[sgen] Enqueue objects with their descriptors.

[mono-project.git] / mono / metadata / sgen-old-bridge.c

/*
 * sgen-bridge.c: Simple generational GC.
 *
 * Copyright 2011 Novell, Inc (http://www.novell.com)
 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program
 * for any purpose,  provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *
 *
 * Copyright 2001-2003 Ximian, Inc
 * Copyright 2003-2010 Novell, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "config.h"

#ifdef HAVE_SGEN_GC

#include <stdlib.h>

#include "sgen-gc.h"
#include "sgen-bridge.h"
#include "sgen-hash-table.h"
#include "sgen-qsort.h"
#include "utils/mono-logger-internal.h"
#include "utils/mono-time.h"
#include "utils/mono-compiler.h"


typedef struct {
        int size;
        int capacity;
        char *data;
} DynArray;

/*Specializations*/

typedef struct {
        DynArray array;
} DynIntArray;

typedef struct {
        DynArray array;
} DynPtrArray;

typedef struct {
        DynArray array;
} DynSCCArray;


/*
 * FIXME: Optimizations:
 *
 * Don't allocate a scrs array for just one source.  Most objects have
 * just one source, so use the srcs pointer itself.
 */
typedef struct _HashEntry {
        MonoObject *obj;        /* This is a duplicate - it's already stored in the hash table */

        gboolean is_bridge;
        gboolean is_visited;

        int finishing_time;

        DynPtrArray srcs;

        int scc_index;
} HashEntry;

typedef struct {
        HashEntry entry;
        double weight;
} HashEntryWithAccounting;

typedef struct _SCC {
        int index;
        int api_index;
        int num_bridge_entries;
        DynIntArray xrefs;              /* these are incoming, not outgoing */
} SCC;

static SgenHashTable hash_table = SGEN_HASH_TABLE_INIT (INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE, INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE_ENTRY, sizeof (HashEntry), mono_aligned_addr_hash, NULL);

static int current_time;

static gboolean bridge_accounting_enabled = FALSE;

static SgenBridgeProcessor *bridge_processor;

/* Core functions */
/* public */

/* private */

static void
dyn_array_init (DynArray *da)
{
        da->size = 0;
        da->capacity = 0;
        da->data = NULL;
}

static void
dyn_array_uninit (DynArray *da, int elem_size)
{
        if (da->capacity <= 0)
                return;

        sgen_free_internal_dynamic (da->data, elem_size * da->capacity, INTERNAL_MEM_BRIDGE_DATA);
        da->data = NULL;
}

static void
dyn_array_ensure_capacity (DynArray *da, int capacity, int elem_size)
{
        int old_capacity = da->capacity;
        char *new_data;

        if (capacity <= old_capacity)
                return;

        if (da->capacity == 0)
                da->capacity = 2;
        while (capacity > da->capacity)
                da->capacity *= 2;

        new_data = sgen_alloc_internal_dynamic (elem_size * da->capacity, INTERNAL_MEM_BRIDGE_DATA, TRUE);
        memcpy (new_data, da->data, elem_size * da->size);
        sgen_free_internal_dynamic (da->data, elem_size * old_capacity, INTERNAL_MEM_BRIDGE_DATA);
        da->data = new_data;
}

static void*
dyn_array_add (DynArray *da, int elem_size)
{
        void *p;

        dyn_array_ensure_capacity (da, da->size + 1, elem_size);

        p = da->data + da->size * elem_size;
        ++da->size;
        return p;
}

/* int */
static void
dyn_array_int_init (DynIntArray *da)
{
        dyn_array_init (&da->array);
}

static void
dyn_array_int_uninit (DynIntArray *da)
{
        dyn_array_uninit (&da->array, sizeof (int));
}

static int
dyn_array_int_size (DynIntArray *da)
{
        return da->array.size;
}

static void
dyn_array_int_set_size (DynIntArray *da, int size)
{
        da->array.size = size;
}

static void
dyn_array_int_add (DynIntArray *da, int x)
{
        int *p = dyn_array_add (&da->array, sizeof (int));
        *p = x;
}

static int
dyn_array_int_get (DynIntArray *da, int x)
{
        return ((int*)da->array.data)[x];
}

static void
dyn_array_int_set (DynIntArray *da, int idx, int val)
{
        ((int*)da->array.data)[idx] = val;
}

static void
dyn_array_int_ensure_capacity (DynIntArray *da, int capacity)
{
        dyn_array_ensure_capacity (&da->array, capacity, sizeof (int));
}

static void
dyn_array_int_set_all (DynIntArray *dst, DynIntArray *src)
{
        dyn_array_int_ensure_capacity (dst, src->array.size);
        memcpy (dst->array.data, src->array.data, src->array.size * sizeof (int));
        dst->array.size = src->array.size;
}

