2 * mini-gc.c: GC interface for the mono JIT
5 * Zoltan Varga (vargaz@gmail.com)
7 * Copyright 2009 Novell, Inc (http://www.novell.com)
12 #include <mono/metadata/gc-internal.h>
17 #include <mono/metadata/gc-internal.h>
18 #include <mono/utils/mono-counters.h>
20 /* Contains state needed by the GC Map construction code */
23 * This contains information about stack slots initialized in the prolog, encoded using
24 * (slot_index << 16) | slot_type. The slot_index is relative to the CFA, i.e. 0
25 * means cfa+0, 1 means cfa-4/8, etc.
27 GSList *stack_slots_from_cfa;
28 /* Same for stack slots relative to the frame pointer */
29 GSList *stack_slots_from_fp;
31 /* Number of slots in the map */
33 /* The number of registers in the map */
35 /* Min and Max offsets of the stack frame relative to fp */
36 int min_offset, max_offset;
37 /* Same for the locals area */
38 int locals_min_offset, locals_max_offset;
40 /* The call sites where this frame can be stopped during GC */
41 GCCallSite **callsites;
42 /* The number of call sites */
46 * The width of the stack bitmaps in bytes. This is not equal to the bitmap width at
47 * runtime, since it includes columns which are 0.
49 int stack_bitmap_width;
51 * A bitmap whose width equals nslots, and whose height equals ncallsites.
52 * The bitmap contains a 1 if the corresponding stack slot has type SLOT_REF at the
55 guint8 *stack_ref_bitmap;
56 /* Same for SLOT_PIN */
57 guint8 *stack_pin_bitmap;
60 * Similar bitmaps for registers. These have width MONO_MAX_IREGS in bits.
63 guint8 *reg_ref_bitmap;
64 guint8 *reg_pin_bitmap;
67 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
70 #define DEBUG(s) do { s; } while (0)
71 #define DEBUG_ENABLED 1
77 #define DEBUG_GC_MAP(s) do { s; fflush (stdout); } while (0)
79 #define DEBUG_GC_MAP(s)
82 #define GC_BITS_PER_WORD (sizeof (gsize) * 8)
85 * Contains information collected during the conservative stack marking pass,
86 * used during the precise pass. This helps to avoid doing a stack walk twice, which
92 int frame_start_offset;
94 /* Relative to stack_start */
95 int reg_locations [MONO_MAX_IREGS];
99 int regs [MONO_MAX_IREGS];
103 /* Max number of frames stored in the TLS data */
104 #define MAX_FRAMES 50
107 * Per-thread data kept by this module. This is stored in the GC and passed to us as
108 * parameters, instead of being stored in a TLS variable, since during a collection,
109 * only the collection thread is active.
114 gboolean has_context;
115 MonoJitTlsData *jit_tls;
118 /* Number of frames collected during the !precise pass */
120 FrameInfo frames [MAX_FRAMES];
123 /* These are constant so don't store them in the GC Maps */
124 /* Number of registers stored in gc maps */
125 #define NREGS MONO_MAX_IREGS
129 * Contains information needed to mark a stack frame.
130 * This is a transient structure, created from a compressed representation on-demand.
134 * The offsets of the GC tracked area inside the stack frame relative to the frame pointer.
135 * This includes memory which is NOREF thus doesn't need GC maps.
140 * The offset relative to frame_offset where the the memory described by the GC maps
144 /* The number of stack slots in the map */
146 /* The frame pointer register */
148 /* The size of each callsite table entry */
149 guint8 callsite_entry_size;
150 guint has_pin_slots : 1;
151 guint has_ref_slots : 1;
152 guint has_ref_regs : 1;
153 guint has_pin_regs : 1;
155 /* The offsets below are into an external bitmaps array */
158 * A bitmap whose width is equal to bitmap_width, and whose height is equal to ncallsites.
159 * The bitmap contains a 1 if the corresponding stack slot has type SLOT_REF at the
162 guint32 stack_ref_bitmap_offset;
164 * Same for SLOT_PIN. It is possible that the same bit is set in both bitmaps at
165 * different callsites, if the slot starts out as PIN, and later changes to REF.
167 guint32 stack_pin_bitmap_offset;
170 * Corresponding bitmaps for registers
171 * These have width equal to the number of bits set in reg_ref_mask/reg_pin_mask.
172 * FIXME: Merge these with the normal bitmaps, i.e. reserve the first x slots for them ?
174 guint32 reg_pin_bitmap_offset;
175 guint32 reg_ref_bitmap_offset;
177 guint32 used_int_regs, reg_ref_mask, reg_pin_mask;
179 /* The number of bits set in the two masks above */
180 guint8 nref_regs, npin_regs;
183 * A bit array marking slots which contain refs.
184 * This is used only for debugging.
188 /* Callsite offsets */
189 /* These can take up a lot of space, so encode them compactly */
199 * A compressed version of GCMap. This is what gets stored in MonoJitInfo.
203 //guint8 encoded_size;
206 * The arrays below are embedded after the struct.
207 * Their address needs to be computed.
210 /* The fixed fields of the GCMap encoded using LEB128 */
211 guint8 encoded [MONO_ZERO_LEN_ARRAY];
213 /* An array of ncallsites entries, each entry is callsite_entry_size bytes long */
214 guint8 callsites [MONO_ZERO_LEN_ARRAY];
217 guint8 bitmaps [MONO_ZERO_LEN_ARRAY];
220 static int precise_frame_count [2], precise_frame_limit = -1;
221 static gboolean precise_frame_limit_inited;
227 int scanned_precisely;
228 int scanned_conservatively;
229 int scanned_registers;
239 int gc_callsites_size;
240 int gc_callsites8_size;
241 int gc_callsites16_size;
242 int gc_callsites32_size;
244 int gc_map_struct_size;
248 static JITGCStats stats;
250 // FIXME: Move these to a shared place
253 encode_uleb128 (guint32 value, guint8 *buf, guint8 **endbuf)
258 guint8 b = value & 0x7f;
260 if (value != 0) /* more bytes to come */
268 static G_GNUC_UNUSED void
269 encode_sleb128 (gint32 value, guint8 *buf, guint8 **endbuf)
272 gboolean negative = (value < 0);
280 /* the following is unnecessary if the
281 * implementation of >>= uses an arithmetic rather
282 * than logical shift for a signed left operand
286 value |= - (1 <<(size - 7));
287 /* sign bit of byte is second high order bit (0x40) */
288 if ((value == 0 && !(byte & 0x40)) ||
289 (value == -1 && (byte & 0x40)))
299 static inline guint32
300 decode_uleb128 (guint8 *buf, guint8 **endbuf)
310 res = res | (((int)(b & 0x7f)) << shift);
322 decode_sleb128 (guint8 *buf, guint8 **endbuf)
332 res = res | (((int)(b & 0x7f)) << shift);
335 if (shift < 32 && (b & 0x40))
336 res |= - (1 << shift);
347 encode_frame_reg (int frame_reg)
350 if (frame_reg == AMD64_RSP)
352 else if (frame_reg == AMD64_RBP)
357 g_assert_not_reached ();
362 decode_frame_reg (int encoded)
367 else if (encoded == 1)
372 g_assert_not_reached ();
378 static int callee_saved_regs [] = { AMD64_RBP, AMD64_RBX, AMD64_R12, AMD64_R13, AMD64_R14, AMD64_R15, AMD64_RDI, AMD64_RSI };
380 static int callee_saved_regs [] = { AMD64_RBP, AMD64_RBX, AMD64_R12, AMD64_R13, AMD64_R14, AMD64_R15 };
385 encode_regmask (guint32 regmask)
392 for (i = 0; i < sizeof (callee_saved_regs) / sizeof (int); ++i) {
393 if (regmask & (1 << callee_saved_regs [i])) {
395 regmask -= (1 << callee_saved_regs [i]);
398 g_assert (regmask == 0);
407 decode_regmask (guint32 regmask)
414 for (i = 0; i < sizeof (callee_saved_regs) / sizeof (int); ++i)
415 if (regmask & (1 << i))
416 res |= (1 << callee_saved_regs [i]);
427 * Encode the fixed fields of MAP into a buffer pointed to by BUF.
430 encode_gc_map (GCMap *map, guint8 *buf, guint8 **endbuf)
434 encode_sleb128 (map->start_offset / sizeof (mgreg_t), buf, &buf);
435 encode_sleb128 (map->end_offset / sizeof (mgreg_t), buf, &buf);
436 encode_sleb128 (map->map_offset / sizeof (mgreg_t), buf, &buf);
437 encode_uleb128 (map->nslots, buf, &buf);
438 g_assert (map->callsite_entry_size <= 4);
439 freg = encode_frame_reg (map->frame_reg);
441 flags = (map->has_ref_slots ? 1 : 0) | (map->has_pin_slots ? 2 : 0) | (map->has_ref_regs ? 4 : 0) | (map->has_pin_regs ? 8 : 0) | ((map->callsite_entry_size - 1) << 4) | (freg << 6);
442 encode_uleb128 (flags, buf, &buf);
443 encode_uleb128 (encode_regmask (map->used_int_regs), buf, &buf);
444 if (map->has_ref_regs)
445 encode_uleb128 (encode_regmask (map->reg_ref_mask), buf, &buf);
446 if (map->has_pin_regs)
447 encode_uleb128 (encode_regmask (map->reg_pin_mask), buf, &buf);
448 encode_uleb128 (map->ncallsites, buf, &buf);
456 * Decode the encoded GC map representation in BUF and store the result into MAP.
