[apple/objc4.git] / runtime / objc-auto.h

/*
 * Copyright (c) 2004-2007 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@
 */

#ifndef _OBJC_AUTO_H_
#define _OBJC_AUTO_H_

#pragma GCC system_header

#include <objc/objc.h>
#include <malloc/malloc.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include <Availability.h>
#include <AvailabilityMacros.h>
#include <TargetConditionals.h>

#if !TARGET_OS_WIN32
#include <sys/types.h>
#include <libkern/OSAtomic.h>
#else
#   define WINVER 0x0501		// target Windows XP and later
#   define _WIN32_WINNT 0x0501	// target Windows XP and later
#   define WIN32_LEAN_AND_MEAN
// workaround: windef.h typedefs BOOL as int
#   define BOOL WINBOOL
#   include <windows.h>
#   undef BOOL
#endif


/* GC is unsupported on some architectures. */

#if TARGET_OS_EMBEDDED  ||  TARGET_OS_IPHONE  ||  TARGET_OS_WIN32
#   define OBJC_NO_GC 1
#endif


/* objc_collect() options */
enum {
    // choose one
    OBJC_RATIO_COLLECTION        = (0 << 0),  // run "ratio" generational collections, then a full
    OBJC_GENERATIONAL_COLLECTION = (1 << 0),  // run fast incremental collection
    OBJC_FULL_COLLECTION         = (2 << 0),  // run full collection.
    OBJC_EXHAUSTIVE_COLLECTION   = (3 << 0),  // run full collections until memory available stops improving
    
    OBJC_COLLECT_IF_NEEDED       = (1 << 3), // run collection only if needed (allocation threshold exceeded)
    OBJC_WAIT_UNTIL_DONE         = (1 << 4), // wait (when possible) for collection to end before returning (when collector is running on dedicated thread)
};

/* objc_clear_stack() options */
enum {
    OBJC_CLEAR_RESIDENT_STACK = (1 << 0)
};

#ifndef OBJC_NO_GC


/* GC declarations */

/* Collection utilities */

OBJC_EXPORT void objc_collect(unsigned long options)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
OBJC_EXPORT BOOL objc_collectingEnabled(void)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
OBJC_EXPORT malloc_zone_t *objc_collectableZone(void) 
    __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);

/* GC configuration */

/* Tells collector to wait until specified bytes have been allocated before trying to collect again. */
OBJC_EXPORT void objc_setCollectionThreshold(size_t threshold)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);

/* Tells collector to run a full collection for every ratio generational collections. */
OBJC_EXPORT void objc_setCollectionRatio(size_t ratio)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);

// 
// GC-safe compare-and-swap
//

/* Atomic update, with write barrier. */
OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation) 
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
/* "Barrier" version also includes memory barrier. */
OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation) 
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;

// atomic update of a global variable
OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
// atomic update of an instance variable
OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;


// 
// Read and write barriers
// 

OBJC_EXPORT id objc_assign_strongCast(id val, id *dest)
    __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
OBJC_EXPORT id objc_assign_global(id val, id *dest)
    __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
OBJC_EXPORT id objc_assign_threadlocal(id val, id *dest)
    __OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
OBJC_EXPORT id objc_assign_ivar(id value, id dest, ptrdiff_t offset)
    __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
OBJC_EXPORT void *objc_memmove_collectable(void *dst, const void *src, size_t size)
    __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);

OBJC_EXPORT id objc_read_weak(id *location)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
OBJC_EXPORT id objc_assign_weak(id value, id *location)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);


//
// Thread management
// 

/* Register the calling thread with the garbage collector. */
OBJC_EXPORT void objc_registerThreadWithCollector(void)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);

/* Unregisters the calling thread with the garbage collector. 
   Unregistration also happens automatically at thread exit. */
OBJC_EXPORT void objc_unregisterThreadWithCollector(void)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);

/* To be called from code which must only execute on a registered thread. */
/* If the calling thread is unregistered then an error message is emitted and the thread is implicitly registered. */
OBJC_EXPORT void objc_assertRegisteredThreadWithCollector(void)
    __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);