/* ptr */

static void
dyn_array_ptr_init (DynPtrArray *da)
{
        dyn_array_init (&da->array);
}

static void
dyn_array_ptr_uninit (DynPtrArray *da)
{
        dyn_array_uninit (&da->array, sizeof (void*));
}

static int
dyn_array_ptr_size (DynPtrArray *da)
{
        return da->array.size;
}

static void
dyn_array_ptr_set_size (DynPtrArray *da, int size)
{
        da->array.size = size;
}

static void*
dyn_array_ptr_get (DynPtrArray *da, int x)
{
        return ((void**)da->array.data)[x];
}

static void
dyn_array_ptr_add (DynPtrArray *da, void *ptr)
{
        void **p = dyn_array_add (&da->array, sizeof (void*));
        *p = ptr;
}

#define dyn_array_ptr_push dyn_array_ptr_add

static void*
dyn_array_ptr_pop (DynPtrArray *da)
{
        void *p;
        int size = da->array.size;
        g_assert (size > 0);
        p = dyn_array_ptr_get (da, size - 1);
        --da->array.size;
        return p;
}

/*SCC */

static void
dyn_array_scc_init (DynSCCArray *da)
{
        dyn_array_init (&da->array);
}

static void
dyn_array_scc_uninit (DynSCCArray *da)
{
        dyn_array_uninit (&da->array, sizeof (SCC));
}

static int
dyn_array_scc_size (DynSCCArray *da)
{
        return da->array.size;
}

static SCC*
dyn_array_scc_add (DynSCCArray *da)
{
        return dyn_array_add (&da->array, sizeof (SCC));
}

static SCC*
dyn_array_scc_get_ptr (DynSCCArray *da, int x)
{
        return &((SCC*)da->array.data)[x];
}

/* Merge code*/

static DynIntArray merge_array;

static gboolean
dyn_array_int_contains (DynIntArray *da, int x)
{
        int i;
        for (i = 0; i < dyn_array_int_size (da); ++i)
                if (dyn_array_int_get (da, i) == x)
                        return TRUE;
        return FALSE;
}


static void
dyn_array_int_merge (DynIntArray *dst, DynIntArray *src)
{
        int i, j;

        dyn_array_int_ensure_capacity (&merge_array, dyn_array_int_size (dst) + dyn_array_int_size (src));
        dyn_array_int_set_size (&merge_array, 0);

        for (i = j = 0; i < dyn_array_int_size (dst) || j < dyn_array_int_size (src); ) {
                if (i < dyn_array_int_size (dst) && j < dyn_array_int_size (src)) {
                        int a = dyn_array_int_get (dst, i); 
                        int b = dyn_array_int_get (src, j); 
                        if (a < b) {
                                dyn_array_int_add (&merge_array, a);
                                ++i;
                        } else if (a == b) {
                                dyn_array_int_add (&merge_array, a);
                                ++i;
                                ++j;    
                        } else {
                                dyn_array_int_add (&merge_array, b);
                                ++j;
                        }
                } else if (i < dyn_array_int_size (dst)) {
                        dyn_array_int_add (&merge_array, dyn_array_int_get (dst, i));
                        ++i;
                } else {
                        dyn_array_int_add (&merge_array, dyn_array_int_get (src, j));
                        ++j;
                }
        }

        if (dyn_array_int_size (&merge_array) > dyn_array_int_size (dst)) {
                dyn_array_int_set_all (dst, &merge_array);
        }
}

static void
dyn_array_int_merge_one (DynIntArray *array, int value)
{
        int i;
        int tmp;
        int size = dyn_array_int_size (array);

        for (i = 0; i < size; ++i) {
                if (dyn_array_int_get (array, i) == value)
                        return;
                else if (dyn_array_int_get (array, i) > value)
                        break;
        }