459 decode_gc_map (guint8 *buf, GCMap *map, guint8 **endbuf)
462 int stack_bitmap_size, reg_ref_bitmap_size, reg_pin_bitmap_size, offset, freg;
465 map->start_offset = decode_sleb128 (buf, &buf) * sizeof (mgreg_t);
466 map->end_offset = decode_sleb128 (buf, &buf) * sizeof (mgreg_t);
467 map->map_offset = decode_sleb128 (buf, &buf) * sizeof (mgreg_t);
468 map->nslots = decode_uleb128 (buf, &buf);
469 flags = decode_uleb128 (buf, &buf);
470 map->has_ref_slots = (flags & 1) ? 1 : 0;
471 map->has_pin_slots = (flags & 2) ? 1 : 0;
472 map->has_ref_regs = (flags & 4) ? 1 : 0;
473 map->has_pin_regs = (flags & 8) ? 1 : 0;
474 map->callsite_entry_size = ((flags >> 4) & 0x3) + 1;
476 map->frame_reg = decode_frame_reg (freg);
477 map->used_int_regs = decode_regmask (decode_uleb128 (buf, &buf));
478 if (map->has_ref_regs) {
479 map->reg_ref_mask = decode_regmask (decode_uleb128 (buf, &buf));
481 for (i = 0; i < NREGS; ++i)
482 if (map->reg_ref_mask & (1 << i))
486 if (map->has_pin_regs) {
487 map->reg_pin_mask = decode_regmask (decode_uleb128 (buf, &buf));
489 for (i = 0; i < NREGS; ++i)
490 if (map->reg_pin_mask & (1 << i))
494 map->ncallsites = decode_uleb128 (buf, &buf);
496 stack_bitmap_size = (ALIGN_TO (map->nslots, 8) / 8) * map->ncallsites;
497 reg_ref_bitmap_size = (ALIGN_TO (map->nref_regs, 8) / 8) * map->ncallsites;
498 reg_pin_bitmap_size = (ALIGN_TO (map->npin_regs, 8) / 8) * map->ncallsites;
500 map->stack_ref_bitmap_offset = offset;
501 if (map->has_ref_slots)
502 offset += stack_bitmap_size;
503 map->stack_pin_bitmap_offset = offset;
504 if (map->has_pin_slots)
505 offset += stack_bitmap_size;
506 map->reg_ref_bitmap_offset = offset;
507 if (map->has_ref_regs)
508 offset += reg_ref_bitmap_size;
509 map->reg_pin_bitmap_offset = offset;
510 if (map->has_pin_regs)
511 offset += reg_pin_bitmap_size;
517 thread_attach_func (void)
521 tls = g_new0 (TlsData, 1);
522 tls->tid = GetCurrentThreadId ();
523 stats.tlsdata_size += sizeof (TlsData);
529 thread_detach_func (gpointer user_data)
531 TlsData *tls = user_data;
537 thread_suspend_func (gpointer user_data, void *sigctx)
539 TlsData *tls = user_data;
542 /* Happens during startup */
545 tls->lmf = mono_get_lmf ();
547 mono_arch_sigctx_to_monoctx (sigctx, &tls->ctx);
548 tls->has_context = TRUE;
550 tls->has_context = FALSE;
552 tls->jit_tls = TlsGetValue (mono_jit_tls_id);
555 #define DEAD_REF ((gpointer)(gssize)0x2a2a2a2a2a2a2a2aULL)
558 set_bit (guint8 *bitmap, int width, int y, int x)
560 bitmap [(width * y) + (x / 8)] |= (1 << (x % 8));
564 clear_bit (guint8 *bitmap, int width, int y, int x)
566 bitmap [(width * y) + (x / 8)] &= ~(1 << (x % 8));
570 get_bit (guint8 *bitmap, int width, int y, int x)
572 return bitmap [(width * y) + (x / 8)] & (1 << (x % 8));
576 slot_type_to_string (GCSlotType type)
586 g_assert_not_reached ();
592 * conservatively_pass:
594 * Mark a thread stack conservatively and collect information needed by the precise pass.
597 conservative_pass (TlsData *tls, guint8 *stack_start, guint8 *stack_end)
600 MonoContext ctx, new_ctx;
603 gboolean last = TRUE;
607 guint8* fp, *p, *real_frame_start, *frame_start, *frame_end;
608 int i, pc_offset, cindex, bitmap_width;
609 int scanned = 0, scanned_precisely, scanned_conservatively, scanned_registers;
611 StackFrameInfo frame;
612 mgreg_t *reg_locations [MONO_MAX_IREGS];
613 mgreg_t *new_reg_locations [MONO_MAX_IREGS];
616 guint32 precise_regmask;
618 /* tls == NULL can happen during startup */
619 if (mono_thread_internal_current () == NULL || !tls) {
620 mono_gc_conservatively_scan_area (stack_start, stack_end);
621 stats.scanned_stacks += stack_end - stack_start;
628 /* Number of bytes scanned based on GC map data */
630 /* Number of bytes scanned precisely based on GC map data */
631 scanned_precisely = 0;
632 /* Number of bytes scanned conservatively based on GC map data */
633 scanned_conservatively = 0;
634 /* Number of bytes scanned conservatively in register save areas */
635 scanned_registers = 0;
637 /* This is one past the last address which we have scanned */
638 stack_limit = stack_start;
640 if (!tls->has_context)
641 memset (&new_ctx, 0, sizeof (ctx));
643 memcpy (&new_ctx, &tls->ctx, sizeof (MonoContext));
645 memset (reg_locations, 0, sizeof (reg_locations));
646 memset (new_reg_locations, 0, sizeof (new_reg_locations));
651 memcpy (&ctx, &new_ctx, sizeof (ctx));
653 for (i = 0; i < MONO_MAX_IREGS; ++i) {
654 if (new_reg_locations [i]) {
656 * If the current frame saves the register, it means it might modify its
657 * value, thus the old location might not contain the same value, so
658 * we have to mark it conservatively.
660 if (reg_locations [i]) {
661 DEBUG (printf ("\tscan saved reg %s location %p.\n", mono_arch_regname (i), reg_locations [i]));
662 mono_gc_conservatively_scan_area (reg_locations [i], reg_locations [i] + sizeof (mgreg_t));
663 scanned_registers += sizeof (mgreg_t);
666 reg_locations [i] = new_reg_locations [i];
668 DEBUG (printf ("\treg %s is at location %p.\n", mono_arch_regname (i), reg_locations [i]));
672 g_assert ((guint64)stack_limit % sizeof (mgreg_t) == 0);
674 #ifdef MONO_ARCH_HAVE_FIND_JIT_INFO_EXT
675 res = mono_find_jit_info_ext (frame.domain ? frame.domain : mono_domain_get (), tls->jit_tls, NULL, &ctx, &new_ctx, NULL, &lmf, new_reg_locations, &frame);
682 /* The last frame can be in any state so mark conservatively */
690 /* This happens with native-to-managed transitions */
691 if (!(MONO_CONTEXT_GET_IP (&ctx) >= ji->code_start && (guint8*)MONO_CONTEXT_GET_IP (&ctx) < (guint8*)ji->code_start + ji->code_size))
694 /* These frames are very problematic */
695 if (ji->method->wrapper_type == MONO_WRAPPER_MANAGED_TO_NATIVE) {
696 DEBUG (char *fname = mono_method_full_name (ji->method, TRUE); printf ("Mark(0): %s+0x%x (%p)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx)); g_free (fname));
697 DEBUG (printf ("\tSkip.\n"));
701 /* All the other frames are at a call site */
703 if (tls->nframes == MAX_FRAMES) {
705 * Can't save information since the array is full. So scan the rest of the
706 * stack conservatively.
