1/*
2 * Mutex operations.  Originally copied from HarfBuzz.
3 *
4 * Copyright © 2007  Chris Wilson
5 * Copyright © 2009,2010  Red Hat, Inc.
6 * Copyright © 2011,2012,2013  Google, Inc.
7 *
8 * Permission is hereby granted, without written agreement and without
9 * license or royalty fees, to use, copy, modify, and distribute this
10 * software and its documentation for any purpose, provided that the
11 * above copyright notice and the following two paragraphs appear in
12 * all copies of this software.
13 *
14 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
15 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
17 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18 * DAMAGE.
19 *
20 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
21 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
23 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
24 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25 *
26 * Contributor(s):
27 *	Chris Wilson <chris@chris-wilson.co.uk>
28 * Red Hat Author(s): Behdad Esfahbod
29 * Google Author(s): Behdad Esfahbod
30 */
31
32#ifndef _FCATOMIC_H_
33#define _FCATOMIC_H_
34
35#ifdef HAVE_CONFIG_H
36#include <config.h>
37#endif
38
39
40/* atomic_int */
41
42/* We need external help for these */
43
44#if 0
45
46typedef <type> fc_atomic_int_t;
47#define FC_ATOMIC_INT_FORMAT		"<printf format for fc_atomic_int_t>"
48#define fc_atomic_int_add(AI, V)	o = (AI), (AI) += (V), o // atomic acquire/release
49
50#define fc_atomic_ptr_get(P)		*(P) // atomic acquire
51#define fc_atomic_ptr_cmpexch(P,O,N)	*(P) == (O) ? (*(P) = (N), FcTrue) : FcFalse // atomic release
52
53
54#elif !defined(FC_NO_MT) && defined(HAVE_STDATOMIC_PRIMITIVES)
55
56#include <stdatomic.h>
57
58typedef atomic_int fc_atomic_int_t;
59#define FC_ATOMIC_INT_FORMAT		"d"
60#define fc_atomic_int_add(AI, V)	atomic_fetch_add_explicit (&(AI), (V), memory_order_acq_rel)
61
62#define fc_atomic_ptr_get(P)		atomic_load_explicit ((_Atomic(void *)*) (P), memory_order_acquire)
63static inline FcBool _fc_atomic_ptr_cmpexch(_Atomic(void *)*P, void * O, _Atomic(void *) N) {
64  return atomic_compare_exchange_strong_explicit(P, &O, N, memory_order_release, memory_order_relaxed);
65}
66#define fc_atomic_ptr_cmpexch(P,O,N)	_fc_atomic_ptr_cmpexch ((_Atomic(void *)*) (P), (O), (N))
67
68/* Casting -1 to _Atomic(int) produces a compiler error with Clang (but not GCC)
69 * so we have to override FC_REF_CONSTANT_VALUE for stdatomic.h atomics.
70 * See https://bugs.llvm.org/show_bug.cgi?id=40249. */
71#define FC_REF_CONSTANT_VALUE (-1)
72
73#elif !defined(FC_NO_MT) && defined(_MSC_VER) || defined(__MINGW32__)
74
75#include "fcwindows.h"
76
77typedef LONG fc_atomic_int_t;
78#define FC_ATOMIC_INT_FORMAT		"ld"
79#define fc_atomic_int_add(AI, V)	InterlockedExchangeAdd (&(AI), (V))
80
81#define fc_atomic_ptr_get(P)		(InterlockedCompareExchangePointerAcquire ((void **) (P), NULL, NULL))
82#define fc_atomic_ptr_cmpexch(P,O,N)	(InterlockedCompareExchangePointer ((void **) (P), (void *) (N), (void *) (O)) == (void *) (O))
83
84
85#elif !defined(FC_NO_MT) && defined(__APPLE__)
86
87#include <libkern/OSAtomic.h>
88#include <AvailabilityMacros.h>
89
90typedef int fc_atomic_int_t;
91#define FC_ATOMIC_INT_FORMAT		"d"
92#define fc_atomic_int_add(AI, V)	(OSAtomicAdd32Barrier ((V), &(AI)) - (V))
93
