hprof_site.c

Go to the documentation of this file.

/*
 * @(#)hprof_site.c 1.43 10/03/23
 * 
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduce the above copyright notice, 
 *  this list of conditions and the following disclaimer in the documentation
 *  and/or other materials provided with the distribution.
 * 
 * Neither the name of Oracle or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

/* Allocation site table. */

/*
 * Every object allocation will have a place where it was allocated,
 *  this is the purpose of the SiteIndex.
 *
 * The allocation site or SiteIndex is unique via a (class,trace) pair.
 *
 * The allocation statistics are accumulated in the SiteInfo for each
 *   site.
 *
 * This file also contains the heap iterate logic, which is closely
 *   associated with the site table, the object table, and the
 *   reference table. Each object has an element in the object table
 *   and as the heap is traversed, and information contained in each
 *   object is saved as a linked list of references.
 *
 */

#include "hprof.h"

typedef struct SiteKey {
    ClassIndex cnum;         /* Unique class number */
    TraceIndex trace_index;  /* Trace number */
} SiteKey;

typedef struct SiteInfo {
    int         changed;               /* Objects at this site changed? */
    unsigned    n_alloced_instances;   /* Total allocated instances */
    unsigned    n_alloced_bytes;       /* Total bytes allocated from here */
    unsigned    n_live_instances;      /* Live instances for this site. */
    unsigned    n_live_bytes;          /* Live byte count for this site. */
} SiteInfo;

typedef struct IterateInfo {
    SiteIndex * site_nums;
    int         count;
    int         changed_only;
} IterateInfo;

/* Private internal functions. */

static SiteKey*
get_pkey(SiteIndex index)
{
    void *key_ptr;
    int   key_len;

    table_get_key(gdata->site_table, index, &key_ptr, &key_len);
    HPROF_ASSERT(key_len==sizeof(SiteKey));
    HPROF_ASSERT(key_ptr!=NULL);
    return (SiteKey*)key_ptr;
}

ClassIndex
site_get_class_index(SiteIndex index) 
{
    SiteKey *pkey;

    pkey = get_pkey(index);
    return pkey->cnum;
}

TraceIndex
site_get_trace_index(SiteIndex index) 
{
    SiteKey *pkey;

    pkey = get_pkey(index);
    return pkey->trace_index;
}

static SiteInfo *
get_info(SiteIndex index)
{
    SiteInfo *info;

    info = (SiteInfo*)table_get_info(gdata->site_table, index);
    return info;
}

static void
list_item(TableIndex i, void *key_ptr, int key_len, void *info_ptr, void *arg)
{
    SiteKey         *pkey;
    jlong            n_alloced_instances;
    jlong            n_alloced_bytes;
    jlong            n_live_instances;
    jlong            n_live_bytes;

    HPROF_ASSERT(key_ptr!=NULL);
    HPROF_ASSERT(key_len==sizeof(SiteKey));
    pkey = (SiteKey*)key_ptr;
    
    if ( info_ptr != NULL ) {
        SiteInfo *info;
    
        info = (SiteInfo *)info_ptr;
        n_alloced_instances    = info->n_alloced_instances;
        n_alloced_bytes        = info->n_alloced_bytes;
        n_live_instances       = info->n_live_instances;
        n_live_bytes           = info->n_live_bytes;
    } else {
        n_alloced_instances    = 0;
        n_alloced_bytes        = 0;
        n_live_instances       = 0;
        n_live_bytes           = 0;
    }
    
    debug_message( "Site 0x%08x: class=0x%08x, trace=0x%08x, "
                          "Ninst=(%d,%d), Nbytes=(%d,%d), "
                          "Nlive=(%d,%d), NliveBytes=(%d,%d)\n",
             i, 
             pkey->cnum, 
             pkey->trace_index,
             jlong_high(n_alloced_instances), jlong_low(n_alloced_instances),
             jlong_high(n_alloced_bytes),     jlong_low(n_alloced_bytes),
             jlong_high(n_live_instances),    jlong_low(n_live_instances),
             jlong_high(n_live_bytes),        jlong_low(n_live_bytes));
}

static void
collect_iterator(TableIndex i, void *key_ptr, int key_len, void *info_ptr, void *arg)
{
    IterateInfo     *iterate;

