/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Reference table management.
*/
#include "Dalvik.h"
/*
* Initialize a ReferenceTable structure.
*/
bool dvmInitReferenceTable(ReferenceTable* pRef, int initialCount,
int maxCount)
{
assert(initialCount > 0);
assert(initialCount <= maxCount);
pRef->table = (Object**) malloc(initialCount * sizeof(Object*));
if (pRef->table == NULL)
return false;
#ifndef NDEBUG
memset(pRef->table, 0xdd, initialCount * sizeof(Object*));
#endif
pRef->nextEntry = pRef->table;
pRef->allocEntries = initialCount;
pRef->maxEntries = maxCount;
return true;
}
/*
* Clears out the contents of a ReferenceTable, freeing allocated storage.
*/
void dvmClearReferenceTable(ReferenceTable* pRef)
{
free(pRef->table);
pRef->table = pRef->nextEntry = NULL;
pRef->allocEntries = pRef->maxEntries = -1;
}
/*
* Add "obj" to "pRef".
*/
bool dvmAddToReferenceTable(ReferenceTable* pRef, Object* obj)
{
assert(dvmIsValidObject(obj));
assert(obj != NULL);
assert(pRef->table != NULL);
assert(pRef->allocEntries <= pRef->maxEntries);
if (pRef->nextEntry == pRef->table + pRef->allocEntries) {
/* reached end of allocated space; did we hit buffer max? */
if (pRef->nextEntry == pRef->table + pRef->maxEntries) {
LOGW("ReferenceTable overflow (max=%d)\n", pRef->maxEntries);
return false;
}
Object** newTable;
int newSize;
newSize = pRef->allocEntries * 2;
if (newSize > pRef->maxEntries)
newSize = pRef->maxEntries;
assert(newSize > pRef->allocEntries);
newTable = (Object**) realloc(pRef->table, newSize * sizeof(Object*));
if (newTable == NULL) {
LOGE("Unable to expand ref table (from %d to %d %d-byte entries)\n",
pRef->allocEntries, newSize, sizeof(Object*));
return false;
}
LOGVV("Growing %p from %d to %d\n", pRef, pRef->allocEntries, newSize);
/* update entries; adjust "nextEntry" in case memory moved */
pRef->nextEntry = newTable + (pRef->nextEntry - pRef->table);
pRef->table = newTable;
pRef->allocEntries = newSize;
}
*pRef->nextEntry++ = obj;
return true;
}
/*
* Returns NULL if not found.
*/
Object** dvmFindInReferenceTable(const ReferenceTable* pRef, Object** bottom,
Object* obj)
{
Object** ptr;
ptr = pRef->nextEntry;
while (--ptr >= bottom) {
if (*ptr == obj)
return ptr;
}
return NULL;
}
/*
* Remove "obj" from "pRef". We start at the end of the list (where the
* most-recently-added element is), and stop searching for a match after
* examining the element at "bottom".
*
* Most of the time "obj" is at or near the end of the list. If not, we
* compact it down.
*/
bool dvmRemoveFromReferenceTable(ReferenceTable* pRef, Object** bottom,
Object* obj)
{
Object** ptr;
assert(pRef->table != NULL);
/*
* Scan from the most-recently-added entry up to the bottom entry for
* this frame.
*/
ptr = dvmFindInReferenceTable(pRef, bottom, obj);
if (ptr == NULL)
return false;
/*
* Delete the entry.
*/
pRef->nextEntry--;
int moveCount = pRef->nextEntry - ptr;
if (moveCount != 0) {
/* remove from middle, slide the rest down */
memmove(ptr, ptr+1, moveCount * sizeof(Object*));
//LOGV("LREF delete %p, shift %d down\n", obj, moveCount);
} else {
/* last entry, falls off the end */
//LOGV("LREF delete %p from end\n", obj);
}
return true;
}
/*
* This is a qsort() callback. We sort Object* by class, allocation size,
* and then by the Object* itself.
