 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4494 {
4495         int size;
4496
4497         HEAVY_STAT (++stat_wbarrier_object_copy);
4498
4499         if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4500                 size = mono_object_class (obj)->instance_size;
4501                 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4502                                 size - sizeof (MonoObject));
4503                 return;
4504         }
4505
4506 #ifdef SGEN_BINARY_PROTOCOL
4507         scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4508 #endif
4509
4510         remset.wbarrier_object_copy (obj, src);
4511 }
4512
4513
4514 /*
4515  * ######################################################################
4516  * ########  Other mono public interface functions.
4517  * ######################################################################
4518  */
4519
4520 #define REFS_SIZE 128
4521 typedef struct {
4522         void *data;
4523         MonoGCReferences callback;
4524         int flags;
4525         int count;
4526         int called;
4527         MonoObject *refs [REFS_SIZE];
4528         uintptr_t offsets [REFS_SIZE];
4529 } HeapWalkInfo;
4530
4531 #undef HANDLE_PTR
4532 #define HANDLE_PTR(ptr,obj)     do {    \
4533                 if (*(ptr)) {   \
4534                         if (hwi->count == REFS_SIZE) {  \
4535                                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);    \
4536                                 hwi->count = 0; \
4537                                 hwi->called = 1;        \
4538                         }       \
4539                         hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start;  \
4540                         hwi->refs [hwi->count++] = *(ptr);      \
4541                 }       \
4542         } while (0)
4543
4544 static void
4545 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4546 {
4547 #include "sgen-scan-object.h"
4548 }
4549
4550 static void
4551 walk_references (char *start, size_t size, void *data)
4552 {
4553         HeapWalkInfo *hwi = data;
4554         hwi->called = 0;
4555         hwi->count = 0;
4556         collect_references (hwi, start, size);
4557         if (hwi->count || !hwi->called)
4558                 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4559 }
4560
4561 /**
4562  * mono_gc_walk_heap:
4563  * @flags: flags for future use
4564  * @callback: a function pointer called for each object in the heap
4565  * @data: a user data pointer that is passed to callback
4566  *
4567  * This function can be used to iterate over all the live objects in the heap:
4568  * for each object, @callback is invoked, providing info about the object's
4569  * location in memory, its class, its size and the objects it references.
4570  * For each referenced object it's offset from the object address is
4571  * reported in the offsets array.
4572  * The object references may be buffered, so the callback may be invoked
4573  * multiple times for the same object: in all but the first call, the size
4574  * argument will be zero.
4575  * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4576  * profiler event handler.
4577  *
4578  * Returns: a non-zero value if the GC doesn't support heap walking
4579  */
4580 int
4581 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4582 {
4583         HeapWalkInfo hwi;
4584
4585         hwi.flags = flags;
4586         hwi.callback = callback;
4587         hwi.data = data;
4588
4589         sgen_clear_nursery_fragments ();
4590         sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4591
4592         major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4593         sgen_los_iterate_objects (walk_references, &hwi);
4594
4595         return 0;
4596 }
4597
4598 void
4599 mono_gc_collect (int generation)
4600 {
4601         LOCK_GC;
4602         if (generation > 1)
4603                 generation = 1;
4604         sgen_perform_collection (0, generation, "user request", TRUE);
4605         UNLOCK_GC;
4606 }
4607
4608 int
4609 mono_gc_max_generation (void)
4610 {
4611         return 1;
4612 }
4613
4614 int
4615 mono_gc_collection_count (int generation)
4616 {
4617         if (generation == 0)
4618                 return stat_minor_gcs;
4619         return stat_major_gcs;
4620 }
4621
4622 int64_t
4623 mono_gc_get_used_size (void)
4624 {
4625         gint64 tot = 0;
4626         LOCK_GC;
4627         tot = los_memory_usage;
4628         tot += nursery_section->next_data - nursery_section->data;
4629         tot += major_collector.get_used_size ();
4630         /* FIXME: account for pinned objects */
4631         UNLOCK_GC;
4632         return tot;
4633 }
4634
4635 int
4636 mono_gc_get_los_limit (void)
4637 {
4638         return MAX_SMALL_OBJ_SIZE;
4639 }
4640
4641 gboolean
4642 mono_gc_user_markers_supported (void)
4643 {
4644         return TRUE;
4645 }
4646
4647 gboolean
4648 mono_object_is_alive (MonoObject* o)
4649 {
4650         return TRUE;
4651 }
4652
4653 int
4654 mono_gc_get_generation (MonoObject *obj)
4655 {
4656         if (ptr_in_nursery (obj))
4657                 return 0;
4658         return 1;
4659 }
4660
4661 void
4662 mono_gc_enable_events (void)
4663 {
4664 }
4665
4666 void
4667 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4668 {
4669         sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4670 }
4671
4672 void
4673 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4674 {
4675         sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4676 }
4677
4678 MonoObject*
4679 mono_gc_weak_link_get (void **link_addr)
4680 {
4681         void * volatile *link_addr_volatile;
4682         void *ptr;
4683         MonoObject *obj;
4684  retry:
4685         link_addr_volatile = link_addr;
4686         ptr = (void*)*link_addr_volatile;
4687         /*
4688          * At this point we have a hidden pointer.  If the GC runs
4689          * here, it will not recognize the hidden pointer as a
4690          * reference, and if the object behind it is not referenced
4691          * elsewhere, it will be freed.  Once the world is restarted
4692          * we reveal the pointer, giving us a pointer to a freed
4693          * object.  To make sure we don't return it, we load the
4694          * hidden pointer again.  If it's still the same, we can be
4695          * sure the object reference is valid.