        dyn_array_int_ensure_capacity (array, size + 1);

        if (i < size) {
                tmp = dyn_array_int_get (array, i);
                for (; i < size; ++i) {
                        dyn_array_int_set (array, i, value);
                        value = tmp;
                        tmp = dyn_array_int_get (array, i + 1);
                }
                dyn_array_int_set (array, size, value);
        } else {
                dyn_array_int_set (array, size, value);
        }

        dyn_array_int_set_size (array, size + 1);
}


static void
enable_accounting (void)
{
        SgenHashTable table = SGEN_HASH_TABLE_INIT (INTERNAL_MEM_BRIDGE_HASH_TABLE, INTERNAL_MEM_BRIDGE_HASH_TABLE_ENTRY, sizeof (HashEntryWithAccounting), mono_aligned_addr_hash, NULL);
        bridge_accounting_enabled = TRUE;
        hash_table = table;
}

static MonoGCBridgeObjectKind
class_kind (MonoClass *class)
{
        return bridge_callbacks.bridge_class_kind (class);
}

static HashEntry*
get_hash_entry (MonoObject *obj, gboolean *existing)
{
        HashEntry *entry = sgen_hash_table_lookup (&hash_table, obj);
        HashEntry new_entry;

        if (entry) {
                if (existing)
                        *existing = TRUE;
                return entry;
        }
        if (existing)
                *existing = FALSE;

        memset (&new_entry, 0, sizeof (HashEntry));

        new_entry.obj = obj;
        dyn_array_ptr_init (&new_entry.srcs);
        new_entry.finishing_time = -1;
        new_entry.scc_index = -1;

        sgen_hash_table_replace (&hash_table, obj, &new_entry, NULL);

        return sgen_hash_table_lookup (&hash_table, obj);
}

static void
add_source (HashEntry *entry, HashEntry *src)
{
        dyn_array_ptr_add (&entry->srcs, src);
}

static void
free_data (void)
{
        MonoObject *obj;
        HashEntry *entry;
        int total_srcs = 0;
        int max_srcs = 0;

        SGEN_HASH_TABLE_FOREACH (&hash_table, obj, entry) {
                int entry_size = dyn_array_ptr_size (&entry->srcs);
                total_srcs += entry_size;
                if (entry_size > max_srcs)
                        max_srcs = entry_size;
                dyn_array_ptr_uninit (&entry->srcs);
        } SGEN_HASH_TABLE_FOREACH_END;

        sgen_hash_table_clean (&hash_table);

        dyn_array_int_uninit (&merge_array);
        //g_print ("total srcs %d - max %d\n", total_srcs, max_srcs);
}

static HashEntry*
register_bridge_object (MonoObject *obj)
{
        HashEntry *entry = get_hash_entry (obj, NULL);
        entry->is_bridge = TRUE;
        return entry;
}

static void
register_finishing_time (HashEntry *entry, int t)
{
        g_assert (entry->finishing_time < 0);
        entry->finishing_time = t;
}

static gboolean
object_is_live (MonoObject **objp)
{
        MonoObject *obj = *objp;
        MonoObject *fwd = SGEN_OBJECT_IS_FORWARDED (obj);
        if (fwd) {
                *objp = fwd;
                return sgen_hash_table_lookup (&hash_table, fwd) == NULL;
        }
        if (!sgen_object_is_live (obj))
                return FALSE;
        return sgen_hash_table_lookup (&hash_table, obj) == NULL;
}

static DynPtrArray registered_bridges;
static DynPtrArray dfs_stack;

static int dfs1_passes, dfs2_passes;


#undef HANDLE_PTR
#define HANDLE_PTR(ptr,obj)     do {                                    \
                MonoObject *dst = (MonoObject*)*(ptr);                  \
                if (dst && !object_is_live (&dst)) {                    \
                        dyn_array_ptr_push (&dfs_stack, obj_entry);     \
                        dyn_array_ptr_push (&dfs_stack, get_hash_entry (dst, NULL)); \
                }                                                       \
        } while (0)

static void
dfs1 (HashEntry *obj_entry)
{
        HashEntry *src;
        g_assert (dyn_array_ptr_size (&dfs_stack) == 0);

        dyn_array_ptr_push (&dfs_stack, NULL);
        dyn_array_ptr_push (&dfs_stack, obj_entry);

        do {
                MonoObject *obj;
                char *start;
                ++dfs1_passes;

                obj_entry = dyn_array_ptr_pop (&dfs_stack);
                if (obj_entry) {
                        mword desc;
                        src = dyn_array_ptr_pop (&dfs_stack);

