Annotation of objc/objc-sel.m, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
                      3:  *
                      4:  * @APPLE_LICENSE_HEADER_START@
                      5:  * 
                      6:  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
                      7:  * Reserved.  This file contains Original Code and/or Modifications of
                      8:  * Original Code as defined in and that are subject to the Apple Public
                      9:  * Source License Version 1.0 (the 'License').  You may not use this file
                     10:  * except in compliance with the License.  Please obtain a copy of the
                     11:  * License at http://www.apple.com/publicsource and read it before using
                     12:  * this file.
                     13:  * 
                     14:  * The Original Code and all software distributed under the License are
                     15:  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
                     16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
                     17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
                     18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
                     19:  * License for the specific language governing rights and limitations
                     20:  * under the License."
                     21:  * 
                     22:  * @APPLE_LICENSE_HEADER_END@
                     23:  */
                     24: /*
                     25:  *     objc-sel.m
                     26:  *     Copyright 1988, NeXT, Inc.
                     27:  *     Author: s. naroff
                     28:  *
                     29:  *     Public functions:               
                     30:  *     --------------
                     31:  *
                     32:  *     sel_getName
                     33:  *     sel_getUid
                     34:  *     sel_isMapped
                     35:  *     sel_registerName
                     36:  *     _strhash                        (undocumented)
                     37:  *
                     38:  *     Private functions:
                     39:  *     ---------------
                     40:  *
                     41:  *     _sel_init                       (private extern)
                     42:  *     _sel_unloadSelectors            (private extern)
                     43:  *
                     44:  */
                     45: 
                     46: #ifdef SHLIB
                     47: #import "shlib.h"
                     48: #endif SHLIB
                     49: 
                     50: #import "objc-private.h"
                     51: 
                     52: /* Number of hashtable buckets to malloc in a chunk */
                     53: 
                     54: #define HASH_ALLOC_LIST_SIZE 40
                     55: 
                     56: /* Size of the dynamic and freeze-dried hashtables */
                     57: 
                     58: #define SIZEHASHTABLE 821
                     59: 
                     60:    
                     61: typedef struct _hashEntry
                     62: {
                     63:   struct _hashEntry *next;
                     64:   const char *sel;
                     65: } HASH, *PHASH;
                     66: 
                     67: typedef struct _hashTable
                     68: {
                     69:   const struct mach_header *header;
                     70:   unsigned int count;
                     71:   unsigned int entries;
                     72:   const char *min;
                     73:   const char *max;
                     74:   PHASH *list;
                     75:   struct _hashTable *next;
                     76: } hashTable;
                     77: 
                     78: /* The dynamic hashtable contains all selectors which are not present in
                     79:    any freeze-dried hashtable.  Space for it is allocated only on demand.
                     80:    We use a sentinel to avoid extra tests for NULL. */
                     81: 
                     82: static const PHASH sentinel = NULL;
                     83: 
                     84: static hashTable dynamicHashTable =
                     85: {
                     86:   NULL,
                     87:   1,           // count
                     88:   0,           // entries
                     89:   NULL,                // Range checking does not work for the dynamic hashtable.
                     90:   NULL,
                     91:   (PHASH *) &sentinel,
                     92:   NULL,                // next
                     93: };
                     94: 
                     95: 
                     96: /* The list of all hashtables.  The freeze-dried hashtables are placed on
                     97:    the list in order of size, and the dynamic hashtable is always last. */
                     98: 
                     99: static hashTable *hashTableChain = &dynamicHashTable;
                    100: 
                    101: #ifndef FREEZE
                    102: /* Lock for all static data in objc-sel.m */
                    103: 
                    104: static OBJC_DECLARE_LOCK (selectorLock);
                    105: #endif
                    106: 
                    107: /* This is a duplicate of a static function in objc-class.m!  We should
                    108:    make this a private extern. */
                    109: 
                    110: static void *objc_malloc (unsigned int size)
                    111: {
                    112:   NXZone *zone;
                    113:   void *space;
                    114:   
                    115: #ifdef FREEZE
                    116:   zone = NXDefaultMallocZone ();
                    117: #else
                    118:   zone = _objc_create_zone ();
                    119: #endif
                    120:   
                    121:   space = NXZoneMalloc (zone, size);
                    122:   
                    123:   if (space == 0 && size != 0)
                    124:     __S(_objc_fatal) ("unable to allocate space");
                    125: 
                    126:   return space;
                    127: }
                    128: 
                    129: 
                    130: /* For compatibility only.  This function is public even though it never
                    131:    should have been. */
                    132: 
                    133: #ifndef FREEZE
                    134: unsigned int _strhash (const unsigned char *s)
                    135: {
                    136:   return _objc_strhash (s);
                    137: }
                    138: #endif
                    139: 
                    140: /* Allocate and initialize a new bucket for the dynamic hashtable.
