/*
* Copyright (c) 1999-2007 Apple Inc. All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/***********************************************************************
* objc-cache.m
* Method cache management
* Cache flushing
* Cache garbage collection
* Cache instrumentation
* Dedicated allocator for large caches
**********************************************************************/
/***********************************************************************
* Method cache locking (GrP 2001-1-14)
*
* For speed, objc_msgSend does not acquire any locks when it reads
* method caches. Instead, all cache changes are performed so that any
* objc_msgSend running concurrently with the cache mutator will not
* crash or hang or get an incorrect result from the cache.
*
* When cache memory becomes unused (e.g. the old cache after cache
* expansion), it is not immediately freed, because a concurrent
* objc_msgSend could still be using it. Instead, the memory is
* disconnected from the data structures and placed on a garbage list.
* The memory is now only accessible to instances of objc_msgSend that
* were running when the memory was disconnected; any further calls to
* objc_msgSend will not see the garbage memory because the other data
* structures don't point to it anymore. The collecting_in_critical
* function checks the PC of all threads and returns FALSE when all threads
* are found to be outside objc_msgSend. This means any call to objc_msgSend
* that could have had access to the garbage has finished or moved past the
* cache lookup stage, so it is safe to free the memory.
*
* All functions that modify cache data or structures must acquire the
* cacheUpdateLock to prevent interference from concurrent modifications.
* The function that frees cache garbage must acquire the cacheUpdateLock
* and use collecting_in_critical() to flush out cache readers.
* The cacheUpdateLock is also used to protect the custom allocator used
* for large method cache blocks.
*
* Cache readers (PC-checked by collecting_in_critical())
* objc_msgSend*
* _cache_getImp
* _cache_getMethod
*
* Cache writers (hold cacheUpdateLock while reading or writing; not PC-checked)
* _cache_fill (acquires lock)
* _cache_expand (only called from cache_fill)
* _cache_create (only called from cache_expand)
* bcopy (only called from instrumented cache_expand)
* flush_caches (acquires lock)
* _cache_flush (only called from cache_fill and flush_caches)
* _cache_collect_free (only called from cache_expand and cache_flush)
*
* UNPROTECTED cache readers (NOT thread-safe; used for debug info only)
* _cache_print
* _class_printMethodCaches
* _class_printDuplicateCacheEntries
* _class_printMethodCacheStatistics
*
* _class_lookupMethodAndLoadCache is a special case. It may read a
* method triplet out of one cache and store it in another cache. This
* is unsafe if the method triplet is a forward:: entry, because the
* triplet itself could be freed unless _class_lookupMethodAndLoadCache
* were PC-checked or used a lock. Additionally, storing the method
* triplet in both caches would result in double-freeing if both caches
* were flushed or expanded. The solution is for _cache_getMethod to
* ignore all entries whose implementation is _objc_msgForward_impcache,
* so _class_lookupMethodAndLoadCache cannot look at a forward:: entry
* unsafely or place it in multiple caches.
***********************************************************************/
#if !__OBJC2__
#include "objc-private.h"
#include "objc-cache-old.h"
#include "hashtable2.h"
typedef struct {
SEL name; // same layout as struct old_method
void *unused;
IMP imp; // same layout as struct old_method
} cache_entry;
/* When _class_slow_grow is non-zero, any given cache is actually grown
* only on the odd-numbered times it becomes full; on the even-numbered
* times, it is simply emptied and re-used. When this flag is zero,
* caches are grown every time. */
static const int _class_slow_grow = 1;
/* For min cache size: clear_cache=1, slow_grow=1
For max cache size: clear_cache=0, slow_grow=0 */
/* Initial cache bucket count. INIT_CACHE_SIZE must be a power of two. */
enum {
INIT_CACHE_SIZE_LOG2 = 2,
INIT_CACHE_SIZE = (1 << INIT_CACHE_SIZE_LOG2)
};
/* Amount of space required for `count` hash table buckets, knowing that
* one entry is embedded in the cache structure itself. */
#define TABLE_SIZE(count) ((count - 1) * sizeof(cache_entry *))
#if !TARGET_OS_WIN32
# define CACHE_ALLOCATOR
#endif
/* Custom cache allocator parameters.
* CACHE_REGION_SIZE must be a multiple of CACHE_QUANTUM. */
#define CACHE_ALLOCATOR_MIN 512
#define CACHE_QUANTUM (CACHE_ALLOCATOR_MIN+sizeof(struct objc_cache)-sizeof(cache_entry*))
#define CACHE_REGION_SIZE ((128*1024 / CACHE_QUANTUM) * CACHE_QUANTUM)
// #define CACHE_REGION_SIZE ((256*1024 / CACHE_QUANTUM) * CACHE_QUANTUM)
static uintptr_t cache_allocator_mask_for_size(size_t size)
{
return (size - sizeof(struct objc_cache)) / sizeof(cache_entry *);
}
static size_t cache_allocator_size_for_mask(uintptr_t mask)
{
size_t requested = sizeof(struct objc_cache) + TABLE_SIZE(mask+1);
size_t actual = CACHE_QUANTUM;
while (actual < requested) actual += CACHE_QUANTUM;
return actual;
}
/* Cache instrumentation data. Immediately follows the cache block itself. */
#ifdef OBJC_INSTRUMENTED
typedef struct
{
unsigned int hitCount; // cache lookup success tally
unsigned int hitProbes; // sum entries checked to hit
unsigned int maxHitProbes; // max entries checked to hit
unsigned int missCount; // cache lookup no-find tally
unsigned int missProbes; // sum entries checked to miss
unsigned int maxMissProbes; // max entries checked to miss
unsigned int flushCount; // cache flush tally
unsigned int flushedEntries; // sum cache entries flushed
unsigned int maxFlushedEntries; // max cache entries flushed
} CacheInstrumentation;
#define CACHE_INSTRUMENTATION(cache) (CacheInstrumentation *) &cache->buckets[cache->mask + 1];
#endif
/* Cache filling and flushing instrumentation */
static int totalCacheFills = 0;
#ifdef OBJC_INSTRUMENTED
unsigned int LinearFlushCachesCount = 0;
unsigned int LinearFlushCachesVisitedCount = 0;
unsigned int MaxLinearFlushCachesVisitedCount = 0;
unsigned int NonlinearFlushCachesCount = 0;
unsigned int NonlinearFlushCachesClassCount = 0;
unsigned int NonlinearFlushCachesVisitedCount = 0;
unsigned int MaxNonlinearFlushCachesVisitedCount = 0;
unsigned int IdealFlushCachesCount = 0;
unsigned int MaxIdealFlushCachesCount = 0;
#endif
/***********************************************************************
* A static empty cache. All classes initially point at this cache.
* When the first message is sent it misses in the cache, and when
* the cache is grown it checks for this case and uses malloc rather
* than realloc. This avoids the need to check for NULL caches in the
* messenger.