*/
static int compareObject(const void* vobj1, const void* vobj2)
{
Object* obj1 = *((Object**) vobj1);
Object* obj2 = *((Object**) vobj2);
if (obj1 == NULL || obj2 == NULL)
return (u1*)obj1 - (u1*)obj2;
if (obj1->clazz != obj2->clazz) {
return (u1*)obj1->clazz - (u1*)obj2->clazz;
} else {
int size1 = dvmObjectSizeInHeap(obj1);
int size2 = dvmObjectSizeInHeap(obj2);
if (size1 != size2) {
return size1 - size2;
} else {
return (u1*)obj1 - (u1*)obj2;
}
}
}
/*
* Log an object with some additional info.
*
* Pass in the number of additional elements that are identical to or
* equivalent to the original.
*/
static void logObject(Object* obj, int size, int identical, int equiv)
{
if (obj == NULL) {
LOGW(" NULL reference (count=%d)\n", equiv);
return;
}
/* handle "raw" dvmMalloc case */
const char* descriptor =
(obj->clazz != NULL) ? obj->clazz->descriptor : "(raw)";
if (identical + equiv != 0) {
LOGW("%5d of %s %dB (%d unique)\n", identical + equiv +1,
descriptor, size, equiv +1);
} else {
LOGW("%5d of %s %dB\n", identical + equiv +1, descriptor, size);
}
}
/*
* Dump the contents of a ReferenceTable to the log.
*
* The caller should lock any external sync before calling.
*
* (This was originally written to be tolerant of null entries in the table.
* I don't think that can happen anymore.)
*/
void dvmDumpReferenceTable(const ReferenceTable* pRef, const char* descr)
{
const int kLast = 10;
int count = dvmReferenceTableEntries(pRef);
Object** refs;
int i;
if (count == 0) {
LOGW("%s reference table has no entries\n", descr);
return;
}
assert(count > 0);
/*
* Dump the most recent N entries.
*/
LOGW("Last %d entries in %s reference table:\n", kLast, descr);
refs = pRef->table; // use unsorted list
int size;
int start = count - kLast;
if (start < 0)
start = 0;
for (i = start; i < count; i++) {
size = (refs[i] == NULL) ? 0 : dvmObjectSizeInHeap(refs[i]);
Object* ref = refs[i];
if (ref->clazz == gDvm.classJavaLangClass) {
ClassObject* clazz = (ClassObject*) ref;
LOGW("%5d: %p cls=%s '%s' (%d bytes)\n", i, ref,
(refs[i] == NULL) ? "-" : ref->clazz->descriptor,
clazz->descriptor, size);
} else if (ref->clazz == NULL) {
/* should only be possible right after a plain dvmMalloc() */
LOGW("%5d: %p cls=(raw) (%d bytes)\n", i, ref, size);
} else {
LOGW("%5d: %p cls=%s (%d bytes)\n", i, ref,
(refs[i] == NULL) ? "-" : ref->clazz->descriptor, size);
}
}
/*
* Make a copy of the table, and sort it.
*/
Object** tableCopy = (Object**)malloc(sizeof(Object*) * count);
memcpy(tableCopy, pRef->table, sizeof(Object*) * count);
qsort(tableCopy, count, sizeof(Object*), compareObject);
refs = tableCopy; // use sorted list
/*
* Dump uniquified table summary. While we're at it, generate a
* cumulative total amount of pinned memory based on the unique entries.
*/
LOGW("%s reference table summary (%d entries):\n", descr, count);
int equiv, identical, total;
total = equiv = identical = 0;
for (i = 1; i < count; i++) {
size = (refs[i-1] == NULL) ? 0 : dvmObjectSizeInHeap(refs[i-1]);
if (refs[i] == refs[i-1]) {
/* same reference, added more than once */
identical++;
} else if (refs[i]->clazz == refs[i-1]->clazz &&
(int) dvmObjectSizeInHeap(refs[i]) == size)
{
/* same class / size, different object */
total += size;
equiv++;
} else {
/* different class */
total += size;
logObject(refs[i-1], size, identical, equiv);
equiv = identical = 0;
}
}
/* handle the last entry (everything above outputs refs[i-1]) */
size = (refs[count-1] == NULL) ? 0 : dvmObjectSizeInHeap(refs[count-1]);
total += size;
logObject(refs[count-1], size, identical, equiv);
LOGW("Memory held directly by tracked refs is %d bytes\n", total);
free(tableCopy);
}