1 /*
2 * Copyright © 2007 Chris Wilson
3 * Copyright © 2009,2010 Red Hat, Inc.
4 * Copyright © 2011,2012 Google, Inc.
5 *
6 * This is part of HarfBuzz, a text shaping library.
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 <[email protected]>
28 * Red Hat Author(s): Behdad Esfahbod
29 * Google Author(s): Behdad Esfahbod
30 */
31
32 #ifndef HB_ATOMIC_HH
33 #define HB_ATOMIC_HH
34
35 #include "hb.hh"
36 #include "hb-meta.hh"
37
38
39 /*
40 * Atomic integers and pointers.
41 */
42
43
44 /* We need external help for these */
45
46 #if defined(hb_atomic_int_impl_add) \
47 && defined(hb_atomic_ptr_impl_get) \
48 && defined(hb_atomic_ptr_impl_cmpexch)
49
50 /* Defined externally, i.e. in config.h. */
51
52
53 #elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE)
54
55 /* C++11-style GCC primitives. We prefer these as they don't require linking to libstdc++ / libc++. */
56
57 #define _hb_memory_barrier() __sync_synchronize ()
58
59 #define hb_atomic_int_impl_add(AI, V) __atomic_fetch_add ((AI), (V), __ATOMIC_ACQ_REL)
60 #define hb_atomic_int_impl_set_relaxed(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELAXED)
61 #define hb_atomic_int_impl_set(AI, V) __atomic_store_n ((AI), (V), __ATOMIC_RELEASE)
62 #define hb_atomic_int_impl_get_relaxed(AI) __atomic_load_n ((AI), __ATOMIC_RELAXED)
63 #define hb_atomic_int_impl_get(AI) __atomic_load_n ((AI), __ATOMIC_ACQUIRE)
64
65 #define hb_atomic_ptr_impl_set_relaxed(P, V) __atomic_store_n ((P), (V), __ATOMIC_RELAXED)
66 #define hb_atomic_ptr_impl_get_relaxed(P) __atomic_load_n ((P), __ATOMIC_RELAXED)
67 #define hb_atomic_ptr_impl_get(P) __atomic_load_n ((P), __ATOMIC_ACQUIRE)
68 static inline bool
_hb_atomic_ptr_impl_cmplexch(const void ** P,const void * O_,const void * N)69 _hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
70 {
71 const void *O = O_; // Need lvalue
72 return __atomic_compare_exchange_n ((void **) P, (void **) &O, (void *) N, true, __ATOMIC_ACQ_REL, __ATOMIC_RELAXED);
73 }
74 #define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N))
75
76
77 #elif !defined(HB_NO_MT)
78
79 /* C++11 atomics. */
80
81 #include <atomic>
82
83 #define _hb_memory_barrier() std::atomic_thread_fence(std::memory_order_ack_rel)
84 #define _hb_memory_r_barrier() std::atomic_thread_fence(std::memory_order_acquire)
85 #define _hb_memory_w_barrier() std::atomic_thread_fence(std::memory_order_release)
86
87 #define hb_atomic_int_impl_add(AI, V) (reinterpret_cast<std::atomic<std::decay<decltype (*(AI))>::type> *> (AI)->fetch_add ((V), std::memory_order_acq_rel))
88 #define hb_atomic_int_impl_set_relaxed(AI, V) (reinterpret_cast<std::atomic<std::decay<decltype (*(AI))>::type> *> (AI)->store ((V), std::memory_order_relaxed))
89 #define hb_atomic_int_impl_set(AI, V) (reinterpret_cast<std::atomic<std::decay<decltype (*(AI))>::type> *> (AI)->store ((V), std::memory_order_release))
90 #define hb_atomic_int_impl_get_relaxed(AI) (reinterpret_cast<std::atomic<std::decay<decltype (*(AI))>::type> const *> (AI)->load (std::memory_order_relaxed))
91 #define hb_atomic_int_impl_get(AI) (reinterpret_cast<std::atomic<std::decay<decltype (*(AI))>::type> const *> (AI)->load (std::memory_order_acquire))
92