/* Erases any stale references in unused parts of the stack. */
OBJC_EXPORT void objc_clear_stack(unsigned long options)
    __OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);


//
// Finalization
// 

/* Returns true if object has been scheduled for finalization.  Can be used to avoid operations that may lead to resurrection, which are fatal. */
OBJC_EXPORT BOOL objc_is_finalized(void *ptr)
    __OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);

// Deprcated. Tells runtime to issue finalize calls on the main thread only.
OBJC_EXPORT void objc_finalizeOnMainThread(Class cls)
    AVAILABLE_MAC_OS_X_VERSION_10_5_AND_LATER_BUT_DEPRECATED;


//
// Deprecated names. 
//

/* Deprecated. Use objc_collectingEnabled() instead. */
OBJC_EXPORT BOOL objc_collecting_enabled(void)
    __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
/* Deprecated. Use objc_setCollectionThreshold() instead. */
OBJC_EXPORT void objc_set_collection_threshold(size_t threshold)
    __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
/* Deprecated. Use objc_setCollectionRatio() instead. */
OBJC_EXPORT void objc_set_collection_ratio(size_t ratio)
    __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
/* Deprecated. Use objc_startCollectorThread() instead. */
OBJC_EXPORT void objc_start_collector_thread(void)
    __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
/* Deprecated. No replacement. Formerly told the collector to run using a dedicated background thread. */
OBJC_EXPORT void objc_startCollectorThread(void)
__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5,__MAC_10_7, __IPHONE_NA,__IPHONE_NA);


/* Deprecated. Use class_createInstance() instead. */
OBJC_EXPORT id objc_allocate_object(Class cls, int extra)
    AVAILABLE_MAC_OS_X_VERSION_10_4_AND_LATER_BUT_DEPRECATED;


/* !defined(OBJC_NO_GC) */
#else
/* defined(OBJC_NO_GC) */


/* Non-GC declarations */

static OBJC_INLINE void objc_collect(unsigned long options __unused) { }
static OBJC_INLINE BOOL objc_collectingEnabled(void) { return NO; }
static OBJC_INLINE void objc_setCollectionThreshold(size_t threshold __unused) { }
static OBJC_INLINE void objc_setCollectionRatio(size_t ratio __unused) { }
static OBJC_INLINE void objc_startCollectorThread(void) { }

#if __has_feature(objc_arr)

/* Covers for GC memory operations are unavailable in ARC */

#else

#if TARGET_OS_WIN32
static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation) 
    { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }

static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation) 
    { void *original = InterlockedCompareExchangePointer((void * volatile *)objectLocation, (void *)replacement, (void *)predicate); return (original == predicate); }
#else
static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation) 
    { return OSAtomicCompareAndSwapPtr((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }

static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation) 
    { return OSAtomicCompareAndSwapPtrBarrier((void *)predicate, (void *)replacement, (void * volatile *)objectLocation); }
#endif

static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation) 
    { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }

static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation) 
    { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }

static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation) 
    { return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }

static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation) 
    { return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }


static OBJC_INLINE id objc_assign_strongCast(id val, id *dest) 
    { return (*dest = val); }

static OBJC_INLINE id objc_assign_global(id val, id *dest) 
    { return (*dest = val); }

static OBJC_INLINE id objc_assign_ivar(id val, id dest, ptrdiff_t offset) 
    { return (*(id*)((char *)dest+offset) = val); }

static OBJC_INLINE id objc_read_weak(id *location) 
    { return *location; }

static OBJC_INLINE id objc_assign_weak(id value, id *location) 
    { return (*location = value); }