708 DEBUG (printf ("Mark (0): Frame stack full.\n"));
712 /* Scan the frame of this method */
715 * A frame contains the following:
720 * - localloc-ed memory
722 pc_offset = (guint8*)MONO_CONTEXT_GET_IP (&ctx) - (guint8*)ji->code_start;
723 g_assert (pc_offset >= 0);
728 DEBUG (char *fname = mono_method_full_name (ji->method, TRUE); printf ("Mark(0): %s+0x%x (%p)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx)); g_free (fname));
729 DEBUG (printf ("\tNo GC Map.\n"));
734 * Debugging aid to control the number of frames scanned precisely
736 if (!precise_frame_limit_inited) {
737 if (getenv ("MONO_PRECISE_COUNT"))
738 precise_frame_limit = atoi (getenv ("MONO_PRECISE_COUNT"));
739 precise_frame_limit_inited = TRUE;
742 if (precise_frame_limit != -1) {
743 if (precise_frame_count [FALSE] == precise_frame_limit)
744 printf ("LAST PRECISE FRAME: %s\n", mono_method_full_name (ji->method, TRUE));
745 if (precise_frame_count [FALSE] > precise_frame_limit)
748 precise_frame_count [FALSE] ++;
750 /* Decode the encoded GC map */
752 memset (map, 0, sizeof (GCMap));
753 decode_gc_map (&emap->encoded [0], map, &p);
754 p = (guint8*)ALIGN_TO (p, map->callsite_entry_size);
755 map->callsites.offsets8 = p;
756 p += map->callsite_entry_size * map->ncallsites;
760 if (map->frame_reg == AMD64_RSP)
761 fp = (guint8*)ctx.rsp;
762 else if (map->frame_reg == AMD64_RBP)
763 fp = (guint8*)ctx.rbp;
765 g_assert_not_reached ();
768 g_assert_not_reached ();
771 real_frame_start = fp + map->start_offset;
772 frame_start = fp + map->start_offset + map->map_offset;
773 frame_end = fp + map->end_offset;
775 DEBUG (char *fname = mono_method_full_name (ji->method, TRUE); printf ("Mark(0): %s+0x%x (%p) limit=%p fp=%p frame=%p-%p (%d)\n", fname, pc_offset, (gpointer)MONO_CONTEXT_GET_IP (&ctx), stack_limit, fp, frame_start, frame_end, (int)(frame_end - frame_start)); g_free (fname));
777 /* Find the callsite index */
778 if (ji->code_size < 256) {
779 for (i = 0; i < map->ncallsites; ++i)
780 /* ip points inside the call instruction */
781 if (map->callsites.offsets8 [i] == pc_offset + 1)
783 } else if (ji->code_size < 65536) {
784 // FIXME: Use a binary search
785 for (i = 0; i < map->ncallsites; ++i)
786 /* ip points inside the call instruction */
787 if (map->callsites.offsets16 [i] == pc_offset + 1)
790 // FIXME: Use a binary search
791 for (i = 0; i < map->ncallsites; ++i)
792 /* ip points inside the call instruction */
793 if (map->callsites.offsets32 [i] == pc_offset + 1)
796 if (i == map->ncallsites) {
797 printf ("Unable to find ip offset 0x%x in callsite list of %s.\n", pc_offset + 1, mono_method_full_name (ji->method, TRUE));
798 g_assert_not_reached ();
802 g_assert (real_frame_start >= stack_limit);
804 if (real_frame_start > stack_limit) {
805 /* This scans the previously skipped frames as well */
806 DEBUG (printf ("\tscan area %p-%p (%d).\n", stack_limit, real_frame_start, (int)(real_frame_start - stack_limit)));
807 mono_gc_conservatively_scan_area (stack_limit, real_frame_start);
808 stats.scanned_other += real_frame_start - stack_limit;
811 /* Mark stack slots */
812 if (map->has_pin_slots) {
813 int bitmap_width = ALIGN_TO (map->nslots, 8) / 8;
814 guint8 *pin_bitmap = &bitmaps [map->stack_pin_bitmap_offset + (bitmap_width * cindex)];
819 for (i = 0; i < map->nslots; ++i) {
820 pinned = pin_bitmap [i / 8] & (1 << (i % 8));
822 DEBUG (printf ("\tscan slot %s0x%x(fp)=%p.\n", (guint8*)p > (guint8*)fp ? "" : "-", ABS ((int)((gssize)p - (gssize)fp)), p));
823 mono_gc_conservatively_scan_area (p, p + sizeof (mgreg_t));
824 scanned_conservatively += sizeof (mgreg_t);
826 scanned_precisely += sizeof (mgreg_t);
828 p += sizeof (mgreg_t);
831 scanned_precisely += (map->nslots * sizeof (mgreg_t));
834 /* The area outside of start-end is NOREF */
835 scanned_precisely += (map->end_offset - map->start_offset) - (map->nslots * sizeof (mgreg_t));
838 precise_regmask = map->used_int_regs | (1 << map->frame_reg);
839 if (map->has_pin_regs) {
840 int bitmap_width = ALIGN_TO (map->npin_regs, 8) / 8;
841 guint8 *pin_bitmap = &bitmaps [map->reg_pin_bitmap_offset + (bitmap_width * cindex)];
843 for (i = 0; i < NREGS; ++i) {
844 if (!(map->used_int_regs & (1 << i)))
847 if (!(map->reg_pin_mask & (1 << i)))
850 if (pin_bitmap [bindex / 8] & (1 << (bindex % 8))) {
851 DEBUG (printf ("\treg %s saved at 0x%p is pinning.\n", mono_arch_regname (i), reg_locations [i]));
852 precise_regmask &= ~(1 << i);
858 scanned += map->end_offset - map->start_offset;
860 g_assert (scanned == scanned_precisely + scanned_conservatively);
862 stack_limit = frame_end;
864 /* Save information for the precise pass */
865 fi = &tls->frames [tls->nframes];
866 fi->nslots = map->nslots;
867 bitmap_width = ALIGN_TO (map->nslots, 8) / 8;
868 if (map->has_ref_slots)
869 fi->bitmap = &bitmaps [map->stack_ref_bitmap_offset + (bitmap_width * cindex)];
872 fi->frame_start_offset = frame_start - stack_start;
873 fi->nreg_locations = 0;
877 if (map->has_ref_regs) {
878 int bitmap_width = ALIGN_TO (map->nref_regs, 8) / 8;
879 guint8 *ref_bitmap = &bitmaps [map->reg_ref_bitmap_offset + (bitmap_width * cindex)];
881 for (i = 0; i < NREGS; ++i) {
882 if (!(map->reg_ref_mask & (1 << i)))
885 if (reg_locations [i] && (ref_bitmap [bindex / 8] & (1 << (bindex % 8)))) {
886 DEBUG (fi->regs [fi->nreg_locations] = i);
887 DEBUG (printf ("\treg %s saved at 0x%p is ref.\n", mono_arch_regname (i), reg_locations [i]));
888 fi->reg_locations [fi->nreg_locations] = (guint8*)reg_locations [i] - stack_start;
889 fi->nreg_locations ++;
896 * Clear locations of precisely stacked registers.
898 if (precise_regmask) {
899 for (i = 0; i < NREGS; ++i) {
900 if (precise_regmask & (1 << i)) {
902 * The method uses this register, and we have precise info for it.
903 * This means the location will be scanned precisely.
904 * Tell the code at the beginning of the loop that this location is
907 if (reg_locations [i])
908 DEBUG (printf ("\treg %s at location %p is precise.\n", mono_arch_regname (i), reg_locations [i]));
909 reg_locations [i] = NULL;
917 /* Scan the remaining register save locations */
918 for (i = 0; i < MONO_MAX_IREGS; ++i) {
919 if (reg_locations [i]) {
920 DEBUG (printf ("\tscan saved reg location %p.\n", reg_locations [i]));
921 mono_gc_conservatively_scan_area (reg_locations [i], reg_locations [i] + sizeof (mgreg_t));
922 scanned_registers += sizeof (mgreg_t);
924 if (new_reg_locations [i]) {
925 DEBUG (printf ("\tscan saved reg location %p.\n", new_reg_locations [i]));
926 mono_gc_conservatively_scan_area (new_reg_locations [i], new_reg_locations [i] + sizeof (mgreg_t));
927 scanned_registers += sizeof (mgreg_t);
931 if (stack_limit < stack_end) {
932 DEBUG (printf ("\tscan remaining stack %p-%p (%d).\n", stack_limit, stack_end, (int)(stack_end - stack_limit)));
933 mono_gc_conservatively_scan_area (stack_limit, stack_end);
934 stats.scanned_native += stack_end - stack_limit;
937 DEBUG (printf ("Marked %d bytes, p=%d,c=%d out of %d.\n", scanned, scanned_precisely, scanned_conservatively, (int)(stack_end - stack_start)));
939 stats.scanned_stacks += stack_end - stack_start;
940 stats.scanned += scanned;
941 stats.scanned_precisely += scanned_precisely;
942 stats.scanned_conservatively += scanned_conservatively;
943 stats.scanned_registers += scanned_registers;
945 //mono_gc_conservatively_scan_area (stack_start, stack_end);
951 * Mark a thread stack precisely based on information saved during the conservative
955 precise_pass (TlsData *tls, guint8 *stack_start, guint8 *stack_end)
964 for (findex = 0; findex < tls->nframes; findex ++) {
965 /* Load information saved by the !precise pass */
966 fi = &tls->frames [findex];
967 frame_start = stack_start + fi->frame_start_offset;
970 * FIXME: Add a function to mark using a bitmap, to avoid doing a
971 * call for each object.