                    141:    The selector lock is assumed to be already taken out. */
                    142: 
                    143: static inline PHASH opthashNew (const char *key, PHASH link)
                    144: {
                    145:   static PHASH HASH_alloc_list = 0;
                    146:   static int HASH_alloc_index = 0;
                    147:   PHASH new;
                    148: 
                    149:   if (!HASH_alloc_list || HASH_alloc_index >= HASH_ALLOC_LIST_SIZE)
                    150:     {
                    151:       HASH_alloc_list = objc_malloc (sizeof (HASH) * HASH_ALLOC_LIST_SIZE);
                    152:       HASH_alloc_index = 0;
                    153:     }
                    154:   
                    155:   new = &HASH_alloc_list[HASH_alloc_index++];
                    156:   new->next = link;
                    157:   new->sel = key;
                    158:   return new;
                    159: }
                    160: 
                    161: 
                    162: #ifndef FREEZE
                    163: /* This is no longer used.  We should remove this from the API. */
                    164: 
                    165: BOOL sel_isMapped (SEL sel)
                    166: {
                    167:   hashTable *table;
                    168:   
                    169:   if (sel == (SEL) 0) 
                    170:     return NO;
                    171:   
                    172:   OBJC_LOCK (&selectorLock);
                    173:   
                    174:   for (table = hashTableChain; table; table = table->next)
                    175:     {
                    176:       if ((const char *) sel >= table->min && (const char *) sel < table->max)
                    177:         {
                    178:          OBJC_UNLOCK (&selectorLock);
                    179:          return YES;
                    180:        }
                    181:       else if (table == &dynamicHashTable)
                    182:         {
                    183:          unsigned int slot;
                    184:          
                    185:          for (slot = 0; slot < table->count; slot++)
                    186:            {
                    187:              PHASH target;
                    188:              
                    189:              for (target = table->list[slot]; target; target = target->next)
                    190:                if (sel == (SEL)target->sel)
                    191:                  {
                    192:                    OBJC_UNLOCK (&selectorLock);
                    193:                    return YES;
                    194:                  }
                    195:            }
                    196:        }
                    197:     }
                    198:   
                    199:   OBJC_UNLOCK (&selectorLock);
                    200:   
                    201:   return NO;
                    202: }
                    203: #endif
                    204: 
                    205: #ifndef FREEZE
                    206: /* This is now very fast!
                    207:    Note that previously we would return NULL if passed an invalid selector. */
                    208: 
                    209: const char *sel_getName (SEL sel)
                    210: {
                    211:   return (const char *) sel;
                    212: }
                    213: #endif
                    214: 
                    215: /* Add a new selector if not already present.  Formerly _sel_registerName(). 