/* MRC */
#endif

static OBJC_INLINE void *objc_memmove_collectable(void *dst, const void *src, size_t size) 
    { return memmove(dst, src, size); }

static OBJC_INLINE void objc_finalizeOnMainThread(Class cls __unused) { }
static OBJC_INLINE BOOL objc_is_finalized(void *ptr __unused) { return NO; }
static OBJC_INLINE void objc_clear_stack(unsigned long options __unused) { }

static OBJC_INLINE BOOL objc_collecting_enabled(void) { return NO; }
static OBJC_INLINE void objc_set_collection_threshold(size_t threshold __unused) { } 
static OBJC_INLINE void objc_set_collection_ratio(size_t ratio __unused) { } 
static OBJC_INLINE void objc_start_collector_thread(void) { }

#if __has_feature(objc_arc)
extern id objc_allocate_object(Class cls, int extra) UNAVAILABLE_ATTRIBUTE;
#else
OBJC_EXPORT id class_createInstance(Class cls, size_t extraBytes)
    __OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
static OBJC_INLINE id objc_allocate_object(Class cls, int extra) 
    { return class_createInstance(cls, extra); }
#endif

static OBJC_INLINE void objc_registerThreadWithCollector() { }
static OBJC_INLINE void objc_unregisterThreadWithCollector() { }
static OBJC_INLINE void objc_assertRegisteredThreadWithCollector() { }

/* defined(OBJC_NO_GC) */
#endif


#if TARGET_OS_EMBEDDED
enum {
    OBJC_GENERATIONAL = (1 << 0)
};
static OBJC_INLINE void objc_collect_if_needed(unsigned long options) __attribute__((deprecated));
static OBJC_INLINE void objc_collect_if_needed(unsigned long options __unused) { }
#endif