974 /* Mark stack slots */
976 guint8 *ref_bitmap = fi->bitmap;
979 for (i = 0; i < fi->nslots; ++i) {
980 MonoObject **ptr = (MonoObject**)(frame_start + (i * sizeof (mgreg_t)));
982 live = ref_bitmap [i / 8] & (1 << (i % 8));
985 MonoObject *obj = *ptr;
987 DEBUG (printf ("\tref %s0x%x(fp)=%p: %p ->", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, obj));
988 *ptr = mono_gc_scan_object (obj);
989 DEBUG (printf (" %p.\n", *ptr));
991 DEBUG (printf ("\tref %s0x%x(fp)=%p: %p.\n", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, obj));
996 * This is disabled because the pointer takes up a lot of space.
997 * Stack slots might be shared between ref and non-ref variables ?
999 if (map->ref_slots [i / 8] & (1 << (i % 8))) {
1000 DEBUG (printf ("\tref %s0x%x(fp)=%p: dead (%p)\n", (guint8*)ptr >= (guint8*)fi->fp ? "" : "-", ABS ((int)((gssize)ptr - (gssize)fi->fp)), ptr, *ptr));
1002 * Fail fast if the live range is incorrect, and
1003 * the JITted code tries to access this object
1012 /* Mark registers */
1015 * Registers are different from stack slots, they have no address where they
1016 * are stored. Instead, some frame below this frame in the stack saves them
1017 * in its prolog to the stack. We can mark this location precisely.
1019 for (i = 0; i < fi->nreg_locations; ++i) {
1021 * reg_locations [i] contains the address of the stack slot where
1022 * a reg was last saved, so mark that slot.
1024 MonoObject **ptr = (MonoObject**)((guint8*)stack_start + fi->reg_locations [i]);
1025 MonoObject *obj = *ptr;
1028 DEBUG (printf ("\treg %s saved at %p: %p ->", mono_arch_regname (fi->regs [i]), ptr, obj));
1029 *ptr = mono_gc_scan_object (obj);
1030 DEBUG (printf (" %p.\n", *ptr));
1032 DEBUG (printf ("\treg %s saved at %p: %p", mono_arch_regname (fi->regs [i]), ptr, obj));
1041 * This is called by the GC twice to mark a thread stack. PRECISE is FALSE at the first
1042 * call, and TRUE at the second. USER_DATA points to a TlsData
1043 * structure filled up by thread_suspend_func.
1046 thread_mark_func (gpointer user_data, guint8 *stack_start, guint8 *stack_end, gboolean precise)
1048 TlsData *tls = user_data;
1050 DEBUG (printf ("*** %s stack marking %p-%p ***\n", precise ? "Precise" : "Conservative", stack_start, stack_end));
1053 conservative_pass (tls, stack_start, stack_end);
1055 precise_pass (tls, stack_start, stack_end);
1059 mini_gc_init_gc_map (MonoCompile *cfg)
1061 if (COMPILE_LLVM (cfg))
1065 /* Debugging support */
1067 static int precise_count;
1070 if (getenv ("MONO_GCMAP_COUNT")) {
1071 if (precise_count == atoi (getenv ("MONO_GCMAP_COUNT")))
1072 printf ("LAST: %s\n", mono_method_full_name (cfg->method, TRUE));
1073 if (precise_count > atoi (getenv ("MONO_GCMAP_COUNT")))
1079 cfg->compute_gc_maps = TRUE;
1081 cfg->gc_info = mono_mempool_alloc0 (cfg->mempool, sizeof (MonoCompileGC));
1085 * mini_gc_set_slot_type_from_fp:
1087 * Set the GC slot type of the stack slot identified by SLOT_OFFSET, which should be
1088 * relative to the frame pointer. By default, all stack slots are type PIN, so there is no
1089 * need to call this function for those slots.
1092 mini_gc_set_slot_type_from_fp (MonoCompile *cfg, int slot_offset, GCSlotType type)
1094 MonoCompileGC *gcfg = (MonoCompileGC*)cfg->gc_info;
1096 if (!cfg->compute_gc_maps)
1099 g_assert (slot_offset % sizeof (mgreg_t) == 0);
1101 gcfg->stack_slots_from_fp = g_slist_prepend_mempool (cfg->mempool, gcfg->stack_slots_from_fp, GINT_TO_POINTER (((slot_offset) << 16) | type));
1105 * mini_gc_set_slot_type_from_cfa:
1107 * Set the GC slot type of the stack slot identified by SLOT_OFFSET, which should be
1108 * relative to the DWARF CFA value. This should be called from mono_arch_emit_prolog ().
1109 * If type is STACK_REF, the slot is assumed to be live from the end of the prolog until
1110 * the end of the method. By default, all stack slots are type PIN, so there is no need to
1111 * call this function for those slots.
1114 mini_gc_set_slot_type_from_cfa (MonoCompile *cfg, int slot_offset, GCSlotType type)
1116 MonoCompileGC *gcfg = (MonoCompileGC*)cfg->gc_info;
1117 int slot = - (slot_offset / sizeof (mgreg_t));
1119 if (!cfg->compute_gc_maps)
1122 g_assert (slot_offset <= 0);
1123 g_assert (slot_offset % sizeof (mgreg_t) == 0);
1125 gcfg->stack_slots_from_cfa = g_slist_prepend_mempool (cfg->mempool, gcfg->stack_slots_from_cfa, GUINT_TO_POINTER (((slot) << 16) | type));
1129 fp_offset_to_slot (MonoCompile *cfg, int offset)
1131 MonoCompileGC *gcfg = cfg->gc_info;
1133 return (offset - gcfg->min_offset) / sizeof (mgreg_t);
1137 slot_to_fp_offset (MonoCompile *cfg, int slot)
1139 MonoCompileGC *gcfg = cfg->gc_info;
1141 return (slot * sizeof (mgreg_t)) + gcfg->min_offset;
1145 set_slot (MonoCompileGC *gcfg, int slot, int callsite_index, GCSlotType type)
1147 g_assert (slot >= 0 && slot < gcfg->nslots);
1149 if (type == SLOT_PIN) {
1150 clear_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1151 set_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1152 } else if (type == SLOT_REF) {
1153 set_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1154 clear_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1155 } else if (type == SLOT_NOREF) {
1156 clear_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1157 clear_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, callsite_index, slot);
1162 set_slot_everywhere (MonoCompileGC *gcfg, int slot, GCSlotType type)
1166 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
1167 set_slot (gcfg, slot, cindex, type);
1171 set_slot_in_range (MonoCompileGC *gcfg, int slot, int from, int to, GCSlotType type)
1175 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
1176 int callsite_offset = gcfg->callsites [cindex]->pc_offset;
1177 if (callsite_offset >= from && callsite_offset < to)
1178 set_slot (gcfg, slot, cindex, type);
1183 set_reg_slot (MonoCompileGC *gcfg, int slot, int callsite_index, GCSlotType type)
1185 g_assert (slot >= 0 && slot < gcfg->nregs);
1187 if (type == SLOT_PIN) {
1188 clear_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1189 set_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1190 } else if (type == SLOT_REF) {
1191 set_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1192 clear_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1193 } else if (type == SLOT_NOREF) {
1194 clear_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1195 clear_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, callsite_index, slot);
1200 set_reg_slot_everywhere (MonoCompileGC *gcfg, int slot, GCSlotType type)
1204 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
1205 set_reg_slot (gcfg, slot, cindex, type);
1209 set_reg_slot_in_range (MonoCompileGC *gcfg, int slot, int from, int to, GCSlotType type)
1213 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
1214 int callsite_offset = gcfg->callsites [cindex]->pc_offset;
1215 if (callsite_offset >= from && callsite_offset < to)
1216 set_reg_slot (gcfg, slot, cindex, type);
1221 process_spill_slots (MonoCompile *cfg)
1223 MonoCompileGC *gcfg = cfg->gc_info;
1228 /* Mark all ref/pin spill slots as NOREF by default outside of their live range */
1229 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
1230 for (l = bb->spill_slot_defs; l; l = l->next) {
1231 MonoInst *def = l->data;
1232 int spill_slot = def->inst_c0;
1233 int bank = def->inst_c1;
1234 int offset = cfg->spill_info [bank][spill_slot].offset;
1235 int slot = fp_offset_to_slot (cfg, offset);
1237 if (bank == MONO_REG_INT_MP || bank == MONO_REG_INT_REF)
1238 set_slot_everywhere (gcfg, slot, SLOT_NOREF);
1242 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
1243 for (l = bb->spill_slot_defs; l; l = l->next) {
1244 MonoInst *def = l->data;
1245 int spill_slot = def->inst_c0;
1246 int bank = def->inst_c1;
1247 int offset = cfg->spill_info [bank][spill_slot].offset;
1248 int slot = fp_offset_to_slot (cfg, offset);
1251 if (bank == MONO_REG_INT_MP)
1257 * Extend the live interval for the GC tracked spill slots
1258 * defined in this bblock.
1259 * FIXME: This is not needed.