***********************************************************************/
struct objc_cache _objc_empty_cache =
{
0, // mask
0, // occupied
{ NULL } // buckets
};
#ifdef OBJC_INSTRUMENTED
CacheInstrumentation emptyCacheInstrumentation = {0};
#endif
/* Local prototypes */
static BOOL _cache_isEmpty(Cache cache);
static Cache _cache_malloc(uintptr_t slotCount);
static Cache _cache_create(Class cls);
static Cache _cache_expand(Class cls);
static int _collecting_in_critical(void);
static void _garbage_make_room(void);
static void _cache_collect_free(void *data, size_t size);
#if defined(CACHE_ALLOCATOR)
static BOOL cache_allocator_is_block(void *block);
static Cache cache_allocator_calloc(size_t size);
static void cache_allocator_free(void *block);
#endif
/***********************************************************************
* Cache statistics for OBJC_PRINT_CACHE_SETUP
**********************************************************************/
static unsigned int cache_counts[16];
static size_t cache_allocations;
static size_t cache_collections;
static size_t cache_allocator_regions;
static size_t log2u(size_t x)
{
unsigned int log;
log = 0;
while (x >>= 1)
log += 1;
return log;
}
/***********************************************************************
* _cache_isEmpty.
* Returns YES if the given cache is some empty cache.
* Empty caches should never be allocated on the heap.
**********************************************************************/
static BOOL _cache_isEmpty(Cache cache)
{
return (cache == NULL || cache == (Cache)&_objc_empty_cache || cache->mask == 0);
}
/***********************************************************************
* _cache_malloc.
*
* Called from _cache_create() and cache_expand()
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static Cache _cache_malloc(uintptr_t slotCount)
{
Cache new_cache;
size_t size;
mutex_assert_locked(&cacheUpdateLock);
// Allocate table (why not check for failure?)
size = sizeof(struct objc_cache) + TABLE_SIZE(slotCount);
#if defined(OBJC_INSTRUMENTED)
// Custom cache allocator can't handle instrumentation.
size += sizeof(CacheInstrumentation);
new_cache = _calloc_internal(size, 1);
new_cache->mask = slotCount - 1;
#elif !defined(CACHE_ALLOCATOR)
// fixme cache allocator implementation isn't 64-bit clean
new_cache = _calloc_internal(size, 1);
new_cache->mask = (unsigned int)(slotCount - 1);
#else
if (size < CACHE_ALLOCATOR_MIN || UseInternalZone) {
new_cache = (Cache)_calloc_internal(size, 1);
new_cache->mask = slotCount - 1;
// occupied and buckets and instrumentation are all zero
} else {
new_cache = cache_allocator_calloc(size);
// mask is already set
// occupied and buckets and instrumentation are all zero
}
#endif
if (PrintCaches) {
size_t bucket = log2u(slotCount);
if (bucket < sizeof(cache_counts) / sizeof(cache_counts[0])) {
cache_counts[bucket]++;
}
cache_allocations++;
}
return new_cache;
}
/***********************************************************************
* _cache_free_block.
*
* Called from _cache_free() and _cache_collect_free().
* block may be a cache or a forward:: entry.
* If block is a cache, forward:: entries it points to will NOT be freed.
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static inline int isPowerOf2(unsigned long l) { return 1 == __builtin_popcountl(l); }
static void _cache_free_block(void *block)
{
mutex_assert_locked(&cacheUpdateLock);
#if !TARGET_OS_WIN32
if (PrintCaches) {
Cache cache = (Cache)block;
size_t slotCount = cache->mask + 1;
if (isPowerOf2(slotCount)) {
size_t bucket = log2u(slotCount);
if (bucket < sizeof(cache_counts) / sizeof(cache_counts[0])) {
cache_counts[bucket]--;
}
}
}
#endif
#if defined(CACHE_ALLOCATOR)
if (cache_allocator_is_block(block)) {
cache_allocator_free(block);
} else
#endif
{
free(block);
}
}
/***********************************************************************
* _cache_free.
*
* Called from _objc_remove_classes_in_image().
* forward:: entries in the cache ARE freed.
* Cache locks: cacheUpdateLock must NOT be held by the caller.
**********************************************************************/
void _cache_free(Cache cache)
{
unsigned int i;
mutex_lock(&cacheUpdateLock);
for (i = 0; i < cache->mask + 1; i++) {
cache_entry *entry = (cache_entry *)cache->buckets[i];
if (entry && entry->imp == _objc_msgForward_impcache) {
_cache_free_block(entry);
}
}
_cache_free_block(cache);
mutex_unlock(&cacheUpdateLock);
}
/***********************************************************************
* _cache_create.
*
* Called from _cache_expand().
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static Cache _cache_create(Class cls)
{
Cache new_cache;
mutex_assert_locked(&cacheUpdateLock);
// Allocate new cache block
new_cache = _cache_malloc(INIT_CACHE_SIZE);
// Install the cache
cls->cache = new_cache;
// Clear the grow flag so that we will re-use the current storage,
// rather than actually grow the cache, when expanding the cache
// for the first time
if (_class_slow_grow) {
cls->setShouldGrowCache(false);
}
// Return our creation
return new_cache;
}
/***********************************************************************
* _cache_expand.
*
* Called from _cache_fill ()
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static Cache _cache_expand(Class cls)
{
Cache old_cache;
Cache new_cache;
uintptr_t slotCount;
uintptr_t index;
mutex_assert_locked(&cacheUpdateLock);
// First growth goes from empty cache to a real one
old_cache = cls->cache;
if (_cache_isEmpty(old_cache))
return _cache_create (cls);
if (_class_slow_grow) {
// Cache grows every other time only.
if (cls->shouldGrowCache()) {
// Grow the cache this time. Don't grow next time.
cls->setShouldGrowCache(false);
}
else {
// Reuse the current cache storage this time. Do grow next time.
cls->setShouldGrowCache(true);
// Clear the valid-entry counter
old_cache->occupied = 0;
// Invalidate all the cache entries
for (index = 0; index < old_cache->mask + 1; index += 1)
{
// Remember what this entry was, so we can possibly
// deallocate it after the bucket has been invalidated
cache_entry *oldEntry = (cache_entry *)old_cache->buckets[index];
// Skip invalid entry
if (!oldEntry)
continue;
// Invalidate this entry
old_cache->buckets[index] = NULL;
// Deallocate "forward::" entry
if (oldEntry->imp == _objc_msgForward_impcache) {
_cache_collect_free (oldEntry, sizeof(cache_entry));
}
}
// Return the same old cache, freshly emptied
return old_cache;
}
}
// Double the cache size
slotCount = (old_cache->mask + 1) << 1;
new_cache = _cache_malloc(slotCount);
#ifdef OBJC_INSTRUMENTED
// Propagate the instrumentation data
{
CacheInstrumentation *oldCacheData;
CacheInstrumentation *newCacheData;
oldCacheData = CACHE_INSTRUMENTATION(old_cache);
newCacheData = CACHE_INSTRUMENTATION(new_cache);
bcopy ((const char *)oldCacheData, (char *)newCacheData, sizeof(CacheInstrumentation));
}
#endif
// Deallocate "forward::" entries from the old cache
for (index = 0; index < old_cache->mask + 1; index++) {
cache_entry *entry = (cache_entry *)old_cache->buckets[index];
if (entry && entry->imp == _objc_msgForward_impcache) {
_cache_collect_free (entry, sizeof(cache_entry));
}
}
// Install new cache
cls->cache = new_cache;
// Deallocate old cache, try freeing all the garbage
_cache_collect_free (old_cache, old_cache->mask * sizeof(cache_entry *));
_cache_collect(false);
return new_cache;
}
/***********************************************************************
* _cache_fill. Add the specified method to the specified class' cache.