#endif
Commit	Line	Data
2bfd4448	1	/*
b3962a83	2	* Copyright (c) 2004-2007 Apple Inc. All rights reserved.
2bfd4448 A	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
2bfd4448 A	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	*/
2bfd4448 A	23
	24	#ifndef _OBJC_AUTO_H_
	25	#define _OBJC_AUTO_H_
	26
cd5f04f5 A	27	#pragma GCC system_header
cd5f04f5 A	28
7af964d1	29	#include <objc/objc.h>
8972963c	30	#include <malloc/malloc.h>
b3962a83	31	#include <stdint.h>
7af964d1 A	32	#include <stddef.h>
	33	#include <string.h>
	34	#include <Availability.h>
b3962a83	35	#include <AvailabilityMacros.h>
7af964d1 A	36	#include <TargetConditionals.h>
	37
	38	#if !TARGET_OS_WIN32
	39	#include <sys/types.h>
	40	#include <libkern/OSAtomic.h>
	41	#else
	42	# define WINVER 0x0501 // target Windows XP and later
	43	# define _WIN32_WINNT 0x0501 // target Windows XP and later
	44	# define WIN32_LEAN_AND_MEAN
	45	// workaround: windef.h typedefs BOOL as int
	46	# define BOOL WINBOOL
	47	# include <windows.h>
	48	# undef BOOL
	49	#endif
	50
	51
	52	/* GC is unsupported on some architectures. */
	53
8972963c	54	#if TARGET_OS_EMBEDDED \|\| TARGET_OS_IPHONE \|\| TARGET_OS_WIN32
7af964d1 A	55	# define OBJC_NO_GC 1
	56	#endif
	57
2bfd4448	58
7af964d1	59	/* objc_collect() options */
2bfd4448	60	enum {
b3962a83 A	61	// choose one
	62	OBJC_RATIO_COLLECTION = (0 << 0), // run "ratio" generational collections, then a full
	63	OBJC_GENERATIONAL_COLLECTION = (1 << 0), // run fast incremental collection
	64	OBJC_FULL_COLLECTION = (2 << 0), // run full collection.
	65	OBJC_EXHAUSTIVE_COLLECTION = (3 << 0), // run full collections until memory available stops improving
	66
	67	OBJC_COLLECT_IF_NEEDED = (1 << 3), // run collection only if needed (allocation threshold exceeded)
	68	OBJC_WAIT_UNTIL_DONE = (1 << 4), // wait (when possible) for collection to end before returning (when collector is running on dedicated thread)
2bfd4448 A	69	};
2bfd4448 A	70
7af964d1 A	71	/* objc_clear_stack() options */
	72	enum {
	73	OBJC_CLEAR_RESIDENT_STACK = (1 << 0)
	74	};
	75
8972963c	76	#ifndef OBJC_NO_GC
7af964d1	77
7af964d1	78
8972963c	79	/* GC declarations */
2bfd4448	80
8972963c A	81	/* Collection utilities */
	82
	83	OBJC_EXPORT void objc_collect(unsigned long options)
	84	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
	85	OBJC_EXPORT BOOL objc_collectingEnabled(void)
	86	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
	87	OBJC_EXPORT malloc_zone_t *objc_collectableZone(void)
	88	__OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
2bfd4448	89
b3962a83 A	90	/* GC configuration */
	91
	92	/* Tells collector to wait until specified bytes have been allocated before trying to collect again. */
8972963c A	93	OBJC_EXPORT void objc_setCollectionThreshold(size_t threshold)
8972963c A	94	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
b3962a83 A	95
b3962a83 A	96	/* Tells collector to run a full collection for every ratio generational collections. */
8972963c A	97	OBJC_EXPORT void objc_setCollectionRatio(size_t ratio)
8972963c A	98	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
b3962a83	99
8972963c A	100	//
	101	// GC-safe compare-and-swap
	102	//
b3962a83	103
7af964d1	104	/* Atomic update, with write barrier. */
8972963c A	105	OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
8972963c A	106	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
7af964d1	107	/* "Barrier" version also includes memory barrier. */
8972963c A	108	OBJC_EXPORT BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
8972963c A	109	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
b3962a83 A	110
b3962a83 A	111	// atomic update of a global variable
8972963c A	112	OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
	113	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
	114	OBJC_EXPORT BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
	115	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
b3962a83	116	// atomic update of an instance variable
8972963c A	117	OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
	118	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
	119	OBJC_EXPORT BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
	120	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA) OBJC_ARC_UNAVAILABLE;
7af964d1	121
b3962a83	122
8972963c A	123	//
	124	// Read and write barriers
	125	//
2bfd4448	126
8972963c A	127	OBJC_EXPORT id objc_assign_strongCast(id val, id *dest)
