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 #include <objc/objc.h>
  28 #include <malloc/malloc.h>
  29 #include <stdint.h>
  30 #include <stddef.h>
  31 #include <string.h>
  32 #include <Availability.h>
  33 #include <AvailabilityMacros.h>
  34 #include <TargetConditionals.h>
  35
  36 #if !TARGET_OS_WIN32
  37 #include <sys/types.h>
  38 #include <libkern/OSAtomic.h>
  39 #else
  40 #   define WINVER 0x0501                // target Windows XP and later
  41 #   define _WIN32_WINNT 0x0501  // target Windows XP and later
  42 #   define WIN32_LEAN_AND_MEAN
  43 // workaround: windef.h typedefs BOOL as int
  44 #   define BOOL WINBOOL
  45 #   include <windows.h>
  46 #   undef BOOL
  47 #endif
  48
  49
  50 /* GC is unsupported on some architectures. */
  51
  52 #if TARGET_OS_EMBEDDED  ||  TARGET_OS_IPHONE  ||  TARGET_OS_WIN32
  53 #   define OBJC_NO_GC 1
  54 #endif
  55
  56
  57 /* objc_collect() options */
  58 enum {
  59     // choose one
  60     OBJC_RATIO_COLLECTION        = (0 << 0),  // run "ratio" generational collections, then a full
  61     OBJC_GENERATIONAL_COLLECTION = (1 << 0),  // run fast incremental collection
  62     OBJC_FULL_COLLECTION         = (2 << 0),  // run full collection.
  63     OBJC_EXHAUSTIVE_COLLECTION   = (3 << 0),  // run full collections until memory available stops improving
  64
  65     OBJC_COLLECT_IF_NEEDED       = (1 << 3), // run collection only if needed (allocation threshold exceeded)
  66     OBJC_WAIT_UNTIL_DONE         = (1 << 4), // wait (when possible) for collection to end before returning (when collector is running on dedicated thread)
  67 };
  68
  69 /* objc_clear_stack() options */
  70 enum {
  71     OBJC_CLEAR_RESIDENT_STACK = (1 << 0)
  72 };
  73
  74 #ifndef OBJC_NO_GC
  75
  76
  77 /* GC declarations */
  78
  79 /* Collection utilities */
  80
  81 OBJC_EXPORT void objc_collect(unsigned long options)
  82     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
  83 OBJC_EXPORT BOOL objc_collectingEnabled(void)
  84     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  85 OBJC_EXPORT malloc_zone_t *objc_collectableZone(void)
  86     __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
  87
  88 /* GC configuration */
  89
  90 /* Tells collector to wait until specified bytes have been allocated before trying to collect again. */
  91 OBJC_EXPORT void objc_setCollectionThreshold(size_t threshold)
  92     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  93
  94 /* Tells collector to run a full collection for every ratio generational collections. */
  95 OBJC_EXPORT void objc_setCollectionRatio(size_t ratio)
  96     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
  97
  98 //
  99 // GC-safe compare-and-swap
 100 //
 101
 102 /* Atomic update, with write barrier. */
 103 OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 104     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 105 /* "Barrier" version also includes memory barrier. */
 106 OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 107     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 108
 109 // atomic update of a global variable
 110 OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
 111     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 112 OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
 113     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 114 // atomic update of an instance variable
 115 OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
 116     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 117 OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
 118     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
 119
 120
 121 //
 122 // Read and write barriers
 123 //
 124
 125 OBJC_EXPORT id objc_assign_strongCast(id val, id *dest)
 126     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 127 OBJC_EXPORT id objc_assign_global(id val, id *dest)
 128     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 129 OBJC_EXPORT id objc_assign_threadlocal(id val, id *dest)
 130     __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
 131 OBJC_EXPORT id objc_assign_ivar(id value, id dest, ptrdiff_t offset)
 132     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 133 OBJC_EXPORT void *objc_memmove_collectable(void *dst, const void *src, size_t size)
 134     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 135
 136 OBJC_EXPORT id objc_read_weak(id *location)
 137     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 138 OBJC_EXPORT id objc_assign_weak(id value, id *location)
 139     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 140
 141
 142 //
 143 // Thread management
 144 //
 145
 146 /* Register the calling thread with the garbage collector. */
 147 OBJC_EXPORT void objc_registerThreadWithCollector(void)
 148     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 149
 150 /* Unregisters the calling thread with the garbage collector.
 151    Unregistration also happens automatically at thread exit. */
 152 OBJC_EXPORT void objc_unregisterThreadWithCollector(void)
 153     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 154
 155 /* To be called from code which must only execute on a registered thread. */
 156 /* If the calling thread is unregistered then an error message is emitted and the thread is implicitly registered. */
 157 OBJC_EXPORT void objc_assertRegisteredThreadWithCollector(void)
 158     __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
 159
 160 /* Erases any stale references in unused parts of the stack. */
 161 OBJC_EXPORT void objc_clear_stack(unsigned long options)
 162     __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
 163
 164
 165 //
 166 // Finalization
 167 //
 168
 169 /* Returns true if object has been scheduled for finalization.  Can be used to avoid operations that may lead to resurrection, which are fatal. */
 170 OBJC_EXPORT BOOL objc_is_finalized(void *ptr)
 171     __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
 172
 173 // Deprcated. Tells runtime to issue finalize calls on the main thread only.