    HPROF_ASSERT(key_ptr!=NULL);
    HPROF_ASSERT(key_len==sizeof(SiteKey));
    HPROF_ASSERT(arg!=NULL);
    iterate = (IterateInfo *)arg;

    if ( iterate->changed_only ) {
        SiteInfo *info;
        
        info = (SiteInfo *)info_ptr;
        if ( info==NULL || !info->changed ) {
            return;
        }
    }
    iterate->site_nums[iterate->count++] = i;
}

static void
mark_unchanged_iterator(TableIndex i, void *key_ptr, int key_len, void *info_ptr, void *arg)
{
    SiteInfo *info;

    HPROF_ASSERT(key_ptr!=NULL);
    HPROF_ASSERT(key_len==sizeof(SiteKey));
    
    info = (SiteInfo *)info_ptr;
    if ( info != NULL ) {
        info->changed = 0;
    }
}

static int 
qsort_compare_allocated_bytes(const void *p_site1, const void *p_site2)
{
    SiteIndex  site1;
    SiteIndex  site2;
    SiteInfo  *info1;
    SiteInfo  *info2;
    
    HPROF_ASSERT(p_site1!=NULL);
    HPROF_ASSERT(p_site2!=NULL);
    site1 = *(SiteIndex *)p_site1;
    site2 = *(SiteIndex *)p_site2;
    info1 = get_info(site1);
    info2 = get_info(site2);
    return info2->n_alloced_bytes - info1->n_alloced_bytes;
}

static int 
qsort_compare_live_bytes(const void *p_site1, const void *p_site2)
{
    SiteIndex  site1;
    SiteIndex  site2;
    SiteInfo  *info1;
    SiteInfo  *info2;
    
    HPROF_ASSERT(p_site1!=NULL);
    HPROF_ASSERT(p_site2!=NULL);
    site1 = *(SiteIndex *)p_site1;
    site2 = *(SiteIndex *)p_site2;
    info1 = get_info(site1);
    info2 = get_info(site2);
    return info2->n_live_bytes - info1->n_live_bytes;
}

static ClassIndex
find_cnum(jlong class_tag)
{
    ClassIndex  cnum;
    ObjectIndex class_object_index;
    SiteIndex   class_site_index;
    SiteKey    *pkey;

    HPROF_ASSERT(class_tag!=(jlong)0);
    class_object_index = tag_extract(class_tag);
    class_site_index = object_get_site(class_object_index);
    pkey = get_pkey(class_site_index);
    cnum = pkey->cnum;
    return cnum;
}

/* Create tag and object entry for an untagged object (should be rare) */
static jlong
make_new_tag(jlong class_tag, jlong size, TraceIndex trace_index,
                  SerialNumber thread_serial_num,
                  ObjectIndex *pindex, SiteIndex *psite)
{
    ObjectIndex object_index;
    SiteIndex   object_site_index;

    HPROF_ASSERT(class_tag!=(jlong)0);
    object_site_index = site_find_or_create(find_cnum(class_tag), trace_index);
    object_index      = object_new(object_site_index, (jint)size, 
                                   OBJECT_SYSTEM, thread_serial_num);
    if ( pindex != NULL ) {
        *pindex = object_index;
    }
    if ( psite != NULL ) {
        *psite = object_site_index;
    }
    return tag_create(object_index);
}

/* Setup tag on root object, if tagged return object index and site index */
static void
setup_tag_on_root(jlong *tag_ptr, jlong class_tag, jlong size,
                  SerialNumber thread_serial_num,
                  ObjectIndex *pindex, SiteIndex *psite)
{
    HPROF_ASSERT(class_tag!=(jlong)0);
    if ( (*tag_ptr) != (jlong)0 ) {
        if ( pindex != NULL ) {
            *pindex = tag_extract(*tag_ptr);
        }
        if ( psite != NULL ) {
            *psite = object_get_site(tag_extract(*tag_ptr));
        }
    } else {
        /* Create and set the tag. */
        *tag_ptr = make_new_tag(class_tag, size, gdata->system_trace_index,
                  thread_serial_num, pindex, psite);
    }
}