                        obj = obj_entry->obj;
                        start = (char*)obj;
                        desc = sgen_obj_get_descriptor (start);

                        if (src) {
                                //g_print ("link %s -> %s\n", sgen_safe_name (src->obj), sgen_safe_name (obj));
                                add_source (obj_entry, src);
                        } else {
                                //g_print ("starting with %s\n", sgen_safe_name (obj));
                        }

                        if (obj_entry->is_visited)
                                continue;

                        obj_entry->is_visited = TRUE;

                        dyn_array_ptr_push (&dfs_stack, obj_entry);
                        /* NULL marks that the next entry is to be finished */
                        dyn_array_ptr_push (&dfs_stack, NULL);

#include "sgen-scan-object.h"
                } else {
                        obj_entry = dyn_array_ptr_pop (&dfs_stack);

                        //g_print ("finish %s\n", sgen_safe_name (obj_entry->obj));
                        register_finishing_time (obj_entry, current_time++);
                }
        } while (dyn_array_ptr_size (&dfs_stack) > 0);
}

static void
scc_add_xref (SCC *src, SCC *dst)
{
        g_assert (src != dst);
        g_assert (src->index != dst->index);

        if (dyn_array_int_contains (&dst->xrefs, src->index))
                return;
        if (src->num_bridge_entries) {
                dyn_array_int_merge_one (&dst->xrefs, src->index);
        } else {
                int i;
                dyn_array_int_merge (&dst->xrefs, &src->xrefs);
                for (i = 0; i < dyn_array_int_size (&dst->xrefs); ++i)
                        g_assert (dyn_array_int_get (&dst->xrefs, i) != dst->index);
        }
}

static void
scc_add_entry (SCC *scc, HashEntry *entry)
{
        g_assert (entry->scc_index < 0);
        entry->scc_index = scc->index;
        if (entry->is_bridge)
                ++scc->num_bridge_entries;
}

static DynSCCArray sccs;
static SCC *current_scc;

static void
dfs2 (HashEntry *entry)
{
        int i;

        g_assert (dyn_array_ptr_size (&dfs_stack) == 0);

        dyn_array_ptr_push (&dfs_stack, entry);

        do {
                entry = dyn_array_ptr_pop (&dfs_stack);
                ++dfs2_passes;

                if (entry->scc_index >= 0) {
                        if (entry->scc_index != current_scc->index)
                                scc_add_xref (dyn_array_scc_get_ptr (&sccs, entry->scc_index), current_scc);
                        continue;
                }

                scc_add_entry (current_scc, entry);

                for (i = 0; i < dyn_array_ptr_size (&entry->srcs); ++i)
                        dyn_array_ptr_push (&dfs_stack, dyn_array_ptr_get (&entry->srcs, i));
        } while (dyn_array_ptr_size (&dfs_stack) > 0);
}

static int
compare_hash_entries (const HashEntry *e1, const HashEntry *e2)
{
        return e2->finishing_time - e1->finishing_time;
}

DEF_QSORT_INLINE(hash_entries, HashEntry*, compare_hash_entries)

static unsigned long step_1, step_2, step_3, step_4, step_5, step_6;
static int fist_pass_links, second_pass_links, sccs_links;
static int max_sccs_links = 0;

static void
register_finalized_object (MonoObject *obj)
{
        g_assert (sgen_need_bridge_processing ());
        dyn_array_ptr_push (&registered_bridges, obj);
}

static void
reset_data (void)
{
        dyn_array_ptr_set_size (&registered_bridges, 0);
}

static void
processing_stw_step (void)
{
        int i;
        int bridge_count;
        SGEN_TV_DECLARE (atv);
        SGEN_TV_DECLARE (btv);

        if (!dyn_array_ptr_size (&registered_bridges))
                return;

        SGEN_TV_GETTIME (btv);

        /* first DFS pass */

        dyn_array_ptr_init (&dfs_stack);
        dyn_array_int_init (&merge_array);

        current_time = 0;
        /*
        First we insert all bridges into the hash table and then we do dfs1.