 174 OBJC_EXPORT void objc_finalizeOnMainThread(Class cls)
 175     AVAILABLE_MAC_OS_X_VERSION_10_5_AND_LATER_BUT_DEPRECATED;
 176
 177
 178 //
 179 // Deprecated names.
 180 //
 181
 182 /* Deprecated. Use objc_collectingEnabled() instead. */
 183 OBJC_EXPORT BOOL objc_collecting_enabled(void)
 184     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 185 /* Deprecated. Use objc_setCollectionThreshold() instead. */
 186 OBJC_EXPORT void objc_set_collection_threshold(size_t threshold)
 187     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 188 /* Deprecated. Use objc_setCollectionRatio() instead. */
 189 OBJC_EXPORT void objc_set_collection_ratio(size_t ratio)
 190     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 191 /* Deprecated. Use objc_startCollectorThread() instead. */
 192 OBJC_EXPORT void objc_start_collector_thread(void)
 193     __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
 194 /* Deprecated. No replacement. Formerly told the collector to run using a dedicated background thread. */
 195 OBJC_EXPORT void objc_startCollectorThread(void)
 196 __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5,__MAC_10_7, __IPHONE_NA,__IPHONE_NA);
 197
 198
 199 /* Deprecated. Use class_createInstance() instead. */
 200 OBJC_EXPORT id objc_allocate_object(Class cls, int extra)
 201     AVAILABLE_MAC_OS_X_VERSION_10_4_AND_LATER_BUT_DEPRECATED;
 202
 203
 204 /* !defined(OBJC_NO_GC) */
 205 #else
 206 /* defined(OBJC_NO_GC) */
 207
 208
 209 /* Non-GC declarations */
 210
 211 static OBJC_INLINE void objc_collect(unsigned long options __unused) { }
 212 static OBJC_INLINE BOOL objc_collectingEnabled(void) { return NO; }
 213 static OBJC_INLINE void objc_setCollectionThreshold(size_t threshold __unused) { }
 214 static OBJC_INLINE void objc_setCollectionRatio(size_t ratio __unused) { }
 215 static OBJC_INLINE void objc_startCollectorThread(void) { }
 216
 217 #if TARGET_OS_WIN32
 218 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 219     { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }
 220
 221 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 222     { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }
 223 #else
 224 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
 225     { return OSAtomicCompareAndSwapPtr((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }
 226
 227 static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
 228     { return OSAtomicCompareAndSwapPtrBarrier((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }
 229 #endif
 230
 231 static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
 232     { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
 233
 234 static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
 235     { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
 236
 237 static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
 238     { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
 239
 240 static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
 241     { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
 242
 243
 244 static OBJC_INLINE id objc_assign_strongCast(id val, id *dest)
 245     { return (*dest = val); }
 246
 247 static OBJC_INLINE id objc_assign_global(id val, id *dest)
 248     { return (*dest = val); }
 249
 250 static OBJC_INLINE id objc_assign_ivar(id val, id dest, ptrdiff_t offset)
 251     { return (*(id*)((char *)dest+offset) = val); }
 252
 253 static OBJC_INLINE void *objc_memmove_collectable(void *dst, const void *src, size_t size)
 254     { return memmove(dst, src, size); }
 255
 256 static OBJC_INLINE id objc_read_weak(id *location)
 257     { return *location; }
 258
 259 static OBJC_INLINE id objc_assign_weak(id value, id *location)
 260     { return (*location = value); }
 261
 262 static OBJC_INLINE void objc_finalizeOnMainThread(Class cls __unused) { }
 263 static OBJC_INLINE BOOL objc_is_finalized(void *ptr __unused) { return NO; }
 264 static OBJC_INLINE void objc_clear_stack(unsigned long options __unused) { }
 265
 266 static OBJC_INLINE BOOL objc_collecting_enabled(void) { return NO; }
 267 static OBJC_INLINE void objc_set_collection_threshold(size_t threshold __unused) { }
 268 static OBJC_INLINE void objc_set_collection_ratio(size_t ratio __unused) { }
 269 static OBJC_INLINE void objc_start_collector_thread(void) { }
 270
 271 OBJC_EXPORT id class_createInstance(Class cls, size_t extraBytes)
 272     __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
 273 static OBJC_INLINE id objc_allocate_object(Class cls, int extra)
 274     { return class_createInstance(cls, extra); }
 275
 276 static OBJC_INLINE void objc_registerThreadWithCollector() { }
 277 static OBJC_INLINE void objc_unregisterThreadWithCollector() { }
 278 static OBJC_INLINE void objc_assertRegisteredThreadWithCollector() { }
 279
 280 /* defined(OBJC_NO_GC) */
 281 #endif
 282
 283
 284 #if TARGET_OS_EMBEDDED
 285 enum {
 286     OBJC_GENERATIONAL = (1 << 0)
 287 };
 288 static OBJC_INLINE void objc_collect_if_needed(unsigned long options) __attribute__((deprecated));
 289 static OBJC_INLINE void objc_collect_if_needed(unsigned long options __unused) { }
 290 #endif
 291
 292 #endif