4696          */
4697         if (ptr)
4698                 obj = (MonoObject*) REVEAL_POINTER (ptr);
4699         else
4700                 return NULL;
4701
4702         mono_memory_barrier ();
4703
4704         /*
4705          * During the second bridge processing step the world is
4706          * running again.  That step processes all weak links once
4707          * more to null those that refer to dead objects.  Before that
4708          * is completed, those links must not be followed, so we
4709          * conservatively wait for bridge processing when any weak
4710          * link is dereferenced.
4711          */
4712         if (G_UNLIKELY (bridge_processing_in_progress))
4713                 mono_gc_wait_for_bridge_processing ();
4714
4715         if ((void*)*link_addr_volatile != ptr)
4716                 goto retry;
4717
4718         return obj;
4719 }
4720
4721 gboolean
4722 mono_gc_ephemeron_array_add (MonoObject *obj)
4723 {
4724         EphemeronLinkNode *node;
4725
4726         LOCK_GC;
4727
4728         node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4729         if (!node) {
4730                 UNLOCK_GC;
4731                 return FALSE;
4732         }
4733         node->array = (char*)obj;
4734         node->next = ephemeron_list;
4735         ephemeron_list = node;
4736
4737         SGEN_LOG (5, "Registered ephemeron array %p", obj);
4738
4739         UNLOCK_GC;
4740         return TRUE;
4741 }
4742
4743 gboolean
4744 mono_gc_set_allow_synchronous_major (gboolean flag)
4745 {
4746         if (!major_collector.is_concurrent)
4747                 return flag;
4748
4749         allow_synchronous_major = flag;
4750         return TRUE;
4751 }
4752
4753 void*
4754 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4755 {
4756         void *result;
4757         LOCK_INTERRUPTION;
4758         result = func (data);
4759         UNLOCK_INTERRUPTION;
4760         return result;
4761 }
4762
4763 gboolean
4764 mono_gc_is_gc_thread (void)
4765 {
4766         gboolean result;
4767         LOCK_GC;
4768         result = mono_thread_info_current () != NULL;
4769         UNLOCK_GC;
4770         return result;
4771 }
4772
4773 static gboolean
4774 is_critical_method (MonoMethod *method)
4775 {
4776         return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4777 }
4778
4779 void
4780 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4781 {
4782         va_list ap;
4783
4784         va_start (ap, description_format);
4785
4786         fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4787         vfprintf (stderr, description_format, ap);
4788         if (fallback)
4789                 fprintf (stderr, " - %s", fallback);
4790         fprintf (stderr, "\n");
4791
4792         va_end (ap);
4793 }
4794
4795 static gboolean
4796 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4797 {
4798         char *endptr;
4799         double val = strtod (opt, &endptr);
4800         if (endptr == opt) {
4801                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4802                 return FALSE;
4803         }
4804         else if (val < min || val > max) {
4805                 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4806                 return FALSE;
4807         }
4808         *result = val;
4809         return TRUE;
4810 }
4811
4812 void
4813 mono_gc_base_init (void)
4814 {
4815         MonoThreadInfoCallbacks cb;
4816         const char *env;
4817         char **opts, **ptr;
4818         char *major_collector_opt = NULL;
4819         char *minor_collector_opt = NULL;
4820         glong max_heap = 0;
4821         glong soft_limit = 0;
4822         int num_workers;
4823         int result;
4824         int dummy;
4825         gboolean debug_print_allowance = FALSE;
4826         double allowance_ratio = 0, save_target = 0;
4827         gboolean have_split_nursery = FALSE;
4828         gboolean cement_enabled = TRUE;
4829
4830         do {
4831                 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4832                 switch (result) {
4833                 case 1:
4834                         /* already inited */
4835                         return;
4836                 case -1:
4837                         /* being inited by another thread */
4838                         g_usleep (1000);
4839                         break;
4840                 case 0:
4841                         /* we will init it */
4842                         break;
4843                 default:
4844                         g_assert_not_reached ();
4845                 }
4846         } while (result != 0);
4847
4848         LOCK_INIT (gc_mutex);
4849
4850         pagesize = mono_pagesize ();
4851         gc_debug_file = stderr;
4852
4853         cb.thread_register = sgen_thread_register;
4854         cb.thread_detach = sgen_thread_detach;
4855         cb.thread_unregister = sgen_thread_unregister;
4856         cb.thread_attach = sgen_thread_attach;
4857         cb.mono_method_is_critical = (gpointer)is_critical_method;
4858 #ifndef HOST_WIN32
4859         cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4860 #endif
4861
4862         mono_threads_init (&cb, sizeof (SgenThreadInfo));
4863
4864         LOCK_INIT (sgen_interruption_mutex);
4865         LOCK_INIT (pin_queue_mutex);
4866
4867         init_user_copy_or_mark_key ();
4868
4869         if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4870                 opts = g_strsplit (env, ",", -1);
4871                 for (ptr = opts; *ptr; ++ptr) {
4872                         char *opt = *ptr;
4873                         if (g_str_has_prefix (opt, "major=")) {
4874                                 opt = strchr (opt, '=') + 1;
4875                                 major_collector_opt = g_strdup (opt);
4876                         } else if (g_str_has_prefix (opt, "minor=")) {
4877                                 opt = strchr (opt, '=') + 1;
4878                                 minor_collector_opt = g_strdup (opt);
4879                         }
4880                 }
4881         } else {
4882                 opts = NULL;
4883         }
4884
4885         init_stats ();
4886         sgen_init_internal_allocator ();
4887         sgen_init_nursery_allocator ();
4888         sgen_init_fin_weak_hash ();
4889
