runtime/objc-private.h

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  *      objc-private.h
  27  *      Copyright 1988-1996, NeXT Software, Inc.
  28  */
  29
  30 #if !defined(_OBJC_PRIVATE_H_)
  31     #define _OBJC_PRIVATE_H_
  32
  33     #import <objc/objc-api.h>   // for OBJC_EXPORT
  34
  35     OBJC_EXPORT void checkUniqueness();
  36
  37     #import "objc-config.h"
  38
  39     #import <pthread.h>
  40     #import <errno.h>
  41     #import <limits.h>
  42     #import <unistd.h>
  43     #define     mutex_alloc()   (pthread_mutex_t*)calloc(1, sizeof(pthread_mutex_t))
  44     #define     mutex_init(m)   pthread_mutex_init(m, NULL)
  45     #define     mutex_lock(m)   pthread_mutex_lock(m)
  46     #define     mutex_try_lock(m) (! pthread_mutex_trylock(m))
  47     #define     mutex_unlock(m) pthread_mutex_unlock(m)
  48     #define     mutex_clear(m)
  49     #define     mutex_t         pthread_mutex_t*
  50     #define mutex               MUTEX_DEFINE_ERROR
  51     #import <sys/time.h>
  52
  53     #import <stdlib.h>
  54     #import <stdarg.h>
  55     #import <stdio.h>
  56     #import <string.h>
  57     #import <ctype.h>
  58
  59     #import <objc/objc-runtime.h>
  60
  61     #import <malloc/malloc.h>
  62
  63
  64 /* Opaque cookie used in _getObjc... routines.  File format independant.
  65  * This is used in place of the mach_header.  In fact, when compiling
  66  * for NEXTSTEP, this is really a (struct mach_header *).
  67  *
  68  * had been: typedef void *objc_header;
  69  */
  70 #import <mach-o/loader.h>
  71 typedef struct mach_header headerType;
  72
  73 #import <objc/Protocol.h>
  74
  75 typedef struct _ProtocolTemplate { @defs(Protocol) } ProtocolTemplate;
  76 typedef struct _NXConstantStringTemplate {
  77     Class isa;
  78     void *characters;
  79     unsigned int _length;
  80 } NXConstantStringTemplate;
  81
  82 #define OBJC_CONSTANT_STRING_PTR NXConstantStringTemplate*
  83 #define OBJC_CONSTANT_STRING_DEREF &
  84 #define OBJC_PROTOCOL_PTR ProtocolTemplate*
  85 #define OBJC_PROTOCOL_DEREF .
  86
  87 typedef struct {
  88     uint32_t version; // currently 0
  89     uint32_t flags;
  90 } objc_image_info;
  91
  92 // masks for objc_image_info.flags
  93 #define OBJC_IMAGE_IS_REPLACEMENT (1<<0)
  94 #define OBJC_IMAGE_SUPPORTS_GC (1<<1)
  95
  96
  97 #define _objcHeaderIsReplacement(h)  ((h)->info  &&  ((h)->info->flags & OBJC_IMAGE_IS_REPLACEMENT))
  98
  99 /* OBJC_IMAGE_IS_REPLACEMENT:
 100    Don't load any classes
 101    Don't load any categories
 102    Do fix up selector refs (@selector points to them)
 103    Do fix up class refs (@class and objc_msgSend points to them)
 104    Do fix up protocols (@protocol points to them)
 105    Do fix up super_class pointers in classes ([super ...] points to them)
 106    Future: do load new classes?
 107    Future: do load new categories?
 108    Future: do insert new methods on existing classes?
 109    Future: do insert new methods on existing categories?
 110 */
 111
 112 #define _objcHeaderSupportsGC(h) ((h)->info  &&  ((h)->info->flags & OBJC_IMAGE_SUPPORTS_GC))
 113
 114 /* OBJC_IMAGE_SUPPORTS_GC:
 115     was compiled with -fobjc-gc flag, regardless of whether write-barriers were issued
 116     if executable image compiled this way, then all subsequent libraries etc. must also be this way
 117 */
 118
 119 // both
 120 OBJC_EXPORT headerType **       _getObjcHeaders();
 121 OBJC_EXPORT Module              _getObjcModules(const headerType *head, int *nmodules);
 122 OBJC_EXPORT Class *             _getObjcClassRefs(headerType *head, int *nclasses);
 123 OBJC_EXPORT const struct segment_command *getsegbynamefromheader(const headerType *head, const char *segname);
 124 OBJC_EXPORT const char *        _getObjcHeaderName(const headerType *head);
 125 OBJC_EXPORT objc_image_info *   _getObjcImageInfo(const headerType *head, uint32_t *size);
 126 OBJC_EXPORT ptrdiff_t           _getImageSlide(const headerType *header);
 127
 128
 129 // internal routines for delaying binding
 130 void _objc_resolve_categories_for_class (struct objc_class * cls);
 131
 132 // someday a logging facility
 133 // ObjC is assigned the range 0xb000 - 0xbfff for first parameter
 134 #define trace(a, b, c, d) do {} while (0)
 135
 136
 137
 138 OBJC_EXPORT ProtocolTemplate * _getObjcProtocols(headerType *head, int *nprotos);
 139 OBJC_EXPORT NXConstantStringTemplate *_getObjcStringObjects(headerType *head, int *nstrs);
 140 OBJC_EXPORT SEL *               _getObjcMessageRefs(headerType *head, int *nmess);
 141
 142 #define END_OF_METHODS_LIST ((struct objc_method_list*)-1)
 143
 144     typedef struct _header_info
 145     {
 146       const headerType *        mhdr;
 147       Module                    mod_ptr;                    // already slid
 148       unsigned int              mod_count;
 149       unsigned long             image_slide;
 150       const struct segment_command *    objcSegmentHeader;  // already slid
 151       objc_image_info *         info;                       // already slid
 152       struct _header_info *     next;
 153     } header_info;
 154     OBJC_EXPORT header_info *_objc_headerStart ();
 155
 156     OBJC_EXPORT int _objcModuleCount();
 157     OBJC_EXPORT const char *_objcModuleNameAtIndex(int i);
 158     OBJC_EXPORT Class objc_getOrigClass (const char *name);
 159
 160     OBJC_EXPORT const char *__S(_nameForHeader) (const headerType*);
 161
 162     OBJC_EXPORT SEL sel_registerNameNoLock(const char *str, BOOL copy);
 163     OBJC_EXPORT void sel_lock(void);
 164     OBJC_EXPORT void sel_unlock(void);
 165
 166     /* optional malloc zone for runtime data */
 167     OBJC_EXPORT malloc_zone_t *_objc_internal_zone(void);
 168     OBJC_EXPORT void *_malloc_internal(size_t size);
 169     OBJC_EXPORT void *_calloc_internal(size_t count, size_t size);
 170     OBJC_EXPORT void *_realloc_internal(void *ptr, size_t size);
 171     OBJC_EXPORT char *_strdup_internal(const char *str);