* Returns NO if the cache entry wasn't added: cache was busy,
* class is still being initialized, new entry is a duplicate.
*
* Called only from _class_lookupMethodAndLoadCache and
* class_respondsToMethod and _cache_addForwardEntry.
*
* Cache locks: cacheUpdateLock must not be held.
**********************************************************************/
BOOL _cache_fill(Class cls, Method smt, SEL sel)
{
uintptr_t newOccupied;
uintptr_t index;
cache_entry **buckets;
cache_entry *entry;
Cache cache;
mutex_assert_unlocked(&cacheUpdateLock);
// Never cache before +initialize is done
if (!cls->isInitialized()) {
return NO;
}
// Keep tally of cache additions
totalCacheFills += 1;
mutex_lock(&cacheUpdateLock);
entry = (cache_entry *)smt;
cache = cls->cache;
// Make sure the entry wasn't added to the cache by some other thread
// before we grabbed the cacheUpdateLock.
// Don't use _cache_getMethod() because _cache_getMethod() doesn't
// return forward:: entries.
if (_cache_getImp(cls, sel)) {
mutex_unlock(&cacheUpdateLock);
return NO; // entry is already cached, didn't add new one
}
// Use the cache as-is if it is less than 3/4 full
newOccupied = cache->occupied + 1;
if ((newOccupied * 4) <= (cache->mask + 1) * 3) {
// Cache is less than 3/4 full.
cache->occupied = (unsigned int)newOccupied;
} else {
// Cache is too full. Expand it.
cache = _cache_expand (cls);
// Account for the addition
cache->occupied += 1;
}
// Scan for the first unused slot and insert there.
// There is guaranteed to be an empty slot because the
// minimum size is 4 and we resized at 3/4 full.
buckets = (cache_entry **)cache->buckets;
for (index = CACHE_HASH(sel, cache->mask);
buckets[index] != NULL;
index = (index+1) & cache->mask)
{
// empty
}
buckets[index] = entry;
mutex_unlock(&cacheUpdateLock);
return YES; // successfully added new cache entry
}
/***********************************************************************
* _cache_addForwardEntry
* Add a forward:: entry for the given selector to cls's method cache.
* Does nothing if the cache addition fails for any reason.
* Called from class_respondsToMethod and _class_lookupMethodAndLoadCache.
* Cache locks: cacheUpdateLock must not be held.
**********************************************************************/
void _cache_addForwardEntry(Class cls, SEL sel)
{
cache_entry *smt;
smt = (cache_entry *)_malloc_internal(sizeof(cache_entry));
smt->name = sel;
smt->imp = _objc_msgForward_impcache;
if (! _cache_fill(cls, (Method)smt, sel)) { // fixme hack
// Entry not added to cache. Don't leak the method struct.
_free_internal(smt);
}
}
/***********************************************************************
* _cache_addIgnoredEntry
* Add an entry for the ignored selector to cls's method cache.
* Does nothing if the cache addition fails for any reason.
* Returns the ignored IMP.
* Cache locks: cacheUpdateLock must not be held.
**********************************************************************/
#if SUPPORT_GC && !SUPPORT_IGNORED_SELECTOR_CONSTANT
static cache_entry *alloc_ignored_entries(void)
{
cache_entry *e = (cache_entry *)_malloc_internal(5 * sizeof(cache_entry));
e[0] = (cache_entry){ @selector(retain), 0,(IMP)&_objc_ignored_method};
e[1] = (cache_entry){ @selector(release), 0,(IMP)&_objc_ignored_method};
e[2] = (cache_entry){ @selector(autorelease),0,(IMP)&_objc_ignored_method};
e[3] = (cache_entry){ @selector(retainCount),0,(IMP)&_objc_ignored_method};
e[4] = (cache_entry){ @selector(dealloc), 0,(IMP)&_objc_ignored_method};
return e;
}
#endif
IMP _cache_addIgnoredEntry(Class cls, SEL sel)
{
cache_entry *entryp = NULL;
#if !SUPPORT_GC
_objc_fatal("selector ignored with GC off");
#elif SUPPORT_IGNORED_SELECTOR_CONSTANT
static cache_entry entry = { (SEL)kIgnore, 0, (IMP)&_objc_ignored_method };
entryp = &entry;
assert(sel == (SEL)kIgnore);
#else
// hack
int i;
static cache_entry *entries;
INIT_ONCE_PTR(entries, alloc_ignored_entries(), free(v));
assert(ignoreSelector(sel));
for (i = 0; i < 5; i++) {
if (sel == entries[i].name) {
entryp = &entries[i];
break;
}
}
if (!entryp) _objc_fatal("selector %s (%p) is not ignored",
sel_getName(sel), sel);
#endif
_cache_fill(cls, (Method)entryp, sel);
return entryp->imp;
}
/***********************************************************************
* _cache_flush. Invalidate all valid entries in the given class' cache.
*
* Called from flush_caches() and _cache_fill()
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
void _cache_flush(Class cls)
{
Cache cache;
unsigned int index;
mutex_assert_locked(&cacheUpdateLock);
// Locate cache. Ignore unused cache.
cache = cls->cache;
if (_cache_isEmpty(cache)) return;
#ifdef OBJC_INSTRUMENTED
{
CacheInstrumentation *cacheData;
// Tally this flush
cacheData = CACHE_INSTRUMENTATION(cache);
cacheData->flushCount += 1;
cacheData->flushedEntries += cache->occupied;
if (cache->occupied > cacheData->maxFlushedEntries)
cacheData->maxFlushedEntries = cache->occupied;
}
#endif
// Traverse the cache
for (index = 0; index <= cache->mask; index += 1)
{
// Remember what this entry was, so we can possibly
// deallocate it after the bucket has been invalidated
cache_entry *oldEntry = (cache_entry *)cache->buckets[index];
// Invalidate this entry
cache->buckets[index] = NULL;
// Deallocate "forward::" entry
if (oldEntry && oldEntry->imp == _objc_msgForward_impcache)
_cache_collect_free (oldEntry, sizeof(cache_entry));
}
// Clear the valid-entry counter
cache->occupied = 0;
}
/***********************************************************************
* flush_cache. Flushes the instance method cache for class cls only.
* Use flush_caches() if cls might have in-use subclasses.
**********************************************************************/
void flush_cache(Class cls)
{
if (cls) {
mutex_lock(&cacheUpdateLock);
_cache_flush(cls);
mutex_unlock(&cacheUpdateLock);
}
}
/***********************************************************************
* cache collection.
**********************************************************************/
#if !TARGET_OS_WIN32
// A sentinel (magic value) to report bad thread_get_state status.
// Must not be a valid PC.
// Must not be zero - thread_get_state() on a new thread returns PC == 0.