        It must be done in 2 steps since the bridge arrays doesn't come in reverse topological order,
        which means that we can have entry N pointing to entry N + 1.

        If we dfs1 entry N before N + 1 is registered we'll not consider N + 1 for this bridge
        pass and not create the required xref between the two.
        */
        bridge_count = dyn_array_ptr_size (&registered_bridges);
        for (i = 0; i < bridge_count ; ++i)
                register_bridge_object (dyn_array_ptr_get (&registered_bridges, i));

        for (i = 0; i < bridge_count; ++i)
                dfs1 (get_hash_entry (dyn_array_ptr_get (&registered_bridges, i), NULL));

        SGEN_TV_GETTIME (atv);
        step_2 = SGEN_TV_ELAPSED (btv, atv);
}

static int num_registered_bridges, hash_table_size;

static void
processing_build_callback_data (int generation)
{
        int i, j;
        int num_sccs, num_xrefs;
        int max_entries, max_xrefs;
        int sccs_size;
        MonoObject *obj;
        HashEntry *entry;
        HashEntry **all_entries;
        MonoGCBridgeSCC **api_sccs;
        MonoGCBridgeXRef *api_xrefs;
        SGEN_TV_DECLARE (atv);
        SGEN_TV_DECLARE (btv);

        g_assert (bridge_processor->num_sccs == 0 && bridge_processor->num_xrefs == 0);
        g_assert (!bridge_processor->api_sccs && !bridge_processor->api_xrefs);

        if (!dyn_array_ptr_size (&registered_bridges))
                return;

        g_assert (bridge_processing_in_progress);

        SGEN_TV_GETTIME (atv);

        /* alloc and fill array of all entries */

        all_entries = sgen_alloc_internal_dynamic (sizeof (HashEntry*) * hash_table.num_entries, INTERNAL_MEM_BRIDGE_DATA, TRUE);

        j = 0;
        SGEN_HASH_TABLE_FOREACH (&hash_table, obj, entry) {
                g_assert (entry->finishing_time >= 0);
                all_entries [j++] = entry;
                fist_pass_links += dyn_array_ptr_size (&entry->srcs);
        } SGEN_HASH_TABLE_FOREACH_END;
        g_assert (j == hash_table.num_entries);
        hash_table_size = hash_table.num_entries;

        /* sort array according to decreasing finishing time */
        qsort_hash_entries (all_entries, hash_table.num_entries);

        SGEN_TV_GETTIME (btv);
        step_3 = SGEN_TV_ELAPSED (atv, btv);

        /* second DFS pass */

        dyn_array_scc_init (&sccs);
        for (i = 0; i < hash_table.num_entries; ++i) {
                HashEntry *entry = all_entries [i];
                if (entry->scc_index < 0) {
                        int index = dyn_array_scc_size (&sccs);
                        current_scc = dyn_array_scc_add (&sccs);
                        current_scc->index = index;
                        current_scc->num_bridge_entries = 0;
                        current_scc->api_index = -1;
                        dyn_array_int_init (&current_scc->xrefs);

                        dfs2 (entry);
                }
        }

        /*
         * Compute the weight of each object. The weight of an object is its size plus the size of all
         * objects it points do. When the an object is pointed by multiple objects we distribute it's weight
         * equally among them. This distribution gives a rough estimate of the real impact of making the object
         * go away.
         *
         * The reasoning for this model is that complex graphs with single roots will have a bridge with very high
         * value in comparison to others.
         *
         * The all_entries array has all objects topologically sorted. To correctly propagate the weights it must be
         * done in reverse topological order - so we calculate the weight of the pointed-to objects before processing
         * pointer-from objects.
         *
         * We log those objects in the opposite order for no particular reason. The other constrain is that it should use the same
         * direction as the other logging loop that records live/dead information.
         */
        if (bridge_accounting_enabled) {
                for (i = hash_table.num_entries - 1; i >= 0; --i) {
                        double w;
                        HashEntryWithAccounting *entry = (HashEntryWithAccounting*)all_entries [i];