4890         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4891         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4892         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4893         sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4894
4895 #ifndef HAVE_KW_THREAD
4896         mono_native_tls_alloc (&thread_info_key, NULL);
4897 #if defined(__APPLE__) || defined (HOST_WIN32)
4898         /*
4899          * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4900          * where the two are the same.
4901          */
4902         mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4903 #endif
4904 #else
4905         {
4906                 int tls_offset = -1;
4907                 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4908                 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4909         }
4910 #endif
4911
4912         /*
4913          * This needs to happen before any internal allocations because
4914          * it inits the small id which is required for hazard pointer
4915          * operations.
4916          */
4917         sgen_os_init ();
4918
4919         mono_thread_info_attach (&dummy);
4920
4921         if (!minor_collector_opt) {
4922                 sgen_simple_nursery_init (&sgen_minor_collector);
4923         } else {
4924                 if (!strcmp (minor_collector_opt, "simple")) {
4925                 use_simple_nursery:
4926                         sgen_simple_nursery_init (&sgen_minor_collector);
4927                 } else if (!strcmp (minor_collector_opt, "split")) {
4928                         sgen_split_nursery_init (&sgen_minor_collector);
4929                         have_split_nursery = TRUE;
4930                 } else {
4931                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4932                         goto use_simple_nursery;
4933                 }
4934         }
4935
4936         if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4937         use_marksweep_major:
4938                 sgen_marksweep_init (&major_collector);
4939         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4940                 sgen_marksweep_fixed_init (&major_collector);
4941         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4942                 sgen_marksweep_par_init (&major_collector);
4943         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4944                 sgen_marksweep_fixed_par_init (&major_collector);
4945         } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4946                 sgen_marksweep_conc_init (&major_collector);
4947         } else {
4948                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4949                 goto use_marksweep_major;
4950         }
4951
4952         if (have_split_nursery && major_collector.is_parallel) {
4953                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4954                 have_split_nursery = FALSE;
4955         }
4956
4957         num_workers = mono_cpu_count ();
4958         g_assert (num_workers > 0);
4959         if (num_workers > 16)
4960                 num_workers = 16;
4961
4962         ///* Keep this the default for now */
4963         /* Precise marking is broken on all supported targets. Disable until fixed. */
4964         conservative_stack_mark = TRUE;
4965
4966         sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4967
4968         if (opts) {
4969                 gboolean usage_printed = FALSE;
4970
4971                 for (ptr = opts; *ptr; ++ptr) {
4972                         char *opt = *ptr;
4973                         if (!strcmp (opt, ""))
4974                                 continue;
4975                         if (g_str_has_prefix (opt, "major="))
4976                                 continue;
4977                         if (g_str_has_prefix (opt, "minor="))
4978                                 continue;
4979                         if (g_str_has_prefix (opt, "max-heap-size=")) {
4980                                 glong max_heap_candidate = 0;
4981                                 opt = strchr (opt, '=') + 1;
4982                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4983                                         max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(glong)(mono_pagesize () - 1);
4984                                         if (max_heap != max_heap_candidate)
4985                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4986                                 } else {
4987                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4988                                 }
4989                                 continue;
4990                         }
4991                         if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4992                                 opt = strchr (opt, '=') + 1;
4993                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4994                                         if (soft_limit <= 0) {
4995                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4996                                                 soft_limit = 0;
4997                                         }
4998                                 } else {
4999                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
5000                                 }
5001                                 continue;
5002                         }
5003                         if (g_str_has_prefix (opt, "workers=")) {
5004                                 long val;
5005                                 char *endptr;
5006                                 if (!major_collector.is_parallel) {
5007                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
5008                                         continue;
5009                                 }
5010                                 opt = strchr (opt, '=') + 1;
5011                                 val = strtol (opt, &endptr, 10);
5012                                 if (!*opt || *endptr) {
5013                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
5014                                         continue;
5015                                 }
5016                                 if (val <= 0 || val > 16) {
5017                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
