heaptracker.c

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/*
 * @(#)heapTracker.c	1.21 06/02/16
 * 
 * Copyright (c) 2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc. 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 MIDROSYSTEMS, 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.
 */

#include "stdlib.h"

#include "heapTracker.h"
#include "java_crw_demo.h"

#include "jni.h"
#include "jvmti.h"

#include "agent_util.h"

/* ------------------------------------------------------------------- 
 * Some constant names that tie to Java class/method names.
 *    We assume the Java class whose static methods we will be calling
 *    looks like:
 *
 * public class HeapTracker {
 *     private static int engaged; 
 *     private static native void _newobj(Object thr, Object o);
 *     public static void newobj(Object o)
 *     {
 *              if ( engaged != 0 ) {
 *               _newobj(Thread.currentThread(), o);
 *           }
 *     }
 *     private static native void _newarr(Object thr, Object a);
 *     public static void newarr(Object a)
 *     {
 *            if ( engaged != 0 ) {
 *               _newarr(Thread.currentThread(), a);
 *           }
 *     }
 * }
 *
 *    The engaged field allows us to inject all classes (even system classes)
 *    and delay the actual calls to the native code until the VM has reached
 *    a safe time to call native methods (Past the JVMTI VM_START event).
 * 
 */

#define HEAP_TRACKER_class           HeapTracker /* Name of class we are using */
#define HEAP_TRACKER_newobj        newobj   /* Name of java init method */
#define HEAP_TRACKER_newarr        newarr   /* Name of java newarray method */
#define HEAP_TRACKER_native_newobj _newobj  /* Name of java newobj native */
#define HEAP_TRACKER_native_newarr _newarr  /* Name of java newarray native */
#define HEAP_TRACKER_engaged       engaged  /* Name of static field switch */

/* C macros to create strings from tokens */
#define _STRING(s) #s
#define STRING(s) _STRING(s)

/* ------------------------------------------------------------------- */

/* Flavors of traces (to separate out stack traces) */

typedef enum { 
    TRACE_FIRST                        = 0,
    TRACE_USER                        = 0, 
    TRACE_BEFORE_VM_START        = 1, 
    TRACE_BEFORE_VM_INIT        = 2, 
    TRACE_VM_OBJECT                = 3,
    TRACE_MYSTERY                = 4,
    TRACE_LAST                        = 4 
} TraceFlavor;

static char * flavorDesc[] = {
    "",
    "before VM_START",
    "before VM_INIT",
    "VM_OBJECT",
    "unknown"
};

/* Trace (Stack Trace) */

#define MAX_FRAMES 6
typedef struct Trace {
    /* Number of frames (includes HEAP_TRACKER methods) */
    jint           nframes;
    /* Frames from GetStackTrace() (2 extra for HEAP_TRACKER methods) */
    jvmtiFrameInfo frames[MAX_FRAMES+2];
    /* Used to make some traces unique */
    TraceFlavor    flavor;
} Trace;

/* Trace information (more than one object will have this as a tag) */

typedef struct TraceInfo {
    /* Trace where this object was allocated from */
    Trace             trace;
    /* 64 bit hash code that attempts to identify this specific trace */
    jlong             hashCode;
    /* Total space taken up by objects allocated from this trace */
    jlong             totalSpace;
    /* Total count of objects ever allocated from this trace */
    int               totalCount;
    /* Total live objects that were allocated from this trace */
    int               useCount;
    /* The next TraceInfo in the hash bucket chain */
    struct TraceInfo *next;
} TraceInfo;

/* Global agent data structure */

typedef struct {
    /* JVMTI Environment */
    jvmtiEnv      *jvmti;
    /* State of the VM flags */
    jboolean       vmStarted;
    jboolean       vmInitialized;
    jboolean       vmDead;
    /* Options */
    int            maxDump;
    /* Data access Lock */
    jrawMonitorID  lock;
    /* Counter on classes where BCI has been applied */
    jint           ccount;
    /* Hash table to lookup TraceInfo's via Trace's */
    #define HASH_INDEX_BIT_WIDTH 12 /* 4096 */
    #define HASH_BUCKET_COUNT (1<<HASH_INDEX_BIT_WIDTH)
    #define HASH_INDEX_MASK (HASH_BUCKET_COUNT-1)
    TraceInfo     *hashBuckets[HASH_BUCKET_COUNT];
    /* Count of TraceInfo's allocated */
    int            traceInfoCount;
    /* Pre-defined traces for the system and mystery situations */
    TraceInfo     *emptyTrace[TRACE_LAST+1];
} GlobalAgentData;

static GlobalAgentData *gdata;

/* Enter a critical section by doing a JVMTI Raw Monitor Enter */
static void
enterCriticalSection(jvmtiEnv *jvmti)
{
    jvmtiError error;
    
    error = (*jvmti)->RawMonitorEnter(jvmti, gdata->lock);
    check_jvmti_error(jvmti, error, "Cannot enter with raw monitor");
}

/* Exit a critical section by doing a JVMTI Raw Monitor Exit */
static void
exitCriticalSection(jvmtiEnv *jvmti)
{
    jvmtiError error;
    
    error = (*jvmti)->RawMonitorExit(jvmti, gdata->lock);
    check_jvmti_error(jvmti, error, "Cannot exit with raw monitor");
}

