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 <chris@chris-wilson.co.uk>
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)
68static inline bool
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))
96static inline bool
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
121#define _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
126#define _hb_compiler_memory_r_barrier() do {} while (0)
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
152inline void hb_atomic_int_impl_set (int *AI, int v) { _hb_memory_w_barrier (); *AI = v; }
153inline 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
156inline int hb_atomic_int_impl_get (const int *AI) { int v = *AI; _hb_memory_r_barrier (); return v; }
157inline 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
160inline void *hb_atomic_ptr_impl_get (void ** const P) { void *v = *P; _hb_memory_r_barrier (); return v; }
161#endif
162
163
164struct hb_atomic_short_t
165{
166 hb_atomic_short_t () = default;
167 constexpr hb_atomic_short_t (short v) : v (v) {}
168
169 hb_atomic_short_t& operator = (short v_) { set_relaxed (v_); return *this; }
170 operator short () const { return get_relaxed (); }
171
172 void set_relaxed (short v_) { hb_atomic_int_impl_set_relaxed (&v, v_); }
173 void set_release (short v_) { hb_atomic_int_impl_set (&v, v_); }
174 short get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); }
175 short get_acquire () const { return hb_atomic_int_impl_get (&v); }
176 short inc () { return hb_atomic_int_impl_add (&v, 1); }
177 short dec () { return hb_atomic_int_impl_add (&v, -1); }
178
179 short v = 0;
180};
181
182struct hb_atomic_int_t
183{
184 hb_atomic_int_t () = default;
185 constexpr hb_atomic_int_t (int v) : v (v) {}
186
187 hb_atomic_int_t& operator = (int v_) { set_relaxed (v_); return *this; }
188 operator int () const { return get_relaxed (); }
189
190 void set_relaxed (int v_) { hb_atomic_int_impl_set_relaxed (&v, v_); }
191 void set_release (int v_) { hb_atomic_int_impl_set (&v, v_); }
192 int get_relaxed () const { return hb_atomic_int_impl_get_relaxed (&v); }
193 int get_acquire () const { return hb_atomic_int_impl_get (&v); }
194 int inc () { return hb_atomic_int_impl_add (&v, 1); }
195 int dec () { return hb_atomic_int_impl_add (&v, -1); }
196
197 int v = 0;
198};
199
200template <typename P>
201struct hb_atomic_ptr_t
202{
203 typedef hb_remove_pointer<P> T;
204
205 hb_atomic_ptr_t () = default;
206 constexpr hb_atomic_ptr_t (T* v) : v (v) {}
207 hb_atomic_ptr_t (const hb_atomic_ptr_t &other) = delete;
208
209 void init (T* v_ = nullptr) { set_relaxed (v_); }
210 void set_relaxed (T* v_) { hb_atomic_ptr_impl_set_relaxed (&v, v_); }
211 T *get_relaxed () const { return (T *) hb_atomic_ptr_impl_get_relaxed (&v); }
212 T *get_acquire () const { return (T *) hb_atomic_ptr_impl_get ((void **) &v); }
213 bool cmpexch (const T *old, T *new_) const { return hb_atomic_ptr_impl_cmpexch ((void **) &v, (void *) old, (void *) new_); }
214
215 T * operator -> () const { return get_acquire (); }
216 template <typename C> operator C * () const { return get_acquire (); }
217
218 T *v = nullptr;
219};
220
221
222#endif /* HB_ATOMIC_HH */
223