/* External interfaces */

SiteIndex
site_find_or_create(ClassIndex cnum, TraceIndex trace_index)
{
    SiteIndex index;
    static SiteKey  empty_key;
    SiteKey   key;
    
    key = empty_key;
    HPROF_ASSERT(cnum!=0);
    HPROF_ASSERT(trace_index!=0);
    key.cnum        = cnum;
    key.trace_index = trace_index;
    index = table_find_or_create_entry(gdata->site_table, 
                            &key, (int)sizeof(key), NULL, NULL);
    return index;
}

void
site_init(void)
{
    HPROF_ASSERT(gdata->site_table==NULL);
    gdata->site_table = table_initialize("Site",
                            1024, 1024, 511, (int)sizeof(SiteInfo));
}

void
site_list(void)
{
    debug_message( 
        "--------------------- Site Table ------------------------\n");
    table_walk_items(gdata->site_table, &list_item, NULL);
    debug_message(
        "----------------------------------------------------------\n");
}

void
site_cleanup(void)
{
    table_cleanup(gdata->site_table, NULL, NULL);
    gdata->site_table = NULL;
}

void
site_update_stats(SiteIndex index, jint size, jint hits)
{
    SiteInfo *info;
    
    table_lock_enter(gdata->site_table); {
        info = get_info(index);
        
        info->n_live_instances          += hits;
        info->n_live_bytes              += size;
        info->changed                   = 1;
        
        gdata->total_live_bytes         += size;
        gdata->total_live_instances     += hits;
         
        if ( size > 0 ) {
            info->n_alloced_instances   += hits;
            info->n_alloced_bytes       += size;
            gdata->total_alloced_bytes = 
                jlong_add(gdata->total_alloced_bytes, jint_to_jlong(size));
            gdata->total_alloced_instances = 
                jlong_add(gdata->total_alloced_instances, jint_to_jlong(hits));
        }
    } table_lock_exit(gdata->site_table);
}

/* Output allocation sites, up to the given cut-off point, and according
 * to the given flags:
 *
 *      SITE_DUMP_INCREMENTAL only dump what's changed since last dump.
 *      SITE_SORT_BY_ALLOC    sort sites by total allocation rather
 *                                  than live data.
 *      SITE_FORCE_GC         force a GC before the site dump.
 */

void 
site_write(JNIEnv *env, int flags, double cutoff)
{
    HPROF_ASSERT(gdata->site_table!=NULL);
    LOG3("site_write", "flags", flags);
    
    if (flags & SITE_FORCE_GC) {
        runGC();
    }

    HPROF_ASSERT(gdata->total_live_bytes!=0);

    rawMonitorEnter(gdata->data_access_lock); {
        
        IterateInfo     iterate;
        int             site_table_size;
        double          accum_percent;
        void *          comment_str;
        int             i;
        int             cutoff_count;
        int             nbytes;

        accum_percent = 0;
        site_table_size = table_element_count(gdata->site_table);
        
        (void)memset(&iterate, 0, sizeof(iterate));
        nbytes            = site_table_size * (int)sizeof(SiteIndex);
        if ( nbytes > 0 ) {
            iterate.site_nums = HPROF_MALLOC(nbytes);
            (void)memset(iterate.site_nums, 0, nbytes);
        }
        iterate.count   = 0;
        iterate.changed_only = flags & SITE_DUMP_INCREMENTAL;
        table_walk_items(gdata->site_table, &collect_iterator, &iterate);

        site_table_size = iterate.count;
        
        if (flags & SITE_SORT_BY_ALLOC) {
            comment_str = "allocated bytes";
            qsort(iterate.site_nums, site_table_size, sizeof(SiteIndex), 
                    &qsort_compare_allocated_bytes);
        } else {
            comment_str = "live bytes";
            qsort(iterate.site_nums, site_table_size, sizeof(SiteIndex), 
                    &qsort_compare_live_bytes); 
        }

        trace_output_unmarked(env);
        
        cutoff_count = 0;
        for (i = 0; i < site_table_size; i++) {
            SiteInfo   *info;
            SiteIndex   index;
            double      ratio;
            
            index= iterate.site_nums[i];
            HPROF_ASSERT(index!=0);
            info        = get_info(index);
            ratio       = (double)info->n_live_bytes / (double)gdata->total_live_bytes;
            if (ratio < cutoff) {
                break;
            }
            cutoff_count++;
        }
        
        io_write_sites_header(  comment_str,
                                flags,
                                cutoff,
                                gdata->total_live_bytes,
                                gdata->total_live_instances,
                                gdata->total_alloced_bytes,
                                gdata->total_alloced_instances,
                                cutoff_count);
        