#define PC_SENTINEL 1
// UNIX03 compliance hack (4508809)
#if !__DARWIN_UNIX03
#define __srr0 srr0
#define __eip eip
#endif
static uintptr_t _get_pc_for_thread(thread_t thread)
#if defined(__i386__)
{
i386_thread_state_t state;
unsigned int count = i386_THREAD_STATE_COUNT;
kern_return_t okay = thread_get_state (thread, i386_THREAD_STATE, (thread_state_t)&state, &count);
return (okay == KERN_SUCCESS) ? state.__eip : PC_SENTINEL;
}
#elif defined(__x86_64__)
{
x86_thread_state64_t state;
unsigned int count = x86_THREAD_STATE64_COUNT;
kern_return_t okay = thread_get_state (thread, x86_THREAD_STATE64, (thread_state_t)&state, &count);
return (okay == KERN_SUCCESS) ? state.__rip : PC_SENTINEL;
}
#elif defined(__arm__)
{
arm_thread_state_t state;
unsigned int count = ARM_THREAD_STATE_COUNT;
kern_return_t okay = thread_get_state (thread, ARM_THREAD_STATE, (thread_state_t)&state, &count);
return (okay == KERN_SUCCESS) ? state.__pc : PC_SENTINEL;
}
#else
{
#error _get_pc_for_thread () not implemented for this architecture
}
#endif
#endif
/***********************************************************************
* _collecting_in_critical.
* Returns TRUE if some thread is currently executing a cache-reading
* function. Collection of cache garbage is not allowed when a cache-
* reading function is in progress because it might still be using
* the garbage memory.
**********************************************************************/
OBJC_EXPORT uintptr_t objc_entryPoints[];
OBJC_EXPORT uintptr_t objc_exitPoints[];
static int _collecting_in_critical(void)
{
#if TARGET_OS_WIN32
return TRUE;
#else
thread_act_port_array_t threads;
unsigned number;
unsigned count;
kern_return_t ret;
int result;
mach_port_t mythread = pthread_mach_thread_np(pthread_self());
// Get a list of all the threads in the current task
ret = task_threads (mach_task_self (), &threads, &number);
if (ret != KERN_SUCCESS)
{
_objc_fatal("task_thread failed (result %d)\n", ret);
}
// Check whether any thread is in the cache lookup code
result = FALSE;
for (count = 0; count < number; count++)
{
int region;
uintptr_t pc;
// Don't bother checking ourselves
if (threads[count] == mythread)
continue;
// Find out where thread is executing
pc = _get_pc_for_thread (threads[count]);
// Check for bad status, and if so, assume the worse (can't collect)
if (pc == PC_SENTINEL)
{
result = TRUE;
goto done;
}
// Check whether it is in the cache lookup code
for (region = 0; objc_entryPoints[region] != 0; region++)
{
if ((pc >= objc_entryPoints[region]) &&
(pc <= objc_exitPoints[region]))
{
result = TRUE;
goto done;
}
}
}
done:
// Deallocate the port rights for the threads
for (count = 0; count < number; count++) {
mach_port_deallocate(mach_task_self (), threads[count]);
}
// Deallocate the thread list
vm_deallocate (mach_task_self (), (vm_address_t) threads, sizeof(threads[0]) * number);
// Return our finding
return result;
#endif
}
/***********************************************************************
* _garbage_make_room. Ensure that there is enough room for at least
* one more ref in the garbage.
**********************************************************************/
// amount of memory represented by all refs in the garbage
static size_t garbage_byte_size = 0;
// do not empty the garbage until garbage_byte_size gets at least this big
static size_t garbage_threshold = 1024;
// table of refs to free
static void **garbage_refs = 0;
// current number of refs in garbage_refs
static size_t garbage_count = 0;
// capacity of current garbage_refs
static size_t garbage_max = 0;
// capacity of initial garbage_refs
enum {
INIT_GARBAGE_COUNT = 128
};
static void _garbage_make_room(void)
{
static int first = 1;
// Create the collection table the first time it is needed
if (first)
{
first = 0;
garbage_refs = (void**)
_malloc_internal(INIT_GARBAGE_COUNT * sizeof(void *));
garbage_max = INIT_GARBAGE_COUNT;
}
// Double the table if it is full
else if (garbage_count == garbage_max)
{
garbage_refs = (void**)
_realloc_internal(garbage_refs, garbage_max * 2 * sizeof(void *));
garbage_max *= 2;
}
}
/***********************************************************************
* _cache_collect_free. Add the specified malloc'd memory to the list
* of them to free at some later point.
* size is used for the collection threshold. It does not have to be
* precisely the block's size.
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static void _cache_collect_free(void *data, size_t size)
{
mutex_assert_locked(&cacheUpdateLock);
_garbage_make_room ();
garbage_byte_size += size;
garbage_refs[garbage_count++] = data;
}
/***********************************************************************
* _cache_collect. Try to free accumulated dead caches.
* collectALot tries harder to free memory.
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
void _cache_collect(bool collectALot)
{
mutex_assert_locked(&cacheUpdateLock);
// Done if the garbage is not full
if (garbage_byte_size < garbage_threshold && !collectALot) {
return;
}
// Synchronize collection with objc_msgSend and other cache readers
if (!collectALot) {
if (_collecting_in_critical ()) {
// objc_msgSend (or other cache reader) is currently looking in
// the cache and might still be using some garbage.
if (PrintCaches) {
_objc_inform ("CACHES: not collecting; "
"objc_msgSend in progress");
}
return;
}
}
else {
// No excuses.
while (_collecting_in_critical())
;
}
// No cache readers in progress - garbage is now deletable
// Log our progress
if (PrintCaches) {
cache_collections++;
_objc_inform ("CACHES: COLLECTING %zu bytes (%zu regions, %zu allocations, %zu collections)", garbage_byte_size, cache_allocator_regions, cache_allocations, cache_collections);
}
// Dispose all refs now in the garbage
while (garbage_count--) {
_cache_free_block(garbage_refs[garbage_count]);
}
// Clear the garbage count and total size indicator
garbage_count = 0;
garbage_byte_size = 0;
if (PrintCaches) {
size_t i;
size_t total = 0;
size_t ideal_total = 0;
size_t malloc_total = 0;
size_t local_total = 0;
for (i = 0; i < sizeof(cache_counts) / sizeof(cache_counts[0]); i++) {
int count = cache_counts[i];
int slots = 1 << i;
size_t size = sizeof(struct objc_cache) + TABLE_SIZE(slots);
size_t ideal = size;
#if TARGET_OS_WIN32
size_t malloc = size;
#else
size_t malloc = malloc_good_size(size);
#endif
size_t local = size < CACHE_ALLOCATOR_MIN ? malloc : cache_allocator_size_for_mask(cache_allocator_mask_for_size(size));
if (!count) continue;
_objc_inform("CACHES: %4d slots: %4d caches, %6zu / %6zu / %6zu bytes ideal/malloc/local, %6zu / %6zu bytes wasted malloc/local", slots, count, ideal*count, malloc*count, local*count, malloc*count-ideal*count, local*count-ideal*count);
total += count;
ideal_total += ideal*count;
malloc_total += malloc*count;
local_total += local*count;
}
_objc_inform("CACHES: total: %4zu caches, %6zu / %6zu / %6zu bytes ideal/malloc/local, %6zu / %6zu bytes wasted malloc/local", total, ideal_total, malloc_total, local_total, malloc_total-ideal_total, local_total-ideal_total);
}
}
#if defined(CACHE_ALLOCATOR)
/***********************************************************************
* Custom method cache allocator.
* Method cache block sizes are 2^slots+2 words, which is a pessimal
* case for the system allocator. It wastes 504 bytes per cache block
* with 128 or more slots, which adds up to tens of KB for an AppKit process.
* To save memory, the custom cache allocator below is used.