5018                                         continue;
5019                                 }
5020                                 num_workers = (int)val;
5021                                 continue;
5022                         }
5023                         if (g_str_has_prefix (opt, "stack-mark=")) {
5024                                 opt = strchr (opt, '=') + 1;
5025                                 if (!strcmp (opt, "precise")) {
5026                                         conservative_stack_mark = FALSE;
5027                                 } else if (!strcmp (opt, "conservative")) {
5028                                         conservative_stack_mark = TRUE;
5029                                 } else {
5030                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
5031                                                         "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
5032                                 }
5033                                 continue;
5034                         }
5035                         if (g_str_has_prefix (opt, "bridge=")) {
5036                                 opt = strchr (opt, '=') + 1;
5037                                 sgen_register_test_bridge_callbacks (g_strdup (opt));
5038                                 continue;
5039                         }
5040 #ifdef USER_CONFIG
5041                         if (g_str_has_prefix (opt, "nursery-size=")) {
5042                                 long val;
5043                                 opt = strchr (opt, '=') + 1;
5044                                 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
5045 #ifdef SGEN_ALIGN_NURSERY
5046                                         if ((val & (val - 1))) {
5047                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
5048                                                 continue;
5049                                         }
5050
5051                                         if (val < SGEN_MAX_NURSERY_WASTE) {
5052                                                 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
5053                                                                 "`nursery-size` must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
5054                                                 continue;
5055                                         }
5056
5057                                         sgen_nursery_size = val;
5058                                         sgen_nursery_bits = 0;
5059                                         while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
5060                                                 ;
5061 #else
5062                                         sgen_nursery_size = val;
5063 #endif
5064                                 } else {
5065                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
5066                                         continue;
5067                                 }
5068                                 continue;
5069                         }
5070 #endif
5071                         if (g_str_has_prefix (opt, "save-target-ratio=")) {
5072                                 double val;
5073                                 opt = strchr (opt, '=') + 1;
5074                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
5075                                                 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
5076                                         save_target = val;
5077                                 }
5078                                 continue;
5079                         }
5080                         if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
5081                                 double val;
5082                                 opt = strchr (opt, '=') + 1;
5083                                 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
5084                                                 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
5085                                         allowance_ratio = val;
5086                                 }
5087                                 continue;
5088                         }
5089                         if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
5090                                 if (!major_collector.is_concurrent) {
5091                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
5092                                         continue;
5093                                 }
5094
5095                                 opt = strchr (opt, '=') + 1;
5096
5097                                 if (!strcmp (opt, "yes")) {
5098                                         allow_synchronous_major = TRUE;
5099                                 } else if (!strcmp (opt, "no")) {
5100                                         allow_synchronous_major = FALSE;
5101                                 } else {
5102                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
5103                                         continue;
5104                                 }
5105                         }
5106
5107                         if (!strcmp (opt, "cementing")) {
5108                                 if (major_collector.is_parallel) {
5109                                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported for the parallel major collector.");
5110                                         continue;
5111                                 }
5112                                 cement_enabled = TRUE;
5113                                 continue;
5114                         }
5115                         if (!strcmp (opt, "no-cementing")) {
5116                                 cement_enabled = FALSE;
5117                                 continue;
5118                         }
5119
5120                         if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
5121                                 continue;
5122
5123                         if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
5124                                 continue;
5125
5126                         sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5127
5128                         if (usage_printed)
5129                                 continue;
5130