                        entry->weight += (double)sgen_safe_object_get_size (entry->entry.obj);
                        w = entry->weight / dyn_array_ptr_size (&entry->entry.srcs);
                        for (j = 0; j < dyn_array_ptr_size (&entry->entry.srcs); ++j) {
                                HashEntryWithAccounting *other = (HashEntryWithAccounting *)dyn_array_ptr_get (&entry->entry.srcs, j);
                                other->weight += w;
                        }
                }
                for (i = 0; i < hash_table.num_entries; ++i) {
                        HashEntryWithAccounting *entry = (HashEntryWithAccounting*)all_entries [i];
                        if (entry->entry.is_bridge) {
                                MonoClass *klass = ((MonoVTable*)SGEN_LOAD_VTABLE (entry->entry.obj))->klass;
                                mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "OBJECT %s::%s (%p) weight %f", klass->name_space, klass->name, entry->entry.obj, entry->weight);
                        }
                }
        }

        sccs_size = dyn_array_scc_size (&sccs);

        for (i = 0; i < hash_table.num_entries; ++i) {
                HashEntry *entry = all_entries [i];
                second_pass_links += dyn_array_ptr_size (&entry->srcs);
        }

        SGEN_TV_GETTIME (atv);
        step_4 = SGEN_TV_ELAPSED (btv, atv);

        //g_print ("%d sccs\n", sccs.size);

        dyn_array_ptr_uninit (&dfs_stack);

        /* init data for callback */

        num_sccs = 0;
        for (i = 0; i < dyn_array_scc_size (&sccs); ++i) {
                SCC *scc = dyn_array_scc_get_ptr (&sccs, i);
                g_assert (scc->index == i);
                if (scc->num_bridge_entries)
                        ++num_sccs;
                sccs_links += dyn_array_int_size (&scc->xrefs);
                max_sccs_links = MAX (max_sccs_links, dyn_array_int_size (&scc->xrefs));
        }

        api_sccs = sgen_alloc_internal_dynamic (sizeof (MonoGCBridgeSCC*) * num_sccs, INTERNAL_MEM_BRIDGE_DATA, TRUE);
        num_xrefs = 0;
        j = 0;
        for (i = 0; i < dyn_array_scc_size (&sccs); ++i) {
                SCC *scc = dyn_array_scc_get_ptr (&sccs, i);
                if (!scc->num_bridge_entries)
                        continue;

                api_sccs [j] = sgen_alloc_internal_dynamic (sizeof (MonoGCBridgeSCC) + sizeof (MonoObject*) * scc->num_bridge_entries, INTERNAL_MEM_BRIDGE_DATA, TRUE);
                api_sccs [j]->is_alive = FALSE;
                api_sccs [j]->num_objs = scc->num_bridge_entries;
                scc->num_bridge_entries = 0;
                scc->api_index = j++;

                num_xrefs += dyn_array_int_size (&scc->xrefs);
        }

        SGEN_HASH_TABLE_FOREACH (&hash_table, obj, entry) {
                if (entry->is_bridge) {
                        SCC *scc = dyn_array_scc_get_ptr (&sccs, entry->scc_index);
                        api_sccs [scc->api_index]->objs [scc->num_bridge_entries++] = entry->obj;
                }
        } SGEN_HASH_TABLE_FOREACH_END;

        api_xrefs = sgen_alloc_internal_dynamic (sizeof (MonoGCBridgeXRef) * num_xrefs, INTERNAL_MEM_BRIDGE_DATA, TRUE);
        j = 0;
        for (i = 0; i < dyn_array_scc_size (&sccs); ++i) {
                int k;
                SCC *scc = dyn_array_scc_get_ptr (&sccs, i);
                if (!scc->num_bridge_entries)
                        continue;
                for (k = 0; k < dyn_array_int_size (&scc->xrefs); ++k) {
                        SCC *src_scc = dyn_array_scc_get_ptr (&sccs, dyn_array_int_get (&scc->xrefs, k));
                        if (!src_scc->num_bridge_entries)
                                continue;
                        api_xrefs [j].src_scc_index = src_scc->api_index;
                        api_xrefs [j].dst_scc_index = scc->api_index;
                        ++j;
                }
        }

        SGEN_TV_GETTIME (btv);
        step_5 = SGEN_TV_ELAPSED (atv, btv);