94#if SIZEOF_VOID_P == 8
95#define fc_atomic_ptr_get(P)		OSAtomicAdd64Barrier (0, (int64_t*)(P))
96#elif SIZEOF_VOID_P == 4
97#define fc_atomic_ptr_get(P)		OSAtomicAdd32Barrier (0, (int32_t*)(P))
98#else
99#error "SIZEOF_VOID_P not 4 or 8 (assumes CHAR_BIT is 8)"
100#endif
101
102#if (MAC_OS_X_VERSION_MIN_REQUIRED >= 1050 || __IPHONE_OS_VERSION_MIN_REQUIRED >= 20100)
103#define fc_atomic_ptr_cmpexch(P,O,N)	OSAtomicCompareAndSwapPtrBarrier ((void *) (O), (void *) (N), (void **) (P))
104#else
105#if __LP64__
106#define fc_atomic_ptr_cmpexch(P,O,N)	OSAtomicCompareAndSwap64Barrier ((int64_t) (O), (int64_t) (N), (int64_t *) (P))
107#else
108#define fc_atomic_ptr_cmpexch(P,O,N)	OSAtomicCompareAndSwap32Barrier ((int32_t) (O), (int32_t) (N), (int32_t *) (P))
109#endif
110#endif
111
112
113#elif !defined(FC_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
114
115typedef int fc_atomic_int_t;
116#define FC_ATOMIC_INT_FORMAT		"d"
117#define fc_atomic_int_add(AI, V)	__sync_fetch_and_add (&(AI), (V))
118
119#define fc_atomic_ptr_get(P)		(void *) (__sync_fetch_and_add ((P), 0))
120#define fc_atomic_ptr_cmpexch(P,O,N)	__sync_bool_compare_and_swap ((P), (O), (N))
121
122
123#elif !defined(FC_NO_MT) && defined(HAVE_SOLARIS_ATOMIC_OPS)
124
125#include <atomic.h>
126#include <mbarrier.h>
127
128typedef unsigned int fc_atomic_int_t;
129#define FC_ATOMIC_INT_FORMAT		"u"
130#define fc_atomic_int_add(AI, V)	( ({__machine_rw_barrier ();}), atomic_add_int_nv (&(AI), (V)) - (V))
131
132#define fc_atomic_ptr_get(P)		( ({__machine_rw_barrier ();}), (void *) *(P))
133#define fc_atomic_ptr_cmpexch(P,O,N)	( ({__machine_rw_barrier ();}), atomic_cas_ptr ((P), (O), (N)) == (void *) (O) ? FcTrue : FcFalse)
134
135
136#elif !defined(FC_NO_MT)
137
138#define FC_ATOMIC_INT_NIL 1 /* Warn that fallback implementation is in use. */
139typedef volatile int fc_atomic_int_t;
140#define FC_ATOMIC_INT_FORMAT		"d"
141#define fc_atomic_int_add(AI, V)	(((AI) += (V)) - (V))
142
143#define fc_atomic_ptr_get(P)		((void *) *(P))
144#define fc_atomic_ptr_cmpexch(P,O,N)	(* (void * volatile *) (P) == (void *) (O) ? (* (void * volatile *) (P) = (void *) (N), FcTrue) : FcFalse)
145
146
147#else /* FC_NO_MT */
148
149typedef int fc_atomic_int_t;
150#define FC_ATOMIC_INT_FORMAT		"d"
151#define fc_atomic_int_add(AI, V)	(((AI) += (V)) - (V))
152
153#define fc_atomic_ptr_get(P)		((void *) *(P))
154#define fc_atomic_ptr_cmpexch(P,O,N)	(* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), FcTrue) : FcFalse)
155
156#endif
157
158/* reference count */
159#ifndef FC_REF_CONSTANT_VALUE
160#define FC_REF_CONSTANT_VALUE ((fc_atomic_int_t) -1)
161#endif
162#define FC_REF_CONSTANT {FC_REF_CONSTANT_VALUE}
163typedef struct _FcRef { fc_atomic_int_t count; } FcRef;
164static inline void   FcRefInit     (FcRef *r, int v) { r->count = v; }
165static inline int    FcRefInc      (FcRef *r) { return fc_atomic_int_add (r->count, +1); }
166static inline int    FcRefDec      (FcRef *r) { return fc_atomic_int_add (r->count, -1); }
167static inline int    FcRefAdd      (FcRef *r, int v) { return fc_atomic_int_add (r->count, v); }
168static inline void   FcRefSetConst (FcRef *r) { r->count = FC_REF_CONSTANT_VALUE; }
169static inline FcBool FcRefIsConst  (const FcRef *r) { return r->count == FC_REF_CONSTANT_VALUE; }
170
171#endif /* _FCATOMIC_H_ */
172