1261 set_slot_in_range (gcfg, slot, def->backend.pc_offset, bb->native_offset + bb->native_length, type);
1263 if (cfg->verbose_level > 1)
1264 printf ("\t%s spill slot at %s0x%x(fp) (slot = %d)\n", slot_type_to_string (type), offset >= 0 ? "" : "-", ABS (offset), slot);
1268 /* Set fp spill slots to NOREF */
1269 for (i = 0; i < cfg->spill_info_len [MONO_REG_DOUBLE]; ++i) {
1270 int offset = cfg->spill_info [MONO_REG_DOUBLE][i].offset;
1276 slot = fp_offset_to_slot (cfg, offset);
1278 set_slot_everywhere (gcfg, slot, SLOT_NOREF);
1280 if (cfg->verbose_level > 1)
1281 printf ("\tfp spill slot at %s0x%x(fp) (slot = %d)\n", offset >= 0 ? "" : "-", ABS (offset), slot);
1284 /* Set int spill slots to NOREF */
1285 for (i = 0; i < cfg->spill_info_len [MONO_REG_INT]; ++i) {
1286 int offset = cfg->spill_info [MONO_REG_INT][i].offset;
1292 slot = fp_offset_to_slot (cfg, offset);
1294 set_slot_everywhere (gcfg, slot, SLOT_NOREF);
1295 if (cfg->verbose_level > 1)
1296 printf ("\tint spill slot at %s0x%x(fp) (slot = %d)\n", offset >= 0 ? "" : "-", ABS (offset), slot);
1301 * process_other_slots:
1303 * Process stack slots registered using mini_gc_set_slot_type_... ().
1306 process_other_slots (MonoCompile *cfg)
1308 MonoCompileGC *gcfg = cfg->gc_info;
1311 /* Relative to the CFA */
1312 for (l = gcfg->stack_slots_from_cfa; l; l = l->next) {
1313 guint data = GPOINTER_TO_UINT (l->data);
1314 int cfa_slot = data >> 16;
1315 GCSlotType type = data & 0xff;
1319 * Map the cfa relative slot to an fp relative slot.
1320 * slot_addr == cfa - <cfa_slot>*4/8
1321 * fp + cfa_offset == cfa
1322 * -> slot_addr == fp + (cfa_offset - <cfa_slot>*4/8)
1324 slot = (cfg->cfa_offset / sizeof (mgreg_t)) - cfa_slot - (gcfg->min_offset / sizeof (mgreg_t));
1326 set_slot_everywhere (gcfg, slot, type);
1328 if (cfg->verbose_level > 1) {
1329 int fp_offset = slot_to_fp_offset (cfg, slot);
1330 if (type == SLOT_NOREF)
1331 printf ("\tnoref slot at %s0x%x(fp) (slot = %d) (cfa - 0x%x)\n", fp_offset >= 0 ? "" : "-", ABS (fp_offset), slot, (int)(cfa_slot * sizeof (mgreg_t)));
1335 /* Relative to the FP */
1336 for (l = gcfg->stack_slots_from_fp; l; l = l->next) {
1337 gint data = GPOINTER_TO_INT (l->data);
1338 int offset = data >> 16;
1339 GCSlotType type = data & 0xff;
1342 slot = fp_offset_to_slot (cfg, offset);
1344 set_slot_everywhere (gcfg, slot, type);
1346 /* Liveness for these slots is handled by process_spill_slots () */
1348 if (cfg->verbose_level > 1) {
1349 if (type == SLOT_REF)
1350 printf ("\tref slot at fp+0x%x (slot = %d)\n", offset, slot);
1356 process_variables (MonoCompile *cfg)
1358 MonoCompileGC *gcfg = cfg->gc_info;
1359 MonoMethodSignature *sig = mono_method_signature (cfg->method);
1360 int i, locals_min_slot, locals_max_slot, cindex;
1364 int locals_min_offset = gcfg->locals_min_offset;
1365 int locals_max_offset = gcfg->locals_max_offset;
1367 /* Slots for locals are NOREF by default */
1368 locals_min_slot = (locals_min_offset - gcfg->min_offset) / sizeof (mgreg_t);
1369 locals_max_slot = (locals_max_offset - gcfg->min_offset) / sizeof (mgreg_t);
1370 for (i = locals_min_slot; i < locals_max_slot; ++i) {
1371 set_slot_everywhere (gcfg, i, SLOT_NOREF);
1375 * Compute the offset where variables are initialized in the first bblock, if any.
1377 pc_offsets = g_new0 (int, cfg->next_vreg);
1379 bb = cfg->bb_entry->next_bb;
1380 MONO_BB_FOR_EACH_INS (bb, tmp) {
1381 if (tmp->opcode == OP_GC_LIVENESS_DEF) {
1382 int vreg = tmp->inst_c1;
1383 if (pc_offsets [vreg] == 0) {
1384 g_assert (tmp->backend.pc_offset > 0);
1385 pc_offsets [vreg] = tmp->backend.pc_offset;
1391 * Stack slots holding arguments are initialized in the prolog.
1392 * This means we can treat them alive for the whole method.
1394 for (i = 0; i < cfg->num_varinfo; i++) {
1395 MonoInst *ins = cfg->varinfo [i];
1396 MonoType *t = ins->inst_vtype;
1399 gboolean byref, is_this = FALSE;
1400 gboolean is_arg = i < cfg->locals_start;
1402 if (ins == cfg->ret)
1405 vmv = MONO_VARINFO (cfg, i);
1407 /* For some reason, 'this' is byref */
1408 if (sig->hasthis && ins == cfg->args [0] && !cfg->method->klass->valuetype) {
1409 t = &cfg->method->klass->byval_arg;
1415 if (ins->opcode == OP_REGVAR) {
1417 GCSlotType slot_type;
1419 t = mini_type_get_underlying_type (NULL, t);
1422 g_assert (hreg < MONO_MAX_IREGS);
1424 // FIXME: Add back this check
1426 if (is_arg && gcfg->reg_live_intervals [hreg]) {
1428 * FIXME: This argument shares a hreg with a local, we can't add the whole
1429 * method as a live interval, since it would overlap with the locals
1437 slot_type = SLOT_PIN;
1439 slot_type = MONO_TYPE_IS_REFERENCE (t) ? SLOT_REF : SLOT_NOREF;
1442 /* Live for the whole method */
1443 set_reg_slot_everywhere (gcfg, hreg, slot_type);
1445 if (slot_type == SLOT_PIN) {
1446 /* These have no live interval, be conservative */
1447 set_reg_slot_everywhere (gcfg, hreg, slot_type);
1450 * Unlike variables allocated to the stack, we generate liveness info
1451 * for noref vars in registers in mono_spill_global_vars (), because
1452 * knowing that a register doesn't contain a ref allows us to mark its save
1453 * locations precisely.
1455 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
1456 if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
1457 set_reg_slot (gcfg, hreg, cindex, slot_type);
1461 if (cfg->verbose_level > 1) {
1462 printf ("\t%s %sreg %s(R%d)\n", slot_type_to_string (slot_type), is_arg ? "arg " : "", mono_arch_regname (hreg), vmv->vreg);
1468 if (ins->opcode != OP_REGOFFSET)
1471 if (ins->inst_offset % sizeof (mgreg_t) != 0)
1474 if (is_arg && ins->inst_offset >= gcfg->max_offset)
1475 /* In parent frame */
1478 pos = fp_offset_to_slot (cfg, ins->inst_offset);
1480 if (is_arg && ins->flags & MONO_INST_IS_DEAD) {
1481 /* These do not get stored in the prolog */
1482 set_slot_everywhere (gcfg, pos, SLOT_NOREF);
1484 if (cfg->verbose_level > 1) {
1485 printf ("\tdead arg at fp%s0x%x (slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "+", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, pos, mono_type_full_name (ins->inst_vtype));
1490 if (MONO_TYPE_ISSTRUCT (t)) {
1492 gsize *bitmap = NULL;
1493 gboolean pin = FALSE;
1497 if (ins->backend.is_pinvoke)
1498 size = mono_class_native_size (ins->klass, NULL);
1500 size = mono_class_value_size (ins->klass, NULL);
1501 size_in_slots = ALIGN_TO (size, sizeof (mgreg_t)) / sizeof (mgreg_t);
1503 if (!ins->klass->has_references) {
1505 for (j = 0; j < size_in_slots; ++j)
1506 set_slot_everywhere (gcfg, pos + j, SLOT_NOREF);
1511 if (ins->klass->generic_container || mono_class_is_open_constructed_type (t)) {
1512 /* FIXME: Generic sharing */
1515 mono_class_compute_gc_descriptor (ins->klass);
1517 bitmap = mono_gc_get_bitmap_for_descr (ins->klass->gc_descr, &numbits);
1521 * Most vtypes are marked volatile because of the LDADDR instructions,
1522 * and they have no liveness information since they are decomposed
1523 * before the liveness pass. We emit OP_GC_LIVENESS_DEF instructions for
1524 * them during VZERO decomposition.
