runtime/objc-auto.h

   1 /*
   2  * Copyright (c) 2004-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #ifndef _OBJC_AUTO_H_
  25 #define _OBJC_AUTO_H_
  26
  27 #pragma GCC system_header
  28
  29 #include <objc/objc.h>
  30 #include <malloc/malloc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <string.h>
  34 #include <Availability.h>
  35 #include <TargetConditionals.h>
  36
  37 #if !TARGET_OS_WIN32
  38 #include <sys/types.h>
  39 #include <libkern/OSAtomic.h>
  40 #else
  41 #   define WINVER 0x0501                // target Windows XP and later
  42 #   define _WIN32_WINNT 0x0501  // target Windows XP and later
  43 #   define WIN32_LEAN_AND_MEAN
  44 // workaround: windef.h typedefs BOOL as int
  45 #   define BOOL WINBOOL
  46 #   include <windows.h>
  47 #   undef BOOL
  48 #endif
  49
  50
  51 /* GC is unsupported on some architectures. */
  52
  53 #if TARGET_OS_EMBEDDED  ||  TARGET_OS_IPHONE  ||  TARGET_OS_WIN32
  54 #   define OBJC_NO_GC 1
  55 #endif
  56
  57
  58 /* objc_collect() options */
  59 enum {
  60     // choose one
  61     OBJC_RATIO_COLLECTION        = (0 << 0),  // run "ratio" generational collections, then a full
  62     OBJC_GENERATIONAL_COLLECTION = (1 << 0),  // run fast incremental collection
  63     OBJC_FULL_COLLECTION         = (2 << 0),  // run full collection.
  64     OBJC_EXHAUSTIVE_COLLECTION   = (3 << 0),  // run full collections until memory available stops improving
  65
  66     OBJC_COLLECT_IF_NEEDED       = (1 << 3), // run collection only if needed (allocation threshold exceeded)
  67     OBJC_WAIT_UNTIL_DONE         = (1 << 4), // wait (when possible) for collection to end before returning (when collector is running on dedicated thread)
  68 };
  69
  70 /* objc_clear_stack() options */
  71 enum {
  72     OBJC_CLEAR_RESIDENT_STACK = (1 << 0)
  73 };
  74
  75 #ifndef OBJC_NO_GC
  76
  77
  78 /* GC declarations */
  79
  80 /* Collection utilities */
  81
  82 OBJC_EXPORT void objc_collect(unsigned long options)
  83     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
  84 OBJC_EXPORT BOOL objc_collectingEnabled(void)
  85     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  86 OBJC_EXPORT malloc_zone_t *objc_collectableZone(void)
  87     __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
  88
  89 /* GC configuration */
  90
  91 /* Tells collector to wait until specified bytes have been allocated before trying to collect again. */
  92 OBJC_EXPORT void objc_setCollectionThreshold(size_t threshold)
  93     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  94
  95 /* Tells collector to run a full collection for every ratio generational collections. */
  96 OBJC_EXPORT void objc_setCollectionRatio(size_t ratio)
  97     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  98
  99 //
 100 // GC-safe compare-and-swap
 101 //
 102
 103 /* Atomic update, with write barrier. */
 104 OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 105     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 106 /* "Barrier" version also includes memory barrier. */
 107 OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 108     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 109
 110 // atomic update of a global variable
 111 OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
 112     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 113 OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
 114     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 115 // atomic update of an instance variable
 116 OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
 117     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 118 OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
 119     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 120
 121
 122 //
 123 // Read and write barriers
 124 //
 125
 126 OBJC_EXPORT id objc_assign_strongCast(id val, id *dest)
 127     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 128 OBJC_EXPORT id objc_assign_global(id val, id *dest)
 129     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 130 OBJC_EXPORT id objc_assign_threadlocal(id val, id *dest)
 131     __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
 132 OBJC_EXPORT id objc_assign_ivar(id value, id dest, ptrdiff_t offset)
 133     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 134 OBJC_EXPORT void *objc_memmove_collectable(void *dst, const void *src, size_t size)
 135     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 136
 137 OBJC_EXPORT id objc_read_weak(id *location)
 138     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 139 OBJC_EXPORT id objc_assign_weak(id value, id *location)
 140     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 141
 142
 143 //
 144 // Thread management
 145 //
 146
 147 /* Register the calling thread with the garbage collector. */
 148 OBJC_EXPORT void objc_registerThreadWithCollector(void)
 149     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 150
 151 /* Unregisters the calling thread with the garbage collector.
 152    Unregistration also happens automatically at thread exit. */
 153 OBJC_EXPORT void objc_unregisterThreadWithCollector(void)
 154     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 155
 156 /* To be called from code which must only execute on a registered thread. */
 157 /* If the calling thread is unregistered then an error message is emitted and the thread is implicitly registered. */
 158 OBJC_EXPORT void objc_assertRegisteredThreadWithCollector(void)
 159     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 160
 161 /* Erases any stale references in unused parts of the stack. */
 162 OBJC_EXPORT void objc_clear_stack(unsigned long options)
 163     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 164
 165
 166 //
 167 // Finalization
 168 //
 169
 170 /* Returns true if object has been scheduled for finalization.  Can be used to avoid operations that may lead to resurrection, which are fatal. */
 171 OBJC_EXPORT BOOL objc_is_finalized(void *ptr)
 172     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 173
 174 // Deprcated. Tells runtime to issue finalize calls on the main thread only.