5131                         fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
5132                         fprintf (stderr, "  max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5133                         fprintf (stderr, "  soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
5134                         fprintf (stderr, "  nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
5135                         fprintf (stderr, "  major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
5136                         fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
5137                         fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
5138                         fprintf (stderr, "  stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
5139                         fprintf (stderr, "  [no-]cementing\n");
5140                         if (major_collector.is_concurrent)
5141                                 fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
5142                         if (major_collector.print_gc_param_usage)
5143                                 major_collector.print_gc_param_usage ();
5144                         if (sgen_minor_collector.print_gc_param_usage)
5145                                 sgen_minor_collector.print_gc_param_usage ();
5146                         fprintf (stderr, " Experimental options:\n");
5147                         fprintf (stderr, "  save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
5148                         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);
5149                         fprintf (stderr, "\n");
5150
5151                         usage_printed = TRUE;
5152                 }
5153                 g_strfreev (opts);
5154         }
5155
5156         if (major_collector.is_parallel) {
5157                 cement_enabled = FALSE;
5158                 sgen_workers_init (num_workers);
5159         } else if (major_collector.is_concurrent) {
5160                 sgen_workers_init (1);
5161         }
5162
5163         if (major_collector_opt)
5164                 g_free (major_collector_opt);
5165
5166         if (minor_collector_opt)
5167                 g_free (minor_collector_opt);
5168
5169         alloc_nursery ();
5170
5171         sgen_cement_init (cement_enabled);
5172
5173         if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
5174                 gboolean usage_printed = FALSE;
5175
5176                 opts = g_strsplit (env, ",", -1);
5177                 for (ptr = opts; ptr && *ptr; ptr ++) {
5178                         char *opt = *ptr;
5179                         if (!strcmp (opt, ""))
5180                                 continue;
5181                         if (opt [0] >= '0' && opt [0] <= '9') {
5182                                 gc_debug_level = atoi (opt);
5183                                 opt++;
5184                                 if (opt [0] == ':')
5185                                         opt++;
5186                                 if (opt [0]) {
5187 #ifdef HOST_WIN32
5188                                         char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
5189 #else
5190                                         char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
5191 #endif
5192                                         gc_debug_file = fopen (rf, "wb");
5193                                         if (!gc_debug_file)
5194                                                 gc_debug_file = stderr;
5195                                         g_free (rf);
5196                                 }
5197                         } else if (!strcmp (opt, "print-allowance")) {
5198                                 debug_print_allowance = TRUE;
5199                         } else if (!strcmp (opt, "print-pinning")) {
5200                                 do_pin_stats = TRUE;
5201                         } else if (!strcmp (opt, "verify-before-allocs")) {
5202                                 verify_before_allocs = 1;
5203                                 has_per_allocation_action = TRUE;
5204                         } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5205                                 char *arg = strchr (opt, '=') + 1;
5206                                 verify_before_allocs = atoi (arg);
5207                                 has_per_allocation_action = TRUE;
5208                         } else if (!strcmp (opt, "collect-before-allocs")) {
5209                                 collect_before_allocs = 1;
5210                                 has_per_allocation_action = TRUE;
5211                         } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5212                                 char *arg = strchr (opt, '=') + 1;
5213                                 has_per_allocation_action = TRUE;
5214                                 collect_before_allocs = atoi (arg);
5215                         } else if (!strcmp (opt, "verify-before-collections")) {
5216                                 whole_heap_check_before_collection = TRUE;
5217                         } else if (!strcmp (opt, "check-at-minor-collections")) {
5218                                 consistency_check_at_minor_collection = TRUE;
5219                                 nursery_clear_policy = CLEAR_AT_GC;
5220                         } else if (!strcmp (opt, "mod-union-consistency-check")) {
5221                                 if (!major_collector.is_concurrent) {
5222                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
5223                                         continue;
5224                                 }
5225                                 mod_union_consistency_check = TRUE;
5226                         } else if (!strcmp (opt, "check-mark-bits")) {
5227                                 check_mark_bits_after_major_collection = TRUE;
5228                         } else if (!strcmp (opt, "check-nursery-pinned")) {
5229                                 check_nursery_objects_pinned = TRUE;
5230                         } else if (!strcmp (opt, "xdomain-checks")) {
5231                                 xdomain_checks = TRUE;
5232                         } else if (!strcmp (opt, "clear-at-gc")) {
5233                                 nursery_clear_policy = CLEAR_AT_GC;