1526 if (!pc_offsets [vmv->vreg])
1530 if (ins->backend.is_pinvoke)
1534 if (pc_offsets [vmv->vreg]) {
1535 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex) {
1536 if (gcfg->callsites [cindex]->pc_offset > pc_offsets [vmv->vreg]) {
1537 for (j = 0; j < numbits; ++j) {
1538 if (bitmap [j / GC_BITS_PER_WORD] & ((gsize)1 << (j % GC_BITS_PER_WORD))) {
1539 /* The descriptor is for the boxed object */
1540 set_slot (gcfg, (pos + j - (sizeof (MonoObject) / sizeof (gpointer))), cindex, pin ? SLOT_PIN : SLOT_REF);
1547 for (j = 0; j < size_in_slots; ++j) {
1548 set_slot_everywhere (gcfg, pos + j, SLOT_PIN);
1554 if (cfg->verbose_level > 1) {
1555 printf ("\tvtype R%d at fp+0x%x-0x%x: %s\n", vmv->vreg, (int)ins->inst_offset, (int)(ins->inst_offset + (size / sizeof (mgreg_t))), mono_type_full_name (ins->inst_vtype));
1561 if (!is_arg && (ins->inst_offset < gcfg->min_offset || ins->inst_offset >= gcfg->max_offset))
1562 /* Vret addr etc. */
1567 set_slot_everywhere (gcfg, pos, SLOT_PIN);
1569 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
1570 if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
1571 set_slot (gcfg, pos, cindex, SLOT_PIN);
1573 if (cfg->verbose_level > 1)
1574 printf ("\tbyref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
1579 * This is currently disabled, but could be enabled to debug crashes.
1582 if (t->type == MONO_TYPE_I) {
1584 * Variables created in mono_handle_global_vregs have type I, but they
1585 * could hold GC refs since the vregs they were created from might not been
1586 * marked as holding a GC ref. So be conservative.
1588 set_slot_everywhere (gcfg, pos, SLOT_PIN);
1593 t = mini_type_get_underlying_type (NULL, t);
1595 if (!MONO_TYPE_IS_REFERENCE (t)) {
1596 set_slot_everywhere (gcfg, pos, SLOT_NOREF);
1597 if (cfg->verbose_level > 1)
1598 printf ("\tnoref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
1602 /* 'this' is marked INDIRECT for gshared methods */
1603 if (ins->flags & (MONO_INST_VOLATILE | MONO_INST_INDIRECT) && !is_this) {
1605 * For volatile variables, treat them alive from the point they are
1606 * initialized in the first bblock until the end of the method.
1609 set_slot_everywhere (gcfg, pos, SLOT_REF);
1610 } else if (pc_offsets [vmv->vreg]) {
1611 set_slot_in_range (gcfg, pos, 0, pc_offsets [vmv->vreg], SLOT_PIN);
1612 set_slot_in_range (gcfg, pos, pc_offsets [vmv->vreg], cfg->code_size, SLOT_REF);
1614 set_slot_everywhere (gcfg, pos, SLOT_PIN);
1616 if (cfg->verbose_level > 1)
1617 printf ("\tvolatile ref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
1622 /* Live for the whole method */
1623 set_slot_everywhere (gcfg, pos, SLOT_REF);
1625 for (cindex = 0; cindex < gcfg->ncallsites; ++cindex)
1626 if (gcfg->callsites [cindex]->liveness [i / 8] & (1 << (i % 8)))
1627 set_slot (gcfg, pos, cindex, SLOT_REF);
1630 if (cfg->verbose_level > 1) {
1631 printf ("\tref at %s0x%x(fp) (R%d, slot = %d): %s\n", ins->inst_offset < 0 ? "-" : "", (ins->inst_offset < 0) ? -(int)ins->inst_offset : (int)ins->inst_offset, vmv->vreg, pos, mono_type_full_name (ins->inst_vtype));
1635 g_free (pc_offsets);
1639 sp_offset_to_fp_offset (MonoCompile *cfg, int sp_offset)
1642 * Convert a sp relative offset to a slot index. This is
1643 * platform specific.
1646 /* fp = sp + offset */
1647 g_assert (cfg->frame_reg == AMD64_RBP);
1648 return (- cfg->arch.sp_fp_offset + sp_offset);
1656 type_to_gc_slot_type (MonoType *t)
1660 t = mini_type_get_underlying_type (NULL, t);
1661 if (MONO_TYPE_IS_REFERENCE (t))
1664 if (MONO_TYPE_ISSTRUCT (t)) {
1665 MonoClass *klass = mono_class_from_mono_type (t);
1666 if (!klass->has_references) {
1678 process_param_area_slots (MonoCompile *cfg)
1680 MonoCompileGC *gcfg = cfg->gc_info;
1685 * These slots are used for passing parameters during calls. They are sp relative, not
1686 * fp relative, so they are harder to handle.
1688 if (cfg->flags & MONO_CFG_HAS_ALLOCA)
1689 /* The distance between fp and sp is not constant */
1692 is_param = mono_mempool_alloc0 (cfg->mempool, gcfg->nslots * sizeof (gboolean));
1694 for (i = 0; i < gcfg->ncallsites; ++i) {
1695 GCCallSite *callsite = gcfg->callsites [i];
1698 for (l = callsite->param_slots; l; l = l->next) {
1699 MonoInst *def = l->data;
1700 int sp_offset = def->inst_offset;
1701 int fp_offset = sp_offset_to_fp_offset (cfg, sp_offset);
1702 int slot = fp_offset_to_slot (cfg, fp_offset);
1704 g_assert (slot >= 0 && slot < gcfg->nslots);
1705 is_param [slot] = TRUE;
1709 /* All param area slots are noref by default */
1710 for (i = 0; i < gcfg->nslots; ++i) {
1712 set_slot_everywhere (gcfg, i, SLOT_NOREF);
1715 for (i = 0; i < gcfg->ncallsites; ++i) {
1716 GCCallSite *callsite = gcfg->callsites [i];
1719 for (l = callsite->param_slots; l; l = l->next) {
1720 MonoInst *def = l->data;
1721 MonoType *t = def->inst_vtype;
1722 int sp_offset = def->inst_offset;
1723 int fp_offset = sp_offset_to_fp_offset (cfg, sp_offset);
1724 int slot = fp_offset_to_slot (cfg, fp_offset);
1725 GCSlotType type = type_to_gc_slot_type (t);
1727 /* The slot is live between the def instruction and the call */
1728 set_slot_in_range (gcfg, slot, def->backend.pc_offset, callsite->pc_offset + 1, type);
1729 if (cfg->verbose_level > 1)
1730 printf ("\t%s param area slot at %s0x%x(fp)=0x%x(sp) (slot = %d) [0x%x-0x%x]\n", slot_type_to_string (type), fp_offset >= 0 ? "+" : "-", ABS (fp_offset), sp_offset, slot, def->backend.pc_offset, callsite->pc_offset + 1);
1736 process_finally_clauses (MonoCompile *cfg)
1738 MonoCompileGC *gcfg = cfg->gc_info;
1739 GCCallSite **callsites;
1741 gboolean has_finally;
1742 int i, j, nslots, nregs;
1744 ncallsites = gcfg->ncallsites;
1745 nslots = gcfg->nslots;
1746 nregs = gcfg->nregs;
1747 callsites = gcfg->callsites;
1750 * The calls to the finally clauses don't show up in the cfg. See
1751 * test_0_liveness_8 ().
1752 * Variables accessed inside the finally clause are already marked VOLATILE by
1753 * mono_liveness_handle_exception_clauses (). Variables not accessed inside the finally clause have
1754 * correct liveness outside the finally clause. So mark them PIN inside the finally clauses.