        /* free data */

        j = 0;
        max_entries = max_xrefs = 0;
        for (i = 0; i < dyn_array_scc_size (&sccs); ++i) {
                SCC *scc = dyn_array_scc_get_ptr (&sccs, i);
                if (scc->num_bridge_entries)
                        ++j;
                if (scc->num_bridge_entries > max_entries)
                        max_entries = scc->num_bridge_entries;
                if (dyn_array_int_size (&scc->xrefs) > max_xrefs)
                        max_xrefs = dyn_array_int_size (&scc->xrefs);
                dyn_array_int_uninit (&scc->xrefs);

        }
        dyn_array_scc_uninit (&sccs);

        sgen_free_internal_dynamic (all_entries, sizeof (HashEntry*) * hash_table.num_entries, INTERNAL_MEM_BRIDGE_DATA);

        free_data ();
        /* Empty the registered bridges array */
        num_registered_bridges = dyn_array_ptr_size (&registered_bridges);
        dyn_array_ptr_set_size (&registered_bridges, 0);

        SGEN_TV_GETTIME (atv);
        step_6 = SGEN_TV_ELAPSED (btv, atv);

        //g_print ("%d sccs containing bridges - %d max bridge objects - %d max xrefs\n", j, max_entries, max_xrefs);

        bridge_processor->num_sccs = num_sccs;
        bridge_processor->api_sccs = api_sccs;
        bridge_processor->num_xrefs = num_xrefs;
        bridge_processor->api_xrefs = api_xrefs;
}

static void
processing_after_callback (int generation)
{
        int i, j;
        int num_sccs = bridge_processor->num_sccs;
        MonoGCBridgeSCC **api_sccs = bridge_processor->api_sccs;

        if (bridge_accounting_enabled) {
                for (i = 0; i < num_sccs; ++i) {
                        for (j = 0; j < api_sccs [i]->num_objs; ++j)
                                mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC,
                                        "OBJECT %s (%p) SCC [%d] %s",
                                                sgen_safe_name (api_sccs [i]->objs [j]), api_sccs [i]->objs [j],
                                                i,
                                                api_sccs [i]->is_alive  ? "ALIVE" : "DEAD");
                }
        }

        mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_OLD_BRIDGE num-objects %d num_hash_entries %d sccs size %d init %.2fms df1 %.2fms sort %.2fms dfs2 %.2fms setup-cb %.2fms free-data %.2fms links %d/%d/%d/%d dfs passes %d/%d",
                num_registered_bridges, hash_table_size, dyn_array_scc_size (&sccs),
                step_1 / 10000.0f,
                step_2 / 10000.0f,
                step_3 / 10000.0f,
                step_4 / 10000.0f,
                step_5 / 10000.0f,
                step_6 / 10000.0f,
                fist_pass_links, second_pass_links, sccs_links, max_sccs_links,
                dfs1_passes, dfs2_passes);

        step_1 = 0; /* We must cleanup since this value is used as an accumulator. */
        fist_pass_links = second_pass_links = sccs_links = max_sccs_links = 0;
        dfs1_passes = dfs2_passes = 0;
}

static void
describe_pointer (MonoObject *obj)
{
        HashEntry *entry;
        int i;

        for (i = 0; i < dyn_array_ptr_size (&registered_bridges); ++i) {
                if (obj == dyn_array_ptr_get (&registered_bridges, i)) {
                        printf ("Pointer is a registered bridge object.\n");
                        break;
                }
        }

        entry = sgen_hash_table_lookup (&hash_table, obj);
        if (!entry)
                return;

        printf ("Bridge hash table entry %p:\n", entry);
        printf ("  is bridge: %d\n", (int)entry->is_bridge);
        printf ("  is visited: %d\n", (int)entry->is_visited);
}

void
sgen_old_bridge_init (SgenBridgeProcessor *collector)
{
        collector->reset_data = reset_data;
        collector->processing_stw_step = processing_stw_step;
        collector->processing_build_callback_data = processing_build_callback_data;
        collector->processing_after_callback = processing_after_callback;
        collector->class_kind = class_kind;
        collector->register_finalized_object = register_finalized_object;
        collector->describe_pointer = describe_pointer;
        collector->enable_accounting = enable_accounting;

        bridge_processor = collector;
}

#endif