5234                         } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5235                                 nursery_clear_policy = CLEAR_AT_GC;
5236                         } else if (!strcmp (opt, "check-scan-starts")) {
5237                                 do_scan_starts_check = TRUE;
5238                         } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5239                                 do_verify_nursery = TRUE;
5240                         } else if (!strcmp (opt, "check-concurrent")) {
5241                                 if (!major_collector.is_concurrent) {
5242                                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5243                                         continue;
5244                                 }
5245                                 do_concurrent_checks = TRUE;
5246                         } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5247                                 do_dump_nursery_content = TRUE;
5248                         } else if (!strcmp (opt, "no-managed-allocator")) {
5249                                 sgen_set_use_managed_allocator (FALSE);
5250                         } else if (!strcmp (opt, "disable-minor")) {
5251                                 disable_minor_collections = TRUE;
5252                         } else if (!strcmp (opt, "disable-major")) {
5253                                 disable_major_collections = TRUE;
5254                         } else if (g_str_has_prefix (opt, "heap-dump=")) {
5255                                 char *filename = strchr (opt, '=') + 1;
5256                                 nursery_clear_policy = CLEAR_AT_GC;
5257                                 heap_dump_file = fopen (filename, "w");
5258                                 if (heap_dump_file) {
5259                                         fprintf (heap_dump_file, "<sgen-dump>\n");
5260                                         do_pin_stats = TRUE;
5261                                 }
5262 #ifdef SGEN_BINARY_PROTOCOL
5263                         } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5264                                 char *filename = strchr (opt, '=') + 1;
5265                                 binary_protocol_init (filename);
5266 #endif
5267                         } else {
5268                                 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5269
5270                                 if (usage_printed)
5271                                         continue;
5272
5273                                 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);
5274                                 fprintf (stderr, "Valid <option>s are:\n");
5275                                 fprintf (stderr, "  collect-before-allocs[=<n>]\n");
5276                                 fprintf (stderr, "  verify-before-allocs[=<n>]\n");
5277                                 fprintf (stderr, "  check-at-minor-collections\n");
5278                                 fprintf (stderr, "  check-mark-bits\n");
5279                                 fprintf (stderr, "  check-nursery-pinned\n");
5280                                 fprintf (stderr, "  verify-before-collections\n");
5281                                 fprintf (stderr, "  verify-nursery-at-minor-gc\n");
5282                                 fprintf (stderr, "  dump-nursery-at-minor-gc\n");
5283                                 fprintf (stderr, "  disable-minor\n");
5284                                 fprintf (stderr, "  disable-major\n");
5285                                 fprintf (stderr, "  xdomain-checks\n");
5286                                 fprintf (stderr, "  check-concurrent\n");
5287                                 fprintf (stderr, "  clear-at-gc\n");
5288                                 fprintf (stderr, "  clear-nursery-at-gc\n");
5289                                 fprintf (stderr, "  check-scan-starts\n");
5290                                 fprintf (stderr, "  no-managed-allocator\n");
5291                                 fprintf (stderr, "  print-allowance\n");
5292                                 fprintf (stderr, "  print-pinning\n");
5293                                 fprintf (stderr, "  heap-dump=<filename>\n");
5294 #ifdef SGEN_BINARY_PROTOCOL
5295                                 fprintf (stderr, "  binary-protocol=<filename>\n");
5296 #endif
5297                                 fprintf (stderr, "\n");
5298
5299                                 usage_printed = TRUE;
5300                         }
5301                 }
5302                 g_strfreev (opts);
5303         }
5304
5305         if (major_collector.is_parallel) {
5306                 if (heap_dump_file) {
5307                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5308                         fclose (heap_dump_file);
5309                         heap_dump_file = NULL;
5310                 }
5311                 if (do_pin_stats) {
5312                         sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5313                         do_pin_stats = FALSE;
5314                 }
5315         }
5316
5317         if (major_collector.post_param_init)
5318                 major_collector.post_param_init (&major_collector);
5319
5320         sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5321
5322         memset (&remset, 0, sizeof (remset));
5323
5324         sgen_card_table_init (&remset);
5325
5326         gc_initialized = 1;
5327 }
5328
5329 const char *
5330 mono_gc_get_gc_name (void)
5331 {
5332         return "sgen";
5333 }
5334
5335 static MonoMethod *write_barrier_method;
5336
5337 gboolean
5338 sgen_is_critical_method (MonoMethod *method)
5339 {
5340         return (method == write_barrier_method || sgen_is_managed_allocator (method));
5341 }
5342
5343 gboolean
5344 sgen_has_critical_method (void)
5345 {
5346         return write_barrier_method || sgen_has_managed_allocator ();
5347 }
5348
5349 #ifndef DISABLE_JIT
5350
5351 static void
5352 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5353 {
5354         memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5355 #ifdef SGEN_ALIGN_NURSERY
5356         // if (ptr_in_nursery (ptr)) return;
5357         /*
5358          * Masking out the bits might be faster, but we would have to use 64 bit
5359          * immediates, which might be slower.