1756 has_finally = FALSE;
1757 for (i = 0; i < cfg->header->num_clauses; ++i) {
1758 MonoExceptionClause *clause = &cfg->header->clauses [i];
1760 if (clause->flags == MONO_EXCEPTION_CLAUSE_FINALLY) {
1765 if (cfg->verbose_level > 1)
1766 printf ("\tMethod has finally clauses, pessimizing live ranges.\n");
1767 for (j = 0; j < ncallsites; ++j) {
1768 MonoBasicBlock *bb = callsites [j]->bb;
1769 MonoExceptionClause *clause;
1770 gboolean is_in_finally = FALSE;
1772 for (i = 0; i < cfg->header->num_clauses; ++i) {
1773 clause = &cfg->header->clauses [i];
1775 if (MONO_OFFSET_IN_HANDLER (clause, bb->real_offset)) {
1776 if (clause->flags == MONO_EXCEPTION_CLAUSE_FINALLY) {
1777 is_in_finally = TRUE;
1783 if (is_in_finally) {
1784 for (i = 0; i < nslots; ++i)
1785 set_slot (gcfg, i, j, SLOT_PIN);
1786 for (i = 0; i < nregs; ++i)
1787 set_reg_slot (gcfg, i, j, SLOT_PIN);
1794 compute_frame_size (MonoCompile *cfg)
1796 int i, locals_min_offset, locals_max_offset, cfa_min_offset, cfa_max_offset;
1797 int min_offset, max_offset;
1798 MonoCompileGC *gcfg = cfg->gc_info;
1799 MonoMethodSignature *sig = mono_method_signature (cfg->method);
1802 /* Compute min/max offsets from the fp */
1806 locals_min_offset = ALIGN_TO (cfg->locals_min_stack_offset, sizeof (mgreg_t));
1807 locals_max_offset = cfg->locals_max_stack_offset;
1809 /* min/max stack offset needs to be computed in mono_arch_allocate_vars () */
1813 locals_min_offset = ALIGN_TO (locals_min_offset, sizeof (mgreg_t));
1814 locals_max_offset = ALIGN_TO (locals_max_offset, sizeof (mgreg_t));
1816 min_offset = locals_min_offset;
1817 max_offset = locals_max_offset;
1820 for (i = 0; i < sig->param_count + sig->hasthis; ++i) {
1821 MonoInst *ins = cfg->args [i];
1823 if (ins->opcode == OP_REGOFFSET)
1824 min_offset = MIN (min_offset, ins->inst_offset);
1828 g_assert (cfg->frame_reg == cfg->cfa_reg);
1829 g_assert (cfg->cfa_offset > 0);
1831 cfa_max_offset = cfg->cfa_offset;
1833 min_offset = MIN (min_offset, cfa_min_offset);
1834 max_offset = MAX (max_offset, cfa_max_offset);
1836 /* Fp relative slots */
1837 for (l = gcfg->stack_slots_from_fp; l; l = l->next) {
1838 gint data = GPOINTER_TO_INT (l->data);
1839 int offset = data >> 16;
1841 min_offset = MIN (min_offset, offset);
1845 if (!(cfg->flags & MONO_CFG_HAS_SPILLUP)) {
1846 int stack_offset = ALIGN_TO (cfg->stack_offset, sizeof (mgreg_t));
1847 min_offset = MIN (min_offset, (-stack_offset));
1850 /* Param area slots */
1852 min_offset = MIN (min_offset, -cfg->arch.sp_fp_offset);
1855 gcfg->min_offset = min_offset;
1856 gcfg->max_offset = max_offset;
1857 gcfg->locals_min_offset = locals_min_offset;
1858 gcfg->locals_max_offset = locals_max_offset;
1862 init_gcfg (MonoCompile *cfg)
1864 int i, nregs, nslots;
1865 MonoCompileGC *gcfg = cfg->gc_info;
1866 GCCallSite **callsites;
1875 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
1876 ncallsites += g_slist_length (bb->gc_callsites);
1878 callsites = mono_mempool_alloc0 (cfg->mempool, ncallsites * sizeof (GCCallSite*));
1880 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
1881 for (l = bb->gc_callsites; l; l = l->next)
1882 callsites [i++] = l->data;
1885 /* The callsites should already be ordered by pc offset */
1886 for (i = 1; i < ncallsites; ++i)
1887 g_assert (callsites [i - 1]->pc_offset < callsites [i]->pc_offset);
1890 * The stack frame looks like this:
1892 * <fp + max_offset> == cfa -> <end of previous frame>
1893 * <other stack slots>
1895 * <other stack slots>
1896 * fp + min_offset ->
1901 if (cfg->verbose_level > 1)
1902 printf ("GC Map for %s: 0x%x-0x%x\n", mono_method_full_name (cfg->method, TRUE), gcfg->min_offset, gcfg->max_offset);
1904 nslots = (gcfg->max_offset - gcfg->min_offset) / sizeof (mgreg_t);
1907 gcfg->nslots = nslots;
1908 gcfg->nregs = nregs;
1909 gcfg->callsites = callsites;
1910 gcfg->ncallsites = ncallsites;
1911 gcfg->stack_bitmap_width = ALIGN_TO (nslots, 8) / 8;
1912 gcfg->reg_bitmap_width = ALIGN_TO (nregs, 8) / 8;
1913 gcfg->stack_ref_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->stack_bitmap_width * ncallsites);
1914 gcfg->stack_pin_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->stack_bitmap_width * ncallsites);
1915 gcfg->reg_ref_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->reg_bitmap_width * ncallsites);
1916 gcfg->reg_pin_bitmap = mono_mempool_alloc0 (cfg->mempool, gcfg->reg_bitmap_width * ncallsites);
1918 /* All slots start out as PIN */
1919 memset (gcfg->stack_pin_bitmap, 0xff, gcfg->stack_bitmap_width * ncallsites);
1920 for (i = 0; i < nregs; ++i) {
1922 * By default, registers are NOREF.
1923 * It is possible for a callee to save them before being defined in this method,
1924 * but the saved value is dead too, so it doesn't need to be marked.
1926 if ((cfg->used_int_regs & (1 << i)))
1927 set_reg_slot_everywhere (gcfg, i, SLOT_NOREF);
1932 create_map (MonoCompile *cfg)
1935 int i, j, nregs, nslots, nref_regs, npin_regs, alloc_size, bitmaps_size, bitmaps_offset;
1937 int stack_bitmap_width, stack_bitmap_size, reg_ref_bitmap_width, reg_ref_bitmap_size;
1938 int reg_pin_bitmap_width, reg_pin_bitmap_size, bindex;
1940 gboolean has_ref_slots, has_pin_slots, has_ref_regs, has_pin_regs;
1941 MonoCompileGC *gcfg = cfg->gc_info;
1942 GCCallSite **callsites;
1944 guint8 *bitmap, *bitmaps;
1945 guint32 reg_ref_mask, reg_pin_mask;
1947 ncallsites = gcfg->ncallsites;
1948 nslots = gcfg->nslots;
1949 nregs = gcfg->nregs;
1950 callsites = gcfg->callsites;
1953 * Compute the real size of the bitmap i.e. ignore NOREF columns at the beginning and at
1954 * the end. Also, compute whenever the map needs ref/pin bitmaps, and collect stats.
1956 has_ref_slots = FALSE;
1957 has_pin_slots = FALSE;
1960 memset (ntypes, 0, sizeof (ntypes));
1961 for (i = 0; i < nslots; ++i) {
1962 gboolean has_ref = FALSE;
1963 gboolean has_pin = FALSE;
1965 for (j = 0; j < ncallsites; ++j) {
1966 if (get_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, j, i))
1968 if (get_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, j, i))
1973 has_ref_slots = TRUE;
1975 has_pin_slots = TRUE;
1978 ntypes [SLOT_REF] ++;
1980 ntypes [SLOT_PIN] ++;
1982 ntypes [SLOT_NOREF] ++;
1984 if (has_ref || has_pin) {
1991 start = end = nslots;
1993 g_assert (start != -1);
1994 g_assert (start < end);
1997 has_ref_regs = FALSE;
1998 has_pin_regs = FALSE;
2003 for (i = 0; i < nregs; ++i) {
2004 gboolean has_ref = FALSE;
2005 gboolean has_pin = FALSE;
2007 if (!(cfg->used_int_regs & (1 << i)))
2010 for (j = 0; j < ncallsites; ++j) {
2011 if (get_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, j, i)) {
2016 for (j = 0; j < ncallsites; ++j) {
2017 if (get_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, j, i)) {
2024 reg_ref_mask |= (1 << i);
2025 has_ref_regs = TRUE;
2029 reg_pin_mask |= (1 << i);
2030 has_pin_regs = TRUE;
2035 if (cfg->verbose_level > 1)
2036 printf ("Slots: %d Start: %d End: %d Refs: %d NoRefs: %d Pin: %d Callsites: %d\n", nslots, start, end, ntypes [SLOT_REF], ntypes [SLOT_NOREF], ntypes [SLOT_PIN], ncallsites);
2038 /* Create the GC Map */
2040 stack_bitmap_width = ALIGN_TO (end - start, 8) / 8;
2041 stack_bitmap_size = stack_bitmap_width * ncallsites;
2042 reg_ref_bitmap_width = ALIGN_TO (nref_regs, 8) / 8;
2043 reg_ref_bitmap_size = reg_ref_bitmap_width * ncallsites;
2044 reg_pin_bitmap_width = ALIGN_TO (npin_regs, 8) / 8;
2045 reg_pin_bitmap_size = reg_pin_bitmap_width * ncallsites;
2046 bitmaps_size = (has_ref_slots ? stack_bitmap_size : 0) + (has_pin_slots ? stack_bitmap_size : 0) + (has_ref_regs ? reg_ref_bitmap_size : 0) + (has_pin_regs ? reg_pin_bitmap_size : 0);
2048 map = mono_mempool_alloc0 (cfg->mempool, sizeof (GCMap));
2050 map->frame_reg = cfg->frame_reg;
2051 map->start_offset = gcfg->min_offset;
2052 map->end_offset = gcfg->min_offset + (nslots * sizeof (mgreg_t));
2053 map->map_offset = start * sizeof (mgreg_t);
2054 map->nslots = end - start;
2055 map->has_ref_slots = has_ref_slots;
2056 map->has_pin_slots = has_pin_slots;
2057 map->has_ref_regs = has_ref_regs;
2058 map->has_pin_regs = has_pin_regs;
2059 g_assert (nregs < 32);
2060 map->used_int_regs = cfg->used_int_regs;
2061 map->reg_ref_mask = reg_ref_mask;
2062 map->reg_pin_mask = reg_pin_mask;
2063 map->nref_regs = nref_regs;
2064 map->npin_regs = npin_regs;