 175 OBJC_EXPORT void objc_finalizeOnMainThread(Class cls)
 176     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 177
 178
 179 //
 180 // Deprecated names.
 181 //
 182
 183 /* Deprecated. Use objc_collectingEnabled() instead. */
 184 OBJC_EXPORT BOOL objc_collecting_enabled(void)
 185     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 186 /* Deprecated. Use objc_setCollectionThreshold() instead. */
 187 OBJC_EXPORT void objc_set_collection_threshold(size_t threshold)
 188     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 189 /* Deprecated. Use objc_setCollectionRatio() instead. */
 190 OBJC_EXPORT void objc_set_collection_ratio(size_t ratio)
 191     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 192 /* Deprecated. Use objc_startCollectorThread() instead. */
 193 OBJC_EXPORT void objc_start_collector_thread(void)
 194     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 195 /* Deprecated. No replacement. Formerly told the collector to run using a dedicated background thread. */
 196 OBJC_EXPORT void objc_startCollectorThread(void)
 197 __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5,__MAC_10_7, __IPHONE_NA,__IPHONE_NA);
 198
 199
 200 /* Deprecated. Use class_createInstance() instead. */
 201 OBJC_EXPORT id objc_allocate_object(Class cls, int extra)
 202 __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_4, __IPHONE_NA,__IPHONE_NA);
 203
 204
 205 /* !defined(OBJC_NO_GC) */
 206 #else
 207 /* defined(OBJC_NO_GC) */
 208
 209
 210 /* Non-GC declarations */
 211
 212 static OBJC_INLINE void objc_collect(unsigned long options __unused) { }
 213 static OBJC_INLINE BOOL objc_collectingEnabled(void) { return NO; }
 214 static OBJC_INLINE void objc_setCollectionThreshold(size_t threshold __unused) { }
 215 static OBJC_INLINE void objc_setCollectionRatio(size_t ratio __unused) { }
 216 static OBJC_INLINE void objc_startCollectorThread(void) { }
 217
 218 #if __has_feature(objc_arc)
 219
 220 /* Covers for GC memory operations are unavailable in ARC */
 221
 222 #else
 223
 224 #if TARGET_OS_WIN32
 225 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 226     { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }
 227
 228 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 229     { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }
 230 #else
 231 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 232     { return OSAtomicCompareAndSwapPtr((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }
 233
 234 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 235     { return OSAtomicCompareAndSwapPtrBarrier((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }
 236 #endif
 237
 238 static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
 239     { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
 240
 241 static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
 242     { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
 243
 244 static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
 245     { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
 246
 247 static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
 248     { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
 249
 250
 251 static OBJC_INLINE id objc_assign_strongCast(id val, id *dest)
 252     { return (*dest = val); }
 253
 254 static OBJC_INLINE id objc_assign_global(id val, id *dest)
 255     { return (*dest = val); }
 256
 257 static OBJC_INLINE id objc_assign_ivar(id val, id dest, ptrdiff_t offset)
 258     { return (*(id*)((char *)dest+offset) = val); }
 259
 260 static OBJC_INLINE id objc_read_weak(id *location)
 261     { return *location; }
 262
 263 static OBJC_INLINE id objc_assign_weak(id value, id *location)
 264     { return (*location = value); }
 265
 266 /* MRC */
 267 #endif
 268
 269 static OBJC_INLINE void *objc_memmove_collectable(void *dst, const void *src, size_t size)
 270     { return memmove(dst, src, size); }
 271
 272 static OBJC_INLINE void objc_finalizeOnMainThread(Class cls __unused) { }
 273 static OBJC_INLINE BOOL objc_is_finalized(void *ptr __unused) { return NO; }
 274 static OBJC_INLINE void objc_clear_stack(unsigned long options __unused) { }
 275
 276 static OBJC_INLINE BOOL objc_collecting_enabled(void) { return NO; }
 277 static OBJC_INLINE void objc_set_collection_threshold(size_t threshold __unused) { }
 278 static OBJC_INLINE void objc_set_collection_ratio(size_t ratio __unused) { }
 279 static OBJC_INLINE void objc_start_collector_thread(void) { }
 280
 281 #if __has_feature(objc_arc)
 282 extern id objc_allocate_object(Class cls, int extra) UNAVAILABLE_ATTRIBUTE;
 283 #else
 284 OBJC_EXPORT id class_createInstance(Class cls, size_t extraBytes)
 285     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 286 static OBJC_INLINE id objc_allocate_object(Class cls, int extra)
 287     { return class_createInstance(cls, extra); }
 288 #endif
 289
 290 static OBJC_INLINE void objc_registerThreadWithCollector() { }
 291 static OBJC_INLINE void objc_unregisterThreadWithCollector() { }
 292 static OBJC_INLINE void objc_assertRegisteredThreadWithCollector() { }
 293
 294 /* defined(OBJC_NO_GC) */
 295 #endif
 296
 297
 298 #if TARGET_OS_EMBEDDED
 299 enum {
 300     OBJC_GENERATIONAL = (1 << 0)
 301 };
 302 static OBJC_INLINE void objc_collect_if_needed(unsigned long options) __attribute__((deprecated));
 303 static OBJC_INLINE void objc_collect_if_needed(unsigned long options __unused) { }
 304 #endif
 305
 306 #endif