        for (i = 0; i < cutoff_count; i++) {
            SiteInfo     *info;
            SiteKey      *pkey;
            SiteIndex     index;
            char         *class_signature;
            double        ratio;
            
            index = iterate.site_nums[i];
            pkey         = get_pkey(index);
            info         = get_info(index);
            
            ratio       = (double)info->n_live_bytes / (double)gdata->total_live_bytes;
            accum_percent += ratio;
            
            class_signature  = string_get(class_get_signature(pkey->cnum));
            
            io_write_sites_elem(i + 1,
                                ratio,
                                accum_percent,
                                class_signature,
                                class_get_serial_number(pkey->cnum),
                                trace_get_serial_number(pkey->trace_index),
                                info->n_live_bytes,
                                info->n_live_instances,
                                info->n_alloced_bytes,
                                info->n_alloced_instances);
        }
        
        io_write_sites_footer();

        table_walk_items(gdata->site_table, &mark_unchanged_iterator, NULL);

        if ( iterate.site_nums != NULL ) {
            HPROF_FREE(iterate.site_nums);
        }

    } rawMonitorExit(gdata->data_access_lock);
}

/* Primitive array data callback for FollowReferences */
static jint JNICALL 
cbPrimArrayData(jlong class_tag, jlong size, jlong* tag_ptr, 
         jint element_count, jvmtiPrimitiveType element_type, 
         const void* elements, void* user_data)
{
    ObjectIndex   object_index;
    RefIndex      ref_index;
    RefIndex      prev_ref_index;

    HPROF_ASSERT(tag_ptr!=NULL);
    HPROF_ASSERT(class_tag!=(jlong)0);
    HPROF_ASSERT((*tag_ptr)!=(jlong)0);
    if ( class_tag == (jlong)0 || (*tag_ptr) == (jlong)0 ) {
        /* We can't do anything with a class_tag==0, just skip it */
        return JVMTI_VISIT_OBJECTS;
    }
   
    /* Assume object has been tagged, get object index */
    object_index = tag_extract((*tag_ptr));

    /* Save string data */
    prev_ref_index = object_get_references(object_index);
    ref_index = reference_prim_array(prev_ref_index,
                  element_type, elements, element_count);
    object_set_references(object_index, ref_index);

    return JVMTI_VISIT_OBJECTS;
}

/* Primitive field data callback for FollowReferences */
static jint JNICALL 
cbPrimFieldData(jvmtiHeapReferenceKind reference_kind, 
         const jvmtiHeapReferenceInfo* reference_info, jlong class_tag, 
         jlong* tag_ptr, jvalue value, jvmtiPrimitiveType value_type, 
         void* user_data)
{
    ObjectIndex   object_index;
    jint          field_index;
    RefIndex      ref_index;
    RefIndex      prev_ref_index;

    HPROF_ASSERT(tag_ptr!=NULL);
    HPROF_ASSERT(class_tag!=(jlong)0);
    HPROF_ASSERT((*tag_ptr)!=(jlong)0);
    if ( class_tag == (jlong)0 || (*tag_ptr) == (jlong)0 ) {
        /* We can't do anything with a class_tag==0, just skip it */
        return JVMTI_VISIT_OBJECTS;
    }

    /* If the field is 0, just skip it, we assume 0 */
    if ( value.j == (jlong)0 ) {
        return JVMTI_VISIT_OBJECTS;
    }

    /* Get field index */
    field_index = reference_info->field.index;
   
    /* We assume the object was tagged */
    object_index = tag_extract((*tag_ptr));
    
    /* Save primitive field data */
    prev_ref_index = object_get_references(object_index);
    ref_index = reference_prim_field(prev_ref_index, reference_kind,
                  value_type, value, field_index);
    object_set_references(object_index, ref_index);

    return JVMTI_VISIT_OBJECTS;
}

static SerialNumber
checkThreadSerialNumber(SerialNumber thread_serial_num)
{
    TlsIndex tls_index;
    
    if ( thread_serial_num == gdata->unknown_thread_serial_num ) {
        return thread_serial_num;
    }
    tls_index = tls_find(thread_serial_num);
    if ( tls_index != 0 && tls_get_in_heap_dump(tls_index) != 0 ) {
        return thread_serial_num;
    }
    return gdata->unknown_thread_serial_num;
}