*
* The cache allocator uses 128 KB allocation regions. Few processes will
* require a second region. Within a region, allocation is address-ordered
* first fit.
*
* The cache allocator uses a quantum of 520.
* Cache block ideal sizes: 520, 1032, 2056, 4104
* Cache allocator sizes: 520, 1040, 2080, 4160
*
* Because all blocks are known to be genuine method caches, the ordinary
* cache->mask and cache->occupied fields are used as block headers.
* No out-of-band headers are maintained. The number of blocks will
* almost always be fewer than 200, so for simplicity there is no free
* list or other optimization.
*
* Block in use: mask != 0, occupied != -1 (mask indicates block size)
* Block free: mask != 0, occupied == -1 (mask is precisely block size)
*
* No cache allocator functions take any locks. Instead, the caller
* must hold the cacheUpdateLock.
*
* fixme with 128 KB regions and 520 B min block size, an allocation
* bitmap would be only 32 bytes - better than free list?
**********************************************************************/
typedef struct cache_allocator_block {
uintptr_t size;
uintptr_t state;
struct cache_allocator_block *nextFree;
} cache_allocator_block;
typedef struct cache_allocator_region {
cache_allocator_block *start;
cache_allocator_block *end; // first non-block address
cache_allocator_block *freeList;
struct cache_allocator_region *next;
} cache_allocator_region;
static cache_allocator_region *cacheRegion = NULL;
/***********************************************************************
* cache_allocator_add_region
* Allocates and returns a new region that can hold at least size
* bytes of large method caches.
* The actual size will be rounded up to a CACHE_QUANTUM boundary,
* with a minimum of CACHE_REGION_SIZE.
* The new region is lowest-priority for new allocations. Callers that
* know the other regions are already full should allocate directly
* into the returned region.
**********************************************************************/
static cache_allocator_region *cache_allocator_add_region(size_t size)
{
vm_address_t addr;
cache_allocator_block *b;
cache_allocator_region **rgnP;
cache_allocator_region *newRegion = (cache_allocator_region *)
_calloc_internal(1, sizeof(cache_allocator_region));
// Round size up to quantum boundary, and apply the minimum size.
size += CACHE_QUANTUM - (size % CACHE_QUANTUM);
if (size < CACHE_REGION_SIZE) size = CACHE_REGION_SIZE;
// Allocate the region
addr = (vm_address_t)calloc(size, 1);
newRegion->start = (cache_allocator_block *)addr;
newRegion->end = (cache_allocator_block *)(addr + size);
// Mark the first block: free and covers the entire region
b = newRegion->start;
b->size = size;
b->state = (uintptr_t)-1;
b->nextFree = NULL;
newRegion->freeList = b;
// Add to end of the linked list of regions.
// Other regions should be re-used before this one is touched.
newRegion->next = NULL;
rgnP = &cacheRegion;
while (*rgnP) {
rgnP = &(**rgnP).next;
}
*rgnP = newRegion;
cache_allocator_regions++;
return newRegion;
}
/***********************************************************************
* cache_allocator_coalesce
* Attempts to coalesce a free block with the single free block following
* it in the free list, if any.
**********************************************************************/
static void cache_allocator_coalesce(cache_allocator_block *block)
{
if (block->size + (uintptr_t)block == (uintptr_t)block->nextFree) {
block->size += block->nextFree->size;
block->nextFree = block->nextFree->nextFree;
}
}
/***********************************************************************
* cache_region_calloc
* Attempt to allocate a size-byte block in the given region.
* Allocation is first-fit. The free list is already fully coalesced.
* Returns NULL if there is not enough room in the region for the block.
**********************************************************************/
static void *cache_region_calloc(cache_allocator_region *rgn, size_t size)
{
cache_allocator_block **blockP;
uintptr_t mask;
// Save mask for allocated block, then round size
// up to CACHE_QUANTUM boundary
mask = cache_allocator_mask_for_size(size);
size = cache_allocator_size_for_mask(mask);
// Search the free list for a sufficiently large free block.
for (blockP = &rgn->freeList;
*blockP != NULL;
blockP = &(**blockP).nextFree)
{
cache_allocator_block *block = *blockP;
if (block->size < size) continue; // not big enough
// block is now big enough. Allocate from it.
// Slice off unneeded fragment of block, if any,
// and reconnect the free list around block.
if (block->size - size >= CACHE_QUANTUM) {
cache_allocator_block *leftover =
(cache_allocator_block *)(size + (uintptr_t)block);
leftover->size = block->size - size;
leftover->state = (uintptr_t)-1;
leftover->nextFree = block->nextFree;
*blockP = leftover;
} else {
*blockP = block->nextFree;
}
// block is now exactly the right size.
bzero(block, size);
block->size = mask; // Cache->mask
block->state = 0; // Cache->occupied
return block;
}
// No room in this region.
return NULL;
}
/***********************************************************************
* cache_allocator_calloc
* Custom allocator for large method caches (128+ slots)
* The returned cache block already has cache->mask set.
* cache->occupied and the cache contents are zero.
* Cache locks: cacheUpdateLock must be held by the caller
**********************************************************************/
static Cache cache_allocator_calloc(size_t size)
{
cache_allocator_region *rgn;
mutex_assert_locked(&cacheUpdateLock);
for (rgn = cacheRegion; rgn != NULL; rgn = rgn->next) {
void *p = cache_region_calloc(rgn, size);
if (p) {
return (Cache)p;
}
}
// No regions or all regions full - make a region and try one more time
// In the unlikely case of a cache over 256KB, it will get its own region.
return (Cache)cache_region_calloc(cache_allocator_add_region(size), size);
}
/***********************************************************************
* cache_allocator_region_for_block
* Returns the cache allocator region that ptr points into, or NULL.
**********************************************************************/
static cache_allocator_region *cache_allocator_region_for_block(cache_allocator_block *block)
{
cache_allocator_region *rgn;
for (rgn = cacheRegion; rgn != NULL; rgn = rgn->next) {
if (block >= rgn->start && block < rgn->end) return rgn;
}
return NULL;
}
/***********************************************************************
* cache_allocator_is_block
* If ptr is a live block from the cache allocator, return YES
* If ptr is a block from some other allocator, return NO.
* If ptr is a dead block from the cache allocator, result is undefined.
* Cache locks: cacheUpdateLock must be held by the caller
**********************************************************************/
static BOOL cache_allocator_is_block(void *ptr)
{
mutex_assert_locked(&cacheUpdateLock);
return (cache_allocator_region_for_block((cache_allocator_block *)ptr) != NULL);
}
/***********************************************************************
* cache_allocator_free
* Frees a block allocated by the cache allocator.
* Cache locks: cacheUpdateLock must be held by the caller.