/* Update stats on a TraceInfo */
static TraceInfo *
updateStats(TraceInfo *tinfo)
{
    tinfo->totalCount++;
    tinfo->useCount++;
    return tinfo;
}

/* Get TraceInfo for empty stack */
static TraceInfo *
emptyTrace(TraceFlavor flavor)
{
    return updateStats(gdata->emptyTrace[flavor]);
}

/* Allocate new TraceInfo */
static TraceInfo *
newTraceInfo(Trace *trace, jlong hashCode, TraceFlavor flavor)
{
    TraceInfo *tinfo;
    
    tinfo = (TraceInfo*)calloc(1, sizeof(TraceInfo));
    if ( tinfo == NULL ) {
        fatal_error("ERROR: Ran out of malloc() space\n");
    } else {
        int hashIndex;

        tinfo->trace = *trace;
        tinfo->trace.flavor = flavor;
        tinfo->hashCode = hashCode;
        gdata->traceInfoCount++;
        hashIndex = (int)(hashCode & HASH_INDEX_MASK);
        tinfo->next = gdata->hashBuckets[hashIndex];
        gdata->hashBuckets[hashIndex] = tinfo;
    }
    return tinfo;
}

/* Create hash code for a Trace */
static jlong
hashTrace(Trace *trace)
{
    jlong hashCode;
    int   i;
    
    hashCode = 0;
    for ( i = 0 ; i < trace->nframes ; i++ ) {
        hashCode = (hashCode << 3) + 
                (jlong)(ptrdiff_t)(void*)(trace->frames[i].method);
        hashCode = (hashCode << 2) + 
                (jlong)(trace->frames[i].location);
    }
    hashCode = (hashCode << 3) + trace->nframes;
    hashCode += trace->flavor;
    return hashCode;
}

/* Lookup or create a new TraceInfo */
static TraceInfo *
lookupOrEnter(jvmtiEnv *jvmti, Trace *trace, TraceFlavor flavor)
{
    TraceInfo *tinfo;
    jlong      hashCode;

    /* Calculate hash code (outside critical section to lessen contention) */
    hashCode = hashTrace(trace);

    /* Do a lookup in the hash table */
    enterCriticalSection(jvmti); {
        TraceInfo *prev;
        int        hashIndex;

        /* Start with first item in hash buck chain */
        prev = NULL;
        hashIndex = (int)(hashCode & HASH_INDEX_MASK);
        tinfo = gdata->hashBuckets[hashIndex];
        while ( tinfo != NULL ) {
            if ( tinfo->hashCode == hashCode &&
                 memcmp(trace, &(tinfo->trace), sizeof(Trace))==0 ) {
                 /* We found one that matches, move to head of bucket chain */
                 if ( prev != NULL ) {
                     /* Remove from list and add to head of list */
                     prev->next = tinfo->next;
                     tinfo->next = gdata->hashBuckets[hashIndex];
                     gdata->hashBuckets[hashIndex] = tinfo;
                 }
                 /* Break out */
                 break;
            }
            prev = tinfo;
            tinfo = tinfo->next;
        }

        /* If we didn't find anything we need to enter a new entry */
        if ( tinfo == NULL ) {
            /* Create new hash table element */
            tinfo = newTraceInfo(trace, hashCode, flavor);
        }

        /* Update stats */
        (void)updateStats(tinfo);
    
    } exitCriticalSection(jvmti);
    
    return tinfo;
}

/* Get TraceInfo for this allocation */
static TraceInfo *
findTraceInfo(jvmtiEnv *jvmti, jthread thread, TraceFlavor flavor)
{
    TraceInfo *tinfo;
    jvmtiError error;
    
    tinfo = NULL;
    if ( thread != NULL ) {
        static Trace  empty;
        Trace         trace;

        /* Before VM_INIT thread could be NULL, watch out */
        trace = empty;
        error = (*jvmti)->GetStackTrace(jvmti, thread, 0, MAX_FRAMES+2,
                            trace.frames, &(trace.nframes));
        /* If we get a PHASE error, the VM isn't ready, or it died */
        if ( error == JVMTI_ERROR_WRONG_PHASE ) {
            /* It is assumed this is before VM_INIT */
            if ( flavor == TRACE_USER ) {
                tinfo = emptyTrace(TRACE_BEFORE_VM_INIT);
            } else {
                tinfo = emptyTrace(flavor);
            }
        } else {
            check_jvmti_error(jvmti, error, "Cannot get stack trace");
            /* Lookup this entry */
            tinfo = lookupOrEnter(jvmti, &trace, flavor);
        }
    } else {
        /* If thread==NULL, it's assumed this is before VM_START */
        if ( flavor == TRACE_USER ) {
            tinfo = emptyTrace(TRACE_BEFORE_VM_START);
        } else {
            tinfo = emptyTrace(flavor);
        }
    }
    return tinfo;
}

/* Tag an object with a TraceInfo pointer. */
static void
tagObjectWithTraceInfo(jvmtiEnv *jvmti, jobject object, TraceInfo *tinfo)
{
    jvmtiError error;