/* Get the object index and thread serial number for this local object */
static void
localReference(jlong *tag_ptr, jlong class_tag, jlong thread_tag, 
     jlong size, ObjectIndex *pobject_index, SerialNumber *pthread_serial_num)
{
    ObjectIndex  object_index;
    SerialNumber thread_serial_num;

    HPROF_ASSERT(pobject_index!=NULL);
    HPROF_ASSERT(pthread_serial_num!=NULL);
    HPROF_ASSERT(tag_ptr!=NULL);
    HPROF_ASSERT(class_tag!=(jlong)0);
    
    if ( (*tag_ptr) != (jlong)0 ) {
        object_index = tag_extract(*tag_ptr);
        thread_serial_num = object_get_thread_serial_number(object_index);
        thread_serial_num = checkThreadSerialNumber(thread_serial_num);
    } else {
        if ( thread_tag != (jlong)0 ) {
            ObjectIndex thread_object_index;

            thread_object_index = tag_extract(thread_tag);
            thread_serial_num = 
                   object_get_thread_serial_number(thread_object_index);
            thread_serial_num = checkThreadSerialNumber(thread_serial_num);
        } else {
            thread_serial_num = gdata->unknown_thread_serial_num;
        }
        /* Create and set the tag. */
        *tag_ptr = make_new_tag(class_tag, size, gdata->system_trace_index,
                  thread_serial_num, &object_index, NULL);
    }

    HPROF_ASSERT(thread_serial_num!=0);
    HPROF_ASSERT(object_index!=0);
    *pobject_index      = object_index;
    *pthread_serial_num = thread_serial_num;
}

/* Store away plain object reference information */
static jint
objectReference(jvmtiHeapReferenceKind reference_kind, 
                  const jvmtiHeapReferenceInfo* reference_info, 
                  jlong class_tag, jlong size, jlong* tag_ptr, 
                  jlong* referrer_tag_ptr, jint length)
{
    ObjectIndex   object_index;
    jint          reference_index;
    RefIndex      ref_index;
    RefIndex      prev_ref_index;
    ObjectIndex   referrer_object_index;
    jlong         object_tag;

    HPROF_ASSERT(tag_ptr!=NULL);
    HPROF_ASSERT(class_tag!=(jlong)0);
    HPROF_ASSERT(referrer_tag_ptr!=NULL);
    HPROF_ASSERT((*referrer_tag_ptr)!=(jlong)0);
    if ( class_tag == (jlong)0 || (*referrer_tag_ptr) == (jlong)0 ) {
        /* We can't do anything with a class_tag==0, just skip it */
        return JVMTI_VISIT_OBJECTS;
    }
   
    switch ( reference_kind ) {
        case JVMTI_HEAP_REFERENCE_CLASS_LOADER:
        case JVMTI_HEAP_REFERENCE_INTERFACE:
        default:
            /* Currently we don't need these */
            return JVMTI_VISIT_OBJECTS;
        case JVMTI_HEAP_REFERENCE_FIELD:
        case JVMTI_HEAP_REFERENCE_STATIC_FIELD:
            reference_index = reference_info->field.index;
            break;
        case JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT:
            reference_index = reference_info->array.index;
            break;
        case JVMTI_HEAP_REFERENCE_CONSTANT_POOL:
            reference_index = reference_info->constant_pool.index;
            break;
        case JVMTI_HEAP_REFERENCE_SIGNERS:
        case JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN:
            reference_index = 0;
            break;
    }
   
    /* We assume the referrer is tagged */
    referrer_object_index = tag_extract((*referrer_tag_ptr));
   
    /* Now check the referree */
    object_tag = *tag_ptr;
    if ( object_tag != (jlong)0 ) {
        object_index = tag_extract(object_tag);
    } else {
        /* Create and set the tag. */
        object_tag = make_new_tag(class_tag, size, gdata->system_trace_index,
                                  gdata->unknown_thread_serial_num, 
                                  &object_index, NULL);
        *tag_ptr   = object_tag;
    }
    HPROF_ASSERT(object_index!=0);