 172     OBJC_EXPORT void _free_internal(void *ptr);
 173
 174     OBJC_EXPORT BOOL class_respondsToMethod(Class, SEL);
 175     OBJC_EXPORT IMP class_lookupMethod(Class, SEL);
 176     OBJC_EXPORT IMP lookupNamedMethodInMethodList(struct objc_method_list *mlist, const char *meth_name);
 177     OBJC_EXPORT void _objc_insertMethods(struct objc_class *cls, struct objc_method_list *mlist);
 178     OBJC_EXPORT void _objc_removeMethods(struct objc_class *cls, struct objc_method_list *mlist);
 179
 180     OBJC_EXPORT IMP _cache_getImp(Class cls, SEL sel);
 181     OBJC_EXPORT Method _cache_getMethod(Class cls, SEL sel, IMP objc_msgForward_imp);
 182
 183     /* message dispatcher */
 184     OBJC_EXPORT IMP _class_lookupMethodAndLoadCache(Class, SEL);
 185     OBJC_EXPORT id _objc_msgForward (id self, SEL sel, ...);
 186
 187     /* errors */
 188     OBJC_EXPORT volatile void _objc_fatal(const char *fmt, ...);
 189     OBJC_EXPORT volatile void _objc_error(id, const char *, va_list);
 190     OBJC_EXPORT volatile void __objc_error(id, const char *, ...);
 191     OBJC_EXPORT void _objc_inform(const char *fmt, ...);
 192     OBJC_EXPORT void _objc_syslog(const char *fmt, ...);
 193
 194     /* magic */
 195     OBJC_EXPORT Class _objc_getFreedObjectClass (void);
 196 #ifndef OBJC_INSTRUMENTED
 197     OBJC_EXPORT const struct objc_cache emptyCache;
 198 #else
 199     OBJC_EXPORT struct objc_cache emptyCache;
 200 #endif
 201     OBJC_EXPORT void _objc_flush_caches (Class cls);
 202
 203     /* locking */
 204     #define MUTEX_TYPE pthread_mutex_t*
 205     #define OBJC_DECLARE_LOCK(MTX) pthread_mutex_t MTX = PTHREAD_MUTEX_INITIALIZER
 206     OBJC_EXPORT pthread_mutex_t classLock;
 207     OBJC_EXPORT pthread_mutex_t methodListLock;
 208
 209     /* nil handler object */
 210     OBJC_EXPORT id _objc_nilReceiver;
 211     OBJC_EXPORT id _objc_setNilReceiver(id newNilReceiver);
 212     OBJC_EXPORT id _objc_getNilReceiver(void);
 213
 214     /* C++ interoperability */
 215     OBJC_EXPORT SEL cxx_construct_sel;
 216     OBJC_EXPORT SEL cxx_destruct_sel;
 217     OBJC_EXPORT const char *cxx_construct_name;
 218     OBJC_EXPORT const char *cxx_destruct_name;
 219     OBJC_EXPORT BOOL object_cxxConstruct(id obj);
 220     OBJC_EXPORT void object_cxxDestruct(id obj);
 221
 222     /* GC and RTP startup */
 223     OBJC_EXPORT void gc_init(BOOL on);
 224     OBJC_EXPORT void rtp_init(void);
 225
 226     /* Write barrier implementations */
 227     OBJC_EXPORT id objc_assign_strongCast_gc(id val, id *dest);
 228     OBJC_EXPORT id objc_assign_global_gc(id val, id *dest);
 229     OBJC_EXPORT id objc_assign_ivar_gc(id value, id dest, unsigned int offset);
 230     OBJC_EXPORT id objc_assign_strongCast_non_gc(id value, id *dest);
 231     OBJC_EXPORT id objc_assign_global_non_gc(id value, id *dest);
 232     OBJC_EXPORT id objc_assign_ivar_non_gc(id value, id dest, unsigned int offset);
 233
 234     /* Code modification */
 235 #if defined(__ppc__)
 236     OBJC_EXPORT size_t objc_write_branch(void *entry, void *target);
 237 #endif
 238
 239     /* Thread-safe info field */
 240     OBJC_EXPORT void _class_setInfo(struct objc_class *cls, long set);
 241     OBJC_EXPORT void _class_clearInfo(struct objc_class *cls, long clear);
 242     OBJC_EXPORT void _class_changeInfo(struct objc_class *cls, long set, long clear);
 243
 244     /* Secure /tmp usage */
 245     OBJC_EXPORT int secure_open(const char *filename, int flags, uid_t euid);
 246
 247     typedef struct {
 248        long addressOffset;