5360          */
5361         mono_mb_emit_ldarg (mb, 0);
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 [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5366
5367         if (!major_collector.is_concurrent) {
5368                 // if (!ptr_in_nursery (*ptr)) return;
5369                 mono_mb_emit_ldarg (mb, 0);
5370                 mono_mb_emit_byte (mb, CEE_LDIND_I);
5371                 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5372                 mono_mb_emit_byte (mb, CEE_SHR_UN);
5373                 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5374                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5375         }
5376 #else
5377         int label_continue1, label_continue2;
5378         int dereferenced_var;
5379
5380         // if (ptr < (sgen_get_nursery_start ())) goto continue;
5381         mono_mb_emit_ldarg (mb, 0);
5382         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5383         label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5384
5385         // if (ptr >= sgen_get_nursery_end ())) goto continue;
5386         mono_mb_emit_ldarg (mb, 0);
5387         mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5388         label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5389
5390         // Otherwise return
5391         nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5392
5393         // continue:
5394         mono_mb_patch_branch (mb, label_continue_1);
5395         mono_mb_patch_branch (mb, label_continue_2);
5396
5397         // Dereference and store in local var
5398         dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5399         mono_mb_emit_ldarg (mb, 0);
5400         mono_mb_emit_byte (mb, CEE_LDIND_I);
5401         mono_mb_emit_stloc (mb, dereferenced_var);
5402
5403         if (!major_collector.is_concurrent) {
5404                 // if (*ptr < sgen_get_nursery_start ()) return;
5405                 mono_mb_emit_ldloc (mb, dereferenced_var);
5406                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5407                 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5408
5409                 // if (*ptr >= sgen_get_nursery_end ()) return;
5410                 mono_mb_emit_ldloc (mb, dereferenced_var);
5411                 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5412                 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5413         }
5414 #endif
5415 }
5416 #endif
5417
5418 MonoMethod*
5419 mono_gc_get_write_barrier (void)
5420 {
5421         MonoMethod *res;
5422         MonoMethodBuilder *mb;
5423         MonoMethodSignature *sig;
5424 #ifdef MANAGED_WBARRIER
5425         int i, nursery_check_labels [3];
5426
5427 #ifdef HAVE_KW_THREAD
5428         int stack_end_offset = -1;
5429
5430         MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5431         g_assert (stack_end_offset != -1);
5432 #endif
5433 #endif
5434
5435         // FIXME: Maybe create a separate version for ctors (the branch would be
5436         // correctly predicted more times)
5437         if (write_barrier_method)
5438                 return write_barrier_method;
5439
5440         /* Create the IL version of mono_gc_barrier_generic_store () */
5441         sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5442         sig->ret = &mono_defaults.void_class->byval_arg;
5443         sig->params [0] = &mono_defaults.int_class->byval_arg;
5444
5445         mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5446
5447 #ifndef DISABLE_JIT
5448 #ifdef MANAGED_WBARRIER
5449         emit_nursery_check (mb, nursery_check_labels);
5450         /*
5451         addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5452         *addr = 1;
5453
5454         sgen_cardtable:
5455                 LDC_PTR sgen_cardtable
5456
5457         address >> CARD_BITS
5458                 LDARG_0
5459                 LDC_I4 CARD_BITS
5460                 SHR_UN
5461         if (SGEN_HAVE_OVERLAPPING_CARDS) {
5462                 LDC_PTR card_table_mask
5463                 AND
5464         }
5465         AND
5466         ldc_i4_1
5467         stind_i1
5468         */
5469         mono_mb_emit_ptr (mb, sgen_cardtable);
5470         mono_mb_emit_ldarg (mb, 0);
5471         mono_mb_emit_icon (mb, CARD_BITS);
5472         mono_mb_emit_byte (mb, CEE_SHR_UN);
5473 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5474         mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5475         mono_mb_emit_byte (mb, CEE_AND);