**********************************************************************/
static void cache_allocator_free(void *ptr)
{
cache_allocator_block *dead = (cache_allocator_block *)ptr;
cache_allocator_block *cur;
cache_allocator_region *rgn;
mutex_assert_locked(&cacheUpdateLock);
if (! (rgn = cache_allocator_region_for_block(dead))) {
// free of non-pointer
_objc_inform("cache_allocator_free of non-pointer %p", dead);
return;
}
dead->size = cache_allocator_size_for_mask(dead->size);
dead->state = (uintptr_t)-1;
if (!rgn->freeList || rgn->freeList > dead) {
// dead block belongs at front of free list
dead->nextFree = rgn->freeList;
rgn->freeList = dead;
cache_allocator_coalesce(dead);
return;
}
// dead block belongs in the middle or end of free list
for (cur = rgn->freeList; cur != NULL; cur = cur->nextFree) {
cache_allocator_block *ahead = cur->nextFree;
if (!ahead || ahead > dead) {
// cur and ahead straddle dead, OR dead belongs at end of free list
cur->nextFree = dead;
dead->nextFree = ahead;
// coalesce into dead first in case both succeed
cache_allocator_coalesce(dead);
cache_allocator_coalesce(cur);
return;
}
}
// uh-oh
_objc_inform("cache_allocator_free of non-pointer %p", ptr);
}
// defined(CACHE_ALLOCATOR)
#endif
/***********************************************************************
* Cache instrumentation and debugging
**********************************************************************/
#ifdef OBJC_INSTRUMENTED
enum {
CACHE_HISTOGRAM_SIZE = 512
};
unsigned int CacheHitHistogram [CACHE_HISTOGRAM_SIZE];
unsigned int CacheMissHistogram [CACHE_HISTOGRAM_SIZE];
#endif
/***********************************************************************
* _cache_print.
**********************************************************************/
static void _cache_print(Cache cache)
{
uintptr_t index;
uintptr_t count;
count = cache->mask + 1;
for (index = 0; index < count; index += 1) {
cache_entry *entry = (cache_entry *)cache->buckets[index];
if (entry) {
if (entry->imp == _objc_msgForward_impcache)
printf ("does not recognize: \n");
printf ("%s\n", sel_getName(entry->name));
}
}
}
/***********************************************************************
* _class_printMethodCaches.
**********************************************************************/
void _class_printMethodCaches(Class cls)
{
if (_cache_isEmpty(cls->cache)) {
printf("no instance-method cache for class %s\n",cls->nameForLogging());
} else {
printf("instance-method cache for class %s:\n", cls->nameForLogging());
_cache_print(cls->cache);
}
if (_cache_isEmpty(cls->ISA()->cache)) {
printf("no class-method cache for class %s\n", cls->nameForLogging());
} else {
printf ("class-method cache for class %s:\n", cls->nameForLogging());
_cache_print(cls->ISA()->cache);
}
}
#if 0
#warning fixme
/***********************************************************************
* _class_printDuplicateCacheEntries.
**********************************************************************/
void _class_printDuplicateCacheEntries(BOOL detail)
{
NXHashState state;
Class cls;
unsigned int duplicates;
unsigned int index1;
unsigned int index2;
unsigned int mask;
unsigned int count;
unsigned int isMeta;
Cache cache;
printf ("Checking for duplicate cache entries \n");
// Outermost loop - iterate over all classes
state = NXInitHashState (class_hash);
duplicates = 0;
while (NXNextHashState (class_hash, &state, (void **) &cls))
{
// Control loop - do given class' cache, then its isa's cache
for (isMeta = 0; isMeta <= 1; isMeta += 1)
{
// Select cache of interest and make sure it exists
cache = (isMeta ? cls->ISA : cls)->cache;
if (_cache_isEmpty(cache))
continue;
// Middle loop - check each entry in the given cache
mask = cache->mask;
count = mask + 1;
for (index1 = 0; index1 < count; index1 += 1)
{
// Skip invalid entry
if (!cache->buckets[index1])
continue;
// Inner loop - check that given entry matches no later entry
for (index2 = index1 + 1; index2 < count; index2 += 1)
{
// Skip invalid entry
if (!cache->buckets[index2])
continue;
// Check for duplication by method name comparison
if (strcmp ((char *) cache->buckets[index1]->name),
(char *) cache->buckets[index2]->name)) == 0)
{
if (detail)
printf ("%s %s\n", cls->nameForLogging(), sel_getName(cache->buckets[index1]->name));
duplicates += 1;
break;
}
}
}
}
}
// Log the findings
printf ("duplicates = %d\n", duplicates);
printf ("total cache fills = %d\n", totalCacheFills);
}
/***********************************************************************
* PrintCacheHeader.
**********************************************************************/
static void PrintCacheHeader(void)
{
#ifdef OBJC_INSTRUMENTED
printf ("Cache Cache Slots Avg Max AvgS MaxS AvgS MaxS TotalD AvgD MaxD TotalD AvgD MaxD TotD AvgD MaxD\n");
printf ("Size Count Used Used Used Hit Hit Miss Miss Hits Prbs Prbs Misses Prbs Prbs Flsh Flsh Flsh\n");
printf ("----- ----- ----- ----- ---- ---- ---- ---- ---- ------- ---- ---- ------- ---- ---- ---- ---- ----\n");
#else
printf ("Cache Cache Slots Avg Max AvgS MaxS AvgS MaxS\n");
printf ("Size Count Used Used Used Hit Hit Miss Miss\n");
printf ("----- ----- ----- ----- ---- ---- ---- ---- ----\n");
#endif
}
/***********************************************************************
* PrintCacheInfo.
**********************************************************************/
static void PrintCacheInfo(unsigned int cacheSize,
unsigned int cacheCount,
unsigned int slotsUsed,
float avgUsed, unsigned int maxUsed,
float avgSHit, unsigned int maxSHit,
float avgSMiss, unsigned int maxSMiss
#ifdef OBJC_INSTRUMENTED
, unsigned int totDHits,
float avgDHit,
unsigned int maxDHit,
unsigned int totDMisses,
float avgDMiss,
unsigned int maxDMiss,
unsigned int totDFlsh,
float avgDFlsh,
unsigned int maxDFlsh
#endif
)
{
#ifdef OBJC_INSTRUMENTED
printf ("%5u %5u %5u %5.1f %4u %4.1f %4u %4.1f %4u %7u %4.1f %4u %7u %4.1f %4u %4u %4.1f %4u\n",
#else
printf ("%5u %5u %5u %5.1f %4u %4.1f %4u %4.1f %4u\n",
#endif
cacheSize, cacheCount, slotsUsed, avgUsed, maxUsed, avgSHit, maxSHit, avgSMiss, maxSMiss
#ifdef OBJC_INSTRUMENTED
, totDHits, avgDHit, maxDHit, totDMisses, avgDMiss, maxDMiss, totDFlsh, avgDFlsh, maxDFlsh
#endif
);
}
#ifdef OBJC_INSTRUMENTED
/***********************************************************************
* PrintCacheHistogram. Show the non-zero entries from the specified
* cache histogram.
**********************************************************************/
static void PrintCacheHistogram(char *title,
unsigned int *firstEntry,
unsigned int entryCount)
{
unsigned int index;
unsigned int *thisEntry;
printf ("%s\n", title);
printf (" Probes Tally\n");
printf (" ------ -----\n");
for (index = 0, thisEntry = firstEntry;
index < entryCount;
index += 1, thisEntry += 1)
{
if (*thisEntry == 0)
continue;
printf (" %6d %5d\n", index, *thisEntry);
}
}
#endif
/***********************************************************************
* _class_printMethodCacheStatistics.