 249        long selectorOffset;
 250     } FixupEntry;
 251
 252     static inline int selEqual( SEL s1, SEL s2 ) {
 253        return (s1 == s2);
 254     }
 255
 256     #define OBJC_LOCK(MUTEX)    mutex_lock (MUTEX)
 257     #define OBJC_UNLOCK(MUTEX)  mutex_unlock (MUTEX)
 258     #define OBJC_TRYLOCK(MUTEX) mutex_try_lock (MUTEX)
 259
 260 #if !defined(SEG_OBJC)
 261 #define SEG_OBJC        "__OBJC"        /* objective-C runtime segment */
 262 #endif
 263
 264
 265 // Settings from environment variables
 266 OBJC_EXPORT int PrintImages;     // env OBJC_PRINT_IMAGES
 267 OBJC_EXPORT int PrintLoading;    // env OBJC_PRINT_LOAD_METHODS
 268 OBJC_EXPORT int PrintConnecting; // env OBJC_PRINT_CLASS_CONNECTION
 269 OBJC_EXPORT int PrintRTP;        // env OBJC_PRINT_RTP
 270 OBJC_EXPORT int PrintGC;         // env OBJC_PRINT_GC
 271 OBJC_EXPORT int PrintSharing;    // env OBJC_PRINT_SHARING
 272 OBJC_EXPORT int PrintCxxCtors;   // env OBJC_PRINT_CXX_CTORS
 273
 274 OBJC_EXPORT int UseInternalZone; // env OBJC_USE_INTERNAL_ZONE
 275 OBJC_EXPORT int AllowInterposing;// env OBJC_ALLOW_INTERPOSING
 276
 277 OBJC_EXPORT int DebugUnload;     // env OBJC_DEBUG_UNLOAD
 278 OBJC_EXPORT int DebugFragileSuperclasses; // env OBJC_DEBUG_FRAGILE_SUPERCLASSES
 279
 280 OBJC_EXPORT int ForceGC;         // env OBJC_FORCE_GC
 281 OBJC_EXPORT int ForceNoGC;       // env OBJC_FORCE_NO_GC
 282 OBJC_EXPORT int CheckFinalizers; // env OBJC_CHECK_FINALIZERS
 283
 284 OBJC_EXPORT BOOL UseGC;          // equivalent to calling objc_collecting_enabled()
 285
 286 static __inline__ int _objc_strcmp(const unsigned char *s1, const unsigned char *s2) {
 287     unsigned char c1, c2;
 288     for ( ; (c1 = *s1) == (c2 = *s2); s1++, s2++)
 289         if (c1 == '\0')
 290             return 0;
 291     return (c1 - c2);
 292 }
 293
 294 static __inline__ unsigned int _objc_strhash(const unsigned char *s) {
 295     unsigned int hash = 0;
 296     for (;;) {
 297         int a = *s++;
 298         if (0 == a) break;
 299         hash += (hash << 8) + a;
 300     }
 301     return hash;
 302 }
 303
 304
 305 // objc per-thread storage
 306 OBJC_EXPORT pthread_key_t _objc_pthread_key;
 307 typedef struct {
 308     struct _objc_initializing_classes *initializingClasses; // for +initialize
 309
 310     // If you add new fields here, don't forget to update
 311     // _objc_pthread_destroyspecific()
 312
 313 } _objc_pthread_data;
 314
 315
 316 // Class state
 317 #define ISCLASS(cls)            ((((struct objc_class *) cls)->info & CLS_CLASS) != 0)
 318 #define ISMETA(cls)             ((((struct objc_class *) cls)->info & CLS_META) != 0)
 319 #define GETMETA(cls)            (ISMETA(cls) ? ((struct objc_class *) cls) : ((struct objc_class *) cls)->isa)
 320 #define ISINITIALIZED(cls)      ((((volatile long)GETMETA(cls)->info) & CLS_INITIALIZED) != 0)
 321 #define ISINITIALIZING(cls)     ((((volatile long)GETMETA(cls)->info) & CLS_INITIALIZING) != 0)
 322
 323
 324 // Attribute for global variables to keep them out of bss storage
 325 // To save one page per non-Objective-C process, variables used in
 326 // the "Objective-C not used" case should not be in bss storage.
 327 // On Tiger, this reduces the number of touched pages for each
 328 // CoreFoundation-only process from three to two. See #3857126 and #3857136.
 329 #define NOBSS __attribute__((section("__DATA,__data")))
 330
 331 // +load implementation
 332 #define CLS_HAS_LOAD_METHOD     0x8000L
 333
 334 #endif /* _OBJC_PRIVATE_H_ */
 335