                    216:    Now again _sel_registerName(), and a public safe variant added. */
                    217: 
                    218: SEL __S(_sel_registerName) (const char *key)
                    219: {
                    220:   unsigned int hash;
                    221:   hashTable *table;
                    222:   
                    223:   if (!key) 
                    224:     return (SEL) 0;
                    225:   
                    226:   hash = _objc_strhash (key);
                    227:   
                    228:   OBJC_LOCK (&selectorLock);
                    229:   
                    230:   for (table = hashTableChain; table; table = table->next)
                    231:     {
                    232:       if (key >= table->min && key < table->max)
                    233:         {
                    234:          OBJC_UNLOCK (&selectorLock);
                    235:          return (SEL) key;
                    236:        }
                    237:       else
                    238:         {
                    239:          PHASH target;
                    240:          unsigned int slot = hash % table->count;
                    241:          
                    242:          for (target = table->list[slot]; target; target = target->next)
                    243:            if (key[0] == target->sel[0] &&
                    244:                strcmp (key, target->sel) == 0)
                    245:              {
                    246:                OBJC_UNLOCK (&selectorLock);
                    247:                return (SEL) target->sel;
                    248:              }
                    249:          
                    250:          /* If we have reached the dynamic hashtable, insert a new entry. */
                    251:          if (table == &dynamicHashTable)
                    252:            {
                    253:              table->entries++;
                    254:              
                    255:              /* Allocate hashtable if needed. */
                    256:              if (table->list == &sentinel)
                    257:                {
                    258:                  /* Allocate a new empty array. */
                    259:                  table->count = SIZEHASHTABLE;
                    260:                  table->list = objc_malloc (table->count * sizeof (PHASH));
                    261:                  bzero (table->list, table->count * sizeof (PHASH));
                    262:                  slot = hash % table->count;
                    263:                }
                    264:              
                    265:              table->list[slot] = opthashNew (key, table->list[slot]);
                    266:              OBJC_UNLOCK (&selectorLock);
                    267:              return (SEL) key;
                    268:            }
                    269:        }
                    270:     }
                    271:   
                    272:   /* We searched all hashtables without finding the dynamic hashtable! */
                    273:   abort ();
                    274: }
                    275: 
                    276: /*
                    277:  *  Public version of _sel_registerName, which assures that the
                    278:  *  argument key is copied if nessecary.
                    279:  */
                    280: 
                    281: #ifndef FREEZE
                    282: SEL sel_registerName (const char *key)
                    283: {
                    284:    SEL s = sel_getUid (key);
                    285:    if (s) 
                    286:      return s;
                    287:    else
                    288:      return __S(_sel_registerName) (NXUniqueString (key));
                    289: }
                    290: #endif
                    291: 
                    292: /* Remove all of the selectors associated with a dynamically loaded module.
                    293:   We currently leak the removed entries (because they are allocated in
                    294:   chunks).  We could instead build a free chain out of them to reuse. */
                    295: 
                    296: #ifndef FREEZE
                    297: void __S(_sel_unloadSelectors) (const char *min, const char *max)
                    298: {
                    299:   hashTable *table = &dynamicHashTable;
                    300:   unsigned int slot;
                    301:   
                    302:   OBJC_LOCK (&selectorLock);
                    303:   
                    304:   for (slot = 0; slot < table->count; slot++)
                    305:     {
                    306:       PHASH *ptr = &table->list[slot];
                    307:       
                    308:       while (*ptr)
                    309:         {
                    310:          PHASH target = *ptr;
                    311:          
                    312:          if (target->sel >= min && target->sel < max)
                    313:            *ptr = target->next;        /* Remove this entry */
                    314:          else
                    315:            ptr = &target->next;        /* Skip */
                    316:         }
                    317:     }
                    318:   
                    319:   OBJC_UNLOCK (&selectorLock);
                    320: }
                    321: #endif
                    322: 