2066 bitmaps = mono_mempool_alloc0 (cfg->mempool, bitmaps_size);
2069 if (has_ref_slots) {
2070 map->stack_ref_bitmap_offset = bitmaps_offset;
2071 bitmaps_offset += stack_bitmap_size;
2073 bitmap = &bitmaps [map->stack_ref_bitmap_offset];
2074 for (i = 0; i < nslots; ++i) {
2075 for (j = 0; j < ncallsites; ++j) {
2076 if (get_bit (gcfg->stack_ref_bitmap, gcfg->stack_bitmap_width, j, i))
2077 set_bit (bitmap, stack_bitmap_width, j, i - start);
2081 if (has_pin_slots) {
2082 map->stack_pin_bitmap_offset = bitmaps_offset;
2083 bitmaps_offset += stack_bitmap_size;
2085 bitmap = &bitmaps [map->stack_pin_bitmap_offset];
2086 for (i = 0; i < nslots; ++i) {
2087 for (j = 0; j < ncallsites; ++j) {
2088 if (get_bit (gcfg->stack_pin_bitmap, gcfg->stack_bitmap_width, j, i))
2089 set_bit (bitmap, stack_bitmap_width, j, i - start);
2094 map->reg_ref_bitmap_offset = bitmaps_offset;
2095 bitmaps_offset += reg_ref_bitmap_size;
2097 bitmap = &bitmaps [map->reg_ref_bitmap_offset];
2099 for (i = 0; i < nregs; ++i) {
2100 if (reg_ref_mask & (1 << i)) {
2101 for (j = 0; j < ncallsites; ++j) {
2102 if (get_bit (gcfg->reg_ref_bitmap, gcfg->reg_bitmap_width, j, i))
2103 set_bit (bitmap, reg_ref_bitmap_width, j, bindex);
2110 map->reg_pin_bitmap_offset = bitmaps_offset;
2111 bitmaps_offset += reg_pin_bitmap_size;
2113 bitmap = &bitmaps [map->reg_pin_bitmap_offset];
2115 for (i = 0; i < nregs; ++i) {
2116 if (reg_pin_mask & (1 << i)) {
2117 for (j = 0; j < ncallsites; ++j) {
2118 if (get_bit (gcfg->reg_pin_bitmap, gcfg->reg_bitmap_width, j, i))
2119 set_bit (bitmap, reg_pin_bitmap_width, j, bindex);
2127 map->ncallsites = ncallsites;
2128 if (cfg->code_len < 256)
2129 map->callsite_entry_size = 1;
2130 else if (cfg->code_len < 65536)
2131 map->callsite_entry_size = 2;
2133 map->callsite_entry_size = 4;
2135 /* Encode the GC Map */
2143 encode_gc_map (map, buf, &endbuf);
2144 g_assert (endbuf - buf < 256);
2146 encoded_size = endbuf - buf;
2147 alloc_size = sizeof (GCEncodedMap) + ALIGN_TO (encoded_size, map->callsite_entry_size) + (map->callsite_entry_size * map->ncallsites) + bitmaps_size;
2149 emap = mono_domain_alloc0 (cfg->domain, alloc_size);
2150 //emap->ref_slots = map->ref_slots;
2152 /* Encoded fixed fields */
2153 p = &emap->encoded [0];
2154 //emap->encoded_size = encoded_size;
2155 memcpy (p, buf, encoded_size);
2158 /* Callsite table */
2159 p = (guint8*)ALIGN_TO ((guint64)p, map->callsite_entry_size);
2160 if (map->callsite_entry_size == 1) {
2161 guint8 *offsets = p;
2162 for (i = 0; i < ncallsites; ++i)
2163 offsets [i] = callsites [i]->pc_offset;
2164 stats.gc_callsites8_size += ncallsites * sizeof (guint8);
2165 } else if (map->callsite_entry_size == 2) {
2166 guint16 *offsets = (guint16*)p;
2167 for (i = 0; i < ncallsites; ++i)
2168 offsets [i] = callsites [i]->pc_offset;
2169 stats.gc_callsites16_size += ncallsites * sizeof (guint16);
2171 guint32 *offsets = (guint32*)p;
2172 for (i = 0; i < ncallsites; ++i)
2173 offsets [i] = callsites [i]->pc_offset;
2174 stats.gc_callsites32_size += ncallsites * sizeof (guint32);
2176 p += ncallsites * map->callsite_entry_size;
2179 memcpy (p, bitmaps, bitmaps_size);
2181 stats.gc_maps_size += alloc_size;
2182 stats.gc_callsites_size += ncallsites * map->callsite_entry_size;
2183 stats.gc_bitmaps_size += bitmaps_size;
2184 stats.gc_map_struct_size += sizeof (GCEncodedMap) + encoded_size;
2186 cfg->jit_info->gc_info = emap;
2189 stats.all_slots += nslots;
2190 stats.ref_slots += ntypes [SLOT_REF];
2191 stats.noref_slots += ntypes [SLOT_NOREF];
2192 stats.pin_slots += ntypes [SLOT_PIN];
2196 mini_gc_create_gc_map (MonoCompile *cfg)
2198 if (!cfg->compute_gc_maps)
2202 * During marking, all frames except the top frame are at a call site, and we mark the
2203 * top frame conservatively. This means that we only need to compute and record
2204 * GC maps for call sites.
2207 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
2208 /* Without liveness info, the live ranges are not precise enough */
2211 mono_analyze_liveness_gc (cfg);
2213 compute_frame_size (cfg);
2217 process_spill_slots (cfg);
2218 process_other_slots (cfg);
2219 process_param_area_slots (cfg);
2220 process_variables (cfg);
2221 process_finally_clauses (cfg);
2231 memset (&cb, 0, sizeof (cb));
2232 cb.thread_attach_func = thread_attach_func;
2233 cb.thread_detach_func = thread_detach_func;
2234 cb.thread_suspend_func = thread_suspend_func;
2235 /* Comment this out to disable precise stack marking */
2236 cb.thread_mark_func = thread_mark_func;
2237 mono_gc_set_gc_callbacks (&cb);
2239 mono_counters_register ("GC Maps size",
2240 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_maps_size);
2241 mono_counters_register ("GC Call Sites size",
2242 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites_size);
2243 mono_counters_register ("GC Bitmaps size",
2244 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_bitmaps_size);
2245 mono_counters_register ("GC Map struct size",
2246 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_map_struct_size);
2247 mono_counters_register ("GC Call Sites encoded using 8 bits",
2248 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites8_size);
2249 mono_counters_register ("GC Call Sites encoded using 16 bits",
2250 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites16_size);
2251 mono_counters_register ("GC Call Sites encoded using 32 bits",
2252 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.gc_callsites32_size);
2254 mono_counters_register ("GC Map slots (all)",
2255 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.all_slots);
2256 mono_counters_register ("GC Map slots (ref)",
2257 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.ref_slots);
2258 mono_counters_register ("GC Map slots (noref)",
2259 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.noref_slots);
2260 mono_counters_register ("GC Map slots (pin)",
2261 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.pin_slots);
2263 mono_counters_register ("GC TLS Data size",
2264 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.tlsdata_size);
2266 mono_counters_register ("Stack space scanned (all)",
2267 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_stacks);
2268 mono_counters_register ("Stack space scanned (native)",
2269 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_native);
2270 mono_counters_register ("Stack space scanned (other)",
2271 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_other);
2272 mono_counters_register ("Stack space scanned (using GC Maps)",
2273 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned);
2274 mono_counters_register ("Stack space scanned (precise)",
2275 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_precisely);
2276 mono_counters_register ("Stack space scanned (pin)",
2277 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_conservatively);
2278 mono_counters_register ("Stack space scanned (pin registers)",
2279 MONO_COUNTER_GC | MONO_COUNTER_INT, &stats.scanned_registers);
2290 mini_gc_init_gc_map (MonoCompile *cfg)
2295 mini_gc_create_gc_map (MonoCompile *cfg)
2300 mini_gc_set_slot_type_from_fp (MonoCompile *cfg, int slot_offset, GCSlotType type)
2305 mini_gc_set_slot_type_from_cfa (MonoCompile *cfg, int slot_offset, GCSlotType type)
2314 * Set GC specific options in CFG.
2317 mini_gc_init_cfg (MonoCompile *cfg)
2319 if (mono_gc_is_moving ()) {
2320 cfg->disable_ref_noref_stack_slot_share = TRUE;
2321 cfg->gen_write_barriers = TRUE;
2324 mini_gc_init_gc_map (cfg);
2328 * Problems with the current code:
2329 * - the stack walk is slow
2330 * - vtypes/refs used in EH regions are treated conservatively
2331 * - if the code is finished, less pinning will be done, causing problems because
2332 * we promote all surviving objects to old-gen.
2336 * Ideas for creating smaller GC maps:
2337 * - remove empty columns from the bitmaps. This requires adding a mask bit array for
2339 * - merge reg and stack slot bitmaps, so the unused bits at the end of the reg bitmap are
2341 * - if the bitmap width is not a multiple of 8, the remaining bits are wasted.
2342 * - group ref and non-ref stack slots together in mono_allocate_stack_slots ().
2343 * - add an index for the callsite table so that each entry can be encoded as a 1 byte difference
2344 * from an index entry.