93 #define hb_atomic_ptr_impl_set_relaxed(P, V) (reinterpret_cast<std::atomic<void*> *> (P)->store ((V), std::memory_order_relaxed))
94 #define hb_atomic_ptr_impl_get_relaxed(P) (reinterpret_cast<std::atomic<void*> const *> (P)->load (std::memory_order_relaxed))
95 #define hb_atomic_ptr_impl_get(P) (reinterpret_cast<std::atomic<void*> *> (P)->load (std::memory_order_acquire))
96 static inline bool
_hb_atomic_ptr_impl_cmplexch(const void ** P,const void * O_,const void * N)97 _hb_atomic_ptr_impl_cmplexch (const void **P, const void *O_, const void *N)
98 {
99 const void *O = O_; // Need lvalue
100 return reinterpret_cast<std::atomic<const void*> *> (P)->compare_exchange_weak (O, N, std::memory_order_acq_rel, std::memory_order_relaxed);
101 }
102 #define hb_atomic_ptr_impl_cmpexch(P,O,N) _hb_atomic_ptr_impl_cmplexch ((const void **) (P), (O), (N))
103
104
105 #else /* defined(HB_NO_MT) */
106
107 #define hb_atomic_int_impl_add(AI, V) ((*(AI) += (V)) - (V))
108 #define _hb_memory_barrier() do {} while (0)
109 #define hb_atomic_ptr_impl_cmpexch(P,O,N) (* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)
110
111 #endif
112
113
114 /* This should never be disabled, even under HB_NO_MT.
115 * except that MSVC gives me an internal compiler error, so disabled there.
116 *
117 * https://github.com/harfbuzz/harfbuzz/pull/4119
118 */
119 #ifndef _hb_compiler_memory_r_barrier
120 #if defined(__ATOMIC_ACQUIRE) // gcc-like
_hb_compiler_memory_r_barrier()121 static inline void _hb_compiler_memory_r_barrier () { asm volatile("": : :"memory"); }
122 #elif !defined(_MSC_VER)
123 #include <atomic>
124 #define _hb_compiler_memory_r_barrier() std::atomic_signal_fence (std::memory_order_acquire)
125 #else
_hb_compiler_memory_r_barrier()126 static inline void _hb_compiler_memory_r_barrier () {}
127 #endif
128 #endif
129
130
131
132 #ifndef _hb_memory_r_barrier
133 #define _hb_memory_r_barrier() _hb_memory_barrier ()
134 #endif
135 #ifndef _hb_memory_w_barrier
136 #define _hb_memory_w_barrier() _hb_memory_barrier ()
137 #endif
138 #ifndef hb_atomic_int_impl_set_relaxed
139 #define hb_atomic_int_impl_set_relaxed(AI, V) (*(AI) = (V))
140 #endif
141 #ifndef hb_atomic_int_impl_get_relaxed
142 #define hb_atomic_int_impl_get_relaxed(AI) (*(AI))
143 #endif
144
145 #ifndef hb_atomic_ptr_impl_set_relaxed
146 #define hb_atomic_ptr_impl_set_relaxed(P, V) (*(P) = (V))
147 #endif
148 #ifndef hb_atomic_ptr_impl_get_relaxed
149 #define hb_atomic_ptr_impl_get_relaxed(P) (*(P))
150 #endif
151 #ifndef hb_atomic_int_impl_set
hb_atomic_int_impl_set(int * AI,int v)152 inline void hb_atomic_int_impl_set (int *AI, int v) { _hb_memory_w_barrier (); *AI = v; }
hb_atomic_int_impl_set(short * AI,short v)153 inline void hb_atomic_int_impl_set (short *AI, short v) { _hb_memory_w_barrier (); *AI = v; }
154 #endif
155 #ifndef hb_atomic_int_impl_get
hb_atomic_int_impl_get(const int * AI)156 inline int hb_atomic_int_impl_get (const int *AI) { int v = *AI; _hb_memory_r_barrier (); return v; }
hb_atomic_int_impl_get(const short * AI)157 inline short hb_atomic_int_impl_get (const short *AI) { short v = *AI; _hb_memory_r_barrier (); return v; }
158 #endif
159 #ifndef hb_atomic_ptr_impl_get