	128	__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
	129	OBJC_EXPORT id objc_assign_global(id val, id *dest)
	130	__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
	131	OBJC_EXPORT id objc_assign_threadlocal(id val, id *dest)
	132	__OSX_AVAILABLE_STARTING(__MAC_10_7, __IPHONE_NA);
	133	OBJC_EXPORT id objc_assign_ivar(id value, id dest, ptrdiff_t offset)
	134	__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
	135	OBJC_EXPORT void objc_memmove_collectable(void dst, const void *src, size_t size)
	136	__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
	137
	138	OBJC_EXPORT id objc_read_weak(id *location)
	139	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
	140	OBJC_EXPORT id objc_assign_weak(id value, id *location)
	141	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
b3962a83 A	142
	143
	144	//
8972963c A	145	// Thread management
8972963c A	146	//
b3962a83	147
8972963c A	148	/* Register the calling thread with the garbage collector. */
	149	OBJC_EXPORT void objc_registerThreadWithCollector(void)
	150	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
b3962a83	151
8972963c A	152	/* Unregisters the calling thread with the garbage collector.
	153	Unregistration also happens automatically at thread exit. */
	154	OBJC_EXPORT void objc_unregisterThreadWithCollector(void)
	155	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
b3962a83	156
8972963c A	157	/* To be called from code which must only execute on a registered thread. */
	158	/* If the calling thread is unregistered then an error message is emitted and the thread is implicitly registered. */
	159	OBJC_EXPORT void objc_assertRegisteredThreadWithCollector(void)
	160	__OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_NA);
	161
	162	/* Erases any stale references in unused parts of the stack. */
	163	OBJC_EXPORT void objc_clear_stack(unsigned long options)
	164	__OSX_AVAILABLE_STARTING(__MAC_10_5, __IPHONE_NA);
b3962a83	165
b3962a83 A	166
b3962a83 A	167	//
8972963c A	168	// Finalization
8972963c A	169	//
b3962a83	170
8972963c A	171	/* Returns true if object has been scheduled for finalization. Can be used to avoid operations that may lead to resurrection, which are fatal. */
	172	OBJC_EXPORT BOOL objc_is_finalized(void *ptr)
	173	__OSX_AVAILABLE_STARTING(__MAC_10_4, __IPHONE_NA);
b3962a83	174
8972963c A	175	// Deprcated. Tells runtime to issue finalize calls on the main thread only.
	176	OBJC_EXPORT void objc_finalizeOnMainThread(Class cls)
	177	AVAILABLE_MAC_OS_X_VERSION_10_5_AND_LATER_BUT_DEPRECATED;
b3962a83	178
7af964d1	179
8972963c A	180	//
	181	// Deprecated names.
	182	//
	183
	184	/* Deprecated. Use objc_collectingEnabled() instead. */
	185	OBJC_EXPORT BOOL objc_collecting_enabled(void)
	186	__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
	187	/* Deprecated. Use objc_setCollectionThreshold() instead. */
	188	OBJC_EXPORT void objc_set_collection_threshold(size_t threshold)
	189	__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
	190	/* Deprecated. Use objc_setCollectionRatio() instead. */
	191	OBJC_EXPORT void objc_set_collection_ratio(size_t ratio)
	192	__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
	193	/* Deprecated. Use objc_startCollectorThread() instead. */
	194	OBJC_EXPORT void objc_start_collector_thread(void)
	195	__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_4,__MAC_10_5, __IPHONE_NA,__IPHONE_NA);
	196	/* Deprecated. No replacement. Formerly told the collector to run using a dedicated background thread. */
	197	OBJC_EXPORT void objc_startCollectorThread(void)
	198	__OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_5,__MAC_10_7, __IPHONE_NA,__IPHONE_NA);
	199
	200
	201	/* Deprecated. Use class_createInstance() instead. */
	202	OBJC_EXPORT id objc_allocate_object(Class cls, int extra)
	203	AVAILABLE_MAC_OS_X_VERSION_10_4_AND_LATER_BUT_DEPRECATED;
	204
	205
	206	/* !defined(OBJC_NO_GC) */
	207	#else
	208	/* defined(OBJC_NO_GC) */
7af964d1	209
7af964d1	210
8972963c	211	/* Non-GC declarations */
7af964d1	212
8972963c	213	static OBJC_INLINE void objc_collect(unsigned long options __unused) { }
7af964d1	214	static OBJC_INLINE BOOL objc_collectingEnabled(void) { return NO; }
8972963c A	215	static OBJC_INLINE void objc_setCollectionThreshold(size_t threshold __unused) { }
8972963c A	216	static OBJC_INLINE void objc_setCollectionRatio(size_t ratio __unused) { }
7af964d1 A	217	static OBJC_INLINE void objc_startCollectorThread(void) { }
7af964d1 A	218