**********************************************************************/
#define MAX_LOG2_SIZE 32
#define MAX_CHAIN_SIZE 100
void _class_printMethodCacheStatistics(void)
{
unsigned int isMeta;
unsigned int index;
NXHashState state;
Class cls;
unsigned int totalChain;
unsigned int totalMissChain;
unsigned int maxChain;
unsigned int maxMissChain;
unsigned int classCount;
unsigned int negativeEntryCount;
unsigned int cacheExpandCount;
unsigned int cacheCountBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int totalEntriesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxEntriesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int totalChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int totalMissChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int totalMaxChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int totalMaxMissChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxMissChainBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int chainCount[MAX_CHAIN_SIZE] = {0};
unsigned int missChainCount[MAX_CHAIN_SIZE] = {0};
#ifdef OBJC_INSTRUMENTED
unsigned int hitCountBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int hitProbesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxHitProbesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int missCountBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int missProbesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxMissProbesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int flushCountBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int flushedEntriesBySize[2][MAX_LOG2_SIZE] = {{0}};
unsigned int maxFlushedEntriesBySize[2][MAX_LOG2_SIZE] = {{0}};
#endif
printf ("Printing cache statistics\n");
// Outermost loop - iterate over all classes
state = NXInitHashState (class_hash);
classCount = 0;
negativeEntryCount = 0;
cacheExpandCount = 0;
while (NXNextHashState (class_hash, &state, (void **) &cls))
{
// Tally classes
classCount += 1;
// Control loop - do given class' cache, then its isa's cache
for (isMeta = 0; isMeta <= 1; isMeta += 1)
{
Cache cache;
unsigned int mask;
unsigned int log2Size;
unsigned int entryCount;
// Select cache of interest
cache = (isMeta ? cls->ISA : cls)->cache;
// Ignore empty cache... should we?
if (_cache_isEmpty(cache))
continue;
// Middle loop - do each entry in the given cache
mask = cache->mask;
entryCount = 0;
totalChain = 0;
totalMissChain = 0;
maxChain = 0;
maxMissChain = 0;
for (index = 0; index < mask + 1; index += 1)
{
cache_entry **buckets;
cache_entry *entry;
unsigned int hash;
unsigned int methodChain;
unsigned int methodMissChain;
unsigned int index2;
// If entry is invalid, the only item of
// interest is that future insert hashes
// to this entry can use it directly.
buckets = (cache_entry **)cache->buckets;
if (!buckets[index])
{
missChainCount[0] += 1;
continue;
}
entry = buckets[index];
// Tally valid entries
entryCount += 1;
// Tally "forward::" entries
if (entry->imp == _objc_msgForward_impcache)
negativeEntryCount += 1;
// Calculate search distance (chain length) for this method
// The chain may wrap around to the beginning of the table.
hash = CACHE_HASH(entry->name, mask);
if (index >= hash) methodChain = index - hash;
else methodChain = (mask+1) + index - hash;
// Tally chains of this length
if (methodChain < MAX_CHAIN_SIZE)
chainCount[methodChain] += 1;
// Keep sum of all chain lengths
totalChain += methodChain;
// Record greatest chain length
if (methodChain > maxChain)
maxChain = methodChain;
// Calculate search distance for miss that hashes here
index2 = index;
while (buckets[index2])
{
index2 += 1;
index2 &= mask;
}
methodMissChain = ((index2 - index) & mask);
// Tally miss chains of this length
if (methodMissChain < MAX_CHAIN_SIZE)
missChainCount[methodMissChain] += 1;
// Keep sum of all miss chain lengths in this class
totalMissChain += methodMissChain;
// Record greatest miss chain length
if (methodMissChain > maxMissChain)
maxMissChain = methodMissChain;
}
// Factor this cache into statistics about caches of the same
// type and size (all caches are a power of two in size)
log2Size = log2u (mask + 1);
cacheCountBySize[isMeta][log2Size] += 1;
totalEntriesBySize[isMeta][log2Size] += entryCount;
if (entryCount > maxEntriesBySize[isMeta][log2Size])
maxEntriesBySize[isMeta][log2Size] = entryCount;
totalChainBySize[isMeta][log2Size] += totalChain;
totalMissChainBySize[isMeta][log2Size] += totalMissChain;
totalMaxChainBySize[isMeta][log2Size] += maxChain;
totalMaxMissChainBySize[isMeta][log2Size] += maxMissChain;
if (maxChain > maxChainBySize[isMeta][log2Size])
maxChainBySize[isMeta][log2Size] = maxChain;
if (maxMissChain > maxMissChainBySize[isMeta][log2Size])
maxMissChainBySize[isMeta][log2Size] = maxMissChain;
#ifdef OBJC_INSTRUMENTED
{
CacheInstrumentation *cacheData;
cacheData = CACHE_INSTRUMENTATION(cache);
hitCountBySize[isMeta][log2Size] += cacheData->hitCount;
hitProbesBySize[isMeta][log2Size] += cacheData->hitProbes;
if (cacheData->maxHitProbes > maxHitProbesBySize[isMeta][log2Size])
maxHitProbesBySize[isMeta][log2Size] = cacheData->maxHitProbes;
missCountBySize[isMeta][log2Size] += cacheData->missCount;
missProbesBySize[isMeta][log2Size] += cacheData->missProbes;
if (cacheData->maxMissProbes > maxMissProbesBySize[isMeta][log2Size])
maxMissProbesBySize[isMeta][log2Size] = cacheData->maxMissProbes;
flushCountBySize[isMeta][log2Size] += cacheData->flushCount;
flushedEntriesBySize[isMeta][log2Size] += cacheData->flushedEntries;
if (cacheData->maxFlushedEntries > maxFlushedEntriesBySize[isMeta][log2Size])
maxFlushedEntriesBySize[isMeta][log2Size] = cacheData->maxFlushedEntries;
}
#endif
// Caches start with a power of two number of entries, and grow by doubling, so
// we can calculate the number of times this cache has expanded
cacheExpandCount += log2Size - INIT_CACHE_SIZE_LOG2;
}
}
{
unsigned int cacheCountByType[2] = {0};
unsigned int totalCacheCount = 0;
unsigned int totalEntries = 0;
unsigned int maxEntries = 0;
unsigned int totalSlots = 0;
#ifdef OBJC_INSTRUMENTED
unsigned int totalHitCount = 0;
unsigned int totalHitProbes = 0;
unsigned int maxHitProbes = 0;
unsigned int totalMissCount = 0;
unsigned int totalMissProbes = 0;
unsigned int maxMissProbes = 0;
unsigned int totalFlushCount = 0;
unsigned int totalFlushedEntries = 0;
unsigned int maxFlushedEntries = 0;
#endif
totalChain = 0;
maxChain = 0;
totalMissChain = 0;