                    323: /* Search each hashtable in the chain for the string. */
                    324: 
                    325: #ifndef FREEZE
                    326: SEL sel_getUid (const char *key)
                    327: {
                    328:   unsigned int hash;
                    329:   hashTable *table;
                    330:   
                    331:   if (!key) 
                    332:     return (SEL) 0;
                    333:   
                    334:   hash = _objc_strhash (key);
                    335:   
                    336:   OBJC_LOCK (&selectorLock);
                    337:   
                    338:   for (table = hashTableChain; table; table = table->next)
                    339:     {
                    340:       if (key >= table->min && key < table->max)
                    341:         {
                    342:          OBJC_UNLOCK (&selectorLock);
                    343:          return (SEL) key;
                    344:        }
                    345:       else
                    346:         {
                    347:          PHASH target;
                    348:          unsigned int slot = hash % table->count;
                    349:          
                    350:          for (target = table->list[slot]; target; target = target->next)
                    351:            if (key[0] == target->sel[0] &&
                    352:                strcmp (key, target->sel) == 0)
                    353:              {
                    354:                OBJC_UNLOCK (&selectorLock);
                    355:                return (SEL) target->sel;
                    356:              }
                    357:        }
                    358:     }
                    359:   
                    360:   OBJC_UNLOCK (&selectorLock);
                    361:   
                    362:   return (SEL) 0;
                    363: }
                    364: #endif
                    365: 
                    366: /* Register a freeze-dried hashtable. */
                    367: 
                    368: void __S(_sel_init) (const struct mach_header *header,
                    369:                const char *strings,
                    370:                unsigned int stringSize,
                    371:                void *frozenHashTable)
                    372: {
                    373:   hashTable *frozenTable = NXZoneMalloc (NXDefaultMallocZone(), sizeof (hashTable));
                    374:   hashTable **tablePtr;
                    375:   
                    376:   frozenTable->header = header;
                    377:   frozenTable->count = SIZEHASHTABLE;
                    378:   frozenTable->entries = 0;
                    379:   frozenTable->min = strings;
                    380:   frozenTable->max = strings + stringSize;
                    381:   frozenTable->list = frozenHashTable;
                    382:   
                    383:   /* Insert the freeze-dried hashtable at the end of the hashtable chain. */
                    384:   
                    385:   for (tablePtr = &hashTableChain; *tablePtr; tablePtr = &(*tablePtr)->next)
                    386:     if (*tablePtr == &dynamicHashTable)
                    387:       {
                    388:         frozenTable->next = &dynamicHashTable;
                    389:        *tablePtr = frozenTable;
                    390:        break;
                    391:       }
                    392: }
                    393: 
                    394: 
                    395: #if  !defined(KERNEL) && !defined(FREEZE)
                    396: 
                    397: void _sel_printHashTable (void)
                    398: {
                    399:   hashTable *table;
                    400:   
                    401:   for (table = hashTableChain; table; table = table->next)
                    402:     {
                    403:       unsigned int slot;
                    404:       
                    405:       printf ("%s selector hashtable for %s:\n",
                    406:              (table == &dynamicHashTable) ? "dynamic" : "freeze-dried",
                    407:              __S(_nameForHeader) (table->header));
                    408:       
                    409:       printf ("\n");
                    410:       
                    411:       for (slot = 0; slot < table->count; slot++)
                    412:        {
                    413:          PHASH target;
                    414:          
                    415:          printf ("slot[%u]: ", slot);
                    416:          
                    417:          for (target = table->list[slot]; target; target = target->next)
                    418:            printf (" %s", target->sel);
                    419:          
                    420:          printf ("\n");
                    421:        }
                    422:       
                    423:       printf ("\n");
                    424:     }
                    425: }
                    426: 
                    427: 
                    428: void _sel_printStatistics (void)
                    429: {
                    430:   hashTable *table;
                    431:   unsigned int totalCount = 0;
                    432:   unsigned int totalEntries = 0;
                    433:   unsigned int totalUniqueEntries = 0;
                    434:   unsigned int totalEmptySlots = 0;
                    435:   unsigned int grandTotalChain = 0;