    /* Save reference information */
    prev_ref_index = object_get_references(referrer_object_index);
    ref_index = reference_obj(prev_ref_index, reference_kind,
                    object_index, reference_index, length);
    object_set_references(referrer_object_index, ref_index);

    return JVMTI_VISIT_OBJECTS;
}

/* FollowReferences heap_reference_callback */
static jint JNICALL 
cbReference(jvmtiHeapReferenceKind reference_kind, 
                  const jvmtiHeapReferenceInfo* reference_info, 
                  jlong class_tag, jlong referrer_class_tag,
                  jlong size, jlong* tag_ptr, 
                  jlong* referrer_tag_ptr, jint length, void* user_data)
{
    ObjectIndex   object_index;

   /* Only calls to Allocate, Deallocate, RawMonitorEnter & RawMonitorExit
    *   are allowed here (see the JVMTI Spec).
    */

    HPROF_ASSERT(tag_ptr!=NULL);
    HPROF_ASSERT(class_tag!=(jlong)0);
    if ( class_tag == (jlong)0 ) {
        /* We can't do anything with a class_tag==0, just skip it */
        return JVMTI_VISIT_OBJECTS;
    }
   
    switch ( reference_kind ) {
        
        case JVMTI_HEAP_REFERENCE_FIELD:
        case JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT:
        case JVMTI_HEAP_REFERENCE_CLASS_LOADER:
        case JVMTI_HEAP_REFERENCE_SIGNERS:
        case JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN:
        case JVMTI_HEAP_REFERENCE_INTERFACE:
        case JVMTI_HEAP_REFERENCE_STATIC_FIELD:
        case JVMTI_HEAP_REFERENCE_CONSTANT_POOL:
            return objectReference(reference_kind, reference_info,
                   class_tag, size, tag_ptr, referrer_tag_ptr, length);
            
        case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: {
                SerialNumber trace_serial_num;
                SerialNumber gref_serial_num;
                TraceIndex   trace_index;
                SiteIndex    object_site_index;
                
                setup_tag_on_root(tag_ptr, class_tag, size,
                                  gdata->unknown_thread_serial_num,
                                  &object_index, &object_site_index);
                if ( object_site_index != 0 ) {
                    SiteKey     *pkey;
                    
                    pkey = get_pkey(object_site_index);
                    trace_index = pkey->trace_index;
                } else {
                    trace_index = gdata->system_trace_index;
                }
                trace_serial_num = trace_get_serial_number(trace_index);
                gref_serial_num  = gdata->gref_serial_number_counter++;
                io_heap_root_jni_global(object_index, gref_serial_num, 
                                        trace_serial_num);
            }
            break;
            
        case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: {
                char        *sig;
                SerialNumber class_serial_num;
                SiteIndex    object_site_index;
    
                setup_tag_on_root(tag_ptr, class_tag, size,
                                  gdata->unknown_thread_serial_num,
                                  &object_index, &object_site_index);
                sig = "Unknown";
                class_serial_num = 0;
                if ( object_site_index != 0 ) {
                    SiteKey *pkey;
                    
                    pkey = get_pkey(object_site_index);
                    sig = string_get(class_get_signature(pkey->cnum));
                    class_serial_num = class_get_serial_number(pkey->cnum);
                }
                io_heap_root_system_class(object_index, sig, class_serial_num);
            }
            break;
            
        case JVMTI_HEAP_REFERENCE_MONITOR:
            setup_tag_on_root(tag_ptr, class_tag, size, 
                              gdata->unknown_thread_serial_num,
                              &object_index, NULL);
            io_heap_root_monitor(object_index);
            break;
            
        case JVMTI_HEAP_REFERENCE_STACK_LOCAL:  {
                SerialNumber thread_serial_num;
                jlong        thread_tag;

                thread_tag = reference_info->stack_local.thread_tag;
                localReference(tag_ptr, class_tag, thread_tag, size,
                             &object_index, &thread_serial_num);
                io_heap_root_java_frame(object_index, thread_serial_num, 
                             reference_info->stack_local.depth);
            }
            break;

        case JVMTI_HEAP_REFERENCE_JNI_LOCAL: {
                SerialNumber thread_serial_num;
                jlong        thread_tag;

                thread_tag = reference_info->jni_local.thread_tag;
                localReference(tag_ptr, class_tag, thread_tag, size,
                             &object_index, &thread_serial_num);
                io_heap_root_jni_local(object_index, thread_serial_num, 
                             reference_info->jni_local.depth);
            }
            break;
            
        case JVMTI_HEAP_REFERENCE_THREAD: {
                SerialNumber thread_serial_num;
                SerialNumber trace_serial_num;
                TraceIndex   trace_index;
                SiteIndex    object_site_index;
                TlsIndex     tls_index;
        