hb_atomic_ptr_impl_get(void ** const P)160 inline void *hb_atomic_ptr_impl_get (void ** const P) { void *v = *P; _hb_memory_r_barrier (); return v; }
161 #endif
162
163
164 struct hb_atomic_short_t
165 {
166 hb_atomic_short_t () = default;
hb_atomic_short_thb_atomic_short_t167 constexpr hb_atomic_short_t (short v) : v (v) {}
168
operator =hb_atomic_short_t169 hb_atomic_short_t& operator = (short v_) { set_relaxed (v_); return *this; }
operator shorthb_atomic_short_t170 operator short () const { return get_relaxed (); }
171
set_relaxedhb_atomic_short_t172 void set_relaxed (short v_) { hb_atomic_int_impl_set_relaxed (&v, v_); }
set_releasehb_atomic_short_t173 void set_release (short v_) { hb_atomic_int_impl_set (&v, v_); }
get_relaxedhb_atomic_short_t174 short get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); }
get_acquirehb_atomic_short_t175 short get_acquire () const { return hb_atomic_int_impl_get (&v); }
inchb_atomic_short_t176 short inc () { return hb_atomic_int_impl_add (&v, 1); }
dechb_atomic_short_t177 short dec () { return hb_atomic_int_impl_add (&v, -1); }
178
179 short v = 0;
180 };
181
182 struct hb_atomic_int_t
183 {
184 hb_atomic_int_t () = default;
hb_atomic_int_thb_atomic_int_t185 constexpr hb_atomic_int_t (int v) : v (v) {}
186
operator =hb_atomic_int_t187 hb_atomic_int_t& operator = (int v_) { set_relaxed (v_); return *this; }
operator inthb_atomic_int_t188 operator int () const { return get_relaxed (); }
189
set_relaxedhb_atomic_int_t190 void set_relaxed (int v_) { hb_atomic_int_impl_set_relaxed (&v, v_); }
set_releasehb_atomic_int_t191 void set_release (int v_) { hb_atomic_int_impl_set (&v, v_); }
get_relaxedhb_atomic_int_t192 int get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); }
get_acquirehb_atomic_int_t193 int get_acquire () const { return hb_atomic_int_impl_get (&v); }
inchb_atomic_int_t194 int inc () { return hb_atomic_int_impl_add (&v, 1); }
dechb_atomic_int_t195 int dec () { return hb_atomic_int_impl_add (&v, -1); }
196
197 int v = 0;
198 };
199
200 template <typename P>
201 struct hb_atomic_ptr_t
202 {
203 typedef hb_remove_pointer<P> T;
204
205 hb_atomic_ptr_t () = default;
hb_atomic_ptr_thb_atomic_ptr_t206 constexpr hb_atomic_ptr_t (T* v) : v (v) {}
207 hb_atomic_ptr_t (const hb_atomic_ptr_t &other) = delete;
208
inithb_atomic_ptr_t209 void init (T* v_ = nullptr) { set_relaxed (v_); }
set_relaxedhb_atomic_ptr_t210 void set_relaxed (T* v_) { hb_atomic_ptr_impl_set_relaxed (&v, v_); }
get_relaxedhb_atomic_ptr_t211 T *get_relaxed () const { return (T *) hb_atomic_ptr_impl_get_relaxed (&v); }
get_acquirehb_atomic_ptr_t212 T *get_acquire () const { return (T *) hb_atomic_ptr_impl_get ((void **) &v); }
cmpexchhb_atomic_ptr_t213 bool cmpexch (const T *old, T *new_) const { return hb_atomic_ptr_impl_cmpexch ((void **) &v, (void *) old, (void *) new_); }
214
operator ->hb_atomic_ptr_t215 T * operator -> () const { return get_acquire (); }
operator C*hb_atomic_ptr_t216 template <typename C> operator C * () const { return get_acquire (); }
217
218 T *v = nullptr;
219 };
220
hb_barrier()221 static inline bool hb_barrier ()
222 {
223 _hb_compiler_memory_r_barrier ();
224 return true;
225 }
226
227
228 #endif /* HB_ATOMIC_HH */
229