                    436:   unsigned int grandTotalMissChain = 0;
                    437:   unsigned int maxMaxChain = 0;
                    438:   unsigned int maxMaxMissChain = 0;
                    439:   unsigned int totalMallocedData = 0;
                    440:   unsigned int totalSharedData = 0;
                    441:   unsigned int depth = 0;
                    442:   unsigned int totalDepth = 0;
                    443:   
                    444:   for (table = hashTableChain; table; table = table->next)
                    445:     {
                    446:       unsigned int slot;
                    447:       unsigned int entries = 0;
                    448:       unsigned int uniqueEntries = 0;
                    449:       unsigned int emptySlots = 0;
                    450:       unsigned int totalChain = 0;
                    451:       unsigned int totalMissChain = 0;
                    452:       unsigned int maxChain = 0;
                    453:       unsigned int maxMissChain = 0;
                    454:       unsigned int mallocedData;
                    455:       unsigned int sharedData;
                    456:       
                    457:       for (slot = 0; slot < table->count; slot++)
                    458:        {
                    459:          PHASH target;
                    460:          unsigned int chain = 0;
                    461:          
                    462:          for (target = table->list[slot]; target; target = target->next)
                    463:            {
                    464:              entries++;
                    465:              
                    466:              if (sel_getUid (target->sel) == (SEL) target->sel)
                    467:                {
                    468:                  uniqueEntries++;
                    469:              
                    470:                  chain++;
                    471:                  
                    472:                  if (chain > maxChain)
                    473:                    maxChain = chain;
                    474:                  
                    475:                  totalChain += chain;
                    476:                }
                    477:            }
                    478:          
                    479:          if (chain > maxMissChain)
                    480:            maxMissChain = chain;
                    481:          
                    482:          totalMissChain += chain;
                    483:          
                    484:          if (chain == 0)
                    485:            emptySlots++;
                    486:        }
                    487:       
                    488:       printf ("%s selector hashtable for %s (depth = %u):\n",
                    489:              (table == &dynamicHashTable) ? "dynamic" : "freeze-dried",
                    490:              __S(_nameForHeader) (table->header),
                    491:              depth);
                    492:       
                    493:       printf ("%u entries in %u slots (%.2f entries/slot)\n",
                    494:              entries, table->count, (float) entries / (float) table->count);
                    495:       printf ("%u empty slots (%u%%)\n",
                    496:              emptySlots, (100 * emptySlots + 50) / table->count);
                    497:       printf ("%u redundant entries (%u%%)\n",
                    498:              entries - uniqueEntries,
                    499:              (100 * (entries - uniqueEntries) + 50) / entries);
                    500:       printf ("%.2f average lookup chain (%u maximum)\n",
                    501:              (float) totalChain / (float) uniqueEntries, maxChain);
                    502:       printf ("%.2f average miss chain (%u maximum)\n",
                    503:              (float) totalMissChain / (float) table->count, maxMissChain);
                    504:       if (table == &dynamicHashTable)
                    505:        {
                    506:          unsigned int chunks = (entries + HASH_ALLOC_LIST_SIZE - 1) /
                    507:                                HASH_ALLOC_LIST_SIZE;
                    508:          
                    509:          mallocedData = table->count * sizeof (PHASH) +
                    510:                         chunks * HASH_ALLOC_LIST_SIZE * sizeof (HASH);
                    511:          sharedData = 0;
                    512:        }
                    513:       else
                    514:         {
                    515:          mallocedData = sizeof (hashTable);
                    516:          sharedData = table->count * sizeof (PHASH) + entries * sizeof (HASH);
                    517:         }
                    518:       
                    519:       if (sharedData)
                    520:        printf ("%u bytes malloced data + %u bytes shared data\n",
                    521:                mallocedData, sharedData);
                    522:       else
                    523:        printf ("%u bytes malloced data\n", mallocedData);
                    524:       
                    525:       totalCount += table->count;
                    526:       totalEntries += entries;
                    527:       totalUniqueEntries += uniqueEntries;
                    528:       totalEmptySlots += emptySlots;
                    529:       grandTotalChain += totalChain;