cd5f04f5 A	219	#if __has_feature(objc_arr)
	220
	221	/* Covers for GC memory operations are unavailable in ARC */
	222
	223	#else
	224
7af964d1 A	225	#if TARGET_OS_WIN32
	226	static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
	227	{ void original = InterlockedCompareExchangePointer((void volatile )objectLocation, (void )replacement, (void *)predicate); return (original == predicate); }
	228
	229	static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
	230	{ void original = InterlockedCompareExchangePointer((void volatile )objectLocation, (void )replacement, (void *)predicate); return (original == predicate); }
	231	#else
	232	static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtr(id predicate, id replacement, volatile id *objectLocation)
	233	{ return OSAtomicCompareAndSwapPtr((void )predicate, (void )replacement, (void * volatile *)objectLocation); }
	234
	235	static OBJC_INLINE BOOL objc_atomicCompareAndSwapPtrBarrier(id predicate, id replacement, volatile id *objectLocation)
	236	{ return OSAtomicCompareAndSwapPtrBarrier((void )predicate, (void )replacement, (void * volatile *)objectLocation); }
	237	#endif
	238
	239	static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobal(id predicate, id replacement, volatile id *objectLocation)
	240	{ return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
	241
	242	static OBJC_INLINE BOOL objc_atomicCompareAndSwapGlobalBarrier(id predicate, id replacement, volatile id *objectLocation)
	243	{ return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
	244
	245	static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariable(id predicate, id replacement, volatile id *objectLocation)
	246	{ return objc_atomicCompareAndSwapPtr(predicate, replacement, objectLocation); }
	247
	248	static OBJC_INLINE BOOL objc_atomicCompareAndSwapInstanceVariableBarrier(id predicate, id replacement, volatile id *objectLocation)
	249	{ return objc_atomicCompareAndSwapPtrBarrier(predicate, replacement, objectLocation); }
b3962a83	250
2bfd4448	251
7af964d1 A	252	static OBJC_INLINE id objc_assign_strongCast(id val, id *dest)
	253	{ return (*dest = val); }
	254
	255	static OBJC_INLINE id objc_assign_global(id val, id *dest)
	256	{ return (*dest = val); }
	257
	258	static OBJC_INLINE id objc_assign_ivar(id val, id dest, ptrdiff_t offset)
	259	{ return ((id)((char *)dest+offset) = val); }
	260
7af964d1 A	261	static OBJC_INLINE id objc_read_weak(id *location)
	262	{ return *location; }
	263
	264	static OBJC_INLINE id objc_assign_weak(id value, id *location)
	265	{ return (*location = value); }
	266
cd5f04f5 A	267	/* MRC */
	268	#endif
	269
	270	static OBJC_INLINE void objc_memmove_collectable(void dst, const void *src, size_t size)
	271	{ return memmove(dst, src, size); }
	272
8972963c A	273	static OBJC_INLINE void objc_finalizeOnMainThread(Class cls __unused) { }
	274	static OBJC_INLINE BOOL objc_is_finalized(void *ptr __unused) { return NO; }
	275	static OBJC_INLINE void objc_clear_stack(unsigned long options __unused) { }
7af964d1 A	276
7af964d1 A	277	static OBJC_INLINE BOOL objc_collecting_enabled(void) { return NO; }
8972963c A	278	static OBJC_INLINE void objc_set_collection_threshold(size_t threshold __unused) { }
8972963c A	279	static OBJC_INLINE void objc_set_collection_ratio(size_t ratio __unused) { }
7af964d1 A	280	static OBJC_INLINE void objc_start_collector_thread(void) { }
7af964d1 A	281
cd5f04f5 A	282	#if __has_feature(objc_arc)
	283	extern id objc_allocate_object(Class cls, int extra) UNAVAILABLE_ATTRIBUTE;
	284	#else
8972963c A	285	OBJC_EXPORT id class_createInstance(Class cls, size_t extraBytes)
8972963c A	286	__OSX_AVAILABLE_STARTING(__MAC_10_0, __IPHONE_2_0);
7af964d1 A	287	static OBJC_INLINE id objc_allocate_object(Class cls, int extra)
7af964d1 A	288	{ return class_createInstance(cls, extra); }
cd5f04f5	289	#endif
7af964d1 A	290
	291	static OBJC_INLINE void objc_registerThreadWithCollector() { }
	292	static OBJC_INLINE void objc_unregisterThreadWithCollector() { }
	293	static OBJC_INLINE void objc_assertRegisteredThreadWithCollector() { }
	294
8972963c	295	/* defined(OBJC_NO_GC) */
7af964d1	296	#endif
8972963c A	297
	298
	299	#if TARGET_OS_EMBEDDED
	300	enum {
	301	OBJC_GENERATIONAL = (1 << 0)
	302	};
	303	static OBJC_INLINE void objc_collect_if_needed(unsigned long options) __attribute__((deprecated));
	304	static OBJC_INLINE void objc_collect_if_needed(unsigned long options __unused) { }
	305	#endif
	306
2bfd4448	307	#endif