                /* It is assumed that tag_ptr is referring to a 
                 *      java.lang.Thread object here.
                 */
                if ( (*tag_ptr) != (jlong)0 ) {
                    setup_tag_on_root(tag_ptr, class_tag, size, 0,
                                      &object_index, &object_site_index);
                    trace_index       = site_get_trace_index(object_site_index);
                    /* Hopefully the ThreadStart event put this thread's
                     *   correct serial number on it's object.
                     */
                    thread_serial_num = object_get_thread_serial_number(object_index);
                } else {
                    /* Rare situation that a Thread object is not tagged.
                     *   Create special unique thread serial number in this
                     *   case, probably means we never saw a thread start
                     *   or thread end, or even an allocation of the thread
                     *   object.
                     */
                    thread_serial_num = gdata->thread_serial_number_counter++;
                    setup_tag_on_root(tag_ptr, class_tag, size,
                                      thread_serial_num,
                                      &object_index, &object_site_index);
                    trace_index = gdata->system_trace_index;
                }
                /* Get tls_index and set in_heap_dump, if we find it. */
                tls_index = tls_find(thread_serial_num);
                if ( tls_index != 0 ) {
                    tls_set_in_heap_dump(tls_index, 1);
                }
                trace_serial_num = trace_get_serial_number(trace_index);
                /* Issue thread object (must be before thread root) */
                io_heap_root_thread_object(object_index,
                                 thread_serial_num, trace_serial_num);
                /* Issue thread root */
                io_heap_root_thread(object_index, thread_serial_num);
            }
            break;
            
        case JVMTI_HEAP_REFERENCE_OTHER:
            setup_tag_on_root(tag_ptr, class_tag, size,
                              gdata->unknown_thread_serial_num,
                              &object_index, NULL);
            io_heap_root_unknown(object_index);
            break;
       
       default:
            /* Ignore anything else */
            break;

    }
    
    return JVMTI_VISIT_OBJECTS;
}

void
site_heapdump(JNIEnv *env)
{
   
    rawMonitorEnter(gdata->data_access_lock); {

        jvmtiHeapCallbacks heapCallbacks;
        
        /* Remove class dumped status, all classes must be dumped */
        class_all_status_remove(CLASS_DUMPED);

        /* Clear in_heap_dump flag */
        tls_clear_in_heap_dump();
        
        /* Dump the last thread traces and get the lists back we need */
        tls_dump_traces(env);
       
        /* Write header for heap dump */
        io_heap_header(gdata->total_live_instances, gdata->total_live_bytes);

        /* Setup a clean reference table */
        reference_init();
        
        /* Walk over all reachable objects and dump out roots */
        gdata->gref_serial_number_counter = gdata->gref_serial_number_start;

        /* Issue thread object for fake non-existent unknown thread
         *   just in case someone refers to it. Real threads are handled
         *   during iterate over reachable objects.
         */
        io_heap_root_thread_object(0, gdata->unknown_thread_serial_num, 
                        trace_get_serial_number(gdata->system_trace_index));

        /* Iterate over heap and get the real stuff */
        (void)memset(&heapCallbacks, 0, sizeof(heapCallbacks));

        /* Select callbacks */
        heapCallbacks.heap_reference_callback       = &cbReference;
        if ( gdata->primfields == JNI_TRUE ) {
            heapCallbacks.primitive_field_callback  = &cbPrimFieldData;
        }
        if ( gdata->primarrays == JNI_TRUE ) {
            heapCallbacks.array_primitive_value_callback  = &cbPrimArrayData;
        }
        followReferences(&heapCallbacks, (void*)NULL);

        /* Process reference information. */
        object_reference_dump(env);
        object_clear_references();
        reference_cleanup();

        /* Dump the last thread traces and get the lists back we need */
        tls_dump_traces(env);

        /* Write out footer for heap dump */
        io_heap_footer();
        
    } rawMonitorExit(gdata->data_access_lock);
}

---