                    530:       grandTotalMissChain += totalMissChain;
                    531:       if (maxChain > maxMaxChain)
                    532:         maxMaxChain = maxChain;
                    533:       if (maxMissChain > maxMaxMissChain)
                    534:         maxMaxMissChain = maxMissChain;
                    535:       totalMallocedData += mallocedData;
                    536:       totalSharedData += sharedData;
                    537:       totalDepth += depth * uniqueEntries;
                    538:       depth++;
                    539:       
                    540:       printf ("\n");
                    541:     }
                    542:   
                    543:   printf ("cummulative selector hashtable statistics:\n");
                    544:   
                    545:   printf ("%u entries in %u slots (%.2f entries/slot)\n",
                    546:          totalEntries, totalCount, (float) totalEntries / (float) totalCount);
                    547:   printf ("%u empty slots (%u%%)\n",
                    548:          totalEmptySlots, (100 * totalEmptySlots + 50) / totalCount);
                    549:   printf ("%u redundant entries (%u%%)\n",
                    550:          totalEntries - totalUniqueEntries,
                    551:          (100 * (totalEntries - totalUniqueEntries) + 50) / totalEntries);
                    552:   printf ("%.2f average lookup depth (%u maximum)\n",
                    553:          (float) totalDepth / (float) totalUniqueEntries,
                    554:          depth - 1);
                    555:   printf ("%.2f average lookup chain (%u maximum)\n",
                    556:          (float) grandTotalChain / (float) totalUniqueEntries,
                    557:          maxMaxChain);
                    558:   printf ("%u miss depth\n", depth - 1);
                    559:   printf ("%.2f average miss chain (%u maximum)\n",
                    560:          (float) grandTotalMissChain / (float) totalCount,
                    561:          maxMaxMissChain);
                    562:   
                    563:   if (totalSharedData)
                    564:     printf ("%u bytes malloced data + %u bytes shared data\n",
                    565:            totalMallocedData, totalSharedData);
                    566:   else
                    567:     printf ("%u bytes malloced data\n", totalMallocedData);
                    568: }
                    569: 
                    570: #endif /* KERNEL */
                    571: 
                    572: #ifdef FREEZE
                    573: 
                    574: void volatile __S(_objc_fatal) (const char *msg)
                    575: {
                    576:   printf ("objc fatal: %s\n", msg);
                    577:   exit (1);
                    578: }
                    579: 
                    580: 
                    581: /* used by `objcopt' to freeze dry a hash table */
                    582: 
                    583: void __S(_sel_writeHashTable) (int start_addr, 
                    584:                          char *myAddressSpace,
                    585:                          char *shlibAddressSpace,
                    586:                          void **addr, int *size)
                    587: {
                    588:   hashTable *table = &dynamicHashTable;
                    589:   unsigned int frozenSize = table->count * sizeof (PHASH) +
                    590:                            table->entries * sizeof (HASH);
                    591:   PHASH *frozenTable = NXZoneMalloc (NXDefaultMallocZone(), frozenSize);
                    592:   PHASH frozenEntries = (PHASH) (frozenTable + table->count);
                    593:   PHASH vm_hashEntryList = (PHASH) (start_addr +
                    594:                                    table->count * sizeof (PHASH));
                    595:   unsigned int slot;
                    596:   
                    597:   bzero (frozenTable, frozenSize);
                    598:   
                    599:   for (slot = 0; slot < table->count; slot++)
                    600:     if (table->list[slot])
                    601:       {
                    602:        PHASH target;
                    603:        
                    604:        frozenTable[slot] = vm_hashEntryList;
                    605:        
                    606:        for (target = table->list[slot]; target; target = target->next)
                    607:          {
                    608:            frozenEntries->sel = (target->sel - myAddressSpace) +
                    609:                                 shlibAddressSpace;
                    610:            if (target->next)
                    611:              frozenEntries->next = vm_hashEntryList + 1;
                    612:            
                    613:            frozenEntries++;
                    614:            vm_hashEntryList++;
                    615:          }
                    616:       }
                    617:   
                    618:   *addr = frozenTable;
                    619:   *size = frozenSize;
                    620: }
                    621: 
                    622: const char *__S(_nameForHeader) (const struct mach_header *header)
                    623: {
                    624:   return "objcopt";
                    625: }
                    626: 
                    627: #endif /* FREEZE */

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