maxMissChain = 0;
// Sum information over all caches
for (isMeta = 0; isMeta <= 1; isMeta += 1)
{
for (index = 0; index < MAX_LOG2_SIZE; index += 1)
{
cacheCountByType[isMeta] += cacheCountBySize[isMeta][index];
totalEntries += totalEntriesBySize[isMeta][index];
totalSlots += cacheCountBySize[isMeta][index] * (1 << index);
totalChain += totalChainBySize[isMeta][index];
if (maxEntriesBySize[isMeta][index] > maxEntries)
maxEntries = maxEntriesBySize[isMeta][index];
if (maxChainBySize[isMeta][index] > maxChain)
maxChain = maxChainBySize[isMeta][index];
totalMissChain += totalMissChainBySize[isMeta][index];
if (maxMissChainBySize[isMeta][index] > maxMissChain)
maxMissChain = maxMissChainBySize[isMeta][index];
#ifdef OBJC_INSTRUMENTED
totalHitCount += hitCountBySize[isMeta][index];
totalHitProbes += hitProbesBySize[isMeta][index];
if (maxHitProbesBySize[isMeta][index] > maxHitProbes)
maxHitProbes = maxHitProbesBySize[isMeta][index];
totalMissCount += missCountBySize[isMeta][index];
totalMissProbes += missProbesBySize[isMeta][index];
if (maxMissProbesBySize[isMeta][index] > maxMissProbes)
maxMissProbes = maxMissProbesBySize[isMeta][index];
totalFlushCount += flushCountBySize[isMeta][index];
totalFlushedEntries += flushedEntriesBySize[isMeta][index];
if (maxFlushedEntriesBySize[isMeta][index] > maxFlushedEntries)
maxFlushedEntries = maxFlushedEntriesBySize[isMeta][index];
#endif
}
totalCacheCount += cacheCountByType[isMeta];
}
// Log our findings
printf ("There are %u classes\n", classCount);
for (isMeta = 0; isMeta <= 1; isMeta += 1)
{
// Number of this type of class
printf ("\nThere are %u %s-method caches, broken down by size (slot count):\n",
cacheCountByType[isMeta],
isMeta ? "class" : "instance");
// Print header
PrintCacheHeader ();
// Keep format consistent even if there are caches of this kind
if (cacheCountByType[isMeta] == 0)
{
printf ("(none)\n");
continue;
}
// Usage information by cache size
for (index = 0; index < MAX_LOG2_SIZE; index += 1)
{
unsigned int cacheCount;
unsigned int cacheSlotCount;
unsigned int cacheEntryCount;
// Get number of caches of this type and size
cacheCount = cacheCountBySize[isMeta][index];
if (cacheCount == 0)
continue;
// Get the cache slot count and the total number of valid entries
cacheSlotCount = (1 << index);
cacheEntryCount = totalEntriesBySize[isMeta][index];
// Give the analysis
PrintCacheInfo (cacheSlotCount,
cacheCount,
cacheEntryCount,
(float) cacheEntryCount / (float) cacheCount,
maxEntriesBySize[isMeta][index],
(float) totalChainBySize[isMeta][index] / (float) cacheEntryCount,
maxChainBySize[isMeta][index],
(float) totalMissChainBySize[isMeta][index] / (float) (cacheCount * cacheSlotCount),
maxMissChainBySize[isMeta][index]
#ifdef OBJC_INSTRUMENTED
, hitCountBySize[isMeta][index],
hitCountBySize[isMeta][index] ?
(float) hitProbesBySize[isMeta][index] / (float) hitCountBySize[isMeta][index] : 0.0,
maxHitProbesBySize[isMeta][index],
missCountBySize[isMeta][index],
missCountBySize[isMeta][index] ?
(float) missProbesBySize[isMeta][index] / (float) missCountBySize[isMeta][index] : 0.0,
maxMissProbesBySize[isMeta][index],
flushCountBySize[isMeta][index],
flushCountBySize[isMeta][index] ?
(float) flushedEntriesBySize[isMeta][index] / (float) flushCountBySize[isMeta][index] : 0.0,
maxFlushedEntriesBySize[isMeta][index]
#endif
);
}
}
// Give overall numbers
printf ("\nCumulative:\n");
PrintCacheHeader ();
PrintCacheInfo (totalSlots,
totalCacheCount,
totalEntries,
(float) totalEntries / (float) totalCacheCount,
maxEntries,
(float) totalChain / (float) totalEntries,
maxChain,
(float) totalMissChain / (float) totalSlots,
maxMissChain
#ifdef OBJC_INSTRUMENTED
, totalHitCount,
totalHitCount ?
(float) totalHitProbes / (float) totalHitCount : 0.0,
maxHitProbes,
totalMissCount,
totalMissCount ?
(float) totalMissProbes / (float) totalMissCount : 0.0,
maxMissProbes,
totalFlushCount,
totalFlushCount ?
(float) totalFlushedEntries / (float) totalFlushCount : 0.0,
maxFlushedEntries
#endif
);
printf ("\nNumber of \"forward::\" entries: %d\n", negativeEntryCount);
printf ("Number of cache expansions: %d\n", cacheExpandCount);
#ifdef OBJC_INSTRUMENTED
printf ("flush_caches: total calls total visits average visits max visits total classes visits/class\n");
printf (" ----------- ------------ -------------- ---------- ------------- -------------\n");
printf (" linear %11u %12u %14.1f %10u %13u %12.2f\n",
LinearFlushCachesCount,
LinearFlushCachesVisitedCount,
LinearFlushCachesCount ?
(float) LinearFlushCachesVisitedCount / (float) LinearFlushCachesCount : 0.0,
MaxLinearFlushCachesVisitedCount,
LinearFlushCachesVisitedCount,
1.0);
printf (" nonlinear %11u %12u %14.1f %10u %13u %12.2f\n",
NonlinearFlushCachesCount,
NonlinearFlushCachesVisitedCount,
NonlinearFlushCachesCount ?
(float) NonlinearFlushCachesVisitedCount / (float) NonlinearFlushCachesCount : 0.0,
MaxNonlinearFlushCachesVisitedCount,
NonlinearFlushCachesClassCount,
NonlinearFlushCachesClassCount ?
(float) NonlinearFlushCachesVisitedCount / (float) NonlinearFlushCachesClassCount : 0.0);
printf (" ideal %11u %12u %14.1f %10u %13u %12.2f\n",
LinearFlushCachesCount + NonlinearFlushCachesCount,
IdealFlushCachesCount,
LinearFlushCachesCount + NonlinearFlushCachesCount ?
(float) IdealFlushCachesCount / (float) (LinearFlushCachesCount + NonlinearFlushCachesCount) : 0.0,
MaxIdealFlushCachesCount,
LinearFlushCachesVisitedCount + NonlinearFlushCachesClassCount,
LinearFlushCachesVisitedCount + NonlinearFlushCachesClassCount ?
(float) IdealFlushCachesCount / (float) (LinearFlushCachesVisitedCount + NonlinearFlushCachesClassCount) : 0.0);
PrintCacheHistogram ("\nCache hit histogram:", &CacheHitHistogram[0], CACHE_HISTOGRAM_SIZE);
PrintCacheHistogram ("\nCache miss histogram:", &CacheMissHistogram[0], CACHE_HISTOGRAM_SIZE);
#endif
#if 0
printf ("\nLookup chains:");
for (index = 0; index < MAX_CHAIN_SIZE; index += 1)
{
if (chainCount[index] != 0)
printf (" %u:%u", index, chainCount[index]);
}
printf ("\nMiss chains:");
for (index = 0; index < MAX_CHAIN_SIZE; index += 1)
{
if (missChainCount[index] != 0)
printf (" %u:%u", index, missChainCount[index]);
}
printf ("\nTotal memory usage for cache data structures: %lu bytes\n",
totalCacheCount * (sizeof(struct objc_cache) - sizeof(cache_entry *)) +
totalSlots * sizeof(cache_entry *) +
negativeEntryCount * sizeof(cache_entry));
#endif
}
}
#endif
// !__OBJC2__
#endif