5476 #endif
5477         mono_mb_emit_byte (mb, CEE_ADD);
5478         mono_mb_emit_icon (mb, 1);
5479         mono_mb_emit_byte (mb, CEE_STIND_I1);
5480
5481         // return;
5482         for (i = 0; i < 3; ++i) {
5483                 if (nursery_check_labels [i])
5484                         mono_mb_patch_branch (mb, nursery_check_labels [i]);
5485         }
5486         mono_mb_emit_byte (mb, CEE_RET);
5487 #else
5488         mono_mb_emit_ldarg (mb, 0);
5489         mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5490         mono_mb_emit_byte (mb, CEE_RET);
5491 #endif
5492 #endif
5493         res = mono_mb_create_method (mb, sig, 16);
5494         mono_mb_free (mb);
5495
5496         mono_loader_lock ();
5497         if (write_barrier_method) {
5498                 /* Already created */
5499                 mono_free_method (res);
5500         } else {
5501                 /* double-checked locking */
5502                 mono_memory_barrier ();
5503                 write_barrier_method = res;
5504         }
5505         mono_loader_unlock ();
5506
5507         return write_barrier_method;
5508 }
5509
5510 char*
5511 mono_gc_get_description (void)
5512 {
5513         return g_strdup ("sgen");
5514 }
5515
5516 void
5517 mono_gc_set_desktop_mode (void)
5518 {
5519 }
5520
5521 gboolean
5522 mono_gc_is_moving (void)
5523 {
5524         return TRUE;
5525 }
5526
5527 gboolean
5528 mono_gc_is_disabled (void)
5529 {
5530         return FALSE;
5531 }
5532
5533 #ifdef HOST_WIN32
5534 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5535 {
5536         return TRUE;
5537 }
5538 #endif
5539
5540 NurseryClearPolicy
5541 sgen_get_nursery_clear_policy (void)
5542 {
5543         return nursery_clear_policy;
5544 }
5545
5546 MonoVTable*
5547 sgen_get_array_fill_vtable (void)
5548 {
5549         if (!array_fill_vtable) {
5550                 static MonoClass klass;
5551                 static MonoVTable vtable;
5552                 gsize bmap;
5553
5554                 MonoDomain *domain = mono_get_root_domain ();
5555                 g_assert (domain);
5556
5557                 klass.element_class = mono_defaults.byte_class;
5558                 klass.rank = 1;
5559                 klass.instance_size = sizeof (MonoArray);
5560                 klass.sizes.element_size = 1;
5561                 klass.name = "array_filler_type";
5562
5563                 vtable.klass = &klass;
5564                 bmap = 0;
5565                 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5566                 vtable.rank = 1;
5567
5568                 array_fill_vtable = &vtable;
5569         }
5570         return array_fill_vtable;
5571 }
5572
5573 void
5574 sgen_gc_lock (void)
5575 {
5576         LOCK_GC;
5577 }
5578
5579 void
5580 sgen_gc_unlock (void)
5581 {
5582         UNLOCK_GC;
5583 }
5584
5585 void
5586 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5587 {
5588         major_collector.iterate_live_block_ranges (callback);
5589 }
5590
5591 void
5592 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5593 {
5594         major_collector.scan_card_table (FALSE, queue);
5595 }
5596
5597 SgenMajorCollector*
5598 sgen_get_major_collector (void)
5599 {
5600         return &major_collector;
5601 }
5602
5603 void mono_gc_set_skip_thread (gboolean skip)
5604 {
5605         SgenThreadInfo *info = mono_thread_info_current ();
5606
5607         LOCK_GC;
5608         info->gc_disabled = skip;
5609         UNLOCK_GC;
5610 }
5611
5612 SgenRemeberedSet*
5613 sgen_get_remset (void)
5614 {
5615         return &remset;
5616 }
5617
5618 guint
5619 mono_gc_get_vtable_bits (MonoClass *class)
5620 {
5621         if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5622                 return SGEN_GC_BIT_BRIDGE_OBJECT;
5623         return 0;
5624 }
5625
5626 void
5627 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5628 {
5629         // FIXME:
5630 }
5631
5632
5633 void
5634 sgen_check_whole_heap_stw (void)
5635 {
5636         sgen_stop_world (0);
5637         sgen_clear_nursery_fragments ();
5638         sgen_check_whole_heap (FALSE);
5639         sgen_restart_world (0, NULL);
5640 }
5641
5642 void
5643 sgen_gc_event_moves (void)
5644 {
5645         if (moved_objects_idx) {
5646                 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5647                 moved_objects_idx = 0;
5648         }
5649 }
5650
5651 #endif /* HAVE_SGEN_GC */